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• Johansen 2019 Comp Biochem Physiol C Toxicol Pharmacol  + (Acute exposure to crude oil and polycyclic … Acute exposure to crude oil and polycyclic aromatic hydrocarbons (PAH) can severely impair cardiorespiratory function and swim performance of larval, juvenile and adult fish. Interestingly, recent work has documented an oil induced decoupling of swim performance (Ucrit) and maximum metabolic rate (MMR) whereby oil causes a decline in Ucrit without a parallel reduction in MMR. We hypothesize that this uncoupling is due to impaired mitochondrial function in swimming muscles that results in increased proton leak, and thus less ATP generated per unit oxygen. Using high resolution mitochondrial respirometry, we assessed 11 metrics of mitochondrial performance in red and cardiac muscle from permeabilized fibers isolated from red drum following control or 24 h crude oil (high energy water accommodated fractions) exposure. Two experimental series were performed, a Deepwater Horizon relevant low dose (29.6 ± 7.4 μg L-1 ∑PAH50) and a proof-of-concept high dose (64.5 ± 8.9 μg L-1 ∑PAH50). No effects were observed on any mitochondrial parameter in either tissue at the low oil dose; however, high dose exposure provided evidence of impairment in the OXPHOS respiratory control ratio and OXPHOS spare capacity in red muscle following oil exposure, as well as a shift from Complex I to Complex II during OXPHOS respiration. No effects of the high dose oil treatment were observed in cardiac muscle. As such, mitochondrial dysfunction is unlikely to be the underlying mechanism for decoupling of Ucrit and MMR following acute oil exposure in red drum. Furthermore, mitochondrial dysfunction does not appear to be a relevant toxicological impairment in juvenile red drum with respect to the Deepwater Horizon oil spill, although impairments may be observed under higher dose exposure scenarios.</br></br><small>Copyright © 2019 Elsevier Inc. All rights reserved.</small> 2019 Elsevier Inc. All rights reserved.</small>)
• Banh 2015 Comp Biochem Physiol B Biochem Mol Biol  + (Acute heat challenge is known to induce ce … Acute heat challenge is known to induce cell-level oxidative stress in fishes. Mitochondria are well known for the capacity to make reactive oxygen species (ROS) and as such are often implicated as a source of the oxidants associated with this thermally-induced oxidative stress. This implication is often asserted, despite little direct data for mitochondrial ROS metabolism in fishes. Here we characterize mitochondrial ROS metabolism in three Actinopterygian fish species at two levels, the capacity for superoxide/H₂O₂ production and the antioxidant thiol-reductase enzyme activities. We find that red muscle mitochondria from all three species have measurable ROS production and respond to different assay conditions consistent with what might be anticipated; assuming similar relative contributions from difference ROS producing sites as found in rat skeletal muscle mitochondria. Although there are species and assay specific exceptions, fish mitochondria may have a greater capacity to produce ROS than that found in the rat when either normalized to respiratory capacity or determined at a common assay temperature. The interspecific differences in ROS production are not correlated with thiol-based antioxidant reductase activities. Moreover, mimicking an acute ''in vivo'' heat stress by comparing the impact of increasing assay temperature on these processes in vitro, we find evidence supporting a preferential activation of mitochondrial H₂O₂ production relative to the increase in the capacity of reductase enzymes to supply electrons to the mitochondrial matrix peroxidases. This supports the contention that mitochondria may be, at least in part, responsible for the ROS that lead to oxidative stress in fish tissues exposed to acute heat challenge.for the ROS that lead to oxidative stress in fish tissues exposed to acute heat challenge.)
• Calbet 2003 Am J Physiol Regul Integr Comp Physiol  + (Acute hypoxia (AH) reduces maximal O<su … Acute hypoxia (AH) reduces maximal O₂ consumption (''V''_O₂max), but after acclimatization, and despite increases in both hemoglobin concentration and arterial O₂ saturation that can normalize arterial O₂ concentration ([O₂]), ''V''_O₂max remains low. To determine why, seven lowlanders were studied at ''V''_O₂max (cycle ergometry) at sea level (SL), after 9-10 wk at 5260 m [chronic hypoxia (CH)], and 6 mo later at SL in AH (''F''_iO₂ = 0.105) equivalent to 5260 m. Pulmonary and leg indexes of O₂ transport were measured in each condition. Both cardiac output and leg blood flow were reduced by approximately 15 % in both AH and CH (''P'' < 0.05). At maximal exercise, arterial [O₂] in AH was 31 % lower than at SL (''P'' < 0.05), whereas in CH it was the same as at SL due to both polycythemia and hyperventilation. O₂ extraction by the legs, however, remained at SL values in both AH and CH. Although at both SL and in AH, 76 % of the cardiac output perfused the legs, in CH the legs received only 67 %. Pulmonary ''V''_O₂max (4.1 +/- 0.3 L/min at SL) fell to 2.2 +/- 0.1 L/min in AH (''P'' < 0.05) and was only 2.4 +/- 0.2 L/min in CH (''P'' < 0.05). These data suggest that the failure to recover ''V''_O₂max after acclimatization despite normalization of arterial [O₂] is explained by two circulatory effects of altitude: 1) failure of cardiac output to normalize and 2) preferential redistribution of cardiac output to nonexercising tissues. Oxygen transport from blood to muscle mitochondria, on the other hand, appears unaffected by CH.t;sub>2</sub>] is explained by two circulatory effects of altitude: 1) failure of cardiac output to normalize and 2) preferential redistribution of cardiac output to nonexercising tissues. Oxygen transport from blood to muscle mitochondria, on the other hand, appears unaffected by CH.)
• Wu 2007 Am J Physiol Lung Cell Mol Physiol  + (Acute hypoxia causes pulmonary vasoconstri … Acute hypoxia causes pulmonary vasoconstriction and coronary vasodilation. The divergent effects of hypoxia on pulmonary and coronary vascular smooth muscle cells suggest that the mechanisms involved in oxygen sensing and downstream effectors are different in these two types of cells. Since production of reactive oxygen species (ROS) is regulated by oxygen tension, ROS have been hypothesized to be a signaling mechanism in hypoxia-induced pulmonary vasoconstriction and vascular remodeling. Furthermore, an increased ROS production is also implicated in arteriosclerosis. In this study, we determined and compared the effects of hypoxia on ROS levels in human pulmonary arterial smooth muscle cells (PASMC) and coronary arterial smooth muscle cells (CASMC). Our results indicated that acute exposure to hypoxia (Po(2) = 25-30 mmHg for 5-10 min) significantly and rapidly decreased ROS levels in both PASMC and CASMC. However, chronic exposure to hypoxia (Po(2) = 30 mmHg for 48 h) markedly increased ROS levels in PASMC, but decreased ROS production in CASMC. Furthermore, chronic treatment with endothelin-1, a potent vasoconstrictor and mitogen, caused a significant increase in ROS production in both PASMC and CASMC. The inhibitory effect of acute hypoxia on ROS production in PASMC was also accelerated in cells chronically treated with endothelin-1. While the decreased ROS in PASMC and CASMC after acute exposure to hypoxia may reflect the lower level of oxygen substrate available for ROS production, the increased ROS production in PASMC during chronic hypoxia may reflect a pathophysiological response unique to the pulmonary vasculature that contributes to the development of pulmonary vascular remodeling in patients with hypoxia-associated pulmonary hypertension.hypoxia-associated pulmonary hypertension.)
• Cortes 2023 Nat Commun  + (Acute inflammation can either resolve thro … Acute inflammation can either resolve through immunosuppression or persist, leading to chronic inflammation. These transitions are driven by distinct molecular and metabolic reprogramming of immune cells. The anti-diabetic drug Metformin inhibits acute and chronic inflammation through mechanisms still not fully understood. Here, we report that the anti-inflammatory and reactive-oxygen-species-inhibiting effects of Metformin depend on the expression of the plasticity factor ZEB1 in macrophages. Using mice lacking Zeb1 in their myeloid cells and human patient samples, we show that ZEB1 plays a dual role, being essential in both initiating and resolving inflammation by inducing macrophages to transition into an immunosuppressed state. ZEB1 mediates these diverging effects in inflammation and immunosuppression by modulating mitochondrial content through activation of autophagy and inhibition of mitochondrial protein translation. During the transition from inflammation to immunosuppression, Metformin mimics the metabolic reprogramming of myeloid cells induced by ZEB1. Mechanistically, in immunosuppression, ZEB1 inhibits amino acid uptake, leading to downregulation of mTORC1 signalling and a decrease in mitochondrial translation in macrophages. These results identify ZEB1 as a driver of myeloid cell metabolic plasticity, suggesting that targeting its expression and function could serve as a strategy to modulate dysregulated inflammation and immunosuppression.ulated inflammation and immunosuppression.)
• Tretter 2014 Abstract MiP2014  + (Acute ischemia-reperfusion injury of the b … Acute ischemia-reperfusion injury of the brain affects millions of people. Currently there is no really efficient neuroprotective therapy, however, a simple physical procedure, therapeutic hypothermia, can have beneficial effects. Although there is agreement that in this group of diseases oxidative stress is an important factor, the effects of temperature changes on the reactive oxygen species (ROS) formation and on the ROS elimination have not been clarified yet. A few publications in high profile journals claimed that mitochondrial ROS formation was inversely related to increasing temperature. In the present work, the effects of temperature changes on H₂O₂ formation and elimination were investigated in isolated guinea pig brain mitochondria in association with oxygen consumption.</br></br>Mitochondrial ROS production was measured using Amplex UltraRed fluorescence, the rate of H₂O₂ elimination was measured using a hydrogen peroxide-sensitive electrode (WPI). Oxygen consumption of mitochondria was measured using an Oroboros Oxygraph-2k. In order to energize mitochondria glutamate plus malate, succinate and alpha-glycerophosphate substrates were used. The bioenergetic and ROS parameters of mitochondria were investigated at 33, 37 and 41 °C.</br></br>The rate of substrate oxidation showed a strong increase with temperature, whereas the efficiency of oxidation was decreased. Considering the ROS homeostasis both the formation of H₂O₂ and the elimination of H₂O₂ became faster with increasing temperature. With Complex I substrates at resting respiration, H₂O₂ production was increased by 31%, as a consequence of elevating the temperature from 33 °C to 41 °C. Using succinate or alpha-glycerophosphate, results were similar. The biggest difference (59% between 33 °C and 41 °C) was detected when H₂O₂ production was measured in the presence of the Complex I inhibitor rotenone. The rate of H₂O₂ elimination was also elevated by 24% with increased temperature (from 33 °C to 41 °C), in glutamate+malate supported mitochondria. </br></br>Rising the temperature from hypothermic to hyperthermic conditions resulted in an increase in mitochondrial oxygen consumption, H₂O₂ production and H₂O₂ elimination. The increase of ROS production was higher than that of H₂O₂ elimination; thus, according to our results, the elevation of temperature created oxidative stress conditions. We conclude that the neuroprotective effects of therapeutic hypothermia are also based on the decreased rate of mitochondrial H₂O₂ production.ub> elimination; thus, according to our results, the elevation of temperature created oxidative stress conditions. We conclude that the neuroprotective effects of therapeutic hypothermia are also based on the decreased rate of mitochondrial H₂O₂ production.)
• Lopes 2022 Int J Mol Sci  + (Acute kidney injury (AKI) caused by ischem … Acute kidney injury (AKI) caused by ischemia followed by reperfusion (I/R) is characterized by intense anion superoxide (O₂^•-) production and oxidative damage. We investigated whether extracellular vesicles secreted by adipose tissue mesenchymal cells (EVs) administered during reperfusion can suppress the exacerbated mitochondrial O₂^•- formation after I/R. We used Wistar rats subjected to bilateral renal arterial clamping (30 min) followed by 24 h of reperfusion. The animals received EVs (I/R + EVs group) or saline (I/R group) in the kidney subcapsular space. The third group consisted of false-operated rats (SHAM). Mitochondria were isolated from proximal tubule cells and used immediately. Amplex Red™ was used to measure mitochondrial O₂^•- formation and MitoTracker™ Orange to evaluate inner mitochondrial membrane potential (Δψ). ''In vitro'' studies were carried out on human renal proximal tubular cells (HK-2) co-cultured or not with EVs under hypoxic conditions. Administration of EVs restored O₂^•- formation to SHAM levels in all mitochondrial functional conditions. The gene expression of catalase and superoxide dismutase-1 remained unmodified; transcription of heme oxygenase-1 (HO-1) was upregulated. The co-cultures of HK-2 cells with EVs revealed an intense decrease in apoptosis. We conclude that the mechanisms by which EVs favor long-term recovery of renal structures and functions after I/R rely on a decrease of mitochondrial O₂^•- formation with the aid of the upregulated antioxidant HO-1/Nuclear factor erythroid 2-related factor 2 system, thus opening new vistas for the treatment of AKI.; formation with the aid of the upregulated antioxidant HO-1/Nuclear factor erythroid 2-related factor 2 system, thus opening new vistas for the treatment of AKI.)
• Patil 2014 Am J Physiol Renal Physiol  + (Acute kidney injury (AKI) is a complicatio … Acute kidney injury (AKI) is a complication of sepsis and leads to a high mortality rate. Human and animal studies suggest that mitochondrial dysfunction plays an important role in sepsis-induced multi-organ failure; however, the specific mitochondrial targets damaged during sepsis remain elusive. We used a clinically relevant cecal ligation and puncture (CLP) murine model of sepsis and assessed renal mitochondrial function using high-resolution respirometry, renal microcirculation using intravital microscopy and renal function. CLP caused a time-dependent decrease in mitochondrial complex I and II/III respiration and reduced ATP. By 4 hours after CLP, activity of manganese superoxide dismutase (MnSOD) was decreased by 50% and inhibition was sustained through 36 hours. These events were associated with increased mitochondrial superoxide generation. We then evaluated whether the mitochondria-targeted antioxidant Mito-TEMPO could reverse renal mitochondrial dysfunction and attenuate sepsis-induced AKI. Mito-TEMPO (10 mg/kg) given at 6 hours post CLP decreased mitochondrial superoxide levels, protected complex I and II/III respiration, and restored MnSOD activity by 18 hours. Mito-TEMPO also improved renal microcirculation and glomerular filtration rate. Importantly, even delayed therapy with a single dose of Mito-TEMPO significantly increased 96-hour survival rate from 40% in untreated septic mice to 80%. Thus, sepsis causes sustained inactivation of three mitochondrial targets that can lead to increased mitochondrial superoxide. Importantly, even delayed therapy with Mito-TEMPO alleviated kidney injury, suggesting that it may be a promising approach to treat septic AKI. a promising approach to treat septic AKI.)
• Quoilin 2014 Dissertation  + (Acute kidney injury (AKI) is a frequent co … Acute kidney injury (AKI) is a frequent complication of sepsis that can increase mortality as high as 70%. The pathophysiology of this kidney failure</br>was previously believed to be secondary to decreased global renal perfusion causing hypoxia-induced injury. However, new research suggests this paradigm is overly simplistic, and injury is now considered multifactorial in origin. Mechanisms that contribute to kidney injury mainly include inflammation, alterations in microvascular renal blood flow and changes in bioenergetics.</br></br>To study the mechanism of oxygen regulation in acute kidney injury during sepsis, we developed a sepsis-induced ''in vitro'' model using proximal tubular epithelial cells (HK-2) exposed to a bacterial endotoxin (lipopolysaccharide, LPS). Our first investigation, by using both high-resolution respirometry and electron spin resonance spectroscopy, showed that HK-2 cells exhibit a decreased oxygen consumption rate when treated with LPS. Surprisingly,this cellular respiration alteration persists even after the stress factor is removed. We suggested that this irreversible decrease in renal oxygen consumption after LPS challenge is related to a pathologic metabolic down-regulation such as a lack of oxygen utilization by cells for ATP production. In the long term, this metabolic disturbance leads cells to a predominantly</br>apoptotic death. cells to a predominantly apoptotic death.)
• Li 2022 Mol Med  + (Acute kidney injury (AKI) is still a criti … Acute kidney injury (AKI) is still a critical problem in clinical practice, with a heavy burden for national health system around the world. It is notable that sepsis is the predominant cause of AKI for patients in the intensive care unit and the mortality remains considerably high. The treatment for AKI relies on supportive therapies and almost no specific treatment is currently available. Spermidine is a naturally occurring polyamine with pleiotropic effects. However, the renoprotective effect of spermidine and the underlying mechanism remain elusive.</br></br>We employed mice sepsis-induced AKI model and explored the potential renoprotective effect of spermidine ''in vivo'' with different administration time and routes. Macrophage depleting was utilized to probe the role of macrophage. ''In vitro'' experiments were conducted to examine the effect of spermidine on macrophage cytokine secretion, NLRP3 inflammasome activation and mitochondrial respiration.</br></br>We confirmed that spermidine improves AKI with different administration time and routes and that macrophages serves as an essential mediator in this protective effect. Meanwhile, spermidine downregulates NOD-like receptor protein 3 (NLRP3) inflammasome activation and IL-1 beta production in macrophages directly. Mechanically, spermidine enhances mitochondrial respiration capacity and maintains mitochondria function which contribute to the NLRP3 inhibition. Importantly, we showed that eukaryotic initiation factor 5A (eIF5A) hypusination plays an important role in regulating macrophage bioactivity.</br></br>Spermidine administration practically protects against sepsis-induced AKI in mice and macrophages serve as an essential mediator in this protective effect. Our study identifies spermidine as a promising pharmacologic approach to prevent AKI.ing pharmacologic approach to prevent AKI.)
• Zhang 2019 Biochem Biophys Res Commun  + (Acute liver injury seriously endangers hum … Acute liver injury seriously endangers human health. Liraglutide, a glucagon-like peptide-1 (GLP-1) analogue, has antioxidative effects in addition to being widely used in the treatment of type 2 diabetes and was reported to ameliorate liver diseases. The aim of this study was to evaluate the hepatoprotective effects of liraglutide on carbon tetrachloride (CCl4)-induced acute liver injury in mice and to investigate the mechanisms involved in this protective effect. Male BALB/c mice were pre-treated with liraglutide (200 μg/kg/day) by hypodermic injection for 3 days before a 0.1% (v/v) CCl4 (10 ml/kg, dissolved in olive oil) intraperitoneal injection, or post-treated with liraglutide once immediately after a CCl4 intraperitoneal injection. The experimental data showed that liraglutide treatment significantly decreased the serum ALT and AST levels and ameliorated the liver histopathological changes induced by CCl4. In addition, liraglutide pre-treatment dramatically increased the number of proliferating cell nuclear antigen (PCNA)-positive hepatocytes and significantly reduced hepatocyte apoptosis after CCl4 treatment. As a consequence, liraglutide pre-treatment significantly prevented CCl4-induced malondialdehyde (MDA) production and increased the activity of the antioxidant superoxide dismutase (SOD) enzyme. In addition, liraglutide pre-treatment significantly ameliorated mitochondrial respiratory functions and ultrastructural features. Furthermore, liraglutide pre-treatment enhances the activation of the NRF2/HO-1 signaling pathway. In summary, liraglutide protects against CCl4-induced acute liver injury by protecting mitochondrial functions and inhibiting oxidative stress, which may partly involve the activation of NRF2/HO-1 signaling pathway.</br></br><small>Copyright © 2019 Elsevier Inc. All rights reserved.</small> 2019 Elsevier Inc. All rights reserved.</small>)
• Canevarolo 2017 Thesis  + (Acute lymphoblastic leukemia (ALL) is the … Acute lymphoblastic leukemia (ALL) is the most common type of childhood cancer, accounting for 25% of all cancers in this age group. One of the chemotherapeutics used in the therapy of ALL (and autoimmune diseases such as rheumatoid arthritis) is methotrexate (MTX), a folic acid antagonist (antifolate). As a chemotherapeutic agent, MTX´s mechanism of action is primarily attributed to the inhibition of the dihydrophate reductase enzyme, which synthesizes tetrahydrofolate from dihydrofolate – a key step in the ''de novo'' synthesis of purine nucleotides used in cell division. In rheumatoid arthritis, lower doses of MTX inhibit the 5-aminoimidazole-4-ribonucleotide-carboxamide formyltransferase (ATIC) enzyme, which culminates in the production of high levels of adenosine, a potent anti-inflammatory. However, recent works continue to present previously unknown mechanisms and effects through which MTX acts within the cell, attesting that MTX´s mechanisms of action appear to be as multiple as complex. Using several techniques of molecular biology, this work sought to expand the existing knowledge of the action of MTX in ALL. For this purpose, several</br>biological parameters were measured under or without MTX treatment in a panel of 13 ALL</br>cell lines. Proliferation tests, metabolic studies, drug synergism, quantification of cellular</br>respiration and the production of reactive oxygen species (ROS) were performed, as well as</br>the measurement of the activation of the NF-κB signaling pathway. Resistance of the MTX</br>strains within 48 h of treatment (but not 96 h) was related to the proliferation rate of the cells.</br>Treatment with MTX altered the concentration of 28 intracellular metabolites, highlights for a</br>consistent increase in glycine concentration. Intracellular concentrations of asparagine,</br>guanosine and glutathione – including the expression of genes from glutathione pathway –</br>were associated with MTX resistance. Supplementation of the culture medium with Nacetylcysteine,</br>a precursor metabolite of glutathione, promoted proliferation and resistance to</br>MTX; however, cell treatment with piperlongumine or hydrogen peroxide, two glutathione</br>scavengers and ROS promoters, did not potentiate the effect of MTX. MTX induced ROS in</br>ALL after 6 h of treatment with low fold change, though. Paradoxically, higher ROS</br>production was found in cell lines with high MTX resistance and intracellular glutathione.</br>The oxygen uptake of the cell lines was not associated with MTX resistance and a preliminary</br>test showed that MTX did not alter cellular respiration. MTX activated the transcription factor</br>NF-κB in some ALL cell lines and, interestingly, the activation of this transcription factor by</br>tumor necrosis factor alpha (TNF-α) was positively correlated with the resistance of leukemic</br>lines to MTX. A wide bibliographic review allowed both the integration of the obtained</br>results to the most current knowledge on the subject, and the identification of new paths to be</br>explored in future stages.new paths to be explored in future stages.)
• Warren 2017 Metabolism  + (Acute metabolic demands that promote exces … Acute metabolic demands that promote excessive and/or prolonged reactive oxygen species production may stimulate changes in mitochondrial oxidative capacity.</br></br>To assess changes in skeletal muscle H₂O₂ production, mitochondrial function, and expression of genes at the mRNA and protein levels regulating energy metabolism and mitochondrial dynamics following a hyperinsulinemic-euglycemic clamp in a cohort of 11 healthy premenopausal women.</br></br>Skeletal muscle biopsies of the vastus lateralis were taken at baseline and immediately following the conclusion of a hyperinsulinemic-euglycemic clamp. Mitochondrial production of H₂O₂ was quantified fluorometrically and mitochondrial oxidation supported by pyruvate, malate, and succinate (PMS) or palmitoyl carnitine and malate (PCM) was measured by high-resolution respirometry in permeabilized muscle fiber bundles. mRNA and protein levels were assessed by real time PCR and Western blotting.</br></br>H₂O₂ emission increased following the clamp (P<0.05). Coupled respiration (State 3) supported by PMS and the respiratory control ratio (index of mitochondrial coupling) for both PMS and PCM were lower following the clamp (P<0.05). IRS1 mRNA decreased, whereas PGC1α and GLUT4 mRNA increased following the clamp (P≤0.05). PGC1α, IRS1, and phosphorylated AKT protein levels were higher after the clamp compared to baseline (P<0.05).</br></br>This study demonstrated that acute hyperinsulinemia induced H₂O₂ production and a concurrent decrease in coupling of mitochondrial respiration with ATP production in a cohort of healthy premenopausal women. Future studies should determine if this uncoupling ameliorates peripheral oxidative damage, and if this mechanism is impaired in diseases associated with chronic oxidative stress.</br></br>Copyright © 2017 Elsevier Inc. All rights reserved.amage, and if this mechanism is impaired in diseases associated with chronic oxidative stress. Copyright © 2017 Elsevier Inc. All rights reserved.)
• Bailey 2001 High Alt Med Biol  + (Acute mountain sickness; prophylactic bene … Acute mountain sickness; prophylactic benefits of Free-radical-mediated damage to the blood-brain barrier may be implicated in the pathophysiology of acute mountain sickness (AMS). To indirectly examine this, we conducted a randomized double-blind placebo-controlled trial to assess the potentially prophylactic benefits of enteral antioxidant vitamin supplementation during ascent to high altitude. Eighteen subjects aged 35 +/- 10 years old were randomly assigned double-blind to either an antioxidant (n = 9) or placebo group (n = 9). The antioxidant group ingested 4 capsules/day(-1) (2 after breakfast/2 after evening meal) that each contained 250 mg of L-ascorbic acid, 100 IU of dl-a-tocopherol acetate and 150 mg of alpha-lipoic acid. The placebo group ingested 4 capsules of identical external appearance, taste, and smell. Supplementation was enforced for 3 weeks at sea level and during a 10-day ascent to Mt. Everest base camp (approximately 5,180 m). Antioxidant supplementation resulted in a comparatively lower Lake Louise AMS score at high altitude relative to the placebo group (2.8 +/- 0.8 points versus 4.0 +/- 0.4 points, P = 0.036), higher resting arterial oxygen saturation (89 +/- 5% versus 85 +/- 5%, P = 0.042), and total caloric intake (13.2 +/- 0.6 MJ/day(-1) versus 10.1 +/- 0.7 MJ/day(-1), P = 0.001); the latter is attributable to a lower satiety rating following a standardized meal. These findings indicate that the exogenous provision of water and lipid-soluble antioxidant vitamins at the prescribed doses is an apparently safe and potentially effective intervention that can attenuate AMS and improve the physiological profile of mountaineers at high altitude. profile of mountaineers at high altitude.)
• Fisher-Wellman 2023 Cancers (Basel)  + (Acute myelogenous leukemia (AML), the most … Acute myelogenous leukemia (AML), the most prevalent acute and aggressive leukemia diagnosed in adults, often recurs as a difficult-to-treat, chemotherapy-resistant disease. Because chemotherapy resistance is a major obstacle to successful treatment, novel therapeutic intervention is needed. Upregulated ceramide clearance via accelerated hydrolysis and glycosylation has been shown to be an element in chemotherapy-resistant AML, a problem considering the crucial role ceramide plays in eliciting apoptosis. Herein we employed agents that block ceramide clearance to determine if such a "reset" would be of therapeutic benefit. SACLAC was utilized to limit ceramide hydrolysis, and D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-threo-PDMP) was used to block the glycosylation route. The SACLAC D-threo-PDMP inhibitor combination was synergistically cytotoxic in drug-resistant, P-glycoprotein-expressing (P-gp) AML but not in wt, P-gp-poor cells. Interestingly, P-gp antagonists that can limit ceramide glycosylation via depression of glucosylceramide transit also synergized with SACLAC, suggesting a paradoxical role for P-gp in the implementation of cell death. Mechanistically, cell death was accompanied by a complete drop in ceramide glycosylation, concomitant, striking increases in all molecular species of ceramide, diminished sphingosine 1-phosphate levels, resounding declines in mitochondrial respiratory kinetics, altered Akt, pGSK-3β, and Mcl-1 expression, and caspase activation. Although ceramide was generated in wt cells upon inhibitor exposure, mitochondrial respiration was not corrupted, suggestive of mitochondrial vulnerability in the drug-resistant phenotype, a potential therapeutic avenue. The inhibitor regimen showed efficacy in an ''in vivo'' model and in primary AML cells from patients. These results support the implementation of SL enzyme targeting to limit ceramide clearance as a therapeutic strategy in chemotherapy-resistant AML, inclusive of a novel indication for the use of P-gp antagonists.ndication for the use of P-gp antagonists.)
• Peng 2022 Front Oncol  + (Acute myeloid leukemia (AML) is a heteroge … Acute myeloid leukemia (AML) is a heterogeneous hematologic malignancy characterized by multiple cytogenetic and molecular abnormalities, with a very poor prognosis. Current treatments for AML often fail to eliminate leukemic stem cells (LSCs), which perpetuate the disease. LSCs exhibit a unique metabolic profile, especially dependent on oxidative phosphorylation (OXPHOS) for energy production. Whereas, normal hematopoietic stem cells (HSCs) and leukemic blasts rely on glycolysis for adenosine triphosphate (ATP) production. Thus, understanding the regulation of OXPHOS in LSCs may offer effective targets for developing clinical therapies in AML. This review summarizes these studies with a focus on the regulation of the electron transport chain (ETC) and tricarboxylic acid (TCA) cycle in OXPHOS and discusses potential therapies for eliminating LSCs. potential therapies for eliminating LSCs.)
• Jayasankar 2022 ACS Omega  + (Acute myeloid leukemia (AML) is an aggress … Acute myeloid leukemia (AML) is an aggressive blood cancer with limited effective chemotherapy options and negative patient outcomes. Food-derived molecules such as avocatin B (Avo B), a fatty-acid oxidation (FAO) inhibitor, are promising novel therapeutics. The roots of the Curcuma amada plants have been historically used in traditional medicine, but isolated bioactive compounds have seldom been studied. Here, we report that 2,4,6-trihydroxy-3,5-diprenyldihydrochalcone (M1), a bioactive from C. Amada, possesses novel anticancer activity. This in vitro study investigated the antileukemia properties of M1 and its effects on mitochondrial metabolism. In combination with Avo B, M1 synergistically reduced AML cell line viability and patient-derived clonogenic growth with no effect on normal peripheral blood stem cells. Mechanistically, M1 alone inhibited mitochondria complex I, while the M1/Avo B combination inhibited FAO by 60 %, a process essential to the synergy. These results identified a novel food-derived bioactive and its potential as a novel chemotherapeutic for AML.ntial as a novel chemotherapeutic for AML.)
• Maeda 2020 J Cell Mol Med  + (Acute myocardial infarction is a leading c … Acute myocardial infarction is a leading cause of death among single organ diseases. Despite successful reperfusion therapy, ischaemia reperfusion injury (IRI) can induce oxidative stress (OS), cardiomyocyte apoptosis, autophagy and release of inflammatory cytokines, resulting in increased infarct size. In IRI, mitochondrial dysfunction is a key factor, which involves the production of reactive oxygen species, activation of inflammatory signalling cascades or innate immune responses, and apoptosis. Therefore, intercellular mitochondrial transfer could be considered as a promising treatment strategy for ischaemic heart disease. However, low transfer efficiency is a challenge in clinical settings. We previously reported uptake of isolated exogenous mitochondria into cultured cells through co-incubation, mediated by macropinocytosis. Here, we report the use of transactivator of transcription dextran complexes (TAT-dextran) to enhance cellular uptake of exogenous mitochondria and improve the protective effect of mitochondrial replenishment in neonatal rat cardiomyocytes (NRCMs) against OS. TAT-dextran-modified mitochondria (TAT-Mito) showed a significantly higher level of cellular uptake. Mitochondrial transfer into NRCMs resulted in anti-apoptotic capability and prevented the suppression of oxidative phosphorylation in mitochondria after OS. Furthermore, TAT-Mito significantly reduced the apoptotic rates of cardiomyocytes after OS, compared to simple mitochondrial transfer. These results indicate the potential of mitochondrial replenishment therapy in OS-induced myocardial IRI.</br></br><small>© 2020 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.</small>ular Medicine and John Wiley & Sons Ltd.</small>)
• Roy 2016 Free Radic Biol Med  + (Acute myocardial infarction leads to an in … Acute myocardial infarction leads to an increase in oxidative stress and lipid peroxidation. 4(RS)-4-F4t-Neuroprostane (4-F4t-NeuroP) is a mediator produced by non-enzymatic free radical peroxidation of the cardioprotective polyunsaturated fatty acid, docosahexaenoic acid (DHA). In this study, we investigated whether intra-cardiac delivery of 4-F4t-NeuroP (0.03mg/kg) prior to occlusion (ischemia) prevents and protects rat myocardium from reperfusion damages. Using a rat model of ischemic-reperfusion (I/R), we showed that intra-cardiac infusion of 4-F4t-NeuroP significantly decreased infarct size following reperfusion (-27%) and also reduced ventricular arrhythmia score considerably during reperfusion (-41%). Most notably, 4-F4t-NeuroP decreased ventricular tachycardia and post-reperfusion lengthening of QT interval. The evaluation of the mitochondrial homeostasis indicates a limitation of mitochondrial swelling in response to Ca²⁺ by decreasing the mitochondrial permeability transition pore opening and increasing mitochondria membrane potential. On the other hand, mitochondrial respiration measured by oxygraphy, and mitochondrial ROS production measured with MitoSox red® were unchanged. We found decreased cytochrome ''c'' release and caspase 3 activity, indicating that 4-F4t-NeuroP prevented reperfusion damages and reduced apoptosis. In conclusion, 4-F4t-NeuroP derived from DHA was able to protect I/R cardiac injuries by regulating the mitochondrial homeostasis.</br></br>Copyright © 2016 Elsevier Inc. All rights reserved.. Copyright © 2016 Elsevier Inc. All rights reserved.)
• Ohsawa 2007 Nat Med  + (Acute oxidative stress induced by ischemia … Acute oxidative stress induced by ischemia-reperfusion or inflammation causes serious damage to tissues, and persistent oxidative stress is accepted as one of the causes of many common diseases including cancer. We show here that hydrogen (H₂) has potential as an antioxidant in preventive and therapeutic applications. We induced acute oxidative stress in cultured cells by three independent methods. H₂ selectively reduced the hydroxyl radical, the most cytotoxic of reactive oxygen species (ROS), and effectively protected cells; however, H₂ did not react with other ROS, which possess physiological roles. We used an acute rat model in which oxidative stress damage was induced in the brain by focal ischemia and reperfusion. The inhalation of H₂ gas markedly suppressed brain injury by buffering the effects of oxidative stress. Thus H₂ can be used as an effective antioxidant therapy; owing to its ability to rapidly diffuse across membranes, it can reach and react with cytotoxic ROS and thus protect against oxidative damage.across membranes, it can reach and react with cytotoxic ROS and thus protect against oxidative damage.)
• Mikami 2019 Can J Physiol Pharmacol  + (Acute physical exercise increases reactive … Acute physical exercise increases reactive oxygen species in skeletal muscle, leading to tissue damage and fatigue. Molecular hydrogen (H2) acts as a therapeutic antioxidant directly or indirectly by inducing antioxidative enzymes. Here, we examined the effects of drinking H2 water (H2-infused water) on psychometric fatigue and endurance capacity in a randomized, double-blind, placebo-controlled fashion. In Experiment 1, all participants drank only placebo water in the first cycle ergometer exercise session, and for comparison they drank either H2 water or placebo water 30 min before exercise in the second examination. In these healthy non-trained participants (''N'' = 99), psychometric fatigue judged by visual analogue scales was significantly decreased in the H2 group after mild exercise. When each group was divided into 2 subgroups, the subgroup with higher visual analogue scale values was more sensitive to the effect of H2. In Experiment 2, trained participants (''N'' = 60) were subjected to moderate exercise by cycle ergometer in a similar way as in Experiment 1, but exercise was performed 10 min after drinking H2 water. Endurance and fatigue were significantly improved in the H2 group as judged by maximal oxygen consumption and Borg's scale, respectively. Taken together, drinking H2 water just before exercise exhibited anti-fatigue and endurance effects.ibited anti-fatigue and endurance effects.)
• Hoppel 2015 Abstract MiP2015  + (Acute strenuous exercise is linked to seve … Acute strenuous exercise is linked to severe inflammatory responses [1,2], alterations of mitochondrial function of human skeletal muscle and increased oxidative stress [3]. Due to the invasive nature of muscle biopsies, minimally-invasive alternatives to study mitochondrial function in tissues such as blood cells are gaining significance. Mitochondrial function in human platelets and lymphocytes has been characterized in various disease states. Importantly, respiratory capacity of human PBMCs was linked to physical fitness [4], supporting the concept that mitochondrial function in human blood cells can be used as a systemic mitochondrial marker. In this study we investigated the influence of completion of an ultramarathon on mitochondrial respiration in human platelets.</br></br>After informed consent, 10 male recreational athletes (mean age: 39.9 yrs; BMI 24.9 kg2/m) who participated in a competition over 67 km and approximately 4,500 m ascent, were included in the study. Baseline (PRE) measurements were performed on the day before the competition and follow-up sampling was performed within 15 min after finishing the race (POST) by sampling whole blood. To address potential effects of recovery, a third time point was selected 24 h after finishing (REC). Evaluation of mitochondrial respiration was conducted in freshly purified human platelets by the use of six Oroboros Oxygraph-2k operating in parallel. ROUTINE respiration (R), Complex I-linked LEAK and OXPHOS capacity (CI), and CI&II-linked OXPHOS and ET capacity were determined in a single SUIT protocol. Additionally, neutrophils, monocytes and lymphocytes (inflammatory response), creatine kinase (CK; muscular damage) and plasma markers of oxidative damage and repair were quantified at baseline and after the race.</br></br>Absolute concentrations of all leukocyte subgroups and serum creatine kinase were changed significantly after the race. No significant changes were found in respiratory substrate control ratios CI/CI&II and CII/CI&II, neither when comparing PRE and POST, nor between POST and recovery. However, the ROUTINE coupling control ratio, R/E (ROUTINE respiration of intact cells, R, divided by uncoupler-stimulated electron transfer-pathway capacity, E) was increased significantly (+25,4% PRE vs. POST; +9,5% PRE vs. REC; ''p''<0.05), indicating the influence of massive physical strain and time of recovery on human platelet metabolism. We found a significant (''p''<0,05) relationship between BMI and CI/CI&II ratio, whereas age and training time per week were without significant effects on platelet metabolism.er week were without significant effects on platelet metabolism.)
• Datzmann 2019 J Neurosurg  + (Acute subdural hematoma (ASDH) is a leadin … Acute subdural hematoma (ASDH) is a leading entity in brain injury. Rodent models mostly lack standard intensive care, while large animal models frequently are only short term. Therefore, the authors developed a long-term, resuscitated porcine model of ASDH-induced brain injury and report their findings.</br></br>Anesthetized, mechanically ventilated, and instrumented pigs with human-like coagulation underwent subdural injection of 20 mL of autologous blood and subsequent observation for 54 hours. Continuous bilateral multimodal brain monitoring (intracranial pressure [ICP], cerebral perfusion pressure [CPP], partial pressure of oxygen in brain tissue [PbtO₂], and brain temperature) was combined with intermittent neurological assessment (veterinary modified Glasgow Coma Scale [MGCS]), microdialysis, and measurement of plasma protein S100β, GFAP, neuron-specific enolase [NSE], nitrite+nitrate, and isoprostanes. Fluid resuscitation and continuous intravenous norepinephrine were targeted to maintain CPP at pre-ASDH levels. Immediately postmortem, the brains were taken for macroscopic and histological evaluation, immunohistochemical analysis for nitrotyrosine formation, albumin extravasation, NADPH oxidase 2 (NOX2) and GFAP expression, and quantification of tissue mitochondrial respiration.</br></br>Nine of 11 pigs survived the complete observation period. While ICP significantly increased after ASDH induction, CPP, PbtO₂, and the MGCS score remained unaffected. Blood S100β levels significantly fell over time, whereas GFAP, NSE, nitrite+nitrate, and isoprostane concentrations were unaltered. Immunohistochemistry showed nitrotyrosine formation, albumin extravasation, NOX2 expression, fibrillary astrogliosis, and microglial activation.</br></br>The authors describe a clinically relevant, long-term, resuscitated porcine model of ASDH-induced brain injury. Despite the morphological injury, maintaining CPP and PbtO₂ prevented serious neurological dysfunction. This model is suitable for studying therapeutic interventions during hemorrhage-induced acute brain injury with standard brain-targeted intensive care.rrhage-induced acute brain injury with standard brain-targeted intensive care.)
• Krumschnabel 2004 Aquat Toxicol  + (Acute toxic effects of hexavalent chromium … Acute toxic effects of hexavalent chromium [Cr(VI)], a widely recognised carcinogenic, mutagenic and redox active metal, were investigated in isolated hepatocytes of goldfish (Carassius auratus). Exposure to 250 microM Cr(VI) induced a significant decrease of cell viability from 94% in controls to 88% and 84% after 30 min and 4 h of exposure, respectively. Cr-toxicity was associated with a concentration-dependent stimulation of the formation of reactive oxygen species (ROS). As one potential source of ROS formation we identified the lysosomal Fe(2+) pool, since the ferric ion chelator deferoxamin inhibited ROS formation by approximately 15%. Lysosomal membranes remained nevertheless intact during Cr-exposure, as determined from neutral red retention in this compartment. Another significant source of ROS appear to be the mitochondria, where a presumably uncoupled increase of respiration by 20-30% was triggered by the metal. Inhibition of mitochondrial respiration by cyanide caused an approximately 40% decrease of Cr-induced ROS-formation, whereas the uncoupling agent carbonyl cyanide m-chlorophenyl hydrazine was without effect. Cellular Ca(2+) homeostasis was not disturbed by Cr(VI) and thus played no role in this scenario. Overall, our data show that Cr(VI) is acutely toxic to goldfish hepatocytes, and its toxicity is associated with the induction of radical stress, presumably involving lysosomes and mitochondria as important sources of ROS formation.ria as important sources of ROS formation.)
• Isola 2022 Abstract Bioblast  + (Acutely exposure to low oxygen concentrati … Acutely exposure to low oxygen concentrations, impairs the capability to perform muscular workout. On the other hand, repeated and prolonged exposure to low PO2 may improve physical performance due to a progressive adaptation of the body. This is mainly due to enhanced hemoglobin and red blood cells content, and decreased sympathetic autonomic nervous system input. These changes were evaluated in a number of chronic hypoxia studies [1-2], whereas acute hypoxia outcomes are still unknown.</br></br>This study investigates on acute hypoxia and normoxia impact on cardiac and brain mitochondrial bioenergetics and the possible occurrence of different gender responses.</br></br>We used male and female Wistar rats that had been trained for 5 weeks, 1h/day, on a treadmill set at 35 cm/s. The day of the experiment they were allowed to run on the treadmill for 30 minutes in hypoxia (at the same oxygen concentration of an altitude of 4000 mt.) or in normoxia. After euthanasia, we removed the brain and the heart and isolated brain mitochondria, subsarcolemmal (SSM) and interfibrillar (IFM) heart mitochondria [3]. Mitochondrial bioenergetics was assessed by Clark-type electrode, testing for oxidative phosphorylation (OXPHOS): complex I (glutamate plus malate), complex II (rotenone plus succinate), complex III (rotenone plus durohydroquinone), complex IV (rotenone plus tetramethyl-p-phenylenediamine and ascorbate), Palmitoyl CoA as lipid substrate and adding at the end of the assay dinitrophenol (DNP) to test uncoupled respiration with these substrates.</br></br>After acute hypoxia, brain male mitochondria showed an increase of uncoupled respiration at complex II and IV, whereas female mitochondria displayed no significant difference compared to controls.</br></br>In heart male IFM mitochondria, following acute hypoxia, ADP/O decreased at complex I and II, compared with controls. Furthermore, in the same complexes data showed an increase of respiratory control ratio, but only complex I resulted statistically significant. These data suggest that hypoxia induced a mild uncoupling of IFM.</br></br>Among female heart mitochondria, SSM only showed a decrease in state 3 of complex II after acute hypoxia.</br></br>In conclusion, in both genders cardiac and brain mitochondrial bioenergetics change after athletic training in acute hypoxia.</br></br>It seems that in female cardiac mitochondria hypoxia induced an impairment of complex II activity, while in male heart mitochondria the result need further investigation as it could be linked to a reported increased activity of ATPase under hypoxia [4] or a defective OXPHOS with a possible enhanced ROS production.</br></br>In male brain mitochondria the increased of uncoupled respiration might be linked to a better efficiency of electron transfer system (ETS). Future studies will need to verify these results.</br><small></br># Horscroft JA, Kotwica AO, Laner V, West JA, Hennis PJ, Levett DZH, Howard DJ, Fernandez BO, Burgess SL, Ament Z, Gilbert-Kawai ET, Vercueil A, Landis BD, Mitchell K, Mythen MG, Branco C, Johnson RS, Feelisch M, Montgomery HE, Griffin JL, Grocott MPW, Gnaiger E, Martin DS, Murray AJ (2017) Metabolic basis to Sherpa altitude adaptation. https://doi.org/10.1073/pnas.1700527114</br># Levett DZ, Radford EJ, Menassa DA, Graber EF, Morash AJ, Hoppeler H, Clarke K, Martin DS, Ferguson-Smith AC, Montgomery HE, Grocott MP, Murray AJ; Caudwell Xtreme Everest Research Group (2012) Acclimatization of skeletal muscle mitochondria to high-altitude hypoxia during an ascent of Everest. https://doi.org/10.1096/fj.11-197772</br># Palmer JW, Tandler B, Hoppel CL (1977) Biochemical properties of subsarcolemmal and interfibrillar mitochondria isolated from rat cardiac muscle. https://www.jbc.org/article/S0021-9258(19)75283-1/pdf</br># Kioka H, Kato H, Fujikawa M, Tsukamoto O, Suzuki T, Imamura H, Nakano A, Higo S, Yamazaki S, Matsuzaki T, Takafuji K, Asanuma H, Asakura M, Minamino T, Shintani Y, Yoshida M, Noji H, Kitakaze M, Komuro I, Asano Y, Takashima S (2014) Evaluation of intramitochondrial ATP levels identifies G0/G1 switch gene 2 as a positive regulator of oxidative phosphorylation. https://doi.org/10.1073/pnas.1318547111</br></small>https://doi.org/10.1073/pnas.1318547111 </small>)

• Fisher-Wellman 2019 Cell Rep  + (Acyl CoA metabolites derived from the cata … Acyl CoA metabolites derived from the catabolism of carbon fuels can react with lysine residues of mitochondrial proteins, giving rise to a large family of post-translational modifications (PTMs). Mass spectrometry-based detection of thousands of acyl-PTMs scattered throughout the proteome has established a strong link between mitochondrial hyperacylation and cardiometabolic diseases; however, the functional consequences of these modifications remain uncertain. Here, we use a comprehensive respiratory diagnostics platform to evaluate three disparate models of mitochondrial hyperacylation in the mouse heart caused by genetic deletion of malonyl CoA decarboxylase (MCD), SIRT5 demalonylase and desuccinylase, or SIRT3 deacetylase. In each case, elevated acylation is accompanied by marginal respiratory phenotypes. Of the >60 mitochondrial energy fluxes evaluated, the only outcome consistently observed across models is a ∼15% decrease in ATP synthase activity. In sum, the findings suggest that the vast majority of mitochondrial acyl PTMs occur as stochastic events that minimally affect mitochondrial bioenergetics.</br></br><small>Copyright © 2019 The Author(s). Published by Elsevier Inc. All rights reserved.</small>ished by Elsevier Inc. All rights reserved.</small>)
• Rajkumar 2018 Metabolism  + (Acyl-CoA Synthetase Long Chain 5 (ACSL5) g … Acyl-CoA Synthetase Long Chain 5 (ACSL5) gene's rs2419621 T/C polymorphism was associated with ''ACSL5'' mRNA expression and response to lifestyle interventions. However, the mechanistic understanding of the increased response in T allele carriers is lacking. Study objectives were to investigate the effect of rs2419621 genotype and ACSL5 human protein isoforms on fatty acid oxidation and respiration.</br></br>Human ACSL5 overexpression in C2C12 mouse myoblasts was conducted to measure ¹⁴C palmitic acid oxidation and protein isoform localization ''in vitro''. ¹⁴C palmitic acid oxidation studies and Western blot analysis of ACSL5 proteins were carried out in ''rectus abdominis'' primary myotubes from 5 rs2419621 T allele carriers and 4 non-carriers. In addition, mitochondrial high-resolution respirometry was conducted on ''vastus lateralis'' muscle biopsies from 4 rs2419621 T allele carriers and 4 non-carriers. Multiple linear regression analysis was conducted to test the association between rs2419621 genotype and respiratory quotient related pre- and post-lifestyle intervention measurements in postmenopausal women with overweight or obesity.</br></br>In comparison to rs2419621 non-carriers, T allele carriers displayed higher levels of i) 683aa ACSL5 isoform, localized mainly in the mitochondria, playing a greater role in fatty acid oxidation in comparison to the 739aa protein isoform ii) ''in vitro'' CO₂ production in ''rectus abdominis'' primary myotubes iii) ''in vivo'' fatty acid oxidation and lower carbohydrate oxidation post-intervention iv) ''ex vivo'' complex I and II tissue respiration in ''vastus lateralis'' muscle.</br></br>These results support the conclusion that rs2419621 T allele carriers, are more responsive to lifestyle interventions partly due to an increase in the short ACSL5 protein isoform, increasing cellular, tissue and whole-body fatty acid utilization. With the increasing effort to develop personalized medicine to combat obesity, our findings provide additional insight into genotypes that can significantly affect whole body metabolism and response to lifestyle interventions.</br></br>Copyright © 2018 Elsevier Inc. All rights reserved. lifestyle interventions. Copyright © 2018 Elsevier Inc. All rights reserved.)
• Dambrova 2022 Abstract Bioblast  + (Acylcarnitines are esters of L-carnitine t … Acylcarnitines are esters of L-carnitine that emerge from the energy metabolism pathways of fatty acids in mitochondria and peroxisomes [1]. Depending on the length of the acyl chain, acylcarnitines can be grouped as short-, medium-, long- and very long-chain acylcarnitines. Metabolomic profiling assays that investigate disease and nutrition states often include measurements of different acylcarnitines. This has resulted in increased interest regarding the consequences of elevated/decreased levels of plasma acylcarnitine concentrations and the mechanisms associated with these changes.</br></br>Altered acylcarnitine metabolome is characteristic for certain inborn errors of fatty acid metabolism, as well as cardiovascular, metabolic and neurological diseases, and some forms of cancer. Acylcarnitines are considered as biomarkers for such diseases and pathological conditions as insulin resistance, heart failure and fatty acid oxidation metabolism-related inherited diseases. Long-chain acylcarnitines accumulate under conditions of insufficient mitochondrial functionality and can reach tissue levels that can affect enzyme and ion channel activities and impact energy metabolism pathways and cellular homeostasis. These detrimental processes directly impact mitochondrial physiology and can exaggerate arrhythmia, insulin insufficiency, neurodegenerative and neuropsychiatric conditions.</br></br>Dietary and pharmacological means can be used to regulate synthesis and transport pathways of acylcarnitines and thus counteract the detrimental effects of their accumulation or reverse deficits. The most abundant acylcarnitines, acetylcarnitine and propionylcarnitine, are used as food supplements to tackle neurological and cardiovascular conditions.</br></br>Better understanding of biochemical and molecular mechanisms behind increased/decreased acylcarnitine levels and their physiological and pathological roles forms basis for therapeutic target selection and preclinical drug discovery in future and also explains off-target effects of some clinically used drugs.</br><small></br># Dambrova M et al (2022) Acylcarnitines: nomenclature, biomarkers, therapeutic potential, drug targets and clinical trials. Pharmacol Rev 74:1-50 (in press).</br></small>ials. Pharmacol Rev 74:1-50 (in press). </small>)
• Dambrova 2022 Pharmacol Rev  + (Acylcarnitines are fatty acid metabolites … Acylcarnitines are fatty acid metabolites that play important roles in many cellular energy metabolism pathways. They have historically been used as important diagnostic markers for inborn errors of fatty acid oxidation and are being intensively studied as markers of energy metabolism, deficits in mitochondrial and peroxisomal β -oxidation activity, insulin resistance, and physical activity. Acylcarnitines are increasingly being identified as important indicators in metabolic studies of many diseases, including metabolic disorders, cardiovascular diseases, diabetes, depression, neurologic disorders, and certain cancers. The US Food and Drug Administration-approved drug L-carnitine, along with short-chain acylcarnitines (acetylcarnitine and propionylcarnitine), is now widely used as a dietary supplement. In light of their growing importance, we have undertaken an extensive review of acylcarnitines and provided a detailed description of their identity, nomenclature, classification, biochemistry, pathophysiology, supplementary use, potential drug targets, and clinical trials. We also summarize these updates in the Human Metabolome Database, which now includes information on the structures, chemical formulae, chemical/spectral properties, descriptions, and pathways for 1240 acylcarnitines. This work lays a solid foundation for identifying, characterizing, and understanding acylcarnitines in human biosamples. We also discuss the emerging opportunities for using acylcarnitines as biomarkers and as dietary interventions or supplements for many wide-ranging indications. The opportunity to identify new drug targets involved in controlling acylcarnitine levels is also discussed. SIGNIFICANCE STATEMENT: This review provides a comprehensive overview of acylcarnitines, including their nomenclature, structure and biochemistry, and use as disease biomarkers and pharmaceutical agents. We present updated information contained in the Human Metabolome Database website as well as substantial mapping of the known biochemical pathways associated with acylcarnitines, thereby providing a strong foundation for further clarification of their physiological roles.larification of their physiological roles.)
• Ojuka 2015 Abstract MiPschool Cape Town 2015  + (Acylcarnitines when converted to acyl –CoA … Acylcarnitines when converted to acyl –CoA in the mitochondrial matrix</br>are a major source of ATP after oxidation. Their oxidation process,</br>termed β-oxidation, runs through four sequential enzymes namely:</br>acyl-CoA dehydrogenase, 2-enoyl-CoA hydratase, L-3-hydroxyacyl-</br>CoA dehydrogenase, and 3-ketoacyl-CoA thiolase [1]. Acyl-CoA</br>dehydrogenases transfer single electrons to electron transferring</br>flavoprotein (ETF) [2] which donates electrons directly to the ubiquinone</br>(Q) pool in the mitochondrial inner membrane. Hydroxyacyl-CoA</br>dehydrogenase transfers electrons to NAD+ and the reduced NADH</br>is oxidized by complex I. The end product of β-oxidation, acetyl-CoA,</br>condenses with oxaloacetate to form citrate which is oxidized by the</br>Krebs cycle. Oxidation of fatty acylcarnitines therefore contributes to</br>OXPHOS and ATP production by donating electrons at various points of</br>the electron transfer-pathway.</br></br>To assess oxidation of acylcarnitines under various experimental</br>conditions, scientist often measure oxygen consumption in isolated</br>mitochondria, permeabilized cells, or tissues in an oxygraph using</br>a variety of substrate combinations including palmatoylcarnitine in</br>combination with carnitine or malate. Use of palmatoylcarnitine alone</br>yields low oxygen flux rates and is not responsive to ADP, oligomycin</br>or uncouplers. These observations are attributed to a low CoA/</br>palmatoylCoA ratio which inactivates 3-ketoacyl-CoA thiolase and slows</br>down or stops β-oxidation. Use of palmatoylcarnitine in combination with</br>carnitine or malate increase State 2 respiration (oxygen consumption</br>with substrate without addition of ADP) and are responsive to ADP,</br>oligomycin and uncouples -- but to different degrees. The increase in</br>oxygen flux rates after ADP or uncoupler addition is explained by the</br>increased CoA/palmatoylCoA ratio which favours β-oxidation. The</br>differences in response to ADP and uncoupler is probably due the fact</br>that oxidation of palmitoylcarnitine in the presence of carnitine transfers</br>electrons to the ETS without involving the Krebs cycle whereas oxidation</br>of palmitoylcarnitine and malate does [3].of palmitoylcarnitine and malate does [3].)
• Kang 2017 Mol Cell  + (Acylglycerol kinase (AGK) is a mitochondri … Acylglycerol kinase (AGK) is a mitochondrial lipid kinase that catalyzes the phosphorylation of monoacylglycerol and diacylglycerol to lysophosphatidic acid and phosphatidic acid, respectively. Mutations in AGK cause Sengers syndrome, which is characterized by congenital cataracts, hypertrophic cardiomyopathy, skeletal myopathy, exercise intolerance, and lactic acidosis. Here we identified AGK as a subunit of the mitochondrial TIM22 protein import complex. We show that AGK functions in a kinase-independent manner to maintain the integrity of the TIM22 complex, where it facilitates the import and assembly of mitochondrial carrier proteins. Mitochondria isolated from Sengers syndrome patient cells and tissues show a destabilized TIM22 complex and defects in the biogenesis of carrier substrates. Consistent with this phenotype, we observe perturbations in the tricarboxylic acid (TCA) cycle in cells lacking AGK. Our identification of AGK as a bona fide subunit of TIM22 provides an exciting and unexpected link between mitochondrial protein import and Sengers syndrome.drial protein import and Sengers syndrome.)
• Gak 2015 Biochim Biophys Acta  + (Adaptability to stress is a fundamental pr … Adaptability to stress is a fundamental prerequisite for survival. Mitochondria are a key component of the stress response in all cells. For steroid-hormones-producing cells, including also Leydig cells of testes, the mitochondria are a key control point for the steroid biosynthesis and regulation. However, the mitochondrial biogenesis in steroidogenic cells has never been explored. Here we show that increased mitochondrial biogenesis is the adaptive response of testosterone-producing Leydig cells from stressed rats. All markers of mitochondrial biogenesis together with transcription factors and related kinases are up-regulated in Leydig cells from rats exposed to repeated psychophysical stress. This is followed with increased mitochondrial mass. The expression of PGC1, master regulator of mitochondrial biogenesis and integrator of environmental signals, is stimulated by cAMP-PRKA, cGMP, and β-adrenergic receptors. Accordingly, stress-triggered mitochondrial biogenesis represents an adaptive mechanism and does not only correlate with but also is an essential for testosterone production, being both events depend on the same regulators. Here we propose that all events induced by acute stress, the most common stress in human society, provoke adaptive response of testosterone-producing Leydig cells and activate PGC1, a protein required to make new mitochondria but also protector against the oxidative damage. Given the importance of mitochondria for steroid hormones production and stress response, as well as the role of steroid hormones in stress response and metabolic syndrome, we anticipate our result to be a starting point for more investigations since stress is a constant factor in life and has become one of the most significant health problems in modern societies.</br></br>Copyright © 2015 Elsevier B.V. All rights reserved. © 2015 Elsevier B.V. All rights reserved.)
• Mantilla 2017 PLOS Pathog  + (Adaptation to different nutritional enviro … Adaptation to different nutritional environments is essential for life cycle completion by all ''Trypanosoma brucei'' sub-species. In the tsetse fly vector, L-proline is among the most abundant amino acids and is mainly used by the fly for lactation and to fuel flight muscle. The procyclic (insect) stage of ''T. b. brucei'' uses L-proline as its main carbon source, relying on an efficient catabolic pathway to convert it to glutamate, and then to succinate, acetate and alanine as the main secreted end products. Here we investigated the essentiality of an undisrupted proline catabolic pathway in ''T. b. brucei'' by studying mitochondrial Δ1-pyrroline-5-carboxylate dehydrogenase (TbP5CDH), which catalyzes the irreversible conversion of gamma-glutamate semialdehyde (γGS) into L-glutamate and NADH. In addition, we provided evidence for the absence of a functional proline biosynthetic pathway. TbP5CDH expression is developmentally regulated in the insect stages of the parasite, but absent in bloodstream forms grown ''in vitro''. RNAi down-regulation of TbP5CDH severely affected the growth of procyclic trypanosomes ''in vitro'' in the absence of glucose, and altered the metabolic flux when proline was the sole carbon source. Furthermore, TbP5CDH knocked-down cells exhibited alterations in the mitochondrial inner membrane potential (ΔΨm), respiratory control ratio and ATP production. Also, changes in the proline-glutamate oxidative capacity slightly affected the surface expression of the major surface glycoprotein EP-procyclin. In the tsetse, TbP5CDH knocked-down cells were impaired and thus unable to colonize the fly's midgut, probably due to the lack of glucose between bloodmeals. Altogether, our data show that the regulated expression of the proline metabolism pathway in ''T. b. brucei'' allows this parasite to adapt to the nutritional environment of the tsetse midgut.ritional environment of the tsetse midgut.)
• Ter Veld 2005 FEBS J  + (Adaptations of the kinetic properties of m … Adaptations of the kinetic properties of mitochondria in striated muscle lacking cytosolic (M) and/or mitochondrial (mt) creatine kinase (CK) isoforms in comparison to wild-type (WT) were investigated ''in vitro''. Intact mitochondria were isolated from heart and gastrocnemius muscle of WT and single- and double CK-knock-out mice strains (cytosolic (M-CK^–/–), mitochondrial (mt-CK^–/–) and double knock-out (mtM-CK^–/–), respectively). Maximal ADP-stimulated oxygen consumption flux (State3 Vmax; nmol O2·mg mitochondrial protein^–1·min^–1) and ADP affinity (inline image; µm) were determined by respirometry. State 3 Vmax and inline image of M-CK^–/– and mtIM-CK^–/– gastrocnemius mitochondria were twofold higher than those of WT, but were unchanged for mt-CK^–/–. For mutant cardiac mitochondria, only the inline image of mitochondria isolated from the mtM-CK^–/– phenotype was different (i.e. twofold higher) than that of WT. The implications of these adaptations for striated muscle function were explored by constructing force-flow relations of skeletal muscle respiration. It was found that the identified shift in affinity towards higher ADP concentrations in mtM-CK^–/– muscle genotypes may contribute to linear mitochondrial control of the reduced cytosolic ATP free energy potentials in these phenotypes.lt;sup>–/–</sup> muscle genotypes may contribute to linear mitochondrial control of the reduced cytosolic ATP free energy potentials in these phenotypes.)
• Dogan 2014 Cell Metab  + (Adaptive stress responses activated upon m … Adaptive stress responses activated upon mitochondrial dysfunction are assumed to arise in order to counteract respiratory chain deficiency. Here, we demonstrate that loss of DARS2 (mitochondrial aspartyl-tRNA synthetase) leads to the activation of various stress responses in a tissue-specific manner independently of respiratory chain deficiency. DARS2 depletion in heart and skeletal muscle leads to the severe deregulation of mitochondrial protein synthesis followed by a strong respiratory chain deficit in both tissues, yet the activation of adaptive responses is observed predominantly in cardiomyocytes. We show that the impairment of mitochondrial proteostasis in the heart activates the expression of mitokine FGF21, which acts as a signal for cell-autonomous and systemic metabolic changes. Conversely, skeletal muscle has an intrinsic mechanism relying on the slow turnover of mitochondrial transcripts and higher proteostatic buffering capacity. Our results show that mitochondrial dysfunction is sensed independently of respiratory chain deficiency, questioning the current view on the role of stress responses in mitochondrial diseases.</br></br><small>Copyright © 2014 Elsevier Inc. All rights reserved.</small> 2014 Elsevier Inc. All rights reserved.</small>)
• Puigserver 1998 Cell  + (Adaptive thermogenesis is an important com … Adaptive thermogenesis is an important component of energy homeostasis and a metabolic defense against obesity. We have cloned a novel transcriptional coactivator of nuclear receptors, termed PGC-1, from a brown fat cDNA library. PGC-1 mRNA expression is dramatically elevated upon cold exposure of mice in both brown fat and skeletal muscle, key thermogenic tissues. PGC-1 greatly increases the transcriptional activity of PPARgamma and the thyroid hormone receptor on the uncoupling protein (UCP-1) promoter. Ectopic expression of PGC-1 in white adipose cells activates expression of UCP-1 and key mitochondrial enzymes of the respiratory chain, and increases the cellular content of mitochondrial DNA. These results indicate that PGC-1 plays a key role in linking nuclear receptors to the transcriptional program of adaptive thermogenesis.ptional program of adaptive thermogenesis.)
• Ransy 2020 Int J Mol Sci  + (Addition of hydrogen peroxide (H<sub> … Addition of hydrogen peroxide (H₂O₂) is a method commonly used to trigger cellular oxidative stress. However, the doses used (often hundreds of micromolar) are disproportionally high with regard to physiological oxygen concentration (low micromolar). In this study using polarographic measurement of oxygen concentration in cellular suspensions we show that H₂O₂ addition results in O₂ release as expected from catalase reaction. This reaction is fast enough to, within seconds, decrease drastically H₂O₂ concentration and to annihilate it within a few minutes. Firstly, this is likely to explain why recording of oxidative damage requires the high concentrations found in the literature. Secondly, it illustrates the potency of intracellular antioxidant (H₂O₂) defense. Thirdly, it complicates the interpretation of experiments as subsequent observations might result from high/transient H2O2 exposure and/or from the diverse possible consequences of the O₂ release. as subsequent observations might result from high/transient H2O2 exposure and/or from the diverse possible consequences of the O₂ release.)
• Ratajczak 2019 Anal Bioanal Chem  + (Adenosine triphosphate (ATP) is the main e … Adenosine triphosphate (ATP) is the main energy source in cells and an important biomolecule participating in cellular reactions in living organisms. Since the ATP level changes dynamically reflecting the development of a debilitating disease or carcinogenesis, we have focused in this work on monitoring of the oligomycin (OMC)-modulated ATP synthase inhibition using a fluorescent-switching DNA aptamer designed for the detection of ATP (Apt(ATP)), as the model for studies of dynamic ATP level variation. The behavior of the ATP aptamer has been characterized using fluorescence spectroscopy. The Intramolecular fluorescence resonance energy transfer (iFRET) operates in the proposed aptamer from the FAM dye moiety to guanines of the aptamer G-quadruplex when the target ATP is present and binds to the aptamer changing its conformation. The iFRET process enables the detection of ATP down to the limit of detection, LOD = 17 μM, without resorting to any extra chemi-amplification schemes. The selectivity coefficients for relevant interferent triphosphates (UTP, GTP, and CTP) are low for the same concentration as that of ATP. We have demonstrated an efficient transfection of intact cells and OMC-treated SW480 colon cancer cells with Apt(ATP), using microscopic imaging, iFRET measurements, and cell viability testing with MTT method. The applicability of the switching DNA aptamer for the analysis of real samples, obtained by lysis of SW480 cells, was also tested. The proposed Apt(ATP) may be considered as a viable candidate for utilization in measurements of dynamic ATP level modulation in cells in different stages of cancer development and testing of new drugs in pharmacological studies.g of new drugs in pharmacological studies.)
• Baldini 2021 Life Sci  + (Adipocyte hypertrophy is the main cause of … Adipocyte hypertrophy is the main cause of obesity. A deeper understanding of the molecular mechanisms regulating adipocyte dysfunction may help to plan strategies to treat/prevent obesity and its metabolic complications. Here, we investigated ''in vitro'' the molecular alterations associated with early adipocyte hypertrophy, focusing on mitochondrial dysfunction.</br></br>As model of adipocyte hypertrophy, we employed 3T3-L1 preadipocytes firstly differentiated into mature adipocytes, then cultured with long-chain fatty acids. As a function of differentiation and hypertrophy, we assessed triglyceride content, lipid droplet size, radical homeostasis by spectrophotometry and microscopy, as well as the expression of PPARγ, adiponectin and metallothioneins. Mitochondrial status was investigated by electron microscopy, Oxygraph-2k (O2K) high-resolution respirometry, fluorimetry and western blot.</br></br>Compared to mature adipocytes, hypertrophic adipocytes showed increased triglyceride accumulation and lipid peroxidation, larger or unique lipid droplet, up-regulated expression of PPARγ, adiponectin and metallothioneins. At mitochondrial level, early-hypertrophic adipocytes exhibited: (i) impaired mitochondrial oxygen consumption with parallel reduction in the mitochondrial complexes; (ii) no changes in citrate synthase and HSP60 expression, and in the inner mitochondrial membrane polarization; (iii) no stimulation of mitochondrial fatty acid oxidation. Our findings indicate that the content, integrity, and catabolic activity of mitochondria were rather unchanged in early hypertrophic adipocytes, while oxygen consumption and oxidant production were altered.</br></br>In the model of early adipocyte hypertrophy exacerbated oxidative stress and impaired mitochondrial respiration were observed, likely depending on reduction in the mitochondrial complexes, without changes in mitochondrial mass and integrity.anges in mitochondrial mass and integrity.)
• Bikman 2022 Eur J Clin Nutr  + (Adipocyte mitochondrial respiration may in … Adipocyte mitochondrial respiration may influence metabolic fuel partitioning into oxidation versus storage, with implications for whole-body energy expenditure. Although insulin has been shown to influence mitochondrial respiration, the effects of dietary macronutrient composition have not been well characterized. The aim of this exploratory study was to test the hypothesis that a high-carbohydrate diet lowers the oxygen flux of adipocyte mitochondria ''ex vivo''. Among participants in a randomized-controlled weight-loss maintenance feeding trial, those consuming a high-carbohydrate diet (60% carbohydrate as a proportion of total energy, n = 10) had lower rates of maximal adipose tissue mitochondrial respiration than those consuming a moderate-carbohydrate diet (40%, n = 8, p = 0.039) or a low-carbohydrate diet (20%, n = 9, p = 0.005) after 10 to 15 weeks. This preliminary finding may provide a mechanism for postulated calorie-independent effects of dietary composition on energy expenditure and fat deposition, potentially through the actions of insulin on fuel partitioning.e actions of insulin on fuel partitioning.)
• Llobet 2015 Dis Model Mech  + (Adipogenesis is accompanied by differentia … Adipogenesis is accompanied by differentiation of adipose tissue-derived stem cells to adipocytes. As a part of this differentiation, biogenesis of the oxidative phosphorylation system occurs. Many chemical compounds used in medicine, agriculture, or other human activities, affect the oxidative phosphorylation function. Therefore, these xenobiotics could alter adipogenesis. We have analyzed the effects on adipocyte differentiation of some xenobiotics that act on the oxidative phosphorylation system. The tested concentrations have been previously reported in human blood. Our results show that pharmaceutical drugs that decrease mitochondrial DNA replication, such as nucleoside reverse transcriptase inhibitors, or inhibitors of mitochondrial protein synthesis, like ribosomal antibiotics, diminish adipocyte differentiation and leptin secretion. On the other hand, the environmental chemical pollutant tributyltin chloride, inhibiting the ATP synthase of the oxidative phosphorylation system, can promote adipocyte differentiation and leptin secretion, leading to obesity and metabolic syndrome as the obesogen hypothesis postulates.ome as the obesogen hypothesis postulates.)
• Shi 2023 Redox Biol  + (Adipose plasticity is critical for metabol … Adipose plasticity is critical for metabolic homeostasis. Adipocyte transdifferentiation plays an important role in adipose plasticity, but the molecular mechanism of transdifferentiation remains incompletely understood. Here we show that the transcription factor FoxO1 regulates adipose transdifferentiation by mediating Tgfβ1 signaling pathway. Tgfβ1 treatment induced whitening phenotype in beige adipocytes, reducing UCP1 and mitochondrial capacity and enlarging lipid droplets. Deletion of adipose FoxO1 (adO1KO) dampened Tgfβ1 signaling by downregulating Tgfbr2 and Smad3 and induced browning of adipose tissue in mice, increasing UCP1 and mitochondrial content and activating metabolic pathways. Silencing FoxO1 also abolished the whitening effect of Tgfβ1 on beige adipocytes. The adO1KO mice exhibited a significantly higher energy expenditure, lower fat mass, and smaller adipocytes than the control mice. The browning phenotype in adO1KO mice was associated with an increased iron content in adipose tissue, concurrent with upregulation of proteins that facilitate iron uptake (DMT1 and TfR1) and iron import into mitochondria (Mfrn1). Analysis of hepatic and serum iron along with hepatic iron-regulatory proteins (ferritin and ferroportin) in the adO1KO mice revealed an adipose tissue-liver crosstalk that meets the increased iron requirement for adipose browning. The FoxO1-Tgfβ1 signaling cascade also underlay adipose browning induced by β3-AR agonist CL316243. Our study provides the first evidence of a FoxO1-Tgfβ1 axis in the regulation of adipose browning-whitening transdifferentiation and iron influx, which sheds light on the compromised adipose plasticity in conditions of dysregulated FoxO1 and Tgfβ1 signaling.of dysregulated FoxO1 and Tgfβ1 signaling.)
• Lefranc 2019 Hypertension  + (Adipose tissue (AT) senescence and mitocho … Adipose tissue (AT) senescence and mitochondrial dysfunction are associated with obesity. Studies in obese patients and animals demonstrate that the MR (mineralocorticoid receptor) contributes to obesity-associated cardiovascular complications through its specific role in AT. However, underlying mechanisms remain unclear. This study aims to elucidate whether MR regulates mitochondrial function in obesity, resulting in AT premature aging and vascular dysfunction. Obese (db/db) and lean (db/+) mice were treated with an MR antagonist or a specific mitochondria-targeted antioxidant. Mitochondrial and vascular functions were determined by respirometry and myography, respectively. Molecular mechanisms were probed by Western immunoblotting and real-time polymerase chain reaction in visceral AT and arteries and focused on senescence markers and redox-sensitive pathways. db/db mice displayed AT senescence with activation of the p53-p21 pathway and decreased SIRT (sirtuin) levels, as well as mitochondrial dysfunction. Furthermore, the beneficial anticontractile effects of perivascular AT were lost in db/db via ROCK (Rho kinase) activation. MR blockade prevented these effects. Thus, MR activation in obesity induces mitochondrial dysfunction and AT senescence and dysfunction, which consequently increases vascular contractility. In conclusion, our study identifies novel mechanistic insights involving MR, adipose mitochondria, and vascular function that may be of importance to develop new therapeutic strategies to limit obesity-associated cardiovascular complications.y-associated cardiovascular complications.)
• Dela MiP2010  + (Adipose tissue exerts important endocrine … Adipose tissue exerts important endocrine and metabolic functions in health and disease. Yet the bioenergetics of this tissue is not characterized in humans and possible regional differences are not elucidated. Using high-resolution respirometry, mitochondrial respiration was quantified in human abdominal subcutaneous and intra-abdominal, visceral (omentum majus) adipose tissue from biopsies obtained in twenty obese patients undergoing bariatric surgery. [[mtDNA]] and gDNA were determined by PCR technique for estimation of mitochondrial density. Adipose tissue samples were permeabilized and respirometric measurements were performed in duplicate at 37 °C. Substrates [glutamate(G) + malate(M) + octanoyl carnitine(Oct) + succinate(S)] were added sequentially to provide electrons to Complexes CI + CII. ADP (D) for [[State 3]] respiration was added after GM. Non-coupled respiration was measured after addition of FCCP. Visceral fat contained more mitochondria per mg tissue than subcutaneous fat, but the cells were smaller. Robust, stable oxygen fluxes were found in both tissues, and coupled State 3 (GMOctSD) and non-coupled respiration were significantly (''P''<0.05) higher in visceral (0.95±0.05 and 1.15±0.06 pmol O2∙s^-1∙mg^-1, respectively) compared with subcutaneous (0.76±0.04 and 0.98±0.05 pmol O2∙s^-1∙mg^-1, respectively) adipose tissue. Expressed per mtDNA, visceral adipose tissue had significantly (''P''<0.05) lower mitochondrial respiration. Substrate control ratios were higher and uncoupling control ratio lower (''P''<0.05) in visceral compared with subcutaneous adipose tissue. </br></br>Visceral fat is bioenergetically more active and more sensitive to mitochondrial substrate supply than subcutaneous fat. [[OXPHOS]] has a higher relative activity in visceral compared with subcutaneous adipose tissue.s a higher relative activity in visceral compared with subcutaneous adipose tissue.)
• Kraunsoee 2010 J Physiol  + (Adipose tissue exerts important endocrine … Adipose tissue exerts important endocrine and metabolic functions in health and disease. Yet the bioenergetics of this tissue is not characterized in humans and possible regional differences are not elucidated. Using high-resolution respirometry, mitochondrial respiration was quantified in human abdominal subcutaneous and intra-abdominal visceral (omentum majus) adipose tissue from biopsies obtained in 20 obese patients undergoing bariatric surgery. Mitochondrial DNA (mtDNA) and genomic DNA (gDNA) were determined by the PCR technique for estimation of mitochondrial density. Adipose tissue samples were permeabilized and respirometric measurements were performed in duplicate at 37 °C. Substrates (glutamate (G) + malate (M) + octanoyl carnitine (Oct) + succinate (S)) were added sequentially to provide electrons to Complex I+II. ADP (_D) for State 3 respiration was added after GM. Non-coupled respiration was measured after addition of FCCP. Visceral fat contained more mitochondria per milligram of tissue than subcutaneous fat, but the cells were smaller. Robust, stable oxygen fluxes were found in both tissues, and coupled State 3 (GMOctS(D)) and non-coupled respiration were significantly (''P'' < 0.05) higher in visceral (0.95 +/- 0.05 and 1.15 +/- 0.06 pmol O(2) s^-1 mg^-1, respectively) compared with subcutaneous (0.76 +/- 0.04 and 0.98 +/- 0.05 pmol O(2) s^-1 mg^-1, respectively) adipose tissue. Expressed per mtDNA, visceral adipose tissue had significantly (''P'' < 0.05) lower mitochondrial respiration. Substrate control ratios were higher and uncoupling control ratio lower (''P'' < 0.05) in visceral compared with subcutaneous adipose tissue. We conclude that visceral fat is bioenergetically more active and more sensitive to mitochondrial substrate supply than subcutaneous fat. Oxidative phosphorylation has a higher relative activity in visceral compared with subcutaneous adipose tissue.Oxidative phosphorylation has a higher relative activity in visceral compared with subcutaneous adipose tissue.)
• Sahl 2021 Adipocyte  + (Adipose tissue mitochondrial function is g … Adipose tissue mitochondrial function is gaining increasing interest since it is good marker of overall health. Methodological challenges and variability in assessing mitochondrial respiration in fresh adipose tissue with high resolution respirometry are unknown and should be explored. Mitochondrial respiratory capacity (MRC) in human adipose tissue decline in a gradual manner when analyses are postponed 3h and 24h, with a statistically significant decline 24h after obtaining the biopsy. This decline in MRC is associated with a reduced integrity of the outer mitochondrial membrane at both time points. This study suggest that the optimal amount of tissue to be used is 20mg and that different technicians handling the biopsy do not affect MRC.ans handling the biopsy do not affect MRC.)
• Pino 2023 Abstract IOC162  + (Adipose tissue, which is the crucial energ … Adipose tissue, which is the crucial energy reservoir and endocrine organ for the maintenance of systemic glucose, lipid, and energy homeostasis, undergoes significant changes during aging. Ageing also impacts the circadian clock (CC) machinery of peripheral organs including white adipose tissue. Together, these alterations cause age-related disease in the elderly population. The aim of this study is to investigate the transcriptional expression of circadian clock genes, cell proliferation rates and mitochondrial capacity of adipose-derived stem cells (ASCs) isolated from abdominal subcutaneous white adipose tissue (scWAT) from old and young individuals.</br></br>10 old (5 females) and 10 young individuals (5 females) participated in this study. To measure CC related genes, proliferating ASCs were synchronized with 30% fetal bovine serum (FBS) for two hours, then media was replaced with 2% FBS and RNA was collected every six hours for a duration of 48 hrs and targeted gene expression was measured by qRT-PCR. To measure cells proliferation, ASCs were plated in 96 well plate and cell proliferation was measured with CellTiter-Glow luminescent cell viability kit (Promega, USA) for a period of 72 hrs. Mitochondrial capacity, oxygen consumption rates, were measured in proliferating ASCs via high-resolution respirometry using the Oxygraph-2K (Oroboros instruments, Innsbruck, Austria).</br></br>An increase in mRNA levels of CLOCK and PER2 and a loss of rhythmicity for CLOCK and CRY1 were observed in ASCs from older individuals compared to the young. mRNA levels and rhythmicity of BMAL, PER1, DBP, NR1D1 and NR1D2 were not altered by age. We are currently determining cell proliferation and mitochondrial capacity in ASCs. Overall, age does not seem to affect CC rhythmicity in ASCs isolated from scWAT from old and young individuals.from scWAT from old and young individuals.)
• Irion 2020 Stem Cells Int  + (Adipose-derived mesenchymal stromal cell ( … Adipose-derived mesenchymal stromal cell (AD-MSC) administration improves cardiac function after acute myocardial infarction (AMI). Although the mechanisms underlying this effect remain to be elucidated, the reversal of the mitochondrial dysfunction may be associated with AMI recovery. Here, we analyzed the alterations in the respiratory capacity of cardiomyocytes in the infarcted zone (IZ) and the border zone (BZ) and evaluated if mitochondrial function improved in cardiomyocytes after AD-MSC transplantation. Female rats were subjected to AMI by permanent left anterior descending coronary (LAD) ligation and were then treated with AD-MSCs or PBS in the border zone (BZ). Cardiac fibers were analyzed 24 hours (necrotic phase) and 8 days (fibrotic phase) after AMI for mitochondrial respiration, citrate synthase (CS) activity, F₀F₁-ATPase activity, and transmission electron microscopy (TEM). High-resolution respirometry of permeabilized cardiac fibers showed that AMI reduced numerous mitochondrial respiration parameters in cardiac tissue, including phosphorylating and nonphosphorylating conditions, respiration coupled to ATP synthesis, and maximal respiratory capacity. CS decreased in IZ and BZ at the necrotic phase, whereas it recovered in BZ and continued to drop in IZ over time when compared to Sham. Exogenous cytochrome c doubled respiration at the necrotic phase in IZ. F₀F₁-ATPase activity decreased in the BZ and, to more extent, in IZ in both phases. Transmission electron microscopy showed disorganized mitochondrial cristae structure, which was more accentuated in IZ but also important in BZ. All these alterations in mitochondrial respiration were still present in the group treated with AD-MSC. In conclusion, AMI led to mitochondrial dysfunction with oxidative phosphorylation disorders, and AD-MSC improved CS temporarily but was not able to avoid alterations in mitochondria function over time.d CS temporarily but was not able to avoid alterations in mitochondria function over time.)
• Santos-Silva 2023 Transl Psychiatry  + (Adolescent individuals exhibit great varia … Adolescent individuals exhibit great variability in cortical dynamics and behavioral outcomes. The developing adolescent brain is highly sensitive to social experiences and environmental insults, influencing how personality traits emerge. A distinct pattern of mitochondrial gene expression in the prefrontal cortex (PFC) during adolescence underscores the essential role of mitochondria in brain maturation and the development of mental illnesses. Mitochondrial features in certain brain regions account for behavioral differences in adulthood. However, it remains unclear whether distinct adolescent behavioral phenotypes and the behavioral consequences of early adolescent stress exposure in rats are accompanied by changes in PFC mitochondria-related genes and mitochondria respiratory chain capacity. We performed a behavioral characterization during late adolescence (postnatal day, PND 47-50), including naïve animals and a group exposed to stress from PND 31-40 (10 days of footshock and 3 restraint sessions) by z-normalized data from three behavioral domains: anxiety (light-dark box tests), sociability (social interaction test) and cognition (novel-object recognition test). Employing principal component analysis, we identified three clusters: naïve with higher-behavioral z-score (HBZ), naïve with lower-behavioral z-score (LBZ), and stressed animals. Genome-wide transcriptional profiling unveiled differences in the expression of mitochondria-related genes in both naïve LBZ and stressed animals compared to naïve HBZ. Genes encoding subunits of oxidative phosphorylation complexes were significantly down-regulated in both naïve LBZ and stressed animals and positively correlated with behavioral z-score of phenotypes. Our network topology analysis of mitochondria-associated genes found Ndufa10 and Cox6a1 genes as central identifiers for naïve LBZ and stressed animals, respectively. Through high-resolution respirometry analysis, we found that both naïve LBZ and stressed animals exhibited a reduced prefrontal phosphorylation capacity and redox dysregulation. Our findings identify an association between mitochondrial features and distinct adolescent behavioral phenotypes while also underscoring the detrimental functional consequences of adolescent stress on the PFC.sequences of adolescent stress on the PFC.)
• Mahdaviani 2014 Abstract MiP2014  + (Adrenergic stimulation of brown adipocytes … Adrenergic stimulation of brown adipocytes (BA) induces mitochondrial uncoupling, thereby increasing energy expenditure by shifting nutrient oxidation towards thermogenesis [1]. The brown adipocyte is a unique system to study the relationship between mitochondrial architecture and bioenergetic function. Here we describe that mitochondrial dynamics is a physiological regulator of adrenergically‐induced changes in energy expenditure. </br>Brown pre-adipocyes were harvested from 4-week-old wild-type male C57BL6/J mice and differentiated in culture. Oxygen consumption was measured using Seahorse XF24. Mitochondrial membrane potential was measured using TMRE and Zeiss LSM 710 confocal microscope. Measurements were taken before and after activation with NE (1 uM) and FFA (palmitate or oleate, 0.4 mM).</br></br>The sympathetic neurotransmitter norepinephrine (NE) induced complete and rapid mitochondrial fragmentation in BA, characterized by Drp1 phosphorylation and Opa1 cleavage. Mechanistically, NE‐mediated Drp1 phosphorylation was dependent on protein kinase‐A (PKA) activity [2], whereas Opa1 cleavage required mitochondrial depolarization, mediated by FFAs released as a result of lipolysis. This change in mitochondrial architecture was observed both in primary cultures and brown adipose tissue from cold‐exposed mice. Mitochondrial uncoupling, induced by NE in brown adipocytes, was reduced by inhibition of mitochondrial fission through transient Drp1 DN overexpression. Furthermore, forced mitochondrial fragmentation in BA through Mfn2 knock down increased the capacity of exogenous FFAs to increase energy expenditure.</br></br>These results suggest that, in addition to its ability to stimulate lipolysis, NE induces energy expenditure in BA by promoting mitochondrial fragmentation. Taken together these data reveal that adrenergically‐induced changes of mitochondrial dynamics are required for BA thermogenic activation and for the control of energy expenditure.and for the control of energy expenditure.)