Matallo 2013 Abstract MiP2013
|Matallo J, Gröger M, Wagner K, Wagner F, Radermacher P, Calzia E (2013) Effects of mechanical ventilation after blunt chest trauma on diaphragmatic mitochondrial respiration in chronically cigarette smoke exposed mice: A clinically relevant model? Mitochondr Physiol Network 18.08.|
Previous studies clearly indicate that diaphragm disuse during mechanical ventilation (MV) rapidly leads to atrophy of this muscle . On the biochemical level, this MV related diaphragmatic weakness is due to an increased production of reactive oxygen species (ROS) and impaired mitochondrial respiration [2,3]. The dysfunction of the diaphragm is a major cause of difficult weaning from MV. This issue is a leading problem in critical care medicine, and a particularly severe challenge in patients with pre-existing pulmonary disorders like chronic obstructive pulmonary disease (COPD). However, no data are available yet on the effects of MV on diaphragmatic function especially in subjects with pulmonary conditions resembling human COPD. Therefore, our aim was to measure mitochondrial respiratory activity in diaphragm and heart in chronically cigarette smoke exposed (CSE) mice, i.e. in a COPD-model, after a standardized blunt chest trauma  and 5 hours of mechanical ventilation.
Maximum mitochondrial respiration in small, homogenized biopsies of heart and diaphragm was measured in the FCCP-induced uncoupled state under combined stimulation of the respiratory system with Complex I (pyruvate, malate and glutamate) and Complex II (succinate) substrates using an Oxygraph-2k (Oroboros Instruments, Austria). We studied 4 groups of animals (controls vs. CSE with or without trauma and MV, N = 5-8).
Only in the diaphragm of CSE mice mitochondrial respiration already decreased after the short period of MV (Figure 1).
In contrast to healthy individuals, in subjects suffering from chronic pulmonary diseases and airway obstruction similar to human COPD diaphragmatic mitochondrial dysfunction already results from short periods of MV and inactivity of the respiratory muscles.
• O2k-Network Lab: DE Ulm Radermacher P
Labels: MiParea: Respiration, mt-Medicine Pathology: COPD
Organism: Mouse Tissue;cell: Heart, Skeletal muscle, Lung;gill Preparation: Homogenate
Coupling state: ET Pathway: NS HRR: Oxygraph-2k
Figure 1: Maximum mitochondrial respiration in homogenised diaphragm (left) and heart biopsies (right; means±SD). Control (left bars) vs. MV (right bars) in wildtype (WT) and cigarette smoke exposed (CSE) mice.
Dept of Anesthesia, Section of Anesthesiological Pathophysiology and Process Development, Ulm University, Germany
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