Hahn 2014 Abstract MiP2014

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Validation of oxygen consumption measurements in muscle and fibroblasts from patients with mitochondrial diseases.
Link:
Hahn D
Mitochondr Physiol Network 19.13 - MiP2014

Hahn D, Nuoffer JM (2014)

Event: MiP2014

Diagnosis of mitochondrial disorders is mainly based on the analysis of OXPHOS complexes in muscle biopsies. However, normal enzyme activities do not rule out the presence of a mitochondrial disorder. Therefore, analysis of the integrated mitochondrial energy generating system by oxygen consumption is frequently used.

We compared the diagnostic value of respiratory versus enzymatic OXPHOS analysis in fibroblasts and muscle biopsies from patients with a genetically confirmed mitochondrial disease. A standardized substrate-uncoupler-inhibitor-titration (SUIT) protocol [1,2] was used for measuring respiration of permeabilized fibroblasts and single muscle fibers. OXPHOS enzyme activities were determined spectrophotometrically according to standard protocols. Only the combination of both measurements enables us to identify a mitochondrial disorder in all of the present patients (Table).

Moreover, specific flux control ratios showed higher diagnostic sensitivity than complex specific O2 fluxes. The established SUIT protocol is an important tool in the diagnostic process. Therefore, we recommend oxygen consumption measurements in addition to enzymatic OXPHOS analysis, to increase the number of identified patients.


O2k-Network Lab: CH Bern Nuoffer JM


Labels: MiParea: Respiration, mt-Medicine, Patients 

Stress:Mitochondrial disease  Organism: Human  Tissue;cell: Skeletal muscle, Fibroblast  Preparation: Permeabilized cells  Enzyme: Complex I, Complex II;succinate dehydrogenase, Complex IV;cytochrome c oxidase 

Coupling state: OXPHOS 

HRR: Oxygraph-2k  Event: C1, Poster  MiP2014: SUIT 

Affiliation

Dep Clin Chem, Inselspital, Bern, Switzerland. – dagmar.hahn@insel.ch

Table

Fibroblasts Positives Negatives Total Muscle Positives Negatives Total
Enzyme activity measurements 11 4 15 6 0 6
Oxygen consumption 14 1 15 5 1 6

References

  1. Hirsch A, Hahn D, Kempna P, Hofer G, Mullis P, Nuoffer JM, Flück CE (2012) Role of AMP-activated protein kinase on steroid hormone biosynthesis in adrenal NCI-H295R cells. PLoS ONE 7: e30956.
  2. Jackson CB, Nuoffer JM, Hahn D, Prokisch H, Haberberger B, Gautsch M, Häberli A, Gallati S, Schaller A (2014) Mutations in SDHD lead to autosomal recessive encephalomyopathy and isolated mitochondrial Complex II deficiency. J Med Genet 51: 170-5.