Background: Mitochondrial quality control (MQC) is crucial for maintaining mitochondrial fitness. We investigated MQC signaling in muscle of old hip-fractured patients.
Methods: Twenty-three patients, enrolled in the Sarcopenia in HIp FracTure (SHIFT) study, were categorized into old (OL; n=8) and very old groups (VOL; n=15) using 85years as the cut-off. The expression of a set of MQC signaling proteins was assayed in vastus lateralis muscle biopsies.
Results: The content of lysosome-associated membrane protein 2, microtubule-associated protein 1 light chain 3B, optic atrophy protein 1, fission protein 1 (Fis1), peroxisome proliferator-activated receptor-γ coactivator-1α, and forkhead box O3 was unvaried between groups. Conversely, the protein expression of mitofusin 2 (Mfn2) as well as the fusion index (Mfn2/Fis1) was increased in VOL patients.
Conclusions: Muscle mitochondrial dynamics appear to be shifted toward fusion in very advanced age. Whether this phenomenon represents an adaptation to cope with age-dependent mitochondrial dysfunction warrants further investigation.
Keywords: Autophagy; Fission; Mitochondrial biogenesis; Mitochondrial quality control (MQC); Muscle aging; Sarcopenia.
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