P.10.17 Morphological changes in skeletal muscle associated with chronic ischemia

Abstract

Chronic ischemia of the lower limbs is frequent in elderly individuals and is usually caused by arteriosclerosis and/or diabetes. In elderly people changes caused by chronic ischemia may influence the interpretation of a muscle biopsy analysis. It is therefore important to be aware of morphological alterations that may be caused by chronic ischemia. We investigated muscle biopsy specimens from the tibialis anterior muscle in 26 individuals (54–90 years of age, 13 with diabetes) amputated because of lower leg ischemia and compared them with 10 controls (72–78 years of age). None of the patients had a diagnosis of a primary neuromuscular disease. The specimens were investigated by routine histological techniques and by LX-PCR to identify mtDNA deletions. Morphological alterations in the 26 patients with chronic ischemia that were not present in controls included rimmed vacuoles (12 patients), interstitial fibrosis (14 patients), fiber type grouping (22 patients), group atrophy (19 patients) fibers with glycogen depletion (7 patients), necrotic fibers (6 patients), internalized nuclei (26 pateints), MHC class I upregulation (3 patients) and microangiopathy (13 patients). Cytochrome c oxidase deficient muscle fibres were identified in 25 patients (0.1–1.8% of the fibers) and in 7 controls (0.2–0.5% of the fibers). Multiple mtDNA deletions were identified in 16 patients and one control. None of the alterations were predominant in patients with diabetes. The results demonstrate that chronic ischemia is associated with marked morphological alterations in muscle that may mimic a primary myopathy. Neurogenic changes were frequent both among diabetic and non-diabetic patients.