MYOPATHY IN BONE LOSS OF AGING - IMPROVEMENT BY TREATMENT WITH 1ALPHA-HYDROXYCHOLECALCIFEROL AND CALCIUM

Eleven patients with the bone loss of ageing were treated with the vitamin D analogue 1α-hydroxycholecalciferol and calcium for 3-6 months. Muscle biopsies were taken from the vastus lateralis before and after the treament and the activity of several enzymes was measured. Succinate dehydrogenase and total phosphorylase activities, which are a measure of the oxidative capacity, were low and increased significantly with the treatment. The lactate dehydrogenase activity, which can be taken as a measure of the anaerobic metabolism, was normal and did not change with treatment. The phosphagen stores, ATP and creatine phosphate were low and increased to normal with treatment. Histochemical classification of the fibre composition revealed that the treatment induced an increase in the relative number of fast-twitch a (FT(a) or type II A) fibres accompanied by a reduction of the fast-twitch b (FT(b) or type II B) fibres. The cross-sectional area of the FT(a) fibres also increased with the treatment. The present findings indicate that treatment with the active vitamin D analogue 1α-hydroxycholecalciferol, and calcium improves the myopathy associated with the bone loss of ageing.