Capillary changes in skeletal muscle of patients with essential hypertension

Arterial hypertension produces changes along the vascular tree. However, th ere are few reports on its effect on human muscle capillaries. This study d emonstrates the effects of essential hypertension on the capillaries of hum an quadriceps muscle. Muscle biopsy was taken from quadriceps femoris in eight men with recent di agnosis of essential hypertension, without treatment. Biopsies were also ta ken from eight normotensive men and were used as controls. Fiber types were classified by ATPase reaction, capillaries counted in a-amylase-PAS staine d sections and ultrastructure studied by conventional methods of transmissi on electron microscopy. No changes were found in capillaries or muscle fiber types by histochemical methods. However, electron microscopy revealed abnormal capillaries with e ndothelial cells infoldings into the lumen, as well as occluded or degenera ted capillaries. In some cases the endothelial cell area covered by pericyt es was increased. Basement membrane of capillaries was frequently increased in width, sometimes irregularly, and in other instances it was reduplicate d. In transversely sectioned capillaries lumen diameter was reduced and wal l thickness was increased, although total diameter was unchanged. In hypertensive patients the finding of some degenerated capillaries adjace nt to muscle fibers could be interpreted as the beginning of a process of r arefaction. Some capillaries showed morphological changes, and the ratio wa ll thickness/lumen was increased. Anat Rec 256:425-432, 1999. (C) 1999 Wile y-Liss, Inc.