Myocardial blood capillary reaction in various forms of cardiac hypertrophy

Abstract

The ultrastructure of the myocardial blood capillary reaction in cardiac hypertrophy induced by physical exercise (swimming) and aortic stenosis was studied in the rat. Clear evidence of a neoformation of capillaries was obtained in the hearts of the swimming exercised rats, whereas no capillary reaction was observed in the hearts from rats with aortic stenosis. The growing capillaries first appeared as solid cords of pericyte-like cells in the interstitium. In the central core of these cords clefts appeared which were lined by endothelial-like cells containing pinocytotic vesicles. These cells might either be transformed pericytes or the result of endothelial proliferation along the interior of the cord. When the cleft established contact with the original capillary lumen it enlarged to form a continuation of this lumen.