MORPHOMETRY OF ARTERIOLES AND CAPILLARIES IN HEARTS OF SENESCENT MICE

Objective: The aim was to characterise quantitative changes in the cor onary arterioles and capillaries with aging in mice. Methods: Morphome tric analysis of the coronary resistance vessels was carried out in 12 ''young'' mice (63 days) and 11 ''old'' mice (650 days). Results: Com pared to hearts from young mice, those from senescent mice were heavie r, contained less water, and differed in several variables characteris ing terminal vessels. The main changes were a decreased capillary and arteriolar density, increased heterogeneity of capillary spacing, and larger arterioles with thicker walls. Conclusions: Aging of the murine myocardium is characterised by important changes at the level of the terminal vascular bed, the most prominent being a decrease in capillar y and arteriolar density. The decrease in arteriolar density is most p rominent in the classes of smallest vessels. All these changes represe nt an impairment of geometrical conditions for the oxygen supply to th e myocardial tissue.