Mast cells in the circulatory system of man.

This report is based upon a study of multiple segments of the cardiovascular system of 200 deceased persons and selected surgical specimens. M\last (ells are present in the adventitia of all blood vessels. Only the largest vessels have mast cells in the intima and subintima as well. In this location the number of mast cells is highest in grossly normal but microscopicallv e(lematous areas. Mast cells are rarely present in early and are never present in adlvanced atheromiaitous lesions. The theory is advanced that mast (ells are attracted by plasma insudate to release heparin for degradation of lipoproteins. Thus, mast cells might play a role in atherogenesis. MUI7CH has been written about mast cells,'' 2 but our knowledge is still fragmentary and controversial. References to the presence of mast cells in blood vessels of animals are avail-able3-" but there is none regarding their occur-renee in vessels of man. A single paper deals with mast cells in the human heart.'2 Lack of information about mast cells in human blood vessels prompted this study.