Immunologic and non-immunologic release of histamine and tryptase from human heart mast cells

Mast cells are present in the human heart [1], and coronary arteries of patients with ischemic heart disease contain more histamine and mast cells than do those of non cardiac patients [2]. Moreover, the in vitro immunologic activation of fragments of human right atrial appendages induces the release of histamine [1]. Human mast cells from lung, skin, gut, uterus, and synovia are immunologically and functionally heterogenous [3]. For instance, skin mast cells can be activated by a variety of secretagogues, e.g. substance P0 48/80, C5a, and morphine that do not activate other mast cell types [3]. The complex heterogeneity of human mast cells isolated from different organs suggests that certain functions of these cells are regulated by the local microenvironment. Therefore, it is important to develop techniques to retrieve mast cells from different anatomic sites. In this study we have identified some immunologic and non-immunologic stimuli that activate human heart mast cells (HHMC) and measured a number of preformed mediators released upon activation of these cells.