A novel technique for isolating functional mast cells from the heart.

OBJECTIVE AND
DESIGN: The purpose of this study was to determine the feasibility of adapting peritoneal and pleural mast cell isolation techniques to recover cardiac mast cells that retain their functional response to the secretagogue, compound 48/80.
METHODS: Using a novel protocol in rats, viable epicardial mast cells were recovered by aspiration of HBSS injected into the pericardial space. Functionality of these cells was determined by ELISA quantification of histamine release in response to compound 48/80, calcium ionophore A23187 and substance P. Mast cell phenotype was determined based on the presence of chymase and tryptase demonstrated by immunofluorescence, alcian blue-safranin staining, and Western blotting.
RESULTS: Mast cells isolated in this manner have low basal rates of histamine release and are highly responsive to these secretagogues. These epicardial mast cells were of the connective tissue type, which is consistent with previous reports characterizing cardiac mast cells isolated from the heart by enzymatic dispersion techniques.
CONCLUSIONS: This novel pericardial aspiration technique facilitates the straightforward characterization of isolated epicardial mast cell functionality in a controlled in vitro environment, furthering our understanding of their contribution to myocardial disease.