HUMAN HEART MAST-CELLS - ISOLATION, PURIFICATION, ULTRASTRUCTURE, ANDIMMUNOLOGICAL CHARACTERIZATION

We have isolated, partially purified, and characterized the mast cells from human heart tissue. The histamine content of left and right vent ricles and septum of hearts obtained from 25 patients undergoing heart transplantation was 5.4 +/- 0.6, 5.3 +/- 0.5, and 5.6 +/- 0.5 mu g/g of wet tissue, respectively. Ultrastructural study of cardiac mast cel ls revealed scroll, crystal, and mixed granules, homogeneously dense g ranules, and lipid bodies in the cytoplasm. A mild collagenase digesti on was used to disperse the heart mast cells; the average yield was 3. 2 +/- 0.6% (range: 0.8 to 13.6%). The average histamine and tryptase c ontent/heart mast cells was 3.3 +/- 0.2 pg (n = 25) and 24.2 +/- 4.3 m u g/10(6) cells (n = 11), respectively. Survival of cardiac mast cells after overnight culture was 71.9 +/- 5.4% (n = 23). The purification of human heart mast cells can be brought from less than 0.1 to 12% by a combination of low-speed centrifugation over albumin (2%) solution a nd Percoll gradient. Viability as shown by trypan blue exclusion was g reater than 90%. Heart mast cells released histamine in response to im munologic (anti-IgE, anti-Fc epsilon RI, and C5a) and nonimmunologic s timuli (recombinant human stem cell factor, A23187, and compound 48/80 ) but did not respond to substance P, FMLP, 12-O-tetradecanoylphorbol- 13-acetate, or acetylcholine. There was a linear correlation between t he percentage of release caused by anti-IgE and anti-Fc epsilon RI, wh ereas there was no correlation between the release caused by C5a and a nti-IgE-mediated stimuli. Cross-linking with anti-IgE of IgE on heart mast cells induced the release of tryptase (10.1 +/- 2.1 mu g/10(7) ce lls; n = 10) and the de novo synthesis of PGD(2) (17.3 +/- 4.3 ng/10(6 ) cells; n = 10) and of leukotriene C-4 (19.1 +/- 4.5 ng/10(6) cells; n = 10). There was a linear correlation between the percentage of hist amine secretion and tryptase release (r = 0.67; p < 0.001) induced by cross-linking of Fc epsilon RI. Similarly, there was a significant cor relation between percentage of histamine secretion and PGD(2) (r = 0.6 3; p < 0.001) and LTC(4) (r = 0.64; p < 0.001) release. Immunoelectron microscopy demonstrated the presence of chymase in cardiac mast cells . Mast cells isolated from human heart can be a useful model with whic h to study the role of these cells and their mediators in cardiac anap hylaxis and cardiovascular diseases.