Human cardiac fibroblasts and receptors for angiotensin II and bradykinin:A potential role for bradykinin in the modulation of cardiac extracellularmatrix

Evidence derived from in vivo experimental studies performed with angiotens in converting enzyme inhibitors (ACEi) indicates that these agents are capa ble of modulating the process of cardiac hypertrophy and fibrosis. The anti fibrotic actions of ACEi are thought to be derived from their capacity to b lock the production of angiotensin II and, thus, its action on the cardiac fibroblast. However, in contrast to rat hearts, human myocardium has low le vels of angiotensin II receptors. Evidence indicates that enhanced bradykin in (BK) levels result from the action of ACEi. In vivo data derived from th e use of the BK blocker HOE140 suggests a role for BK in repressing the pro cess of cardiac hypertrophy and fibrosis. Little is known as to the abundan ce of angiotensin II and BK receptors in human cardiac fibroblasts. Data pr esented in this study indicates that in cultured human cardiac fibroblasts there is apparently few angiotensin II receptors whereas as in other specie s there is evidence for the presence of BK receptors. Further studies need to be performed to establish the potential role that BK plays in modulating human cardiac fibroblast function.