Figure 3.

Functional mast cells (MCs) induced cardiac fibroblast‐ (FB‐) to‐myofibroblast conversion through TGF‐β. (A) Wild‐type MCs induced the contraction of WT FBs in a collagen gel contraction assay to a similar extent as exogenous TGF‐β, and the effect was prevented by a TGF‐β neutralizing antibody. Gel contraction is expressed as the per cent shrinkage compared with a control gel without cells (n = 3, *P < 0.01 versus FBs alone). TGF‐β expression was increased in (B) infarcted but not in (C) non‐infarcted regions of the myocardium after MC and bone marrow (BM) cell transplantation 3 and 7 days after myocardial infarction and cell implantation by ELISA (n = 6, *P < 0.05 and **P < 0.01 versus medium‐injected).