TRPV4 and cutaneous mastocytosis: Furthermore, TRPV4−/− of the HF(iso) group developed less CM hypertrophy (27% reduction) and remarkably reduced cardiac fibrosis (58% reduction in collagen content) compared to their counterpart TRPV4+/+ treated with chronic isoproterenol, differences that were statistically significant (Figure 3D,E, dark red versus dark blue bars).