IL13RA1 and hydrops fetalis: Indeed, loss of ECM leads to disruption of LV structure, cardiomyocyte slippage, adverse cardiac dilatation, and HF.26 On the other hand, uncontrolled accumulation of ECM, ie, fibrosis, facilitates myocardial stiffness and results in diastolic dysfunction and HF.27 Staining WT and Il13ra1−/− hearts revealed a significant decrease in perivascular collagen in the hearts of Il13ra1−/− mice (Figure 5B through 5D), which was consistent with reduced expression of myocardial collagens (collagens I, III) and thrombospondin‐1 (Figure 5E through 5G).