ACTA1 and Hepatic fibrosis: The most important known factor for accurate prognosis prediction in NASH is liver fibrosis.30 Western diet induced more liver fibrosis in WT mice than in caspase-2-deficient mice, as assessed by Sirius Red staining, hydroxyproline content, qRT-PCR for collagen-1α1, and immunohistochemistry for the myofibroblast markers, α-smooth muscle actin (α-SMA) and desmin (Figure 7a).