FSTL1 and diabetes mellitus: For instance, in ischemic cardiac injury models complicated by diabetes, exogenous supplementation or overexpression of FSTL1 has been shown to reduce fibrosis markers and improve cardiac function through the USP10/Notch1 axis, implying that in some metabolically abnormal settings, FSTL1 may tilt toward a more “anti-fibrotic/protective” output (Lu et al., 2021).