KLK8 and diabetes mellitus: Using an STZ-induced diabetes model, a significant increase in the TGF-β1 mRNA and protein levels, as well as in the mRNA levels of TGF-β1 pro-EndMT transcriptional targets, was observed in heart tissues after 24 weeks of diabetes mellitus, which was significantly attenuated in KLK8-/- mice (Figure 2F, Figure 11E).