The study shows that the peptide kisspeptin‑10 makes heart cells produce more collagen, which can lead to stiffening or scarring of the heart. It does this by turning on a protein called FAK and by blocking enzymes that normally break down collagen. This effect is not linked to the usual TGF‑β pathway.

The aim of the study was to evaluate the role of kisspeptin-10 (KiSS-10) in the regulation of collagen content in cardiac fibroblasts. An attempt was also made to describe the mechanism of the effect of KiSS-10 on collagen metabolism. The studies indicate that kisspeptin-10 significantly increases the content of intracellular collagen in the myocardium. KiSS-10 also elevates the level of phosphorylated focal adhesion kinase (FAK) in human cardiac fibroblasts. The inhibition of FAK negates the stimulatory effect of KiSS-10 on collagen deposition in vitro. These changes correlate with an increase in the level of propeptides of procollagen type I (PICP) and III (PIIICP) in fibroblast culture medium and mouse PIIICP in serum. Moreover, this hormone inhibits the release of metalloproteinases (MMP-1,-2,-9) and elevates the secretion of their tissue inhibitors (TIMP-1,-2,-4). KiSS-10 also enhances the expression of α1 chains of procollagen type I and III in vitro. Thus, KiSS-10 is involved in the regulation of collagen metabolism and cardiac fibrosis. Augmentation of collagen deposition by KiSS-10 is dependent on the protein synthesis elevation, inhibition of MMPs activity (increase of TIMPs release) or decrease of MMPs concentration. The profibrotic activity of KiSS-10 is mediated by FAK and is not dependent on TGF-β1.