What Is Humanin?

“Humanin (HN) is an endogenous mitochondria-derived peptide that has cytoprotective effects and reduces oxidative stress. The present study aimed to test the hypothesis that chronic supplementation of exogenous HN in middle-aged mice could prevent and reverse cardiac fibrosis and apoptosis in the aging heart.”

HNG treatment significantly increased the ratio of cardiomyocytes to fibroblasts in aging hearts, as shown by the percentage of each cell type in randomly chosen fields after immunofluorescence staining. The percentage of other cell types did not change among these groups… Furthermore, the increased collagen deposition in aged hearts was significantly reduced after HNG treatment, as indicated by picrosirius red staining. HNG treatment also reduced in aging mice cardiac fibroblast proliferation and attenuated transforming growth factor-β1, fibroblast growth factor-2, and matrix metalloproteinase-2 expression. Myocardial apoptosis was inhibited in HNG-treated aged mice.”

“Cardiac fibrosis is a biological process that increases with age and contributes to myocardial dysfunction. Humanin is an endogenous mitochondria-derived peptide that has cytoprotective effects and reduces oxidative stress. Here, we demonstrate, for the first time, that exogenous humanin treatment attenuated myocardial fibrosis and apoptosis in aging mice. We also detected upregulated Akt/glycogen synthase kinase-3β pathway in humanin analog-treated mice, which might be the mechanism involved in the cardioprotective effect of humanin analog in aging mice.”

HNG inhibited interstitial fibrosis and reduced fibroblast proliferation in the aging myocardium.

Picrosirius red staining revealed that interstitial collagen deposition increased significantly in aged mice compared with young mice (0.24 ± 0.06% vs. 0.02 ± 0.01%, P < 0.01; Fig. 2, A, B, and D). Upon HNG (Humanin) treatment, a reduction in cardiac interstitial collagen deposition was observed in aged mice (to 0.07 ± 0.03%, P < 0.05; Fig. 2, B–D). In perivascular fibrosis, there was no significant difference among groups.

Sourcing Study: https://journals.physiology.org/doi/full/10.1152/ajpheart.00685.2017