Hexarelin Attenuates Cardiomyocyte Hypertrophy Through Autophagy and mTOR Suppression

by Dr. James Ross

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Hexarelin and cardiomyocyte hypertrophy

Hexarelin is a synthetic growth hormone–releasing peptides with well-documented cardioprotective properties. Since autophagy is a critical process in maintaining cardiac homeostasis and preventing cellular damage, this study investigated the role of autophagy and its signaling regulation in the anti-hypertrophic effects of hexarelin on cardiomyocytes exposed to hypertrophic stress.

Angiotensin II (Ang-II) stimulation induced hypertrophy in H9C2 cardiomyocytes, accompanied by oxidative stress, apoptosis, and reduced cell viability. Treatment with hexarelin significantly mitigated these harmful effects, suppressing hypertrophy, lowering oxidative stress, reducing apoptosis, and improving overall cell survival. Importantly, hexarelin also enhanced autophagic activity in these hypertrophic cells.

Autophagy stimulation as a protective mechanism

To further probe the role of autophagy, rapamycin — a known autophagy stimulator — was applied to hypertrophic H9C2 cells. Rapamycin treatment decreased apoptosis, improved cell survival, and reduced hypertrophic cell size, consistent with autophagy’s role as a protective mechanism in cardiomyocytes.

Hexarelin likewise regulated autophagy by acting on upstream signaling pathways. Specifically, it inhibited the phosphorylation of the mammalian target of rapamycin (mTOR), a central negative regulator of autophagy. By suppressing mTOR activity, hexarelin promoted autophagic processes that protect against hypertrophy and apoptosis.

Mechanistic insights into hexarelin’s cardioprotective effects

The data indicate that hexarelin attenuates cardiomyocyte hypertrophy through an autophagy-dependent pathway. Its cardioprotective effects are closely associated with suppression of the mTOR signaling cascade, which in turn enhances autophagic activity and reduces apoptotic cell loss.

Thus, hexarelin appears to exert dual protective roles in stressed cardiomyocytes — reducing hypertrophic remodeling and preventing programmed cell death — largely by stimulating autophagy and regulating mTOR signaling.