Aviscera Bioscience

Fat accumulation in obese individuals worsens the clinical outcomes of cardiovascular disease (CVD). Paradoxically, increased circulating adipocytokines secreted from visceral fat may confer cardioprotective effects. Visfatin, a novel adipocytokine, has anti-diabetic, anti-tumor, and pro-inflammatory properties. However, its effects on cardiomyocytes and the underlying mechanisms remain unknown. This article demonstrated that visfatin counteracted H2O2-induced apoptotic damage in H9c2 cardiomyocytes in a time-dependent manner. Qualitative immunofluorescence approaches demonstrated that visfatin pretreatment attenuated H2O2-induced DNA fragmentation (TdT-mediated dUTP-biotin nick end-labeling), phosphatidyl serine exposure (Annexin V/PI staining), and mitochondrial membrane potential (ΔΨm) depolarization (JC-1 staining). Biochemical studies on cardiomyoctes showed improved cell viability and reduced caspase-3 activation caused by visfatin pretreatment. Visfatin did not inhibit the death receptor-dependent apoptotic pathways, as characterized by its absence in both Fas and TNFR1 down-regulation. Instead, visfatin specifically suppressed the mitochondria-dependent apoptotic pathways, as characterized by changed levels of p53 and its downstream Bcl-2 family genes. Visfatin also up-regulated the protein levels of phosphorylated AMPK, and the anti-apoptotic action of visfatin was attenuated by the AMPK-specific inhibitor compound C. These results suggested that visfatin plays a critical role in cardioprotection by suppressing myocardial apoptosis via AMPK activation. These findings may be the missing link between obesity and CVD

Xiao J et al, J Cell Physiol. 2013 Mar;228(3):495-501. doi: 10.1002/jcp.24257.