Abstract 432: Elamipretide (BendaviaTM) Restores Aldehyde Dehydrogenase-2 Protein Levels and 4-Hydroxy-2-Nonenal Protein Adducts in Left Ventricular Myocardium of Dogs with Heart Failure

Abstract

Background: Reactive aldehydes such as 4-hydroxy-2-nonenal (4-HNE) are generated in the failing heart and contribute to cardiomyocyte injury and death and progressive left ventricular (LV) dysfunction. Aldehyde dehydrogenase-2 (ALDH2) plays a pivotal role in detoxifying mitochondrial (MITO) reactive aldehydes. We previously showed that long-term therapy with Elamipretide (ELA, Bendavia TM ), a novel MITO targeting peptide, improves LV systolic function and normalizes MITO function and rate of ATP synthesis in dogs with heart failure (HF). In this study, we examined the effects of long-term treatment with ELA on protein levels of 4-HNE adducts and ALDH2 in LV myocardium of dogs with coronary microembolization-induced HF (LV ejection fraction ~30%). Methods: LV tissue from 14 HF dogs randomized to 3 months monotherapy with subcutaneous injections of ELA (0.5 mg/kg once daily, n=7) or saline (control, CTR, n=7) and tissue from 6 normal (NL) dogs was used in the study. Using LV tissue extracts, 4-HNE protein adducts levels were quantified using a commercially available Elisa kit and expressed as ng/mg. In isolated MITO fractions prepared from LV tissue, protein levels of ALDH2 and porin, the latter used as an internal loading control, were determined by Western blotting coupled with Chemiluminescence. Band intensity was expressed in densitometric units (DU). Results: No changes in protein level of porin was observed among the 3 study groups (NL: 0.26±0.02; CTR: 0.24±0.01; BEN: 0.26±0.01 DU). 4-HNE protein adducts levels were increased in CTR dogs compared to NL dogs and treatment with ELA partially restored 4-HNE to near normal levels (NL: 185±21; CTR: 399±35*; ELA: 252 ± 18† ng/mg, *=p<0.05 vs. NL; †=p<0.05 vs. CTR). Compared to NL, dogs, ALDH2 protein levels were significantly reduced in HF CTR dogs (0.49±0.02 vs. 1.16±0.10; p<0.05). Treatment with ELA significantly increased ALDH2 protein compared to untreated CTR (0.74±0.02 DU, p<0.05). Conclusions: Long-term therapy with ELA normalizes ALDH2 and 4-HNE levels in LV myocardium of dogs with HF. Improved protein levels of ALDH2 in HF after therapy with ELA can account, in part, for the observed improvement of global LV function elicited by long-term therapy with ELA.