Acute SGLT-2i treatment improves cardiac efficiency during myocardial ischemia independent of Na/H exchanger-1.

Aims: Sodium glucose co-transporter 2 inhibitors (SGLT2i) demonstrate cardioprotective benefits independent of a glucose lowering effect including preservation of cardiac function during a myocardial ischemia. Sodium‑hydrogen exchanger-1 (NHE-1), has been hypothesized to contribute to the cardiac effects of SGLT2i. We characterized the beneficial effects of acute pre-ischemia exposure to SGLT2i and explored the possibility that these effects are explained by NHE-1 inhibition.

Methods And Results: Swine were anesthetized and instrumented for invasive hemodynamic measurements. After baseline data collection, swine received a 15-30 min intravenous infusion of vehicle (DMSO), the SGLT2i canagliflozin (~1 mg/kg), or the NHE-1 inhibitor cariporide (~0.03 mg/kg) ending immediately prior to occlusion of the left circumflex artery. Measurements were obtained at baseline, during a 60-min complete occlusion of the circumflex coronary artery, and during a 2-h reperfusion period. Blood pressure, heart rate, left anterior descending artery flow, and associated myocardial oxygen consumption were unaffected by acute pre-treatment with canagliflozin or cariporide during ischemia and reperfusion. Acute pre-ischemic treatment with canagliflozin significantly increased diastolic filling and stroke work, producing a rightward shift in the Frank-Starling relationship, and also improved cardiac work efficiency relative to untreated control hearts during ischemia. Effects of NHE-1 inhibition with cariporide were modest and dissimilar. Examination of AP-1 cells transfected with wild-type NHE-1 and iPSC-derived cardiomyocytes confirmed dose-dependent-inhibition of NHE-1 activity by cariporide, while canagliflozin had no significant effect on NHE-1 activity.

Conclusion: Acute pre-treatment with SGLT2i produces cardioprotective effects during ischemia, including improved work efficiency. These effects are not explained by NHE-1 inhibition.

Translational Perspective: SGLT2 inhibitors have been shown to improve cardiac outcomes in patient including reducing myocardial infarction incidence and mortality. The mechanism(s) explaining this effect are not clear. This manuscript demonstrates a protective effect from acute SGLT2i exposure, as short as 15 min, prior to experimental infarction in swine. These effects were independent of NHE1 inhibition. These observations suggest that SGLT2 inhibitors can confer cardioprotective effects on a very short time scale. It is possible that such effects provide an ongoing contribution to ischemic protection even in the setting of chronic treatment.