Abstract 14127: The Role of Sodium Glucose Co-Transporter 1 in Hyperglycemia Ischemia Reperfusion Injury

Abstract

Introduction: Hyperglycemia is a common finding in ACS patients in both diabetic and non-diabetic, it is considered a powerful predictor of prognosis and mortality. The role of hyperglycemia in ischemia-reperfusion injury is not fully understood, whether the Sodium Glucose Co-Transporter 1(SGLT1) plays a role in increase injury, before and/or after reperfusion, remains to be elucidated. SGLT2 inhibitors clinical trials have shown significant improvements in cardiovascular outcomes in diabetic and non-diabetic, yet the mechanism is not fully understood and whether SGLT1 plays a role in infarct augmentation remains to be elucidated. Hypothesis: High glucose at reperfusion leads to excess myocardial injury and the increased injury is mediated through the activity of SGLT1. Methods: RT-PCR and in-situ hybridization (RNAScope) combined with Immunofluorescence integrated co detection with different cell marker techniques were used to detect SGLT1 mRNA expression in Sprague-Dawley whole myocardium and Zucker diabetic rats. An Ex-vivo Langendorff ischemia-reperfusion perfusion model was used to study the effect of high glucose on myocardium at reperfusion. Canagliflozin a non-selective SGLT inhibitor (1μmoL/L to block the SGLT1 and SGLT2 transporter and 5nmol/L to block only the SGLT2 transposer) and Mizagliflozin a selective SGLT1 inhibitor (100nmol/L) was introduced following ischemia at two different glucose concentration concentrations at reperfusion and its effect on infarct size measured using triphenyltetrazolium chloride (TTC) staining. Results: Our data reveal that SGLT1 is homogenously expressed throughout the myocardium and is particularly evident within the vasculature. We have also demonstrated that high-glucose mediated injury in the isolated, perfused heart model and it is abrogated through the administration of both mixed SGLT2/SGLT1 inhibitor, canagliflozin, at a dose that inhibits both SGLT2 and SGLT1, and through the administration of novel specific SGLT1 inhibitor, Mizagliflozin. Conclusions: We have shown that SGLT1 is present in the myocardium. Hyperglycemia appears to augment myocardial infarction and inhibition of SGLT1 attenuates this increase.