Abstract 15820: Differential Myocardial Gene Expression of Glucose Transporters in Heart Transplant Recipients With and Without Diabetes Mellitus

Abstract

Introduction: The Sodium Glucose cotransporter (SGLT) and glucose transporters(GLUTs) play a crucial role in cellular glucose transport. Although experimental data have shown differential regulation of GLUT4 and SGLT in diabetic cardiomyopathy, the impact of diabetes mellitus (DM) upon myocardial glucose transporters in humans remains undetermined. Aim: To better understand the impact of elevated glucose levels upon myocardial expression of glucose transporters, the endomyocardial gene expression of GLUT1, GLUT4 and SGLT1 was investigated in heart transplant(HTx) recipients, with and without DM, who received a heart from a DM- donor. Methods: At baseline(BL), immediately after HTx and 12 ± 2 months(FU) later, serial endomyocardial biopsies were procured in 26 Htx pts, free of clinical or histological rejection, at time of routine surveillance biopsy. Patients were categorized in DM+ (n = 13pts) and DM- (n = 13 pts), according to the presence of diabetes mellitus (DM) at FU. Results: Despite similar hemodynamics and HbA1c levels at BL, DM+ pts had higher HbA1c levels (46,00 ± 13,79 vs 38,33 ± 4,88; p < 0,05) at FU. No differences were noted in BL GLUT1, GLUT4 and SGLT gene expression between both groups. In DM- pts SGLT1(0,081 ± 0,080 vs 0,188 ± 0,108; p = 0,0036) , GLUT4(0,076 ± 0,068 vs 0,137 ± 0,065; p = 0,0011 )and GLUT1(0,020 ± 0,021 vs 0,022 ± 0,009; p = 0,043) increased significantly at FU whereas no change was observed in DM+ pts. Conclusion: Similar to experimental data, differential endomyocardial regulation in SGLT1 and GLUT4 was noted between DM+ and DM-pts with a blunted upregulation of glucose transporters at 1 year in DM+ HTx pts. These observations are in line with experimental data and suggest that myocardial glucose uptake is differentially regulated in DM+ HTx pts.