Zhang Hong, Uthman Laween, Bakker Diane, Sari Sahinda, Chen Sha, Hollmann Markus W, Coronel Ruben, Weber Nina C, Houten Sander M, van Weeghel Michel, Zuurbier Coert J
Laboratory of Experimental Intensive Care and Anesthesiology, Department of Anesthesiology, Amsterdam Cardiovascular Sciences, Amsterdam Universitair Medische Centra, University of Amsterdam, Amsterdam, Netherlands.
Department of Anesthesiology, The Second Affiliated Hospital of Xi'an JiaoTong University, Xi'an, China.
Front Cardiovasc Med. 2020 Dec 4;7:592233. doi: 10.3389/fcvm.2020.592233. eCollection 2020.
Changes in cardiac metabolism and ion homeostasis precede and drive cardiac remodeling and heart failure development. We previously demonstrated that sodium/glucose cotransporter 2 inhibitors (SGLT2i's) have direct cardiac effects on ion homeostasis, possibly through inhibition of the cardiac sodium/hydrogen exchanger (NHE-1). Here, we hypothesize that Empagliflozin (EMPA) also possesses direct and acute cardiac effects on glucose and fatty acid metabolism of isolated type II diabetes mellitus () mouse hearts. In addition, we explore whether direct effects on glucose metabolism are nullified in the presence of an NHE-1 inhibitor. Langendorff-perfused type II diabetic db/db mouse hearts were examined in three different series: : C glucose perfusions ( = 32); : C palmitate perfusions ( = 13); and : C glucose + 10 μM Cariporide (specific NHE-1 inhibitor) perfusions ( = 17). Within each series, EMPA treated hearts (1 μM EMPA) were compared with vehicle-perfused hearts (0.02% DMSO). Afterwards, hearts were snap frozen and lysed for stable isotope analysis and metabolomics using LC-MS techniques. Hearts from series 1 were also analyzed for phosphorylation status of AKT, STAT3, AMPK, ERK, and eNOS ( = 8 per group). Cardiac mechanical performance, oxygen consumption and protein phosphorylation were not altered by 35 min EMPA treatment. EMPA was without an overall acute and direct effect on glucose or fatty acid metabolism. However, EMPA did specifically decrease cardiac lactate labeling in the C glucose perfusions (C labeling of lactate: 58 ± 2% vs. 50 ± 3%, for vehicle and EMPA, respectively; = 0.02), without changes in other glucose metabolic pathways. In contrast, EMPA increased cardiac labeling in α-ketoglutarate derived from C palmitate perfusions (C labeling of α-KG: 79 ± 1% vs. 86 ± 1% for vehicle and EMPA, respectively; = 0.01). Inhibition of the NHE by Cariporide abolished EMPA effects on lactate labeling from C glucose. The present study shows for the first time that the SGLT2 inhibitor Empagliflozin has acute specific metabolic effects in isolated diabetic hearts, i.e., decreased lactate generation from labeled glucose and increased α-ketoglutarate synthesis from labeled palmitate. The decreased lactate generation by EMPA seems to be mediated through NHE-1 inhibition.
心脏代谢和离子稳态的变化先于并驱动心脏重塑和心力衰竭的发展。我们之前证明，钠/葡萄糖协同转运蛋白2抑制剂（SGLT2i）对离子稳态有直接的心脏作用，可能是通过抑制心脏钠/氢交换体（NHE-1）实现的。在此，我们假设恩格列净（EMPA）对分离的II型糖尿病小鼠心脏的葡萄糖和脂肪酸代谢也具有直接和急性的心脏作用。此外，我们探讨在存在NHE-1抑制剂的情况下，对葡萄糖代谢的直接作用是否会消失。使用Langendorff灌流法对II型糖尿病db/db小鼠心脏进行了三个不同系列的实验：系列1：11 mM葡萄糖灌流（n = 32）；系列2：1 mM棕榈酸灌流（n = 13）；系列3：11 mM葡萄糖 + 10 μM卡立泊来德（特异性NHE-1抑制剂）灌流（n = 17）。在每个系列中，将用EMPA处理的心脏（1 μM EMPA）与用溶媒灌流的心脏（0.02% DMSO）进行比较。之后，将心脏速冻并裂解，用于使用液相色谱-质谱技术进行稳定同位素分析和代谢组学研究。对系列1的心脏还分析了AKT、STAT3、AMPK、ERK和eNOS的磷酸化状态（每组n = 8）。35分钟的EMPA处理未改变心脏机械性能、耗氧量和蛋白质磷酸化。EMPA对葡萄糖或脂肪酸代谢没有总体的急性直接作用。然而，在11 mM葡萄糖灌流中，EMPA确实特异性降低了心脏乳酸标记（乳酸的13C标记：溶媒组和EMPA组分别为58 ± 2%和50 ± 3%；P = 0.02），而其他葡萄糖代谢途径没有变化。相反，在1 mM棕榈酸灌流衍生的α-酮戊二酸中，EMPA增加了心脏标记（α-KG的13C标记：溶媒组和EMPA组分别为79 ± 1%和86 ± 1%；P = 0.01）。卡立泊来德对NHE的抑制消除了EMPA对11 mM葡萄糖中乳酸标记的作用。本研究首次表明，SGLT2抑制剂恩格列净在分离的糖尿病心脏中具有急性特异性代谢作用，即减少标记葡萄糖生成乳酸，并增加标记棕榈酸合成α-酮戊二酸。EMPA减少乳酸生成似乎是通过抑制NHE-1介导的。
