Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, CA, USA.
Department of Pharmacology, University of California San Diego, La Jolla, CA, USA.
Nephrol Dial Transplant. 2024 Sep 27;39(10):1565-1573. doi: 10.1093/ndt/gfae060.
What mechanisms can link the inhibition of sodium-glucose cotransporter 2 (SGLT2) in the early proximal tubule to kidney and heart protection in patients with and without type 2 diabetes? Due to physical and functional coupling of SGLT2 to other sodium and metabolite transporters in the early proximal tubule (including NHE3, URAT1), inhibitors of SGLT2 (SGLT2i) reduce reabsorption not only of glucose, inducing osmotic diuresis, but of other metabolites plus of a larger amount of sodium than expected based on SGLT2 inhibition alone, thereby reducing volume retention, hypertension and hyperuricemia. Metabolic adaptations to SGLT2i include a fasting-like response, with enhanced lipolysis and formation of ketone bodies that serve as additional fuel for kidneys and heart. Making use of the physiology of tubulo-glomerular communication, SGLT2i functionally lower glomerular capillary pressure and filtration rate, thereby reducing physical stress on the glomerular filtration barrier, tubular exposure to albumin and nephrotoxic compounds, and the oxygen demand for reabsorbing the filtered load. Together with reduced gluco-toxicity in the early proximal tubule and better distribution of transport work along the nephron, SGLT2i can preserve tubular integrity and transport function and, thereby, glomerular filtration rate in the long-term. By shifting transport downstream, SGLT2i may simulate systemic hypoxia at the oxygen sensors in the deep cortex/outer medulla, which stimulates erythropoiesis and, together with osmotic diuresis, enhances hematocrit and thereby improves oxygen delivery to all organs. The described SGLT2-dependent effects may be complemented by off-target effects of SGLT2i on the heart itself and on the microbiome formation of cardiovascular-effective uremic toxins.
有哪些机制可以将早期近曲小管中钠-葡萄糖共转运蛋白 2(SGLT2)的抑制作用与 2 型糖尿病患者和非糖尿病患者的肾脏和心脏保护联系起来?由于 SGLT2 与早期近曲小管中的其他钠和代谢物转运体(包括 NHE3、URAT1)的物理和功能偶联,SGLT2 抑制剂(SGLT2i)不仅减少了葡萄糖的重吸收,导致渗透性利尿,而且减少了其他代谢物以及比单独抑制 SGLT2 预期更多的钠的重吸收,从而减少了容量潴留、高血压和高尿酸血症。SGLT2i 的代谢适应包括类似于禁食的反应,增强脂肪分解和酮体的形成,酮体作为肾脏和心脏的额外燃料。利用管-球通讯的生理学,SGLT2i 可降低肾小球毛细血管压力和滤过率,从而降低肾小球滤过屏障、肾小管暴露于白蛋白和肾毒性化合物以及重吸收滤过负荷所需的氧气需求的物理应激。与早期近曲小管中减少的糖毒性以及沿肾单位更好地分配转运工作相结合,SGLT2i 可以长期保持肾小管完整性和转运功能,从而保持肾小球滤过率。通过将转运向下游转移,SGLT2i 可能会在深层皮质/外髓质中的氧气传感器模拟全身缺氧,刺激红细胞生成,并与渗透性利尿一起,提高红细胞比容,从而改善向所有器官的氧气输送。SGLT2i 对心脏本身和对心血管有效尿毒症毒素的微生物组形成的非靶向作用可能补充 SGLT2 依赖性作用。