Dual inhibition of SGLT 1 and 2 alleviates intracellular sodium overload in uraemic cardiomyopathy

Abstract

Abstract Background Chronic kidney disease (CKD) is a leading cause of mortality with the risk of developing cardiovascular disease higher than progression to kidney failure. The aetiology of uraemic cardiomyopathy is multifactorial and includes metabolic derangement. It was previously shown that elevated intracellular sodium (Nai) is causally linked to cardiac metabolic impairment and that targeting sodium homeostasis can reprogramme cardiac metabolism. Dual inhibition of sodium-glucose co-transporters (SGLT) 1 and 2 is an emerging therapy for CKD, however the impact on intracellular sodium and cardiac metabolism is yet to be elucidated. Purpose This study aimed to assess whether dual SGLT1/2 inhibitor sotagliflozin impacts cardiometabolic phenotype in CKD. Methods CKD was surgically induced by 5/6 nephrectomy in Wistar rats (n=46) for a period of 4 weeks, with chronic sotagliflozin treatment (5mg/kg) given for the last 3 weeks. Upon termination, hearts were Langendorff-perfused and studied using 31P and 23Na NMR spectroscopy (Sham n=7, CKD n=6, CKD+sotagliflozin n=5). To assess the cardiac-specific effect of the drug, acute sotagliflozin treatment (30mM) was delivered in the Langendorff perfusate to an additional group of CKD hearts (n=5). Furthermore, the effect of chronic sotagliflozin treatment on in vivo cardiac function (echocardiography n=23) and metabolic profile (1H NMR spectroscopy n=15) was assessed. Results CKD animals were characterized by significant renal dysfunction (2-fold increase in urea and creatinine vs sham, p<0.05), and HFpEF (EF(%) sham 82±2 vs CKD 80±1 p>0.05; diastolic dysfunction (E/A) sham 1.39±0.03 vs CKD 1.11±0.01, p=0.0018). Myocardial Nai was significantly elevated in CKD animals compared to sham controls (TQF 23Na 3.04±0.18 vs 2.01±0.32 arb units, p=0.03). Chronic sotagliflozin treatment didn’t impact renal or cardiac dysfunction. Neither chronic nor acute drug treatment impacted baseline CKD cardiac energetics (PCr/ATP sham 1.53±0.22, CKD 1.25±0.13, chronic 1.16±0.14, acute 1.18±0.13, p>0.05; ΔGATP (kJ/mol) sham -64±4, CKD -66±8, chronic -56±1, acute -59±3, p>0.05). However, both chronic and acute sotagliflozin treatment normalised the increased myocardial Nai (TQF 23Na chronic 2.17±0.12, acute 2.23±0.14 arb units, p>0.05 vs sham). Chronic drug dosing altered the systemic metabolic profile of CKD animals reducing the levels of circulating triglycerides and FFA (p<0.05) as well as altering metabolomic profile of liver, muscle and kidneys. Conclusion(s) We have shown that uraemic cardiomyopathy is characterised by HFpEF, elevated myocardial Nai and altered systemic metabolic profile. Both chronic and acute treatment with dual SGLT1/2 inhibitor sotagliflozin normalised myocardial Nai. The alleviation of Nai load could lead to improved cardiometabolic outcomes in CKD.