Long-Term Treatment with Empagliflozin Attenuates Renal Damage in Obese Zucker Rat

Empagliflozin improves aortic injury in obese mice by regulating fatty acid metabolism

Background

Empagliflozin has been shown in clinical studies to lower the risk of adverse cardiovascular events. Using proteomics, the current study aims to determine whether empagliflozin reduces aortic alterations in obese mice and to investigate its molecular mechanism of action.

Methods

We constructed obese mice and then treated them with empagliflozin. Changes in the weight of the mice were recorded. Blood glucose and lipid levels were measured in each group of mice, and changes in pulse wave velocity and aortic structure were recorded. In addition, changes in aortic protein expression were detected by proteomics and analyzed bioinformatically.

Results

Proteomics results showed that 507 differentially expressed proteins (DEPs) were identified in the comparison of normal and obese mice, while 90 DEPs were identified in the comparison of obese and empagliflozin-treated mice. Examination of these three groups revealed that DEPs were largely associated with the digestion of unsaturated fats. Among them, empagliflozin significantly reduced the expression of fatty acid synthase (FASN), acyl-CoA desaturase 3 (SCD3), ACSL1. and ACSL5 in the aorta of obesity-induced mice, and there was a close relationship between the four.

Conclusion

Empagliflozin reduced the protein expression of FASN, SCD3, ACSL1, and ACSL5 in the aorta of obese mice and improved aortic fatty acid metabolism and reduced vascular stiffness for vasoprotective effects.

Empagliflozin alone and in combination with metformin mitigates diabetes-associated renal complications

Diabetes mellitus is a major public health concern, often leading to undiagnosed micro- and macrovascular complications, even in patients with controlled blood glucose levels. Recent evidence suggests that empagliflozin and metformin have renoprotective effects in addition to their hypoglycemic action. This study investigated the potential protective effect of empagliflozin and metformin on diabetic renal complications. Forty-two adult male Sprague Dawley rats were randomized into six groups: normal control, diabetic control, metformin (250 mg/kg), empagliflozin (10 mg/kg), and combination therapy groups. Type 2 diabetes was induced in rats by a single intraperitoneal injection of streptozotocin (40 mg/kg) following two weeks of 10% fructose solution in their drinking water. Blood glucose, creatinine, urea nitrogen, inflammatory markers (IL-6, TNF-α), and renal tissue caspase-3 were assessed after eight weeks. Blood glucose, urea, creatinine, serum IL-6, TNF-α, and tissue caspase-3 were significantly decreased in the treatment groups compared to the diabetic group. The histopathological findings revealed that treatment with empagliflozin and/or metformin improved the damage in the renal tissue caused by diabetes-induced nephropathy. Moreover, co-administration of empagliflozin and metformin resulted in even better outcomes. Our data revealed that empagliflozin and metformin could improve renal function and decrease inflammation and apoptosis in diabetic animals, delaying the progression of diabetic nephropathy. Combined treatment with metformin and empagliflozin proved to have an additive protective action on renal tissue.

A systematic review on renal effects of SGLT2 inhibitors in rodent models of diabetic nephropathy

We have performed a systematic review of studies reporting on the renal effects of SGLT2 inhibitors in rodent models of diabetes. In 105 studies, SGLT2 inhibitors improved not only the glycemic control but also various aspects of renal function in most cases. These nephroprotective effects were similarly reported whether treatment with the SGLT2 inhibitor started concomitant with the onset of diabetes (within 1 week), early after onset (1-4 weeks) or after nephropathy had developed (>4 weeks after onset) with the latter probably having the greatest translational value. They were observed across various animal models of type 1 and type 2 diabetes/obesity (4 and 23 models, respectively), although studies in the type 2 diabetes model of db/db mice more often had negative data than in other models. Among possibly underlying pathophysiological mechanisms of nephroprotection, treatment with SGLT2 inhibitors had beneficial effects on lipid metabolism, blood pressure, glomerulosclerosis as well as renal tubular fibrosis, apoptosis, oxidative stress, and inflammation. These pathomechanisms highly influence atherosclerosis and renal health, which are two major factors that lead to an enhanced mortality in patients with diabetes and/or chronic kidney disease. Interestingly, renal SGLT2 inhibitor effects did not always correlate with those on glucose homeostasis, particularly in a limited number of direct comparative studies with other anti-diabetic treatments, indicating that nephroprotection may at least partly occur by mechanisms other than improving glycemic control. Our analyses did not provide evidence for different nephroprotective efficacy between SGLT2 inhibitors. Importantly, only four of 105 studies reported on female animals, and none provided direct comparative data between sexes. We conclude that more data on female animals and more direct comparative studies with other anti-diabetic compounds and combinations of treatments are needed.

Gut micobiota alteration by Lactobacillus rhamnosus reduces pro-inflammatory cytokines and glucose level in the adult model of Zebrafish

Objective

Type 2 diabetes mellitus (T2DM) is still a challenge for physicians to manage patient’s circumstances. It is assumed that alterations in the normal flora may be involved in the pathogenesis of T2DM through inducing chronic inflammation. To investigate the effect of Lactobacillus rhamnosus as a common probiotic on T2DM, we induced an experimental model of T2DM in adult male Zebrafish by gradient hyper-glucose accumulation methodology.

Results

In this trial 3-month old male adult Zebrafish were divided in to four groups including two control groups and T2DM induced groups with or without probiotic treatment. After 5 days of acclimation, T2DM was induced by a gradient hyper-glucose accumulation methodology. Diabetic fishes had statistically abnormal blood glucose and pro-inflammatory cytokine levels compared to control group (p = 0.0001). These results suggest that probiotic intervention decreased the blood glucose level in the T2DM-P group by decreasing pro-inflammatory cytokines responsible for signaling in T2DM therapeutic modalities.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05706-5.

Sodium-glucose cotransporter 2 inhibition prevents renal fibrosis in cyclosporine nephropathy

AIMS

Sodium-glucose cotransporter 2 (SGLT2) inhibitors, a new class of antidiabetic drugs, are nephroprotective in case of diabetes, but whether a similar beneficial effect may be detectable also in case of chronic non-diabetic kidney diseases remains still unknown. The aim of this study was to evaluate the effects of empagliflozin, a SGLT-2 inhibitor, on the progression of cyclosporine nephropathy, in the absence of diabetes.

METHODS

Sprague Dawley rats (n = 27) have been fed with low-salt diet starting 10 days before the beginning and finished at the end of the experimental period. Cyclosporine-A (CsA, 15 mg/kg/day, intraperitoneal injection, n = 8) and CsA plus empagliflozin (Empa, 10 mg/kg/day, per os, n = 7) were administered for 4 weeks. The control groups were treated with placebo (Control, n = 7) or empagliflozin (Control + Empa, n = 5). Blood pressure (plethysmographic method) was measured at the beginning and at the end of the experimental period. At the end of the experimental protocol, the kidneys were excised for histomorphometric analysis of renal fibrosis and for immunohistochemical evaluation of inflammatory infiltrates (monocytes/macrophages), type I and type IV collagen expression, and tyrosine hydroxylase expression, used as marker of sympathetic nerve activity.

RESULTS

CsA-treated rats showed a significant increase (p < 0.01) in blood pressure, which was reduced by administration of empagliflozin (p < 0.05). CsA administration caused an increase in glomerular and tubulo-interstitial fibrosis (p < 0.05), renal inflammatory infiltrates (p < 0.05), type I and type IV collagen expression (p < 0.01), and tyrosine hydroxylase expression (p < 0.01) as compared to the control rats and control + Empa-treated rats. Treatment with empagliflozin in CsA-treated rats reduced glomerular (p < 0.01) and tubulo-interstitial fibrosis (p < 0.05), type I and type IV collagen expression (p < 0.01), inflammatory cell infiltration (p < 0.01) and tyrosine hydroxylase expression (p < 0.05), as compared to rats treated with CsA.

CONCLUSION

Empagliflozin administration caused a reduction in blood pressure in CsA-treated rats and showed a protective effect on CsA nephropathy by decreasing renal fibrosis, type I and type IV collagen expression, macrophage infiltration and tyrosine hydroxylase expression. These data suggest that empagliflozin promotes nephroprotection also in non-diabetic kidney disease.

Empagliflozin Contributes to Polyuria via Regulation of Sodium Transporters and Water Channels in Diabetic Rat Kidneys

Besides lowering glucose, empagliflozin, a selective sodium-glucose cotransporter-2 (SGLT2) inhibitor, have been known to provide cardiovascular and renal protection due to effects on diuresis and natriuresis. However, the natriuretic effect of SGLT2 inhibitors has been reported to be transient, and long-term data related to diuretic change are sparse. This study was performed to assess the renal effects of a 12-week treatment with empagliflozin (3 mg/kg) in diabetic OLETF rats by comparing it with other antihyperglycemic agents including lixisenatide (10 μg/kg), a glucagon-like peptide receptor-1 agonist, and voglibose (0.6 mg/kg), an α-glucosidase inhibitor. At 12 weeks of treatment, empagliflozin-treated diabetic rats produced still high urine volume and glycosuria, and showed significantly higher electrolyte-free water clearance than lixisenatide or voglibose-treated diabetic rats without significant change of serum sodium level and fractional excretion of sodium. In empagliflozin-treated rats, renal expression of Na⁺-Cl^- cotransporter was unaltered, and expressions of Na⁺/H⁺ exchanger isoform 3, Na⁺-K⁺-2Cl^- cotransporter, and epithelial Na⁺ channel were decreased compared with control diabetic rats. Empagliflozin increased an expression of aquaporin (AQP)7 but did not affect AQP3 and AQP1 protein expressions in diabetic kidneys. Despite the increased expression in vasopressin V2 receptor, protein and mRNA levels of AQP2 in empagliflozin-treated diabetic kidneys were significantly decreased compared to control diabetic kidneys. In addition, empagliflozin resulted in the increased phosphorylation of AQP2 at S261 through the increased cyclin-dependent kinases 1 and 5 and protein phosphatase 2B. These results suggest that empagliflozin may contribute in part to polyuria via its regulation of sodium channels and AQP2 in diabetic kidneys.