Antihypertensive and metabolic effects of empagliflozin in Ren-2 transgenic rats, an experimental non-diabetic model of hypertension

Hepatoprotective and cardioprotective effects of empagliflozin in spontaneously hypertensive rats fed a high-fat diet

A combination of liver and heart dysfunction worsens the prognosis of human survival. The aim of this study was to investigate whether empagliflozin (a sodium-glucose transporter-2 inhibitor) has beneficial effects not only on cardiac and renal function but also on hepatic function. Adult (6-month-old) male spontaneously hypertensive rats (SHR) were fed a high-fat diet (60% fat) for four months to induce hepatic steatosis and mild heart failure. For the last two months, the rats were treated with empagliflozin (empa, 10 mg.kg-1.day-1 in the drinking water). Renal function and oral glucose tolerance test were analyzed in control (n=8), high-fat diet (SHR+HF, n=10), and empagliflozin-treated (SHR+HF+empa, n=9) SHR throughout the study. Metabolic parameters and echocardiography were evaluated at the end of the experiment. High-fat diet feeding increased body weight and visceral adiposity, liver triglyceride and cholesterol concentrations, and worsened glucose tolerance. Although the high-fat diet did not affect renal function, it significantly worsened cardiac function in a subset of SHR rats. Empagliflozin reduced body weight gain but not visceral fat deposition. It also improved glucose sensitivity and several metabolic parameters (plasma insulin, uric acid, and HDL cholesterol). In the liver, empagliflozin reduced ectopic lipid accumulation, lipoperoxidation, inflammation and pro-inflammatory HETEs, while increasing anti-inflammatory EETs. In addition, empagliflozin improved cardiac function (systolic, diastolic and pumping) independent of blood pressure. The results of our study suggest that hepatoprotection plays a decisive role in the beneficial effects of empagliflozin in preventing the progression of cardiac dysfunction induced by high-fat diet feeding.

Empagliflozin attenuates radiation-induced hematopoietic damage via NOX-4/ROS/p38 pathway

PURPOSE

Damage to the hematopoietic system and functional inhibition are severe consequences of radiation exposure. In this study, we have investigated the effect of empagliflozin on radiation-induced hematopoietic damage, with the aim of providing new preventive approach to such injuries.

METHODS AND MATERIALS

Mice were given 4 Gy total body irradiation (TBI) 1 h after the oral administration of empagliflozin, followed by the continuous administration of the same dose of empagliflozin for 6d, and then sacrificed on the 10th day after irradiation. The reactive oxygen species (ROS) levels in hematopoietic cells and their regulatory mechanisms were also been investigated. Colony forming unit granulocyte macrophage assay and bone marrow transplantation assays were performed to detect the function of the bone marrow cells.

KEY FINDINGS

Empagliflozin increased the cell viability, reduced ROS levels, and attenuated apoptosis in vitro after the bone marrow cells were exposed to 1 Gy radiation. Empagliflozin significantly attenuated ionizing radiation injuries to the hematopoietic system, increased the peripheral blood cell count, and enhanced the proportion and function of hematopoietic stem cells in mice exposed to 4 Gy TBI. These effects may be related to the NOX-4/ROS/p38 pathway-mediated suppression of MAPK in hematopoietic stem cells. Empagliflozin also influenced the expression of Nrf-2 and increased glutathione peroxidase activity, thereby promoting the clearance of reactive oxygen species. Furthermore, empagliflozin mitigated metabolic abnormalities by inhibiting the mammalian target of rapamycin.

SIGNIFICANCE

Our study has demonstrated that empagliflozin can reduce radiation-induced injury in hematopoietic stem cells. This finding suggests that empagliflozin is a promising novel agent for preventing radiation-induced damage to the hematopoietic system.

Empagliflozin alleviates the development of autoimmune myocarditis via inhibiting NF-κB-dependent cardiomyocyte pyroptosis

Autoimmune myocarditis, which falls within the broad spectrum of myocarditis, is characterized by an excessive inflammatory response in the heart, and can progress into dilated cardiomyopathy and irreversible heart failure in all possibility. However, effective clinical therapeutics are limited due to its complex inflammatory reactions. Empagliflozin (EMPA) has been previously demonstrated to possess anti-inflammatory properties. This study aimed to determine the improvement effects of EMPA on cardiac dysfunction under the condition of autoimmune myocarditis, and to further investigate the potential mechanisms. In vivo, all male Balb/c mice were randomly divided into four groups: control, experimental autoimmune myocarditis (EAM), EAM+EMPA and EMPA. In vitro, the effects of EMPA on IL-18-stimulated H9C2 cells were explored and the underlying molecular mechanisms were further determined. EMPA treatment significantly inhibited the development of autoimmune myocarditis, and mice treated with EMPA exhibited improved cardiac function compared with that in the EAM group, potentially through modulating pyroptosis of myocardium. Specifically, the NF-κB pathway was activated in the hearts of the EAM mice, which further activated NLRP3 inflammasome-dependent pyroptosis. EMPA treatment significantly inhibited such activation, thus alleviating inflammatory reactions in the context of EAM. Moreover, in vitro, we also observed that EMPA significantly inhibited pyroptosis of IL-18-stimulated H9C2 cells, and reduced nuclear translocation of NF-κB and degradation of activated IκBα. This work provides the first direct evidence that EMPA can inhibit myocardial inflammation and improve cardiac function in EAM mice, partly attributed to the drug-induced suppression of cardiomyocyte pyroptosis via disrupting the NF-κB pathway.

Efficacy and Safety of Sodium-Glucose Cotransporter-2 Inhibitors in Nondiabetic Patients with Chronic Kidney Disease: A Review of Recent Evidence

Background

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) were initially developed as glucose-lowering agents in patients with type-2 diabetes. However, available data from clinical trials and meta-analyses suggest that SGLT2i have pleiotropic benefits in reducing mortality and delaying the progression of chronic kidney disease (CKD) in both diabetic and nondiabetic patients. Thus, we herein review the current evidence regarding the efficacy and safety of SGLT2i in patients with nondiabetic CKD and appraise the recently reported clinical trials that might facilitate the management of CKD in routine clinical practice.

Summary

The benefits of SGLT2i on nondiabetic CKD are multifactorial and are mediated by a combination of mechanisms. The landmark DAPA-CKD trial revealed that dapagliflozin administered with renin-angiotensin system blockade drugs reduced the risk of a sustained decline (at least 50%) in the estimated glomerular filtration rate, end-stage kidney disease, or death from cardiorenal causes. The recent EMPA-KIDNEY trial showed that empagliflozin therapy led to a lower risk of progression of kidney disease or death from cardiovascular causes. These benefits were consistent in patients with and without diabetes. Moreover, a meta-analysis of DAPA-HF and EMPEROR-Reduced trials confirmed reductions in the combined risk of cardiovascular death or worsening heart failure including composite renal endpoint.

Key Messages

Considering the robust data available from DAPA-CKD, EMPA-KIDNEY, and other trials such as EMPEROR-Preserved, DIAMOND that included nondiabetic patients, it may be necessary to update current guidelines to include SGLT2i as a first-line therapy for CKD and reevaluate current CKD therapeutic approaches.

RNA-Seq transcriptome analysis of renal tissue from spontaneously hypertensive rats revealed renal protective effects of dapagliflozin, an inhibitor of sodium-glucose cotransporter 2

Hypertensive nephropathy (HTN) is a common complication of hypertension. Although various agents for treatment of hypertension exert significant effects, there is currently no effective treatment for hypertensive nephropathy. Sodium-glucose cotransporter 2 (SGLT2) inhibitors, such as dapagliflozin (DAPA), are a new class of hypoglycemic agents shown to improve the prognosis of patients with chronic kidney disease and diabetes mellitus. However, the mechanisms underlying the protective effects of DAPA remain unclear. RNA-sequencing (RNA-Seq)-based computational analysis was conducted to explore the transcriptomic changes to spontaneously hypertensive rats (SHRs) treated with DAPA for 8 weeks. Differentially expressed genes in SHRs were related to dysregulation of lipid metabolism, oxidation-reduction reaction, immunity and inflammation in HTN. Transcriptome analysis showed that 8 weeks of DAPA therapy exerted protective effects on the renal tissues of SHRs through the lysosomal, phagosomal, and autophagic pathways. VENN diagram analysis identified Zinc finger and BTB domain-containing 20 (Zbtb20) as the potential target of DAPA therapy. Consistent with the RNA-Seq findings, real-time quantitative PCR and immunohistochemical analyses revealed increased expression of Zbtb20 in the renal tissues of SHRs, whereas expression was decreased following 8 weeks of DAPA administration. The results of this study clarified the transcriptome signature of HTN and the beneficial effects of DAPA on renal tissues by alleviating dysregulation of metabolic processes and reducing inflammation.

RNA-Seq transcriptomic landscape profiling of spontaneously hypertensive rats treated with a sodium-glucose cotransporter 2 (SGLT2) inhibitor

BACKGROUND

Sodium-glucose co-transporter-2 inhibitor (SGLT2i) are antihyperglycemic medications that reduce cardiovascular disease (CVD) and improve chronic kidney disease prognosis in patients with diabetes mellitus. The specific impact of SGLT2i treatment on hypertensive individuals, however, remains to be established. This underscores the need for systematic efforts to profile the molecular landscape associated with SGLT2i administration.

METHODS

We conducted a detailed RNA-sequencing (RNA-Seq)-based exploration of transcriptomic changes in response to empagliflozin in eight different tissues (i.e., atrium, aorta, ventricle, white adipose, brown adipose, kidney, lung, and brain) from a male rat model of spontaneously hypertension. Corresponding computational analyses (i.e., clustering, differentially-expressed genes [DEG], and functional association) were performed to analyze these data. Blood pressure measurements, tissue staining studies and RT-qPCR were performed to validate our in silico findings.

RESULTS

We discovered that empagliflozin exerted potent transcriptomic effects on various tissues, most notably the kidney, white adipose, and lung in spontaneously hypertension rats (SHR). The functional enrichment of DEGs indicated that empagliflozin may regulate blood pressure, blood glucose and lipid homeostasis in SHR. Consistent with our RNA-Seq findings, immunohistochemistry and qPCR analyses revealed decreased renal expression of mitogen-activated protein kinase 10 (MAPK10) and decreased pulmonary expression of the proinflammatory factors Legumain and cathepsin S (CTSS) at 1 month of empagliflozin administration. Notably, immunofluorescence experiments showed increased expression of the AMP-activated protein kinases Prkaa1 and Prkaa2 in white adipose tissue of SHR following empagliflozin therapy. Furthermore, the transcriptomic signatures of the blood pressure-lowing effect by empagliflozin were experimentally validated in SHR.

CONCLUSIONS

This study provided an important resource of the effects of empagliflozin on various tissues of SHRs. We identified tissue-specific and tissue-enriched transcriptomic signatures, and uncovered the beneficial effects of empagliflozin on hypertension, weight gain and inflammatory response in validated experiments.

Associations of SGLT2 genetic polymorphisms with salt sensitivity, blood pressure changes and hypertension incidence in Chinese adults

Sodium-glucose cotransporter 2 (SGLT2) inhibitors lowers blood pressure (BP) and exert a salutary effect on the salt sensitivity of BP. This study aimed to examine the associations of SGLT2 genetic variants with salt sensitivity, longitudinal BP changes and the risk of incident hypertension in Baoji Salt-Sensitive Study. A total of 514 participants were recruited when the cohort was established in 2004, and 333 participants received a dietary intervention that consisted of a 3-day usual diet followed sequentially by a 7-day low-salt diet and a 7-day high-salt diet. The cohort was then followed up for 14 years to evaluate the longitudinal BP changes and development of hypertension. We found that SGLT2 SNP rs3813007 was significantly associated with the systolic BP (SBP) responses to the low-salt diet. Over the 14 years of follow-up, SNPs rs3116149 and rs3813008 were significantly associated with the longitudinal SBP changes, and SNPs rs3116149, rs3813008, rs3813007 in SGLT2 were significantly associated with incidence of hypertension. Furthermore, gene-based analyses revealed that SGLT2 was significantly associated with hypertension incidence. Our study suggests that SGLT2 genetic polymorphisms may be involved in salt sensitivity and development of hypertension.

Cardioprotective Effects of Sodium Glucose Cotransporter 2 Inhibition in Angiotensin II-Dependent Hypertension Are Mediated by the Local Reduction of Sympathetic Activity and Inflammation

The cardioprotective effects of sodium glucose cotrasponter 2 (SGLT2) inhibitors seem to be independent from the effects on glycemic control, through little-known mechanisms. In this study, we investigate whether the cardioprotective effects of empagliflozin, a SGLT2 inhibitor, may be associated with myocardial sympathetic activity and inflammatory cell infiltration in an experimental model of angiotensin II-dependent hypertension. Angiotensin II (Ang II), Ang II plus Empagliflozin, physiological saline, or physiological saline plus empagliflozin were administered to Sprague Dawley rats for two weeks. Blood pressure was measured by plethysmographic method. Myocardial hypertrophy and fibrosis were analysed by histomorphometry, and inflammatory cell infiltration and tyrosine hydroxylase expression, implemented as a marker of sympathetic activity, were evaluated by immunohistochemistry. Ang II increased blood pressure, myocardial hypertrophy, fibrosis, inflammatory infiltrates and tyrosine hydroxylase expression, as compared to the control group. Empagliflozin administration prevented the development of myocardial hypertrophy, fibrosis, inflammatory infiltrates and tyrosine hydroxylase overexpression in Ang II-treated rats, without affecting blood glucose and the Ang II-dependent increase in blood pressure. These data demonstrate that the cardioprotective effects of SGLT2 inhibition in Ang II-dependent hypertension may result from the myocardial reduction of sympathetic activity and inflammation and are independent of the modulation of blood pressure and blood glucose levels.

Empagliflozin Is Not Renoprotective in Non-Diabetic Rat Models of Chronic Kidney Disease

Gliflozins (sodium-glucose transporter-2 inhibitors) exhibited renoprotective effects not only in diabetic but also in non-diabetic patients with chronic kidney disease (CKD). Controversial results were reported in experimental non-diabetic models of CKD. Therefore, we examined empagliflozin effects in three CKD models, namely, in fawn-hooded hypertensive (FHH) rats, uninephrectomized salt-loaded (UNX + HS) rats, and in rats with Goldblatt hypertension (two-kidney, one-clip 2K1C) that were either untreated or treated with empagliflozin (10 mg/kg/day) for eight weeks. Plethysmography blood pressure (BP) was recorded weekly, and renal parameters (proteinuria, plasma urea, creatinine clearance, and sodium excretion) were analyzed three times during the experiment. At the end of the study, blood pressure was also measured directly. Markers of oxidative stress (TBARS) and inflammation (MCP-1) were analyzed in kidney and plasma, respectively. Body weight and visceral adiposity were reduced by empagliflozin in FHH rats, without a significant effect on BP. Experimentally induced CKD (UNX + HS and 2K1C) was associated with a substantial increase in BP and relative heart and kidney weights. Empagliflozin influenced neither visceral adiposity nor BP in these two models. Although empagliflozin increased sodium excretion, suggesting effective SGLT-2 inhibition, it did not affect diuresis in any experimental model. Unexpectedly, empagliflozin did not provide renoprotection because proteinuria, plasma urea, and plasma creatinine were not lowered by empagliflozin treatment in all three CKD models. In line with these results, empagliflozin treatment did not decrease TBARS or MCP-1 levels in either model. In conclusion, empagliflozin did not provide the expected beneficial effects on kidney function in experimental models of CKD.

Endothelial and Vascular Smooth Muscle Dysfunction in Hypertension

The development of essential hypertension involves several factors. Vascular dysfunction, characterized by endothelial dysfunction, low-grade inflammation and structural remodeling, plays an important role in the initiation and maintenance of essential hypertension. Although the mechanistic pathways by which essential hypertension develops are poorly understood, several pharmacological classes available on the clinical settings improve blood pressure by interfering in the cardiac output and/or vascular function. This review is divided in two major sections. The first section depicts the major molecular pathways as renin angiotensin aldosterone system (RAAS), endothelin, nitric oxide signalling pathway and oxidative stress in the development of vascular dysfunction. The second section describes the role of some pharmacological classes such as i) RAAS inhibitors, ii) dual angiotensin receptor-neprilysin inhibitors, iii) endothelin-1 receptor antagonists, iv) soluble guanylate cyclase modulators, v) phosphodiesterase type 5 inhibitors and vi) sodium-glucose cotransporter 2 inhibitors in the context of hypertension. Some classes are already approved in the treatment of hypertension, but others are not yet approved. However, due to their potential benefits these classes were included.

Empagliflozin Ameliorates Progression From Prediabetes to Diabetes and Improves Hepatic Lipid Metabolism: A Systematic Review

Diabetes mellitus (DM) and hepatic steatosis are two of the most common metabolic syndromes that affect the health of people globally. Empagliflozin (EMPA) is a promising drug of choice for the diabetic population. Recent studies have shown its beneficial effects not only on diabetic patients but also on patients suffering from cardiac, hepatic, neurological, or pancreatic anomalies. In this paper, we systematically searched electronic databases to compile literature that focuses on EMPA’s effect on the prediabetic population, diabetic population, and hepatic lipid metabolism. We focus on the mechanism of EMPA, specifically by which it increases insulin sensitivity and fat browning and reduces fat accumulation. Overall, we hypothesized that by its effect on weight loss and reducing inflammatory markers and insulin resistance (IR), EMPA decreases the rate of prediabetes to diabetes conversion. We concluded that by improving hepatic and serum triglyceride, decreasing visceral fat, and its positive impact on hepatic steatosis, the drug improves hepatic lipid metabolism. Further research should be done on this matter.

Beneficial Effects of Empagliflozin Are Mediated by Reduced Renal Inflammation and Oxidative Stress in Spontaneously Hypertensive Rats Expressing Human C-Reactive Protein

Gliflozins (inhibitors of sodium-glucose cotransporter 2) show many beneficial actions beyond their antidiabetic effects. The underlying mechanisms of these additional protective effects are still not well understood, especially under non-diabetic conditions. Therefore, we analyzed the effects of empagliflozin in young (3-month-old) and adult (12-month-old) male spontaneously hypertensive rats (SHR) expressing human C-reactive protein (CRP) in the liver. SHR-CRP rats are a non-diabetic model of metabolic syndrome, inflammation, and organ damage. Empagliflozin was given in a daily dose of 10 mg/kg body weight for 8 weeks. Both age groups of SHR-CRP rats treated with empagliflozin had lower body weight, decreased weight of fat depots, reduced ectopic fat accumulation in the liver and kidneys, and decreased levels of plasma insulin and β-hydroxybutyrate. Empagliflozin effectively reduced ectopic renal fat accumulation, and was associated with decreased inflammation. Exclusively in young rats, decreased microalbuminuria after empagliflozin treatment was accompanied by attenuated oxidative stress. In adult animals, empagliflozin also improved left ventricle function. In conclusion, in young animals, the beneficial renoprotective effects of empagliflozin could be ascribed to reduced lipid deposition in the kidney and the attenuation of oxidative stress and inflammation. In contrast, hepatic lipid metabolism was ameliorated in adult rats.

In a Prediabetic Model, Empagliflozin Improves Hepatic Lipid Metabolism Independently of Obesity and before Onset of Hyperglycemia

Recent studies suggest that treatment with SGLT-2 inhibitors can reduce hepatic lipid storage and ameliorate non-alcoholic fatty liver disease (NAFLD) development beyond their glycemic benefits. However, the exact mechanism involved is still unclear. We investigated the hepatic metabolic effect of empagliflozin (10 mg/kg/day for eight weeks) on the development of NAFLD and its complications using HHTg rats as a non-obese prediabetic rat model. Empagliflozin treatment reduced neutral triacylglycerols and lipotoxic diacylglycerols in the liver and was accompanied by significant changes in relative mRNA expression of lipogenic enzymes (Scd-1, Fas) and transcription factors (Srebp1, Pparγ). In addition, alterations in the gene expression of cytochrome P450 proteins, particularly Cyp2e1 and Cyp4a, together with increased Nrf2, contributed to the improvement of hepatic lipid metabolism after empagliflozin administration. Decreased circulating levels of fetuin-A improved lipid metabolism and attenuated insulin resistance in the liver and in peripheral tissues. Our results highlight the beneficial effect of empagliflozin on hepatic lipid metabolism and lipid accumulation independent of obesity, with the mechanisms understood to involve decreased lipogenesis, alterations in cytochrome P450 proteins, and decreased fetuin-A. These changes help to alleviate NAFLD symptoms in the early phase of the disease and before the onset of diabetes.