Empagliflozin Attenuates Vascular Calcification in Mice with Chronic Kidney Disease by Regulating the NFR2/HO-1 Anti-Inflammatory Pathway through AMPK Activation

The reno-protective effect of Empagliflozin against carbon tetrachloride (CCl4)-induced nephrotoxicity in mice halting JNK/MKK4/NRF2/NF-KB pathway

AIM

This study designed to evaluate the reno-protective effects of Empagliflozin (EMPA), a sodium-glucose co-transporter 2 (SGLT2) inhibitor, against carbon tetrachloride (CCl4)-induced nephrotoxicity in mice targeting JNK/MKK4/NRF2/NF-KB pathway.

METHODS

Male albino mice were given EMPA (10 mg/kg, orally) for 4 weeks prior to a single i.p. injection of 10 % CCl4 (20 ml/kg). Mice were sacrificed 48 h post CCl4 injection.

KEY FINDINGS

EMPA attenuated CCl4-induced renal injury, as reflected by a decrease in serum urea and creatinine levels, also preserved the histological integrity of kidney tissue. Theses reno-protective effects of EMPA can be mainly due to its 1. Antioxidant, (↑CAT, ↑SOD, ↑Nrf-2 and ↑ARE), 2. Anti-inflammatory (↓NF-κB and ↓TNF-α) and 3. Anti-apoptotic (↓Caspase-3) proprieties. EMPA also inhibited JNK/MKK4 signaling pathway, which plays a critical role in kidney damage.

CONCLUSION

These finding confirm the reno-protective effect of EMPA with a modulatory impact on JNK/MKK4/Nrf2/NF-κB signaling network; suggesting its therapeutic utility to minimize acute kidney injury (AKI) in clinical setting in the future.

Honokiol attenuates oxidative stress and vascular calcification via the upregulation of heme oxygenase-1 in chronic kidney disease

Vascular calcification (VC) is a common complication of chronic kidney disease (CKD), with oxidative stress identified as a key contributor to VC progression. Honokiol (HKL), a biphenolic compound derived from plants, has been found to be effective in treating various models of cardiovascular disease through the mitigation of oxidative stress. However, its effects on VC remain unexplored. To elucidate the effects of HKL on VC, a CKD rat model, a vitamin D3-overload-induced mouse model of vascular calcification, and a high-phosphate-induced human vascular smooth muscle cell (VSMC) calcification model were established. Calcification levels were assessed using alizarin red staining, calcium quantification, and western blotting of osteogenic markers. Oxidative stress was assessed by measuring reactive oxygen species. Furthermore, transcriptome sequencing was employed to identify molecules and pathways affected by HKL. HKL was found to significantly reduce calcification in both in vivo and in vitro models. It also mitigated oxidative stress induced by high phosphate in human VSMCs. Mechanistically, HKL upregulated heme oxygenase-1 (HMOX-1), thereby inhibiting oxidative stress and reducing calcification. Pharmacological inhibition of HMOX-1 counteracted the protective effect of HKL against vascular calcification. In summary, the findings suggest that HKL ameliorates VC by upregulating HMOX-1 and decreasing oxidative stress.

Impact of sodium-glucose cotransporter-2 inhibitors on pulmonary vascular cell function and arterial remodeling

Sodium-glucose cotransporter-2 (SGLT-2) inhibitors represent a cutting-edge class of oral antidiabetic therapeutics that operate through selective inhibition of glucose reabsorption in proximal renal tubules, consequently augmenting urinary glucose excretion and attenuating blood glucose levels. Extensive clinical investigations have demonstrated their profound cardiovascular efficacy. Parallel basic science research has elucidated the mechanistic pathways through which diverse SGLT-2 inhibitors beneficially modulate pulmonary vascular cells and arterial remodeling. Specifically, these inhibitors exhibit promising potential in enhancing pulmonary vascular endothelial cell function, suppressing pulmonary smooth muscle cell proliferation and migration, reversing pulmonary arterial remodeling, and maintaining hemodynamic equilibrium. This comprehensive review synthesizes current literature to delineate the mechanisms by which SGLT-2 inhibitors enhance pulmonary vascular cell function and reverse pulmonary remodeling, thereby offering novel therapeutic perspectives for pulmonary vascular diseases.

Enhanced hepatoprotective effects of empagliflozin and vitamin D dual therapy against metabolic dysfunction-associated steatohepatitis in mice by boosted modulation of metabolic, oxidative stress, and inflammatory pathways

Although single treatment with sodium-glucose cotransporter-2 inhibitors (SGLT2i) or vitamin D3 (VD3) inhibited metabolic dysfunction-associated steatohepatitis (MASH) development in diabetic patients, their combination has not been explored previously. Hence, this study investigated the hepatoprotective effects of SGLT2i (empagliflozin) and/or VD3 against MASH in type 2 diabetic mice. Forty Mice were assigned into negative (NC) and positive (PC) controls, SGLT2i, VD3, and SGLT2i + VD3 groups. All animals, except the NC group, received high-fructose/high-fat diet (8 weeks) followed by diabetes induction. Diabetic mice then received another cycle of high-fructose/high-fat diet (4 weeks) followed by 8 weeks of treatment (five times/week) with SGLT2i (5.1 mg/kg/day) and/or VD3 (410 IU/Kg/day). The PC group demonstrated hyperglycaemia, dyslipidaemia, elevated liver enzymes, and increased non-alcoholic fatty liver disease activity score (NAS) with fibrosis. Hepatic glucose transporting molecule (SGLT2) with lipogenesis (SREBP-1/PPARγ), oxidative stress (MDA/H2O2), inflammation (IL1β/IL6/TNF-α), fibrosis (TGF-β1/α-SMA), and apoptosis (TUNEL/Caspase-3) markers alongside the PI3K/AKT/mTOR pathway increased in the PC group. Conversely, hepatic insulin-dependent glucose transporter (GLUT4), lipolytic (PPARα/INSIG1), antioxidant (GSH/GPx1/SOD1/CAT), and anti-inflammatory (IL-10) molecules with the inhibitor of PI3K/AKT/mTOR pathway (PTEN) decreased in the PC group. Whilst SGLT2i monotherapy outperformed VD3, their combination showed the best attenuation of hyperglycaemia, dyslipidaemia, and fibrosis with the strongest modulation of hepatic glucose-transporting and lipid-regulatory molecules, PI3K/AKT/mTOR pathway, and markers of oxidative stress, inflammation, fibrosis, and apoptosis. This study is the first to reveal boosted hepatoprotection for SGLT2i and VD3 co-therapy against diabetes-induced MASH, possibly via enhanced metabolic control and modulation of hepatic PI3K/AKT/mTOR, anti-inflammatory, anti-oxidative, and anti-fibrotic pathways.

Dapagliflozin targets SGLT2/SIRT1 signaling to attenuate the osteogenic transdifferentiation of vascular smooth muscle cells

Vascular calcification is a complication that is frequently encountered in patients affected by atherosclerosis, diabetes, and chronic kidney disease (CKD), and that is characterized by the osteogenic transdifferentiation of vascular smooth muscle cells (VSMCs). At present, there remains a pressing lack of any effective therapies that can treat this condition. The sodium-glucose transporter 2 (SGLT2) inhibitor dapagliflozin (DAPA) has shown beneficial effects in cardiovascular disease. The role of this inhibitor in the context of vascular calcification, however, remains largely uncharacterized. Our findings revealed that DAPA treatment was sufficient to alleviate in vitro and in vivo osteogenic transdifferentiation and vascular calcification. Interestingly, our study demonstrated that DAPA exerts its anti-calcification effects on VSMCs by directly targeting SGLT2, with the overexpression of SGLT2 being sufficient to attenuate these beneficial effects. DAPA was also able to limit the glucose levels and NAD+/NADH ratio in calcified VSMCs, upregulating sirtuin 1 (SIRT1) in a caloric restriction (CR)-dependent manner. The SIRT1-specific siRNA and the SIRT1 inhibitor EX527 attenuated the anti-calcification effects of DAPA treatment. DAPA was also to drive SIRT1-mediated deacetylation and consequent degradation of hypoxia-inducible factor-1α (HIF-1α). The use of cobalt chloride and proteasome inhibitor MG132 to preserve HIF-1α stability mitigated the anti-calcification activity of DAPA. These analyses revealed that the DAPA/SGLT2/SIRT1 axis may therefore represent a viable novel approach to treating vascular calcification, offering new insights into how SGLT2 inhibitors may help prevent and treat vascular calcification.

Eucommia ulmoides extract regulates oxidative stress to maintain calcium homeostasis and improve diabetic osteoporosis

Diabetic osteoporosis (DOP) is a secondary disease that severely affects the health and quality of life of patients with diabetes mellitus. This study aimed to explore the bone protective effect of aqueous extract of Eucommia ulmoides (EUL) in DOP mice. DOP mice were established using a high-sugar, high-fat diet and streptozotocin (STZ) (35 mg/kg for three consecutive days), and the EUL aqueous extract (2.5 g/kg/day) was orally administered for 6 weeks. The serum levels of oxidative stress-related factors, calcium, and phosphorus were assessed using biochemical assays. The osteoprotective effect of EUL was assessed using micro-computer tomography, three-point bending assay, histological analysis, and immunoblotting. Quantitative real-time polymerase chain reaction and western blotting were performed to detect the expression levels of calcium transport channel factors in the kidney and small intestine tissues. Furthermore, the expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in the femur, kidney, and small intestine tissues were detected using western blotting and quantitative real-time polymerase chain reaction. EUL aqueous extract reduced blood glucose levels, increased body weight, and relieved symptoms in DOP mice (p < .05). It also increased bone mineral density, improved the bone microstructure, decreased the number of femoral osteoclasts, and increased the expression of femoral Runx2 and Bmp2 in DOP mice (p < .01). After 6 weeks of EUL aqueous extract administration, serum levels of SOD, CTA, calcium, and phosphorus were upregulated, whereas MDA levels were decreased (p < .01). The aqueous EUL extract also upregulated the expression of TRPV5, PMCA-1b, and CaBP-9 k in the kidney and small intestine of DOP mice (p < .01). Furthermore, the expression of Nrf2 and HO-1 in the kidney, small intestine, and femur tissues was increased (p < .01). EUL aqueous extract reduced blood glucose levels in DOP mice and regulated oxidative stress through the Nrf2/HO-1 pathway, thereby maintaining calcium homeostasis and ultimately improving bone quality. Our study suggested that EUL aqueous extract may be effective in the treatment of DOP.

Complex actions of sodium glucose transporter-2 inhibitors on lipids, calcific atherosclerosis, and bone density

PURPOSE OF REVIEW

Inhibitors of sodium-glucose cotransporter-2 (SGLT2) lower renal glucose reabsorption and, thus, are used to treat patients with type 2 diabetes mellitus. Clinical trials coincidentally showed that SGLT2 inhibitors also benefitted patients with heart failure. This review explores the impact of SGLT2 inhibitors on other aspects of cardiovascular disease and skeletal health.

RECENT FINDINGS

In some, but not all, clinical and preclinical studies, SGLT2 inhibitors are found to reduce serum levels of free fatty acids and triglycerides. Their effects on total and low-density lipoprotein cholesterol and cardiac function also vary. However, SGLT2 inhibitors reduce lipid accumulation in the liver, kidney, and heart, and alter expression of lipid metabolism genes. Effects on free fatty acid uptake in abdominal fat depots depend on the location of adipose tissue. In male, but not female, mice, SGLT2 inhibitors reduce the atherosclerotic lesions and aortic calcium deposition. With respect to skeletal health, recent literature has reported conflicting associations with the risks of fracture and amputation.

SUMMARY

Studies suggest that SGLT2 inhibitors reduce tissue lipid accumulation, and in a sex-dependent manner, atherosclerosis and vascular calcification. However, their effects on lipid levels and bone health are complex and remain to be established.

Empagliflozin attenuates epithelial-to-mesenchymal transition through senescence in peritoneal dialysis

Epithelial-to-mesenchymal transition (EMT) is considered as one of the senescence processes; reportedly, antisenescence therapies effectively reduce EMT. Some models have shown antisenescence effects with the use of sodium-glucose cotransporter 2 (SGLT2) inhibitor. Therefore, our study investigated the antisenescence effects of empagliflozin as an SGLT2 inhibitor in a peritoneal fibrosis model and their impact on EMT inhibition. For in vitro study, human peritoneal mesothelial cells (HPMCs) were isolated and grown in a 96-well plate. The cell media were exchanged with serum-free M199 medium with d-glucose, with or without empagliflozin. All animal experiments were carried out in male mice. Mice were randomly classified into three treatment groups based on peritoneal dialysis (PD) or empagliflozin. We evaluated changes in senescence and EMT markers in HPMCs and PD model. HPMCs treated with glucose transformed from cobblestone to spindle shape, resulting in EMT. Empagliflozin attenuated these morphological changes. Reactive oxygen species production, DNA damage, senescence, and EMT markers were increased by glucose treatment; however, cotreatment with glucose and empagliflozin attenuated these changes. For the mice with PD, an increase in thickness, collagen deposition, staining for senescence, or EMT markers of the parietal peritoneum was observed, which, however, was attenuated by cotreatment with empagliflozin. p53, p21, and p16 increased in mice with PD compared with those in the control group; however, these changes were decreased by empagliflozin. In conclusion, empagliflozin effectively attenuated glucose-induced EMT in HPMCs through a decrease in senescence. Cotreatment with empagliflozin improved peritoneal thickness and fibrosis in PD.NEW & NOTEWORTHY Epithelial-to-mesenchymal transition (EMT) is considered one of the senescence processes. Antisenescence therapies may effectively reduce EMT in peritoneal dialysis models. Human peritoneal mesothelial cells treated with glucose show an increase in senescence and EMT markers; however, empagliflozin attenuates these changes. Mice undergoing peritoneal dialysis exhibit increased senescence and EMT markers, which are decreased by empagliflozin. These findings suggest that empagliflozin may emerge as a novel strategy for prevention or treatment of peritoneal fibrosis.

Pathogenesis and Mechanism of Uremic Vascular Calcification

This review elucidates the modeling and mechanistic studies of vascular calcification in chronic kidney disease - mineral and bone disorder. In patients with chronic kidney disease, metabolic abnormalities in uremic toxins, including phosphate and indole sulfate, are closely associated with vascular calcification. Vitamin K, vascular circadian clock, and autophagy are also key factors involved in vascular calcification. Furthermore, communication between endothelial cells and smooth muscle cells also plays a pivotal role in the regulation of this process. Together, these factors accelerate vascular calcification progression and increase the risk of cardiovascular events. Therefore, timely intervention for vascular calcification is essential for patients with chronic kidney disease.

Empagliflozin alleviates atherosclerotic calcification by inhibiting osteogenic differentiation of vascular smooth muscle cells

SGLT-2 inhibitors, such as empagliflozin, have been shown to reduce the occurrence of cardiovascular events and delay the progression of atherosclerosis. However, its role in atherosclerotic calcification remains unclear. In this research, ApoE-/- mice were fed with western diet and empagliflozin was added to the drinking water for 24 weeks. Empagliflozin treatment significantly alleviated arterial calcification assessed by alizarin red and von kossa staining in aortic roots and reduced the lipid levels, while had little effect on body weight and blood glucose levels in ApoE-/- mice. In vitro studies, empagliflozin significantly inhibits calcification of primary vascular smooth muscle cells (VSMCs) and aortic rings induced by osteogenic media (OM) or inorganic phosphorus (Pi). RNA sequencing of VSMCs cultured in OM with or without empagliflozin showed that empagliflozin negatively regulated the osteogenic differentiation of VSMCs. And further studies confirmed that empagliflozin significantly inhibited osteogenic differentiation of VSMCs via qRT-PCR. Our study demonstrates that empagliflozin alleviates atherosclerotic calcification by inhibiting osteogenic differentiation of VSMCs, which addressed a critical need for the discovery of a drug-based therapeutic approach in the treatment of atherosclerotic calcification.

Editorial for the IJMS Special Issue on Sglt2 Inhibitors (Volume 2)

The goal of the second volume of this Special Issue was to build upon the success of the first one and to continue to highlight the ever-expanding list of pharmacological properties of the sodium/glucose co-transporter (SGLT) type 2 (SGLT2) inhibitor (SGLT2i) drug class (also known as gliflozins) [...].