Empagliflozin reverses obesity and insulin resistance through fat browning and alternative macrophage activation in mice fed a high-fat diet

SGLT2 Inhibitor Canagliflozin Reduces Visceral Adipose Tissue in db/db Mice by Modulating AMPK/KLF4 Signaling and Regulating Mitochondrial Dynamics to Induce Browning

Obesity is characterized by excessive accumulation of adipose tissue (mainly visceral). The morphology and function of mitochondria are crucial for regulating adipose browning and weight loss. Research suggests that the SGLT2 inhibitor canagliflozin may induce weight loss through an unknown mechanism, particularly targeting visceral adipose tissue. While Krueppel-Like Factor 4 (KLF4) is known to be essential for energy metabolism and mitochondrial function, its specific impact on visceral adipose tissue remains unclear. We administered canagliflozin to db/db mice for 8 weeks, or exposed adipocytes to canagliflozin for 24 hours. The expression levels of browning markers, mitochondrial dynamics, and KLF4 were assessed. Then we validated the function of KLF4 through overexpression in vivo and in vitro. Adenosine monophosphate-activated protein kinase (AMPK) agonists, inhibitors, and KLF4 si-RNA were employed to elucidate the relationship between AMPK and KLF4. The findings demonstrated that canagliflozin significantly decreased body weight in db/db mice and augmented cold-induced thermogenesis. Additionally, canagliflozin increased the expression of mitochondrial fusion-related factors while reducing the levels of fission markers in epididymal white adipose tissue. These consistent findings were mirrored in canagliflozin-treated adipocytes. Similarly, overexpression of KLF4 in both adipocytes and db/db mice yielded comparable results. In all, canagliflozin mitigates obesity in db/db mice by promoting the brown visceral adipocyte phenotype through enhanced mitochondrial fusion via AMPK/KLF4 signaling.

Regulation of macrophage polarization by targeted metabolic reprogramming for the treatment of lupus nephritis

Lupus nephritis (LN) is a severe and common manifestation of systemic lupus erythematosus (SLE) that is frequently identified with a poor prognosis. Macrophages play an important role in its pathogenesis. Different macrophage subtypes have different effects on lupus-affected kidneys. Based on their origin, macrophages can be divided into monocyte-derived macrophages (MoMacs) and tissue-resident macrophages (TrMacs). During nephritis, TrMacs develop a hybrid pro-inflammatory and anti-inflammatory functional phenotype, as they do not secrete arginase or nitric oxide (NO) when stimulated by cytokines. The infiltration of these mixed-phenotype macrophages is related to the continuous damage caused by immune complexes and exposure to circulating inflammatory mediators, which is an indication of the failure to resolve inflammation. On the other hand, MoMacs differentiate into M1 or M2 cells under cytokine stimulation. M1 macrophages are pro-inflammatory and secrete pro-inflammatory cytokines, while the M2 main phenotype is essentially anti-inflammatory and promotes tissue repair. Conversely, MoMacs undergo differentiation into M1 or M2 cells in response to cytokine stimulation. M1 macrophages are considered pro-inflammatory cells and secrete pro-inflammatory mediators, whereas the M2 main phenotype is primarily anti-inflammatory and promotes tissue repair. Moreover, based on cytokine expression, M2 macrophages can be further divided into M2a, M2b, and M2c phenotypes. M2a and M2c have anti-inflammatory effects and participate in tissue repair, while M2b cells have immunoregulatory and pro-inflammatory properties. Further, memory macrophages also have a role in the advancement of LN. Studies have demonstrated that the polarization of macrophages is controlled by multiple metabolic pathways, such as glycolysis, the pentose phosphate pathway, fatty acid oxidation, sphingolipid metabolism, the tricarboxylic acid cycle, and arginine metabolism. The changes in these metabolic pathways can be regulated by substances such as fish oil, polyenylphosphatidylcholine, taurine, fumaric acid, metformin, and salbutamol, which inhibit M1 polarization of macrophages and promote M2 polarization, thereby alleviating LN.

Glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter 2 inhibitors, anti-diabetic drugs in heart failure and cognitive impairment: potential mechanisms of the protective effects

Heart failure and cognitive impairment emerge as public health problems that need to be addressed due to the aging global population. The conditions that often coexist are strongly related to advancing age and multimorbidity. Epidemiological evidence indicates that cardiovascular disease and neurodegenerative processes shares similar aspects, in term of prevalence, age distribution, and mortality. Type 2 diabetes increasingly represents a risk factor associated not only to cardiometabolic pathologies but also to neurological conditions. The pathophysiological features of type 2 diabetes and its metabolic complications (hyperglycemia, hyperinsulinemia, and insulin resistance) play a crucial role in the development and progression of both heart failure and cognitive dysfunction. This connection has opened to a potential new strategy, in which new classes of anti-diabetic medications, such as glucagon-like peptide-1 receptor (GLP-1R) agonists and sodium-glucose cotransporter 2 (SGLT2) inhibitors, are able to reduce the overall risk of cardiovascular events and neuronal damage, showing additional protective effects beyond glycemic control. The pleiotropic effects of GLP-1R agonists and SGLT2 inhibitors have been extensively investigated. They exert direct and indirect cardioprotective and neuroprotective actions, by reducing inflammation, oxidative stress, ions overload, and restoring insulin signaling. Nonetheless, the specificity of pathways and their contribution has not been fully elucidated, and this underlines the urgency for more comprehensive research.

Narrative Review of Immunomodulatory and Anti-inflammatory Effects of Sodium-Glucose Cotransporter 2 Inhibitors: Unveiling Novel Therapeutic Frontiers

Sodium-glucose cotransporter 2 inhibitors (SGLT2 inhibitors) have evolved from their initial role as antidiabetic drugs to garner recognition for their remarkable cardio-protective and reno-protective attributes. They have become a crucial component of therapeutic guidelines for congestive heart failure and proteinuric chronic kidney disease (CKD). These benefits extend beyond glycemic control, because improvements in cardiovascular and renal outcomes occur swiftly. Recent studies have unveiled the immunomodulatory properties of SGLT2 inhibitors; thus, shedding light on their potential to influence the immune system and inflammation. This comprehensive review explores the current state of knowledge regarding the impact of SGLT2 inhibitors on the immune system and inflammation, focusing on preclinical and clinical evidence. The review delves into their antiinflammatory and immunomodulating effects, offering insights into clinical implications, and exploring emerging research areas related to their prospective immunomodulatory impact.

Research advances in the anti-inflammatory effects of SGLT inhibitors in type 2 diabetes mellitus

Diabetes mellitus is one of the most significant global burden diseases. It is well established that a chronic, systemic, low-grade inflammatory condition is strongly correlated with type 2 diabetes mellitus (T2D) and the development of target-organ damage (TOD). Sodium-glucose cotransporter inhibitors (SGLTis), novel oral drugs for the treatment of diabetes, act mainly by reducing glucose reabsorption in proximal renal tubules and/or the intestine. Several high-quality clinical trials and large observational studies have revealed that SGLTis significantly improve cardiovascular and renal outcomes in T2D patients. Increasing evidence suggests that this is closely related to their anti-inflammatory properties, which are mainly manifested by a reduction in plasma concentrations of inflammatory biomarkers. This review analyses the potential mechanisms behind the anti-inflammatory effects of SGLTis in diabetes and presents recent evidence of their therapeutic efficacy in treating diabetes and related TOD.

Dapagliflozin promotes browning of white adipose tissue through the FGFR1-LKB1-AMPK signaling pathway

BACKGROUND

Obesity is associated with a wide variety of metabolic disorders that impose significant burdens on patients and society. The "browning" phenomenon in white adipose tissue (WAT) has emerged as a promising therapeutic strategy to combat metabolic disturbances. However, though the anti-diabetic drug dapagliflozin (DAPA) is thought to promote "browning," the specific mechanism of this was previously unclear.

METHODS

In this study, C57BL/6 J male mice were used to establish an obesity model by high-fat diet feeding, and 3T3-L1 cells were used to induce mature adipocytes and to explore the role and mechanism of DAPA in "browning" through a combination of in vitro and in vivo experiments.

RESULTS

The results show that DAPA promotes WAT "browning" and improves metabolic disorders. Furthermore, we discovered that DAPA activated "browning" through the fibroblast growth factor receptors 1-liver kinase B1-adenosine monophosphate-activated protein kinase signaling pathway.

CONCLUSION

These findings provide a rational basis for the use of DAPA in treating obesity by promoting the browning of white adipose tissue.

Unraveling the complex roles of macrophages in obese adipose tissue: an overview

Macrophages, a heterogeneous population of innate immune cells, exhibit remarkable plasticity and play pivotal roles in coordinating immune responses and maintaining tissue homeostasis within the context of metabolic diseases. The activation of inflammatory macrophages in obese adipose tissue leads to detrimental effects, inducing insulin resistance through increased inflammation, impaired thermogenesis, and adipose tissue fibrosis. Meanwhile, adipose tissue macrophages also play a beneficial role in maintaining adipose tissue homeostasis by regulating angiogenesis, facilitating the clearance of dead adipocytes, and promoting mitochondrial transfer. Exploring the heterogeneity of macrophages in obese adipose tissue is crucial for unraveling the pathogenesis of obesity and holds significant potential for targeted therapeutic interventions. Recently, the dual effects and some potential regulatory mechanisms of macrophages in adipose tissue have been elucidated using single-cell technology. In this review, we present a comprehensive overview of the intricate activation mechanisms and diverse functions of macrophages in adipose tissue during obesity, as well as explore the potential of drug delivery systems targeting macrophages, aiming to enhance the understanding of current regulatory mechanisms that may be potentially targeted for treating obesity or metabolic diseases.

Interleukin-33/serum stimulation-2 pathway: Regulatory mechanisms and emerging implications in immune and inflammatory diseases

Interleukin (IL)- 33, a nuclear factor and pleiotropic cytokine of the IL-1 family, is gaining attention owing to its important role in chronic inflammatory and autoimmune diseases. This review extends our knowledge of the effects exerted by IL-33 on target cells by binding to its specific receptor serum stimulation-2 (ST2). Depending on the tissue context, IL-33 performs multiple functions encompassing host defence, immune response, initiation and amplification of inflammation, tissue repair, and homeostasis. The levels and activity of IL-33 in the body are controlled by complex IL-33-targeting regulatory pathways. The unique temporal and spatial expression patterns of IL-33 are associated with host homeostasis and the development of immune and inflammatory disorders. Therefore, understanding the origin, function, and processes of IL-33 under various conditions is crucial. This review summarises the regulatory mechanisms underlying the IL-33/ST2 signalling axis and its potential role and clinical significance in immune and inflammatory diseases, and discusses the current complex and conflicting findings related to IL-33 in host responses.

Sweet triterpenoid glycoside from Cyclocarya paliurus ameliorates obesity-induced insulin resistance through inhibiting the TLR4/NF-κB/NLRP3 inflammatory pathway

Our prophase studies have manifested that the sweet triterpenoid glycoside from the leaves of Cyclocarya paliurus (CPST) effectively improved the disorders of glucolipid metabolism in vitro and in patients. The current purpose was to further detect its mechanisms involved. The results demonstrated that CPST could ameliorate high-fat diet (HFD)-induced insulin resistance (IR), which was linked to reducing HFD-induced mice's body weight, serum glucose (GLUO), triglyceride (TG), total cholesterol (T-CHO) and low-density lipoprotein cholesterol (LDL-C), lowering the area under the oral glucose tolerance curve and insulin tolerance, elevating the percentage of brown adipose, high-density lipoprotein cholesterol (HDL-C), reducing fat droplets of adipocytes in interscapular brown adipose tissue (iBAT) and cross-sectional area of adipocytes. Further studies manifested that CPST obviously downregulated TLR4, MyD88, NLRP3, ASC, caspase-1, cleased-caspase-1, IL-18, IL-1β, TXNIP, and GSDMD protein expressions and p-NF-кB/NF-кB ratio in iBAT. These aforementioned findings demonstrated that CPST ameliorated HFD induced IR by regulating TLR4/NF-κB/NLRP3 signaling pathway, which in turn enhancing insulin sensitivity and glucose metabolism.

The anti-inflammatory and immunological properties of SGLT-2 inhibitors

BACKGROUND

Sodium-glucose cotransporter-2 inhibitors (SGLT-2i) are antidiabetic oral drugs that act on proximal renal tubules promoting renal glucose excretion. Although SGLT-2i belong to the class of hypoglycemic agents, in the last years great interest has emerged in studying their pleiotropic effects, beyond their ability to lower glucose levels.

PURPOSE

In this review we are describing the anti-inflammatory and immunological properties of SGLT-2i; furthermore, we are addressing how the mechanisms associated with the aforementioned anti-inflammatory properties may contribute to the beneficial effects of SGLT-2i in diabetes.

METHODS

A systematic search was undertaken for studies related the properties of SGLT-2i in reducing the inflammatory milieu of acute and chronic disease by acting on the immune system, independently by glycemia.

RESULTS

Recently, some data described the anti-inflammatory and immunological properties of SGLT-2 in both pre-clinical and clinical studies. Numerous data confirmed the cardio- and -renal protective effects of SGLT-2i in patients with heart failure and kidney diseases, with or without diabetes.

CONCLUSIONS

SGLT-2i are promising drugs with anti-inflammatory and immunological properties. Despite the mechanism of action of SGLT-2i is not fully understood, these drugs demonstrated anti-inflammatory effects, which may help in keeping under control the variety of complications associated with diabetes.

Biomarkers for Assessing Non-Alcoholic Fatty Liver Disease in Patients with Type 2 Diabetes Mellitus on Sodium-Glucose Cotransporter 2 Inhibitor Therapy

In the current modern era of unhealthy lifestyles, non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver disease and has become a serious global health problem. To date, there is no approved pharmacotherapy for the treatment of NAFLD, and necessary lifestyle changes such as weight loss, diet, and exercise are usually not sufficient to manage this disease. Patients with type 2 diabetes mellitus (T2DM) have a significantly higher risk of developing NAFLD and vice versa. Sodium-glucose cotransporter 2 (SGLT2) inhibitors are antidiabetic agents that have recently been approved for two other indications: chronic kidney disease and heart failure in diabetics and non-diabetics. They are also emerging as promising new agents for NAFLD treatment, as they have shown beneficial effects on hepatic inflammation, steatosis, and fibrosis. Studies in animals have reported favorable effects of SGLT2 inhibitors, and studies in patients also found positive effects on body mass index (BMI), insulin resistance, glucose levels, liver enzymes, apoptosis, and transcription factors. There are some theories regarding how SGLT2 inhibitors affect the liver, but the exact mechanism is not yet fully understood. Therefore, biomarkers to evaluate underlying mechanisms of action of SGLT2 inhibitors on the liver have now been scrutinized to assess their potential as a future in-label therapy for NAFLD. In addition, finding suitable non-invasive biomarkers could be helpful in clinical practice for the early detection of NAFLD in patients. This is crucial for a positive disease outcome. The aim of this review is to provide an overview of the most recent findings on the effects of SGLT2 inhibitors on NAFLD biomarkers and the potential of SGLT2 inhibitors to successfully treat NAFLD.

Effects of SGLT2 inhibitor administration on blood glucose level and body weight in type 1 diabetes rat model

The prevalence of diabetes worldwide is increasing and 629 million people are projected to have diabetes by 2045, and the most significant burden of the disease being concentrated in low- and middle-income countries (LMICs). Type 2 diabetes is mainly treated with insulin adjunctive therapies such as metformin to improve insulin sensitivity and sodium-glucose co-transporter 2 (SGLT2) inhibitors to lower blood glucose levels. However, there was limited study on the application of SGLT2 inhibitors on type 1 diabetes, particularly empagliflozin. Therefore, this study aimed to determine the effect of SGLT2 inhibitors on blood glucose levels and body weights in a rat model of type 1 diabetes. To mimic type 1 diabetes, the rats were injected with streptozotocin 60 mg intra-peritoneally. Twenty-four rat models were randomly divided into four groups: normal rat group (negative control), untreated diabetic rat group (positive control), type 1 diabetic rats treated with metformin, and type 1 diabetic rats treated with empagliflozin. Blood glucose levels and body weight were recorded before and after induced with streptozotocin and on weeks 4, 6, 8 and 10 of the treatment with anti-diabetic drugs. This study found that the blood glucose levels before and after treatment significantly decreased in all groups (p<0.05), except in the negative control group. Similar results were observed in body weight of the rats, which all groups experienced weight loss, except the negative control. These results suggested that apart from being used in type 2 diabetes, SGLT2 inhibitors may also be used as a treatment for type 1 diabetes.

Insights into the Role of Plasmatic and Exosomal microRNAs in Oxidative Stress-Related Metabolic Diseases

A common denominator of metabolic diseases, including type 2 diabetes Mellitus, dyslipidemia, and atherosclerosis, are elevated oxidative stress and chronic inflammation. These complex, multi-factorial diseases are caused by the detrimental interaction between the individual genetic background and multiple environmental stimuli. The cells, including the endothelial ones, acquire a preactivated phenotype and metabolic memory, exhibiting increased oxidative stress, inflammatory gene expression, endothelial vascular activation, and prothrombotic events, leading to vascular complications. There are different pathways involved in the pathogenesis of metabolic diseases, and increased knowledge suggests a role of the activation of the NF-kB pathway and NLRP3 inflammasome as key mediators of metabolic inflammation. Epigenetic-wide associated studies provide new insight into the role of microRNAs in the phenomenon of metabolic memory and the development consequences of vessel damage. In this review, we will focus on the microRNAs related to the control of anti-oxidative enzymes, as well as microRNAs related to the control of mitochondrial functions and inflammation. The objective is the search for new therapeutic targets to improve the functioning of mitochondria and reduce oxidative stress and inflammation, despite the acquired metabolic memory.

Novel Antidiabetic Agents and Their Effects on Lipid Profile: A Single Shot for Several Cardiovascular Targets

Type-2 diabetes mellitus (DM) represents one of the most important risk factors for cardiovascular diseases (CVD). Hyperglycemia and glycemic variability are not the only determinant of the increased cardiovascular (CV) risk in diabetic patients, as a frequent metabolic disorder associated with DM is dyslipidemia, characterized by hypertriglyceridemia, decreased high-density lipoprotein (HDL) cholesterol levels and a shift towards small dense low-density lipoprotein (LDL) cholesterol. This pathological alteration, also called diabetic dyslipidemia, represents a relevant factor which could promotes atherosclerosis and subsequently an increased CV morbidity and mortality. Recently, the introduction of novel antidiabetic agents, such as sodium glucose transporter-2 inhibitors (SGLT2i), dipeptidyl peptidase-4 inhibitors (DPP4i) and glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1 RAs), has been associated with a significant improvement in CV outcomes. Beyond their known action on glycemia, their positive effects on the CV system also seems to be related to an ameliorated lipidic profile. In this context, this narrative review summarizes the current knowledge regarding these novel anti-diabetic drugs and their effects on diabetic dyslipidemia, which could explain the provided global benefit to the cardiovascular system.

The Role of Macrophages in Atherosclerosis: Pathophysiologic Mechanisms and Treatment Considerations

Atherosclerotic diseases are a leading cause of morbidity and mortality worldwide, despite the recent diagnostic and therapeutic advances. A thorough understanding of the pathophysiologic mechanisms is thus essential to improve the care of affected individuals. Macrophages are crucial mediators of the atherosclerotic cascade, but their role has not been fully elucidated. The two main subtypes, tissue-resident and monocyte-derived macrophages, have distinct functions that contribute to atherosclerosis development or regression. Since polarization of macrophages to an M2 phenotype and induction of macrophage autophagy have been demonstrated to be atheroprotective, targeting these pathways could represent an appealing approach. Interestingly, macrophage receptors could act as drug targets, as seen in recent experimental studies. Last but not least, macrophage-membrane-coated carriers have been investigated with encouraging results.

Perivascular adipose tissue in vascular pathologies-a novel therapeutic target for atherosclerotic disease?

Most blood vessels are surrounded by adipose tissues known as perivascular adipose tissue (PVAT). Emerging experimental data have implicated the potential involvement of PVAT in the pathogenesis of cardiovascular disease: PVAT might be a source of inflammatory mediators under pathological conditions such as metabolic disorders, chronic inflammation, and aging, leading to vascular pathologies, while having vasculo-protective roles in a healthy state. PVAT has been also gaining attention in human disease conditions. Recent integrative omics approaches have greatly enhanced our understanding of the molecular mechanisms underlying the diverse functions of PVAT. This review summarizes recent progress in PVAT research and discusses the potential of PVAT as a target for the treatment of atherosclerosis.

Adipose tissue macrophages as potential targets for obesity and metabolic diseases

Macrophage infiltration into adipose tissue is a key pathological factor inducing adipose tissue dysfunction and contributing to obesity-induced inflammation and metabolic disorders. In this review, we aim to present the most recent research on macrophage heterogeneity in adipose tissue, with a focus on the molecular targets applied to macrophages as potential therapeutics for metabolic diseases. We begin by discussing the recruitment of macrophages and their roles in adipose tissue. While resident adipose tissue macrophages display an anti-inflammatory phenotype and promote the development of metabolically favorable beige adipose tissue, an increase in pro-inflammatory macrophages in adipose tissue has negative effects on adipose tissue function, including inhibition of adipogenesis, promotion of inflammation, insulin resistance, and fibrosis. Then, we presented the identities of the newly discovered adipose tissue macrophage subtypes (e.g. metabolically activated macrophages, CD9+ macrophages, lipid-associated macrophages, DARC+ macrophages, and MFehi macrophages), the majority of which are located in crown-like structures within adipose tissue during obesity. Finally, we discussed macrophage-targeting strategies to ameliorate obesity-related inflammation and metabolic abnormalities, with a focus on transcriptional factors such as PPARγ, KLF4, NFATc3, and HoxA5, which promote macrophage anti-inflammatory M2 polarization, as well as TLR4/NF-κB-mediated inflammatory pathways that activate pro-inflammatory M1 macrophages. In addition, a number of intracellular metabolic pathways closely associated with glucose metabolism, oxidative stress, nutrient sensing, and circadian clock regulation were examined. Understanding the complexities of macrophage plasticity and functionality may open up new avenues for the development of macrophage-based treatments for obesity and other metabolic diseases.

Tofogliflozin, a sodium-glucose cotransporter 2 inhibitor, improves pulmonary vascular remodeling due to left heart disease in mice

BACKGROUND

Group 2 pulmonary hypertension (PH) represents PH caused by left heart disease (PH-LHD). LHD induces left-sided filling and PH, finally leading to pulmonary vascular remodeling. Tofogliflozin (TOFO) is a sodium-glucose cotransporter 2 (SGLT2) inhibitor used in the treatment of diabetes. Recent studies have shown that SGLT2 inhibitors have beneficial effects on heart failure, but the effects of SGLT2 inhibitors on PH-LHD remain unclear. We hypothesized that TOFO has protective effects against pulmonary vascular remodeling in PH-LHD mice.

METHODS

We generated two murine models of PH-LHD: a transverse aortic constriction (TAC) model; and a high-fat diet (HFD) model. C57BL/6J mice were subjected to TAC and treated with TOFO (3 mg/kg/day) for 3 weeks. AKR/J mice were fed HFD and treated with TOFO (3 mg/kg/day) for 20 weeks. We then measured physical data and right ventricular systolic pressure (RVSP) and performed cardiography. Human pulmonary artery smooth muscle cells (PASMCs) were cultured and treated with TOFO.

RESULTS

Mice treated with TOFO demonstrated increased urine glucose levels. TAC induced left ventricular hypertrophy and increased RVSP. TOFO treatment improved RVSP. HFD increased body weight (BW) and RVSP compared with the normal chow group. TOFO treatment ameliorated increases in BW and RVSP induced by HFD. Moreover, PASMCs treated with TOFO showed suppressed migration.

CONCLUSIONS

TOFO treatment ameliorated right heart overload and pulmonary vascular remodeling for PH-LHD models, suggesting that SGLT2 inhibitors are effective for treating PH-LHD.

Empagliflozin protects mice against diet-induced obesity, insulin resistance and hepatic steatosis

AIMS/HYPOTHESIS

Sodium-glucose cotransporter 2 (SGLT2) inhibitors are widely used in the treatment of type 2 diabetes, heart failure and chronic kidney disease. Their role in the prevention of diet-induced metabolic deteriorations, such as obesity, insulin resistance and fatty liver disease, has not been defined yet. In this study we set out to test whether empagliflozin prevents weight gain and metabolic dysfunction in a mouse model of diet-induced obesity and insulin resistance.

METHODS

C57Bl/6 mice were fed a western-type diet supplemented with empagliflozin (WDE) or without empagliflozin (WD) for 10 weeks. A standard control diet (CD) without or with empagliflozin (CDE) was used to control for diet-specific effects. Metabolic phenotyping included assessment of body weight, food and water intake, body composition, hepatic energy metabolism, skeletal muscle mitochondria and measurement of insulin sensitivity using hyperinsulinaemic-euglycaemic clamps.

RESULTS

Mice fed the WD were overweight, hyperglycaemic, hyperinsulinaemic and insulin resistant after 10 weeks. Supplementation of the WD with empagliflozin prevented these metabolic alterations. While water intake was significantly increased by empagliflozin supplementation, food intake was similar in WDE- and WD-fed mice. Adipose tissue depots measured by MRI were significantly smaller in WDE-fed mice than in WD-fed mice. Additionally, empagliflozin supplementation prevented significant steatosis found in WD-fed mice. Accordingly, hepatic insulin signalling was deteriorated in WD-fed mice but not in WDE-fed mice. Empagliflozin supplementation positively affected size and morphology of mitochondria in skeletal muscle in both CD- and WD-fed mice.

CONCLUSIONS/INTERPRETATION

Empagliflozin protects mice from diet-induced weight gain, insulin resistance and hepatic steatosis in a preventative setting and improves muscle mitochondrial morphology independent of the type of diet.

Celastrol confers ferroptosis resistance via AKT/GSK3β signaling in high-fat diet-induced cardiac injury

Obesity-induced cardiac dysfunction is a severe global disease associated with high dietary fat intake, and its pathogenesis includes inflammation, oxidative stress, and ferroptosis. Celastrol (Cel) is a bioactive compound isolated from the herb Tripterygium wilfordii, which has a protective influence on cardiovascular diseases. In this study, the role of Cel in obesity-induced ferroptosis and cardiac injury was investigated. We found that Cel alleviated ferroptosis induced by Palmitic acid (PA), exhibiting a decrease in the LDH, CK-MB, Ptgs2, and Lipid Peroxidation levels. After cardiomyocytes were treated with additional LY294002 and LiCl, Cel exerted its protective effect through increased AKT/GSK3β phosphorylation and decreased level of lipid peroxidation and Mitochondrial ROS. The systolic left ventricle (LV) dysfunction of obese mice was alleviated via ferroptosis inhibition by elevated p-GSK3β and decreased Mitochondrial ROS under Cel treatment. Moreover, mitochondrial anomalies included swelling and distortion in the myocardium which was relieved with Cel. In conclusion, our results demonstrate that ferroptosis resistance with Cel under HFD conditions targets AKT/GSK3β signaling, which provides novel therapeutic strategies in obesity-induced cardiac injury.

Metformin, Empagliflozin, and Their Combination Modulate Ex-Vivo Macrophage Inflammatory Gene Expression

Type-2 Diabetes Mellitus is a complex, chronic illness characterized by persistent high blood glucose levels. Patients can be prescribed anti-diabetes drugs as single agents or in combination depending on the severity of their condition. Metformin and empagliflozin are two commonly prescribed anti-diabetes drugs which reduce hyperglycemia, however their direct effects on macrophage inflammatory responses alone or in combination are unreported. Here, we show that metformin and empagliflozin elicit proinflammatory responses on mouse bone-marrow-derived macrophages with single agent challenge, which are modulated when added in combination. In silico docking experiments suggested that empagliflozin can interact with both TLR2 and DECTIN1 receptors, and we observed that both empagliflozin and metformin increase expression of Tlr2 and Clec7a. Thus, findings from this study suggest that metformin and empagliflozin as single agents or in combination can directly modulate inflammatory gene expression in macrophages and upregulate the expression of their receptors.

Knowledge mapping of interleukin-33: a bibliometric study

Interleukin-33 (IL-33) is a member of the IL-1 family of cytokines. IL-33 is associated with the expression of tissue damage or necrosis after increasing and being released into the cell, it influences the suppression of tumorigenicity 2 (ST2) receptor expression of a variety of immune cells (including mast cells and type 2 congenital lymphocytes). Furthermore, during type 2 innate immune reactions and allergic inflammation IL-33 plays a central role in immune amplification and "alarming"; thus, regulating immune responeses. IL-33 is closely related to inflammation-related diseases such as allergic diseases, autoimmune diseases, infectious diseases, and tumors. It is essential in maintaining tissue homeostasis, eliminating inflammation, and repairing tissue damage. We searched the Web of Science Core Collection (WoSCC) database for relevant publications on IL-33 from 2005 to 2021 and screened them according to specific inclusion criteria. A total of 2626 articles were included in our analysis. Using Microsoft Excel 2019 (Redmond, WA), VOSviewer 1.6.11 (The Centre for Science and Technology Studies, CWTS), and Citespace5.8. R2 (Drexel University, Philadelphia, PA) were used for data processing and visualization. Countries/regions, journals, authors, co-cited references, and keywords were analyzed. We discovered that IL-33 plays an important role as a cytokine in numerous diseases, especially allergic diseases. Studying its mechanism of action is of great importance for developing novel drugs and therapeutics.

Influence of Sodium-Glucose Cotransporter-2 Inhibitors on Plasma Adiponectin in Patients with Type 2 Diabetes: A Meta-Analysis of Randomized Controlled Trials

The influence of sodium-glucose cotransporter-2 (SGLT-2) inhibitors on plasma adiponectin remains not comprehensively evaluated. We performed a meta-analysis to systematically evaluate the effect of SGLT2 inhibitors on plasma level of adiponectin in patients with type 2 diabetes mellitus (T2DM). Randomized controlled trials comparing SGLT-2 inhibitors with non-active controls on plasma adiponectin in T2DM patients were retrieved by search of the Medline (PubMed), Embase, and CENTER (Cochrane Library) databases from inception to April 5, 2022. Study characteristics and outcome data were independently extracted by two authors. A random-effect model by incorporating the potential between-study heterogeneity was used to combine the results. Fourteen studies with 2142 patients contributed to the meta-analysis. Compared to placebo, SGLT-2 inhibitors significantly increased plasma adiponectin [standard mean difference (SMD): 0.35, 95% CI: 0.24 to 0.46, p<0.001] with mild heterogeneity (I2=19%). Predefined subgroup analyses suggested that tofogliflozin (SMD: 0.37, p<0.001), luseogliflozin (SMD: 0.51, p<0.001), and ipragliflozin (SMD: 0.34, p<0.001) were associated with increased adiponectin, but not for dapagliflozin (SMD: 0.14, p 0.26). In addition, SGLT-2 inhibitors were associated with increased adiponectin in studies from Asia (SMD: 0.42, p<0.001), but not in studies from the western countries (SMD: 0.16, p 0.17). Moreover, the increment of adiponectin was more significant in patients with body mass index (BMI)<30 kg/m2 (SMD: 0.46, p<0.001) than that in patients with BMI≤30 kg/m2 (SMD: 0.19, p 0.02, p for subgroup difference 0.01). In conclusion, SGLT-2 inhibitors could significantly increase plasma adiponectin as compared with placebo in T2DM patients.

The effect of sodium-glucose cotransporter 2 inhibitors on biomarkers of inflammation: A systematic review and meta-analysis of randomized controlled trials

Aims: Inflammatory biomarkers may play vital roles in the pathophysiology of diabetes and diabetic cardiorenal complications. Sodium-glucose cotransporter-2 (SGLT2) inhibitors have a potential cardiovascular and renal protective effect in type 2 diabetes. The aim of this meta-analysis was to quantify the effects of SGLT2 inhibitors on biomarkers of inflammation in randomized controlled trials (RCTs). Methods: PubMed, Cochrane Library, EMBASE, and Web of Science were searched for eligible RCTs of adults with type 2 diabetes (T2D) with no time limit (updated to 12 October 2022). The biomarkers selected included C-reactive protein (CRP), interleukin-6, tumor necrosis factor-alpha, leptin, adiponectin, ferritin, plasminogen activator inhibitor (PAI)-1, and vascular cell adhesion molecule-1. Data were analyzed using a random-effect model in Review Manager 5.4. Results: Thirty-four studies with 6,261 patients (68.6% male) were eligible for this meta-analysis. The mean age of the participants was 62.57(±11.13) years old, and the median treatment duration length with follow-up was 24 weeks. Generally, the included trials were of good methodological quality. The meta-analysis revealed that ferritin levels were significantly reduced in SGLT2 inhibitor treatment groups versus placebo or standard diabetes therapies (SMD: -1.21; 95% CI: -1.91, -0.52, p < 0.001). The effects of CRP (SMD: 0.25; 95% CI: -0.47, -0.03, p = 0.02) and leptin (SMD: -0.22; 95% CI: -0.43, -0.01, p = 0.04) were reduced, and the effects of adiponectin were improved (SMD: 0.28; 95% CI: 0.15, 0.41, p < 0.001) in placebo-controlled studies. PAI-1 levels were significantly reduced in studies controlled for diabetes therapies (SMD: -0.38; 95% CI: -0.61, -0.15, p = 0.001). Conclusion: This analysis provides strong evidence supporting anti-inflammatory effects of SGLT2 inhibitors in T2D subjects. The mechanisms and possible targets for the inflammation reducing and cardiorenal protective properties of SGLT2 inhibitors remain to be explored.

Anti-Inflammatory Properties of the SGLT2 Inhibitor Empagliflozin in Activated Primary Microglia

Sodium-glucose cotransporter 2 (SGLT2) inhibitors, including empagliflozin, are routinely used as antidiabetic drugs. Recent studies indicate that beside its beneficial effects on blood glucose level, empagliflozin may also exert vascular anti-inflammatory and neuroprotective properties. In the brain, microglia are crucial mediators of inflammation, and neuroinflammation plays a key role in neurodegenerative disorders. Dampening microglia-mediated inflammation may slow down disease progression. In this context, we investigated the immunomodulatory effect of empagliflozin on activated primary microglia. As a validated experimental model, rat primary microglial cells were activated into a pro-inflammatory state by stimulation with LPS. The influence of empagliflozin on the expression of pro-inflammatory mediators (NO, Nos2, IL6, TNF, IL1B) and on the anti-inflammatory mediator IL10 was assessed using quantitative PCR and ELISA. Further, we investigated changes in the activation of the ERK1/2 cascade by Western blot and NFkB translocation by immunostaining. We observed that empagliflozin reduces the expression of pro- and anti-inflammatory mediators in LPS-activated primary microglia. These effects might be mediated by NHE-1, rather than by SGLT2, and by the further inhibition of the ERK1/2 and NFkB pathways. Our results support putative anti-inflammatory effects of empagliflozin on microglia and suggest that SGLT2 inhibitors may exert beneficial effects in neurodegenerative disorders.

Cardiovascular protection by SGLT2 inhibitors - Do anti-inflammatory mechanisms play a role?

BACKGROUND

Metabolic syndrome and related metabolic disturbances represent a state of low-grade inflammation, which accelerates insulin resistance, type 2 diabetes (T2D) and cardiovascular disease (CVD) progression. Among antidiabetic medications, sodium glucose co-transporter (SGLT) 2 inhibitors are the only agents which showed remarkable reductions in heart failure (HF) hospitalizations and major cardiovascular endpoints (MACE) as well as renal endpoints regardless of diabetes status in large randomized clinical outcome trials (RCTs). Although the exact mechanisms underlying these benefits are yet to be established, growing evidence suggests that modulating inflammation by SGLT2 inhibitors may play a key role.

SCOPE OF REVIEW

In this manuscript, we summarize the current knowledge on anti-inflammatory effects of SGLT2 inhibitors as one of the mechanisms potentially mediating their cardiovascular (CV) benefits. We introduce the different metabolic and systemic actions mediated by these agents which could mitigate inflammation, and further present the signalling pathways potentially responsible for their proposed direct anti-inflammatory effects. We also discuss controversies surrounding some of these mechanisms.

MAJOR CONCLUSIONS

SGLT2 inhibitors are promising anti-inflammatory agents by acting either indirectly via improving metabolism and reducing stress conditions or via direct modulation of inflammatory signalling pathways. These effects were achieved, to a great extent, in a glucose-independent manner which established their clinical use in HF patients with and without diabetes.

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.

Association between serum insulin levels and heart failure-related parameters in patients with type 2 diabetes and heart failure treated with canagliflozin: a post-hoc analysis of the randomized CANDLE trial

Background

Insulin resistance and hyperinsulinemia in patients with type 2 diabetes (T2D) are adversely associated with the development and worsening of heart failure (HF). Herein, we sought to investigate the effect of canagliflozin on insulin concentrations and the associations of changes in insulin concentrations with HF-related clinical parameters in patients with T2D and HF.

Methods

This was a post-hoc analysis of the investigator-initiated, multicenter, open-label, randomized, controlled CANDLE trial for patients with T2D and chronic HF (UMIN000017669). The endpoints were the effects of 24 weeks of canagliflozin treatment, relative to glimepiride treatment, on insulin concentrations and the relationship between changes in insulin concentrations and clinical parameters of interest, including New York Heart Association (NYHA) classification. The effects of canagliflozin on those parameters were also analyzed by baseline insulin level.

Results

Among the participants in the CANDLE trial, a total of 129 patients (canagliflozin, n = 64; glimepiride, n = 65) who were non-insulin users with available serum insulin data both at baseline and week 24 were included in this analysis. Overall, the mean age was 69.0 ± 9.4 years; 75% were male; the mean HbA1c was 6.8 ± 0.7%; and the mean left ventricular ejection fraction was 59.0 ± 14.1%, with parameters roughly balanced between treatment groups. Canagliflozin treatment significantly reduced insulin concentrations at week 24 (p < 0.001), and the between-group difference (canagliflozin minus glimepiride) in those changes was − 3.52 mU/L (95% confidence interval, − 4.85 to − 2.19; p < 0.001). Decreases in insulin concentrations, irrespective of baseline insulin level, were significantly associated with improvement in NYHA class in patients treated with canagliflozin.

Conclusion

Our findings suggest that canagliflozin treatment in patients with T2D and HF ameliorated excess insulin overload, contributing to the improvement of clinical HF status.

Trial registration: University Medical Information Network Clinical Trial Registry, number 000017669, Registered on May 25, 2015.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01589-3.

SGLT2 Inhibition via Empagliflozin Improves Endothelial Function and Reduces Mitochondrial Oxidative Stress: Insights From Frail Hypertensive and Diabetic Patients

BACKGROUND

Frailty is a multidimensional condition often diagnosed in older adults with hypertension and diabetes, and both these conditions are associated with endothelial dysfunction and oxidative stress. We investigated the functional role of the SGLT2 (sodium glucose cotransporter 2) inhibitor empagliflozin in frail diabetic and hypertensive older adults.

METHODS

We studied the effects of empagliflozin in consecutive hypertensive and diabetic older patients with frailty presenting at the ASL (local health unit of the Italian Ministry of Health) of Avellino, Italy, from March 2021 to January 2022. Moreover, we performed in vitro experiments in human endothelial cells to measure cell viability, permeability, mitochondrial Ca²⁺, and oxidative stress.

RESULTS

We evaluated 407 patients; 325 frail elders with diabetes successfully completed the study. We propensity-score matched 75 patients treated with empagliflozin and 75 with no empagliflozin. We observed a correlation between glycemia and Montreal Cognitive Assessment (MoCA) score and between glycemia and 5-meter gait speed (5mGS). At 3-month follow-up, we detected a significant improvement in the MoCA score and in the 5mGS in patients receiving empagliflozin compared with non-treated subjects. Mechanistically, we demonstrate that empagliflozin significantly reduces mitochondrial Ca²⁺ overload and reactive oxygen species production triggered by high glucose in human endothelial cells, attenuates cellular permeability, and improves cell viability in response to oxidative stress.

CONCLUSIONS

Taken together, our data indicate that empagliflozin reduces frailty in diabetic and hypertensive patients, most likely by decreasing the mitochondrial generation of reactive oxygen species in endothelial cells.

The impact of SGLT2 inhibitors on inflammation: A systematic review and meta-analysis of studies in rodents

BACKGROUND

Inhibition of sodium-glucose cotransporter-2 (SGLT2) has received remarkable attention due to the beneficial effects observed in diabetes mellitus, heart failure, and kidney disease. Several mechanisms have been proposed for these pleiotropic effects, including anti-inflammatory ones. Our systematic review and meta-analysis aimed to assess the effect of SGLT2 inhibition on inflammatory markers in experimental models.

METHODS

A literature search was conducted to detect studies examining the effect of SGLT2 inhibitors on inflammatory markers [interleukin-6 (IL-6), C reactive protein (CRP), tumor necrosis factor-α (TNF-α), and monocyte chemoattractant protein-1 (MCP-1)]. Consequently, a meta-analysis of the included studies was performed, assessing the differences in the levels of the inflammatory markers between the treatment groups as its primary outcome. Moreover, risk of bias, sensitivity analysis and publication bias were evaluated.

RESULTS

The systematic literature review yielded 30 studies whose meta-analysis suggested that treatment with an SGLT2 inhibitor resulted in decreases of IL-6 [standardized mean difference (SMD): -1.56, 95% CI -2.06 to -1.05), CRP (SMD: -2.17, 95% CI -2.80 to -1.53), TNF-α (SMD: -1.75, 95% CI -2.14 to -1.37), and MCP-1 (SMD: -2.04, 95% CI -2.91 to -1.17). The effect on CRP and TNF-α was of lesser magnitude in cases of empagliflozin use. Moderate-to-substantial heterogeneity and possible publication bias were noted. The findings remained largely unaffected after the sensitivity analyses, the exclusion of outlying studies, and trim-and-fill analyses.

CONCLUSION

The present meta-analysis suggests that SGLT2 inhibition results in reduction of inflammatory markers in animal models, further validating the suggested anti-inflammatory mechanism of action.

The Role of Thermogenic Fat Tissue in Energy Consumption

Mammalian adipose tissues are broadly divided into white adipose tissue (WAT) and thermogenic fat tissue (brown adipose tissue and beige adipose tissue). Uncoupling protein 1 (UCP1) is the central protein in thermogenesis, and cells that exhibit induced UCP1 expression and appear scattered throughout WAT are called beige adipocytes, and their induction in WAT is referred to as “beiging”. Beige adipocytes can differentiate from preadipocytes or convert from mature adipocytes. UCP1 was thought to contribute to non-shivering thermogenesis; however, recent studies demonstrated the presence of UCP1-independent thermogenic mechanisms. There is evidence that thermogenic fat tissue contributes to systemic energy expenditure even in human beings. This review discusses the roles that thermogenic fat tissue plays in energy consumption and offers insight into the possibility and challenges associated with its application in the treatment of obesity and type 2 diabetes.

Effectiveness and clinical benefits of new anti-diabetic drugs: A real life experience

We evaluated the clinical impact, in daily clinical practice, of sodium-glucose co-transporter-2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP1RA) therapies in patients with type 2 diabetes. Data from 500 unselected consecutive patients were retrospectively analyzed. Only those with a full assessment at baseline (T0) and after 3 (T3), 6 (T6), and 12 (T12) months of treatment with SGLT2i or GLP1RA were included in the study (n = 167). At baseline, patients had a high mean body weight (BW), abdominal circumference (AC), body mass index (BMI), and HOMA index. Despite normal C-peptide values, 39 patients were being treated with insulin (up to 120 IU/day). During therapy, a progressive improvement in BW, BMI, and AC was observed with both the molecules. Fasting glucose and glycated Hb decrease was already significant at T3 in all patients, while the HOMA index selectively improved with SGLT2i therapy. Renal function parameters remained stable regardless of the drug used. Finally, SGLT2i reduced serum uric acid and improved the lipid profile, while GLP1RA reduced serum levels of liver enzymes. Both the therapeutic regimens allowed a significant reduction or complete suspension of unnecessary insulin therapies. Our real life data confirm the results obtained from randomized clinical trials and should be taken as a warning against inappropriate use of insulin in patients with preserved β-cell function.

Role of Sodium-Glucose Co-Transporter 2 Inhibitors in the Regulation of Inflammatory Processes in Animal Models

Sodium-glucose co-transporter 2 inhibitors, also known as gliflozins, were developed as a novel class of anti-diabetic agents that promote glycosuria through the prevention of glucose reabsorption in the proximal tubule by sodium-glucose co-transporter 2. Beyond the regulation of glucose homeostasis, they resulted as being effective in different clinical trials in patients with heart failure, showing a strong cardio-renal protective effect in diabetic, but also in non-diabetic patients, which highlights the possible existence of other mechanisms through which gliflozins could be exerting their action. So far, different gliflozins have been approved for their therapeutic use in T2DM, heart failure, and diabetic kidney disease in different countries, all of them being diseases that have in common a deregulation of the inflammatory process associated with the pathology, which perpetuates and worsens the disease. This inflammatory deregulation has been observed in many other diseases, which led the scientific community to have a growing interest in the understanding of the biological processes that lead to or control inflammation deregulation in order to be able to identify potential therapeutic targets that could revert this situation and contribute to the amelioration of the disease. In this line, recent studies showed that gliflozins also act as an anti-inflammatory drug, and have been proposed as a useful strategy to treat other diseases linked to inflammation in addition to cardio-renal diseases, such as diabetes, obesity, atherosclerosis, or non-alcoholic fatty liver disease. In this work, we will review recent studies regarding the role of the main sodium-glucose co-transporter 2 inhibitors in the control of inflammation.

Novel Noninvasive Approaches to the Treatment of Obesity: From Pharmacotherapy to Gene Therapy

Recent insights into the pathophysiologic underlying mechanisms of obesity have led to the discovery of several promising drug targets and novel therapeutic strategies to address the global obesity epidemic and its comorbidities. Current pharmacologic options for obesity management are largely limited in number and of modest efficacy/safety profile. Therefore, the need for safe and more efficacious new agents is urgent. Drugs that are currently under investigation modulate targets across a broad range of systems and tissues, including the central nervous system, gastrointestinal hormones, adipose tissue, kidney, liver, and skeletal muscle. Beyond pharmacotherapeutics, other potential antiobesity strategies are being explored, including novel drug delivery systems, vaccines, modulation of the gut microbiome, and gene therapy. The present review summarizes the pathophysiology of energy homeostasis and highlights pathways being explored in the effort to develop novel antiobesity medications and interventions but does not cover devices and bariatric methods. Emerging pharmacologic agents and alternative approaches targeting these pathways and relevant research in both animals and humans are presented in detail. Special emphasis is given to treatment options at the end of the development pipeline and closer to the clinic (ie, compounds that have a higher chance to be added to our therapeutic armamentarium in the near future). Ultimately, advancements in our understanding of the pathophysiology and interindividual variation of obesity may lead to multimodal and personalized approaches to obesity treatment that will result in safe, effective, and sustainable weight loss until the root causes of the problem are identified and addressed.

Metabolic Flexibility and Its Impact on Health Outcomes

A metabolically flexible state exists when there is a rapid switch between glucose and fatty acids during the transition between the fed and fasting state. This flexibility in fuel choice serves to prevent hyperglycemia following a meal and simultaneously ensures an adequate amount of blood glucose is available for delivery to the brain and exclusively glycolytic tissues during fasting. The modern era is characterized by chronic overnutrition in which a mixture of fuels is delivered to the mitochondria in an unabated manner thereby uncoupling the feast and famine situation. The continuous influx of fuel leads to accumulation of reducing equivalents in the mitochondria and an increase in the mitochondrial membrane potential. These changes create a microenvironment fostering the generation of reactive oxygen species and other metabolites leading to deleterious protein modification, cell injury, and ultimately clinical disease. Insulin resistance may also play a primary role in this deleterious effect. The imbalance between mitochondrial energy delivery and use is made worse with a sedentary lifestyle. Maneuvers that restore energy balance across the mitochondria activate pathways that remove or repair damaged molecules and restore the plasticity characteristic of normal energy metabolism. Readily available strategies to maintain energy balance across the mitochondria include exercise, various forms of caloric restriction, administration of sodium-glucose cotransporter-2 inhibitors, cold exposure, and hypobaric hypoxia.

An Overview of the Cardiorenal Protective Mechanisms of SGLT2 Inhibitors

Sodium-glucose co-transporter 2 (SGLT2) inhibitors block glucose reabsorption in the renal proximal tubule, an insulin-independent mechanism that plays a critical role in glycemic regulation in diabetes. In addition to their glucose-lowering effects, SGLT2 inhibitors prevent both renal damage and the onset of chronic kidney disease and cardiovascular events, in particular heart failure with both reduced and preserved ejection fraction. These unexpected benefits prompted changes in treatment guidelines and scientific interest in the underlying mechanisms. Aside from the target effects of SGLT2 inhibition, a wide spectrum of beneficial actions is described for the kidney and the heart, even though the cardiac tissue does not express SGLT2 channels. Correction of cardiorenal risk factors, metabolic adjustments ameliorating myocardial substrate utilization, and optimization of ventricular loading conditions through effects on diuresis, natriuresis, and vascular function appear to be the main underlying mechanisms for the observed cardiorenal protection. Additional clinical advantages associated with using SGLT2 inhibitors are antifibrotic effects due to correction of inflammation and oxidative stress, modulation of mitochondrial function, and autophagy. Much research is required to understand the numerous and complex pathways involved in SGLT2 inhibition. This review summarizes the current known mechanisms of SGLT2-mediated cardiorenal protection.

Emerging Roles of Sodium Glucose Cotransporter 2 (SGLT-2) Inhibitors in Diabetic Cardiovascular Diseases: Focusing on Immunity, Inflammation and Metabolism

Diabetes mellitus (DM) is one of the most fast evolving global issues characterized by hyperglycemia. Patients with diabetes are considered to face with higher risks of adverse cardiovascular events. Those are the main cause of mortality and disability in diabetes patients. There are novel antidiabetic agents that selectively suppress sodium-glucose cotransporter-2 (SGLT-2). They work by reducing proximal tubule glucose reabsorption. Although increasing evidence has shown that SGLT-2 inhibitors can contribute to a series of cardiovascular benefits in diabetic patients, including a reduced incidence of major adverse cardiovascular events and protection of extracardiac organs, the potential mechanisms of SGLT2 inhibitors’ cardiovascular protective effects are still not fully elucidated. Given the important role of inflammation and metabolism in diabetic cardiovascular diseases, this review is intended to rationally compile the multifactorial mechanisms of SGLT-2 inhibitors from the point of immunity, inflammation and metabolism, depicting the fundamental cellular and molecular processing of SGLT-2 inhibitors exerting regulating immunity, inflammation and metabolism. Finally, future directions and perspectives to prevent or delay cardiovascular complications in DM by SGLT-2 inhibitors are presented.

Neohesperidin Dihydrochalcone and Neohesperidin Dihydrochalcone-O-Glycoside Attenuate Subcutaneous Fat and Lipid Accumulation by Regulating PI3K/AKT/mTOR Pathway In Vivo and In Vitro

Neohesperidin dihydrochalcone (NHDC), a semi-natural compound from bitter orange, is an intense sweetener. The anti-obesity effects of NHDC and its glycosidic compound, NHDC-O-glycoside (GNHDC), were investigated. C57BLKS/J db/db mice were supplemented with NHDC or GNHDC (100 mg/kg b.w.) for 4 weeks. Body weight gain, subcutaneous tissues, and total adipose tissues (sum of perirenal, visceral, epididymal, and subcutaneous adipose tissue) were decreased in the NHDC and GNHDC groups. Fatty acid uptake, lipogenesis, and adipogenesis-related genes were decreased, whereas β-oxidation and fat browning-related genes were up-regulated in the sweetener groups. Furthermore, both sweeteners suppressed the level of triacylglycerol accumulation, lipogenesis, adipogenesis, and proinflammatory cytokines in the 3T3-L1 cells. The PI3K/AKT/mTOR pathway was also down-regulated, and AMP-acttvated protein kinase (AMPK) was phosphorylated in the treatment groups. These results suggest that NHDC and GNHDC inhibited subcutaneous fat and lipid accumulation by regulating the PI3K/AKT/mTOR pathway and AMPK-related lipogenesis and fat browning.

Can sodium-glucose co-transporter-2 (SGLT-2) inhibitor reduce the risk of adverse complications due to COVID-19? - Targeting hyperinflammation

Sodium-glucose co-transporter-2 (SGLT-2) inhibitors are antidiabetic drugs with numerous pleiotropic and positive clinical effects, particularly regarding a reno-cardiovascular protective effect. More recent studies, including from our laboratory, have highlighted some novel anti-inflammatory activity of SGLT-2 inhibitors. This may confer a theoretical advantage in mitigating excessive cytokine production and inflammatory response associated with serious COVID-19 infection. Specifically, earlier research has demonstrated that SGLT-2 inhibitors are associated with a notable decrease in inflammatory indicators, for example, C-reactive protein, ferritin, and interleukin-6. Furthermore, SGLT-2 inhibitors exhibit a favourable impact on the vascular endothelium function; this could pertinence the prophylaxis of the thrombotic issues that arise in SARS-CoV-2. This review provides an overview of the COVID-19 indirect immune response mechanisms impacting the cardiovascular system and the possible effect of SGLT-2 inhibitors on the management of COVID-19.

The Treatment With the SGLT2 Inhibitor Empagliflozin Modifies the Hepatic Metabolome of Male Zucker Diabetic Fatty Rats Towards a Protective Profile

The EMPA-REG OUTCOME (Empagliflozin, Cardiovascular Outcome Event Trial in patients with Type 2 Diabetes Mellitus (T2DM)) trial evidenced the potential of sodium-glucose cotransporter 2 (SGLT2) inhibitors for the treatment of patients with diabetes and cardiovascular disease. Recent evidences have shown the benefits of the SGLT2 inhibitor empagliflozin on improving liver steatosis and fibrosis in patients with T2DM. Metabolomic studies have been shown to be very useful to improve the understanding of liver pathophysiology during the development and progression of metabolic hepatic diseases, and because the effects of empagliflozin and of other SGLT2 inhibitors on the complete metabolic profile of the liver has never been analysed before, we decided to study the impact on the liver of male Zucker diabetic fatty (ZDF) rats of a treatment for 6 weeks with empagliflozin using an untargeted metabolomics approach, with the purpose to help to clarify the benefits of the use of empagliflozin at hepatic level. We found that empagliflozin is able to change the hepatic lipidome towards a protective profile, through an increase of monounsaturated and polyunsaturated glycerides, phosphatidylcholines, phosphatidylethanolamines, lysophosphatidylinositols and lysophosphatidylcholines. Empagliflozin also induces a decrease in the levels of the markers of inflammation IL-6, chemerin and chemerin receptor in the liver. Our results provide new evidences regarding the molecular pathways through which empagliflozin could exert hepatoprotector beneficial effects in T2DM.

Mulberry (Morus alba L.) leaf polysaccharide ameliorates insulin resistance- and adipose deposition-associated gut microbiota and lipid metabolites in high-fat diet-induced obese mice

Dietary supplements are currently being used to ameliorate metabolic alterations via maintaining gut microflora balance. Mulberry leaf is known as medicine homologous food for its glucose- and lipid-modulating properties. However, the effects of mulberry leaf polysaccharide (MP) on metabolic dysbiosis and gut microbiota are still poorly understood. After extraction and characterization, the beneficial effects of water-soluble MP were evaluated in high-fat diet-induced obese mice. MP treatment could reduce adipose tissue, improve insulin resistance, and alleviate the pathological lesions in colon. Investigation of the underlying mechanism showed that MP modulated gut microbial community by 16S rRNA analysis and reversed the elevation of lipid indexes by plasma lipidomics analysis. Correlation analysis indicated that the abundance of seven key bacterial species and six lipids were closely associated with the metabolic traits, respectively. Overall, MP could ameliorate metabolic disorders, and modify the gut microbiota and lipids. This would greatly facilitate the utilization of MP as a functional food.

Novel Antidiabetic Strategies and Diabetologists' Views in Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease worldwide with high prevalence, especially in individuals with obesity and type 2 diabetes. Among individuals with type 2 diabetes, the severe insulin resistant subgroup has the greatest risk of NAFLD, likely due to dysfunctional adipose tissue mass but also genetic factors, and may progress earlier to inflammatory and profibrotic nonalcoholic steatohepatitis (NASH). NASH has been associated with increased liver-related as well as cardiovascular morbidity and mortality. International diabetes associations recommend certain screening and treatment strategies for NASH in type 2 diabetes, which, however, bear several limitations such as lack of accurate noninvasive diagnostic tools and targeted treatments. Currently, antihyperglycemic drug concepts based on glucagon-like peptide-1 receptor agonists and sodium glucose cotransporter 2 inhibitors offer metabolic as well as cardiorenal benefits and provide treatment options for both hyperglycemia and NASH in type 2 diabetes.

Efficacy and Safety of Empagliflozin on Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis

OBJECTIVE

Clinical trials have recently shown a connection between nonalcoholic fatty liver disease (NAFLD) and empagliflozin. This paper aimed at comprehensively assessing the effectiveness and security of empagliflozin in NAFLD patients.

METHODS

PubMed, Embase, Web of Science, Cochrane Library, CNKI, CBM, Wan-Fang digital database, VIP, and WHO ICTRP were searched for randomized controlled trials (RCTs) on the role of empagliflozin in NAFLD from inception to November 2, 2021. For continuous dating, we used values of mean differences (MD) to present.

RESULTS

A total of four articles involving 244 NAFLD patients were included. Compared with the control group, empagliflozin could significantly reduce the body mass index (BMI) (MD: -0.98 [95% CI: -1.87, -0.10], p = 0.03), liver stiffness measurement (LSM) (MD: 0.49 [95% CI: -0.93, -0.06], p = 0.03), aspartate aminotransferase (AST) (MD: -3.10 [95% CI: -6.18, -0.02], p = 0.05), homeostasis model assessment of insulin resistance (HOMA-IR) (MD: -0.45 [95% CI: -0.90, 0.00], p = 0.05) of the treatment group.

CONCLUSIONS

Empagliflozin can improve body composition, insulin resistance, and liver fibrosis and decrease the hepatic enzymes in patients with NAFLD. Empagliflozin emerges as a new option for treating patients with NAFLD. However, further research shall determine the efficacy and safety of empagliflozin in NAFLD.

Exosome miR-155-5p Derived from Lung Cancer Hcc827 Promotes Macrophage Activation and Lung Cancer Progression

This stud intends to assess whether exosome miR-155-5p derived from human non-small cell lung cancer cells (Hcc827) activates macrophages in lung cancer. Lung cancer Hcc827 cells were assigned into control group and expeirmental group (cultured with macrophages, THP-1 activated by exosome miR-155-5P derived from Hcc827) followed by analysis of macrophage markers inducible nitric oxide synthase (INOS), recombinant human CD163 (CD163), matrix metallopeptidase 9 (MMP9), matrix metallopeptidase 2 (MMP2), and E-cadherin by real-time fluorescent quantitative PCR (RFQ-PCR), IL-10, IL-6 and IL-8 levels by chemiluminescence, cell invasion by Transwell assay and related protein expression by Western blot. miR-155-5p treatment significantly reduced INOS and TNF-β expressions and increased CD163, TNF-α, IL-8, IL-6 and IL-10 expressions along with enhanced cell invasion. In addition, MMP9 and MMP2 expressions in experimental group were significantly increased and E-cdherin was reduced. In conclusion, exosome miR-155-5p derived from lung cancer Hcc827 cells activates macrophages and enhanced lung cancer cell invasion.

Neuroprotective Effect of SGLT2 Inhibitors

Patients with diabetes are at higher risk of cardiovascular diseases and cognitive impairment. SGLT2 inhibitors (Empagliflozin, Canagliflozin, Dapagliflozin, Ertugliflozin, Sotagliflozin) are newer hypoglycemic agents with many pleiotropic effects. In this review, we discuss their neuroprotective potential. SGLT2 inhibitors (SGLT2i) are lipid-soluble and reach the brain/serum ratio from 0.3 to 0.5. SGLT receptors are present in the central nervous system (CNS). Flozins are not fully SGLT2-selective and have an affinity for the SGLT1 receptor, which is associated with protection against ischemia/reperfusion brain damage. SGLT2i show an anti-inflammatory and anti-atherosclerotic effect, including reduction of proinflammatory cytokines, M2 macrophage polarization, JAK2/STAT1 and NLRP3 inflammasome inhibition, as well as cIMT regression. They also mitigate oxidative stress. SGLT2i improve endothelial function, prevent remodeling and exert a protective effect on the neurovascular unit, blood-brain barrier, pericytes, astrocytes, microglia, and oligodendrocytes. Flozins are also able to inhibit AChE, which contributes to cognitive improvement. Empagliflozin significantly increases the level of cerebral BDNF, which modulates neurotransmission and ensures growth, survival, and plasticity of neurons. Moreover, they may be able to restore the circadian rhythm of mTOR activation, which is quite a novel finding in the field of research on metabolic diseases and cognitive impairment. SGLT2i have a great potential to protect against atherosclerosis and cognitive impairment in patients with type 2 diabetes mellitus.

Empagliflozin Induces White Adipocyte Browning and Modulates Mitochondrial Dynamics in KK Cg-Ay/J Mice and Mouse Adipocytes

Background: White adipose tissue (WAT) browning is a promising target for obesity prevention and treatment. Empagliflozin has emerged as an agent with weight-loss potential in clinical and in vivo studies, but the mechanisms underlying its effect are not fully understood. Here, we investigated whether empagliflozin could induce WAT browning and mitochondrial alterations in KK Cg-Ay/J (KKAy) mice, and explored the mechanisms of its effects.

Methods: Eight-week-old male KKAy mice were administered empagliflozin or saline for 8 weeks and compared with control C57BL/6J mice. Mature 3T3-L1 adipocytes were treated in the presence or absence of empagliflozin. Mitochondrial biosynthesis, dynamics, and function were evaluated by gene expression analyses, fluorescence microscopy, and enzymatic assays. The roles of adenosine monophosphate–activated protein kinase (AMPK) and peroxisome proliferator–activated receptor-γ coactivator-1-alpha (PGC-1α) were determined through AICAR (5-Aminoimidazole-4-carboxamide1-β-D-ribofuranoside)/Compound C and RNA interference, respectively.

Results: Empagliflozin substantially reduced the bodyweight of KKAy mice. Mice treated with empagliflozin exhibited elevated cold-induced thermogenesis and higher expression levels of uncoupling protein 1 (UCP1) and other brown adipose tissue signature proteins in epididymal and perirenal WAT, which was an indication of browning in these WAT depots. At the same time, empagliflozin enhanced fusion protein mitofusin 2 (MFN2) expression, while decreasing the levels of the fission marker phosphorylated dynamin-related protein 1 (Ser616) [p-DRP1 (Ser616)] in epididymal and perirenal WAT. Empagliflozin also increased mitochondrial biogenesis and fusion, improved mitochondrial integrity and function, and promoted browning of 3T3-L1 adipocytes. Further, we found that AMPK signaling activity played an indispensable role in empagliflozin-induced browning and mitochondrial biogenesis, and that PGC-1α was required for empagliflozin-induced fusion. Whether empagliflozin activates AMPK by inhibition of SGLT2 or by independent mechanisms remains to be tested.

Conclusion: Our results suggest that empagliflozin is a promising anti-obesity treatment, which can immediately induce WAT browning mitochondrial biogenesis, and regulate mitochondrial dynamics.

Inflammation and Oxidative Stress in Diabetic Kidney Disease: The Targets for SGLT2 Inhibitors and GLP-1 Receptor Agonists

The incidence of type 2 diabetes (T2D) has been increasing worldwide, and diabetic kidney disease (DKD) remains one of the leading long-term complications of T2D. Several lines of evidence indicate that glucose-lowering agents prevent the onset and progression of DKD in its early stages but are of limited efficacy in later stages of DKD. However, sodium-glucose cotransporter-2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor (GLP-1R) agonists were shown to exert nephroprotective effects in patients with established DKD, i.e., those who had a reduced glomerular filtration rate. These effects cannot be solely attributed to the improved metabolic control of diabetes. In our review, we attempted to discuss the interactions of both groups of agents with inflammation and oxidative stress—the key pathways contributing to organ damage in the course of diabetes. SGLT2i and GLP-1R agonists attenuate inflammation and oxidative stress in experimental in vitro and in vivo models of DKD in several ways. In addition, we have described experiments showing the same protective mechanisms as found in DKD in non-diabetic kidney injury models as well as in some tissues and organs other than the kidney. The interaction between both drug groups, inflammation and oxidative stress appears to have a universal mechanism of organ protection in diabetes and other diseases.