Swertisin, a novel SGLT2 inhibitor, with improved glucose homeostasis for effective diabetes therapy.

Failing pancreas and subsequent loss of pancreatic ß cells worsen diabetic conditions which are further alleviated by the mounting up of glucose levels. Inhibition of sodium glucose cotransporter 2 (SGLT2) in the kidney responsible for glucose reabsorption strikingly reduces blood glucose levels. Bioactive swertisin showed a promising glucose-lowering effect. Hence, we aimed to mechanistically dissect the glucose lowering property of swertisin. A systematic in silico, in vitro, and in vivo approach was directed for target analysis of swertisin. Molecular docking was performed with Swertisn-hSGLT2 complex. Glucose uptake assay and protein expression for SGLT2 and regulatory proteins were performed under swertisin effect. Various physiological and metabolic parameters were evaluated in STZ induced BALB/c mice using swertisin treatment. SGLT2 expression was evaluated in the kidney tissue of mice. Swertisn-hSGLT2 molecularly docked complex showed similar binding energy compared to the Canagliflozin-hSGLT2 complex. Swertisin inhibited glucose uptake and decreased expression of SGLT2 in HEK293 cells. Swertisin does not affect GLUT mediated glucose transport. Swertisin treated diabetic mice demonstrated remarkable improvement in overall glucose homeostasis. Reduced expression of SGLT2 was found in kidney tissue along with reduced PKC expression which is one of the key regulators of SGLT2. Our study explored SGLT2 as a selective target of swertisin for its swift glucose-lowering action which not only inhibits SGLT2 but also reduces its expression in diabetic condition. Thus, the potential property of swertisin as a glucose-lowering agent is remarkable which points towards the likelihood of a wider avenue of diabetes therapy.

Evaluation of Serum Vitamin D Levels in Patients with Systemic Sclerosis and Healthy Controls: Results of a Pilot Study.

BACKGROUND: The anti-inflammatory, immunomodulatory, and anti-proliferative effects of vitamin D in pathogenesis of autoimmune diseases have been highlighted in recent years but implications of vitamin D deficiency in systemic sclerosis (SSc) remain understudied. OBJECTIVES: To evaluate serum vitamin D levels in SSc patients and matched controls. MATERIALS AND METHODS: Serum vitamin D levels were estimated in 38 (M:F 5:33) patients aged 23-70 years of untreated SSc and age and gender matched healthy controls. Clinical and investigative evaluation for skin sclerosis by modified Rodnan skin score (mRSS), presence of digital ulcers, Raynaud's phenomenon, type of auto-antibodies, systemic involvement, and serum vitamin D levels were performed. Serum vitamin D levels were defined as normal (30-100 ng/ml), insufficient (10-30 ng/ml), and deficient (<10 ng/ml). RESULTS: Serum vitamin D levels (median ± IQR) were 19.5 ± 77.8 ng/ml in 38 patients and 100 ± 31.3 ng/ml in controls each. Vitamin D deficiency in 13 (34.2%) and insufficiency in 10 (26.3%) patients were identified. Only 2 (5.3%) controls had vitamin D insufficiency and the difference was statistically significant (P = 0.001). An inverse relationship was observed between mRSS and serum vitamin D levels. CONCLUSIONS: Patients with SSc have significantly lower serum vitamin D levels than healthy controls. Serum vitamin D levels do not correlate well with age, gender, disease duration or its variants, type of auto antibodies, presence of digital ulceration, or systemic involvement but has inverse correlation with skin sclerosis. Better-designed studies will perhaps resolve issues of potential benefits of vitamin D supplementation in modification of disease activity or severity in SSc.

Dexamethasone Alters the Appetite Regulation via Induction of Hypothalamic Insulin Resistance in Rat Brain.

Elevated levels of glucocorticoid, a steroid hormone released in response to stress, have been implicated in the pathophysiology of diabetes, which is now known to extend its effect on brain functions. Hence, we aimed to investigate the status of brain insulin signaling in response to dexamethasone (a synthetic glucocorticoid) treatment in female Charles Foster rat. This model exhibited pronounced hyperinsulinemia and glucose intolerance with loss in appetite and body weight. Immunoblotting of insulin receptor (INSR)-PI3kinase-AKT demonstrated reduced insulin signaling in hypothalamus but no change in hippocampus, cortex, and cerebellum in dexamethasone-treated rats as compared to vehicle-treated rats, signifying the diversity of distribution and function of insulin in different brain regions. These results also correlated with appetite change, a key function governed by hypothalamus. Hence, we further explored the hypothalamic feeding circuit and found altered levels of neuropeptide genes (Agrp, Npy, Pomc) and candidate nutrient sensors (GLUT1, SirT1, and PPARγ). There was also a considerable reduction in glycogen content and appetite-regulating neurotransmitters (GABA, glutamate, dopamine) in dexamethasone-treated rats. Thus, concluding that dexamethasone not only induces peripheral insulin resistance but also impairs hypothalamic function of appetite regulation via the interwoven cascade of insulin signaling, neurotransmitters, and neuropeptides. Graphical Abstract Reduced insulin signaling as well as elevated glucocorticoid levels in hypothalamus modulates the key appetite regulating neuropeptides, neurotransmitters, and nutrient sensors resulting into reduced appetite and bodyweight.

Anti-apoptotic and cytoprotective effect of Enicostemma littorale against oxidative stress in Islets of Langerhans.

Context Oxidative stress induces apoptosis within Islets of Langerhans in diabetes mellitus (DM). Enicostemma littorale blume, herb of the Gentianaceae family is used as an anti-diabetic agent across rural India. Objective This report demonstrates potent anti-apoptotic and cyto-protective activity of Enicostemma littorale MeOH extract (EL MeOH ext.) against 50 µM H2O2 in isolated rat Islets. Materials and methods In this study, the whole plant methanolic extract of EL with doses 0.25-4 mg/mL each for the preincubation duration of 0.5-4 h against 50 µM H2O2 were tested for optimum protective dose and time by Trypan blue dye exclusion assay. Islet intracellular reactive oxygen species (ROS) was quantified by DCFDA staining and cell death using PS/PI & FDA/PI staining. Further, comet assay, biochemical assessment of caspase-3 and antioxidant enzyme activities along with immunoblotting of PARP-1, caspase-3, TNF-α activation and p-P38 MapK (stress kinase) induction was performed. Results The optimized dose of EL MeOH ext. 2 mg/mL for 2 h was used throughout the study, which significantly decreased total Intracellular ROS and cell death. Further, caspase-3 activity, PARP-1 cleavage, p-P38 MapK (stress kinase) activation and TNF-α levels, which had been significantly elevated, were normalized. Antioxidant enzymes like catalase, superoxide dismutase, reduced glutathione and glutathione peroxidase, along with Comet assay, demonstrated that pretreatment with EL MeOH ext. can augment antioxidant enzyme activities and protect from DNA damage. Discussion and conclusions Significant anti-apoptotic and cyto-protective effects were mediated by EL with Islets of Langerhans subjected to oxidative stress-induced cell death.

Swertiamarin: An Active Lead from Enicostemma littorale Regulates Hepatic and Adipose Tissue Gene Expression by Targeting PPAR- γ and Improves Insulin Sensitivity in Experimental NIDDM Rat Model.

Enicostemma littorale (EL) Blume is one of the herbs widely used for treating and alleviating the effects of both type I and type II diabetes. However, lack of understanding of mechanism precludes the use of the herb and its molecules. In this study, we attempt to unravel the molecular mechanism of action of swertiamarin, a compound isolated form EL, by comparing its molecular effects with those of aqueous EL extract in alleviating the insulin resistance in type II diabetes. We further investigated hypolipidemic and insulin sensitizing effect of swertiamarin in experimentally induced noninsulin dependent diabetes mellitus (NIDDM) in rats. Swertiamarin (50 mg/kg) and aqueous extract (15 grams dried plant equivalent extract/kg) were administered to rats orally for 40 days and tight regulation of serum glucose, insulin, and lipid profile was found in both groups. Their mode of action was by restoring G6Pase and HMG-CoA reductase activities to normal levels and restoring normal transcriptional levels of PEPCK, GK, Glut 2, PPAR- γ , leptin, adiponectin, LPL, SREBP-1c, and Glut 4 genes. This suggests that both treatments increased insulin sensitivity and regulated carbohydrate and fat metabolism. This is the first report on the role of SM in regulating the PPAR γ -mediated regulation of candidate genes involved in metabolism in peripheral tissues in vivo.

A Small Molecule Swertisin from Enicostemma littorale Differentiates NIH3T3 Cells into Islet-Like Clusters and Restores Normoglycemia upon Transplantation in Diabetic Balb/c Mice.

Aim. Stem cell therapy is one of the upcoming therapies for the treatment of diabetes. Discovery of potent differentiating agents is a prerequisite for increasing islet mass. The present study is an attempt to screen the potential of novel small biomolecules for their differentiating property into pancreatic islet cells using NIH3T3, as representative of extra pancreatic stem cells/progenitors. Methods. To identify new agents that stimulate islet differentiation, we screened various compounds isolated from Enicostemma littorale using NIH3T3 cells and morphological changes were observed. Characterization was performed by semiquantitative RT-PCR, Q-PCR, immunocytochemistry, immunoblotting, and insulin secretion assay for functional response in newly generated islet-like cell clusters (ILCC). Reversal of hyperglycemia was monitored after transplanting ILCC in STZ-induced diabetic mice. Results. Among various compounds tested, swertisin, an isolated flavonoid, was the most effective in differentiating NIH3T3 into endocrine cells. Swertisin efficiently changed the morphology of NIH3T3 cells from fibroblastic to round aggregate cell cluster in huge numbers. Dithizone (DTZ) stain primarily confirmed differentiation and gene expression studies signified rapid onset of differentiation signaling cascade in swertisin-induced ILCC. Molecular imaging and immunoblotting further confirmed presence of islet specific proteins. Moreover, glucose induced insulin release (in vitro) and decreased fasting blood glucose (FBG) (in vivo) in transplanted diabetic BALB/c mice depicted functional maturity of ILCC. Insulin and glucagon expression in excised islet grafts illustrated survival and functional integrity. Conclusions. Rapid induction for islet differentiation by swertisin, a novel herbal biomolecule, provides low cost and readily available differentiating agent that can be translated as a therapeutic tool for effective treatment in diabetes.

Association of cadmium and lead with antioxidant status and incidence of benign prostatic hyperplasia in patients of Western India.

The association of cadmium (Cd) and lead (Pb) in the pathophysiology and progression of benign prostate hyperplasia (BPH) has been evaluated in an epidemiological study with 116 BPH patients of the western part of India. The prostatic acid phosphatase activity, prostate-specific antigen, maximum urinary flow rate (Q max), and redox status of BPH patients were correlated with Cd and Pb contents. Additionally, patients were also separated on the basis of their age, genetic lineage, and additive habits and correlated with the Cd, Pb, and Q max levels. Our results suggest that the accumulation of toxic metals in prostate tissue has a significant positive correlation with the pathogenesis of BPH. Cd and Pb exert their effects through altered antioxidant defense mechanisms, ultimately leading to increased BPH severity. Progression of the pathogenesis also depends on other factors such as additive habits, genetic lineage, and age of the patients.

Cardioprotective and antihypertensive effects of Enicostemma littorale Blume extract in fructose-fed rats.

We investigated the protective effects of Enicostemma littorale Blume (EL) extract on hypertension and insulin resistance along with its associated cardiovascular complications in high fructose (HF) fed rats. For this, rats were divided among 4 groups: (i) control, fed laboratory chow; (ii) fed with a high level of fructose; (iii) fed with a high level of fructose plus E. littorale extract; and (iv) fed with a high level of fructose plus rosiglitazone (Rg). EL and Rg treatments were given simultaneously with HF diet. The results show that untreated HF-fed rats showed altered oral glucose tolerance, increased fasting insulin, and increased fasting glucose. These rats also exhibited hypertriglyceridemia, moderate hypertension, platelet hyperaggregability, decreased prothrombin time, activated partial thromboplastin time, altered vascular reactivity, and increased serum levels of enzymes (creatine kinase, type muscle-brain (CK-MB), aspartate aminotransferase (SGOT), lactate dehydrogenase (LDH), and alanine aminotransferase (SGPT). This is the first demonstration of platelet hyperaggregation and prothrombotic alteration in HF-fed rats. HF-fed rats treated with EL showed improved insulin resistance, along with reduced hypertriglyceridemia, hypertension, platelet aggregability, blood coagulation, serum enzymes (CK-MB, SGOT, LDH and SGPT), and vascular reactivity. These effects of EL in HF-induced hypertensive rats might be associated with the suppression of hyperinsulinemia and hypertriglyceridemia, along with its antiatherogenic and antithrombogenic potential. These data indicate that the aqueous extract of EL has great therapeutic potential for the prevention and (or) management of insulin resistance and the associated hypertension.

Hypolipidaemic and antioxidant effect of Enicostemma littorale Blume aqueous extract in cholesterol fed rats.

Enicostemma littorale aqueous extract (1.5 g/100 g body weight/day, p.o.) was administered to rats along with hypercholesterolaemic diet for 6 weeks and the hypolipidaemic and antioxidant effect was evaluated. Feeding cholesterol increased serum cholesterol, serum triglycerides, LDL, VLDL and decreased HDL levels as compared to normal diet fed rats. Enicostemma littorale treatment increased HDL levels and decreased serum cholesterol, triglyceride, LDL, VLDL, LDL/HDL ratio. In addition, treatment with the extract showed a decrease in activities of erythrocyte catalase, superoxide dismutase and lipid peroxidation levels, with an increase in reduced glutathione levels as compared to cholesterol fed untreated rats. Liver and kidney cholesterol levels and triglyceride levels were also decreased in Enicostemma littorale treated rats. Hepatic HMG CoA reductase activity was significantly reduced in the extract treated hypercholesterolemic rats. Lovastatin was used as a reference drug. The hypolipidaemic and antioxidant effect of Enicostemma littorale aqueous extract in cholesterol fed rats is being reported for the first time.

Glucose lowering effect of aqueous extract of Enicostemma littorale Blume in diabetes: a possible mechanism of action.

Diabetes mellitus is a chronic metabolic disorder characterized by hyperglycemia. Enicostemma littorale Blume is a small herb and recently we have reported its blood glucose lowering potential in alloxan induced diabetic rats. A single dose of aqueous extract of E. littorale (15 g dry plant equivalent extract per kg) had shown significant increase in the serum insulin levels in alloxan-induced diabetic rats at 8 h. The insulinotropic action of aqueous extract of E. littorale was further investigated using rat pancreatic islets. Extract has the potential to enhance glucose-induced insulin release at 11.1 mM glucose from isolated rat pancreatic islets and was partially able to reverse the effect of diazoxide (0.25 mM). Incubation with Ca(2+) chelator (EGTA) and Ca(2+) channel blocker (nimodipine) did not affect the glucose-induced insulin release augmented by the extract. Above results suggest the glucose lowering effect of aqueous extract of E. littorale to be associated with potentiation of glucose-induced insulin release through K(+)-ATP channel dependent pathway but did not require Ca(2+) influx.