Reciprocal Regulation of Hepatic TGF-ß1 and Foxo1 Controls Gluconeogenesis and Energy Expenditure.

Obesity and insulin resistance are risk factors for the pathogenesis of type 2 diabetes (T2D). Here, we report that hepatic TGF-ß1 expression positively correlates with obesity and insulin resistance in mice and humans. Hepatic TGF-ß1 deficiency decreased blood glucose levels in lean mice and improved glucose and energy dysregulations in diet-induced obese (DIO) mice and diabetic mice. Conversely, overexpression of TGF-ß1 in the liver exacerbated metabolic dysfunctions in DIO mice. Mechanistically, hepatic TGF-ß1 and Foxo1 are reciprocally regulated: fasting or insulin resistance caused Foxo1 activation, increasing TGF-ß1 expression, which, in turn, activated protein kinase A, stimulating Foxo1-S273 phosphorylation to promote Foxo1-mediated gluconeogenesis. Disruption of TGF-ß1→Foxo1→TGF-ß1 looping by deleting TGF-ß1 receptor II in the liver or by blocking Foxo1-S273 phosphorylation ameliorated hyperglycemia and improved energy metabolism in adipose tissues. Taken together, our studies reveal that hepatic TGF-ß1→Foxo1→TGF-ß1 looping could be a potential therapeutic target for prevention and treatment of obesity and T2D. ARTICLE HIGHLIGHTS: Hepatic TGF-ß1 levels are increased in obese humans and mice. Hepatic TGF-ß1 maintains glucose homeostasis in lean mice and causes glucose and energy dysregulations in obese and diabetic mice. Hepatic TGF-ß1 exerts an autocrine effect to promote hepatic gluconeogenesis via cAMP-dependent protein kinase-mediated Foxo1 phosphorylation at serine 273, endocrine effects on brown adipose tissue action, and inguinal white adipose tissue browning (beige fat), causing energy imbalance in obese and insulin-resistant mice. TGF-ß1→Foxo1→TGF-ß1 looping in hepatocytes plays a critical role in controlling glucose and energy metabolism in health and disease.

Systematic assessment of streptozotocin-induced diabetic metabolic alterations in rats using metabolomics.

Purpose: Type 1 diabetes is characterized by elevated blood glucose levels, which negatively impacts multiple organs and tissues throughout the body, and its prevalence is on the rise. Prior reports primarily investigated the serum and urine specimen from diabetic patients. However, only a few studies examined the overall metabolic profile of diabetic animals or patients. The current systemic investigation will benefit the knowledge of STZ-based type 1 diabetes pathogenesis. Methods: Male SD rats were arbitrarily separated into control and streptozotocin (STZ)-treated diabetic rats (n = 7). The experimental rats received 50mg/kg STZ intraperitoneal injection daily for 2 consecutive days. Following 6 weeks, metabolites were assessed via gas chromatography-mass spectrometry (GC-MS), and multivariate analysis was employed to screen for differentially expressed (DE) metabolites between the induced diabetic and normal rats. Results: We identified 18, 30, 6, 24, 34, 27, 27 and 12 DE metabolites in the serum, heart, liver, kidney, cortex, renal lipid, hippocampus, and brown fat tissues of STZ-treated diabetic rats, compared to control rats. Based on our analysis, the largest differences were observed in the amino acids (AAs), B-group vitamin, and purine profiles. Using the metabolic pathway analysis, we screened 13 metabolic pathways related to the STZ-exposed diabetes pathogenesis. These pathways were primarily AA metabolism, followed by organic acids, sugars, and lipid metabolism. Conclusion: Based on our GC-MS analysis, we identified potential metabolic alterations within the STZ-exposed diabetic rats, which may aid in the understanding of diabetes pathogenesis.

Biosynthesis of gold nanoparticles using leaf extract of Dittrichia viscosa and in vivo assessment of its anti-diabetic efficacy.

Several studies have reported the anti-diabetic effect of biologically synthesized gold nanoparticles (AuNPs). This study was designed to investigate the in vivo anti-diabetic activity of AuNPs synthesized using the leaf extract of Dittrichia viscosa in a high-fat diet (HFD)/streptozotocin (STZ)-induced diabetes in rats. AuNPs were synthesized using the leaf extract of D. viscosa, and the synthesized AuNPs were characterized by UV-visible spectrophotometer, dynamic light scattering (DLS), zeta potential, and transmission electron microscopy (TEM). To study the anti-hyperglycemic effect of the AuNPs formed using D. viscosa extract, adult male Sprague-Dawley rats were divided into three groups (6-8 rats/group) as follows: control group, a diabetic group without treatment, and a diabetic group treated intraperitoneally with a daily injection of AuNPs at a dose of 2.5 mg/kg for 21 days. Diabetes was induced by maintaining the rats on HFD for 2 weeks, followed by a single intraperitoneal injection of 45 mg/kg of STZ. Serum and liver samples were collected at the end of the treatment period and used to measure glucose levels and hepatic gene expression and activity of phosphoenolpyruvate carboxykinase (PEPCK), the rate-limiting enzyme in the liver gluconeogenic pathway. The AuNPs formed using D. viscosa extract were mainly spherical with a size range between 20 and 50 nm with good stability and dispersity, as indicated by the zeta potential and DLS measurements. Treatment with AuNP significantly lowered the blood glucose level, the gene expression, and the activity of hepatic PEPCK in comparison to the diabetic untreated group (P < 0.05). This study suggests that AuNPs synthesized using D. viscosa leaf extract can alleviate hyperglycemia in HFD/STZ-induced diabetes in rats, which could be through the reduction of hepatic gluconeogenesis by inhibiting the expression and activity of the hepatic PEPCK gene. Schematic illustration of the biosynthesis of AuNPs showing their distinctive morphology under the EM. The generated particles were injected into animals and serum glucose levels were reported in addition to the PEPCK expression and activity.

In vitro assessment of the DNA damage and senility of CD117+ stem cells collected from diabetic mice.

OBJECTIVE: Angiogenesis impairment is a common feature of diabetes mellitus (DM), whereas CD117+ bone marrow cells (BMCs) injury might be responsible for such complication. In this study, we studied the effect of hyperglycemia on the DNA damage and senility of CD117+ bone marrow cells. MATERIALS AND METHODS: We isolated CD117+ BMCs from the Streptozotocin (STZ) induced diabetes and healthy control mice. Oxidative stress was detected by flow cytometric analysis. γ-H2AX, which is the DNA damage mark, was detected by using Western blotting and immunofluorescence histochemistry. We also detected the expression of γ-H2AX and p16 by using Western blotting. RESULTS: Compared with the control mice, the level of reactive oxygen species (ROS) was increased significantly in the CD117+ BMCs collected from the diabetic mice (p<0.05), and the percentage of γ-H2AX positive cells was higher significantly (p<0.01). The expression of γ-H2AX and p16 was increased significantly in the CD117+ BMCs from the diabetic mice. CONCLUSIONS: Our experiments demonstrated the oxidative stress in CD117+ BMCs under DM conditions, while accelerating the DNA damage and senility in CD117+ BMCs as well.

Assessment of antidiabetic potential of Musa acuminata peel extract and its fractions in experimental animals and characterisation of its bioactive compounds by HPTLC.

Musa acuminata is a rich source of nutritional food with acclaimed therapeutic uses. Banana pulp has been reported to possess antidiabetic properties. The present study aimed to investigate antidiabetic potential of Musa acuminata peels and its fractions along with diabetic complications. Animals were divided into various groups (n = 6), EMA 100, 200 and 400 mg/kg/day and various fractions 50 and 100 mg/kg/day along with vehicle administered orally to alloxan-induced diabetic rats (n = 6) for 21 days for extract and for 7 days for fractions. Musa acuminata possess antidiabetic potential by reducing plasma glucose by utilising glucose in the periphery and production of hepatic glycogen and further reduce protein catabolism which is responsible for improvement in body weight along with reduction in diabetic complications such as dyslipidemia, peripheral neuropathy and nephropathy. Protective role of Musa acuminata in treatment of diabetes and its complications.

Fabrication and Biological Assessment of Antidiabetic α-Mangostin Loaded Nanosponges: In Vitro, In Vivo, and In Silico Studies.

Type 2 diabetes mellitus has been a major health issue with increasing morbidity and mortality due to macrovascular and microvascular complications. The urgent need for improved methods to control hyperglycemic complications reiterates the development of innovative preventive and therapeutic treatment strategies. In this perspective, xanthone compounds in the pericarp of the mangosteen fruit, especially α-mangostin (MGN), have been recognized to restore damaged pancreatic ß-cells for optimal insulin release. Therefore, taking advantage of the robust use of nanotechnology for targeted drug delivery, we herein report the preparation of MGN loaded nanosponges for anti-diabetic therapeutic applications. The nanosponges were prepared by quasi-emulsion solvent evaporation method. Physico-chemical characterization of formulated nanosponges with satisfactory outcomes was performed with Fourier transform infra-red (FTIR) spectroscopy, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Zeta potential, hydrodynamic diameter, entrapment efficiency, drug release properties, and stability studies at stress conditions were also tested. Molecular docking analysis revealed significant interactions of α-glucosidase and MGN in a protein-ligand complex. The maximum inhibition by nanosponges against α-glucosidase was observed to be 0.9352 ± 0.0856 µM, 3.11-fold higher than acarbose. In vivo studies were conducted on diabetic rats and plasma glucose levels were estimated by HPLC. Collectively, our findings suggest that MGN-loaded nanosponges may be beneficial in the treatment of diabetes since they prolong the antidiabetic response in plasma and improve patient compliance by slowly releasing MGN and requiring less frequent doses, respectively.

Revisiting definition and assessment of intestinal trans-epithelial passage.

This study aims to remind that Intestinal Passage (IP) measurement is a complex task that cannot be achieved by a unique measure of an orally given exogenous marker in blood or urine. This will be illustrated in the case of NOD mice. Indeed, various methods have been proposed to measure IP. Among them ex vivo measurement in Ussing chambers of luminal to serosal fluxes of exogenous markers and in vivo measurement of exogenous markers in blood or urine after oral gavage are the more commonly used. Even though they are commonly used indifferently, they do not give the same information and can provide contradictory results. Published data showed that diabetic status in female Non Obese Diabetic (NOD) mice increased FD4 concentration in blood after gavage but did not modify FD4 fluxes in Ussing chamber. We observed the same results in our experimental conditions and tracked FD4 concentrations in blood over a kinetic study (Area Under the Curve-AUC). In vivo measurements are a dynamic process and address not only absorption (IP and intestinal surface) but also distribution, metabolism and excretion (ADME). Diabetic status in NOD mice was associated with an increase of intestinal length (absorptive surface), itself positively correlated with AUC of FD4 in blood. We concluded that increased intestinal length induced by diabetic status will extend the absorptive surface and increase FD4 concentration in plasma (in vivo measurement) despite no modification on IP of FD4 (ex vivo measurement). In addition, this study characterized intestinal function in diabetic NOD mice. Diabetic status in NOD female mice increases intestinal length and decreases paracellular IP (FSS) without affecting transcellular IP (HRP, FD4). Histological studies of small and large intestine did not show any modification of intestinal circumference nor villi and crypt size. Finally, diabetic status was not associated with intestinal inflammation (ELISA).

Multi-strain probiotic supplement attenuates streptozotocin-induced type-2 diabetes by reducing inflammation and ß-cell death in rats.

Probiotics are health beneficial bacterial populations colonizing the human gut and skin. Probiotics are believed to be involved in immune system regulation, gut microbiota stabilization, prevention of infectious diseases, and adjustments of host metabolic activities. Probiotics such as Lactobacillus and Bifidobacterium affect glycemic levels, blood lipids, and protein metabolism. However, the interactions between probiotics and metabolic diseases as well as the underlying mechanisms remain unclear. We used streptozotocin (STZ)-induced diabetic animal models to study the effect of ProbiogluTM, a multi-strain probiotic supplement including Lactobaccilus salivarius subsp. salicinius AP-32, L. johnsonii MH-68, L. reuteri GL-104, and Bifidobacterium animalis subsp. lactis CP-9, on the regulation of physiochemical parameters related to type-2 diabetes. Experimental rats were randomly assigned into five groups, control group, streptozotocin (STZ)-treated rats (STZ group), STZ + 1× ProbiogluTM group, STZ + 5× ProbiogluTM group, and STZ + 10× ProbiogluTM group, and physiological data were measured at weeks 0, 2, 4, 6, and 8. Our results indicate that supplementation with ProbiogluTM significantly improved glucose tolerance, glycemic levels, insulin levels, and insulin resistance (HOMA-IR). Furthermore, we observed reduction in urea and blood lipid levels, including low-density lipoprotein (LDL), triglycerides (TG), and total cholesterol (TC). ProbiogluTM administration increased the ß-cell mass in STZ-induced diabetic animal models, whereas it reduced the levels of proinflammatory cytokines TNF-α, IL-6, and IL-1ß. In addition, the enhancement of oxidative stress biomarkers and superoxide dismutase (SOD) activities was associated with a decrease in malondialdehyde (MDA) levels. We conclude that ProbiogluTM attenuates STZ-induced type-2 diabetes by protecting ß-cells, stabilizing glycemic levels, and reducing inflammation. Among all probiotic treating groups, the 10×ProbiogluTM treatment revealed the best results. However, these experimental results still need to be validated by different animal models of type-2 diabetes and human clinical trials in the future.

The Role of Molecular and Inflammatory Indicators in the Assessment of Cognitive Dysfunction in a Mouse Model of Diabetes.

The brain is the most vulnerable organ to glucose fluctuations, as well as inflammation. Considering that cognitive impairment might occur at the early stage of diabetes, it is very important to identify key markers of early neuronal dysfunction. Our overall goal was to identify neuroinflammatory and molecular indicators of early cognitive impairment in diabetic mice. To confirm cognitive impairment in diabetic mice, series of behavioral tests were conducted. The markers related to cognitive decline were classified into the following two groups: Neuroinflammatory markers: IL-1ß, IL-6, tumor necrosis factor-α (TNF-α) and genetic markers (Bdnf, Arc, Egr1) which were estimated in brain regions. Our studies showed a strong association between hyperglycemia, hyperinsulinemia, neuroinflammation, and cognitive dysfunction in T2DM mice model. Cognitive impairment recorded in diabetes mice were associated not only with increased levels of cytokines but also decreased Arc and Egr1 mRNA expression level in brain regions associated with learning process and memory formation. The results of our research show that these indicators may be useful to test new forms of treatment of early cognitive dysfunction associated not only with diabetes but other diseases manifesting this type of disorders. The significant changes in Arc and Egr1 gene expression in early stage diabetes create opportunities it possible to use them to track the progression of CNS dysfunction and also to differential disease diagnosis running with cognitive impairment.

Assessment of insulin resistance in the skeletal muscle of mice using positron emission tomography/computed tomography imaging.

Measuring glucose uptake in the skeletal muscle in vivo is an effective method to determine glucose metabolism abnormalities as the skeletal muscle is the principal tissue responsible for glucose disposal and is a major site of peripheral insulin resistance. In this study, we investigated the pathological glucose metabolism dynamics of the skeletal muscle of C57BL/6J mice in a noninvasive and time-sequential manner using positron emission tomography/computed tomography (PET/CT), an imaging technique that uses radioactive substances to visualize and measure metabolic processes in the body, with [18F]-fluoro-2-deoxy-D-glucose (FDG). FDG-PET/CT imaging revealed that insulin administration and exercise load significantly increased FDG accumulation in the skeletal muscle of C57BL/6J mice. FDG accumulation was lower in the skeletal muscle of 14-week-old db/db diabetic model mice exhibiting remarkable insulin resistance compared to that of 7-week-old db/db mice. Based on the continuous observation of FDG accumulation over time in diet-induced obese (DIO) mice, FDG accumulation significantly decreased in 17-week-old mice after the acquisition of insulin resistance. Although insulin-induced glucose uptake in the skeletal muscle was markedly attenuated in 20-week-old DIO mice that had already developed insulin resistance, exercise load effectively increased FDG uptake in the skeletal muscle. Thus, we successfully confirmed that glucose uptake accompanied by insulin administration and exercise load increased in the skeletal muscle using PET-CT. FDG-PET/CT might be an effective tool that could noninvasively capture the chronological changes of metabolic abnormalities in the skeletal muscle of mice.

Glibenclamide nanosuspension inhaler: development, in vitro and in vivo assessment.

Objective: The development of nanosuspension for targeted delivery of glibenclamide as hypoglycemic agent to the lung in an inhaler dosage form.Method: Glibenclamide nanosuspension formulations were prepared using Box-Behnken design to investigate the effect of independent factors on the dependent variables, Fourier-transform Infrared spectroscopy, Differential Scanning Calorimetry, evaluation of glibenclamide nanosuspension inhaler and in vivo hypoglycemic efficacy were performed to determine glibenclamide nanosuspension inhaler effect.Results: The results revealed that the mean particle sizes of the prepared nanosuspension ranged from 0.216 to 0.856 µm, zeta potential from +9 to +16 mV, the solubility ranged from 43% to 75%, the mass median aerodynamic diameter was 2.34 µm and the glucose level in rat was significantly reduced by about 60%.Conclusion: These results confirmed that glibenclamide nanosuspension inhaler enhance hypoglycemic effectiveness and reduce adverse effect of glibenclamide, opening up new dosage form in Diabetes mellitus treatment.

Memory improvement by modafinil at cost of metabolic hazards? A study to decipher the benefits and risks of modafinil in rats.

BACKGROUND: Modafinil is approved for narcolepsy and achieved high success in off-label indications in memory-related disorders. However, chronic indiscriminate use of modafinil imposes several health hazards like hyperglycaemia, obesity and metabolic syndrome, owing to impairment of sleep-wake cycle, circadian-rhythm, and neurotransmission. The present protocol elucidates the effects of modafinil per se and diabetic complications apropos. METHODS: Modafinil (100 and 200 mg/kg) was administered in rats from day 5-26. To induce type-2 diabetes, streptozotocin (STZ) was given on day 1, and blood glucose assessed on day 5. CPP (combination propranolol and phentolamine) was administered to antagonize sympathetic activity. After evaluation of cognitive functions, serum lipid profile, and biomarkers of oxidative stress and acetylcholinesterase (AChE) activity were assessed. RESULTS: Subacute dosing of modafinil significantly elevated blood glucose levels, albeit considerably less than diabetic group, and attenuated brain oxidative stress and AChE activity. Modafinil caused significant dyslipidaemia, increased body weight, whereas modestly altered abdominal circumference (AC) and thoracic circumference (TC) in rats. Significant hyperglycaemia, derangement of serum lipid-profile, brain lipid peroxidation, cholinergic hypofunction, and decrease in body weight and ACTC was noted in diabetic rats. Modafinil (100 mg/kg) significantly potentiated the hyperglycaemia and dyslipidaemia, however, attenuated oxidative stress and AChE activity in diabetic rats. Modafinil increased short-term (working) memory but not long-term spatial memory in normal and diabetic rats. CPP infusion attenuated these effects of modafinil. CONCLUSION: Subacute dosing of modafinil differentially modulates long-term and short-term memory subtypes, and also predisposes towards metabolic derangements.

In vivo Assessment of Combined Effects of Glibenclamide and Losartan in Diabetic Rats.

OBJECTIVE: Diabetic complications involve multiple pathological pathways, including hyperglycemia-induced oxidative stress and inflammation. Combination therapy is usually employed to improve treatment outcomes and to lower potential adverse effects. In this study, we evaluated the effects of antidiabetic and antihypertensive agents, glibenclamide (GLI) and losartan (LT), on diabetes mellitus (DM)-associated metabolic changes in rats. MATERIALS AND METHODS: Streptozotocin-induced diabetic animals were orally treated with GLI 5 mg/kg and/or LT 25 mg/kg for 4 weeks. Blood glucose, insulin, aspartate aminotransferase, alanine aminotransferase, urinary creatinine, and urea levels were measured. Serum, liver, and kidney values of inflammatory markers, such as interleukin-1ß, tumor necrosis factor alpha, and interleukin-6 were assessed, along with lipid peroxidation products (e.g., thiobarbituric acid reactive substances), endogenous antioxidants (e.g., glutathione), as well as antioxidant enzyme activities (e.g., catalase, superoxide dismutase, and glutathione peroxidase). Finally, histological changes in liver and kidney tissues were evaluated. RESULTS: DM markedly induced systemic, hepatic, and renal inflammation and lowered antioxidant defense mechanisms. Treatment of diabetic rats with either GLI or LT significantly improved liver and kidney functions and histological structure. Moreover, both medications reduced signs of oxidative stress and inflammation in blood, liver, and kidney samples. Combining GLI and LT showed similar protective potential against systemic, hepatic, and renal oxidative stress and inflammation. CONCLUSION: Adding LT to GLI therapy revealed prospective antioxidant and anti-inflammatory action, while no synergistic or additive effects were observed.

Periostin and CCN2 Scaffolds Promote the Wound Healing Response in the Skin of Diabetic Mice.

IMPACT STATEMENT: Nonhealing skin wounds remain a significant burden on health care systems, with diabetic patients 20 times as likely to undergo a lower extremity amputation due to impaired healing. Novel treatments that suppress the proinflammatory signature and induce the proliferative and remodeling phases are needed clinically. We demonstrate that the addition of periostin and CCN2 in a scaffold form increases closure rates of full-thickness skin wounds in diabetic mice, concomitant with enhanced angiogenesis. Our results demonstrate the efficacy of periostin- and CCN2-containing biomaterials to stimulate wound closure, which could represent a novel method for the treatment of diabetic skin wounds.

Assessment of anti-diabetic activity of peanut shell polyphenol extracts.

The present study aimed to evaluate the anti-diabetic property of peanut shell polyphenol extracts (PSPEs). Diabetic rats were oral-administrated with PSPE at doses of 50, 100, and 200 mg/kg body weight (BW) per day for 28 consecutive days, with metformin (Met) as a positive control. The results showed that, similar to the Met treatment, administration of PSPE caused significant decreases in food intake, water intake, fasting blood glucose, total cholesterol, triglyceride, low-density lipoprotein cholesterol, and methane dicarboxylic aldehyde in serum, and significant increases in BW, insulin level, high-density lipoprotein cholesterol, superoxide dismutase, glutathione, and liver glycogen. Further, glucose tolerance was markedly improved in the PSPE-treated diabetic groups. Histopathological results showed that PSPE improved cellular structural and pathological changes in liver, kidney, and pancreatic islets. Collectively, the results indicated that the hypoglycemic effects of PSPE on high-fat diet/streptozotocin (HFD/STZ)-induced diabetes are comparable to Met, though their exact mechanism actions are still under investigation. Therefore, the current study suggests that PSPE could be a potential health-care food supplement in the management of diabetes.

Magnetoliposomes as Contrast Agents for Longitudinal in vivo Assessment of Transplanted Pancreatic Islets in a Diabetic Rat Model.

Magnetoliposomes (MLs) were synthesized and tested for longitudinal monitoring of transplanted pancreatic islets using magnetic resonance imaging (MRI) in rat models. The rat insulinoma cell line INS-1E and isolated pancreatic islets from outbred and inbred rats were used to optimize labeling conditions in vitro. Strong MRI contrast was generated by islets exposed to 50 µg Fe/ml for 24 hours without any increased cell death, loss of function or other signs of toxicity. In vivo experiments showed that pancreatic islets (50-1000 units) labeled with MLs were detectable for up to 6 weeks post-transplantation in the kidney subcapsular space. Islets were also monitored for two weeks following transplantation through the portal vein of the liver. Hereby, islets labeled with MLs and transplanted under the left kidney capsule were able to correct hyperglycemia and had stable MRI signals until nephrectomy. Interestingly, in vivo MRI of streptozotocin induced diabetic rats transplanted with allogeneic islets demonstrated loss of MRI contrast between 7-16 days, indicative of loss of islet structure. MLs used in this study were not only beneficial for monitoring the location of transplanted islets in vivo with high sensitivity but also reported on islet integrity and hereby indirectly on islet function and rejection.

Isoalantolactone derivative promotes glucose utilization in skeletal muscle cells and increases energy expenditure in db/db mice via activating AMPK-dependent signaling.

Augmenting glucose utilization and energy expenditure in skeletal muscle via AMP-activated protein kinase (AMPK) is an imperative mechanism for the management of type 2 diabetes. Chemical derivatives (2a-2h, 3, 4a-4d, 5) of the isoalantolactone (K007), a bioactive molecule from roots of Inula racemosa were synthesized to optimize the bioactivity profile to stimulate glucose utilization in skeletal muscle cells. Interestingly, 4a augmented glucose uptake, driven by enhanced translocation of glucose transporter 4 (GLUT4) to cell periphery in L6 rat skeletal muscle cells. The effect of 4a was independent to phosphatidylinositide-3-kinase (PI-3-K)/Akt pathway, but mediated through Liver kinase B1 (LKB1)/AMPK-dependent signaling, leading to activation of downstream targets acetyl coenzyme A carboxylase (ACC) and sterol regulatory element binding protein 1c (SREBP-1c). In db/db mice, 4a administration decreased blood glucose level and improved body mass index, lipid parameters and glucose tolerance associated with elevation of GLUT4 expression in skeletal muscle. Moreover, 4a increased energy expenditure via activating substrate utilization and upregulated the expression of thermogenic transcription factors and mitochondrial proteins in skeletal muscle, suggesting the regulation of energy balance. These findings suggest the potential implication of isoalantolactone derivatives for the management of diabetes.

Assessment of the Anti-Hyperglycaemic, Anti-Inflammatory and Antioxidant Activities of the Methanol Extract of Moringa Oleifera in Diabetes-Induced Nephrotoxic Male Wistar Rats.

Diabetes mellitus is an endocrine disease of multiple aetiologies in insulin secretion. A deficiency in insulin results in hyperglycemia with metabolic disturbances of biomolecules. Moringa oleifera (MO) is endemic in the tropics with a variety of ethnomedicinal importance. The leaf of this plant has been reported to possess antioxidant and medicinal properties that may be helpful in the treatment and management of diabetes and its associated complications. Diabetes was induced intraperitoneally in rats by a single dose of streptozotocin (55 mg/kg) and treated with methanolic extract of Moringa oleifera (250 mg/kg b.wt) for six weeks. Forty-eight (48) adult male Wistar strain rats were randomly divided into four groups: normal control (NC), Moringa oleifera treated control rats (NC + MO), diabetic rats (DM) and Moringa oleifera treated diabetic rats (DM + MO). Estimation of antioxidant capacity, total polyphenols, flavonoids and flavonols content of Moringa oleifera extract was performed and serum biochemical markers were evaluated. Antioxidants such as catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD) activities, glutathione (GSH) and inflammatory biomarkers were determined in the kidney. Results showed high antioxidant capacities of MO extract and improved serum biochemical markers, whilst lipid peroxidation (MDA) levels were reduced in non-diabetic and diabetic rats after MO treatment when compared to normal control. Subsequent administration of MO led to an increased concentration of serum albumin, globulin and total protein with a decrease in the level of MDA, and improvements in CAT, SOD, GSH, GPx, (tumour necrosis factor-alpha)TNF-α and (interleukin-6)IL-6. MO contains potent phytochemical constituents that offer protective action against diabetic-induced renal damage, reactive oxygen species (ROS) and inflammation and could therefore play a role in reducing diabetic complications, particularly in developing countries such as in Africa where the majority cannot afford orthodox medicine.

Expression and Purification of C-Peptide Containing Insulin Using Pichia pastoris Expression System.

Increase in the incidence of Insulin Dependent Diabetes Mellitus (IDDM) among people from developed and developing countries has created a large global market for insulin. Moreover, exploration of new methods for insulin delivery including oral or inhalation route which require very high doses would further increase the demand of cost-effective recombinant insulin. Various bacterial and yeast strains have been optimized to overproduce important biopharmaceuticals. One of the approaches we have taken is the production of recombinant human insulin along with C-peptide in yeast Pichia pastoris. We procured a cDNA clone of insulin from Origene Inc., USA. Insulin cDNA was PCR amplified and cloned into yeast vector pPICZ-α. Cloned insulin cDNA was confirmed by restriction analysis and DNA sequencing. pPICZ-α-insulin clone was transformed into Pichia pastoris SuperMan 5 strain. Several Zeocin resistant clones were obtained and integration of insulin cDNA in Pichia genome was confirmed by PCR using insulin specific primers. Expression of insulin in Pichia clones was confirmed by ELISA, SDS-PAGE, and Western blot analysis. In vivo efficacy studies in streptozotocin induced diabetic mice confirmed the activity of recombinant insulin. In conclusion, a biologically active human proinsulin along with C-peptide was expressed at high level using Pichia pastoris expression system.

Effect of canagliflozin and metformin on cortical neurotransmitters in a diabetic rat model.

BACKGROUND: The rapid economic development in the Arabian Gulf has resulted in lifestyle changes that have increased the prevalence of obesity and type 2 diabetes, with the greatest increases observed in Kuwait. Dyslipidemia and diabetes are risk factors for disruptions in cortical neurotransmitter homeostasis. This study investigated the effect of the antidiabetic medications canagliflozin (CAN) and metformin (MET) on the levels of cortical neurotransmitters in a diabetic rat model. MATERIALS AND METHODS: The rats were assigned to the control (C) group, the diabetic group that did not receive treatment (D) or the diabetic group treated with either CAN (10 mg/kg) or MET (100 mg/kg) for 2 or 4 weeks. Blood and urine glucose levels and cortical acetylcholinesterase (AChE) activity were assayed, and amino acid and monoamine levels were measured using HPLC. RESULTS: The diabetic group exhibited a significant increase in AChE activity and a decrease in monoamine and amino acid neurotransmitter levels. In the CAN group, AChE was significantly lower than that in the D and D + MET groups after 2 weeks of treatment. In addition, a significant increase in some cortical monoamines and amino acids was observed in the D + MET and D + CAN groups compared with the D group. Histopathological analysis revealed the presence of severe focal hemorrhage, neuronal degeneration, and cerebral blood vessel congestion, with gliosis in the cerebrum of rats in the D group. The CAN-treated group exhibited severe cerebral blood vessel congestion after 2 weeks of treatment and focal gliosis in the cerebrum after 4 weeks of treatment. Focal gliosis in the cerebrum of rats in the MET-treated group was observed after 2 and 4 weeks of treatment. CONCLUSIONS: We conclude that the effect of CAN and MET on neurotransmitters is potentially mediated by their antihyperglycemic and antihyperlipidemic effects. In addition, the effects of CAN on neurotransmitters might be associated with its receptor activity, and the effect of MET on neurotransmitters might be associated with cerebral metabolism.