Intranasal oxytocin fails to acutely improve glucose metabolism in obese men

The hypothalamic neuropeptide oxytocin not only modulates psychosocial function, but also contributes to metabolic regulation. We have recently shown that intranasal oxytocin acutely improves beta-cell responsivity and glucose tolerance in normal-weight men. In the present experiment, we investigated the acute glucoregulatory impact of oxytocin in obese men with impaired insulin sensitivity. Fifteen obese healthy men with an average body mass index of 35 kg/m² and an average body fat content of 33% received a single intranasal dose (24 IU) of oxytocin before undergoing an oral glucose tolerance test. Results were analysed according to the oral minimal model and compared with our findings in normal-weight participants. In contrast to the results in normal-weight subjects, oxytocin did not blunt postprandial glucose and insulin excursions in obese men, and moreover failed to enhance beta-cell responsivity and glucose tolerance. These results indicate that pronounced obesity may be associated with a certain degree of resistance to the glucoregulatory impact of exogenous oxytocin, and underlines the need for further investigations into the potential of oxytocin to improve glucose homeostasis in the clinical context.

Effects of AM80 compared to AC261066 in a high fat diet mouse model of liver disease

The roles of retinoids in nonalcoholic fatty liver disease (NAFLD) remain unclear and a better understanding may lead to therapies that prevent or limit NAFLD progression. We examined the actions of retinoic acid receptor (RAR) agonists- AM80 for RARα and AC261066 for RARβ2- in a murine model of NAFLD. We fed wild type C57Bl/6 mice a chow or a 45% high fat diet (HFD) for 12 weeks, followed by 4 additional weeks with the HFD+AM80; HFD+AC261066; or HFD. The HFD+AM80 group showed greater hyperglycemia and glucose intolerance compared to other groups. Histopathological evaluation of the livers showed the highest degree of steatosis, triglycerides levels, and inflammation, assessed by F4/80 staining, in the HFD+AM80-treated compared to the HFD, the HFD+AC261066, and chow-fed mice. Liver vitamin A (retinol (ROL)) and retinyl palmitate levels were markedly lower in all HFD groups compared to chow-fed controls. HFD+AC261066-treated mice showed higher levels of a key intracellular ROL transporter, retinol-binding protein-1 (RBP1) compared to the HFD and HFD+AM80 groups. In conclusion, these data demonstrate that the selective RARα agonist AM80 exacerbates HFD-induced NAFLD and hyperglycemia. These findings should inform future studies examining the therapeutic potential of RAR agonists in HFD-related disorders.

Beneficial Effects of Vitamin D Treatment in an Obese Mouse Model of Non-Alcoholic Steatohepatitis

Serum vitamin D levels negatively correlate with obesity and associated disorders such as non-alcoholic steatohepatitis (NASH). However, the mechanisms linking low vitamin D (VD) status to disease progression are not completely understood. In this study, we analyzed the effect of VD treatment on NASH in mice. C57BL6/J mice were fed a high-fat/high-sugar diet (HFSD) containing low amounts of VD for 16 weeks to induce obesity, NASH and liver fibrosis. The effects of preventive and interventional VD treatment were studied on the level of liver histology and hepatic/intestinal gene expression. Interestingly, preventive and to a lesser extent also interventional VD treatment resulted in improvements of liver histology. This included a significant decrease of steatosis, a trend towards lower non-alcoholic fatty liver disease (NAFLD) activity score and a slight non-significant decrease of fibrosis in the preventive treatment group. In line with these changes, preventive VD treatment reduced the hepatic expression of lipogenic, inflammatory and pro-fibrotic genes. Notably, these beneficial effects occurred in conjunction with a reduction of intestinal inflammation. Together, our observations suggest that timely initiation of VD supplementation (preventive vs. interventional) is a critical determinant of treatment outcome in NASH. In the applied animal model, the improvements of liver histology occurred in conjunction with reduced inflammation in the gut, suggesting a potential relevance of vitamin D as a therapeutic agent acting on the gut⁻liver axis.

Effects of Highly Absorbable Curcumin in Patients with Impaired Glucose Tolerance and Non-Insulin-Dependent Diabetes Mellitus

Oxidative stress is enhanced by various mechanisms. Serum oxidized low-density lipoprotein (LDL) is a useful prognostic marker in diabetic patients with coronary artery disease. To examine the effects of Theracurmin®, a highly absorbable curcumin preparation, on glucose tolerance, adipocytokines, and oxidized LDL, we conducted a double-blind placebo-controlled parallel group randomized trial in patients with impaired glucose tolerance or non-insulin-dependent diabetes mellitus. We randomly divided the patients with impaired glucose tolerance or non-insulin-dependent diabetes mellitus and stable individuals into the placebo group and the Theracurmin® (180 mg daily for 6 months) group. Of the 33 patients analyzed, 18 (14 males and 4 females) were administered placebo and 15 (9 males and 6 females) were administered Theracurmin®. The patient characteristics did not differ between the two groups. The primary endpoint, HbA1c, did not differ significantly between the two groups. However, the level of α1-antitrypsin-low-density lipoprotein (AT-LDL), the oxidized LDL, significantly increased (p = 0.024) in the placebo group from the beginning of the trial up to 6 months, although there was no such change in the Theracurmin® group. The percentage change in BMI from the beginning of the trial up to 6 months tended to be higher in the Theracurmin® group than in the placebo group. Patients in the Theracurmin® group tended to have a larger percentage change in adiponectin and LDL-C than those in the placebo group. Patients in the Theracurmin® group showed a smaller percentage change in AT-LDL than those in the placebo group. This study suggests that the highly absorbable curcumin could potentially inhibit a rise in oxidized LDL in patients with impaired glucose tolerance or non-insulin-dependent diabetes mellitus. This trial is registered with UMIN000007361.

Alpha-glucosidase inhibitors for prevention or delay of type 2 diabetes mellitus and its associated complications in people at increased risk of developing type 2 diabetes mellitus

BACKGROUND

Alpha-glucosidase inhibitors (AGI) reduce blood glucose levels and may thus prevent or delay type 2 diabetes mellitus (T2DM) and its associated complications in people at risk of developing of T2DM.

OBJECTIVES

To assess the effects of AGI in people with impaired glucose tolerance (IGT), impaired fasting blood glucose (IFG), moderately elevated glycosylated haemoglobin A1c (HbA1c) or any combination of these.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform, and the reference lists of systematic reviews, articles and health technology assessment reports. The date of the last search of all databases was December 2017.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), with a duration of one year or more, comparing AGI with any pharmacological glucose-lowering intervention, behaviour-changing intervention, placebo or no intervention in people with IFG, IGT, moderately elevated HbA1c or combinations of these.

DATA COLLECTION AND ANALYSIS

Two review authors read all abstracts and full-text articles or records, assessed quality and extracted outcome data independently. One review author extracted data, which were checked by a second review author. We resolved discrepancies by consensus or involvement of a third review author. For meta-analyses we used a random-effects model with assessment of risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes, using 95% confidence intervals (CIs) for effect estimates. We assessed the overall quality of the evidence by using the GRADE instrument.

MAIN RESULTS

For this update of the Cochrane Review (first published 2006, Issue 4) we included 10 RCTs (11,814 participants), eight investigating acarbose and two investigating voglibose, that included people with IGT or people "at increased risk for diabetes". The trial duration ranged from one to six years. Most trials compared AGI with placebo (N = 4) or no intervention (N = 4).Acarbose reduced the incidence of T2DM compared to placebo: 670 out of 4014 people (16.7%) in the acarbose groups developed T2DM, compared to 812 out of 3994 people (20.3%) in the placebo groups (RR 0.82, 95% CI 0.75 to 0.89; P < 0.0001; 3 trials; 8008 participants; moderate-certainty evidence). One trial including participants with coronary heart disease and IGT contributed 64% of cases for this outcome. Acarbose reduced the risk of T2DM compared to no intervention: 7 out 75 people (9.3%) in the acarbose groups developed T2DM, compared to 18 out of 65 people (27.7%) in the no-intervention groups (RR 0.31, 95% CI 0.14 to 0.69; P = 0.004; 2 trials; 140 participants; very low-certainty evidence).Acarbose compared to placebo did not reduce or increase the risk of all-cause mortality (RR 0.98, 95% CI 0.82 to 1.18; P = 0.86; 3 trials; 8069 participants; very low-certainty evidence), cardiovascular mortality (RR 0.88; 95% CI 0.71 to 1.10; P = 0.26; 3 trials; 8069 participants; very low-certainty evidence), serious adverse events (RR 1.12, 95% CI 0.97 to 1.29; P = 0.13; 2 trials; 6625 participants; low-certainty evidence), non-fatal stroke (RR 0.50, 95% CI 0.09 to 2.74; P = 0.43; 1 trial; 1368 participants; very low-certainty evidence) or congestive heart failure (RR of 0.87; 95% CI 0.63 to 1.12; P = 0.40; 2 trials; 7890 participants; low-certainty evidence). Acarbose compared to placebo reduced non-fatal myocardial infarction: one out of 742 participants (0.1%) in the acarbose groups had a non-fatal myocardial infarction compared to 15 out of 744 participants (2%) in the placebo groups (RR 0.10, 95% CI 0.02 to 0.53; P = 0.007; 2 trials; 1486 participants; very low-certainty evidence). Acarbose treatment showed an increased risk of non-serious adverse events (mainly gastro-intestinal events), compared to placebo: 751 of 775 people (96.9%) in the acarbose groups experienced an event, compared to 723 of 775 people (93.3%) in the placebo groups (RR 1.04; 95% CI 1.01 to 1.06; P = 0.0008; 2 trials; 1550 participants). Acarbose compared to no intervention showed no advantage or disadvantage for any of these outcome measures (very low-certainty evidence).One trial each compared voglibose with placebo (1780 participants) or diet and exercise (870 participants). Voglibose compared to placebo reduced the incidence of T2DM: 50 out of 897 participants (5.6%) developed T2DM, compared to 106 out of 881 participants (12%) in the placebo group (RR 0.46, 95% CI 0.34 to 0.64; P < 0.0001; 1 trial; 1778 participants; low-certainty evidence). For all other reported outcome measures there were no clear differences between voglibose and comparator groups. One trial with 90 participants compared acarbose with diet and exercise and another trial with 98 participants reported data on acarbose versus metformin. There were no clear differences for any outcome measure between these two acarbose interventions and the associated comparator groups.None of the trials reported amputation of lower extremity, blindness or severe vision loss, end-stage renal disease, health-related quality of life, time to progression to T2DM, or socioeconomic effects.

AUTHORS' CONCLUSIONS

AGI may prevent or delay the development of T2DM in people with IGT. There is no firm evidence that AGI have a beneficial effect on cardiovascular mortality or cardiovascular events.

Glimepiride Administered in Chow Reversibly Impairs Glucose Tolerance in Mice

Sulfonylureas are a class of antidiabetes medications prescribed to millions of individuals worldwide. Rodents have been used extensively to study sulfonylureas in the laboratory. Here, we report the results of studies treating mice with a sulfonylurea (glimepiride) in order to understand how the drug affects glucose homeostasis and tolerance. We tested the effect of glimepiride on fasting blood glucose, glucose tolerance, and insulin secretion, using glimepiride sourced from a local pharmacy. We also examined the effect on glucagon, gluconeogenesis, and insulin sensitivity. Unexpectedly, glimepiride exposure in mice was associated with fasting hyperglycemia, glucose intolerance, and decreased insulin. There was no change in circulating glucagon levels or gluconeogenesis. The effect was dose-dependent, took effect by two weeks, and was reversed within three weeks after removal. Glimepiride elicited the same effects in all strains evaluated: four wild-type strains, as well as the transgenic Grn-/- and diabetic db/db mice. Our findings suggest that the use of glimepiride as a hypoglycemic agent in mice should proceed with caution and may have broader implications about mouse models as a proxy to study the human pharmacopeia.

Southern Brazilian native fruit shows neurochemical, metabolic and behavioral benefits in an animal model of metabolic syndrome

In this work, we evaluated the effects of Psidium cattleianum (Red Type) (PcRT) fruit extract on metabolic, behavioral, and neurochemical parameters in rats fed with a highly palatable diet (HPD) consisted of sucrose (65% carbohydrates being 34% from condensed milk, 8% from sucrose and 23% from starch, 25% protein and 10% fat). Animals were divided into 4 groups: standard chow, standard chow + PcRT extract (200 mg/Kg/day by gavage), HPD, HPD + extract. The animals were treated for 150 days. Concerning chemical profiling, LC/PDA/MS/MS analysis revealed cyanidin-3-O-glucoside as the only anthocyanin in the PcRT extract. Our results showed that the animals exposed to HPD presented glucose intolerance, increased weight gain and visceral fat, as well as higher serum levels of glucose, triacylglycerol, total cholesterol, LDL-cholesterol and interleukin-6. These alterations were prevented by PcRT. In addition, HPD caused an increase in immobility time in a forced swimming test and the fruit extract prevented this alteration, indicating an antidepressant-like effect. PcRT treatment also prevented increased acetylcholinesterase activity in the prefrontal cortex caused by HPD consumption. Moreover, PcRT extract was able to restore Ca²⁺-ATPase activity in the prefrontal cortex, hippocampus, and striatum, as well as Na⁺,K⁺-ATPase activity in the prefrontal cortex and hippocampus. PcRT treatment decreased thiobarbituric acid-reactive substances, nitrite, and reactive oxygen species levels and prevented the reduction of superoxide dismutase activity in all cerebral structures of the HPD group. Additionally, HPD decreased catalase in the hippocampus and striatum. However, the extract prevented this change in the hippocampus. Our results showed that this berry extract has antihyperglycemic and antihyperlipidemic effects, and neuroprotective properties, proving to be a potential therapeutic agent for individuals with metabolic syndrome.

A Slow-Digesting, Low-Glycemic Load Nutritional Beverage Improves Glucose Tolerance in Obese Pregnant Women Without Gestational Diabetes

BACKGROUND

Obesity is a risk factor for gestational diabetes (gestational diabetes). Low-glycemic index diets attenuate hyperglycemia. We designed a study to determine whether a slow-digesting, low-glycemic load (SD-LGL) beverage improves glucose tolerance in obese pregnant women without GDM.

METHODS

This was a 3-arm comparison study comparing the effects of an SD-LGL nutritional beverage (glycemic load [GL] 730), an isocaloric control beverage (GL 1124), and habitual diet on glycemia in obese pregnant women. Sixteen women (mean body mass index 37 kg/m²) were recruited at 24-28 weeks to receive either the SD-LGL or eucaloric control beverage. This was consumed with breakfast and as a midafternoon snack over 2 days with a controlled diet. Following a 2-day washout period of habitual diet, women completed 2 days on the alternative beverage with controlled diet. A 10-h fast preceded each intervention phase. Twenty-four hour glucose was measured using continuous glucose monitoring.

RESULTS

Consumption of the lower GL beverage was associated with improved measures of glycemia, compared with the control beverage and habitual diet at different time periods. Glucose estimates for control versus SD-LDL at 24 h (0.23 mmol/L [0.16 to 0.31], P < 0.001), daytime (0.26 mmol/L [0.18 to 0.34], P < 0.001), and nighttime (0.05 mmol/L [-0.01 to 0.11], P = 0.09). Postprandial glucose was lower after breakfast but not after dinner, compared with the control beverage (0.09 mmol/L [0.01 to 0.18], P = 0.03).

CONCLUSION

A slow-digesting, low-glycemic nutritional beverage may facilitate improved glucose control in obese pregnant women. To address potential benefit for clinical outcomes, a randomized controlled trial is warranted.

Relationship between serum adipsin and the first phase of glucose-stimulated insulin secretion in individuals with different glucose tolerance

AIMS/INTRODUCTION

To detect serum adipsin levels in individuals with different glucose tolerance, and investigate the relationship between adipsisn and the first phase of insulin secretion.

MATERIALS AND METHODS

A total of 56 patients with newly diagnosed type 2 diabetes mellitus, 36 patients with impaired glucose tolerance (IGT) and 45 individuals with normal glucose tolerance were enrolled. Intravenous glucose tolerance tests were carried out to evaluate pancreatic β-cell function. The serum levels of adipsin, interleukin-1β and high-sensitivity C-reactive protein were assayed.

RESULTS

Serum adipsin levels were significantly lower in the type 2 diabetes mellitus and the IGT patients than those in the normal glucose tolerance group (P < 0.05). The acute insulin response and area under the curve showed a progressive decrease in the normal glucose tolerance and IGT groups, and decreased to the lowest levels in the type 2 diabetes mellitus group (P < 0.05). Adipsin was found to be negatively correlated with waist-to-hip ratio, free fatty acid, fasting plasma glucose, 2-h postprandial plasma glucose, glycated hemoglobin, homeostasis model assessment of insulin resistance, interleukin-1β and high-sensitivity C-reactive protein (P < 0.05 or P < 0.001), and positively correlated with homeostasis model assessment of β-cell function, high-density lipoprotein cholesterol, the area under the curve of the first phase insulin secretion and acute insulin response (P < 0.05 or P < 0.001). Stepwise multiple regression analysis showed that homeostasis model assessment for β-cell function and acute insulin response were independently related to adipsin (P < 0.05).

CONCLUSIONS

Serum adipsin levels were lower in type 2 diabetes mellitus and IGT patients, and correlated with the first phase of insulin secretion. Adipsin might be involved in the pathology of type 2 diabetes mellitus.

Chromium Supplementation Reduces Resting Heart Rate in Patients with Metabolic Syndrome and Impaired Glucose Tolerance

Chromium (Cr) is considered as an important mineral, involved in biochemical reactions in human metabolic pathways. Organically bound Cr supplementation has been suggested to improve glycemia especially in patients with type 2 diabetes mellitus, but there are conflicting reports on efficacy. Effect of Cr is not clear in prediabetes status. Seventy patients with metabolic syndrome and impaired glucose tolerance (IGT), who are observed and treated in the Center of Preventive Cardiology of the University Hospital in Pilsen, were included in the prospective, randomized, double-blind, and placebo-controlled clinical study. Effect of Cr-enriched yeast (200 μg of elementary Cr in the morning and 100 μg in the evening) on glucose, lipid metabolism, fat tissue hormones, oxidative stress, and DNA damage markers was analyzed. There were no significant changes in glucose and lipid parameters, oxidative stress, or other laboratory markers. Only resting heart rate was significantly reduced in patients treated by Cr yeast, reflecting reduced sympathetic activity. This could represent an important cardiovascular risk reduction in patients with high cardiometabolic risk.

Sarcopoterium spinosum extract improved insulin sensitivity in mice models of glucose intolerance and diabetes

BACKGROUND

The glucose lowering properties of Sarcopoterium spinosum, a traditional medicinal plant, were previously validated by us using KK-Ay mice as a genetic model for type 2 diabetes (T2D).

OBJECTIVE

To clarify the effects of Sarcopoterium spinosum extract (SSE) on diet-induced glucose intolerance and to investigate SSE effects on carbohydrate and lipid metabolism in target tissues of both high-fat-diet (HFD)-fed and KK-Ay mice.

RESULTS

Mice were given SSE (70 mg/day) for 6 weeks. SSE improved glucose tolerance and insulin sensitivity in HFD-fed mice as was demonstrated previously in KK-Ay mice. Higher insulin sensitivity was validated by lower serum insulin and activation of the insulin signaling cascade in skeletal muscle and liver of SSE-treated mice in both models. H&E staining of the livers demonstrated lower severity of steatosis in SSE-treated mice. Several model-specific effects of SSE were observed-mRNA expression of proinflammatory genes and CD36 was reduced in SSE-treated KK-Ay mice. Hepatic mRNA expression of PEPCK was also reduced in SSE-treated KK-Ay mice, while other genes involved in carbohydrates and lipid metabolism were not affected. HFD-fed mice treated by SSE had elevated hepatic glycogen stores. Gluconeogenic gene expression was not affected, while GCK expression was increased. HFD-induced hepatic steatosis was not affected by SSE. However, while genes involved in lipid metabolism were downregulated by HFD, this was not found in HFD-fed mice given SSE, demonstrating an expression profile which is similar to that of standard diet-fed mice.

CONCLUSION

Our study supports the insulin sensitizing activity of SSE and suggests that this extract might improve other manifestations of the metabolic syndrome.

A vitamin B12 conjugate of exendin-4 improves glucose tolerance without associated nausea or hypophagia in rodents

AIMS

While pharmacological glucagon-like peptide-1 receptor (GLP-1R) agonists are FDA-approved for treating type 2 diabetes mellitus (T2DM) and obesity, a major side effect is nausea/malaise. We recently developed a conjugate of vitamin B12 (B12) bound to the GLP-1R agonist exendin-4 (Ex4), which displays enhanced proteolytic stability and retention of GLP-1R agonism. Here, we evaluate whether the conjugate (B12-Ex4) can improve glucose tolerance without producing anorexia and malaise.

MATERIALS AND METHODS

We evaluated the effects of systemic B12-Ex4 and unconjugated Ex4 on food intake and body weight change, oral glucose tolerance and nausea/malaise in male rats, and on intraperitoneal glucose tolerance in mice. To evaluate whether differences in the profile of effects of B12-Ex4 vs unconjugated Ex4 are the result of altered CNS penetrance, rats received systemic injections of fluorescein-Ex4 (Flex), Cy5-B12 or Cy5-B12-Ex4 and brain penetrance was evaluated using confocal microscopy. Uptake of systemically administered Cy5-B12-Ex4 in insulin-containing pancreatic beta cells was also examined.

RESULTS

B12-Ex4 conjugate improves glucose tolerance, but does not elicit the malaise and anorexia produced by unconjugated Ex4. While Flex robustly penetrates into the brain (dorsal vagal complex, paraventricular hypothalamus), Cy5-B12 and Cy5-B12-Ex4 fluorescence were not observed centrally, supporting an absence of CNS penetrance, in line with observed reduction in CNS-associated Ex4 side effects. Cy5-B12-Ex4 colocalizes with insulin in the pancreas, suggesting direct pancreatic action as a potential mechanism underlying the hypoglycaemic effects of B12-Ex4.

CONCLUSION

These novel findings highlight the potential clinical utility of B12-Ex4 conjugates as possible future T2DM therapeutics with reduced incidence of adverse effects.

Updates in Stroke Treatment

In this article, we discuss major advances in the treatment and prevention of ischemic stroke that have taken placed in the past 3 years. The most important advance in acute stroke treatment is the validation and widespread adoption of intra-arterial therapies for the treatment of acute ischemic stroke. Five clinical trials spanning multiple continents were published in early 2015 that proved that intra-arterial treatment - both with and without tPA - is beneficial in improving functional recovery after stroke. Emerging literature (including the DAWN trial) also suggests that patients can be treated up to 24 hours after the onset of symptoms based on the size of the infarct core obtained using MRI Perfusion or CT Perfusion imaging. With respect to stroke secondary prevention, widespread adoption of long-term cardiac monitoring has increased the detection rate of atrial fibrillation (as demonstrated in the EMBRACE and CRYSTAL-AF trials). Pioglitazone (an oral hypoglycemic agent of the thiazolidinedione drug class) was shown in the IRIS trial to reduce the risk of recurrent stroke in patients with impaired glucose tolerance who had not developed type 2 diabetes mellitus.

Compound K attenuates glucose intolerance and hepatic steatosis through AMPK-dependent pathways in type 2 diabetic OLETF rats

BACKGROUND/AIMS

Non-alcoholic fatty liver disease is associated with insulin resistance. Compound K (CK) is the final metabolite of panaxadiol ginsenosides that have been shown to exert antidiabetic effects. However, the molecular mechanism of the antidiabetic effects in the liver have not been elucidated; further, whether CK has beneficial effects in hepatosteatosis remains unclear. Therefore, we evaluated the effect of CK on hepatosteatosis as well as its mechanism in high-fat diet (HFD)-fed type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats.

METHODS

Twenty-four-week-old male OLETF rats were assigned to four groups: control (saline), CK 10 mg/kg, CK 25 mg/kg, or metformin 300 mg/kg (positive control); all treatments were administered orally for 12 weeks.

RESULTS

Fasting glucose levels of the CK25 group were significantly lower than those of the control group during the 12 weeks. The results of the oral glucose tolerance test showed that both the glucose concentration after glucose loading and the fasting insulin levels of the CK25 group were significantly lower than those of the control. Hepatosteatosis was significantly improved by CK25. CK25 and metformin significantly increased the phosphorylation of hepatic adenosine monophosphate-activated protein kinase (AMPK). CK25 significantly inhibited the expression of sterol regulatory element-binding protein-1c and fatty acid synthase, while upregulating that of peroxisome proliferator-activated receptor-α and carnitine palmitoyltransferase-1.

CONCLUSIONS

CK improved glucose intolerance and hepatosteatosis in HFD-fed OLETF rats through AMPK activation, which has dual mode of action that involves decreasing the synthesis of fatty acids and increasing fatty acid oxidation.

Pancreatic Pericytes Support β-Cell Function in a Tcf7l2-Dependent Manner

Polymorphism in TCF7L2, a component of the canonical Wnt signaling pathway, has a strong association with β-cell dysfunction and type 2 diabetes through a mechanism that has yet to be defined. β-Cells rely on cells in their microenvironment, including pericytes, for their proper function. Here, we show that Tcf7l2 activity in pancreatic pericytes is required for β-cell function. Transgenic mice in which Tcf7l2 was selectively inactivated in their pancreatic pericytes exhibited impaired glucose tolerance due to compromised β-cell function and glucose-stimulated insulin secretion. Inactivation of pericytic Tcf7l2 was associated with impaired expression of genes required for β-cell function and maturity in isolated islets. In addition, we identified Tcf7l2-dependent pericytic expression of secreted factors shown to promote β-cell function, including bone morphogenetic protein 4 (BMP4). Finally, we show that exogenous BMP4 is sufficient to rescue the impaired glucose-stimulated insulin secretion of transgenic mice, pointing to a potential mechanism through which pericytic Tcf7l2 activity affects β-cells. To conclude, we suggest that pancreatic pericytes produce secreted factors, including BMP4, in a Tcf7l2-dependent manner to support β-cell function. Our findings thus propose a potential cellular mechanism through which abnormal TCF7L2 activity predisposes individuals to diabetes and implicates abnormalities in the islet microenvironment in this disease.

Evaluation of the Chinese herbal medicine Jinlida in type 2 diabetes patients based on stratification: Results of subgroup analysis from a 12-week trial

BACKGROUND

The Chinese herbal medicine Jinlida can significantly enhance the hypoglycemic action of metformin. However, the population showing the best responses to Jinlida has not been clarified. The aim of the present study was to compare the efficacy of Jinlida in type 2 diabetes mellitus (T2DM) after stratification.

METHODS

Data were analyzed from a 12-week randomized placebo-controlled double-blind multicenter study with 192 T2DM patients (186 completed the study). The efficacy evaluation included HbA1c, fasting plasma glucose (FPG), and 2-h postprandial glucose (2hPG) levels stratified by baseline HbA1c, sex, age, body mass index (BMI), and duration of T2DM diagnosis. Homeostasis model assessment of insulin resistance (HOMA-IR) and homeostatic model assessment of β-cell function (HOMA-β) were also evaluated stratified by baseline insulin levels.

RESULTS

In the Jinlida group, HbA1c was significantly reduced (P < 0.05). Greater reductions were observed in patients with baseline HbA1c >8.5%, in males and in those aged >60 years, with a BMI ≤24 kg/m² , or with a duration of T2DM diagnosis >5 years (P < 0.05). Compared with baseline, Jinlida significantly alleviated insulin resistance (P < 0.05) in patients with baseline insulin levels >20 mU/L. Jinlida also significantly improved β-cell function in patients with baseline insulin levels ≤20 mU/L (P < 0.05).

CONCLUSIONS

Jinlida significantly improved glycemic control, with greater improvements in patients with poor glycemic control and male, elderly, of normal weight, or with a long disease course. Furthermore, Jinlida alleviated insulin resistance with hyperinsulinemia and promoted insulin secretion with hypoinsulinemia. These results need to be further confirmed in clinical trials.

Bimagrumab improves body composition and insulin sensitivity in insulin-resistant individuals

AIM

To test the hypothesis that an improving body composition in insulin-resistant individuals could enhance insulin sensitivity.

METHODS

A total of 16 people with a mean body mass index of 29.3 kg/m² and insulin resistance, received a single dose of bimagrumab or placebo and were assessed at week 10 for insulin sensitivity, using a hyperinsulinaemic-euglycaemic clamp and an intravenous glucose tolerance test (IVGTT), and for body composition using dual energy X-ray absorptiometry and positron-emission tomography.

RESULTS

Bimagrumab increased lean mass by 2.7% (P < .05) and reduced fat mass by 7.9% (P = .011) at week 10 compared with placebo, and had a neutral effect on body weight. Bimagrumab reduced glycated haemoglobin by 0.21% at week 18 (P < .001) and improved insulin sensitivity by ~20% (according to the clamp) to ~40% (according to the IVGTT).

CONCLUSION

Taking the observed changes together, and given that these occurred without accompanying dietary intervention and without any prescribed regular physical exercise, bimagrumab may offer a novel approach for the treatment of the metabolic complications of obesity.

Identification of Components in Frog Skin Secretions with Therapeutic Potential as Antidiabetic Agents

Several peptides that were first identified on the basis of their antimicrobial or immunomodulatory properties have subsequently shown potential for development into agents for the treatment of patients with Type 2 diabetes. A strategy is presented for the isolation and characterization of such peptides in norepinephrine-stimulated skin secretions from a range of frog species. The methodology involves fractionation of the secretions by reversed-phase HPLC, identification of fractions containing components that stimulate the rate of release of insulin from BRIN-BD11 clonal β-cells without simultaneously stimulating the release of lactate dehydrogenase, identification of active peptides in the mass range 1-6 kDa by MALDI-TOF mass spectrometry, purification of the peptides to near homogeneity by further HPLC, and structural characterization by automated Edman degradation. The effect of synthetic replicates of the active peptides on glucose homeostasis in vivo may be evaluated in mice fed a high fat diet to produce obesity, glucose intolerance, and insulin resistance.

Increased platelet activation in young Zucker rats with impaired glucose tolerance is improved by acarbose

Patients with diabetes display increased platelet activation. Recent data show a markedly increased risk for cardiovascular events already in pre-diabetic individuals with impaired glucose tolerance (IGT). We investigated whether IGT is associated with platelet activation. Blood samples were collected from young lean (control) and obese Zucker rats, an established model of IGT, after single oral application of sucrose (4g·kg-1). Platelet-bound fibrinogen and platelet surface-expression of P-selectin were assessed as indices of platelet activation using flow cytometry. In lean Zucker rats, acute sucrose application induced fibrinogen-binding and P-selectin surface-expression, which was prevented by co-administration of acarbose (10mg·kg-1). In obese Zucker rats, platelet activation was already maximally increased under baseline conditions with no significant increase after sucrose application. Chronic treatment with acarbose (15mg·kg-1·day-1) significantly reduced platelet activation in these animals. Acute ingestion of sucrose induces platelet activation which is prevented by acarbose. IGT is associated with marked platelet activation that can be reduced by chronic administration of acarbose.The positive modulation of platelet activation by acarbose may contribute to the reduction of cardiovascular events in patients with IGT.

DPP4 INHIBITOR SITAGLIPTIN AS A POTENTIAL TREATMENT OPTION IN METFORMIN-INTOLERANT OBESE WOMEN WITH POLYCYSTIC OVARY SYNDROME: A PILOT RANDOMIZED STUDY

OBJECTIVE

Metformin has an established role in the management of polycystic ovary syndrome (PCOS). Some patients cannot tolerate it due to associated gastrointestinal adverse events. The present study evaluated the dipeptidyl peptidase 4 inhibitor sitagliptin as a potential treatment option in metformin-intolerant PCOS.

METHODS

We conducted a 12-week, prospective, randomized, open-label study with 30 obese metformin-intolerant women with PCOS (age 35.0 ± 7.2 years; body mass index, 36.9 ± 5.5 kg/m²). After metformin withdrawal, they were randomized to lifestyle intervention and sitagliptin 100 mg daily (SITA) or lifestyle intervention alone as controls (CON). All participants underwent anthropometric and endocrine measurements and oral glucose tolerance testing. Model-derived indexes of insulin resistance and beta-cell function were calculated.

RESULTS

SITA improved beta-cell function as assessed by the homeostasis model assessment for beta-cell function index (HOMA-B) of 45.9 ± 35.8 ( P = .001), modified beta-cell function index (MBCI) of 7.9 ± 7 ( P = .002), and quantitative insulin-sensitivity check index (QUICKI) of -0.03 ± 0.03 ( P = .002). By contrast, beta-cell function decreased in CON. The between-group differences were significant for HOMA-B ( P = 0.001), MBCI ( P = .010), and QUICKI ( P = .025). The conversion rate to impaired glucose homeostasis was prevented in SITA: 3 of 15 subjects had impaired glucose tolerance (IGT) before and after the study. In CON, none had type 2 diabetes (T2D), and 4 had IGT at the beginning. After 12 weeks, IGT was observed in 2 and T2D in 3 subjects.

CONCLUSION

SITA improved beta-cell function and prevented a conversion to IGT and T2D in metformin-intolerant obese PCOS patients.

ABBREVIATIONS

BMI = body mass index; DPP-4 = dipeptidyl peptidase-4; DXA = dual energy X-ray absorptiometry; GIP = glucose-dependent insulinotropic peptide; GLP-1 = glucagon-like peptide-1; HOMA-B = homeostasis model assessment for beta-cell function; HOMA-IR = homeostasis model assessment of insulin resistance; IAI = insulin action index; IGT = impaired glucose tolerance; IR = insulin resistance; MBCI = modified beta-cell function index; OGTT = oral glucose tolerance test; QUICKI = quantitative insulin sensitivity check index; PCOS = polycystic ovary syndrome; SHBG = sex hormone-binding globulin; T2D = type 2 diabetes.

Effects of acarbose on cardiovascular and diabetes outcomes in patients with coronary heart disease and impaired glucose tolerance (ACE): a randomised, double-blind, placebo-controlled trial

BACKGROUND

The effect of the α-glucosidase inhibitor acarbose on cardiovascular outcomes in patients with coronary heart disease and impaired glucose tolerance is unknown. We aimed to assess whether acarbose could reduce the frequency of cardiovascular events in Chinese patients with established coronary heart disease and impaired glucose tolerance, and whether the incidence of type 2 diabetes could be reduced.

METHODS

The Acarbose Cardiovascular Evaluation (ACE) trial was a randomised, double-blind, placebo-controlled, phase 4 trial, with patients recruited from 176 hospital outpatient clinics in China. Chinese patients with coronary heart disease and impaired glucose tolerance were randomly assigned (1:1), in blocks by site, by a centralised computer system to receive oral acarbose (50 mg three times a day) or matched placebo, which was added to standardised cardiovascular secondary prevention therapy. All study staff and patients were masked to treatment group allocation. The primary outcome was a five-point composite of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, hospital admission for unstable angina, and hospital admission for heart failure, analysed in the intention-to-treat population (all participants randomly assigned to treatment who provided written informed consent). The secondary outcomes were a three-point composite outcome (cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke), death from any cause, cardiovascular death, fatal or non-fatal myocardial infarction, fatal or non-fatal stroke, hospital admission for unstable angina, hospital admission for heart failure, development of diabetes, and development of impaired renal function. The safety population comprised all patients who received at least one dose of study medication. This trial is registered with ClinicalTrials.gov, number NCT00829660, and the International Standard Randomised Controlled Trial Number registry, number ISRCTN91899513.

FINDINGS

Between March 20, 2009, and Oct 23, 2015, 6522 patients were randomly assigned and included in the intention-to-treat population, 3272 assigned to acarbose and 3250 to placebo. Patients were followed up for a median of 5·0 years (IQR 3·4-6·0) in both groups. The primary five-point composite outcome occurred in 470 (14%; 3·33 per 100 person-years) of 3272 acarbose group participants and in 479 (15%; 3·41 per 100 person-years) of 3250 placebo group participants (hazard ratio 0·98; 95% CI 0·86-1·11, p=0·73). No significant differences were seen between treatment groups for the secondary three-point composite outcome, death from any cause, cardiovascular death, fatal or non-fatal myocardial infarction, fatal or non-fatal stroke, hospital admission for unstable angina, hospital admission for heart failure, or impaired renal function. Diabetes developed less frequently in the acarbose group (436 [13%] of 3272; 3·17 per 100 person-years) compared with the placebo group (513 [16%] of 3250; 3·84 per 100 person-years; rate ratio 0·82, 95% CI 0·71-0·94, p=0·005). Gastrointestinal disorders were the most common adverse event associated with drug discontinuation or dose changes (215 [7%] of 3263 patients in the acarbose group vs 150 [5%] of 3241 in the placebo group [p=0·0007]; safety population). Numbers of non-cardiovascular deaths (71 [2%] of 3272 vs 56 [2%] of 3250, p=0·19) and cancer deaths (ten [<1%] of 3272 vs 12 [<1%] of 3250, p=0·08) did not differ between groups.

INTERPRETATION

In Chinese patients with coronary heart disease and impaired glucose tolerance, acarbose did not reduce the risk of major adverse cardiovascular events, but did reduce the incidence of diabetes.

FUNDING

Bayer AG.

Oral anti-diabetic agents for women with established diabetes/impaired glucose tolerance or previous gestational diabetes planning pregnancy, or pregnant women with pre-existing diabetes

BACKGROUND

While most guidance recommends the use of insulin in women whose pregnancies are affected by pre-existing diabetes, oral anti-diabetic agents may be more acceptable to women. The effects of these oral anti-diabetic agents on maternal and infant health outcomes need to be established in pregnant women with pre-existing diabetes or impaired glucose tolerance, as well as in women with previous gestational diabetes mellitus preconceptionally or during a subsequent pregnancy. This review is an update of a review that was first published in 2010.

OBJECTIVES

To investigate the effects of oral anti-diabetic agents in women with established diabetes, impaired glucose tolerance or previous gestational diabetes who are planning a pregnancy, or pregnant women with pre-existing diabetes, on maternal and infant health. The use of oral anti-diabetic agents for the management of gestational diabetes in a current pregnancy is evaluated in a separate Cochrane Review.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 October 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs assessing the effects of oral anti-diabetic agents in women with established diabetes, impaired glucose tolerance or previous gestational diabetes who were planning a pregnancy, or pregnant women with pre-existing diabetes. Cluster-RCTs were eligible for inclusion, but none were identified.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data and assessed the risk of bias of the included RCTs. Review authors checked the data for accuracy, and assessed the quality of the evidence using the GRADE approach.

MAIN RESULTS

We identified six RCTs (707 women), eligible for inclusion in this updated review, however, three RCTs had mixed populations (that is, they included pregnant women with gestational diabetes) and did not report data separately for the relevant subset of women for this review. Therefore we have only included outcome data from three RCTs; data were available for 241 women and their infants. The three RCTs all compared an oral anti-diabetic agent (metformin) with insulin. The women in the RCTs that contributed data had type 2 diabetes diagnosed before or during their pregnancy. Overall, the RCTs were judged to be at varying risk of bias. We assessed the quality of the evidence for selected important outcomes using GRADE; the evidence was low- or very low-quality, due to downgrading because of design limitations (risk of bias) and imprecise effect estimates (for many outcomes only one or two RCTs contributed data).For our primary outcomes there was no clear difference between metformin and insulin groups for pre-eclampsia (risk ratio (RR) 0.63, 95% confidence interval (CI) 0.33 to 1.20; RCTs = 2; participants = 227; very low-quality evidence) although in one RCT women receiving metformin were less likely to have pregnancy-induced hypertension (RR 0.58, 95% CI 0.37 to 0.91; RCTs = 1; participants = 206; low-quality evidence). Women receiving metformin were less likely to have a caesarean section compared with those receiving insulin (RR 0.73, 95% CI 0.61 to 0.88; RCTs = 3; participants = 241; low-quality evidence). In one RCT there was no clear difference between groups for large-for-gestational-age infants (RR 1.12, 95% CI 0.73 to 1.72; RCTs = 1; participants = 206; very low-quality evidence). There were no perinatal deaths in two RCTs (very low-quality evidence). Neonatal mortality or morbidity composite outcome and childhood/adulthood neurosensory disability were not reported.For other secondary outcomes we assessed using GRADE, there were no clear differences between metformin and insulin groups for induction of labour (RR 1.42, 95% CI 0.62 to 3.28; RCTs = 2; participants = 35; very low-quality evidence), though infant hypoglycaemia was reduced in the metformin group (RR 0.34, 95% CI 0.18 to 0.62; RCTs = 3; infants = 241; very low-quality evidence). Perineal trauma, maternal postnatal depression and postnatal weight retention, and childhood/adulthood adiposity and diabetes were not reported.

AUTHORS' CONCLUSIONS

There are insufficient RCT data to evaluate the use of oral anti-diabetic agents in women with established diabetes, impaired glucose tolerance or previous gestational diabetes who are planning a pregnancy, or in pregnant women with pre-existing diabetes. Low to very low-quality evidence suggests possible reductions in pregnancy-induced hypertension, caesarean section birth and neonatal hypoglycaemia with metformin compared with insulin for women with type 2 diabetes diagnosed before or during their pregnancy, and no clear differences in pre-eclampsia, induction of labour and babies that are large-for-gestational age. Further high-quality RCTs that compare any combination of oral anti-diabetic agent, insulin and dietary and lifestyle advice for these women are needed. Future RCTs could be powered to evaluate effects on short- and long-term clinical outcomes; such RCTs could attempt to collect and report on the standard outcomes suggested in this review. We have identified three ongoing studies and four are awaiting classification. We will consider these when this review is updated.

Genistein prevention of hyperglycemia and improvement of glucose tolerance in adult non-obese diabetic mice are associated with alterations of gut microbiome and immune homeostasis

Although studies have linked soy phytoestrogen 4,7,4-trihydroxyisoflavone genistein (GEN) to reduced type 1 diabetes (T1D) risk, the mechanism of dietary GEN on T1D remains unknown. In our studies, adult non-obese diabetic (NOD) mouse model was employed to investigate the effects of GEN exposure on blood glucose level (BGL), glucose tolerance, gut microbiome, and immune responses. Adult male and female NOD mice were fed with either soy-based or casein-based diet, and received GEN at 20mg/kg body weight by gavage daily. The BGL and immune responses (represented by serum antibodies, cytokines and chemokines, and histopathology) were monitored, while the fecal gut microbiome was sequenced for 16S ribosomal RNA to reveal any alterations in gut microbial communities. A significantly reduced BGL was found in NOD males fed with soy-based diet on day 98 after initial dosing, and an improved glucose tolerance was observed on both diets. In addition, an anti-inflammatory response (suggested by reduced IgG2b and cytokine/chemokine levels, and alterations in the microbial taxonomy) was accompanied by an altered β-diversity in gut microbial species. Among the NOD females exposed to GEN, a later onset of T1D was observed. However, the profiles of gut microbiome, antibodies and cytokines/chemokines were all indicative of pro-inflammation. This study demonstrated an association among GEN exposure, gut microbiome alteration, and immune homeostasis in NOD males. Although the mechanisms underlying the protective effects of GEN in NOD mice need to be explored further, the current study suggested a GEN-induced sex-specific effect in inflammatory status and gut microbiome.