Effect of Liraglutide Treatment on Prediabetes and Overweight or Obesity in Clozapine- or Olanzapine-Treated Patients With Schizophrenia Spectrum Disorder: A Randomized Clinical Trial

Importance

Compared with the general population, patients with schizophrenia have a 2- to 3-fold higher mortality rate primarily caused by cardiovascular disease. Previous interventions designed to counteract antipsychotic-induced weight gain and cardiometabolic disturbances reported limited effects.

Objectives

To determine the effects of the glucagon-like peptide-1 receptor agonist liraglutide added to clozapine or olanzapine treatment of schizophrenia spectrum disorders.

Design, Setting, and Participants

This randomized clinical double-blind trial enrolled participants at 2 clinical sites in Denmark. Of 214 eligible participants with a schizophrenia spectrum disorder, 103 were randomized to liraglutide or placebo. Participants received stable treatment with clozapine or olanzapine, were overweight or obese, and had prediabetes. Data were collected from May 1, 2013, through February 25, 2016.

Interventions

Treatment for 16 weeks with once-daily subcutaneous injection of liraglutide or placebo. Trial drug therapy was titrated during the first 2 weeks of the study.

Main Outcomes and Measures

The primary end point was change in glucose tolerance estimated by a 75-g oral glucose tolerance test result. Secondary end points included change in body weight and cardiometabolic parameters.

Results

Of the 103 patients undergoing randomization (60 men [58.3%] and 43 women [41.7%]), 97 were included in the efficacy analysis, with a mean (SD) age of 42.5 (10.5) years and mean (SD) body mass index (calculated as weight in kilograms divided by height in meters squared) of 33.8 (5.9). The liraglutide and placebo groups had comparable characteristics (mean [SD] age, 42.1 [10.7] vs 43.0 [10.5] years; 30 men in each group; mean [SD] body mass index, 33.7 [5.1] vs 33.9 [6.6]). A total of 96 randomized participants (93.2%) completed the trial. Glucose tolerance improved in the liraglutide group compared with the placebo group (P < .001). Altogether, 30 liraglutide-treated participants (63.8%) developed normal glucose tolerance compared with 8 placebo-treated participants (16.0%) (P < .001; number needed to treat, 2). Body weight decreased with liraglutide compared with placebo (-5.3 kg; 95% CI, -7.0 to -3.7 kg). Reductions in waist circumference (-4.1 cm; 95% CI, -6.0 to -2.3 cm), systolic blood pressure (-4.9 mm Hg; 95% CI, -9.5 to -0.3 mm Hg), visceral fat (-250.19 g; 95% CI, -459.9 to -40.5 g), and low-density lipoprotein levels (-15.4 mg/dL; 95% CI, -23.2 to -7.7 mg/dL) occurred with liraglutide compared with placebo. Adverse events with liraglutide affected mainly the gastrointestinal tract.

Conclusions and Relevance

Liraglutide significantly improved glucose tolerance, body weight, and cardiometabolic disturbances in patients with schizophrenia spectrum disorders treated with clozapine or olanzapine.

Trial Registration

clinicaltrials.gov Identifier: NCT01845259.

Does early-life exposure to organophosphate insecticides lead to prediabetes and obesity?

Human exposures to organophosphate insecticides are ubiquitous. Although regarded as neurotoxicants, increasing evidence points toward lasting metabolic disruption from early-life organophosphate exposures. We gave neonatal rats chlorpyrifos, diazinon or parathion in doses devoid of any acute signs of toxicity, straddling the threshold for barely-detectable cholinesterase inhibition. Organophosphate exposure during a critical developmental window altered the trajectory of hepatic adenylyl cyclase/cyclic AMP signaling, culminating in hyperresponsiveness to gluconeogenic stimuli. Consequently, the animals developed metabolic dysfunction resembling prediabetes. When the organophosphate-exposed animals consumed a high fat diet in adulthood, metabolic defects were exacerbated and animals gained excess weight compared to unexposed rats on the same diet. At the same time, the high fat diet ameliorated many of the central synaptic defects caused by organophosphate exposure, pointing to nonpharmacologic therapeutic interventions to offset neurodevelopmental abnormalities, as well as toward fostering dietary choices favoring high fat intake. These studies show how common insecticides may contribute to the increased worldwide incidence of obesity and diabetes.

Cadmium exposure and risk of diabetes and prediabetes: A systematic review and dose-response meta-analysis

BACKGROUND

Cadmium exposure has been associated with increased diabetes risk in several studies, though there is still considerable debate about the magnitude and shape of the association.

OBJECTIVE

To perform a systematic review and meta-analysis of observational studies investigating the relation between cadmium exposure and risk of type 2 diabetes and prediabetes, and to summarize data on the magnitude and shape of the association.

DATA SOURCE

After conducting an online literature search through October 1, 2021, we identified 42 eligible studies investigating the association between cadmium exposure and risk of diabetes and prediabetes.

STUDY ELIGIBILITY CRITERIA

We included studies that assessed cadmium exposure through biomarker levels; examined type 2 diabetes or prediabetes among outcomes; and reported effect estimates for cadmium exposure for meta-analysis only.

STUDY APPRAISAL AND SYNTHESIS METHODS

Studies were evaluated using ROBINS-E risk of bias tool. We quantitively assessed the relation between exposure and study outcomes using one-stage dose-response meta-analysis with a random effects meta-analytical model.

RESULTS

In the meta-analysis, comparing highest-versus-lowest cadmium exposure levels, summary relative risks (RRs) for type 2 diabetes were 1.24 (95% confidence interval 0.96-1.59), 1.21 (1.00-1.45), and 1.47 (1.01-2.13) for blood, urinary, and toenail matrices, respectively. Similarly, there was an increased risk of prediabetes for cadmium concentrations in both urine (RR = 1.41, 95% CI: 1.15-1.73) and blood (RR = 1.38, 95% CI: 1.16-1.63). In the dose-response meta-analysis, we observed a consistent linear positive association between cadmium exposure and diabetes risk, with RRs of 1.25 (0.90-1.72) at 2.0 µg/g of creatinine. Conversely for blood cadmium, diabetes risk appeared to increase only above 1 µg/L. Prediabetes risk increased up to approximately 2 µg/g creatinine above which it reached a plateau with RR of 1.42 (1.12-1.76) at 2 µg/g creatinine.

LIMITATIONS AND CONCLUSIONS

This analysis provides moderate-certainty evidence for a positive association between cadmium exposure (measured in multiple matrices) and risk of both diabetes and prediabetes.

Alcohol consumption and risk of pre-diabetes and type 2 diabetes development in a Swedish population

AIMS

Alcohol is a potential risk factor of Type 2 diabetes. However, more detailed information on effects of alcohol types and early phases of Type 2 diabetes development seems warranted. The aim of this study was to investigate the influence of alcohol consumption and specific alcoholic beverages on the risk of developing pre-diabetes and Type 2 diabetes in middle-aged Swedish men and women.

METHODS

Subjects, who at baseline had normal glucose tolerance (2070 men and 3058 women) or pre-diabetes (70 men and 41 women), aged 35-56 years, were evaluated in this cohort study. Logistic regression was performed to estimate the risk [odds ratio (OR) and 95% confidence interval (CI)] to develop pre-diabetes and Type 2 diabetes at 8-10 years follow-up, in relation to self-reported alcohol intake at baseline. Adjustment was performed for several risk factors.

RESULTS

Total alcohol consumption and binge drinking increased the risk of pre-diabetes and Type 2 diabetes in men (OR 1.42, 95% CI 1.00-2.03 and OR 1.67, 95% CI 1.11-2.50, respectively), while low consumption decreased diabetes risk in women (OR 0.41, 95% CI 0.22-0.79). Men showed higher risk of pre-diabetes with high beer consumption (OR 1.84, 95% CI 1.13-3.01) and of Type 2 diabetes with high consumption of spirits (OR 2.03, 95% CI 1.27-3.24). Women showed a reduced risk of pre-diabetes with high wine intake (OR 0.66, 95% CI 0.43-0.99) and of Type 2 diabetes with medium intake of both wine and spirits (OR 0.46, 95% CI 0.24-0.88 and OR 0.55, 95% CI 0.31-0.97, respectively), whereas high consumption of spirits increased the pre-diabetes risk(OR 2.41, 95% CI 1.47-3.96).

CONCLUSION

High alcohol consumption increases the risk of abnormal glucose regulation in men. In women the associations are more complex: decreased risk with low or medium intake and increased risk with high alcohol intake.

A word of caution against excessive protein intake

Dietary protein is crucial for human health because it provides essential amino acids for protein synthesis. In addition, dietary protein is more satiating than carbohydrate and fat. Accordingly, many people consider the protein content when purchasing food and beverages and report 'trying to eat more protein'. The global market for protein ingredients is projected to reach approximately US$90 billion by 2021, largely driven by the growing demand for protein-fortified food products. This Perspective serves as a caution against the trend of protein-enriched diets and provides an evidence-based counterpoint that underscores the potential adverse public health consequences of high protein intake.

Cyclosporine A and tacrolimus reduce the amount of GLUT4 at the cell surface in human adipocytes: increased endocytosis as a potential mechanism for the diabetogenic effects of immunosuppressive agents

CONTEXT

Immunosuppressive agents are associated with profound metabolic side effects including new-onset diabetes and dyslipidemia after organ transplantation.

OBJECTIVE

To investigate the effects of cyclosporine A (CsA) and tacrolimus on glucose uptake and insulin signaling in human adipocytes and their impact on the regulation of cellular trafficking of the glucose transporter 4 (GLUT4).

DESIGN

Isolated human adipocytes were incubated with therapeutic concentrations of either CsA or tacrolimus, and glucose uptake and expression of insulin signaling proteins were assessed. Furthermore, we studied effects of CsA and tacrolimus on the regulation of cellular trafficking of GLUT4 in differentiated human preadipocytes and L6 cells.

RESULTS

CsA and tacrolimus had a concentration-dependent inhibitory effect on basal and insulin-stimulated (14)C-glucose uptake in adipocytes. Although phosphorylation at Tyr1146 of the insulin receptor was inhibited by tacrolimus, the phosphorylation and/or protein levels of the insulin signaling proteins IRS1/2, p85-PI3K, PKB, AS160, and mTORC1, as well as GLUT4 and GLUT1, were unchanged by CsA or tacrolimus. Furthermore, CsA and tacrolimus reduced the GLUT4 amount localized at the cell surface of differentiated human preadipocytes and L6 cells in the presence of insulin. This occurred by an increased rate of GLUT4 endocytosis, with no change in the exocytosis rate.

CONCLUSIONS

These results suggest that therapeutic concentrations of CsA and tacrolimus can inhibit glucose uptake independent of insulin signaling by removing GLUT4 from the cell surface via an increased rate of endocytosis. This mechanism can contribute to the development of insulin resistance and diabetes associated with immunosuppressive therapy. In addition, it may provide novel pharmacological approaches for the treatment of diabetes.

Chronic Uridine Administration Induces Fatty Liver and Pre-Diabetic Conditions in Mice

Uridine is a pyrimidine nucleoside that exerts restorative functions in tissues under stress. Short-term co-administration of uridine with multiple unrelated drugs prevents drug-induced liver lipid accumulation. Uridine has the ability to modulate liver metabolism; however, the precise mechanism has not been delineated. In this study, long-term effects of uridine on liver metabolism were examined in both HepG2 cell cultures and C57BL/6J mice. We report that uridine administration was associated with O-GlcNAc modification of FOXO1, increased gluconeogenesis, reduced insulin signaling activity, and reduced expression of a liver-specific fatty acid binding protein FABP1. Long-term uridine feeding induced systemic glucose intolerance and severe liver lipid accumulation in mice. Our findings suggest that the therapeutic potentials of uridine should be designed for short-term acute administration.

Glucose and Lipid Dysmetabolism in a Rat Model of Prediabetes Induced by a High-Sucrose Diet

Glucotoxicity and lipotoxicity are key features of type 2 diabetes mellitus, but their molecular nature during the early stages of the disease remains to be elucidated. We aimed to characterize glucose and lipid metabolism in insulin-target organs (liver, skeletal muscle, and white adipose tissue) in a rat model treated with a high-sucrose (HSu) diet. Two groups of 16-week-old male Wistar rats underwent a 9-week protocol: HSu diet (n = 10)-received 35% of sucrose in drinking water; Control (n = 12)-received vehicle (water). Body weight, food, and beverage consumption were monitored and glucose, insulin, and lipid profiles were measured. Serum and liver triglyceride concentrations, as well as the expression of genes and proteins involved in lipid biosynthesis were assessed. The insulin-stimulated glucose uptake and isoproterenol-stimulated lipolysis were also measured in freshly isolated adipocytes. Even in the absence of obesity, this rat model already presented the main features of prediabetes, with fasting normoglycemia but reduced glucose tolerance, postprandial hyperglycemia, compensatory hyperinsulinemia, as well as decreased insulin sensitivity (resistance) and hypertriglyceridemia. In addition, impaired hepatic function, including altered gluconeogenic and lipogenic pathways, as well as increased expression of acetyl-coenzyme A carboxylase 1 and fatty acid synthase in the liver, were observed, suggesting that liver glucose and lipid dysmetabolism may play a major role at this stage of the disease.

Long-term bisphenol A exposure exacerbates diet-induced prediabetes via TLR4-dependent hypothalamic inflammation

Bisphenol A (BPA), an environmental endocrine-disrupting compound, has been revealed associated with metabolic disorders such as obesity, prediabetes, and type 2 diabetes (T2D). However, its underlying mechanisms are still not fully understood. Here, we provide new evidence that BPA is a risk factor for T2D from a case-control study. To explore the detailed mechanisms, we used two types of diet models, standard diet (SD) and high-fat diet (HFD), to study the effects of long-term BPA exposure on prediabetes in 4-week-old mice. We found that BPA exposure for 12 weeks exacerbated HFD-induced prediabetic symptoms. Female mice showed increased body mass, serum insulin level, and impaired glucose tolerance, while male mice only exhibited impaired glucose tolerance. No change was found in SD-fed mice. Besides, BPA exposure enhanced astrocyte-dependent hypothalamic inflammation in both male and female mice, which impaired proopiomelanocortin (POMC) neuron functions. Moreover, eliminating inflammation by toll-like receptor 4 (TLR4) knockout significantly abolished the effects of BPA on the hypothalamus and diet-induced prediabetes. Taken together, our data establish a key role for TLR4-dependent hypothalamic inflammation in regulating the effects of BPA on prediabetes.

Effects of very mild versus overt diabetes on vascular haemodynamics and barrier function in rats

Rats injected i.p. with a single dose of nicotinamide (250 mg/kg) 15 min prior to i.v. injection of streptozotocin (65 mg/kg) develop a very mild form of diabetes characterized by slight elevations of plasma glucose, increased levels of HbA1, and reduced insulin secretion in response to an i.v. glucose tolerance test. These rats gain weight normally and they are not hyperphagic, glycosuric, or polyuric. The effects of this very mild form of diabetes vs overt streptozotocin diabetes of three months duration on regional vascular 131I-albumin clearance, blood flow (assessed by 15 microns 85Sr-microspheres), and renal filtration function were examined in male Sprague-Dawley rats. Plasma glucose levels of rats with mild diabetes were 7.4 +/- 0.9 (mean +/- SD) (mmol/l) vs 6.5 +/- 0.6 for control rats and 31.3 +/- 6.0 for overtly diabetic rats. HbA1 levels were increased 1.4 fold in mildly diabetic and 2.3 fold in overtly diabetic rats. Vascular clearance of 131I-albumin was markedly increased in ocular tissues (anterior uvea, retina, and choroid), sciatic nerve, aorta, new (subcutaneous) granulation tissue, and kidney of both diabetic groups, although increases in overtly diabetic rats exceeded those in the mildly diabetic group (2.2-4.6 times control animals vs 1.6-3.3 times, respectively). Likewise, both overt and very mild diabetes markedly increased glomerular filtration rate (approximately 1.8 times and 1.2 times control animals, respectively), urinary excretion of endogenous albumin (approximately 9 times and 4 times) and IgG (approximately 15 times and 4 times), as well as regional blood flow in the anterior uvea, choroid, and sciatic nerve. Increases in tissue sorbitol levels were much larger in overtly diabetic rats (generally 10-20 times control animals) than in mildly diabetic rats (1.5-3 times controls). myo-Inositol levels were significantly decreased only in lens and sciatic nerve of overtly diabetic rats. These observations indicate that even very mild diabetes is associated with vascular functional changes which develop more slowly than in overtly diabetic rats, but are disproportionately large (in view of the minimal increases in glycaemia and tissue polyol levels) compared to those in overtly diabetic rats.

PPARγ agonists partially restores hyperglycemia induced aggravation of vascular dysfunction to angiotensin II in thoracic aorta isolated from rats with insulin resistance

Altered vascular responses to various vasopressors in animal models of insulin resistance (IR) and diabetes have been well documented. However, the precise mechanisms about vascular responses in IR with or without frank hyperglycemia (prediabetic state) are not available. Moreover, recently the role of peroxisome proliferators activated receptor-gamma (PPAR gamma) has been linked to influence the vascular responses in hypertensive and diabetic state. Hence, the present study was conceived to determine the role of hyperglycemia on angiotensin II (Ang II) mediated vascular responses in the high fat diet (HFD) induced insulin resistance either with mild or frank hyperglycemia [induced by injection of low dose streptozotocin (STZ) to HFD fed rats (HFD+STZ)]. In addition, insulin-sensitizing agent such as rosiglitazone and pioglitazone were also studied on biochemical and vascular responses. Ang II-induced contractions were studied isometrically in thoracic aortic rings isolated from 4 weeks of normal pellet diet (NPD) fed control, HFD and HFD+STZ fed insulin resistant rats. Specific binding of Ang II receptors were carried out using radioligand ([(3)H]-Ang II) binding studies. After 4 weeks of HFD feeding, rats exhibited characteristics features of insulin resistance such as mild hyperglycemia, hyperinsulinemia, hypertriglyceridemia, hypercholesterolemia and hypertension; whereas HFD+STZ treated rats showed all above parameters along with frank hyperglycemia. Maximal contractile response (E(max)) to Ang II is increased in HFD fed rats as compared to control rats. Moreover, E(max) values are further elevated in HFD+STZ group where the frank hyperglycemia was induced by low dose of streptozotocin. Rosiglitazone (5 mg kg(-1), p.o.) and pioglitazone (10 mg kg(-1), p.o.) treatment significantly lowered the plasma glucose, triglycerides, insulin and cholesterol levels in insulin resistance rats. In addition, it also restored the elevated systolic, mean arterial, diastolic blood pressure and attenuated the enhanced contractile responses to Ang II in thoracic aortic rings obtained from both HFD and HFD+STZ treated rats. Specific binding of [(3)H]-Ang II is upregulated in HFD-fed and HFD+STZ treated rats. Treatment with pioglitazone and rosiglitazone significantly decreased the AT(1)R specific binding in HFD fed rats. Our results indicate the role of hyperglycemia in the elevation of Ang II induced vascular responses in thoracic aorta isolated from insulin resistant rats and PPAR gamma agonists can attenuate these responses.

Sensitivity to Thyroid Hormones and Risk of Prediabetes: A Cross-Sectional Study

CONTEXT

Thyroid hormone influences glucose homeostasis through central and peripheral regulations. To date, the link between sensitivity to thyroid hormones and prediabetes remains unknown. We aimed to investigate the association between thyroid hormones sensitivity and risk of prediabetes in both general and euthyroid populations.

METHODS

Participants with serum free triiodothyronine (FT3), free thyroxine (FT4), and thyrotropin (TSH) measurements from the health checkup programs of the First Hospital of China Medical University were collected. We measured the parameters representing central and peripheral sensitivities to thyroid hormones (central sensitivity, assessed by calculating Thyroid Feedback Quantile-based Index (TFQI), TSH Index (TSHI), and Thyrotroph Thyroxine Resistance Index (TT4RI); peripheral sensitivity, evaluated by FT3/FT4 ratio). Associations between thyroid hormones sensitivities and risk of prediabetes were assessed with logistic regression.

RESULTS

A total of 4378 participants (mean age ± SD, 49 ± 11 years) were included, with 1457 (33%) subjects had prediabetes. The risk of prediabetes was negatively associated with levels of TSHI (odds ratio [OR] 0.91; 95% confidence interval [CI], 0.85-0.97), TT4RI (OR 0.91; 95% CI, 0.84-0.99) and Parametric TFQI (PTFQI) (OR 0.89; 95% CI, 0.83-0.95) among all subjects. The association remained significant in euthyroid subjects and euthyroid subjects with negative thyroid autoimmunity. Higher FT3/FT4 ratio was associated with a mild increased risk of prediabetes (95% CI 1.09; 1.02-1.16). Compared with subjects in the lowest quartile of PTFQI, those in the highest quartile had lower risk of prediabetes (0.70; 95% CI, 0.58-0.84).

CONCLUSIONS

Decreased central sensitivity to thyroid hormones is associated with lower risk of prediabetes. This demonstrates the complex interaction between thyroid system and glucose metabolism. Future studies are warranted to confirm our findings and underlying mechanisms.

White tea intake prevents prediabetes-induced metabolic dysfunctions in testis and epididymis preserving sperm quality

Prediabetes has been associated with alterations in male reproductive tract, especially in testis and epididymis. Moreover, in vitro studies described a promising action of tea (Camellia sinensis L.) against metabolic dysfunctions. Herein, we hypothesized that white tea (WTEA) ingestion by prediabetic animals could ameliorate the metabolic alterations induced by the disease in testicular and epididymal tissues, preserving sperm quality. WTEA infusion was prepared and its phytochemical profile was evaluated by ¹H-NMR. A streptozotocin-induced prediabetic rat model was developed and three experimental groups were defined: control, prediabetic (PreDM) and prediabetic drinking WTEA (PreDM+WTEA). Metabolic profiles of testis and epididymis were evaluated by determining the metabolites content (¹H-NMR), protein levels (western blot) and enzymatic activities of key metabolic intervenient. The quality of spermatozoa from cauda epididymis was also assessed. Prediabetes increased glucose transporter 3 protein levels and decreased lactate dehydrogenase activity in testis, resulting in a lower lactate content. WTEA ingestion led to a metabolic adaptation to restore testicular lactate content. Concerning epididymis, prediabetes decreased the protein levels of several metabolic intervenient, resulting in decreased lactate and alanine content. WTEA consumption restored most of the evidenced alterations, however, not lactate content. WTEA also improved epididymal sperm motility and restored sperm viability. Prediabetes strongly affected testicular and epididymal metabolic status and most of these alterations were restored by WTEA consumption, resulting in the improvement of sperm quality. Our results suggest that WTEA consumption can be a cost-effective strategy to improve prediabetes-induced reproductive dysfunction.

Risk factor assessment for new onset diabetes: literature review

Metabolic syndrome (MS), typified by hypertension, abdominal obesity, dyslipidaemia and impaired glucose metabolism, is a precursor of type 2 diabetes. Thiazide diuretics (TD) and beta-blockers are associated with increased risk of diabetes in patients with hypertension; however, the role of these agents in development of diabetes in MS patients is unknown. We reviewed the literature regarding risk factors for diabetes development and compared this with data from the Study of Trandolapril/Verapamil SR And Insulin Resistance (STAR), which investigated the effects of two fixed-dose combinations (FDCs) [trandolapril/verapamil SR and losartan/hydrochlorothiazide (L/H)] on glucose control and new diabetes in MS patients. In STAR, logistic regression modelling identified haemoglobin A1c [odds ratio (OR) 4.21 per 1% increment; p = 0.003), L/H treatment (OR 4.04; p = 0.002) and 2-h oral glucose tolerance test glucose levels (OR 1.39 per 10 mg/dl increments; p < 0.001) as baseline predictors of diabetes. These data support prior analyses and suggest that choice of antihypertensive agent is important. Patients with MS may be at lower risk of diabetes when using a FDC calcium channel blocker + angiotensin-converting enzyme inhibitor compared with an angiotensin receptor blocker + TD.

Statin therapy with or without ezetimibe and the progression to diabetes

OBJECTIVE

To assess the risk of progression from normoglycemia or prediabetes to overt diabetes among individuals treated with statins alone or in combination with ezetimibe.

METHODS

This was a retrospective study conducted in Greece including 877 subjects treated for dyslipidemia. We included individuals without overt diabetes at baseline and divided them in 2 subgroups according to their baseline fasting glucose: <100 (normal glucose) and 100 to 125 mg/dL (prediabetes). High and moderate-intensity statin therapy was defined according to the expected low-density lipoprotein cholesterol reduction (≥50% and 30 to <50%, respectively). We identified the predictors of incident diabetes and assessed the risk of new-onset diabetes among subgroups on various intensity statin or no statin treatment at all. Similar analyses were performed across different potency of statin monotherapy or combination of statin plus ezetimibe treatment.

RESULTS

A total of 877 subjects were eligible and followed-up for a median of 7 years. There were no differences between statins regarding diabetes development. However, a higher risk of incident diabetes was observed in prediabetic individuals receiving high-intensity statin therapy compared with those on moderate intensity (adjusted odds ratio [OR] = 2.12, 95% confidence interval [CI] = 1.06-4.24, P < .05) and those not taking a statin (adjusted OR = 4.90; 95% CI = 1.16-20.66, P < .05). The addition of ezetimibe to statin treatment did not increase the risk of incident diabetes in prediabetic individuals (adjusted OR = 0.89; 95% CI = 0.36-2.22, P > .05). Baseline fasting glucose, presence of metabolic syndrome, family history of diabetes, and follow-up duration were independent predictors of new-onset diabetes.

CONCLUSION

High-intensity statin treatment is associated with a higher risk of incident diabetes in prediabetic individuals, whereas the addition of ezetimibe to statin therapy has a neutral effect on glucose metabolism.

Anti-diabetic effects of Sutherlandia frutescens in Wistar rats fed a diabetogenic diet

Sutherlandia frutescens has been marked as a potential hypoglycaemic agent for the treatment of type 2 diabetes. We investigated the effects of Sutherlandia frutescens in bringing about hypoglycaemia and promoting glucose uptake in pre-diabetic rats. Crushed Sutherlandia frutescens leaves in drinking water were administered to rats fed a high fat diet. Positive control rats received only metformin. Glucose uptake experiments were undertaken using [(3)H] deoxy-glucose. Various physiological parameters were also measured. Rats receiving Sutherlandia frutescens displayed normoinsulinaemic levels, after 8 weeks medicational compliance, compared to the fatty controls. There was a significant increase in glucose uptake into muscle and adipose tissue, and a significant decrease in intestinal glucose uptake (p<0.001 at 60min) in rats receiving the plant extract. The Sutherlandia frutescens plant extract shows promise as a type 2 anti-diabetes medication because of its ability to normalize insulin levels and glucose uptake in peripheral tissues and suppress intestinal glucose uptake, with no weight gain noted. The exact mechanism of action and the extract's efficacy in humans need further confirmation.

In search of moderators and mediators of hyperglycemia with atypical antipsychotic treatment

Signal detection methods were used to identify values of metabolic variables that predict development of prediabetes or diabetes before (moderators) or associated with treatment (mediators), utilizing data from two multi-center clinical trials of patients with schizophrenia, treated for 6 months with olanzapine (OLZ) or ziprasidone (ZIP). At baseline, participants were often overweight/obese (63% with a body mass index >or=25.0kg/m(2)), dyslipidemic [more than one-third had elevated triglyceride (TG) and low high-density lipoprotein cholesterol (HDL-C) concentrations], and prediabetic (20%). Weight gain was significantly greater in OLZ-treated patients, as was accentuation of dyslipidemia. However, there were no significant correlations between weight gain and lipid changes from baseline to weeks 2, 4, 8 or to last observation. Type 2 diabetes developed in 4% and prediabetes in 18% of the population. Significant baseline predictors of diabetes were a HDL-C concentration <28mg/dL, or being >or=58-years-old if HDL-C concentration was >or=28mg/dL. Baseline plasma glucose concentration >or=92mg/dL was the only significant predictor of developing prediabetes, accounting for 60% of cases. Post-treatment increments in plasma TG concentrations >or=145mg/dL or >or=59mg/dL were significant predictors of diabetes (23%) or prediabetes (27%), respectively. If the increase in TG was <145mg/dL, rapid weight gain >or=6.1kg in 2 weeks predicted development of diabetes (18%). These findings provide a quantitative approach to identify those at greatest treatment-associated risk to develop glucose intolerance, and emphasize the need to address co-morbid medical disorders in these patients.

Consensus on the Statin of Choice in Patients with Impaired Glucose Metabolism: Results of the DIANA Study

Introduction and Objectives

Despite the recognized clinical benefit of statins on cardiovascular prevention, providing correct management of hypercholesterolaemia, possible adverse effects of their use cannot be disregarded. Previously published data shows that there is a risk of developing diabetes mellitus or experiencing changes in glucose metabolism in statin-treated patients. The possible determining factors are the drug characteristics (potency, dose), patient characteristics (kidney function, age, cardiovascular risk and polypharmacy because of multiple disorders) and the pre-diabetic state.

Methods

In order to ascertain the opinion of the experts (primary care physicians and other specialists with experience in the management of this type of patient) we conducted a Delphi study to evaluate the consensus rate on diverse aspects related to the diabetogenicity of different statins, and the factors that influence their choice.

Results

Consensus was highly significant concerning aspects such as the varying diabetogenicity profiles of different statins, as some of them do not significantly worsen glucose metabolism. There was an almost unanimous consensus that pitavastatin is the safest statin in this regard.

Conclusions

Factors to consider in the choice of a statin regarding its diabetogenicity are the dose and patient-related factors: age, cardiovascular risk, diabetes risk and baseline metabolic parameters (which must be monitored during the treatment), as well as kidney function.

Ameliorative effect of nicotine exposure on insulin resistance is accompanied by decreased cardiac glycogen synthase kinase-3 and plasminogen activator inhibitor-1 during oral oestrogen-progestin therapy

CONTEXT

Cigarette smoking is considered to be a major risk factor for the development of diabetes and cardiovascular disease. Oestrogen-progestin combined oral contraceptive (COC) use has been associated with adverse cardiometabolic events.

OBJECTIVE

We hypothesized that nicotine would ameliorate insulin resistance (IR) that is accompanied by decreased cardiac glycogen synthase kinase-3 (GSK-3) and plasminogen activator inhibitor-1 (PAI-1).

METHODS

Female Wistar rats received (po) low-(0.1 mg/kg) or high-nicotine (1.0 mg/kg) with or without COC containing 5.0 µg levonorgestrel plus 1.0 µg ethinylestradiol daily for 8 weeks.

RESULTS

Data showed that COC treatment or nicotine exposure led to IR, glucose deregulation, atherogenic dyslipidemia, increased corticosterone, aldosterone, cardiac and circulating GSK-3 values and PAI-1. However, these effects with the exception of corticosterone and aldosterone were ameliorated in COC + nicotine-exposed rats.

CONCLUSION

Amelioration of IR induced by COC treatment is accompanied by decreased circulating PAI-1, cardiac PAI-1 and GSK-3 instead of circulating aldosterone and corticosterone.

Effects of a Ruthenium Schiff Base Complex on Glucose Homeostasis in Diet-Induced Pre-Diabetic Rats

Pre-diabetes is a condition that precedes type 2 diabetes mellitus (T2DM) that is characterised by elevated glycated haemoglobin (HbA1c). The management of pre-diabetes includes the combination of dietary and pharmacological interventions to increase insulin sensitivity. However, poor patient compliance has been reported with regard to dietary interventions, therefore, new alternative drugs are required that can be effective even without the dietary intervention. In our laboratory, we have synthesised a novel ruthenium complex that has been shown to have elevated biological activity. This study investigated the effects of this complex in both the presence and absence of dietary intervention on glucose handling in a diet-induced pre-diabetes rat model. Pre-diabetic animals were randomly assigned to respective treatment groups. The ruthenium complex was administered to pre-diabetic rats once a day every third day for 12 weeks. The administration of the ruthenium complex resulted in reduced fasting blood glucose, food intake, and body weight gain which was associated with decreased plasma ghrelin, insulin, and HbA1c levels in both the presence and absence of dietary intervention. The administration of the ruthenium complex ameliorated glycaemic control and insulin sensitivity in pre-diabetic rats. The results of this study warrant further investigations as this compound could potentially be able to re-sensitize insulin resistant cells and reduce the incidence of T2DM.

Chicken embryos as a potential new model for early onset type I diabetes

Diabetic retinopathy (DR) is the leading cause of blindness among the American working population. The purpose of this study is to establish a new diabetic animal model using a cone-dominant avian species to address the distorted color vision and altered cone pathway responses in prediabetic and early diabetic patients. Chicken embryos were injected with either streptozotocin (STZ), high concentration of glucose (high-glucose), or vehicle at embryonic day 11. Cataracts occurred in varying degrees in both STZ- and high glucose-induced diabetic chick embryos at E18. Streptozotocin-diabetic chicken embryos had decreased levels of blood insulin, glucose transporter 4 (Glut4), and phosphorylated protein kinase B (pAKT). In STZ-injected E20 embryos, the ERG amplitudes of both a- and b-waves were significantly decreased, the implicit time of the a-wave was delayed, while that of the b-wave was significantly increased. Photoreceptors cultured from STZ-injected E18 embryos had a significant decrease in L-type voltage-gated calcium channel (L-VGCC) currents, which was reflected in the decreased level of L-VGCCα1D subunit in the STZ-diabetic retinas. Through these independent lines of evidence, STZ-injection was able to induce pathological conditions in the chicken embryonic retina, and it is promising to use chickens as a potential new animal model for type I diabetes.

IL-33 Prevents MLD-STZ Induction of Diabetes and Attenuate Insulitis in Prediabetic NOD Mice

Type 1 diabetes is an autoimmune disease caused by the immune-mediated destruction of pancreatic β-cells. Prevention of type 1 diabetes requires early intervention in the autoimmune process against beta-cells of the pancreatic islets of Langerhans, which is believed to result from disordered immunoregulation. CD4+Foxp3+ regulatory T cells (Tregs) participate as one of the most important cell types in limiting the autoimmune process. The aim of this study was to investigate the effect of exogenous IL-33 in multiple low dose streptozotocin (MLD-STZ) induced diabetes and to delineate its role in the induction of protective Tregs in an autoimmune attack. C57BL/6 mice were treated i. p. with five doses of 40 mg/kg STZ and 0.4 μg rIL-33 four times, starting from day 0, 6, or 12 every second day from the day of disease induction. 16 weeks old NOD mice were treated with 6 injections of 0.4 μg/mouse IL-33 (every second day). Glycemia and glycosuria were measured and histological parameters in pancreatic islets were evaluated at the end of experiments. Cellular make up of the pancreatic lymph nodes and islets were evaluated by flow cytometry. IL-33 given simultaneously with the application of STZ completely prevented the development of hyperglycemia, glycosuria and profoundly attenuated mononuclear cell infiltration. IL-33 treatment was accompanied by higher number of IL-13 and IL-5 producing CD4+ T cells and increased presence of ST2+Foxp3+ regulatory T cells in pancreatic lymph nodes and islets. Elimination of Tregs abrogated protective effect of IL-33. We provide evidence that exogenous IL-33 completely prevents the development of T cell mediated inflammation in pancreatic islets and consecutive development of diabetes in C57BL/6 mice by facilitating the induction Treg cells. To extend this finding for possible relevance in spontaneous diabetes, we showed that IL-33 attenuate insulitis in prediabetic NOD mice.

Association of long-term air pollution exposure with the risk of prediabetes and diabetes: Systematic perspective from inflammatory mechanisms, glucose homeostasis pathway to preventive strategies

BACKGROUND

Limited evidence suggests the association of air pollutants with a series of diabetic cascades including inflammatory pathways, glucose homeostasis disorder, and prediabetes and diabetes. Subclinical strategies for preventing such pollutants-induced effects remain unknown.

METHODS

We conducted a cross-sectional study in two typically air-polluted Chinese cities in 2018-2020. One-year average PM₁, PM_2.5, PM₁₀, SO₂, NO₂, and O₃ were calculated according to participants' residence. GAM multinomial logistic regression was performed to investigate the association of air pollutants with diabetes status. GAM and quantile g-computation were respectively performed to investigate individual and joint effects of air pollutants on glucose homeostasis markers (glucose, insulin, HbA1c, HOMA-IR, HOMA-B and HOMA-S). Complement C3 and hsCRP were analyzed as potential mediators. The ABCS criteria and hemoglobin glycation index (HGI) were examined for their potential in preventive strategy.

RESULTS

Long-term air pollutants exposure was associated with the risk of prediabetes [Prevalence ratio for O₃ (PR_O₃) = 1.96 (95% CI: 1.24, 3.03)] and diabetes [PR_PM₁ = 1.18 (95% CI: 1.05, 1.32); PR_PM_2.5 = 1.08 (95% CI: 1.00, 1.16); PR_O₃ = 1.35 (95% CI: 1.03, 1.74)]. PM₁, PM₁₀, SO₂ or O₃ exposure was associated with glucose-homeostasis disorder. For example, O₃ exposure was associated with increased levels of glucose [7.67% (95% CI: 1.75, 13.92)], insulin [19.98% (95% CI: 4.53, 37.72)], HOMA-IR [34.88% (95% CI: 13.81, 59.84)], and decreased levels of HOMA-S [-25.88% (95% CI: -37.46, -12.16)]. Complement C3 and hsCRP played mediating roles in these relationships with proportion mediated ranging from 6.95% to 60.64%. Participants with HGI ≤ -0.53 were protected from the adverse effects of air pollutants.

CONCLUSION

Our study provides comprehensive insights into air pollutant-associated diabetic cascade and suggests subclinical preventive strategies.

Proinflammatory lipid signals trigger the health effects of air pollution in individuals with prediabetes

Individuals with metabolic disorders exhibit enhanced susceptibility to the cardiovascular health effects of particulate air pollution, but the underlying mechanisms are not yet understood. We aim to assess whether changes in proinflammatory lipid signals are associated with fine particulate matter (PM_2.5) exposure in individuals with and without prediabetes. A longitudinal panel study was conducted in Beijing, China, and included 120 participants followed up over 589 clinical visits from August 2013 to February 2015. We measured 12 lipids derived from arachidonic acid pathways in blood samples of the participants via targeted lipidomic analyses. Ambient PM_2.5 concentrations were continuously monitored at a station for associations with the lipids. Among the 120 participants, 110 (mean [SD] age at recruitment, 56.5 [4.2] years; 31 prediabetics) who visited the clinic at least twice over the follow-up period were assigned exposure values of the outdoor residential PM_2.5 concentrations during the 1-14 days preceding each clinical visit. With an interquartile range increase in the 1-day-lag PM_2.5 exposure (64.0 μg/m³), the prediabetic group had consistently greater increases in the concentration of arachidonate metabolites derived from the cytochrome P450 (CYP450) pathway (5,6-DHET, 15.8% [95% CI, 3.5-29.7%]; 8,9-DHET, 9.7% [95% CI, 0.6-19.6%]; 11,12-DHET, 8.3% [95% CI, 1.9-15.1%]; 14,15-DHET, 7.4% [95% CI, 0.9-14.4%]; and 20-HETE, 8.9% [95% CI, 1.0-17.5%]), compared with the healthy group. Among CYP450-derived lipids, 14,15-DHET and 20-HETE significantly mediated 8% and 8% of the PM_2.5-associated increase in white blood cells, 10% and 13% of that in neutrophils, and 20% and 23% of that in monocytes, respectively, in the prediabetic group. In conclusion, proinflammatory lipid signals from CYP450 pathways triggered the health effects of particulate air pollution in individuals with prediabetes, suggesting that targeting lipid metabolism has therapeutic potential to attenuate or prevent the cardiovascular effects of air pollution in susceptible populations.