Thiazolidinedione therapy in the prevention/delay of type 2 diabetes in patients with impaired glucose tolerance and insulin resistance

The role of PPARγ in prostate cancer development and progression

Advanced and metastatic prostate cancer is often incurable, but its dependency on certain molecular alterations may provide the basis for targeted therapies. A growing body of research has demonstrated that peroxisome proliferator-activated receptor gamma (PPARγ) is amplified as prostate cancer progresses. PPARγ has been shown to support prostate cancer growth through its roles in fatty acid synthesis, mitochondrial biogenesis, and co-operating with androgen receptor signalling. Interestingly, splice variants of PPARγ may have differing and contrasting roles. PPARγ itself is a highly druggable target, with agonists having been used for the past two decades in treating diabetes. However, side effects associated with these compounds have currently limited clinical use of these drugs in prostate cancer. Further understanding of PPARγ and novel techniques to target it, may provide therapies for advanced prostate cancer.

HM-Chromanone Ameliorates Hyperglycemia and Dyslipidemia in Type 2 Diabetic Mice

The effects of (E)-5-hydroxy-7-methoxy-3-(2-hydroxybenzyl)-4-chromanone (HMC) on hyperglycemia and dyslipidemia were investigated in diabetic mice. Mice were separated into three groups: db/db, rosiglitazone and HMC. Blood glucose or glycosylated hemoglobin values in HMC-treated mice were significantly lower compared to db/db mice. Total cholesterol, LDL-cholesterol, and triglyceride values were lower, and HDL-C levels were higher, in the HMC group compared to the diabetic and rosiglitazone groups. HMC markedly increased IRS-1^Tyr612, Akt^Ser473 and PI3K levels and plasma membrane GLUT4 levels in skeletal muscle, suggesting improved insulin resistance. HMC also significantly stimulated AMPK^Thr172 and PPARα in the liver, and ameliorated dyslipidemia by inhibiting SREBP-1c and FAS. Consequently, HMC reduced hyperglycemia by improving the expression of insulin-resistance-related genes and improved dyslipidemia by regulating fatty acid synthase and oxidation-related genes in db/db mice. Therefore, HMC could ameliorate hyperglycemia and dyslipidemia in type 2 diabetic mice.

Pioglitazone for prevention or delay of type 2 diabetes mellitus and its associated complications in people at risk for the development of type 2 diabetes mellitus

BACKGROUND

The term prediabetes is used to describe a population with an elevated risk of developing type 2 diabetes mellitus (T2DM). With projections of an increase in the incidence of T2DM, prevention or delay of the disease and its complications is paramount. It is currently unknown whether pioglitazone is beneficial in the treatment of people with increased risk of developing T2DM.

OBJECTIVES

To assess the effects of pioglitazone for prevention or delay of T2DM and its associated complications in people at risk of developing T2DM.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Chinese databases, ICTRP Search Portal and ClinicalTrials.gov. We did not apply any language restrictions. Further, we investigated the reference lists of all included studies and reviews. We tried to contact all study authors. The date of the last search of databases was November 2019 (March 2020 for Chinese databases).

SELECTION CRITERIA

We included randomised controlled trials (RCTs) with a minimum duration of 24 weeks, and participants diagnosed with intermediate hyperglycaemia with no concomitant diseases, comparing pioglitazone as monotherapy or part of dual therapy with other glucose-lowering drugs, behaviour-changing interventions, placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened abstracts, read full-text articles and records, assessed risk of bias and extracted data. We performed meta-analyses with a random-effects model and calculated risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes, with 95% confidence intervals (CIs) for effect estimates. We evaluated the certainty of the evidence with the GRADE.

MAIN RESULTS

We included 27 studies with a total of 4186 randomised participants. The size of individual studies ranged between 43 and 605 participants and the duration varied between 6 and 36 months. We judged none of the included studies as having low risk of bias across all 'Risk of bias' domains. Most studies identified people at increased risk of T2DM by impaired fasting glucose or impaired glucose tolerance (IGT), or both. Our main outcome measures were all-cause mortality, incidence of T2DM, serious adverse events (SAEs), cardiovascular mortality, nonfatal myocardial infarction or stroke (NMI/S), health-related quality of life (QoL) and socioeconomic effects. The following comparisons mostly reported only a fraction of our main outcome set. Three studies compared pioglitazone with metformin. They did not report all-cause and cardiovascular mortality, NMI/S, QoL or socioeconomic effects. Incidence of T2DM was 9/168 participants in the pioglitazone groups versus 9/163 participants in the metformin groups (RR 0.98, 95% CI 0.40 to 2.38; P = 0.96; 3 studies, 331 participants; low-certainty evidence). No SAEs were reported in two studies (201 participants; low-certainty evidence). One study compared pioglitazone with acarbose. Incidence of T2DM was 1/50 participants in the pioglitazone group versus 2/46 participants in the acarbose group (very low-certainty evidence). No participant experienced a SAE (very low-certainty evidence).One study compared pioglitazone with repaglinide. Incidence of T2DM was 2/48 participants in the pioglitazone group versus 1/48 participants in the repaglinide group (low-certainty evidence). No participant experienced a SAE (low-certainty evidence). One study compared pioglitazone with a personalised diet and exercise consultation. All-cause and cardiovascular mortality, NMI/S, QoL or socioeconomic effects were not reported. Incidence of T2DM was 2/48 participants in the pioglitazone group versus 5/48 participants in the diet and exercise consultation group (low-certainty evidence). No participant experienced a SAE (low-certainty evidence). Six studies compared pioglitazone with placebo. No study reported on QoL or socioeconomic effects. All-cause mortality was 5/577 participants the in the pioglitazone groups versus 2/579 participants in the placebo groups (Peto odds ratio 2.38, 95% CI 0.54 to 10.50; P = 0.25; 4 studies, 1156 participants; very low-certainty evidence). Incidence of T2DM was 80/700 participants in the pioglitazone groups versus 131/695 participants in the placebo groups (RR 0.40, 95% CI 0.17 to 0.95; P = 0.04; 6 studies, 1395 participants; low-certainty evidence). There were 3/93 participants with SAEs in the pioglitazone groups versus 1/94 participants in the placebo groups (RR 3.00, 95% CI 0.32 to 28.22; P = 0.34; 2 studies, 187 participants; very low-certainty evidence). However, the largest study for this comparison did not distinguish between serious and non-serious adverse events. This study reported that 121/303 (39.9%) participants in the pioglitazone group versus 151/299 (50.5%) participants in the placebo group experienced an adverse event (P = 0.03). One study observed cardiovascular mortality in 2/181 participants in the pioglitazone group versus 0/186 participants in the placebo group (RR 5.14, 95% CI 0.25 to 106.28; P = 0.29; very low-certainty evidence). One study observed NMI in 2/303 participants in the pioglitazone group versus 1/299 participants in the placebo group (RR 1.97: 95% CI 0.18 to 21.65; P = 0.58; very low-certainty evidence). Twenty-one studies compared pioglitazone with no intervention. No study reported on cardiovascular mortality, NMI/S, QoL or socioeconomic effects. All-cause mortality was 11/441 participants in the pioglitazone groups versus 12/425 participants in the no-intervention groups (RR 0.85, 95% CI 0.38 to 1.91; P = 0.70; 3 studies, 866 participants; very low-certainty evidence). Incidence of T2DM was 60/1034 participants in the pioglitazone groups versus 197/1019 participants in the no-intervention groups (RR 0.31, 95% CI 0.23 to 0.40; P < 0.001; 16 studies, 2053 participants; moderate-certainty evidence). Studies reported SAEs in 16/610 participants in the pioglitazone groups versus 21/601 participants in the no-intervention groups (RR 0.71, 95% CI 0.38 to 1.32; P = 0.28; 7 studies, 1211 participants; low-certainty evidence). We identified two ongoing studies, comparing pioglitazone with placebo and with other glucose-lowering drugs. These studies, with 2694 participants. may contribute evidence to future updates of this review.

AUTHORS' CONCLUSIONS

Pioglitazone reduced or delayed the development of T2DM in people at increased risk of T2DM compared with placebo (low-certainty evidence) and compared with no intervention (moderate-certainty evidence). It is unclear whether the effect of pioglitazone is sustained once discontinued. Pioglitazone compared with metformin neither showed advantage nor disadvantage regarding the development of T2DM in people at increased risk (low-certainty evidence). The data and reporting of all-cause mortality, SAEs, micro- and macrovascular complications were generally sparse. None of the included studies reported on QoL or socioeconomic effects.

Pharmacological Primary Prevention of Diabetes Mellitus Type II: A Narrative Review

The evolving epidemic of type 2 diabetes mellitus has challenged health-care professionals. It stands among the leading causes of mortality in the present world. It warrants new and versatile approaches to improve mortality and the associated huge quality-adjusted life years lost to it once diagnosed. A possible venue to lower the incidence is to assess the safety and efficacy of various diabetes prevention strategies. Diet and exercise have a well-developed role in the prevention of weight gain and, ultimately, diabetes mellitus type II in high-risk individuals. However, high-risk individuals can also benefit from adjunct pharmacotherapy. In light of this information, we decided to conduct a systematic review of randomized controlled trials. This article summarizes the evidence in the literature on the pharmacological prevention of diabetes in high-risk individuals.

Does obesity cause type 2 diabetes mellitus (T2DM)? Or is it the opposite?

Obesity is believed to be a promoter of type 2 diabetes mellitus (T2DM). Reports indicate that severe obesity in childhood and adolescence increases the risk of T2DM in youth and young adults. T2DM, which is commonly asymptomatic, frequently is not recognized until random blood glucose is measured. Screening blood glucose levels measured in obese individuals are more effective for identifying undiagnosed persons, than screening the general population and therefore introduces a selection bias for discovery. The following commentary will indicate why these observations do not indicate that obesity is the cause of T2DM. Also, it will be shown that the insulin resistance of T2DM occurs primarily in the muscles of lean individuals predisposed to diabetes before they become obese. This insulin resistance is not secondary to, but instead, is the cause of the excessive fat accumulation associated with T2DM. Moreover, this early muscle insulin resistance is the etiology of the hyperlipidemia and excess fat accumulation characteristic of T2DM.

Effects of Lifestyle Modification and Anti-diabetic Medicine on Prediabetes Progress: A Systematic Review and Meta-Analysis

Background: Pre-diabetes is a risk factor for full-blown diabetes; it presents opportunities to prevent the actual diseases. It is therefore essential to identify effective preventive strategies, and to clarify the direction of future research. Methods: PubMed, Embase and Cochrane Central Register of Controlled Trials were searched using key terms (Supplementary Table 1). We applied network meta-analysis to multiple comparisons among various diabetic preventive strategies, including lifestyle and pharmacological interventions; traditional meta-analysis for the synthesis of basal metabolic changes after interventions; and trial sequential analysis for determinations as to whether analysis conclusions meet expectations. Results: We included 32 randomized controlled trials comprising 43,669 patients and 14 interventions in the meta-analysis. Both lifestyle modifications and anti-diabetic medications improved physical conditions, including weight loss, blood glucose, and blood pressure. Network meta-analysis suggested that the progression of diabetes could be delayed to varying degrees by lifestyle and pharmacological interventions, except for angiotensin-converting enzyme inhibitors, statins, sulfonylureas and vitamin D. The risk ratios (RR) [95% credible interval (CrI)] compared with control were: GLP-1RAs 0.28 (0.15, 0.50), Orlistat 0.33 (0.18, 0.55), TZM 0.33 (0.16, 0.63), TZD 0.39 (0.27, 0.53), LST 0.54 (0.32, 0.88), lifestyle 0.58 (0.49, 0.67), LSM 0.62 (0.45, 0.80), GI 0.66 (0.46, 0.88), SU 0.67 (0.40, 1.00), Vitamin D 0.91 (0.59, 1.40), ACEI 0.93 (0.62, 1.40), statins 1.20 (0.84, 1.60). Conclusions: In adults with pre-diabetes, firm evidence supports the notion that lifestyle modifications and metformin reduces the incidence of diabetes with an average of 20% relative risk reduction, while statins increase the relative risk 20%. We found that lifestyle modifications, promising long-term strategies involving three factors (nutrition, exercise, and weight loss) contribute to health by reducing BMI, body weight, waist and hip circumference, systolic and diastolic pressure, fasting, and 2-h postprandial blood glucose, total cholesterol and by increasing HDL. We made this determination using TSA, avoiding further waste of experimental resources.

Effectiveness and Safety of Hydroxychloroquine compared to Teneligliptin in uncontrolled T2DM patients as add-on Therapy

Objectives

Hydroxychloroquine (HCQ) 400 mg is approved by the Drug Controller General of India (DCGI) and recommended by the Research Society for the Study of Diabetes in India (RSSDI) clinical practice recommendations 2017 as add-on therapy after metformin and sulfonylurea in Type 2 Diabetes (T2DM) patients. The aim of this observational study is to compare the efficacy and safety of hydroxychloroquine 400 mg and teneligliptin 20 mg when used as add-on therapy in Indian Type 2 DM patients who were inadequately controlled (HbA1c ≥7.5%) with metformin 1000 mg and glimepiride 2 mg combination.

Methodology

This study is a prospective observational study to be conducted in 2 diabetic centres of Patna city between October 2017 and May 2018 involving 180 patients followed up for 6 months. One group (N=90) of patients received hydroxychloroquine 400 mg + metformin 1000 mg + glimepiride 2 mg, the other group (N=90) received teneligliptin 20 mg + metformin 1000 mg + glimepiride 2 mg. Efficacy was assessed by fasting blood glucose (FBG), post prandial blood glucose (PPBG) and glycated haemoglobin (HbA1c) reduction. Safety was evaluated by the number of hypoglycaemic events and changes in serum creatinine levels. Home based glucose monitoring was used to detect the hypoglycaemic events. Patients who had any type of retinopathy/maculopathy were excluded.

Results

Mean age of entire population was 66±8 years with mean 6±2 years of DM with 102 males. Mean body weight was 71±12 kg. Baseline HbA1c was 8.1±0.3 in the hydroxychloroquine group and 8.2±0.2 in the teneligliptin group.At 24 weeks there were statistically significant reductions in mean HbA1c in the hydroxychloroquine group (1.1±0.3) as compared to the teneligliptin group (0.82±0.3) (P≤0.001). The mean FBG and PPBG was 169±18 mg/dl and 232±18 mg/dl respectively in hydroxychloroquine group which was reduced to 121±15 mg/dl and 161±19 mg/dl at the end of 24 weeks. In the teneligliptin group, FBG and PPBG was 171±16 mg/dl and 239±21 mg/dl at baseline, which was reduced to 121±15 mg/dl and 161±19 mg/dl respectively in same period of time (P≤ 0.005). There were 4 incidences of hypoglycaemic events in the hydroxychloroquine group (4.4%) and 6 in the teneligliptin group (6.67%). No patients required medical assistance for hypoglycaemic events. There was no statistically significant change in body weight in both the groups. No marked changes in creatinine levels were found in patients in both the groups.

Conclusion

In conclusion, treatment with hydroxychloroquine 400 mg for 24 weeks reduces glycaemic parameters more aggressively than teneligliptin 20 mg in Indian type 2 diabetes patients.

In vitro Screening and Evaluation of 37 Traditional Chinese Medicines for Their Potential to Activate Peroxisome Proliferator-Activated Receptors-γ

BACKGROUND

Peroxisome proliferator-activated receptors (PPAR)-γ is widely used as an attractive target for the treatment of type 2 diabetes mellitus. Thiazolidinediones, the agonists of PPARγ, has been popularly utilized as insulin sensitizers in the therapy of type 2 diabetes whereas numerous severe side-effects may also occur concomitantly.

OBJECTIVE

The PPARγ activation activity of different polar extracts, including petroleum ether, ethyl acetate, n-butanol, residual of ethanol, the precipitate part of water and the supernatant of water extracts, from 37 traditional Chinese medicines were systematically evaluated.

MATERIALS AND METHODS

HeLa cells were transiently co-transfected with the re-constructed plasmids of GAL4-PPARγ-ligand binding domain and pGL4.35. The activation of PPARγ by different polarity extracts were evaluated based on the PPARγ transactivation assay and rosiglitazone was used as positive control.

RESULTS

Seven medicines (root bark of Lycium barbarum, Anoectochilus sroxburghii, the rhizome of Phragmites australis, Pterocephalus hookeri, Polygonatum sibiricum, fruit of Gleditsia sinensis, and Epimedium brevicornu) were able to significantly activate PPARγ.

CONCLUSION

As seven medicines were able to activate PPARγ, the anti-diabetic activity of them is likely to be mediated by this nuclear receptor.

SUMMARY

Lots of the tested medicinal products had activation effects on activating PPARγEthyl acetate extracts of root bark of L.barbarum, rhizome of P.saustralis and fruit of G.siasinensis showed good PPARγ activation effect similar or higher than that of positive control, 0.5 μg/mL rosiglitazonePetroleum ether extracts of A.roxburghii, P. hookeri, P. sibiricum, E.brevicornu also can significantly activate PPARγ, the effects of them were higher than t0.5 μg/mL rosiglitazoneSchisandra chinensis (Turcz.) Baill., the fruit Cornus officinalis Siebold and Zucc., Alisma plantago-aquatica L. and the root of Trichosanthes Kirilowii Maxim., traditional anti-diabetic mediciness in China, had no effects on the activation of PPARγ. Abbreviations used: PPARγ: Peroxisome Proliferator-activated Receptors-γ, TCMs: Traditional Chinese medicines, TZDs: Thiazolidinediones, LBD: Ligand binding domain, DMSO: Dimethyl sulfoxide, FBS: Fetal bovine serum, DMEM: Dulbecco's modified Eagle's medium.

Prevention of type 2 diabetes; a systematic review and meta-analysis of different intervention strategies

AIM

Different intervention strategies can prevent type 2 diabetes (T2DM). Aim of the present systematic review and meta-analysis was to evaluate the effectiveness of different strategies.

METHODS

Studies were grouped into 15 different strategies: 1: diet plus physical activity; 2: physical activity; 3-6: anti-diabetic drugs [glitazones, metformin, beta-cell stimulating drugs (sulphanylureas, glinides), alfa-glucosidase inhibitors]; 7-8: cardiovascular drugs (ACE inhibitors, ARB, calcium antagonists); 9-14 [diets, lipid-affecting drugs (orlistat, bezafibrate), vitamins, micronutrients, estrogens, alcohol, coffee]; 15: bariatric surgery. Only controlled studies were included in the analysis, whether randomized, non-randomized, observational studies, whether primarily designed to assess incident cases of diabetes, or performed with other purposes, such as control of hypertension, of ischemic heart disease or prevention of cardiovascular events. Appropriate methodology [preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement] was used. Seventy-one studies (490 813 subjects), published as full papers, were analysed to identify predictors of new cases of T2DM, and were included in a meta-analysis (random-effects model) to study the effect of different strategies. Intervention effect (new cases of diabetes) was expressed as odds ratio (OR), with 95% confidence intervals (C.I.s). Publication bias was formally assessed.

RESULTS

Body mass index was in the overweight range for 13 groups, obese or morbidly obese in lipid-affecting drugs and in bariatric surgery. Non-surgical strategies, except for beta-cell stimulating drugs, estrogens and vitamins, were able to prevent T2DM, with different effectiveness, from 0.37 (C.I. 0.26-0.52) to 0.85 (C.I. 0.77-0.93); the most effective strategy was bariatric surgery in morbidly obese subjects [0.16 (C.I. 0.11,0.24)]. At meta-regression analysis, age of subjects and amount of weight lost were associated with effectiveness of intervention.

CONCLUSIONS

These data indicate that several strategies prevent T2DM, making it possible to make a choice for the individual subject.

Metabolic syndrome and polycystic ovary syndrome: an intriguing overlapping

Metabolic syndrome is an increasing pathology in adults and in children, due to a parallel rise of obesity. Sedentary lifestyle, food habits, cultural influences and also a genetic predisposition can cause dyslipidemia, hypertension, abdominal obesity and insulin resistance which are the two main features of metabolic syndrome. Polycystic ovary syndrome (PCOS) is a condition directly associated with obesity, insulin resistance (HOMA index) and metabolic syndrome, and it is very interesting for its relationship and overlap with the metabolic syndrome. The relationship between the two syndromes is mutual: PCOS women have a higher prevalence of metabolic syndrome and also women with metabolic syndrome commonly present the reproductive/endocrine trait of PCOS. Prevention and treatment of metabolic syndrome and PCOS are similar for various aspects. It is necessary to treat excess adiposity and insulin resistance, with the overall goals of preventing cardiovascular disease and type 2 diabetes and improving reproductive failure in young women with PCOS. First of all, lifestyle changes, then pharmacological therapy, bariatric surgery and laparoscopic ovarian surgery represent the pillars for PCOS treatment.

White blood cells count and incidence of type 2 diabetes in young men

OBJECTIVE

Association between white blood cell (WBC) count and diabetes risk has been recently suggested. We assessed whether WBC count is an independent risk factor for diabetes incidence among young healthy adults.

RESEARCH DESIGN AND METHODS

WBC count was measured in 24,897 young (mean age 30.8 ± 5.36 years), normoglycemic men with WBC range of 3,000 to 12,000 cells/mm(3). Participants were periodically screened for diabetes during a mean follow-up of 7.5 years.

RESULTS

During 185,354 person-years of follow-up, diabetes was diagnosed in 447 subjects. A multivariate model adjusted for age, BMI, family history of diabetes, physical activity, and fasting glucose and triglyceride levels revealed a 7.6% increase in incident diabetes for every increment of 1,000 cells/mm(3) (P = 0.046). When grouped in quintiles, a baseline WBC count above 6,900 cells/mm(3) had an independent 52% increase in diabetes risk (hazard ratio 1.52 [95% CI 1.06-2.18]) compared with the lowest quintile (WBC <5,400 cells/mm(3)). Men at the lowest WBC quintile were protected from diabetes incidence even in the presence of overweight, family history of diabetes, or elevated triglyceride levels. After simultaneous control for risk factors, BMI was the primary contributor of the variation in multivariate models (P < 0.001), followed by age and WBC count (P < 0.001), and family history of diabetes and triglyceride levels (P = 0.12).

CONCLUSIONS

WBC count, a commonly used and widely available test, is an independent risk factor for diabetes in young men at values well within the normal range.

Is thiazolidinediones use a factor in delaying the need for insulin therapy in type 2 patients with diabetes? A population-based cohort study

OBJECTIVE

To understand the independent role of thiazolidinediones (TZDs) in delaying progression to parenteral insulin therapy.

DESIGN

Population-based retrospective cohort study.

SETTING

British Columbia, Canada.

PARTICIPANTS

A total of 18 867 type 2 diabetes patients (mean age 58.9) treated with metformin as first-line therapy who then switched or added a TZD or sulphonylurea as a second-line treatment between 1 January 1998 and 31 March 2008.

OUTCOME MEASURES

Multivariable Poisson regression models were used to estimate the effect of using TZD compared to sulphonylureas on time to the initiation of insulin treatment (third-line).

RESULTS

The adjusted rate difference in women aged <60 showed 2.22 fewer insulin initiation events per 100 person-years (PYs) in the TZD group versus the sulphonylurea group (95% CI -3.46 to -0.99). Men in the same age group had 1.50 fewer insulin initiation events per 100 PYs in the TZD group versus the sulphonylurea group (95% CI -2.44 to -0.56). The average time in days to initiation on insulin in the sulphonylurea, rosiglitazone and pioglitazone group was 343, 252 and 339, respectively. The cumulative hazard for starting insulin for sulphonylurea patients at 12, 24, 36 and 48 months was approximately three times higher compared to TZD patients.

CONCLUSIONS

Second-line TZD therapy compared to second-line sulphonylurea therapy was associated with a lower incidence of insulin initiation as third-line treatment in patients with type 2 diabetes, with a mean delay of 90 days. This duration of delay must be weighed against the absence of a proven reduction in morbidity or mortality with TZDs and their known serious cardiovascular harm.

Management of nonalcoholic steatohepatitis: an evidence-based approach

Nonalcoholic fatty liver disease (NAFLD) and its progressive form, nonalcoholic steatohepatitis (NASH), are an increasingly common cause of chronic liver disease in the developed world, with NASH projected to be the leading cause of liver transplantation in the United States by 2020. This review of NASH management addresses current data from the perspective of levels of evidence for therapeutic options in NASH, including lifestyle modification, drug therapies, and bariatric surgery. In particular, behavioral therapies to assist patients in adopting lifestyle changes are highlighted and a research agenda for future NASH management is presented.

New oral antidiabetic agents

The pathophysiology of hyperglycemia in type 2 diabetes (T2DM) involves 3 main defects: insulin deficiency, excess hepatic glucose output, and insulin resistance. Oral anti-diabetic agents act in a variety of ways. These include agents that stimulate insulin secretion, reduce hepatic glucose production, delay digestion and absorption of intestinal carbohydrate or improve insulin action. Because of improved knowledge of pathophysiology, new drugs with mechanisms of action focussed on specific pathophysiological alterations have appeared, in order to utilize all the possibilities of treating this condition. Here, we focus on the new agents used in the latest years and the overcoming ones in future, in particular incretin-based therapies, drugs inhibiting kidney glucose reabsorption (SGLT2 inhibitors), and glucokinase activators. The strategy for new drug development advocated here is to establish a broad range of anti-diabetic medicines with different mechanisms of action and potential opportunities for effective combination therapies.

Sitagliptin-induced hemolysis

Sitagliptin is a newer oral hypoglycemic drug of the dipeptidyl peptidase-IV inhibitor class. It appears to be a promising newer oral hypoglycemic agent. The advantages are the absence of hypoglycemia when used as monotherapy and they cause less gain weight. We report a case of sitagliptin-induced hemolysis, a rare side effect, not reported in the literature. As sitagliptin is widely used in type 2 diabetes mellitus physicians should be aware of the possibility of this rare but potentially serious adverse drug reaction.

The Role of PPARgamma in the Cyclooxygenase Pathway in Lung Cancer

Decreased expression of peroxisome proliferator activated receptor-γ (PPARγ) and high levels of the proinflammatory enzyme cyclooxygenase-2 (COX-2) have been observed in many tumor types. Both reduced (PPARγ) expression and elevated COX-2 within the tumor are associated with poor prognosis in lung cancer patients, and recent work has indicated that these signaling pathways may be interrelated. Synthetic (PPARγ) agonists such as the thiazolidinedione (TZD) class of anti-diabetic drugs can decrease COX-2 levels, inhibit growth of non-small-cell lung cancer (NSCLC) cells in vitro, and block tumor progression in xenograft models. TZDs alter the expression of COX-2 and consequent production of the protumorigenic inflammatory molecule prostaglandin E2 (PGE2) through both (PPARγ) dependent and independent mechanisms. Certain TZDs also reduce expression of PGE2 receptors or upregulate the PGE2 catabolic enzyme 15-prostaglandin dehydrogenase. As several COX-2 enzymatic products have antitumor properties and specific COX-2 inhibition has been associated with increased risk of adverse cardiac events, directly reducing the effects or concentration of PGE2 may provide a more safe and effective strategy for lung cancer treatment. Understanding the mechanisms underlying these effects may be helpful for designing anticancer therapies. This article summarizes recent research on the relationship between (PPARγ), TZDs, and the COX-2/PGE2 pathways in lung cancer.

PPAR Ligands as Potential Modifiers of Breast Carcinoma Outcomes

Chemically synthesized ligands for nuclear receptors of the PPAR family modulate a number of physiological functions, particularly insulin resistance in the context of energy homeostasis and the metabolic syndrome. Additionally, these compounds may treat or prevent the development of many secondary consequences of the metabolic syndrome. Many PPAR agonists are also known to influence the proliferation and apoptosis of breast carcinoma cells though the experiments were carried out at suprapharmacological doses of PPAR ligands. It is possible that the breast epithelium of diabetics exposed to PPAR agonists will experience perturbation of the corresponding signaling pathway. Consequently, these patients' lifetime breast carcinoma risks could be modified, as their breast lesion incidence or the rates of the conversion of these lesions to carcinomas might vary upward or downward. PPAR activating treatment may also influence the progression of existing, undiagnosed invasive lesions. In this review, we attempt to summarize the possible influence of chemical PPAR ligands on the molecular pathways involved in the initiation and progression of breast carcinoma, with a major emphasis on PPARγ agonists thiazolidinediones (TZDs).

Prevention and current onset delay approaches of type 2 diabetes mellitus (T2DM)

The urgent need to treat type 2 diabetes mellitus (T2DM), which is currently reaching epidemic proportions, has been a major focus of healthcare systems and policy makers worldwide. Pharmacological treatment and lifestyle interventions together with the control of cardiovascular risk factors are the main strategies to prevent or delay the onset of T2DM. The present review discusses the state of the art knowledge of effective therapeutic approaches (metformin, thiazolidinediones, nateglinides, α-glucosidase inhibitors, incretin-based and angiotensin-based therapies, weight reducers, statins, fibric acid derivatives), including surgery, and identifies the major lifestyle changes for specific target groups.

Defining and achieving treatment success in patients with type 2 diabetes mellitus

Traditionally, successful treatment of patients with type 2 diabetes mellitus (DM) has been defined strictly by achievement of targeted glycemic control, primarily using a stepped-care approach that begins with changes in lifestyle combined with oral therapy that is slowly intensified as disease progression advances and β-cell function declines. However, stepped care is often adjusted without regard to the mechanism of hyperglycemia or without long-term objectives. A more comprehensive definition of treatment success in patients with type 2 DM should include slowing or stopping disease progression and optimizing the reduction of all risk factors associated with microvascular and macrovascular disease complications. To achieve these broader goals, it is important to diagnose diabetes earlier in the disease course and to consider use of more aggressive combination therapy much earlier with agents that have the potential to slow or halt the progressive β-cell dysfunction and loss characteristic of type 2 DM. A new paradigm for managing patients with type 2 DM should address the concomitant risk factors and morbidities of obesity, hypertension, and dyslipidemia with equal or occasionally even greater aggressiveness than for hyperglycemia. The use of antidiabetes agents that may favorably address cardiovascular risk factors should be considered more strongly in treatment algorithms, although no pharmacological therapy is likely to be ultimately successful without concomitant synergistic lifestyle changes. Newer incretin-based therapies, such as glucagon-like peptide 1 receptor agonists and dipeptidyl peptidase 4 inhibitors, which appear to have a favorable cardiovascular safety profile as well as the mechanistic possibility for a favorable cardiovascular risk impact, are suitable for earlier inclusion as part of combination regimens aimed at achieving comprehensive treatment success in patients with type 2 DM.

Effects of ethnicity on diabetes incidence and prevention: results of the Diabetes REduction Assessment with ramipril and rosiglitazone Medication (DREAM) trial

AIMS

Risk of Type 2 diabetes varies by ethnicity, but whether ethnicity remains important among those who have impaired glucose tolerance or impaired fasting glucose is uncertain. Whether the effect of thiazolidinedione treatment on diabetes prevention in persons with non-diabetic dysglycaemia varies by ethnicity is also not known. We addressed these questions using data collected in the DREAM trial.

METHODS

A 2-by-2 factorial double-blind randomized controlled trial to compare the effects of rosiglitazone and ramipril on the primary outcome of diabetes or death in persons meeting criteria for impaired glucose tolerance or impaired fasting glucose. The effect of these interventions by ethnicity was estimated using Cox regression analysis.

RESULTS

Of 5269 adults, 2365 were randomly assigned to rosiglitzone and 2634 to placebo. South Asians showed a higher hazard for the primary outcome compared with Europeans (hazard ratio, 95% confidence interval 2.21, 1.41-3.47) adjusted for age, gender, BMI, waist-hip ratio and geographic region. A lesser increase in risk was seen in Black people (1.37, 1.04-1.81). A significant reduction in risk of the primary outcome with rosiglitazone treatment assignment was seen in all ethnic groups, but the treatment effect significantly differed by ethnicity (P=0.0242), with South Asians experiencing a smaller, and Latinos a larger preventive effect.

CONCLUSIONS

Ethnicity is an important risk factor for Type 2 diabetes in dysglycaemic persons. All ethnic groups experienced a large significant reduction in diabetes risk because of rosiglitazone. The magnitude of this reduction differed by ethnicity. Given the post hoc nature of this analysis, further confirmation of these findings is needed.

Meta-analysis: insulin sensitizers for the treatment of non-alcoholic steatohepatitis

BACKGROUND

Non-alcoholic fatty liver disease generally has a benign course; however, patients with non-alcoholic steatohepatitis (NASH) may progress to cirrhosis and hepatocellular carcinoma. Currently, there is a lack of consensus about optimal NASH treatment.

AIM

To assess the efficacy of insulin-sensitizing agents on histological and biochemical outcomes in randomized control trials of biopsy-proven NASH.

METHODS

Multiple online databases and conference abstracts were searched. Random effects meta-analyses were performed, with assessment for heterogeneity and publication bias.

RESULTS

Nine trials were included; five trials using thiazolidinediones (glitazones), three using metformin and one trial using both drugs. There was no publication bias. Compared with controls, glitazones resulted in improved steatosis (WMD = 0.57, 95% CI 0.36-0.77, P = <0.001), hepatocyte ballooning (WMD = 0.36, 95% CI 0.24-0.49, P < 0.001) and ALT (WMD = 16.4, 95% CI 7.7-25.0, P < 0.001), but not inflammation (P = 0.09) or fibrosis (P = 0.11). In patients without diabetes, glitazones significantly improved all histological and biochemical outcomes, most importantly including fibrosis (WMD = 0.29, 95% CI 0.078-0.51, P = 0.008). Metformin failed to improve any pooled outcome.

CONCLUSIONS

Treatment of NASH with glitazones, but not metformin, demonstrates a significant histological and biochemical benefit, especially in patients without diabetes. Additional studies are needed to investigate long-term outcomes of glitazone therapy in patients without diabetes.

Prevention and treatment of nonalcoholic fatty liver disease

A better knowledge of the biochemical mechanisms implicated in the development and progression of nonalcoholic fatty liver disease, linking fatty liver to insulin resistance and the metabolic syndrome, has shifted the goal of treatment from a mere clearing of fat from the liver to a systematic treatment of metabolic risk factors for fatty liver. Any attempt to modify the "unhealthy" habits responsible for fatty liver requires an integrated approach, based on the cognitive theory of behaviour by a multidisciplinary team including physicians, psychologists, dieticians and physical exercise experts, and recent data demonstrate that this is feasible and effective. Whenever this goal is not attained, a treatment based on insulin-sensitizers remains the best option, to simultaneously tackle all metabolic alterations of the metabolic syndrome. However, in individual patients, both raised blood pressure and dyslipidemia need to be controlled, in order to reduce cardiovascular risk. In these areas, any attempt should be made to use of drugs less likely to induce a deterioration of glucose control. It remains to be determined whether these treatments are able to modify the natural history of nonalcoholic fatty liver disease in the long term.

Molecular mechanism by which pioglitazone preserves pancreatic beta-cells in obese diabetic mice: evidence for acute and chronic actions as a PPARgamma agonist

Pioglitazone preserves pancreatic beta-cell morphology and function in diabetic animal models. In this study, we investigated the molecular mechanisms by which pioglitazone protects beta-cells in diabetic db/db mice. In addition to the morphological analysis of the islets, gene expression profiles of the pancreatic islet were analyzed using laser capture microdissection and were compared with real-time RT-PCR of db/db and nondiabetic m/m mice treated with or without pioglitazone for 2 wk or 2 days. Pioglitazone treatment (2 wk) ameliorated dysmetabolism, increased islet insulin content, restored glucose-stimulated insulin secretion, and preserved beta-cell mass in db/db mice but had no significant effects in m/m mice. Pioglitazone upregulated genes that promote cell differentiation/proliferation in diabetic and nondiabetic mice. In db/db mice, pioglitazone downregulated the apoptosis-promoting caspase-activated DNase gene and upregulated anti-apoptosis-related genes. The above-mentioned effects of pioglitazone treatment were also observed after 2 days of treatment. By contrast, the oxidative stress-promoting NADPH oxidase gene was downregulated, and antioxidative stress-related genes were upregulated, in db/db mice treated with pioglitazone for 2 wk, rather than 2 days. Morphometric results for proliferative cell number antigen and 4-hydroxy-2-noneal modified protein were consistent with the results of gene expression analysis. The present results strongly suggest that pioglitazone preserves beta-cell mass in diabetic mice mostly by two ways; directly, by acceleration of cell differentiation/proliferation and suppression of apoptosis (acute effect); and indirectly, by deceleration of oxidative stress because of amelioration of the underlying metabolic disorder (chronic effect).

Preserving insulin secretion in Type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a complex disease characterized by insulin resistance and a progressive decline in β-cell function and mass. Current evidence suggests that β-cell dysfunction is present early in the course of the disease and that this dysfunction, rather than insulin resistance, is primarily responsible for the progression of T2DM. β-cell dysfunction can be accelerated by glucose toxicity, lipotoxicity, oxidative stress, chronic increases in inflammatory mediators and, potentially, the use of sulfonylureas. This review suggests that future efforts to limit the impact of T2DM must focus on strategies to preserve β-cell function. Several interventions have shown promise in this regard, including lifestyle modifications, thiazolidinediones, potassium channel openers, incretin mimetics, cytokine antagonists, bariatric surgery and dipeptidyl peptidase IV inhibitors, although therapeutic insulin remains the most robust and physiological approach.

Peroxisome proliferator-activated receptor-gamma agonists and diabetes: current evidence and future perspectives

Since their initial availability in 1997, the thiazolidinediones (TZDs) have become one of the most commonly prescribed classes of medications for type 2 diabetes. In addition to glucose control, the TZDs have a number of pleiotropic effects on myriad traditional and non-traditional risk factors for diabetes. TZDs may benefit cardiovascular parameters, such as lipids, blood pressure, inflammatory biomarkers, endothelial function and fibrinolytic state. In this review, we summarise the experimental, preclinical and clinical data regarding the effects of the TZDs in conditions for which they are indicated and discuss their potential in the treatment of other conditions.

The importance of beta-cell management in type 2 diabetes

Despite intervention with effective oral glucose-lowering agents, most patients with type 2 diabetes will experience a gradual loss of glycaemic control. Irrespective of underlying levels of insulin resistance, the progressive failure and loss of beta-cells are ultimately responsible for the onset of frank type 2 diabetes. The mechanisms responsible for loss of beta-cell function are likely to be multifactorial, but may involve toxicity because of elevated glucose and/or lipid levels, increased secretory demand because of insulin resistance, amyloid deposition and altered levels of cytokines. Preservation of beta-cell function is now gaining recognition as a critical target in the management of type 2 diabetes. For patients with frank type 2 diabetes, preservation of beta-cell function has the potential to reduce or stabilise the progression of type 2 diabetes and to decrease the need for additional oral glucose-lowering agents and/or insulin therapy. There is a growing body of animal/preclinical evidence for improved and preserved beta-cell function with current glucose-lowering agents, such as the thiazolidinediones, metformin and the glucagon-like peptide-1 analogue, exenatide. Clinical studies incorporating indirect measures of beta-cell function also support a protective effect with some agents. A number of novel therapies that are currently under investigation may also offer beta-cell structural and functional protection, including dipeptidyl peptidase IV inhibitors and cannabinoid receptor type 1 blockers. Emerging evidence from interventional trials suggests that both intensive lifestyle changes and pharmacotherapy can delay or possibly prevent the onset of type 2 diabetes in high-risk individuals. For patients newly diagnosed with type 2 diabetes, early and aggressive intervention strategies that combine maximal glucose-lowering efficacy alongside potential beta-cell preserving properties may provide an opportunity to delay or prevent progression of the disease.

Glucose intolerance in polycystic ovary syndrome--a position statement of the Androgen Excess Society

OBJECTIVES

Women with polycystic ovarian syndrome (PCOS) are at increased risk for developing glucose intolerance and type 2 diabetes mellitus (DM). Recommendations for the timing and method of screening have varied. The purpose of this statement is to determine the optimal screening method, timing of screening, and treatment modalities for impaired glucose tolerance (IGT) among women with PCOS.

PARTICIPANTS

The expert panel was appointed by the Androgen Excess Society (AES) to review the literature and make recommendations based on the available evidence. Meetings were open, and there was no funding for the panel.

EVIDENCE

A systematic review was conducted of the published, peer-reviewed medical literature using MEDLINE to identify studies that addressed the prevalence, risk factors, testing, and treatment for IGT in both adults and adolescents with PCOS. Unpublished data were not considered.

CONSENSUS PROCESS

The panel held meetings to review the literature and draft the statement as a committee. The AES board members reviewed and critiqued the manuscript, and changes were made based on their comments.

CONCLUSIONS

The panel recommends that all patients with PCOS be screened for IGT with a 2-h oral glucose tolerance test. A few members of the AES board recommend alternatively screening women with PCOS for IGT and type 2 DM using an oral glucose tolerance test only in patients with a body mass index of 30 kg/m2 or greater or in lean patients with additional risk factors. Patients with normal glucose tolerance should be rescreened at least once every 2 yr, or more frequently if additional risk factors are identified. Those with IGT should be screened annually for development of type 2 DM. PCOS patients with IGT should be treated with intensive lifestyle modification and weight loss and considered for treatment with insulin-sensitizing agents.

Inflammation and lung carcinogenesis: applying findings in prevention and treatment

Lung carcinogenesis is a complex process requiring the acquisition of genetic mutations that confer the malignant phenotype as well as epigenetic alterations that may be manipulated in the course of therapy. Inflammatory signals in the lung cancer microenvironment can promote apoptosis resistance, proliferation, invasion, metastasis, and secretion of proangiogenic and immunosuppressive factors. Here, we discuss several prototypical inflammatory mediators controlling the malignant phenotype in lung cancer. Investigation into the detailed molecular mechanisms underlying the tumor-promoting effects of inflammation in lung cancer has revealed novel potential drug targets. Cytokines, growth factors and small-molecule inflammatory mediators released in the developing tumor microenvironment pave the way for epithelial-mesenchymal transition, the shift from a polarized, epithelial phenotype to a highly motile mesenchymal phenotype that becomes dysregulated during tumor invasion. Inflammatory mediators within the tumor microenvironment are derived from neoplastic cells as well as stromal and inflammatory cells; thus, lung cancer develops in a host environment in which the deregulated inflammatory response promotes tumor progression. Inflammation-related metabolic and catabolic enzymes (prostaglandin E(2) synthase, prostaglandin I(2) synthase and 15-hydroxyprostaglandin dehydrogenase), cell-surface receptors (E-type prostaglandin receptors) and transcription factors (ZEB1, SNAIL, PPARs, STATs and NF-kappaB) are differentially expressed in lung cancer cells compared with normal lung epithelial cells and, thus, may contribute to tumor initiation and progression. These newly discovered molecular mechanisms in the pathogenesis of lung cancer provide novel opportunities for targeted therapy and prevention in lung cancer.

Prevention of diabetes development in those with the metabolic syndrome

Metabolic syndrome is characterized by abnormal glucose levels, central obesity, hypertension, elevated triglycerides, and low HDL cholesterol. This article reviews available data regarding the impact of lifestyle modification and drug therapies on the progression to diabetes in high risk individuals, such as those with hypertension, dyslipidemia, obesity, and prediabetes. Lifestyle and pharmacological interventions may alter metabolic parameters and impact progression to diabetes. However, the cost-effectiveness of these interventions are unclear.

Normal fasting plasma glucose levels and type 2 diabetes: the high-risk and population strategy for occupational health promotion (HIPOP-OHP) [corrected] study

The objective of this study is to ascertain if higher normal fasting glucose levels are also an independent risk of developing diabetes in an Asian population, and we thus analysed data from a cohort of healthy Japanese workers. We used data from the non-randomised trial on health promotion intervention, High-risk and Population Strategy for Occupational Health Promotion (HIPOP-OHP) Study. Diabetes cases and those who had fasting blood glucose levels equal to or greater than 100 mg/dl at baseline were excluded, and the Cox proportional-hazards model was used for the analysis. During the four-year follow-up of 2212 participants, we found 37 diabetes cases. In the multivariable model, people with blood glucose levels in the 4th quartile had a higher risk of diabetes than those in the bottom quartile; the multivariable-adjusted odds ratio was 2.52. The risk of diabetes abruptly rose in persons with blood glucose levels higher than 94 mg/dl (fourth quartile). A significant linear trend was not observed in the 1st to 3rd quartiles (p=0.726). In conclusion, higher fasting glucose level was associated with the risk of diabetes, and we found a threshold in the association between fasting blood glucose levels and risk of diabetes in an Asian population.

The role of angiotensin II type 1 receptor blockers in the prevention and management of diabetes mellitus

Angiotensin II Receptor blockers (ARBs) are an important addition to the current range of medications available for treating a wide spectrum of diseases including cardiovascular diseases. Coronary heart disease (CHD) is the most common cause of death in the United Kingdom and worldwide. More importantly, the presence of the metabolic syndrome and the likelihood of diabetes mellitus taking on epidemic proportions in the years to come all threaten to maintain the mortality rate due to CHD. This review article focuses on the clinical studies that have helped define the trends in the usage of these agents in the prevention and treatment of diabetes mellitus and its complications and also explores possible mechanisms of action and future developments.

The different mechanisms of insulin sensitizers to prevent type 2 diabetes in OLETF rats

OBJECTIVE

To investigate the effects of pioglitazone and metformin treatment during pre-diabetic period for the prevention of diabetes in a rat model.

METHODS

OLETF rats aged 18-weeks, were treated with pioglitazone (10 mg/kg/day) and metformin (300 mg/kg/day) for 10 weeks from their pre-diabetic period. We measured weight, lipid profiles, fat distribution, glucose tolerance, and pancreatic insulin content.

RESULTS

Prominent weight gain (mostly subcutaneous fat area) was observed in the pioglitazone-treated OLETF (O-P) rats versus significant weight loss was observed in the metformin-treated OLETF (O-M) rats. Pioglitazone reversed the serum triglyceride (TG) and FFAs levels to normal (TG 0.46 +/- 0.04 vs 0.88 +/- 0.05 mmol/l in LETO). At the age of 28 weeks, the O-P rats showed completely normal glucose tolerance, and the glucose disposal rate (GDR) was markedly improved (25.6 +/- 0.4 vs 20.6 +/- 0.5 mg/min/kg in O-C, p < 0.05). The O-M rats also showed an improved fasting glucose and GDR level, but not as much as those with O-P rats. The pancreas insulin contents were much improved in the O-P rats (22.9 +/- 1.2 vs 18.8 +/- 1.3 nmol/pancreas in O-M rats, p < 0.05) with histological improvement.

CONCLUSION

The pre-diabetic treatment with pioglitazone, despite significant weight gain, completely prevents to develop diabetes and enhances beta cell function with preservation of islet cell changes. Metformin treatment was also effective, but mainly by ameliorating the insulin resistance with marked reduction in body weight. The reversal of dyslipidaemia and the fat redistribution might contribute to the greater improvement of pioglitazone treatment compared to metformin in OLETF rats.

PPARgamma activation by thiazolidinediones (TZDs) may modulate breast carcinoma outcome: the importance of interplay with TGFbeta signalling

The thiazolidinediones (TZDs) are a class of synthetic antidiabetic drugs exerting its action primarily upon acti-vation of the peroxisome proliferator-activated receptor-γ (PPARγ). Given the widespread incidence of diabetes type II and lifelong exposure of these patients to TZDs, there is a possibility that chronic treatment with TZD modifies clinical phenotypes of other common human diseases, for example breast carcinoma. There is evidence that TZDs act as breast carcinoma suppression agents, at least in the in vitro and animal models. Stimulation of the PPARγ by TZDs interferes with oestrogen receptor signalling, STAT5B and NF-κB signalling cascades. On the other hand, TZDs repress TGFβ signalling, a well-known suppressor of the initial stages of breast carcinoma development. Another layer of complexity arises at the later stages of tumour development, when TGFβ acts as a tumour promoter: its overexpression is associated with poor prognosis, higher degree of tumour vascularization and metastasis. Longitudinal studies of breast carcinoma development in chronic TZD users are needed. In this review, we dissect possible interplays between chronic exposure of breast tis-sue to TZDs and TGFβ signalling and predict influence of TZD exposure on cancer-related clinical outcome.

Beta-cell preservation with thiazolidinediones

Progressive beta-cell dysfunction and beta-cell failure are fundamental pathogenic features of type 2 diabetes. Ultimately, the development and continued progression of diabetes is a consequence of the failure of the beta-cell to overcome insulin resistance. Strategies that aim to prevent diabetes must, therefore, ultimately aim to stabilize the progressive decline of the beta-cell. Clinical study evidence from several sources now suggests that thiazolidinediones (TZDs) have profound effects on the beta-cell, such as improving insulin secretory capacity, preserving beta-cell mass and islet structure and protecting beta-cells from oxidative stress, as well as improving measures of beta-cell function, such as insulinogenic index and homeostasis model assessment of beta-cell function (HOMA-%B). Furthermore, intervention studies suggest that TZDs have the potential to delay, stabilize and possibly even prevent the onset on diabetes in high-risk individuals, and these effects appear to accompany improvements in beta-cell function. Here, we review the evidence, from in vitro studies to large intervention trials, for the effects of TZDs on beta-cell function and the consequences for glucose-lowering therapy.

Pioglitazone and rosiglitazone decrease prostaglandin E2 in non-small-cell lung cancer cells by up-regulating 15-hydroxyprostaglandin dehydrogenase

Lung cancer cells elaborate the immunosuppressive and antiapoptotic mediator prostaglandin E(2) (PGE(2)), a product of cyclooxygenase-2 (COX-2) enzyme activity. Because peroxisome proliferator-activated receptor (PPAR)gamma ligands, such as thiazolidinediones (TZDs), inhibit lung cancer cell growth, we examined the effect of the TZDs pioglitazone and rosiglitazone on PGE(2) levels in non-small-cell lung cancer (NSCLC) A427 and A549 cells. Both TZDs inhibited PGE(2) production in NSCLC cells via a COX-2 independent pathway. To define the mechanism underlying COX-2 independent suppression of PGE(2) production, we focused on other enzymes responsible for the synthesis and degradation of PGE(2). The expression of none of the three prostaglandin synthases (microsomal PGES1, PGES2 and cystosolic PGES) was down-regulated by the TZDs. It is noteworthy that 15-hydroxyprostaglandin dehydrogenase (15-PGDH), an enzyme that produces biologically inactive 15-ketoprostaglandins from active PGE(2), was induced by TZDs. The TZD-mediated suppression of PGE(2) concentration was significantly inhibited by small interfering RNA to 15-PGDH. Studies using dominant-negative PPARgamma overexpression or 2-chloro-5-nitrobenzanilide (GW9662; a PPARgamma antagonist) revealed that the suppressive effect of the TZDs on PGE(2) is PPARgamma-independent. Together, these findings indicate that it is possible to use a clinically available pharmacological intervention to suppress tumor-derived PGE(2) by enhancing catabolism rather than blocking synthesis.

Pharmacological interventions in the prevention of type 2 diabetes

(1) Diabetes is a chronic disease whose incidence is increasing worldwide. The long-term complications of diabetes place a large health and economic burden onto individuals, their families and communities as a whole.(2) Guidelines on the prevention of diabetes recommend lifestyle changes such as smoking cessation and weight loss to decrease type 2 diabetes incidence in patients with impaired glucose tolerance or impaired fasting glucose.(3) The role of lifestyle changes and weight loss in preventing diabetes has been proven in large, randomized, controlled clinical trials. To date, the evidence in favor of pharmacological methods is less robust; however, encouraging results obtained so far suggest a promising future role for these agents.(4) Several oral hypoglycemic agents and the antiobesity drug orlistat have been shown to significantly decrease progression to diabetes. The role of other agents such as statins, oestrogen and antihypertensive agents remains to be clarified in additional well-designed studies of diabetes prevention.

beta-cell failure in diabetes and preservation by clinical treatment

There is a progressive deterioration in beta-cell function and mass in type 2 diabetics. It was found that islet function was about 50% of normal at the time of diagnosis, and a reduction in beta-cell mass of about 60% was shown at necropsy. The reduction of beta-cell mass is attributable to accelerated apoptosis. The major factors for progressive loss of beta-cell function and mass are glucotoxicity, lipotoxicity, proinflammatory cytokines, leptin, and islet cell amyloid. Impaired beta-cell function and possibly beta-cell mass appear to be reversible, particularly at early stages of the disease where the limiting threshold for reversibility of decreased beta-cell mass has probably not been passed. Among the interventions to preserve or "rejuvenate" beta-cells, short-term intensive insulin therapy of newly diagnosed type 2 diabetes will improve beta-cell function, usually leading to a temporary remission time. Another intervention is the induction of beta-cell "rest" by selective activation of ATP-sensitive K+ (K(ATP)) channels, using drugs such as diazoxide. A third type of intervention is the use of antiapoptotic drugs, such as the thiazolidinediones (TZDs), and incretin mimetics and enhancers, which have demonstrated significant clinical evidence of effects on human beta-cell function. The TZDs improve insulin secretory capacity, decrease beta-cell apoptosis, and reduce islet cell amyloid with maintenance of neogenesis. The TZDs have indirect effects on beta-cells by being insulin sensitizers. The direct effects are via peroxisome proliferator-activated receptor gamma activation in pancreatic islets, with TZDs consistently improving basal beta-cell function. These beneficial effects are sustained in some individuals with time. There are several trials on prevention of diabetes with TZDs. Incretin hormones, which are released from the gastrointestinal tract in response to nutrient ingestion to enhance glucose-dependent insulin secretion from the pancreas, aid the overall maintenance of glucose homeostasis through slowing of gastric emptying, inhibition of glucagon secretion, and control of body weight. From the two major incretins, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), only the first one or its mimetics or enhancers can be used for treatment because the diabetic beta-cell is resistant to GIP action. Because of the rapid inactivation of GLP-1 by dipeptidyl peptidase (DPP)-IV, several incretin analogs were developed: GLP-1 receptor agonists (incretin mimetics) exenatide (synthetic exendin-4) and liraglutide, by conjugation of GLP-1 to circulating albumin. The acute effect of GLP-1 and GLP-1 receptor agonists on beta-cells is stimulation of glucose-dependent insulin release, followed by enhancement of insulin biosynthesis and stimulation of insulin gene transcription. The chronic action is stimulating beta-cell proliferation, induction of islet neogenesis, and inhibition of beta-cell apoptosis, thus promoting expansion of beta-cell mass, as observed in rodent diabetes and in cultured beta-cells. Exenatide and liraglutide enhanced postprandial beta-cell function. The inhibition of the activity of the DPP-IV enzyme enhances endogenous GLP-1 action in vivo, mediated not only by GLP-1 but also by other mediators. In preclinical studies, oral active DPP-IV inhibitors (sitagliptin and vildagliptin) also promoted beta-cell proliferation, neogenesis, and inhibition of apoptosis in rodents. Meal tolerance tests showed improvement in postprandial beta-cell function. Obviously, it is difficult to estimate the protective effects of incretin mimetics and enhancers on beta-cells in humans, and there is no clinical evidence that these drugs really have protective effects on beta-cells.

Metabolic syndrome, inflammation and atherosclerosis

The inflammatory component of atherogenesis has been increasingly recognized over the last decade. Inflammation participates in all stages of atherosclerosis, not only during initiation and during evolution of lesions, but also with precipitation of acute thrombotic complications. The metabolic syndrome is associated with increased risk for development of both cardiovascular disease and type-2 diabetes in humans. Central obesity and insulin resistance are thought to represent common underlying factors of the syndrome, which features a chronic low-grade inflammatory state. Diagnosis of the metabolic syndrome occurs using defined threshold values for waist circumference, blood pressure, fasting glucose and dyslipidemia. The metabolic syndrome appears to affect a significant proportion of the population. Therapeutic approaches that reduce the levels of proinflammatory biomarkers and address traditional risk factors are particularly important in preventing cardiovascular disease and, potentially, diabetes. The primary management of metabolic syndrome involves healthy lifestyle promotion through moderate calorie restriction, moderate increase in physical activity and change in dietary composition. Treatment of individual components aims to control atherogenic dyslipidemia using fibrates and statins, elevated blood pressure, and hyperglycemia. While no single treatment for the metabolic syndrome as a whole yet exists, emerging therapies offer potential as future therapeutic approaches.

Antidiabetic agents in subjects with mild dysglycaemia: prevention or early treatment of type 2 diabetes?

Besides lifestyle, various pharmacological treatments have proven their efficacy to reduce the incidence of type 2 diabetes in high-risk individuals, especially in those with impaired glucose tolerance (IGT) and/or impaired fasting glucose (IFG). Major placebo-controlled clinical trials demonstrated favourable effects of various glucose-lowering drugs generally used for the treatment of type 2 diabetes, i.e. metformin, acarbose and thiazolidinediones (glitazones). These trials showed a lower rate of progression to overt diabetes and a higher regression rate to a normal glucose status with active treatment as compared to placebo after a follow up of several years. Ongoing trials should confirm such a favourable effect with those drugs and may demonstrate a similar protective effect with other pharmacological approaches such as glinides or even basal insulin regimen. However, the reported favourable effects were generally observed while the subjects were still on treatment, and partially vanished after a rather short period of wash-out of several weeks. Therefore, the distinction between a true preventing effect and simply a masking effect is difficult with glucose-lowering drugs. In addition, as type 2 diabetes is a progressive disease, it is still questionable whether the effect corresponds to a prevention effect or only to a postponing of the development of the disease. Owing to the pathophysiology of the disease, the only way to block the progression of type 2 diabetes is probably to avoid the progressive loss of beta-cell function and/or mass. Whatsoever, these data obtained in large clinical trials bring further argument to support early treatment of diabetes, even at a prediabetic state, in order to stop the vicious circle leading to an inevitable deterioration of glycaemia in predisposed subjects.

Is prevention of Type-2 diabetes feasible and efficient in primary care? A systematic PubMed review

AIM

To answer: (1) Do we have effective treatments to improve prognosis for those identified at risk of Type-2 diabetes? (2) Will prevention be cost-effective?

METHODS

A systematic search was done in PubMed using the following search strategy: "diabetes AND prevention AND (IFG OR IGT)". Restrictions were: "English, Meta-Analysis, Randomized Controlled Trial, Review, Humans".

RESULTS

Few randomised controlled preventive trials were found. Almost all were done in research settings in people with high risk of developing Type-2 diabetes. It seems possible to either delay or prevent Type-2 diabetes through lifestyle interventions and medication. Cost-utility analyses are few in number and come to very different conclusions as to whether health policy should promote prevention of Type-2 diabetes.

CONCLUSION

Intervention studies using lifestyle counselling and drug therapy in research settings illustrate promising results with lowering of the incidence of Type-2 diabetes, meaning that Type-2 diabetes can be delayed or prevented. It is, however, questionable whether these interventions are cost-effective. We need studies in routine clinical settings evaluating morbidity, mortality and cost-effectiveness as primary outcomes. While waiting for these studies to prove cost-effective, patients with pre-diabetes should be treated according to their 10-year risk of cardiovascular disease following present guidelines.

Comparison of the Effects of Pioglitazone and Metformin on Insulin Resistance and Hormonal Markers in Patients with Impaired Glucose Tolerance and Early Diabetes

Impaired glucose tolerance (IGT) is associated with cardiovascular risk factors, but the effects of pioglitazone and metformin on IGT are not well described. We tested the hypothesis that each drug would exhibit antiatherogenic and anti-inflammatory effects in subjects with IGT and early diabetes. The study design was a prospective, randomized, open label, cross-over study. Blood tests, including a 75-g oral glucose tolerance test (OGTT), were performed at baseline and after each treatment. Pioglitazone 15 mg/day or metformin 500-750 mg/day was given for 3 months. Biochemical markers to assess insulin resistance as well as lipid, inflammatory, neurohumoral, and hemostatic factors were included. Twenty-five subjects (17 male, 8 female; age [mean+/-SD]: 61+/-9 years; 84% hypertensive) completed the protocol. Of 25 subjects, 14 were diagnosed as IGT and 11 as diabetes with 75-g OGTT. Pioglitazone significantly reduced fasting glucose (p<0.05), and homeostasis model assessment of insulin resistance (HOMA-IR) (p<0.05) and metformin (p<0.01) reduced cholesterol. Both drugs significantly reduced aldosterone (both p<0.05) and von Willebrand factor (vWF) (both p<0.05). Plasma adiponectin was increased only by pioglitazone (p<0.001). Neither drug affected BP levels. In conclusion, pioglitazone was superior to metformin for the improvement of insulin resistance and adiponectin, and both drugs were equally effective in reducing vWF and aldosterone in subjects with IGT and early diabetes. Early intervention with pioglitazone or metformin therapy may reduce the incidence of future cardiovascular disease in subjects with impaired glucose tolerance or early diabetes.

Insulin resistance and impaired beta cell function in rheumatoid arthritis

OBJECTIVE

To identify factors that regulate glucose metabolism in rheumatoid arthritis (RA).

METHODS

We evaluated the homeostatic model assessment of insulin resistance (HOMA-IR) and beta cell function (HOMA-B) in 94 RA patients. We investigated the relationship between characteristics known to affect glucose metabolism in the general population (age, abdominal obesity [waist circumference], hypertension, antihypertensive therapy) as well as characteristics of RA (disease activity, glucocorticoid therapy) and insulin resistance and beta cell function.

RESULTS

Patients with high-grade inflammation (high-sensitivity C-reactive protein value >1.92 mg/liter) (n = 81) were more insulin resistant than patients with low-grade inflammation (n = 13), whereas beta cell function was similar in both groups. Insulin resistance and beta cell function were similar in both groups after adjustment for waist circumference. All recorded characteristics except for age were associated with HOMA-IR or/and HOMA-B in univariate analyses. In mixed regression models, abdominal obesity and patient's assessment of disease activity (by visual analog scale) were predictors of insulin resistance. The Disease Activity Score assessed using 28-joint counts for swelling and tenderness, tender joint count, and patient's assessment of disease activity were associated with reduced beta cell function, and the cumulative dose of glucocorticoids was associated with enhanced beta cell function. The cumulative glucocorticoid dose in all study patients was a mean of only 536 mg (95% confidence interval 239-1,173). In patients with high-grade inflammation, age was further associated with impaired beta cell function, whereas use of angiotensin-converting enzyme inhibitors or angiotensin II type 1 receptor blockers was associated with enhanced beta cell function.

CONCLUSION

The modifiable factors of abdominal obesity, antihypertensive therapy, disease activity, and use of glucocorticoids appear to affect glucose metabolism in RA.

Adverse effects of reactive oxygen species on vascular reactivity in insulin resistance

Insulin resistance (IR) has adverse effects on the reactivity of arteries and arterioles and promotes arterial hypertension and vascular occlusive diseases. Altered reactivity of resistance vessels occurs at both the endothelium and smooth-muscle levels. One major mechanism of vascular dysfunction with IR involves the augmented generation, availability, and/or actions of reactive oxygen species (ROS). Scavengers of ROS are able immediately to restore normal dilator responsiveness in arteries from IR animals. Other factors, such as increased importance of constrictor agents such as endothelin, also restrict normal dilator responses. The basis of ROS-mediated vascular dysfunction in IR may be secondary to underlying inflammatory processes throughout the arterial wall. Although ROS scavengers may be beneficial in the short term, prolonged treatments involving behavioral approaches, such as changes in diet, weight loss, and regular exercise, and pharmacological approaches, involving the use of insulin-sensitizing agents, inhibitors of the renin-angiotensin system, or administration of statins, appear to offer benefits against the detrimental vascular effects of IR. Nonetheless, the most effective approach appears to involve prevention of IR via adoption of a healthy lifestyle by young people.

Closing the gap between clinical research and clinical practice: can outcome studies with thiazolidinediones improve our understanding of type 2 diabetes?

Recent clinical research has provided a wealth of information to support optimal management strategies in type 2 diabetes mellitus (T2DM). In particular, outcome studies appropriately have had an increasingly important impact on clinical decision-making. Additional, new data are required, however, to close the current gaps in clinical knowledge and improve patient outcomes in T2DM. These outcome studies are particularly important in assessing the long-term benefit of newer agents for which data are available for short-term glycaemic control, effects on lipids and some data on non-traditional cardiovascular risk markers, but outcome data for harder end points relevant to the natural history of T2DM, particularly beta-cell function, are lacking. Outcome studies such as ADOPT and DREAM are investigating the impact of thiazolidinediones (TZDs) on beta-cell function and disease progression in T2DM and impaired glucose tolerance, respectively, the results of which are eagerly anticipated. The primary focus of this article is on TZD outcome studies evaluating beta-cell function and disease progression.