Muxun Zhang

Plasma Heme Oxygenase-1 Concentration Is Elevated in Individuals with Type 2 Diabetes Mellitus

Background Circulating concentrations of heme oxygenase-1 (HO-1) have been recently reported to be elevated in several chronic disorders. However, no study has ever examined the association between circulating HO-1 concentrations and type 2 diabetes mellitus (T2DM). Methods and Findings 581 cases with newly-diagnosed T2DM (New-T2DM) and 611 comparison controls were recruited in this two-phase case-control study, comprising 420 cases and 429 controls collected in the first phase study and 161 cases and 182 controls in the second phase replication study. Analyses, using both separated data and combined data from the two-phase studies, show that plasma HO-1 concentrations were significantly increased in New-T2DM cases compared to controls (P<0.001). Plasma HO-1 concentrations were significantly correlated with plasma glucose concentrations, HOMA-beta and HOMA-IR (P<0.001). After adjustment for age, sex, BMI and family history of diabetes, the ORs for New-T2DM in the highest quartile of plasma HO-1 concentrations, compared with the lowest, was 8.23 (95% CI 5.55–12.21; P for trend <0.001). The trend remained significant after additional adjustment for fasting plasma glucose/insulin, HOMA-beta/HOMA-IR, TC/TG, smoking, drinking and history of hypertension, and even in further stratification analysis by age, sex, BMI, smoking, drinking and history of hypertension. Conclusions Elevated plasma HO-1 concentrations are associated with higher ORs for New-T2DM, which add more knowledge regarding the important role of oxidative stress in T2DM. More consequent studies were warranted to confirm the clinical utility of plasma HO-1, especially in diagnosis and prognosis of T2DM and its complications.

Association Between Heme Oxygenase-1 Gene Promoter Polymorphisms and Type 2 Diabetes in a Chinese Population

The authors aimed to determine whether 2 functional polymorphisms in the heme oxygenase-1 (HO-1) gene promoter are associated with type 2 diabetes mellitus (T2DM). A Chinese case-control study involving 1,103 newly diagnosed T2DM patients, 371 patients with impaired glucose regulation (IGR), and 1,615 controls was performed (December 2004-December 2007). A (GT)(n) microsatellite polymorphism and a single nucleotide polymorphism, T(-413)A, were genotyped, and their functional relevance was evaluated by examining the level of HO-1 protein expression. For the (GT)(n) microsatellite polymorphism, genotypes with the L (GT)(n) allele (>or=25 GT repeats) were associated with increased odds of IGR or T2DM compared with the S/S genotype (<25 GT repeats) (S/L genotype: odds ratio (OR) = 1.35, P = 0.048; L/L genotype: OR = 1.65, P = 0.006). Subsequent haplotype analysis showed that haplotype TL contributed to increased odds of IGR or T2DM compared with haplotype TS (OR = 1.56, P = 0.003). In functional analyses, HO-1 expression level was significantly reduced in persons with IGR and T2DM carrying the L/L (GT)(n) genotype compared with persons with the S/S genotype. Further haplotype combination assay confirmed the functional dominance of the (GT)(n) microsatellite polymorphism over the T(-413)A single nucleotide polymorphism. These results support an association between the HO-1 (GT)(n) microsatellite polymorphism, HO-1 expression levels, and the odds of T2DM.

A genetic variation in the fat mass- and obesity-associated gene is associated with obesity and newly diagnosed type 2 diabetes in a Chinese population

Recently, a genome‐wide association study identified a strong association between the fat mass‐ and obesity‐associated rs9939609 single nucleotide polymorphism (SNP) and the risk of obesity in European population. However, the results in Chinese population were reported to be contradictory. Therefore, our aim was to examine whether this SNP is associated with obesity and newly diagnosed type 2 diabetes (T2D) in Chinese population.

Association between C-reactive protein and pre-diabetic status in a Chinese Han clinical population.

Background C‐reactive protein (CRP) has been showed to be associated with type 2 diabetes mellitus, but whether CRP underlies glucose disorders in Asian people is still unclear, for they have much lower body mass index (BMI) levels than these Westerns in previous studies.

Influence of Vitamin E Supplementation on Glycaemic Control: A Meta-Analysis of Randomised Controlled Trials

Observational studies have revealed that higher serum vitamin E concentrations and increased vitamin E intake and vitamin E supplementation are associated with beneficial effects on glycaemic control in type 2 diabetes mellitus (T2DM). However, whether vitamin E supplementation exerts a definitive effect on glycaemic control remains unclear. This article involves a meta-analysis of randomised controlled trials of vitamin E to better characterise its impact on HbA1c, fasting glucose and fasting insulin. PubMed, EMBASE and the Cochrane Library were electronically searched from the earliest possible date through April 2013 for all relevant studies. Weighted mean difference (WMD) was calculated for net changes using fixed-effects or random-effects models. Standard methods for assessing statistical heterogeneity and publication bias were used. Fourteen randomised controlled trials involving individual data on 714 subjects were collected in this meta-analysis. Increased vitamin E supplementation did not result in significant benefits in glycaemic control as measured by reductions in HbA1c, fasting glucose and fasting insulin. Subgroup analyses revealed a significant reduction in HbA1c (−0.58%, 95% CI −0.83 to −0.34) and fasting insulin (−9.0 pmol/l, 95% CI −15.90 to −2.10) compared with controls in patients with low baseline vitamin E status. Subgroup analyses also demonstrated that the outcomes may have been influenced by the vitamin E dosage, study duration, ethnic group, serum HbA1c concentration, and fasting glucose control status. In conclusion, there is currently insufficient evidence to support a potential beneficial effect of vitamin E supplementation on improvements of HbA1c and fasting glucose and insulin concentrations in subjects with T2DM.

Plasma Heme Oxygenase-1 Concentration in Relation to Impaired Glucose Regulation in a Non-Diabetic Chinese Population

Background Our previous study has recently shown that plasma heme oxygenase-1 (HO-1), a stress-responsive protein, is elevated in individuals with type 2 diabetes. The current study aimed to examine the association between plasma HO-1 concentration and impaired glucose regulation (IGR) in non-diabetic individuals. Methods We conducted a case-control study including a total of 865 subjects (262 IGR individuals and 603 healthy controls) in a Chinese population. Basic characteristics were collected by questionnaire and standardized anthropometric measurements. Plasma HO-1 concentration was determined by ELISA. Results Plasma HO-1 concentration was significantly increased in IGR individuals compared with healthy controls (1.34 (0.81–2.29) ng/ml vs 0.98 (0.56–1.55) ng/ml, P<0.001). After adjustment for age, sex, and BMI, the ORs for IGR in the highest quartile of plasma HO-1 concentrations, compared with the lowest, was 3.42 (95% CI 2.11–5.54; P for trend <0.001). The trend remained significant even after additional adjustment for smoking, alcohol drinking, hypertension, family history of diabetes, lipid profiles and C-reactive protein. In the receiver-operating characteristic curve analysis, addition of plasma HO-1 concentration to a model with known risk factors yielded significantly improved discriminative value for IGR (area under the curves 0.75 (95% CI 0.71–0.78) vs. 0.72 (95% CI 0.69–0.76); P for difference = 0.026). Conclusions Elevated plasma HO-1 concentration is significantly associated with increased ORs for IGR. However, its clinical utility should be validated in further studies, especially in prospective cohort studies.

The changes of leukocyte telomere length and telomerase activity after sitagliptin intervention in newly diagnosed type 2 diabetes

In recent years, increasing evidence suggests a potential importance of telomere biology in type 2 diabetes. The aim of this study was to determine whether sitagliptin, a medicine generally used in diabetes, can influence the telomere and telomerase in newly diagnosed type 2 diabetic patients.

Glargine insulin/gliclazide MR combination therapy is more effective than premixed insulin monotherapy in Chinese patients with type 2 diabetes inadequately controlled on oral antidiabetic drugs

The aim of this study is to compare the efficacy and safety of once‐daily insulin glargine plus gliclazide modified release combination therapy versus twice‐daily premixed insulin monotherapy in Chinese type 2 diabetic patients insufficiently controlled by oral antidiabetic agents.

Pioglitazone ameliorates Aβ42 deposition in rats with diet-induced insulin resistance associated with AKT/GSK3β activation

Pioglitazone may have potential benefits as an alternative therapeutic treatment for patients with Alzheimers disease (AD), particularly in individuals that also have comorbid diabetes; however, the mechanisms of action remain unclear. The present study aimed to explore the effects of pioglitazone on amyloid β, isoform 42 (Aβ42) deposition in rats with diet-induced insulin resistance (IR). Diet-induced IR model rats were established in the presence or absence of pioglitazone. Plasma glucose and insulin levels, and cerebrospinal fluid insulin levels were measured; in addition, hippocampal tissues were collected for immunohistochemical analysis of Aβ42 expression. The levels of insulin-degrading enzyme (IDE) and peroxisome proliferator-activated receptor γ (PPARγ) mRNA and protein expression were analyzed by reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. In addition, the activation of glycogen synthase kinase 3β (GSK3β) induced by phosphatidylinositol 3-kinase (PI3K) /protein kinase B (AKT) signaling was detected by western blotting. Results from the present study demonstrated that pioglitazone may enhance peripheral and brain insulin sensitivity in diet-induced IR model rats. Treatment with pioglitazone ameliorated Aβ42 deposition in the hippocampus by increasing IDE and PPARγ expression. Notably, activation of the PI3K/AKT/GSK3β pathway was also demonstrated to serve a role in pioglitazone-induced Aβ42 degradation, which was abrogated by the PPARγ antagonist GW9662. Results from the present study indicated that pioglitazone may improve insulin sensitivity and ameliorate Aβ42 accumulation in rats with diet-induced IR by regulating AKT/GSK3β activation, suggesting that pioglitazone may be a promising drug for AD treatment.

Correlation of liver enzymes with diabetes and pre-diabetes in middle-aged rural population in China

The survey aimed to explore the association of liver transaminases with the prevalence of type 2 diabetes mellitus (T2DM) and pre-diabetes (pre-DM) in the middle-aged rural population in China. A cross-sectional study was conducted in 10 800 middle-aged subjects who lived in rural area of central China. The 75-g oral glucose-tolerance test (OGTT) was performed. Participants were asked to complete physical examination and standard questionnaire. The serum liver transaminases (ALT and GGT), HbA1C and serum lipids were measured. In middle-aged rural population, the prevalence of impaired fasting glucose (IFG), impaired glucose tolerance (IGT), impaired fasting glucose combined with impaired glucose tolerance (IFG+IGT) and DM was 4.0%, 11.8%, 2.6% and 10.0%, respectively. Some measurements were higher in males than in females, such as waist hip ratio (WHR), blood pressure, fasting blood glucose (FBG), high density lipoprotein-cholesterol (HDL-C), and liver enzymes (ALT and GGT). Further, we found that elevated serum GGT and ALT levels were significantly positively correlated with the prevalence of DM, independent of central obesity, serum lipid and insulin resistance (IR) in both genders. However, the correlation of GGT and ALT with pre-DM was determined by genders and characteristics of liver enzymes. Higher serum GGT was indicative of IGT in both genders. The association of serum ALT with pre-DM was significant only in female IGT group. In conclusion, our present survey shows both serum GGT and ALT are positively associated with DM, independent of the cardiovascular risk factors in both genders.SummaryThe survey aimed to explore the association of liver transaminases with the prevalence of type 2 diabetes mellitus (T2DM) and pre-diabetes (pre-DM) in the middle-aged rural population in China. A cross-sectional study was conducted in 10 800 middle-aged subjects who lived in rural area of central China. The 75-g oral glucose-tolerance test (OGTT) was performed. Participants were asked to complete physical examination and standard questionnaire. The serum liver transaminases (ALT and GGT), HbA1C and serum lipids were measured. In middle-aged rural population, the prevalence of impaired fasting glucose (IFG), impaired glucose tolerance (IGT), impaired fasting glucose combined with impaired glucose tolerance (IFG+IGT) and DM was 4.0%, 11.8%, 2.6% and 10.0%, respectively. Some measurements were higher in males than in females, such as waist hip ratio (WHR), blood pressure, fasting blood glucose (FBG), high density lipoprotein-cholesterol (HDL-C), and liver enzymes (ALT and GGT). Further, we found that elevated serum GGT and ALT levels were significantly positively correlated with the prevalence of DM, independent of central obesity, serum lipid and insulin resistance (IR) in both genders. However, the correlation of GGT and ALT with pre-DM was determined by genders and characteristics of liver enzymes. Higher serum GGT was indicative of IGT in both genders. The association of serum ALT with pre-DM was significant only in female IGT group. In conclusion, our present survey shows both serum GGT and ALT are positively associated with DM, independent of the cardiovascular risk factors in both genders.