Circulating interleukin-1β and interleukin-6 concentrations are closely associated with γ-glutamyltranspeptidase activity in middle-aged Japanese men without obvious cardiovascular diseases

Interleukin (IL)-1β and IL-6 expressions are known to be induced by oxidant stress. In the present study, we examined the relationships between these interleukins and the activity of γ-glutamyltranspeptidase (γ-GTP), which was recently reported as a source of oxidant stress production, in the circulating blood of middle-aged Japanese men without obvious cardiovascular diseases. We conducted a cross-sectional study of 317 Japanese men without obvious cardiovascular diseases aged 40 to 69 years (mean ± SD, 58.6 ± 7.6 years) who participated in health checkups in Japan. We analyzed their clinical parameters in serum, lifestyle factors, and plasma IL-1β and IL-6 concentrations. We compared the relationships between these interleukin concentrations and the clinical parameters and lifestyle factors by Spearman correlation coefficients. Stepwise multiple linear regression analyses for interleukins based on the other parameters and γ-GTP, which were classified into 3 groups according to the concentrations, were performed. Interleukin-1β and IL-6 concentrations were closely associated with γ-GTP activity but less associated with alanine aminotransferase and aspartate aminotransferase activities by Spearman correlation coefficients. Stepwise multiple linear regression analyses showed that γ-GTP activity was the explanatory variable for elevated IL-1β and IL-6 concentrations. As natural logarithms, the IL-1β and IL-6 concentrations were estimated to be 1.734- and 1.157-fold higher, respectively, in subjects with high γ-GTP activity ranges than in subjects with a low γ-GTP activity range. The present results show that circulating IL-1β and IL-6 concentrations are strongly and independently associated with γ-GTP activity in middle-aged Japanese men without obvious cardiovascular diseases.     

Gly482Ser polymorphism in the peroxisome proliferator-activated receptor γ coactivator-1α gene is associated with oxidative stress and abdominal obesity

The objective of the study was to o investigate the relationship of the Gly482Ser (G482S) polymorphism in the peroxisome proliferator-activated receptor γ coactivator-1α (PPARGC1A) gene and type 2 diabetes mellitus (T2DM), obesity, and oxidative status in Chinese adults. We enrolled 276 T2DM patients and 1049 nondiabetic subjects aged at least 35 years. The G482S variant was detected using polymerase chain reaction and restriction enzyme digestion. The levels of thiobarbituric acid reactive substance, an indicator of lipid peroxidation, were measured in plasma samples. The homeostasis model assessment-estimated insulin resistance (HOMA-IR) index was determined for nondiabetic subjects. P values were adjusted for age, sex, and body mass index by using a generalized linear model. In this series, there was no association between G482S polymorphism and T2DM and obesity (body mass index >25 kg/m²). However, the plasma fasting insulin levels and HOMA-IR indices were significantly higher in nondiabetic subjects harboring the variant (S/S) genotype than in those with the heterozygous (G/S) genotype. With regard to the effect of the different genotypes on body fat distribution, overweight nondiabetic subjects harboring the S/S or G/S genotype had a significantly higher waist-to-hip ratio than those with the wild-type (G/G) genotype. Furthermore, subjects with the S/S genotype had significantly higher serum thiobarbituric acid reactive substance levels than those with the G/G genotype; the diabetic group mainly contributed to this significant association (P < .001). In overweight, nondiabetic Chinese adults, G482S polymorphism in the PPARGC1A gene is associated with hyperinsulinemia, HOMA-IR indices, and abdominal obesity. Furthermore, in hyperglycemia, the S482 allele is related to increased oxidative stress.     

Changes in body weight are significantly associated with changes in fasting plasma glucose and HDL cholesterol in Japanese men without abdominal obesity (waist circumference < 85 cm)

The aims are to examine whether changes in body weight (dBW) are associated with changes in cardiovascular risk factors in Japanese men without abdominal obesity (waist circumference (WC) < 85 cm) and which anthropometric index, dBW or changes in WC (dWC), is more strongly associated with changes in cardiovascular risk factors in men without abdominal obesity. It is a retrospective study in 692 Japanese men without abdominal obesity who took annual health screening tests consecutively over one year. Standardized linear regression coefficients (SRCs) of dBW and dWC were calculated for changes in systolic blood pressure (dSBP), diastolic blood pressure (dDBP), fasting plasma glucose (dFPG), triglycerides (dTG), HDL cholesterol (dHDL), and high-sensitivity C-reactive protein (dCRP). The SRCs of dBW for dFPG and dHDL were significant in all men and in men with each risk factor corresponding to the component of metabolic syndrome (MetS). The SRCs of dWC for dTG and dCRP were significant in all men but not in men with each risk factor corresponding to the MetS component. In conclusions, dBW were significantly associated with dFPG and dHDL in Japanese men without abdominal obesity. Therefore, abdominal obesity should not be considered as a necessary component of MetS in Japanese men. dBW may be more useful than dWC as a marker of changes in cardiovascular risk factors in lifestyle intervention programs.     

Novel CYP17A1 mutation in a Japanese patient with combined 17α-hydroxylase/17,20-lyase deficiency

Combined 17α-hydroxylase/17,20-lyase deficiency is caused by a defect of P450c17 that catalyzes both 17α-hydroxylase and 17,20-lyase reactions in adrenal glands and gonads. In the present study, we analyzed the CYP17A1 gene in a Japanese girl with 17α-hydroxylase/17,20-lyase deficiency. The patient was referred to us for clitoromegaly at the age of 3 years. The karyotype was 46,XY. The patient was diagnosed as having 17α-hydroxylase/17,20-lyase deficiency based on the clinical and laboratory findings. Analysis of the CYP17A1 gene revealed a compound heterozygous mutation. One mutation was a deletion of codon 53 or 54 encoding Phe (TTC) in exon 1 (ΔF54) on a maternal allele, which has been previously shown to partially abolish both 17α-hydroxylase and 17,20-lyase activities. The other was a novel missense mutation resulting in a substitution of Asn (AAC) for His (CAC) at codon 373 in exon 6 (H373N) on a paternal allele. Functional expression study demonstrated that the H373N mutation almost completely eliminates enzymatic activity. Previous studies have demonstrated that replacement of histidine by leucine at position 373 causes complete loss of both 17α-hydroxylase and 17,20-lyase activities with a defect in heme binding due to a global alteration of P450c17 structure, indicating the importance of H373 for P450c17 structure and function. Together, these results indicate that the patient is a compound heterozygote for the ΔF54 and H383N mutations and that these mutations inactivate both 17α-hydroxylase and 17,20-lyase activities and give rise to clinically manifest combined 17α-hydroxylase/17,20-lyase deficiency.     

Plasma concentrations of soluble IL-2 receptor α (CD25) are increased in type 1 diabetes and associated with reduced C-peptide levels in young patients

Aims/hypothesis

Type 1 diabetes is a common autoimmune disease that has genetic and environmental determinants. Variations within the IL2 and IL2RA (also known as CD25) gene regions are associated with disease risk, and variation in expression or function of these proteins is likely to be causal. We aimed to investigate if circulating concentrations of the soluble form of CD25, sCD25, an established marker of immune activation and inflammation, were increased in individuals with type 1 diabetes and if this was associated with the concentration of C-peptide, a measure of insulin production that reflects the degree of autoimmune destruction of the insulin-producing beta cells.

Methods

We used immunoassays to measure sCD25 and C-peptide in peripheral blood plasma from patient and control samples.

Results

We identified that sCD25 was increased in patients with type 1 diabetes compared with controls and replicated this result in an independent set of 86 adult patient and 80 age-matched control samples (p?=?1.17?×?10^?3). In 230 patients under 20 years of age, with median duration-of-disease of 6.1 years, concentrations of sCD25 were negatively associated with C-peptide concentrations (p?=?4.8?×?10^?3).

Conclusions/interpretation

The 25% increase in sCD25 in patients, alongside the inverse association between sCD25 and C-peptide, probably reflect the adverse effects of an on-going, actively autoimmune and inflammatory immune system on beta cell function in patients.     

Decreased serum interleukin-17 and increased transforming growth factor-β levels in subjects with metabolic syndrome (Chennai Urban Rural Epidemiology Study-95)

The term metabolic syndrome (MS) refers to a conglomeration of many metabolic disorders. Recent studies suggest that inflammation plays a vital role in MS. There are however no data available on the recently characterized novel T-cell-derived cytokine interleukin (IL)-17 in MS; studies on the anti-inflammatory cytokine transforming growth factor (TGF)-β are also limited. The aim of the study was to look at IL-17 and TGF-β levels in subjects with and without MS. The study subjects were recruited from the Chennai Urban Rural Epidemiology Study (CURES), a population-based study in Chennai (formerly Madras) in southern India. Group 1 consisted of subjects without MS (non-MS) (n = 98) and group 2 consisted of subjects with MS (n = 156). MS was defined using the National Cholesterol Education Program Adult Treatment Panel III criteria modified for waist, according to the World Health Organization Asia Pacific guidelines. Serum IL-17 and TGF-β levels were estimated by enzyme-linked immunosorbent assay. Interleukin-17 levels were decreased (P < .001) and TGF-β levels (P < .001) were increased in subjects with MS compared to those without. With an increase in the number of metabolic risk factors, the IL-17 levels showed a decline, whereas the TGF-β levels showed an increase (P < .001). With respect to individual components of MS, TGF-β and IL-17 showed a significant association with blood pressure and blood glucose even after adjusting for age and sex. We report that IL-17 levels are decreased, whereas TGF-β levels are increased, among Asian Indians with MS.     

Visceral fat decreased by long-term interdisciplinary lifestyle therapy correlated positively with interleukin-6 and tumor necrosis factor-α and negatively with adiponectin levels in obese adolescents

The purpose of this study was to assess the level of cytokine expression in correlation with visceral and subcutaneous fat in obese adolescents admitted to long-term interdisciplinary weight loss therapy. The study was a longitudinal clinical intervention of interdisciplinary therapy. Adolescents (18, aged 15-19 years) with body mass indexes greater than the 95th percentile were admitted and evaluated at baseline and again after 1 year of interdisciplinary therapy. Visceral and subcutaneous fat was analyzed by ultrasonography. Blood samples were collected to analyze tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10), and adiponectin concentrations that were measured by enzyme-linked immunosorbent assay. The most important finding in the present investigation is that the long-term interdisciplinary lifestyle therapy decreased visceral fat. Positive correlations between IL-6 levels and visceral fat (r = 0.42, P < .02) and TNF-α levels and visceral fat (r = 0.40, P < .05) were observed. Negative correlations between TNF-α levels and subcutaneous fat (r = −0.46, P < .01) and adiponectin levels and subcutaneous fat (r = −0.43, P < .03) were also observed. In addition, we found a positive correlation between TNF-α levels and the visceral to subcutaneous fat ratio (r = 0.42, P < .02) and a negative correlation between adiponectin level and the visceral to subcutaneous fat ratio (r = −0.69, P < .001). Despite the limitation of sample size, our results indicate that the observed massive weight loss (mainly visceral fat) was highly correlated with a decreased inflammatory state, suggesting that the interdisciplinary therapy was effective in decreasing inflammatory markers.     

Do HbA1c levels and the self-monitoring of blood glucose levels adequately reflect glycaemic control during pregnancy in women with type 1 diabetes mellitus?

Aims/hypothesis

Pregnancies of women with type 1 diabetes mellitus are associated with maternal and perinatal complications. These complication rates remain elevated despite achievement of the treatment goals described in the widely used guidelines of the American Diabetes Association (i.e. HbA₁c level ≤7.0%). Against this background, we sought to answer two questions: (1) are HbA₁c levels within 1% above normal appropriate in pregnant women with type 1 diabetes or should treatment be aimed at normal HbA₁c levels; and (2) how many self-monitored blood glucose (SMBG) levels are needed per day to obtain an adequate image of glycaemic control in pregnant women with type 1 diabetes?

Materials and methods

We asked 43 pregnant women with type 1 diabetes to use the Continuous Glucose Monitoring System (CGMS) once in each trimester of pregnancy, while continuing their SMBG measurements. Glucose levels measured with the CGMS were compared between patients with HbA₁c levels of 4.0–6.0%, 6.0–7.0% and >7.0%. Self-monitored glucose levels and those measured with CGMS were compared between patients with four or five, six to nine and ten or more SMBG determinations daily.

Results

In patients with HbA₁c levels ≤6.0%, the glucose levels obtained by CGMS were significantly better than in patients with HbA₁c levels >6.0%. In women with HbA₁c levels 6.0–7.0% and >7.0%, these levels did not differ. The detection rate of hyper- and hypoglycaemic episodes was significantly higher in patients with ten or more SMBG determinations daily than in patients with fewer than ten.

Conclusions/interpretation

Treatment of diabetes in pregnant women should be aimed at achieving HbA₁c levels within the normal range, i.e. ≤6.0%. A minimum of ten SMBG determinations daily is necessary to obtain adequate information of all daily glucose fluctuations.     

Plasma triglyceride levels and body mass index values are the most important determinants of preβ-1 HDL concentrations in patients with various types of primary dyslipidemia

ObjectiveExperimental studies have shown that the preβ-1 subclass of high-density lipoprotein particles (preβ-1 HDL) may play an important role in the reverse cholesterol transport pathway as the initial acceptors of cellular cholesterol. The aim of the present study was the direct comparison of preβ-1 HDL values in individuals with various types of primary dyslipidemias.MethodsFour hundred and eighty-six unrelated individuals were included in the study. According to their lipid values study participants were subdivided into four groups: control group (n = 206), type IIA dyslipidemia group (n = 148), type IIB dyslipidemia group (n = 49) and type IV dyslipidemia group (n = 83).ResultsAll dyslipidemic patients displayed higher concentrations of preβ-1 HDL compared to control individuals. However, patients with dyslipidemias characterized by an abnormal catabolism of triglyceride-rich lipoproteins (such as dyslipidemias of type IIB and IV) tend to have higher preβ-1 HDL values compared to patients with hypercholesterolemia, and this increase is proportional to the degree of hypertriglyceridemia. In addition, patients with metabolic syndrome exhibited significantly higher levels of preβ-1 HDL compared to individuals that do not fulfill the criteria for the diagnosis of this syndrome. Multiple regression analysis revealed that serum triglyceride concentrations and body mass index (BMI) values were the most important determinants of preβ-1 HDL levels in our population.ConclusionAll dyslipidemic patients exhibit increased preβ-1 HDL concentrations as compared to normolipidemic individuals. Whether this increase represents a defensive mechanism against atherosclerosis or it is indicative of impaired maturation of HDL particles and thus of a defective reverse cholesterol transport mechanism remains to be established.     

Role of γ melanocyte-stimulating hormone-renal melanocortin 3 receptor system in blood pressure regulation in salt-resistant and salt-sensitive rats

Melanocortin 3 receptor (MC3-R) has high affinity and specificity to γ melanocyte-stimulating hormone (γMSH), a natriuretic peptide involved in regulation of blood pressure (BP) and sodium excretion. Recent studies showing increased MC3-R expression and elevated plasma γMSH in normal rats fed a high-salt diet support the role of this system in sodium homeostasis. We hypothesized that dysregulation of MC3-R response to dietary salt may contribute to salt retention and BP elevation in salt-sensitive hypertension. We examined renal MC3-R expression, plasma γMSH concentration, and response to MC3-R agonist and antagonist in Dahl salt-sensitive (DSS) and Dahl salt-resistant (DSR) rats fed high-salt (8%) or low-salt (0.07%) diets for 3 weeks. Consumption of high-salt diet significantly increased BP in the DSS but not the DSR group. High-salt diet led to a 5-fold increase in plasma γMSH and a 2-fold increase in renal MC3-R in DSR rats. Plasma γMSH and renal MC3-R abundance in DSS rats were maximally elevated on low-salt diet and remained unchanged on high-salt diet. Administration of MC3-R agonist melanotan II significantly lowered BP and raised fractional Na excretion in the DSR but not the DSS rats consuming high-salt diet. In contrast, MC3-R antagonist SHU9119 significantly raised BP and lowered fractional Na excretion in both groups. Thus, the data suggest that γMSH-renal MC3-R pathway is activated and appears to be biologically functional in the DSS rats.     

Risk factors for 28-day mortality in elderly patients with extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae bacteremia

Gram-negative bacteremia is common in elderly patients and, compared with younger patients, mortality rates in bacteremic elderly patients are high. ESBL-producing organisms were one of the most important risk factors associated with mortality. In addition, older age is one of risk factors for colonization or infection with ESBL-producing organisms. We conducted a retrospective cohort study to evaluate risk factors of all-cause 28-day mortality in elderly patients with ESBL-producing Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) bacteremia. Patients aged 65 years or older, who had one or more blood cultures positive for E. coli and K. pneumoniae and who were hospitalized between January 2006 and December 2010 at a tertiary-care teaching hospital, were included. 191 bacteremic elderly patients were eligible for the study. The all-cause 28-day mortality rate was 24.6% (47/191). In multivariate analysis, prior antimicrobial therapy (p = 0.014) and an elevated SOFA score (p < 0.001) were independent risk factors for increased mortality, while urinary tract infection (UTI) was an independent determinant for non-mortality (p = 0.011). In the current study, prior antimicrobial therapy within 30 days, an elevated SOFA score and nonurinary source of infection were significantly associated with adverse outcomes in elderly patients with ESBL-producing gram-negative bacteremia.     

The association of tumor necrosis factor α receptor 2 and tumor necrosis factor α with insulin resistance and the influence of adipose tissue biomarkers in humans

Tumor necrosis factor α (TNFα) is a proinflammatory adipokine hypothesized to link obesity with insulin resistance. Functional studies suggest that TNFα acts through pathways involving adipokines and fatty acids to induce insulin resistance. We tested the hypothesis that the association of measures of TNFα activity with insulin resistance is independent of obesity and adipose tissue biomarkers. We analyzed data from 2131 participants (without diabetes) of the Framingham Offspring Study examination 7. The outcome of interest was insulin resistance, measured using the homeostasis model assessment (HOMA-IR). Tumor necrosis factor α activity was measured by plasma tumor necrosis factor α receptor 2 (TNFr2) or TNFα; possible confounders included adipose tissue biomarkers (plasma adiponectin, resistin, and triglycerides). We used multivariable age- and sex-adjusted linear regression analyses to adjust for waist circumference and for biomarkers individually and simultaneously, and in biomarker-stratified (above and below median) models. We found that TNFr2 was positively associated with HOMA-IR (r = 0.21, P < .0001). In age- and sex-adjusted model, for each increase of 1 standard deviation of TNFr2 (SD = 746 pg/mL), the log (HOMA-IR) value was increased by 0.11 units (P < .0001). Adjustment for waist circumference reduced the TNFr2 β-coefficient (by about 45%), but the association between TNFr2 and HOMA-IR remained significant (P < .0001). Tumor necrosis factor α receptor 2 was still associated to HOMA-IR after adding adiponectin, resistin, and triglycerides (individually and simultaneously). We found similar associations with plasma levels of TNFα. We conclude that, in a representative community sample, measures of TNFα activity are associated with insulin resistance, even after accounting for central adiposity and other adipose tissue biomarkers.     

Common variants at the GCK, GCKR, G6PC2–ABCB11 and MTNR1B loci are associated with fasting glucose in two Asian populations

Aims/hypothesis

To test fasting glucose association at four loci recently identified or verified by genome-wide association (GWA) studies of European populations, we performed a replication study in two Asian populations.

Methods

We genotyped five common variants previously reported in Europeans: rs1799884 (GCK), rs780094 (GCKR), rs560887 (G6PC2–ABCB11) and both rs1387153 and rs10830963 (MTNR1B) in the general Japanese (n?=?4,813) and Sri Lankan (n?=?2,319) populations. To identify novel variants, we further examined genetic associations near each locus by using GWA scan data on 776 non-diabetic Japanese samples.

Results

Fasting glucose association was replicated for the five single nucleotide polymorphisms (SNPs) at p?<?0.05 (one-tailed test) in South Asians (Sri Lankan) as well as in East Asians (Japanese). In fine-mapping by GWA scan data, we identified in the G6PC2–ABCB11 region a novel SNP, rs3755157, with significant association in Japanese (p?=?2.6?×?10^-8) and Sri Lankan (p?=?0.001) populations. The strength of association was more prominent at rs3755157 than that of the original SNP rs560887, with allelic heterogeneity detected between the SNPs. On analysing the cumulative effect of associated SNPs, we found the per-allele gradients (β?=?0.055 and 0.069 mmol/l in Japanese and Sri Lankans, respectively) to be almost equivalent to those reported in Europeans.

Conclusions/interpretation

Fasting glucose association at four tested loci was proven to be replicable across ethnic groups. Despite this overall consistency, ethnic diversity in the pattern and strength of linkage disequilibrium certainly exists and can help to appreciably reduce potential causal variants after GWA studies.     

The Pro12Ala polymorphism of the PPARγ2 gene is associated with hepatic glucose uptake during hyperinsulinemia in subjects with type 2 diabetes mellitus

The Ala12 allele of the peroxisome proliferator-activated receptor γ gene (PPARG2) has been associated with reduced risk of type 2 diabetes mellitus (T2DM) and increased whole-body and skeletal muscle insulin sensitivity in nondiabetic subjects. The effect of the Pro12Ala polymorphism on tissue specific insulin sensitivity in subjects with T2DM has not been previously investigated. We studied the effect of the Pro12Ala polymorphism on the rates of whole-body, skeletal muscle, and subcutaneous adipose tissue glucose uptake (GU) in T2DM subjects, and the rates of hepatic GU in nondiabetic and T2DM subjects during hyperinsulinemia. Our study included 105 T2DM subjects whose whole-body, skeletal muscle, subcutaneous adipose tissue, and hepatic GUs were measured using ¹⁸F-fluorodeoxyglucose and positron emission tomography during the hyperinsulinemic euglycemic clamp. Hepatic GU was also measured in 68 nondiabetic subjects. In obese (body mass index ≥27 kg/m²) subjects with T2DM, the rate of hepatic GU was 28% lower in subjects with the Pro12Pro genotype than in carriers of the Ala12 allele (P = .001); and a similar trend was observed in nondiabetic obese subjects (P = .137). No effect of the Pro12Ala polymorphism on the rates of whole-body, skeletal muscle, or subcutaneous adipose tissue GU was observed in T2DM subjects. We conclude that the Ala12 allele of PPARG2 is associated with higher hepatic GU in obese subjects with T2DM.     

DNA methylation markers associated with type 2 diabetes,fasting glucose and HbA<Subscript>1c</Subscript> levels: a systematic review and replication in a case–control sample of the Lifelines study

Aims/hypothesis

Epigenetic mechanisms may play an important role in the aetiology of type 2 diabetes. Recent epigenome-wide association studies (EWASs) identified several DNA methylation markers associated with type 2 diabetes, fasting glucose and HbA_1c levels. Here we present a systematic review of these studies and attempt to replicate the CpG sites (CpGs) with the most significant associations from these EWASs in a case–control sample of the Lifelines study.

Methods

We performed a systematic literature search in PubMed and EMBASE for EWASs to test the association between DNA methylation and type 2 diabetes and/or glycaemic traits and reviewed the search results. For replication purposes we selected 100 unique CpGs identified in peripheral blood, pancreas, adipose tissue and liver from 15 EWASs, using study-specific Bonferroni-corrected significance thresholds. Methylation data (Illumina 450K array) in whole blood from 100 type 2 diabetic individuals and 100 control individuals from the Lifelines study were available. Multivariate linear models were used to examine the associations of the specific CpGs with type 2 diabetes and glycaemic traits.

Results

From the 52 CpGs identified in blood and selected for replication, 15 CpGs showed nominally significant associations with type 2 diabetes in the Lifelines sample (p < 0.05). The results for five CpGs (in ABCG1, LOXL2, TXNIP, SLC1A5 and SREBF1) remained significant after a stringent multiple-testing correction (changes in methylation from ?3% up to 3.6%, p < 0.0009). All associations were directionally consistent with the original EWAS results. None of the selected CpGs from the tissue-specific EWASs were replicated in our methylation data from whole blood. We were also unable to replicate any of the CpGs associated with HbA_1c levels in the healthy control individuals of our sample, while two CpGs (in ABCG1 and CCDC57) for fasting glucose were replicated at a nominal significance level (p < 0.05).

Conclusions/interpretation

A number of differentially methylated CpGs reported to be associated with type 2 diabetes in the EWAS literature were replicated in blood and show promise for clinical use as disease biomarkers. However, more prospective studies are needed to support the robustness of these findings.