Interleukin 6, adiponectin, leptin, and insulin resistance in nonobese Japanese type 2 diabetic patients

A Study of Correlation of Adiponectin Levels in Metabolic Syndrome

Introduction: Metabolic syndrome (MetS), also known as insulin resistance syndrome, is described as a cluster of cardiometabolic symptoms such as high blood pressure, elevated fasting glucose, or insulin resistance. MetS is one of the most serious public health problems being faced globally. The purpose of the current investigation was to determine its prevalence, as well as the relationship between blood adiponectin levels and the development of MetS. Materials and Methods: This observational cross-sectional hospital-based study was performed in the Department of General Medicine, School of Medical Sciences and Research, Sharda Hospital, Greater Noida, Uttar Pradesh, India, from January 2019–June 2020. Sixty patients attending the medicine out- or inpatient department, who confirmed consent, and fit into the International Diabetes Federation (IDF) inclusion criteria for MetS, were recruited for this study. The final sample size for this study was found to be 60, with a prevalence of 10%. This is the reason the study’s precision decreased to ±7.6%, implying that the precision of the end result may vary by ±7.6%. Results: Subjects without MetS were on average younger, had a lower BMI, and had a smaller waist circumference than those who had MetS, according to the findings. They also had lower blood pressure, pulse rate, and fasting plasma glucose levels than the people with MetS, and there were statistically significant variations in lipid profiles between those with and without MetS. In people who did not have MetS, the mean serum adiponectin concentration was 15.79±2.90 mg/mL, whereas the mean serum adiponectin concentration in people who did have MetS was 11.02±2.63 mg/mL (p<0.001). The levels of adiponectin were compared with the different components of MetS as defined by the IDF. The mean adiponectin concentrations in connection to the clinical characteristics of MetS are shown in Table 1 . The authors discovered that lower adiponectin levels were statistically significantly linked with the majority of the characteristics. In a multivariate analysis, the serum adiponectin content was found to be significantly inversely associated to systolic blood pressure (r=-0.262; p<0.050), BMI (r=-0.288; p<0.050), total cholesterol (r=-0.515; p<0.001), and low-density lipoprotein (r=-0.305; p<0.050) in the study participants. Conclusion: In conclusion, the present results suggest that circulating levels of adiponectin are reduced in the presence of MetS.

Evaluation of Serum Omentin-1, Vaspin, Leptin, Adiponectin Levels in Obese/Overweight Children and Their Relationship With Non-Alcoholic Fatty Liver Disease

To investigate adipokines (vaspin, omentin-1, adiponectin and leptin) and their correlation with hepatosteatosis degree in obese/overweight (O/O) children. We analyzed adipokine levels of 81 children (49 O/O, [body mass index (BMI) > 95^th] and 32 non-obese (BMI = 5-85^th) admitted to the pediatric outpatient clinic. Serum triglyceride, glucose, low density lipoprotein-cholesterol, total cholesterol, high density lipoprotein-cholesterol, alanine aminotransferase, aspartate aminotransferase (AST), insulin, HbA1c levels and leptin, omentin-1, vaspin, adiponectin levels were studied. O/O children with hepatosteatosis were divided into grades 1, 2 and 3 according to the degree of hepatosteatosis determined by ultrasonography. While AST (p = 0.001), triglyceride (p = 0.006), BMI percentile (p = 0.000), HOMA index (p = 0.002), systolic blood pressure (p = 0.02), leptin (p = 0.001), omentin-1 (p = 0.001), adiponectin (p = 0.001) levels were higher, vaspin level was lower (p = 0.008) in the (O/O) group compared to the controls. There was a positive correlation between HDL and vaspin, and a negative correlation between HDL and omentin-1 in the O/O group. Also it was observed that as the degree of hepatosteotosis increased, leptin (p = 0.004), omentin-1 (p = 0.001) levels were increased. There was no significant change in vaspin level (p = 0.128). The high levels of omentin-1, leptin and adiponectin have an association with the development of hepatosteatosis in O/O children.

Cultural and life style practices associated with low inflammatory physiology in Japanese adults

Japan is an exceptionally healthy East Asian country with extended longevity. In addition, the typical levels of several proinflammatory proteins, including both C-reactive protein (CRP) and interleukin-6 (IL-6), are often reported to be low when compared to American and European populations. This analysis determined if blood levels of CRP and IL-6 were associated with 4 cultural practices reflective of Japanese behavior and customs -- drinking tea, eating seafood, consuming vegetables, and partaking in relaxing baths regularly - among 382 adults living in Tokyo. Regression models controlled for demographic factors, adiposity (BMI), physical exercise, smoking, alcohol use, and chronic illness (e.g., diabetes). Consuming a Japanese diet was associated with significantly lower CRP and IL-6 levels. More frequent bathing was associated with lower IL-6, but not specifically predictive of low CRP. This study has confirmed prior evidence for low inflammatory activity in Japanese adults and its association with several behavioral practices common in Japan.

Metabolic Syndrome, Physical Activity, and Inflammation: A Cross-Sectional Analysis of 110 Circulating Biomarkers in Japanese Adults

BACKGROUND

Metabolic syndrome (MetS) is a systemic inflammatory state. Low physical activity (PA) could modify this patho-physiology or act as an independent contributor to inflammation. Previous studies of both conditions have identified altered levels of inflammation- and immune-related proteins based on limited sets of candidate markers.

METHODS

We investigated associations of MetS and low PA with circulating inflammation markers in a stratified random sample of Japanese adults (N = 774, mean age 60.7 years) within the Japan Public Health Center-based Prospective Study (JPHC) Cohort II. AHA/NHLBI criteria were used to define MetS (19%) and the bottom quartile of PA was considered low. 110 circulating biomarkers, including cytokines, chemokines, and soluble receptors were measured by multiplex bead-based and proximity-extension assays. Associations of MetS and low PA with marker quantiles were adjusted for each other and for age, sex, study site, cigarette smoking, alcohol consumption, and blood sample fasting state by ordinal logistic regression. P values were corrected for FDR.

RESULTS

MetS was significantly associated with levels of six markers: IL18R1 [odds ratio 2.37; 95% confidence interval (CI), 1.45-3.87], CRP (2.07; 95% CI, 1.48-2.90), SAP (2.08; 95% CI, 1.47-2.95), CCL19/MIP3β (2.06; 95% CI, 1.48-2.88), CXCL12/SDF1α+β (0.48; 95% CI, 0.32-0.65), and CCL28 (0.44; 95% CI, 0.27-0.71). Low PA had no significant marker associations.

CONCLUSIONS

Positively associated markers with MetS are mostly Th1 immune response-related and acute phase proteins, whereas negatively associated markers are generally Th2-related.

IMPACT

MetS is associated with a broad range of alterations in immune and inflammatory biomarkers that may contribute to risks of various chronic diseases, independent of low PA.

Correlation between PAI-1, leptin and ferritin with HOMA in HIV/AIDS patients

BACKGROUND

Data about correlation of interleukins (IL-1 α, IL-1 β, IFN γ, IL-2, IL-4, IL-6, IL-8, IL-10), adipocytokines (leptin, adiponectin, monocyte chemoattractant protein-1 (MCP-1), resistin, plasminogen activator inhibitor-1 (PAI-1), tumor necrosis factor alpha (TNFα), ferritin, C reactive protein (CRP) and vascular endothelial growth factor (VEGF) with homeostasis model assessment (HOMA) in HIV/AIDS patients are still limited. Therefore the aim of this study was to evaluate the possible correlations of serum levels of PAI-1, leptin and ferritin with HOMA in HIV/AIDS patients treated with combined antiretroviral therapy (cART).

METHODS

This cross-sectional study included 64 HIV/AIDS patients, all Caucasians, receiving cART at the HIV/AIDS Centre, Belgrade, Serbia. PAI-1, leptin, ferritin and insulin levels were measured using the Metabolic Syndrome Array I (Randox Laboratories Ltd., London, UK), while adiponectin and resistin levels were measured using Metabolic Syndrome Array II (Randox Laboratories Ltd., London, UK), interleukins (IL-1 α, IL-1 β, IFN γ, IL-2, IL-4, IL-6, IL-8, IL-10), MCP-1, TNF-α as well as VEGF was measured using Cytokine Array I (Randox Laboratories Ltd., London, UK). Insulin resistance was determined using the homeostasis model assessment index (HOMA). Multicollinearity of independent variables in multivariate model was analyzed using Variance Inflation Factor.

RESULTS

Correlation analysis revealed significant correlations between HOMA and waist circumference, body mass index, patients' age, number of cART combinations and triglycerides (p = 0.001, p = 0.001, p = 0.050, p = 0.044, p = 0.002, respectively). HOMA negatively correlated with levels of high density lipoprotein (HDL) (Rho = -0.282; p = 0.025). PAI-1 (Rho = 0.334; p= 0.007) and leptin (Rho = 0.492; p = 0.001) together with ferritin (Rho = 0.396, p = 0.001) positively and significantly correlated with HOMA. Levels of IL-1 α, IL-1 β, IFN γ, IL-2, IL-4, IL-6, IL-8, IL-10, adiponectin, MCP-1, resistin, TNF-α, CRP and VEGF did not significantly correlate with HOMA. Further, multiple logistic regression showed that there is a statistically significant correlation between PAI, leptin and ferritin with HOMA levels (p = 0.042; p < 0.001, p = 0.009).

CONCLUSIONS

We showed significant correlation between PAI-1, leptin and ferritin, independently of each other with HOMA, in HIV/AIDS patients on cART.

Circulating and Adipose Levels of Adipokines Associated With Insulin Sensitivity in Nonobese Subjects With Type 2 Diabetes

CONTEXT

The adipokines chemerin, dipeptidyl peptidase 4, and adiponectin influence insulin sensitivity. Whether their circulating levels and adipose secretion are altered in nonobese individuals with type 2 diabetes mellitus (T2DM) is unknown.

OBJECTIVE

The objective of this study was to investigate SC adipose secretion and serum levels of the three adipokines in relation to T2DM features.

DESIGN

Fourteen nonobese T2DM and 13 healthy men were investigated. Insulin sensitivity and glucose control were assessed by hyperinsulinemic euglycemic clamp, homeostasis model assessment, and glycated hemoglobin.

MAIN OUTCOME MEASURE

Association of circulating and adipose-secreted adipokines with fat cell volume and insulin sensitivity was measured.

PARTICIPANTS

Volunteers in an outpatient academic clinic participated.

RESULTS

Although adipose secretion was similar between the groups, serum chemerin was higher (70 ± 10 vs 50 ± 1 ng/ml; P = .005), adiponectin lower (4.7 ± 1.3 vs 6.8 ± 2.2 μg/ml; P = .005), and dipeptidyl peptidase 4 unaltered in T2DM. Serum adiponectin (r = 0.53; P = .005) and chemerin (r = -0.42; P = .03) correlated with adipose secreted levels. Secreted and circulating chemerin correlated positively with adipocyte volume (r > 0.40; P < .05), whereas serum adiponectin correlated negatively with this measure (r = -0.61; P = .001). Adiponectin serum half-life was decreased in T2DM (168 ± 24 vs 186 ± 18 minutes; P = .029) and correlated negatively with glycated hemoglobin (r = -0.45; P = .03) and adipocyte volume (r = -0.56; P < .003). Serum adiponectin (r = 0.57; P = .017) and chemerin (r = -0.52; P = .03) associated with clamp measures independently of T2DM diagnosis.

CONCLUSIONS

In nonobese men, circulating adiponectin and chemerin levels are altered in T2DM without changes in adipose secretion. Adipocyte volume is important for variations in serum chemerin and adiponectin and for serum clearance of adiponectin. In T2DM, poor glucose control also plays a role for adiponectin clearance.

MiR-19a regulates PTEN expression to mediate glycogen synthesis in hepatocytes

MiR-19a, a member of mir-17-92 microRNA clusters, has been demonstrated to promote cell proliferation and angiogenesis via regulating the PI3K/AKT pathway, the major insulin signaling pathway. However, whether miR-19a plays an important role in glycogen synthesis in hepatocytes remains unknown. Here, we define the impact of miR-19a on glycogen synthesis and IL-6-induced reduced glycogenesis in hepatocytes and its underlying mechanisms. Our studies indicate that miR-19a was down-regulated in the livers of db/db mice and mice injected with IL-6, as well as mouse NCTC 1469 hepatocytes and HEP 1–6 hepatocytes treated by IL-6. We found that over-expression of miR-19a in NCTC 1469 cells and HEP 1–6 cells led to increased activation of the AKT/GSK pathway and synthesis of glycogen, whereas down-regulation of miR-19a impaired AKT/GSK phosphorylation and glycogenesis. Over-expression of miR-19a ameliorated IL-6-induced reduced glycogen synthesis in hepatocytes. Moreover, we identified PTEN as the target of miR-19a by a luciferase assay. Down-regulation of PTEN rescued the effects of miR-19a suppression on the activation of the AKT/GSK pathway and improved glycogenesis in NTC 1469 cells. These findings show for the first time that miR-19a might activate the AKT/GSK pathway and glycogenesis via down-regulation of PTEN expression.

Circulating TNF receptor 2 is associated with the development of chronic kidney disease in non-obese Japanese patients with type 2 diabetes

AIMS

Chronic low-grade inflammation and/or obesity are suggested to induce chronic kidney disease (CKD) in patients with type 2 diabetes. This cross-sectional study was performed to investigate the relationship between inflammatory biomarkers and CKD in non-obese patients with type 2 diabetes.

METHODS

106 non-obese Japanese patients with type 2 diabetes were recruited for the measurement of GFR, TNF, HMW adiponectin, leptin, hsCRP and some variables including urinary albumin. BMI, serum creatinine, and urinary albumin levels were 22.2 ± 0.2 kg/m(2) (17.1-24.9 kg/m(2)), 0.76 ± 0.02 mg/dl (0.39-1.38 mg/dl), 40.4 ± 4.3mg/gCr (1.6-195.0mg/gCr), respectively. They were stratified into two groups based on the value of eGFR: low eGFR (eGFR<60 ml/min/1.73 m(2)) and normal eGFR (eGFR>60 ml/min/1.73 m(2)). Logistic regression analysis was used for statistical analysis.

RESULTS

Whereas univariate logistic regression analysis showed that gender, diabetes duration, triglyceride, HDL cholesterol, uric acid, urinary albumin, and soluble TNF receptors (sTNF-R1, sTNF-R2) are associated with the development of stage 3 CKD, multivariate logistic regression analysis revealed that sTNF-R2 (Odds ratio 1.003, 95% confidence interval 1.000 to 1.005, P=0.030) showed significant associations with the development of stage 3 CKD.

CONCLUSIONS

Circulating TNF receptor 2 is an independent risk factor for CKD in non-obese Japanese patients with type 2 diabetes.

Low circulating adiponectin levels are associated with insulin resistance in non-obese peritoneal dialysis patients

In patients with end-stage renal disease (ESRD), circulating adipokine levels are increased due to decreased renal clearance, irrespective of obesity. However, whether adipokines play a role in the development of insulin resistance (IR) in non-obese ESRD patients is unknown. We conducted a cross-sectional study to identify factors associated with IR in 62 non-obese patients on peritoneal dialysis (PD). Non-obesity was defined as body mass index (BMI) <25 kg/m(2). IR was determined using homeostatic model assessment-IR (HOMA-IR). We also measured serum concentrations of adiponectin, leptin, resistin, high-sensitivity C-reactive protein (hsCRP), and IL-6. The average BMI of the study patients was 21.6 kg/m(2). When patients were divided into two groups according to the median value of HOMA-IR, serum adiponectin levels were significantly lower in patients with HOMA-IR > 1.85 than in those with HOMA-IR ≤1.85, whereas serum concentrations of leptin and resistin did not differ between the two groups. In addition, log-transformed HOMA-IR was negatively correlated with adiponectin (γ = -0.464, P < 0.001) and log-transformed high-density lipoprotein cholesterol (γ = -0.250, P = 0.050) and positively correlated with age (γ = 0.334, P = 0.008) and triglyceride (γ = 0.392, P = 0.002). However, resistin, log-transformed leptin and log-transformed hsCRP were not associated with HOMA-IR. In a multiple linear regression model, adiponectin was independently associated with HOMA-IR (β = -0.023, P = 0.015). In conclusion, this study suggests that low circulating adiponectin levels might be involved in IR even in non-obese patients undergoing PD.

Principal component 1 score calculated from metabolic syndrome diagnostic parameters is a possible marker for the development of metabolic syndrome in middle-aged Japanese men without treatment for metabolic diseases

PURPOSE

The risk of metabolic syndrome (MetS) is assessed based on the presence of risk factors that include dyslipidemia, hyperglycemia, hypertension and obesity. In this study, we assessed the risk of MetS using principle component (PC) analysis of MetS diagnostic parameters and examined whether the resulting eigenvalues are associated with the circulating concentrations of inflammatory cytokines [interleukin (IL)-1β and IL-6] and a marker for insulin sensitivity (adiponectin) in middle-aged Japanese men without treatment for metabolic diseases.

MATERIALS

We conducted a cross-sectional study of 308 Japanese men without treatment for metabolic diseases aged 40-69 years who participated in health checkups in Japan. We calculated the PC1 score from the following MetS diagnostic parameters: body mass index (BMI), fasting blood glucose, diastolic blood pressure, triacylglycerol and high-density lipoprotein cholesterol. We compared the relationship between PC1 scores and other clinical parameters, including IL-1β, IL-6 and adiponectin, by Spearman's rank correlation coefficient analyses and Jonckheere-Terpstra test.

RESULTS

The associations for most clinical parameters were higher with the PC1 score than with other MetS diagnostic parameters. Homeostasis model assessment-insulin resistance, an index of insulin resistance, showed stronger associations with PC1 score than with MetS diagnostic parameters. Significant associations for IL-1β, IL-6 and adiponectin were observed with the PC1 score, BMI and triacylglycerol; these associations were higher with the PC1 score than with BMI and triacylglycerol.

CONCLUSIONS

The present results show that the PC1 score is closely associated with parameters of MetS, inflammation and insulin resistance.

Population differences in proinflammatory biology: Japanese have healthier profiles than Americans

The pleiotropic cytokine, interleukin-6 (IL-6), has emerged as a key factor in the biology of aging and the physiology of inflammation. Yet much of what we know about the normal functioning of IL-6 has been generated primarily from research on European populations and Americans of European descent. Our analyses compared IL-6 levels in 382 middle-aged and older Japanese to the values found in 1209 Caucasian- and African-Americans from the Midlife in the United States survey (MIDUS). Across the life span from 30 to 80 years of age, mean IL-6 levels were strikingly lower in Japanese individuals. Significantly lower levels of C-reactive protein (CRP) and fibrinogen (FBG) provided confirmatory evidence for a population difference in proinflammatory activity. Because IL-6 release has been associated with obesity, differences in body mass index (BMI) were taken into consideration. Japanese had the lowest, and African-Americans had the highest overall BMIs, but significant group differences in IL-6 persisted even after BMI was included as a covariate in the analyses. Additional support for distinct variation in IL-6 biology was generated when systemic levels of the soluble receptor for IL-6 (sIL-6r) were evaluated. Serum sIL-6r was higher in Japanese than Americans, but was most notably low in African-Americans. Our cytokine data concur with national differences in the prevalence of age-related illnesses linked to inflammatory physiology, including cardiovascular disease. The findings also highlight the importance of broadening the diversity of people included in population studies of health and aging, especially given the relative paucity of information for some Asian countries and on individuals of Asian heritage living in the US.

Plasma interleukin-1β concentrations are closely associated with fasting blood glucose levels in healthy and preclinical middle-aged nonoverweight and overweight Japanese men

Plasma interleukin (IL)-1β and IL-6 are markers that predict the risk of inflammation in diabetes. In the current study, we examined the relationship between fasting glucose and plasma inflammatory cytokines (IL-1β and IL-6) concentrations in healthy and preclinical middle-aged Japanese men (mean ± SD, 58.7 ± 7.8 years old) divided according to body mass index (<25 kg/m(2), nonoverweight group; ≥25 kg/m(2), overweight group). We conducted a cross-sectional study of 413 healthy and preclinical men aged 40 to 69 years who participated in health checkups in Japan. We measured their clinical parameters, lifestyle factors, and plasma IL-1β and IL-6 concentrations. Participants were classified according to their fasting blood glucose levels, and we compared their plasma cytokine levels. Plasma IL-1β and IL-6 levels in nonoverweight subjects were positively and strongly associated with fasting blood glucose and hemoglobin A(1c); in contrast, these cytokines were strongly associated with homeostasis model assessment of insulin resistance and fasting glucose in overweight subjects. Significant positive associations between plasma IL-1β and glucose concentrations were observed within the groups classified according to glucose concentrations, after adjustment for age and body mass index. The results of our current study show that plasma IL-1β levels are strongly associated with fasting blood glucose concentrations in healthy and preclinical nonoverweight and overweight Japanese men.

Relationships between plasma adiponectin and body fat distribution, insulin sensitivity, and plasma lipoproteins in Alaskan Yup'ik Eskimos: the Center for Alaska Native Health Research study

Adiponectin, a protein secreted by adipose tissue, has antiatherogenic, anti-inflammatory, and insulin-sensitizing actions. We examined the relationship between plasma adiponectin and adiposity, insulin resistance, plasma lipids, glucose, leptin, and anthropometric measurements in 316 adult men and 353 adult women Yup'ik Eskimos in Southwest Alaska. Adiponectin concentration was negatively associated with body mass index, percentage of body fat, sum of skin folds, waist circumference, triglycerides, insulin resistance (homeostasis model assessment of insulin resistance [HOMA-IR]), fasting insulin, and leptin in both men and women, and also with glucose in women. Adiponectin concentration correlated positively with high-density lipoprotein cholesterol concentration, and also with low-density lipoprotein cholesterol in women. Insulin-sensitive individuals (HOMA-IR <3.52, n = 442) had higher plasma adiponectin concentrations than more insulin-resistant individuals (HOMA-IR >or=3.52, n = 224): 11.02 +/- 0.27 microg/mL vs 8.26 +/- 0.32 microg/mL, P < .001. Adiponectin concentrations did not differ between groups of participants with low and high level of risk for developing coronary heart disease. No difference in plasma adiponectin levels was found among Yup'ik Eskimos and whites matched for sex, age, and body mass index. In conclusion, circulating adiponectin concentrations were most strongly associated with sum of skin folds in Yup'ik men and with high-density lipoprotein cholesterol levels, sum of skin folds, waist circumference, and insulin and triglycerides concentrations in Yup'ik women.

Reduced GFR and albuminuria in Chinese type 2 diabetes mellitus patients are both independently associated with activation of the TNF-alpha system

AIMS/HYPOTHESIS

The involvement of chronic inflammation in albuminuria and renal function was investigated in a cross-sectional study of 320 type 2 diabetic Chinese patients from the Singapore Diabetes Cohort Study.

METHODS

Plasma levels of TNF-alpha and its two cellular receptors and of IL-6 and C-reactive protein (CRP) were measured. A composite TNF-alpha score was extracted using principal component analysis. Multiple linear regression analysis was implemented to evaluate the relationship between log( e ) (ln) albumin:creatinine ratio (ACR) and estimated GFR (eGFR) with the inflammatory variables and other clinical covariates. A Bonferroni correction was applied based on the total number of variables entered into regression analyses.

RESULTS

ln ACR was significantly associated with TNF-alpha score independently of eGFR even after a Bonferroni correction. TNF-alpha score was also significantly associated with eGFR independently of ln ACR even after correction for multiple testing. These findings were similar when the individual molecules of the TNF-alpha system were analysed separately instead of using the composite TNF-alpha score. No association was observed for IL-6 and CRP with either renal trait. Diabetes duration was a significant predictor for ln ACR but not eGFR. Conversely, age was significantly associated with eGFR but not ln ACR.

CONCLUSIONS/INTERPRETATION

Activation of the TNF-alpha system may potentially exert independent effects on ln ACR and eGFR in type 2 diabetes. Because of the study design, one may also consider the possibility that changes in these renal traits may conversely be responsible for such an inflammatory response.

Effect of insulin sensitivity on severity of heart failure

Insulin resistance is associated with various cardiac dysfunctions both molecularly and clinically, including cardiac muscle relaxation and blood flow. Although, these dysfunctions result in heart failure, relationship between insulin resistance and severity of heart failure is not well studied yet. Since severity of chronic heart failure can be determined by exercise tolerance, we attempted to assess the insulin resistance in patients with chronic heart failure and evaluated the relationship between insulin sensitivity and exercise tolerance. We examined nine chronic heart failure patients. Insulin sensitivity was determined with euglycemic hyperinsulinemic clamp technique. Exercise tolerance was assessed using cardiopulmonary exercise testing. There was no correlation between body mass index and insulin sensitivity, while between body fat ratio, significant negative correlation was investigated (r=-0.463). Insulin sensitivity was negatively correlated with exercise tolerance (with anaerobic threshold, r=0.548; with peak oxygen uptake, r=0.581). Insulin sensitivity also showed significant positive correlation with cardiac function during exercise (GIR versus peak oxygen pulse: r=0.535). Insulin sensitivity is revealed to have some effects on exercise tolerance and cardiac function in patients with chronic heart failure. Insulin resistance seems to be one of the important targets in managing the chronic heart failure.

Serum resistin level is associated with insulin sensitivity in Japanese patients with type 2 diabetes mellitus

Impaired insulin secretion and decreased insulin sensitivity are the main pathophysiologic features responsible for development of hyperglycemia in type 2 diabetes mellitus. Insulin resistance is often associated with increased adipose tissue mass. To examine which variables influence insulin sensitivity, we compared metabolic parameters, serum resistin, leptin, and adiponectin concentrations to the insulin sensitivity, obtained by frequently sampled intravenous glucose tolerance test using the minimal model analysis, in 113 Japanese patients with type 2 diabetes mellitus. Duration of diabetes, fasting plasma glucose, fasting insulin, homeostasis model assessment of insulin resistance index, and serum resistin concentration were significantly higher in the insulin-resistant subgroup compared with the insulin-sensitive subgroup and correlated with insulin sensitivity. Stepwise regression analysis also identified these parameters as independent regulators of insulin sensitivity. The present study reconfirmed that fasting insulin level or homeostasis model assessment of insulin resistance would be a surrogate measure of insulin resistance and demonstrated that insulin resistance increases progressively after the onset of overt diabetes and that the serum resistin level is associated with insulin sensitivity, suggesting that resistin plays an important role in the development of insulin resistance in Japanese patients with type 2 diabetes mellitus.

An exercise intervention without weight loss decreases circulating interleukin-6 in lean and obese men with and without type 2 diabetes mellitus

Obesity and type 2 diabetes mellitus (T2DM) have been associated with a state of chronic low-grade inflammation. We examined the effect of exercise without weight loss on circulating inflammatory biomarkers in previously sedentary lean men and obese men with and without T2DM. Middle-aged men (8 lean, 8 obese, and 8 obese with T2DM) performed 60 minutes of aerobic exercise 5 times per week for 12 weeks without a reduction in body weight. Subjects underwent a hyperinsulinemic-euglycemic clamp before and after the 12-week exercise program to assess insulin sensitivity. Circulating interleukin-6 (IL-6), plasminogen activator inhibitor-1 (PAI-1), and C-reactive protein concentrations were measured by sandwich enzyme-linked immunosorbent assay before and after the exercise intervention. Body fat was measured using magnetic resonance imaging, and waist circumference was recorded for each subject pre- and postexercise intervention. Waist circumference and plasma IL-6 concentrations were significantly lower (P < .05) after exercise training despite no change in body weight or insulin sensitivity. There were no correlations between insulin sensitivity and IL-6. Fasting plasma PAI-1 concentration was significantly lower in the lean group compared with the obese group both pre- and postexercise intervention (P < .05). There were no changes in C-reactive protein or PAI-1 concentrations after exercise training. A 12-week exercise intervention led to reductions in waist circumference and fasting IL-6 concentrations in previously sedentary lean and obese men with or without T2DM, demonstrating significant changes in clinically relevant diabetes-related parameters despite no change in body weight.

Adiponectin and leptin: potential tools in the differential diagnosis of pediatric diabetes?

The incidence of type 1 and type 2 diabetes mellitus in the pediatric population has increased over the past decade. The practitioner is often faced with the challenge of differentiating between type 1 and type 2 diabetes at the time of initial diagnosis because of the overlap of clinical and laboratory characteristics between these two entities. Adipokines are proteins secreted by the adipose tissue. Leptin and adiponectin are two adipokines that have been extensively studied in vitro, in animal studies, and in human subjects with type 1 and type 2 diabetes. Leptin and adiponectin play a significant role in the regulation of lipid and carbohydrate metabolism. Adiponectin increases insulin sensitivity in both the liver and skeletal muscle. Leptin decreases appetite, increases energy expenditure, suppresses insulin synthesis and secretion and increases insulin sensitivity. Changes in the secretion or sensitivity to leptin and adiponectin may contribute to the development of type 1 and type 2 diabetes. Adiponectin is higher in adult and pediatric patients with type 1 diabetes compared to those with type 2 diabetes. Data regarding leptin levels are contradictory. Most studies report decreased serum leptin at the time of diagnosis in type 1 diabetes compared to type 2 diabetes subjects and non-diabetic controls. This paper will review basic research and clinical evidence supporting the role of adiponectin and leptin in the development of type 1 and type 2 diabetes and discuss their potential use as tools in the differential diagnosis of pediatric diabetes.