Relationship of serum adiponectin and resistin to glucose intolerance and fat topography in South-Asians

Ischaemic stroke in South Asians: The BRAINS study

BACKGROUND AND PURPOSE

Studies on stroke in South Asian populations are sparse. The aim of this study was to compare differences in age of onset of ischaemic stroke in South Asian patients living in the United Kingdom and South Asian patients living in India versus White British stroke patients.

METHODS

We studied the UK and Indian arms of the ongoing BRAINS study, an international prospective hospital-based study of South Asian stroke patients. The BRAINS study includes 4038 South Asian and White British patients with first-ever ischaemic stroke, recruited from sites in the United Kingdom and India.

RESULTS

Of the included patients, 1126 were South Asians living in India (ISA), while 1176 were British South Asian (BSA) and 1736 were White British (WB) UK residents. Patients in the ISA and BSA groups experienced stroke 19.5 years and 7.2 years earlier than their WB counterparts, respectively (mean [interquartile range] age: BSA 64.3 [22] years vs. ISA 52.0 [18] years vs. WB 71.5 [19] years; p < 0.001). Patients in the BSA group had higher rates of hypertension, diabetes mellitus and hypercholesterolaemia than those in the ISA and WB groups. After adjustment for traditional stroke risk factors, an earlier age of stroke onset of 18.9 years (p < 0.001) and 8.9 years (p < 0.001) was still observed in the ISA and BSA groups, respectively. In multivariable stepwise linear regression analysis, ethnicity accounted for 24.7% of the variance in early age onset.

CONCLUSION

Patients in the BSA and ISA groups experienced ischaemic stroke approximately 9 and 19 years earlier, respectively, than their WB counterparts. Ethnicity is an independent predictor of early age of stroke onset. Our study has considerable implications for public health policymakers in countries with sizable South Asian populations.

Changes in adipokine concentrations in antidepressant-resistant bipolar depression after ketamine infusion and electroconvulsive therapy

OBJECTIVES

This study attempts to assess the concentration of two opposite-acting adipokines (anti-inflammatory adiponectin and pro-inflammatory resistin) in antidepressant-resistant patients undergoing ketamine infusion (KI) and electroconvulsive therapy (ECT).

METHODS

The study group comprised 52 patients hospitalised due to episodes of depression in the course of bipolar disorders. The Hamilton depression scale was used to assess the intensity of the depression symptoms before starting therapy and one day after its completion. The serum concentration of adipokines was determined before and after the therapeutic intervention using an ELISA method.

RESULTS

Baseline adipokine levels differed between patients receiving KI and ECT therapy. Regardless of the procedure used, these levels changed after treatment, with the nature of these changes being different. In the case of KI, the adiponectin levels increased, and resistin levels decreased. In contrast, after ECT, the concentrations of both adipokines decreased. Changes in adipokine concentrations correlated with improvement in mental status, as assessed by the Hamilton Rating Scale, type of bipolar disorder, and gender.

CONCLUSIONS

Adipokines remain interesting candidate biomarkers in assessing the state and course of the disease depending on the therapeutic procedure applied. However, the relatively small study group and limited original research available for discussion justify further investigation.

Assessment of Adiponectin and Resistin Indexes Compared to FBG and Useful as Diagnostic Biomarkers in Insulin Resistance and Type 2 Diabetes

Abstract: Background and aim: The world prevalence of diabetes among adults will be 6.4%, affecting 285 million adults, in year 2010, and will increase to 7.7% and 439 million adults by year 2030. Insulin resistance is a prerequisite root factor for development of type 2 diabetes (T2DM). Adiponectin and resistin are adipokines which modulate insulin action, energy, glucose and lipid homeostasis. Meta-analyses showed that hypoadiponectinemia and hyperresistinemia are strongly associated with increased risk of insulin resistance, type 2 diabetes (T2DM), Methods: In this case control study, A total 204 Sudanese males and females were recruited to participate in this study (102 diabetic and 102 non-diabetic) and venous blood samples were collected. Serum levels of blood glucose were measured using the particle-enhanced immunoturbidimetric assay method Cobas C-311®.While Adiponectin and Resistine estimated by ELISA Kits. Results: In this results shows significant difference between the means fasting blood glucose (FBG), adiponectin, resistine of diabetic patient and non-diabetic patient. FBG (mean + SD) (164.5 ± 16.7) versus (95.7 ± 13.6), P = 0.041, adiponectin (mean + SD) (5.9 ± 1.6) versus (10.1 ± 1.3), P = 0.037, resistine (mean + SD) (18.2 ± 2.7) versus (12.2 ± 1.1), P = 0.023.  In this study, observed from this results strong negative Correlation between the levels of serum Adiponectin and Fasting Blood Glucose, Adiponectin and Resistine. (P.value = 0.013, r = -7.9). (P.value = 0.019, r = -6.6). While showing in the other side moderate positive Correlation between the levels of serum Resistine and Fasting Blood Glucose. (P.value = 0.015, r = 6.0). Conclusion: Iccrease of Resistine and Fasting Blood Glucose and reduced of Adiponectin in diabetic patient compare to non-diabetic patient can be useful as diagnostic biomarkers. Keywords: Adiponectin and Resistin, insulin resistance, type 2 diabetes

Gut-Derived Endotoxin and Telomere Length Attrition in Adults with and without Type 2 Diabetes

Premature aging, as denoted by a reduced telomere length (TL), has been observed in several chronic inflammatory diseases, such as obesity and type 2 diabetes mellitus (T2DM). However, no study to date has addressed the potential inflammatory influence of the gut-derived Gram-negative bacterial fragments lipopolysaccharide, also referred to as endotoxin, and its influence on TL in low-grade inflammatory states such as type 2 diabetes mellitus (T2DM). The current study therefore investigated the influence of endotoxin and inflammatory factors on telomere length (TL) in adults with (T2DM: n = 387) and without (non-diabetic (ND) controls: n = 417) obesity and T2DM. Anthropometric characteristics were taken, and fasted blood samples were used to measure biomarkers, TL, and endotoxin. The findings from this study highlighted across all participants that circulating endotoxin (r = -0.17, p = 0.01) was inversely associated with TL, noting that endotoxin and triglycerides predicted 18% of the variance perceived in TL (p < 0.001). Further stratification of the participants according to T2DM status and sex highlighted that endotoxin significantly predicted 19% of the variance denoted in TL among male T2DM participants (p = 0.007), where TL was notably influenced. The influence on TL was not observed to be impacted by anti-T2DM medications, statins, or anti-hypertensive therapies. Taken together, these results show that TL attrition was inversely associated with circulating endotoxin levels independent of the presence of T2DM and other cardiometabolic factors, suggesting that low-grade chronic inflammation may trigger premature biological aging. The findings further highlight the clinical relevance of mitigating the levels of circulating endotoxin (e.g., manipulation of gut microbiome) not only for the prevention of chronic diseases but also to promote healthy aging.

Obesity, adipocyte hypertrophy, fasting glucose, and resistin are potential contributors to nonalcoholic fatty liver disease in South Asian women

Purpose: Nonalcoholic fatty liver disease (NAFLD) is often referred to as the hepatic manifestation of the metabolic syndrome. The relationship between body weight, NAFLD, and insulin resistance is not well characterized in humans. Additionally, it is unclear why South Asians develop these complications at lower levels of obesity compared to their Western counterparts. Patients and methods: To address this question, we performed a cross-sectional study using a convenience sample of Sri Lankan adult females (n=34) and collected anthropometric data, adipose tissue specimens (for histology), and fasted serum samples (for metabolic and inflammatory markers). Hepatic steatosis was assessed by ultrasound scanning and used to classify participants as NAFL 0, NAFL 1, and NAFL 2. Results: Waist circumference significantly increased with increasing NAFL grade. Participants with NAFL had significantly higher body mass index, hip circumference, and fasting plasma glucose, as well as a higher mean adipocyte area in both abdominal subcutaneous and visceral areas, indicating a higher degree of adipocyte hypertrophy associated with fatty liver. There were, however, no differences in measures of dyslipidemia. Of the multiple adipokines measured, resistin was the only proinflammatory adipokine significantly elevated in NAFL 2. Conclusion: These findings indicate that measures of adiposity, fasting serum glucose, and resistin may be important indicators of NAFLD in South Asian women.

South Asian Cardiovascular Disease & Cancer Risk: Genetics & Pathophysiology

South Asians (SAs) are at heightened risk for cardiovascular disease as compared to other ethnic groups, facing premature and more severe coronary artery disease, and decreased insulin sensitivity. This disease burden can only be partially explained by conventional risk factors, suggesting the need for a specific cardiovascular risk profile for SAs. Current research, as explored through a comprehensive literature review, suggests the existence of population specific genetic risk factors such as lipoprotein(a), as well as population specific gene modulating factors. This review catalogues the available research on cardiovascular disease and genetics, anthropometry, and pathophysiology, and cancer genetics among SAs, with a geographical focus on the U.S. A tailored risk profile will hinge upon population customized classification and treatment guidelines, informed by continued research.

Associations between serum adipocytokines and glycemic tolerance biomarkers in a rural Chinese population

Although experimental studies have shown that adiponectin and leptin modulate glucose tolerance and insulin resistance, it remains unclear whether these adipocytokines exert similar effects in general human populations. We evaluated the associations of serum adiponectin and leptin with β-cell function and insulin resistance in a population with low obesity prevalence. A cross-sectional study of 783 rural residents, aged 25-74 years, recruited in Ningxia, China was conducted during 2008-2012. β-cell function and insulin resistance were estimated using the Homeostasis Model Assessment. Serum adiponectin and leptin were measured with ELISA. Serum adiponectin concentrations (mean ± SD) were highest in subjects with normal glucose tolerance (36.65 ± 61.13 μg/ml), intermediate in those with impaired fasting glucose (25.92 ± 34.48 μg/ml), and lowest in those with diabetes (15.08 ± 12.14 μg/ml) (p = 0.001). A similar pattern of differences was found for β-cell function, whereas opposite results were observed for insulin resistance and blood glucose. After adjustment for confounders including metabolic syndrome components, serum adiponectin (μg/ml) was inversely associated with β-cell function (%β) [β (95% CI): -7.57 (-12.33, -2.81)] and insulin resistance (100/%S) [β (95% CI): -0.21 (-0.33, -0.09)]. A significant inverse association also existed between serum leptin and β-cell function, but serum leptin was not significantly associated with insulin resistance. The present study suggests that adiponectin and leptin play a role in the development of insulin resistance and diabetes independent of metabolic syndrome.

Impact of baseline body mass index status on glucose lowering and weight change during sitagliptin treatment for type 2 diabetics

AIMS

This study was designed to evaluate the efficacy of sitagliptin in Taiwanese diabetic subjects with different baseline BMI status.

METHODS

This was a single-center, hospital-based, retrospective chart review in subjects (n=1874) with type 2 diabetes who received sitagliptin. Subjects were classified into subgroups depending upon their baseline BMI by Taiwan national weight classification: normal (BMI<24kg/m(2)) (n=504), overweight (BMI: 24-27kg/m(2)) (n=615), and obese (BMI⩾27kg/m(2)) (n=755). Changes in HbA1c and weight were evaluated over a 12month treatment period.

RESULTS

For all three groups, the HbA1c levels declined over the first three months by about 8%, and subsequently plateaued for the next nine months. Obese subjects were slower in reducing HbA1c compared with normal and overweight subjects (P<0.05), but at nine months the reduction was similar across groups. Mean body weight increased over the first nine months of sitagliptin therapy in subjects with normal BMI (57.12-58.30kg), but there was no change in mean body weight in the overweight group. After three months the obese groups had significantly greater loss in body weight compared with the normal group.

CONCLUSIONS

Baseline BMI status may influence the reduction of HbA1c levels within the first six months of sitagliptin therapy and affect weight change after three months. Being obese was associated with an initial lag in HbA1c reduction and greater weight loss compared with normal and overweight subjects.

Less favorable body composition and adipokines in South Asians compared with other US ethnic groups: results from the MASALA and MESA studies

Background

Small studies have shown that South Asians (SAs) have more total body, subcutaneous, visceral and hepatic fat and abnormal adipokine levels compared to Whites. However, comprehensive studies of body composition and adipokines in SAs compared to other ethnic groups are lacking.

Methods

Using harmonized data, we performed a cross-sectional analysis of two community-based cohorts: Mediators of Atherosclerosis of South Asians Living in America (MASALA, n=906) and Multi-Ethnic Study of Atherosclerosis (MESA which included 2,622 Whites; 803 Chinese Americans; 1,893 African Americans; and 1,496 Latinos). General linear models were developed to assess ethnic differences in ectopic fat (visceral, intermuscular, and pericardial fat; and hepatic attenuation), lean muscle mass, and adipokines (adiponectin and resistin). Models were adjusted for age, sex, site, alcohol use, smoking, exercise, education, household income and BMI. Ectopic fat models were additionally adjusted for hypertension, diabetes, HDL, and triglycerides. Adipokine models were adjusted for subcutaneous, visceral, intermuscular, and pericardial fat; and hepatic attenuation.

Results

Compared to all ethnic groups in MESA (Whites, Chinese Americans, African Americans, and Latinos), SAs had greater intermuscular fat (pairwise comparisons to each MESA group, p < 0.01), lower hepatic attenuation (p < 0.001), and less lean mass (p < 0.001). SAs had greater visceral fat compared to Chinese Americans, African Americans and Latinos (p < 0.05) and greater pericardial fat compared to African Americans (p < 0.001). SAs had lower adiponectin levels compared to other ethnic groups (p < 0.01; except Chinese Americans) and higher resistin levels than all groups (p < 0.001), even after adjusting for differences in body composition.

Conclusion

There are significant ethnic differences in ectopic fat, lean mass, and adipokines. A less favorable body composition and adipokine profile in South Asians may partially explain the increased predisposition to cardiometabolic disease. The mechanisms that underlie these differences warrant further investigation.

Cardiovascular Disease in South Asian Migrants

Cardiovascular disease (CVD) represents a significant cause of global mortality and morbidity. South Asians (SAs) have a particularly high burden of coronary artery disease (CAD). This review describes current literature regarding the prevalence, incidence, etiology, and prognosis of CVD in SA migrants to high-income nations. We conducted a narrative review of CVD in the SA diaspora through a search of MEDLINE and PubMed. We included observational studies, randomized clinical trials, nonsystematic reviews, systematic reviews, and meta-analyses written in English. Of 15,231 articles identified, 827 articles were screened and 124 formed the basis for review. SA migrants have a 1.5-2 times greater prevalence of CAD than age- and sex-adjusted Europids. Increased abdominal obesity and body fat and increased burden of type 2 diabetes mellitus and dyslipidemia appear to be primary drivers of the excess CAD burden in SAs. Sedentary lifestyle and changes in diet after immigration are important contributors to weight gain and adiposity. Early life factors, physical activity patterns and, in some cases, reduced adherence to medical therapy may contribute to increased CVD risks in SAs. Novel biomarkers like leptin and adipokines may show distinct patterns in SAs and provide insights into cardiometabolic risk determinants. In conclusion, SAs have distinct CVD risk predispositions, with a complex relationship to cultural, innate, and acquired factors. Although CVD risk factor management and treatment among SAs is improving, opportunities exist for further advances.

Diabetes and associated complications in the South Asian population

The rising prevalence of diabetes in South Asians has significant health and economic implications. South Asians are predisposed to the development of diabetes due to biologic causes which are exacerbated by lifestyle and environmental factors. Furthermore, they experience significant morbidity and mortality from complications of diabetes, most notably coronary artery disease, cerebrovascular disease, and chronic kidney disease. Therefore, understanding the pathophysiology and genetics of diabetes risk factors and its associated complications in South Asians is paramount to curbing the diabetes epidemic. With this understanding, the appropriate screening, preventative and therapeutic strategies can be implemented and further developed. In this review, we discuss in detail the biologic and lifestyle factors that predispose South Asians to diabetes and review the epidemiology and pathophysiology of microvascular and macrovascular complications of diabetes in South Asians. We also review the ongoing and completed diabetes prevention and management studies in South Asians.

Adiponectin-resistin index and its strong association with acute coronary syndrome in South Indian men

BACKGROUND

India has the highest burden of acute coronary syndromes worldwide. Apart from certain lipid alterations that have been established to be definite risk factors, low level of adiponectin, high levels of resistin, and IL-6 have been shown to be risk factors for cardiovascular events. Insulin resistance is also a significant predictor of poor outcome in patients admitted with ACS.

METHODS

69 male patients with ACS and 70 age-matched healthy males were recruited in the study. Insulin, total adiponectin, resistin, and IL-6 levels were assayed in all study subjects. Indices of insulin resistance and novel adipokine indices were calculated using standard formulae. Multiple logistic regression analysis was done to find out the best predictor of ACS.

RESULTS

Resistin, IL-6, insulin resistance indices, AR index, and IRAR index were found to be significantly higher, while insulin sensitivity indices and total adiponectin were found to be lower in cases, as compared with controls (p < 0.001). Insulin resistance was found to be higher in the admission sample, when compared to the fasting sample in patients with ACS (p = 0.01). On multivariate logistic regression analysis, HOMA-IR and AR index were found to be significantly associated with ACS. AR index was the best independent predictor of ACS, with the highest odds ratio (AR index: adjusted OR 17.528, p < 0.0001 versus HOMA-IR: adjusted OR 1.146, p = 0.001).

CONCLUSIONS

The present results implicate that adipokines are significantly associated with pathogenesis of ACS, warranting adequate and early appropriate treatment to reverse this metabolic dysregulation. In our study, AR index was the best predictor of ACS. Hence, the novel AR index might be useful in routine clinical practice for screening persons with increased risk of future development of ACS.

Association of Resistin with Insulin Resistance and Factors of Metabolic Syndrome in North Indians

Metabolic syndrome (MetS) is a cluster of interrelated common clinical disorders. The role of resistin in insulin sensitivity and MetS is controversial till date. So, the aim of the present study was to investigate the relationship of plasma resistin levels with markers of the MetS in Indian subjects. In a case control study, total 528 subjects were selected for the study. 265 (194 male and 71 female) were cases (with MetS) and 263 (164 male and 99 female) were controls (without MetS). Required anthropometric measurements and calculations were carried out accordingly. All the Biochemical estimations were carried out according to standard protocol. Resistin level was measured by the standard protocol (By ELISA i.e. enzyme linked immunosorbent assay) as illustrated in the kit. Insulin level was also measured by the standard protocol as illustrated in the kit and insulin resistance was calculated by the standard procedures. Plasma resistin levels were significantly higher in cases compared with controls (male = 13.05 ± 4.31 vs. 7.04 ± 2.09 ng/ml; p ≤ 0.001 and female = 13.53 ± 4.14 vs. 7.42 ± 2.30 ng/ml; p ≤ 0.001). Plasma resistin levels were well correlated with waist circumference, glucose, triglycerides, waist/hip ratio, systolic and diastolic blood pressure, high density lipoprotein, total cholesterol, serum low density lipoprotein, serum very low density lipoprotein, insulin and insulin resistance. Plasma resistin levels were elevated in presence of the MetS and were associated with increased metabolic risk factors.

Polymorphisms in RETN gene and susceptibility to colon cancer in Saudi patients

BACKGROUND AND OBJECTIVES

Resistin is an adipocytokine, which has been studied for its role in insulin resistance and recently in inflammation. Several single-nucleotide polymorphisms (SNPs) have been identified in the human resistin gene (RETN). This study aims to investigate the association of RETN rs1862513 (C-420G) and rs3745367 (G+299A) SNPs with the colon cancer risk in Saudi patients.

DESIGN AND SETTING

This is a case-control study conducted among Saudi adult colon cancer patients recruited from King Abdulaziz Hospital and Oncology Center in Jeddah, Saudi Arabia.

SUBJECTS AND METHODS

In this study, 120 Saudi volunteers (60 colon cancer patients and 60 disease-free controls) were studied. The SNPs were determined by polymerase chain reaction (PCR) and genotyping using PCR- restriction fragment length polymorphism analysis.

RESULTS

In comparing the result obtained for the patient group with that of the controls, colon cancer group displayed different genotype distribution of the RETN C-420G and G+299A SNPs. The study indicated that the SNP-420 heterozygous (CG) genotype (odds ratio [OR]=2.48, 95% CI 1.07-5.74, P=.03) and the SNP +299 heterozygous (GA) genotype (OR=6.5, 95% CI 1.77-24.18, P=.002) significantly increased the risk of colon cancer. A further analysis of the genotype combination of SNPs RETN C-420G and G+299A showed a larger increase in the colon cancer risk.

CONCLUSION

These preliminary results suggested a potential role for RETN C-420G and G+299A polymorphisms in the genetic predisposition to colon cancer disease.

Immunomodulatory Role of an Ayurvedic Formulation on Imbalanced Immunometabolics during Inflammatory Responses of Obesity and Prediabetic Disease

Kal-1 is a polyherbal decoction of seven different natural ingredients, traditionally used in controlling sugar levels, inflammatory conditions particularly regulating metabolic and immunoinflammatory balance which are the major factors involved in obesity and related diseases. In the present study, we aimed to investigate the effect of Kal-1 (an abbreviation derived from the procuring source) on diet-induced obesity and type II diabetes using C57BL/6J mice as a model. The present study was performed with two experimental groups involving obese and prediabetic mice as study animals. In one, the mice were fed on high-fat with increased sucrose diet, and different amounts (5, 20, and 75 μL) of Kal-1 were administered with monitoring of disease progression over a period of 21 weeks whereas in the second group the mice were first put on the same diet for 21 weeks and then treated with the same amounts of Kal-1. A significant reduction in body weight, fat pads, fasting blood glucose levels, insulin levels, biochemical parameters, immunological parameters, and an array of pro- and anticytokines was observed in obese and diabetic mice plus Kal-1 than control (lean) mice fed on normal diet. In conclusion, Kal-1 has immunomodulatory potential for diet-induced obesity and associated metabolic disorders.

Pathogenesis of type 2 diabetes in South Asians

The risk of developing type 2 diabetes mellitus (T2DM) is exceptionally high among both native and migrant South Asians. T2DM occurs more often and at a younger age and lower BMI, and the risk of coronary artery and cerebrovascular disease, and renal complications is higher for South Asians compared with people of White Caucasian descent. The high prevalence of T2DM and its related complications in South Asians, which comprise one-fifth of the total world's population, poses a major health and socioeconomic burden. The underlying cause of this excess risk, however, is still not completely understood. Therefore, gaining insight into the pathogenesis of T2DM in South Asians is of great importance. The predominant mechanism, in this ethnicity seems to be insulin resistance (IR) rather than an impaired β-cell function. In this systematic review, we describe several possible mechanisms that may underlie or contribute to the increased IR observed in South Asians.

Metabolic disruption in male mice due to fetal exposure to low but not high doses of bisphenol A (BPA): evidence for effects on body weight, food intake, adipocytes, leptin, adiponectin, insulin and glucose regulation

Exposure to bisphenol A (BPA) is implicated in many aspects of metabolic disease in humans and experimental animals. We fed pregnant CD-1 mice BPA at doses ranging from 5 to 50,000μg/kg/day, spanning 10-fold below the reference dose to 10-fold above the currently predicted no adverse effect level (NOAEL). At BPA doses below the NOAEL that resulted in average unconjugated BPA between 2 and 200pg/ml in fetal serum (AUC0-24h), we observed significant effects in adult male offspring: an age-related change in food intake, an increase in body weight and liver weight, abdominal adipocyte mass, number and volume, and in serum leptin and insulin, but a decrease in serum adiponectin and in glucose tolerance. For most of these outcomes non-monotonic dose-response relationships were observed; the highest BPA dose did not produce a significant effect for any outcome. A 0.1-μg/kg/day dose of DES resulted in some but not all low-dose BPA outcomes.

Resistin production from adipose tissue is decreased in db/db obese mice, and is reversed by rosiglitazone

OBJECTIVE

This study was designed to (1) investigate the expression profiles of resistin in db/db mice and its dynamic association with metabolic parameters; and (2) evaluate the effects of Rosiglitazone on production of resistin.

METHODS

Db/db mice and their lean litter mates were used for this study. Epididymal fat tissue was excised from mice of different age (from 5 to 12 weeks) for ex vivo incubation. Resistin,along with adiponectin,in serum and conditioned culture medium of epididymal fat pads were measured with immunoassays. The gene expression of resistin was determined by real-time PCR. Rosiglitazone or the vehicle (PBS) was administered into db/db mice by daily intra-gastric gavage. Differentiated 3T3-L1 adipocytes were used for in vitro evaluation.

RESULTS

The secretion of resistin from the fat pads in db/db mice was significantly lower than that in lean mice (P<0.01). The mRNA expression of the resistin gene in fat tissue of db/db mice at the age of 5 weeks was decreased by 60.5% compared to lean controls (p<0.05). Serum levels of resistin were comparable between the obese and lean groups, perhaps due to the increased total fat mass in db/db mice. Correlation analysis showed that serum resistin levels were positively correlated to resistin secretion from fat pads(r = 0.844,P = 0.000), while negatively associated with the body weight (r = -0.515, P = 0.000) and fasting glucose level (r = -0.357, P = 0.002). Notably, treatment with rosiglitazone increased the serum resistin levels by 66.4%(P<0.05)in db/db mice. In 3T3-L1 adipocytes, Rosiglitazone (10 uM) markedly enhanced the secretion of resistin by 120% (P<0.01) and its gene expression by 78.1% (P<0.05).

CONCLUSION

Both resistin gene expression and its secretion from the epididymal adipose tissue were decreased in db/db obese mice, while the insulin-sensitizing drug rosiglitazone increased resistin production. Our results do not support the role of resistin as an etiological link between obesity and diabetes.

Biochemistry of adipose tissue: an endocrine organ

Adipose tissue is no longer considered to be an inert tissue that stores fat. This tissue is capable of expanding to accommodate increased lipids through hypertrophy of existing adipocytes and by initiating differentiation of pre-adipocytes. Adipose tissue metabolism exerts an impact on whole-body metabolism. As an endocrine organ, adipose tissue is responsible for the synthesis and secretion of several hormones. These are active in a range of processes, such as control of nutritional intake (leptin, angiotensin), control of sensitivity to insulin and inflammatory process mediators (tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), resistin, visfatin, adiponectin, among others) and pathways (plasminogen activator inhibitor 1 (PAI-1) and acylation stimulating protein (ASP) for example). This paper reviews some of the biochemical and metabolic aspects of adipose tissue and its relationship to inflammatory disease and insulin resistance.

Type 2 diabetes in South Asians: similarities and differences with white Caucasian and other populations

Type 2 diabetes mellitus (T2DM) is one of the leading causes of morbidity and mortality. While all ethnic groups are affected, the prevalence of T2DM in South Asians, both in their home countries and abroad, is extremely high and is continuing to rise rapidly. Innate biological susceptibilities coupled with rapid changes in physical activity, diet, and other lifestyle behaviors are contributing factors propelling the increased burden of disease in this population. The large scope of this problem calls for investigations into the cause of increased susceptibility and preventative efforts at both the individual and population level that are aggressive, culturally sensitive, and start early. In this review, we outline the biological and environmental factors that place South Asians at elevated risk for T2DM, compared with Caucasian and other ethnic groups.

Adipocytokine associations with insulin resistance in british South asians

Aims. Adipocytokines are implicated in the pathogenesis of type 2 diabetes and may represent identifiable precursors of metabolic disease within high-risk groups. We investigated adiponectin, leptin, and TNF- α and assessed the contribution of these molecules to insulin resistance in south Asians. Hypothesis. South Asians have adverse adipocytokine profiles which associate with an HOMA-derived insulin resistance phenotype. Methods. We measured adipocytokine concentrations in south Asians with newly diagnosed impaired glucose tolerance or Type 2 Diabetes Mellitus in a case-control study. 158 (48.5% males) volunteers aged 25-75 years with risk factors for diabetes but no known vascular or metabolic disease provided serum samples for ELISA and bioplex assays. Results. Total adiponectin concentration progressively decreased across the glucose spectrum in both sexes. A reciprocal trend in leptin concentration was observed only in south Asian men. Adiponectin but not leptin independently associated with HOMA-derived insulin resistance after logistic multivariate regression. Conclusion. Diasporic south Asian populations have an adverse adipocytokine profile which deteriorates further with glucose dysregulation. Insulin resistance is inversely associated with adiponectin independent of BMI and waist circumference in south Asians, implying that adipocytokine interplay contributes to the pathogenesis of metabolic disease in this group.

Serum concentrations of resistin and adiponectin and their relationship to insulin resistance in subjects with impaired glucose tolerance

OBJECTIVES

This study measured the serum concentrations of resistin and adiponectin in Chinese subjects with impaired glucose tolerance (IGT) and investigated their association with insulin resistance, metabolic parameters and circulating inflammatory markers.

METHODS

A total of 124 subjects participated in the study (44 with IGT and 80 with normal glucose tolerance [NGT]). Fasting serum concentrations of lipids, glucose, insulin and adipocytokines (resistin, adiponectin, leptin, tumour necrosis factor-α [TNF-α], interleukin-6 and C-reactive protein) were measured.

RESULTS

Serum resistin concentrations were similar in the IGT and NGT groups but were significantly higher in overweight/ obese IGT subjects than in those of normal weight. Serum adiponectin concentrations were significantly lower in the IGT group than in the NGT group. In the IGT group, resistin was positively correlated with age, body mass index and TNF-α, and adiponectin was correlated positively with high-density lipoprotein cholesterol and negatively with TNF-α and waist/hip ratio.

CONCLUSIONS

Circulating resistin is unlikely to be a major mediator of glucose tolerance in humans but it may have an inflammatory role in IGT. The data support the theory that circulating adiponectin has an anti-inflammatory and anti-insulin resistance function.

Accelerated aging as evidenced by increased telomere shortening and mitochondrial DNA depletion in patients with type 2 diabetes

Although shortened telomeres were shown associated with several risk factors of diabetes, there is lack of data on their relationship with mitochondrial dysfunction. Therefore, we compared the relationship between telomere length and mitochondrial DNA (mtDNA) content in patients with type 2 diabetes mellitus (T2DM; n = 145) and in subjects with normal glucose tolerance (NGT; n = 145). Subjects were randomly recruited from the Chennai Urban Rural Epidemiology Study. mtDNA content and telomere length were assessed by Real-Time PCR. Malonodialdehyde, a marker of lipid peroxidation was measured by thiobarbituric acid reactive substances (TBARS) using fluorescence methodology. Adiponectin levels were measured by radioimmunoassay. Oxidative stress as determined by lipid peroxidation (TBARS) was significantly (p < 0.001) higher in patients with T2DM compared to NGT subjects. In contrast, the mean telomere length, adiponectin and mtDNA content were significantly (p < 0.001) lower in patients with T2DM compared to NGT subjects. Telomere length was positively correlated with adiponectin, HDL, mtDNA content and good glycemic/lipid control and negatively correlated with adiposity and insulin resistance. On regression analysis, shortened telomeres showed significant association with T2DM even after adjusting for waist circumference, insulin resistance, triglyceride, HDL, adiponectin, mtDNA & TBARS. mtDNA depletion showed significant association with T2DM after adjusting for waist circumference and adiponectin but lost its significance when further adjusted for telomere length, TBARS and insulin resistance. Our study emphasizes the clustering of accelerated aging features viz., shortened telomeres, decreased mtDNA content, hypoadiponectinemia, low HDL, and increased oxidative stress in Asian Indian type 2 diabetes patients.

Association of circulating resistin with metabolic risk factors in Indian females having metabolic syndrome

Role of resistin in insulin sensitivity and metabolic syndrome (MetS) is controversial till date. Increased serum resistin levels are associated with MetS and insulin resistance. The aim of this study was to investigate the relationship between serum resistin levels with markers of the MetS in females. In a cross-sectional study, a total of 170 healthy female subjects were selected for the study. Out of which 71 (age 31.59 ± 4.88 years) were with MetS and 99 (age 31.75 ± 6.34 years) were without MetS. Different parameters of MetS and serum resistin level were measured according to the standard protocols as given in NCEP ATP III 2001 guideline. Serum resistin levels were significantly higher in subjects with MetS when compared with subjects without MetS [13.54 ± 4.14 ng/ml (n = 71) vs. 7.42 ± 2.31 ng/ml (n = 99); P ≤ 0.001]. Resistin levels were positively associated with waist circumference, systolic and diastolic blood pressure, plasma glucose, waist/hip ratio, serum triglycerides, serum cholesterol, serum VLDL, plasma insulin, and insulin resistance, while it was negatively associated with high-density lipoprotein. This study demonstrates a positive correlation between resistin and factors of MetS except high-density lipoprotein which was found to be negatively correlated in Indian female subjects.

Adipokines and body fat composition in South Asians: results of the Metabolic Syndrome and Atherosclerosis in South Asians Living in America (MASALA) study

Objective

To investigate whether leptin and adiponectin are associated with body fat composition in a South Asian population independent of metabolic variables.

Design

Cross-sectional study

Subjects

150 South Asian men and women, between the ages of 45–79 years, in the San Francisco Bay Area without pre-existing clinical cardiovascular disease.

Measurements

Blood samples were obtained to measure glucose metabolism variables, lipid profiles and adipokines. Total body fat was determined using dual-energy x-ray absorptiometry. Abdominal computed tomography was used to measure subcutaneous, visceral, and hepatic fat.

Results

Average body mass index (BMI) was overweight at 26.1±4.6 kg/m² and did not differ by sex. However, women had significantly more total body fat (p<0.001) and subcutaneous fat (p<0.001) than men, while men had significantly more visceral fat (p<0.001) and hepatic fat (p=0.04) than women. Women had significantly higher levels of adiponectin (p<0.01) and leptin (p<0.01). In sex-stratified analyses, leptin was strongly associated with all body composition measures in women (p<0.05) as well as in men (p<0.05 except for hepatic fat) while there was an insignificant trend towards an inverse association between adiponectin and body composition in both women and men which was significant in combined bivariate analyses. In multivariate analyses, leptin was strongly associated with all measures of adiposity, including BMI (p<0.001), total body fat (p<0.001), visceral fat (p<0.001), and hepatic fat (p=0.01). However, adiponectin’s inverse association with adiposity was significantly attenuated by high-density lipoprotein (HDL), triglycerides, and insulin resistance. The association between adipokines and diabetes was markedly attenuated after adjusting for body composition.

Conclusion

Despite only modestly elevated BMI, South Asians have elevated levels of total and regional adiposity. Leptin is strongly associated with adiposity while adiponectin’s association with adiposity is attenuated by metabolic variables in South Asians. Adipokines in association with adiposity play an important role in the development of diabetes.

Type 2 diabetes and cardiovascular disease in South Asians

Type 2 diabetes (T2DM) is growing at a pandemic scale and is associated with a rapid increase in its complications such as cardiovascular diseases (CVD). This problem is even worse in South Asian population with South Asian people having a much higher prevalence of T2DM and CVD, occurring at an earlier age and being associated with premature and high mortality. This review looks in detail at the current knowledge on epidemiology and characteristic pathophysiology of T2DM and CVD (coronary heart disease, heart failure, stroke and peripheral vascular disease) in South Asian migrant population. Specific attention is also drawn to the role of novel risk factors and cultural and socioeconomic factors on occurrence and outcomes of these chronic diseases in this population. Finally the review makes recommendations on various measures including need for further research to tackle this serious health challenge facing the South Asian community.

Novel adiponectin-resistin (AR) and insulin resistance (IRAR) indexes are useful integrated diagnostic biomarkers for insulin resistance, type 2 diabetes and metabolic syndrome: a case control study

Background

Adiponectin and resistin are adipokines which modulate insulin action, energy, glucose and lipid homeostasis. Meta-analyses showed that hypoadiponectinemia and hyperresistinemia are strongly associated with increased risk of insulin resistance, type 2 diabetes (T2DM), metabolic syndrome (MS) and cardiovascular disease. The aim of this study was to propose a novel adiponectin-resistin (AR) index by taking into account both adiponectin and resistin levels to povide a better indicator of the metabolic homeostasis and metabolic disorders. In addition, a novel insulin resistance (IR_AR) index was proposed by integration of the AR index into an existing insulin resistance index to provide an improved diagnostic biomarker of insulin sensitivity.

Methods

In this case control study, anthropometric clinical and metabolic parameters including fasting serum total adiponectin and resistin levels were determined in 809 Malaysian men (208 controls, 174 MS without T2DM, 171 T2DM without MS, 256 T2DM with MS) whose ages ranged between 40-70 years old. Significant differences in continuous variables among subject groups were confirmed by ANCOVA or MANCOVA test using 1,000 stratified bootstrap samples with bias corrected and accelerated (BCa) 95% CI. Spearman's rho rank correlation test was used to test the correlation between two variables.

Results

The AR index was formulated as 1+log₁₀(R₀)-log₁₀(A₀). The AR index was more strongly associated with increased risk of T2DM and MS than hypoadiponectinemia and hyperresistinemia alone. The AR index was more strongly correlated with the insulin resistance indexes and key metabolic endpoints of T2DM and MS than adiponectin and resistin levels alone. The AR index was also correlated with a higher number of MS components than adiponectin and resistin levels alone. The IR_AR index was formulated as log₁₀(I₀G₀)+log₁₀(I₀G₀)log₁₀(R₀/A₀). The normal reference range of the IR_AR index for insulin sensitive individuals was between 3.265 and 3.538. The minimum cut-off values of the IR_AR index for insulin resistance assessment were between 3.538 and 3.955.

Conclusions

The novel AR and IR_AR indexes are cost-effective, precise, reproducible and reliable integrated diagnostic biomarkers of insulin sensitivity for screening subjects with increased risk of future development of T2DM and MS.

Adiposity and insulin resistance correlate with telomere length in middle-aged Arabs: the influence of circulating adiponectin

OBJECTIVE

Studies in obesity have implicated adipocytokines in the development of insulin resistance, which in turn may lead to accelerated aging. In this study, we determined associations of chromosomal telomere length (TL) to markers of obesity and insulin resistance in middle-aged adult male and female Arabs with and without diabetes mellitus type 2 (DMT2).

DESIGN AND METHODS

One hundred and ninety-three non-diabetic and DMT2 subjects without complications (97 males and 96 females) participated in this cross-sectional study. Clinical data, as well as fasting blood samples, were collected. Serum glucose and lipid profile were determined using routine laboratory methods. Serum insulin, leptin, adiponectin, resistin, tumor necrosis factor-α, and PAI-1 were quantified using customized multiplex assay kits. High sensitive C-reactive protein (hsCRP) and angiotensin II (ANG II) were measured using ELISAs. Circulating leukocyte TL was examined by quantitative real-time PCR.

RESULTS

Circulating chromosomal leukocyte TL had significant inverse associations with body mass index (BMI), systolic blood pressure, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), low-density lipoprotein (LDL)- and total cholesterol, ANG II and hsCRP levels. Adiponectin, BMI, systolic blood pressure, and LDL cholesterol predicted 47% of the variance in TL (P<0.0001). HOMA-IR was the most significant predictor for TL in males, explaining 35% of the variance (P=0.01). In females, adiponectin accounted for 28% of the variance in TL (P=0.01).

CONCLUSION

Obesity and insulin resistance are associated with chromosomal TL among adult Arabs. Evidence of causal relations needs further investigation. The positive association of adiponectin to TL has clinical implications as to the possible protective effects of this hormone from accelerated aging.

A 12-week regimen of caloric restriction improves levels of adipokines and pro-inflammatory cytokines in Korean women with BMIs greater than 23 kg/m2

INTRODUCTION

Adipose tissue mass (ATM) is an important source of adipokines. Increases in ATM contribute to chronic low-grade inflammation characterized by high levels of pro-inflammatory cytokines. We investigated the effects of body fat reduction on blood levels of adipokines and pro-inflammatory cytokines in Korean women with BMIs >23 kg/m(2).

METHODS

A total of 46 healthy women participated in the study. A registered dietician supervised the subjects as they conformed to a program of caloric restriction during a 12-week experimental period. Anthropometric assessments were carried out, and blood levels of lipids, adipokines, and pro-inflammatory cytokines were analyzed at the beginning and the end of the experiment.

RESULTS

Body weight and body fat mass decreased significantly in our subjects after 12 weeks of caloric restriction (p < 0.001). Blood levels of triacylglycerol were significantly reduced in accordance with body fat reduction. However, the other blood lipid parameters were unchanged. Adipokine, leptin, and visfatin levels decreased significantly, while adiponectin increased significantly (p < 0.05). Levels of pro-inflammatory cytokines TNF-alpha and IFN-gamma were significantly reduced (p < 0.05).

CONCLUSIONS

Our results indicate that body fat reduction via caloric restriction positively affects the blood levels of adipokines and pro-inflammatory cytokines.

Patients with nonalcoholic fatty liver disease display increased serum resistin levels and decreased adiponectin levels

AIM

Resistin and adiponectin are recently discovered protein hormones, which are produced and secreted by adipocytes. Nonalcoholic fatty liver disease (NAFLD) is a metabolic syndrome, which is associated with obesity. The aim of this study was to evaluate the changes of serum adiponectin and resistin in patients with NAFLD and to determine the relationship between serum adipokine levels and clinicopathologic parameters of NAFLD.

METHODS

Forty-three patients with NAFLD and 43 controls were enrolled in this pair-matched study. Body weight, height, body mass index, abdominal wall fat thickness, waist circumference, hip circumference, and the percentage of body fat were measured. Additionally, serum lipid, glucose, alanine aminotransferase, aspartate aminotransferase, adiponectin, and resistin were determined in all individuals. Serum adiponectin and resistin levels were determined using ELISA kits.

RESULTS

Serum adiponectin levels were significantly lower in patients with NAFLD compared to the control group (control: 2.01+/-1.10 mg/l vs. NAFLD: 1.38+/-0.65 mg/l, P<0.01). Serum resistin levels were significantly elevated in patients with NAFLD compared to the control group (control: 4.70+/-3.30 ng/ml vs. NAFLD: 9.20+/-7.20 ng/ml, P<0.05). Serum adiponectin concentration was negatively correlated with the waist circumference (rho=-0.425), body mass index (rho=-0.329), percentage of body fat (rho=-0.256), abdominal wall fat thickness (rho=-0.226), and fasting blood glucose concentration (rho=-0.242), but was positively correlated with HDL (rho=0.226). Serum resistin concentration was positively correlated with waist circumference (rho=0.237). No correlation was found between resistin levels and blood pressure, fasting blood glucose concentration, triglyceride, total cholesterol, and HDL.

CONCLUSION

NAFLD patients had lower adiponectin levels and higher resistin levels. A positive correlation was found between resistin and waist circumference, whereas a negative correlation was found between adiponectin and waist circumference, body mass index, percentage of body fat, abdominal wall fat thickness, and fasting blood glucose concentration. These data suggested that hypoadiponectinemia and hyperresistinemia might be involved in the development of NAFLD.

Statin therapy in South Asians-facts and future

South Asians have higher overall burden of coronary heart disease. South Asian migrants suffer from more severe and fatal coronary heart disease at younger age despite similar risk factors compared with local population. Elevated blood cholesterol contributes to atherosclerosis and heart disease and is one of the primary modifiable risk factor for these conditions. Since the discovery of a fungal metabolite that inhibits 3-hydroxy-3methyl-glutaryl-coenzyme A reductase, statins have emerged rapidly as the global leader in medical therapeutics designed to lower low-density lipoprotein cholesterol and had reduced mortality and morbidity from coronary heart disease when used for primary or secondary prevention. Despite the considerable burden imposed by cardiovascular disease, South Asians remain inadequately targeted for risk-reduction strategies, including screening and treatment for dyslipidemia.

Globular adiponectin augments insulin secretion from pancreatic islet beta cells at high glucose concentrations

Adiponectin plays an important role in improving insulin resistance and preventing atherosclerosis. However it has been rarely reported that adiponectin influences insulin secretion because its receptor was identified in human islet beta cells. In order to investigate the direct effect of adiponectin on pancreatic islet beta cells, we performed an insulin secretion test in purified rat islets, which were incubated with adiponectin (100 ng/mL) at low (3.3 mM) and high (16.7 mM) glucose concentrations. Furthermore, cell lysates were extracted from the adiponectin-treated islets for p-AMPKalpha assay. RTPCR and immunohistochemical examination showed both adiponectin receptor 1 (AdipoR1) and receptor 2 (AdipoR2) were expressed in islet cells and AdipoR1 was predominantly expressed. Insulin secretion was significantly increased in the presence of adiponectin for 6 h at high glucose concentration. Meanwhile, the levels of phosphorylated AMPK increased with adiponectin treatment at high glucose concentrations. It is concluded that adiponectin augments insulin secretion from pancreatic islet beta cells at high glucose concentration through AMPK activation.

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.