Decreased expression of apM1 in omental and subcutaneous adipose tissue of humans with type 2 diabetes

Cutaneous changes in diabetic patients: Primed for aberrant healing?

Cutaneous manifestations affect most patients with diabetes mellitus, clinically presenting with numerous dermatologic diseases from xerosis to diabetic foot ulcers (DFUs). Skin conditions not only impose a significantly impaired quality of life on individuals with diabetes but also predispose patients to further complications. Knowledge of cutaneous biology and the wound healing process under diabetic conditions is largely limited to animal models, and studies focusing on biology of the human condition of DFUs remain limited. In this review, we discuss the critical molecular, cellular, and structural changes to the skin in the hyperglycaemic and insulin-resistant environment of diabetes with a focus specifically on human-derived data. Elucidating the breadth of the cutaneous manifestations coupled with effective diabetes management is important for improving patient quality of life and averting future complications including wound healing disorders.

Intermittent fasting and exercise therapy abates STZ-induced diabetotoxicity in rats through modulation of adipocytokines hormone, oxidative glucose metabolic, and glycolytic pathway

Diabetes is a global, costly, and growing public health issue. Intermittent fasting (IF) and exercise therapy have been shown to improve insulin sensitivity (IS) in large studies, although the underlying processes are still unknown. The goal of this study, which included both nondiabetic and diabetic rats, was to look at the mechanisms of intermittent fasting and exercise in the management of diabetotoxicity. The effects of starvation and honey on the oral glucose tolerance test, insulin tolerance test, adipocytokines, oxidative glucose metabolic enzymes, glycolytic enzymes, food intake, and body weight in rats with streptozotocin‐induced diabetes were also investigated. In the nondiabetic phase, rats were administered an oral regimen of distilled water (0.5 ml/rat), honey (1 g/kg body weight), and interventions with IF, and starvation for 4 weeks while in the diabetic phase, after STZ or citrate buffer injections, interventions with IF, exercise, starvation, and honey treatment began for 4 weeks. At all OGTT and ITT points, there was a substantial rise in glucose in the STZ group. Adipocytokines hormone, oxidative glucose metabolic enzymes, glycolytic enzymes, and body weight were all affected by STZ when compared to starvation and honey, however, IF and exercise significantly reduced these alterations. In diabetic rats, intermittent fasting and exercise enhanced serum adipocytokines levels. These findings imply that adipokines modulate glycolytic/nonmitochondrial enzymes and glucose metabolic/mitochondrial dehydrogenase to mediate the antidiabetic effects of intermittent fasting and exercise.

Intermittent fasting and exercise therapy abates STZ‐induced diabetotoxicity in rats through modulation of adipocytokines hormone, oxidative glucose metabolic, and glycolytic pathway.

Leptin Receptor (rs1137101) and Brain-Derived Neurotrophic Factor (rs925946) Gene Variants Are Associated with Obesity in the Early- but Not in the Late-Onset Population of Hungarian Psoriatic Patients

Background: Psoriatic patients have considerably higher odds of being obese compared with the general population; however, the exact pathophysiological link between psoriasis and obesity needs to be elucidated. Methods: To investigate the association of psoriasis with established obesity-related gene variants, we conducted a population-based case-control study including 3541 subjects (574 psoriasis cases and 2967 controls from the general Hungarian population). Genotyping of 20 SNPs at ADIPOQ, BDNF, FTO, GNPDA2, LEPR, MC4R, NEGR1, NPY, PPARG, TMEM18, and UCP2 were determined, and differences in genotype and allele distributions were investigated. Multiple logistic regression analyses were implemented. Results: Analysis revealed an association between the G allele of the rs1137101 polymorphism (LEPR gene) and obesity risk (OR: 3.30 (1.45; 7.50), p = 0.004) in the early-onset group of psoriatic patients. Furthermore, the T allele of rs925946 polymorphism (BDNF gene) was also associated with increased risk of obesity in early-onset psoriasis (OR: 2.26 (1.24; 4.14), p = 0.008). Conclusions: Our results suggest that in psoriatic patients, there are prominent differences in the causes of obesity that should be accounted for, including not only environmental factors but also patient characteristics, such as the time of disease onset as well as genetic factors.

Novel therapeutic intervention of coenzyme Q10 and its combination with pioglitazone on the mRNA expression level of adipocytokines in diabetic rats

AIMS

Aim of the present study was to investigate the effect of co-administration coenzyme Q10 and pioglitazone on the mRNA expression of adipocytokines in white adipose tissues of chemically induced type 2 diabetes mellitus in rats.

MAIN METHODS

Diabetes was induced by administration of streptozotocin (65 mg/kg, i.p.), followed by nicotinamide (110 mg/kg, i.p.) 15 min later. The diabetic rats were treated coenzyme Q10 (Q10, 10 mg/kg, p.o.) or pioglitazone (PIO, 20 mg/kg, p.o.) alone and their combination for four weeks. Biochemical parameters like FBS level, insulin and HbA1c along with tissue levels of MDA, SOD, CAT and GSH were estimated. The mRNA levels of ADIPOQ, RBP4, RETN, IL-6 and TNF-α in White Adipose Tissue (WAT) were measured.

KEY FINDINGS

Treatment with Q10 + PIO showed a significant reduction in the levels of FBS, HbA1c and a significant increase in insulin levels as compared to normal control group. Additionally, there was a significant change in the levels of biomarkers of oxidative stress after treatment with Q10 + PIO as compared to streptozotocin-nicotinamide group. Treatment with Q10 + PIO also significantly altered the mRNA expression of ADIPOQ, RETN, IL-6 and TNF-α when compared to monotherapy. However, mRNA expression of RBP4 did not alter in Q10 + PIO treated animal as compared to Q10 or PIO alone.

SIGNIFICANCE

It is concluded that co-administration of Q10 and PIO has been shown the better therapeutic effect on the mRNA expression of adipocytokines and oxidative stress parameters as compared to either Q10 or PIO.

Inflammatory markers in children and adolescents with type 2 diabetes mellitus

This review examines the potential relationship between serum inflammation markers and type 2 diabetes mellitus (T2DM). Inflammation markers have been proposed as prognostic markers for the development of T2DM and its complications. Furthermore, modulation of the inflammatory process may offer future treatment strategies for T2DM. This review focuses on children and adolescents because there is usually little, if any, complications associated with other disease processes, use of medications, or active tobacco smoking. Furthermore, β-cell failure in young age cannot be solely explained by aging and exhaustion of β-cells due to insulin resistance. Pediatric studies have demonstrated that pro-inflammatory cytokines TNF-α, IL-6, IL-1β, IFNγ, PEDF, and fetuin A were increased in insulin resistance, while the anti-inflammatory cytokines adiponectin and omentin were decreased. Furthermore, TNF-α, fetuin A, FGF-21 were altered in obese children with T2DM suggesting a direct involvement in β-cell failure. Future studies focusing on children and adolescents may facilitate our understanding of T2DM as an inflammatory disease process.

Connecting Metainflammation and Neuroinflammation Through the PTN-MK-RPTPβ/ζ Axis: Relevance in Therapeutic Development

Inflammation is a common factor of pathologies such as obesity, type 2 diabetes or neurodegenerative diseases. Chronic inflammation is considered part of the pathogenic mechanisms of different disorders associated with aging. Interestingly, peripheral inflammation and the associated metabolic alterations not only facilitate insulin resistance and diabetes but also neurodegenerative disorders. Therefore, the identification of novel pathways, common to the development of these diseases, which modulate the immune response and signaling is key. It will provide highly relevant information to advance our knowledge of the multifactorial process of aging, and to establish new biomarkers and/or therapeutic targets to counteract the underlying chronic inflammatory processes. One novel pathway that regulates peripheral and central immune responses is triggered by the cytokines pleiotrophin (PTN) and midkine (MK), which bind its receptor, Receptor Protein Tyrosine Phosphatase (RPTP) β/ζ, and inactivate its phosphatase activity. In this review, we compile a growing body of knowledge suggesting that PTN and MK modulate the immune response and/or inflammation in different pathologies characterized by peripheral inflammation associated with insulin resistance, such as aging, and in central disorders characterized by overt neuroinflammation, such as neurodegenerative diseases and endotoxemia. Evidence strongly suggests that regulation of the PTN and MK signaling pathways may provide new therapeutic opportunities particularly in those neurological disorders characterized by increased PTN and/or MK cerebral levels and neuroinflammation. Importantly, we discuss existing therapeutics, and others being developed, that modulate these signaling pathways, and their potential use in pathologies characterized by overt neuroinflammation.

Antidiabetic Effect of Monolluma quadrangula Is Mediated via Modulation of Glucose Metabolizing Enzymes, Antioxidant Defenses, and Adiponectin in Type 2 Diabetic Rats

Monolluma quadrangula is a succulent bush traditionally used to treat diabetes and peptic ulcer. The present study aimed to investigate the effect of M. quadrangula hydroethanolic extract on glucose tolerance, insulin sensitivity, glucose metabolizing enzymes, lipid profile, and adiponectin expression in type 2 diabetic rats. In addition, the study evaluated the antioxidant and anti-inflammatory activities of the M. quadrangula extract. Type 2 diabetes was induced by feeding rats a high-fat diet (HFD) for 8 weeks followed by 30 mg/kg streptozotocin (STZ). Diabetic rats received 300 or 600 mg/kg M. quadrangula extract for 4 weeks. HFD/STZ diabetic rats showed impaired glucose tolerance, reduced insulin secretion, and insulin resistance. HFD and STZ induced a significant increase in serum cholesterol, triglycerides and proinflammatory cytokines, and liver lipid peroxidation. Treatment with M. quadrangula extract ameliorated these metabolic disturbances and increased liver glycogen, hexokinase activity, and antioxidants. M. quadrangula declined the activity of liver glucose-6-phosphatase and fructose-1,6-biphosphatase. In addition, M. quadrangula extract increased serum adiponectin levels and hepatic adiponectin expression in HFD/STZ diabetic rats. In conclusion, M. quadrangula exerts antidiabetic effect mediated via ameliorating glucose tolerance, insulin sensitivity, glucose metabolizing enzymes, and antioxidant defenses. Increased adiponectin levels and expression seems to mediate, at least in part, the antidiabetic effect of M. quadrangula.

Inflammation Markers in Type 2 Diabetes and the Metabolic Syndrome in the Pediatric Population

PURPOSE OF REVIEW

Chronic inflammation, adipokines, and hepatokines have been identified as basis of insulin resistance and β cell failure in animal models. We present our current knowledge concerning the potential relationship between these cytokines, inflammation, metabolic syndrome (MetS), and type 2 diabetes mellitus (T2DM) in the pediatric population.

RECENT FINDINGS

Pro-inflammatory cytokines related to insulin resistance and MetS in children are tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-1β, interferon gamma, pigment epithelium-derived factor, chemerin, vaspin, and fetuin A. Anti-inflammatory cytokines associated with insulin resistance and MetS in children are leptin, adiponectin, omentin, fibroblast growth factor (FGF)-21, osteocalcin, and irisin. These anti-inflammatory cytokines are decreased (adiponectin, omentin, and osteocalcin) or increased (leptin, FGF-21, and irisin) in obesity suggesting a resistance state. TNF-α, fetuin A, and FGF-21 are altered in obese children with T2DM suggesting an involvement in β cell failure. These cytokines, adipokines, and hepatokines may be able to predict development of MetS and T2DM and have a potential therapeutic target ameliorating insulin resistance.

Hypoadiponectemia is associated with metabolic syndrome in patients with type 2 diabetes

Adipose tissue-expressed adiponectin levels are inversely related to the degree of adiposity, and a reduction in adiponectin serum levels is accompanied by insulin resistance. The aim of this study was to evaluate the relationship between serum adiponectin concentration and metabolic syndrome (MetS) in patients with type 2 diabetes mellitus (DM). Fasting blood samples were obtained from 150 volunteers with type 2 DM. MetS and its components were defined according to diagnostic criteria from the International Diabetes Federation. Serum adiponectin concentrations were measured using a commercially available enzyme-linked immunosorbent assay. Among the 150 patients with type 2 DM, 102 (68.0%) had MetS. Female gender (P = 0.007), hypertension (P = 0.005), systolic blood pressure (P < 0.001), diastolic blood pressure (DBP, P < 0.001), waist circumference (P < 0.001), body weight (P < 0.001), body mass index (BMI, P < 0.001), fasting glucose (P = 0.035), triglyceride (TG) level (P < 0.001), glycated hemoglobin level (HbA1c, P = 0.020), insulin level (P < 0.001), and homeostasis model assessment of insulin resistance (HOMA-IR, P < 0.001) were higher in DM patients who had MetS, whereas high-density lipoprotein cholesterol (HDL-C) concentrations (P < 0.001) and adiponectin levels (P < 0.001) were lower. Univariate linear analysis revealed that logarithmically transformed age (log-age, r = 0.279; P = 0.001) and HDL-C (r = 0.246; P = 0.002) positively correlated, whereas height (r = -0.183; P = 0.025), body weight (r = -0.282; P < 0.001), BMI (r = -0.237; P = 0.004), waist circumference (r = -0.249; P = 0.002), DBP (r = 0.252; P = 0.002), log-TG (r = 0.255; P = 0.002), log-insulin (r = -0.298; P < 0.001), and log-HOMA-IR (r = 0.288; P < 0.001) negatively correlated with serum adiponectin levels in patients with type 2 DM. Multivariate forward stepwise linear regression analysis revealed that log-age (adjusted R² change = 0.069; P < 0.001) positively correlated, whereas log-insulin (adjusted R² change = 0.182; P = 0.002) and HDL-C (adjusted R² change = 0.037; P = 0.006) negatively correlated with serum adiponectin levels in patients with type 2 DM. This study showed that lower serum adiponectin levels were positively associated with MetS in patients with type 2 DM and significantly positively related to age but negatively related to serum insulin and HDL-C levels in these subjects.

Are adipocytokines inflammatory or metabolic mediators in patients with inflammatory bowel disease?

This study examined the adiponectin and leptin levels and insulin resistance (IR) in patients with inflammatory bowel disease (IBD) and the associations between these factors and IBD characteristics. Fasting serum leptin, adiponectin, glucose, and insulin levels, as well as inflammatory parameters, were measured in 105 patients with IBD (49 patients with Crohn’s disease [CD], 56 patients with ulcerative colitis [UC]) and 98 healthy controls [HC]. IR was evaluated using the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR). Disease activity and severity in patients with UC were evaluated using the Truelove–Witts index, and patients with CD were evaluated using the Crohn’s Disease Activity Index. Serum adiponectin levels were found to be significantly lower in patients with CD and UC (p<0.001). Serum leptin levels were also found to be significantly higher in both the UC and CD groups (p<0.001). When HOMA-IR levels were compared, no significant difference was detected for either the CD or UC groups compared with the controls. In conclusion, it was shown that leptin levels increased and adiponectin levels decreased in patients with IBD, which is thought to be related to chronic inflammation. The effects of adipocytokines in patients with IBD with inflammatory and metabolic processes need to be investigated in further broader studies.

New insight into inter-organ crosstalk contributing to the pathogenesis of non-alcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver dysfunction and a significant global health problem with substantial rise in prevalence over the last decades. It is becoming increasingly clear that NALFD is not only predominantly a hepatic manifestation of metabolic syndrome, but also involves extra-hepatic organs and regulatory pathways. Therapeutic options are limited for the treatment of NAFLD. Accordingly, a better understanding of the pathogenesis of NAFLD is critical for gaining new insight into the regulatory network of NAFLD and for identifying new targets for the prevention and treatment of NAFLD. In this review, we emphasize on the current understanding of the inter-organ crosstalk between the liver and peripheral organs that contributing to the pathogenesis of NAFLD.

Adiponectin/TNF-α Ratio Following a Selected Aerobic Training in Sedentary Adult Obese Men

Background: Based on clinical studies, low adiponectin and high tumor necrosis factor alpha (TNF-α) are associated with obesity and related diseases such as type 2 diabetes and insulin resistance. Objectives: In this study, we aimed to investigate the effect of an aerobic training program on adiponectin, TNF-α, and adiponectin/TNF-α ratio in adult obese men. Patients and Methods: For this purpose, 24 sedentary adult obese men matched for age (38 ± 3.23 years) and body mass index (31.94 ± 3.26 kg/m2 ) were selected and divided into exercise (aerobic training) and control groups. Exercise subjects participated in an aerobic exercise training intervention for 12 weeks (3 times/week) and the control group did not participate in aerobic intervention. Anthropometric and biochemical data including fasting serum adiponectin, TNF-α, and adiponectin/TNF-α ratio were measured before and after aerobic training for each participant in each group. Data were analyzed by both independent and paired sample t test. Results: Compared to pre-training, fasting serum adiponectin decreased significantly (P = .019), but serum TNF-α was not changed by aerobic training (P = .057). A significant increase was observed in adiponectin/TNF-α ratio in exercise subjects after aerobic training (P = .008). Conclusions: Based on these data, we conclude that aerobic training intervention is associated with improved inflammatory profile in obese subjects.

Anti-obesity effect of ethanolic extract from Cosmos caudatus Kunth leaf in lean rats fed a high fat diet

Background

Obesity is a major health concern both in developed and developing countries. The use of herbal medicines became the subject of interest for the management of obesity due to its natural origin, cost effectiveness and minimal side effects. The present study aimed at investigating anti-obesity potential of ethanolic extract from Cosmos caudatus Kunth leaf (EECCL).

Methods

In this study, the rats were randomly divided into six groups i.e., (1) Normal Diet (ND); (2) Normal Diet and 175 mg/kgBW of EECCL (ND + 175 mg/kgBW); (3) Normal Diet and 350 mg/kgBW of EECCL (ND + 350 mg/kgBW); (4) High Fat Diet (HFD); (5) High Fat Diet and 175 mg/kgBW of EECCL (HFD + 175 mg/kgBW); (6) High Fat Diet and 350 mg/kgBW of EECCL (HFD + 350 mg/kgBW). The anti-obesity potential was evaluated through analyses of changes in body weight, visceral fat weight, and blood biochemicals including total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), leptin, insulin, adiponectin, ghrelin and fecal fat content. In addition, metabolite profiling of EECCL was carried out using NMR spectroscopy.

Results

Rats receiving EECCL together with HFD showed significant (p < 0.05) reduction in body weight gain compared to rats receiving HFD only. At the end of study, the body weight gain of EECCL treated rats was not significantly (p > 0.05) different with those of ND rats. Other related obesity biomarkers including plasma lipid profiles, insulin, leptin, ghrelin and adiponectin levels also showed significant improvement (p < 0.05). Administration of EECCL caused significant (p < 0.05) increase in fecal fat excretion, which validates the hypothesis of lipase inhibition, an anti-obesity mechanism similar to standard drug of Orlistat. The ¹H-NMR spectra of EECCL ascertained the presence of catechin, quercetin, rutin, kaempherol and chlorogenic acid in the extract.

Conclusion

Conclusively, EECCL showed anti-obesity properties by inhibition of intestinal lipid absorption and modulation of adipocytes markers.

Leptin but not adiponectin is related to type 2 diabetes mellitus in obese adolescents

BACKGROUND

Adipokines have been suggested to be involved in the development of type 2 diabetes mellitus (T2DM). However, studies in humans are controversial and analyzes at the onset of disease are scarce.

METHODS

We compared adiponectin and leptin levels between 74 predominately Caucasian adolescents with T2DM and 74 body mass index (BMI)-, age-, and gender-matched controls without T2DM. Adiponectin and leptin were correlated to age, BMI, hemoglobin A1c (HbA1c), blood pressure, and lipids.

RESULTS

Adolescents with T2DM showed significant lower leptin levels as compared with controls (18 ± 12 vs. 37 ± 23 ng/mL, p < 0.001), whereas the adiponectin levels did not differ between the adolescents with and without T2DM (5.0 ± 2.5 vs. 4.9 ± 2.5 µg/mL, p = 0.833). The associations between adiponectin and high-density lipoprotein (HDL) cholesterol (r = 0.42), systolic (r = -0.15), and diastolic blood pressure (r = -0.20) were stronger as the associations of leptin to these parameters (all r < 0.07). In multiple linear regression analysis, leptin was significantly and positively associated with BMI [β-coefficient: 1.3 (95% confidence interval (95% CI): ±0.5), p < 0.001] and female sex [β-coefficient: 9.7 (95% CI: ±6.7), p = 0.005], and negatively with age [β-coefficient: -2.3 (95% CI: ±2.1), p < 0.001] and HbA1c [β-coefficient -3.1 (95% CI: ±2.1), p = 0.011]. Adiponectin was not significantly associated with BMI, HbA1c, age, or gender in multiple linear regression analysis.

CONCLUSIONS

Because adiponectin levels did not differ between obese adolescents with and without T2DM, hypoadiponectinemia as observed in obesity seems not to be involved in the genesis of T2DM. The relative hypoleptinemia in obese adolescents with T2DM as compared with obese adolescents without T2DM may contribute to the development of T2DM. Future longitudinal studies in humans are necessary to prove this hypothesis.

Spirulina versicolor improves insulin sensitivity and attenuates hyperglycemia-mediated oxidative stress in fructose-fed rats

Aim:

The current study aimed to investigate the anti-hyperglycemic, anti-hyperlipidemic and insulin sensitizing effects of the cyanobacterium Spirulina versicolor extract in fructose-fed rats.

Materials and Methods:

Rats were fed 30% fructose solution in drinking water for 4 weeks. Animals exhibited hyperglycemia and hyperinsulinemia were selected for further investigations. Diabetic and control rats were orally supplemented with 50 mg/kg body weight S. versicolor extract for 4 weeks.

Results:

At the end of 8 weeks, fructose-fed rats showed a significant increase in serum glucose, insulin, cholesterol, triglycerides, cardiovascular risk indices and insulin resistance. Treatment of the fructose-fed rats with S. versicolor extract improved this metabolic profile. Fructose feeding produced a significant increase in serum tumor necrosis factor alpha and a decrease in adiponectin levels. In addition, fructose-fed rats exhibited a significant increase in liver, kidney and heart lipid peroxidation levels, and declined antioxidant defenses. Supplementation of the fructose-fed rats with S. versicolor extract reversed these alterations.

Conclusion:

S. versicolor attenuates hyperglycemia-mediated oxidative stress and inflammation, and is thus effective in improving insulin sensitivity in fructose-fed rats.

Association of polymorphisms of the ADIPOQ, ADIPOR1 and ADIPOR2 genes with type 2 diabetes mellitus

The study of hereditary predisposition to multifactorial diseases is essential for diagnosis and selection of the optimal treatment. The study of polymorphisms of candidate genes whose products are involved in the pathogenesis of multifactorial diseases is of great clinical importance. Aim. The aim of this study was to investigate the association of rs2241766 and rs1501299 polymorphisms in the ADIPOQ gene, rs2275737 and rs2275738 polymorphisms in the ADIPOR1 gene and rs11061971 and rs16928751 polymorphisms in the ADIPOR2 gene with the development of type 2 diabetes mellitus (T2DM) in the Russian population. Materials and methods. The study included a group of 500 patients with T2DM diagnosed based on standard diagnostic criteria (T2DM+). The control group (T2DM-) was a random sample of 500 patients with no evidence of the disease and was matched to the T2DM+ group for gender, age and body mass index. The determination of alleles and genotypes was performed using real-time polymerase chain reaction with TaqMan probes. The X2 test and contingency tables were used to compare the distribution of allele and genotype frequencies. A p-value of

Subcutaneous and total fat at L4-L5 and subcutaneous, visceral and total fat at L3-L4 are important contributors of fasting and postprandial adiponectin levels

OBJECTIVES

Insulin resistance and central obesity have been implicated in the pathogenesis of hypoadiponectinemia in obesity. The aim of this study is to evaluate circulating post-prandial adiponectin in relation to glucose and insulin metabolism, indexes of insulin resistance and sensitivity and, indexes of body fat accumulation and distribution in obese men.

METHODS

Twenty-eight non-diabetic men underwent an OGTT followed by an oral fat load and were studied at baseline and for 5 h post-prandially for serum adiponectin, glucose and insulin. Insulin resistance was estimated by Homeostasis model assessment (HOMA) and insulin sensitivity by Matsuda index. Body fat accumulation and distribution were evaluated by anthropometric indexes and multiple slices MRI of the abdomen and hip.

RESULTS

Adiponectin was negatively correlated to insulin levels. Fasting and area under the curve (AUC) adiponectin levels were negatively correlated to HOMA (both p < 0.01) and positively to Matsuda index (both p < 0.05). Negative correlations between fasting adiponectin and total fat (r = -0.408, p < 0.05), AUC adiponectin and subcutaneous, visceral and total fat (r = -0.375, -0.413 and -0.475 respectively, all p < 0.05) at L3-L4 were found, and negative correlations between fasting adiponectin and subcutaneous (r = -0.402, p < 0.05) and total fat (r = -0.491, p < 0.05) and between AUC adiponectin and subcutaneous and total fat (r = -0.506 and -0.547, respectively, both p < 0.01) were present at L4-L5.

CONCLUSIONS

Circulating adiponectin is inversely correlated to both visceral and subcutaneous fat in non-diabetic men, implying that both compartments are important for adiponectin levels. The best correlation is found at measurement site L4-L5.

Antidiabetic effect of the α-lipoic acid γ-cyclodextrin complex

In recent years, the number of patients suffering from diabetes mellitus has been increasing worldwide. In particular, type 2 diabetes mellitus, a lifestyle-related disease, is recognized as a serious disease with various complications. Many types of pharmaceutics or specific health foods have been used for the management of diabetes mellitus. At the same time, the relationship between diabetes mellitus and α-lipoic acid has been recognized for many years. In this study, we found that the α-lipoic acid γ-cyclodextrin complex exhibited an HbA_1c lowering effect for treating type 2 diabetes mellitus in animal models. Moreover, in this study, we investigated the activation of phosphorylation of AMP-activated protein kinase, which plays a role in cellular energy homeostasis, in the liver of KKA^y mice by using α-lipoic acid and the α-lipoic acid γ-cyclodextrin complex. Our results show that the α-lipoic acid γ-cyclodextrin complex strongly induced the phosphorylation of AMP-activated protein kinase. Thus, we concluded that intake of the α-lipoic acid γ-cyclodextrin complex exerted an antidiabetic effect by suppressing the elevation of postprandial hyperglycemia as well as doing exercise.

Adiponectin as a new paradigm for approaching Alzheimer's disease

Adiponectin is an adipocytokine released by the adipose tissue and has multiple roles in the immune system and in the metabolic syndromes such as cardiovascular disease, Type 2 diabetes, obesity and also in the neurodegenerative disorders including Alzheimer's disease. Adiponectin regulates the sensitivity of insulin, fatty acid catabolism, glucose homeostasis and anti-inflammatory system through various mechanisms. Previous studies demonstrated that adiponectin modulates memory and cognitive impairment and contributes to the deregulated glucose metabolism and mitochondrial dysfunction observed in Alzheimer's disease. Here, we aim to summarize recent studies that suggest the potential correlation between adiponectin and Alzheimer's disease.

The combined effects of physical exercise training and detraining on adiponectin in overweight and obese children

Background

The purpose of this study is to assess the combined exercise programs (12 weeks' physical exercise training, resistance and aerobic) and 6 weeks' detraining on the correlation of metabolic syndrome (MS) markers and plasma adiponectin level in two groups.

Methods

Participants were divided into two groups [physical exercise training group (EG, n = 8) and control group (CG, n = 7)]. The EG performed a 12-week training program (aerobic and resistance training twice/wk, more than 40 min/d). After 12 weeks' exercise training and 6 weeks' detraining, we also evaluated MS markers and plasma adiponectin at three time periods (baseline, EBP; 12 weeks' exercise program, 12 EP; 12 weeks' and 6 weeks' detraining, 12 + 6 EDP) in overweight and obese children.

Results

Compared with the CG, After the 12 weeks' exercise treatment, weight, body mass index (BMI), waist girth, percent body fat, lean body mass (LBM), percentage lean body, systolic blood pressure, and insulin and homeostatic model assessment (HOMA) indices were lowered in the EG, and plasma adiponectin levels were not altered in the EG. After 6 weeks' detraining, insulin, insulin resistance, and plasma adiponectin levels were significantly increased in the EG. In the adiponectin level, there were positive correlations with LBM and percent lean body and negative correlations with percent body fat, insulin, and insulin resistance after 12 weeks' physical exercise intervention and 6 weeks' detraining.

Conclusion

These findings suggest that combined physical training is a useful tool in the management of MS markers in the training periods. Moreover, there was an additive effect even after the 6-weeks detraining period.

Adipocytokines in thyroid dysfunction

Adipocytokines are important mediators of interorgan crosstalk in metabolic regulation. Thyroid diseases have effects on metabolism and inflammation. The mechanism of these effects is not clear. Recently, there are several reports suggesting this interrelation between adipocytokines and thyroid dysfunction. In this review, we summarize this relation according to the literature.

Low serum adiponectin concentrations are associated with insulin sensitivity independent of obesity in Sudanese subjects with type 2 diabetes mellitus

AIMS

Prevalence of Type 2 diabetes mellitus among Sudanese population was found to be 3.4% and associated with high rates of complications and obesity. Different adipocytokines are secreted from adipose tissues, among them adiponectin, which was shown to have insulins ensitizing properties and anti-inflammatory, anti-atherogenic effect. The aim of this study was to characterize type 2 diabetes in Sudanese diabetic subjects and controls in respect to hormones influencing or influenced by glucose metabolism.

METHODS

104 type 2 diabetic patients (45 men and 59 women), and 75 matched control subjects (34 men and 41 women) were studied. Fasting serum samples were used to measure adiponectin, leptin, insulin, proinsulin, ghrelin and glucose. Body mass index, insulin/proinsulin ratio and (HOMA) insulin resistance and beta cell function were also calculated.

RESULTS

Adiponectin serum concentrations were significantly lower in subjects with type 2 diabetes compared with controls subjects (P = 0.002), comparison between males and females did not reach significant levels in both diabetic (P = 0.06) or controls (P = 0.16) groups. In the diabetic group adiponectin correlated positively with serum glucose, negatively with serum proinsulin and HOMA beta cell function (P = 0.03) respectively and serum ghrelin (P = 0.003), but not with BMI, HOMA insulin resistance, insulin or leptin. In controls serum adiponectin correlated negatively with BMI (P = 0.002) but not with other variables.

CONCLUSIONS

The findings of this study suggest that, adiponectin concentrations independent on BMI as a measure of adiposity, were mostly linked to insulin sensitivity and not to insulin resistance in Sudanese type 2 diabetic subjects, where race specific regulation mechanisms or different type 2 diabetes phenotype suggested being a major contributory factor in clarification the findings of this study.

Hydrodynamic delivery of adiponectin and adiponectin receptor 2 gene blocks high-fat diet-induced obesity and insulin resistance

Adiponectin and its receptors are inversely related to the degree of obesity and have been identified as potential therapeutic targets for the treatment of obesity. In this study, we evaluated the effect of hydrodynamic delivery of adiponectin and/or its receptor 2 (adipoR2) genes on controlling the development of obesity and insulin resistance in AKR/J mice fed a high-fat diet. An increase in adiponectin and adipoR2 gene expression by hydrodynamic gene delivery prevented diet-induced weight gain, reduced fat accumulation in liver and adipose tissue, and improved insulin sensitivity. Beneficial effects were seen with reduced gluconeogenesis in the liver and lipogenesis in the liver, white adipose tissue and skeletal muscle. Real-time PCR analysis demonstrated overexpression of adiponectin and adipoR2 significantly suppressed transcription of phosphoenolpyruvate carboxykinase (pepck), glucose-6-phosphatase (g6pase), stearoyl CoA desaturase 1 (scd-1), and fatty acid synthase (fas) gene. Inhibition effects were mediated by activating the AMP-activated protein kinase (AMPK). These results prove that elevation of adiponectin and/or adipoR2 expression via gene transfer is an effective approach in managing obesity epidemics.

Adiponectin mRNA in adipose tissue and its association with metabolic risk factors in postmenopausal obese women

OBJECTIVE

The present study evaluates adiponectin mRNA in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) and also evaluates its association with metabolic risk factors in postmenopausal obese women.

DESIGN

A case control study was carried out on postmenopausal women (n=68), in which 34 were obese and 34 were non-obese. Blood sample, visceral and subcutaneous adipose tissues were obtained. Adiponectin mRNA levels were measured by Real Time-RT PCR.

RESULTS

The mean (± SEM) serum adiponectin (28.39 ± 2.52 vs. 20.56 ± 1.13), VAT (0.362 ± 0.098 vs. 0.048 ± 0.005) and SAT (0.222 ± 0.035 vs. 0.042 ± 0.007) adiponectin mRNA levels were significantly lower (p<0.001) in obese than non-obese. However, the mean VAT and SAT adiponectin mRNA levels were similar (p>0.05) between the groups. Further, the mean glucose and TG levels were significantly (p<0.01 or p<0.001) higher, while HDL was lower (p<0.01) in obese than non-obese. Furthermore, VAT adiponectin mRNA also showed significant (p<0.05) and inverse association with TG, while direct association with HDL and both the associations were independent of BMI and WC (waist circumference).

CONCLUSION

The BMI and WC independent and significant association of VAT adiponectin mRNA with TG and HDL suggest its potential modulatory role in lipid metabolism in postmenopausal obese women.

The cellular and molecular mechanisms by which insulin influences breast cancer risk and progression

Epidemiological studies have related hyperinsulinemia and type 2 diabetes to an increased breast cancer risk, an aggressive and metastatic phenotype, and a poor prognosis. Furthermore, diabetic retinopathy arises from pathological angiogenesis, which is also essential for breast cancer growth and metastasis. Insulin stimulates the proliferation of some human breast cancer cell lines in vitro by mechanisms that use both the phosphatidylinositol-3 kinase and the mitogen-activated protein kinase/Akt signaling pathways; it is also a cell survival (anti-apoptotic) agent and enhances tumor cell migration and invasive capacity. Hyperinsulinemia affects breast cancer cells via the endocrine system, but experimental studies suggest the importance of paracrine mechanisms operating by the effects of insulin on the secretion of adipokines from tumor-associated adipose tissue. In such a system, one adipokine, leptin, has stimulatory paracrine effects on breast cancer cell proliferation and survival, while a second, adiponectin, is inhibitory. Leptin, vascular endothelial growth factor, another insulin-regulated adipokine, and insulin itself also stimulate angiogenesis. Insulin has complex interactions with estrogens: it induces adipose stromal cell aromatase and tumor cell sex steroid hormone receptor expression and suppresses sex hormone-binding globulin, which may enhance estrogen synthesis and bioactivity with consequent promotion of estrogen-dependent breast cancer. All these actions influence the later steps in breast cancer development but genetic studies are also revealing connections between gene abnormalities related to type 2 diabetes and the initiation stage of breast carcinogenesis. Understanding the various mechanisms by which insulin participates in breast cancer cell biology provides opportunities for novel approaches to treatment.

Efficacy and tolerability of a novel herbal formulation for weight management in obese subjects: a randomized double blind placebo controlled clinical study

BACKGROUND

The effect of an herbal formulation LI85008F on weight loss in obese human subjects was evaluated in an 8-weeks randomized, double-blind, placebo-controlled study (Clinical Trial Registration no. ISRCTN37381706). Fifty obese subjects (Body mass index 30 to 40 kg/m², 29.3% male; 70.7% female; ages 27-50 years) were randomized into two groups; placebo (n = 25) and LI85008F formulation (n = 25). The participants received either 900 mg/day of LI85008F formulation in three divided doses or three identical placebo capsules and all of them remained on a calorie-controlled diet (2000 cal/day) and 30 min walking for 5 days a week during the entire duration of the study.

RESULTS AND DISCUSSION

At the end of the trial period, LI85008F supplemented group showed significant net reductions in body weight and Body Mass Index (BMI). The participants who received the herbal formulation, showed reduced fasting blood glucose, LDL, LDL/HDL ratio, and triglycerides. At the end of the study, LI85008F supplementation also provided 21.26% (p = 0.012) increase in serum adiponectin level, compared with the placebo group. No major adverse events were reported by the participants in the study duration. In addition, Adipokine profiling study in 3T3-L1 adipocytes demonstrates that LI85008F modulates key regulatory factors of adipogenic differentiation and insulin sensitivity, such as Adiponectin, Pref-1, and resistin.

CONCLUSION

The herbal formulation LI85008F (Adipromin) is prepared from commonly used medicinal plants extracts, which provides useful and safe application for weight loss in obese humans. It also demonstrates potential promise in controlling healthy blood glucose level in obesity linked type 2 diabetes.

Insulin and Endothelin in the Acute Regulation of Adiponectin in Vivo in Humans

OBJECTIVE

In vitro, insulin and endothelin (ET) both modulate adiponectin secretion from adipocyte cell lines. The current studies were performed to assess whether endogenous ET contributes to the acute action of insulin infusions on adiponectin levels in vivo in humans.

RESEARCH METHODS AND PROCEDURES

We studied 17 lean and 20 obese subjects (BMI 21.8 +/- 2.2 and 34.0 +/- 5.0 kg/m(2), respectively). Hyperinsulinemic euglycemic clamp studies were performed using insulin infusion rates of 10, 30, or 300 mU/m(2) per minute alone or with concurrent infusion of BQ123, an antagonist of type A ET receptors. Circulating adiponectin levels were assessed at baseline and after achievement of steady-state glucose with the insulin infusion.

RESULTS

Adiponectin levels were lower in obese than lean subjects (6.76 +/- 3.66 vs. 8.37 +/- 2.79 microg/mL, p = 0.0148 adjusted for differences across gender). Insulin infusions suppressed adiponectin by a mean of 7.8% (p < 0.0001). In a subset of 13 lean and 14 obese subjects for whom data with and without BQ123 were available, there was no evident effect of BQ123 to modulate clamp-associated suppression of adiponectin (p = 0.16). Surprisingly, there was no evident relationship between steady-state insulin concentrations and adiponectin suppression (r = 0.14, p = 0.30), and again no effect of BQ123 to modify this relationship was seen.

DISCUSSION

Despite baseline differences in adiponectin levels, we observed equal suppression of adiponectin with insulin infusions in lean and obese subjects. ET receptor antagonism with BQ123 did not modulate this effect, suggesting that endogenous ET does not have a role in modifying the acute effects of insulin on adiponectin production and/or disposition.

Lower Serum Adiponectin Levels in African-American Boys

OBJECTIVE

To examine adiponectin, an adipocyte-secreted hormone with anti-inflammatory and insulin-sensitizing effects, in relation to race or gender in younger subjects.

RESEARCH METHODS AND PROCEDURES

The relationship of adiponectin, quantitated by radioimmunoassay, to anthropometric and metabolic factors (fasting insulin, glucose, and leptin) and reproductive hormones was examined in 46 healthy African Americans (25 girls/21 boys) and 40 whites (20 girls/20 boys) ranging in age from 12 to 21 years.

RESULTS

There was no statistical difference in BMI or in BMI percentile among the four groups. Sums of skinfolds, but not skinfold percentile, were significantly lower in boys than girls (p = 0.001 and p = 0.896, respectively), whereas there was no difference between racial groups. Leptin was significantly greater in girls (p = 0.0002). There was no difference in fasting serum glucose, insulin, or homeostasis model assessment score among any of the groups. There was a significant negative univariate relationship between serum adiponectin and both BMI and BMI percentile for the entire group (p = 0.006 and p = 0.005). In a multivariate model, BMI percentile (p = 0.005) and the interaction between race and gender (p = 0.026) were significant predictors of serum adiponectin. In this model, African-American boys had the lowest serum adiponectin level, 37% less than white boys, who had the highest adiponectin levels.

DISCUSSION

Serum adiponectin levels are reduced in young obese subjects (African Americans and whites) and are lower in African-American boys than white boys. A lower adiponectin level in African-American boys may predispose this group to a greater risk of diabetes and cardiovascular disease.

Uncoupling protein-2 (UCP2) gene expression in subcutaneous and omental adipose tissue of Asian Indians: Relationship to adiponectin and parameters of metabolic syndrome

Objective

UCP2 is a mitochondrial membrane transporter expressed in white adipose tissue and involved in regulation of energy balance. In this present study, we examined the depot specific comparison of UCP2 gene expression in different metabolic states, in order to explore the potential role of UCP2 in human obesity and diabetes. We also determined UCP2’s association with adiponectin and insulin resistance with different parameters of the metabolic syndrome.

Methods

Subcutaneous adipose tissue (SAT) and omental adipose tissues (OAT) were obtained from 69 subjects, including 23 non-obese controls, 26 obese and 20 obese T2DM patients. Metabolic syndrome and other clinical features were studied. Adiponectin and UCP2 gene expression was quantitated by Real Time Reverse Transcriptase Polymerase Chain Reaction (RT-PCR).

Results

UCP2 gene expression was significantly reduced in obese and diabetic patients compared with controls. Interestingly, we found that UCP2 gene expression was reduced more in omental fat compared with subcutaneous fat and this effect was observed only in males but not in females. Partial correlation analysis showed significant association with the obesity parameters waist circumference, insulin and HOMA-IR, the lipid parameter triglyceride and the adipokine adiponectin.

Conclusion

Reduced UCP2 gene expression in obese and diabetic patients and its association with obesity parameters and HOMA-IR confirms its role as a candidate gene in the study of obesity and diabetes in our population. Also, its association with triglycerides implicates its role in lipid metabolism. An association between adiponectin and UCP2 gene expression may provide us with an innovative therapeutic strategy to prevent obesity related diseases, like diabetes and CVD.

Parallel down-regulation of FOXO1, PPARγ and adiponectin mRNA expression in visceral adipose tissue of class III obese individuals

OBJECTIVE

Adipose tissue is responsible for secretion of several cytokines that mediate systemic effects on obesity and insulin resistance. Subcutaneous abdominal adipose tissue (SAT) and visceral adipose tissue (VAT) are metabolically different and have differences in their gene expression profile. Our study evaluated the expression of adiponectin, FOXO1, PPARγ, and SIRT1 in VAT and SAT of non-obese and class III obese subjects.

METHODS

The adipose tissue samples were obtained by surgery. Reverse transcripts of studied genes were determined by quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

Comparing the different lipid depots, adiponectin expression was lower only in VAT of obese individuals (p = 0.043); FOXO1 and PPARγ levels were decreased in VAT of both groups. When non-obese and obese were compared, only adiponectin expression was lower in SAT and in VAT of obese subjects (p = 0.004 and p = 0.002, respectively). No difference was found with regard to SIRT1 levels in VAT or SAT in both groups. FOXO1 expression in SAT of obese subjects had a negative correlation with age (r = -0.683; p = 0.029) and triglyceride serum levels (r = -0.794; p = 0.006).

CONCLUSION

The decrease mRNA expression of this genes in VAT, responsible for central adiposity, may be associated with an increased risk of obesity and co-morbidities.

Polymorphism of adiponectin (45T/G) and adiponectin receptor-2 (795G/A) in an Iranian population: relation with insulin resistance and response to treatment with pioglitazone in patients with type 2 diabetes mellitus

Adiponectin, an adipose-derived plasma protein, is reduced in patients with obesity and type 2 diabetes. Thiazolidinediones can increase adiponectin levels and improve insulin sensitivity. This study investigated the associations between type 2 diabetes and two single-nucleotide polymorphisms in the adiponectin (45T/G) and adiponectin receptor-2 gene (795G/A), and investigated whether these genetic variants affect the response to pioglitazone in Iranian patients with type 2 diabetes. We genotyped 128 non-diabetic participants and 101 patients with type 2 diabetes for 45T/G and 795G/A with polymerase chain reaction-restriction fragment length polymorphism assays. Patients were treated with pioglitazone for 12 weeks, after which we compared laboratory parameters in these two groups. Fasting blood sugar differed significantly in individuals with different 795G/A genotypes after pioglitazone treatment (P = 0.009). The mean decrease in insulin/glucose ratio after treatment also differed significantly in individuals with different 45T/G genotypes (P = 0.035). The T allele frequency for 45T/G was 87.11% in controls versus 81.68% in patients (P = 0.071). The TG and GG genotypes were more frequent in patients (P = 0.032). The G allele frequency for 795G/A was 76.17% in controls versus 80.20% in patients (P = 0.179). 795G/A variants were not significantly different between patient and control group. The adiponectin gene 45T/G mutation may be an important determinant of type 2 diabetes in the Iranian population. However, adiponectin 45T/G and adiponectin receptor-2 795G/A polymorphisms were not significantly associated with the response to pioglitazone in our sample.

Adipocytokines: The pied pipers

Even though there have been major advances in therapy, atherosclerosis and coronary artery disease retain their lead as one of the major causes of morbidity and mortality in the first decade of 21(st) century. To add to the woes, we have diabetes, obesity and insulin resistance as the other causes. The adipose tissue secretes several bioactive mediators that influence inflammation, insulin resistance, diabetes, atherosclerosis and several other pathologic states besides the regulation of body weight. These mediators are mostly proteins and are termed "adipocytokines". Adiponectin, resistin, visfatin, retinol binding protein-4 (RBP-4) and leptin are a few such proteins. Adiponectin is a multimeric protein, acting via its identified receptors, AdipoR1 and AdipoR2. It is a potential biomarker for metabolic syndrome and has several antiinflammatory actions. Adiponectin increases insulin sensitivity and ameliorates obesity. Resistin, another protein secreted by the adipose tissue, derived its name due to its involvement in the development of insulin resistance. It plays a role in the pathophysiology of several conditions because of its robust proinflammatory activity mediated through the activation of extracellular signal regulated kinases 1 and 2 (ERK 1/2). In 2007, resistin was reported to have protective effect in ischemia-reperfusion injury and myocyte-apoptosis in the setting of myocardial infarction (MI). RBP-4 is involved in the developmental pathology of type 2 diabetes mellitus and obesity. Visfatin has been described as an inflammatory cytokine. Increased expression of visfatin mRNA has been observed in inflammatory conditions like atherosclerosis and inflammatory bowel disease. Leptin mainly regulates the food intake and energy homeostasis. Leptin resistance has been associated with development of obesity and insulin resistance. Few drugs (thiazolidinediones, rimonabant, statins, etc.) and some lifestyle modifications have been found to improve the levels of adipocytokines. Their role in therapy has a lot in store to be explored upon.

Increased abundance of the adaptor protein containing pleckstrin homology domain, phosphotyrosine binding domain and leucine zipper motif (APPL1) in patients with obesity and type 2 diabetes: evidence for altered adiponectin signalling

AIMS/HYPOTHESIS

The adiponectin signalling pathway is largely unknown, but recently the adaptor protein containing pleckstrin homology domain, phosphotyrosine binding domain and leucine zipper motif (APPL1), has been shown to interact directly with adiponectin receptor (ADIPOR)1. APPL1 is present in C2C12 myoblasts and mouse skeletal muscle, but its presence in human skeletal muscle has not been investigated.

METHODS

Samples from type 2 diabetic, and lean and non-diabetic obese participants were analysed by: immunoprecipitation and western blot; HPLC-electrospray ionisation (ESI)-mass spectrometry (MS) analysis; peak area analysis by MS; HPLC-ESI-MS/MS/MS analysis; and RT-PCR analysis of APPL1 mRNA.

RESULTS

Immunoprecipitation and western blot indicated a band specific to APPL1. Tryptic digestion and HPLC-ESI-MS analysis of whole-muscle homogenate APPL1 unambiguously identified APPL1 with 56% sequence coverage. Peak area analysis by MS validated western blot results, showing APPL1 levels to be significantly increased in type 2 diabetic and obese as compared with lean participants. Targeted phosphopeptide analysis by HPLC-ESI-MS/MS/MS showed that APPL1 was phosphorylated specifically on Ser(401). APPL1 mRNA expression was significantly increased in obese and type 2 diabetic participants as compared with lean participants. After bariatric surgery in morbidly obese participants with subsequent weight loss, skeletal muscle APPL1 abundance was significantly reduced (p < 0.05) in association with an increase in plasma adiponectin (p < 0.01), increased levels of ADIPOR1 (p < 0.05) and increased muscle AMP-activated protein kinase (AMPK) phosphorylation (p < 0.05).

CONCLUSIONS/INTERPRETATION

APPL1 abundance is significantly higher in type 2 diabetic muscle; APPL1 is phosphorylated in vivo on Ser(401). Improvements in hyperglycaemia and hypoadiponectinaemia following weight loss are associated with reduced skeletal muscle APPL1, and increased plasma adiponectin levels and muscle AMPK phosphorylation.

Distribution and genotype frequency of adiponectin (+45 T/G) and adiponectin receptor2 (+795 G/A) single nucleotide polymorphisms in Iranian population

The Adiponectin (ADIPOQ) gene encodes adipose tissue-secreted hormone, Adiponectin, which is secreted to the bloodstream by adipocytes. Adiponectin is a hormone with anti-inflammatory and anti-atherogenic properties and plays a significant role in insulin sensitivity and obesity. The genetic variations in ADIPOQ gene change the circulating adiponectin level and may cause insulin resistance. The aim of the present study is to evaluate the frequency of a common single nucleotide polymorphism (SNP) of ADIPOQ gene (+45T/G) and adiponectin receptor-2 (ADIPOR2) gene (+795G/A) in Iranian population and to correlate these data with other populations. A hundred healthy volunteers were enrolled to identify the genotype of ADIPOQ gene (+45T/G) and ADIPOR2 gene (+795G/A). This was performed by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Genotype frequencies for ADIPOQ (+45T/G) were 0.789 for TT, 0.164 for TG, and 0.0468 for GG. Allelic frequencies were 0.87 and 0.13 for T and G, respectively. Genotype frequencies for ADIPOR2 (+795G/A) were 0.09 for AA, 0.3 for AG, and 0.61 for GG; allelic frequencies were 0.24 for A and 0.76 for G. Comparisons between ADIPOQ and ADIPOR2 polymorphisms in Iranian population with those in other populations showed significant differences.

γ-Oryzanol recovers mouse hypoadiponectinemia induced by animal fat ingestion

Adiponectin is an insulin-sensitizing adipocyte-derived adipokine. The decrease in plasma adiponectin level (hypoadiponectinemia) is involved in the development of insulin resistance and the resulting type 2 diabetes. Our previous studies have demonstrated that γ-oryzanol (ORZ) from rice bran suppressed NF-κB activation and increased adiponectin secretion from adipocyte. In this study, we have evaluated effects of oral administration of animal fat (beef tallow) and palmitate on mouse serum adiponectin level. Oral administrations of beef tallow and palmitate significantly suppressed serum adiponectin levels into around half of the initial level from 48 to 96 h after administration compared with the case of corn oil (P<0.05). Coadministration of ORZ successfully remedied mouse hypoadiponectinemia induced by ingestion of beef tallow and the relative adiponectin levels attained to 1.66±0.23 at 96 h after administration (mean value±s.e., P<0.05). Diverse physiological functions of ORZ in crop bran might be promising us to prevent chronic inflammations in the pathogeneses of the metabolic or insulin resistance syndromes.

Hypoadiponectinemia in obese subjects with type II diabetes: A close association with central obesity indices

BACKGROUND

Adiponectin is an adipocyte secreted protein with important biological functions Hypoadiponectinemia is associated with obesity, insulin resistance, and type II diabetes This study aimed to evaluate serum adiponectin level in obese subjects with type II diabetes and its correlation with metabolic parameters

METHODS

This cross-sectional study was performed on 40 obese subjects with type II diabetes and 40 non-diabetic obese control subjects Fasting lipid profile was measured by the enzymatic methods The NycoCard HbA1c protocol was used to measure HbAlc The Serum adiponectin, insulin and glucose levels were measured using an enzyme immunoassay and glucose oxidase methods respectively

RESULTS

Type II diabetes was associated with hypoadiponectinemia, in both men and women Serum adiponectin level in non-diabetic subjects (6.44 ± 2.47 μg/ml) was significantly higher than diabetics (4.55 ± 1.88 μg/ml) Furthermore, serum adiponectin concentration in females was significantly higher than males in non-diabetics (7.18 ± 2.68 vs 5.61 ± 0.57) and diabetic groups (5.18 ± 2.08 vs 3.99 ± 1.5) There was a negative and significant correlation between serum adiponectin level with waist (r = -0.451, p = 0.003), waist to hip ratio (r = -0.404, p = 0.01) and BMI (r = - 0.322, p = 0.042) and a positive correlation with HDL (r = 0.337, p = 0.034) in non-diabetic group In diabetic group, there was only found a negative correlation between adiponectin and waist size (r = -0.317, p = 0.046)

CONCLUSIONS

Obesity and type II diabetes are associated with low serum adiponectin concentration.

Correlation of adiponectin and leptin with insulin resistance: a pilot study in healthy north Indian population

The increasing incidence of obesity, leading to metabolic complications is now recognized as a major public-health problem. Insulin resistance is a central abnormality of the metabolic syndrome, or syndrome X, originally hypothesized by Reaven Insulin resistance is more strongly linked to intra abdominal fat than to fat in other depots. Adipose tissue secretes numerous factors (adipokines) known to markedly influence lipid and glucose/insulin metabolism, oxidative stress, and cardiovascular integrity. Some of these adipokines have been shown to directly or indirectly affect insulin sensitivity through modulation of insulin signaling and the molecules involved in glucose and lipid metabolism. A pilot study was conducted with 80 healthy subjects who were non diabetic, non hypertensive and having no family history of hypertension, the aim was to evaluate the correlation of adiponectin and leptin levels with obesity and insulin resistance markers in healthy north Indian adult population. Serum leptin, adiponectin and insulin was estimated by sandwich ELISA method. In our study, Leptin correlated significantly with BMI (P value of 0.0000), WC (P value = 0.007), and HC (P value = 0.000). leptin showed significant positive correlation with fasting insulin (P value 0.002), post prandial insulin (P value = 0.000) and HOMA-IR (P value = 0.002). Adiponectin showed significant positive correlation with triglycerides (P value = 0.038), strong negative correlation with HDL-cholesterol (P value = 0.017). Serum concentrations of leptin are associated with central body fat distribution. Insulin resistance and adiponectin is associated with dyslipidemia and these all disorders may ultimately lead to metabolic syndrome.

High-fat diet and glucocorticoid treatment cause hyperglycemia associated with adiponectin receptor alterations

BACKGROUND

Adiponectin is the most abundant plasma protein synthesized for the most part in adipose tissue, and it is an insulin-sensitive hormone, playing a central role in glucose and lipid metabolism. In addition, it increases fatty acid oxidation in the muscle and potentiates insulin inhibition of hepatic gluconeogenesis. Two adiponectin receptors have been identified: AdipoR1 is the major receptor expressed in skeletal muscle, whereas AdipoR2 is mainly expressed in liver. Consumption of high levels of dietary fat is thought to be a major factor in the promotion of obesity and insulin resistance. Excessive levels of cortisol are characterized by the symptoms of abdominal obesity, hypertension, glucose intolerance or diabetes and dyslipidemia; of note, all of these features are shared by the condition of insulin resistance. Although it has been shown that glucocorticoids inhibit adiponectin expression in vitro and in vivo, little is known about the regulation of adiponectin receptors. The link between glucocorticoids and insulin resistance may involve the adiponectin receptors and adrenalectomy might play a role not only in regulate expression and secretion of adiponectin, as well regulate the respective receptors in several tissues.

RESULTS

Feeding of a high-fat diet increased serum glucose levels and decreased adiponectin and adipoR2 mRNA expression in subcutaneous and retroperitoneal adipose tissues, respectively. Moreover, it increased both adipoR1 and adipoR2 mRNA levels in muscle and adipoR2 protein levels in liver. Adrenalectomy combined with the synthetic glucocorticoid dexamethasone treatment resulted in increased glucose and insulin levels, decreased serum adiponectin levels, reduced adiponectin mRNA in epididymal adipose tissue, reduction of adipoR2 mRNA by 7-fold in muscle and reduced adipoR1 and adipoR2 protein levels in muscle. Adrenalectomy alone increased adiponectin mRNA expression 3-fold in subcutaneous adipose tissue and reduced adipoR2 mRNA expression 2-fold in liver.

CONCLUSION

Hyperglycemia as a result of a high-fat diet is associated with an increase in the expression of the adiponectin receptors in muscle. An excess of glucocorticoids, rather than their absence, increase glucose and insulin and decrease adiponectin levels.

Increased insulin resistance and serum resistin in Korean patients with Behçet's disease

BACKGROUND AND AIMS

This study was designed to identify susceptibility to insulin resistance and the association of serum resistin and adiponectin with insulin resistance in patients with Behçet's disease (BD). Also, we identify risk determinants for insulin resistance in BD patients.

METHODS

The study population consisted of 82 BD patients (n = 26 males) and 89 healthy controls (n = 40 males). Clinical data were collected at the time of enrollment, and serum resistin and adiponectin levels were measured using enzyme-linked immunosorbent assays. The homeostasis model assessment of insulin resistance (HOMA-IR) was calculated by measuring fasting plasma glucose and insulin levels.

RESULTS

BD patients and healthy controls differed significantly in insulin resistance (HOMA-IR) (1.3 +/- 1.1 vs. 0.7 +/- 0.5, p<0.001) and serum resistin level (7901.7 +/- 1314.9 vs. 7444.2 +/- 1841.6, p = 0.001) but not in serum adiponectin level (p = 0.223). No differences in HOMA-IR, serum adiponectin, and serum resistin were found between patients with active and inactive BD. It is determined that plasma glucose, plasma insulin, and serum resistin may be determinant for the HOMA-IR. The number of metabolic syndrome components is closely correlated with HOMA-IR in BD patients (r = 0.245, p = 0.029).

CONCLUSION

This study demonstrates that there is an increased susceptibility to insulin resistance in patients with BD as compared to healthy controls. Serum resistin level may be an independent determinant for insulin resistance in BD patients.

Downregulation of ADIPOQ and PPARγ2 gene expression in subcutaneous adipose tissue of obese adolescents with hepatic steatosis

Hepatic steatosis is associated with hypoadiponectinemia. The mechanism(s) resulting in lower serum adiponectin levels in obese adolescents with fatty liver is unknown. In two groups of equally obese adolescents, but discordant for hepatic fat content, we measured adiponectin, leptin, peroxisome proliferator-activated receptor γ 2 (PPARγ2) and tumor necrosis factor-α (TNFα) gene expression in the abdominal subcutaneous adipose tissue (SAT). Twenty six adolescents with similar degrees of obesity underwent a subcutaneous periumbilical adipose tissue biopsy, in addition to metabolic (oral glucose tolerance test, and hyperinsulinemic--euglycemic clamp), and imaging studies (magnetic resonance imaging (MRI), DEXA). Using quantitative real-time-PCR; adiponectin, PPARγ2, TNFα, and leptin mRNA were measured. Based on a hepatic fat content (hepatic fat fraction, HFF) >5.5%, measured by fast MRI, the subjects were divided into low and high HFF group. In addition to the hypoadiponectinemia in the high HFF group, we found that the expression of adiponectin as well as PPARγ2 in the SAT was significantly decreased in this group. No differences were noted for TNFα and leptin plasma or mRNA levels between the groups. An inverse relationship was observed between adiponectin or PPARγ2 expression and hepatic fat content, whereas, adiponectin expression was positively related to PPARγ2 expression. Independent of overall obesity, a reduced expression of adiponectin and PPARγ2 in the abdominal SAT is associated with high liver fat content, as well as with insulin resistance in obese adolescents.

Apolipoprotein B/A-I ratio related to visceral but not to subcutaneous adipose tissue in elderly Swedes

OBJECTIVE

To investigate whether the amount of visceral (VAT) or subcutaneous adipose tissue (SAT) independently of the other can determine the apolipoprotein (apo)B/A-I ratio.

METHODS

VAT and SAT areas were assessed using magnetic resonance imaging in 247 randomly selected 70-year-old men and women who did not use lipid-lowering drugs. Their adipose tissue areas were compared to their apoB and apo A-I levels and to their apoB/A-I ratios.

RESULTS

The VAT area and the gender were significantly related to the apoB/A-I ratio whereas the SAT area was not. There was a positive relationship between the VAT area and the apoB/A-I ratio.

CONCLUSION

A positive relationship was established between the amount of VAT and the apoB/A-I ratio, whereas there was no relationship between the amount of SAT and the apoB/A-I ratio. This observation supports the notion that VAT is metabolically active.

Involvement of adipokines in rimonabant-mediated insulin sensitivity in ob/ob mice

Objectives

It has been recently reported that blockade of type 1 cannabinoid (CB1) receptors by specific antagonists or genetic manipulation alleviates dyslipidaemia, hyperglycaemia and insulin resistance in animal models of obesity and type 2 diabetes. However, the precise role of adipokines in the insulin-sensitising effects of the CB1 antagonist rimonabant is not clear.

Methods

ob/ob mice were treated with different doses of rimonabant and then subjected to an oral glucose tolerance test. The expression of different adipokines in white adipose tissue was analysed by quantitative real-time PCR.

Key findings

Rimonabant (30 mg/kg) significantly inhibited body weight and fat pad weight gain (P &lt; 0.05) and improved glucose tolerance. Gene expression analysis indicated that tumour necrosis factor-α, visfatin and retinol binding protein-4 were downregulated in the adipose tissue of ob/ob mice treated with rimonabant compared with controls, whereas adiponectin was significantly upregulated.

Conclusions

Rimonabant-mediated alteration of adipokines in white adipose tissues may play a role in improving insulin sensitivity in obese animals.

Impact of type 1 diabetes and insulin treatment on plasma levels and fractional synthesis rate of retinol-binding protein 4

CONTEXT

Retinol binding protein 4 (RBP4) levels are elevated in insulin-resistant states and reduced in type 1 diabetes (T1D), but it is unknown whether changes in insulin levels and glycemic control alter RBP4 levels. In vivo synthesis rates of RBP4 and their relationship to RBP4 levels remain to be determined.

OBJECTIVE

The aim of the study was to determine whether the synthesis rate of RBP4 is altered in people with T1D during both insulin deficiency and insulin treatment.

DESIGN

Seven T1D participants were studied on two occasions, during 8 h of insulin deprivation and during insulin treatment, and compared with nondiabetic (ND) controls.

MAIN OUTCOME MEASURES

We measured in vivo fractional synthesis rate of RBP4 using [ring-(13)C(6)]phenylalanine as a tracer and RBP4 concentration in plasma by nephelometric assay and Western blot analyses.

RESULTS

Plasma RBP4 levels were lower (P < 0.01) in insulin-treated T1D than in ND but were not different between insulin-deprived T1D and ND participants. Synthesis rates of RBP4 in ND (2.46 +/- 0.29%/h) were higher than in insulin-treated T1D (1.45 +/- 0.21) (P = 0.02), but there was no difference between ND and insulin-deprived T1D (2.24 +/- 0.24). Glucose levels were not different between ND and insulin-treated T1D, but insulin levels were higher in insulin-treated T1D (82.8 +/- 2 pmol/liter) than in ND (28.7 +/- 6) and insulin-deprived T1D (4.6 +/- 1.6) (P < 0.01).

CONCLUSIONS

Insulin treatment that achieved normoglycemia but relative hyperinsulinemia was associated with lower RBP4 synthesis and levels in T1D. Short-term insulin deprivation and hyperglycemia had no effect on RBP4 levels and synthesis rates in T1D.

Trans-10, cis-12-conjugated linoleic acid reduces the hepatic triacylglycerol content and the leptin mRNA level in adipose tissue in obese Zucker fa/fa rats

Conjugated linoleic acid (CLA) isomers have been reported to reduce body weight and beneficially affect glucose metabolism in animals, but the results are inconsistent and seem to depend on animal model and type of CLA isomer. In the present study, feeding male Zucker fa/fa rats diets supplemented with 1% trans-10, cis-12-CLA for 10 d reduced the liver TAG content without improving the overall adiposity, and enhanced hepatic mitochondrial and peroxisomal beta-oxidation. The increased carnitine palmitoyltransferase (CPT)-I activity and mRNA level as well as the increased n-3:n-6 PUFA ratio in liver suggest that trans-10, cis-12-CLA increased the hepatic beta-oxidation by stimulation of PPARalpha. The reduced hepatic TAG content may be partly due to lower activity of stearoyl-CoA desaturase, as the ratios of 18 : 1n-9:18 : 0 and 16 : 1n-7:16 : 0 were reduced in liver. Trans-10, cis-12-CLA increased the CPT-I mRNA in retroperitoneal white adipose tissue (WAT), and increased uncoupling protein-2 mRNA in epididymal and inguinal WAT depots. Leptin mRNA level was decreased in all examined WAT depots, implying reduced insulin sensitivity. The resistin mRNA level was increased in all WAT depots, whereas adiponectin mRNA was reduced in inguinal and retroperitoneal WAT. The present results suggest that dietary supplementation with trans-10, cis-12-CLA may increase the catabolism of lipids in liver and adipose tissue. Moreover, we provide new data suggesting that trans-10, cis-12-CLA modulates the expression of resistin and adiponectin inversely in adipose tissue. Hence, the present results suggest that trans-10, cis-12-CLA may have some beneficial effects on lipid metabolism and adiposity but possibly reduces insulin sensitivity.

Relationship between adiponectin and non-alcoholic fatty liver disease in Uygur national minority

AIM: To investigate the relation of adiponectin with non-alcoholic fatty liver disease (NAFLD) in Uygur national minority.

METHODS: Two hundred and sixty patients with non-alcoholic fatty liver disease (NAFLD) served as fatty liver disease group, while 129 healthy people served as normal control group who were all Uygur nationality. Blood pressure, height, physique were measured and 2-hour intravenous blood of empty stomach and OGTT were collected to measure blood fat, insulin, blood glucose and adiponectin level. BMI and HOMA-IR were assessed. Relationship of lipoprotein with NAFLD and with index described above were analyzed and investigated.

RESULTS: After correcting such confounding factors as sex, age, BMI, SBP, DBP, TC, HDL, LDL, TG, FBG, PBG, FINS, PINS, serum adiponectin level was significantly reduced in fatty liver group compared with normal group. And the incidence rate, BMI, SBP, DBP, TC, HDL, LDL, TG, FBG, PBG, FINS, HOMA-IR level decreased as serum lipoprotein increased (P < 0.05). Logistic return analysis showed that after consideration of confounding factors such as sex, age, BMI, SBP, DBP, HOMA-IR, TC, HDL, LDL, TG, FBG, PBG, FINS, PINS, the OR values for second, third and four layer were 0.460 (P = 0.031), 0.449 (P = 0.022), 0.099 (P = 0.000) respectively compared with the first layer

CONCLUSION: NAFLD adiponectin level is lower in Uygur nationality, and is also an independent risk factor.

Serum adiponectin during pregnancy and postpartum in women with gestational diabetes and normal controls

AIMS

To investigate changes in serum adiponectin during pregnancy and postpartum and assess its relationship with insulin resistance as measured by homeostasis model assessment (HOMA-IR).

METHODS

Twenty-two normal pregnant women were compared with 22 women diagnosed with gestational diabetes mellitus (GDM). Serum adiponectin levels were measured at the time of the glucose challenge test as well as in the immediate postpartum period and the correlation of adiponectin to HOMA-IR was performed.

RESULTS

Adiponectin was significantly lower in women with GDM than in controls during pregnancy (5381 vs. 8449 ng/dl, p = 0.004), as well as postpartum (3278 vs. 6958 ng/ml, p = 0.002). A significant reduction in adiponectin (3278 vs. 5381 ng/ml, p = 0.002) was observed postpartum in GDM women but not in controls. Using a lower cut-off value of 5253 ng/ml, maternal adiponectin could exclude GDM with a sensitivity of 86.4% and a specificity of 59.1% (area under the curve = 0.752, standard error = 0.77, 95% confidence interval 0.601-0.903, p = 0.004). Adiponectin levels during pregnancy were negatively correlated with HOMA-IR (r = -0.375, p = 0.012).

CONCLUSION

GDM is associated with decreased serum adiponectin levels both in pregnancy as well as postpartum. Adiponectin is negatively correlated to HOMA-IR. A reduction in maternal adiponectin after delivery indicates a significant placental contribution to adiponectin production.