Decreased plasma adiponectin is associated with insulin resistance and HDL cholesterol in overweight subjects

Exerkines: Benign adaptation for exercise and benefits for non-alcoholic fatty liver disease

Exercise has multiple beneficial effects on human metabolic health and is regarded as a "polypill" for various diseases. At present, the lack of physical activity usually causes an epidemic of chronic metabolic syndromes, including obesity, cardiovascular diseases, and non-alcoholic fatty liver disease (NAFLD). Remarkably, NAFLD is emerging as a serious public health issue and is associated with the development of cirrhosis and hepatocellular carcinoma. Unfortunately, specific drug therapies for NAFLD and its more severe form, non-alcoholic steatohepatitis (NASH), are currently unavailable. Lifestyle modification is the foundation of treatment recommendations for NAFLD and NASH, especially for exercise. There are under-appreciated organs that crosstalk to the liver during exercise such as muscle-liver crosstalk. Previous studies have reported that certain exerkines, such as FGF21, GDF15, irisin, and adiponectin, are beneficial for liver metabolism and have the potential to be targeted for NAFLD treatment. In addition, some of exerkines can be modified for the new proteins and get enhanced functions, like IL-6/IC7Fc. Another importance of exercise is the physiological adaptation that combats metabolic diseases. Thus, this review aims to summarize the known exerkines and utilize a multi-omics mining tool to identify more exerkines for the future research. Overall, understanding the mechanisms by which exercise-induced exerkines exert their beneficial effects on metabolic health holds promise for the development of novel therapeutic strategies for NAFLD and related diseases.

Association between Inflammatory Factors, Vitamin D, Long Non-Coding RNAs, MALAT1, and Adiponectin Antisense in Individuals with Metabolic Syndrome

BACKGROUND

Metabolic syndrome (MetS) is a common clustering of cardiovascular risk factors associated with increased inflammation. Long non-coding RNA (LncRNA) are involved in many of the body's metabolic activities, including inflammation. Vitamin D may play a vital role in preventing metabolic syndrome risk factors. This study aimed to evaluate the status of inflammation and expression of LncRNA and their relationship with serum vitamin D levels in patients with metabolic syndrome.

METHOD

This cross-sectional study included staff and Mashhad University of Medical Sciences students between 30 and 50 years old who met the International Diabetes Federation criteria for Mets. Total RNA was extracted from both frozen clinical samples using the Trizol reagent.

RESULTS

A total of eighty people were recruited into the two groups, with and without MetS. Inflammatory markers were higher in the individuals in the MetS group, and linear regression showed an inverse association between serum vitamin D and LncRNAs. There was a positive association between inflammatory biomarkers, lipid profiles and Adiponectin Antisense (APQ AS) expression.

CONCLUSION

APQ AS and MALAT1 levels are positively associated with inflammatory biomarkers and inverse relation between MALAT1 and serum 25 (OH) D concentration.

Effect of Different Intensities of Aerobic Exercise Combined with Resistance Exercise on Body Fat, Lipid Profiles, and Adipokines in Middle-Aged Women with Obesity

We aimed to investigate the effect of different intensities of aerobic exercise (VO₂max: 50% vs. 80%) on body weight, body fat percentage, lipid profiles, and adipokines in obese middle-aged women after 8 weeks of combined aerobic and resistance exercise. The participants included 16 women aged >40 years with a body fat percentage of ≥30%; they were randomly assigned to the resistance and either moderate (RME, 50% VO₂max, 200 kcal [n = 8]) or vigorous aerobic exercise groups (RVE, 80% VO₂max, 200 kcal [n = 8]), respectively. After 8 weeks of exercise, we observed that body weight and body fat percentage decreased significantly in both groups (p < 0.01). The total cholesterol (p < 0.01) and LDL (p < 0.05) levels decreased significantly in the RME group, while triglyceride levels decreased significantly in both groups (p < 0.01). The HDL levels tended to increase only slightly in both groups. The adiponectin levels decreased significantly in the RVE group (p < 0.05), and the leptin levels decreased significantly in both groups (p < 0.05). To prevent and treat obesity in middle-aged women, combined exercise (aerobic and resistance) is deemed effective; additionally, aerobic exercise of moderate intensity during combined exercise could be more effective than that of vigorous intensity.

Associations of a Panel of Adipokines with Fat Deposits and Metabolic Phenotypes in a General Population

OBJECTIVE

This study provides a comprehensive overview of the associations of five adipokines (adiponectin, chemerin, galectin-3, leptin, and resistin) with fat deposits, behavioral risk factors, and metabolic phenotypes.

METHODS

Using multivariable linear and logistic regression models, cross-sectional data from 4,116 participants of the population-based Study of Health in Pomerania were analyzed.

RESULTS

Participants with obesity showed higher chemerin, galectin-3, and leptin but showed lower adiponectin concentrations. Independently of other fat compounds, liver fat content, visceral adipose tissue, and subcutaneous adipose tissue (SAT) were inversely associated with adiponectin. Independent positive associations of liver fat content and SAT with chemerin as well as of SAT with galectin-3 and leptin were observed. Physically inactive participants had higher chemerin and leptin concentrations. Smokers had higher chemerin and galectin-3 as well as lower leptin. Alcohol consumption was associated with adiponectin (positive) and resistin (inverse). All adipokines were associated with at least one lipid marker. Associations with glucose metabolism were seen for adiponectin, chemerin, galectin-3, and leptin.

CONCLUSIONS

High adiponectin concentrations were related to favorable metabolic conditions, whereas high chemerin, galectin-3, and leptin were associated with an unfavorable metabolic profile. High leptin seems to be primarily indicative of obesity, whereas high adiponectin and chemerin are associated with a broader range of metabolic phenotypes.

Adiponectin and its receptor genes' expression in response to Marek's disease virus infection of White Leghorns

Marek’s disease virus (MDV) causes T-cell lymphoma in susceptible chicken and is also related to an imbalance of the lipid metabolism. Adiponectin is a circulatory cytokine secreted from adipose tissue and exerts critical metabolic functions. Although the associations between adiponectin and diseases, including lipid disorder and noncardiac vascular diseases, have been reported, little is known about the relationship between MDV infection and adiponectin. Here, we challenged white Leghorns from Marek’s disease (MD)-susceptible and MD-resistant lines with MDV at 7 D of age and then explored the body weight and plasma lipoprotein levels at 21 D after MDV infection. Meanwhile, adiponectin and the expression of its receptors were detected using quantitative real-time PCR and Western blot. The results showed that MDV infection induced body weight loss in all the experimental birds. Meanwhile, the concentrations of total cholesterol and high-density lipoprotein were lower after the infection, although there was no significant difference (P > 0.05). However, the infection did not affect adiponectin circulating levels in plasma. MD-susceptible birds had much lower plasma adiponectin than MD-resistant birds (P < 0.01). In abdominal fat, there was no significant difference in adiponectin mRNA level. Still, we observed a significant decrease in adiponectin protein concentration, as well as adipoR1 and adipoR2, at both mRNA and protein levels in the infected compared with the noninfected MD-susceptible chickens. In the spleen, MDV infection significantly reduced the adiponectin mRNA expression but increased the protein in MD-susceptible chickens, which decreased both adipoR1 mRNA expression and protein levels. Also interestingly, the adipoR1 mRNA expression level was significantly increased in MD-susceptible chickens in the liver after MDV infection. All findings in the present study provided interesting insights into adiponectin metabolism in chickens after MDV infection, which helps to advance the understanding of lipid metabolism in response to herpesvirus infection.

Serum Anti-Müllerian Hormone in Polycystic Ovary Syndrome and its Relationship with Insulin Resistance, Lipid Profile and Adiponectin

OBJECTIVES

This study was done to estimate serum anti-Müllerian hormone (AMH) level in polycystic ovary syndrome (PCOS) patients and to correlate serum AMH level with insulin resistance, lipid profile, and adiponectin levels.

MATERIALS AND METHODS

A cross-sectional study was conducted at Hospital Universiti Sains Malaysia (Hospital USM), Health Campus, Kubang Kerian, Kelantan, Malaysia. Thirty newly diagnosed patients with PCOS attending gynecology clinic between July 2016 and April 2017 were recruited. Fasting venous blood samples were collected from the subjects. Serum AMH, insulin, adiponectin, triglycerides, high-density lipoprotein cholesterol (HDL-C), and plasma glucose levels were measured, and insulin resistance was calculated based on homeostasis model of assessment-insulin resistance (HOMA-IR). The serum AMH level was estimated, and the correlation of serum AMH level with the metabolic parameters was analyzed.

RESULTS

The median of serum AMH levels in women with PCOS was 6.8 ng/mL (interquartile range: 7.38 ng/mL). There was a significant negative correlation between serum AMH and HOMA-IR or triglyceride levels (r = -0.49, P = 0.006 and r = -0.55, P = 0.002, respectively). A significant positive correlation was observed between serum AMH and serum HDL-C or serum adiponectin levels (r = 0.56, P = 0.001 and r = 0.44, P = 0.014, respectively) in all study subjects.

CONCLUSION

The serum AMH level is associated with HOMA-IR, triglycerides, HDL-C, and adiponectin levels, and hence it may be used as a potential cardiometabolic risk marker in women with PCOS.

The Clinical Utility of Salivary Biomarkers in the Identification of Type 2 Diabetes Risk and Metabolic Syndrome

Type 2 diabetes is traditionally diagnosed by the use of an oral glucose tolerance test and/or HbA1c, both of which require serum collection. Various biomarkers, which are measurable biological substances that provide clinical insight on disease state, have also been effective in the early identification and risk prediction of inflammatory diseases. Measuring biomarker concentrations has traditionally been obtained through serum collection as well. However, numerous biomarkers are detectable in saliva. Salivary analysis has more recently been introduced into research as a potential non-invasive, cost-effective diagnostic for the early identification of type 2 diabetes risk in adults and youth. Therefore, the purpose of this review was to compare 6 established inflammatory biomarkers of type 2 diabetes, in serum and saliva, and determine if similar diagnostic effectiveness is seen in saliva. A lack of standardized salivary analysis, processing, and collection accounts for errors and inconsistencies in conclusive data amongst studies. Proposing a national standardization in salivary analysis, coupled with increased data and research on the utility of saliva as a diagnostic, poses the potential for salivary analysis to be used in diagnostic settings.

Expression of apolipoprotein M and its association with adiponectin in an obese mouse model

The aim of the present study was to explore the association between apolipoprotein M (ApoM) and adiponectin, and the underlying mechanism, via observation of ApoM expression in an obese mouse model. For in vivo experiments, mice were randomly distributed into four groups: Control group, obese group, obese group treated with adiponectin, and normal group treated with adiponectin. Body weight, plasma adiponectin, blood glucose and fasting insulin were measured and visceral adipose tissue was weighed at the end of the experiment. ApoM and transcription factor forkhead box A2 (Foxa2) mRNA expression in the mouse liver was evaluated and the protein level of ApoM detected. For in vitro experiments, an insulin-resistant (IR) hepatic cell model was established by inducing the HepG2 cell line with a high concentration of insulin. Following treatment with adiponectin, changes in ApoM and Foxa2 mRNA expression and ApoM protein expression were evaluated in the control and IR HepG2 cells. Results demonstrated that compared with the control group, body weight, visceral adipose tissue weight, blood glucose, fasting insulin and insulin-resistance index (HOMA-IR) were significantly increased in the obese group, whilst plasma adiponectin, ApoM mRNA expression, Foxa2 mRNA expression and ApoM protein in the mouse liver were all significantly decreased. Following intervention with adiponectin in obese mice, blood glucose, insulin and HOMA-IR were significantly decreased, whilst plasma adiponectin, ApoM mRNA expression, Foxa2 mRNA expression and ApoM protein were all significantly increased. However, no significant difference was observed in visceral adipose tissue weight following the intervention of adiponectin in obese mice. In vitro, in the absence of intervention, ApoM and Foxa2 mRNA expression and ApoM protein expression were significantly lower in IR HepG2 cells compared with HepG2 cells. Following intervention with adiponectin on IR HepG2 cells, ApoM and Foxa2 mRNA expression and ApoM protein expression were significantly increased. However, the intervention did not have any effect on HepG2 cells. In conclusion, intervention with adiponectin elevated ApoM mRNA expression, potentially via relieving IR and upregulating Foxa2 mRNA expression.

Total adiponectin in overweight and obese subjects and its response to visceral fat loss

BACKGROUND

Visceral obesity and related diabetes is reaching epidemic proportions in the United Arab Emirates (UAE). Adiponectin is a hormone that is secreted by adipose tissue and may play an important role in obesity-related morbidity. The aim of this study was to investigate total adiponectin levels in overweight and obese UAE subjects visiting health care facilities for weight management.

METHODS

All overweight and obese subjects visiting community health centers were invited to take part in the study. Two hundred and six participants received individualized structured dietary education for weight management. Demographic data, anthropometric measurements and fasting venous blood samples were taken for measurements of total adiponectin and markers of inflammation and nutritional status at baseline and follow up. Multivariate analysis was performed to determine the independent effects of prognostic factors on serum adiponectin levels.

RESULTS

A total of 193 (93%) females with a mean age (±SD) 36 ± 11 years were included in the analysis. During a follow up period of 427 ± 223 days, participants received 13 ± 5 structured dietary education sessions. We observed decreased levels of total adiponectin with increasing quartiles of both waist circumference (WC) and body mass index (BMI). Male gender and history of both gestational and type 2 diabetes were associated with significantly lower total adiponectin levels (p < 0.05). After adjusting for age, gender, BMI and hip circumference, multiple regression analysis revealed a significant and independent association between waist circumference and total adiponectin levels. At follow up visceral fat loss was associated with a significant decrease in inflammatory markers and a non-significant increase in total adiponectin levels.

CONCLUSION

Increased visceral fat in overweight and obese subjects is associated with decreased total adiponectin levels. The health benefits of increasing adiponectin levels using different dietary intervention strategies need to be explored in larger studies.

TRIAL REGISTRATION

NCT01691365 , registered on 11/09/2012.

Long-lived hypopituitary Ames dwarf mice are resistant to the detrimental effects of high-fat diet on metabolic function and energy expenditure

Growth hormone (GH) signaling stimulates the production of IGF‐1; however, increased GH signaling may induce insulin resistance and can reduce life expectancy in both mice and humans. Interestingly, disruption of GH signaling by reducing plasma GH levels significantly improves health span and extends lifespan in mice, as observed in Ames dwarf mice. In addition, these mice have increased adiposity, yet are more insulin sensitive compared to control mice. Metabolic stressors such as high‐fat diet (HFD) promote obesity and may alter longevity through the GH signaling pathway. Therefore, our objective was to investigate the effects of a HFD (metabolic stressor) on genetic mechanisms that regulate metabolism during aging. We show that Ames dwarf mice fed HFD for 12 weeks had an increase in subcutaneous and visceral adiposity as a result of diet‐induced obesity, yet are more insulin sensitive and have higher levels of adiponectin compared to control mice fed HFD. Furthermore, energy expenditure was higher in Ames dwarf mice fed HFD than in control mice fed HFD. Additionally, we show that transplant of epididymal white adipose tissue (eWAT) from Ames dwarf mice fed HFD into control mice fed HFD improves their insulin sensitivity. We conclude that Ames dwarf mice are resistant to the detrimental metabolic effects of HFD and that visceral adipose tissue of Ames dwarf mice improves insulin sensitivity in control mice fed HFD.

Are decreased AdipoR1 mRNA levels associated with adiponectin resistance in coronary artery disease patients?

The aim of the present study was to investigate if circulating adiponectin levels and the expression of AdipoR1 and AdipoR2 in peripheral blood mononuclear cells (PBMC) are altered in coronary artery disease (CAD) patients, with and without significant stenosis, compared to healthy patients. The present study included 69 patients with presenting symptoms of CAD (26 patients with significant stenosis and 43 patients without significant stenosis). The control group (CG) consisted of 33 healthy patients. Circulating adiponectin levels were measured by enzyme-linked immunosorbent assay, whereas AdipoR1 and AdipoR2 mRNA levels in PBMC were determined by real-time polymerase chain reaction. Adiponectin levels were significantly higher in patients with and without significant stenosis compared to the CG (P < 0.001 vs P = 0.006, respectively). Both patient groups had lower AdipoR1 levels compared to the CG (P < 0.001 vs P < 0.001, respectively). There were no significant differences in these parameters between the two patient groups. Adiponectin negatively correlated with body mass index, triglycerides, insulin and homeostasis model assessment of insulin resistance index (HOMA IR), and positively with high-denisty lipoprotein cholesterol in the CG. Glucose, insulin, and the HOMA IR index negatively correlated with adiponectin in patients. A positive correlation between adiponectin receptors was found in patients and the CG. Decreased AdipoR1 mRNA levels and increased circulating adiponectin in advanced stages of CAD, as well as in patients without significant stenosis, compared to the CG, implies that CAD could be related to 'adiponectin resistance'. Despite increased adiponectin, its protective effects could be diminished even in early stages of atherosclerosis.

Serum Adiponectin Levels and Changes in Glucose Metabolism before and after Treatment for Thyroid Dysfunction

OBJECTIVE

Adiponectin is an adipokine which is known to decrease in individuals associated with obesity and insulin resistance. In this study, we aimed to investigate the serum adiponectin levels and glucose metabolism in patients with thyroid dysfunction before and after treatment.

METHODS

Newly diagnosed overt hypothyroid (n=20) and thyrotoxic (n=23) patients and healthy controls (n=20) with a body mass index of <30 kg/m(2) were evaluated prospectively. Patients with a known state of insulin resistance, including prediabetes and overt diabetes, and individuals with chronic diseases were excluded. Thyroid function and fasting plasma glucose (FPG), insulin, homeostatic model assessment (HOMA) insulin resistance (HOMA-IR) and HOMA-beta cell function (HOMA-beta), lipid and adiponectin levels were investigated in the basal state and after the restoration of euthyroidism.

RESULTS

The basal fasting FPG levels were lower in the hypothyroid patients than the control subjects (p=0.02) and similar between the thyrotoxic patients and control subjects (p=0.127). The basal HOMA-beta levels were higher in the patients with hypothyroidism than in those with thyrotoxicosis (p=0.015). Following the restoration of euthyroidism, the FPG levels significantly increased in the hypothyroid patients (p=0.002) and decreased in the thyrotoxic (p=0.001) patients. The basal plasma adiponectin levels were 14.55±8.4 mcg/mL, 13.79±9.13 mcg/mL and 11.68±6.0 mcg/mL in the hypothyroid and thyrotoxic patients and healthy controls, respectively (p=0.503). The adiponectin levels decreased significantly in the patients with hypothyroidism (p=0.047), whereas they did not change in the patients with thyrotoxicosis (p=0.770) after achieving euthyroidism.

CONCLUSION

In this study, following the restoration of euthyroidism, the FPG levels increased in the hypothyroidism patients and decreased in the thyrotoxicosis patients, despite the lack of changes in the HOMA-IR and HOMA-beta levels. Meanwhile, the hypothyroid, thyrotoxic and euthyroid subjects had similar basal adiponectin levels, and a significant decrease in the adiponectin levels was observed after treatment for hypothyroidism, despite the absence of changes after treatment for thyrotoxicosis, indicating the need for further studies with a larger sample size.

Biomarker patterns of inflammatory and metabolic pathways are associated with risk of colorectal cancer: results from the European Prospective Investigation into Cancer and Nutrition (EPIC)

A number of biomarkers of inflammatory and metabolic pathways are individually related to higher risk of colorectal cancer (CRC); however, the association between biomarker patterns and CRC incidence has not been previously evaluated. Our study investigates the association of biomarker patterns with CRC in a prospective nested case-control study within the European Prospective Investigation into Cancer and Nutrition (EPIC). During median follow-up time of 7.0 (3.7-9.4) years, 1,260 incident CRC cases occurred and were matched to 1,260 controls using risk-set sampling. Pre-diagnostic measurements of C-peptide, glycated hemoglobin, triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), C-reactive protein (CRP), reactive oxygen metabolites (ROM), insulin-like growth factor 1, adiponectin, leptin and soluble leptin receptor (sOB-R) were used to derive biomarker patterns from principal component analysis (PCA). The relation with CRC incidence was assessed using conditional logistic regression models. We identified four biomarker patterns 'HDL-C/Adiponectin fractions', 'ROM/CRP', 'TG/C-peptide' and 'leptin/sOB-R' to explain 60 % of the overall biomarker variance. In multivariable-adjusted logistic regression, the 'HDL-C/Adiponectin fractions', 'ROM/CRP' and 'leptin/sOB-R' patterns were associated with CRC risk [for the highest quartile vs the lowest, incidence rate ratio (IRR) = 0.69, 95 % CI 0.51-0.93, P-trend = 0.01; IRR = 1.70, 95 % CI 1.30-2.23, P-trend = 0.002; and IRR = 0.79, 95 % CI 0.58-1.07; P-trend = 0.05, respectively]. In contrast, the 'TG/C-peptide' pattern was not associated with CRC risk (IRR = 0.75, 95 % CI 0.56-1.00, P-trend = 0.24). After cases within the first 2 follow-up years were excluded, the 'ROM/CRP' pattern was no longer associated with CRC risk, suggesting potential influence of preclinical disease on these associations. By application of PCA, the study identified 'HDL-C/Adiponectin fractions', 'ROM/CRP' and 'leptin/sOB-R' as biomarker patterns representing potentially important pathways for CRC development.

Role of adiponectin in the metabolic effects of cannabinoid type 1 receptor blockade in mice with diet-induced obesity

The adipocyte-derived hormone adiponectin promotes fatty acid oxidation and improves insulin sensitivity and thus plays a key role in the regulation of lipid and glucose metabolism and energy homeostasis. Chronic cannabinoid type 1 (CB1) receptor blockade also increases lipid oxidation and improves insulin sensitivity in obese individuals or animals, resulting in reduced cardiometabolic risk. Chronic CB1 blockade reverses the obesity-related decline in serum adiponectin levels, which has been proposed to account for the metabolic effects of CB1 antagonists. Here, we investigated the metabolic actions of the CB1 inverse agonist rimonabant in high-fat diet (HFD)-induced obese adiponectin knockout (Adipo(-/-)) mice and their wild-type littermate controls (Adipo(+/+)). HFD-induced obesity and its hormonal/metabolic consequences were indistinguishable in the two strains. Daily treatment of obese mice with rimonabant for 7 days resulted in significant and comparable reductions in body weight, serum leptin, free fatty acid, cholesterol, and triglyceride levels in the two strains. Rimonabant treatment improved glucose homeostasis and insulin sensitivity to the same extent in Adipo(+/+) and Adipo(-/-) mice, whereas it reversed the HFD-induced hepatic steatosis, fibrosis, and hepatocellular damage only in the former. The adiponectin-dependent, antisteatotic effect of rimonabant was mediated by reduced uptake and increased β-oxidation of fatty acids in the liver. We conclude that reversal of the HFD-induced hepatic steatosis and fibrosis by chronic CB1 blockade, but not the parallel reduction in adiposity and improved glycemic control, is mediated by adiponectin.

Decreased submandibular adiponectin is involved in the progression of autoimmune sialoadenitis in non-obese diabetic mice

OBJECTIVE

To investigate a possible role of adiponectin in the pathogenesis of autoimmune sialoadenitis in non-obese diabetic (NOD) mouse model of Sjögren's syndrome.

MATERIALS AND METHODS

Expression of adiponectin and its receptors (AdipoR1/2) was detected by PCR, immunoblotting, or immunofluorescence. The level of adiponectin was quantified by ELISA. Adiponectin-related signaling molecules and pro-inflammatory cytokines were examined by PCR or immunoblotting. Apoptosis was evaluated by TUNEL staining, flow cytometry, and caspase 3 activation.

RESULTS

Adiponectin and AdipoR1/2 mRNA and protein were expressed in submandibular glands. Adiponectin immunostaining was widely diffused in the cytoplasm of acinar and ductal cells. AdipoR1 was mainly distributed in acinar cytoplasm, while AdipoR2 was predominantly located at acinar cell membrane. Submandibular adiponectin levels were reduced during the progression of autoimmune sialoadenitis in 7-, 14-, and 21-week-old NOD mice, while AdipoR1/2 levels were unchanged. The levels of phosphorylated adenosine monophosphate-activated protein kinase, extracellular signal-regulated kinase 1/2, and p38 mitogen-activated protein kinase were decreased, while interferon (IFN)-γ and glandular apoptosis were temporally increased at all time points. Moreover, exogenous adiponectin supplement inhibited, whereas neutralizing endogenous adiponectin by its antibody promoted IFN-γ-induced apoptosis and caspase 3 activation in cultured submandibular acinar cells.

CONCLUSIONS

Adiponectin plays a protective role on submandibular cells. Decreased adiponectin might promote glandular destruction in autoimmune sialoadenitis.

Usefulness of the insulin tolerance test in patients with type 2 diabetes receiving insulin therapy

Aims/Introduction

To establish the validity of the plasma glucose disappearance rate (KITT), derived from an insulin‐tolerance test (ITT), for evaluating the insulin sensitivity of patients with type 2 diabetes after insulin therapy.

Materials and Methods

In the first arm of the study, 19 patients with poorly controlled diabetes were treated with insulin and underwent an ITT and a euglycemic clamp test (clamp‐IR). The relationship between the insulin resistance index, as assessed by both the clamp‐IR and KITT tests, was examined. In the second arm of the study, the relationships between KITT values and various clinical parameters were investigated in 135 patients with poorly controlled diabetes, after achieving glycemic control with insulin.

Results

In study 1, a close correlation between KITT and the average glucose infusion rate during the last 30 min of the standard clamp‐IR test (M‐value) was noted (P < 0.001). In study 2, body mass index (P = 0.0011), waist circumference (P = 0.0004), visceral fat area (P = 0.0011) and the log‐transformed homeostasis model assessment of insulin resistance value (P = 0.0003) were negatively correlated with the log‐transformed KITT. High‐density lipoprotein cholesterol (P = 0.0183), low‐density lipoprotein cholesterol (P = 0.0121) and adiponectin (P = 0.0384) levels were positively correlated with the log‐transformed KITT.

Conclusions

The ITT is a valid and useful test for evaluating the insulin sensitivity of patients with diabetes, even after treatment with insulin.

Hypoadiponectinemia: a useful marker of dyslipidemia in women with polycystic ovary syndrome

OBJECTIVE

Adiponectin plays a role in obesity, lipid metabolism, and anti-inflammation. Women with polycystic ovary syndrome (PCOS) are also at risk for dyslipidemia. Therefore, we investigated the association between adiponectin levels and the lipid profile including high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TGs) in women with PCOS and contemplated what role adiponectin might play in dyslipidemia with PCOS.

MATERIALS AND METHODS

We recruited 118 young Taiwanese women with PCOS. The women enrolled were not taking any medication and those with other systemic diseases of nonovarian origin, which could have affected the hypothalamic-pituitary-ovarian axis, were excluded. The serum lipid profile, metabolic and hormonal parameters, and adiponectin were measured. The lipid profile and adiponectin were analyzed and adjusted for age, body mass index (BMI), homeostasis model assessment-insulin resistance (HOMA-IR), and sex hormone-binding globulin (SHBG).

RESULTS

In a simple linear regression, adiponectin was significantly inversely related to LDL-C and TGs, but positively related to HDL-C (all p < 0.001) after logarithmic transformation. In the multiple linear regression, adiponectin was significantly related to HDL-C (p < 0.001) independent of age, BMI, HOMA-IR, and SHBG after logarithmic transformation. Using a logistic regression, the odds ratio was 0.088 between the association of increased adiponectin and abnormal HDL-C (≤ 50 mg/dL).

CONCLUSIONS

We demonstrated that adiponectin is an independent biomarker that is positively and evidently related to HDL-C and TGs in women with PCOS. Hypoadiponectinemia may be a useful marker of dyslipidemia in women with PCOS.

Homeostasis model assessment of insulin resistance for evaluating insulin sensitivity in patients with type 2 diabetes on insulin therapy

Homeostasis model assessment of insulin resistance (HOMA-IR) is a simple and useful method for evaluating insulin sensitivity. But it is difficult to apply to type2 diabetes patients treated with insulin. We have devised a method for measuring HOMA-IR and investigated the validity of HOMA-IR for evaluating insulin sensitivity in patients with type 2 diabetes on insulin therapy. In the first arm of the study, 19 poorly controlled diabetic subjects were treated with insulin and underwent euglycemic clamp study. Then the relationship between insulin resistance index assessed by the clamp test (clamp-IR) and HOMA-IR was investigated in these subjects. Log transformed HOMA-IR correlated with log transformed M/I values derived from the standard euglycemic clamp (r=-0.753, p=0.002). In the second arm of the study, we investigated the relationship between HOMA-IR and various clinical parameters in 156 patients with poorly controlled diabetes after glycemic control. Log transformed HOMA-IR correlated negatively with age (r=-0.292, p=0.0002), HDL-C (r=-0.342, p<0.0001), log transformed serum adiponectin (r=-0.309, p=0.0006) and log transformed KITT (r=-0.264, p=0.0009), and positively with body mass index (r=0.499, p<0.0001), waist circumstance (r=0.461, p<0.0001), visceral fat area (r=0.401, p<0.0001), diastolic blood pressure (r=0.223, p=0.0054), log transformed triglyceride (r=0.497, p<0.0001), urinary CPR (r=0.216, p=0.0099), ΔCPR of glucagon stimulation test (r=0.496, p<0.0001) and log transformed insulinogenic index (r=0.325, p=0.0002). These results suggest that HOMA-IR is a useful test for the evaluation of insulin sensitivity even in patients with type 2 diabetes treated with insulin.

Effect of a High Protein Weight Loss Diet on Weight, High-Sensitivity C-Reactive Protein, and Cardiovascular Risk among Overweight and Obese Women: A Parallel Clinical Trial

Studies regarding the effects of high protein (HP) diets on cardiovascular (CVD) risk factors have reported contradictory results. We aimed to determine the effects of an HP diet on CVD risk factors and high-sensitivity C-reactive protein (hs-CRP) among overweight and obese women. In this randomized controlled trial, we recruited 60 overweight and obese women, aged 20-65, into an HP or energy-restricted control diet for three months (protein, carbohydrate, and fat: 25%, 45%, and 30% versus 15%, 55%, and 30%, resp.). Total protein was divided between animal and plant sources in a 1 : 1 ratio, and animal sources were distributed equally between meats and dairy products. Fasting blood samples, hs-CRP, lipid profile, systolic and diastolic blood pressure, and anthropometric measurements were assessed using standard guidelines. Percent change was significantly different between the two diet groups for weight (standard protein (SP): -3.90 ± 0.26 versus HP: -6.10 ± 0.34%; P < 0.0001, resp.) and waist circumference (SP: -3.03 ± 0.21 versus HP: -5.06 ± 0.28%; P < 0.0001, resp.). Percent change of fasting blood glucose (FBG) substantially decreased in the control group compared to the HP group (-9.13 ± 0.67 versus -4.93 ± 1.4%; P = 0.01, resp.). Total cholesterol, systolic blood pressure (SBP), and diastolic blood pressure (DBP) decreased both in the HP and in the control diet groups (P = 0.06, P = 0.07, and P = 0.09, resp.); however, the results were marginally significant. Serum levels of hs-CRP were reduced both in the control (-0.08 ± 0.11%, P = 0.06) and in the high protein groups (-0.04 ± 0.09%, P = 0.06). The energy-restricted HP diet resulted in more beneficial effects on weight loss and reduction of waist circumference. CVD risk factors may improve with HP diets among overweight and obese women. When using isoenergetic weight loss diets, total cholesterol, hs-CRP, and SBP were marginally significantly reduced, independent of dietary protein content. This trial is registered with ClinicalTrials.gov NCT01763528.

Euglycemic agent-mediated hypothalamic transcriptomic manipulation in the N171-82Q model of Huntington disease is related to their physiological efficacy

Our aim was to employ novel analytical methods to investigate the therapeutic treatment of the energy regulation dysfunction occurring in a Huntington disease (HD) mouse model. HD is a neurodegenerative disorder that is characterized by progressive motor impairment and cognitive alterations. Changes in neuroendocrine function, body weight, energy metabolism, euglycemia, appetite function, and gut function can also occur. It is likely that the locus of these alterations is the hypothalamus. We determined the effects of three different euglycemic agents on HD progression using standard physiological and transcriptomic signature analyses. N171-82Q HD mice were treated with insulin, Exendin-4, and the newly developed GLP-1-Tf to determine whether these agents could improve energy regulation and delay disease progression. Blood glucose, insulin, metabolic hormone levels, and pancreatic morphology were assessed. Hypothalamic gene transcription, motor coordination, and life span were also determined. The N171-82Q mice exhibited significant alterations in hypothalamic gene transcription signatures and energy metabolism that were ameliorated, to varying degrees, by the different euglycemic agents. Exendin-4 or GLP-1-Tf (but not insulin) treatment also improved pancreatic morphology, motor coordination, and increased life span. Using hypothalamic transcription signature analyses, we found that the physiological efficacy variation of the drugs was evident in the degree of reversal of the hypothalamic HD pathological signature. Euglycemic agents targeting hypothalamic and energy regulation dysfunction in HD could potentially alter disease progression and improve quality of life in HD.

Omental gene expression of adiponectin correlates with degree of insulin sensitivity before and after gastric bypass surgery

BACKGROUND

Circulating adiponectin is known to correlate negatively with insulin resistance in patients with obesity and diabetes. The aim of this study was to assess the effect of gastric bypass (GB) surgery on adiponectin gene expression in subcutaneous and omental adipose tissues.

METHODS

Adipose tissues and plasma were obtained from 25 subjects undergoing GB surgery, 15 non-obese subjects, and 12 subjects after GB surgery. Real-time quantitative reverse transcription polymerase chain reaction was used for analysis of the adipose tissues. Adiponectin expression was normalized for glyceraldehyde 3-phosphate dehydrogenase and expressed as percentage of subject-matched subcutaneous expression which was given an arbitrary value of 100%. Insulin resistance was assessed by the homeostatic model assessment (HOMA). Circulating adiponectin was assayed by ELISA.

RESULTS

Omental adiponectin gene expression was fivefold higher in subjects after GB when compared with age-matched morbidly obese subjects before GB (P < 0.01). There were no statistical differences in omental adiponectin gene expression observed in subjects after GB and age-matched non-obese subjects. For the entire cohort of subjects, there was a significant negative correlation between omental adiponectin expression and insulin resistance expressed by HOMA values (r = -0.62, P < 0.001). Circulating adiponectin was significantly lower (P < 0.05) in the obese group than in the non-obese and post-GB groups.

CONCLUSIONS

Omental adiponectin gene expression significantly increases after GB surgery reaching levels equal to age-matched non-obese subjects. Omental adiponectin expression has a significant negative correlation with the insulin resistance status.

Significant associations of the rs2943634 (2q36.3) genetic polymorphism with adiponectin, high density lipoprotein cholesterol and ischemic stroke

BACKGROUND

rs2943634 C/A single nucleotide polymorphism (SNP), located in a non coding region of chromosome 2q36.3, has been associated with coronary artery disease in two genome wide association studies. Our goal was to investigate its relation with myocardial infarction (MI) and ischemic stroke (IS), as well as with 12 intermediate risk phenotypes, in a population-based prospective cohort study.

METHODS

rs2943634 was genotyped in a case-cohort study including a random sample of 1891 individuals (subcohort) and all incident MI (n=211) and IS (n=144) cases during a mean follow-up of 8.2±2.2years, nested within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort comprising 27,548 middle-aged men and women.

RESULTS

rs2943634 minor allele (A) was associated in an additive fashion with lower risk of IS but not with MI [hazard ratio (HR)=0.66; 95% confidence interval (CI): 0.50-0.87; P=0.003; HR=1.02; 95% CI: 0.82-1.28; P=0.83 respectively, for the age and sex adjusted model]. Furthermore, it was related to slightly higher levels of plasma adiponectin [CC 6.94, CA 7.27, AA 7.86μg/ml, P=0.0002] and high density lipoprotein (HDL)-cholesterol (CC 52.08, CA 53.05 and AA 55.27mg/dl, P=0.002), based on additive models. Adjustment for adiponectin and HDL-cholesterol did not attenuate the association between the SNP and IS risk. In contrast, adjustment for adiponectin abolished the association between the SNP and HDL-cholesterol and adjustment for HDL-cholesterol attenuated the association between the SNP and adiponectin.

CONCLUSIONS

Our findings suggest that rs2943634 is associated with IS risk and with plasma levels of HDL-cholesterol and adiponectin in this German population. Further investigations are needed to confirm these results and to clarify the mechanisms underlying the association.

Adiponectin levels and expression of adiponectin receptors in isolated monocytes from overweight patients with coronary artery disease

Background

Adiponectin has insulin-sensitizing and anti-atherosclerotic effects, partly mediated through its action on monocytes. We aimed to determine adiponectin levels and expression of its receptors (AdipoR1 and AdipoR2) in peripheral monocytes from overweight and obese patients with coronary artery disease (CAD).

Methods

Fifty-five overweight/obese patients, suspected for CAD, underwent coronary angiography: 31 were classified as CAD patients (stenosis ≥ 50% in at least one main vessel) and 24 as nonCAD. Quantitative RT-PCR and flow cytometry were used for determining mRNA and protein surface expression of adiponectin receptors in peripheral monocytes. A high sensitivity multiplex assay (xMAP technology) was used for the determination of plasma adiponectin and interleukin-10 (IL-10) secreted levels.

Results

Plasma adiponectin levels were decreased in CAD compared to nonCAD patients (10.9 ± 3.1 vs. 13.8 ± 5.8 μg/ml respectively, p = 0.033). In multivariable analysis, Matsuda index was the sole independent determinant of adiponectin levels. AdipoR1 and AdipoR2 protein levels were decreased in monocytes from CAD compared to nonCAD patients (59.5 ± 24.9 vs. 80 ± 46 and 70.7 ± 39 vs. 95.6 ± 47.8 Mean Fluorescence Intensity Arbitrary Units respectively, p < 0.05). No significant differences were observed concerning the mRNA levels of the adiponectin receptors between CAD and nonCAD patients. AdipoR2 protein levels were positively correlated with plasma adiponectin and Matsuda index (r = 0.36 and 0.31 respectively, p < 0.05 for both). Furthermore, basal as well as adiponectin-induced IL-10 release was reduced in monocyte-derived macrophages from CAD compared to nonCAD subjects.

Conclusions

Overweight patients with CAD compared to those without CAD, had decreased plasma adiponectin levels, as well as decreased surface expression of adiponectin receptors in peripheral monocytes. This fact together with the reduced adiponectin-induced IL-10 secretion from CAD macrophages could explain to a certain extent, an impaired atheroprotective action of adiponectin.

Serum adiponectin is associated with homocysteine in elderly men and women, and with 5,10-methylenetetrahydrofolate reductase (MTHFR) in a sex-dependent manner

Plasma homocysteine associates positively with cardiovascular disease. C-to-T substitution at base 677 of the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene associates with increased plasma homocysteine. The association of adiponectin with cardiovascular disease is unclear. This study of survivors of a 30-year cohort of the Jewish Israeli population, 310 men and 273 women (mean age, 70.5 ± 7.0 years for both), investigated the relationship between adiponectin and homocysteine, and between adiponectin and the MTHFR C677T genotype. Serum adiponectin associated positively with total homocysteine in both men (r = 0.27, P < .001) and women (r = 0.22, P < .001). In women, the TT MTHFR genotype associated with lower median adiponectin levels, 8.98 mg/L, compared with 9.88 and 10.57 mg/L for TC and CC, respectively (P = .05; CC vs TT, P = .01). In men, the trend was opposite, but not statistically significant: 7.90, 7.03, and 6.88 mg/L for TT, TC, and CC genotypes, respectively (P = .5). This study demonstrated a positive association between homocysteine and adiponectin in both elderly men and women and a statistically significant association between adiponectin and MTHFR C677T genotypes in women only.

Association between plasma adiponectin and high-density lipoprotein cholesterol in postmenopausal women

OBJECTIVES

We investigated the association of plasma adiponectin and high-density lipoprotein cholesterol (HDL-C) in postmenopausal women.

DESIGN AND METHODS

This was a cross-sectional study of 563 postmenopausal women with and 1029 without low HDL-C. Lipid profile, glucose, adiponectin, IL-1beta, IL-6, and TNF-alpha concentrations were measured.

RESULTS

Plasma adiponectin levels increased with age in elderly women. Plasma adiponectin levels were lower in subjects with low HDL-C (<50mg/dl), when compared with normal HDL-C subjects. In multiple stepwise linear regression analysis, adiponectin was a significant independent predictor of HDL-C concentration with body mass index, total cholesterol, and triglycerides. Values in the third and fourth quartile of adiponectin were associated with decreased odds ratio for low HDL-C (0.62; 95% CI, 0.44-0.87, 0.40; 95% CI, 0.27-0.58, respectively) when compared with values in the lowest quartile after multivariable adjustment.

CONCLUSIONS

Adiponectin was significantly associated with HDL-C concentration in postmenopausal women. These findings suggest that high adiponectin levels may have a protective effect on atherosclerosis with increasing HDL-C in postmenopausal women.

Exendin-4 improves glycemic control, ameliorates brain and pancreatic pathologies, and extends survival in a mouse model of Huntington's disease

OBJECTIVE

The aim of this study was to find an effective treatment for the genetic form of diabetes that is present in some Huntington's disease patients and in Huntington's disease mouse models. Huntington's disease is a neurodegenerative disorder caused by a polyglutamine expansion within the huntingtin protein. Huntington's disease patients exhibit neuronal dysfunction/degeneration, chorea, and progressive weight loss. Additionally, they suffer from abnormalities in energy metabolism affecting both the brain and periphery. Similarly to Huntington's disease patients, mice expressing the mutated human huntingtin protein also exhibit neurodegenerative changes, motor dysfunction, perturbed energy metabolism, and elevated blood glucose levels.

RESEARCH DESIGN AND METHODS

Huntington's disease mice were treated with an FDA-approved antidiabetic glucagon-like peptide 1 receptor agonist, exendin-4 (Ex-4), to test whether euglycemia could be achieved, whether pancreatic dysfunction could be alleviated, and whether the mice showed any neurological benefit. Blood glucose and insulin levels and various appetite hormone concentrations were measured during the study. Additionally, motor performance and life span were quantified and mutant huntingtin (mhtt) aggregates were measured in both the pancreas and brain.

RESULTS

Ex-4 treatment ameliorated abnormalities in peripheral glucose regulation and suppressed cellular pathology in both brain and pancreas in a mouse model of Huntington's disease. The treatment also improved motor function and extended the survival time of the Huntington's disease mice. These clinical improvements were correlated with reduced accumulation of mhtt protein aggregates in both islet and brain cells.

CONCLUSIONS

Targeting both peripheral and neuronal deficits, Ex-4 is an attractive agent for therapeutic intervention in Huntington's disease patients suffering from diabetes.

The metabolic syndrome

The "metabolic syndrome" (MetS) is a clustering of components that reflect overnutrition, sedentary lifestyles, and resultant excess adiposity. The MetS includes the clustering of abdominal obesity, insulin resistance, dyslipidemia, and elevated blood pressure and is associated with other comorbidities including the prothrombotic state, proinflammatory state, nonalcoholic fatty liver disease, and reproductive disorders. Because the MetS is a cluster of different conditions, and not a single disease, the development of multiple concurrent definitions has resulted. The prevalence of the MetS is increasing to epidemic proportions not only in the United States and the remainder of the urbanized world but also in developing nations. Most studies show that the MetS is associated with an approximate doubling of cardiovascular disease risk and a 5-fold increased risk for incident type 2 diabetes mellitus. Although it is unclear whether there is a unifying pathophysiological mechanism resulting in the MetS, abdominal adiposity and insulin resistance appear to be central to the MetS and its individual components. Lifestyle modification and weight loss should, therefore, be at the core of treating or preventing the MetS and its components. In addition, there is a general consensus that other cardiac risk factors should be aggressively managed in individuals with the MetS. Finally, in 2008 the MetS is an evolving concept that continues to be data driven and evidence based with revisions forthcoming.

Visceral adipose tissue, adiponectin levels and insulin resistance are related to atherosclerosis as assessed by whole-body magnetic resonance angiography in an elderly population

OBJECTIVE

The principal aim of this study was to determine whether the amount of visceral adipose tissue (VAT) is more related than subcutaneous adipose tissue (SAT) to atherosclerosis assessed by whole-body MRA (WBMRA). A further objective was to investigate whether traditional risk factors, inflammation, or adipokines could explain the hypothesized relationship between VAT and atherosclerosis.

METHODS

Men and women aged 70 were recruited from the general population into the Prospective Investigation of The Vasculature in Uppsala Seniors (PIVUS) and 306 of them underwent WBMRA in a clinical 1.5-T scanner. The arterial tree was assessed for degree of stenosis or occlusion and a total atherosclerotic score (TAS) was established. Information on risk factors and BMI and on SAT and VAT, segmented on an axial MR scan was collected. Adiponectin, leptin, and high sensitive C-reactive protein (hsCRP) were measured in serum. HOMA index was used as a marker of insulin resistance.

RESULTS

VAT was related to TAS independently of gender, total obesity (BMI), amount of SAT, hsCRP and also to the traditional risk factors included in the Framingham risk score (FRS) in an elderly population. Adiponectin or the HOMA insulin resistance, but not leptin or VAT, together with FRS was significantly related to TAS in a multiple censored regression model.

CONCLUSION

Adiponectin attenuated the relationship between VAT and TAS, suggesting that adiponectin and insulin resistance is an important link between visceral adiposity and atherosclerosis.

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.

Adiponectin inversely correlates with high sensitive C-reactive protein and triglycerides, but not with insulin sensitivity, in apparently healthy Japanese men

Adiponectin, an antiatherogenic peptide, has diverse biological actions on insulin sensitivity, inflammation and lipid metabolism. To explore physiological and pathophysiological significance of adiponectin in the Japanese general population, we systematically analyzed the relationship between adiponectin and high sensitive CRP (hsCRP), lipids, insulin sensitivity, and anthropometric parameters in 166 consecutive adult male health examinees. By univariate analysis, serum adiponectin was positively correlated with age and HDL-cholesterol, and inversely correlated with fasting plasma glucose, fasting insulin, homeostasis model assessment insulin-resistance, waist, body mass index, triglycerides and hsCRP. However, multivariate analysis revealed that adiponectin independently correlated with triglycerides (r = -0.243, P = 0.0033) and hsCRP (r = -0.262, P = 0.0015) but not with all other variables. Adiponectin was lower and hsCRP higher in the subjects with metabolic syndrome (n = 22) than in those without it (n = 144) (adiponectin, 5.4 +/- 2.8 vs 7.5 +/- 4.2 microg/ml, p = 0.002; hsCRP, 832 +/- 605 vs 470 +/- 524 ng/ml, p = 0.0004). Current findings suggest that relative importance of hypertriglyceridemia and enhanced inflammation, rather than insulin resistance, as the downstream events of hypoadiponectinemia leading to atherosclerosis in the Japanese general population.