High-molecular-weight adiponectin does not predict cardiovascular events in patients with type 2 diabetes

Relationship between adiponectin multimer levels and subtypes of cerebral infarction

Aim

Serum adiponectin levels are decreased in patients with cerebral infarction. Adiponectin in circulation exists in three isoforms: high molecular weight (HMW), medium molecular weight (MMW), and low molecular weight (LMW) adiponectin. We measured serum levels of total adiponectin and adiponectin multimers (HMW, MMW, and LMW) in patients with cerebral infarction and compared the serum levels of the three adiponectin multimers in stroke subtypes. We also evaluated the clinical value of adiponectin multimer levels as a biomarker for cerebral infarction.

Methods

We assessed a total of 132 patients with cerebral infarctions. The serum levels of total and adiponectin multimers were measured using enzyme-linked immunosorbent assay (ELISA).

Results

The total and HMW adiponectin levels were significantly lower in atherothrombotic infarction (AI) than in cerebral embolism (CE) (total, p < 0.05; HMW, p < 0.05). In male patients, the MMW adiponectin level was significantly lower in the lacunar infarction (LI) group than in the AI group (p < 0.05). The LMW adiponectin level was significantly lower in the AI group than in the LI and CE groups (LI, p < 0.001; CE, p = 0.001). However, there were no significant differences in adiponectin multimer levels among the stroke subtypes in female subjects. Additionally, in female patients with AI and LI, the LMW adiponectin levels were negatively associated with C-reactive protein (CRP; AI, p < 0.05; LI, p < 0.05).

Conclusion

These findings suggest that a decrease in adiponectin is associated with AI and that serum LMW adiponectin level represents a potential biomarker for AI.

Lower Levels of Circulating Adiponectin in Elderly Patients with Metabolic Inflammatory Syndrome: A Cross-Sectional Study

BACKGROUND

Metabolic inflammation plays an important role in the pathogenesis of atherosclerosis, type 2 diabetes, non-alcoholic fatty liver disease, and obesity. The above metabolic disorders often coexist and are closely related with systemic low-grade inflammation. Metabolic inflammatory syndrome (MIS), a cluster of these four metabolic disorders, is a novel concept that is thought to be a better predictor of coronary heart disease than metabolic syndrome. Adiponectin is an adipokine that increases insulin sensitivity and antioxidation as well as has an anti-atherosclerosis effect. It is unclear whether adiponectin is associated with MIS. The objective of this study was to assess whether circulating adiponectin can be used as an indicator for MIS in elderly adults.

METHODS

A total of 136 elderly inpatients were divided into two groups: the MIS group and the non-MIS group. Characteristics, inflammatory markers, blood lipid metabolism, insulin resistance, and circulating adiponectin levels were assessed and compared between the two groups. Logistic regression analysis was used to explore the association between the associated factors and MIS.

RESULTS

MIS patients were more likely to have a higher body mass index, have a higher fasting blood glucose level, be smokers, have fundus arteriosclerosis, have lower levels of adiponectin (4044.90 ± 3906.82 ng/mL vs 8503.89 ± 3523.89 ng/mL, p < 0.001), and have higher levels of inflammation (white blood cell and C-reactive protein) than non-MIS patients. Multiple factor analysis showed that lower adiponectin levels (OR = 22.937, p < 0.001) were independently associated with MIS. Adiponectin levels were lower in the vascular disease (2673.29 ± 1930.05 ng/mL vs 7194.38 ± 4615.83 ng/mL, p = 0.001), atherosclerosis (2374.14 [1496.41-4263.90] ng/mL vs 6037.48 [3865.61-10,373.60] ng/mL, p < 0.001), and type 2 diabetes (2391.73 [1386.41-4069.68] ng/mL vs 8916.03 [5801.14-12,724.45] ng/mL, p < 0.001) subgroups than in the non-MIS group.

CONCLUSION

Lower adiponectin levels in serum are associated with MIS. Low adiponectin may be used as a biomarker for atherosclerosis in patients with MIS.

Adiponectin and Its Isoforms in Pathophysiology

Adiponectin circulates in blood in multiple isoforms. High molecular weight (HMW) adiponectin is thought to be most biologically active and promotes glucose uptake, insulin sensitivity, and fatty acid oxidation. In obesity, adiponectin isoform formation is disrupted, leading to an inverse association between metabolic disease and HMW and total adiponectin. Adiponectin isoforms also function as acute-phase reactants influencing inflammation in acute and chronic disease. Interestingly, adiponectin and mortality have a U-shaped association. Unfortunately, data concerning adiponectin and its pathophysiologic function conflict. This is predominantly due to difficulties in adequate measurement of adiponectin isoforms and lack of a gold standard. In this review we provide a general overview of the formation and function of adiponectin and its isoforms under physiologic conditions. We highlight the ways adiponectin isoform formation is disrupted in obesity and its ensuing pathologic conditions. Furthermore, we will elaborate on the role of adiponectin isoforms as inflammatory proteins with respect to cardiac and kidney disease and discuss the association of adiponectin with mortality. Finally, we will provide a historical perspective on the measurement of adiponectin isoforms, current limitations, and future challenges.

Is There Any Relationship between Plasma 25-Hydroxyvitamin D₃, Adipokine Profiles and Excessive Body Weight in Type 2 Diabetic Patients?

A growing interest in the role of vitamin D in metabolic diseases led us to study the relationships between 25-hydroxyvitamin D₃ (25(OH)D₃) and the profiles of selected adipokines in type 2 diabetic (T2DM) patients. The study comprised 92 type 2 diabetics divided into quartiles regarding 25(OH)D₃ concentration. Each group was divided into male and female subgroups. All the studied patients had their anthropometric and biochemical parameters determined. Plasma 25-hydroxyvitamin D₃ concentration was determined by HPLC, while the selected adipokines (leptin, adiponectin, resistin and visfatin) by ELISA methods. The ratio of leptin to adiponectin (L/A) was calculated for all the patients. In 85.3% of diabetics a full (<20 ng/mL) or moderate (20-30 ng/mL) vitamin D deficit was found. Irrespective of sex, plasma leptin concentration decreased across increasing quartiles of 25(OH)D₃ level. In women, 25(OH)D₃ was negatively correlated with BMI, leptin level as well as L/A ratio, and positively with adiponectin concentration. In men, 25(OH)D₃ was positively correlated with HDL and negatively with systolic blood pressure (SBP), leptin level and L/A ratio. Considering all the patients, there ocurred a significant negative correlation between 25(OH)D₃ and SBP, BMI, WHR, TG, leptin and L/A ratio and positive ones between 25(OH)D₃ and both adiponectin and HDL. The results of the study support the existence of the relationship among vitamin D, obesity and leptin in type 2 diabetic patients.

Gender difference in adiponectin associated with cardiovascular mortality

Background

It is important to identify cardiovascular diseases in patients at high risk. To include genetics into routine cardiological patients has therefore been discussed recently.

We wanted to evaluate the association between high-molecular weight adiponectin and cardiovascular risk, and secondly in the same population evaluate if specific genotype differences regarding risk could be observed, and thirdly if gender differences could be seen.

Method

Four hundred seventy-six elderly participants recruited from a rural community were included. All participants underwent a clinical examination, echocardiography, and blood sampling and the single nucleotide polymorphism (SNP) (rs266729) of adiponectin was analysed. Follow-up time was 6.7 years.

Results

Those with high serum concentration of adiponectin had a more 2 fold increased cardiovascular risk, and it might be that females exhibits even higher risk where a more than 5 fold increased risk could be seen. The result could be demonstrated even in a multivariate model adjusting for well-known clinical risk factors. However, as the sample size was small the gender differences should be interpreted with caution. In the genotype evaluation the C/C carriers of the female group had a more than 9-fold increased risk of cardiovascular mortality, however the confidence interval was wide. Such genotype difference could not be found in the male group.

Conclusion

High level of adiponectin was associated with increased cardiovascular risk. Also a gender difference in the genotype evaluation could be seen where the C/C carriers obtained higher risk in the female group but not in the male group. Thus, in order to identify patients at risk early, genetic analyses may add to the armamentarium used in the clinical routine. However, information should be regarded as hypothesis generating as the sample size was small and should stimulate further research in individualized cardiovascular prevention and treatment.

Circulating adiponectin and cardiovascular mortality in patients with type 2 diabetes mellitus: evidence of sexual dimorphism

BACKGROUND

The pathogenesis of cardiovascular (CV) mortality, whose rate is increased in type 2 diabetes, is poorly understood.

METHODS

Three prospective cohorts were analyzed: 1) Gargano Heart Study (GHS; 359 patients, 58 events/1,934 person-years; py); 2) Health Professional Follow-up Study (HPFS; 833 men, 146 events/10,024 py); 3) Nurses' Health Study (NHS; 902 women, 144 events/15,074 py).

RESULTS

In GHS serum adiponectin predicted CV mortality in men (hazard ratio, HR, and 95% CI per standard deviation, SD, increment = 1.54, 1.19-2.01), but not women (HR = 0.98, 0.48-2.01).

CONCLUSIONS

This is the first report showing that high circulating adiponectin predicts increased CV mortality in men, but not in women with type 2 diabetes. Further studies are necessary to unravel the mechanisms through which adiponectin influences CV mortality in a sex-specific manner.

Association between HMW adiponectin, HMW-total adiponectin ratio and early-onset coronary artery disease in Chinese population

OBJECTIVE

Adiponectin is an adipose-secreting protein that shows atheroprotective property and has inverse relation with coronary artery disease (CAD). High-molecular weight (HMW) adiponectin is reported as the active form of adiponectin. In the present study, we aimed to investigate the association between total adiponectin, HMW adiponectin, HMW-total adiponectin ratio and the severity of coronary atherosclerosis, and to compare their evaluative power for the risk of CAD.

METHODS

Serum levels of total and HMW adiponectin were measured in 382 early-onset CAD (EOCAD) patients and 305 matched controls undergoing coronary angiography by enzyme-linked immunosorbent assay (ELISA). Gensini score was used to evaluate the severity of coronary atherosclerosis.

RESULTS

CAD onset age was positively correlated with HMW adiponectin (r = 0.383, P < 0.001) and HMW-total adiponectin ratio (r = 0.429, P < 0.001) in EOCAD patients. Total and HMW adiponectin and HMW-total adiponectin ratio were all inversely correlated with Gensini score (r = -0.417, r = -0.637, r = -0.578, respectively; all P < 0.001). Multivariate binary logistic regression analysis demonstrated that HMW adiponectin and HMW-total adiponectin ratio were both inversely correlated with the risk of CAD (P < 0.05). ROC analysis indicated that areas under the ROC curves of HMW adiponectin and HMW-total adiponectin ratio were larger than that of total adiponectin (P < 0.05).

CONCLUSIONS

Adiponectin is cardioprotective against coronary atherosclerosis onset in EOCAD patients. HMW adiponectin and HMW-total adiponectin ratio show stronger negative associations with the severity of coronary atherosclerosis than total adiponectin does. HMW adiponectin and HMW-total adiponectin ratio are effective biomarkers for the risk of CAD in Chinese population.

Association between adiponectin concentrations and cardiovascular disease in diabetic patients: a systematic review and meta-analysis

Background

This systematic review and meta-analysis of prospective studies evaluates the association between adiponectin concentrations and risk of cardiovascular disease (CVD) in individuals with diabetes mellitus (DM).

Methods

PubMed and Embase were searched for prospective studies on the association of adiponectin concentrations and risk of CVD up to June 2013. Random-effect model was selected to pool the relative risk (RR) and 95% CI.

Results

Five prospective cohort studies and one nested case-control studies met the included criterion. The estimated summary RR and 95% CI of five prospective cohort studies for type 2 diabetes comparing top vs low tertile of adiponectin concentrations was 0.99 (95% CI: 0.67–1.45), with significant heterogeneity between studies (p = 0.037, I² = 60.9%). This heterogeneity was explained by one study conducted in Korean.

Conclusions

This study represents the first meta-analysis between adiponectin levels and CVD in diabetic patients and indicated no association was found. This result should be verified further by large sample size, long duration of follow-up, and well-designed prospective clinical trials.

Adiponectin and all-cause mortality in elderly people with type 2 diabetes

OBJECTIVE

To assess the association between serum adiponectin level and all-cause mortality in people with type 2 diabetes. Because of the insulin-sensitizing, anti-inflammatory, and antiatherogenic effects of adiponectin, we hypothesized that higher adiponectin level would be associated with lower all-cause mortality.

RESEARCH DESIGN AND METHODS

A total of 609 men and women aged 72 ± 6.3 years with type 2 diabetes and information on total and high molecular weight adiponectin were followed for a median of 5 years. The longitudinal association between adiponectin and all-cause mortality was analyzed with Cox proportional hazards models with time from adiponectin measurement to death as the time-to-event variable. Analyses were adjusted for demographic variables and significant diabetes parameters, significant cardiovascular parameters, and significant diabetes medications.

RESULTS

Total and high molecular weight adiponectin were highly correlated. The highest adiponectin quartile was strongly associated with higher all-cause mortality compared with the lowest quartile (hazard ratio = 4.0 [95% CI: 1.7-9.2]) in the fully adjusted model. These results did not change in analyses stratified by sex and thiazolidinedione use, after exclusion of people who died within one year of adiponectin measurement, or when change in weight before adiponectin measurement was considered.

CONCLUSIONS

Contrary to our hypothesis, higher adiponectin level was related to higher all-cause mortality. This association was not explained by confounding by other characteristics, including medications or preceding weight loss.

ADIPOQ and adiponectin: the common ground of hyperglycemia and coronary artery disease?

Plasma adiponectin and the coding gene for adiponectin, ADIPOQ, are thought to explain part of the interaction between obesity, insulin resistance, type 2 diabetes (T2DM) and coronary artery disease (CAD). Here, we illustrate the role that adiponectin and ADIPOQ variants might play in the modulation of CAD, especially in the occurrence of hyperglycemia. Recent evidence suggests that total and high molecular weight (HMW) adiponectin levels are apparent markers of better cardiovascular prognosis in patients with low risk of CAD. However, in subjects with established or high risk of CAD, these levels are associated with poorer prognosis. We also provide recent evidences relating to the genetic control of total and HMW adiponectin levels, especially evidence regarding ADIPOQ. Accumulated data suggest that both adiponectin levels and polymorphisms in the ADIPOQ gene are linked to the risk of CAD in patients with hyperglycemia, and that these associations seem to be independent from each other, even if adiponectin levels are partly dependent on ADIPOQ.

Determinants of serum high molecular weight (HMW) adiponectin levels in patients with coronary artery disease: associations with cardio-renal-anemia syndrome

OBJECTIVE

A low serum adiponectin level is associated with a high incidence of coronary artery disease (CAD) in the healthy population. Paradoxically, serum adiponectin is elevated in patients with severe CAD or chronic heart failure. We investigated the determinants of serum high molecular weight (HMW) adiponectin in patients with CAD.

PATIENTS AND METHODS

We studied 228 consecutive patients with CAD confirmed by angiography. Anemia was defined as a hemoglobin of <13.0 g/dL in men and<12.0 g/dL in women. A high plasma B-type natriuretic-peptide (BNP) was defined as >100 pg/mL. Chronic kidney disease (CKD) was defined as an estimated glomerular filtration rate (eGFR) of <60 mL/min for more than 3 months. The patients with CAD were divided into eight groups according to the presence or absence of anemia, high BNP, and/or CKD.

RESULTS

In all 228 patients with CAD, serum HMW adiponectin correlated positively with age, high-density-lipoprotein cholesterol (HDL-C), and BNP, while this parameter showed negative correlations with body mass index, insulin resistance, triglycerides, eGFR, and hemoglobin. Multivariate analysis showed that HDL-C, BNP, gender, and age were independently associated with the HMW adiponectin. Serum HMW adiponectin was lower in CAD patients with than without metabolic syndrome. Serum HMW adiponectin and the HMW/total adiponectin ratio were highest in CAD patients who had anemia, high BNP, and CKD among the groups.

CONCLUSION

In patients with CAD, metabolic syndrome is associated with a lower serum HMW adiponectin, while the presence of anemia, high BNP, and CKD is associated with elevation of the serum HMW adiponectin.

Anemia is associated with an elevated serum level of high-molecular-weight adiponectin in patients with type 2 diabetes independently of renal dysfunction

Low serum adiponectin is associated with a high incidence of type 2 diabetes or coronary artery disease in the general population. Paradoxically, serum adiponectin is elevated in patients with chronic kidney disease (CKD), such as overt diabetic nephropathy. The current study aimed to investigate whether anemia was independently associated with the serum level of high-molecular-weight (HMW) adiponectin in patients with type 2 diabetes. We studied 207 type 2 diabetic patients (92 women and 115 men). Anemia was defined as a hemoglobin (Hb) <13.0g/dL in men and <12.0g/dL in women according to the guidelines of the World Health Organization (WHO). Overt nephropathy (CKD) was defined as clinical proteinuria and /or estimated glomerular filtration rate (eGFR) lower than 60mL/min for more than 3 months. The diabetic patients were divided into 4 groups according to the presence or absence of anemia and/or CKD. Serum HMW adiponectin levels were measured by a sandwich enzyme-linked immunosorbent assay. In all 207 patients with type 2 diabetes, serum total and HMW adiponectin levels were correlated positively with age, the duration of diabetes, high-density lipoprotein (HDL) cholesterol, urinary albumin, and serum erythropoietin, whereas negative correlations were found with body mass index, triglyceride, eGFR, Hb, hematocrit, and high sensitivity C-reactive protein. A stepwise regression analysis demonstrated that among several significant variables, Hb had the strongest independent influence on HMW adiponectin (beta =-0.487, P < 0.001). Diabetic patients of both sexes with anemia and CKD had the highest serum levels of HMW adiponectin among the 4 groups. In conclusion, anemia is associated with marked elevation of serum HMW adiponectin levels in diabetic patients who have CKD, and this elevation is independent of renal function.