Adiponectin at Physiologically Relevant Concentrations Enhances the Vasorelaxative Effect of Acetylcholine via Cav-1/AdipoR-1 Signaling

Serum Adiponectin Levels Increase in Acute Ischemic Stroke and Correlate with Patients' Outcomes: A Pilot Study

Stroke is a leading cause of death and severe disability worldwide. Rapid diagnosis is critical to ensure the timely administration of medical treatment. Given that in some cases CT scans fail to show the classic clinical signs of stroke, we aimed to evaluate the diagnostic capacity of adiponectin levels and their association with the clinical parameters of patients with acute ischemic stroke (AIS). Adiponectin was measured within 24 h (T1) and 48 h (T2) of AIS onset in 70 patients. A total of 68 control cases were included in the study. Adiponectin levels were significantly higher in the AIS patients than in the controls (16.64 (3.79; 16.69) vs. 3.78 (3.79; 16.69); p < 0.001), with an accuracy of 0.98 (AUC = 0.99). Lower levels were seen in males and in AIS patients with obesity. Higher levels of adiponectin at T1 were associated with a moderate/severe NIHSS score at patient discharge. Moreover, higher levels of borderline significance were seen in patients who died within 12 months of their AIS episode (p = 0.054). Adiponectin may be a useful biomarker for the identification of AIS patients who do not present classic CT signs and could be used to stratify severe cases. Further studies are needed to validate these results.

The Association between Serum Adiponectin Levels and Endothelial Function in Non-Dialysis-Dependent Chronic Kidney Disease Patients

Adiponectin is the richest human circulating adipokine with anti-inflammatory, antioxidant, and insulin-sensitizing effects. We evaluated the association between serum adiponectin levels and endothelial function in chronic kidney disease (CKD) patients, obtaining fasting blood samples from 130 non-dialysis CKD subjects. We measured the endothelial function-represented by the vascular reactivity index (VRI)-via non-invasive digital thermal monitoring, and serum adiponectin concentrations by enzyme immunoassay kits. A total of 22 (16.9%), 39 (30.0%), and 69 (53.1%) patients had poor (VRI < 1.0), intermediate (1.0 ≤ VRI < 2.0), and good (VRI ≥ 2.0) vascular reactivity. Elevated serum blood urea nitrogen (BUN) level was negatively correlated with VRI values, but serum adiponectin and estimated glomerular filtration rate were positively associated with VRI values by univariate linear regression analysis. After applying multivariate stepwise linear regression analysis adjustment, the significantly positive association of adiponectin (p < 0.001), and the significantly negative association of log-BUN (p = 0.021) with VRI values in CKD subjects remained. In an animal study using in vitro blood-vessel myography, treatment with adiponectin enhancing acetylcholine-mediated vasorelaxation in 5/6 nephrectomy CKD mice. Our study results indicated that adiponectin concentration was positively associated with VRI values and modulated endothelial function in non-dialysis CKD patients.

The importance of caveolin as a target in the prevention and treatment of diabetic cardiomyopathy

The diabetic population has been increasing in the past decades and diabetic cardiomyopathy (DCM), a pathology that is defined by the presence of cardiac remodeling and dysfunction without conventional cardiac risk factors such as hypertension and coronary heart diseases, would eventually lead to fatal heart failure in the absence of effective treatment. Impaired insulin signaling, commonly known as insulin resistance, plays an important role in the development of DCM. A family of integral membrane proteins named caveolins (mainly caveolin-1 and caveolin-3 in the myocardium) and a protein hormone adiponectin (APN) have all been shown to be important for maintaining normal insulin signaling. Abnormalities in caveolins and APN have respectively been demonstrated to cause DCM. This review aims to summarize recent research findings of the roles and mechanisms of caveolins and APN in the development of DCM, and also explore the possible interplay between caveolins and APN.

Thermal dysregulation in patients with multiple sclerosis during SARS-CoV-2 infection. The potential therapeutic role of exercise

Thermoregulation is a homeostatic mechanism that is disrupted in some neurological diseases. Patients with multiple sclerosis (MS) are susceptible to increases in body temperature, especially with more severe neurological signs. This condition can become intolerable when these patients suffer febrile infections such as coronavirus disease-2019 (COVID-19). We review the mechanisms of hyperthermia in patients with MS, and they may encounter when infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Finally, the thermoregulatory role and relevant adaptation to regular physical exercise are summarized.

Role of Perivascular Adipose Tissue-Derived Adiponectin in Vascular Homeostasis

Studies of adipose tissue biology have demonstrated that adipose tissue should be considered as both passive, energy-storing tissue and an endocrine organ because of the secretion of adipose-specific factors, called adipokines. Adiponectin is a well-described homeostatic adipokine with metabolic properties. It regulates whole-body energy status through the induction of fatty acid oxidation and glucose uptake. Adiponectin also has anti-inflammatory and antidiabetic properties, making it an interesting subject of biomedical studies. Perivascular adipose tissue (PVAT) is a fat depot that is conterminous to the vascular wall and acts on it in a paracrine manner through adipokine secretion. PVAT-derived adiponectin can act on the vascular wall through endothelial cells and vascular smooth muscle cells. The present review describes adiponectin's structure, receptors, and main signaling pathways. We further discuss recent studies of the extent and nature of crosstalk between PVAT-derived adiponectin and endothelial cells, vascular smooth muscle cells, and atherosclerotic plaques. Furthermore, we argue whether adiponectin and its receptors may be considered putative therapeutic targets.

Vascular Protection by Exercise in Obesity: Inflammasome-associated Mechanisms

PURPOSE

The nodlike receptor family pyrin domain containing 3 (NLRP3) inflammasome is a critical player in vascular pathology as it regulates caspase-1-mediated interleukin (IL)-1β processing. Physical activity ameliorates obesity-induced inflammation and vascular dysfunction, but the mechanisms responsible for these positive changes are incompletely understood. Here, the protective effect of physical activity on the inflammasome-associated vascular dysfunction in obesity and its putative mechanisms were investigated.

METHODS

Mice were fed a control low-fat diet (LFD) or a high-fat diet (HFD; 45% of calories from fat) and provided with running wheel access (LF-RUN or HF-RUN) or denied wheel access for our sedentary condition (LF-SED or HF-SED). The NLRP3 inflammasome-associated pathway, including NLRP3, caspase-1, and IL-1β, in mice aorta was examined by RT-qPCR and FLICA and DAB staining. The protein expression of zonula occluden-1 (ZO-1), ZO-2, adiponectin (APN), and adiponectin receptor 1 (AdipoR1) in aortic endothelial cells was determined by immunofluorescence double staining. Intracellular reactive oxidative stress and nitric oxide (NO) production were monitored with fluorescence probes, dihydroethidium, and diaminofluorecein.

RESULTS

HFD increased caspase-1 and IL-1β at mRNA and protein levels in endothelial cells of the aorta, and this was attenuated by voluntary running. HFD decreased ZO-1 and ZO-2 expression and reduced APN and AdipoR1 signaling; these were restored by running. The elevated intracellular superoxide (O2) production observed in HF-SED was ameliorated in HF-RUN. Finally, HF-RUN improved NO production in the aorta compared with HF-SED.

CONCLUSIONS

Our findings suggest that voluntary running ameliorates mechanisms associated with vascular dysfunction by suppressing NLRP3 inflammasome, improving NO production, and reducing oxidative stress. Such benefits of physical activity may be, at least in part, associated with APN-AdipoR1 signaling and tight junction protein expression.

Effects of combined exercise training and Chlorella intake on vasorelaxation mediated by nitric oxide in aged mice

Chronic Chlorella intake and aerobic exercise training reduce arterial stiffness and increase circulating nitric oxide (NO) levels, which has beneficial effects. This study aimed to clarify the combined aortic NO-mediated effects of chronic Chlorella intake and aerobic exercise training on endothelial vasorelaxation in aged mice. In this study, 38-week-old male senescence-accelerated mouse prone 1 (SAMP1) mice were divided into aged sedentary control (Con), aerobic exercise training (AT; voluntary wheel running for 12 weeks), Chlorella intake (CH; 0.5% Chlorella powder in normal diet), and AT and CH combined (AT+CH) groups. Endothelium-dependent vasorelaxation by addition of acetylcholine to the isolated mouse aortic rings was significantly higher in the AT, CH, and AT+CH groups than in the Con group; a significantly greater effect was seen in the AT+CH group than in the AT and CH groups. Similarly, plasma and arterial nitrite/nitrate levels and arterial endothelial NO synthase phosphorylation were significantly higher in the AT, CH, and AT+CH groups than in the Con group; the AT+CH group had higher values than the AT and CH groups. Thus, chronic Chlorella intake combined with aerobic exercise training had pronounced effects on endothelial vasorelaxation in aged mice via an additive increase in arterial NO production. Novelty: Endothelium-dependent vasorelaxation was improved by Chlorella intake and exercise. Chlorella intake and exercise increased arterial Akt/eNOS/NO signaling. This combination approach further improved vasorelaxation via arterial NO production.

Aerobic exercise training-induced irisin secretion is associated with the reduction of arterial stiffness via nitric oxide production in adults with obesity

This study aimed to clarify whether muscle-derived irisin secretion induced by aerobic exercise training is involved in reduction of arterial stiffness via arterial nitric oxide (NO) productivity in obesity. In animal study, 16 Otsuka Long-Evans Tokushima Fatty (OLETF) rats with obesity were randomly divided into 2 groups: sedentary control (OLETF-CON) and 8-week aerobic treadmill training (OLETF-EX) groups. In human study, 15 subjects with obesity completed 8-week aerobic exercise training for 45 min at 60%-70% peak oxygen uptake intensity for 3 days/week. As a result of animal study, carotid-femoral pulse wave velocity (cfPWV) was decreased, and arterial phosphorylation levels of AMP-activated protein kinase (AMPK), protein kinase B (Akt), and endothelial NO synthase (eNOS), circulating levels of nitrite/nitrate (NOx) and irisin, and muscle messenger RNA expression of fibronectin type III domain containing 5 (Fndc5) were increased in the OLETF-EX group compared with OLETF-CON group. In a human study, regular aerobic exercise reduced cfPWV and elevated circulating levels of NOx and irisin. Furthermore, change in circulating irisin levels by regular exercise was positively correlated with circulating NOx levels and was negatively correlated with cfPWV. Thus, aerobic exercise training-induced increase in irisin secretion may be related to reduction of arterial stiffness achieved by NO production via activated arterial AMPK-Akt-eNOS signaling pathway in obesity. Novelty Aerobic exercise training promoted irisin secretion with upregulation of muscle Fndc5 gene expression in rats with obesity. Irisin affected the activation of arterial AMPK-Akt-eNOS signaling by aerobic exercise training. Increased serum irisin level by aerobic exercise training was associated with reduction of arterial stiffness in obese adults.

Adipose Tissue Distribution, Inflammation and Its Metabolic Consequences, Including Diabetes and Cardiovascular Disease

Adipose tissue plays essential roles in maintaining lipid and glucose homeostasis. To date several types of adipose tissue have been identified, namely white, brown, and beige, that reside in various specific anatomical locations throughout the body. The cellular composition, secretome, and location of these adipose depots define their function in health and metabolic disease. In obesity, adipose tissue becomes dysfunctional, promoting a pro-inflammatory, hyperlipidemic and insulin resistant environment that contributes to type 2 diabetes mellitus (T2DM). Concurrently, similar features that result from adipose tissue dysfunction also promote cardiovascular disease (CVD) by mechanisms that can be augmented by T2DM. The mechanisms by which dysfunctional adipose tissue simultaneously promote T2DM and CVD, focusing on adipose tissue depot-specific adipokines, inflammatory profiles, and metabolism, will be the focus of this review. The impact that various T2DM and CVD treatment strategies have on adipose tissue function and body weight also will be discussed.

Immunohistochemical analysis of adiponectin in atherosclerotic lesions of human aorta

BACKGROUND

Metabolic syndrome, a cluster of interrelated disorders including abdominal obesity, insulin resistance, dyslipidemia, and hypertension (HTN) plays an important role in development of atherosclerotic lesions in arterial wall. Dysregulation of adipose tissue hormones (adipokines) production is a possible link between abdominal obesity and other manifestations of metabolic syndrome. Adiponectin is a well-known adipokine which affects metabolism and inflammatory response. However, data on its role in atherogenesis are still controversial. The aim of this study is to investigate whether adiponectin is present in atherosclerotic lesions of human aorta.

METHODS

Thirty-five autopsy segments from abdominal, thoracic aortas, and aortic arch of four men (mean age: 57 years) were fixed and stained for lipids [Oil Red O (ORO)], cells [hematoxylin-eosin (H&E)], and adiponectin [indirect immunoperoxidase assay (IPA) method]. Samples of both stable and unstable plaques were selected for analysis. Human adipose tissue, THP-1 monocytes/macrophages, and human endothelial hybrid cell line (EA.hy926) were chosen for detection of adiponectin messenger ribonucleic acid (mRNA) using reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

Adiponectin accumulations were found inside endothelial cells covering both stable and unstable atherosclerotic plaques. Focal depositions of adiponectin were also found in fibrous caps of stable lesions and atheromatous core of both stable and unstable plaques and also in adventitia. RT-PCR revealed mRNA expression of adiponectin gene in adipose tissue, but not in mononuclears and endothelial cells.

CONCLUSION

Adiponectin is present in aortic plaques of humans, but is not synthesized in endothelial cells and mononuclears, at least in culture conditions. Detection of adiponectin in atherosclerotic lesions can serve as indirect evidence of possible participation of this adipokine in atherogenesis.

Exercise training prevents the perivascular adipose tissue-induced aortic dysfunction with metabolic syndrome

The aim of the study was to determine the effects of exercise training on improving the thoracic perivascular adipose tissue (tPVAT) phenotype (inflammation, oxidative stress, and proteasome function) in metabolic syndrome and its subsequent actions on aortic function.

Methods

Lean and obese (model of metabolic syndrome) Zucker rats (n=8/group) underwent 8-weeks of control conditions or treadmill exercise (70% of max speed, 1 h/day, 5 days/week). At the end of the intervention, the tPVAT was removed and conditioned media was made. The cleaned aorta was attached to a force transducer to assess endothelium-dependent and independent dilation in the presence or absence of tPVAT-conditioned media. tPVAT gene expression, inflammatory /oxidative phenotype, and proteasome function were assessed.

Results

The main findings were that Ex induced: (1) a beige-like, anti-inflammatory tPVAT phenotype; (2) a greater abundance of ^•NO in tPVAT; (3) a reduction in tPVAT oxidant production; and (4) an improved tPVAT proteasome function. Regarding aortic function, endothelium-dependent dilation was greater in exercised lean and obese groups vs. controls (p < 0.05). Lean control tPVAT improved aortic relaxation, whereas obese control tPVAT decreased aortic relaxation. In contrast, the obese Ex-tPVAT increased aortic dilation, whereas the lean Ex-tPVAT did not affect aortic dilation.

Conclusion

Overall, exercise had the most dramatic impact on the obese tPVAT reflecting a change towards an environment with less oxidant load, less inflammation and improved proteasome function. Such beneficial changes to the tPVAT micro-environment with exercise likely played a significant role in mediating the improvement in aortic function in metabolic syndrome following 8 weeks of exercise.

Caveolin-1 as a target in prevention and treatment of hypertrophic scarring

Reduced expression of caveolin-1 (Cav-1) is an important pathogenic factor in hypertrophic scarring (HTS). Such a reduction can be found in connection with the main known risk factors for HTS, including dark skin, female gender, young age, burn site and severity of the injury. The degree of overexpression of Cav-1 associated with different therapeutic options for HTS correlates with clinical improvements in HTS. This makes endo- or exogenous induction of Cav-1 not only an important therapeutic target for HTS, but also highlights its use as a preventive target to reduce or avoid HTS formation.

The role of NO-cGMP pathway inhibition in vascular endothelial-dependent smooth muscle relaxation disorder of AT1-AA positive rats: protective effects of adiponectin

Angiotensin II type 1 receptor autoantibodies (AT1-AA) cause endothelial-dependent smooth muscle relaxation disorder. It is well understood that impairment of the NO-cGMP signaling pathway is one of the mechanisms of endothelial-dependent smooth muscle relaxation disorder. However, it is still unclear whether AT1-AA induces endothelial-dependent smooth muscle relaxation disorder via the impairment of the NO-cGMP signaling pathway. In addition, adiponectin exerts vascular endothelial protection through the NO-cGMP signaling pathway. Therefore, the purpose of this investigation was to assess the mechanism of vascular endothelial-dependent smooth muscle relaxation disorder induced by AT1-AA and the role of adiponectin in attenuating this dysregulation. Serum endothelin-1 (ET-1), adiponectin and AT1-AA were detected by enzyme-linked immunosorbent assay. In preeclamptic patients, there was an increased level of AT1-AA, which was positively correlated with ET-1 and negatively correlated with adiponectin, as elevated levels of ET-1 suggested endothelial injury. AT1-AA-positive animal models were actively immunized with the second extracellular loop of the angiotensin II type 1 receptor (AT1R-ECII) for eight weeks. In thoracic aortas of AT1-AA positive rats, ET-1 was elevated, endothelium-dependent vasodilation was decreased. Paradoxically, as the upstream element of the NO-cGMP signaling pathway, NO production was not decreased but increased, and the ratio of p-VASP/VASP, an established biochemical endpoint of NO-cGMP signaling pathway, was reduced. Moreover, the levels of nitrotyrosine and gp91phox which indicate the presence of peroxynitrite (ONOO^-) and superoxide anion (O₂·^-) were increased. Pretreatment with the ONOO^- scavenger FeTMPyP or O₂·^-scavenger Tempol normalized vasorelaxation. Key enzymes responsible for NO synthesis were also assessed. iNOS protein expression was increased, but p-eNOS(Ser1177)/eNOS was reduced. Preincubation with the iNOS inhibitor 1400 W or eNOS agonist nebivolol restored vasorelaxation. Further experiments showed levels of p-AMPKα (Thr172)/AMPKα, which controls iNOS expression and eNOS activity, to have been reduced. Furthermore, levels of the upstream component of AMPK, adiponectin, was reduced in sera of AT1-AA positive rats and supplementation of adiponectin significantly decreased ET-1 contents, improved endothelial-dependent vasodilation, reduced NO production, elevated p-VASP/VASP, inhibited protein expression of nitrotyrosine and gp91phox, reduced iNOS overexpression, and increased eNOS phosphorylation at Ser1177 in the thoracic aorta of AT1-AA positive rats. These results established that impairment NO-cGMP pathway may aggravate the endothelial-dependent smooth muscle relaxation disorder in AT1-AA positive rats and adiponectin improved endothelial-dependent smooth muscle relaxation disorder by enhancing NO-cGMP pathway. This discovery may shed a novel light on clinical treatment of vascular diseases associated with AT1-AA.

Role of Adiponectin in Central Nervous System Disorders

Adiponectin, the most abundant plasma adipokine, plays an important role in the regulation of glucose and lipid metabolism. Adiponectin also possesses insulin-sensitizing, anti-inflammatory, angiogenic, and vasodilatory properties which may influence central nervous system (CNS) disorders. Although initially not thought to cross the blood-brain barrier, adiponectin enters the brain through peripheral circulation. In the brain, adiponectin signaling through its receptors, AdipoR1 and AdipoR2, directly influences important brain functions such as energy homeostasis, hippocampal neurogenesis, and synaptic plasticity. Overall, based on its central and peripheral actions, recent evidence indicates that adiponectin has neuroprotective, antiatherogenic, and antidepressant effects. However, these findings are not without controversy as human observational studies report differing correlations between plasma adiponectin levels and incidence of CNS disorders. Despite these controversies, adiponectin is gaining attention as a potential therapeutic target for diverse CNS disorders, such as stroke, Alzheimer's disease, anxiety, and depression. Evidence regarding the emerging role for adiponectin in these disorders is discussed in the current review.

Lack of direct effect of adiponectin on vascular smooth muscle cell BKCa channels or Ca2+ signaling in the regulation of small artery pressure-induced constriction

The aim of this study was to investigate mechanisms by which adiponectin influences vascular Ca²⁺ signaling, K⁺ channel activity and thus contractile tone of small arteries. Vasodilation to adiponectin was studied in mesenteric resistance arteries constricted with intraluminal pressure. Ca²⁺ signals were characterized using high speed confocal microscopy of intact arteries. Patch clamp investigated the effect of adiponectin on individual VSMC potassium (K⁺) channel currents. Adiponectin dilated arteries constricted with pressure‐induced tone by approximately 5% and the induced vasodilation was only transient. The dilation to adiponectin was reduced by pharmacological interruption of the Ca²⁺ spark/large conductance activated K⁺ (BK) channel pathway but from a physiological perspective, interpretation of the data was limited by the small effect. Neither Adiponectin nor the presence of intact perivascular adipose tissue (PVAT) influenced Ca²⁺ spark or Ca²⁺ wave frequency or characteristics. Studied using a perforated patch approach, Adiponectin marginally increased current through the VSMC BK channel but this effect was lost using the whole cell technique with dialysis of the cytoplasm. Adiponectin did not change the frequency or amplitude of Ca²⁺ spark‐induced transient outward currents (STOC). Overall, our study shows that Adiponectin induces only a small and transient dilation of pressure constricted mesenteric arteries. This vasodilatory effect is likely to be independent of Ca²⁺ sparks or direct BK channel activation.

Variations in ADIPOR1 But Not ADIPOR2 are Associated With Hypertriglyceridemia and Diabetes in an Admixed Latin American Population

BACKGROUND

Adiponectin is a hormone secreted by adipose tissue. It regulates glycolysis and lipolysis and is involved in the pathophysiology of diabetes and related disorders. Its activity is mainly mediated by the transmembrane receptors AdipoR1 and AdipoR2, which are encoded by ADIPOR1 (1q32.1) and ADIPOR2 (12p13.33) genes, respectively. In genetic association studies, single nucleotide polymorphisms (SNPs) in or near these genes have been associated with metabolic alterations. However, these relationships are still controversial.

AIM

The aim of this work was to analyze possible associations between ADIPOR1/2 and diabetes and other metabolic disorders.

METHODS

A genetic association study was carried out in an admixed Latin American population. A sample of 200 adults was analyzed. Clinical and serum-biochemical characteristics were measured to diagnose obesity, abdominal obesity, hypertension, hyperglycemia, hypertriglyceridemia, low HDLc, insulin resistance (HOMA-IR), and diabetes. Three SNPs were genotyped in ADIPOR1 (rs10494839, rs12733285, and rs2275737) and ADIPOR2 (rs11061937, rs11612383, and rs2286383). For the association analysis, an additive model was assessed through logistic regression. An admixture adjustment was performed using a Monte-Carlo-Markov-Chain method, assuming a three-hybrid substructure (k = 3).

RESULTS

Two SNPs in ADIPOR1 were associated with diabetes: rs10494839 (OR = 3.88, adjusted p < 0.03) and rs12733285 (OR = 4.72, adjusted p < 0.03). Additionally, rs10494839 was associated with hypertriglyceridemia (OR = 2.16, adjusted p < 0.01). None of the SNPs in ADIPOR2 were associated with metabolic disorders.

CONCLUSIONS

ADIPOR1 was consistently associated with diabetes and hypertriglyceridemia. This association was maintained even after adjusting for genetic stratification. There were no significant associations involving ADIPOR2.

The association of two polymorphisms in adiponectin-encoding gene with hypertension risk and the changes of circulating adiponectin and blood pressure: A meta-analysis

Objectives

This meta-analysis was prepared to synthesize published data on the association of two polymorphisms (T45G and G276T) in adiponectin-encoding gene (ADIPOQ) with hypertension risk and the changes of circulating adiponectin and blood pressure.

Methodology and Major Findings

Data were collected and corrected by two authors, and were managed with Stata software. In total, 12 articles were synthesized, including 12 studies (3358 cases and 5121 controls) for the association of two study polymorphisms with hypertension risk and 11 studies (3053 subjects) for the between-genotype changes of adiponectin and/or blood pressure. Based on all qualified studies, the risk prediction for hypertension was nonsignificant for both polymorphisms, with significant heterogeneity for G276T polymorphism (I² = 53.8%). Overall changes in adiponectin and blood pressure were also nonsignificant for T45G, while contrastingly 276GT genotype was associated with significantly higher levels of adiponectin (weighted mean difference [WMD] = 0.72 μg/mL, 95% confidence interval [CI]: 0.04 to 1.41, P = 0.038), systolic (WMD = 5.15 mm Hg, 95% CI: 0.98 to 9.32, P = 0.016) and diastolic (WMD = 3.45 mm Hg, 95% CI: 0.37 to 6.53, P = 0.028) blood pressure with evident heterogeneity (I² = 72.0%, 78.3% and 80.0%, respectively), and these associations were more obvious in hypertensive patients. Publication bias was a low probability event for overall comparisons.

Conclusions

Our findings suggested that in spite of the nonsignificant association between ADIPOQ T45G or G276T polymorphism and hypertension, the heterozygous mutation of G276T was observed to account for increased levels of circulating adiponectin and blood pressure, especially in hypertensive patients.

Adipokines: Potential Therapeutic Targets for Vascular Dysfunction in Type II Diabetes Mellitus and Obesity

Adipokines are bioactive molecules that regulate several physiological functions such as energy balance, insulin sensitization, appetite regulation, inflammatory response, and vascular homeostasis. They include proinflammatory cytokines such as adipocyte fatty acid binding protein (A-FABP) and anti-inflammatory cytokines such as adiponectin, as well as vasodilator and vasoconstrictor molecules. In obesity and type II diabetes mellitus (DM), insulin resistance causes impairment of the endocrine function of the perivascular adipose tissue, an imbalance in the secretion of vasoconstrictor and vasodilator molecules, and an increased production of reactive oxygen species. Recent studies have shown that targeting plasma levels of adipokines or the expression of their receptors can increase insulin sensitivity, improve vascular function, and reduce the risk of cardiovascular morbidity and mortality. Several reviews have discussed the potential of adipokines as therapeutic targets for type II DM and obesity; however, this review is the first to focus on their therapeutic potential for vascular dysfunction in type II DM and obesity.