Modulation of cardiovascular function by adipokines

The interplay between statins and adipokines. Is this another explanation of statins' 'pleiotropic' effects?

Statin therapy comprises an integral part of secondary and to a lesser extent of primary cardiovascular disease prevention. This is attributed not only to their lipid-lowering properties, but as well to a plethora of pleiotropic actions. Recently, the cytokines secreted by adipose tissue, the so-called adipokines, have been proved to play a critical role in various pathophysiological functions, among which inflammation and atherosclerosis development and vulnerability. The aim of this literature review was to summarize the effects of statins and the underlying mechanisms on the circulating levels of the most common adipokines regulating atherosclerosis process, as a part of their pleiotropic function. Up to now, robust evidence implicates a significant statin-induced reduction of pro-inflammatory adipokines IL-6, TNF-a and visfatin. Weak evidence from limited, small and mostly non-randomized studies suggest increased levels of anti-inflammatory adipokines apelin, vaspin and omentin-1 after statin therapy. In the rest of most known adipokines, statins have shown either controversial (adiponectin, retinol binding protein-4 and fetuin-A) or negligible effects (leptin and resistin) on their circulating levels. Therefore, statins may favourably alter the balance of inflammatory/anti-inflammatory adipokines, implicating a novel atheroprotective mechanism. However, the interplay between statins and adipokines is still not fully elucidated and its potential clinical relevance is warranted.

Emerging functions of adipokines in linking the development of obesity and cardiovascular diseases

Increasing evidence shows that obesity is the critical factor in shaping cardio-metabolic phenotypes. However, the pathogenic mechanisms remain incompletely clarified. According to the published reports, adipose tissue communicates with several diverse organs, such as heart, lungs, and kidneys through the secretion of various cytokines named adipokines. The adipocytes isolated from obese mice or humans are dysfunctional with aberrant production of pro-inflammatory adipokines, which subsequently induce both acute and chronic inflammatory reaction and facilitate the process of cardio-metabolic disorder complications. Furthermore, the microenvironment within adipose tissue under obese status also influence the secretion of adipokines. Recently, given that several important adipokines have been completely researched and causally involved in various diseases, we could make a conclusion that adipokines play an essential role in modulating the development of cardio-metabolic disorder diseases, whereas several novel adipokines continue to be explored and elucidated. In the present review, we summarized the current knowledge of the microenvironment of adipose tissue and the published mechanisms whereby adipocytes affects obesity and cardiovascular diseases. On the other hand, we also provide the evidence to elucidate the functions of adipokines in controlling and regulating the inflammatory reactions which contribute to obesity and cardiovascular disease.

The relationship between serum adiponectin levels, cardiometabolic indices and metabolic syndrome in schizophrenia

BACKGROUND

Adiponectin is a hormone secreted by adipose tissues that is thought to influence lipid and glucose metabolism, and the development of metabolic derangements, including metabolic syndrome (MetS), in schizophrenia. We aim to determine the serum adiponectin levels in Chinese patients with schizophrenia, and explore the relationship between adiponectin levels and metabolic parameters, including MetS and its components. We hypothesized that serum adiponectin levels are similar in schizophrenia patients and controls, but decreased amongst patients on atypical antipsychotics.

METHODS

81 patients and 81 controls were recruited. Anthropometric parameters and fasted blood samples for metabolic measurements were obtained. Serum adiponectin levels were measured using Bioplex assays.

RESULTS

There was no difference in median adiponectin levels between schizophrenia patients and controls. Those taking typical antipsychotics alone had lower median adiponectin levels than those on mixed typical and atypical antipsychotics. Serum adiponectin level, controlled for age, gender and body mass index, was positively correlated with high-density lipoprotein cholesterol, and negatively correlated with diastolic blood pressure, total cholesterol, low-density lipoprotein cholesterol, and triglyceride levels in schizophrenia patients. Patients with MetS had lower median adiponectin levels than those without MetS, and serum adiponectin levels decreased as the number of MetS components increased. After adjusting for variables thought to influence MetS, our logistic regression model did not reveal any significant association between adiponectin levels and MetS in schizophrenia patients.

CONCLUSION

Our findings highlight the need for more studies focusing on serum adiponectin level and its relationship with MetS in schizophrenia, particularly in those taking typical antipsychotics.

The prevalence of cardio-metabolic risk factors is differentially elevated in obesity-prone Osborne-Mendel and obesity-resistant S5B/Pl rats

AIMS

Individual susceptibility to develop obesity may impact the development of cardio-metabolic risk factors that lead to obesity-related comorbid conditions. Obesity-prone Osborne-Mendel (OM) rats expressed higher levels of visceral adipose inflammation than obesity-resistant, S5B/Pl (S5B) rats. However, the consumption of a high fat diet (HFD) differentially affected OM and S5B rats and induced an increase in visceral adipose inflammation in S5B rats. The current study examined the effects of HFD consumption on cardio-metabolic risk factors in OM and S5B rats.

MATERIALS & METHODS

Glucose regulation and circulating levels of lipids, adiponectin and C-reactive protein were assessed following 8 weeks of HFD or low fat diet (LFD) consumption. Left ventricle hypertrophy and mRNA expression of cardiovascular disease biomarkers were also quantified in OM and S5B rats.

KEY FINDINGS

Circulating levels of triglycerides were higher, while HDL cholesterol, adiponectin and glycemic control were lower in OM rats, compared to S5B rats. In the left ventricle, BNP and CTGF mRNA expression were higher in OM rats and IL-6, IL-1β, VEGF, and iNOS mRNA expression were higher in S5B rats.

SIGNIFICANCE

These findings support the hypothesis that cardio-metabolic risk factors are increased in obesity-prone individuals, which may increase the risk for the development of obesity-related comorbidities. In the current models, obesity-resistant S5B rats also exhibited cardiovascular risk factors supporting the importance of monitoring cardiovascular health in individuals characterized as obesity-resistant.

Adipokine expression and endothelial function in subclinical hypothyroidism rats

The purpose of our study was to observe adipokine expression and endothelial function in subclinical hypothyroidism (sHT) rats and to determine whether levothyroxine (LT₄) treatment affects these changes. Sixty-five male Wistar rats were randomly divided into five groups: the control group; sHT A, B and C groups and the sHT + T₄ group. The sHT rats were induced by methimazole (MMI) and the sHT + T₄ rats were administered LT₄ treatment after 8 weeks of MMI administration. Thyroid function and lipid levels were measured using radioimmunoassays and enzymatic colorimetric methods, respectively. Serum adiponectin (APN), chemerin, TNF-α, endothelin (ET-1) and nitric oxide (NO) levels were measured using ELISA kits and a nitric-reductive assay. The expression of APN, chemerin and TNF-α in visceral adipose tissue (VAT) was measured in experimental rats using RT-PCR and Western blotting. Hematoxylin-eosin (HE) staining was used to observe changes in adipose tissue. The sHT rats had significantly higher levels of thyroid-stimulating hormone (TSH), TNF-α, chemerin, ET-1, total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) and lower levels of APN and NO than those in control and sHT + T₄ rats. Based on Pearson correlation analysis, the levels of chemerin, TNF-α, ET-1, LDL-C, TC and triglyceride (TG) were positively correlated with TSH, but APN and NO levels were negatively correlated with TSH. These findings demonstrated that high TSH levels contribute to the changes of adipokines and endothelial dysfunction in sHT, but LT₄ treatment ameliorates those changes.

Rosuvastatin Improves Vaspin Serum Levels in Obese Patients with Acute Coronary Syndrome

Adipose tissue-derived serine protease inhibitor (vaspin), which has endocrine and local roles in atherosclerosis growth, is also synthesized by adipose tissue; it was found that vaspin was negatively correlated with blood pressure in obese patients, while vaspin levels were decreased in endothelial dysfunction. The aim of the present study was to determine rosuvastatin modulation effects on serum vaspin levels in acute coronary syndrome (ACS) with class I obesity. A total number of seventy patients with acute coronary syndrome previously and currently treated with rosuvastatin was compared to 40 patients with IHD not treated by rosuvastatin as a control. Vaspin serum levels were higher in rosuvastatin-treated patients with acute coronary syndrome compared to the patients with acute coronary syndrome not treated by rosuvastatin, p < 0.01. Additionally, in the rosuvastatin-treated group, patients with STEMI showed higher vaspin serum levels compared to NSTEMI p < 0.01. Conclusion: Rosuvastatin significantly increases vaspin serum levels in acute coronary syndrome.

Relationship Between Adiponectin and apoB in Individuals With Diabetes in the Atlantic PATH Cohort

Context

The increasing prevalence of obesity and diabetes greatly influences the risk for cardiovascular (CV) comorbidities and affects the quality of life of many people. However, the relationship among diabetes, obesity, and cardiovascular risk is complex and requires further investigation to understand the biological milieu connecting these conditions.

Objective

The aim of the current study was to explore the relationship between biological markers of adipose tissue function (adiponectin) and CV risk (apolipoprotein B) in body mass index (BMI)-matched participants with and without diabetes.

Design

Nested case-control study.

Setting

The Atlantic Partnership for Tomorrow's Health (PATH) cohort represents four Atlantic Canadian provinces: Newfoundland and Labrador, New Brunswick; Nova Scotia; and Prince Edward Island.

Participants

The study population (n = 480) was aged 35 to 69 years, 240 with diabetes and 240 without diabetes.

Main Outcome Measures

Groups with and without diabetes were matched for sex and BMI. Both measured and self-reported data were used to examine disease status, adiposity, and lifestyle factors. Immunoassays were used to measure plasma markers.

Results

In these participants, plasma adiponectin levels were lower among those with diabetes than those without diabetes; these results were sex-specific, with a strong relationship seen in women. In contrast, in participants matched for sex and adiposity, plasma apoB levels were similar between participants with and those without diabetes.

Conclusion

Measures of adiposity were higher in participants with diabetes. However, when matched for adiposity, the adipokine adiponectin exhibited a strong inverse association with diabetes.

Nesfatin-1: a new energy-regulating peptide with pleiotropic functions. Implications at cardiovascular level

Nesfatin-1 is a new energy-regulating peptide widely expressed at both central and peripheral tissues with pleiotropic effects. In the last years, the study of nesfatin-1 actions and its possible implication in the development of different diseases has created a great interest among the scientific community. In this review, we will summarize nesfatin-1 main functions, focusing on its cardiovascular implications.

Adipokines Vaspin and Visfatin in Obese Children

BACKGROUND

Adipokines provides new insights about the physiology, pathology and treatment of obesity.

AIM

We investigated the association between serum vaspin and serum visfatin concentrations with obesity in Egyptian children.

MATERIAL AND METHODS

Twenty two obese children with body mass index (BMI) above 95th percentile; 11 males and 11 females were included in this study. Their mean age was 9.18 ± 2.8 years. After general clinical examination, fasting blood glucose, triglycerides, total cholesterol and high density lipoprotein cholesterol were measured in cases and controls (n=11). Fasting insulin, vaspin and visfatin were detected using ELIZA. Insulin resistance was estimated by Homeostasis model assessment method (HOMA-IR).

RESULTS

Blood pressure, in both systolic and diastolic measurements was elevated significantly in obese children. Significant elevation of serum insulin and insulin resistance (HOMA/IR) were observed in obese children too. Vaspin and visfatin showed significant elevation in obese children than controls. Significant positive correlations were detected between visfatin and BMI, waist circumference, hip circumference and HOMA/IR. We found that Vaspin and visfatin are higher in obese children.

CONCLUSION

Visfatin but not vaspin correlates positively with waist circumference and HOMA/IR in obese children.

Increased vaspin levels are associated with beneficial metabolic outcome pre- and post-bariatric surgery

Purpose

Vaspin (visceral-adipose-tissue-derived-serine-protease-inhibitor) is a recently identified adipokine with putative insulin-sensitizing properties. Plasma vaspin responses to surgery-induced weight loss are sparse and contradictory.

Design and Participants

We evaluated changes in vaspin levels and relationship to post-operative outcomes in men (n = 22) and women (n = 55) undergoing biliopancreatic-diversion/duodenal-switch bariatric surgery. Body composition and plasma parameters were measured at baseline, acutely (1 and 5 days) and medium-term (6 and 12 months) post-surgery.

Results

Fasting preoperative vaspin concentrations were comparable in men vs women. The distribution was biphasic (both men and women) with a nadir of 2.5 ng/ml. Subjects were divided into high (≥2.5 ng/mL, HI-group) and low (<2.5 ng/mL, LO-group) vaspin level. Both groups had comparable sex distribution, age and BMI, but the HI-vaspin group had lower insulin, HOMA, and triglyceride and higher HDL-cholesterol, acylation stimulating protein (ASP) and IL-6 levels (all p<0.05). Post-operatively, both groups decreased BMI comparably over 12 months; the HI-vaspin group maintained high vaspin levels, while the LO-vaspin group gradually increased their levels with weight loss over 12 months. The HI-vaspin group maintained a better glucose, insulin, HOMA, fructosamine, HDL-cholesterol, and triglyceride profile throughout. The HI-vaspin group also had higher gamma-glutamyltransferase and ASP profiles. Finally, baseline vaspin level inversely correlated significantly with baseline and 12-month insulin, HOMA, triglyceride and positively correlated with HDL and ASP. Twelve-month vaspin also correlated similarly, including an inverse correlation with BMI.

Conclusion

Globally, this study supports the concept of vaspin as a beneficial adipokine in obesity, which may potentially lead to possible therapeutic targets.

Mechanisms by Which Pleiotropic Amphiphilic n-3 PUFA Reduce Colon Cancer Risk

Colorectal cancer is one of the major causes of cancer-related mortality in both men and women worldwide. Genetic susceptibility and diet are primary determinants of cancer risk and tumor behavior. Experimental, epidemiological, and clinical data substantiate the beneficial role of n-3 polyunsaturated fatty acids (PUFA) in preventing chronic inflammation and colon cancer. From a mechanistic perspective, n-3 PUFA are pleiotropic and multifaceted with respect to their molecular mechanisms of action. For example, this class of dietary lipid uniquely alters membrane structure/ cytoskeletal function, impacting membrane receptor function and downstream signaling cascades, including gene expression profiles and cell phenotype. In addition, n-3 PUFA can synergize with other potential anti-tumor agents, such as fermentable fiber and curcumin. With the rising prevalence of diet-induced obesity, there is also an urgent need to elucidate the link between chronic inflammation in adipose tissue and colon cancer risk in obesity. In this review, we will summarize recent developments linking n-3 PUFA intake, membrane alterations, epigenetic modulation, and effects on obesity-associated colon cancer risk.

The response of circulating leptin levels to exercise stress testing in subjects diagnosed with metabolic syndrome

Aim. To assess the plasma leptin responses after exercise stress testing in patients with metabolic syndrome (MS). Material and Methods. We investigated 67 patients with MS, with mean age of 55 ± 7 years. They underwent exercise stress testing on cycloergometer. The lot was divided into three groups: group 1-10 patients with a true positive test, group 2-18 patients with a true negative test, and group 3-39 patients with a false negative test. Leptin levels were measured using the ELISA method. Results. Leptin levels decreased after effort in patients with MS (9.42 ± 11.08 ng/mL before and 8.18 ± 11.5 ng/mL after the exercise stress test, P = 0.0005, r = 0.874). In groups 1 (8.98 ± 9.09 at rest versus 5.98 ± 8.73 ng/mL after the exercise test, P = 0.002) and 3 (8.6 ± 10.53 at rest versus 6.91 ± 9.07 ng/mL, P = 0.0005), lower leptin levels were recorded immediately after exercise testing. Leptin levels were not significantly lower in group 2 before effort (9.49 ± 11.36 ng/ml) and after (9.46 ± 13.81 ng/mL). We found no correlation between leptinemia and exercise stress testing parameters, regardless of group. Conclusion. Our research showed that short-term exercise lowers leptin levels in coronary patients, without a relationship between its parameters and leptin values.

Obesity-associated oxidative stress: strategies finalized to improve redox state

Obesity represents a major risk factor for a plethora of severe diseases, including diabetes, cardiovascular disease, non-alcoholic fatty liver disease, and cancer. It is often accompanied by an increased risk of mortality and, in the case of non-fatal health problems, the quality of life is impaired because of associated conditions, including sleep apnea, respiratory problems, osteoarthritis, and infertility. Recent evidence suggests that oxidative stress may be the mechanistic link between obesity and related complications. In obese patients, antioxidant defenses are lower than normal weight counterparts and their levels inversely correlate with central adiposity; obesity is also characterized by enhanced levels of reactive oxygen or nitrogen species. Inadequacy of antioxidant defenses probably relies on different factors: obese individuals may have a lower intake of antioxidant- and phytochemical-rich foods, such as fruits, vegetables, and legumes; otherwise, consumption of antioxidant nutrients is normal, but obese individuals may have an increased utilization of these molecules, likewise to that reported in diabetic patients and smokers. Also inadequate physical activity may account for a decreased antioxidant state. In this review, we describe current concepts in the meaning of obesity as a state of chronic oxidative stress and the potential interventions to improve redox balance.