Hypertension and the Metabolic Syndrome

Blood pressure response to extended-release naltrexone in heroin and prescription opioid users and its implications for cardiovascular morbidity

BACKGROUND

Consuming opioid agonists is a risk factor for cardiovascular disease particularly in intravenous heroin users. The monthly injectable extended-release opioid antagonist, naltrexone (XR-NTX) is an effective treatment for opioid use disorder. The impact of opioid receptor blockade through XR-NTX on blood pressure, a critical risk factor for cardiovascular morbidity, has not yet been characterized.

METHODS

The study evaluated the change in blood pressure during XR-NTX treatment among 14 patients who predominately used intravenous heroin and 24 patients who used prescription oral opioids, all with opioid use disorder. Blood pressure was measured in each patient immediately before the first XR-NTX injection and ∼two weeks after the first injection. The change in diastolic and systolic pressure was compared between the heroin users and the prescription opioids users using analysis of variance.

RESULTS

XR-NTX treatment was associated with significant decreases in diastolic blood pressure in the heroin group, but not in the prescription opioids group. Systolic blood pressure values in the heroin users showed a decline at trend level only.

CONCLUSIONS

Further research is warranted to replicate our findings and to determine whether XR-NTX effect is relatively specific to blood pressure or generalizes to other components of metabolic syndrome. Distinguishing between heroin and prescription opioid users could shed light on the unique clinical and pharmacological profiles of opioid drugs, particularly regarding their cardiovascular safety. This information can be useful in developing personalized therapeutic strategies based on the route of opioid administration.

Machine Learning Approach for Metabolic Syndrome Diagnosis Using Explainable Data-Augmentation-Based Classification

Metabolic syndrome (MetS) is a cluster of risk factors including hypertension, hyperglycemia, dyslipidemia, and abdominal obesity. Metabolism-related risk factors include diabetes and heart disease. MetS is also linked to numerous cancers and chronic kidney disease. All of these variables raise medical costs. Developing a prediction model that can quickly identify persons at high risk of MetS and offer them a treatment plan is crucial. Early prediction of metabolic syndrome will highly impact the quality of life of patients as it gives them a chance for making a change to the bad habit and preventing a serious illness in the future. In this paper, we aimed to assess the performance of various algorithms of machine learning in order to decrease the cost of predictive diagnoses of metabolic syndrome. We employed ten machine learning algorithms along with different metaheuristics for feature selection. Moreover, we examined the effects of data augmentation in the prediction accuracy. The statistics show that the augmentation of data after applying feature selection on the data highly improves the performance of the classifiers.

Effects of glycine on metabolic syndrome components: a review

PURPOSE

Glycine is the simplest and major amino acid in humans. It is mainly generated in the liver and kidney and is used to produce collagen, creatine, glucose and purine. It is also involved in immune function, anti-inflammatory processes and anti-oxidation reactions. Here, we reviewed the current evidence supporting the role of glycine in the development and treatment of metabolic syndrome components.

METHODS

We searched Scopus, PubMed and EMBASE databases for papers concerning glycine and metabolic syndrome.

RESULTS

Available evidence shows that the amount of glycine synthesized in vivo is insufficient to meet metabolic demands in these species. Plasma glycine levels are lower in subjects with metabolic syndrome than in healthy individuals. Interventions such as lifestyle modification, exercise, weight loss, or drugs that improve manifestations of metabolic syndrome remarkably increase circulating glycine concentrations.

CONCLUSION

Glycine supplementation improves various components of metabolic syndrome including diabetes, obesity, hyperlipidemia and hypertension. In the future, the use of glycine may have a significant clinical impact on the treatment of patients with metabolic syndrome.

Targeting Features of the Metabolic Syndrome Through Sympatholytic Effects of SGLT2 Inhibition

PURPOSE OF REVIEW

The moderate glucose-lowering effect of sodium glucose co-transporter 2 (SGLT2) inhibitors is unlikely to explain SGLT2 inhibitor-mediated beneficial outcomes, and unravelling the underlying mechanisms is a high priority in the research community. Given the dominant pathophysiologic role of the sympathetic nervous system activation in conditions such as hypertension and perturbed glucose homeostasis, it is pertinent to postulate that SGLT2 inhibitors may exert their beneficial effects at least in part via sympathetic inhibition.

RECENT FINDINGS

SGLT2 inhibitors have shown enormous potential to improve cardiovascular outcomes in patients with type 2 diabetes, and their therapeutic potential is currently being investigated in a range of associated comorbidities such as heart failure and chronic kidney disease. Indeed, recent experimental data in relevant animal models highlight a bidirectional interaction between sympathetic nervous system activation and SGLT2 expression, and this facilitates several of the features associated with SGLT2 inhibition observed in clinical trials including improved glucose metabolism, weight loss, increased diuresis, and lowering of blood pressure. Currently available data highlight the various levels of interaction between the sympathetic nervous system and SGLT2 expression and explores the potential for SGLT2 inhibition as a therapeutic strategy in conditions commonly characterised by sympathetic activation.

Current Status and Future Perspectives on Therapeutic Potential of Apigenin: Focus on Metabolic-Syndrome-Dependent Organ Dysfunction

Metabolic syndrome and its associated disorders such as obesity, insulin resistance, atherosclerosis and type 2 diabetes mellitus are globally prevalent. Different molecules showing therapeutic potential are currently available for the management of metabolic syndrome, although their efficacy has often been compromised by their poor bioavailability and side effects. Studies have been carried out on medicinal plant extracts for the treatment and prevention of metabolic syndrome. In this regard, isolated pure compounds have shown promising efficacy for the management of metabolic syndrome, both in preclinical and clinical settings. Apigenin, a natural bioactive flavonoid widely present in medicinal plants, functional foods, vegetables and fruits, exerts protective effects in models of neurological disorders and cardiovascular diseases and most of these effects are attributed to its antioxidant action. Various preclinical and clinical studies carried out so far show a protective effect of apigenin against metabolic syndrome. Herein, we provide a comprehensive review on both in vitro and in vivo evidence related to the promising antioxidant role of apigenin in cardioprotection, neuroprotection and renoprotection, and to its beneficial action in metabolic-syndrome-dependent organ dysfunction. We also provide evidence on the potential of apigenin in the prevention and/or treatment of metabolic syndrome, analysing the potential and limitation of its therapeutic use.

Catestatin peptide of chromogranin A as a potential new target for several risk factors management in the course of metabolic syndrome

Obesity, lipodystrophy, diabetes, and hypertension collectively constitute the main features of Metabolic Syndrome (MetS), together with insulin resistance (IR), which is considered as a defining element. MetS generally leads to the development of cardiovascular disease (CVD), which is a determinant cause of mortality and morbidity in humans and animals. Therefore, it is essential to implement and put in place adequate management strategies for the treatment of this disease. Catestatin is a bioactive peptide with 21 amino acids, which is derived through cleaving of the prohormone chromogranin A (CHGA/CgA) that is co-released with catecholamines from secretory vesicles and, which is responsible for hepatic/plasma lipids and insulin levels regulation, improves insulin sensitivity, reduces hypertension and attenuates obesity in murine models. In humans, there were few published studies, which showed that low levels of catestatin are significant risk factors for hypertension in adult patients. These accumulating evidence documents clearly that catestatin peptide (CST) is linked to inflammatory and metabolic syndrome diseases and can be a novel regulator of insulin and lipid levels, blood pressure, and cardiac function. The goal of this review is to provide an overview of the CST effects in metabolic syndrome given its role in metabolic regulation and thus, provide new insights into the use of CST as a diagnostic marker and therapeutic target.

Hearing Loss Characteristics of Workers with Hypertension Exposed to Occupational Noise: A Cross-Sectional Study of 270,033 Participants

Objectives

This study investigated the hearing loss characteristics among occupational noise exposure workers with hypertension and the link between hypertension and hearing loss when exposed to occupational noise.

Methods

A total of 267,766 occupational noise-exposed workers were enrolled, including 29,868 workers with hypertension and 240,165 without hypertension. Hypertension was diagnosed according to WHO criteria. Hypertension was classified into four grades based on blood pressure. Assessment of hearing was performed through measurement of an unadulterated tone threshold at different frequencies, which ranged between 250 and 8,000 Hz.

Results

A substantial link was observed to exist between hypertension and the increment in the hearing limit. The increase in the hearing threshold was substantially higher among those having grade 2 hypertension.

Conclusion

The current investigation suggested patients with hypertension exhibit a substantial rise in hearing loss in comparison with patients without hypertension. The rise in hearing loss was significant in patients with grade 2 hypertension. Efficient and practicable measures are required to decrease the hearing loss in workers with hypertension and work-related noise exposure.

Effects of metformin on blood pressure in nondiabetic patients: a meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the effects of metformin on systolic blood pressure (SBP) and diastolic blood pressure (DBP) in nondiabetic patients.

METHODS

In this meta-analysis, we systematically searched PubMed, Embase, and the Cochrane Library through March 2016, and randomized controlled trials assessing the effects of metformin treatment compared with placebo were included. Random-effects models were used to estimate pooled mean differences in SBP and DBP.

RESULTS

Twenty-eight studies from 26 articles consisting of 4113 participants were included. Pooled results showed that metformin had a significant effect on SBP (mean difference -1.98 mmHg; 95% confidence interval -3.61, -0.35; P = 0.02), but not on DBP (mean difference -0.67 mmHg; 95% confidence interval -1.74, 0.41; P = 0.22). In subgroup analysis, we found that the effect of metformin on SBP was significant in patients with impaired glucose tolerance or obesity (BMI ≥30 kg/m), with a mean reduction of 5.03 and 3.00 mmHg, respectively. Significant heterogeneity was found for both SBP (I = 60.0%) and DBP (I = 45.4%). A sensitivity analysis indicated that the pooled effects of metformin on SBP and DBP were robust to systematically dropping each trial. Furthermore, no evidence of significant publication bias from funnel plots or Egger's tests (P = 0.51 and 0.21 for SBP and DBP, respectively) was found.

CONCLUSION

This meta-analysis suggested that metformin could effectively lower SBP in nondiabetic patients, especially in those with impaired glucose tolerance or obesity.

The Effect of Anthocyanin-Rich Purple Vegetable Diets on Metabolic Syndrome in Obese Zucker Rats

Consumption of highly colored fruits and vegetables rich in anthocyanins has been associated with numerous health benefits. Purple carrots (PC) and purple potatoes (PP) have higher anthocyanin concentrations and higher biological activities compared with less pigmented cultivars. We hypothesized that substitution of the majority of carbohydrate in a high fat diet with PP or PC, for 8 weeks, would improve insulin resistance and hypertension, major components of metabolic syndrome, compared with orange carrots (OC), white potatoes (WP) or a control, high fat, sucrose-rich diet (HFD) in obese Zucker rats. After 8 weeks of feeding, intraperitoneal glucose tolerance test, intraperitoneal insulin tolerance test (ipITT), and invasive hemodynamic tests were performed. The PP group had better glucose tolerance compared with the WP and the HFD groups and higher insulin sensitivity as measured by the ipITT and homeostatic model assessment of insulin resistance (P = .018) compared with the HFD without having any effect on blood pressure. The PC reduced left ventricular pressure compared with both the HFD (P = .01) and the OC (P = .049) groups and reduced systolic and diastolic blood pressures compared with the HFD group (P = .01 and <.0001, respectively) without having any effect on glucose homeostasis. The PC animals consumed more and were more obese than other groups, possibly obscuring any benefit of this vegetable on glucose tolerance. The bioactives in the vegetables responsible for blood pressure and glucose homeostasis could be different, and their effects could be independent of each other. The specific bioactives of each vegetable and their molecular targets remain to be identified. Nonetheless, incorporation of purple vegetables in functional food products may provide metabolic/cardiovascular benefits in the background of a high-fat diet that promotes obesity.

Leptin is an independent marker of metabolic syndrome in elderly adults with type 2 diabetes

OBJECTIVE

It is well established that patients with metabolic syndrome (MetS) demonstrate elevated levels of serum leptin. The aim of this study is to identify fasting serum leptin as an independent marker of MetS in geriatric diabetic patients.

MATERIALS AND METHODS

Sixty-four patients over 65 years old with type 2 diabetic mellitus (T2DM) were assessed for MetS based on the diagnostic criteria of the International Diabetes Federation. Fasting blood samples including serum leptin concentrations were obtained from the participants. Leptin levels were determined using a commercial enzyme immunoassay.

RESULTS

Forty-five (70.3%) of the 64 geriatric T2DM patients enrolled in this study were found to have MetS. This group of participants compared with those in the non-MetS group had higher serum levels of leptin (P = 0.004), triglycerides (P = 0.005), fasting glucose (P = 0.049), glycated hemoglobin (P = 0.016), white blood cells (P = 0.003), C-reactive protein (CRP, P = 0.028), insulin (P < 0.001), higher homeostatic model assessment insulin resistance values (HOMA1-IR and HOMA2-IR, both P < 0.001), a higher body weight (P = 0.024), body mass index (P < 0.001), body fat mass (P < 0.001), waist circumference (P < 0.001), systolic blood pressure (BP) (P < 0.001), diastolic BP (P < 0.001), percentage of women (P = 0.011), prevalence of hypertension (P = 0.042), and a lower level of serum high-density lipoprotein cholesterol (P = 0.001). Univariate linear analysis of the clinical variables associated with the fasting serum leptin level revealed that height (P = 0.020) had a negative correlation, while body fat mass (P < 0.001) and logarithmically transformed CRP (log-CRP, P < 0.001) had positive correlations with serum leptin levels. Multivariate forward step-wise linear regression analysis of the variables significantly associated with fasting serum leptin levels showed that body fat mass (P < 0.001) and log-CRP (P = 0.001) were independent predictors of these values.

CONCLUSION

Serum leptin is positively correlated with MetS. It serves as an independent marker of MetS in elderly patients with T2DM.

Roles of the interorgan neuronal network in the development of metabolic syndrome

Metabolic processes in different tissues and remote organs are under coordinated systemic regulation, allowing adaptation to a variety of external circumstances. Neuronal signals as well as humoral factors, such as nutrients, growth factors, and hormones, have attracted increasing attention for their roles in this interorgan metabolic network, responsible for the maintenance of metabolic homeostasis at the whole-body level. These interorgan communications within an organism are considered to be diverse and, in fact, we identified previously unknown neuronal relay systems originating in the liver which modulate energy, glucose, and lipid metabolism. Furthermore, when nutrient overload is prolonged, these neuronal mechanisms, which function as an endogenous defense system against obesity development, contribute to the pathophysiological states of metabolic syndrome characterized by obesity-associated features. Therefore, these interorgan neuronal systems are considered to be possible molecular targets for treating metabolic syndrome. We herein review the precise mechanisms underlying the functions of the mammalian interorgan neuronal network, especially the pathways from the liver to several other organs, focusing on their significance and roles in the development of metabolic syndrome.

The impacts of obesity on the cardiovascular and renal systems: cascade of events and therapeutic approaches

There is a neglected epidemic of both obesity and metabolic syndrome in industrialized and unindustrialized countries all over the globe. Both conditions are associated with a high incidence of other serious pathologies, such as cardiovascular and renal diseases. In this article, we review the potential underlying mechanisms by which obesity and metabolic syndrome promote hypertension, including changes in cardiovascular-renal physiology induced by leptin, the sympathetic nervous system, the renin-angiotensin-aldosterone system, insulin resistance, free fatty acids, natriuretic peptides, and proinflammatory cytokines. We also discuss the potential underlying mechanisms by which obesity promotes other cardiovascular and renal conditions, as well as available nonpharmacologic and pharmacologic approaches for treating obesity-induced hypertension. The findings presented herein suggest that adipocytes may be a key regulator of cardiovascular and renal function.

Impact of Adiposity on Incident Hypertension Is Modified by Insulin Resistance in Adults: Longitudinal Observation From the Bogalusa Heart Study

Adiposity and insulin resistance are closely associated with hypertension. This study aims to investigate whether the association between adiposity and hypertension is modified by insulin resistance. The cohort consisted of 1624 middle-aged normotensive black and white adults aged 18 to 43 years at baseline who followed for 16 years on average. Overweight/obesity at baseline was defined as body mass index (BMI) ≥25, and insulin resistance was measured using homeostasis model assessment of insulin resistance. Prevalence of incident hypertension was compared between the insulin-sensitive adiposity and insulin-resistant adiposity groups. The prevalence of incident hypertension was higher in the insulin-resistant adiposity than in the insulin-sensitive adiposity group (32.1% versus 22.1%, P<0.001). In multivariable logistic analyses, adjusted for baseline age, race, sex, follow-up years, and smoking, baseline insulin-resistant obesity was associated with incident hypertension (odds ratio, 1.9; P=0.008). Odds ratios did not differ between blacks and whites (P=0.238). Of note, the odds ratios of BMI associated with hypertension significantly increased with increasing quartiles of baseline homeostasis model assessment (odds ratio, 1.3, 1.1, 1.5, and 2.5 in quartiles I, II, III, and IV, respectively; P=0.006 for trend). Slopes of increasing follow-up blood pressure with baseline BMI, measured as regression coefficients (β), were significantly greater in insulin-resistant than in insulin-sensitive individuals (β=0.74 versus β=0.35 for systolic blood pressure, P=0.004 for difference; β=0.51 versus β=0.23 for diastolic blood pressure, P=0.001 for difference). These findings suggest that insulin resistance has a synergistic effect on the obesity-hypertension association in young adults, indicating that the role of adiposity in the development of hypertension is modified by insulin resistance.

A comprehensive review on metabolic syndrome

Metabolic syndrome is defined by a constellation of interconnected physiological, biochemical, clinical, and metabolic factors that directly increases the risk of cardiovascular disease, type 2 diabetes mellitus, and all cause mortality. Insulin resistance, visceral adiposity, atherogenic dyslipidemia, endothelial dysfunction, genetic susceptibility, elevated blood pressure, hypercoagulable state, and chronic stress are the several factors which constitute the syndrome. Chronic inflammation is known to be associated with visceral obesity and insulin resistance which is characterized by production of abnormal adipocytokines such as tumor necrosis factor α , interleukin-1 (IL-1), IL-6, leptin, and adiponectin. The interaction between components of the clinical phenotype of the syndrome with its biological phenotype (insulin resistance, dyslipidemia, etc.) contributes to the development of a proinflammatory state and further a chronic, subclinical vascular inflammation which modulates and results in atherosclerotic processes. Lifestyle modification remains the initial intervention of choice for such population. Modern lifestyle modification therapy combines specific recommendations on diet and exercise with behavioural strategies. Pharmacological treatment should be considered for those whose risk factors are not adequately reduced with lifestyle changes. This review provides summary of literature related to the syndrome's definition, epidemiology, underlying pathogenesis, and treatment approaches of each of the risk factors comprising metabolic syndrome.

Factors associated with the prevalence of hypertension in the southeastern United States: insights from 69,211 blacks and whites in the Southern Community Cohort Study

BACKGROUND

Lifestyle and socioeconomic status have been implicated in the prevalence of hypertension; thus, we evaluated factors associated with hypertension in a cohort of blacks and whites with similar socioeconomic status characteristics.

METHODS AND RESULTS

We evaluated the prevalence and factors associated with self-reported hypertension (SR-HTN) and ascertained hypertension (A-HTN) among 69,211 participants in the Southern Community Cohort Study. Multivariable logistic regression models were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for factors associated with hypertension. The prevalence of SR-HTN was 57% overall. Body mass index was associated with SR-HTN in all race-sex groups, with the OR rising to 4.03 (95% CI, 3.74-4.33) for morbidly obese participants (body mass index, >40 kg/m(2)). Blacks were more likely to have SR-HTN than whites (OR, 1.84; 95% CI, 1.75-1.93), and the association with black race was more pronounced among women (OR, 2.08; 95% CI, 1.95-2.21) than men (OR, 1.47; 95% CI, 1.36-1.60). Similar findings were noted in the analysis of A-HTN. Among those with SR-HTN and A-HTN who reported use of an antihypertensive agent, 94% were on at least one of the major classes of antihypertensive agents, but only 44% were on ≥2 classes and only 29% were on a diuretic. The odds of both uncontrolled hypertension (SR-HTN and A-HTN) and unreported hypertension (no SR-HTN and A-HTN) were twice as high among blacks as whites (OR, 2.13; 95% CI, 1.68-2.69; and OR, 1.99; 95% CI, 1.59-2.48, respectively).

CONCLUSIONS

Despite socioeconomic status similarities, we observed suboptimal use of antihypertensives in this cohort and racial differences in the prevalence of uncontrolled and unreported hypertension, which merit further investigation.

Reevaluation of the prevalence of metabolic syndrome in an urban area of Turkey

OBJECTIVE

Our aim was to reveal a change in the prevalence of metabolic syndrome (MS) in the province of Konya in five years.

METHODS

We studied 202 obese children and adolescents (body mass index >95th percentile) aged between 7 and 18 years. The diagnosis of impaired glucose tolerance, type 2 diabetes mellitus (T2DM), and MS were defined according to the modified World Health Organization criteria adapted for children.

RESULTS

MS was found in 56.4 % with a significantly higher rate among adolescents aged 12-18 years (63.2%) than among prepubertal children aged 7-11 years (47%) (p=0.01). The prevalence figures for insulin resistance, glucose intolerance, and T2DM were 60, 8, and 2% among prepubertal children and 81.8, 12.8, and 0% among adolescents, respectively. The prevalence of fasting hyperinsulinemia in adolescents was significantly higher than in prepubertal children (p<0.001). Hypertension was significantly more common in adolescents (42.8%) than in prepubertal children (32.9%) (p=0.04).

CONCLUSIONS

We found that the incidence of MS in the city center of Konya approximately doubled in the last five years with increased rates of morbidity and abnormal lipid profiles.

Prevention of cardiovascular complications of the metabolic syndrome: focus on pharmacotherapy

The metabolic syndrome increases the risk of atherothrombotic cardiovascular disease (CVD) and diabetes. In turn, diabetes promotes the development of atheroma and is regarded as a coronary heart disease risk equivalent. A multifactorial therapeutic strategy is advocated for patients with the metabolic syndrome to improve cardiovascular risk factor profiles and to reduce the chances of developing type 2 diabetes. Individual components of the syndrome must be addressed using safe, efficacious, and cost-effective measures. There is general agreement that lifestyle modifications, including control of body weight, avoidance of central adiposity, adoption of an antiatherogenic diet, and regular physical activity, are crucial. However, as the magnitude of the individual components of the metabolic syndrome increases with time, lifestyle measures are often insufficient. An individual with metabolic syndrome will often require drug treatment for hyperglycemia, atherogenic dyslipidemia, and high blood pressure, together with antiplatelet therapy. Reducing the need for polypharmacy is an increasingly important consideration for clinicians and the pharmaceutical industry; to date, no single therapy has emerged that targets the root cause(s) of the syndrome. HMG-CoA reductase inhibitors are important agents that reduce CVD morbidity and mortality, in people with impaired fasting glucose or metabolic syndrome. Selective cannabinoid receptor antagonists appear promising because they improve or attenuate several key defects of the syndrome. Thiazolidinediones and metformin are presently licensed for treatment of type 2 diabetes but may prove to have a broader role in future. Novel insulin-sensitizing drugs are under investigation. Drugs that act to prevent or reverse endothelial dysfunction may be of particular utility in preventing cardiovascular disease, especially if initiated before tissue damage has become irreversible. Insulin therapy, which has antiinflammatory and endothelial protective properties, has been shown to reduce morbidity and mortality in high-risk nondiabetic patients during critical illness. Potential synergy between different classes of drugs with metabolic and/or cardiovascular protective properties merits further investigation.

Newer Doppler echocardiography techniques in assessment of heart function in obese patients

Obesity is one of the major health problems of modem society. The prevalence of this condition has increased at an alarming rate, especially the most severe form (body mass index >40 kg/m2). The cardiovascular problems that generally accompany obesity are the focus of a large number of studies. Conventional echogram and more current modalities, such as tissue Doppler, strain and strain rate are valuable tools for the detection of subclinical dysfunction and the early diagnosis and treatment of patients.

Hepatic peroxisome proliferator-activated receptor-γ-fat-specific protein 27 pathway contributes to obesity-related hypertension via afferent vagal signals

AIMS

Obesity is commonly associated with hypertension. Increased sympathetic tonus in obese subjects contributes to the underlying mechanism. However, the precise mechanisms whereby obesity induces this sympathetic activation remain unclear. Hepatic peroxisome proliferator-activated receptor (PPAR)-γ2 expression, which is reportedly upregulated during obesity development, affects sympathetic activation via hepatic vagal afferents. Herein, we report involvement of this neuronal relay in obesity-related hypertension.

METHODS AND RESULTS

Peroxisome proliferator-activated receptor-γ and a direct PPARγ target, fat-specific protein 27 (Fsp27), were adenovirally overexpressed or knocked down in the liver, in combination with surgical dissection or pharmacological deafferentation of the hepatic vagus. Adenoviral PPARγ2 expression in the liver raised blood pressure (BP) in wild-type but not in β1/β2/β3 adrenergic receptor-deficient mice. In addition, knockdown of endogenous PPARγ in the liver lowered BP in murine obesity models. Either surgical dissection or pharmacological deafferentation of the hepatic vagus markedly blunted BP elevation in mice with diet-induced and genetically-induced obesity. In contrast, BP was not elevated in other models of hepatic steatosis, DGAT1 and DGAT2 overexpressions, in which PPARγ is not upregulated in the liver. Thus, hepatic PPARγ upregulation associated with obesity is involved in BP elevation during obesity development. Furthermore, hepatic expression of Fsp27 raised BP and the effect was blocked by hepatic vagotomy. Hepatic Fsp27 is actually upregulated in murine obesity models and its knockdown reversed BP elevation.

CONCLUSION

The hepatic PPARγ-Fsp27 pathway plays important roles in the development of obesity-related hypertension via afferent vagal signals from the liver.

Serum 25-hydroxyvitamin D concentrations are associated with prevalence of metabolic syndrome and various cardiometabolic risk factors in US children and adolescents based on assay-adjusted serum 25-hydroxyvitamin D data from NHANES 2001-2006

BACKGROUND

The effect of assay drifts over time on serum 25-hydroxyvitamin D [25(OH)D] concentrations were not accounted for in previous national survey studies. Thus, previously reported associations between 25(OH)D with cardiometabolic risk factors using data from NHANES were likely over- or underestimated. Moreover, associations between serum 25(OH)D and metabolic syndrome (MetSyn), insulin resistance (IR), and inflammation are unclear in children.

OBJECTIVE

The relation between serum 25(OH)D and cardiometabolic risk factors in US children was investigated by using updated 25(OH)D data.

DESIGN

This study was based on newly updated serum 25(OH)D data, which were released by the National Center for Health Statistics in November 2010. Data from 3 cycles of NHANES (2001-2002, 2003-2004, and 2005-2006) for 5867 adolescents, aged 12-19 y, were used to study the association, by multivariate-adjusted regression, between serum 25(OH)D and prevalence of MetSyn and several cardiometabolic risk factors.

RESULTS

The likelihood of having MetSyn was significantly higher in the first tertile of serum 25(OH)D than in the third tertile of 25(OH)D (odds ratio: 1.71; 95% CI: 1.11, 2.65; P < 0.01). Waist circumference (P < 0.0001), systolic blood pressure (P = 0.01), and homeostatic model assessment-insulin resistance index (P = 0.001) were inversely related and HDL cholesterol (P < 0.0001) was directly related with serum 25(OH)D. No association was observed between 25(OH)D and C-reactive protein (P = 0.18).

CONCLUSIONS

On the basis of assay-adjusted data, serum 25(OH)D was significantly associated with several cardiometabolic risk factors regardless of obesity. In children, given the negative outcomes associated with poor vitamin D status and MetSyn, consideration of vitamin D supplementation in reversing cardiometabolic risk factors appears to be warranted.

Cardiovascular dysfunction in obesity and new diagnostic imaging techniques: the role of noninvasive image methods

Obesity is a major public health problem affecting adults and children in both developed and developing countries. This condition often leads to metabolic syndrome, which increases the risk of cardiovascular disease. A large number of studies have been carried out to understand the pathogenesis of cardiovascular dysfunction in obese patients. Endothelial dysfunction plays a key role in the progression of atherosclerosis and the development of coronary artery disease, hypertension and congestive heart failure. Noninvasive methods in the field of cardiovascular imaging, such as measuring intima-media thickness, flow-mediated dilatation, tissue Doppler, and strain, and strain rate, constitute new tools for the early detection of cardiac and vascular dysfunction. These techniques will certainly enable a better evaluation of initial cardiovascular injury and allow the correct, timely management of obese patients. The present review summarizes the main aspects of cardiovascular dysfunction in obesity and discusses the application of recent noninvasive imaging methods for the early detection of cardiovascular alterations.

CPAP treatment in the coexistence of obstructive sleep apnea syndrome and metabolic syndrome, results of one year follow up

OBJECTIVE

To investigate the effect of one year continuous positive airway pressure (CPAP) treatment on metabolic syndrome (MS) prevalence and components in patients diagnosed with both obstructive sleep apnea syndrome (OSAS) and metabolic syndrome.

METHODS

This was a single center, observational prospective cohort study. 38 patients who were diagnosed with OSAS after polysomnographic analysis in sleep laboratory and diagnosed with MS according to National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) guideline and underwent CPAP treatment were followed for one year. After the 1 year of follow up period on CPAP treatment, the prevalence of MS was evaluated again.

RESULTS

20 (13 male, 7 female) of 38 patients completed the entire study. Mean age was 50+/-7.7.4 patients were under treatment for diabetes mellitus (DM), 9 for hypertension (HT). After one year of follow up on CPAP treatment, the prevalence of MS decreased by 45%. When each components of MS were evaluated, no significant difference was found in fasting blood glucose, triglyceride levels and systolic and diastolic blood pressure after treatment (p>0.05). However, significant difference was observed in waist circumference (p=0.002), HDL cholesterol (p=0.001) and BMI (p=0.01) after treatment.

DISCUSSION

If MS accompanies OSAS, which is a cardiovascular risk factor by itself, treatment indications of CPAP should be reevaluated. Thus, if OSA patients meet the criteria of MS even though they do not have obvious DM, HT and hyperlipidemia, initiating CPAP treatment at lower AHI levels may contribute to the prevention and development of cardiovascular disease.

Obesity and hypertension: mechanisms, cardio-renal consequences, and therapeutic approaches

The increasing prevalence of obesity in the industrialized world is causing an alarming epidemic. Almost 70% of American adults are overweight or obese. The link between increasing body weight and hypertension is well established. Obesity hypertension through metabolic, endocrinic, and systemic hemodynamic alteration causes structural vascular and cardiac adaptations that trigger concentric, eccentric left ventricular hypertrophy and electrophysiological changes, which may increase the risk for congestive heart failure and sudden cardiac death as a result of arrhythmias. The increased renal blood flow in conjunction with a decreased renal vascular resistance causes renal hyperperfusion and hyperfiltration. Such changes lead to glomerulomegaly, focal segmental glomerulosclerosis, tubulointerstitial inflammation, and fibrosis that characterize the renal damage in obese hypertensive subjects. We propose that weight reduction, with the addition of other nonpharmacological approaches that included exercise and reduction in alcohol intake, should be the first choice to treat obesity hypertension. Salt restriction may be helpful only in salt-sensitive patients. The benefits of diet in obese patients include improvement of insulin sensitivity, reduction in sympathetic nervous and renin angiotensin system activities, and restoration of leptin sensitivity. As a consequence of these and other metabolic changes, the previously described systemic and renal hemodynamic alterations improved and the cardiovascular and renal morphological changes induced by obesity were lessened. After reviewing the medications available, we believe that owing to the cardiovascular and renal morbidity and mortality that characterized obesity hypertension, the ACEI or ARBs offer the best cardio-renal protection and should be the pharmacologic treatment of choice. If these alone do not control BP adequately, then a low-dose diuretic should be added as a second approach. Although we strongly believe in our proposal, more multicenter long-term clinical pharmacological trials are needed to evaluate the efficacy and safety of the antihypertensive approaches in the treatment of obesity hypertension.

Targeting melanocortin receptors: an approach to treat weight disorders and sexual dysfunction

The melanocortin system has multifaceted roles in the control of body weight homeostasis, sexual behaviour and autonomic functions, and so targeting this pathway has immense promise for drug discovery across multiple therapeutic areas. In this Review, we first outline the physiological roles of the melanocortin system, then discuss the potential of targeting melanocortin receptors by using MC3 and MC4 agonists for treating weight disorders and sexual dysfunction, and MC4 antagonists to treat anorectic and cachectic conditions. Given the complexity of the melanocortin system, we also highlight the challenges and opportunities for future drug discovery in this area.

Management of hypertension in diabetes mellitus

Overall, approximately 40% of diabetic patients have hypertension at the time of diagnosis of diabetes and a similar percentage may develop hypertension during their follow-up. Factors contributing to this high prevalance of hypertension in diabetes include obesity, old age, insulin resistance, increased extracelluar volume, diabetic nephropathy and increased arterial stiffness. Well-conducted clinical trials that have been completed in the last decade demonstrated a major impact of hypertension on the micro- and macrovascular complications of diabetes and remarkable benefits of its control. Based on this large trial database, the currently accepted level of blood pressure used in diabetes for definition and target of therapy is 130/80 mmHg. Dietary and behavioral lifestyle modifications should be an intergral part of any management regimen. These include weight reduction, low sodium diet, exercise, moderate alcohol intake and smoking cessation. Effective control of blood pressure to target levels is more important than the drug(s) used. Combination drug therapy is needed frequently to achieve a target blood pressure. Although blockers of the renin-angiotensin-aldosterone system seem to have a favorable effect in diabetes, high-level evidence suggests that low-dose thiazide diuretics, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers and calcium channel blockers are all good choices, both as initial and add-on therapy. Frequently, more than one drug is needed, and a low-dose thiazide diuretic combined with an angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker is a commonly used effective combination. Other drugs that can be added include calcium channel blockers and β-blockers. In certain clinical situations, specific drug classes are indicated. These include angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers in the case of diabetic nephropathy, β-blockers in the case of ischemic heart disease, and calcium channel blockers and loop diuretics in the case of advanced renal insufficiency, where the use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers carries a significant risk of hyperkalemia.

Operative risk factors in the metabolic syndrome: is it lipids and high blood pressure or are there direct vascular effects of insulin resistance and obesity?

The metabolic syndrome is associated with an increased risk for cardiovascular disease. Dyslipidemia, high blood pressure, and impaired glucose tolerance, components of the metabolic syndrome, are all clearly atherogenic. Insulin resistance is an important correlate of other risk factors. Excess abdominal fat, as often seen in overweight people and commonly observed in obese individuals, is the single most important central feature of the metabolic syndrome. In addition to insulin resistance, an excess amount of abdominal fat is associated with all the features of metabolic clustering. Adipocytes secrete several peptide hormones that have been related to the metabolic syndrome and related cardiovascular disease. The role of traditional versus novel adipose tissue-related risk factors in the background of atherosclerosis in the metabolic syndrome are discussed.

Insulin resistance and atherosclerosis

Considerable evidence supports the association between insulin resistance and vascular disease, and this has led to wide acceptance of the clustering of hyperlipidemia, glucose intolerance, hypertension, and obesity as a clinical entity, the metabolic syndrome. While insulin resistance, by promoting dyslipidemia and other metabolic abnormalities, is part of the proatherogenic milieu, it is possible that insulin resistance itself in the vascular wall does not promote atherosclerosis. Recent findings suggest that insulin resistance and atherosclerosis could represent independent and ultimately maladaptive responses to the disruption of cellular homeostasis caused by the excess delivery of fuel.

Angiotensin II type 2 receptor agonist directly inhibits proximal tubule sodium pump activity in obese but not in lean Zucker rats

We have reported recently that the renal angiotensin II type 2 (AT2) receptors are upregulated and involved in promoting natriuresis/diuresis in obese but not in lean Zucker rats. In the present study, we tested the hypothesis that there is an enhanced AT2 receptor signaling via NO/cGMP pathway leading to greater inhibition of the Na(+), K(+)-ATPase (NKA) activity in the proximal tubules (PT) of obese rather than lean Zucker rats. The AT2 agonist CGP42112 (0.1 to 100 nmol/L) inhibited (33% at 100 nmol/L) the NKA activity in the PTs of obese but not in lean Zucker rats. The AT2 antagonist PD123319 (1 micromol/L), not the angiotensin II type 1 antagonist losartan (1 micromol/L), significantly diminished the CGP42112-induced inhibition of the NKA activity in obese rats. The AT2 agonist (10 nmol/L)-induced NKA inhibition was abolished by the soluble guanylate cyclase inhibitor 1H-[1,2,4] oxadiazolo-[4,3-a] quinoxalin-1-one (10 micromol/L), the NO synthase inhibitor NG-nitro-L-arginine methyl ester (100 micromol/L), and the protein kinase G inhibitor K1388 (2 micromole/L). CGP42112 (10 nmol/L) caused an increase in serine phosphorylation of NKA alpha1-subunit in PT of obese rats. Measurement of cGMP and NO revealed that CGP42112 (0.1 to 100 nmol/L) increased cGMP and NO accumulation in the PTs of obese but not lean rats. The CGP42112-induced stimulation of NO and cGMP was blocked by PD123319 (1 micromol/L), NG-nitro-L-arginine methyl ester (100 micromol/L), and 1H-[1,2,4] oxadiazolo-[4,3-a] quinoxalin-1-one (10 micromol/L) but not by losartan (1 micromol/L). The data suggest that the AT2 receptor activation via stimulation of the NO/cGMP/protein kinase G pathway directly inhibits the tubular NKA activity that provides as a mechanism responsible for the AT2 receptor-mediated natriuresis in obese but not in lean Zucker rats.