Association of resistin and adiponectin with different clinical blood pressure phenotypes

Resistin/uric acid index as a marker of metabolic syndrome in females with obesity

BACKGROUND

The resistin/uric index has been considered a prognostic factor for identifying young people with obesity. Obesity and Metabolic Syndrome (MS) are an important health problem in females.

AIMS

The objective of this work was to evaluate the relationship of resistin/acid uric index with Metabolic Syndrome on Caucasian females with obesity.

METHODS

We conducted a cross sectional study in 571 females with obesity. Measurements of anthropometric parameters, blood pressure, fasting blood glucose, insulin concentration, insulin resistance (HOMA-IR), lipid profile, C reactive protein, uric acid, resistin and prevalence of Metabolic Syndrome were determined. The resistin/uric acid index was calculated.

RESULTS

In total, 249 subjects had MS (43.6%). We detected higher levels in the following parameters (Delta; p values); waist circumference (3.1 ± 0.5 cm; p = 0.04), systolic blood pressure (5.3 ± 3.6 mmHg; p = 0.01), diastolic blood pressure (2.3 ± 0.4 mmHg; p = 0.02), glucose levels (7.5 ± 0.9 mg/dL; p = 0.01), insulin levels (2.5 ± 0.3 UI/L; p = 0.02), HOMA-IR (0.7 ± 0.2 units; p = 0.03), uric acid levels (0.9 ± 0.2 mg/dl; p = 0.01), resistin levels (4.1 ± 0.4 ng/dl; p = 0.01) and resistin/uric acid index (0.61 ± 0.01 mg/dl; p = 0.02) in subjects of the high resistin/uric acid index group than low index group. Logistic regression analysis reported a high percentage of hyperglycemia (OR = 1.77, 95% CI = 1.10-2.92; p = 0.02), hypertension (OR = 1.91, 95% CI = 1.36-3.01; p = 0.01), central obesity (OR = 1.48, 95% CI = 1.15-1.84; p = 0.03) and metabolic syndrome percentage (OR = 1.71, 95% CI = 1.22-2.69; p = 0.02) in high resistin/uric acid index group.

CONCLUSIONS

Resistin/uric acid index is related with Metabolic syndrome (MS) risk and criteria of it in a population of Caucasian females with obesity and this index is a correlated with glucose levels, insulin levels and insulin resistance (HOMA-IR).

Serum adipokine levels in patients with type 1 diabetes are associated with degree of obesity but only resistin is independently associated with atherosclerosis markers

PURPOSE

The role of adipokines in causing inflammation and insulin resistance in normal weight and obese patients is generally well studied. However, there are often conflicting results regarding their levels in type 1 diabetes mellitus (T1DM) patients and their relationship to micro- and macrovascular disease. We therefore investigated which serum adipokine levels are independently associated with markers of early atherosclerosis and microvascular complications in patients with T1DM.

METHODS

A cross-sectional study was performed in the Diabetes Outpatient Clinic of Hippokrateion General Hospital, Thessaloniki, Greece. Sixty T1DM patients (30 females, mean age 38.8 ± 10.6 years, mean diabetes duration 17.4 ± 9.9 years) were included. Plasma adiponectin, leptin, and resistin, carotid artery intima media thickness (cIMT), and arterial stiffness (pulse wave velocity, PWV/SpygmoCor CP System and Mobil-O-Graph 24 h PWA) were assessed.

RESULTS

Leptin and resistin levels were significantly higher in overweight and obese patients (p = 0.002 and p = 0.039, respectively). Adiponectin was the only adipokine negatively correlated with BMI (r_s =  - 0.41, p = 0.001). We report a bivariate association between serum adiponectin levels and retinopathy (p = 0.007). Resistin was the only adipokine that showed significant correlation with systolic (r_s = 0.42, p = 0.001) and diastolic (r_s = 0.29, p = 0.024) hypertension and PWV (p = 0.035).

CONCLUSIONS

Serum adipokine levels demonstrate similar bivariate associations with anthropometric variables in patients with T1DM to those in normal weight subjects. Although microvascular complications are associated with serum adipokine levels by bivariate analysis, only resistin, an inflammatory marker, is independently associated with arterial stiffness in patients with T1DM.

The paradox of the role of resistin in early-onset obesity hypertension: A comparative study among four Chinese adult subgroups

Objective: To explore the role of resistin in the onset and development of obesity-related hypertension.Methods: Resistin serum levels were tested by ELISA in 153 adult subjects among four characteristic Chinese adult physical examination groups. Waist circumference (WC), body mass index (BMI), systolic blood pressure (SB), diastolic blood pressure (DB), and other clinical laboratory data were collected. Following, correlations between research index and differences between groups were analyzed using SPSS.Results: Serum resistin levels statistically significantly negatively correlated with SB, DB and BMI, but statistically significantly positively correlated with serum creatinine (SCR) and serum albumin (ALB), even after adjustment for age and/or gender. The serum level of resistin in the normal healthy subject group (NH) was higher than in other groups.Conclusions: Resistin's role in the onset of obesity-related hypertension may be more important than what has been previously assumed. More pathway substances in the early onset of obesity-related hypertension should be tested.Abbreviations: WC, waist circumference; GGT, Gamma-glutamyltransferase; ALB, Albumin; ALT, Alanine aminotransferase; LDL, Low density lipoprotein cholesterol; TG, Triglyceride; HDLC, High density lipoprotein cholesterol; FA Fructosamine; SCR, serum creatinine; IB, Indirect bilirubin; ALP, Alkaline phosphatase; CB, Conjugated bilirubin; UREA, Urea; Ua, Uric acid; FBG, fasting blood glucose; TC, Total cholesterol; TB, Total bilirubin; TP, Total protein; TC/HDLC, TC/HDLC ratio; SB, systolic blood pressure; DB, diastolic blood pressure.

Cardiovascular and Metabolic Crosstalk in the Brain: Leptin and Resistin

Leptin and resistin are cytokines whose plasma levels correlate with adiposity. Leptin is a hormone synthesised and released from adipocytes and can be transported into the brain. Resistin is produced in adipocytes in rodents and in macrophages in humans, particularly macrophages that have infiltrated adipose tissue. Both hormones can act within the brain to influence sympathetic nerve activity. Leptin appears to have a generalised sympatho-excitatory actions whilst resistin appears to increase sympathetic nerve activity affecting the cardiovascular system but inhibits sympathetic nerve activity to brown adipose tissue, which contrasts with leptin. Since both hormones can be elevated in conditions of metabolic dysfunction, interactions/crosstalk between these two hormones in the brain is a real possibility. This review describes the current knowledge regarding such crosstalk within the central nervous system. The evidence suggests that with respect to sympathetic nerve activity, crosstalk between leptin and resistin can elicit enhanced sympatho-excitatory responses to the kidneys. In contrast, with respect to food intake, resistin has weaker effects, but in regard to insulin secretion and thermogenesis, leptin and resistin have opposing actions. Thus, in conditions in which there is increased resistin and leptin levels, the result of crosstalk in the central nervous system could contribute to worse cardiovascular and metabolic complications.

Characteristics and control of the 24-hour ambulatory blood pressure in patients with metabolic syndrome

Asian countries are facing an increasing prevalence of metabolic syndrome (MetS), which may aggravate the burden of cardiovascular diseases in this region. MetS is closely associated with ambulatory blood pressure (BP). Patients with MetS, compared to those without, had a twofold higher risk of new-onset office, home, or ambulatory hypertension. Furthermore, the risk of new-onset MetS in patients with white-coat, masked and sustained hypertension was also doubled compared to normotensives. High-risk masked hypertension and blunted nighttime BP dipping are common in patients with MetS, suggesting perfect 24-hour BP control with long-acting antihypertensive drugs and early initiation of combination therapy might be especially important for patients with MetS.

Adipokines: New Potential Therapeutic Target for Obesity and Metabolic, Rheumatic, and Cardiovascular Diseases

Besides its role as an energy storage organ, adipose tissue can be viewed as a dynamic and complex endocrine organ, which produces and secretes several adipokines, including hormones, cytokines, extracellular matrix (ECM) proteins, and growth and vasoactive factors. A wide body of evidence showed that adipokines play a critical role in various biological and physiological functions, among which feeding modulation, inflammatory and immune function, glucose and lipid metabolism, and blood pressure control. The aim of this review is to summarize the effects of several adipokines, including leptin, diponectin, resistin, chemerin, lipocalin-2 (LCN2), vaspin, omentin, follistatin-like 1 (FSTL1), secreted protein acidic and rich in cysteine (SPARC), secreted frizzled-related protein 5 (SFRP5), C1q/TNF-related proteins (CTRPs), family with sequence similarity to 19 member A5 (FAM19A5), wingless-type inducible signaling pathway protein-1 (WISP1), progranulin (PGRN), nesfatin-1 (nesfatin), visfatin/PBEF/NAMPT, apelin, retinol binding protein 4 (RPB4), and plasminogen activator inhibitor-1 (PAI-1) in the regulation of insulin resistance and vascular function, as well as many aspects of inflammation and immunity and their potential role in managing obesity-associated diseases, including metabolic, osteoarticular, and cardiovascular diseases.

Mechanistic Links Between Obesity, Diabetes, and Blood Pressure: Role of Perivascular Adipose Tissue

Obesity is increasingly prevalent and is associated with substantial cardiovascular risk. Adipose tissue distribution and morphology play a key role in determining the degree of adverse effects, and a key factor in the disease process appears to be the inflammatory cell population in adipose tissue. Healthy adipose tissue secretes a number of vasoactive adipokines and anti-inflammatory cytokines, and changes to this secretory profile will contribute to pathogenesis in obesity. In this review, we discuss the links between adipokine dysregulation and the development of hypertension and diabetes and explore the potential for manipulating adipose tissue morphology and its immune cell population to improve cardiovascular health in obesity.

Association between serum resistin concentration and hypertension: A systematic review and meta-analysis

Objectives

Recent studies have suggested the involvement of adipokines in the pathogenesis of cardiovascular diseases, including hypertension. In this study, we evaluated the significance of serum resistin levels in hypertensive patients using a meta-analysis approach.

Materials and Methods

Relevant articles were retrieved by searching the following databases: PubMed, Embase, Ovid Medline, ISI Web of Knowledge. The retrieved studies were subjected to a thorough screening procedure to identify case-control studies that contained the required data. Data were extracted from each study and analyzed by Stata software and Review Manager software. In total, 14 case-control studies, containing 718 hypertensive patients and 645 normotensive controls, were included in this study. The major result of the meta-analysis revealed a statistically significant association between serum resistin concentration and hypertension (SMD = 0.85, 95% CI: [0.15, 1.54]), and the association was more obvious in Asian and Hispanic populations, diabetic population and studies with larger size cohorts. Publication bias was a low probability event for overall comparisons.

Conclusions

Based on our results, we conclude that serum resistin level in hypertensive patients is higher than normotensive controls, indicating resistin might be a risk factor for hypertension.

Linking resistin, inflammation, and cardiometabolic diseases

Adipose tissue secretes a variety of bioactive substances that are associated with chronic inflammation, insulin resistance, and an increased risk of type 2 diabetes mellitus. While resistin was first known as an adipocyte-secreted hormone (adipokine) linked to obesity and insulin resistance in rodents, it is predominantly expressed and secreted by macrophages in humans. Epidemiological and genetic studies indicate that increased resistin levels are associated with the development of insulin resistance, diabetes, and cardiovascular disease. Resistin also appears to mediate the pathogenesis of atherosclerosis by promoting endothelial dysfunction, vascular smooth muscle cell proliferation, arterial inflammation, and the formation of foam cells. Thus, resistin is predictive of atherosclerosis and poor clinical outcomes in patients with cardiovascular disease and heart failure. Furthermore, recent evidence suggests that resistin is associated with atherogenic dyslipidemia and hypertension. The present review will focus on the role of human resistin in the pathogeneses of inflammation and obesity-related diseases.

Resistin, an Adipokine with Non-Generalized Actions on Sympathetic Nerve Activity

The World Health Organization has called obesity a global epidemic. There is a strong association between body weight gain and blood pressure. A major determinant of blood pressure is the level of activity in sympathetic nerves innervating cardiovascular organs. A characteristic of obesity, in both humans and in animal models, is an increase in sympathetic nerve activity to the skeletal muscle vasculature and to the kidneys. Obesity is now recognized as a chronic, low level inflammatory condition, and pro-inflammatory cytokines are elevated including those produced by adipose tissue. The most well-known adipokine released from fat tissue is leptin. The adipokine, resistin, is also released from adipose tissue. Resistin can act in the central nervous system to influence the sympathetic nerve activity. Here, we review the effects of resistin on sympathetic nerve activity and compare them with leptin. We build an argument that resistin and leptin may have complex interactions. Firstly, they may augment each other as both are excitatory on sympathetic nerves innervating cardiovascular organs; In contrast, they could antagonize each other's actions on brown adipose tissue, a key metabolic organ. These interactions may be important in conditions in which leptin and resistin are elevated, such as in obesity.

Single nucleotide polymorphism-single nucleotide polymorphism interactions among inflammation genes in the genetic architecture of blood pressure in the Framingham Heart Study

BACKGROUND

Hypertension is a major global health burden, but, although systolic and diastolic blood pressure (BP) each have estimated heritability of at least 30%, <3% of their variance has been attributed to particular genetic variants. Few studies have shown interactions between pairs of single nucleotide polymorphisms (SNPs) to be associated with BP. Although many studies use a Bonferroni correction for multiple testing to control type I error, thereby potentially reducing power, false discovery rate (FDR) approaches are also used in genome-wide studies. Renal ion balance genes have been associated with BP regulation, but, although inflammation has been studied in connection with BP, few studies have reported associations between inflammation genes and BP.

METHODS

We analyzed SNP-SNP interactions among 31 SNPs from genes involved in renal ion balance and 30 SNPs from genes involved in inflammation using data from the Framingham Heart Study.

RESULTS

No evidence of association was found for interactions among renal ion balance SNPs for either systolic or diastolic BP. A group of 3 interactions involving 6 inflammation genes (IKBKB-NFKBIA, IKBKE-CHUK, and ADIPOR2-RETN) showed evidence of association with diastolic BP with an FDR of 4.2%; no single interaction reached experiment-wide significance.

CONCLUSIONS

This study identified promising and biologically plausible candidates for interactions between inflammation genes that may be associated with DBP. Analysis using the FDR may allow detection of signals in the presence of modest noise (false positives) that a stringent approach based on Bonferroni-corrected P value thresholds may miss.

Vitamin D and vascular disease: the current and future status of vitamin D therapy in hypertension and kidney disease

Over the past decade, vitamin D has generated considerable interest as potentially having important effects on the vasculature and the kidney. Animal and human data indicate that vitamin D suppresses the activity of the renin-angiotensin system and improves endothelial function. Observational studies in humans suggest that low 25-hydroxyvitamin D (25[OH]D) levels are associated with a higher risk of hypertension. However, findings from randomized trials of vitamin D supplementation (with cholecalciferol or ergocalciferol) to lower blood pressure are inconsistent, possibly stemming from variability in study population, sample size, vitamin D dose, and duration. Supplementation with activated vitamin D (i.e., 1,25-dihydroxyvitamin D or analogues) in patients with chronic kidney disease reduces urine albumin excretion, an important biomarker for future decline in renal function. These studies are reviewed, with special emphasis on recent findings. Definitive studies are warranted to elucidate the effects of vitamin D supplementation on mechanisms of hypertension and kidney disease.

Sympathetic nervous system in obesity-related hypertension: mechanisms and clinical implications

Obesity markedly increases the risk of hypertension and cardiovascular disease, which may be related to activation of the sympathetic nervous system (SNS). Sympathetic overactivity directly and indirectly contributes to blood pressure (BP) elevation in obesity, including stimulation of the renin-angiotensin-aldosterone system (RAAS). The adipocyte-derived peptide leptin suppresses appetite, increases thermogenesis, but also raises SNS activity and BP. Obese individuals exhibit hyperleptinemia but are resistant to its appetite-suppressing actions. Interestingly, animal models of obesity exhibit preserved sympathoexcitatory and pressor actions of leptin, despite resistance to its anorexic and metabolic actions, suggesting selective leptin resistance. Disturbance of intracellular signaling at specific hypothalamic neural networks appears to underlie selective leptin resistance. Delineation of these pathways should lead to novel approaches to treatment. In the meantime, treatment of obesity-hypertension has relied on antihypertensive drugs. Although sympathetic blockade is mechanistically attractive in obesity-hypertension, in practice its effects are disappointing because of adverse metabolic effects and inferior outcomes. On the basis of subgroup analyses of obese patients in large randomized clinical trials, drugs such as diuretics and RAAS blockers appear superior in preventing cardiovascular events in obesity--hypertension. An underused alternative approach to obesity-hypertension is induction of weight loss, which reduces circulating leptin and insulin, partially reverses resistance to these hormones, decreases sympathetic activation and improves BP and other risk factors. Though weight loss induced by lifestyle is often modest and transient, carefully selected pharmacological weight loss therapies can produce substantial and sustained antihypertensive effects additive to lifestyle interventions.

Centrally administered resistin enhances sympathetic nerve activity to the hindlimb but attenuates the activity to brown adipose tissue

Resistin, an adipokine, is believed to act in the brain to influence energy homeostasis. Plasma resistin levels are elevated in obesity and are associated with metabolic and cardiovascular disease. Increased muscle sympathetic nerve activity (SNA) is a characteristic of obesity, a risk factor for diabetes and cardiovascular disease. We hypothesized that resistin affects SNA, which contributes to metabolic and cardiovascular dysfunction. Here we investigated the effects of centrally administered resistin on SNA to muscle (lumbar) and brown adipose tissue (BAT), outputs that influence cardiovascular and energy homeostasis. Overnight-fasted rats were anesthetized, and resistin (7 μg) was administered into the lateral cerebral ventricle (intracerebroventricular). The lumbar sympathetic nerve trunk or sympathetic nerves supplying BAT were dissected free, and nerve activity was recorded. Arterial blood pressure, heart rate, body core temperature, and BAT temperature were also recorded. Responses to resistin or vehicle were monitored for 4 h after intracerebroventricular administration. Acutely administered resistin increased lumbar SNA but decreased BAT SNA. Mean arterial pressure and heart rate, however, were not significantly affected by resistin. BAT temperature was significantly reduced by resistin, and there was a concomitant fall in body temperature. The findings indicate that resistin has differential effects on SNA to tissues involved in metabolic and cardiovascular regulation. The decreased BAT SNA and the increased lumbar SNA elicited by resistin suggest that it may contribute to the increased muscle SNA and reduced energy expenditure observed in obesity and diabetes.

The association of plasma resistin with dietary sodium manipulation, the renin-angiotensin-aldosterone system, and 25-hydroxyvitamin D3 in human hypertension

OBJECTIVE

Both resistin and vitamin D have been associated with the renin-angiotensin-aldosterone system (RAAS). We investigated the association between resistin and the RAAS, and resistin and vitamin D under controlled dietary sodium conditions.

DESIGN

Retrospective cross-sectional study of subjects from the HyperPATH Consortium, who were maintained in high dietary sodium (HS) and low dietary sodium (LS) balance for 1 week each.

PATIENTS

Caucasian subjects with hypertension (n=177).

MEASUREMENTS

25-Hydroxyvitamin D (25[OH]D) levels were used to assess vitamin D status. Plasma resistin and RAAS measures were evaluated on each dietary intervention.

RESULTS

Resistin levels were significantly higher in LS, where RAAS activity was high, when compared with HS balance, where RAAS activity was suppressed (6.36 vs 5.86 μg/l, P < 0.0001); however, resistin concentrations were not associated with plasma renin activity or serum aldosterone on either diet. 25(OH)D levels were positively and independently associated with resistin in both dietary conditions (HS: β=0.400, P-trend=0.027; LS: β=0.540, P-trend=0.014).

CONCLUSIONS

Dietary sodium loading reduced resistin levels, possibly by suppressing the RAAS; however, circulating RAAS components were not related to resistin concentrations within each specific dietary sodium condition. 25(OH)D was positively associated with resistin and may be involved in resistin regulation through an unknown mechanism. Further studies to understand resistin regulation in human hypertension better are warranted.

Novel adiponectin-resistin (AR) and insulin resistance (IRAR) indexes are useful integrated diagnostic biomarkers for insulin resistance, type 2 diabetes and metabolic syndrome: a case control study

Background

Adiponectin and resistin are adipokines which modulate insulin action, energy, glucose and lipid homeostasis. Meta-analyses showed that hypoadiponectinemia and hyperresistinemia are strongly associated with increased risk of insulin resistance, type 2 diabetes (T2DM), metabolic syndrome (MS) and cardiovascular disease. The aim of this study was to propose a novel adiponectin-resistin (AR) index by taking into account both adiponectin and resistin levels to povide a better indicator of the metabolic homeostasis and metabolic disorders. In addition, a novel insulin resistance (IR_AR) index was proposed by integration of the AR index into an existing insulin resistance index to provide an improved diagnostic biomarker of insulin sensitivity.

Methods

In this case control study, anthropometric clinical and metabolic parameters including fasting serum total adiponectin and resistin levels were determined in 809 Malaysian men (208 controls, 174 MS without T2DM, 171 T2DM without MS, 256 T2DM with MS) whose ages ranged between 40-70 years old. Significant differences in continuous variables among subject groups were confirmed by ANCOVA or MANCOVA test using 1,000 stratified bootstrap samples with bias corrected and accelerated (BCa) 95% CI. Spearman's rho rank correlation test was used to test the correlation between two variables.

Results

The AR index was formulated as 1+log₁₀(R₀)-log₁₀(A₀). The AR index was more strongly associated with increased risk of T2DM and MS than hypoadiponectinemia and hyperresistinemia alone. The AR index was more strongly correlated with the insulin resistance indexes and key metabolic endpoints of T2DM and MS than adiponectin and resistin levels alone. The AR index was also correlated with a higher number of MS components than adiponectin and resistin levels alone. The IR_AR index was formulated as log₁₀(I₀G₀)+log₁₀(I₀G₀)log₁₀(R₀/A₀). The normal reference range of the IR_AR index for insulin sensitive individuals was between 3.265 and 3.538. The minimum cut-off values of the IR_AR index for insulin resistance assessment were between 3.538 and 3.955.

Conclusions

The novel AR and IR_AR indexes are cost-effective, precise, reproducible and reliable integrated diagnostic biomarkers of insulin sensitivity for screening subjects with increased risk of future development of T2DM and MS.