Relationship between serum resistin concentrations and insulin resistance in nonobese, obese, and obese diabetic subjects

Obesity, inflammation, and insulin resistance

White adipose tissue (WAT) is considered an endocrine organ. When present in excess, WAT can influence metabolism via biologically active molecules. Following unregulated production of such molecules, adipose tissue dysfunction results, contributing to complications associated with obesity. Previous studies have implicated pro- and anti-inflammatory substances in the regulation of inflammatory response and in the development of insulin resistance. In obese individuals, pro-inflammatory molecules produced by adipose tissue contribute to the development of insulin resistance and increased risk of cardiovascular disease. On the other hand, the molecules with anti-inflammatory action, that have been associated with the improvement of insulin sensitivity, have your decreased production. Imbalance of these substances contributes significantly to metabolic disorders found in obese individuals. The current review aims to provide updated information regarding the activity of biomolecules produced by WAT.

Obesity as a risk and severity factor in rheumatic diseases (autoimmune chronic inflammatory diseases)

The growing body of evidence recognizing the adipose tissue (AT) as an active endocrine organ secreting bioactive mediators involved in metabolic and inflammatory disorders, together with the global epidemic of overweight and obesity, rise obesity as a hot topic of current research. The chronic state of low-grade inflammation present in the obese condition and the multiple pleiotropic effects of adipokines on the immune system has been implicated in the pathogenesis of several inflammatory conditions including rheumatic autoimmune and inflammatory diseases. We will discuss the main relevant evidences on the role of the AT on immune and inflammatory networks and the more recent evidences regarding the effects of obesity on the incidence and outcomes of the major autoimmune chronic inflammatory diseases.

Association of Resistin with Insulin Resistance and Factors of Metabolic Syndrome in North Indians

Metabolic syndrome (MetS) is a cluster of interrelated common clinical disorders. The role of resistin in insulin sensitivity and MetS is controversial till date. So, the aim of the present study was to investigate the relationship of plasma resistin levels with markers of the MetS in Indian subjects. In a case control study, total 528 subjects were selected for the study. 265 (194 male and 71 female) were cases (with MetS) and 263 (164 male and 99 female) were controls (without MetS). Required anthropometric measurements and calculations were carried out accordingly. All the Biochemical estimations were carried out according to standard protocol. Resistin level was measured by the standard protocol (By ELISA i.e. enzyme linked immunosorbent assay) as illustrated in the kit. Insulin level was also measured by the standard protocol as illustrated in the kit and insulin resistance was calculated by the standard procedures. Plasma resistin levels were significantly higher in cases compared with controls (male = 13.05 ± 4.31 vs. 7.04 ± 2.09 ng/ml; p ≤ 0.001 and female = 13.53 ± 4.14 vs. 7.42 ± 2.30 ng/ml; p ≤ 0.001). Plasma resistin levels were well correlated with waist circumference, glucose, triglycerides, waist/hip ratio, systolic and diastolic blood pressure, high density lipoprotein, total cholesterol, serum low density lipoprotein, serum very low density lipoprotein, insulin and insulin resistance. Plasma resistin levels were elevated in presence of the MetS and were associated with increased metabolic risk factors.

Weight gain reveals dramatic increases in skeletal muscle extracellular matrix remodeling

CONTEXT

In animal models of obesity, chronic inflammation and dysregulated extracellular matrix remodeling in adipose tissue leads to insulin resistance. Whether similar pathophysiology occurs in humans is not clear.

OBJECTIVE

The aim of this study was to test whether 10% weight gain induced by overfeeding triggers inflammation and extracellular matrix remodeling (gene expression, protein, histology) in skeletal muscle and sc adipose tissue in humans. We also investigated whether such remodeling was associated with an impaired metabolic response (hyperinsulinemic-euglycemic clamp).

DESIGN, SETTING, PARTICIPANTS, AND INTERVENTION

Twenty-nine free-living males were fed 40% over their baseline energy requirements for 8 weeks.

RESULTS

Ten percent body weight gain prompted dramatic up-regulation of a repertoire of extracellular matrix remodeling genes in muscle and to a lesser degree in adipose tissue. The amount of extracellular matrix genes in the muscle were directly associated with the amount of lean tissue deposited during overfeeding. Despite weight gain and impaired insulin sensitivity, there was no change in local adipose tissue or systemic inflammation, but there was a slight increase in skeletal muscle inflammation.

CONCLUSION

We propose that skeletal muscle extracellular matrix remodeling is another feature of the pathogenic milieu associated with energy excess and obesity, which, if disrupted, may contribute to the development of metabolic dysfunction.

Relationship between obesity, adipocytokines and inflammatory markers in type 2 diabetes: relevance for cardiovascular risk prevention

This study aimed to analyse the impact of obesity in type 2 diabetes (T2D) on adipocytokines (adiponectin, leptin and resistin) and inflammatory markers (TNF-α, IL-6 and hsCRP) as cardiovascular risk factors. A cross-sectional study comparing the basal levels of adipocytokines and inflammatory markers was done in 18 obese (BMI ≥ 30 kg/m²) (group A), 21 overweight (25 kg/m² ≤ BMI < 30 kg/m²) (group B), 25 non-obese T2D patients (group C) and 15 non-obese controls (group D). The lowest levels of adiponectin and the highest levels of leptin, resistin, TNF-α, IL-6 and hsCRP were found in group A. Adiponectin levels were significantly lower, and resistin, TNF-α, and hsCRP levels were elevated in group C vs. D. However, leptin and IL-6 levels differed significantly between groups A and B, but not between groups C and D. Moreover, we found a significant negative correlation between adiponectin and TNF-α, but not with other markers, which was independent of the presence of obesity. In contrast, leptin and resistin correlated with the inflammatory markers, and this correlation was obesity-dependent. Our results suggest that obesity influences cardiovascular risk primarily through changes in leptin and resistin and less efficiently at the level of adiponectin.

Adipokines and insulin action: A sensitive issue

Obesity is a major public health concern and a strong risk factor for insulin resistance, type 2 diabetes mellitus (T2DM), and cardiovascular disease. The last two decades have seen a reconsideration of the role of white adipose tissue (WAT) in whole body metabolism and insulin action. Adipose tissue-derived cytokines and hormones, or adipokines, are likely mediators of metabolic function and dysfunction. While several adipokines have been associated with obese and insulin-resistant phenotypes, a select group has been linked with insulin sensitivity, namely leptin, adiponectin, and more recently, adipolin. What is known about these insulin-sensitizing molecules and their effects in healthy and insulin resistant states is the subject of this review. There remains a significant amount of research to do to fully elucidate the mechanisms of action of these adipokines for development of therapeutics in metabolic disease.

Adipokines as potential biomarkers in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic systemic inflammatory autoimmune disease characterized by severe joint injury. Recently, research has been focusing on the possible identification of predictor markers of disease onset and/or progression, of joint damage, and of therapeutic response. Recent findings have uncovered the role of white adipose tissue as a pleiotropic organ not only specialized in endocrine functions but also able to control multiple physiopathological processes, including inflammation. Adipokines are a family of soluble mediators secreted by white adipose tissue endowed with a wide spectrum of actions. This review will focus on the recent advances on the role of the adipokine network in the pathogenesis of RA. A particular attention will be devoted to the action of these proteins on RA effector cells, and on the possibility to use circulating levels of adipokines as potential biomarkers of disease activity and therapeutic response.

Role of resistin in insulin resistance and obesity

Resistin is an adipose-derived hormone postulated to link adiposity to insulin resistance. Rodent animal experiments and in vitro experimental studies showed that resistin can induce insulin resistance, glucose and lipid metabolism disorders, and be closely related to metabolic syndrome. However, the specific mechanisms of action of resistin in humans are not clear. There is still controversy over the relationship between resistin and obesity. This review aims to elucidate the role of resistin in insulin resistance and discuss the relationship between resistin and obesity.

Adipokines, metabolic syndrome and rheumatic diseases

The metabolic syndrome (MetS) is a cluster of cardiometabolic disorders that result from the increasing prevalence of obesity. The major components of MetS include insulin resistance, central obesity, dyslipidemia, and hypertension. MetS identifies the central obesity with increased risk for cardiovascular diseases (CVDs) and type-2 diabetes mellitus (T2DM). Patients with rheumatic diseases, such as rheumatoid arthritis, osteoarthritis, systemic lupus erythematosus, and ankylosing spondylitis, have increased prevalence of CVDs. Moreover, CVD risk is increased when obesity is present in these patients. However, traditional cardiovascular risk factors do not completely explain the enhanced cardiovascular risk in this population. Thus, MetS and the altered secretion patterns of proinflammatory adipokines present in obesity could be the link between CVDs and rheumatic diseases. Furthermore, adipokines have been linked to the pathogenesis of MetS and its comorbidities through their effects on vascular function and inflammation. In the present paper, we review recent evidence of the role played by adipokines in the modulation of MetS in the general population, and in patients with rheumatic diseases.

Rheumatic diseases and obesity: adipocytokines as potential comorbidity biomarkers for cardiovascular diseases

Inflammation has been recognized as a common trait in the pathogenesis of multifactorial diseases including obesity, where a low-grade inflammation has been established and may be responsible for the cardiovascular risk related to the disease. Obesity has also been associated with the increased incidence and a worse outcome of rheumatoid arthritis (RA) and osteoarthritis (OA). RA is characterized by systemic inflammation, which is thought to play a key role in accelerated atherosclerosis and in the increased incidence of cardiovascular disease, an important comorbidity in patients with RA. The inflammatory process underlying the cardiovascular risk both in obesity and RA may be mediated by adipocytokines, a heterogeneous group of soluble proteins mainly secreted by the adipocytes. Many adipocytokines are mainly produced by white adipose tissue. Adipocytokines may also be involved in the pathogenesis of OA since a positive association with obesity has been found for weight-bearing and nonweight-bearing joints, suggesting that, in addition to local overload, systemic factors may contribute to joint damage. In this review we summarize the current knowledge on experimental models and clinical studies in which adipocytokines were examined in obesity, RA, and OA and discuss the potential of adipocytokines as comorbidity biomarkers for cardiovascular risk.

Serum resistin levels are associated with adiposity and insulin sensitivity in obese Hispanic subjects

BACKGROUND AND AIMS

Resistin is involved in the development of obesity and insulin resistance (IR) in mice and may play a similar role in humans through mechanisms that remain unresolved. The objective of this study was to characterize the relationship between resistin levels in obese subjects with and without IR among Hispanic subjects.

MATERIAL AND METHODS

A cross-sectional study was performed on 117 nondiabetic Hispanic subjects of both genders that were allocated into three study groups: A control group (n=47) of otherwise healthy individuals in metabolic balance, a group with obesity (OB) (n=36), and a group with obesity and IR (OB-IR) (n=34). Anthropometric and clinical characterization was carried out, and resistin levels were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

We found that resistin levels were higher in OB and OB-IR groups when compared to the control group (1331.79±142.15 pg/mL, 1266.28±165.97 pg/mL vs. 959.21±171.43 pg/mL; P<0.05), an effect that was not confounded by age (control, 34.04±10.00 years; OB, 37.30±10.78 years; and OB-IR, 35.67±10.15 years). In addition, we observed a significant correlation (P<0.001) between resistin levels and higher adiposity and insulin sensitivity (IS) in our cohort.

CONCLUSIONS

Our results suggest that higher resistin levels are associated with higher adiposity and lower IS among obese Hispanic subjects.

Resistin levels are related to fat mass, but not to body mass index in children

The relationship of resistin levels with obesity remains unclear. The aim of this study was to determine resistin levels in prepubertal children and adolescents and evaluate their association with anthropometric parameters and body composition. The study population included 420 randomly selected 6-8-year-old children and 712 children aged 12-16 years. Anthropometric data were measured and body mass index (BMI) and waist-to-hip and waist-to-height ratios were calculated. Body composition was assessed using an impedance body composition analyzer. Serum resistin levels were determined using a multiplexed bead immunoassay. Resistin levels were not significantly different between sexes. No significant differences in serum resistin concentrations were found between obese, overweight, and normal weight children at any age, and no significant correlations were observed between resistin concentrations and weight or BMI. However, resistin levels showed a significant positive correlation with fat mass in 12-16-year-old children, particularly in girls. In addition to describing serum resistin levels in prepubertal children and adolescents, our study suggests that resistin is related to body fat rather than to BMI in adolescents.

Resistin in serum and gingival crevicular fluid as a marker of periodontal inflammation and its correlation with single-nucleotide polymorphism in human resistin gene at -420

AIMS

Resistin is an adipocytokine, which have been studied for its role in insulin resistance and recently in inflammation. The aim of the present study is to assess the concentration of resistin in serum and gingival crevicular fluid (GCF) and to compare the levels between subjects with and without periodontitis and type 2 diabetes mellitus (T2DM) and to further correlate the resistin levels with the single-nucleotide polymorphism (SNP) at -420.

SETTING AND DESIGNS

A total of 96 subjects (48 males and 48 females) were divided on the basis of gingival index (GI), probing pocket depth (PD), clinical attachment level (CAL) and hemoglobin A1c levels into healthy (group 1, n = 24), uncontrolled-diabetes related periodontitis (group 2, n = 24), controlled-diabetes related periodontitis (group 3, n = 24) and chronic periodontitis without T2DM (group 4, n = 24).

MATERIALS AND METHODS

The GCF and serum levels of resistin were quantified using the enzyme-linked immunosorbent assay and compared among the study groups. Further, the association of the resistin levels with periodontal inflammation and SNP at -420 was studied.

RESULTS AND CONCLUSION

The resistin levels in GCF and serum from patients with periodontitis or diabetes mellitus related periodontitis (controlled or uncontrolled) were higher than that of healthy subjects and correlated positively with GI. Further, subjects with GG genotype at -420 showed significantly higher GI, PD, CAL as compared with genotype group CC. Resistin was detected in all serum and GCF samples and was significantly higher in periodontitis. Further, GG genotype at -420 was associated significantly with periodontal inflammation and resistin levels.

Circulating levels of the cytokines IL10, IFNγ and resistin in an obese mouse model of developmental programming

An infant's early developmental environment plays a pivotal role in the programming of its physiological phenotype. The identification of the factors in the maternal environment that mediate the effects of maternal obesity and diet is essential to the development of clinical intervention strategies. Maternal hyperglycaemia, hyperinsulinaemia, hypertriglyceridaemia, hyperleptinaemia and altered inflammatory cytokines concentrations are potentially important predictive factors of her future offspring's susceptibility to metabolic disease. Using a diet-induced obese mouse model, we have investigated which of these maternal factors could induce adverse metabolic programming in the offspring. Female C57Bl/6 mice were fed either laboratory chow (10% fat) or high fat diet (42% fat) for 10 weeks before mating and throughout gestation. At day 18 of pregnancy, maternal body weight, body composition and glucose tolerance were measured, as well as plasma insulin, adiponectin, RBP4, leptin, resistin and the inflammatory cytokines (IL6, IL10, IL12, IL1β, IFNγ, KC, TNF-α). At day 18 of pregnancy, high fat-fed dams were significantly heavier than the chow dams and had increased fat mass. High fat-fed dams had higher 5 h fasting blood glucose than chow dams and elevated plasma insulin. Although the obese dams had both reduced plasma adiponectin and resistin levels compared with lean dams, their plasma IL6, IL10 and IFNγ levels were all increased. High fat feeding in pregnancy leads to altered plasma concentrations of both adipokines and adipocytokines in the dam that may directly pass to the fetus and affect their development.

Resistin level in coronary artery disease and heart failure: the central role of kidney function

OBJECTIVES

The aim of this study was to evaluate resistin levels in patients with coronary artery disease (CAD) with or without chronic heart failure, in order to define its independent predictor.

METHODS

One hundred and seven outpatients with CAD were enrolled in the study and divided into three groups: CAD without left-ventricular systolic dysfunction (group 1); CAD with left-ventricular dysfunction without heart failure symptoms (group 2); CAD with overt heart failure (group 3). Plasma resistin was determined by ELISA.

RESULTS

Resistin progressively increased from group 1 (10.7±5.0 ng/ml) to groups 2 (11.8±5.8 ng/ml) and 3 (17.0±6.8 ng/ml), with the difference reaching statistical significance in group 3 versus groups 1 and 2 (P=0.001). A multivariable model of analysis demonstrated that the best predictor of plasma resistin level was the estimated glomerular filtration rate (P<0.001), indicating that reduction of kidney function was the main cause of the adipokine increase observed in patients with CAD and overt heart failure.

CONCLUSIONS

Our data confirm the rise of resistin plasma levels previously described in patients affected by chronic heart failure; however, in our study, this relationship seemed to be mediated mainly by the level of kidney function, and only partially by the severity of ventricular dysfunction.

Peripheral signalling involved in energy homeostasis control

The alarming prevalence of obesity has led to a better understanding of the molecular mechanisms controlling energy homeostasis. Regulation of energy intake and expenditure is more complex than previously thought, being influenced by signals from many peripheral tissues. In this sense, a wide variety of peripheral signals derived from different organs contributes to the regulation of body weight and energy expenditure. Besides the well-known role of insulin and adipokines, such as leptin and adiponectin, in the regulation of energy homeostasis, signals from other tissues not previously thought to play a role in body weight regulation have emerged in recent years. The role of fibroblast growth factor 21 (FGF21), insulin-like growth factor 1 (IGF-I), and sex hormone-binding globulin (SHBG) produced by the liver in the regulation of body weight and insulin sensitivity has been recently described. Moreover, molecules expressed by skeletal muscle such as myostatin have also been involved in adipose tissue regulation. Better known is the involvement of ghrelin, cholecystokinin, glucagon-like peptide 1 (GLP-1) and PYY(3-36), produced by the gut, in energy homeostasis. Even the kidney, through the production of renin, appears to regulate body weight, with mice lacking this hormone exhibiting resistance to diet-induced obesity. In addition, the skeleton has recently emerged as an endocrine organ, with effects on body weight control and glucose homeostasis through the actions of bone-derived factors such as osteocalcin and osteopontin. The comprehension of these signals will help in a better understanding of the aetiopathology of obesity, contributing to the potential development of new therapeutic targets aimed at tackling excess body fat accumulation.

Thermogenesis-based interventions for obesity and Type 2 diabetes mellitus

Obesity is one of the key noncommunicable diseases leading to significant comorbidities. In recent years, obesity has become a major public health issue and has threatened the wellbeing of millions of patients. Although there are multiple reasons for people becoming obese, sustained positive energy balance - energy intake is greater than energy expenditure - is the key for accumulating excess bodyfat. Prevention of obesity by lifestyle changes, healthy eating and increased physical activity are more cost effective than pharmacotherapy, bariatric surgery or ultimately treating complications of Type 2 diabetes mellitus (T2DM). Not all patients with obesity experience complications such as T2DM. The distribution of bodyfat is important in determining whether a person is obese and healthy or needs medical attention; however, the use of BMI alone will not differentiate this. Obesity patients with excess abdominal fat have the highest risk for T2DM, insulin resistance and thus, higher incidence of cardiovascular diseases. Obesity-associated complications can be reversed through healthy eating habits and increased duration and intensity of physical activity. Increasing work- and leisure-related physical activities increase the energy expenditure, having salutary effects on weightloss programs. Although treating symptoms of obesity and related disorders is important, it is not a solution for the obesity epidemic. Causes that lead to weight-gain need to be identified in individual patients, who should be educated about the causes of weight gain and ways to prevent it, and be provided with simple and practical interventions to lose weight.

Application of proteomics technology in adipocyte biology

Obesity and its associated complications have reached epidemic proportions in Western-type societies. Concomitantly, the obesity incidence in developing countries is increasing. One hallmark of obesity is the differentiation of pre-adipocytes into mature triglyceride-loaded adipocytes present in subcutaneous and visceral adipose tissue depots. This may ultimately lead to dysfunctional adipose tissue together with detrimental changes in the profiles of (pre-)adipocyte-secreted proteins, known as adipokines. Obesity-induced alterations in adipokine profiles contribute to the development of obesity-associated disorders. Consequently, the interest in the molecular events responsible for adipose tissue modifications during weight gain and weight loss as well as in the aetiology of obesity-associated disorders is growing. Molecular mechanisms involved in pre-adipocyte differentiation and alterations in adipokine profiles have been examined at the gene and protein level by high-throughput technologies. Independent proteomics studies have contributed significantly to further insight into adipocyte biology, particularly with respect to adipokine profiling. In this review novel findings obtained with adipo-proteomics studies are highlighted and the relevance of proteomics technologies to further understand molecular aspects of adipocyte biology is discussed.

Adipokines in reproductive function: a link between obesity and polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy associated with infertility and metabolic disorder in women of reproductive age. Dysfunction of adipose tissue has been implicated in the pathophysiology of PCOS. Increasing evidence shows that the dysregulated expression of adipokines, the secreted products of adipose tissue, plays an important role in the pathology of PCOS. Here, we review the role of several identified adipokines that may act as a link between obesity and PCOS. PCOS also reciprocally influences the profile of adipokines. Insight into the underlying mechanisms will help better understand the pathology of PCOS and identify new therapeutic targets of this syndrome.

Oxidative stress associated to dysfunctional adipose tissue: a potential link between obesity, type 2 diabetes mellitus and breast cancer

Diabetes mellitus and breast cancer are two important health problems. Type 2 diabetes (T2DM) and obesity are closely linked with both being associated with breast cancer. Despite abundant epidemiological data, there is no definitive evidence regarding the mechanisms responsible for this association. The proposed mechanisms by which diabetes affects breast cancer risk and prognosis are the same as the mechanisms hypothesised for the contribution of obesity to breast cancer risk. The obesity-induced inflammation promoted by adipose tissue dysfunction is a key feature, which is thought to be an important link between obesity and cancer. Inflammation induces an increase in free radicals and subsequently promotes oxidative stress, which may create a microenvironment favourable to the tumor development in obese persons. Oxidative stress is also proposed as the link between obesity and diabetes mellitus. Therefore, obesity-related oxidative stress could be a direct cause of neoplastic transformation associated with obesity and T2DM in breast cancer cells. This review is focused on the role of obesity-related oxidative stress in the context of chronic inflammation, on the time of breast cancer onset and progression, which provide targets for preventive and therapeutic strategies in the fields of diabetes and obesity-related breast cancer.

Interaction between resistin and adiponectin in the proliferation of rat vascular smooth muscle cells

We investigated the effect between resistin and adiponectin on the proliferation of vascular smooth muscle cells (VSMCs). We confirmed that resistin significantly increases the number of rat VSMCs as well as thymidine incorporation with them, whereas adiponectin diminishes resistin-induced cell proliferation. Resistin significantly increased p42/44 mitogen-activated protein kinase (MAPK) phosphorylation within rat VSMCs, whereas adiponectin inhibited resistin-induced MAPK phosphorylation. Moreover, resistin significantly increased c-fos expression, whereas adiponectin suppressed resistin-induced c-fos expression. Cell cycle progression is a tightly controlled event that is negatively regulated by cyclin-dependent kinases inhibitors (CDKIs) such as p53, p21, and p27. Resistin significantly decreased the expression of these CDKIs, whereas adiponectin restored the resistin-induced decrease in CDKIs expression. These effects were abolished in the MAPK inhibitors. In conclusion, resistin plays a role in the development of atherosclerosis, whereas adiponectin may be an important in its prevention in insulin-resistant patients.

Plasma resistin is associated with single nucleotide polymorphisms of a possible resistin receptor, the decorin gene, in the general Japanese population

Resistin is an adipokine secreted from adipocytes in mice. We previously reported that a single nucleotide polymorphism (SNP) -420 (rs1862513) in the human resistin gene (RETN), is correlated with plasma resistin. Decorin is a multifunctional proteoglycan, and its isoform, lacking 14 amino acids from the N terminal region of mature core decorin, recently was identified as a resistin receptor in mice. To examine whether SNPs in the vicinity of the human decorin gene (DCN) are associated with plasma resistin, we cross-sectionally analyzed six tag SNPs selected around DCN in the same linkage disequilibrium block in 2,078 community-dwelling Japanese subjects. Plasma resistin was associated with the rs7139228, rs7956537, rs516115, and rs3138167 genotypes in DCN. A multiple regression analysis revealed that the genotype of rs7308752 (G/G) or rs516115 (C/C) was associated with decreased plasma resistin after adjusted for age, sex, BMI, and the RETN SNP rs1862513. The effect of rs7139228 and rs1862513 seemed to be additive without synergistic interaction. Therefore, plasma resistin was associated with some tag SNPs around DCN in the general Japanese population. The possibility that human decorin is a human resistin receptor should be pursued.

Resistin - the link between adipose tissue dysfunction and insulin resistance in patients with obstructive sleep apnea

Background

Resistin is an adipocytokine, associated with obesity and inflammation. Its exact role in insulin resistance and diabetes in the general population is still controversial. The relation between resistin plasma levels, insulin resistance and risk of impaired glucose metabolism in OSA patients has not been investigated.

Materials and methods

Plasma levels of resistin were measured in 67 patients with OSA and impaired glucose metabolism. 34,7% (23/67) had diabetes; 40% (27/67) patients had impаired glucose tolerance(IGT); 25,3%(17/67) had normal glucose metabolism (NGM). The association between resistin, BMI, obesity, markers of insulin resistance, oxidative stress and sleep study characteristics was analysed. The different groups of patients were compared in regards to glucometabolic parameters and biomarkers of oxidative stress – isoprostanes and insulin resistance – free fatty acids (FFA).

Results

Plasma levels of resistin were higher in patients with diabetes (6,12 ±5,93ng/ml), compared to those with IGT (3,85±2,81ng/ml, p-0,021) and NGM (3,77±3,23, p-0,043). Resistin did not differ between patients with IGT and NGM (p-0,954). In OSA patients with BMI>40 resistin plasma levels correlated neither to the clinical parameters (BMI, IRI, HOMA-I, HbA1C, AHI, desaturation index), nor to the biomarkers of oxidative stress and insulin resistance. Free fatty acids (0,232>0,177mmol/l, p-0,037) were higher in diabetics in comparison to NGM.

Conclusions

Plasma resistin levels in OSA patients with BMI>40 are independent of insulin resistance and are not associated with the parameters, characterising the oxidative stress or severity of OSA. Resistin could be used in a multiple panel of clinical and biomarkers to discern patients with diabetes from those with IGT; in OSA patients with BMI >40 resistin together with HbA1C could discern patients with diabetes from those with NGM. In OSA patients with BMI >40 FFA and HbA1C are useful clinical markers in assessing the risk of dysglycaemia among patients with normal and IGT.

Resistin gene expression in visceral adipose tissue of postmenopausal women and its association with insulin resistance

AIM

The present study evaluates resistin mRNA expression in visceral adipose tissue (VAT) and its correlation with insulin resistance (homeostatic model assessment) in postmenopausal obese women.

MATERIALS & METHODS

A total of 68 (nonobese = 34 and obese = 34) age-matched (49-70 years) postmenopausal women were recruited for the study. Fasting blood samples were collected at admission and abdominal VAT were obtained during surgery for gall bladder stones or hysterectomy. Physical parameters (age, height, weight and BMI) were measured. Biochemical parameters (plasma insulin, plasma glucose and serum resistin) were estimated by enzymatic methods. The VAT resistin mRNA expression was evaluated by real-time PCR.

RESULTS

The relative mean (± standard deviation) VAT resistin mRNA expression in postmenopausal obese women lowered significantly by 20.4% compared with postmenopausal nonobese women (0.029 ± 0.011 vs 0.023 ± 0.013; p = 0.047). Furthermore, VAT resistin mRNA expression in postmenopausal obese women was downregulated by 0.69-fold when compared with age-matched postmenopausal nonobese women. Furthermore, the relative VAT resistin mRNA expression in postmenopausal obese women showed significant inverse association with insulin resistance (r = -0.48; p < 0.01) and serum resistin (r = -0.84; p < 0.001), while in postmenopausal nonobese women it did not show any association with both insulin resistance (r = 0.03; p > 0.05) and serum resistin (r = -0.03; p > 0.05).

CONCLUSION

The VAT resistin mRNA expression in postmenopausal obese women is associated to insulin resistance.

Dysregulated adipokines in the pathogenesis of type 2 diabetes and vascular disease

Obesity is commonly associated with type 2 diabetes and vascular disease. Changes in body composition in the obese state lead to a dysregulation of secretion of adipocyte-secreted hormones known as adipokines. Adipokines such as leptin and adiponectin are known to be involved in many physiological and pathological processes. Current knowledge suggests that adipokines provide potential therapeutic targets against type 2 diabetes and vascular disease.

Hyperbaric oxygen therapy improves peripheral insulin sensitivity in humans

AIM

Hyperbaric oxygen therapy is known to reduce fasting blood glucose in individuals with Type 2 diabetes. However, the mechanisms of this effect are not clear. The aim of this study was to determine whether peripheral insulin sensitivity by hyperinsulinaemic euglycaemic clamp is increased in patients presenting for hyperbaric oxygen therapy.

METHODS

Participants were non-obese individuals without Type 2 diabetes (n=5) or obese patients with Type 2 diabetes (n=5). Patients were given 100% oxygen at 2.0 absolute atmospheres for 2 h, six sessions per week for 5 weeks.

RESULTS

Peripheral insulin sensitivity was increased in the whole cohort (P=0.04). Subsequent analysis revealed that this was significant at both treatment 3 (+37.3 ± 12.7%, P=0.02) and treatment 30 (+40.6 ± 12.6%, P=0.009). HbA(1c) was significantly reduced in subjects without diabetes only (P<0.05).

CONCLUSION

Insulin sensitivity increased within 3 days of hyperbaric oxygen treatment and this was maintained for 30 sessions. This increase in insulin sensitivity is equivalent to that observed following moderate weight loss. The mechanisms underlying the insulin-sensitizing effect of hyperbaric oxygen require further elucidation.

Role of adipokines in atherosclerosis: interferences with cardiovascular complications in rheumatic diseases

Patients with rheumatic diseases have an increased risk of mortality by cardiovascular events. In fact, several rheumatic diseases such as rheumatoid arthritis, osteoarthritis, systemic lupus erythematosus, and ankylosing spondylitis are associated with a higher prevalence of cardiovascular diseases (CVDs). Although traditional cardiovascular risk factors have been involved in the pathogenesis of cardiovascular diseases in rheumatic patients, these alterations do not completely explain the enhanced cardiovascular risk in this population. Obesity and its pathologic alteration of fat mass and dysfunction, due to an altered pattern of secretion of proinflammatory adipokines, could be one of the links between cardiovascular and rheumatic diseases. Indeed, the incidence of CVDs is augmented in obese individuals with rheumatic disorders. Thus, in this paper we explore in detail the relationships among adipokines, rheumatic diseases, and cardiovascular complications by giving to the reader a holistic vision and several suggestions for future perspectives and potential clinical implications.

Over expression of resistin in adipose tissue of the obese induces insulin resistance

AIM: To compare resistin mRNA expression in subcutaneous adipose tissue (SAT) and its correlation with insulin resistance (IR) in postmenopausal obese women.

METHODS: A total of 68 postmenopausal women (non obese = 34 and obese = 34) were enrolled for the study. The women of the two groups were age matched (49-70 years). Fasting blood samples were collected at admission and abdominal SAT was obtained during surgery for gall bladder stones or hysterectomy. Physical parameters [age, height, weight, body mass index (BMI)] were measured. Biochemical (plasma insulin and plasma glucose) parameters were estimated by enzymatic methods. RNA was isolated by the Trizol method. SAT resistin mRNA expression was done by real time- reverse transcription polymerase chain reaction (RT-PCR) by using Quanti Tect SYBR Green RT-PCR master mix. Data was analyzed using independent Student’s t test, correlation and simple linear regression analysis.

RESULTS: The mean weight (52.81 ± 8.04 kg vs 79.56 ± 9.91 kg; P < 0.001), BMI (20.23 ± 3.05 kg/m²vs 32.19 ± 4.86 kg/m²; P < 0.001), insulin (8.47 ± 3.24 μU/mL vs 14.67 ± 2.18 μU/mL; P < 0.001), glucose (97.44 ± 11.31 mg/dL vs 109.67 ± 8.02 mg/dL; P < 0.001) and homeostasis model assessment index (2.01 ± 0.73 vs 3.96 ± 0.61; P < 0.001) were significantly higher in postmenopausal obese women compared to postmenopausal non obese women. The mean serum resistin level was also significantly higher in postmenopausal obese women compared to postmenopausal non obese women (9.05 ± 5.15 vs 13.92 ± 6.32, P < 0.001). Furthermore, the mean SAT resistin mRNA expression was also significantly (0.023 ± 0.008 vs 0.036 ± 0.009; P < 0.001) higher and over expressed 1.62 fold (up-regulated) in postmenopausal obese women compared to postmenopausal non obese women. In postmenopausal obese women, the relative SAT resistin mRNA expression showed positive (direct) and significant correlation with BMI (r = 0.78, P < 0.001) and serum resistin (r = 0.76, P < 0.001). Furthermore, the SAT resistin mRNA expression in postmenopausal obese women also showed significant and direct association (r = 0.45, P < 0.01) with IR, while in postmenopausal non obese women it did not show any association (r = -0.04, P > 0.05).

CONCLUSION: Increased SAT resistin mRNA expression probably leads to inducing insulin resistance and thus may be associated with obesity-related disorders in postmenopausal obese women.

Physiological, pathological and potential therapeutic roles of adipokines

Formerly regarded purely as passive energy storage, adipose tissue is now recognized as a vital endocrine organ. Adipocytes secrete diverse peptide hormones named adipokines, which act in a autocrine, paracrine or endocrine way to influence several biological functions. Adipokines comprise diverse bioactive substances, including cytokines, growth, and complement factors, which perform essential regulatory functions related to energy balance, satiety and immunity. Presently adipokines have been widely implicated in obesity, diabetes, hypertension and cardiovascular diseases. In this article we aim to present a brief description of the roles and potential therapeutic modulation of adipokines, such as leptin, resistin, adiponectin, apelin, visfatin, FABP-4, tumor necrosis factor-α (TNF-α), interleukin-6 and plasminogen activator inhibitor-1 (PAI-1).

Little evidence of systemic and adipose tissue inflammation in overweight individuals(†)

Context: The effect of weight loss by diet alone or diet in conjunction with exercise on low-grade inflammation in non-obese (overweight) individuals is not known. Objective: Test the hypothesis that 24 weeks of moderate calorie restriction (CR; 25%) by diet only or with aerobic exercise would reduce markers of systemic inflammation and attenuate inflammation gene expression in subcutaneous adipose tissue. Design: Randomized controlled trial. Setting: Institutional Research Center. Participants: Thirty-five overweight (body mass index: 27.8 ± 0.7 kg/m²) but otherwise healthy participants (16M/19F) completed the study. Intervention: Participants were randomized to either CR (25% reduction in energy intake, n = 12), caloric restriction + exercise (CR + EX: 12.5% reduction in energy intake + 12.5% increase in exercise energy expenditure, n = 12), or control (healthy weight-maintenance diet, n = 11) for 6 months. Main outcome measures: Fasting serum markers of inflammation [leptin, highly sensitive C-reactive protein (hsCRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), adiponectin] and inflammation-related genes [CD68, IL-6, TNF-α, macrophage migration inhibitory factor (MIF), monocyte chemoattractant protein-1 (MCP-1), adiponectin, plasminogen activator inhibitor-1 (PAI-1)] in subcutaneous adipose tissue. Results: CR and CR + EX lost similar amounts of body weight (–10 ± 1%), fat mass (–24 ± 3%), visceral fat (–27 ± 3%), and had increased insulin sensitivity (CR: 40 ± 20%, CR + EX: 66 ± 22%). Leptin was significantly decreased from baseline (p < 0.001) in both groups however TNF-α and IL-6 were not changed. hsCRP was decreased in CR + EX. There was no change in the expression of genes involved in macrophage infiltration (CD68, MIF MCP-1, PAI-1) or inflammation (IL-6, TNF-α, adiponectin) in either CR or CR + EX. Conclusion: A 10% weight loss with a 25% CR diet alone or with exercise did not impact markers of systemic inflammation or the expression of inflammation-related adipose genes in overweight individuals.

Association of resistin with metabolic syndrome in Indian subjects

BACKGROUND

The role of resistin in insulin sensitivity and metabolic syndrome has been controversial until now. Increased plasma/serum resistin levels are associated with metabolic syndrome and insulin resistance. The aim of this study was to investigate the relationship between serum resistin levels with markers of metabolic syndrome in males.

METHODS

A total of 386 male volunteers were enrolled in a case-control study. All of the enrolled volunteers were analyzed to confirm metabolic syndrome following the guidelines of National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) of 2001. Of the 386 volunteers, 192 were categorized as cases of metabolic syndrome, whereas 194 were registered as controls without metabolic syndrome. Volunteers enrolled in the study were analyzed for anthropometrical parameters, lipid profile status, insulin, insulin resistance, and resistin.

RESULTS

Higher levels of resistin were observed in cases when compared to controls (12.49 ± 4.73 ng/mL vs. 6.99 ± 1.98 ng/mL). Resistin was positively and significantly associated with serum triglyceride, cholesterol, and very-low-density lipoprotein, whereas it was negatively and significantly associated with serum high-density lipoprotein (HDL) levels. Multiple regression analysis of the data observed indicated that the triglyceride level was the major determinant for the development of metabolic syndrome in male samples.

CONCLUSION

This study demonstrates a positive correlation between resistin and factors of metabolic syndrome, except for HDL cholesterol (HDL-C), which was found to be negatively correlated in Indian male subjects. The study also found resistin to be a suitable peripheral blood marker.

Insulin resistance and bariatric surgery

The objective of this article is to systematically review the changes in insulin resistance after various types of bariatric surgical procedures. A Pubmed and EMBASE search for studies measuring insulin resistance before and after bariatric surgery was done and all original research articles from 1980 to present (2011) were included. Only the currently widely performed bariatric procedures were included. A meta-analysis of change in HOMA-IR was conducted, grouping studies with similar duration of follow-up. The percentage decrease in HOMA-IR at <=2 weeks, 1 month, 3 months, 6 months, 12 months and >16-18 months was found to be (mean ± standard error) -33.48 ± 5.78, -46.43 ± 6.99, -38.79 ± 9.64, -58.62 ± 7.38, -44.91 ± 7.98 and -67.04 ± 10.78%, respectively. RYGB (gastric bypass) and BPD (biliopancreatic diversion) produced a significant decrease in insulin resistance at 2 weeks after surgery, while LSG (sleeve gastrectomy) was strongly trending. LSG produced an earlier decrease in insulin resistance when compared to LAGB (gastric banding). RYGB, BPD and LSG produce an early decrease in insulin resistance through yet unknown mechanisms.

The role of resistin in colorectal cancer

BACKGROUND

To date the role of resistin in colorectal cancer (CRC) is far from being elucidated. The aim of this study was to investigate the association between serum resistin levels and CRC in relation to known risk/protective factors including anthropometric, metabolic, inflammatory parameters as well as lifestyle individual characteristics.

METHODS

40 CRC patients and 40 controls were enrolled. Body weight, height, waist circumference and blood pressure were recorded. Fasting plasma glucose, lipids, C-reactive protein (CRP) and resistin levels were measured. Metabolic Syndrome (MS) was defined according to the harmonized definition.

RESULTS

Resistin levels were significantly higher in CRC patients than in controls (p=0.028) and gradually increased with tumor stage progression (p=0.042). A high resistin level was statistically significant determinant of CRC after adjusting for age, sex, body mass index and lifestyle parameters (p=0.029). Resistin showed a strong association with CRP levels (p ≤ 0.0001). In stepwise regression analysis CRP remained the only independent predictor of both resistin levels (p=0.001) and CRC risk (p=0.021).

CONCLUSIONS

These results clarify the nature of the association between resistin and CRC risk suggesting that the proinflammatory state of cancer, rather than the clinical diagnosis of CRC itself or its link with obesity and MS, may govern this association.

Measurement of salivary resistin, visfatin and adiponectin levels

Hormonal determination in saliva offers several advantages. Peptides enter the salivary glands either by active transport mechanisms or are expressed and secreted by the salivary glands themselves. The collection of saliva is a noninvasive, easily repeatable and less stressful technique than blood withdrawal. The purpose of the present study was to introduce a method for measuring salivary resistin, visfatin and adiponectin levels and to evaluate their associations with serum levels. Resistin, visfatin and adiponectin levels were measured in serum and saliva of 50 healthy adult volunteers (17 male and 33 female) using commercial enzyme immunoassay kits for serum with minor modifications. The present study documented the determination of resistin and adiponectin levels in saliva and the significant correlation of salivary levels with serum levels (r=0.441, p<0.01 and r=0.347, p<0.05, respectively). Moreover, the identification of visfatin in saliva was achieved, but no significant correlation with serum visfatin levels was observed. To our knowledge, this is the first study to report the determination of resistin and visfatin in saliva and the significant correlation of salivary resistin with serum levels, while it confirmed the significant association between salivary and serum adiponectin. The introduction of salivary determinations of adipokines could contribute to the elucidation of the physiology and the role of the specific adipokines in various clinical conditions (obesity, insulin resistance, inflammation, reproduction, energy imbalance and stress response).

Association of circulating resistin with metabolic risk factors in Indian females having metabolic syndrome

Role of resistin in insulin sensitivity and metabolic syndrome (MetS) is controversial till date. Increased serum resistin levels are associated with MetS and insulin resistance. The aim of this study was to investigate the relationship between serum resistin levels with markers of the MetS in females. In a cross-sectional study, a total of 170 healthy female subjects were selected for the study. Out of which 71 (age 31.59 ± 4.88 years) were with MetS and 99 (age 31.75 ± 6.34 years) were without MetS. Different parameters of MetS and serum resistin level were measured according to the standard protocols as given in NCEP ATP III 2001 guideline. Serum resistin levels were significantly higher in subjects with MetS when compared with subjects without MetS [13.54 ± 4.14 ng/ml (n = 71) vs. 7.42 ± 2.31 ng/ml (n = 99); P ≤ 0.001]. Resistin levels were positively associated with waist circumference, systolic and diastolic blood pressure, plasma glucose, waist/hip ratio, serum triglycerides, serum cholesterol, serum VLDL, plasma insulin, and insulin resistance, while it was negatively associated with high-density lipoprotein. This study demonstrates a positive correlation between resistin and factors of MetS except high-density lipoprotein which was found to be negatively correlated in Indian female subjects.

Systemic resistin is increased in type 2 diabetic patients treated with loop diuretics

Increased serum resistin was found in rodent models of obesity and insulin resistance, whereas contradictory results have been obtained in human studies. In humans, resistin is primarily released by monocytes/macrophages, suggesting that soluble levels may be associated with macrophage activation. Here, systemic and monocyte-released resistin levels were found to be similar in type 2 diabetic (T2D) patients, overweight controls and normal-weight controls. When adjusted for body mass index and age, serum resistin modestly correlated with gamma-glutamyltransferase levels, fasting glucose and interleukin-6. Systemic resistin was marginally increased in T2D patients treated with beta-blockers or urate-lowering drugs and was considerably higher in patients treated with loop diuretics. Monocyte-released resistin was even reduced by the loop diuretic furosemide, excluding the possibility that this drug may directly stimulate resistin synthesis. In summary, the current data indicate that changes accompanying renal dysfunction but not obesity or type 2 diabetes are associated with increased serum resistin.

Insulin sensitivity in late gestation and early postpartum period: the role of circulating maternal adipokines

OBJECTIVE

Early postpartum period is characterised by a dramatic decrease in insulin resistance and significant metabolic alterations. The aims of this study were to determine the changes in circulating maternal concentrations of total adiponectin, adiponectin multimers, leptin and resistin before and after the delivery and to explore their relationship with insulin sensitivity.

METHODS

Twenty-seven normal pregnant women at term were included in this longitudinal study. Blood samples were taken before and 4 days after elective caesarean section. Total adiponectin, adiponectin multimers, leptin, resistin, glucose, insulin and prolactin were measured in maternal serum. Adiponectin multimers were measured before and after the delivery in eight women.

RESULTS

(1) The mean maternal serum total adiponectin concentration was significantly higher before than after delivery while the relative distribution of circulating maternal adiponectin multimers did not change after delivery; (2) the median maternal serum concentration of leptin was significantly higher in the antepartum than in the postpartum period; (3) the median maternal serum resistin concentration was comparable before and after delivery; (4) multiple linear regression analysis revealed that antepartum insulin sensitivity was associated with maternal low body mass index, and low glucose concentrations in glucose challenge test, as well as with maternal age and increased leptin concentrations. Postpartum insulin sensitivity was associated with decreased circulating resistin concentrations.

CONCLUSIONS

Despite increase in insulin sensitivity, early postpartum period is characterised by a decrease in maternal circulating total adiponectin and by steady concentrations of resistin and adiponectin multimers compared to the late third trimester.

Vascular biology of metabolic syndrome

The metabolic syndrome is a constellation of clinical risk factors comprising atherogenic dyslipidemia (low high-density lipoprotein and high triglycerides levels), elevated blood pressure, elevated plasma glucose, a prothrombotic state, and a proinflammatory state accompanied by an increased risk for cardiovascular disease and type 2 diabetes mellitus. The adipose tissue of obese humans contains increased numbers of macrophages, and once activated, these macrophages are responsible for the expression of most of the tissue's tumor necrosis factor (TNF)-α and interleukin (IL)-6. Chronic inflammation associated with visceral obesity induces altered lipoprotein metabolism and insulin resistance in the liver. Adipocytes secrete a variety of hormones, cytokines, growth factors, and other bioactive substances, conceptualized as adipocytokines, including plasminogen activator inhibitor 1 (PAI-1), TNF-α, leptin, and adiponectin. The dysregulation of these adipokines contributes to the pathogenesis of obesity. Adipose tissue-resident macrophages and adipocytes in the adipose tissue combined with the consequences of hyperglycemia, altered lipoproteins, and hyperinsulinemia in the vasculature and within organ microcirculation lead to dysfunctional endothelia and a proinflammatory state. Metabolic syndrome thus represents a combination of synergistic vascular pathologies that lead to an accelerated atherogenic state that compromises the ability of the patient to satisfactorily respond to humoral, cellular, and mechanical stresses.

Lipodystrophy and insulin resistance in combination antiretroviral treated HIV-1-infected patients: implication of resistin

BACKGROUND

Little information is available with respect to the involvement of resistin in lipodystrophy and metabolic disturbances in HIV-1-infected patients treated with combination antiretroviral therapy (cART). We determined whether the resistin (rest) -420C>G single-nucleotide polymorphism and plasma resistin are associated with the development of lipodystrophy and metabolic disturbances in HIV-1-infected patients treated with cART.

METHODS

The study group comprised 299 HIV-1-infected patients treated with a stable cART for at least 1 year (143 with lipodystrophy and 156 without) and 175 uninfected controls. Anthropometric, clinical, and metabolic variables were determined. Homeostasis model assessment for insulin resistance was used to evaluate insulin resistance. Plasma resistin levels were determined by enzyme-linked immunosorbent assay. The rest -420C>G was assessed using restriction fragment length polymorphism. Student t test, 1-way and 2-way analysis of variance, χ2 test, and Pearson and Spearman correlations were performed for statistical analysis.

RESULTS

Genotypes containing the rest -420G variant allele were significantly more common in HIV-1-infected patients without lipodystrophy compared with those with lipodystrophy (P = 0.037). Infected patients had significantly greater plasma resistin levels than uninfected controls (P < 0.001). Among infected patients, plasma resistin levels were significantly lower in patients with lipodystrophy with respect to those without (P = 0.034). In infected patients, plasma resistin levels had a significant positive correlation with insulin and homeostasis model assessment for insulin resistance: P < 0.001 and P = 0.002 in the lipodystrophy subset and P = 0.002 and P = 0.03 in the nonlipodystrophy subset, respectively.

CONCLUSIONS

In our cohort of white Spaniards, the rest -420C>G single-nucleotide polymorphism may be associated with cART-related lipodystrophy. Plasma resistin correlates with insulin resistance in infected patients with and without lipodystrophy.

Adipokines and psoriasis

Adipose tissue is an active endocrine organ contributing to the regulation of multiple metabolic pathways via self-produced bioactive products called adipokines. These adipokines are key players in the pathogenesis of metabolic syndrome and cardiovascular diseases. Co-occurrence of obesity and psoriasis could lead to interactions of both diseases in which adipokines, at least in part, are involved and may contribute to associated comorbidities of psoriasis. Until today numerous adipokines have been identified of which the most important ones are discussed in the following within the context of obesity, chronic inflammation and their possible role in the pathogenesis of psoriasis. Adipokines could serve as a missing link in the causal relationship between psoriasis and comorbidities and may provide a biomarker for disease severity, risk of comorbidities and treatment success.

Resistin, but not adiponectin and leptin, is associated with the risk of ischemic stroke among postmenopausal women: results from the Women's Health Initiative

BACKGROUND AND PURPOSE

Adipose tissue is considered an endocrine organ that secretes adipokines, which possibly mediate the effects of obesity on the risk of cardiovascular disease. However, there are yet limited prospective data on the association between circulating adipokine levels and the risk of ischemic stroke. We aimed to examine the associations of 3 adipokines (adiponectin, leptin, and resistin) with the risk of ischemic stroke.

METHODS

We conducted a prospective nested case-control study (972 stroke cases and 972 matched control subjects) within the Women's Health Initiative Observational Study cohort. The control subjects were matched to cases on age, race/ethnicity, date of study enrollment, and follow-up time.

RESULTS

Adipokine levels were associated with established stroke risk factors such as obesity and systolic blood pressure. Adjusted for body mass index, the ORs for incident ischemic stroke comparing the highest (Quartile 4) with the lowest quartile (Quartile 1) were 0.81 (95% CI, 0.61 to 1.08; P trend=0.068) for adiponectin, 1.15 (95% CI, 0.83 to 1.59; P trend=0.523) for leptin, and 1.57 (95% CI, 1.18 to 2.08; P trend=0.002) for resistin. The association for resistin remained significant even after accounting for established stroke risk factors (OR, 1.39; 95% CI, 1.01 to 1.90; P trend=0.036). Further adjustment for markers for inflammation, angiogenesis, and endothelial function also did not affect our results.

CONCLUSIONS

Circulating levels of resistin, but not those of adiponectin or leptin, are associated with an increased risk of incident ischemic stroke in postmenopausal women, independent of obesity and other cardiovascular disease risk factors.

Breast milk hormones and regulation of glucose homeostasis

Growing evidence suggests that a complex relationship exists between the central nervous system and peripheral organs involved in energy homeostasis. It consists in the balance between food intake and energy expenditure and includes the regulation of nutrient levels in storage organs, as well as in blood, in particular blood glucose. Therefore, food intake, energy expenditure, and glucose homeostasis are strictly connected to each other. Several hormones, such as leptin, adiponectin, resistin, and ghrelin, are involved in this complex regulation. These hormones play a role in the regulation of glucose metabolism and are involved in the development of obesity, diabetes, and metabolic syndrome. Recently, their presence in breast milk has been detected, suggesting that they may be involved in the regulation of growth in early infancy and could influence the programming of energy balance later in life. This paper focuses on hormones present in breast milk and their role in glucose homeostasis.

The metabolic syndrome: the crossroads between rheumatoid arthritis and cardiovascular risk

Rheumatoid arthritis (RA) patients have an incidence of cardiovascular (CV) diseases at least two times higher than the general population. Atherosclerosis, the main determinant of CV morbidity and mortality, and carotid intima-media thickness, an early preclinical marker of atherosclerosis, also occur early on in RA. Traditional CV risk factors seem to have the same prevalence in RA and non-RA patients, and thus do not fully explain the increased CV burden, suggesting that RA inflammation and therapies play a role in increasing CV risk in these patients. The metabolic syndrome and fat tissue are likely to be the major players in this complex network. The metabolic syndrome (MetS) represents a cluster of cardiovascular risk factors that have in common insulin resistance and increased visceral adiposity. This entity has received great attention in the last few years due to its contribution to the burden of cardiovascular morbidity and mortality. Moreover, recently the adipose tissue has emerged as a dynamic organ that releases several inflammatory and immune mediators (adipokines). The association of MetS and atherosclerosis is thought to be partly mediated by altered secretion of adipokines by the adipose tissue and, on the other hand, there are evidence that adipokines may play some role in inflammatory arthritides. Obesity is now regarded as a systemic, low-grade inflammatory state, and inflammation as a link between obesity, metabolic syndrome, and cardiovascular diseases. To obtain a full control of the CV risk, data suggest that it is therefore mandatory a "tight control" of both RA and MetS inflammations.

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.