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BackgroundObesity leads to adipocyte hypertrophy and adipokine dysregulation and is an independent risk factor for venous thromboembolism (VTE). However, the association between adipokines and VTE is not well established.ObjectivesTo examine whether adipokines are associated with increased risk of incident VTE.MethodsWe studied 1888 participants of the Multi-Ethnic Study of Atherosclerosis cohort who were initially free of VTE and had adipokine (adiponectin, leptin, and resistin) levels measured at either examination 2 or 3 (2002-2004 or 2004-2005, respectively). During follow-ups, VTE was ascertained through hospitalization records and death certificates by using ICD-9 and 10 codes. We used multivariable Cox proportional hazards regression to assess the association between 1 standard deviation (SD) log-transformed increments in adipokines and incident VTE.ResultsThe mean ± SD age was 64.7 ± 9.6 years, and 49.8% of participants were women. Medians (interquartile range) of adiponectin, leptin, and resistin were 17.3 (11.8-26.2) mcg/mL, 13.5 (5.6-28.2) ng/mL, and 15.0 (11.9-19.0) ng/mL, respectively. There were 78 incident cases of VTE after a median of 9.7 (5.0-12.4) years of follow-up. After adjusting for sociodemographics, smoking, and physical activity, the hazard ratios (95% CIs) per 1 SD increment of adiponectin, leptin, and resistin were 1.14 (0.90-1.44), 1.29 (1.00-1.66), and 1.38 (1.09-1.74), respectively. The association for resistin persisted after further adjustments for body mass index and computed tomography-derived total visceral adipose tissue area.ConclusionHigher resistin levels were independently associated with greater risk of incident VTE. Larger prospective cohort studies are warranted to confirm this association.

AimsResistin is a circulating inflammatory biomarker that is associated with cardiovascular disease. We investigated the associations of resistin and incident heart failure (HF) and its subtypes, as well as specific measures of subclinical HF (myocardial fibrosis and relevant biomarkers).MethodsWe analysed data from 1968 participants in the Multi-Ethnic Study of Atherosclerosis with measurements of plasma resistin levels at clinic visits from 2002 to 2005. Participants were subsequently followed for a median of 10.5 years for HF events. The associations between resistin levels and incident HF, HF with reduced ejection fraction (HFrEF), and HF with preserved ejection fraction (HFpEF) were examined using multivariable Cox proportional hazards models. Linear regression models assessed the associations between resistin levels and myocardial fibrosis from cardiac magnetic resonance imaging, as well as hs-cTnT and NT-proBNP.ResultsThe mean age of the cohort was 64.7 years, and 50.0% were female. Seventy-four participants (4%) developed incident HF during follow-up. In a Cox proportional hazards model adjusted for age, gender, education level, race/ethnicity, and traditional risk factors, higher resistin levels were significantly associated with incident HF (HR 1.44, CI 1.18-1.75, P = 0.001) and HFrEF (HR 1.47, CI 1.07-2.02, P = 0.016), but not with HFpEF (HR 1.25, CI 0.89-1.75, P = 0.195). Resistin levels showed no significant associations with myocardial fibrosis, NT-proBNP, or hs-cTnT levels.ConclusionsIn a multi-ethnic cohort free of cardiovascular disease at baseline, elevated resistin levels were associated with incident HF, more prominently with incident HFrEF than HFpEF, but not with subclinical myocardial fibrosis or biomarkers of HF.

Background: Multiparity is a risk factor for cardiovascular disease (CVD). However, the mechanisms of this relationship are unknown. Adipokines may predispose multiparous women to certain cardiometabolic complications that can increase their risk of future CVD. Materials and Methods: We studied 973 female participants of the Multi-Ethnic Study of Atherosclerosis free of CVD, who had complete data on parity and adipokines measured at Examination 2 or 3 (randomly assigned). Parity was categorized as nulliparity, 1-2, 3-4, and ≥5 live births. Multivariable linear regression was used to evaluate the association of parity with leptin, resistin, and adiponectin levels. Results: The women had mean age of 65 ± 9 years. After adjustment for age, race/ethnicity, study site, education, menopause status, smoking, physical activity, use of hormone therapy, and waist circumference, a history of grand multiparity (≥5 live births) was associated with 11% higher resistin levels (95% confidence interval [CI] 0-23) and 3-4 live births was associated with 23% higher leptin levels (95% CI 7-42), compared with nulliparity. After adjustment for computed tomography-measured visceral fat, the association of 3-4 live births with leptin remained significant. There were no significant associations of parity with adipokines after further adjustment for additional CVD risk factors. Multigravidity (but not parity) was inversely associated with adiponectin levels. Conclusions: In a multiethnic cohort of women, greater parity was associated with resistin and leptin; however, this association was attenuated after accounting for CVD risk factors. Dysregulation of adipokines could contribute to the excess CVD risk associated with multiparity. Further studies are needed to determine whether adipokines independently mediate the relationship between multiparity and CVD. Clinical trials registration: The MESA cohort is registered at NCT00005487.

BackgroundSepsis mortality has remained unchanged for greater than a decade, and early recognition continues to be the most important factor in mortality outcome. Plasma resistin concentration is increased in sepsis, but its mechanism and clinical relevance is unclear. As one function, resistin interacts with toll-like receptor 4 in competition with lipopolysaccharide, a main component of the gram-negative bacterial cell wall. It is not known if the type of infection leading to sepsis influences resistin production. The objective of this study was to investigate whether 1) early plasma resistin concentration can predict mortality, 2) elevated plasma resistin concentration is associated with clinical disease severity scores, such as SOFA, mSOFA and APACHE II, and 3) plasma resistin concentrations differ between gram negative versus other etiologies of sepsis.MethodsThis was an exploratory study in the framework of a prospective observational design. Peripheral venous blood samples were obtained from subjects admitted to the intensive care unit at clinical recognition of sepsis (0 hour) and at 6 and 24 hours. Vasopressor utilization was not a requirement for inclusion. Plasma was analyzed for resistin concentration by ELISA. Cytokine concentrations including IL-6, IL-8, and IL-10 were determined by cytokine bead array. Cytokine data were evaluated against publicly available sepsis RNA expression datasets to compare protein versus RNA expression levels in predicting clinical disease state. Clinical data were collected from electronic health records for clinical severity index calculations and context for interpretation of resistin and cytokine concentrations. Subjects were followed up to 60 days, or until death, whichever came first. Statistical analysis was completed with R package and SPSS software.ResultsResistin levels were elevated in subjects admitted to the intensive care unit with sepsis. Four-hundred subjects were screened with 45 subjects included in the final analysis. Thirteen of 45 patients were non-survivors. Mortality within 60 days correlated with significantly higher resistin concentrations than in survivors. A resistin concentration of >126 ng/mL at clinical recognition of sepsis and >197 ng/mL within the first 24 hours were associated with mortality within 60 days with an area under the curve of 0.82 and 0.88, respectively. Most subjects with resistin concentration greater than these threshold values were deceased prior to 30 days. Resistin concentrations correlated with SOFA, mSOFA, and APACHE II scores in addition to having association with increases in inflammatory and sepsis biomarkers. These associations were validated with analysis of RNA expression datasets.ConclusionPlasma resistin concentrations of >126 ng/mL at clinical recognition of sepsis and >197 ng/mL within the first 24 hours of clinical sepsis recognition are associated with all-cause mortality. Resistin concentration within this timeframe also has comparable mortality association to well-validated clinical severity indices of SOFA, mSOFA, and APACHE II scores.

BackgroundAdipokines have inflammatory and fibrotic properties that may be critical in interstitial lung disease (ILD). We examined associations of serum adipokine levels with CT imaging-based measures of subclinical ILD and lung function among community-dwelling adults.MethodsA subset of the original Multi-Ethnic Study of Atherosclerosis cohort (n = 1,968) had adiponectin, leptin, and resistin measured during follow-up visits (2002-2005). We used regression models to examine associations of adiponectin, leptin, and resistin levels with (1) high-attenuation areas (HAAs) from CT scans (2004-2005, n = 1,144), (2) interstitial lung abnormalities (ILAs) from CT scans (2010-2012, n = 872), and (3) FVC from spirometry (2004-2006, n = 1,446). We used -(1/HAA2), which we denoted with H, to model HAA as our outcome to meet model assumptions.ResultsHigher adiponectin was associated with lower HAA on CT imaging among adults with a BMI ≥ 25 kg/m2 (P for BMI interaction = .07). Leptin was more strongly associated with ILA among never smokers compared with ever smokers (P for smoking interaction = .004). For every 1-SD increment of log-transformed leptin, the percent predicted FVC was 3.8% lower (95% CI, -5.0 to -2.5). Higher serum resistin levels were associated with greater HAA on CT in a fully adjusted model. For every 1-SD increment of log-transformed resistin there was an increase in H of 14.8 (95% CI, 3.4-26.3).ConclusionsHigher adiponectin levels were associated with lower HAA on CT imaging among adults with a higher BMI. Higher leptin and resistin levels were associated with lower FVC and greater HAA, respectively.

ObjectiveResistin is a hormone that has been associated with metabolic syndrome and cardiovascular disease. The role of resistin in patients with peripheral artery disease (PAD) has not been fully explored. This study seeks to understand the relationship between serum resistin, vascular function, and cardiovascular outcomes in patients with PAD.MethodsThere were 106 patients with PAD who were recruited between 2011 and 2016. Patients attended a baseline visit during which a comprehensive vascular physiology assessment including medical and surgical history, radial artery tonometry, and flow mediated-vasodilation (FMD) was completed. A blood sample was drawn, and serum resistin was assayed using enzyme-linked immunosorbent assay kits. Using the time of study enrollment as the time of origin, incident major adverse cardiac events (MACEs) were identified by subsequent chart review and defined as a composite end point of myocardial infarction, coronary revascularization, transient ischemic attack, stroke, or death from a cardiac cause.ResultsPatients had a mean age of 68 ± 8 years, were largely white (75%), and had comorbidities commonly associated with PAD including hypertension (92%), hyperlipidemia (87%), coronary artery disease (37%), and diabetes mellitus (38%). After stratification by resistin quartile, higher resistin quartiles were significantly associated with an older age, a greater number of pack-years smoked, and a lower estimated glomerular filtration rate. Despite similar comorbidities and medication use, endothelial function, as measured by FMD, was significantly lower with increasing resistin quartile (I, 9.1% ± 3.3%; II, 7.1% ± 3.5%; III, 5.8% ± 4.0%; IV, 5.6% ± 3.5%; P = .002). In multivariable linear regression, higher resistin quartiles (III and IV) were associated with lower FMD relative to quartile I after adjusting for several patient characteristics, medications, and comorbidities (III, -2.26 [95% confidence interval (CI), -4.51 to -0.01; P = .05]; IV, -2.53 [95% CI, -4.87 to -0.20; P = .03]). During a median follow-up period of 36 months (interquartile range, 29-45 months), 21 patients experienced the primary end point. In a Cox proportional hazards model adjusted for smoking status, coronary artery disease, and age, each 1 ng/mL increase in resistin was associated with a 10% increased risk of MACEs (hazard ratio, 1.10; 95% CI, 1.00-1.20; P = .04).ConclusionsIn patients with PAD, higher levels of resistin were associated with impaired endothelial function and an increased rate of MACEs. These results suggest that resistin may be a marker or effector of impaired vascular physiology and adverse cardiac outcomes in patients with PAD. Further research is needed to determine the potential mechanisms by which resistin may impair endothelial function and increase MACEs in this population.

ObjectiveThis study examined the associations between abdominal IMAT area and density with inflammatory markers associated with cardiometabolic disease.Methods1897 participants enrolled in the Multi-Ethnic Study of Atherosclerosis underwent computed tomography to quantify body composition and measurements of adiponectin, leptin, interleukin-6 (IL-6), C-reactive protein (CRP), and resistin.ResultsThe mean age and body mass index of participants was 65years and 28kg/m2, respectively, and 50% were female. After adjustment for age, sex, and race/ethnicity, as IMAT area increased and density decreased from the first to fourth quartile, markers of inflammation increased linearly (p0.05).ConclusionsAbdominal IMAT area and density are associated with inflammatory markers, with these associations attenuated by central adiposity.

The Resistin-Like Molecules (RELM) α, β, and γ and their namesake, resistin, share structural and sequence homology but exhibit significant diversity in expression and function within their mammalian host. RELM proteins are expressed in a wide range of diseases, such as: microbial infections (eg. bacterial and helminth), inflammatory diseases (eg. asthma, fibrosis) and metabolic disorders (eg. diabetes). While the expression pattern and molecular regulation of RELM proteins are well characterized, much controversy remains over their proposed functions, with evidence of host-protective and pathogenic roles. Moreover, the receptors for RELM proteins are unclear, although three receptors for resistin, decorin, adenylyl cyclase-associated protein 1 (CAP1), and Toll-like Receptor 4 (TLR4) have recently been proposed. In this review, we will first summarize the molecular regulation of the RELM gene family, including transcription regulation and tissue expression in humans and mouse disease models. Second, we will outline the function and receptor-mediated signaling associated with RELM proteins. Finally, we will discuss recent studies suggesting that, despite early misconceptions that these proteins are pathogenic, RELM proteins have a more nuanced and potentially beneficial role for the host in certain disease settings.

PurposeSkeletal muscle is the largest regulator of glucose metabolism, but few population-based studies have examined the associations between muscle and inflammation. We studied the relationships between abdominal muscle area and density with selected adiposity-associated inflammatory mediators.MethodsNearly 2000 subjects underwent computed tomography of the abdomen and had venous fasting blood drawn concomitantly. The computed tomography scans were interrogated for visceral and subcutaneous fat, as well as abdominal lean muscle areas and densities. We then categorized the muscle into locomotion (psoas) and stabilization (rectus, obliques, and paraspinal) groups. Blood samples were assayed for interleukin-6 (IL-6), resistin, C-reactive protein, and TNF-α.ResultsThe mean age was 64.7 yr, and 49% were female. Forty percent were white, 26% Hispanic/Latino American, 21% African American, and 13% Chinese American. The mean body mass index was 28.0 kg·m, and 30% were obese (body mass index, >30 kg·m). Using multivariable linear regression models that included adjustment for abdominal muscle area, a 1-SD increment in the mean densities for total, stabilization, and locomotive abdominal muscle were each significantly associated with lower levels of IL-6 (β = -15%, -15%, and -9%, P < 0.01 for all) and resistin (β = -0.11, -0.11, and -0.07 ng·mL, P < 0.02 for all), but not C-reactive protein or TNF-α. Conversely, muscle area was not independently associated with any of the inflammatory mediators studied.ConclusionsHigher densities of several muscle groups in the abdomen are significantly associated with lower IL-6 and resistin levels, independent of the muscle area in these groups. Techniques that enhance muscle density may reduce levels of adiposity-associated inflammatory mediators.

Intervertebral disc degeneration (IDD) is an important cause of low back pain. Recent evidence suggests that in addition to abnormal and excessive mechanical loading, inflammation may be a key driver for both IDD and low back pain. Obesity, a known mechanical risk factor of IDD, is now increasingly being recognized as a systemic inflammatory state with adipokines being postulated as likely inflammatory mediators. The aim of this review was to summarize the current literature regarding the inflammatory role of adipokines in the pathophysiology of IDD. A systematic literature search was performed using the OVID Medline, EMBASE and PubMed databases to identify all studies assessing IDD and adipokines. Fifteen studies were included in the present review. Leptin was the most commonly assessed adipokine. Ten of 15 studies were conducted in humans; three in rats and two in both humans and rats. Studies focused on a variety of topics ranging from receptor identification, pathway analysis, genetic associations, and proteonomics. Currently, data from both human and animal experiments demonstrate significant effects of leptin and adiponectin on the internal milieu of intervertebral discs. However, future studies are needed to determine the molecular pathway relationships between adipokines in the pathophysiology of IDD as avenues for future therapeutic targets.

Helminths trigger multiple immunomodulatory pathways that can protect from sepsis. Human resistin (hRetn) is an immune cell-derived protein that is highly elevated in helminth infection and sepsis. However, the function of hRetn in sepsis, or whether hRetn influences helminth protection against sepsis, is unknown. Employing hRetn-expressing transgenic mice (hRETNTg+) and recombinant hRetn, we identify a therapeutic function for hRetn in lipopolysaccharide (LPS)-induced septic shock. hRetn promoted helminth-induced immunomodulation, with increased survival of Nippostrongylus brasiliensis (Nb)-infected hRETNTg+ mice after a fatal LPS dose compared with naive mice or Nb-infected hRETNTg- mice. Employing immunoprecipitation assays, hRETNTg+Tlr4-/- mice, and human immune cell culture, we demonstrate that hRetn binds the LPS receptor Toll-like receptor 4 (TLR4) through its N terminal and modulates STAT3 and TBK1 signaling, triggering a switch from proinflammatory to anti-inflammatory responses. Further, we generate hRetn N-terminal peptides that are able to block LPS proinflammatory function. Together, our studies identify a critical role for hRetn in blocking LPS function with important clinical significance in helminth-induced immunomodulation and sepsis.

PurposePhysical activity is associated with decreased adiposity-related inflammation in adults. Whether this association is independent of central obesity is unknown but important for understanding the mechanisms associated with reducing cardiometabolic disease risk through physical activity. This study examined whether associations of physical activity and obesity-related inflammatory markers were independent of central adiposity.MethodsBetween 2002 and 2005, 1970 participants from the Multi-Ethnic Study of Atherosclerosis completed detailed health history and physical activity questionnaires, underwent physical measurements including computed tomography to quantify abdominal visceral and subcutaneous fat, and measurements of adiponectin, leptin, interleukin-6, tumor necrosis factor-alpha, and resistin. Statistical analyses included analysis of covariance and multivariable-adjusted regression.ResultsThe mean (range) age of participants was 64.7 (55-84) yr and 50% were women. After adjustment for age and sex, and compared with the lowest quartile, inflammatory markers in the highest quartile of moderate-to-vigorous physical activity were 16% higher for adiponectin and 30%, 26%, and 9% lower for leptin, interleukin-6, and resistin, respectively (P < 0.05 for all). In linear regression adjusted for demographics, dyslipidemia, hypertension, diabetes, smoking, glomerular filtration rate, renin, and aldosterone, each standard deviation increment of moderate-to-vigorous physical activity was associated with significantly higher levels of adiponectin (β = 0.04) and lower levels of leptin (β = -0.06), interleukin-6 (β = -0.08), and resistin (β = -0.05, P < 0.05 for all). The associations with leptin, interleukin-6, and resistin were independent of total and central adiposity (P < 0.05), whereas the association between moderate-to-vigorous physical activity and adiponectin was attenuated by central adiposity (P > 0.05). There were no significant interactions by race/ethnicity or sex.ConclusionsModerate-to-vigorous physical activity was associated with a more favorable profile of inflammatory markers, independent of relevant cardiometabolic disease risk factors including central obesity.

In the last two decades, perceptions about the role of body fat have changed. Adipocytes modulate endocrine and immune homeostasis by synthesizing hundreds of hormones, known as adipocytokines. Many studies have been investigating the influences and effects of these adipocytokines and suggest that they are modulated by the nutritional and immunologic milieu. Kidney transplant recipients (KTRs) are a unique and relevant population in which the function of adipocytokines can be examined, given their altered nutritional and immune status and subsequent dysregulation of adipocytokine metabolism. In this review, we summarize the recent findings about four specific adipocytokines and their respective roles in KTRs. We decided to evaluate the most widely described adipocytokines, including leptin, adiponectin, visfatin and resistin. Increasing evidence suggests that these adipocytokines may lead to cardiovascular events and metabolic changes in the general population and may also increase mortality and graft loss rate in KTRs. In addition, we present findings on the interrelationship between serum adipocytokine levels and nutritional and immunologic status, and mechanisms by which adipocytokines modulate morbidity and outcomes in KTRs.

In the last two decades, perceptions about the role of body fat have changed. Adipocytes modulate endocrine and immune homeostasis by synthesizing hundreds of hormones, known as adipocytokines. Many studies have been investigating the influences and effects of these adipocytokines and suggest that they are modulated by the nutritional and immunologic milieu. Kidney transplant recipients (KTRs) are a unique and relevant population in which the function of adipocytokines can be examined, given their altered nutritional and immune status and subsequent dysregulation of adipocytokine metabolism. In this review, we summarize the recent findings about four specific adipocytokines and their respective roles in KTRs. We decided to evaluate the most widely described adipocytokines, including leptin, adiponectin, visfatin and resistin. Increasing evidence suggests that these adipocytokines may lead to cardiovascular events and metabolic changes in the general population and may also increase mortality and graft loss rate in KTRs. In addition, we present findings on the interrelationship between serum adipocytokine levels and nutritional and immunologic status, and mechanisms by which adipocytokines modulate morbidity and outcomes in KTRs.

Resistin is an adipocytokine that is associated with inflammation, coronary artery disease, and other types of cardiovascular disease among patients with normal kidney function. However, little is known about the association of resistin with outcomes in kidney transplant recipients. We collected socio-demographic and clinical parameters, medical and transplant history, and laboratory data from 988 prevalent kidney transplant recipients enrolled in the Malnutrition-Inflammation in Transplant-Hungary Study (MINIT-HU study). Serum resistin levels were measured at baseline. Associations between serum resistin level and death with a functioning graft over a 6-year follow-up period were examined in unadjusted and adjusted models. The mean±SD age of the study population was 51 ± 13 years, among whom 57% were men and 21% were diabetics. Median serum resistin concentrations were significantly higher in patients who died with a functioning graft as compared to those who did not die during the follow-up period (median [IQR]: 22[15-26] vs. 19[14-22] ng/ml, respectively; P < 0.001). Higher serum resistin level was associated with higher mortality risk in both unadjusted and fully adjusted models: HRs (95% CI): 1.33(1.16-1.54) and 1.21(1.01-1.46), respectively. In prevalent kidney transplant recipients, serum resistin was an independent predictor of death with a functioning graft.

Resistin is an adipocytokine that is associated with inflammation, coronary artery disease, and other types of cardiovascular disease among patients with normal kidney function. However, little is known about the association of resistin with outcomes in kidney transplant recipients. We collected socio-demographic and clinical parameters, medical and transplant history, and laboratory data from 988 prevalent kidney transplant recipients enrolled in the Malnutrition-Inflammation in Transplant-Hungary Study (MINIT-HU study). Serum resistin levels were measured at baseline. Associations between serum resistin level and death with a functioning graft over a 6-year follow-up period were examined in unadjusted and adjusted models. The mean±SD age of the study population was 51 ± 13 years, among whom 57% were men and 21% were diabetics. Median serum resistin concentrations were significantly higher in patients who died with a functioning graft as compared to those who did not die during the follow-up period (median [IQR]: 22[15-26] vs. 19[14-22] ng/ml, respectively; P < 0.001). Higher serum resistin level was associated with higher mortality risk in both unadjusted and fully adjusted models: HRs (95% CI): 1.33(1.16-1.54) and 1.21(1.01-1.46), respectively. In prevalent kidney transplant recipients, serum resistin was an independent predictor of death with a functioning graft.

ObjectiveProspective data on the association between resistin levels and cardiovascular disease (CVD) events are sparse with conflicting results.MethodsWe studied 3044 aged 70-79 years from the Health, Aging, and Body Composition Study. CVD events were defined as coronary heart disease (CHD) or stroke events. «Hard » CHD events were defined as CHD death or myocardial infarction. We estimated hazard ratio (HR) and 95% confidence intervals (CI) according to the quartiles of serum resistin concentrations and adjusted for clinical variables, and then further adjusted for metabolic disease (body mass index, fasting plasma glucose, abdominal visceral and subcutaneous adipose tissue, leptin, adiponectin, insulin) and inflammation (C-reactive protein, interleukin-6, tumor necrosis factors-α).ResultsDuring a median follow-up of 10.1 years, 559 patients had « hard » CHD events, 884 CHD events and 1106 CVD Events. Unadjusted incidence rate for CVD events was 36.6 (95% CI 32.1-41.1) per 1000 persons-year in the lowest quartile and 54.0 per 1000 persons-year in the highest quartile (95% CI 48.2-59.8, P for trend < 0.001). In the multivariate models adjusted for clinical variables, HRs for the highest vs. lowest quartile of resistin was 1.52 (95% CI 1.20-1.93, P < 0.001) for « Hard » CHD events, 1.41 (95% CI 1.16-1.70, P = 0.001) for CHD events and 1.35 (95% CI 1.14-1.59, P = 0.002) for CVD events. Further adjustment for metabolic disease slightly reduced the associations while adjustment for inflammation markedly reduced the associations.ConclusionsIn older adults, higher resistin levels are associated with CVD events independently of clinical risk factors and metabolic disease markers, but markedly attenuated by inflammation.

The neuroendocrine effects of leptin on metabolism hold promise to be translated into a complementary therapy to traditional insulin therapy for diabetes and obesity. However, injections of leptin can provoke inflammation. We tested the effects of leptin, produced in the physiological adipocyte location, on metabolism in mouse models of genetic and dietary obesity. We generated 3T3-L1 adipocytes constitutively secreting leptin and encapsulated them in a poly-L-lysine membrane, which protects the cells from immune rejection. Ob/ob mice (OB) were injected with capsules containing no cells (empty, OB[Emp]), adipocytes (OB[3T3]), or adipocytes overexpressing leptin (OB[Lep]) into both visceral fat depots. Leptin was found in the plasma of OB[Lep], but not OB[Emp] and OB[3T3] mice at the end of treatment (72 days). The OB[Lep] and OB[3T3] mice have transiently suppressed appetite and weight loss compared to OB[Emp]. Only OB[Lep] mice have greater brown fat mass, metabolic rate, and reduced resistin plasma levels compared to OB[Emp]. Glucose tolerance was markedly better in OB[Lep] vs. OB[Emp] and OB[3T3] mice as well as in wild type mice with high-fat diet-induced obesity and insulin resistance treated with encapsulated leptin-producing adipocytes. Our proof-of-principle study provides evidence of long-term improvement of glucose tolerance with encapsulated adipocytes producing leptin.

The neuroendocrine effects of leptin on metabolism hold promise to be translated into a complementary therapy to traditional insulin therapy for diabetes and obesity. However, injections of leptin can provoke inflammation. We tested the effects of leptin, produced in the physiological adipocyte location, on metabolism in mouse models of genetic and dietary obesity. We generated 3T3-L1 adipocytes constitutively secreting leptin and encapsulated them in a poly-L-lysine membrane, which protects the cells from immune rejection. Ob/ob mice (OB) were injected with capsules containing no cells (empty, OB[Emp]), adipocytes (OB[3T3]), or adipocytes overexpressing leptin (OB[Lep]) into both visceral fat depots. Leptin was found in the plasma of OB[Lep], but not OB[Emp] and OB[3T3] mice at the end of treatment (72 days). The OB[Lep] and OB[3T3] mice have transiently suppressed appetite and weight loss compared to OB[Emp]. Only OB[Lep] mice have greater brown fat mass, metabolic rate, and reduced resistin plasma levels compared to OB[Emp]. Glucose tolerance was markedly better in OB[Lep] vs. OB[Emp] and OB[3T3] mice as well as in wild type mice with high-fat diet-induced obesity and insulin resistance treated with encapsulated leptin-producing adipocytes. Our proof-of-principle study provides evidence of long-term improvement of glucose tolerance with encapsulated adipocytes producing leptin.

ScopeThis study evaluated the capacity of dietary catechin (C), quercetin (Q), and the combination of both (CQ), to attenuate adipose inflammation triggered by high fructose (HFr) consumption in rats and by tumor necrosis factor alpha (TNF-α) in 3T3-L1 adipocytes.Methods and resultsIn rats, HFr consumption for 6 wk caused dyslipidemia, insulin resistance, reduced plasma adiponectin, adiposity, and adipose tissue inflammation. Dietary supplementation with 20 mg/kg/day of C, Q, and CQ improved all these parameters. In 3T3-L1 adipocytes, C and Q attenuated TNF-α-induced elevated protein carbonyls, increased proinflammatory cytokine expression (MCP-1, resistin), and decreased adiponectin. The protective effects of C and Q on adipose inflammation are in part associated with their capacity to (i) decrease the activation of the mitogen-activated kinases (MAPKs) JNK and p38; and (ii) prevent the downregulation of PPAR-γ. In summary, C and Q, and to a larger extent the combination of both, attenuated adipose proinflammatory signaling cascades and regulated the balance of molecules that improve (adiponectin) or impair (TNF-α, MCP-1, resistin) insulin sensitivity.ConclusionTogether, these findings suggest that dietary Q and C may have potential benefits in mitigating MetS-associated adipose inflammation, oxidative stress, and insulin resistance.

Catecholamines and adipokines function as hormones; catecholamines as neurotransmitters in the sympathetic nervous system, and adipokines as mediators of metabolic processes. It has become increasingly clear, however, that both also function as immunomodulators of innate and adaptive immune cells, including macrophages. Macrophages can respond to, as well as produce their own catecholamines. Dopamine, noradrenaline, and adrenaline are the most abundant catecholamines in the body, and can induce both pro-inflammatory and anti-inflammatory immune responses in macrophages, as well as non-immune processes such as thermogenesis. Though they are responsive to adipokines, particularly lipoproteins, leptin, and adiponectin, macrophages generally do not synthesize their own adipokines, with the exception being resistin-like molecules. Adipokines contribute to adverse metabolic and immune responses by stimulating lipid accumulation, foam cell formation and pro-inflammatory cytokine production in macrophages. Adipokines can also promote balance or resolution during metabolic and immune processes by promoting reverse lipid transport and expression of Th2 cytokines. This review will explore the mechanisms by which catecholamines and adipokines influence macrophage function in neural pathways, immunity and metabolism.

ObjectiveTo describe the relationship between circulating resistin levels and cardiovascular diseases (CVD) and all-cause death in a multi-ethnic cohort.Methods and resultsWe studied 1913 participants from the Multi-Ethnic Study of Atherosclerosis with measurements of plasma resistin levels. Absolute proportions experiencing new-onset atrial fibrillation (AF), atherosclerotic CVD (myocardial infarction, angina, resuscitated cardiac arrest, stroke), heart failure (HF), and all-cause death were calculated for each quartile of resistin. We used adjusted Cox proportional regression modeling resistin as a continuous variable per standard deviation of log-transformed resistin and secondarily as a categorical variable using resistin quartiles. Results were stratified by sex and race/ethnicity. The mean age of the population was 64.5 ± 10 years with half being female and a median resistin concentration of 15.1 ng/mL (11.9-19.1). Mean follow-up time was 7.2 ± 1.8 years. There was a graded increase in the occurrence of all outcomes across increasing quartiles of resistin. Modeled as a continuous variable, after adjustment for anthropomorphic measures, traditional risk factors, markers of inflammation, and other adipokines, significant associations were noted for HF (HR 1.4, CI 1.0-2.0), hard and all CVD (HR 1.3, 1.1-1.7 and 1.3, 1.1-1.6, respectively), and CHD (HR 1.31, 1.0-1.6), but not for AF or death. Significant interaction terms were noted between resistin and race, with Hispanic race/ethnicity showing the strongest relationship between resistin and outcomes.ConclusionsIn an ethnically diverse population without known CVD at baseline, there was a strong, independent association between higher resistin levels and incident CVD, CHD and HF.

Parasitic helminth infections can be associated with lifelong morbidity such as immune-mediated organ failure. A better understanding of the host immune response to helminths could provide new avenues to promote parasite clearance and/or alleviate infection-associated morbidity. Murine resistin-like molecules (RELM) exhibit pleiotropic functions following helminth infection including modulating the host immune response; however, the relevance of human RELM proteins in helminth infection is unknown. To examine the function of human resistin (hResistin), we utilized transgenic mice expressing the human resistin gene (hRetnTg+). Following infection with the helminth Nippostrongylus brasiliensis (Nb), hResistin expression was significantly upregulated in infected tissue. Compared to control hRetnTg- mice, hRetnTg+ mice suffered from exacerbated Nb-induced inflammation characterized by weight loss and increased infiltration of inflammatory monocytes in the lung, along with elevated Nb egg burdens and delayed parasite expulsion. Genome-wide transcriptional profiling of the infected tissue revealed that hResistin promoted expression of proinflammatory cytokines and genes downstream of toll-like receptor signaling. Moreover, hResistin preferentially bound lung monocytes, and exogenous treatment of mice with recombinant hResistin promoted monocyte recruitment and proinflammatory cytokine expression. In human studies, increased serum resistin was associated with higher parasite load in individuals infected with soil-transmitted helminths or filarial nematode Wuchereria bancrofti, and was positively correlated with proinflammatory cytokines. Together, these studies identify human resistin as a detrimental factor induced by multiple helminth infections, where it promotes proinflammatory cytokines and impedes parasite clearance. Targeting the resistin/proinflammatory cytokine immune axis may provide new diagnostic or treatment strategies for helminth infection and associated immune-mediated pathology.

ObjectiveObesity is associated with changes in both right (RV) and left (LV) ventricular morphology, but the biological basis of this finding is not well established. We examined whether adipokine levels were associated with RV morphology and function in a population-based multiethnic sample free of clinical cardiovascular disease.MethodsWe examined relationships of leptin, resistin, TNF-α, and adiponectin with RV morphology and function (from cardiac MRI) in participants (n = 1,267) free of clinical cardiovascular disease from the Multi-Ethnic Study of Atherosclerosis (MESA)-RV study. Multivariable regressions (linear, quantile [25th and 75th] and generalized additive models [GAM]) were used to examine the independent association of each adipokine with RV mass, RV end-diastolic volume (RVEDV), RV end-systolic volume (RVESV), RV stroke volume (RVSV) and RV ejection fraction (RVEF).ResultsHigher leptin levels were associated with significantly lower levels of RV mass, RVEDV, RVESV and stroke volume, but not RVEF, after adjustment for age, gender, race, height and weight. These associations were somewhat attenuated but still significant after adjustment for traditional risk factors and covariates, and were completely attenuated when correcting for the respective LV measures. There were no significant interactions of age, gender, or race/ethnicity on the relationship between the four adipokines and RV structure or function.ConclusionsLeptin levels are associated with favorable RV morphology in a multi-ethnic population free of cardiovascular disease, however these associations may be explained by a yet to be understood bi-ventricular process as this association was no longer present after adjustment for LV values. These findings complement the associations previously shown between adipokines and LV structure and function in both healthy and diseased patients. The mechanisms linking adipokines to healthy cardiovascular function require further investigation.

Parasitic helminth infections can be associated with lifelong morbidity such as immune-mediated organ failure. A better understanding of the host immune response to helminths could provide new avenues to promote parasite clearance and/or alleviate infection-associated morbidity. Murine resistin-like molecules (RELM) exhibit pleiotropic functions following helminth infection including modulating the host immune response; however, the relevance of human RELM proteins in helminth infection is unknown. To examine the function of human resistin (hResistin), we utilized transgenic mice expressing the human resistin gene (hRetnTg+). Following infection with the helminth Nippostrongylus brasiliensis (Nb), hResistin expression was significantly upregulated in infected tissue. Compared to control hRetnTg- mice, hRetnTg+ mice suffered from exacerbated Nb-induced inflammation characterized by weight loss and increased infiltration of inflammatory monocytes in the lung, along with elevated Nb egg burdens and delayed parasite expulsion. Genome-wide transcriptional profiling of the infected tissue revealed that hResistin promoted expression of proinflammatory cytokines and genes downstream of toll-like receptor signaling. Moreover, hResistin preferentially bound lung monocytes, and exogenous treatment of mice with recombinant hResistin promoted monocyte recruitment and proinflammatory cytokine expression. In human studies, increased serum resistin was associated with higher parasite load in individuals infected with soil-transmitted helminths or filarial nematode Wuchereria bancrofti, and was positively correlated with proinflammatory cytokines. Together, these studies identify human resistin as a detrimental factor induced by multiple helminth infections, where it promotes proinflammatory cytokines and impedes parasite clearance. Targeting the resistin/proinflammatory cytokine immune axis may provide new diagnostic or treatment strategies for helminth infection and associated immune-mediated pathology.

ObjectiveObesity is associated with changes in both right (RV) and left (LV) ventricular morphology, but the biological basis of this finding is not well established. We examined whether adipokine levels were associated with RV morphology and function in a population-based multiethnic sample free of clinical cardiovascular disease.MethodsWe examined relationships of leptin, resistin, TNF-α, and adiponectin with RV morphology and function (from cardiac MRI) in participants (n = 1,267) free of clinical cardiovascular disease from the Multi-Ethnic Study of Atherosclerosis (MESA)-RV study. Multivariable regressions (linear, quantile [25th and 75th] and generalized additive models [GAM]) were used to examine the independent association of each adipokine with RV mass, RV end-diastolic volume (RVEDV), RV end-systolic volume (RVESV), RV stroke volume (RVSV) and RV ejection fraction (RVEF).ResultsHigher leptin levels were associated with significantly lower levels of RV mass, RVEDV, RVESV and stroke volume, but not RVEF, after adjustment for age, gender, race, height and weight. These associations were somewhat attenuated but still significant after adjustment for traditional risk factors and covariates, and were completely attenuated when correcting for the respective LV measures. There were no significant interactions of age, gender, or race/ethnicity on the relationship between the four adipokines and RV structure or function.ConclusionsLeptin levels are associated with favorable RV morphology in a multi-ethnic population free of cardiovascular disease, however these associations may be explained by a yet to be understood bi-ventricular process as this association was no longer present after adjustment for LV values. These findings complement the associations previously shown between adipokines and LV structure and function in both healthy and diseased patients. The mechanisms linking adipokines to healthy cardiovascular function require further investigation.

ObjectiveNearly, a third of obese individuals, termed metabolically benign obese, have a low burden of adiposity-related cardiometabolic abnormalities, whereas a substantial proportion of normal-weight individuals possess risk factors.MethodsIn cross-sectional analyses of 699 normal weight and 1,294 overweight/obese postmenopausal women enrolled in a nested case-control stroke study ancillary to the Women's Health Initiative Observational Study, we compared levels of adiponectin, leptin, and resistin among metabolically benign normal weight, at-risk normal weight, metabolically benign obese, and at-risk obese women using components of the ATP III definition of the metabolic syndrome (metabolically benign: ≤1 of the four components; at-risk phenotype: ≥2 components or diabetes).ResultsOverall, 382/699 normal-weight women (54.6%) and 328/1,194 overweight/obese women (27.5%) were metabolically benign. Among normal-weight women, at-risk women had higher leptin and lower adiponectin levels compared to metabolically benign women; multivariate-adjusted odds ratios were significant for having leptin (OR: 2.51; 95% CI: 1.28-5.01) and resistin (1.46; 1.03-2.07) in the top tertile and adiponectin in the bottom tertile (2.64; 1.81-3.84). Compared to metabolically benign overweight/obese women, at-risk obese women had higher odds of having leptin in the top tertile (1.62; 1.24-2.12) and adiponectin in the bottom tertile (2.78; 2.04-3.77).ConclusionsOverall, metabolically benign overweight/obese women had an intermediate adipokine profile (between at-risk obese and metabolically benign normal-weight women), whereas at-risk normal-weight women had a less favorable profile compared to metabolically benign normal-weight women. As adiponectin was the only adipokine independent of BMI, it may be most likely to have a role in the etiological pathway of these phenotypes.

Adipokines are secreted from adipose tissue, influence energy homeostasis and may contribute to the association between obesity and hypertension. Among 1897 participants enrolled in the Multi-Ethnic Study of Atherosclerosis, we examined associations between blood pressure and leptin, tumor necrosis factor-α (TNFα), resistin and total adiponectin. The mean age and body mass index (BMI) was 64.7 years and 28.1, respectively, and 50% were female. After adjustment for risk factors, a 1-s.d.-increment higher leptin level was significantly associated with higher systolic (5.0 mm Hg), diastolic (1.9), mean arterial (2.8) and pulse pressures (3.6), as well as a 34% higher odds for being hypertensive (P

Adipokines are secreted from adipose tissue, influence energy homeostasis and may contribute to the association between obesity and hypertension. Among 1897 participants enrolled in the Multi-Ethnic Study of Atherosclerosis, we examined associations between blood pressure and leptin, tumor necrosis factor-α (TNFα), resistin and total adiponectin. The mean age and body mass index (BMI) was 64.7 years and 28.1, respectively, and 50% were female. After adjustment for risk factors, a 1-s.d.-increment higher leptin level was significantly associated with higher systolic (5.0 mm Hg), diastolic (1.9), mean arterial (2.8) and pulse pressures (3.6), as well as a 34% higher odds for being hypertensive (P

Resistin is a polypeptide hormone that was reported to be associated with insulin resistance, inflammation and risk of type 2 diabetes and cardiovascular disease. We conducted a genome-wide association (GWA) study on circulating resistin levels in individuals of European ancestry drawn from the two independent studies: the Nurses' Health Study (n = 1590) and the Health, Aging and Body Composition Study (n = 1658). Single-nucleotide polymorphisms (SNPs) identified in the GWA analysis were replicated in an independent cohort of Europeans: the Gargano Family Study (n = 659). We confirmed the association with a previously known locus, the RETN gene (19p13.2), and identified two novel loci near the TYW3/CRYZ gene (1p31) and the NDST4 gene (4q25), associated with resistin levels at a genome-wide significant level, best represented by SNP rs3931020 (P = 6.37 × 10(-12)) and SNP rs13144478 (P = 6.19 × 10(-18)), respectively. Gene expression quantitative trait loci analyses showed a significant cis association between the SNP rs3931020 and CRYZ gene expression levels (P = 3.68 × 10(-7)). We also found that both of these two SNPs were significantly associated with resistin gene (RETN) mRNA levels in white blood cells from 68 subjects with type 2 diabetes (both P = 0.02). In addition, the resistin-rising allele of the TYW3/CRYZ SNP rs3931020, but not the NDST4 SNP rs13144478, showed a consistent association with increased coronary heart disease risk [odds ratio = 1.18 (95% CI, 1.03-1.34); P = 0.01]. Our results suggest that genetic variants in TYW3/CRYZ and NDST4 loci may be involved in the regulation of circulating resistin levels. More studies are needed to verify the associations of the SNP rs13144478 with NDST4 gene expression and resistin-related disease.

Exposure to traumatic psychological stress increases risk for disease events and mortality in patients with cardiovascular disease (CVD). While the biological mechanisms of these effects are not known, inflammation may play a key role as it is both elevated by psychological stress and involved in the development and progression of CVD. In a prospective study of patients with stable CVD (n = 979), we examined if higher lifetime trauma exposure was associated with elevated levels of inflammation at baseline and at five-year follow-up, and with greater increases in inflammation over time. Inflammation was indexed by a composite score incorporating the inflammatory markers interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), C-reactive protein (CRP) and resistin. In follow-up analyses, we adjusted for sociodemographic factors, psychiatric disorders and health behaviors that were significantly associated with trauma exposure. Higher trauma exposure was associated with elevated inflammation at baseline (β = .09, p = .01) and at five-year follow-up (β = .09, p = .03). While levels of inflammation increased from baseline to follow-up in the sample, there was no significant association between trauma exposure and rate of change in inflammation. Findings were robust to adjustments for sociodemographic factors and psychiatric disorders, but health behaviors appeared to contribute to the association between trauma and inflammation at follow-up. This is the first large-scale demonstration of an association between lifetime trauma exposure and inflammation. High lifetime exposure to traumatic stress may contribute to an accelerated rate of CVD progression through elevated inflammation.

ObjectiveHere we use a novel ELISA that is specific for full-length visfatin (PBEF/NAMPT), compare it with the existing C-terminal based assay and use it to investigate associations of visfatin with metabolic parameters.Design, patients and measurementsWe established the specificity and effectiveness of the new ELISA and evaluated the associations of full-length visfatin with clinical, anthropometric and metabolic parameters in a cross-sectional study of 129 Thai subjects, consisting of 50 outpatients with type 2 diabetes and 79 healthy volunteers.ResultsThe new ELISA accurately recovered full-length recombinant visfatin and detected visfatin secreted by primary human and rat adipocytes. We found serum full-length visfatin was significantly higher in subjects with diabetes compared to their nondiabetic peers (median 2.75 vs. 2.22 ng/ml, P = 0.0142). After adjustment for age, gender and traditional metabolic risk factors, adjusted mean visfatin remained significantly higher in the diabetes group (3.80 vs. 2.10 ng/ml, P = 0.0021). On Spearman univariate correlation analysis, visfatin was significantly associated with resistin (r = 0.30, P = 0.0011), but not with any other anthropometric or metabolic variables, including adiponectin multimers. On multiple linear regression analysis, the only covariates independently associated with visfatin were diabetes (t = 3.11, P = 0.0024) and log resistin (t = 2.68, P = 0.0086).ConclusionsCirculating visfatin is independently associated with diabetes and resistin concentration, but is not related to adiponectin multimers or other metabolic covariates. These data are suggestive of a potential role of visfatin in subclinical inflammatory states.

ObjectiveHere we use a novel ELISA that is specific for full-length visfatin (PBEF/NAMPT), compare it with the existing C-terminal based assay and use it to investigate associations of visfatin with metabolic parameters.Design, patients and measurementsWe established the specificity and effectiveness of the new ELISA and evaluated the associations of full-length visfatin with clinical, anthropometric and metabolic parameters in a cross-sectional study of 129 Thai subjects, consisting of 50 outpatients with type 2 diabetes and 79 healthy volunteers.ResultsThe new ELISA accurately recovered full-length recombinant visfatin and detected visfatin secreted by primary human and rat adipocytes. We found serum full-length visfatin was significantly higher in subjects with diabetes compared to their nondiabetic peers (median 2.75 vs. 2.22 ng/ml, P = 0.0142). After adjustment for age, gender and traditional metabolic risk factors, adjusted mean visfatin remained significantly higher in the diabetes group (3.80 vs. 2.10 ng/ml, P = 0.0021). On Spearman univariate correlation analysis, visfatin was significantly associated with resistin (r = 0.30, P = 0.0011), but not with any other anthropometric or metabolic variables, including adiponectin multimers. On multiple linear regression analysis, the only covariates independently associated with visfatin were diabetes (t = 3.11, P = 0.0024) and log resistin (t = 2.68, P = 0.0086).ConclusionsCirculating visfatin is independently associated with diabetes and resistin concentration, but is not related to adiponectin multimers or other metabolic covariates. These data are suggestive of a potential role of visfatin in subclinical inflammatory states.