Serum adiponectin in relation to race-ethnicity and vascular risk factors in the Northern Manhattan Study

Total adiponectin in indigenous Melanesians on Kitava

OBJECTIVES

Experimental and small human studies have indicated that high total adiponectin levels have beneficial cardiometabolic effects. In contrast, however, high total adiponectin levels are also associated with higher all-cause and cardiovascular mortality in thoroughly adjusted epidemiological studies. To gain further insight into these seemingly contradictory results, we report results on total adiponectin from the indigenous Melanesian population of Kitava, Trobriand Islands, Papua New Guinea, where an apparent absence of cardiometabolic disease has been previously reported.

METHODS

Fasting levels of serum total adiponectin were measured cross-sectionally in ≥40-year-old Kitavans (n = 102) and Swedish controls matched for age and sex (n = 108). Multivariable linear regression was used for the analysis of associations with total adiponectin when controlled for group, sex, smoking, hypertension and/or type 2 diabetes, age, and body mass index.

RESULTS

Total adiponectin was lower for Kitavans compared to Swedish controls (Median [Mdn] 4.6 μg/mL, range 1.0-206 μg/mL and Mdn 9.7 μg/mL, range 3.1-104 μg/mL, respectively, r = .64, p < .001). Lower total adiponectin was associated with Kitavan group, male sex (only in Swedish controls), smoking (only in Kitavans and Swedish controls combined), younger age (not in Swedish controls), higher BMI, lower total, low-density lipoprotein, high-density lipoprotein (HDL) (only in Kitavans and Swedish controls combined), and non-HDL cholesterol, and higher anti-PC IgG (only in Kitavans and Swedish controls combined).

CONCLUSION

Total adiponectin in Kitavans was significantly lower than in Swedish controls.

Apigenin-6-C-glucoside ameliorates MASLD in rodent models via selective agonism of adiponectin receptor 2

Adiponectin plays key roles in energy metabolism and ameliorates inflammation, oxidative stress, and mitochondrial dysfunction via its primary receptors, adiponectin receptors -1 and 2 (AdipoR1 and AdipoR2). Systemic depletion of adiponectin causes various metabolic disorders, including MASLD; however adiponectin supplementation is not yet achievable owing to its large size and oligomerization-associated complexities. Small-molecule AdipoR agonists, thus, may provide viable therapeutic options against metabolic disorders. Using a novel luciferase reporter-based assay here, we have identified Apigenin-6-C-glucoside (ACG), but not apigenin, as a specific agonist for the liver-rich AdipoR isoform, AdipoR2 (EC50: 384 pM) with >10000X preference over AdipoR1. Immunoblot analysis in HEK-293 overexpressing AdipoR2 or HepG2 and PLC/PRF/5 liver cell lines revealed rapid AMPK, p38 activation and induction of typical AdipoR targets PGC-1α and PPARα by ACG at a pharmacologically relevant concentration of 100 nM (reported cMax in mouse; 297 nM). ACG-mediated AdipoR2 activation culminated in a favorable modulation of key metabolic events, including decreased inflammation, oxidative stress, mitochondrial dysfunction, de novo lipogenesis, and increased fatty acid β-oxidation as determined by immunoblotting, QRT-PCR and extracellular flux analysis. AdipoR2 depletion or AMPK/p38 inhibition dampened these effects. The in vitro results were recapitulated in two different murine models of MASLD, where ACG at 10 mg/kg body weight robustly reduced hepatic steatosis, fibrosis, proinflammatory macrophage numbers, and increased hepatic glycogen content. Together, using in vitro experiments and rodent models, we demonstrate a proof-of-concept for AdipoR2 as a therapeutic target for MASLD and provide novel chemicobiological insights for the generation of translation-worthy pharmacological agents.

Ethnic Disparities in the Risk Factors, Morbidity, and Mortality of Cardiovascular Disease in People With Diabetes

Cardiovascular disease (CVD) is the leading cause of death in people with diabetes. Compared with European Americans, African Americans have more favorable lipid profiles, as indicated by higher high-density lipoprotein cholesterol, lower triglycerides, and less dense low-density lipoprotein particles. The less atherogenic lipid profile translates to lower incidence and prevalence of CVD in African Americans with diabetes, despite higher rates of hypertension and obesity. However, African Americans with CVD experience worse clinical outcomes, including higher mortality, compared with European Americans. This mini-review summarizes the epidemiology, pathophysiology, mechanisms, and management of CVD in people with diabetes, focusing on possible factors underlying the "African American CVD paradox" (lower CVD incidence/prevalence but worse outcomes). Although the reasons for the disparities in CVD outcomes remain to be fully elucidated, we present a critical appraisal of the roles of suboptimal control of risk factors, inequities in care delivery, several biological factors, and psychosocial stress. We identify gaps in current knowledge and propose areas for future investigation.

Reevaluating Adiponectin's impact on obesity hypertension: a Chinese case-control study

BACKGROUND

Obesity and hypertension are major risk factors for cardiovascular diseases that affect millions of people worldwide. Both conditions are associated with chronic low-grade inflammation, which is mediated by adipokines such as adiponectin. Adiponectin is the most abundant adipokine that has a beneficial impact on metabolic and vascular biology, while high serum concentrations are associated with some syndromes. This "adiponectin paradox" still needs to be clarified in obesity-associated hypertension. The aim of this study was to investigate how adiponectin affects blood pressure, inflammation, and metabolic function in obesity hypertension using a Chinese adult case-control study.

METHODS

A case-control study that had finished recruiting 153 subjects divided as four characteristic groups. Adiponectin serum levels were tested by ELISA in these subjects among these four characteristic Chinese adult physical examination groups. Waist circumference (WC), body mass index (BMI), systolic blood pressure (SB), diastolic blood pressure (DB), and other clinical laboratory data were collected. Analyzation of correlations between the research index and differences between groups was done by SPSS.

RESULTS

Serum adiponectin levels in the| normal healthy group (NH group) were significantly higher than those in the newly diagnosed untreated just-obesity group (JO group), and negatively correlated with the visceral adiposity index. With multiple linear egression analysis, it was found that, for serum adiponectin, gender, serum albumin (ALB), alanine aminotransferase (ALT) and high-density lipoprotein cholesterol (HDLC) were the significant independent correlates, and for SB, age and HDLC were the significant independent correlates, and for DB, alkaline phosphatase (ALP) was the significant independent correlate. The other variables did not reach significance in the model.

CONCLUSIONS

Our study reveals that adiponectin's role in obesity-hypertension is multifaceted and is influenced by the systemic metabolic homeostasis signaling axis. In obesity-related hypertension, compensatory effects, adiponectin resistance, and reduced adiponectin clearance from impaired kidneys and liver all contribute to the "adiponectin paradox".

Estradiol overcomes adiponectin-resistance in diabetic mice by regulating skeletal muscle adiponectin receptor 1 expression

Adiponectin and insulin resistance creates a vicious cycle that exacerbates type 2 diabetes. Earlier, we observed that female leptin receptor-deficient BLKS mice (BKS-db/db) were more sensitive to an adiponectin mimetic GTDF than males, which led us to explore if E2 plays a crucial role in modulation of adiponectin-sensitivity. Male but not female BKS-db/db mice were resistant to metabolic effects of globular adiponectin treatment. Male BKS-db/db displayed reduced skeletal muscle AdipoR1 protein expression, which was consequent to elevated polypyrimidine tract binding protein 1 (PTB) and miR-221. E2 treatment in male BKS-db/db, and ovariectomized BALB/c mice rescued AdipoR1 protein expression via downregulation of PTB and miR-221, and also directly increased AdipoR1 mRNA by its classical nuclear receptors. Estrogen receptor regulation via dietary or pharmacological interventions may improve adiponectin resistance and consequently ameliorate insulin resistance in type 2 diabetes.

Adiponectin is associated with insulin sensitivity in white European men but not black African men

AIMS

We aimed to assess ethnic differences in inflammatory markers and their relationships with insulin sensitivity and regional adiposity between white European and black African men.

METHODS

A total of 53 white European and 53 black African men underwent assessment of inflammatory markers alongside Dixon-magnetic resonance imaging to quantify subcutaneous and visceral adipose tissue and intrahepatic lipid. A hyperinsulinaemic-euglycaemic clamp was used to measure whole-body and adipose tissue insulin sensitivity. To assess ethnic differences in relationships, the statistical significance of an interaction term between adipokines and ethnic group was tested in multivariable regression models.

RESULTS

The black African men exhibited significantly lower adiponectin and tumour necrosis factor-α (TNF-α) and greater interleukin-10 (IL-10) compared to white European men (all p < 0.05). There were no statistically significant ethnic differences in leptin, resistin, IL-6, interferon-γ, IL-13, IL-1β, IL-8 and vascular endothelial growth factor. Several relationships differed significantly by ethnicity such that they were stronger in white European than black African men including IL-6 with visceral adipose tissue; adiponectin with subcutaneous adipose tissue; leptin with intrahepatic lipid; adiponectin, IL-6 and TNF-α with whole-body insulin sensitivity and TNF-α with adipose tissue insulin sensitivity (all pinteraction <0.05). Leptin significantly predicted whole-body insulin sensitivity in white European (R²  = 0.51) and black African (R²  = 0.29) men; however, adiponectin was a statistically significant predictor in only white European men (R²  = 0.22).

CONCLUSIONS

While adiponectin is lower in black African men, its insulin sensitising effects may be greater in white men suggesting that the role of adipokines in the development of type 2 diabetes may differ by ethnicity.

Correlation between plasma ZAG and adiponectin in older adults: gender modification and frailty specificity

Background

Adiponectin and zinc alpha2-glycoprotein (ZAG) are associated with frailty. This study aims to further examine the association of adiponectin with ZAG.

Methods

Outpatients aged 65 years or older with chronic disease followed up in a hospital-based program were recruited for a comprehensive geriatric assessment. We excluded outpatients who were bedridden, residing in a nursing home, with expected life expectancy less than 6 months, or with severe hearing or communication impairment. Plasma ZAG and adiponectin levels were measured. Association between plasma ZAG and adiponectin levels was analyzed by univariate and multivariable linear regression analyses.

Results

A total of 189 older adults were enrolled (91 men and 98 women, mean age: 77.2 ± 6.1 years). Log-transformed plasma ZAG level was 1.82 ± 0.11 μg/mL, and it was significantly higher in men than that in women (1.85 ± 0.12 vs 1.79 ± 0.10 μg/mL, P = .0006). Log-transformed plasma adiponectin level was 1.00 ± 0.26 μg/mL, and there was no significant gender difference (P = .195). Overall, plasma ZAG level positively correlated with plasma adiponectin level in the multivariable linear regression analysis (P = .0085). The gender-specific significance, however, was less clear: this relationship was significant in men (P = .0049) but not in women (P = .2072). To be more specific by frailty phenotype components, plasma adiponectin was positively correlated with weight loss (P = .0454) and weakness (P = .0451).

Conclusions

Both of ZAG and adiponectin may be potential frailty biomarkers. Plasma ZAG is an independent factor of plasma adiponectin, especially in older male adults.

Association of Adiponectin and Vitamin D With Tumor Infiltrating Lymphocytes and Survival in Stage III Colon Cancer

Background

Adipocyte-derived adiponectin may play a role in the host inflammatory response to cancer. We examined the association of plasma adiponectin with the density of tumor-infiltrating lymphocytes (TILs) in colon cancers and with vitamin D, clinicopathological features, and patient survival.

Methods

Plasma adiponectin and 25-hydroxyvitamin D [25(OH)D] were analyzed by radioimmunoassay in 600 patients with stage III colon cancer who received FOLFOX-based adjuvant chemotherapy (NCCTG N0147 [Alliance]). TIL densities were determined in histopathological sections. Associations with disease-free survival (DFS), time to recurrence, and overall survival were evaluated by multivariable Cox regression adjusting for potential confounders (ie, body mass index, race, TILs, and N stage). All statistical tests were 2-sided.

Results

We found a statistically significant reduction in adiponectin, but not 25(OH)D, levels in tumors with high vs low TIL densities (median = 6845 vs 8984 ng/mL; P = .04). A statistically significant reduction in adiponectin was also observed in obese (body mass index >30 kg/m²) vs nonobese patients (median = 6608 vs 12 351 ng/mL; P < .001), in men vs women (median = 8185 vs 11 567 ng/mL; P < .001), in Blacks vs Whites or Asians (median = 6412 vs 8847 vs 7858 ng/mL; P < .03), and in those with fewer lymph node metastases (N1 vs N2: median = 7768 vs 9253 ng/mL; P = .01). Insufficiency of 25(OH)D (<30 ng/mL) was detected in 291 (48.5%) patients. In multivariable analyses, neither adiponectin nor 25(OH)D were associated with a statistically significant difference in DFS, overall survival , or time to recurrence in models adjusted for potential confounders. We found a statistically significant association of TILs with prognosis, yet no such interaction was observed for the association of adiponectin with TILs for DFS.

Conclusions

Lower circulating adiponectin levels were associated with a statistically significant increase in TIL densities in colon cancers, indicating an enhanced antitumor immune response. In contrast to TILs, neither adiponectin nor 25(OH)D was independently prognostic.

The Combination of High Levels of Adiponectin and Insulin Resistance Are Affected by Aging in Non-Obese Old Peoples

BACKGROUND

Adipokine dysregulation is a key feature of insulin resistance and a metabolic syndrome associated with obesity. Low adiponectin levels are associated with higher risks of cardiovascular diseases (CVD). However, high adiponectin levels have also been associated with increased all-cause and cardiovascular mortality in the elderly. This adiponectin paradox has yet to be clarified, which has hindered our understanding of the biological role of adiponectin. Adipokine dysregulation and insulin resistance are also associated with energy-deprivation conditions, such as frailty in old age. The objective of this study was to investigate the association between plasma adiponectin and insulin resistance using the homeostasis model assessment for insulin resistance (HOMA-IR) classified by age. In particular, we sought to determine the factors of the subjects associated with both high adiponectin levels and HOMA-IR (H-adiponectin/H-HOMA) and high adiponectin levels and low HOMA-IR (H-adiponectin/L-HOMA).

METHODS

The eligible subjects in this cross-sectional study were 33,216 individuals who had undergone health checkups at the Physical Checkup Center of Sumitomo Hospital between April 2008 and December 2018. After excluding 26,371 individuals who were under 60 years old, 529 who had been taking medications for diabetes mellitus, and 690 with missing data, the present study included 5,673 (3,467 males, 2,206 females) subjects with no missing data. The relationship between serum adiponectin levels and HOMA-IR was assessed using logistic regression models adjusted by clinically relevant factors.

RESULTS

In the multivariable logistic regression analysis, age and low BMI were shown to positively correlate with the characteristics of H-adiponectin/H-HOMA. In females, systolic blood pressure was also shown to be an associated factor.

CONCLUSION

In conclusion, this study showed that aging or a low BMI may contribute to high adiponectin levels and insulin resistance.

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

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

The association of maternal obesity and race with serum adipokines in pregnancy and postpartum: Implications for gestational weight gain and infant birth weight

Adiponectin and leptin are hormones known to play roles in maternal metabolism during pregnancy. Levels of these hormones have been demonstrated to vary based on adiposity and race. However, there is a lack of data concerning the relationship between race and the change of adiponectin and leptin throughout pregnancy. The purpose of this study was to examine serum levels of adiponectin, leptin, and leptin-to-adiponectin ratio (LAR) throughout pregnancy and to assess their association with gestational weight gain (GWG) and infant birth weight while considering the effects of race and pre-pregnancy body mass index (BMI). Serum levels of adiponectin, leptin, gestational weight gain, and infant birth weight were measured in 80 pregnant women at early (12.4 ​± ​1.3 weeks gestation), mid (20.6 ​± ​1.3 weeks gestation), late pregnancy (29.2 ​± ​1.4 weeks gestation), and 7-11 weeks postpartum (8.8 ​± ​0.8 weeks). In women overall, serum adiponectin decreased across pregnancy and increased at postpartum (p ​= ​0.17.) At each prenatal timepoint, both black race and obesity were associated with lower adiponectin (ps ​< ​0.05). In women overall, serum leptin increased across pregnancy, and declined at postpartum. At every assessment, a stepwise increase in leptin was observed in relation to BMI class. Black women with obesity had markedly higher LAR in mid- and late pregnancy and postpartum than all other groups (p ​< ​0.05). Serum leptin during pregnancy was significantly associated with total GWG in both black and white women (ps ​< ​0.005). Neither adiponectin, leptin, nor LAR were associated with infant birth weight. Race and BMI both have significant effects on serum adiponectin, leptin, and LAR levels in pregnancy and postpartum. Notably, the combined effects of race and BMI result in markedly higher LAR among black women with obesity. Implications for racial disparities in metabolic syndrome and postpartum weight retention remain to be explicated.

The genomic basis of environmental adaptation in house mice

House mice (Mus musculus) arrived in the Americas only recently in association with European colonization (~400-600 generations), but have spread rapidly and show evidence of local adaptation. Here, we take advantage of this genetic model system to investigate the genomic basis of environmental adaptation in house mice. First, we documented clinal patterns of phenotypic variation in 50 wild-caught mice from a latitudinal transect in Eastern North America. Next, we found that progeny of mice from different latitudes, raised in a common laboratory environment, displayed differences in a number of complex traits related to fitness. Consistent with Bergmann's rule, mice from higher latitudes were larger and fatter than mice from lower latitudes. They also built bigger nests and differed in aspects of blood chemistry related to metabolism. Then, combining exomic, genomic, and transcriptomic data, we identified specific candidate genes underlying adaptive variation. In particular, we defined a short list of genes with cis-eQTL that were identified as candidates in exomic and genomic analyses, all of which have known ties to phenotypes that vary among the studied populations. Thus, wild mice and the newly developed strains represent a valuable resource for future study of the links between genetic variation, phenotypic variation, and climate.

From Sea to Shining Sea and the Great Plains to Patagonia: A Review on Current Knowledge of Diabetes Mellitus in Hispanics/Latinos in the US and Latin America

The past two decades have witnessed many advances in the prevention, treatment, and control of diabetes mellitus (DM) and its complications. Increased screening has led to a greater recognition of type 2 diabetes mellitus (type 2 DM) and prediabetes; however, Hispanics/Latinos, the largest minority group in the US, have not fully benefited from these advances. The Hispanic/Latino population is highly diverse in ancestries, birth places, cultures, languages, and socioeconomic backgrounds, and it populates most of the Western Hemisphere. In the US, the prevalence of DM varies among Hispanic/Latino heritage groups, being higher among Mexicans, Puerto Ricans, and Dominicans, and lower among South Americans. The risk and prevalence of diabetes among Hispanics/Latinos are significantly higher than in non-Hispanic Whites, and nearly 40% of Hispanics/Latinos with diabetes have not been formally diagnosed. Despite these striking facts, the representation of Hispanics/Latinos in pharmacological and non-pharmacological clinical trials has been suboptimal, while the prevalence of diabetes in these populations continues to rise. This review will focus on the epidemiology, etiology and prevention of type 2 DM in populations of Latin American origin. We will set the stage by defining the terms Hispanic, Latino, and Latin American, explaining the challenges identifying Hispanics/Latinos in the scientific literature and databases, describing the epidemiology of diabetes-including type 2 DM and gestational diabetes mellitus (GDM)-and cardiovascular risk factors in Hispanics/Latinos in the US and Latin America, and discussing trends, and commonalities and differences across studies and populations, including methodology to ascertain diabetes. We will discuss studies on mechanisms of disease, and research on prevention of type 2 DM in Hispanics/Latinos, including women with GDM, youth and adults; and finalize with a discussion on lessons learned and opportunities to enhance research, and, consequently, clinical care oriented toward preventing type 2 DM in Hispanics/Latinos in the US and Latin America.

Circulating adiponectin concentration is inversely associated with glucose tolerance and insulin secretion in people with newly diagnosed diabetes

AIMS

To examine the hypothesis that changes in serum adiponectin concentration inversely relate to changes in glucose tolerance and β-cell function already during the early stage of disease progression in recently diagnosed Type 1 and Type 2 diabetes mellitus.

METHODS

Participants in the prospective observational German Diabetes Study (Type 2 diabetes, n = 94; Type 1 diabetes, n = 42) underwent i.v. glucose tolerance and glucagon stimulation testing to assess pre-hepatic β-cell function, glucose tolerance index and C-peptide secretion within the first year of diabetes diagnosis and 2 years later. Associations of changes in serum concentrations of total adiponectin, high-molecular-weight adiponectin and their ratio with changes in the aforementioned metabolic variables were calculated using linear regression.

RESULTS

Among people with Type 2 diabetes, 2-year increases in high-molecular-weight adiponectin and in high-molecular-weight/total adiponectin ratio were associated with decreases in glucose tolerance index of 0.1%/min (P = 0.020) and 0.8%/min (P = 0.013), respectively. Increases in high-molecular-weight/total adiponectin ratio were related to decreases in acute C-peptide secretion of 54.6% (P = 0.020). Among people with Type 1 diabetes, 2-year increases in total adiponectin were associated with 2-year decreases in acute C-peptide secretion of 56.2% (P = 0.035).

CONCLUSIONS

Increases in adiponectin concentrations in the first 2 years after diagnosis were related to a worsening of acute insulin secretion and glucose tolerance index in Type 1 and Type 2 diabetes. (Clinical Trials Registry no.: NCT01055093).

Adiponectin, Insulin Sensitivity, β-Cell Function, and Racial/Ethnic Disparity in Treatment Failure Rates in TODAY

OBJECTIVE

The Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) study demonstrated that glycemic failure rates in the three treatments combined-metformin plus rosiglitazone, metformin alone, and metformin plus lifestyle-were higher in non-Hispanic blacks (NHB; 52.8%) versus non-Hispanic whites (NHW; 36.6%) and Hispanics (H; 45.0%). Moreover, metformin alone was less effective in NHB versus NHW versus H youth. This study describes treatment-associated changes in adiponectin, insulin sensitivity, and β-cell function over time among the three racial/ethnic groups to understand potential mechanism(s) responsible for this racial/ethnic disparity.

RESEARCH DESIGN AND METHODS

TODAY participants underwent periodic oral glucose tolerance tests to determine insulin sensitivity, C-peptide index, and oral disposition index (oDI), with measurements of total and high-molecular-weight adiponectin (HMWA).

RESULTS

At baseline NHB had significantly lower HMWA than NHW and H and exhibited a significantly smaller increase (17.3% vs. 33.7% vs. 29.9%, respectively) during the first 6 months overall. Increases in HMWA were associated with reductions in glycemic failure in the three racial/ethnic groups combined (hazard ratio 0.61, P < 0.0001) and in each race/ethnicity separately. Over time, HMWA was significantly lower in those who failed versus did not fail treatment, irrespective of race/ethnicity. There were no differences in treatment-associated temporal changes in insulin sensitivity, C-peptide index, and oDI among the three racial/ethnic groups.

CONCLUSIONS

HMWA is a reliable biomarker of treatment response in youth with type 2 diabetes. The diminutive treatment-associated increase in HMWA in NHB (∼50% lower) compared with NHW and H may explain the observed racial/ethnic disparity with higher therapeutic failure rates in NHB in TODAY.

Elevated adiponectin but varied response in circulating leptin levels to falciparum malaria in type 2 diabetics and non-diabetic controls

Background

To investigate effects of falciparum malaria on circulating levels of leptin and adiponectin in type 2 diabetes mellitus (T2DM) and non-diabetic controls in relation to measures of adiposity.

Methods

Levels of leptin and adiponectin were measured in 100 type 2 diabetics and 100 age-matched controls before and during falciparum malaria in a 2-year prospective study. Also, waist circumference (WC), weight, height and hip circumference were measured. Body mass index (BMI) and waist-to-hip ratio (WHR) were computed.

Results

At baseline, diabetics had significantly (p < 0.05) higher WC and BMI but lower WHR, leptin and adiponectin levels. Baseline leptin correlated positively with WC (r = 0.633; p < 0.001) and BMI (r = 0.63; p < 0.001) in diabetics but only BMI (0.562; p < 0.001) in non-diabetic controls. Baseline leptin and adiponectin correlated positively (r = 0.249; p = 0.029) in non-diabetic respondents only. Adiponectin correlated negatively with WC (r = −0.58; p = 0.006) in diabetic males only. During malaria, mean levels of leptin and adiponectin were comparable (p > 0.05) between diabetics and controls. However, compared to baseline levels, significant (p < 0.001) elevation of adiponectin was found in both study groups. In respect of leptin, significant (p < 0.001) rise but decline was observed in diabetics and controls respectively. Malaria-induced leptin correlated negatively with adiponectin (r = −0.694; p < 0.001) in non-diabetic controls only.

Conclusion

Diabetics and controls exhibited increased adiponectin levels due to falciparum malaria but differed in response in terms of leptin levels.

Adiponectin levels predict prediabetes risk: the Pathobiology of Prediabetes in A Biracial Cohort (POP-ABC) study

BACKGROUND

Adiponectin levels display ethnic disparities, and are inversely associated with the risk of type 2 diabetes (T2DM). However, the association of adiponectin with prediabetes risk in diverse populations has not been well-studied. Here, we assessed baseline adiponectin levels in relation to incident prediabetes in a longitudinal biracial cohort.

RESEARCH DESIGN AND METHODS

The Pathobiology of Prediabetes in A Biracial Cohort study followed non-diabetic offspring of parents with T2DM for the occurrence of prediabetes, defined as impaired fasting glucose and/or impaired glucose tolerance. Assessments at enrollment and during follow-up included a 75 g oral glucose tolerance test, anthropometry, biochemistries (including fasting insulin and adiponectin levels), insulin sensitivity and insulin secretion. Logistic regression was used to evaluate the contribution of adiponectin to risk of progression to prediabetes.

RESULTS

Among the 333 study participants (mean (SD) age 44.2 (10.6) year), 151(45.3%) were white and 182 (54.8%) were black. During approximately 5.5 (mean 2.62) years of follow-up, 110 participants (33%) progressed to prediabetes (N=100) or T2DM (N=10), and 223 participants (67%) were non-progressors. The mean cohort adiponectin level was 9.41+5.30 μg/mL (range 3.1-45.8 μg/mL); values were higher in women than men (10.3+5.67 μg/mL vs 7.27+3.41 μg/mL, p<0.0001) and in white than black offspring (10.7+5.44 μg/mL vs 8.34+4.95 μg/mL, p<0.0001). Adiponectin levels correlated inversely with adiposity and glycemia, and positively with insulin sensitivity and high-density lipoprotein cholesterol levels. Baseline adiponectin strongly predicted incident prediabetes: the HR for prediabetes per 1 SD (approximately 5 μg/mL) higher baseline adiponectin was 0.48 (95% CI 0.27 to 0.86, p=0.013).

CONCLUSIONS

Among healthy white and black adults with parental history of T2DM, adiponectin level is a powerful risk marker of incident prediabetes. Thus, the well-known association of adiponectin with diabetes risk is evident at a much earlier stage in pathogenesis, during transition from normoglycemia to prediabetes.

Associations of serum adiponectin with markers of cardio-metabolic disease risk in Indigenous Australian adults with good health, diabetes and chronic kidney disease

The higher serum adiponectin concentrations observed in females are often attributed to differences in adiposity or sex hormones. There is little data describing adiponectin in Indigenous Australians, and no studies examining its association with cardio-metabolic disease risk markers and chronic kidney disease (CKD).

AIM

To describe the relationship of serum adiponectin with cardio-metabolic disease risk markers and kidney function in a community-based sample of Indigenous Australian adults, with particular reference to sex-specific differences.

METHODS

A cross-sectional analysis of a community-based volunteer sample of 548 Indigenous Australian adults (62% female), stratified into five cardio-metabolic risk groups ranging from good health (strata-1) to high cardio-metabolic risk and low measured glomerular filtration rate (mGFR, <60ml/min/1.73m²) (strata-5). We examined serum adiponectin concentrations with cardio-metabolic risk markers, albuminuria and mGFR.

RESULTS

Indigenous Australian females had a lower than expected adiponectin concentration (3.5μg/ml), which was higher than males in strata 1-4 (as in other populations), but not in strata-5 (mGFR<60, p=0.19), and higher leptin: adiponectin ratio than other populations (7.8ng/μg - strata-1, healthy females; 12.2ng/μg - strata-3, females with diabetes and mGFR≥90). Female-gender, HDL-cholesterol (positive), mGFR and waist: hip ratio (WHR) (inverse) were independently associated with log-adiponectin when mGFR≥60; when mGFR<60, female-gender was associated with 0.27 units lower log-adiponectin.

CONCLUSION

Female-gender was not associated with higher adiponectin concentrations in Indigenous Australians with mGFR<60ml/min/1.73m². High WHR was frequent in both genders, and inversely associated with adiponectin. Longitudinal studies are needed to examine relationships of serum adiponectin, obesity and cardiovascular disease events in Indigenous Australians.

Accuracy of plasma interleukin-18 and adiponectin concentrations in predicting metabolic syndrome and cardiometabolic disease risk in middle-age Brazilian men

The aims of this cross-sectional study were to explore the ability of serum interleukin 18 (IL-18) and adiponectin to identify metabolic syndrome (MetS), and to verify their association with an index of central lipid overaccumulation (lipid accumulation product (LAP)) and cardiometabolic risk factors in a population of middle-aged Brazilian men. A group of 218 apparently healthy middle-aged Brazilian men (age, 50.3 ± 4.97 years) underwent anthropometric, clinical, sociodemographic, and standard serum biochemical assessments. LAP was calculated and the study participants were categorized into 3 groups according to serum IL-18 and adiponectin cut-points tertiles to verify the association of these biomarkers with cardiometabolic risk factors. The MetS group had more less active (p = 0.03) and obese (p < 0.01) individuals who exhibited higher IL-18 (p < 0.01) and lower adiponectin (p < 0.01) than did those in the group with no MetS. After adjustments (age, smoking, alcohol consumption, physical activity level, and total body fat), serum IL-18 ≥ 336.4 pg/mL was an independent factor for MetS occurrence and it was directly associated with LAP (≥51.28), central obesity, hypertriglyceridemia, and hypertension (p < 0.05), but not with high-density lipoprotein cholesterol (HDL-C). Serum adiponectin ≥ 7.02 μg/mL was negatively associated with MetS occurrence, LAP, hypertriglyceridemia, and low HDL-C (p < 0.05), but not with central obesity and hypertension. In conclusion, both IL-18 and adiponectin demonstrated the ability to identify MetS in this population, with IL-18 being more accurate. The association of these biomamarkers with LAP and cardiometabolic risk factors highlights its relevance as a diagnostic tool.

Plasma adiponectin levels in schizophrenia and role of second-generation antipsychotics: a meta-analysis

BACKGROUND

People with schizophrenia are more likely than general population to suffer from metabolic abnormalities, with second-generation antipsychotics (SGAs) increasing the risk. Low plasma adiponectin levels may lead to metabolic dysregulations but evidence in people with schizophrenia, especially for the role of SGAs, is still inconclusive.

OBJECTIVE

To compare plasma adiponectin levels between people with schizophrenia and healthy controls, and to estimate the relative effect of schizophrenia and SGAs on adiponectin.

METHODS

We performed a systematic review and meta-analysis of observational studies published up to 13 June 2014 in main electronic databases. Pooled standardized mean differences (SMDs) between index and control groups were generated. Appropriate subanalyses and additional subgroup analyses were carried out.

RESULTS

Data from 2735 individuals, 1013 with and 1722 without schizophrenia, respectively, were analysed. Schizophrenia was not associated with lower adiponectin levels (SMD of -0.28, 95%CI: -0.59, 0.04; p=0.09). However, individuals with schizophrenia taking SGAs had plasma levels significantly lower than controls (p=0.002), which was not the case of drug free/drug naïve subjects (p=0.52). As regards single antipsychotic drugs clozapine (p<0.001) and olanzapine (p=0.04)--but not risperidone (p=0.88)--were associated with adiponectin levels lower than controls.

CONCLUSIONS

People with schizophrenia per se may not have levels of adiponectin lower than controls, though treatment with SGAs is associated with this metabolic abnormality. This bears clinical significance because of hypoadiponectinemia involvement in cardiovascular diseases, even if mechanisms whereby SGAs affect adiponectin remain unexplained. Longitudinal studies evaluating long-term effects of SGAs on adiponectin are needed.

Lower levels of plasma adiponectin and endothelial progenitor cells are associated with large artery atherosclerotic stroke

BACKGROUND

Both adiponectin and endothelial progenitor cells (EPCs) have been proposed recently with anti-atherosclerosis effects. However, their impacts on vascular outcomes in patients with large artery atherosclerosis (LAA) are unclear. This study aimed to investigate the relationship between adiponectin, EPCs and stroke with a case-control design.

METHODS

The study cohort included 127 patients (61.3 ± 11.0 years; 73.2% men) with LAA stroke and 58 control subjects (60.9 ± 9.2 years; 70.7% men) referred for adiponectin and EPCs levels testing. We collected demographic, clinical, angiographical features, and laboratory data. Influence of adiponectin and EPCs levels on cerebral atherosclerosis and LAA stroke was analyzed with regression models.

RESULTS

The levels of adiponectin and EPCs in atherosclerotic stroke patients were significantly lower compared with matched controls (p < 0.05). Logistic regression analysis identified that reduced levels of adiponectin and EPCs were closely correlated with cerebral atherosclerosis and LAA stroke. The associations remained significant after adjustment for age, sex and other confounders. Additionally, partial correlation analysis revealed a significant positive association between adiponectin and three subpopulations of EPCs levels (CD34(+)CD133(+)CD309(+)cells: r = 0.510, p = 0.001; CD34(+) CD133(-)CD309(+)cells: r = 0.262, p = 0.004; CD34(-)CD133(+)CD309(+)cells: r = 0.348, p < 0.001).

CONCLUSIONS

Adiponectin is positively correlated with EPCs levels, and both of them are independently associated with LAA stroke.

Serum adiponectin levels may be associated with the pathogenesis of hepatocellular carcinoma

The aim of the meta-analysis described below was to investigate the correlation between serum levels of adiponectin (ADPN) and the pathogenesis of hepatocellular carcinoma (HCC). Relevant studies about serum ADPN levels and the pathogenesis of HCC were identified by searching electric databases and by manual search. The included studies were selected in strict accordance with the inclusion and exclusion criteria. Detailed criteria were described in "Materials and methods" section. Statistical analyses were conducted with the STATA 12.0 statistical software (StataCorp, College Station, TX, USA). A total of nine studies were incorporated into this meta-analysis after careful consideration, including 705 HCC patients and 1390 healthy controls. This meta-analysis demonstrated that the serum ADPN levels in HCC patients were significantly higher than those in healthy controls (standard mean difference (SMD) = 0.97, 95% confidence intervals (CI) = 0.02∼1.93, P < 0.05). The result of subgroup analysis by ethnicity revealed that serum ADPN levels in Caucasians and Asians were both obviously higher than those in healthy controls (Caucasians: SMD = 0.51, 95% CI = 0.30∼0.73, P < 0.001; Asians: SMD = 0.49, 95% CI = 0.06∼0.91, P < 0.05), but in Africans, the differences between HCC patients and controls had no statistical significance (SMD = 2.64, 95% CI = -3.01∼8.30, P = 0.36). The evidence obtained by this meta-analysis suggests that serum ADPN levels are associated with the pathogenesis of HCC. Further conclusion might be that increased serum levels of ADPN can inhibit tumor growth and play a protective role in the development of HCC.

Racial differences in adipose tissue distribution and risk of aggressive prostate cancer among men undergoing radiotherapy

BACKGROUND

Although elevated body mass index (BMI) has been associated with increased risk of aggressive prostate cancer, the importance of adipose tissue distribution is not well understood. We examined associations between overall and visceral obesity and aggressive prostate cancer risk. Moreover, given racial differences in adipose tissue distribution, we examined whether race modified these associations.

METHODS

We conducted a cross-sectional analysis of 308 radiotherapy-treated patients with prostate cancer within the Durham VA from 2005 to 2011. Multivariable logistic regression examined the association between BMI categories and tertiles of waist circumference (WC), visceral fat area (VFA), and periprostatic adipose tissue area (PPAT) with high-grade prostate cancer risk (Gleason score ≥7 vs. ≤6). Models stratified by race examined whether these associations differed between black and nonblack men.

RESULTS

Both elevated BMI (Ptrend = 0.054) and WC (Ptrend = 0.040) were associated with increased high-grade prostate cancer risk, with similar results between races, although the association with BMI was not statistically significant. In contrast, elevated VFA was associated with increased aggressive prostate cancer risk in black men (Ptrend = 0.002) but not nonblack men (Ptrend = 0.831), with a significant interaction between race and VFA (Pinteraction = 0.035). Though similar patterns were observed for PPAT, none was statistically significant.

CONCLUSIONS

Among men undergoing radiotherapy for prostate cancer, visceral obesity is associated with increased aggressive prostate cancer risk, particularly among black men. If confirmed in future studies, these results suggest that adipose tissue distribution differences may contribute to prostate cancer racial disparity.

IMPACT

These findings highlight the need to elucidate mechanisms contributing to racial differences in the association between visceral obesity and aggressive prostate cancer.

Comprehensive analysis of circulating adipokines and hsCRP association with cardiovascular disease risk factors and metabolic syndrome in Arabs

Background

Cardiovascular diseases (CVD) are a leading cause of death worldwide including the Middle East. This is caused in part by the dysregulation of adipose tissue leading to increased production of pro-inflammatory adipokines and reduction in cardio-protective adipokines such as adiponectin. Ethnicity has been recognized as a major factor in the association between CVD risk factors and the different circulating adipokines. In this study, for the first time, the relationship between traditional cardiovascular risk factors, Metabolic Syndrome (MetS) and circulating level of adipokines in Arab ethnicity was investigated.

Methods

We conducted a population-based cross-sectional survey on 379 adult Arab participants living in Kuwait. Traditional cardiovascular risk factors such as blood pressure (BP), low density lipoprotein (LDL) and triglyceride (TG) were measured. Plasma levels of circulating Leptin, Plasminogen Activator Inhibitor (PAI-1) visfatin, adiponectin, resistin and adipsin were assessed using the multiplexing immunobead-based assay.

Results

Circulating levels of High sensitivity C-Reactive Protein (hsCRP), Leptin, PAI-1 and adiponectin were significantly higher in Arab women than men (p < 0.0001). In multi-variate analysis, the homeostasis model assessment-insulin resistance (HOMA-IR) and body mass index (BMI) showed strong association with most of the biomarkers (p < 0.05). HsCRP showed significant association with all risk factors (p < 0.05). Leptin, PAI-1 and adipsin showed significant positive correlation with BMI, unlike adiponectin which showed inverse correlation (p < 0.05). Subjects in the highest tertile of leptin, PAI-1 and hsCRP had higher odds of having Metabolic Syndrome (MetS) (odd ratio [OR] = 3.02, 95% confidence interval [CI] = 1.47 – 6.19) and (OR = 2.52, 95% CI = 1.45 – 4.35), (OR = 4.26, 95% CI = 2.39 – 7.59) respectively. On the other hand subjects with highest tertile of adiponectin had lower odds of having MetS (OR = 0.22, 95% CI = 0.12 – 0.40). Leptin, PAI-1 and hsCRP showed significant positive association with increased MetS components (P-trend <0.05), while adiponectin was negatively associated with increased MetS components (P-trend <0.0001).

Conclusion

Our results show positive association between hsCRP, leptin, PAI-1 with increased MetS components and increase the odds of having MetS. Adiponectin on the other hand showed inverse correlation with MetS components and associated with reduction in MetS. Overall, our data highlights the significant clinical value these markers have in MetS especially hsCRP which can be used as good marker of low grade inflammation in Arabs.

Adiponectin and IL-6: Mediators of inflammation in progression of healthy to type 2 diabetes in Indian population

Aim The objective of the study was to identify the association if any, of inflammatory markers (adiponectin and IL-6) with fasting glucose in normoglycemic (healthy), prediabetic (impaired fasting glucose), and hyperglycemic (diabetic) people in Indian population. Methods Total 162 volunteers were distributed into 3 groups (normoglycemic, individuals with impaired fasting glucose, and hyperglycemic) as per ADA criterion. The blood chemistry parameters were analyzed and serum adiponectin and IL-6 levels were measured by ELISA. Results Significant reduction was observed in serum adiponectin level in hyperglycemic and impaired fasting glucose population compared with normoglycemic population. Significant reduction in adiponectin was also observed in impaired fasting glucose group compared with hyperglycemic group. Similarly significant increase was also observed in IL-6 level in hyperglycemic and impaired fasting glucose groups compared with normoglycemic group. Conclusions From our data it can be summarized that there is a significant change in both adiponectin (reduction) and IL-6 (increase) levels in normoglycemic (healthy), prediabetic (impaired fasting glucose), and hyperglycemic (diabetic) population in Indian population. There is a significant but gradual change during the progression of healthy toward diabetic population via pre-diabetic condition.

Adiponectin and risk of vascular events in the Northern Manhattan study

OBJECTIVES

Despite adiponectin's independent relationship with many markers of vascular disease risk, its association with clinical outcomes is unclear and results of studies have been inconsistent. We examined the association between adiponectin, an adipocytokine secreted by adipose tissue, and vascular events (stroke, myocardial infarction (MI), vascular death) in the multi-ethnic prospective population-based Northern Manhattan Study (NOMAS).

METHODS

Adiponectin was measured at baseline among 2900 participants free of MI and stroke (mean age 69 ± 10 years, 37% men, 21% white, 53% Hispanic, 24% black). Over a mean 10 years follow-up, 692 incident vascular events accrued.

RESULTS

The mean adiponectin = 11.4 ± 6.2 μg/ml (median = 9.8, range = 2.1-53.3). In Cox models adjusting for demographics and vascular risk factors, a decreased risk of vascular events was suggested with lower adiponectin. Examination of quartiles suggested a non-linear relationship, with a reduction in risk observed among those in adiponectin quartiles 1-3 vs. 4, and the lowest effect estimates observed in quartile 2. Similar results were found when stroke, MI, and vascular death were examined separately. We saw no effect modification by baseline vascular health profile, but the positive association between adiponectin and vascular events was stronger among those with elevated waist circumference.

CONCLUSIONS

In NOMAS, low-moderate adiponectin was associated with a decreased risk of vascular events despite the fact that low adiponectin levels were associated with an elevated vascular risk profile. These counter-intuitive findings underscore the need for further research on adiponectin as a useful biomarker of vascular disease risk and mechanisms explaining the inconsistent observations in the literature.