The association of leptin and C-reactive protein with the cardiovascular risk factors and metabolic syndrome score in Taiwanese adults

Effects of exercise training on inflammatory and cardiometabolic health markers in overweight and obese adults: a systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

The improvements in inflammation and cardiometabolic health play an important role in the prevention and treatment of obesity. However, the interactions between different exercise training (ET) modalities with inflammatory and cardiometabolic biomarkers are not completely understood. This systematic review and meta-analysis investigated the effects of ET on inflammatory and cardiometabolic health markers in overweight and obese adults.

EVIDENCE ACQUISITION

A systematic search was conducted in PubMed, CINAHL, MEDLINE, Cochrane, Google Scholar, Scopus and Web of Science up to December 15, 2021. Thirty-five studies including 2752 participants were included and analyzed using a random-effects model to estimate weighted mean differences (MD) with 95% confidence intervals (CI).

EVIDENCE SYNTHESIS

The meta-analysis found that ET significantly (P<0.05) increased adiponectin (WMD: 0.72 µg/mL; 95% CI: 0.60 to 0.84; SMD=0.65) and maximal oxygen consumption levels (WMD: 5.26 mL.kg.min; 95% CI: 3.84, 6.69; SMD=1.21). Moreover, ET significantly (P<0.05) reduced fasting insulin (WMD: -2.40 μIU/mL; 95% CI: -3.43 to -1.37; SMD=-0.87), fasting blood glucose (WMD: -5.41 mg/dL; 95% CI: -7.91, -2.91; SMD=-0.66), insulin resistance (WMD: -0.66; 95% CI: -1.08, -0.24; SMD=-0.66) and triglyceride levels (WMD: -10.88 mg/dL; 95% CI: -17.61, -4.15; SMD=-0.91). No significant changes were observed in interleukin-6, tumor necrosis factor-α, leptin, C-reactive protein and cholesterol concentrations. Subgroup analysis by type of training indicated that aerobic and resistance exercise had the most consistent beneficial effects as compared to other modalities.

CONCLUSIONS

Our findings suggest that ET may improve inflammation and cardiometabolic health in overweight and obese adults. Aerobic and resistance training appear to be more beneficial for improving adiponectin, fasting insulin, fasting blood glucose, insulin resistance index and triglyceride levels as compared to other exercise modalities. Further long-term studies are required to confirm and expand on these findings.

Blood and Urinary Biomarkers of Antipsychotic-Induced Metabolic Syndrome

Metabolic syndrome (MetS) is a clustering of at least three of the following five medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum high-density lipoprotein (HDL). Antipsychotic (AP)-induced MetS (AIMetS) is the most common adverse drug reaction (ADR) of psychiatric pharmacotherapy. Herein, we review the results of studies of blood (serum and plasma) and urinary biomarkers as predictors of AIMetS in patients with schizophrenia (Sch). We reviewed 1440 studies examining 38 blood and 19 urinary metabolic biomarkers, including urinary indicators involved in the development of AIMetS. Among the results, only positive associations were revealed. However, at present, it should be recognized that there is no consensus on the role of any particular urinary biomarker of AIMetS. Evaluation of urinary biomarkers of the development of MetS and AIMetS, as one of the most common concomitant pathological conditions in the treatment of patients with psychiatric disorders, may provide a key to the development of strategies for personalized prevention and treatment of the condition, which is considered a complication of AP therapy for Sch in clinical practice.

Magnesium Intake, C-Reactive Protein, and Muscle Mass in Adolescents

Background: Adult studies have suggested that magnesium intake may regulate C-reactive protein (CRP) and muscle mass, known risk factors for cardiometabolic diseases. Given the large deficiencies in magnesium intake in adolescents, we aimed to investigate sex and race differences in dietary magnesium intake and test the hypothesis that lower magnesium intake is associated with higher CRP and lower muscle mass. Methods: A total of 766 black and white adolescents, 14 to 18 years old (51% black; 50% female) were previously recruited. Diet was assessed with four to seven independent 24-h recalls. Body composition was measured by dual-energy X-ray absorptiometry. High-sensitivity CRP (hs-CRP), leptin, resistin, and adiponectin were measured using fasting blood samples by ELISA. Results: There were sex and race differences in the daily consumption of magnesium. The average daily magnesium intakes were 200.66 ± 7.09 mg and 205.03 ± 7.05 mg for males and females, respectively, far below the recommended amounts of 410 mg for males and 360 mg for females. White subjects (217.95 ± 6.81 mg/day) consumed more than black subjects (187.75 ± 6.92 mg/day). Almost none of the adolescents met the recommendations. Adjusted multiple linear regressions revealed that lower magnesium intake was associated with higher hs-CRP and lower fat-free mass (FFM) (p-values < 0.05). Higher hs-CRP was associated with lower FFM. Moreover, an interaction between magnesium intake and hs-CRP on FFM was identified (p-value < 0.05). Lower magnesium intake amplified the inverse relationships between hs-CRP and FFM (p-values < 0.05). Conclusion: Magnesium consumption in our adolescents was far below daily recommended levels with male and black subjects consuming less than female and white subjects. Lower magnesium intake was associated with higher CRP and lower muscle mass. Low magnesium intake may also augment the inverse relationship between CRP and FFM.

Impaired Sensitivity to Thyroid Hormones Is Associated With Elevated Blood Glucose in Coronary Heart Disease

CONTEXT

Thyroid hormones influence glucose homeostasis through central and peripheral regulation. To date, the association between thyroid hormone sensitivity and elevated blood glucose (EBG) in patients with coronary heart disease (CHD) remains unknown. The purpose of this study was to investigate the association between thyroid hormone sensitivity and risk of EBG in patients with CHD, and to further explore their association in different sexes and ages.

METHODS

This large multicenter retrospective study included 30,244 patients with CHD (aged 30-80 years) between 1 January 2014 and 30 September 2020. Parameters representing central and peripheral sensitivity to thyroid hormones were calculated. Central sensitivity to thyroid hormones was assessed by calculating the Thyroid Feedback Quantile-based Index (TFQI), Thyroid-stimulating Hormone Index (TSHI), and Thyrotropin Thyroxine Resistance Index (TT4RI), and Parametric Thyroid Feedback Quantile-based Index (PTFQI); peripheral sensitivity to thyroid hormones was evaluated using the ratio of free triiodothyronine (FT3) /free thyroxine (FT4). Taking normal glucose tolerance (NGT) as a reference, logistic regression was used to analyse the relationship between central and peripheral thyroid hormone sensitivity and EBG in patients with CHD.

RESULTS

Among the 30,244 participants, 15,493 (51.23%) had EBG. The risk of EBG was negatively correlated with TSHI (OR: 0.91; 95%CI: 0.91 to 0.92; P < 0.001), TT4RI (OR: 0.99; 95% CI: 0.99 to 0.99; P<0.001), TFQI (OR: 0.82; 95%CI: 0.80 to 0.84; P <0.001) and PTFQI (OR: 0.76; 95%CI: 0.74 to 0.78; P<0.001). Compared to males and patients aged 60 and below, the OR value for EBG was lower in females and in patients aged over 60 years old. Conversely, EBG risk was positively associated with FT3/FT4 (OR: 1.08; 95% CI: 1.07 to 1.09; P <0.001) and in the sex-categorized subgroups, males had higher OR values than females.

CONCLUSIONS

This study showed that thyroid hormone sensitivity is significantly associated with EBG in patients with CHD. This association is higher in females than in males, and the association in those aged over 60 years old is higher than that in patients aged 60 years and below.

Diagnostic Power of Circulatory Metabolic Biomarkers as Metabolic Syndrome Risk Predictors in Community-Dwelling Older Adults in Northwest of England (A Feasibility Study)

Background: Metabolic Syndrome (MetS) is a cluster of risk factors for diabetes and cardiovascular diseases with pathophysiology strongly linked to aging. A range of circulatory metabolic biomarkers such as inflammatory adipokines have been associated with MetS; however, the diagnostic power of these markers as MetS risk correlates in elderly has yet to be elucidated. This cross-sectional study investigated the diagnostic power of circulatory metabolic biomarkers as MetS risk correlates in older adults. Methods: Hundred community dwelling older adults (mean age: 68.7 years) were recruited in a study, where their blood pressure, body composition and Pulse Wave Velocity (PWV) were measured; and their fasting capillary and venous blood were collected. The components of the MetS; and the serum concentrations of Interleukin-6 (IL-6), Tumor Necrosis Factor-α (TNF-α), Plasminogen Activator Inhibitor-I (PAI-I), Leptin, Adiponectin, Resistin, Cystatin-C, C-Reactive Protein (CRP), insulin and ferritin were measured within the laboratory, and the HOMA1-IR and Atherogenic Index of Plasma (AIP) were calculated. Results: Apart from other markers which were related with some cardiometabolic (CM) risk, after Bonferroni correction insulin had significant association with all components of Mets and AIP. These associations also remained significant in multivariate regression. The multivariate odds ratio (OR with 95% confidence interval (CI)) showed a statistically significant association between IL-6 (OR: 1.32 (1.06–1.64)), TNF-α (OR: 1.37 (1.02–1.84)), Resistin (OR: 1.27 (1.04–1.54)) and CRP (OR: 1.29 (1.09–1.54)) with MetS risk; however, these associations were not found when the model was adjusted for age, dietary intake and adiposity. In unadjusted models, insulin was consistently statistically associated with at least two CM risk factors (OR: 1.33 (1.16–1.53)) and MetS risk (OR: 1.24 (1.12–1.37)) and in adjusted models it was found to be associated with at least two CM risk factors and MetS risk (OR: 1.87 (1.24–2.83) and OR: 1.25 (1.09–1.43)) respectively. Area under curve (AUC) for receiver operating characteristics (ROC) demonstrated a good discriminatory diagnostics power of insulin with AUC: 0.775 (0.683–0.866) and 0.785 by cross validation and bootstrapping samples for at least two CM risk factors and AUC: 0.773 (0.653–0.893) and 0.783 by cross validation and bootstrapping samples for MetS risk. This was superior to all other AUC reported from the ROC analysis of other biomarkers. Area under precision-recall curve for insulin was also superior to all other markers (0.839 and 0.586 for at least two CM risk factors and MetS, respectively). Conclusion: Fasting serum insulin concentration was statistically linked with MetS and its risk, and this link is stronger than all other biomarkers. Our ROC analysis confirmed the discriminatory diagnostic power of insulin as CM and MetS risk correlate in older adults.

Reduced concentrations of the B cell cytokine interleukin 38 are associated with cardiovascular disease risk in overweight subjects

The IL‐1 family member IL‐38 (IL1F10) suppresses inflammatory and autoimmune conditions. Here, we report that plasma concentrations of IL‐38 in 288 healthy Europeans correlate positively with circulating memory B cells and plasmablasts. IL‐38 correlated negatively with age (p = 0.02) and was stable in 48 subjects for 1 year. In comparison with primary keratinocytes, IL1F10 expression in CD19⁺ B cells from PBMC was lower, whereas cell‐associated IL‐38 expression was comparable. In vitro, IL‐38 is released from CD19⁺ B cells after stimulation with rituximab. Intravenous LPS in humans failed to induce circulating IL‐38, compared to 100‐fold induction of IL‐6 and IL‐1 receptor antagonist. In a cohort of 296 subjects with body mass index > 27 at high risk for cardiovascular disease, IL‐38 plasma concentrations were significantly lower than in healthy subjects (p < 0.0001), and lowest in those with metabolic syndrome (p < 0.05). IL‐38 also correlated inversely with high sensitivity C‐reactive protein (p < 0.01), IL‐6, IL‐1Ra, and leptin (p < 0.05). We conclude that a relative deficiency of the B cell product IL‐38 is associated with increased systemic inflammation in aging, cardiovascular and metabolic disease, and is consistent with IL‐38 as an anti‐inflammatory cytokine.

Leptin concentrations in type 2 diabetes and non-diabetes Nigerian-Africans

Most studies on leptin in diabetes mellitus (DM) compared to healthy controls were done in Caucasians, with conflicting findings. Paucity of data on this exists in Nigerian-Africans. Therefore, the study determined plasma leptin concentrations in newly diagnosed type-2 diabetes versus controls and its relation to obesity/demographic-metabolic indices. A cross-sectional comparative study on 154 subjects: 67 diabetes and 87 healthy controls at the Ahmadu Bello University Teaching Hospital, Nigeria. Leptin was determined by the sandwich enzyme-linked immunosorbent assay. Mann-Whitney U test, Spearman's Correlation and Step-wise Multiple Logistic Regression analysis of Log-transformed variables determined outcomes. Leptin trended towards lower levels in DM subjects than controls when both sexes were combined, though insignificant (P=0.12). Leptin was significantly (P<0.001) positively correlated with waist circumference (WC) and body mass index (BMI) in DM (WC, r=0.71; BMI, r=0.84) as well as controls (WC, r=0.46, BMI, r=0.51), respectively. Leptin was significantly (P<0.001) higher in females than males, with approximately 2 times Odds of female sex association with log-transformed (Ln₁₀) hyperleptinaemia {Odds Ratio (OR): 1.9, 95% CI, 0.97-3.92, P<0.001}. Age was positively (r=0.21, P=0.05) correlated to leptin in controls, while fasting blood glucose (FBG) negatively correlated to uncontrolled DM (r=-0.26). Leptin showed no significant (P>0.05) correlation to fasting insulin (FI) and HOMA-IR. WC was an independent predictor of Ln₁₀hyperleptinaemia in DM subjects (OR: 1.12, 95% CI, 1.03-1.23, P=0.01). BMI showed significant (P<0.001) association with Ln₁₀hyperleptinaemia in both subjects. Conclusively, leptin trends towards lower levels but are not different in newly diagnosed DM than controls. The association of leptin with obesity is similar but stronger in diabetes than controls, with no relations to FI and HOMA-IR. WC and BMI are independent predictors of hyperleptinaemia.

An update on the association between metabolic syndrome and osteoarthritis and on the potential role of leptin in osteoarthritis

Metabolic syndrome (MetS) has been associated with osteoarthritis (OA). Leptin, which is one of the markers of MetS, has been associated with OA pathophysiology. This study aimed to provide an update on the association between MetS and OA and on the potential role of leptin in OA. In this review, we summarized the current knowledge of the association between MetS and OA and updated the evidence on the potential role of leptin in OA. Clinical studies have investigated the epidemiologic association between MetS or its components and OA. Results suggested strong epidemiologic associations between MetS and OA, especially in the Asian population. Animal studies also indicated that metabolic dysregulation may lead to OA pathogenesis. The systemic role of MetS in OA pathophysiology is associated with obesity-related inflammation, the beneficial role of n-3 polyunsaturated fatty acids and deleterious role of cholesterol, physical inactivity, hypertension-induced subchondral ischemia, dyslipidemia-induced ectopic lipid deposition in chondrocytes, hyperglycemia-induced local effects of oxidative stress and advanced glycation end-products, low-grade systemic inflammation, and obesity-related adipokines by inducing the expression of proinflammtory factors. Leptin levels in serum/plasma and synovial fluid were associated with joint pain, radiographic progression, bone formation biomarkers, cartilage volume, knee OA incidence, and total joint arthroplasty in OA patients. Elevated leptin expression and increased effect of leptin on infrapatellar fat pad, synovium, articular cartilage, and bone were also involved in the pathogenesis of OA. Current knowledge indicates a convincing epidemiologic association between MetS and OA, especially in the Asian population. Animal studies have also shown that metabolic dysregulation may lead to OA pathogenesis. Accumulating evidence suggests that leptin may play a potential role in OA pathogenesis. Therefore, leptin and its receptor may be an emerging target for intervention in metabolic-associated OA.

High-Sensitivity C-Reactive Protein Leads to Increased Incident Metabolic Syndrome in Women but Not in Men: A Five-Year Follow-Up Study in a Chinese Population

PURPOSE

Metabolic syndrome (MetS), characterized by a constellation of insulin resistance, central obesity, hypertension, and hyperlipidemia, is a global health threat. High-sensitivity C-reactive protein (hs-CRP) has been shown to be associated with type 2 diabetes and cardiovascular disease; however, its association with incident MetS is less known. Therefore, the aim of this study was to examine the prospective association between hs-CRP and MetS among a Chinese population in a 5-year follow-up study.

PATIENTS AND METHODS

The levels of hs-CRP were measured using serum samples collected at baseline recruitment in 2012 from 886 participants without MetS. Follow-up interviews were conducted in 2018, and MetS was diagnosed by 2017 criteria from the Chinese Diabetes Society. Multivariate logistic regression models were used to assess the overall and sex-specific associations between hs-CRP and incident MetS. The odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were computed with adjustment for demographic, socioeconomic, clinical, and lifestyle factors.

RESULTS

After a mean follow-up duration of 5.40 ± 0.56 years, 116 (13.3%) participants developed MetS. In the total study population, increased hs-CRP levels were associated with a higher risk of MetS (OR comparing extreme quartiles of hs-CRP: 4.06 [95% CI: 1.91-8.65]) in the fully-adjusted model. When stratified by sex, the positive association was only observed in women (OR: 4.82 [1.89-12.3]) but not in men (OR: 3.15 [0.82-12.1]; P-interaction = 0.039).

CONCLUSION

In this study of a Chinese population, a positive association between hs-CRP and incident MetS was found only in women and not in men. Sex-specific prediction and intervention of MetS using hs-CRP as a target should be further evaluated.

The influence of the TNFα rs1800629 polymorphism on some inflammatory biomarkers in 45-60-year-old women with metabolic syndrome

Introduction: There are reports that the TNFα gene (rs1800629) can be involved in the pathogenesis of metabolic syndrome through an increased production of pro-inflammatory cytokines. Therefore, we have decided to search for the relationship between the TNFα gene polymorphisms and serum levels of proinflammatory cytokines (IL-1α, IL-1β, IL-6, TNFα, IFNγ) and CRP in women with metabolic syndrome.

Material and methods: The study sample consisted of 416 women aged 45-60 years, including 118 with metabolic syndrome. The participants were surveyed and subjected to anthropometric, biochemical and genetic analysis.

Results: We noticed that in the group meeting the criteria for metabolic syndrome, the G/G genotype of the TNFα gene was related to higher IL-6 levels than in the remainder group. The carriers of the A/G genotype in the metabolic syndrome group had significantly higher levels of IFNγ than those in the group without this syndrome. CRP was significantly higher in the group with metabolic syndrome, irrespective of the women’s genotypes.

Conclusions: The upregulation of IFNγ and IL-6 and CRP suggests that autoinflammatory process may play a significant role in the pathogenesis of metabolic syndrome. However, a direct relationship between the TNFα gene polymorphisms and inflammatory biomarkers analyzed in our study was not confirmed.

Association between hyperleptinemia and cardiovascular outcomes in patients with coronary artery disease

Purpose

Hyperleptinemia has been independently associated with human cardiovascular (CV) diseases. Accordingly, we evaluate the association between serum leptin and future CV events in patients with coronary artery disease (CAD).

Patients and methods

This study enrolled 98 patients with CAD from January to December 2012. The primary endpoint included incidences of major adverse CV events and hospitalization. Patients follow-up had been completed on June 30, 2017.

Results

After a median follow-up of 52 months, 43 CV events had occurred. Patients with CV events had higher systolic blood pressure (P = 0.030), total cholesterol (P = 0.034), C-reactive protein (P = 0.018), and serum leptin levels (P = 0.001) than those without CV events. Kaplan–Meier analysis showed greater cumulative incidences of CV events in the high leptin group (median leptin concentration >6.03 ng/mL) than in the low leptin group (log-rank P = 0.012). Multivariate Cox regression analysis showed that triglyceride (HR: 1.010; 95% CI: 1.001–1.018; P = 0.022) and leptin levels (HR: 1.054; 95% CI: 1.026–1.082; P < 0.001) were independently associated with CV events in patients with CAD.

Conclusion

Serum leptin levels could serve as a biomarker for future CV events in patients with CAD.

The Association of Serum Leptin Level and Anthropometric Measures With the Severity of Diabetic Retinopathy in Type 2 Diabetes Mellitus

This study was performed to determine the association amongst serum leptin level and anthropometric measures with the severity of Diabetic Retinopathy (DR) in subjects with type 2 Diabetes Mellitus (DM). This case-controlled study was conducted within a one-year period, during year 2016, at outpatient retina ophthalmology clinics of Shiraz, southern Iran. Eighty-three patients with type 2 DM, referring for ophthalmoscopy evaluation, were included. Anthropometric measures, serum leptin level, and baseline laboratory assessment was performed for all subjects. Patients were categorized as group 1, consisting of patients with severe Non-Proliferative Diabetic Retinopathy (severe NPDR) and Proliferative Diabetic Retinopathy (PDR) (n = 44), and group 2, consisting of patients without Diabetic Retinopathy (no DR) or mild/moderate NPDR (n = 39). The serum leptin level and anthropometric measures were compared between the two study groups. The correlation between these variables was also assessed. The mean age of the participants was 59.3 ± 6.9 years old. The two study groups were comparable regarding baseline characteristics. Cases of group 1 had significantly higher Erythrocyte Sedimentation Rate (ESR) (P = 0.049) and Systolic Blood Pressure (P = 0.025) when compared with those of group 2. The serum level of leptin was found to be significantly higher in cases of group 1 when compared to those of group 2 (P = 0.003). However, anthropometric measures, including Body Mass Index (BMI) (P = 0.167), Body Adiposity Index (BAI) (P = 0.061), and Waist to Hip Ratio (WHR) (P = 0.220) were comparable between the two study groups. Serum leptin level was positively correlated with BMI (r = 0.819; P < 0.001) and BAI (r = 0.630; P < 0.001) in group 1. Increased serum levels of leptin were associated with advanced stages of DR in subjects with type 2 DM. Serum leptin level might be a better indicator of the effects of obesity on DR, compared to anthropometric measures (BAI or BMI).

The association of vaspin rs2236242 and leptin rs7799039 polymorphism with metabolic syndrome in Egyptian women

BACKGROUND/AIM

Genetic predisposition is implicated in the etiology of metabolic syndrome. This study aimed to investigate the1397645907association of vaspin rs2236242 and leptin rs7799039 polymorphisms with their serum levels and with the risk of developing metabolic syndrome in Egyptian women.

MATERIALS AND METHODS

This case control study included 100 Egyptian women with metabolic syndrome and 100 without metabolic syndrome. The genotypes of vaspin rs2236242 and leptin rs7799039 were detected by a methodology based on PCR-RFLP. Serum vaspin and leptin levels were determined by ELISA.

RESULTS

The metabolic syndrome group was associated with higher serum vaspin and leptin levels when compared to the nonmetabolic syndrome group. The AA genotype of leptin rs7799039 was associated with metabolic syndrome and with higher serum leptin levels, while the different genotypes of vaspin rs2236242 were not associated with metabolic syndrome or different serum vaspin levels.

CONCLUSION

The AA genotype of leptin rs7799039 was associated with metabolic syndrome and higher serum leptin levels. Serum leptin and vaspin can be used as diagnostic markers of metabolic syndrome.

Metabolic Syndrome Patients Have Lower Levels of Adropin When Compared With Healthy Overweight/Obese and Lean Subjects

Metabolic syndrome (MetS), a cluster of cardiometabolic risk factors, is a challenging public health issue. The aim of current study was to test the hypothesis that concentrations of plasma adropin and leptin differ between patients with MetS and comparable age- and sex-matched control groups. This case-control study involved 153 subjects (51 per group). The study group included obese subjects with MetS and the two control groups included weight-matched subjects without MetS ("healthy": obese) and normal weight subjects without MetS. Body composition parameters were measured using bioelectrical impedance analysis. Plasma levels of adropin, leptin, and their ratio were measured. Leptin was significantly different between obese patients with/without MetS groups and normal weight subjects. Patients with MetS had higher levels of leptin (14 ± 12.4) compared with those without MetS (11.2 ± 9.3 vs. 7 ± 7.1 obese and normal weight without MetS, respectively; p = .002). Compared with healthy obese and normal weight subjects, MetS subjects had lower levels of plasma adropin ( p < .001) and a lower plasma adropin to leptin ratio ( p < .001), which remained significant when adjusted for body fat mass by analysis of covariance ( p < .001). This study demonstrates low levels of adropin are correlated with MetS and hence identify it as a potentially protective agent against MetS development. Variation in adropin levels may partly explain the "healthy obese" phenomenon.

Relationship between serum leptin and insulin resistance among obese Nigerian women

Background:

Leptin is a hormone produced directly from adipocytes and has been associated with type 2 diabetes mellitus (T2DM) which is characterized by insulin resistance (IR). Due to the increasing prevalence of obesity in sub-Saharan Africa, serum leptin can be explored as a predictive risk factor for T2DM. Therefore, the aim of this study was to determine the relationship between serum leptin and IR among obese women.

Methods:

This was a cross-sectional study of obese, adult Nigerian females. Participants with body mass index (BMI) ≥30 kg/m² and nondiabetic were recruited as subjects. Fasting serum leptin, insulin, and plasma glucose were determined. IR was calculated using the formula: Homeostatic model assessment-IR (HOMA-IR) = (glucose × insulin)/22.5. Statistical analyses were performed using SPSS and P < 0.05 was considered to be significant.

Results:

Eighty obese females with mean ± standard deviation BMI 39.1 ± 7.2 kg/m² and serum leptin level 48.4 ± 24.4 ng/ml participated in study. Prevalence of hyperleptinemia was 92.5% (confidence interval: 87.3–97.7%). The relationship between leptin and HOMA-IR among the subjects was: BMI 30–34.9 kg/m²: n = 27, r = 0.18, P = 0.42; BMI 35–39.9 kg/m²: n = 24, r = 0.36, P = 0.11; BMI ≥ 40 kg/m²: n = 29, r = 0.52, P = 0.004*; and after controlling for BMI (n = 29, r = 0.46, P = 0.014*). Multiple linear regression showed that leptin did not predict for IR (P = 0.837).

Conclusion:

Serum leptin levels were positively correlated with IR, which was significant among the Class III (morbid) obesity class. However, leptin was not a predictive factor for IR in obese Nigerian women.

Biomarkers of Metabolic Syndrome: Biochemical Background and Clinical Significance

Biomarkers of the metabolic syndrome are divided into four subgroups. Although dividing them in groups has some limitations, it can be used to draw some conclusions. In a first part, the dyslipidemias and markers of oxidative stress are discussed, while inflammatory markers and cardiometabolic biomarkers are reviewed in a second part. For most of them, the biochemical background and clinical significance are discussed, although here also a well-cut separation cannot always be made. Altered levels cannot always be claimed as the cause, risk, or consequence of the syndrome. Several factors are interrelated to each other and act in a concerted, antagonistic, synergistic, or modulating way. Most important conclusions are summarized at the end of every reviewed subgroup. Genetic biomarkers or influences of various food components on concentration levels are not included in this review article.

Clinical and Biochemical Markers of Cardiovascular Structure and Function in Women With the Metabolic Syndrome

The pathobiological impact of individual components of the metabolic syndrome (MS) on cardiac structural and functional parameters in women with isolated MS is not known. The objectives of this study were (1) to compare biochemical (prothrombotic, lipogenic, and inflammatory) and imaging (carotid intima-media thickening and basic cardiac structural measurements) markers in women with and without MS and (2) to examine if any of these markers associated or predicted cardiac structural differences between the 2 groups. This cross-sectional pilot study included 88 women with MS and 35 women without it. MS was defined according to the National Cholesterol Education Program Adult Treatment Panel III criteria. Patients with diagnosis of diabetes were excluded. Compared with healthy subjects, women with MS had higher levels of intercellular adhesion molecule, myeloperoxidase, C-reactive protein, plasminogen activator inhibitor-1, leptin, apolipoprotein-B, and lower levels of apolipoprotein-A1 (p <0.001 for all). They also had higher mean ventricular septum, posterior wall thickness, left ventricular (LV) mass, carotid intima-media thickness (p <0.001 for all), and left atrial diameter (p = 0.015). In multivariable regression models, waist circumference and systolic blood pressure (BP) were significant predictors of: ventricular septum (p = 0.005 and p = 0.001, respectively), posterior wall thickness (p = 0.008 and p = 0.040, respectively), and LV mass (p <0.001 and p = 0.013, respectively). Significant predictors for carotid intima-media thickness were systolic BP, glucose, and leptin (p <0.0001, p = 0.034, and p = 0.002, respectively). In conclusion, there are significant clinical, biochemical, and cardiovascular structural differences in women with isolated MS compared with those without. Waist circumference and systolic BP had the strongest association with cardiac structural differences in this group of women.

Is osteoarthritis a metabolic disorder?

BACKGROUND

Obesity is associated with an increased risk of developing osteoarthritis (OA), even in non-weight bearing joints. High levels of adipose tissue-associated inflammation may explain this association.

SOURCES OF DATA AND AREAS OF DEBATE

Published evidence looking at the associations between components of Metabolic Syndrome (MetS) and knee, hip or hand OA and the higher mortality described with knee OA.

EMERGING POINTS

Development of MetS and OA shares a relationship with adipose tissue-associated inflammation. This review supports this inflammatory pathway being part of the shared mechanism behind obesity as a risk factor for OA and the recently described OA-associated increased mortality.

TIMELY AREAS FOR DEVELOPMENT

In an era of an obesity epidemic, this review identifies a need for well-designed cohort studies assessing early metabolic changes in populations at high risk of OA and MetS, and to identify risk factors for increased mortality in patients with OA.

Favorable Levels of All Major Cardiovascular Risk Factors at Younger Ages and High-Sensitivity C-Reactive Protein 39 Years Later -The Chicago Healthy Aging Study

Objectives

Examine associations of favorable levels of all cardiovascular disease (CVD) risk factors (RFs) [i.e., low risk (LR)] at younger ages with high sensitivity C-reactive protein (hs-CRP) at older ages.

Methods

There were 1324 participants ages 65–84 years with hs-CRP ≤ 10 mg/L from the Chicago Healthy Aging Study (2007–2010), and CVD RFs assessed at baseline (1967–73) and 39 years later. LR was defined as untreated blood pressure (BP) ≤ 120/≤ 80 mm Hg, untreated serum total cholesterol < 200 mg/dL, body mass index (BMI) < 25 kg/m², not smoking, and no diabetes. Hs-CRP was natural log-transformed or dichotomized as elevated (≥ 3 mg/L or ≥ 2 mg/L) vs. otherwise.

Results

With multivariable adjustment, the odds ratios (95% confidence intervals) for follow-up hs-CRP ≥ 3 mg/in participants with baseline 0 RF, 1 RF and 2 + RFs compared to those with baseline LR were 1.35 (0.89–2.03), 1.61 (1.08–2.40) and 1.69 (1.04–2.75), respectively. There was also a graded, direct association across four categories of RF groups with follow-up hs-CRP levels (β coefficient/P-trend = 0.18/0.014). Associations were mainly due to baseline smoking and BMI, independent of 39-year change in BMI levels. Similar trends were observed in gender-specific analyses.

Conclusions

Favorable levels of all CVD RFs in younger age are associated with lower hs-CRP level in older age.

Clinical analysis of the relationship between cystatin C and metabolic syndrome in the elderly

OBJECTIVE

Studies have shown that both cystatin C and metabolic syndrome (MetS) are associated with inflammation. We set out to investigate the correlation between serum cystatin C levels and MetS in the elderly.

METHODS

This prospective study was conducted in 380 elderly individuals, including 135 patients with MetS, 142 patients with metabolic disturbance (MetD), and 103 healthy elderly individuals (control group). Waist-hip ratio, waist circumference, waist-height ratio, body mass index (BMI), fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), high-density lipoprotein (HDL-C), systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure and cystatin C were measured and their mutual relations were analyzed.

RESULTS

The higher the MetS scores, the higher the serum cystatin C concentration in these patients. Serum cystatin C concentration was closely related to waist-hip ratio, waist circumference, waist-height ratio, BMI, TG, FPG, and blood pressure, not related to LDL-C levels, and negatively correlated with HDL-C levels. Logistic regression analysis indicated that cystatin C, waist-height ratio, waist circumference, FPG, TG, SBP and pulse pressure were significantly associated with MetS (OR between cystatin C and MetS 2.164, 95% CI 1.136-8.259).

CONCLUSION

Cystatin C was significantly associated with MetS in the elderly. As MetS scores rose, serum cystatin C levels increased.

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.

Association between inflammatory biomarkers and adiposity in obese patients with heart failure and metabolic syndrome

Obesity, type 2 diabetes mellitus (DM) and metabolic syndrome (MS) are common in patients with heart failure (HF). Studies investigating the association between known biomarkers and adiposity in patient populations are limited. The aim of the present study was to investigate the association between C-reactive protein (CRP) and leptin with adiposity in a sub-group of overweight/obese patients with HF, DM and/or MS. A total of 36 patients (mean age, 56.72±9.78 years; ranging between 27 and 76 years of age; 80.6% male; 52.8% Caucasian) were enrolled and their height, weight, waist circumference and body composition (e.g. percentage body fat and lean mass), as well as the levels of CRP and leptin, were assessed. The results demonstrated that there was a significant association between CRP and leptin, CRP and body mass index (BMI) and gender and percentage body fat (P<0.05, for all associations). Analysis of leptin and CRP levels revealed that patients in the highest BMI quartile (BMI, 40.3-61.2) had higher CRP levels (4.83 μg/ml vs. 3.03 μg/ml; P=0.033) and higher leptin levels (44.97 ng/ml vs. 24.64 ng/ml; P=0.042) compared with patients in the lower BMI quartile (BMI, 28.6-32.4). In conclusion, among obese patients with HF, DM and/or MS, an association between CRP and leptin was identified, providing further evidence that metabolic and inflammatory mechanisms are involved in these diseases. Future investigation to assess the potential impact of inflammation and adiposity, and the role of dietary interventions and weight loss on clinical outcomes in this population of chronically ill patients is warranted.

Adipokines, metabolic syndrome and rheumatic diseases

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

Comparison of salivary and plasma adiponectin and leptin in patients with metabolic syndrome

BACKGROUND

The relationship of saliva with plasma protein levels makes saliva an attractive diagnostic tool. Plasma levels of adiponectin and leptin in healthy individuals or diabetes mellitus patients have been previously reported. Nevertheless, salivary levels of these adipocytokines in patients with metabolic syndrome (MS) have never been investigated. This study was aimed to determine adiponectin and leptin levels in saliva and plasma from patients with metabolic syndrome, and evaluate any correlation of these levels with MS.

METHODS

Forty-six healthy and 82 MS patients were enrolled. Demographic data and blood biochemistries were recorded. Saliva and plasma adiponectin and leptin levels were analyzed by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Adiponectin and leptin were higher in plasma than in saliva (p < .001). Plasma adiponectin was decreased and plasma leptin increased in patients with MS (p < .001). Salivary adiponectin and salivary leptin were not different between healthy subjects and MS patients (p = .619 and p = .523). Correlation between salivary and plasma adiponectin showed significant association (r = .211, p = .018) while salivary and plasma leptin had no correlation (r = -.161, p = .069). Significant correlation was observed between the salivary adiponectin/salivary leptin ratio and plasma adiponectin (r = .371, p < .001), but not with any component of MS. Increased triglyceride and waist circumference were associated with risk of having a low level of plasma adiponectin (OR = 1.009; 95% CI 1.002-1.015 and OR = 1.125; 95% CI 1.029-1.230). For leptin, body mass index and high-density lipoprotein cholesterol (HDL-C) were associated with a high level of plasma leptin (OR = 1.621; 95% CI 1.212-2.168 and OR = .966; 95% CI .938-.996). The OR for MS as predicted by plasma adiponectin was .928 (95% CI .881-.977).

CONCLUSIONS

This study showed that salivary adiponectin and leptin do not correlate with MS. Although correlation between salivary and plasma adiponectin was observed, no association with MS was observed. Only plasma adiponectin may be useful for the prediction of MS.

Leptin is associated with vascular endothelial function in overweight patients with type 2 diabetes

BACKGROUND

The adipocyte-derived hormone leptin plays a key role in the regulation of appetite and body weight. Recent studies have suggested that leptin is also involved in the pathogenesis of obesity-related atherosclerosis and cardiovascular disease. In this study, we investigated the association of plasma leptin levels with vascular endothelial function in lean and overweight patients with type 2 diabetes.

METHODS

One hundred seventy-one type 2 diabetic patients, of which 85 were overweight (body mass index (BMI) ≥ 25 kg/m2), were enrolled in this cross-sectional study. Plasma leptin concentrations were measured by enzyme-linked immunosorbent assay. Flow-mediated dilatation (FMD) of the brachial artery was measured to evaluate vascular endothelial function using ultrasound.

RESULTS

No significant difference in FMD was found between the lean and overweight groups (7.0 ± 3.8% and 6.5 ± 3.6%, respectively; p = 0.354). FMD was negatively correlated with age (r = -0.371, p < 0.001) and serum creatinine levels (r = -0.236, p = 0.030), but positively correlated with BMI (r = 0.330, p = 0.002) and plasma leptin levels (r = 0.290, p = 0.007) in the overweight group. FMD was not associated with any parameters in the lean group. Multiple regression analysis including possible atherosclerotic risk factors revealed that the plasma leptin level (β = 0.427, p = 0.013) was independently associated with FMD in the overweight group (R2 = 0.310, p = 0.025), but not the lean group.

CONCLUSION

Plasma leptin levels are associated with vascular endothelial function in overweight patients with type 2 diabetes.

Short duration of sleep is associated with hyperleptinemia in Taiwanese adults

BACKGROUND

Higher plasma levels of leptin have been associated with increased cardiometabolic risk. The aim of this study was to investigate the association between short duration of sleep and hyperleptinemia in Taiwanese adults.

METHODS

We examined the association between duration of sleep and hyperleptinemia in 254 men and women recruited from the physical examination center at a regional hospital in southern Taiwan. Hyperleptinemia was defined as a plasma leptin level of 8.13 ng/mL and above. Short sleep duration was defined as < 6.5 h/day. Multiple logistic regression analysis was used to assess the association between short duration of sleep and hyperleptinemia.

RESULTS

In females, short duration of sleep (< 6.5 h/day; OR = 2.15, 95% CI = 0.99-4.78), greater hip circumference (OR = 3.00, CI = 1.13-8.78), higher percent body fat (OR = 1.75, CI = 1.07-2.95), and higher white blood cell counts (OR = 1.67, CI = 1.26-2.28) were associated with an increased risk of hyperleptinemia. In males, greater body weight was significantly associated with an increased risk of hyperleptinemia (OR = 3.55, 95% CI = 1.46-10.23). There was also a trend of association (p = 0.096) between short duration of sleep and an increased risk of hyperleptinemia (OR = 4.98, 95% CI = 0.80-42.40).

CONCLUSIONS

In this study of healthy Taiwanese adults, short duration of sleep was significantly associated with hyperleptinemia in women, and the association was independent of adiposity.

Leptin's activity on the hydroxyl radical: a possible link to the oxidative stress-related endothelial vasodilation in patients with obstructive sleep apnea

PURPOSE

Obstructive sleep apnea (OSA) is associated with increased cardiovascular morbidity, whereas the underlying mechanism is still eluding, the thought participants are chronic intermittent hypoxia with consequent increase in the reactive oxygen species, leading to endothelial cell damage and dysfunction in these patients. As the hydroxyl radical (·OH) mediates the vascular smooth muscle relaxation, identification of its scavengers might reveal sentinel markers of decreased vascular responsiveness and worse long-term comorbid outcome. We therefore assessed leptin's scavenger effect on (∙)OH using the electronic paramagnetic resonance (EPR) method.

METHODS

The (∙)OH was generated by the Fenton reaction in the presence of spin-trap 5-diethoxyphosphoryl-5-methyl-1-pyrroline N-oxide (DMPO) with various concentrations of leptin (0.25, 2.5, and 25 μg/ml) and without leptin. EPR spectrometer settings were: modulation frequency, 100 kHz; X band microwave frequency, 9.5 GHz; microwave power, 20 mW (milliwatts); modulation amplitude, 1.0 G (gauss); time constant, 160 s; scan time, 200 s; and receiver gain, 1 × l0(5). EPR signal intensity between 3,440 and 3,540 G of measurements taken in at least three separate experiments was reported. Mannitol, a known (∙)OH scavenger, at 100 mM significantly decreased the DMPO-OH adduct formation and was used as the active-control agent.

RESULTS

Leptin added to aqueous solutions at all concentrations was associated with a statistically significant decrease in EPR signal compared with controls due to its scavenging activity towards the ·OH.

CONCLUSIONS

Leptin could be further investigated as a sentinel biomarker of decreased vascular responsiveness and future risk of atherosclerotic disease in obese OSA patients.

Latent associations of low serum amylase with decreased plasma insulin levels and insulin resistance in asymptomatic middle-aged adults

Background

Low serum amylase is likely to be associated with obesity and metabolic abnormalities, which are often accompanied by impaired insulin action. However, it is unclear whether low serum amylase is associated with impaired insulin action in clinical settings. Therefore, we investigated the associations of low serum amylase with plasma insulin levels, and obesity-related parameters, including leptin.

Research design and methods

We measured serum amylase, plasma insulin, obesity-related parameters such as leptin, cardiometabolic risk factors, and anthropometric parameters in a cross-sectional study of 54 asymptomatic subjects (mean age 48.6 ± 7.6 years) who were not being treated for diabetes.

Results

Body mass index (BMI) and plasma glucose at 120 min after a 75-g oral glucose tolerance test (OGTT) were significantly higher in subjects with low serum amylase (< 60 IU/l, n = 21) than in those with normal-to-high serum amylase (n = 33) (P = 0.04 and P = 0.004, respectively). In univariate correlation analysis, serum amylase was significantly correlated with BMI alone (r = –0.39, P = 0.004). By contrast, multivariate logistic analysis showed that each 1-SD increase in quantitative insulin sensitivity check index, and each 1-SD decrease in plasma insulin OGTT at 0 and 60 min, homeostasis model assessment of insulin resistance (HOMA)-R, and HOMA-β were significantly associated with low serum amylase, particularly after adjusting for BMI. When subjects were divided into three groups according to HOMA-R, serum amylase levels were significantly lower in subjects with HOMA-R > 2.5 (n = 23) compared with subjects with HOMA-R 1.6–2.5 (n = 10) (61.1 ± 13.6 U/ml versus 76.9 ± 20.5 U/ml, Bonferroni test, P = 0.02), but not compared with subjects with HOMA-R<1.6 (n = 21; 62.7 ± 17.6 U/ml). Similar trends were observed when subjects were divided according to plasma leptin and fasting plasma insulin levels.

Conclusions

These results suggest that after adjusting for BMI, low serum amylase is associated with decreased basal insulin levels and insulin secretion, as well as high insulin resistance. The nature of these associations remains to be elucidated in further studies.