Leptin levels predict the development of insulin resistance in a sample of adult men–The Olivetti Heart Study

Background and aims

Leptin (LPT) is associated with unfavourable cardio-metabolic risk profile. Although a number of studies have found a positive association between LPT and insulin resistance (IR), no observational study has evaluated a prospective association to detect a predictive role of LPT in IR. Therefore, the aim of this study was to estimate the role of LPT on the incidence of IR in an 8-year follow-up of a sample of adult men (The Olivetti Heart Study).

Coronary artery calcifications and diastolic dysfunction versus visceral fat area in type 1 diabetes: VISCERA study

Aims

Type 1 diabetic patients (T1DM) experience a higher cardiovascular disease and mortality risk than controls. We investigated whether visceral adipose tissue (VAT) contributes to coronary artery calcifications (CAC) and cardiac dysfunction in T1DM.

Increased level of resistin predicts development of atrial fibrillation

BackgroundResistin is a peptide hormone that is secreted from lipid cells and is linked to type-2 diabetes, obesity, and inflammation. Being an important adipocytokine, resistin was proven to play an important role in cardiovascular disease. We compared resistin levels in patients with and without atrial fibrillation (AF) to demonstrate the relationship between plasma resistin levels and AF.MethodOne hundred patients with AF and 58 control patients who were matched in terms of age, gender, and risk factors were included in the trial. Their clinical risk factors, biometric measurements, echocardiographic work up, biochemical parameters including resistin and high-sensitivity C-reactive protein (hs-CRP) levels were compared.ResultsIn patients with AF, plasma resistin levels (7.34 ± 1.63 ng/mL vs 6.67 ± 1.14 ng/mL; p = 0.003) and hs-CRP levels (3.01 ± 1.54 mg/L vs 2.16 ± 1.28 mg/L; p = 0.001) were higher than control group. In subgroup analysis, resistin levels were significantly higher in patients with paroxysmal (7.59 ± 1.57 ng/mL; p = 0.032) and persistent AF (7.73 ± 1.60 ng/mL; p = 0.006), but not in patients with permanent AF subgroups (6.86 ± 1.61 ng/mL; p = 0.92) compared to controls. However, hs-CRP levels were significantly higher only in permanent AF patients compared to control group (3.26 ± 1.46 mg/L vs 2.16 ± 1.28 mg/L; p = 0.02). In multivariate regression analysis using model adjusted for age, gender, body mas index, hypertension, diabetes mellitus, and creatinine levels, plasma resistin levels [odds ratio (OR): 1.30; 95% confidence interval (CI): 1.01–1.70; p = 0.04] and hs-CRP levels (OR: 1.44; 95% CI: 1.12–1.86; p = 0.004) were the only independent predictors of AF.ConclusionThe elevated levels of plasma resistin were related to paroxysmal AF group and persistent AF group, but not to permanent AF group.     

Effects of dairy products consumption on inflammatory biomarkers among adults: A systematic review and meta-analysis of randomized controlled trials

AimsThis study aimed to summarize earlier studies on the effects of dairy consumption on inflammatory biomarkers in adults and to quantify these effects through meta-analysis.Data synthesisA comprehensive search of all relevant articles, published up to December 2019 indexed in PubMed, ISI (Institute for Scientific Information), EmBase, Scopus, and Google Scholar was done using relevant keywords. Randomized controlled trials (RCTs) that examined the effect of dairy products consumption, compared with low or no dairy intake, on inflammatory biomarkers in adults were included. Overall, 11 RCTs with 663 participants were included in this meta-analysis. We found that high consumption of dairy products, compared with low or no dairy intake, might significantly reduce CRP [weighed mean difference (WMD): −0.24 mg/L; 95% CI, −0.35, −0.14], TNF-α (WMD:- 0.66 pg/mL; 95% CI, −1.23, −0.09), IL-6 (WMD: −0.74 pg/mL; 95% CI, −1.36, −0.12), and MCP concentrations (WMD: −25.58 pg/mL; 95% CI, −50.31, −0.86). However, when the analyses were confined to cross-over trials, no such beneficial effects of dairy intake on inflammation were observed. In addition, high dairy intake might result in increased adiponectin levels (WMD: 2.42 μg/mL; 95% CI, 0.17, 4.66). No significant effect of dairy consumption on serum leptin (WMD: −0.32 ng/mL; 95% CI, −3.30, 2.65), ICAM-1 (WMD: −3.38 ng/ml; 95% CI, −15.57, 8.96) and VCAM-1 (WMD: 3.1 ng/mL; 95% CI, −21.38, 27.58) levels was observed.ConclusionsIn summary, the current meta-analysis indicated that dairy intake might improve several inflammatory biomarkers in adults. In most subgroups without heterogeneity, effects tended to be null. Study design and participants’ age were the main sources of heterogeneity. More research, with a particular focus on fat content of dairy foods, is recommended.     

Association between serum adipocytokine levels and microangiopathies in patients with type 2 diabetes mellitus

Aims/Introduction

It is thought that adipocytokines contribute to the increased risk of vascular complications in type 2 diabetes. However, there is still limited information on the relationship between microangiopathies and adipocytokines, such as adiponectin, leptin and tumor necrosis factor‐α (TNF‐α) in patients with type 2 diabetes.

Materials and Methods

The present study examined the relationship between fasting serum adiponectin, leptin, and TNF‐α levels and microangiopathies in Korean type 2 diabetes. A total of 153 patients were recruited and evaluated for diabetic nephropathy, retinopathy and neuropathy. Serum adiponectin, TNF‐α and leptin levels were measured.

Results

Serum adiponectin levels were significantly lower in patients with nephropathy than in those without nephropathy (P = 0.017), and were significantly higher in patients with retinopathy or neuropathy than those without retinopathy or neuropathy (P = 0.01 and P = 0.002, respectively). The mean levels of leptin were significantly higher in patients with neuropathy than in those without neuropathy (P = 0.002). The mean levels of TNF‐α were not significantly different according to any of the three microangiopathies. Multivariate logistic regression analysis showed that the odds ratio for the presence of neuropathy in the highest tertile of adiponectin was 4.3 (95% confidence interval 1.59–11.62), as compared with the patients in the lowest tertile of adiponectin level.

Conclusions

Levels of adipocytokines were significantly different according to the presence of each microangiopathy. In particular, higher serum adiponectin was independently associated with increased odds for the presence of neuropathy. Future prospective studies with larger numbers of patients are required to establish a direct relationship between plasma adipocytokine concentrations and the development or severity of diabetic microangiopathies.     

胃旁路术减肥同时改善糖代谢的机制

胃旁路术在平稳减肥的同时能增加胰岛素敏感性,改善糖代谢紊乱。其机制包括胃减容以减少摄入,前肠旁路致胃肠-胰岛轴改变引起多种胃肠激素如ghrelin、胰升糖素样肽-1（GLP-1）、葡萄糖依赖性促胰岛素多肽、多肽YY等变化改善了胰岛素的分泌和（或）活性,脂肪细胞因子的改变如脂联素水平升高、瘦素及酰化刺激蛋白降低和一些炎性反应因子如C反应蛋白、白细胞介素-6（IL-6）的变化等。     

脂联素及其受体研究进展

脂联素（adiponectin）是来源于脂肪组织的脂肪细胞因子之一，具有抗炎、抗糖尿病、抗动脉粥样硬化和增敏胰岛素的作用。脂联素的这些效应必须通过脂联素受体1（AdipoR1）和AdipoR2的介导。近年的研究发现，AdipoR1在骨骼肌中有丰富表达，AdipoR2主要在肝中表达；AdipoR1和AdipoR2也在人和鼠的胰岛β细胞中表达，其水平与肝中类似，比骨骼肌更高；AdipoR1和AdipoR2也可在单核细胞和巨噬细胞中表达。过氧化物酶体增殖物激活受体-α（PPAR-α）、PPAR-γ和肝X受体（LXR）的激动剂以及生长激素（GH）可影响脂联素受体的表达和调节。     

妊娠糖尿病的研究进展

妊娠糖尿病的患病率和病死率逐年增加,严重影响母婴的健康,但其发病机制至今尚未明确。临床研究发现多种因素促成了妊娠糖尿病的发生,包括胰岛素抵抗、胰岛β细胞功能缺陷、妊娠激素、炎性因子和脂肪细胞因子、遗传等。尤其近年关于炎性因子和脂肪因子的大量研究,为妊娠糖尿病的发病机制及对妊娠糖尿病的筛查和诊断方法的归纳与早期发现妊娠糖尿病提供了有力的依据。     

Polymorphisms in the gene encoding adiponectin receptor 1 are associated with insulin resistance and high liver fat

Aims/hypothesis The adipokine adiponectin has insulin-sensitising, anti-atherogenic and anti-inflammatory properties. Recently, the genes for mouse and human adiponectin receptor-1 (ADIPOR1) and -2 (ADIPOR2) have been cloned. The aim of this study was to investigate whether genetic variants of the genes encoding ADIPOR1 and ADIPOR2 play a role in human metabolism.Materials and methods We screened ADIPOR1 and ADIPOR2 for polymorphisms and determined their association with glucose metabolism, lipid metabolism, an atherogenic lipid profile and inflammatory markers in 502 non-diabetic subjects. A subgroup participated in a longitudinal study; these subjects received diet counselling and increased their physical activity.Results We identified six variants of ADIPOR1 and seven variants of ADIPOR2. A single-nucleotide polymorphism (SNP) in the putative promoter region 8503 bp upstream of the translational start codon (–8503 G/A) of ADIPOR1 (frequency of allele A=0.31) was in almost complete linkage disequilibrium with another SNP (–1927 T/C) in intron 1. Subjects carrying the –8503 A and –1927 C alleles had lower insulin sensitivity, as estimated from a 75 g OGTT (p=0.04) and determined during a euglycaemic clamp (n=295, p=0.04); they also had higher HbA₁c levels (p=0.02) and, although the difference was not statistically significant, higher liver fat (n=85, determined by proton magnetic resonance spectroscopy, p=0.056) (all p values are adjusted for age, sex and percentage of body fat). In the longitudinal study (n=45), the –8503 A and –1927 C alleles were associated with lower insulin sensitivity (p=0.03) and higher liver fat (p=0.02) at follow-up compared with the –8503 G and –1927 T alleles, independently of basal measurements, sex and baseline and follow-up percentage of body fat.Conclusions/interpretation The present findings suggest that the –8503 G/A SNP in the promoter or the –1927 T/C SNP in intron 1 of ADIPOR1 may affect insulin sensitivity and liver fat in humans.Electronic Supplementary Material Supplementary material is available for this article at .