Montserrat Broch

New adipokines vaspin and omentin. Circulating levels and gene expression in adipose tissue from morbidly obese women

BackgroundVaspin and omentin are recently described molecules that belong to the adipokine family and seem to be related to metabolic risk factors. The objectives of this study were twofold: to evaluate vaspin and omentin circulating levels and mRNA expression in subcutaneous and visceral adipose tissues in non-diabetic morbidly obese women; and to assess the relationship of vaspin and omentin with anthropometric and metabolic parameters, and other adipo/cytokines.DesignWe analysed vaspin and omentin circulating levels in 71 women of European descent (40 morbidly obese [BMI ≥ 40 kg/m2] and 31 lean [BMI ≤ 25]). We assessed vaspin and omentin gene expression in paired samples of visceral and subcutaneous abdominal adipose tissue from 46 women: 40 morbidly obese and 6 lean. We determined serum vaspin and plasma omentin levels with an Enzyme-Linked Immunosorbent Assay and adipose tissue mRNA expression by real time RT-PCR.ResultsSerum vaspin levels in the morbidly obese were not significantly different from those in controls. They correlated inversely with levels of lipocalin 2 and interleukin 6. Vaspin mRNA expression was significantly higher in the morbidly obese, in both subcutaneous and visceral adipose tissue.Plasma omentin levels were significantly lower in the morbidly obese and they correlated inversely with glucidic metabolism parameters. Omentin circulating levels, then, correlated inversely with the metabolic syndrome (MS). Omentin expression in visceral adipose tissue was significantly lower in morbidly obese women than in controls.ConclusionsThe present study indicates that vaspin may have a compensatory role in the underlying inflammation of obesity. Decreased omentin circulating levels have a close association with MS in morbidly obese women.

Retinol binding protein-4 circulating levels were higher in nonalcoholic fatty liver disease vs. histologically normal liver from morbidly obese women.

We aimed to analyze the retinol binding protein‐4 (RBP4) messenger RNA (mRNA) expression profiles in adipose tissues and liver of morbidly obese (MO) women with or without nonalcoholic fatty liver disease (NAFLD), and to study the relationships with other pro‐ and anti‐inflammatory adipokines in vivo and in vitro.

Influence of chronic alcohol abuse and liver disease on hepatic aldehyde dehydrogenase activity

Alcohol metabolism results in the production of acetaldehyde, a compound that is much more toxic than ethanol itself. Hepatic aldehyde dehydrogenase (ALDH) is the main enzymatic system responsible for acetaldehyde clearance from the hepatocyte. The objective of this study was to determine the modifications in ALDH activity due to chronic alcohol abuse and liver disease. ALDH activity was determined in samples of liver tissue from 69 alcoholic and 82 nonalcoholic subjects, with and without liver disease. According to the results of liver pathology examination, alcoholic patients were classified into the following groups: controls, with no liver disease (group 1), noncirrhotic liver disease patients (group 2), and cirrhotics (group 3). Nonalcoholic subjects were categorized, using the same criteria, into groups 4, 5, and 6, respectively. ALDH activity was determined spectrophotometrically at two substrate concentrations: 18 mM for total activity and 180 microM for low Km activity. High Km activity was calculated by subtracting the low Km activity value from that of total ALDH activity. Results obtained in each group were expressed as the mean +/- SD of mU of g of wet weight. There were no significant differences when the total ALDH activity from the alcoholic and the nonalcoholic patients with a similar degree of liver pathology were compared: group 1, 1257 +/- 587 vs. group 4, 1328.1 +/- 546.2 (p: NS); group 2, 919.1 +/- 452.4 vs. group 5, 753.5 +/- 412 (p: NS); and group 3, 430.2 +/- 162.4 vs. group 6, 473.2 +/- 225.3 (p: NS). On the other hand, total ALDH activity was significantly lower in cirrhotics than in controls, both among alcoholics (p < 0.01) and among nondrinkers (p < 0.05). The low Km activity was severely reduced in cirrhotics, both alcoholics and nonalcoholics (p < 0.01). High Km activities in cirrhotic patients were low, compared to controls, both in alcoholics and nonalcoholics, although the difference was nonsignificant. The results of the present study suggests that chronic alcohol abuse does not depress ALDH activity. A reduction in the ALDH activity detected in patients with severe liver disease (cirrhotics) was clearly a consequence of liver damage. This reduction was due mainly to a decrease of the low Km ALDH activity, but a trend to a decrease in the high Km ALDH activity was also detected.

Spanish HIV-1-infected long-term nonprogressors of more than 15 years have an increased frequency of the CX3CR1 249I variant allele

Background and Objectives:The influence of the polymorphisms of the CX3CR1 chemokine receptor gene on the natural history of HIV-1 infection is controversial. This study aimed to determine whether functionally active CX3CR1 genetic variants are associated with long-term nonprogressive infection of >15 years in HIV-1-infected Spanish patients. Patients and Methods:Two single-nucleotide polymorphisms, V249I (G > A) and T280M (C > T), of the CX3CR1 gene were assessed in 271 Spaniards. These included 60 HIV-1-infected patients who were long-term nonprogressors (LTNPs) of >15 years, 109 HIV-1-infected patients who were usual progressors (UPs), and 102 control subjects. The CCR5Δ32 was also assessed. Genotyping was performed using polymerase chain reaction and automatic sequencing analysis methods on white cell DNA. Genotype and allele frequencies were compared by the χ2 test and the Fisher exact test. Results:The frequencies of the 249I variant allele were 42% for LTNPs, 24.5% for UPs, and 35% for healthy controls; the differences between LTNPs and UPs were significant (odds ratio 0.46; 95% CI: 0.27 to 0.75; P = 0.0017). For 280M the distribution was 16% for LTNPs, 14% for UPs, and 17% for healthy controls (P = NS). The haplotype 249I280T was significantly more common in LTNPs than in UPs (P = 0.0007). These results persisted after excluding from the analysis the individuals carrying the CCR5Δ32. Conclusions:CX3CR1 249I variant allele is more frequent in Spanish HIV-1-infected LTNPs of >15 years. This effect is independent of the presence of the CCR5Δ32 allele.

G Protein β3 Gene Variant, Vascular Function, and Insulin Sensitivity in Type 2 Diabetes

A common polymorphism (825 C/T) in exon 10 of the GNB3 gene, that encodes for the β-3 subunit, has been associated with different degrees of activation of heterotrimeric guanine nucleotide binding proteins (G proteins). Many hormones and neurotransmitters use specific receptors that interact noncovalently with G proteins in the transmembrane signaling process. Among them, insulin uses an inhibitory G protein–sensitive mechanism that is involved in metabolic and vascular events, leading to enhanced glucose transport and vasodilation. We hypothesized differences in peripheral and vascular insulin sensitivity according to GNB3 gene polymorphism in type 2 diabetic patients. To address this issue, we used an intervention-optimization protocol to examine whether diabetic patients with the variant show a different response in terms of insulin-sensitivity. Interindividual differences in baseline insulin sensitivity and vascular dysfunction (vasodilatory response to glyceryl trinitrate) were not attributable to this polymorphism of the GNB3 gene. However, in contrast to normal homozygotes, insulin sensitivity (SI) significantly improved ( P =0.01) in carriers of the 825T variant. Parallel to these findings, stimulated C-peptide tended to decrease, and the response to glyceryl trinitrate significantly improved ( P =0.004) among 825T carriers. Body mass index, systolic and diastolic blood pressure, heart rate, or serum lipid levels did not significantly change in either group. Our findings suggest an effect of GNB3 gene polymorphism on important phenotypic variations in type 2 diabetes mellitus. The GNB3 gene polymorphism might be an example of pharmacogenetics, with the underlying etiological genetic defect altering the response to treatment.

Polymorphism of RANTES chemokine gene promoter is not associated with long-term nonprogressive HIV-1 infection of more than 16 years

To examine whether polymorphisms of the RANTES chemokine gene promoter are associated with long-term nonprogressive HIV-1 infection in white Spanish subjects, we performed a cross-sectional genetic association case-control study. Two-hundred sixty-seven white Spaniards were studied: 58 were HIV-1-infected long-term nonprogressors (LTNPs) of more than 16 years, 109 were HIV-1-infected usual progressors (UPs), and 100 were control subjects. Three RANTES single nucleotide polymorphisms (SNPs) at positions −28C>G, −109T>C, and −403G>A were assessed. The prevalence of the CCR5Δ 32 allele was also examined. Genotyping was performed using polymerase chain reaction and automatic sequencing analysis methods. Genotype and allele frequencies between the 3 groups were compared by the χ2 test and the Fisher exact test. The distribution of allelic variants of RANTES in controls, UPs, and LTNPs, respectively, was 3%, 2%, and 5% for −28G; 4%, 2%, and 2% for −109C; and 18%, 18%, and 18% for −403A (P = not significant). The differences were still nonsignificant when we exclusively analyzed individuals not carrying the CCR5Δ32 allele. We conclude that LTNP of more than 16 years is not associated with SNPs in the RANTES gene promoter in white Spanish HIV-1-infected subjects.

The IL-6 system in HIV-1-infection and in HAART-related fat redistribution syndromes.

We determined the IL-6 −174 G>C single nucleotide polymorphism, IL-6 mRNA expression in subcutaneous adipose tissue (SAT) and IL-6 plasma levels in HIV-1-infected patients with and without lipodystrophy and uninfected controls. HIV-1-infected patients had a greater prevalence of the IL-6 −174 C/C genotype and the C allele, higher SAT IL-6 mRNA expression and plasma IL-6 levels than controls. The IL-6 −174 G>C genotype distribution and allele frequencies, SAT IL-6 mRNA expression and IL-6 plasma levels were non-significantly different between HIV-1-infected patients with and without lipodystrophy.

Lack of association of SDF-1 3'A variant allele with long-term nonprogressive HIV-1 infection is extended beyond 16 years

We studied the frequency of the SDF-1 3′A allelic variant (801G→A) in a cohort of white Spaniards made up of (1) HIV-1-infected long-term nonprogressors (LTNPs) older than 16 years of age (n = 57), (2) HIV-1-infected usual progressors (UPs; n = 107), and (3) a group of healthy controls (n = 100). The mutant SDF-1 3′A allele was observed in 28% of LTNPs, 19% of UPs, and 26% of healthy controls (P = not significant). Homozygosity for the 3′A mutation was detected in 7%, 4%, and 3% of LTNPs, UPs, and healthy controls, respectively (P = not significant). Polymorphism at the SDF-1 locus is not associated with LTNP disease of longer than 16 years in Spanish HIV-1-infected patients. This effect is independent of the CCR5Δ32 allele.

Parallel downregulation of retinol-binding protein-4 and adiponectin expression in subcutaneous adipose tissue of non-morbidly obese subjects

CONTEXT AND OBJECTIVE Adipokines are involved in the etiopathology of obesity-related disorders. Since the role of adipokine retinol-binding protein-4 (RBP4) in obesity remains uncertain and its relationship with other adipokines and inflammatory markers has not been examined in detail, we investigated the relationships of RBP4 mRNA expression and circulating protein levels with obesity, anthropometric and metabolic variables, as well as with obesity-related inflammatory markers adiponectin and C-reactive protein. SUBJECTS AND METHODS One-hundred and twenty-five subjects participated, 36 lean (body mass index (BMI): <25 kg/m(2)) and 89 obese (overweight/obese; BMI: > or =25<40) whose anthropometric and metabolic variables were assessed. mRNA expression was quantified by real-time PCR in subcutaneous adipose tissue (s.c.-AT) of 46 subjects. RESULTS There was a tendency for circulating RBP4 levels to positively correlate with waist circumference (beta=0.29, P=0.08; R(2)=0.08), but there was no significant association with the obesity-related parameters analysed. RBP4 and adiponectin mRNA expression levels were similarly downregulated in the s.c.-AT of obese subjects (0.5-fold); however, RBP4 downregulation did not affect its circulating protein levels. The expression of RBP4 and adiponectin was positively correlated even after controlling for confounding factors (beta=0.59, P<0.0001; R(2)=0.40). CONCLUSIONS In our population, RBP4 circulating levels were not significantly correlated with obesity-related parameters, although a tendency to correlate with waist circumference suggests a relationship with insulin resistance and other metabolic disorders. In addition, our results suggest that the production of RBP4 by other tissues such as liver, rather than s.c.-AT, may be involved in regulating RBP4 circulating levels.

Genetic heterogeneity within ulcerative colitis determined by an interleukin-1 receptor antagonist gene polymorphism and antineutrophil cytoplasmic antibodies.

BACKGROUND Although there is strong evidence implicating genetic predisposition in the pathogenesis of the chronic inflammatory bowel diseases, the number and identity of susceptibility genes remain uncertain. Cytokine genes are tentative candidate loci, but data regarding association studies in different populations are conflicting. AIMS To determine potential associations of interleukin-1 receptor antagonist (IL-1ra), tumour necrosis factor alpha (TNF alpha), and tumour necrosis factor beta (TNF beta) gene polymorphisms with ulcerative colitis or subsets of ulcerative colitis in a Spanish population. METHODS Genotyping for IL-1ra, TNF alpha and TNF beta gene polymorphisms was performed by the polymerase chain reaction in 95 patients with ulcerative colitis and 74 healthy controls. A variable number of tandem repeats (VNTR) in the IL-1ra gene, and a single base pair polymorphism in the TNF alpha gene promoter region (-308) and in the first intron of the TNF beta gene were analysed. Anti-neutrophil cytoplasmic antibodies (ANCA) were detected using an indirect immunofluorescence assay. RESULTS There were no significant differences between ulcerative colitis patients and controls in either polymorphism analysed, nor between ulcerative colitis subgroups as a function of the clinical disease pattern. However, when stratified by their ANCA status, perinuclear ANCA (p-ANCA) ulcerative colitis showed an increased frequency of the genotype 1,2 of the IL-1ra gene compared with ANCA-negative ulcerative colitis (52% versus 28%; P = 0.02, Pcorr = 0.1). Furthermore, p-ANCA ulcerative colitis had a statistically significant increase of this genotype compared with cytoplasmic ANCA (c-ANCA)/ANCA-negative ulcerative colitis (52% versus 26.5%; P = 0.01, Pcorr = 0.05). CONCLUSIONS In the Spanish population studied, the polymorphisms analysed in the IL-1ra, TNF alpha and TNF beta genes are unlikely to be important in the overall susceptibility to ulcerative colitis. However, the combination of a subclinical (p-ANCA) and a genetic (IL-1ra gene) marker identified a distinct ulcerative colitis subgroup (p-ANCA; IL-1ra genotype 1,2). These findings provide further evidence of genetic heterogeneity within ulcerative colitis, and support the concept that ANCA may represent a subclinical marker of genetic heterogeneity.