Contribució de les citocines proinflamatòries, factor de necrosi tumoral alfa (tnea) i interleucina 6 (il-6), a la resistència a la insulina. Estudi serològic i genètic

La Diabetes mellitus tipo 2 (DM2) está causada principalmente por la disminución de la acción de la insulina (resistencia a la insulina) y por el deterioramiento de la función de las células beta. La DM2 y la obesidad se hallan íntimamente relacionadas. Así, el tejido adiposo es capaz de sintetizar y secretar diversas moléculas que se han visto implicadas en la modulación de la sensibilidad a la insulina (Si). Entre estas moléculas están las citocinas Factor de Necrosis Tumoral alfa (TNF) y la Interleucina 6 (IL-6).El TNF actúa mediante los receptores TNFR1 y TNFR2. La unión de la citocina a sus receptores forma las fracciones solubles de los receptores (sTNFR1 y sTNFR2)."In vivo", la inyección de esta citocina puede inhibir el transporte de glucosa al interior de la célula mediada por insulina. En animales obesos y/o diabéticos inducidos genéticamente existe una sobreexpresión de la citocina en el tejido adiposo y niveles circulantes de la proteína más elevados.En obesidad humana existe una sobrexpresión de TNF y de TNFR2 en tejido adiposo y niveles de las sTNFR2 circulantes aumentados. Estas sobreexpresiones se relacionan positivamente con el índice de masa corporal y los niveles de insulina, ambos marcadores de resistencia a la insulina.En cuanto a la IL-6, su infusión induce a hipertrigliceridemia "in vivo" y "in vitro". En humanos, la citocina se encuentra sobreexpresada en la obesidad y en la DM2, relacionándose con los marcadores clásicos de resistencia a la insulina. El alelo G del polimorfismo -174G>Cde la IL-6 se asocia a tasas de transcripción elevadas.Los trabajos que presentamos tienen como objetivo estudiar el sistema TNF y la IL-6 y su relación con la sensibilidad a la insulina.1. Plasma levels of the soluble fraction of tumor necrosis factor receptor 2and insulin resistance. Diabetes, 47:1757-62, 1998Los niveles de sTNFR2 son más elevados en población obesa (BMI >30 2. Polymorphism of the tumor necrosis factor receptor 2 gene is associated with obesity, leptin levels, and insulin resistance in young subjects and diettreated type 2 diabetic patients. Diabetes Care, 23:831-837, 2000En una población con DM2 y una control analizamos la región 3'UTR del gen del TNFR2 y hallamos 4 variantes que identificamos por secuenciación. La variante A2 se asocia a niveles elevados de BMI y de leptina, sobre todo en la población joven (edad 3. Interleukin-6 gene polymorphism and insulin sensitivity. Diabetes, 49:517-520, 2000Se analiza el polimorfismo -174G>C del gen de la IL-6 en población obesa (BMI4. Interleukin-6 gene polymorphism and lipid abnormalities in healthy subjects. J Clin Endocrinol Metab 85:1334-1339, 2000La misma población que el estudio anterior se caracteriza deun perfil lipídico y se determinan los niveles de la IL-6. Los individuos portadores del alelo G presentan niveles más altos de triglicéridos y de ácidos grasos libres antes y después del test OGTT. Los niveles de IL-6 correlacionaron positivamente con estos parámetros lipídicos.Conclusiones:1- La determinación de los niveles de sTNFR2 podría presentarse como marcador de resistencia a la insulina2- La región 3'UTR del gen del TNFR2 podría ser marcador genético asociado al síndrome metabólico.3- El polimorfismo de restricción -174G>C del gen de la IL-6 podría participar en la predisposición genética del grado de resistencia a la insulina y de los niveles lipídicos.Type 2 diabetes mellitus (DM2) was caused basically by the reduction of the insulin action (insulin resistance) and by the deterioration of the beta cells function. The DM2 and obesity are intimately related between them. In this way, the adipose tissue is able to synthesize and secrete various molecules that are related to the insulin sensitivity (Si) modulation such as Tumor Necrosis Factor-alfa (TNF) and interleukin-6 (IL-6).TNF- signals thorough at least two known cell-surface receptors: TNFR1 and TNFR2. The joining of the cytokine to their receptors derived to receptors soluble forms (sTNFR1 and sTNFR2). "In vivo" studies, cytokine supply could inhibit the insulin-stimulated glucose uptake. In genetic fat and /or diabetics animals there is an over-expression of this cytokine in fat tissue and in plasma.In obese patients, there is an over-expression of TNF and TNFR2 in fat tissue and of sTNFR2 in plasma. These over-expressions are related to the body mass index and insulin levels, both markers of insulin resistance.On the other hand, the IL-6 induces to hypertrygliceridemia "in vivo" and "in vitro".In humans, this cytokine is over-expressed in obese and DM2 patients and it is involved in the classical insulin resistance markers. G-allele of the -174G>C polymorphism has been found to be associated with elevated transcription rates.The goals of the presented studies are to analyse TNF system and IL-6 and their relation to insulin sensitivity.1. Plasma levels of the soluble fraction of tumor necrosis factor receptor 2 and insulin resistance. Diabetes, 47:1757-62, 1998Obese patients (BMI >30 2. Polymorphism of the tumor necrosis factor receptor 2 gene is associated with obesity, leptin levels, and insulin resistance in young subjects and diettreated type 2 diabetic patients. Diabetes Care, 23:831-837, 2000 3´ Untranslated region of the TNFR2 gene was analysed in DM2 and control populations. It was found four alleles identified by sequencing analysis. A2 allele exhibited significantly higher BMI and leptin levels in young population (younger than 54 years-old). In a subgroup of control subjects it was found that people with A2 allele showed several characteristics of the insulin resistance syndrome such as increased waist-to-hit ratio and hypertrygliceridemia in association with a lower insulin sensitivity index.3. Interleukin-6 gene polymorphism and insulin sensitivity. Diabetes, 49:517- 520, 2000It was analysed the -174G>C polymorphism IL-6 gene in obese patients (BMI4. Interleukin-6 gene polymorphism and lipid abnormalities in healthy subjects. J Clin Endocrinol Metab 85:1334-1339, 2000The same population than in the previous study was characterised through a lipidic profile and IL-6 levels were measured. Subjects carrying the G allele showed higher plasma levels of triglycerides and free fatty acids before and post OGTT test. Plasma IL-6 levels were significantly associated with these lipidic parameters.Conclusions1.- The measure of plasma sTNFR2 levels may be used as an insulin sensitivity marker2.- 3´untranslated region of TNFR2 gene may be used as a genetic marker associated with metabolic syndrome3.- -174G>C restriction polymorphism of IL-6 gene may be related with genetic predisposition to insulin sensitivity rate and to plasma lipids levels

Effect of TNF-a genetic variants and CCR5 Delta 32 on the vulnerability to HIV-1 infection and disease progression in Caucasian Spaniards

Background: Tumor necrosis factor alpha (TNF-α) is thought to be involved in the various immunogenetic events that influence HIV-1 infection. Methods: We aimed to determine whether carriage of the TNF-α-238G>A, -308G>A and -863 C>A gene promoter single nucleotide polymorphisms (SNP) and the CCR5Δ32 variant allele influence the risk of HIV-1 infection and disease progression in Caucasian Spaniards. The study group consisted of 423 individuals. Of these, 239 were uninfected (36 heavily exposed but uninfected [EU] and 203 healthy controls [HC]) and 184 were HIV-1-infected (109 typical progressors [TP] and 75 long-term nonprogressors [LTNP] of over 16 years' duration). TNF-α SNP and the CCR5Δ32 allele were assessed using PCR-RFLP and automatic sequencing analysis methods on white blood cell DNA. Genotype and allele frequencies were compared using the χ 2 test and the Fisher exact test. Haplotypes were compared by logistic regression analysis. Results: The distribution of TNF-α-238G>A, -308G>A and -863 C>A genetic variants was non-significantly different in HIV-1-infected patients compared with uninfected individuals: -238G>A, p = 0.7 and p = 0.3; -308G>A, p = 0.05 and p = 0.07; -863 C>A, p = 0.7 and p = 0.4, for genotype and allele comparisons, respectively. Haplotype analyses, however, indicated that carriers of the haplotype H3 were significantly more common among uninfected subjects (p = 0.04). Among the infected patients, the distribution of the three TNF-α genetic variants assessed was non-significantly different between TP and LTNP: -238G>A, p = 0.35 and p = 0.7; -308G>A, p = 0.7 and p = 0.6: -863 C>A, p = 0.2 and p = 0.2, for genotype and allele comparisons, respectively. Haplotype analyses also indicated non-significant associations. Subanalyses in the LTNP subset indicated that the TNF-α-238A variant allele was significantly overrepresented in patients who spontaneously controlled plasma viremia compared with those who had a detectable plasma viral load (genotype comparisons, p = 0.02; allele comparisons, p = 0.03). The CCR5Δ32 distribution was non-significantly different in HIV-1-infected patients with respect to the uninfected population (p = 0.15 and p = 0.2 for genotype and allele comparisons, respectively) and in LTNP vs TP (p = 0.4 and p = 0.5 for genotype and allele comparisons, respectively). Conclusions: In our cohort of Caucasian Spaniards, TNF-α genetic variants could be involved in the vulnerability to HIV1 infection. TNF-α genetic variants were unrelated to disease progression in infected subjects. The -238G>A SNP may modulate the control of viremia in LTNP. Carriage of the CCR5Δ32 variant allele had no effect on the risk of infection and disease progression

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. We performed a cross-sectional analysis of subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT) and liver samples from four lean and 45 MO women with or without NAFLD by enzyme-linked immunosorbent assay and real-time reverse transcription-PCR. We also studied RBP4 expression in HepG2 hepatocytes under various inflammatory stimuli. Circulating RBP4 levels were higher in MO women, and specifically, in MO subjects with NAFLD compared with normal liver controls (lean and MO). RBP4 liver expression was higher in nonalcoholic steatohepatitis (NASH)-moderate/severe than in NASHmild. Overall RBP4 gene expression was higher in liver than in adipose tissues. Among them, the higher expression corresponded to SAT. VAT expression was lower in the MO cohort. In HepG2, RBP4 mRNA expression was reduced by tumor necrosis factor (TNF)-α and increased by adiponectin treatment. In conclusion, the results obtained in MO women with NAFLD, brings up the use of RBP4 and other adipokines as a panel of noninvasive molecular biomarkers when NAFLD is suspected. Further studies are needed with other obesity groups.Fil: Terra, Ximena. Universitat Rovira i Virgil. Departament de Medicina i Cirurgia; EspañaFil: Auguet, Teresa. Universitat Rovira i Virgil. Departament de Medicina i Cirurgia; España. Hospital Universitari Joan XXIII. Servei Medicina Interna,; EspañaFil: Broch, Montserrat. Universitat Rovira i Virgil. Departament de Medicina i Cirurgia; EspañaFil: Sabench, Fátima. Hospital Sant Joan de Reus. Servei de Cirurgia,; EspañaFil: Hernandez, Mercè. Hospital Sant Joan de Reus. Servei de Cirurgia,; EspañaFil: Pastor, Rosa M.. Hospital Universitari Joan XXIII. Laboratori de Bioquímica; EspañaFil: Quesada, Isabel María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Universitat Rovira i Virgil. Departament de Medicina i Cirurgia; EspañaFil: Lunna, Ana. Universitat Rovira i Virgil. Departament de Medicina i Cirurgia; EspañaFil: Aguilar, Carmen. Universitat Rovira i Virgil. Departament de Medicina i Cirurgia; EspañaFil: Del Castillo, Daniel. Hospital Sant Joan de Reus. Servei de Cirurgia, ; EspañaFil: Richard, Cristobal. Universitat Rovira i Virgil. Departament de Medicina i Cirurgia; España. Hospital Universitari Joan XXIII. Servei Medicina Interna,; Españ

Tumor necrosis factor system activity is associated with insulin resistance and dyslipidemia in myotonic dystrophy

Myotonic dystrophy (MyD) is a multisystem autosomal dominant disorder associated with progressive muscle wasting and weakness. The striking metabolic abnormality in MyD is insulin resistance. The mechanism by which target tissues are insensitive to insulin action remains uncertain. In a recent study, plasma soluble tumor necrosis factor receptor (sTNFR)2 levels were found to be associated with muscle tissue mass and insulin resistance. Given these associations, we speculated that disorders of the muscle cell membrane could lead simultaneously to insulin insensitivity and sTNFR2 leakage in MyD. To test this hypothesis, we measured the levels of circulating sTNFR1 and sTNFR2 and insulin resistance in MyD patients. We studied 22 MyD patients and 24 age-, BMI-, and fat mass-matched control subjects. Both MyD men and women showed higher plasma insulin levels in the presence of comparable glucose concentrations than did control subjects. sTNFR2, but not sTNFR1, levels were approximately 1.5-fold higher in MyD patients. In parallel with these findings, the fasting insulin resistance index (FIRI) was also higher in MyD patients. In fact, in the whole population, fasting insulin and FIRI strongly correlated with sTNFR2 in both men (r = 0.77 and r = 0.81, P<0.0001, respectively) and women (r = 0.67 and r = 0.64, P = 0.001, respectively). sTNFR2 levels were also associated with the insulin sensitivity index (S(I)), calculated from an oral glucose tolerance test (OGTT) according to the method by Cederholm and Wibell (r = -0.43, P = 0.006). We constructed a multiple linear regression to predict FIRI, with BMI, waist-to-hip ratio, and sTNFR2 as independent variables. In this model, both BMI (P = 0.0014) and sTNFR2 (P = 0.0048) levels contributed independently to 46% of the variance of FIRI. In another model, in which FIRI was substituted for S(I) from the OGTT, both BMI (P = 0.0001) and sTNFR2 (P = 0.04) levels contributed independently to 48% of the variance of S(I) from the OGTT. Plasma cholesterol and triglyceride concentrations were significantly increased in MyD patients. sTNFR1 and sTNFR2 levels were found to be strongly associated with plasma cholesterol, LDL cholesterol, and triglycerides. sTNFR1 and sTNFR2 also correlated with serum creatine kinase activity in MyD patients (r = 0.57, P = 0.006; r = 0.75, P<0.0001, respectively). In conclusion, here we describe, for the first time to our knowledge, a relationship between insulin action and plasma sTNFR2 concentration in MyD patients. We have also found increased concentrations of plasma triglycerides and cholesterol levels in parallel with sTNFR1 and sTNFR2 concentrations in MyD patients. We speculate that the latter associations are dependent on, and secondary to, increased tumor necrosis factor (TNF)-alpha action. Whether TNF action is implicated in the pathogenesis of MyD or is a simple marker of disease activity awaits further studies

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

<p>Abstract</p> <p>Background</p> <p>Vaspin 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.</p> <p>Design</p> <p>We 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.</p> <p>Results</p> <p>Serum 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.</p> <p>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.</p> <p>Conclusions</p> <p>The 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.</p

Effect of TNF-α genetic variants and CCR5Δ32 on the vulnerability to HIV-1 infection and disease progression in Caucasian Spaniards

<p>Abstract</p> <p>Background</p> <p>Tumor necrosis factor alpha (TNF-α) is thought to be involved in the various immunogenetic events that influence HIV-1 infection.</p> <p>Methods</p> <p>We aimed to determine whether carriage of the <it>TNF-α-238G>A, -308G>A </it>and <it>-863 C>A </it>gene promoter single nucleotide polymorphisms (SNP) and the <it>CCR5Δ32 </it>variant allele influence the risk of HIV-1 infection and disease progression in Caucasian Spaniards. The study group consisted of 423 individuals. Of these, 239 were uninfected (36 heavily exposed but uninfected [EU] and 203 healthy controls [HC]) and 184 were HIV-1-infected (109 typical progressors [TP] and 75 long-term nonprogressors [LTNP] of over 16 years' duration). <it>TNF-α </it>SNP and the <it>CCR5Δ32 </it>allele were assessed using PCR-RFLP and automatic sequencing analysis methods on white blood cell DNA. Genotype and allele frequencies were compared using the χ 2 test and the Fisher exact test. Haplotypes were compared by logistic regression analysis.</p> <p>Results</p> <p>The distribution of <it>TNF-α-238G>A, -308G>A </it>and <it>-863 C>A </it>genetic variants was non-significantly different in HIV-1-infected patients compared with uninfected individuals: <it>-238G>A</it>, p = 0.7 and p = 0.3; <it>-308G>A</it>, p = 0.05 and p = 0.07; <it>-863 C>A</it>, p = 0.7 and p = 0.4, for genotype and allele comparisons, respectively. Haplotype analyses, however, indicated that carriers of the haplotype H3 were significantly more common among uninfected subjects (p = 0.04). Among the infected patients, the distribution of the three <it>TNF-α </it>genetic variants assessed was non-significantly different between TP and LTNP: <it>-238G>A</it>, p = 0.35 and p = 0.7; <it>-308G>A</it>, p = 0.7 and p = 0.6: <it>-863 C>A</it>, p = 0.2 and p = 0.2, for genotype and allele comparisons, respectively. Haplotype analyses also indicated non-significant associations. Subanalyses in the LTNP subset indicated that the <it>TNF-α-238A </it>variant allele was significantly overrepresented in patients who spontaneously controlled plasma viremia compared with those who had a detectable plasma viral load (genotype comparisons, p = 0.02; allele comparisons, p = 0.03). The <it>CCR5Δ32 </it>distribution was non-significantly different in HIV-1-infected patients with respect to the uninfected population (p = 0.15 and p = 0.2 for genotype and allele comparisons, respectively) and in LTNP vs TP (p = 0.4 and p = 0.5 for genotype and allele comparisons, respectively).</p> <p>Conclusions</p> <p>In our cohort of Caucasian Spaniards, <it>TNF-α </it>genetic variants could be involved in the vulnerability to HIV-1 infection. <it>TNF-α </it>genetic variants were unrelated to disease progression in infected subjects. The <it>-238G>A </it>SNP may modulate the control of viremia in LTNP. Carriage of the <it>CCR5Δ32 </it>variant allele had no effect on the risk of infection and disease progression.</p

Tumor necrosis factor system activity is associated with insulin resistance and dyslipidemia in myotonic dystrophy

Myotonic dystrophy (MyD) is a multisystem autosomal dominant disorder associated with progressive muscle wasting and weakness. The striking metabolic abnormality in MyD is insulin resistance. The mechanism by which target tissues are insensitive to insulin action remains uncertain. In a recent study, plasma soluble tumor necrosis factor receptor (sTNFR)2 levels were found to be associated with muscle tissue mass and insulin resistance. Given these associations, we speculated that disorders of the muscle cell membrane could lead simultaneously to insulin insensitivity and sTNFR2 leakage in MyD. To test this hypothesis, we measured the levels of circulating sTNFR1 and sTNFR2 and insulin resistance in MyD patients. We studied 22 MyD patients and 24 age-, BMI-, and fat mass-matched control subjects. Both MyD men and women showed higher plasma insulin levels in the presence of comparable glucose concentrations than did control subjects. sTNFR2, but not sTNFR1, levels were approximately 1.5-fold higher in MyD patients. In parallel with these findings, the fasting insulin resistance index (FIRI) was also higher in MyD patients. In fact, in the whole population, fasting insulin and FIRI strongly correlated with sTNFR2 in both men (r = 0.77 and r = 0.81, P<0.0001, respectively) and women (r = 0.67 and r = 0.64, P = 0.001, respectively). sTNFR2 levels were also associated with the insulin sensitivity index (S(I)), calculated from an oral glucose tolerance test (OGTT) according to the method by Cederholm and Wibell (r = -0.43, P = 0.006). We constructed a multiple linear regression to predict FIRI, with BMI, waist-to-hip ratio, and sTNFR2 as independent variables. In this model, both BMI (P = 0.0014) and sTNFR2 (P = 0.0048) levels contributed independently to 46% of the variance of FIRI. In another model, in which FIRI was substituted for S(I) from the OGTT, both BMI (P = 0.0001) and sTNFR2 (P = 0.04) levels contributed independently to 48% of the variance of S(I) from the OGTT. Plasma cholesterol and triglyceride concentrations were significantly increased in MyD patients. sTNFR1 and sTNFR2 levels were found to be strongly associated with plasma cholesterol, LDL cholesterol, and triglycerides. sTNFR1 and sTNFR2 also correlated with serum creatine kinase activity in MyD patients (r = 0.57, P = 0.006; r = 0.75, P<0.0001, respectively). In conclusion, here we describe, for the first time to our knowledge, a relationship between insulin action and plasma sTNFR2 concentration in MyD patients. We have also found increased concentrations of plasma triglycerides and cholesterol levels in parallel with sTNFR1 and sTNFR2 concentrations in MyD patients. We speculate that the latter associations are dependent on, and secondary to, increased tumor necrosis factor (TNF)-alpha action. Whether TNF action is implicated in the pathogenesis of MyD or is a simple marker of disease activity awaits further studies