Mecanismo de acción de abatacept: concordancia con su perfil clínico / Abatacept mechanism of action: concordance with its clinical profile

La interacción molecular doble y simultánea entre las células presentadoras de antígeno (CPA) y los linfocitos T es imprescindible para la activación óptima de la respuesta inmunitaria y requiere de la participación de dos grupos de receptores de membrana. El abatacept es una proteína de fusión que modula selectivamente una de estas dos vías, uniéndose a los receptores CD80 y CD86 de las CPA. De esta forma el fármaco inhibe la activación de las células T, bloqueando selectivamente la unión específica de los receptores CD80/CD86 al CD28 y como consecuencia inhibiendo la proliferación de las células T y la respuesta inmunitaria de las células B. Esta acción farmacológica se traduce en la normalización de los niveles de los mediadores inflamatorios en los enfermos con artritis reumatoide y en una respuesta clínica segura y eficaz. El abatacept, en combinación con metotrexato, evita la progresión de la lesión articular y mejora la función física en enfermos con artritis reumatoide (AU)

The double and simultaneous molecular interaction between antigen-presentig cells (APC) and T lymphocytes is essential for the optimal activation of the immunological response and requires the participation of two membrane receptor groups. Abatacept is a fusion protein that selectively modulates one of these two ways, by binding to CD80 and CD86 receptors on APC. In this way, the drug inhibits T cell activation, selectively blocking the specific interaction of CD80/CD86 receptors to CD28 and, therefore, inhibiting T cell proliferation and B cell immunological response. This pharmacological action results in the normalization of inflammatory mediators in rheumatoid arthritis patients and in a safe and efficacious clinical response. Abatacept in combination with methotrexate prevents the progression of joint damage and improves physical function in rheumatoid arthritis patients (AU)

Abatacept mechanism of action: concordance with its clinical profile.

The double and simultaneous molecular interaction between antigen-presentig cells (APC) and T lymphocytes is essential for the optimal activation of the immunological response and requires the participation of two membrane receptor groups. Abatacept is a fusion protein that selectively modulates one of these two ways, by binding to CD80 and CD86 receptors on APC. In this way, the drug inhibits T cell activation, selectively blocking the specific interaction of CD80/CD86 receptors to CD28 and, therefore, inhibiting T cell proliferation and B cell immunological response. This pharmacological action results in the normalization of inflammatory mediators in rheumatoid arthritis patients and in a safe and efficacious clinical response. Abatacept in combination with methotrexate prevents the progression of joint damage and improves physical function in rheumatoid arthritis patients.

Effect of a high dose of glucosamine on systemic and tissue inflammation in an experimental model of atherosclerosis aggravated by chronic arthritis.

Glucosamine sulfate (GS) is a glycosaminoglycan with anti-inflammatory and immunoregulatory properties. Here we set out to explore the effect of GS administration on markers of systemic and local inflammation in rabbits with atherosclerosis aggravated by chronic arthritis. Atherosclerosis was induced in rabbits by maintaining them on a hyperlipidemic diet after producing an endothelial lesion in the femoral arteries. Simultaneously, chronic arthritis was induced in these animals by repeated intra-articular injections of ovalbumin in previously immunized rabbits. A group of these rabbits was treated prophylactically with oral GS (500 mg.kg(-1).day(-1)), and, when the animals were killed, serum was extracted and peripheral blood mononuclear cells (PBMC) were isolated. Furthermore, the femoral arteries, thoracic aorta, and synovial membranes were examined in gene expression studies and histologically. GS administration reduced circulating levels of the C-reactive protein and of interleukin-6. GS also lowered nuclear factor-kappaB activation in PBMC, and it downregulated the expression of both the CCL2 (monocyte chemoattractant protein) and cyclooxygenase-2 genes in these cells. Lesions at the femoral wall were milder after GS treatment, as reflected by the intimal-to-media thickened ratio and the absence of aortic lesions. Indeed, GS also attenuated the histological lesions in synovial tissue. In a combined rabbit model of chronic arthritis and atherosclerosis, orally administered GS reduced the markers of inflammation in peripheral blood, as well as the femoral and synovial membrane lesions. GS also prevented the development of inflammation-associated aortic lesions. These results suggest an atheroprotective effect of GS.

Common haplotypes of the C-reactive protein gene and circulating leptin levels influence the interindividual variability in serum C-reactive protein levels. The Segovia study.

C-reactive protein (CRP) is a marker of systemic inflammation significantly associated with an increased risk of cardiovascular disease in the general population. The aim of our current work was to study those clinical and genetic variables potentially associated with interindividual variability in serum CRP levels. A random sample of 844 participants (450 women, mean age 55 years) from a study carried out on the general Spanish population (The Segovia Study) was studied. Our results showed that age, gender, waist circumference, leptin, impaired glucose tolerance and smoking were the clinical variables significantly associated with variations in serum CRP levels. Among those, leptin showed the strongest association, explaining 11% of the interindividual variability in circulating CRP levels (p<0.001). To study the effect of genetic variants on serum CRP levels, 10 SNPs within the CRP locus were genotyped in 756 participants. Four of these SNPs (rs1417938, rs1800947, rs1130864, rs1205) were significantly associated with CRP levels after adjustment for clinical variables. Among the common haplotypes inferred from eight SNPs, two (CCATGCCT, p=0.025; CTATCCTT, p=0.004) explained 2.9% of the total variation in serum CRP. The results here reported show that 2.9% of the total variation in circulating CRP levels seems to be explained by genetics variations within CRP locus. Furthermore, serum leptin levels are strongly associated with serum CRP levels in our Spanish population.

Sex and body mass index specific regulation of blood pressure by CYP19A1 gene variants.

Sexual dimorphism in blood pressure (BP) regulation has been observed both in humans and experimental animals, and estrogens have been shown to contribute to this epidemiological observation. A key enzyme in determining estrogen levels is aromatase cytochrome P450. The aim of this study was to evaluate the role of the gene encoding aromatase, CYP19A1, as an independent risk factor for hypertension and its relationship with systolic and diastolic BP measures. We genotyped 2 polymorphisms within the CYP19A1 gene, IVS4 rs11575899 and 3'UTR rs10046, in 3448 individuals. In quantitative analysis, we observed significant associations between the 2 polymorphisms and BP values in women, being these associations dependent on BMI and independent of menopause status. The case-control analysis revealed that the most prominent associations were found for nonobese women in diastolic hypertension (DHT): the IVS4_22 and 3'UTR_11 are risk genotypes (OR=1.61, P=0.027 and OR=1.59, P=0.012, respectively), whereas IVS4_11 and 3'UTR_22 genotypes have a protective effect against DHT (OR=0.63, P=0.009, and OR=0.61, P=0.020, respectively). Haplotype analysis confirmed the above associations: among nonobese women the haplotype 21 is overrepresented in hypertensive women (OR=1.33, P=0.004, for DHT and OR=1.25, P=0.026, for systolic hypertension, SHT) and, conversely, the haplotype 12 protects against hypertension (OR=0.78, P=0.015 for DHT and OR=0.82, P=0.04 for SHT). Our study has shown that the CYP19A1 gene may be involved in the genetic regulation of BP in women. This effect is dependent on BMI and independent of menopause status, suggesting that this action is mainly driven by aromatase activity in fat tissue.