Ilaria Sbarsi

Inflammation and Atherosclerosis: The Role of TNF and TNF Receptors Polymorphisms in Coronary Artery Disease

Inflammation plays an important role in the pathogenesis of atherosclerosis and coronary syndromes; moreover, various lines of evidence suggest that genetic factors contribute significantly to the risk of coronary artery disease (CAD). Through its effects on endothelial function, coagulation, insulin resistance and lipid metabolism, the proinflammatory cytokine TNF could be involved in cardiovascular pathophysiology. The aim of our study is to analyze whether TNF gene promoter (-308 G/A; −857 G/A) and TNF receptor polymorphisms (TNFR1 MspA1 I exon 1 and TNFR2 Nla III exon 6) show involvement in CAD predisposition in a group of Italian patients compared with healthy controls. Genotyping was performed by PCR-RFLP. Consecutive Italian patients with angiographically proven CAD (n= 248) were compared with controls (n=241), matched for age, sex and geographical origins. CAD patients showed a higher frequency of the TNF −308 A allele than healthy controls (p=0.046). After stratification according to risk factors for CAD, our analysis revealed that CAD patients with diabetes (p=0.042) and CAD patients without hypertension (p=0.0495) displayed a higher frequency of the TNF −308 AA genotype compared with healthy controls. Our data stress the inflammatory nature of CAD and show a possible involvement of TNF −308G/A promoter polymorphisms in the predisposition to the development of this disease. The less frequent A allele seems to be a predisposing factor for development of CAD in particular pathological settings associated with the disease itself, such as diabetes.

The 374T/A RAGE Polymorphism Protects Against Future Cardiac Events in Nondiabetic Patients with Coronary Artery Disease

BACKGROUND The -374T/A polymorphism of the Receptor for Advanced Glycation End products (RAGE) may exert a protective effect toward the development of atherosclerosis. No data are currently available on the potential prognostic role of this polymorphism in patients with angiographically proven coronary artery disease (CAD). Hereto we sought to address this issue in a large consecutive cohort of patients undergoing coronary revascularization. METHODS A total of 643 CAD patients who underwent myocardial revascularization were followed for 4.2 years (interquartile range: 2.2-8.1 years). The rates of major cardiac adverse events (death, nonfatal myocardial infarction, and unstable angina) were compared according to the -374T/A RAGE polymorphism. RESULTS During a median follow-up period of 4.2 years, the study endpoint was reached by 126/643 patients (19.6%). We observed adverse cardiac events in 13.4% of patients with AA, 17.5% of those with AT, and 24.2% of those with TT genotype (p <0.05). In univariate Cox proportional hazard analysis, the AA genotype was significantly related to a better outcome in nondiabetic patients (hazard ratio: 0.47, 95% CI: 0.20-0.96; p <0.05). No association was found with adverse events in diabetic subjects. After allowance for potential confounders, the AA genotype remained a significant prognostic factor in the nondiabetic group (adjusted HR: 0.41, 95% CI: 0.17-0.94, p <0.05). CONCLUSIONS The -374T/A RAGE polymorphism is an independent protective factor for cardiac events in nondiabetic patients with CAD. The effect of this genetic variant seems to be attenuated in diabetics, who have chronic RAGE upregulation.

Molecular study of receptor for advanced glycation endproduct gene promoter and identification of specific HLA haplotypes possibly involved in chronic fatigue syndrome.

The receptor for advanced glycation end product (RAGE) is thought to play an important role in inflammation. Chronic Fatigue Syndrome (CFS) is a long-lasting fatigue that compromises at least 50% of a subjects daily activities without other known cause. Immune dysfunction has been implicated and an association with a peculiar genetic cytokine profile, predisposing to an immunomodulatory response of inflammatory nature, was found. The aim of this study is to analyse RAGE polymorphisms and HLA-DRB1 alleles in seventy-five Italian CFS patients and 141 controls matched for age, sex and ethnicity. These two groups underwent genomic study for RAGE –374T/A and –429C/T promoter polymorphisms; moreover, 46 patients and 186 controls were typed for HLA-DRB1 at low resolution molecular level. Of these, 31 patients and 99 controls also underwent “high resolution analysis” to define the HLA-DRB1*11 and DRB1*13 alleles. The haplotypes RAGE-374T, DRB1*04; RAGE-374T, DRB1*09; RAGE-374T, DRB1*11; RAGE-374A, DRB1*13; RAGE-429T, DRB1*04 and RAGE-429C, DRB1*11 were significantly more frequent in CFS patients, whereas RAGE-429C, DRB1*07 would seem protective. A significantly lower frequency of DRB1*1104 (5.4% vs 12.9% p=0.04, OR=0.39) and a significantly higher frequency of HLA-DRB1*1301 (13.0% vs 5.1% p=0.006, OR= 2.79) were found in CFS patients. A synergic effect was observed with RAGE polymorphism. The OR values strengthened in the following cis combinations: RAGE-374A, HLA-DRB1*1104 (OR=0.27) and RAGE-374A, HLA-DRB1*1301 (OR=6.23). HLA haplotypes rather than single alleles of RAGE or of DRB1 genes seem to be involved in CFS, probably including a subregion of major interest.

The -374T/A variant of the rage gene promoter is associated with clinical restenosis after coronary stent placement.

Upregulation of the receptor for advanced glycation end products (RAGE) may play a crucial role in neointimal formation upon vessel injury. The −374T/A variant of the RAGE gene promoter, which has been associated with an altered expression of the cell-surface receptor, could exert a protective effect toward the development of vascular disease. The aim of this study is to determine the impact of this common genetic variant in the occurrence of clinical in-stent restenosis after coronary stent implantation. The −374T/A polymorphism of the RAGE gene promoter was evaluated by PCR-RFLPs in 267 patients with coronary artery disease who underwent coronary stent implantation and a subsequent coronary angiography 6–9 months later for suspected restenosis. In-stent restenosis was assessed by means of quantitative angiography. Carriers of the-374AA genotype showed a significantly reduced risk of developing restenosis after percutaneous transluminal intervention than non-carriers. To determine whether the protective effect of the homozygous AA genotype toward clinical restenosis was independent of potential confounders, we performed multivariable logistic regression analysis. After allowance for clinical and biochemical risk factors and stent length, the AA genotype remained significantly associated with a reduced prevalence of in-stent restenosis. No relation was evident between the RAGE genotype and established cardiovascular risk factors. In conclusion, the −374AA genotype of the RAGE gene promoter could be associated with a reduced risk of in-stent restenosis after coronary stent implantation.

HLA haplotypes and birth weight variation: Is your future going to be light or heavy?

Birth weight is known to be a direct indicator of perinatal mortality and a clear predictor of adult pathologies too. It has been correlated with several causes of mortality in adulthood: low birth weight with diabetes, nephropathy and cardiovascular diseases and high birth weight with autoimmune diseases and cancer. In genome-wide studies, an extended human leucocyte antigen (HLA) region has been linked to birth weight variation. We focused our attention on the HLA haplotypes marked by HLA-A, HLA-B and HLA-DRB1 polymorphisms in 1206 healthy Caucasian newborns belonging to the Cord Blood Bank of Pavia (Italy) and their mothers, aiming to investigate the association between this restricted HLA region and birth weight variation. In our study, the HLA-B*38;DRB1*13 haplotype showed an ascending trend among centiles addressing to the high foetal weight. The HLA-A*02;B*15 haplotype showed a descending trend among centiles addressing to the low foetal weight. Besides the acknowledged correlation between the HLA-A*02 and HLA-B*15 alleles (as well as low birth weight) and type I diabetes and between the HLA-B*38 and HLA-DRB1*13 alleles (as well as high birth weight) and several autoimmune diseases, we cannot predict if our babies, healthy at birth, will suffer from these pathologies during life. Nevertheless, our data point to the HLA telomeric end for markers linked to the low birth weight and to the HLA centromeric end for markers linked to the high birth weight, thus limiting the region involved in birth weight variation, which still represents a useful predictor of disease risk in adulthood.

Targeting the Immunogenetic Diseases with the Appropriate HLA Molecular Typing: Critical Appraisal on 2666 Patients Typed in One Single Centre

We compared the immunogenetic data from 2666 patients affected by HLA-related autoimmune diseases with those from 4389 ethnically matched controls (3157 cord blood donors CBD, 1232 adult bone marrow donors BMD), to verify the appropriateness of HLA typing requests received in the past decade. The frequency of HLA-B∗27 phenotype was 10.50% in 724 ankylosing spondylitis, 16.80% in 125 uveitis (3.41% BMD, 4.24% CBD, P < 0.0001); HLA-B∗51 allele was 15.57% in 212 Behçets disease (12.91% BMD, 9.88% CBD, P < 0.0001); the HLA-DRB1-rheumatoid arthritis (RA) shared epitope was 13.72% in 554 RA (10.85% BMD, 13.48% CBD, P = 0.016); the carriers of almost one of HLA-DQB1 susceptibility alleles were 84.91% in 795 celiac disease (CD) and 59.37% in 256 insulin-dependent diabetes mellitus (IDDM) (46.06% in 875 CBD, 42.75% in 662 BMD P < 0.0001). Overall, our results show that the HLA marker frequencies were higher in patients than controls, but lower than expected from the literature data (excluding CD and IDDM) and demonstrate that, in complex immunogenetic conditions, a substantial number of genetic analyses are redundant and inappropriate, burdening to the public health costs. For this reason, we suggest the Italian Scientific Society of Immunogenetics to establish guidelines to improve the appropriateness of typing requests.

On the benefit of blood group molecular genotyping in cord blood banking

Daniels et al. reported on the 3rd International Workshop on Molecular Blood Group Genotyping as a basis for the forthcoming requirement of an inter-Laboratory quality control system for those dealing with erythrogenomics [1]. DNA-based methods for blood group genotyping are spreading worldwide because of their accuracy compared with traditional serologic techniques [2]. Typing for red-blood-cell (RBC) polymorphisms at the DNA level is advantageous in several situations, such as the management of multiply transfused recipients, the prevention of anti-D alloimmunization due to weak RhD variants in blood donors, and the typing of foetuses using amniocytes or cell-free DNA from maternal plasma [3]. We believe molecular blood grouping could also be useful in cord blood (CB) banking. In this setting, serologic blood grouping is usually carried out on fresh CB samples, but is inaccurate after thawing because of haemolysis. The blood group of the newborn itself is not an acceptable substitute. Therefore, if serologic blood grouping has not been carried out on a fresh sample, it is unavailable. And as the CB blood group is a requirement for validation, according to FACT-Netcord international standards [4], CB units lacking it cannot be offered for transplantation, thus wasting human resources. Based on the availability of umbilical cord DNA, we used molecular RBC genotyping in seven out of 3395 units in our CB Bank that were potentially suitable for validation except for lack of blood grouping. ABO and Rh-CDE genotypes were determined by PCR-SSP using the commercial kit READY-GENE ABO and READY-GENE CDE (INNO-TRAIN Diagnostik GmbH, Kronberg ⁄ Taunus, Germany). Genomic DNA was obtained after CB storage times ranging from 1 to 12 years, and from various sources, as shown in Table 1. Molecular genotyping was possible on all the samples, with ABO and Rh polymorphisms as detailed in the table. With minimal increase in initial costs, DNA-based ABO and Rh typing enhanced our CB Bank by validating units otherwise unsuitable, and recovering the cost of their characterization and maintenance. As CB Banks are often in transfusion services, or have their testing done there, we believe this is one more reason to encourage the use of DNA-based methods in transfusion practice. In this setting, the immunogenetics laboratory may reasonably share methods and equipment with an erythrogenomics unit.