Nesrine Abboud

Association of factor V gene polymorphisms (Leiden; Cambridge; Hong Kong and HR2 haplotype) with recurrent idiopathic pregnancy loss in Tunisia. A case-control study

Inherited thrombophilia has been shown to be linked with fetal loss. We performed a case-control study on the association between thrombosis-related polymorphisms in the factor V (FV) gene (Leiden, Cambridge, Hong Kong; HR2 haplotype) and idiopathic recurrent pregnancy loss (RPL) in Tunisian women. A total of 348 women with RPL, and 203 control women were studied, corresponding to 1,250 pregnancy losses and 1,200 successful pregnancies. FV Leiden was seen in 19.4% of patients (4.3% in the homozygous state) and in 5.5% of controls. The prevalence of the FV HR2 haplotype was similar in patients and controls, but with 7 homozygous patients for 1 control. FV Cambridge and Hong Kong were absent from both patients and controls. The study of all pregnancy losses evidenced that the frequency of the factor V Leiden polymorphism was zero in women who had mis-carried before 7 weeks of gestation, and then sharply increased to a plateau. After categorization of pregnancy losses (before 8 weeks of gestation; weeks 8 and 9; weeks 10 to 12; from the 13th week of gestation onwards), heterozygous and homozygous factor V Leiden polymorphisms, and homozygous FV HR2 haplotype, were associated with significant and independent risks of pregnancy loss during weeks 8 and 9, which increased during weeks 10 to 12, then culminated after week 12. In Tunisian women with idiopathic RPL, factor V Leiden polymorphism and homozygous FV HR2 haplotype are not a risk factor for very early pregnancy loss, before 8 weeks of gestation, but are thereafter associated with significant clinical risks, which gradually increase from the 8th week onwards.

Association of PAI-1 4G/5G and -844G/A gene polymorphisms and changes in PAI-1/tissue plasminogen activator levels in myocardial infarction: a case-control study.

BACKGROUND Myocardial infarction (MI) is induced by acquired and inherited risk factors, including the plasminogen activator inhibitor-1 (PAI-1) -844G/A and -675G/A (4G/5G) gene variants. OBJECTIVE The aim of this study was to investigate the association between PAI-1-844G/A and 4G/5G polymorphisms and changes in PAI-1 and tissue plasminogen activator (tPA) levels in MI in a Tunisian population. METHODS This was a case-control study involving 305 patients with MI and 328 unrelated healthy controls. PAI-1 genotyping was done by polymerase chain reaction-restriction fragment length polymorphism (RFLP) (-844G/A) or by polymerase chain reaction-allele specific amplification. PAI-1 and tPA levels were assayed by serological assays. RESULTS In contrast to tPA levels, mean plasma PAI-1 antigen levels were higher in cases than in control subjects. The elevation in PAI-1 levels was more pronounced in -844A and 4G allele carriers. Significantly higher frequencies of (mutant) 4G and -844A alleles and 4G/4G and -844A/-844A genotypes, and corresponding lower frequencies of (wild-type) 5G and -844G alleles and 5G/5G and -844G/-844G genotypes were seen in patients than in controls. Increased prevalence of 4G/-844A and decreased prevalence of 5G/-844G haplotypes were seen in patients than in controls, thereby conferring a susceptibility and protective nature to these haplotypes, respectively. Regression analysis confirmed the independent association of 4G/4G and -844A/A with MI, after controlling for a number of covariates. CONCLUSION This study indicated that the risk of MI was notably high in 4G and -844A carriers with elevated plasma PAI-1 and were associated with reduced tPA levels.

―308G>A and ―1031T>C tumor necrosis factor gene polymorphisms in Tunisian patients with coronary artery disease

Abstract Background: Recent research has shown that inflammation plays a key role in coronary artery disease (CAD) and other manifestations of atherosclerosis. Several lines of evidence support a key role for tumor necrosis factor-α (TNF-α), a potent immunomodulator and pro-inflammatory cytokine, in the development of atherosclerosis and in complications of CAD. Methods: We investigated the possible association between CAD and the TNF gene promoter polymorphisms –308G>A and –1031T>C in a Tunisian population. We compared the distribution of these polymorphisms between 418 patients with CAD and 406 healthy controls using polymerase chain reaction restriction fragment length-polymorphism analysis. Results: The frequency of the TNF-α –308A allele in the control group was similar to that observed in CAD patients [p=0.78; odds ratio (OR)=1.15; 95% confidence interval (CI)=0.86–1.55], but higher than those described in other Europeans, such as in the French, Finnish and Spanish. Concerning the TNF-α –1031T/C polymorphism, the same distribution was observed between patients with CAD and controls (p=0.12; OR=1.27; 95% CI=0.94–1.72). In addition, the genotype and allele frequencies of control individuals were comparable to those previously reported in healthy Tunisian controls and other ethnic groups. Haplotype analysis (TNF-α –308G>A and –1031T>C) demonstrated no significant association between TNF haplotypes and CAD. Conclusions: We conclude that TNF promoter gene polymorphisms at position –308G>A and –1031T>C do not play a major role in the pathogenesis of CAD in the Tunisian population. Clin Chem Lab Med 2009;47:1247–51.

TNF-α −308G > A and IL-6 −174G > C polymorphisms in Tunisian patients with coronary artery disease

OBJECTIVE Our aim was to evaluate the contribution of tumor necrosis factor (TNF)-alpha -308G>A and interleukin (IL)-6 -174G>C gene promoter variants to the presence of coronary artery disease (CAD) in Tunisians. DESIGN AND METHODS Study subjects comprised 418 angiographically proven CAD patients and 406 age-, gender-, and ethnic origin-matched controls. Genotyping was performed using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis. RESULTS There were no significant differences in the allelic distribution of TNF-alpha -308A (19.6% vs. 19.0%, P=0.73), and IL-6 -174C (15.6% vs. 14.3%, P=0.47) promoter polymorphisms between CAD patients and control subjects, respectively. In addition, single locus analysis revealed no differences in genotype frequencies between the two study groups, and the combined distribution of both genotypes did not differ significantly between controls and CAD patients (P>0.05). CONCLUSION There is no allelic or genotypic association of TNF-alpha -308G>A and IL-6 -174G>C promoter polymorphisms with CAD in Tunisians, thereby confirming an ethnic-selective contribution of both gene variants to CAD presence.

P-selectin gene polymorphisms and risk of coronary heart disease among Tunisians.

P-selectin plays a key role in inflammation and atherosclerosis, and polymorphic variants of P-selectin were implicated in the pathogenesis of atherosclerotic and inflammatory changes, including coronary heart disease (CHD) in many ethnic groups. We investigated the contribution of P-selectin promoter (−2123C/G, −1969G/A) and exon (Ser290Asn, Asn562Asp, Thr715Pro) polymorphisms to CHD genetic susceptibility among 298 Tunisian CHD patients and 339 controls. Minor allele and genotype frequencies of the five P-selectin SNPs were comparable between patients and controls, except for −2123G/G genotype which was more frequent in cases. The 715Pro allele was present at lower frequency in Tunisians than in Europeans, and was not protective of CHD. Linkage disequilibrium was seen between −1969G/A, and both Ser290Asn and Asn562Asp. Five-loci haplotype analysis did not identify any CHD-protective or CHD-susceptible haplotypes. To our knowledge, this was the first case-control study to be performed on an Arab/North-African population, and demonstrates that none of the five P-selectin polymorphisms investigated influence CHD susceptibility in Tunisian Arabs.

Evaluation of the Contribution of Renin Angiotensin System Polymorphisms to the Risk of Coronary Artery Disease Among Tunisians

Recent studies have identified genetic markers that may directly influence the risk of the coronary artery disease (CAD), in particular the renin angiotensin system genes. Since there are no existing data for the Tunisian population, we investigated the association between these polymorphisms (angiotensin-converting enzyme [ACE] insertion/deletion [Ins/Del]; the angiotensinogen T174M and M235T; and the angiotensin II type 1 receptor A1166C polymorphisms) and CAD in Tunisians. Study subjects comprised 341 cases and 316 age- and sex-matched healthy individuals. Clinical characteristics and other biochemical and environmental risk factors were collected for both. The distribution of the Ins/Del genotypes was significantly different between cases and controls (p = 0.049) with the genotype Ins/Ins identified as a risk, p = 0.02. Similarly, the distributions of the T174M and M235T genotypes were significantly different between cases and controls (p = 0.037 and 0.047, respectively) with 174 M/M and 235 T/T as the risky genotypes (p = 0.001 and 0.026, respectively). However, A1166C genotype frequencies were not significantly different between patients and controls. In conclusion, our results suggest that a significantly higher risk of CAD was associated with the Ins/Del, the M235T, and T174M polymorphisms; other environmental variables such as body mass index; and biochemical variables such as cholesterol.

Polymorphisms of human platelet alloantigens HPA-1 and HPA-2 associated with severe coronary artery disease

OBJECTIVES Insofar as platelet membrane glycoprotein (GP) polymorphisms were identified as potential risk factors for coronary artery disease (CAD), we investigated the contribution of human platelet antigen (HPA)-1 (GPIIb/IIIa) and HPA-2 (GPIb/IX) alleles and haplotypes to CAD pathogenesis. METHODS Study subjects comprised 247 middle-age CAD patients and 316 age-, gender-, and race-matched controls; HPA genotyping was performed by polymerase chain reaction with sequence specific primers. RESULTS The frequencies of HPA-1b (P<.001) and HPA-2b (P<.001) alleles and HPA-1a/1b (P<.001), HPA-1b/1b (P<.001), and HPA-2a/2b (P<.001) genotypes were higher in patients than control subjects. Select HPA haplotypes comprising the HPA-1b/2a (Pc=2.2 × 10(-4)) and HPA-1b/2b (Pc=.001) haplotypes which were positively associated, and the HPA-1a/2a (Pc=3.2 × 10(-5)) which was negatively associated with CAD, confer a disease susceptibility and protective nature to these haplotypes. Multivariate analysis confirmed the positive association of HPA-1b/2a [adjusted odds ratio (aOR)=3.63; 95% CI=2.42-5.43] and HPA-1b/2b (aOR=2.92; 95% CI=1.43-5.94) haplotypes with CAD, after adjustment for a number of covariates. CONCLUSIONS Our results suggest that HPA-1/HPA-2 haplotypes may be considered to be a major risk factor for CAD in middle-aged Tunisians.

Association of three polymorphisms selected from a genome-wide association study with coronary heart disease in the Tunisian population

Despite extensive exploration of many genes, strong evidence of a molecular genetic association with coronary heart disease (CHD) or myocardial infarction (MI) remains to be obtained. Recently, significant interest has emerged in mapping genetic susceptibility for complex traits through whole-genome studies association generating promoting data that will determine the genetic contribution to common human diseases such as coronary heart disease. The aim of the present case-control study including 324 healthy controls and 296 patients with coronary heart disease from Tunisia, was to assess relation between three polymorphisms previously reported to be strongly associated with coronary heart disease in the Welcome Trust Case Control Consortium (WTCCC) and the German myocardial infarction family studies: locus 9p21.3 (rs 1333049), locus 6q25.1 (rs6922269) and 2q36.3 (rs2943634). By single locus analysis, no differences in genotype distribution and allelic frequency were found between the two groups of study. The risk allele (C) for rs2943634 was less frequent among Tunisian population than in controls from the WTCCC and German studies (57% vs 65%). The three SNPs previously reported to be associated with CHD were not replicated in our small sample.

Functional interleukin-10 promoter variants in coronary artery disease patients in Tunisia

OBJECTIVES The contribution of interleukin (IL)-10 promoter variants -1082G/A, -819C/T, and -592C/A to the risk of coronary artery disease (CAD) was investigated in 291 CAD patients and 291 age- and gender-matched control subjects. METHODS AND RESULTS IL-10 genotyping was performed using PCR-allele-specific amplification (PCR-ASA). Regression analysis was employed in assessing the contribution of the IL-10 variants to the overall CAD risk. A higher frequency of the -592A allele (p = 0.004), but not the -1082A (p = 0.828) or -819T (p = 0.952) alleles, was seen in CAD patients. A higher frequency of -592C/A (p = 0.011), and a lower frequency of -592C/C (p = 0.015) genotypes was noted in patients compared to healthy controls. Regression analysis demonstrated an association of -592C/A [OR (95% CI) = 1.82 (1.02-3.23)] and -592A/A [OR (95% CI) = 3.33 (1.27-9.09)] genotypes with 1-artery disease. Haplotype analysis revealed that none of the eight possible IL-10 haplotypes was associated with CAD or with the severity of CAD, and was confirmed by multivariate regression analysis, after adjusting for a number of confounders (smoking, systolic and diastolic blood pressure, hypertension, diabetes, glucose, cholesterol, and triglycerides). CONCLUSIONS Our results suggest that the -592C/A, more so than the -1082G/A or the -819C/T IL-10 promoter variant alleles, may be considered to be a risk factor for CAD in Tunisians.

Interleukin-10 microsatellite variants and the risk of acute coronary syndrome among Tunisians

The objective of the study was to investigate the association of interleukin (IL)‐10 promoter microsatellite polymorphisms, linked with altered IL‐10 secretion, with the susceptibility to acute coronary syndrome (ACS) in adult Tunisian patients. We genotyped 291 ACS patients and 291 age‐, gender‐ and ethnically matched control subjects for the microsatellites IL‐10R [X78437.2g.5325CA(11_15)] and IL‐10G [X78437.2g.8134CA(14_29)] by PCR‐based assays. Haplotypes were reconstructed using maximum likelihood method. Regression analysis was used in determining the risk imparted by specific IL‐10 genotypes and haplotypes. A significant decrease in IL‐10G12 (24 CA repeats) (P < 0.001; OR = 0.465) and IL‐10G15 (27 CA repeats) (P = 0.043; OR = 0.232), and a significant increase in the low IL‐10 producer allele, IL‐10R3 (14 CA repeats) (P = 0.049; OR = 1.461), microsatellites were seen in the ACS group compared with controls. Of the possible 14 haplotypes constructed, there was an enrichment of the R2G9 (13CA vs. 21CA) haplotype in controls [P = 0.019; adjusted OR (95% CI) = 0.67 (0.48–0.94)] and R2G15 (13CA vs. 27CA) haplotype in cases [P = 0.042; adjusted OR (95% CI) = 5.29 (1.06–26.30)], thus assigning a protective and susceptible nature to these haplotypes respectively. The differential association of IL‐10 microsatellite alleles and haplotypes with ACS suggests that IL‐10 contributes to ACS pathogenesis. While the functional attributes of these microsatellite markers remain to be seen, it is likely that they have distinct functional properties (altered IL‐10 secretion), which in turn affect the susceptibility to ACS development.