Sarra Saidi

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.

Polymorphisms of the human platelet alloantigens HPA-1, HPA-2, HPA-3, and HPA-4 in ischemic stroke

Polymorphism in human platelet antigen (HPA)‐1 and HPA‐3 (GPIIb/IIIa), HPA‐2 (GPIb/IX), HPA‐4 (GPIIIa), and HPA‐5 (GPIa/IIa) was investigated in 329 stroke patients and 444 matched control subjects. HPA genotyping was done by PCR‐SSP method. Lower HPA‐1a (P < 0.001) and higher HPA‐1b (P < 0.001) allele frequencies were seen in patients than control subjects, and homozygosity for HPA‐1b (P < 0.001) alleles was more prevalent in stroke cases than in controls. The allele and genotype distributions of the other HPA polymorphic variants were similar between cases and controls. Select HPA combined genotypes comprising the 2121 (Pc = 0.008) and 2221 (Pc = 0.018) genotypes, which were positively associated, and the 1111 (Pc < 0.001), which was negatively associated with stroke, thereby conferred a disease susceptibility and protective nature to these genotype combinations. Multivariate analysis confirmed the negative association of the 1111 (P < 0.001) and the positive association of the 2121 (P = 0.017) combined genotypes with stroke, after adjustment for a number of covariates. This is the first evidence demonstrating differential association of the common 4 HPA gene variants and specific HPA genotype combinations with stroke. Am. J. Hematol. 2008.

Lupus anticoagulants and anti‐phospholipid antibodies as risk factors for a first episode of ischemic stroke

Summary.  Background: Antiphospholipid antibodies (aPLA) and lupus anticoagulant (LAC) were shown to precipitate thromboembolic events. Their association with ischemic stroke remains to be seen. Objectives: We investigated the contribution of LAC, and antibodies directed against the phospholipids cardiolipin (aCL), phosphatidylserine (aPS), and the phospholipid‐dependent cofactors β2‐glycoprotein I and annexin V, to the risk for ischemic stroke. Patients/methods: LAC and antibody levels were measured in 208 stroke patients and 203 age‐ and gender‐matched control subjects. Results: Positive LAC resulted in an increased risk for stroke [OR (95% CI) = 8.1 (2.4–27.5)]. Significant elevation in aPS IgG, aCL IgM and aCL IgG titers, and increased prevalence of elevated aPS IgG, aCL IgM and aCL IgG (based on P95 cutoff values of healthy individuals) were seen in patients. aPS IgG was associated with cardioembolic, whereas aCL IgG and IgM were elevated in lacunar, atherosclerotic and cardioembolic, and LAC positivity was documented only in lacunar stroke subtypes. The co‐presence of LAC with a positive aCL IgM/IgG or aPS IgG did not affect the overall risk for stroke. Multivariate analysis confirmed the association of positive LAC with stroke [aOR (95% CI) = 9.7 (1.8–52.5)], and demonstrated a clear gradation of increasing risk of stroke associated with the four categories of aCL IgG and aPS IgG, and identified aCL IgM P95 as independent predictors of stroke after adjusting for potentially confounding covariates. Conclusions: Our study demonstrates that the presence of LAC, and elevated aCL IgG and aPS IgG antibodies are risk factors for stroke.

Endothelial nitric oxide synthase Glu298Asp, 4b/a, and -786T>C gene polymorphisms and the risk of ischemic stroke.

Saidi S, Mallat SG, Almawi WY, Mahjoub T. Endothelial nitric oxide synthase Glu298Asp, 4b/a, and −786T>C gene polymorphisms and the risk of ischemic stroke
Acta Neurol Scand: 2010: 121: 114–119.
© 2009 The Authors Journal compilation

Association between renin-angiotensin-aldosterone system genotypes and haplotypes and risk of ischemic stroke of atherosclerotic etiology

Objective –  The association of renin C‐4063T and angiotensinogen (AGT) T174M, AGT M235T and AGT A‐6G polymorphisms with ischemic stroke of atherosclerotic etiology was investigated in 329 Tunisian patients with stroke and 444 controls.

Association of Human Platelet Alloantigen 1 through 5 Polymorphisms with Ischemic Stroke

Polymorphisms in human platelet alloantigen (HPA)-1 and HPA-3 (GPIIb/IIIa), HPA-2 (GPIb/IX), HPA-4 (GPIIIa) and HPA-5 (GPIa/IIa) were investigated in 216 stroke patients and 318 matched control subjects. HPA genotyping was done by the polymerase chain reaction method using sequence-specific primers. Higher frequencies of the HPA-1 a/b (p < 0.001) and HPA-5 a/b (p < 0.001) allele, together with HPA-1 b/b, HPA-5 a/b and HPA-5 b/b genotypes were seen in patients, which was confirmed by regression analysis after controlling for a number of confounding variables. Furthermore, HPA-1 b/b and HPA-5 b/b were significantly associated with the extent of neurological symptoms, and with the recurrence of stroke. Both susceptible (1a/b-2a/a-3a/b-4a/a-5a/b) and protective (1a/a-2a/a-3a/a-4a/a-5a/a; 1a/a-2a/a-3a/b-4a/a-5a/a; 1a/b-2a/a-3a/a-4a/a-5a/a; 1a/b-2a/a-3a/b-4a/a-5a/a) HPA genotypes were identified. This is the first evidence demonstrating differential association of the common 5 HPA gene variants with stroke, with HPA-1b and HPA-5b representing strong genetic risk factors.

Aldosterone synthase gene (CYP11B2) promoter polymorphism as a risk factor for ischaemic stroke in Tunisian Arabs

Introduction. We investigated the contribution of aldosterone synthase CYP11B2 polymorphism (C—344T) to the age-related changes in blood pressure in stroke patients. Subjects and methods. Study subjects comprised 329 stroke patients (121 normotensive, 208 hypertensive) and 444 healthy controls. Genotyping was done by PCR-RFLP, and the contribution of CYP11B2 polymorphism to the risk of stroke was analysed by regression analysis. Results. The T allele, and CT, TT, and CT + TT genotypes, independently of sex and age, were significantly associated with increased stroke risk. Varied distributions of CYP11B2 genotypes were noted among patients with respect to gender, age and hypertension status, being pronounced in hypertensive patients. Both systolic and diastolic blood pressure were positively correlated with the presence of T allele. Mean systolic and diastolic blood pressure were significantly higher among young (< 60 years) CT and TT genotype carriers. Regression analysis confirmed the positive association of CT and TT genotypes and systolic blood pressure, and the negative association of diastolic blood pressure with odds of stroke development. Taking normotensive patients as reference, regression analysis identified TT genotype, age and female gender to be independently associated with increased odds of stroke. Conclusion. Compared to CC genotype, CT and TT CYP11B2 genotypes are independently associated with increased stroke index.

M - 2 Évaluation du polymorphisme génétique de l’inhibiteur de type 1 des activateurs du plasminogène (PAI-1) dans les accidents ischémiques cérébraux

Introduction Les anomalies de systeme fibrinolytique en particulier une concentration elevee du PAI-1, principal inhibiteur de la fibrinolyse, sont associees a un risque plus eleve de survenue d’Accidents ischemiques cerebraux (AIC). Objectifs Determiner l’association entre les polymorphismes de PAI-1 (4 g/5G et - 844 G/A) et le taux antigenique de PAI-1 et de t-PA chez les patients presentant un AIC. Methodes Etude cas — temoins de 135 patients victimes d’AIC et de 118 temoins sans aucun risque thromboembolique. Le genotypage est effectue selon la methode PCR-ASA pour le polymorphisme (4 g/5G) de PAI-1 et par PCR-RFLP (Xho 1) pour celui de (- 844 G/A). Le dosage des taux plasmatiques de PAI-1 et de t-PA est mesure par la methode ELISA. Resultats Un effet protecteur du genotype 4 g/4 g par rapport aux autres genotypes homozygotes mutes (OR = 0,54 ; 95 p. 100 CI = 0,31-0,95) fut retrouve. L’haplotype 4 g/-844A a ete fortement associe a une reduction de risque de l’AVC (OR = 0,43 ; 95 p. 100 CI = 0,20-0,97) par rapport a celui du 5G/-844A (OR = 1,64 ; 95 p. 100 CI = 1,01-2,64) et 4 g/-844G. Association statistiquement significative de l’activite antigenique du PAI-1 et les homozygotes mutes 4 g/4 g. Discussion Nos resultats montrent un role protecteur de l’allele 4 g dans les AIC. Le mecanisme implique dans la survenue des AIC, outre le polymorphisme de PAI-1 4 g/5G, est soit une alteration de la stabilisation de la plaque soit un effet toxique de t-PA. Conclusion Notre etude a montre une nature protectrice de genotype de PAI-1 4 g/4 g compare au genotype 5G/5G dans la survenue d’AIC.