by Río-Espínola AD, Fernández-Cadenas I, Rubiera M, Quintana M, Domingues-Montanari S, Mendióroz M, Fernández-Morales J, Giralt D, Molina CA, Alvarez-Sabín J, Montaner J.
Neurovascular Research Laboratory, Institut de Recerca, Hospital Vall d’Hebron, Pg Vall d’Hebron 119-129, 08035, Barcelona, Spain.
Pharmacogenomics. 2010 Jun;11(6):763-72.
PMID: 20504251

Abstract
AIMS: To find genetic predictors of reocclusion after successful fibrinolytic therapy during the acute phase of ischemic stroke.
PATIENTS & METHODS: This was a case-case prospective study analyzing 236 polymorphisms in a cohort of 222 patients treated with tissue plasminogen activator, from which 16 patients suffered a reocclusion event (7.2%). A predictive scale was generated using independent polymorphisms with a dominant/recessive model and tandem occlusion, weighted by their beta-coefficients in logistic regression.
RESULTS: Using a dominant/recessive model, the rs1800801 SNP from the MGP gene (odds ratio [OR]: 15.25; 95% CI: 2.23-104.46; adjusted p = 0.006) and the rs1883832 SNP from CD40 gene (OR: 0.077; 95% CI: 0.009-0.66; adjusted p = 0.019) were independently associated with reocclusion after logistic regression adjustment by clinical predictors. In an additive model, only the rs1883832 SNP (OR: 4.43; 95% CI: 1.62-12.15; adjusted p = 0.004) was related to reocclusion occurrence. The predictive model that was generated stratified the reocclusion risk from less than 1% to more than 70%. Reocclusions were associated with neurological worsening at 24 h (patients with reocclusion: 26.7%, versus patients without reocclusion: 4.9%; p = 0.002), as it was seen for MGP -7A>G (AA: 17.2% vs AG+GG: 4.5%; p = 0.027), but not for CD40 1C>T (CC: 4.5% vs CT+TT: 7.7%; p = 0.565). There was an association between CD40 -1C>T genotype and CD40 transcriptional activity in peripheral blood mononuclear cells (median expression values TT: 65.75%, CT: 70.80%, CC: 96.00%; p = 0.023). However, CD40 soluble fraction was not a useful biomarker of reocclusion status.
CONCLUSION: An association was found between MGP -7A>G and CD40 -1C>T polymorphisms, and reocclusion risk. The predictive scale that was generated permits the stratification of patients by their reocclusion risk with higher accuracy than clinical parameters alone.

Tags: Stroke Genetics

by Domingues-Montanari S, Fernandez-Cadenas I, Del Rio-Espinola A, Mendioroz M, Ribo M, Obach V, Marti-Fabregas J, Freijo M, Serena J, Corbeto N, Chacon P, Alvarez-Sabin J, Montaner J.
Neurovascular Research Laboratory and Neurovascular Unit. Neurology and Medicine Departments-Universitat Autonoma of Barcelona. Institute of Research of the Vall d’Hebron Hospital, Barcelona, Spain.
Eur J Neurol. 2010 Apr 9.
PMID: 20402757

Abstract
Background: The angiotensin-converting enzyme 1 (ACE1) gene has been extensively studied in stroke, yet generating conflicting results. The goal of our study was thus to clarify the influence of the ACE1 on the risk of suffering an ischaemic stroke (IS).
Methods: We genotyped the rs4341 (in linkage disequilibrium with the I/D polymorphism) of the ACE1 gene in 531 patients with IS and 549 healthy controls, and the rs1799752 (I/D polymorphism) in a subset of 68 patients with IS and 27 controls. We also performed functional studies by measuring serum ACE protein levels and enzymatic activity in 27 controls, 68 patients with IS at baseline and 35 patients with IS 24 h after onset of stroke symptoms.
Results: There was no association of the ACE1 variant with IS, although it affected ACE protein levels (P = 0.001). Indeed, patients with IS showed lower ACE levels than controls in the acute phase (115.9 +/- 38.9 vs. 174.1 +/- 56.1 ng/ml, P < 0.001), but not in the chronic phase (168.2 +/- 51.2, P = 0.673), and ACE protein levels did not differ between IS etiologies. Similar results were found for ACE activity.
Conclusions: The D allele of the ACE1 I/D and ACE protein levels was not associated with a higher risk of IS in Spanish individuals.

Tags: Stroke Genetics

by Domingues-Montanari S, Fernández-Cadenas I, Del Rio-Espinola A, Corbeto N, Krug T, Manso H, Gouveia L, Sobral J, Mendioroz M, Fernández-Morales J, Alvarez-Sabin J, Ribó M, Rubiera M, Obach V, Martí-Fàbregas J, Freijo M, Serena J, Ferro JM, Vicente AM, Oliveira SA, Montaner J.
Instituto Gulbenkian de Ciência, Oeiras, Portugal.
Cerebrovasc Dis. 2010 Mar 30;29(6):528-537.
PMID: 20357438

Abstract
BACKGROUND: Variants in the 5-lipoxygenase-activating protein (ALOX5AP) and phosphodiesterase 4D (PDE4D) genes have first been associated with ischemic stroke (IS) through whole-genome linkage screens. However, association studies obtained conflicting results. We aimed to investigate the contribution of selected single nucleotide polymorphisms (SNPs) in these genes for the first time in a large Iberian population.
METHODS: A case-control design was used to analyze one SNP in ALOX5AP and five SNPs in PDE4D in a total of 1,092 IS patients and 781 healthy controls of two different subsets from Spain and Portugal. The analysis was adjusted for confounding variables and the results were integrated in a meta-analysis of all case-control studies. In addition, ALOX5AP gene expression levels were determined in controls and IS cases.
RESULTS: A first meta-analysis of both subsets showed that the T allele of the SG13S114 SNP in ALOX5AP was a risk factor for IS after Bonferroni correction [OR = 1.22 (1.06-1.40); p = 0.006]. A second meta-analysis of white populations confirmed these results [OR = 1.18 (1.07-1.31); p = 0.001]. ALOX5AP gene expression analysis in a subset of controls and cases revealed that the SG13S114 genotypes modulate mRNA levels of ALOX5AP (p = 0.001) and mRNA levels were higher in IS cases (2.8 +/- 2.4%) than in controls (1.4 +/- 1.3%; p = 0.003). No association of the variants in PDE4D with IS was observed in our study.
CONCLUSIONS: The ALOX5AP SG13S114 variant is an independent risk factor for IS in the Iberian population and is associated with ALOX5AP expression levels. The role of this gene in stroke merits further investigation.
Copyright 2010 S. Karger AG, Basel.

Tags: Stroke Genetics

by Fernandez-Cadenas I, Del Rio-Espinola A, Rubiera M, Mendioroz M, Domingues-Montanari S, Cuadrado E, Hernandez-Guillamon M, Rosell A, Ribo M, Alvarez-Sabin J, Molina CA, Montaner J.
Neurovascular Research Laboratory and Neurovascular Unit. Department of Neurology of Vall d’Hebron University Hospital. Barcelona, Spain.
Int J Neurosci. 2010 Apr;120(4):245-51.
PMID: 20374070

Abstract
BACKGROUND: Despite t-PA proven benefits related to vessel reopening, up to 13% of stroke patients suffer reocclusions after t-PA. We aimed to analyze whether a functional polymorphism in a fibrinolysis inhibitor gene [plasminogen activator inhibitor-1 (PAI-1)] might be associated with reocclusion rates after stroke thrombolytic therapy.
METHODS: 165 patients with ischemic stroke who received t-PA < 3 h were studied. Reocclusion and recanalization was diagnosed by transcranial Doppler. PAI-1 4G/5G polymorphism determination was performed by sequencing. PAI-1 mRNA was studied by real-time PCR analysis. National institutes of health stroke scale (NIHSS) was serially measured since patients arrival to assess the neurological outcome, and modified ranking scale (mRS) at 3rd month was used to evaluate functional outcome following stroke.
RESULTS: PAI-1 4G/4G patients had higher reocclusion rates (4G/4G = 12.5% versus other genotypes = 2.7%, p = 0.025). . In a logistic regression, the 4G/4G genotype was the only factor associated with reocclusion (OR = 15.16 95%, CI = 1.4-163.4, p = 0.025). 4G/4G genotype was also associated with poor functional outcome at 3rd month (4G/4G = 4 versus others genotypes = 3, p = 0.017) and with mRNA levels at 12 h post stroke symptoms onset (4G/4G patients = 2.01% versus other genotypes = 0.68%, p = 0.034).
CONCLUSIONS: PAI-1 4G/4G genotype is associated with reocclusion rates and poor functional outcome among stroke patients treated with t-PA.

Tags: Stroke Genetics

by Domingues-Montanari S, Hernandez-Guillamon M, Fernandez-Cadenas I, Mendioroz M, Boada M, Munuera J, Rovira A, Maisterra O, Parés M, Gutierrez M, Alvarez-Sabin J, Chacón P, Delgado P, Montaner J.
Neurovascular Research Laboratory and Neurovascular Unit, Neurology and Medicine Departments, Universitat Autònoma de Barcelona, Institute of Research, Vall d’Hebron Hospital, Barcelona, Spain.
Neurobiol Aging. 2010 Apr 7.
PMID: 20381197

Abstract
Cerebral amyloid angiopathy (CAA) is a well-established cause of lobar intracerebral hemorrhage (ICH). The aim of the authors was to investigate the influence of clinical characteristics and genetic variants in the ACE, LRP, MMP9, Tafi, VEGFA, CYP11B2, A2M and APOE on ICH recurrence in a cohort of CAA-related ICH patients.
Sixty patients were enrolled and new symptomatic ICHs in the 36 mo following the index event were recorded. Leukoaraiosis degree, microbleeds count and variants in the APOE and ACE were associated with ICH recurrence. The rs4311 variant of the ACE was an independent risk factor (p = 0.001), resisting Bonferroni correction. Moreover, carriers of epsilon2 of the APOE and TT of the rs4311 of the ACE reached 100% recurrence before 18 mo (p < 0.001). Finally, ACE protein level was measured in serum of controls and depended on the rs4311 genotypes, TT carriers presenting higher level than CC carriers (p = 0.012).
These results suggest that variants in the ACE are associated with CAA-related ICH recurrence, possibly by modulating ACE protein level.
Copyright © 2010 Elsevier Inc. All rights reserved.

Tags: Stroke Genetics

by Arenillas JF, Massot A, Alvarez-Sabín J, Fernandez-Cadenas I, del Rio-Espinola A, Chacon P, Quintana M, Molina CA, Rovira A, Montaner J.
Neurovascular Unit, Department of Neurology, Universitat Autònoma de Barcelona, Barcelona, Spain.
Cerebrovasc Dis. 2009;28(1):95-102.
PMID: 19494488

Abstract
BACKGROUND: High levels of C-reactive protein (CRP) are associated with an increased risk of further ischemic events in patients with symptomatic intracranial atherosclerotic disease (ICAD). It remains unknown to which extent this increased risk might be genetically predetermined. We aimed to investigate the relationship between a common genetic polymorphism of the CRP gene and the risk of recurrent ischemic events in symptomatic ICAD patients.
METHODS: We studied 75 consecutive patients with a first-ever cerebral ischemic event attributable to symptomatic ICAD. Blood samples were drawn 3 months after the qualifying event. Genomic DNA was isolated and the C1444T single nucleotide polymorphism (SNP) of the CRP gene was determined. The blood concentration of CRP was also measured. Patients underwent long-term clinical follow-up to detect the occurrence of further major ischemic events.
RESULTS: During a median follow-up time of 23 months, 18 patients (24%) suffered a major ischemic event (10 ischemic strokes, 3 transient ischemic attacks and 5 myocardial infarctions). Raised CRP levels at baseline (p = 0.02) and the presence of the T allele within the CRP C1444T SNP were associated with a higher risk of recurrent ischemic events (p = 0.02). Kaplan-Meier and multivariable Cox regression analyses adjusted for age, sex, vascular risk factors and CRP level identified that the presence of the T allele in the studied polymorphism predicted the occurrence of further ischemic events (hazard ratio 3.6, 95% confidence interval 1.2-11.1; p = 0.025).
CONCLUSIONS: The presence of the T allele within the CRP gene C1444T polymorphism may be associated with a higher risk of further ischemic events in symptomatic ICAD patients.
(c) 2009 S. Karger AG, Basel.

Tags: Stroke Genetics

by Domingues-Montanari S, Fernández-Cadenas I, Del Río-Espinola A, Mendioroz M, Fernandez-Morales J, Corbeto N, Delgado P, Ribó M, Rubiera M, Obach V, Martí-Fàbregas J, Freijo M, Serena J, Montaner J.
Neurovascular Research Laboratory and Neurovascular Unit, Neurology and Medicine Departments-Universitat Autònoma de Barcelona, Vall d’Hebron Hospital, Passeig Vall d’Hebron 119-129, Barcelona, Spain.
Atherosclerosis. 2009 Jul 30.
PMID: 19647252

Abstract
BACKGROUND: Genetic factors contribute to the development of ischemic stroke (IS). In order to identify susceptibility variants, we analyzed single nucleotide polymorphisms (SNPs) that had been previously linked to stroke in a genome-wide association study.
METHODS: We analyzed 12 SNPs in a White population comprising IS patients and healthy controls. The analysis was adjusted for confounding variables and stratified by stroke etiology. Functional studies were then performed to elucidate the role of these variants in IS.
RESULTS: In a preliminary analysis of 268 controls and 531 IS cases, the rs10947803 SNP of KCNK17 (p=0.012) and the rs7506045 of IMPA2 (p=0.040) were associated with IS, although only the KCNK17 gene was an independent risk factor for IS. In a second phase, analysis of 271 new IS cases revealed that the A allele of rs10947803 was associated with stroke after correction for Bonferroni (OR=1.48; 95% CI, 1.14-1.91, p=0.003). Gene expression analysis revealed that KCNK17 mRNA levels were higher in the IS cases in the acute phase than in controls (14+/-78% vs. 91+/-41, p=0.002) but not in the chronic phase (56+/-57%; p=0.230). Moreover, RNA levels depended on the alleles of the rs10947803 SNP in the control group (p=0.021) and in the chronic phase (p=0.033).
CONCLUSIONS: The A allele of the rs10947803 variant of KCNK17 was associated with increased risk of IS and increased levels of KCNK17 gene expression. The role of this potassium channel gene in IS opens diagnostic and therapeutic expectations and merits further investigation.
Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.

Tags: Stroke Genetics

by Domingues-Montanari S, Mendioroz M, del Rio-Espinola A, Fernández-Cadenas I, Montaner J.
Departamento de Medicina, Neurovascular Research Laboratory and Neurovascular Unit, Universitat Autònoma de Barcelona, Institut de Recerca, Hospital Vall d’Hebron, 08035 Barcelona, Spain.
Expert Rev Mol Diagn. 2008 Jul;8(4):495-513.
PMID: 18598230

Abstract
Stroke is a multifactorial disease responsible for nearly 10% of deaths each year in industrialized countries. While some monogenic forms of stroke have been described, the vast majority result from the common polygenic form of the disease. Progress in molecular genetics has allowed the identification, through genome-wide linkage analysis, of various candidate genes, including the genes encoding PDE4D and ALOX5AP. Since then, genetic research has been extensively performed from single candidate genes to whole-genome scan studies, in parallel with the development of high-throughput technologies in molecular diagnostics. Additionally, the safety and efficacy of tissue plasminogen activator, the only approved therapy for the acute phase of stroke, is modulated by genetic background associated with the occurrence of hemorrhagic transformations and with the revascularization of the cerebral arteries. In the near future, understanding the contribution of stroke genetic factors will lead to improvements in prevention and treatments for neurovascular diseases.

Tags: Stroke Genetics