Sophie Domingues-Montanari

A large screening of angiogenesis biomarkers and their association with neurological outcome after ischemic stroke.

BACKGROUND The induction of angiogenesis after stroke may enhance neurorestorative processes. Our aim was to examine the endogenous angiogenesis balance and their association with long-term clinical outcome in ischemic stroke patients. METHODS A total of 109 stroke subjects were included in the study. Firstly, plasma samples were obtained from control subjects (n = 26) and tPA-treated stroke patients (n = 29) at baseline (within 3h of symptoms onset), 1, 2, 12, 24h after tPA treatment, at discharge and 3 months after the ischemic event. Angiogenic promoters (PDGF-AA, PDGF-BB, HGF, FGF, KGF, HB-EGF, TPO, VEGF, VEGFR-1, VEGFR-2 and SDF-1α) and inhibitors (endostatin, angiostatin, thrombospondin-1 and thrombospondin-2) were analyzed by Searchlight(®) technology or ELISA. Additionally, baseline and 24h endostatin plasma level was determined in a new set of stroke patients (n = 80). Clinical parameters (NIHSS, mRS, mortality and hemorrhagic transformation events) were assessed to evaluate outcome. RESULTS Baseline PDGF-BB, endostatin and thrombospondin-2 levels were higher in stroke patients than in controls (p < 0.05). A pro-angiogenic balance was associated with lower NIHSS scores and less intracranial hemorrhagic complications. Interestingly, a high baseline endostatin level was associated to long-term functional dependency (mRS > 2; p = 0.004). Finally, a baseline endostatin cut-off point of 184 ng/mL was an independent predictor of functional dependency at three months in the multiple logistic regression with an odds ratio of 8.9 (95% CI: 2.7-28.8; p = 0.0002). CONCLUSIONS Our results indicate that an early pro-angiogenic balance is associated with mild short-term neurological deficit, while an acute anti-angiogenesis status determined by high endostatin plasma level predicts a worse long-term functional outcome.

A missense HTRA1 mutation expands CARASIL syndrome to the Caucasian population

M. Mendioroz, MD* I. Fernández-Cadenas, PhD* A. del Río-Espinola* A. Rovira, MD E. Solé, PhD M.T. Fernández-Figueras, MD, PhD V. García-Patos, MD, PhD J. Sastre-Garriga, MD, PhD S. Domingues-Montanari J. Álvarez-Sabín, MD, PhD J. Montaner, MD, PhD A MISSENSE HTRA1 MUTATION EXPANDS CARASIL SYNDROME TO THE CAUCASIAN POPULATION Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) (MIM 600142) is a heritable small vessel disease clinically characterized by nonhypertensive leukoencephalopathy associated with alopecia and spondylosis.1-3 First described by Maeda et al.2 in 1965, cases exclusively come from Japan and China.3,4 Beginning in young adulthood, patients develop progressive motor and cognitive impairment and usually die within 10 years.1 Centrifugally enlarged arteries with widespread loss of both medial smooth muscle cells and mural extracellular matrix are observed in the white matter and leptomeninges.5 In July 2009, Hara et al.6 described the HtrA serine protease 1 gene (HTRA1) as the causative gene of CARASIL. Here we report for the first time a Caucasian patient with CARASIL harboring a novel HTRA1 mutation.

Genetics of stroke: a review of recent advances.

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.

Association of a genetic variant in the ALOX5AP with higher risk of ischemic stroke: a case-control, meta-analysis and functional study.

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.

MMP-2/MMP-9 plasma level and brain expression in cerebral amyloid angiopathy-associated hemorrhagic stroke.

Cerebral amyloid angiopathy (CAA) is one of the main causes of intracerebral hemorrhage (ICH) in the elderly. Matrix metalloproteinases (MMPs) have been implicated in blood–brain barrier disruption and ICH pathogenesis. In this study, we determined the levels MMP‐2 and MMP‐9 in plasma and their brain expression in CAA‐associated hemorrhagic stroke. Although MMP‐2 and MMP‐9 plasma levels did not differ among patients and controls, their brain expression was increased in perihematoma areas of CAA‐related hemorrhagic strokes compared with contralateral areas and nonhemorrhagic brains. In addition, MMP‐2 reactivity was found in β‐amyloid (Aβ)‐damaged vessels located far from the acute ICH and in chronic microbleeds. MMP‐2 expression was associated to endothelial cells, histiocytes and reactive astrocytes, whereas MMP‐9 expression was restricted to inflammatory cells. In summary, MMP‐2 expression within and around Aβ‐compromised vessels might contribute to the vasculature fatal fate, triggering an eventual bleeding.

The gender gap in stroke: a meta-analysis

Giralt D, Domingues‐Montanari S, Mendioroz M, Ortega L, Maisterra O, Perea‐Gainza M, Delgado P, Rosell A, Montaner J. The gender gap in stroke: a meta‐analysis. 
Acta Neurol Scand: 2012: 125: 83–90. 
© 2011 John Wiley & Sons A/S.

Brain Perihematoma Genomic Profile Following Spontaneous Human Intracerebral Hemorrhage

Background Spontaneous intracerebral hemorrhage (ICH) represents about 15% of all strokes and is associated with high mortality rates. Our aim was to identify the gene expression changes and biological pathways altered in the brain following ICH. Methodology/Principal Findings Twelve brain samples were obtained from four deceased patients who suffered an ICH including perihematomal tissue (PH) and the corresponding contralateral white (CW) and grey (CG) matter. Affymetrix GeneChip platform for analysis of over 47,000 transcripts was conducted. Microarray Analysis Suite 5.0 was used to process array images and the Ingenuity Pathway Analysis System was used to analyze biological mechanisms and functions of the genes. We identified 468 genes in the PH areas displaying a different expression pattern with a fold change between −3.74 and +5.16 when compared to the contralateral areas (291 overexpressed and 177 underexpressed). The top genes which appeared most significantly overexpressed in the PH areas codify for cytokines, chemokines, coagulation factors, cell growth and proliferation factors while the underexpressed codify for proteins involved in cell cycle or neurotrophins. Validation and replication studies at gene and protein level in brain samples confirmed microarray results. Conclusions The genomic responses identified in this study provide valuable information about potential biomarkers and target molecules altered in the perihematomal regions.

TTC7B emerges as a novel risk factor for ischemic stroke through the convergence of several genome-wide approaches

We hereby propose a novel approach to the identification of ischemic stroke (IS) susceptibility genes that involves converging data from several unbiased genetic and genomic tools. We tested the association between IS and genes differentially expressed between cases and controls, then determined which data mapped to previously reported linkage peaks and were nominally associated with stroke in published genome-wide association studies. We first performed gene expression profiling in peripheral blood mononuclear cells of 20 IS cases and 20 controls. Sixteen differentially expressed genes mapped to reported whole-genome linkage peaks, including the TTC7B gene, which has been associated with major cardiovascular disease. At the TTC7B locus, 46 tagging polymorphisms were tested for association in 565 Portuguese IS cases and 520 controls. Markers nominally associated in at least one test and defining associated haplotypes were then examined in 570 IS Spanish cases and 390 controls. Several polymorphisms and haplotypes in the intron 5–intron 6 region of TTC7B were also associated with IS risk in the Spanish and combined data sets. Multiple independent lines of evidence therefore support the role of TTC7B in stroke susceptibility, but further work is warranted to identify the exact risk variant and its pathogenic potential.

A predictive clinical–genetic model of tissue plasminogen activator response in acute ischemic stroke

Wide interindividual variability exists in response to tissue plasminogen activator (t‐PA) treatment in the acute phase of ischemic stroke. We aimed to find genetic variations associated with hemorrhagic transformation (HT) and mortality rates after t‐PA. We then generated a clinical–genetic model for predicting t‐PA response.

ACE variants and risk of intracerebral hemorrhage recurrence in amyloid angiopathy

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 ε2 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.