M. Mendioroz

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.

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.

Differentiating ischemic from hemorrhagic stroke using plasma biomarkers: The S100B/RAGE pathway

Although neuroimaging is useful in differentiating ischemic (IS) from hemorrhagic (ICH) stroke in the Emergency Department, a wide-available rapid biochemical test would add advantages in the pre-hospital triage and management of stroke patients. Our aim was to examine the predictive value of a panel of blood-borne biomarkers to differentiate IS from ICH. Admission blood samples obtained within 24h from stroke symptoms onset were tested by ELISA for CRP, D-dimer, sRAGE, MMP9, S100B, BNP, NT-3, caspase-3, chimerin-II, secretagogin, cerebellin and NPY. The complete protocol was achieved in 915 patients (776 IS, 139 ICH). Among blood samples obtained <6 h from symptoms onset (n=337), S100B levels were increased in ICH (107.58 vs 58.70 pg/mL; p<0.001) whereas sRAGE levels were decreased (0.77 vs 1.02 ng/mL; p=0.009) as compared to IS. In this subset of patients S100B (OR 3.97 95% CI 1.82-8.68; p=0.001) and sRAGE (OR 0.22 95% CI 0.10-0.52; p<0.001) were independently associated with ICH. A regression tree was created by CART method showing good classification ability (AUC=0.762). Similar results were found for samples obtained within 3 h. In conclusion, a combination of biomarkers including those of the S100B/RAGE pathway seems promising to achieve a rapid biochemical diagnosis of IS versus ICH in the first hours from symptoms onset. This article is part of a Special Issue entitled: Translational Proteomics.

Influence of thrombin‐activatable fibrinolysis inhibitor and plasminogen activator inhibitor‐1 gene polymorphisms on tissue‐type plasminogen activator‐induced recanalization in ischemic stroke patients

Summary.  Objective: Endogenous resistance to tissue‐type plasminogen activator (t‐PA) might decrease the benefit of thrombolysis‐induced recanalization. Thrombin‐activatable fibrinolysis inhibitor (TAFI) and plasminogen activator inhibitor‐1 (PAI‐1) are fibrinolysis inhibitors. TAFI removes residues from partially degraded fibrin that in turn eliminates plasminogen binding sites; PAI‐1 directly inhibits the activity of t‐PA. We aimed to study whether the presence of two common functional polymorphisms of the TAFI and PAI‐1 genes influence rates of recanalization of the middle cerebral artery (MCA) among t‐PA‐treated stroke patients. Methods and results: TAFI and PAI‐1 polymorphism determinations were performed by restriction fragment length polymorphism mapping and conventional sequencing in 139 patients with strokes involving the MCA and who received t‐PA within 3 h. Recanalization was diagnosed by means of transcranial Doppler. No association was found between PAI‐1 4 G/5 G polymorphism and recanalization rate. Dyslipidemia and TAFI Thr325Ile polymorphism were the main variables associated with recanalization resistance by the end of t‐PA infusion: odds ratio (OR) 4.1 [95% confidence interval (95% CI) 1.6–10.8, P = 0.003] and OR 5.6 (95% CI 1.2–20, P = 0.031), respectively. The combination of the two polymorphisms doubled the risk of absence of recanalization: OR 11.1 (95% CI 1.4–89.8, P = 0.025). Conclusions: Polymorphic fibrinolysis inhibitor genes influence t‐PA‐induced recanalization resistance in ischemic stroke patients, especially when coexisting in the same patient. Efforts to individualize thrombolytic treatments are required.

Caspase-3 is related to infarct growth after human ischemic stroke.

Our aim was to investigate caspase-3 plasma levels after stroke, its correlation with infarct expansion and neurological outcome. Caspase-3 plasma levels were determined by ELISA at different time points after stroke in 116 t-PA-treated patients and a control group of 40 healthy controls. Neurological status was evaluated by NIHSS scores and functional outcome by modified Rankin Scale. To assess brain infarct growth, serial brain magnetic resonance imaging scans including diffusion- (DWI) and perfusion-weighted (PWI) images were performed in a subgroup of 58 patients. Plasma caspase-3 levels were higher in stroke patients versus the control group throughout the acute phase of stroke. Furthermore, caspase-3 level at 24h was associated with poorer short- and long-term neurological outcome and positively correlated with infarct growth assessed by diffusion-weighted images. Our data suggest that caspase-3 could be involved in recruitment of ischemic brain tissue being a marker of infarct growth.

Brain Natriuretic Peptide Is Associated with Worsening and Mortality in Acute Stroke Patients but Adds No Prognostic Value to Clinical Predictors of Outcome

Background: At the present time, the determination of the outcome of stroke patients is based on the analysis of clinical and neuroimaging data. The use of prognostic blood biomarkers could aid in decision-making processes, e.g. admitting patients to specialized stroke units. Although the prognostic role of natriuretic peptides has been studied in heart failure and coronary diseases, the value of brain natriuretic peptide (BNP) is less known within the field of strokes. Objective: We aimed to study the relationship between plasma levels of BNP and acute neurological worsening or mortality after stroke in a large cohort of patients (investigating both ischemic and hemorrhagic disease). Methods: Consecutive stroke patients (ischemic and hemorrhagic) admitted to the Stroke Unit of our University Hospital within 24 h of the onset of symptoms were included. Stroke severity was assessed according to the National Institutes of Health Stroke Scale (NIHSS) at admission and at discharge. Neurological worsening was defined as an increase of 4 or more points in the NIHSS score or death during the patient’s stay at the Stroke Unit. Blood samples were drawn upon admission to measure plasma levels of BNP (Biosite Inc., San Diego, Calif., USA). Statistical analysis was performed using SPSS 15.0 and R software. Results: Altogether, 896 patients were included in the study. BNP plasma levels were higher among patients who deteriorated the most over time (n = 112; 90.5 vs. 61.2 ng/l; p = 0.006) or died (n = 83; 118.2 vs. 60.9 ng/l; p < 0.001). Multivariate logistic regression analysis indicated that plasma BNP level was an independent predictor of neurological worsening [BNP >56.7 ng/l; odds ratio (OR) = 1.64; p = 0.04] and death after stroke (BNP >65.3 ng/l; OR = 1.97; p = 0.034). Adding BNP level to other well-known clinical predictors of bad outcome did not significantly increase the predictive value. Conclusions: Plasma levels of BNP measured during the acute phase of stroke are associated both with early neurological worsening and mortality. However, this biological information does not supply prognostic information which would add to clinical variables, which limits its use as a biomarker. Further investigation and systematic reviews are needed to clarify the role of natriuretic peptides in stroke outcome.

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.