The Siblings With Ischemic Stroke Study (SWISS) Protocol

BACKGROUND: Family history and twins studies suggest an inherited component to ischemic stroke risk. Candidate gene association studies have been performed but have limited capacity to identify novel risk factor genes. The Siblings With Ischemic Stroke Study (SWISS) aims to conduct a genome-wide scan in sibling pairs concordant or discordant for ischemic stroke to identify novel genetic risk factors through linkage analysis. METHODS: Screening at multiple clinical centers identifies patients (probands) with radiographically confirmed ischemic stroke and a family history of at least 1 living full sibling with stroke. After giving informed consent, without violating privacy among other family members, the proband invites siblings concordant and discordant for stroke to participate. Siblings then contact the study coordinating center. The diagnosis of ischemic stroke in potentially concordant siblings is confirmed by systematic centralized review of medical records. The stroke-free status of potentially discordant siblings is confirmed by validated structured telephone interview. Blood samples for DNA analysis are taken from concordant sibling pairs and, if applicable, from 1 discordant sibling. Epstein-Barr virus-transformed lymphoblastoid cell lines are created, and a scan of the human genome is planned. DISCUSSION: Conducting adequately powered genomics studies of stroke in humans is challenging because of the heterogeneity of the stroke phenotype and the difficulty of obtaining DNA samples from clinically well-characterized members of a cohort of stroke pedigrees. The multicentered design of this study is intended to efficiently assemble a cohort of ischemic stroke pedigrees without invoking community consent or using cold-calling of pedigree members

Stable runoff and weathering fluxes into the oceans over Quaternary climate cycles

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Adaptive metabolic changes in CADASIL white matter

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an important genetic cause of stroke, but pathogenic mechanisms and functional alterations remain poorly characterized. The purpose of this study was to investigate adaptive metabolic and functional changes in white matter hyperintensities and normal-appearing white matter in CADASIL patients using (1)H-magnetic resonance spectroscopic imaging (MRSI). Eight CADASIL patients and eight matched healthy controls were studied. (1)H-MRSI data were acquired on a 3T scanner using high-resolution multi-spin echo spectroscopic imaging (T (E) = 288 ms) and non-accelerated medium-resolution MRSI (T (E) = 35 ms). MRI of all CADASIL patients demonstrated characteristic white matter hyper-intensities (WMH) in the subcortical periventricular white matter. Cre/Cho, Glx/Cho and Glx/Cre ratios were significantly decreased in WMH compared to normal-appearing white matter (NAWM) in patients, while Glx/Cre and mI/Cho ratios in NAWM showed a significant increase compared to healthy controls. In severely affected patients derived spectra reflected a decrease of NAA concentrations inside WMH when compared to healthy white matter. Metabolic abnormalities in WMH of CADASIL patients are compatible with axonal loss due to chronic micro-infarctions. Increased Glx/Cre and mI/Cho ratios in NAWM indicate an augmented glial cell density and decreased neuronal cell density. This altered tissue composition might be interpreted as adaptation to hypoperfusion and impaired vasoreactivity in NAWM of CADASIL patients. Our data might contribute to the general understanding of adaptive processes induced by hypoperfusion and chronic ischemia