Cognitive performance in asymptomatic carriers of mutations R1031C and R141C in CADASIL

CADASIL is the most common hereditary cause of repeated ischemic strokes, and has also been identified as a model of pure vascular dementia. The objective of this study was to establish the cognitive performance of asymptomatic carriers with the mutations R1031C and R141C. This observational cross-sectional analytical study divided subjects into three groups: asymptomatic carriers of the R1031C mutation (n = 39), asymptomatic carries of the R141C mutation (n = 8) and non-carriers (n = 50). Statistically significant differences were found (p <0.05) between the group of the R1031C mutation and the non-carriers in constructional praxis, executive function and abstract reasoning. For the R141C mutation, scores below expected values in executive function and mental calculation were observed. It is concluded that asymptomatic carriers of the two mutations showed low performance in working memory, mental abstraction and processing speed, which could be associated with preclinical cognitive biomarkers preceding the presentation of the first vascular event

Characterization of cells from patient-derived fibrovascular membranes in proliferative diabetic retinopathy

Purpose Epiretinal fibrovascular membranes (FVMs) are a hallmark of proliferative diabetic retinopathy (PDR). Surgical removal of FVMs is often indicated to treat tractional retinal detachment. This potentially informative pathological tissue is usually disposed of after surgery without further examination. We developed a method for isolating and characterizing cells derived from FVMs and correlated their expression of specific markers in culture with that in tissue. Methods: FVMs were obtained from 11 patients with PDR during diabetic vitrectomy surgery and were analyzed with electron microscopy (EM), comparative genomic hybridization (CGH), immunohistochemistry, and/or digested with collagenase II for cell isolation and culture. Antibody arrays and enzyme-linked immunosorbent assay (ELISA) were used to profile secreted angiogenesis-related proteins in cell culture supernatants. Results: EM analysis of the FVMs showed abnormal vessels composed of endothelial cells with large nuclei and plasma membrane infoldings, loosely attached perivascular cells, and stromal cells. The cellular constituents of the FVMs lacked major chromosomal aberrations as shown with CGH. Cells derived from FVMs (C-FVMs) could be isolated and maintained in culture. The C-FVMs retained the expression of markers of cell identity in primary culture, which define specific cell populations including CD31-positive, alpha-smooth muscle actin-positive (SMA), and glial fibrillary acidic protein-positive (GFAP) cells. In primary culture, secretion of angiopoietin-1 and thrombospondin-1 was significantly decreased in culture conditions that resemble a diabetic environment in SMA-positive C-FVMs compared to human retinal pericytes derived from a non-diabetic donor. Conclusions: C-FVMs obtained from individuals with PDR can be isolated, cultured, and profiled in vitro and may constitute a unique resource for the discovery of cell signaling mechanisms underlying PDR that extends beyond current animal and cell culture models

Resistance to autosomal dominant Alzheimer's disease in an APOE3 Christchurch homozygote: a case report.

We identified a PSEN1 (presenilin 1) mutation carrier from the world's largest autosomal dominant Alzheimer's disease kindred, who did not develop mild cognitive impairment until her seventies, three decades after the expected age of clinical onset. The individual had two copies of the APOE3 Christchurch (R136S) mutation, unusually high brain amyloid levels and limited tau and neurodegenerative measurements. Our findings have implications for the role of APOE in the pathogenesis, treatment and prevention of Alzheimer's disease

Exceptionally low likelihood of Alzheimer's dementia in APOE2 homozygotes from a 5,000-person neuropathological study.

Each additional copy of the apolipoprotein E4 (APOE4) allele is associated with a higher risk of Alzheimer's dementia, while the APOE2 allele is associated with a lower risk of Alzheimer's dementia, it is not yet known whether APOE2 homozygotes have a particularly low risk. We generated Alzheimer's dementia odds ratios and other findings in more than 5,000 clinically characterized and neuropathologically characterized Alzheimer's dementia cases and controls. APOE2/2 was associated with a low Alzheimer's dementia odds ratios compared to APOE2/3 and 3/3, and an exceptionally low odds ratio compared to APOE4/4, and the impact of APOE2 and APOE4 gene dose was significantly greater in the neuropathologically confirmed group than in more than 24,000 neuropathologically unconfirmed cases and controls. Finding and targeting the factors by which APOE and its variants influence Alzheimer's disease could have a major impact on the understanding, treatment and prevention of the disease

Factores genéticos y no-genéticos asociados a CADASIL: estudio de cohorte retrospectivo

ABSTRACT: Objective: To examine the relationships between genetic variables (genotype–phenotype) and cardiovascular risk factors in the natural history of CADASIL. Methods: This was a retrospective cohort study of 331 individuals, 90 were carriers of four mutations in the NOTCH3 gene. Cox proportional hazards models were fitted to estimate the effect of genetic and cardiovascular factors on the onset of migraine, first stroke, and dementia. Competing risk regression models considered death as risk. Results: Noncarriers and NOTCH3 mutation carriers had similar frequencies for all cardiovascular risk factors. Diabetes (SHR 3.5, 95% CI 1.75–7.15) was associated with a younger age at onset of strokes among carriers. Additionally, a genotype–phenotype relationship was observed among C455R mutation carriers, with higher frequency of migraines (100%), younger age at onset of migraine (median age 7 years, IQR 8) and cerebrovascular events (median age 30.5 years, IQR 26). Moreover, fewer carriers of the R141C mutation exhibited migraines (20%), and it was even lower than the frequency observed in the noncarrier group (44.8%). Conclusions: This study characterizes extended family groups, allowing us a comparison in the genotype–phenotype. The results suggest a complex interplay of genetic and cardiovascular risk factors that may help explain the variability in the clinical presentation and severity of CADASILRESUMEN: Objetivo: Examinar las relaciones entre variables genéticas (genotipo-fenotipo) y factores de riesgo cardiovascular en la historia natural de CADASIL. Métodos: Este fue un estudio de cohorte retrospectivo de 331 individuos, 90 eran portadores de cuatro mutaciones en el gen NOTCH3. Se ajustaron modelos de riesgos proporcionales de Cox para estimar el efecto de factores genéticos y cardiovasculares sobre la aparición de migraña, primer accidente cerebrovascular y demencia. Los modelos de regresión de riesgo en competencia consideraron la muerte como riesgo. Resultados: Los no portadores y los portadores de la mutación NOTCH3 tuvieron frecuencias similares para todos los factores de riesgo cardiovascular. La diabetes (SHR 3,5; IC del 95%: 1,75 a 7,15) se asoció con una edad más temprana al inicio de los accidentes cerebrovasculares entre los portadores. Además, se observó una relación genotipo-fenotipo entre los portadores de la mutación C455R, con mayor frecuencia de migrañas (100%), menor edad al inicio de la migraña (mediana de edad de 7 años, IQR 8) y eventos cerebrovasculares (mediana de edad de 30,5 años, IQR 26 ). Además, menos portadores de la mutación R141C presentaron migrañas (20%), y fue incluso menor que la frecuencia observada en el grupo no portador (44,8%). Conclusiones: Este estudio caracteriza a los grupos familiares extensos, lo que nos permite una comparación en el genotipo-fenotipo. Los resultados sugieren una interacción compleja de factores de riesgo genéticos y cardiovasculares que pueden ayudar a explicar la variabilidad en la presentación clínica y la gravedad de CADASIL

Specific Abnormalities in White Matter Pathways as Interface to Small Vessels Disease and Cognition in Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy Individuals

Background: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is characterized by leukoencephalopathy leading to cognitive impairment. Subtle cognitive deficits can be observed early in the course of the disease, before the occurrence of the first stroke. Therefore, markers that can predict disease progression at this early stage, when interventions are likely to alter disease course, are needed. We aimed to examine the biological cascade of microstructural and macrostructural white matter (WM) abnormalities underlying cognitive deficits in CADASIL.Methods: We examined 20 nondemented CADASIL mutation carriers and 23 noncarriers who underwent neuropsychological evaluation and magnetic resonance imaging. Using probabilistic tractography of key WM tracts, we examined group differences in diffusivity measures and WM hyperintensity volume. Successive mediation models examined whether tract-specific WM abnormalities mediated subtle cognitive differences between CADASIL mutation carriers and noncarriers.Results: The largest effect size differentiating the two groups was observed for left superior longitudinal fasciculus-temporal (SLFt) diffusivity (Cohen's f = 0.49). No group differences were observed with a global diffusion measure. These specific microstructural differences in the SLFt were associated with higher WM hyperintensities burden, and subtle executive deficits in CADASIL mutation carriers.Discussion: Worse diffusivity in the left SLFt is related to greater severity of small vessel disease and worse executive functioning in the asymptomatic stage of the disease. Worse diffusivity of the left SLFt may potentially hold promise as an indicator of disease progression. Impact statementDiffusion tensor imaging outperforms conventional imaging of subcortical small vessel disease as a potential marker of future disease progression. Here we identified the left superior longitudinal temporal fasciculus as a critical white matter fiber bundle, of which worse diffusivity can link presence of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy mutations to greater severity of small vessel disease and worse executive functioning in asymptomatic stages of the disease. This tract may hold promise and deserves further examination as an early indicator of disease progression

Effect of Methotrexate on an In Vitro Patient-Derived Model of Proliferative Vitreoretinopathy

Purpose The purpose of this study was to develop a method for isolating, culturing, and characterizing cells from patient-derived membranes in proliferative vitreoretinopathy (PVR) to be used for drug testing. Methods: PVR membranes were obtained from six patients with grade C PVR. Membrane fragments were analyzed by gross evaluation, fixed for immunohistologic studies to establish cell identity, or digested with collagenase II to obtain single cell suspensions for culture. PVR-derived primary cultures were used to examine the effects of methotrexate (MTX) on proliferation, migration, and cell death. Results: Gross analysis of PVR membranes showed presence of pigmented cells, indicative of retinal pigment epithelial cells. Immunohistochemistry identified cells expressing α-smooth muscle actin, glial fibrillary acidic protein, Bestrophin-1, and F4/80, suggesting the presence of multiple cell types in PVR. Robust PVR primary cultures (C-PVR) were successfully obtained from human membranes, and these cells retained the expression of cell identity markers in culture. C-PVR cultures formed membranes and band-like structures in culture reminiscent of the human condition. MTX significantly reduced the proliferation and band formation of C-PVR, whereas it had no significant effect on cell migration. MTX also induced regulated cell death within C-PVR as assessed by increased expression of caspase-3/7. Conclusions: PVR cells obtained from human membranes can be successfully isolated, cultured, and profiled in vitro. Using these primary cultures, we identified MTX as capable of significantly reducing growth and inducing cell death of PVR cells in vitro