P-selectin 1087G/A polymorphism is associated with neuropsychological test performance in older adults with cardiovascular disease

Spontaneous white matter damage, cognitive decline and neuroinflammation in middle-aged hypertensive rats: an animal model of early-stage cerebral small vessel disease

Introduction

Cerebral small vessel disease (cSVD) is one of the most prevalent neurological disorders. The progressive remodeling of brain microvessels due to arterial hypertension or other vascular risk factors causes subtle, but constant cognitive decline through to manifest dementia and substantially increases the risk for stroke. Preliminary evidence suggests the contribution of the immune system to disease initiation and progression, but a more detailed understanding is impaired by the unavailability of appropriate animal models. Here, we introduce the spontaneously hypertensive rat (SHR) as a model for early onset cSVD and unveiled substantial immune changes in conjunction with brain abnormalities that resemble clinical findings.

Results

In contrast to age-matched normotensive Wistar Kyoto (WKY) rats, male SHR exhibited non-spatial memory deficits. Magnetic resonance imaging showed brain atrophy and a reduction of white matter volumes in SHR. Histological analyses confirmed white matter demyelination and unveiled a circumscribed blood brain barrier dysfunction in conjunction with micro- and macrogliosis in deep cortical regions. Flow cytometry and histological analyses further revealed substantial disparities in cerebral CD45high leukocyte counts and distribution patterns between SHR and WKY. SHR showed lower counts of T cells in the choroid plexus and meningeal spaces as well as decreased interleukin-10 levels in the cerebrospinal fluid. On the other hand, both T and NK cells were significantly augmented in the SHR brain microvasculature.

Conclusions

Our results indicate that SHR share behavioral and neuropathological characteristics with human cSVD patients and further undergird the relevance of immune responses for the initiation and progression of cSVD.

Electronic supplementary material

The online version of this article (doi:10.1186/s40478-014-0169-8) contains supplementary material, which is available to authorized users.

P-selectin Expression Tracks Cerebral Atrophy in Mexican-Americans

Background and Purpose: We hypothesized that the P-selectin (SELP) gene, localized to a region on chromosome 1q24, pleiotropically contributes to increased blood pressure and cerebral atrophy. We tested this hypothesis by performing genetic correlation analyses for 13 mRNA gene expression measures from P-selectin and 11 other genes located in 1q24 region and three magnetic resonance imaging derived indices of cerebral integrity. Methods: The subject pool consisted of 369 (219F; aged 28–85, average = 47.1 ± 12.7 years) normally aging, community-dwelling members of large extended Mexican-American families. Genetic correlation analysis decomposed phenotypic correlation coefficients into genetic and environmental components among 13 leukocyte-based mRNA gene expressions and three whole-brain and regional measurements of cerebral integrity: cortical gray matter thickness, fractional anisotropy of cerebral white matter, and the volume of hyperintensive WM lesions. Results: From the 13 gene expressions, significant phenotypic correlations were only found for the P- and L-selectin expression levels. Increases in P-selectin expression levels tracked with decline in cerebral integrity while the opposite trend was observed for L-selectin expression. The correlations for the P-selectin expression were driven by shared genetic factors, while the correlations with L-selectin expression were due to shared environmental effects. Conclusion: This study demonstrated that P-selectin expression shared a significant variance with measurements of cerebral integrity and posits elevated P-selectin expression levels as a potential risk factor of hypertension-related cerebral atrophy.

Vascular cognitive impairment (VCI): Progress towards knowledge and treatment

Until recently, the study of cognitive impairment as a manifestation of cerebrovascular disease (CVD) has been hampered by the lack of common standards for assessment. The term vascular cognitive impairment (VCI) encompasses all levels of cognitive decline associated with CVD from mild deficits in one or more cognitive domains to crude dementia syndrome. VCI incorporates the complex interactions among classic vascular risk factors (i.e. arterial hypertension, high cholesterol, and diabetes), CVD subtypes, and Alzheimer's Disease (AD) pathology. VCI may be the earliest, commonest, and subtlest manifestation of CVD and can be regarded as a highly prevalent and preventable syndrome. However, cognition is not a standardized outcome measure in clinical trials assessing functional ability after stroke. Furthermore, with the exception of anti-hypertensive medications, the impact of either preventive or acute stroke treatments on cognitive outcome is not known. Although clinical, epidemiological, neuroimaging, and experimental data support the VCI concept, there is a lack of integrated knowledge on the role played by the most relevant pathophysiological mechanisms involved in several neurological conditions including stroke and cognitive impairment such as excitotoxicity, apoptosis, mitochondrial DNA damage, oxidative stress, disturbed neurotransmitter release, and inflammation. For this reason, in 2006 the National Institute of Neurological Disorders and Stroke (NINDS) and the Canadian Stroke Network (CSN) defined a set of data elements to be collected in future studies aimed at defining VCI etiology, clinical manifestations, predictive factors, and treatment. These recommendations represent the first step toward developing diagnostic criteria for VCI based on sound knowledge rather than on hypotheses. The second step will be to integrate all studies using the agreed methodologies. This is likely to accelerate the search for answers.