Overweight/Obesity-related microstructural alterations of the fimbria-fornix in the ABCD study: The role of aerobic physical activity.

Childhood overweight/obesity has been associated with negative consequences related to brain function and may involve alterations in white matter pathways important for cognitive and emotional processing. Aerobic physical activity is a promising lifestyle factor that could restore white matter alterations. However, little is known about either regional white matter alterations in children with overweight/obesity or the effects of aerobic physical activity targeting the obesity-related brain alterations in children. Using a large-scale cross-sectional population-based dataset of US children aged 9 to 10 years (n = 8019), this study explored the associations between overweight/obesity and microstructure of limbic white matter tracts, and examined whether aerobic physical activity may reduce the overweight/obesity-related white matter alterations in children. The primary outcome measure was restriction spectrum imaging (RSI)-derived white matter microstructural integrity measures. The number of days in a week that children engaged in aerobic physical activity for at least 60 minutes per day was assessed. We found that females with overweight/obesity had lower measures of integrity of the fimbria-fornix, a major limbic-hippocampal white matter tract, than their lean peers, while this difference was not significant in males. We also found a positive relationship between the number of days of aerobic physical activity completed in a week and integrity measures of the fimbria-fornix in females with overweight/obesity. Our results provide cross-sectional evidence of sex-specific microstructural alteration in the fimbria-fornix in children with overweight/obesity and suggest that aerobic physical activity may play a role in reducing this alteration. Future work should examine the causal direction of the relationship between childhood overweight/obesity and brain alterations and evaluate potential interventions to validate the effects of aerobic physical activity on this relationship.

[White matter hyperintensities in ageing: Pathophysiology, associated cognitive disorders and prevention]. / Hypersignaux de la substance blanche chez la personne âgée : physiopathologie, troubles cognitifs associés et pistes de prévention.

White matter hyperintensities (WMH), also known as leukoaraïosis are very common neuroradiological manifestations in the elderly. The main risk factors for WMH are age and high blood pressure. The vascular origin of these lesions is classically accepted and WMH are considered as one feature of the small vessel disease. WMH may be associated with clinical symptoms, depending notably on their importance according to age. They are associated with increased mortality, strokes and changes in cognition with a higher risk of dementia (vascular dementia or Alzheimer's disease). Modification of vascular risk factors could have a beneficial effect, but few evidences from controlled trials are available.

Impact of leukoaraiosis on parenchymal hemorrhage in elderly patients treated with thrombolysis.

INTRODUCTION: Severity of vascular damage of white matter may predict hemorrhagic transformation (HT). We assess the relationship between leukoaraiosis (LA) severity and the type of hemorrhagic transformation in elderly patients treated with thrombolysis. METHODS: We retrospectively analyzed the clinical data and pretreatment magnetic resonance imaging (MRI) of 180 consecutive ischemic stroke patients aged over 75 years. LA severity was graded according to the Fazekas scale, and acute diffusion-weighted-imaging (DWI) lesion volumes were semi-automatically outlined. Predictors of hemorrhagic infarction (HI) and parenchymal hemorrhage (PH) were identified using logistic regression analysis and exact multinomial logistic analysis. RESULTS: HT occurred in 31 patients (17 %). Baseline National Institute of Health Stroke Score (NIHSS; p = 0.008), severe LA (p = 0.02), and diffusion lesion volume (p = 0.02) were predictors of HT in univariable logistic regression. Adjusted to lesion volume and baseline NIHSS score, exact multinomial logistic analysis showed that severe LA was the only independent predictor of parenchymal hemorrhage (p = 0.03). CONCLUSION: In elderly patients, LA severity better predicts parenchymal hemorrhage than infarct size.

Age-related cerebral white matter disease (leukoaraiosis): a review.

With the availability of improved brain imaging techniques, the high prevalence and clinical importance of cerebral small vessel disease have been increasingly recognised in recent years. As age is one of the most important risk factors for this condition, its prevalence is set to rise further as populations age. This may lead to an increase in the clinical consequences of white matter disease, namely cognitive decline, decreased mobility and increased stroke risk. Given the impact this will have on individuals and on healthcare systems, knowledge of the risk factors for small vessel disease, its prevention and its treatment is becoming more important. Although a lot of data are now available on the epidemiology, risk factors, clinical consequences and prognosis of leukoaraiosis, some of this information is conflicting. In this review, we summarise the current literature on cerebral small vessel disease, with an emphasis on its clinical aspects.

Gene-gene and gene-environment interplay represent specific susceptibility for different types of ischaemic stroke and leukoaraiosis.

Stroke is a very frequent entity. It is the third leading cause of death and the leading cause of adult disability in the developed world. At a population level, the common sporadic form of ischaemic stroke is underpinned by both environmental and genetic risk factors. Typically, in clinical practice, environmental risk factors such as hypertension, diabetes mellitus, smoking, alcohol consumption, and other factors, are usually considered to be more important than genetic factors. However, it is the interplay of both environmental and common genetic factors [such as the Leiden V, methylenetetrahydrofolate reductase C677T, apolipopotein E 4, endothelial nitric oxide synthase G894T, angiotensin-converting enzyme I/D and angiotensin II type 1 receptor A1166C mutations and polymorphisms] that leads to the development of ischaemic stroke. Indeed, a complex network of interactions between genetic factors and clinical risk factors can be supposed. This review evaluates the possible roles of gene-gene and gene-environment interactions concerning the above genetic factors in the evolution of ischaemic stroke and leukoaraiosis. A knowledge of the specific genetic patterns which are associated with a significant risk of ischaemic stroke or leukoaraiosis may also draw attention to a large population at an increased risk of circulatory disorders. This may facilitate the choice of more effective and specific prevention on the basis of the genotype.