Association of Cardiovascular Risk Factors with Cerebral Perfusion in Whites and African Americans.

BACKGROUND: Midlife cardiovascular risk factors increase risk for Alzheimer's disease (AD). Despite disproportionately high cardiovascular disease and dementia rates, African Americans are under-represented in studies of AD risk and research-based guidance on targeting vascular risk factors is lacking. OBJECTIVE: This study investigated relationships between specific cardiovascular risk factors and cerebral perfusion in White and African American adults enriched for AD risk. METHODS: Participants included 397 cognitively unimpaired White (n = 330) and African American (n = 67) adults enrolled in the Wisconsin Alzheimer's Disease Research Center who underwent pseudo-continuous arterial spin labeling MRI. Multiple linear regression models examined independent relationships between cardiovascular risk factors and mean cerebral perfusion. Subsequent interaction and stratified models assessed the role for APOE genotype and race. RESULTS: When risk factor p-values were FDR-adjusted, diastolic blood pressure was significantly associated with mean perfusion. Tobacco use, triglycerides, waist-to-hip ratio, and a composite risk score were not associated with perfusion. Without FDR adjustment, a relationship was also observed between perfusion and obesity, cholesterol, and fasting glucose. Neither APOE genotype nor race moderated relationships between risk factors and perfusion. CONCLUSION: Higher diastolic blood pressure predicted lower perfusion more strongly than other cardiovascular risk factors. This relationship did not vary by racial group or genetic risk for AD, although the African American sample had greater vascular risk burden and lower perfusion rates. Our findings highlight the need to prioritize inclusion of underrepresented groups in neuroimaging studies and to continue exploring the link between modifiable risk factors, cerebrovascular health, and AD risk in underrepresented populations.

Polypharmacy in multiple sclerosis: relationship with fatigue, perceived cognition, and objective cognitive performance.

OBJECTIVE: Patients with multiple sclerosis (MS) commonly use a variety of medications to slow disease progression, alleviate symptoms, and treat comorbid conditions. Polypharmacy has been linked to adverse outcomes in other patient groups, but has not been studied extensively in MS. We investigated the impact of polypharmacy on fatigue, objective neuropsychological performance, and subjective cognitive impairment in a sample of patients with MS. METHODS: MS patients (n=85) completed a medication inventory, self-report questionnaires, and a battery of neurocognitive tests. MS patients with polypharmacy were compared to MS patients without polypharmacy, using multivariate analysis of covariance (MANCOVA). RESULTS: After controlling for disease characteristics, MS patients with polypharmacy (n=28) exhibited prospective memory deficits and reported significantly more fatigue and subjective cognitive problems than MS patients without polypharmacy. CONCLUSION: Clinicians and patients should carefully weigh the costs and benefits of prescribing multiple medications, as these may contribute to iatrogenic fatigue and cognitive problems in MS. Moreover, researchers should account for polypharmacy when conducting studies examining fatigue and cognition in MS.

Effects of cadmium and mycorrhizal fungi on growth, fitness, and cadmium accumulation in flax (Linum usitatissimum; Linaceae).

PREMISE OF THE STUDY: Agricultural soils have become contaminated with a variety of heavy metals, including cadmium. The degree to which soil contaminants affect plants may depend on symbiotic relationships between plant roots and soil microorganisms. We examined (1) whether mycorrhizal fungi counteract the potentially negative effects of cadmium on the growth and fitness of flax (Linum usitatissimum) and (2) whether mycorrhizal fungi affect the accumulation of cadmium within plant parts. METHODS: Two flax cultivars (Linott and Omega) were grown in three soil cadmium environments (0, 5, and 15 ppm). Within each cadmium environment, plants were grown in either the presence or absence of mycorrhizal fungi. Upon senescence, we measured growth and fitness and quantified the concentration of cadmium within plants. KEY RESULTS: Soil cadmium significantly decreased plant fitness, but did not affect plant growth. Mycorrhizal fungi, which were able to colonize roots of plants growing in all cadmium levels, significantly increased plant growth and fitness. Although mycorrhizal fungi counteracted the negative effects of cadmium on fruit and seed production, they also enhanced the concentration of cadmium within roots, fruits, and seeds. CONCLUSIONS: The degree to which soil cadmium affects plant fitness and the accumulation of cadmium within plants depended on the ability of plants to form symbiotic relationships with mycorrhizal fungi. The use of mycorrhizal fungi in contaminated agricultural soils may offset the negative effects of metals on the quantity of seeds produced, but exacerbate the accumulation of these metals in our food supply.