Sub-Clinical Cognitive Decline and Resting Cerebral Blood Flow in Middle Aged Men

Although dementia is associated with both global and regional cerebral blood flow (CBF) changes, little is known about cerebral perfusion in the early pre-clinical stages of cognitive decline preceding overt cognitive dysfunction. The aim of this study was to investigate the association of early sub-clinical cognitive decline with CBF. The study participants were recruited from a cohort of Danish men born in 1953. Based on a regression model we selected men who performed better (Group A, n=94) and poorer (Group B, n=95) on cognitive testing at age 57 than expected from testing at age 20. Participants underwent supplementary cognitive testing, blood sampling and MRI including measurements of regional and global CBF. Regional CBF was lower in group B than in group A in the posterior cingulate gyrus and the precuneus. The associations were attenuated when corrected for global atrophy, but remained significant in regions of interest based analysis adjusting for regional gray matter volume and vascular risk factors. No influence of group on global CBF was observed. We conclude that early sub-clinical cognitive decline is associated with reduced perfusion in the precuneus and posterior cingulate gyrus independently of regional atrophy and vascular risk factors, but cannot be statistically separated from an association with global atrophy

Molecular diversity of the equine caecal microbiota and its correlation to postprandial fermentation metabolites: A preliminary approach

acceptedVersio

High nutrient availability reduces the diversity and stability of the equine caecal microbiota

Background: It is well known that nutrient availability can alter the gut microbiota composition, while the effect on diversity and temporal stability remains largely unknown. Methods: Here we address the equine caecal microbiota temporal stability, diversity, and functionality in response to diets with different levels of nutrient availability. Hay (low and slower nutrient availability) versus a mixture of hay and whole oats (high and more rapid nutrient availability) were used as experimental diets. Results: We found major effects on the microbiota despite that the caecal pH was far from sub-clinical acidosis. We found that the low nutrient availability diet was associated with a higher level of both diversity and temporal stability of the caecal microbiota than the high nutrient availability diet. These observations concur with general ecological theories, suggesting a stabilising effect of biological diversity and that high nutrient availability has a destabilising effect through reduced diversity. Conclusion: Nutrient availability does not only change the composition but also the ecology of the caecal microbiota

Effect of hemoglobin on regional CBF.

<p>Glass brain representation of voxels in absolute CBF maps with significant (p<0.001) negative correlation with blood hemoglobin. Brain volume covered by the ASL measurements is shown in the red box.</p