Validation of a Dynamic Measure of Current Cognitive Reserve in a Longitudinally Assessed Sample of Healthy Older Adults.

Cognitive reserve (CR) is a theoretical construct describing the underlying cognitive capacity of an individual that confers differential levels of resistance to, and recovery from, brain injuries of various types. To date, estimates of an individual's level of CR have been based on single proxy measures that are retrospective and static in nature. To develop a measure of dynamic change in CR across a lifetime, we previously identified a latent factor, derived from an exploratory factor analysis of a large sample of healthy older adults, as current CR (cCR). In the present study, we examined the longitudinal results of a sample of 272 older adults enrolled in the Tasmanian Healthy Brain Project. Using results from 12-month and 24-month reassessments, we examined the longitudinal validity of the cCR factor using confirmatory factor analyses. The results of these analyses indicate that the cCR factor structure is longitudinally stable. These results, in conjunction with recent results from our group demonstrating dynamic increases in cCR over time in older adults undertaking further education, lend weight to this cCR measure being a valid estimate of dynamic change in CR over time

The chemerin knockout rat reveals chemerin dependence in female, but not male, experimental hypertension

Measures of the adipokine chemerin are elevated in multiple cardiovascular diseases, including hypertension, but little mechanistic work has been done to implicate chemerin as being causative in such diseases. The chemerin knockout (KO) rat was created to test the hypothesis that removal of chemerin would reduce pressure in the normal and hypertensive state. Western analyses confirmed loss of chemerin in the plasma and tissues of the KO vs. wild‐type (WT) rats. Chemerin concentration in plasma and tissues was lower in WT females than in WT males, as determined by Western analysis. Conscious male and female KO rats had modest differences in baseline measures vs. the WT that included systolic, diastolic, mean arterial and pulse pressures, and heart rate, all measured telemetrically. The mineralocorticoid deoxycorticosterone acetate (DOCA) and salt water, combined with uninephrectomy as a hypertensive stimulus, elevated mean and systolic blood pressures of the male KO higher than the male WT. By contrast, all pressures in the female KO were lower than their WT throughout DOCA‐salt treatment. These results revealed an unexpected sex difference in chemerin expression and the ability of chemerin to modify blood pressure in response to a hypertensive challenge.—Watts, S. W., Darios, E. S., Mullick, A. E., Garver, H., Saunders, T. L., Hughes, E. D., Filipiak, W. E., Zeidler, M. G., McMullen, N., Sinal, C. J., Kumar, R. K., Ferland, D. J., Fink, G. D. The chemerin knockout rat reveals chemerin dependence in female, but not male, experimental hypertension. FASEB J. 32, 6596–6614 (2018). www.fasebj.orgPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154357/1/fsb2fj201800479.pd

The BDNF Val66Met Polymorphism Moderates the Effect of Cognitive Reserve on 36-month Cognitive Change in Healthy Older Adults

Introduction: Cognitive reserve (CR) and BDNF Val66Met are independently associated with the rate of cognitive decline in preclinical Alzheimer\u27s disease. This study was designed to investigate the interactive effects of these variables on 36-month cognitive change in cognitively intact older adults. Methods: Data for this investigation were obtained from 445 community-residing participants of the Tasmanian Healthy Brain Project, who underwent genetic screening and annual assessment of neuropsychological, health, and psychosocial function. Results: Our main result was that BDNF Val66Met moderated the relationship between baseline CR and change in executive function performance, in that CR-related differences in function decreased across the follow-up period in BDNF Val homozygotes, but became more pronounced in BDNF Met carriers. Similar effects were not observed within the other memory- and language-related cognitive domains. Discussion: Inheritance of BDNF Met may be associated with a detrimental influence on the relationship between CR and cognitive change in cognitively intact older adults, but this effect may be restricted to the executive function domain