Leigh Murray

Serum brain-derived neurotrophic factor is associated with cognitive function in healthy older adults.

Cognitive decline is common in older adults, even in the absence of significant medical or neurological conditions. Recent work implicates serum levels of brain-derived neurotrophic factor in age-related cognitive decline, though no study has directly examined this possibility. A total of 35 older adults without neurological history underwent fasting blood draw and completed a brief neuropsychological test battery during a single session. After adjusting for demographic and medical confounds, higher serum brain-derived neurotrophic factor levels were associated with better performance on the Mini-Mental State Examination (r = .36) and short form of the Boston Naming Test (r = .39). These findings extend work from Alzheimer disease and vascular dementia samples and indicate that higher brain-derived neurotrophic factor levels are associated with better neuropsychological function in healthy older adults. The exact mechanisms for this relationship are unknown and require further examination.

The Influence of Ethnicity on Thermoregulation After Acute Cold Exposure

Abstract Objective.—It is well established that a combination of factors, including ethnicity, may influence an individuals response to cold stress. Previous work from our laboratory has demonstrated that when faced with a cold challenge, there is a similar response in heat production between Caucasian (CAU) and African American (AA) individuals that is accompanied by a differential response in core temperature. The objective of this study was to evaluate the influence of ethnicity (CAU vs AA) on the thermoregulatory response after acute cold exposure (ACE-REC, 25°C air). Methods.—Five AA males (20.8 ± 0.5 years) and 10 CAU males (25.6±4.9 years) underwent pre-experimental testing to determine Vo2max (AA = 37.2 ± 0.1 mL·kg−1·min−1, CAU = 44.3 ± 8.7 mL·kg−1·min−1) and body composition (AA = 14.6 ± 5.4%, CAU = 19.2 ± 5.0%). Participants underwent acute cold exposure that consisted of 120 minutes of exposure to 10°C air (ACE) followed by 120 minutes of recovery in 25°C air (ACE-REC). Rectal temperature (Tre) was measured via a rectal thermistor. Mean skin temperature (Tsk) was assessed with thermistors. Oxygen consumption (Vo2) was assessed via indirect open circuit spirometry. Rectal temperature and Tsk were measured continuously, and if Tre ≤ 35°C, testing was terminated. Results.—Analysis of variance for ACE-REC revealed a significant main effect for Tsk across time (P < .001), Tre across time (P < .001), and Vo2 across time (P < .001). In addition, a significant time × ethnicity interaction was revealed for Tre (P = .008), Tsk (P = .042), and Vo2 (P = .019) during ACE-REC. Conclusions.—Based on these data, there is a differential response between CAU and AA across time for Vo2, Tre, and Tsk ACE-REC.

Serum brain-derived neurotrophic factor is associated with reduced appetite in healthy older adults.

Objective: Loss of appetite and body mass are common in older adults and are associated with negative consequences. Research indicates that these processes likely involve increases in serum brain-derived neurotrophic factor (BDNF). Animal and human models demonstrate that BDNF may serve a regulatory function in food intake, but no study has addressed the possibility that BDNF may be involved in appetite reduction and loss of body mass in older adults.Design and Participants: 34 older adults without significant neurological or psychiatric history underwent fasting blood draw and measurement of body composition. Appetite and eating behavior were assessed by questionnaire and related to serum BDNF levels.Results: Partial correlations showed serum BDNF levels were inversely related to appetite (r = −.38, p = .02). No significant correlations emerged between serum BDNF and age, diet, or body composition.Conclusions: The current study extends past work and shows that BDNF is associated with appetite in healthy older adults. Further work is needed to clarify mechanisms for these findings, particularly prospective studies.