Nelson Vergel
Founder, ExcelMale.com
The cortex of the brain is a thick layer of nerve cells on the surface of the brain. The nerve cells in this area are mainly responsible for memory, attention, awareness, thought, language, and consciousness. Testosterone replacement in men with low T may help with some of these factors but no one has looked at the effect of TRT on the cortex.
Effects of Testosterone Supplementation and Serum Levels on Cortical Volume in Healthy Older Men
Neurology April 6, 2015 vol. 84 no. 14 Supplement P7.103
OBJECTIVE: The aim of this study is to evaluate neuroanatomical transformations after testosterone (T) supplementation via Voxel-Based Morphometry (VBM), an imaging technique used to measure regional cortical changes in MRI scans following global brain shape normalization.
BACKGROUND: Men with low levels of endogenous T have been shown to have mild impairments in memory, executive function, visuospatial abilities, and verbal fluency. Recent work has suggested that exogenous T may improve cognitive performance in a curvilinear distribution. We hypothesized that after T-supplementation in men with low-normal T levels, cortical volumes in the hippocampus, prefrontal cortex (Brodmann area 10), and the temporal-occipital-parietal junction will change in a dose-dependent, curvilinear manner.
DESIGN/METHODS: 32 healthy older men (mean: 64.0, range: 60-82 yrs) with low-normal T levels (200-350 ng/dl) were randomized into one of three intervention T supplementation groups: 1) none (placebo), 2) low-dose (25 mg/day), and 3) usual/higher-dose (50 mg/day). Subjects had MRI brain scans pre- and 10-12 months post-T-supplementation. We performed VBM analysis to determine changes in total cortical volume and changes in prior regions of interest (as noted) volumes pre- versus post-T-supplementation for all subjects. Group differences were evaluated with one-way ANOVA and regression analyses were performed.
RESULTS: No group differences were noted in total and regional cortical volumes using uncorrected voxel-level significance threshold of p<0.001. A curvilinear, inverted U-shaped correlation unrelated to group between final T levels achieved and total cortical volume change after supplementation was noted (p = 0.028 , R^2 = 0.15), such that low and high levels resulted in lower cortical volumes.
CONCLUSIONS: No significant correlation between T- supplementation group and total or regional cortical volumes were noted, but the inverted U-shaped relationship between achieved T level and total cortical volume suggests an optimal level of testosterone may be important.
Comment: Too little and too much testosterone lowered cortical volume. There seems to be an optimal level in between.
Study Supported by: NIH grant T35 EY021455 (Vision Scholars)
Effects of Testosterone Supplementation and Serum Levels on Cortical Volume in Healthy Older Men
Neurology April 6, 2015 vol. 84 no. 14 Supplement P7.103
OBJECTIVE: The aim of this study is to evaluate neuroanatomical transformations after testosterone (T) supplementation via Voxel-Based Morphometry (VBM), an imaging technique used to measure regional cortical changes in MRI scans following global brain shape normalization.
BACKGROUND: Men with low levels of endogenous T have been shown to have mild impairments in memory, executive function, visuospatial abilities, and verbal fluency. Recent work has suggested that exogenous T may improve cognitive performance in a curvilinear distribution. We hypothesized that after T-supplementation in men with low-normal T levels, cortical volumes in the hippocampus, prefrontal cortex (Brodmann area 10), and the temporal-occipital-parietal junction will change in a dose-dependent, curvilinear manner.
DESIGN/METHODS: 32 healthy older men (mean: 64.0, range: 60-82 yrs) with low-normal T levels (200-350 ng/dl) were randomized into one of three intervention T supplementation groups: 1) none (placebo), 2) low-dose (25 mg/day), and 3) usual/higher-dose (50 mg/day). Subjects had MRI brain scans pre- and 10-12 months post-T-supplementation. We performed VBM analysis to determine changes in total cortical volume and changes in prior regions of interest (as noted) volumes pre- versus post-T-supplementation for all subjects. Group differences were evaluated with one-way ANOVA and regression analyses were performed.
RESULTS: No group differences were noted in total and regional cortical volumes using uncorrected voxel-level significance threshold of p<0.001. A curvilinear, inverted U-shaped correlation unrelated to group between final T levels achieved and total cortical volume change after supplementation was noted (p = 0.028 , R^2 = 0.15), such that low and high levels resulted in lower cortical volumes.
CONCLUSIONS: No significant correlation between T- supplementation group and total or regional cortical volumes were noted, but the inverted U-shaped relationship between achieved T level and total cortical volume suggests an optimal level of testosterone may be important.
Comment: Too little and too much testosterone lowered cortical volume. There seems to be an optimal level in between.
Study Supported by: NIH grant T35 EY021455 (Vision Scholars)
