43
views
0
recommends
+1 Recommend
0 collections
    12
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Could androgens maintain specific domains of mental health in aging men by preserving hippocampal neurogenesis?☆

      review-article
      Neural Regeneration Research
      Medknow Publications & Media Pvt Ltd
      androgen, hippocampus, neurogenesis, aging, cognition, male, testosterone

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Interest surrounds the role of sex-hormones in regulating brain function outside of reproductive behaviour. Declining androgen production in aging males has been associated with cognitive impairment, depression and increased risk of developing Alzheimer's disease. Indication for testosterone replacement therapy is based on biochemically determined low circulating testosterone combined with manifest symptoms. However, which aspects of age-related cognitive decline are attributable to low circulating testosterone remain ambiguous. Studies examining cognition in aging men receiving testosterone replacement therapy have yielded equivocal results. The exact role of testosterone in maintaining cognitive function and the underlying neural mechanisms are largely unknown, though it would appear to be domain specific. Clarity in this area will provide clinical direction toward addressing an increasing healthcare burden of mental health decline coincident with increasing longevity. The premise that androgens contribute to maintaining aspects of mental health in aging men by preserving hippocampal neurogenesis will be used as a forum in this review to discuss current knowledge and the need for further studies to better define testosterone replacement strategies for aging male health.

          Related collections

          Most cited references146

          • Record: found
          • Abstract: found
          • Article: not found

          Pattern separation in the dentate gyrus and CA3 of the hippocampus.

          Theoretical models have long pointed to the dentate gyrus as a possible source of neuronal pattern separation. In agreement with predictions from these models, we show that minimal changes in the shape of the environment in which rats are exploring can substantially alter correlated activity patterns among place-modulated granule cells in the dentate gyrus. When the environments are made more different, new cell populations are recruited in CA3 but not in the dentate gyrus. These results imply a dual mechanism for pattern separation in which signals from the entorhinal cortex can be decorrelated both by changes in coincidence patterns in the dentate gyrus and by recruitment of nonoverlapping cell assemblies in CA3.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Milestones of neuronal development in the adult hippocampus.

            Adult hippocampal neurogenesis originates from precursor cells in the adult dentate gyrus and results in new granule cell neurons. We propose a model of the development that takes place between these two fixed points and identify several developmental milestones. From a presumably bipotent radial-glia-like stem cell (type-1 cell) with astrocytic properties, development progresses over at least two stages of amplifying lineage-determined progenitor cells (type-2 and type-3 cells) to early postmitotic and to mature neurons. The selection process, during which new neurons are recruited into function, and other regulatory influences differentially affect the different stages of development.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Age trends in the level of serum testosterone and other hormones in middle-aged men: longitudinal results from the Massachusetts male aging study.

              We used longitudinal data from the Massachusetts Male Aging Study, a large population-based random-sample cohort of men aged 40-70 yr at baseline, to establish normative age trends for serum level of T and related hormones in middle-aged men and to test whether general health status affected the age trends. Of 1,709 men enrolled in 1987-1989, 1,156 were followed up 7-10 yr afterward. By repeated-measures statistical analysis, we estimated simultaneously the cross-sectional age trend of each hormone between subjects within the baseline data, the cross-sectional trend between subjects within the follow-up data, and the longitudinal trend within subjects between baseline and follow-up. Total T declined cross-sectionally at 0.8%/yr of age within the follow-up data, whereas both free and albumin-bound T declined at about 2%/yr, all significantly more steeply than within the baseline data. Sex hormone-binding globulin increased cross-sectionally at 1.6%/yr in the follow-up data, similarly to baseline. The longitudinal decline within subjects between baseline and follow-up was considerably steeper than the cross-sectional trend within measurement times for total T (1.6%/yr) and bioavailable T (2-3%/yr). Dehydroepiandrosterone, dehydroepiandrosterone sulfate, cortisol, and estrone showed significant longitudinal declines, whereas dihydrotestosterone, pituitary gonadotropins, and PRL rose longitudinally. Apparent good health, defined as absence of chronic illness, prescription medication, obesity, or excessive drinking, added 10-15% to the level of several androgens and attenuated the cross-sectional trends in T and LH but did not otherwise affect longitudinal or cross-sectional trends. The paradoxical finding that longitudinal age trends were steeper than cross-sectional trends suggests that incident poor health may accelerate the age-related decline in androgen levels.
                Bookmark

                Author and article information

                Journal
                Neural Regen Res
                Neural Regen Res
                NRR
                Neural Regeneration Research
                Medknow Publications & Media Pvt Ltd (India )
                1673-5374
                1876-7958
                05 October 2012
                : 7
                : 28
                : 2227-2239
                Affiliations
                [1] Florey Neurosciences Institute, Melbourne Brain Centre, the University of Melbourne, Parkville, Victoria 3010, Australia
                Author notes
                [☆]

                Mark I Ransome, NHMRC Australian Postdoctoral Fellow, Ph.D., Florey Neuroscience Institutes, Melbourne Brain Centre, the University of Melbourne, Parkville, Victoria 3010, Australia

                Corresponding author: Mark I Ransome, Florey Neuroscience Institutes, Melbourne Brain Centre, the University of Melbourne, Parkville 3010, Victoria, Australia mark.ransome@ 123456florey.edu.au . (NY20120524001/ZLJ)

                Author contributions: Mark I Ransome conceived, drafted and wrote the final version including figure preparation entirely.

                Article
                NRR-7-2227
                10.3969/j.issn.1673-5374.2012.028.009
                4268723
                f1ade1dd-cd9f-4652-9129-85f45068b4cd
                Copyright: © Neural Regeneration Research

                This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

                History
                : 25 May 2012
                : 10 July 2012
                Categories
                Review

                androgen,hippocampus,neurogenesis,aging,cognition,male,testosterone
                androgen, hippocampus, neurogenesis, aging, cognition, male, testosterone

                Comments

                Comment on this article