Age-Related Changes in the Morphology of Tanycytes in the Human Female Infundibular Nucleus/Median Eminence

Abstract

Tanycytes have been emerging as key players in the neuroendocrine control of gonadotropin-releasing hormone (GnRH) release. Rodent studies have demonstrated that the structural relationship between tanycytes and GnRH terminals in the median eminence is highly dynamic, regulated by gonadal steroids and undergoes age-related changes. Our objective was to determine whether the number and organization of tanycytes changes throughout life in the female infundibular nucleus/median eminence (INF/ME) region. Post-mortem hypothalamic tissues were collected at the Netherlands Brain Bank and were stained for vimentin by immunohistochemistry. Hypothalami of 22 control female subjects were categorized into 3 periods: infant/prepubertal, adult and elderly periods. We measured the fractional area covered by vimentin immunoreactivity in the INF. Qualitative analysis demonstrated a remarkable parallel organization of vimentin-immunoreactive processes at the infant/prepubertal and adult periods. At the elderly period, this organization was largely lost. Semi-quantitatively, the fractional area covered in vimentin immunoreactivity was significantly higher at the infant/prepubertal compared to the adult period and almost reached statistical significance compared to the elderly period. By contrast, the number of tanycyte cell bodies did not seem to change throughout life. Our results thus demonstrate that the number and structure of tanycytic processes are altered during aging, and suggest that tanycytes might be involved in the age-related changes observed in GnRH release.

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