Arsenović-Ranin N, Kosec D, Pilipović I, Bufan B, Stojić-Vukanić Z, Radojević K, Nacka-Aleksić M, Leposavić G. Androgens contribute to age-associated changes in peripheral T-cell homeostasis acting in a thymus-independent way.
Neuroimmunomodulation 2014;
21:161-82. [PMID:
24504059 DOI:
10.1159/000355349]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 08/26/2013] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVE
Considering a causal role of androgens in thymic involution, age-related remodeling of peripheral T-cell compartments in the absence of testicular hormones was evaluated.
METHODS
Rats were orchidectomized (ORX) at the age of 1 month, and T-peripheral blood lymphocytes (PBLs) and splenocytes from young (75-day-old) and aged (24-month-old) rats were examined for differentiation/activation and immunoregulatory marker expression.
RESULTS
In ORX rats, following the initial rise, the counts of CD4+ and CD8+ PBLs diminished with aging. This reflected the decline in thymic export as shown by recent thymic emigrant (RTE) enumeration. Orchidectomy increased the count of both of the major T-splenocyte subsets in young rats, and they (differently from controls) remained stable with aging. The CD4+:CD8+ T-splenocyte ratio in ORX rats shifted towards CD4+ cells compared to age-matched controls. Although in the major T-cell subsets in the blood and spleen from aged ORX rats the numbers of RTEs were comparable to the corresponding values in age-matched controls, the numbers of mature naïve and memory/activated cells substantially differed. Compared with age-matched controls, in aged ORX rats the numbers of CD4+ mature naïve PBLs and splenocytes were reduced, whereas those of CD4+ memory/activated cells (predictive of early mortality) were increased. Additionally, in spleens from aged ORX rats, despite unaltered thymic export, CD4+CD25+FoxP3+ and natural killer T cell counts were greater than in age-matched controls.
CONCLUSION
(i) Age-related decline in thymopoietic efficacy is not dependent on androgen presence, and (ii) androgens are involved in the maintenance of peripheral T-cell (particularly CD4+ cell) homeostasis during aging.
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