Thymocytopoiesis in aging: the bone marrow-thymus axis
1Department of Immunology, Weizmann Institute of Science, Rehovot, Israel 76100. lcglober@weizmann.weizmann.ac.il
Archives of Gerontology and Geriatrics
|March 1, 1997
Summary
Aging impacts T lymphocyte generation through both thymus and bone marrow (BM) changes. Studies show BM cells exhibit age-related alterations affecting thymocyte development and T cell production.
Area of Science:
- Immunology
- Developmental Biology
- Gerontology
Background:
- T lymphocyte aging is often linked to thymus involution.
- However, aging effects on hematopoietic stem cells (HSCs) and the bone marrow (BM)-thymus axis may also influence T cell generation.
- This study investigates age-related changes originating in the BM.
Purpose of the Study:
- To determine if aging bone marrow (BM) cells exhibit age-related effects impacting thymocyte development.
- To differentiate between aging processes within the BM and those caused by the thymic microenvironment.
- To explore the role of mature T cells in regulating early thymocytopoiesis and how this changes with age.
Main Methods:
- Bone marrow (BM) cells from young donors were cultured on fetal thymus (FT) explants depleted of lymphocytes.
- Analysis of cell cycle kinetics and developmental transitions of thymocytes.
- Investigated feedback regulation by mature T cells on early thymocytopoiesis.
Main Results:
- BM cells showed altered developmental potential, affecting cell cycle kinetics and early thymocyte differentiation (DN to DP stages).
- Early thymocytopoiesis is regulated by mature T cells, with altered regulatory capacity observed in aged individuals.
- Age-related changes in T cell generation result from dynamic interactions between thymic and extrathymic factors.
Conclusions:
- Aging bone marrow (BM) cells contribute to age-related changes in T lymphocyte generation.
- Altered feedback regulation by mature T cells impacts thymocytopoiesis in aging.
- T cell generation is a complex process influenced by both central (thymus) and peripheral (BM, T cells) aging factors.
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