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Beta-adrenoceptor blockade alters thymocyte differentiation in aged mice
1Department of Neurobiology and Anatomy and the Center for Psychoneuroimmunology Research, University of Rochester School of Medicine and Dentistry, New York, USA. Kelley_Madden@urmc.rochester.edu
Cellular and Molecular Biology (Noisy-Le-Grand, France)
|April 9, 2001
Summary
Norepinephrine signaling via beta-adrenergic receptors impacts thymocyte maturation in aging mice. Blocking these receptors increased naive T-cell output, suggesting a way to improve immune function in older individuals.
Area of Science:
- Immunology
- Neuroendocrinology
- Aging Research
Background:
- The thymus, crucial for naive T-lymphocyte generation, involutes with age, reducing T-cell output.
- Aging is associated with increased sympathetic noradrenergic (NA) innervation and norepinephrine (NE) in the thymus.
Purpose of the Study:
- To investigate if NE signaling through beta-adrenergic receptors modifies age-related changes in thymocyte differentiation and naive T-cell output.
Main Methods:
- BALB/c mice (2-month and 18-month old) received nadolol (a beta-adrenoceptor antagonist) via subcutaneous pellets.
- Thymocyte differentiation and naive T-cell output were assessed using flow cytometry after 4.5 weeks.
Main Results:
- In old mice, beta-adrenoceptor blockade altered thymocyte CD4/CD8 co-expression, increasing immature CD4-8- and mature CD4-8+ populations while reducing intermediate CD4+8+ cells.
- Peripheral blood showed an increased percentage of naive CD8+44low cells in treated old mice, indicating enhanced T-cell export from the thymus.
Conclusions:
- Age-associated sympathetic innervation of the thymus modulates thymocyte maturation.
- Targeting noradrenergic innervation offers a potential strategy to boost naive T-cell output and enhance immune responses in aging individuals.