Thymic Involution in Aging Prospects for Correction

Hadden, John W.; Malec, P; Coto, Jorge A.; Hadden, Elba M.

doi:10.1111/j.1749-6632.1992.tb27458.x

Cited by 33 publications

(11 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Parallel with this, the production of self-hormones (thymulin, thymosin, thymopoietin, and THF) decreases and this could have an important role in the reduction of the lymphatic part. However, extrathymic actions of these hormones are also decreased, less participating in the complex endocrine regulation [154].…”

Section: Discussionmentioning

confidence: 99%

The Immunoendocrine Thymus as a Pacemaker of Lifespan

Csaba¹

2016

Acta Microbiologica et Immunologica Hungarica

View full text Add to dashboard Cite

The thymus develops from an endocrine area of the foregut, and retains the ancient potencies of this region. However, later it is populated by bone marrow originated lymphatic elements and forms a combined organ, which is a central part of the immune system as well as an influential element of the endocrine orchestra. Thymus produces self-hormones (thymulin, thymosin, thymopentin, and thymus humoral factor), which are participating in the regulation of immune cell transformation and selection, and also synthesizes hormones similar to that of the other endocrine glands such as melatonin, neuropeptides, and insulin, which are transported by the immune cells to the sites of requests (packed transport). Thymic (epithelial and immune) cells also have receptors for hormones which regulate them. This combined organ, which is continuously changing from birth to senescence seems to be a pacemaker of life. This function is basically regulated by the selection of self-responsive thymocytes as their complete destruction helps the development (up to puberty) and their gradual release in case of weakened control (after puberty) causes the erosion of cells and intercellular material, named aging. This means that during aging, self-destructive and non-protective immune activities are manifested under the guidance of the involuting thymus, causing the continuous irritation of cells and organs. Possibly the pineal body is the main regulator of the pacemaker, the neonatal removal of which results in atrophy of thymus and wasting disease and its later corrosion causes the insufficiency of thymus. The co-involution of pineal and thymus could determine the aging and the time of death without external intervention; however, external factors can negatively influence both of them.

show abstract

Section: Discussionmentioning

confidence: 99%

The Immunoendocrine Thymus as a Pacemaker of Lifespan

Csaba¹

2016

Acta Microbiologica et Immunologica Hungarica

View full text Add to dashboard Cite

show abstract

“…Given the importance of immune function throughout life, this pattern of early expansion and subsequent regression has puzzled developmentalists and immunologists. The thymus in particular (labeled the "master gland" of the immune system for its critical role in T-cell development and function; Cotman et al, 1987) was identified by a number of investigators as a potential target for intervention in the aging process (Fabris et al, 1988;Hadden et al, 1993). Others suggested that regression protects against autoimmune reactivity later in life (Aronson, 1991), and minimizes energetic costs associated with this relatively expensive tissue (George and Ritter, 1996).…”

Section: Childhoodmentioning

confidence: 99%

Life history theory and the immune system: Steps toward a human ecological immunology

McDade¹

2003

Am. J. Phys. Anthropol.

284

305

View full text Add to dashboard Cite

KEY WORDSimmunology; human biology; growth and development; evolutionary theory; infectious disease ABSTRACTWithin anthropology and human biology, there is growing interest in immune function and its importance to the ecology of human health and development. Biomedical research currently dominates our understanding of immunology, and this paper seeks to highlight the potential contribution of a population-based, ecological approach to the study of human immune function. Concepts from life-history theory are applied to highlight the major challenges and demands that are likely to shape immune function in a range of ecological contexts. Immune function is a major component of maintenance effort, and since resources are limited, trade-offs are expected between investment in maintenance and other critical life-history functions involving growth and reproduction. An adaptationist, life-history perspective helps make sense of the unusual developmental trajectory of immune tissues, and emphasizes that this complex system is designed to incorporate information from the surrounding ecology to guide its development. As a result, there is substantial population variation in immune development and function that is not considered by current biomedical approaches. In an attempt to construct a framework for understanding this variation, immune development is considered in relation to the competing life-history demands that define gestation, infancy, childhood, adolescence, and adulthood. Each life stage poses a unique set of adaptive challenges, and a series of hypotheses is proposed regarding their implications for immune development and function. Research in human ecological immunology is in its earliest stages, but this is a promising area of exploration, and one in which anthropology is wellpositioned to make important contributions. Yrbk Phys Research on human immune function has proliferated in the past 25 years, leading to fundamental insights into basic physiology, as well as strategies for the prevention and treatment of a wide range of diseases. The complexity of the immune system is daunting, and current biomedical research elaborates this complexity by focusing almost exclusively on cellular-and molecular-level processes. The majority of this research uses animal models, with human research participants drawn primarily from clinical settings. Complementary population-based research in international health has observed consistent, bidirectional associations between undernutrition and infectious morbidity, sparking interest in immunocompetence as a potentially important mediator (Chandra, 1988;Gershwin et al., 2000;Hoffman-Goetz, 1986;Pelletier et al., 1995;Suskind and Tontisirin, 2001).The significance of these contributions should not be overlooked, but something is missing. Human physiological systems are products of natural selection, designed to develop and function in whole organisms that are integral components of surrounding social and physical environments (Oyama, 1985;Williams and Nesse, 1991). The immune s...

show abstract

“…The regression in the size, weight, and cellularity of the thymus is known as thymic involution (1)(2)(3)(4). Age-related thymic involution is considered an important factor in immune senescence (5)(6)(7).…”

mentioning

confidence: 99%

IL-12 Inhibits Thymic Involution by Enhancing IL-7- and IL-2-Induced Thymocyte Proliferation

Hsu

Stockard³

et al. 2004

The Journal of Immunology

View full text Add to dashboard Cite

IL-12 has been reported to affect thymic T cell selection, but the role of IL-12 in thymic involution has not been studied. We found that in vivo, IL-12b knockout (IL-12b−/−) mice exhibited accelerated thymic involution compared with wild-type (WT) B6 mice. This is characterized by an increase in thymocytes with the early development stage phenotype of CD25−CD44+CD4−CD8− in aged IL-12b−/− mice. Histologically, there were accelerated degeneration of thymic extracellular matrix and blood vessels, a significantly decreased thymic cortex/medulla ratio, and increased apoptotic cells in aged IL-12b−/− mice compared with WT mice. There was, however, no apparent defect in thymic structure and thymocyte development in young IL-12−/− mice. These results suggest the importance of IL-12 in maintaining thymic integrity and function during the aging process. Surprisingly, in WT B6 mice, there was no age-related decrease in the levels of IL-12 produced from thymic dendritic cells. Stimulation of thymocytes with IL-12 alone also did not enhance the thymocyte proliferative response in vitro. IL-12, however, provided a strong synergistic effect to augment the IL-7 or IL-2 induced thymocyte proliferative response, especially in aged WT and IL-12b−/− mice. Our data strongly support the role of IL-12 as an enhancement cytokine, which acts through its interactions with other cytokines to maintain thymic T cell function and development during aging.

show abstract

Thymic Involution in Aging Prospects for Correction

Cited by 33 publications

References 25 publications

The Immunoendocrine Thymus as a Pacemaker of Lifespan

The Immunoendocrine Thymus as a Pacemaker of Lifespan

Life history theory and the immune system: Steps toward a human ecological immunology

IL-12 Inhibits Thymic Involution by Enhancing IL-7- and IL-2-Induced Thymocyte Proliferation

Contact Info

Product

Resources

About