The Immunoendocrine Thymus as a Pacemaker of Lifespan

Abstract

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.

Age-Related Changes in the Melatonin and Thymulin Biorhythms as Risk Factors for Human Neurodegenerative Diseases

“…As has been described in the review of Csaba [5], the thymus is not only the lymphoid organ. It also serves as the endocrine organ producing the following hormones: thymic serum factor (FTS) or thymulin, thymosine, thymopoetin and thymus humoral factor.…”

“…Csaba [5] stressed that immunoendocrine thymus is a pacemaker of lifespan and its coinvolution with pineal gland can determine the aging. In the opinion of Mate and co-workers [3], impairment of circadian and seasonal fluctuations of immune functions in human aging may be connected with disturbances of melatonin production.…”

“…In aging there occurs dyscoordination of rhythms and disturbance of adaptive capacity of many organism functions, in particular of the neuroendocrine and immune systems [2,3]. Of a special interest is the regulator of biorhythms of the pineal gland hormone, melatonin, and the regulator of immune function of the thymic hormone, thymulin [4,5]. Many investigators have revealed age-related changes in the functions of pineal gland and thymus and their impact on lifespan in humans [6,7].…”

Зміни Ендокринної Функції Тимуса, Макрофагів І Т-Лімфоцитів Головного Мозку В Мишей Різного Віку Після Введення Нейротоксину Купризону І Цитокіну

“…Источником провоспалительных цитокинов также могут быть Т-лимфоциты, инфильтрирующие головной мозг при этих патологиях [2]. Дифференцировка Т-лимфоцитов и активность их субпопуляций находятся под регулирующим влиянием одного из гормонов тимуса -высокоактивного тимулина [3,4]. Антивоспалительный эффект тимулина у животных с экспериментальной моделью повреждения головного мозга связан с угнетением синтеза провоспалительных цитокинов [5].…”

Effect of 1,2-Dimethylhydrazine on Spleen Immunomorpholog

“…The only weapon against carcinogenesis in the body is the immune system, with which the growing tumor has a complex and yet unexplored relationship. This problem is studied by a relatively young scienceoncoimmunology [2]. 1,2-dimethylhydrazine dihydrochloride (DMH) is a derivative of hydrazine, the carcinogenicity of which has been known for more than 40 years.…”