Chronobiology of the Neuroimmunoendocrine System and Aging

Abstract

The health maintenance depends on the preservation of the homeostatic systems, such as nervous, endocrine and immune system, and a proper communication between them. In this regard, the circadian system, which promotes a better physiological system functions and thus well being, could be considered part of that homeostatic complex, since the neuroimmunoendocrine system possesses circadian patterns in most variables, as well as circannual or seasonal variations. With aging, an impairment of the homeostatic systems occurs and an alteration of circadian system regulation has been demonstrated. In the immune system, several function parameters, which are good markers of health and of the rate of aging, change not only with age (immunosenescence) but also throughout the day and year. Indeed, with advancing age there is a modification of immune cell circadian function especially in lymphocytes. Moreover, immune functions at early afternoon correspond to more aged values than at morning, especially in mature subjects (60-79 years of age). In addition, these mature men and women showed a significant impaired immune cell function, which is especially remarkable in the winter. It is noteworthy the role of immunomodulatory hormones, such as melatonin, in the regulation of biological rhythms and their involvement in the aging process. Furthermore, the evidence of a neuroimmune regulation of the circadian system and its disturbance with aging, highlights the importance of proinflammatory cytokines in this complex cross-talk. The biological rhythms disruption with age and some diseases (jet lag, cancer and seasonal affective disorder), could contribute increasing the immune system impairment and consequently the loss of health.

Neuroprotective effect of acute melatonin treatment on hippocampal neurons against irradiation by inhibition of caspase-3

“…As previous studies have demonstrated, Mel acts as a stimulant under immunosuppressive conditions or as an anti-inflammatory compound during immune responses, including acute inflammation (38)(39)(40)(41). Advantageously, Mel is ubiquitously distributed in all the cellular compartments, and is capable of quickly passing through all the biological membranes (42).…”

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

“…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. According to our data, the thymic endocrine function in thymulin production is the important part of chronobiological organization of immune system [19,27].…”

“…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].…”

Evaluation of the Effect of Time Change in Cognitive Function in Volunteers in Tehran

“…The studies in this area indicate that time change can cause the disturbance of the balance between genes, proteins, the activity of endocrine glands and eventually brain's cognitive activities such as memory and learning (Mate et al, 2014; W. E. Bunney & B. G. Bunneym, 2000;Wyatt et al, 1999). For different reasons such as economical motives and others, changes in working hours are carried out by many countries (Rutenfranz et al, 1977).…”

“…Besides that, these changes will lead to changes in circadian rhythm activities of neuron systems and glands and this in return will cause stress in people (Lucas et al, 2012). This stress is considered as a chronic stress in people who have to travel long distances with ultra sound airplanes or the people who have to do shift work and it may led to different changes in the brain activity (Mate et al, 2014). Various studies have shown that chronic stress stimulates the hypothalamus-pituitary-adrenal axis (HPA) and increase the cortisol concentration in the blood continuously and chronically (Asalgoo et al, 2015;Bahari et al, 2015;McEwen et al, 1999;Salehi et al, 2015).…”