A study of individual behaviour in age-related decline in the pineal secretion of melatonin: possible implications in the prevention of age-related human diseases

According to the recent advances in the psychoneuroendocrinoimmune (PNEI) regulation of the human biology,1 the old age has appeared to be a reversible phenomenon by acting on the same mechanisms responsible for age-related progressive decline in the biological functions.2 At present, it is known that the old age is mainly characterized by a progressive decline in the regulation of the biological rhythms, an enhanced free-radical production and a progressive increase in fibrosis processes involving the different organs of the human body, mainly the vascular system.3 Several hypotheses have been proposed to explain age-related processes, including a reduced telomere length, and free radical-induced DNA damage. Moreover, it has to be remarked that one of the most important regulator of the biological life is represented by the immune system, since it has been demonstrated that it is involved not only in host defences, but also in the control of several biological functions, including the endocrine secretions and the cardiovascular function.4 Therefore, the progressive decline in the immune functionless, mainly in its capacity of balance between stimulatory and immunosuppressive events, could play an essential role in aging processes.5 In addition, since the pineal gland plays an essential role in the regulation of the biological rhythms and free-radical production,6 age-related processes would mainly depend on the functionless of the pineal gland, whose most investigated hormone is the in dole hormone melatonin (MLT).7 MLT secretion has been proven to be characterized by a well defined light/dark circadian rhythm, with low levels during the light phase of the day and highest concentrations during the night period of the day.8