Psychoneuroendocrine interventions aimed at attenuating immunosenescence: a review

Abstract

There is evidence suggesting that immunosenescence can be accelerated by external factors such as chronic stress. Here we review potential psychoneuroendocrine determinants of premature aging of the immune system and discuss available interventions aimed at attenuating immunosenescence. Chronic stress may accelerate various features of immunosenescence by activating key allostatic systems, notably the hypothalamic-pituitary-adrenal axis. The immunological impact of such neuroendocrine dysregulation may be further amplified by a dramatic decline in dehydroepiandrosterone (DHEA) levels, acting in part as an endogenous glucocorticoid antagonist. Stress-buffering strategies show beneficial effects on various biomarkers in elderly populations. Likewise, supplementation of DHEA, melatonin or growth hormone has yielded significant beneficial effects in a number of studies, including: increased well-being, memory performance, bone mineral density and improved immunocompetence as evidenced by results of in vitro (T cell proliferation, cytotoxicity, cytokine production), and in vivo immune challenges. However, the side-effects of hormonal supplementation are also discussed. Finally, moderate exercise via the promotion of cortisol/DHEA balance or epigenetic modifications, is associated with lower serum pro-inflammatory cytokines, greater lymphoproliferative responses and lower counts of senescent T cells. Taken together, these data suggest that immune system is plastic and immunosenescence can be attenuated psychoneuroendocrine interventions.

The role of melatonin in the cells of the innate immunity: a review

“…In a similar manner, the levels of pineal and circulating melatonin decrease with age , and this phenomenon obviously coincides with the age‐related decline of immune function. This fact and the antioxidant and immuno‐enhancing properties of melatonin are the basis for suggesting a potential application of melatonin as a ‘replacement therapy’ to limit or reverse age‐related immunosenescence . The functional competence of NK cells also decreases with advancing age , and in this condition, melatonin stimulates both the production of NK cells and the release of various cytokines from these cells .…”

Neuroendocrine and viral correlates of premature immunosenescence

“…The immune system is plastic and thus can be modified during aging. It may be possible to attenuate and potentially reverse many features of immunosenescence via stress‐management therapies, improved health‐related behaviors, and hormone‐replacement therapies . Furthermore, low‐cost practices, including moderate regular exercise and micronutrient and antioxidant supplementation, may also be beneficial for aging healthily by attenuating the effects of immunosenescence .…”

Annual Research Review: The neuroinflammation hypothesis for stress and psychopathology in children – developmental psychoneuroimmunology

“…These changes are accompanied by elevated levels of the pro-inflammatory cytokines IL-6 and TNF-α, referred to as “inflammaging”(Kollmann, et al, 2012). Additionally, later adulthood is notable for the process of immune-senescence characterized by the accumulation of terminally differentiated memory T cells combined with a paucity of naïve T cells able to respond to new threats (Bauer et al, 2013). There is also a relative shift from Type 1 to Type 2 responses and diminished cell mediated immunity (Bauer, et al, 2013).…”

“…Additionally, later adulthood is notable for the process of immune-senescence characterized by the accumulation of terminally differentiated memory T cells combined with a paucity of naïve T cells able to respond to new threats (Bauer et al, 2013). There is also a relative shift from Type 1 to Type 2 responses and diminished cell mediated immunity (Bauer, et al, 2013). Immuno-senescence markers are linked with normal aging and it has been suggested that this process may be hastened in stress-exposed individuals.…”