Age-related aging of the immune system (2)

Between the death of immune cells and the activation of cytokine synthesis

Immuno senescence in aging: between immune cells depletion and cytokines up-regulation Maria Teresa Ventura et al., Clinical and Molecular Allergy, 2017.

Translated by Evgenia Ryabtseva
The beginning of the article is here.
For links, see the original article.

Background of the issue

The results of recent studies indicate that a steady increase in life expectancy for residents of Europe, the USA, Canada, Japan and England will allow many children born in the 2000s to live to the age of 100. In this perspective, the main goal of geriatrics is to analyze risk factors for the development of diseases and conditions that potentially lead to the appearance of functional disorders in older people. In the future, this will prevent the development of disability. In general, the increase in life expectancy should coincide with the expected improvements in health and self-service opportunities in the later stages of life.

Old age is a situation in which a number of factors (molecular, cellular, physiological, immunological and psychosocial) contribute to the development of a scenario of "depletion of reserves", which is an inability to functional adaptations and the accumulation of disorders of the functioning of many organs. This situation goes through a dynamic process balancing between "successful" and pathological aging, which causes the development of a state of vulnerability identified as senility. Undoubtedly, the same factors contribute to both the development of a state of decrepitude and an increased life expectancy, which is estimated as reaching the age of 80.

Many factors contributed to this "stretching", including the reduction of infant mortality, antibiotic therapy, as well as prevention of cardiovascular and metabolic diseases. In addition, especially in developed countries, the improvement of sanitary conditions and the quality of nutrition has played a role. However, if aging is not accompanied by the preservation of health, the costs associated with age-related disability or decrepitude may lead to an excessive increase in public health costs, which will have a negative impact on public well-being in general.

Aging of the immune system

The "aging phenotype", including the aging of the immune system, is the result of an imbalance between inflammatory and anti-inflammatory mechanisms, subsequently leading to the development of a condition described by some authors as "inflamaging". This condition is caused by chronic antigenic stimulation occurring throughout life and oxidative stress, which includes the production of reactive oxygen species and toxic waste products. Both of these factors are capable of modifying the potential of apoptotic lymphocytes.

In fact, the phenomenon of "remodeling" and the upregulation of proinflammatory cytokines (including interleukin-6) are the components most strongly involved in the processes of longevity and the development of diseases associated with physiological aging. Both pro-inflammatory and anti-inflammatory chemokines, as well as other signaling molecules, can spread from already activated cells to adjacent cells, as well as systemically with the help of circulating products and microvesicles (microbubbles). The results of recent studies indicate the possibility of studying the molecular foundations of inflamaging using new approaches from the "-omic" series.

In this sense, the good health of the elderly is the result of not only low activity of pro-inflammatory mechanisms, but also an effective system that provides anti-inflammatory neutralization of antigenic effects throughout life. For this reason, the state of inflamaging is important not only from the point of view of the mechanisms of aging of the immune system, but from the point of view of the problem of longevity. There is scientific evidence that decrepitude is the result of an inflammatory condition associated with excessive production of certain lymphokines, including interleukin-6, known as the "cytokine of geriatrics".

This factor, in combination with hormonal changes, nutrient deficiency, lack of physical activity, can lead to the development of one of the most important components of senility – sarcopenia (muscle degradation), as well as to a decrease in bone mass. In this context, the immune system may play an important role both in the regulation of aging mechanisms and in the development of diseases typical of old age, such as infectious diseases, autoimmune conditions, cancer and neurodegenerative diseases.

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