Immune response during disease and recovery in the elderly

Abstract

The present article reviews immune ageing and its relationship with nutritional ageing, with a particular insight into the influences of disease on both ageing processes. Immune ageing can be described primarily as the progressive appearance of immune dysregulations, mainly acquired immunity (mature: immature, naive: memory T lymphocyte subset decreases) leading to gradual increases in T-helper 2: T-helper 1 cells. This change is due initially to decreased thymic function, and later to accumulative antigen pressure over the lifespan. In contrast, innate immunity (macrophage functions) is preserved during the ageing process and in the elderly this leads to macrophage-lymphocyte dysequilibrium, which is particularly critical during on-going disease. Indeed, any disease induces long-lasting acute-phase reactions in aged patients and leads to body nutritional reserve (mainly protein) losses. Episodes of disease in the aged patient progressively deplete body nutritional reserves and lead to proteinenergy malnutrition, undernutritionassociated immunodeficiency, and finally cachexia. Undernutrition is a common symptom in the elderly; proteinenergy malnutrition is found in more than 50 % of hospitalized elderly patients and in most elderly diseased subjects. In addition, micronutrient deficit or low levels are common in home-living self-sufficient apparently-healthy elderly subjects. All these nutritional deficits induce decreased immune responses, and micronutrient deficits are now thought to be partly responsible for the decreased immune responses (immune ageing?) observed in the apparentlyhealthy elderly. Indeed, several studies have shown that micronutrient supplements induce increased immune responses in the healthy elderly. The progression of infectious diseases depends on immune responses and on nutritional status before the onset of illness in aged subjects. In addition, recovery depends on the intensity of acute-phase responses in the undernourished elderly. In fact, chronic acute-phase responses, commonly associated with diseases in aged patients, lead to progressive lowering of metabolic responses in the undernourished elderly. This can be quantified by increased production of free radicals during treatment and these increases may explain the difficulty in successfully treating aged patients. Nutritive therapy in order to improve metabolic processes and also to maintain body reserves should be considered as a necessary adjuvant therapy in the treatment of elderly patients. Immune response: Disease: Ageing: ElderlyOne of the most important changes for man in the 20th century is a drastic increase in life expectancy. Life expectancy has almost doubled in the last 100 years (Haut ComitC de la SantC Publique, 1994). As a consequence, the elderly population is rapidly increasing. In France, the elderly population (>60 years) has grown from 10 9% in 1960 to 17 % in 1992, and will continue to increase to comprise onethird of the population by 2030 (Institut National de la Statistique et des Etudes Epidemiologiques, ...

O efeito do índice de massa corporal sobre as complicações no pós-operatório de cirurgia de revascularização do miocárdio em idosos

“…Although the findings do not have statistical significance, it is known that malnutrition in the elderly is associated with increased mortality, as well as susceptibility to infections and reduced quality of life [23]. Malnourishment can impair an elderly patient's ability to manage stress, especially if they are suffering from organ complications or other serious diseases, which results in a higher rate of postoperative complications [24][25].…”

Physiology of aging with respect to gastrointestinal, circulatory and immune system changes and their significance for energy and protein metabolism

“…Tuberculosis is more common. Mortality is greater following a Gram negative infection (Lesourd, 1999). Aging is also associated with an increased prevalence of cancer, and of auto-antibodies.…”

“…This is associated with a decreased ability of stem cells to undergo clonal proliferation (Hirokawa et al, 1994). This means that aged individuals have a reduced capacity to replace destroyed lymphocytes at ef®cient levels when exposed to new infections (Lesourd, 1999). Lymphocyte numbers decrease with age in peripheral blood but such changes remain of minor importance (10 ± 15%, Lesourd, 1997;Huppert et al, 1998).…”

“…Thymic tissues show an involution early in life, and T-lymphocytes genesis is almost abolished after 60 y of age (Lesourd, 1999). This is associated with a decreased ability of stem cells to undergo clonal proliferation (Hirokawa et al, 1994).…”

“…On balance, this is unlikely to affect protein and energy metabolism, in usual circumstances. Lesourd (1999) has proposed that as T-cell proliferation is decreased, these cells need to be more stimulated by the macrophages. The higher secretion of cytokines by Physiology of aging P Ritz macrophages leads to a higher and long-lasting metabolic response (Cederholm et al, 1997).…”