The aging immune system (immunosenescence) has been implicated with increased morbidity and mortality in the elderly. Of note, T cell aging and low-grade inflammation (inflammaging) are implicated with several age-related conditions. The expansion of late-differentiated T cells (CD28 −), regulatory T cells, increased serum levels of autoantibodies, and pro-inflammatory cytokines were implicated with morbidities during aging. Features of accelerated immunosenescence can be identified in adults with chronic inflammatory conditions, such as rheumatoid arthritis, and are predictive of poor clinical outcomes. Therefore, there is an interplay between immunosenescence and age-related diseases. In this review, we discuss how the aging immune system may contribute to the development and clinical course of age-related diseases such as neurodegenerative diseases, rheumatoid arthritis, cancer, cardiovascular, and metabolic diseases.
Prenatal and early postnatal environments can permanently influence health throughout life. Early overnutrition increases the risk to develop chronic diseases. Conversely, the intake of flavonoids and exercise practice during pregnancy seem to promote long-term benefits to offspring. We hypothesized that benefic interventions during pregnancy could protect against possible postnatal neurochemical alterations caused by overnutrition induced by reduced litter size. Female Wistar rats were divided into four groups: (1) sedentary + vehicle, (2) sedentary + naringenin, (3) swimming exercise + vehicle, and (4) swimming exercise + naringenin. One day after birth, the litter was culled to 8 pups (control) or 3 pups (overfed) per dam, yielding control and overfed subgroups for each maternal group. Serum of 21-days-old pups was collected, also the cerebellum, hippocampus, and hypothalamus were dissected. Litter size reduction increased fat mass and enhanced body weight. Maternal interventions, when isolated, caused reduced glucose serum levels in offspring nurtured in control litters. In the cerebellum, reducing the litter size decreased the activity of thioredoxin reductase, which was prevented by maternal supplementation with naringenin. Hippocampus and hypothalamus have shown altered antioxidant enzymes activities in response to litter size reduction. Interestingly, when maternal exercise and naringenin supplementation were allied, the effect disappeared, suggesting a concurrent effect of the two maternal interventions. In conclusion, exercise or naringenin supplementation during pregnancy can be important interventions for combating the increasing rates of overweight during the infancy and its related neurochemical changes, especially when applied isolated.
Aging is associated with an increased incidence of autoimmune diseases, despite the progressive decline of immune responses (immunosenescence). This apparent paradox can be explained by the age-related chronic low-grade systemic inflammation (inflammaging) and progressive dysregulation of innate signaling. During cellular aging, there is an accumulation of damaged DNA in the cell’s cytoplasm, which serves as ubiquitous danger-associated molecule, promptly recognized by DNA sensors. For instance, the free cytoplasmic DNA can be recognized, by DNA-sensing molecules like cGAS-STING (cyclic GMP-AMP synthase linked to a stimulator of interferon genes), triggering transcriptional factors involved in the secretion of pro-inflammatory mediators. However, the contribution of this pathway to the aging immune system remains largely unknown. Here, we highlight recent advances in understanding the biology of the cGAS-STING pathway, its influence on the senescence-associated secretory phenotype (SASP), and its modulation of the immune system during sterile inflammation. We propose that this important stress sensor of DNA damage is also a trigger of immunosenescence and inflammaging.
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