What is Inflammaging?
Inflammaging is a term that combines "inflammation" and "aging," referring to the chronic, low-grade inflammation that characterizes aging. Unlike acute inflammation, which is a protective response to injury or infection, inflammaging is a persistent state that contributes to the degeneration of tissues and the development of age-related diseases.
Histological Features of Inflammaging
Histologically, inflammaging is characterized by an accumulation of senescent cells that secrete pro-inflammatory cytokines, chemokines, and other mediators, collectively known as the
senescence-associated secretory phenotype (SASP). These secretions can alter the tissue microenvironment, leading to chronic inflammation. Key histological markers include increased infiltration of immune cells, such as
macrophages and
T lymphocytes, and the presence of senescent cells, identifiable by markers such as
p16INK4a and
β-galactosidase.
Skin: Increased collagen breakdown, reduced elasticity, and higher risk of infections.
Cardiovascular System: Increased arterial stiffness and atherosclerosis due to chronic inflammation.
Musculoskeletal System: Osteoporosis and sarcopenia, which are linked to chronic inflammatory markers.
Nervous System: Neuroinflammation, contributing to conditions like Alzheimer's disease and other neurodegenerative disorders.
Senescent Cells: These cells stop dividing but remain metabolically active, secreting pro-inflammatory factors.
Mitochondrial Dysfunction: Aging mitochondria produce more
reactive oxygen species (ROS), promoting inflammation.
Immune System Dysregulation: Aging affects the immune system, leading to an imbalanced response that favors chronic inflammation.
Epigenetic Changes: Aging-related modifications in DNA methylation and histone acetylation can alter the expression of inflammation-related genes.
Anti-inflammatory Diets: Diets rich in antioxidants and anti-inflammatory foods can reduce chronic inflammation.
Exercise: Regular physical activity has been shown to lower inflammatory markers.
Pharmacological Interventions: Drugs like
metformin and
rapamycin have shown promise in reducing inflammaging.
Senolytics: These are drugs designed to selectively eliminate senescent cells, thereby reducing their pro-inflammatory secretions.
Conclusion
In summary, inflammaging is a significant factor in the aging process, characterized by chronic, low-grade inflammation that affects various tissues. Histologically, it involves the accumulation of senescent cells and increased infiltration of immune cells. Understanding the cellular mechanisms and potential interventions can help in developing strategies to mitigate its impact on health.
