Aging affects all organs but is most visible in the skin. The skin can reflect changes in internal organs, such as the correlation between facial wrinkles and lung disease in COPD. Aging is influenced by both genetics and environmental factors

• Epidermal Thinning :

The outer skin layer becomes thinner, especially in deep wrinkles.

• Dermal Changes:

The junction between the dermis and epidermis flattens, and there is atrophy in the subcutaneous fat and loss of collagen, glycosaminoglycans, and elastin

• Collagen Loss

- Collagen production decreases with age, and higher levels of enzymes called matrix metalloproteinases (MMPs) increase collagen breakdown.
- Collagen Glycation: A process where sugar molecules attach to collagen, making it stiff and less able to repair. This results in advanced glycation end products (AGEs), which lead to more collagen
breakdown.

• Elastin Degradation

- Elastic tissue decreases with age, leading to less skin resilience. UV exposure increases elastase, an enzyme that degrades elastin, causing photoaged skin.

• Telomere Shortening

- Telomeres are protective caps on chromosome ends. They shorten with each cell division, leading to cell death when they become too short. This process is linked to aging.

- UV exposure may accelerate telomere shortening by damaging the protective loop structure of telomeres.

• Immune System Changes

- Aging increases proinflammatory cytokines, which cause inflammation and contribute to collagen degradation. The function of immune cells declines with age

• Other Factors

- The endocrine system, including insulin, vitamin D, and thyroid hormones, likely influences skin aging. - Hormones like estrogen and androgens significantly affect skin aging.