Growth factor responsiveness declines during adulthood for human skin-derived cells

Area of Science:

• Dermatology
• Cell Biology
• Aging Research

Background:

• Cellular aging is characterized by decreased proliferative capacity.
• Understanding age-related changes in skin cell function is crucial for regenerative medicine and age-related skin conditions.

Purpose of the Study:

• To investigate the impact of aging on keratinocyte and fibroblast proliferation and growth factor responsiveness.
• To determine if reduced growth factor signaling contributes to age-associated decline in skin cell function.

Main Methods:

• Cultured keratinocytes and fibroblasts from young and old adult donors.
• Assessed cell proliferation in response to epidermal growth factor (EGF), keratinocyte growth factor (KGF), and insulin.
• Evaluated the effect of conditioned media from different age groups on keratinocyte growth.

Main Results:

• Keratinocyte growth significantly decreased with age, with reduced responsiveness to KGF and EGF in older adults.
• Fibroblast proliferation also showed age-dependent decline and diminished response to EGF and insulin.
• Newborn keratinocytes responded to newborn conditioned media but not to media from adult donors, indicating age-related changes in secreted factors.

Conclusions:

• A measurable decrease in skin cell proliferative capacity occurs within adulthood.
• Reduced ability to synthesize or respond to mitogens, including autocrine factors, likely underlies age-associated decline in skin cell function.
• These findings highlight the importance of age-related changes in cellular signaling pathways for skin aging.