Image analysis of dermal collagen changes during skin aging

Area of Science:

• Dermatology
• Biomedical Engineering
• Histology

Background:

• Dermal collagen undergoes age-related changes impacting skin biomechanics.
• Understanding these changes is crucial for addressing age-associated skin conditions.

Purpose of the Study:

• To quantitatively assess age and sex-related changes in dermal collagen's structure.
• To model the evolutionary trends of collagen's spatial density, directionality, and texture.

Main Methods:

• Analysis of 96 abdominal skin samples from autopsy cases (3.5 months to 86 years).
• Picro-Sirius staining and polarizing microscopy.
• Computerized image analysis for collagen spatial density, directionality, and texture.
• Nonlinear and linear regression models for age-related trends.

Main Results:

• Dermal thickness and collagen spatial density follow a polynomial trend, increasing until middle age and decreasing thereafter.
• Collagen texture exhibits an inverted U-shaped evolution, with peak complexity in infancy, decreasing until 25-50 years, and increasing post-60 years.
• Collagen bundle orientation simplifies with age, becoming predominantly horizontal in the elderly, following a linear trend.
• No significant sex-based differences were observed.

Conclusions:

• Age-related dermal collagen changes are sex-independent and characterized by curvilinear trends.
• Elderly skin shows decreased thickness and collagen density, with increased textural heterogeneity.
• Progressive simplification and horizontal alignment of collagen bundles contribute to age-related skin biomechanical alterations.