Differential effects of photoaging vs intrinsic aging on the vascularization of human skin

Objective: To quantify the distinct effects of photoaging vs; intrinsic aging of human skin on cutaneous vascularization in the Korean population. Design: Case series. Setting: University hospital. Participants: A total of 21 healthy Korean volunteers from the third to the ninth decades of life. Intervention: Skin biopsy specimens were obtained from chronically sun-exposed and sun-protected skin of each participant. Main Outcome Measures: Frozen sections were stained for the platelet endothelial cell adhesion molecule CD31 (PECAM-1), and computer-assisted quantitative image analysis was performed to quantify cutaneous vascular density and vessel size. Results: Intrinsically aged and photoaged skin showed an age-dependent reduction of cutaneous vessel size. However, only photoaged skin exhibited significantly reduced numbers of dermal vessels, in particular in the subepidermal areas that displayed extensive matrix damage. Linear regression analysis revealed an inverse relation of vessel numbers and age in sun-damaged, but not in sun-protected, skin. Conclusions: In Korean skin, chronic photodamage results in a gradual decrease in the number and size of dermal vessels over several decades of sun exposure, most likely due to degenerative changes of the dermal extracellular matrix. Because the present investigation was restricted to ethnic Korean volunteers, future studies are needed to evaluate whether similar changes can be observed in whites.