Objective and Methods: We investigated the effects of several growth f
actors on [H-3]thymidine incorporation and procollagen type I carboxyt
erminal propeptide (P1CP) production, which reflects type I collagen m
etabolism, in keloid and normal fibroblasts. Results: Six fibroblast c
ell strains, derived from keloid or normal skin, exhibited similar gro
wth responses to platelet-derived growth factor, transforming growth f
actor beta(1) (TGF-beta(1)), gamma-interferon (gamma-IFN) and histamin
e. In contrast, keloid fibroblasts showed significantly greater growth
response to epidermal growth factor (EGF) than normal fibroblasts. P1
CP production was 4.4 times higher in 6 strains of keloid fibroblasts
than in 6 controls. Treatment with gamma-IFN (100 U/ml) decreased P1CP
production in both groups; the effect was significantly greater in ke
loid fibroblasts. TGF-beta(1) treatment upregulated P1CP production in
both groups. Treatment with histamine increased P1CP production in ke
loid fibroblasts, although it did not change that in the controls. Con
clusion: EGF and histamine may play some role in the development of ke
loids.