The skin of the eyelid is known to scar relatively lightly. In contrast, skin of other sites (e.g. pre-sternal area) scar vigorously. Little is known about the mechanisms which mediate this difference in behaviour. The aims of their study were to compare measures of eyelid and presternal skin fibroblast contraction induced by stretch and by pro-inflammatory cytokines.

Three Cell lines of pre-sternal and upper eyelid skin were harvested from patients undergoing upper lid blepharoplasty. Cells were seeded in free-floating 3D collagen matrices by a process of rapid polymerisation. Contractile efficiency was assessed by daily serial digital photography of the gel diameter over a 7-day period. Comparisons between Presternal and Blepharoplasty skin was made was made. Matrices were incubated under several conditions: TGF-B and IL-1B, both of which are well recognised as being pro-fibrotic cytokines .Fibroblast populated collagen matrices were subjected to stretch experiments using a Culture Force Monitor (CFM) to detect the minute contractile forces exerted by cells.

Presternal skin fibroblasts were found to have a greater baseline contractility that eyelid fibroblasts in free floating collagen gels. When exposed to external stretch, these cell lines did not differ in their contractile response. Presternal skin fibroblasts increased their contraction in the presence of TGF-B in contrast to eyelid fibroblasts, which did not respond.

Eyelid skin fibroblasts differ in their fibrosis response when compared to presternal skin fibroblasts. Intrinsic differences in cell phenotype and response to inflammatory stimuli, rather than skin tension alone underlie these differences.