Does the paucity of elastic fibres contribute to the process of keloidogenesis?

Abstract

Introduction: Keloids are a prototype of excessive wound healing. Keloid fibroblasts generate traction force, which deforms and realigns the collagen network during migration. Cells move bidirectionally along aligned fibres resulting in nonuniform cell distribution. This and the anisotropic collagen properties displayed in keloids, may be governed by traction force. Excessive traction force (>elastic limit), causes permanent deformations. As recovery from deformational forces is attained mainly by elastic recoil, we hypothesised that in keloids the elastic limit is decreased by reduced numbers of dermal elastic fibres, leading to permanent plastic deformation of dermal tissue by traction force.

Objective: To quantitate and compare the elastic fibre content of keloids and non-lesional skin

Methods: Sections of keloids and non-lesional skin from 32 patients were stained with elastic Van Gieson. The elastic fibre content was histomorphometrically quantified and the mean (± SEM) percentage area of elastic fibres in lesional and non-lesional skin was compared.

Results: Elastic fibres at the border of keloids were increased whereas internally they were minimal or absent. Statistical analysis (Wilcoxon signed ranks test) showed significant differences (p < 0.05) in elastic fibre content between non-lesional dermis and keloids.

Conclusions: The lack of elastic fibres in keloids decreases the elastic limit, leading to effects of excessive deformational force. These include compression and stiffening of tissue, increased mitogenesis and cell contractility, modified DNA and protein synthesis and increased collagen biosynthesis. The manifestation of these effects in keloids, supports the hypothesis that decreased elasticity in keloids promotes permanent dermal deformation by traction forces.

Keywords: Elastic fibres; wound healing fibroblasts; deformation forces; histomorphometric analysis.Running title: Comparative histomorphometric analysis of elastic fibres in lesional and non-lesional skin of patients with keloids