title: Collagen morphology in human skin and scar tissue: no adaptations in response to mechanical loading at joints.
abstract: Dermal collagen displays a random-like structure that has a major role in strength and function of the human integument. It is hypothesised that collagen bundles align in a parallel fashion in the direction of mechanical tension during scarring, which may explain the problematic scar formation that occurs specifically at joints. Scar tissue and normal skin were biopsied from joints and control areas and evaluated by the Fourier analysis. Collagen orientation was represented by an index ranging from 0 (perfectly random) to 1 (perfectly parallel). Collagen bundle packing signifies the average distance between the centres of collagen bundles. No differences were shown in collagen morphology of scar tissue and normal skin between joints and control areas. Normal skin had a significantly lower collagen orientation index than scar tissue (0.26 versus 0.44, P<0.001). The bundle packing of scar tissue differed significantly from normal skin (18.1 microm versus 23.7 microm, P<0.001). Collagen appeared less parallel orientated in deep dermis compared to superficial dermis especially for normal skin (0.27 versus 0.33, P=0.06). Normal skin had a less parallel organisation in sections that were cut parallel compared to those that were cut perpendicular to the epidermis (0.24 versus 0.30, P=0.02). Collagen orientation of scar tissue is more parallel compared to normal skin. Morphology differs with respect to superficial and deep dermal layers and parallel and perpendicular planes, but appears not to respond to mechanical tension.
authors.affiliation: Burn Centre and Department of Surgery, Red Cross Hospital, Vondellaan 13, 1942 LE Beverwijk, The Netherlands. paul.van.zuijlen@planet.nl
authors.forename: Paul P M
authors.initials: PP
authors.lastname: van Zuijlen
authors.forename: Joris J B
authors.initials: JJ
authors.lastname: Ruurda
authors.forename: Henk A
authors.initials: HA
authors.lastname: van Veen
authors.forename: Jan
authors.initials: J
authors.lastname: van Marle
authors.forename: Antoine J M
authors.initials: AJ
authors.lastname: van Trier
authors.forename: Frits
authors.initials: F
authors.lastname: Groenevelt
authors.forename: Robert W
authors.initials: RW
authors.lastname: Kreis
authors.forename: Esther
authors.initials: E
authors.lastname: Middelkoop
mesh_terms: D000328:Adult; D002921:Cicatrix / Q000473:pathology*; D003094:Collagen / Q000648:ultrastructure*; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007596:Joints / Q000502:physiology; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D012867:Skin / Q000473:pathology*; D013718:Tensile Strength; D013997:Time Factors; D014945:Wound Healing / Q000502:physiology*
chemical_list: D003094:Collagen