The time-dependent rearrangement of the epithelial basement membrane in human skin wounds —immunohistochemical localization of Collagen IV and VII

Abstract

S u m m a r y . In 62 human skin wounds (surgical wounds, stab wounds and lacerations after surgical treatment) we analyzed the immunohistochemical localization of collagen IV in the epithelial basement membrane. In 27 of these wounds the distribution of collagen VII, which represents a specific component of the basement membrane of stratified epithelia, was also analyzed. We were able to demonstrate a virtually identical co-distribution of both collagen IV and VII in the wound area with no significant time-dependent differences in the appearance of both collagen types. Fragments of the epithelial basement membrane could be detected in the wound area from as early as 4 days after wounding and after 8 days a complete restitution of the epithelial basement membrane was observed, in all cases with a wound age of more than 21 days the basement membrane was completely reformed over the former lesional area. The period between 8 and 21 days after wounding was characterized by a wide variability ranging from complete restitution to deposition of basement membrane fragments or total lack of the epidermal basement membrane. K e y words: I m m u n o h i s t o c h e m i s t r y - Schliisselwiirter: I m m u n h i s t o c h e m i e -Kollagen IVKollagen VII -Basalmembran -Wundalter I n t r o d u c t i o nImmunohistochemistry is not only useful for the detection of early changes during wound repair [3], but also provides significant information on the time-dependent appearance of various extracellular matrix components during the proliferative and reparative phases of wound healing.In open skin wounds the closure of the wounded skin surface by reepithelialization starts from undamaged skin. Dividing basal cells of the epidermal layer proliferate to cover the lesional area. This migration is directed towards the wounded region [13]. Experimental studies have provided evidence that the migration of these epithelial cells is associated with the formation of a provisional matrix consisting of fibrin and fibronectin and that the basement membrane components laminin and collagen IV reappear when the fibrin and fibronectin in the wound area are organized [5].The epidermal basement membrane is composed not only of laminin and collagen IV, but also contains collagen VII which is specific for the basement membrane. This unique collagen molecule forms the anchoring fibrils. Collagen VII has been localized exclusively in the basement membrane of the epidermis and other basement membranes of stratified epithelia [20].The time-dependent rearrangement of the epithelial basement membrane component collagen IV in human

Immunohistochemical localization of collagen types I and VI in human skin wounds

“…Our own previous studies provided considerable evidence that the immunohistochemical detection of collagens III, IV and V show distinct time courses of appearance of the collagen types [3,4,5]. Less information is available for collagen I.…”

“…In addition, postmortem wounds and uninjured skin were analyzed. The specimens were obtained and prepared as previously described [3,4,5].…”

“…The use of the immunohistochemical detection of collagen types I, III and IV for a forensically applicable wound age-determination has previously been shown by Eisenmenger et al [7], while studies dealing with the time-dependent appearance of collagen types III, IV, V and VII have been performed by Betz et al [3,4,5].…”

The time-dependent expression of keratins 5 and 13 during the reepithelialization of human skin wounds

“…3 days before a complete rearrangement of the epithelial basement membrane occurs [1]. This difference can be explained by the observation that epithelial cell seem to synthesize -at least partly -the basement membrane components and therefore appear before basement membrane material is detectable.…”

“…They can be subdivided into 8 type II (1)(2)(3)(4)(5)(6)(7)(8) and 12 type I keratins (9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) [10,11,12] and 2 cytokeratins in combination (one type I and one type II) form an intermediate filament [4,21].…”