Fibroblasts facilitate re-epithelialization in wounded human skin equivalents

Abstract

The re-epithelialization of the wound involves the migration of keratinocytes from the edges of the wound. During this process, keratinocyte migration and proliferation will depend on the interaction of keratinocytes with dermal fibroblasts and the extracellular matrix. The present study aimed to investigate (1) the role of fibroblasts in the re-epithelialization process and on the reconstitution of the dermal-epidermal junction (DEJ) and (2) differential protein expression during re-epithelialization. For both purposes, three-dimensional human skin equivalents (HSE) were used. A full-thickness wound in HSE was introduced by freezing with liquid nitrogen and a superficial wound by linear incision with a scalpel. The closure of the wound in the absence or presence of exogenous growth factors was followed by monitoring the rate of re-epithelialization and regeneration of the DEJ. The results obtained in this study demonstrate that fibroblasts facilitate wound closure, but they differentially affected the deposition of various basement membrane components. The deposition of laminin 5 at the DEJ was delayed in superficial wounds as compared to the full-thickness wounds. During freeze injury, some basement membrane (BM) components remain associated with the dermal compartment and probably facilitate the BM reconstitution. The re-epithelialization process in full-thickness but not in superficial wounds was accelerated by the presence of keratinocyte growth factor and especially by epidermal growth factor. In addition, we have examined the deposition of various basement membrane components and the differences in protein expression in a laterally expanding epidermis in uninjured HSE. Laminin 5, type IV and VII collagen deposition was decreased in the laterally expanding epidermis, indicating that the presence of these proteins is not required for keratinocyte migration to occur in vitro. Using two-dimensional polyacrylamide gel electrophoresis, we have identified DJ-1, a protein not earlier reported to be differently expressed during the epithelialization process of the skin.

LL-37-Derived Peptides Eradicate Multidrug-Resistant Staphylococcus aureus from Thermally Wounded Human Skin Equivalents

“…HSEs are air-exposed threedimensional human skin models that mimic the native skin to a high degree. They can be used to study many properties of the human skin, including barrier properties (16) and wound healing (31). Furthermore, HSEs have been used to study skin colonization with MRSA (32,33).…”

“…Generation of human skin equivalents. Human skin equivalents (HSEs) were generated as described earlier (31). In short, 3 ml of rat tail collagen (4 mg/ml) was mixed with 1.25 ϫ 10 5 NHF.…”

“…HSEs were thermally wounded, as described earlier (30,31). In brief, wounds were created on 10-day air-exposed models using a 2 by 10 mm blunt metal bar, which was placed in liquid nitrogen for 2 min.…”

Relevance and Perspectives of Experimental Wound Models in Wound Healing Research

“…For these studies, some special in vitro wound model is used to study the effect of fibroblast on re-epithelialization in wounded human skin equivalents [23]. In these models cells are grown on silicon discs or on Petri dishes in monolayer and then cells from center are removed either cutting out disc or by means of a silicon rod.…”

Lactoferrin as an Adjunctive Agent in the Treatment of Bacterial Infections Associated with Diabetic Foot Ulcers

“…Numerous subtypes of keratinocytes (Patel et al, 2006) and fibroblasts (El Ghalbzouri et al, 2004) play an essential role in scar tissue formation by contributing to wound reepithelialization. In the early response to injury, re-epithelialization occurs when fibroblasts in the neighborhood of the wound proliferate and then migrate to the wound bed, where they are induced by chemotactic mediators to produce extracellular matrix components (Hardy, 1989).…”