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Hydrated keratinocytes reduce collagen synthesis by fibroblasts via paracrine mechanisms
Author(s) -
Tandara Andrea A.,
Kloeters Oliver,
Mogford Jon E.,
Mustoe Thomas A.
Publication year - 2007
Publication title -
wound repair and regeneration
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.847
H-Index - 109
eISSN - 1524-475X
pISSN - 1067-1927
DOI - 10.1111/j.1524-475x.2007.00257.x
Subject(s) - paracrine signalling , keratinocyte , chemistry , scars , secretion , epidermis (zoology) , fibroblast , hypertrophic scar , microbiology and biotechnology , messenger rna , cytokine , biology , immunology , biochemistry , pathology , medicine , in vitro , anatomy , receptor , gene
Regulating collagen metabolism can control hypertrophic scars in cutaneous wounds. Hypertrophic scars can be reduced by occlusive dressings such as silicone sheeting; however, their mechanism is still unknown. We hypothesized that hydration of keratinocytes reduces the collagen secretion of fibroblasts by modifying the cytokine levels. Stratified human epidermal keratinocytes and confluent human dermal fibroblasts were co‐cultured serum free for 72 hours. Keratinocytes were either kept at the air interface or hydrated. Messenger RNA (mRNA) levels of interleukin‐1 (IL‐1)α, IL‐1β, tumor necrosis factor α (TNF‐α), keratinocyte growth factor (KGF), and procollagen‐1 were analyzed by real‐time reverse transcription‐polymerase chain reaction. Secretion of cytokines into conditioned media was quantified by enzyme‐linked immunosorbent assay and collagen content by Western blot. The content of collagen‐I decreased by 44% in the presence of hydrated keratinocytes. Co‐culture with air‐treated keratinocytes decreased collagen‐I only by 23%. Co‐cultured hydrated keratinocytes had significantly higher TNF‐α mRNA (172%) than hydrated keratinocytes. At the protein level, there was an overall trend toward increased TNF‐α levels in hydrated cultures. IL‐1β secretion decreased significantly under hydration (42% monoculture, 58% co‐culture). Co‐culture stimulated a 240% increase of KGF mRNA in fibroblasts compared with monocultured fibroblasts. Fibroblasts secreted 4.5‐fold more KGF in hydrated co‐cultures and sixfold more KGF in air‐treated co‐cultures. Hydration of keratinocytes modifies important paracrine interactions between keratinocytes and fibroblasts and reduces collagen‐1, which supports the hypothesis that hydration of the epidermis and restoration of water barrier function play an important role in scar formation.