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Promoted activation of matrix metalloproteinase (MMP)‐2 in keloid fibroblasts and increased expression of MMP‐2 in collagen bundle regions: implications for mechanisms of keloid progression
Author(s) -
Imaizumi Risa,
Akasaka Yoshikiyo,
Inomata Naomi,
Okada Emi,
Ito Kinji,
Ishikawa Yukio,
Maruyama Yu
Publication year - 2009
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1111/j.1365-2559.2009.03287.x
Subject(s) - keloid , matrix metalloproteinase , extracellular matrix , collagenase , chemistry , pathology , wound healing , fibroblast , type i collagen , collagen, type i, alpha 1 , scars , zymography , tissue inhibitor of metalloproteinase , western blot , biology , medicine , immunology , biochemistry , enzyme , gene , in vitro
Aims: Keloid is characterized by excessive deposition of collagen, resulting from aberrant extracellular matrix (ECM) production and degradation. The aim was to investigate the role of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) in pathological wound healing in keloids. Methods and results: Semiquantitative analysis of 60 keloid tissue samples and 25 mature scar tissue samples demonstrated significantly increased expression of MMP‐2, TIMP‐2 and TIMP‐3 in keloids compared with mature scars. Within keloid regions, MMP‐2 expression was significantly higher in collagen bundle regions than in non‐collagen bundle regions. Double immunofluorescence revealed that keloid fibroblasts between collagen bundles exhibited MMP‐2, TIMP‐2 and membrane‐type 1 MMP (MT1‐MMP) co‐expression, whereas only MMP‐2 expression was evident on the edge of collagen bundles. Western blot analysis and gelatin zymography of 13 keloid‐derived fibroblasts (KFbs) and six normal skin dermal‐derived fibroblasts (NFbs) demonstrated that unstimulated KFbs exhibited significantly increased MMP‐2 activity and expression compared with NFbs under the same conditions. Conclusions: These results together indicate that MMP‐2 activity can be promoted in keloid fibroblasts between collagen bundles in cooperation with TIMP‐2 and MT1‐MMP. This could contribute to remodelling of collagen bundle regions and invasion of fibroblasts into peripheral normal regions through promoted degradation of ECM.