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Altered Posttranslational Modifications of Collagen in Keloid

1998; Elsevier BV; Volume: 249; Issue: 3 Linguagem: Inglês

10.1006/bbrc.1998.8955

1090-2104

Katsuhiro Uzawa, Melanie K. Marshall, Elton P. Katz, Hideki Tanzawa, Heather N. Yeowell, Mitsuo Yamauchi,

Wound Healing and Treatments

Keloid is a tissue with an excessive accumulation of collagen. In this study, we have partially characterized post-translational modifications of type I collagen in human keloid in order to pursue their potential involvement in this pathology. The levels of lysyl hydroxylation of the helical portions of α1 and α2 chains of type I collagen in keloid were significantly higher than those of normal, while the levels of prolyl hydroxylation were identical between these two groups. The contents of the major reducible cross-links in dermal collagen, dehydro-hydroxylysinonorleucine and dehydro-histidinohydroxymero-desmosine, were both significantly higher in keloids (up to sixfold) than those of normal. In addition, significant amounts of hydroxylysine-aldehyde derived cross-links that are characteristic of skeletal tissue collagens, dehydro-dihydroxylysinonorleucine (about 0.3 mole/mole of collagen) and pyridinoline (about 0.1 mole/mole of collagen), were found in keloids. These results indicate that keloid-forming cells are phenotypically different from those in normal dermis and that the collagen produced is highly cross-linked. The increased cross-linking provides the fibrils with more stability that may result in an accumulation of collagen.