Characteristics of growth, morphology, contractility, and protein expression of fibroblasts derived from keloid

Phenotypic alterations of keloid-derived fibroblasts were characterized by comparison with the phenotypes of normal fibroblasts from the same patient. Explant cultures of keloids showed unique features. Keloid explants contracted considerably and reduced their size during culture, whereas the size of normal skin explants remained unchanged. Enlarged cells were found among fibroblasts which had grown out of all the explants and were morphologically distinct from fibroblasts; however, keloid explants produced many more of them than did the normal tissues. The growth rate of fibroblast colonies formed from normal explants was five times higher than keloid explants. Keloid fibroblasts which had been serially cultivated contracted lattices of collagen gels at a rate similar to normal fibroblasts. Proteins extracted from serially cultivated fibroblasts were mapped on polyacrylamide two-dimensional electrophoretic gels. No significant qualitative alterations in protein expression in keloid cells were found as compared with normal fibroblasts. However, some quantitative changes were found between the two. A computer-assisted image analyzer detected 151 polypeptide spots—50 spots (33%) of which increased their amounts in keloid cells, whereas 34 spots (22.5%) decreased in comparison with normal fibroblasts. Sixteen major polypeptides were identified as known proteins with the aid of time-of-flight mass spectrometry. The level of expression of these identified proteins was similar between normal and keloid cells, except stathmin whose expression was suppressed in keloid fibroblasts.