021 Altered in Vitro Migratory Activity of Human Fibroblasts Isolated from Type I Diabetics

Abstract

An essential cell behavior for wound healing is the ability of reparative cells to migrate into a wound site. Impairment of this migratory behavior could delay or potentially halt the healing process, allowing for infection or other secondary insults to the wound. Type I diabetics experience significant morbidity from failure of lower extremity injuries to heal. Various hypotheses have been proposed to explain this impaired healing response, but little is known about intrinsic migratory differences in the fibroblasts that populate the diabetic dermis prior to wounding. Nontransformed fibroblast cell lines from type I diabetics were obtained from the NIGMS-NIH cell repository at the Coriell Institute. Cells were maintained in Dulbecco’s modified Eagle’s medium containing 10% fetal calf serum, penicillin, streptomycin, and either 25 mM (high) or 5.6 mM (low) glucose. Cell migration was measured over 72 hr by two methods; the monolayer scrape method, or by quantifying the movement of cells away from a circular source of cells, deposited within cloning rings, under high- or low-glucose conditions. The initial (0, 6, 24, and 48 hr) proliferative response of cells was measured by 3H-thymidine incorporation into confluent cell monolayers following partial scraping of the cell layer. Using the scrape method, diabetic cells failed to start moving across a monolayer scrape until > 10 hrs, whereas normal fibroblasts had started migrating at 8 hrs and were noticeably closing the scrape “wound” by 10 hours. Consistent with this finding, fibroblasts from diabetics showed impaired migration (70% vs. 145% increase in diameter) in high glucose over an initial 72 hrs in the second migration assay. This difference was less if the cells were cultured and tested in low glucose medium. In contrast, diabetic derived cells incorporated 3H-thymidine more rapidly at early times (55.9%[24 hr] and 72%[48 hr]) when cultured under high-glucose conditions. These results suggest that fibroblasts in the type I diabetic are characterized by a reduced capacity to migrate, but a normal or heightened proliferative capacity. This may indicate that injury to this connective tissue fails to produce the required influx of fibroblasts to deposit new matrix.