Dynamic forces in the cell cycle affecting fibroblasts in pressure ulcers

Utilizing specific cell cycle markers of gene activity, temporal changes in the equilibrium of proliferating and non proliferating fibroblasts were sh own in pressure ulcers after 36 days of quality care. Average cell counts f rom multiple tissue sections showed that fibroblast nuclei were stained in decreasing order by antibodies to p21, p21/proliferating cell nuclear antig en (PCNA) and PCNA. P21 labeling suggested that the majority of ulcer fibro blasts were senescent. Fibroblast nuclei showing PCNA staining identified t hose fibroblasts that were capable of synthesizing DNA and contributing to pressure ulcer repair. Increased rates of wound closure were correlated wit h a decreasing number of p21 positive cells and an increasing portion of PC NA labeled cells. While the proportion of antigens appeared to correlate wi th the status of wound closure after 36 days of quality care, they did not always appear to reflect the final outcome of the pressure ulcer. No signif icant differences were observed in ulcer fibroblasts labeled with p21 at 0 and 10 days, however, the differences were significant after 36 days of qua lity care (p = 0.05, analysis of variance, post hoc Tukey test). The cellul ar contribution to pressure ulcer repair appeared to occur from ulcer fibro blasts that were capable of division, of emerging from quiescence, and that were successful in repairing their DNA.