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 shown in pressure ulcers after 36 days of quality care. Average cell counts from multiple tissue sections showed that fibroblast nuclei were stained in decreasing order by antibodies to p21, p21/proliferating cell nuclear antigen (PCNA) and PCNA. P21 labeling suggested that the majority of ulcer fibroblasts were senescent. Fibroblast nuclei showing PCNA staining identified those fibroblasts that were capable of synthesizing DNA and contributing to pressure ulcer repair. Increased rates of wound closure were correlated with a decreasing number of p21 positive cells and an increasing portion of PCNA labeled cells. While the proportion of antigens appeared to correlate with 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 significant differences were observed in ulcer fibroblasts labeled with p21 at 0 and 10 days, however, the differences were significant after 36 days of quality care (p = 0.05, analysis of variance, post hoc Tukey test). The cellular contribution to pressure ulcer repair appeared to occur from ulcer fibroblasts that were capable of division, of emerging from quiescence, and that were successful in repairing their DNA.