TYPE-1 PROCOLLAGEN AS A MARKER OF SEVERITY OF SCARRING AFTER STERNOTOMY - EFFECTS OF TOPICAL CORTICOSTEROIDS

Aims-To determine whether the abundance of newly formed collagen in he aling surgical wounds correlated with scar severity, and whether topic al application of steroid cream reduced new collagen formation in pati ents who have undergone median sternotomy. Methods-Thirty three patien ts six weeks after sternotomy, and 12 controls were studied. Scars wer e photographed, and biopsy specimens from scars at sites treated or un treated with topical corticosteroids (clobetasol proprionate 0.5%) wer e examined using immunohistochemical staining for type 1 procollagen ( PCP 1) and transforming growth factor beta (TGF-beta), and in situ hyb ridisation for type 1 procollagen messenger RNA (mRNA). Results-The de gree of hypertrophy of the scar and the abundance of PCP 1 immunostain ing were ranked independently, blind, and a correlation between these two variables was observed (r = 0.604, p < 0.001). The PCP 1 immunosta ining was accompanied by a great abundance of PCP 1 mRNA and only a sl ight increase in TGF-beta immunostaining, when compared with normal sk in or mature scars. Following the application of topical corticosteroi ds, for either 48 hours or twice daily for seven days, there was no re duction in PCP 1 immunostaining nor the abundance of PCP 1 mRNA. Concl usions-These data suggest that the extent of new collagen formation as assessed by PCP 1 immunohistochemistry may be a useful marker of the exuberance of the scarring process following sternotomy, and that topi cal corticosteroids are ineffective in reducing this component of the fibrotic response.