Epidermal Protein C Levels Correspond to Local Injury Severity and Increased Clinical Support in Burn Patients

Abstract

The protein C (PC) system has proven to be a crucial cascade in systemic inflammatory and coagulopathic disorders such as severe sepsis and, more recently, in severe burns. We aimed to conflate our recent systemic findings with further investigations in the local tissue effects of a severe burn injury on the expression of PC and its main receptor endothelial protein C receptor (EPCR). Of the 86 patients enrolled in our recent study, 34 consented to biopsies of both normal and burn edge tissue. These were examined histologically and immunostained for PC, EPCR, and CD68. The burn samples expressed lower PC (p = 0.0027) and higher EPCR (p = 0.0253) than the normal samples in a histological severity-dependent manner. There was also a negative association between PC expression and CD68 positive macrophage infiltration (τb = −0.214, p = 0.020), which was expectedly higher in burn edge samples (p < 0.0005). Interestingly, while there were no correlations between tissue and plasma PC or EPCR, local PC expression was also prognostic of our previously established outcome of a patient requiring increased medical support (OR 0.217 (95%CI 0.052 to 0.901), p = 0.035). The results suggest that local PC cascade changes from a burn injury may be a separate process to the systemic effects and that the local levels may provide useful information in addition to the diagnostic and prognostic abilities we previously found in the circulating PC system.