Endothelial thrombomodulin (CD 141) in a rabbit burn model

Thrombomodulin (CD 141) is an endothelial surface transmembrane glycoprotein. It is involved in the activation of protein C in the inactivation of thrombin. In severe sepsis CD 141 is shed from the endothelial surface. This leads to disseminated intravascular coagulation (DIC), disturbed organ functions and multi organ failure (MOF). In this study, we investigated if endothelial bound thrombomodulin is shed in thermal injuries.

In 10 New Zealand white rabbits full thickness and superficial partial thickness burns were produced. Dermal blood flow was analyzed by measuring the fluorescence of intravenously injected indocyanine green. Skin-biopsies were taken from the burn wounds from the zones of stasis between full thickness burns and from unburned skin 72 h post burn. Specimens were processed for immunoperoxidase staining using a specific monoclonal antibody against CD 141.

Dermal blood flow was reduced in burned skin areas and in the zones of stasis. Thrombomodulin was only detectable on the surface of capillary endothelial cells in specimens taken from unburned skin areas. No thrombomodulin was detectable in specimens taken from burn wounds or from the zones of stasis. Thus, shedding of thrombomodulin was detectable in areas with reduced dermal blood flow.

Thermal injuries affect the dermal endothelial surfaces resulting in a shedding of thrombomodulin. This mechanism might be involved in the development of progressive skin damage in the zone of stasis. Disseminated intravascular coagulation following inactivation of thrombomodulin might lead to multiple organ dysfunctions in severe burn injuries.