PROTEIN C ACTS AS AN ACUTE PHASE REACTANT IN EQUINE LAMINITIS
Equine Colic Syndrome is a disease of horses whose complications include laminatis.This term describes a situation where microvascular damage to the hoof causes degeneration of the interphalangeal laminae,leading to lameness. Vascular studies have suggested that microthrombosis involving the delicate vessels in the hoof,coupled with changes in the platelet count, coagulation factors & elevated FDP's implicate DIC as a potential etiology. Limited test capability in the horse has limited further evaluation of this hypothesis. We have developed an assay for equine protein C activity,our normal range being 70-60% (Mean+/- 2SD). We studied 12 horses with the disease for 5 consecutive days,drawing 1 blood sample per day. Our expectation was that protein C levels would decrease.if DIC was significant,as would be expected in humans. No significant decrease was noted in any horse. However there was a significant increase in the protein C levels beyond the upper limit of the normal range in 10 of the 12 horses by the third day. Five of the 10 horses maintained this elevation beyond the 5th day. Thus protein C changes were more consistent with an acute phase reactant response,rather than reflecting the decrease we anicipated,if the equine DIC parallels human DIC. We are measuring other acute phase reactants to see if equine protein C parallels those. Since our assay is still being evaluated,more data needs to be obtained in this and other equine disease states before any definative role for protein C in equine pathology can be determined. In our laminitis horses,we are devolping assays for antithrombin III and plasminogen which should allow us to evaluate the disease state more completley for any involement of elements of intravascular thrombosis and fibrinolysis in the equine colic syndrome.