Clinical relevance of monocyte procoagulant activity in horses with colic

Abstract

Summary Endotoxin-activated monocytes express a thromboplastin-like procoagulant activity on the cell surface that may serve as a focal point for formation of microvascular thrombi. Because coagulopathy is a common sequela to endotoxemia in the equine species, we investigated the ability of monocytes, isolated from horses with colic, to express procoagulant activity. On the day of admission, and on the third and fifth day of hospitalization, monocytes were isolated from 30 adult horses with colic. A coagulation profile, including prothrombin time, activated partial thromboplastin time, thrombin time, and plasma fibrinogen and serum fibrin degradation products concentrations, was determined at each sample collection. The concentration of endotoxin in the plasma was quantitated at the time of admission. Ten clinically normal adult horses served as controls. The procoagulant activity of monocytes isolated from horses with colic was significantly (P < 0.05) greater than that of the monocytes isolated from clinically normal horses. On the first and third day of hospitalization, the mean prothrombin time was significantly (P < 0.05) longer in horses with colic, compared with clinically normal horses, and was the most common abnormality in the coagulation profile on the day of admission (25/30; 83%). Mean fibrin degradation products concentration was significantly (P < 0.05) greater in horses with colic on the day of admission and was the second most common abnormality in the coagulation profile on day 1 (23/30; 77%). In horses with colic, the mean prothrombin and activated partial thromboplastin times were significantly (P < 0.05) longer in horses that did not survive, compared with horses that survived. Of the 30 horses with colic, 9 had detectable endotoxin in the plasma at the time of admission. The presence of endotoxin in the plasma was useful in predicting survival in horses with colic; all horses with plasma endotoxin concentration ≥ 10 pg/ml (6/6) did not survive.