Group specific (Gc) globulin also known as vitamin D-binding protein is part of the extracellular actin-scavenging system that removes actin from the circulation. Actin is an intracellular structural protein, which is released to blood in patients with tissue injury and cell death. Circulating actin forms filaments, which cause microthrombi and endothelial injury. These effects of circulating actin are extremely harmful, and high levels of free actin are potentially lethal. Gc-globulin binds to actin and removes it from the circulation via the reticuloendothelial system. Plasma concentrations of Gc-globulin decrease after conditions causing tissue injury and cell death, for example physical trauma, sepsis, experimentally induced endotoxemia or liver failure. In humans, decreases in Gc-globulin levels are observed within 60 minutes after trauma. Studies in humans and laboratory rodents have shown that very low concentration of plasma Gc-globulin are related to an increased risk of developing shock and lethal complications of trauma. Gc-globulin is thus a prognostic marker in intensive care medicine.

It has been suggested that treatment with Gc-globulin to patients with severe tissue injury can prevent development of shock and thereby increase survival chances. The in vivo toxicity of Gc-globulin infusion is currently being investigated in horses and other species.

Gc-globulin has been demonstrated in horse plasma and its structure closely resembles that of human Gc-globulin. Gc-globulin concentrations in horses under clinical conditions have never previously been investigated.

The Ph.D. project focuses on Gc-globulin as a prognostic marker in horses with acute abdominal pain.