Impact of polyclonal anti-thymocyte globulins on the expression of adhesion and inflammation molecules after ischemia-reperfusion injury.

BACKGROUND: Polyclonal anti-thymocyte globulins (ATGs) are immunosuppressive agents used for the treatment and prevention of acute organ rejection after transplantation. ATGs induce apoptosis and complement-mediated cell death in peripheral T-lymphocytes and have shown a reduction of leukocyte adhesion after ischemia-reperfusion (IRI). We analyzed the impact of different ATGs upon the expression of adhesion and inflammation molecules after IRI.

MATERIALS AND METHODS: The major arteries and veins of the extremities of cynomolgus monkeys were surgically isolated and flushed with Ringer's lactate at 4 degrees C. After 60 min of ischemia the limbs were reperfused with matching human blood. ATGs were added to the blood 30 min prior to the reperfusion, forming four groups: Tecelac-ATG group (n=16), Fresenius(S)-ATG group (n=16), Thymoglobulin-ATG group (n=12) and a control group (n=16). Biopsies from muscular tissue were obtained after the experiments. The expression of adhesion (ICAM-1, VCAM, PECAM, CD11b, CD62E) and inflammation (IL-1, IL-6, TNF-alpha) molecules on endothelium, leukocytes, and reperfused tissue was analyzed by means of immunohistochemistry.

RESULTS: The expression of the studied adhesion molecules (ICAM-1, VCAM, PECAM, CD11b, and CD62E) was significantly increased in the control group when compared with the treated groups. The expression of IL-1, IL-6, and TNF-alpha was reduced in the ATG-groups in comparison to the control group.

DISCUSSION: Our results showed that ATGs caused a reduction of the expression of adhesion and inflammation molecules both in endothelium and reperfused tissue. The inhibition of the expression of molecules required for firm cellular adhesion, may contribute to decreasing cellular graft infiltration after post-ischemic reperfusion.