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Hepatoenteric ischemia-reperfusion increases circulating heparinoid activity in rabbits
1Department of Anesthesiology, The University of Alabama at Birmingham, 35249, USA.
Journal of Critical Care
|January 4, 2001
Summary
Increased heparinoid activity significantly impairs blood clotting during hepatoenteric ischemia-reperfusion in rabbits. This finding highlights a key factor in the hemostatic disorder observed in this condition.
Area of Science:
- Physiology
- Vascular Biology
- Coagulation Science
Background:
- Hepatoenteric ischemia-reperfusion (I/R) is a critical condition leading to significant hemostatic abnormalities.
- The precise mechanisms underlying these hemostatic derangements remain incompletely understood, particularly the role of circulating anticoagulants.
Purpose of the Study:
- To investigate the contribution of elevated heparinoid activity to the hemostatic dysfunction observed following hepatoenteric ischemia-reperfusion.
- To elucidate the role of heparinoids in the coagulation cascade during I/R events.
Main Methods:
- Anesthetized rabbits underwent thoracic aorta occlusion followed by reperfusion to induce hepatoenteric I/R.
- Hemostatic function was assessed using thrombelastography (TEG) measuring reaction time (R), clot formation speed (alpha), and clot strength (G).
- TEG analysis was performed on blood samples with and without heparinase (to neutralize heparinoids) and with or without a platelet inhibitor (cytochalasin D).
Main Results:
- Ischemia-reperfusion significantly impaired hemostatic function, indicated by increased R, decreased alpha, and decreased G values in blood with intact platelet function.
- The addition of heparinase to blood samples prevented the hemostatic abnormalities induced by ischemia-reperfusion, suggesting heparinoids were responsible.
- Similar results were observed in samples treated with a platelet inhibitor, indicating heparinoid activity impacts clotting independently of platelet function.
Conclusions:
- Elevated circulating heparinoid activity is a significant contributor to the hemostatic disorder observed in rabbit models of hepatoenteric ischemia-reperfusion.
- Neutralizing heparinoid activity restores normal hemostasis, underscoring its critical role in I/R-induced coagulopathy.
- These findings suggest therapeutic strategies targeting heparinoid activity could mitigate bleeding complications in I/R injury.