Endothelin-1 levels in ischaemia, reperfusion, and haemorrhagic shock in the canine infrarenal aortic Revascularisation model

Endothelin-1 (ET-1) is a potent vasoconstrictive polypeptide produced from vascular endothelial cells. The effects of ischaemia, reperfusion, and exsanguination on plasma ET-1 levels were studied and compared in the mongrel dog after infrarenal aortic cross clamping. Ischaemia produced a trend toward increased ET-1 serum levels (p <0.07 with Bonferroni correction) that did not reach significance. Plasma ET-1 levels were significantly increased during reperfusion and even further elevations were found following exsanguination. We found a 2-3 fold increase in ET-1 levels following reperfusion (Initial 3.19 ± 0.27 pg/ml vs. Reperfusion maximum 6.32 ± 0.72 pg/ml, Bonferroni p <0.01). Haemorrhagic shock was associated with a 3-4 fold increase in ET-1 levels (Initial 3.19 ± 0.27 pg/ml vs. Exsanguination maximum 8.37 ± 0.97 pg/ ml Bonferroni p <0.001). These data reveal that ET-1 is released during reperfusion and exsanguination and may mediate remote vascular events associated with infrarenal aortic cross clamping and acute blood loss.