Plasma biomarkers in ischemia and reperfusion in acute occlusion of the superior mesenteric artery: a rat model study.

Acute mesenteric ischemia (AMI) remains a life-threatening condition with high mortality rates due to the lack of sensitive biomarkers for early diagnosis. We investigated phase-specific biomarker profiles using a Sprague-Dawley rat model of superior mesenteric artery occlusion to distinguish between ischemic and reperfusion injuries. Rats were assigned to control, ischemia (1 h clamping), and reperfusion (1 h ischemia followed by 2 h reperfusion) groups. We analyzed serum levels of albumin, intestinal fatty acid-binding protein (I-FABP), lactate dehydrogenase (LDH), creatine phosphokinase (CPK), ischemia-modified albumin (IMA), and C-reactive protein (CRP), associating them with histopathological severity. Our results demonstrated distinct temporal profiles: during the early ischemic phase, serum albumin levels significantly decreased (P < 0.001) and showed a strong negative association with mucosal injury severity, likely reflecting immediate endothelial dysfunction. Conversely, the levels of traditional markers such as I-FABP and LDH did not change significantly during ischemia but exhibited a sharp increase (P < 0.001) during the reperfusion phase, associating strongly with tissue necrosis. These findings suggest albumin as a surrogate marker for early ischemic injury, while I-FABP and LDH are potential robust indicators of reperfusion damage. While our findings provide important pathophysiological insights, direct clinical application requires a cautious and realistic approach, as these biomarkers may have limited value for primary diagnosis in typical clinical settings.