L- and D-lactate as biomarkers of arterial-induced intestinal ischemia: an experimental study in pigs.

Background: Intestinal ischemia is difficult to diagnose, and search for new biomarkers has led to interest in D-lactate, which arises from bacterial fermentation in the gastrointestinal tract.

Methods: The superior mesenteric artery was clamped in eight pigs for 6 h to induce ischemia of the intestine. Eight sham-operated pigs served as controls. Systemic and portal plasma D- and L-lactate were sampled in 1 h intervals. L-LDH was inactivated prior to D-lactate measurement by addition of NaOH.

Results: In systemic vein samples, we found a significant mean difference in the change of D-lactate from baseline to 6 h between the sham and intervention group (.007 ± .011 mmol/l vs. .030 ± .013 mmol/l, respectively) (P = .020). Both systemic and portal circulation levels of plasma L-lactate increased significantly between the two groups within an hour. The mean difference for L-lactate were -.020 ± .215 mmol/l and 1.440 ± 1.454 mmol/l in the sham and intervention group, respectively (P = .009).

Conclusion: L-lactate was found to be a marker of arterial-induced intestinal ischemia in both the systemic and portal circulation. There was no significant elevation of D-lactate at either site during the 6 h of ischemia.