Fully automatic d-lactate assay using a modified commercially available method.

Intestinal infarction is the fast-evolving endpoint of impaired blood perfusion to an intestinal segment which may have fatal outcome. Early diagnosis and treatment within 6 h reduce mortality. Currently, d-lactate is a promising biomarker, however, not available in the acute clinical setting. The aim of this study is implementation of d-lactate analysis in a routine clinical setting. We used a spectrophotometric method, based on enzymatic oxidation of d-lactate by d-lactate dehydrogenase (D-LDH) coupled to the reduction of nicotinamide-adenine dinucleotide (NAD+). The amount of NADH formed in this reaction is equivalent to d-lactate. The primary concern in this method is interfering NADH formed by oxidation of l-lactate by l-lactate dehydrogenase (L-LDH). A commercially available kit for d-lactate measurement was implemented on our existing automated routine laboratory equipment including pH-inactivation of L-LDH. Our setup fulfilled clinical quality goals. We were able to measure d-lactate with an acceptable performance of the analysis and a short turn-around time. The method can be used to distinguish between the expected cut-off for intestinal ischemia around 0.3 mM and the upper reference limit of 0.05 mM. With a turnaround time of just 9 min, the analysis has potential as a readily available detection of circulating d-lactate for early diagnosis of intestinal ischemia.

Dobutamine Versus Vasopressin After Mesenteric Ischemia.

BACKGROUND: Gastrointestinal blood flow may be compromised during and after vasopressor support. Endothelin expression may lead to microcirculatory dysfunction. The aim of this study was to analyze the effect of vasopressin and dobutamine after mesenteric ischemia on the gastrointestinal mucosal microcirculation, endothelin expression, and morphologic injury. MATERIALS AND METHODS: Pigs were studied in four groups (six pigs in each group): 1, sham; 2-4 ischemia (1 h superior mesenteric artery occlusion with 30 min reperfusion and 30 min of vehicle [2], dobutamine [3], or vasopressin [4] administration, followed by 30-min break and thiopental-induced hypotension [3, 4]). Blood flow of the gastric, jejunal, and rectosigmoidal mucosa was measured. At the end of the experiment, the mucosal expression of endothelin-1 (ET-1) and its receptor subtypes A (ETA) and B were determined by polymerase chain reaction. Mucosal injury, apoptotic cell death, and leukocytic infiltration were determined by histology and immunohistochemical analysis of cleaved caspase-3 and myeloperoxidase. RESULTS: Mesenteric ischemia increased jejunal mucosal ET-1 gene expression, arterial ET-1, intestinal fatty acid binding protein, and jejunal mucosal injury compared with sham. Dobutamine increased arteriovenous shunting at the cost of the jejunal mucosal blood perfusion. This was associated with an increased expression of ET-1 and ETA and mucosal leukocytic infiltration. In contrast, vasopressin increased postischemic capillary density and tissue blood flow. This was associated with a lower ET-1 gene expression. Vasopressin did not induce jejunal mucosal leukocytic infiltration. CONCLUSIONS: Vasopressin reduces mesenteric ischemia-associated alterations of the microcirculation and tissue integrity, whereas dobutamine does not.

Cold-inducible RNA-binding protein-derived peptide C23 attenuates inflammation and tissue injury in a murine model of intestinal ischemia-reperfusion.

BACKGROUND: Cold-inducible RNA-binding protein is a novel damage-associated molecular pattern that causes inflammation. C23, a short peptide derived from cold-inducible RNA-binding protein, has been found to have efficacy in blocking cold-inducible RNA-binding protein's activity. We hypothesized that C23 reduces inflammation and tissue injury induced by intestinal ischemia-reperfusion. METHODS: Male C57BL/6 mice were subjected to 60 minutes of intestinal ischemia by clamping the superior mesenteric artery. Immediately after reperfusion, either normal saline (vehicle) or C23 peptide (8 mg/kg body weight) was injected intraperitoneally. Four hours after reperfusion, blood, intestinal, and lung tissues were collected for analysis of inflammatory and tissue injury parameters. RESULTS: Cold-inducible RNA-binding protein levels in the intestinal tissues were significantly increased following intestinal ischemia-reperfusion. Histologic examination of the intestine revealed a significant reduction in injury score in the C23 group by 48% as compared with the vehicles after intestinal ischemia-reperfusion. The serum levels of lactate dehydrogenase and aspartate aminotransferase were increased in animals that underwent vehicle-treated intestinal ischemia-reperfusion, whereas C23-treated animals exhibited significant reductions by 48% and 53%, respectively. The serum and intestinal tissue levels of tumor necrosis factor α were elevated in vehicle-treated intestinal ischemia-reperfusion mice but decreased by 72% and 69%, respectively, in C23-treated mice. Interleukin-6 mRNA levels in the lungs were reduced by 86% in the C23-treated group in comparison to the vehicle-treated group after intestinal ischemia-reperfusion. Expression of macrophage inflammatory protein 2 and level of myeloperoxidase activity in the lungs were dramatically increased after intestinal ischemia-reperfusion and significantly reduced by 91% and 25%, respectively, in the C23-treated group. CONCLUSION: C23 has potential to be developed into a possible therapy for reperfusion injury after mesenteric ischemia and reperfusion.