Gut Luminal Lactate Measured by Microdialysis Mirrors Permeability of the Intestinal Mucosa After Ischemia

Abstract

The aim of the present study was to investigate the influence of a prolonged initial intestinal ischemic insult on transmucosal permeability after a subsequent ischemic event and whether microdialysis of biomarkers released to the gut lumen is able to reflect changes in intestinal permeability. The superior mesenteric artery was cross-clamped for 60 min followed by 4 h of reperfusion in 16 pigs. Nine pigs had a second cross-clamp of 60 min and 3 h of reperfusion, whereas seven pigs were observed for a further 4 h of reperfusion. Intestinal mucosal integrity was assessed by permeability of C-polyethylene glycol (PEG-4000) over the gut mucosa, luminal microdialysis of lactate, glucose and glycerol, and tonometry. During reperfusion, the PEG-4000 amount in venous blood was two times higher after the first than after the second ischemia (area under the curve, 44,780 [13,441-82,723] vs. 22,298 (12,213-49,698] counts min mL(-1), P=0.026 [mean {range}]). There was less lactate detected in the gut lumen after the second ischemia compared with the first (area under the curve, 797 [412-1,700] vs. 1,151 [880-1,969] mmol min L(-1), P=0.02) and a lower maximum concentration (4.8 [2.7-9.4] vs. 8.5 [5.0-14.9] mM, P=0.01). The same pattern was also seen for luminal glycerol and glucose. During the second ischemia, the intestinal mucosal/arterial CO2 gap was identical to the level during the first ischemic episode. A prolonged ischemic insult of the intestine confers protection, for reduced hyperpermeability against further ischemia. Microdialysis of biomarkers mirrors permeability changes associated with this type of protection. Lactate reflects permeability across the intestinal mucosa more precisely than glycerol.

Intestinal ischemia/reperfusion: microcirculatory pathology and functional consequences

“…Several techniques are available to study the microcirculation of the intestine. Deteriorations of the intestinal microcirculation can be assessed indirectly by analyzing tissue oxygenation with Clark electrodes or by monitoring intramucosal pH (pHi) and pCO 2 (PiCO 2 ) using tonometry [17][18][19][20]. In addition, tissue reflectance spectrophotometry may give information on microvascular hemoglobin oxygen saturation (HbO 2 ) and Laser Doppler velocimetry can assess relative changes of microvascular blood perfusion [21,22].…”

“…Langenbecks Arch Surg (2011) 396:[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] …”

Serum from Patients Undergoing Remote Ischemic Preconditioning Protects Cultured Human Intestinal Cells from Hypoxia-Induced Damage: Involvement of Matrixmetalloproteinase-2 and -9

“…Animal studies and clinical observations revealed that ischemia leads to increased permeability of the intestinal epithelial barrier, resulting in translocation of pathogenic bacteria and endotox- ins (12)(13)(14). As a consequence, inflammation, sepsis and multiorgan failure may develop, leading to life-threatening conditions (14)(15)(16)(17).…”

Intraperitoneal Microdialysis as a Monitoring Method in the Intensive Care Unit

“…Glucose levels are reduced inside the mesenteric vessels, intraluminally, but also intraperitoneally. 13 During this study, the L/P ratio remained at high levels for the first 3 days of hospitalization. In fact, an L/P ratio of 25.94 is recommended as a baseline value, over which the survival rate is significantly decreased, as clearly observed in this study.…”