In Vivo Observation of Mesenteric Leukocyte-Endothelial Interactions After Cecal Ligation/Puncture and Surgical Sepsis Source Control

Abstract

Nakagawa NK; Jukemura J, Aikawa P, Nogueira RA, Poli-de-Figueiredo LF, and Sannomiya P. In vivo observation of mesenteric leukocyte-endothelial interactions after cecal ligation/puncture and surgical sepsis source control. Clinics. 2007;62(3):321-6. PURPOSE: Cecal ligation and puncture (CLP) has been used as a useful model for the induction of polymicrobial sepsis. Necrotic tissue resection and peritoneal lavage (REL) are the surgical procedures for controlling perforated appendicitis. The aim of this study was to evaluate leukocyte-endothelial interactions in the rat mesentery in vivo after CLP and REL. METHODS: Thirty-seven male Wistar rats (250-300 g) underwent laparotomy and were randomly assigned to the following groups: 1) SHAM; 2) CLP: animals submitted to CLP, 3) CLP+REL: animals submitted to CLP and REL. Mesenteric leukocyteendothelial interactions were studied by intravital microscopy assessed once in each animal (3-5 postcapillary venules, 15-25 µm diameter) 24 hours after intervention. Follow-up was performed in all animals; this included analysis of glycemia, lactate, hematocrit, white blood cell count as well as a functional score that was the sum of scoring on the following parameters: alertness, mobility, piloerection, diarrhea, encrusted eyes, and dirty nose and tail. RESULTS: None of the animals showed significant changes in body weight (265 ± 20 g) or in hematocrit levels (46% ± 2%) during the experimental protocol. Compared to SHAM animals, CLP animals showed an increased number of rolling (2x), adherent, and migrating leukocytes (7x) in the mesenteric microcirculation, an increase in blood glucose (136 ± 8 mg/dL), lactate (3.58 ± 0.94 mmol/L), white cell count (23,570 ± 4,991 cells/mm 3 ) and functional alterations (score 11 ± 1), characterized by impaired alertness and mobility, and presence of piloerection, diarrhea, encrusted eyes, and dirty nose and tail. The REL procedure normalized the number of rolling, adherent, and migrated leukocytes in the mesentery; glycemia; lactate; and white blood cell count. The REL procedure also improved the functional score (7 ± 1). CONCLUSION: Local and systemic inflammation was induced by CLP, while REL completely overcame the inflammatory process.

The Effects of Low and High Tidal Volume and Pentoxifylline on Intestinal Blood Flow and Leukocyte-Endothelial Interactions in Mechanically Ventilated Rats

“…19,[24][25][26] We report the data as median and interquartile range (IQR). We compared the groups with the Kruskal-Wallis test, and tested differences between groups with the Dunn Test.…”

“…However, leukocyte over-activation and increased leukocyte accumulation in the perivascular tissue can be associated with an exaggerated pro-inflammatory immune response that can contribute to widespread microvascular injury and consequent endothelial damage. 7,[24][25][26] Hypoperfusion of the gastrointestinal vascular bed has been suggested as a potential mechanism for the development of several complications from mechanical ventilation in critically ill patients. [8][9][10] We recently found that high intrathoracic pressure generated by high V T (10 mL/kg) and high PEEP (10 cm H 2 O) increased leukocyte-endothelial interactions in rat mesentery, as compared to PEEP values of 0 and 5 cm H 2 O, with no significant differences in mean arterial blood pressure between the groups.…”

“…[24][25][26] After midline abdominal incision, the distal ileum and its accompanying mesentery is exposed for examination of the microcirculation. The animal is placed in the right lateral decubitus on a warmed (37°C) stage, and the mesentery is transilluminated and kept moist with continuous applications of warm (37°C) Krebs solution.…”

“…We counted the number of rolling leukocytes as the number of white cells that passed a designated line perpendicular to the venular axis during a 10-min period. [24][25][26]28 We counted the number of adherent cells as the number of cells that remained stationary for Ͼ 30 seconds on a 100-m segment of the venular endothelium during a 10-min period. [24][25][26]28 We counted the number of migrated leukocytes as the number of cells accumulated at the connective tissue, adjacent to the chosen postcapillary venule, in a standard area of 5,000 m. [24][25][26] …”

“…19,[23][24][25] We recently found that injurious mechanical ventilation with a high V T (10 mL/kg) and a PEEP of 10 cm H 2 O markedly increased leukocyte-endothelial interactions in rat mesentery. 26 Lung-protective ventilation is the only treatment that has been shown to decrease mortality in patients with ARDS.…”