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Bacterial translocation in mesenteric ischemia-reperfusion injury: is dysfunctional motility the link?
1David Paley Lichtenstein Laboratory of Surgical Metabolism and Nutrition, Children's Hospital of Philadelphia, PA 19104.
Abstract:
The authors previously reported that mesenteric ischemia and reperfusion (I/R) in a chronic newborn piglet model creates dysfunctional intestinal motility. Whether this leads to inadequate bacterial clearance and translocation (BT) through the gastrointestinal tract remains unclear. To test this hypothesis the authors used their chronic piglet model (weight, 3.5 +/- 0.3 kg; age, 18 +/- 4 days; on formula feeding); nonocclusive mesenteric ischemia was induced via reversible pericardial tamponade. Mesenteric flow (SMA Doppler measurement via the retroperitoneal approach) was decreased to 25% +/- 5% of baseline for 300 minutes in the ischemia group (n = 7) and followed by 14 hours of reperfusion in the I/R group (n = 6). Control subjects had a sham operation (n = 7). Mesenteric lymph nodes (MLN), liver (L), spleen (S), ileum, peritoneum, and blood were harvested for blind quantitative microbial analysis. Subjects in the control group had no cultures positive for growth. Eighty-five percent of animals in the ischemia group had positive MLN cultures only (P < .05 v control). All piglets in the I/R group had positive MLN cultures (P < .05 v control), and one third of them manifested bacteremia. Histological examination did not show mucosal disruption in any group. The validity of this model is confirmed by the negative cultures in the control group and by the presence of normal ileal flora in all animals. In the ischemia and I/R groups, MLN cultures were consistently positive with gram-negative bacilli (Escherichia coli and/or Klebsiella pneumoniae). When subjects of the I/R group had more than 1,000 colonies in the MLN, bacteremia with the translocating organisms was also identified.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Mesenteric ischemia and reperfusion (I/R) impairs bacterial clearance, leading to translocation (BT) and positive cultures in mesenteric lymph nodes. This piglet model demonstrates I/R-induced bacterial translocation and potential bacteremia.
Area of Science:
- Gastroenterology
- Surgical Research
- Microbiology
Background:
- Mesenteric ischemia and reperfusion (I/R) is known to cause dysfunctional intestinal motility in piglets.
- The impact of I/R on bacterial clearance and translocation (BT) within the gastrointestinal tract remains incompletely understood.
Purpose of the Study:
- To investigate whether mesenteric ischemia and reperfusion (I/R) in a chronic newborn piglet model leads to inadequate bacterial clearance and translocation (BT).
Main Methods:
- A chronic piglet model underwent nonocclusive mesenteric ischemia induced by pericardial tamponade, followed by reperfusion.
- Mesenteric blood flow was reduced to 25% of baseline for 300 minutes, with a subsequent 14-hour reperfusion period.
- Mesenteric lymph nodes, liver, spleen, ileum, peritoneum, and blood were analyzed for microbial growth.
Main Results:
- Control piglets showed no positive cultures, validating the model.
- Ischemia alone resulted in positive mesenteric lymph node (MLN) cultures in 85% of piglets.
- All piglets in the I/R group had positive MLN cultures, with one-third developing bacteremia, primarily with gram-negative bacilli like E. coli and K. pneumoniae.
Conclusions:
- Mesenteric ischemia and reperfusion significantly impairs bacterial clearance, leading to translocation into mesenteric lymph nodes.
- In severe cases (MLN >1,000 colonies), I/R can result in bacteremia with the translocating organisms.
- This piglet model effectively demonstrates I/R-induced bacterial translocation without significant mucosal disruption.