Searching for the molecular benchmark of intestinal anastomotic healing in rats: an experimental study

Objective: Intestinal anastomotic healing processes differ greatly from analogous more widely-researched cutaneous phenomena. To date, we still lack comprehension of the particularities of the physiology of intestinal healing. Here, we examine the mRNA response time course to formation of an anastomosis.

Materials and methods: In 8 rats, end-end ilio-ilial anastomoses were performed (n=2 per group). At days (d) 0 (control), 2, 4 and 8 10mm anastomotic segments were resected and examined by Affymetrix microarray (RG-230; >31000 probe sets) to assess changes in gene regulation. In addition to seeing the global time course of significantly up- or down-regulated mRNA during healing, we created time curves of genes known to be crucially involved in physiological anastomotic wound healing as well as potential new target genes. Finally, we examined which molecular pathways are involved in physiological intestinal healing, subjecting data to a Genetrail overrepresentation analysis.

Results: Compared to the control group, we observed a biological time curve of differenzially regulated genes peaking on day 2 with a total of 2238 genes decreasing by day 4 to 1687 genes and levelling at 1407 genes by day 8. When setting the cut-off of up-regulation at e.g. 10-fold to identify more likely relevant genes, the gene count was significantly lower with 58, 47 and 39 genes on days 2, 4 and 8 respectively. The regulation of these genes was seen to have a consistent, specific time curve (e.g. MMP family, ILs, chemokines). Similar to mRNA expression levels, the number of involved pathways was seen to decrease over time. Just as pathways involved in wound healing and inflammation were up-regulated, pathways thus far not linked to anastomotic healing were identified.

Conclusion: This study is the first of its kind that describes and proposes a possible benchmark of the physiological process of intestinal anastomotic healing on a molecular level. Only a more profound understanding of the physiology of anastomotic healing will allow an advance in pinpointing the pathophysiological mechanisms of disturbed healing and consecutive anastomotic insufficiency.