Abstracts
1999 Digestive Disease Week

# 2173 SURGICALLY INDUCED LUMENOLYMPHATIC TRANSFERENCE OF MICROSPHERES: INTERACTION BETWEEN BACTERIAL LPS AND EXTRAVASATED MUSCULARIS LEUKOCYTES.
Nicolas T Schwarz, Donna Beer Stolz, Anthony J Bauer, Univ of Pittsburgh, Pittsburgh, PA

Intestinal manipulation initiates an intense inflammatory response within the intestinal muscularis, which results in muscle suppression and lumenal bacterial overgrowth. This study is investigating this interplay. ACI rats were subjected to small bowel manipulation, after which fluorescent (0.1-2.0µm) or paramagnetic (0.4µm) microspheres were intralumenally administered. Animals were sacrificed at 0, 0.5, 1, 3, 6, 12, 18 and 24 hours; unoperated rats served as controls. Two other groups, with and without in vivo treatment with LPS (2.5mg/kg) were constructed to measure postoperative jejunal muscle function by a standard organ bath technique (p<0.05). Intestinal manipulation lead to early uptake of spheres into mesenteric lymph (³0.5 hours after surgery), which was not observed in controls. A time dependent significant increase in fluorescent microsphere laded, extravasating LFA-1+ monocytes was observed within the intestinal muscularis (0±0, 0.003±0.0002 and 0.008±0.0004 Lux/200x field for 1, 12 and 24 hrs, respectively). Lymphatic ligation abolished monocytes containing spheres within the muscularis. Immunohistochemistry and electron microscopy of paramagnetic beads identified the phagocytes as ED1+ monocytes and demonstrated the systemic dissemination of phagocytes in spleen and liver Kupfer cells of manipulated animals. The functional significance of systemic bacterial products (LPS) was shown by the postsurgical suppression in bethanechol stimulated jejunal muscle contractility (0.17±0.021 vs. 0.12±0.014 gr./sec; without and with LPS, respectively). These data show that surgical manipulation of the gut leads to the lumenolymphatic transference of bacterial toxins and their uptake by circulating activated monocytes that extravasate into the intestinal muscularis.

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