title: Surgical manipulation of the gut elicits an intestinal muscularis inflammatory response resulting in postsurgical ileus.
abstract: OBJECTIVE
  To investigate the pathophysiologic mechanisms that lead to ileus after abdominal surgery.
  
  
  BACKGROUND
  The common supposition is that more invasive operations are associated with a more extensive ileus. The cellular mechanisms of postsurgical ileus remain elusive, and few studies have addressed the mechanisms.
  
  
  METHODS
  Rats were subjected to incremental degrees of surgical manipulation: laparotomy, eventration, "running," and compression of the bowel. On postsurgical days 1 and 7, muscularis infiltrates were characterized immunohistochemically. Circular muscle activity was assessed using mechanical and intracellular recording techniques in vitro.
  
  
  RESULTS
  Surgical manipulation caused an increase in resident phagocytes that stained for the activation marker lymphocyte function-associated antigen (LFA-1). Incremental degrees of manipulation also caused a progressive increase in neutrophil infiltration and a decrease in bethanechol-stimulated contractions. Compression also caused an increase in other leukocytes: macrophages, monocytes, dendritic cells, T cells, natural killer cells, and mast cells.
  
  
  CONCLUSIONS
  The data support the hypothesis that the degree of gut paralysis to cholinergic stimulation is directly proportional to the degree of trauma, the activation of resident gut muscularis phagocytes, and the extent of cellular infiltration. Therefore, postsurgical ileus may be a result of an inflammatory response to minimal trauma in which the resident macrophages, activated by physical forces, set an inflammatory response into motion, leading to muscle dysfunction.
authors.affiliation: Department of Surgery, University of Pittsburgh Medical Center, Pennsylvania, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Kalff
authors.forename: W H
authors.initials: WH
authors.lastname: Schraut
authors.forename: R L
authors.initials: RL
authors.lastname: Simmons
authors.forename: A J
authors.initials: AJ
authors.lastname: Bauer
mesh_terms: D000818:Animals; D006651:Histocytochemistry; D007150:Immunohistochemistry; D007249:Inflammation / Q000209:etiology; D007415:Intestinal Obstruction / Q000209:etiology*; D007583:Jejunum / Q000473:pathology / Q000601:surgery*; D008297:Male; D009130:Muscle, Smooth / Q000473:pathology / Q000601:surgery*; D011183:Postoperative Complications / Q000209:etiology*; D051381:Rats; D011912:Rats, Inbred ACI