Direct activation of human peritoneal mesothelial cells by heat-killed microorganisms

Ann Surg. 1996 Dec;224(6):749-54; discussion 754-5. doi: 10.1097/00000658-199612000-00010.


Objective: The aim of the study was to determine if human peritoneal mesothelial cells (HPMCs) can be activated directly by bacterial products contained in preparations of heat-killed Escherichia coli and staphylococci.

Summary background data: It has been shown recently that cytokine-activated HPMCs produce the inflammatory mediators, interleukin-1, interleukin-6, interleukin-8, and macrophage chemotactic protein-1. Studies concerning the effects of bacterial products on HPMCs are scarce and have not yielded conclusive results.

Methods: Growth-arrested HPMC monolayers were prepared from cell suspensions obtained by enzymatic disaggregation of small pieces of omentum. They were incubated for 24 hours with heat-killed E. coli (ATCC 25922), heat-killed staphylococci (ATCC 25933), or E. coli lipopolysaccharide, and the release of various cytokines in the culture media was measured by radioimmunoassays or enzyme-linked immunosorbent assays. Results were expressed as mean +/- standard error of the mean in picograms per milliliter of supernatant and analyzed with the Wilcoxon test; p values of less than 0.05 were considered significant.

Results: Baseline production of interleukin-6, interleukin-8, the chemokine "regulated upon activation, normal T cell expressed and secreted" (RANTES), and macrophage chemotactic protein-1 varied widely from one omental preparation to the other. E. coli increased the release of these mediators: from 1206 +/- 316 pg/mL to 8480 +/- 2189 pg/mL for interleukin-6, from 285 +/- 58 pg/mL to 3164 +/- 1053 pg/mL for interleukin-8, from 7 +/- 5 pg/mL to 684 +/- 264 pg/mL for RANTES, and from 2212 +/- 346 pg/mL to 7726 +/- 1473 pg/mL for macrophage chemotactic protein-1. Heat-killed staphylococci did not alter significantly the production of RANTES or macrophage chemotactic protein-1 but increased the production of the two other cytokines from 1325 +/- 389 pg/mL to 2206 +/- 523 pg/mL for interleukin-6 and from 318 +/- 70 pg/mL to 819 +/- 265 pg/mL for interleukin-8.

Conclusions: The authors' results show that HPMCs are able to react to a direct stimulation with heat-killed microbes. They suggest that HPMCs, as well as resident macrophages, participate actively in the initiation and possibly in the modulation of intraperitonen inflammatory reactions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chemokine CCL2 / biosynthesis*
  • Chemokine CCL5 / biosynthesis*
  • Epithelial Cells
  • Epithelium / immunology
  • Escherichia coli
  • Hot Temperature
  • Humans
  • Interferon-alpha / pharmacology
  • Interleukin-6 / biosynthesis*
  • Interleukin-8 / biosynthesis*
  • Peritoneum / cytology*
  • Peritoneum / immunology
  • Staphylococcus aureus


  • Chemokine CCL2
  • Chemokine CCL5
  • Interferon-alpha
  • Interleukin-6
  • Interleukin-8