Role of Bacterial Adherence and the Mucus Barrier on... : Annals of Surgery (original) (raw)

Advances in Surgical Technique: Original Articles

Effects of Protein Malnutrition and Endotoxin in Rats

Katayama, Masami M.D.*; Xu, Dazhong M.D.*; Specian, Robert D. Ph.D.†; Deitch, Edwin A. M.D.*

From the Department of Surgery,* University of Medicine and Dentistry of New Jersey, Newark, New Jersey, and the Department of Cellular Biology and Anatomy,† Louisiana State University Medical Center, Shreveport, Louisiana

Address reprint requests to Edwin A. Deitch, M.D., Department of Surgery MSB G506, UMD-NJ New Jersey Medical School, 185 S. Orange Avenue, Newark NJ 07103-2714.

Accepted for publication March 6, 1996.

Supported by NIH grant GM 48131 (EAD) and DK 38720 (RDS).

Abstract

Objective

The purpose of the study was to investigate the potential relations between mucosal bacterial adherence, intestinal mucus and mucin content, and bacterial translocation.

Summary Background Data

The attachment of bacteria to mucosal surfaces is the initial event in the pathogenesis of most bacterial infections that originate at mucosal surfaces, such as the gut. The intestinal mucus layer appears to function as a defensive barrier limiting micro-organisms present in the intestinal lumen from colonizing enterocytes. Consequently, studies focusing on the biology of bacterial adherence to the intestinal mucosa likely are to be important in clarifying the pathogenesis of gut origin sepsis.

Methods

To explore the relations between intestinal bacterial adherence, mucus bacterial binding, and bacterial translocation, two models were used. One (protein malnutrition) in which profound alterations in intestinal morphology occurs in the absence of significant translocation and one (endotoxin challenge) in which bacterial translocation occurs and intestinal morphology is relatively normal.

Results

Protein malnutrition was not associated with bacterial translocation and measurement of enteroadherent, mucosally associated bacterial population levels documented that the total number of gram-negative enteric bacilli adherent to the ileum and cecum was less in the protein-malnourished rats than in the normally nourished animals (p < 0.01). Furthermore, there was an inverse relation between the duration of protein malnutrition and bacterial adherence to the intestinal mucosa (r = 0.62, p < 0.002). In contrast, after endotoxin challenge, the level of enteroadherent bacteria was increased and bacterial translocation was observed. The binding of Escherichia coli to immobilized ileal mucus in vitro was decreased significantly in protein-malnourished rats, whereas E. coli binding to insoluble ileal mucus was increased in the rats receiving endotoxin.

Conclusions

This study indicates that the adherence of bacteria to the intestinal mucosal surface is an important factor in bacterial translocation, that intestinal mucus modulates bacterial adherence, and that increased levels of mucosally associated bacteria are associated with a loss intestinal barrier function to bacteria.