Measurements of the jejunal unstirred layer in normal subjects and patients with celiac disease. Strocchi, Alessandra, Ginoroberto Corazza, Julie Furne, Caryn Fine, Antonio Di Sario, Giovanni Gasbarrini, Michael D Levitt. I Patologia Medica, University of Bologna, Bologna, Italy, VA Medical Center, Minneapolis, MN; and University of Minnesota, Minneapolis, MN
APStracts 2:0216G, 1995.
Normal intestinal absorption of nutrients requires efficient luminal mixing to deliver solute to the brush border. Lacking such mixing, the build-up of thick unstirred layers over the mucosa markedly retards absorption of rapidly transported compounds. Using a technique based on the kinetics of maltose hydrolysis, we measured the unstirred layer thickness of the jejunum of normal subjects and patients with celiac disease, as well that of the normal rat. The jejunum of humans and rats was perfused with varying maltose concentrations, and the apparent Km and Vmax of maltose hydrolysis were determined from double-reciprocal plots. The true Km of intestinal maltase was determined on mucosal biopsies. Unstirred layer thickness was calculated from the in vivo Vmax and apparent Km and the in vitro Km of maltase. The average unstirred layer thickness of 11 celiac patients (170 [mu]m) was seven times greater that of three controls (25 [mu]m). The unstirred layer of each celiac exceeded that of the controls. A variety of factors could account for the less efficient luminal stirring observed in celiacs. Although speculative, villous contractility could be an important stirring mechanism which would be absent in eliacs with villous atrophy. This speculation was supported by the finding of a relatively thick unstirred layer (mean: 106 [mu]m) in rats, an animal that lacks villous contractility. Since any increase in unstirred layer slows transport of rapidly absorbed compounds, poor stirring appears to represents a previously unrecognized defect that could contribute to malabsorption in celiac disease and, perhaps, in other intestinal disorders.

Received 1 March 1995; accepted in final form 13 September 1995.
APS Manuscript Number G93-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 November 95