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