Integrity and metabolism of human ileal mucosa in vitro in the Ussing chamber

Abstract

The Ussing chamber is increasingly being used for in vitro studies of human intestinal mucosa, but little attention has been paid to the viability of specimens over time. Ninety-one mucosal specimens from the ileum in 19 patients operated on for colonic cancer were studied in regard to intestinal barrier function, metabolism, electrophysiology and histology during 360 min of incubation in Ussing chambers. Steady-state permeability to 51Cr-EDTA was maintained for 120 min. Mucosal ATP and lactate levels were stable for 180 min and transmucosal glucose flux for 240 min. Lactate dehydrogenase leakage was limited within 120 min. Transepithelial potential difference was 9.0 +/- 3.0 mV at the start, and declined slowly throughout 360 min. Light microscopy revealed epithelial lifting from the basal lamina at 90 min. Transmission electron microscopy demonstrated preserved ultrastructure for 120 min. Specimens with a transepithelial potential difference below 6 mV at the start were associated with increased 51Cr-EDTA permeability and lactate dehydrogenase leakage and more pronounced light microscopy changes. All studied parameters pointed to preserved viability if experiments were kept within a period of 90 min after equilibration. The few specimens with early viability derangement were identified by a transepithelial potential difference below 6 mV at the start. The Ussing chamber provides a tool for in vitro studies of human intestinal epithelium, including permeability. To minimize viability problems, experiments should be limited in time and monitored by measurements of transepithelial potential difference.

In Vitro Diffusion Barriers of the Mouse Jejunum in Ussing Chambers

“…They have also shown that the permeability of the water-soluble substance mannitol was time-dependently increased, although only by a small degree. The human ileum incubated in Ussing chambers for more than 2 h has reportedly shown that the permeability to 51 Cr-EDTA (Mr 360) was increased in parallel with epithelial lifting and sloughing, although the magnitude of the increase was moderate (14). These reports support our proposal that the subepithelial lamina propria/submucosa of the small intestine constitute a non-epithelial diffusion barrier to water-soluble molecules (including NaCl).…”

Characterization of antigen and bacterial transport in the follicle-associated epithelium of human ileum

“…A four electrode system was used as previously described. 20 One pair of Ag/ Ag-electrodes (Ref 201, Radiometer, Copenhagen, Denmark) with 3 M NaCl/2% agar bridges was used for measurements of PD and one pair of platinum electrodes for current passage. Transepithelial potential difference, Isc and TER were obtained as described by Karlsson et al 21 The electrodes were coupled to an external six channel electronic unit with a voltage controlled current source.…”

Salmonella enterica serovar Choleraesuis infection of the porcine jejunal Peyer's patch rapidly induces IL-1β and IL-8 expression

“…In previous studies of human intestinal mucosa maintained in Ussing chambers, I sc and G t were stable for at least 2 h and the epithelial surface remained histologically intact for at least 2.5 h (Larsen et al, 2001;Soderholm et al, 1998). Because epithelial degradation and edema occur after several hours of incubation (Figure 2 and (Larsen et al, 2001;Soderholm et al, 1998), experiments in the Ussing chamber were limited to 2 to 3 h. Glucose-stimulated Na + absorption at the end of the incubation period demonstrated that the JPP was functionally intact (Larsen et al, 2001).…”