The direct comparison of health and ulcerated stomach tissue: A multiple probe microdialysis sampling approach

Abstract

The ability to directly compare gastric ulcerated and healthy tissue would aid in the understanding of the physiological differences between these tissue types. Presently, these comparisons can only be drawn by the use of separate animal groups, which results in increased study variability. The focus of this research was to develop a four-probe microdialysis sampling approach to directly compare ulcerated and healthy tissue in the same animal. After controlled chemical ulcer induction, probes were implanted in the ulcerated and healthy stomach submucosa, stomach lumen and in the blood. To assess the significance of this multiple probe approach, drug concentrations in each probe location were monitored after selected compounds were dosed to the ligated stomach by oral gavage. Analysis of the dialysate samples was performed by HPLC-UV and concentration-time curves and pharmacokinetics analyses were used to determine differences between these tissue types.

Microdialysis Monitoring of Biomarkers for Early Recognition of Intestinal Ischemia

“…This fourprobe microdialysis sampling was used to directly compare drug absorption between gastric ulcerated and healthy tissue in the same animal, where the dialysate was analysed using high performance liquid chromatography ultraviolet (HPLC-UV). The study showed a higher drug concentration in ulcer tissue, which was a function of ulcer size and thickness and probe location within the tissues when compared to healthy tissue (112). The reconstructed oesophagus of patients undergoing resection of carcinoma was monitored with microdialysis to investigate the risk of postoperative complications caused by ischemia.…”

Analytical Considerations for Microdialysis Sampling

“…Later, the same group demonstrated the use of a linear probe for transdermal delivery studies [25,181] . This same probe design was then widely utilized for studies of various tissues, including liver [182] , tumor [183] , stomach [10,11] , and muscle [184] .…”

“…By 2007, microdialysis had evolved enough as a tool for pharmacokinetic and drug metabolism studies that the U.S. Food and Drug Administration sponsored a workshop on the role of microdialysis in the drug evaluation process [41] . Recently, Woo and Lunte used multiple probes to monitor the absorption of caffeine by a healthy versus ulcerated stomach in a rat model [10,11] . Figure 19 shows the average caffeine concentration in the blood and in ulcerated and healthy stomach tissue following an oral dose of caffeine.…”

“…This technique has been employed extensively for pharmacokinetic and pharmacodynamic studies as well as for drug delivery. Microdialysis has been used to monitor drugs and other biologically important compounds in virtually every tissue and organ in the body, including liver [1,2] , heart [3,4] , skin [5,6] , blood [7,8] , placenta [9] , stomach [10,11] , ear [12] , and brain [13,14] .…”

“…Plot of the average caffeine concentration in the lumen (fi lled squares), in the submucosa of ulcerated (empty triangles), and in blood (empty circles) determined by microdialysis sampling as a function of time following a 5 mM oral dose to the ulcerated stomach. (From[10] .…”