Introduction: Our lab has developed a novel strategy for intestinal preservation involving the intraluminal delivery of a nutrient-rich preservation solution. The aim of this study was to compare the effectiveness of two impermeant agents for use in our solution: Dextran 70 (D70; Mw = 70. kDa) and Hydroxyethyl starch (HES; Mw = 2200. kDa). Methods: Rat intestines were procured, including an intravascular flush with University of Wisconsin solution followed by a 'backtable' intraluminal flush with: UW solution (group 1, UW), or an amino acid-based nutrient-rich preservation solution (AA solution) containing either 5% D70 (group 2, AA-D70) or HES (group 3, AA-HES). Tissue samples ( n= 6) were taken at 2, 4, 8, and 12. h cold storage; histology, energetic, end-product, and oxidative parameters were assessed. In separate groups ( n= 4), D70 and HES were fluorescently labeled with fluorescein isothiocyanate (FITC) in order to directly observe mucosal penetration of the starch and dextran. Results: Over the 12. h storage time-course, direct visualization of the fluorescently labeled D70 showed penetration of the mucosal layer as early as 2. h and progressively continued to do so throughout the 12. h period. In contrast, HES did not cross the mucosal barrier and remained captive within the lumen. As time of storage progressed, grade of injury increased in all groups, however, at 4 and 12. h the AA-HES treated tissues exhibited significantly less injury compared to UW and AA-D70,. P< 0.05. AA-HES group showed on moderate villus clefting (median grade 2 P< 0.05) while the AA-D70 group exhibited complete villus denudation (grade 4) and the UW group had extensive injury into the regenerative cryptal regions (grade 6). Metabolic parameters revealed a preferential maintenance of ATP and Energy Charge; increases in lactate, alanine and ammonium supported the involvement of aerobic and anaerobic pathways for energy production. Conclusion: The results of this study challenge the idea that oncotic support is not a fundamental requirement of static organ storage. Furthermore, our data suggests that HES is an effective oncotic agent for use in our intraluminal nutrient-rich preservation solution, while Dextran 70 is not.
- Mucosal permeability
- Organ preservation solution
- Osmotic/oncotic agents
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Agricultural and Biological Sciences(all)