Redefining the properties of an osmotic agent in an intestinal-specific preservation solution.

AIM: To investigate the effects of dextrans of various molecular weights (Mw) during a 12 h cold storage time-course on energetics, histology and mucosal infiltration of fluorescein isothiocyanate (FITC)-dextran. METHODS: Rodent intestines were isolated and received a standard University of Wisconsin vascular flush followed by intraluminal administration of a nutrient-rich preservation solution containing dextrans of varying Mw: Group D1, 73 kdal; Group D2, 276 kdal; Group D3, 534 kdal; Group D4, 1185 kdal; Group D5, 2400 kdal. RESULTS: Using FITC-labeled dextrans, fluorescent micrographs demonstrated varying degrees of mucosal infiltration; lower Mw (groups D1-D3: 73-534 kdal) dextrans penetrated the mucosa as early as 2 h, whereas the largest dextran (D5: 2400 kdal) remained captive within the lumen and exhibited no permeability even after 12 h. After 12 h, median injury grades ranged from 6.5 to 7.5 in groups D1-D4 (73-1185 kdal) representing injury of the regenerative cryptal regions and submucosa; this was in contrast to group D5 (2400 kdal) which exhibited villus denudation (with intact crypts) corresponding to a median injury grade of 4 (P < 0.05). Analysis of tissue energetics reflected a strong positive correlation between Mw and adenosine triphosphate (r(2) = 0.809), total adenylates (r(2) = 0.865) and energy charge (r(2) = 0.667). CONCLUSION: Our data indicate that dextrans of Mw > 2400 kdal act as true impermeant agents during 12 h ischemic storage when incorporated into an intraluminal preservation solution.

Optimizing the concentration of hydroxyethylstarch in a novel intestinal-specific preservation solution.

INTRODUCTION: Our lab has developed an effective nutrient-rich solution that facilitates energy production and control of oxidative stress during static cold storage of the intestine; however, the requirement for oncotic agents, such as hydroxyethylstarch (HES), has not been evaluated. This study investigated the effectiveness and requirement for HES in an intraluminal preservation solution during a clinically relevant period of cold storage. METHODS: Rat intestines were procured, including an intravascular flush with University of Wisconsin solution followed by a 'back table' intraluminal flush with a nutrient-rich preservation solution containing varying amounts of HES (n=6 per group): Group 1, 0%; Group 2, 2.5%; Group 3, 5%; Group 4, 10%. Energetics, oxidative stress, and morphology were assessed over a 24h time-course of cold storage. RESULTS: Overall, the 5% HES solution, Group 3, demonstrated superior energetic status (ATP and total adenylates) compared to all groups, P<0.05. Malondialdehyde levels indicated a reduction in oxidative stress in Groups 3 and 4 (P<0.05). After 12h, median modified Parks' grades for Groups 2 and 3 were significantly lower than Groups 1 and 4, P<0.05. CONCLUSION: Our data suggests that when employing an intraluminal preservation solution for static organ storage, oncotic support is a fundamental requirement; 5% HES is optimal.