A. O. AlKukhun1, A. Muñoz Abraham1, S. Judeeba1, C. Jasinski1, R. Patron-Lozano1, M. I. Rodriguez-Davalos1, J. P. Geibel1 1Yale University,Department Of Surgery,New Haven, CT, USA
Introduction:
Intestinal ischemia can be seen in conditions such as mesenteric ischemia, or in a challenging situation like intestinal transplantation. Intestinal ischemia leads to pathophysiological disruption that typically presents as increased fluid secretion into the lumen of the intestine with increased levels of ischemia. The aim of this study was to understand the fluid alterations that occur with intestinal ischemia, and determine if FITC-Inulin measurement is sensitive to measure the changes in fluid movement across an intact rat intestinal graft as a real-time measurement of ischemic injury.
Methods:
Male Sprague Dawley rats (average weight of 400g) were operated on in accordance with the Animal Care and Use Committee at Yale University. Two 10 cm small intestine segments were procured from the rats. The intestinal segments were cleansed with HEPES (pH: 7.40, Osmolarity 300±5 at 37°C) solution to clear remaining intestinal contents. The intestinal segments were connected to customized intestinal chambers that are part of a perfusion device. The chambers were kept in a water bath maintained at 37°C. Both intestines were perfused on the vascular side with HEPES buffer solution (pH: 7.40, Osmolarity 300±5 at 37°C). The control HEPES reservoir was open to air, while the experimental reservoir was sealed and bubbled with 100% Nitrogen (N2) to mimic an ischemic environment. Inside both lumens, 3ml of HEPES containing 50 µM FITC-Inulin was continuously perfused at a rate of 1ml/min. Intraluminal samples of the perfusates were collected at three 30 minutes’ intervals to measure FITC-Inulin concentration using a nanospectrofluorimeter.
Results:
When comparing measurements of FITC-Inulin in both intestines, there was a mean 37% reduction of FITC-Inulin concentration in the control versus a mean 57% reduction in the experimental arm, thus indicating increased fluid secretion that was stimulated by the ischemic environment. After examining and comparing the ischemic with the control tissue, an approximate doubling of the amount of secretion was observed over the same time period.
Conclusion:
FITC-Inulin can be used effectively as a volume marker that equates to the ischemic state of the intestinal tissue. This is a practical method to measure real time fluid changes inside a small intestine graft. This model can now be used to assess other intestinal ischemia models: assess viability of intestinal grafts prior to transplant, and monitor drug candidates against ischemia.
