M. J. Barahona1, M. Finotti1,4, J. Ollodart1, V. M. Baratta1, T. M. Gisinger1,2, G. Caturegli1,4, R. M. Maina1,4, F. D’Amico1,4, D. Mulligan1, J. P. Geibel1,3 1Yale University School Of Medicine,Department Of Surgery,New Haven, CT, USA 2Paracelsus Medical University,Department of Medicine,Salzburg, SALZBURG, Austria 3Yale University School Of Medicine,Department of Cellular and Molecular Physiology,New Haven, CT, USA 4University of Padua,Department Of Transplantation And Hepatobiliary Surgery,Padua, PADUA, Italy
Introduction: The intestine is one of the most susceptible organs to ischemia making it extremely difficult to transplant. There is a need for the development of innovative methods to preserve intestinal viability. New efforts are focused on creating particle based delivery systems in the range from 10-1000 nm, or collectively known as nanoparticles. Formulation of nutraceuticals into nanoparticles and nanocomplexes can better facilitate delivery and cellular uptake in colonic systems. Here, we examined how calcium nanoparticle perfusion targeting the Calcium Sensing Receptor (CaSR) could reduce intestinal ischemic damage in the mammalian colon.
Methods: Small intestinal segments from Sprague-Dawley male rats were obtained and perfused with an ex-vivo intestinal perfusion device. Segments were perfused with and without calcium nanoparticles in an induced ischemic environment, 100% N2 and 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), compared to small intestine segments perfused without an ischemic environment (HEPES). Fluid secretion or absorption of the intestine was measured by fluorescein isothiocyanate-inulin (FITC-Inulin). Using FITC-Inulin concentration we assessed the ischemic conditions (decreased fluorescence) of the perfusate through the intestinal grafts in real-time.
Results: Small intestinal segments exposed to 100% N2 developed a significantly greater degree of ischemic damage when compared to intestine perfused with normal HEPES buffer, p <0.0001. In this nitrogen-induced ischemic environment, the presence of 1.0 mM, 2.5 mM and 5.0 mM of calcium carbonate nanoparticles prevented the damage (increased fluid secretion, p <0.0001, Figure 1). Intestinal segments exposed to nitrogen and nanoparticles resisted ischemia to a greater extent than segments exposed to normal HEPES p <0.0001.
Conclusion: Calcium carbonate nanoparticles targeting the CaSR can mitigate ischemic damage in the small intestine. These results suggest that nanoparticles may be a novel therapeutic vector for reducing ischemic and inflammatory injury. This suggests that nanoparticle activation of CaSR would be an important prophylactic therapy to improve organ viability.
