M. R. Ladd1, C. Costello2, B. Johnson1, C. Gosztyla1, A. Werts1, L. Martin1, W. Fulton1, P. Lu1, H. Jia1, E. Banfield1, J. Sung1, S. Wang1, T. Prindle1, Y. Yamaguchi1, C. Sodhi1, J. C. March2, D. J. Hackam1 1Johns Hopkins University School Of Medicine,General Surgery,Baltimore, MD, USA 2Cornell University,Ithaca, NY, USA
Introduction: Short bowel syndrome is a devastating disease with limited treatment options. The development of an artificial intestine offers a potential solution, however, the ability to develop functional small intestine has been limited in part due to scaffolds with inadequate mechanical properties to promote intact intestinal tissue formation. The goal of this study is to develop and evaluate intestinal-like scaffolds that mimic the mechanical properties of native small intestine and thus to cross a technical hurdle in the generation of an artificial intestine.
Methods: Intestinal-like scaffolds were fabricated from poly(glycerolsebacate) using a serial fabrication technique with laser indentation into agarose gel to create microvilli that mimic the height and width of native intestinal villi. The pore size and crosslinker were varied from the villus portion to the basal portion to further approximate the native bowel. We evaluated the tensile properties of these synthetic scaffolds (n=10, in triplicate) and compared them to porcine intestine from 3-week-old piglets (n=9, in triplicate). The in vitro degradation of the scaffolds in media and media plus digestive enzymes (to mimic the intestinal environment) was characterized by mass loss (n=3 per condition) and scanning electron microscopy. Scaffolds were coated with matrigel and seeded with murine intestinal stem cell cultures (n=3) harvested to evaluate for cell attachment. Young's modulus, a measure of stiffness, was calculated as the slope of the linear portion of each stress-strain curve.
Results: Our novel scaffolds demonstrated projections which approximated villi seen in intestine. The Young’s modulus of the scaffolds was 5.6 MPa vs. 1.03 MPa for small intestine. The ultimate tensile strength and maximum load of the scaffolds were 1.45 MPa and 3.2 N compared to 1.11 MPa and 1.3 N for the small intestine. Strain at failure was higher in the intestine (175% vs. 77%). In vitro degradation studies demonstrated 42% mass loss at 5 weeks yet the villus structures were still present, consistent with that seen in the native mammalian state. When seeded with murine intestinal stem cells, the scaffolds demonstrated good cell attachment by confocal microscopy and scanning electron microscopy (SEM).
Conclusion: We have successfully developed synthetic scaffolds with mechanical properties that approximate those of native piglet small intestine and allow for attachment of stem cells suggesting they may be suitable for tissue engineered small intestine.
