3D Bioengineered In Vitro Models to Study Inflammatory Bowel Diseases
Roh, Terrence.
2021
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Thesis
(Ph.D.)--Tufts University, 2021.
Submitted to the Dept. of Biomedical Engineering.
Advisor: David Kaplan.
Committee: Madeleine Oudin, Jatin Roper, and Mark Donowitz.
Keywords: Biomedical engineering, Immunology, and Materials Science.
Animal models have delivered critical insights into mechanisms underlying the intestinal innate immune ... read moresystem; however, inherent differences exist between human and animal systems. To further understand the intestine innate immune system, there is a growing need for in vitro tissue model systems using human cells. Where mouse models for the study of intestinal innate immune systems fall short, developments from in vitro models continue to grow in importance to aid efforts to understand this system in the context of disease and potential treatments.In this work, an in vitro model of intestinal epithelium with an immune component was bioengineered to mimic immunologic responses seen in inflammatory bowel disease. 3D tissue models improve physiological relevance by providing a 3D substrate which enable migration of macrophages towards the epithelium. An intestinal epithelial layer comprised of non-transformed human colon organoid cells and a subepithelial layer laden with monocyte-derived macrophages was bioengineered to mimic native intestinal mucosa cell organization using spongy biomaterial scaffolds. Confluent monolayers with microvilli, a mucus layer, and infiltration of macrophages to the basal side of the epithelium were observed. Inflammation, induced by TLR4 ligands and interferon γ resulted in morphological changes to the epithelium, resulting in ball-like structures, decreased epithelial coverage, and increased migration of macrophages to the epithelium. Analysis of cytokines present in the inflamed tissue model demonstrated significantly upregulated secretion of pro-inflammatory cytokines that are often associated with active inflammatory bowel disease. To further enhance in vitro modeling capabilities for inflammatory bowel disease, a perfusion bioreactor system was designed and constructed for intestinal 3D tissue models. Perfusion of the 3D tissue imparts additional physiological relevance by imparting shear stress on epithelial cells while also further compartmentalizing cell populations. Using this novel system, the contributions of intestinal myofibroblasts and macrophages on intestinal inflammation which included extracellular matrix degradation and pro-inflammatory cytokine secretion was observed. The utility of this model was explored further by testing how anti-inflammatory therapeutics absolve in vitro inflammatory phenotypes. This new tissue system may be useful to study and develop potential therapies for inflammatory bowel disease.read less - ID:
- kw52jp05f
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