| الوصف: |
Oesophageal adenocarcinoma originates in the gastroesophageal junction and has a poor prognosis. Barrett's oesophagus is a common, innocuous condition occurring prior to most adenocarcinoma cases. This lesion is frequent in patients suffering from gastroduodenal reflux and involves columnar cells replacing a segment of the squamous lining of the distal oesophagus. High variability in the length of the segment exists between individuals and typically patients with longer lesions have an increased risk of developing adenocarcinoma. However, the pathways promoting this replacement and determining its final length are unknown. In this thesis, I investigate models to study this phenomenon in vitro. In the first part of this thesis, I describe a system that I developed to study interactions between epithelial cell populations and apply it to combinations of cells which are crucial for Barrett's oesophagus progression. My findings indicate that squamous and early Barrett's oesophagus derived cells form stable junctions and that reflux-like epidermal growth factor concentrations can disrupt this stability. In part two, I adapt existing 3D culture methods to study heterotypic junctions in vitro. Combining oil bath and plastic printing techniques, I have constructed rings with organoid epithelial lining. I demonstrate as well that it is possible to control the ring's size via the addition of fibroblasts into the collagen. Through addition of a divider, I was able to recapitulate heterotypic junctions between organoid populations and, by making the moulds higher, I show that it is possible to generate tube structures using the same technique. Additionally, I demonstrate that using fibroblast gradients in the tubes can control their shape. Building upon the contractibility of the fibroblasts, I also show that adaptors can be fixed at the ends of the tubes to control flow through it. Using this system, I am able to coat the tube's lumen with epithelia and infect the cells with pathogens to recapitulate a more natural infection. Lastly, I generated an endoscopic mucosal resection biobank for microdissection with the samples being annotated with the assistance of pathologists. I then validated this system by micro-dissecting three candidate patients. |
