Date of Award

Spring 2019

Document Type

Thesis

Publisher

Santa Clara : Santa Clara University, 2019

Department

Bioengineering

First Advisor

Jonathan Zhang

Second Advisor

Guo-Zhong Tao

Abstract

Necrotizing enterocolitis (NEC) is a disease that predominantly affects preterm infants. Of the 10% of preterm neonates that develop NEC, about one in four cases results in death. The pathophysiology presents as inflammation of intestinal epithelial cell lining and subsequent tissue death, sometimes resulting in intestinal perforations. The underlying mechanisms have yet to be comprehensively identified. Diagnosis--the rate limiting step in reducing critical disease-onset-to-treatment time--is based on relatively nonspecific signs, impeding early and accurate diagnosis. This project, a collaborative effort between Santa Clara and Stanford Universities, aims to improve current diagnostic methods by identifying the first verifiable and useful fecal biomarker for NEC. The primary molecule of interest is referenced as “Candidate-X” to protect intellectual property. Stool samples from healthy and NEC-affected infants at Stanford’s hospital, taken before and after treatment and analyzed at UC Davis, showed a strong correlation between elevated Candidate-X levels and NEC. The effects of Candidate-X and several other molecules on cell morphology were first studied in well plates seeded with either human intestinal epithelial cells (HIEC-6) or human colon cancer cells (HT-29). After HT-29 was verified as a biologically relevant cell line, two bacteria-related factors of interest, butyrate and Candidate-X, were plated with HT-29 for further study. In light of recent publications and unpublished data, Candidate-X was ultimately selected. Key results show that Candidate-X causes a comparatively high level of cell death and its effects are cell-correlated, suggesting a causative relationship between Candidate-X and NEC. Morphological changes with Candidate-X treatment reveal an unidentified cell death pathway, which will be the topic of future exploration. This paper proposes that using Candidate-X as a noninvasive fecal biomarker in combination with current methods and predictive models may improve speed and accuracy of NEC diagnosis, and outlines potential future directions for research.

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