Oxidation status as a predictor of disease activity and response to therapy in pediatric patients with inflammatory bowel disease
Weinbren, Nathan Leo
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INTRODUCTION: Physiologic and pathophysiologic inflammation is mediated, at least in part, by the generation and release of reactive oxygen species into the local tissue milieu. The chronic inflammation observed in patients with inflammatory bowel disease (IBD) is thought to begin in the lining of the intestine and may progress to involve the entire bowel wall.In an effort to assess disease activity, clinicians rely on costly and technically invasive procedures such as colonoscopies. As such, there is currently a need for the development of less invasive and more cost-effective methods for use in the diagnosis and interval assessment of children and adults with these chronic intestinal inflammatory disorders. OBJECTIVES: The objective of this study was to first determine if ambient redox status can be reliably measured in the stool of patients with IBD. A second aim of the study was to determine if ambient stool redox status was related to underlying diagnosis, clinical disease activity, or response to therapy in patients with IBD . METHODS: We first our ability to measure redox redox standards using three different commercially available devices. Once demonstrated, we then the process of performing sample analysis under various conditions (room tempererture, refrigerated, frozen, or spun/unspun) to determine the conditions under which we were able to achieve the most stable redox assessments. Finally, we conducted a small pilot cohort study in hospitalized pediatric patients with IBD to assess if stool redox status informed about disease activityWe collected stool samples from seven patients admitted to the inpatient gastrointestinal service at Boston Children’s Hospital during a period extending from November of 2018 to March of 2019. RESULTS: Preliminary studies confirmed our ability to accurately measure relative redox status (RRS) using three different apparatuses. Furthermore, we were able to generate dilution curves using juices known to include oxidants, with linear regression r2 values of 0.99. In our patient population, we confirmed our ability to generate a reliable readings and consistent RRS measurements over. Frozen samples displayed less stable and higher RRS than those either refrigerated or kept at room temperature for up to 8-hours. This suggests that freeze-thaw cycles may impact adversely on the stability of oxidants and antioxidants in our samples. The RRS measurements from stool samples collected from patients who were exhibiting active symptoms of their IBD measured about -400 mV, while samples collected from hospitalized patients without IBD manifest RRS readings of about 100 mV. CONCLUSION: This preliminary study demonstrates our ability to measure RRS in the stool of patients with and without IBD. The stability we observed in samples that were either stored at room temperature or refrigerated demonstrated that these represented optimal storage options. Additionally, measurements from homogenized stool samples appeared to be more variable when compared to the relatively smaller range from centrifuged samples. Initial studies indicated a strong difference in RRS measurements between patients with inflammatory and non-inflammatory GI disease or inactive IBD. This difference suggests that measurements of RRS could provide a quantitative real-time assessments of disease activity and response to therapy in patients with IBD.