PROJECT SUMMARY AND ABSTRACT
Inflammatory bowel diseases (IBD), comprising Crohn's disease (CD) and ulcerative colitis (UC), are chronic,
progressive, inflammatory conditions of the gastrointestinal tract that affect up to 3 million Americans. IBD is
thought to be driven by inappropriate immune responses to an altered gut microbiome, or dysbiosis, with a
disease course characterized by remitting and relapsing episodes of inflammation, or flares. Despite increasing
knowledge regarding the relationship between the gut microbiome, dysbiosis, and the impact on mucosal
immunity, much remains unknown regarding the inciting environmental factors and underlying mechanisms
that result in intestinal inflammation. In addition, although there have been dramatic improvements in IBD
therapeutics, the disease course has remained relatively unchanged with patients remaining at high risk for
recurrent flares, complications, surgeries, and reduced quality of life. Enteric infections are a common cause of
dysbiosis, and have been implicated as an environmental factor in onset and flare of IBD. Our preliminary data
has identified enteric infection in nearly 30% of IBD flares, with the most common pathogens including
Clostridioides difficile, Enteropathogenic Escherichia coli (EPEC), and norovirus. This K23 proposal will
address this knowledge gap by testing the hypothesis that enteric infection is a major environmental factor in
flare of IBD, producing a specific subtype of flare characterized by a unique clinical presentation and impact on
IBD progression, distinct from patients with a flare but without an enteric infection. To test this hypothesis, we
will recruit and prospectively follow patients with flare of IBD with the presence of C. difficile, EPEC, or
norovirus, and separately with flare of IBD but without a gastrointestinal pathogen. We will identify the clinical
(Aim 1), gut microbiome, and immune factors (Aim 2) that distinguish flares complicated by enteric infection to
directly improve IBD outcomes in these patients. This will be the first study to longitudinally determine the
clinical and molecular impact of specific enteric pathogens on the course of IBD with the potential to reveal
innovative mechanisms regarding the role of enteric pathogens as environmental factors in IBD, and novel
approaches to the management of this complex clinical scenario. To conduct this research, further training is
required, and Dr. Axelrad has assembled a multidisciplinary team of mentors to provide detailed training in
immunology and microbiology, biostatistics and quantitative methods, and funding and grantsmanship. This
K23 proposal will position Dr. Axelrad to accomplish the goal of determining the role of specific enteric
pathogens in flares of IBD and facilitate his development into an independent, patient-oriented and
translational investigator in the field of IBD.