Inflammatory bowel disease (IBD), consisting of two major forms, Crohn's disease (CD) and ulcerative colitis, affects more than 1.6 million people in the United States alone. Despite current therapies, remission only occurs in approximately half of patients. The goal of study is to map single-cell spatial relationships across the spectrum of ileum/ascending colon from healthy control patients to uninvolved/quiescent and involved/active CD patients and assess for relationships between single-cell data and patient clinical data.

The investigators will utilize endoscopic mucosal biopsies and surgical resection specimens with rapid transfer of fresh tissue to the single-cell preparation for RNA-sequencing and use of tissues for RNA-fluorescence in situ hybridization and multiplex immunofluorescence. Along with machine learning image analysis and bioinformatics, this will generate a robust/detailed single-cell gut cell atlas (GCA) of ileo-colonic CD at all disease activities versus normal tissues. The study will also compare the results of endoscopic mucosal biopsies to those obtained from full thickness surgical specimens by utilizing the Cooperative Human Tissue Network (CHTN).

The investigators anticipate the GCA data will provide new insights into disease pathogenesis, leading to new therapeutic targets.

Inclusion criteria:

• Provision of consent form
• Male or female greater than or equal to 18 years old
• Healthy volunteers without IBD undergoing colonoscopy for colorectal cancer screening or patients with a diagnosis of Crohn's disease (CD) confirmed by endoscopy or radiology assessment undergoing colonoscopy for clinical care

Exclusion criteria:

• Pregnancy
• Coagulopathy or bleeding disorder
• Renal or hepatic impairment
• History of organ transplantation

Patients undergoing standard of care colonoscopy procedure at Vanderbilt University Medical Center (VUMC) and/or receiving care at the VUMC Inflammatory Bowel Disease Clinic.

The investigators agree to the timely release and sharing of information to be no later than the acceptance for publication of the main findings from the final data set. Investigators are also committed to ensuring that all data are free of identifiers that would permit linkage to individual research participants as well as variables that could lead to deductive disclosure of the identity of individual subjects.