BACKGROUND AND AIMS: Most patients with Crohn's disease (CD) who have undergone ileocolonic resection experience recurrent inflammation within 1 year after surgery. We examined the molecular basis underlying gastrointestinal inflammation in postoperative CD across 3 common anatomic locations of recurrence.

METHODS: To characterize spatial transcriptomic signatures, this study utilized biopsies from the colon, neo-terminal ileum, and anastomosis of patients with postoperative CD in the PREDICT-OR study. Sample analyses were performed with 10X Genomics Visium CytAssist system V2.0, and data analyses with R.

RESULTS: Histologically inflamed biopsies from all locations shared transcriptional signatures across 3 cellular niches (myeloid, B, T cells) and a specialized epithelial cell type expressing inflammation-associated genes. Differentially expressed genes overexpressed inflammatory pathway activity across the 3 locations, whereas hypoxic pathways were less apparent. In addition to genes for known treatment targets, epidermal growth factor receptor and mitogen-activated protein kinase pathways were upregulated. Cellular niches shaped inflammatory microenvironments through endoplasmic reticulum stress and extracellular matrix remodeling signaling.

CONCLUSIONS: Application of spatial transcriptomics revealed a common disease signature for postoperative CD across the colon, neo-terminal ileum, and anastomosis. Inflamed biopsies from all locations demonstrated similar immune cell and inflammatory gene expression patterns as opposed to hypoxic pathways, and unique inflammatory pathways were revealed.