Specific Neuropeptide Expression in Crohn's Disease Ileocolonic Resection Specimens Is Not Associated with Plexitis at the Ileal Margin or Postoperative Recurrence

BACKGROUND

Myenteric plexitis is considered a risk factor for postoperative recurrence (POR) in Crohn's disease (CD). The primary purpose of this study was to evaluate the association between neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), and substance P (SP) expression and plexitis at the proximal resection margin. The secondary aim was to identify risk factors for POR.

METHODS

A retrospective, single-center study on CD patients who underwent ileocolonic resection (ICR) between January 2010 and December 2016 was conducted. The presence and severity of plexitis were evaluated by hematoxylin and eosin stain. Mast cells were highlighted by Giemsa stain. Immunohistochemistry was used to identify T lymphocytes and NPY-, VIP-, and SP-ergic neurons. Neuropeptide expression was quantified using image analysis.

RESULTS

Seventy-nine patients were included. No association was detected between NPY, VIP, and SP expression and plexitis. Similarly, the number of involved inflammatory cells, T lymphocytes or mast cells was not correlated with neuropeptide expression. Smoking (hazard ratio [HR] 4.07; 95% confidence interval [CI] 2.08-7.94; p < 0.001), moderate (HR 3.68; 95%CI 1.06-12.73; p = 0.040), and severe myenteric plexitis (HR 7.36; 95%CI 1.12-48.30; p = 0.037) were independent risk factors for endoscopic POR, whereas smoking (HR 2.78; 95%CI 1.01-7.67; p = 0.049), severe myenteric plexitis (HR 20.03; 95%CI 1.09-368.28; p = 0.044), and involved ileal margin (HR 3.45; 95%CI 1.33-8.96; p = 0.011) for clinical POR.

CONCLUSIONS

Smoking, moderate or severe myenteric plexitis, and involved ileal margin negatively affect POR in CD patients undergoing ICR. Submucosal and myenteric plexitis at the proximal resection margin is not related to the expression of specific neuropeptides.