P430 Prognostic significance of neuropeptide expression in ileal neural plexuses in Crohn’s disease. A retrospective study

Background Intestinal resection in Crohn’s disease (CD) is not curative and the risk for postoperative recurrence (POR) remains high. Highlighting risk factors for POR is crucial for the postoperative management of CD patients. Myenteric plexitis is a well-established risk factors for POR. The primary purpose of this study was to evaluate the correlation of neuropeptide P (NPY)-, vasoactive intestinal peptide (VIP)- and substance P (SP)-ergic nerve density with the presence and severity of plexitis in myenteric and submucosal plexuses in the proximal resection margin. Secondary aims were to assess the value of abovementioned neuropeptides’ expression in predicting POR and to recognize additional risk factors. Methods We conducted a retrospective, single-center study on CD patients who underwent ileocolonic resection (ICR) between January 2010 and December 2016. Exclusion criteria were age <16 years, patients with missing or invalid data precluding analysis, the presence of a diverting ileostomy on enrollment and specimens inappropriate for the evaluation of histologic features of interest in the proximal resection margin. Demographic and clinical data were retrieved, and the incidence or endoscopic, clinical and surgical POR was recorded. The presence and severity of plexitis was evaluated by hematoxylin and eosin staining. Giemsa staining was used for the recognition of mast cells. Immunohistochemistry was used was used for the detection of T-lymphocytes and NPY-, VIP- and SP-ergic neurons. The expression of the above peptides was quantified using image analysis. Results Seventy-nine patients (44 males) with a median age of 35 years were included. The median follow-up was 71 months. Myenteric and submucosal plexitis were present in 83.5% and 73.4% of patients, respectively. No association was detected between the density of NPY, VIP and SP expression and the presence or severity of plexitis. Similarly, the number of the involved T-lymphocytes or mast cells was not correlated with the expression of these peptides. Univariate and multivariate Cox proportional regression analysis was performed for the detection of risk factors for POR. Smoking and moderate/severe myenteric plexitis were independent risk factors for endoscopic and clinical POR, whereas an involved ileal margin was recognized as a risk factor for clinical POR. Conclusion This study did not document a correlation between plexitis in proximal resection margin and the expression of specific neuropeptides. According to our findings, smoking, myenteric plexitis, and involved ileal margin are independent risk factors for POR.