Neurotransmitter coding of enteric neurones in the submucous plexus is changed in non-inflamed rectum of patients with Crohn's disease

Knowledge of the neurochemical coding of submucosal neurones in the human g ut is important to assess neuronal changes under pathological conditions. W e therefore investigated transmitter colocalization patterns in rectal subm ucosal neurones in normal tissue (n=11) and in noninflamed tissue of Crohn' s disease (CD) patients (n=17). Neurone-specific enolase (NSE), choline ace tyltransferase (ChAT), vasoactive intestinal polypeptide (VIP), substance P (SP), nitric oxide synthase (NOS) and calcitonin gene-related peptide (CGR P) were detected immunohistochemically in whole-mount preparations from rec tal biopsies. The neuronal marker NSE revealed no differences in the number of cells per ganglion (controls 5.0; CD 5.1). Four cell populations with d istinct neurochemical codes were identified. The sizes of the populations C hAT/VIP (58% vs. 55%), ChAT/SP (8% vs. 8%), and ChAT/- (22% vs. 22%) were s imilar in control and CD. The population VIP/- was significantly increased in CD (12% vs. 2% in controls). Unlike in controls, all NOS neurones coloca lized ChAT in CD. Thickened CGRP-fibres occurred in CD. We identified neuro chemically distinct populations in the human submucous plexus. The increase in the VIP/- population, extensive colocalization of ChAT and NOS and hype rtrophied CGRP fibres indicated adaptive changes in the enteric nervous sys tem in noninflamed rectum of CD patients.