Changes of the different neuropeptide containing nerve fibres in the inflamed human gall bladder

Background, Aims: Increasing evidence indicates that the different neuropeptide containing nerve elements are also involved in the motility of the gall bladder besides of the hormones. However no reports are available on the changes of the distribution and density of these neuropeptide containing nerve fibres in pathological conditions e.g. cholecystitis. Therefore our aim was to investigate the precise localization and density of the nerve fibres and immunocompetent cells in human cholecystitis.

Methods: Vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), substance P (SP), galanin, calcitonin gene-related peptide immunoreactive (IR) nerve elements and poly(ADP-ribose) polymerase and tumor necrosis factor 2 alfa immunocompetent cells were detected by ABC immunohistochemistry.

Results: The quantitative analysis of the density of the different neuropeptide containing nerve fibres showed that the IR nerve fibres were found with different density in all layers of the gall bladder. The total number of all of the investigated nerve fibres was decreased in all the inflamed gall bladders. Their localization was also changed, most of the NPY and VIP IR nerve fibres were located mainly in the tunica mucosa just below the epithelial lining. In the inflamed area the number of the immunocompetent cells was also increased (being lymphocytes, plasma cells and mast cells) and some of them were also IR for SP, CGRP and VIP. Close contacts were detected between IR nerve fibres and the immunocytes in several cases.

Conclusions: Changes of the IR nerve fibres in inflammation might alter the function (causing dilation) of the gall bladder and they are also involved in neuroimmunomodulation. The immune cells synthesize, store and release the above substances acting as autocrine and/or paracrine factors, contribute to regulate immune function.