Background, aims: The changes of different neuropeptide containing nerve elements might play a role in the pathogenesis of cholecystitis and the formation of gallstones, therefore the authors have investigated the density of the neuropeptide containing nerve fibres and immunocompetent cells in human gallbladder (control and cholecystitis).
Methods: The different neuropeptide containing nerve elements and immunocytes were detected by avidin-biotin-peroxidase (ABC) immunohistochemistry.
Results: In the control gallbladder the density of the different neuropeptide containing nerve fibres showed different pattern in all layers. In the inflamed gallbladder the number of the vasoactive intestinal polypeptide (VIP) positive nerve fibres increased significantly, very dense immunoreactive (IR) nerve fibres were located mainly in the tunica mucosa just below the epithelial lining. The number of the VIP IR nerve cell bodies was also increased. However, the number of the substance P (SP) IR nerve fibres was decreased significantly in the cholecystitis. The number of the neuropeptide Y (NPY) nerve fibres showed no changes, while their distribution was altered compared to the control. In the inflamed area the number of immunocompetent cells was strongly increased (being granulocytes, lymphocytes, plasma cells and mast cells) and some of them were also immunoreactive for SP, calcitonin gene-related peptide (CGRP) and VIP. Close contacts were detected between IR nerve fibres and the immunocytes in several cases.
Conclusions: During inflammation the changes of the neuropeptide containing nerve fibres might alter the function (causing dilation) of the gall bladder, the activated immunocytes can also synthesize neuropeptides (SP, CGRP, VIP), so the released materials (cytokines, chemokines, histamine, as well as neuropeptides) might act in an autocrine and/or paracrine way influencing the function of the organ and of the immune system.