Neuropeptides are able to modulate cytokine production by macrophages in response to various stimulators and have a major role in inflammation of different organs. Mammalian poly (ADP-ribose) polymerase (PARP) and nuclear factor kappa B (NF-kappaB) both have been suggested to play a crucial role in inflammatory disorders. Unregulated increase of tumor necrosis factor-alpha (TNF-alpha) may also be pathogenic in inflammatory diseases. The aim of this study was to investigate the correlation between the number of Substance P (SP) containing nerve fibers and activated immune cells using immunohisto-, immunocytochemical (EM) and confocal laser microscopic methods. To investigate expression and activation of immune cells gastric biopsy samples from patients with chronic gastritis were used. The number of SP containing nerve fibers and activated immune cells increased significantly in gastritis. Using monoclonal p65 antibody, activated NF-kappaB was found in inflamed mucosa but was absent in uninflamed mucosa. Immunobinding for the activated form of p65 of NF-kappaB was found in 22% of macrophages and 45% of lymphocytes. The number of immune cells showing IR for NF-kappaB, PARP and TNF-alpha correlated with the increasing number of SP containing fibres. Confocal laser microscopy was used to confirm the colocalization of SP in TNF-alpha and NFkappaB positive lymphocytes and mast cells in inflamed mucosa. Immunoelectronmicroscopic investigation confirmed that these cells belong to lymphocytes, mast cells and macrophages.
Conclusions: The increase of SP in nerve fibers and in activated immune cells further activate the production of other proinflammatory mediators (e.g. TNF-alpha) and therefore generate the chronic inflammation.