The impact of periodontal infection and inflammation on sympathetic and sensitive nerve fibers.

• Applicant: Dr. Jeannette Oldeweme
• Subject Area: Dentistry, Oral Surgery
• Term: from 2015 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 273143998

Alterations in neurogenic modulation of inflamed tissue were found to be evident in chronic inflammatory diseases. There is evidence that the nervous system with its local secreted neurotransmitters plays a crucial role in the pathogenesis of chronic inflammatory autoimmune diseases. Current publications suggest a decrease of sympathetic nerve fibers in the following diseases: rheumatoid arthritis, type 1 diabetes mellitus and morbus crohn. The loss of sympathetic nerve fibers correlates with the degree of inflammation. The sympathetic neurotransmitters lead to anti-inflammatory effects. Accordingly, a loss of sympathetic nerve fibers leads to a decreased concentration of anti-inflammatory neurotransmitters in the tissue. In contrast, neurotransmitters secreted from sensitive nerve fibers mainly lead to inflammatory effects. Sympathetic and sensitive neurotransmitters have an opposing effect on the inflammatory reaction in chronic inflammatory diseases.Current publications suggest a decrease of sympathetic nerve fibers in chronic inflammatory disorders such as rheumatoid arthritis, intestinal endometriosis, pruritus, type 1 diabetes mellitus, peritoneal endometriosis and morbus crohn whereas the amount of sensitive nerve fibers was increased. The increase of sensitive nerve fibers leads to a higher concentration of the neurotransmitter substance P within the inflamed tissue and is thus leading to an enhanced activity of the disease. This results in an imbalance of sympathetic and sensitive nerve fibers in inflamed tissue.These results suggest that both sympathetic and sensitive nerve fibers are subject to a constant change of chronic inflammatory autoimmune diseases. These changes mainly occur in inflamed tissue whereas healthy regions are not affected.It is likely that alterations in neurogenic modulation are also detectable in patients suffering from periodontal disease, which is also known to be a chronic inflammatory disorder.The decrease of sympathetic nerve fibers is associated with an overexpression of nerve repellent factors. The repellent impulse leads to a redirection of axons and prevents a sprouting into these regions.The main objective of the proposed research project is to analyse sympathetic and sensitive nerve fibers in gingival tissue of patients with and without periodontal disease. In particular, the ratio of sympathetic and sensitive nerve fibers should be evaluated in correlation to local inflammation activity. Moreover, the regulatory mechanisms on sympathetic innervation due to nerve repellent factors (semaphorins) should be evaluated.

• DFG Programme: Research Grants