Role of saliva, gingival crevicular fluid and oral microbiota in gastrointestinal diseases

The aim of this dissertation was the evaluation of the role of saliva, gingival crevicular fluid and oral microbiota in two gastrointestinal conditions: colorectal cancer and Helicobacter pylori gastritis. In the first study two specific sub-gingival bacteria, Fusobacterium nucleatum and Porphyromonas gingivalis, pathogens typical of periodontal disease, were analysed in order to detect possible correlations with the tumoral changes leading to colorectal cancer development. In particular, Fusobacterium nucleatum load was found different on the intestinal mucosa of patients with a diagnosis of colorectal cancer and adenoma, compared to the healty control group; on the other hand Phorpyromonas gingivalis, although non directly related with carcinogenesis, might promote the development of the first bacterium. In the second study the relatioship between the presence of Helicobacter pylori in the stomach and in the oral cavity of patients with and without gastric infection was evaluated. Data suggested that periodontal pockets could represent a favourable enviroment where the microrganism is able to replicate, slipping away from human immune system surveillance, and spread within saliva, reaching the stomach during swallowing and possibly contributing to gastric disease recrudescence. In the end, a total number of 212 patients were recruited in this experimental work and each study contributed to better understand the relevant role of oral microbiota in gastrointestinal diseases and the importance of a proper oral hygene mantainance in order to reduce the risk of developing dangerous extra-oral illnesses.