Salivary thiols and enzyme markers of cell damage in periodontal disease

Objectives: Recent studies describe the potential use of biochemical markers in the evaluation of the severity of periodontitis; moreover, patients suffering from periodontitis frequently complain of halitosis (breath malodour), mainly depending on volatile compounds (e.g. hydrogen sulphide, methyl mercaptan, etc.) produced by anaerobic metabolism of oral bacteria and involving sulphur-containing amino acids. In this study, salivary sulphur compounds, such as cysteine, cysteinylglycine and glutathione and some markers of cellular damage (lactate dehydrogenase and aspartate amino transferase), were measured in periodontitis patients and correlated with the periodontal probing pocketʹs depth. Design and methods: Twenty-two periodontitis patients and forty control subjects were studied for the salivary activities of lactate dehydrogenase and aspartate aminotransferase and cysteine, cysteinylglycine and glutathione concentrations. The periodontitis patients were divided into two subgroups based on the severity of periodontal disease, expressed as median periodontal probing pocket depth (> or < 5 mm). Enzyme activities were measured by using an automated clinical analyzer; cysteine, cysteinylglycine and glutathione concentrations were measured by HPLC equipped with fluorescence detector. Results: A statistically significant increase of the salivary parameters level (cysteine, cysteinylglycine, glutathione, aspartate aminotransferase and lactate dehydrogenase) was found in the patient subgroup with periodontal probing pocket depth > 5 mm, the salivary cysteine concentrations showing the most significant correlation. Conclusions: Salivary cysteine, a direct precursor of hydrogen sulphide, could be considered reliable markers for the oral tissue damage severity in periodontitis patients.