Salivary enzyme levels after scaling and interleukin-1 genotypes in Japanese patients with chronic periodontitis

BACKGROUND: Saliva has been used as a diagnostic fluid in medicine and dentistry. It is easy to collect using non-invasive methods. The intracellular enzymes present in saliva have been studied as markers of periodontal disease. The purpose of this study was to determine the salivary enzyme levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) after scaling and to clarify the influence of interleukin (IL)-1 genotypes on these enzyme levels. METHODS: Forty-nine Japanese patients with chronic periodontitis (24 men and 25 women; mean age: 55.1 years) were enrolled in this study. Measurements of clinical parameters including probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP) and collections of stimulated whole mixed saliva were performed at baseline and 4 weeks after scaling. After evaluation of salivary AST, ALT, and LDH levels, DNA was extracted from various cells in whole saliva. IL-1A+4845 G/T genotype was determined by polymerase chain reaction amplification, followed by enzyme digestion and electrophoresis. Statistical analysis was performed by the Wilcoxon signed-rank and Mann-Whitney U tests. A significant difference was set at P <0.05. RESULTS: Mean PD, CAL, and BOP values significantly decreased after scaling (mean +/- SE: 3.2 +/- 0.1 mm to 2.6 +/- 0.1 mm in PD; 3.9 +/- 0.2 mm to 3.3 +/- 0.2 mm in CAL; and 41% +/- 4% to 18% +/- 3% in BOP) (P <0.001). The values of AST, ALT, and LDH were 77.0 +/- 7.5, 43.9 +/- 5.5, and 753.4 +/- 96.5 (units per liter [U/l]) at baseline, and significantly decreased to 55.5 +/- 6.5, 30.0 +/- 5.5, and 394.7 +/- 34.0 (U/l) after scaling, respectively (P = 0.01, P = 0.006, and P <0.001). The carriage rate of the IL-1A+4845 allele 2 was 24.5%. No difference was noted in the decrease in PD, CAL, and BOP after scaling between the carriers (N = 12) and non-carriers (N = 37) of IL-1A+4845 allele 2. However, the IL-1A allele 2 non-carriers displayed a significant decrease in salivary AST and ALT levels (P <0.001), in contrast to the carriers who did not show any changes in the salivary levels of the enzymes after scaling. CONCLUSIONS: These results documented that salivary AST, ALT, and LDH levels reflect inflammation and destruction of periodontal tissue, suggesting clinically useful markers following periodontal therapy. In addition, although IL-1A+4845 alleles may not influence clinical parameters, they may influence post-scaling values of salivary AST and ALT.