Salivary lactate dehydrogenase and aminotransferases in diabetic patients

Diabetes mellitus (DM) is a group of metabolic diseases resulting from impaired insulin secretion and/or action. DM is characterized by hyperglycemia that can lead to the dysfunction or damage of organs, including the salivary glands. The aim of this study was to compare the levels of salivary lactate dehydrogenase (LDH), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) in diabetic patients. The study was approved by the Bioethics Committee of Wroclaw Medical University (Poland). The study comprised 90 adults of both sexes, aged 21 to 57 years. The patients were divided into 3 groups: type 1 diabetics (D1), type 2 diabetics (D2), and a healthy control group (C). Each group consisted of 30 age- and sex-matched subjects. Total protein (P, by Lowry method), LDH, AST, ALT (with Alpha Diagnostics kits), and salivary flow rate were measured in unstimulated mixed saliva. The level of glycosylated hemoglobin (HbA1c) was measured with DCA 2000 Reagent Kit. The obtained data were analyzed using the Mann–Whitney U test and the Spearman rank at a significance level of P < 0.05 with the use of STATISTICA 9.0 software. In comparison with C, D1 presented a significantly higher activity of LDH (P < 0.001), AST (P < 0.001), and ALT (P < 0.01), whereas D2 indicated higher levels of LDH (P < 0.001) and ALT (P < 0.05) compared with C. Comparing D1 to D2, approximately 3-fold higher activity of AST (P < 0.01) and approximately 4.5-fold higher activity of ALT (P < 0.01) was observed. Higher levels of salivary LDH, AST, and ALT in D1 compared with D2 and C confirm that salivary glands of D1 might be attributed to autoimmunological damage associated with the pathomechanism of DM.