Kosaka_2005_Clin.Chim.Acta_359_156

BACKGROUND: It is known that serum paraoxonase activity decreases in patients with atherosclerotic diseases such as type 2 diabetes mellitus. Paraoxonase hydrolyzes homocysteine thiolactone, which is thought to be an endogenous substrate. The relationship between the status of atherosclerosis and homocysteine thiolactonase activity in patients with type 2 diabetes mellitus was investigated. METHOD: Serum homocysteine thiolactonase activities in 207 patients with type 2 diabetes mellitus were measured with a recently developed commercially available assay. RESULTS: The coefficient of variation for the assay was <0.7%. Serum paraoxonase and arylesterase activities were dependent on the PON1 192 polymorphism expressed by the subjects but homocysteine thiolactonase activity was not affected. A tendency for a negative association between homocysteine thiolactonase activity and the thickness of the carotid intima media was observed in patients with type 2 diabetes mellitus. CONCLUSIONS: The serum homocysteine thiolactonase activity may represent the status of atherosclerosis in patients with type 2 diabetes mellitus. Since the assay can be used with a routine analyzer, the activities of thousands of samples can be measured with excellent precision in a few hours.