Establishment of a rapid diagnosis of congenital lactic acidosis using peripheral blood samples

Research Project

Project/Area Number	61570459
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	Pediatrics
Research Institution	University of Tokushima
Principal Investigator	KURODA Yasuhiro School of Medicine, University of Tokushima, 医学部, 教授 (20035471)
Co-Investigator(Kenkyū-buntansha)	TAKEDA Eiji School of Medicine, University of Tokushima, 医学部附属病院, 講師 (00144973)
Project Period (FY)	1986 – 1987
Project Status	Completed (Fiscal Year 1987)
Budget Amount *help	¥2,400,000 (Direct Cost: ¥2,400,000) Fiscal Year 1987: ¥1,000,000 (Direct Cost: ¥1,000,000) Fiscal Year 1986: ¥1,400,000 (Direct Cost: ¥1,400,000)
Keywords	Congenital lactic acidosis / Lactate / Pyruvate / Metabolic inborn errors / 有機酸代謝異常症 / 末梢血 / 酵素診断
Research Abstract	Congenital lactic acidosis of childhood is characterized by persistently high levels of blood pyruvate and lactate. In Japan, the number of reported cases of congenital lactic acidosis is increasing. Hereditary deficiencies leading to lactic acidosis have been demonstrated in the enzymes of the pyruvate dehydrogenase complex, in the key enzymes of the pathway of gluconeogenesis and in the enzymes of the electron transport system. For establishment of a diagnosis of congenital lactic acidosis, the usual procedures are measurements of the activities of enzymes involved in pyruvate metabolism in cultured skin fibroblasts. However, it takes long time to culture skin fibroblasts. Therefore, we had developed a rapid method for diagnosis of congenital lactic acidosis using platelets and lymphocytes separated from peripheral blood samples. In this method, the rates of decarboxylation of (1-^<14>C)pyruvate and (3-^<14>C)pyruvate and the activity of cytochrome c oxidase in platelets and the activities of pyruvate carboxylase, and phosphoenol pyruvate carboxykinase in lymphocytes were measured. Platelets and lymphocytes were separated from the peripheral blood samples of 40 patients with congenital lactic acidosis which were transported from the hospitals in every part of Japan. Then, the rates of decarboxylation of pyruvate and the activities of enzymes involved in pyruvate metabolism were measured. The rates of decarboxylation of pyruvate and the activity of cytochrome c oxidase in the platelets and the activity of pyruvate carboxylase in the lymphocytes were unstable and decreased during the trans portation of blood samples. Therefore, in order to diagnose the enzyme defects, blood samples which were simultaneously obtained from control subjects were required. Using this method, we found a patient with pyruvate dehydrogenase deficiency in 40 patients with congenital lactic acidosis.