Organic acids and branched-chain amino acids in body fluids before and after multiple exchange transfusions in maple syrup urine disease.
We successfully treated a critically ill infant with the classical type of maple syrup urine disease by multiple exchange transfusions via a peripheral artery and vein and with positive calorie supplementation in the early stage of therapy. Clinical improvement was definite after the plasma leucine level fell below 1 mmol/l. There was a close linear correlation between plasma concentrations of branched-chain amino acids and their corresponding branched-chain alpha-keto acids and branched-chain alpha-hydroxy acids. alpha-Hydroxy acids were more easily excreted in the urine than alpha-keto acids and amino acids. Our studies on urinary organic acids supported the existence of minor metabolic pathways of branched-chain alpha-keto acids, although they were not thought to be important in eliminating accumulated alpha-keto acids. Urinary excretion of succinic acid and alpha-ketoglutaric acid, which are components of the citric acid cycle, increased transiently during the patient's convalescence. The cerebrospinal fluid/plasma ratios for branched-chain amino acids, alpha-keto acids, and alpha-hydroxy acids were very high before the transfusions and decreased after improvement. The cerebrospinal fluid/plasma ratios for 5-carbon acids, alpha-ketoisovaleric acid and alpha-hydroxyisovaleric acid were much higher than for other branched-chain acids not only in the patient but also in normal controls. Cerebrospinal fluid levels of alpha-ketoisocaproic acid and alpha-hydroxyisovaleric acid were as high as 1 mmol/l in our patient.
D000597:Amino Acids, Branched-Chain / Q000378:metabolism*; D001826:Body Fluids / Q000378:metabolism*; D002264:Carboxylic Acids / Q000378:metabolism*; D005078:Exchange Transfusion, Whole Blood; D005260:Female; D006801:Humans; D006880:Hydroxy Acids / Q000378:metabolism; D007231:Infant, Newborn; D007651:Keto Acids / Q000378:metabolism; D007656:Ketoglutaric Acids / Q000652:urine; D008375:Maple Syrup Urine Disease / Q000628:therapy*; D013386:Succinates / Q000652:urine; D019802:Succinic Acid
D000597:Amino Acids, Branched-Chain; D002264:Carboxylic Acids; D006880:Hydroxy Acids; D007651:Keto Acids; D007656:Ketoglutaric Acids; D013386:Succinates; D019802:Succinic Acid