ABSTRACT
Maple syrup urine disease (MSUD) is an inborn error of metabolism that causes elevated leucine in the setting of acute illnesses. We describe an 8-year-old boy with MSUD who developed acute pancreatitis and subsequent leucinosis. This case highlights the complexities of fluid management in patients with MSUD.
Subject(s)
Maple Syrup Urine Disease/complications , Maple Syrup Urine Disease/therapy , Pancreatitis/etiology , Pancreatitis/therapy , Child , Humans , Male , Maple Syrup Urine Disease/diagnosis , Pancreatitis/diagnosisABSTRACT
Maple syrup urine disease (MSUD) is a rare metabolic disorder associated with acute and chronic brain dysfunction. This condition has been shown to lead to macroscopic cerebral alterations that are visible on imaging studies. Cerebral oedema is widely considered to be detrimental for MSUD patients; however, the mechanisms involved are still poorly understood. Therefore, we investigated whether acute administration of branched-chain amino acids (BCAA) causes cerebral oedema, modifies the Na(+),K(+)-ATPase activity, affects the permeability of the blood-brain barrier (BBB) and alters the levels of cytokines in the hippocampus and cerebral cortex of 10-day-old rats. Additionally, we investigated the influence of concomitant administration of dexamethasone on the alterations caused by BCAA. Our results showed that the animals submitted to the model of MSUD exhibited an increase in the brain water content, both in the cerebral cortex and in the hippocampus. By investigating the mechanism of cerebral oedema, we discovered an association between H-BCAA and the Na(+),K(+)-ATPase activity and the permeability of the BBB to small molecules. Moreover, the H-BCAA administration increases Il-1ß, IL-6 and TNF-α levels in the hippocampus and cerebral cortex, whereas IL-10 levels were decreased in the hippocampus. Interestingly, we showed that the administration of dexamethasone successfully reduced cerebral oedema, preventing the inhibition of Na(+),K(+)-ATPase activity, BBB breakdown and the increase in the cytokines levels. In conclusion, these findings suggest that dexamethasone can improve the acute cerebral oedema and brain injury associated with high levels of BCAA, either through a direct effect on brain capillary Na(+),K(+)-ATPase or through a generalized effect on the permeability of the BBB to all compounds.
Subject(s)
Blood-Brain Barrier/pathology , Brain Edema/prevention & control , Dexamethasone/therapeutic use , Hippocampus/enzymology , Maple Syrup Urine Disease/complications , Maple Syrup Urine Disease/drug therapy , Sodium-Potassium-Exchanging ATPase/metabolism , Amino Acids, Branched-Chain/administration & dosage , Animals , Blood-Brain Barrier/drug effects , Blood-Brain Barrier/metabolism , Brain Edema/complications , Brain Edema/drug therapy , Brain Edema/pathology , Dexamethasone/administration & dosage , Dexamethasone/pharmacology , Disease Models, Animal , Hippocampus/pathology , Male , Maple Syrup Urine Disease/enzymology , Maple Syrup Urine Disease/pathology , Rats, Wistar , Tumor Necrosis Factor-alpha/metabolismABSTRACT
Maple syrup urine disease (MSUD) is an autosomal recessive metabolic disorder resulting from deficiency of branched-chain α-keto acid dehydrogenase complex leading to branched chain amino acids (BCAA) leucine, isoleucine, and valine accumulation as well as their corresponding transaminated branched-chain α-keto acids. MSUD patients present neurological dysfunction and cognitive impairment. Here, we investigated whether acute and chronic administration of a BCAA pool causes impairment of acquisition and retention of avoidance memory in young rats. We have used two administration protocols. Acute administration consisted of three subcutaneous administrations of the BCAA pool (15.8 µL/g body weight at 1-h intervals) containing 190 mmol/L leucine, 59 mmol/L isoleucine, and 69 mmol/L valine or saline solution (0.85% NaCl; control group) in 30 days old Wistar rats. Chronic administration consisted of two subcutaneous administrations of BCAA pool for 21 days in 7 days old Wistar rats. N-acetylcysteine (NAC; 20 mg/kg) and deferoxamine (DFX; 20 mg/kg) co administration influence on behavioral parameters after chronic BCAA administration was also investigated. BCAA administration induced long-term memory impairment in the inhibitory avoidance and CMIA (continuous multiple-trials step-down inhibitory avoidance) tasks whereas with no alterations in CMIA retention memory. Inhibitory avoidance alterations were prevented by NAC and DFX. BCAA administration did not impair the neuropsychiatric state, muscle tone and strength, and autonomous function evaluated with the SHIRPA (SmithKline/Harwell/ImperialCollege/RoyalHospital/Phenotype Assessment) protocol. Taken together, our results indicate that alterations of motor activity or emotionality probably did not contribute to memory impairment after BCAA administration and NAC and DFX effects suggest that cognition impairment after BCAA administration may be caused by oxidative brain damage.
Subject(s)
Antioxidants/therapeutic use , Maple Syrup Urine Disease/complications , Memory Disorders/complications , Memory Disorders/prevention & control , Memory/drug effects , Acetylcysteine/pharmacology , Acetylcysteine/therapeutic use , Amino Acids, Branched-Chain , Animals , Antioxidants/pharmacology , Deferoxamine/pharmacology , Deferoxamine/therapeutic use , Disease Models, Animal , Male , Maple Syrup Urine Disease/chemically induced , Memory Disorders/drug therapy , Rats , Rats, WistarABSTRACT
INTRODUCTION: Maple syrup urine disease (MSUD) is a genetic disorder that produces ketoacidosis crises and neurological complications often leading to death. The age of diagnosis and treatment determine a child's adequate and healthy outcome. OBJECTIVE: Describe the characteristics of a pediatric Mexican cohort with MSUD. MATERIAL AND METHODS: Retrospective analysis of MSUD cases seen at our Metabolic Unit between 1991- 2006. RESULTS: We studied 36 patients; three were initially detected through neonatal screening, one of them done in Mexico and two in the United States. The latter were given timely treatment and developed normally, both intellectually and physically. The patient detected in Mexico was not given adequate treatment and died at 3 months of age. The remaining 33 patients were diagnosed between 2-24 months using standard biochemical tests performed after symptoms became noticeable. All symptomatic patients had high levels of branched-chain amino acids. Hypotonia, refusal to eat and seizures were the most frequent symptoms. The cohort's mortality was 50% (18/36), while 81.2% (13/18) of survivors displayed cognitive impairment. DISCUSSION: Mexico needs a comprehensive treatment protocol for the care of MSUD patients including newborn screening, early treatment, follow-up and genetic counseling.
Subject(s)
Maple Syrup Urine Disease/complications , Maple Syrup Urine Disease/mortality , Psychomotor Disorders/etiology , Cross-Sectional Studies , Female , Humans , Infant , Infant, Newborn , Male , Mexico , Retrospective StudiesABSTRACT
Introducción: La enfermedad de jarabe de arce es una enfermedad genética que produce crisis de cetoacidosis y deterioro neurológico progresivo que llevan a un coma fatal. El inicio del tratamiento temprano es determinante en el pronóstico. Objetivo: Describir las características de una cohorte de pacientes mexicanos con enfermedad de orina con olor a jarabe de arce (EOJA). Material y métodos: Se hizo un análisis retrospectivo de casos de EOJA de 1991 a 2006. Resultados: Encontramos 36 pacientes (16 niñas y 20 niños). Tres fueron inicialmente detectados mediante tamiz neonatal, uno de ellos realizado en México y los otros dos en el extranjero. Estos últimos recibieron tratamiento oportuno y exhiben desarrollo psicomotor normal. El caso detectado en México no recibió tratamiento adecuado y falleció. Los otros 33 pacientes se diagnosticaron entre los 2 y los 73 meses de edad mediante tamiz metabólico (postsintomático) ante la sospecha clínica. Todos los pacientes sintomáticos presentaron resultado positivo a la prueba de dinitrofenilhidrazina y aminoácidos ramificados elevados. La hipotonía, rechazo al alimento, y las crisis convulsivas fueron los síntomas más frecuentes. En esta cohorte, la mortalidad fue del 50 % (18/36) y el 81.2 % de los sobrevivientes (13/18) muestran actualmente retraso psicomotor. Discusión: Es necesario establecer en México un modelo de atención integral para la EOJA que incluya la detección presintomática preventiva, el tratamiento temprano, el seguimiento y asesoramiento genético.
INTRODUCTION: Maple syrup urine disease (MSUD) is a genetic disorder that produces ketoacidosis crises and neurological complications often leading to death. The age of diagnosis and treatment determine a child's adequate and healthy outcome. OBJECTIVE: Describe the characteristics of a pediatric Mexican cohort with MSUD. MATERIAL AND METHODS: Retrospective analysis of MSUD cases seen at our Metabolic Unit between 1991- 2006. RESULTS: We studied 36 patients; three were initially detected through neonatal screening, one of them done in Mexico and two in the United States. The latter were given timely treatment and developed normally, both intellectually and physically. The patient detected in Mexico was not given adequate treatment and died at 3 months of age. The remaining 33 patients were diagnosed between 2-24 months using standard biochemical tests performed after symptoms became noticeable. All symptomatic patients had high levels of branched-chain amino acids. Hypotonia, refusal to eat and seizures were the most frequent symptoms. The cohort's mortality was 50% (18/36), while 81.2% (13/18) of survivors displayed cognitive impairment. DISCUSSION: Mexico needs a comprehensive treatment protocol for the care of MSUD patients including newborn screening, early treatment, follow-up and genetic counseling.
Subject(s)
Humans , Male , Female , Infant, Newborn , Infant , Maple Syrup Urine Disease/complications , Maple Syrup Urine Disease/mortality , Psychomotor Disorders/etiology , Cross-Sectional Studies , Mexico , Retrospective StudiesABSTRACT
Accumulation of the branched-chain alpha-keto acids (BCKA), alpha-ketoisocaproic acid (KIC), alpha-keto-beta-methylvaleric acid (KMV) and alpha-ketoisovaleric acid (KIV) and their respective branched-chain alpha-amino acids (BCAA) occurs in tissues and biological fluids of patients affected by the neurometabolic disorder maple syrup urine disease (MSUD). The objective of this study was to verify the effect of the BCKA on S100B release from C6 glioma cells. The cells were exposed to 1, 5 or 10 mM BCKA for different periods and the S100B release was measured afterwards. The results indicated that KIC and KIV, but not KMV, significantly enhanced S100B liberation after 6 h of exposure. Furthermore, the stimulatory effect of the BCKA on S100B release was prevented by coincubation with the energetic substrate creatine and with the N-nitro-l-arginine methyl ester (l-NAME), a nitric oxide synthase inhibitor, indicating that energy deficit and nitric oxide (NO) were probably involved in this effect. Furthermore, the increase of S100B release was prevented by preincubation with the protein kinase inhibitors KN-93 and H-89, indicating that KIC and KIV altered Ca2+/calmodulin (PKCaMII)- and cAMP (PKA)-dependent protein kinases activities, respectively. In contrast, other antioxidants such as glutathione (GSH) and trolox (soluble vitamin E) were not able to prevent KIC- and KIV-induced increase of S100B liberation, suggesting that the alteration of S100B release caused by the BCKA is not mediated by oxidation of sulfydryl or other essential groups of the enzyme as well as by lipid peroxyl radicals. Considering the importance of S100B for brain regulation, it is conceivable that enhanced liberation of this protein by increased levels of BCKA may contribute to the neurodegeneration characteristic of MSUD patients.
Subject(s)
Brain/metabolism , Keto Acids/metabolism , Maple Syrup Urine Disease/complications , Maple Syrup Urine Disease/metabolism , Nerve Degeneration/etiology , Nerve Degeneration/metabolism , Nerve Growth Factors/metabolism , Neuroglia/metabolism , S100 Proteins/metabolism , Animals , Brain/physiopathology , Cell Death/drug effects , Cell Death/physiology , Cell Line, Tumor , Creatine/metabolism , Creatine/pharmacology , Dose-Response Relationship, Drug , Energy Metabolism/drug effects , Energy Metabolism/physiology , Enzyme Inhibitors/pharmacology , Keto Acids/pharmacology , Maple Syrup Urine Disease/physiopathology , Nerve Degeneration/physiopathology , Neuroglia/drug effects , Nitric Oxide/metabolism , Nitric Oxide Synthase Type I/antagonists & inhibitors , Nitric Oxide Synthase Type I/metabolism , Oxidation-Reduction/drug effects , Oxidative Stress/drug effects , Oxidative Stress/physiology , Protein Kinases/drug effects , Protein Kinases/metabolism , Rats , S100 Calcium Binding Protein beta SubunitABSTRACT
Maple syrup urine disease is an inherited metabolic disorder characterized by tissue accumulation of branched-chain amino acids and their corresponding keto acids in the affected children. Although this disorder is predominantly characterized by neurological symptoms, only few studies were carried out to investigate its neuropathology. In this study we investigated the effect of the metabolites accumulating in maple syrup urine disease on the in vitro uptake of [3H]glutamate by synaptic vesicles of rat brain. Synaptic vesicle preparations from whole brain of male adult Wistar rats (200-250 g) were incubated with the branched-chain amino acids and their corresponding keto acids at final concentrations ranging from 0.25 to 10 mM for the determination of glutamate uptake. Glutamate uptake was significantly inhibited by L-leucine, L-isoleucine, L-2-ketoisocaproic acid and L-2-keto-3-methylvaleric acid by approximately 60%, whereas L-valine and L-2-ketoisovaleric acid showed no effect. We also verified that the metabolites probably act by competitive inhibition. Therefore, it is possible that extracellular glutamate levels may be increased in maple syrup urine disease and that excitotoxicity may be involved in the neuropathology of this disorder.
Subject(s)
Brain/drug effects , Glutamic Acid/metabolism , Maple Syrup Urine Disease/metabolism , Neurons/drug effects , Synaptic Vesicles/drug effects , Animals , Brain/metabolism , Brain/physiopathology , Hemiterpenes , Isoleucine/metabolism , Isoleucine/pharmacology , Keto Acids/metabolism , Keto Acids/pharmacology , Leucine/metabolism , Leucine/pharmacology , Male , Maple Syrup Urine Disease/complications , Maple Syrup Urine Disease/physiopathology , Neurons/metabolism , Rats , Rats, Wistar , Synaptic Vesicles/metabolism , Synaptosomes/drug effects , Synaptosomes/metabolism , Valine/metabolism , Valine/pharmacologyABSTRACT
Neurological dysfunction is common in patients with maple syrup urine disease (MSUD). However, the mechanisms underlying the neuropathology of this disorder are poorly understood. We determined the concentrations of all amino acids in plasma of patients with MSUD during crises (with severe CNS symptoms) and after recovery in the hope of detecting possible alterations of these levels during metabolic decompensation. Blood samples obtained from 11 children with MSUD aged 1 month to 7 years and from 10 age-matched controls (5 months to 6 years) with no evidence of metabolic disease were examined for their amino acid content by high-performance liquid chromatography. We observed that leucine, isoleucine and valine concentrations were respectively 30, 9 and 3 times higher than normal values, whereas the concentrations of the large neutral amino acids (LNAA) phenylalanine, tyrosine, tryptophan and methionine were significantly lower during metabolic decompensation as compared to the controls. In addition, concentrations of leucine, but not of valine or isoleucine, were inversely related to the LNAA concentrations in plasma. The concentrations of these amino acids in plasma returned to normal values when patients were clinically well. CSF amino acid concentrations also showed decreased amounts of LNAA and increased concentrations of branched-chain amino acids. It is possible that the decrease in plasma concentrations of LNAA may lead to a deficit of these essential amino acids in the brain as well as of their products such as proteins and neurotransmitters, a fact that might be related to the neurological dysfunction of MSUD.
Subject(s)
Amino Acids, Neutral/blood , Amino Acids, Neutral/cerebrospinal fluid , Maple Syrup Urine Disease/blood , Maple Syrup Urine Disease/cerebrospinal fluid , Brain/metabolism , Case-Control Studies , Child , Child, Preschool , Humans , Infant , Maple Syrup Urine Disease/complications , Nervous System Diseases/etiology , Nervous System Diseases/metabolismABSTRACT
STUDY OBJECTIVE: The discovery of pancreatitis in two children with methylmalonic acidemia led us to review the experience with pancreatitis in a large number of patients with organic acidemias to determine whether pancreatitis is an important complication of these disorders. DESIGN: Case series. SETTING: Pediatric metabolism services at five tertiary care centers. PATIENTS: Records of all patients with organic acidemias followed at the five institutions during the past 10 years were reviewed. Pancreatitis was recognized by symptoms and laboratory findings and confirmed by imaging studies, surgery, or autopsy. At three institutions all cases of pancreatitis in children younger than 10 years were reviewed. MEASUREMENTS AND RESULTS: Nine children with pancreatitis (seven with acute and two with chronic cases) were identified among 108 children with branched-chain organic acidemias. They ranged in age from 13 months to 9 years. Five had methylmalonic acidemia, three had isovaleric acidemia, and one had maple syrup urine disease. There were three deaths; acute hemorrhagic pancreatitis occurred in two children, and chronic pancreatitis was found at autopsy in a third. All three patients with isovaleric acidemia and pancreatitis were identified after the occurrence of pancreatitis. The survey of pancreatitis at three institutions found 57 other patients (none with an inborn error) in addition to three patients with inborn errors included in this study. CONCLUSIONS: Acute or chronic pancreatitis may complicate branched-chain organic acidemias and must be considered in the assessment of patients with these disorders who have acute clinical deterioration and vomiting, abdominal pain, encephalopathy or shock, or milder symptoms. Conversely, an inborn error of organic acid metabolism should be considered in children with pancreatitis of unknown origin.
Subject(s)
Amino Acid Metabolism, Inborn Errors/complications , Oxidoreductases Acting on CH-CH Group Donors , Pancreatitis/etiology , Acute Disease , Child , Child, Preschool , Chronic Disease , Female , Humans , Infant , Infant, Newborn , Isovaleryl-CoA Dehydrogenase , Male , Maple Syrup Urine Disease/complications , Methylmalonic Acid/urine , Oxidoreductases/deficiencyABSTRACT
Acute metabolic decompensation in maple syrup urine disease (MSUD) during otherwise minor illnesses has generally been presumed to result from massive release of leucine from protein catabolism. A stable isotope method based on the continuous infusion of (2H5)phenylalanine was used to measure protein metabolism in vivo in two children with MSUD during acute illness and when well. Net protein catabolism was greater in the unwell state (0.51 and 0.40 gm/kg per 24 hours in each child, respectively) than in the basal state (0.34 and 0.32). This rate of release of leucine from protein is compatible only with a slow (several days) rather than a dramatic rise in plasma leucine levels during acute illness in MSUD. Poor oral intake leading to a relative increase in time spent in the fasting state appears to be a more important determinant of increasing leucine levels than the catabolic effect of infection in itself. These factors suggested that branched-chain amino acid restriction should be commenced at the start of minor illness in children with MSUD, and that intake of other nutrients should be maintained or increased throughout the illness. A regimen based on these concepts was used during nine episodes of minor illness in two children with MSUD. Plasma branched-chain amino acid levels remained acceptable (less than 700 mumol/L) throughout each of these episodes. Dietary supplementation of this type may reduce the risk of metabolic decompensation during acute illnesses in children with MSUD.
Subject(s)
Leucine/metabolism , Maple Syrup Urine Disease/metabolism , Proteins/metabolism , Acute Disease , Amino Acids, Branched-Chain/blood , Child, Preschool , Female , Humans , Infant , Maple Syrup Urine Disease/complications , Maple Syrup Urine Disease/diet therapy , Respiratory Tract Infections/complicationsABSTRACT
Four children with the classic form of maple syrup urine disease (MSUD) died of cerebral edema during an intercurrent infection that caused severe dehydration and acidosis. The diagnosis of MSUD had been established during the neonatal period in all four patients, on day 1 of life in three of them. All were in satisfactory control before the intercurrent illness. Two patients underwent peritoneal dialysis. Signs of brain-stem compression occurred after treatment, when biochemical abnormalities were improving. Computed tomography of the head, which was done in two patients, revealed cerebral edema; one of these patients also had subarachnoid hemorrhage. Autopsy in one case revealed cerebral edema with herniation. Our experience documents that cerebral edema may occur in the older child with MSUD as well as in the neonate. The pathogenesis of cerebral edema in MSUD remains unclear. Early treatment of dehydration and acidosis may prevent the catastrophic consequences that we have observed.
Subject(s)
Brain Edema/etiology , Maple Syrup Urine Disease/complications , Acute Disease , Brain Edema/prevention & control , Child, Preschool , Dehydration/etiology , Female , Humans , PrognosisABSTRACT
We report a controlled study of intellectual outcome in 16 children with maple syrup urine disease (MSUD) that compares the outcome of MSUD diagnosed after symptoms became apparent with that of MSUD diagnosed prospectively and in unaffected siblings and parents. The mean IQ (+/- SD) score in the children with classic MSUD was 78 +/- 24; however, there were two discrete groups: one with normal IQ (greater than 84) whose MSUD had been diagnosed at a mean age of 3.5 days and a second group, with IQ below normal, whose MSUD was diagnosed at a mean of 10 days of age. Affected children treated presymptomatically had higher IQ scores than their affected siblings treated when their disease was symptomatic. Multiple regression analysis indicated that the important influences on IQ were age at the time of diagnosis and long-term metabolic control; control at the time of testing also might have affected performance. The mean score of unaffected siblings was 92 +/- 5 and the mean parental IQ was 83 +/- 9. The mean IQ scores of children with variant MSUD, 97 +/- 4, was similar to that of their parents, 103 +/- 6. This study was not longitudinal and thus could not identify subtle developmental learning problems. We conclude that early and meticulous treatment of MSUD can result in intellectually normal children.