Dual Mechanism of Brain Injury and Novel Treatment Strategy in Maple Syrup Urine Disease

Autor/inn/en	Zinnanti, William J.; Lazovic, Jelena; Griffin, Kathleen; Skvorak, Kristen J.; Paul, Harbhajan S.; Homanics, Gregg E.; Bewley, Maria C.; Cheng, Keith C.; LaNoue, Kathryn F.; Flanagan, John M.
Titel	Dual Mechanism of Brain Injury and Novel Treatment Strategy in Maple Syrup Urine Disease
Quelle	In: Brain, 132 (2009) 4, S.903-918 (16 Seiten) PDF als Volltext Verfügbarkeit
Sprache	englisch
Dokumenttyp	gedruckt; online; Zeitschriftenaufsatz
ISSN	0006-8950
DOI	10.1093/brain/awp024
Schlagwörter	Animals; Neurological Impairments; Diseases; Brain; Mothers; Stress Variables; Outcomes of Treatment; Cognitive Processes; Biochemistry; Metabolism; Dietetics + Suchen Sie Ihr Suchwort? Animal; Tier; Tiere; Neurodegenerative Erkrankung; Disease; Krankheit; Gehirn; Mother; Mutter; Cognitive process; Kognitiver Prozess; Biochemie; Stoffwechsel; Ernährungslehre
Abstract	Maple syrup urine disease (MSUD) is an inherited disorder of branched-chain amino acid metabolism presenting with life-threatening cerebral oedema and dysmyelination in affected individuals. Treatment requires life-long dietary restriction and monitoring of branched-chain amino acids to avoid brain injury. Despite careful management, children commonly suffer metabolic decompensation in the context of catabolic stress associated with non-specific illness. The mechanisms underlying this decompensation and brain injury are poorly understood. Using recently developed mouse models of classic and intermediate maple syrup urine disease, we assessed biochemical, behavioural and neuropathological changes that occurred during encephalopathy in these mice. Here, we show that rapid brain leucine accumulation displaces other essential amino acids resulting in neurotransmitter depletion and disruption of normal brain growth and development. A novel approach of administering norleucine to heterozygous mothers of classic maple syrup urine disease pups reduced branched-chain amino acid accumulation in milk as well as blood and brain of these pups to enhance survival. Similarly, norleucine substantially delayed encephalopathy in intermediate maple syrup urine disease mice placed on a high protein diet that mimics the catabolic stress shown to cause encephalopathy in human maple syrup urine disease. Current findings suggest two converging mechanisms of brain injury in maple syrup urine disease including: (i) neurotransmitter deficiencies and growth restriction associated with branched-chain amino acid accumulation and (ii) energy deprivation through Krebs cycle disruption associated with branched-chain ketoacid accumulation. Both classic and intermediate models appear to be useful to study the mechanism of brain injury and potential treatment strategies for maple syrup urine disease. Norleucine should be further tested as a potential treatment to prevent encephalopathy in children with maple syrup urine disease during catabolic stress. (As Provided).
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Erfasst von	ERIC (Education Resources Information Center), Washington, DC
Update	2017/4/10