Pathophysiology of maple syrup urine disease: Focus on the neurotoxic role of the accumulated branched-chain amino acids and branched-chain α-keto acids.

Maple syrup urine disease (MSUD) is an autosomal recessive neurometabolic disorder caused by severe deficiency of branched-chain α-keto acid dehydrogenase complex activity, which catalyzes the oxidative decarboxylation of the branched-chain α-keto acids (BCKA). The metabolic blockage results in tissue accumulation and high urinary excretion of the branched-chain amino acids (BCAA) leucine, isoleucine and valine, as well as alloisoleucine, and their respective BCKA α-ketoisocaproic (α-KIC), α-ketoisovaleric and α-keto-ß-methylvaleric acids. Affected patients usually manifest acute episodes of encephalopathy associated with seizures, coma and life-threatening cerebral edema in the first weeks of life, which is followed by progressive neurological deterioration with motor delay, ataxia, intellectual disability and psychiatric symptoms. The pathophysiology of the brain damage in MSUD has been mainly focused on brain amino acid imbalance leading to deficient cerebral protein and neurotransmitter synthesis. However, the acute episodes of severe neurological symptoms accompanied by large increases of BCKA/BCAA levels suggest neurotoxic actions of these compounds. In this particular, mounting evidence from humans and animal models support an important role of particularly leucine and α-KIC on the pathogenesis of the brain injury in MSUD. In this review we will present the current knowledge of the major mechanisms presumably involved in MSUD neuropathology and highlight the neurotoxic properties of the BCAA and BCKA, disturbing brain bioenergetics and redox homeostasis, besides inducing neuroinflammation. We suggest that these pathomechanisms may contribute to the neurological sequelae of MSUD patients and hopefully allow the design of novel therapeutic strategies, including antioxidant and bioenergetics stimulating drugs targeting the mitochondria.

Enfermedad de orina en jarabe de arce: mejoría clínica asociada a detección precoz y manejo oportuno. Reporte de caso y revisión de literature / Doença de urina em xarope de arce: melhoria clínica relacionada á detecção precoce e manejo oportuno. Reporte de caso e revisão de literatura / Maple syrup urinary disease: clinical improvement associated with early detection and management. Case report and literature review

La enfermedad de orina en jarabe de arce es un error innato del metabolismo de los cetoácidos de cadena ramificada, cuya acumulación produce una encefalopatía neonatal grave y que de no ser diagnosticada y tratada de forma precoz y oportuna, lleva invariablemente a la aparición de secuelas neurológicas permanentes y a un posterior desenlace letal. El presente artículo busca, mediante la descripción de un caso clínico sucedido en el Hospital Militar Central de Bogotá, hacer una revisión de la literatura acerca de la enfermedad, resaltando los mecanismos fisiopatológicos, la detección por diferentes pruebas de laboratorio, así como las estrategias de manejo, demostrando que gracias a los progresos realizados en su comprensión y enfoque, actualmente se puede hablar de evitar la mortalidad, alcanzando en muchos casos, una sobrevida a largo plazo sin mayores secuelas neurológicas, todo ello con un manejo interdisciplinario que logre un control metabólico adecuado...

Maple syrup urine disease is an inborn error of the metabolism of branched chain keto-acids whose accumulation produces a serious neonatal encephalopathy, which if not diagnosed and treated in a precocious and opportune way, will invariably lead to the appearance of permanent neurological impairments and an ulterior lethal outcome. The present article intends, by means of the description of a clinical case which occurred at the Hospital Militar Central, to perform a review of the existent literature on this disease, to revise its fisiopathological mechanisms as well as its detection using different laboratory tests and the different care strategies, to demonstrate that, thanks to the progress achieved in its understanding and focus, at the present moment we can speak of avoiding mortality, accomplishing in many cases long term survival without important neurological consequences, all by means of an interdisciplinary approach that achieves an appropriate metabolic control...

A doença de urina em xarope de arce é um erro inato do metabolismo dos cetoácidos de corrente ramificada, cuja acumulação produz uma encefalopatia neonatal grave e que de não ser diagnosticada e tratada de forma precoce e oportuna, leva invariavelmente à aparição de seqüelas neurológicas permanentes e a um posterior desenlace letal. O presente artigo procura, mediante a descrição de um caso clínico sucedido no Hospital Militar Central de Bogotá, fazer uma revisão da literatura a respeito da doença, ressaltando os mecanismos fisiopatológicos, a detecção por diferentes provas de laboratório, bem como as estratégias de tratamento, demonstrando que graças aos progressos realizados em seu entendimento e enfoque, atualmente se pode falar de evitar a mortalidade, atingindo em muitos casos, uma sobrevida em longo prazo sem maiores seqüelas neurológicas, tudo isso com um manejo interdisciplinares que consiga um controle metabólico adequado...

Uso de cetoanálogo na terapia da insuficiência renal canina

The efficacy of keto acids and essential amino acids on a two-year-old female dog, Labrador, suffering from Leishmaniasis and acute renal failure was evaluated by clinical and laboratorial analyses based on urea and creatinine dosages. An improving in the animal general condition and an increasing in the appetite, activity and weight gain, were observed and favorably contributed to the treatment of the primary disease. Ketoanalogueswere oraly administered during 76 days and the levels of urea and creatinine remained within acceptable limits, even after this period of time. Ketoanaloguescontributed positively for the treatment of acute renal failure and appears to be an important alternative for the leishmaniasis treatment.