Menkes disease: Oral administration of glyoxal-bis(N(4)-methylthiosemicarbazonato)-copper(II) rescues the macular mouse.

BACKGROUND: Menkes disease is a copper metabolism disorder caused by mutations in ATP7A, a copper-transporting P-type ATPase. In this study, oral copper supplementation via glyoxal-bis(N(4)-methylthiosemicarbazonato)-copper(II) (CuGTSM), a lipophilic copper complex, was investigated in male hemizygous macular (MoMl/y) mice, a mouse model of Menkes disease. METHODS: CuGTSM was administered by oral gavage on postnatal days 5, 8, 11, 17, 23, and 32. The copper levels in the organs and serum, copper-dependent enzyme activities in the brain, and ceruloplasmin (Cp) activity in the serum were measured at 15 days and 3 and 8 months of age. Histological analysis of the intestines and the rotarod test were also performed. RESULTS: CuGTSM treatment extended the lifespan of MoMl/y mice and partly restored the copper concentrations and cytochrome oxidase and DBH activities in the brain; however, the rotarod test showed impaired motor performance. The treatment also increased copper concentrations and Cp activity in the serum. In suckling MoMl/y mice, CuGTSM treatment transiently induced diarrhea accompanied by copper accumulation and altered villus morphology in the ileum. CONCLUSION: Oral administration of CuGTSM extended the lifespan of MoMl/y mice. Oral administration is attractive, but pharmaceutical studies are needed to reduce the adverse enteral effects.

Copper-trafficking efficacy of copper-pyruvaldehyde bis(N4- methylthiosemicarbazone) on the macular mouse, an animal model of Menkes disease.

BACKGROUND: Menkes disease (MD) is a disorder of copper transport caused by ATP7A mutations. Although parenteral copper supplements are partly effective in treating MD, the copper level in the brain remains insufficient, whereas copper accumulates in the kidney. We investigated the copper-trafficking efficacy of copper-pyruvaldehyde bis(N4-methylthiosemicarbazone) (Cu-PTSM), a lipophilic copper complex, in macular mice, an animal model of MD. METHODS: Macular mice were treated with cupric chloride (CuCl2) or Cu-PTSM on postnatal days 4, 10, and 17. At 4 wk of age, the copper levels in major organs and cytochrome oxidase (CO) activity in brain tissue were measured. Hematology, blood biochemistry, and urinary ß2-microglobulin (ß2-M) secretion were also assessed. RESULTS: The copper levels in the brains of the Cu-PTSM-treated group remained low, but CO activity in the cerebral and cerebellar cortices in the Cu-PTSM-treated group were higher than those in the CuCl2-treated group. There were no significant differences in hematological or biochemical findings or in urinary ß2-M secretion among the groups. CONCLUSION: Although the copper-trafficking efficacy of Cu-PTSM was limited, the improved CO activity in the brain suggests that Cu-PTSM delivered copper more effectively to neuronal CO than did CuCl2. Reduced renal copper accumulation may be beneficial in prolonged copper supplementation.

Beta-phenylethylamine inhibits K+ currents in neocortical neurons of the rat: a possible mechanism of beta-phenylethylamine-induced seizures.

beta-Phenylethylamine (beta-PEA), an endogenous amine synthesized in the brain, serves as a neuromodulator and is involved in the pathophysiology of various neurological disorders such as depression, schizophrenia, and attention-deficit hyperactivity disorder. beta-PEA fully exerts the physiological effects within the nanomolar concentration range via the trace amine receptors, but beta-PEA also causes convulsions at much higher concentrations via an as yet unknown mechanism. To investigate the electrophysiological mechanism by which beta-PEA induces convulsions, we examined the effect of beta-PEA on ionic currents passing through the cell membrane of dissociated rat cerebral cortical neurons, using a patch-clamp technique. The external application of beta-PEA suppressed ionic currents which continuously flowed when the membrane potential was held at -25 mV. The suppression was in a concentration-dependent manner and a half-maximal effective concentration was 540 muM. These currents suppressed by beta-PEA consisted of two K(+) currents: a time- and voltage-dependent K(+) current (M-current) and a leakage K(+) current. The suppression of the M-current reduces the efficacy of the current in limiting excessive neuronal firing, and the suppression of the leakage K(+) current can cause membrane depolarization and thus promote neuronal excitation. Reducing both of these currents in concert may produce neuronal seizing activity, which could conceivably underlie the convulsions induced by high-dose beta-PEA.

The effects of copper-histidine therapy on brain metabolism in a patient with Menkes disease: a proton magnetic resonance spectroscopic study.

We report on metabolic changes in the brain of a boy with Menkes disease. He was treated with parenteral copper (Cu)-histidine supplementation, from 5 months of age, and assessed with proton magnetic resonance spectroscopy ((1)H-MRS). The single-voxel (1)H-MRS before treatment revealed an accumulation of lactate and a reduced N-acetyl aspartate (NAA)/total creatine (tCr) ratio with a z-score of -3.0. During treatment, the lactate signal faded away, whereas the NAA signal gradually increased to a z-score of -1.5 at 120 days of treatment. The choline/tCr ratio did not deviate much initially (z-score +0.5), but the ratio increased markedly during treatment (z-score +4.8). Consequently, the Cu-histidine therapy initiated after the critical period still improved the neuronal metabolism, suggesting that some Cu was delivered to neurons. Nevertheless, the brain atrophy, impaired myelination, and severe neurological symptoms were not ameliorated.