Detection of increased scyllo-inositol in brain with magnetic resonance spectroscopy after dietary supplementation in Alzheimer's disease mouse models.

There is evidence that inositol isomers may help protect against formation of toxic fibrils of Abeta fragments in Alzheimer's disease mouse models. Scyllo-inositol is one of the more promising inositol isomers for the potential treatment of Alzheimer's disease (AD) and can be detected using MRS in human subjects. In this manuscript we demonstrate using MRS, in two different mouse models of AD (APP x PS1 and APP x PS1 x tau), that we could detect increased scyllo-inositol in the hippocampus and frontal cortex in mice fed water supplemented with 16.5 mg/L of scyllo-inositol equivalent to about 3.3 mg/kg/day. We used both brain extracts using solution MRS as well as intact brain tissue using high resolution magic angle spinning (HRMAS) to ensure that any membrane-associated scyllo-inositol would be detected. By brain extracts we detected a 3.0 fold increase in scyllo-inositol in the scyllo-fed AD mice compared to normal diet (p < 0.001). Using HRMAS we detected a 2.2-2.4-fold increase in scyllo-inositol (p < 0.001). Scyllo-inositol treatment was associated with an increase in glutamine in hippocampus. The concentrations of scyllo-inositol were higher in the hippocampus than in the frontal cortex. Mice have a smaller concentration of scyllo-inositol than humans (ca. 100 microM vs. 500 microM in humans). Given the ease with which scyllo-inositol can be measured in human MRS data with high signal to noise ratios, these data suggest that MRS will prove useful for evaluation of inositol treatment trials in AD subjects.

Anti-inflammatory treatment in AD mice protects against neuronal pathology.

Prior studies suggest that non-steroidal anti-inflammatory drugs (NSAIDs) may lower the incidence of Alzheimer's disease (AD) and delay onset or slow progression of symptoms in mouse models of AD. We examined the effects of chronic NSAID treatment in order to determine which elements of the pathological features might be ameliorated. We compared the effects of the NSAIDs ibuprofen and celecoxib on immunohistological and neurochemical markers at two different ages in APPxPS1 mice using measurements of amyloid plaque deposition, Abeta peptide levels, and neurochemical profiles using magnetic resonance spectroscopy (MRS). At 6 months of age, few neurochemical changes were observed between PSAPP mice and WT mice using MRS. Ibuprofen, but not celecoxib, treatment significantly decreased the Abeta(42/40) ratio in frontal cortex at 6 months, but overall amyloid plaque burden was unchanged. Consistent with prior findings in mouse models, at 17 months of age, there was a decrease in the neuronal markers NAA and glutamate and an increase in the astrocytic markers glutamine and myo-inositol in AD mice compared to WT. Ibuprofen provided significant protection against NAA and glutamate loss. Neither of the drugs significantly affected myo-inositol or glutamine levels. Both ibuprofen and celecoxib lowered plaque burden without a significant effect on Abeta(1-42) levels. NAA levels significantly correlated with plaque burden. These results suggest that selective NSAIDs (ibuprofen and possibly celecoxib) treatment can protect against the neuronal pathology.

Magnetic resonance spectroscopy of regional brain metabolite markers in FALS mice and the effects of dietary creatine supplementation.

We investigated the effects of disease progression on brain regional neurochemistry in a mutant mouse model of familial amyotrophic lateral sclerosis (FALS; the G93A model) using in vivo and in vitro magnetic resonance spectroscopy (MRS). There were numerous changes in the brain spectra that were brain region dependent. At early time points starting around 80 days of age there were increases in brain glutamate. At later time points there were more extensive changes including decreased N-acetyl aspartate and glutamate and increased glutamine, taurine and myo-inositol. The effects of the disease were most severe in spinal cord followed by medulla and then sensorimotor cortex. There were no changes noted in cerebellum as a control region. The effects of creatine supplementation in the diet (2%) were measured in wild-type and FALS animals in medulla, cerebellum and cortex. The increase in brain creatine was largest in cerebellum (25%) followed by medulla (11%) and then cortex (4%), reflecting the ordering of creatine kinase activity. There was a protective effect of creatine on N-acetyl aspartate loss in the medulla at late stages. Creatine supplementation had a positive effect on weight retention, leading to a 13% increase in weight between 120 and 130 days. MRS shows promise in monitoring multiple facets of neuroprotective strategies in ALS and ALS models.

Ibuprofen reduces Abeta, hyperphosphorylated tau and memory deficits in Alzheimer mice.

We examined the effects of ibuprofen on cognitive deficits, Abeta and tau accumulation in young triple transgenic (3xTg-AD) mice. 3xTg-AD mice were fed ibuprofen-supplemented chow between 1 and 6 months. Untreated 3xTg-AD mice showed significant impairment in the ability to learn the Morris water maze (MWM) task compared to age-matched wild-type (WT) mice. The performance of 3xTg-AD mice was significantly improved with ibuprofen treatment compared to untreated 3xTg-AD mice. Ibuprofen-treated transgenic mice showed a significant decrease in intraneuronal oligomeric Abeta and hyperphosphorylated tau (AT8) immunoreactivity in the hippocampus. Confocal microscopy demonstrated co-localization of conformationally altered (MC1) and early phosphorylated tau (CP-13) with oligomeric Abeta, and less co-localization of oligomeric Abeta and later forms of phosphorylated tau (AT8 and PHF-1) in untreated 3xTg-AD mice. Our findings show that prophylactic treatment of young 3xTg-AD mice with ibuprofen reduces intraneuronal oligomeric Abeta, reduces cognitive deficits, and prevents hyperphosphorylated tau immunoreactivity. These findings provide further support for intraneuronal Abeta as a cause of cognitive impairment, and suggest that pathological alterations of tau are associated with intraneuronal oligomeric Abeta accumulation.

Creatine therapy provides neuroprotection after onset of clinical symptoms in Huntington's disease transgenic mice.

While there have been enormous strides in the understanding of Huntington's disease (HD) pathogenesis, treatment to slow or prevent disease progression remains elusive. We previously reported that dietary creatine supplementation significantly improves the clinical and neuropathological phenotype in transgenic HD mice lines starting at weaning, before clinical symptoms appear. We now report that creatine administration started after onset of clinical symptoms significantly extends survival in the R6/2 transgenic mouse model of HD. Creatine treatment started at 6, 8, and 10 weeks of age, analogous to early, middle, and late stages of human HD, significantly extended survival at both the 6- and 8-week starting points. Significantly improved motor performance was present in both the 6- and 8-week treatment paradigms, while reduced body weight loss was only observed in creatine-supplemented R6/2 mice started at 6 weeks. Neuropathological sequelae of gross brain and neuronal atrophy and huntingtin aggregates were delayed in creatine-treated R6/2 mice started at 6 weeks. We show significantly reduced brain levels of both creatine and ATP in R6/2 mice, consistent with a bioenergetic defect. Oral creatine supplementation significantly increased brain concentrations of creatine and ATP to wild-type control levels, exerting a neuroprotective effect. These findings have important therapeutic implications, suggesting that creatine therapy initiated after diagnosis may provide significant clinical benefits to HD patients.

Reduced creatine kinase activity in transgenic amyotrophic lateral sclerosis mice.

Creatine (Cr), the substrate of the creatine kinase (CK) isoenzymes, was shown to be neuroprotective in several models of neurodegeneration, including amyotrophic lateral sclerosis (ALS). In order to investigate the mechanism of this beneficial effect, we determined CK activities and mitochondrial respiration rates in tissues from G93A transgenic mice, which overexpress a mutant form of human superoxide dismutase associated with familial ALS (FALS). While respiration rates of mitochondria from G93A transgenic or wild-type control mice isolated from spinal cord showed no difference, a significant and dramatic loss of CK activity could be detected in these tissues. In homogenates from spinal cord of G93A transgenic mice, CK activity decreased to 49% and in mitochondrial fractions to 67% compared to CK activities in wild-type control mice. Feeding the G93A transgenic mice with 2% Cr, the same tissues showed no statistically significant increase of CK activity compared to regular fed G93A transgenic mice. Experiments with isolated mitochondria, however, showed that Cr and adenosine triphosphate (ATP) protected mitochondrial CK activity against peroxynitrite-induced inactivation, which may play a role in tissue damage in neurodegeneration. Our data provide evidence for oxidative damage to the CK system in ALS, which may contribute to impaired energy metabolism and neurodegeneration.

Therapeutic effects of coenzyme Q10 and remacemide in transgenic mouse models of Huntington's disease.

There is substantial evidence that bioenergetic defects and excitotoxicity may play a role in the pathogenesis of Huntington's disease (HD). Potential therapeutic strategies for neurodegenerative diseases in which there is reduced energy metabolism and NMDA-mediated excitotoxicity are the administration of the mitochondrial cofactor coenzyme Q10 and the NMDA antagonist remacemide. We found that oral administration of either coenzyme Q10 or remacemide significantly extended survival and delayed the development of motor deficits, weight loss, cerebral atrophy, and neuronal intranuclear inclusions in the R6/2 transgenic mouse model of HD. The combined treatment, using coenzyme Q10 and remacemide together, was more efficacious than either compound alone, resulting in an approximately 32 and 17% increase in survival in the R6/2 and N171-82Q mice, respectively. Magnetic resonance imaging showed that combined treatment significantly attenuated ventricular enlargement in vivo. These studies further implicate defective energy metabolism and excitotoxicity in the R6/2 and N171-82Q transgenic mouse models of HD and are of interest in comparison with the outcome of a recent clinical trial examining coenzyme Q10 and remacemide in HD patients.