Basal forebrain cholinergic system in the dementias: Vulnerability, resilience, and resistance.

The basal forebrain cholinergic neurons (BFCN) provide the primary source of cholinergic innervation of the human cerebral cortex. They are involved in the cognitive processes of learning, memory, and attention. These neurons are differentially vulnerable in various neuropathologic entities that cause dementia. This review summarizes the relevance to BFCN of neuropathologic markers associated with dementias, including the plaques and tangles of Alzheimer's disease (AD), the Lewy bodies of diffuse Lewy body disease, the tauopathy of frontotemporal lobar degeneration (FTLD-TAU) and the TDP-43 proteinopathy of FTLD-TDP. Each of these proteinopathies has a different relationship to BFCN and their corticofugal axons. Available evidence points to early and substantial degeneration of the BFCN in AD and diffuse Lewy body disease. In AD, the major neurodegenerative correlate is accumulation of phosphotau in neurofibrillary tangles. However, these neurons are less vulnerable to the tauopathy of FTLD. An intriguing finding is that the intracellular tau of AD causes destruction of the BFCN, whereas that of FTLD does not. This observation has profound implications for exploring the impact of different species of tauopathy on neuronal survival. The proteinopathy of FTLD-TDP shows virtually no abnormal inclusions within the BFCN. Thus, the BFCN are highly vulnerable to the neurodegenerative effects of tauopathy in AD, resilient to the neurodegenerative effect of tauopathy in FTLD and apparently resistant to the emergence of proteinopathy in FTLD-TDP and perhaps also in Pick's disease. Investigations are beginning to shed light on the potential mechanisms of this differential vulnerability and their implications for therapeutic intervention.

Focal white matter lesions induce long-lasting axonal degeneration, neuroinflammation and behavioral deficits.

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) with episodes of inflammatory demyelination and remyelination. While remyelination has been linked with functional recovery in MS patients, there is evidence of ongoing tissue damage despite complete myelin repair. In this study, we investigated the long-term consequences of an acute demyelinating white matter CNS lesion. For this purpose, acute demyelination was induced by 5-week-cuprizone intoxication in male C57BL/6 J mice, and the tissues were examined after a 7-month recovery period. While myelination and oligodendrocyte densities appeared normal, ongoing axonal degeneration and glia cell activation were found in the remyelinated corpus callosum. Neuropathologies were paralleled by subtle gait abnormalities evaluated using DigiGait™ high speed ventral plane videography. Gene array analyses revealed increased expression levels of various inflammation related genes, among protein kinase c delta (PRKCD). Immunofluorescence stains revealed predominant microglia/macrophages PRKCD expression in both, cuprizone tissues and post-mortem MS lesions. These results support the hypothesis that chronic microglia/macrophages driven tissue injury represents a key aspect of progressive neurodegeneration and functional decline in MS.

Fundamental Clock of Biological Aging: Convergence of Molecular, Neurodegenerative, Cognitive and Psychiatric Pathways: Non-Equilibrium Thermodynamics Meet Psychology.

In humans, age-associated degrading changes, widely observed in molecular and cellular processes underly the time-dependent decline in spatial navigation, time perception, cognitive and psychological abilities, and memory. Cross-talk of biological, cognitive, and psychological clocks provides an integrative contribution to healthy and advanced aging. At the molecular level, genome, proteome, and lipidome instability are widely recognized as the primary causal factors in aging. We narrow attention to the roles of protein aging linked to prevalent amino acids chirality, enzymatic and spontaneous (non-enzymatic) post-translational modifications (PTMs SP), and non-equilibrium phase transitions. The homochirality of protein synthesis, resulting in the steady-state non-equilibrium condition of protein structure, makes them prone to multiple types of enzymatic and spontaneous PTMs, including racemization and isomerization. Spontaneous racemization leads to the loss of the balanced prevalent chirality. Advanced biological aging related to irreversible PTMs SP has been associated with the nontrivial interplay between somatic (molecular aging) and mental (psychological aging) health conditions. Through stress response systems (SRS), the environmental and psychological stressors contribute to the age-associated "collapse" of protein homochirality. The role of prevalent protein chirality and entropy of protein folding in biological aging is mainly overlooked. In a more generalized context, the time-dependent shift from enzymatic to the non-enzymatic transformation of biochirality might represent an important and yet underappreciated hallmark of aging. We provide the experimental arguments in support of the racemization theory of aging.

Deletion of exons encoding carboxypeptidase domain of Nna1 results in Purkinje cell degeneration (pcd) phenotype.

Purkinje cell degeneration (pcd) was first identified in a spontaneous mouse mutant showing cerebellar ataxia. In addition to cerebellar Purkinje cells (PCs), retinal photoreceptors, mitral cells in the olfactory bulb, and a discrete subpopulation of thalamic neurons also degenerate in the mutant brains. The gene responsible for the pcd mutant is Nna1, also known as ATP/GTP binding protein 1 or cytosolic carboxypeptidase-like 1, which encodes a zinc carboxypeptidase protein. To investigate pathogenesis of the pcd mutation in detail, we generated a conditional Nna1 allele targeting the carboxypeptidase domain at C-terminus. After Cre recombination and heterozygous crossing, we generated Nna1 knockout (KO) mice and found that the Nna1 KO mice began to show cerebellar ataxia at postnatal day 20 (P20). Most PCs degenerated until 4-week-old, except lobule X. Activated microglia and astrocytes were also observed in the Nna1 KO cerebellum. In the mutant brain, the Nna1 mRNA level was dramatically reduced, suggesting that nonsense-mediated mRNA decay occurs in it. Since the Nna1 protein acts as a de-glutamatase on the C-terminus of α-tubulin and ß-tubulin, increased polyglutamylated tubulin was detected in the Nna1 KO cerebellum. In addition, the endoplasmic reticulum stress marker, C/EBP homologous protein (CHOP), was up-regulated in the mutant PCs. We report the generation of a functional Nna1 conditional allele and possible mechanisms of PC death in the Nna1 KO in the cerebellum. OPEN PRACTICES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.

Cognitive reserve maps the core loci of neurodegeneration in corticobasal degeneration.

BACKGROUND AND PURPOSE: Cognitively stimulating life experiences and activities are deemed to moderate the clinical impact of brain damage progressively building a neural and cognitive reserve (CR). CR has been studied extensively in various neurodegenerative disorders, but not in corticobasal degeneration (CBD). METHODS: Using Statistical Parametric Mapping 8, years of education, as a determinant of CR, was correlated with tracer uptake on positron emission tomography with 18 F-fluorodeoxyglucose, as a marker of neurodegeneration, in 35 patients with various phenotypes of CBD, including a cognitive-motor composite score or symptoms duration as covariates for controlling disease stage. RESULTS: A cluster of relative hypometabolism was found associated with higher education in the left inferior regions of pre- and post-rolandic gyri and insula, which represent typical loci of neurodegeneration in CBD regardless of clinical presentation. CONCLUSIONS: The present findings extend to CBD the evidence gathered in other neurodegenerative disorders that a higher CR has a protective effect against the clinical manifestations of brain degeneration.

Systemic TNF-α produces acute cognitive dysfunction and exaggerated sickness behavior when superimposed upon progressive neurodegeneration.

Inflammation influences chronic neurodegeneration but its precise roles are not yet clear. Systemic inflammation caused by infection, trauma or co-morbidity can alter the brain's inflammatory status, produce acute cognitive impairments, such as delirium, and drive new pathology and accelerated decline. Consistent with this, elevated systemic TNF-α is associated with more rapid cognitive decline over 6months in Alzheimer's disease patients. In the current study we challenged normal animals and those with existing progressive neurodegeneration (ME7 prion disease) with TNF-α (i.p.) to test the hypothesis that this cytokine has differential effects on cognitive function, sickness behavior and features of underlying pathology contingent on the animals' baseline condition. TNF-α (50µg/kg) had no impact on performance of normal animals (normal brain homogenate; NBH) on working memory (T-maze) but produced acute impairments in ME7 animals similarly challenged. Plasma TNF-α and CCL2 levels were equivalent in NBH and ME7 TNF-challenged animals but hippocampal and hypothalamic transcription of IL-1ß, TNF-α and CCL2 and translation of IL-1ß were higher in ME7+TNF-α than NBH+TNF-α animals. TNF-α produced an exaggerated sickness behavior response (hypothermia, weight loss, inactivity) in ME7 animals compared to that in NBH animals. However a single challenge with this dose was not sufficient to produce de novo neuronal death, synaptic loss or tau hyperphosphorylation that was distinguishable from that arising from ME7 alone. The data indicate that acutely elevated TNF-α has robust acute effects on brain function, selectively in the degenerating brain, but more sustained levels may be required to significantly impact on underlying neurodegeneration.

Cognitive performance correlates with the degree of dopaminergic degeneration in the associative part of the striatum in non-demented Parkinson's patients.

Parkinson's disease (PD) patients show cognitive deficits that are relevant in terms of prognosis and quality of life. Degeneration of striatal dopaminergic afferents proceeds from dorsal/caudal to anterior/ventral and is discussed to account for some of these symptoms. Treatment with dopamine (DA) has differential effects on cognitive dysfunctions, improving some and worsening others. We hypothesized that cognitive performance during the dopaminergic OFF state correlates with DAT availability in the associative striatum. 16 PD patients underwent motor and cognitive examination ON and OFF DA. Global cognition was measured using the Montréal Cognitive Assessment (MoCA) test and executive functioning using a Stroop test. Nigrostriatal dopaminergic innervation was characterized with [123I]FP-CIT SPECT. A connectivity atlas of the striatum was used to assess DAT availability in functionally defined striatal subregions. Correlations between imaging data and behavioral data OFF medication were calculated. Correlations between DAT availability and MoCA performance in the dopaminergic OFF state was strongest in the associative part of the striatum (r = 0.674, p = 0.004). MoCA test performance did not differ between the ON and the OFF state. There was no correlation of DAT availability with Stroop performance in the OFF state but performance was significantly better during the ON state. Not only motor but also cognitive dysfunctions in PD are associated with striatal dopaminergic depletion. Cognitive decline in non-demented PD patients goes along with nigrostriatal degeneration, most pronounced in the associative subdivision of the striatum. In addition, the present findings suggest that executive dysfunctions are ameliorated by DA whereas global cognition is not improved by dopaminergic medication.

Synthesis and neuroprotective effects of the complex nanoparticles of iron and sapogenin isolated from the defatted seeds of Camellia oleifera.

CONTEXT: The defatted seeds of Camellia oleifera var. monosperma Hung T. Chang (Theaceae) are currently discarded without effective utilization. However, sapogenin has been isolated and shows antioxidative, anti-inflammatory and analgesic activities suggestive of its neuroprotective function. OBJECTIVE: In order to improve the activities of sapogenin, the nanoparticles of iron-sapogenin have been synthesized, and the neuroprotective effects are evaluated. MATERIALS AND METHODS: Structural characters of the nanoparticles were analyzed, and the antioxidant effect was assessed by DPPH method, and the neuroprotective effect was evaluated by rotenone-induced neurodegeneration in Kunming mice injected subcutaneously into the back of neck with rotenone (50 mg/kg/day) for 6 weeks and then treated by tail intravenous injection with the iron-sapogenin at the dose of 25, 50 and 100 mg/kg for 7 days. Mice behaviour and neurotransmitters were tested. RESULTS: The product had an average size of 162 nm with spherical shape, and scavenged more than 90% DPPH radicals at 0.8 mg/mL concentration. It decreased behavioural disorder and malondialdehyde content in mice brain, and increased superoxide dismutase activity, tyrosine hydroxylase expression, dopamine and acetylcholine levels in brain in dose dependence, and their maximum changes were respectively up to 60.83%, 25.17%, 22.13%, 105.26%, 42.17% and 22.89% as compared to vehicle group. Iron-sapogenin nanoparticle shows significantly better effects than the sapogenin. DISCUSSION AND CONCLUSION: Iron-sapogenin alleviates neurodegeneration of mice injured by neurotoxicity of rotenone, it is a superior candidate of drugs for neuroprotection.

Postischemic Anhedonia Associated with Neurodegenerative Changes in the Hippocampal Dentate Gyrus of Rats.

Poststroke depression is one of the major symptoms observed in the chronic stage of brain stroke such as cerebral ischemia. Its pathophysiological mechanisms, however, are not well understood. Using the transient right middle cerebral artery occlusion- (MCAO-, 90 min) operated rats as an ischemia model in this study, we first observed that aggravation of anhedonia spontaneously occurred especially after 20 weeks of MCAO, and it was prevented by chronic antidepressants treatment (imipramine or fluvoxamine). The anhedonia specifically associated with loss of the granular neurons in the ipsilateral side of hippocampal dentate gyrus and was also prevented by an antidepressant imipramine. Immunohistochemical analysis showed increased apoptosis inside the granular cell layer prior to and associated with the neuronal loss, and imipramine seemed to recover the survival signal rather than suppressing the death signal to prevent neurons from apoptosis. Proliferation and development of the neural stem cells were increased transiently in the subgranular zone of both ipsi- and contralateral hippocampus within one week after MCAO and then decreased and almost ceased after 6 weeks of MCAO, while chronic imipramine treatment prevented them partially. Overall, our study suggests new insights for the mechanistic correlation between poststroke depression and the delayed neurodegenerative changes in the hippocampal dentate gyrus with effective use of antidepressants on them.

The Spontaneous Ataxic Mouse Mutant Tippy is Characterized by a Novel Purkinje Cell Morphogenesis and Degeneration Phenotype.

This study represents the first detailed analysis of the spontaneous neurological mouse mutant, tippy, uncovering its unique cerebellar phenotype. Homozygous tippy mutant mice are small, ataxic, and die around weaning. Although the cerebellum shows grossly normal foliation, tippy mutants display a complex cerebellar Purkinje cell phenotype consisting of abnormal dendritic branching with immature spine features and patchy, non-apoptotic cell death that is associated with widespread dystrophy and degeneration of the Purkinje cell axons throughout the white matter, the cerebellar nuclei, and the vestibular nuclei. Moderate anatomical abnormalities of climbing fiber innervation of tippy mutant Purkinje cells were not associated with changes in climbing fiber-EPSC amplitudes. However, decreased ESPC amplitudes were observed in response to parallel fiber stimulation and correlated well with anatomical evidence for patchy dark cell degeneration of Purkinje cell dendrites in the molecular layer. The data suggest that the Purkinje neurons are a primary target of the tippy mutation. Furthermore, we hypothesize that the Purkinje cell axonal pathology together with disruptions in the balance of climbing fiber and parallel fiber-Purkinje cell input in the cerebellar cortex underlie the ataxic phenotype in these mice. The constellation of Purkinje cell dendritic malformation and degeneration phenotypes in tippy mutants is unique and has not been reported in any other neurologic mutant. Fine mapping of the tippy mutation to a 2.1 MB region of distal chromosome 9, which does not encompass any gene previously implicated in cerebellar development or neuronal degeneration, confirms that the tippy mutation identifies novel biology and gene function.

Cortical cholinergic input is required for normal auditory perception and experience-dependent plasticity in adult ferrets.

The nucleus basalis (NB) in the basal forebrain provides most of the cholinergic input to the neocortex and has been implicated in a variety of cognitive functions related to the processing of sensory stimuli. However, the role that cortical acetylcholine release plays in perception remains unclear. Here we show that selective loss of cholinergic NB neurons that project to the cortex reduces the accuracy with which ferrets localize brief sounds and prevents them from adaptively reweighting auditory localization cues in response to chronic occlusion of one ear. Cholinergic input to the cortex was disrupted by making bilateral injections of the immunotoxin ME20.4-SAP into the NB. This produced a substantial loss of both p75 neurotrophin receptor (p75(NTR))-positive and choline acetyltransferase-positive cells in this region and of acetylcholinesterase-positive fibers throughout the auditory cortex. These animals were significantly impaired in their ability to localize short broadband sounds (40-500 ms in duration) in the horizontal plane, with larger cholinergic cell lesions producing greater performance impairments. Although they localized longer sounds with normal accuracy, their response times were significantly longer than controls. Ferrets with cholinergic forebrain lesions were also less able to relearn to localize sound after plugging one ear. In contrast to controls, they exhibited little recovery of localization performance after behavioral training. Together, these results show that cortical cholinergic inputs contribute to the perception of sound source location under normal hearing conditions and play a critical role in allowing the auditory system to adapt to changes in the spatial cues available.

Callosal degeneration topographically correlated with cognitive function in amnestic mild cognitive impairment and Alzheimer's disease dementia.

Degeneration of the corpus callosum (CC) is evident in the pathogenesis of Alzheimer's disease (AD). However, the correlation of microstructural damage in the CC on the cognitive performance of patients with amnestic mild cognitive impairment (aMCI) and AD dementia is undetermined. We enrolled 26 normal controls, 24 patients with AD dementia, and 40 single-domain aMCI patients with at least grade 1 hippocampal atrophy and isolated memory impairment. Diffusion tensor imaging (DTI) with fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (DA), and radial diffusivity (DR) were measured. The entire CC was parcellated based on fiber trajectories to specific cortical Brodmann areas using a probabilistic tractography method. The relationship between the DTI measures in the subregions of the CC and cognitive performance was examined. Although the callosal degeneration in the patients with aMCI was less extended than in the patients with AD dementia, degeneration was already exhibited in several subregions of the CC at the aMCI stage. Scores of various neuropsychological tests were correlated to the severity of microstructural changes in the subregional CC connecting to functionally corresponding cortical regions. Our results confirm that CC degeneration is noticeable as early as the aMCI stage of AD and the disconnection of the CC subregional fibers to the corresponding Brodmann areas has an apparent impact on the related cognitive performance.

Much of late life cognitive decline is not due to common neurodegenerative pathologies.

OBJECTIVE: The pathologic indices of Alzheimer disease, cerebrovascular disease, and Lewy body disease accumulate in the brains of older persons with and without dementia, but the extent to which they account for late life cognitive decline remains unknown. We tested the hypothesis that these pathologic indices account for the majority of late life cognitive decline. METHODS: A total of 856 deceased participants from 2 longitudinal clinical-pathologic studies, Rush Memory and Aging Project and Religious Orders Study, completed a mean of 7.5 annual evaluations, including 17 cognitive tests. Neuropathologic examinations provided quantitative measures of global Alzheimer pathology, amyloid load, tangle density, macroscopic infarcts, microinfarcts, and neocortical Lewy bodies. Random coefficient models were used to examine the linear relation of pathologic indices with global cognitive decline. In subsequent analyses, random change point models were used to examine the relation of the pathologic indices with the onset of terminal decline and rates of preterminal and terminal decline (ie, nonlinear decline). RESULTS: Cognition declined a mean of about 0.11 U per year (estimate = -0.109, standard error [SE] = 0.004, p < 0.001), with significant individual differences in rates of decline; the variance estimate for the individual slopes was 0.013 (SE = 0.112, p < 0.001). In separate analyses, global Alzheimer pathology, amyloid, tangles, macroscopic infarcts, and neocortical Lewy bodies were associated with faster rates of decline and explained 22%, 6%, 34%, 2%, and 8% of the variation in decline, respectively. When analyzed simultaneously, the pathologic indices accounted for a total of 41% of the variation in decline, and the majority remained unexplained. Furthermore, in random change point models examining the influence of the pathologic indices on the onset of terminal decline and the preterminal and terminal components of the cognitive trajectory, the common pathologic indices accounted for less than a third of the variation in the onset of terminal decline and rates of preterminal and terminal decline. INTERPRETATION: The pathologic indices of the common causes of dementia are important determinants of cognitive decline in old age and account for a large proportion of the variation in late life cognitive decline. Surprisingly, however, much of the variation in cognitive decline remains unexplained, suggesting that other important determinants of cognitive decline remain to be identified. Identification of the mechanisms that contribute to the large unexplained proportion of cognitive decline is urgently needed to prevent late life cognitive decline.

Beyond and below the cortex: the contribution of striatal dysfunction to cognition and behaviour in neurodegeneration.

Investigations of cognitive and behavioural changes in neurodegeneration have been mostly focussed on how cortical changes can explain these symptoms. In the proposed review, we will argue that the striatum has been overlooked as a critical nexus in understanding the generation of such symptoms. Although the striatum is historically more associated with motor dysfunction, there is increasing evidence from functional neuroimaging studies in the healthy that striatal regions modulate behaviour and cognition. This should not be surprising, as the striatum has strong anatomical connections to many cortical regions including the frontal, temporal and insula lobes, as well as some subcortical regions (amygdala, hippocampus). To date, however, it is largely unclear to what extent striatal regions are affected in many neurodegenerative conditions-and if so, how striatal dysfunction can potentially influence cognition and behaviour. The proposed review will examine the existing evidence of striatal changes across selected neurodegenerative conditions (Parkinson's disease, progressive supranuclear palsy, Huntington's disease, motor neuron disease, frontotemporal dementia and Alzheimer's disease), and will document their link with the cognitive and behavioural impairments observed. Thus, by reviewing the varying degrees of cortical and striatal changes in these conditions, we can start outlining the contributions of the striatal nexus to cognitive and behavioural symptoms. In turn, this knowledge will inform future studies investigating corticostriatal networks and also diagnostic strategies, disease management and future therapeutics of neurodegenerative conditions.

Cerebrospinal fluid biomarkers of neurodegeneration in patients with juvenile and classic myotonic dystrophy type 1.

BACKGROUND AND PURPOSE: The aim of the present study was to analyze cerebrospinal fluid (CSF) levels of total tau (T-tau), phosphorylated tau (P-tau) and the 42-amino-acid form of ß-amyloid (Aß42 ) in patients with myotonic dystrophy type 1 (DM1), and their possible correlations with cognitive and behavioral manifestations in these patients. METHODS: Lumbar puncture was performed in 74 patients with DM1 [27 with the childhood/juvenile form (jDM1) and 47 with the adult form (aDM1) of the disease] and 26 control subjects who were subjected to orthopedic surgery. Sandwich ELISA was used for measuring the levels of T-tau, P-tau and Aß42. RESULTS: The CSF level of Aß42 was at its lowest in patients with jDM1 and at its highest in controls (P < 0.05). A tendency of T-tau and P-tau to increase was greater in aDM1 patients than in jDM1 patients and controls (P > 0.05). In both jDM1 and aDM1 patients, significant correlations were found between Aß42 and T-tau (rho = 0.81 and rho = 0.67, respectively, P < 0.01), as well as between Aß42 and P-tau (rho = 0.87 and rho = 0.67, respectively, P < 0.01). The Aß42/P-tau ratio decreased with age in aDM1 patients (rho = -0.30, P < 0.05). Only the level of Aß42 in the CSF of jDM1 patients was correlated with the size of the CTG expansion (rho = -0.53, P < 0.05). Only a few correlations were observed between levels of biomarkers and neuropsychological testing. CONCLUSION: The CSF level of Aß42 was decreased in patients with jDM1, whilst the Aß42/P-tau ratio was decreased in aDM1 patients. Positive correlations between Aß42 , T-tau and P-tau were observed in both forms of disease. Further studies with larger cohorts of DM1 patients are necessary.

Mild cognitive impairment in patients with Parkinson's disease is associated with increased cortical degeneration.

Mild cognitive impairment (MCI) can occur early in the course of Parkinson's disease (PD), and its presence increases the risk of developing dementia. Determining the cortical changes associated with MCI in PD, thus, may be useful in predicting the future development of dementia. To address this objective, 37 patients with PD, divided into 2 groups according to the presence or absence MCI (18 with and 19 without) and 16 matched controls, underwent anatomic magnetic resonance imaging. Corticometry analyses were performed to measure the changes in cortical thickness and surface area as well as their correlation with disease duration. Compared with healthy controls, the PD-MCI group exhibited increased atrophy and changes of local surface area in the bilateral occipital, left temporal, and frontal cortices; whereas the PD non-MCI group exhibited only unilateral thinning and decreased surface area in the occipital lobe and in the frontal cortex. In addition, a comparison between the PD-MCI and PD non-MCI groups revealed increased local surface area in the occipital lobe, temporal lobe, and postcentral gyrus for the cognitively impaired patients. It is noteworthy that, in the PD-MCI group, cortical thickness had a significant negative correlation with disease duration in the precentral, supramarginal, occipital, and superior temporal cortices; whereas, in the PD non-MCI group, such a correlation was absent. The findings from this study reveal that, at the same stage of PD evolution, the presence of MCI is associated with a higher level of cortical changes, suggesting that cortical degeneration is increased in patients with PD because of the presence of MCI.

Low cerebrospinal fluid sulfatide predicts progression of white matter lesions: The LADIS study.

BACKGROUND/AIMS: Demyelination and axonal degeneration are the hallmarks of established white matter lesions (WML). The neurochemistry of ongoing WML is only partially known. We explored cerebrospinal fluid (CSF) substances as markers of brain tissue damage in relation to progression of WML rated on magnetic resonance imaging. METHODS: CSF from elderly individuals with WML was analyzed for amyloid markers, total τ, hyperphosphorylated τ, neurofilament protein light subunit, sulfatide and CSF/serum-albumin ratio. After 3 years, a follow-up magnetic resonance imaging was performed. Progression of WML was rated using the Rotterdam Progression Scale (RPS). RESULTS: 37 subjects (age 73.6 ± 4.6 years) were included. Subjects with more pronounced progression (RPS > 2; n = 15) had lower mean sulfatide concentration at baseline as compared to subjects with no or minimal progression (RPS 0-2; n = 22) according to univariate analyses (p = 0.009). Sulfatide was the only biomarker that predicted the RPS score according to regression analysis, explaining 18.9% of the total variance (r = 0.38, p = 0.015). CONCLUSION: The correlation of CSF sulfatide levels and RPS scores may reflect a remyelination response to the demyelination process associated with WML. Furthermore, the results strengthen the notion that WML pathology is different from that of Alzheimer's disease.

Phenotypic variation of autosomal-dominant corticobasal degeneration.

Neurodegenerative tauopathies may be inherited as autosomal-dominant disorders with variable clinicopathological phenotypes, and causative mutations in the microtubule-associated protein tau (MAPT) gene are not regularly seen. Herein, we describe a patient with clinically typical and autopsy-proven corticobasal degeneration (CBD). Her mother was diagnosed to have Parkinson's disease, but autopsy showed CBD pathology as in the index patient. The sister of the index patient had the clinical symptoms of primary progressive aphasia (PPA), but no pathology was available to date. Molecular analysis did not reveal any mutation in the MAPT or progranulin (GRN) genes. Our findings illustrate that CBD, progressive supranuclear palsy and PPA may be overlapping diseases with a common pathological basis rather than distinct entities. Clinical presentation and course might be determined by additional, yet unknown, genetic modifying factors.

Urinary 8-OHdG elevations in a partial lesion rat model of Parkinson's disease correlate with behavioral symptoms and nigrostriatal dopaminergic depletion.

Increased oxidative stress contributes to pathogenesis of Parkinson's disease (PD). 8-hydroxy-2'-deoxyguanosine (8-OHdG) is the oxidation product most frequently measured as an indicator of oxidative DNA damage. Several studies have shown increased 8-OHdG in PD patients. There are few basic laboratory data examining 8-OHdG levels in animal models of PD. In this study, we utilized hemiparkinsonian model of rats induced by intrastriatal injection of 6-hydroxydopamine (6-OHDA). The urinary 8-OHdG level was measured in relation to behavioral and pathological deficits arising from 6-OHDA-induced neurotoxic effects on the nigrostriatal dopaminergic pathway. All rats were subjected to a series of behavioral tests for 42 days after 6-OHDA injection. We collected urine samples with subsequent measurement of 8-OHdG level using ELISA kits. For immunohistochemical evaluation, tyrosine hydroxylase (TH) staining was performed. Significant increments in urinary 8-OHdG level were observed continuously from day 7 until day 35 compared to control group, which showed a trend of elevation as early as day 3. Such elevated urinary 8-OHdG level significantly correlated with all of the behavioral deficits measured here, suggesting that urinary 8-OHdG level provides a good index of severity of parkinsonism. Urinary 8-OHdG level also had a significant positive correlation with the survival rate of dopaminergic fibers or neurons, advancing the concept that oxidative stress during the early phase of 6-OHDA neurotoxicity may correspond to disease progression closely approximating neuronal degeneration in the nigrostriatal dopaminergic system. The present results demonstrate that alterations in urinary 8-OHdG level closely approximate onset and disease progression in PD.

Sominone improves memory impairments and increases axonal density in Alzheimer's disease model mice, 5XFAD.

Previously we showed that steroidal sapogenin, sominone improved memory after a single i.p. injection into normal mice. However, it had not been reported that sominone could recover memory deficits in a severe Alzheimer's disease (AD) model animal. Therefore, we aimed to investigate that sominone improved memory impairments in the 5XFAD mouse, model for AD. In the current study, we used sominone that we had synthesized. 5XFAD mice were given 10 µmol/kg sominone intraperitoneally for 9 days. In addition to object recognition memory, axonal density, amyloid plaque number, and activated microglia in the brain were evaluated. Sominone treatment significantly improved object recognition memory compared with vehicle control treatment. Sominone treatment significantly enhanced axonal densities in the frontal cortex and parietal cortex but had no effects on amyloid plaque number and activated microglia. In cultured cortical neurons, the axonal length was significantly reduced by Aß(1-42) treatment. However, that was markedly recovered 5 days after the treatment with 1 µM sominone. Neuronal loss was not observed in the cortex and hippocampus of 5XFAD mice at 6-8 months of age. These results suggest that memory deficits in AD may be improved by sominone independently of reducing amyloid plaques and neuroinflammation.