Antidepressant treatment restores brain-derived neurotrophic factor (BDNF) serum levels and ameliorates motor function in parkinson's disease patients

Introduction

Depression is a common psychiatric disorder in Parkinson's disease (PD). It has been proposed that antidepressant drugs may bust brain production of trophic factors, such as brain-derived neurotrophic factor (BDNF) and glial cell derived neurotrophic factor (GDNF), an effect associated with improvement of clinical symptoms. However, BDNF and GDNF play also a role in the maintenance of dopaminergic neurons, which undergo to neuronal death during PD course.

Aims

Based on these findings we explored the hypothesis that PD depressed patients may have altered BDNF or GDNF serum levels and that antidepressant drugs may restore them and potentially have beneficial effects not only for depressive but also parkinsonian symptoms.

Methods

We measured by enzyme linked immunosorbent assay (ELISA) the serum levels of BDNF and GDNF in depressed PD patients, non depressed PD patients and healthy subjects and correlated them with clinical observations.

Results

We found:

(1)

Conclusion

Our data suggest that PD patients are characterized by a reduction of BDNF serum levels and that depression may exacerbate this effect and worse PD symptoms. It is proposed that association between anti-parkinsonian treatment and SSRI could be a good therapeutic chance not only for treating depression in PD but also for improving PD symptoms.

Colorimetric response to anions by a "robust" copper(II) complex of a [9]aneN3 pendant arm derivative: CN- and I- selective sensing

The 1 : 1 complex [Cu(L)](BF(4))(2)·MeCN (1) of the tetradentate ligand 1-(2-quinolinylmethyl)-1,4,7-triazacyclononane (L) selectively changes its colour in the presence of CN(-) in H(2)O and MeCN (without undergoing decomplexation from the macrocyclic ligand). The same complex in MeCN assumes different colours in the presence of CN(-) or I(-).

White matter changes in patients with hypoxic amnesia

A deficit of declarative memory is a common sequela after a hypoxic episode. While the role of gray matter changes (i.e., atrophy of hippocampal formation) as mainly responsible for memory loss has been emphasized, the role of the white matter damage has so far been neglected. The present study was aimed at evaluating whether white matter damage, within the neural circuitry responsible for declarative memory functioning, is present in anoxic patients. We assessed, by means of voxel-based morphometry, the integrity of white matter regions in five patients with hypoxic amnesia. When anoxic patients were compared to healthy controls, significantly less white matter density was detected in the fornix, anterior portion of the cingulum bundle and uncinate fasciculus bilaterally. We conclude that cerebral hypoxia may alter, together with the hippocampi, the integrity of white matter fibers throughout the memory-limbic system.

Regional brain atrophy and functional disconnection across Alzheimer's disease evolution

OBJECTIVE

To assess the contribution of regional grey matter (GM) atrophy and functional disconnection in determining the level of cognitive decline in patients with Alzheimer's disease (AD) at different clinical stages.

METHODS

Ten patients with amnesic mild cognitive impairment (a-MCI), 11 patients with probable AD and 10 healthy controls were recruited. T1 volumes were obtained from each subject and postprocessed according to an optimised voxel based morphometry protocol. Resting state functional MRI data were also collected from the same individuals and analysed to produce connectivity maps after identification of the default mode network (DMN) by independent component analysis.

RESULTS

Compared with healthy controls, both AD and a-MCI patients showed a similar regional pattern of brain disconnection between the posterior cingulate cortex (PCC) and the medial prefrontal cortex and the rest of the brain. Conversely, the distribution of GM atrophy was significantly more restricted in a-MCI than in AD patients. Interestingly, the PCC showed reduced connectivity in a-MCI patients in the absence of GM atrophy, which was, in contrast, detectable at the stage of fully developed AD.

CONCLUSIONS

This study indicates that disconnection precedes GM atrophy in the PCC, which is a critical area of the DMN, and supports the hypothesis that GM atrophy in specific regions of AD brains likely reflects a long term effect of brain disconnection. In this context, our study indicates that GM atrophy in PCC accompanies the conversion from MCI to AD.

Deep brain stimulation of the pedunculopontine tegmentum and subthalamic nucleus: effects on gait in Parkinson's disease

OBJECTIVE

This study examines the effects of subthalamic nucleus (STN) deep brain stimulation (DBS) and pedunculopontine tegmentum (PPTg) DBS in advanced Parkinson's disease using gait analysis.

METHODS

Five people underwent bilateral DBS in both the STN and PPTg. Gait analysis was performed one year after neurosurgery using an optoelectronic system. The effects of DBS (STN, PPTg and STN+PPTg) were studied in two clinical conditions: without (Off) and during (On) antiparkinsonian therapy.

RESULTS

PPTg and STN DBS were associated with changes in spatio-temporal and kinematics variables.

CONCLUSIONS

Although experimental data cannot be generalized widely due to the small sample, PPTg DBS appears to affect the neuronal circuits subserving gait.

When, where, and how the corpus callosum changes in MCI and AD: a multimodal MRI study

BACKGROUND

The corpus callosum (CC) has been shown to be susceptible to atrophy in Alzheimer disease (AD) as a correlate of wallerian degeneration or retrogenesis. However, when and where these 2 mechanisms intervene is still unclear.

METHODS

In 3 memory clinics, we recruited 38 patients with amnestic mild cognitive impairment (MCI), 38 patients with mild AD, and 40 healthy controls (HC). Combining voxel-based morphometry and diffusion tensor imaging, we investigated CC white matter (WM) density and fractional anisotropy (FA), radial diffusivity (DR), and axial diffusivity (DA).

RESULTS

Compared with HC, patients with amnestic MCI showed reduced WM density in the anterior CC subregion; however, FA, DR, and DA did not differ between the 2 groups. Significant changes were found in patients with mild AD compared with HC in the anterior and posterior CC regions. These differences were evident in both voxel-based morphometry and diffusion tensor imaging analyses. Specifically, we found reduced callosal WM density in the genu, posterior body, and splenium; decreased FA and increased DR in the anterior CC subregion; and increased DA, with no difference in the FA, in the posterior CC subregion.

CONCLUSIONS

Callosal changes are already present in patients with amnestic mild cognitive impairment (MCI) and mild Alzheimer disease (AD). The precocious involvement of the anterior callosal subregion in amnestic MCI extends to posterior regions in mild AD. Two different mechanisms might contribute to the white matter changes in mild AD: wallerian degeneration in posterior subregions of the corpus callosum (suggested by increased axial diffusivity without fractional anisotropy modifications) and a retrogenesis process in the anterior callosal subregions (suggested by increased radial diffusivity without axial diffusivity modifications).

A selective, nontoxic, OFF-ON fluorescent molecular sensor based on 8-hydroxyquinoline for probing Cd(2+) in living cells

In spite of the fact that cadmium(II) has been recognized as a highly toxic element and that excessive exposure to this metal ion has been reported to have many adverse effects on human health, very few selective and specific fluorescent probes are available for imaging Cd(2+) in living cells. Herein, we report the spectroscopic and photochemical characterization of 5-(5-chloro-8-hydroxyquinolinylmethyl)-2,8-dithia-5-aza-2,6-pyridinophane (L) as a fluorescent sensor for the selective imaging of Cd(2+) in living cells. In particular, the response of L to Cd(2+) was first assessed in aqueous solutions, sodium dodecyl sulfate micelles, and liposomes, and subsequently in living cells by fluorescence microscopy techniques. Cytofluorimetric analyses of leukemic HL-60 cells loaded with L also allowed evaluation of the toxicity of the probe and the selective analysis of its intracellular fluorescence in the presence of Cd(2+). Furthermore, the 1:1 complex species [Cd(L)H(2)O](2+) responsible for the OFF-ON chelation enhancement of fluorescence (CHEF) effect on L was structurally characterized; time-dependent DFT calculations allowed the prediction of theoretical excitations, which were comparable with the experimental ones.

Met158 variant of the catechol-O-methyltransferase genotype is associated with thicker cortex in adult brain

Cortical thickness has been proposed as a new promising brain imaging endophenotype in elucidating the nature of gene-brain relationships. Here, we define the morphological impact of the Val(158)Met polymorphism in the catechol-O-methyltransferase (COMT) gene on human brain anatomy. One hundred and forty-nine adult healthy subjects (mean age: 40.7+/-16.1; ranging from 19 to 76 years) were genotyped (38 in the homozygous Val(158) group; 80 in the Val(158)Met group; 31 in the homozygous Met(158) group) for the COMT polymorphism and underwent morphological examination. Surface-based analysis of the cortical mantle showed that the COMT genotype was associated with structural differences in the right superior temporal sulcus and inferior prefrontal sulcus, where the individuals carrying the Met(158) allele had a thicker cortex with respect to their Val(158) counterparts. Our study extends the previous evidence found on pediatric population to the adult population, demonstrating that the higher synaptic dopamine levels associated with the presence of the Met(158) allele may influence neuronal architecture in brain structures important for executive and emotional processing.

Bis-cation salt complexation by meso-octamethylcalix[4]pyrrole: linking complexes in solution and in the solid state

Pyridinium and imidazolium bis-cations are shown to link calix[4]pyrrole anion complexes both in solution and in the solid state. This is accomplished by binding of the bis-cations to the electron-rich bowl shaped cavities formed by two separate calixpyrrole-anion complexes. These resulting sandwich-type structures provide a new way of organising calix[4]pyrrole anion complexes in space.

Single domain amnestic MCI: a multiple cognitive domains fMRI investigation

Amnestic mild cognitive impairment (a-MCI) is associated with the highest annual incidence of conversion to Alzheimer's disease (AD) (10-15%). a-MCI patients may have only a memory deficit (single domain: sd-a-MCI) or additional dysfunctions affecting other cognitive domains (multiple domain: md-a-MCI). Using functional magnetic resonance imaging (fMRI), we investigated brain activation in 16 sd-a-MCI patients and 14 controls during four different tasks assessing language, memory, attention and empathy functions. We found greater activation in sd-a-MCI compared with controls in the left inferior temporal gyrus (language), the right superior temporal gyrus (memory) and the right dorsal precentral gyrus (attention). Moreover, patients' activation correlated significantly with neuropsychological scores obtained at tests exploring the corresponding function. These findings indicate that fMRI is sensitive to detect early changes occurring in AD pathology and that individuals with sd-a-MCI show increased activation in multiple task-related brain regions. We suggest that these functional changes relate to the development of early compensatory mechanisms that reduce cognitive deficits associated with the progressive accumulation of brain damage.

Quenching effect of some heavy metal ions on the fast peroxyoxalate-chemiluminescence of 1-(dansylamidopropyl)-1-aza-4,7,10-trithiacyclododecane as a novel fluorophore

The fast chemiluminescence (CL) arising from the reaction of bis(2,4,6-trichlorophenyl)oxalate (TCPO) with hydrogen peroxide in the presence of 1-(dansylamidopropyl)-1-aza-4,7,10-trithiacyclododecane (L) as a novel fluorophore, and imidazole as catalyst, has been studied in ethyl acetate solution. The relationships between the chemiluminescence intensity and concentrations of TCPO, imidazole, hydrogen peroxide and L are reported. In the presence of imidazole as catalyst, the entire CL signal was completed in less than 3s. The quenching effect of Cu(2+), Pb(2+), Cd(2+), Hg(2+) and Ag(+) ions on the chemiluminescent system was investigated, the resulting Stern-Volmer plots were obtained and the K(Q) values were calculated. It was found that the quenching effect of metal ions on the chemiluminescence of L decreases in the order Cu(2+)>Pb(2+)>Cd(2+)>Hg(2+)>Ag(+).

Cerebellar magnetic stimulation decreases levodopa-induced dyskinesias in Parkinson disease

BACKGROUND

The neural mechanisms and the circuitry involved in levodopa-induced dyskinesia (LID) are still partially obscure. LID can be considered the consequence of an abnormal pattern or code of activity that originates and is conveyed from the basal ganglia to the thalamus and the cortical motor areas. However, not only striatothalamocortical motor circuits but also other interconnected pathways could be implicated in its pathogenesis.

METHODS

In a series of experiments, we applied repetitive transcranial magnetic stimulation (rTMS) over the lateral cerebellum in a group of patients with advanced Parkinson disease, to investigate whether modulation of cerebellothalamocortical circuits by means of rTMS may result in a modification of a dyskinetic state induced by levodopa ingestion.

RESULTS

We found that a single session of cerebellar continuous theta burst stimulation (cTBS) was capable of transiently reducing LID. In the same patients, we observed that cerebellar cTBS changed the profile of activation of intracortical circuits in the contralateral primary motor cortex. Cerebellar cTBS reduced short intracortical inhibition and increased long intracortical inhibition, inducing a cortical reorganization that is associated with a reduction of LID. Furthermore, in another experiment, we observed that a 2-week course of bilateral cerebellar cTBS induced persistent clinical beneficial effects, reducing peak-dose LID for up to 4 weeks after the end of the daily stimulation period.

CONCLUSIONS

Our study demonstrates that cerebellar continuous theta burst stimulation has an antidyskinetic effect in Parkinson disease patients with levodopa-induced dyskinesia, possibly due to modulation of cerebellothalamocortical pathways.

Investigation of quantitative magnetisation transfer parameters of lesions and normal appearing white matter in multiple sclerosis

The aim of this study was to use quantitative magnetisation transfer (MT) imaging to assess the different pathological substrates of tissue damage in multiple sclerosis (MS) and examine whether the MT parameters may be used to explain the disability in relapsing remitting (RR) MS. Thirteen patients with RRMS and 14 healthy controls were prescribed conventional MRI and quantitative MT imaging at 3.0 T. A two-pool model of MT (where A refers to the free pool and B to the macromolecular pool) was fitted to the data yielding a longitudinal relaxation rate R(A), a relative size F of macromolecular pool, transverse relaxation times T(2) (A) and T(2) (B) for the two pools and a forward exchange rate RM(0) (B). The MT ratio (MTR) was also computed. The mean MT parameters of the normal appearing white matter (NAWM) and of lesions in patients, and of white matter in controls were estimated. MT parameters were significantly different between lesions and NAWM in patients, and between the NAWM and the white matter of controls (with the exception of T(2) (B) and the MTR). Two models were investigated using ordered logistic regression, with the expanded disability status scale (EDSS) as the dependent variable. In the first one, mean NAWM MT parameters and lesion load were entered as explanatory variables; in the second one, mean MT variables within lesions and lesion load were entered as explanatory variables. Unexpectedly, T(2) (B) was the parameter most significantly associated with EDSS in NAWM. This parameter might represent a weighted average of the relaxation times of spins with different molecular environments, and therefore its variation could indicate a change in the balance between subpopulations of macromolecular spins. Conversely, in lesions, RM(0) (B), T(2) (B), F, R(A), and lesion load significantly predicted disability only when combined together. This might reflect the complex interaction between demyelination, remyelination, gliosis, inflammation and axonal loss taking place within lesions.

Fluorescent carbazolylurea anion receptors

A series of fluorescent carbazolylurea base anion receptors have been synthesised that show a high affinity for oxo-anions (particularly bicarbonate and acetate). The fluorescence of dicarbazolylurea (1) is quenched upon addition of benzoate anions in DMSO-0.5% water.

Quantification of gray matter changes in the cerebral cortex after isolated cerebellar damage: a voxel-based morphometry study

There is growing evidence based on behavioral and functional imaging studies about the cerebellar involvement in the modulation of cognitive functions. However, it still remains to be clarified how the cerebellum interacts with brain regions sub-serving different cognitive domains. In this study we used magnetic resonance imaging (MRI) and voxel based morphometry (VBM) to investigate changes of cerebral gray matter (GM) density in 15 patients with a focal cerebellar damage (CD) compared to 15 healthy controls. T2-weighted scans and T1-weighted volumes were collected from each subject. With the exception of the cerebellar lesion, none of the patients showed any additional brain MRI abnormality. T1-volumes were analyzed by voxel-based morphometry. Consistent with their neuropsychological abnormalities, patients with right-CD compared to controls showed a reduction of GM density mainly involving the left frontal, parietal and temporal lobes. Conversely, patients with left-CD did not show any significant neuropsychological or cerebral GM abnormality. The present study indicates that specific GM changes may be detected in patients with isolated CD and cognitive dysfunction. We discuss the findings in terms of cerebellar influence on the neuronal networks involved in higher level functions of the association cortex.

The evaluation of anosognosia in stroke patients

BACKGROUND

Anosognosia in stroke patients showed a relevant detrimental effect on the rehabilitation course and patients' quality of life, especially in those with brain injury. Although a number of reliable scales for the assessment of anosognosia in stroke and traumatic brain injury have been developed, at present no single measure fully explores the multifaceted nature of the phenomenon.

METHOD

A PubMed search with appropriate terms was carried out in order to critically review the issue.

RESULTS

The main dimensions to consider in the investigation of anosognosia in brain-injured patients are (a) awareness of deficit and related functional implications, (b) modality specificity, (c) causal attribution, (d) expectations of recovery, (e) implicit knowledge and (f) differential diagnosis with psychological denial. Time elapsed from stroke, aetiology, laterality, aphasia and clinical complications may influence all these characteristics and must be taken into consideration. Finally, an adequate association of the anosognosia evaluation with other neuropsychological and behavioural aspects is relevant for a modern holistic approach to the patient.

CONCLUSIONS

This review is meant to stimulate the development of a new comprehensive assessment procedure for anosognosia in brain injury and particularly in stroke, in order to catch the multidimensionality of the phenomenon and to shape rehabilitation programmes suitable to the specific clinical features of every single patient.