Zsigmond Tamás Kincses

Alterations in PACAP-38-like immunoreactivity in the plasma during ictal and interictal periods of migraine patients.

Background Recent studies on migraineurs and our own animal experiments have revealed that pituitary adenylate cyclase-activating polypeptide-38 (PACAP-38) has an important role in activation of the trigeminovascular system. The aim of this study was to determine the PACAP-38-like immunoreactivity (LI) in the plasma of healthy subjects, and parallel with the calcitonin gene-related peptide (CGRP)-LI in migraine patients in the ictal and interictal periods. Methods A total of 87 migraineurs and 40 healthy control volunteers were enrolled in the examination. Blood samples were collected from the cubital veins in both periods in 21 patients, and in either the ictal or the interictal period in the remaining 66 patients, and were analysed by radioimmunoassay. Results A significantly lower PACAP-38-LI was measured in the interictal plasma of the migraineurs as compared with the healthy control group (p < 0.011). In contrast, elevated peptide levels were detected in the ictal period relative to the attack-free period in the 21 migraineurs (pPACAP-38 < 0.001; pCGRP < 0.035) and PACAP-38-LI in the overall population of migraineurs (p < 0.009). A negative correlation was observed between the interictal PACAP-38-LI and the disease duration. Conclusion This is the first study that has provided evidence of a clear association between migraine phases (ictal and interictal) and plasma PACAP-38-LI alterations.

White matter microstructural alterations in migraine: A diffusion-weighted MRI study

Summary White matter disintegration, as measured by diffusion‐weighted MRI, is reported in migraineurs, and is speculated to be either a marker of possible white matter disintegration or maladaptive plasticity. Abstract Migraine is a common and disabling neurological disease. The pathomechanism that underlies the disorder is not entirely understood, and reliable biomarkers are missing. In the current analysis we looked for microstructural alterations of the brain white matter in migraine patients by means of diffusion‐weighted magnetic resonance imaging. The measurements were carried out with a novel approach based on fine‐tuned nonlinear registration and nonparametric permutation test in an alignment‐invariant tract representation (Tract‐Based Spatial Statistics). We found reduced fractional anisotropy in the right frontal white matter cluster of migraine patients. In the same region we also found increased mean diffusivity and increased radial diffusivity. The probabilistic tractography showed connection of this cluster to other parts of the pain network (orbitofrontal cortex, insula, thalamus, dorsal midbrain). We speculate that these findings reflect maladaptive plastic changes or white matter disintegration.

Kynurenines, neurodegeneration and Alzheimer's disease.

•  Alzheimer’s disease •  The kynurenine pathway ‐  Neuroactive kynurenines ‐  Enzymes of the kynurenine pathway •  Relations of kynurenines to the pathomechanism of AD ‐  Altered activation of the kynurenine pathway in AD ‐  Connection of oxidative stress and kynurenines ‐  Glutamatergic excitotoxicity ‐  Inflammation •  A future therapeutic approach: modulating the kynurenine pathway •  Concluding remarks

Altered tryptophan metabolism in Parkinson's disease: A possible novel therapeutic approach

Parkinsons disease (PD) is one of the most common disabling neurodegenerative diseases. Although several therapeutic approaches are available, there are two major unresolved issues: the lack of proved neuroprotective therapy and the treatment of L-dopa-induced motor complications. In the brain, 90% of the tryptophan is metabolized in the kynurenine pathway. Some of the intermediates, such as quinolinic acid and 3-hydroxy kynurenine, are neurotoxic, while others, such as kynurenic acid, are putative intrinsic neuroprotective compounds, mainly by acting as endogenous antagonists of ionotropic excitatory amino acid receptors. Alterations in the kynurenine pathway have been demonstrated in PD. Preclinical data suggest that intervention in the kynurenine pathway may result in neuroprotection and may alleviate L-dopa-induced dyskinesia. There are two alternative approaches for such intervention: the use of kynurenic acid analogues or pro-drugs, or modulation of the activities of the intrinsic enzymes of the pathway.

Pharmacological therapy in Parkinson's disease: focus on neuroprotection.

Although the number of available therapeutic approaches in Parkinsons disease (PD) is steadily increasing the search for effective neuroprotective agent is continuing. Such research is directed at influencing the key steps in the pathomechanism: the mitochondrial dysfunction, the oxidative stress, the neuroinflammatory processes and the final common apoptotic pathway. Earlier‐developed symptomatic therapies were implicated to be neuroprotective, and promising novel disease modifying approaches were brought into the focus of interest. The current review presents a survey of our current knowledge relating to the pathomechanism of PD and discusses the putative neuroprotective therapy.

Release of PACAP-38 in episodic cluster headache patients - an exploratory study

BackgroundActivation of the trigeminal-autonomic reflex, involving the trigeminal ganglion, the superior salivatory nucleus and the sphenopalatine ganglion (SPG) is crucial in the pathophysiology of cluster headache (CH). Since pituitary adenylate cyclase-activating polypeptide-38 (PACAP-38) is present both in the SPG and the trigeminal ganglion (TG) and its role in migraine has been described, our aim was to determine the plasma PACAP-38 levels in different phases of episodic CH (ECH).Peripheral cubital fossa blood samples were taken during the ictal and inter-bout periods of male ECH patients and from age-matched healthy controls (n = 9). Plasma PACAP-38-like immunoreactivity (LI) was measured with specific and sensitive radioimmunoassay.FindingsSignificantly lower plasma PACAP-38-LI was detected in the inter-bout period of ECH patients than in healthy controls. However, PACAP-38 was significantly elevated in the plasma during CH attacks as compared to the inter-bout phase in the same subjects (n = 5).ConclusionsThis exploratory study suggests that PACAP-38 may be released during the attacks of ECH. Further patients and long-term follow-up are necessary to reveal its function.

Cortical and subcortical atrophy in alzheimer disease: Parallel atrophy of thalamus and hippocampus

Brain atrophy is a key imaging hallmark of Alzheimer disease (AD). In this study, we carried out an integrative evaluation of AD-related atrophy. Twelve patients with AD and 13 healthy controls were enrolled. We conducted a cross-sectional analysis of total brain tissue volumes with SIENAX. Localized gray matter atrophy was identified with optimized voxel-wise morphometry (FSL-VBM), and subcortical atrophy was evaluated by active shape model implemented in FMRIB’s Integrated Registration Segmentation Toolkit. SIENAX analysis demonstrated total brain atrophy in AD patients; voxel-based morphometry analysis showed atrophy in the bilateral mediotemporal regions and in the posterior brain regions. In addition, regarding the diminished volumes of thalami and hippocampi in AD patients, subsequent vertex analysis of the segmented structures indicated shrinkage of the bilateral anterior thalami and the left medial hippocampus. Interestingly, the volume of the thalami and hippocampi were highly correlated with the volume of the thalami and amygdalae on both sides in AD patients, but not in healthy controls. This complex structural information proved useful in the detailed interpretation of AD-related neurodegenerative process, as the multilevel approach showed both global and local atrophy on cortical and subcortical levels. Most importantly, our results raise the possibility that subcortical structure atrophy is not independent in AD patients.

Novel therapy in Parkinson's disease: adenosine A2A receptor antagonists

Introduction: Parkinsons disease (PD) is a progressive neurodegenerative disorder. To date, most of the currently available therapies in PD target the dopaminergic system and none of these therapeutic approaches have been proven to modify the course of the disease. To various extents, these drugs can also cause motor and non-motor complications. A novel target, the adenosine A2A receptor (AA2AR), was recently identified, blockade of which may alleviate Parkinsonian symptoms, reduce motor fluctuations and potentially afford neuroprotection. Areas covered: This review is based on a PubMed search covering the relationship of the adenosine receptors and PD. The role of the AA2AR is reviewed and the results of preclinical investigations of antagonists are assessed. A synopsis of current drug development is provided, with a special focus on the pharmacokinetics and relevant clinical trials. Expert opinion: The localization of the AA2AR in the central nervous system, the ultra structural localization and the molecular mechanism of its action reveal the potential importance of the AA2AR in movement disorders. The theoretical background and experimental data indicate that AA2AR antagonists may have a potential therapeutic effect in Parkinsons disease. More importantly, the putative neuroprotective effect needs further investigation.

Target identification for stereotactic thalamotomy using diffusion tractography.

Background Stereotactic targets for thalamotomy are usually derived from population-based coordinates. Individual anatomy is used only to scale the coordinates based on the location of some internal guide points. While on conventional MR imaging the thalamic nuclei are indistinguishable, recently it has become possible to identify individual thalamic nuclei using different connectivity profiles, as defined by MR diffusion tractography. Methodology and Principal Findings Here we investigated the inter-individual variation of the location of target nuclei for thalamotomy: the putative ventralis oralis posterior (Vop) and the ventral intermedius (Vim) nucleus as defined by probabilistic tractography. We showed that the mean inter-individual distance of the peak Vop location is 7.33 mm and 7.42 mm for Vim. The mean overlap between individual Vop nuclei was 40.2% and it was 31.8% for Vim nuclei. As a proof of concept, we also present a patient who underwent Vop thalamotomy for untreatable tremor caused by traumatic brain injury and another patient who underwent Vim thalamotomy for essential tremor. The probabilistic tractography indicated that the successful tremor control was achieved with lesions in the Vop and Vim respectively. Conclusions Our data call attention to the need for a better appreciation of the individual anatomy when planning stereotactic functional neurosurgery.

White matter disintegration in cluster headache.

BackgroundPrevious studies in primary headache disorders showed microstructural alterations in the white matter as measured by diffusion imaging. However these investigations are not in full agreement and some of those, especially in cluster headache, restricted the analysis to only a limited number of diffusion parameters. Therefore, in the current study we examined white matter microstructure in cluster headache patients.MethodsDiffusion weighted MRI images with 60 directions were acquired from thirteen patients with cluster headache and sixteen age-matched healthy controls. Tract based spatial statistics were used to compare white matter integrity in the core of the fibre bundles. Correlation of the diffusion parameters with cumulative number of headache days was examined.ResultsThere was a significant increment of the mean, axial and perpendicular diffusivity in widespread white matter regions in the frontal, parietal, temporal and occipital lobes. Reduced fractional anisotropy was found in the corpus callosum and some frontal and parietal white matter tracts mainly in the contralateral side of the pain. Axial diffusivity showed negative correlation to the number of the headache attacks.ConclusionsThe in vivo analysis of microstructural alterations in cluster headache provides important features of the disease, which might offer a deeper insight into the pathomechanism of the disease.