Investigation of vitamin D receptor polymorphisms in amyotrophic lateral sclerosis.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) patients manifest aberrations in the vitamin D endocrine system, with a vitamin D deficiency. Genetic investigations have identified those proteins which link vitamin D to ALS pathology: major histocompatibility complex class II molecules, toll-like receptors, poly(ADP ribose) polymerase-1, haeme oxygenase-1, the reduced form of nicotinamide adenine dinucleotide phosphate and calcium-binding proteins. Vitamin D additionally impacts ALS through cell-signalling mechanisms: glutamate, matrix metalloproteinases, the Wnt/ß-catenin signalling pathway, mitogen-activated protein kinase pathways, prostaglandins, reactive oxygen species and nitric oxide synthase, but its role has been only poorly investigated. OBJECTIVE: Our aim was to investigate vitamin D receptor (VDR) gene single nucleotide polymorphisms (SNPs) in an ALS population. This gene encodes the nuclear hormone receptor for vitamin D3. MATERIALS AND METHODS: A total of 75 consecutive sporadic ALS patients (~20% of the Hungarian ALS population) and 97 healthy controls were enrolled to investigate the possible effects of the different VDR alleles. A restriction fragment length polymorphism technique was utilized for allele discrimination. RESULTS: One of the four investigated SNPs was associated with the disease, but none of the alleles of these SNPs influenced the age at disease onset. The ApaI A allele was more frequent in the ALS group than in the control group and may be an ALS risk factor. CONCLUSIONS: This is the first verification of the genetic link between ALS and VDR. However, further studies are needed to confirm these findings.

Synthesis and biological effects of some kynurenic acid analogs.

The overactivation of excitatory amino acid receptors plays a key role in the pathomechanism of several neurodegenerative disorders and in ischemic and post-ischemic events. Kynurenic acid (KYNA) is an endogenous product of the tryptophan metabolism and, as a broad-spectrum antagonist of excitatory amino acid receptors, may serve as a protective agent in neurological disorders. The use of KYNA is excluded, however, because it hardly crosses the blood-brain barrier. Accordingly, new KYNA analogs which can readily cross this barrier and exert their complex anti-excitatory activity are generally needed. During the past 6 years, we have developed several KYNA derivatives, among others KYNA amides. These new analogs included one, N-(2-N,N-dimethylaminoethyl)-4-oxo-1H-quinoline-2-carboxamide hydrochloride (KYNA-1), that has proved to be neuroprotective in several models. This paper reports on the synthesis of 10 new KYNA amides (KYNA-1-KYNA-10) and on the effectiveness of these molecules as inhibitors of excitatory synaptic transmission in the CA1 region of the hippocampus. The molecular structure and functional effects of KYNA-1 are compared with those of other KYNA amides. Behavioral studies with these KYNA amides demonstrated that they do not exert significant nonspecific general side-effects. KYNA-1 may therefore be considered a promising candidate for clinical studies.

Neuroprotective effects of creatine in a transgenic animal model of amyotrophic lateral sclerosis.

Mitochondria are particularly vulnerable to oxidative stress, and mitochondrial swelling and vacuolization are among the earliest pathologic features found in two strains of transgenic amyotrophic lateral sclerosis (ALS) mice with SOD1 mutations. Mice with the G93A human SOD1 mutation have altered electron transport enzymes, and expression of the mutant enzyme in vitro results in a loss of mitochondrial membrane potential and elevated cytosolic calcium concentration. Mitochondrial dysfunction may lead to ATP depletion, which may contribute to cell death. If this is true, then buffering intracellular energy levels could exert neuroprotective effects. Creatine kinase and its substrates creatine and phosphocreatine constitute an intricate cellular energy buffering and transport system connecting sites of energy production (mitochondria) with sites of energy consumption, and creatine administration stabilizes the mitochondrial creatine kinase and inhibits opening of the mitochondrial transition pore. We found that oral administration of creatine produced a dose-dependent improvement in motor performance and extended survival in G93A transgenic mice, and it protected mice from loss of both motor neurons and substantia nigra neurons at 120 days of age. Creatine administration protected G93A transgenic mice from increases in biochemical indices of oxidative damage. Therefore, creatine administration may be a new therapeutic strategy for ALS.

Kynurenines in chronic neurodegenerative disorders: future therapeutic strategies.

Parkinson's, Alzheimer's and Huntington's diseases are chronic neurodegenerative disorders of a progressive nature which lead to a considerable deterioration of the quality of life. Their pathomechanisms display some common features, including an imbalance of the tryptophan metabolism. Alterations in the concentrations of neuroactive kynurenines can be accompanied by devastating excitotoxic injuries and metabolic disturbances. From therapeutic considerations, possibilities that come into account include increasing the neuroprotective effect of kynurenic acid, or decreasing the levels of neurotoxic 3-hydroxy-L-kynurenine and quinolinic acid. The experimental data indicate that neuroprotection can be achieved by both alternatives, suggesting opportunities for further drug development in this field.

Histopathological comparison of Kearns-Sayre syndrome and PGC-1α-deficient mice suggests a novel concept for vacuole formation in mitochondrial encephalopathy.

Despite the current hypotheses about myelinic and astrocytic ion-dyshomeostasis underlying white (WM) and grey matter (GM) vacuolation in mitochondrial encephalopathies, there is a paucity of data on the exact mechanism of vacuole formation. To revisit the concepts of vacuole formation associated with mitochondrial dysfunction, we performed a comparative neuropathological analysis in Kearns-Sayre syndrome (KSS) and full-length peroxisome proliferator-activated receptor-g coactivator-1a (FL-PGC-1a)-deficient mice, a recently proposed morphological model of mitochondrial encephalopathies. Brain tissues from an individual with genetically proven KSS (22-year-old man) and aged FL-PGC-1a-deficient and wild-type (male, 70-75-week-old) mice were analysed using ultrastructural and immunohistochemical methods, with a specific focus on myelin-related, oligodendroglial, axonal and astrocytic pathologies. Besides demonstrating remarkable similarities in the lesion profile of KSS and FL-PGC-1a-deficient mice, this study first provides morphological evidence for the identical origin of WM and GM vacuolation as well as for the presence of intracytoplasmic oligodendroglial vacuoles in mitochondriopathies. Based on these observations, the paper proposes a theoretical model for the development of focal myelin vacuolation as opposed to the original concepts of intramyelin oedema. Placing oligodendrocytes in the centre of tissue lesioning in conditions related to defects in mitochondria, our observations support the rationale for cytoprotective targeting of oligodendrocytes in mitochondrial encephalopathies, and may also have implications in brain aging and multiple sclerosis, as discussed.

Mice deficient in cellular glutathione peroxidase show increased vulnerability to malonate, 3-nitropropionic acid, and 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine.

Glutathione peroxidase (GSHPx) is a critical intracellular enzyme involved in detoxification of hydrogen peroxide (H(2)O(2)) to water. In the present study we examined the susceptibility of mice with a disruption of the glutathione peroxidase gene to the neurotoxic effects of malonate, 3-nitropropionic acid (3-NP), and 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP). Glutathione peroxidase knock-out mice showed no evidence of neuropathological or behavioral abnormalities at 2-3 months of age. Intrastriatal injections of malonate resulted in a significant twofold increase in lesion volume in homozygote GSHPx knock-out mice as compared to both heterozygote GSHPx knock-out and wild-type control mice. Malonate-induced increases in conversion of salicylate to 2,3- and 2, 5-dihydroxybenzoic acid, an index of hydroxyl radical generation, were greater in homozygote GSHPx knock-out mice as compared with both heterozygote GSHPx knock-out and wild-type control mice. Administration of MPTP resulted in significantly greater depletions of dopamine, 3,4-dihydroxybenzoic acid, and homovanillic acid in GSHPx knock-out mice than those seen in wild-type control mice. Striatal 3-nitrotyrosine (3-NT) concentrations after MPTP were significantly increased in GSHPx knock-out mice as compared with wild-type control mice. Systemic 3-NP administration resulted in significantly greater striatal damage and increases in 3-NT in GSHPx knock-out mice as compared to wild-type control mice. The present results indicate that a knock-out of GSHPx may be adequately compensated under nonstressed conditions, but that after administration of mitochondrial toxins GSHPx plays an important role in detoxifying increases in oxygen radicals.

Inhibition of neuronal nitric oxide synthase protects against MPTP toxicity.

Previous work showed that several relatively specific inhibitors of neuronal nitric oxide synthase (nNOS) produce protection against MPTP induced dopaminergic toxicity. We examined whether a highly specific novel inhibitor of nNOS, ARRI 7338, could also protect against MPTP toxicity. ARR17338 produced dose-dependent significant protection against MPTP induced depletion of dopamine and protected against MPTP induced depletions of tyrosine hydroxylase immunostained neurons in the substantia nigra. These results provide further evidence that inhibitors of nNOS may be useful for the treatment of Parkinson's disease.

N-acetyl-L-cysteine improves survival and preserves motor performance in an animal model of familial amyotrophic lateral sclerosis.

Increasing evidence implicates oxidative damage as a major mechanism in the pathogenesis of amyotrophic lateral sclerosis (ALS). We examined the effect of preventative treatment with N-acetyl-L-cysteine (NAC), an agent that reduces free radical damage, in transgenic mice with a superoxide dismutase (SODI) mutation (G93A), used as an animal model of familial ALS. NAC was administered at 1% concentration in the drinking water from 4-5 weeks of age. The treatment caused a significantly prolonged survival and delayed onset of motor impairment in G93A mice treated with NAC compared to control mice. These results provide further evidence for the involvement of free radical damage in the G93A mice, and support the possibility that NAC, an over-the-counter antioxidant, could be explored in clinical trials for ALS.

Nonenzymatic antioxidants of blood in multiple sclerosis.

Free radical action has been suggested as a causal factor in multiple sclerosis. We investigated the plasma level of lipid peroxides expressed in terms of malone dialdehyde and changes in blood nonenzymatic antioxidants (glutathione, alpha-tocopherol, retinol, plasma sulfhydryl groups, and uric acid) in multiple sclerosis patients with exacerbation or in remission, including a group treated with beta-interferon. The malone dialdehyde level was increased by 38% (n.s.) during exacerbations. The blood concentration of oxidized glutathione was likewise elevated (P<0.05), while the ratio of plasma alpha-tocopherol to cholesterol plus triglyceride was decreased (P<0.001). These changes suggest increased free radical production and consumption of the scavenger molecules during the active phase of the disease. Blood reduced glutathione level was increased (P<0.01) during exacerbation and remission as well. The rise in this thiol is likely to be a compensatory mechanism defending the cells from further oxidant injuries. Beta-interferon increased plasma alpha-tocopherol levels (P<0.001) but not the lipid corrected alpha-tocopherol value. Other parameters were not influenced by the drug.

Somatostatin and Alzheimer's disease.

One of the most consistent neurochemical deficits in Alzheimer's disease is a reduction in cortical somatostatin concentrations. The probability of a predominant regulatory change is heightened by the finding that 90% of somatostatin positive nonpyramidal neurons are also positive for NADPH, and NADPH neurons are 'protected' in Alzheimer's disease and do not appear to be lost. The first evidence that somatostatin influences learning and memory processes in experimental animals was published more than a decade ago. These reports of somatostatin effects on cognitive functions in rats were later confirmed by several other studies. The somatostatin depleting substance cysteamine inhibited the learning and memory performance of rats in active and passive avoidance behavior tests. Post-mortem human studies suggest that although somatostatin concentration is reduced, the somatostatin receptors are less affected in the brain in Alzheimer's disease. These findings may be of importance for possible therapeutic approaches using somatostatin-receptor-influencing compounds.

[Clinical symptoms, diagnosis and treatment of focal dystonias]. / A fokális dystoniák tünettana, diagnosztikája és kezelése.

Focal dystonias are relatively rare and significantly disabling disorders. These include cervical dystonia, blepharospasm and hemifacial spasm. The spasmodic torticollis consists of tonic posturing of the head away from its neutral position or twisting of the cervical muscles. The blepharospasm is an abnormal blinking, eyelid tic or twitch resulting from any cause. The hemifacial spasm is an involuntary unilateral twitching of the facial muscle. Patients affected by focal dystonias are predominantly females, and many times psychical stress can be revealed. The pathogenesis may involve dysfunction of the basal ganglia and brain stem although the exact mechanism remains to be elucidated. The patients need to be diagnosed and treated in centers specialized in movement disorders. Although many drug treatments can be beneficial, the most effective treatment is the local Botulinum toxin injection into the affected muscles. This neurotoxin produces temporary neuromuscular blockade, which reveals the symptoms and pain. The effect of the toxin is temporary and, therefore, the injection needs to be repeated every 6-12 weeks. The most common side effects are hypersensitivity, bleeding, hematoma, ptosis, facial spasm, dysphasia or dysarthria. With the use of proper dose and injection sites these side effects can be avoided.

[Neurodegeneration: aging and dementia. Etiopathogenic role of electron transport disorders. Therapeutic possibilities]. / Neurodegeneráció: öregedés és demencia. Elektrontranszport-zavar, mint etiopatogenetikai tényezó. Terápiás lehetóségek.

The neurodegenerative disorders (Parkinson's disease, Alzheimer's dementia, Huntington's disease, cerebellar degeneration) are common medical and social problems. The late onset diseases and slow neurodegeneration is connected with excitotoxins and alteration of mitochondrial electron transport chain. In elderly, congenital and acquired defects of mitochondrial complexes cause formation of free radicals. The overstimulation of excitatory amino acid receptors interfere with the cellular energy metabolism and also forming reactive oxygen species. The impaired energy metabolism make neuronal cells vulnerable to the excitotoxic damage. In these ways, excitotoxicity may be the final common pathway of neuronal death in a variety of neurodegenerative diseases. Potential therapeutic strategies would be use receptor antagonist or drugs to bypass energetic defects.

[Results of surgical treatment in hemifacial spasm--the role of MR-angiography in detecting microvascular compression]. / Hemifacialis spasmus mútéti kezelésének eredménye MR-angiográfiával kimutatott microvascularis kompresszió esetén.

The authors evaluated the follow-up results of microvascular decompression (sec. Janetta) in 8 patients with hemifacial spasm (HFS). Indication was based on there dimensional time of flight magnetic resonance angiography with 0.5T Elscint Gyrex V Dix equipment. Contrast material was administered in every case and maximum intensity projection and thin slice reconstruction were performed in three standard directions. Vascular contact with the facial nerve in the entry zone was identified on the symptomatic side in 10 patients. No contact was detected in 2 cases. Microvascular decompression was performed in 8 cases. The surgical and neuroradiological findings were identical in every cases. Five patients were completely free of HFS immediately after surgery, and another 2 patients became free of HFS during the next few weeks. Only 1 patient had uncured symptoms. In conclusion, the authors suggest that microvascular decompression of the facial nerve may evolve as the method of choice if vascular contact is proved by 3D TOF MRA.

[Treatment of relapsing-remitting multiple sclerosis with interferon beta type 1-b]. / A relapszus-remisszió kórformájú sclerosis multiplexes betegek kezelése interferon-béta-1b-vel.

Interferon-beta-1b was the first drug found to slow the progression of relapsing-remitting multiple sclerosis, with a reported decrease in the relapse rate of up to 34%. The present study involved 35 patients treated with interferon-beta-1b for one year. The aims of the study were: a) to compare the changes in the relapse rate and the number of days of hospitalization with other data, b) to compare the steroid needs required to treat relapses for one year before and in the year of interferon-beta-1b treatment. Our data indicated that the relapse rate may decrease as much as 77% following the introduction of interferon-beta-1b treatment. The adverse effects and the changes in the EDSS grades were similar to the published data. The duration of hospitalization decreased by 84% and the amount of methylprednisolone needed for remission by 78%. This data suggest that the impairment of the condition of the patients may be delayed considerably, while some of them can continue to work for a longer period, the standard of life of these patients therefore being more tolerable.

Mitochondrial disturbances, tryptophan metabolites and neurodegeneration: medicinal chemistry aspects.

Neurodegenerative disorders, e.g. Parkinson's, Huntington's and Alzheimer's diseases are distinct clinical and pathological entities sharing a number of leading features in their underlying processes. These common features involve the disturbances in the normal functioning of the mitochondria and the alterations in the delicate balance of tryptophan metabolism. The development of agents capable of halting the progression of these diseases is in the limelight of neuroscience research. This review highlights the role of mitochondria in the development of neurodegenerative processes with special focus on the involvement of neuroactive kynurenines both as pathological agents and potential targets and tools for future therapeutic approaches by providing a comprehensive summary of the main streams of rational drug design and giving an insight into present clinical achievements.

Kynurenine metabolism in multiple sclerosis.

Objective--Excitatory amino acid receptors are involved in the normal physiology of the brain, and may play a role in the pathogenesis of neurological disorders such as Huntington's disease, Parkinson's disease, amyotrophic lateral sclerosis, etc. It has been demonstrated that the blockade of one of these receptors ameliorates the symptoms of experimental allergic encephalomyelitis, an animal model of multiple sclerosis (MS). In a recent study, a decreased level of kynurenic acid was found in the cerebrospinal fluid of patients with MS. The only known endogenous excitotoxin receptor antagonist is the tryptophan metabolite kynurenic acid. Another metabolite is quinolinic acid, which exerts different action: it is an excitotoxin receptor agonist. The ratio of these two metabolites is determined by the activities of kynurenine aminotransferase I and II (KAT I and KAT II). In this study, we measured the activities of these enzymes and the concentration of kynurenic acid in the red blood cells (RBC) and in the plasma of patients with MS. KAT activities were detected both in the RBC and in the plasma. As compared with the control subjects, the KAT I and KAT II activities were significantly higher in the RBC of the patients. The concentration of kynurenic acid is elevated in the plasma of MS patients, and there is a tendency to an elevation in the RBC. These changes may indicate a compensatory protective mechanism against excitatory neurotoxic effects. Our data demonstrate the involvement of the kynurenine system in the pathogenesis of MS, which may predict a novel therapeutic intervention.

Amino acid concentrations in cerebrospinal fluid of patients with multiple sclerosis.

As oligodendrocytes have binding sites for excitatory amino acids (glutamate, aspartate, serine, etc.), a role of these molecules in demyelinating disorders is possible. We measured the levels of amino acids in the cerebrospinal fluid (CSF) of patients with multiple sclerosis in comparison with CSF obtained by myelography from patients with lower back pain. There were no significant differences in the CSF concentrations of these amino acids between the two groups. Normal concentrations of excitotoxins do not exclude the role of these molecules in demyelinating disorders.

Amino acids in the saliva of patients with migraine.

There are a number of hypotheses concerning the pathogenesis of migraine, but they are frequently conflicting. In addition to the vascular hypothesis, clinical data are available that excitatory amino acids may play an important role in the development of the disease. In this study, free amino acid concentrations were measured by RP-HPLC in the saliva of 23 migraineurs without aura, 14 migraineurs with aura, and 20 healthy subjects. Significantly higher concentrations of glutamic acid, serine, glycine, arginine, and tyrosine were found in the saliva samples of both groups of migraineurs relative to the control group. It is suggested that amino acids causing hyperexcitability in the central nervous system may be linked to the pathogenesis of migraine.

Increased vulnerability to 3-nitropropionic acid in an animal model of Huntington's disease.

There is substantial evidence for both metabolic dysfunction and oxidative damage in Huntington's disease (HD). In the present study, we used in vivo microdialysis to measure the conversion of 4-hydroxybenzoic acid to 3,4-dihydroxybenzoic acid (3,4-DHBA) as a measure of hydroxyl radical production in a transgenic mouse model of HD, as well as in littermate controls. The conversion of 4-hydroxybenzoic acid to 3,4-DHBA was unchanged in the striatum of transgenic HD mice at baseline. Following administration of the mitochondrial toxin 3-nitropropionic acid (3-NP), there were significant increases in 3,4-DHBA generation in both control and transgenic HD mice, and the increases in the transgenic HD mice were significantly greater than those in controls. Furthermore, administration of 3-NP produced significantly larger striatal lesions in transgenic HD mice than in littermate controls. The present results show increased sensitivity to the mitochondrial toxin 3-NP in transgenic HD mice, which suggests metabolic dysfunction in this mouse model of HD.

The prevalence of multiple sclerosis, distribution of clinical forms of the disease and functional status of patients in Csongrád County, Hungary.

OBJECTIVE: The aim of this study was to determine the prevalence of multiple sclerosis (MS) in the population of Csongrád County, Hungary (400,128 inhabitants) and to determine the functional status (based on the Expanded Disability Status Scale; EDSS) of the patients according to the clinical forms of the disease. METHODS: The diagnosis was established with the aid of the Poser diagnostic criteria, and the degree of physical disability was determined using the Kurtzke EDSS. RESULTS: In Csongrád County, the prevalence of MS is 62/100,000. The distribution of patients according to the clinical forms of MS was as follows: 15% had the benign form, 54% had relapsing-remitting MS, 20% had secondary chronic progressive MS and 11% had the primary chronic progressive form of MS. Sixty percent of relapsing-remitting MS patients had an EDSS score of 0-4 points and 33% had an EDSS score of 4.5-6.5 points. CONCLUSION: The distribution of patients according to the clinical forms of the disease in this representative population is comparable to results in other regions of the world.