Clinical Neuroscience

[ASSOCIATION OF APOLIPOPROTEIN E POLYMORPHISM WITH AGE-RELATED MACULAR DEGENERATION AND ALZHEIMER’S DISEASE IN SOUTH-WESTERN HUNGARY]

KOVÁCS Á. Katalin1, PÁMER Zsuzsanna1, KOVÁCS Attila2, FEKETE Sándor2, MISETA Attila3, KOVÁCS Bálint1, KOVÁCS L. Gábor3

MARCH 20, 2007

Clinical Neuroscience - 2007;60(03-04)

[Background - Age-related macular degeneration (AMD) and Alzheimer dementia (AD) show similarities (advanced age, formation of deposits of similar content). Recently apolipoprotein E 2 (apoE 2) has been associated with AMD, while apoE4 with AD. The question of coexistence, especially with respect to the genetic background has not been studied earlier. We investigated, therefore, the occurrence of AMD in AD patients and compared their lipid profile and apoE polymorphism. Methods - 49 AMD, 32 AD and 27 control patients were examined (risk factors, visual acuity, slit lamp biomicroscopy, fundoscopy). Following measurement of triglyceride, total and HDL cholesterol levels, apoE mutation analysis was performed. Results - AMD was found in 8% of the cooperating AD patients. The prevalence of the apoE 4 isoforms in the AMD, AD and the control patients was 2%, 47% and 22%, while that of apoE 2 was 17%, 6% and 7%, respectively. The prevalence of apoE 3 isoform was 82%, 41% and 71%, respectively. Triglyceride, total and HDL cholesterol were in the reference range; however, AD patients were characterized by a lower total cholesterol value. Conclusions - The new finding of this publication is the rare occurrence of AMD among AD patients. The higher frequency of apoE 4 among the AD population, and the higher frequency of apoE 2 among AMD patients in the South-Western region of Hungary confirms the findings of other investigators.]

AFFILIATIONS

  1. Department of Ophthalmology, University of Pécs, Pécs
  2. Department of Psychiatry and Psychotherapy, University of Pécs, Pécs
  3. Department of Laboratory Medicine, University of Pécs, Pécs

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Clinical Neuroscience

[PROTECTIVE ACTION OF SNAKE VENOM NAJA NAJA OXIANA AT SPINAL CORD HEMISECTION]

ABRAHAMYAN S. Silva, MELIKSETYAN B. Irina, CHAVUSHYAN A. Vergine, ALOYAN L. Mery, SARKISSIAN S. John

[Based on data accumulated regarding the neuroprotective action of Proline-Rich-Peptide-1 (PRP-1, a fragment of neurophysin vasopressin associated hypothalamic glycoprotein consisting of 15 amino acid residues) on neurons survival and axons regeneration and taking into the account that LVV-Hemorphin-7 (LVV-H7, an opioid peptide, widely distributed in different cell types of various tissues of intact rats, including those of the nervous and immune systems) derived from the proteolitic processing of hemoglobin in response to adverse environmental and physiological conditions, possesses the anti-stressor properties, we used histochemistry, immunohistochemistry and electrophysiology to investigate the putative neuroprotective action of Central Asian Cobra Naja naja oxiana snake venom (NOX) on trauma-injured rats. ABC immunohistochemical method and histochemical method on detection of Ca2+- dependent acid phosphatase activity were used for the morpho-functional study. By recording the electrical activity of the signals from the single neurons in and below the SC injury place, NOX venom has been shown to result in the complete restoration of hypothalamic-spinal projections originated from ipsi- and contra-lateral PVN and SON to neurons of SC lumbar part. NOX prevented the scar formation, well observed two months after SC injury in the control rats, resulted in the regeneration of nerve fibers growing through the trauma region, survival of the PRP-1- and LVV-H7-immunoreactive (Ir) neurons, and increase of the PRP-1- and LVV-H7-Ir nerve fibers and astrocytes in the SC lesion region. NOX was suggested to exert the neuroprotective effect, involving the PRP-1 and LVV-H7 in the underlying mechanism of neuronal recovery.]

Clinical Neuroscience

[CENTRAL ATRIAL NATRIURETIC PEPTIDE IN DEHYDRATION]

BAHNER Udo, GEIGER Helmut, PALKOVITS Miklós, LENKEI Zsolt, LUFT C. Friedrich, HEIDLAND August

[To test the effect of dehydration on brain atrial natriuretic peptide (ANP) concentrations in areas important to salt appetite, water balance and cardiovascular regulation, we subjected rats to dehydration and rehydration and measured ANP concentration in 18 brain areas, as well as all relevant peripheral parameters. Water deprivation decreased body weight, blood pressure, urine volume, and plasma ANP, while it increased urine and plasma osmolality, angiotensin II, and vasopressin. ANP greatly increased in 17 and 18 brain areas (all cut cerebral cortex) by 24 h. Rehydration for 12 h corrected all changes evoked by dehydration, including elevated ANP levels in brain. We conclude that chronic dehydration results in increased ANP in brain areas important to salt appetite and water balance. These results support a role for ANP as a neuroregulatory substance that participates in salt and water balance.]

Clinical Neuroscience

[OXYGEN-GLUCOSE DEPRIVATION-INDUCED CHANGES IN ORGANOTYPIC CULTURES OF THE RAT HIPPOCAMPUS]

BALI Balázs, NAGY Zoltán, KOVÁCS J. Krisztina

[Introduction - (-)Deprenyl is an irreversible inhibitor of type B monoamine oxidase (MAO-B), which is now used for treatment of Parkinson’s or Alzheimer’s diseases. Evidence suggests that the neuroprotective effect of deprenyl may not be related exclusively to the inhibition of the enzyme MAO-B. Methods - To test the impact of deprenyl on ischemiainduced changes in vitro, we followed the time course of propidium iodide (PI) uptake as an indicator of neuronal cell death as well as the expression of apoptotic factors in organotypic hippocampal slice cultures exposed to oxygen- glucose deprivation (OGD) for 45 min. Results - The first signs of neuronal death were detected 2 hours after OGD and were extended to all subfields of the hippocampus by 24 hours post-injury. Presence of deprenyl (10-9 M) significantly delayed the cell death induced by the insult. Exposure of control cultures to deprenyl significantly increased the abundance of Bcl-2 and Bcl-xl mRNAs as revealed by RT-PCR. OGD resulted in an elevation of anti-apoptotic factors, while the expression of pro-apoptotic bax remained unchanged. Conclusion - These data suggest that deprenyl is neuroprotective in an in vitro model of ischemia. Although deprenyl upregulates the expression of Bcl-2 under basal conditions, its effect on anti-apoptotic factors is not significantly manifested during OGD.]

Clinical Neuroscience

[EFFECT OF LOCAL (INTRACEREBRAL AND INTRACEREBROVENTRICULAR) ADMINISTRATION OF TYROSINE HYDROXYLASE INHIBITOR ON THE NEUROENDOCRINE DOPAMINERGIC NEURONS AND PROLACTIN RELEASE]

BODNÁR Ibolya, HECHTL Dániel, SZÉKÁCS Dániel, OLÁH Márk, NAGY M. György

[Background and purpose - Hypothalamic dopamine (DA), the physiological regulator of pituitary prolactin (PRL) secretion, is synthesized in the neuroendocrine DAergic neurons that projects to the median eminence and the neurointermediate lobe of the pituitary gland. The rate-limiting step of DA biosynthesis is catalyzed by the phosphorylated, therefore activated, tyrosine hydroxylase (TH) that produces L-3,4-dihydroxy- phenylalanine from tyrosine. The aims of our present study were to investigate 1. the effect of local inhibition of the DA biosynthesis in the hypothalamic arcuate nucleus on PRL release, and to get 2. some information whether the phosphorylated TH is the target of enzyme inhibition or not. Methods - A TH inhibitor, α-methyl-p-tyrosine was injected either intracerebro-ventricularly or into the arcuate nucleus of freely moving rats and plasma PRL concentration was measured. Immunohistochemistry, using antibodies raised against to native as well as phosphorylated TH were used to compare their distributions in the arcuate nucleus-median eminence region. Results - Intracerebro-ventricular administration of α-methyl-p-tyrosine has no effect, unlike the intra-arcuatus injection of enzyme inhibitor resulted in a slight but significant elevation in plasma PRL. Parallel with this, the level of DA and DOPAC were reduced in the neurointermediate lobe while no change in norepinephrine concentration can be detected indicating a reduced biosynthesis of dopamine following TH inhibition. On the other hand, systematic application of the α-methyl-p-tyrosine that inhibits TH activity located in DA terminals of the median eminence and the neurointermediate lobe, resulted in the most significant elevation of PRL. Conclusion - Our results suggest that α-methyl-p-tyrosine administered close to the neuroendocrine DAergic neurons was able to inhibit only a small proportion of the TH. Moreover, it also indicate that the majority of the activated TH can be found in the axon terminals of DAergic neurons, therefore, the DA released into the pituitary portal circulation is synthesized at this site.]

Clinical Neuroscience

[USING BRAIN SLICE CULTURES OF MOUSE BRAIN TO ASSESS THE EFFECT OF GROWTH FACTORS ON DIFFERENTIATION OF BONE MARROW DERIVED STEM CELLS]

BRATINCSÁK András, LONYAI Anna, SHAHAR Tal, HANSEN Arne, TÓTH E. Zsuzsanna, MEZEY Éva

[Bone marrow derived stem cells (BMDSCs) have been reported to form neurons and supportive cells in the brain. We describe a technique that combines the simplicity of in vitro studies with many of the advantages of in vivo experiments. We cultured mouse brain slices, deposited GFPtagged BMDSCs evenly distributed on their surfaces, and then added test factors to the culture medium. Addition of both SDF-1 and EGF resulted in morphological changes of BMDSC and in the induction of islet-1, a marker of neuroepithelial progenitors. We conclude that organotypic tissue culture (OTC) may allow us to detect the effects of exogenous factors on the differentiation of BMDSCs (or any other type of stem cells) in an environment that may resemble the CNS after brain injury. Once such factors have been identified they could be evaluated for tissue regeneration in more complex, whole animal models.]

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[The effects of angiotensin receptor blockers on the nervous system in hypertension and dementia]

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[The renin-angiotensin system (RAS) is one of the most important mechanisms regarding the pathomechanism and treatment of hyprtension. The most of the elements of the RAS are found in the nervous system too. The effect of angiotensin converting enzyme inhibitors and angiotensin receptor blockers (ARBs) is based on the inhibition of the RAS. ARBs might have a special role in the central nervous system because they do not decrease the production of angiotensin but inhibit its harmful effects mediated through the AT1 receptor while allowing the stimulation of AT2 receptors with resulting pleiotrophic actions. Hypertension is the most important risk factor for stroke and has a negative effect on cognitive functions. Antihypertensive treatment has an effect on the nervous system; in addition to the consequences of the reduced blood pressure, ARBs might provide additional advantages in stroke and dementia prevention.]

Clinical Neuroscience

[The role of β-amyloid and mitochondrial dysfunction in the pathogenesis of Alzheimer’s disease]

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[Alzheimer’s disease is the most common form of dementia in mid- and late life. The 7-10% of the population over 65 and the 50-60% of the population over 85 are affected by this disease. On the contrary of its prevalence the pathogenesis of the disease is not well defined and there is no effective neuroprotective therapeutic agent. Three predominant neuropathological features of the Alzheimer’s disease brain are intracellular neurofibrillary tangles consisting mainly of the hyperphosphorylated protein t; the extracellular amyloid deposits (neuritic plaques) consisting of amyloid b peptide; and the extensive neuronal cell loss in the hippocampus and in portions of the cerebral cortex. The possible reason of the extensive neuronal cell loss can be the mitochondrial dysfunction observed in Alzheimer’s disease. Beyond the unclarified pathogenesis the causality of these characteristic neuropathologic phenomena are still unknown. In this study we would like to deal with two actual hypotheses, with the amyloid cascade and with the mitochondrial cascade hypotheses. We try to give an overview of these two hypotheses and to depict their interrelationship.]

Clinical Neuroscience

[The effect of angiotensin receptor blockers in cerebrovascular disorders and dementia: Bonus in addition to the antihypertensive effect]

KOVÁCS Tibor

[Hypertension and dementia are frequent disorders or rather syndromes. Their incidence is growing with advancing age and hypertension is increasing the risk of cognitive impairment too, while treating hypertension (i.e. the use of antihypertensive medications) is decreasing it. In addition, hypertension is the most important risk factor for stroke. The renin-angiotensin system (RAS) has a special role in the development of hypertension and also involved in the pathogenesis of the most frequent dementia form, namely Alzheimer’s disease. The effect of angiotensin convertase inhibitors and angiotensin receptor blockers (ARB) is based on the inhibition of the RAS, but the ARBs do not inhibit angiotensin formation, just blocking its harmful effects on the AT1 receptor, while allowing the activation of AT2 receptors with pleiotropic effects. Preclinical, epidemiological and clinical therapeutic studies suggest this additional effect of ARBs and these are summarized in this review.]

Clinical Neuroscience

[The role of immobilization stress and sertindole on the expression of APP, MAPK-1 and β-actin genes in rat brain]

KÁLMÁN János, PÁKÁSKI Magdolna, SZŰCS Szabina, KÁLMÁN Sára, FAZEKAS Örsike, SÁNTHA Petra, SZABÓ Gyula, JANKA Zoltán

[Stress, depending on its level and quality, may cause adaptive and maladaptive alterations in brain functioning. As one of its multiple effects, elevated blood cortisol levels decrease the synthesis of the neuroprotective BDNF, thus leading to hippocampal atrophy and synapse loss, and rendering it a possible cause for the Alzheimer’s disease (AD) related neuropathological and cognitive changes. As a result of the stress response, intraneuronal alterations - also affecting the metabolism of β-actin - can develop. These have a role in the regulation of memory formation (LTP), but in pathological conditions (AD) they could lead to the accumulation of Hirano bodies (actin-cofilin rods). According to the dementia treatment guidelines, the behavioural and psychological symptoms of AD can be treated with certain antipsychotics. Therefore, the aim of our study was to examine the effects of sertindole (currently not used in the standard management of AD) on the transcription of some AD associated genes (amyloid precursor protein [APP], mitogen activated protein kinase-1 [MAPK-1], β-actin) in the brain of rats exposed to chronic immobilization stress (CIS). Male Wistar rats were exposed to CIS for three weeks. The four groups were: control (n=16), CIS (n=10), 10 mg/kg sertindole (n=5) and 10 mg/kg sertindole + CIS (n=4). Following transcardial perfusion, the relative levels of hippocampal and cortical mRNA of the previously mentioned genes were measured with real-time PCR. CIS induced hippocampal β-actin (p<0.01), MAPK-1 and APP (p<0.05) mRNA overexpression. The simultaneous administration of sertindole suppressed this increase in β-actin, MAPK-1 and APP expression (p<0.05). Ours is the first report about CIS induced β-actin gene overexpression. This finding, in accordance with the similar results in APP and MAPK-1 expression, underlines the significance of cytoskeletal alterations in AD pathogenesis. The gene expression reducing effect of sertindole suggests that antipsychotic drugs may have a neuroprotective effect.]

Clinical Neuroscience

[Epidemiology of dementia in Hungary]

ÉRSEK Katalin, KÁRPÁTI Krisztián, KOVÁCS Tibor, CSILLIK Gabriella, GULÁCSI L. Ádám, GULÁCSI László

[Objective - To estimate the epidemiology and the distribution of disease severity of dementia in Hungary, using published data. To estimate the demented population of 2008 and to make a projection for 2050. Methodology - With an outlook for the international professional literature and the available Hungarian information we examine the epidemiology of dementia in Hungary by age-groups and disease severity (according to MMSE categories), then make our estimation for the entire population. Results - Based on the estimation of the number of demented people in Hungary there is a noticeable difference between the domestic and the internationally published data. According to previous Hungarian studies, the number of the demented subjects vary between 530 and 917 thousand patients. Multiplying the elderly age-group’s populations by the global prevalence data it results in 101 thousand of demented patients. Estimation by the domestic published data we remarkably overestimate the presumed value, whereas by using the global prevalence figures we underestimate. Conclusions - There is a strong need for a representative study to obtain exact figures on the prevalence of dementia in Hungary. Getting exact figures of the Hungarian prevalence of dementia it is a strong need an overall representative study. With the lack of it the health and social care systems are not able to prepare for providing the increasing number of patients.]