Clinical Neuroscience

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

SZARKA András

JULY 30, 2015

Clinical Neuroscience - 2015;68(07-08)

DOI: https://doi.org/10.18071/isz.68.0222

[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.]

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Clinical Neuroscience

[Radiosurgery of intracerebral cavernomas - Current international trends]

NAGY Gábor, KEMENY A. Andras, MAJOR Ottó, ERÕSS Loránd, VÁRADY Péter, MEZEY Géza, FEDORCSÁK Imre, BOGNÁR László

[Although still a controversial management option, radiosurgery of intracranial cavernomas has become increasingly popular world-wide during the last decade. Microsurgery is a safe and effective treatment for symptomatic hemispheric cavernomas. However, the indication for microsurgical resection of deep eloquent cavernomas is relatively limited even in experienced hands. The importance of radiosurgery has recently been appreciated in parallel with increasing positive experiences both in terms of effectiveness and safety, especially for cases high risk for surgical resection, in the brainstem, thalamus and basal ganglia. While radiosurgery was earlier indicated mainly for surgically inaccessible lesions that had bled multiple times, a more proactive policy has recently become more accepted. In our opinion preventive treatment with the low morbidity radiosurgery serves the patients’ interest especially for deep eloquent lesions that had bled not more than once, due to the cumulative morbidity of repeated hemorrhages. Despite our increasing knowledge on natural history, there is currently no available treatment algorithm for cavernomas. Arguments for all three treatment modalities (observation, microsurgery and radiosurgery) are established, but their indication criteria are yet to be defined. It is time to organize a prospective population based data collection in Hungary, which appears to be the most realistic way to clarify indication criteria.]

Clinical Neuroscience

[Radiosurgery of intracerebral cavernomas - Current Hungarian practice]

FEDORCSÁK Imre, NAGY Gábor, DOBAI József Gábor, MEZEY Géza, BOGNÁR László

[Background and purpose - Radiosurgery is an increasingly popular treatment option especially for deep eloquent intracerebral cavernomas that are often too risky for surgical removal, but their re-bleed carries significant risk for persisting neurological deficit. Gamma-radiation based radiosurgery has been being available since 2007 in Hungary in Debrecen. Our aim is to summarize our experience accumulated during the first five years of treatment and to compare it to the international experience. Patient selection and methods - We retrospectively analyzed 51 cavernomas in 45 patients treated between 2008 and 2012 in terms of localization, natural history, and the effect of radiosurgery on re-bleed risk and epilepsy, and its side effects. Results - We treated 26.5% deep eloquent (brainstem, thalamic/basal ganglia) and 72.5% superficial hemispheric cavernomas. The median presentation age was 25 years (13-60) for deep, and 45 years (6-67) for superficial cavernomas. They were treated median of 1 year after presentation. 64.5% of deep cavernomas bled before treatment, the annual risk of first hemorrhage was 2%/lesion, re-bleed risk 21.7%, with 44% persisting morbidity. 13.5% of superficial cavernomas bled prior to treatment, the risk of first bleed was 0.3%, there was no re-bleed, and 35% caused epilepsy. We used GammaART-6000TM rotating gamma system for treatment, marginal dose was 14 Gy (10-16), and treatment volume 1.38-1.53 cm3. Re-bleed risk of deep eloquent lesions fell to 4% during the first two years after treatment and to 0% thereafter, and no hemorrhage occurred from superficial lesions after treatment. Persisting morbidity in deep lesions came from adverse radiation effect in 7% and from re-bleed in 7%, and there was no persisting side effect in superficial cavernomas. 87.5% of cases of epilepsy resistant to medical therapy improved. Radiological regression was found in 37.5% and progression in 2% after treatment. Conclusions - Radiosurgery of cavernomas is safe and effective. Early preventive treatment for deep cavernomas carrying high surgical risk is justified. Moreover, for superficial lesions that are surgically easily accessible radiosurgery also appears to be an attractive alternative.]

Clinical Neuroscience

[Neurointerventional treatment of acute ischemic stroke: the Kaposvár experience]

RADNAI Péter, SZŐTS Mónika, RÁDAI Ferenc, HORVÁTH Gyula, VARGA Csaba, FOGAS János, SZÖRÉNYI Péter, HORVÁTH Zoltán, BAJZIK Gábor, MOIZS Mariann, REPA Imre, NAGY Ferenc, VAJDA Zsolt

[Aim of the study - In the present study, we report procedural and mid-term functional outcome data on the first 50 neurointerventional treatments of acute ischemic stroke in the Kaposi Mór County Hospital, Kaposvár, Hungary. Materials and methods - Endovascular recanalization of occluded large cervical and intracranial arteries was performed following an unsuccessful intravenous lysis or when intravenous lysis was contraindicated. A control cohort was retrospectively formed by analyzing data of 16 patients who has been unsuccesfully treated with iv. lysis before neurointervention was available in our hospital. Results and conclusion - Recanalization rate was 84% and major complication rate was 2% in the neurointerventional group. Mid-term good functional outcome, defined as mRS 0-2, was achieved in 44% in the neurointerventional and in 13% in the intravenous lysis group, after 11.5 and 39.7 months follow-up period, respectively. Subgroup analysis revealed patient age as the strongest predictive factor of good functional outcome. Our data shows that neurointerventional treatment of acute ischemic stroke gives substantially improved functional outcome, in accordance with the results of the recently published international randomized trials.]

Clinical Neuroscience

Mental health of physicians - nationwide representative study from Hungary

GYŐRFFY Zsuzsa, GIRASEK Edmond

Background and aim - Somatic and mental health and stress factors of physicians became an issue of growing interest in both national and international researches. Our aim is to give an overviewing analysis of Hungarian physicians’ mental health state. Methods - Representative, cross-sectional, quantitative survey on a representative sample of Hungarian physicians (n=4784). The control group was formed by the population group of a national survey conducted by “Hungarostudy 2013” (n=2000). Results - Suicidal thoughts (18.8% vs. 9.6%, p<0.001), the scores of Somatic Symptom Scale (PHQ-10, 20.4% vs. 13.6%, p<0.001) were significantly higher among physicians. The suicidal attempts (1.9% vs. 3.5%, p=0.053) and BDI depression scores (7.9% vs. 29.5%, p<0.001) were significantly higher in the control group. High Perceived Stress Scale (PPS) scores occurred in 43.3% of the physicians sample, and 43.4% of them had high scores in the Athenian Insomnia Scale (AIS). The young (<35) female physicians showed significantly higher rates of suicidal thoughts, higher scores of PHQ and PPS. In the young female cohort, the AIS scores were significantly higher than of the other physicians. Conclusions - Mental health of physicians (sleep disorders, suicidal thoughts and psychosomatic symptoms) showed poorer results than the population data. BDI scores and the rate of suicidal attempts showed favourable trends. The next step in the physicians’ mental health researches is to investigate the most decisive risk factors, and to work out the prevention tools.

Clinical Neuroscience

Thrombocytopenia with gabapentin usage

ATAKLI Dilek, YUKSEL Burcu, AK Dogan Pelin, SARIAHMETOGLU Hande, SARI Hüseyin

Gabapentin is an antiepileptic drug approved for adjunctive therapy for partial seizures. We report a case of a patient who had thrombocytopenia with the dose of 2400 mg/day of gabapentin. The causal relationship between gabapentin and thrombocytopenia was revealed by dramatic increase in thrombocyte count following the cessation of the gabapentin treatment. To our knowledge, this is the first case report with a hematopoietic side effect of gabapentin.

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

KOVÁCS Tibor

[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 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.]

Clinical Neuroscience

[Early mental test - developing a screening test for mild cognitive impairment]

KÁLMÁN János, PÁKÁSKI Magdolna, HOFFMANN Ildikó, DRÓTOS Gergely, DARVAS Gyöngyi, BODA Krisztina, BENCSIK Tamás, GYIMESI Alíz, GULYÁS Zsófia, BÁLINT Magdolna, SZATLÓCZKI Gréta, PAPP Edina

[Background and purpose - Mild cognitive impairment (MCI) is a heterogenous syndrome considered as a prodromal state of dementia with clinical importance in the early detection of Alzheimer’s Disease. We are currently developing an MCI screening instrument, the Early Mental Test (EMT) suitable to the needs of primary care physicians. The present study describes the validation process of the 6.2 version of the test. Methods - Only subjects (n=132, female 95, male 37) over the age of 55 (mean age 69.2 years (SD=6.59)) scoring at least 20 points on Mini-Mental State Examination (MMSE), mean education 11.17 years (SD=3.86) were included in the study. The psychometric evaluation consisted of Alzheimer’s Disease Assessment Scale Cognitive subscale (ADAS-Cog) and the 6.2 version of EMT. The statistical analyses were carried out using the 17.00 version of SPSS statistical package. Results - The optimalised cut-off point was found to be 3.45 points with corresponding 69% sensitivity, 69% specificity and 69% accuracy measures. The Cronbach-α, that describes the internal consistence of the test was 0.667, which is higher as compared with the same category in the case of the ADASCog (0.446). A weak negative rank correlation was found between the total score of EMT 6.2 and the age of probands (rs=-0.25, p=0.003). Similarly, only a weak correlation was found between the education levels and the total score of EMT 6.2 (rs=0.31, p<0.001). Two of the subtests, the repeated delayed short-time memory and the letter fluency test with a motorical distraction task had significantly better power to separate MCI and control groups than the other subtests of the EMT. Conclusion - The 6.2 version of EMT is a fast and simple detector of MCI with a similar sensitivity-specificity profile to the MMSE, but this version of the test definitely needs further development.]