Diagnosis and biomarkers of predementia in Alzheimer's disease

In view of the growing prevalence of Alzheimer's disease (AD) worldwide, there is an urgent need for the development of better diagnostic tools and more effective therapeutic interventions. At the earliest stages of AD, no significant cognitive or functional impairment is detected by conventional clinical methods. However, new technologies based on structural and functional neuroimaging, and on the biochemical analysis of cerebrospinal fluid (CSF) may reveal correlates of intracerebral pathology in individuals with mild, predementia symptoms. These putative correlates are commonly referred to as AD-related biomarkers. The relevance of the early diagnosis of AD relies on the hypothesis that pharmacological interventions with disease-modifying compounds are likely to produce clinically relevant benefits if started early enough in the continuum towards dementia. Here we review the clinical characteristics of the prodromal and transitional states from normal cognitive ageing to dementia in AD. We further address recent developments in biomarker research to support the early diagnosis and prediction of dementia, and point out the challenges and perspectives for the translation of research data into clinical practice.

Interven����es psicoeducacionais para cuidadores de idosos com dem��ncia: uma revis��o sistem��tica

OBJETIVO: Identificar modelos de interven����es psicoeducacionais e os seus efeitos em cuidadores de idosos com dem��ncia. M��TODOS: Levantamento de estudos publicados entre janeiro de 2000 e abril de 2012 nas bases de dados PubMed, Web of Knowledge, Lilacs e SciELO, utilizando as seguintes palavras-chave "psychoeducational and caregiver", "cuidador e dem��ncia e psicoeduca����o" e "cuidador e interven����o". Apenas os artigos que denominavam a interven����o estudada como psicoeduca����o fazem parte do presente estudo. RESULTADOS: Foram encontrados 27 artigos com relatos acerca do impacto de interven����es psicoeducacionais em cuidadores de idosos com dem��ncia. Os resultados mais prevalentes desses estudos s��o: melhora do bem-estar dos cuidadores (37% dos estudos); aumento do uso de estrat��gias de enfrentamento (30%); diminui����o de pensamentos disfuncionais (30%); aumento do conhecimento sobre os servi��os dispon��veis (19%); melhora da autoefic��cia (15%); e aumento de habilidades para o cuidado (11%). A abordagem psicoeducacional descrita nos estudos �� do ��mbito informativo, cognitivo-comportamental, com t��cnicas de gerenciamento de estresse e de emo����es; t��cnicas de resolu����o de problemas e apoio emocional. CONCLUS��O: A interven����o psicoeducacional contribui significativamente para a melhora do bem-estar do cuidador, contudo ainda �� necess��ria uma padroniza����o dessa abordagem, em termos de estrutura, dura����o e conte��dos ministrados, para que haja evid��ncias mais precisas do efeito desse tipo de interven����o.

Fibrila����o atrial e dem��ncia: resultados do S��o Paulo ageing & health study

FUNDAMENTO: A fibrila����o atrial �� um fator de risco controverso para dem��ncia. OBJETIVO: O objetivo deste estudo �� avaliar a associa����o entre fibrila����o atrial e dem��ncia em participantes do S��o Paulo Ageing & Health. M��TODOS: O S��o Paulo Ageing & Health �� um estudo transversal, de base populacional, de idosos residentes em um uma regi��o de baixa renda da cidade de S��o Paulo, Brasil. Diagn��stico de dem��ncia foi realizado de acordo com o protocolo do grupo 10/66, com base em crit��rios do Manual de Diagn��stico e Estat��stica das Perturba����es Mentais (DSM-IV). O diagn��stico de fibrila����o atrial foi feito por eletrocardiograma de 12 deriva����es, avaliado por dois cardiologistas. Dados demogr��ficos e de fatores de risco cardiovasculares tamb��m foram obtidos. RESULTADOS: A dem��ncia foi diagnosticada em 66 (4,3%) e fibrila����o atrial em 36 (2,4%) de 1.524 participantes com um eletrocardiograma v��lido. A raz��o de chances bruta para dem��ncia em participantes com fibrila����o atrial foi 2,8 (intervalo de confian��a [IC] 95%: 1,0-8,1; p = 0,06) em compara����o com indiv��duos sem fibrila����o atrial. Rela����o positiva foi encontrada em mulheres (RC 4,2; IC 95%: 1,2-15,1; p = 0,03). Ap��s ajuste para idade, no entanto, essa associa����o tornou-se n��o significativa (RC 2,2, IC 95%: 0,6-8,9; p = 0,26). CONCLUS��O: N��o houve associa����o independente entre a fibrila����o atrial e dem��ncia nessa amostra. A preval��ncia da fibrila����o atrial pode ser baixa nesta popula����o em virtude da mortalidade cardiovascular prematura.

Untersuchungen zur Beteiligung der Preseniline an den molekularen Mechanismen der Amyloid-�� Entstehung

ZusammenfassungMorbus Alzheimer ist eine progressive, neurodegenerative Erkrankung, die weltweit die h��ufigste Form der Demenz darstellt und im mittleren bis sp��ten Lebensabschnitt auftritt. Die neuropathologischen Merkmale beinhalten das Auftreten von extrazellul��ren Ablagerungen aus fibrillogenem A��42 Peptiden in senilen Plaques und intraneuronalen Akkumulationen von hyperphosphoryliertem Tau in sogenannten neurofibrill��ren B��ndeln. Obwohl die meisten Alzheimer F��lle sporadisch und Alters-assoziiert auftreten, gibt es eine autosomal dominant vererbte Form (FAD; Familial Alzheimer Disease), die schon in einem fr��hen Lebensabschnitt (ab 28 Jahren) ausbrechen kann. Diese aggressive Alzheimer Form wird durch Mutationen im Amyloid-Precursor-Protein-Gen (APP) oder den Presenilin-Genen (PS-1 und PS-2) ausgel��st. Die Presenilin (PS) Proteine sind entscheidend an der Entstehung von A�� beteiligt. So erh��hen FAD-assoziierte Mutationen in PS-1 und PS-2 die Bildung von A��42. Au��erdem verhindern sowohl homozygote PS-1 Null-Mutationen (PS-1-/-) in transgenen M��usen, als auch dominant negative PS-1 Mutationen in Kulturzellen die Ab Bildung. Diese Belege sprechen f��r die zur Zeit favorisierte Amyloid Hypothese, in der die toxische Wirkung des A��-Peptides in der Entstehung der Alzheimer Erkrankung eine zentrale Rolle einnimmt. Die y-Sekretase ist eine Protease, deren Aktivit��t f��r die Entstehung von Ab aus dem Vorl��uferprotein APP essentiell ist. Damit bildet sie einen m��glichen Ansatzpunkt, um grundlegend in den Proze�� der Ab Bildung einzugreifen. Die y-Sekretase ist allerdings noch nicht identifiziert oder kloniert. Es gibt Hinweise, da�� die Preseniline y-Sekretase Aktivit��t besitzen k��nnten. Diese Theorie ist bis heute jedoch nicht eindeutig belegt. In dieser Arbeit sollten die molekularen Mechanismen der Ab Entstehung und insbesondere die Beteiligung der Preseniline an diesem Proze�� untersucht werden. Dazu wurde zun��chst die subzellul��re Verteilung der endogenen Preseniline analysiert. Es konnte erstmalig ein Unterschied in der subzellul��ren Verteilung zwischen PS-1 und PS-2 festgestellt werden. PS-1 war vorwiegend im ER lokalisiert, wogegen PS-2 stark im Golgi-Apparat angereichert war. Im zweiten Teil der Arbeit wurde nach m��glichen Interaktionen der Preseniline mit C-terminalen APP Fragmenten gesucht, die die Substrate der y-Sekretase darstellen. Es konnte gezeigt werden, da�� die Preseniline mit einem 21 kDa gro��en C-terminalen APP Fragment interagieren. Dabei band die Mutante-Form der Preseniline mehr C-terminales APP Fragment als die Wildtyp-Form. Weiterhin wurde ein zellfreies System zur indirekten Bestimmung der y-Sekretase Aktivit��t etabliert. Mit Hilfe dieses Systems wird es m��glich, Inhibitoren der y-Sekretase zu identifizieren. Die Spezifit��t des zellfreien Testsystems konnte dadurch deutlich gemacht werden, da�� das PS-1, das schon in Zellkultur als essentielle Proteinkomponente zur Entstehung von A�� beschrieben wurde, auch in diesem zellfreien y-Sekretase System notwendig war. Allgemeine Proteaseinhibitoren, die alle bekannten Proteasemechanismen abdeckten, zeigten keinen Einflu�� auf die de novo Bildung von A��. Es konnte festgestellt werden, da�� neben der y-Sekretase als A�� produzierende Protease auch A�� abbauende Proteasen vorlagen. Das pH-Optimum der y-Sekretase wurde im neutralen Bereich festgestellt. Weiterhin konnte gezeigt werden, da�� die y-Sekretase eine transmembrane oder zumindest membranassoziierte Protease ist, die keine cytosolischen Komponenten ben��tigt.

Sindrome di Down e fattori di rischio nel declino neurocognitivo

Down syndrome (DS) or Trisomy 21, occurring in 1/700 and 1/1000 livebirths, is the most common genetic disorder, characterized by a third copy of the human chromosome 21 (Hsa21). DS is associated with various defects, including congenital heart diseases, craniofacial abnormalities, immune system dysfunction, mental retardation (MR), learning and memory deficiency. The phenotypic features in DS are a direct consequence of overexpression of genes located within the triplicated region on Hsa21. In addition to developmental brain abnormalities and disabilities, people with DS by the age of 30-40 have a greatly increased risk of early-onset of Alzheimer���s disease (AD) and an apparent tendency toward premature aging. Many of the immunological anomalies in DS can be enclosed in the spectrum of multiple signs of early senescence. People with DS have an increased vulnerability to oxidative damage and many factors, including amyloid beta protein (Abeta), genotype ApoE4, oxidative stress, mutations in mitochondrial DNA (mtDNA), impairment of antioxidant enzymes, accelerated neuronal cell apoptosis, are related to neuronal degeneration and early aging in DS. SUBJECTS and METHODS: Since 2007 a population of 50 adolescents and adults with DS, 26 males and 24 females (sex-ratio: M/F = 1.08), has been evaluated for the presence of neurological features, biomarkers and genetic factors correlated with neuronal degeneration and premature aging. The control group was determined by the mother and the siblings of the patients. A neuropsychiatric evaluation was obtained from all patients. The levels of thyroid antibodies (antiTg and antiTPO) and of some biochemical markers of oxidative stress, including homocysteine (tHcy), uric acid, cobalamin, folate were measured. All patients, the mother and the siblings were genotyped for ApoE gene. RESULTS: 40% of patients, with a mild prevalence of females aged between 19 and 30 years, showed increased levels of antiTg and antiTPO. The levels of tHcy were normal in 52% patients and mildly increased in 40%; hyperomocysteinemia was associated with normal levels of thyroid antibodies in 75% of patients (p<0.005). The levels of uric acid were elevated in 26%. Our study showed a prevalence of severe MR in patients aged between 1-18 years and over 30 years. Only 3 patients, 2 females and one male, over 30 years of age, showed dementia. According to the literature, the rate of Down left-handers was high (25%) compared to the rest of population and the laterality was associated with increased levels of thyroid antibodies (70%). 21.5% of patients were ApoE4 positive (ApoE4+) with a mean/severe MR. CONCLUSIONS: Until now no biochemical evidence of oxidative damage and no deficiency or alteration of antioxidant function in our patients with DS were found. mtDNA sequencing could show some mutations age-related and associated with oxidative damage and neurocognitive decline in the early aging of DS. The final aim is found predictive markers of early-onset dementia and a target strategy for the prevention and the treatment of diseases caused by oxidative stress. REFERENCES: 1) Rachidi M, Lopes C: ���Mental retardation and associated neurological dysfunctions in Down syndrome: a consequence of dysregulation in critical chromosome 21 genes and associated molecular pathways.��� - Eur J Paediatr Neurol. May;12(3):168-82 (2008). 2) Lott IT, Head E: ���Down syndrome and Alzheimer's disease: a link between development and aging.��� - Ment Retard Dev Disabil Res Rev, 7(3):172-8 (2001). 3) Lee HC, Wei YH: ���Oxidative Stress, Mitochondrial DNA Mutation, and Apoptosis in Aging.��� - Exp Biol Med (Maywood), May;232(5):592-606 (2007).

Longevity and stroke: a study on 1.176 GeHA 90+ Italian sibs

Preface: The improvements of the social-environmental conditions, and medical cares and the quality of life caused a general improvement of the health status of the population, with a consequent reduction of the overall morbidity and mortality, resulting in an increase of life expectancy that has rose dramatically in the last century. Stroke represents the 3rd cause of death and 1st cause of disability in Europe and in Italy. Aim: The aim of this research is to explore the prevalence of stroke in 1.176 90+ Italian sibs, collected from the north, centre and south of the peninsula, and examine the presence of functional and cognitive disability in the stroke affected sibs. Materials and Methods: We divided our sample in three main categories a)Stroke free(960 subjects, 88.72%), b)Young age stroke, reported age of Stroke incidence < 85 y.o.(42 subjects, 3.88%), c)Old age stroke, reported age of Stroke incidence ��� 85y.o.(80 subjects, 7.39%). We examine cognitive impairment using the MMSE and functional disability using the ADL scale, the chair stand and hand-grip test. The three groups for each test have been analysed according the following parameters: age at interview, sex, ability to understand the questions, can the participant walk 500 m without help, smoke habit, alcohol daily consumption, presence of serious memory impairments (e.g. dementia), Daily Exercise or daily light housework, History of arthritis. Results: After performing mulrivariate analysis, amazingly the young ictus group had worst performance in all the cognitive and functional variables.

Risk factors for postoperative delirium in the elderly

Background: Delirium is defined as an acute disorder of attention and cognition. Delirium is common in hospitalized elderly patient and is associated with increased morbidity, length of stay and patient care costs. Although Delirium can develop at any time during hospitalization, it typically presents early in the post-operative period (Post-Operative Delirium, POD) in the surgery context. The molecular mechanism and possible genetics basis of POD onset are not known, as well as all the risk factors are not completely defined. Our hypothesis is that genetic risk factor involving the inflammatory response could have possible effects on the immunoneuroendocrine system. Moreover, our previous data (inflamm-aging) suggest that aging is associated with an increase of inflammatory status, favouring age-related diseases such as neurodegenerative diseases, frailty, depression among other. Some pro-inflammatory or anti-inflammatory cytokines, seem to play a crucial role in increasing the inflammatory status and in the communication and regulation of immunoneuroendocrine system. Objective: this study evaluated the incidence of POD in elderly patients undergoing general surgery, clinical/physical and psychological risk factors of POD insurgency and investigated inflammatory and genetic risk factors. Moreover, this study evaluated the consequence of POD in terms of institutionalization, development of permanent cognitive dysfunction or dementia and mortality Methods: patients aged over 65 admitted for surgery at the Urgency Unit of S.Orsola-Malpighi Hospital were eligible for this case���control study. Risk factors significantly associated with POD in univariate analysis were entered into multivariate analysis to establish those independently associated with POD. Preoperative plasma level of 9 inflammatory markers were measured in 42 control subjects and 43 subjects who developed POD. Functional polymorphisms of IL-1 �� , IL-2, IL-6, IL-8, IL-10 and TNF-alpha cytokine genes were determined in 176 control subjects and 27 POD subjects. Results: A total of 351 patients were enrolled in the study. The incidence of POD was 13���2 %. Independent variables associated with POD were: age, co-morbidity, preoperative cognitive impairment, glucose abnormalities. Median length of hospital stay was 21 days for patients with POD versus 8 days for control patients (P < 0���001). The hospital mortality rate was 19 and 8���4 % respectively (P = 0���021) and mortality rate after 1 year was also higher in POD (P= 0.0001). The baseline of IL-6 concentration was higher in POD patients than patients without POD, whereas IL-2 was lower in POD patients compared to patients without POD. In a multivariate analysis only IL-6 remained associated with POD. Moreover IL-6, IL-8 and IL-2 are associated with co-morbidity, intra-hospital mortality, compromised functional status and emergency admission. No significant differences in genotype distribution were found between POD subjects and controls for any SNP analyzed in this study. Conclusion: In this study we found older age, comorbidity, cognitive impairment, glucose abnormalities and baseline of IL-6 as independent risk factors for the development of POD. IL-6 could be proposed as marker of a trait that is associated with an increased risk of delirium; i.e. raised premorbid IL-6 level predict for the development of delirium.

Down Syndrome: Neuropsychological phenotype and mitochondrial DNA

Introduction. Down Syndrome (DS) is the most known autosomal trisomy, due to the presence in three copies of chromosome 21. Many studies were designed to identify phenotypic and clinical consequences related to the triple gene dosage. However, the general conclusion is a senescent phenotype; in particular, the most features of physiological aging, such as skin and hair changes, vision and hearing impairments, thyroid dysfunction, Alzheimer-like dementia, congenital heart defects, gastrointestinal malformations, immune system changes, appear in DS earlier than in normal age-matched subjects. The only established risk factor for the DS is advanced maternal age, responsible for changes in the meiosis of oocytes, in particular the meiotic nondisjunction of chromosome 21. In this process mitochondria play an important role since mitochondrial dysfunction, due to a variety of extrinsic and intrinsic influences, can profoundly influence the level of ATP generation in oocytes, required for a correct chromosomal segregation. Aim. The aim of this study is to investigate an integrated set of molecular genetic parameters (sequencing of complete mtDNA, heteroplasmy of the mtDNA control region, genotypes of APOE gene) in order to identify a possible association with the early neurocognitive decline observed in DS. Results. MtDNA point mutations do not accumulate with age in our study sample and do not correlate with early neurocognitive decline of DS subjects. It seems that D-loop heteroplasmy is largely not inherited and tends to accumulate somatically. Furthermore, in our study sample no association of cognitive impairment and ApoE genotype is found. Conclusions. Overall, our data cast some doubts on the involvement of these mutations in the decline of cognitive functions observed in DS.

Longitudinal evolution of cognitive functions in patients with multiple system atrophy: a prospective study

Introduction and Background: Multiple system atrophy (MSA) is a sporadic, adult-onset, progressive neurodegenerative disease characterized clinically by parkinsonism, cerebellar ataxia, and autonomic failure. We investigated cognitive functions longitudinally in a group of probable MSA patients, matching data with sleep parameters. Patients and Methods: 10 patients (7m/3f) underwent a detailed interview, a general and neurological examination, laboratory exams, MRI scans, a cardiovascular reflexes study, a battery of neuropsychological tests, and video-polysomnographic recording (VPSG). Patients were revaluated (T1) a mean of 16��5 (range: 12-28) months after the initial evaluation (T0). At T1, the neuropsychological assessment and VPSG were repeated. Results: The mean patient age was 57.8��6.4 years (range: 47-64) with a mean age at disease onset of 53.2��7.1 years (range: 43-61) and symptoms duration at T0 of 60��48 months (range: 12-144). At T0, 7 patients showed no cognitive deficits while 3 patients showed isolated cognitive deficits. At T1, 1 patient worsened developing multiple cognitive deficits from a normal condition. At T0 and T1, sleep efficiency was reduced, REM latency increased, NREM sleep stages 1-2 slightly increased. Comparisons between T1 and T0 showed a significant worsening in two tests of attention and no significant differences of VPSG parameters. No correlation was found between neuropsychological results and VPSG findings or RBD duration. Discussion and Conclusions: The majority of our patients do not show any cognitive deficits at T0 and T1, while isolated cognitive deficits are present in the remaining patients. Attention is the cognitive function which significantly worsened. Our data confirm the previous findings concerning the prevalence, type and the evolution of cognitive deficits in MSA. Regarding the developing of a condition of dementia, our data did not show a clear-cut diagnosis of dementia. We confirm a mild alteration of sleep structure. RBD duration does not correlate with neuropsychological findings.

Aktivierung der alpha-Sekretase ADAM10 als neuer therapeutischer Ansatz zur Behandlung der Alzheimer-Erkrankung

Die Stimulation der APP-prozessierenden ��-Sekretase ADAM10 er��ffnet eine vielversprechende M��glichkeit zur medizinischen Behandlung der Alzheimer-Krankheit. In dieser Arbeit wurden drei unterschiedliche Strategien zur therapeutischen Aktivierung von ADAM10 verfolgt: Die Aktivierung des G-Protein-gekoppelten Rezeptors PAC1 durch PACAP, die Gentherapie mit ADAM10-cDNA und die ADAM10-Promotorstimulation durch Retinoid-Rezeptor-Aktivierung. PACAP-38 stimuliert die ��-Sekretase-vermittelte APPs��-Sekretion in humanen Neuroblastomzellen. Durch Aktivierung des PAC-1-Rezeptors via intranasal verabreichtem PACAP-38, konnte eine erh��hte ��-sekretorische APP-Prozessierung bzw. verminderte Ablagerung von amyloiden Plaques in M��usen gezeigt werden. Weiterhin sollte durch Immunoliposomen-basierte Transfektion die humane ADAM10-cDNA in den Neuronen der Maus ��berexprimiert werden. Hief��r wurde die DNA in Liposomen eingeschlossen, welche an ihrer Oberfl��che mit anti-Transferrin-Antik��rpern zur ��berwindung der Blut-Hirn-Schranke gekoppelt waren. F��r die Herstellung des DNA-Transportsystems wurden die Einzelschritte wie DNA-Einschluss mit einem Reportergen-Vektor, Konjugation mit verschiedenen Antik��rpern und Gr����e der Liposomen erprobt und optimiert. Es konnte allerdings weder in vitro noch in vivo eine Immunoliposomen-vermittelte Transfektion nachgewiesen werden. In dieser Arbeit wurde zudem die Retinoid-basierte Expressionssteigerung von ADAM10 untersucht. Daf��r wurden die beiden potentiellen Retinoid-Rezeptor-Bindestellen auf dem ADAM10-Promotor durch Verwendung selektiver nukle��rer Rezeptor-Agonisten charakterisiert. Hierbei konnte erstmals gezeigt werden, dass der ADAM10-Promotor durch ein Dimer der nukle��ren Rezeptoren RAR und RXR aktiviert wird, wodurch eine erh��hte ��-sekretorischen APP-Prozessierung in Neuroblastoma-Zellen resultiert. Weiterhin konnte gezeigt werden, dass die RAR/RXR-Heterodimeraktivierung sowohl auf dem humanen wie auf dem murinen ADAM10-Promotor identisch ist, so dass am Mausmodell entwickelte Retinoid-basierte Therapien auf den Menschen ��bertragbar sind. F��r das Modell einer solchen Therapie wurde Acitretin verwendet, welches f��r die medizinische Behandlung humaner Hautkrankheiten seit Jahrzehnten eingesetzt wird. In dieser Arbeit konnte erstmals gezeigt werden, dass Acitretin in humanen und murinen Neuroblastoma-Zellen die Menge an ADAM10 erh��ht, wodurch die ��-sekretorische APP-Prozessierung gesteigert wird. Zudem wurden M��use mit Acitretin oral, subcutan und intranasal behandelt, wobei jedoch weder eine Ver��nderung in der APP-Prozessierung noch der Blut-Hirn-Transport von Acitretin eindeutig belegt werden konnten. Dennoch erschlie��t die ��-Sekretase-erh��hende Eigenschaft von Acitretin einen neuen Therapieansatz, zur Behandlung von Demenzformen vom Typ des Morbus Alzheimer.

Biomolecular studies in Alzheimer���s Disease models: investigations in vitro and in vivo

The Alzheimer���s disease (AD), the most prevalent form of age-related dementia, is a multifactorial and heterogeneous neurodegenerative disease. The molecular mechanisms underlying the pathogenesis of AD are yet largely unknown. However, the etiopathogenesis of AD likely resides in the interaction between genetic and environmental risk factors. Among the different factors that contribute to the pathogenesis of AD, amyloid-beta peptides and the genetic risk factor apoE4 are prominent on the basis of genetic evidence and experimental data. ApoE4 transgenic mice have deficits in spatial learning and memory associated with inflammation and brain atrophy. Evidences suggest that apoE4 is implicated in amyloid-beta accumulation, imbalance of cellular antioxidant system and in apoptotic phenomena. The mechanisms by which apoE4 interacts with other AD risk factors leading to an increased susceptibility to the dementia are still unknown. The aim of this research was to provide new insights into molecular mechanisms of AD neurodegeneration, investigating the effect of amyloid-beta peptides and apoE4 genotype on the modulation of genes and proteins differently involved in cellular processes related to aging and oxidative balance such as PIN1, SIRT1, PSEN1, BDNF, TRX1 and GRX1. In particular, we used human neuroblastoma cells exposed to amyloid-beta or apoE3 and apoE4 proteins at different time-points, and selected brain regions of human apoE3 and apoE4 targeted replacement mice, as in vitro and in vivo models, respectively. All genes and proteins studied in the present investigation are modulated by amyloid-beta and apoE4 in different ways, suggesting their involvement in the neurodegenerative mechanisms underlying the AD. Finally, these proteins might represent novel potential diagnostic and therapeutic targets in AD.

Einfluss der Modulation von P-Glykoprotein (P-gp) auf die Verf��gbarkeit und Wirksamkeit der pharmakologischen Behandlung psychiatrischer Erkrankungen im Tiermodell

P-Glykoprotein (P-gp) ist ein ATP-verbrauchender Transporter, der in Organschranken exprimiert wird, um Fremdstoffe auszuschleusen, darunter auch Psychopharmaka. Im Rahmen dieser Arbeit wurde im Tiermodell der Maus untersucht, welche pharmakokinetischen und pharmakodynamischen Konsequenzen sich bei Verabreichung von Risperidon als P-gp Modellsubstrat ergeben, wenn die Expression von P-gp induziert wird. Als potenzielle Induktoren wurden Dexamethason, Rifampicin, Quercetin, 5-Pregnen-3��-ol-20-on-16��-Carbonitril (PCN) und Acitretin gepr��ft. Es konnte gezeigt werden, dass alle Substanzen die Verteilung von Risperidon und seinem aktiven Metaboliten 9-Hydroxyrisperidon beeinflussten. W��hrend sich f��r Quercetin und Acitretin leichte P-gp inhibitorische Eigenschaften ergaben, die an Hand von erh��hten Konzentrationen von Risperidon und 9-Hydroxyrisperidon gezeigt werden konnten, f��hrten die bekannten P-gp Induktoren Rifampicin, Dexamethason und PCN zu verringerten Konzentrationen im Vergleich zur Kontrollgruppe. Durch Western Blot Untersuchungen wurde best��tigt, dass die Induktoren die P-gp Expression im Hirngewebe tendenziell steigerten. Dies sprach daf��r, dass bei Verabreichung einer Komedikation, die P-gp induziert, mit einer ver��nderten Verteilung von P-gp Substraten zu rechnen ist. Dar��ber hinaus konnte nachgewiesen werden, dass durch eine Hemmung bzw. Induktion von P-gp nicht nur die Pharmakokinetik, sondern auch die Pharmakodynamik von Risperidon und 9-Hydroxyrisperidon ver��ndert wird. Dies wurde durch verhaltenspharmakologische Untersuchungen gezeigt. Durch Risperidon induzierte motorische Effekte auf dem RotaRod waren nach Induktion von P-gp abgeschw��cht. Dies zeigte sich auch f��r Haloperidol, welches kein Substrat ist. Da P-gp abh��ngige Effekte in diesem Fall keine bedeutende Rolle spielen, ist davon auszugehen, dass neben der Induktion von P-gp an der Blut-Hirn Schranke auch andere Mechanismen wie z.B. eine Induktion von Enzymen der CYP-Familie an den beobachteten Effekten beteiligt sind. Bei Untersuchungen von kognitiven Leistungen in der Barnes Maze konnte gezeigt werden, dass Haloperidol im Gegensatz zu Risperidon das Lernverhalten negativ beeinflussen kann. Eine P-gp Induktion schien jedoch keinen deutlichen Einfluss auf das Lernverhalten unter Antipsychotika-Gabe zu haben und sprach vielmehr f��r substanzabh��ngige Effekte der einzelnen Antipsychotika bzw. P-gp Modulatoren. Zusatzuntersuchungen zur Hirng��ngigkeit von Acitretin, einem synthetischen Retinoid, welches derzeit als potenzielles Antidementivum gepr��ft wird, konnten belegen, dass es die Blut-Hirn Schranke ��berwindet. Bereits 1h nach Injektion war Acitretin in hoher Konzentration im Gehirn nachweisbar. Durch die Analyse zur Verteilung von Acitretin in Hirngewebe und Serum von P-gp Wildtyp und P-gp doppel knockout M��usen konnte belegt werden, dass Acitretin nicht P-gp abh��ngig transportiert wird. Die Daten insgesamt betrachtet, lassen den Schluss zu, dass durch Verabreichung von Medikamenten, die P-gp Modulatoren sind, bei Antipsychotika mit pharmakokinetischen Interaktionen zu rechnen ist, welche die Wirksamkeit der Medikamente einschr��nken k��nnen.

L'utilizzo dei casi di studio per favorire l'apprendimento di metodologie e strumenti per lo sviluppo organizzativo o di percorsi di cura nelle aziende sanitarie

La formazione, in ambito sanitario, �� considerata una grande leva di orientamento dei comportamenti, ma la metodologia tradizionale di formazione frontale non �� la pi�� efficace, in particolare nella formazione continua o ���long-life education���. L���obiettivo primario della tesi �� verificare se l���utilizzo della metodologia dello ���studio di caso���, di norma utilizzata nella ricerca empirica, pu�� favorire, nel personale sanitario, l���apprendimento di metodi e strumenti di tipo organizzativo-gestionale, partendo dalla descrizione di processi, decisioni, risultati conseguiti in contesti reali. Sono stati progettati e realizzati 4 studi di caso con metodologia descrittiva, tre nell���Azienda USL di Piacenza e uno nell���Azienda USL di Bologna, con oggetti di studio differenti: la continuit�� di cura in una coorte di pazienti con stroke e l���utilizzo di strumenti di monitoraggio delle condizioni di autonomia; l���adozione di un approccio ���patient-centred��� nella presa in carico domiciliare di una persona con BPCO e il suo caregiver; la percezione che caregiver e Medici di Medicina Generale o altri professionisti hanno della rete aziendale Demenze e Alzheimer; la ricaduta della formazione di Pediatri di Libera Scelta sull���attivit�� clinica. I casi di studio sono stati corredati da note di indirizzo per i docenti e sono stati sottoposti a quattro referee per la valutazione dei contenuti e della metodologia. Il secondo caso �� stato somministrato a 130 professionisti sanitari all���interno di percorso di valutazione delle competenze e dei potenziali realizzato nell���AUSL di Bologna. I referee hanno commentato i casi e gli strumenti di lettura organizzativa, sottolineando la fruibilit��, approvando la metodologia utilizzata, la coniugazione tra ambiti clinico-assistenziali e organizzativi, e le teaching note. Alla fine di ogni caso �� presente la valutazione di ogni referee.

Oxidativer Stress als Modulator der NMDA-Rezeptorexpression auf zerebrovaskul��ren Endothelzellen

Oxidativer Stress in Form reaktiver Sauerstoffspezies (ROS) und Exzitotoxizit��t durch supraphysiologische Konzentrationen des Neurotransmitters Glutamat sind nicht nur beteiligt an der Pathogenese vielz��hliger neurodegenerativer Erkrankungen wie Schlaganfall, Hirntrauma, Alzheimer Demenz oder Multipler Sklerose, sondern spielen zudem eine Schl��sselrolle im dort beobachteten Zusammenbruch der Blut-Hirn-Schranke. Glutamat f��hrt durch Stimulation neuronaler und endothelialer NMDA-Rezeptoren zu einer Generierung von ROS. Nicht verfolgt worden war bisher, welche Auswirkungen ROS umgekehrt auch auf den NMDA-Rezeptor haben k��nnten. Im Rahmen der vorliegenden Arbeit wurde daher untersucht, ob und in welcher Weise die Exposition gegen��ber reaktiven Sauerstoffspezies einen Einfluss auf die Expression und Aktivierbarkeit von NMDA-Rezeptoren auf zerebrovaskul��ren Endothelzellen aus��bt.rnEs konnte zun��chst die Expression der funktionell obligaten NR-1 Untereinheit des NMDA-Rezeptors auf der verwendeten Zelllinie b.End3 mittels Immunfluoreszenz-Mikroskopie gesichert werden. Ein Nachweis von mRNA f��r die Untereinheiten NR1 und NR2B, C und D erfolgte mittels RT-PCR. In der Analyse der replizierten RNA zeigten sich Hinweise f��r eine heterogene Komposition der exprimierten endothelialen NMDA-Rezeptoren.rnEs konnte weiter mit Hilfe der In-Cell-Western-Technik gezeigt werden, dass die Expression des NMDA-Rezeptors durch transiente Stimulation mit reaktiven Sauerstoffspezies im Sinne einer Heraufregulation moduliert werden kann. Die Stimulation der Zellen mit den reaktiven Sauerstoffspezies O2-, ONOO- und H2O2 f��hrte dabei im Experiment zu einer deutlichen Zunahme der NR1-Expression, die sp��testens nach 72 Stunden h��chst signifikant war.rnUm zu ��berpr��fen, welche Bedeutung diese ��berexpression f��r die Integrit��t der Blut-Hirn-Schranke unter den exzitotoxischen Bedingungen hoher Glutamatkonzentrationen haben k��nnte, wurde mit Hilfe des ECIS-Systems (���Electrical Cell-Substrate Impedance Sensing���) die Impedanz ROS-pr��exponierter Endothelmonolayer gemessen. Auf Rezeptorstimulation mit dem spezifischen Agonisten NMDA reagierten die vorbehandelten Gruppen mit einem Abfall der Impedanz gegen��ber der nicht vorbehandelten Kontrolle.rnrnDie vorliegenden Ergebnisse zeigen, dass ROS in der Lage sind, funktionelle endotheliale NMDA-Rezeptoren zu induzieren und auf diesem Weg zu einem verst��rkten Abfall der BHS-Integrit��t unter den Bedingungen exzitotoxischen und oxidativen Stresses f��hren. Dies stellt einen neuen Mechanismus zur Erkl��rung der Pathogenese des Blut-Hirn-Schrankenversagens dar.

Sleep motor activity in parkinsonian syndromes at onset: a prospective study to determine potential diagnostic and prognostic markers

Aim of this study is to describe the possible diagnostic value of sleep disturbances in the differential diagnosis of neurodegenerative diseases characterized by parkinsonism at onset. 42 consecutive patients with parkinsonian features and disease duration up to 3 years were included in the BO-ProPark study. Each patient was evaluated twice, at baseline (T0) and 16 months later (T1). Patients were diagnosed as Parkinson disease (PD, 27 patients), PD plus (PD with cognitive impairment/dementia or dysautonomia, 4 patients) and parkinsonian syndrome (PS, 11 patients). All patients underwent a full night video-polysomnography scored by a neurologist blinded to the clinical diagnosis. Sleep efficiency and total sleep time were reduced in all patients; wake after sleep onset was higher in patients with atypical parkinsonisms than in PD patients. No significant differences between groups of patients were detected in other sleep parameters. The mean percentage of epochs with enhanced tonic muscle EMG activity during REM sleep was higher in PD plus and PS than in PD. No difference in phasic muscle EMG activity during REM sleep was seen between the two groups. REM behaviour disorder was more frequent in PD plus and PS than in PD patients. Our data suggest that REM sleep motor control is more frequently impaired at disease onset in patients with PS and PD plus compared to PD patients. The presence of RBD or an enhanced tonic muscle EMG activity in a patient with recent onset parkinsonian features should suggest a diagnosis of atypical parkinsonism, rather than PD. More data are needed to establish the diagnostic value of these features in the differential diagnosis of parkinsonisms. The evaluation of sleep disorders may be a useful tool in the differential diagnosis of parkinsonism at onset.