Alzheimer Disease: Hock C

Nitsch RM, Hock C. · Division of Psychiatry Research, University of Zurich, Switzerland. · Neurotherapeutics. · Pubmed #18625453 No free full text.

Abstract: More than 10 clinical trials of Abeta immunotherapy are currently underway in patients with Alzheimer's disease (AD). The aim is to identify safe approaches for the efficacious antibody-mediated removal of brain beta-amyloid or its neurotoxic oligomeric precursors consisting of aggregated amyloid beta-peptide (Abeta). Initial experimental and neuro-pathological evidence for clearance of brain beta-amyloid in response to Abeta immunotherapy is associated with structural and functional rescue of neurons, as well as initial signs of clinical stabilization and reduced rates of dementia progression. For the next steps in the future improvement of Abeta immunotherapy, major challenges in pharmacokinetics, safety, and tolerability need to be addressed. These include the low penetrations rates of IgG molecules through the blood-brain barrier, possible reductions in brain volume, the possibility of autoimmune disease related to unwanted cross-reactivity with endogenous antigens on physiological structures, micro-hemorrhages related to cross-reaction with pre-existing vascular amyloid pathology, possible relocalization of Abeta from beta-amyloid plaques to brain blood vessels resulting in increased amyloid angiopathy, and the lacking activity of Abeta antibodies on pre-existing neurofibrillary tangle pathology, as well as the lacking molecular identification of the forms of Abeta to be therapeutically targeted. The solutions to these problems will be guided by the fine lines between tolerance and immunity against physiological and pathological structures, respectively, as well as by the understanding of the pathogenic transition of soluble Abeta into toxic oligomeric aggregation intermediates in the dynamic equilibrium of beta-amyloid fibril assembly. Provided that the ongoing and planned clinical trials address these issues in a timely manner, there is a good chance for Abeta immunotherapy to be one of the first disease-modifying therapies of Alzheimer's disease to be introduced into clinical practice.

Hock C, Nitsch RM. · Division of Psychiatry Research, University of Zurich, Zurich, Switzerland. · Neurodegener Dis. · Pubmed #16909009 No free full text.

Abstract: Clinical observations with AN-1792 using tissue amyloid plaque immunoreactivity (TAPIR) analyses established for the first time evidence in humans that antibodies against beta-amyloid-related epitopes are capable of slowing progression in Alzheimer's disease. Antibodies derived upon TAPIR assay selection may specifically target the pathologic neoepitopes of aggregated A beta species present in amyloid plaques and some of their aggregated, protofibrillar and low molecular weight oligomeric precursors. We briefly summarize here how the proof of concept was established and why it provides the basis for a potential cure for Alzheimer's disease.

Wiltfang J, Lewczuk P, Riederer P, Grünblatt E, Hock C, Scheltens P, Hampel H, Vanderstichele H, Iqbal K, Galasko D, Lannfelt L, Otto M, Esselmann H, Henkel AW, Kornhuber J, Blennow K. · Molecular Neurobiology Lab, Department of Psychiatry and Psychotherapy, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany. · World J Biol Psychiatry. · Pubmed #16156480 No free full text.

Abstract: Aging of population, and increasing life expectancy result in an increasing number of patients with dementia. This symptom can be a part of a completely curable disease of the central nervous system (e.g, neuroinflammation), or a disease currently considered irreversible (e.g, Alzheimer's disease, AD). In the latter case, several potentially successful treatment approaches are being tested now, demanding reasonable standards of pre-mortem diagnosis. Cerebrospinal fluid and serum analysis (CSF/serum analysis), whereas routinely performed in neuroinflammatory diseases, still requires standardization to be used as an aid to the clinically based diagnosis of AD. Several AD-related CSF parameters (total tau, phosphorylated forms of tau, Abeta peptides, ApoE genotype, p97, etc.) tested separately or in a combination provide sensitivity and specificity in the range of 85%, the figure commonly expected from a good diagnostic tool. In this review, recently published reports regarding progress in neurochemical pre-mortem diagnosis of dementias are discussed with a focus on an early and differential diagnosis of AD. Novel perspectives offered by recently introduced technologies, e.g, fluorescence correlation spectroscopy (FCS) and surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) are briefly discussed.

Papassotiropoulos A, Hock C, Nitsch RM. · Division of Psychiatry Research, University of Zürich, Switzerland. · Neurobiol Aging. · Pubmed #11754993 No free full text.

Abstract: Alzheimer's disease (AD) is a neurodegenerative disorder that preferentially affects individuals above 60 years, with increasing risk in older ages. Neuropathological hallmarks of AD include brain atrophy, senile plaques, and neurofibrillary tangles. In addition, inflammatory processes frequently accompany the neuropathology of AD. Among several mediators of the inflammatory response, interleukin 6 (IL6) may play a role in these inflammatory processes. Polymorphisms of the IL6 gene are associated with changed IL6 gene expression, and with altered immune responses resulting in such phenotypes as early transplant rejection, the development of anti-histone antibodies in systemic lupus erythematosus, or altered bone resorption in osteoporosis. Recent data suggested that IL6 is also genetically associated with AD, but many questions remain to be answered. Which polymorphic sites can be identified within functional regions of IL6, and how do they affect gene expression, neurobiological function and pathophysiological events in health and AD? Are there interactions of other genes with IL6 that affect the development and progression of AD? Are such interactions additive, sub-additive, synergistic, or epistatic in nature? How do IL6 polymorphisms influence the therapy of AD? Answering some of these questions will be a good start toward assessing the role of IL6 in the genetics of AD.

Hock C, Nitsch RM. · Abteilung für Psychiatrische Forschung, Psychiatrische Universitätsklinik, Universität Zürich. · Praxis (Bern 1994). · Pubmed #10776055 No free full text.

Abstract: Alzheimer's disease is the most common form of dementia in the elderly. This review describes diagnosis, differential diagnosis, etiology and course of Alzheimer's dementia. Genetic and non-genetic risk factors are presented. In addition to the already available symptomatic therapies with acetylcholinesterase-inhibitors, new therapeutic approaches with protective and restorative substances are currently being developed.

Müller-Spahn F, Hock C. · Psychiatrische Universitätsklinik, Basel, Switzerland. · Eur Arch Psychiatry Clin Neurosci. · Pubmed #10654098 No free full text.

Abstract: Due to demographic changes the frequency of dementia is increasing dramatically. About 50-60% of patients with dementia are clinically associated with AD, which is a multifactorial and long-term disease both in clinical and preclinical aspects. Various genetic and non-genetic risk factors play a role in influencing age of onset and disease progression.

Orgogozo JM, Gilman S, Dartigues JF, Laurent B, Puel M, Kirby LC, Jouanny P, Dubois B, Eisner L, Flitman S, Michel BF, Boada M, Frank A, Hock C. · Federation of Neurology, CHU Pellegrin, Bordeaux, France. · Neurology. · Pubmed #12847155 No free full text.

Abstract: BACKGROUND: AD is characterized by cerebral deposition of beta-amyloid plaques with amyloid beta-peptide (Abeta) 42 as the major peptide constituent, along with neurofibrillary tangles and neuronal loss. In transgenic mice, active immunization against Abeta42 removes these plaques and improves cognitive function. A Phase I study in AD patients demonstrated good safety and tolerability of multiple injections of aggregated Abeta42 (AN1792) with QS-21 as adjuvant. METHODS: Three hundred seventy-two patients with mild to moderate AD were randomized to receive IM injections of AN1792 or placebo (4:1) at baseline and at months 1, 3, 6, 9, and 12 in a multicenter Phase II safety, tolerability, and pilot efficacy study. Dosing was terminated after four early reports of meningoencephalitis, but follow-up continued. The study remains blinded, and further results will be reported after its termination. RESULTS: Symptoms and laboratory findings consistent with meningoencephalitis occurred in 18 of 298 (6%) patients treated with AN1792 compared with 0 of 74 on placebo (p = 0.020). Sixteen of the 18 had received two doses, one had received one dose, and one had received three doses of the study drug before symptoms occurred. The median latency from the first and last injections to symptoms was 75 and 40 days. No case occurred later than 6 months after the first immunization. Anti-Abeta42 antibody titers were not correlated with the occurrence or severity of symptoms or relapses. Twelve patients recovered to or close to baseline within weeks, whereas six remain with disabling cognitive or neurologic sequelae. All 18 patients remain alive to date (December 31, 2002), 6 months to >1 year after symptom onset. CONCLUSIONS: Postvaccination meningoencephalitis occurred without clear relation to serum anti-Abeta42 antibody titers. Potential mechanisms such as T-cell and microglial activation may be responsible and are under consideration to develop a safer anti-Abeta immunotherapy for AD.

Hock C, Konietzko U, Streffer JR, Tracy J, Signorell A, Müller-Tillmanns B, Lemke U, Henke K, Moritz E, Garcia E, Wollmer MA, Umbricht D, de Quervain DJ, Hofmann M, Maddalena A, Papassotiropoulos A, Nitsch RM. · Division of Psychiatry Research, University of Zurich, August Forel Strasse 1, 8008 Zurich, Switzerland. · Neuron. · Pubmed #12765607 No free full text.

Abstract: To test whether antibodies against beta-amyloid are effective in slowing progression of Alzheimer's disease, we assessed cognitive functions in 30 patients who received a prime and a booster immunization of aggregated Abeta(42) over a 1 year period in a placebo-controlled, randomized trial. Twenty patients generated antibodies against beta-amyloid, as determined by tissue amyloid plaque immunoreactivity assay. Patients who generated such antibodies showed significantly slower rates of decline of cognitive functions and activities of daily living, as indicated by the Mini Mental State Examination, the Disability Assessment for Dementia, and the Visual Paired Associates Test of delayed recall from the Wechsler Memory Scale, as compared to patients without such antibodies. These beneficial clinical effects were also present in two of three patients who had experienced transient episodes of immunization-related aseptic meningoencephalitis. Our results establish that antibodies against beta-amyloid plaques can slow cognitive decline in patients with Alzheimer's disease.

Hock C, Maddalena A, Raschig A, Müller-Spahn F, Eschweiler G, Hager K, Heuser I, Hampel H, Müller-Thomsen T, Oertel W, Wienrich M, Signorell A, Gonzalez-Agosti C, Nitsch RM. · Division of Psychiatry Research, University of Zürich, Lenggstrasse 31, CH-8029 Zürich, Switzerland. · Amyloid. · Pubmed #12762134 No free full text.

Abstract: The amyloid beta-peptides A beta 40 and A beta 42 are highly amyloidogenic constituents of brain beta-amyloid plaques in Alzheimer's disease (AD). Lowering their formation may be achieved by modulating the activities of proteases that cleave the amyloid precursor protein (A beta PP), including alpha- beta-, and gamma-secretases. Talsaclidine is a functionally selective muscarinic m1 agonist that stimulates non-amyloidogenic alpha-secretase processing in vitro. We compared cerebrospinal fluid (CSF) levels of A beta 40 and A beta 42 measured by ELISA before and at the end of 4 weeks of treatment with talsaclidine. The medication was administered in a double-blind, placebo-controlled, and randomized clinical study to 40 patients with AD. Talsaclidine (n = 34) decreased CSF levels of A beta 42 by a median of 19% (p < 0.001) as compared to baseline. The mean difference between CSF levels of A beta 42 before and after treatment with talsaclidine (n = 34) was -46 +/- 73 (SD) pg/ml as compared to 0 +/- 8 (SD) pg/ml with placebo (n = 6) (p < 0.05). CSF levels of A beta 40 increased during treatment with placebo (n = 6) while they remained stable during treatment with talsaclidine (n = 31) (1.118 +/- 1.710 ng/ml, and -0.170 +/- 0.967 ng/ml, respectively; p < 0.05). These data show that treatment with the m1 agonist talsaclidine reduced A beta peptides, and particularly A beta 42, in AD patients, suggesting it as a potential amyloid lowering therapy of AD.

Hock C, Konietzko U, Papassotiropoulos A, Wollmer A, Streffer J, von Rotz RC, Davey G, Moritz E, Nitsch RM. · Division of Psychiatry Research, University of Zurich, Zurich, Switzerland. · Nat Med. · Pubmed #12379846 No free full text.

Abstract: To characterize antibodies produced in humans in response to Abeta42 vaccination, we carried out immunohistochemical examinations of the brains of both transgenic mice and human patients with beta-amyloid pathology. We collected sera from patients with Alzheimer disease who received a primary injection of pre-aggregated Abeta42 followed by one booster injection in a placebo-controlled study. Antibodies in immune sera recognized beta-amyloid plaques, diffuse Abeta deposits and vascular beta-amyloid in brain blood vessels. The antibodies did not cross-react with native full-length beta-amyloid precursor protein or its physiological derivatives, including soluble Abeta42. These findings indicate that vaccination of AD patients with Abeta42 induces antibodies that have a high degree of selectivity for the pathogenic target structures. Whether vaccination to produce antibodies against beta-amyloid will halt the cognitive decline in AD will depend upon clinical assessments over time.

Wilkinson DG, Passmore AP, Bullock R, Hopker SW, Smith R, Potocnik FC, Maud CM, Engelbrecht I, Hock C, Ieni JR, Bahra RS. · Memory Assessment and Research Centre, Moorgreen Hospital, Southampton, UK. · Int J Clin Pract. · Pubmed #12166542 No free full text.

Abstract: This 12-week, multinational study compared the tolerability and cognitive effects of donepezil (up to 10 mg once daily) and rivastigmine (up to 6 mg twice daily) in 111 patients with mild to moderate Alzheimer's disease. Both medications were administered open label according to recommended dosing regimens from the respective product labelling available during the conduct of the study. More patients in the donepezil group (89.3%) completed the study compared with the rivastigmine group (69.1%; p=0.009), and 10.7% of the donepezil group and 21.8% of the rivastigmine group discontinued due to adverse events (AEs); 87.5% of donepezil-treated patients and 47.3% of rivastigmine-treated patients remained on the maximum approved dose of each drug at the last study visit. Both groups showed comparable improvements on the ADAS-cog administered by raters blind to study medication at weeks 4 and 12. Thus, using the recommended dosing schedules, donepezil was better tolerated with fewer discontinuations due to AEs, and both agents improved cognition to a similar extent.

Hock C, Maddalena A, Heuser I, Naber D, Oertel W, von der Kammer H, Wienrich M, Raschig A, Deng M, Growdon JH, Nitsch RM. · Department of Psychiatry Research, University of Zürich, Lenggstrasse 31, CH-8029 Zürich 8, Switzerland. · Ann N Y Acad Sci. · Pubmed #11193166 No free full text.

Abstract: Brain amyloid load in Alzheimer's disease (AD) is, at least in genetic forms, associated with overproduction of amyloid beta-peptides (A beta). Thus, lowering A beta production is a central therapeutic target in AD and may be achieved by modulating such key enzymes of amyloid precursor protein (APP) processing as beta-, gamma-, and alpha-secretase activities. Talsaclidine is a selective muscarinic M1 agonist that stimulates the nonamyloidogenic alpha-secretase pathway in model systems. Talsaclidine was administered double-blind, placebo-controlled, and randomized to 24 AD patients and cerebrospinal fluid (CSF) levels of total A beta were quantitated before and after 4 weeks of drug treatment. We observed that talsaclidine decreases CSF levels of A beta significantly over time within the treatment group (n = 20) by a median of 16% as well as compared to placebo (n = 4) by a median of 27%. We conclude that treatment with selective M1 agonists may reduce A beta production and may thus be further evaluated as a potential amyloid-lowering therapy of AD.

Burns A, Bernabei R, Bullock R, Cruz Jentoft AJ, Frölich L, Hock C, Raivio M, Triau E, Vandewoude M, Wimo A, Came E, Van Baelen B, Hammond GL, van Oene JC, Schwalen S. · University of Manchester, Manchester, UK. · Lancet Neurol. · Pubmed #19042161 No free full text.

Abstract: BACKGROUND: The efficacy of galantamine has been shown in patients with mild, moderate, and advanced moderate Alzheimer's disease (AD). Here we report its efficacy in patients with severe AD. METHODS: Between December, 2003, and March, 2007, patients aged 84 (SD 6) years with severe AD (mini-mental state examination [MMSE] score 5-12 points), in a nursing home setting were randomly assigned to receive galantamine (n=207), titrated initially to 24 mg/day, or placebo (n=200). Co-primary efficacy measures for cognitive function and ability to undertake normal daily activities were the severe impairment battery (SIB) and the seven-item minimum data set-activities of daily living (MDS-ADL), respectively. Adverse events, vital signs, laboratory parameters, and electrocardiograms were monitored. This trial is registered with ClinicalTrials.gov, number NCT00216593. FINDINGS: 168 of 207 (81%) patients in the galantamine group and 161 of 200 (81%) in the placebo group completed the study. Mean SIB scores increased (improved) by 1.9 (95% CI -0.1 to 3.9) points with galantamine and decreased (worsened) by 3.0 (-5.6 to -0.5) points with placebo (between-group least squares mean difference 4.36, 1.3 to 7.5; p=0.006). Mean MDS-ADL self-performance score worsened by 1.2 (0.6 to 1.8) points and 1.6 (0.8 to 2.3) points, respectively (between-group least squares mean difference -0.41, -1.3 to 0.5; p=0.383). Nominally significant between-group differences in favour of galantamine occurred for the SIB domains of memory (p=0.006), praxis (p=0.010), and visuospatial ability (p=0.002), and for the MDS-ADL subitem locomotion on unit (p=0.021). 183 of 207 patients (88%) who received galantamine and 177 of 200 (89%) who received placebo had adverse events, which were mostly mild to moderate. Eight patients (4%) in the galantamine group and 21 patients (11%) in the placebo group died. ECG abnormalities were similar between the two groups. INTERPRETATION: Galantamine can be started and used safely in elderly patients with severe AD. Galantamine improved cognitive function but failed to significantly improve the co-primary parameter of overall activities of daily living.

De Ferrari GV, Papassotiropoulos A, Biechele T, Wavrant De-Vrieze F, Avila ME, Major MB, Myers A, Sáez K, Henríquez JP, Zhao A, Wollmer MA, Nitsch RM, Hock C, Morris CM, Hardy J, Moon RT. · Howard Hughes Medical Institute, University of Washington School of Medicine, Seattle, WA 98195, USA. · Proc Natl Acad Sci U S A. · Pubmed #17517621 links to  free full text

Abstract: Genome-wide linkage studies have defined a broad susceptibility region for late-onset Alzheimer's disease on chromosome 12, which contains the Low-Density Lipoprotein Receptor-Related Protein 6 (LRP6) gene, a coreceptor for Wnt signaling. Here, we report the association between common LRP6 variants and late-onset Alzheimer's disease in a multicenter case-control series as well as in a large family-based series ascertained by the National Institute of Mental Health-National Institute on Aging Genetics Initiative. As shown in the genome-wide linkage studies, our association depends mainly on apolipoprotein E-epsilon4 (APOE-epsilon4) carrier status. Haplotype tagging single-nucleotide polymorphisms (SNPs) with a set of seven allelic variants of LRP6 identified a putative risk haplotype, which includes a highly conserved coding sequence SNP: Ile-1062 --> Val. Functional analyses revealed that the associated allele Val-1062, an allele previously linked to low bone mass, has decreased beta-catenin signaling in HEK293T cells. Our study unveils a genetic relationship between LRP6 and APOE and supports the hypothesis that altered Wnt/beta-catenin signaling may be involved in this neurodegenerative disease.

Wollmer MA, Sleegers K, Ingelsson M, Zekanowski C, Brouwers N, Maruszak A, Brunner F, Huynh KD, Kilander L, Brundin RM, Hedlund M, Giedraitis V, Glaser A, Engelborghs S, De Deyn PP, Kapaki E, Tsolaki M, Daniilidou M, Molyva D, Paraskevas GP, Thal DR, Barcikowska M, Kuznicki J, Lannfelt L, Van Broeckhoven C, Nitsch RM, Hock C, Papassotiropoulos A. · Division of Psychiatry Research, University of Zürich, August Forel Str. 1, 8008 Zurich, Switzerland. · Neurogenetics. · Pubmed #17387528 No free full text.

Abstract: Alzheimer's disease (AD) is a genetically complex disorder, and several genes related to cholesterol metabolism have been reported to contribute to AD risk. To identify further AD susceptibility genes, we have screened genes that map to chromosomal regions with high logarithm of the odds scores for AD in full genome scans and are related to cholesterol metabolism. In a European screening sample of 115 sporadic AD patients and 191 healthy control subjects, we analyzed single nucleotide polymorphisms in 28 cholesterol-related genes for association with AD. The genes HMGCS2, FDPS, RAFTLIN, ACAD8, NPC2, and ABCG1 were associated with AD at a significance level of P < or = 0.05 in this sample. Replication trials in five independent European samples detected associations of variants within HMGCS2, FDPS, NPC2, or ABCG1 with AD in some samples (P = 0.05 to P = 0.005). We did not identify a marker that was significantly associated with AD in the pooled sample (n = 2864). Stratification of this sample revealed an APOE-dependent association of HMGCS2 with AD (P = 0.004). We conclude that genetic variants investigated in this study may be associated with a moderate modification of the risk for AD in some samples.

Wollmer MA, Nitsch RM, Hock C, Papassotiropoulos A. · Division of Psychiatry Research, University of Zurich, Zurich, Switzerland. · Neurodegener Dis. · Pubmed #17192722 No free full text.

Abstract: BACKGROUND: Colony-stimulating factor 1 (CSF1) regulates the proliferation and differentiation of myelomonocytic cells. Microglial cells of CSF1-deficient mice are reduced in number and are functionally impaired. CSF1-deficient mice exhibit subtle neurodevelopmental defects, enhanced neuronal vulnerability. Moreover, it has been reported that these mice may have amyloid-plaque-like depositions in the brain at an early age. The human CSF1 gene maps to chromosome 1p21-p13, a region previously linked to Alzheimer's disease (AD). Thus, CSF1 is a functional and positional candidate gene for AD. OBJECTIVE: We assessed if genetic variability of CSF1 may influence the risk for AD. METHODS: We conducted a population-based case-control association study with 3 single nucleotide polymorphisms (SNPs) across the CSF1 locus in a sample of n = 185 (rs3093054, rs756325) and n = 327 (rs1058885) individuals. RESULTS: None of the 3 investigated SNPs was associated with the risk for AD in our sample. CONCLUSION: These data do not support the hypothesis that genetic variability of CSF1 influences the risk for AD.

Mondadori CR, Buchmann A, Mustovic H, Schmidt CF, Boesiger P, Nitsch RM, Hock C, Streffer J, Henke K. · Division of Psychiatry Research University of Zurich, Switzerland. · Brain. · Pubmed #17012294 links to  free full text

Abstract: Presenilin 1 (PSEN1) mutations cause autosomal dominant familial Alzheimer's disease (FAD). PSEN1 mutation carriers undergo the course of cognitive deterioration, which is typical for sporadic Alzheimer's disease but disease onset is earlier and disease progression is faster. Here, we sought to detect signs of FAD in presymptomatic carriers of the PSEN1 mutation (C410Y) by use of a neuropsychological examination, functional MRI during learning and memory tasks and MRI volumetry. We examined five non-demented members of a FAD family and 21 non-related controls. Two of the five family members were carrying the mutation; one was 20 years old and the other 45 years old. The age of clinical manifestation of FAD in the family studied here is approximately 48 years. Neuropsychological assessments suggested subtle problems with episodic memory in the 20-year-old mutation carrier. The middle-aged mutation carrier fulfilled criteria for amnestic mild cognitive impairment. The 20-year-old mutation carrier exhibited increased, while the middle-aged mutation carrier exhibited decreased brain activity compared to controls within memory-related neural networks during episodic learning and retrieval, but not during a working-memory task. The increased memory-related brain activity in the young mutation carrier might reflect a compensatory effort to overcome preclinical neural dysfunction caused by first pathological changes. The activity reductions in the middle-aged mutation carrier might reflect gross neural dysfunction in a more advanced stage of neuropathology. These data suggest that functional neuroimaging along with tasks that challenge specifically those brain areas which are initial targets of Alzheimer's disease pathology may reveal activity alterations on a single-subject level decades before the clinical manifestation of Alzheimer's disease.

Papassotiropoulos A, Lambert JC, Wavrant-De Vrièze F, Wollmer MA, von der Kammer H, Streffer JR, Maddalena A, Huynh KD, Wolleb S, Lutjohann D, Schneider B, Thal DR, Grimaldi LM, Tsolaki M, Kapaki E, Ravid R, Konietzko U, Hegi T, Pasch T, Jung H, Braak H, Amouyel P, Rogaev EI, Hardy J, Hock C, Nitsch RM. · Division of Psychiatry Research, University of Zurich, Zurich, Switzerland. papas@ · Neurodegener Dis. · Pubmed #16909003 No free full text.

Abstract: Alzheimer's disease (AD) is the most common cause of dementia. It is characterized by beta-amyloid (A beta) plaques, neurofibrillary tangles and the degeneration of specifically vulnerable brain neurons. We observed high expression of the cholesterol 25-hydroxylase (CH25H) gene in specifically vulnerable brain regions of AD patients. CH25H maps to a region within 10q23 that has been previously linked to sporadic AD. Sequencing of the 5' region of CH25H revealed three common haplotypes, CH25Hchi2, CH25Hchi3 and CH25Hchi4; CSF levels of the cholesterol precursor lathosterol were higher in carriers of the CH25Hchi4 haplotype. In 1,282 patients with AD and 1,312 healthy control subjects from five independent populations, a common variation in the vicinity of CH25H was significantly associated with the risk for sporadic AD (p = 0.006). Quantitative neuropathology of brains from elderly non-demented subjects showed brain A beta deposits in carriers of CH25Hchi4 and CH25Hchi3 haplotypes, whereas no A beta deposits were present in CH25Hchi2 carriers. Together, these results are compatible with a role of CH25Hchi4 as a putative susceptibility factor for sporadic AD; they may explain part of the linkage of chromosome 10 markers with sporadic AD, and they suggest the possibility that CH25H polymorphisms are associated with different rates of brain A beta deposition.

Maddalena AS, Papassotiropoulos A, Gonzalez-Agosti C, Signorell A, Hegi T, Pasch T, Nitsch RM, Hock C. · Division of Psychiatry Research, University of Zürich, Zürich, Switzerland. · Neurodegener Dis. · Pubmed #16908995 No free full text.

Abstract: Amyloid-beta peptides (Abeta) are major components of amyloid plaques in the Alzheimer's disease (AD) brain and have been proposed as diagnostic markers in cerebrospinal fluid (CSF). Abeta derived from brain may be processed into fragments before emerging in CSF. Therefore, we determined mass profiles of Abeta peptides in CSF of patients with AD and age-matched healthy control subjects (CTR) by using protein biochip technology. Abeta peptides were captured on the chip surfaces (spots) by the specific monoclonal antibody 6E10 and were then analyzed by integrated surface-enhanced laser desorption and ionization time-of-flight mass spectrometry (SELDI-TOF-MS). We found Abeta species with mean molecular masses at 1,583.3 Da (corresponding to Abeta2-14), 2,068.5 Da (Abeta1-17), 2,166.4 Da (Abeta1-18), 3,676.6 Da (Abeta1-33), 3,789.4 Da (Abeta1-34), 4,076.9 Da (Abeta1-37), 4,134.0 Da (Abeta1-38), 4,233.3 Da (Abeta1-39), 4,332.4 Da (Abeta1-40) and 4,516.8 Da (Abeta1-42) in both AD (n = 24) and CTR (n = 24) subjects. Abeta1-38 appeared to be a major Abeta species in human CSF along with Abeta1-40. Quantitation revealed that CSF levels of Abeta1-38 were significantly decreased in AD as compared to CTR subjects. The CSF profile of Abeta peptides may be used for diagnostic and therapeutic purposes in clinical studies.

Wollmer MA, Kapaki E, Hersberger M, Muntwyler J, Brunner F, Tsolaki M, Akatsu H, Kosaka K, Michikawa M, Molyva D, Paraskevas GP, Lütjohann D, von Eckardstein A, Hock C, Nitsch RM, Papassotiropoulos A. · Division of Psychiatry Research, University of Zürich, Switzerland. · Am J Med Genet B Neuropsychiatr Genet. · Pubmed #16752360 No free full text.

Abstract: A recent study demonstrated a significant genetic association between the ATP-binding cassette transporter A2 (ABCA2) and the risk for Alzheimer's disease (AD) in a large Caucasian sample. The rare T allele of the synonymous exonic single nucleotide polymorphism (SNP) rs908832 was overrepresented in early-onset AD patients as compared to cognitively healthy controls. Here we confirm the association of rs908832 with AD in a Western European population (n = 291, P = 0.008). In a second sample from Southern Europe, rs908832 was not associated with AD. Interestingly, rs908832 was not polymorphic in a Japanese sample. Furthermore, rs908832 was not associated with either serum cholesterol levels or with the risk for coronary artery disease, but seemed to be related to cholesterol levels in the cerebrospinal fluid. These data suggest that ABCA2 may exert population-dependent effects on the genetic risk for sporadic AD and support a role of ABC lipid transporters in the pathogenesis of this disease.

Papassotiropoulos A, Wollmer MA, Tsolaki M, Brunner F, Molyva D, Lütjohann D, Nitsch RM, Hock C. · Division of Psychiatry Research, University of Zurich, Zurich, Switzerland. · J Clin Psychiatry. · Pubmed #16013913 No free full text.

Abstract: OBJECTIVE: Polygenic diseases are related to the complex interplay of genetic variations. We evaluated whether clusters of cholesterol- and lipid-related genetic variations are associated with Alzheimer's disease. METHOD: We analyzed 12 cholesterol-related single nucleotide polymorphisms and 48 control polymorphisms in 545 study participants (Alzheimer's disease group N = 284; control group N = 261). Diagnoses of Alzheimer's disease were made according to the NINCDS-ADRDA criteria. Multi-locus genetic association analysis was done with the set-association method. Dates of data collection were from January 2000 to December 2003. RESULTS: We identified a cluster of polymorphisms in APOE, SOAT1, APOE 5'-untranslated region, OLR1, CYP46A1, LPL, LIPA, and APOA4 conferring significant (p = .0002) susceptibility for Alzheimer's disease. This gene cluster reached a diagnostic accuracy of 74% and correlated significantly (p = .018) with the levels of the brain cholesterol catabolite 24S-hydroxycholesterol in the cerebrospinal fluid. CONCLUSION: Our results establish a novel approach for the identification of disease-related genetic clusters and demonstrate the need for multi-locus methods in the genetics of complex diseases.

Papassotiropoulos A, Tsolaki M, Wollmer MA, Molyva D, Thal DR, Huynh KD, Tracy J, Staehelin HB, Monsch AU, Nitsch RM, Hock C. · Division of Psychiatry Research, University of Zürich, Lengstrasse 31, 8029 Zürich, Switzerland. · Am J Med Genet B Neuropsychiatr Genet. · Pubmed #15558716 No free full text.

Abstract: A 30 cM broad genomic region on the long arm of chromosome 10 at 80 cM shows significant and consistent linkage with AD and with plasma concentration of the beta-amyloid peptide 1-42 (Abeta42). The PLAU gene, which is involved in the production and degradation of Abeta42, maps to that region and is therefore a strong positional candidate for association with sporadic AD. We analyzed the non-synonymous single nucleotide polymorphism (SNP) rs2227564 in two independent case-control series from Switzerland and Greece and investigated the influence of this SNP on cognition in elderly individuals. Because PLAU modulates the cleavage of the amyloid precursor protein (APP) and the degradation of Abeta, we also determined the levels of Abeta in the brain, plasma and in the cerebrospinal fluid (CSF). We found no evidence for association of this SNP with AD or with AD-related traits such as beta-amyloid load in the medial temporal lobe or Abeta42 concentration in the CSF and in plasma. Our findings do not support a major role of PLAU polymorphisms as susceptibility factors for AD and suggest that large-scale association studies which combine genetic information from populations with similar genetic background might prevent the generation of spurious associations. Although PLAU may be pathophysiologially related to AD, the contribution of common genetic variants of this gene to the risk for developing AD is likely to be low.

Günther C, von Hadeln K, Müller-Thomsen T, Alberici A, Binetti G, Hock C, Nitsch RM, Stoppe G, Reiss J, Gal A, Finckh U. · Department of Human Genetics, University Hospital Hamburg-Eppendorf, Butenfeld 42, 22529 Hamburg, Germany. · Neurosci Lett. · Pubmed #15464268 No free full text.

Abstract: Mitochondrial transcription factor A (TFAM) is essential for transcription and replication of mammalian mitochondrial DNA (mtDNA). Disturbance of maintenance of mtDNA integrity or mitochondrial function may underlay neurodegenerative disorders such as Alzheimer disease (AD). TFAM, the gene encoding TFAM maps to chromosome 10q21.1, a region that showed linkage to late-onset AD in several study samples. We screened TFAM for single nucleotide polymorphisms (SNPs) and genotyped the G>C SNP rs1937, coding for S12T in mitochondrial signal sequence of TFAM, and the A>G SNP rs2306604 (IVS4+113A>G) in 372 AD patients and 295 nondemented control subjects. There was an association of genotype rs1937G/G with AD in females and an association of a TFAM haplotype with AD both in the whole sample and in females. The findings suggest that a TFAM haplotype containing rs1937 G (for S12) may be a moderate risk factor for AD.

de Quervain DJ, Poirier R, Wollmer MA, Grimaldi LM, Tsolaki M, Streffer JR, Hock C, Nitsch RM, Mohajeri MH, Papassotiropoulos A. · Division of Psychiatry Research, University of Zürich, Zürich, Switzerland. · Hum Mol Genet. · Pubmed #14583441 links to  free full text

Abstract: Because glucocorticoid excess increases neuronal vulnerability, genetic variations in the glucocorticoid system may be related to the risk for Alzheimer's disease (AD). We analyzed single-nucleotide polymorphisms in 10 glucocorticoid-related genes in a population of 814 AD patients and unrelated control subjects. Set-association analysis revealed that a rare haplotype in the 5' regulatory region of the gene encoding 11beta-hydroxysteroid dehydrogenase type 1 (HSD11B1) was associated with a 6-fold increased risk for sporadic AD. Results of a reporter-gene assay indicated that the rare risk-associated haplotype altered HSD11B1 transcription. HSD11B1 controls tissue levels of biologically active glucocorticoids and thereby influences neuronal vulnerability. Our results indicate that a functional variation in the glucocorticoid system increases the risk for AD, which may have important implications for the diagnosis and treatment of this disease.

Maddalena A, Papassotiropoulos A, Müller-Tillmanns B, Jung HH, Hegi T, Nitsch RM, Hock C. · Division of Psychiatry Research, University of Zurich, Switzerland. · Arch Neurol. · Pubmed #12975284 links to  free full text

Abstract: BACKGROUND: The antemortem diagnosis of Alzheimer disease (AD) requires time-consuming and costly procedures. Therefore, biochemical tests that can direct the physician rapidly to the correct diagnosis are highly desirable. Measurement of single biochemical markers in cerebrospinal fluid (CSF), such as total tau protein and beta-amyloid peptide42 (Abeta42), shows robust alterations that highly correlate with the clinical diagnosis of AD but generally lack sufficient diagnostic accuracy. OBJECTIVE: To study the combination of CSF phosphorylated tau protein (phospho-tau) and Abeta42 as biochemical markers for AD. METHODS: We combined CSF measurements of phospho-tau and Abeta42 in 100 consecutive patients who under-went diagnostic workup for dementia and in 31 healthy control subjects. RESULTS: We found that the calculated ratio of phospho-tau to Abeta42 was significantly increased in patients with AD and provided high diagnostic accuracy in distinguishing patients with AD from healthy control subjects (sensitivity, 86%; specificity, 97%), subjects with non-AD dementias (sensitivity, 80%; specificity, 73%), and subjects with other neurological disorders (sensitivity, 80%; specificity, 89%). CONCLUSION: The diagnostic usefulness of the CSF ratio of phospho-tau to Abeta42 is superior to either measure alone and can be recommended as an aid to evaluating individuals suspected of having dementia.