Alzheimer Disease: Wiltfang J

Weih M, Abu-Omar K, Esselmann H, Gelbrich G, Lewczuk P, Rütten A, Wiltfang J, Kornhuber J. · Psychiatrische und Psychotherapeutische Klinik, Universitätsklinikum Erlangen. · Fortschr Neurol Psychiatr. · Pubmed #19283649 No free full text.

Abstract: There is accumulating evidence from animal and epidemiologic studies that physical exercise is neuroprotective in healthy animals and humans and can prevent cognitive decline in chronic neurodegenerative processes like Alzheimer's dementia. However, data from well-designed interventional, randomized non-pharmacologic trials is lacking in contrast to other areas of medicine like prevention of hypertension, diabetes or the antipsychotic-associated metabolic syndrome. The demonstration of a potential positive effect of physical exercise on preventing dementia using a controlled study design would represent a significant progress in the prevention of dementia and public health, especially as long as other treatments for dementia prevention are lacking.

Lewczuk P, Wiltfang J. · Department of Psychiatry and Psychotherapy, Universitätsklinikum Erlangen, Erlangen, Germany. · Proteomics. · Pubmed #18271068 No free full text.

Abstract: The aim of this review is to present current state of the art on the field of routine neurochemical dementia diagnostics (NDD) with a focus on cerebrospinal fluid (CSF) biomarkers: amyloid beta peptides, tau protein, and its phosphorylated form (pTau). After several years of experience, it is reasonably to postulate that CSF biomarkers analysis is an increasingly important tool within the early and differential diagnosis of dementia syndromes. Actual research activities are briefly discussed, too, including: (i) possibilities and limitations of the diagnosis of incipient Alzheimer's disease in preclinical stages (e.g., mild cognitive impairment), (ii) the role of multiplexing technologies in dementia biomarkers research, (iii) the role of biomarkers in differential diagnosis of dementia syndromes, (iv) approaches to improve analytical performance of available methods, and (v) research activities to identify dementia biomarkers in blood.

Klafki HW, Staufenbiel M, Kornhuber J, Wiltfang J. · Department of Psychiatry and Psychotherapy, University of Erlangen-Nuremberg, Erlangen, Germany. · Brain. · Pubmed #17018549 links to  free full text

Abstract: Alzheimer's disease is an age-related progressive neurodegenerative disorder with an enormous unmet medical need. It is the most common form of dementia affecting approximately 5% of adults over 65 years. In view of our ageing society the number of patients, as well as the economical and social impact, is expected to grow dramatically in the future. Currently available medications appear to be able to produce moderate symptomatic benefits but not to stop disease progression. The search for novel therapeutic approaches targeting the presumed underlying pathogenic mechanisms has been a major focus of research and it is expected that novel medications with disease-modifying properties will emerge from these efforts in the future. In this review, currently available drugs as well as novel therapeutic strategies, in particular those targeting amyloid and tau pathologies, are discussed.

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.

Bleich S, Römer K, Wiltfang J, Kornhuber J. · Department of Psychiatry and Psychotherapy, Friedrich-Alexander University of Erlangen-Nuremberg, Germany. · Int J Geriatr Psychiatry. · Pubmed #12973748 No free full text.

Abstract: Glutamate is the most important excitatory neurotransmitter in the central nervous system. In the process, glutamate fulfills numerous physiological functions, but also plays an important role in the pathophysiology of different neurological and psychiatric diseases, especially when an imbalance in glutamatergic neurotransmission occurs. Under certain conditions, glutamate has a toxic action resulting from an activation of specific glutamate receptors, which leads to acute or chronic death of nerve cells. Such mechanisms are currently under discussion in acute neuronal death within the context of hypoxia, ischaemia and traumas, as well as in chronic neurodegenerative or neurometabolic diseases, idiopathic parkinsonian syndrome, Alzheimer's dementia and Huntington's disease. It is hoped that glutamate antagonists will lead to novel therapies for these diseases, whereby the further development of glutamate antagonists for blocking disease-specific subtypes of glutamate receptors may be of major importance in the future.

Wiltfang J, Esselmann H, Maler JM, Bleich S, Hüther G, Kornhuber J. · Department of Psychiatry, Georg August University, Göttingen, Germany. · Gerontology. · Pubmed #11287729 No free full text.

Abstract: Over the past few years, molecular biological research has considerably deepened our understanding of the pathophysiological basis of Alzheimer's dementia (AD). Although different genetic origins of the disease have been identified, all of the findings point to a common terminal sequence in familial AD. This consists of an increased production of beta-amyloid peptides from beta-amyloid precursor protein. For the cases of sporadic AD, which far outweigh the number of cases of familial AD, an impaired catabolism of the beta-amyloid peptides may also be pathophysiologically decisive according to the latest findings. Research into the molecular level of AD makes it possible to identify points of attack for rational drug treatment of the disease, while molecular markers of AD are increasingly being used as a part of early and differential neurochemical diagnostics.

Kropp S, Schlimme J, Bleich S, Wiltfang J, Dietrich DE, Emrich HM. · Klinische Psychiatrie und Psychotherapie, Medizinische Hochschule Hannover. · Fortschr Neurol Psychiatr. · Pubmed #10923250 No free full text.

Abstract: The dementia of the Alzheimer type (DAT) is a chronic neurodegenerative illness. It will continue to increase because of rising life expectancy in the industrialized countries. Apart from the physicians interest to treat, there is also an economically justified interest to reduce the disease progression in this group of patients. The main intention of the treating physicians is to keep their patients independent as long as possible. Up to now Alzheimer's disease can only be treated symptomatically. The verified diagnosis of DAT still depends on the neuropathological investigation of brain tissue. Therefore the clinical diagnosis of DAT during lifetime should be supported by chemical analysis of typical changes in the cerebrospinal fluid (CSF) at an early stage. Meanwhile, several therapeutics with proven effectiveness in clinical studies are certified for the symptomatic treatment of DAT. However, these therapeutics are still relatively expansive. Due to this fact the clinical diagnosis of DAT should be supported by clinical-chemical markers before the beginning of such a treatment. In this paper we present the diagnostic steps in dementia patients, who are examined in our departments. Patients suspicious of DAT always are asked for a spinal tap in addition to other diagnostic tools. In case of a typical clinical constellation, the exclusion of a primarily vascular dementia as well as the proof of decreased A beta 1-42 peptides and an increased tau protein in CSF we recommend the new drugs for DAT as meaningful and justified therapeutics to yield optimal treatment.

Kessler H, Pajonk FG, Bach D, Schneider-Axmann T, Falkai P, Herrmann W, Multhaup G, Wiltfang J, Schäfer S, Wirths O, Bayer TA. · Department of Psychiatry and Psychotherapy, Saarland University Hospital, Homburg/Saar, Germany. · J Neural Transm. · Pubmed #18972062 No free full text.

Abstract: A plethora of reports suggest that copper (Cu) homeostasis is disturbed in Alzheimer's disease (AD). In the present report we evaluated the efficacy of oral Cu supplementation on CSF biomarkers for AD. In a prospective, randomized, double-blind, placebo-controlled phase 2 clinical trial (12 months long) patients with mild AD received either Cu-(II)-orotate-dihydrate (verum group; 8 mg Cu daily) or placebo (placebo group). The primary outcome measures in CSF were Abeta42, Tau and Phospho-Tau. The clinical trial demonstrates that long-term oral intake of 8 mg Cu can be excluded as a risk factor for AD based on CSF biomarker analysis. Cu intake had no effect on the progression of Tau and Phospho-Tau levels in CSF. While Abeta42 levels declined by 30% in the placebo group (P = 0.001), they decreased only by 10% (P = 0.04) in the verum group. Since decreased CSF Abeta42 is a diagnostic marker for AD, this observation may indicate that Cu treatment had a positive effect on a relevant AD biomarker. Using mini-mental state examination (MMSE) and Alzheimer disease assessment scale-cognitive subscale (ADAS-cog) we have previously demonstrated that there are no Cu treatment effects on cognitive performance, however. Finally, CSF Abeta42 levels declined significantly in both groups within 12 months supporting the notion that CSF Abeta42 may be valid not only for diagnostic but also for prognostic purposes in AD.

Maler JM, Spitzer P, Lewczuk P, Kornhuber J, Herrmann M, Wiltfang J. · Department of Psychiatry and Psychotherapy, University of Erlangen-Nuremberg, Erlangen, Germany. · Mol Psychiatry. · Pubmed #17033629 No free full text.

Abstract: Hematopoietic stem cells contribute to mammalian brain tissue regeneration by transdifferentiation processes. We found decreased counts of circulating CD34+ cells in early Alzheimer's dementia (AD; P = 0.01), which significantly correlated with age (r = -0.661; P = 0.001), cerebrospinal fluid beta-amyloid (Abeta)1-42 (r = -0.467; P = 0.025) and most pronounced the Abeta42/40 ratio (r = -0.688; P = 0.005). Our data suggest a deficient regenerative hematopoietic support for the central nervous system in early AD.

Höglund K, Syversen S, Lewczuk P, Wallin A, Wiltfang J, Blennow K. · Institute of Clinical Neuroscience, Section of Experimental Neurochemistry, Göteborg University, Neurolabb, SU/Mölndal, 43180, Mölndal, Sweden. · Exp Brain Res. · Pubmed #15937702 No free full text.

Abstract: According to the amyloid cascade hypothesis, sporadic Alzheimer's disease (AD) is caused by the production and aggregation of beta-amyloid (Abeta), and the production of Abeta has recently been linked to the metabolism of cholesterol. We have previously published clinical studies where the effect of statin treatment on Abeta production has been investigated. No effect on Abeta was found, which is in disagreement with cell and animal studies. In the present study we investigated the effect of statin treatment on a disease-specific pattern consisting of a C-terminally-truncated quintet of Abeta peptides. Nineteen patients with AD were treated with simvastatin for 12 months and the quintet of Abeta peptides were analysed in cerebrospinal fluid before and after treatment. Also included was a group of 15 untreated patients with AD. We found that the Abeta peptide pattern at baseline was in agreement with earlier findings; however, we did not find any change in the Abeta peptide pattern after statin treatment. We suggest that clinical studies with extended treatment periods are performed where higher dosages of statins are used. We also believe that the pleiotropic effects of statins should be investigated further in order to elucidate the connection between Alzheimer's disease and statin treatment.

Lewczuk P, Esselmann H, Groemer TW, Bibl M, Maler JM, Steinacker P, Otto M, Kornhuber J, Wiltfang J. · Department of Psychiatry and Psychotherapy (PL, TWG, JMM, JK, JW), University of Erlangen-Nuremberg, Erlangen, Germany. · Biol Psychiatry. · Pubmed #15023581 No free full text.

Abstract: BACKGROUND: The advent of new therapeutic avenues for Alzheimer's disease (AD) calls for an improved early and differential diagnosis. METHODS: With surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS), cerebrospinal fluid from patients with AD (n = 10) and nondemented control subjects (n = 9) was studied. RESULTS: Molecular mass signals were observed corresponding to three novel amyloid beta (Abeta) peptides that have not previously been described, in addition to those previously known, with molecular masses of 4525.1 d, 4846.8 d, and 7755.8 d. The signal-to-noise ratios (S/NR) of Abeta(4525.1) and Abeta(7758.8+2H) were significantly decreased in AD [Abeta(4525.1): median 2.2 and 4.3 in AD and control subjects, respectively, p <.01; Abeta(7758.8+2H): median 1.0 and 14.0 in AD and control subjects, respectively, p <.01], whereas the S/NR of Abeta(4846.8) was significantly increased in AD (median 3.6 and 2.5 in AD and control subjects, respectively, p <.05). The S/NR of two known AD biomarkers, Abeta1-42 and Abeta1-40, expectedly turned out to be significantly decreased (p <.01) and unaltered in AD, respectively. A moderate and highly significant correlation was observed between S/NR of Abeta1-42 and Abeta42 concentration as measured with enzyme-linked immunosorbent assay (R =.67, p <.01). CONCLUSIONS: We report evidence of three novel amyloid beta peptides that might play an important role in the diagnosis and pathophysiology of Alzheimer's disease.

Rüther E, Glaser A, Bleich S, Degner D, Wiltfang J. · Department of Psychiatry, Georg-August University, Göttingen, Germany. · Pharmacopsychiatry. · Pubmed #10855461 No free full text.

Abstract: The present postmarketing surveillance (PMS) study is the first large scale systematic and prospective clinical trial of pharmacotherapeutic intervention in advanced stages of dementia. Within a validation program this study aimed at demonstrating the sensitivity of the D-Scale of change (DS-C) for measuring ADL-function. Efficacy of treatment with the NMDA-antagonist memantine was investigated in 531 patients with advanced dementia employing a parallel group design that stratified patient cohorts by severity according to GDS stages (Reisberg, 1992). Efficacy was determined on two independent levels: by the assessment of the physicians' Clinical Global Impression of Change (CGI-C) at the end of a 6-week observation period, and by the assessment of change in elementary ADL-functions by the caregivers using the D-Scale-of-Change. With the D-Scale-of-Change the caregivers can assess a change in broad functional items, i.e. cognitive and motor functions and also elementary functions of daily life. The effect size of this improvement increased constantly during the observation period. Even in patients of GDS stage 7 an improvement could be measured. These results were also seen by the physicians, who recorded an overall clinical improvement in 75.5% of the patients after 6 weeks. Tolerability evaluations resulted in the ratings "very well" by 59.5% or "well" by 35.0% of the patients. No serious adverse drug reactions occurred. A correlation analysis demonstrated a high congruency of both assessments. Furthermore, the observed time course of these improvements paralleled with the time course of symptomatic benefit by effects of memantine that had been repeatedly demonstrated in randomised, double-blind, placebo-controlled studies in mild to moderate dementia. Together with the evaluation of the scale-properties of the D-Scale for assessment of severity the D-Scale and the D-Scale-of-Change can be regarded as validated.

Jessen F, Gür O, Block W, Ende G, Frölich L, Hammen T, Wiltfang J, Kucinski T, Jahn H, Heun R, Maier W, Kölsch H, Kornhuber J, Träber F. · Department of Psychiatry, University of Bonn, Germany. · Neurology. · Pubmed #19451528 No free full text.

Abstract: OBJECTIVE: The need for biological markers of Alzheimer disease (AD) is constantly increasing. Proton magnetic resonance spectroscopy ((1)H-MRS) studies have provided consistent evidence for a reduction of the neuronal marker N-acetylaspartate (NAA) in patients with AD. Within the German Competence Network on Dementia, we conducted a (1)H-MRS study in patients with mild dementia and mild cognitive impairment (MCI) at four sites to investigate the multicenter feasibility of (1)H-MRS. METHODS: In total, 130 patients with dementia (98 AD, 32 non-AD), 136 subjects with MCI (70 of AD type, 66 of non-AD type), and 45 unimpaired control subjects were included. Single-volume (1)H-MRS of the left medial temporal lobe was performed at long and short echo times. Metabolites were quantified and metabolic ratios were determined. RESULTS: We found a significant reduction of NAA concentration in patients with AD as compared to healthy volunteers and compared to patients with MCI of AD type. NAA/Cr (creatine/phosphocreatine) was also lower in patients with AD compared to control subjects. NAA, choline compounds, and Cr were lower in patients with AD compared to patients with non-AD dementia. CONCLUSIONS: We demonstrated the multicenter feasibility of proton magnetic resonance spectroscopy ((1)H-MRS) of the medial temporal lobe in mild dementia and mild cognitive impairment, which is a prerequisite for the application of (1)H-MRS in large-scale clinical trials. Since the concentration measures of the metabolites are adjusted for brain tissue volume, these findings are indicators of biochemical pathology beyond brain atrophy.

Verwey NA, van der Flier WM, Blennow K, Clark C, Sokolow S, De Deyn PP, Galasko D, Hampel H, Hartmann T, Kapaki E, Lannfelt L, Mehta PD, Parnetti L, Petzold A, Pirttila T, Saleh L, Skinningsrud A, Swieten JC, Verbeek MM, Wiltfang J, Younkin S, Scheltens P, Blankenstein MA. · Department of Clinical Chemistry, VU University Medical Center, , HV, The Netherlands. · Ann Clin Biochem. · Pubmed #19342441 No free full text.

Abstract: BACKGROUND: Different cerebrospinal fluid (CSF) amyloid-beta 1-42 (Abeta(1-42)), total Tau (Tau) and Tau phosphorylated at threonine 181 (P-Tau) levels are reported, but currently there is a lack of quality control programmes. The aim of this study was to compare the measurements of these CSF biomarkers, between and within centres. METHODS: Three CSF-pool samples were distributed to 13 laboratories in 2004 and the same samples were again distributed to 18 laboratories in 2008. In 2004 six laboratories measured Abeta(1-42), Tau and P-Tau and seven laboratories measured one or two of these marker(s) by enzyme-linked immunosorbent assays (ELISAs). In 2008, 12 laboratories measured all three markers, three laboratories measured one or two marker(s) by ELISAs and three laboratories measured the markers by Luminex. RESULTS: In 2004, the ELISA intercentre coefficients of variance (interCV) were 31%, 21% and 13% for Abeta(1-42), Tau and P-Tau, respectively. These were 37%, 16% and 15%, respectively, in 2008. When we restricted the analysis to the Innotest (N = 13) for Abeta(1-42), lower interCV were calculated (22%). The centres that participated in both years (N = 9) showed interCVs of 21%, 15% and 9% and intra-centre coefficients (intraCV) of variance of 25%,18% and 7% in 2008. CONCLUSIONS: The highest variability was found for Abeta(1-42). The variabilities for Tau and P-Tau were lower in both years. The centres that participated in both years showed a high intraCV comparable to their interCV, indicating that there is not only a high variation between but also within centres. Besides a uniform standardization of (pre)analytical procedures, the same assay should be used to decrease the inter/intracentre variation.

Serneels L, Van Biervliet J, Craessaerts K, Dejaegere T, Horré K, Van Houtvin T, Esselmann H, Paul S, Schäfer MK, Berezovska O, Hyman BT, Sprangers B, Sciot R, Moons L, Jucker M, Yang Z, May PC, Karran E, Wiltfang J, D'Hooge R, De Strooper B. · Department for Molecular and Developmental Genetics, VIB, KULeuven, Herestraat 49, 3000 Leuven, Belgium. · Science. · Pubmed #19299585 No free full text.

Abstract: The gamma-secretase complex plays a role in Alzheimer's disease and cancer progression. The development of clinically useful inhibitors, however, is complicated by the role of the gamma-secretase complex in regulated intramembrane proteolysis of Notch and other essential proteins. Different gamma-secretase complexes containing different Presenilin or Aph1 protein subunits are present in various tissues. Here we show that these complexes have heterogeneous biochemical and physiological properties. Specific inactivation of the Aph1B gamma-secretase in a mouse Alzheimer's disease model led to improvements of Alzheimer's disease-relevant phenotypic features without any Notch-related side effects. The Aph1B complex contributes to total gamma-secretase activity in the human brain, and thus specific targeting of Aph1B-containing gamma-secretase complexes may help generate less toxic therapies for Alzheimer's disease.

Welge V, Fiege O, Lewczuk P, Mollenhauer B, Esselmann H, Klafki HW, Wolf S, Trenkwalder C, Otto M, Kornhuber J, Wiltfang J, Bibl M. · Klinik für Psychiatrie und Psychotherapie, Universität Duisburg-Essen, Rheinische Kliniken Essen, Essen, Germany. · J Neural Transm. · Pubmed #19142572 No free full text.

Abstract: Cerebrospinal fluid (CSF) concentrations of amyloid-beta (Abeta) 1-38, 1-40, 1-42, total-tau and phospho-tau in samples from 156 patients with Alzheimer's disease (AD) (n = 44), depressive cognitive complainers (DCC, n = 25) and various other forms of non-Alzheimer dementias (NAD, n = 87) were analyzed by electrochemiluminescence and enzyme linked immunosorbent assay, respectively. A significant decrease of CSF Abeta1-42 was the most powerful single marker for differentiation of AD from DCC, yielding accuracies of beyond 85%. Increased p-tau and the ratio Abeta1-42/Abeta1-38 yielded accuracies of beyond 80 and 85%, respectively, to discriminate AD versus NAD. Combining p-tau with Abeta1-42/Abeta1-38 resulted in a sensitivity of 94% for detection of AD and 85% specificity for excluding NAD. Decreased CSF Abeta1-42 represents a core biomarker for AD. The lack of specificity for exclusion of NAD can be most effectively compensated by the ratio Abeta1-42/Abeta1-38. The ratio Abeta1-42/Abeta1-38/p-tau powerfully discriminates AD versus NAD and fulfils the accuracy requirements for an applicable screening and differential diagnostic AD biomarker.

Bibl M, Wiltfang J. · Klinik für Psychiatrie und Psychotherapie, Rheinische Kliniken, Universität Duisburg-Essen, Virchowstrasse 174, 45147, Essen. · Nervenarzt. · Pubmed #18931988 No free full text.

Abstract: Over the past 10 years, the status of laboratory analysis in dementia has increasingly changed from its use for exclusion diagnoses for secondary causes of dementias to determining positive diagnoses of neurodegenerative dementias. This especially applies to the cerebrospinal fluid diagnosis of Alzheimer's disease (AD). Just a few years ago, a lumbar puncture was advised only with sufficiently founded clinical suspicion and with higher priority for the exclusion of inflammatory causes of cognitive dementias. In contrast, pathologically changed biomarkers in the cerebrospinal fluid have already been indexed as supportive attributes of the diagnosis in the 2007 amended research criteria of AD. The lumbar puncture is therefore increasingly becoming part of the clinical routine diagnosis of demential processes and has, to some extent, far-reaching consequences. In this article, we discuss some of the important aspects.

Maler JM, Spitzer P, Klafki HW, Esselmann H, Lewczuk P, Kornhuber J, Herrmann M, Wiltfang J. · Department of Psychiatry and Psychotherapy, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany. · J Neuroimmunol. · Pubmed #18824266 No free full text.

Abstract: The presence of cells of the mononuclear phagocyte lineage surrounding neuritic and vascular beta-amyloid (Abeta) plaques is a hallmark of Alzheimer's disease (AD) neuropathology. The fractional Abeta peptide patterns released by human mononuclear phagocyte (MNP), lymphocyte and PBMC cultures were assessed by Abeta-SDS-PAGE/immunoblot and compared with the Abeta patterns in neuronal supernatants, in cerebrospinal fluid (CSF), and plasma. MNP released substantial amounts of Abeta peptides and the Abeta pattern contrasted with that in neuronal supernatants, CSF and plasma by reduced Abeta(1-42) and increased proportions of N-truncated Abeta species. MNP derived from early AD patients released significantly more total Abeta peptides than age-matched controls. The proportion of Abeta(1-42) was not altered.

Brechlin P, Jahn O, Steinacker P, Cepek L, Kratzin H, Lehnert S, Jesse S, Mollenhauer B, Kretzschmar HA, Wiltfang J, Otto M. · Department of Neurodegeneration and Restorative Research, Center of Neurological Medicine, University of Goettingen, Goettingen, Germany. · Proteomics. · Pubmed #18814332 No free full text.

Abstract: So far only the detection of 14-3-3 proteins in cerebrospinal fluid (CSF) is included in the diagnostic criteria for sporadic Creutzfeldt-Jakob disease (sCJD). However, this assay cannot be used for screening because of the high rate of false positive results in sCJD, and often negative results in variant CJD. To facilitate the differential diagnosis of CJD, we applied 2-D differential gel-electrophoresis (2-D DIGE) as a quantitative proteomic screening system for CSF proteins. We compared 36 patients suffering from sCJD with 30 patients suffering from other neurodegenerative diseases. Sample preparation was optimized in consideration of the fact that CSF is composed of blood- and brain-derived proteins, and an improved 2-D DIGE protocol was established. Using this method in combination with protein identification by MALDI-TOF-MS, several known surrogate markers of sCJD like 14-3-3 protein, neuron-specific enolase, and lactate dehydrogenase were readily identified. Moreover, a not yet identified protein with an approximate molecular mass of 85 kDa was found as marker for sCJD with high diagnostic specificity and sensitivity. We conclude that our proteomic approach is useful to differentiate CJD from other neurodegenerative diseases and expect that CSF-optimized 2-D DIGE will find broad application in the search for other brain derived proteins in CSF.

Mamo JC, Jian L, James AP, Flicker L, Esselmann H, Wiltfang J. · Division of Health Sciences, Curtin University of Technology and ATN Centre for Metabolic Health and Fitness. · Ann Clin Biochem. · Pubmed #18583625 No free full text.

Abstract: BACKGROUND: Plasma amyloid beta-peptide (Abeta) can compromise the blood-brain barrier, contributing to cerebrovascular alterations and amyloid angiopathy in Alzheimer's disease (AD). The objectives of this study were to investigate the distribution of lipoprotein-bound plasma-Abeta isoforms. METHODS: This involved a case-control study of subjects with AD or amnestic mild cognitive impairment (MCI) versus controls. Lipoprotein Abeta distribution was determined in fasted plasma. For assessment of chylomicron homeostasis in the postabsorptive state, subjects were bled 4 h after a low-fat meal. The main outcome measures were plasma lipoprotein Abeta isoform distribution and lipid homeostasis. RESULTS: We found the majority of plasma Abeta to be associated with triglyceride-rich lipoproteins (TRLs) encompassing chylomicrons, VLDL and IDL. For all lipoprotein groups, Abeta1-40 was the predominant isoform, accounting for approximately 50% of the total. Thereafter, equivalent amounts of the isoforms 1-42, 2-40, 1-38, 1-37 and 1-39 were found. Abeta1-37, Abeta1-38 and Abeta2-40 isoforms were significantly enriched within the TRL fraction of AD/MCI subjects and similar trends were observed for isoforms Abeta1-39, Abeta1-40 and Abeta1-42. Lipoprotein-Abeta was inversely associated with plasma total- and LDL cholesterol. AD/MCI subjects were not dyslipidaemic, however, there was evidence of accumulation of chylomicrons in the postabsorptive state. CONCLUSIONS: Our data show that Abeta was found to be associated with plasma lipoproteins, especially those enriched with triglyceride. We find that Abeta may be increased in normolipidaemic AD subjects, commensurate with possible disturbances in postprandial lipoprotein homeostasis.

Kölsch H, Jessen F, Wiltfang J, Lewczuk P, Dichgans M, Kornhuber J, Frölich L, Heuser I, Peters O, Schulz JB, Schwab SG, Maier W. · Department of Psychiatry, University of Bonn, Bonn, Germany. · Neurosci Lett. · Pubmed #18541377 No free full text.

Abstract: SORL1 gene variants were described as risk factors of Alzheimer's disease (AD). We investigated the association of four SORL1 variants with CSF levels of Abeta42 and Abeta40 in 153 AD patients recruited from a multicenter study of the German Competence Net Dementias. Only one SORL1 SNP was associated with altered Abeta42 levels in the single marker analysis (SNP21: p=0.011), the other SNPs did not show an association with Abeta42 or Abeta40 CSF levels. Haplotype analysis identified a three marker SORL1 haplotype consisting of SNP19 T-allele, SNP21 G-allele and SNP23 A-allele (T/G/A) which was associated with reduced Abeta42 CSF levels in AD patients (p=0.003). Abeta40 levels were also lower in carriers of this haplotype; however, this did not reach statistical significance (p=0.15). We found a SORL1 haplotype which was associated with CSF levels of amyloid-beta cleavage products, measured as altered levels of Abeta42. Thus our data suggest that SORL1 gene variants might influence AD pathology.

Maler JM, Spitzer P, Klafki HW, Esselmann H, Bibl M, Lewczuk P, Kornhuber J, Herrmann M, Wiltfang J. · Department of Psychiatry and Psychotherapy, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany. · Brain Behav Immun. · Pubmed #18511234 No free full text.

Abstract: Cells of the mononuclear phagocyte system are closely associated with vascular and neuritic beta-amyloid deposits in Alzheimer's disease. Using one-dimensional and newly developed two-dimensional Abeta-SDS-PAGE Western immunoblot techniques (1D/2D-Abeta-WIB) we investigated the patterns of Abeta peptides released by primary non-adherent and adherence-activated human mononuclear phagocytes in vitro. An overall increase of total released Abeta peptides (Abeta(total)) was observed in adherence-activated mononuclear phagocyte cultures. 2D-Abeta-WIB revealed that the proportion of Abeta(1-40) decreased significantly to 50.2+/-5.4% (n=10) of Abeta(total) compared to 65.9+/-5.6% (n=7) in non-adherent cultures (p<0.0001, t=5.82). Abeta(1-42) accounted for only 3.0+/-2.1% of Abeta(total) and its proportion did not change significantly upon adherence (2.8+/-0.5% of Abeta(total)). In adherence-activated cultures we detected pronounced shifts in the fractional pattern of released Abeta peptides in favour of N-truncated species. The second most prominent Abeta peptide accounted for as much as 12.7+/-3.0% of Abeta(total) (2.0+/-1.2% in non-adherent cultures; p<0.0001, t=9.00) and was identified as Abeta(2-40) by comigration with a synthetic peptide and by N-terminal-specific antibodies. A strong increase of a further Abeta immunoreactive spot migrating at pI 5.45 was observed. It accounted for 9.2+/-1.7% of Abeta(total) as compared to 1.0+/-0.9% in non-adherent cultures (p<0.0001, t=11.61) and presumably represented a variant of Abeta(2-40) as determined by C-terminal Abeta(40)-specific immunoprecipitation and N-terminal-specific immunodetection. Thus, mononuclear phagocytes might be one source of the N-truncated Abeta peptides regularly found in human plasma and are less likely to contribute substantially to plasma Abeta(1-42).

Czirr E, Cottrell BA, Leuchtenberger S, Kukar T, Ladd TB, Esselmann H, Paul S, Schubenel R, Torpey JW, Pietrzik CU, Golde TE, Wiltfang J, Baumann K, Koo EH, Weggen S. · Molecular Neuropathology Group, Department of Neuropathology, Heinrich Heine-University, D-40225 Duesseldorf, Germany. · J Biol Chem. · Pubmed #18426795 links to  free full text

Abstract: Proteolytic processing of the amyloid precursor protein by beta- and gamma-secretase generates the amyloid-beta (Abeta) peptides, which are principal drug targets in Alzheimer disease therapeutics. gamma-Secretase has imprecise cleavage specificity and generates the most abundant Abeta40 and Abeta42 species together with longer and shorter peptides such as Abeta38. Several mechanisms could explain the production of multiple Abeta peptides by gamma-secretase, including sequential processing of longer into shorter Abeta peptides. A novel class of gamma-secretase modulators (GSMs) that includes some non-steroidal anti-inflammatory drugs has been shown to selectively lower Abeta42 levels without a change in Abeta40 levels. A signature of GSMs is the concomitant increase in shorter Abeta peptides, such as Abeta38, leading to the suggestion that generation of Abeta42 and Abeta38 peptide species by gamma-secretase is coordinately regulated. However, no evidence for or against such a precursor-product relationship has been provided. We have previously shown that stable overexpression of aggressive presenilin-1 (PS1) mutations associated with early-onset familial Alzheimer disease attenuated the cellular response to GSMs, resulting in greatly diminished Abeta42 reductions as compared with wild type PS1. We have now used this model system to investigate whether Abeta38 production would be similarly affected indicating coupled generation of Abeta42 and Abeta38 peptides. Surprisingly, treatment with the GSM sulindac sulfide increased Abeta38 production to similar levels in four different PS1 mutant cell lines as compared with wild type PS1 cells. This was confirmed with the structurally divergent GSMs ibuprofen and indomethacin. Mass spectrometry analysis and high resolution urea gel electrophoresis further demonstrated that sulindac sulfide did not induce detectable compensatory changes in levels of other Abeta peptide species. These data provide evidence that Abeta42 and Abeta38 species can be independently generated by gamma-secretase and argue against a precursor-product relationship between these peptides.

Höglund K, Hansson O, Buchhave P, Zetterberg H, Lewczuk P, Londos E, Blennow K, Minthon L, Wiltfang J. · Neurochemistry Lab, Department of Neuroscience and Physiology, Göteborg University, Molndal, Sweden. · Neurodegener Dis. · Pubmed #18309230 No free full text.

Abstract: BACKGROUND: Identifying individuals at high risk of developing Alzheimer's disease (AD) is important for future therapeutic strategies, and there is a clinical need for diagnostic biomarkers to identify incipient AD. OBJECTIVE: The aim of the present study was to investigate if the AD-associated Abeta peptide pattern recently found in cerebrospinal fluid (CSF) could discriminate between patients with incipient AD and those with stable mild cognitive impairment (MCI) by analyzing CSF from patients with MCI at baseline. METHODS: The levels of Abeta(1-37, -38, -39, -40, -42) were analyzed by Abeta-SDS-PAGE/immunoblot in CSF from 19 healthy controls, 25 patients with stable MCI and from 25 patients with MCI who later developed AD during 4- to 6-year follow-up. RESULTS: All healthy controls and 20 out of 22 patients who developed AD were correctly classified by their baseline Abeta peptide pattern. In 9 out of 25 stable MCI patients, the pattern indicated incipient AD in spite of clinical nonconversion. Interestingly, these individuals had apolipoprotein E genotypes and CSF levels of tau and phospho-tau that are known to be associated with high risk of AD. CONCLUSION: Altogether, our study reveals the novel finding that the Abeta peptide pattern is able to predict AD in patients with MCI with a sensitivity of 91% and specificity of 64%. The specificity would increase to 94% if the high-risk patients in the stable MCI cohort developed AD during extended follow-up.

Maler JM, Klafki HW, Paul S, Spitzer P, Groemer TW, Henkel AW, Esselmann H, Lewczuk P, Kornhuber J, Wiltfang J. · Department of Psychiatry and Psychotherapy, University of Erlangen-Nuremberg, Erlangen, Germany. · Proteomics. · Pubmed #17924594 No free full text.

Abstract: The detailed analysis of beta-amyloid (Abeta) peptides in human plasma is still hampered by the limited sensitivity of available mass spectrometric methods and the lack of appropiate ELISAs to measure Abeta peptides other than Abeta(1-38), Abeta(1-40), and Abeta(1-42). By combining high-yield Abeta immuno- precipitation (IP), IEF, and urea-based Abeta-SDS-PAGE-immunoblot, at least 30 Abeta-immuno-reactive spots were detected in human plasma samples as small as 1.6 mL. This approach clearly resolved Abeta peptides Abeta(1-40), Abeta(1-42), Abeta(1-37), Abeta(1-38), Abeta(1-39), the N-truncated Abeta(2-40), Abeta(2-42), and, for the first time, also Abeta(1-41). Relative quantification indicated that Abeta(1-40) and Abeta(1-42) accounted for less than 60% of the total amount of Abeta peptides in plasma. All other Abeta peptides appear to be either C-terminally or N-terminally truncated forms or as yet uncharacterized Abeta species which migrated as trains of spots with distinct pIs. The Abeta pattern found in cerebrospinal fluid (CSF) was substantially less complex. This sensitive method (2-D Abeta-WIB) might help clarifying the origin of distinct Abeta species from different tissues, cell types, or intracellular pools as well as their amyloidogenicity. It might further help identifying plasma Abeta species suitable as biomarkers for the diagnosis of Alzheimer's disease (AD).