Detection and quantification of Aβ−3–40 (APP669‐711) in cerebrospinal fluid

Neurochemical biomarkers can support the diagnosis of Alzheimer’s disease and may facilitate clinical trials. In blood plasma, the ratio of the amyloid-β (Aβ) peptides Aβ−3– 40/Aβ1–42 can predict cerebral amyloid-β pathology with high accuracy (Nakamura et al., 2018). Whether or not Aβ−3–40 (aka. amyloid precursor protein (APP) 669– 711) is also present in cerebrospinal fluid (CSF) is not clear. Here, we investigated whether Aβ−3–40 can be detected in CSF and to what extent the CSF Aβ−3–40/Aβ42 ratio is able to differentiate between individuals with or without amyloid-β positron emission tomography (PET) evidence of brain amyloid. The occurrence of Aβ−3–40 in human CSF was assessed by immunoprecipitation followed by mass spectrometry. For quantifying the CSF concentrations of Aβ−3–40 in 23 amyloid PET- negative and 17 amyloid PET- positive subjects, we applied a sandwich-type immunoassay. Our findings provide clear evidence of the presence of Aβ−3–40 and Aβ−3–38 in human CSF. While there was no statistically significant difference in the CSF concentration of Aβ−3–40 between the two diagnostic groups, the CSF Aβ−3–40/Aβ42 ratio was increased in the amyloid PET- positive individuals. We conclude that Aβ−3– 40 appears to be a regular constituent of CSF and may potentially serve to accentuate the selec- tive decrease in CSF Aβ42 in Alzheimer's disease

Comparison of Pharmacological Modulation of APP Metabolism in Primary Chicken Telencephalic Neurons and in a Human Neuroglioma Cell Line

Sequential cleavage of amyloid precursor protein (APP) by β- and γ-secretases and the formation of Aβ peptides are pivotal for Alzheimer's disease. Therefore, a large number of drugs has been developed targeting APP metabolism. However, many pharmacological compounds have been identified in vitro in immortalized APP overexpressing cell lines rather than in primary neurons. Here, we compared the effect of already characterized secretase inhibitors and modulators on Aβ formation in primary chicken telencephalic neurons and in a human neuroglioma cell line (H4) ectopically expressing human APP with the Swedish double mutation. Primary chicken neurons replicated the effects of a β-secretase inhibitor (β-secretase inhibitor IV), two γ-secretase inhibitors (DAPM, DAPT), two non-steroidal-anti-inflammatory drugs (sulindac sulfide, CW), and of the calpain inhibitor calpeptin. With the exception of the two γ-secretase inhibitors, all tested compounds were more efficacious in primary chicken telencephalic neurons than in the immortalized H4 cell line. Moreover, H4 cells failed to reproduce the effect of calpeptin. Hence, primary chicken telencephalic neurons represent a suitable cell culture model for testing drugs interfering with APP processing and are overall more sensitive to pharmacological interference than immortalized H4 cells ectopically expressing mutant human APP

Characterization of Contaminants from a Sanitized Milk Processing Plant

Milk processing lines offer a wide variety of microenvironments where a diversity of microorganisms can proliferate. We sampled crevices and junctions where, due to deficient reach by typical sanitizing procedures, bacteria can survive and establish biofilms. The sampling sites were the holding cell, cold storage tank, pasteurizer and storage tank - transfer pump junction. The culturable bacteria that were isolated after the sanitation procedure were predominantly Pseudomonas spp., Serratia spp, Staphylococcus sciuri and Stenotrophomonas maltophilia. We assayed several phenotypic characteristics such as the ability to secrete enzymes and siderophores, as well as the capacity of the strains to form biofilms that might contribute to their survival in a mixed species environment. The Pseudomonas spp. isolates were found to either produce proteases or lecithinases at high levels. Interestingly, protease production showed an inverse correlation with siderophore production. Furthermore, all of the Serratia spp. isolates were strong biofilm formers and spoilage enzymes producers. The organisms identified were not mere contaminants, but also producers of proteins with the potential to lower the quality and shelf-life of milk. In addition, we found that a considerable number of the Serratia and Pseudomonas spp. isolated from the pasteurizer were capable of secreting compounds with antimicrobial properties

Clinical reporting following the quantification of cerebrospinal fluid biomarkers in Alzheimer's disease: An international overview

Introduction: The current practice of quantifying cerebrospinal fluid (CSF) biomarkers as an aid in the diagnosis of Alzheimer's disease (AD) varies from center to center. For a same biochemical profile, interpretation and reporting of results may differ, which can lead to misunderstandings and raises questions about the commutability of tests. Methods: We obtained a description of (pre-)analytical protocols and sample reports from 40 centers worldwide. A consensus approach allowed us to propose harmonized comments corresponding to the different CSF biomarker profiles observed in patients. Results: The (pre-)analytical procedures were similar between centers. There was considerable heterogeneity in cutoff definitions and report comments. We therefore identified and selected by consensus the most accurate and informative comments regarding the interpretation of CSF biomarkers in the context of AD diagnosis. Discussion: This is the first time that harmonized reports are proposed across worldwide specialized laboratories involved in the biochemical diagnosis of AD

Plasma lipoprotein b-amyloid in subjects with Alzheimer's disease or mild cognitive impairment

Background: Plasma amyloid -peptide (A) 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-A isoforms.Methods: This involved a case-control study of subjects with AD or amnestic mild cognitive impairment (MCI) versus controls. Lipoprotein A 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 A isoform distribution and lipid homeostasis.Results: We found the majority of plasma A to be associated with triglyceride-rich lipoproteins (TRLs) encompassing chylomicrons, VLDL and IDL. For all lipoprotein groups, A1 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. A1 37, A1 38 and A2 40 isoforms were significantly enriched within the TRL fraction of AD/MCI subjects and similar trends were observed for isoforms A1 39, A1 40 and A1 42. Lipoprotein-A 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 A was found to be associated with plasma lipoproteins, especially those enriched with triglyceride. We find that A may be increased in normolipidaemic AD subjects, commensurate with possible disturbances in postprandial lipoprotein homeostasis

Hypocretin in cerebrospinal fluid is positively correlated with Tau and pTau

It has been suggested that sleep wake regulation as well as hypocretins play a role in the pathophysiology of Alzheimer's disease. We analyzed A beta(40), A beta(42), Tau protein, phosphorylated Tau (pTau) protein as well as hypocretin-1 concentrations in the CSF of a detection sample of 10 patients with Alzheimer's disease (AD) as well as 10 age- and gender-matched patients with major depression as a comparison group of different pathology. In order to replicate the findings, we used a confirmation sample of 17 AD patients and 8 patients with major depression. We found hypocretin-1 concentrations in CSF not to differ between patients with depression and AD. However, hypocretin-1 was significantly related to Tau (r = 0.463, p < 0.001) and pTau (r = 0.630, p < 0.0001). These effects were more pronounced in depressed patients when compared to AD patients. We conclude that hypocretin-1 may play a role in the metabolism of Tau proteins across different diagnostic entities including AD. It has to be determined whether there is a causal relationship between hypocretin-1 and Tau as well as pTau. (C) 2013 Elsevier Ireland Ltd. All rights reserved

Guideline-adherent inpatient psychiatric psychotherapeutic treatment of behavioral and psychological symptoms of dementia. Normative definition of personnel requirements

Dementia is of increasing medical and societal relevance. Hospitalization of dementia patients is mostly due to behavioral and psychological symptoms of dementia (BPSD). There is a need for sufficient qualified personnel in hospitals in order to be able to effectively treat these symptoms. This study aims at identifying the personnel requirements for guideline-conform, evidence-based inpatient treatment concepts for patients with BPSD and to compare these with the resources defined by the German psychiatric personnel regulations (Psych-PV). Furthermore, it was the aim to identify how often patients with dementia received non-pharmacological therapy during inpatient treatment. Based on the current scientific evidence for treatment of BPSD, a schedule for a multimodal non-pharmacological treatment was defined and based on this the corresponding personnel requirements were calculated. Using the treatment indicators in psychiatry and psychosomatics (VIPP) database as a reference, it was calculated on what proportion of treatment days patients were classified into G1 according to the German Psych-PV and at least once received more than two treatment units per week. For the implementation of a guideline-oriented and evidence-based treatment plan, a higher need for personnel resources than that provided by the Psych-PV was detected in all areas. Currently patients with dementia who received at least more than two treatment units per week during inpatient hospitalization, were classified into G1 according to German Psych-PV on 17.9 % of treatment days. Despite evidence for the efficacy of non-pharmacological treatment measures on BPSD, these forms of treatment cannot be sufficiently provided under the current conditions. The realization of a new quality controlled therapeutic concept is necessary to enable optimized treatment of patients with BPSD