A Specific Enzyme-Linked Immunosorbent Assay for Measuring β-Amyloid Protein Oligomers in Human Plasma and Brain Tissue of Patients With Alzheimer Disease

Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, HIM 616, 77 Ave Louis Pasteur, Boston, MA 02115, USA.
Archives of neurology (Impact Factor: 7.42). 03/2009; 66(2):190-9. DOI: 10.1001/archneurol.2008.565
Source: PubMed

ABSTRACT To examine in vivo levels of beta-amyloid (Abeta) oligomers (oAbeta) vs monomeric Abeta in plasma and brain tissue of patients with sporadic and familial Alzheimer disease (AD) using a new enzyme-linked immunosorbent assay (ELISA) specific for oAbeta.
To establish the oAbeta ELISA, the same N-terminal Abeta antibody was used for antigen capture and detection. Plasma and postmortem brain tissue from patients with AD and control subjects were systematically analyzed by conventional monomeric Abeta and new oAbeta ELISAs.
We measured oAbeta species in plasma samples from 36 patients with clinically well-characterized AD and 10 control subjects. In addition, postmortem samples were obtained from brain autopsies of 9 patients with verified AD and 7 control subjects.
Oligomeric Abeta and 4 monomeric Abeta species in plasma samples from patients with AD and control subjects were measured by ELISA.
The specificity of the oAbeta ELISA was validated with a disulfide-crossed-linked, synthetic Abeta(1-40)Ser26Cys dimer that was specifically detected before but not after the dissociation of the dimers in beta-mercaptoethanol. Plasma assays showed that relative oAbeta levels were closely associated with relative Abeta(42) monomer levels across all of the subjects. Analysis of sequential plasma samples from a subset of the patients with AD, including a patient with AD caused by a presenilin mutation, revealed decreases in both oAbeta and Abeta(42) monomer levels over a 1- to 2-year period. In brain tissue from 9 patients with AD and 7 control subjects, both oAbeta and monomeric Abeta(42) levels were consistently higher in the AD cases.
An oAbeta-specific ELISA reveals a tight link between oAbeta and Abeta(42) monomer levels in plasma and brain. Both forms can decline over time in plasma, presumably reflecting their increasing insolubility in the brain.

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Available from: Dominic M Walsh, Jun 12, 2014
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    • "This was carried out using Amyloid Beta (Aβ) ELISA Kit (Millipore catalog number EZHS42 (24). "
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    ABSTRACT: The presence of non-progressive cognitive impairment is recognized as a common feature in a substantial proportion of patients with Duchenne muscular dystrophy (DMD). Concurrently, the amyloid beta peptide (Aβ42) protein has been associated with changes in memory and cognitive functions. Also, it has been shown that different subtypes of neural stem/progenitor cells (CD 34, CD 45, nestin) are involved in the innate repair of plasticity mechanisms by the injured brain, in which Nerve Growth Factor (NGF) acts as chemotactic agents to recruit such cells. Accordingly, the present study investigated levels of CD 34, CD 45, nestin and NGF in an attempt to investigate makers of neural regeneration in DMD. Neural damage was assayed in terms of Aβ42. Results showed that Aβ42 (21.9 ± 6.7 vs. 12.13 ± 4.5) was significantly increased among DMD patients compared to controls. NGF (165.8 ± 72 vs. 89.8 ± 35.9) and mononuclear cells expressing nestin (18.9 ± 6 vs. 9 ± 4), CD 45 (64 ± 5.4 vs. 53.3 ± 5.2) and CD34 (75 ± 6.2 vs. 60 ± 4.8) were significantly increased among DMD patients compared to controls. In conclusion cognitive function decline in DMD patients is associated with increased levels of Aβ42, which is suggested to be the cause of brain damage in such patients. The significant increase plasma NFG and in the number of mononuclear cells bearing CD34, CD45 and nestin indicates that regeneration is an ongoing process in these patients. However, this regeneration cannot counterbalance the damage induced by dystrophine mutation and increased Aβ42.
    Acta myologica: myopathies and cardiomyopathies: official journal of the Mediterranean Society of Myology / edited by the Gaetano Conte Academy for the study of striated muscle diseases 05/2014; 33(1):13-18.
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    • "Instead, those studies showed that cognitive deficits were highly correlated with synapse loss [30] [31] [32], and suggested that an as-yet-unidentified toxin, but not amyloid plaques, was responsible for triggering memory loss in AD. Identification of soluble amyloid-b oligomers (AbOs) as synaptotoxins that accumulate in AD brains [33] [34] [35] [36] stimulated a paradigm shift in the field, with AbOs now considered the proximal toxins responsible for synapse dysfunction and memory failure in AD (for recent reviews, see [1,37–39]). In the following sections, we review recent findings linking the neurotoxic impact of AbOs and defects in brain insulin signaling in AD. "
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    ABSTRACT: Compelling preclinical and clinical evidence supports a pathophysiological connection between Alzheimer's disease (AD) and diabetes. Altered metabolism, inflammation, and insulin resistance are key pathological features of both diseases. For many years, it was generally considered that the brain was insensitive to insulin, but it is now accepted that this hormone has central neuromodulatory functions, including roles in learning and memory, that are impaired in AD. However, until recently, the molecular mechanisms accounting for brain insulin resistance in AD have remained elusive. Here, we review recent evidence that sheds light on how brain insulin dysfunction is initiated at a molecular level and why abnormal insulin signaling culminates in synaptic failure and memory decline. We also discuss the cellular basis underlying the beneficial effects of stimulation of brain insulin signaling on cognition. Discoveries summarized here provide pathophysiological background for identification of novel molecular targets and for development of alternative therapeutic approaches in AD.
    Alzheimer's & dementia: the journal of the Alzheimer's Association 02/2014; 10(1):S26–S32. DOI:10.1016/j.jalz.2013.12.004 · 12.41 Impact Factor
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    • "However, due to the low concentration of A␤-oligomers, its detection is a complex task. Using different methods [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] A␤-oligomers have been detected. By flow cytometry, we detected A␤-oligomers in CSF of non-demented patients [17]. "
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