Methods for Analysis of Amyloid-β Aggregates

Abstract

Amyloid-β protein (Aβ) accumulation is one of the major hallmarks of Alzheimer's disease and plays a crucial role in its pathogenesis. Aβ aggregates into fibrils, but rather than these end-products of the aggregation process, intermediate species, referred to as oligomers, have been identified as the most neurotoxic Aβ aggregates. To characterize the different Aβ species and to study the aggregation process, a wide range of techniques has been applied over the past years. These techniques aim to visualize the different Aβ species and study their structure, to separate them, and to quantify the aggregated Aβ forms by immunology-based methods. In this review, we provide an overview and discussion of the most important techniques used for these aims. Often a combination of techniques will be appropriate to obtain the most optimal information.

Neuronal loss without amyloid‐β deposits in the thalamus and hippocampus in the late period after middle cerebral artery occlusion in cynomolgus monkeys

“…For Thioflavin S (ThS) staining, brain sections were incubated with 1% of thioflavin S (T1892, Sigma Aldrich) dissolved in 70% of ethanol for 10 minutes and followed by two washes of 70% of ethanol for 10 minutes each (5). For Congo Red (CR) staining, brain sections were stained using Amyloid Stain, Congo Red, kit (HT60, Sigma Aldrich) according to the manufacturer's operating instructions (5). The brain sections from transgenic AD mice 5XFAD (9 months old) were used as a positive staining control.…”

“…Briefly, citrate buffer pre-treated sections (10 minutes, 85°C) were treated with 3% of hydrogen peroxide for 15 minutes for quenching endogenous peroxidase activity, and blocked with 5% normal goat serum for 1 h at room temperature. Then, the sections were incubated with the following primary antibodies at 4°C overnight: mouse anti-Aβ [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] (1:400 (43,55). Brain tissue from AD patients and AD transgenic mice were used as positive control.…”

A possible Fourier transform infrared‐based plasma fingerprint of angiotensin‐converting enzyme inhibitor‐induced reversal of endothelial dysfunction in diabetic mice

“…However, in each of these 3 pathologies such as systemic hypertension, pulmonary hypertension and diabetes that are linked to endothelial dysfunction, alterations in the secondary structure of proteins are visible, suggesting that this type of changes may indeed constitute the reliable FTIR‐based fingerprint of endothelial dysfunction. Given the fact that amyloidogenic processing by endothelium is linked to NO‐dependent function and that endothelial dysfunction is a hallmark of numerous diseases , FTIR‐based assessment of amide II to amide I ratio supplemented by other complementary techniques such as immunology and separation‐based methods, electron microscopy or circular dichroism spectroscopy , can prove useful to evaluate the importance of amyloidogenesis in various diseases. Obviously, validation of this approach is warranted.…”

The future of blood‐based biomarkers for Alzheimer's disease

“…The detection and quantitation of Aβ oligomers could be helpful in studies aimed at elucidating Aβ aggregation mechanisms and determining Aβ species neurotoxicity [94]. In a recent study, a novel enzyme-linked immunosorbent assay method was used to inspect in vivo levels of Aβ oligomers vs. Aβ monomers in plasma and brain tissue of patients with sporadic and familial AD [95].…”