| 1. |
- Aho, Leena, et al.
(författare)
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Immunohistochemical Visualization of Amyloid-β Protein Precursor and Amyloid-β in Extra- and Intracellular Compartments in the Human Brain
- 2010
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 20:4, s. 1015-1028
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Tidskriftsartikel (refereegranskat)abstract
- Amyloid-beta (Abeta) peptide, a cleavage product of the amyloid-beta protein precursor (AbetaPP), has been reported to be detected in the intracellular compartment. Most studies reporting the presence of intracellular Abeta are based on the use of immunohistochemistry. In this study, the presence of AbetaPP and Abeta was assessed by applying immunohistochemistry in postmortem human brain tissue samples obtained from 10 neurologically intact subjects, the youngest being 2 years of age, one aged with mild cognitive impairment, 14 neurologically diseased, and in one brain biopsy sample obtained from a subject with normal pressure hydrocephalus. Intracellular immunoreactivity was detected in all ages independent of the disease state or existence of extracellular Abeta aggregates with all antibodies directed to AbetaPP, with three Abeta antibodies (4G8, 6E10, and 82E1), clones that are unable to distinguish Abeta from AbetaPP. These results suggest that it is AbetaPP rather than Abeta that is detected intracellularly when using the antibodies listed above. Furthermore, the staining results varied when different pretreatment strategies were applied. Interestingly intracellular Abeta was detected with antibodies directed to the C-terminus of Abeta (neoepitope) in subjects with Alzheimer's disease. The lack of intracellular immunoreactivity in unimpaired subjects, when using antibodies against neoepitopes, may be due to a lack or a low level of the protein that is thus undetectable at light microscopic level by immunohistochemistry method. The staining results and conclusions depended strongly on the chosen antibody and the pretreatment strategy and thus multiple antibodies must be used when assessing the intracellular accumulation of Abeta.
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| 2. |
- Pikkarainen, Maria, et al.
(författare)
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The effect of prolonged fixation time on immunohistochemical staining of common neurodegenerative disease markers
- 2010
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Ingår i: Journal of Neuropathology and Experimental Neurology. - 0022-3069 .- 1554-6578. ; 69:1, s. 40-52
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Tidskriftsartikel (refereegranskat)abstract
- The goals of this study were to determine the effects of prolonged fixation time and to optimize antigen retrieval (AR) methods on immunohistochemical (IHC) staining of common neurodegenerative disease markers. A panel of commercial antibodies (Abs) to amyloid-beta, ubiquitin, p62/sequestosome, tau, and alpha-synuclein was applied to a 2-mm tissue microarray using several AR methods. The IHC outcomes were assessed in sections that included 2 types of specimens taken from 20 postmortem brains: short-term fixation of up to 70 days before paraffin embedment and long-term fixation of up to 14 years in formalin. Good amyloid-beta IHC staining was obtained with all amyloid-beta Abs applied when a formic acid AR method was used, even after 14 years of fixation. Ubiquitin immunoreactivity was also optimally labeled with this method. The p62/sequestosome IHC outcome was optimal for tissue fixed up to 10 years, but only when the p62-lck-ligand-Ab with heat AR method was used. All hyperphosphorylated tau Abs tested worked with fixation up to 10 years, in particular with the heat AR method, whereas Abs against tau isoforms RD3 and RD4 were applicable only when the fixation time was 6 months or shorter. alpha-Synuclein-immunoreactive structures were visualized up to 14 years but only by the use of Syn42-Ab after formic acid AR or after a combination of heat and formic acid methods.
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