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Cited by 676Alzheimer's disease research and treatmentsDementia and Cognitive Impairment ResearchNeuroinflammation and Neurodegeneration Mechanisms

Amyloid β Protein (Aβ) in Alzheimeri's Disease Brain

Open access
Gravina, Stephen A., Ho, Libin, Eckman, Christopher B., Long, Kristin E., Otvos, Laszlo, Younkin, Linda H., Suzuki, Nobuhiro, Younkin, Steven G.·1995·Journal of Biological Chemistry
DOI 10.1074/jbc.270.13.7013
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Abstract

Biochemical and immunocytochemical analyses were performed to evaluate the composition of the amyloid beta protein (A beta) deposited in the brains of patients with Alzheimer's disease (AD). To quantitate all A beta s present, cerebral cortex was homogenized in 70% formic acid, and the supernatant was analyzed by sandwich enzyme-linked immunoabsorbent assays specific for various forms of A beta. In 9 of 27 AD brains examined, there was minimal congophilic angiopathy and virtually all A beta (96%) ended at A beta 42(43). The other 18 AD brains contained increasing amounts of A beta ending at A beta 40. From this set, 6 brains with substantial congophilic angiopathy were separately analyzed. In these brains, the amount of A beta ending at A beta 42(43) was much the same as in brains with minimal congophilic angiopathy, but a large amount of A beta ending at A beta 40 (76% of total A beta) was also present. Immunocytochemical analysis with monoclonal antibodies selective for A beta s ending at A beta 42(43) or A beta 40 confirmed that, in brains with minimal congophilic angiopathy, virtually all A beta is A beta ending at A beta 42(43) and showed that this A beta is deposited in senile plaques of all types. In the remaining AD brains, A beta 42(43) was deposited in a similar fashion in plaques, but, in addition, widely varying amounts of A beta ending at A beta 40 were deposited, primarily in blood vessel walls, where some A beta ending at A beta 42(43) was also present. These observations indicate that A beta s ending at A beta 42(43), which are a minor component of the A beta in human cerebrospinal fluid and plasma, are critically important in AD where they deposit selectively in plaques of all kinds.

AI snapshot

Written from the paper’s full text.

TL;DR

In Alzheimer’s disease (AD) brain, Aβ ending at Aβ42(43) is the predominant deposited species in cases with minimal congophilic angiopathy, while Aβ40 becomes prominent mainly in brains with substantial vascular amyloid. The authors conclude that Aβ42(43), though a minor secreted species, is critically important in AD because it deposits selectively in senile plaques of all types.

Key findings

  • In 9 of 27 AD brains with minimal congophilic angiopathy, virtually all Aβ (96%) ended at Aβ42(43); BC-05/4G8 detected 4663 ± 421 pmol/g versus BAN-50/BC-05 at 714 ± 68 pmol/g, while BA-27/4G8 detected only 216 ± 38 pmol/g.
  • In 6 AD brains with substantial congophilic angiopathy, Aβ42(43) amounts were similar to minimal-angiopathy brains (BC-05/4G8: 5089 ± 409 pmol/g; BAN-50/BC-05: 826 ± 119 pmol/g), but Aβ40 was dramatically increased (BA-27/4G8: 13,607 ± 3397 pmol/g; BAN-50/BA-27: 5001 ± 2164 pmol/g). The abstract reports 76% of total Aβ ended at Aβ40 in these brains; the Results state an average of 67%.
  • Total Aβ in 27 AD brains ranged from at least 500 to 4400 times that in plaque-free control brain; 98.5% of total Aβ required formic acid for solubilization and only 1.5% was extracted into Tris-saline.
  • Immunocytochemistry showed BC-05 and 4G8 intensely labeled all plaque types and vascular amyloid, whereas BA-27 stained vascular amyloid well but stained plaque cores less intensely and almost failed to stain uncored plaques.

Methods

  • AD and plaque-free control cerebral cortex was homogenized directly in 70% formic acid or sequentially extracted first into Tris-saline buffer with protease inhibitors and then into 70% formic acid.
  • Aβ was quantitated by sandwich ELISAs specific for forms ending at Aβ40 (BA-27/4G8 or BAN-50/BA-27) or Aβ42(43) (BC-05/4G8 or BAN-50/BC-05), with some samples fractionated by Superose 12 size exclusion chromatography.
  • Samples included an initial 3 AD and 3 control brains, then 27 AD and 6 plaque-free control brains; immunocytochemistry used formalin- or methacarn-fixed inferior temporal cortex with BA-27, BC-05, and 4G8 antibodies.

Limitations

  • The paper does not state a formal limitations section. The authors note that BAN-50 cannot capture Aβs beginning at or beyond Aβ17, so the increased Aβ detected with 4G8 may indicate considerable amino-terminally truncated Aβ, but they caution this interpretation because other factors such as isoaspartates at Aβ1 and Aβ37 may diminish BAN-50 capture.
  • The authors address the concern that BA-27 epitope destruction during fixation could distort immunocytochemistry, arguing against it because brains with minimal vascular amyloid had virtually all Aβ ending at Aβ42(43).
  • Evident from the text: subgroup analyses rely on small numbers (e.g., 9 minimal and 6 substantial congophilic angiopathy cases), and no formal statistical comparisons are reported.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1074/jbc.270.13.7013

Cites

20 of 20 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 32 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Large amounts of Aβ40 were deposited in some AD brains.

    “and large amounts of A{3C40 were deposited in some brains (Fig. 2).”
    Quote in the paperNot a substantial claim
  • Findingown data

    The remaining AD brains had increasing amounts of Aβ40.

    “the remaining brains had increasing amounts of A{3C40'”
    Quote in the paperNot a substantial claim
  • Findingreasoning

    Based on this upper limit, the total Aβ in the 27 AD brains ranged from at least 500 to 4400 times that in plaque-free control brain.

    “Based on this upper limit, the total A{3 in the 27 AD brains ranged from at least SOO to 4400 times that in plaque-free control brain.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The recovery of synthetic Aβ added to control brain applies to endogenous Aβ in AD brain.
  • Findingown data

    In the formic acid extracts of 6 brains with substantial congophilic angiopathy, Aβ40 measured with BA-27/4G8 (13607 ± 3397 pmol/g) and BAN-50/BA-27 (5001 ± 2164 pmol/g) ELISAs was dramatically increased.

    “In these brains, A{3C40' measured with BA-27/4G8 (13607 :+: 3397 pmol/g) and BAN-SOIBA-27 (SOOI :+: 2164 pmol/g) ELISAs, was dramatically increased.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The recovery of synthetic Aβ added to control brain applies to endogenous Aβ in AD brain.
  • Findingown data

    In many AD brains, virtually all Aβ was Aβ42(43).

    “In many AD brains, virtually all A{3 was A{3C42(4:Jl'”
    Quote in the paperSubstantial claim
  • May combine two claims. 14
  • Classified as probably not a substantial claim. 2

  • May combine two claims.

    Findingown data

    The BAN-50/BA-27 ELISA showed a total of 73 ± 28 pmol of Aβ/g in AD brain, whereas the BAN-50/BC-05 ELISA detected 725 ± 347 pmol/g.

    “The BAN-50IBA-27 ELISA showed a total of 73 ± 28 pmol of A{3lg in AD brain, whereas the BAN-50/BC-05 ELISA detected 725 ± 347 pmol/g (Table I).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In the AD brains, 98.5% of the total Aβ present required formic acid for solubilization and only 1.5% was extracted into Tris-saline.

    “In the AD brains, 98.S% of the total A{3 present required formic acid for solubilization and only l.S9t}was extracted into Tris-saline.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Both 4G8 and BC-05 intensely labeled the AD brain, whereas BA-27 showed very little labeling.

    “Both 4G8 and BC-OS intensely labeled the AD brain, whereas BA-27 showed very little labeling (Fig. 3).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    BA-27 stained vascular amyloid quite well but stained the cores of classic neuritic plaques less intensely and almost completely failed to stain uncored plaques or the region surrounding plaque cores.

    “BA-27 stained vascular amyloid quite well but, in contrast to BC-OS and 4G8, stained the cores of classic neuritic plaques less intensely and almost completely failed to stain uncored (diffuse and uncored neuritic) plaques or the region surrounding plaque cores.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    4G8 and BC-05 labeled uncored (diffuse and uncored neuritic) plaques, the cores of classic neuritic plaques, the region surrounding plaque cores, and vascular amyloid.

    “4G8 and BC-OS labeled uncored (diffuse and uncored neuritic) plaques, the cores of classic neuritic plaques, the region surrounding plaque cores, and vascular amyloid.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In 9 of 27 AD brains examined, there was minimal congophilic angiopathy and virtually all Aβ (96%) ended at Aβ42(43).

    “In 9 of 27 AD brains examined, there was minimal congophilic angiopathy and virtually all Ap (96%) ended at AP42(43).”
    • Also stated in: § Analysis of A{3 in 27 AD and 6 · plain
      “Virtually all A{3 in the formic acid extracts from these 9 brains (96%) ended at A{342(43)”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingcitation

    The immunocytochemical results demonstrate that BC-05 intensely stains all types of senile plaques, that vessels are stained by both BC-05 and BA-27, and that BA-27 stains plaques poorly.

    “The immunocytochemical results shown here and in a recent report by Iwatsubo et al. (21) demonstrate that BC-05 intensely stains all types of senile plaques, that vessels are stained by both BC-OS and BA-27, and that BA-27 stains plaques poorly, in many cases only faintly staining occasional cored plaques (Fig. 3).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [21] Iwatsubo, 1994, Neuron source

  • May combine two claims.

    Findingown data

    In 3 AD brains, the BA-27/4G8 ELISA showed a total of 93 ± 45 pmol of Aβ/g whereas the BC-05/4G8 ELISA showed 3200 ± 1350 pmol of Aβ/g.

    “In the 3 AD brains, the BA-27/4GB ELISA showed a total of93 ± 45 pmol of A,B/g whereas the BC-05/4G8 ELISA showed 3200 ± 1350 pmol of A,BIg (Table I).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    It appears that deposition of Aβ42(43) in senile plaques is fundamental to AD pathogenesis with additional deposition of Aβ40, primarily in blood vessel walls, occurring in some cases.

    “Thus, it a ppears t hat deposition of A{3C42(43) in senile plaq ues is fundamental to AD path ogenesis with additi ona l deposition of A{3C40' prim aril y in blood vessel wa lls, occurring in some cases.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    This finding is consistent with previous reports that most of the Aβ in AD brains is amino-terminally truncated or modified.

    “Th is finding is consistent with pr evious re ports (15,17,18) that most of the A{3 in AD brains is amino-ter mi na lly trunca te d or modifi ed.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [15] Roher, 1993, J. Biol. Chem. source
    • cites [17] Miller, 1993, Arch. Biochem. source
    • cites [18] Gowing, 1994, J. Biol. Chem. source

  • May combine two claims.

    Study design and conductcitation

    The sandwich ELISAs used specifically detect Aβs ending at Aβ40 or at Aβ42(43).

    “The monoclonal antibodies employed were BAN-50 (anti-A{31-16), 4G8 (anti-Af3l7-24) (19), BA-27, which is specific for A{3 ending at A{340, and BC-05, which is specific for A{3 ending at A{342(43).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [9] Suzuki, 1994, Science source
    • cites [19] Kim, 1988, Neurosci. Res. Commun.

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In the brains of patients with Alzheimer's disease, amyloid composed of 4-kDa amyloid β protein (Aβ) is deposited in senile plaques and in blood vessel walls.

    “In the brains of patients with Alzheimer's disease (AD),!amyloid composed of 4-kDa amyloid {3 protein (A{3) is deposited in senile plaques and in blood vessel walls.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [1] Yamaguchi, 1988, Acta Neuropathol. source
    • cites [2] Masliah, 1990, Am. J. Pathol.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Normal processing of β-APP secretes 4-kDa Aβ that is readily detected in human cerebrospinal fluid and in medium conditioned by cultured cells.

    “Recently, we and others have shown that normal processing of the large amyloid f3 protein precursor ({3-APP) secretes 4-kDa A(3 that is readily detected in human cerebrospinal fluid and in medium conditioned by cultured cells (3)(4)(5)(6).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [3] Seubert, 1992, Nature source
    • cites [4] Haass, 1992, Nature source
    • cites [5] Shoji, 1992, Science source

  • May combine two claims.

    Premisecitation

    In trisomy 21 brains, as plaques developed, BC-05 variably showed intense staining of all plaques as well as some staining of blood vessel walls whereas BA-27 intensely stained blood vessels and showed increasing staining of Aβ40 in plaques, particularly mature cored plaques, although it never stained plaques to the extent observed with BC-05.

    “As t his occurred, BC-05 in varia bly showed intense staini ng of all plaq ues as well as some staining of blood ves sel wa lls whereas BA-27 intensely staine d blood vess els a nd showed increa sing stai ning of A{3C40 in plaques, par ticul a rly ma t ure cored pla qu es, a lthough it never stained plaques to t he exte nt observed with BC-05.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [22] Iwatsubo, 1995, Ann. Neurol.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim.

    Premisecitation

    SDS-insoluble amyloid in senile plaque cores is primarily Aβ1-42.

    “Recent reports using this approach, particularly those of Roher and his colleagues, indicate that the SDS-insoluble amyloid in senile plaque cores is primarily A(31-42 (15,17)”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [15] Roher, 1993, J. Biol. Chem. source
    • cites [17] Miller, 1993, Arch. Biochem. source

  • May combine two claims.

    Premisecitation

    In trisomy 21 brains, Aβ42(43) stained by BC-05 was deposited first in diffuse plaques, and there was essentially no staining by BA-27.

    “In th ese br ai ns, A{3C42(43l staine d by BC-05 was deposited fir st in diffu se plaq ues , an d there was esse ntia lly no staining by BA-27.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [22] Iwatsubo, 1995, Ann. Neurol.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

16 of 16

  • The paper relies on this without support.

    The recovery of synthetic Aβ added to control brain applies to endogenous Aβ in AD brain.

    “To assess Af3 recovery, synthetic Af3 (500 pmol of A{31-4o plus 500 pmol of Af31-42, Bachem) was added to samples of cerebral cortex (-0.5 g) from control brains prior to homogenization.”
1 of 1

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Both formic acid-requiring Aβ42 and Aβ40 continued to increase substantially from 12 to 23 months, reaching levels like those seen in AD brain.

    “and both forms continued to increase substantially from 12 to 23 months, reaching levels like those seen in the AD brain (Gravina et al., 1995).”

    From Age-Dependent Changes in Brain, CSF, and Plasma Amyloid β Protein in the Tg2576 Transgenic Mouse Model of Alzheimer's Disease (2001) · cites this paper as Gravina et al., 1995

    The ‘Analysis of Aβ in 27 AD and 6 Plaque-free Control Brains’ section (page unavailable) measures formic-acid-requiring Aβ in AD brains, including forms ending at Aβ42(43) and Aβ40. It provides AD-brain levels as a reference, but does not study a 12-to-23-month increase or establish that the levels reached at 23 months were comparable to those in AD brain. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

  • In the authors' previous examination of insoluble Aβ in 27 AD brains, Aβ42 predominated in 70% and in 33% there was essentially no Aβ40 deposited.

    “In our previous examination of insoluble A␤ in 27 AD brains (Gravina et al., 1995), A␤42 predominated in 70% and, in 33%, there was essentially no A␤40 deposited.”

    From Age-Dependent Changes in Brain, CSF, and Plasma Amyloid β Protein in the Tg2576 Transgenic Mouse Model of Alzheimer's Disease (2001) · cites this paper as Gravina et al., 1995

    The Abstract and the discussion of the 27-brain analysis report that virtually all Aβ ended at Aβ42(43) in 9 of 27 AD brains, supporting the approximately 33% with essentially no Aβ40 deposited. The discussion says Aβ40 was the major form in six cases, but it does not establish the claimed 70% figure for Aβ42 predominance across all 27 brains. (LLM, conf=0.82)

    Experimental — accuracy not yet measured

  • In the 30% of AD cases in which Aβ40 was the predominant species deposited, there was typically prominent congophilic angiopathy.

    “In the 30% in which A␤40 was the predominant species deposited, there was typically prominent congophilic angiopathy.”

    From Age-Dependent Changes in Brain, CSF, and Plasma Amyloid β Protein in the Tg2576 Transgenic Mouse Model of Alzheimer's Disease (2001) · cites this paper as Gravina et al., 1995

    The Results report that Aβ40 was the major form deposited in six AD brains with substantial congophilic angiopathy. They do not establish the claimed 30% figure: those six were selected for separate analysis from a series of 27 brains, and the paper does not give a percentage of all cases in which Aβ40 predominated. (LLM, conf=0.88)

    Experimental — accuracy not yet measured

  • In most AD patients, very little Aβ40 is deposited in the brain, but in ~33%, extraordinary amounts of Aβ40 are deposited, and most of these patients show substantial amyloid angiopathy.

    “In most AD patients, very little A␤40 is deposited in the brain, but in ϳ33%, extraordinary amounts of A␤40 are deposited, and most of these patients show substantial amyloid angiopathy (Gravina et al., 1995).”

    From Age-Dependent Changes in Brain, CSF, and Plasma Amyloid β Protein in the Tg2576 Transgenic Mouse Model of Alzheimer's Disease (2001) · cites this paper as Gravina et al., 1995

    The Abstract and the analysis of 27 AD brains report that 9 of 27 had virtually no Aβ40, while the other 18 had increasing amounts. The paper links abundant Aβ40 with substantial angiopathy in six brains, but it does not establish that most patients deposited very little Aβ40 or that approximately 33% deposited extraordinary amounts. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

  • Aβ40 accumulates to a variable degree in the human AD brain.

    “accumulates to a variable degree in the human AD brain”

    From Aβ40 Inhibits Amyloid Deposition<i>In Vivo</i> (2007) · cites this paper as Gravina et al., 1995

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Conflicting percentages of Aβ ending at Aβ40

    Major

    For the six brains with substantial congophilic angiopathy, the abstract states that 76% of total Aβ ended at Aβ40, while the results state that the average was 67%. Both statements describe the same six-brain group.

1 of 1

Cites

Flagged first, then by citations

Research works printed but not linked: 4

  1. Masliah, 1990, Am. J. Pathol., 137, 1293
  2. Kim, 1988, Neurosci. Res. Commun., 2, 121
  3. Suzuki, 1994, Am. J. Pathol., 145, 452
  4. Iwatsubo, 1995, Ann. Neurol.

Cited by

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Related

Authors
Gravina, S. A., Ho, L., Eckman, C. B., Long, K. E., Otvos, L., Younkin, L. H., Suzuki, N., & Younkin, S. G.
Affiliations
  • Case Western Reserve University (US)
  • Takeda (Japan) (JP)
Corresponding author
Younkin, Steven G.
ORCID
Venue
Journal of Biological Chemistry
Publisher
Elsevier BV
Published
1995-03
Volume
270
Issue
13
Pages
7013-7016
ISSN
0021-9258 (ISSN-L)
DOI
10.1074/jbc.270.13.7013
OpenAlex
W1618236677
Cited by
676
References
20
Citations by year
2026: 8 · 2025: 16 · 2024: 19 · 2023: 21 · 2022: 23 · 2021: 33 · 2020: 33 · 2019: 22 · 2018: 18 · 2017: 22 · 2016: 27 · 2015: 20 · 2014: 22 · 2013: 24 · 2012: 24
FWCI
17.94
Type
journal article
Language
en
Open access
Licence
Locations
  • Journal of Biological Chemistry (publishedVersion, cc-by)
  • PubMed (publishedVersion)
Funders
  • National Institutes of Health (5r01ag012685-04)
  • National Institute on Aging (AG06656, R01AG006656, AG12685)
Topics
  • Health Sciences › Medicine › Physiology › Alzheimer's disease research and treatments
  • Health Sciences › Medicine › Psychiatry and Mental health › Dementia and Cognitive Impairment Research
  • Life Sciences › Neuroscience › Neurology › Neuroinflammation and Neurodegeneration Mechanisms
Keywords
amyloid-beta, Alzheimer's disease, amyloid-beta 42, Aβ40, cerebral amyloid angiopathy, amyloid plaques, cerebral cortex, vascular wall, amyloid deposition, cerebrospinal fluid
MeSH terms
Alzheimer Disease, Cerebral Cortex, Chromatography, Gel, Enzyme-Linked Immunosorbent Assay, Humans, Immunohistochemistry, Reference Values, Temporal Lobe, Amyloid beta-Peptides

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