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Cited by 1,064Alzheimer's disease research and treatmentsDementia and Cognitive Impairment ResearchNeuroinflammation and Neurodegeneration Mechanisms

Age-Dependent Changes in Brain, CSF, and Plasma Amyloid β Protein in the Tg2576 Transgenic Mouse Model of Alzheimer's Disease

Open access
Kawarabayashi, Takeshi, Younkin, Linda H., Saido, Takaomi C., Shoji, Mikio, Ashe, Karen Hsiao, Younkin, Steven G.·2001·The Journal of Neuroscience
DOI 10.1523/jneurosci.21-02-00372.2001PMC PMC6763819
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Abstract

The accumulation of amyloid β protein (Aβ) in the Tg2576 mouse model of Alzheimer's disease (AD) was evaluated by ELISA, immunoblotting, and immunocytochemistry. Changes in Aβ begin at 6–7 months as SDS-insoluble forms of Aβ42 and Aβ40 that require formic acid for solubilization appear. From 6 to 10 months, these insoluble forms increase exponentially. As insoluble Aβ appears, SDS-soluble Aβ decreases slightly, suggesting that it may be converting to an insoluble form. Our data indicate that it is full-length unmodified Aβ that accumulates initially in Tg2576 brain. SDS-resistant Aβ oligomers and most Aβ species that are N-terminally truncated or modified develop only in older Tg2576 mice, in which they are present at levels far lower than in human AD brain. Between 6 and 10 months, when SDS-insoluble Aβ42 and Aβ40 are easily detected in every animal, histopathology is minimal because only isolated Aβ cores can be identified. By 12 months, diffuse plaques are evident. From 12 to 23 months, diffuse plaques, neuritic plaques with amyloid cores, and biochemically extracted Aβ42 and Aβ40 increase to levels like those observed in AD brains. Coincident with the marked deposition of Aβ in brain, there is a decrease in CSF Aβ and a substantial, highly significant decrease in plasma Aβ. If a similar decline occurs in human plasma, it is possible that measurement of plasma Aβ may be useful as a premorbid biomarker for AD.

AI snapshot

Written from the paper’s full text.

TL;DR

In Tg2576 mice, formic acid-requiring Aβ42 and Aβ40 appear at 6–7 months and rise exponentially, while SDS-soluble Aβ declines slightly; plaques become evident later. As brain Aβ deposits, CSF and plasma Aβ decline, suggesting plasma Aβ may be a premorbid biomarker if a similar decline occurs in humans.

Key findings

  • Formic acid-requiring Aβ42 and Aβ40 first appeared at ~7 months and were unequivocal by 8–9 months; between 6 and 12 months they increased exponentially and continued rising from 12 to 23 months to AD-like levels. SDS-soluble Aβ decreased slightly as insoluble Aβ appeared (Spearman: Aβ42 p = 0.02; Aβ40 p = 0.003; TBS/Triton fractions decreased, p = 0.009 for TBS Aβ42, TBS Aβ40, and Triton Aβ40; p = 0.05 for Triton Aβ42).
  • Histopathology lagged biochemistry: at 6–10 months only isolated cored plaques were seen despite insoluble Aβ in every animal; diffuse plaques became evident by 12 months, and from 12–23 months diffuse plaques, neuritic plaques with cores, and extracted Aβ42/Aβ40 increased to levels like those in AD brain.
  • In 21–23 month Tg2576 brain, only 5% of insoluble Aβ was N-terminally truncated or modified, versus 69–85% in AD brain; N3(pE) appeared late (16–23 months), and N11(pE) was not detected in Tg2576 but was detected in AD. Tg2576 initially accumulates full-length unmodified Aβ; oligomers and most modified forms appear only in older mice and at far lower levels than in AD.
  • Coincident with brain deposition, CSF Aβ42 declined (p = 0.03 in text; Fig. 7 legend reports p = 0.02) and plasma Aβ42 and Aβ40 showed highly significant decreases (p = 0.008 and p = 0.006, respectively); nontransgenic littermates showed no decline, with a slight upward trend.

Methods

  • Tg2576 mice and nontransgenic littermates were killed at 1–25 months; plasma was collected in 0.1% EDTA, CSF was obtained by the Carp method, and one hemibrain was frozen while the other was fixed.
  • Brain was sequentially extracted by a four-step protocol (TBS, 1% Triton X-100, 2% SDS, 70% formic acid) or a two-step protocol (2% SDS then 70% formic acid); Aβ42/Aβ40 were measured by sandwich ELISA, immunoblotting, and immunocytochemistry using domain-specific antibodies.
  • CSF/plasma sample sizes were Tg2576 CSF n = 45 and plasma n = 131 across age groups; nontransgenic CSF n = 10 and plasma n = 31. AD brains were stained in parallel (seven), and Table 2 AD groups were n = 6 with substantial congophilic angiopathy and n = 9 with minimal. Analyses included Spearman rank correlation and Mann-Whitney comparisons.

Limitations

  • The paper has no formal limitations section; the authors state unresolved questions: why Tg2576 deposits large amounts of Aβ40, and whether the late development and relative paucity of modified or oligomeric Aβ reflects the shorter aggregation time or fundamental human/mouse biochemical differences.
  • Evident: Tg2576 resembles the AD subgroup with Aβ40 predominance and congophilic angiopathy rather than most AD; only 5% of insoluble Aβ is N-terminally modified/truncated versus 69–85% in AD, N11(pE) is absent, and the authors mention minimal neurofibrillary pathology and neuronal loss in Tg2576 brain, limiting generalizability.
  • Evident: SDS versus formic acid partitioning depends on extraction protocol (e.g., 21-month Tg2576: 66.2% SDS/33.1% FA four-step vs 10.6% SDS/89.4% FA two-step; AD: 81.5%/18.2% vs 13.8%/86.2%), so soluble/insoluble percentages are method-dependent. The plasma biomarker implication is explicitly conditional (“If a similar decline occurs in human plasma”).

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

Integrity signals

Registry

Crossref · 10.1523/jneurosci.21-02-00372.2001

Cites

41 of 41 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

9 of 56 cited sources checked · 5 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    In the authors' previous study, ELISAs for Aβx-42 and Aβx-40 showed that most of the Aβ in AD brain is N-terminally truncated or modified.

    “In our previous study (Gravina et al., 1995), ELISAs for A␤x-42 (BC-05/4G8) and A␤x-40 (BA-27/4G8) showed that most of the A␤ in AD brain is N-terminally truncated or modified.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Gravina et al., 1995 source
  • Premisecitation

    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.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Gravina et al., 1995 source

      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
  • Findingcitation

    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).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Gravina et al., 1995 source

      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
  • Premisecitation

    Much of the Aβ in AD brain is N-terminally truncated or modified.

    “Much of the A␤ in AD brain is N-terminally truncated or modified (Saido et al., 1995(Saido et al., , 1996;;Hosoda et al., 1998)”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Saido et al., 1995 source
    • cites Saido et al., 1996 source
    • cites Hosoda et al., 1998 source
  • Findingown data
    § Age-Dependent Changes in Brain, CSF, and Plasma Amyloid ␤ Protein in the Tg2576 Transgenic Mouse Model of Alzheimer's Disease

    The N-terminally truncated or modified Aβ species in older Tg2576 mice are present at levels far lower than in human AD brain.

    “in which they are present at levels far lower than in human AD brain.”
    Quote in the paperNot a substantial claim
  • May combine two claims. 45
  • Classified as probably not a substantial claim. 26

  • May combine two claims.

    Interpretationown data

    N-terminally modified or truncated forms of Aβ, which predominate in AD brain, are minor species in Tg2576 brain that only begin to appear in very old mice.

    “Thus, it appears that N-terminally modified or truncated forms of A␤, which predominate in AD brain (Saido et al., 1995(Saido et al., , 1996;;Hosoda et al., 1998), are minor species in Tg2576 brain that only begin to appear in very old mice.”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Saido et al., 1995 source
    • cites Saido et al., 1996 source
    • cites Hosoda et al., 1998 source

  • May combine two claims.

    Premisecitation

    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.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Gravina et al., 1995 source

      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

  • May combine two claims.

    Findingown data

    Virtually all Aβ terminated at Aβ42 in the two AD brains examined, as occurs in approximately 33% of AD cases.

    “In contrast, virtually all A␤ terminated at A␤42 in the two AD brains examined (Fig. 5 K, L), as occurs in ϳ33% of AD cases (Gravina et al., 1995).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Gravina et al., 1995 source

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

    Premisecitation

    It has been suggested that the formation of SDS stable Aβ oligomers may be an early event in AD.

    “and it has been suggested that the formation of SDS stable A␤ oligomers may be an early event in AD (Enya et al., 1999).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Enya et al., 1999 source

  • May combine two claims.

    Premisecitation

    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).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Gravina et al., 1995 source

      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

  • May combine two claims.

    Findingown data
    § Age-Dependent Changes in Brain, CSF, and Plasma Amyloid ␤ Protein in the Tg2576 Transgenic Mouse Model of Alzheimer's Disease

    From 12 to 23 months, diffuse plaques, neuritic plaques with amyloid cores, and biochemically extracted Aβ42 and Aβ40 increase to levels like those observed in AD brains.

    “From 12 to 23 months, diffuse plaques, neuritic plaques with amyloid cores, and biochemically extracted A␤42 and A␤40 increase to levels like those observed in AD brains.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Age-Dependent Changes in Brain, CSF, and Plasma Amyloid ␤ Protein in the Tg2576 Transgenic Mouse Model of Alzheimer's Disease

    SDS-resistant Aβ oligomers and most Aβ species that are N-terminally truncated or modified develop only in older Tg2576 mice.

    “SDS-resistant A␤ oligomers and most A␤ species that are N-terminally truncated or modified develop only in older Tg2576 mice”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    These Aβ oligomers are not detectable at 8 months but are definitely present by 12 months and increase substantially thereafter.

    “As shown in Figures 4 A-D and 5G, these oligomers are not detectable at 8 months but are definitely present by 12 months and increase substantially thereafter.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Cored plaques increased between 7 and 10 months, but even at 10 months only a few cores were present in each section.

    “They increased between 7 and 10 months but, even at 10 months, only a few cores were present in each section (Fig. 2 K, L).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    In 21 month Tg2576 brain, 66.2% of total Aβ was extracted into SDS versus 33.1% into formic acid with four-step extraction, and 10.6% into SDS versus 89.4% into formic acid with two-step extraction.

    “The relevant percent-ages in 21 month Tg2576 are 66.2% SDS versus 33.1% FA with the four-step extraction and 10.6% SDS versus 89.4% FA with the two-step procedure”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In aging nontransgenic littermates, there was no suggestion of a decline in Aβ because Aβ42 and Aβ40 both showed a slight upward trend in CSF and plasma with aging.

    “In these nontransgenic mice, there was no suggestion of a decline in A␤ because A␤42 and A␤40 both showed a slight upward trend in CSF (Fig. 7G,H ) and plasma (Fig. 7 I, J ) with aging.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    SDS-insoluble 4 kDa Aβ labeled by both BAN-50 and 4G8 appeared at 6-8 months and increased substantially by 10 months.

    “SDS-insoluble 4 kDa A␤ labeled by both BAN-50 (Fig. 4 B) and 4G8 (Fig. 4 D) appeared at 6 -8 months and increased substantially by 10 months.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In AD brains, 81.5% of total Aβ was extracted into SDS versus 18.2% into formic acid with four-step extraction, and 13.8% into SDS versus 86.2% into formic acid with two-step extraction.

    “and in AD brains, 81.5% SDS versus 18.2% FA with four-step and 13.8% SDS versus 86.2% FA with two-step extraction.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In Tg2576 and AD brains in which there is Aβ deposition, the relative amounts of Aβ extracted into SDS and formic acid with the two methods are considerably different, with a much higher percentage of total Aβ extracted into SDS in the four-step method.

    “In Tg2576 and AD brains, in which there is A␤ deposition, the relative amounts of A␤ extracted into SDS and FA with the two methods are considerably different.A much higher percentage of total A␤ is extracted into SDS in the four-step method.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    In Tg2576 brains, diffuse plaques are not observed in appreciable number until 12 months, 4 months after biochemically detectable alterations in Aβ have begun in every animal.

    “In Tg2576 brains, diffuse plaques are not observed in appreciable number until 12 months, 4 months after biochemically detectable alterations in A␤ have begun in every animal.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The decline in CSF Aβ42 was accompanied by a decline in CSF Aβ40, although this decrease did not achieve significance.

    “and it was accompanied by a decline in CSF A␤40, although this decrease did not achieve significance.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    More sensitive sandwich ELISA assays detected small amounts of SDS-extractable Aβ in all systemic organs (10-24 pmol/gm), but the amount of SDS-extractable Aβ in the brain was much larger (400 pmol/gm).

    “The more sensitive sandwich ELISA assays (Fig. 1 H) were able to detect small amounts of SDS-extractable A␤ in all systemic organs (10 -24 pmol/gm), but the amount of SDSextractable A␤ in the brain was much larger (400 pmol/gm).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    AβN3-pyroglutamate (N3(pE)) appears late in Tg2576 brain, accumulating between 16 and 23 months.

    “Histochemical analysis (Fig. 6) showed that A␤N3-pyroglutamate (N3(pE)) appears late in Tg2576 brain, accumulating between 16 and 23 months.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Plasma Aβ42 (p=0.008) and Aβ40 (p=0.006) both showed highly significant decreases that paralleled the marked accumulation of brain Aβ and the decline in CSF Aβ that occurred between 6 and 23 months.

    “Remarkably, plasma A␤42 ( p ϭ 0.008) and A␤40 ( p ϭ 0.006) both showed highly significant decreases (Fig. 7 E, F ) that paralleled the marked accumulation of brain A␤ and the decline in CSF A␤ that occurred between 6 and 23 months.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The Tg2576 transgenic mouse model is a valid model for studying human AD Aβ deposition.

  • May combine two claims.

    Findingown data

    In Tg2576 brain, only 5% of insoluble Aβ is N-terminally truncated or modified, whereas in AD brain the corresponding percentage is 69-85%.

    “This indicates that, in Tg2576 brain, only 5% of insoluble A␤ is N-terminally truncated or modified, whereas in AD brain, the corresponding percentage is 69 -85% (Table 2).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    BA-27 and BC-05 analysis confirmed that Aβs terminating at both Aβ40 and Aβ42 accumulate in aging Tg2576 brain, with Aβ40 predominating.

    “This analysis confirmed that A␤s terminating at both A␤40 and A␤42 accumulate in aging Tg2576 brain with A␤40 predominating (Figs. 2, 5 K, L).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The definite biochemical change that occurs by 10 months in Tg2576 mice is accompanied by minimal histological evidence of Aβ deposition, although single plaque cores can be observed in many sections.

    “The definite biochemical change that occurs by 10 months in Tg2576 mice is accompanied by minimal histological evidence of A␤ deposition, although single plaque cores can be observed in many sections.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The total amounts of Aβ42 and Aβ40 extracted by two-step and four-step protocols are virtually identical, although slightly more Aβ is extracted with the four-step method.

    “The total amounts of A␤42 and A␤40 extracted by two-step and four-step protocols are virtually identical, although slightly more A␤ is extracted with the four-step method.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingreasoning

    As insoluble (FA-requiring) Aβ appears at 6-9 months, the remaining Aβ in the brain (SDS-extracted in two-step, or TBS-and Triton-extracted in four-step) decreases slightly.

    “As insoluble (FA-requiring) A␤ appears at 6 -9 months, the remaining A␤ in the brain (SDS-extracted in two-step, or TBS-and Triton-extracted in four-step) decreases slightly”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In SDS extracts, BAN-50 labeled far more 4 kDa Aβ in Tg2576 than in AD brains, whereas 4G8 labeled large amounts of Aβ in both Tg2576 and AD brains.

    “Similarly, in SDS extracts, BAN-50 labeled far more 4 kDa A␤ in Tg2576 than in AD brains (Fig. 5A), whereas 4G8 labeled large amounts of A␤ in both Tg2576 and AD brains (Fig. 5C).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The unequivocal biochemical change that occurred between 6 and 10 months was accompanied by minimal immunocytochemical evidence of Aβ deposition, although isolated cored plaques were observed in virtually every section on careful inspection.

    “Remarkably, the unequivocal biochemical change that occurred between 6 and 10 months was accompanied by minimal immunocytochemical evidence of A␤ deposition, although isolated, cored plaques were observed in virtually every section on careful inspection (Fig. 2).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    These early cored plaques were stained by Congo red and showed green birefringence with polarized light.

    “These early cored plaques were stained by Congo red and showed green birefringence with polarized light (data not shown).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Both meningeal and parenchymal blood vessels in the brain showed progressive Aβ accumulation.

    “Both meningeal and parenchymal blood vessels in the brain also showed progressive A␤ accumulation.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Moderate levels of transgenic human APP were present in Tg2576 heart, skin, bone, and muscle, and there was some human APP in pancreas, stomach, and large intestine.

    “Moderate levels of transgenic human APP were present in Tg2576 heart, skin, bone, and muscle, and there was some human APP in pancreas, stomach, and large intestine (Fig. 1 D).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    SDS-soluble Aβ decreases transiently at 8 months, when SDS-resistant, formic acid-soluble Aβ appears.

    “Note that SDS-soluble A␤ decreases transiently at 8 months, when SDS-resistant, formic acid-soluble A␤ appears.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    From 10 to 21 months, there is a rapid increase in both diffuse and cored plaques in Tg2576 brain and a coordinate marked increase in SDS-dissociable and FA-requiring Aβ, with both the biochemical and histological changes rising to levels like those observed in human AD.

    “Our immunohistochemical and biochemical analyses show that, from 10 to 21 months, there is a rapid increase in both diffuse and cored plaques in Tg2576 brain and a coordinate marked increase in SDS-dissociable and FA-requiring A␤, with both the biochemical and histological changes rising to levels like those observed in human AD.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Plasma Aβ is even higher in NORβ 0304 (1400 pM Aβ42; 5600 pM Aβ40) than in Tg2576, but NORβ 0304 mice do not develop age-dependent Aβ deposition in brain.

    “Significantly, plasma A␤ is even higher in NOR␤ 0304 (1400 pM A␤42; 5600 pM A␤40) than in Tg2576, but NOR␤ 0304 mice do not develop age-dependent A␤ deposition in brain.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The decline for CSF Aβ42 is significant (p=0.02), and the declines for plasma Aβ40 and Aβ42 are highly significant (Aβ42, p=0.008; Aβ40, p=0.006; Spearman's rank correlation for the 6-23 month age range).

    “The decline for CSF A␤42 is significant ( p ϭ 0.02), and the declines for plasma A␤40 and A␤42 are highly significant (A␤42, p ϭ 0.008; A␤40, p ϭ 0.006; Spearman's rank correlation for the 6 -23 month age range).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    After this early period, oligomers and most modified forms (e.g., forms beginning at 3pE) appear, but at levels far below those observed in AD brain.

    “After this early period, oligomers and most modified forms (e.g., forms beginning at 3pE) appear, but at levels far below those observed in AD brain.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Coincident with the marked deposition of Aβ42 and Aβ40 in brain, there is not only a decline in CSF Aβ but also a substantial, highly significant decrease in plasma Aβ42 and Aβ40.

    “This analysis showed that, coincident with the marked deposition of A␤42 and A␤40 in brain, there is not only a decline in CSF A␤ but also a substantial, highly significant decrease in plasma A␤42 and A␤40.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The Tg2576 transgenic mouse model is a valid model for studying human AD Aβ deposition.

  • May combine two claims.

    Findingown data

    From 15 to 23 months, Aβ deposits increase in number and size and are detected both as cored plaques labeled by both BC-05 and BA-27 and as diffuse plaques, which are selectively labeled by BC-05.

    “From 15 to 23 months ( C-H), A␤ deposits increase in number and size and are detected both as cored plaques labeled by both BC-05 and BA-27 and as diffuse plaques, which are selectively labeled by BC-05.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In Tg2576 mice, the APP K670N,M671L transgene is expressed at highest level in the brain, but there is also substantial expression in other organs.

    “In Tg2576 mice, the APP K670N,M671L transgene is expressed at highest level in the brain, but there is also substantial expression in other organs (Fig. 1)”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    The Tg2576 model is like this latter group of AD patients in that there is marked congophilic angiopathy and the deposition of a large amount of Aβ40.

    “The Tg2576 model is like this latter group of AD patients in that there is marked congophilic angiopathy and the deposition of a large amount of A␤40.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationown data
    § Age-Dependent Changes in Brain, CSF, and Plasma Amyloid ␤ Protein in the Tg2576 Transgenic Mouse Model of Alzheimer's Disease

    If a similar decline occurs in human plasma, measurement of plasma Aβ may be useful as a premorbid biomarker for AD.

    “If a similar decline occurs in human plasma, it is possible that measurement of plasma A␤ may be useful as a premorbid biomarker for AD.”
    Quote in the paperSubstantial claim

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

    Premisecitation

    Aβ is the principal protein in the senile plaques of Alzheimer's disease.

    “Amyloid ␤ protein (A␤), the principal protein in the senile plaques of Alzheimer's disease (AD), is an ϳ4 kDa secreted polypeptide”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Glenner and Wong, 1984 source
    • cites Masters et al., 1985 source
    • cites Kang et al., 1987 source

  • Classified as probably not a substantial claim.

    Premisecitation

    Both SDS-dissociable and -insoluble forms of Aβ accumulate in human cortex.

    “They report that both SDSdissociable and -insoluble forms of A␤ accumulate in human cortex”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Funato et al., 1998

  • Classified as probably not a substantial claim.

    Premisecitation

    From studies of trisomy 21 brains, it is generally believed that, in human AD, Aβ deposition begins with the formation of diffuse plaques.

    “From studies of trisomy 21 brains (Iwatsubo et al., 1994), it is generally believed that, in human AD, A␤ deposition begins with the formation of diffuse plaques.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Iwatsubo et al., 1994 source

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

    Premisecitation

    The Swedish mutation causes concomitant increases in secreted Aβ42 and Aβ40.

    “It is well established that this mutation causes concomitant increases in secreted A␤42 and A␤40 (Cai et al., 1993;Citron et al., 1994;Scheuner et al., 1996).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Cai et al., 1993 source
    • cites Citron et al., 1994 source
    • cites Scheuner et al., 1996 source

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

    Interpretationreasoning

    In all of these genetic forms of Alzheimer's disease, Aβ metabolism is altered in a way that fosters Aβ aggregation and deposition.

    “Thus, in all of these genetic forms of AD, A␤ metabolism is altered in a way that fosters A␤ aggregation and deposition.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Tg2576 mice develop age-dependent behavioral deficits as assessed by Y maze, T maze, and Morris water maze testing.

    “In addition, Tg2576 mice develop agedependent behavioral deficits as assessed by Y maze, T maze, and Morris water maze testing (Hsiao et al., 1996;Chapman et al., 1999;Westerman et al., 2000).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Hsiao et al., 1996 source
    • cites Chapman et al., 1999 source
    • cites Westerman et al., 2000

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

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

    Study design and conductnone given

    Sections from seven AD brains were stained in parallel.

    “Sections from seven AD brains were stained in parallel.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Each genetic form of Alzheimer's disease either selectively increases the extracellular concentration of Aβ42 or increases both Aβ42 and Aβ40.

    “each of these genetic forms of AD either selectively increases the extracellular concentration of A␤42 (Suzuki et al., 1994;Borchelt et al., 1996;Duff et al., 1996;Scheuner et al., 1996;Citron et al., 1997) or increases both A␤42 and A␤40 (Cai et al., 1993;Citron et al., 1994;Scheuner et al., 1996).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Suzuki et al., 1994 source
    • cites Borchelt et al., 1996 source
    • cites Citron et al., 1997 source

  • Classified as probably not a substantial claim.

    Premisecitation

    Much of the Aβ deposited as amyloid in AD brain is resistant to SDS extraction and requires formic acid for solubilization.

    “It is well established that much of the A␤ deposited as amyloid in AD brain is resistant to SDS extraction and requires formic acid for solubilization (Roher et al., 1993).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Roher et al., 1993 source

  • May combine two claims.

    Premisecitation

    CSF Aβ has a high concentration relative to plasma Aβ and is normally cleared into blood.

    “because CSF A␤, which has a high concentration relative to plasma A␤, is normally cleared into blood (Ghersi-Egea et al., 1996).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Ghersi-Egea et al., 1996 source

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

    Premisecitation

    Secreted Aβ is readily detected in CSF, plasma, and medium conditioned by a wide variety of cultured cells.

    “Secreted A␤ is readily detected in CSF, plasma, and in medium conditioned by a wide variety of cultured cells”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Cai et al., 1993 source
    • cites Citron et al., 1994 source
    • cites Suzuki et al., 1994 source

  • Classified as probably not a substantial claim.

    Premisecitation

    It is well established that Aβ42 declines in the CSF of patients with typical late onset AD.

    “It is well established that A␤42 declines in the CSF of patients with typical late onset AD (Motter et al., 1995;Nitsch et al., 1995;Kanai et al., 1998;Andreasen et al., 1999)”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Motter et al., 1995 source
    • cites Nitsch et al., 1995 source
    • cites Kanai et al., 1998 source

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

    Premisecitation

    Aβ1-42 is deposited early and selectively in senile plaques.

    “there is good evidence that A␤1-42 is deposited early and selectively in senile plaques (Iwatsubo et al., 1994).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Iwatsubo et al., 1994 source

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

    Premisecitation

    Synthetic Aβ1-42 forms amyloid fibrils in vitro much more readily than Aβ1-40.

    “Synthetic A␤1-42 forms amyloid fibrils in vitro much more readily than A␤1-40 (Jarrett et al., 1993)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Jarrett et al., 1993 source

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Nontransgenic tissues were processed identically in parallel with the transgenic tissues.

    “Nontransgenic tissues were processed identically in parallel with the transgenic tissues.”
    Quote in the paperSubstantial claim

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

    Premisecitation

    Early onset Alzheimer's disease can be caused by mutations in the APP, presenilin 1, and presenilin 2 genes.

    “Early onset Alzheimer's disease can be caused by mutations in the APP (Chartier-Harlin et al., 1991;Goate et al., 1991;Murrell et al., 1991;Mullan et al., 1992), presenilin 1 (PS1) (Sherrington et al., 1995), and presenilin 2 (PS2) (Levy-Lahad et al., 1995) genes.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Chartier-Harlin et al., 1991 source
    • cites Goate et al., 1991 source
    • cites Sherrington et al., 1995 source

  • Classified as probably not a substantial claim.

    Premisecitation

    Immunodetection of Aβ in human cortex requires 400 pmol/gm insoluble Aβ42 (or 200 pmol/gm in hippocampus).

    “They calculate that immunodetection of A␤ in human cortex requires 400 pmol/gm insoluble A␤42 (or 200 pmol/gm in hippocampus) (Funato et al., 1998).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Funato et al., 1998

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    In a previous study of human plasma, the Swedish APP K670N,M671L mutation increases both Aβ42 and Aβ40 and other FAD-linked APP, PS1, and PS2 mutations selectively increase Aβ42.

    “In a previous study of human plasma (Scheuner et al., 1996), we showed that the Swedish APP K670N,M671L mutation increases both A␤42 and A␤40 and that other FAD-linked APP, PS1, and PS2 mutations selectively increase A␤42.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Scheuner et al., 1996 source

  • Classified as probably not a substantial claim.

    Premisecitation

    Biochemical detection of Aβ precedes plaque formation in human cortex.

    “and that its biochemical detection precedes plaque formation.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Funato et al., 1998

  • Classified as probably not a substantial claim.

    Premisecitation

    These modifications of Aβ are thought to be important for amyloid deposition.

    “these modifications of A␤ are thought to be important for amyloid deposition.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Saido et al., 1996 source
    • cites Kuo et al., 1998 source

  • May combine two claims.

    Premisecitation

    Human plasma Aβ42 and Aβ40 increase with aging over age 65 and are heritable traits that are increased in first degree relatives of patients with typical late onset AD.

    “We have shown recently that human plasma A␤42 and A␤40 increase with aging over age 65 and that plasma A␤42 and A␤40 are heritable traits that are increased in first degree relatives of patients with typical late onset AD (Younkin et al., 1998).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Younkin et al., 1998

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

  • Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing).

    Interpretationreasoning

    One way to account for these negative results is to postulate that plasma Aβ42 also declines as AD develops.

    “Because it is well established that CSF A␤42 decreases in AD, one way to account for these negative results is to postulate that plasma A␤42 also declines as AD develops.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    Insoluble Aβ correlates with amyloid load in human cortex.

    “that insoluble A␤ correlates with amyloid load”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Funato et al., 1998

  • May combine two claims.

    Interpretationreasoning

    In Tg2576 mice as in human subjects, plasma Aβ is likely to be derived from both peripheral organs and brain, where Aβ may enter the bloodstream either through the normal flow of CSF or by directly crossing CNS endothelium.

    “Thus, in Tg2576 mice as in human subjects, plasma A␤ is likely to be derived from both peripheral organs and brain, where A␤ may enter the bloodstream either through the normal flow of CSF or by directly crossing CNS endothelium.”
    Quote in the paperSubstantial claim

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

    Interpretationreasoning

    Elevated plasma Aβ could be an excellent premorbid biomarker for AD, although it is not useful as a diagnostic marker, if it identifies those who are destined to deposit Aβ and those who are in the early stages of deposition.

    “Similarly, elevated plasma A␤ could be an excellent premorbid biomarker for AD, although it is not useful as a diagnostic marker, if it identifies those who are destined to deposit A␤ and those who are in the early stages of deposition.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationown data

    If declining plasma Aβ also occurs in human subjects, then declining plasma Aβ could be a useful marker for subjects in whom there is cerebral Aβ deposition and who are, therefore, at risk for AD.

    “If this also occurs in human subjects, then declining plasma A␤ could be a useful marker for subjects in whom there is cerebral A␤ deposition and who are, therefore, at risk for AD.”
    Quote in the paperSubstantial claim

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

    Premisecitation

    Cerebral Aβ deposition in FAD occurs because of an increase in CNS Aβ that develops as part of a generalized genetic effect that also increases plasma Aβ.

    “In that report, we suggested that cerebral A␤ deposition in FAD occurs because of an increase in CNS A␤ that develops as part of a generalized genetic effect that also increases plasma A␤.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Scheuner et al., 1996 source

  • May combine two claims.

    Premisecitation

    N-terminally truncated or modified Aβ [especially forms beginning with pyroglutamate at position 3 (3pE)] and oligomers are resistant to proteolysis.

    “Because N-terminally truncated or modified A␤ [especially forms beginning with pyroglutamate at position 3 (3pE)] and oligomers are resistant to proteolysis (Saido et al., 1996;Kuo et al., 1998)”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Saido et al., 1996 source
    • cites Kuo et al., 1998 source

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    If plasma Aβ42 declines as AD develops, then analysis of symptomatic late onset patients could miss many patients whose disease was initiated by increased Aβ in the presymptomatic period.

    “If so, then analysis of symptomatic late onset patients could miss many patients whose disease was initiated by increased A␤ in the presymptomatic period.”
    Quote in the paperSubstantial claim
68 of 68

  • The paper relies on this without support.

    The human AD brain samples used for comparison are representative of Alzheimer's disease brain pathology.

    “Sections from seven AD brains were stained in parallel.”

  • The paper relies on this without support.

    N-terminal modifications or truncations of Aβ make Aβ more insoluble in human brain.

    “which are thought to make A␤ more insoluble in human brain”

  • The paper relies on this without support.

    The Tg2576 transgenic mouse model is a valid model for studying human AD Aβ deposition.

    “To determine whether CSF and plasma A␤ decline in Tg2576 mice as A␤42 and A␤40 are deposited in the brain, we analyzed brain (Fig. 7 A, B), CSF (Fig. 7C, D), and plasma (Fig. 7 E, F ) A␤42 and A␤40 in parallel.”
3 of 3

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?

  • Tg2576 mice exhibit elevated Aβ from 2 months old onward, plaques after 6 months old, and cognitive deficits beginning at 5 months old.

    “Tg2576 mice exhibit elevated Aβ from 2 months old onward, plaques after 6 months old, and cognitive deficits beginning at 5 months old [32,33,34].”

    From VEEV TC-83 Triggers Dysregulation of the Tryptophan–Kynurenine Pathway in the Central Nervous System That Correlates with Cognitive Impairment in Tg2576 Mice (2024) · cites this paper as [32]

    The section “Cored plaques appear early in Tg2576 brain” (page unavailable) reports cored plaques at 7–8 months, supporting plaques after 6 months. The Discussion (page unavailable) places the onset of insoluble Aβ changes at 6–7 months, not 2 months; the introduction mentions age-dependent behavioral deficits but gives no 5-month onset. Thus the cited paper does not support the two specific early ages in the claim. (LLM, conf=0.87)

    Experimental — accuracy not yet measured

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.

  • Aβx-42 is reported below the full-length Aβ1-42 it includes

    Minor

    Table 2 reports 1,379 pmol/gm of Tg2576 Aβx-42 but 3,409 pmol/gm of Aβ1-42 in the same fraction. The paper says the assay for Aβx-42 detects full-length as well as N-terminally modified or truncated Aβ, so its reported amount cannot be lower than the full-length amount.

  • Conflicting p-values for the CSF Aβ42 decline

    Minor

    The Results report p = 0.03 for the decline in CSF Aβ42, whereas the Figure 7 caption reports p = 0.02 for the same decline.

2 of 2

Cites

Flagged first, then by citations

Research works printed but not linked: 2

  1. Westerman, 2000, Age-dependent behavioral deficit in a transgenic mouse model of Alzheimer's disease., Soc Neurosci Abstr, 26, 1318
  2. Younkin, 1998, Genetic elevation of plasma amyloid β protein in typical late onset Alzheimer's disease., Soc Neurosci Abstr, 24, 263

Cited by

Sorted by citations

Related

Authors
Kawarabayashi, T., Younkin, L. H., Saido, T. C., Shoji, M., Ashe, K. H., & Younkin, S. G.
Affiliations
  • Mayo Clinic (US)
  • Mayo Clinic in Florida (US)
  • RIKEN (JP)
  • Gunma University (JP)
  • University of Minnesota (US)
ORCID
Venue
The Journal of Neuroscience
Publisher
Society for Neuroscience
Published
2001-01-15
Volume
21
Issue
2
Pages
372-381
ISSN
  • 0270-6474 (ISSN-L)
  • 1529-2401
DOI
10.1523/jneurosci.21-02-00372.2001
PMC
PMC6763819
OpenAlex
W1929267935
Semantic Scholar
3ed4c46400edeece515c7a23e469e89c233699f5
Cited by
1,053
References
38
Citations by year
2026: 14 · 2025: 23 · 2024: 31 · 2023: 22 · 2022: 33 · 2021: 27 · 2020: 28 · 2019: 24 · 2018: 21 · 2017: 39 · 2016: 45 · 2015: 41 · 2014: 56 · 2013: 64 · 2012: 71
FWCI
29.08
Type
journal article
Language
en
Open access
Licence
Locations
  • Journal of Neuroscience (publishedVersion, cc-by-nc-sa)
  • PubMed (publishedVersion)
  • PubMed Central (submittedVersion)
Funders
  • National Institutes of Health
  • National Institute on Aging (P01 AG015453, AG 15453)
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 oligomers, amyloid plaques, neuritic plaques, cerebrospinal fluid amyloid, biomarkers, amyloid-beta 42, Aβ40
MeSH terms
Aging, Alzheimer Disease, Animals, Brain, Brain Chemistry, Disease Models, Animal, Enzyme-Linked Immunosorbent Assay, Female, Formates, Humans, Immunohistochemistry, Male, Mice, Inbred C57BL, Mice, Transgenic, Organ Specificity, Sodium Dodecyl Sulfate, Immunoblotting, Biomarkers, Amyloid beta-Peptides, Amyloid beta-Protein Precursor, Mice, Plaque, Amyloid

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-27.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-27.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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