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Cited by 682Barrier Structure and Function StudiesAlzheimer's disease research and treatmentsNeuroinflammation and Neurodegeneration Mechanisms

Amyloid β oligomers constrict human capillaries in Alzheimer's disease via signaling to pericytes

Open access
Nortley, Ross, Korte, Nils, Izquierdo, Pablo, Hirunpattarasilp, Chanawee, Mishra, Anusha, Jaunmuktane, Zane, Kyrargyri, Vasiliki, Pfeiffer, Thomas +10 more·2019·Science
DOI 10.1126/science.aav9518PMC PMC6658218

Published version of a preprint

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Abstract

Pericytes put the squeeze on cognition: Like a computer, the brain needs a reliable source of power, which is provided as oxygen and glucose in the blood. However, in many neurological disorders this energy supply is disrupted. Brain blood flow is controlled by adjustment of the diameters of the vessels supplying the blood. Nortley et al. found that, both in humans developing Alzheimer's disease (AD) and in a mouse model of AD, brain capillaries become squeezed by pericytes (see the Perspective by Liesz). By defining the underlying mechanism, they suggest potential targets for therapy in early AD. Science , this issue p. eaav9518 ; see also p. 223

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Written from the paper’s full text.

TL;DR

Amyloid β oligomers constrict human and rodent brain capillaries at pericyte locations via reactive oxygen species, endothelin-1, and pericyte ETA receptors. In human cognitive-decline biopsies and an AD mouse model, this pericyte-mediated capillary constriction is predicted to substantially reduce cerebral blood flow and can be reversed by C-type natriuretic peptide.

Key findings

  • Soluble Aβ1–42 constricted all 4 human capillaries tested by ~25% after 40 min (p=0.01); in rat slices, 16/20 capillaries (80%) constricted >5%, reaching ~15% after 1 h (p=0.006), with an apparent EC50 of 4.7 nM.
  • The Aβ-evoked constriction was blocked by ETA receptor blocker BQ-123 (p=0.008), SOD1 (p=3.7×10⁻⁶), NADPH oxidase inhibitor DPI (p=0.032), and NOX4 blocker GKT137831 (p=0.0011); NOX2 blocker ebselen reduced it by only 45%. Aβ increased ROS in pericytes 7.28-fold (p=0.001) versus 1.76-fold in Iba1-expressing immune cells (p=0.05), giving 6.4-fold more total ROS generation by pericytes.
  • In rapidly fixed biopsies from 13 living patients with cognitive decline, 7 had Aβ deposition and 6 did not. Mean capillary diameter was 8.1% smaller with Aβ deposition (p=0.0007); near pericyte somata, diameter was ~25% larger in no-Aβ patients (p=3.7×10⁻⁷) but ~30% smaller in Aβ-deposition patients (p=1.6×10⁻²⁰), predicted to reduce flow by ~50% (Discussion; Methods calculation gives 58%).
  • In APPNL-G-F AD mice in vivo, capillary diameter was smaller (p=1.7×10⁻⁹) and more strongly reduced at pericyte somata (p=1.6×10⁻¹⁷), while arterioles and venules were not constricted; cerebellar capillaries showed no constriction. CNP (100 nM) reversed Aβ-evoked capillary constriction (p=0.029), whereas combined NOX4 + ETA blockade prevented further constriction (p=0.027) but did not reverse diameter to baseline within 1 h.

Methods

  • Live human cortical slices from neurosurgical tumour-access tissue, rapidly fixed human cortical biopsies from patients with cognitive decline, rat cortical slices, and APPNL-G-F × NG2-DsRed mice were used; methods included immunohistochemistry, two-photon imaging, pericyte Ca²⁺ imaging, ROS/GSH imaging, propidium iodide death assays, and pimonidazole hypoxia labelling.
  • Capillary diameters were measured blinded to Aβ status, often as a function of distance from PDGFRβ-labelled pericyte somata; analyses used t-tests, Mann-Whitney tests, linear regression slopes, and Holm-Bonferroni correction.
  • Flow effects were estimated from Poiseuille’s law, assuming pericytes spaced at 2L and capillary constriction near somata.

Limitations

  • Stated: limited live human tissue precluded detailed mechanistic analysis; the authors cannot rule out that ETA receptors are on a different cell type; the Aβ deposition measure may largely reflect plaques; GSH changes cannot be converted to ROS synthesis rates; future work is needed on ageing humans who accumulate Aβ without AD and on ET receptor affinity in AD mice.
  • Evident from the text: human biopsy data come from a small cohort (13 patients; subgroups of 6 no Aβ, 3 moderate, 4 severe), live human slice data are very limited (94 pericytes from 2 patients; 4 capillaries for Aβ), most mechanistic work is in rat slices, and the in vivo AD mouse data are from ~4-month-old mice.

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Integrity signals

Registry

Crossref · 10.1126/science.aav9518

Cites

53 of 53 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 37 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    36% of pericytes labeled for α smooth muscle actin.

    “the processes of 36% of pericytes labeled for α smooth muscle actin (Fig. 1D)”
    Quote in the paperSubstantial claim
  • Findingown data

    Applying soluble Aβ1−42 (oligomeric + monomeric, 72 nM) to human brain slices evoked a slowly developing constriction of all 4 capillaries tested, reducing diameter by ~25% after 40 minutes.

    “Applying soluble Aβ1−42 (oligomeric + monomeric, 72 nM calculated from the monomeric MW) to human brain slices evoked a slowly developing constriction of all 4 capillaries tested, which reduced their diameter by ~25% after 40 mins (Fig. 1H, significantly reduced, p=0.01).”
    Quote in the paperSubstantial claim
  • Findingown data

    Aβ1−42 evoked constriction of rat capillaries near pericyte locations.

    “Aβ1−42 evoked a constriction of rat capillaries near pericyte locations”
    Quote in the paperSubstantial claim
  • Findingown data

    Hypoxic tissue labeling by pimonidazole was increased significantly in vivo in the AD mice.

    “hypoxic tissue labeling by pimonidazole (hypoxyprobe) was increased significantly in vivo in the AD mice (Fig. S7).”
    Quote in the paperSubstantial claim
  • Findingown data

    In AD mice, the diameter at pericyte somata was more strongly reduced than in wild-type mice.

    “and the diameter at pericyte somata was more strongly reduced (Fig. 5E, p=1.6x10-17).”
    Quote in the paperSubstantial claim
  • May combine two claims. 24
  • Classified as probably not a substantial claim. 32

  • May combine two claims.

    Findingcitation

    The mean distance between human pericytes was 65.3±0.4 μm (94 pericytes from 2 patients), 30% larger than in rodents.

    “The mean distance between human pericytes was 65.3±0.4 μm (for 94 pericytes imaged in tissue from 2 patients), 30% larger than in rodents (19).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [19] Hall CN Reynell C Gesslein B Hamilton NB Mishra A Sutherland BA O’Farrell FM Buchan AM Lauritzen M Attwell D Capillary pericytes regulate cerebral blood flow in health and disease Nature 2014 508 55 60 24670647 PMC3976267 source

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    In human brain slices, superfused noradrenaline constricted and glutamate dilated capillaries at pericyte locations.

    “superfused noradrenaline constricted and glutamate dilated the capillaries at pericyte locations (Fig. 1E, F).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Capillaries monitored without Aβ or with scrambled Aβ1−42 showed no significant diameter change.

    “Capillaries monitored for an hour without applying Aβ, or those to which a version of Aβ1−42 with a scrambled sequence was applied (prepared as for the Aβ oligomers), showed no significant diameter change (Fig. 2C, G).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Aβ1−42 (72 nM, applied for 40 minutes) evoked an increase in ROS level that was suppressed by SOD1.

    “Aβ1−42 (72 nM, applied for 40 mins) evoked an increase in ROS level that was suppressed by the presence of SOD1 (Fig. 3A, B).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Aβ increased ROS production in pericytes by a factor of 7.28 and in immune (Iba1-expressing) cells by a factor of 1.76.

    “Aβ increased ROS production in pericytes by a factor of 7.28 (p=0.001) and in immune (Iba1-expressing) cells by a factor of 1.76 (p=0.05).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Combined block of NOX4 (GKT137831) and ETA receptor (BQ-123) prevented further constriction evoked by Aβ but did not reverse capillary diameter to baseline on a 1 hour time scale.

    “This prevented further constriction evoked by Aβ(p=0.027), but did not reverse the capillary diameter to its baseline value on a 1 hour time scale (Fig. 6A).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    ET-evoked constriction was blocked by the ETA blocker BQ-123 but not by the ETB blocker BQ-788.

    “which was blocked by the ETA blocker BQ-123 (1 μM, p=2.6x10-11), but not by the ETB blocker BQ-788 (1 μM, p=0.91, Fig. 2H).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Aβ (72 nM for 40 minutes) reduced the GSH level in pericytes by 20% and in microglia by 55%.

    “Aβ (72 nM for 40 mins) reduced the GSH level in pericytes by 20% and in microglia by 55% (Fig. S4, p=0.014 and p=2x10-29 respectively).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In cerebellum, both wild-type and AD mice showed a larger capillary diameter near pericyte somata, with no evidence for a constriction in the AD mice.

    “In cerebellum, both WT and AD mice (n=3 each) showed a larger capillary diameter near pericyte somata (Fig. 5G, p=0.002), with no evidence for a constriction in the AD mice.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In pericytes expressing GCaMP5G, applying ET (10 nM) evoked a rise in [Ca2+]i while aCSF had no effect.

    “applying ET (10 nM) evoked a rise in [Ca2+]i while aCSF had no effect (Fig. 2K-L).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Applying BQ-123, SOD1, or DPI alone did not affect capillary diameter.

    “In contrast, applying these agents alone did not affect capillary diameter (changes after 1 hour were: BQ-123, -0.7±5.2%, n=13, p=0.9; SOD1, 3.4±5.8%, n=9, p=0.57; DPI, -7.4±3.2%, n=5, p=0.082).”
    Quote in the paperSubstantial claim

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

    Findingnone given

    It was not possible to make pure monomeric preparations of Aβ1-42 or Aβ1-40.

    “It was not possible to make pure monomeric preparations of Aβ1-42 or Aβ1-40.”
    Quote in the paperNot a substantial claim

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

    Findingcitation

    In human brain slices, healthy capillaries have mean diameter 5.08±0.33 μm (n=12).

    “Healthy capillaries (<10 μm in diameter, mean diameter 5.61±0.03 μm (n=299) in rat, and 5.08±0.33 μm (n=12) in human, with no rings of arteriolar smooth muscle around them) were selected as previously described (41)”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Aβ1-42 and Aβ1-40 formed monomers and oligomers, while scrambled Aβ1-42 formed mainly monomers.

    “Aβ1-42 and Aβ1-40 formed monomers and oligomers, while scrambled Aβ1-42 formed mainly monomers (Fig. 1G).”
    Quote in the paperSubstantial claim

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

    Findingcitation

    In rat brain slices, healthy capillaries (<10 μm diameter) have mean diameter 5.61±0.03 μm (n=299).

    “Healthy capillaries (<10 μm in diameter, mean diameter 5.61±0.03 μm (n=299) in rat, and 5.08±0.33 μm (n=12) in human, with no rings of arteriolar smooth muscle around them) were selected as previously described (41)”
    Quote in the paperNot a substantial claim

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

    Findingown data

    The mean age of patients without Aβ deposition was 50.5±5.5 (n=6, 4 women and 2 men), and of those with Aβ deposition was 62.1±4.2 (n=7, 4 women and 3 men), not significantly different (p=0.11).

    “The mean age of patients without Aβ deposition was 50.5±5.5 (n=6, 4 women and 2 men), and of those with Aβ deposition was 62.1±4.2 (n=7, 4 women and 3 men, not significantly different, p=0.11).”
    Quote in the paperNot a substantial claim

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

    Findingown data

    Mice aged ~4 months (P119-P143) were not significantly different for WT and AD (p=0.13).

    “Mice aged ~4 months (P119-P143, not significantly different for WT and AD, p=0.13) were anesthetised using urethane (1.55 g/kg given in two doses 15 minutes apart).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Regressing mean capillary diameter against age from all patients, or from patients lacking Aβ deposition, showed no significant dependence on age (p=0.5 and p=0.82 respectively).

    “Regressing mean capillary diameter against age from all patients, or from the patients lacking Aβ deposition, showed that there was no significant dependence on age (p=0.5 and p=0.82 respectively).”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Cerebral blood flow in the grey matter can be reduced by over 40% in Alzheimer's disease.

    “Cerebral blood flow in the grey matter can be reduced by over 40% (3)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [3] Asllani I Habeck C Scarmeas N Borogovac A Brown TR Stern Y Multivariate and univariate analysis of continuous arterial spin labeling perfusion MRI in Alzheimer's disease J Cereb Blood Flow Metab 2008 28 725 736 17960142 PMC2711077 source

      Not checked in the free run.

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

    Premisecitation

    Reduced blood flow increases Aβ production.

    “reduced blood flow increases Aβ production (13, 14).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [13] Sun X He G Qing H Zhou W Dobie F Cai F Staufenbiel M Huang LE Song W Hypoxia facilitates Alzheimer’s disease pathogenesis by up-regulating BACE1 gene expression Proc Natl Acad Sci USA 2006 103 18727 18732 17121991 PMC1693730 source

      Not checked in the free run.

    • cites [14] Zhang X Zhou K Wang R Cui J Lipton SA Liao FF Xu H Zhang YW Hypoxia-inducible factor 1α(HIF-1α)-mediated hypoxia increases BACE1 expression and β-amyloid generation J Biol Chem 2007 282 10873 10880 17303576 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    A subset of pericytes on capillary walls is contractile, and these are the only contractile cells on capillaries.

    “A subset of pericytes on capillary walls is contractile (these are the only contractile cells on capillaries (18))”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [18] Peppiatt CM Howarth C Mobbs PG Attwell D Bidirectional control of CNS capillary diameter by pericytes Nature 2006 443 700 704 17036005 PMC1761848 source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Aβ1−42 oligomers are the molecular species believed to be responsible for Aβ's toxic effects in Alzheimer's disease.

    “Aβ1−42 oligomers, the molecular species believed to be responsible for Aβ’s toxic effects in AD (22, 23).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [22] Klein WL Krafft GA Finch CE Targeting small Aβ oligomers: the solution to an Alzheimer’s disease conundrum? Trends Neurosci 2001 24 219 224 11250006

      Not checked in the free run.

    • cites [23] Attems J Lintner F Jellinger KA Amyloid β peptide 1-42 highly correlates with capillary cerebral amyloid angiopathy and Alzheimer disease pathology Acta Neuropathol 2004 107 283 291 14986026

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Exogenous amyloid β can reduce cerebral blood flow.

    “Exogenous amyloid β can reduce cerebral blood flow (10–12)”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [10] Suo Z Humphrey J Kundtz A Sethi F Placzek A Crawford F Mullan M Soluble Alzheimer’s β-amyloid constricts the cerebral vasculature in vivo Neurosci Lett 1998 257 77 80 9865931

      Not checked in the free run.

    • cites [11] Deane R Du Yan S Submamaryan RK LaRue B Jovanovic S Hogg E Welch D Manness L Lin C Yu J Zhu H RAGE mediates amyloid-beta peptide transport across the blood-brain barrier and accumulation in brain Nat Med 2003 9 907 913 12808450 source

      Not checked in the free run.

    • cites [12] Dietrich HH Xiang C Han BH Zipfel GJ Holtzman DM Soluble amyloid-beta, effect on cerebral arteriolar regulation and vascular cells Molec Neurodegen 2010 5 15 PMC2873254 20388225

      Not checked in the free run.

  • May combine two claims.

    Interpretationown data

    The cells showing the brightest oxidized dihydroethidium fluorescence were located on capillaries, had pericyte morphology, and labeled for NG2 but not Iba1, implying they are pericytes.

    “the cells showing the brightest oxidised dihydroethidium fluorescence were located on capillaries, had the morphology of pericytes, and labeled for NG2 but not Iba1 (Fig. 3C), implying that they are pericytes.”
    Quote in the paperSubstantial claim

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

    Study design and conductown data

    Analysis of ROS production was performed using the z-stack as the statistical unit.

    “For each z-stack, a mean intensity per pericyte or Iba-1-labeled cell, and the total intensity per population of pericytes or Iba1-labeled cells, were calculated, and analysis was performed using the z-stack as the statistical unit.”
    Quote in the paperNot a substantial claim

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

    Study design and conductnone given

    The work on fresh living human brain tissue received ethical approval and all patients gave informed consent.

    “The work on fresh living human brain tissue received ethical approval from the National Health Service (REC number 15/NW/0568) and all patients gave informed consent.”
    Quote in the paperSubstantial claim

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

    Premisecitation

    Dihydroethidium oxidation to ethidium is specific to O2.- and binds to DNA and RNA of O2.-producing cells.

    “Cellular production of reactive oxygen species (ROS) in brain slices was visualised through the O2.-specific oxidation of dihydroethidium to ethidium, which binds to the DNA and RNA of O2.-producing cells (46).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [46] Wu L-J Wu G Akhavan Sharif MR Baker A Jia Y Fahey FH Luo HR Feener EP Clapham DE The voltage-gated proton channel, Hv1, enhances brain damage from ischemic stroke Nat Neurosci 2012 15 565 573 22388960 PMC3314139 source

      Not checked in the free run.

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

    Premisecitation

    C-type natriuretic peptide can reverse ET-mediated effects by blocking Ca2+ release from internal stores and activating myosin light chain phosphatase.

    “C-type natriuretic peptide (CNP), which can reverse ET-mediated effects (36) by blocking Ca2+ release from internal stores and activating myosin light chain phosphatase (Fig. S8).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [36] Špiranec K Chen W Werner F Nikolaev VO Naruke T Koch F Werner A Eder-Negrin P Diéguez-Hurtado R Adams RH Baba HA Endothelial C-type natriuretic peptide acts on pericytes to regulate microcirculatory flow and blood pressure Circulation 2018 138 494 508 29626067 source

      Not checked in the free run.

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

    Premisecitation

    Isolectin B4 binds to α-D-galactose residues in the basement membrane generated by pericytes and endothelial cells, and outlines pericytes.

    “In some experiments pericytes were identified prior to imaging by incubating slices for 30 min in 10 μg/ml isolectin B4 conjugated to Alexa 488 or 568 (ThermoFisher I21411 or 121412), which binds to α-D-galactose residues in the basement membrane generated by pericytes and endothelial cells, and outlines pericytes (41).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [41] Mishra A O’Farrell FM Reynall C Hamilton NB Hall CN Attwell D Imaging pericytes and capillary diameter in brain slices and isolated retinae Nat Protoc 2014 9 323 336 24434801

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductown data

    Pericytes were identified by morphology confirmed by isolectin B4 labelling, PDGFRβ antibody labelling, or NG2 promoter-driven dsRed expression.

    “Throughout this work pericytes were identified by their morphology (spatially isolated cells located outside capillaries) as confirmed by isolectin B4 labelling, or by antibody labelling for their characteristic marker PDGFRβ, or by expression of dsRed under the NG2 promoter.”
    Quote in the paperSubstantial claim

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

    Study design and conductown data

    The experimenter was blinded to the occurrence of Aβ deposition when measuring capillary density and diameter.

    “with the experimenter blinded to the occurrence of Aβ deposition (viewing only the PDGFRβ image channel)”
    Quote in the paperNot a substantial claim

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

    Study design and conductown data

    Oligodendrocyte precursor cells and arteriolar smooth muscle cells were excluded from the analysis of pericyte Ca2+ imaging.

    “Oligodendrocyte precursor cells (OPCs), identified based on a star-like morphology and weaker baseline fluorescence, and arteriolar smooth muscle cells, were excluded from the analysis.”
    Quote in the paperNot a substantial claim

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

    Study design and conductreasoning

    No preincubation with DHE was used, to limit the intracellular accumulation of oxidised product.

    “No preincubation with DHE was used, to limit the intracellular accumulation of oxidised product.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Capillary diameter was measured by an analyst blinded to the time and identity of drug application.

    “Capillary diameter was measured from the resulting movies, by an analyst blinded to the time and identity of drug application, by placing a line across the lumen on magnified images using Metamorph software.”
    Quote in the paperSubstantial claim

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

    Study design and conductown data

    Pericyte responses to noradrenaline and glutamate were observed whether or not there was tumour infiltration.

    “Pericyte responses to noradrenaline and glutamate as documented in Fig. 1 were observed whether or not there was tumour infiltration.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    Quantification of the percentage of pericytes that were dead excluded cells within 20 μm of the slice surface to avoid counting cells killed by the slicing procedure.

    “To avoid counting cells killed by the slicing procedure, quantification of the percentage of pericytes that were dead excluded cells within 20 μm of the slice surface.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Aβ was only applied to human slices that showed no tumour infiltration.

    “Aβ was only applied to slices that showed no tumour infiltration.”
    Quote in the paperSubstantial claim

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

    Interpretationcitation

    Capillary constriction by pericytes may explain why some capillaries become occluded by neutrophils in Alzheimer's disease.

    “Capillary constriction by pericytes may explain why some capillaries become occluded by neutrophils in AD (37)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [37] Roberts BR Lind M Wagen AZ Rembach A Frugier T Li QX Ryan TM McLean CA Doecke JD Rowe CC Villemagne VL Biochemically-defined pools of amyloid-β in sporadic Alzheimer’s disease: correlation with amyloid PET Brain 2017 140 1486 1498 28383676

      Not checked in the free run.

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

    Study design and conductnone given

    Adequate anesthesia was ensured by confirming the absence of a withdrawal response to a paw pinch.

    “Adequate anesthesia was ensured by confirming the absence of a withdrawal response to a paw pinch.”
    Quote in the paperNot a substantial claim

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

    Study design and conductnone given

    Data normality was assessed with Shapiro-Wilk or D'Agostino-Pearson omnibus tests.

    “Data normality was assessed with Shapiro-Wilk or D'Agostino-Pearson omnibus tests.”
    Quote in the paperNot a substantial claim

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

    Study design and conductnone given

    P values were corrected for multiple comparisons using a procedure equivalent to the Holm-Bonferroni method.

    “P values were corrected for multiple comparisons using a procedure equivalent to the Holm-Bonferroni method (for N comparisons, the most significant p value is multiplied by N, the 2nd most significant by N-1, the 3rd most significant by N-2, etc.; corrected p values are significant if they are less than 0.05).”
    Quote in the paperNot a substantial claim

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

    Study design and conductreasoning

    The dura was left intact, to reduce perturbation of the brain.

    “The dura was left intact, to reduce perturbation of the brain.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    AD mice have APP with a humanised Aβ region containing 3 AD-related mutations (APPNL-G-F) knocked in, to avoid artefacts associated with over-expressing APP.

    “AD mice, in which APP with a humanised Aβ region containing 3 AD-related mutations (APPNL-G-F) is knocked in (49), to avoid artefacts associated with over-expressing APP, were crossed with NG2-DsRed mice in which pericytes express DsRed (19).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [49] Saito T Matsuba Y Mihira N Takano J Nilsson P Itohara S Iwata N Saido TC Single App knock-in mouse models of Alzheimer's disease Nat Neurosci 2014 1 661 663 24728269 source

      Not checked in the free run.

    • cites [19] Hall CN Reynell C Gesslein B Hamilton NB Mishra A Sutherland BA O’Farrell FM Buchan AM Lauritzen M Attwell D Capillary pericytes regulate cerebral blood flow in health and disease Nature 2014 508 55 60 24670647 PMC3976267 source

      Not checked in the free run.

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

    Premisecitation

    The GSH-NEM antibody is specific to the GSH-NEM adduct, allowing quantification of reduced glutathione after reaction with NEM.

    “The sections were additionally immunolabeled with a GSH-NEM antibody (Millipore MAB3194, 1:500) which is specific to this adduct, allowing quantification of reduced glutathione after reaction with NEM (47).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [47] Won SJ Kim JE Cittolin-Santos GF Swanson RA Assessment at the single-cell level identifies neuronal glutathione depletion as both a cause and effect of ischemia-reperfusion oxidative stress J Neurosci 2015 35 7143 7152 25948264 PMC4420782

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Although the measure of Aβ may largely reflect the presence of plaques, it is likely that the soluble Aβ concentration correlates with plaque load.

    “Although this measure of Aβ may largely reflect the presence of plaques, it is likely that the soluble Aβ concentration correlates with plaque load (48).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [48] Murphy MP Levine H III Alzheimer’s disease and the β-amyloid peptide J Alzheimer’s Dis 2010 19 311 323 20061647 PMC2813509

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductown data

    Images were analysed to assess capillary diameter with the experimenter blinded to the level of Aβ deposits.

    “Images were analysed to assess capillary diameter with the experimenter blinded to the level of Aβ deposits (i.e. viewing only the PDGFRβ channel: the condition of the tissue was sometimes worse for patients with Aβ deposition, but it was not possible to unambiguously decide whether the patient had Aβ deposition without viewing the Aβ channel).”
    Quote in the paperSubstantial claim

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

    Study design and conductcitation

    For a control response of 100%, a response standard deviation of 10%, a response in a drug of 70% (30% inhibition), a power of 80% and p<0.05, less than 6 vessels are needed in each of the control and drug groups.

    “An estimate of the sample size needed for a typical experiment is as follows: For a control response of 100%, a response standard deviation of 10%, a response in a drug of 70% (30% inhibition), a power of 80% and p<0.05, less than 6 vessels are needed in each of the control and drug groups (www.biomath.info/power/ttest.htm).”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    The contractility of capillary pericytes decreases for higher branching orders of capillary.

    “the contractility of capillary pericytes decreases for higher branching orders of capillary (19)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [19] Hall CN Reynell C Gesslein B Hamilton NB Mishra A Sutherland BA O’Farrell FM Buchan AM Lauritzen M Attwell D Capillary pericytes regulate cerebral blood flow in health and disease Nature 2014 508 55 60 24670647 PMC3976267 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    In reality the flow reduction could be greater than this because Poiseuille's law does not apply for small capillary diameters for which the effective blood viscosity increases as the diameter decreases below 10 μm.

    “In reality the flow reduction could be greater than this because Poiseuille’s law does not apply for small capillary diameters for which the effective blood viscosity increases as the diameter decreases below 10 μm (50).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [50] Pries AR Secomb TW Gaehtgens P Gross JF Blood flow in microvascular networks. Experiments and simulation Circ Res 1990 67 826 834 2208609

      Not checked in the free run.

49 of 49

  • The authors state this as an assumption.

    The ETA receptors involved in ET-evoked pericyte constriction are located on the pericytes themselves.

    “We assume that the ETA receptors involved are located on the pericytes themselves, since ET raised the [Ca2+]i in pericytes, but we cannot rule out the possibility that they are on a different cell type.”

  • The paper relies on this without support.

    The soluble Aβ concentration correlates with plaque load.

    “although this measure of Aβ may largely reflect the presence of plaques, it is likely that the soluble Aβ concentration correlates with plaque load”

  • The paper relies on this without support.

    In humans, the cerebellum is relatively spared of amyloid plaque pathology.

    “an area that is relatively spared of amyloid plaque pathology in humans”

  • The authors state this as an assumption.

    Pericytes are regularly spaced on capillaries at an interval of 2L.

    “We assume that pericytes are regularly spaced on capillaries at an interval of 2L.”

  • The authors state this as an assumption.

    Flow in capillaries is governed by Poiseuille's law.

    “For flow governed by Poiseuille’s law, the resistance of a segment of capillary of length L (from a pericyte soma to midway between two pericytes) and radius r1 is given by k.L/r14 where k is a constant.”

  • The authors state this as an assumption.

    The reduction in capillary diameter from the midpoint between pericytes to the pericyte soma is linear with distance.

    “then if this reduction is linear with distance the resistance of the capillary segment from the soma to the midpoint is given by k.L.(r12+r1.r2+r22)/(3.r13r23)”

  • The authors state this as an assumption.

    The pressure is fixed at the pial end of penetrating arterioles and venules.

    “if the pressure is fixed at the pial end of penetrating arterioles and venules”
7 of 7

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?

  • Recovery of neuron and neurovascular unit morphology is associated with improvement of neurovascular coupling as indicated by whisker pad electrical stimulation and laser speckle contrast imaging.

    “Such recovery of neuron and NVU morphology is associated with the improvement of neurovascular coupling as indicated by a whisker pad electrical stimulation and laser speckle contrast imaging (LSCI) experiment (Figure 6f).[ 37 ]”

    From Multifunctional Nanostructure RAP‐RL Rescues Alzheimer's Cognitive Deficits through Remodeling the Neurovascular Unit (2021) · cites this paper as [37]

    The Materials and Methods section ‘Experiments in vivo on AD mice’ describes measuring vessel diameter with two-photon microscopy, not whisker-pad stimulation or laser speckle contrast imaging (page unavailable). The ‘Reversal of Aβ-evoked capillary constriction’ section reports reversal of constriction in brain slices, but does not link recovery of neuron or neurovascular-unit morphology to improved neurovascular coupling. Searches for the stated methods and association found no supporting passage in our copy. (LLM, conf=0.75)

    Experimental — accuracy not yet measured

  • Aβ causes capillary constriction in human cortical slices by acting on pericytes to generate reactive oxygen species leading to endothelin-1 release.

    “A recent study shows that the presence of Aβ also causes capillary constriction in human cortical slices by acting on pericytes to generate reactive oxygen species (ROS) leading to endothelin-1 release”

    From Alzheimer Disease: An Update on Pathobiology and Treatment Strategies (2019) · cites this paper as Nortley et al., 2019

  • NOX4 in pericytes is the major source of ROS which is involved in the constriction of capillaries early in the response to Aβ.

    “Similarly, a recent study has suggested that NOX4 in pericytes is the major source of ROS which is involved in the constriction of capillaries early in the response to Aβ [48].”

    From NOX4 promotes ferroptosis of astrocytes by oxidative stress-induced lipid peroxidation via the impairment of mitochondrial metabolism in Alzheimer’s diseases (2021) · cites this paper as [48]

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.

  • EC50 result is assigned to two different figures

    Minor

    The results section places the 4.7 nM EC50 in Fig. 2D, but the methods section says the same measurement is in Fig. 1D. Elsewhere, Fig. 1D is identified as showing α-smooth-muscle-actin labeling of pericytes.

1 of 1

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Authors
Nortley, R., Korte, N., Izquierdo, P., Hirunpattarasilp, C., Mishra, A., Jaunmuktane, Z., Kyrargyri, V., Pfeiffer, T., Khennouf, L., Madry, C., Gong, H., Richard-Loendt, A., Huang, W., Saito, T., Saido, T. C., Brandner, S., Sethi, H., & Attwell, D.
Affiliations
  • University College London (GB)
  • Oregon Health & Science University (US)
  • National Hospital for Neurology and Neurosurgery (GB)
  • Saarland University (DE)
  • RIKEN Center for Brain Science (JP)
  • UCL Queen Square Institute of Neurology (GB)
Corresponding author
  • Korte, Nils
  • Izquierdo, Pablo
  • Hirunpattarasilp, Chanawee
  • Mishra, Anusha
  • Jaunmuktane, Zane
  • Kyrargyri, Vasiliki
  • Attwell, David
ORCID
Venue
Science
Publisher
American Association for the Advancement of Science (AAAS)
Published
2019-07-19
Volume
365
Issue
6450
ISSN
  • 0036-8075 (ISSN-L)
  • 1095-9203
DOI
10.1126/science.aav9518
PMC
PMC6658218
OpenAlex
W2951514146
Semantic Scholar
cc2df1df8221a1fa3d428338a5ead55bc1a47948
Cited by
682
References
53
Citations by year
2026: 64 · 2025: 90 · 2024: 105 · 2023: 108 · 2022: 93 · 2021: 102 · 2020: 102 · 2019: 16 · 2013: 1
FWCI
34.70
Type
journal article
Language
en
Open access
Locations
  • Science (publishedVersion)
  • bioRxiv (Cold Spring Harbor Laboratory) (acceptedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
  • UCL Discovery (University College London) (submittedVersion)
Funders
  • Wellcome Trust (099222, PhD studentship)
  • European Research Council (BrainPower & BrainEnergy)
  • Deutsche Forschungsgemeinschaft (KI 503/14-1 and SFB894)
  • EMBO (Fellowship)
  • Lundbeckfonden (Fellowship)
  • national institute of health research (Biomedical Research Centre)
  • Leonard Wolfson Experimental Neurology Centre (PhD studentship)
  • BBSRC (PhD studentship)
  • Chulabhorn Royal Academy (PhD studentship)
Topics
  • Life Sciences › Neuroscience › Neurology › Barrier Structure and Function Studies
  • Health Sciences › Medicine › Physiology › Alzheimer's disease research and treatments
  • Life Sciences › Neuroscience › Neurology › Neuroinflammation and Neurodegeneration Mechanisms
Keywords
amyloid-beta oligomers, Alzheimer's disease, pericytes, brain capillaries, cerebral blood flow, vasoconstriction, mouse models of Alzheimer's disease
MeSH terms
Alzheimer Disease, Animals, Hypoxia, Biopsy, Capillaries, Cerebral Cortex, Cerebrovascular Circulation, Constriction, Pathologic, Humans, Vascular Resistance, Signal Transduction, Amyloid beta-Peptides, Rats, Sprague-Dawley, Reactive Oxygen Species, Endothelin-1, Pericytes, Receptor, Endothelin A, Mice, Rats, Protein Multimerization

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 2026-10-10.

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

Statistics and arithmetic are recomputed, not judged.

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