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Roberts KF, Elbert DL, Kasten TP, Patterson BW, Sigurdson WC, Connors RE, Ovod V, Munsell LY, Mawuenyega KG, Miller-Thomas MM, Moran CJ, Cross DT, Derdeyn CP, Bateman RJ. Amyloid-β efflux from the central nervous system into the plasma. Ann Neurol 2014; 76:837-44. [PMID: 25205593 PMCID: PMC4355962 DOI: 10.1002/ana.24270] [Citation(s) in RCA: 186] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 08/28/2014] [Accepted: 09/04/2014] [Indexed: 01/05/2023]
Abstract
OBJECTIVE The aim of this study was to measure the flux of amyloid-β (Aβ) across the human cerebral capillary bed to determine whether transport into the blood is a significant mechanism of clearance for Aβ produced in the central nervous system (CNS). METHODS Time-matched blood samples were simultaneously collected from a cerebral vein (including the sigmoid sinus, inferior petrosal sinus, and the internal jugular vein), femoral vein, and radial artery of patients undergoing inferior petrosal sinus sampling. For each plasma sample, Aβ concentration was assessed by 3 assays, and the venous to arterial Aβ concentration ratios were determined. RESULTS Aβ concentration was increased by ∼7.5% in venous blood leaving the CNS capillary bed compared to arterial blood, indicating efflux from the CNS into the peripheral blood (p < 0.0001). There was no difference in peripheral venous Aβ concentration compared to arterial blood concentration. INTERPRETATION Our results are consistent with clearance of CNS-derived Aβ into the venous blood supply with no increase from a peripheral capillary bed. Modeling these results suggests that direct transport of Aβ across the blood-brain barrier accounts for ∼25% of Aβ clearance, and reabsorption of cerebrospinal fluid Aβ accounts for ∼25% of the total CNS Aβ clearance in humans. Ann Neurol 2014;76:837-844.
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Affiliation(s)
- Kaleigh Filisa Roberts
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Donald L. Elbert
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Tom P. Kasten
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Bruce W. Patterson
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Wendy C. Sigurdson
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Rose E. Connors
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Vitaliy Ovod
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Ling Y. Munsell
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Kwasi G. Mawuenyega
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | | | - Christopher J. Moran
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Neurological Surgery, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Dewitte T. Cross
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Neurological Surgery, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Colin P. Derdeyn
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Neurological Surgery, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Randall J. Bateman
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Knight Alzheimer’s Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO 63110, USA
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Portelius E, Zetterberg H, Dean RA, Marcil A, Bourgeois P, Nutu M, Andreasson U, Siemers E, Mawuenyega KG, Sigurdson WC, May PC, Paul SM, Holtzman DM, Blennow K, Bateman RJ. Amyloid-β(1-15/16) as a marker for γ-secretase inhibition in Alzheimer's disease. J Alzheimers Dis 2013; 31:335-41. [PMID: 22531418 DOI: 10.3233/jad-2012-120508] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Amyloid-β (Aβ) producing enzymes are key targets for disease-modifying Alzheimer's disease (AD) therapies since Aβ trafficking is at the core of AD pathogenesis. Development of such drugs might benefit from the identification of markers indicating in vivo drug effects in the central nervous system. We have previously shown that Aβ(1-15) is produced by concerted β-and α-secretase cleavage of amyloid-β protein precursor (AβPP). Here, we test the hypothesis that this pathway is more engaged upon γ-secretase inhibition in humans, and cerebrospinal fluid (CSF) levels of Aβ(1-15/16) represent a biomarker for this effect. Twenty healthy men were treated with placebo (n = 5) or the γ-secretase inhibitor semagacestat (100 mg [n = 5], 140 mg [n = 5], or 280 mg [n = 5]). CSF samples were collected hourly over 36 hours and 10 time points were analyzed by immunoassay for Aβ(1-15/16), Aβ(x-38), Aβ(x-40), Aβ(x-42), sAβPPα, and sAβPPβ. The CSF concentration of Aβ(1-15/16) showed a dose-dependent response over 36 hours. In the 280 mg treatment group, a transient increase was seen with a maximum of 180% relative to baseline at 9 hours post administration of semagacestat. The concentrations of Aβ(x-38), Aβ(x-40), and Aβ(x-42) decreased the first 9 hours followed by increased concentrations after 36 hours relative to baseline. No significant changes were detected for CSF sAβPPα and sAβPPβ. Our data shows that CSF levels of Aβ(1-15/16) increase during treatment with semagacestat supporting its feasibility as a pharmacodynamic biomarker for drug candidates aimed at inhibiting γ-secretase-mediated AβPP-processing.
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Affiliation(s)
- Erik Portelius
- Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy, University of Gothenburg, Mölndal, Sweden.
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Wildsmith KR, Basak JM, Patterson BW, Pyatkivskyy Y, Kim J, Yarasheski KE, Wang JX, Mawuenyega KG, Jiang H, Parsadanian M, Yoon H, Kasten T, Sigurdson WC, Xiong C, Goate A, Holtzman DM, Bateman RJ. In vivo human apolipoprotein E isoform fractional turnover rates in the CNS. PLoS One 2012; 7:e38013. [PMID: 22675504 PMCID: PMC3366983 DOI: 10.1371/journal.pone.0038013] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 04/29/2012] [Indexed: 11/21/2022] Open
Abstract
Apolipoprotein E (ApoE) is the strongest genetic risk factor for Alzheimer's disease and has been implicated in the risk for other neurological disorders. The three common ApoE isoforms (ApoE2, E3, and E4) each differ by a single amino acid, with ApoE4 increasing and ApoE2 decreasing the risk of Alzheimer's disease (AD). Both the isoform and amount of ApoE in the brain modulate AD pathology by altering the extent of amyloid beta (Aβ) peptide deposition. Therefore, quantifying ApoE isoform production and clearance rates may advance our understanding of the role of ApoE in health and disease. To measure the kinetics of ApoE in the central nervous system (CNS), we applied in vivo stable isotope labeling to quantify the fractional turnover rates of ApoE isoforms in 18 cognitively-normal adults and in ApoE3 and ApoE4 targeted-replacement mice. No isoform-specific differences in CNS ApoE3 and ApoE4 turnover rates were observed when measured in human CSF or mouse brain. However, CNS and peripheral ApoE isoform turnover rates differed substantially, which is consistent with previous reports and suggests that the pathways responsible for ApoE metabolism are different in the CNS and the periphery. We also demonstrate a slower turnover rate for CSF ApoE than that for amyloid beta, another molecule critically important in AD pathogenesis.
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Affiliation(s)
- Kristin R. Wildsmith
- Department of Neurology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Jacob M. Basak
- Department of Neurology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Bruce W. Patterson
- Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Yuriy Pyatkivskyy
- Department of Neurology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Jungsu Kim
- Department of Neurology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Kevin E. Yarasheski
- Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Jennifer X. Wang
- Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Kwasi G. Mawuenyega
- Department of Neurology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Hong Jiang
- Department of Neurology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Maia Parsadanian
- Department of Neurology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Hyejin Yoon
- Department of Neurology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Tom Kasten
- Department of Neurology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Wendy C. Sigurdson
- Department of Neurology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Chengjie Xiong
- Department of Biostatistics, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Alison Goate
- Department of Neurology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, Missouri, United States of America
- Department of Genetics, Washington University School of Medicine, Saint Louis, Missouri, United States of America
- Hope Center for Neurological Disorders, Washington University School of Medicine, Saint Louis, Missouri, United States of America
- Knight Alzheimer‘s Disease Research Center, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - David M. Holtzman
- Department of Neurology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
- Hope Center for Neurological Disorders, Washington University School of Medicine, Saint Louis, Missouri, United States of America
- Knight Alzheimer‘s Disease Research Center, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Randall J. Bateman
- Department of Neurology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
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Bateman RJ, Siemers ER, Mawuenyega KG, Sigurdson WC, Yarasheski KE, Friedrich SW, DeMattos RB, May PC, Paul SM, Holtzman DM. Reply. Ann Neurol 2010. [DOI: 10.1002/ana.21930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Bateman RJ, Siemers ER, Mawuenyega KG, Wen G, Browning KR, Sigurdson WC, Yarasheski KE, Friedrich SW, Demattos RB, May PC, Paul SM, Holtzman DM. A gamma-secretase inhibitor decreases amyloid-beta production in the central nervous system. Ann Neurol 2009; 66:48-54. [PMID: 19360898 DOI: 10.1002/ana.21623] [Citation(s) in RCA: 248] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Accumulation of amyloid-beta (Abeta) by overproduction or underclearance in the central nervous system (CNS) is hypothesized to be a necessary event in the pathogenesis of Alzheimer's disease. However, previously, there has not been a method to determine drug effects on Abeta production or clearance in the human CNS. The objective of this study was to determine the effects of a gamma-secretase inhibitor on the production of Abeta in the human CNS. METHODS We utilized a recently developed method of stable-isotope labeling combined with cerebrospinal fluid sampling to directly measure Abeta production during treatment of a gamma-secretase inhibitor, LY450139. We assessed whether this drug could decrease CNS Abeta production in healthy men (age range, 21-50 years) at single oral doses of 100, 140, or 280mg (n = 5 per group). RESULTS LY450139 significantly decreased the production of CNS Abeta in a dose-dependent fashion, with inhibition of Abeta generation of 47, 52, and 84% over a 12-hour period with doses of 100, 140, and 280mg, respectively. There was no difference in Abeta clearance. INTERPRETATION Stable isotope labeling of CNS proteins can be utilized to assess the effects of drugs on the production and clearance rates of proteins targeted as potential disease-modifying treatments for Alzheimer's disease and other CNS disorders. Results from this approach can assist in making decisions about drug dosing and frequency in the design of larger and longer clinical trials for diseases such as Alzheimer's disease, and may accelerate effective drug validation. Ann Neurol 2009.
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Affiliation(s)
- Randall J Bateman
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA.
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