TY - JOUR
T1 - Contributions of degradation and brain-to-blood elimination across the blood-brain barrier to cerebral clearance of human amyloid-β peptide(1-40) in mouse brain
AU - Ito, Shingo
AU - Matsumiya, Kohta
AU - Ohtsuki, Sumio
AU - Kamiie, Junichi
AU - Terasaki, Tetsuya
PY - 2013/11
Y1 - 2013/11
N2 - The purpose of the present study was to estimate the relative contributions of degradation and brain-to-blood elimination processes to the clearance of microinjected human amyloid-β peptide(1-40) (hAβ(1-40)) from mouse cerebral cortex, using a solid-phase extraction method together with a newly developed ultraperformance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) quantitation method for intact hAβ(1-40). The clearance rate constant of hAβ(1-40) in mouse cerebral cortex was determined to be 3.21 × 10-2/min under conditions where the saturable brain-to-blood elimination process across the blood-brain barrier (BBB) was expected to be saturated. Thus, this clearance rate constant should mainly reflect degradation. The [ 125 I]hAβ(1-40) elimination rate across the BBB under nonsaturating conditions was determined to be 1.48 × 10-2/min. Inhibition studies suggested that processes sensitive to insulin and phosphoramidon, which inhibit neprilysin, insulin-degrading enzyme, and endothelin-converting enzyme, are involved not only in degradation, but also in elimination of hAβ(1-40). In conclusion, our results suggest a dominant contribution of degradation to cerebral hAβ(1-40) clearance, and also indicate that a sequential process of degradation and elimination of degradation products is involved in cerebral hAβ(1-40) clearance.
AB - The purpose of the present study was to estimate the relative contributions of degradation and brain-to-blood elimination processes to the clearance of microinjected human amyloid-β peptide(1-40) (hAβ(1-40)) from mouse cerebral cortex, using a solid-phase extraction method together with a newly developed ultraperformance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) quantitation method for intact hAβ(1-40). The clearance rate constant of hAβ(1-40) in mouse cerebral cortex was determined to be 3.21 × 10-2/min under conditions where the saturable brain-to-blood elimination process across the blood-brain barrier (BBB) was expected to be saturated. Thus, this clearance rate constant should mainly reflect degradation. The [ 125 I]hAβ(1-40) elimination rate across the BBB under nonsaturating conditions was determined to be 1.48 × 10-2/min. Inhibition studies suggested that processes sensitive to insulin and phosphoramidon, which inhibit neprilysin, insulin-degrading enzyme, and endothelin-converting enzyme, are involved not only in degradation, but also in elimination of hAβ(1-40). In conclusion, our results suggest a dominant contribution of degradation to cerebral hAβ(1-40) clearance, and also indicate that a sequential process of degradation and elimination of degradation products is involved in cerebral hAβ(1-40) clearance.
KW - Alzheimer's disease
KW - Aβ-degrading enzyme
KW - amyloid-β peptide
KW - blood-brain barrier
KW - efflux transport
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UR - http://www.scopus.com/inward/citedby.url?scp=84887057897&partnerID=8YFLogxK
U2 - 10.1038/jcbfm.2013.125
DO - 10.1038/jcbfm.2013.125
M3 - Article
C2 - 23963369
AN - SCOPUS:84887057897
VL - 33
SP - 1770
EP - 1777
JO - Journal of Cerebral Blood Flow and Metabolism
JF - Journal of Cerebral Blood Flow and Metabolism
SN - 0271-678X
IS - 11
ER -