TY - JOUR
T1 - Semimechanistic Population Pharmacokinetic Modeling to Investigate Amyloid Beta Trafficking and Accumulation at the BBB Endothelium
AU - Wang, Zengtao
AU - Sharda, Nidhi
AU - Curran, Geoffry L.
AU - Li, Ling
AU - Lowe, Val J.
AU - Kandimalla, Karunya K.
N1 - Publisher Copyright:
©
PY - 2021/11/1
Y1 - 2021/11/1
N2 - Elevated exposure to toxic amyloid beta (Aβ) peptides and consequent blood-brain barrier (BBB) dysfunction are believed to promote vasculopathy in Alzheimer's disease (AD). However, the accumulation kinetics of different Aβ isoforms within the BBB endothelium and how it drives BBB dysfunction are not clearly characterized. Using single positron emission computed tomography (SPECT)-computed tomography (CT) dynamic imaging coupled with population pharmacokinetic modeling, we investigated the accumulation kinetics of Aβ40 and Aβ42 in the BBB endothelium. Brain clearance was quantified after intracerebral administration of 125I-Aβ, and BBB-mediated transport was shown to account for 54% of 125I-Aβ40 total clearance. A brain influx study demonstrated lower values of both maximal rate (Vmax) and Michaelis constant (Km) for 125I-Aβ42 compared to 125I-Aβ40. Validated by a transcytosis study in polarized human BBB endothelial cell (hCMEC/D3) monolayers, model simulations demonstrated impaired exocytosis was responsible for inefficient permeability and enhanced accumulation of Aβ42 in the BBB endothelium. Further, both isoforms were shown to disrupt the exocytosis machinery of BBB endothelial cells so that a vicious cycle could be generated. The validated model was able to capture changes in Aβ steady-state levels in plasma as well as the brain during AD progression and allowed us to predict the kinetics of Aβ accumulation in the BBB endothelium.
AB - Elevated exposure to toxic amyloid beta (Aβ) peptides and consequent blood-brain barrier (BBB) dysfunction are believed to promote vasculopathy in Alzheimer's disease (AD). However, the accumulation kinetics of different Aβ isoforms within the BBB endothelium and how it drives BBB dysfunction are not clearly characterized. Using single positron emission computed tomography (SPECT)-computed tomography (CT) dynamic imaging coupled with population pharmacokinetic modeling, we investigated the accumulation kinetics of Aβ40 and Aβ42 in the BBB endothelium. Brain clearance was quantified after intracerebral administration of 125I-Aβ, and BBB-mediated transport was shown to account for 54% of 125I-Aβ40 total clearance. A brain influx study demonstrated lower values of both maximal rate (Vmax) and Michaelis constant (Km) for 125I-Aβ42 compared to 125I-Aβ40. Validated by a transcytosis study in polarized human BBB endothelial cell (hCMEC/D3) monolayers, model simulations demonstrated impaired exocytosis was responsible for inefficient permeability and enhanced accumulation of Aβ42 in the BBB endothelium. Further, both isoforms were shown to disrupt the exocytosis machinery of BBB endothelial cells so that a vicious cycle could be generated. The validated model was able to capture changes in Aβ steady-state levels in plasma as well as the brain during AD progression and allowed us to predict the kinetics of Aβ accumulation in the BBB endothelium.
KW - Alzheimer's disease
KW - amyloid beta proteins
KW - blood-brain barrier
KW - population pharmacokinetic modeling
KW - transcytosis
UR - http://www.scopus.com/inward/record.url?scp=85118798388&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85118798388&partnerID=8YFLogxK
U2 - 10.1021/acs.molpharmaceut.1c00549
DO - 10.1021/acs.molpharmaceut.1c00549
M3 - Article
C2 - 34664956
AN - SCOPUS:85118798388
SN - 1543-8384
VL - 18
SP - 4148
EP - 4161
JO - Molecular pharmaceutics
JF - Molecular pharmaceutics
IS - 11
ER -