caa a22 4500 477125751 CHVBK 20180405111649.0 cr unu---uuuuu 170330e19970601xx s 000 0 eng 10.1023/A:1012150405949 doi (NATIONALLICENCE)springer-10.1023/A:1012150405949 Evidence for Diminished Functional Expression of Intestinal Transporters in Caco-2 Cell Monolayers at High Passages [Elektronische Daten] [Hongshi Yu, Thomas Cook, Patrick Sinko] Purpose. To investigate the effects of passaging on the intrinsic membrane transport parameters of compounds absorbed by means of passive and carrier-mediated processes in the Caco-2 cell line. Methods. Caco-2 cells at low (28−36) and high (93−108) passage numbers were used to evaluate the transport characteristics of model compounds for paracellular diffusion (mannitol), transcellular diffusion (progesterone) and carrier-mediated transport (cephalexin, cephradine, phenylalanine, proline, and taurocholic acid) using side-by-side diffusion chambers. Intrinsic intestinal transport parameters were determined by correcting the effective permeability for potential biases introduced by the microporous filter and aqueous boundary layer. Intrinsic maximal flux (J max, Michaelis constant (K m) and carrier permeability (P c) were determined as a function of passage number. Results. Compared to the low passaged cells, the high passaged Caco-2 cells were characterized by less morphological heterogeneity, higher transepithelial electrical resistance, higher transcellular diffusion, lower paracellular diffusion, lower carrier-mediated transport and lower alkaline phosphatase activity. The use of effective transport parameters overestimated the K m and underestimated P c but had no effect on J max. Conclusions. The current results provide experimental evidence that the passaging process significantly affects the biological characteristics and transport properties of Caco-2 cell monolayers. The effects are consistent with a reduction in the functional expression of a brush border enzyme and several transport proteins as passage number is increased. The underlying basis for this appears to be a selection of fast-growing subpopulations from the original heterogeneous Caco-2 cell line during passaging. Plenum Publishing Corporation, 1997 aqueous boundary layer nationallicence brush border enzymes nationallicence carrier-mediated transport nationallicence diffusion chamber nationallicence heterogeneity nationallicence permeability nationallicence Yu Hongshi College of Pharmacy, Rutgers University, P.O. Box 789, 08855, Piscataway, New Jersey aut Cook Thomas College of Pharmacy, Rutgers University, P.O. Box 789, 08855, Piscataway, New Jersey aut Sinko Patrick College of Pharmacy, Rutgers University, P.O. Box 789, 08855, Piscataway, New Jersey aut Pharmaceutical Research Kluwer Academic Publishers-Plenum Publishers 14/6(1997-06-01), 757-762 0724-8741 14:6<757 1997 14 11095 https://doi.org/10.1023/A:1012150405949 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1012150405949 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Yu Hongshi College of Pharmacy, Rutgers University, P.O. Box 789, 08855, Piscataway, New Jersey aut NATIONALLICENCE 700 1- Cook Thomas College of Pharmacy, Rutgers University, P.O. Box 789, 08855, Piscataway, New Jersey aut NATIONALLICENCE 700 1- Sinko Patrick College of Pharmacy, Rutgers University, P.O. Box 789, 08855, Piscataway, New Jersey aut NATIONALLICENCE 773 0- Pharmaceutical Research Kluwer Academic Publishers-Plenum Publishers 14/6(1997-06-01), 757-762 0724-8741 14:6<757 1997 14 11095 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer