Chen, S-C., Eiting, K.T., Li1, A.A.W., Lamharzi, N. and Quay, S.C. Nastech Pharmaceutical Company Inc. 3450 Monte Villa Parkway, Bothell, WA 98021, USA. 1Bioengineering, University of Washington.

This study by researchers at Nastech Pharmaceuticals demonstrated that MatTek’s EpiAirway in vitro human tracheal/bronchial tissue equivalent can be used to identify lipids that rapidly and reversibly alter the tight junction permeability of human epithelial tissues. Tight junctions play an important role in regulating paracellular drug transport. The aim of this Nastech Pharmaceutical Co. study was to identify lipids that rapidly and reversibly alter tight junction permeability in epithelial tissue. Since tight junction proteins have been shown to associate with lipid raft structures (which themselves are comprised of unique lipids) and because certain classes of lipids have been shown to affect lipid raft structure, Nastech scientists developed a screen for identifying lipids that alter tight junction properties. Measurement of trans-epithelial electrical resistance (TER) was used to monitor tight junction activity on EpiAirway bronchial/tracheal epithelial tissues using a microtiter format. Among seven groups of lipids tested (sterols, sphingolipids, ceramides, glycosylated sphingosines, alkylglucosides, oxidized lipids, and ether lipids (PAF)), the latter four were identified as tight junction modulators. Individual lipids within these four separate classes showed up to 95% TER reduction at noncytotoxic concentrations. Alkylglucosides, however, showed very high cytotoxicity and low viability at concentrations (0.2- 0.4%) reported to enhance transmucosal absorption (Ahsan et al., 2003) compared to the other 3 lipid classes and a recently identified tight junction modulating peptide (Chen et al., 2005). TER reduction by 1-Palmitoyl-2-Glutaroyl-sn-Glycero-3-Phosphocholine (PGPC) occurred within 1 min after treatment. Recovery of TER to 90% of the control values occurred within 1 hr when the treatment time was less than 30 min. Several of the active lipids also showed enhanced permeation of FITC-labeled dextran (MW 3000), and Peptide YY (MW 4049.6). Immunofluorescence staining of PGPC-treated cells with antibodies against ZO-1, occludin and claudin 4 showed no detectable changes in tight junction structural morphology indicating that a non-destructive, sub-microscopic alteration in tight junction function may be involved in TER reduction and permeation enhancement. This study by Nastech Pharmaceutical Co., that made extensive use of EpiAirway tissues, demonstrated that three new classes of lipids, but not alkylglucosides, show potential utility for transmucosal drug delivery.


Bronchial/tracheal epithelial tissues, Claudin, EpiAirway, Epithelial tissue, Lipids, Occludin, Oxidized lipids, Paracellular drug transport, Permeation, Tight junction permeability, Tight junctions, Trans-epithelial electrical resistance (TER), Transmucosal absorption, Transmucosal drug delivery, Triton-x, Vascular system

Materials Tested

1,2-Dioleoyl-sn-Glycero-3 Ethylphosphocholine, 1,2-di-O-phytanyl-glycero-3-phosphocholine, 1-O-hexadecyl-2-acetoyl-sn-glycerol, 1-O-octadecyl-2-O-methyl-glycerol-3-phosphocholine, 16:0-09:0(ALDO)PC, 16:0-09:0(COOH)PC, 3-beta-hydroxy-5alpha-cholest-8(14)-en-15-one, C10 sucrose, C12 maltose, C12 sucrose, C14 maltose, C16-09:0, C6 glucose, C6 maltose, C7 glucose, C8 glucose, Cardiolipin (sodium salt), Ceramide (brain porcine), Ceramide C10:0, Ceramide C12:0, Ceramide C14:0, Ceramide C16:0, Ceramide C17:0, Ceramide C18:0, Ceramide C18:1, Ceramide C20:0, Ceramide C24:0, Ceramide C24:1, Ceramide C2:0, Ceramide C4:0, Ceramide C6:0, Ceramide C8:0, Cerebroside (brain porcine), Cerebroside Sulfatide (porcine), Dimethylsphingosine, Egg Ceramide, Galactosyl sphingosine, Glucosyl-sphingosine, Lactosyl(ß) Sphingosine, Lyso-PAF, N-acetoyl ceramide-1-phosphate, N-octanoyl ceramide-1-phosphate, PGPC1, POVPC, Phosphatidylinositol (Soy), Phosphatidylinositol (bovine), Platelet-Activation Factor, Porcine brain ganglioside, Sphingomyelin (brain porcine), Sphingosine-1-phosphate, Trimethylsphingosine

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