title: Diadenosine tetraphosphate improves adrenergic anti-glaucomatous drug delivery and efficiency.
abstract: The effect of the dinucleotide P(1), P(4)-Di (adenosine-5') tetraphosphate (Ap4A) in improving adrenergic anti-glaucomatous delivery by modifying the tight junction proteins of the corneal epithelium was evaluated. Stratified human corneal epithelial cells (HCLE) were treated with Ap4A (100 μM) for 5 min and TJ protein levels and barrier function were analysed by western blotting and transepithelial electrical resistance (TEER), respectively. Western blot experiments showed a significant reduction at 2 h (45% reduction of ZO-1 and 65% reduction of occludin protein levels) as compared to non-treated (control) cells. Two hours after Ap4A treatment, TEER values were significantly reduced (65% as compared to control levels (p < 0.001)), indicating an increase in corneal barrier permeability. Topical application of Ap4A in New Zealand white rabbits two hours before the instillation of the hypotensor compounds (the α2-adrenergic receptor agonist, brimonidine and the β-adrenergic receptor antagonist, timolol), improved the delivery of these compounds to the anterior chamber as well as their hypotensive action on the intraocular pressure. The results obtained showed that, when Ap4A was topically applied two hours before the adrenergic compounds, the concentration of brimonidine in the aqueous humour increased from 64.3 ± 5.3 nM to 240.6 ± 8.6 nM and from 58.9 ± 9.2 nM to 183.7 ± 6.8 nM in the case of timolol, which also produces a more profound effect on IOP. Therefore, Ap4A treatment results in a better entrance of adrenergic anti-glaucomatous compounds within the eye and consequently improved therapeutic efficiency by increasing corneal epithelial barrier permeability.
authors.affiliation: Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Loma
authors.affiliation: Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Guzman-Aranguez
authors.affiliation: Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Spain.
authors.forename: Maria Jesus
authors.initials: MJ
authors.lastname: Perez de Lara
authors.affiliation: Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Spain. Electronic address: jpintor@ucm.es.
authors.forename: Jesus
authors.initials: J
authors.lastname: Pintor
mesh_terms: D058647:Adrenergic alpha-2 Receptor Agonists / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001082:Aqueous Humor / Q000378:metabolism*; D015153:Blotting, Western; D000068438:Brimonidine Tartrate; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured; D015226:Dinucleoside Phosphates / Q000494:pharmacology*; D016503:Drug Delivery Systems; D017097:Electric Impedance; D019573:Epithelium, Corneal / Q000187:drug effects* / Q000378:metabolism; D005901:Glaucoma / Q000188:drug therapy; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects; D008297:Male; D062793:Occludin / Q000378:metabolism; D011810:Quinoxalines / Q000008:administration & dosage; D011817:Rabbits; D019108:Tight Junctions / Q000187:drug effects* / Q000378:metabolism; D013999:Timolol / Q000008:administration & dosage; D062826:Zonula Occludens-1 Protein / Q000378:metabolism
chemical_list: D058647:Adrenergic alpha-2 Receptor Agonists; D000319:Adrenergic beta-Antagonists; D000959:Antihypertensive Agents; D015226:Dinucleoside Phosphates; C568985:OCLN protein, human; D062793:Occludin; D011810:Quinoxalines; C569042:TJP1 protein, human; D062826:Zonula Occludens-1 Protein; D000068438:Brimonidine Tartrate; C020733:diadenosine tetraphosphate; D013999:Timolol
keywords: Brimonidine; Corneal epithelium; Diadenosine tetraphosphate; Drug delivery; Glaucoma; Intraocular pressure; Tight junction; Timolol