Ординатура / Офтальмология / Учебные материалы / Retinal Vascular Disease Joussen Springer

blood-brain barrier as defined by immunocytochemistry. Int Rev Cytol 127:57 – 109

41.Duncan BB, Schmidt MI (2006) The epidemiology of lowgrade chronic systemic inflammation and type 2 diabetes. Diabetes Technol Ther 8:7 – 17

42.Ebnet K, Suzuki A, Ohno S, Vestweber D (2004) Junctional adhesion molecules (JAMs): more molecules with dual functions? J Cell Sci 117:19 – 29

43.Enea NA, Hollis TM, Kern JA, Gardner TW (1989) Histamine H1 receptors mediate increased blood-retinal barrier permeability in experimental diabetes. Arch Ophthalmol 107:270 – 4

44.Engler C, Krogsaa B, Lund-Andersen H (1991) Blood-retina barrier permeability and its relation to the progression of diabetic retinopathy in type 1 diabetics. An 8-year followup study. Graefes Arch Clin Exp Ophthalmol 229:442 – 6

45.Etienne-Manneville S, Hall A (2003) Cdc42 regulates GSK3beta and adenomatous polyposis coli to control cell polarity. Nature 421:753 – 6

46.Fanning AS, Anderson JM (1999) Protein modules as organizers of membrane structure. Curr Opin Cell Biol 11:432 – 9

47.Fanning AS, Ma TY, Anderson JM (2002) Isolation and functional characterization of the actin binding region in the tight junction protein ZO-1. FASEB J 16:1835 – 7

48.Farquhar MG, Palade GE (1963) Junctional complexes in various epithelia. J Cell Biol 17:375 – 412

49.Fenstermacher J, Gross P, Sposito N, Acuff V, Pettersen S, Gruber K (1988) Structural and functional variations in capillary systems within the brain. Ann N Y Acad Sci 529:21 – 30

50.Festa A, D’Agostino R, Jr, Howard G, Mykkanen L, Tracy RP, Haffner SM (2000) Chronic subclinical inflammation as part of the insulin resistance syndrome: the Insulin Resistance Atherosclerosis Study (IRAS). Circulation 102: 42 – 7

51.Frank RN (1991) On the pathogenesis of diabetic retinopathy. A 1990 update. Ophthalmology 98:586 – 93

52.Frohlich M, Imhof A, Berg G, Hutchinson WL, Pepys MB, Boeing H, Muche R, Brenner H, Koenig W (2000) Association between C-reactive protein and features of the metabolic syndrome: a population-based study. Diabetes Care 23:1835 – 9

53.Fujimoto K (1995) Pericyte-endothelial gap junctions in developing rat cerebral capillaries: a fine structural study. Anat Rec 242:562 – 5

54.Fukuhara A, Irie K, Nakanishi H, Takekuni K, Kawakatsu T, Ikeda W, Yamada A, Katata T, Honda T, Sato T, Shimizu K, Ozaki H, Horiuchi H, Kita T, Takai Y (2002) Involvement of nectin in the localization of junctional adhesion molecule at tight junctions. Oncogene 21:7642 – 55

55.Fukuhara A, Irie K, Yamada A, Katata T, Honda T, Shimizu K, Nakanishi H, Takai Y (2002) Role of nectin in organization of tight junctions in epithelial cells. Genes Cells 7: 1059 – 72

56.Furuse M, Hata M, Furuse K, Yoshida Y, Haratake A, Sugitani Y, Noda T, Kubo A, Tsukita S (2002) Claudin-based tight junctions are crucial for the mammalian epidermal barrier: a lesson from claudin-1-deficient mice. J Cell Biol 156: 1099 – 111

57.Furuse M, Hirase T, Itoh M, Nagafuchi A, Yonemura S, Tsukita S, Tsukita S (1993) Occludin: a novel integral membrane protein localizing at tight junctions. J Cell Biol 123:1777 – 88

58.Garcia PJ, Spellman CW (2006) Should all diabetic patients receive statins? Curr Atheroscler Rep 8:13 – 8

diabetes. J Pathol 201:328 – 33

60.Gardner TW, Antonetti DA, Barber AJ, LaNoue KF, Nakamura M (2000) New insights into the pathophysiology of diabetic retinopathy: potential cell-specific therapeutic targets. Diabetes Technol Ther 2:601 – 8

61.Goldstein B (2000) Embryonic polarity: a role for microtubules. Curr Biol 10:R820 – 2

62.Gonzalez-Mariscal L, Betanzos A, Nava P, Jaramillo BE (2003) Tight junction proteins. Prog Biophys Mol Biol 81:1 – 44

63.Guillemot L, Hammar E, Kaister C, Ritz J, Caille D, Jond L, Bauer C, Meda P, Citi S (2004) Disruption of the cingulin gene does not prevent tight junction formation but alters gene expression. J Cell Sci 117:5245 – 56

64.Gumbiner B, Lowenkopf T, Apatira D (1991) Identification of a 160-kDa polypeptide that binds to the tight junction protein ZO-1. Proc Natl Acad Sci U S A 88:3460 – 4

65.Guo P, Weinstein AM, Weinbaum S (2003) A dual-pathway ultrastructural model for the tight junction of rat proximal tubule epithelium. Am J Physiol Renal Physiol 285:F241 – 57

66.Guo S, Kemphues KJ (1996) Molecular genetics of asymmetric cleavage in the early Caenorhabditis elegans embryo. Curr Opin Genet Dev 6:408 – 15

67.Haffner SM (2006) The metabolic syndrome: inflammation, diabetes mellitus, and cardiovascular disease. Am J Cardiol 97:3A–11A

68.Hammes HP (2005) Pericytes and the pathogenesis of diabetic retinopathy. Horm Metab Res 37 Suppl 1:39 – 43

69.Hammes HP, Lin J, Wagner P, Feng Y, Vom Hagen F, Krzizok T, Renner O, Breier G, Brownlee M, Deutsch U (2004) Angi- opoietin-2 causes pericyte dropout in the normal retina: evidence for involvement in diabetic retinopathy. Diabetes 53:1104 – 10

70.Harhaj NS, Felinski EA, Wolpert EB, Sundstrom JM, Gardner TW, Antonetti DA (2006) VEGF activation of protein kinase C stimulates occludin phosphorylation and contributes to endothelial permeability. IOVS (in press)

71.Haskins J, Gu L, Wittchen ES, Hibbard J, Stevenson BR (1998) ZO-3, a novel member of the MAGUK protein family found at the tight junction, interacts with ZO-1 and occludin. J Cell Biol 141:199 – 208

72.Hirase T, Kawashima S, Wong EY, Ueyama T, Rikitake Y, Tsukita S, Yokoyama M, Staddon JM (2001) Regulation of tight junction permeability and occludin phosphorylation by Rhoa-p160ROCK-dependent and -independent mechanisms. J Biol Chem 276:10423 – 31

73.Hirase T, Staddon JM, Saitou M, Ando-Akatsuka Y, Itoh M, Furuse M, Fujimoto K, Tsukita S, Rubin LL (1997) Occludin as a possible determinant of tight junction permeability in endothelial cells. J Cell Sci 110(14):1603 – 13

74.Hirschi KK, D’Amore PA (1997) Control of angiogenesis by the pericyte: molecular mechanisms and significance. EXS 79:419 – 28

75.Hofman P, van Blijswijk BC, Gaillard PJ, Vrensen GF, Schlingemann RO (2001) Endothelial cell hypertrophy induced by vascular endothelial growth factor in the retina: new insights into the pathogenesis of capillary nonperfusion. Arch Ophthalmol 119:861 – 6

76.Hurd TW, Gao L, Roh MH, Macara IG, Margolis B (2003) Direct interaction of two polarity complexes implicated in epithelial tight junction assembly. Nat Cell Biol 5:137 – 42

77.Jiang WG, Martin TA, Matsumoto K, Nakamura T, Mansel

Nystrom HC, Bergstrom G, Dejana E, Ostman A, Lindahl P, Betsholtz C (2003) Endothelial PDGF-B retention is required for proper investment of pericytes in the microvessel wall. Genes Dev 17:1835 – 40

96.Ling V (1997) Multidrug resistance: molecular mechanisms and clinical relevance. Cancer Chemother Pharmacol 40 Suppl:S3 – 8

97.Lu M, Kuroki M, Amano S, Tolentino M, Keough K, Kim I, Bucala R, Adamis AP (1998) Advanced glycation end products increase retinal vascular endothelial growth factor expression. J Clin Invest 101:1219 – 24

98.Lu M, Perez VL, Ma N, Miyamoto K, Peng HB, Liao JK, Adamis AP (1999) VEGF increases retinal vascular ICAM-1 expression in vivo. Invest Ophthalmol Vis Sci 40:1808 – 12

99.Lutty GA, McLeod DS, Merges C, Diggs A, Plouet J (1996) Localization of vascular endothelial growth factor in human retina and choroid. Arch Ophthalmol 114:971 – 7

100.Maines LW, Antonetti DA, Wolpert EB, Smith CD (2005) Evaluation of the role of P-glycoprotein in the uptake of paroxetine, clozapine, phenytoin and carbamazapine by bovine retinal endothelial cells. Neuropharmacology 49: 610 – 7

101.Mandell KJ, Parkos CA (2005) The JAM family of proteins. Adv Drug Deliv Rev 57:857 – 67

102.Marmor MF, Wolfensberger TJ (1998) The retinal pigment epithelium: function and disease. Oxford University Press, New York

103.Masuzawa K, Goto K, Jesmin S, Maeda S, Miyauchi T, Kaji Y, Oshika T, Hori S (2006) An endothelin type A receptor antagonist reverses upregulated VEGF and ICAM-1 levels in streptozotocin-induced diabetic rat retina. Curr Eye Res 31:79 – 89

104.Mazzon E, Puzzolo D, Caputi AP, Cuzzocrea S (2002) Role of IL-10 in hepatocyte tight junction alteration in mouse model of experimental colitis. Mol Med 8:353 – 66

105.McCarthy KM, Skare IB, Stankewich MC, Furuse M, Tsukita S, Rogers RA, Lynch RD, Schneeberger EE (1996) Occludin is a functional component of the tight junction. J Cell Sci 109(9):2287 – 98

106.McNeil E, Capaldo CT, Macara IG (2006) Zonula occlu- dens-1 function in the assembly of tight junctions in Madin-Darby canine kidney epithelial cells. Mol Biol Cell 17:1922 – 32

107.Miller SS, Edelman JL (1990) Active ion transport pathways in the bovine retinal pigment epithelium. J Physiol 424: 283 – 300

108.Miller SS, Hughes BA, Machen TE (1982) Fluid transport across retinal pigment epithelium is inhibited by cyclic AMP. Proc Natl Acad Sci U S A 79:2111 – 5

109.Miller SS, Steinberg RH (1977) Active transport of ions across frog retinal pigment epithelium. Exp Eye Res 25: 235 – 48

110.Mitamura Y, Takeuchi S, Matsuda A, Tagawa Y, Mizue Y, Nishihira J (2000) Hepatocyte growth factor levels in the vitreous of patients with proliferative vitreoretinopathy. Am J Ophthalmol 129:678 – 80

111.Mitic LL, Anderson JM (1998) Molecular architecture of tight junctions. Annu Rev Physiol 60:121 – 42

112.Miyamoto K, Hiroshiba N, Tsujikawa A, Ogura Y (1998) In vivo demonstration of increased leukocyte entrapment in retinal microcirculation of diabetic rats. Invest Ophthalmol Vis Sci 39:2190 – 4

113.Miyamoto K, Khosrof S, Bursell SE, Moromizato Y, Aiello LP, Ogura Y, Adamis AP (2000) Vascular endothelial

growth factor (VEGF)-induced retinal vascular permeability is mediated by intercellular adhesion molecule-1 (ICAM-1). Am J Pathol 156:1733 – 9

114.Miyoshi J, Takai Y (2005) Molecular perspective on tightjunction assembly and epithelial polarity. Adv Drug Deliv Rev 57:815 – 55

115.Moore TC, Moore JE, Kaji Y, Frizzell N, Usui T, Poulaki V, Campbell IL, Stitt AW, Gardiner TA, Archer DB, Adamis AP (2003) The role of advanced glycation end products in retinal microvascular leukostasis. Invest Ophthalmol Vis Sci 44:4457 – 64

116.Morcos Y, Hosie MJ, Bauer HC, Chan-Ling T (2001) Immunolocalization of occludin and claudin-1 to tight junctions in intact CNS vessels of mammalian retina. J Neurocytol 30:107 – 23

117.Moss SE, Klein R, Klein BE (1998) The 14-year incidence of visual loss in a diabetic population. Ophthalmology 105: 998 – 1003

118.Murata T, Ishibashi T, Inomata H (1993) Immunohistochemical detection of blood-retinal barrier breakdown in streptozotocin-diabetic rats. Graefes Arch Clin Exp Ophthalmol 231:175 – 7

119.Murata T, Nakagawa K, Khalil A, Ishibashi T, Inomata H, Sueishi K (1996) The relation between expression of vascular endothelial growth factor and breakdown of the blood-retinal barrier in diabetic rat retinas. Lab Invest 74:819 – 25

120.Nagy Z, Peters H, Huttner I (1984) Fracture faces of cell junctions in cerebral endothelium during normal and hyperosmotic conditions. Lab Invest 50:313 – 22

121.Nehls V, Denzer K, Drenckhahn D (1992) Pericyte involvement in capillary sprouting during angiogenesis in situ. Cell Tissue Res 270:469 – 74

122.Nelson WJ (2003) Adaptation of core mechanisms to generate cell polarity. Nature 422:766 – 74

123.Nielsen S, Smith BL, Christensen EI, Agre P (1993) Distribution of the aquaporin CHIP in secretory and resorptive epithelia and capillary endothelia. Proc Natl Acad Sci U S A 90:7275 – 9

124.Nitta T, Hata M, Gotoh S, Seo Y, Sasaki H, Hashimoto N, Furuse M, Tsukita S (2003) Size-selective loosening of the blood-brain barrier in claudin-5-deficient mice. J Cell Biol 161:653 – 60

125.Nusrat A, Brown GT, Tom J, Drake A, Bui TT, Quan C, Mrsny RJ (2005) Multiple protein interactions involving proposed extracellular loop domains of the tight junction protein occludin. Mol Biol Cell 16:1725 – 34

126.Oldendorf WH, Cornford ME, Brown WJ (1977) The large apparent work capability of the blood-brain barrier: a study of the mitochondrial content of capillary endothelial cells in brain and other tissues of the rat. Ann Neurol 1:409 – 17

127.Ostermann G, Weber KS, Zernecke A, Schroder A, Weber C (2002) JAM-1 is a ligand of the beta(2) integrin LFA-1 involved in transendothelial migration of leukocytes. Nat Immunol 3:151 – 8

128.Pardridge WM, Boado RJ, Farrell CR (1990) Brain-type glucose transporter (GLUT-1) is selectively localized to the blood-brain barrier. Studies with quantitative western blotting and in situ hybridization. J Biol Chem 265:18035 – 40

129.Petronczki M, Knoblich JA (2001) DmPAR-6 directs epithelial polarity and asymmetric cell division of neuroblasts in Drosophila. Nat Cell Biol 3:43 – 9

130.Philp NJ, Yoon H, Grollman EF (1998) Monocarboxylate

131.Pickup JC, Crook MA (1998) Is type II diabetes mellitus a disease of the innate immune system? Diabetologia 41: 1241 – 8

132.Qaum T, Xu Q, Joussen AM, Clemens MW, Qin W, Miyamoto K, Hassessian H, Wiegand SJ, Rudge J, Yancopoulos GD, Adamis AP (2001) VEGF-initiated blood-retinal barrier breakdown in early diabetes. Invest Ophthalmol Vis Sci 42:2408 – 13

133.Rao VV, Dahlheimer JL, Bardgett ME, Snyder AZ, Finch RA, Sartorelli AC, Piwnica-Worms D (1999) Choroid plexus epithelial expression of MDR1 P glycoprotein and multidrug resistance-associated protein contribute to the blood-cerebrospinal-fluid drug-permeability barrier. Proc Natl Acad Sci U S A 96:3900 – 5

134.Rizzolo LJ (1997) Polarity and the development of the outer blood-retinal barrier. Histol Histopathol 12:1057 – 67

135.Roh MH, Fan S, Liu CJ, Margolis B (2003) The Crumbs3Pals1 complex participates in the establishment of polarity in mammalian epithelial cells. J Cell Sci 116:2895 – 906

136.Roh MH, Liu CJ, Laurinec S, Margolis B (2002) The carboxyl terminus of zona occludens-3 binds and recruits a mammalian homologue of discs lost to tight junctions. J Biol Chem 277:27501 – 9

137.Romero IA, Radewicz K, Jubin E, Michel CC, Greenwood J, Couraud PO, Adamson P (2003) Changes in cytoskeletal and tight junctional proteins correlate with decreased permeability induced by dexamethasone in cultured rat brain endothelial cells. Neurosci Lett 344:112 – 6

138.Rothenberg M, Ling V (1989) Multidrug resistance: molecular biology and clinical relevance. J Natl Cancer Inst 81:907 – 10

139.Rubin LL, Staddon JM (1999) The cell biology of the blood-brain barrier. Annu Rev Neurosci 22:11 – 28

140.Rymer J, Miller SS, Edelman JL (2001) Epinephrineinduced increases in [Ca2+](in) and KCl-coupled fluid absorption in bovine RPE. Invest Ophthalmol Vis Sci 42: 1921 – 9

141.Saitou M, Furuse M, Sasaki H, Schulzke JD, Fromm M, Takano H, Noda T, Tsukita S (2000) Complex phenotype of mice lacking occludin, a component of tight junction strands. Mol Biol Cell 11:4131 – 42

142.Salathe EP, Venkataraman R (1982) Interaction of fluid movement and particle diffusion across capillary walls. J Biomech Eng 104:57 – 62

143.Sasaki H, Matsui C, Furuse K, Mimori-Kiyosue Y, Furuse M, Tsukita S (2003) Dynamic behavior of paired claudin strands within apposing plasma membranes. Proc Natl Acad Sci U S A 100:3971 – 6

144.Sato TN, Tozawa Y, Deutsch U, Wolburg-Buchholz K, Fujiwara Y, Gendron-Maguire M, Gridley T, Wolburg H, Risau W, Qin Y (1995) Distinct roles of the receptor tyrosine kinases Tie-1 and Tie-2 in blood vessel formation. Nature 376:70 – 4

145.Schinkel AH, Smit JJ, van Tellingen O, Beijnen JH, Wagenaar E, van Deemter L, Mol CA, van der Valk MA, Roba- nus-Maandag EC, te Riele HP, et al. (1994) Disruption of the mouse mdr1a P-glycoprotein gene leads to a deficiency in the blood-brain barrier and to increased sensitivity to drugs. Cell 77:491 – 502

146.Schinkel AH, Wagenaar E, Mol CA, van Deemter L (1996) P-glycoprotein in the blood-brain barrier of mice influ-

163.Takagi C, Bursell SE, Lin YW, Takagi H, Duh E, Jiang Z, Clermont AC, King GL (1996) Regulation of retinal hemodynamics in diabetic rats by increased expression and action of endothelin-1. Invest Ophthalmol Vis Sci 37:2504 – 18

164.Tavelin S, Hashimoto K, Malkinson J, Lazorova L, Toth I, Artursson P (2003) A new principle for tight junction modulation based on occludin peptides. Mol Pharmacol 64:1530 – 40

165.The Diabetes Control and Complications Trial Research Group (1993) The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med 329:977 – 86

166.The Diabetes Control and Complications Trial Research Group (1998) Early worsening of diabetic retinopathy in the Diabetes Control and Complications Trial. Arch Ophthalmol 116:874 – 86.

167.Turksen K, Troy TC (2004) Barriers built on claudins. J Cell Sci 117:2435 – 47

168.Uemura A, Ogawa M, Hirashima M, Fujiwara T, Koyama S, Takagi H, Honda Y, Wiegand SJ, Yancopoulos GD, Nishikawa S (2002) Recombinant angiopoietin-1 restores higherorder architecture of growing blood vessels in mice in the absence of mural cells. J Clin Invest 110:1619 – 28

169.Umeda K, Matsui T, Nakayama M, Furuse K, Sasaki H, Furuse M, Tsukita S (2004) Establishment and characterization of cultured epithelial cells lacking expression of ZO-1. J Biol Chem 279:44785 – 94

170.Van Itallie CM, Anderson JM (1997) Occludin confers adhesiveness when expressed in fibroblasts. J Cell Sci 110(9):1113 – 21

171.Van Itallie CM, Fanning AS, Anderson JM (2003) Reversal of charge selectivity in cation or anion-selective epithelial lines by expression of different claudins. Am J Physiol Renal Physiol 285:F1078 – 84

172.Vialettes B, Silvestre-Aillaud P, Atlan-Gepner C (1994) [Outlook for the future in the treatment of diabetic retinopathy]. Diabetes Metab 20:229 – 34

173.Vietor I, Bader T, Paiha K, Huber LA (2001) Perturbation of the tight junction permeability barrier by occludin loop peptides activates beta-catenin/TCF/LEF-mediated transcription. EMBO Rep 2:306 – 12

174.Vincent AM, Brownlee M, Russell JW (2002) Oxidative stress and programmed cell death in diabetic neuropathy. Ann N Y Acad Sci 959:368 – 83

175.Vinores SA, McGehee R, Lee A, Gadegbeku C, Campochiaro PA (1990) Ultrastructural localization of blood-retinal barrier breakdown in diabetic and galactosemic rats. J Histochem Cytochem 38:1341 – 52

176.Vitale S, Maguire MG, Murphy RP, Hiner CJ, Rourke L, Sackett C, Patz A (1995) Clinically significant macular edema in type I diabetes. Incidence and risk factors. Ophthalmology 102:1170 – 6

177.Vorbrodt AW, Dobrogowska DH (2003) Molecular anatomy of intercellular junctions in brain endothelial and epithelial barriers: electron microscopist’s view. Brain Res Brain Res Rev 42:221 – 42

178.Walsh SV, Hopkins AM, Nusrat A (2000) Modulation of tight junction structure and function by cytokines. Adv Drug Deliv Rev 41:303 – 13

179.Wang W, Dentler WL, Borchardt RT (2001) VEGF increases BMEC monolayer permeability by affecting occludin expression and tight junction assembly. Am J Physiol Heart Circ Physiol 280:H434 – 40

180.Wang Z, Mandell KJ, Parkos CA, Mrsny RJ, Nusrat A (2005) The second loop of occludin is required for suppression of Raf1-induced tumor growth. Oncogene 24: 4412 – 20

181.Wen H, Watry DD, Marcondes MC, Fox HS (2004) Selective decrease in paracellular conductance of tight junctions: role of the first extracellular domain of claudin-5. Mol Cell Biol 24:8408 – 17

182.Wilcox ER, Burton QL, Naz S, Riazuddin S, Smith TN, Ploplis B, Belyantseva I, Ben-Yosef T, Liburd NA, Morell RJ, Kachar B, Wu DK, Griffith AJ, Riazuddin S, Friedman TB (2001) Mutations in the gene encoding tight junction clau- din-14 cause autosomal recessive deafness DFNB29. Cell 104:165 – 72

183.Williams CD, Rizzolo LJ (1997) Remodeling of junctional complexes during the development of the outer blood-ret- inal barrier. Anat Rec 249:380 – 8

184.Wittchen ES, Haskins J, Stevenson BR (1999) Protein interactions at the tight junction. Actin has multiple binding partners, and ZO-1 forms independent complexes with ZO-2 and ZO-3. J Biol Chem 274:35179 – 85

185.Wolburg H, Lippoldt A (2002) Tight junctions of the blood-brain barrier: development, composition and regulation. Vascul Pharmacol 38:323 – 37

186.Wolburg H, Wolburg-Buchholz K, Kraus J, Rascher-Egg- stein G, Liebner S, Hamm S, Duffner F, Grote EH, Risau W, Engelhardt B (2003) Localization of claudin-3 in tight junctions of the blood-brain barrier is selectively lost during experimental autoimmune encephalomyelitis and human glioblastoma multiforme. Acta Neuropathol (Berl) 105:586 – 92

187.Wolburg H, Wolburg-Buchholz K, Liebner S, Engelhardt B (2001) Claudin-1, claudin-2 and claudin-11 are present in tight junctions of choroid plexus epithelium of the mouse. Neurosci Lett 307:77 – 80

188.Wong V, Gumbiner BM (1997) A synthetic peptide corresponding to the extracellular domain of occludin perturbs

(2001) Clathrin exchange during clathrin-mediated endocytosis. J Cell Biol 155:291 – 300

190.Xu Q, Qaum T, Adamis AP (2001) Sensitive blood-retinal barrier breakdown quantitation using Evans blue. Invest Ophthalmol Vis Sci 42:789 – 94

191.Yamamoto T, Harada N, Kano K, Taya S, Canaani E, Matsuura Y, Mizoguchi A, Ide C, Kaibuchi K (1997) The Ras target AF-6 interacts with ZO-1 and serves as a peripheral component of tight junctions in epithelial cells. J Cell Biol 139:785 – 95

192.Yamanaka T, Horikoshi Y, Suzuki A, Sugiyama Y, Kitamura K, Maniwa R, Nagai Y, Yamashita A, Hirose T, Ishikawa H, Ohno S (2001) PAR-6 regulates aPKC activity in a novel way and mediates cell-cell contact-induced formation of the epithelial junctional complex. Genes Cells 6: 721 – 31

193.Yokota T, Ma RC, Park JY, Isshiki K, Sotiropoulos KB, Rauniyar RK, Bornfeldt KE, King GL (2003) Role of protein kinase C on the expression of platelet-derived growth factor and endothelin-1 in the retina of diabetic rats and cultured retinal capillary pericytes. Diabetes 52:838 – 45

194.Yoon H, Fanelli A, Grollman EF, Philp NJ (1997) Identification of a unique monocarboxylate transporter (MCT3) in retinal pigment epithelium. Biochem Biophys Res Commun 234:90 – 4

195.Yu AS, McCarthy KM, Francis SA, McCormack JM, Lai J, Rogers RA, Lynch RD, Schneeberger EE (2005) Knockdown of occludin expression leads to diverse phenotypic alterations in epithelial cells. Am J Physiol Cell Physiol 288:C1231 – 41

196.Zettl KS, Sjaastad MD, Riskin PM, Parry G, Machen TE, Firestone GL (1992) Glucocorticoid-induced formation of tight junctions in mouse mammary epithelial cells in vitro. Proc Natl Acad Sci U S A 89:9069 – 73

154

8 I

I Pathogenesis of Retinal Vascular Disease

8.2MRI Studies of Blood-Retinal Barrier: New Potential for Translation of Animal Results to Human Application

B.A. Berkowitz

Core Messages

Blood-retinal barrier breakdown can contribute to abnormal accumulation of water in the retina

Traditional methods for clinical evaluation of macular edema include fluorescein angiography, optical coherence tomography, and vitreous fluorophotometry

Dynamic contrast enhanced MRI (DCE-MRI) with gadolinium diethylenetriaminepentaace-

tic acid (Gd-DTPA) allows for in vivo quantitative measurement of blood-retinal barrier breakdown

DCE-MRI was assessed in a variety of experimental and clinical conditions (e.g., focal retinal photocoagulation, endophthalmitis, diabetic retinopathy)

DCE-MRI allows for an exact determination of blood-retinal breakdown

8.2.1 Introduction

Abnormal accumulation of water in the retina (i.e., retinal edema) is commonly associated with retinal vessel diseases such as diabetes. Edema that develops in the macula secondary to diabetes is often linked with major visual loss [21]. However, despite decades of study, current treatment options for retinal edema remain limited to, primarily, laser photocoagulation. However, photocoagulation is destructive, does not restore lost vision, and is helpful in only about 50 % of the patients [1]. Better appreciation of the underlying pathophysiology associated with edema formation is likely to improve diagnosis and medical care for retinal edema. Currently it is understood that fluid buildup in the retina can develop in intracellular and/or extracellular compartments. The blood-retinal barrier (BRB) refers to tight cell-cell junctions of the retinal vascular endothelium (also known as inner BRB) as well as tight junctions of the retinal pigment epithelium (or outer BRB). Intracellular edema (or cytotoxic edema) is defined as cellular swelling that occurs without opening of the BRB. Extracellular (or vasogenic) edema is characterized by retinal thickening in association with loss of BRB integrity [35]. Consequently, the development of optimal strategies for treating retinal edema may depend on determining the ratio of the contribution of intraand extracellular mechanisms to edema and measuring how this ratio changes between patients, between different retinopathies, and during disease progression [32].

Traditional methods for evaluating the efficacy of medical therapy for retinal edema or deciding on endpoints for therapeutic intervention (e.g., visual acuity and seven-field stereoscopic fundus photography) detect only gross changes that occur late in the course of the disease. With these endpoints, studies require large numbers of patients with many years of follow-up before evidence-based conclusions can be drawn [35]. Fluorescein angiography (FA), an essential tool in the current clinical diagnosis and management of retinal diseases, is a rapid and straightforward photographic technique that allows localization of fluorescein leakage due to BRB breakdown, but cannot quantify BRB damage in physiologic terms, such as the permeability surface area product (PS). In other words, only subjective determination of the magnitude of BRB damage is possible with FA and this prevents analytic staging of treatment efficacies (using, for example, BRB PS) within and between patients over time. Furthermore, as a tracer, fluorescein is far from ideal because, among other variables, it is bound to serum protein, has a complex pharmacokinetic profile that complicates evaluating the fluorescein concentration plasma integral, is metabolized to different fluores- cein-based metabolites which can confound interpretation, and enters the vitreous through a passive mechanism but is actively removed from vitreous to choroid [49, 50, 51]. Importantly, the location of BRB damage, as measured by FA, is not always linked with regions of edema [37]. For these reasons, FA remains

a suboptimal approach for quantitatively evaluating new or existing treatment responses. Alternatively, retinal fluid buildup in either intraor extracellular compartments can produce an increase in retinal thickness that is measurable using analytic techniques such as ocular coherence tomography (OCT). Because it only measures retinal thickness, OCT is unable to determine whether the type of edema is intraor extracellular [32]. In addition, interrogating the exact same retinal region during repeated exams using clinically available OCT machines can be difficult. This registration problem may limit the accuracy and applicability of OCT measurement of longitudinal changes in retinal thickness. Therefore, while the methods mentioned have a proven usefulness in the clinic, they are also somewhat limited in their diagnostic and prognostic applicability.

Vitreous fluorophotometry (VFP), a fluoresceinbased method, was developed to address some of these concerns [12]. Unlike FA, which presents a twodimensional map of fluorescence across the retina, but not fluorescein concentrations, VFP measures a one-dimensional spatial profile of fluorescein concentration in the vitreous that can be used to quantitate BRB damage. However, VFP is not widely avail-

able, it cannot be performed in the presence of opti-

cal opacities (such as cataract), its interpretation can I 8 be confounded by changes in vitreous fluidity, and it suffers from the problems associated with fluoresce-

in that are listed above [35, 50, 51]. Additionally, data must be carefully collected to take into account the influence of the potentially confounding variables associated with the use of fluorescein that can confound physiologic interpretation of the VFP data.

8.2.2 Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) provides a panretinal measure of ocular anatomy from inferior to superior (or nasal to temporal) ora serrata and is not dependent upon the clarity of the ocular media. Therefore, optical distortions such as diabetic cataracts do not degrade MRI images. MRI has been successfully adapted to laboratory animal, as well as human, subjects, making it possible to conduct translational research between humans and a wide range of species including mice and rats (Fig. 8.2.1). In the mid to late 1980s, proof-of-concept principle with this technique was achieved in studies of mon-

8 I

Fig. 8.2.2. Schematic illustrating how the Gd-DTPA contrast agent is injected intravenously in a rodent. GdDTPA is distributed throughout the body, including the retina. In tissues with nonfenestrated blood vessels, such as the retina, Gd-DTPA is maintained inside the vascular space. The dotted arrows indicate that GdDTPA only leaks out of the circulation in the presence of damaged BRB. In this case, the presence of Gd-DTPA is readily detected by the vitreous water (Fig. 8.2.3)

keys and rabbits where damage to the blood ocular barriers was quantified using a non-fluorescein based method: dynamic contrast enhanced MRI (DCE-MRI) with gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA, 590 Da) [22, 48]. In this experiment, Gd-DTPA, also known as Gad, was injected intravenously and delivered by the blood supply to the retina (Fig. 8.2.2). Gd-DTPA is a relatively safe tracer to administer intravenously, has a plasma half-life of about 1.5 h, and, unlike fluorescein, Gad does not cause yellowing of the skin and urine [53, 54]. In addition, Gd-DTPA is freely diffusible (i.e., is a non-specific extracellular marker) and follows a well defined biexponential plasma decay (i.e., it is not bound to plasma protein and is excreted mainly by the kidneys) [53, 54]. Note that gadolini-

um can also be bound to larger molecules, such as albumin, if necessary [59] and that gadoliniumbased contrast agents are paramagnetic. Normally, Gd-DTPA does not penetrate non-fenestrated blood vessels or barriers, such as in the inner and outer BRB; thus the vitreous space remains unenhanced (Fig. 8.2.2) [8, 72]. However, when BRB becomes damaged, Gd-DTPA enters into the vitreous space via a passive diffusion mechanism. Gd-DPTA shortens the vitreous water spin-lattice (T1) relaxation time such that by collecting a T1 weighted image, the presence of Gd-DTPA can be readily detected as an increase (i.e., an enhancement) in signal intensity (Fig. 8.2.3). Alternatively, vitreous T1 can be measured but this is usually a relatively longer procedure than simply collecting a T1 weighted image. Another

approach, the quantification of increased intraretinal Gd-DTPA concentration, is considerably more difficult because at low spatial resolution plasma based-GD-DTPA cannot be easily distinguished from retinal tissue-only Gd-DTPA. Thus, most efforts have investigated changes in vitreous signal intensity following Gd-DTPA injection. Berkowitz et al. validated the use of DCE-MRI to sensitively and accurately measure BRB PS in rabbits and humans [8 – 10, 61, 62, 71]. In rabbits, grid photocoagulation was applied to inferior retina at different power levels (200, 400, 600, and 800 mW) producing progressively larger disruption of BRB that could be readily detected using DCE-MRI (Fig. 8.2.4) [8]. Vitreous signal intensities were measured at each time point and the initial change in signal intensity with time analyzed to produce a slope (Fig. 8.2.4) that could be interpreted as a measure of BRB “leakiness” and was correlated with laser power (Fig. 8.2.5) [8]. In humans, retinas of patients with proliferative diabetic retinopathy were examined by both FA and DCEMRI [71]. As shown in Fig. 8.2.6, the location and severity of enhancement, judged by visual inspection

of the images, corresponded to the fluorescein angiographic and/or clinical appearance of preretinal neovascularization.

Studies in the early 1990s demonstrated that the increase in vitreous signal intensity was linearly related to Gd-DTPA concentration (Fig. 8.2.3) [8, 9]. Knowing the Gd-DTPA vitreous level and the Gd-DTPA plasma concentration time course allows one to determine the extent of the leak in the retina, or, in other words, BRB PS [8, 9]. To calculate PS, the Simplified Early Enhancement method of Tofts and Berkowitz was used [9, 61]. This method requires estimates of the vitreous T1 in the absence of Gd-DTPA (T10), the relaxivity of Gd-DTPA (R1, s–1 mM–1), and the Gd-DTPA concentration plasma time course parameters [9, 61]. Vitreous T10 was previously reported to be approximately 3.5 s. This value has been verified in control rodents using a homogenous excitation and surface coil reception while collecting gradient recalled echo images at different flip angles. As expected for a T10 of approximately 3.5 s, a maximum vitreous signal intensity was found at a flip angle of 12°–13° (based on the

8 I

Fig. 8.2.5. Top graph: The relationship between the leakiness parameter (defined in Fig. 8.2.4) and the laser power setting described in Fig. 8.2.4 for the vitreous. Note that a similar analysis of signal intensity changes in the anterior chamber was also performed (not shown) and no discernible correlation was found [8]. Bottom graph: In a separate experiment we developed and applied the theory of converting the leakiness parameter into a measure of BRB PS. The accuracy and precision of this approach was investigated in rabbits pretreated with sodium iodate (30 mg/kg intravenously) and summarized here [9]. The MRI-derived PS normalized to the area of leaky retina (PS’) was compared to a similarly normalized PS calculated using a classical physiologic method and agreement was found between the two methods (P > 0.05). Furthermore, PS’ values in eyes with normal vitreous were not different (P > 0.05) compared with that from contralateral gas-compressed vitrectomized eyes (data not shown) [10]

Ernst angle formula, data not shown) [47]. GdDTPA relaxivity is constant at a set temperature and field strength and so the previously reported value of 4.5 s/mM was used [9]. To determine the pharmacokinetic parameters after a bolus of Gd-DTPA in rats, blood samples were obtained in separate experiments in heparinized tubes during the precontrast period, and 1, 3, 7, 15, 30, and 60 min postinjection. Following centrifugation, the plasma fraction was obtained for NMR analysis. Inversion recovery T1 experiments were performed on the water signal of the plasma fraction at room temperature. From the T1 value, the amount and thus concentration of Gd-DTPA was determined from a cali-

Fig. 8.2.6. Representative comparison of FA and DCE-MRI localization of BRB damage. Top panel: Early and late FA of a 41- year-old man with a 22-year history of insulin dependent diabetes (20/20 OD, 20/20 OS) and no history of photocoagulation. Bottom panel: Preand postcontrast administration of same patient in top panel. Note agreement in location and severity of enhancement on FA and DCE-MRI

bration curve obtained at room temperature in a separate phantom study. The unidirectional rate constant, k, is given by:

where D is the Gd-DTPA dose, Tk = TR exp(–TR/

T10)/(1 – exp(–TR/T10)), TR is the repetition time, a1,2 are the Gd-DTPA plasma amplitudes, and m1,2 are the