title: Periocular triamcinolone enhances intraocular gene expression after delivery by adenovirus.
abstract: OBJECTIVE
  A noninvasive imaging technique was used for serial assessment of gene expression after intraocular gene transfer. Bioluminescence after intravitreous administration of an adenovirus vector containing the firefly luciferase gene was measured serially and noninvasively. The optical signal was then used as a bioassay to determine whether periocular immune modulation affects intraocular transgene expression.
  
  
  METHODS
  Sixty-two, 8-week-old, male BALB/c mice were used. The correlation of optical signal intensity was determined by tissue luciferase level after injecting 30 mice with one of three intravitreous doses of Ad-Luc-GFP (10(8), 5 x 10(8), or 10(9) particles in 1 microL). Ocular bioluminescence was measured at days 2, 5, 8, and 14. The bioluminescence was then directly compared with measured tissue luciferase levels. The remaining 32 mice were divided into two groups. One group (n = 16), was injected with periocular corticosteroid (400 mug in 10 microL). Two days later, Ad-Luc-GFP was administered by intravitreous injection (10(9) particles in 1 microL). The remaining mice (n = 16) were injected with the same dose of intravitreous Ad-Luc-GFP without corticosteroid pretreatment. Ocular bioluminescence was then assessed longitudinally on days 2, 4, 6, 8, 11, 14, 22, and 30 after intravitreous injection in n = 10 mice per group. The optical signal intensity in each group was compared over the study period. The remaining 12 mice (n = 6, each group) were used to assess histologic differences between the two groups.
  
  
  RESULTS
  In vivo measurement of ocular bioluminescence was well correlated with tissue luciferase levels (Spearman's correlation, r = 0.969, P < 0.001). Periocular TA injection markedly decreased the acute inflammatory reaction associated with intravitreous Ad-Luc-GFP and was associated with a significant increase in the duration of peak luciferase expression as well as the total period of luciferase expression.
  
  
  CONCLUSIONS
  A significant enhancement of intraocular transgene expression is associated with periocular pretreatment with corticosteroid. Histologic evidence of immune cell reduction in ocular tissues in corticosteroid-treated eyes implies a local immune response. Periocular treatment with corticosteroids may enhance adenovirus-mediated gene expression in the eye.
authors.affiliation: Department of Ophthalmology, Johns Hopkins University School of Medicine, 1550 Orleans Street, Baltimore, MD 21287, USA.
authors.forename: Choul Yong
authors.initials: CY
authors.lastname: Park
authors.forename: Roy S
authors.initials: RS
authors.lastname: Chuck
authors.forename: Marisol
authors.initials: M
authors.lastname: Cano
authors.forename: Margaret
authors.initials: M
authors.lastname: Yew
authors.forename: Viet
authors.initials: V
authors.lastname: Nguyen
authors.forename: Jack
authors.initials: J
authors.lastname: Parker
authors.forename: Keisuke
authors.initials: K
authors.lastname: Mori
authors.forename: Peter L
authors.initials: PL
authors.lastname: Gehlbach
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D003228:Conjunctiva / Q000187:drug effects; D003952:Diagnostic Imaging; D005123:Eye / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects*; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D005938:Glucocorticoids / Q000494:pharmacology*; D049452:Green Fluorescent Proteins / Q000235:genetics*; D007267:Injections; D049409:Luciferases, Firefly / Q000235:genetics*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011993:Recombinant Fusion Proteins / Q000235:genetics*; D019076:Transgenes; D014222:Triamcinolone Acetonide / Q000494:pharmacology*; D014822:Vitreous Body
chemical_list: D005938:Glucocorticoids; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D049409:Luciferases, Firefly; D014222:Triamcinolone Acetonide