Transcript PURPOSE Novel hydrogel bandage and eye

Evaluation of Hydrogel Bandage and EyeContact Devices for HSV-1-Glycoprotein-D
Delivery Against Keratitis Formation in
Rabbit Ocular Herpes
Christian Clement, PhD, MPhil1,a, Author
Vaibhav Tiwari, PhD2, Co-Author
Hilary W. Thompson, PhD2 1,3-6, Co-Author
Departments of 1Ophthalmology, 3Pharmacology, 4Microbiology, 5Neuroscience Center, 6School of Public
Health Biostatistics, Center of Excellence, Louisiana State University Health Sciences Center School of
Medicine, New Orleans, LA; 2College of Osteopathic Medicine of the Pacific, Western University of
Health Sciences, Pomona, CA
Financial Disclosure
a Ocular Therapeutix, Inc. Travel Support
Resure™ Adherent Ocular Bandage (novel hydrogel bandage) is a courtesy of Ocular Therapeutix, Inc.,
Bedford, MA.
Potential corneal toxicity to ReSure™-not assessed as it is CE Mark approved for use in Europe and is
investigational in the U.S.
This study was presented in part at the AAO-MEACO October 16-19, 2010 Chicago, IL
PURPOSE
Novel hydrogel bandage and eye-contact devices for drug
delivery and as physical protective barrier
1. To evaluate the course of corneal lesions and keratitis
formation in eyes of rabbits infected with herpes simplex
virus type-1 (HSV-1) and treated with an in-situ forming
hydrogel bandage, contact-lens and collagen-soft-shield
each containing HSV-1 glycoprotein D (gD) added to block
virus infection sites as antiviral-replication strategy
2. Reduction of Pseudomonas aeruginosa keratitis in a
rabbit keratotomy model by novel hydrogel bandage
(AAO 2010-PO041) has been summarized.
PURPOSE continued
Strategy of delivering crucial viral protein to eye
surface to prevent infection
HSV-1 virus has a
glycoprotein, gD which it
uses to physically bind to coreceptors on the surface of
cells/tissues in infection. We
expressed the non viral
protein (61KDa) and added
this ligand at ~10
nanograms/µl to hydrogel
bandage and eye-contact
devices for delivery to
corneal surface to prevent
actual infectious virus from
binding and infecting.
Confocal microscopy showing
actual HSV-1 gD (red) physically
bound to cell surface receptor
(green) during viral infection
process. Courtesy V. Tiwari et al
FEBS letters 581 (2007) 4468-4472.
Constituents of Novel Hydrogel
Bandage
The novel hydrogel bandage, supplied in
separate syringes is reconstituted as liquid
preceding gelation. The novel hydrogel
bandage is composed of 3 components all of
which have a long history of safe ophthalmic
use- polyethylene glycol, trilysine, and a pHbalanced aqueous accelerator solution.
Novel hydrogel bandage use- Six
simple steps
1.
Two syringes are attached
4.
Accelerator added to drop of
solution
2.
Powder + diluent mixed
5.
Two drops mixed with singleuse applicator
3.
Drop of solution colored blue
(for visual aid) dispensed
6.
Droplets applied to ocular
surface within less than 25
seconds.
MATERIALS AND METHODS
(Herpetic keratitis)
• A prospective nonrandomized comparative study.
• 16 NZW rabbits of the same age and in 4 groups (hydrogel bandage,
Acuvue® contact-lens, Oasis® soft-collagen-shield and Untreated).
• Corneas were each scarified and separate inoculations done with
2x105 PFU of infectious HSV-1, 17Syn+.
• Initial slit-lamp examination (SLE) was at post infection (PI) day 2
followed by applying on eyes HSV-1-gD impregnated, bandage, other
contact devices secured by partial tarsorrhaphy , and untreated.
• All eyes were scored by SLE for appearance of corneal lesions and
corneal opacity from PI day 3 to PI day 28 (graded scale: 0, no
opacity; 1, mild cloudiness with visible iris; 2, moderate cloudiness
with obscured iris; 3, total corneal cloudiness with invisible iris and 4,
total opacity with no posterior view).
MATERIALS AND METHODS
(Pseudomonas Keratitis)
• A prospective nonrandomized comparative study.
• 16 NZW rabbits of the same age and in 4 groups.
• Keratotomy was performed on 1 eye of all rabbits by making cuts
to the right central corneas (cross incisions, 5x5mm; depth,
0.2mm).
• Control (8 eyes), P. aeruginosa-soaked collagen shield was placed
over the incision.
• Experimental (8 eyes), novel hydrogel bandage was applied before
P. aeruginosa-soaked collagen shield placed over the incision.
• All collagen shields were secured by partial tarsorrhaphy and
remained in place for 20 or 44 hours.
• CFU were determined by plating 10-fold serial dilutions of
homogenized corneas surgically removed from euthanized rabbits.
RESULTS
(Herpetic keratitis)
HSV-1 gD delivery by novel hydrogel bandage and eye-contact devices
Hydrogel bandage-gD treated eye,
average score 0.5, no detectable keratitis
Lens-gD treated eye, average
score 2.0, mild keratitis
RESULTS continued
(Herpetic keratitis)
Shield-gD treated eye, average score 3.5,
with keratitis and corneal neovascularization
Untreated eye, average score 4.0,
with severe keratitis and corneal
neovascularization
RESULTS continued
(Pseudomonas keratitis)
Novel hydrogel bandage treated versus untreated eyes
Infected-treated eye (44
hours), substantial
protection against
inflammatory and
bacterial infiltration in
cut area
Infected-untreated eye
(20 hours), engulfment
of cornea by discharge
and exudates
Infected-untreated eye (44
hours), inflammation,
injection (arrow) and
friable neovascularization
(arrowhead)
Colony forming units/mL in novel hydrogel
bandage treated versus untreated eyes
Mean CFU/mL from
treated and
untreated eyes after
20 or 44 hours
incubation with
bacteria-soaked
collagen shields.
Test condition
Mean CFU/mL
% change
p value
7.85 ± 3.64 x 106
+19%
0.1730
0.86 ± 0.24 x 106
-77%
0.0336
20 h
44 h
Control
6.6 ± 0.47 x 106
Hydrogel bandage
3.7 ± 1.24 x 106
Comparison of CFU/mL, treated and untreated eyes across
post-infection time points.
DISCUSSION AND CONCLUSION
•
•
Incisions to the eye are conduit for infection.
In general use of natural molecules (proteins) to bind and block sites on and within
cells/tissues that facilitate pathogen entry are complicated.
•
Novel hydrogel bandage treated corneas exhibited significant protection against pathogen
entry.
•
Novel hydrogel bandage and contact lens delivered viral protein gD which protected
incisions from acting as sites for pathogen exploitation for establishment of infection.
•
Novel hydrogel bandage applied over wounds in rabbit corneas, also protected against P.
aeruginosa infection.
•
Novel hydrogel bandage and contact lens could successfully be modified for healing
surgical wounds in grafting and penetrating keratoplasties and could be ideal for lowering
the risk of bacterial infection in cataract surgeries and vitrectomies.