Macular Degeneration: Campochiaro PA

Campochiaro PA. · The Departments of Ophthalmology and Neuroscience, the Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9277, USA. · Drugs Today (Barc). · Pubmed #17925884 No free full text.

Abstract: Diseases of retinal and/or choroidal blood vessels are the most prevalent causes of moderate and severe vision loss in developed countries. Vascular endothelial growth factor (VEGF)-A plays a critical role in the pathogenesis of many of these diseases. Ranibizumab is a humanized antigen-binding fragment that binds all isoforms of VEGF-A. Intraocular injections of ranibizumab cause significant visual improvement in approximately 40% of patients with choroidal neovascularization due to age-related macular degeneration (AMD). Pilot trials have indicated that intraocular injections of ranibizumab also provide benefits in patients with macular edema due to diabetic retinopathy or retinal vein occlusions. Based upon several case series, bevacizumab, a full-length humanized monoclonal antibody that binds all isoforms of VEGF-A, improves vision in patients with choroidal neovascularization due to AMD and other diseases. Case series also suggest that bevacizumab can cause regression of retinal neovascularization in patients with proliferative diabetic retinopathy. Taken together, results with ranibizumab and bevacizumab suggest that potent antagonists of VEGF will provide the foundation of treatment for a wide variety of diseases complicated by retinal or choroidal neovascularization, or by excessive vascular leakage leading to macular edema.

Campochiaro PA. · Departments of Ophthalmology and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9277, USA. · J Cell Physiol. · Pubmed #17133346 No free full text.

Abstract: The elucidation of the molecular pathogenesis of a disease in animal models provides candidate targets for treatment. As specific antagonists for a target are developed and tested in clinical trials, if benefit is achieved, the candidate becomes a validated target. Validated targets stimulate additional research to identify optimal ways of attacking the target and studies in related disease processes to determine if the molecule is also a target in that context. Vascular endothelial growth factor (VEGF) has been identified as a validated target for several retinal vascular diseases. This has led to a flurry of activity resulting in beneficial treatments for patients and intensification of the search for other targets. This review summarizes preclinical and clinical trial results obtained with VEGF antagonists and describes evidence supporting the candidacy of other molecules currently being tested or soon to be tested for target status.

Campochiaro PA. · Department of Ophthalmology, The Johns Hopkins University School of Medicine, Maumenee 719, 600 N. Wolfe Street, Baltimore, MD 21287-9277, USA. · Expert Opin Biol Ther. · Pubmed #15335307 No free full text.

Abstract: Diseases complicated by vascular leakage and/or neovascularisation in the eye are responsible for the vast majority of visual morbidity and blindness in developed countries. The molecular signals that control vascular permeability and neovascularisation in the eye are being defined. Members of the vascular endothelial growth factor (VEGF) family are key stimulators that interact with two tyrosine kinase receptors, VEGF receptor (VEGFR)1 and 2; binding to two other receptors that lack tyrosine kinase activity, the neuropilins, is also important. Signalling through the VEGF pathway is modulated by the Tie2 receptor and its binding partners, the angiopoietins. Each of the participants in these two signalling pathways provides a potential target for intervention. Several proteins with antiangiogenic activity balance the stimulators and the outcome is determined by the net balance. Endostatin suppresses vascular permeability as well as ocular neovascularisation, suggesting that vascular leakage may also be regulated by counteracting proteins. Gene transfer provides a useful way to influence these balances. Clinical trials are underway to test whether these mechanisms can be translated into new therapies.

Vinores SA, Derevjanik NL, Vinores MA, Okamoto N, Campochiaro PA. · Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287-9289, USA. · Adv Exp Med Biol. · Pubmed #10949661 No free full text.

Abstract: Neovascularization (NV) causes visual deficits in ocular disorders such as diabetic retinopathy, age-related macular degeneration, and retinopathy of prematurity. An understanding of the angiogenic factors promoting this abnormal vascular growth is necessary to devise a therapeutic approach to inhibit NV. One factor known to promote NV is vascular endothelial growth factor (VEGF), which can also induce a breakdown of the blood-retinal barrier (BRB) leading to macular edema, another major cause of visual loss in a variety of ocular disorders. To investigate the role of VEGF on ocular NV, transgenic mice have been produced that over-express VEGF in the photoreceptors under control of the rhodopsin promoter. Eyes from these mice and from littermates not expressing the transgene were examined using immunohistochemistry, griffonia simplicifolia isolectin-B4 (GSA) staining to clearly visualize vessels, and electron microscopy. Levels of transgene expression were determined by the polymerase chain reaction. In normal mice, retinal vessels are organized into a superficial and a deep capillary bed with some vessels forming a shunt between both beds. In a transgenic line of mice that over-expresses VEGF (V-6), NV originates from the deep capillary bed at about postnatal day 10 (P10) and extends through the photoreceptor layer to form vascular complexes in the subretinal space with BRB breakdown occurring only in the area of NV. The superficial capillary bed and the choroidal vasculature are unaffected. In another line of transgenic mice with a higher expression rate of VEGF (V-24), photoreceptor degeneration begins at P7-8, soon after the onset of transgene expression, without widespread NV, as was observed in V-6 mice. In conclusion, overexpression of VEGF in transgenic mice is sufficient to cause retinal NV, but only the deep capillary bed is responsive. Increasing the expression of VEGF does not necessarily increase the amount of NV. A better understanding of the specific factors and conditions that result in a particular pattern of ocular NV may provide clues regarding the pathogenesis of ocular neovascular disease.

Vinores SA, Derevjanik NL, Ozaki H, Okamoto N, Campochiaro PA. · The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA. · Doc Ophthalmol. · Pubmed #10896335 No free full text.

Abstract: PURPOSE: To determine the mechanism of blood-retinal barrier (BRB) dysfunction in human and experimental specimens using immunocytochemistry. METHODS: Extravascular albumin was localized in clinical specimens and retinas from transgenic mice that overexpress vascular endothelial growth factor (VEGF) in the photoreceptors. Transgenic mouse retinas were also labeled with Griffonia simplicifolia isolectin-B4 (GSA), a lectin that binds to endothelial cells. RESULTS: The BRB is established by the presence of tight junctions between the retinal vascular endothelial (RVE) cells and the RPE cells and by a paucity of intraendothelial cell vesicles. When BRB breakdown occurs in human ocular disorders such as diabetic retinopathy, retinitis pigmentosa, or cystoid macular edema, staining for extravascular albumin reveals leakage through the tight junctions, an upregulation of intraendothelial vesicles, and permeation of RVE or RPE cells that have undergone degenerative changes. VEGF, in addition to inducing neovascularization (NV), promotes vascular leakage. In VEGF transgenic mice, BRB failure is confined to the outer retina, the area where NV occurs. GSA binds to the luminal and abluminal surfaces of RVE cells in new and established vessels and to intraendothelial vesicles and interendothelial cell junctions in areas of vascular leakage. CONCLUSION: BRB dysfunction may be mediated by leakage through the tight junctions of RVE or RPE cells, by trans-endothelial vesicular transport, or by permeation of RVE or RPE cells that have undergone degenerative changes. GSA may be a useful marker to assist in recognizing open tight junctions and an increase in intraendothelial cell vesicles, which are indicative of BRB failure.

Kent D, Vinores SA, Campochiaro PA. · Departments of Ophthalmology and Neuroscience, The Johns Hopkins University School of Medicine, Maumenee 719, 600 N Wolfe Street, Baltimore, MD 21287-9277, USA. · Br J Ophthalmol. · Pubmed #10781524 links to  free full text

This publication has no abstract.

Campochiaro PA, Soloway P, Ryan SJ, Miller JW. · The Departments of Ophthalmology and Neuroscience,The Johns Hopkins University School of Medicine, Baltimore, MD 21287-9277, USA. · Mol Vis. · Pubmed #10562658 links to  free full text

Abstract: Laser photocoagulation and several experimental treatments for choroidal neovascularization (CNV) in patients with age-related macular degeneration attempt to ablate the neovascularization, but do not address underlying angiogenic stimuli. As a result, recurrences are a major problem. Drug treatment to counter the growth of CNV would be a major advance, but its development is impeded by lack of knowledge concerning the stimuli and other molecular signals involved in the pathogenesis of CNV. Herein we explore clues that can be gleaned from clinical, epidemiological, pathological, and experimental data. These suggest that abnormalities of the extracellular matrix of retinal pigmented epithelial (RPE) cells may promote a pro-angiogenic RPE phenotype that contributes to the development of CNV. This provides a general hypothesis that can be tested, but it is also necessary to test hypotheses regarding the specific alterations in gene expression that contribute to CNV. Identification of alterations in gene expression will provide targets for rational design of drug treatment.

Do DV, Nguyen QD, Shah SM, Browning DJ, Haller JA, Chu K, Yang K, Cedarbaum JM, Vitti RL, Ingerman A, Campochiaro PA. · The Wilmer Eye Institute, 600 North Wolfe Street, Maumenee #719, Baltimore, MD 21287, USA. · Br J Ophthalmol. · Pubmed #19174400 No free full text.

Abstract: AIM: The aim of the study was to assess the safety and bioactivity of a single intravitreal injection of vascular endothelial growth factor (VEGF) Trap-Eye in subjects with diabetic macular oedema (DMO). METHODS: Five subjects with DMO, foveal thickness > or =250 microm measured by optical coherence tomography (OCT), and best-corrected visual acuity (BCVA) between 20/40 and 20/320, were enrolled. Each participant received a single intravitreal injection of 4.0 mg of VEGF Trap-Eye followed by a 6-week observation period. Outcome measures included safety and biological activity, including changes in BCVA and excess retinal thickness assessed by OCT. RESULTS: Injections of VEGF Trap-Eye were well tolerated with no ocular toxicity. One patient had an unrelated serious adverse event: hospitalisation for cellulitis of the left foot 27 days after injection of VEGF Trap-Eye. Median baseline BCVA was 36 ETDRS letters read at 4 m (not ETDRS visual acuity score; Snellen equivalent: 20/50) and median baseline excess central 1 mm foveal thickness (FTH) was 108 microm. At 4 weeks after injection, the median excess FTH was 59 microm and the median improvement in BCVA was nine letters. At 6 weeks after injection, four of the five patients showed improvement in excess FTH (median 74 microm; 31% reduction from baseline, p = 0.0625) and four of the five showed improvement in BCVA (median improvement of three letters). CONCLUSIONS: A single intravitreal injection of 4.0 mg of VEGF Trap-Eye was well tolerated and preliminary evidence of bioactivity was detected. These findings support additional studies investigating multiple injections of VEGF Trap-Eye in patients with DMO.

Nguyen QD, Shah SM, Hafiz G, Do DV, Haller JA, Pili R, Zimmer-Galler IE, Janjua K, Symons RC, Campochiaro PA. · Department of Ophthalmology, The Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA. · Am J Ophthalmol. · Pubmed #18054887 No free full text.

Abstract: PURPOSE: To investigate the safety, tolerability, and bioactivity of intravenous infusions of bevacizumab in patients with choroidal neovascularization (CNV) attributable to causes other than age-related macular degeneration. DESIGN: Nonrandomized clinical trial. METHODS: Ten patients with CNV received infusions of 5 mg/kg of bevacizumab. The primary efficacy outcome measure was change in visual acuity (VA; Early Treatment Diabetic Retinopathy Study letters read at 4 meters) at 24 weeks and secondary measures were changes from baseline in excess foveal thickness (center subfield thickness), area of fluorescein leakage, and area of CNV. RESULTS: Infusions were well tolerated and there were no ocular or systemic adverse events. At baseline, median VA was 25.5 letters read at 4 meters (20/80) and median foveal thickness was 346 mum. At the primary endpoint (24 weeks), median VA was 48.5 letters (20/32), representing four lines of improvement from baseline (P = .005), median foveal thickness was 248 mum representing a 72% reduction in excess foveal thickness (P = .007). Four of nine patients had complete elimination of fluorescein leakage, three had near complete elimination (reductions of 91%, 88%, and 87%), two had modest reductions, and one had no reduction. All patients except one showed a reduction in area of CNV with a median reduction of 43%. CONCLUSIONS: Despite the small number of patients studied, the marked improvement in VA accompanied by prominent reductions in foveal thickness, fluorescein leakage, and area of CNV suggest a beneficial effect. It may be worthwhile to consider further evaluation of systemic bevacizumab in young patients with CNV.

Shah SM, Tatlipinar S, Quinlan E, Sung JU, Tabandeh H, Nguyen QD, Fahmy AS, Zimmer-Galler I, Symons RC, Cedarbaum JM, Campochiaro PA. · Retinal Imaging Research and Reading Center, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9277, USA. · Invest Ophthalmol Vis Sci. · Pubmed #17122137 links to  free full text

Abstract: PURPOSE: In this study, the authors sought to develop and characterize techniques for measuring changes in choroidal neovascularization (CNV) lesion size and fluorescence over time for quantitative analysis of fluorescein angiograms. METHODS: Initial assessment of the quantitative technique was made by retrospectively analyzing digital fluorescein angiograms taken before and 3 months after photodynamic therapy (PDT) for CNV (6 patients, group 1). The method was then applied prospectively to digital fluorescein angiograms (baseline and day 71) obtained on 12 patients taking part in a clinical trial investigating the effect of vascular endothelial growth factor (VEGF) Trap in CNV (group 2). Two masked observers, with the use of image processing, measured the area of hyperfluorescence and fluorescence intensity above background. Values for each image were plotted against time after dye injection to generate curves, and each area under the curve (AUC) was calculated. RESULTS: The physician who treated the patients in group 1 judged the condition of three patients to be improved and of three to be worse 3 months after PDT. Masked retrospective grading of fluorescein angiograms showed an 11% decrease in AUC for fluorescence area and a 32% decrease in AUC for fluorescence intensity in the three patients whose conditions clinically improved but increases of 131% and 292% in the three patients whose conditions clinically worsened. In group 2, a 38% decrease in AUC for fluorescence intensity and a 19% decrease in AUC for fluorescence area were observed in patients who received VEGF Trap compared with increases of 66% (P = 0.004, Mann-Whitney U test) and 21% (P = 0.07) for patients who received placebo. Macular volume decreased by 11% in VEGF Trap-treated patients and increased by 10% in placebo-treated patients (P = 0.03). CONCLUSIONS: This study reports a technique for analysis of change in fluorescence area and intensity over time during fluorescein angiography (FA) using a continuous scale and its application in a clinical setting and a clinical trial. Compared with previous techniques making use of categorical scales, this approach provides an advantage for evaluating responses to treatment that may improve the value of FA as an outcome measure in clinical trials.

Nguyen QD, Tatlipinar S, Shah SM, Haller JA, Quinlan E, Sung J, Zimmer-Galler I, Do DV, Campochiaro PA. · The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9277, USA. · Am J Ophthalmol. · Pubmed #17046701 No free full text.

Abstract: PURPOSE: The role of vascular endothelial growth factor (VEGF) in diabetic macular edema (DME) was tested with ranibizumab, a specific antagonist of VEGF. DESIGN: A nonrandomized clinical trial. METHODS: Ten patients with chronic DME received intraocular injections of 0.5 mg of ranibizumab at baseline and at one, two, four, and six months. The primary outcome was change in foveal thickness between baseline and seven months, and the secondary outcome measures were changes from baseline in visual acuity and macular volume. RESULTS: Mean values at baseline were 503 microm for foveal thickness, 9.22 mm3 for macular volume, and 28.1 letters (20/80) read on an Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity chart. At seven months (one month after the fifth injection), the mean foveal thickness was 257 microm, which was a reduction of 246 microm (85% of the excess foveal thickness present at baseline; P = .005 by Wilcoxon signed-rank test for likelihood that this change is due to ranibizumab rather than chance). The macular volume was 7.47 mm3, which was a reduction of 1.75 mm3 (77% of the excess macular volume at baseline; P = .009). Mean visual acuity was 40.4 letters (20/40), which was an improvement of 12.3 letters (P = .005). The injections were well-tolerated with no ocular or systemic adverse events. CONCLUSION: Intraocular injections of ranibizumab significantly reduced foveal thickness and improved visual acuity in 10 patients with DME, which demonstrated that VEGF is an important therapeutic target for DME. A randomized, controlled, double-masked trial is needed to test whether intraocular injections of ranibizumab provide long-term benefit to patients with DME.

Nguyen QD, Shah SM, Hafiz G, Quinlan E, Sung J, Chu K, Cedarbaum JM, Campochiaro PA, Anonymous00330. · Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland MD 21287-9277, USA. · Ophthalmology. · Pubmed #16876249 No free full text.

Abstract: OBJECTIVES: To assess the safety, pharmacokinetics, and biological activity of IV administration of vascular endothelial growth factor trap (VEGF Trap), a recombinant protein containing the binding domains of VEGF receptors 1 and 2, in patients with neovascular age-related macular degeneration (AMD). DESIGN: Randomized, multicenter, placebo-controlled clinical trial. PARTICIPANTS: Twenty-five patients were enrolled (11 male, 14 female); 19 received VEGF Trap (0.3 [n = 7], 1.0 [n = 7], or 3.0 mg/kg [n = 5]), and 6 received a placebo. METHODS: Patients were randomized to receive a placebo or 0.3-, 1.0-, or 3.0-mg/kg VEGF Trap--a single IV dose followed by a 4-week observation period and then 3 doses 2 weeks apart. MAIN OUTCOME MEASURES: Safety and biological activity, including change in excess retinal thickness and volume assessed by optical coherence tomography and visual acuity (VA) measured by the Early Treatment Diabetic Retinopathy Study protocol. RESULTS: The majority of adverse events attributable to VEGF Trap were mild to moderate in severity, but 2 of 5 patients treated with 3.0 mg/kg experienced dose-limiting toxicity (1 with grade 4 hypertension and 1 with grade 2 proteinuria); therefore, all patients in the 3.0 mg/kg-dose group were withdrawn from the study. The mean percent changes in excess retinal thickness were -12%, -10%, -66%, and -60%, respectively, for the placebo and 0.3-, 1.0-, and 3.0-mg/kg groups at day 15 (P<0.02 by analysis of covariance [ANCOVA]) and -5.6%, +47.1%, and -63.3% for the placebo and 0.3- and 1.0-mg/kg groups at day 71 (P<0.02, ANCOVA). A significant change in VA was not noted in this small study. CONCLUSIONS: The maximum tolerated dose of IV VEGF Trap in this study population was 1.0 mg/kg. This dose resulted in elimination of about 60% of excess retinal thickness after either single or multiple administrations. Alternative routes of delivery to increase the therapeutic window are being explored.

Campochiaro PA, Nguyen QD, Shah SM, Klein ML, Holz E, Frank RN, Saperstein DA, Gupta A, Stout JT, Macko J, DiBartolomeo R, Wei LL. · Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. · Hum Gene Ther. · Pubmed #16454650 No free full text.

Abstract: Twenty-eight patients with advanced neovascular age-related macular degeneration (AMD) were given a single intravitreous injection of an E1-, partial E3-, E4-deleted adenoviral vector expressing human pigment epithelium- derived factor (AdPEDF.11). Doses ranging from 10(6) to 10(9.5) particle units (PU) were investigated. There were no serious adverse events related to AdPEDF.11 and no dose-limiting toxicities. Signs of mild, transient intraocular inflammation occurred in 25% of patients, but there was no severe inflammation. Six patients experienced increased intraocular pressure that was easily controlled by topical medication. All adenoviral cultures were negative. At 3 and 6 months after injection, 55 and 50%, respectively, of patients treated with 10(6)-10(7.5) PU and 94 and 71% of patients treated with 10(8)-10(9.5) PU had no change or improvement in lesion size from baseline. The median increase in lesion size at 6 and 12 months was 0.5 and 1.0 disk areas in the low-dose group compared with 0 and 0 disk areas in the high-dose group. These data suggest the possibility of antiangiogenic activity that may last for several months after a single intravitreous injection of doses greater than 10(8) PU of AdPEDF.11. This study provides evidence that adenoviral vector-mediated ocular gene transfer is a viable approach for the treatment of ocular disorders and that further studies investigating the efficacy of AdPEDF.11 in patients with neovascular AMD should be performed.

Campochiaro PA, Anonymous00296. · Departments of Ophthalmology and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA. · Invest Ophthalmol Vis Sci. · Pubmed #14985312 links to  free full text

Abstract: PURPOSE: To evaluate the efficacy and safety of PKC412, an orally administered kinase inhibitor, in subjects with diabetic macular edema. METHODS: This was a randomized (1:1:1:1), multicenter, double-masked, parallel-group study in which subjects (n = 141) received placebo or PKC412 (50, 100, or 150 mg/d) for up to 3 months. Subjects were 18 to 85 years of age and had retinal thickening that met predefined criteria and best corrected visual acuity of 55 letters or more. Efficacy was based on changes in retinal thickening measured by grading of fundus photographs and optical coherence tomography (OCT) and changes in visual acuity. RESULTS: Grading of fundus photographs showed a statistically significant decrease in the area of greatest retinal thickening in patients receiving 150 mg/d of PKC412 (P = 0.032). OCT demonstrated that the two higher doses of PKC412 caused a significant decrease in thickening in the region of greatest thickening and in the fovea (P < or = 039), with response in the high-dose group significantly different from that in the placebo group (difference = -66.69 micro m [95.2% CI: -128.57 to -4.81]; P = 0.030). Retinal volume for all locations also showed a significant decrease from baseline in the 100- and 150-mg/d PKC412 groups (P < or = 004), and the 150-mg/kg group showed significantly less retinal volume than the placebo group at 3 months (difference = -0.46 mm(3) [95.2% CI: -0.86-0.06]; P = 0.019). There was a small (4.36 letters), but significant (P = 0.007), improvement in visual acuity at 3 months compared with baseline in the 100-mg/d PKC412 group. Gastrointestinal side effects (diarrhea, nausea, and vomiting) were the most common adverse events attributed to the drug. Dose-related effects were observed for tolerability, glycemic control, and liver toxicity. CONCLUSIONS: Orally administered PKC412 at doses of 100 mg/d or higher may significantly reduce macular edema and improve visual acuity in diabetic subjects. However, concern regarding liver toxicity with systemic therapy makes local delivery an appealing approach.

Nguyen QD, Shah SM, Van Anden E, Sung JU, Vitale S, Campochiaro PA. · Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9277, USA. · Invest Ophthalmol Vis Sci. · Pubmed #14744906 links to  free full text

Abstract: PURPOSE: Diabetic macular edema (DME) is the most common cause of moderate visual disability in persons of working age in the United States. The pathogenesis of DME is poorly understood. In this study, the effect of retinal hypoxia in the development and maintenance of DME was investigated. METHODS: Five patients with chronic DME despite at least one focal laser photocoagulation treatment (nine eyes) received 4 L/min of inspired oxygen by nasal cannula for 3 months. Best corrected visual acuity (VA) and retinal thickness, assessed by optical coherence tomography (OCT), were measured at baseline, during 3 months of oxygen treatment, and for 3 months after stopping oxygen. RESULTS: After 3 months of oxygen therapy, nine of nine eyes with DME at baseline showed a reduction in thickness of the center of the macula. Foveal thickness (FTH) above the normal range was reduced by an average of 43.5% (range, 14%-100%), excess foveolar thickness (CEN) was reduced by an average of 42.1% (range, 13%-100%), and excess macular volume was reduced by an average of 54% (range, 35%-100%). Statistical analyses suggested that these changes were unlikely to be due to chance (P = 0.0077 by Wilcoxon signed-rank test). Three eyes showed improvement in VA by at least 2 lines, one by slightly less than 2 lines, and five eyes showed no change. Three months after discontinuation of oxygen, five of the nine eyes showed increased thickening of the macula compared with when oxygen was discontinued. CONCLUSIONS: Supplemental inspired oxygen may decrease macular thickness due to DME, suggesting that retinal hypoxia is involved in the development and maintenance of DME.

Guaiquil V, Swendeman S, Yoshida T, Chavala S, Campochiaro PA, Blobel CP. · Arthritis and Tissue Degeneration Program, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA. · Mol Cell Biol. · Pubmed #19273593 No free full text.

Abstract: Pathological ocular neovascularization, caused by diabetic retinopathy, age-related macular degeneration, or retinopathy of prematurity, is a leading cause of blindness, yet much remains to be learned about its underlying causes. Here we used oxygen-induced retinopathy (OIR) and laser-induced choroidal neovascularization (CNV) to assess the contribution of the metalloprotease-disintegrin ADAM9 to ocular neovascularization in mice. Pathological neovascularization in both the OIR and CNV models was significantly reduced in Adam9(-/-) mice compared to wild-type controls. In addition, the level of ADAM9 expression was strongly increased in endothelial cells in pathological vascular tufts in the OIR model. Moreover, tumor growth from heterotopically injected B16F0 melanoma cells was reduced in Adam9(-/-) mice compared to controls. In cell-based assays, the overexpression of ADAM9 enhanced the ectodomain shedding of EphB4, Tie-2, Flk-1, CD40, VCAM, and VE-cadherin, so the enhanced expression of ADAM9 could potentially affect pathological neovascularization by increasing the shedding of these and other membrane proteins from endothelial cells. Finally, we provide the first evidence for the upregulation of ADAM9-dependent shedding by reactive oxygen species, which in turn are known to play a critical role in OIR. Collectively, these results suggest that ADAM9 could be an attractive target for the prevention of proliferative retinopathies, CNV, and cancer.

Dong A, Xie B, Shen J, Yoshida T, Yokoi K, Hackett SF, Campochiaro PA. · Departments of Ophthalmology and Neuroscience, Johns Hopkins, University School of Medicine, Baltimore, Maryland, USA. · J Cell Physiol. · Pubmed #19142872 No free full text.

Abstract: Mice deficient in superoxide dismutase 1 (Sod1(-/-) mice) develop many features seen in patients with age-related macular degeneration (AMD) including choroidal neovascularization (NV). We sought to determine if the absence of SOD1 contributes to the pro-angiogenic environment in the subretinal space or whether it is completely secondary to other changes in Bruch's membrane and the retinal pigmented epithelium (RPE) that precede the development of choroidal NV. In an ischemic retinopathy model or a transgenic model in which the rhodopsin promoter drives expression of vascular endothelial growth factor (VEGF) in photoreceptor there was significantly more NV in Sod1(-/-) compared to Sod1(+/+) mice. The compromised antioxidant defense system in Sod1(-/-) mice contributes to the pro-angiogenic environment, because treatment of Sod1(-/-) mice with a mixture of antioxidants caused a significant reduction in ischemia-induced retinal NV. Wild-type mice treated with the same antioxidants also showed reduced ischemia-induced retinal NV, reduced VEGF-induced subretinal NV, and reduced choroidal NV at Bruch's membrane rupture sites. These data suggest that reactive oxygen species contribute to several types of ocular NV. This could explain why in the Age-Related Eye Disease Trial, antioxidant treatment reduced conversion from non-neovascular to neovascular AMD and severe vision loss, and suggest that potent antioxidants should be considered for other diseases complicated by ocular NV. J. Cell. Physiol. 219: 544-552, 2009. (c) 2009 Wiley-Liss, Inc.

Kiuchi K, Matsuoka M, Wu JC, Lima e Silva R, Kengatharan M, Verghese M, Ueno S, Yokoi K, Khu NH, Cooke JP, Campochiaro PA. · Department of Ophthalmology, The Johns Hopkins University of Medicine, Baltimore, MD 21287-9277, USA. · Invest Ophthalmol Vis Sci. · Pubmed #18385094 links to  free full text

Abstract: PURPOSE: Nicotinic acetylcholine receptors (nAChR) are best known for their role in neurotransmission, but they have recently been demonstrated on vascular endothelial cells. Acetylcholine is their endogenous ligand, but they are also stimulated by nicotine. By stimulating nAChR, nicotine promotes tumor angiogenesis as well as atherosclerotic plaque neovascularization. In this study, the authors investigated the role of nAChR in the pathogenesis of choroidal neovascularization (CNV). METHODS: The effect of the nonselective nAChR antagonist mecamylamine was tested on human retinal and choroidal endothelial cells in vitro and in a murine model of CNV. RESULTS: Several nAChR isoforms were identified in retinal and choroidal microvascular endothelial cells, and the ability of these cells to form tubules when grown in growth factor-reduced basement membrane matrix and supplemented with VEGF was suppressed by the nAChR antagonist mecamylamine. Supplementation of the drinking water of mice with nicotine increased the size of CNV lesions at Bruch membrane rupture sites, an effect that was blocked by subcutaneous administration of mecamylamine (50 mg/kg/d) by an osmotic pump. In the absence of nicotine, CNV formation was suppressed by the infusion of 50 mg/kg/d mecamylamine or by topical application 0.1 or 1% mecamylamine to the cornea. CONCLUSIONS: These data suggest that endogenous activation of nAChR promotes CNV and that activation of nAChR by nicotine may contribute to the increased incidence of CNV seen in smokers with age-related macular degeneration (AMD). Topically administered mecamylamine could provide an appealing new treatment approach for CNV.

Campochiaro PA, Hafiz G, Shah SM, Nguyen QD, Ying H, Do DV, Quinlan E, Zimmer-Galler I, Haller JA, Solomon SD, Sung JU, Hadi Y, Janjua KA, Jawed N, Choy DF, Arron JR. · Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9277, USA. · Mol Ther. · Pubmed #18362932 No free full text.

Abstract: Macular edema is a major cause of vision loss in patients with central retinal vein occlusion (CRVO) or branch retinal vein occlusion (BRVO). It is not clear how much of the edema is due to hydrodynamic changes from the obstruction and how much is due to chemical mediators. Patients with macular edema due to CRVO (n = 20) or BRVO (n = 20) were randomized to receive three monthly injections of 0.3 or 0.5 mg of ranibizumab. At the primary endpoint, month 3, the median improvement in letters read at 4 m was 17 in the 0.3-mg group and 14 in the 0.5-mg group for CRVO, and 10 and 18, respectively for the BRVO group. Optical coherence tomography (OCT) showed that compared to injections of 0.3 mg, injections of 0.5 mg of ranibizumab tended to cause more rapid reductions of central retinal thickening that lasted longer between injections, but in 3 months, excess central retinal thickening which is a quantitative assessment of the macular edema, was reduced by approximately 90% in all four treatment groups. There was no correlation between the amount of improvement and duration of disease or patient age at baseline, but there was some correlation between the aqueous vascular endothelial growth factor (VEGF) level at baseline and amount of improvement. These data indicate that excess production of VEGF in the retinas of patients with CRVO or BRVO is a major contributor to macular edema and suggest that additional studies investigating the efficacy of intraocular injections of ranibizumab are needed.

Doukas J, Mahesh S, Umeda N, Kachi S, Akiyama H, Yokoi K, Cao J, Chen Z, Dellamary L, Tam B, Racanelli-Layton A, Hood J, Martin M, Noronha G, Soll R, Campochiaro PA. · TargeGen, Inc., San Diego, California. · J Cell Physiol. · Pubmed #18330892 No free full text.

Abstract: Age-related macular degeneration, diabetic retinopathy, and retinal vein occlusions are complicated by neovascularization and macular edema. Multi-targeted kinase inhibitors that inhibit select growth factor receptor tyrosine kinases and/or components of their down-stream signaling cascades (such as Src kinases) are rationale treatment strategies for these disease processes. We describe the discovery and characterization of two such agents. TG100572, which inhibits Src kinases and selected receptor tyrosine kinases, induced apoptosis of proliferating endothelial cells in vitro. Systemic delivery of TG100572 in a murine model of laser-induced choroidal neovascularization (CNV) caused significant suppression of CNV, but with an associated weight loss suggestive of systemic toxicity. To minimize systemic exposure, topical delivery of TG100572 to the cornea was explored, and while substantial levels of TG100572 were achieved in the retina and choroid, superior exposure levels were achieved using TG100801, an inactive prodrug that generates TG100572 by de-esterification. Neither TG100801 nor TG100572 were detectable in plasma following topical delivery of TG100801, and adverse safety signals (such as weight loss) were not observed even with prolonged dosing schedules. Topical TG100801 significantly suppressed laser-induced CNV in mice, and reduced fluorescein leakage from the vasculature and retinal thickening measured by optical coherence tomography in a rat model of retinal vein occlusion. These data suggest that TG100801 may provide a new topically applied treatment approach for ocular neovascularization and retinal edema.

Dong A, Shen J, Krause M, Hackett SF, Campochiaro PA. · Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9277, USA. · J Neurochem. · Pubmed #17935603 No free full text.

Abstract: Oxidative damage contributes to retinal cell death in patients with age-related macular degeneration or retinitis pigmentosa. One approach to treatment is to identify and eliminate the sources of oxidative damage. Another approach is to identify treatments that protect cells from multiple sources of oxidative damage. In this study, we investigated the effect of increased expression of glial cell line-derived neurotrophic factor (GDNF) in three models of oxidative damage-induced retinal degeneration. Double transgenic mice with doxycycline-inducible expression of GDNF in the retina were exposed to paraquat, FeSO(4), or hyperoxia, all sources of oxidative damage and retinal cell death. Compared to controls, mice with increased expression of GDNF in the retina showed significant preservation of retinal function measured by electroretinograms, reduced thinning of retinal cell layers, and fewer TUNEL-positive cells indicating less retinal cell death. Mice over-expressing GDNF also showed less staining for acrolein, nitrotyrosine, and 8-hydroxydeoxyguanosine, indicating less oxidative damage to lipids, proteins, and DNA. This suggests that GDNF did not act solely to allow cells to tolerate higher levels of oxidative damage before initiation of apoptosis, but also reduced damage from oxidative stress to critical macromolecules. These data suggest that gene transfer of Gdnf should be considered as a component of therapy for retinal degenerations in which oxidative damage plays a role.

Ghazi NG, Ciralsky JB, Shah SM, Campochiaro PA, Haller JA. · Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland 21287, USA. · Am J Ophthalmol. · Pubmed #17869207 No free full text.

Abstract: PURPOSE: To assess the optical coherence tomography (OCT) characteristics of eyes with persistent clinically significant diabetic macular edema (PDME) after focal laser treatment, with emphasis on the vitreomacular interface (VMI) characteristics. DESIGN: Prospective, observational case series. METHODS: Fifty eyes with PDME after at least one focal laser treatment were enrolled prospectively. Slit-lamp biomicroscopy, stereoscopic fundus photography, fluorescein angiography (FA), and OCT were performed for each eye. The main outcome measures included the detection rate of VMI abnormalities (VMIA) by OCT in comparison with biomicroscopy, fundus photography, and FA (traditional techniques); the relationship between VMIA and the number of focal laser sessions per eye and FA leakage pattern. RESULTS: Two of 50 eyes were excluded because of incomplete data. For the remaining 48 eyes, 25 eyes (52.1%) demonstrated definite VMIA, including anomalous vitreal adhesions, epiretinal membrane (ERM), or both, and six eyes (12.5%) had questionable VMIA. OCT in general was 1.94 times more sensitive than traditional techniques combined in detecting VMIA (P = .00003). The number of focal laser sessions and diffuse FA leakage were not associated with an increased prevalence of VMIA (P = .13 and P = .47, respectively). CONCLUSIONS: This study demonstrates a high prevalence of VMIA in eyes with PDME after focal laser treatment and underscores the superiority of OCT in detecting these abnormalities. OCT evaluation of eyes with PDME may be helpful in identifying VMIA, which may impact treatment selection and patient subgroup stratification.

Shen JK, Dong A, Hackett SF, Bell WR, Green WR, Campochiaro PA. · The Department of Ophthalmology, The Johns Hopkins University School of Medicine Maumenee, Baltimore, Maryland 21287-9277, USA. · Histol Histopathol. · Pubmed #17701910 No free full text.

Abstract: Epidemiologic studies have suggested that elderly patients who consumed diets rich in antioxidants throughout their lives are less likely to be afflicted with age-related macular degeneration (AMD). This led to the Age-Related Eye Disease Study, which showed that supplements containing antioxidant vitamins and zinc reduce the risk of progression to severe stages of AMD. Despite these data that indirectly implicate oxidative damage in the pathogenesis of AMD, there has not been any direct demonstration of increased oxidative damage in the retinas of patients with AMD. In this study, we used biomarkers of oxidative damage in postmortem eyes from patients with AMD and comparably aged patients without AMD to directly assess for oxidative damage. Sections from 4 eyes with no pathologic features of AMD showed no immunofluorescent staining for markers of oxidative damage, while sections from 8 of 12 eyes with advanced geographic atrophy showed evidence of widespread oxidative damage in both posterior and anterior retina. Only 2 of 8 eyes with choroidal neovascularization and 2 of 16 eyes with diffuse drusen and no other signs of AMD showed evidence of oxidative damage. These data suggest that widespread oxidative damage occurs in the retina of some patients with AMD and is more likely to be seen in patients with advanced geographic atrophy. This does not rule out oxidative damage as a pathogenic mechanism in patients with CNV, but suggests that a subpopulation of patients with geographic atrophy may have a major deficiency in the oxidative defense system that puts the majority of cells in the retina at risk for oxidative damage.

Tatlipinar S, Shah SM, Campochiaro PA, Nguyen QD. · Retina Service, Wilmer Eye Institute, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA. · Ophthalmologica. · Pubmed #17579287 No free full text.

Abstract: AIM: To assess the intraobserver repeatability of automated versus adjusted optical coherence tomography (OCT) measurements in patients with neovascular age-related macular degeneration (NVAMD). METHODS: Ten eyes with NVAMD from 10 consecutive patients underwent two OCT measurements within 5 days by a single operator. Automated and adjusted central 1-mm foveal thickness and automated and adjusted total macular volume were measured in each study eye. The term 'adjusted' refers to manually corrected values, in which the interface landmarks for measurements are selected by the operator using Stratus scan profiling and custom software. Bland-Altman method and bootstrap comparison of intraclass correlations (ICCs) were used for repeatability analysis. RESULTS: Bland-Altman comparison did not reveal any statistically significant difference in any parameter, when results at first and second examination were compared (p > 0.05), indicating that the repeated measurements are similar. Further analysis was conducted using the bootstrap comparison of ICCs. The difference between adjusted and automated foveal thickness ICCs (r = 0.945 and 0.635, respectively) was significant (p = 0.031), indicating higher repeatability for adjusted foveal thickness. The ICCs for adjusted and automated total macular volume (r = 0.873 and 0.863, respectively) showed no statistically significant difference (p = 0.881). CONCLUSION: The repeatability of adjusted retinal thickness measurements, in which the errors of retinal boundary detection by OCT analysis software is corrected by the operator using scan profiling, is found to be higher than that of automated ones in this small group of NVAMD patients when performed by a single experienced operator.

Do DV, Cho M, Nguyen QD, Shah SM, Handa JT, Campochiaro PA, Zimmer-Galler I, Sung JU, Haller JA. · Retina Division, The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA. · Retina. · Pubmed #17558315 No free full text.

Abstract: PURPOSE: To compare retina surgeons' recommendations for management of epiretinal membranes (ERM) and vitreomacular traction (VMT) based on clinical assessment alone with management based on clinical evaluation supplemented by optical coherence tomography (OCT). METHODS: A prospective, masked clinical case series was conducted. Surgeons first performed a complete history and physical examination on patients referred with the macular disorders under study without the benefit of adjunctive OCT, determined whether ERM, VMT, and/or macular edema were present, questionably present, or absent, and made a provisional management recommendation. The retina specialists then reviewed the OCT images for the presence or absence of ERM, VMT, and/or associated macular edema and reconsidered the final management recommendation in light of clinical evaluation combined with OCT findings. RESULTS: Eighty-four eyes of 73 patients were examined. ERM was identified in 66 (78.6%) of 84 eyes using clinical examination compared with 72 (85.7%) of 84 eyes using OCT (P = 0.06). VMT was identified in 5 (6%) of 84 eyes using clinical examination compared with 18 (21.4%) of 84 eyes using OCT (P < 0.005). Macular edema was identified in 57 (67.9%) of 84 eyes using clinical examination compared with 70 (83.3%) of 84 eyes using OCT (P = 0.003). Surgical intervention was recommended in 33 cases: 19 (57.6%) based on the history and clinical examination findings without OCT information and an additional 14 (42.4%) based on the combination of clinical evaluation and OCT findings. CONCLUSIONS: OCT is more sensitive than clinical examination in detecting ERM, VMT, and associated macular edema. Taken together with careful clinical evaluation, OCT findings influenced surgeons to recommend consideration of surgery to an additional 14 patients (42.2%) in this series.