Association Between Torque Teno Virus and Systemic Immunodeficiency in Patients With Uveitis With a Suspected Infectious Etiology

PURPOSE

To determine the correlation between the presence of torque teno virus (TTV) in the aqueous humor of patients with uveitis and clinical information, including immunodeficiency history.

DESIGN

Multicenter, retrospective, cross-sectional study.

METHODS

Fifty-eight patients with uveitis with a suspected infectious etiology and 24 controls with cataract or age-related macular degeneration were included. We used quantitative polymerase chain reaction to test all subjects for TTV and multiplex polymerase chain reaction to test uveitis subjects for common ocular pathogens. When possible, both serum and aqueous humor samples were tested. Ocular TTV positivity was compared with age, sex, and a history of systemic immunodeficiency with logistic analysis.

RESULTS

Ocular TTV positivity was found in 23%, 11%, and 0% of patients with herpetic uveitis, nonherpetic uveitis, and controls, respectively. Among patients with herpes infection, positivity for ocular TTV was found in 43%, 8%, 14%, and 50% of patients with cytomegalovirus retinitis, iridocyclitis, acute retinal necrosis, and Epstein-Barr virus-positive uveitis, respectively. Patients with cytomegalovirus retinitis showed a significantly higher rate of ocular TTV infection than controls (P = .008). Serum analysis revealed TTV positivity in 90% of patients with uveitis and in 100% of controls. Age- and gender-adjusted logistic analysis revealed a correlation between ocular TTV positivity and systemic immunodeficiency (P = .01), but no correlations between ocular TTV and age, gender, or viral pathogenic type.

CONCLUSIONS

These findings suggest that positivity for ocular TTV was correlated with a clinical history of systemic immunodeficiency.

Factors Associated with Reclosure of Posterior Capsule Aperture by Flat Opacifications with Pearls after Nd:YAG Laser Posterior Capsulotomy

In this retrospective case series, we investigated factors associated with posterior capsule aperture (PCA) reclosure following neodymium-yttrium aluminum garnet (Nd:YAG) laser posterior capsulotomy. The study encompassed patients who underwent cataract surgery with intraocular lens (IOL) implantation or a combined vitrectomy, cataract surgery, and IOL implantation between 2009 and 2022. PCA reclosure was observed in 22 eyes of 17 patients: 45% (10 eyes) underwent the triple procedure, and 55% (12 eyes) received cataract surgery with IOL implantation. In our clinic, 14% of patients were given IOLs with a 4% water content, while 73% (13 eyes) of those experiencing PCA reclosure had IOLs with a 4% water content. The mean interval between Nd:YAG capsulotomies was notably shorter than that between the initial cataract surgery and the first Nd:YAG laser capsulotomy. We also identified five stages of PCA reclosure progression. In conclusion, IOL water content may be linked to PCA reclosure, and the time to recurrence is shorter with each successive reclosure. Further research is needed to verify these findings and uncover additional contributing factors.

Findings in pseudophakic eye that developed liquefied aftercataract-like substance one day after vitrectomy

Purpose

Observations

Conclusions and importance

Role of Caveolin-1 for Blocking the Epithelial-Mesenchymal Transition in Proliferative Vitreoretinopathy

Purpose

Proliferative vitreoretinopathy (PVR) is one of the most severe ocular diseases. Fibrotic changes in retinal cells are considered to be involved in the pathogenesis of PVR. Epithelial-mesenchymal transition (EMT) of RPE cells is one of the main concepts in the pathogenesis of fibrovascular membranes (FVMs) in PVR. In this study, we examined the expression of Caveolin-1 in human FVMs from patients with PVR. We also examined the role of Caveolin-1 in the pathogenesis of PVR.

Methods

Western blotting, real-time PCR, and immunohistochemistry were performed with human FVMs and mouse eyes with PVR. Cell migration assays were performed to evaluate the involvement of Caveolin-1 in EMT using primary human and mouse RPE cells.

Results

Caveolin-1 was expressed in human FVMs and upregulated in the mouse eyes with PVR. The alpha-smooth muscle actin (αSMA) expression and migration ability were increased in RPE cells with knockout or knockdown of Caveolin-1, whereas zonula occludens-1 (ZO-1) immunohistochemistry showed reduced morphology and expression of ZO-1. In addition, migration assays showed that Caveolin-1 reduction increased RPE cell migration abilities.

Conclusions

These results indicated that Caveolin-1 in RPE cells prevents PVR by blocking EMT.

High-dose intravenous pulse steroid therapy for optic disc swelling and subretinal fluid in non-arteritic anterior ischemic optic neuropathy

Non-arteritic anterior ischemic optic neuropathy (NAION) is a disease with microvascular abnormality that causes acute optic disc swelling (ODS) and, in severe cases, subretinal fluid (SRF) accumulation. ODS causes compartment syndrome and subsequent axonal degeneration and loss of retinal ganglion cells by apoptosis. No treatment modalities have been effective, although some cases improved after the intake of oral systemic steroids. We reported a case of a 72-year-old man who was referred due to a visual defect in the right eye. At first presentation, visual acuity and visual field were disturbed; critical flicker frequency (CFF) was decreased; and optic coherence tomography (OCT) showed ODS and SRF. Microscopic examination revealed parapapillary hemorrhage and fluorescence angiography showed non-filling, temporal-superior choroidal lesion adjacent to the optic disc at an early phase. After high-dose intravenous steroid treatment, SRF and ODS were decreased, and completely resolved after 30 days. Visual acuity and CFF were improved, and visual field was enlarged. High-dose intravenous steroids could possibly resolve SRF and ODS and improve visual function of patients with NAION. Some cases in NAION improved visual acuity and visual function in natural course, more cases were needed to evaluate the efficiency.

Better Visual Outcome by Intraocular Lens Ejection in Geriatric Patients with Ruptured Ocular Injuries

Ocular trauma is one of the leading causes of visual impairment worldwide. Because of the popularity of cataract surgeries, aged individuals with ocular trauma commonly have a surgical wound in their eyes. The purpose of this study was to evaluate the visual outcome of cases that were coincident with intraocular lens (IOL) ejection in the eyes with ruptured open-globe ocular injuries. Consecutive patients with open-globe ocular injuries were first reviewed. Patients’ characteristics, corrected distance visual acuities (CDVAs) over 3 years after the trauma, causes of injuries, traumatic wound patterns, and coexistence of retinal detachment were examined. The relationships between poor CDVA and the other factors, including the complications of crystalline lens and IOL ejection, were examined. A total of 105 eyes/patients [43 eyes with rupture, 33 with penetrating, 28 with intraocular foreign body (IOFB), and 1 with perforating injuries] were included. Rupture injuries were common in aged patients and were mostly caused by falls, whereas penetrating and IOFB injuries were common in young male patients. CDVAs of the eyes with rupture injuries were significantly worse than those of the eyes with penetrating or IOFB injuries. CDVA from more than 50% of the ruptured eyes resulted in no light perception or light perception to 20/500. CDVA of the ruptured eyes complicated by crystalline lens ejection was significantly worse than that of those complicated by IOL ejection. The wounds of the ruptured eyes complicated by IOL ejection were mainly located at the superior corneoscleral limbus, whereas those of the eyes complicated by crystalline lens ejection were located at the posterior sclera. There were significant correlations between poor CDVA and retinal detachment and crystalline lens ejection. These results proposed a new trend in the ocular injuries that commonly occur in aged patients; history of cataract surgery might affect the final visual outcome after open-globe ocular injuries.

Non-Descemet Stripping Automated Endothelial Keratoplasty for Bullous Keratopathy in Buphthalmic Eye

PURPOSE

To report the 2-year follow-up findings in a patient with buphthalmic bullous keratopathy (BK) who was successfully treated with non-Descemet stripping automated endothelial keratoplasty (nDSAEK).

METHODS

A 39-year-old man had an endothelial graft of 8.0 mm diameter placed uneventfully using the nDSAEK method for phakic BK with buphthalmos of the left eye. He had had a penetrating keratoplasty in the right eye due to aphakic BK 5 years earlier, which, however, resulted in the invasion of blood vessels and graft failure. Since the left eye was phakic, Descemetorhexis was not performed because the instruments might touch the crystalline lens. The best-corrected visual acuity (BCVA), intraocular pressure (IOP), and endothelial cell density (ECD) were determined at 2 weeks, and at 1, 3, 6, 12, 18 and 24 months after nDSAEK.

RESULTS

Twenty-four months after nDSAEK, his left cornea and lens remained clear, and the decimal BCVA was 0.8. However, the ECD of the graft had decreased from 2,274 cells/mm(2) before nDSAEK to 539 cells/mm(2) 24 months after the surgery, and the rate of decrease appeared to be slightly faster than that of former reports. An IOP of $1003e;30 mm Hg was recorded at around 2 months after the surgery, but was well controlled by tapering the topical steroids and the addition of topical brinzolamide and latanoprost.

CONCLUSION

Our findings show that nDSAEK can be successfully used to treat buphthalmic BK. We recommend that nDSAEK be considered especially in phakic eyes with a smooth posterior surface around the pupillary area.

Novel OPN1LW/OPN1MW deletion mutations in 2 Japanese families with blue cone monochromacy

Blue cone monochromacy (BCM) is caused by the lack of expression of the normal proteins encoded by the OPN1LW and OPN1MW genes, resulting in the absence of red and green cone sensitivities. We analyzed two cases of BCM in two different families and identified deletion mutations in the locus control region upstream of the two genes. Deletion breakpoints were determined to an accuracy of one base for both cases.

Histamine H4 receptor as a new therapeutic target for choroidal neovascularization in age-related macular degeneration

BACKGROUND AND PURPOSE

The present treatment for choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD) is not sufficient. Hence, we examined the therapeutic efficacy of reducing histamine H4 receptor expression on CNV in mice.

EXPERIMENTAL APPROACH

H4 receptor expression was examined in CNVs from patients with AMD. In mice, laser photocoagulation was performed in the retina to induce experimental CNV (laser CNV). Protein and mRNA expression levels were determined and CNV volume measured in wild-type and Hrh4(-/-) mice with laser CNV. The effects of JNJ7777120, an H4 receptor antagonist, administered intravitreously, on CNV volume and pathological vessel leakage were determined in mice with laser CNV and controls. Fundus imaging, retinal histology and electroretinography were performed on eyes injected with JNJ7777120 to evaluate retinal toxicity.

KEY RESULTS

Human H4 receptors were only confirmed in CNV samples from AMD patients and not in the other subretinal tissues. Mouse H4 receptors were expressed in retinal pigment epithelium only after inducing laser CNV in wild-type mice, and were co-localized with the macrophage marker F4/80. Laser CNV volume was reduced in Hrh4(-/-) mice compared with that in wild-type mice, and JNJ7777120 suppressed laser-induced CNV volume and pathological CNV leakage in wild-type mice. Also eyes injected with JNJ7777120 did not show retinal degeneration.

CONCLUSIONS AND IMPLICATIONS

H4 receptors are expressed in macrophages that accumulate around CNVs. Suppressing H4 receptor expression prevented the pathological vessel leakage without showing retinal toxicity, indicating that the H4 receptor has potential as a novel therapeutic target in AMD.

Expression of Vascular Endothelial Growth Factor by Retinal Pigment Epithelial Cells Induced by Amyloid-β Is Depressed by an Endoplasmic Reticulum Stress Inhibitor

PURPOSE

Amyloid-β (Aβ) is a 36- to 43-amino-acid peptide that is a constituent of drusen, and it has been demonstrated to upregulate vascular endothelial growth factor (VEGF) expression by retinal pigment epithelial (RPE) cells. This study aimed to determine whether 4-phenylbutyl phosphonylacetate (PBA), a known endoplasmic reticulum (ER) stress inhibitor, can reduce Aβ-induced expression of VEGF in RPE cells.

METHODS

Aβ was added to the medium of regularly cultured or polarized ARPE-19 cells, a human RPE cell line, with or without PBA. The levels of VEGF and ER stress markers, namely GRP78/Bip, cleaved caspases 4 and 12 and GADD153/C-EBP homologous protein, were determined by enzyme-linked immunoassay, immunocytochemistry and Western blotting.

RESULTS

Exposure of ARPE-19 cells to Aβ induced GRP78/Bip expression and activated caspases 4 and 12; however, their expression was decreased by simultaneous exposure to PBA. Aβ increased the expression of VEGF both in regularly cultured and polarized ARPE-19 cells, but it was suppressed by PBA. PBA did not cause RPE cell apoptosis.

CONCLUSION

Aβ has been suggested to be involved in the development of age-related macular degeneration; therefore, our findings suggest that drugs that target ER stress should be considered for the treatment of age-related macular degeneration.

Flicker electroretinograms before and after intravitreal ranibizumab injection in eyes with central retinal vein occlusion

PURPOSE

To compare the amplitudes and implicit times of the flicker electroretinograms before and after an intravitreal injection of ranibizumab (IVR) in eyes with a central retinal vein occlusion (CRVO).

METHODS

We reviewed the medical records of 15 consecutive patients who had macular oedema secondary to CRVO and had received an IVR at the Nagoya University Hospital from November 2013 to July 2014. Flicker ERGs were recorded with both the RETeval(™) system and a conventional ERG system before the IVR. One month after the IVR, recordings were repeated with only the RETeval(™) system.

RESULTS

The mean implicit times of the flicker ERGs of the affected eyes recorded with the RETeval(™) system were significantly longer than that of the fellow eyes (32.2 ± 2.6 msec versus 28.1 ± 1.2 msec, p < 0.001). One month after the IVR, the implicit times of the flicker ERGs of affected eyes were significantly shortened from 32.2 ± 2.6 to 30.6 ± 2.2 msec (p < 0.001).

CONCLUSIONS

The shortening of the implicit times of the flicker ERGs after the IVR indicates an improvement of retinal function after anti-VEGF therapy for CRVO eyes.

Buckling surgery and supplemental intravitreal bevacizumab or photocoagulation on stage 4 retinopathy of prematurity eyes

PURPOSE

To report the results of scleral buckling (SB) with or without photocoagulation (PC) and intravitreal bevacizumab (IVB) for stage 4 retinopathy of prematurity (ROP) eyes.

METHODS

Forty-two eyes of 28 patients with SB and/or PC or IVB were studied. Twenty-nine eyes had stage 4A and 13 eyes had stage 4B ROP. Seventeen eyes underwent SB combined with additional intraoperative or postoperative treatments (combined group). Twenty-five eyes underwent SB without additional therapy (non-combined group). The concentrations of vascular endothelial growth factor (VEGF) in the aqueous humor determined by enzyme-linked immunosorbent assay were compared between the two groups. The initial and final reattachment rates were also compared.

RESULTS

The gestational age and birth weight were 25.0 ± 2.0 weeks and 786 ± 222 g in the combined group, and 25.5 ± 2.1 weeks and 899 ± 315 g in the non-combined group. The postmenstrual age at the time of initial surgery was 38.0 ± 1.9 in the combined and 44.1 ± 4.0 weeks in the non-combined group (P < 0.001). The initial reattachment rate was 92% in stage 4A and 75% in stage 4B of ROP eyes in the combined group, and the rate was 93% in stage 4A and 33% in stage 4B of ROP eyes in the non-combined group. The mean VEGF concentration in aqueous humor was 1923 ± 779 pg/ml in the combined group and 985 ± 303 pg/ml in the non-combined group (P < 0.05).

CONCLUSION

Our results show that the retinal reattachment rate after combined therapy was comparable to that in the non-combined group. We conclude that combined therapy may be effective even in ROP eyes with high activity.

Significant Correlation between Retinal Venous Tortuosity and Aqueous Vascular Endothelial Growth Factor Concentration in Eyes with Central Retinal Vein Occlusion

PURPOSE

To determine whether the degree of venous tortuosity is significantly correlated with the aqueous vascular endothelial growth factor (VEGF) concentration in eyes with a central retinal vein occlusion (CRVO).

METHODS

We reviewed the medical records of 32 eyes of 32 patients who had macular edema due to a CRVO. All of the patients were examined at the Nagoya University Hospital and were scheduled to receive an intravitreal injection of bevacizumab (IVB) or ranibizumab (IVR) within 12 weeks of the onset of the CRVO to treat the macular edema. Aqueous humor was collected just before the IVB or IVR, and the VEGF concentration was determined by enzyme-linked immunosorbent assay (ELISA). The venous tortuosity index was calculated by dividing the length of the retinal veins by the chord length of the same segment. The correlation between the mean tortuosity index of the inferotemporal and supratemporal branches of the retinal vein and the aqueous VEGF concentration was determined.

RESULTS

The mean aqueous VEGF concentration was 384 ± 312 pg/ml with a range of 90 to 1077 pg/ml. The degree of venous tortuosity was significantly correlated with the VEGF concentration in the aqueous. (r = 0.49, P = 0.004), with the foveal thickness (r = 0.40, P = 0.02), and with the best-corrected visual acuity (r = 0.38, P = 0.03).

CONCLUSIONS

The significant correlation between the aqueous VEGF concentration and the venous tortuosity indicates that the degree of retinal venous tortuosity can be used to identify eyes that are at a high risk of developing neovascularization.

Suppression of Laser-Induced Choroidal Neovascularization by the Oral Medicine Targeting Histamine Receptor H4 in Mice

PURPOSE

This study aimed to examine relationship of histamine receptor H4 (HRH4) and the pathogenesis of laser-induced choroidal neovascularization (laser-CNV) and to determine whether oral administration of HRH4 antagonists suppressed laser-CNV in mice.

METHODS

Laser photocoagulation was performed in mice to induce the laser-CNV. Histamine was administered intravitreously, and CNV volume was measured. Laser photocoagulation and intravitreous injection of HRH4 antagonist JNJ7777120 were performed after intraperitoneal injection of clodronate liposome, which depletes circulating monocyte-derived macrophages; CNV volume was compared with that in mice injected with control (dimethyl sulfoxide [DMSO]/PBS). Three days after laser-CNV, the F4/80⁺CD11b⁺ macrophage population in retinal pigment epithelium (RPE)/choroid complex was quantified with flow cytometry in wild-type and Hrh4^-/- mice. The long-acting HRH4 antagonist JNJ28307474 was then administrated periorally, and the laser-CNV volume was compared with controls.

RESULTS

Intravitreous injection of histamine did not affect laser-CNV volume. The laser-CNV from the eye injected with JNJ7777120 was equivalent to that injected with the DMSO/PBS in mice that had intraperitoneally received clodronate liposome. Flow cytometry after laser-CNV induction revealed a smaller F4/80⁺CD11b⁺ macrophage population in the RPE/choroid complex of Hrh4^-/- mice than in wild-type mice. Oral administration of JNJ28307474 significantly reduced laser-CNV volume in wild-type mice.

CONCLUSIONS

Our results suggested that HRH4-positive macrophages played an important role in the pathogenesis of laser-CNV and that they require a different ligand from that of histamine. The oral administration of an HRH4 antagonist successfully reduced laser-CNV.

TRANSLATIONAL RELEVANCE

Our results indicate that drugs targeting HRH4 are potentially a novel oral treatment for age-related macular degeneration.

Interleukin-18 induces retinal pigment epithelium degeneration in mice

PURPOSE

To examine the effectiveness of interleukin-18 (IL-18) on choroidal neovascularization (CNV) and retinal pigment epithelium (RPE) in humans and mice.

METHODS

Serum IL-18 levels in patients with wet and dry AMD who were older than 50 years were measured and compared with those of age-matched controls. In mice, laser photocoagulation was performed in the retina to induce experimental CNV, and CNV volume was measured in eyes injected with recombinant IL-18 (rIL-18) and IL-18 neutralizing antibody (nIL-18Ab) compared with those injected with control. Tube formation assay was performed on human retinal endothelial cells (HREC) with rIL-18 administration in vitro. After subretinal injection of rIL-18, fundus change in the injected eyes was evaluated; active caspase-3 level was measured in the RPE/choroid complex, and tight junction integrity in RPE was visualized by zonula occludens-1 (ZO-1) staining.

RESULTS

Serum IL-18 levels in dry AMD patients were higher than those in control. Mouse rIL-18 or nIL-18Ab did not induce significant change in CNV volume compared with controls or change tube formation in HREC. Subretinal injection of rIL-18 induced retinal degeneration in the mice fundus; ZO-1 staining showed considerably disturbed RPE structure, and active caspase-3 expression was significantly higher after rIL-18 induction.

CONCLUSIONS

Interleukin-18 did not show a pro- or antiangiogenic effect on mouse laser-induced CNVs (laser-CNVs), whereas it directly induced RPE cell apoptosis in the mouse eye. Our results suggested that IL-18 is associated with dry AMD, but not with wet AMD.

Electroretinograms and level of aqueous vascular endothelial growth factor in eyes with hemicentral retinal vein occlusion or branch retinal vein occlusion

PURPOSE

Hemicentral retinal vein occlusion (hCRVO) is a disease related to CRVO but not to branch retinal vein occlusion (BRVO). We reported a significant correlation between aqueous vascular endothelial growth factor (VEGF) levels and the implicit time of 30-Hz flicker electroretinogram (ERG) in CRVO eyes. The purpose of this study was to compare aqueous VEGF levels and ERG components between hCRVO and BRVO eyes.

METHODS

The medical records of patients with macular edema secondary to hCRVO (12 eyes) or BRVO (16 eyes) and received an intravitreal injection of bevacizumab (IVB) at the Nagoya University Hospital from July 2009 to May 2013 were reviewed. Full-field ERGs were recorded before the IVB. Aqueous humor was collected just before the IVB to measure VEGF concentration. Differences in aqueous VEGF level and ERG components between hCRVO and BRVO eyes were determined.

RESULTS

Mean aqueous VEGF concentration in hCRVO eyes was significantly higher than that in BRVO eyes (504 vs. 148 pg/ml, P < 0.05). The implicit time of 30-Hz flicker ERG was significantly longer in hCRVO than in BRVO eyes (33.5 vs. 29.8 ms, P < 0.01).

CONCLUSION

The significant difference in VEGF levels in aqueous and implicit times of 30-Hz flicker ERG suggest that retinal ischemia is more manifest in hCRVO than in BRVO eyes.

Age-dependent alteration of intraocular soluble heparan sulfate levels and its implications for proliferative diabetic retinopathy

PURPOSE

To assess the relationship between intraocular soluble heparan sulfate (HS) concentration and age in subjects with and without diabetic retinopathy.

METHODS

Vitreous from subjects with idiopathic maculopathies (n=17), i.e., macula hole or epiretinal membrane, or nonproliferative diabetic retinopathy (non-PDR; n=5) and aqueous humor from subjects with PDR (n=16), non-PDR (n=7), or cataracts (n=15) was collected. The levels of HS and vascular endothelial growth factor (VEGF) were measured using enzyme-linked immunosorbent assay. Concentrations of sulfated glycosaminoglycan were determined through dimethylmethylene blue-based assay. The effect of the vitreal HS level on the binding of exogenous VEGF to surface-bound heparin was determined in vitro.

RESULTS

The level of HS in vitreous samples from subjects with idiopathic maculopathies increased concomitantly with age (p=0.020, R²=0.327). Meanwhile, HS levels in aqueous humor were lower in PDR subjects than in non-PDR (p=0.003) and cataract subjects (p=0.007). However, the PDR subjects were significantly younger than the non-PDR subjects (p<0.001) or cataract subjects (p<0.001). When the three groups were controlled for age, the levels of HS glycosaminoglycans were no longer different between the three (p=0.247). The increasing level of HS or sulfated glycosaminoglycan in the vitreous was associated with its increased inhibitory effect on interaction between VEGF and surface heparin in vitro (p=0.014, R²=0.377).

CONCLUSIONS

The HS level of the intraocular fluid increased with age. The possible link between low HS in intraocular fluid and increased localization of VEGF at the retinal surface may provide one explanation for the higher susceptibility of younger subjects with diabetes mellitus to developing PDR.

Influence of preoperative intravitreal bevacizumab on visual function in eyes with proliferative diabetic retinopathy

PURPOSE

Although bevacizumab, a humanized monoclonal antibody against vascular endothelial growth factor (VEGF), is effective in treating ocular neovascularization, there are some concerns about whether blocking VEGF might be harmful to retinal neurons. The purpose of this study was to evaluate the effects of preoperative intravitreal bevacizumab (IVB) on the visual function of eyes with proliferative diabetic retinopathy (PDR).

METHODS

Thirty eyes of 23 patients (13 men and 10 women) with PDR who were treated at the Nagoya University Hospital from November 2006 to October 2009 were studied. All of the eyes were treated with 1.25 mg/0.05 ml of IVB 2-8 days before the vitrectomy. The protocol was approved by the Institutional Review Board of Nagoya University, and a written informed consent was obtained from each patient. All of the eyes had an active proliferative membrane with vitreous hemorrhage, but the fundus was visible. The mean age of the patients was 41.6 ± 10 years (range, 27-59), and the mean follow-up period was 9.7 ± 8.9 months (range, 1-24) after the vitrectomy. The visual acuity (VA) was measured, the visual fields were determined by Goldmann perimetery, and full-field electroretinograms (ERGs) were recorded before IVB, and before and after the vitrectomy. Fluorescein angiography was also performed before and after IVB. The area of the visual field was measured using a computer software (Scion Image).

RESULTS

All eyes showed a regression of the new vessels and a reduction of fluorescent leakage from the new vessels after IVB. In addition, there was less bleeding during the removal of the proliferative membrane. The average VA was improved postoperatively from 20/250 to 20/70. However, there was no significant change in the amplitudes of the a- (from 261.4 to 259.2 µV) and b-waves (from 256.9 to 253.3 µV) of the ERGs, and there was no significant change in the visual field area after the surgery (from 8,322.5 to 7,496.3 degrees(2)). No significant ocular or systemic adverse events were observed.

CONCLUSION

IVB-assisted vitrectomy led to an improvement of the VA in eyes with PDR without significant adverse events. There was no change in the visual fields and ERGs. Although only a small number of patients were studied, we conclude that IVB is most likely not harmful to retinal neurons if bevacizumab is washed out in less than 1 week. In addition, preoperative IVB made the surgery much easier by decreasing the activity of new vessels.

Visual function 5 years or more after macular translocation surgery for myopic choroidal neovascularisation and age-related macular degeneration

PURPOSE

To evaluate the changes in the best-corrected visual acuity (BCVA) after 1 year and after ≥ 5 years after macular translocation for age-related macular degeneration (AMD) or myopic choroidal neovascularisation (mCNV).

METHODS

The medical records of 61 consecutive patients who underwent macular translocation with 360° retinotomy for AMD (35 eyes) or mCNV (26 eyes) were reviewed. Overall, 40 patients, 17 mCNV and 23 AMD, were followed for at least 5 years. BCVA and area of the Goldmann visual field (VF) measured before, 12 months after surgery, and at the final visit.

RESULTS

In the 23 AMD eyes followed for ≥ 5 years, the mean preoperative BCVA was 1.149 ± 0.105 logMAR units, which significantly improved to 0.69 ± 0.06 logMAR units at 1 year (P<0.001). This BCVA was maintained at 0.633 ± 0.083 logMAR units on their final examination. In the 17 eyes with mCNV followed for ≥ 5 years, the mean preoperative BCVA was 1.083 ± 0.119 logMAR units, which was significantly improved to 0.689 ± 0.121 logMAR units at 1 year (P = 0.001). This BCVA was maintained at 0.678 ± 0.142 logMAR units on their final examination. The area of the VF was significantly decreased at 12 months and did not change significantly thereafter.

CONCLUSIONS

Our results show that macular translocation surgery significantly improves the BCVA and significantly decreases the VF area of eyes with mCNV or AMD after first 1 year. The BCVA and VF area do not change significantly from the values at 1 year for at least 5 years.

Significant correlation between electroretinogram parameters and ocular vascular endothelial growth factor concentration in central retinal vein occlusion eyes

PURPOSE

Central retinal vein occlusion (CRVO) leads to retinal ischemia, which then induces an upregulation of vascular endothelial growth factor (VEGF). The aim of this study was to determine whether a significant correlation exists between the ocular VEGF levels and the amplitudes and implicit times of different components of the electroretinogram (ERG) in eyes with a CRVO.

METHODS

The medical records of the 20 consecutive patients who had macular edema secondary to CRVO and were examined at the Nagoya University Hospital from November 2008 to February 2010 were reviewed. Because all the patients were scheduled to receive an intravitreal injection of bevacizumab (IVB), it was possible to collect samples of the aqueous humor before the IVB. The correlation between the different components of the ERGs and the VEGF concentration in the aqueous was determined.

RESULTS

The mean VEGF concentration of the aqueous humor was 416 pg/mL with a range of 100-1260 pg/mL. The b/a ratio of the single flash ERGs (P = 0.049; ρ = -0.45), implicit times of the cone a-wave (P = 0.028; ρ = 0.50), cone b-wave (P = 0.0059; ρ = 0.63), and 30 Hz flicker ERGs (P = 0.0058; ρ = 0.63) were significantly correlated with the VEGF concentration in the aqueous.

CONCLUSIONS

The significant correlations between the different components of the ERGs and the aqueous VEGF concentration indicate that full-field ERGs can be used to detect the CRVO patients at a high risk of developing neovascularization of the iris.

Regulation of pathologic retinal angiogenesis in mice and inhibition of VEGF-VEGFR2 binding by soluble heparan sulfate

Development of the retinal vascular network is strictly confined within the neuronal retina, allowing the intraocular media to be optically transparent. However, in retinal ischemia, pro-angiogenic factors (including vascular endothelial growth factor-A, VEGF-A) induce aberrant guidance of retinal vessels into the vitreous. Here, we show that the soluble heparan sulfate level in murine intraocular fluid is high particularly during ocular development. When the eyes of young mice with retinal ischemia were treated with heparan sulfate-degrading enzyme, the subsequent aberrant angiogenesis was greatly enhanced compared to PBS-injected contralateral eyes; however, increased angiogenesis was completely antagonized by simultaneous injection of heparin. Intraocular injection of heparan sulfate or heparin alone in these eyes resulted in reduced neovascularization. In cell cultures, the porcine ocular fluid suppressed the dose-dependent proliferation of human umbilical vein endothelial cells (HUVECs) mediated by VEGF-A. Ocular fluid and heparin also inhibited the migration and tube formation by these cells. The binding of VEGF-A and HUVECs was reduced under a high concentration of heparin or ocular fluid compared to lower concentrations of heparin. In vitro assays demonstrated that the ocular fluid or soluble heparan sulfate or heparin inhibited the binding of VEGF-A and immobilized heparin or VEGF receptor 2 but not VEGF receptor 1. The recognition that the high concentration of soluble heparan sulfate in the ocular fluid allows it to serve as an endogenous inhibitor of aberrant retinal vascular growth provides a platform for modulating heparan sulfate/heparin levels to regulate angiogenesis.

Regression of macular edema secondary to branch retinal vein occlusion during anti-TNF-alpha therapy for rheumatoid arthritis

A patient with macular edema secondary to a branch retinal vein occlusion (BRVO) was treated with intravenous injections of infliximab, an antitumor necrosis factor (TNF)-α antibody, for her rheumatoid arthritis (RA). Before the injection, the thickness of the right fovea, determined by optical coherent tomography, was 629 μm and the best-corrected visual acuity (BCVA) was 20/50. After eight injections of infliximab and 10 months after the first injection, her foveal thickness was decreased to 293 μm and the visual acuity improved to 20/20. There was no recurrence of macular edema during the infliximab injections. However, the infliximab injection was stopped because the patient developed pneumonia. Eight months after stopping the infliximab injection, her foveal thickness increased to 494 μm. To treat the RA, her orthopedists began weekly subcutaneous injections of etanercept, a fusion protein of a section of the TNF receptor and immunoglobulin. Five months later, the foveal thickness had decreased to 260 μm, and the visual acuity remained at 20/25⁺. Because TNF-α is known to break down the blood–retinal barrier, the improvements in our case suggest that TNF-α plays a role in the pathogenesis of macular edema in some patients with BRVO.

Equine infectious anemia viral vector-mediated codelivery of endostatin and angiostatin driven by retinal pigmented epithelium-specific VMD2 promoter inhibits choroidal neovascularization

Equine infectious anemia virus (EIAV) is a nonprimate lentivirus that does not cause human disease. Subretinal injection into mice of a recombinant EIAV lentiviral vector in which lacZ is driven by a CMV promoter (EIAV CMV LacZ) resulted in rapid and strong expression of LacZ in retinal pigmented epithelial (RPE) cells and some other cells including ganglion cells, resulting in the presence of 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside within the optic nerve. Substitution of the RPE-specific promoter from the vitelliform macular dystrophy (VMD2) gene for the CMV promoter resulted in prolonged (at least 1 year) expression of LacZ that was restricted to RPE cells, albeit reduced 6- to 10-fold compared with the CMV promoter. Similarly, the amount of FLAG-tagged endostatin detected in eyes injected with the EIAV VMD2 Endo(FLAG) vector was similar to that seen in eyes injected with a vector that expressed both endostatin and angiostatin [EIAV VMD2 Endo(FLAG)/Angio]; expression was approximately 6-fold lower than with identical vectors in which the CMV promoter drove expression. Compared with murine eyes treated with a control EIAV vector, subretinal injection of EIAV vectors expressing murine endostatin alone or in combination with angiostatin driven by either the CMV or VMD2 promoter caused significant suppression of choroidal neovascularization (NV) at laser-induced rupture sites in Bruch's membrane. These data support proceeding toward clinical studies with EIAV-based gene therapy for choroidal NV, using the VMD2 promoter to selectively drive expression of a combination of endostatin and angiostatin in RPE cells.

Paraneoplastic retinopathy associated with retroperitoneal liposarcoma

We report a case of paraneoplastic retinopathy associated with a retroperitoneal liposarcoma. A 42-year-old man was referred to our hospital with complaints of night blindness and blurred vision in the peripheral field. Electroretinograms showed a progressive amplitude reduction in his both eyes. Abdominal magnetic resonance imaging showed a large retroperitoneal mass, and pathologic examination revealed a dedifferentiated liposarcoma. Western blot analysis showed an antiretinal antibody in the serum of our patient, and his serum reacted with the photoreceptors of a bovine retina. To the best of our knowledge, this is the first case of paraneoplastic retinopathy associated with a liposarcoma.

Transfer of gene to human retinal pigment epithelial cells using magnetite cationic liposomes

AIM

To present a new method called magnetolipofection which can transfect cells in a specific area of the retinal pigment epithelium (RPE) by magnetic force as a non-viral gene transfection.

METHODS

ARPE-19 (a human RPE cell line) cells were cultured with a mixture of cationic lipid, plasmid DNAs and magnetite nanoparticles. A sheet of ARPE-19 cells was transfected in the vertical direction by placing a magnet under the centre of the culture plate. Horizontal gene transfection was also performed.

RESULTS

When magnetolipofection was performed in the vertical direction, there was a significantly larger number of green fluorescent protein (GFP)-positive cells where the magnet was placed than in the peripheral area, and the number was equivalent to the number transfected with Lipofectamine2000. In the horizontal direction, there was also a significantly larger number of GFP-positive cells, but there was almost no gene transfer detected using Lipofectamine2000.

CONCLUSION

The area of gene transfection can be controlled by the placement of a magnet in the area selected to be transfected in vitro by magnetolipofection. This method can be used to transfect RPE cells in selected areas which should be helpful for experimental and clinical applications.

[New therapies for age-related macular degeneration]

Age-related macular degeneration (AMD) is a major cause of blindness in the elderly in developed countries. New treatments have been developed, and they can be grouped into those that selectively disrupt new vessels, e.g., photodynamic therapy; and those that target molecules that play an important role in angiogenesis, e.g., anti-vascular endothelial growth factor (VEGF) drugs. Ranibizumab, the anti-VEGF-drug, was the first drug that led to an improvement of visual acuity. However, a disadvantage of this drug is the need of repeated injection, and to overcome this disadvantage, gene therapy and some other methods are being studied. A clinical trial of gene therapy is being performed in the U.S.A. In this review, we describe the new therapies for AMD.

Generation of immature retinal neurons from proliferating cells in the pars plana after retinal histogenesis in mice with retinal degeneration

PURPOSE

To study the differentiation of immature retinal neurons/retinal precursors in the ciliary epithelium after retinal histogenesis in mice with inherited or acquired retinal degeneration.

METHODS

Immunoreactivity to anti-recoverin, rhodopsin, and Pax6 antibodies and binding to peanut agglutinin were analyzed histologically. The distribution and differentiation of immature retinal neurons/retinal precursors in the ciliary epithelium of mice with inherited (C3H/HeJ) and acquired (C57BL mice injected with 60 mg/kg N-methyl-N-nitrosourea) retinal degeneration were assessed. Proliferating retinal progenitors were labeled with bromodeoxyuridine (BrdU), and they were studied histologically using retinal markers.

RESULTS

Many cells of rod and cone photoreceptor lineage were identified within the ciliary epithelium of the pars plana in adult mice with inherited retinal degeneration. Tracking experiments using BrdU indicated that some of recoverin-positive cells in the pars plana (approximately 3%) were generated after retinal histogenesis, and few were produced at or after postnatal day 24 (P24). The induction of acquired retinal degeneration in adult wild-type mice (P30) increased the number of BrdU-positve cells by roughly fourfold and recoverin-positive cells by approximately 17-fold in the pars plana. Moreover, some (approximately 1.5%) of the recoverin-positive cells were newly generated from dividing retinal progenitors in the adult pars plana.

CONCLUSIONS

In response to retinal damage, an increased number of immature retinal neurons/retinal precursors was observed in the pars plana of mice with acquired and inherited retinal degeneration. Some of these cells differentiated from proliferating cells even after retinal histogenesis.

BEST1 expression in the retinal pigment epithelium is modulated by OTX family members

A number of genes preferentially expressed in the retinal pigment epithelium (RPE) are associated with retinal degenerative disease. One of these, BEST1, encodes bestrophin-1, a protein that when mutated causes Best macular dystrophy. As a model for RPE gene regulation, we have been studying the mechanisms that control BEST1 expression, and recently demonstrated that members of the MITF-TFE family modulate BEST1 transcription. The human BEST1 upstream region from -154 to +38 bp is sufficient to direct expression in the RPE, and positive-regulatory elements exist between -154 and -104 bp. Here, we show that the -154 to -104 bp region is necessary for RPE expression in transgenic mice and contains a predicted OTX-binding site (Site 1). Since another non-canonical OTX site (Site 2) is located nearby, we tested the function of these sites using BEST1 promoter/luciferase constructs by in vivo electroporation and found that mutation of both sites reduces promoter activity. Three OTX family proteins - OTX1, OTX2 and CRX - bound to both Sites 1 and 2 in vitro, and all of them increased BEST1 promoter activity. Surprisingly, we found that human and bovine RPE expressed not only OTX2 but also CRX, the CRX genomic region in bovine RPE was hypersensitive to DNase I, consistent with active transcription, and that both OTX2 and CRX bound to the BEST1 proximal promoter in vivo. These results demonstrate for the first time CRX expression in the RPE, and suggest that OTX2 and CRX may act as positive modulators of the BEST1 promoter in the RPE.

Topical administration of a multi-targeted kinase inhibitor suppresses choroidal neovascularization and retinal edema

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.

Characteristics of bone marrow-derived microglia in the normal and injured retina

PURPOSE

To compare the distribution and immunologic characteristics of bone marrow (BM)-derived and resident microglia in the retina.

METHODS

Mice were irradiated and injected with enhanced green fluorescent protein-positive (EGFP(+)) BM cells. One month to 12 months after BM transplantation, eyes were analyzed histologically for the expression of EGFP and various monocyte/microglia/macrophage markers (Iba-1, F4/80, GS-1, major histocompatibility complex [MHC] class II). N-methyl-N-nitrosourea (MNU) was injected or retinal detachment was created to induce retinal damage.

RESULTS

Many BM-derived EGFP(+) cells were found in the ciliary body and choroid and around the optic nerve in the uninjured eyes. Within the retina, few such cells existed at the retinal margin and juxtapapillary area at 3 to 12 months after BM transplantation. However, after MNU injection, many EGFP(+) cells were found in the retina adjacent to the retinal vessels, optic nerve, and ciliary body that rapidly spread throughout the retina. Most of them showed morphologic and immunohistochemical features of microglia. By 7 days after MNU injection, EGFP(+) BM-derived cells occupied approximately 15% of the total Iba-1(+) retinal microglia. Meanwhile, the proportion of MHC class II(+) cells was larger among BM-derived (EGFP(+)/Iba-1(+)) than resident (EGFP(-)/Iba-1(+)) microglia. In the eyes with retinal detachment, EGFP(+)/F4/80(+) cells engrafted exclusively around the detached retina.

CONCLUSIONS

In response to retinal damage, numerous BM-derived cells migrated to the retina from the ciliary body, optic nerve, and retinal vessels and differentiated into microglia. The higher rate of immunologic activation and the increased specificity to the damaged site appeared to be the characteristic features of BM-derived microglia.

Retardation of photoreceptor degeneration in the detached retina of rd1 mouse

PURPOSE

To study the neuroprotective effect of experimental retinal detachment (RD) on photoreceptor degeneration in rd1 mice.

METHODS

RD was produced in the eyes of rd1 mice at postnatal day (P) 9. These eyes were collected and compared to controls without RD. The effects of RD on retinal degeneration were evaluated by histochemical staining of nuclei in the outer nuclear layer (ONL), rod and cone photoreceptors, and retinal vessels at P30 in retinal sections and flatmounts. Apoptotic photoreceptors were detected by TdT-mediated dUTP nick-end labeling (TUNEL) at P15. Mice with or without RD were also reared in darkness and evaluated immunohistochemically at P30.

RESULTS

The numbers of rhodopsin-positive (rod), peanut agglutinin-positive (cone), and diamino-2-phenyl-indol-stained (rod-plus-cone) cells in the ONL were increased by 2.0-fold, 1.3-fold, and 1.2-fold, respectively, in the rd1 eyes with RD compared to those without RD at P30. In the detached retina, the cone photoreceptor inner/outer segment structures and the deep retinal vessels surrounding the inner nuclear layer and the ONL, but not the ganglion cell layer, were preserved. At P15, TUNEL-positive cell numbers in the ONL were significantly reduced in the eyes with RD. Light exposure had no effect on photoreceptor degeneration in the eyes with or without RD.

CONCLUSIONS

RD mediates the preservation of cone and rod photoreceptors in the ONL and surrounding vascular structures by reducing the rate of apoptosis of photoreceptors in rd1 mice. Light deprivation does not appear to be one of the mechanisms of photoreceptor protection in the detached retinas in these mice.

The role of VEGF and VEGFR2/Flk1 in proliferation of retinal progenitor cells in murine retinal degeneration

PURPOSE

To analyze the role of VEGF and its receptors, VEGFR2/Flk1 and VEGFR1/Flt1, on retinal progenitor cells (RPCs) in a murine model of inherited retinal degeneration (rd1 mice).

METHODS

After proliferating RPCs in the retina of rd1 mice were labeled with bromodeoxyuridine (BrdU), expressions of VEGFR2/Flk1 and VEGFR1/Flt1 were immunohistochemically analyzed. To examine its effect on the proliferation of BrdU-positive RPCs in rd1 mice, VEGF was administered into retinal culture medium with or without blocking agents against VEGFR2/Flk1 or VEGFR1/Flt1 in vitro or injected into vitreous cavity in vivo.

RESULTS

BrdU-labeled RPCs in rd1 mice expressed VEGFR2/Flk1 but not VEGFR1/Flt1. These cells later expressed retinal neuronal markers such as Pax6 and rhodopsin. Exposure of the retinas from postnatal day (P) 9 rd1 mice to VEGF increased the number of proliferating RPCs by 61% in vitro. This effect was blocked by concomitant administration of VEGFR2/Flk1 kinase inhibitor. In vivo, a single intravitreal injection of VEGF in rd1 mice at P9 increased by 138% the number of RPCs and cells that developed from RPCs in the peripheral retina at P18.

CONCLUSIONS

VEGF stimulates the proliferation of RPCs through VEGFR2/Flk1 in rd1 mice. The observed proliferation of RPCs that have the potential to differentiate into retinal neurons may enhance the regeneration of the degenerating retina.

Ocular gene transfer with self-complementary AAV vectors

PURPOSE

Self-complementary AAV (scAAV) vectors have been developed to circumvent rate-limiting second-strand synthesis in single-stranded AAV vector genomes and to facilitate robust transgene expression at a minimal dose. In this study, the authors investigated the effects of intraocular injections of type 2 scAAV.GFP in mice.

METHODS

Dose-response experiments were performed to compare conventional single-strand AAV type 2 (ssAAV2) vectors with scAAV2 vectors encoding an identical expression cassette.

RESULTS

Subretinal injection of 5 x 10(8) viral particles (vp) of scAAV.CMV-GFP resulted in green fluorescent protein (GFP) expression in almost all retinal pigment epithelial (RPE) cells within the area of the small detachment caused by the injection by 3 days and strong, diffuse expression by 7 days. Expression was strong in all retinal cell layers by days 14 and 28. In contrast, 3 days after subretinal injection of 5 x 10(8) vp of ssAAV.CMV-GFP, GFP expression was detectable in few RPE cells. Moreover, the ssAAV vector required 14 days for the attainment of expression levels comparable to those observed using scAAV at day 3. Expression in photoreceptors was not detectable until day 28. Dose-response experiments confirmed that onset of GFP expression was more rapid and robust after subretinal injection of scAAV.CMV-GFP than of ssAAV.CMV-GFP, resulting in pronounced expression in photoreceptors and other retinal neurons. Similar results were obtained for intravitreous injections.

CONCLUSIONS

These data suggest that scAAV vectors may be advantageous for ocular gene therapy, particularly in retinal diseases that require rapid and robust transgene expression in photoreceptor cells.

Gene transfer of an engineered zinc finger protein enhances the anti-angiogenic defense system

Zinc finger protein transcription factors (ZFP TFs) have been shown to positively or negatively regulate the expression of endogenous genes involved in a number of different disease processes. In this study we investigated whether gene transfer of an engineered ZFP TF designed to up-regulate expression of the chromosomal pigment epithelium-derived factor (Pedf) gene could suppress experimentally induced choroidal neovascularization (CNV). Transient transfection with engineered ZFP TFs significantly increased both Pedf messenger RNA (mRNA) and secreted PEDF protein levels in cell culture. Six weeks after intravitreous or subretinal injection of an adeno-associated viral (AAV) vector expressing the PEDF-activating ZFP TF in mice, we observed increased retinal Pedf mRNA, and a significant reduction in the size of CNV at Bruch's membrane rupture sites, assessed in vivo by fluorescein angiography or by postmortem measurements on choroidal flat mounts. Importantly, the anti-angiogenic activity persisted at 3 months after intravitreous injection. These data suggest that ZFP TF-driven enhancement of the endogenous anti-angiogenic defense system may provide a new approach for prophylaxis and treatment of neovascular diseases of the eye.

Preservation of Macular Oscillatory Potentials in Eyes of Patients with Retinitis Pigmentosa and Normal Visual Acuity

PURPOSE

To study the functional changes in the macula of the retina in the early stage of retinitis pigmentosa (RP), by analyzing each component of the focal macular electroretinogram (fmERG).

METHODS

fmERGs were recorded from 39 patients with RP with normal visual acuity (>1.0) under direct fundus observation using a modified infrared fundus camera and 5 degrees , 10 degrees , and 15 degrees stimulus spots. The amplitudes and implicit times of the a-wave, b-wave, and oscillatory potentials (OPs) in the patients with RP were compared to those from 30 age-similar normal control subjects.

RESULTS

The amplitudes of the different components of the fmERGs in patients with RP ranged from severely reduced to normal. The degree of amplitude reduction increased as the size of the stimulus spot increased in the patients with RP. The relative amplitudes of the OPs (67% of the mean in normal subjects) were better preserved than that of the b-wave (46%) and the a-wave (39%) in a 10 degrees spot in the patients with RP.

CONCLUSIONS

The relative preservation of the OPs in the patients with RP could be due to either the buffering effect of the large receptive fields of the OP generators or to the retinal remodeling after the progressive loss of photoreceptors. Recordings of each component of fmERG can provide important information on the different layers of the central retina in RP eyes and can add to the understanding of the pathophysiology of RP.

The SDF‐1/CXCR4 ligand/receptor pair is an important contributor to several types of ocular neovascularization

Hypoxia causes increased expression of several proteins that have the potential to promote neovascularization. Vascular endothelial growth factor (VEGF) is up-regulated by hypoxia in the retina and plays a central role in the development of several types of ocular neovascularization, but the effects of other hypoxia-regulated proteins are less clear. Stromal-derived factor-1 (SDF-1) and its receptor, CXCR4, have hypoxia response elements in the promoter regions of their genes and are increased in hypoxic liver and heart. In this study, we found that SDF-1 and CXCR4 are increased in hypoxic retina, with SDF-1 localized in glial cells primarily near the surface of the retina and CXCR4 localized in bone marrow-derived cells. Glial cells also expressed CXCR4, which suggested the possibility of autocrine stimulation, but influx of bone marrow-derived cells is the major source of increased levels of CXCR4. High levels of VEGF in the retina in the absence of hypoxia also increased levels of Cxcr4 and Sdf1 mRNA. CXCR4 antagonists reduced influx of bone marrow-derived cells into ischemic retina and strongly suppressed retinal neovascularization, VEGF-induced subretinal neovascularization, and choroidal neovascularization. These data suggest that SDF-1 and CXCR4 contribute to the involvement of bone marrow-derived cells and collaborate with VEGF in the development of several types of ocular neovascularization. They provide new targets for therapeutic intervention that may help to bolster and supplement effects obtained with VEGF antagonists.

Reduction of p66Shc suppresses oxidative damage in retinal pigmented epithelial cells and retina

The largest isoform of the Shc adapter protein, p66Shc, has been implicated in oxidative damage-induced apoptosis in vital organs, because mice deficient in p66Shc have a 30% increase in life span and are resistant to the lethal effects of systemically administered paraquat, a source of severe oxidative damage. In this study, we utilized siRNA directed against the CH2 domain of Shc, to reduce p66Shc, but not p52Shc nor p46Shc in retinal pigmented epithelial (RPE) cells. RPE cells deficient in p66Shc had reduced susceptibility to oxidative stress-induced apoptosis. Compared to control cells, those with reduced p66Shc had increased basal and oxidative stress-induced NF-kappaB transcriptional activity, increased levels of antioxidant enzymes, and less generation of reactive oxygen species when challenged with H(2)O(2). The increase in oxidative stress-induced NF-kappaB activity was mediated by activation of ERK. Compared to eyes injected with GFP siRNA, those injected with p66Shc siRNA showed less loss of retinal function as assessed by electroretinograms from paraquat-induced oxidative stress. These data suggest that p66Shc and molecular signals involved in its regulation provide therapeutic targets for retinal degenerations in which oxidative-damage plays a major role, including age-related macular degeneration and cone cell death in retinitis pigmentosa.

Differential sensitivity of cones to iron-mediated oxidative damage

PURPOSE

In this study, the hypothesis that increased intraocular levels of iron cause oxidative damage to the retina was tested.

METHODS

Adult C57BL/6 mice were given an intravitreous injection of saline or 0.10, 0.25, or 0.50 mM FeSO(4). Scotopic electroretinograms (ERGs) were performed 3, 7, and 14 days after injection, and photopic ERGs were performed on day 14. Hydroethidine was used to identify superoxide radicals and lipid peroxidation was visualized by staining for hydroxynonenal (HNE). Retinal cell death was evaluated by TUNEL and measurement of inner nuclear layer (INL) and outer nuclear layer (ONL) thickness. Levels of rhodopsin and cone-opsin mRNA were measured by quantitative real time RT-PCR. Cone density was assessed by peanut agglutinin staining and confocal microscopy.

RESULTS

Compared with retinas in saline-injected eyes, retinas from eyes injected with FeSO(4) showed greater fluorescence after intravenous injection of hydroethidine due to superoxide radicals in photoreceptors, greater photoreceptor staining for HNE, a marker of lipid peroxidation, and increased expression of Heme oxygenase 1, an indicator of oxidative stress. ERG b-wave amplitudes were reduced (photopic > scotopic) in FeSO(4)-injected eyes compared with those in saline-injected eyes. Numerous TUNEL-stained nuclei were seen along the outer border of the ONL, the location of cone cell nuclei, at 1 and 2 days after injection of FeSO(4). In FeSO(4)-injected eyes, the thickness of the ONL, but not the INL, was significantly reduced, and 17 days after injection, there were 3.8- and 2.6-fold reductions in the mRNAs for M-cone and S-cone opsin, respectively, whereas there was no significant difference in rhodopsin mRNA. Confocal microscopy of peanut agglutinin-stained sections showed dose-dependent FeSO(4)-induced cone drop out.

CONCLUSIONS

Increased intraocular levels of FeSO(4) cause oxidative damage to photoreceptors with greater damage to cones than rods. This finding suggests that the oxidative defense system of cones differs from that of rods and other retinal cells, and that cones are more susceptible to damage from the type of oxidative stress imposed by iron.

VMD2 promoter requires two proximal E-box sites for its activity in vivo and is regulated by the MITF-TFE family

The retinal pigment epithelium (RPE) is crucial for the function and survival of retinal photoreceptors. VMD2 encodes bestrophin, an oligomeric chloride channel that is preferentially expressed in the RPE and, when mutated, causes Best macular dystrophy. Previously, we defined the VMD2 upstream region from -253 to +38 bp as being sufficient to direct RPE-specific expression in the eye, and we suggested microphthalmia-associated transcription factor (MITF) as a possible positive regulator. Here we show that in transgenic mice the -154 to +38 bp region is sufficient for RPE expression, and mutation of two E-boxes, 1 and 2, within this region leads to loss of promoter activity. A yeast one-hybrid screen using bait containing E-box 1 identified clones encoding MITF, TFE3, and TFEB, and chromatin immunoprecipitation with antibodies against these proteins enriched the VMD2 proximal promoter. Analysis using in vivo electroporation with constructs containing mutation of each E-box indicated that expression in native RPE requires both E-boxes, yet in vitro DNA binding studies suggested that MITF binds well to E-box 1 but only minimally to E-box 2. MITF knockdown by small interfering RNA (siRNA) in cell culture revealed a strong correlation between MITF and VMD2 mRNA levels. Sequential transfection of a luciferase construct with expression vectors following MITF siRNA revealed that TFE3 and TFEB can also transactivate the VMD2 promoter. Taken together, we suggest that VMD2 is regulated by the MITF-TFE family through two E-boxes, with E-box 1 required for a direct interaction of MITF-TFE factors and E-box 2 for binding of the as yet unidentified factor(s).

Trans-scleral delivery of polyamine analogs for ocular neovascularization

Periocular injections of the polyamine analog CGC-11144 three times a week causes regression of choroidal neovascularization. This regimen was selected to maximize chances of success for proof of concept, but is not ideal for clinical application. In this study we explored other regimens for periocular delivery of CGC-11144, and 2 other polyamine analogs, CGC-11047 and CGC-11093. A single periocular injection of 200 microg of CGC-11144, 2 mg of CGC-11047, or 1.5 mg of CGC-11093 caused significant suppression and regression of laser-induced choroidal neovascularization. An injection of 2 mg of CGC-11047 or 1.5 mg of CGC-11093 one or two weeks before, but not 3 weeks before, rupture of Bruch's membrane also caused significant suppression. Periocular injection of polyamine analogs also caused strong inhibition of retinal or subretinal neovascularization in mice with oxygen-induced ischemic retinopathy or Rhodopsin promoter/VEGF transgenic mice, respectively. These data suggest that periocular injection of one of 3 different polyamine analogs inhibits retinal or choroidal neovascularization and a single injection provides inhibitory activity for at least 2 to 3 weeks, which could provide the basis for a feasible treatment regimen for clinical trials.

Recombinant non-collagenous domain of alpha2(IV) collagen causes involution of choroidal neovascularization by inducing apoptosis

Vascular endothelial cells receive proangiogenic or antiangiogenic signals from components of extracellular matrix (ECM) depending upon the situation and many molecular signals can have opposite effects in different vascular beds. Tissue inhibitor of metalloproteinase 1 is antiangiogenic in several tissues, but promotes retinal neovascularization. When cleaved from native collagens, several of the non-collagenous domains (NC1) of basement membrane collagens have antiangiogenic effects in some tissues, but this is context dependent for the NC1 of the alpha 1 chain of collagen IV. It is critical to examine effects in several well-defined model systems before assuming that an ECM component is universally antiangiogenic. In this study, we examined the effects of a recombinant fragment of NC1 of the alpha 2 chain of type IV collagen (alpha2(IV)NC1) in a well-characterized model of ocular neovascularization. Intravitreous or periocular injections of alpha2(IV)NC1 caused selective apoptosis of endothelial cells participating in neovascularization resulting in suppression of neovascularization when the peptide was given prior to onset of new vessel sprouting. Importantly, when the peptide was given after neovascularization had already developed, it caused the new vessels to regress. This suggests that alpha2(IV)NC1, which has previously been shown to suppress tumor angiogenesis in xenograft models, is also a strong antiangiogenic agent in the choroid and is a therapeutic candidate for treatment of neovascular age-related macular degeneration.

Adeno-associated virus (AAV) capsid genes isolated from rat and mouse liver genomic DNA define two new AAV species distantly related to AAV-5

Using polymerase chain reactions and genome walking strategies, adeno-associated virus (AAV)-like capsid genes were isolated from rat and mouse liver genomic DNA, where they are present at <5 copies per cell. These genes define two new species of AAVs since their amino acid sequences are <60% identical to each other or to any other AAV capsid. They are most similar to the AAV-5 and goat AAV capsids. A recombinant vector with the mouse AAV capsid and a lacZ transgene (rAAV-mo.1 lacZ) was able to transduce rodent cell lines in vitro. However, it was not able to transduce eight human cell lines or primary human fibroblasts in vitro. It did not bind heparin and its ability to transduce cells in vitro was not inhibited by heparin, mucin, or sialic acid suggesting it uses a novel entry receptor. rAAV-mo.1 lacZ was 29 times more resistant to in vitro neutralization by pooled, purified human IgG than AAV-2. In vivo, rAAV-mo.1 lacZ efficiently transduced murine ocular cells after a subretinal injection. Intramuscular injection of a rAAV-mo.1 human factor IX (hFIX) vector into mice resulted in no detectable hFIX in plasma, but intravenous injection resulted in high plasma levels of hFIX, equivalent to that obtained from a rAAV-8 hFIX vector. Biodistribution analysis showed that rAAV-mo.1 primarily transduced liver after an intravenous injection. These AAV capsids may be useful for gene transfer in rodents.

Intraocular injection of an aptamer that binds PDGF-B: a potential treatment for proliferative retinopathies

Platelet-derived growth factor-B (PDGF-B) has been implicated in the pathogenesis of proliferative retinopathies and other scarring disorders in the eye. In this study, we sought to test the therapeutic potential of an aptamer that selectively binds PDGF-B, ARC126, and its PEGylated derivative, ARC127. Both ARC126 and ARC127 blocked PDGF-B-induced proliferation of cultured fibroblasts with an IC50 of 4 nM. Pharmacokinetic studies in rabbits showed similar peak vitreous concentrations of approximately 110 microM after intravitreous injection of 1 mg of either ARC126 or ARC127, but the terminal half-life was longer for ARC127 (98 versus 43 h). Efficacy was tested in rho/PDGF-B transgenic mice that express PDGF-B in photoreceptors and develop severe proliferative retinopathy resulting in retinal detachment. Compared to eyes injected with 20 microg of scrambled aptamer in which five of six developed detachments (three total and two partial), eyes injected with ARC126 (no detachment in five of six and one partial detachment), or ARC127 (no detachment in six of six) had significantly fewer retinal detachments. They also showed a significant reduction in epiretinal membrane formation. These data demonstrate that a single intravitreous injection of an aptamer that specifically binds PDGF-B is able to significantly reduce epiretinal membrane formation and retinal detachment in rho/PDGF-B mice. These striking effects in an aggressive model of proliferative retinopathy suggest that ARC126 and ARC127 should be considered for treatment of diseases in which PDGF-B has been implicated, including ischemic retinopathies such as proliferative diabetic retinopathy, proliferative vitreoretinopathy (PVR), and choroidal neovascularization.

Suppression and regression of choroidal neovascularization by systemic administration of an alpha5beta1 integrin antagonist

Integrin alpha(5)beta(1) plays an important role in developmental angiogenesis, but its role in various types of pathologic neovascularization has not been completely defined. In this study, we found strong up-regulation of alpha(5)beta(1) in choroidal neovascularization. Implantation of an osmotic pump delivering 1.5 or 10 microg/h ( approximately 1.8 or 12 mg/kg/day) of 3-(2-{1-alkyl-5-[(pyridin-2-ylamino)-methyl]-pyrrolidin-3-yloxy}-acetylamino)-2-(alkylamino)-propionic acid (JSM6427), a selective alpha(5)beta(1) antagonist, caused significant suppression of choroidal neovascularization; the area of neovascularization was reduced by 33 to 40%. When an osmotic pump delivering 10 microg/h of JSM6427 was implanted 7 days after rupture of Bruch's membrane, there was terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining in vascular cells within the neovascularization and significant regression of the neovascularization over the next week. JSM6427 also induced apoptosis of cultured vascular endothelial cells. Fibronectin stimulates phosphorylation of extracellular signal-regulated kinase (ERK) in alpha(5)beta(1)-expressing cells that is blocked by JSM6427. These data suggest that alpha(5)beta(1) plays a role in the development and maintenance of choroidal neovascularization and provides a target for therapeutic intervention.