Protective Effect of a Bispecific Fc-Fusion Protein on the Barrier of Human Retinal Pigment Epithelial Cells

INTRODUCTION

The aim of the study was to evaluate the protective effects of IBI302, a bispecific Fc-fusion protein that theoretically can bind vascular endothelial growth factor (VEGF), complement C3b, and C4b in the barrier of the cultured human retinal pigment epithelial (hRPE) cells.

METHODS

Primary hRPE cells were isolated and cultured to monolayer barrier. hRPE monolayers were divided into the PBS control group, VEGF-Trap group, complement receptor 1 (CR1) group, and IBI302 group. Identification of hRPE cells, barrier function, inflammation factors, and immune response products was tested by immunofluorescent staining, transepithelial resistance (TER), and ELISA.

RESULTS

IBI302 treatment significantly improved the TER of the barrier of hRPE cells after complement-activated oxidative stress compared with the PBS control group, VEGF-Trap group, and CR1 group. The maximum effect of IBI302 on protecting hRPE cell viability was observed at the concentration of 1 μg/mL. The elevated expression of VEGF, chemokine (C-C Motif) ligand 2, C3a, C5a, and membrane attack complex was reduced by IBI302.

CONCLUSION

IBI302 could protect the barrier function of hRPE cells. IBI302 might be a potentially effective drug for the RPE barrier-associated ocular diseases.

MANAGEMENT OF NEOVASCULAR OCULAR HISTOPLASMOSIS: Past and Present

PURPOSE

To review the wide variety of treatment modalities available for choroidal neovascularization secondary to the presumed ocular histoplasmosis syndrome.

METHODS

A literature search was performed to review the multitude of studies conducted to investigate the efficacy and safety of treatment modalities available for choroidal neovascularization secondary to the presumed ocular histoplasmosis syndrome.

RESULTS

Each treatment modality is reviewed, with the studies summarized and presented to support or refute the method of treatment. Two case reports are presented to demonstrate the treatment regimens.

CONCLUSION

This is a comprehensive review of the treatment modalities available to address choroidal neovascularization secondary to the presumed ocular histoplasmosis syndrome. Investigators will continue to strive toward higher efficacy and safety with future innovations in the field.

EFFICACY AND SAFETY OF RANIBIZUMAB FOR THE TREATMENT OF CHOROIDAL NEOVASCULARIZATION DUE TO UNCOMMON CAUSE: Twelve-Month Results of the MINERVA Study

Supplemental Digital Content is Available in the Text.

Ranibizumab was effective in treating choroidal neovascularization of various etiologies, with a treatment effect of +9.9 letters versus sham at Month 2 and a mean gain of 11.0 letters from baseline to Month 12. The beneficial effects of ranibizumab were observed across all etiology subgroups.

Purpose:

To evaluate the efficacy and safety of ranibizumab 0.5 mg in adult patients with choroidal neovascularization because of an uncommon cause enrolled in the 12-month MINERVA study.

Methods:

In this Phase III, double-masked study, adult (≥18 years) patients (N = 178) were randomized 2:1 to receive either ranibizumab (n = 119) or sham (n = 59) at baseline and, if needed, at Month 1 and open-label individualized ranibizumab from Month 2. Best-corrected visual acuity change from baseline to Month 2 (primary endpoint) and Month 12, treatment exposure, and safety over 12 months were reported. Subgroup analysis was conducted on five predefined choroidal neovascularization etiologies (angioid streak, postinflammatory, central serous chorioretinopathy, idiopathic, and miscellaneous).

Results:

Ranibizumab showed superior efficacy versus sham from baseline to Month 2 (adjusted least-squares mean best-corrected visual acuity: +9.5 vs. −0.4 letters; P < 0.001). At Month 12, the mean best-corrected visual acuity change was +11.0 letters (ranibizumab) and +9.3 letters (sham). Across the 5 subgroups, the treatment effect ranged from +5.0 to +14.6 letters. The mean number of ranibizumab injections was 5.8 (ranibizumab arm) with no new ocular or nonocular adverse events.

Conclusion:

Ranibizumab 0.5 mg resulted in clinically significant treatment effect versus sham at Month 2. Overall, ranibizumab was effective in treating choroidal neovascularization of various etiologies with no new safety findings.

Advanced glycation end products promote VEGF expression and thus choroidal neovascularization via Cyr61-PI3K/AKT signaling pathway

Choroidal neovascularisation (CNV) causes severe vision loss among old patients, especially those with diabetes. Previously, Cyr61 has been found to play a critical role in the pathogenesis of both AMD and diabetes. In the present study, we found that increased CNV severity together with higher expression of Cyr61 and VEGF in diabetes mice compared with control mice. Moreover, knockdown of Cyr61 decreased CNV severity. In vitro mechanism study revealed that the advanced glycation end products (AGEs) significantly increased the expression of Cyr61 in retinal pigment epithelial (RPE) cells, mimicking the effects of diabetes. In turn, the increased Cyr61 enhanced VEGF expression through FAK and PI3K/Akt pathways. Chemically blocking the above pathway significantly inhibited CNV formation, providing a new strategy for clinical prevention and treatment of CNV in related diseases.

Long-term outcomes of myopic choroidal neovascularisation treated with combined ranibizumab and dexamethasone characterised by multi-modal imaging

AIM

To characterise the long-term outcomes of myopic choroidal neovascularisation (mCNV) treated with combined ranibizumab and dexamethasone, with the use of multi-modal imaging.

METHODS

A retrospective study of 20 eyes with mCNV treated with intra-vitreal ranibizumab and dexamethasone on a treat-as-needed basis were followed up for a mean period of 47 months (range 19-81 months).

RESULTS

The mean age was 55 ± 16 years, with mean refractive error of -9.0 diopters. Subfoveal mCNV was seen in 11 eyes (52 %) and the others were juxtafoveal. At the final visit, 13 patients (65 %) had improvement, while four patients (20 %) had worsening in vision. The average number of ranibizumab and dexamethasone injections required was 3 ± 1.7. There was a significant improvement in the mean visual acuity, reduction of the central retinal thickness, and an enlargement of the area of chorioretinal atrophy. The mean rate of increase in chorioretinal atrophy area was 0.05 ± 0.09 mm²/month. Disruption of the photoreceptor layer, fragmentation of the retinal pigment epithelium, and breaks in the Bruch's membrane with a hyper-reflective lesion causing separation of the outer retinal layers were changes associated with active mCNV seen on optical coherence tomography (OCT).

CONCLUSION

Visual outcomes of mCNV treated with ranibizumab and dexamethasone on a treat-as-needed basis have favourable visual acuity outcomes. Using multi-modal imaging to monitor treatment response, chorioretinal atrophy, which may be related to visual function, should be used as an additional outcome measure to study the effect of combination treatment versus monotherapy.

Effects of core vitrectomy in the treatment of age-related macular degeneration

PURPOSE

To investigate the clinical efficacy and safety of an additional core vitrectomy to the standard therapy in patients with exudative age-related macular degeneration (ARMD).

METHODS

In this prospective, controlled, single-centre study, 50 eyes of 50 patients (mean age: 74.1 ± 7.1; median 74 (69/78)) with ARMD were enrolled and randomized 1:1 to group 1 - core vitrectomy additional to three times injections of ranibizumab (3x Rbz) and Group 2 - 3x Rbz (control). 1 16 of 25 eyes in Group 1(64%) and 12 of 25 (48%) in Group 2 had a posterior vitreous detachment (PVD) prior to start of the study. Changes in best-corrected visual acuity (BCVA) using ETDRS charts, central macular thickness and macular volume (OCT) as well as the rate of reinjection with an OCT-based pro renata (PRN) protocol were monitored prospectively over 48 weeks. Forty-seven eyes completed follow-up at week 48.

RESULTS

In Group 1, 4 of 24 lost 1 line of BCVA (16.7%) and 3 of 24 lost 2 lines (12.5%), whereas 17 of 24 gained more than 1 line (70.8%) and improved in average by 9.8 letters. In Group 2, 3 of 23 remained stable and 20 of 23 gained more than or exactly 1 line (78.3%), resulting in 14.3 letters, with no loss of lines. Central macular thickness decreased by 85.58 μm (28.8%) in Group 1 and by 121.43 μm (32.68%) in Group 2 compared with baseline. In Group 1, four patients received three additional and two patients, two additional Rbz injections. In Group 2, three patients received three additional, three patients two and 12 patients one additional Rbz injections. This yielded in an average injection rate of 3.66 in Group 1 and 4.17 in Group 2 over 48 weeks. Posterior vitreous detachment (PVD) was identified in Group 1 in 16 of 24 (66.7%) and in Group 2 in 12 of 23 (52.2%) patients at baseline. At week 48, 6 of 8 (75%) of the patients in Group 1 with initial attached vitreous showed a vitreal detachment, whereas only 1 of 11 (9%) in Group 2 had a new occurred detachment of the vitreous. No systemic or ocular adverse events were noticed.

CONCLUSION

An initial core vitrectomy combined with a conventional ranibizumab injection regimen for exudative AMD patients was safe and lead to similar functional results with less intravitreal ranibizumab injections over 48 weeks.

C-reactive protein and complement components in patients with pathological myopia

PURPOSE

To investigate the association between pathological myopia (PM) and immunological/inflammatory markers and to identify the possible risk factors for the formation of myopic choroidal neovascularization (mCNV).

METHODS

One hundred fourteen unrelated subjects were recruited: 63 PM patients (PM group) with spherical equivalent of at least -8.00 diopters (range, -8.00 to -25.00) and axial length exceeding 26.5 mm, accompanied by characteristic pathologic changes, and 51 emmetropic age- and sex-matched individuals (control group) with spherical equivalent within ±1.0 diopter in both eyes. In the PM group, patients were assigned to two subgroups, mCNV group and no CNV group, according to the results of fluorescein angiography. Serum high-sensitivity C-reactive protein (hs-CRP) and complement profile (C3, C4, and CH50) were assayed. Statistical analysis was performed between the two groups. Binary logistic regression analysis was used to analyze the relative risk factors that were associated with the development of mCNV in the PM group patients.

RESULTS

The range of axial length was 26.50 to 37.08 mm in the PM group and 22.32 to 24.56 mm in the control group. There were 24 patients in the mCNV group and 39 patients in the no CNV group. The PM group patients had significantly higher serum hs-CRP (p = 0.033), C3 (p = 0.004), and CH50 (p < 0.001) compared with the control group patients. There were no significant differences between the two groups for C4 level (p = 0.071). Binary logistic regression analysis, which included hs-CRP, C3, C4, CH50, age, and sex as covariates, showed that C3 (p = 0.03) and age (p = 0.01) were risk factors for mCNV, whereas serum hs-CRP, C4, CH50, and sex were not statistically significant predictors of mCNV in the PM group patients (p > 0.05).

CONCLUSIONS

Our data support the hypothesis that immunological/inflammatory markers, namely hs-CRP, C3, and CH50 may play an important role in the development of PM, and that C3 level may be a predictive risk factor for mCNV formation.

Immunohistochemistry of angiogenesis mediators before and after pulsed dye laser treatment of angiomas

BACKGROUND AND OBJECTIVE

Tissue effects of vascular lesion laser treatment are incompletely understood. Injury caused by pulsed dye laser (PDL) treatment may result in altered expression of mediators associated with angiogenesis.

MATERIALS AND METHODS

Eight human subjects had one angioma treated with PDL (7 mm, 1.5 millisecond pulse duration, 9 J/cm(2), cryogen spray cooling of 30 millisecond with a 30 millisecond delay). One week later, three biopsies were taken: normal skin, untreated angioma, angioma post-PDL. Tissue was frozen and sections processed for immunohistochemistry staining of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), matrix metalloproteinase 9 (MMP-9), and angiopoietin 2 (ANG-2). Images were graded in a blinded fashion by a board certified dermatopathologist.

RESULTS

There were no clear trends in VEGF expression in the epidermis, dermis, or endothelial cells. As compared to normal skin, angiomas demonstrated the following: bFGF was decreased in the epidermis; MMP-9 was decreased or unchanged in the epidermis and increased in the endothelial cells; ANG-2 was increased in the endothelial cells. When comparing normal skin to angiomas + PDL, bFGF was decreased in the epidermis and increased in the dermis; MMP-9 was decreased or unchanged in the epidermis; ANG-2 was again increased in the endothelial cells. Comparison of staining in angioma to angioma + PDL samples revealed increased dermal bFGF expression.

CONCLUSION

Alterations in angiogenesis mediators were noted after PDL. Angiogenesis mediator changes associated with PDL treatment differed from those previously reported for incisional biopsies. This pilot study can guide future work on laser-induced alterations in vascular lesions and such information may ultimately be used to optimize treatment outcomes.

Quadruple therapy leads to a sustained improvement of vision in patients with wet age-related macular degeneration

AIM

To investigate the efficacy of a combined intravitreal therapy with prior photodynamic therapy (PDT) in patients with wet age-related macular degeneration.

METHODS

Fifty-two patients (mean age: 72.7 years) with predominantly classic choroidal neovascularization received low-fluence PDT (42 J/cm2 for 72 s), followed 24 h later by a 0.4-ml core pars plana vitrectomy with intravitreal injection of dexamethasone (0.8 mg) and bevacizumab (1.25 mg). The best-corrected visual acuity (BCVA; 6 m Snellen), central macular thickness (optical coherence tomography), intraocular pressure and the need for retreatment were assessed.

RESULTS

BCVA changed significantly (vs. baseline) at 3 months (+0.11), 9 months (+0.19) and 14 months (+0.16). At the end of the follow-up period, BCVA had improved by > 0.1 in the majority of the patients (72.9%), and the mean central retinal thickness had decreased by -44.3% (-211 μm). The retreatment rate was 25%. No increase in intraocular pressure or other adverse event was reported.

CONCLUSIONS

The pharmacological effects of the drugs, the low-fluence PDT, and the physiological effects of the therapy may have contributed to the sustainability of the therapeutic benefits.

Combination therapy using verteporfin and ranibizumab; optimizing the timing in the CAM model

Combining photodynamic therapy (PDT) using verteporfin (Visudyne) with ranibizumab (Lucentis) can optimize the overall treatment outcome by providing more efficacy in vessel closure, and thus reduce the need for retreatment in patients with wet age-related macular degeneration. In this preclinical study in the chorioallantoic membrane (CAM) of the chicken embryo, we compare the vascular occlusion effects of verteporfin and ranibizumab as monotherapies with those observed in the combined therapy. In order to optimize the combination therapy, we varied the timing and sequence of the PDT and antivascular endothelial growth factor modalities. We observed that 1 day after PDT, the smaller blood vessels (Ø < 70 microm) of the CAM were selectively occluded, but as early as 2 days after PDT, both significant reperfusion and regrowth of new vessels were observed. Both these phenomena could be significantly delayed by application of ranibizumab. Ranibizumab itself did not induce any vascular occlusion. Under the applied conditions of combination therapy, the occlusion of the targeted blood vessels could be significantly extended to 3 days in this model compared with 1 day in the case of verteporfin monotherapy. Thus, in the present preclinical study, we demonstrate that for the applied conditions, the optimal time to administer ranibizumab is 24 h after PDT.

Interaction of intravitreal combination drugs and the effect on the targeted site

BACKGROUND

After evaluating experimentally the diffusion processes in the retina using peroxidase as a tracer material (previously published work), we found that junctional complexes of the retinal pigment epithelium and retinal capillaries were the major impediment to free diffusion between the retina and choroidal-retinal blood vessels. These experiments indicated that to achieve high therapeutic concentrations of medications inside the eye, it was necessary to administer them by intravitreal injection. Soon after initial experimental work the necessity of combining antibiotics or antibiotics with steroids became obvious. As the use of intravitreal injection grew over the last 2 decades, so did the concept of combination therapy.

METHODS

This review describes potential causes of drug-drug interaction and the rationale for combination therapy when injected into the vitreous cavity, encompassing publications between 1971 and 2008.

RESULTS

We describe the conditions that can cause physical-chemical interactions between the medications and the need for combination therapy for treatment of various intraocular disease processes.

CONCLUSIONS

The intravitreal injection of medication and their combinations has become a part of standard care for many diseases of the retina and choroid. This article reviews the potential interaction of nontoxic doses of medications when injected simultaneously in the vitreous cavity, and disease processes that are now treated with these combination therapies.