scholarly journals A new rat model of treatment-naive quiescent choroidal neovascularization induced by human VEGF165 overexpression

Biology Open ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. bio048736 ◽  
Author(s):  
Shan Liu ◽  
Antje K. Biesemeier ◽  
Alexander V. Tschulakow ◽  
Harsh V. Thakkar ◽  
Sylvie Julien-Schraermeyer ◽  
...  
Keyword(s):  
Choroidal Neovascularization ◽  
Rat Model ◽  
Retinal Pigment ◽  
Basement Membranes ◽  
Age Related Macular Degeneration ◽  
New Drugs ◽  
Short Term Treatment ◽  
Age Related ◽  
Treatment Naïve

ABSTRACTVascular endothelial growth factor (VEGF) is a crucial stimulator for choroidal neovascularization (CNV). Our aim was to develop a reproducible and valid treatment-naive quiescent CNV (i.e. without signs of exudation and with normal visual acuity) rat model by subretinal injection of an adeno-associated virus (AAV)-VEGFA165 vector. The CNV development was longitudinally followed up in vivo by scanning laser ophthalmoscopy/optical coherence tomography, fluorescein and Indocyanine Green angiographies and ex vivo by electron microscopy (EM) and immunohistochemistry. In total, 57 eyes were analysed. In vivo, a quiescent CNV was observed in 93% of the eyes 6 weeks post-transduction. In EM, CNV vessels with few fenestrations, multi-layered basement membranes and bifurcation of endothelial cells were observed sharing the human CNV features. Human VEGF overexpression, multi-layered retinal pigment epithelium (RPE) (RPE65) and macrophages/activated microglia (Iba1) were also detected. In addition, 19 CNV eyes were treated for up to 3 weeks with bevacizumab. The retinal and CNV lesion thickness decreased significantly in bevacizumab-treated CNV eyes compared with untreated CNV eyes 1 week after the treatment. In conclusion, our experimental CNV resembles those seen in patients suffering from treatment-naive quiescent CNV in wet age-related macular degeneration (AMD), and responds to short-term treatment with bevacizumab. Our new model can, therefore, be used to test the long-term effect of new drugs targeting CNV under precisely-defined conditions.

scholarly journals Optimal Inhibition of Choroidal Neovascularization by scAAV2 with VMD2 Promoter-driven Active Rap1a in the RPE

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Haibo Wang ◽  
Eric Kunz ◽  
Gregory J. Stoddard ◽  
William W. Hauswirth ◽  
M. Elizabeth Hartnett
Keyword(s):  
Choroidal Neovascularization ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Term Treatment ◽  
Age Related Macular Degeneration ◽  
Promising Tool ◽  
Age Related ◽  
Long Term Treatment

Abstract Age-related macular degeneration (AMD) is a multifactorial chronic disease that requires long term treatment. Gene therapy is being considered as a promising tool to treat AMD. We found that increased activation of Rap1a in the retinal pigment epithelium (RPE) reduces oxidative signaling to maintain barrier integrity of the RPE and resist neural sensory retinal angiogenesis from choroidal endothelial cell invasion. To optimally deliver constitutively active Rap1a (CARap1a) into the RPE of wild type mice, self-complementary AAV2 (scAAV2) vectors driven by two different promoters, RPE65 or VMD2, were generated and tested for optimal active Rap1a expression and inhibition of choroidal neovascularization (CNV) induced by laser injury. scAAV2-VMD2, but not scAAV2-RPE65, specifically and efficiently transduced the RPE to increase active Rap1a protein in the RPE. Mice with increased Rap1a from the scAAV2-VMD2-CARap1a had a significant reduction in CNV compared to controls. Increased active Rap1a in the RPE in vivo or in vitro inhibited inflammatory and angiogenic signaling determined by decreased activation of NF-κB and expression of VEGF without causing increased cell death or autophagy measured by increased LCA3/B. Our study provides a potential future strategy to deliver active Rap1a to the RPE in order to protect against both atrophic and neovascular AMD.

scholarly journals Crosstalk between RPE cells and choroidal endothelial cells via the ANXA1/FPR2/SHP2/NLRP3 inflammasome/pyroptosis axis promotes choroidal neovascularization

2021 ◽  
Author(s):  
Manhui Zhu ◽  
Ying Wang ◽  
Linling Zhu ◽  
Shu Du ◽  
Zhenzhen Wang ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Choroidal Neovascularization ◽  
Nlrp3 Inflammasome ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Inflammasome Activation ◽  
Rpe Cells ◽  
Age Related

Abstract One type of age-related macular degeneration (AMD), neovascular (nAMD), characterized by choroidal neovascularization (CNV), accounts for the majority of the severe central vision impairment associated with AMD. Endothelial cells (ECs) in direct contact with retinal pigment epithelial (RPE) cells are more prone to the pathological angiogenesis involved in CNV. Herein, we investigated the effect of crosstalk between RPE cells and choroidal endothelial cells (CECs) via the ANXA1/FPR2/NLRP3 inflammasome/pyroptosis axis on the development of choroidal neovascularization (CNV) in vitro and in vivo. ANXA1 expression and secretion from ARPE-19 cells were upregulated by hypoxia. FPR2 expression, especially on the plasma membrane, in HCECs was upregulated under hypoxic conditions. ANXA1 secreted from ARPE-19 cells inhibited NLRP3 inflammasome activation and NLRP3 inflammasome-mediated pyroptosis in HCECs by activating the FPR2/SHP2 axis. Moreover, ANXA1 secreted by ARPE-19 cells promoted behaviors of HCECs, including proliferation, migration and tube formation, by activating the FPR2/SHP2 axis and inhibiting NLRP3 inflammasome-mediated pyroptosis. Inhibiting the upregulated ANXA1/FPR2/SHP2/NLRP3 inflammasome/pyroptosis axis decreased the volume of CNV. Our data suggest that the crosstalk between RPE cells and CECs via the ANXA1/FPR2/NLRP3 inflammasome/pyroptosis axis promotes CNV. This finding could identify a potential target for the prevention and treatment of CNV.

scholarly journals A novel ferrochelatase inhibitor as a therapy for ocular neovascularization

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Sydney Waller ◽  
Sheik Pran Babu Sardar Pasha ◽  
Nathan Lambert-Cheatham ◽  
Timothy W. Corson
Keyword(s):  
Optical Coherence Tomography ◽  
Choroidal Neovascularization ◽  
High Throughput Screening ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Optical Coherence ◽  
Ocular Neovascularization ◽  
Age Related

Background and Hypothesis: Ocular neovascularization, characterized by the abnormal growth of new blood vessels, underlies blindness-inducing diseases such as wet age-related macular degeneration (AMD) and proliferative diabetic retinopathy (PDR). This neovascularization can be either choroidal (in the case of wet AMD) or retinal (in the case of PDR). Inhibition of vascular endothelial growth factor is the target of current FDA approved therapies, however the need for intravitreal injections poses a drawback to such treatments. Furthermore, many patients are non-responders or refractory. Given this, the discovery of novel therapeutic targets is warranted. Ferrochelatase (FECH) is an enzyme involved in heme synthesis. The Corson lab has previously shown FECH to be necessary for angiogenesis both in vitro and in vivo. The Corson lab has been successful in developing novel compounds that inhibit FECH in vitro, based on high-throughput screening hits. The objective of this project was to test one such novel FECH inhibitor in a choroidal neovascularization mouse model. Experimental Design: FECH inhibition was investigated in the laser-induced choroidal neovascularization model. This model involved creating a laser-induced lesion into the retinal pigment epithelium/choroid of mice aged 6-8 weeks; this promotes neovascularization. The FECH inhibitor compound was delivered once intravitreally at the time of the laser. Neovascularization was analyzed in vivo using optical coherence tomography and fluorescein angiography one and two weeks after laser, then quantified ex vivo by isolectin staining. Results: There was a trend toward decreased ocular neovascularization with the administration of a FECH inhibitor, as measured by optical coherence tomography seven days after laser treatment. However, further analyses are ongoing to validate this finding. Conclusion and Potential Impact: The administration of a FECH inhibitor compound intravitreally may result in a decrease in CNV. This may be useful as it could lead to FECH serving as a target for future therapies.

scholarly journals Complement C5 is not critical for the formation of sub-RPE deposits in Efemp1 mutant mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Donita L. Garland ◽  
Eric A. Pierce ◽  
Rosario Fernandez-Godino
Keyword(s):  
Macular Degeneration ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Deposit Formation ◽  
Genetic Ablation ◽  
Age Related ◽  
Complement Dysregulation

AbstractThe complement system plays a role in the formation of sub-retinal pigment epithelial (RPE) deposits in early stages of age-related macular degeneration (AMD). But the specific mechanisms that connect complement activation and deposit formation in AMD patients are unknown, which limits the development of efficient therapies to reduce or stop disease progression. We have previously demonstrated that C3 blockage prevents the formation of sub-RPE deposits in a mouse model of EFEMP1-associated macular degeneration. In this study, we have used double mutant Efemp1R345W/R345W:C5-/- mice to investigate the role of C5 in the formation of sub-RPE deposits in vivo and in vitro. The data revealed that the genetic ablation of C5 does not eliminate the formation of sub-RPE deposits. Contrarily, the absence of C5 in RPE cultures promotes complement dysregulation that results in increased activation of C3, which likely contributes to deposit formation even in the absence of EFEMP1-R345W mutant protein. The results also suggest that genetic ablation of C5 alters the extracellular matrix turnover through an effect on matrix metalloproteinases in RPE cell cultures. These results confirm that C3 rather than C5 could be an effective therapeutic target to treat early AMD.

scholarly journals Role of Activating Transcription Factor 4 in Murine Choroidal Neovascularization Model

2021 ◽  
Vol 22 (16) ◽  
pp. 8890
Author(s):  
Hiroto Yasuda ◽  
Miruto Tanaka ◽  
Anri Nishinaka ◽  
Shinsuke Nakamura ◽  
Masamitsu Shimazawa ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Transcription Factor ◽  
Er Stress ◽  
Choroidal Neovascularization ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Activating Transcription Factor 4 ◽  
Age Related ◽  
Activating Transcription Factor ◽  
Transcription Factor 4

Neovascular age-related macular degeneration (nAMD) featuring choroidal neovascularization (CNV) is the principal cause of irreversible blindness in elderly people in the world. Integrated stress response (ISR) is one of the intracellular signals to be adapted to various stress conditions including endoplasmic reticulum (ER) stress. ISR signaling results in the upregulation of activating transcription factor 4 (ATF4), which is a mediator of ISR. Although recent studies have suggested ISR contributes to the progression of some age-related disorders, the effects of ATF4 on the development of CNV remain unclear. Here, we performed a murine model of laser-induced CNV and found that ATF4 was highly expressed in endothelial cells of the blood vessels of the CNV lesion site. Exposure to integrated stress inhibitor (ISRIB) reduced CNV formation, vascular leakage, and the upregulation of vascular endothelial growth factor (VEGF) in retinal pigment epithelium (RPE)-choroid-sclera complex. In human retinal microvascular endothelial cells (HRMECs), ISRIB reduced the level of ATF4 and VEGF induced by an ER stress inducer, thapsigargin, and recombinant human VEGF. Moreover, ISRIB decreased the VEGF-induced cell proliferation and migration of HRMECs. Collectively, our findings showed that pro-angiogenic effects of ATF4 in endothelial cells may be a potentially therapeutic target for patients with nAMD.

The Effects of Indocyanine Green Dye-Enhanced Photocoagulation on the Blood Flow in the Choriocapillaris and the Choroidal Neovascularization (CNV)

2000 ◽  
Author(s):  
C. von Kerczek ◽  
L. Zhu ◽  
A. Ernest ◽  
C. Eggleton ◽  
L. D. T. Topoleski ◽  
...  
Keyword(s):  
Laser Treatment ◽  
Choroidal Neovascularization ◽  
Vision Loss ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
The United States ◽  
Age Related Macular Degeneration ◽  
Central Vision ◽  
Age Related ◽  
Direct Laser

Abstract Age-related macular degeneration (AMD) is the most common cause of vision loss in patients aged 65 years and older in the United States. In the majority of cases, the loss of central vision is secondary to exudative changes and fibrovascular scarring following choroidal neovascularization (CNV). Prompt laser treatment is recommended [Asrani et al., 1996; Macular Photocoagulation Study Group, 1993; Schneider et al, 1998]. However, direct laser treatment to the entire subfoveal lesion is almost invariably associated with immediate loss of central vision. Loss of central vision may be due to direct damage to foveal photoreceptors and retinal pigment epithelium or from damage to the nerve fiber layer serving foveal function [Han et al., 1988].

Cell-based therapy for ocular disorders: A promising frontier

2021 ◽  
Vol 16 ◽  
Author(s):  
Milad Ahani-Nahayati ◽  
Vahid Niazi ◽  
Alireza Moradi ◽  
Bahareh Pourjabbar ◽  
Reza Roozafzoon ◽  
...  
Keyword(s):  
Stem Cells ◽  
Wide Spectrum ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Ocular Tissue ◽  
Ocular Diseases ◽  
Cell Based Therapy ◽  
Age Related ◽  
Ocular Disorders

: As the ocular disorders causing long-term blindness or optical abnormalities of the ocular tissue affect the quality of life of patients to a large extent, awareness of their corresponding pathogenesis and the earlier detection and treatment need more consideration. Though current therapeutics result in desirable outcomes, they do not offer an inclusive solution for development of visual impairment to blindness. Accordingly, stem cells, because of their particular competencies, have gained extensive attention for application in regenerative medicine of ocular diseases. In the last decades, a wide spectrum of stem cells surrounding mesenchymal stem/stromal cells (MSC), neural stem cells (NSCs), and embryonic/induced pluripotent stem cells (ESCs/iPSCs) accompanied by Müller glia, ciliary epithelia-derived stem cells, and retinal pigment epithelial (RPE) stem cells have been widely investigated to report their safety and efficacy in preclinical models and also human subjects. In this regard, in the first interventions, RPE cell suspensions were successfully utilized to ameliorate visual defects of the patients suffering from age-related macular degeneration (AMD) after subretinal transplantation. Herein, we will explain the pathogenesis of ocular diseases and highlight the novel discoveries and recent findings in the context of stem cell-based therapies in these disorders, focusing on the in vivo reports published during the last decade.

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