Topical bevacizumab for neovascular glaucoma: a pilot study

[Pharmacological modulation of wound healing in glaucoma surgery]

Despite the well-known effectiveness of pharmacological glaucoma therapy, surgical approach remains one of the main treatment options for some forms and stages of the disease. The long-term success of glaucoma surgery depends on the intensity of local wound healing processes at the surgical site. The most common way to influence healing processes in surgical treatment of glaucoma is the use of antimetabolites. However, given the high risk of serious complications associated with their use, the search for new drugs devoid of these disadvantages continues. The aim of this review is to describe the efficacy and safety of both currently used and upcoming pharmacological ways to influence the wound healing process after glaucoma surgery in order to improve the stability of hypotensive effect.

Impact of photoreceptor density in a 3D simulation of panretinal laser photocoagulation

Background

During panretinal photocoagulation (PRP), the outer retina, especially the photoreceptors, are destroyed. During such procedures, the impact of the retinal photocoagulation, which is performed in the same photocoagulated area, may change if it is applied to different locations with different photoreceptor densities. Thus, we aimed to evaluate the influence of photoreceptor density on PRP.

Methods

We constructed a three-dimensional (3D) average distribution of photoreceptors with 3D computer-aided design (CAD) software using previously derived photoreceptor density data and calculated the number of photoreceptors destroyed by scatter PRP and full-scatter PRP (size 400-μm on the retina, spacing 1.0 spot) using a geometry-based simulation. To investigate the impact of photoreceptor density on PRP, we calculated the ratio of the number of photoreceptors destroyed to the total number of photoreceptors, termed the photoreceptor destruction index.

Results

In this 3D simulation, the total number of photoreceptors was 96,571,900. The total number of photoreceptors destroyed by scatter PRP and full-scatter PRP were 15,608,200 and 19,120,600, respectively, and the respective photoreceptor destruction indexes were 16.2 and 19.8%, respectively.

Conclusions

Scatter PRP is expected to have 4/5 of the number of photoreceptors destroyed by full-scatter PRP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-01945-z.

[Anti-VEGF drugs in the treatment of neovascular glaucoma]

Neovascular glaucoma (NVG) is the most frequently occurring type of secondary glaucoma characterized by significant decrease in visual functions. Its pathogenesis consists mainly of ischemia of the posterior segment, which is often secondary to proliferative diabetic retinopathy or ischemic central retinal vein occlusion. Development of neovascularization in the eye is associated with processes that change homeostatic balance between proangiogenic (vascular endothelial growth factor (VEGF)) and antiangiogenic (pigment epithelium-derived factor (PEDF)) factors. The aim of the therapy is to reduce the production of aqueous humour. Application of antiangiogenic preparations in patients with NVG as adjuvant therapy is the method of choice for both prevention and treatment of the disease. The article reviews literature on current possibilities of using anti-VEGF drugs in the treatment of NVG.

Use of Anti-VEGF Agents in Glaucoma Surgery

A number of antivascular endothelial growth factor agents are currently available to treat various ocular conditions. These agents have similar, but distinct, biologic qualities and have been explored in the management of neovascular glaucoma and in glaucoma surgery. Several different delivery methods are described, and because these medications are routinely given as intraocular injections, some benefits over traditional antifibrotic medications when used in glaucoma surgery are noted. These agents effectively induce regression of anterior segment neovascularization and facilitate initial surgical management of neovascular glaucoma, but the long-term outcome of this condition remains dependent on definitive management of the underlying process. Use in trabeculectomy or tube shunt procedures for other types of glaucoma has shown promise in modulating bleb morphology but has not yet been found to be as effective as traditional antifibrotic agents. There are reports of persistently raised intraocular pressure after repeated use of the anti-VEGF agents, possibly related to frequency of injection. These medications have wide application in the field of surgical glaucoma, but a definitive role has yet to be defined.

Efficacy and safety of intravitreal ranibizumab with panretinal photocoagulation followed by trabeculectomy compared with Ahmed glaucoma valve implantation in neovascular glaucoma

AIM

To evaluate the efficacy and safety of intravitreal ranibizumab (IVR) with panretinal photocoagulation (PRP) followed by trabeculectomy compared with Ahmed glaucoma valve (AGV) implantation in neovascular glaucoma (NVG).

METHODS

This was a retrospective comparative study. We reviewed the cases of a total of 45 eyes from 45 NVG patients among which 23 eyes underwent AGV implantation and the other 22 underwent trabeculectomy. The causes of neovascular glaucoma included: diabetic retinopathy (25 eyes), and retinal vein occlusion (20 eyes). All patients received preoperative IVR combined with postoperative PRP. The mean best-corrected visual acuities (BCVA) were converted to the logarithms of the minimum angle of resolution (logMAR) for the statisitical analyses. Intraocular pressure (IOP), the logMAR BCVA and surgical complications were evaluated before and after surgery. The follow-up period was 12mo.

RESULTS

A total of 39 cases showed complete regression of iris neovascularization at 7d after injection, and 6 cases showed a small amount of residual iris neovascularization. The success rates were 81.8% and 82.6% at 12mo after trabeculectomy and AGV implantation, respectively. In the trabeculectomy group, the logMAR BCVA improved at the last follow-up in 14 eyes, remained stable in 6 eyes and decreased in 2 eyes. In 4 cases, slight hyphemas developed after trabeculectomy. A shallow anterior chamber developed in 2 cases and 2 vitreous hemorrhages. In the AGV group, the logMAR BCVA improved in 14 eyes, remained stable in 5 eyes and decreased in 4 eyes. Slight hyphemas developed in 3 cases, and a shallow anterior chamber in 3 cases. The mean postoperative IOP was significantly lower in both groups after surgery (F=545.468, P<0.05), and the mean postoperative logMAR BCVA was also significantly improved (F=10.964, P<0.05) with no significant difference between two groups.

CONCLUSION

It is safe and effective to treat NVG with this combined procedure, and we found similar results after IVR+AGV implantation+PRP and IVR+trabeculectomy+PRP in eyes with NVG.

Current Perspectives on the Use of Anti-VEGF Drugs as Adjuvant Therapy in Glaucoma

The approval of one of the first anti-vascular endothelial growth factor (VEGF) agents for the treatment of neovascular age-related macular degeneration one decade ago marked the beginning of a new era in the management of several sight-threatening retinal diseases. Since then, emerging evidence has demonstrated the utility of these therapies for the treatment of other ocular conditions characterized by elevated VEGF levels. In this article we review current perspectives on the use of anti-VEGF drugs as adjuvant therapy in the management of neovascular glaucoma (NVG). The use of anti-VEGFs for modifying wound healing in glaucoma filtration surgery (GFS) is also reviewed. Selected studies investigating the use of anti-VEGF agents or antimetabolites in GFS or the management of NVG have demonstrated that these agents can improve surgical outcomes. However, anti-VEGF agents have yet to demonstrate specific advantages over the more established agents commonly used today. Further studies are needed to evaluate the duration of action, dosing intervals, and toxicity profile of these treatments.

Repositioning Bevacizumab: A Promising Therapeutic Strategy for Cartilage Regeneration

Drug discovery and development has been garnering an increasing trend of research due to the growing incidence of the diverse types of diseases. Recently, drug repositioning, also known as drug repurposing, has been emerging parallel to cancer and tissue engineering studies. Drug repositioning involves the application of currently approved or even abandoned drugs as alternative treatments to other diseases or as biomaterials in other fields including cell therapy and tissue engineering. In this review, the advancement of the antiangiogenesis drugs that were used as treatment for cancer and other diseases, with particular focus on bevacizumab, will be described. This will include an overview of the nature and progression of osteoarthritis (OA), one of the leading global degenerative diseases that cause morbidity, and the development of its therapeutic strategies. In addition, this will also feature the nonsteroidal anti-inflammatory drugs that are commonly prescribed for OA and the benefits of repositioning bevacizumab as alternative treatments for other diseases and as biomaterials for cartilage regeneration. To date, a few number of studies, employing different modes of administration and varying dosages in diverse animal models, have shown that bevacizumab can be used as a signal and can promote both in vitro and in vivo cartilage regeneration. However, other antiangiogenesis drugs and their effects in chondrogenesis and cartilage regeneration are also worth investigating.

Ranibizumab Plus Combined Surgery for Treatment of Neovascular Glaucoma with Vitreous Hemorrhage

Background:

Neovascular glaucoma (NVG) is a refractory glaucoma. The management of NVG is very difficult, and it is more difficult when combined with vitreous hemorrhage. The aim of this study was to investigate the effects of ranibizumab plus combined surgery for NVG with vitreous hemorrhage.

Methods:

A total of 26 eyes of 26 NVG patients with vitreous hemorrhage were recruited in this study. The patients aged from 36 to 63 years with a mean age of 51.97 ± 7.60 years. The mean intraocular pressure (IOP) was 46.38 ± 5.75 mmHg (1 mmHg = 0.133 kPa) while being treated with the maximum medical therapy. The mean best-corrected visual acuities converted to logarithm of the minimum angle of resolution (logMAR BCVA) was 2.62 ± 0.43. All the patients underwent intravitreal injection of 0.5 mg (0.05 ml) ranibizumab combined with pars plana vitrectomy (PPV), pars plana lensectomy (PPL) with a preserved anterior capsule, panretinal photocoagulation (PRP), and trabeculectomy (intravitreal ranibizumab [IVR] + PPV + PPL + PRP + trabeculectomy). The IOP and logMAR BCVA were the main outcome measures in this study.

Results:

The follow-up period was 12 months. The mean postoperative IOPs were 26.38 ± 3.75 mmHg, 21.36 ± 3.32 mmHg, 18.57 ± 3.21 mmHg, and 16.68 ± 2.96 mmHg, respectively at 7 days, 1 month, 3 months, and 12 months after PPV + PPL + PRP + trabeculectomy. At the last follow-up, the mean IOP was significantly lower than the preoperative one (t = 6.612, P = 0.001). At 7 days, 1 month, 3 months, and 12 months after PPV + PPL + PRP + trabeculectomy, the mean logMAR BCVA were 1.30 ± 0.36, 1.29 ± 0.37, 1.29 ± 0.39, and 1.26 ± 0.29, respectively. At the last follow-up, the mean logMAR BCVA was significantly improved, and the difference was statistically significant compared with preoperative one (t = 6.133, P = 0.002). The logMAR BCVA improved in 22 eyes (84.62%), and remained stable in 4 eyes (15.38%). The neovascularization in the iris and the angle regressed significantly in all patients 7 days after ranibizumab injection. No serious complications occurred during 12 months of the study.

Conclusions:

IVR + PPV + PPL + PRP + trabeculectomy can control IOP well and improve BCVA without severe complication for NVG patients with vitreous hemorrhage.

Angiogenesis in glaucoma filtration surgery and neovascular glaucoma: A review

Angiogenesis may pose a clinical challenge in glaucoma, for example, during the wound healing phase after glaucoma filtration surgery and in the severe secondary glaucoma called neovascular glaucoma (NVG). Upregulation of vascular endothelial growth factor (VEGF), a key mediator of angiogenesis, occurs in eyes that have undergone glaucoma filtration surgery, as well as those with NVG. This has led investigation of the ability of anti-vascular endothelial growth factor therapy to improve outcomes, and we examine the findings with respect to the safety and efficacy of anti-vascular endothelial growth factor agents, mainly bevacizumab and ranibizumab, in eyes that have undergone glaucoma filtration surgery or have NVG. Combining conventional therapies-such as antimetabolites after filtration surgery and panretinal photocoagulation in NVG-and anti-vascular endothelial growth factor drugs may produce a synergetic effect, although further studies are required to evaluate the long-term efficacy of combination treatments.

MicroRNA miR-466 inhibits Lymphangiogenesis by targeting prospero-related homeobox 1 in the alkali burn corneal injury model

Background

Lymphangiogenesis is one of the major causes of corneal graft rejection. Among the lymphangiogenic factors, vascular endothelial growth factor (VEGF)-C and -D are considered to be the most potent. Both bind to VEGF receptor 3 (VEGFR3) to activate Prospero homeobox 1 (Prox1), a transcription factor essential for the development and maintenance of lymphatic vasculature. MicroRNAs (miRNAs) bind to the 3' untranslated regions (3' UTRs) of target genes in a sequence-specific manner and suppress gene expression. In the current study, we searched for miRNAs that target the pro-lymphangiogenic factor Prox1.

Results

Among the miRNAs predicted by the bioinformatic analysis to seed match with the 3' UTR of Prox-1, we chose 3 (miR-466, miR-4305, and miR-4795-5p) for further investigation. Both the miR-466 and miR-4305 mimics, but not the miR-4795-5p mimic, significantly reduced the luciferase activity of the Prox-1 3' UTR reporter vector. In primary lymphatic endothelial cells (HDLEC), miR-466 mimic transfection suppressed Prox1 mRNA and protein expression, while miR-4305 mimic transfection did not. Experiments using mutated reporter constructs of the two possible seed match sites on the 3' UTR of Prox1 suggested that the target site 2 directly bound miR-466. HDLEC transfected with the miR-466 mimic suppressed tube formation as compared to the scrambled control. Furthermore, HDLEC transfected with a miR-466 inhibitor showed enhanced tube formation as compared to control inhibitor transfected cells, and this inhibitory effect was counteracted by Prox1 siRNA. The miR-466 mimic reduced angiogenesis and lymphangiogenesis resulting in clearer corneas in an cornea injury rat model compared to the scrambled control.

Conclusions

Our data suggest that miR-446 may have a protective effect on transplanted corneas by suppressing Prox1 expression at the post-transcriptional level. The results of the current study may provide insights into the mechanisms of lymphangiogenesis resulting from corneal graft rejection and alkali-burn injuries, as well as into the development of new treatments for lymphangiogenic eye diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s12929-014-0104-0) contains supplementary material, which is available to authorized users.

Applications and implications of heparin and protamine in tissue engineering and regenerative medicine

Drug repositioning is one of the most rapidly emerging fields of study. This concept is anchored on the principle that diseases have similar damaged or affected signaling pathways. Recently, drugs have been repositioned not only for their alternative therapeutic uses but also for their applications as biomaterials in various fields. However, medical drugs as biomaterials are rarely focused on in reviews. Fragmin and protamine have been recently the sources of increasing attention in the field of tissue engineering and regenerative medicine. Fragmin and protamine have been manufactured primarily as a safe antidote for the circulating heparin. Lately, these drugs have been utilized as either micro- or nanoparticle biomaterials. In this paper, we will briefly describe the concept of drug repositioning and some of the medical drugs that have been repurposed for their alternative therapeutic uses. Also, this will feature the historical background of the studies focused on fragmin/protamine micro/nanoparticles (F/P M/NPs) and their applications as biomaterials in tissue engineering, stem cell therapy, and regenerative medicine.