Effects of ranibizumab (Lucentis®) and bevacizumab (Avastin®) on human corneal endothelial cells

Long-term dynamic changes and influencing factors of corneal morphology after multiple intravitreal injections of anti-VEGF drugs

To observe alterations in corneal morphology caused by repeated intravitreal injections of anti-vascular endothelial growth factor (VEGF). Prospective cohort study. Seventy-seven eyes were treated with intravitreal injection of anti-VEGF from June 2021 to March 2023. There were 25 eyes of neovascular age-related macular degeneration (nAMD), 24 eyes of diabetic macular edema (DME), and 28 eyes of retinal vein occlusion (RVO). Aflibercept was used in 37 eyes and Ranibizumab was used in 40 eyes. 3 + PRN was used. Corneal endothelium and corneal thickness were measured using a corneal endothelial microscope. The data related to central corneal thickness, corneal endothelial cell density (ECD), average cell size, coefficient of variation (CV), proportion of hexagonal cells (Hex%) was collected. A comparison was also made between baseline and the dynamic changes of all indexes 1 year following the last injection. It was observed that in comparison to baseline, ECD and Hex% decreased significantly after the 3rd injection of Aflibercept and Ranibizumab. However, ECD did not decrease further and remained at the same level as after the last injection. Hex% and average cell size increased to a certain extent in comparison to the last injection. All the changes were found to be statistically significant (P < .01). After 3 injections, ECD in DME group was markedly lower than that in nAMD and RVO group, but the CV in DME group was higher than that in nAMD as well as RVO groups, and all the differences were statistically significant (P < .05). Following intravitreal anti-VEGF therapy, DME is more likely than other disorders to result in a decrease in ECD. Repeated intravitreal injections of anti-VEGF drugs can reduce the Hex% and ECD to a certain extent. After the last injection, Hex% can progressively recover, and ECD can remain stable without further declining. After injections, ECD in DME group was found to be significantly lower than that in nAMD and RVO groups, but CV in DME group was significantly higher in comparison to the other 2 groups. In patients with macular edema, repeated intravitreal injections of anti-VEGF may have certain effects on corneal morphology. Patients with diabetes mellitus in particular should pay special attention to corneal safety following repeated intravitreal injections if they have significantly reduced ECD at baseline.

Development of ARPE-19-Equipped Ocular Cell Model for In Vitro Investigation on Ophthalmic Formulations

Repeated intravitreal (IVT) injections in the treatment of retinal diseases can lead to severe complications. Developing innovative drug delivery systems for IVT administration is crucial to prevent adverse reactions, but requires extensive investigation including the use of different preclinical models (in vitro, ex vivo and in vivo). Our previous work described an in vitro tricompartmental ocular flow cell (TOFC) simulating the anterior and posterior cavities of the human eye. Based on promising preliminary results, in this study, a collagen scaffold enriched with human retinal pigmented epithelial cells (ARPE-19) was developed and introduced into the TOFC to partially mimic the human retina. Cells were cultured under dynamic flow conditions to emulate the posterior segment of the human eye. Bevacizumab was then injected into the central compartment of the TOFC to treat ARPE-19 cells and assess its effects. The results showed an absence of cytotoxic activity and a significant reduction in VEGF fluorescent signal, underscoring the potential of this in vitro model as a platform for researching new ophthalmic formulations addressing the posterior eye segment, eventually decreasing the need for animal testing.

An Update on Novel Ocular Nanosystems with Possible Benefits in the Treatment of Corneal Neovascularization

Corneal neovascularization (CNV) is an ocular pathological change that results from an imbalance between angiogenic factors and antiangiogenic factors as a result of various ocular insults, including infection, inflammation, hypoxia, trauma, corneal degeneration, and corneal transplantation. Current clinical strategies for the treatment of CNV include pharmacological treatment and surgical intervention. Despite some degree of success, the current treatment strategies are restricted by limited efficacy, adverse effects, and a short duration of action. Recently, gene-based antiangiogenic therapy has become an emerging strategy that has attracted considerable interest. However, potential complications with the use of viral vectors, such as potential genotoxicity resulting from long-term expression and nonspecific targeting, cannot be ignored. The use of ocular nanosystems (ONS) based on nanotechnology has emerged as a great advantage in ocular disease treatment during the last two decades. The potential functions of ONS range from nanocarriers, which deliver drugs and genes to target sites in the eye, to therapeutic agents themselves. Various preclinical studies conducted to date have demonstrated promising results of the use of ONS in the treatment of CNV. In this review, we provide an overview of CNV and its current therapeutic strategies and summarize the properties and applications of various ONS related to the treatment of CNV reported to date. Our goal is to provide a comprehensive review of these considerable advances in ONS in the field of CNV therapy over the past two decades to fill the gaps in previous related reports. Finally, we discuss existing challenges and future perspectives of the use of ONS in CNV therapy, with the goal of providing a theoretical contribution to facilitate future practical growth in the area.

Pharmacokinetics and Safety of an Intravitreal Humanized Anti-VEGF-A Monoclonal Antibody (PRO-169), a Biosimilar Candidate to Bevacizumab

Background

PRO-169 is a biosimilar candidate to bevacizumab (BEV), a monoclonal antibody (mAb) that inhibits vascular endothelial growth factor-A (VEGF-A) developed for intravitreal use. The current study demonstrates the intraocular pharmacokinetics (PK) of PRO-169 and its safety using New Zealand white (NZW) rabbits.

Methods

Intraocular concentration was evaluated in thirty-six rabbits at 1h, 1, 2, 5, 14 and 30 days after a single bilateral injection of PRO-169 or BEV (1.25 mg/0.05 mL). In a secondary experiment, safety was evaluated after three consecutive unilateral injections at 30-day intervals in twenty-four rabbits (PRO-169: 1.25 mg/0.05 mL or ranibizumab [RZB]: 0.5 mg/0.05 mL), by liver-associated enzymes (LAE), ophthalmological examination and adverse event (AE) incidence. Primary endpoints were vitreous maximum concentration (C_max), time to attain maximum concentration (t_max), area under curve (AUC_0-t), half-life (t_1/2) and LAE. Secondary endpoints included aqueous humor (AH) and plasma pharmacokinetics, clinical examination and AEs.

Results

The C_max in the vitreous was 593.75 ± 45.63 (PRO-169) vs 644.79 ± 62.65 µg/mL (BEV) (p= 0.136). T_max was 0.53 ± 0.82 vs 0.85 ± 0.73 days (p= 0.330). The AUC_0-t was 3837.72 ± 465.91 vs 4247.31 ± 93.99 days*µg/mL (p= 0.052) and the half-life was 4.99 ± 0.89 vs 5.18 ± 0.88 days (p= 0.711). LAEs were normal in 92% of NZW rabbits; no differences between groups were observed (p>0.05). The AH and plasma PKs were also similar. Finally, clinical examinations found no alterations. AEs were observed in 25% of PRO-169 rabbits, without differences vs RZB (p=0.399).

Conclusion

PRO-169 can be efficiently diffused and distributed in ocular compartments, showing vitreous pharmacokinetics analogous to BEV. The safety experiment did not find evidence of clinical alterations from a repeated injection of PRO-169. These results provide scientific justification supporting that PRO-169 should be evaluated in future clinical trials to confirm its safety and efficacy.

Effect of Topical Instillation of Pegaptanib Sodium Upon Inflammatory Corneal Neovascularization in Rabbits

Purpose: To evaluate the effect of topical instillation of pegaptanib sodium upon inflammatory angiogenesis induced in the rabbit cornea by alkaline cauterization. Methods: Inflammatory angiogenesis was induced by alkaline (sodium hydroxide) cauterization in the corneas of 29 male New Zealand rabbits. The animals were divided into 4 groups: a control group treated with 0.5% carboxymethylcellulose sodium eye drops, a group treated with 1.0% prednisolone acetate eye drops, a group treated with 0.5% pegaptanib sodium diluted in 15 mL 0.5% carboxymethylcellulose sodium, and a group treated with 1.0% pegaptanib sodium diluted in 15 mL 0.5% carboxymethylcellulose sodium. After cauterization, eye drops were administered every 12 hours for 21 days. The animals were evaluated every 3 days after cauterization, and the newly formed vessels were quantified from photographs. The treatment effectiveness was analyzed with 3 parameters of antiangiogenic response: neovascularization area (NA), total vascular length (TVL), and number of blood vessels (BVN). Results: Average NA, TVL, and BVN values were significantly higher in both pegaptanib groups than in the prednisolone group. A nonstatistically significant reduction in parameters on days 18 and 21 was the minimum achieved in both pegaptanib groups. The efficacy of the treatments in relation to the control was significantly greater in the prednisolone group than in the 0.5% pegaptanib group or the 1.0% pegaptanib group (P < 0.001). Conclusion: Topical instillation of 0.5% and 1.0% pegaptanib sodium diluted in 15 mL 0.5% carboxymethylcellulose sodium had no inhibitory effect on corneal neovascularization in this rabbit model.

Effect of Repeated Intravitreal Ranibizumab and Aflibercept Injections on the Cornea in Patients with Age-Related Macular Degeneration

Purpose

To assess the effect of repeated intravitreal ranibizumab injections (RI) and aflibercept injections (AI) on the corneal endothelium and central corneal thickness (CCT) in patients with age-related macular degeneration (AMD).

Materials and Methods

In the retrospective study, 110 eyes of 106 patients, aged 52 to 93 years, were analyzed. Fifty eyes were treated only with RI (I group), and 60 eyes were treated only with AI (II group). Every patient received one intravitreal injection of 0.5 mg of ranibizumab once a month or 2 mg of aflibercept for 3 subsequent months. Each patient received only 3 injections during the whole observation period. Corneal analysis was obtained with the specular microscope. Examinations were performed before initial treatment, after each injection, and 6 months after the first injection. Analysis included corneal endothelial cell density (ECD), hexagonal cell percentage (% Hex), coefficient of variation (CoV), and CCT.

Results

There was a statistically significant ECD loss, regardless of the type of the anti-VEGF agent. The mean ECD value in the I group was 2397 ± 459 cells/mm² before RI, 2389 ± 459 cells/mm² after the first RI, 2386 ± 467 cells/mm² after the second RI, 2378 ± 475 cells/mm² after the third RI, and 2357 ± 460 cells/mm² 6 months after the first RI. The mean ECD value in the II group was 2448 ± 493 cells/mm² before treatment, 2456 ± 498 cells/mm² after the first AI, 2426 ± 496 cells/mm² after the second AI, 2402 ± 488 cells/mm² after the third AI, and 2348 ± 473 cells/mm² 6 months after the first AI. In comparison with the group treated with RI, the group treated with AI presented a greater ECD loss at each measuring point. The percentage of hexagonal cells was decreased in both groups. There was a slight increase in polymegathism in both treated groups. Ranibizumab proved to cause a small increase in CCT, while CCT remained unchanged in the aflibercept group.

Conclusions

Repeated intravitreal injections of 0.5 mg of ranibizumab or 2 mg of aflibercept can influence the morphology of the corneal endothelium but not CCT.

Rosiglitazone accelerates wound healing by improving endothelial precursor cell function and angiogenesis in db/db mice

Background & Aims

Endothelial precursor cell (EPC) dysfunction is one of the risk factors for diabetes mellitus (DM) which results in delayed wound healing. Rosiglitazone (RSG) is a frequently prescribed oral glucose-lowering drug. Previous studies have shown the positive effects of RSG on ameliorating EPC dysfunction in diabetic patients. Interestingly, knowledge about RSG with regard to the wound healing process caused by DM is scarce. Therefore, in this study, we investigated the possible actions of RSG on wound healing and the related mechanisms involved in db/db diabetic mice.

Methods

Db/db mice with spontaneous glucose metabolic disorder were used as a type 2 DM model. RSG (20 mg/kg/d, i.g.,) was administered for 4 weeks before wound creation and bone marrow derived EPC (BM-EPC) isolation. Wound closure was assessed by wound area and CD31 staining. Tubule formation and migration assays were used to judge the function of the BM-EPCs. The level of vascular endothelial growth factor (VEGF), stromal cell derived factor-1α (SDF-1α) and insulin signaling was determined by ELISA. Cell viability of the BM-EPCs was measured by CCK-8 assay.

Results

RSG significantly accelerated wound healing and improved angiogenesis in db/db mice. Bioactivities of tube formation and migration were decreased in db/db mice but were elevated by RSG. Level of both VEGF and SDF-1α was increased by RSG in the BM-EPCs of db/db mice. Insulin signaling was elevated by RSG reflected in the phosphorylated-to-total AKT in the BM-EPCs. In vitro, RSG improved impaired cell viability and tube formation of BM-EPCs induced by high glucose, but this was prevented by the VEGF inhibitor avastin.

Conclusion

Our data demonstrates that RSG has benefits for wound healing and angiogenesis in diabetic mice, and was partially associated with improvement of EPC function through activation of VEGF and stimulation of SDF-1α in db/db mice.