Update on Retinal Drug Toxicities

In-vitro safety assessment of meropenem on human retinal pigment epithelium (RPE)

Purpose

Endophthalmitis is a severe infection accompanied by inflammation that affects the anterior and posterior parts of the eye. It is typically treated with a combination of antibiotics that cover various microorganisms. However, retinal pigment epithelium (RPE) cells are highly susceptible to damage from intravitreal injection therapy. This study aimed to investigate the impact of clinically relevant concentrations of meropenem (alone or in combination with vancomycin) on the viability and inflammation of RPE cells.

Design

In-vitro Study.

Methods

RPE cells from passages 5-7 were treated with different concentrations of meropenem (1/4x, x, and 4x; [x = 16 mg/L]), vancomycin (30 mg/L), and meropenem (x) plus vancomycin for 24 h. The morphology assessment and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay were performed to evaluate cytotoxicity due to drug treatment. Real-time PCR was used to measure the relative expression of apoptotic genes (BCL-2 and BAX) and inflammation biomarkers (IL-1b and IL-6).

Results

Meropenem (alone or in combination with vancomycin) did not have any significant effect on RPE cell morphology, density, and viability. Gene expression analysis confirmed these results, showing no significant changes in the BCL-2/BAX ratio in drug-treated RPE cells compared to controls. Treatment with meropenem significantly induced the expression of IL-1b at all studied concentrations. Additionally, at concentrations of x and 4x, it also significantly increased the expression of IL-6, which was dose-dependent. However, this effect was not observed with vancomycin alone or in combination with meropenem.

Conclusions

The results of this study suggest that meropenem, either alone or in combination with vancomycin, does not induce RPE cytotoxicity. There was an upregulation of IL-1b and IL-6 in meropenem monotherapy, the clinical implication of which should be elucidated in future in-vivo or clinical studies.

An Atypical Case of Severe Toxicity, Anterior Chamber Inflammation, and Transient Subretinal Fluid Formation Induced by the Subconjunctival Injection of 5-FU

PURPOSE

To report an atypical presentation of severe toxicity, anterior chamber (AC) inflammation, and transient parafoveal formation of subretinal fluid induced by the subconjunctival injection of 5-fluorouracil (5-FU).

METHODS

Case presentation.

RESULTS

Seven weeks after trabeculectomy, a 40-year-old white male had a subconjunctival injection of 5-FU. Within minutes after the injection, the lens turned grey and then total white. Initially, AC was clear, and 20 min later, a severe AC reaction was detected. The patient was prescribed hourly dexamethasone eye drops and tropicamide eye drops twice daily. Two days post-injection, vision improved, AC reaction was minimal, and there was whitish fibrinous material on the anterior surface of the lens, extending up to the pupillary margin. Minimal posterior synechiae were observed, and upon dilation, the remainder of the anterior surface of the lens appeared completely clear, indicating that only the portion of the lens not covered by the iris exhibited fibrinous material and deposits. One week post-injection, vision worsened due to severe corneal toxicity. The dimensions of the whitish fibrinous material on the anterior lens capsule decreased, and macular scans revealed parafoveal subretinal fluid. Two weeks later, vision significantly improved, and the dimensions of the whitish fibrinous material on the anterior lens capsule were further decreased. The subretinal fluid had completely resolved.

CONCLUSION

We describe a rare case of severe toxicity, AC inflammation, and transient parafoveal subretinal fluid formation caused by the 5-FU. This was treated with topical steroid treatment, and eventually some level of lens opacification persisted despite significant clearance of the AC inflammation.

Safety Profile and Adverse Event Management for Futibatinib, An Irreversible FGFR1-4 Inhibitor: Pooled Safety Analysis of 469 Patients

PURPOSE

Futibatinib, a covalently-binding inhibitor of fibroblast growth factor receptor (FGFR)1-4 gained approval for the treatment of refractory, advanced intrahepatic cholangiocarcinoma (iCCA) harboring an FGFR2 fusion/other rearrangement. An integrated analysis was performed to evaluate safety and provide guidance on the management of futibatinib-associated adverse events (AEs) in patients with unresectable/metastatic tumors, including iCCA.

PATIENTS AND METHODS

Data from three global phase I or II studies of futibatinib (NCT02052778; JapicCTI-142552) were pooled. AEs were graded per NCI CTCAE v4.03, where applicable. Safety was analyzed for patients receiving any futibatinib starting dose (overall population) and in those receiving the approved starting dose of 20 mg once every day.

RESULTS

In total, 469 patients with one of 33 known tumor types were analyzed, including 318 patients who received futibatinib 20 mg every day. AEs of clinical interest (AECI; any grade/grade ≥3) in the overall population included hyperphosphatemia (82%/19%), nail disorders (27%/1%), hepatic AEs (27%/11%), stomatitis (19%/3%), palmar-plantar erythrodysesthesia syndrome (PPES; 13%/3%), rash (9%/0%), retinal disorders (8%/0%), and cataract (4%/1%). Median time to onset of grade ≥3 AECIs ranged from 9 days (hyperphosphatemia) to 125 days (cataract). Grade ≥3 hyperphosphatemia, hepatic AEs, PPES, and nail disorders resolved to grade ≤2 within a median of 7, 7, 8, and 28 days, respectively. Discontinuations due to treatment-related AEs were rare (2%), and no treatment-related deaths occurred. AE management included phosphate-lowering medication and dose adjustments.

CONCLUSIONS

Futibatinib showed a consistent and manageable safety profile across patients with various tumor types. AECIs were mostly reversible with appropriate clinical management.

Recent advances in the use of optical coherence tomography in neuro-ophthalmology: A review

Optical coherence tomography (OCT) is an in vivo imaging modality that provides non-invasive, high resolution and fast cross-sectional images of the optic nerve head, retina and choroid. OCT angiography (OCTA) is an emerging tool. It is a non-invasive, dye-free imaging approach of visualising the microvasculature of the retina and choroid by employing motion contrast imaging for blood flow detection and is gradually receiving attention for its potential roles in various neuro-ophthalmic and retinal conditions. We will review the clinical utility of the OCT in the management of various common neuro-ophthalmic and neurological disorders. We also review some of the OCTA research findings in these conditions. Finally, we will discuss the limitations of OCT as well as introduce other emerging technologies.

Exploring the Spectrum of VEGF Inhibitors' Toxicities from Systemic to Intra-Vitreal Usage in Medical Practice

The use of Vascular Endothelial Growth Factor inhibitors (VEGFi) has become prevalent in the field of medicine, given the high incidence of various pathological conditions necessitating VEGF inhibition within the general population. These conditions encompass a range of advanced neoplasms, such as colorectal cancer, non-small cell lung cancer, renal cancer, ovarian cancer, and others, along with ocular diseases. The utilization of VEGFi is not without potential risks and adverse effects, requiring healthcare providers to be well-prepared for identification and management. VEGFi can be broadly categorized into two groups: antibodies or chimeric proteins that specifically target VEGF (bevacizumab, ramucirumab, aflibercept, ranibizumab, and brolucizumab) and non-selective and selective small molecules (sunitinib, sorafenib, cabozantinib, lenvatinib, regorafenib, etc.) designed to impede intracellular signaling of the VEGF receptor (RTKi, receptor tyrosine kinase inhibitors). The presentation and mechanisms of adverse effects resulting from VEGFi depend primarily on this distinction and the route of drug administration (systemic or intra-vitreal). This review provides a thorough examination of the causes, recognition, management, and preventive strategies for VEGFi toxicities with the goal of offering support to oncologists in both clinical practice and the design of clinical trials.

A novel ocular phenotype associated with pathogenic variants in MFSD8 leading to macular dystrophy

BACKGROUND

The major facilitator superfamily domain-containing protein 8 (MFSD8) pathogenic variants are classically associated with autosomal recessive neuronal ceroid lipofuscinosis-7. Case reports have recently demonstrated an association of MFSD8 variants causing autosomal recessive macular dystrophy with central cone involvement without neurologic sequelae. We report a patient with a novel ocular phenotype associated with MFSD8 pathogenic variants causing macular dystrophy without systemic findings.

CASE PRESENTATION

A 37-year-old female presented with a 20-year history of progressive bilateral vision loss. Fundus examination was notable for a slight pigmentary ring around the fovea in both eyes. Optical coherence tomography (OCT) of the macula showed bilateral subfoveal ellipsoid zone loss without outer retinal changes. Fundus autofluorescence (FAF) demonstrated foveal hypo-autofluorescence (AF) in both eyes as well as hyper-AF nasally to the optic nerve in the perifoveal area. Full-field and multifocal electroretinography demonstrated cone dysfunction with diffuse macular changes in both eyes. Subsequent genetic testing identified two pathogenic MFSD8 variants. The patient had no neurologic symptoms consistent with variant-late infantile neuronal ceroid lipofuscinosis.

CONCLUSION

MFSD8 pathogenic variants are known to cause macular dystrophies. We report a novel MFSD8-associated macular dystrophy phenotype demonstrating foveal-limited disease with cavitary changes on OCT without inner retinal atrophy and foveal-specific changes on FAF. A threshold model can explain how a hypomorphic missense variant heterozygous with a loss-of-function nonsense variant can lead to a predominantly ocular phenotype with preserved neurologic function. We recommend careful monitoring of these patients for future signs of both retinal and systemic disease progression.

Curcumin attenuates hydroxychloroquine-mediated apoptosis and oxidative stress via the inhibition of TRPM2 channel signalling pathways in a retinal pigment epithelium cell line

PURPOSE

Hydroxychloroquine (HCQ) is used in the treatment of several diseases, such as malaria, Sjögren's disease, Covid-19, and rheumatoid arthritis. However, HCQ induces retinal pigment epithelium death via the excessive increase of cytosolic (cROS) and mitochondrial (mROS) free oxygen radical production. The transient receptor potential melastatin 2 (TRPM2) cation channel is stimulated by ADP-ribose (ADPR), cROS, and mROS, although it is inhibited by curcumin (CRC). We aimed to investigate the modulating action of CRC on HCQ-induced TRPM2 stimulation, cROS, mROS, apoptosis, and death in an adult retinal pigment epithelial 19 (ARPE19) cell line model.

MATERIAL AND METHODS

ARPE19 cells were divided into four groups: control (CNT), CRC (5 µM for 24 h), HCQ (60 µM for 48 h), and CRC + HCQ groups.

RESULTS

The levels of cell death (propidium iodide positive cell numbers), apoptosis markers (caspases -3, -8, and -9), oxidative stress (cROS and mROS), mitochondria membrane depolarization, TRPM2 current density, and intracellular free Ca2+ and Zn2+ fluorescence intensity were upregulated in the HCQ group after stimulation with hydrogen peroxide and ADPR, but their levels were downregulated by treatments with CRC and TRPM2 blockers (ACA and carvacrol). The HCQ-induced decrease in retinal live cell count and cell viability was counteracted by treatment with CRC.

CONCLUSION

HCQ-mediated overload Ca2+ influx and retinal oxidative toxicity were induced in an ARPE19 cell line through the stimulation of TRPM2, although they were attenuated by treatment with CRC. Hence, CRC may be a potential therapeutic antioxidant for TRPM2 activation and HCQ treatment-induced retinal oxidative injury and apoptosis.

Retinal organoids in disease modeling and drug discovery: Opportunities and challenges

Diseases leading to retinal cell loss can cause severe visual impairment and blindness. The lack of effective therapies to address retinal cell loss and the absence of intrinsic regeneration in the human retina leads to an irreversible pathological condition. Progress in recent years in the generation of human three-dimensional retinal organoids from pluripotent stem cells makes it possible to recreate the cytoarchitecture and associated cell-cell interactions of the human retina in remarkable detail. These human three-dimensional retinal organoid systems made of distinct retinal cell types and possessing contextual physiological responses allow the study of human retina development and retinal disease pathology in a way animal model and two-dimensional cell cultures were unable to achieve. We describe the derivation of retinal organoids from human pluripotent stem cells and their application for modeling retinal disease pathologies, while outlining the opportunities and challenges for its application in academia and industry.

Trends and practices following the 2016 hydroxychloroquine screening guidelines

This study aimed to understand the profile of hydroxychloroquine-treated patients, referral patterns, and dosing and to assess the adherence of eye care providers to the latest 2016 screening guidelines provided by the American Academy of Ophthalmology. Patients were identified using electronic health records (EHR) taking hydroxychloroquine and were seen by optometrists, retinal specialists, and non-retinal ophthalmologists. Review of EHR data includes demographic characteristics, indications, and dosing profile of hydroxychloroquine use, eye care provider managing the patient, and imaging modalities performed. A total of 166 patients were included in the study. The most common indications for screening were systemic lupus erythematosus and discoid lupus (52.4%) followed by rheumatoid arthritis (18.7%) and Sjögren's syndrome (9.6%). Ninety-two (55.4%) patients were on a higher-than-recommended dose of > 5 mg/kg/day. Patients who weighed less (mean 63.9 kg) were taking a higher-than-recommended dose (vs. 81.5 kg, p < 0.001). Although retinal specialists adhered best to the use of all three recommended imaging modalities, visual field testing was done appropriately for only 8.3% of Asian and 71.1% of non-Asian patients. In conclusion, there is substantial variability in screening by ophthalmic providers and prescribing practices compared with the current recommendations. In particular, there is a marked deficiency in correct visual field testing in Asian patients. These findings are important to highlight potential interventions to improve screening for hydroxychloroquine toxicity.

PENTOSAN POLYSULFATE SODIUM (ELMIRON) MACULOPATHY: A Genetic Perspective

PURPOSE

To assess genetic associations for pentosan polysufate sodium maculopathy.

METHODS

Genetic testing for inherited retinal dystrophy genes using exome testing and for 14 age-related macular degeneration-associated single nucleotide polymorphisms (SNPs) using panel testing were performed. In addition, full-field electroretinograms (ffERG) were obtained to identify any cone-rod dystrophy.

RESULTS

Eleven of 15 patients were women, with a mean age of 69 (range 46-85). Inherited retinal dystrophy exome testing in five patients revealed six pathogenic variants, but failed to confirm inherited retinal dystrophy in any patient genetically. FfERG performed in 12 patients demonstrated only nonspecific a- and b-wave abnormalities in 11 cases and was normal in one case. For age-related macular degeneration single nucleotide polymorphisms, CFH rs3766405 ( P = 0.003) and CETP ( P = 0.027) were found to be statistically significantly associated with pentosan polysulfate maculopathy phenotype compared with the control population.

CONCLUSION

Pentosan polysulfate maculopathy is not associated with Mendelian inherited retinal dystrophy genes. However, several age-related macular degeneration risk alleles were identified to be associated with maculopathy compared with their frequency in the normal population. This suggests a role for genes in disease pathology, particularly the alternative complement pathway. These findings would benefit from further investigation to understand the risk of developing maculopathy in taking pentosan polysulfate.

How to Set Up Genetic Counselling for Inherited Macular Dystrophies: Focus on Genetic Characterization

Inherited macular dystrophies refer to a group of degenerative conditions that predominantly affect the macula in the spectrum of inherited retinal dystrophies. Recent trends indicate a clear need for genetic assessment services in tertiary referral hospitals. However, establishing such a service can be a complex task due to the diverse skills required and multiple professionals involved. This review aims to provide comprehensive guidelines to enhance the genetic characterization of patients and improve counselling efficacy by combining updated literature with our own experiences. Through this review, we hope to contribute to the establishment of state-of-the-art genetic counselling services for inherited macular dystrophies.

[Exogenously induced retinopathies]

Exogenously induced retinopathies can be caused by consumation of stimulating substances, systemic or ocular medications, vaccinations, light or irradiation. Some of the effects are transient, whereas other effects induce irreversible toxic reactions. Retinal damage may develop either acutely with obvious relation to the damaging cause, but often may take a long duration of repeated use of a substance or medication. External stimulants (e.g. nicotine, alcohol, poppers, methanol) are the most frequent cause of exogenously induced retinal damage. Side effects from systemic drugs (e.g. hydroxychloroquine, ethambutol, MEK-, ERK-, FLT3-, checkpoint inhibitors, didanosin, pentosanpolysulfat sodium) or intravitreally applied drugs (e.g. antibiotics, VEGF-inhibitors) are less frequent. Ocular side effects associated with vaccinations are rare. Ambient light sources induce no damaging effects on the retina. Incorrect use of technical or medical light sources (e.g. laser pointers) without adherence to safety recommendations or unshielded observation of the sun might induce permanent retinal damage. Local or external irradiation might induce retinal vascular damage resulting in radiation retinopathy.

Exogen bedingte Retinopathien

Exogen bedingte Retinopathien werden am häufigsten durch externe Stimulanzien, seltener durch unerwünschte Arzneimittelwirkungen systemisch oder intravitreal eingesetzter Medikamente und noch seltener durch Impfungen oder die Einwirkung von Lichtstrahlung verursacht. Die Kenntnis exogener Ursachen und ihre mögliche Symptomatik ist zur Prophylaxe oder zur Früherkennung schädigender Wirkungen und zur adäquaten Beratung der Patienten wichtig.