Melanocortin 5 Receptor Expression and Recovery of Ocular Immune Privilege after Uveitis

Immunopeptides: immunomodulatory strategies and prospects for ocular immunity applications

Immunopeptides have low toxicity, low immunogenicity and targeting, and broad application prospects in drug delivery and assembly, which are diverse in application strategies and drug combinations. Immunopeptides are particularly important for regulating ocular immune homeostasis, as the eye is an immune-privileged organ. Immunopeptides have advantages in adaptive immunity and innate immunity, treating eye immune-related diseases by regulating T cells, B cells, immune checkpoints, and cytokines. This article summarizes the application strategies of immunopeptides in innate immunity and adaptive immunity, including autoimmunity, infection, vaccine strategies, and tumors. Furthermore, it focuses on the mechanisms of immunopeptides in mediating ocular immunity (autoimmune diseases, inflammatory storms, and tumors). Moreover, it reviews immunopeptides' application strategies and the therapeutic potential of immunopeptides in the eye. We expect the immune peptide to get attention in treating eye diseases and to provide a direction for eye disease immune peptide research.

Efficacy and Safety of the Melanocortin Pan-Agonist PL9643 in a Phase 2 Study of Patients with Dry Eye Disease

Purpose: The melanocortin receptor pan-agonist PL9643, a potential therapy for ocular diseases, was investigated in a phase 2, 12-week study in patients with dry eye disease (DED). Methods: This was a placebo-controlled study evaluating efficacy and safety of thrice-daily PL9643. Placebo (vehicle) was similar to tears. Primary endpoints were intra-patient changes in inferior corneal fluorescein staining and ocular discomfort after 12 weeks. Secondary endpoints were changes in additional DED signs or symptoms. Multiple secondary endpoints were not adjusted for multiplicity. Patients with moderate or severe DED were analyzed in addition to the overall intent-to-treat (ITT) population. Results: In the ITT population (n = 160) the PL9643 group did not demonstrate significant treatment difference versus placebo at week 12/day 85 for the primary endpoints (P > 0.05). In patients with moderate or severe DED (n = 53), PL9643 treatment demonstrated either nominally significant (P < 0.05) or trending (P < 0.1) improvement over placebo in mean change from baseline at week 12/day 85 in several sign endpoints, including fluorescein staining in inferior, superior, corneal sum, and total sum regions; Lissamine Green staining in temporal, nasal, conjunctival sum, and total sum regions; and tear film breakup time. Conjunctival redness also showed (nonsignificant) improvement at week 12/day 85. There were no drug-related adverse events (AEs) and no drug-related discontinuations. Conclusions: PL9643 showed no significant efficacy for the ITT population; however, efficacy results across several signs and symptoms in the subpopulation of moderate to severe DED patients, the low number of ocular AEs, and no tolerability issues suggest that PL9643 shows promise as a therapeutic for DED. Clinical Trial Registration number: NCT04268069.

Melanocortin/MC5R axis regulates the proliferation of hematopoietic stem cells in mice after ionizing radiation injury

Hematopoietic stem cells (HSCs) possess great self-renewal and multidirectional differentiation abilities, which contribute to the continuous generation of various blood cells. Although many intrinsic and extrinsic factors have been found to maintain HSC homeostasis, the precise regulation of hematopoiesis under stress conditions is poorly understood. In this study, we show that melanocortin receptor 5 (MC5R) is abundantly expressed in hematopoietic stem progenitor cells (HSPCs). Using an MC5R knockout mouse model, we observed that it is not essential for steady-state hematopoiesis. Interestingly, the levels of α-melanocyte stimulating hormone (α-MSH), an important subtype of melanocortin, were elevated in the serum and bone marrow, and the expression of MC5R was upregulated in HSPCs from mice after irradiation. MC5R deficiency aggravates irradiation-induced myelosuppression because of impaired proliferation and reconstitution of HSCs. Further investigation revealed that the melanocortin/MC5R axis regulates the proliferation of HSCs by activating the PI3K/AKT and MAPK pathways. More importantly, α-MSH treatment can significantly accelerate hematopoietic recovery in irradiated mice. In conclusion, our data demonstrate that the melanocortin/MC5R axis plays a crucial role in regulating HSC proliferation under stress, thus providing a promising strategy to promote hematopoietic regeneration when suffering from injury.

The multifunctional human ocular melanocortin system

Immune privilege in the eye involves physical barriers, immune regulation and secreted proteins that together limit the damaging effects of intraocular immune responses and inflammation. The neuropeptide alpha-melanocyte stimulating hormone (α-MSH) normally circulates in the aqueous humour of the anterior chamber and the vitreous fluid, secreted by iris and ciliary epithelium, and retinal pigment epithelium (RPE). α-MSH plays an important role in maintaining ocular immune privilege by helping the development of suppressor immune cells and by activating regulatory T-cells. α-MSH functions by binding to and activating melanocortin receptors (MC1R to MC5R) and receptor accessory proteins (MRAPs) that work in concert with antagonists, otherwise known as the melanocortin system. As well as controlling immune responses and inflammation, a broad range of biological functions is increasingly recognised to be orchestrated by the melanocortin system within ocular tissues. This includes maintaining corneal transparency and immune privilege by limiting corneal (lymph)angiogenesis, sustaining corneal epithelial integrity, protecting corneal endothelium and potentially enhancing corneal graft survival, regulating aqueous tear secretion with implications for dry eye disease, facilitating retinal homeostasis via maintaining blood-retinal barriers, providing neuroprotection in the retina, and controlling abnormal new vessel growth in the choroid and retina. The role of melanocortin signalling in uveal melanocyte melanogenesis however remains unclear compared to its established role in skin melanogenesis. The early application of a melanocortin agonist to downregulate systemic inflammation used adrenocorticotropic hormone (ACTH)-based repository cortisone injection (RCI), but adverse side effects including hypertension, edema, and weight gain, related to increased adrenal gland corticosteroid production, impacted clinical uptake. Compared to ACTH, melanocortin peptides that target MC1R, MC3R, MC4R and/or MC5R, but not adrenal gland MC2R, induce minimal corticosteroid production with fewer amdverse systemic effects. Pharmacological advances in synthesising MCR-specific targeted peptides provide further opportunities for treating ocular (and systemic) inflammatory diseases. Following from these observations and a renewed clinical and pharmacological interest in the diverse biological roles of the melanocortin system, this review highlights the physiological and disease-related involvement of this system within human eye tissues. We also review the emerging benefits and versatility of melanocortin receptor targeted peptides as non-steroidal alternatives for inflammatory eye diseases such as non-infectious uveitis and dry eye disease, and translational applications in promoting ocular homeostasis, for example, in corneal transplantation and diabetic retinopathy.

Stimulating the Melanocortin System in Uveitis and Diabetes Preserves the Structure and Anti-Inflammatory Activity of the Retina

The endogenous neuropeptide α-Melanocyte Stimulating Hormone (α-MSH) is a potent suppressor of inflammation and has an essential role in maintaining the normal anti-inflammatory microenvironment of the retina. While the therapeutic use of α-MSH peptide in uveitis and diabetic retinopathy models has been demonstrated, its short half-life and instability limit its use as a therapeutic drug. A comparable analog, PL-8331, which has a stronger affinity to melanocortin receptors, longer half-life, and, so far, is functionally identical to α-MSH, has the potential to deliver melanocortin-based therapy. We examined the effects of PL-8331 on two mouse models of retinal disease, Experimental Autoimmune Uveoretinitis (EAU) and Diabetic Retinopathy (DR). PL-8331 therapy applied to mice with EAU suppressed EAU and preserved retinal structures. In diabetic mice, PL-8331 enhanced the survival of retinal cells and suppressed VEGF production in the retina. In addition, retinal pigment epithelial cells (RPE) from PL-8331-treated diabetic mice retained normal anti-inflammatory activity. The results demonstrated that the pan-melanocortin receptor agonist PL-8331 is a potent therapeutic drug to suppress inflammation, prevent retinal degeneration, and preserve the normal anti-inflammatory activity of RPE.

Ocular immune privilege and retinal pigment epithelial cells

The ocular tissue microenvironment is immune-privileged and uses multiple immunosuppressive mechanisms to prevent the induction of inflammation. The retinal pigment epithelium plays an essential role in ocular immune privilege. In addition to serving as a blood barrier separating the fenestrated choriocapillaris from the retina, the retinal pigment epithelium is a source of immunosuppressive cytokines and membrane-bound negative regulators that modulate the activity of immune cells within the retina. This article reviews the current understanding of how retinal pigment epithelium cells mediate immune regulation, focusing on the changes under pathologic conditions.

A novel uveitis model induced by lipopolysaccharide in zebrafish

Objective

Endotoxin-induced uveitis (EIU) is an important tool for human uveitis study. This study was designed to develop a novel EIU model in zebrafish.

Methods

An EIU model in zebrafish was induced by intravitreal lipopolysaccharide (LPS) injection and was assessed dynamically. Optical coherence tomography (OCT) was used to assess infiltrating cells in the vitreous body. The histological changes wereevaluated using HE staining and immune cells were measured by immunofluorescence. The retinal RNA Sequencing (RNA-Seq) was used to explore the transcriptional changes during inflammation. RNA-Seq data were analyzed using time-course sequencing data analysis (TCseq), ClueGO plugin in Cytoscape, and Gene Set Enrichment Analysis (GSEA) software. Flow cytometry and retinal flat mounts were used to dynamically quantify the immune cells.

Results

EIU was successfully induced in zebrafish following intravitreal LPS injection. Inflammation appeared at 4 hours post injection (hpi), reached its peak at 24 hpi, and then resolved at 72 hpi. Immunofluorescence confirmed that massive influx ofneutrophils into the iris and vitreous body, and activation of microglia as evidenced by ameboid-shaped appearance in the retina. Retinal RNA-seq during the EIU course identified four gene clusters with distinct expression characteristics related to Toll-likereceptor signaling pathway, cytokine-cytokine receptor interaction, NOD-like receptor signaling pathway, and extracellular matrix (ECM)-receptor interaction, respectively. Prednisone immersion inhibited the inflammatory response of EIU in zebrafish, whichwas confirmed by decreased neutrophils detected in flow cytometry and retinal flat mounts.

Conclusions

We developed a novel EIU model in zebrafish, which may be particularly useful for gene-editing and high-throughput screening of new drugs for the prevention and treatment of uveitis.

A Novel Development of Sarcoidosis Following COVID-19 Vaccination and a Literature Review

BNT162b2 (Pfizer/BioNTech) is a coronavirus disease 2019 (COVID-19) vaccine containing nucleoside-modified messenger RNA encoding the severe acute respiratory syndrome coronavirus 2 spike glycoprotein. Recently, ocular complications of mRNA vaccines have been reported increasingly frequently. However, immunological adverse events due to mRNA vaccines in real-world settings are not fully known. We herein report the novel development of sarcoidosis manifested as uveitis, bilateral hilar lymphadenopathy, angiotensin-converting enzyme elevation, and epithelioid and giant cell granuloma formation in the lung soon after the first BNT162b2 injection and review the current literature, including three reported cases of sarcoid-like reaction following COVID-19 vaccination.

Melanocortin-5 Receptor: Pharmacology and Its Regulation of Energy Metabolism

As the most recent melanocortin receptor (MCR) identified, melanocortin-5 receptor (MC5R) has unique tissue expression patterns, pharmacological properties, and physiological functions. Different from the other four MCR subtypes, MC5R is widely distributed in both the central nervous system and peripheral tissues and is associated with multiple functions. MC5R in sebaceous and preputial glands regulates lipid production and sexual behavior, respectively. MC5R expressed in immune cells is involved in immunomodulation. Among the five MCRs, MC5R is the predominant subtype expressed in skeletal muscle and white adipose tissue, tissues critical for energy metabolism. Activated MC5R triggers lipid mobilization in adipocytes and glucose uptake in skeletal muscle. Therefore, MC5R is a potential target for treating patients with obesity and diabetes mellitus. Melanocortin-2 receptor accessory proteins can modulate the cell surface expression, dimerization, and pharmacology of MC5R. This minireview summarizes the molecular and pharmacological properties of MC5R and highlights the progress made on MC5R in energy metabolism. We poInt. out knowledge gaps that need to be explored in the future.

Retinal vascular occlusion and SARS-CoV-2 vaccination

PURPOSE

To assess the clinical and retinal imaging features of patients in whom retinal vascular occlusion (VO) had developed in temporal associations with COVID-19 vaccination.

METHODS

In this retrospective case series, all consecutive adult patients with new onset VO within 6 weeks of vaccination against COVID-19 were included in the study between May 1 and October 31, 2021. All patients had a systemic medical health assessment, full ophthalmic evaluation, and complete fundus imaging.

RESULTS

Fifteen eyes of VO (14 patients) after COVID-19 vaccinations were identified. The median time between vaccination and symptoms onset was 14 days (range 7-42 days). The mean best-corrected visual acuity (BCVA) was 20/55 with a range of 20/20 to 20/200. Eleven of 15 eyes (73.3%) had visual acuity improvement after intravitreal treatment at 60-90 days (range, 45-105 days) from the presentation. Four of 5 cases without systemic risk factors for VO had a mean BCVA > 20/32 at presentation and > 20/25 at the latest evaluation. Between May 1 and October 31, 2021, a temporal association was found between the 15 reported cases and COVID-19 vaccination out of a total of 29 VO (p = 0.05). The incidence of VO was higher in the considered period compared to the equivalent 6-month period in 2019 (1.17% vs 0.52%, respectively; p = 0.0134).

CONCLUSIONS

Retinal vascular occlusion with different grades of severity are reported in temporal association with COVID-19 vaccination. The exact pathogenic mechanism needs to be further studied. No certain causal relationship can be established from this case series.

Non-arteritic Anterior Ischemic Optic Neuropathy with Macular Star following COVID-19 Vaccination

PURPOSE

To report a case of non-arteritic anterior ischemic optic neuropathy (NAAION) with macular star after receiving the second dose of SARS-CoV-2 vaccination.

METHOD

Case report.

OBSERVATION

A 51-year-old male presented with acute visual disturbances one day after the second dose of BNT162b2 mRNA SARS-CoV-2 vaccination. At presentation, best corrected visual acuity (BCVA) was 20/25 right eye (OD) and counting fingers at 3 feet left eye (OS). Anterior segment examination was normal in both eyes. Dilated fundoscopy was unremarkable OD, however, it disclosed optic nerve swelling and subretinal fluid OS. Patient was treated with a gradual tapering dose of oral prednisone over 1 month. At the five-week follow-up visit, optic disc swelling and subretinal fluid resolved with minimal improvement in BCVA to 20/400 OS.

CONCLUSION

It is unclear whether COVID-19 vaccination was the triggering agent to the NAAION or just a coincidence, yet ophthalmologists should be aware of such a possible association.

Manifestation of Herpetic Eye Disease after COVID-19 Vaccine: A UK Case Series

PURPOSE

To highlight the potential risk of herpetic eye disease (HED) reactivation following COVID-19 vaccine.

METHODS

Retrospective analysis of all patients who presented with HED within 28 days post-first dose COVID-19 vaccination.

RESULTS

Eleven eyes (n = 10 patients) were included. The mean interval between COVID-19 vaccination and ocular symptoms/signs was 12.3 ± 10.3 days. Four (40%) patients presented with HSV keratitis, and six (60%) patients presented with VZV keratitis (five had concurrent other signs of herpes zoster ophthalmicus). Common ocular signs included multiple scattered dendritic/pseudodendritic corneal epitheliopathy (90.9%), anterior uveitis (63.6%), and endothelitis (27.3%). All cases were successfully treated with topical and systemic antiviral treatment and/or topical corticosteroids (mean healing time = 3.9 ± 1.6 weeks).

CONCLUSIONS

Our case series highlights the potential temporal association between HED and COVID-19 vaccine. Prophylactic antiviral treatment is recommended in patients with a history of HED prior to COVID-19 vaccination.

Severe panuveitis with iridis rubeosis activation and cystoid macular edema after BioNTech-Pfizer COVID-19 vaccination in a 17-year-old

We report a case of severe uveitis flare-up with iridis rubeosis recurrence and cystoid macular edema early after the first BioNTech-Pfizer COVID-19 vaccination in a 17-year-old boy. We also performed a systematic literature review on ocular inflammation after COVID-19 vaccinations.

Bilateral Panuveitis with Occlusive Vasculitis following Coronavirus Disease 2019 Vaccination

PURPOSE

To report a case of bilateral panuveitis and occlusive vasculitis following COVID-19 vaccination.

STUDY DESIGN

Case report.

RESULTS

A 41-year-old otherwise healthy male presented with progressive vision loss and floaters starting 48 hours after a first dose of COVID-19 vaccine. Examination initially showed bilateral anterior uveitis, but this evolved into bilateral panuveitis with occlusive vasculitis despite topical corticosteroids over two weeks. The patient underwent extensive testing for other etiologies which were excluded. He was successfully treated with a gradual taper of topical and systemic corticosteroids leading to improvement of signs and symptoms. Follow-up is maintained for observation of avascular zones with possible neovascularization which could require laser as needed.

CONCLUSIONS

The temporal association between vaccine and presentation makes this a plausible etiology. This remains a rare adverse event, but clinicians should be aware of this possibility to include it in their differential diagnosis when confronted with idiosyncratic ocular presentations.

Posterior Scleritis Following COVID-19 Vaccination: A Case Report

PURPOSE

To report a case of posterior scleritis following COVID-19 vaccination.

STUDY DESIGN

Case report.

RESULTS

A 78-year-old female presented with headache and right-sided visual loss 10 days after the second dose of COVID-19 vaccine. 'Examination showed disc oedema and a serous retinal detachment. B-scan ultrasound showed thickening of the posterior sclera with retroscleral fluid. CT head with venogram excluded venous sinus thrombosis. The patient's condition improved rapidly with oral corticosteroids with restoration of vision and resolution of disc swelling and serous detachment by 4 weeks.

CONCLUSIONS

Posterior scleritis should be considered in patients presenting with headaches and blurred vision following vaccination. Timely diagnosis and treatment with corticosteroids can prevent permanent visual loss.

Peripheral Ulcerative Keratitis Secondary to the Inactive COVID-19 Vaccine-CoronaVac

PURPOSE

To report a case of peripheral ulcerative keratitis (PUK) secondary to the inactive Covid-19 vaccine.

METHODS

The case of a 67-year-old man who presented with unilateral progressive vision-threatening PUK with nodular scleritis was reported. The results of clinical examinations with surgical and medical treatments were noted.

RESULTS

The extended workup for autoimmune and infectious etiologies for PUK that all returned negative. The patient was treated with oral steroids, azathioprine, and topical cyclosporine with topical dexamethasone for his PUK and underlying possible immunopathology. Corneal amniotic membrane grafting was also performed 4 times and finally, the patient underwent penetrant keratoplasty for visual rehabilitation.

CONCLUSIONS

To our knowledge, we report the first case of PUK that is possible to secondary to an inactive vaccine for SARS-CoV-2. The inactive covid vaccine should be considered as an etiological agent in PUK cases where the standard workup is negative.

Multiple Evanescent White Dot Syndrome following COVID-19 mRNA Vaccination in Two Patients

PURPOSE

To describe two cases of multiple evanescent white dot syndrome (MEWDS) occurring after administration of COVID-19 vaccine.

STUDY DESIGN

Case Report.

RESULTS

Two patients presented soon after receiving their second-dose of the BNT162b2 Pfizer-BioNTech COVID-19 vaccine with findings consistent with MEWDS. Due to the significant reduction in vision, patients were treated with a short dose of oral corticosteroids. Both had complete resolution of their symptoms, visual acuity and retinal findings.

CONCLUSIONS

The onset of inflammatory ocular adverse events following COVID-19 vaccinations suggest a maladaptive inflammatory response triggered by the vaccine. Onset of symptoms after COVID-19 vaccinations should prompt the ophthalmologist to assess for these rare adverse events. Despite the extremely rare occurrences of ocular adverse events, we unequivocally recommend that patients receive the full vaccine due to the vast benefit for both individuals and society that far outweighs the inconsiderable risk of harm.

Third cranial nerve palsy in an 88-year-old man after SARS-CoV-2 mRNA vaccination: change of injection site and type of vaccine resulted in an uneventful second dose with humoral immune response

Vaccines for SARS-CoV-2 currently authorised by the European Medicine Agency are effective, safe and well tolerated in practice. Awareness of rare potential vaccine-related adverse effects (AEs) is important to improve their recognition, management and reporting. An 88-year-old man attended the emergency department with incomplete palsy of the right third cranial nerve 3 days after the first administration of Moderna mRNA-1273 SARS-CoV-2 vaccine. Imaging ruled out a vascular accident and a vaccine AE was hypothesised. Two weeks of oral steroids led to the patient's recovery, but without evidence of humoral immune response to vaccine. Thus, full immunisation with a dose of Pfizer mRNA-BNT162b2 SARS-CoV-2 vaccine in a different site was attempted. This was uneventful and followed by a robust antibody response. Empirical change of site and vaccine brand may represent a tailored option to obtain full immune protection in selected patients, after vaccine AEs.

Bilateral Panuveitis Mimicking Vogt-Koyanagi-Harada Disease following the First Dose of ChAdOx1 nCoV-19 Vaccine

METHOD

We report a case of bilateral panuveitis and its resolution based on multimodal retinal images after she was administered the first dose of a viral vector-based vaccine against SARS-CoV-2.

CASE REPORT

A 72-year-old woman complained of bilateral blurred vision with headache, neck stiffness, and tinnitus 3 days after receiving the first dose of the ChAdOx1 nCoV-19 vaccine. Initial examination revealed anterior chamber reactions, left optic disc hyperemia, and bilateral chorioretinal folds with choroidal thickening. Fluorescein and indocyanine green angiography revealed bilateral choroiditis and papillitis. Systemic steroid therapy dramatically alleviated panuveitis and meningeal signs. No recurrence was noted until 3 months after discontinuation of steroids.

CONCLUSIONS

Bilateral panuveitis mimicking Vogt-Koyanagi-Harada disease can develop shortly after the first dose of the ChAdOx1 nCoV-19 vaccine. Ophthalmologists should consider bilateral panuveitis as a presumed post-vaccination adverse event. Systemic steroid therapy may be effective for the nCoV-19 vaccine-associated panuveitis.

Retinal hemorrhage of late post-COVID-19 and post-vaccine-related pathogenic mechanisms: A new challenge for ophthalmologist in COVID era

COVID-19 infection results in extensive organ dysfunction. Thrombotic problems linked to COVID-19 disease are common and can affect the retina. We will report a case of retina hemorrhage with possibility of linkage between COVID-19 infection and immunization to determine whether these abnormalities are causal or coincidental.

Melanocortin receptor agonists suppress experimental autoimmune uveitis

The melanocortin system plays an essential role in the regulation of immune activity. The anti-inflammatory microenvironment of the eye is dependent on the expression of the melanocortin-neuropeptide alpha-melanocyte stimulating hormone (α-MSH). In addition, the melanocortin system may have a role in retinal development and retinal cell survival under conditions of retinal degeneration. We have found that treating experimental autoimmune uveitis (EAU) with α-MSH suppresses retinal inflammation. Also, this augmentation of the melanocortin system promotes immune tolerance and protection of the retinal structure. The benefit of α-MSH-therapy appears to be dependent on different melanocortin receptors. Therefore, we treated EAU mice with α-MSH-analogs with different melanocortin-receptor targets. This approach demonstrated which melanocortin-receptors suppress inflammation, preserve retinal structure, and induce immune tolerance in uveitis. At the chronic stage of EAU the mice were injected twice 1 day apart with 50 μg of α-MSH or an α-MSH-analog. The α-MSH-analogs were a pan-agonist PL8331, PL8177 (potent MC1r-only agonist), PL5000 (a pan-agonist with no MC5r functional activity), MT-II (same as PL5000) and PG901 (MC5r agonist, but also an antagonist to MC3r, and MC4r). Clinical EAU scores were measured until resolution in the α-MSH-treated mice, when the eyes were collected for histology, and spleen cells collected for retinal-antigen-stimulated cytokine production. Significant suppression of EAU was seen with α-MSH or PL8331 treatment. This was accompanied with significant preservation of retinal structure. A similar effect was seen in EAU-mice that were treated with PL8177, except the suppression of EAU was temporary. In EAU mice treated with PL5000, MTII, or PG901, there was no suppression of EAU with a significant loss in whole retina and outer-nuclear layer thickness. There was significant suppression of IL-17 with induction of IL-10 by retinal-antigen stimulated spleen T cells from EAU mice treated with α-MSH, PL8331, PL8177, or PL5000, but not from EAU mice treated with MT-II, or PG901. Our previous studies show the melanocortin system's importance in maintaining ocular immune privilege and that α-MSH-treatment accelerates recovery and induces retinal-antigen-specific regulatory immunity in EAU. Our current results show that this activity is centered around MC1r and MC5r. In addition, the results suggest that a therapeutic potential to target MC1r and MC5r together to suppress uveitis induces regulatory immunity with potentially maintaining a normal retinal structure.

"Bilateral Sequential Acute Macular Neuroretinopathy in an Asian Indian Female with β Thalassemia Trait following (Corona Virus Disease) COVID-19 Vaccination and Probable Recent COVID Infection- Multimodal Imaging Study."

INTRODUCTION

Corona virus disease (COVID-19) has been associated with a variety of ophthalmic manifestations including acute macular neuroretinopathy and paracentral middle maculopathy. Posterior segment manifestations after post COVID-19 vaccinations have been reported.

CASE REPORT

A 25- year-old Asian Indian female developed sequential bilateral AMN following a single dose of COVISHIELD™ vaccine. On investigations she was found to have a β thalassemia trait. Presentation started unilaterally and progressed to the other eye after a month. On clinical examination, the fundus was apparently normal in both eyes. Significant changes suggestive of AMN were seen on multimodal imaging of the posterior segment of the respective eye at the time of involvement which resolved spontaneously in due course.

CONCLUSION

We report a temporal association of COVID-19 vaccination and AMN.

Bilateral acute macular neuroretinopathy in a young woman after the first dose of Oxford-AstraZeneca COVID-19 vaccine

Purpose

To report a case of bilateral acute macular neuroretinopathy following the first dose of Oxford-AstraZeneca COVID-19 (coronavirus disease 2019) vaccine in a young, Caucasian, and healthy woman.

Observations

A 25-year-old Caucasian female patient presented to the ophthalmology department of Dijon University Hospital with a 3-week history of black spots and paracentral scotoma in both eyes. She had no past medical history and was using the combined estrogen-progestin oral contraceptive (COC). These symptoms occurred 24 h after receiving the first Oxford-AstraZeneca COVID-19 vaccination dose. The ophthalmologic signs were preceded a few hours earlier by fever and flu-like symptoms. Ophthalmologic examination revealed a preserved visual acuity with a quiet anterior segment and normal fundus in both eyes. Findings on multimodal retinal imaging, particularly near-infrared reflectance (NIR) and optical coherence tomography (OCT) imaging, were classical of an acute macular neuroretinopathy in both eyes.

Conclusions and importance

COVID-19 vaccination is justified as an essential public health measure. Acute macular neuroretinopathy may occur in patient receiving a COVID-19 vaccination dose. Further reports are needed to confirm this association. Physicians should be aware of this complication and request an eye examination with at least OCT or NIR imaging in the case of any visual symptoms after vaccination, notably in young women using COC.

Optic neuropathy after COVID-19 vaccination: Case report and systematic review

Purpose

: To report a case of anterior ischemic optic neuropathy (AION) following COVID-19 vaccination and provide a systematic review of all published cases of optic neuropathy following COVID-19 vaccination.

Methods

: A systematic literature search was performed using PubMed and Ovid MEDLINE for cases of optic neuropathy following COVID-19 vaccination. Terms used in the search included “COVID-19 vaccination”, “optic neuropathy”, “optic neuritis”, and “ischemic optic neuropathy”. Titles and abstracts were initially screened then full texts of eligible studies were reviewed for data extraction. Only cases published in the English language, peer reviewed, and that included details on optic nerve involvement were included. All study types were eligible for inclusion.

Results

: Including our patient, a total of 10 patients (8 females) were identified as developing optic neuropathy following COVID-19 vaccination. Five patients (50.0%) were diagnosed with AION, while 4 (40.0%) were diagnosed with optic neuritis. One patient was diagnosed with papillitis and neuroretinitis. Three patients (30.0%) had bilateral involvement. Mean age of patients was 48.5±19.7 years. Mean time from vaccination to onset of ophthalmic symptoms was 6.5±6.4 days. Median (IQR) presenting visual acuity was logMAR 0.3 (0-1). For the 8 eyes which had both presenting and final follow-up visual acuity, median (IQR) presenting vision was logMAR 0.2 (0-0.7) and at final follow-up was logMAR 0 (0-0.05) (P=0.184).

Conclusion

: COVID-19 vaccination may result in optic neuropathy in the form of optic neuritis and ischemic optic neuropathy. Further studies are needed to determine the incidence, management, and prognosis of optic neuropathies associated with COVID-19 vaccination.

Translational advances of melanocortin drugs: Integrating biology, chemistry and genetics

Melanocortin receptors have emerged as important targets with a very unusual versatility, as their widespread distribution on multiple tissues (e.g. skin, adrenal glands, brain, immune cells, exocrine glands) together with the variety of physiological processes they control (pigmentation, cortisol release, satiety mechanism, inflammation, secretions), place this family of receptors as genuine therapeutic targets for many disorders. This review focuses in the journey of the development of melanocortin receptors as therapeutic targets from the discovery of their existence in the early 1990 s to the approval of the first few drugs of this class. Two major areas of development characterise the current state of melanocortin drug development: their role in obesity, recently culminated with the approval of setmelanotide, and their potential for the treatment of chronic inflammatory and autoimmune diseases like rheumatoid arthritis, multiple sclerosis or fibrosis. The pro-resolving nature of these drugs offers the advantage of acting by mimicking the way our body naturally resolves inflammation, expecting fewer side effects and a more balanced (i.e. non-immunosuppressive) response from them. Here we also review the approaches followed for the design and development of novel compounds, the importance of the GPCR nature of these receptors in the process of drug development, therapeutic value, current challenges and successes, and the potential for the implementation of precision medicine approaches through the incorporation of genetics advances.

The Role of Retinal Pigment Epithelial Cells in Regulation of Macrophages/Microglial Cells in Retinal Immunobiology

The ocular tissue microenvironment is immune privileged and uses several mechanisms of immunosuppression to prevent the induction of inflammation. Besides being a blood-barrier and source of photoreceptor nutrients, the retinal pigment epithelial cells (RPE) regulate the activity of immune cells within the retina. These mechanisms involve the expression of immunomodulating molecules that make macrophages and microglial cells suppress inflammation and promote immune tolerance. The RPE have an important role in ocular immune privilege to regulate the behavior of immune cells within the retina. Reviewed is the current understanding of how RPE mediate this regulation and the changes seen under pathological conditions.