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Fulltext Diabetic retinopathy: a comprehensive update on in vivo, in vitro and ex vivo experimental models

Sadikan MZ, Abdul Nasir NA, Lambuk L, Mohamud R, Reshidan NH, Low E, et al.

BMC Ophthalmol, 2023 Oct 19;23(1):421.
PMID: 37858128 DOI: 10.1186/s12886-023-03155-1

Diabetic retinopathy (DR), one of the leading causes of visual impairment and blindness worldwide, is one of the major microvascular complications in diabetes mellitus (DM). Globally, DR prevalence among DM patients is 25%, and 6% have vision-threatening problems among them. With the higher incidence of DM globally, more DR cases are expected to be seen in the future. In order to comprehend the pathophysiological mechanism of DR in humans and discover potential novel substances for the treatment of DR, investigations are typically conducted using various experimental models. Among the experimental models, in vivo models have contributed significantly to understanding DR pathogenesis. There are several types of in vivo models for DR research, which include chemical-induced, surgical-induced, diet-induced, and genetic models. Similarly, for the in vitro models, there are several cell types that are utilised in DR research, such as retinal endothelial cells, Müller cells, and glial cells. With the advancement of DR research, it is essential to have a comprehensive update on the various experimental models utilised to mimic DR environment. This review provides the update on the in vitro, in vivo, and ex vivo models used in DR research, focusing on their features, advantages, and limitations.

Matched MeSH terms: Retina/pathology
Fulltext Differential Action of Connexin Hemichannel and Pannexin Channel Therapeutics for Potential Treatment of Retinal Diseases

Mat Nor MN, Rupenthal ID, Green CR, Acosta ML

Int J Mol Sci, 2021 Feb 10;22(4).
PMID: 33578721 DOI: 10.3390/ijms22041755

Dysregulation of retinal function in the early stages of light-induced retinal degeneration involves pannexins and connexins. These two types of proteins may contribute to channels that release ATP, leading to activation of the inflammasome pathway, spread of inflammation and retinal dysfunction. However, the effect of pannexin channel block alone or block of both pannexin channels and connexin hemichannels in parallel on retinal activity in vivo is unknown. In this study, the pannexin channel blocker probenecid and the connexin hemichannel blocker tonabersat were used in the light-damaged rat retina. Retinal function was evaluated using electroretinography (ERG), retinal structure was analyzed using optical coherence tomography (OCT) imaging and the tissue response to light-induced injury was assessed immunohistochemically with antibodies against glial fibrillary acidic protein (GFAP), Ionized calcium binding adaptor molecule 1 (Iba-1) and Connexin43 (Cx43). Probenecid did not further enhance the therapeutic effect of connexin hemichannel block in this model, but on its own improved activity of certain inner retina neurons. The therapeutic benefit of blocking connexin hemichannels was further evaluated by comparing these data against results from our previously published studies that also used the light-damaged rat retina model. The analysis showed that treatment with tonabersat alone was better than probenecid alone at restoring retinal function in the light-damaged retina model. The results assist in the interpretation of the differential action of connexin hemichannel and pannexin channel therapeutics for potential treatment of retinal diseases.

Matched MeSH terms: Retina/drug effects*; Retina/pathology; Retina/radiation effects; Retinal Diseases/drug therapy*; Retinal Diseases/etiology; Retinal Diseases/pathology
Fulltext Differential effect of body mass index on the incidence of diabetes and diabetic retinopathy in two Asian populations

Chan JCY, Chee ML, Tan NYQ, Cheng CY, Wong TY, Sabanayagam C

Nutr Diabetes, 2018 03 07;8(1):16.
PMID: 29549238 DOI: 10.1038/s41387-018-0018-0

AIMS: To examine the association of body mass index (BMI) with the incidence of diabetes mellitus (DM) and diabetic retinopathy (DR) in Asians.
METHODS: We analysed data from 4101 adults (Malay, n = 1901 and Indian, n = 2200) who participated in the baseline (2004-2009) and 6-year follow-up (2011-2015) of two independent population-based studies with similar methodology in Singapore. BMI was categorised into normal (<25 kg/m2), overweight (25-29.9 kg/m2) and obese (≥30 kg/m2). DM was diagnosed as random plasma glucose ≥200 mg/dL, HbA1c ≥6.5% or self-reported physician diagnosed DM. DR was assessed from retinal photographs graded using a standard protocol. The associations of baseline BMI with incident DM and DR was examined using multivariable poisson regression models adjusting for potential confounders including duration of DM, family history of DM and HbA1c.
RESULTS: The incidence of DM was 12.8% and among 1586 participants with DM, the incidence of DR was 17.6% over a median follow-up period of 6.2 years. Compared to those with BMI

Matched MeSH terms: Retina/pathology
Fulltext Differential expression and role of hyperglycemia induced oxidative stress in epigenetic regulation of β1, β2 and β3-adrenergic receptors in retinal endothelial cells

Safi SZ, Qvist R, Yan GO, Ismail IS

BMC Med Genomics, 2014;7:29.
PMID: 24885710 DOI: 10.1186/1755-8794-7-29

Aberrant epigenetic profiles are concomitant with a spectrum of developmental defects and diseases. Role of methylation is an increasingly accepted factor in the pathophysiology of diabetes and its associated complications. This study aims to examine the correlation between oxidative stress and methylation of β1, β2 and β3-adrenergic receptors and to analyze the differential variability in the expression of these genes under hyperglycemic conditions.

Matched MeSH terms: Retina/pathology*
Fulltext Diffuse unilateral subacute neuroretinitis in a young boy: a case report

Guan-Fook N, Hayati AA, Raja-Azmi MN, Liza-Sharmini AT, Wan-Hazabbah WH, Zunaina E

Clin Ophthalmol, 2012;6:487-90.
PMID: 22536041 DOI: 10.2147/OPTH.S29806

We report a case of diffuse unilateral subacute neuroretinitis in a young boy with no clinical visualization of nematode. The diagnosis was made based on clinical findings and detection of Toxocara immunoglobulin G by Western blot test. An 11-year-old Malay boy presented with progressive blurring of vision in the left eye for a duration of 1 year. It was associated with intermittent floaters. Visual acuity in the left eye was 6/45 and improved to 6/24 with pinhole. There was positive relative afferent pupillary defect, impaired color vision, and presence of red desaturation in the left eye. There were occasional cells in the anterior chamber with no conjunctiva injection. Posterior segment examination revealed mild-to-moderate vitritis and generalized pigmentary changes of the retina with attenuated vessels. The optic disk was slightly hyperemic with mild edema. There was presence of multiple, focal, gray-white subretinal lesions at the inferior part of the retina. Full blood picture results showed eosinophilia with detection of Toxocara immunoglobulin G by Western blot test. Investigations for other infective causes and connective tissue diseases were negative. The diagnosis of diffuse unilateral subacute neuroretinitis secondary to Toxocara was made based on clinical findings and laboratory results. He was treated with oral albendazole 400 mg daily for 5 days and oral prednisolone 1 mg/kg with tapering doses over 6 weeks. At 1 month follow-up, the inflammation had reduced, and multiple, focal, gray-white subretinal lesions were resolved; however there was no improvement of vision.

Matched MeSH terms: Retina
Early effect of hydroxychloroquine therapy: relationship between cumulative dose and retinal thickness

Agarwal P, Wong YH, Das Gupta E, Agarwal R, Livingstone BI, Ramamurthy S, et al.

Cutan Ocul Toxicol, 2015;34(3):179-84.
PMID: 25068998 DOI: 10.3109/15569527.2014.938751

BACKGROUND: Hydroxychloroquine (HCQ) is widely used for long-term treatment of autoimmune diseases such as rheumatoid arthritis. However, its long-term use is known to be associated with visual changes due to retinal damage. Retinal damage associated with long-term HCQ therapy is preventable if the drug is discontinued early when the patients are still asymptomatic. In view of contrasting reports from previous studies, we investigated the association of prolonged HCQ therapy with retinal thickness in macular area.
METHODS: This study included 48 patients on long-term HCQ therapy and 38 healthy controls. All subjects underwent examination for corrected visual acuity, fundus photography, visual fields and SD-OCT for retinal thickness.
RESULTS: Visual acuity, visual fields, fundus photography and SD-OCT did not reveal changes consistent with diagnosis of established HCQ retinopathy in any of the subjects from HCQ group. Retinal thickness in central, parafoveal and perifoveal areas did not show significant differences between HCQ and control groups. However, we observed negative correlation between cumulative dose and retinal thickness in the parafoveal (p = 0.003) and perifoveal areas (p = 0.019) but not in the central area.
CONCLUSIONS: Correlation of cumulative dose with retinal thickness in parafoveal and perifoveal areas and not the central area is in accordance with the late appearance of HCQ-induced bull's eye retinopathy. Hence screening of asymptomatic patients using OCT seems to be of great importance for early detection of retinal changes.
KEYWORDS: Cumulative dose; OCT; hydroxychloroquine; retinal thickness

Matched MeSH terms: Retina/drug effects*; Retina/pathology
Early-Stage Multifocal Candida chorioretinitis in an Immunocompromised Woman

Chen KJ, Chou HD, Teh WM

Ophthalmol Retina, 2019 10;3(10):887.
PMID: 31585711 DOI: 10.1016/j.oret.2019.05.023
Matched MeSH terms: Retina/pathology*
Emerging innovations in nano-enabled therapy against age-related macular degeneration: A paradigm shift

Kumar Dubey S, Pradhan R, Hejmady S, Singhvi G, Choudhury H, Gorain B, et al.

Int J Pharm, 2021 May 01;600:120499.
PMID: 33753164 DOI: 10.1016/j.ijpharm.2021.120499

Age-related macular degeneration (AMD), a degenerative eye disease, is the major cause of irreversible loss of vision among individuals aged 50 and older. Both genetic and environmental factors are responsible for the progressive damage to central vision. It is a multifactorial retinal disease with features such as drusen, hypopigmentation and/or hyperpigmentation of the retinal pigment epithelium, and even choroidal neovascularization in certain patients. AMD is of two major forms: exudative (wet) and atrophic (dry) with changes affecting the macula leading to impaired vision. Although the retina remains an accessible portion for delivering drugs, there are no current options to cure or treat AMD. The existing expensive therapeutics are unable to treat the underlying pathology but display several side effects. However, recent innovations in nanotherapeutics provide an optimal alternative of drug delivery to treat the neovascular condition. These new-age technologies in the nanometer scale would enhance bioactivity and improve the bioavailability of drugs at the site of action to treat AMD. The nanomedicine also provides sustained release of the drug with prolonged retention after penetrating across the ocular tissues. In this review, the insights into the cellular and molecular mechanisms associated with the pathophysiology of AMD are provided. It also serves to review the current progress in nanoparticle-based drug delivery systems that offer feasible treatments in AMD.

Matched MeSH terms: Retina; Retinal Diseases; Retinal Pigment Epithelium
Fulltext Evaluation of outer retinal layers in diabetic macula edema treated with intravitreal ranibizumab

Nur Aqilah, S., Wong, H.S., Syed Zulkifli, S.Z., Mushawiahti, M.

Medicine & Health, 2018;13(1):88-96.
MyJurnal

Anti-vascular endothelial growth factor (VEGF) reduces choroidal thickness by choroidal hypoperfusion in diabetic macula oedema (DME) patients. Indirect effect of anti-VEGF towards outer retinal layers (ORL) which supplied by choroidal circulation has not been well described. We evaluate the ORL thickness between retinal pigment epithelium (RPE) with inner-segment-outer-segment photoreceptor junction (IS/OS) and RPE with external limiting membrane (ELM) in pre- and postintravitreal Ranibizumab (IVR) treated eyes with central foveal diabetic macula edema. A total of 60 eyes (40 patients) were analysed. ORL thickness measured with optical coherence tomography at pre- and post-injection day 1, week 4 and week 6. Mean thickness of RPE-IS/OS was statistically significant over time (p=0.023) but not for RPE-ELM (p=0.216). Thickness ratio between RPE-IS/OS and RPE-ELM and central subfoveal thickness (CST) both showed statistically significant result over time with p=0.038 and p=0.000, respectively. We observed an initial reduction of ORL thickness at day 1 followed by increased in thickness at week 4 with subsequent reduction at week 6 was observed. ORL is an aspect that can be explore and emphasized further in patients considered for IVR injections. The long-term effects of IVR to the ORL however could not be concluded due to short follow up period.

Matched MeSH terms: Retina; Retinal Pigment Epithelium
Fulltext Evaluation of retinal nerve fiber layer thickness and optic nerve functions in fellow eye of neuromyelitis optica with unilateral optic neuritis

Ong Chin Feng W, Wan Hitam WH

Taiwan J Ophthalmol, 2020 06 20;10(3):189-196.
PMID: 33110750 DOI: 10.4103/tjo.tjo_22_20

Purpose: Peripapillary retinal nerve fibre layer (RNFL) thickness might be useful in monitoring ongoing subclinical structural damage especially in eyes with no history of optic neuritis (ON) in neuromyelitis optica (NMO).
Objective: To evaluate the peripapillary RNFL thickness and optic nerve functions in fellow eye of NMO with unilateral optic neuritis.
Materials and Methods: A comparative cross-sectional study was conducted in 2 tertiary hospitals from August 2017 to May 2019. RNFL thickness and optic nerve functions were evaluated. Statistical analysis was performed using Statistical Package for Social Science version 24.
Results: A total of 26 NMO patients and 26 controls were involved in this study. The median age (IQR) of NMO patients was 32.5 (12) years old. The RNFL thickness was significantly reduced in NMO patients with non-ON eyes as compared to control group. Best corrected visual acuity between the 2 groups were comparable (0.20 vs 0.00, p=0.071). Contrast sensitivity was also reduced in NMO patients (non-ON eyes) at all 5 spatial frequencies. In NMO group, 34.6% have normal colour vision. The mean deviation (MD) of Humphrey visual field (HVF) was higher in NMO group (p<0.001). There was a moderate correlation between RNFL thickness and contrast sensitivity. Weak correlation was found between the RNFL thickness with visual acuity and mean deviation of visual field test.
Conclusion: Our study showed that the fellow eye of NMO patients with unilateral ON revealed a significant reduction in RNFL thickness and all the optic nerve functions have subtle early changes that signify a subclinical retinal damage.

Matched MeSH terms: Retina
Fulltext Expression of Endogenous Angiotensin-Converting Enzyme 2 in Human Induced Pluripotent Stem Cell-Derived Retinal Organoids

Ahmad Mulyadi Lai HI, Chou SJ, Chien Y, Tsai PH, Chien CS, Hsu CC, et al.

Int J Mol Sci, 2021 Jan 28;22(3).
PMID: 33525682 DOI: 10.3390/ijms22031320

Angiotensin-converting enzyme 2 (ACE2) was identified as the main host cell receptor for the entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its subsequent infection. In some coronavirus disease 2019 (COVID-19) patients, it has been reported that the nervous tissues and the eyes were also affected. However, evidence supporting that the retina is a target tissue for SARS-CoV-2 infection is still lacking. This present study aimed to investigate whether ACE2 expression plays a role in human retinal neurons during SARS-CoV-2 infection. Human induced pluripotent stem cell (hiPSC)-derived retinal organoids and monolayer cultures derived from dissociated retinal organoids were generated. To validate the potential entry of SARS-CoV-2 infection in the retina, we showed that hiPSC-derived retinal organoids and monolayer cultures endogenously express ACE2 and transmembrane serine protease 2 (TMPRSS2) on the mRNA level. Immunofluorescence staining confirmed the protein expression of ACE2 and TMPRSS2 in retinal organoids and monolayer cultures. Furthermore, using the SARS-CoV-2 pseudovirus spike protein with GFP expression system, we found that retinal organoids and monolayer cultures can potentially be infected by the SARS-CoV-2 pseudovirus. Collectively, our findings highlighted the potential of iPSC-derived retinal organoids as the models for ACE2 receptor-based SARS-CoV-2 infection.

Matched MeSH terms: Retina/cytology*; Retina/metabolism
Fulltext Feature-Based Retinal Image Registration Using D-Saddle Feature

Ramli R, Idris MYI, Hasikin K, A Karim NK, Abdul Wahab AW, Ahmedy I, et al.

J Healthc Eng, 2017;2017:1489524.
PMID: 29204257 DOI: 10.1155/2017/1489524

Retinal image registration is important to assist diagnosis and monitor retinal diseases, such as diabetic retinopathy and glaucoma. However, registering retinal images for various registration applications requires the detection and distribution of feature points on the low-quality region that consists of vessels of varying contrast and sizes. A recent feature detector known as Saddle detects feature points on vessels that are poorly distributed and densely positioned on strong contrast vessels. Therefore, we propose a multiresolution difference of Gaussian pyramid with Saddle detector (D-Saddle) to detect feature points on the low-quality region that consists of vessels with varying contrast and sizes. D-Saddle is tested on Fundus Image Registration (FIRE) Dataset that consists of 134 retinal image pairs. Experimental results show that D-Saddle successfully registered 43% of retinal image pairs with average registration accuracy of 2.329 pixels while a lower success rate is observed in other four state-of-the-art retinal image registration methods GDB-ICP (28%), Harris-PIIFD (4%), H-M (16%), and Saddle (16%). Furthermore, the registration accuracy of D-Saddle has the weakest correlation (Spearman) with the intensity uniformity metric among all methods. Finally, the paired t-test shows that D-Saddle significantly improved the overall registration accuracy of the original Saddle.

Matched MeSH terms: Retina
Fulltext Flourescein angiogram and funduscopic features of radiation induced retinopathy: a descriptive value of retinopathy severity in patients with nasopharyngeal carcinoma

Norshamsiah, M.D., Wan Haslina Wah, Kok, H.S., Sharifa Ezat, W.P., Fuad, I.

Medicine & Health, 2015;10(1):23-31.
MyJurnal

Radiation retinopathy (RR) is a known complication after radiotherapy for Nasopharyngeal Carcinoma (NPC). This study aims to relate the relationship of RR and radiation dose in patients with NPC through assessment with clinical
funduscopy and fundus fluorescein angiogram (FFA). A cross sectional study was conducted on patients with NPC who had completed radiotherapy treatment in the Oncology Clinic, Universiti Kebangsaan Malaysia Medical Centre (UKMMC). Eighty two eyes of 42 patients were examined and the prevalence of RR was found to be 35.4%. The severity of RR is strongly associated with the dose of radiation to the retina (Spearman correlation value=0.48; p<0.001). The common features of RR assessed by FFA were telangiectatic vessels (26.2%) and capillary non-perfusion (14.3%). Retinal neovasularization occurred in 10.7% of eyes. The level of visual deterioration correlated with the severity of RR with 26% of eyes experiencing a visual acuity of 6/18 or worse. More than one third of patients developed RR, with radiation maculopathy being the commonest cause for significant visual loss. FFA is a useful tool in detecting early signs of radiation retinopathy and maculopathy.
Keywords: nasopharyngeal carcinoma, fluorescein fundus angiography, retinopathy, radiotherapy
Study site: Oncology Clinic, Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM), Kuala Lumpur, Malaysia

Matched MeSH terms: Retina; Retinal Neovascularization
Fundus magnification produced during direct ophthalmoscopy of the corrected eye

Chung KM

Optom Vis Sci, 1999 Feb;76(2):121-6.
PMID: 10082059

The clinical significance of fundus magnification produced during direct ophthalmoscopy of the corrected eye has not been fully established. Based on paraxial ray tracing, fundus magnification (M) can be defined by a simple equation, M = (K'/4) x (Fs/K), where K' is the dioptric axial power of the eye, Fs is the correcting thin lens power and K is the ocular ametropia. Refractive myopes produce greater fundus magnification than axial myopes, whereas refractive hyperopes produce lower fundus magnification than axial hyperopes. If we assume 15 x fundus magnification as our standard magnification for an emmetropic reduced eye, then wearing glasses or putting the focusing lens at or close to the anterior focus of the eye is able to achieve the standard magnification for axial myope and axial hyperope, whereas wearing contact lenses is able to achieve the standard magnification for refractive myope and refractive hyperope. Vertex distance has greater influence on fundus magnification produced during direct ophthalmoscopy than other funduscopic techniques. In conclusion, the newly defined formula has clinical applications during direct ophthalmoscopy.

Matched MeSH terms: Retina/pathology*
Fulltext HbA1c and retinal sensitivity in diabetics using microperimetry

Sharanjeet-Kaur, Ismail SA, Mutalib HA, Ngah NF

J Optom, 2018 05 26;12(3):174-179.
PMID: 29843983 DOI: 10.1016/j.optom.2018.03.007

PURPOSE: The purpose of this study was to determine the relationship between HbA1c values and retinal sensitivity at central 10° using the MP-1 microperimeter.
METHODS: A prospective study was carried out on 32 healthy subjects (control group) and 60 diabetic patients. The diabetic patients were divided into 2 groups. Group 1 comprised of 30 patients without diabetic retinopathy (DR) and group 2 had 30 patients with mild non-proliferative DR. A full-threshold microperimetry of the central 10° of retina (the macula) was performed on all subjects, utilizing 32 points with the MP-1. The relationship between light sensitivity and HbA1c value was calculated using linear regression analysis.
RESULTS: Total mean sensitivity at 10° for group 1 without DR, group 2 with mild NPDR and control group were 18.67±0.83, 17.98±1.42 and 19.45±0.34 (dB), respectively. There was a significant difference in total mean retinal sensitivity at 10° between the 3 groups (F(2,89)=18.14, p=0.001). A simple linear regression was calculated to predict HbA1c based on retinal sensitivity. A significant regression equation was found (F(1,90)=107.61, p=0.0001, with an R2 of 0.545). The linear regression analysis revealed that there was a 0.64dB decline in mean retinal sensitivity within the central 10° diameter with an increase of 1mmHg of HbA1c.
CONCLUSION: Retinal sensitivity at the central 10° of the macula is affected by changes in HbA1c values.

Matched MeSH terms: Retina/physiopathology*
Fulltext Hidden Choroidal Melanoma Presented with Bullous Non-rhegmatogenous Retinal Detachment in a Myopic Asian Lady: A Rare Manifestation

Ibrahim N, Sakinah Z, Abdul Ghani Z, Ibrahim M

Cureus, 2019 Mar 27;11(3):e4335.
PMID: 31187000 DOI: 10.7759/cureus.4335

Choroidal melanoma is an uncommon malignant melanoma among non-Caucasians. We report here a case of a high myope patient who presented with symptoms of acute retinal detachment, which had been diagnosed as possible rhegmatogenous retinal detachment from the initial assessment. A detailed vitreoretinal evaluation revealed a glimpse of an obscured intraocular mass underneath the detached retina, which later proved to be a choroidal melanoma. This is an unexpected cause of retinal detachment in a myopic eye. Furthermore, the rare nature of choroidal melanoma in this particular region of the world makes this an ignored diagnosis at presentation.

Matched MeSH terms: Retina; Retinal Detachment
High dengue virus load differentially modulates human microvascular endothelial barrier function during early infection

Soe HJ, Khan AM, Manikam R, Samudi Raju C, Vanhoutte P, Sekaran SD

J Gen Virol, 2017 Dec;98(12):2993-3007.
PMID: 29182510 DOI: 10.1099/jgv.0.000981

Plasma leakage is the main pathophysiological feature in severe dengue, resulting from altered vascular barrier function associated with an inappropriate immune response triggered upon infection. The present study investigated functional changes using an electric cell-substrate impedance sensing system in four (brain, dermal, pulmonary and retinal) human microvascular endothelial cell (MEC) lines infected with purified dengue virus, followed by assessment of cytokine profiles and the expression of inter-endothelial junctional proteins. Modelling of changes in electrical impedance suggests that vascular leakage in dengue-infected MECs is mostly due to the modulation of cell-to-cell interactions, while this loss of vascular barrier function observed in the infected MECs varied between cell lines and DENV serotypes. High levels of inflammatory cytokines (IL-6 and TNF-α), chemokines (CXCL1, CXCL5, CXCL11, CX3CL1, CCL2 and CCL20) and adhesion molecules (VCAM-1) were differentially produced in the four infected MECs. Further, the tight junctional protein, ZO-1, was down-regulated in both the DENV-1-infected brain and pulmonary MECs, while claudin-1, PECAM-1 and VE-cadherin were differentially expressed in these two MECs after infection. Non-purified virus stock was also studied to investigate the impact of virus stock purity on dengue-specific immune responses, and the results suggest that virus stock propagated through cell culture may include factors that mask or alter the DENV-specific immune responses of the MECs. The findings of the present study show that high DENV load differentially modulates human microvascular endothelial barrier function and disrupts the function of inter-endothelial junctional proteins during early infection with organ-specific cytokine production.

Matched MeSH terms: Retina/cytology; Retina/immunology; Retina/virology
Hydroxychloroquine and Chloroquine in Prophylaxis and Treatment of COVID-19: What Is Known?

Shankar PR, Palaian S, Gulam SM

J Pharm Bioallied Sci, 2020 10 06;13(1):4-10.
PMID: 34084043 DOI: 10.4103/jpbs.JPBS_404_20

The corona virus disease-19 (COVID-19) pandemic has affected the entire world causing huge economic losses and considerable morbidity and mortality. Considering the explosive growth of the pandemic repurposing existing medicines may be cost-effective and may be approved for use in COVID-19 faster. Researchers and medical practitioners worldwide have explored the use of chloroquine and hydroxychloroquine, in few occasions combined with the macrolide antibiotic azithromycin, for COVID-19 treatment. These two drugs are economic and easily available, and hence gained attention as a potential option for COVID-19 management. As per the available evidence, the outcomes of treatments with these medications are conflicting from both the efficacy and safety (predominantly cardiac related) perspectives. Currently, multiple studies are underway to test the safety and efficacy of these medications and more results are expected in the near future. The retina, the endocrine system (with risk of hypoglycemia), the musculoskeletal system, the hematological system, and the neurological system may also be affected. The use of these drugs is contraindicated in patients with arrhythmias, known hypersensitivity, and in patients on amiodarone. In addition to the published literature, personal communication with doctors treating COVID-19 patients seems to suggest the drugs may be effective in reducing symptoms and hastening clinical recovery. The literature evidence is still equivocal and further results are awaited. There has been recent controversy including retraction of articles published in prestigious journals about these medicines. Their low cost, long history of use, and easy availability are positive factors with regard to use of these drugs in COVID-19.

Matched MeSH terms: Retina
Fulltext Images in clinical medicine. Retinal detachment in malignant hypertension

Tajunisah I, Patel DK

N Engl J Med, 2009 Aug 27;361(9):899.
PMID: 19710488 DOI: 10.1056/NEJMicm0802683
Matched MeSH terms: Retina/pathology*; Retinal Detachment/etiology*; Retinal Detachment/pathology
Fulltext Intracameral injection of ranibizumab caused regression of iris neovascularisation and clearance of hyphaema in a non-diabetic patient with ischaemic remnant retinal flap in a silicone filled eye

Bastion ML

BMJ Case Rep, 2010;2010.
PMID: 22242074 DOI: 10.1136/bcr.10.2009.2398

The use of 0.5 mg/0.05 ml of ranibizumab intracamerally, to induce regression of iris neovascularisation in a non-diabetic patient, is reported. A 55-year-old Malay man presented with left eye rubeosis and hyphaema secondary to ischaemic remnant retinal flap in his silicone filled pseudophakic eye. Regression of rubeosis and resolution of hyphaema was noted within 4 days of injection of intracameral ranibizumab, allowing repeat vitrectomy to be performed without much bleeding, thus facilitating removal of his intraocular lens and laser to remaining flap. One month postoperatively he remained comfortable with counting fingers vision similar to the pre-hyphaema period.

Matched MeSH terms: Retina

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