Purpose: Brimonidine is a selective alpha-2 adrenergic agonist used to reduce intraocular pressure and it has been shown to have some neuroprotective effects. Hydroquinone (HQ) is a toxicant present in cigarette smoke, and other sources. In this study, we investigated the cyto-protective effects in vitro of Brimonidine on human retinal pigment epithelium cells (ARPE-19) and human retinal Müller cells (MIO-M1) that had been treated with HQ.
Methods: Cells were pretreated for 6 h with different doses of Brimonidine tartrate 0.1% (1/2×, 1×, 5×, 10×), followed by a 24-h exposure to 100 μM of HQ, while the Brimonidine was still present. Assays were used to measure cell viability, mitochondrial membrane potential (ΔΨm), reactive oxygen species (ROS) production, and lactate dehydrogenase (LDH) release.
Results: Brimonidine increased the cell viability at all concentrations studied in both cell lines studied. ΔΨm also improved at all Brimonidine doses in ARPE-19 cells and in the 5× and 10× dosages MIO-M1 cells. The ROS levels decreased at 1×, 5×, and 10× doses of Brimonidine in ARPE-19 but only at 10× on MIO-M1 cells. The 10×-Brimonidine ARPE-19 cells had decreased LDH release, but no LDH changes were observed on MIO-M1 cells.
Conclusion: HQ-induced toxicity is mediated through mitochondrial damaging, oxidative stress-related and necrosis-related pathways; Brimonidine significantly prevented the mitochondrial damaging and oxidative stress-related effects but had little effect on blocking the necrosis component of HQ-toxicity. Brimonidine protective effects differ between the different retinal cell types and high concentrations of Brimonidine (10×) have minimal damaging effects on human retinal cells.
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http://dx.doi.org/10.1089/jop.2015.0083 | DOI Listing |
PLoS One
January 2025
Department of Neurology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.
Purpose: A relative afferent pupillary defect (RAPD) is a characteristic clinical sign of optic neuritis (ON). Here, we systematically evaluated ultrasound pupillometry (UP) for the detection of an RAPD in patients with ON, including a comparison with infrared video pupillometry (IVP), the gold standard for objective pupillometry.
Materials And Methods: We enrolled 40 patients with acute (n = 9) or past (n = 31) ON (ON+), 31 patients with multiple sclerosis (MS) without prior ON, and 50 healthy controls (HC) in a cross-sectional observational study.
JAMA Netw Open
January 2025
Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Importance: Determining spectacle-corrected visual acuity (VA) is essential when managing many ophthalmic diseases. If artificial intelligence (AI) evaluations of macular images estimated this VA from a fundus image, AI might provide spectacle-corrected VA without technician costs, reduce visit time, or facilitate home monitoring of VA from fundus images obtained outside of the clinic.
Objective: To estimate spectacle-corrected VA measured on a standard eye chart among patients with diabetic macular edema (DME) in clinical practice settings using previously validated AI algorithms evaluating best-corrected VA from fundus photographs in eyes with DME.
Invest Ophthalmol Vis Sci
January 2025
UCL Institute of Ophthalmology, University College London, London, United Kingdom.
Purpose: The purpose of this study was to analyze the retinal sensitivity under photopic, mesopic, and scotopic conditions in a cohort of patients affected with KCNV2-associated retinopathy.
Methods: Cross-sectional evaluation of molecularly confirmed individuals was conducted. Data were obtained prospectively.
Transl Vis Sci Technol
January 2025
Yale Cardiovascular Research Center, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA.
Purpose: Alteration of visual acuity in wet age-related macular degeneration (AMD) is mostly driven by vascular endothelial growth factor A (VEGF-A)-induced edema from leaky newly forming blood vessels below the retina layers. To date, all therapies aimed at alleviation of this process have relied on inhibition of VEGF-A activity. Although effective in preventing vascular leak and edema, this approach also leads to the loss of normal vasculature and multiple related side effects.
View Article and Find Full Text PDFTransl Vis Sci Technol
January 2025
FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
Purpose: Geographic atrophy (GA), an advanced form of dry age-related macular degeneration (AMD), has limited treatment options. This study introduces a novel mouse model featuring an expanding GA patch that can be used to test mechanisms and therapeutics.
Methods: C57Bl/6J male mice (n = 96) aged 9-10 weeks received an intraperitoneal (IP) injection of 20 mg/kg sodium iodate (NaIO3).
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