Protective Effects of Memantine on Hydroquinone-Treated Human Retinal Pigment Epithelium Cells and Human Retinal Muller Cells

Purpose: Memantine (MEM) acts on the glutamatergic system by blocking N-methyl-d-aspartate (NMDA) glutamate receptors. The role that MEM plays in protecting retinal cells is unknown. Hydroquinone (HQ) is one of the cytotoxic components in cigarette smoke. In the present study, we tested whether pretreatment with MEM could protect against the cytotoxic effects of HQ on human retinal pigment epithelium cells (ARPE-19) and human retinal Müller cells (MIO-M1) in vitro. Methods: Cells were plated, pretreated for 6 h with 30 μM of MEM, and then exposed for 24 h to 200, 100, 50, and 25 μM of HQ while MEM was still present. Cell viability (CV), reactive oxygen species (ROS), mitochondrial membrane potential (ΔΨm), and lactate dehydrogenase (LDH) release assays were performed. Results: HQ-treated cells showed a dose-dependent decrease in CV and ΔΨm, but an increase in ROS production and LDH levels in both cell lines. MEM pretreatment reversed the CV in 50, 100, and 200 μM doses in ARPE-19 cells and at all HQ concentrations in MIO-M1 cells compared to HQ-treated cultures. ROS production was reversed in all HQ concentrations in both cell lines. ΔΨm was significantly increased after MEM pretreatment only in 50 μM HQ concentration for both cell lines. LDH levels were decreased at 50 and 25 μM HQ in ARPE-19 and MIO-M1 cells, respectively. Conclusion: HQ-induced toxicity is concentration dependent in ARPE-19 and MIO-M1 cultures. MEM exerts protective effects against HQ-induced toxicity on human retinal pigment epithelial and Müller cells in vitro

Sleep disturbances in an arctic population: The Tromsø Study

<p>Abstract</p> <p>Background</p> <p>Prevalence estimates for insomnia range from 10 to 50% in the adult general population. Sleep disturbances cause great impairment in quality of life, which might even rival or exceed the impairment in other chronic medical disorders. The economic implications and use of health-care services related to chronic insomnia represent a clinical concern as well as a pronounced public health problem. Hypnotics are frequently prescribed for insomnia, but alcohol and over-the-counter sleep aids seem to be more widely used by insomniacs than prescription medications. Despite the complex relationship between insomnia and physical and mental health factors, the condition appears to be underrecognized and undertreated by health care providers, probably due to the generally limited knowledge of the causes and natural development of insomnia.</p> <p>Methods/Design</p> <p>The Tromsø Study is an ongoing population-based cohort study with five previous health studies undertaken between 1974 and 2001. This protocol outlines a planned study within the sixth Tromsø Study (Tromsø VI), aiming at; 1) describing sleep patterns in a community-based sample representative of the general population of northern Norway, and 2) examining outcome variables of sleep disturbances against possible explanatory and confounding variables, both within a cross-sectional approach, as well as retrospectively in a longitudinal study – exploring sleep patterns in subjects who have attended two or more of the previous Tromsø studies between 1974 and 2009. First, we plan to perform a simple screening in order to identify those participants with probable sleep disturbances, and secondly to investigate these sleep disturbances further, using an extensive sleep-questionnaire. We will also collect biological explanatory variables, i.e. blood samples, weight, height and blood pressure. We plan to merge data on an individual level from the Tromsø VI Study with data from the Norwegian Prescription Database (NorPD), which is a national registry including data for all prescription drugs issued at Norwegian pharmacies. Participants with sleep disturbances will be compared with pair-matched controls without sleep disturbances.</p> <p>Discussion</p> <p>Despite ongoing research, many challenges remain in the characterization of sleep disturbances and its correlates. Future mapping of the biological dimensions, natural history, as well as the behavioral and drug-related aspects of sleep disturbances in a representative population samples is clearly needed.</p

Biosimilars in ophthalmology: &ldquo;Is there a big change on the horizon?&rdquo;

Ashish Sharma,1 Prahalad Reddy,1 Baruch D Kuppermann,2 Bandello Francesco,3 Anat Lowenstein41Department of Vitreoretina, Lotus Eye Hospital and Institute, Coimbatore, Tamil Nadu, India; 2Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, USA; 3Department of Ophthalmology, Scientific Institute San Raffaele, University Vita-Salute, Milano, Italy; 4Division of Ophthalmology, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel Abstract: Retinal disease management has witnessed remarkable advances in posterior segment pharmacotherapy with the development of anti-VEGF molecules such as Lucentis&reg; (ranibizumab), Eylea&reg; (aflibercept), and off-label bevacizumab (Avastin). The US patents for ranibizumab and aflibercept will expire in 2020 (though Regeneron has indicated that it might attempt to extend its US patent to June 2023 with additional patent claims), and their European patents will expire in 2022 and 2025. Aflibercept comes off patent in 2022 in People&rsquo;s Republic of China and Japan. As soon as each patent expires, biosimilar molecules could potentially come in the mainstream clinical practice as a more cost-efficient choice in the form of generic biosimilars. It is difficult to predict how significant this shift would be in terms of more cost-effective clinical management and how it will impact the care in developed and developing world. It is important for clinicians to have a clear understanding about ophthalmic biosimilars before the industry brings these molecules to the mainstream clinical use globally.Keywords: biosimilar, Razumab&reg;, Lucentis&reg;, Eylea&reg;, ophthalmolog