Evidence for Diffuse Central Retinal Edema In Vivo in Diabetic Male Sprague Dawley Rats

Background: Investigations into the mechanism of diffuse retinal edema in diabetic subjects have been limited by a lack of animal models and techniques that co-localized retinal thickness and hydration in vivo. In this study we test the hypothesis that a previously reported supernormal central retinal thickness on MRI measured in experimental diabetic retinopathy in vivo represents a persistent and diffuse edema. Methodology/Principal Findings: In diabetic and age-matched control rats, and in rats experiencing dilutional hyponatremia (as a positive edema control), whole central retinal thickness, intraretinal water content and apparent diffusion coefficients (ADC, ‘water mobility’) were measured in vivo using quantitative MRI methods. Glycated hemoglobin and retinal thickness ex vivo (histology) were also measured in control and diabetic groups. In the dilutional hyponatremia model, central retinal thickness and water content were supernormal by quantitative MRI, and intraretinal water mobility profiles changed in a manner consistent with intracellular edema. Groups of diabetic (2, 3, 4, 6, and 9 mo of diabetes), and age-matched controls were then investigated with MRI and all diabetic rats showed supernormal whole central retinal thickness. In a separate study in 4 mo diabetic rats (and controls), MRI retinal thickness and water content metrics were significantly greater than normal, and ADC was subnormal in the outer retina; the increase in retinal thickness was not detected histologically on sections of fixed and dehydrated retinas from these rats

The Portuguese Society of Rheumatology position paper on the use of biosimilars

Biotechnological drugs have become a fundamental resource for the treatment of rheumatic patients. Patent expiry of some of these drugs created the opportunity for biopharmaceutical manufacturers to develop biosimilar drugs intended to be as efficacious as the originator product but with a lower cost to healthcare systems. Due to the complex manufacturing process and highly intricate structure of biologicals, a biosimilar can never be an exact copy of its reference product. Consequently, regulatory authorities issued strict preclinical and clinical guidelines to ensure safety and efficacy equivalence and, in September 2013, the biosimilar of infliximab was the first biosimilar monoclonal antibody to be authorized for use in the European Union. The current document is a position statement of the "Sociedade Portuguesa de Reumatologia" (Portuguese Society of Rheumatology) on the use of biosimilar drugs in rheumatic diseases. Two systematic literature reviews were performed, one concerning clinical trials and the other one concerning international position papers on biosimilars. The results were presented and discussed in a national meeting and a final position document was discussed, written and approved by Portuguese rheumatologists. Briefly, this position statement is contrary to automatic substitution of the originator by the biosimilar, defends either a different INN or the prescription by brand name, supports that switching between biosimilars and the originator molecule should be done after at least 6 months of treatment and based on the attending physician decision and after adequate patient information, recommends the registration of all biosimilar treated patients in Reuma.pt for efficacy, safety and immunogenicity surveillance, following the strategy already ongoing for originators, and opposes to extrapolation of indications approved to the originator to completely different diseases and/or age groups without adequate pre-clinical, safety or efficacy data.info:eu-repo/semantics/publishedVersio