Abstract: In developed countries, age-related macular degeneration (AMD) is the main cause of visual impairment in the elderly. Though the etiology of AMD is still unclear, it has been well understood that vascular endothelial growth factor (VEGF) is involved in the development of aberrant vasculature that represents the neovascular AMD (nAMD). Hence, VEGF inhibition is a more effective way to control nAMD. Pegaptanib, ranibizumab, and aflibercept are three drugs approved by the US Food and Drug Administration (FDA) to treat nAMD. Bevacizumab (an anti-VEGF medication comparable to ranibizumab) is already widely used off label. Existing anti-VEGF medicines are made up of antibodies or pieces of antibodies. Synthetic designed ankyrin repeat proteins (DARPins) imitate antibodies introduced recently by evolutions in bioengineering technology. These agents are designed to have high specificity and affinity to a specific target, smaller molecular size, and better tissue penetration, making them more stable and longer-acting at less concentration. Abicipar pegol (Allergan, Dublin, Ireland) is a DARPin that interlocks all VEGF-A isoforms. It has a greater affinity for VEGF and a longer intraocular half-life than ranibizumab, making it a feasible anti-VEGF agent. This review describes the properties and efficacy of abicipar, the new anti-VEGF agent, in clinical practice, which aims to improve outcomes, safety, and treatment burden of nAMD.
Background: Continuous and primary in vitro cultures are largely used to study cellular mechanisms occurring in several pathologic-like or pathological conditions. Continuous cell lines allow to perform long-lasting experiments since they do not undergo senescence.
Methods: The immortalized Moorfields/Institute of Ophtalmology-Müller 1 (MIO-M1) cell type represents a valuable model to analyze the mechanistic pathways characterizing Müller glial cells, both in health and in disease. MIO-M1 can be used to dissect the response of these glial cells following treatments which mimic pathological condition. For instance, MIO-M1 are useful to study the response of this cell type to stress condition as the case of oxidative stress (OS) (cultured with hydrogen peroxide), pathological neovascularization (cultured with VEGF), hypoxic or hyperoxic condition (cultured in low or high oxygen chamber). On the other hand, primary cultures allow to specifically analyze cellular responses without the interference of the whole organ, although the experimental treatment is performed in vivo. Primary Müller cells can be used to perform electrophysiological analyses of different cell sites.
Discussion: We describe how to manage MIO-M1 cells and how to analyze their response to different stress conditions; moreover, we report how to isolate and identify primary Müller cells and how to perform patch clamp and single cell recordings on them.
Abstract: Animal models are crucial for the study of tumorigenesis and therapies in oncology research. Though rare, uveal melanoma (UM) is the most common intraocular tumor and remains one of the most lethal cancers. Given the limitations of studying human UM cells in vitro, animal models have emerged as excellent platforms to investigate disease onset, progression, and metastasis. Since Greene’s initial studies on hamster UM, researchers have dramatically improved the array of animal models. Animals with spontaneous tumors have largely been replaced by engrafted and genetically engineered models. Inoculation techniques continue to be refined and expanded. Newer methods for directed mutagenesis have formed transgenic models to reliably study primary tumorigenesis. Human UM cell lines have been used to generate rapidly growing xenografts. Most recently, patient-derived xenografts have emerged as models that closely mimic the behavior of human UM. Separate animal models to study metastatic UM have also been established. Despite the advancements, the prognosis has only recently improved for UM patients, especially in patients with metastases. There is a need to identify and evaluate new preclinical models. To accomplish this goal, it is important to understand the origin, methods, advantages, and disadvantages of current animal models. In this review, the authors present current and historic animal models for the experimental study of UM. The strengths and shortcomings of each model are discussed and potential future directions are explored.
Background: Retinopathy of prematurity (ROP) is considered as the most common reason for blindness in children, particularly in preterm infants. The disease is characterized by the dysregulation of angiogenic mechanisms due to preterm birth, leading ultimately to vascular abnormalities and pathological neovascularization (NV). Retinal detachment and vision loss could represent a concrete risk connected to the most severe forms of ROP, also characterized by inflammation and retinal cell death.
Methods: During the last decades, many animal models of oxygen-induced retinopathy (OIR) have been recognized as useful tools to study the mechanisms of disease, since they reproduce the hallmarks typical of human ROP. Indeed, modulation of retinal vascular development by exposure to different oxygen protocols is possible in these animals, reproducing the main pathological phenotypes of the disease. The easy quantification of abnormal NV and the possibility to perform electrophysiologic, histological and molecular analyses on these models, make OIR animals a fundamental instrument in studying the pathophysiology of ROP and the effects of novel treatments against the disease.
Discussion: Here, the most commonly used OIR protocols in rodents, such as mice and rats, are described as well as the main pathological outcomes typical of these models. Despite their limitations and variables which should be considered whilst using these models, OIR models display several characteristics which have also been confirmed in human patients, validating the usefulness of such animals in the pre-clinical research of ROP.
