Full-Field Electroretinogram Responses in Rodent Models of Ganglion Cell Injury.

Preclinical studies of optic nerve injury models have led to significant insight into the mechanism underlying retinal ganglion cell neurodegeneration. During the process of ganglion cell injury, morphological changes can occur prior to gross structural changes and cell death. Similarly, following injury, functional changes can occur in the absence of substantive structural changes.

Retinal hyperspectral imaging in mouse models of Parkinson's disease and healthy aging.

Retinal hyperspectral imaging (HSI) is a non-invasive in vivo approach that has shown promise in Alzheimer's disease. Parkinson's disease is another neurodegenerative disease where brain pathobiology such as alpha-synuclein and iron overaccumulation have been implicated in the retina. However, it remains unknown whether HSI is altered in in vivo models of Parkinson's disease, whether it differs from healthy aging, and the mechanisms which drive these changes.

Levodopa Rescues Retinal Function in the Transgenic A53T Alpha-Synuclein Model of Parkinson's Disease.

Background: Loss of substantia nigra dopaminergic cells and alpha-synuclein (α-syn)-rich intraneuronal deposits within the central nervous system are key hallmarks of Parkinson's disease (PD). Levodopa (L-DOPA) is the current gold-standard treatment for PD. This study aimed to evaluate retinal changes in a transgenic PD model of α-syn overexpression and the effect of acute levodopa (L-DOPA) treatment.

Altered Outer Retinal Structure, Electrophysiology and Visual Perception in Parkinson's Disease.

Background: Visual biomarkers of Parkinson's disease (PD) are attractive as the retina is an outpouching of the brain. Although inner retinal neurodegeneration in PD is well-established this has overlap with other neurodegenerative diseases and thus outer retinal (photoreceptor) measures warrant further investigation.

Objective: To examine in a cross-sectional study whether clinically implementable measures targeting outer retinal function and structure can differentiate PD from healthy ageing and whether these are sensitive to intraday levodopa (L-DOPA) dosing.

Measuring the Full-Field Electroretinogram in Rodents.

Electroretinography allows for noninvasive functional assessment of the retina and is a mainstay for preclinical studies of retinal function in health and disease. The full-field electroretinogram is useful for a variety of applications as it returns a functional readout from each of the major cell classes within the retina: photoreceptors, bipolar cells, amacrine cells, and retinal ganglion cells. Rodent models are commonly employed in ocular degeneration studies due to the fast throughput of these mammalian species and the conservation of the electroretinogram from the preclinic to the clinic.

Retinal Assessment Using In Vivo Electroretinography and Optical Coherence Tomography in Rodent Models of Diabetes.

Electroretinography and optical coherence tomography imaging allow for non-invasive quantitative assessment of the retina. These approaches have become mainstays for identifying the very earliest impact of hyperglycemia on retinal function and structure in animal models of diabetic eye disease. Moreover, they are essential for assessing the safety and efficacy of novel treatment approaches for diabetic retinopathy.

Retinal alpha-synuclein accumulation correlates with retinal dysfunction and structural thinning in the A53T mouse model of Parkinson's disease.

Abnormal alpha-synuclein (α-SYN) protein deposition has long been recognized as one of the pathological hallmarks of Parkinson's disease's (PD). This study considers the potential utility of PD retinal biomarkers by investigating retinal changes in a well characterized PD model of α-SYN overexpression and how these correspond to the presence of retinal α-SYN. Transgenic A53T homozygous (HOM) mice overexpressing human α-SYN and wildtype (WT) control littermates were assessed at 4, 6, and 14  months of age (male and female,  = 15-29 per group).

Characterization of retinal function and structure in the MPTP murine model of Parkinson's disease.

In addition to well characterized motor symptoms, visual disturbances are increasingly recognized as an early manifestation in Parkinson's disease (PD). A better understanding of the mechanisms underlying these changes would facilitate the development of vision tests which can be used as preclinical biomarkers to support the development of novel therapeutics for PD. This study aims to characterize the retinal phenotype of a mouse model of dopaminergic dysfunction and to examine whether these changes are reversible with levodopa treatment.

Impact of the sleep apnea management group clinic on positive airway pressure adherence.

Background: Positive airway pressure (PAP) adherence is critical for managing obstructive sleep apnea (OSA). We postulate that group-based Sleep Apnea Management (SAM) clinic, which harnesses the benefits of providing mutual support as well as facilitates access to system-based resources and education, will confer improvements in PAP adherence.

Methods: Data from SAM clinic attendees from January 2017 to June 2018 were retrospectively analyzed.

Elucidating Predictors of Obesity Hypoventilation Syndrome in a Large Bariatric Surgery Cohort.

Although understanding predictors of obesity hypoventilation syndrome (OHS), a condition associated with increased morbidity and mortality, is of key importance for risk prediction, existing characterization is limited. We hypothesize that OHS patients referred for bariatric surgery have more severe obstructive sleep apnea and metabolic derangements compared with their eucapnic counterparts. A total of 1,718 patients undergoing polysomnography with end-tidal CO monitoring prior to bariatric surgery at Cleveland Clinic from September 2011 to September 2018 were included.