Electron microscopic analysis of the influence of iPSC-derived motor neurons on bioengineered human skeletal muscle tissues.

3D bioengineered skeletal muscle macrotissues are increasingly important for studies of cell biology and development of therapeutics. Tissues derived from immortalized cells obtained from patient samples, or from pluripotent stem cells, can be co-cultured with motor-neurons to create models of human neuromuscular junctions in culture. In this study, we present foundational work on 3D cultured muscle ultrastructure, with and without motor neurons, which is enabled by the development of a new co-culture platform.

Understanding how ageing impacts ganglion cell susceptibility to injury in glaucoma.

Glaucoma is a leading cause of blindness worldwide, with a marked increase in prevalence with advancing age. Due to the multifactorial nature of glaucoma pathogenesis, dissecting how ageing impacts upon glaucoma risk requires analysis and synthesis of evidence from a vast literature. While there is a wealth of human clinical studies examining glaucoma pathogenesis and why older patients have increased risk, many aspects of the disease such as adaptations of retinal ganglion cells to stress, autophagy and the role of glial cells in glaucoma, require the use of animal models to study the complex cellular processes and interactions.

Increased disparities associated with black women and abnormal cervical cancer screening follow-up.

Background: To determine whether race and ethnicity impacts patient adherence to follow-up for colposcopy after abnormal cervical cancer screening.

Methods: This retrospective chart review included women that were randomly selected from patients presenting to our colposcopy clinic from 1/2019 to 12/2019. Inclusion criteria were females age ≥21 years-old and appropriate referral for colposcopy.

Comprehensiveness of Online Information in Gender-Affirming Surgery: Current Trends and Future Directions in Academic Plastic Surgery.

Background: Despite high rates of online misinformation, transgender and gender diverse (TGD) patients frequently utilize online resources to identify suitable providers of gender-affirming surgical care.

Aim: The objective of this study was to analyze the webpages of United States academic plastic surgery programs for the types of gender-affirming surgery (GAS) procedures offered and to determine how this correlates with the presence of an institutional transgender health program and geographic region in order to identify potential gaps for improvement.

Methods: Online institutional webpages of 82 accredited academic plastic surgery programs were analyzed for the presence of the following: GAS services, specification of type of GAS by facial, chest, body and genital surgery, and presence of a concomitant institutional transgender health program.

Electrophysiological analysis of healthy and dystrophic 3-D bioengineered skeletal muscle tissues.

Recently, methods for creating three-dimensional (3-D) human skeletal muscle tissues from myogenic cell lines have been reported. Bioengineered muscle tissues are contractile and respond to electrical and chemical stimulation. In this study, we provide an electrophysiological analysis of healthy and dystrophic 3-D bioengineered skeletal muscle tissues, focusing on Duchenne muscular dystrophy (DMD).

Disruption of Drosophila larval muscle structure and function by UNC45 knockdown.

Background: Proper muscle function is heavily dependent on highly ordered protein complexes. UNC45 is a USC (named since this region is shared by three proteins UNC45/CRO1/She4P) chaperone that is necessary for myosin incorporation into the thick filaments. UNC45 is expressed throughout the entire Drosophila life cycle and it has been shown to be important during late embryogenesis when initial muscle development occurs.

De novo revertant fiber formation and therapy testing in a 3D culture model of Duchenne muscular dystrophy skeletal muscle.

The biological basis of Duchenne muscular dystrophy (DMD) pathology is only partially characterized and there are still few disease-modifying therapies available, therein underlying the value of strategies to model and study DMD. Dystrophin, the causative gene of DMD, is responsible for linking the cytoskeleton of muscle fibers to the extracellular matrix beyond the sarcolemma. We posited that disease-associated phenotypes not yet captured by two-dimensional culture methods would arise by generating multinucleated muscle cells within a three-dimensional (3D) extracellular matrix environment.

A 3D culture model of innervated human skeletal muscle enables studies of the adult neuromuscular junction.

Two-dimensional (2D) human skeletal muscle fiber cultures are ill-equipped to support the contractile properties of maturing muscle fibers. This limits their application to the study of adult human neuromuscular junction (NMJ) development, a process requiring maturation of muscle fibers in the presence of motor neuron endplates. Here we describe a three-dimensional (3D) co-culture method whereby human muscle progenitors mixed with human pluripotent stem cell-derived motor neurons self-organize to form functional NMJ connections.

A Model of Glaucoma Induced by Circumlimbal Suture in Rats and Mice.

The circumlimbal suture is a technique for inducing experimental glaucoma in rodents by chronically elevating intraocular pressure (IOP), a well-known risk factor for glaucoma. This protocol demonstrates a step-by-step guide on this technique in Long Evans rats and C57BL/6 mice. Under general anesthesia, a "purse-string" suture is applied on the conjunctiva, around the equator and behind the limbus of the eye.

Characterization of the Circumlimbal Suture Model of Chronic IOP Elevation in Mice and Assessment of Changes in Gene Expression of Stretch Sensitive Channels.

To consider whether a circumlimbal suture can be used to chronically elevate intraocular pressure (IOP) in mice and to assess its effect on retinal structure, function and gene expression of stretch sensitive channels. Anesthetized adult C57BL6/J mice had a circumlimbal suture (10/0) applied around the equator of one eye. In treated eyes ( = 23) the suture was left in place for 12 weeks whilst in sham control eyes the suture was removed at day two ( = 17).

The Eye As a Biomarker for Alzheimer's Disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder resulting in dementia and eventual death. It is the leading cause of dementia and the number of cases are projected to rise in the next few decades. Pathological hallmarks of AD include the presence of hyperphosphorylated tau and amyloid protein deposition.

Reversal of functional loss in a rat model of chronic intraocular pressure elevation.

Purpose: This pilot study considered whether intraocular pressure (IOP) lowering could reverse ganglion cell dysfunction in a rat model of chronic ocular hypertension.

Methods: A circumlimbal suture was applied in one eye to induce ocular hypertension (n = 7) in Long-Evans rats. The contralateral eye served as an untreated control.

The influence of postsynaptic structure on missing quanta at the Drosophila neuromuscular junction.

Background: Synaptic transmission requires both pre- and post-synaptic elements for neural communication. The postsynaptic structure contributes to the ability of synaptic currents to induce voltage changes in postsynaptic cells. At the Drosophila neuromuscular junction (NMJ), the postsynaptic structure, known as the subsynaptic reticulum (SSR), consists of elaborate membrane folds that link the synaptic contacts to the muscle, but its role in synaptic physiology is poorly understood.

Simultaneous Recording of Electroretinography and Visual Evoked Potentials in Anesthetized Rats.

The electroretinogram (ERG) and visual evoked potential (VEP) are commonly used to assess the integrity of the visual pathway. The ERG measures the electrical responses of the retina to light stimulation, while the VEP measures the corresponding functional integrity of the visual pathways from the retina to the primary visual cortex following the same light event. The ERG waveform can be broken down into components that reflect responses from different retinal neuronal and glial cell classes.

Retinal Electrophysiology Is a Viable Preclinical Biomarker for Drug Penetrance into the Central Nervous System.

Objective. To examine whether retinal electrophysiology is a useful surrogate marker of drug penetrance into the central nervous system (CNS). Materials and Methods.

Contrast-based sensorless adaptive optics for retinal imaging.

Conventional adaptive optics ophthalmoscopes use wavefront sensing methods to characterize ocular aberrations for real-time correction. However, there are important situations in which the wavefront sensing step is susceptible to difficulties that affect the accuracy of the correction. To circumvent these, wavefront sensorless adaptive optics (or non-wavefront sensing AO; NS-AO) imaging has recently been developed and has been applied to point-scanning based retinal imaging modalities.

The effect of intraocular and intracranial pressure on retinal structure and function in rats.

An increasing number of studies indicate that the optic nerve head of the eye is sensitive not only to changes in intraocular pressure (IOP), but also to intracranial pressure (ICP). This study examines changes to optic nerve and retinal structure in a rat model in response to a range of IOP and ICP levels using optical coherence tomography. Furthermore, we examine the functional sequelae of these structural changes by quantifying the effect of pressure changes on the electroretinogram.

Chronic ocular hypertension induced by circumlimbal suture in rats.

Purpose: To induce chronic intraocular pressure (IOP) elevation in rat eyes by circumlimbal suture.

Methods: Anesthetized (isoflurane) Long-Evans rats underwent unilateral circumlimbal suture implantation while the fellow eyes served as untreated controls (n = 15). A sham group (n = 8) received the same procedure except that the suture was loosely tied.

Chronic hypertension increases susceptibility to acute IOP challenge in rats.

Purpose: To consider the effect of chronic arterial hypertension on the susceptibility of the retina to acute IOP challenge.

Methods: Anesthetized adult Long-Evans rats with normal (n = 5, receiving saline subcutaneously), chronic high blood pressure (BP) for 4 weeks (n = 15, Angiotensin II subcutaneously), and acute high BP for 1 hour (n = 10, Angiotensin II intravenously) underwent IOP elevation (10-120 mm Hg, 5 mm Hg steps each 3 minutes). During IOP elevation, retinal function and ocular blood flow were monitored with electroretinogram (ERG) and laser-Doppler flowmetry (LDF), respectively.

Quantitative spatial and temporal analysis of fluorescein angiography dynamics in the eye.

Purpose: We describe a novel approach to analyze fluorescein angiography to investigate fluorescein flow dynamics in the rat posterior retina as well as identify abnormal areas following laser photocoagulation.

Methods: Experiments were undertaken in adult Long Evans rats. Using a rodent retinal camera, videos were acquired at 30 frames per second for 30 seconds following intravenous introduction of sodium fluorescein in a group of control animals (n = 14).

The effect of ageing on ocular blood flow, oxygen tension and retinal function during and after intraocular pressure elevation.

Purpose: To investigate the effect of ageing on the recovery of ocular blood flow, intravitreal oxygen tension and retinal function during and after intraocular pressure (IOP) elevation.

Methods: Long Evans rats (3- and 14-month-old) underwent acute stepwise IOP elevation from 10 to 120 mmHg (5 mmHg steps each 3 minutes). IOP was then returned to baseline and recovery was monitored for 2 hours.

Coupling blood flow and neural function in the retina: a model for homeostatic responses to ocular perfusion pressure challenge.

Retinal function is known to be more resistant than blood flow to acute reduction of ocular perfusion pressure (OPP). To understand the mechanisms underlying the disconnect between blood flow and neural function, a mathematical model is developed in this study, which proposes that increased oxygen extraction ratio compensates for relative ischemia to sustain retinal function. In addition, the model incorporates a term to account for a pressure-related mechanical stress on neurons when OPP reduction is achieved by intraocular pressure (IOP) elevation.

Identifying cell class specific losses from serially generated electroretinogram components.

Purpose: Processing of information through the cellular layers of the retina occurs in a serial manner. In the electroretinogram (ERG), this complicates interpretation of inner retinal changes as dysfunction may arise from "upstream" neurons or may indicate a direct loss to that neural generator. We propose an approach that addresses this issue by defining ERG gain relationships.

Conscious wireless electroretinogram and visual evoked potentials in rats.

The electroretinogram (ERG, retina) and visual evoked potential (VEP, brain) are widely used in vivo tools assaying the integrity of the visual pathway. Current recordings in preclinical models are conducted under anesthesia, which alters neural physiology and contaminates responses. We describe a conscious wireless ERG and VEP recording platform in rats.