Rat Model of Type 2 Diabetes Mellitus Recapitulates Human Disease in the Anterior Segment of the Eye.

Changes in the anterior segment of the eye due to type 2 diabetes mellitus (T2DM) are not well-characterized, in part due to the lack of a reliable animal model. This study evaluated changes in the anterior segment, including crystalline lens health, corneal endothelial cell density, aqueous humor metabolites, and ciliary body vasculature, in a rat model of T2DM compared with human eyes. Male Sprague-Dawley rats were fed a high-fat diet (45% fat) or normal diet, and rats fed the high-fat diet were injected with streptozotocin intraperitoneally to generate a model of T2DM.

Type II Diabetes Mellitus Causes Extracellular Matrix Alterations in the Posterior Cornea That Increase Graft Thickness and Rigidity.

Purpose: There is a pressing need to investigate the impact of type II diabetes mellitus on the posterior cornea in donor tissues given its increasing prevalence and potential impact on endothelial keratoplasty surgical outcomes.

Methods: Immortalized human cultured corneal endothelial cells (CECs; HCEC-B4G12) were grown in hyperglycemic media for 2 weeks. Extracellular matrix (ECM) adhesive glycoprotein expression and advanced glycation end products (AGEs) in cultured cells and corneoscleral donor tissues, as well as the elastic modulus for the Descemet membrane (DMs) and CECs of diabetic and nondiabetic donor corneas, were measured.

Mitophagy: An Emerging Target in Ocular Pathology.

Mitochondrial function is essential for the viability of aerobic eukaryotic cells, as mitochondria provide energy through the generation of adenosine triphosphate (ATP), regulate cellular metabolism, provide redox balancing, participate in immune signaling, and can initiate apoptosis. Mitochondria are dynamic organelles that participate in a cyclical and ongoing process of regeneration and autophagy (clearance), termed mitophagy specifically for mitochondrial (macro)autophagy. An imbalance in mitochondrial function toward mitochondrial dysfunction can be catastrophic for cells and has been characterized in several common ophthalmic diseases.

Optimizing Visualization of Descemet Membrane Endothelial Keratoplasty Tissue: Assessing the Impact of Trypan Blue Exposure on Stain Duration and Corneal Endothelial Cell Function.

Purpose: To assess how trypan blue staining affects Descemet membrane endothelial keratoplasty (DMEK) graft visibility and corneal endothelial cell (CEC) mitochondrial respiration.

Methods: DMEK grafts (n = 20) were stained with trypan blue 0.06% for 1, 3, 5, or 10 minutes.

Ubiquinol Supplementation of Donor Tissue Enhances Corneal Endothelial Cell Mitochondrial Respiration.

Purpose: To determine whether ubiquinol improves mitochondrial function and cell viability in human donor corneal endothelial cells during hypothermic corneal tissue storage.

Methods: Endothelial cell Descemet membrane tissues were treated with 10 μM ubiquinol, the reduced form of the antioxidant coenzyme Q10, for 5 days in Optisol-GS storage media before assaying for mitochondrial activity using extracellular flux analysis of oxygen consumption. In addition, endothelial cell Descemet membrane tissues were analyzed for cell viability using apoptosis and necrosis assays.

DMEK outcomes using nondiabetic grafts for recipients with diabetes mellitus.

Purpose: To compare Descemet membrane endothelial keratoplasty (DMEK) outcomes using nondiabetic grafts in diabetic and nondiabetic recipients.

Methods: All eyes that underwent DMEK between February 2013 and October 2016 (follow-up ≥3 months, without prior keratoplasty) were included. Recipients were divided into diabetic (insulin dependent [IDDM] or noninsulin dependent [NIDDM]) and nondiabetic groups.

Efficacy and Safety of Various Amphotericin B Concentrations on Candida albicans in Cold Storage Conditions.

Purpose: To determine the concentration of amphotericin B that would be both effective against Candida albicans contamination and safe for corneal endothelial cells (CECs) in cold storage conditions.

Methods: Triplicate media cultures were inoculated with 10 colony-forming units (CFUs)/mL of C. albicans (American Type Culture Collection 10231), supplemented with amphotericin B (0-20 μg/mL), stored in cold conditions (2°C-8°C) for 72 hours, and analyzed quantitatively for CFUs.

Assessing the Effects of Ripasudil, a Novel Rho Kinase Inhibitor, on Human Corneal Endothelial Cell Health.

Purpose: To determine how the Rho kinase inhibitor, ripasudil, affects metabolic function and cell viability in donor human corneal endothelial cells (HCECs).

Methods: Endothelial cell-Descemet membrane (EDM) tissues were treated with 10 μM ripasudil and assayed for mitochondrial and glycolytic activity using extracellular flux analysis and then compared to untreated controls. In addition, EDM tissues with a 24-h ripasudil treatment and control tissues were exposed to 1 μM staurosporine to induce apoptosis and then analyzed for cell viability using apoptosis and necrosis assays.

Feeder-free differentiation of cells exhibiting characteristics of corneal endothelium from human induced pluripotent stem cells.

The purpose of this study was to devise a strategy for the derivation of corneal endothelial cells (CEnCs) from adult fibroblast-derived induced pluripotent stem cells (iPSCs). IPSCs were generated from an adult human with normal ocular history via expression of , , and Neural crest cells (NCCs) were differentiated from iPSCs via addition of CHIR99021 and SB4315542. NCCs were driven toward a CEnC fate via addition of B27, PDGF-BB and DKK-2 to CEnC media.

Proteomic analysis of corneal endothelial cell-descemet membrane tissues reveals influence of insulin dependence and disease severity in type 2 diabetes mellitus.

The objective of this study was to characterize the proteome of the corneal endothelial cell layer and its basement membrane (Descemet membrane) in humans with various severities of type II diabetes mellitus compared to controls, and identify differentially expressed proteins across a range of diabetic disease severities that may influence corneal endothelial cell health. Endothelium-Descemet membrane complex tissues were peeled from transplant suitable donor corneas. Protein fractions were isolated from each sample and subjected to multidimensional liquid chromatography and tandem mass spectrometry.

The Narrow Abdomen Ion Channel Complex Is Highly Stable and Persists from Development into Adult Stages to Promote Behavioral Rhythmicity.

The sodium leak channel NARROW ABDOMEN (NA)/ NALCN is an important component of circadian pacemaker neuronal output. In , rhythmic expression of the NA channel regulator in a subset of adult pacemaker neurons has been proposed to contribute to circadian regulation of channel localization or activity. Here we have restricted expression of NA channel subunits or the regulator to either development or adulthood using the temperature-inducible -GAL80 system.

Mitochondrial and Morphologic Alterations in Native Human Corneal Endothelial Cells Associated With Diabetes Mellitus.

Purpose: To characterize changes in the energy-producing metabolic activity and morphologic ultrastructure of corneal endothelial cells associated with diabetes mellitus.

Methods: Transplant suitable corneoscleral tissue was obtained from donors aged 50 to 75 years. We assayed 3-mm punches of endothelium-Descemet membrane for mitochondrial respiration and glycolysis activity using extracellular flux analysis of oxygen and pH, respectively.

Assessing the Impact of Diabetes Mellitus on Donor Corneal Endothelial Cell Density.

Purpose: To quantify changes in endothelial cell density (ECD) of donor corneal tissue in relation to the presence or absence of a medical history of diabetes mellitus diagnosis, treatment, and complications.

Methods: A retrospective review was performed for all corneas collected at Iowa Lions Eye Bank between January 2012 and December 2015. For purposes of analysis, donor corneas were divided into 4 groups: nondiabetic, non-insulin-dependent diabetic, insulin-dependent diabetic without medical complications due to diabetes, and insulin-dependent diabetic with medical complications due to diabetes.

Incidence and Outcomes of Positive Donor Corneoscleral Rim Fungal Cultures after Keratoplasty.

Purpose: To determine the incidence of positive corneoscleral donor rim fungal cultures after keratoplasty and to report clinical outcomes of grafts with culture-positive donor rims.

Design: Retrospective cohort study.

Participants: Consecutive donor corneas and keratoplasty recipients at a single tertiary referral center over 20 years.

Descemet membrane adhesion strength is greater in diabetics with advanced disease compared to healthy donor corneas.

Descemet membrane endothelial keratoplasty (DMEK) is an increasingly popular surgical procedure for treating ocular diseases that require a corneal transplant. Previous studies have found that tissue tearing during surgical preparation is more likely elevated in eyes from donors with a history of diabetes mellitus. To quantify these potential differences, we established an experimental technique for quantifying the force required to separate the endothelium-Descemet membrane complex (EDM) from stroma in human donor corneal tissue, and we assessed differences in adhesion strength between diabetic and non-diabetic donor corneas.

Incidence of Cystoid Macular Edema After Descemet Membrane Endothelial Keratoplasty as a Staged and Solitary Procedure.

Purpose: To compare the incidence of visually significant postoperative cystoid macular edema (CME) in pseudophakic eyes after Descemet membrane endothelial keratoplasty (DMEK) performed after recent versus remote cataract surgery.

Methods: A retrospective chart review was performed of all consecutive eyes that underwent DMEK without concurrent cataract surgery at the University of Iowa between October 2012 and December 2014. The DMEK procedures were classified as staged if performed between 2 weeks and 6 months after cataract surgery and solitary if performed more than 6 months after cataract surgery.

A Simple and Reliable Technique to Orient Donor Corneal Tissue Using the Radial Width of the Surgical Limbus.

Purpose: To develop a method based on identification of the widest region of the surgical limbus that can yield quick and accurate orientation of excised human donor corneas.

Methods: Corneoscleral tissue from donors 49 to 75 years old was marked at the temporal sclera at the time of recovery. Digital images obtained from 20 corneas stored in viewing chambers, retroilluminated and viewed from the endothelial side, were used to quantify the per-degree radial width of the surgical limbus, defined as the distance from the scleral spur to clear cornea.

Regional assessment of energy-producing metabolic activity in the endothelium of donor corneas.

Purpose: We characterized mitochondrial respiration and glycolysis activity of human corneal endothelium, and compared metabolic activity between central and peripheral regions.

Methods: Endothelial keratoplasty-suitable corneas were obtained from donors aged 50 to 75 years. The endothelium-Descemet membrane complex (EDM) was isolated, and 3-mm punches were obtained from central and peripheral regions.

Physiological, anatomical, and behavioral changes after acoustic trauma in Drosophila melanogaster.

Noise-induced hearing loss (NIHL) is a growing health issue, with costly treatment and lost quality of life. Here we establish Drosophila melanogaster as an inexpensive, flexible, and powerful genetic model system for NIHL. We exposed flies to acoustic trauma and quantified physiological and anatomical effects.

The amnesiac gene is involved in the regulation of thermal nociception in Drosophila melanogaster.

Nociception is a mechanism fundamental to the ability of animals to avoid noxious stimuli capable of causing serious tissue damage. It has been established that in the fruit fly Drosophila melanogaster, the transient receptor potential (TRP) channel encoded by the painless gene (pain) is required for detecting thermal and mechanical noxious stimuli. Little is known, however, about other genetic components that control nociceptive behaviors in Drosophila.

Interspecific morphological variation in the wood-feeding cockroach, Cryptocercus (Dictyoptera: Cryptocercidae).

Appalachian species of Cryptocercus (Dictyoptera: Cryptocercidae) display considerable genetic variation, but little morphological variation has been reported. We employed light and scanning electron microscopy to investigate variation in male and female reproductive structures among four species of Cryptocercus. Our results indicated consistent, species-specific differences exist in the genitalia of the four species.

Identification of termite species and subspecies of the genus Zootermopsis using near-infrared reflectance spectroscopy.

Dampwood termites of the genus Zootermopsis (Isoptera: Termopsidae) are an abundant group of basal termites found in temperate forests of western North America. Three species are currently recognized in the genus and one of these species is subdivided into two subspecies. Although morphological and genetic characters are useful in differentiating among the three species and the two subspecies, respectively, only hydrocarbon analysis can enable differentiation both among the three species and the two subspecies.

Species-specific allozyme markers for Appalachian wood-feeding cockroaches (Dictyoptera: Cryptocercidae).

Members of the genus Cryptocercus are wood-feeding cockroaches that live in the temperate forests. Nine species are recognized in the genus worldwide: two in eastern Eurasia, two in China, and five in the United States. Within the United States, one species occurs in the Pacific Northwest and four occur in the Appalachian Mountains.