Corneal supply and the use of technology to reduce its demand: A review.

Recovery and access to end-of-life corneal tissue for corneal transplantation, training and research is globally maldistributed. The reasons for the maldistribution are complex and multifaceted, and not well defined or understood. Currently there are few solutions available to effectively address these issues. This review provides an overview of the system, key issues impacting recovery and allocation and emphasises how end-user ophthalmologists and researchers, with support from administrators and the wider sector, can assist in increasing access long-term through sustaining eye banks nationally and globally. We posit that prevention measures and improved surgical techniques, together with the development of novel therapies will play a significant role in reducing demand and enhance the equitable allocation of corneas.

Accelerometry predicts muscle ultrastructure and flight capabilities in a wild bird.

Muscle ultrastructure is closely linked with athletic performance in humans and lab animals, and presumably plays an important role in the movement ecology of wild animals. Movement is critical for wild animals to forage, escape predators and reproduce. However, little evidence directly links muscle condition to locomotion in the wild. We used GPS-accelerometers to examine flight behaviour and muscle biopsies to assess muscle ultrastructure in breeding black-legged kittiwakes (Rissa tridactyla). Biopsied kittiwakes showed similar reproductive success and subsequent over-winter survival to non-biopsied kittiwakes, suggesting that our study method did not greatly impact foraging ability. Muscle fibre diameter was negatively associated with wing beat frequency, likely because larger muscle fibres facilitate powered flight. The number of nuclei per fibre was positively associated with average air speed, likely because higher power output needed by faster-flying birds required plasticity for muscle fibre recruitment. These results suggest the potential for flight behaviour to predict muscle ultrastructure.

Seasonal muscle ultrastructure plasticity and resistance of muscle structural changes during temperature increases in resident black-capped chickadees and rock pigeons.

Resident birds in temperate zones respond to seasonally fluctuating temperatures by adjusting their physiology, such as changes in basal metabolic rate or peak metabolic rate during cold exposure, or altering their organ sizes, so as to match the thermogenic requirements of their current environment. Climate change is predicted to cause increases in the frequency of heat and cold wave events, which could increase the likelihood that birds will face an environmental mismatch. Here, we examined seasonality and the effects of acute and chronic heat shock to 33°C and subsequent recovery from heat shock on the ultrastructure of the superficial pectoralis muscle fiber diameter, myonuclear domain (MND) and capillary density in two temperate bird species of differing body mass, the black-capped chickadee (Poecile atricapillus) and the rock pigeon (Columba livia). We found that muscle fiber ultrastructure did not change with heat treatment. However, in black-capped chickadees, there was a significant increase in fiber diameter in spring phenotype birds compared with summer phenotype birds. In rock pigeons, we saw no differences in fiber diameter across seasons. Capillary density did not change as a function of fiber diameter in black-capped chickadees, but did change seasonally, as did MND. Across seasons, as fiber diameter decreased, capillary density increased in the pectoralis muscle of rock pigeons. For both species in this study, we found that as fiber diameter increased, so did MND. Our findings imply that these two temperate birds employ different muscular growth strategies that may be metabolically beneficial to each.

Medication adherence and activity patterns underlying uncontrolled hypertension: Assessment and recommendations by practicing pharmacists using digital health care.

OBJECTIVES: This report summarizes the first use of a digital health feedback system (DHFS) by practicing pharmacists to establish evidence-based blood pressure (BP) management recommendations. SETTING: Fifteen commercial pharmacies and 39 patients in the Isle of Wight participated. PRACTICE DESCRIPTION: The pharmacists were experienced in providing New Medicine Services to patients in their communities. PRACTICE INNOVATION: The pharmacists utilized a commercially available DHFS. The DHFS utilized FDA-cleared and CE-marked class 2 medical devices passively captured and shared information about medication-taking using an ingestible sensor, and daily patterns of rest, activity, and exercise using a wearable patch that incorporates an accelerometer. INTERVENTIONS: Pharmacists provided targeted counselling for BP management as guided by the digital information. EVALUATION: Blood pressure was measured serially, and patient and provider experiences with DHFS use were assessed using satisfaction surveys. RESULTS: The mean change in SBP over the 2-week evaluation period was -7.9 ± 22.1; mean change in DBP was -2.8 ± 12.9. A root cause for persistent hypertension was determined for all of these 34 patients: 68% had pharmaceutical resistance, and 32% had inadequate medication use. Specifically, 29% were found to be capable to achieving blood pressure control on their currently prescribed medications, 68% were found to have a need for additional pharmacological treatment, and 3% needed additional adherence support. Pharmacists found that the DHFD helped in targeting specific recommendations, and to create a collaborative experience with their patients. Patients found the experience to be positive and helpful. CONCLUSION: DHFS that provides confirmation of medication taking and objective measures of lifestyle patterns can help pharmacists to identify specific factors contributing to uncontrolled hypertension, to make evidence-based prescribing and lifestyle recommendations for achieving treatment goals, and to create a collaborative experience for patients in the management of their self-care.

Activation of the lectin pathway of complement in experimental human keratitis with Pseudomonas aeruginosa.

PURPOSE: Pseudomonas aeruginosa (P. aeruginosa) microbial keratitis (MK) is a sight-threatening disease. Previous animal studies have identified an important contribution of the complement system to the clearance of P. aeruginosa infection of the cornea. Mannose-binding lectin (MBL), a pattern recognition receptor of the lectin pathway of complement, has been implicated in the host defense against P. aeruginosa. However, studies addressing the role of the lectin pathway in P. aeruginosa MK are lacking. Hence, we sought to determine the activity of the lectin pathway in human MK caused by P. aeruginosa. METHODS: Primary human corneal epithelial cells (HCECs) from cadaveric donors were exposed to two different P. aeruginosa strains. Gene expression of interleukin (IL)-6, IL-8, MBL, and other complement proteins was determined by reverse transcription-polymerase chain reaction (RT-PCR) and MBL synthesis by enzyme-linked immunosorbent assay and intracellular flow cytometry. RESULTS: MBL gene expression was not detected in unchallenged HCECs. Exposure of HCECs to P. aeruginosa resulted in rapid induction of the transcriptional expression of MBL, IL-6, and IL-8. In addition, expression of several complement proteins of the classical and lectin pathways, but not the alternative pathway, were upregulated after 5 h of challenge, including MBL-associated serine protease 1. However, MBL protein secretion was not detectable 18 h after challenge with P. aeruginosa. CONCLUSIONS: MK due to P. aeruginosa triggers activation of MBL and the lectin pathway of complement. However, the physiologic relevance of this finding is unclear, as corresponding MBL oligomer production was not observed.

Single nuclei transcriptomics of the in situ human limbal stem cell niche.

The corneal epithelium acts as a barrier to pathogens entering the eye; corneal epithelial cells are continuously renewed by uni-potent, quiescent limbal stem cells (LSCs) located at the limbus, where the cornea transitions to conjunctiva. There has yet to be a consensus on LSC markers and their transcriptome profile is not fully understood, which may be due to using cadaveric tissue without an intact stem cell niche for transcriptomics. In this study, we addressed this problem by using single nuclei RNA sequencing (snRNAseq) on healthy human limbal tissue that was immediately snap-frozen after excision from patients undergoing cataract surgery. We identified the quiescent LSCs as a sub-population of corneal epithelial cells with a low level of total transcript counts. Moreover, TP63, KRT15, CXCL14, and ITGß4 were found to be highly expressed in LSCs and transiently amplifying cells (TACs), which constitute the corneal epithelial progenitor populations at the limbus. The surface markers SLC6A6 and ITGß4 could be used to enrich human corneal epithelial cell progenitors, which were also found to specifically express the putative limbal progenitor cell markers MMP10 and AC093496.1.

Evaluation of a Virtual Tai Chi Program for Older Veterans at Risk of Loneliness or Physical Deconditioning: A Quality Improvement Project.

This Quality Improvement project evaluated the implementation of a virtual Tai Chi program for older Veterans (OVs) at risk of loneliness and/or physical deconditioning. A 12-week Tai Chi course was conducted virtually at three Veterans Affairs sites using VA Video Connect (VVC). Changes in physical function based on the 30-Second Chair Stand (30CST) and loneliness based on the De Jong Gierveld Loneliness Scale (DJGS) were measured, as were the OVs' satisfaction and adherence. Of 109 OVs who enrolled, 74 completed the program with a mean attendance rate of 84%. Completers demonstrated a statistically significant improvement in the 30CST, and those who were moderately or severely lonely at baseline saw a statistically significant improvement in the DJGS. Course evaluations were generally very positive. Results suggest that a virtual Tai Chi program is an effective and very satisfying intervention for OVs at risk of loneliness or physical deconditioning.

Exploring single-cell RNA sequencing as a decision-making tool in the clinical management of Fuchs' endothelial corneal dystrophy.

Single-cell RNA sequencing (scRNA-seq) has enabled the identification of novel gene signatures and cell heterogeneity in numerous tissues and diseases. Here we review the use of this technology for Fuchs' Endothelial Corneal Dystrophy (FECD). FECD is the most common indication for corneal endothelial transplantation worldwide. FECD is challenging to manage because it is genetically heterogenous, can be autosomal dominant or sporadic, and progress at different rates. Single-cell RNA sequencing has enabled the discovery of several FECD subtypes, each with associated gene signatures, and cell heterogeneity. Current FECD treatments are mainly surgical, with various Rho kinase (ROCK) inhibitors used to promote endothelial cell metabolism and proliferation following surgery. A range of emerging therapies for FECD including cell therapies, gene therapies, tissue engineered scaffolds, and pharmaceuticals are in preclinical and clinical trials. Unlike conventional disease management methods based on clinical presentations and family history, targeting FECD using scRNA-seq based precision-medicine has the potential to pinpoint the disease subtypes, mechanisms, stages, severities, and help clinicians in making the best decision for surgeries and the applications of therapeutics. In this review, we first discuss the feasibility and potential of using scRNA-seq in clinical diagnostics for FECD, highlight advances from the latest clinical treatments and emerging therapies for FECD, integrate scRNA-seq results and clinical notes from our FECD patients and discuss the potential of applying alternative therapies to manage these cases clinically.

Current status and future prospects for cultured limbal tissue transplants in Australia and New Zealand.

Cultured limbal tissue transplants have become widely used over the last decade as a treatment for limbal stem cell deficiency (LSCD). While the number of patients afflicted with LSCD in Australia and New Zealand is considered to be relatively low, the impact of this disease on quality of life is so severe that the potential efficacy of cultured transplants has necessitated investigation. We presently review the basic biology and experimental strategies associated with the use of cultured limbal tissue transplants in Australia and New Zealand. In doing so, we aim to encourage informed discussion on the issues required to advance the use of cultured limbal transplants in Australia and New Zealand. Moreover, we propose that a collaborative network could be established to maintain access to the technology in conjunction with a number of other existing and emerging treatments for eye diseases.

Identifying probable dementia in undiagnosed Black and White Americans using machine learning in Veterans Health Administration electronic health records.

The application of machine learning (ML) tools in electronic health records (EHRs) can help reduce the underdiagnosis of dementia, but models that are not designed to reflect minority population may perpetuate that underdiagnosis. To address the underdiagnosis of dementia in both Black Americans (BAs) and white Americans (WAs), we sought to develop and validate ML models that assign race-specific risk scores. These scores were used to identify undiagnosed dementia in BA and WA Veterans in EHRs. More specifically, risk scores were generated separately for BAs (n=10K) and WAs (n=10K) in training samples of cases and controls by performing ML, equivalence mapping, topic modeling, and a support vector-machine (SVM) in structured and unstructured EHR data. Scores were validated via blinded manual chart reviews (n=1.2K) of controls from a separate sample (n=20K). AUCs and negative and positive predictive values (NPVs and PPVs) were calculated to evaluate the models. There was a strong positive relationship between SVM-generated risk scores and undiagnosed dementia. BAs were more likely than WAs to have undiagnosed dementia per chart review, both overall (15.3% vs 9.5%) and among Veterans with >90th percentile cutoff scores (25.6% vs 15.3%). With chart reviews as the reference standard and varied cutoff scores, the BA model performed slightly better than the WA model (AUC=0.86 with NPV=0.98 and PPV=0.26 at >90th percentile cutoff vs AUC=0.77 with NPV=0.98 and PPV=0.15 at >90th). The AUCs, NPVs, and PPVs suggest that race-specific ML models can assist in the identification of undiagnosed dementia, particularly in BAs. Future studies should investigate implementing EHR-based risk scores in clinics that serve both BA and WA Veterans.

Geographical Inequality on Cataract Surgery Uptake in 200,000 Australians: Findings from the "45 and Up Study".

Using a geographical information system (GIS), we investigated the spatiotemporal evolution of a cataract surgery service and its association with socioeconomic factors and private insurance, based on 10-year real-world medical claim data in an Australian population. The data collected cover a decade (2007-2016) from the "45 and Up Study". A total of 234,201 participants within the cataract surgery service were grouped into 88 Statistical Area Level 3 (SA3s) according to their residential postcodes in New South Wales Australia. We analyzed the spatiotemporal variations and geographical distribution inequality in cataract surgery incidence and its respect to socioeconomic status (SES) and private health insurance coverage by Spearman correlation analysis and Moran's I test. Then these variations were intuitive displayed by six-quartile maps and a local indicator of spatial association (LISA) maps based on GIS. The average cumulative age-gender-standardized of the incidence of cataract surgery (ICS) was 8.85% (95% CI, 5.33-15.6). Spatial variation was significant (univariate Moran's I = 0.45, P = 0.001) with incidence gradually decreasing from the coastal regions to the north-western inland regions, suggesting inequality in the cataract surgery service across the state of New South Wales. Notably, clustering of the low incidence areas had gradually disappeared over the decade, suggesting that the cataract surgery service has improved over time. Low scores on the "index of socioeconomic disadvantages" (IRSD) and high private health insurance coverage were significantly associated with a higher incidence of cataract surgery (bivariate Moran's I = -0.13 and 0.23, P < 0.01; Spearman correlation r = 0.25 and -0.25, P = 0.02), which is displayed on the map visually and obviously. Spatiotemporal variations in the incidence of cataract surgery are significant, but the low incidence area had gradually disappeared over time. High socioeconomic status and private insurance contribute to a higher incidence of cataract surgery in Australia.

Ocular Tissue for Research in Australia: Strategies for Potential Research Utility of Surplus and Transplant-Ineligible Deceased Donations.

A 2016 Price Waterhouse Cooper Report, commissioned by the Australian Commonwealth Government's Organ and Tissue Authority, indicated that Australia had been meeting its human ocular tissue for transplant needs. It further suggested that Australia should consider exportation as a management strategy for excess tissue. Although we do not seek to discuss how the Price Waterhouse Cooper Report determined that need was being met, nor the potential value of exportation in this article, we propose that Ocular Tissue for Research (OTR), and particularly identification of donors for research, and timely access to fresh domestic tissue, be considered as an alternate or simultaneous surplus management strategy. A robust OTR system could provide long-term domestic support and investment into research and development of therapies in Australia. Such a system would also provide a meaningful donation option for those otherwise unable to donate for transplant. This article attempts to document, for the first time to our knowledge, the current recovery and distribution processes of deceased OTR in Australia. It maps the process steps, identifies the stakeholders and needs, discusses the limitations and barriers, and proposes key policy and practice reform strategies that may assist in improving access to OTR. Translational Relevance: To improve and increase access to human ocular tissue for research, and in turn, advance vision science and clinical application.

Muscle fiber structure in an aging long-lived seabird, the black-legged kittiwake (Rissa tridactyla).

Many long-lived animals do not appear to show classic signs of aging, perhaps because they show negligible senescence until dying from "catastrophic" mortality. Muscle senescence is seldom examined in wild animals, yet decline in muscle function is one of the first signs of aging in many lab animals and humans. Seabirds are an excellent study system for physiological implications of aging because they are long-lived animals that actively forage and reproduce in the wild. Here, we examined linkages between pectoralis muscle fiber structure and age in black-legged kittiwakes (Rissa tridactyla). Pectoralis muscle is the largest organ complex in birds, and responsible for flight and shivering. We obtained and fixed biopsies from wild black-legged kittiwakes of known age. We then measured muscle fiber diameter, myonuclear domain and capillaries per fiber area among birds of differing ages. All muscle parameters were independent of age. Number of nuclei per mm of fiber showed a positive correlation with muscle fiber cross-sectional area, and myonuclear domain increased with muscle fiber diameter. Thus, as muscle fibers increased in size, they may not have recruited satellite cells, increasing the protein turnover load per nuclei. We conclude that senescence in a long-lived bird with an active lifestyle, does not entail mammalian-like changes in muscle structure.

Force control strategies while driving electric powered wheelchairs with isometric and movement-sensing joysticks.

Innovations to control interfaces for electric powered wheelchairs (EPWs) could benefit 220000 current users and over 125000 individuals who desire mobility but cannot use a conventional motion sensing joystick (MSJ). We developed a digital isometric joystick (IJ) with sophisticated signal processing and two control functions. In a prior study, subjects' driving accuracy with our IJ was comparable to using an MSJ. However, we observed subjects using excessive force on the IJ possibly because its rigid post provides no positional feedback. Thus, this paper examines the time-series data recorded in the previous study to characterize subjects' force control strategies since weakness is a concern. Eleven EPW users with upper limb impairments drove an EPW using an IJ with two different control functions and an MSJ in a Fitts' law paradigm. Subjects relied upon positional feedback from the MSJ and used appropriate force. In contrast, subjects using the IJ with either control function applied significantly higher force than necessary (p < 0.0001 and p = 0.0058). Using higher average force was correlated with quicker trial times but not associated with accuracy. Lack of positional feedback may result in use of excess isometric force. Modifying control functions, adjusting gain, or providing additional training or feedback might address this problem.

Transforming Growth Factor ß1-Induced NADPH Oxidase-4 Expression and Fibrotic Response in Conjunctival Fibroblasts.

Purpose: Fibrotic scarring after ocular surgeries and chemical burn injuries can impede clarity of the cornea and cause vision impairment. Transforming growth factor ß (TGFß) signaling pathway is known to mediate fibrotic scarring, and NADPH oxidase-derived reactive oxygen species has been shown to be an effector molecule that facilitates TGFß1-mediated responses. The present study explores the expression profile and functional importance of NADPH oxidase (Nox) in conjunctival fibroblasts. In addition, the effect of curcumin on the TGFß1-induced NADPH oxidase expression and collagen synthesis was also investigated. Methods: The mRNA expression of Nox isoforms in rabbit conjunctival fibroblasts was measured by real-time PCR. The production of hydrogen peroxide (H2O2) and total collagen by these cells was measured by Amplex Red assay and Picro-Sirius red assay, respectively. Nox4 was knocked down by adenovirus-mediated siRNA targeting Nox4 (Adv-Nox4i). Results: We describe for the first time that conjunctival fibroblasts express mRNA encoding for Nox2, Nox3, Nox4, and Nox5. TGFß1 was found to induce Nox4 mRNA expression and total collagen release by these cells (P < 0.05; n = 4), and both responses are blocked by Smad3 inhibitor SIS3. Suppressing Nox4 gene transcription with Adv-Nox4i completely attenuated TGFß1-stimulated H2O2 release and collagen production by conjunctival fibroblasts (P < 0.05; n = 4-6). Similarly, curcumin also inhibited TGFß1-induced Smad3 phosphorylation, Nox4-derived H2O2 production, and total collagen synthesis by conjunctival fibroblasts (P < 0.05; n = 4-6). Conclusions: The present study suggests that TGFß1-mediated production of collagen by conjunctival fibroblasts involves Nox4-derived H2O2 pathway and this effect of Nox4 is abrogated by curcumin. This mechanism might be exploited to prevent fibrotic scarring after surgeries and chemical burn injuries in the eye.

Preliminary evaluation of variable compliance joystick for people with multiple sclerosis.

Upper-limb fatigue is a common problem that may restrict people with multiple sclerosis (MS) from using their electric powered wheelchair effectively and for a long period of time. The objective of this research is to evaluate whether participants with MS can drive better using a variable compliance joystick (VCJ) and customizable algorithms than with a conventional wheelchair joystick. Eleven participants were randomly assigned to one of two groups. The groups used either the VCJ in compliant or noncompliant isometric mode and a standard algorithm, personally fitted algorithm, or personally fitted algorithm with fatigue adaptation running in the background in order to complete virtual wheelchair driving tasks. Participants with MS showed better driving performance metrics while using the customized algorithms than while using the standard algorithm with the VCJ. Fatigue adaptation algorithms are especially beneficial in improving overall task performance while using the VCJ in isometric mode. The VCJ, along with the personally fitted algorithms and fatigue adaptation algorithms, has the potential to be an effective input interface for wheelchairs.

Plasma polymer-coated contact lenses for the culture and transfer of corneal epithelial cells in the treatment of limbal stem cell deficiency.

Extensive damage to the limbal region of the cornea leads to a severe form of corneal blindness termed as limbal stem cell deficiency (LSCD). Whereas most cases of corneal opacity can be treated with full thickness corneal transplants, LSCD requires stem cell transplantation for successful ocular surface reconstruction. Current treatments for LSCD using limbal stem cell transplantation involve the use of murine NIH 3T3 cells and human amniotic membranes as culture substrates, which pose the threat of transmission of animal-derived pathogens and donor tissue-derived cryptic infections. In this study, we aimed to produce surface modified therapeutic contact lenses for the culture and delivery of corneal epithelial cells for the treatment of LSCD. This approach avoids the possibility of suture-related complications and is completely synthetic. We used plasma polymerization to deposit acid functional groups onto the lenses at various concentrations. Each surface was tested for its suitability to promote corneal epithelial cell adhesion, proliferation, retention of stem cells, and differentiation and found that acid-based chemistries promoted better cell adhesion and proliferation. We also found that the lenses coated with a higher percentage of acid functional groups resulted in a higher number of cells transferred onto the corneal wound bed in rabbit models of LSCD. Immunohistochemistry of the recipient cornea confirmed the presence of autologous, transplanted 5-bromo-2'-deoxyuridine (BrdU)-labeled cells. Hematoxylin staining has also revealed the presence of a stratified epithelium at 26 days post-transplantation. This study provides the first evidence for in vivo transfer and survival of cells transplanted from a contact lens to the wounded corneal surface. It also proposes the possibility of using plasma polymer-coated contact lenses with high acid functional groups as substrates for the culture and transfer of limbal cells in the treatment of LSCD.

Acrylic acid surface-modified contact lens for the culture of limbal stem cells.

Surface treatment to a biomaterial surface has been shown to modify and help cell growth. Our aim was to determine the best surface-modified system for the treatment of limbal stem cell deficiency (LSCD), which would facilitate expansion of autologous limbal epithelial cells, while maintaining cultivated epithelial cells in a less differentiated state. Commercially available contact lenses (CLs) were variously surface modified by plasma polymerization with ratios of acrylic acid to octadiene tested at 100% acrylic acid, 50:50% acrylic acid:octadiene, and 100% octadiene to produce high-, mid-, and no-acid. X-ray photoelectron spectroscopy was used to analyze the chemical composition of the plasma polymer deposited layer. Limbal explants cultured on high acid-modified CLs outgrew more cells. Immunofluorescence and RT2-PCR array results indicated that a higher acrylic acid content can also help maintain progenitor cells during ex vivo expansion of epithelial cells. This study provides the first evidence for the ability of high acid-modified CLs to preserve the stemness and to be used as substrates for the culture of limbal cells in the treatment of LSCD.

Biodegradable and biocompatible poly(ethylene glycol)-based hydrogel films for the regeneration of corneal endothelium.

Corneal endothelial cells (CECs) are responsible for maintaining the transparency of the human cornea. Loss of CECs results in blindness, requiring corneal transplantation. In this study, fabrication of biocompatible and biodegradable poly(ethylene glycol) (PEG)-based hydrogel films (PHFs) for the regeneration and transplantation of CECs is described. The 50-µm thin hydrogel films have similar or greater tensile strengths to human corneal tissue. Light transmission studies reveal that the films are >98% optically transparent, while in vitro degradation studies demonstrate their biodegradation characteristics. Cell culture studies demonstrate the regeneration of sheep corneal endothelium on the PHFs. Although sheep CECs do not regenerate in vivo, these cells proliferate on the films with natural morphology and become 100% confluent within 7 d. Implantation of the PHFs into live sheep corneas demonstrates the robustness of the films for surgical purposes. Regular slit lamp examinations and histology of the cornea after 28 d following surgery reveal minimal inflammatory responses and no toxicity, indicating that the films are benign. The results of this study suggest that PHFs are excellent candidates as platforms for the regeneration and transplantation of CECs as a result of their favorable biocompatibility, degradability, mechanical, and optical properties.