Adiponectin Reduces Glomerular Endothelial Glycocalyx Disruption and Restores Glomerular Barrier Function in a Mouse Model of Type 2 Diabetes.

Adiponectin has vascular anti-inflammatory and protective effects. Although adiponectin protects against the development of albuminuria, historically, the focus has been on podocyte protection within the glomerular filtration barrier (GFB). The first barrier to albumin in the GFB is the endothelial glycocalyx (eGlx), a surface gel-like barrier covering glomerular endothelial cells (GEnCs). In diabetes, eGlx dysfunction occurs before podocyte damage; hence, we hypothesized that adiponectin could protect from eGlx damage to prevent early vascular damage in diabetic kidney disease (DKD). Globular adiponectin (gAd) activated AMPK signaling in human GEnCs through AdipoR1. It significantly reduced eGlx shedding and the tumor necrosis factor-α (TNF-α)-mediated increase in syndecan-4 (SDC4) and MMP2 mRNA expression in GEnCs in vitro. It protected against increased TNF-α mRNA expression in glomeruli isolated from db/db mice and against expression of genes associated with glycocalyx shedding (namely, SDC4, MMP2, and MMP9). In addition, gAd protected against increased glomerular albumin permeability (Ps'alb) in glomeruli isolated from db/db mice when administered intraperitoneally and when applied directly to glomeruli (ex vivo). Ps'alb was inversely correlated with eGlx depth in vivo. In summary, adiponectin restored eGlx depth, which was correlated with improved glomerular barrier function, in diabetes.

Codesign of Lynch ChoicesTM : Using implementation science to create a clinically deliverable patient decision support website to transform cancer genetics care pathways.

BACKGROUND: Resources including Patient Decision Aids (PtDA) are useful and valued by patients and clinicians to provide information and complement shared decision-making. Despite their promise, few PtDA exist for patients with genetic cancer susceptibility facing difficult decisions about risk management. We aimed to fill this gap, partnering with patients to codesign Lynch ChoicesTM , a PtDA website for families with Lynch Syndrome. In addition to a Patient Reference Panel, we purposively invited an international stakeholder panel including charities, public bodies, clinical and academic experts. Implementation strategies and frameworks were employed to optimise translation of research findings to improve care. METHODS: Patient/stakeholder suggestions were incorporated in a transparent Table of Changes and prioritised using the Person-Based Approach throughout planning and codesign of Lynch ChoicesTM . An interactive stakeholder meeting was convened to identify barriers and facilitators to clinical implementation of the PtDA. RESULTS: Patient and stakeholder partnerships drove the direction of the research throughout codesign, resulting in several iterative refinements to the PtDA prior to roll out including the addition of illustrations/videos, clearer presentation of cancer risks and increased accessibility for lower literacy. Barriers and facilitators identified from stakeholders were used to create an implementation process map. CONCLUSIONS: Creating an effective, engaging PtDA is not enough. Systematic uptake in real world clinical practice, with its resource limitations, is needed to optimise benefit to patients and clinicians. Assessment of speed and breadth of dissemination and usage will be collected to further evidence the benefit of embedding implementation science methods from the outset to translate research findings into clinical practice.

Heparanase inhibition as a systemic approach to protect the endothelial glycocalyx and prevent microvascular complications in diabetes.

BACKGROUND: Diabetes mellitus is a chronic disease which is detrimental to cardiovascular health, often leading to secondary microvascular complications, with huge global health implications. Therapeutic interventions that can be applied to multiple vascular beds are urgently needed. Diabetic retinopathy (DR) and diabetic kidney disease (DKD) are characterised by early microvascular permeability changes which, if left untreated, lead to visual impairment and renal failure, respectively. The heparan sulphate cleaving enzyme, heparanase, has previously been shown to contribute to diabetic microvascular complications, but the common underlying mechanism which results in microvascular dysfunction in conditions such as DR and DKD has not been determined. METHODS: In this study, two mouse models of heparan sulphate depletion (enzymatic removal and genetic ablation by endothelial specific Exotosin-1 knock down) were utilized to investigate the impact of endothelial cell surface (i.e., endothelial glycocalyx) heparan sulphate loss on microvascular barrier function. Endothelial glycocalyx changes were measured using fluorescence microscopy or transmission electron microscopy. To measure the impact on barrier function, we used sodium fluorescein angiography in the eye and a glomerular albumin permeability assay in the kidney. A type 2 diabetic (T2D, db/db) mouse model was used to determine the therapeutic potential of preventing heparan sulphate damage using treatment with a novel heparanase inhibitor, OVZ/HS-1638. Endothelial glycocalyx changes were measured as above, and microvascular barrier function assessed by albumin extravasation in the eye and a glomerular permeability assay in the kidney. RESULTS: In both models of heparan sulphate depletion, endothelial glycocalyx depth was reduced and retinal solute flux and glomerular albumin permeability was increased. T2D mice treated with OVZ/HS-1638 had improved endothelial glycocalyx measurements compared to vehicle treated T2D mice and were simultaneously protected from microvascular permeability changes associated with DR and DKD. CONCLUSION: We demonstrate that endothelial glycocalyx heparan sulphate plays a common mechanistic role in microvascular barrier function in the eye and kidney. Protecting the endothelial glycocalyx damage in diabetes, using the novel heparanase inhibitor OVZ/HS-1638, effectively prevents microvascular permeability changes associated with DR and DKD, demonstrating a novel systemic approach to address diabetic microvascular complications.

A small molecule chaperone rescues keratin-8 mediated trafficking of misfolded podocin to correct genetic Nephrotic Syndrome.

Podocin is a key membrane scaffolding protein of the kidney podocyte essential for intact glomerular filtration. Mutations in NPHS2, the podocin-encoding gene, represent the commonest form of inherited nephrotic syndrome (NS), with early, intractable kidney failure. The most frequent podocin gene mutation in European children is R138Q, causing retention of the misfolded protein in the endoplasmic reticulum. Here, we provide evidence that podocin R138Q (but not wild-type podocin) complexes with the intermediate filament protein keratin 8 (K8) thereby preventing its correct trafficking to the plasma membrane. We have also identified a small molecule (c407), a compound that corrects the Cystic Fibrosis Transmembrane Conductance Regulator protein defect, that interrupts this complex and rescues mutant protein mistrafficking. This results in both the correct localization of podocin at the plasma membrane and functional rescue in both human patient R138Q mutant podocyte cell lines, and in a mouse inducible knock-in model of the R138Q mutation. Importantly, complete rescue of proteinuria and histological changes was seen when c407 was administered both via osmotic minipumps or delivered orally prior to induction of disease or crucially via osmotic minipump two weeks after disease induction. Thus, our data constitute a therapeutic option for patients with NS bearing a podocin mutation, with implications for other misfolding protein disorders. Further studies are necessary to confirm our findings.

Communicating neurocognitive impacts of childhood cancer: Engaging stakeholders to identify research priorities.

OBJECTIVE: Supporting childhood cancer survivors with neurocognitive late effects is critical and requires additional attention in the research arena. This convening project's aim was to engage parents, healthcare providers, and education stakeholders in order to identify research priorities regarding patient/family-provider communication about neurocognitive impacts associated with childhood cancer. METHODS: Specific components of the Stakeholder Engagement in quEstion Development (SEED) method were combined with an online e-Delphi consensus building approach. Multiple modalities were utilized for engagement including in-person/hybrid meetings, email/Zoom/call communications, targeted-asynchronous learning activities by stakeholders, iterative surveys, and hands-on conceptual modeling. RESULTS: Twenty-four (parents n = 10, educators n = 5, healthcare providers n = 9) participated in the year-long project, generating 8 research questions in the stakeholder priority domains of training families/caregiver, access of neuropsychological assessment, tools to facilitate communication and training medical providers. CONCLUSIONS: This paper illustrates a successful stakeholder convening process using multi-modal engagement to establish research priorities. The resulting questions can be utilized to guide research projects that will fill gaps to providing optimal care to children with neurocognitive late effects. PRACTICE IMPLICATIONS: This process can be used as a template for tackling other healthcare issues that span across disciplines and domains, where stakeholders have rare opportunities to collaborate.

Projected health and economic outcomes of extending public funding of pharmacy services to include administration of Pneu23 and Td/Tdap immunizations by pharmacy practitioners in New Brunswick.

Background: Although legislation permits New Brunswick pharmacy professionals to administer a wide range of immunizations, public funding for these services is currently limited to immunizations against influenza and COVID-19 and was recently extended to include pneumococcal immunization (Pneu23) in individuals aged 65 years or older. We used administrative data to project health and economic outcomes associated with the current Pneu23 program and with extension of public funding to include: 1) younger adults aged 19 years or older in the Pneu23 program, and 2) tetanus boosters (Td/Tdap). Methods: Two model scenarios were compared: a Physician-Only model in which physicians remain the only practitioners to administer publicly funded Pneu23 and Td/Tdap, and a Blended model in which this service is also provided by pharmacy professionals. Immunization rates by practitioner type were projected based on physician billing data accessed via the New Brunswick Institute for Research, Data and Training in conjunction with trends observed with influenza immunization by pharmacists. These projections were used along with published data to estimate health and economic outcomes under each model. Results: Public funding of Pneu23 (65+), Pneu23 (19+) and Td/Tdap (19+) administration by pharmacy professionals is projected to yield increased immunization rates and physician time savings compared with the Physician-Only model. Public funding of Pneu23 and Td/Tdap administration by pharmacy professionals in those aged ≥19 years would result in cost savings, owing primarily to productivity losses avoided in the working age population. Discussion: Increased immunization rates, physician time savings and cost savings may be realized if public funding were extended to include administration of Pneu23 in younger adults and Td/Tdap, by pharmacy practitioners.

The unique structural and functional characteristics of glomerular endothelial cell fenestrations and their potential as a therapeutic target in kidney disease.

Glomerular endothelial cell (GEnC) fenestrations are a critical component of the glomerular filtration barrier. Their unique nondiaphragmed structure is key to their function in glomerular hydraulic permeability, and their aberration in disease can contribute to loss of glomerular filtration function. This review provides a comprehensive update of current understanding of the regulation and biogenesis of fenestrae. We consider diseases in which GEnC fenestration loss is recognized or may play a role and discuss methods with potential to facilitate the study of these critical structures. Literature is drawn from GEnCs as well as other fenestrated cell types such as liver sinusoidal endothelial cells that most closely parallel GEnCs.

Feasibility and Acceptability of an Overdose Prevention Intervention Delivered by Community Pharmacists for Patients Prescribed Opioids for Chronic Non-Cancer Pain.

There have been increases in prescriptions of high strength opioids for chronic non-cancer pain (CNCP), but CNCP patients perceive themselves as being at low risk of opioid overdose and generally have limited overdose awareness. This study examined how an overdose prevention intervention (opioid safety education, naloxone training, and take-home naloxone (THN)) delivered by community pharmacists for patients prescribed high-strength opioids for CNCP would work in practice in Scotland. Twelve patients received the intervention. CNCP patients and Community Pharmacists were interviewed about their experiences of the intervention and perceptions of its acceptability and feasibility. CNCP patients did not initially perceive themselves as being at risk of overdose but, through the intervention, developed insight into opioid-related risk and the value of naloxone. Pharmacists also identified patients' low risk perceptions and low overdose awareness. While pharmacists had positive attitudes towards the intervention, they outlined challenges in delivering it under time and resource pressures and during the COVID-19 pandemic. Overdose prevention interventions are required in the CNCP population as this group has elevated risk factors for overdose but are commonly overlooked. Customised overdose prevention interventions for CNCP patients attend to gaps in overdose awareness and risk perceptions in this population.

Podocyte protease activated receptor 1 stimulation in mice produces focal segmental glomerulosclerosis mirroring human disease signaling events.

About 30% of patients who have a kidney transplant with underlying nephrotic syndrome (NS) experience rapid relapse of disease in their new graft. This is speculated to be due to a host-derived circulating factor acting on podocytes, the target cells in the kidney, leading to focal segmental glomerulosclerosis (FSGS). Our previous work suggests that podocyte membrane protease receptor 1 (PAR-1) is activated by a circulating factor in relapsing FSGS. Here, the role of PAR-1 was studied in human podocytes in vitro, and using a mouse model with developmental or inducible expression of podocyte-specific constitutively active PAR-1, and using biopsies from patients with nephrotic syndrome. In vitro podocyte PAR-1 activation caused a pro-migratory phenotype with phosphorylation of the kinase JNK, VASP protein and docking protein Paxillin. This signaling was mirrored in podocytes exposed to patient relapse-derived NS plasma and in patient disease biopsies. Both developmental and inducible activation of transgenic PAR-1 (NPHS2 Cre PAR-1Active+/-) caused early severe nephrotic syndrome, FSGS, kidney failure and, in the developmental model, premature death. We found that the non-selective cation channel protein TRPC6 could be a key modulator of PAR-1 signaling and TRPC6 knockout in our mouse model significantly improved proteinuria and extended lifespan. Thus, our work implicates podocyte PAR-1 activation as a key initiator of human NS circulating factor and that the PAR-1 signaling effects were partly modulated through TRPC6.

Mediators of Social Acceptance Among Emerging Adult Survivors of Childhood Cancer.

Purpose: Examine associations of social developmental factors (e.g., peer/parent social attachment, romantic relationships) and perceptions of social acceptance among emerging adult survivors of childhood cancer. Methods: A cross-sectional, within-group design was used. Questionnaires included the Multidimensional Body-Self Relations Questionnaire, Inventory of Parent and Peer Attachment, Adolescent Social Self-Efficacy Scale, Personal Evaluation Inventory, Self-Perception Profile for Adolescents, and demographics. Correlations were utilized to determine associations between general demographic, cancer-specific, and the psychosocial outcome variables. Peer and romantic relationship self-efficacy were assessed as potential mediators of social acceptance in three mediation models. Relationships between perceived physical attractiveness, peer attachment, parental attachment, and social acceptance were assessed. Results: Data were collected from N = 52 adult participants (Mage = 21.38 years, standard deviation = 3.11 years) diagnosed with cancer as a child. The first mediation model demonstrated a significant direct effect of perceived physical attraction on perceived social acceptance and retained significance after adjusting for indirect effects of the mediators. The second model demonstrated a significant direct effect of peer attachment on perceived social acceptance; however, significance was not retained after adjusting for peer self-efficacy, suggesting the relationship is partially mediated by peer relationship self-efficacy. The third model demonstrated a significant direct effect of parent attachment on perceived social acceptance; however, significance was not retained after adjusting for peer self-efficacy, suggesting the relationship is partially mediated by peer self-efficacy. Conclusion: Relationships between social developmental factors (e.g., parental and peer attachment) and perceived social acceptance are likely mediated by peer relationship self-efficacy in emerging adult survivors of childhood cancer.

Mineralocorticoid receptor antagonism in diabetes reduces albuminuria by preserving the glomerular endothelial glycocalyx.

The glomerular endothelial glycocalyx (GEnGlx) forms the first part of the glomerular filtration barrier. Previously, we showed that mineralocorticoid receptor (MR) activation caused GEnGlx damage and albuminuria. In this study, we investigated whether MR antagonism could limit albuminuria in diabetes and studied the site of action. Streptozotocin-induced diabetic Wistar rats developed albuminuria, increased glomerular albumin permeability (Ps'alb), and increased glomerular matrix metalloproteinase (MMP) activity with corresponding GEnGlx loss. MR antagonism prevented albuminuria progression, restored Ps'alb, preserved GEnGlx, and reduced MMP activity. Enzymatic degradation of the GEnGlx negated the benefits of MR antagonism, confirming their dependence on GEnGlx integrity. Exposing human glomerular endothelial cells (GEnC) to diabetic conditions in vitro increased MMPs and caused glycocalyx damage. Amelioration of these effects confirmed a direct effect of MR antagonism on GEnC. To confirm relevance to human disease, we used a potentially novel confocal imaging method to show loss of GEnGlx in renal biopsy specimens from patients with diabetic nephropathy (DN). In addition, patients with DN randomized to receive an MR antagonist had reduced urinary MMP2 activity and albuminuria compared with placebo and baseline levels. Taken together, our work suggests that MR antagonists reduce MMP activity and thereby preserve GEnGlx, resulting in reduced glomerular permeability and albuminuria in diabetes.

Patient, family members and community pharmacists' views of a proposed overdose prevention intervention delivered in community pharmacies for patients prescribed high-strength opioids for chronic non-cancer pain: An explorative intervention development study.

INTRODUCTION: Despite opioid prescribing for chronic non-cancer pain (CNCP) having limited therapeutic benefits, recent evidence indicates significant increases in the prescribing of high-strength opioids for individuals with CNCP. Patients prescribed opioids for CNCP have overdose risk factors but generally have low opioid overdose awareness and low perceptions of risk related to prescribed opioids. Currently, there are few bespoke overdose prevention resources for this group. METHODS: This qualitative study investigated views on a naloxone intervention for people prescribed high-strength opioids for CNCP delivered via community pharmacies. The intervention included overdose risk awareness and naloxone training and provision. Interviews were conducted with eight patients, four family members and two community pharmacists. Participants were convenience sampled and recruited through networks within the Scottish pain community. The Framework approach was used to analyse findings. RESULTS: All participants had positive attitudes towards the intervention, but patients and family members considered risk of overdose to be very low. Three themes were identified: potential advantages of the intervention; potential barriers to the intervention; and additional suggestions and feedback about the intervention. Advantages included the intervention providing essential overdose information for CNCP patients. Barriers included resource and time pressures within community pharmacies. DISCUSSION AND CONCLUSION: While patients had low overdose knowledge and did not see themselves as being at risk of opioid overdose, they were receptive to naloxone use and positive about the proposed intervention. A feasibility trial is merited to further investigate how the intervention would be experienced within community pharmacy settings.

Dietary similarity among jaguars (Panthera onca) in a high-density population.

Prey remains found in carnivore scats provide generalised dietary profiles of sampled populations. The profile may be biased if individual diets differ and some individuals are over- or under-represented in the sample. Quantifying individual contributions allows us to recognise these potential biases and better interpret generalised profiles. Knowing the dietary differences or similarity between individuals can help us to understand selection pressures and identify drivers of distribution and abundance. Using the results of individual faecal genotyping, we re-interpreted our previously-published generalised dietary profile of an elusive, neotropical felid, the jaguar (Panthera onca; Foster et al. (2010)). We quantified individual sample sizes, assessed whether the generalised profile was influenced by the inclusion of scats originating from the same individual and prey carcass (pseudo-replication), and quantified the distribution of prey species among individuals. From an original sample of 322 jaguar scats from a high-density jaguar population in Belize, we identified 206 prey items (individual prey animals) in 176 independent scats representing 32 jaguars (26 males, 3 females, 3 unknown sex). The influence of pseudo-replication in the original dietary profile was minimal. The majority of scats (94%) came from male jaguars. Eight males accounted for two-thirds of the prey items, while 24 jaguars each contributed <5% of the prey items. With few exceptions, the jaguars followed the same broad diet, a 2:1:1 ratio of nine-banded armadillos (Dasypus noveminctus), other vertebrates ≤10kg, and ungulates, primarily peccaries (Tayassu pecari and Pecari tajacu). We noted prey switching between wild and domestic ungulates for individuals spanning protected forests and farmland. This first scat-based study exploring individual variation in jaguar diet highlights the importance of armadillos and peccaries for male jaguars in Belize, the need for research on their roles in supporting high-density jaguar populations, and the need for more data on female diet from across the jaguar range.

'Why would we not want to keep everybody safe?' The views of family members of people who use drugs on the implementation of drug consumption rooms in Scotland.

BACKGROUND: People who use drugs in Scotland are currently experiencing disproportionately high rates of drug-related deaths. Drug consumption rooms (DCRs) are harm reduction services that offer a safe, hygienic environment where pre-obtained drugs can be consumed under supervision. The aim of this research was to explore family member perspectives on DCR implementation in Scotland in order to inform national policy. METHODS: Scotland-based family members of people who were currently or formerly using drugs were invited to take part in semi-structured interviews to share views on DCRs. An inclusive approach to 'family' was taken, and family members were recruited via local and national networks. A convenience sample of 13 family members were recruited and interviews conducted, audio-recorded, transcribed, and analysed thematically using the Structured Framework Technique. RESULTS: Family members demonstrated varying levels of understanding regarding the existence, role, and function of DCRs. While some expressed concern that DCRs would not prevent continued drug use, all participants were in favour of DCR implementation due to a belief that DCRs could reduce harm, including saving lives, and facilitate future recovery from drug use. Participants highlighted challenges faced by people who use drugs in accessing treatment/services that could meet their needs. They identified that accessible and welcoming DCRs led by trusting and non-judgemental staff could help to meet unmet needs, including signposting to other services. Family members viewed DCRs as safe environments and highlighted how the existence of DCRs could reduce the constant worry that they had of risk of harm to their loved ones. Finally, family members emphasised the challenge of stigma associated with drug use. They believed that introduction of DCRs would help to reduce stigma and provide a signal that people who use drugs deserve safety and care. CONCLUSIONS: Reporting the experience and views of family members makes a novel and valuable contribution to ongoing public debates surrounding DCRs. Their views can be used to inform the implementation of DCRs in Scotland but also relate well to the development of wider responses to drug-related harm and reduction of stigma experienced by people who use drugs in Scotland and beyond.

Quality of life and health status in older adults (≥65 years) up to five years following colorectal cancer treatment: Findings from the ColoREctal Wellbeing (CREW) cohort study.

OBJECTIVE: Colorectal cancer (CRC) is common in older adults, with more than 70% of diagnoses in people aged ≥65 years. Despite this, there is a knowledge gap regarding longer-term outcomes in this population. Here, we identify those older people most at risk of poor quality of life (QoL) and health status in the five years following CRC treatment. MATERIALS AND METHODS: CREW is a UK longitudinal cohort study investigating factors associated with health and wellbeing recovery following curative-intent CRC surgery. Participants completed self-report questionnaires pre-surgery, then at least annually up to five years. Longitudinal analyses explored the prevalence and pre-surgery risk factors of poor QoL (QLACS-GSS) and health status (EQ-5D: presence/absence of problems in five domains) in older (≥65 years) participants over five years. RESULTS: 501 participants aged ≥65years completed questionnaires pre-surgery; 45% completed questionnaires five years later. Oldest-old participants (≥80 years) reported poorer QoL (18% higher QLACS-GSS) and 2-4 times higher odds of having problems with mobility or usual activities, compared with the youngest-old (65-69 years) over follow-up. Baseline higher self-efficacy was significantly associated with better QoL (10-30% lower QLACS-GSS scores compared to those with low self-efficacy) and lower odds of problems in all EQ-5D domains. Adequate social support was significantly associated with better QoL (8% lower QLACS-GSS) and lower odds of problems with usual activities (OR = 0.62) and anxiety/depression (OR = 0.56). CONCLUSION: There are important differences in QoL and health status outcomes for the oldest-old during CRC recovery. CREW reveals pre-surgery risk factors that are amenable to intervention including self-efficacy and social support.

The microvascular endothelial glycocalyx: An additional piece of the puzzle in veterinary medicine.

The endothelial glycocalyx (eGlx) is a critically important structure lining the luminal surface of endothelial cells. There is increasing evidence, in human patients and animal models, for its crucial role in the maintenance of health. Moreover, its damage is associated with the pathogenesis of multiple disease states. This review provides readers with an overview of the eGlx; summarising its structure, essential functions, and evidence for its role in disease. We highlight the lack of studies regarding the eGlx in cats and dogs, particularly in naturally occurring diseases. Importantly, we discuss techniques to aid its study, which can be applied to veterinary species. Finally, we present targeted therapies aimed at preserving, and in some cases, restoring damaged eGlx.

Drug Consumption Rooms and Public Health Policy: Perspectives of Scottish Strategic Decision-Makers.

There is widespread support for the introduction of Drug Consumption Rooms (DCRs) in Scotland as part of a policy response to record levels of drug-related harm. However, existing legal barriers are made more complex by the division of relevant powers between the UK and Scottish Governments. This paper reports on a national, qualitative study of key decision-makers in both local and national roles across Scotland. It explores views on the political barriers and enablers to the adoption of Drug Consumption Rooms and the potential role of these facilities in the wider treatment system. It also considers approaches to evidence, especially the types of evidence that are considered valuable in supporting decision-making in this area. The study found that Scottish decision-makers are strongly supportive of DCR adoption; however, they remain unclear as to the legal and political mechanisms that would make this possible. They view DCRs as part of a complex treatment and support system rather than a uniquely transformative intervention. They see the case for introduction as sufficient, on the basis of need and available evidence, thus adopting a pragmatic and iterative approach to evidence, in contrast to an appeal to traditional evidence hierarchies more commonly adopted by the UK Government.

Circulating hyaluronan as a marker of endothelial glycocalyx damage in dogs with myxomatous mitral valve disease and dogs in a hypercoagulable state.

The endothelial glycocalyx (eGlx) lines the luminal surface of endothelial cells, maintaining vascular health. Glycocalyx damage is pathophysiologically important in many diseases across species however few studies have investigated its breakdown in naturally occurring disease in dogs. The aims of the study were to investigate eGlx damage in dogs with myxomatous mitral valve disease (MMVD) diagnosed on echocardiography, and dogs in a hypercoagulable state diagnosed using thromboelastography (TEG), by measuring serum hyaluronan concentrations. Serum hyaluronan was quantified in dogs with MMVD (n = 27), hypercoagulability (n = 21), and in healthy controls dogs (n = 18). Serum hyaluronan concentrations were measured using a commercially-available ELISA validated for use in dogs. Hyaluronan concentrations were compared among groups using Kruskal-Wallis tests, and post-hoc with Dunn's tests. Serum hyaluronan concentrations (median [range]) were significantly increased in dogs with MMVD (62.4 [22.8-201] ng/mL; P = 0.031) and hypercoagulability (92.40 [16.9-247.6] ng/mL; P < 0.001) compared to controls (45.7 [8.7-80.2] ng/mL). Measurement of serum hyaluronan concentration offers a clinically applicable marker of eGlx health and suggests the presence of eGlx damage in dogs with MMVD and dogs in a hypercoagulable state.

Visualising the endothelial glycocalyx in dogs.

The endothelial glycocalyx (eGlx) lines the luminal surface of endothelial cells. It is critical in maintaining vascular health and when damaged contributes to many diseases. Its fragility makes studying the eGlx technically challenging. The current reference standard for eGlx visualisation, by electron microscopy using glutaraldehyde/Alcian blue perfusion fixation, has not been previously reported in dogs. Established techniques were applied to achieve visualisation of the eGlx in the microvasculature of reproductive tissue in five healthy dogs undergoing elective neutering. Uterine and testicular artery samples underwent perfusion fixation, in the presence of Alcian blue, prior to transmission electron microscopy imaging. Image processing software was used to determine eGlx depth. EGlx was visualised in the arteries of two dogs, one testicular and one uterine, with median (range) eGlx depths of 68.2 nm (32.1-122.9 nm) and 47.6 nm (26.1-129.4 nm) respectively. Study of the eGlx is technically challenging, particularly its direct visualisation in clinical samples. Further research is needed to develop more clinically applicable techniques to measure eGlx health.