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Purpose of program: Operative wait times for non-oncology-related procedures continue to rise in Canada, and this was further exacerbated by the COVID-19 pandemic. These challenges will remain prevalent beyond the pandemic given the limited number of acute care beds and resources required to care for patients. As a result, the need for innovative approaches to optimize the utilization of health care resources while maintaining equitable and timely access is needed. In this report, we describe the development of a collaborative ambulatory parathyroidectomy program between two centers in Toronto, allowing for more expedient surgical treatment of secondary hyperparathyroidism among patients from a large dialysis program. Sources of information: The need for expanded access to surgical care for secondary hyperparathyroidism was identified through interdepartmental communication between referring nephrologists and surgeons at Sunnybrook Health Sciences Centre and Women’s College Hospital, respectively. Methods: A multidisciplinary ambulatory parathyroidectomy planning team was formed that included nephrologists, endocrine surgeons, nurses, and patient care managers to conduct a needs assessment. It was identified that patients had long wait times, and to address that gap in care, a protocol was developed to identify suitable patients requiring treatment. The teams created a plan to coordinate patient care and transfers. A clinical tool and protocol for post-operative management of hypocalcemia was developed using a Delphi model, gathering input from many members of the care team. The Delphi process to finalize the protocol included a series of virtual meetings over a period of about 4 months with various stakeholders and included input from two departmental heads (medicine and surgery), three nephrologists, a nurse practitioner, a patient care manager, and two nurse educators. Meetings involved core members of the Nephrology Quality Improvement and Patient Safety at Sunnybrook Health Sciences Centre and finalized protocol was agreed upon by members of this group at a quarterly meeting. Key findings: In this article, we describe the development, initial deployment, and planned assessment of the ambulatory parathyroidectomy program at the Women’s College Hospital and Sunnybrook Health Sciences Centre. The primary aim of the program is to increase accessibility to parathyroidectomy for secondary hyperparathyroidism. A secondary aim was to allow patients to have streamlined care with a team that is well versed with maintenance dialysis needs and optimizing treatment of post operative hypocalcemia through standardized protocols. Limitations: Ambulatory parathyroidectomy relies on effective communication, flow, and availability of acute care beds. It is anticipated that occasionally, unexpected hospital demands, and health care disruptions may occur, which can limit efficiency of the program. We will also need to examine the cost-effectiveness of this program as it may improve access but increase costs related to the procedure. As the program is implemented, useful adaptations and policies to our protocol to help mitigate these limitations will be documented and published in our outcomes report. Implications: Ontario residents with chronic kidney disease with secondary hyperparathyroidism who have failed medical management will have increased and timely access to parathyroidectomy.

Introduction Heart failure (HF) symptoms improve through self-care, for which adherence remains low among patients despite the provision of education for these behaviours by clinical teams. Open Access Digital Community Promoting Self-Care, Peer Support and Health Literacy (ODYSSEE–vCHAT) combines automated digital counselling with social network support to improve mortality and morbidity, engagement with self–care materials, and health-related quality of life.Methods and analysis Use of ODYSSEE-vCHAT via Internet-connected personal computer by 162 HF patients will be compared with a control condition over 22 months. The primary outcome is a composite index score of all-cause mortality, all-cause emergency department visits, and HF-related hospitalisation at trial completion. Secondary outcomes include individual components of the composite index, engagement with self-care materials, and patient-reported measures of physical and psychosocial well-being, disease management, health literacy, and substance use. Patients are recruited from tertiary care hospitals in Toronto, Canada and randomised on a 1:1 ratio to both arms of the trial. Online assessments occur at baseline (t=0), months 4, 8 and 12, and trial completion. Ordinal logistic regression analyses and generalised linear models will evaluate primary and secondary outcomes.Ethics and dissemination The trial has been approved by the research ethics boards at the University Health Network (20-5960), Sunnybrook Hospital (5117), and Mount Sinai Hospital (21-022-E). Informed consent of eligible patients occurs in person or online. Findings will be shared with key stakeholders and the public. Results will allow for the preparation of a Canada-wide phase III trial to evaluate the efficacy of ODYSSEE-vCHAT in improving clinical outcomes and raising the standard of outpatient care.Trial registration number NCT04966104

Background: Prenatal alcohol exposure (PAE) can result in lifelong disabilities known as foetal alcohol spectrum disorder (FASD) and is associated with childhood growth deficiencies and increased bone fracture risk. However, the effects of PAE on the adult skeleton remain unclear and any potential sexual dimorphism is undetermined. Therefore, we utilised a murine model to examine sex differences with PAE on in vitro bone formation, and in the juvenile and adult skeleton., Methods: Pregnant C57BL/6J female mice received 5% ethanol in their drinking water during gestation. Primary calvarial osteoblasts were isolated from neonatal offspring and mineralised bone nodule formation and gene expression assessed. Skeletal phenotyping of 4- and 12-week-old male and female offspring was conducted by micro-computed tomography (µCT), 3-point bending, growth plate analyses, and histology., Results: Osteoblasts from male and female PAE mice displayed reduced bone formation, compared to control (≤ 30%). Vegfa, Vegfb, Bmp6, Tgfbr1, Flt1 and Ahsg were downregulated in PAE male osteoblasts only, whilst Ahsg was upregulated in PAE females. In 12-week-old mice, µCT analysis revealed a sex and exposure interaction across several trabecular bone parameters. PAE was detrimental to the trabecular compartment in male mice compared to control, yet PAE females were unaffected. Both male and female mice had significant reductions in cortical parameters with PAE. Whilst male mice were negatively affected along the tibial length, females were only distally affected. Posterior cortical porosity was increased in PAE females only. Mechanical testing revealed PAE males had significantly reduced bone stiffness compared to controls; maximum load and yield were reduced in both sexes. PAE had no effect on total body weight or tibial bone length in either sex. However, total growth plate width in male PAE mice compared to control was reduced, whilst female PAE mice were unaffected. 4-week-old mice did not display the altered skeletal phenotype with PAE observed in 12-week-old animals., Conclusions: Evidence herein suggests, for the first time, that PAE exerts divergent sex effects on the skeleton, possibly influenced by underlying sex-specific transcriptional mechanisms of osteoblasts. Establishing these sex differences will support future policies and clinical management of FASD., (© 2024. The Author(s).)

Introduction: Chondrocytes are continuously exposed to loads placed upon them. Physiological loads are pivotal to the maintenance of articular cartilage health, while abnormal loads contribute to pathological joint degradation. Similarly, the growth plate cartilage is subject to various loads during growth and development. Due to the high-water content of cartilage, hydrostatic pressure is considered one of the main biomechanical influencers on chondrocytes and has been shown to play an important role in the mechano-regulation of cartilage., Methods: Herein, we conducted RNAseq analysis of ex vivo hip cap (articular), and metatarsal (growth plate) cartilage cultures subjected to physiological (5 MPa) and injurious (50 MPa) hydrostatic pressure, using the Illumina platform (n = 4 replicates)., Results: Several hundreds of genes were shown to be differentially modulated by hydrostatic pressure, with the majority of these changes evidenced in hip cap cartilage cultures (375 significantly upregulated and 322 downregulated in 5 MPa versus control; 1022 upregulated and 724 downregulated in 50 MPa versus control). Conversely, fewer genes were differentially affected by hydrostatic pressure in the metatarsal cultures (5 significantly upregulated and 23 downregulated in 5 MPa versus control; 7 significantly upregulated and 19 downregulated in 50 MPa versus control). Using Gene Ontology annotations for Biological Processes, in the hip cap data we identified a number of pathways that were modulated by both physiological and injurious hydrostatic pressure. Pathways upregulated in response to 50 MPa versus control, included those involved in the generation of precursor metabolites and cellular respiration. Biological processes that were downregulated in this tissue included ossification, connective tissue development, and chondrocyte differentiation., Discussion: Collectively our data highlights the divergent chondrocyte phenotypes in articular and growth plate cartilage. Further, we show that the magnitude of hydrostatic pressure application has distinct effects on gene expression and biological processes in hip cap cartilage explants. Finally, we identified differential expression of a number of genes that have previously been identified as osteoarthritis risk genes, including Ctsk, and Chadl. Together these data may provide potential genetic targets for future investigations in osteoarthritis research and novel therapeutics., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2023 Bourne, Hesketh, Sharma, Bucca, Bush and Staines.)

Extracellular pyrophosphate (PP i ) is well known for its fundamental role as a physiochemical mineralisation inhibitor. However, information about its direct actions on bone cells remains limited. This study shows that PP i decreased osteoclast formation and resorptive activity by ≤50 %. These inhibitory actions were associated with reduced expression of genes involved in osteoclastogenesis (Tnfrsf11a, Dcstamp) and bone resorption (Ctsk, Car2, Acp5). In osteoblasts, PP i present for the entire (0-21 days) or latter stages of culture (7-21/14-21 days) decreased bone mineralisation by ≤95 %. However, PP i present for the differentiation phase only (0-7/0-14 days) increased bone formation (≤70 %). Prolonged treatment with PP i resulted in earlier matrix deposition and increased soluble collagen levels (≤2.3-fold). Expression of osteoblast (RUNX2, Bglap) and early osteocyte (E11, Dmp1) genes along with mineralisation inhibitors (Spp1, Mgp) was increased by PP i (≤3-fold). PP i levels are regulated by tissue non-specific alkaline phosphatase (TNAP) and ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1). PP i reduced NPP1 expression in both cell types whereas TNAP expression (≤2.5-fold) and activity (≤35 %) were increased in osteoblasts. Breakdown of extracellular ATP by NPP1 represents a key source of PP i . ATP release from osteoclasts and osteoblasts was decreased ≤60 % by PP i and by a selective TNAP inhibitor (CAS496014-12-2). Pertussis toxin, which prevents Gα i subunit activation, was used to investigate whether G-protein coupled receptor (GPCR) signalling mediates the effects of PP i . The actions of PP i on bone mineralisation, collagen production, ATP release, gene/protein expression and osteoclast formation were abolished or attenuated by pertussis toxin. Together these findings show that PP i , modulates differentiation, function and gene expression in osteoblasts and osteoclasts. The ability of PP i to alter ATP release and NPP1/TNAP expression and activity indicates that cells can detect PP i levels and respond accordingly. Our data also raise the possibility that some actions of PP i on bone cells could be mediated by a Gα i -linked GPCR., Competing Interests: Declaration of competing interest The authors have no conflict of interest., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Bone cells are known to express multiple P2 receptor subtypes, and the functional effects of receptor activation have been described for many of these. One exception is the P2X4 receptor, which despite strong expression in osteoblasts and osteoclasts, has no defined functional activity. This study used the selective P2X4 receptor antagonists, 5-BDBD and PSB-12062, to investigate the role of this receptor in bone. Both antagonists (≥ 0.1 μM) dose-dependently decreased bone formation by 60-100%. This was accompanied by a ≤ 70% decrease in alkaline phosphatase activity, a ≤ 40% reduction in cell number, and a ≤ 80% increase in the number of adipocytes present in the culture. The analysis of gene expression showed that levels of osteoblast marker genes (e.g. Alpl, Bglap) were decreased in 5-BDBD treated cells. Conversely, expression of the adipogenic transcription factor PPARG was increased 10-fold. In osteoclasts, high doses of both antagonists were associated with a reduction in osteoclast formation and resorptive activity by ≤ 95% and ≤ 90%, respectively. Taken together, these data suggest that the P2X4 receptor plays a role in modulating bone cell function. In particular, it appears to influence osteoblast differentiation favouring the osteogenic lineage over the adipogenic lineage., (© 2022. The Author(s).)

Arterial medial calcification (AMC) is the deposition of calcium phosphate in the arteries. AMC is widely thought to share similarities with physiological bone formation; however, emerging evidence suggests several key differences between these processes. N-acetylcysteine (NAC) displays antioxidant properties and can generate hydrogen sulphide (H 2 S) and glutathione (GSH) from its deacetylation to l-cysteine. This study found that NAC exerts divergent effects in vitro, increasing osteoblast differentiation and bone formation by up to 5.5-fold but reducing vascular smooth muscle cell (VSMC) calcification and cell death by up to 80%. In vivo, NAC reduced AMC in a site-specific manner by 25% but had no effect on the bone. The actions of l-cysteine and H 2 S mimicked those of NAC; however, the effects of H 2 S were much less efficacious than NAC and l-cysteine. Pharmacological inhibition of H 2 S-generating enzymes did not alter the actions of NAC or l-cysteine; endogenous production of H 2 S was also unaffected. In contrast, NAC and l-cysteine increased GSH levels in calcifying VSMCs and osteoblasts by up to 3-fold. This suggests that the beneficial actions of NAC are likely to be mediated via the breakdown of l-cysteine and the subsequent GSH generation. Together, these data show that while the molecular mechanisms driving the actions of NAC appear similar, the downstream effects on cell function differ significantly between osteoblasts and calcifying VSMCs. The ability of NAC to exert these differential actions further supports the notion that there are differences between the development of pathological AMC and physiological bone formation. NAC could represent a therapeutic option for treating AMC without exerting negative effects on bone., (© 2021 The Authors. Journal of Cellular Physiology published by Wiley Periodicals LLC.)