The effect of focused lung ultrasonography on antibiotic prescribing in patients with acute lower respiratory tract infections in Danish general practice: study protocol for a pragmatic randomized controlled trial (PLUS-FLUS).

BACKGROUND: The use of antibiotics is a key driver of antimicrobial resistance and is considered a major threat to global health. In Denmark, approximately 75% of antibiotic prescriptions are issued in general practice, with acute lower respiratory tract infections (LRTIs) being one of the most common indications. Adults who present to general practice with symptoms of acute LRTI often suffer from self-limiting viral infections. However, some patients have bacterial community-acquired pneumonia (CAP), a potential life-threatening infection, that requires immediate antibiotic treatment. Importantly, no single symptom or specific point-of-care test can be used to discriminate the various diagnoses, and diagnostic uncertainty often leads to (over)use of antibiotics. At present, general practitioners (GPs) lack tools to better identify those patients who will benefit from antibiotic treatment. The primary aim of the PLUS-FLUS trial is to determine whether adults who present with symptoms of an acute LRTI in general practice and who have FLUS performed in addition to usual care are treated less frequently with antibiotics than those who only receive usual care. METHODS: Adults (≥ 18 years) presenting to general practice with acute cough (< 21 days) and at least one other symptom of acute LRTI, where the GP suspects a bacterial CAP, will be invited to participate in this pragmatic randomized controlled trial. All participants will receive usual care. Subsequently, participants will be randomized to either the control group (usual care) or to an additional focused lung ultrasonography performed by the GP (+ FLUS). The primary outcome is the proportion of participants with antibiotics prescribed at the index consultation (day 0). Secondary outcomes include comparisons of the clinical course for participants in groups. DISCUSSION: We will examine whether adults who present with symptoms of acute LRTI in general practice, who have FLUS performed in addition to usual care, have antibiotics prescribed less frequently than those given usual care alone. It is highly important that a possible reduction in antibiotic prescriptions does not compromise patients' recovery or clinical course, which we will assess closely. TRIAL REGISTRATION: ClinicalTrials.gov NCT06210282. Registered on January 17, 2024.

Impact of breast-, gastrointestinal-, and lung cancer on prognosis in patients with first-time pulmonary embolism: A Danish nationwide cohort study.

BACKGROUND: Pulmonary embolism (PE) is described as a prognostic factor in patients with cancer however, the prognostic impact of PE remains unknown. This study investigated, the 1-year prognosis following PE in patients with breast-, gastrointestinal-, or lung cancer stratified by cancer status. METHODS: All Danish patients with first-time PE from 2008 to 2018 were included. Cancer status was categorized as no cancer, history of cancer, non-active cancer and active cancer. Unadjusted and age-stratified 1-year risk of death was estimated using the Kaplan-Meier estimator. Cause of death was reported using the Aalen-Johansen method. RESULTS: Of 35,679 patients with PE, 18% had a breast-, gastrointestinal-, or lung cancer. Patients with cancer were older compared with no cancer (69.8 years [IQR: 56.2-79.8]). One-year risk of death (95% confidence interval) for active breast-, gastrointestinal-, and lung cancer was 49.5% (44.0%-54.9%), 75.0% (72.5%-77.4%) and 80.1% (78.0%-82.3%) respectively, compared with 18.9% (18.4%-19.3%) for no cancer. Age-stratified analysis revealed no association with increasing age in non-active lung cancer and all active cancers. Further, non-cardiovascular death accounted for an increasing proportion by cancer status (no cancer < history of cancer < non-active cancer < active cancer). CONCLUSIONS: One-year risk of death was dependent on both cancer type and status; no association with age was found for patients with active cancers. Non-cardiovascular death was leading in non-active and active cancers. Thus, the occurrence of first-time PE could be regarded as a marker of cancer severity for patients with breast-, gastrointestinal-, and lung cancer.

Intraarticular treatment with integrin α10ß1-selected mesenchymal stem cells affects microRNA expression in experimental post-traumatic osteoarthritis in horses.

Osteoarthritis (OA) remains a major cause of lameness in horses, which leads to lost days of training and early retirement. Still, the underlying pathological processes are poorly understood. MicroRNAs (miRNAs) are small non-coding RNAs that serve as regulators of many biological processes including OA. Analysis of miRNA expression in diseased joint tissues such as cartilage and synovial membrane may help to elucidate OA pathology. Since integrin α10ß1-selected mesenchymal stem cell (integrin α10-MSC) have shown mitigating effect on equine OA we here investigated the effect of integrin α10-MSCs on miRNA expression. Cartilage and synovial membrane was harvested from the middle carpal joint of horses with experimentally induced, untreated OA, horses with experimentally induced OA treated with allogeneic adipose-derived MSCs selected for the marker integrin α10-MSCs, and from healthy control joints. miRNA expression in cartilage and synovial membrane was established by quantifying 70 pre-determined miRNAs by qPCR. Differential expression of the miRNAs was evaluated by comparing untreated OA and control, untreated OA and MSC-treated OA, and joints with high and low pathology score. A total of 60 miRNAs were successfully quantified in the cartilage samples and 55 miRNAs were quantified in the synovial membrane samples. In cartilage, miR-146a, miR-150 and miR-409 had significantly higher expression in untreated OA joints than in control joints. Expression of miR-125a-3p, miR-150, miR-200c, and miR-499-5p was significantly reduced in cartilage from MSC-treated OA joints compared to the untreated OA joints. Expression of miR-139-5p, miR-150, miR-182-5p, miR-200a, miR-378, miR-409-3p, and miR-7177b in articular cartilage reflected pathology score. Several of these miRNAs are known from research in human patients with OA and from murine OA models. Our study shows that these miRNAs are also differentially expressed in experimental equine OA, and that expression depends on OA severity. Moreover, MSC treatment, which resulted in less severe OA, also affected miRNA expression in cartilage.

Empagliflozin to elderly and obese patients with increased risk of developing heart failure: Study protocol for the Empire Prevent trial program.

INTRODUCTION: Sodium-glucose cotransporter 2 (SGLT2) inhibitors have previously demonstrated cardioprotective properties in patients with type 2 diabetes, suggesting a preventive effect on heart failure (HF). The Empire Prevent trial program investigates the therapeutic potential for HF prevention by evaluating the cardiac, metabolic, and renal effects of the SGLT2 inhibitor empagliflozin in patients with increased risk of developing HF, but without diabetes or established HF. METHODS: The Empire Prevent trial program is an investigator-initiated, double-blind, randomized clinical trial program including elderly and obese patients (60-84 years, body mass index >28 kg/m2) with at least one manifestation of hypertension, cardiovascular or chronic kidney disease, but no history of diabetes or HF. The aims are to investigate the effects of empagliflozin on 1) physical capacity and left ventricular and atrial structural changes with peak oxygen consumption and left ventricular mass as primary endpoints (Empire Prevent Cardiac), and 2) cardiac-adipose tissue interaction and volume homeostasis with primary endpoints of changes in epicardial adipose tissue and estimated extracellular volume (Empire Prevent Metabolic). At present, 138 of 204 patients have been randomized in the Empire Prevent trial program. Patients are randomized 1:1 to 180 days treatment with empagliflozin 10 mg daily or placebo, while undergoing a comprehensive examination program at baseline and follow-up. DISCUSSION: The Empire Prevent trial program will mark the first step towards elucidating the potential of SGLT2 inhibition for HF prevention in an outpatient setting in elderly and obese patients with increased risk of developing HF, but with no history of diabetes or established HF. Furthermore, the Empire Prevent trial program will supplement the larger event-driven trials by providing mechanistic insights to the beneficial effects of SGLT2 inhibition. TRIAL REGISTRATION: Both parts of the trial program have been registered on September 13th 2021 (Clinical Trial Registration numbers: NCT05084235 and NCT05042973) before enrollment of the first patient. All patients will provide oral and written informed consent. The trial is approved by The Regional Committee on Health Research Ethics and the Danish Medicines Agency. Data will be disseminated through scientific meetings and peer-reviewed journals irrespective of outcome.

Integrin α10ß1-Selected Mesenchymal Stem Cells Reduce Pain and Cartilage Degradation and Increase Immunomodulation in an Equine Osteoarthritis Model.

OBJECTIVE: Integrin α10ß1-selected mesenchymal stem cells (integrin α10-MSCs) have previously shown potential in treating cartilage damage and osteoarthritis (OA) in vitro and in animal models in vivo. The aim of this study was to further investigate disease-modifying effects of integrin α10-MSCs. DESIGN: OA was surgically induced in 17 horses. Eighteen days after surgery, horses received 2 × 107 integrin α10-MSCs intra-articularly or were left untreated. Lameness and response to carpal flexion was assessed weekly along with synovial fluid (SF) analysis. On day 52 after treatment, horses were euthanized, and carpi were evaluated by computed tomography (CT), MRI, histology, and for macroscopic pathology and integrin α10-MSCs were traced in the joint tissues. RESULTS: Lameness and response to carpal flexion significantly improved over time following integrin α10-MSC treatment. Treated horses had milder macroscopic cartilage pathology and lower cartilage histology scores than the untreated group. Prostaglandin E2 and interleukin-10 increased in the SF after integrin α10-MSC injection. Integrin α10-MSCs were found in SF from treated horses up to day 17 after treatment, and in the articular cartilage and subchondral bone from 5 of 8 treated horses after euthanasia at 52 days after treatment. The integrin α10-MSC injection did not cause joint flare. CONCLUSION: This study demonstrates that intra-articular (IA) injection of integrin α10-MSCs appears to be safe, alleviate pathological changes in the joint, and improve joint function in an equine post-traumatic osteoarthritis (PTOA) model. The results suggest that integrin α10-MSCs hold promise as a disease-modifying osteoarthritis drug (DMOAD).

Factors affecting point-of-care ultrasound implementation in general practice: a survey in Danish primary care clinics.

OBJECTIVE: The implementation of point-of-care ultrasound (POCUS) in general practice varies, but it is unknown what determines this variation. The purpose of this study was to explore (1) the overall proportion of POCUS-users among general practitioners (GPs), (2) the current use of POCUS by GPs, (3) factors related to the implementation of POCUS in general practice and (4) GPs' concerns related to POCUS use in general practice. DESIGN: An online survey was distributed in June 2019. SETTING: General practice. PARTICIPANTS: GPs working in office-based primary care clinics in Denmark. MAIN OUTCOME MEASURES: The questionnaire was developed using mixed methods and included questions about participants' characteristics, past POCUS training and experience, capability, opportunity and motivation for using POCUS in the primary care setting. Results were summarised using descriptive statistics. Association between GPs' background characteristics and POCUS use was tested using logistics regression. RESULTS: Responses were analysed from 1216 questionnaires corresponding to 36.4% of all GPs in Denmark. The majority (72.3%) of participants had previous POCUS experience, 14.7% had access to a POCUS device and 11.5% used POCUS. Several factors motivated participants to use POCUS. However, barriers existed such as lack of remuneration and high workload. Additionally, many GPs questioned their ability to scan with sufficient diagnostic accuracy and the impact of POCUS on the consultation. Of non-users, 28.7% believed they would be using POCUS in the future. CONCLUSION: Although, the majority of GPs had past experience with POCUS and felt motivated to use it, few had implemented POCUS. Several factors influenced the GPs' capability, opportunity and motivation for using POCUS and several concerns were registered by non-users.

Quantitative image mean squared displacement (iMSD) analysis of the dynamics of Aquaporin 2 within the membrane of live cells.

Nanodomains are a biological membrane phenomenon which have a large impact on various cellular processes. They are often analysed by looking at the lateral dynamics of membrane lipids or proteins. The localization of the plasma membrane protein aquaporin-2 in nanodomains has so far been unknown. In this study, we use total internal reflection fluorescence microscopy to image Madin-Darby Canine Kidney (MDCK) cells expressing aquaporin-2 tagged with mEos 3.2. Then, image mean squared displacement (iMSD) approach was used to analyse the diffusion of aquaporin-2, revealing that aquaporin-2 is confined within membrane nanodomains. Using iMSD analysis, we found that the addition of the drug forskolin increases the diffusion of aquaporin-2 within the confined domains, which is in line with previous studies. Finally, we observed an increase in the size of the membrane domains and the extent of trapping of aquaporin-2 after stimulation with forskolin.

Patient mortality following new-onset heart failure stratified by cancer type and status.

AIM: Expected 1-year survival is essential to risk stratification of patients with heart failure (HF); however, little is known about the 1-year prognosis of patients with HF and cancer. Thus, the objective was to investigate the 1-year prognosis following new-onset HF stratified by cancer status in patients with breast, gastrointestinal, or lung cancer. METHODS AND RESULTS: All Danish patients with new-onset HF from 2000 to 2018 were included. Cancer status was categorized as history of cancer (no cancer-related contact within 5 years of HF diagnosis), non-active cancer (curative intended procedure administered) and active cancer. Standardized 1-year all-cause mortality was reported using G-computation. Age-stratified 1-year all-cause mortality was estimated using the Kaplan-Meier estimator. In total, 193 359 patients with HF were included, 7.3% had either a breast, gastrointestinal, or lung cancer diagnosis. Patients with cancer were older and more comorbid than patients without cancer. Standardized 1-year all-cause mortality (95% confidence intervals) was 24.6% (23.0-26.2%), 27.1% (25.5-28.6%), and 29.9% (25.9-34.0%) for history of breast, gastrointestinal and lung cancer, respectively, which was comparable to patients with non-active cancers. For active breast, gastrointestinal and lung cancer, standardized 1-year all-cause mortality was 36.2% (33.8-38.6%), 49.0% (47.2-50.9%), and 61.6% (59.7-63.5%), respectively. One-year all-cause mortality increased incrementally with age, except for active lung cancer. CONCLUSION: Standardized 1-year all-cause mortality was comparable for patients with history of cancer and non-active cancer regardless of cancer type, but varied comprehensively for active cancers. Prognostic impact of age was limited for active lung cancer. Thus, granular stratification of cancer is necessary for optimized management of new-onset HF.

4-Oxo-2-nonenal-Induced α-Synuclein Oligomers Interact with Membranes in the Cell, Leading to Mitochondrial Fragmentation.

Oxidative stress and formation of cytotoxic oligomers by the natively unfolded protein α-synuclein (α-syn) are both connected to the development of Parkinson's disease. This effect has been linked to lipid peroxidation and membrane disruption, but the specific mechanisms behind these phenomena remain unclear. To address this, we have prepared α-syn oligomers (αSOs) in vitro in the presence of the lipid peroxidation product 4-oxo-2-nonenal and investigated their interaction with live cells using in-cell NMR as well as stimulated emission depletion (STED) super-resolution and confocal microscopy. We find that the αSOs interact strongly with organellar components, leading to strong immobilization of the protein's otherwise flexible C-terminus. STED microscopy reveals that the oligomers localize to small circular structures inside the cell, while confocal microscopy shows mitochondrial fragmentation and association with both late endosome and retromer complex before the SOs interact with mitochondria. Our study provides direct evidence for close contact between cytotoxic α-syn aggregates and membraneous compartments in the cell.

Bacterial findings in patients referred to hospital for the treatment of acute tonsillitis with or without peritonsillar phlegmon.

BACKGROUND: The vast majority of patients with acute tonsillitis (AT) are managed in general practice. However, occasionally patients are referred to hospital for specialized management because of aggravated symptoms and/or findings suggestive of peritonsillar involvement. No prospective studies have been conducted aiming to investigate the prevalent and significant microorganisms in this highly selected group of patients. We aimed to describe the microbiological findings of acute tonsillitis with or without peritonsillar phlegmon (PP) in patients referred for hospital treatment and to point out potential pathogens using the following principles to suggest pathogenic significance: (1) higher prevalence in patients compared to healthy controls, (2) higher abundance in patients compared to controls, and (3) higher prevalence at time of infection compared to time of follow up. METHODS: Meticulous and comprehensive cultures were performed on tonsillar swabs from 64 patients with AT with (n = 25) or without (n = 39) PP and 55 healthy controls, who were prospectively enrolled at two Danish Ear-Nose-Throat Departments between June 2016 and December 2019. RESULTS: Streptococcus pyogenes was significantly more prevalent in patients (27%) compared to controls (4%) (p < 0.001). Higher abundance was found in patients compared to controls for Fusobacterium necrophorum (mean 2.4 vs. 1.4, p = 0.017) and S. pyogenes (mean 3.1 vs. 2.0, p = 0.045) in semi-quantitative cultures. S. pyogenes, Streptococcus dysgalactiae, and Prevotella species were significantly more prevalent at time of infection compared to follow up (p = 0.016, p = 0.016, and p = 0.039, respectively). A number of species were detected significantly less frequently in patients compared to controls and the mean number of species was significantly lower in patients compared to controls (6.5 vs. 8.3, p < 0.001). CONCLUSIONS: Disregarding Prevotella spp. because of the prevalence in healthy controls (100%), our findings suggest that S. pyogenes, F. necrophorum, and S. dysgalactiae are significant pathogens in severe AT with or without PP. In addition, infections were associated with reduced diversity (dysbacteriosis). TRIAL REGISTRATION: The study is registered in the ClinicalTrials.gov protocol database (# 52,683). The study was approved by the Ethical Committee at Aarhus County (# 1-10-72-71-16) and by the Danish Data Protection Agency (# 1-16-02-65-16).

May the proton motive force be with you: A plant transporter review.

As our ecosystems experience challenges associated with climate change, an improved understanding of the fundamental biochemical processes governing plant physiology is needed. Strikingly, current structural information on plant membrane transporters is severely limited compared to other kingdoms of life, with only 18 unique structures in total. To advance future breakthroughs and insight in plant cell molecular biology, structural knowledge of membrane transporters is indispensable. This review summarizes the current status of structural knowledge in the plant membrane transporter field. Plants utilize the proton motive force (PMF) to drive secondary active transport. We discuss the PMF, how it relates to secondary active transport and provide a classification of PMF driven secondary active transport, discussing recently published structures of symporters, antiporters, and uniporters from plants.

Angiotensin II Treatment Induces Reorganization and Changes in the Lateral Dynamics of Angiotensin II Type 1 Receptor in the Plasma Membrane Elucidated by Photoactivated Localization Microscopy Combined with Image Spatial Correlation Analysis.

The mechanisms by which angiotensin II type 1 receptor is distributed and the diffusional pattern in the plasma membrane (PM) remain unclear, despite their crucial role in cardiovascular homeostasis. In this work, we obtained quantitative information of angiotensin II type 1 receptor (AT1R) lateral dynamics as well as changes in the diffusion properties after stimulation with ligands in living cells using photoactivated localization microscopy (PALM) combined with image spatial-temporal correlation analysis. To study the organization of the receptor at the nanoscale, expansion microscopy (ExM) combined with PALM was performed. This study revealed that AT1R lateral diffusion increased after binding to angiotensin II (Ang II) and the receptor diffusion was transiently confined in the PM. In addition, ExM revealed that AT1R formed nanoclusters at the PM and the cluster size significantly decreased after Ang II treatment. Taking these results together suggest that Ang II binding and activation cause reorganization and changes in the dynamics of AT1R at the PM.

Effects of empagliflozin on erythropoiesis in heart failure: data from the Empire HF trial.

AIMS: It remains unknown whether the consistently observed increase in haematocrit with sodium-glucose cotransporter 2 inhibitors is caused by diuresis-associated haemoconcentration or increased erythropoiesis. We aimed to investigate the early effect of empagliflozin on erythropoiesis and iron metabolism in patients with heart failure with reduced ejection fraction (HFrEF). METHODS AND RESULTS: The Empire HF was a double-blind, randomized, placebo-controlled trial. Patients with a left ventricular ejection fraction (LVEF) ≤40%, New York Heart Association (NYHA) class I-III symptoms, and on stable guideline-directed HFrEF therapy were randomly assigned (1:1) to empagliflozin or matching placebo once daily for 12 weeks. Exploratory outcomes reflecting changes in erythropoiesis and iron metabolism were analysed. In total, 190 patients were randomized. Baseline characteristics were well-balanced between the groups (age: mean 64 [± 11] years; male: 85%; LVEF: mean 29 [± 8)%; NYHA class II: 78%; type 2 diabetes: 13%; anaemia: 28%; chronic kidney disease: 13%). In this post hoc analysis, erythropoietin was increased with empagliflozin compared to placebo from baseline to 12 weeks (adjusted mean difference 2.6 IU/L, 95% confidence interval [CI] 0.8-4.4; p = 0.0046). Moreover, hepcidin was reduced (adjusted ratio of change 0.76, 95% CI 0.59-0.97; p = 0.031), with no change observed for erythroferrone (adjusted ratio of change 1.17, 95% CI 0.86-1.60; p = 0.31) compared to placebo. No significant treatment-by-subgroup interactions were observed regarding baseline type 2 diabetes, anaemia, or chronic kidney disease (pinteraction >0.05). CONCLUSION: These findings suggest that empagliflozin increases erythropoiesis and augments early iron utilization in patients with HFrEF. These mechanisms may contribute to the cardioprotective properties of empagliflozin.

Prognosis of acute coronary syndrome stratified by cancer type and status - a nationwide cohort study.

BACKGROUND: To investigated the prognosis of the most prevalent cancers (breast-, gastrointestinal-, and lung cancer), according to cancer status (i.e., active-, non-active-, history of-, and no cancer), following first-time of acute coronary syndrome (ACS). METHODS: Danish nationwide registers were used to identify patients with first-time ACS from 2000-2018. Patients were stratified according to cancer type and status. Hazard ratios (HR) estimated by adjusted Cox regression models for 1year all-cause mortality reported. Further absolute risks of 1year cardiovascular versus non-cardiovascular death and 30-day cumulative incidence of coronary angiograms (CAG) was estimated, using the Aalen-Johansen non-parametric method, with competing risk of death. RESULTS: We identified 150,478 (95.7%) with no cancer, 2,370 (1.5%) with history of cancer, 2,712 (1.7%) with non-active cancer and 1,704 (1.1%) with active cancer. Cancer patients were older with more comorbidities than patients with no cancer. When compared with no cancer, we found HRs (95% confidence intervals) of 1.71 (1.44-2.02), 2.47 (2.23-2.73) and 4.22 (3.87-4.60) correspondingly for active breast-, gastrointestinal-, and lung cancer. Increased HRs were also found for non-active cancers, but not for history of cancer. Cardiovascular disease was the leading cause of death in all patients. Among patients with active breast-, gastrointestinal-, and lung cancer 43%, 43%, and 31% underwent CAG, correspondingly, compared with 77% of patients without cancer. CONCLUSIONS: Active- and non-active cancers were associated with an increased 1-year all-cause mortality compared with patients with history of cancer and no cancer. Cardiovascular disease was the leading cause of death; notably CAG was less frequently performed in cancer patients.

Influence of angiotensin receptor-neprilysin inhibition on the efficacy of Empagliflozin on cardiac structure and function in patients with chronic heart failure and a reduced ejection fraction: The Empire HF trial.

Study objective: The objective was to assess the effect of ongoing angiotensin receptor-neprilysin inhibitor(ARNI) on the effect of the sodium glucose cotransporter 2 (SGLT2) inhibitor empagliflozin on left ventricular (LV) size and function in patients with heart failure and reduced ejection fraction(HFrEF). Design: Post hoc analysis of the Empire HF trial, an investigator-initiated, double-blind, randomized controlled trial. Participants: 190 patients with HFrEF with New York Heart association class I-III symptoms with an ejection fraction of 40 % or below. Patients were stratified according to ongoing ARNI treatment at baseline. Intervention: Empagliflozin 10 mg daily or placebo for 12 weeks. Echocardiography at baseline and follow-up. Main outcome measures: Left ventricular end-systolic volume index (LVESVI), end-diastolic volume index (LVEDVI), left atrial volume index (LAVI), left ventricular ejection fraction (LVEF). Results: A total of 58 patients (31 %) received ARNI at baseline. Compared to with placebo, empagliflozin reduced the LVESVI ([-6.2 (-14.1 to 1.6); p = 0.12] and [-3.3 (-8.2 to 1.6); p = 0.19], interaction P = 0.49), LVEDVI ([-11.2 (-21.2 to -1.2); p = 0.03] and [-2.9 (-8.7 to 2.9); p = 0.32], interaction P = 0.13), and LAVI ([-3.9 (-9.1 to 1.2); p = 0.14] and. [-1.8 (-4.4 to 0.7); p = 0.16], respectively, interaction P = 0.9) in patients treated with and without ARNI at baseline, respectively. No treatment-by-ARNI subgroup interaction were found. Unaffected by baseline ARNI treatment, empagliflozin did not improve LVEF. Conclusion: The effect of empagliflozin on cardiac structure and function compared to placebo was not affected by background treatment with ARNI.

Temporal extracellular vesicle protein changes following intraarticular treatment with integrin α10ß1-selected mesenchymal stem cells in equine osteoarthritis.

Introduction: Equine osteoarthritis (OA) is a heterogeneous, degenerative disease of the musculoskeletal system with multifactorial causation, characterized by a joint metabolic imbalance. Extracellular vesicles are nanoparticles involved in intracellular communication. Mesenchymal stem cell (MSC) therapy is a form of regenerative medicine that utilizes their properties to repair damaged tissues. Despite its wide use in veterinary practice, the exact mechanism of action of MSCs is not fully understood. The aim of this study was to determine the synovial fluid extracellular vesicle protein cargo following integrin α10ß1-selected mesenchymal stem cell (integrin α10-MSC) treatment in an experimental model of equine osteoarthritis with longitudinal sampling. Methods: Adipose tissue derived, integrin α10-MSCs were injected intraarticularly in six horses 18 days after experimental induction of OA. Synovial fluid samples were collected at day 0, 18, 21, 28, 35, and 70. Synovial fluid was processed and extracellular vesicles were isolated and characterized. Extracellular vesicle cargo was then analyzed using data independent acquisition mass spectrometry proteomics. Results: A total of 442 proteins were identified across all samples, with 48 proteins differentially expressed (FDR ≤ 0.05) between sham-operated control joint without MSC treatment and OA joint treated with MSCs. The most significant pathways following functional enrichment analysis of the differentially abundant protein dataset were serine endopeptidase activity (p = 0.023), complement activation (classical pathway) (p = 0.023), and collagen containing extracellular matrix (p = 0.034). Due to the lack of an OA group without MSC treatment, findings cannot be directly correlated to only MSCs. Discussion: To date this is the first study to quantify the global extracellular vesicle proteome in synovial fluid following MSC treatment of osteoarthritis. Changes in the proteome of the synovial fluid-derived EVs following MSC injection suggest EVs may play a role in mediating the effect of cell therapy through altered joint homeostasis. This is an important step toward understanding the potential therapeutic mechanisms of MSC therapy, ultimately enabling the improvement of therapeutic efficacy.

A detailed macroscopic scoring system for experimental post-traumatic Osteoarthritis in the equine middle carpal joint.

OBJECTIVE: Osteoarthritis (OA) is a significant health issue in humans as well as horses. Experimental models of equine carpal OA have been used to investigate OA pathogenesis and potential therapeutic candidates. A 5-scale scoring system (OARSI) for macroscopic pathological cartilage changes already exists, but there is a need for a scoring system with better differentiation of severity. The aim of this study was therefore to develop and validate such a scoring system. RESULTS: New scoring system were developed for cartilage erosions (Copenhagen Equine Total Cartilage Score, CEqTCS) along with synovial membrane pathology and osteochondral fragment healing (Copenhagen Equine Carpal Osteoarthritis Score, CEqCOAS). For the CEqTCS there was excellent intraclass agreement (ICC = 0.993; CI 0.985-0.996; p = 1.08e-31) and consistency (ICC = 0.992; CI 0.985-0.996; p = 4.61e-31), as well as excellent interclass agreement (ICC = 0.974; CI 0.948-0.987, p = 2e-22) and consistency (ICC = 0.973; CI 0.946-0.987; p = 2.77e-22), while the OARSI system had moderate (κ = 0.47) and weak (κ = 0.28) inter- and intra-class agreement, respectively. The OARSI score and the CEqTCS correlated excellently, but every OARSI grade encompassed a wide range of CEqTCS grades. The new score for assessment of equine OA provides means to a better differentiation of OA changes than the existing OARSI system.

Human integrin α10ß1-selected mesenchymal stem cells home to cartilage defects in the rabbit knee and assume a chondrocyte-like phenotype.

BACKGROUND: Mesenchymal stem cells (MSCs) have shown promising results in stimulating cartilage repair and in the treatment of osteoarthritis (OA). However, the fate of the MSCs after intra-articular injection and their role in cartilage regeneration is not clear. To address these questions, this study investigated (1) homing of labeled human adipose tissue derived integrin α10ß1-selected MSCs (integrin α10-MSCs) to a cartilage defect in a rabbit model and (2) the ability of the integrin α10-MSCs to differentiate to chondrocytes and to produce cartilage matrix molecules in vivo. DESIGN: Integrin α10-MSCs were labeled with superparamagnetic iron oxide nanoparticles (SPIONs) co-conjugated with Rhodamine B to allow visualization by both MRI and fluorescence microscopy. A cartilage defect was created in the articular cartilage of the intertrochlear groove of the femur of rabbits. Seven days post-surgery, labeled integrin α10-MSCs or vehicle were injected into the joint. Migration and distribution of the SPION-labeled integrin α10-MSCs was evaluated by high-field 9.4 T MRI up to 10 days after injection. Tissue sections from the repair tissue in the defects were examined by fluorescence microscopy. RESULTS: In vitro characterization of the labeled integrin α10-MSCs demonstrated maintained viability, proliferation rate and trilineage differentiation capacity compared to unlabeled MSCs. In vivo MRI analysis detected the labeled integrin α10-MSCs in the cartilage defects at all time points from 12 h after injection until day 10 with a peak concentration between day 1 and 4 after injection. The labeled MSCs were also detected lining the synovial membrane at the early time points. Fluorescence analysis confirmed the presence of the labeled integrin α10-MSCs in all layers of the cartilage repair tissue and showed co-localization between the labeled cells and the specific cartilage molecules aggrecan and collagen type II indicating in vivo differentiation of the MSCs to chondrocyte-like cells. No adverse effects of the α10-MSC treatment were detected during the study period. CONCLUSION: Our results demonstrated migration and homing of human integrin α10ß1-selected MSCs to cartilage defects in the rabbit knee after intra-articular administration as well as chondrogenic differentiation of the MSCs in the regenerated cartilage tissue.