Serial injections of 4% polyacrylamide hydrogel have no detrimental effects in equine joints following clinical, histologic, and synovial biomarker evaluation.

OBJECTIVE: Polyacrylamide hydrogel (4% PAHG) is an inert viscoelastic supplement used to manage osteoarthritis in horses. Even with a prolonged clinical effect, horses may be administered multiple doses during their performance career. The effect of the serial 4% PAHG treatments is not known. The objectives of this study were to evaluate the clinical, histologic, and synovial fluid biomarker effects following serial administration of 4% PAHG in normal equine fetlock joints. ANIMALS: 8 healthy horses. METHODS: In a blinded, controlled in vivo study, horses received serial intra-articular injections of 4% PAHG (Noltrex Vet; Nucleus ProVets LLC) and contralateral 0.9% saline control on days 0, 45, 90, and 135. Treatment and control joints were randomly assigned. Synovial fluid was collected before administration of 4% PAHG or 0.9% saline on day 0 and at study completion for cellular and biomarker evaluation. Serial physical and lameness examinations were performed throughout the study. On day 240, gross examination and harvest of cartilage and synovial membrane for histology were completed. RESULTS: There were no histologic changes in articular cartilage or synovial fluid biomarkers. The 4% PAHG was seen on the surface of the synovium in 5 of 8 treated joints 105 days after the last treatment. There are minimal effects following serial injections of 4% PAHG on normal joints in horses following administration at 0, 45, 90, and 135 days, with final evaluation on day 240. CLINICAL RELEVANCE: Serial administration of intra-articular 4% PAHG in horses may provide long-term joint lubrication with no detrimental effects.

Functional Pdgfra fibroblast heterogeneity in normal and fibrotic mouse lung.

Aberrant fibroblast function plays a key role in the pathogenesis of idiopathic pulmonary fibrosis, a devastating disease of unrelenting extracellular matrix deposition in response to lung injury. Platelet-derived growth factor α-positive (Pdgfra+) lipofibroblasts (LipoFBs) are essential for lung injury response and maintenance of a functional alveolar stem cell niche. Little is known about the effects of lung injury on LipoFB function. Here, we used single-cell RNA-Seq (scRNA-Seq) technology and PdgfraGFP lineage tracing to generate a transcriptomic profile of Pdgfra+ fibroblasts in normal and injured mouse lungs 14 days after bleomycin exposure, generating 11 unique transcriptomic clusters that segregated according to treatment. While normal and injured LipoFBs shared a common gene signature, injured LipoFBs acquired fibrogenic pathway activity with an attenuation of lipogenic pathways. In a 3D organoid model, injured Pdgfra+ fibroblast-supported organoids were morphologically distinct from those cultured with normal fibroblasts, and scRNA-Seq analysis suggested distinct transcriptomic changes in alveolar epithelia supported by injured Pdgfra+ fibroblasts. In summary, while LipoFBs in injured lung have not migrated from their niche and retain their lipogenic identity, they acquire a potentially reversible fibrogenic profile, which may alter the kinetics of epithelial regeneration and potentially contribute to dysregulated repair, leading to fibrosis.

Disruption of anthrax toxin receptor 1 in pigs leads to a rare disease phenotype and protection from senecavirus A infection.

Senecavirus A (SVA) is a cause of vesicular disease in pigs, and infection rates are rising within the swine industry. Recently, anthrax toxin receptor 1 (ANTXR1) was revealed as the receptor for SVA in human cells. Herein, the role of ANTXR1 as a receptor for SVA in pigs was investigated by CRISPR/Cas9 genome editing. Strikingly, ANTXR1 knockout (KO) pigs exhibited features consistent with the rare disease, GAPO syndrome, in humans. Fibroblasts from wild type (WT) pigs supported replication of SVA; whereas, fibroblasts from KO pigs were resistant to infection. During an SVA challenge, clinical symptoms, including vesicular lesions, and circulating viremia were present in infected WT pigs but were absent in KO pigs. Additional ANTXR1-edited piglets were generated that were homozygous for an in-frame (IF) mutation. While IF pigs presented a GAPO phenotype similar to the KO pigs, fibroblasts showed mild infection, and circulating SVA nucleic acid was decreased in IF compared to WT pigs. Thus, this new ANTXR1 mutation resulted in decreased permissiveness of SVA in pigs. Overall, genetic disruption of ANTXR1 in pigs provides a unique model for GAPO syndrome and prevents circulating SVA infection and clinical symptoms, confirming that ANTXR1 acts as a receptor for the virus.

In vitro antimicrobial activity of equine platelet lysate and mesenchymal stromal cells against common clinical pathogens.

Septic arthritis is considered a medical emergency. Disease following bacterial colonization can lead to significant morbidity and mortality and requires costly treatment. Antimicrobial properties of regenerative therapies, including mesenchymal stromal cells and platelet products, have been researched extensively in human medicine. Although fewer studies have been conducted in veterinary species, they have shown promising results. The purpose of this study was to evaluate bacterial suppression by equine platelet lysate (EPL) and adipose-derived mesenchymal stromal cells (ASCs) in vitro. We hypothesized that both products would significantly inhibit the growth of Staphylococcus aureus and Escherichia coli. Pooled blood from 10 horses was used for production of EPL. Mesenchymal stromal cells were isolated from adipose tissue harvested from the gluteal region of 3 horses. The study evaluated 3 treatment groups: 10 × EPL, 1.6 million ASCs, and a control, using an incomplete unbalanced block design with repeated measurements. Optical density readings and colony-forming units/mL were calculated at 0, 3, 6, 9, 12, 18, and 24 hours. Decreased bacterial growth was seen at multiple time points for the S. aureus-ASC and S. aureus-EPL treatments, supporting our hypothesis. Increased bacterial growth was noticed in the E. coli-EPL group, with no difference in the E. coli-ASC treatment, which opposed our hypothesis. A clear conclusion of antimicrobial effects of EPL and ASCs cannot be made from this in vitro study. Although it appears that ASCs have a significant effect on decreasing the growth of S. aureus, further studies are needed to explore these effects, particularly in Gram-positive bacteria.

L'arthrite septique est considérée comme une urgence médicale. La maladie consécutive à une colonisation bactérienne peut entraîner une morbidité et une mortalité importantes et nécessite un traitement coûteux. Les propriétés antimicrobiennes des thérapies régénératives, y compris les cellules stromales mésenchymateuses et les produits plaquettaires, ont fait l'objet de recherches approfondies en médecine humaine. Bien que moins d'études aient été menées chez les espèces animales, elles ont montré des résultats prometteurs. Le but de cette étude était d'évaluer la suppression bactérienne par le lysat plaquettaire équin (EPL) et les cellules stromales mésenchymateuses adipeuses (ASC) i n vitro. Nous avons émis l'hypothèse que les deux produits inhiberaient de manière significative la croissance de Staphylococcus aureus et d'Escherichia coli. Un pool de sang de 10 chevaux a été utilisé pour la production d'EPL. Des cellules stromales mésenchymateuses ont été isolées à partir de tissu adipeux prélevé dans la région fessière de trois chevaux. L'étude a évalué trois groupes de traitement : 10 × EPL, 1,6 million d'ASC et un témoin, en utilisant un design en blocs non équilibrés incomplets avec des mesures répétées. Les lectures de densité optique et les unités formatrices de colonie/mL ont été calculées à 0, 3, 6, 9, 12, 18 et 24 heures. Une diminution de la croissance bactérienne a été observée à plusieurs moments pour les traitements S. aureus-ASC et S. aureus-EPL, soutenant notre hypothèse. Une croissance bactérienne accrue a été remarquée dans le groupe E. coli-EPL, sans différence dans le traitement E. coli-ASC, ce qui s'opposait à notre hypothèse. Une conclusion claire des effets antimicrobiens de l'EPL et des ASC ne peut pas être tirée de cette étude in vitro. Bien qu'il semble que les ASC aient un effet significatif sur la diminution de la croissance de S. aureus, d'autres études sont nécessaires pour explorer ces effets, en particulier chez les bactéries à Gram positif.(Traduit par Docteur Serge Messier).

Nanofat: A therapeutic paradigm in regenerative medicine.

Adipose tissue is a compact and well-organized tissue containing a heterogeneous cellular population of progenitor cells, including mesenchymal stromal cells. Due to its availability and accessibility, adipose tissue is considered a "stem cell depot." Adipose tissue products possess anti-inflammatory, anti-fibrotic, anti-apoptotic, and immunomodulatory effects. Nanofat, being a compact bundle of stem cells with regenerative and tissue remodeling potential, has potential in translational and regenerative medicine. Considering the wide range of applicability of its reconstructive and regenerative potential, the applications of nanofat can be used in various disciplines. Nanofat behaves on the line of adipose tissue-derived mesenchymal stromal cells. At the site of injury, these stromal cells initiate a site-specific reparative response comprised of remodeling of the extracellular matrix, enhanced and sustained angiogenesis, and immune system modulation. These properties of stromal cells provide a platform for the usage of regenerative medicine principles in curbing various diseases. Details about nanofat, including various preparation methods, characterization, delivery methods, evidence on practical applications, and ethical concerns are included in this review. However, appropriate guidelines and preparation protocols for its optimal use in a wide range of clinical applications have yet to be standardized.

Experimental Infection of North American Sheep with Ehrlichia ruminantium.

Ehrlichia ruminantium, a tick-borne rickettsial, causes heartwater in ruminants resulting from vascular damage. Severity of heartwater varies greatly in ruminant species and breeds, age of animals and for diverse geographic E. ruminantium strains. E. ruminantium and a tick vector, Amblyomma variegatum, originating from Africa, are well established in certain Caribbean islands two centuries ago. Besides the possibility of introduction of heartwater through African exotic animal importation, presence of the pathogen, and the tick vector in the Caribbean pose a high risk to ruminants in the USA and other western hemisphere countries. Scientific evidence supporting the heartwater threat to nonendemic regions, however, is lacking. We describe the first infection study in sheep reared in the USA with seven E. ruminantium strains. All infected sheep exhibited clinical signs characteristic of subacute to subclinical disease, which included labored breathing, depression, coughing, and nasal discharges. Gross and microscopic lesions consistent with heartwater disease including edema and hemorrhage were observed in several organs. Pathogen-specific IgG antibody response was detected in animals infected with all seven strains, while molecular analysis confirmed the pathogen presence only when infected with in vitro cultures. This is the first infection study demonstrating severe heartwater in sheep reared in North America.

Angioinvasive lymphoma (lymphomatoid granulomatosis) in a cat, with cutaneous and ocular metastasis.

Lymphomatoid granulomatosis (LYG) is a rare variant of an angioinvasive T-cell lymphoproliferative disorder that primarily affects the lungs, with common sites of metastasis including the skin and subcutis. In humans, it is a B-cell lymphoproliferative disorder associated with Epstein-Barr virus infection. Our case is a 7-y-old, spayed female, domestic longhair cat that decompensated and was euthanized following an initial diagnosis of angioinvasive lymphoma from a skin biopsy. Autopsy revealed nodules in the lungs and subcutis, and corneal thickening and cloudiness. Histologic examination of cutaneous nodules, lungs, and eye showed similar angioinvasive cellular infiltrates and pattern to that of the original skin biopsy, consistent with a diagnosis of LYG. The neoplastic cells displayed CD3-positive immunoreactivity in the skin, eye, and lung, and PCR for antigen receptor rearrangement (PARR) showed T-cell clonality in all tissues tested. This is the third case of LYG to be reported in cats and is the only case in which PARR analysis and immunophenotyping immunohistochemical staining was performed. LYG with ocular involvement has not been reported previously in cats, to our knowledge. Our case demonstrates the necessity for considering LYG when presented with a cat with respiratory signs in conjunction with subcutaneous nodules and ocular lesions.

Bronchoscopically delivered microwave ablation in an in vivo porcine lung model.

BACKGROUND: Percutaneous microwave ablation is clinically used for inoperable lung tumour treatment. Delivery of microwave ablation applicators to tumour sites within lung parenchyma under virtual bronchoscopy guidance may enable ablation with reduced risk of pneumothorax, providing a minimally invasive treatment of early-stage tumours, which are increasingly detected with computed tomography (CT) screening. The objective of this study was to integrate a custom microwave ablation platform, incorporating a flexible applicator, with a clinically established virtual bronchoscopy guidance system, and to assess technical feasibility for safely creating localised thermal ablations in porcine lungs in vivo. METHODS: Pre-ablation CTs of normal pigs were acquired to create a virtual model of the lungs, including airways and significant blood vessels. Virtual bronchoscopy-guided microwave ablation procedures were performed with 24-32 W power (at the applicator distal tip) delivered for 5-10 mins. A total of eight ablations were performed in three pigs. Post-treatment CT images were acquired to assess the extent of damage and ablation zones were further evaluated with viability stains and histopathologic analysis. RESULTS: The flexible microwave applicators were delivered to ablation sites within lung parenchyma 5-24 mm from the airway wall via a tunnel created under virtual bronchoscopy guidance. No pneumothorax or significant airway bleeding was observed. The ablation short axis observed on gross pathology ranged 16.5-23.5 mm and 14-26 mm on CT imaging. CONCLUSION: We have demonstrated the technical feasibility for safely delivering microwave ablation in the lung parenchyma under virtual bronchoscopic guidance in an in vivo porcine lung model.

Multiple Ehrlichia chaffeensis Genes Critical for Its Persistent Infection in a Vertebrate Host Are Identified by Random Mutagenesis Coupled with In Vivo Infection Assessment.

Ehrlichia chaffeensis, a tick-transmitted obligate intracellular rickettsial agent, causes human monocytic ehrlichiosis. In recent reports, we described substantial advances in developing random and targeted gene disruption methods to investigate the functions of E. chaffeensis genes. We reported earlier that the Himar1 transposon-based random mutagenesis is a valuable tool in defining E. chaffeensis genes critical for its persistent growth in vivo in reservoir and incidental hosts. The method also aided in extending studies focused on vaccine development and immunity. Here, we describe the generation and mapping of 55 new mutations. To define the critical nature of the bacterial genes, infection experiments were carried out in the canine host with pools of mutant organisms. Infection evaluation in the physiologically relevant host by molecular assays and by xenodiagnoses allowed the identification of many proteins critical for the pathogen's persistent in vivo growth. Genes encoding proteins involved in biotin biosynthesis, protein synthesis and fatty acid biosynthesis, DNA repair, electron transfer, and a component of a multidrug resistance (MDR) efflux pump were concluded to be essential for the pathogen's in vivo growth. Three known immunodominant membrane proteins, i.e., two 28-kDa outer membrane proteins (P28/OMP) and a 120-kDa surface protein, were also recognized as necessary for the pathogen's obligate intracellular life cycle. The discovery of many E. chaffeensis proteins crucial for its continuous in vivo growth will serve as a major resource for investigations aimed at defining pathogenesis and developing novel therapeutics for this and related pathogens of the rickettsial family Anaplasmataceae.

Pseudocowpox virus infection in an American bison (Bison bison).

BACKGROUND: The present report describes a case of pseudocowpox virus (PCPV) infection in a seven-year-old female bison euthanized due to a history of declining condition and sores on the vulva and udder. CASE PRESENTATION: External examination revealed multifocal, raised, keratinized plaques (0.5-2 cm) covering the skin of the ventral surface of the tail, perineum, caudoventral abdomen, udder, both inguinal recesses, and the medial aspects of both thighs. No significant gross lesions were present in the reminder of the tissues examined. Histopathological examination of the affected skin showed moderate epidermal hyperplasia with rete pegs, marked parakeratotic hyperkeratosis with crusts of degenerate neutrophils and cell debris, and few epithelial cells undergoing ballooning degeneration with occasional eosinophilic intracytoplasmic inclusion bodies (3-5 µm Bollinger body). Negative staining electron microscopy from skin revealed typical Parapoxvirus (PPV) particles, which were also confirmed by real-time PCR (Ct =18.6). Metagenomic analysis of the skin samples revealed only poxviruses. The bison parapox B2L envelope gene clustered with other parapox sequences identified from ruminants. CONCLUSIONS: This is the first report of PCPV virus infection in an American bison. Identification of novel susceptible hosts of parapox viruses sheds light on the viral evolution and highlights the importance of potential economic impact of this disease to the bison industry.

Directional Microwave Ablation: Experimental Evaluation of a 2.45-GHz Applicator in Ex Vivo and In Vivo Liver.

PURPOSE: To experimentally characterize a microwave (MW) ablation applicator designed to produce directional ablation zones. MATERIALS AND METHODS: Using a 14-gauge, 2.45-GHz side-firing MW ablation applicator, 36 ex vivo bovine liver ablations were performed. Ablations were performed at 60 W, 80 W, and 100 W for 3, 5, and 10 minutes (n = 4 per combination). Ablation zone forward and backward depth and width were measured and directivity was calculated as the ratio of forward to backward depth. Thirteen in vivo ablations were performed in 2 domestic swine with the applicator either inserted into the liver (80 W, 5 min, n = 3; 100 W, 5 min, n = 3; 100 W, 10 min, n = 2) or placed on the surface of the liver with a nontarget tissue placed on the back side of the applicator (80 W, 5 min, n = 5). The animals were immediately euthanized after the procedure; the livers were harvested and sectioned perpendicular to the axis of the applicator. In vivo ablation zones were measured following viability staining and assessed on histopathology. RESULTS: Mean ex vivo ablation forward depth was 8.3-15.5 mm. No backward heating was observed at 60 W, 3-5 minutes; directivity was 4.7-11.0 for the other power and time combinations. In vivo ablation forward depth was 10.3-11.5 mm, and directivity was 11.5-16.1. No visible or microscopic thermal damage to nontarget tissues in direct contact with the back side of the applicator was observed. CONCLUSIONS: The side-firing MW ablation applicator can create directional ablation zones in ex vivo and in vivo tissues.

Prostate cancer cell growth characteristics in serum and prostate-conditioned media from moderate-intensity exercise-trained healthy and tumor-bearing rats.

Physical activity is associated with diminished risk of several cancers, and preclinical studies suggest exercise training may alter tumor cell growth in certain tissue(s) (e.g., adipose). From moderate-intensity exercise-trained rats versus sedentary controls, we hypothesized 1) there will be a decreased prostate cancer cell viability and migration in vitro and, within the prostate, a reduced 5α-reductase 2 (5αR2) and increased caspase-3 expression, and 2) that exercise training in tumor-bearing (TB) animals will demonstrate a reduced tumor cell viability in prostate-conditioned media. Serum and prostate were harvested from sedentary or exercise-trained (treadmill running, 10-11 weeks) immune-competent (Copenhagen; n = 20) and -deficient (Nude; n = 18) rats. AT-1 and PC-3 prostate cancer cells were grown in one or more of the following: serum-supplemented media (SSM), SSM from TB rats (SSM-TB), prostate-conditioned media (PCM) or PCM from TB rats (PCM-TB) for 24-96 h under normoxic (18.6% O2) or hypoxic (5% O2) conditions. Under normoxic condition, there was a decreased AT-1 cell viability in SSM and PCM from the exercise-trained (ET) immune-competent rats, but no difference in PC-3 cell viability in SSM and PCM from ET Nude rats versus the sedentary (SED) group, or in SSM-TB from ET-TB Nude rats versus the SED-TB group. However, there was a decreased PC-3 cell viability in the PCM-TB of the ET-TB group versus SED-TB group. PC-3 cell viability in all conditioned media types was not altered between groups with hypoxia. In the prostate, exercise training did not alter 5αR2 expression levels, but increased caspase-3 expression levels. In conclusion, prior exercise status reduced prostate cancer cell viability in the serum and prostate of trained rats but did not modify several other key prostate tumor cell growth characteristics (e.g., migration, cell cycle except in S phase of PC-3 cells in PCM-TB). Importantly, once the tumor was established, exercise training reduced tumor cell viability in the surrounding prostate, which may help explain the reduced severity of the disease in patients that exercise.