The use of equine chondrogenic-induced mesenchymal stem cells as a treatment for osteoarthritis: A randomised, double-blinded, placebo-controlled proof-of-concept study.

BACKGROUND: There is a need to improve therapies for osteoarthritis in horses. OBJECTIVES: To assess the efficacy of equine allogeneic chondrogenic-induced mesenchymal stem cells combined with equine allogeneic plasma as a novel therapy for osteoarthritis in horses. STUDY DESIGN: Randomised, double-blinded, placebo-controlled experiment. METHODS: In 12 healthy horses, osteoarthritis was induced in the metacarpophalangeal joint using an osteochondral fragment-groove model. Five weeks after surgery, horses were randomly assigned to either an intra-articular injection with chondrogenic-induced mesenchymal stem cells + equine allogeneic plasma (= intervention) or with 0.9% saline solution (= control). From surgery until the study end, horses underwent a weekly joint and lameness assessment. Synovial fluid was collected for cytology and biomarker analysis before surgery and at Weeks 5, 5 + 1d, 7, 9 and 11. At Week 11, horses were subjected to euthanasia, and the metacarpophalangeal joints were evaluated macroscopically and histologically. RESULTS: No serious adverse events or suspected adverse drug reactions occurred during the study. A significant improvement in visual and objective lameness was seen with the intervention compared with the control. Synovial fluid displayed a significantly higher viscosity and a significantly lower glycosaminoglycan concentration in the intervention group. Other biomarkers or cytology parameters were not significantly different between the treatment groups. Significantly less wear lines and synovial hyperaemia were present in the intervention group. The amount of cartilage oligomeric matrix protein, collagen type II and glycosaminoglycans were significantly higher in the articular cartilage of the intervention group. MAIN LIMITATIONS: This study assessed the short-term effect of the intervention on a limited number of horses, using an osteoarthritis model. This study also included multiple statistical tests, increasing the risk of type 1 error. CONCLUSIONS: Equine allogeneic chondrogenic-induced mesenchymal stem cells combined with equine allogeneic plasma may be a promising treatment for osteoarthritis in horses. The Summary is available in Spanish - see Supporting Information.

Equine allogeneic chondrogenic induced mesenchymal stem cells: A GCP target animal safety and biodistribution study.

The safety of the intra-articular use of mesenchymal stem cells (MSCs) is scarcely reported. Therefore, the goal of this study was to investigate the safety of a single intra-articular injection with allogeneic chondrogenic induced MSCs combined with equine plasma (=the investigational product: IVP) compared to a saline (0.9% NaCl) placebo control (=control product: CP). Sixteen healthy experimental horses were randomly assigned to receive a single intra-articular injection with either the IVP (n=8) or the CP (n=8) in the left metacarpophalangeal joint. All horses underwent a daily clinical assessment throughout the entire study period of 42days to assess adverse events. Additionally, a local joint assessment and a lameness examination were performed daily during the first two weeks, and weekly the following 4weeks. Blood samples were taken weekly for hematological and biochemical analysis. At the end of the study period, horses of the IVP group were euthanized for a thorough necropsy and to check for biodistribution. Tissue samples of the injected joint were collected for histological examination. In both CP and IVP treated horses a mild transient subjective increase in periarticular temperature and lameness was noted after the intra-articular injection with no significant differences between the treatment groups. No distribution of the cells was found using immunohistochemistry and no ectopic tissue formation or signs of inflammation were found on histology. A single intra-articular injection of allogeneic chondrogenic induced MSCs combined with allogeneic plasma in horses had the same clinical side effects as an intra-articular injection with saline solution.

A quantitative swab is a good non-invasive alternative to a quantitative biopsy for quantifying bacterial load in wounds healing by second intention in horses.

The aim of this study was to evaluate different techniques for diagnosing wound infection in wounds healing by second intention in horses and to assess the effect of a vortex and sonication protocol on quantitative bacteriology in specimens with a histologically confirmed biofilm. In 50 wounds healing by second intention, a clinical assessment, a quantitative swab, a semi-quantitative swab, and a swab for cytology were compared to a quantitative tissue biopsy (reference standard). Part of the biopsy specimen was examined histologically for evidence of a biofilm. There was a significant, high correlation (P<0.001; r=0.747) between the outcome of the quantitative swabs and the quantitative biopsies. The semi-quantitative swabs showed a significant, moderate correlation with the quantitative biopsies (P<0.001; ρ=0.524). Higher white blood cell counts for cytology were significantly associated with lower log10 colony-forming units (CFU) in the wounds (P=0.02). Wounds with black granulation tissue showed significantly higher log10 CFU (P=0.003). Specimens with biofilms did not yield higher bacteriological counts after a vortex and sonication protocol was performed to release bacteria from the biofilm. Based on these findings, a quantitative swab is an acceptable non-invasive alternative to a quantitative biopsy for quantifying bacterial load in equine wounds healing by second intention.

Topical distribution of acyclovir in normal equine skin and equine sarcoids: An in vitro study.

Topical acyclovir application is an owner-friendly treatment for occult equine sarcoids, without the caustic side-effects other topical treatments have. Variable clinical success rates have been described, but it is not known to what rate and extent acyclovir penetrates in and through equine skin from a topical formulation. In the current study, an in vitro Franz diffusion model was used to determine the permeation parameters for a generic 5% acyclovir cetomacrogol cream for both healthy and sarcoid equine skin. The distribution of acyclovir between different layers of both skin types was also evaluated. While acyclovir penetrated through both skin types, significantly less acyclovir permeated to the deep dermis of sarcoid skin (197.62ng/mm(3)) compared to normal skin (459.41ng/mm(3)). Within sarcoid skin samples, significantly higher acyclovir concentrations were found in the epidermis (983.59ng/mm(3)) compared to the superficial dermis (450.02ng/mm(3)) and the deep dermis. At each sample point, significantly more acyclovir permeated to the receptor fluid through normal skin compared to sarcoid skin, which is reflected in the significantly higher permeation parameters of normal skin. Normal skin was found to be more permissive for acyclovir, but even in sarcoid skin, enough acyclovir reached the deep dermis to treat a Herpes simplex virus infection. In the case of equine sarcoids, the treatment is aimed at the Bovine papillomavirus and no information is available on the susceptibility of the DNA polymerase of this virus for acyclovir. Therefore, further research is needed to determine the efficacy of acyclovir to treat equine sarcoids.

Comparison of a new laser beam wound camera and a digital photoplanimetry-based method for wound measurement in horses.

The aim of this study was to compare the accuracy, precision, inter- and intra-operator reliability of a new laser beam (LB) wound camera and a digital photoplanimetry-based (DPB) method for measuring the dimensions of equine wounds. Forty-one wounds were created on equine cadavers. The area, circumference, maximum depth and volume of each wound were measured four times with both techniques by two operators. A silicone cast was made of each wound and served as the reference standard to measure the wound dimensions. The DPB method had a higher accuracy and precision in determining the wound volume compared with the LB camera, which had a higher accuracy in determining the wound area and maximum depth and better precision in determining the area and circumference. The LB camera also had a significantly higher overall inter-operator reliability for measuring the wound area, circumference and volume. In contrast, the DPB method had poor intra-operator reliability for the wound circumference. The LB camera was more user-friendly than the DPB method. The LB wound camera is recommended as the better objective method to assess the dimensions of wounds in horses, despite its poorer performance for the measurement of wound volume. However, if the wound measurements are performed by one operator on cadavers or animals under general anaesthesia, the DPB method is a less expensive and valid alternative.