The lipopolysaccharide model for the experimental induction of transient lameness and synovitis in Standardbred horses

An established lipopolysaccharide (LPS) model previously described in Warmbloods, was inconsistent in Standardbred horses, where lameness was not detected despite the presence of synovitis. The present study aimed to determine the dose of LPS from E. coli O55:B5 required to induce mild to moderate lameness following middle carpal joint injection in Standardbred horses and to quantitate the induced lameness over time, with and without anti-inflammatory pre-treatment. In a baseline trial, eight healthy, clinically sound Standardbred horses were used in a rule-based dose-escalation design trial, starting at a dose of 10 endotoxin units (EU). Lameness at trot was evaluated visually and quantitatively (using an inertial-sensor system and pressure plate analysis). Synovial fluid aspirates were analysed for total nucleated cell counts, total protein and prostaglandin E₂ (PGE₂). Following 2 months wash-out, the effective LPS-dose determined in the baseline trial was used to evaluate the effect of anti-inflammatory treatment. A mixed model for repeated measures with horse as random effect was used for analysis. After injection of 10 EU LPS, the desired degree of lameness was observed in the baseline trial, with maximal lameness at post-injection hour (PIH) 4, followed by a rapid decline and return to baseline by PIH 48. No lameness was observed following pre-treatment with meloxicam. In synovial fluid, PGE₂ was significantly higher at PIH 8 and PIH 24 in the baseline trial compared with following meloxicam pre-treatment. In conclusion, injection of the middle carpal joint with 10 EU LPS consistently induces a transient lameness and synovitis in Standardbred horses.

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.

Long-term results of tenoscopic treatment of lesions in the digital flexor tendon sheath: a retrospective study of fifty horses

Injuries to the structures within the digital flexor tendon sheath (DFTS) can be the primary cause of non-infectious tenosynovitis, for which diagnostic and therapeutic tenoscopy can be performed. In this retrospective study, the medical records of fifty horses that underwent tenoscopic treatment of non-infectious tenosynovitis of the DFTS from 2008 to 2016 at the Faculty of Veterinary Medicine (Ghent University), were evaluated. Telephonic follow-up information was obtained for forty horses. In jumping horses, front limbs were significantly more often involved, whereas in non-jumping horses, the hind limbs were affected more frequently (P=0.01). Lesions of the deep digital flexor tendon (DDFT) were observed in 45% of the cases and lesions of the manica flexoria (MF) in 39% of the cases. Ultimately, 27.7% of horses with lesions of the DDFT and 53% of horses with lesions of the MF returned to their original level of performance, with a mean follow-up period of 4.6 ± 2.5 years.

Can the hoof be shod without limiting the heel movement? A comparative study between barefoot, shoeing with conventional shoes and a split-toe shoe

Conventional shoeing restricts heel movement, which may have a negative effect on the orthopaedic health of the horse. A randomised crossover experimental study using noninvasive techniques was performed to compare the mediolateral heel movement in barefoot horses, horses shod with a conventional toe clipped shoe and with a new type of shoe with a split toe. In eight horses, 16 forelimbs were tested barefoot, shod with a conventional shoe and with the split-toe (ST) shoe, in random order. A displacement sensor was secured on the heels and measurements were collected continuously at a frequency of 679Hz while horses were exercised on a treadmill at the walk (1.8m/s), trot (3.5m/s) and canter (8m/s). Differences in heel movement between the conditions were analysed using a generalised estimating equations approach. The conventional shoe was associated with significantly less heel expansion compared with the ST shoe and barefoot situation in all gaits (P≤0.001). Heel expansion with the ST shoe was not significantly different from the barefoot condition. For all gaits, shoeing was associated with a significant reduction in heel contraction compared with the barefoot situation (P≤0.038), except for the heel contraction at the canter using a conventional shoe. In conclusion, the heel expansion with the ST shoe did not differ significantly from when the horse was barefoot, in contrast with the significant restriction of the heel movement when a conventional shoe was used.

Mouldable, thermoplastic, glue-on frog-supportive shoes change hoof kinetics in normal and obese Shetland ponies

Background

Obesity and hyperinsulinaemia are frequently encountered in the equine population and risk factors for the development of laminitis. There are many options for hoof support that claim a beneficial effect, but often the scientific evidence is scarce.

Objectives

To quantify the effect of frog‐supportive shoes on hoof kinetics in normal and obese ponies.

Study design

Controlled in vivo trial.

Methods

Ten Shetland mares (n = 10) with a normal (n = 5) or obese (n = 5) body condition were led over a dynamically calibrated pressure plate before (T0), immediately after (T1) and 72 h (T2) after application of the shoes. The following locomotor variables were measured: stance duration (StDur), vertical impulse (VI), peak vertical force (PVF), time to PVF and time from PVF to lift off. The hoof print was divided into a toe and heel region and the StDur toe–heel index was calculated. The toe–heel hoof balance curves of the vertical force were plotted throughout the stance phase.

Results

The VI and PVF increased significantly 72 h after application of the shoes, when compared with T0 and T1. The StDur toe–heel index and toe–heel balance curves were significantly different between the normal and obese ponies. These variables became more comparable between the groups after application of the frog‐supportive shoes.

Main limitations

It would have been interesting to measure the effect of the shoe in patients with acute laminitis. However, this would have had major welfare implications.

Conclusions

The obese ponies moved more carefully than the normal group, demonstrated by a decreased loading of the toe area. The data illustrate that the ponies became more comfortable 72 h after application of the shoes, with a pronounced effect in the obese group. Thus, these results suggest that frog‐supportive shoes could be beneficial, especially for obese ponies.

Acute instability of the nuchal ligament following cervical neuromuscular dysfunction in a dressage horse

A ten-year-old Warmblood dressage gelding was presented with acute instability of the nuchal ligament after paddock turnout. Based on the clinical signs, orthopedic and neurologic examination, diagnostic imaging and electromyography, cervical neuromuscular dysfunction of the M. obliquus capitis caudalis on the right side of the neck was diagnosed. Conservative treatment including steroidal anti-inflammatory medication in combination with oral supplementation with vitamin B1 and box rest resulted in complete recovery of the horse within six months.

Biomechanische aspecten met betrekking tot hoefbeslag bij paarden

In dit artikel wordt een overzicht gegeven van de huidige biomechanische inzichten die nuttige aanwijzingen kunnen verschaffen voor “evidence-based” keuzes omtrent het bekappen en/of het aanbrengen van hoefbeslag in de behandeling van kreupelheid bij het paard. De nadruk wordt gelegd op een optimale hoefbalans, de absorptie van schokken, de gepaste mate van grip/afremmen versus glijden, optimale drukverdeling binnen de hoef, en het bevorderen van “breakover”. Ook met het hoefmechanisme moet rekening gehouden worden. Ideaal gezien worden de meeste van deze principes reeds gecombineerd in de preventie van letsels.

Evaluation of direct Etest for antimicrobial susceptibility testing of bacteria isolated from synovial fluid of horses using enrichment bottles

This study evaluated the Etest for direct antimicrobial susceptibility testing (AST) of bacteria from equine synovial specimens, incubated in BACTEC enrichment bottles. Ninety-four culture-positive broths were inoculated onto agar to directly determine the minimum inhibitory concentrations (MICs) of 13 antimicrobials, using the Etest (direct Etest). Results were compared with those obtained with the agar dilution reference method, the standard Etest, and the disc diffusion method, after subculture and standardisation of the inoculum. For categorical comparison of AST results, MICs were translated into susceptibility categories, using clinical breakpoints. The direct Etest predicted categorical susceptibility/resistance of bacteria from equine synovial fluid with acceptable accuracy (overall categorical agreement, 91%) and was more reliable than the disc diffusion test. The direct Etest was less accurate than the standard Etest for generating MICs ± 1 log dilution relative to the reference method (overall essential agreement, 69% vs. 89%). As the Etest generated a high percentage of inaccuracies with trimethoprim and sulfadiazine, these were less suitable antimicrobial agents for inclusion. In conclusion, the direct Etest reliably predicted the susceptibility of isolates from equine synovial fluid for the tested antimicrobials, except for trimethoprim and sulfadiazine. Since it did not require subculture and preparation of a standardised inoculum, direct Etest results were available at least 24 h earlier than with other methods, which could facilitate the diagnosis of synovial infections. However, when accuracy is prioritised over speed for MIC determination, the standard Etest is preferred over the direct Etest.

Congenital cutaneous fibropapillomatosis in a warmblood foal

In this report, clinical and histological findings of a rare case of a large congenital fibropapilloma on the forehead of a warmblood foal are reported. Surgical excision was curative and no recurrence was observed after nine months. The foal did not present any other abnormalities. Morphologically, the lesion was classified as a fibro-epithelial type of skin hamartoma. The fibrous component has thus far only been reported in pigs. Although fibropapillomas are common in adult animals and are associated with papillomavirus infection, this association has not been demonstrated in foals and piglets. Additionally, there were no histopathological indications of papillomavirus infection in the present study, nor could PCR reveal the presence of papillomavirus DNA.

The preventive effects of two nutraceuticals on experimentally induced acute synovitis

BACKGROUND

Nutraceuticals are often used in the management of equine osteoarthritis, but scientific evidence of their efficacy is lacking.

OBJECTIVES

To study the preventive effects of two new nutraceuticals after the experimental induction of synovitis in comparison with positive and negative control treatments.

STUDY DESIGN

Blinded, controlled, randomised experiment.

METHODS

Twenty-four healthy Standardbred horses were randomly allocated to supplement AT (multi-ingredient, 28 days), supplement HP (collagen hydrolysate, 60 days), meloxicam (4 days) or placebo (60 days). Synovitis was induced in the right intercarpal joint by intra-articular injection of 0.5 ng lipopolysaccharide (LPS) of Escherichia coli while treatments were continued. Blood and synovial fluid were sampled before treatment, immediately prior to LPS injection, and at 8, 24 and 48 h post-injection. Synovial fluid samples were analysed for total nucleated cell count (TNCC), total protein (TP) and selected biomarkers (prostaglandin E₂ [PGE₂ ], interleukin-6 [IL-6], glycosaminoglycans [GAGs], type II collagen synthesis [CPII], matrix metalloproteinase [MMP]). Lameness was scored by visual examination and pressure plate analysis immediately prior to LPS injection, and at 8, 24 and 48 h post-injection. Clinical examinations were performed before treatment, immediately prior to LPS injection, at 2, 4 and 6 h post-injection, and then twice per day during the test period.

RESULTS

Before treatment and intra-articular challenge, there were no statistically significant differences among the treatment groups for any of the parameters. After intra-articular challenge, the placebo group showed significantly higher synovial fluid TP, TNCC and PGE₂ compared with the meloxicam group, although the model did not induce a relevant amount of lameness. Both nutraceuticals resulted in significantly lower synovial fluid TP, TNCC and PGE₂ compared with placebo. No statistical differences in IL-6, GAGs, CPII or MMPs were observed among treatment groups. No adverse effects were observed.

MAIN LIMITATIONS

Despite evidence of synovitis, lameness was too mild to detect.

CONCLUSIONS

The preventive administration of these nutraceuticals showed anti-inflammatory effects in this validated synovitis model. Therefore, further studies of their clinical applicability are warranted.

Anatomical Description of the Presence and Variability of the Digital Manica Flexoria in the Equine Digital Flexor Tendon Sheath

During endoscopy (tenoscopy) of the distal aspect of the equine digital flexor tendon sheath (DFTS), the digital manica flexoria can be visualized connecting the distal branches of the superficial digital flexor tendon. However, this structure has been inconsistently described and variably named in the veterinary literature. The objectives of this study were to describe the presence, configuration and variability of the digital manica flexoria in the equine distal limb. Dissection of 144 equine cadaveric limbs revealed the presence of this structure in all the feet, although different types and conformations were identified. In the forelimbs, a membranous digital manica flexoria predominated (94%; P < 0.001), in particular a synovial bridge type (83%; P < 0.001). In the hindlimbs, a tendinous digital manica flexoria predominated (93%; P < 0.001), in particular the oblique-crossing of tendinous bundles (61%; P < 0.001). Passage dorsal to the digital manica flexoria towards the distal DFTS was only possible in 22 of the 144 limbs, all forelimbs. Clinicians should be aware of the intra- and inter-individual anatomical variations of the digital manica flexoria to avoid misinterpretation during ultrasonographic and tenoscopic examinations of the DFTS.

Treatment of acquired flexural deformity of the distal interphalangeal joint in the horse: a retrospective study of 51 cases

Flexural deformity of the distal interphalangeal joint is an important disorder in horses, which can be acquired during the first year of life, often as a result of lateralization during grazing. In this retrospective study, the medical files of 51 cases presented at the Faculty of Veterinary Medicine of Ghent University (1999-2013) were analyzed, followed by a telephone questionnaire. In 65% of the conservatively treated patients, the hoof conformation corrected completely, which was not significantly different from what was seen in the surgically treated group (complete correction in 56% of cases). Foals treated conservatively before the age of six months and foals treated surgically before twelve months of age, had a significantly better chance of a successful correction than older foals. Moreover, cases in which treatment did not restore the hoof conformation completely, presented a significantly higher chance of (persisting) lameness and were significantly less likely to have an athletic career. Finally, this study proved a significant association between the hoof conformation of the dam and her foals.

Diffusion of mepivacaine to adjacent synovial structures after intrasynovial analgesia of the digital flexor tendon sheath

REASONS FOR PERFORMING STUDY

Controversy exists about the specificity of diagnostic analgesia of the digital flexor tendon sheath (DFTS) in horses.

OBJECTIVES

To evaluate the degree of diffusion of mepivacaine from the equine DFTS to adjacent synovial structures.

STUDY DESIGN

Crossover experiment.

METHODS

Under general anaesthesia, the DFTS of one front and one hindlimb of 8 horses were injected simultaneously with mepivacaine. Synovial fluid samples of the injected DFTS, the adjacent metacarpo-/metatarsophalangeal (MCP/MTP) joint, proximal interphalangeal joint, distal interphalangeal joint, navicular bursa and contralateral MCP/MTP joint were collected 15 min post injection (T15) from one of the injected limbs and 60 min post injection (T60) from the other limb. Venous blood samples were obtained at T0, T15 and T60 to evaluate systemic distribution of mepivacaine. After a 2-week washout period, the procedure was repeated using the same limbs but reversing the time of sampling (front vs. hindlimbs). The concentration of mepivacaine in samples was measured with a commercial ELISA kit.

RESULTS

Mepivacaine concentrations in the DFTS samples, at both T15 (5077 mg/l) and T60 (3503 mg/l), exceeded those estimated sufficient to produce synovial analgesia (100 mg/l or 300 mg/l). Mepivacaine was found in all synovial structures adjacent to the injected DFTS and in the contralateral MCP/MTP joints, but concentrations were low, with a maximum value of only 3.2 mg/l. With the exception of the navicular bursa samples, the mepivacaine concentrations in the adjacent synovial structures were significantly higher at T60 than at T15 (P<0.03). Significantly higher mepivacaine concentrations were found in the ipsilateral than the contralateral MCP/MTP joints at T60 (P<0.001). Blood samples had significantly higher mepivacaine concentrations at T15 and T60 than at T0 (P<0.001).

CONCLUSIONS

Mepivacaine injected into the DFTS of horses diffuses towards adjacent synovial structures without achieving clinically relevant concentrations.

Chronic progressive lymphedema in the Belgian draft horse in Belgium: clinical phenotyping, prevalence and risk factor analysis

Chronic progressive lymphedema (CPL) is a well-known problem in the Belgian draft horse. However, tools for clinical diagnosis have not been standardized. Therefore, the exact disease prevalence and the possible CPL risk factors have not been investigated in the Belgian breed yet. The aim of the present study was to assess a uniform CPL clinical examination method to increase diagnostic objectivity as well as to determine the occurrence and severity of lesions. Using univariate and stepwise multivariable logistic regression models, the association of factors, such as age-gender interaction, coat color and season, with CPL occurrence was examined. In this study, it was demonstrated that CPL is highly prevalent in the Belgian draft horse: 60.66% of the horses of the total sample were affected, including a large proportion of young horses (< 3 years), whereas 85.86% was affected in a subset of older horses (≥ 3 years). In the latter, the lesions were more explicit as CPL is a chronic disorder. In some horses (i.e. 14% of the yearlings), mild clinical symptoms appeared at approximately the age of one, while distinct onset of the disease occurred from the age of three onwards. The factors age-gender interaction, coat color and season, which are significantly associated with CPL occurrence, were identified and quantified. In this study, a standardized diagnostic protocol is proposed that will enhance future data collection and furthermore will offer a foundation for quantitative genetic research. Ultimately, it will help to reduce CPL occurrence in the Belgian draft horse by means of selection.

Vraag & Antwoord

Anesthetica voor een keizersnede bij de teef Het gebruik van gabapentine bij paarden Urticaria bij het paard

Tenosynovitis van de sesamschede bij het paard: diagnostiek en behandeling

Clinici worden vaak geconfronteerd met kreupele paarden die een opzetting van de sesamschede vertonen. De sesamschede is echter een relatief complexe synoviale structuur die diverse uitdagingen biedt op het gebied van diagnostiek en behandeling van letsels. In dit artikel wordt een overzicht gegeven van de diagnostische en therapeutische aspecten van niet-infectieuze tenosynovitis van de sesamschede.

Vraag & Antwoord

Hematogene infectieuze fysitis bij een veulen Invloed van leeftijd op de spermakwaliteit van de reu Antimicrobiële resistentie bij kalveren met diarree

Treatment of equine degenerative joint disease with autologous peripheral blood-derived mesenchymal stem cells: a case report

A 5-year-old German Warmblood stallion with chronic lameness, attributable to degenerative joint disease (DJD) of the pastern joint unresponsive to medical treatments, was treated with autologous mesenchymal stem cells (MSC). These MSC were isolated from the peripheral blood (PB) of the patient and injected into the pastern joint, at a concentration of 2.5x106 cells, twice with an 8-week interval. The positive response to this stem cell treatment was documented by visual gait evaluation as well as objective pressure plate analyses. This paper is the first to describe the use of autologous PB-derived MSC to treat a horse suffering from chronic DJD. The favorable outcome of this single case may stimulate further research on the use of equine peripheral blood as a source of autologous MSC in equine regenerative medicine.