Raphael Labens

Ex vivo effect of gold nanoparticles on porcine synovial membrane

Gold nanoparticles (AuNPs) have great potential as carriers for local drug delivery and as a primary therapeutic for treatment of inflammation. Here we report on the AuNP-synovium interaction in an ex vivo model of intra-articular application for treatment of joint inflammation. Sheets of porcine femoropatellar synovium were obtained post mortem and each side of the tissue samples was maintained in a separate fluid environment. Permeability to AuNPs of different sizes (5−52 nm) and biomarker levels of inflammation were determined to characterize the ex vivo particle interaction with the synovium. Lipopolysaccharide or recombinant human interleukin-1β were added to fluid environments to assess the ex vivo effect of pro-inflammatory factors on permeability and biomarker levels. The synovium showed size selective permeability with only 5 nm AuNPs effectively permeating the entire tissues’ width. This process was further governed by particle stability in the fluid environment. AuNPs reduced matrix metalloproteinase and lactate dehydrogenase activity and hyaluronic acid concentrations but had no effect on prostaglandin E2 levels. Exposure to pro-inflammatory factors did not significantly affect AuNP permeation or biomarker levels in this model. Results with ex vivo tissue modeling of porcine synovium support an anti-inflammatory effect of AuNPs warranting further investigation.

Precision of a photogrammetric method to perform 3D wound measurements compared to standard 2D photographic techniques in the horse

REASONS FOR PERFORMING STUDY Methods of 3D wound imaging in man play an important role in monitoring of healing and determination of the prognosis. Standard photographic assessments in equine wound management consist of 2D analyses, which provide little quantitative information on the wound bed. HYPOTHESES 3D imaging of equine wounds is feasible using principles of stereophotogrammetry. 3D measurements differ significantly and are more precise than results with standard 2D assessments. METHODS Repeated specialised photographic imaging of 4 clinical wounds left to heal by second intention was performed. The intraoperator variability in measurements due to imaging and 3D processing was compared to that of a standard 2D technique using descriptive statistics and multivariate repeated measures ANOVA. RESULTS Using a custom made imaging system, 3D analyses were successfully performed. Area and circumference measurements were significantly different between imaging modalities. The intraoperator variability of 3D measurements was up to 2.8 times less than that of 2D results. On average, the maximum discrepancy between repeated measurements was 5.8% of the mean for 3D and 17.3% of the mean for 2D assessments. CONCLUSIONS The intraoperator repeatability of 3D wound measurements based on principles of stereophotogrammetry is significantly increased compared to that of a standard 2D photographic technique indicating it may be a useful diagnostic and monitoring tool. POTENTIAL RELEVANCE The equine granulation bed plays an important role in equine wound healing. When compared to 2D analyses 3D monitoring of the equine wound bed allows superior quantitative characterisation, contributing to clinical and experimental investigations by offering potential new parameters.

ELASTOGRAPHIC EVALUATION OF NATURALLY OCCURING TENDON AND LIGAMENT INJURIES OF THE EQUINE DISTAL LIMB.

Compression elastography is an ultrasonographic technique that estimates tissue strain and may have utility in diagnosing and monitoring soft tissue injuries in the equine athlete. Recently, elastography has been proven to be a feasible and repeatable imaging modality for evaluating normal tendons and ligaments of the equine distal forelimb. The purposes of this prospective study were to investigate the ability of elastography to detect spontaneously occurring lesions of equine tendons and ligaments diagnosed with magnetic resonance imaging (MRI) and gray-scale ultrasound (US) and to characterize the differences in the elastographic appearance of acute vs. chronic injuries. Fifty seven horses with a total of 65 lesions were evaluated. Images were assessed quantitatively and qualitatively. Acute lesions were found to be significantly softer (P < 0.0001) than chronic lesions (P < 0.0001) and the stiffness of lesions increased with progression of healing (P = 0.0138). A negative correlation between lesion hypoechogenicity and softness was appreciated with more hypoechoic lesions appearing softer (P = 0.0087) and more hyperechoic regions harder (P = 0.0002). A similar finding occurred with increased signal intensity on short tau inversion recovery (STIR) and proton density (PD) MRI sequences correlating with increased softness on elastography (P = 0.0164). Using US and MRI as references, commonly encountered soft tissue injuries of the equine distal limb could be detected with elastography. However, elastography was limited for detecting small, proximal injuries of the hindlimb proximal suspensory ligament. Elastographic evaluation of equine tendons and ligaments may allow better characterization of lesion chronicity and severity, and sequential examinations may optimize lesion management, rehabilitation, and return to training.

The dilemma of whether to inject the navicular bursa

PALMAR foot pain represents an important condition in horses, frequently requiring a broad therapeutic approach, as summarised in a paper by Manfredi and others (2012) on p 643 of this issue of Veterinary Record . Management options range from supportive treatments, in the form of corrective trimming and remedial shoeing, to systemic and local administration of anti-inflammatories, tiludronate, extracorporeal shock wave therapy or, in the most refractory cases, palmar digital neurectomies (Rijkenhuizen 2006). The key to successful long-term management is knowledge of the exact nature of the condition; palmar foot pain is a clinical sign and not a diagnosis. Often defined by the response of the palmar digital nerves (PDN) to analgesia, many different conditions may fall into this category such that this blocking pattern would more aptly be regarded as an indicator of foot pain instead (Schumacher and others 2004, Dyson and others 2005, Murray and others 2006). To name only a few conditions, horses with lameness due to solar bruises, osteoarthritis/synovitis of the distal interphalangeal (DIP) joint, deep digital flexor (DDF) tendinopathy, navicular bone disease or navicular bursitis typically improve greatly when this nerve block is applied, while a partial response might be achieved in horses with collateral ligament desmitis of the DIP joint and more extensive DDF tendon injuries. Advanced diagnostics (with the gold standard being MRI) are …

Effect of intra-articular administration of superparamagnetic iron oxide nanoparticles (SPIONs) for MRI assessment of the cartilage barrier in a large animal model

Early diagnosis of cartilage disease at a time when changes are limited to depletion of extracellular matrix components represents an important diagnostic target to reduce patient morbidity. This report is to present proof of concept for nanoparticle dependent cartilage barrier imaging in a large animal model including the use of clinical magnetic resonance imaging (MRI). Conditioned (following matrix depletion) and unconditioned porcine metacarpophalangeal cartilage was evaluated on the basis of fluorophore conjugated 30 nm and 80 nm spherical gold nanoparticle permeation and multiphoton laser scanning and bright field microscopy after autometallographic particle enhancement. Consequently, conditioned and unconditioned joints underwent MRI pre- and post-injection with 12 nm superparamagnetic iron oxide nanoparticles (SPIONs) to evaluate particle permeation in the context of matrix depletion and use of a clinical 1.5 Tesla MRI scanner. To gauge the potential pro-inflammatory effect of intra-articular nanoparticle delivery co-cultures of equine synovium and cartilage tissue were exposed to an escalating dose of SPIONs and IL-6, IL-10, IFN-γ and PGE2 were assessed in culture media. The chemotactic potential of growth media samples was subsequently assessed in transwell migration assays on isolated equine neutrophils. Results demonstrate an increase in MRI signal following conditioning of porcine joints which suggests that nanoparticle dependent compositional cartilage imaging is feasible. Tissue culture and neutrophil migration assays highlight a dose dependent inflammatory response following SPION exposure which at the imaging dose investigated was not different from controls. The preliminary safety and imaging data support the continued investigation of nanoparticle dependent compositional cartilage imaging. To our knowledge, this is the first report in using SPIONs as intra-articular MRI contrast agent for studying cartilage barrier function, which could potentially lead to a new diagnostic technique for early detection of cartilage disease.

A Rare Case of Deep Digital Flexor Tendinopathy Following Centesis of the Navicular Bursa

Navicular bursa (NB) centesis is a common diagnostic and therapeutic procedure in equine practice. This case report documents the clinical, diagnostic imaging and histological findings in a horse with a suspected iatrogenic deep digital flexor tendon (DDFT) injury following centesis of the NB via a modified distal plantar approach (placement of two needles in a weight bearing position). Although it cannot be proven with absolute certainty, the authors believe that this is the first reported case where NB centesis is the likely cause of a DDFT lesion, and with magnetic resonance imaging performed both pre- and post-centesis. With this potential, though rare, complication of the procedure, alternative tendon sparing injection techniques should be considered prior to NB centesis in certain cases.

Extracorporeal perfusion of isolated organs of large animals – Bridging the gap between in vitro and in vivo studies

Since the early 20th century, extracorporeal perfusion of large animal organs has been used to investigate a broad variety of research questions, thereby overcoming common drawbacks of in vitro studies without suffering from ethical concerns associated with live animal research. The technique is in accordance with the 3R principles and represents an excellent opportunity to investigate the physiology of organs in detail under standardized conditions. It is also suitable for the translation of basic pre-clinical research into a more relevant arena prior to or avoiding live animal research altogether. Furthermore, organ perfusion has also been an important tool in developing methods of organ preservation for transplantation surgery. Yet, due to the nature of the experiments, only short-term observations can be made and while cells are still exposed to their regional secretome, the whole organ itself is isolated from the body and correlations between organ systems cannot be taken into consideration. This review gives an overview over the history of extracorporeal perfusion of large animal organs and limbs, highlighting major achievements in the field and discussing different experimental set-ups. Advantages and limitations of the technique are presented. Prospective future research perspectives, which may include tracking of specific cell types and study of their distinct behavior towards different stimuli, are given to illustrate the relevance of this method.

Magnetic resonance imaging assisted management in five cases of suspected quittor

OBJECTIVES Assessment of the usefulness of magnetic resonance imaging (MRI) in treatment planning in suspected cases of quittor in the horse. METHODS Five horses with chronic discharging tracts at the level of the foot underwent MRI for treatment planning. RESULTS The MRI examination revealed variable involvement of soft tissue and osseous structures of the foot in addition to abnormalities of the ungular cartilages in all cases. In two cases, follow-up MRI examination was performed. Four of five horses had a successful outcome, with three of these undergoing only one surgical procedure and one being managed medically. CLINICAL SIGNIFICANCE We believe that the use of preoperative MRI facilitated accurate determination of the structures involved in cases of quittor, guiding the management, surgical approach and postoperative therapy.