Identification of 3 neutralizing linear epitopes on the VP8 outer capsid protein of group A equine rotavirus.

OBJECTIVE: To identify protective equine rotavirus group A (ERVA) VP8 epitopes and demonstrate that immunizing hens with synthetic peptides based on these epitopes would yield high-titered, neutralizing egg yolk antibodies for potential application in foals. ANIMALS: 26 rotavirus-positive, client-owned foals were included in the study. Five white leghorn hens were used for antibody production. METHODS: Chicken antibodies were raised against 3 synthetic epitope peptides from the VP8 protein of the common ERVA P-type, P4[12] using CD40-targeted streptavidin-peptide complexes. Antipeptide serum- and egg yolk antibodies were subject to ELISA and in vitro virus neutralization assays to evaluate binding and neutralization activities. Lyophilized anti-VP8 egg yolk antibodies were orally administered (30 g; q 24 h for 5 days) to foals with rotaviral diarrhea. Physical examinations were performed daily. The duration of diarrhea and any adverse effects were recorded. RESULTS: CD40-targeted vaccination of hens generated high titers of anti-VP8 serum and egg yolk antibodies after just 3 immunizations. These antibodies prevented in vitro infection of ERVA with titers of 128 in the serum and 94.5 in the yolk. Oral administration (30 g; q 24 h for 5 days) of lyophilized hyperimmune egg yolk to foals with rotaviral diarrhea did not reveal any adverse effects of the treatment. CLINICAL RELEVANCE: This study demonstrated that antibodies raised against neutralizing epitopes of the ERVA VP8 protein could prevent ERVA infection in vitro. Based on these results and previous work in other animals, in vivo evaluation of the therapeutic efficacy of anti-VP8 egg yolk antibodies is warranted.

Impact of surface receptors TLR2, CR3, and FcγRIII on Rhodococcus equi phagocytosis and intracellular survival in macrophages.

The virulence-associated protein A (VapA) produced by virulent Rhodococcus equi allows it to replicate in macrophages and cause pneumonia in foals. It is unknown how VapA interacts with mammalian cell receptors, but intracellular replication of avirulent R. equi lacking vapA can be restored by supplementation with recombinant VapA (rVapA). Our objectives were to determine whether the absence of the surface receptors Toll-like receptor 2 (TLR2), complement receptor 3 (CR3), or Fc gamma receptor III (FcγRIII) impacts R. equi phagocytosis and intracellular replication in macrophages, and whether rVapA restoration of virulence in R. equi is dependent upon these receptors. Wild-type (WT) murine macrophages with TLR2, CR3, or FcγRIII blocked or knocked out (KO) were infected with virulent or avirulent R. equi, with or without rVapA supplementation. Quantitative bacterial culture and immunofluorescence imaging were performed. Phagocytosis of R. equi was not affected by blockade or KO of TLR2 or CR3. Intracellular replication of virulent R. equi was not affected by TLR2, CR3, or FcγRIII blockade or KO; however, avirulent R. equi replicated in TLR2-/- and CR3-/- macrophages but not in WT and FcγRIII-/-. rVapA supplementation did not affect avirulent R. equi phagocytosis but promoted intracellular replication in WT and all KO cells. By demonstrating that TLR2 and CR3 limit replication of avirulent but not virulent R. equi and that VapA-mediated virulence is independent of TLR2, CR3, or FcγRIII, our study provides novel insights into the role of these specific surface receptors in determining the entry and intracellular fate of R. equi.

Equine bronchial epithelial cells are susceptible to cell entry with a SARS-CoV-2 pseudovirus but reveal low replication efficiency.

OBJECTIVE: To examine the susceptibility of cultured primary equine bronchial epithelial cells (EBECs) to a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pseudovirus relative to human bronchial epithelial cells (HBECs). SAMPLE: Primary EBEC cultures established from healthy adult horses and commercially sourced human bronchial epithelial cells (HBECs) were used as a positive control. METHODS: Angiotensin-converting enzyme 2 (ACE2) expression by EBECs was demonstrated using immunofluorescence, western immunoblot, and flow cytometry. EBECs were transduced with a lentivirus pseudotyped with the SARS-CoV-2 spike protein that binds to ACE2 and expresses the enhanced green fluorescent protein (eGFP) as a reporter. Cells were transduced with the pseudovirus at a multiplicity of infection of 0.1 for 6 hours, washed, and maintained in media for 96 hours. After 96 hours, eGFP expression in EBECs was assessed by fluorescence microscopy of cell cultures and quantitative PCR. RESULTS: ACE2 expression in EBECs detected by immunofluorescence, western immunoblotting, and flow cytometry was lower in EBECs than in HBECs. After 96 hours, eGFP expression in EBECs was demonstrated by fluorescence microscopy, and mean ΔCt values from quantitative PCR were significantly (P < .0001) higher in EBECs (8.78) than HBECs (3.24) indicating lower infectivity in EBECs. CLINICAL RELEVANCE: Equine respiratory tract cells were susceptible to cell entry with a SARS-CoV-2 pseudovirus. Lower replication efficiency in EBECs suggests that horses are unlikely to be an important zoonotic host of SARS-CoV-2, but viral mutations could render some strains more infective to horses. Serological and virological monitoring of horses in contact with persons shedding SARS-CoV-2 is warranted.

A Randomized, Self-Controlled Case Series Evaluating Core Osteostixis of Osseous Cyst-Like Lesions of the Navicular Bone to Improve Lameness in Horses with Podotrochlear Syndrome.

Introduction: Podotrochlear syndrome is a common cause of lameness in Quarter Horses involving both soft tissue and bony structures within the heel region. Current surgical treatment of podotrochlear syndrome addresses pathological changes affecting the soft tissue structures of the navicular region but does not address either edema or cyst-like lesions of the navicular bone. Objective: The objective of this randomized, self-controlled case series was to determine whether core osteostixis improved lameness in Quarter Horses with podotrochlear syndrome characterized by bilateral magnetic resonance imaging (MRI) findings of osseous cyst-like lesions of the navicular bone. Methods: Seven Quarter Horses that had not responded to standard medical management were included. Each horse had an affected forefoot randomly assigned to surgical treatment with navicular bursoscopy and core osteostixis; the contralateral limb was assigned to navicular bursoscopy only. Video recordings were used to assign lameness scores and make comparisons of each limb at baseline and 24 weeks post-operatively by an observer blinded to the surgical treatment. A second MRI was performed 24 weeks after surgery to reevaluate navicular bone edema, osseous cyst-like lesions of the navicular bone, and tears of the deep digital flexor tendon (DDFT). Results: Reduction of lameness score from baseline was significantly (P = 0.0254) greater for the limbs treated with core osteostixis than limbs treated with bursoscopy. New DDFT tears were noted in 3 of 7 limbs treated with core osteostixis and in 1 of 7 bursoscopy limbs. Conclusion: Results of this study suggest that core osteostixis of the navicular bone combined with navicular bursoscopy can improve lameness in horses with osseous cyst-like lesions. Further evaluation of this technique is warranted.

Conservation of vaccine antigen sequences encoded by sequenced strains of Streptococcus equi subsp. equi.

BACKGROUND: Streptococcus equi subspecies equi (S equi) is the cause of Strangles, one of the most prevalent diseases of horses worldwide. Variation within the immunodominant SeM protein has been documented, but a new eight-component fusion protein vaccine, Strangvac, does not contain live S equi or SeM and conservation of the antigens it contains have not been reported. OBJECTIVE: To define the diversity of the eight Strangvac antigens across a diverse S equi population. STUDY DESIGN: Genomic description. METHODS: Antigen sequences from the genomes of 759 S equi isolates from 19 countries, recovered between 1955 and 2018, were analysed. Predicted amino acid sequences in the antigen fragments of SEQ0256(Eq5), SEQ0402(Eq8), SEQ0721(EAG), SEQ0855(SclF), SEQ0935(CNE), SEQ0999(IdeE), SEQ1817(SclI) and SEQ2101(SclC) in Strangvac and SeM were extracted from the 759 assembled genomes and compared. RESULTS: The predicted amino acid sequences of SclC, SclI and IdeE were identical across all 759 genomes. CNE was truncated in the genome of five (0.7%) isolates. SclF was absent from one genome and another encoded a single amino acid substitution. EAG was truncated in two genomes. Eq5 was truncated in four genomes and 123 genomes encoded a single amino acid substitution. Eq8 was truncated in three genomes, one genome encoded four amino acid substitutions and 398 genomes encoded a single amino acid substitution at the final amino acid of the Eq8 antigen fragment. Therefore, at least 1579 (99.9%) of 1580 amino acids in Strangvac were identical in 743 (97.9%) genomes, and all genomes encoded identical amino acid sequences for at least six of the eight Strangvac antigens. MAIN LIMITATIONS: Three hundred and seven (40.4%) isolates in this study were recovered from horses in the UK. CONCLUSIONS: The predicted amino acid sequences of antigens in Strangvac were highly conserved across this collection of S equi.

Wound swabs versus biopsies to detect methicillin resistant Staphylococcus aureus in experimental equine wounds.

OBJECTIVE: To compare: (1) the load and diversity of cultivatable bacterial species isolated from tissue biopsies with cultures from surface swabs, and (2) the ability of each technique to detect methicillin-resistant Staphylococcus aureus (MRSA) in a model of MRSA-infected equine wounds. STUDY DESIGN: Experimental in vivo study. ANIMALS: Three light-breed adult horses. METHODS: Four 2.5 × 2.5 cm full-thickness skin wounds were created on the dorsolateral aspect of each forelimb. Five days later, each wound was inoculated with a pure culture of MRSA (ATCC 43300). One hundred microlitres of 0, 5 × 108 , 5 × 109 or 5 × 1010 colony forming units (CFU)/ml was used to inoculate each wound. Surface swabs (Levine technique) and tissue biopsy samples (3 mm punch biopsy) were obtained at 2, 7, 14, and 21 days after inoculation. Quantitative aerobic culture was performed using routine clinical techniques. RESULTS: A similar bacterial profile was identified from the culture of each wound-sampling technique and there was moderate correlation (R = 0.49, P < .001) between the bacterial bioburdens. Agreement was fair (κ = 0.31; 95% CI, 0.129-0.505) between the sampling techniques in identification of MRSA. Methicillin-resistant Staphylococcus aureus was isolated more frequently (P = .016) from cultures of tissue biopsies (79%; 76/96) than from surface swabs (62%; 60/96). CONCLUSION: Bacterial load and diversity did not differ between sampling techniques but MRSA was detected more often from the cultures of tissue biopsies. CLINICAL SIGNIFICANCE: Tissue biopsy should be preferred to culture swab in wounds where MRSA is suspected.

The opportunistic intracellular bacterial pathogen Rhodococcus equi elicits type I interferon by engaging cytosolic DNA sensing in macrophages.

Rhodococcus equi is a major cause of foal pneumonia and an opportunistic pathogen in immunocompromised humans. While alveolar macrophages constitute the primary replicative niche for R. equi, little is known about how intracellular R. equi is sensed by macrophages. Here, we discovered that in addition to previously characterized pro-inflammatory cytokines (e.g., Tnfa, Il6, Il1b), macrophages infected with R. equi induce a robust type I IFN response, including Ifnb and interferon-stimulated genes (ISGs), similar to the evolutionarily related pathogen, Mycobacterium tuberculosis. Follow up studies using a combination of mammalian and bacterial genetics demonstrated that induction of this type I IFN expression program is largely dependent on the cGAS/STING/TBK1 axis of the cytosolic DNA sensing pathway, suggesting that R. equi perturbs the phagosomal membrane and causes DNA release into the cytosol following phagocytosis. Consistent with this, we found that a population of ~12% of R. equi phagosomes recruits the galectin-3,-8 and -9 danger receptors. Interestingly, neither phagosomal damage nor induction of type I IFN require the R. equi's virulence-associated plasmid. Importantly, R. equi infection of both mice and foals stimulates ISG expression, in organs (mice) and circulating monocytes (foals). By demonstrating that R. equi activates cytosolic DNA sensing in macrophages and elicits type I IFN responses in animal models, our work provides novel insights into how R. equi engages the innate immune system and furthers our understanding how this zoonotic pathogen causes inflammation and disease.

Safe and effective aerosolization of in vitro transcribed mRNA to the respiratory tract epithelium of horses without a transfection agent.

Vaccines and therapeutics using in vitro transcribed mRNA hold enormous potential for human and veterinary medicine. Transfection agents are widely considered to be necessary to protect mRNA and enhance transfection, but they add expense and raise concerns regarding quality control and safety. We found that such complex mRNA delivery systems can be avoided when transfecting epithelial cells by aerosolizing the mRNA into micron-sized droplets. In an equine in vivo model, we demonstrated that the translation of mRNA into a functional protein did not depend on the addition of a polyethylenimine (PEI)-derived transfection agent. We were able to safely and effectively transfect the bronchial epithelium of foals using naked mRNA (i.e., mRNA formulated in a sodium citrate buffer without a delivery vehicle). Endoscopic examination of the bronchial tree and histology of mucosal biopsies indicated no gross or microscopic adverse effects of the transfection. Our data suggest that mRNA administered by an atomization device eliminates the need for chemical transfection agents, which can reduce the cost and the safety risks of delivering mRNA to the respiratory tract of animals and humans.

Opsonization but not pretreatment of equine macrophages with hyperimmune plasma nonspecifically enhances phagocytosis and intracellular killing of Rhodococcus equi.

BACKGROUND: Evidence regarding the efficacy of equine hyperimmune plasma to prevent pneumonia in foals caused by Rhodococcus equi is limited and conflicting. HYPOTHESIS: Opsonization with R. equi-specific hyperimmune plasma (HIP) will significantly increase phagocytosis and decrease intracellular replication of R. equi by alveolar macrophages (AMs) compared to normal plasma (NP). ANIMALS: Fifteen adult Quarter Horses were used to collect bronchoalveolar lavage cells. METHODS: In the first experiment, AMs from 9 horses were pretreated (incubated) with either HIP, NP, or media only (control) and then infected with nonopsonized R. equi. In a second experiment, AMs from 6 horses were infected with R. equi either opsonized with HIP or opsonized with NP. For both experiments, AMs were lysed at 0 and 48 hours and the number of viable R. equi quantified by culture were compared among groups using linear mixed-effects modeling with significance set at P < .05. RESULTS: Opsonization with either HIP or NP increased phagocytosis by AMs (P < .0001) and decreased intracellular survival of organisms in AMs (P < .0001). Pretreating AMs with either HIP or NP without opsonizing R. equi had no effects on phagocytosis or intracellular replication. CONCLUSIONS AND CLINICAL IMPORTANCE: Opsonizing R. equi with either NP or HIP decreases intracellular survival of organisms in AMs, but the effect does not appear to be enhanced by using HIP. Mechanisms other than effects on AMs must explain any clinical benefits of using HIP over NP to decrease the incidence of R. equi pneumonia in foals.

Randomized, controlled clinical trial to assess the effect of antimicrobial-impregnated suture on the incidence of surgical site infections in dogs and cats.

OBJECTIVE: To evaluate the prophylactic efficacy of triclosan-coated (TC) suture in preventing surgical site infections (SSIs) in dogs and cats undergoing surgical procedures. ANIMALS: 862 animals (794 dogs and 68 cats). PROCEDURES: Incidences of SSI of surgical wounds closed with TC suture and surgical wounds closed with non-TC suture occurring between the time of surgery and 1 month postoperatively were compared. Animals were randomly assigned to TC or non-TC suture groups. When TC suture was assigned, all suture available as TC material was used rather than non-TC suture. Presence of an SSI was determined by an owner questionnaire or direct examination. RESULTS: Overall, 50 of 862 (5.8%) animals developed SSIs. Incidence of SSI was 6% (24/428) in the non-TC suture group and 6% (26/434) in the TC suture group. No significant difference was found in the incidence of SSI between groups. No significant difference was detected in the incidence of incisional problems (eg, redness, dehiscence, and seroma formation) between animals in which TC suture was used and those in which non-TC suture was used. On multivariable analysis, other factors were associated with increased SSI rates, including an incision length > 10 cm, surgery performed by the soft tissue surgery department, and anesthesia duration of > 240 minutes. CONCLUSIONS AND CLINICAL RELEVANCE: No significant difference in incidence of SSI was detected between animals undergoing surgical procedures performed with non-TC versus TC suture.

Non-invasive evaluation of the equine gastrointestinal mucosal transcriptome.

Evaluating the health and function of the gastrointestinal tract can be challenging in all species, but is especially difficult in horses due to their size and length of the gastrointestinal (GI) tract. Isolation of mRNA of cells exfoliated from the GI mucosa into feces (i.e., the exfoliome) offers a novel means of non-invasively examining the gene expression profile of the GI mucosa. This approach has been utilized in people with colorectal cancer. Moreover, we have utilized this approach in a murine model of GI inflammation and demonstrated that the exfoliome reflects the tissue transcriptome. The ability of the equine exfoliome to provide non-invasive information regarding the health and function of the GI tract is not known. The objective of this study was to characterize the gene expression profile found in exfoliated intestinal epithelial cells from normal horses and compare the exfoliome data with the tissue mucosal transcriptome. Mucosal samples were collected from standardized locations along the GI tract (i.e. ileum, cecum, right dorsal colon, and rectum) from four healthy horses immediately following euthanasia. Voided feces were also collected. RNA isolation, library preparation, and RNA sequencing was performed on fecal and intestinal mucosal samples. Comparison of gene expression profiles from the tissue and exfoliome revealed correlation of gene expression. Moreover, the exfoliome contained reads representing the diverse array of cell types found in the GI mucosa suggesting the equine exfoliome serves as a non-invasive means of examining the global gene expression pattern of the equine GI tract.

NSAIDs disrupt intestinal homeostasis by suppressing macroautophagy in intestinal epithelial cells.

Small intestinal damage induced by nonsteroidal anti-inflammatory drugs (NSAIDs) remains an under-recognized clinical disorder. The incomplete understanding of the pathophysiology has hampered the development of prevention and treatment strategies leading to the high morbidity and mortality rates. NSAIDs are known to modulate macroautophagy, a process indispensable for intestinal homeostasis. Whether NSAIDs stimulate or repress macroautophagy and how this correlates with the clinical manifestations of NSAID enteropathy, however, remains unknown. The objectives of this study were to determine whether NSAIDs impaired macroautophagy and how this affects macroautophagy-regulated intestinal epithelial cell (IEC) processes essential for intestinal homeostasis (i.e., clearance of invading pathogens, secretion and composition of mucus building blocks, and inflammatory response). We show that NSAID treatment of IECs inhibits macroautophagy in vitro and in vivo. This inhibition was likely attributed to a reduction in the area and/or distribution of lysosomes available for degradation of macroautophagy-targeted cargo. Importantly, IEC regulatory processes necessary for intestinal homeostasis and dependent on macroautophagy were dysfunctional in the presence of NSAIDs. Since macroautophagy is essential for gastrointestinal health, NSAID-induced inhibition of macroautophagy might contribute to the severity of intestinal injury by compromising the integrity of the mucosal barrier, preventing the clearance of invading microbes, and exacerbating the inflammatory response.

A Thoroughbred racehorse with a unicortical palmar lateral condylar fracture returned to training 14 days after surgery: a hypothesis on the role of a single bone screw on crack propagation.

A 2-year-old Thoroughbred racehorse had LF lameness that began post high-speed exercise and persisted for two days before the horse once again became sound. Diagnostic analgesia localized the lameness to the LF distal metacarpus, and a standing MRI identified a unicortical condylar fracture. A single 5.5 mm cortical screw was placed in lag fashion. The horse began hand walking at 14 days, racetrack jogging at 30 days, and racing at 5 months after the day of surgery. Placement of a single lag screw ahead of the tip of the crack in unicortical condylar fracture may be useful for reducing the recovery period for horses returning to training and racing.

Effect of selective versus nonselective cyclooxygenase inhibitors on gastric ulceration scores and intestinal inflammation in horses.

OBJECTIVE: To determine whether a cyclooxygenase (COX)-2 selective nonsteroidal anti-inflammatory drug (NSAID) would reduce gastric ulceration and gastrointestinal (GI) inflammation compared with a non-COX selective NSAID. STUDY DESIGN: Randomized block design. ANIMALS: Twenty-five healthy adult horses. METHODS: Horses were randomly assigned to receive placebo (n = 5), phenylbutazone (n = 10), or firocoxib (n = 10) administered daily for 10 days. Gastroscopy was performed on days 0 and 10, and both squamous and glandular ulcers were scored according to established scoring criteria. Fecal samples were collected on days 0, 10, and 20 to test for fecal myeloperoxidase (MPO) concentration by enzyme-linked immunosorbent assay. RESULTS: Both classes of NSAID induced GI injury as determined by gastric ulceration scores and fecal MPO. Glandular gastric ulceration scores and fecal MPO concentrations were higher in horses treated with phenylbutazone at day 10 (P < .001 and P = .0018, respectively). Increases in fecal MPO were significantly decreased 10 days following cessation of treatment for firocoxib but remained greater than baseline for the phenylbutazone group. CONCLUSION: Although both classes of NSAID induced gastric ulceration, the COX-2 selective NSAID firocoxib induced less severe glandular ulceration. Although there were increases in fecal MPO in both groups after 10 days of treatment, this increase was significant only in horses receiving the nonselective COX inhibitor phenylbutazone. CLINICAL SIGNIFICANCE: These findings suggest that both classes of NSAID induce GI injury in horses; however, at the dosages used in this study, the COX-2 selective NSAID firocoxib resulted in less severe injury.

Antibody to Poly-N-acetyl glucosamine provides protection against intracellular pathogens: Mechanism of action and validation in horse foals challenged with Rhodococcus equi.

Immune correlates of protection against intracellular bacterial pathogens are largely thought to be cell-mediated, although a reasonable amount of data supports a role for antibody-mediated protection. To define a role for antibody-mediated immunity against an intracellular pathogen, Rhodococcus equi, that causes granulomatous pneumonia in horse foals, we devised and tested an experimental system relying solely on antibody-mediated protection against this host-specific etiologic agent. Immunity was induced by vaccinating pregnant mares 6 and 3 weeks prior to predicted parturition with a conjugate vaccine targeting the highly conserved microbial surface polysaccharide, poly-N-acetyl glucosamine (PNAG). We ascertained antibody was transferred to foals via colostrum, the only means for foals to acquire maternal antibody. Horses lack transplacental antibody transfer. Next, a randomized, controlled, blinded challenge was conducted by inoculating at ~4 weeks of age ~10(6) cfu of R. equi via intrabronchial challenge. Eleven of 12 (91%) foals born to immune mares did not develop clinical R. equi pneumonia, whereas 6 of 7 (86%) foals born to unvaccinated controls developed pneumonia (P = 0.0017). In a confirmatory passive immunization study, infusion of PNAG-hyperimmune plasma protected 100% of 5 foals against R. equi pneumonia whereas all 4 recipients of normal horse plasma developed clinical disease (P = 0.0079). Antibodies to PNAG mediated killing of extracellular and intracellular R. equi and other intracellular pathogens. Killing of intracellular organisms depended on antibody recognition of surface expression of PNAG on infected cells, along with complement deposition and PMN-assisted lysis of infected macrophages. Peripheral blood mononuclear cells from immune and protected foals released higher levels of interferon-γ in response to PNAG compared to controls, indicating vaccination also induced an antibody-dependent cellular release of this critical immune cytokine. Overall, antibody-mediated opsonic killing and interferon-γ release in response to PNAG may protect against diseases caused by intracellular bacterial pathogens.

Effects of priming with cytokines on intracellular survival and replication of Rhodococcus equi in equine macrophages.

Rhodococcus equi is a common cause of pneumonia in foals and an opportunistic pathogen in immunosuppressed people. The ability of R. equi to survive and replicate in macrophages is the basis of its pathogenicity. Limited knowledge about the role of cytokines in host defense against R. equi comes from studies in mice and the role of cytokines in intracellular survival of R. equi in equine macrophages is unknown. The objectives of this study were to determine the effect of priming with interferon (IFN)-γ, interleukin (IL)-1ß, IL-4, IL-6, IL-10, or tumor necrosis factor (TNF)-α at various concentrations on intracellular survival of virulent R. equi in equine monocyte-derived macrophages (MDM), and to determine the effects of various combinations of the same cytokines on intracellular survival of R. equi. MDM from 10 adult horses were primed with recombinant equine cytokines at doubling concentrations ranging from 25 to 200 ng/mL prior to infection with virulent R. equi. Priming with IFN-γ, TNF-α, or IL-6 significantly decreased intracellular replication of R. equi compared to unprimed monolayers. In contrast, priming with IL-10 or IL-1ß significantly increased intracellular replication of R. equi. Pairwise combinations of the cytokines listed above did not results in synergism or antagonism. This study demonstrated that IFN-γ, TNF-α, or IL-6 improved equine MDM function against R. equi whereas IL-1ß or IL-10 were detrimental.

Ex vivo comparison of single-layer and double-layer laparoscopic closure of equine bladders with 2 types of barbed sutures.

OBJECTIVE: To compare laparoscopic single-layer versus double-layer closure of experimental, full-thickness incisions in adult equine urinary bladders using unidirectional and bidirectional barbed suture. STUDY DESIGN: Experimental, ex vivo, surgical study. SAMPLE POPULATION: Thirty adult equine cadaver urinary bladders. METHODS: Bladders were randomly divided into 5 groups (n = 6): intact controls, bladders sutured with unidirectional or bidirectional barbed suture in a single-layer closure, and bladders sutured with unidirectional or bidirectional barbed suture in a double-layer closure. A 5-cm apical incision was created in each bladder assigned to a suture group, prior to closure in a laparoscopic trainer. After suturing, bursting pressures (BPs) were determined by filling the bladders with saline to failure. Continuous variables were compared among groups using generalized linear modeling with post hoc testing between groups, and categorical variables were compared using Fisher's exact test. Significance was set at P < .05. RESULTS: No difference in BP was detected between treatment groups, all failing at pressures lower than those of intact bladders. The 95% confidence interval for BPs exceeded a physiologically relevant threshold of 30 mm Hg after single-layer or double-layer closure. Irrespective of treatment group, surgical time decreased with experience, and the rate of reduction was greater for the single-layer than the double-layer closures. CONCLUSION: In this ex vivo study, both closure techniques and both suture types appeared to be acceptable for laparoscopic closure of the urinary bladder in adult horses.

Early Blockade of Matrix Metalloproteinases in Spinal-Cord-Injured Dogs Results in a Long-Term Increase in Bladder Compliance.

Spinal cord injury (SCI) is often accompanied by reduced bladder compliance, which contributes to adverse conditions including urinary tract infections and vesicoureteral reflux. Reduced compliance is, in part, attributed to extensive remodeling of the bladder wall, including the extracellular matrix (ECM). Here, we tested the hypothesis that blockade of matrix metalloproteinases (MMPs), known for their ability to remodel the ECM, improves bladder compliance in dogs with SCI. We first evaluated dogs with naturally occurring SCIs resulting from intervertebral disc herniation (IVDH). After characterizing the natural history of urological recovery by cystometry in healthy dogs (n = 10) and dogs with SCIs (n = 20), we conducted a randomized, double-blinded, placebo-controlled clinical trial in dogs with IVDH-associated SCIs to assess the efficacy of the broad-spectrum MMP inhibitor, GM6001, given within 48 h post-injury. The primary outcomes were bladder compliance, as measured by cystometry, and an ordinal gait score (Texas Spinal Cord Injury Score; TSCIS) at day 42 post-SCI. Dogs (n = 93) were randomized to receive either dimethyl sulfoxide (DMSO) or GM6001+DMSO. There were transient, but significantly (p = 0.023) greater, adverse events (31 of 42; 74%) in the GM6001-treated group relative to vehicle controls (22 of 46; 48%). Whereas there were no differences in TSCIS between treatment groups at day 42 (p = 0.9679), bladder compliance was significantly higher in dogs treated with GM6001+DMSO compared to controls (p = 0.0272). Further studies are needed to determine whether this inhibition results from a direct interaction with the bladder wall or indirectly through neural-based mechanisms.

Duodenojejunal mesenteric rents: Survival and complications after surgical correction in 38 broodmares (2006-2014).

OBJECTIVES: To describe short-term and long-term survival of horses with duodenojejunal mesenteric rents, and to examine the association of selected preoperative, intraoperative, and postoperative factors with survival or colic after discharge, in horses with duodenojejunal mesenteric rents. STUDY DESIGN: Retrospective case series. ANIMALS: Horses undergoing surgery for correction of small intestinal lesions secondary to duodenojejunal mesenteric rents (n = 38). METHODS: Medical records (2006-2014) of horses admitted to a referral hospital in Kentucky were reviewed. Data for preoperative and intraoperative findings, postoperative complications, and short-term survival to discharge were recorded Long-term (>12 months) survival was determined by follow-up telephone query. Association of factors with survival and colic after discharge was determined using logistic regression. RESULTS: All 38 horses were Thoroughbred broodmares. Short-term survival was 76% overall and 88% among horses that recovered from general anesthesia. Long-term survival was 74% overall and 97% for mares that survived to discharge. All long-term survivors and 85% of mares that recovered from general anesthesia returned to use for breeding. The odds of survival were significantly higher for horses ≤10 years of age (OR = 6.2; 95% CI, 1.1-34.4). Failure to close the rent was associated with increased odds of colic after discharge, but had no effect on survival. CONCLUSION: Short-term and long-term survival was high relative to prior reports and mares surviving to discharge following mesenteric rent surgery had an excellent prognosis for long-term survival. Based on our data, closure of rents is recommended to prevent recurrence of colic, but may be unnecessary for survival.

Multi-Center Retrospective Evaluation of Screw and Polymethylmethacrylate Constructs for Atlantoaxial Fixation in Dogs.

OBJECTIVE: To evaluate outcome and adverse events following ventral stabilization of the atlantoaxial (AA) joint in dogs with clinical AA subluxation using screw/polymethymethacrylate (PMMA) constructs in a retrospective, multi-center cohort study. STUDY DESIGN: Historical cohort study. ANIMALS: 35 client-owned dogs. METHODS: Medical records from 3 institutions were reviewed to identify dogs with AA subluxation treated with ventral screw and PMMA constructs. Data on signalment, pre- and postoperative neurologic status, imaging performed, and adverse events were retrieved. Neurologic examination data were abstracted to generate a modified Frankel score at admission, discharge, and re-examination. Telephone interview of owners >180 days postoperative was conducted. RESULTS: Thirty-five dogs with AA subluxation treated with ventral screw/PMMA constructs were included. Most dogs were young (median age 1 year), small breed dogs with acute onset of neurologic signs (median duration 22.5 hours). Most dogs were non-ambulatory at the time of admission (median modified Frankel score 3). Adverse events were identified in 15/35 dogs including 9 dogs with major adverse events. Four dogs required a second surgery due to vertebral canal violation (n = 2) or implant failure (n = 2). Re-examination at 4-6 weeks postoperative reported 15/28 dogs with improved neurologic status and 19/28 dogs were ambulatory. Telephone follow-up was available for 23/35 dogs with 23/23 reported as ambulatory (median follow-up 390 days). CONCLUSIONS: Ventral application of screw and PMMA constructs for AA subluxation, as described here, is associated with clinical improvement in the majority of dog. Major adverse events are infrequent and the technique is considered relatively safe.