The efficacy of injecting a distillate of the pitcher plant (Sarraceniaceae) adjacent to the palmar digital nerves of horses to ameliorate lameness caused by digital pain.

This study aimed to determine the efficacy of instilling extract of the pitcher plant around the palmar digital nerves of horses to ameliorate digit pain causing lameness. Five mixed breed horses were recruited. Horses were determined to be lame because of pain in the distal portion of one or both thoracic limbs by a positive response to a basisesamoid nerve block using 2%^mepivacaine hydrochloride. Gait was evaluated pre- and post-nerve block at 30 min, 3, 7,14 and 21 days. At the 3-week evaluation, the basisesamoid nerve block was repeated using the extract, and the gait was evaluated at similar times. Lameness was evaluated objectively using a wireless, inertial, sensor-based, motion analysis system. The basisesamoid nerve block significantly ameliorated lameness at 30 min when gait was evaluated, but it had no significant effect on lameness after this time. The product containing extract of the pitcher plant had no significant effect on lameness when administered as a basisesamoid nerve block at any time. Extract of the pitcher plant administered adjacent to the medial and lateral palmar digital nerves (i.e., a basisesamoid nerve block) had no efficacy in ameliorating lameness in the distal portion of one or both thoracic limbs. Extract of the pitcher plant likely has no value for treating horses for chronic pain when administered as a regional nerve block.

Introduction to Equine Biologic and Regenerative Therapies.

Regenerative medicine is defined as the process of replacing or regenerating cells, tissues, or organs to restore or establish normal function. The use of regenerative medicine in equine practice to treat injured musculoskeletal tissues with limited capacity for intrinsic healing is growing. This article provides the practitioner with a brief and basic overview of the regenerative products currently used in equine practice.

Culture Media Supplemented With 10% Equine Serum Provided Chondroprotection in an In Vitro Co-Culture of Cartilage and Synovial Membrane.

No studies have evaluated the effect of culture in serum-free media (SF) vs. media supplemented with equine serum (ES) on co-culture of synovial membrane and cartilage tissue explants. The study objective was to evaluate the effects of equine serum supplementation on induced production of inflammatory and catabolic mediators from articular cartilage and synovial explants while in co-culture. Articular cartilage and synovial membrane explants were harvested from femoropatellar joints of five adult horses. Cartilage and synovial explants were harvested from the stifle of five horses, placed in co-culture, stimulated with IL-1ß (10 ng/ml) and maintained in culture for 3, 6 and 9 days in 10% ES or SF. At each time point, media was harvested for analysis of cellular viability (Lactate dehydrogenase) and elution of glycosaminoglycans (Dimethylene Blue Binding Assay). Tissue explants were harvested for histopathologic and gene expression analyses. No differences in cell viability were observed between SF and ES groups. SF culture produced an upregulation of TNF-α in synovial membrane and ADAMTS-4 and five in articular cartilage at 9 days of culture. ES produced an upregulation of aggrecan expression in cartilage at 9 days of culture. No differences in tissue viability were found between culture media, but SF media produced a higher glycosaminoglycan concentration in media at 3 days of culture. The addition of 10% ES produced a slight chondroprotective effect in an inflamed co-culture system. This effect should be considered when designing studies evaluating treatment of serum or plasma-based orthobiologic studies in vitro.

Horse serum or equine platelet lysate increases total vascular endothelial growth factor A concentrations and correlates with vascular growth in an equine facial arterial ring assay.

OBJECTIVE: To evaluate ex vivo angiogenesis of equine arterial rings in response to various growth media. ANIMALS: Facial arteries were dissected from 11 horses post-euthanasia. Equine platelet lysate (ePL) was harvested from 6 horses. PROCEDURES: Arteries were exposed to endothelial growth media (EGM) + horse serum (HS) for first sprout (FS), vascular regression (VR), and (basement membrane matrix [Matrigel]) lysis (ML) evaluation. Additional rings supplemented with (1) EGM, (2) EGM + EDTA, (3) endothelial basal media (EBM), (4) EBM + HS, or (5) EBM + human VEGF were compared for vascular network area (VNA) and maximum network growth (MNG). Additional rings exposed to EGM + ePL at 10-(10xePL), 5-(5xePL), or 2-fold (2xePL) increases from baseline platelet concentration, EGM + HS, EGM + platelet-poor plasma (PPP), EBM + PPP and EBM were analyzed for branch number, density, VNA, and VEGF-A concentration from days 0-3. RESULTS: Arteries demonstrated sprouting in Matrigel supplemented with EBM alone. EGM + HS exposure resulted in no differences in FS (P = .3934), VR (P = .0607), or ML (P = .2364) between horses. VNA in EGM + HS was greater than EBM (P = .0015). MNG was greater in EGM + HS, EBM + HS, and EBM + hVEGF compared with EBM (P = .0001). ePL treatment did not have an overall significant angiogenic effect compared with supplementation with HS, PPP, or EBM alone; however, VEGF-A concentrations were higher for EGM + 10xePL, EGM + 5xePL, and EGM-HS compared with EBM and positively correlated with VNA (P = .0243). CLINICAL RELEVANCE: Equine arterial rings serve as an ex vivo model for angiogenesis but have a high degree of variability. HS, PPP, or ePL support vascular growth, and HS and ePL may stimulate the secretion and be sources of VEGF-A.

Retrospective analysis of postoperative complications following surgical treatment of ileal impaction in horses managed with manual decompression compared to jejunal enterotomy.

Objective: The objective of this study was to compare the occurrence of post-operative complications and survival to discharge in horses with ileal impactions resolved by manual decompression compared with jejunal enterotomy. Animals: A total of 121 client-owned horses undergoing surgical correction of an ileal impaction at three teaching hospitals. Materials and methods: Data from the medical records of horses undergoing surgical correction of an ileal impaction was retrospectively collected. Post-operative complications, survival to discharge, or post-operative reflux present were evaluated as dependent variables and pre-operative PCV, surgery duration, pre-operative reflux, and type of surgery were evaluated as independent variables. Type of surgery was divided into manual decompression (n = 88) and jejunal enterotomy (n = 33). Results: There were no significant differences in development of minor complications, development of major complications, presence of post-operative reflux, amount of post-operative reflux, and survival to discharge between horses that were treated with manual decompression and those treated with distal jejunal enterotomy. Pre-operative PCV and surgery duration were significant predictors of survival to discharge. Conclusions and clinical relevance: This study showed that there are no significant differences in post-operative complications and survival to discharge in horses undergoing distal jejunal enterotomy versus manual decompression for correction of ileal impaction. Pre-operative PCV and duration of surgery were found to be the only predictive factors of survival to discharge. Based on these findings, distal jejunal enterotomy should be considered earlier in horses with moderate to severe ileal impactions identified at surgery.

Concurrent versus delayed exposure to corticosteroids in equine articular tissues cultured with local anesthetic.

OBJECTIVE: To determine the effect of concurrent versus delayed treatment with corticosteroid on equine articular tissues also treated with local anesthetic in vitro in the presence of inflammatory mediators. STUDY DESIGN: Controlled laboratory study. ANIMALS: Five geldings, one mare (aged 3-18 years). METHODS: From each horse, 24 synovial and 12 osteochondral explants were cultured in a 12-well plate (2 wells/group, 2 synovial and 1 osteochondral explant/well, total 216 explants in the study). Explants were stimulated in culture medium with 10 µg/ml recombinant equine interleukin-1ß and 10 µg/ml tumor necrosis factor-α for 48 hours, then randomly assigned to six treatments: unstimulated control, stimulated control, triamcinolone acetonide (TA, 10-6  M), mepivacaine hydrochloride (MH, 4.4 mg/ml), MH + TA (concurrent) and MH + TA (delayed). The delayed group was treated with MH and, 6 days later, treated with TA. Every 3 days for 9 days total, medium levels of lactate dehydrogenase (LDH), prostaglandin E2 (PGE2 ), matrix metalloproteinase 13 (MMP-13) and glycosaminoglycan (GAG) were quantified via ELISA. Data were analyzed with mixed-effects models with Tukey's multiple comparisons. RESULTS: Stimulation increased medium PGE2 and MMP-13 and had no effect on LDH or GAG. Treatment with MH increased LDH and decreased PGE2 and MMP-13. Treatment with TA decreased PGE2 and MMP-13. CONCLUSION: There were no differences in cytotoxicity, inflammation or matrix degradation for delayed or concurrent MH and TA treatment groups up to 9 days in culture. CLINICAL SIGNIFICANCE: The lack of an effect of concurrent versus delayed treatment might indicate that concurrent therapy is acceptable.

Effect of single and double hemitenotomy on equine deep digital flexor tendon length and strength in experimental load challenges.

OBJECTIVE: To evaluate a double hemitenotomy (DHT) technique as an alternative to complete deep digital flexor (DDFT) tenotomy. STUDY DESIGN: Experimental ex vivo study. SAMPLE POPULATION: Isolated DDFTs (n = 30) and cadaveric forelimbs (n = 16). METHODS: In part 1, 15 isolated DDFT pairs were used. Two hemitenotomies were created in 1 DDFT while the other served as reference. Monotonic tensile load was applied. Tendon lengthening, load reduction, and load at failure were recorded. In part 2, 16 cadaveric forelimb pairs were subjected to DHT followed by complete tenotomy (CT) under monotonic compressive load. Differences between DHT and controls were assessed with Wilcoxon signed rank tests or Friedman tests. RESULTS: In isolated tendons and cadaveric forelimbs, DHT resulted in DDFT lengthening (median, +1.9 mm and + 3.05 mm) and load reduction (median, -16.7 and -11.2 kg). Less lengthening was achieved with DHT compared to CT (P = .008). Load reduction did not occur between DHT and CT was observed during compressive testing (P = 1). Load reduction following the first hemitenotomy incision was smaller when compared to the second (P = .022). Isolated DHT tendons failed at a tensile load of 195 kg, while no intact tendons failed (P = .0001). CONCLUSION: Double hemitenotomy was comparable to CT in load reduction. It reduced tensile strength, but load at failure was similar or exceeded the estimated DDFT load at stance. CLINICAL SIGNIFICANCE: Hemitenotomy may be a useful alternative for surgical management of horses with laminitis, but in vivo studies are needed to confirm these findings.

The Effect of Inhaled Albuterol on PaO2 in Anesthetized Horses Receiving a FiO2 of 0.5 or >0.95.

Impairment of oxygen uptake can occur during general anesthesia in horses resulting in hypoxemia. Multiple treatments have been investigated for correction of hypoxemia with varying levels of success. In clinical trials, albuterol, a short-acting ß2 adrenergic agonist, improved arterial oxygen partial pressure (PaO2) in anesthetized horses unresponsive to adjustments in mechanical ventilation and administration of positive inotropic drugs. However, controlled studies comparing the magnitude of change and duration of effect of albuterol on PaO2 in healthy, nonhypoxemic anesthetized horses are lacking. In a prospective study, 14 horses were anesthetized and received a FiO2 of 0.5 (n = 7) or > 0.95 (n = 7). Horses were maintained on isoflurane and mechanically ventilated. After 15 minutes, baseline PaO2 was determined. Within each FiO2 group, five horses were administered inhaled albuterol (2 µg/kg) and two horses received no treatment. At 10, 20, 30, and 40 minutes after baseline, PaO2 was measured. Data for horses that received albuterol were analyzed with repeated measures analysis of variance with significance at P < .05. Horses that received albuterol had an increase in PaO2 for at least 40 minutes after baseline. Albuterol administered via inhalation, was associated with an increased PaO2 of at least 40 minutes compared to baseline in healthy, nonhypoxemic horses undergoing anesthesia at similar depth, using a FiO2 of 0.5 and > 0.95. Side effects were mild and consisted of increased heart rate and sweating. Albuterol administered at 2 µg/kg via inhalation may be useful for increasing PaO2 in anesthetized horses.

Comparison of 2% mepivacaine and a solution of 2% lidocaine/epinephrine administered for median and ulnar nerve blocks in horses with naturally occurring forelimb lameness.

OBJECTIVE: To compare a 2% lidocaine solution containing 5 µg/ml (1:200 000) epinephrine with 2% mepivacaine for reducing lameness in horses after use in proximal nerve blocks. STUDY DESIGN: Experimental randomized crossover. ANIMALS: Six adult horses with naturally occurring forelimb lameness. METHODS: Horses were evaluated using an inertial gait sensor system. Lameness was measured as a vector sum (VS). Following baseline lameness examination, median and ulnar nerve blocks were performed with lidocaine/epinephrine (0.5 mg epinephrine added to 50 ml of 2% lidocaine immediately prior to administration) or an equal volume of 2% mepivacaine. Horses were trotted at 5 min and then at 30 min intervals for 150 min. After 24 h, nerve blocks were repeated using the other local anesthetic. Data were evaluated using linear models. RESULTS: The reduction in the VS did not differ after nerve blocks with lidocaine/epinephrine or mepivacaine (P = .791). Mean time to VS <8.5 mm (n = 5) was 5 and 9.6 min for lidocaine/epinephrine and mepivacaine, respectively. For one horse, VS was not reduced to <8.5 mm with either treatment (this horse had the highest VS before treatments were administered). The decrease in VS to <8.5 mm lasted for 150 min in both treatment groups. CONCLUSION: The outcomes of the median and ulnar nerve blocks performed with 2% lidocaine with epinephrine did not differ from blocks performed with 2% mepivacaine. CLINICAL RELEVANCE: Two percent lidocaine with epinephrine may serve as an adequate replacement for proximal nerve blocks when mepivacaine is unavailable.

Hybrid natural orifice transluminal endoscopy surgery (NOTES) to perform bilateral ovariectomy in mares.

OBJECTIVES: To combine laparoscopic techniques with natural orifice transluminal endoscopic surgery (hybrid NOTES) to minimize number and enlargement of paralumbar laparoscopic portals for bilateral ovariectomy in standing, sedated mares. STUDY DESIGN: Case series. ANIMALS: Six horses. MATERIALS AND METHODS: Six mares with palpably normal ovaries were restrained in stocks, sedated, and had caudal epidural anesthesia performed. A 7.5 MHz ultrasound probe was used transvaginally to select placement of vaginotomy. An attempt was made to remove both ovaries with 70 cm esophageal forceps through the vaginotomy, while visualized and transected via ipsilateral paralumbar fossa laparoscopic portals. Surgical time, intraoperative, and postoperative complications were recorded. Vaginoscopy was performed at days 0, 3, 7, and 14 postoperatively. After 14 days, mares were euthanized and necropsied. RESULTS: Hybrid NOTES allowed successful bilateral ovariectomy in all six mares, with a mean surgical time of 70 ± 25 min. In two mares, one ovary was dislodged from the forceps during vaginotomy extraction. Abdominal retrieval of the ovary was successful with reapplication of forceps or a surgeon's hand via vaginotomy. At necropsy, five mares had no adhesions within the abdominal cavity or at the vaginotomy site. One mare in which hand retrieval of the ovary was necessary, developed an adhesion between the bladder and the vaginotomy. CONCLUSIONS: This technique appears to offer a safe alternative for bilateral ovariectomy with minimal postoperative complications. CLINICAL SIGNIFICANCE: Decreased number and size of paralumbar laparoscopic incisions could decrease complications associated with exteriorization of ovaries through the flank.

Partial parotid sialoadenectomy in a horse with parotid ductal carcinoma: Surgical description and case report.

OBJECTIVES: To describe the surgical findings, histopathological features, and long-term outcome for a horse with parotid salivary carcinoma. STUDY DESIGN: Case report ANIMALS: Twelve year old American Quarter Horse gelding. METHODS: The gelding was presented for a 10 × 10 cm swelling below the base of the right ear. Ultrasonographic examination revealed a mass involving the right parotid salivary gland. Incisional biopsy was consistent with parotid carcinoma. The tumor was marginally excised. The lateral wall of the guttural pouch was excised with the mass and was reconstructed with a porcine small intestinal submucosal (SIS) sheet. Cisplatin beads were implanted in the wound bed prior to closure. Firocoxib (0.1 mg/kg orally, daily, every 24 h) treatment was initiated. RESULTS: Postoperative complications included right-sided facial nerve paralysis, difficulty with deglutition of fibrous feeds, and surgical site dehiscence. Wound healing was achieved by second intention. Partial improvement in nerve function was observed within the first 6 months. At 12 months postparotidectomy, no sign of tumor reoccurrence or metastatic disease was present, and the gelding returned to work. CONCLUSION: Partial parotid sialoadenectomy was performed with a favorable long-term outcome. Regional anatomic knowledge is crucial.

Effect of recombinant equine interleukin-1ß on function of equine endothelial colony-forming cells in vitro.

OBJECTIVE: To investigate the effects of recombinant equine IL-1ß on function of equine endothelial colony-forming cells (ECFCs) in vitro. SAMPLE: ECFCs derived from peripheral blood samples of 3 healthy adult geldings. PROCEDURES: Function testing was performed to assess in vitro wound healing, tubule formation, cell adhesion, and uptake of 1,1'-dioctadecyl-3,3,3',3' tetramethylindocarbocyanine perchlorate-labeled acetylated low-density lipoprotein (DiI-Ac-LDL) by cultured ECFCs. Cell proliferation was determined by 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide assay. Effects on function test results of different concentrations and exposure times of recombinant equine IL-1ß were assessed. RESULTS: Challenge of cultured ECFCs with IL-1ß for 48 hours inhibited tubule formation. Continuous challenge (54 hours) with IL-1ß in the wound healing assay reduced gap closure. The IL-1ß exposure did not significantly affect ECFC adhesion, DiI-Ac-LDL uptake, or ECFC proliferation. CONCLUSIONS AND CLINICAL RELEVANCE: These results suggested a role for IL-1ß in the inhibition of ECFC function in vitro. Functional changes in ECFCs following challenge with IL-1ß did not appear to be due to changes in cell proliferative capacity. These findings have implications for designing microenvironments for and optimizing therapeutic effects of ECFCs used to treat ischemic diseases in horses.

Clinical features, treatment, and outcome of aural hematomas in horses: 7 cases (2008-2019).

OBJECTIVE: To characterize the clinical features, treatment, and outcome of aural hematomas in horses. ANIMALS: 7 horses with 1 or 2 aural hematomas (8 ears in total) treated at a veterinary teaching hospital in 2008 through 2019. PROCEDURES: Data retrieved from medical records included signalment, pertinent historical information, clinical signs, diagnostic procedures (including dermatologic assessment), and treatments. Case outcome was determined from documentation in the medical record or via telephone communication with owners or referring veterinarians. RESULTS: 3 horses were presented after recurrence of aural hematoma following treatment by the referring veterinarian. Four horses had a history of allergic skin disease prior to aural hematoma development. Most (6/7) horses were unilaterally affected. Diagnostic assessments included otoscopic evaluation (3 horses), ultrasonography (3 horses), cytologic examination of ear canal swab samples (3 horses), and histologic examination of a pinnal biopsy specimen (1 horse). Of the 8 pinnae, 2 were treated by nonsurgical needle drainage (1 with concurrent corticosteroid injection) and the remaining 6 underwent surgical incision and placement of compressive sutures. Follow-up information was available for 6 horses, and all affected pinnae were fibrotic with 4 horses having permanent drooping of the pinna. One horse developed a hematoma in the contralateral pinna 1 year after hospital discharge. CONCLUSIONS AND CLINICAL RELEVANCE: Equine aural hematoma is a rare condition. The main principle of treatment is drainage, and treatment options commonly used in small animal practice can be successfully applied in horses. Permanent changes in the cosmetic appearance of the pinna are likely to develop owing to secondary fibrosis.

Minimally invasive tenotomy of the tibial insertion of the semitendinosus muscle: An ex vivo study in horses.

OBJECTIVE: To describe a minimally invasive technique for semitendinosus tenotomy with ultrasonographic guidance and to evaluate procedural complications. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Cadaveric equine hind limbs (n = 16). METHODS: A stab incision was performed distocaudal to the tibial insertion of the semitendinosus muscle with ultrasonographic assistance. After transection of the tendon with an arthroscopic retrograde knife, the tendon edges palpably retracted, and complete transection was confirmed by ultrasound. Limbs were dissected to confirm the degree of tendon transection and to identify iatrogenic trauma to surrounding soft tissues. RESULTS: Tenotomy was complete in all limbs, resulting in a palpable gap forming between tendon edges. Superficial iatrogenic laceration to the underlying gracilis muscle (n = 2) or gracilis fascia (n = 1) was apparent in 3 of 16 limbs. CONCLUSION: Ultrasound-assisted tenotomy of the tibial insertion of the semitendinosus muscle was reliably performed in a minimally invasive fashion with minor iatrogenic damage. CLINICAL SIGNIFICANCE: Minimally invasive tenotomy of the semitendinosus muscle can be performed with ultrasonographic assistance and should be considered as an alternative technique for surgical management of fibrotic semitendinosus myopathy.

Ex vivo comparison of the bursting strength of an equine ventral midline celiotomy covered by two standard abdominal bandages.

OBJECTIVE: To determine the compressive effect of abdominal bandages after ventral midline celiotomy closure in horses. STUDY DESIGN: Ex vivo, experimental study. ANIMALS: Equine cadavers (n = 18), six per group. METHODS: A 20-cm ventral midline celiotomy was created in each of 18 equine cadavers. A 200-L inflatable bladder was placed in the abdomen, and the linea alba was apposed. Horses were randomly assigned to no bandage (C), elastic (E), or Velcro inelastic (I) bandage groups for testing. Circumferential bandages were placed with a subbandage pressure monitoring system over the incision. The bladder was insufflated until construct failure, which was determined by a decrease in pressure reading. Bursting pressure, location of body wall or bandage failure, and subbandage pressures were recorded. RESULTS: Maximum bursting pressure was different between groups E and C (P = .004), with no difference between groups E and I (P = .146) or I and C (P = .085). Group I achieved higher subbandage pressure compared with group E (P = .036). Abdominal compliance was not different between groups (P = .099). Location of failure differed between groups (P = .011), with failure at the diaphragm more common in group I (6/6, 100%) compared with groups E (3/6 [50%]) and C (1/6 [16.7%]). CONCLUSION: Elastic abdominal bandages had higher abdominal bursting pressures compared with unbandaged incisions.

Meningitis After Tooth Extraction and Sinus Lavage in a Horse.

A five-year-old Thoroughbred mare was evaluated because of chronic, malodorous, unilateral nasal discharge, and suspected maxillary cheek tooth root abscess. Skull radiographs revealed bilateral sinusitis suspected secondary to tooth root abscessation of 109 and 210. Following oral extraction of 109, bilateral conchofrontal sinus trephination and lavage; fever, tachycardia, and cervical stiffness developed. A lumbosacral cerebrospinal fluid tap was performed, and a presumptive diagnosis of bacterial meningitis was made. Targeted therapy consisted of antibiotic treatment with penicillin, enrofloxacin, and metronidazole, as well as antiinflammatory treatment with flunixin meglumine, dexamethasone, and dimethyl sulfoxide. Following the resolution of fever, tachycardia, and cervical stiffness, the second abscessed tooth, 210, was extracted. The mare was discharged receiving enrofloxacin. Twelve months later, the mare continued to do well with no residual signs of meningitis. Bacterial meningitis should be regarded as a life-threatening, although rare, the complication of dental or sinus surgery in horses. Early diagnosis and therapy may result in a successful outcome.

A Survey of Clinical Usage of Non-steroidal Intra-Articular Therapeutics by Equine Practitioners.

There are several non-steroidal intra-articular therapeutics (NSIATs) available for use by equine practitioners for the treatment of performance-limiting joint-related pathology. Information is limited on perceived clinical efficacy, recommended treatment protocols, and associated complications. Our objective with this cross-sectional survey was to investigate the current clinical usage of NSIATs by equine practitioners. An electronic cross-sectional convenience survey inquiring about the use of steroidal and NSIATS (platelet-rich plasma, autologous conditioned serum, autologous protein solution, cellular therapies, and polyacrylamide hydrogel) was distributed internationally to equine practitioners. A total of 353 surveys were completed. NSIATs were used by 87.5% of the participants. Corticosteroids and hyaluronic acid remain the intra-articular therapeutic of choice among practitioners, followed by autologous conditioned serum, platelet-rich plasma and autologous conditioned protein. Polyacrylamide hydrogel was the least used. Practitioners were more likely to use NSIATs if their caseload was > 50% equine (P < 0.001), they treated more than 10 horses intra-articularly per month (P < 0.001), and horses treated were considered English sport horses (P = 0.02). Years in practice and practice location did not influence the use of NSIATs. One of the most common reasons why NSIATs were chosen was to treat acute articular pathologies. As survey limitations, answers to questions regarding clinical response and complication rates were based on subjective estimation and practitioners recall, not clinical records. In conclusion, corticosteroids remain the most widely used intra-articular therapeutic. Among the NSIATs, blood-based products are more commonly used by practitioners, followed by cellular and synthetic products. Equine practitioners frequently use NSIATs, choosing to treat acute joint pathology more than previously reported.

Tensile strength and early healing of self-locking and surgeon's knots.

OBJECTIVE: To compare the biomechanical properties and healing of ventral midline celiotomies (VMC) closed with a self-locking knot combination and forwarder start and Aberdeen end (F-A) vs a traditional knot combination and surgeon's start and end (S-S). STUDY DESIGN: In vivo, experimental. ANIMALS: Twenty-one horses. METHODS: Fourteen horses underwent VMC, which was closed with either an F-A (n = 7) or an S-S (n = 7) knot combination. Incisions were subjectively graded by masked evaluators for dehiscence, edema, and drainage. Biomechanical testing was performed on three abdominal segments, and histology was performed on one segment from each animal after humane euthanasia 10 days post-VMC. The abdominal wall of control horses (n = 7, no celiotomy) was collected for biomechanical testing. RESULTS: Forwarder start and Aberdeen end and S-S horses had less tensile strength compared with control horses (P ≤ .001). No differences were detected between treatment groups for any variable evaluated, including tensile strength (P = .975), location of failure (P = .240), and histologic healing at the knot (P = .600). CONCLUSION: Closure of VMC with self-locking knots resulted in biomechanical and healing features similar to those with a traditional closure technique, with neither restoring the tensile strength of the linea alba. CLINICAL SIGNIFICANCE: Results of this study provide evidence to support a clinical trial to evaluate long-term performance of the F-A self-locking knot closure in horses.

Actinomyces as a Cause of Osteomyelitis of the Nasofrontal Suture in a Gelding.

A 7-year-old American Quarter Horse gelding was referred to the JT Vaughan Large Animal Teaching Hospital at Auburn University, College of Veterinary Medicine, for an investigation of a recurrent swelling of the nasofrontal region. Computed tomography examination of the skull was most consistent with a sequestrum of the left nasofrontal suture with associated focal osteomyelitis and left conchofrontal sinusitis. Surgery to remove the sequestrum, debride the devitalized bone, and flush the left conchofrontal sinus was performed. A microbial culture was obtained at the time of surgery, which yielded a mixed heavy growth of an Actinomyces species. Quantitative PCR indicated a species with 93% resemblance to Actinomyces funkei. A treatment course of two weeks of oral chloramphenicol was prescribed. At three-month follow-up, the owner reported resolution of the swelling.

Effects of Autologous Conditioned Serum, Autologous Protein Solution, and Triamcinolone on Inflammatory and Catabolic Gene Expression in Equine Cartilage and Synovial Explants Treated With IL-1ß in Co-culture.

Autologous conditioned serum (ACS) and autologous protein solution (APS) are newer therapeutic options for osteoarthritis (OA). Co-culture of cartilage and synovium stimulated with IL-1ß produces a similar physiologic response to tissues from naturally-ocurring OA. The study objective was to investigate the effects of ACS, APS, and triamcinolone (TA) on inflammatory and catabolic gene expression of inflamed joint tissues in co-culture. Blood was collected and processed for ACS and APS from six horses. Cartilage and synovial explants were harvested from the stifle, placed in co-culture, and treated as: (1) unstimulated control (2) stimulated control (3) ACS at 25% v/v (4) ACS at 50% v/v (5) APS at 25% v/v (6) APS at 50% v/v, (7) TA (10-6 M). Treatment groups 2-7 were stimulated with IL-1ß (10 ng/ml). Cultures were maintained for 96 hours, and then both media and explants were harvested for measurement of gene expression and protein. IL-1ß stimulation significantly increased IL-1ß (p = 0.029), IL-8 (p = 0.011) and MMP-3 (p = 0.043) expression in synovium and IL-1ß (p = 0.003) and TNF-α (p = 0.001) expression in cartilage. Treatment with 50% ACS and APS v/v downregulated IL-1ß expression in cartilage more than TA treatment (p = 0.001 and p = 0.0004) and APS downregulated MMP-1 expression in synovial membrane (p = 0.025). Treatment with ACS and APS caused a trend in upregulation of IL-10 expression in synovium and type II collagen and aggrecan expression in cartilage. PGE2 media concentrations were significantly reduced following treatment with APS (13.7-fold decrease, p = 0.0001) and ACS (4.13-fold decrease, p = 0.024); while TA did not reduce PGE2 significantly (2.3-fold decreased p = 0.406). As disease-modifying therapies, ACS and APS modified the cellular response from synovial membrane and articular cartilage. ACS and APS may offer an improved strategy to improve clinical signs of horses with naturally occurring OA, compared to TA treatment.