Flowmetry and spectrophotometry can detect reduced intestinal microperfusion in nonsurvivors during equine colic surgery for large intestinal strangulation.

OBJECTIVE: To evaluate the use of laser Doppler flowmetry and spectrophotometry (LDFS) for large intestinal viability assessment in horses with naturally occurring large intestinal strangulations. METHODS: By use of LDFS, intestinal microperfusion was quantified as tissue oxygen saturation (tSo2), hemoglobin (tHB), and blood flow (tBF) in cases with large colon volvulus and small colon strangulations undergoing colic surgery (n = 17). Intestinal biopsies were taken from the pelvic flexure in all large colon cases and in small colon cases that underwent intraoperative euthanasia. Measurements were compared between survivors and nonsurvivors, and the correlation between LDFS and (immuno)histology was tested (P < .05). RESULTS: The tSo2 and tBF were clearly lower and tHB was higher than previously reported in healthy horses. Following correction of the lesion, pelvic flexure tBF was significantly lower than that of the left ventral colon. Prior to correction of the lesion, microperfusion did not differ between survivors and nonsurvivors, but following release of the strangulation the survivors had a significantly higher tSo2 and tBF compared to the nonsurvivors. There was a negative correlation between tBF and interstitium-to-crypt ratio and a positive correlation between tHB and the histological hemorrhage score. There were no significant correlations between LDFS measurements and inflammatory cell counts or hypoxia-inducible factor-1α immunoreactivity. CONCLUSIONS: Large intestinal microperfusion was decreased in nonsurvivors compared to survivors and was correlated with histological injury, suggesting that LDFS has the potential to predict tissue injury and postoperative survival. CLINICAL RELEVANCE: The use of LDFS as an ancillary diagnostic aid may improve intraoperative viability assessment during colic surgery.

Flowmetry and spectrophotometry for the assessment of intestinal viability in horses with naturally occurring strangulating small intestinal lesions.

BACKGROUND: Ancillary diagnostic methods to enhance the accuracy of viability assessment have not been established for use in clinical practice. OBJECTIVES: To assess intestinal microperfusion measured by Laser Doppler Flowmetry and Spectrophotometry (LDFS) in naturally occurring small intestinal strangulations of different origins and to compare this between viable and non-viable segments. STUDY DESIGN: Prospective clinical trial. METHODS: Forty horses undergoing colic surgery for naturally occurring small intestinal strangulations were included. Tissue oxygen saturation (tSO2), haemoglobin (tHB) and blood flow (tBF) were determined by LDFS before and after release of the strangulation. Intestinal biopsies were taken in cases that underwent intestinal resection or intraoperative euthanasia and assessed using a semi-quantitative mucosal injury score (MIS). The LDFS measurements were compared between the different categories of strangulation causes and histopathological injury using parametric and non-parametric tests (p < 0.05). RESULTS: Strangulations by pedunculated lipomas had lower tBF (13.9 ± 18 arbitrary units [AU]) than epiploic foramen entrapments (65.2 ± 61 AU; CI -1.697 to -0.2498; p = 0.005). Segments with MIS > 5 showed lower tBF during strangulation than segments with MIS < 4 (mean difference 61.1 AU; CI -1.119 to -0.07361; p = 0.03). This did not differ significantly following release of strangulation. Furthermore, there was a positive correlation between the inflammatory cell count and tBF during strangulation (r 0.34; CI 0.01 to 0.60; p = 0.04). The tSO2 and tHB did not differ between the different categories of lesions or injury. MAIN LIMITATIONS: No biopsies could be taken from the intestinal segments that did not undergo resection. The duration of strangulation could not reliably be ascertained. CONCLUSIONS: Blood flow measurements in naturally occurring strangulating lesions show a varying degree of ischaemia in different causes of strangulation. Intestinal blood flow measurements prior to release of the strangulation could potentially contribute to the identification of mucosal injury, yet a high individual variability and other contributing factors need to be considered.

Measuring tissue oxygen saturation in the orad intestinal segment during equine colic surgery may aid in predicting the occurrence of postoperative ileus.

OBJECTIVE: To assess the histological injury and intestinal microperfusion measured by laser Doppler flowmetry and spectrophotometry (LDFS) of the small intestine orad to a strangulation during colic surgery. ANIMALS: Horses with naturally occurring small intestinal strangulations undergoing colic surgery were included. METHODS: In this prospective clinical trial, intestinal tissue oxygen saturation (tSO2) and tissue blood flow (tBF) were measured by LDFS orad to the strangulation following release of the strangulation (n = 18). The number of horses with postoperative reflux (POR) and the cases that survived until discharge were compared between groups using Fisher's exact test (P < .05). Intestinal biopsies were taken in cases that underwent intestinal resection or intraoperative euthanasia (n = 28). Measurements were compared between injured and noninjured segments with a Mann-Whitney U or t test. RESULTS: The tSO2 and tBF of the orad intestine were lower than previously reported in healthy horses. Horses with low tSO2 of < 35% were significantly more likely to suffer from POR (6/6 cases) compared to cases with tSO2 > 69% (1/6). The number of horses that survived were not statistically different between these groups (2/6 and 6/6). All horses with mucosal injury developed POR (6/6), which was significantly more likely compared to horses without mucosal injury (3/13). No significant difference in tSO2 or tBF could be found between the segments with and without histological injury. CLINICAL RELEVANCE: The results suggest that measuring tSO2 in the orad segment during colic surgery may aid in predicting postoperative issues.

Treatment of Naturally Occurring Tendon Disease with Allogeneic Multipotent Mesenchymal Stromal Cells: A Randomized, Controlled, Triple-Blinded Pilot Study in Horses.

The treatment of tendinopathies with multipotent mesenchymal stromal cells (MSCs) is a promising option in equine and human medicine. However, conclusive clinical evidence is lacking. The purpose of this study was to gain insight into clinical treatment efficacy and to identify suitable outcome measures for larger clinical studies. Fifteen horses with early naturally occurring tendon disease were assigned to intralesional treatment with allogeneic adipose-derived MSCs suspended in serum or with serum alone through block randomization (dosage adapted to lesion size). Clinicians and horse owners remained blinded to the treatment during 12 months (seven horses per group) and 18 months (seven MSC-group and five control-group horses) of follow-up including clinical examinations and diagnostic imaging. Clinical inflammation, lameness, and ultrasonography scores improved more over time in the MSC group. The lameness score difference significantly improved in the MSC group compared with the control group after 6 months. In the MSC group, five out of the seven horses were free of re-injuries and back to training until 12 and 18 months. In the control group, three out of the seven horses were free of re-injuries until 12 months. These results suggest that MSCs are effective for the treatment of early-phase tendon disease and provide a basis for a larger controlled study.

Maternal allogeneic cancellous bone graft for the treatment of osteitis along the physeal scar of the proximal metatarsus in a foal.

OBJECTIVE: To describe the treatment and outcome of a foal with a fresh allogenic cancellous bone graft after surgical debridement of a traumatic septic osteitis. ANIMAL: A neonatal Quarter Horse foal. STUDY DESIGN: Case report. METHODS: The foal sustained a traumatic laceration exposing the proximal third metatarsal bone. One week after surgical debridement and closure, radiographic signs of septic osteitis were noted along the physeal scar. The lesion was debrided, and antimicrobial therapy was implemented. The infection resolved but left a large defect in the metaphysis and epiphysis. Grafting was indicated to avoid pathologic fractures of the plantar and proximal cortices. Due to a discrepancy between defect size and the bone stock of the foal, an allogeneic cancellous bone graft was harvested from the dam's tuber coxae and used to fill the foal's defect. RESULTS: No adverse reactions to the graft were noted. After 1 month, the wound had healed. Radiographic examination was consistent with graft incorporation in the bone structure. The foal was sound at a walk and trot when examined at 6, 12, and 21 months. The bone's contour was even and its structure homogeneously radio dense. The surgical site of the mare healed without complications. CONCLUSION: Fresh allogenic cancellous bone grafting resulted in the healing of a large traumatic-septic bone defect in a foal, with an excellent functional and cosmetic outcome. For future use, compatibility testing should be considered prior to allogeneic bone grafting.

Repeated intra-articular administration of equine allogeneic peripheral blood-derived mesenchymal stem cells does not induce a cellular and humoral immune response in horses.

OBJECTIVE: The use of mesenchymal stem cells (MSCs) for the treatment of equine joint disease is widely investigated because of their regenerative and immunomodulatory potential. Allogeneic MSCs provide a promising alternative to autologous MSCs, since the former are immediately available and enable a thorough donor screening. However, questions have been raised concerning the immunogenic potential of allogeneic MSCs, especially after repeated administration. METHODS: Current retrospective study assessed the cellular and humoral immunogenicity of ten jumping and dressage horses with naturally occurring degenerative joint disease which were treated 3 times intra-articularly with a 1 mL stem cell suspension containing 1.4-2.5 million chondrogenic induced equine allogeneic peripheral blood-derived MSCs (ciMSCs) combined with 1 mL equine allogeneic plasma. Stem cells from 2 donor horses were used. Horses were clinically evaluated for joint effusion, presence of pain to palpation and skin surface temperature at the local injection site, joint range of motion, occurrence of adverse events and the presence of ectopic tissue. The cellular immune response was analyzed using a modified mixed lymphocyte reaction and the humoral immune response was investigated using a flow cytometric crossmatch assay by which the presence of alloantibodies against the ciMSCs was evaluated. Presence of anti-bovine serum albumin antibodies was detected via ELISA. RESULTS: Clinical evaluation of the horses revealed no serious adverse effects or suspected adverse drug reactions and no ectopic tissue formation at the local injection site or in other areas of the body. Generally, repeated administration led to a decrease of horses with joint effusion of the affected joint. Pain to palpation, skin surface temperature and joint range of motion did not increase or even decreased after treatment administration. Allogeneic ciMSCs did not induce a cellular immune response and no alloantibodies were detected in the recipients' serum, regardless the presence of BSA antibodies in 70 % of the horses. CONCLUSION: Repeated intra-articular injections with allogeneic equine ciMSCs did not elicit clinically relevant adverse events. Furthermore, current study indicates the absence of a cellular or a humoral immune response following repeated intra-articular injections.

Laparoscopic resection of an exostosis of the os pubis in a horse.

OBJECTIVE: To report the diagnostic findings and laparoscopic removal of an exostosis of the os pubis in a horse. STUDY DESIGN: Case report. ANIMAL: One 12-year-old Black Forest draught gelding. METHODS: History included recurrent colic before and during urination and poor performance. Findings at rectal examination included a pointed osseous prominence adjacent to the symphysis of the pecten ossis pubis. Cystoscopy revealed that this prominence caused a protrusion of the bladder wall into the lumen. Standing laparoscopy and laparoscopy under general anesthesia were performed. RESULTS: After a failed attempt at standing laparoscopy, the horse was anesthetized, and the exostosis of the os pubis was removed laparoscopically without complications. No recurrence of clinical signs associated with the exostosis was detected 12 months postoperatively. CONCLUSION: Minimally invasive surgical resection of an exostosis of the os pubis was achieved under general anesthesia with appropriately designed instruments. This treatment alleviated symptoms associated with the exostosis, including potential injury of the urinary bladder wall.

Investigation of stemness and multipotency of equine adipose-derived mesenchymal stem cells (ASCs) from different fat sources in comparison with lipoma.

BACKGROUND: Adipose tissue-derived mesenchymal stem cells (ASCs) offer a promising cell source for therapeutic applications in musculoskeletal disorders. The appropriate selection of ASCs from various fat depots for cell-based therapy is challenging. The present study aims to compare stemness and multipotency of ASCs derived from retroperitoneal (RP), subcutaneous (SC), and lipoma (LP) fat to assess their usefulness for clinical application. METHODS: Equine ASCs from the three fat tissue sources were isolated and characterized. The cell viability, proliferation, and self-renewal were evaluated using MTT, sulforhodamine B, and colony forming unit (CFU) assays. Stem cell relative marker CD44, CD90, and CD105 and tumor marker CA9 and osteopontin (OPN) expression were quantified using RT-qPCR. Multipotency of ASCs for adipogenic, osteogenic, and chondrogenic differentiation was examined by quantifying Oil Red O and Alizarin Red S staining, alkaline phosphatase activity (ALP), and expression of differentiation relative markers. All data were statistically analyzed using ANOVA. RESULTS: RP fat-derived ASCs showed a higher cell proliferation rate compared to SC and LP derived cells. In contrast, ASCs from lipoma displayed a lower proliferation rate and impaired CFU capacities. The expression of CD44, CD90, and CD105 was upregulated in RP and SC derived cells but not in LP cells. RP fat-derived cells displayed a higher adipogenic potential compared to SC and LP cells. Although ASCs from all fat sources showed enhanced ALP activity following osteogenic differentiation, SC fat-derived cells revealed upregulated ALP and bone morphogenetic protein-2 expression together with a higher calcium deposition. We found an enhanced chondrogenic potency of RP and SC fat-derived cells as shown by Alcian blue staining and upregulation of aggrecan (Aggre), cartilage oligomeric matrix protein precursor (COMP), and collagen 2a1 (Col2a1) expression compared to LP. The expression of OPN and CA9 was exclusively upregulated in the ASCs of LP. CONCLUSIONS: The results provide evidence of variation in ASC performance not only between normal fat depots but also compared to LP cells which suggest a different molecular regulation controlling the cell fate. These data provided are useful when considering a source for cell replacement therapy in equine veterinary medicine.

Stem Cell Therapy for Tendon Regeneration: Current Status and Future Directions.

In adults the healing tendon generates fibrovascular scar tissue and recovers never histologically, mechanically, and functionally which leads to chronic and to degenerative diseases. In this review, the processes and mechanisms of tendon development and fetal regeneration in comparison to adult defect repair and degeneration are discussed in relation to regenerative therapeutic options. We focused on the application of stem cells, growth factors, transcription factors, and gene therapy in tendon injury therapies in order to intervene the scarring process and to induce functional regeneration of the lesioned tissue. Outlines for future therapeutic approaches for tendon injuries will be provided.

Effects of controlled hypoxemia or hypovolemia on global and intestinal oxygenation and perfusion in isoflurane anesthetized horses receiving an alpha-2-agonist infusion.

BACKGROUND: Aim of this prospective experimental study was to assess effects of systemic hypoxemia and hypovolemia on global and gastrointestinal oxygenation and perfusion in anesthetized horses. Therefore, we anesthetized twelve systemically healthy warmblood horses using either xylazine or dexmedetomidine for premedication and midazolam and ketamine for induction. Anesthesia was maintained using isoflurane in oxygen with either xylazine or dexmedetomidine and horses were ventilated to normocapnia. During part A arterial oxygen saturation (SaO2) was reduced by reducing inspiratory oxygen fraction in steps of 5%. In part B hypovolemia was induced by controlled arterial exsanguination via roller pump (rate: 38 ml/kg/h). Mean arterial blood pressure (MAP), heart rate, pulmonary artery pressure, arterial and central venous blood gases and cardiac output were measured, cardiac index (CI) was calculated. Intestinal microperfusion and oxygenation were measured using laser Doppler flowmetry and white-light spectrophotometry. Surface probes were placed via median laparotomy on the stomach, jejunum and colon. RESULTS: Part A: Reduction in arterial oxygenation resulted in a sigmoid decrease in central venous oxygen partial pressure. At SaO2 < 80% no further decrease in central venous oxygen partial pressure occurred. Intestinal oxygenation remained unchanged until SaO2 of 80% and then decreased. Heart rate and pulmonary artery pressure increased significantly during hypoxemia. Part B: Progressive reduction in circulating blood volume resulted in a linear decrease in MAP and CI. Intestinal perfusion was preserved until blood loss resulted in MAP and CI lower 51 ± 5 mmHg and 40 ± 3 mL/kg/min, respectively, and then decreased rapidly. CONCLUSIONS: Under isoflurane, intestinal tissue oxygenation remained at baseline when arterial oxygenation exceeded 80% and intestinal perfusion remained at baseline when MAP exceeded 51 mmHg and CI exceeded 40 mL/kg/min in this group of horses. TRIAL REGISTRY NUMBER: 33.14-42,502-04-14/1547.

Bone marrow-derived multipotent mesenchymal stromal cells from horses after euthanasia.

Allogeneic equine multipotent mesenchymal stromal cells (eMSCs) have been proposed for use in regenerative therapies in veterinary medicine. A source of allogeneic eMSCs might be the bone marrow from euthanized horses. The purpose of this study was to compare in vitro characteristics of equine bone marrow derived eMSC (eBM-MSCs) from euthanized horses (eut-MSCs) and from narcotized horses (nar-MSCs). Eut-MSCs and nar-MSCs showed typical eMSC marker profiles (positive: CD44, CD90; negative: CD11a/CD18 and MHCII) and possessed tri-lineage differentiation characteristics. Although CD105 and MHCI expression varied, no differences were detected between eut-MSCs and nar-MSCs. Proliferation characteristics did not differ between eut-MSCs and nar-MSCs, but age dependent decrease in proliferation and increase in MHCI expression was detected. These results suggest the possible use of eut-MSCs for therapeutic applications and production of commercial available eBM-MSC products.

Effect of single intralesional treatment of surgically induced equine superficial digital flexor tendon core lesions with adipose-derived mesenchymal stromal cells: a controlled experimental trial.

BACKGROUND: Adipose tissue is a promising source of mesenchymal stromal cells (MSCs) for the treatment of tendon disease. The goal of this study was to assess the effect of a single intralesional implantation of adipose tissue-derived mesenchymal stromal cells (AT-MSCs) on artificial lesions in equine superficial digital flexor tendons (SDFTs). METHODS: During this randomized, controlled, blinded experimental study, either autologous cultured AT-MSCs suspended in autologous inactivated serum (AT-MSC-serum) or autologous inactivated serum (serum) were injected intralesionally 2 weeks after surgical creation of centrally located SDFT lesions in both forelimbs of nine horses. Healing was assessed clinically and with ultrasound (standard B-mode and ultrasound tissue characterization) at regular intervals over 24 weeks. After euthanasia of the horses the SDFTs were examined histologically, biochemically and by means of biomechanical testing. RESULTS: AT-MSC implantation did not substantially influence clinical and ultrasonographic parameters. Histology, biochemical and biomechanical characteristics of the repair tissue did not differ significantly between treatment modalities after 24 weeks. Compared with macroscopically normal tendon tissue, the content of the mature collagen crosslink hydroxylysylpyridinoline did not differ after AT-MSC-serum treatment (p = 0.074) while it was significantly lower (p = 0.027) in lesions treated with serum alone. Stress at failure (p = 0.048) and the modulus of elasticity (p = 0.001) were significantly lower after AT-MSC-serum treatment than in normal tendon tissue. CONCLUSIONS: The effect of a single intralesional injection of cultured AT-MSCs suspended in autologous inactivated serum was not superior to treatment of surgically created SDFT lesions with autologous inactivated serum alone in a surgical model of tendinopathy over an observation period of 22 weeks. AT-MSC treatment might have a positive influence on collagen crosslinking of remodelling scar tissue. Controlled long-term studies including naturally occurring tendinopathies are necessary to verify the effects of AT-MSCs on tendon disease.

Cutaneous form of maculopapular mastocytosis in a foal.

BACKGROUND: Cutaneous mastocytosis is a rare benign disease occurring in domestic animals and humans. In previous reports, dermal findings in foals were accompanied by systemic mast cell infiltrations, whereas lesions in human cutaneous mastocytosis, including urticaria pigmentosa and solitary mastocytoma, are usually restricted to the skin. OBJECTIVES: To describe a new variant of equine cutaneous maculopapular mastocytosis lacking systemic involvement. ANIMALS: A 2.5-month-old warmblood foal with multiple skin nodules since birth. METHODS: Clinical examination (including haematology, fine needle biopsy and thoracic radiographs), postmortem examination, histopathology and immunohistochemistry. RESULTS: Clinical examination showed 41 skin nodules that contained numerous mast cells as detected by cytology. Macroscopic examination at postmortem examination revealed intradermal circumscribed lesions ranging from 2 to 5 cm in diameter. Histologically, they were composed of well differentiated mast cells with metachromatic granules stained with toluidine blue accompanied by many eosinophils. Immunohistochemically, mast cells had mast cell growth factor receptor c-KIT predominating at the cell surface and intracytoplasmic expression of tryptase. In other organs similar mast cell infiltrations were not detected. CONCLUSIONS AND CLINICAL IMPORTANCE: The case presented here fulfils the criteria of equine cutaneous maculopapular mastocytosis (ECMM), representing a rare entity in foals that is reported to be associated with spontaneous regression, although the long-term prognosis is not known. Unlike in previous reports, lesions described here were restricted to the skin. This may imply that ECMM is primarily a dermal disease sharing similarities with urticaria pigmentosa in young children.

Tracking of autologous adipose tissue-derived mesenchymal stromal cells with in vivo magnetic resonance imaging and histology after intralesional treatment of artificial equine tendon lesions--a pilot study.

BACKGROUND: Adipose tissue-derived mesenchymal stromal cells (AT-MSCs) are frequently used to treat equine tendinopathies. Up to now, knowledge about the fate of autologous AT-MSCs after intralesional injection into equine superficial digital flexor tendons (SDFTs) is very limited. The purpose of this study was to monitor the presence of intralesionally injected autologous AT-MSCs labelled with superparamagnetic iron oxide (SPIO) nanoparticles and green fluorescent protein (GFP) over a staggered period of 3 to 9 weeks with standing magnetic resonance imaging (MRI) and histology. METHODS: Four adult warmblood horses received a unilateral injection of 10 × 10(6) autologous AT-MSCs into surgically created front-limb SDFT lesions. Administered AT-MSCs expressed lentivirally transduced reporter genes for GFP and were co-labelled with SPIO particles in three horses. The presence of AT-MSCs in SDFTs was evaluated by repeated examinations with standing low-field MRI in two horses and post-mortem in all horses with Prussian blue staining, fluorescence microscopy and with immunofluorescence and immunohistochemistry using anti-GFP antibodies at 3, 5, 7 and 9 weeks after treatment. RESULTS: AT-MSCs labelled with SPIO particles were detectable in treated SDFTs during each MRI in T2*- and T1-weighted sequences until the end of the observation period. Post-mortem examinations revealed that all treated tendons contained high numbers of SPIO- and GFP-labelled cells. CONCLUSIONS: Standing low-field MRI has the potential to track SPIO-labelled AT-MSCs successfully. Histology, fluorescence microscopy, immunofluorescence and immunohistochemistry are efficient tools to detect labelled AT-MSCs after intralesional injection into surgically created equine SDFT lesions. Intralesional injection of 10 × 10(6) AT-MSCs leads to the presence of high numbers of AT-MSCs in and around surgically created tendon lesions for up to 9 weeks. Integration of injected AT-MSCs into healing tendon tissue is an essential pathway after intralesional administration. Injection techniques have to be chosen deliberately to avoid reflux of the cell substrate injected. In vivo low-field MRI may be used as a non-invasive tool to monitor homing and engraftment of AT-MSCs in horses with tendinopathy of the SDFT.

Influence of ketamine or xylazine supplementation on isoflurane anaesthetized horses--a controlled clinical trial.

OBJECTIVES: To determine the influence of ketamine or xylazine constant rate infusions on isoflurane requirements, cardiovascular parameters and quality of anaesthesia in horses undergoing elective surgery. STUDY DESIGN: Prospective, matched paired clinical trial. ANIMALS: Fifty four adult Warmblood horses. METHODS: After premedication with acepromazine, xylazine and butorphanol, anaesthesia was induced with ketamine-midazolam and maintained with isoflurane alone (I), isoflurane with either 1 mg kg(-1)  hour(-1) ketamine (IK) or same dose of xylazine (IX). End tidal concentration of isoflurane (Fe'Iso) was adjusted by the same anaesthetist in all horses according to a scoring system. Dobutamine was infused to maintain mean arterial pressure (MAP) ≥70 mmHg. Arterial blood gases, heart rate (HR), respiratory rate, MAP and cardiac output (lithium dilution) were measured. Groups I and IK received xylazine before recovery. Recovery quality was scored. RESULTS: Mean ± SD averaged Fe'Iso (volume%) was significantly lower in IX (0.95 ± 0.07) and IK (0.97 ± 0.08) than in I (1.16 ± 0.13). In group IX, HR was significantly lower and averaged MAP (90 ± 13 mmHg) significantly higher than in groups I (71 ± 7 mmHg) and IK (76 ± 7 mm Hg). Differences in other cardiopulmonary variables did not reach statistical significance. All horses recovered well with best score in group IX. CONCLUSIONS: Both CRIs of xylazine and of ketamine resulted in pronounced reduction of isoflurane requirements and blood pressure support based on routinely monitored parameters. Cardiac output appeared well maintained in all three protocols, but lithium dilution induced errors mean the results are untrustworthy. The work requires repetition with another mode of measurement of cardiac output. CLINICAL RELEVANCE: All three protocols provided good clinical anaesthesia with clinically acceptable cardiovascular effects.

Effect of autologous adipose tissue-derived mesenchymal stem cells on neovascularization of artificial equine tendon lesions.

AIMS: To investigate whether autologous adipose tissue-derived mesenchymal stem cells (AT-MSCs) treatment of tendon lesions increases neovascularization during tendon healing. MATERIALS & METHODS: A standardized surgical model was used to create lesions in both front limb superficial digital flexor tendons (SDFTs) of nine horses. Either AT-MSCs or control substance was injected intralesionally 2 weeks post-surgery. Color Doppler ultrasonography of SDFTs was performed at regular intervals. Horses were euthanized 22 weeks post-treatment and SDFTs were harvested for histology. RESULTS: The color Doppler ultrasonography signal was significantly more extensive at 2 weeks post-treatment and the number of vessels counted on histologic slides was significantly higher at 22 weeks post-treatment in AT-MSC-treated SDFTs. CONCLUSION: Our findings indicate that AT-MSC treatment has a beneficial effect on neovascularization of healing tendons.

Effects of in vivo lidocaine administration at the time of ischemia and reperfusion on in vitro contractility of equine jejunal smooth muscle.

OBJECTIVE: To determine whether administration of lidocaine during ischemia and reperfusion in horses results in concentrations in smooth muscle sufficient to protect against the negative consequences of ischemia-reperfusion injury on smooth muscle motility. ANIMALS: 12 horses. PROCEDURES: Artificial ischemia and reperfusion injury of jejunal segments was induced in vivo in conjunction with lidocaine treatment during ischemia (IRL) or without lidocaine treatment (IR). Isometric force performance was measured in vitro in IRL and IR smooth muscle preparations with and without additional in vitro application of lidocaine. Lidocaine concentrations in smooth muscle were determined by means of high-performance liquid chromatography. To assess the influence of lidocaine on membrane permeability, activity of creatine kinase and lactate dehydrogenase released by in vitro incubated tissues was determined biochemically. RESULTS: In vivo administration of lidocaine allowed maintenance of contractile performance after an ischemia and reperfusion injury. Basic contractility and frequency of contractions were significantly increased in IRL smooth muscle tissues in vitro. Additionally, in vitro application of lidocaine achieved further improvement of contractility of IR and IRL preparations. Only in vitro application of lidocaine was able to ameliorate membrane permeability in smooth muscle of IR and IRL preparations. Lidocaine accumulation could be measured in in vivo treated samples and serum. CONCLUSIONS AND CLINICAL RELEVANCE: In vivo lidocaine administration during ischemia and reperfusion had beneficial effects on smooth muscle motility. Initiating lidocaine treatment during surgery to treat colic in horses may improve lidocaine's prokinetic features by protecting smooth muscle from effects of ischemia and reperfusion injury.

Comparison of the diagnostic value of ultrasonography and standing radiography for pelvic-femoral disorders in horses.

OBJECTIVE: To assess agreement between ultrasonography (transcutaneous and transrectal) and standing radiography in horses with fractures in the pelvic region and disorders of the coxofemoral joint. STUDY DESIGN: Case series. ANIMALS: Warmblood horses (n=23) and 2 ponies. METHODS: Medical records (1999-2008) of equids with pelvic or coxofemoral disorders that had pelvic radiography and ultrasonography were retrieved and results of both techniques compared. RESULTS: Radiography and ultrasonography each identified equal numbers of fractures of the tuber coxa (n=4), ilial shaft (2), ischium (3), femoral neck (2), and osteoarthritis/osis of the coxofemoral joint (6). Fractures of the ilial wing (4) were only identified by ultrasonography not by standing radiography. Of 9 acetabular fractures, 3 were identified on radiographs only, 5 were identified with both modalities. One pubic fracture was identified using ultrasonography and radiography. One acetabular and 1 pubic fracture were only diagnosed on necropsy. CONCLUSIONS: We found reasonable agreement (73%; 24/33) between ultrasonography and standing radiography for diagnosis of pelvic-femoral disorders. Ultrasonography was more useful for ilial wing fractures and radiography for acetabular fractures. CLINICAL RELEVANCE: Ultrasonography is a rapid, safe imaging technique for detecting disorders of the pelvic region with a high diagnostic yield and is a preferred initial approach in horses with severe hindlimb lameness.

Alterations of epidermal proliferation and cytokeratin expression in skin biopsies from heavy draught horses with chronic pastern dermatitis.

We report the historical, clinical and histopathological characteristics of skin lesions in biopsies from 37 heavy draught horses with chronic pastern dermatitis. The skin lesions were divided into four macroscopic groups: scaling (group I, n=5), hyperkeratotic and hyperplastic plaque-like lesions (group II, n=14), nodular skin masses (group III, n=16) and verrucous skin lesions (group IV, n=2). The principal histological findings were hyperkeratosis and epidermal hyperplasia. There was a gradual increase in epidermal hyperplasia from groups I to IV, suggesting that the lesions represent different stages of disease. In all cases, there was perivascular dermatitis dominated by T lymphocytes with an increase in MHC class II-positive dendritic-like cells. Immunohistochemical labelling for cytokeratins CK5/6(4), CK10 and CK14 indicated a change in their expression pattern. This correlated with the degree of epidermal hyperplasia, indicating abnormal differentiation of keratinocytes. There was a statistically significant correlation between the severity of skin lesions and several other factors including increasing age, increasing cannon circumference, prominence of anatomical structures such as fetlock tufts of hairs, ergots and chestnuts, and bulges in the fetlock region.