Macroscopic, Histologic, and Immunomodulatory Response of Limb Wounds Following Intravenous Allogeneic Cord Blood-Derived Multipotent Mesenchymal Stromal Cell Therapy in Horses.

Limb wounds are common in horses and often develop complications. Intravenous multipotent mesenchymal stromal cell (MSC) therapy is promising but has risks associated with intravenous administration and unknown potential to improve cutaneous wound healing. The objectives were to determine the clinical safety of administering large numbers of allogeneic cord blood-derived MSCs intravenously, and if therapy causes clinically adverse reactions, accelerates wound closure, improves histologic healing, and alters mRNA expression of common wound cytokines. Wounds were created on the metacarpus of 12 horses. Treatment horses were administered 1.51-2.46 × 108 cells suspended in 50% HypoThermosol FRS, and control horses were administered 50% HypoThermosol FRS alone. Epithelialization, contraction, and wound closure rates were determined using planimetric analysis. Wounds were biopsied and evaluated for histologic healing characteristics and cytokine mRNA expression. Days until wound closure was also determined. The results indicate that 3/6 of treatment horses and 1/6 of control horses experienced minor transient reactions. Treatment did not accelerate wound closure or improve histologic healing. Treatment decreased wound size and decreased all measured cytokines except transforming growth factor-ß3. MSC intravenous therapy has the potential to decrease limb wound size; however, further work is needed to understand the clinical relevance of adverse reactions.

Chitosan-based agent use for hemostasis after cryptorchidectomy in a horse.

OBJECTIVE: To document marked hemorrhage as a complication of inguinal cryptorchidectomy and its successful treatment with a novel chitosan-based hemostatic agent. STUDY DESIGN: Case report. ANIMALS: One healthy 5-year old quarter horse cryptorchid. METHODS: The horse was presented for routine unilateral cryptorchidectomy after prior hemicastration. An inguinal approach was made to the abdomen, and the right external pudendal artery was lacerated at the level of the internal inguinal ring, requiring multiple anesthetic events over a 2-week period in attempts to control hemorrhage. A chitosan-based hemostatic agent was packed into the wound to gain control. RESULTS: Chitosan granules placed in the wound successfully controlled the hemorrhage, whereas the use of gauze packing alone failed. There were no immediate or long-term complications to the chitosan granules; the horse was doing well 18 months postoperatively, and the client was satisfied with the outcome. CONCLUSION: Major hemorrhage was demonstrated from the external pudendal artery and caused difficulties because it occurred deep within the inguinal canal during an inguinal cryptorchidectomy. A chitosan-based hemostatic agent was successfully used to achieve hemostasis. CLINICAL SIGNIFICANCE: The external pudendal artery should be avoided in the medial commissure of the inguinal canal. The use of chitosan-based hemostatic agents warrants further investigation in horses because these products may be useful for controlling major hemorrhage from various causes in equine practice.

Sinocutaneous fistula repair with a masseter muscle transposition flap combined with wound matrix and cancellous bone graft in a horse: A new technique.

OBJECTIVE: To describe a new technique to repair a sinocutaneous fistula with a masseter muscle transposition flap. STUDY DESIGN: Case report. ANIMAL: One 13-year-old thoroughbred stallion. METHODS: One 13-year-old stallion with a 3.5 × 6-cm sinocutaneous fistula over the right caudal maxillary sinus was treated with a transpositional masseter muscle flap. This repair consisted of a commercial wound matrix dressing placed directly over the hole in the maxilla and secured with suture material; a cancellous bone graft collected from the right tuber coxa placed on the dressing; and a portion of the superficial layer of the masseter muscle, with its pedicle at the facial crest, transposed dorsally over the bone graft, followed by a rotational skin flap with skin rostral to the fistula to close the defect. RESULTS: Seroma formation and dehiscence of the skin flap occurred, but the transposed muscle flap survived, and the technique resulted in successful closure of the sinocutaneous fistula with excellent cosmetic and functional outcome. CONCLUSION: A chronic maxillary sinocutaneous fistula was successfully treated by using a transposition flap of the masseter muscle and a rotational skin flap with minor complications. CLINICAL IMPACT: Transposition of the superficial layer of the masseter muscle should be considered for a repair of large maxillary sinocutaneous fistulas in horses.

Identification of mRNA of the Inflammation-associated Proteins CXCL8, CXCR2, CXCL10, CXCR3, and ß-Arrestin-2 in Equine Wounded Cutaneous Tissue: a Preliminary Study.

Horses often sustain cutaneous wounds and healing can be prolonged and difficult to treat. Compared to body wounds, limb wounds heal slower and are more likely to develop exuberant granulation tissue. Differences in healing rates and exuberant granulation tissue formation is attributed to abnormal cytokine profiles. CXCL8 and its receptor CXCR2 are involved in acute inflammation whereas CXCL10 and its receptor CXCR3 are involved in inflammation resolution. ß- arrestin-2 regulates inflammation through internalization of G-protein coupled receptors (GPCRs) including CXCR2 and CXCR3. Gene expression of these five inflammation associated proteins have not been previously identified in equine cutaneous tissue and may play a role in dysregulation of inflammation in equine limb wounds. The mRNA expression levels were measured using QuantiGene Plex Assay from cutaneous biopsies collected from surgically created wounds on the limb and thorax on days 0, 1, 2, 7, 14, and 33 from two horses. The mRNA expression levels were measured in mean fluorescent intensity and graphed. We were successful in identifying all five proteins for the first time in equine cutaneous tissue. Preliminary results suggest that there are different expression patterns for CXCL8, CXCR2 and ß-arrestin-2 between the limb and thorax but not for CXCL10 and CXCR3. Differential regulation of CXCL8, CXCR2 and ß-arrestin-2 may further explain why limb wounds heal differently than body wounds and warrants further investigation.

Occurrence of Incisional Complications After Closure of Equine Celiotomies With USP 7 Polydioxanone.

OBJECTIVES: To report the occurrence of, and risk factors associated with, incisional complications of equine ventral median celiotomies closed with USP 7 polydioxanone (7PD). STUDY DESIGN: Retrospective case series. SAMPLE POPULATION: Horses (n = 73; 75 celiotomies). METHODS: Medical records (2000-2010) were retrieved and reviewed for horses that had a ventral celiotomy closed with 7PD and survived ≥14 days. Follow-up (>1 year) was obtained from the medical record, owner, or referring veterinarian. Independent variables were selected based on risk factors identified in previous studies, perceived clinical relevance, and if there were adequate data recorded in the medical record. Statistical analysis, including multivariable logistic regression with a forward-building model process, was performed to evaluate variables associated with incisional complications. RESULTS: One or more incisional complication(s) occurred in 19 celiotomies (25.3%) during hospitalization or after discharge including: drainage (25.3%), infection (12.0%), and partial dehiscence (5.3%). Two of 63 horses (3.2%) available for follow-up developed an incisional hernia. Variables associated with incisional complications after multivariate analysis included: number of days hospitalized, surgery time, postoperative colic, and postoperative fever. CONCLUSION: Overall occurrence of incisional herniation after closure of ventral celiotomies with 7PD was low.

Ex vivo evaluation of carpal flexion after partial carpal arthrodesis in horses.

OBJECTIVE: To determine degrees of flexion after arthrodesis of the antebrachiocarpal (ABC) joint, middle carpal (MC), and carpometacarpal (CMC) joints combined (MC/CMC), and carpometacarpal (CMC) joint alone. STUDY DESIGN: Ex vivo study. ANIMALS: Forelimbs (n = 9) from 2- to 10-year-old Quarter Horses (5), Thoroughbred (2), and American Paint Horse (2). METHODS: Using 2 locking compression plates, 3 partial carpal arthrodesis techniques were performed. Cables and deadweights were connected to limbs and each angle of flexion determined 3 times using a protractor and then averaged. Control measurements were obtained before and after arthrodesis, the techniques randomized with Latin square design. Descriptive data were analyzed with Levene's test, Q-Q plots, ANOVA, and Bonferroni test. RESULTS: Mean ± SD carpal flexion results were: controls 150° ± 8°, CMC arthrodesis 149° ± 9°, MC/CMC arthrodesis 43° ± 7.6°, and ABC arthrodesis 25° ± 6.3°. There was no significant reduction in flexion after a CMC arthrodesis compared with controls (P = .21), but there was after ABC (P < .001) and MC/CMC arthrodesis (P < .001), with the ABC arthrodesis significantly reduced compared with an MC/CMC arthrodesis (P < .001). CONCLUSIONS: Whereas CMC arthrodesis does not affect carpal flexion, CMC/MC and ABC arthrodesis markedly reduce the degree of carpal flexion.

Second carpal bone slab fracture and subluxation of the middle carpal joint in a horse subsequent to arthrodesis of the carpometacarpal joint.

OBJECTIVE: To report complications of arthrodesis of the carpometacarpal (CMC) joint using a drilling technique in an adult horse. STUDY DESIGN: Case report. ANIMALS: Horse (n = 1). METHOD: A 12-year-old Quarter Horse mare with CMC osteoarthritis (CMC-OA) had arthrodesis under general anesthesia in right lateral recumbency. Under fluoroscopic guidance, a 4.5 mm drill bit was inserted at 3 drilling sites 5-6 cm into the CMC joint and was fanned 30-45° in the plane of the joint and 5-10° in the long axis of the limb to destroy articular cartilage and expose the subchondral bone. RESULTS: The horse presented 2 weeks after surgery for severe lameness of the operated limb. A slab fracture of the 2nd carpal bone (C2) and subluxation of the middle carpal (MC) joint was diagnosed. The horse was humanely euthanatized due to poor prognosis. CONCLUSION: The fanning technique of arthrodesis of the CMC joint may lead to fracture of carpal bones, joint instability, and MC joint subluxation. A balance between articular surface destruction and maintenance of joint stability should be achieved when using this technique.

Ex vivo comparison of the biomechanical properties of hand-sewn and stapled jejunoileal anastomoses in horses.

OBJECTIVE: To compare bursting strength, construction time, and anastomotic dimensions of 4 jejunoileal anastomotic techniques. STUDY DESIGN: Experimental ex vivo study. ANIMALS: Adult horses (n = 12). METHODS: Jejunoileal anastomoses were constructed from harvested ileal and distal jejunal segments using a single-layer Lembert technique (1HS), double-layer simple continuous/Cushing technique (2HS), stapled side-to-side technique (SS), or stapled functional end-to-end technique (FEE). Anastomotic construction time was recorded. Bursting pressures (BP), bursting wall tension (BWT), percentage of mean anastomotic luminal diameter reduction, percentage of luminal diameter reduction relative to adjacent ileal and jejunal diameters and stomal length, were calculated. RESULTS: FEE had the shortest construction time. BP of 1HS and 2HS was significantly higher than FEE and SS (P < .001), which were not different from each other (P = .67). There were no significant differences in BP (P = .25) and BWT (P = .21) between 1HS and 2HS. Mean luminal diameter reduction was less for 1HS (25.1%) than for 2HS (34.8%), however, not statistically different (P = .12). Luminal diameter reduction relative to ileal diameter was significantly less for 1HS (15.2%) than for 2HS (28.47%; P = .012). Luminal diameter reduction relative to jejunal diameter was less for 1HS (32.4%) than 2HS (44.6%) but not statistically different; P = .07). Stomal length was significantly larger for SS (9.93 cm) than FEE (7.32 cm; P = .0002). CONCLUSION: 1HS and 2HS jejunoileal anastomosis are equal in strength; however, 1HS results in less relative luminal diameter reduction. SS and FEE have comparable strength but fail at significantly lower BPs than hand-sewn jejunoileal anastomoses.

Management and long-term outcome of partial glossectomy in 2 horses.

Records were reviewed for 2 horses with partial glossectomy, 1 traumatic and 1 elective. According to long-term follow-up by telephone, both horses had recovered well, experiencing only temporary difficulty while eating, and went on to be ridden successfully using mouth bits. Partial glossectomy, therefore, had a favorable prognosis in 2 performance horses.

Gestion et résultat à long terme de la glossectomie partielle chez 2 chevaux. Les dossiers ont été examinés pour 2 chevaux ayant subi une glossectomie partielle, 1 étant une glossectomie traumatique et 1 étant une glossectomie non urgente. Selon le suivi à long terme par téléphone, les deux chevaux se sont bien rétablis, ont éprouvé seulement une difficulté temporaire à manger et ont ensuite pu être montés avec succès en utilisant des mors. Par conséquent, une glossectomie partielle a présenté un pronostic favorable chez 2 chevaux de performance.(Traduit par Isabelle Vallières).

Healing of multiple fractured thoracic dorsal spinous processes in a Quarter horse.

A Quarter horse gelding sustained fracture and displacement of spinous processes T2-T10. Radiographic evidence of healing was seen 3 mo following injury, and at 2 years post-injury all spinous processes had healed and undergone partial re-alignment. This re-alignment has not been reported before.

Evaluation of a minimally invasive arthrodesis technique for the carpometacarpal joint in horses.

OBJECTIVE: To evaluate a minimally invasive technique for arthrodesis of the carpometacarpal (CMC) joint in horses. STUDY DESIGN: Experimental study. ANIMALS: Healthy horses (n=6). METHODS: A 5.5 mm, 3-drill tract arthrodesis technique was evaluated in 1 randomly selected CMC joint in each of 6 normal horses. Peak vertical ground reaction force (GRF) values were recorded before surgery and at 6, 8, and 12 months thereafter. Radiographic and clinical lameness scores were assigned at regular intervals until 12 months after surgery when the horses were euthanatized. Gross and histologic examinations were performed on the treated CMC joints. RESULTS: After surgery, all horses were lame. Clinical resolution of lameness occurred in 2 by 12 months. Mean peak vertical GRF values significantly differed between treated and nontreated limbs at all recorded time points after surgery. Radiographic scores significantly differed from day 0 at all times after surgery, but did not change significantly after 4 months. Intraarticular bony ankylosis only occurred in 2 horses, based on gross, histologic, and microradiographic examination of sagittal sections of the operated CMC joints. CONCLUSION: The 5.5 mm, 3-drill tract arthrodesis technique was considered successful in only 2 of 6 normal CMC joints treated. Greater articular damage may be necessary to achieve arthrodesis in normal horses. Better results may be achieved by technique modification or in horses affected by CMC osteoarthritis.

Comparison of three drilling techniques for carpometacarpal joint arthrodesis in horses.

OBJECTIVE: To evaluate 3 drilling techniques for arthrodesis of the equine carpometacarpal (CMC) joint. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Cadaveric equine forelimbs (n=15). METHODS: Limbs were divided into 3 groups (5 limbs each) to evaluate 3 drilling techniques: (1) use of a 4.5 mm drill bit inserted into the joint through 4 entry points and moved in a fanning motion; (2) a 5.5 mm drill bit inserted through 2 entry points to create 3 nonfanned drill tracts (3 drill technique); and (3) a 4.5 mm drill bit used in a 3 drill technique. The CMC joint was disarticulated after drilling, and cartilage and subchondral bone damage evaluated visually and by gross and microradiographic examination using planimetry. RESULTS: Technique 1 produced significantly more damage of the proximal surface, but significantly less to the subchondral bone of the distal surface. Technique 1 produced the most damage to both the articular cartilage and subchondral bone of the total CMC joint than either of the 3 drill tract techniques; however, the difference between techniques 1 and 2 was not significant. Damage from technique 3 was significantly less than that with techniques 1 or 2. CONCLUSIONS: Techniques 1 and 2 produced the most cartilage and subchondral bone damage with technique 2 changes more equally distributed between proximal and distal joint surfaces. CLINICAL RELEVANCE: Technique 1 (fanning) and 2 (5.5 mm 3 drill tracts) may be preferable to achieve arthrodesis of the CMC joint. Morbidity and efficacy of these arthrodesis techniques need to be evaluated in vivo.

Carpometacarpal osteoarthritis in thirty-three horses.

OBJECTIVE: To describe signalment, clinical, and radiographic changes associated with carpometacarpal osteoarthritis (CMC-OA) and to report long-term outcome. STUDY DESIGN: Case series. ANIMALS: Horses (n=33) with CMC-OA. METHODS: Medical records (1992-2007) of horses diagnosed with CMC-OA were reviewed and signalment, clinical, and radiographic findings retrieved. Owners were contacted for information on the impact of lameness on intended use, response to treatment, progression of lameness, outcome, and owner satisfaction with response to treatment. RESULTS: CMC-OA identified in 39 limbs, occurred predominantly in middle-aged and older Quarter Horses and Arabians, and caused severe lameness that prevented normal use. Characteristic swelling was centered over the 2nd metacarpal bone/2nd carpal bone articulation. Radiographic changes consisted of proliferative new bone, narrowed joint space, and subchondral lysis. Of 20 horses with follow-up, 7 of 14 treated horses were euthanatized within 4 years and 4 of 5 nontreated horses within 3 years. Response to treatment was short lived and considered very poor by most owners. CONCLUSION: CMC-OA seemingly occurs primarily in Quarter Horses and Arabians in our region. Response to conservative treatment is very poor and short-lived with most horses being euthanatized. CLINICAL RELEVANCE: Conventional treatment methods are unsuccessful for treating CMC-OA.

Treatment of carpometacarpal osteoarthritis by arthrodesis in 12 horses.

OBJECTIVE: To evaluate arthrodesis as a treatment for carpometacarpal joint osteoarthritis (CMC-OA). STUDY DESIGN: Case series. ANIMALS: Horses (n=12) with CMC-OA. METHODS: Arthrodesis was facilitated by insertion and fanning of a drill bit into the CMC joint at several (3-5) locations in 15 limbs. Follow-up radiographs were obtained for 7 horses (9 limbs). Outcome was determined by telephone survey of owners based on postoperative pain, return to use, appearance of the limb, and success of treatment. RESULTS: Postoperative pain was slight or moderate in 10 of 12 (83%) horses during the first 30 days, and 11 of 12 (92%) horses were markedly improved by 6 months and capable of returning to work. Radiographically 6 CMC joints had a bony ankylosis at follow-up whereas 3 did not (mean 8.7 months). On long-term follow-up (mean 28.6 months) all horses had reduced severity of lameness, 10 of 12 (83%) were considered "sound," 8 (67%) returned to their original activity, and all owners considered arthrodesis highly successful as a treatment. CONCLUSION: A drilling technique that produced CMC arthrodesis, allowed most horses to return to their original activity and was considered successful by all clients. CLINICAL RELEVANCE: Arthrodesis of the CMC joint should be considered a treatment option for CMC-OA.

The effect of occlusal equilibration on sport horse performance.

The objective of this study was to investigate the effect of routine dental occlusal equilibration treatment on dressage horse performance. Sixteen horses (11 treated; 5 untreated) ridden by a single rider performed a standardized dressage test twice and were scored by two experienced dressage judges according to recognized movements and rider cues. All horses were sedated and a full-mouth speculum was used to facilitate a complete oral examination. Treated horses had dental equilibration performed using a motorized dental instrument. The horses performed a second test 48-hours after dental equilibration, exactly as the baseline test, with the judges and rider blinded as to treatment group. The total test score as well as the individual movement scores were evaluated for equality of variance and statistical tests were applied to determine the influence of treatment. There was no significant improvement in the test score of horses that had received occlusal equilibration.

Management of neck and head injuries.

The horse, a flight animal that is used extensively by man, frequently receives injuries to its neck or head that result mostly from its management and handling. Better facilities, training of the horse, and horsemanship skills of the handler could prevent many of these injuries. Because many body systems can be involved, with potentially major consequences regarding health, performance, and appearance, early recognition of trauma and competent treatment are crucial. Progress has been made in the treatment of some tracheal and esophageal injuries. Severe tracheal trauma and rupture of the esophagus still represent major challenges for the attending veterinarian, however. Lacerations of the head generally heal well, likely because of an abundant blood supply. Thorough yet conservative debridement is necessary, as is accurate reconstruction of the tissues to maintain normal function and an acceptable cosmetic appearance. Fractures of the facial bones can result in complications, such as sequestrum formation, sinusitis, nasolacrimal duct injury,facial deformity, and injury to or entrapment of the globe. An awareness of the treatment methods available can help to diminish the complication rate and to restore a normal or acceptable appearance.

Periapical curettage: an alternative surgical approach to infected mandibular cheek teeth in horses.

OBJECTIVE: To evaluate an alternative surgical method for treating periapical infection of the mandibular cheek teeth of horses. DESIGN: Retrospective study. ANIMALS: Eleven horses (3-13 years) with periapical mandibular tooth infection. METHODS: Hospital records (1992-2002) of horses that had periapical curettage for the treatment of mandibular cheek tooth root infection were retrieved. Clinical signs, radiographic, and surgical reports were reviewed. Outcome was obtained by telephone questionnaire for 7 horses and by physical examination in 2. RESULTS: Eleven horses (14 infected mandibular molariform teeth) had periapical curettage. Two horses were lost to follow-up. Mean follow-up was 41 months; 2 horses had subsequent tooth repulsion, 7 (78%) horses healed completely although 2 horses still had some local mandibular swelling. CONCLUSION: Periapical curettage, which allows alveolar drainage, appears to be a viable treatment option for periapical infections of equine mandibular cheek teeth. CLINICAL RELEVANCE: Periapical curettage can be performed simply, without expensive imaging or surgical equipment, and thus is useful for both referral and first opinion practice.

Preliminary observations on expression of transforming growth factors beta1 and beta3 in equine full-thickness skin wounds healing normally or with exuberant granulation tissue.

OBJECTIVE: To determine whether transforming growth factor (TGF)-beta1 and -beta3 expression differs between equine limb wounds healing normally and those healing with experimentally induced exuberant granulation tissue (EGT). STUDY DESIGN: Six wounds were created on the lateral aspect of both metacarpi of each horse; one forelimb was untreated, and the other was bandaged to stimulate the development of EGT. Sequential wound biopsies allowed comparison of growth factor expression between the two types of wound. ANIMALS: Four horses (2 to 4 years of age; 350 to 420 kg). METHODS: Wounds were assessed grossly, histologically, and by enzyme-linked immunosorbent assay (ELISA) for TGF-beta1 and -beta3 expression at 12 and 24 hours and 2, 5, 10, and 14 days postoperatively. RESULTS: Bandaged wounds developed EGT. In all wounds, TGF-beta1 peaked early and remained elevated at 14 days. Peak TGF-beta1 concentration was higher in wounds with EGT, but not significantly so. Expression of TGF-beta3 differed from TGF-beta1, with peak TGF-beta3 concentrations being delayed. Concentrations of TGF-beta3 were higher in wounds healing normally, but this difference was not significant. CONCLUSIONS: During both normal and exuberant wound repair, the expression of TGF-beta1 occurred earlier than TGF-beta3 expression. Wounds healing with EGT tended to have higher concentrations of fibrogenic TGF-beta1 and lower concentrations of antifibrotic TGF-beta3 than wounds healing normally, although these differences were not statistically significant. CLINICAL RELEVANCE: This study suggests that the production of EGT in bandaged wounds may be related to increased expression of fibrogenic TGF-beta1 and decreased expression of antifibrotic TGF-beta3. Further investigation of the roles of TGF-beta1 and -beta3 may be important in understanding the molecular control of EGT in horses.

Temporal localization of immunoreactive transforming growth factor beta1 in normal equine skin and in full-thickness dermal wounds.

OBJECTIVE: To describe the localization of immunoreactive transforming growth factor (TGF)-beta1 in both normal skin and full-thickness dermal wounds of the limb and the thorax of the horse. STUDY DESIGN: Six full-thickness excisional wounds were created on the lateral aspect of one metacarpal region and on the midthoracic area of each horse. Sequentially collected tissue specimens from wound margins were assessed for TGF-beta1 expression by immunohistochemistry. ANIMALS: Four horses (2 to 4 years of age). METHODS: A neutralizing monoclonal anti-human TGF-beta1 antibody was used to detect the spatial expression of TGF-beta1 protein by immunohistochemical localization in biopsies obtained before wounding and at 12 and 24 hours, and 5, 10, and 14 days. RESULTS: No differences in localization of immunoreactive TGF-beta1 were detected between limb and thorax, for either intact skin or wounds. Unwounded epidermis stained moderately for TGF-beta1 protein throughout all layers, whereas the dermis was relatively devoid of immunoreactivity. During the acute stage of repair, migrating epithelium lost its stain, whereas cells of epidermal appendages remained strongly immunoreactive. The epithelium recovered its TGF-beta1 immunoreactivity during wound remodeling, although cells of the stratum corneum remained negative. Macrophages of the inflammatory exudate had positive cytoplasmic staining that diminished with time. Immunoreactivity of granulation tissue fibroblasts was evident early on and increased throughout the repair process. CONCLUSIONS: TGF-beta1 is constitutively expressed in normal, unwounded equine epithelium. Its expression is upregulated within the skin on injury and is associated with the cells involved in wound repair. CLINICAL RELEVANCE: A more precise understanding of the temporal and spatial expression of TGF-beta1 during wound repair in horses should provide the groundwork for possible future manipulations of both normal and aberrant tissue repair.