Allogeneic Stem Cells Alter Gene Expression and Improve Healing of Distal Limb Wounds in Horses.

Distal extremity wounds are a significant clinical problem in horses and humans and may benefit from mesenchymal stem cell (MSC) therapy. This study evaluated the effects of direct wound treatment with allogeneic stem cells, in terms of gross, histologic, and transcriptional features of healing. Three full-thickness cutaneous wounds were created on each distal forelimb in six healthy horses, for a total of six wounds per horse. Umbilical cord-blood derived equine MSCs were applied to each wound 1 day after wound creation, in one of four forms: (a) normoxic- or (b) hypoxic-preconditioned cells injected into wound margins, or (c) normoxic- or (d) hypoxic-preconditioned cells embedded in an autologous fibrin gel and applied topically to the wound bed. Controls were one blank (saline) injected wound and one blank fibrin gel-treated wound per horse. Data were collected weekly for 6 weeks and included wound surface area, thermography, gene expression, and histologic scoring. Results indicated that MSC treatment by either delivery method was safe and improved histologic outcomes and wound area. Hypoxic-preconditioning did not offer an advantage. MSC treatment by injection resulted in statistically significant increases in transforming growth factor beta and cyclooxygenase-2 expression at week 1. Histologically, significantly more MSC-treated wounds were categorized as pro-healing than pro-inflammatory. Wound area was significantly affected by treatment: MSC-injected wounds were consistently smaller than gel-treated or control wounds. In conclusion, MSC therapy shows promise for distal extremity wounds in horses, particularly when applied by direct injection into the wound margin. Stem Cells Translational Medicine 2018;7:98-108.

Identification, management and outcome of postoperative hemoperitoneum in 23 horses after emergency exploratory celiotomy for gastrointestinal disease.

OBJECTIVE: To investigate postoperative hemoperitoneum in a population of horses that had surgery for colic. STUDY DESIGN: Retrospective case series. ANIMALS: Horses (n = 23). METHODS: Preoperative, intraoperative, and postoperative information was obtained from medical records (1985-2012) of horses with postoperative hemoperitoneum after emergency exploratory celiotomy. Pre-existing hemoperitoneum during surgery and nonsurgical hemoperitoneum were excluded. RESULTS: Of 4520 horses that had emergency exploratory celiotomy for gastrointestinal disease, 23 horses met inclusion criteria; an incidence of 0.5%. Horse signalment approximated the colic population, although Thoroughbreds were significantly overrepresented. Hemoperitoneum was significantly associated with intestinal resection. Postoperative hemoperitoneum was recognized a mean (± SD) of 1.0 ± 0.7 days after surgery and associated with tachycardia, decreasing hematocrit, incisional drainage, or ultrasonographic identification of swirling, echogenic abdominal fluid. Primary treatments included intravenous fluid therapy (n = 23), colloid support (20), blood transfusion (13), and antifibrinolytic agents (11). Fifteen horses (65%) survived to discharge, which was associated with admission lactate and days of hospitalization. CONCLUSIONS: Postoperative hemoperitoneum is a rare complication of exploratory celiotomy in horses that should be considered when there are signs of abdominal discomfort and declining hematocrit in the early postoperative period. Prognosis is guarded because of potential sequelae of septic peritonitis and adhesion formation.

Pull-through technique for palmar digital neurectomy: forty-one horses (1998-2004).

OBJECTIVES: To report outcome of horses treated for navicular syndrome using a pull-through (PT) technique for palmar digital neurectomy (PDN). DESIGN: Retrospective study. ANIMALS: Horses (n=41) with navicular syndrome (NS). METHODS: Medical records (1998-2002) for horses that had NS and failed to respond to conservative management that had unilateral or bilateral forelimb, biaxial PDN were reviewed. Outcome for up to 6 years was obtained by telephone questionnaire or lameness examination. Survival analysis was used to assess time to recurrence of lameness. RESULTS: One year after PDN, 36 horses (88%) were free of lameness. Mean survival with no lameness after surgery was estimated at 4.14+/-0.33 years (median, 5 years). CONCLUSIONS: PT-PDN technique resulted in soundness for 88% of horses for at least 1 year. PT-PDN was easily and quickly performed without specialized equipment, and had a low incidence of complications. CLINICAL RELEVANCE: The PT technique is an effective and viable alternative surgical method for PDN.