The effect of hypothermia on influx of leukocytes in the digital lamellae of horses with oligofructose-induced laminitis

Sepsis-related laminitis (SRL) is a common complication in the septic/endotoxemic critically-ill equine patient, in which lamellar injury and failure commonly lead to crippling distal displacement of the distal phalanx. Similar to organ injury in human sepsis, lamellar injury in SRL has been associated with inflammatory events, including the influx of leukocytes into the lamellar tissue and markedly increased expression of a wide array of inflammatory mediators at the onset of Obel grade 1 (OG1) laminitis. The only treatment reported both clinically and experimentally to protect the lamellae in SRL, local hypothermia (“cryotherapy”), has been demonstrated to effectively inhibit lamellar expression of multiple inflammatory mediators when initiated at the time of administration of a carbohydrate overload in experimental models of SRL. However, the effect of hypothermia on leukocyte influx into affected tissue has not been assessed. We hypothesized that cryotherapy inhibits leukocyte emigration into the digital lamellae in SRL. Immunohistochemical staining using leukocyte markers MAC387 (marker of neutrophils, activated monocytes) and CD163 (monocyte/macrophage-specific marker) was performed on archived lamellar tissue samples from an experimental model of SRL in which one forelimb was maintained at ambient temperature (AMB) and one forelimb was immersed in ice water (ICE) immediately following enteral oligofructose administration (10\ua0g/kg, n\ua0=\ua014 horses). Lamellae were harvested at 24\ua0h post-oligofructose administration (DEV, n\ua0=\ua07) or at the onset of OG1 laminitis (OG1, n\ua0=\ua07). Both MAC387-positive and CD163-positive cells were counted by a single blinded investigator on images [n\ua0=\ua010 (40× fields/digit for MAC387 and 20\ua0x fields/digit for CD163)] obtained using Aperio microscopy imaging analysis software. Data were assessed for normality and analyzed with a paired t-test and one-way ANOVA with significance set at p\ua

Topical Wound Medications

Topical therapies are used in equine wound healing to clean and decontaminate the wound environment after acute injury and to promote healing and decrease the risk of infection once the wound has initially been treated. Evolving antibiotic resistance has prompted judicious use of systemic antimicrobials, particularly in the treatment of local infections, such as wounds. The use of topical antiseptics to disinfect acute wounds and topical antimicrobials to manage chronic wounds is necessary to achieve successful healing. In addition, many topical medications can alter the wound environment to promote rapid and effective wound healing

Evaluation of post-operative pain after active desufflation at completion of laparoscopy in mares undergoing ovariectomy

The cause of transient post-operative pain in a subset of horses undergoing laparoscopy is unclear. The objective of this study was to evaluate if residual pneumoperitoneum is associated with transient post-operative pain in mares undergoing ovariectomy. Thirty-eight mares undergoing routine standing laparoscopic ovariectomy were randomly allocated into 2 groups. At the completion of laparoscopy, either the abdominal cavity was actively desufflated or the cannulas were opened to achieve ambient pressure before incisional closure. Assessments were performed for 18 hours after surgery using a validated visceral/somatic pain scale for horses. Overall, pain was minimal in both groups (median score 2/39) post-surgery. Active desufflation of the pneumoperitoneum at the completion of laparoscopy approached statistical significance ( = 0.07) in decreasing pain at 12 hours after laparoscopy. However, effects of active desuffation were not significant throughout the monitored 18-hour post-surgery period. We conclude that the decision to actively desufflate at the completion of laparoscopy should be based on surgeon\u27s preference

Effects of recombinant equine somatotropin on wound healing, carbohydrate and lipid metabolism, and endogenous somatotropin responses to secretagogues in geldings

The primary purpose of this experi-ment was to assess the possible beneficial effects of recombinant equine somatotropin (reST) administration on wound healing in adult geldings. The effects of the 21-d reST treatment on carbohydrate and lipid metabolism and on endogenous ST characteristics were monitored as well. Single, full-thickness skin incisions (7.62 × 7.62 cm) were made in the pectoral region of all geldings on d 0. Treated geldings received reST at 20 μg/kg BW i.m., and control geldings received vehicle (10 mM sodium borate) at equivalent volumes daily from d 0 (immediately after surgery) through d 20. Tracings of the wounds were made with acetate transparencies, and wound areas were calculated via a digital analyzer. In addition to once-daily blood samples collected at specified days throughout the treatment period, an i.v. glucose tolerance test was performed on d 16, and three assessments of endogenous ST secretion were performed in the 2 d immediately following the end of treatment: epinephrine administration during the morning of d 21, an exercise test during the afternoon of d 21, and i.v. aspartic acid infusion on d 22. There was no effect (P \u3e .1) of reST treatment on wound healing as assessed by changes in wound areas. Daily plasma ST, IGF-I, glucose, and insulin concentrations were higher (P \u3c .05) and urea-nitrogen concentrations were lower (P \u3c .001) in geldings receiving reST relative to controls. Glucose, NEFA, and insulin concentrations were all higher (P \u3c .01) in reST-treated geldings before glucose infusion on d 16, and the responses to glucose were greater (P \u3c .05) as well. Epinephrine administration increased (P \u3c .02) ST concentrations in control geldings on d 21 but not in reST-treated geldings; a similar suppressive effect of reST treatment was observed for the ST response to exercise (P \u3c .001). After aspartic acid infusion on d 22, reST-treated geldings had a much smaller (P \u3c .001) ST response than did control geldings. In conclusion, reST administered to geldings at 20 μg/kg BW i.m. caused hyperglycemia, hyperinsulinemia, insulin insensitivity, mobilization of fatty acids, and an apparent negative feedback on the pituitary\u27s ST response to various stimuli known to induce ST secretion. However, there was no beneficial effect of reST treatment with the wound model used in this experiment

The effects of bit chewing on borborygmi, duodenal motility, and gastrointestinal transit time in clinically normal horses

OBJECTIVE: To determine the influence of bit chewing on gastrointestinal transit in clinically normal horses. STUDY DESIGN: Prospective crossover designed study. ANIMALS: Six healthy adult horses. METHODS: Horses were assigned randomly to treatment (apple flavored bit) and control (no-bit) groups and studied for 2 × 1-week trial periods with a 2-week washout period between trials. Horses were fasted for 24 h and slowly refed over 3 days. The bit was placed for 20 min every 6 h. Duodenal contractions and borborygmi auscultations were evaluated every 12 h, approximately 5 min following bit placement. Gastrointestinal total transit time (GI TTT) was measured by administering 200 colored beads via stomach tube and then collected in the manure until 50% and 80% were recovered. Measured variables were compared using an ANOVA or Wilcoxon signed-rank test and the P value was noted. RESULTS: The GI TTT was shortened in the bit chewing group (median: 106.37 h, range: 70-171 h) compared to the no-bit group (median: 170.1 h, range: 149-186 h) (P = .0156) at 80% bead passage (only 4/6 horses passed 80%). Borborygmi (P = .8193), duodenal contractions (P = .2605), and 50% bead passage (P = .0781) showed no differences. CONCLUSION: Bit chewing was safe, inexpensive, and well tolerated. Bit chewing shortened GI TTT and might be an adjunct therapy to augment GI TTT. Further clinical studies are warranted. CLINICAL SIGNIFICANCE: Ileus is a common complication following equine abdominal surgery with no current consistently successful treatment. Bit chewing may be a simple and inexpensive way to augment progressive GI motility