Background: There is limited information relating bronchoalveolar lavage (BAL) cytology and cytokine messenger ribonucleic acid (mRNA) expression in racehorses with inflammatory airway disease (IAD).Hypothesis and Objective: We hypothesize that cytokine expression in BAL cells would correlate with cytology. Thus, we evaluated the mRNA expression of selected cytokines in BAL cells in racehorses with exercise intolerance and lower airway inflammation.Animals: Thirty-one client-owned Standardbred racehorses with exercise intolerance. Methods: Prospective, observational study. Cells were obtained by BAL, and mRNA expression of interleukin (IL)-1b, IL-4, IL-8, tumor necrosis factor (TNF)-a, and interferon (IFN)-g was determined by reverse transcription quantitative polymerase chain reaction (RT-qPCR).Results: Nine horses had normal BAL cell differential cytology (Controls), while 22 horses had evidence of IAD based on BAL fluid cytology. Relative expressions of TNF-a/glyceraldehyde 3-phosphate dehydrogenase (GAPDH; 0.0092 AE 0.010 versus 0.0045 AE 0.005, P 5 .034), IL-4/GAPDH (0.001 AE 0.002 versus 0.0003 AE 0.0003, P 5 .029), and IFN-g/GAPDH (0.0027 AE 0.003 versus 0.0009 AE 0.001, P 5 .028) were greater in horses with IAD compared with controls. Furthermore, IL-4/GAPDH (0.001 AE 0.002 versus 0.0002 AE 0.0003, P o .0001) and IFN-g/GAPDH (0.003 AE 0.003 versus 0.001 AE 0.001, P 5 .002) mRNA expression was increased in horses with increased metachromatic cell counts compared with horses with normal metachromatic cell counts. Only the mRNA expression of IL-1b/GAPDH (1.1 AE 0.7 versus 0.3 AE 0.3, P 5 .045) was increased with airway neutrophilia.Conclusions and Clinical Importance: Differences in gene expression were associated with the presence of IAD and with specific cell types present in airway secretions of Standardbred racehorses with poor performance. These findings suggest that different pathophysiological pathways are implicated in IAD.

Background: Coagulopathies detected in horses with gastrointestinal problems seem to be associated with poor outcome. Plasma D-Dimer concentration is a sensitive test for assessing coagulopathies.Hypothesis: Plasma D-Dimer concentration tested on admission is related to diagnosis and outcome in horses with colic. Animals: Four hundred and ninety three horses referred for evaluation of abdominal pain. Methods: Prospective observational clinical study. Horses were grouped according to diagnosis (medical and surgical intestinal obstructions, ischemic disorders with and without intestinal resection, enteritis, peritonitis), outcome (survivors, nonsurvivors), and number of coagulopathies (normal profile, 1 or 2 coagulopathies, subclinical disseminated intravascular coagulation [DIC]). Blood samples were collected on admission and plasma D-Dimer concentration, clotting times (PT and aPTT), and antithrombin activity were determined. Positive likelihood ratios (LR1) were calculated for evaluation of D-Dimer cut-off values, which were later tested in a logistic regression model.Results: Horses with enteritis or peritonitis had significantly (P o .001) higher plasma D-Dimer concentrations and more severe coagulopathies on admission than horses with other diagnoses. Nonsurvivors also had significantly (P o .001) higher plasma D-Dimer concentrations at presentation than did survivors, and those horses with subclinical DIC on presentation had an odds ratio (OR) 8.6 (95% confidence interval [CI], 3.3-22.5, P o .001) for nonsurvival. Finally, D-Dimer concentrations 44,000 ng/mL had a LR1 of 5.9 and an OR 8.8 (95% CI, 4.5-17.1, P o .001) for nonsurvival.Conclusion and Clinical Importance: Plasma D-Dimer concentration measured on admission can be used to facilitate diagnosis and outcome prediction in horses with colic. A potential cut-off value for nonsurvival was found at approximately 4,000 ng/mL.

SummaryReasons for performing study: Acid-base disturbances are traditionally assessed using the Henderson-Hasselbach equation. The simplified strong ion approach describes more accurately the complex acid-base and electrolyte abnormalities present in endurance horses. Objective: To describe acid-base and electrolytes changes in fit horses competing in a FEI*** 120 km endurance race and to compare the traditional vs. strong ion approaches. Methods: Thirty horses were initially enrolled in the study.Venous blood samples were obtained before the race (n = 25), at the second (n = 29; 65.4 km) and third vet-gates (n = 23, 97.4 km) and upon race completion (n = 17). Blood gas analysis was performed to determine pH, PCO2, PO2, Na Using the strong ion approach, 67% samples showed acid-base disturbances vs. 70% when using the traditional method, but their interpretations only matched in 24% of measurements. Conclusions: A complex acid-base imbalance characterised by a mild strong ion alkalosis (hypochloraemia attenuated by hyperlactataemia), nonvolatile buffer acidosis and compensatory mild respiratory acidosis were present in most horses, although pH did not significantly change during a 120 km endurance race. The strong ion approach to interpretation of acid-base balance should be favoured over the traditional approach in endurance horses, given the frequent and complex alterations in PCO2, SIDm and Atot during a race.