No abstract

Thoracoscopically guided pulmonary wedge resection provides a minimally invasive method for use in obtaining specimens of lung tissues from healthy horses and those with lung disease. This technique may be useful for the diagnosis of diseases of the lungs and thoracic cavity.

Equine laminitis is a crippling condition associated with a variety of systemic diseases. Although it is apparent that the prodromal stages of laminitis involve microvascular dysfunction, little is known regarding the physiology of this vasculature. The aim of the present study was to determine the relative responses of equine laminar arteries and veins to the vasoconstrictor agonists phenylephrine (1 nM-10 microM), 5-HT (1 nM-10 microM), PGF2alpha (1 nM-100 microM), and endothelin-1 (1 pM-1 microM). We have determined that laminar veins were more sensitive, with respect to the concentration of agonist required to initiate a contractile response and to achieve EC(50), for all agonists tested. EC50 values, for veins and arteries, respectively, were 84+/-7 vs. 688+/-42 nM for phenylephrine, 35+/-6 vs. 224+/-13 nM for 5-HT, 496+/-43 nM vs. 3.0+/-0.6 microM for PGF2alpha, and 467+/-38 pM vs. 70.6+/-6.4 nM for endothelin-1. Moreover, when expressed as a percentage of the response to a depolarizing stimulus (80 mM potassium), the maximal contractile response of laminar veins exceeded that for the laminar arteries for each agonist. These results indicate that there may be a predisposition for venoconstriction within the vasculature of the equine digit. While this physiological predisposition for venoconstriction may be important in the regulation of blood flow during exercise, it also may help to explain why laminitis can result from a variety of pathological systemic conditions.

In horses, BWHE administration causes increases in MPO concentration and activity in laminar tissue and skin and the time of increased MPO concentration correlates with emigration of WBCs from the vasculature. These findings support the hypothesis that activation of peripheral WBCs is an early step in the pathogenesis of acute laminitis.

No abstract

BackgroundMesenchymal stem cells (MSCs) produced for clinical purposes rely on culture media containing fetal bovine serum (FBS) which is xenogeneic and has the potential to significantly alter the MSC phenotype, rendering these cells immunogenic. As a result of bovine-derived exogenous proteins expressed on the cell surface, MSCs may be recognized by the host immune system as non-self and be rejected. Platelet lysate (PL) may obviate some of these concerns and shows promising results in human medicine as a possible alternative to FBS. Our goal was to evaluate the use of equine platelet lysate (ePL) pooled from donor horses in place of FBS to culture equine MSCs. We hypothesized that ePL, produced following apheresis, will function as the sole media supplement to accelerate the expansion of equine bone marrow-derived MSCs without altering their phenotype and their immunomodulatory capacity.MethodsPlatelet concentrate was obtained via plateletpheresis and ePL were produced via freeze-thaw and centrifugation cycles. Population doublings (PD) and doubling time (DT) of bone marrow-derived MSCs (n = 3) cultured with FBS or ePL media were calculated. Cell viability, immunophenotypic analysis, and trilineage differentiation capacity of MSCs were assessed accordingly. To assess the ability of MSCs to modulate inflammatory responses, E. coli lipopolysaccharide (LPS)-stimulated monocytes were cocultured with MSCs cultured in the two different media formulations, and cell culture supernatants were assayed for the production of tumor necrosis factor (TNF)-α.ResultsOur results showed that MSCs cultured in ePL media exhibited similar proliferation rates (PD and DT) compared with those cultured in FBS at individual time points. MSCs cultured in ePL showed a statistically significant increased viability following a single washing step, expressed similar levels of MSC markers compared to FBS, and were able to differentiate towards the three lineages. Finally, MSCs cultured in ePL efficiently suppressed the release of TNF-α when exposed to LPS-stimulated monocytes similar to those cultured in FBS.ConclusionePL has the potential to be used for the expansion of MSCs before clinical application, avoiding the concerns associated with the use of FBS.

The goal of this study was to establish an SPIO-based cell-tracking method in an ovine model of tendonitis and to determine if this method may be useful for further study of cellular therapies in tendonitis in vivo. Functional assays were performed on labeled and unlabeled cells to ensure that no significant changes were induced by intracellular SPIOs. Following biosafety validation, tendon lesions were mechanically (n = 4) or chemically (n = 4) induced in four sheep and scanned ex vivo at 7 and 14 days to determine the presence and distribution of intralesional cells. Ovine MSCs labeled with 50 µg SPIOs/mL remained viable, proliferate, and undergo tri-lineage differentiation (p < 0.05). Labeled ovine MSCs remained detectable in vitro in concentrated cell numbers as low as 10 000 and in volumetric distributions as low as 100 000 cells/mL. Cells remained detectable by MRI at 7 days, as confirmed by correlative histology for dually labeled SPIO+/GFP+ cells. Histological evidence at 14 days suggested that SPIO particles remained embedded in tissue, providing MRI signal, although cells were no longer present. SPIO labeling has proven to be an effective method for cell tracking for a large animal model of tendon injury for up to 7 days post-injection. The data obtained in this study justify further investigation into the effects of MSC survival and migration on overall tendon healing and tissue regeneration.

Six healthy, awake, and pharmacologically restrained mature horses were studied in order to define the changes in cardiopulmonary function during and after exploratory thoracoscopy and to determine the presence of postoperative complications occurring 48 hours after thoracoscopy. In a randomised 3 x 3 latin square design with 2 replications, 18 procedures were performed: 6 right (RTH) and 6 left thoracoscopies (LTH) and 6 sham procedures (STH). Prior to each procedure a physical examination and a bronchoalveolar lavage fluid analysis were performed. During thoracoscopy and sham protocols, horses were sedated with a continual drip of detomidine HCl and data were collected at 6 time intervals: T1 (baseline), T2 (10 min detomidine administration), T3 (first 15 min pneumothorax), T4 (5 min recovery from pneumothorax), T5 (second 15 min pneumothorax), and T6 (10 min recovery from the second pneumothorax and detomidine). An endoscopic thoracic examination was conducted during the 2 pneumothorax periods. An identical protocol was followed for sham procedures without surgery or pneumothorax. Data were analysed by ANOVA with time and surgical procedure as main factors. Physical examinations, thoracic radiography and ultrasound, CBC and bronchoalveolar lavage fluid analysis were performed 48 h after thoracoscopy. Heart rate, respiratory rate, and cardiac output decreased following detomidine administration. There was a trend for cardiac output to be lower during thoracoscopy. Mild systemic hypertension was associated with thoracoscopy although there was no effect on pulmonary arterial pressure. Total and pulmonary vascular resistances were increased following detomidine administration. Thoracoscopy caused a further increase in systemic and pulmonary vascular resistances especially during the second pneumothorax. Arterial O2 tension decreased following detomidine administration and was further decreased during the second pneumothorax period. PaO2 values were lower when thoracoscopy was performed on the left rather than the right hemithorax. No significant complications were found during the 48 h follow-up evaluation. A subclinical postoperative pneumothorax occurred in 2 horses, one of which had sustained a lung laceration by the trocar. Thoracoscopy performed in healthy, awake, and pharmacologically restrained horses did not have detrimental cardiopulmonary effects and did not cause postoperative complications within the first 48 h period.