Search

In equine regenerative medicine using bone marrow-derived mesenchymal stem/stromal cells (BM-MSC), the importance of the quality management of BM-MSC has been widely recognized. However, there is little information concerning the relationship between cellular senescence and the stemness in equine BM-MSC. In this study, we showed that stemness markers (NANOG, OCT4, SOX2 and telomerase reverse transcriptase) and colony forming unit-fibroblast apparently decreased accompanied with incidence of senescence-associated ß-galactosidasepositive cells by repeated passage. Additionally, we suggested that down-regulation of cell proliferation in senescent BM-MSC was related to increased expression of cyclin-dependent kinase inhibitor 2B (CDKN2B). On the other hand, forced expression of NANOG into senescent BM-MSC brought upregulation of several stemness markers and downregulation of CKDN2B accompanied with restoration of proliferation potential and osteogenic ability. These results suggested that expression of NANOG was important for the maintenance of the stemness in equine BM-MSC. [ABSTRACT FROM AUTHOR]

The onset of severe injury to the superficial digital flexor tendon (SDFT) is extremely difficult to predict from slight changes in ultrasonographic findings in cases with no apparent clinical signs. This study investigated the relationship between an increased cross-sectional area (CSA) or edema in the subcutaneous tissue around the tendon and the subsequent onset of severe SDFT injury in Thoroughbred racehorses. Horses were classified into three groups based on ultrasound diagnosis (USD) findings: Group A included cases with enlarged tendons; Group B included cases with tendons of normal size but with prominent edema in the peritendinous tissue; and Group C (control group) included cases with no abnormal USD findings. The incidence of subsequent severe tendon injury was significantly higher in the horses in Groups A (25.7%, 28/101) and B (28.3%, 65/212) than in those in Group C (4.9%, 2/41). There were no significant differences in the median period and the median number of races from the first examination to the subsequent tendon injury between Groups A (140 days, 1 race) and B (120 days, 1 race). The results of this study revealed that horses with increased CSA and peritendinous edema are likely to suffer a subsequent severe tendon injury. Also, these two USD findings, i.e., increased CSA and peritendinous edema, indicate the risk of onset of severe SDFT injury. [ABSTRACT FROM AUTHOR]

Rationale: GW1516 is a peroxisome proliferator-activated receptor-d (PPAR-d) agonist that is banned in horseracing and equestrian sports. Long-term detection and longitudinal distribution of GW1516 in the mane of a horse are reported for the first time and this hair analysis could prolong the detection window of GW1516 for doping control. Methods: Mane hairs were divided into three segments (0-7, 7-15, and >15 cm from the cut end) and completely pulverized and homogenized for analysis. The pulverized hair samples were extracted with methanol followed by further purification and the extracts were analyzed by liquid chromatography/electrospray ionization high-resolution mass spectrometry (LC/ESI-HRMS) using a Q-Exactive instrument. This method was successfully validated and applied to postadministration samples to confirm the presence of GW1516 and its metabolites and estimate the uptake amounts of GW1516. Results: After administration of 150 mg of GW1516 to a thoroughbred mare, GW1516 was detected in one of two segments of all mane hairs, and four metabolites, namely GW1516 sulfoxide, GW1516 sulfone, 5-(hydroxymethyl)-4-methyl-2-(4-trifluoromethylphenyl)thiazole (HMTT), and 4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazole-5-carboxylic acid (MTTC), were also identified. The longitudinal distribution analysis results showed that the maximum uptake of GW1516 into hair (approximately 0.05 pg/mg) was observed at around 13 weeks post-administration and GW1516 could be detected and confirmed up to 6 months post-administration. Conclusions: The parent drug GW1516 was identified as the most appropriate monitoring target in equine hair for controlling its misuse in horses. The use of hair analysis could extend the detection time of GW1516 to at least 6 months after the administration of 150 mg of GW1516 to a thoroughbred mare. [ABSTRACT FROM AUTHOR]

The article presents a study that characterized hyaluronan (HA)-degrading activity in the granulation tissue raised in equine superficial digital flexor (SDF) tendonitis. An overview of equine tendonitis is presented. It discusses the normal SDF tendon tissues collected from two adult thoroughbreds, the HA gel zymography results obtained after processing the tendinopathic tissues and the results of the enzymatic and molecular biological analyses performed in the study.

OBJECTIVE To investigate the pharmacokinetics and antihistaminic effects (pharmacodynamics) of olopatadine in a small population of healthy horses after administration via nasogastric tube. ANIMALS 4 healthy adult Thoroughbreds. PROCEDURES Olopatadine (0.1 mg/kg, once) was administered via nasogastric tube. Blood samples were collected at predetermined time points for pharmacokinetic analyses of the drug in plasma. Olopatadine effects were investigated by measurement of cutaneous wheals induced by ID histamine injection (0.1 mL [10 pg]/injection) at predetermined time points. Inhibition effect ratios were calculated on the basis of measured wheal size (area) after versus before olopatadine administration. RESULTS Mean ± SD maximum plasma olopatadine concentration was 48.8 ±11.0 ng/ mL approximately 1.5 hours after administration. Median terminal half-life was 6.11 hours. Mean ± SD maximal effect was 88.2 ± 4.9% inhibition approximately 3.5 hours after drug delivery, and the inhibition effect remained > 80% for 12.5 hours after treatment. No signs of adverse clinical effects were observed. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested olopatadine may have a strong, long-term inhibitory effect against histamine-induced wheals in the skin of horses. Clinical research with a larger number of horses is warranted. [ABSTRACT FROM AUTHOR]