The effects of therapeutic concentrations of gentamicin, amikacin and hyaluronic acid on cultured bone marrow-derived equine mesenchymal stem cells.

REASONS FOR PERFORMING STUDY: Joint inflammation and septic arthritis are both potential complications of intra-articular injections of bone marrow-derived mesenchymal stem cells (BM-MSCs). Clinicians may prophylactically co-inject BM-MSCs admixed with either antimicrobials or hyaluronic acid; however, the effect of these agents on cultured BM-MSCs is unknown. OBJECTIVE: To determine the effects of therapeutic levels of gentamicin, amikacin and hyaluronic acid on cultured equine BM-MSCs in vitro. STUDY DESIGN: In vitro experimental study. METHODS: Equine BM-MSCs from 4 healthy mature horses were isolated. Cultured BM-MSCs from each donor were incubated with gentamicin (150 mg), amikacin (250 mg), hyaluronic acid (22 mg) or 1% penicillin/streptomycin (control) under sterile conditions. Mesenchymal stem cells viability, proliferation, mediator secretion and culture media pH were measured. RESULTS: Incubation of BM-MSCs with gentamicin resulted in >95% MSC death after 45 min, and incubation of BM-MSCs with amikacin resulted in >95% MSC death after 2 h. Incubation of BM-MSCs with hyaluronic acid or penicillin/streptomycin (control) for up to 6 h resulted in sustained BM-MSC viability of 80% and >93%, respectively. All additives resulted in decreased media pH in the first minute; however, the pH then remained constant over the 6 h incubation period. No significant differences in BM-MSC proliferation or mediator secretion between the penicillin/streptomycin (control) and cells treated with hyaluronic acid were observed. CONCLUSION: Therapeutic concentrations of aminoglycoside antimicrobials are toxic to cultured equine BM-MSCs. The effects of hyaluronic acid on cultured MSC viability, proliferation and mediator secretion are minimal. POTENTIAL RELEVANCE: Based on these findings, the mixing of aminoglycoside antimicrobials and cultured equine BM-MSCs prior to therapeutic use is not recommended.

Canine granulocytic anaplasmosis: a review.

Anaplasma phagocytophilum is an emerging pathogen of humans, horses, and dogs worldwide that is transmitted by Ixodid ticks and maintained in a variety of small wild mammal species. Recent studies suggest that multiple strains of A. phagocytophilum may be circulating in wild and domestic animal populations, and these strains may have differential host tropisms and pathogenicity. The organism infects and survives within neutrophils by disabling key neutrophil functions, including neutrophil motility, phagocytosis, the oxidative burst mechanism, and neutrophil-endothelial cell interactions, as well as interfering with neutrophil apoptosis. Coinfections with other tick-borne pathogens may occur, especially Borrelia burgdorferi. A. phagocytophilum causes an acute febrile illness in dogs with lethargy and inappetence. Less frequent signs include lameness, coughing, polydipsia, intermittent vomiting, and hemorrhages. Diagnosis is based on finding morulae within granulocytes in the peripheral blood, the combination of acute and convalescent serology using immunofluorescent antibody techniques, and detection of the DNA of A. phagocytophilum using specific polymerase chain reaction assays. Whether persistent infection or reinfection with A. phagocytophilum occurs after natural infection requires additional study, with most reports suggesting that anaplasmosis is a self-limiting disease in dogs that responds well to a 2-week course of doxycycline therapy.

Collection of equine cord blood and placental tissues in 40 thoroughbred mares.

REASONS FOR PERFORMING STUDY: Stem cells derived from umbilical cord tissue (UCT) and umbilical cord blood (UCB) in human subjects and horses can be obtained in a minimally invasive fashion with successful propagation of mesenchymal stem cells (MSCs). Currently there are no detailed protocols documenting a procedure to harvest UCB and UCT safely for equine stem cell propagation. HYPOTHESIS: UCB and UCT could be collected without harm to mare or foal. OBJECTIVES: To develop a standard and safe method for UCB and UCT collection, and prospectively to compare foal and mare health between groups of animals where tissue was and was not collected. METHODS: This study was conducted at a Thoroughbred breeding facility in central California in 2008. UCB and UCT were collected from 40 mare and foal pairs. Clinical parameters including time for foal to stand and nurse, time for mare to pass the placenta, and foal haematology data at age 24 h were documented and compared to a control group, consisting of the succeeding 40 mare and foal pairs. RESULTS: UCB was obtained successfully from 36 of 40 (90%) mares and UCT from 38 of 40 (95%) mares. Bacterial contamination was documented in 6 out of 36 (16.6%) UCB samples. There were no significant differences in time to stand or nurse for foals or time to pass the placenta for mares, between the experimental and control groups. There were no clinically relevant differences identified in haematological data obtained from foals with and without UCB collection. CONCLUSIONS: UCB and UCT can be harvested safely without harm to mares or foals. POTENTIAL RELEVANCE: UCB and UCT samples collected in an inherently contaminated environment can be successfully disinfected and transported with minimal bacterial overgrowth for use in cell culture to isolate MSCs.