No abstract

During recent years, cell-based therapies using mesenchymal stem cells (MSC) are reported in equine veterinary medicine with increasing frequency. In most cases, the isolation and in vitro differentiation of equine MSC are described, but their proper immunophenotypic characterization is rarely performed. The lack of a single marker specific for MSC and the limited availability of monoclonal antibodies (mAbs) for equine MSC in particular, strongly hamper this research. In this study, 30 commercial mAbs were screened with flow cytometry for recognizing equine epitopes using the appropriate positive controls to confirm their specificity. Cross-reactivity was found and confirmed by confocal microscopy for CD45, CD73, CD79a, CD90, CD105, MHC-II, a monocyte marker, and two clones tested for CD29 and CD44. Unfortunately, none of the evaluated CD34 clones recognized the equine epitopes on positive control endothelial cells. Subsequently, umbilical cord blood-derived undifferentiated equine MSC of the fourth passage of six horses were characterized using multicolor flow cytometry based on the selected nine-marker panel of both cell surface antigens and intracytoplasmatic proteins. In addition, appropriate positive and negative controls were included, and the viable single cell population was analyzed by excluding dead cells using 7-aminoactinomycin D. Isolated equine MSC of the fourth passage were found to be CD29, CD44, CD90 positive and CD45, CD79a, MHC-II, and a monocyte marker negative. A variable expression was found for CD73 and CD105. Successful differentiation towards the osteogenic, chondrogenic, and adipogenic lineage was used as additional validation. We suggest that this selected nine-marker panel can be used for the adequate immunophenotyping of equine MSC. '

No abstract

Interest in mesenchymal stem cells (MSCs) both for regenerative and reparative therapies in dogs is emerging, as the current treatment options for several conditions often do not result either in the desired clinical outcome or in the patients' return to normal function. In addition, canine MSCs have been evaluated in some experimental and preclinical studies on efficacy and safety testing of novel treatments for humans, since the dog is considered to be a superior model for humans than rodents. Although these MSCs can be derived from several sources, clinical use has favoured bone marrow and adipose tissue because of their relative ease of stem cell recovery and the minimal donor-site morbidity. Before any type of stem cell can be applied clinically, its unequivocal characterization by a set of specific functional or phenotypic markers is crucial. However, no uniform characterization criteria are available for canine MSCs so far. Moreover, although multi-lineage potential of canine MSCs has been demonstrated in a limited number of studies, research on the differentiation potential of MSCs towards tenocytes is still lacking in canine medicine. In contrast, this latter subject has been explored already in human as well as in equine medicine, demonstrating the need for a specific 'niche', i.e. factors with a positive influence on the MSC differentiation. Since most of these factors are still unknown regarding canine MSC, critical basic knowledge is urgently required to motivate and correctly translate the potential therapeutic applications of these stem cells in both dog and man.

Computer-assisted sperm analysis can only provide a rough estimate of sperm concentration and overestimation is likely when drop-filled slides with a coverslip are used. Motility estimates using CASA are highly influenced by the counting chamber; therefore, a complete description of the chamber type used should be provided in semen reports and in scientific articles.