Stem/progenitor cells in non-lactating versus lactating equine mammary gland

The mammary gland is a highly regenerative organ that can undergo multiple cycles of proliferation, lactation, and involution. Based on the facts that (i) mammary stem/progenitor cells (MaSC) are proposed to be the driving forces behind mammary growth and function and (ii) variation exists between mammalian species with regard to physiological and pathological functioning of this organ, we believe that studying MaSC from different mammals is of great comparative interest. Over the years, important data has been gathered on MaSC of men and mice, although knowledge on MaSC in other mammals remains limited. Therefore, the aim of this work was to isolate and characterize MaSC from the mammary gland of horses. Hereby, our salient findings were that the isolated equine cells met the 2 in vitro hallmark properties of stem cells, namely the ability to self-renew and to differentiate into multiple cell lineages. Moreover, the cells were immunophenotyped using markers for CD29, CD44, CD49f, and Ki67. Finally, we propose the mammosphere assay as a valuable in vitro assay to study MaSC during different physiological phases since it was observed that equine lactating mammary gland contains significantly more mammosphere-initiating cells than the inactive, nonlactating gland (a reflection of MaSC self-renewal) and, moreover, that these spheres were significantly larger in size upon initial cultivation (a reflection of progenitor cell proliferation). Taken together, this study not only extends the current knowledge of mammary gland biology, but also benefits the comparative approach to study and compare MaSC in different mammalian species

Review : mesenchymal stem cell therapy in canine osteoarthritis research : 'Experientia Docet' (experience will teach us)

Osteoarthritis (OA) is currently an incurable and progressive condition in dogs causing chronic joint pain and possibly increasing disability. Due to the poor healing capacity of cartilage lesions that occur with OA, development of effective therapeutics is difficult. For this reason, current OA therapy is mostly limited to the management of pain and inflammation, but not directed ad disease modification. In the search for a safe and effective OA treatment, mesenchymal stem cells (MSCs) have been of great interest since these cells might be able to restore cartilage defects. The designs of OA studies on MSC usage, however, are not always consistent and complete, which limits a clear evaluation of MSC efficacy. The general study results show a tendency to improve lameness, joint pain and range of motion in dogs suffering from naturally-occurring OA. Assessment of the cartilage surface demonstrated the ability of MSCs to promote cartilage-like tissue formation in artificially created cartilage defects. Immunomodulatory capacities of MSCs also seem to play an important role in reducing pain and inflammation in dogs. It should be mentioned, however, that in the current studies in literature there are specific design limitations and further research is warranted to confirm these findings

Regenerative skin wound healing in mammals : state-of-the-art on growth factor and stem cell based treatments

Mammal skin has a crucial function in several life-preserving processes such as hydration, protection against chemicals and pathogens, initialization of vitamin D synthesis, excretion and heat regulation. Severe damage of the skin may therefore be life-threatening. Skin wound repair is a multiphased, yet well-orchestrated process including the interaction of various cell types, growth factors and cytokines aiming at closure of the skin and preferably resulting in tissue repair. Regardless various therapeutic modalities targeting at enhancing wound healing, the development of novel approaches for this pathology remains a clinical challenge. The time-consuming conservative wound management is mainly restricted to wound repair rather than restitution of the tissue integrity (the so-called “restitutio ad integrum”). Therefore, there is a continued search towards more efficacious wound therapies to reduce health care burden, provide patients with long-term relief and ultimately scarless wound healing. Recent in vivo and in vitro studies on the use of skin wound regenerative therapies provide encouraging results, but more protracted studies will have to determine whether the effect of observed effects are clinically significant and whether regeneration rather than repair can be achieved. For all the aforementioned reasons, this article reviews the emerging field of regenerative skin wound healing in mammals with particular emphasis on growth factor- and stem cell-based therapies

Relatie tussen huisvesting en fysieke gezondheidsproblemen van paarden: een enquête over de perceptie van paardeneigenaars

The objective of this preliminary study was to investigate the relationship between the housing conditions and the health and welfare of horses. A survey, based on a questionnaire containing 36 multiple choice questions about various aspects of the housing of horses was conducted. A questionnaire was sent via email to approximately 600 horse owners in Flanders. A total of 225 horse owners completed the questionnaire. The study provides a clear picture of the risk factors that horse owners in practice recognize and the link they see between housing related diseases. Although horse owners usually are sufficiently aware of these influences, they are not taken care of in practice. According to fifty percent of the respondents, the major reason is the impracticability of the advice of the veterinarian. According to the horse owners, the main risk factors affecting the health of horses are: draft, the lack of quarantine measures and the presence of (sharp) foreign objects in the stable. As a consequence, more than 50% of the respondents report nasal discharge and coughing as common problems in their horses. Sixty-seven percent of the horse owners are satisfied with the overall management of the stable. However, there is a widespread dissatisfaction with regard to quarantine measures, in case of a disease outbreak (30% of the horse owners) and in case of the introduction of new animals into a group (36%). Fifty percent of the respondents score their own stable infrastructure 8/10 or more while about one out of four is less satisfied (7/10) about the floor and the walls of their stables. The results of this study can help owners and veterinarians to identify housing factors that may increase the risk to health and welfare problems in horses. This should lead to an improved well-being of the modern, often prolonged - housed horse

Tenogenically induced allogeneic mesenchymal stem cells for the treatment of proximal suspensory ligament desmitis in a horse

Suspensory ligament injuries are a common injury in sport horses, especially in competing dressage horses. Because of the poor healing of chronic recalcitrant tendon injuries, this represents a major problem in the rehabilitation of sport horses and often compromises the return to the initial performance level. Stem cells are considered as a novel treatment for different pathologies in horses and humans. Autologous mesenchymal stem cells (MSCs) are well known for their use in the treatment of tendinopathies; however, recent studies report a safe use of allogeneic MSCs for different orthopedic applications in horses. Moreover, it has been reported that pre-differentiation of MSCs prior to injection might result in improved clinical outcomes. For all these reasons, the present case report describes the use of allogeneic tenogenically induced peripheral blood-derived MSCs for the treatment of a proximal suspensory ligament injury. During conservative management for 4 months, the horse demonstrated no improvement of a right front lameness with a Grade 2/5 on the American Association of Equine Practitioners (AAEP) scale and a clear hypo-echoic area detectable in 30% of the cross sectional area. From 4 weeks after treatment, the lameness reduced to an AAEP Grade 1/5 and a clear filling of the lesion could be noticed on ultrasound. At 12 weeks (T-4) after the first injection, a second intra-lesional injection with allogeneic tenogenically induced MSCs and platelet rich plasma was given and at 4 weeks after the second injection (T-5), the horse trotted sound under all circumstances with a close to total fiber alignment. The horse went back to previous performance level at 32 weeks after the first regenerative therapy and is currently still doing so (i.e., 20 weeks later or 1 year after the first stem cell treatment). In conclusion, the present case report demonstrated a positive evolution of proximal suspensory ligament desmitis after treatment with allogeneic tenogenically induced MSCs

Treatment of equine degenerative joint disease with autologous peripheral blood-derived mesenchymal stem cells: a case report

A 5-year-old German Warmblood stallion with chronic lameness, attributable to degenerative joint disease (DJD) of the pastern joint unresponsive to medical treatments, was treated with autologous mesenchymal stem cells (MSC). These MSC were isolated from the peripheral blood (PB) of the patient and injected into the pastern joint, at a concentration of 2.5x10(6) cells, twice with an 8-week interval. The positive response to this stem cell treatment was documented by visual gait evaluation as well as objective pressure plate analyses. This paper is the first to describe the use of autologous PB-derived MSC to treat a horse suffering from chronic DJD. The favorable outcome of this single case may stimulate further research on the use of equine peripheral blood as a source of autologous MSC in equine regenerative medicine

Equine epidermis : a source of epithelial-like stem/progenitor cells with in vitro and in vivo regenerative capacities

Besides the presence of somatic stem cells in hair follicles and dermis, the epidermis also contains a subpopulation of stem cells, reflecting its high regenerative capacity. However, only limited information concerning epidermis-derived epithelial-like stem/progenitor cells (EpSCs) is available to date. Nonetheless, this stem cell type could prove itself useful in skin reconstitution after injury. After harvesting from equine epidermis, the purified cells were characterized as EpSCs by means of positive expression for CD29, CD44, CD49f, CD90, Casein Kinase 2, p63, and Ki67, low expression for cytokeratin (CK)14 and negative expression for CD105, CK18, Wide CK, and Pan CK. Furthermore, their self-renewal capacity was assessed in adhesion as well as in suspension. Moreover, the isolated cells were differentiated toward keratinocytes and adipocytes. To assess the regenerative capacities of EpSCs, six full-thickness skin wounds were made: three were treated with EpSCs and platelet-rich-plasma (EpSC/PRP-treated), while the remaining three were administered carrier fluid alone (PRP-treated). The dermis of EpSC/PRP-treated wounds was significantly thinner and exhibited more restricted granulation tissue than did the PRP-treated wounds. The EpSC/PRP-treated wounds also exhibited increases in EpSCs, vascularization, elastin content, and follicle-like structures. In addition, combining EpSCs with a PRP treatment enhanced tissue repair after clinical application

A feasibility study on the use of equine chondrogenic induced mesenchymal stem cells as a treatment for natural occurring osteoarthritis in dogs

Conventional treatments of osteoarthritis (OA) reduce pain and the inflammatory response but do not repair the damaged cartilage. Xenogeneic peripheral blood-derived equine chondrogenically induced mesenchymal stem cells (ciMSC) could thus provide an interesting alternative. Six client-owned dogs with confirmed elbow OA were subjected to a baseline orthopedic examination, pressure plate analysis, general clinical examination, hematological analysis, synovial fluid sampling, and radiographic examination, and their owners completed two surveys. After all examinations, a 0.9% saline solution (placebo control product=CP) was administered intra-articularly. After 6 weeks, all examinations were repeated, owners again completed two surveys, and equine ciMSCs were administered in the same joint. After another 6 weeks, dogs were returned for a final follow-up. No serious adverse events or suspected adverse drug reactions were present during this study. No significant differences in blood analysis were noted between the CP and ciMSC treatment. Two adverse events were observed, both in the same dog, one after CP treatment and one after ciMSC treatment. The owner surveys revealed significantly less pain and lameness after ciMSC treatment compared to after CP treatment. There was no significant difference in the orthopedic examination parameters, the radiographic examination, synovial fluid sampling, and pressure plate analysis between CP treatment and ciMSC treatment. A single intra-articular administration of equine ciMSCs proved to be a well-tolerated treatment, which reduced lameness and pain according to the owner's evaluations compared to a placebo treatment

Safety and immunomodulatory properties of equine peripheral blood-derived mesenchymal stem cells in healthy cats

Objective: Due to the immunomodulatory properties of mesenchymal stem cells (MSCs) through stimulation of endogenous immune cells by paracrine signals and cell contact, they have been proposed as alternative treatment option for many inflammatory and immune-mediated diseases in veterinary medicine. However, the long-term cultivation possibilities of feline MSCs are currently compromised due to a restricted proliferation capacity. Therefore, the xenogeneic use of equine peripheral blood-derived MSCs (ePB-MSCs) would present an interesting alternative thanks to their superior cultivation properties. To the authors' knowledge, there are currently no safety reports concerning the xenogeneic use of ePB-MSCs in cats. Therefore, the overall goal of this preliminary study was to investigate if ePB-MSCs can safely be administered in healthy cats and by extension evaluating their immunogenic and immunomodulatory properties. Methods: Ten healthy cats were intravenously (i.v.) injected with 3 x 10(5) ePB-MSCs at three time points (T-0, T-1, T-2). All cats were daily inspected by the caretaker and underwent a physical examination with hematological and biochemical analysis at day 0 (T-0), week 2 (T-1), week 4 (T-2) and week 6 (T-3) by a veterinarian. Furthermore, a modified mixed lymphocyte reaction (MLR) was performed at T-0 and T-3 for each cat in order to evaluate immunogenic and immunomodulatory properties of the ePB-MSCs Results: No adverse clinical effects could be detected following repeated i.v. administration of ePB-MSCs in all cats. Significant lower protein (T-1: P-value = 0.002; T-2: P-value > 0.001; T-3: P-value = 0.004) and albumin levels (T-1: P-value = 0.003; T-2: P-value = 0.001) were seen after repeated administration of ePB-MSCs, compared to T-0. However, all biochemical and hematological parameters stayed within clinical acceptance level. In addition, the repeated injections did not induce a cellular immune response before and after repeated ePB-MSCs administration. Furthermore, convincing immunomodulatory properties of ePB-MSCs on feline peripheral blood mononuclear cells were confirmed in the MLR-assay Conclusion: This preliminary study demonstrates that ePB-MSCs can safely be administered in healthy cats and provide a promising alternative for the treatment of various inflammatory diseases in cats