Guidelines to Analyze Preclinical Studies Using Perinatal Derivatives

The last 18 years have brought an increasing interest in the therapeutic use of perinatal derivatives (PnD). Preclinical studies used to assess the potential of PnD therapy include a broad range of study designs. The COST SPRINT Action (CA17116) aims to provide systematic and comprehensive reviews of preclinical studies for the understanding of the therapeutic potential and mechanisms of PnD in diseases and injuries that benefit from PnD therapy. Here we describe the publication search and data mining, extraction, and synthesis strategies employed to collect and prepare the published data selected for meta-analyses and reviews of the efficacy of PnD therapies for different diseases and injuries. A coordinated effort was made to prepare the data suitable to make statements for the treatment efficacy of the different types of PnD, routes, time points, and frequencies of administration, and the dosage based on clinically relevant effects resulting in clear increase, recovery or amelioration of the specific tissue or organ function. According to recently proposed guidelines, the harmonization of the nomenclature of PnD types will allow for the assessment of the most efficient treatments in various disease models. Experts within the COST SPRINT Action (CA17116), together with external collaborators, are doing the meta-analyses and reviews using the data prepared with the strategies presented here in the relevant disease or research fields. Our final aim is to provide standards to assess the safety and clinical benefit of PnD and to minimize redundancy in the use of animal models following the 3R principles for animal experimentation.

Platelet-rich plasma and ovarian quiescence: a bovine in vitro model for regeneration of the ovary

CONTEXT

Ovarian quiescence can be due to hormonal deficiency usually caused by apoptosis of granulosa cells responsible for oestrogen synthesis.

AIM

This study evaluated the regenerative effect of platelet rich plasma (PRP) on bovine in vitro models to understand its effect on granulosa cells.

METHODS

Quiescent and healthy ovarian sections were cultured in the presence/absence of PRP for 72h and, at different times (0, 24, 48 and 72h), hematoxylin-eosin and immunohistochemical detection of Ki-67 were performed. Additionally, granulosa cells collected from healthy bovine ovaries were stressed with 100ng/mL of lipopolysaccharide (LPS) in presence/absence of PRP and evaluated at 0, 4, 8 and 24h for apoptosis by acridine orange and propidium iodide staining. Enzyme-linked immunosorbent assay tests were performed to evaluate oestrogen (E2) and anti-Müllerian hormone (AMH) concentrations on cultures of ovarian slices and granulosa cells.

KEY RESULTS

In slides of quiescent ovaries treated with PRP, a marked and widespread positivity to Ki-67 was expressed by 40-60% of the follicular wall cells at 48h of culture. Levels of E2 and AMH were significantly higher compared to untreated quiescent samples reaching the levels of healthy control samples. PRP counteracted the LPS effect and apoptosis (at 24h, there were 93.44±3.51% live cells with LPS+PRP compared to 37±1.32% with LPS) and significantly increased concentrations of E2 and AMH.

CONCLUSIONS

PRP can stimulate granulosa cell proliferation and counteract inflammatory processes in vitro.

IMPLICATIONS

This treatment could improve the reproductive ability of quiescent females.

Amniotic Mesenchymal-Derived Extracellular Vesicles and Their Role in the Prevention of Persistent Post-Breeding Induced Endometritis

Persistent post-breeding induced endometritis (PPBIE) is considered a major cause of subfertility in mares. It consists of persistent or delayed uterine inflammation in susceptible mares. There are many options for the treatment of PPBIE, but in this study, a novel approach aimed at preventing the onset of PPBIE was investigated. Stallion semen was supplemented with extracellular vesicles derived from amniotic mesenchymal stromal cells (AMSC-EVs) at the time of insemination to prevent or limit the development of PPBIE. Before use in mares, a dose–response curve was produced to evaluate the effect of AMSC-EVs on spermatozoa, and an optimal concentration of 400 × 106 EVs with 10 × 106 spermatozoa/mL was identified. At this concentration, sperm mobility parameters were not negatively affected. Sixteen susceptible mares were enrolled and inseminated with semen (n = 8; control group) or with semen supplemented with EVs (n = 8; EV group). The supplementation of AMSC-EVs to semen resulted in a reduction in polymorphonuclear neutrophil (PMN) infiltration as well as intrauterine fluid accumulation (IUF; p < 0.05). There was a significant reduction in intrauterine cytokine levels (p < 0.05) for TNF-α and IL-6 and an increase in anti-inflammatory IL-10 in mares in the EV group, suggesting successful modulation of the post-insemination inflammatory response. This procedure may be useful for mares susceptible to PPBIE.

Extracellular vesicles from seminal plasma to improve fertilizing capacity of bulls

Seminal plasma contains extracellular vesicles (EVs) that vehicle RNA, proteins, and other molecules able to influence the biological function of sperm. The aim of this study was to improve the fertilizing capacity of male gametes of low-fertility bulls using EVs isolated by ultracentrifugation from the seminal plasma of a bull of proven fertility. After dose-response curve, 10×106 sperm of low-fertility bulls were co-incubated for an hour with 400×106 EVs/ml. In addition, it has been verified that the incorporation of EVs, which takes place in the sperm midpiece, is maintained for 5 hours and even after cryopreservation. Subsequently, the spermatozoa of low-fertility bulls, with EVs incorporated, were used for the in vitro production of embryos. The rate of blastocyst at seventh day yield in vitro, with the use of sperm with EVs incorporated, increased by about twice the yield obtained with the same sperm in the absence of EVs: bulls having an average embryonic yield of 6.41±1.48%, 10.32±4.34% and 10.92±0.95% improved their yield to 21.21±1.99%, 22.17±6.09% and 19.99±5.78%, respectively (P<0.05). These encouraging results suggest that it might be possible to keep breeding bulls with poor fertility. Further studies will be needed to evaluate the in vivo fertility of sperm treated with EVs and understand how the content of EVs is involve in the sperm-vesicle interaction and in the improved sperm performance.

Application of Perinatal Derivatives in Ovarian Diseases

Reproductive diseases could lead to infertility and have implications for overall health, most importantly due to psychological, medical and socio-economic consequences for individuals and society. Furthermore, economical losses also occur in animal husbandry. In both human and veterinary medicine, hormonal and surgical treatments, as well as assisted reproductive technologies are used to cure reproductive disorders, however they do not improve fertility. With ovarian disorders being the main reproductive pathology in human and bovine, over the past 2 decades research has approached regenerative medicine in animal model to restore normal function. Ovarian pathologies are characterized by granulosa cell and oocyte apoptosis, follicular atresia, decrease in oocyte quality and embryonic development potential, oxidative stress and mitochondrial abnormalities, ultimately leading to a decrease in fertility. At current, application of mesenchymal stromal cells or derivatives thereof represents a valid strategy for regenerative purposes. Considering their paracrine/autocrine mode of actions that are able to regenerate injured tissues, trophic support, preventing apoptosis and fibrosis, promoting angiogenesis, stimulating the function and differentiation of endogenous stem cells and even reducing the immune response, are all important players in their future therapeutic success. Nevertheless, obtaining mesenchymal stromal cells (MSC) from adult tissues requires invasive procedures and implicates decreased cell proliferation and a reduced differentiation capacity with age. Alternatively, the use of embryonic stem cells as source of cellular therapeutic encountered several ethical concerns, as well as the risk of teratoma formation. Therefore, several studies have recently focussed on perinatal derivatives (PnD) that can be collected non-invasively and, most importantly, display similar characteristics in terms of regenerating-inducing properties, immune-modulating properties and hypo-immunogenicity. This review will provide an overview of the current knowledge and future perspectives of PnD application in the treatment of ovarian hypofunction.

Physiological Parameters to Identify Suitable Blood Donor Cows for Preparation of Platelet Rich Plasma

Simple Summary

Platelet rich plasma is a biological product obtained from blood and used for regenerative treatments of different pathologies. It is characterized by a high concentration of platelets (at least 3 times the physiological level) containing many growth factors with anti-inflammatory, bactericidal and regenerative properties. In human medicine, PRP is used in an autologous way, it means that the blood donor is also the recipient. In veterinary medicine, PRP is used to treat different diseases or lesions and in bovine species to treat mastitis. In this context, the opportunity to have PRP ready to use, stored from donor cows of the same farm where it will be used, would be very useful in treating this pathology immediately when it occurs. For this purpose, the present research aimed to detect parameters useful to identify the most suitable cows to be used as blood donors to obtain the highest yield of PRP (milliliters of PRP obtained with respect to milliliters of initial blood). Our results showed that blood collection from the mammary vein within three months of parturition, from nonpregnant cows at 5 years of age, but not the blood collection season, were associated with a high yield of PRP.

Abstract

Platelet rich plasma (PRP) has been shown to be beneficial in the treatment of bovine mastitis, with an action comparable to that of antibiotics. Autologous treatment is feasible in experimental conditions but is difficult to apply in field conditions, particularly in acute mastitis. The ideal scenario would be to have heterologous PRP stored on every farm so that it is readily available when needed. In this paper, we analysed data collected during bovine mastitis treatment with heterologous PRP produced by casual donor cows on several farms. We tried to identify parameters which might be useful to identify the most suitable cows to be used as blood donors, to obtain the highest yield of PRP. Variables considered for each animal were the age, the parity, the date of the last parturition, the season of blood collection, the site of blood collection (jugular or mammary vein) and the reproductive status e.g., pregnant or not pregnant. There were statistically significant differences for all the variables considered from the 135 blood cows, except for the blood collection season. The highest yield of PRP was associated with nonpregnancy blood collection within three months of parturition, parity 3 or 4, and blood collection from the mammary vein.

Platelet Rich Plasma for Regenerative Medicine Treatment of Bovine Ovarian Hypofunction

Recent studies on cull cows have shown that ovarian abnormalities, particularly ovarian insufficiency, are the main cause of reproductive failure. The aim of this study was to treat bovine ovarian failure with intraovarian administration of autologous platelet rich plasma (PRP), which is rich in growth factors, chemokines, and cytokines that could stimulate follicular growth and steroidogenesis. Twelve cows with ovarian hypofunction were enrolled in the study and they were randomly allocated in control group (CTR) and treated group (six animal for group). In the treated group, only five animals received the PRP treatment because intraovarian administration was hindered in one by a rectovaginal fistula. Animals of control group were treated by intraovarian administration of physiological solution. In the 4 weeks after PRP injection, a mild to strong increase in progesterone (PRG) concentrations was detected in four of the five cows treated. Artificial insemination (AI) resulted in four pregnancies that are still ongoing (7th month). Intraovarian administration of PRP improved ovarian function after 2 months of treatment. This effect may be due to reduction of follicular atresia or to revitalization of dormant oocytes allowing restoration of fertility.

Large Animal Models in Regenerative Medicine and Tissue Engineering: To Do or Not to Do

Rapid developments in Regenerative Medicine and Tissue Engineering has witnessed an increasing drive toward clinical translation of breakthrough technologies. However, the progression of promising preclinical data to achieve successful clinical market authorisation remains a bottleneck. One hurdle for progress to the clinic is the transition from small animal research to advanced preclinical studies in large animals to test safety and efficacy of products. Notwithstanding this, to draw meaningful and reliable conclusions from animal experiments it is critical that the species and disease model of choice is relevant to answer the research question as well as the clinical problem. Selecting the most appropriate animal model requires in-depth knowledge of specific species and breeds to ascertain the adequacy of the model and outcome measures that closely mirror the clinical situation. Traditional reductionist approaches in animal experiments, which often do not sufficiently reflect the studied disease, are still the norm and can result in a disconnect in outcomes observed between animal studies and clinical trials. To address these concerns a reconsideration in approach will be required. This should include a stepwise approach using in vitro and ex vivo experiments as well as in silico modeling to minimize the need for in vivo studies for screening and early development studies, followed by large animal models which more closely resemble human disease. Naturally occurring, or spontaneous diseases in large animals remain a largely untapped resource, and given the similarities in pathophysiology to humans they not only allow for studying new treatment strategies but also disease etiology and prevention. Naturally occurring disease models, particularly for longer lived large animal species, allow for studying disorders at an age when the disease is most prevalent. As these diseases are usually also a concern in the chosen veterinary species they would be beneficiaries of newly developed therapies. Improved awareness of the progress in animal models is mutually beneficial for animals, researchers, human and veterinary patients. In this overview we describe advantages and disadvantages of various animal models including domesticated and companion animals used in regenerative medicine and tissue engineering to provide an informed choice of disease-relevant animal models.

Case Report: Use of Amniotic Microvesicles for Regenerative Medicine Treatment of a Mare With Chronic Endometritis

Chronic endometritis is an inflammation in the inner layer of uterine mucosa, with or without an infectious process, which affects the animal's fertility but not its general health. A variety of treatments has been adopted over the years but to date, no effective cures have been able to renew the injured tissue. Since the defects in the fetal-maternal communication are caused by degenerative changes due to chronic endometrial inflammation, our working hypothesis was a new approach to this disease by the regenerative medicine using amniotic derived microvesicles (MVs) for their anti-inflammatory and regenerative effects. The MVs are responsible for horizontal transfer of genetic materials, including microRNA (miRNAs) that are involved in paracrine communication between origin cells and target cells. Thus, intrauterine MV infusion may be beneficial in degenerative chronic endometritis and in the fetal–maternal talk. The selected mare was an 11-year-old Friesian, with a history of failed pregnancies despite numerous insemination attempts. Punctual and evident heats characterized the reproductive history, but no insemination attempts had been made for many years. The first (failed) insemination was when the mare was 9-years-old. In the next two reproductive seasons, other attempts were made at regular intervals but none was successful. After a final insemination attempt using a stallion of proven fertility, the collection of an 8-day old embryo suggested that the mare was affected by implantation failure related to endometritis. The mare was treated with two cycles of intrauterine administration of amniotic-derived MVs. The success of the intrauterine administration of MVs was demonstrated by an improvement in the classification of endometritis and in a successful artificial insemination (AI) with implantation of an embryo, as detected at day 14 and with a pregnancy that is still ongoing. Probably, MVs were able to restore the injured endometrium and re-establish the proper communication for a successful embryo implantation.

Effect of relaxin on cryopreserved beef bull semen characteristics

This study aimed to improve the quality of cryopreserved beef bull (Piedmontese) semen by incorporation of relaxin in diluted semen before cryopreservation procedures. Semen samples were collected from 4 proven fertile bulls, using artificial vagina, once per week for 8 consecutive weeks and pooled together then diluted with Bullxcell® extender, and supplemented with different concentrations of relaxin (0 (control), 25, 50 and 100 ng/ml) before cooling, equilibration and freezing procedures. Frozen semen was thawed and assessed for motility by Computer-Assisted Sperm Analysis and vitality parameters such as acrosome, plasma membrane and DNA integrities, apoptosis, mitochondrial membrane potential, mucus penetration and SOD activity. The developmental potential of bovine embryos produced in vitro by using relaxin-treated was also investigated. In the present study, 50 and 100 ng/ml relaxin incorporation in extended bull semen before cryopreservation induced a reduction of sperm motility immediately after thawing (0h), whereas, during long incubation periods (1-2 h), relaxin showed a significant positive effect on sperm quality by improving the sperm motility and velocity parameters. Interestingly, sperm vitality was improved by 25 and 100 ng/ml relaxin and the blastocyst developmental rate was significantly increased in the 25 ng/ml relaxin group compared with controls (52/118, 44.0% vs. 32/116, 27.6%, respectively). These findings suggest a potential use of relaxin at the doses tested in the present study as an additive in the cryopreservation media of bull semen to improve sperm quality.

Priming with inflammatory cytokines is not a prerequisite to increase immune-suppressive effects and responsiveness of equine amniotic mesenchymal stromal cells

BACKGROUND

Equine amniotic mesenchymal stromal cells (AMSCs) and their conditioned medium (CM) were evaluated for their ability to inhibit in vitro proliferation of peripheral blood mononuclear cells (PBMCs) with and without priming. Additionally, AMSC immunogenicity was assessed by expression of MHCI and MHCII and their ability to counteract the in vitro inflammatory process.

METHODS

Horse PBMC proliferation was induced with phytohemagglutinin. AMSC priming was performed with 10 ng/ml of TNF-α, 100 ng/ml of IFN-γ, and a combination of 5 ng/ml of TNF-α and 50 ng/ml of IFN-γ. The CM generated from naïve unprimed and primed AMSCs was also tested to evaluate its effects on equine endometrial cells in an in vitro inflammatory model induced by LPS. Immunogenicity marker expression (MHCI and II) was evaluated by qRT-PCR and by flow cytometry.

RESULTS

Priming does not increase MHCI and II expression. Furthermore, the inhibition of PBMC proliferation was comparable between naïve and conditioned cells, with the exception of AMSCs primed with both TNF-α and IFN-γ that had a reduced capacity to inhibit T cell proliferation. However, AMSC viability was lower after priming than under other experimental conditions. CM from naïve and primed AMSCs strongly inhibited PBMC proliferation and counteracted the inflammatory process, rescuing about 65% of endometrial cells treated by LPS.

CONCLUSION

AMSCs and their CM have a strong capacity to inhibit PBMC proliferation, and priming is not necessary to improve their immunosuppressive activity or reactivity in an inflammatory in vitro model.

88 MicroRNA profile of invitro bovine embryos cultured in the presence of amniotic extracellular vesicles shifts toward invivo-collected blastocysts

The absence of maternal-embryo signals could be an important cause of the poor pregnancy rates of invitro-produced embryos, compared with those collected invivo. In the context of paracrine communication, co-culture of embryo with amniotic-derived extracellular vesicles (EVs) improved their quality compared with control (CTR) (Perrini and Lange Consiglio 2018 Reprod. Fertil. Dev. 30, 658-671), and after cryopreservation, provided higher invitro embryo hatching and recipient pregnancy rate (Lange-Consiglio et al. 2019 Reprod. Fertil. Dev. 31, 155). After these results, the aim of this study was to evaluate microRNA (miRNA) profiling of invitro-produced blastocysts with or without EV supplementation, using invivo-produced blastocysts as CTR. Invitro embryos were produced based on our protocol (Perrini and Lange Consiglio 2018 Reprod. Fertil. Dev. 30, 658-671) with or without 100×106 EVsmL−1 in synthetic oviductal fluid with amino acids (SOFaa) on Day 5 post-fertilisation (Perrini and Lange Consiglio 2018 Reprod. Fertil. Dev. 30, 658-671). Grade 1 blastocysts (B7) were immediately snap frozen in liquid nitrogen for genomic study. These embryos were obtained from three replicates. Invivo embryos were obtained from three cows superovulated by Folltropin and inseminated by the same cryopreserved semen. After flushing, only B7 were snap frozen for genomic study. Samples for RNA isolation were obtained from 3 pools of 10 embryos each for each condition (vivo, vitro-CTR, and vitro+EVs). Total RNA was isolated by a NucleoSpin1 miRNA kit. Concentration and quality of RNA were determined by an Agilent 2100 Bioanalyzer. Libraries were prepared using TruSeq Small RNA Library Preparation kits (Illumina). Differential expression analyses between samples were run with the Bioconductor edgeR package (false discovery rate&lt;0.05). MicroRNA cluster analysis was performed with Genesis. The average quantity of total RNA extracted from each pool was 3.5ng. Our results show that the miRNAs identified were 1.74E5, 2.3E5, and 3.6E5 for vivo, vitro-CTR, and vitro+EVs, respectively. Principal component analysis calculated on differentially expressed miRNAs showed a separation of the three groups with a distinctive miRNA trait. The miRNAs differentially expressed among three comparisons (vivo vs. vitro-CTR, vivo vs. vitro+EVs, and vitro-CTR vs. vitro+EVs) were 20, 15, and 2, respectively. Principal component 1, which explains 62.4% of the variance, clearly separates invivo- and invitro-produced embryos even if EV addition seems to ameliorate the effect of invitro production, and this agrees with the embryo quality and pregnancy rate after EV supplementation (Perrini and Lange Consiglio 2018 Reprod. Fertil. Dev. 30, 658-671; Lange-Consiglio et al. 2019 Reprod. Fertil. Dev. 31, 155). Indeed, vitro-CTR and vitro+EVs embryos differ significantly for two miRNAs (miR-130a, miR-181b) that are found to be higher in our vitro-CTR embryos compared with vitro+EV ones. The miR-181b was also found to be higher in degenerate bovine embryos compared with good blastocysts (Kropp et al. 2014 Front. Genetics 24, 91). In conclusion, this is the first study reporting the complete miRNA profiling of invitro blastocysts compared with those obtained invivo. The addition of EVs during invitro production seems to influence the expression of specific miRNAs involved in the success of embryo implantation.

Antimicrobial Effects of Conditioned Medium From Amniotic Progenitor Cells in vitro and in vivo: Toward Tissue Regenerative Therapies for Bovine Mastitis

There is increasing evidence to suggest that, in addition to their regenerative effect, mesenchymal stromal cells (MSCs), and their secretome have an anti-inflammatory and antimicrobial role in the innate immune response in conditions such as sepsis. However, there is no published information on the effect of MSCs in bovine mastitis. Mastitis often results in extensive tissue damage due to multi-microorganism co-infection. This study investigated the ability of amniotic-derived conditioned medium (CM), in vitro and in vivo, to counteract microbial action and restore healthy tissue capable of milk production. Following determination of a dose–response curve, 10,000 colony-forming units (CFU) of Staphylococcus aureus (S. aureus) were inoculated into bovine mammary epithelial cell culture with and without 10% CM (supplemented either at the time of bacteria inoculation or after 4 h). Acridine orange staining was used to assess cell viability/apoptosis. Additionally, an in vivo study was performed using 48 dairy cows with acute and chronic mastitis, treated with CM (treated group) or antibiotics (control group). In vitro results showed that CM can attenuate bacterial growth, as evaluated by the number of CFU. After 24 h of culture with S. aureus, 89.67% of mammary epithelial cells treated with CM were still alive, whereas all cells cultured without CM were dead. Rates of epithelial cell survival (60.67%) were similar when CM was added 4 h after bacteria inoculation. There was no difference in somatic cell count between cases of acute mastitis in the CM-treated or control group in the in vivo study. However, relapses in chronic mastitis were less common in the group receiving CM. Our results show that CM is able to mitigate bacterial growth in vitro and may be particularly useful in the treatment of chronic mastitis, aiding restoration of milk production in cows that would otherwise be removed from the production cycle.

Different Culture Times Affect MicroRNA Cargo in Equine Amniotic Mesenchymal Cells and Their Microvesicles

Conditioned medium (CM) and microvesicles (MVs) are produced using different protocols: CM is collected following 12-96 h of cell culture without renewal of tissue culture medium, while MVs are collected after overnight cell culture. For future comparative studies in regenerative medicine looking at the efficacy of CM and MVs, it is important to understand how the quality of cell secretions is affected by culture. The aim of this study was to evaluate whether the duration of culturing influences the micro-RNAs (miRNAs) cargo of equine amniotic mesenchymal cells (AMCs) and their MVs. The analysis identified 990 miRNAs. After one night, there were 347 differently expressed (DE)-miRNAs between MVs and cells, whereas after four nights there were 359. About 58.3% of the DE-miRNAs were shared between samples produced under the two conditions. The comparison between miRNA content in AMC cells cultured for one night versus four nights showed eight DE-Equus caballus (eca)-miRNAs, which target genes were involved in immune response to external stimulus, inflammatory response, and production of reactive oxygen species. Comparing MVs isolated from one or four nights, four DE-miRNAs that target genes regulating cell cycle progression and production of reactive oxygen species were found, but only eca-miR-214 was enriched in the MVs after four nights. In conclusion, after 4 days of cell culture, the profile of AMC miRNAs was altered, indicating a probable phenotypic transition versus a new cell culture environment and aging. After this time, MVs accumulated eca-miR-214, which may help cells survive or adapt to new culture conditions.

Insights into animal models for cell-based therapies in translational studies of lung diseases: Is the horse with naturally occurring asthma the right choice?

Human asthma is a widespread disease associated with chronic inflammation of the airways, leading to loss of quality of life, disability and death. Corticosteroid administration is the mainstream treatment for asthmatic patients. Corticosteroids reduce airway obstruction and improve quality of life, although symptoms persist despite treatment in many patients. Moreover, available therapies failed to reverse the lung pathology present in asthma. Animal models, mostly rats and mice, in which the disease is experimentally induced, have been studied to identify new therapeutic targets for human asthma. Alternative animal models could include horses in which naturally occurring asthma could represent an important step to test therapies, potentially designed around mouse studies, before being translated to human testing. Horses naturally suffer from asthma, which has striking parallels with human asthma. Severe equine asthma (SEA) is characterized by reversible bronchospasms and neutrophil accumulation in the lungs immunologically mediated mainly by Th2. Moreover, the pulmonary remodelling that occurs in SEA closely resembles that of human asthma, making the equine model unique for investigation of tissue repair and new therapies. Cell therapy, consisting on mesenchymal stromal cells (MSCs) and derivatives (conditioned medium and extracellular vesicles), could represent a novel therapeutic contribution for tissue regeneration. Cell therapy may prove advantageous over conventional therapy in that it may repair or regenerate the site of injury and reduce the reaction to allergens, rather than simply modulating the inflammatory process.

MicroRNAs of Equine Amniotic Mesenchymal Cell-derived Microvesicles and Their Involvement in Anti-inflammatory Processes

Cell-derived microvesicles (MVs) are a recently discovered mechanism of cell-to-cell communication. Our previous data show that MVs secreted by equine amniotic mesenchymal-derived cells (AMCs) are involved in downregulation of proinflammatory genes in lipopolysaccharide-stressed equine tendon and endometrial cells. The aim of the present study was to evaluate whether AMC-MVs contain selected microRNAs (miRNAs) involved in inflammation. Two pools of cells, derived from 3 amniotic membranes each, and their respective MVs were collected. Small RNAs were extracted and deep sequenced, followed by miRNA in silico detection. The analysis identified 1,285 miRNAs, which were quantified both in AMCs and MVs. Among these miRNAs, 401 were classified as Equus caballus miRNAs, 257 were predicted by homology with other species (cow, sheep, and goat), and 627 were novel candidate miRNAs. Moreover, 146 miRNAs differentially expressed (DE) in AMCs and MVs were identified, 36 of which were known and the remaining were novel. Among the known DE miRNAs, 17 showed higher expression in MVs. Three of these were validated by real time polymerase chain reaction: eca-miR-26, eca-miR-146a, and eca-miR-223. Gene ontology analysis of validated targets showed that the DE miRNAs in cells and MVs could be involved both in immune system regulation by modulating interleukin signaling and in the inflammatory process. In conclusion, this study suggests a significant role of AMCs in modulating immune response through cell–cell communication via MV-shuttling miRNAs.

59 Effect of amniotic progenitor cell microvesicles on freezing of in vitro-produced bovine embryos and on pregnancy rate after embryo transfer

Microvesicles (MV) are involved in communication mechanisms based on microRNAs active in the regulation of gene decisive in biological processes such as gametogenesis, fertilization, implantation and embryo development. In this context, in our previous study (Perrini et al. 2018 Reprod. Fertil. Dev. 30, 658-671), amniotic derived MV, and to a lesser extent MV derived from endometrial cells, were effective on stimulating embryo development, demonstrating that MV-exposed embryos show a larger number of cells constituting the inner cell mass, greater viability, higher expression of GPX1 gene (protective against lipid peroxidation) and lower expression of BAX gene (involved in apoptosis) compared with the control. In this study, further effects of amniotic-derived MV on bovine embryo were evaluated. Bovine embryo survival rate after cryopreservation and on pregnancy rate after embryo transfer of fresh or cryopreserved MV-exposed embryos were studied. Embryos were produced from 3782 oocytes. Basing on our previously published protocol (Perrini et al. 2018 Reprod. Fertil. Dev. 30, 658-671), presumptive zygotes were randomly transferred in SOFaa (control, CTR) or cultured by adding 50×106 of amniotic-derived MV mL−1 in the SOFaa on Day 5 post-fertilization (Perrini et al. 2018 Reprod. Fertil. Dev. 30, 658-671). The embryo developmental rate was evaluated at Day 7 (blastocyst stage), and after that, part of the embryos were fresh transferred, whereas part of them were cryopreserved in 1.5 ethylene glycol using a standard slow freezing curve. One fresh or cryopreserved embryo was transferred in each recipient. Statistical analyses were performed by ANOVA with nonparametric Kruskal-Wallis test and for pregnancy rate by chi-square test. Differences were considered statistically significant at P &lt; 0.05. Results showed that blastocyst rate was 34.59±1.32% (709/2050) in CTR and 34.24±1.71% (593/1732) with MV. After cryopreservation, embryo survival was statistically different (P&lt;0.05) between CTR (32.71±6.26%; 87/266) and MV (43.09±5.73%; 78/181), respectively. The pregnancy rate was statistically different (P&lt;0.05) after embryo transfer of fresh embryos, with 66.67% (20/30 cows) of pregnancies for MV and 36.67% (11/30) for CTR. The transfer of cryopreserved embryos again provided a statistically (P&lt;0.05) different result: 36.67% (11/30) for MV embryos versus 10% (3/30) for CTR. These data show that the pregnancy rate of fresh or cryopreserved MV embryos is higher compared with CTR. Based on our previous data demonstrating higher expression of GPX1 gene and lower expression of BAX gene in presence of MV, these results indicate that the higher expression of the GPX1 gene probably limits the damage of lipid peroxidation by improving the survival rate following cryopreservation, whereas the less expressed BAX gene limits damages due to apoptosis. In conclusion, amniotic-derived MV probably play a biological role in the interaction between the embryo and the endometrium, providing a more resource-rich environment.

Oviductal microvesicles and their effect on in vitro maturation of canine oocytes

The effect of conditioned medium (CM) or microvesicles (MVs), secreted by multicellular spheroids of oviductal cells, and the involvement of some microRNAs (miRNAs) were investigated in canine oocyte maturation. To generate CM, spheroids were cultured for 3 days. MVs were obtained by ultracentrifugation of CM at 100,000 g and measured for size and concentration by NanoSight instrument. Cumulus-oocyte complexes (COCs) were matured at 38.5°C with 5% CO₂ and 5% of O₂ in synthetic oviductal fluid (SOF) in biphasic systems: for 24 h, with 5.0 μg/mL of LH and for other 48 h with 10% oestrous bitch serum. SOF was used as control (CTR) or supplemented with 10% CM or 25-50-75-100-150 × 10⁶ MVs/mL labeled with PKH-26. Results show that multicellular aggregates secreted shedding vesicles. By fluorescence microscopy, the incorporation of labeled MVs was visible only at 72 h in oocyte cytoplasm. These MVs had a positive effect (P < 0.05) on maturation rate (MII) at the concentration of 75 and 100 × 10⁶ MVs/mL compared to CM and CTR (20.34% and 21.82% vs 9.09% and 8.66% respectively). The concentration of 150 × 10⁶ MVs/mL provided only 9.26% of MII. The expression of three specific miRNAs (miR-30b, miR-375 and miR-503) was studied. The lower rate of MII with the higher concentration of MVs is possibly due to the high level of miR-375. In conclusion, the oviductal MVs could be involved in cellular trafficking during oocyte maturation and their possible use in vitro could facilitate the exploitment of canine reproductive biotechnologies.

190 Profile of MicroRNAs of Equine Amniotic Mesenchymal Cell-Derived Microvesicles in Different Time-Span of In Vitro Culture

Mesenchymal stromal cells (MSC) were found to secrete many factors with therapeutic relevance for their antioxidants, antiapoptotic, antifibrotic, angiogenic, immunomodulatory, and chemiotactic activities. The culture supernatant of MSC (in our case, of equine amniotic-derived cells) is defined secretome or conditioned medium (CM) and it is composed of soluble and insoluble factors secreted by cells. Soluble factors are represented by cytokines and growth factors, whereas microvesicles (MV), recently demonstrated to be an integral component of cell-to-cell communication during tissue regeneration, represent insoluble factors (Bruno et al. 2009 J. Am. Soc. Nephrol. 20, 1053-1067). Our previous data showed that equine amniotic-derived CM administered in vivo in equine spontaneous tendon lesion is able to regenerate the injured tissue. overlapping the results obtained by using in vivo the cells of origin in the same pathology (Lange-Consiglio et al. 2013 Stem Cells Devel. 22, 3015-3024). We also studied the amniotic-derived MV and found that they are involved in down-regulation of pro-inflammatory genes in in vitro LPS-stressed equine tendon and endometrial cells (Lange-Consiglio et al. 2016 Stem Cells Devel. 25, 610-621; Perrini et al. 2016 Stem Cell Res. Ther. 7, 169). Usually, protocols to produce CM and MV are different: CM is collected after 48 to 96 h of culturing cells without renewal of tissue culture medium, whereas MV are collected after culturing cells overnight. In future comparative studies of regenerative medicine aiming to understand the efficacy of CM and MV, understanding the quality of secretion of cells according to culturing time is crucial. The aim of the present study was to evaluate whether different times of culture can influence the micro-RNA (miRNA) cargo of equine amniotic-derived cells and their MV. Biological triplicates of a pool of amniotic-derived cells from 2 amniotic membranes and their MV, collected after overnight or after 4 days, were used. Following miRNA extraction and library preparation, deep sequencing was carried out on Illumina HisSEqn 2000 (Illumina Inc., San Diego, CA, USA). Mirdeep2 on Illumina high-quality trimmed sequences was used to detect known miRNAs and to support the individuation of novel miRNAs. The analysis identified 335 Equus caballus miRNA, which were quantified in both amniotic cells and MV. Hierarchical clustering of 83 miRNA that were observed in all 12 samples clearly discriminated amniotic cells and MV. The profile of miRNA in AMC and MV was similar between overnight and 4 days of culture. Further functional studies on the predicted target genes and pathways involved in the biological effect of equine amniotic secretome will be performed.

149 Preliminary Results of the Oxytocin Treatment on the Collection of Cat Semen by Urethral Catheterization After Pharmacological Induction

Urethral catheterization after pharmacological induction (Ur.Ca.P.I.) has been developed as a method to collect semen from cats (Zambelli et al. 2008 Theriogenology 69, 485-490). This procedure is based on contraction of the vas deferens induced by the α-agonist medetomidine and the subsequent release of sperm into the urethra. To ensure adequate sedation, the medetomidine dosage is 130 µg kg−1. Usually, a single collection of semen is done by catheterization immediately after medetomidine takes effect. A 3.5 French (Fr) gauge urinary tom cat catheter with the tip cut is inserted 90 mm deep into the urethra. Even in the absence of clinical signs, the cut catheter tip may cause minor trauma to the urethral mucosa. Aims of this study were to test a new catheter and evaluate effects of oxytocin administration on quality and quantity of semen collected. The study was performed on 8 client-owned, pubertal domestic cats, 10 to 18 months old. These cats were randomly allocated into 2 groups: control and treatment, with 3 and 5 cats, respectively. In each group, 2 semen collections were performed. The catheter had a diameter of 4 Fr and a rounded tip without mandrel and it was inserted 90 mm deep. In both groups, the first collection was performed as effects of medetomidine were apparent. In the control group, the second collection was done 10 min later. However, in the treated group, 5 IU of oxytocin was injected intramuscularly immediately after semen collection, with the second collection performed 10 min later. Semen was evaluated for volume, concentration, rate of progressive motility, curvilinear speed (VCL), morphology, and vitality. Comparisons between collections and between groups were done with a Student’s t-test. Comparing the second versus first collection in the control group, there was only an increase in volume (9.33 v. 2.67 µL; P < 0.05). In contrast, in the oxytocin group, all parameters evaluated were better (P < 0.05) for the second collection. As expected, the first collection was not different between the 2 groups for any parameter. However, for the second collection, there were differences (P < 0.05) between the oxytocin and the control group for volume (12.6 v. 3.7 µL), concentration (1252.6 v. 858 × 106 sperm mL−1), progressive motility (90.2 v. 77.8%), VCL (137.71 v. 117.94 µm s−1), morphologically normal sperm (87.0 v. 81.4%), and vitality (86.4 v. 82.8%). Oxytocin may be involved in mobilization of sperm from the epididymis. We concluded that oxytocin improved recovery of sperm from epididymal reserves, resulting in sperm with better morphology and function than those present in the vas deferens.

188 IMPROVEMENT OF IN VITRO CANINE OOCYTE MATURATION BY OVIDUCTAL SECRETOME

The in vitro maturation of canine oocyte is problematic because it is difficult to reproduce the oviducal microenvironment where the in vivo maturation occurs. Because cells are able to communicate with each other by paracrine action, oviducal cells could be in vitro cultivated to obtain the conditioned medium (CM) consisting of soluble factors and microvesicles (MV), which represent a carrier for nonsoluble molecules including microRNA. The aim of the present work was to investigate the effect of the addition of CM or MV, secreted by oviducal cells, to the canine in vitro maturation medium. To generate CM, cells from oviducts of 3 animals in late oestrus were cultured for 5 days at 38.5°C in a humidified atmosphere of 5% CO2. Supernatants were collected, pooled, centrifuged at 2500 × g, and stored at −80°C. Microvesicles were obtained by ultracentrifugation of CM at 100,000 × g for 1 h at 4°C and measured for concentration and size by a Nanosight instrument. Ovaries were obtained from 50 healthy domestic bitches (1–4 years old) of different breeds that underwent ovariectomy regardless of the oestrous cycle. Cumulus-oocyte complexes were released by slicing the ovarian cortex with a scalpel blade, and only Grade 1 cumulus-oocyte complexes (darkly granulated cytoplasm and surrounded by 3 or more compact cumulus cell layers) 110 to 120 µm in diameter were selected for culture. Maturation was performed at 38.5°C in a humidified atmosphere of 5% CO2 and 5% of O2 in bi-phasic systems: 24 h in SOF with 5.0 μg mL−1 of LH followed by 48 h in SOF supplemented with 10% of oestrous bitch serum and 10% CM or 50, 75, 100, or 150 × 106 MV mL−1 labelled with PKH-26. Control was the same medium without CM or MV. Oocytes were observed under a fluorescent microscope to detect metaphase II (MII), by Hoechst staining, and the incorporation of MV. Statistical analysis was performed by chi-square test. Results show that canine oviducal cells secreted MV of 234 ± 23 nm in size, underling that these MV fall within the shedding vesicles category. The incorporation of labelled MV occurred at first in cumulus cells, at 48 h of maturation, and then, at 72 h, in oocyte cytoplasm. These MV had a positive effect on maturation rate (MII) at the concentration of 75 and 100 × 106 MV mL−1 compared with CM and control (20.34 and 21.82 v. 9.09 and 3.95%, respectively). The concentration of 150 × 106 MV mL−1 provided only 9.26% of MII. To understand the role of MV, we assessed the expression of 3 microRNA (miRNA-30b, miR-375, and miR-503) that are involved in some key pathways (WNT, MAPK, ERbB, and TGFβ) regulating follicular development and meiotic resumption. The lower rate of MII with the higher concentration of MV is possibly due to the high level of miR-375, which recent literature shows to suppress the TGFβ pathway, leading to impaired oocyte maturation. In conclusion, the oviducal MV, or specific microRNA, are involved in cellular trafficking during oocyte maturation, and their possible use in vitro could facilitate the exploitation of canine reproductive biotechnologies.

Microvesicles secreted from equine amniotic-derived cells and their potential role in reducing inflammation in endometrial cells in an in-vitro model

Background

It is known that a paracrine mechanism exists between mesenchymal stem cells and target cells. This process may involve microvesicles (MVs) as an integral component of cell-to-cell communication.

Methods

In this context, this study aims to understand the efficacy of MVs in in-vitro endometrial stressed cells in view of potential healing in in-vivo studies. For this purpose, the presence and type of MVs secreted by amniotic mesenchymal stem cells (AMCs) were investigated and the response of endometrial cells to MVs was studied using a dose-response curve at different concentrations and times. Moreover, the ability of MVs to counteract the in vitro stress in endometrial cells induced by lipopolysaccharide was studied by measuring the rate of apoptosis and cell proliferation, the expression of some pro-inflammatory genes such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin 1β (IL-1β), and metalloproteinases (MMP) 1 and 13, and the release of some pro- or anti-inflammatory cytokines.

Results

MVs secreted by the AMCs ranged in size from 100 to 200 nm. The incorporation of MVs was gradual over time and peaked at 72 h. MVs reduced the apoptosis rate, increased cell proliferation values, downregulated pro-inflammatory gene expression, and decreased the secretion of pro-inflammatory cytokines.

Conclusion

Our data suggest that some microRNAs could contribute to counteracting in-vivo inflammation of endometrial tissue.

Isolation, molecular characterization, and in vitro differentiation of bovine Wharton jelly-derived multipotent mesenchymal cells

Extrafetal tissues are a noncontroversial and inexhaustible source of mesenchymal stem cells that can be harvested noninvasively at low cost. In the veterinary field, as in man, stem cells derived from extrafetal tissues express plasticity, reduced immunogenicity, and have high anti-inflammatory potential making them promising candidates for treatment of many diseases. Umbilical cord mesenchymal cells have been isolated and characterized in different species and have recently been investigated as potential candidates in regenerative medicine. In this study, cells derived from bovine Wharton jelly (WJ) were isolated for the first time by enzymatic methods, frozen/thawed, cultivated for at least 10 passages, and characterized. Wharton jelly-derived cells readily attached to plastic culture dishes displaying typical fibroblast-like morphology and, although their proliferative capacity decreased to the seventh passage, these cells showed a mean doubling time of 34.55 ± 6.33 hours and a mean frequency of one colony-forming unit fibroblast like for every 221.68 plated cells. The results of molecular biology studies and flow cytometry analyses revealed that WJ-derived cells showed the typical antigen profile of mesenchymal stem cells and were positive for CD29, CD44, CD105, CD166, Oct-4, and c-Myc. They were negative for CD34 and CD14. Remarkably, WJ-derived cells showed differentiation ability. After culture in induced media, WJ-derived cells were able to differentiate into osteogenic, adipogenic, chondrogenic, and neurogenic lines as shown by positive staining and expression of specific markers. On polymerase chain reaction analysis, these cells were negative for MHC-II and positive for MHC-I, thus reinforcing the role of extrafetal tissue as an allogenic source for bovine cell-based therapies. These results provide evidence that bovine WJ-derived cells may have the potential to differentiate to repair damaged tissues and reinforce the importance of extrafetal tissues as stem cell sources in veterinary regenerative medicine. A more detailed evaluation of their immunologic properties is necessary to better understand their potential role in cellular therapy.

Evaluation of amniotic mesenchymal cell derivatives on cytokine production in equine alveolar macrophages: an in vitro approach to lung inflammation

Background

Data obtained in both animal models and clinical trials suggest that cell-based therapies represent a potential therapeutic strategy for lung repair and remodeling. Recently, new therapeutic approaches based on the use of stem cell derivatives (e.g., conditioned medium (CM) and microvesicles (MVs)) to regenerate tissues and improve their functions were proposed. The aim of this study was to investigate the immunomodulatory effects of equine amniotic mesenchymal cell derivatives on lipopolysaccharide (LPS)-induced cytokine production in equine alveolar macrophages, which may be beneficial in lung inflammatory disorders such as recurrent airway obstruction (RAO) in horses. RAO shares many features with human asthma, including an increased number of cells expressing mRNA for interleukin (IL)-4 and IL-5 and a decreased expression of IFN-γ in bronchoalveolar lavage fluid (BALF) of affected horses.

Methods

The release of TNF-α, IL-6, and TGF-β1 at different time points (1, 24, 48, and 72 h) was measured in equine alveolar macrophages stimulated or not with LPS (10 and 100 ng/mL) in the presence or absence of 10 % CM or 50 × 10⁶ MVs/mL.

Cytokines were measured using commercially available ELISA kits. For multiple comparisons, analysis of variance was used with Tukey post-hoc test. Differences were considered significant at p ≤ 0.05.

Results

Significant modulatory effects of CM on LPS-induced TNF-α release at 24 h, and of both CM and MVs on TNF-α release at 48 h were observed. A trend toward a modulatory effect of both CM and MVs on the release of TGF-β and possibly IL-6 was visible over time.

Conclusions

Results support the potential use of CM and MVs in lung regenerative medicine, especially in situations in which TGF-β may be detrimental, such as respiratory allergy. Further studies should evaluate the potential clinical applications of CM and MVs in equine lung diseases, such as RAO and other inflammatory disorders.

Effects of platelet-rich plasma in a model of bovine endometrial inflammation in vitro

BACKGROUND

Endometritis reduces fertility and is responsible for major economic losses in beef and dairy industries. The aim of this study was to evaluate an alternative therapy using platelet-rich plasma (PRP). PRP was tested in vivo, after bovine intrauterine administration, and in vitro on endometrial cells.

METHODS

Bovine endometrial cells were cultured until passage (P) 10 with 5 % or 10 % PRP. Effect of PRP on endometrial cell proliferation and on the expression of genes [prostaglandin-endoperoxide synthase 2 (COX2), tumor protein p53 (TP53), oestrogen receptors (ER-α and ER-β), progesterone receptor (PR) and c-Myc] involved in the regulation of oestrus cycle and fetal-maternal interaction were evaluated. Moreover, to evaluate the ability of PRP to counteract inflammation, 10 and 100 ng/ml of bacterial endotoxin lipopolysaccharide (LPS) were used to inflame endometrial cells in vitro for 1, 6, 12, 24 and 48 h. The expression of genes such as interleukin 1β (IL-1β), interleukin-8 (IL-8), inducible nitric oxide synthase (iNOS), prostaglandin-endoperoxide synthase 2 (COX2/PTGS2), and the release of PGE-2, IL-1β and IL-8 were evaluated.

RESULTS

In vivo treatment with PRP increased the detection of PR. In vitro, 5 % PRP at passage 5 increased proliferation rate and induced a significant increase in the expression of all studied genes. Furthermore, the results revealed that 10 ng/ml of LPS is the most effective dose to obtain an inflammatory response, and that PRP treatment significantly down regulated the expression of pro-inflammatory genes.

CONCLUSION

This study lays the foundations for the potential treatment of endometritis with PRP in vivo.

Does the Bovine Pre-Ovulatory Follicle Harbor Progenitor Stem Cells?

Recent studies have revealed the presence of a mesenchymal stem cell (MSC) population in human and in gilt granulosa cells (GCs), thus increasing the interest in identifying the same population in the bovine species. We first isolated GCs by scraping from bovine preovulatory follicles and then tested several different media to define the ideal conditions to select granulosa-derived stem cells. Although expressing MSC-associated markers, none of the media tested proven to be efficient in selecting MSC-like cells that were able to differentiate into mesodermic or ectodermic lineages. We performed another experimental approach exposing cells to a chemical stress, such as lowering of pH, as a system to select a more plastic population. Following the treatment, granulosa-specific granulose markers [follicle-stimulating hormone receptor (FSHR), follistatin (FST), and leukemia inhibitory factor receptor (LIFR)] were lost in bovine GCs, whereas an increase in multi- (CD29, CD44, CD73) and pluripotent (Oct-4 and c-Myc) genes was noticed. The stress allowed up-regulation of tumor necrosis factor-α and interleukin-1β expression and the dedifferentiation of GCs, which was demonstrated by differentiation studies. Indeed, pH-treated cells were able to differentiate into the mesodermic and ectodermic lineages, thus suggesting that the chemical stress allows for the selection of cells that are more prone to adjust and respond to the environmental changes.

226 EFFECTS OF MICROVESICLES SECRETED FROM EQUINE AMNIOTIC-DERIVED PROGENITOR CELLS ON IN VITRO LIPOPOLYSACCHARIDE-TREATED TENDON AND ENDOMETRIAL CELLS

Administration of horse amniotic mesenchymal cell conditioned medium (AMC-CM) improves the in vivo recovery of spontaneous equine tendon lesions. This effect may involve paracrine mechanisms whose nature remains unknown. It has recently been demonstrated that microvesicles (MV) released from cells are an integral component of cell-to-cell communication during tissue regeneration. Aims of this study were to investigate the presence and type of MV secreted by AMC using Nanosight instrument (Malvern Instruments, Malvern, UK) and transmission electron microscopy (TEM) and the incorporation of MV in equine tendon and endometrial cells by fluorescence semiquantitative analysis. Tendon cells were used to understand the in vitro role of MV on stressed cells compared with the in vivo results previously obtained, while the endometrial cells were investigated in view of the prospective use of AMC-CM or MV in in vivo inflammatory endometrial diseases. Moreover, the ability of MV to counteract in vitro inflammation of tendon and endometrial cells induced by lipopolysaccharide (LPS) was also evaluated. The MV were obtained by ultracentrifugation at 100 000 × g for 1 h at 4°C of the media obtained by culturing AMC isolated from 3 different placentas. Tendon and endometrial cells were obtained from collagenase digestion for 17 and 3 h, respectively and cultured in HG-DMEM with 10% fetal calf serum. To study the ability of tendon and endometrial cells to incorporate MV, a dose-response curve was performed adding 10, 20, 30, 40, and 50 × 106 MV mL–1 labelled with PKH-26 for 24, 48, and 72 h. The uptake of MV was evaluated by an Olympus BX51 microscope (Olympus, Tokyo, Japan) equipped with software for image acquisition. A dose-response curve of LPS was also investigated by apoptotic and MTT tests showing that 100 ng mL–1 at 48 h on tendon cells and 10 ng at 24 h on endometrial cells were the doses and times most effective in inducing cellular stress. RT-qPCR expression of pro-inflammatory genes such as metallopeptidase (MMP) 1 and 13 was evaluated in the in vitro LPS stress by Mann-Whitney U-test. Results by Nanosight Instrument showed that AMC secrete MV in the range of 100 to 200 nm; TEM showed budding of the AMC membrane, proving that these MV fall within the shedding vesicles category. The same semiquantitative fluorescence uptake signal was obtained when 50 × 106 MV were incorporated at 24 h, or 40 × 106 MV at 48 h, and 30 × 106 MV at 72 h, suggesting that an inverse correlation between concentration and time was found in MV uptake equally by tendon and endometrial cells. The MV induced a significant (P < 0.05) down-regulation of MMP1 and MMP13 expression in both cell lines after in vitro LPS stress. Our data suggest that these MV can be incorporated in tendon and endometrial cells and have a role in modulating inflammatory genes in vitro.

Leptin and leptin receptor are detectable in equine spermatozoa but are not involved in in vitro fertilisation

In human and swine, leptin (OB) has been identified in seminal plasma and leptin receptors (OB-R) on the cell surface of spermatozoa, indicating that spermatozoa are a target for OB. This hormone has also been detected in follicular fluid (FF) in women and mares, although its role requires further study. The aims of this study were to investigate the immunolocalisation and the expression of OB and OB-R in equine spermatozoa and to evaluate the involvement of OB in equine in vitro fertilisation (IVF). Since progesterone (P) and OB are both found in FF, the individual and combined effects of these two hormones were studied in equine IVF and compared with the results obtained from the use of FF for in vitro sperm preparation. For the first time, we were able to identify OB and OB-R mRNA and their corresponding proteins in equine spermatozoa. When spermatozoa were treated with OB, there was a decrease in the three motility parameters VSL, STR and LIN, commonly associated with hyperactivation, whilst the acrosome reaction rate increased (P < 0.05). The fertilisation rate was 51% with FF, 46.15% with P, 43.64% with P+OB and 0% with OB alone. The percentage of eight-cell stage embryos was 18.7% with FF, 17.1% with P and 16.7% with OB+P. OB alone did not permit oocyte fertilisation, indicating that, in the horse, OB is involved in capacitation and hyperactivation but not in sperm penetration.

Peculiarity of Porcine Amniotic Membrane and Its Derived Cells: A Contribution to the Study of Cell Therapy from a Large Animal Model

The aim of this work was to provide, for the first time, a protocol for isolation and characterization of stem cells from porcine amniotic membrane in view of their potential uses in regenerative medicine. From three samples of allanto-amnion recovered at delivery, the amniotic membrane was stripped from overlying allantois and digested with trypsin and collagenase to isolate epithelial (amniotic epithelial cells [AECs]) and mesenchymal cells, respectively. Proliferation, differentiation, and characterization studies by molecular biology and flow cytometry were performed. Histological examination revealed very few mesenchymal cells in the stromal layer, and a cellular yield of AECs of 10 × 10(6)/gram of digested tissue was achieved. AECs readily attached to plastic culture dishes displaying typical cuboidal morphology and, although their proliferative capacity decreased to the fifth passage, AECs showed a mean doubling time of 24.77 ± 6 h and a mean frequency of one fibroblast colony-forming unit (CFU-F) for every 116.75 plated cells. AECs expressed mesenchymal stem cell (MSC) mRNA markers (CD29, CD166, CD90, CD73, CD117) and pluripotent markers (Nanog and Oct 4), whereas they were negative for CD34 and MHCII. Mesodermic, ectodermic, and endodermic differentiation was confirmed by staining and expression of specific markers. We conclude that porcine amniotic membrane can provide an attractive source of stem cells that may be a useful tool for biomedical research.

Cell Surface Glycan Changes in the Spontaneous Epithelial-Mesenchymal Transition of Equine Amniotic Multipotent Progenitor Cells

Amniotic epithelial cells (AECs) spontaneously transform into amniotic mesenchymal cells (AMCs) in vitro during cell culture. Glycocalyx was analyzed to identify the glycan pattern in AECs, AMCs and epithelial-mesenchymal transdifferentiated cells (EMTCs). Pure cell cultures were derived using cloned AEC and AMC cell lines obtained by the dilution technique from amniotic membranes. Mesenchymal cells generated by differentiation of clonal epithelial cells were considered transdifferentiated. Immunocytoscreen, in vitro multipotent differentiation and molecular characterization of EMTCs were performed. In combination with saponification and sialidase digestion, a panel of 12 lectins was used to analyze the glycan pattern of AEC, AMC and EMTC glycocalyx. Cytokeratin cell markers were lost in EMTCs and typical mesenchymal markers, such as vimentin, appeared. These cells retained their differentiation potential. Lectin histochemistry revealed a cell-specific glycan profile. Galactose (Gal)β1,4GlcNAc, Neu5Acα2,6Gal/GalNAc and N-acetyl neuraminic (sialic) acid (NeuNAc)α2,3Galβ1,3(±NeuNAcα2,6)GalNAc were highly expressed on the surface of all the amniotic cell cultures. AECs expressed asialoglycans with terminal GalNAc and GlcNAc. More highly mannosylated N-linked glycans and NeuNAcα2,3Galβ1,3GalNAc in O-linked glycans were expressed by EMTCs, but these cells had fewer glycans ending with fucose (Fuc), Gal, GlcNAc and GalNAc than AECs. GlcNAc- and GalNAc-terminating glycans were similarly expressed on the glycocalyx of the mesenchymal cell populations (EMTCs and AMCs). These results demonstrate for the first time that the spontaneous epithelial-mesenchymal transition (EMT) of equine amnion cells is characterized by cell surface glycan remodeling and that glycosylation changes result in a cell type-specific glycan profile. The glycopattern of equine amnion spontaneous EMTCs differs from EMT of tumoral cells.

Platelet concentrate in bovine reproduction: effects on in vitro embryo production and after intrauterine administration in repeat breeder cows

BACKGROUND

A repeat breeder cow (RBC) can be defined as an animal that after 3 or more inseminations cannot get pregnant because of fertilization failure or early embryonic death. If no cause is identified precisely, inadequate uterine receptivity is responsible for implantation failures. Since a large number of identified molecular mediators, such as cytokines, growth factors and lipids have been postulated to be involved in early feto-maternal interaction, in this study a different approach to the treatment of RBC syndrome has been employed using a platelet concentrate (PC) that contains a significant amount of growth factors accumulated in its α-granules.

METHODS

Three explorative studies were performed. Initially, PC was supplemented in the in vitro embryo culture medium to study its effect on embryo-development. After the pilot study, 4 RBCs were treated with intrauterine administration of PC to evaluate proliferative potential of endometrium by immunohistochemical expression of the antigen Ki-67. Lastly, the effect of intrauterine administration of PC at 48 hrs after artificial insemination in RBCs was evaluated.

RESULTS

The in vitro results show that 5 % of PC and 5 % of fetal calf serum (FCS) increase the rate of blastocysts compared with the control containing 10 % FCS only (43.04 % vs 35.00 % respectively). The immunohistochemical study shows more proliferating nuclei in the treated uterine horn compared to the control one. After intrauterine insemination in RBCs, the percentage of pregnant cows in the control group was 33.33 % compared to 70 % of the treated animals.

CONCLUSION

We suppose that when embryo descends in uterus could find a more appropriate environment for nesting and subsequent pregnancy.

327 PORCINE AMNION: A SOURCE OF EPITHELIAL STEM CELLS

The use of pig models for preclinical testing is well established, and the availability of stem cells from this species would open the way to preclinical studies for application of cell therapy. According to the developmental stage from which they are obtained, stem cells are classified as being embryonic, fetal, or adult. Embryonic stem cells have unlimited self-renewing capacity and multilineage differentiation potential, but their clinical application seems to be hindered by the high tumorigenic rate after transplantation. Mesenchymal stem cells (MSC) derived from adult tissues are considered to be more limited in their potential and the risk of the immunological rejection of the transplanted stem cells by the recipient is an important limiting factor. The MSC derived from extra-fetal tissues could overcome many of these restrictions. Indeed, in veterinary medicine, MSC isolated from equine term placenta were the ideal candidates for tendon disease treatment, specifically for their plasticity and their reduced immunogenicity compared to bone marrow-derived cells. Extra-fetal derived MSC in porcine have been isolated from the umbilical cord matrix and amniotic fluid. The aim of this work was to provide, for the first time, an isolation protocol and the characterisation of stem cells from porcine amniotic membrane, which could hold potential uses in regenerative medicine. The amnion is a thin, avascular membrane made of an epithelial layer and an outer layer of connective tissue. From 3 samples of allanto-amnion retrieved at delivery, each amniotic membrane was stripped from the overlying allantois and, for isolation of the epithelial cells, it was digested with trypsin. After removal of epithelial cells, the stromal layer was digested with collagenase to obtain amniotic mesenchymal cells. The cellular yield from term amnion resulted only in epithelial cells (AEC) at a concentration of 10 × 106 for 1 g of digested tissue while no MSC were obtained. Histology, indeed, revealed very few cells in the stromal layer. The AEC readily attached to plastic culture dishes. Culture was established in DMEM-HG medium, supplemented with 10% serum and 10 ng mL–1 of EGF where the cells proliferated robustly. The AEC displayed typical cuboidal morphology. These cells showed a mean of 31 ± 0.24 cell population doublings after 31 days. The mean frequency of colony-forming unit fibroblasts was 1 for each of the 75 plated cells. The AEC expressed MSC mRNA markers (CD29, CD166, CD90, CD73, CD117) and pluripotent markers (Nanog and Oct4), while were negative for CD34 and MHC-II. Osteogenic, adipogenic, and neurogenic differentiations were confirmed by von Kossa, Red Oil, and Nissle stains, respectively, and by expression of specific markers (osteocalcin and osteopontin for osteogenic differentiation, adiponectin and leptin for adipogenic differentiation, and glial fibrillary acid protein and nestin for neurogenic differentiation). We conclude that porcine amnion contain unique and primitive cells whose potential is as yet undefined. Ease of collection and propagation of AEC make this tissue an attractive candidate as a resource for stem cell biotechnology and biomedical research.

Intramammary administration of platelet concentrate as an unconventional therapy in bovine mastitis: first clinical application

Bovine udder infections induce a variety of changes in gene expression of different growth factors that may suggest their possible role in glandular tissue protection or repair processes. Growth factors and also chemokines and cytokines may act synergistically to increase the infiltration of neutrophils and macrophages to promote angiogenesis, fibroplasia, matrix deposition, and, ultimately, re-epithelialization. Considering the vast applications, typically in human medicine, of platelet concentrate (PC) and its ease of preparation, the aim of our study was to evaluate an alternative therapy to stimulate the regeneration of glandular tissue, administering a concentration in excess of the growth factors contained in the PC. In each one of the 3 farms examined in the trial, PC was prepared from donor cows in good health, free from infections, and with no records of medications administered during the previous 2 mo. The platelet produced in one farm was used only for treating the cows of the same farm in a heterologous way. A total of 229 mastitic quarters were divided in 3 groups: antibiotic group (treated with intramammary antibiotic), antibiotic and PC group (treated intramammarily with antibiotics in association with PC), and PC group (treated with intramammary PC alone). The diagnosis of mastitis was based on somatic cell count and bacteriological evaluation of the milk from the affected quarter. Platelet concentrate, alone or in association with antibiotic, was used for 3 consecutive days as an unconventional therapy in bovine acute and chronic mastitis. Our data show that the associated action of antibiotic and PC performed significantly better than the antibiotic alone, either for the recovery of the affected mammary quarters or for somatic cell count reduction. In the same way, the association antibiotic plus PC showed significantly fewer relapses compared with the antibiotic alone, either for acute or chronic mastitis. The treatment with only PC did not show statistically significant differences compared with both antibiotic alone or associated treatment for acute mastitis, and it was better than the use of only antibiotic for chronic mastitis. Our results show that PC alone may be useful for a quick resolution of the inflammatory response, playing a role in limiting the tissue damage to the mammary gland parenchyma and reducing the recurrence rates.

Follicular fluid leptin concentrations and expression of leptin and leptin receptor in the equine ovary and in vitro-matured oocyte with reference to pubertal development and breeds

There is no published information about follicular-fluid leptin concentrations or the presence of leptin and leptin receptor in the equine ovary or oocyte. Three groups of mares - adult draft mares, draft fillies and adult Standardbred mares - were included in the study. Leptin and leptin receptor were detected in all immature oocytes by immunofluorescence with higher intensity in oocytes from draft mares compared with draft fillies and Standardbred mares. After in vitro maturation a higher proportion of oocytes reached metaphase II in draft mares than in draft fillies and Standardbred mares, and in all groups both leptin and leptin receptor became localised in the oocyte cortex but with higher immunopositivity in draft mares compared with draft fillies and Standardbred mares. These intensities were confirmed by the expression profiles of leptin and leptin receptor mRNA. Moreover, leptin was detected in ovarian blood vessels in all three types of animal and within the corpora lutea in adult mares. Serum and follicular-fluid concentrations of leptin were similar in draft and Standardbred mares but higher in draft mares than in draft fillies. This study supports the hypothesis that expression of leptin and leptin receptor mRNA and the rate of maturation can be related either to adiposity or to puberty.

196 EPITHELIAL–MESENCHYMAL TRANSITION IN EQUINE AMNIOTIC PROGENITOR CELLS INDUCES CHANGES OF THE CELL GLYCAN PROFILE

Epithelial to mesenchymal transition (EMT) is the process by which epithelial cells dramatically alter their shape and motile behaviour as they differentiate into mesenchymal cells. The EMT and the reverse process, termed mesenchymal–epithelial transition, play central roles in embryogenesis. Gastrulation and neural crest formation are processes governed by EMT in amniotes. It is noteworthy that in placental mammals, the epithelial layer of amnion originates from the trophectoderm and it is continuous with the epiblast. On this basis, it is reasonable to speculate that some amniotic epithelial cells may escape the specification that accompanies gastrulation, and may retain some of the characteristics of epiblastic cells, such as pluripotency, behaving as stem cells that are able to preserve intrinsically the ability to transdifferentiate. Because it seems that malignant cells use the same mechanisms during the formation of tumours in vivo, the amniotic epithelial cells (AEC) could represent a good model to study in vitro this phenomenon that we observed to occur spontaneously in our culture conditions. The aim of this study was to characterise the glycoprotein pattern expressed in fresh or cryopreserved equine AEC, mesenchymal (AMC), and transdifferentiated cells by means of lectin histochemistry. AEC and AMC were cultured until passage (P) 3, while transdifferentiated cells at P1(EMT1) and P2 (EMT2). All cell lines were frozen for 1 month at –196°C in liquid nitrogen. The glycoanalysis was performed with a panel of twelve lectins to detect the glycans terminating with sialic acids (MAL II, SNA, PNA after sialidase digestion (K-s), K-s-DBA), galactose (PNA, RCA120, GSA I-B4,), N-acetylgalactosamine (DBA, HPA, SBA), N-acetylglucosamine (GSA II), fucose (UEA I, LTA), or with internal mannose (Con A). After freezing: 1) AEC exhibited decrease of binding sites for DBA, SBA, HPA, GSA II, and disappearance of GSA I-B4 and UEA I binders; 2) AMC displayed increase of SBA reactivity, decrease of K-s-PNA, HPA, GSA II staining, and absence of GSA I-B4 affinity; 3) EMT1 cells showed the appearance of K-s-DBA staining, the increase of K-s-PNA, RCA120, SBA, GSA I-B4, and UEA I reactivity, the decrease of MAL II, SNA, HPA, GSA II binders, and the disappearance of DBA and LTA binding sites; 4) EMT2 cells revealed the increase of K-s-PNA, GSA I-B4, UEA I affinity, the decrease of MAL II, SNA, RCA120, HPA, GSA II binders, and the lack of DBA, SBA, and LTA reactivity. In conclusion, this study demonstrates that the EMT induces changes in cell surface glycan profile of equine amniotic progenitor cells, and for the first time revealed that freezing modifies the lectin binding pattern of these cells. The observed glycan pattern modification may represent one aspect of the spontaneous complex process of EMT.

Molecular characterization and in vitro differentiation of feline progenitor-like amniotic epithelial cells

Introduction

While amniotic mesenchymal cells have been isolated and characterized in different species, amniotic epithelial cells (AECs) have been found only in humans and horses and are recently considered valid candidates in regenerative medicine. The aim of this work is to obtain and characterize, for the first time in the feline species, presumptive stem cells from the epithelial portion of the amnion (AECs) to be used for clinical applications.

Methods

In our study, we molecularly characterized and induced in vitro differentiation of feline AECs, obtained after enzymatic digestion of amnion.

Results

AECs displayed a polygonal morphology and the mean doubling time value was 1.94 ± 0.04 days demonstrating the high proliferating capacity of these cells. By RT-PCR, AECs expressed pluripotent (Oct4, Nanog) and some mesenchymal markers (CD166, CD44) suggesting that an epithelial-mesenchymal transition may occur in these cells that lack the hematopoietic marker CD34. Cells also showed the expression of embryonic marker SSEA-4, but not SSEA-3, as demonstrated by immunocytochemistry and flow cytometry. Moreover, the possibility to use feline AECs in cell therapies resides in their low immunogenicity, due to the absence of MHC-II antigen expression. After induction, AECs differentiated into the mesodermic and ectodermic lineages, demonstrating high plasticity.

Conclusions

In conclusion, feline AECs appear to be a readily obtainable, highly proliferative, multipotent and non-immunogenic cell line from a source that may represent a good model system for stem cell biology and be useful in allogenic cell-based therapies in order to treat tissue lesions, especially with loss of substance.

Conditioned medium from horse amniotic membrane-derived multipotent progenitor cells: immunomodulatory activity in vitro and first clinical application in tendon and ligament injuries in vivo

We have recently demonstrated that heterologous transplantation of horse amniotic membrane-derived mesenchymal cells (AMCs) can be useful for cell therapy applications in tendon diseases, and hypothesized that these cells may promote tendon repair via paracrine-acting molecules targeting inflammatory processes. To test this hypothesis, here we examined the immunomodulatory characteristics of AMCs and of their conditioned medium (AMC-CM) in vitro, and studied the potential therapeutic effect of AMC-CM in thirteen different spontaneous horse tendon and ligament injuries in vivo. Our results demonstrate that AMCs are capable of inhibiting peripheral blood mononuclear cell (PBMC) proliferation after allogenic stimulation either when cocultured in cell-to-cell contact, or when the two cell types are physically separated by a transwell membrane, suggesting that soluble factors are implicated in this phenomenon. Our hypothesis is further supported by the demonstration that PBMC proliferation is inhibited by AMC-CM. In our in vivo studies, no significant adverse effects were observed in treated tendons, and clinical and ultrasonographical evaluation did not reveal evidence of inappropriate tissue or tumor formation. Clinical outcomes were favorable and the significantly lower rate (15.38%) of reinjuries observed compared to untreated animals, suggests that treatment with AMC-CM is very efficacious. In conclusion, this study identifies AMC-CM as a novel therapeutic biological cell-free product for treating horse tendon and ligament diseases.

Investigating the efficacy of amnion-derived compared with bone marrow-derived mesenchymal stromal cells in equine tendon and ligament injuries

BACKGROUND AIMS

This is the first study to compare the treatment of horse tendon and ligament injuries with the use of mesenchymal stromal cells (MSCs) obtained from two different sources: amniotic membrane (AMSCs) and bone marrow (BM-MSCs). The objective was to prove the ability of AMSCs to exert beneficial effects in vivo.

METHODS

Five million allogeneic frozen-thawed AMSCs or autologous fresh BM-MSCs were injected intralesionally in horses belonging to group A (51 horses) and group B (44 horses). The interval lesion/implantation was of 6-15 days for the AMSCs and 16-35 days for the BM-MSCs. Healing was assessed clinically and ultrasonographically. Follow-up was monitored for 2 further years from return to full work.

RESULTS

No significant adverse effects after MSCs treatment were seen in any of the horses studied, independent of the type of stromal cell implanted. All animals belonging to group A resumed their activities between 4-5 months after treatment, whereas animals of group B resumed their activities after 4-12 months. The rate of re-injury in horses treated with AMSCs is lower (4.00%) compared with the average observed when horses were treated with BM-MSCs (23.08%).

CONCLUSIONS

The possibility to inject allogeneic AMSCs in real time, before any ultrasonographic change occurs within the injured tendon and ligament, together with the higher plasticity and proliferative capacity of these cells compared with BM-MSCs, represents the main features of interest for this novel approach for the treatment of equine tendon diseases. An obvious active proliferative healing in the area injected with AMSCs makes these cells more effective than BM-MSCs.

Characteristics of equine mesenchymal stem cells derived from amnion and bone marrow: in vitro proliferative and multilineage potential assessment

REASONS FOR PERFORMING STUDY

This is the first study comparing stemness features of equine mesenchymal progenitor cells derived from amniotic membrane and bone marrow.

OBJECTIVES

To investigate an alternative and noninvasive stromal cell source for equine tissue engineering.

STUDY DESIGN

In vitro experimental study of the characteristics of equine mesenchymal progenitor cells derived from amnion and bone marrow.

METHODS

Cells isolated from amniotic membrane and bone marrow were analysed for proliferation (growth curve, doubling time, colony forming unit). Immunocytochemical detection of pluripotency markers and gene expression of stromal cell markers were also performed and these cells were studied for multilineage plasticity.

RESULTS

Amniotic stromal cells (AMSCs) and bone marrow mesenchymal cells (BM-MSCs) both exhibited mature stromal cell-specific gene expression and immunocytochemical properties, but showed substantial differences in their proliferative and differentiation potential. The mean doubling time for AMSCs was significantly lower (P<0.05) than that observed for BM-MSCs (1.17 ± 0.15 vs. 3.27 ± 0.19 days, respectively). Compared to AMSCs, BM-MSCs also demonstrated a significantly (P<0.05) lower clonogenic capability (one fibroblast-like colony forming unit from a mean of 590.15 cells seeded for BM-MSCs vs. 242.73 cells seeded for AMSCs). BM-MSCs did not differentiate into glial cells, and the osteogenic differentiation process was longer than for AMSCs.

CONCLUSIONS AND POTENTIAL RELEVANCE

The amniotic membrane could be a valuable source of MSCs to be used both for allogenic and/or autologous therapies. The noninvasive nature and low cost of collection, the rapid proliferation along with a greater differentiation potential and the 'off the shelf' preparation potential could make AMCs useful for cell therapy.

Fluorescent multiple staining and CASA system to assess boar sperm viability and membranes integrity in short and long-term extenders

The aim of this study was to assess the effect on boar spermatozoa quality of in vitro storage in short and long-term extenders by fluorescent multiple staining (FMS) and computer assisted semen analyzer (CASA). Fresh ejaculates from three healthy, sexually mature boars were diluted with equal volumes of six short-term or three long-term commercial extenders and stored at 19°C for 6 days (short-term) or 12 days (long-term). The integrity of spermatozoa membranes was analyzed by FMS using propidium iodide, 5,5',6,6'-tetrachloro-1,1',3,3' tetraethylbenzimidazolyl-carbocyanine iodide (JC-1) and fluorescein isothiocyanate-conjugated peanut agglutinin (PNA). The results obtained from this staining were compared with spermatozoa motility assessed by CASA. Our study showed that the number of viable spermatozoa with non-reacted acrosomes and intact mitochondria was positively correlated with the rate of motile spermatozoa (r(2)>0.9) irrespective of the extender used. In all extenders the number of motile spermatozoa significantly decreased as preservation period increased (P<0.05). FMS test is a potent indicator of sperm motility because it analyses mitochondrial integrity independently from observable alterations in motility. The best performing extenders were BTS for short-term storage and TRI-x-Cell for long-term storage.

295 EQUINE AMNION-DERIVED MESENCHYMAL STEM CELLS: POSSIBLE IMPLICATION IN ENDOMETRIAL REGENERATION

In veterinary medicine, as in human, amnion is an attractive source of mesenchymal stem cells (MSC), which poses no ethical dilemmas, allows highly efficient recovery of cells without the requirement of invasive procedures and shows immunomodulatory properties. We previously demonstrated that equine amniotic membrane-derived cells (AMC) not only exhibit specific stem cell properties with respect to expression of pluripotent (OCT-4, TRA-1-60, and SSEA-4) and adult (CD44, CD105, CD29, and CD166) stem cell markers but also possess differentiation potential in vitro and the capability to regenerate tendons in vivo after spontaneous lesions when allogeneically transplanted. Moreover, we reported evidence that at the first passages (P) in culture (until P5), AMC express MHC-class I but not MHC-class II and are well tolerated in vivo. In the present study, we further characterised AMC in vitro in order to evaluate their potential application in the treatment of endometritis in vivo. In particular, the amniotic membrane in toto and AMC have been compared to the endometrial tissue in toto and to cells isolated from endometrium for the expression of genes involved in the proliferation and differentiation of uterine MSC during early pregnancy (AbdB-like Hoxa genes) and those influencing preimplantation conceptus development (progesterone receptor, PR, and oestrogen receptors ERα and ERβ). The AMC were isolated as recently reported by Lange-Consiglio et al. (2011 Open J. Tissue Eng. Regen. Med. 4), and endometrial cells were obtained according to the protocol described by Donofrio et al. (2008 Reprod. Biol. Endocrinol. 6, 65) for bovine cells, and slightly modified for equine cells. Total RNA was extracted from both tissues and from AMC and endometrium-derived cells immediately after isolation (P0). Reverse transcription-PCR was performed according to the standard procedures, using GAPDH and HPRT1 as reference genes. Expression of HOXA9 and PR was confirmed in all samples examined, whereas mRNA for ERβ was only detected in endometrial tissue and in cells derived from it. Expression of ERα was observed only in endometrial tissue. The expression of genes crucially involved in patterning of the female reproductive tract (HOXA9 and PR) in amnion and cells derived from it suggests that this source shares similar molecular properties with endometrium. Further studies are required to explore uterine mesenchymal-like features shared by AMC (i.e. verifying the expression of Wnt7α, Wnt5α, and Wnt4α, or the presence of the more recently characterised membrane-bound intracellular progesterone receptors PGRMC1 and mPR). These preliminary results provide an intriguing indication of the possible implication of amnion-derived cells in endometrial regeneration, in particular when poor endometrial proliferation is associated with infertility or poor pregnancy outcome.

163 HYPERACTIVATION OF STALLION SPERM IN FOLLICULAR FLUID FOR IN VITRO FERTILIZATION OF EQUINE OOCYTES

In vitro fertilization has remained elusive in the horse, as evidenced by low sperm penetration rates when IVF has been attempted with in vivo- or in vitro-matured oocytes. It is likely that the low sperm penetration rates observed in IVF studies are due to the inability to appropriately capacitate or hyperactivate, or both, stallion sperm in the laboratory. The acquisition of hyperactivated sperm motility has been observed within the oviducts of mammals at the time of fertilization and is required for zona pellucida penetration in conjunction with the acrosome reaction (AR). Although the zona pellucida is considered the prime physiological inducer of AR, previous studies have shown a low incidence of AR in zona pellucida-bound stallion spermatozoa after 1 h of in vitro binding. This low incidence suggests that, besides the zona pellucida glycoproteins, another major factor might be responsible for AR. Protein-bound progesterone, present in equine follicular fluid (FF), has been demonstrated to induce AR in stallion spermatozoa. In this context, the aims of this study were (1) to hyperactivate stallion sperm in FF and (2) to verify whether this hyperactivation supports equine IVF. Pooled FF, aspirated from the preovulatory follicles of oestrous mares, was used and its progesterone concentration was determined by immune enzymatic assay. Spermatozoa from fertile stallions selected by a swim-up procedure were pre-incubated for 6 h in capacitating medium (modifed Whittens's medium (WM) supplemented with 25 mM NaHCO3 and 7 mg mL–1 of BSA) and then incubated for 6 h at 37°C in either FF or capacitating WM. Sperm motility was assayed by computer-assisted semen analysis, rates of AR were assessed by fluorescein isothiocyanate-PNA staining and rate of apoptosis was assessed by an annexin V test. For IVF, spermatozoa were incubated at 10 × 106 sperm mL–1 in capacitating WM for 6 h and then diluted to 1 × 106 sperm mL–1 in capacitating WM with or without 10% of FF. Five mature mare oocytes were transferred into droplets (100 μL) of the sperm suspensions covered with mineral oil and then incubated for 18 h at 38.5°C in 5% CO2 in humidified air. After that, oocytes were transferred to an embryo culture medium (DMEM/F-12) for an additional 3 days. Data were analysed by ANOVA. Treatment of sperm with FF resulted in a significant (P ≤ 0.05) decrease of 3 motility variables indicative of hyperactivation: straight line velocity, straightness and linearity. The highest rate of AR (29.44%) and a lower rate of apoptosis (16.93%) were obtained after 4 h of incubation in follicular fluid. By coupling capacitating conditions with the induction of hyperactivation using follicular fluid, we have obtained reproducible percentages of 8-cell-stage embryos (18.56%) in our IVF experiments. Conversely, sperm incubated in capacitating conditions but not treated with FF did not fertilize (0%). It is concluded that mare FF does not impair sperm viability, stimulates equine sperm hyperactivation in vitro, induces the AR and supports equine IVF.

Characterization and potential applications of progenitor-like cells isolated from horse amniotic membrane

The aim of this work was to isolate, for the first time, progenitor-like cells from the epithelial (AECs) and mesenchymal (AMCs) portions of the horse amniotic membrane, and to define the biological properties of these cells. AECs displayed polygonal epithelial morphology, while AMCs were fibroblast-like. Usually, six to eight passages were reached before proliferation decreased, with 13.08 and 26.5 cell population doublings attained after 31 days for AECs and AMCs, respectively. Immunocytochemical studies performed at passage 3 (P3) showed that both cell populations were positive for the expression of specific embryonic markers (TRA-1-60, SSEA-3, SSEA-4 and Oct-4). Meanwhile, RT-PCR performed at P1 and P5 showed expression of mesenchymal stem/stromal cell markers (CD29, CD105, CD44 and CD166) with negativity for CD34 at P1, although this marker began to be expressed by P5. The cells also expressed MHC-I at both P1 and P5, but lacked MHC-II expression at P1. Both AECs and AMCs demonstrated high plasticity, differentiating in vitro toward the osteogenic, adipogenic, chondrogenic and neurogenic lineages. Equine amnion-\derived cells could also be frozen and recovered without loss of their functional integrity in terms of morphology, presence of specific stemness markers and differentiation ability, although the renewal capacity was lower than that observed for freshly isolated cells. To investigate potential therapeutic effects and cell tolerance in vivo, horse amnion-derived cells were allogeneically injected into three horses with tendon injuries, resulting in a quick reduction in tendon size and ultrasonographic cross-sectional area measurements. These results suggest that horse amnion-derived cells may be useful for cell therapy applications.

Size-sieved subpopulations of mesenchymal stem cells from intervascular and perivascular equine umbilical cord matrix

OBJECTIVES

Umbilical cord matrix (UCM) has been recently proposed as an alternative source of mesenchymal stem cells (MSCs). The aim of this study was to isolate and characterize presumptive stem cells from intervascular and perivascular equine UCM and to obtain homogeneous subpopulations from both sites.

MATERIALS AND METHODS

Umbilical cords were processed for retrieval of MSCs. Unsieved cells from intervascular and perivascular portions were evaluated for cell cycle analysis and for immunophenotyping by flow cytometry. Cells from each site were separated into larger and smaller sieved populations using multi-dishes with 8-μm pore transwell inserts. Each cell population was characterized in terms of renewal capability, specific marker expression and differentiation potential. Cryopreservation was performed on sieved cells only.

RESULTS

Cells from both areas expressed MSC and pluripotential specific markers and were able to differentiate into mesodermic and ectodermic lineages. The sieving procedure yielded two relatively homogeneous subpopulations with comparable characteristics. Surprisingly, after sieving, large intervascular and small perivascular cells were the most rapidly replicating cells [20.53 and 19.49 cell population doublings (PD) after 31 days respectively] and also showed higher fibroblast colony forming unit frequency. Unsieved cell populations were used as controls, and showed PD of 9.42(intervascular cells) and 8.54 (perivascular cells) after 31 days.

CONCLUSIONS

Here, cells from UCM represented an intermediate stage between pluripotent embryonic and adult stem cells. Size-sieving can be used to isolate more rapidly proliferating cell populations.

Isolation, proliferation, cytogenetic, and molecular characterization and in vitro differentiation potency of canine stem cells from foetal adnexa: a comparative study of amniotic fluid, amnion, and umbilical cord matrix

The possibility to isolate canine mesenchymal stem cells (MSCs) from foetal adnexa is interesting since several canine genetic disorders are reported to resemble similar dysfunctions in humans. In this study, we successfully isolated, cytogenetically and molecularly characterized, and followed the differentiation potency of canine MSCs from foetal adnexa, such as amniotic fluid (AF), amniotic membrane (AM), and umbilical cord matrix (UCM). In the three types of cell lines, the morphology of proliferating cells typically appeared fibroblast-like, and the population doubling time (DT) significantly increased with passage number. For AF- and AM-MSCs, cell viability did not change with passages. In UCM-MSCs, cell viability remained at approximately constant levels up to P6 and significantly decreased from P7 (P < 0.05). Amnion and UCM-MSCs expressed embryonic and MSC markers, such as Oct-4 CD44, CD184, and CD29, whereas AF-MSCs expressed Oct-4, CD44. Expression of the hematopoietic markers CD34 and CD45 was not found. Dog leucocyte antigens (DLA-DRA1 and DLA-79) were expressed only in AF-MSCs at P1. Isolated cells of the three cell lines at P3 showed multipotent capacity, and differentiated in vitro into neurocyte, adipocyte, osteocyte, and chondrocyte, as demonstrated by specific stains and expression of molecular markers. Cells at P4 showed normal chromosomal number, structure, and telomerase activity. These results demonstrate that, in dog, MSCs can be successfully isolated from foetal adnexa and grown in vitro. Their proven stemness and chromosomal stability indicated that MSCs could be used as a model to study stem cell biology and have an application in therapeutic programs.