Mouse placental scaffolds: a three-dimensional environment model for recellularization

The rich extracellular matrix (ECM) and availability make placenta eligible as alternative biomaterial source. Herein we produced placental mouse scaffolds by decellularization, and structure, composition, and cytocompatibility were evaluated to be considered as a biomaterial. We obtained a cell-free scaffold containing 9.42 ± 5.2 ng dsDNA per mg of ECM, presenting well-preserved structure and composition. Proteoglycans were widespread throughout ECM without cell nuclei and cell remnants. Collagen I, weak in native placenta, clearly appears in the scaffold after recellularization, opposite distribution was observed for collagen III. Fibronectin was well-observed in placental scaffolds whereas laminin and collagen IV were strong expressed. Placental scaffolds recellularization potential was confirmed after mouse embryonic fibroblasts 3D dynamic culture, resulting in massive scaffold repopulation with cell–cell interactions, cell-matrix adhesion, and maintenance of natural morphology. Our small size scaffolds provide a useful tool for tissue engineering to produce grafts and organ fragments, as well as for cellular biology purposes for tridimensional culture substrate.

Establishment of 3-dimensional scaffolds from hemochorial placentas

INTRODUCTION

The extracellular matrix (ECM) is a complex, tissue-specific 3-dimensional network that controls cell processes. ECMs derived from various organs are used to produce biological scaffolds comparable to the native microenvironment. Although placentas are often overlooked, they offer a rich ECM for tissue engineering, especially the hemochorial placentas from rodents and lagomorphs that resemble the ones from humans.

METHODS

Here we established a protocol for decellularization and investigated the ECM in native and decellularized placentas of guinea pigs, rats and rabbits by means of histology, immunohistochemistry, immunofluorescence and scanning electron microscopy.

RESULTS

Effective decellularization were achieved by immersion in 0.25% Sodium Dodecyl Sulfate for 3 days, resulting in an intact ECM, while cells or nuclei were absent. All species had a high diversity of ECM components that varied between areas.

DISCUSSION

Dense fibrous networks in the junctional zone were strongly positive to collagen I, III and IV, fibronectin, and laminin ECM markers. Noticeable response were also found for the decidua, especially along the maternal vessels. The labyrinth had thin fibers strongly positive for fibronectin and laminin, but not much for collagens. In conclusion, we established an effective protocol to obtain biological scaffolds from animal models with hemochorial placentas that possessed promising values for future purposes in Regenerative Medicine.

Morphological characteristics of mule conceptuses during early development

Hybrids between species are often infertile and extremely rare among mammals. Mules, i.e. crossing between the horse and the donkey, on the other hand are very common in agricultural and leisure practices due to their enhanced post-natal physical characteristics that is believed to occur for outbreeding or hybrid vigor. Since no reports are availableon the effects of hybrid vigor during early development, this study focused on characterizing the intrauterine development of mule conceptuses during critical embryo-to-fetus transition period. Nine embryos and fetuses of early gestation, obtained after artificial insemination and transcervical flushing, were evaluated by means of gross anatomy and histology and compared to data available for the equine. We found that some events, such as C-shape turning, apearence of branchial archs, limb and tail buds, formation of primary and secondary brain vesicles, heart compartmentalization, and development of somites, occurred slightly earlier in the mule. Nonetheless, no major differences were observed in other developmental features, suggesting similarities between the mule and the horse development. In conclusion, these data suggest that the effect of hybrid vigor is present during intrauterine development in the mule, at least with regard to its maternal parent.

Optimization of Canine Placenta Decellularization: An Alternative Source of Biological Scaffolds for Regenerative Medicine

Due to the scarcity of tissues and organs for transplantation, the demand for bioengineered tissues is increasing with the advancement of technologies and new treatments in human and animal regenerative medicine. Thus, decellularized placental extracellular matrix (ECM) has emerged as a new tool for the production of biological scaffolds for subsequent recellularization and implantation for recovery of injured areas or even for replacement of organ and tissue fractions. To be classified as an ideal biological scaffold, the ECM must be acellular and preserve its proteins and physical features to be useful for cellular adhesion. In this context, we developed a process of decellularization of canine placentas with 35 and 40 days of gestation using dodecyl sulfate sodium under immersion and agitation in sterile conditions. Before use of this scaffold in recellularization processes, the decellularization efficiency needs to be confirmed by the absence of cellular content and an irrelevant amount of reminiscent DNA. Both vasculature architecture and ECM proteins, such as collagen types I, III, and IV, laminin, and fibronectin, were preserved with our method. In this way, we established a new biological scaffold model that could be used for recellularization in regenerative medicine of tissues.

Reproductive system development in male and female horse embryos and fetuses: Gonadal hyperplasia revisited

In horses, pregnancy is characterized by high levels of maternal estrogens that are produced largely by the interstitial tissue inside the gonads of the offspring, associated with a physiological gonadal hyperplasia, that is uncommon in other species. However, a detailed structural-functional understanding of the early stages of gonadal development and hyperplasia has remained elusive in horse pregnancy because of the lack of substantial data. The goal of this study was to describe the genital organs' development in 19 early horse embryos and fetuses (days 20-140 of gestation) of both sexes by means of anatomy, histology, stereology, and immunohistochemistry, with a specific focus on gonadal hyperplasia and interstitial tissue development. Gonadal hyperplasia with similar amounts of interstitial cells was observed in both sexes, but only during the early stage of development (days 40-90). Surprisingly, a higher degree of hyperplasia, characterized by larger amounts of interstitial cell-rich areas, was seen in fetal ovaries from 90 days of gestation onwards. Another novel aspect was that parallel to the hyperplasia of the interstitial cells, a much more precocious and pronounced differentiation of germinal cells was seen in the ovary, characterized by an earlier peak and decrease of DAZL and OCT protein immune markers. In conclusion, a reduced degree of hyperplasia and interstitial tissue in the fetal testis after 90 days of gestation suggests the existence of a more efficient mechanism regarding the synthesis of estrogen precursors as a structural or physiological difference between both fetal sexes, which warrants further investigation.

Decellularized bovine cotyledons may serve as biological scaffolds with preserved vascular arrangement

Technically produced scaffolds are common to establish transplantable tissues for regenerative medicine, but also biological ones that are closer to the natural condition become of interest. Placentas are promising, because they represented available, complete organs with rich extracellular matrix (ECM) and well-developed vasculature that easily could build anastomoses to a host's organ. Only placentas from larger animal models such as the bovine meet the dimensions large enough for most organs but are not adequately described yet. We here studied the nature of the ECM in 27 natural and decellularized bovine cotyledons, that is, the fetal part of the placentomes, by means of histology, immunohistochemistry, and electron microscopy. Successful decellularization was done by perfusion with 0.01%, 0.1%, and 0.5% sodium dodecyl sulfate each and subsequent immersion in 1% Triton X-100, resulting in a removal of cells and DNA, whereas the structure of the allantochorionic surface and villi was preserved. Although some fibres disappeared, also the arrangement of the main ECM proteins was largely similar before and after decellularization: Along the larger vessels, a densely packed network of thick fibres occurred, organized in layers without cells or spaces in between. Collagen IV, fibronectin, and laminin contributed to those areas. In contrast, collagen I and III characterized the meshwork of medium-sized and thin fibres in the mesenchyme, respectively. In conclusion, decellularized bovine cotyledons indeed had characteristics of a biological scaffold and provide an interesting alternative to develop large-scale scaffolds with complex vascular architecture for tissue engineering purposes.

Placentation in the colugos Cynocephalus volans and Galeopterus variegatus (Dermoptera) and the transition from labyrinthine to villous placentation in primates

INTRODUCTION

Phylogenetics and genomics place colugos as the sister group to primates. Therefore their placentation is of interest in an evolutionary perspective. Previous accounts are fragmentary, not readily accessible and sometimes contradictory.

METHODS

We have examined archival material covering the early development of fetal membranes and placenta, the fate of the yolk sac and definitive placentation.

RESULTS

Initially the trophoblast extended over a rather broad but shallow area, enclosing maternal blood spaces. After expansion of the exocoelom it became covered by somatic mesoderm. The mature chorioallantoic placenta was haemochorial and characterized by a labyrinth with markedly dilated maternal blood spaces. Blood vessels appeared in the splanchnopleure early in development and later extended to the yolk sac, but we found no evidence of a choriovitelline placenta at any stage of gestation. There was, however, an extensive paraplacenta.

CONCLUSIONS

A choriovitelline placenta is not formed early in gestation nor is it present at term. Early in development invasive trophoblast spreads laterally to form a trophoblastic plate. We found evidence to support the idea that the colugo placenta is intermediate between the labyrinthine placenta of rodents and the trabecular type of Neotropical primates.

Cochlear epithelial of dog fetuses: a new source of multipotent stem cells

Hearing loss caused by the damage of cochlea sensory cells or neurons is a common human disease, but also affects dogs and other animals. To test their progenitor nature as potential value for future therapies, we characterized cells derived from the cochlear epithelium in dog fetuses. In total, 8 fetuses of 35-40 days of gestation, derived from castration campaigns, were investigated. Cells were analysed by the MTT colorimetric assay and in regard to cell cycle, differentiation capacities, immunophenotypes and qPCR analysis. In culture, cells had a fibroblast-like morphology. Phenotypic immunocharacterization showed positive staining for mesenchymal stem cell and pluripotency markers and were negative for hematopoietic cell markers. Cells possessed differentiation capacity for the three main cell lineages: osteogenic, adipogenic and chondrogenic, altogether indicating their nature as mesenchymal stem cells. Thus, cells derived from fetal cochlear tissues indeed may provide valuable sources of progenitor cells for cell therapy of canine deafness and other diseases.

Pilot study: bone marrow stem cells as a treatment for dogs with chronic spinal cord injury

Background

Chronic Spinal Cord injury is a common, severe, and medically untreatable disease. Since the functional outcomes of acute and experimental chronic spinal cord injury have been shown to improve with stem cell therapy, a case study was conducted to test if the application of stem cell also regenerates chronic SCI dysfunction. Transplantation of foetal bone marrow stem cells was applied in seven dogs with chronic spinal cord injury. Magnetic resonance images and assessments of symptoms according to the Olby scale were used to diagnose the severity of injury.

Result

All dogs improved locomotor and sensory function when examined 90 days after surgery, and showed increased movement of the hind limbs, and were able to stand upright, as well as to take small steps. Tail tone was observed in seven dogs, pain reflexes and defecation return were observed in five dogs.

Conclusion

The transplantation of bone marrow stem may be a promising, reliable and safe treatment for chronic spinal cord injury.

Electronic supplementary material

The online version of this article (doi:10.1186/2050-490X-2-9) contains supplementary material, which is available to authorized users.

Evolution of the interhaemal barrier in the placenta of rodents

A recent phylogenetic analysis achieved good resolution between the 5 suborders of rodent. As a novel finding it suggested a basal split that gave rise to a monophyletic group comprising Hystricomorpha and Sciuromorpha. We asked whether the new tree could cast light on the evolution of the interhaemal barrier in rodents where at least seven variants have been described. To supplement existing data we first examined the placenta of the common gundi, Ctenodactylus gundi. It was shown to be haemochorial with a single layer of syncytiotrophoblast in the interhaemal membrane but with nests of cytotrophoblast elsewhere. Next we used character mapping on the recent tree to determine the pattern of evolution of the placenta with respect to principal type (e.g. haemochorial) and the trophoblast found within the interhaemal barrier. This indicated that the common ancestor of living rodents had a haemochorial placenta and that there were two independent transformations to the endotheliochorial type. Moreover, the interhaemal barrier was found to have had a single layer of syncytial trophoblast in the common ancestor of rodents, a condition that was retained in the clade comprising Hystricomorpha and Sciuromorpha. In contrast the second clade shows multiple character transformations.