Placental scaffolds as a potential biological platform for embryonic stem cells differentiation into hepatic-like cells lineage: A pilot study

Hepatic microenvironment plays an essential role in liver regeneration, providing the necessary conditions for cell proliferation, differentiation and tissue rearrangement. One of the key factors for hepatic tissue reconstruction is the extracellular matrix (ECM), which through collagenous and non-collagenous proteins provide a three-dimensional structure that confers support for cell adhesion and assists on their survival and maintenance. In this scenario, placental ECM may be eligible for hepatic tissue reconstruction, once these scaffolds hold the major components required for cell support. Therefore, this preliminary study aimed to access the possibility of mouse embryonic stem cells differentiation into hepatocyte-like cells on placental scaffolds in a three-dimensional dynamic system using a Rotary Cell Culture System. Following a four-phase differentiation protocol that simulates liver embryonic development events, the preliminary results showed that a significant quantity of cells adhered and interacted with the scaffold through outer and inner surfaces. Positive immunolabelling for alpha fetus protein and CK7 suggest presence of hepatoblast phenotype cells, and CK18 and Albumin positive immunolabelling suggest the presence of hepatocyte-like phenotype cells, demonstrating the presence of a heterogeneous population into the recellularized scaffolds. Periodic Acid Schiff-Diastase staining confirmed the presence of glycogen storage, indicating that differentiate cells acquired a hepatic-like phenotype. In conclusion, these preliminary results suggested that mouse placental scaffolds might be used as a biological platform for stem cells differentiation into hepatic-like cells and their establishment, which may be a promissing biomaterial for hepatic tissue reconstruction.

Decellularized Vascular Scaffolds Derived from Bovine Placenta Blood Vessels

OBJECTIVES

Diseases associated with the circulatory system are the main causes of worldwide morbidity and mortality, implying the need for vascular implants. Thus, the production of vascular biomaterials has proven to be a promising alternative to therapies used in studies and research related to vascular physiology. The present project aims to achieve the artificial development of blood vessels through the recellularization of vascular scaffolds derived from bovine placental vessels.

METHODS

The chorioallantoic surface of the bovine placenta was used to produce decellularized biomaterials. For recellularization, 2.5 x 104 endothelial cells were seeded above each decellularized vessel fragment during three or seven days, when culture were interrupted, and the fragments were fixed for cell attachment analysis. Decellularized and recellularized biomaterials were evaluated by basic histology, scanning electron microscopy, and immunohistochemistry.

RESULTS

The decellularization process produced vessels that maintained natural structure and elastin content, and no cells or gDNA remains were observed. Endothelial precursor cells were also attached to lumen and external surface of the decellularized vessel.Conclusion: Our results show a possibility of future uses of this biomaterial in cardiovascular medicine, as in the development of engineered vessels.

Term alpaca placenta glycosylation profile and its correlation with pregnancy maintenance and fetal survival

Alpaca is a South American camelid, particularly present in Peruvian highlands, where oxygen concentration and atmospheric pressure are very low. Due to this fact, gestational physiology has adapted to preserve the conceptus' and mother's health. In this context, several cellular and molecular features play an essential role during and at the end of gestation. Structural carbohydrates act on maternal-fetal communication, recognize exogenous molecules, and contribute to placental barrier selectivity. Therefore, this study aimed to characterize the structural carbohydrate profiles that are present in the term alpaca placenta, kept in their natural habitat of around 4,000 m height. For this propose, 12 term alpaca placentas were collected, and the material was obtained at the time of birth from camelids raised naturally in the Peruvian highlands, in the Cusco region. All placenta samples were processed for histological analysis. A lectin histochemical investigation was performed using 13 biotinylated lectins, allowing us to determine the location of carbohydrates and their intensity on a semi-quantitative scale. Our results demonstrated that during term gestation, the epitheliochorial alpaca placenta shows a high presence of carbohydrates, particularly glucose, α-linked mannose, N-acetylglucosamine β (GlcNAc), galactose (αGal), and N-acetylgalactosamine α (GalNAc), present in the trophoblast, amnion epithelium, and mesenchyme, as well as the presence of sialic acid residues and low affinity for fucose. In fetal blood capillaries, the presence of bi- and tri-antennary complex structures and α-linked mannose was predominated. In conclusion, we characterized the glycosylation profile in the term alpaca placenta. Based on our data, compared to those reported in the bibliography, we suggest that these carbohydrates could participate in the labor of these animals that survive in Peruvian extreme environments.

Development of a new decellularization protocol for the whole porcine heart

BACKGROUND

Cardiovascular diseases are the leading cause of death in many countries. Advances in technology have been promoted in this regard, especially in tissue engineering, to meet the need for tissue or organ grafts. In this way, the porcine model has been used due to its morphophysiological similarity between the human species, mainly regarding the cardiovascular system. Tissue engineering is employed using biological scaffolds that are currently derived from porcine. These scaffolds are produced by decellularization, a process to remove cells aiming to maintain only its three-dimensional structure, formed by extracellular matrix (ECM). Its main objective is to produce organs through recellularized scaffolds that could eventually substitute the ones with impaired functions.

AIM

In this way, the present study aimed to establish a new protocol for porcine heart decellularization with potential application on tissue engineering.

METHODS

A porcine heart aorta was cannulated with a silicon tube, and the organ was washed in 0.1% phosphate-buffered saline through a peristaltic pump (Harvard Peristaltic Pump - Harvard Apparatus). After that, deionized water was introduced in the same system. The decellularization procedure was carried out using ionic and non-ionic detergents, namely 4% sodium dodecyl sulfate (SDS) and 1% Triton X-100, respectively. SDS was perfused through myocardial circulation at 400 mL/min for 24 h for 6 days. Subsequently, the heart was infused with Triton X-100 and washed by PBS and water for 24 h. The heart volume was measured before and after the recellularization. After macroscopic evaluation, the heart samples were processed and stained by Hematoxylin and Eosin, Masson's Trichrome, Weigert-Van Gieson, Alcian Blue, and Pricrosirius Red techniques for microscopic analysis. To observe the cell adhesion, the recellularization was provided in this scaffold, which was analyzed under immunofluorescence and scanning electronic microscopy.

RESULTS

The protocol provided cells remotion, with adequate concentration of remaining DNA. ECM components as collagen type I, elastin, and glycosaminoglycans were successfully maintained. The scaffold showed a high cells adherence and proliferation in the recellularization process.

CONCLUSION

According to results, the protocol described in this work preserved the ECM components and the organ architecture, minimizing ECM loss and being possible to state that it is a promising approach to tissue bioengineering.

RELEVANCE FOR PATIENTS

This study provides a protocol for whole porcine heart decellularization, which will ultimately contribute to heart bioengineering and may support further studies on biocompatibility relationship of new cells with recellularized scaffolds.

Calotropis procera (Aiton) Dryand (Apocynaceae) as an anti-cancer agent against canine mammary tumor and osteosarcoma cells

Our goal was to evaluate phytochemical characterization and the antitumor potential of Calotropis procera. The phytochemical constitution of the crude extract (CE) revealed the presence of flavonoids, glycosides and cardenolide. The MTT assay was used to evaluate the cytotoxicity of CE, methanolic (MF) and ethyl acetate fractions (EAF) of C. procera in canine osteosarcoma cells (OST), canine mammary tumor (CMT), and canine skin fibroblasts (non-tumor cell). Doxorubicin was also used as a positive control. Results showed that CE, MF and EAF promoted a decrease in the viability of OST and CMT cells and did not alter the fibroblasts viability. C. procera also decreased the number of cells, corroborating to the decrease in proliferation and the cell cycle arrest in the G0/G1 phase. It was also evaluated the cell morphology by light and fluorescence microscopy, being demonstrated a reduction in cytoplasmic and cell rounding characteristic of programmed cell death. Moreover, flow cytometry data demonstrated that CE treatment promoted increase of caspase-3 and p53, showing that the cell death was activated in OST cells. In addition, there was a decrease in CD31, VEGF, osteopontin and TGF-β after CE treatment, suggesting that CE exerts its antitumor effect by reducing angiogenesis and tumor progression in OST cells. Moreover, CMT cells showed a reduction in PCNA after treatment with MF and CE. Analyzing the data together, C. procera, especially CE, showed an antitumor potential in both OST and CMT cells, encouraging us to continue investigating its use in cancer therapy.

Placental scaffolds have the ability to support adipose-derived cells differentiation into osteogenic and chondrogenic lineages

Prudent choices of cell sources and biomaterials, as well as meticulous cultivation of the tissue microenvironment, are essential to improving outcomes of tissue engineering treatments. With the goal of providing a high-quality alternative for bone and cartilage tissue engineering, we investigated the capability of bovine placental scaffolds to support adipose-derived cell differentiation into osteogenic and chondrogenic lineages. Decellularized bovine placenta, a high-quality scaffold with practical scalability, was chosen as the biomaterial due to its rich extracellular matrix, well-developed vasculature, high availability, low cost, and simplicity of collection. Adipose-derived cells were chosen as the cell source as they are easy to isolate, nontumorigenic, and flexibly differentiable. The bovine model was chosen for its advantages in translational medicine over the mouse model. When seeded onto the scaffolds, the isolated cells adhered to the scaffolds with cell projections, established cell-scaffold communication and proliferated while maintaining cell-cell communication. Throughout a 21-day culture period, osteogenically differentiated cells secreted mineralized matrix, and calcium deposits were observed throughout the scaffold. Under chondrogenic specific differentiation conditions, the cells modified their morphology from fibroblast-like to round cells and cartilage lacunas were observed as well as the deposit of cartilaginous matrix on the placental scaffolds. This experiment provides evidence, for the first time, that bovine placental scaffolds have the potential to support bovine mesenchymal stem cell adherence and differentiation into osteogenic and chondrogenic lineages. Therefore, the constructed material could be used for bone and cartilage tissue engineering.

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.

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.

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.

Rabbit olfactory stem cells. Isolation protocol and characterization

PURPOSE

To describe a new technique for isolation of a mesenchymal stem cells (MSCs) population from the olfactory mucosa in rabbits.

METHODS

Olfactory stem cells (OSCs) were retrieved from under the cribriform plate of the Ethmoid bone. Several assays were accomplished to characterize the cell population and attest its viability in vitro. The cells were submitted to flow cytometry with the antibodies CD34, CD45, CD73, CD79, CD90 and CD105 and also they were induced to differentiate in three lineages. Functional evaluation involved analysis of in vitro growth behavior, colony forming unit like fibroblasts (CFU-f) and cryopreservation response. Further transduction with Green Fluorescent Protein (GFP) was also performed.

RESULTS

The OSCs showed mesenchymal features, as positive response to CD34, CD73 and CD90 antibodies and plasticity. Additionally, these cells have high proliferated rate, and they could be cultured through many passages and kept the ability to proliferate and differentiate after cryopreservation. The positive response to the transduction signalizes the possibility of cellular tracking in vivo. This is a desirable feature in case those cells are used for pre-clinical trials.

CONCLUSION

The cells harvested were mesenchymal stem cells and the technique described is therefore efficient for rabbit olfactory stem cells isolation.

Organogenesis of the Musculoskeletal System in Horse Embryos and Early Fetuses

Musculoskeletal system development involves heterotypical inductive interactions between tendons, muscles, and cartilage and knowledge on organogenesis is required for clarification of its function. The aim of this study was to describe the organogenesis of horse musculoskeletal system between 21 and 105 days of gestation, using detailed macroscopic and histological analyses focusing on essential developmental steps. At day 21 of gestation the skin was translucid, but epithelial condensation and fibrocartilaginous tissues were observed on day 25 of pregnancy. Smooth muscle was seen in lymphatic and blood vessel walls and the beginning of cartilaginous chondrocranium was detected at day 30 of gestation. At day 45, typical chondroblasts and chondrocytes were observed and at day 55, mandibular processes expanded toward the ventral midline of the pharynx. At day 75, muscles became thicker and muscle fibers were seen developing in carpal and metacarpal joints with the beginning of the ossification process. At day 105, major muscle groups, similar to those seen in an adult equine, were observed. The caudal area of the nasal capsule and trabecular cartilages increased in size and became ossified, developing into the ethmoid bone. The presence of nasal, frontal, parietal, and occipital bones was observed. In conclusion, novel features of equine musculoskeletal system development have been described here and each process was linked with an early musculoskeletal event. Data presented herein will facilitate a better understanding of the equine muscular system organogenesis and aid in the detection of congenital deformities. Anat Rec, 299:722-729, 2016. © 2016 Wiley Periodicals, Inc.

Fetal-maternal interactions in the synepitheliochorial placenta using the eGFP cloned cattle model

Background

To investigate mechanisms of fetal-maternal cell interactions in the bovine placenta, we developed a model of transgenic enhanced Green Fluorescent Protein (t-eGFP) expressing bovine embryos produced by nuclear transfer (NT) to assess the distribution of fetal-derived products in the bovine placenta. In addition, we searched for male specific DNA in the blood of females carrying in vitro produced male embryos. Our hypothesis is that the bovine placenta is more permeable to fetal-derived products than described elsewhere.

Methodology/Principal Findings

Samples of placentomes, chorion, endometrium, maternal peripheral blood leukocytes and blood plasma were collected during early gestation and processed for nested-PCR for eGFP and testis-specific Y-encoded protein (TSPY), western blotting and immunohistochemistry for eGFP detection, as well as transmission electron microscopy to verify the level of interaction between maternal and fetal cells. TSPY and eGFP DNA were present in the blood of cows carrying male pregnancies at day 60 of pregnancy. Protein and mRNA of eGFP were observed in the trophoblast and uterine tissues. In the placentomes, the protein expression was weak in the syncytial regions, but intense in neighboring cells on both sides of the fetal-maternal interface. Ultrastructurally, our samples from t-eGFP expressing NT pregnancies showed to be normal, such as the presence of interdigitating structures between fetal and maternal cells. In addition, channels-like structures were present in the trophoblast cells.

Conclusions/Significance

Data suggested that there is a delivery of fetal contents to the maternal system on both systemic and local levels that involved nuclear acids and proteins. It not clear the mechanisms involved in the transfer of fetal-derived molecules to the maternal system. This delivery may occur through nonclassical protein secretion; throughout transtrophoblastic-like channels and/or by apoptotic processes previously described. In conclusion, the bovine synepitheliochorial placenta displays an intimate fetal-maternal interaction, similar to other placental types for instance human and mouse.

Caracterização da fusão caruncular em gestações naturais e de conceptos bovinos clonados

O objetivo deste trabalho foi comparar as fusões carunculares em gestações de conceptos não clonados (CNC) e conceptos clonados (CC). Os CNC foram divididos segundo o período de gestação em Grupo I (2-3 meses, n=9), Grupo II (4-6 meses, n=9), Grupo III (7-8 meses, n=10) e Grupo IV (9 meses, n=7). Os CC formaram o Grupo V (9 meses, n=4). As carúnculas foram observadas macroscopicamente (número e dimensões: comprimento, largura e altura), microscopicamente e submetidas à análise estatística (5% de significância). Observaram-se três tipos de fusões carunculares macroscópicas: ovais (morfologicamente normais); duas carúnculas adjacentes unidas e do tipo lobuladas, caracterizadas por regiões com várias carúnculas unidas apresentando falsa fusão ou deformação do parênquima caruncular. O comprimento das carúnculas foi de 1,55±0,57; 2,45±0,55; 4,66±2,00 e 5,72±1,90cm para os Grupos I, II, III e IV, respectivamente. Quanto à altura, as carúnculas apresentaram um crescimento linear durante a gestação e foram de 0,40±0,15; 0;57±0,21; 1,00±0,48 e 1,80±0,91cm, para os respectivos Grupos I, II, III e IV. A largura das carúnculas foi semelhante entre os Grupos I e II (0,97±0,30 e 1,42±0,71cm) e os Grupos III e IV (2,68±1,22 e 3,52±1,16cm). Quando o Grupo V foi comparado ao Grupo IV, as carúnculas do Grupo V apresentaram maior comprimento (5,72±1,90 vs. 7,88±2,13cm) e largura (3,52±1,16 vs. 4,93±1,46cm), porém foram semelhantes em altura (1,80±0,91 e 2,25±0,67cm). Verificou-se que em gestações de CC, as carúnculas apresentaram maior desenvolvimento que em gestações de CNC. As carúnculas fusionadas apresentaram medidas estatisticamente semelhantes às isoladas em todos os parâmetros e grupos. Sob microscopia de luz, observou-se a formação de um eixo estromal, da base da carúncula ao ápice da fissura fusional, de constituição histológica semelhante ao estroma endometrial. Também foram ineditamente definidos três formatos microscópicos: fusão propriamente dita com eixo único, evidente abaixo da fissura fusional; pseudofusão com eixo duplo em forma de "H" e a falsa fusão com ausência do eixo. Os dois primeiros formatos referem-se às carúnculas ovais e lobuladas e o último à falsa fusão com deformação do parênquima caruncular. O eixo fusional aumentou de tamanho durante a gestação entre os Grupos I, II, III e IV. O Grupo V apresentou maior comprimento e largura de eixo quando comparado ao Grupo IV. Sendo assim, em gestações de CC a destruição do epitélio lateral das carúnculas está associada a uma incompetência na interdigitação materno-fetal, que comprometem a fusão cotiledonária. Sugere-se que, em gestações provenientes de CC, o aumento do tamanho das fusões carunculares possivelmente associa-se a um mecanismo compensatório para as trocas metabólicas entre mãe e feto, em razão do menor número de carúnculas isoladas.