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

The revolutionary role of placental derivatives in biomedical research

The human placenta is a transient yet crucial organ that plays a key role in sustaining the relationship between the maternal and fetal organisms. Despite its historical classification as "biowaste," placental tissues have garnered increasing attention since the early 1900s for their significant medical potential, particularly in wound repair and surgical application. As ethical considerations regarding human placental derivatives have largely been assuaged in many countries, they have gained significant attention due to their versatile applications in various biomedical fields, such as biomedical engineering, regenerative medicine, and pharmacology. Moreover, there is a substantial trend toward various animal product substitutions in laboratory research with human placental derivatives, reflecting a broader commitment to advancing ethical and sustainable research methodologies. This review provides a comprehensive examination of the current applications of human placental derivatives, explores the mechanisms behind their therapeutic effects, and outlines the future potential and directions of this rapidly advancing field.

Late-gestation heat stress alters placental structure and function in multiparous dairy cows

The placenta plays a pivotal role in fetal development and the dam's subsequent lactation performance, because it facilitates nutrient transfer, heat dissipation, and gas exchange with the growing fetus, and regulates key hormones essential for mammary gland development. Heat stress experienced during gestation and lactation can significantly reduce the placenta's capacity to perform these critical functions. To investigate the impact of heat stress, trials were conducted over the summer months of 2020, 2022, and 2023 in Florida. Multiparous pregnant Holstein cows were dried off 54 ± 5 d before their expected calving date and randomly assigned to 1 of 2 treatments for the entire dry period: active cooling (CL; access to barn shade, natural ventilation plus forced air circulation via fans, and water soakers; n = 20) or heat stress (HT; access to barn shade and natural ventilation; n = 20). Gestation length and calf birth weights were recorded. Placentas were collected from a subset of cows shortly after calving (4.00 ± 1.54 h; n = 10/treatment) and analyzed for total placental weight, as well as cotyledon weight, number, and surface area within 1 h after expulsion. A representative cotyledon sample was isolated for histological analysis. Tissues were also processed for RNA sequencing and DNA methylation analysis. DNA methylation was analyzed by double restriction enzyme reduced representation bisulfate sequencing. Differentially methylated cytosines between HT and CL were identified via logistic regression with a cut-off value of 15% methylation difference and a q-value <0.2. Morphological and histological data were analyzed using generalized linear mixed models. Results indicate that gestation length was shorter in HT cows compared with CL cows (274.2 vs. 277.2 ± 1.46 d), and heifers born to HT dams were lighter at birth (31.4 vs. 34.8 ± 1.59 kg). Placentas from HT dams tended to have lower total weight (3.54 vs. 4.54 ± 0.38 kg) and fewer cotyledons (66.2 vs. 103.3 ± 8.65). However, placental efficiency was higher in the HT versus CL group (11.5 vs. 8.52 ± 0.91%). Cotyledons from HT cows had greater vascular area (43.1% vs. 31.8% ± 10.4% of total area) and a tendency for less connective tissue (52.7% vs. 65.8% ± 5.39% of total area). A total of 289 differentially expressed genes were identified between HT and CL placentas, with 179 upregulated and 110 downregulated in the HT group. Key genes affected included NPSR1, SPATC1L, PGF, HSPB8, IL6, HBA/HBB, MMP12, PAPPA2, PAG14, and SLC7A10. Dysregulated pathways in HT placentas involved gas and oxygen transport, nutrient transport, inflammatory response, and cortisol biosynthesis. Heat stress induced hypermethylation of regulatory pathways, including collagen biosynthesis and degradation, extracellular matrix structural components, and placental tissue organization. Our findings demonstrate that late-gestation HT causes significant transcript alterations in the placenta, leading to adaptations for thermoregulation and morphological changes. These alterations negatively affect birth weight, health, and dam lactation performance, underscoring the need to address HT during late gestation to ensure optimal fetal development and postnatal outcomes. Addressing these issues can help improve dairy cow resilience to climate change, enhancing animal welfare and productivity.

Microvascular Engineering for the Development of a Nonembedded Liver Sinusoid with a Lumen: When Endothelial Cells Do Not Lose Their Edge

Microvascular engineering seeks to exploit known cell-cell and cell-matrix interactions in the context of vasculogenesis to restore homeostasis or disease development of reliable capillary models in vitro. However, current systems generally focus on recapitulating microvessels embedded in thick gels of extracellular matrix, overlooking the significance of discontinuous capillaries, which play a vital role in tissue-blood exchanges particularly in organs like the liver. In this work, we introduce a novel method to stimulate the spontaneous organization of endothelial cells into nonembedded microvessels. By creating an anisotropic micropattern at the edge of a development-like matrix dome using Marangoni flow, we achieved a long, nonrandom orientation of endothelial cells, laying a premise for stable lumenized microvessels. Our findings revealed a distinctive morphogenetic process leading to mature lumenized capillaries, demonstrated with both murine and human immortalized liver sinusoidal endothelial cell lines (LSECs). The progression of cell migration, proliferation, and polarization was clearly guided by the pattern, initiating the formation of a multicellular cord that caused a deformation spanning extensive regions and generated a wave-like folding of the gel, hinged at a laminin-depleted zone, enveloping the cord with gel proteins. This event marked the onset of lumenogenesis, regulated by the gradual apico-basal polarization of the wrapped cells, leading to the maturation of vessel tight junctions, matrix remodeling, and ultimately the formation of a lumen─recapitulating the development of vessels in vivo. Furthermore, we demonstrate that the process strongly relies on the initial gel edge topography, while the geometry of the vessels can be tuned from a curved to a straight structure. We believe that our facile engineering method, guiding an autonomous self-organization of vessels without the need for supporting cells or complex prefabricated scaffolds, holds promise for future integration into microphysiological systems featuring discontinuous, fenestrated capillaries.

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.

Mice Placental ECM Components May Provide A Three-Dimensional Placental Microenvironment

Bioethical limitations impair deeper studies in human placental physiology, then most studies use human term placentas or murine models. To overcome these challenges, new models have been proposed to mimetize the placental three-dimensional microenvironment. The placental extracellular matrix plays an essential role in several processes, being a part of the establishment of materno-fetal interaction. Regarding these aspects, this study aimed to investigate term mice placental ECM components, highlighting its collagenous and non-collagenous content, and proposing a potential three-dimensional model to mimetize the placental microenvironment. For that, 18.5-day-old mice placenta, both control and decellularized (n = 3 per group) were analyzed on Orbitrap Fusion Lumos spectrometer (ThermoScientific) and LFQ intensity generated on MaxQuant software. Proteomic analysis identified 2317 proteins. Using ECM and cell junction-related ontologies, 118 (5.1%) proteins were filtered. Control and decellularized conditions had no significant differential expression on 76 (64.4%) ECM and cell junction-related proteins. Enriched ontologies in the cellular component domain were related to cell junction, collagen and lipoprotein particles, biological process domain, cell adhesion, vasculature, proteolysis, ECM organization, and molecular function. Enriched pathways were clustered in cell adhesion and invasion, and labyrinthine vasculature regulation. These preserved ECM proteins are responsible for tissue stiffness and could support cell anchoring, modeling a three-dimensional structure that may allow placental microenvironment reconstruction.

Comparison between placental and skeletal muscle ECM: in vivo implantation

PURPOSE OF THE STUDY

Several tissues have been decellularized and their extracellular matrices used as allogeneic or xenogeneic scaffolds, either in orthotopic or heterotopic implantations, for tissue engineering purposes. Placentas have abundant matrix, extensive microvascular structure, immunomodulatory properties, growth factors and are discarded after birth, representing an interesting source of extracellular matrix. This study aimed at comparing decellularized canine placentas and murine skeletal muscles to regenerate skeletal muscles in a rat model.

MATERIALS AND METHODS

Muscle pockets were created at the posterior limbs of male Wistar rats, where the muscle- and placenta-derived extracellular matrices were implanted. Macroscopic, histological, and immunohistochemical analyses were performed after 3, 15, and 45 days of surgeries.

RESULTS

On the third day, intense inflammatory reaction, with macrophages (CD163⁺) and proliferative cells (PCNA⁺) being observed in control group and adjacent to the decellularized matrices. The percentage of proliferative cells was higher in placenta than in muscle matrices. Macrophages CD163^{+ high} were higher in muscles than in placentas, whereas CD163^{+ low} were higher in placentas than in muscle ECM, at days 3 and 15. Placental matrices were not completely degraded at day 15, as opposed to the muscular ones. After 45 days, both matrices were resorbed and morphologically normal myofibers, with reduction of cell infiltration, were observed.

CONCLUSIONS

These results demonstrated that xenogeneic placental ECM, implanted heterotopically (representing a biologically critical and challenging microenvironment), induced local inflammatory reactions similar to the allogeneic muscle ECM, implanted orthotopically. Thus, placenta-derived extracellular matrix must be further explored in regenerative medicine.

Uterine Tissue Engineering: Where We Stand and the Challenges Ahead

Tissue engineering is an innovative approach to develop allogeneic tissues and organs. The uterus is a very sensitive and complex organ, which requires refined techniques to properly regenerate and even, to rebuild itself. Many therapies were developed in 20th century to solve reproductive issues related to uterus failure and, more recently, tissue engineering techniques provided a significant evolution in this issue. Herein we aim to provide a broad overview and highlights of the general concepts involved in bioengineering to reconstruct the uterus and its tissues, focusing on strategies for tissue repair, production of uterine scaffolds, biomaterials and reproductive animal models, highlighting the most recent and effective tissue engineering protocols in literature and their application in regenerative medicine. In addition, we provide a discussion about what was achieved in uterine tissue engineering, the main limitations, the challenges to overcome and future perspectives in this research field.

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.

Wistar rat dermis recellularization

Skin lesions are normal to all species, regardless of gender or age. The skin, the largest organ of the body, has function as a primary barrier to the chemical, physical and biological aggressions of the environment. In animals, these lesions may be due to fights and/or predations, also as in humans, there is a very common cause of dermal lesions that are caused by burns and carcinomas. Looking for new techniques of tissue bioengineering, studies have been shown promising results for formulations of acellular biological scaffolds from tissue decellularization for the reconstitution of these lesions. The decellularization has its proof by a varied range of tests such as scanning electron microscopy and residual genomic DNA tests. Subsequently the tissue can go through the process of recellularization using cells of interest, even the animal that will receive this tissue, reducing the risks of rejection and improving the response to tissue transplantation. Thus, this manuscript aimed at the decellularization of the tissue with the use of chemical and physical means followed by sterilization and the establishment of a protocol for the recellularization of a decellularized scaffold from the Wistar rat dermis using murine fibroblasts and mesenchymal stem cells from canine adipose tissue for 7 days. After efficacy tests, the tissue recellularization were confirmed by immunofluorescence assays and scanning electron microscopy where the adherence of the cells in the biological scaffold was observed.

Bovine Decellularized Amniotic Membrane: Extracellular Matrix as Scaffold for Mammalian Skin

Decellularized membranes (DM) were obtained from bovine amniotic membranes (BAM) using four different decellularization protocols, based on physical, chemical, and mechanical treatment. The new material was used as a biological scaffold for in vitro skin cell culture. The DM were characterized using hematoxylin-eosin assay, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR-ATR), and differential scanning calorimetry (DSC). The in vitro cytotoxicity of DM was evaluated using MTT. The efficacy of decellularization process was assessed through DNA quantification and electrophoresis. All the used protocols showed a high effectiveness in terms of elimination of native cells, confirmed by DNA extraction and quantification, electrophoresis, and SEM, although protocol IV removes the cellular contents and preserve the native extracellular matrix (ECM) architecture which it can be considered as the most effective in terms of decellularization. FTIR-ATR and DSC on the other hand, revealed the effects of decellularization on the biochemical composition of the matrices. There was no cytotoxicity and the biological matrices obtained were a source of collagen for recellularization. The matrices of protocols I, II, and III were degraded at day 21 of cell culture, forming a gel. The biocompatibility in vitro was demonstrated; hence these matrices may be deemed as potential scaffold for epithelial tissue regeneration.

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.

Applications of mesenchymal stem cell technology in bovine species

Mesenchymal stem cells (MSCs) have received a great deal of attention over the past 20 years mainly because of the results that showed regeneration potential and plasticity that were much stronger than expected in prior decades. Recent findings in this field have contributed to progress in the establishment of cell differentiation methods, which have made stem cell therapy more clinically attractive. In addition, MSCs are easy to isolate and have anti-inflammatory and angiogenic capabilities. The use of stem cell therapy is currently supported by scientific literature in the treatment of several animal health conditions. MSC may be administered for autologous or allogenic therapy following either a fresh isolation or a thawing of a previously frozen culture. Despite the fact that MSCs have been widely used for the treatment of companion and sport animals, little is known about their clinical and biotechnological potential in the economically relevant livestock industry. This review focuses on describing the key characteristics of potential applications of MSC therapy in livestock production and explores the themes such as the concept, culture, and characterization of mesenchymal stem cells; bovine mesenchymal stem cell isolation; applications and perspectives on commercial interests and farm relevance of MSC in bovine species; and applications in translational research.

Canine Placenta Recellularized Using Yolk Sac Cells with Vascular Endothelial Growth Factor

Regenerative medicine has been growing because of the emergent need for tissues/organs for transplants and restorative surgeries. Biological scaffolds are important tools to try to solve this problem. The one used in this reserach was developed by an acellular biological scaffold from canine placenta with a rich source of cellular matrix. After decellularization, the cellular matrix demonstrated structural preservation with the presence of important functional proteins such as collagen, fibronectin, and laminin. We used cells transduced with vascular endothelial growth factor (VEGF) to recellularize this scaffold. It was succeeded by seeding the cells in nonadherent plaques in the presence of the sterelized placenta scaffold. Cells were adhered to the scaffold when analyzed by immunocytochemistry and scanning electron microscopy, both showing sprouting of yolk sac VEGF (YSVEGF) cells. This recellularized scaffold is a promissory biomaterial for repairing injured areas where neovascularization is required.