Improved ex vivo expansion of mesenchymal stem cells on solubilized acellular fetal membranes

Extracellular vesicles support increased expansion of mesenchymal stromal cells on fetal membrane-derived decellularized extracellular matrix

Decidual mesenchymal stromal cells (DMSC) were the source of extracellular vesicles (DMSC_EV). The xCELLigence real-time cell growth assay revealed increasing concentrations of EVs decreased DMSC attachment in the early growth phase but stimulated DMSC proliferation at day 7 when grown on tissue culture plastic (TCP). DMSC attachment and proliferation varied depending on the growth surface and DMSC_EV supplementation. DMSC attachment increased on decellularized and solubilized amniotic (s-dAM) whether or not EVs were added. Only Matrigel substrate increased DMSC attachment with added EVs. The addition of EVs increased DMSC proliferation only on the s-dAM substrate. DMSCs were more motile on s-dAM and decellularized and solubilized chorionic (s-dCM) membranes following EV addition. The osteogenic potential of DMSCs was improved on s-dAM substrates when supplanted with EVs. Finally, the levels of reactive oxygen species in DMSCs varied depending on the substrate but not on added EVs. We show that the addition of in vitro EVs isolated from the source being expanded (i.e., DMSCs) and the presence of ECM improve DMSC behaviours during ex vivo expansion. The inclusion of two key components of the MSC niche, EVs and ECM, benefitted the ex vivo expansion of MSCs. Added in vitro EVs increased the proliferation of DMSCs when grown on s-dAM but not on s-dCM, whereas they improved DMSC mobility on both surfaces. Testing different ECMs could be used to promote specific desired characteristics of DMSCs, and different combinations of EVs and ECM may enhance desirable MSC characteristics for specific therapeutic settings.

Beyond transplants: current and future therapeutic potential of amniotic membrane extract (AME) in ophthalmology

There is no established consensus or standardized method for the preparation of amniotic membrane extract (AME). Consequently, various preparation, preservation, and sterilization techniques have been employed. To obtain AME rich in bioactive components with high therapeutic efficacy, each step of the preparation process is of critical importance. The appropriate procurement of the amniotic membrane minimizes the risk of infection transmission and reduces inter- and intra-donor variability. For the subsequent extraction process, different approaches are utilized due to factors such as laboratory infrastructure variability and the lack of a standardized method. Although lyophilization has recently emerged as a prominent method for the long-term preservation of AME, further investigation is required to assess its impact on the biochemical composition and clinical efficacy of the membrane. In ophthalmology, in vitro, in vivo, and clinical studies indicate that AME supports corneal epithelial regeneration, suppresses inflammation, and is a well-tolerated therapeutic agent. Consequently, further studies are still needed to enhance the effective release of therapeutic components from the amniotic membrane, improve the quality and consistency of AME, and preserve its content over an extended period. Thus, the clinical application of AME-derived products in the form of eye drops will become more widespread in the future.

Advances and impact of human amniotic membrane and human amniotic-based materials in wound healing application

Wound healing is a complicated process, especially when surgical, traumatic, burn, or pathological injury occurs, which requires different kinds of dressing covers including hydrogels, hydrocolloids, alginates foams and films for treatment. The human amniotic membrane (hAM) is a biodegradable extracellular matrix with unique and tailorable physicochemical and biological properties, generated by the membrane itself or other cells that are located on the membrane surface. It is noted as a promising aid for wound healing and tissue regeneration due to the release of growth factors and cytokines, and its antibacterial and immunosuppressive properties. Moreover, hAM has optimal physical, biological, and mechanical properties, which makes it a much better option as a regenerative skin treatment than existing alternative materials. In addition, this layer has a structure with different layers and cells with different functions, which act as a regenerative geometry and reservoir of bioactive substances and cells for wound healing. In the present work, the structural and biological features of hAM are introduced as well as the application of this layer in different forms of composites to enhance wound healing. Future studies are recommended to detect possible further functionalization to enhance the hAM effectiveness on wound healing.

Tailored environments for directed mesenchymal stromal cell proliferation and differentiation using decellularized extracellular matrices in conjunction with substrate modulus

Decellularised extracellular matrix (dECM) produced by mesenchymal stromal cells (MSCs) is a promising biomaterial for improving the ex vivo expansion of MSCs. The dECMs are often deposited on high modulus surfaces such as tissue culture plastic or glass, and subsequent differentiation assays often bias towards osteogenesis. We tested the hypothesis that dECM deposited on substrates of varying modulus will produce cell culture environments that are tailored to promote the proliferation and/or lineage-specific differentiation of MSCs. dECM was produced on type I collagen-functionalised polyacrylamide hydrogels with discrete moduli (∼4, 10, and 40 kPa) or in a linear gradient of modulus that spans the same range, and the substrates were used as culture surfaces for MSCs. Fluorescence spectroscopy and mass spectrometry characterization revealed structural compositional changes in the dECM as a function of substrate modulus. Softer substrates (4 kPa) with dECM supported the largest number of MSCs after 7 days (∼1.6-fold increase compared to glass). Additionally, osteogenic differentiation was greatest on high modulus substrates (40 kPa and glass) with dECM. Nuclear translocation of YAP1 was observed on all surfaces with a modulus of 10 kPa or greater and may be a driver for the increased osteogenesis on the high modulus surfaces. These data demonstrate that dECM technology can be integrated with environmental parameters such as substrate modulus to improve/tailor MSC proliferation and differentiation during ex vivo culture. These results have potential impact in the improved expansion of MSCs for tailored therapeutic applications and in the development of advanced tissue engineering scaffolds. STATEMENT OF SIGNIFICANCE: Mesenchymal stromal cells (MSCs) are extensively used in tissue engineering and regenerative medicine due to their ability to proliferate, differentiate, and modulate the immune environment. Controlling MSC behavior is critical for advances in the field. Decellularised extracellular matrix (dECM) can maintain MSC properties in culture, increase their proliferation rate and capacity, and enhance their stimulated differentiation. Substrate stiffness is another key driver of cell function, and previous reports have primarily looked at dECM deposition and function on stiff substrates such as glass. Herein, we produce dECM on substrates of varying stiffness to create tailored environments that enhance desired MSC properties such as proliferation and differentiation. Additionally, we complete mechanistic studies including quantitative mass spec of the ECM to understand the biological function.

Advances, challenges, and future directions in the clinical translation of ECM biomaterials for regenerative medicine applications

Extracellular Matrix (ECM) scaffolds and biomaterials have been widely used for decades across a variety of diverse clinical applications and have been implanted in millions of patients worldwide. ECM-based biomaterials have been especially successful in soft tissue repair applications but their utility in other clinical applications such as for regeneration of bone or neural tissue is less well understood. The beneficial healing outcome with the use of ECM biomaterials is the result of their biocompatibility, their biophysical properties and their ability to modify cell behavior after injury. As a consequence of successful clinical outcomes, there has been motivation for the development of next-generation formulations of ECM materials ranging from hydrogels, bioinks, powders, to whole organ or tissue scaffolds. The continued development of novel ECM formulations as well as active research interest in these materials ensures a wealth of possibilities for future clinical translation and innovation in regenerative medicine. The clinical translation of next generation formulations ECM scaffolds faces predictable challenges such as manufacturing, manageable regulatory pathways, surgical implantation, and the cost required to address these challenges. The current status of ECM-based biomaterials, including clinical translation, novel formulations and therapies currently under development, and the challenges that limit clinical translation of ECM biomaterials are reviewed herein.

Human Bone Marrow-Derived Mesenchymal Stem Cell Applications in Neurodegenerative Disease Treatment and Integrated Omics Analysis for Successful Stem Cell Therapy

Neurodegenerative diseases (NDDs), which are chronic and progressive diseases, are a growing health concern. Among the therapeutic methods, stem-cell-based therapy is an attractive approach to NDD treatment owing to stem cells' characteristics such as their angiogenic ability, anti-inflammatory, paracrine, and anti-apoptotic effects, and homing ability to the damaged brain region. Human bone-marrow-derived mesenchymal stem cells (hBM-MSCs) are attractive NDD therapeutic agents owing to their widespread availability, easy attainability and in vitro manipulation and the lack of ethical issues. Ex vivo hBM-MSC expansion before transplantation is essential because of the low cell numbers in bone marrow aspirates. However, hBM-MSC quality decreases over time after detachment from culture dishes, and the ability of hBM-MSCs to differentiate after detachment from culture dishes remains poorly understood. Conventional analysis of hBM-MSCs characteristics before transplantation into the brain has several limitations. However, omics analyses provide more comprehensive molecular profiling of multifactorial biological systems. Omics and machine learning approaches can handle big data and provide more detailed characterization of hBM-MSCs. Here, we provide a brief review on the application of hBM-MSCs in the treatment of NDDs and an overview of integrated omics analysis of the quality and differentiation ability of hBM-MSCs detached from culture dishes for successful stem cell therapy.

Mesenchymal Stem/Stromal Cells and Their Role in Oxidative Stress Associated with Preeclampsia

Preeclampsia (PE) is a serious medically important disorder of human pregnancy, which features de novo pregnancy-induced hypertension and proteinuria. The severe form of PE can progress to eclampsia, a convulsive, life-threatening condition. When placental growth and perfusion are abnormal, the placenta experiences oxidative stress and subsequently secretes abnormal amounts of certain pro-angiogenic factors (eg, PlGF) as well as anti-angiogenic factors (eg, sFlt-1) that enter the maternal circulation. The net effect is damage to the maternal vascular endothelium, which subsequently manifests as the clinical features of PE. Other than delivery of the fetus and placenta, curative treatments for PE have not yet been forthcoming, which reflects the complexity of the clinical syndrome. A major source of reactive oxygen species that contributes to the widespread maternal vascular endothelium damage is the PE-affected decidua. The role of decidua-derived mesenchymal stem/stromal cells (MSC) in normotensive and pathological placenta development is poorly understood. The ability to respond to an environment of oxidative damage is a "universal property" of MSC but the biological mechanisms that MSC employ in response to oxidative stress are compromised in PE. In this review, we discuss how MSC respond to oxidative stress in normotensive and pathological conditions. We also consider the possibility of manipulating the oxidative stress response of abnormal MSC as a therapeutic strategy to treat preeclampsia.

Improvement of Mesenchymal Stromal Cell Proliferation and Differentiation via Decellularized Extracellular Matrix on Substrates With a Range of Surface Chemistries

Decellularized extracellular matrix (dECM) deposited by mesenchymal stromal cells (MSCs) has emerged as a promising substrate for improved expansion of MSCs. To date, essentially all studies that have produced dECM for MSC expansion have done so on tissue culture plastic or glass. However, substrate surface chemistry has a profound impact on the adsorption of proteins that mediate cell-material interactions, and different surface chemistries can cause changes in cell behavior, ECM deposition, and the in vivo response to a material. This study tested the hypothesis that substrate surface chemistry impacts the deposition of ECM and its subsequent bioactivity. This hypothesis was tested by producing glass surfaces with various surface chemistries (amine, carboxylic acid, propyl, and octyl groups) using silane chemistry. ECM was deposited by an immortalized MSC line, decellularized, and characterized through SDS-PAGE and immunofluorescence microscopy. No significant difference was observed in dECM composition or microarchitecture on the different surfaces. The decellularized surfaces were seeded with primary MSCs and their proliferation and differentiation were assessed. The presence of dECM improved the proliferation of primary MSCs by ~100% in comparison to surface chemistry controls. Additionally, the adipogenesis increased by 50–90% on all dECM surfaces in comparison to surface chemistry controls, and the osteogenesis increased by ~50% on the octyl-modified surfaces when dECM was present. However, no statistically significant differences were observed within the set of dECM surfaces or control surfaces. These results support the null hypothesis, meaning surface chemistry (over the range tested in this work) is not a key regulator of the composition or bioactivity of MSC-derived dECM. These results are significant because they provide an important insight into regenerative engineering technologies. Specifically, the utilization of dECM in stem cell manufacturing and tissue engineering applications would require the dECM to be produced on a wide variety of substrates. This work indicates that it can be produced on materials with a range of surface chemistries without undesired changes in the bioactivity of the dECM.

Strategies to Improve the Quality and Freshness of Human Bone Marrow-Derived Mesenchymal Stem Cells for Neurological Diseases

Human bone marrow-derived mesenchymal stem cells (hBM-MSCs) have been studied for their application to manage various neurological diseases, owing to their anti-inflammatory, immunomodulatory, paracrine, and antiapoptotic ability, as well as their homing capacity to specific regions of brain injury. Among mesenchymal stem cells, such as BM-MSCs, adipose-derived MSCs, and umbilical cord MSCs, BM-MSCs have many merits as cell therapeutic agents based on their widespread availability and relatively easy attainability and in vitro handling. For stem cell-based therapy with BM-MSCs, it is essential to perform ex vivo expansion as low numbers of MSCs are obtained in bone marrow aspirates. Depending on timing, before hBM-MSC transplantation into patients, after detaching them from the culture dish, cell viability, deformability, cell size, and membrane fluidity are decreased, whereas reactive oxygen species generation, lipid peroxidation, and cytosolic vacuoles are increased. Thus, the quality and freshness of hBM-MSCs decrease over time after detachment from the culture dish. Especially, for neurological disease cell therapy, the deformability of BM-MSCs is particularly important in the brain for the development of microvessels. As studies on the traditional characteristics of hBM-MSCs before transplantation into the brain are very limited, omics and machine learning approaches are needed to evaluate cell conditions with indepth and comprehensive analyses. Here, we provide an overview of hBM-MSCs, the application of these cells to various neurological diseases, and improvements in their quality and freshness based on integrated omics after detachment from the culture dish for successful cell therapy.

Comprehensive Comparison of Amnion Stromal Cells and Chorion Stromal Cells by RNA-Seq

Mesenchymal stromal cells derived from the fetal placenta, composed of an amnion membrane, chorion membrane, and umbilical cord, have emerged as promising sources for regenerative medicine. Here, we used next-generation sequencing technology to comprehensively compare amniotic stromal cells (ASCs) with chorionic stromal cells (CSCs) at the molecular and signaling levels. Principal component analysis showed a clear dichotomy of gene expression profiles between ASCs and CSCs. Unsupervised hierarchical clustering confirmed that the biological repeats of ASCs and CSCs were able to respectively group together. Supervised analysis identified differentially expressed genes, such as LMO3, HOXA11, and HOXA13, and differentially expressed isoforms, such as CXCL6 and HGF. Gene Ontology (GO) analysis showed that the GO terms of the extracellular matrix, angiogenesis, and cell adhesion were significantly enriched in CSCs. We further explored the factors associated with inflammation and angiogenesis using a multiplex assay. In comparison with ASCs, CSCs secreted higher levels of angiogenic factors, including angiogenin, VEGFA, HGF, and bFGF. The results of a tube formation assay proved that CSCs exhibited a strong angiogenic function. However, ASCs secreted two-fold more of an anti-inflammatory factor, TSG-6, than CSCs. In conclusion, our study demonstrated the differential gene expression patterns between ASCs and CSCs. CSCs have superior angiogenic potential, whereas ASCs exhibit increased anti-inflammatory properties.

A Review on Modifications of Amniotic Membrane for Biomedical Applications

The amniotic membrane (AM) is the innermost layer of the fetal placenta, which surrounds and protects the fetus. Its unique structure, in addition to its physical and biological properties, makes it a useful substance in many applications related to regenerative medicine. The use of this fantastic substance with a century-old history has produced remarkable results in vivo, in vitro, and even in clinical studies. While the intact or preserved AM is widely used for these purposes, the addition of further modifications to AM can be considered as a relatively new subject in its applications. These modifications are applied to improve AM properties, ease of handling, and durability. Here, we will discuss the cases in which AM has undergone additional modifications besides the required processes for sterilization and preservation. In this article, we have categorized these modifications and discussed their applications and results.

Deconstructing, Replicating, and Engineering Tissue Microenvironment for Stem Cell Differentiation

One of the most crucial components of regenerative medicine is the controlled differentiation of embryonic or adult stem cells into the desired cell lineage. Although most of the reported protocols of stem cell differentiation involve the use of soluble growth factors, it is increasingly evident that stem cells also undergo differentiation when cultured in the appropriate microenvironment. When cultured in decellularized tissues, for instance, stem cells can recapitulate the morphogenesis and functional specialization of differentiated cell types with speed and efficiency that often surpass the traditional growth factor-driven protocols. This suggests that the tissue microenvironment (TME) provides stem cells with a holistic "instructive niche" that harbors signals for cellular reprogramming. The translation of this into medical applications requires the decoding of these signals, but this has been hampered by the complexity of TME. This problem is often addressed by a reductionist approach, in which cells are exposed to substrates decorated with simple, empirically designed geometries, textures, and chemical compositions ("bottom-up" approach). Although these studies are invaluable in revealing the basic principles of mechanotransduction mechanisms, their physiological relevance is often uncertain. This review examines the recent progress of an alternative, "top-down" approach, in which the TME is treated as a holistic biological entity. This approach is made possible by recent advances in systems biology and fabrication technologies that enable the isolation, characterization, and reconstitution of TME. It is hoped that these new techniques will elucidate the nature of niche signals so that they can be extracted, replicated, and controlled. This review summarizes these emerging techniques and how the data they generated are changing our view on TME. Impact statement This review summarizes the current state of art of the understanding of instructive niche in the field of tissue microenvironment. Not only did we survey the use of different biochemical preparations as stimuli of stem cell differentiation and summarize the recent effort in dissecting the biochemical composition of these preparations, through the application of extracellular matrix (ECM) arrays and proteomics, but we also introduce the use of open-source, high-content immunohistochemistry projects in contributing to the understanding of tissue-specific composition of ECM. We believe this review would be highly useful for our peer researching in the same field. "Mr. Tulkinghorn is always the same… so oddly out of place and yet so perfectly at home." -Charles Dickens, Bleak House.

Applications of decellularized materials in tissue engineering: advantages, drawbacks and current improvements, and future perspectives

Decellularized materials (DMs) are attracting more and more attention in tissue engineering because of their many unique advantages, and they could be further improved in some aspects through various means.

Decellularized neonatal cardiac extracellular matrix prevents widespread ventricular remodeling in adult mammals after myocardial infarction

Heart disease remains a leading killer in western society and irreversibly impacts the lives of millions of patients annually. While adult mammals do not possess the ability to regenerate functional cardiac tissue, neonatal mammals are capable of robust cardiomyocyte proliferation and regeneration within a week of birth. Given this change in regenerative function through development, the extracellular matrix (ECM) from adult tissues may not be conducive to promoting cardiac regeneration, although conventional ECM therapies rely exclusively on adult-derived tissues. Therefore the potential of ECM derived from neonatal mouse hearts (nmECM) to prevent adverse ventricular remodeling in adults was investigated using an in vivo model of acute myocardial infarction (MI). Following a single administration of nmECM, we observed a significant improvement in heart function while adult heart-derived ECM (amECM) did not improve these parameters. Treatment with nmECM limits scar expansion in the left ventricle and promotes revascularization of the injured region. Furthermore, nmECM induced expression of the ErbB2 receptor, simulating a neonatal-like environment and promoting neuregulin-1 associated cardiac function. Inhibition of the ErbB2 receptor effectively prevents these actions, suggesting its role in the context of nmECM as a therapy. This study shows the potential of a neonatal-derived biological material in vivo, diverting from the conventional use of adult-derived ECM therapies in research and the clinic. STATEMENT OF SIGNIFICANCE: The of use extracellular matrix biomaterials to aid tissue repair has been previously reported in many forms of injury. The majority of ECM studies to date utilized ECM derived from adult tissues that are not able to fully regenerate functional tissue. In contrast, this study tests the ability of ECM derived from a regenerative organ, the neonatal heart, to stimulate functional cardiac repair after MI. This study is the first to test its potential in vivo. Our results indicate that extracellular factors present in the neonatal environment can be used to alter the healing response in adults, and we have identified the role of ErbB2 in neonatal ECM-based cardiac repair.