Mesenchymal progenitor cells derived from chorionic villi of human placenta for cartilage tissue engineering

The Chondrogenic Potential of First-Trimester and Term Placental Mesenchymal Stem/Stromal Cells

OBJECTIVES

Mesenchymal stem/stromal cells (MSCs) are a well-established cell source for cartilage engineering, but challenges remain as differentiation often results in chondrocyte hypertrophy. Chondrogenic potential also varies with MSC source and donor age. We assessed the chondrogenic potential of first-trimester and term placental MSCs and compared their response to commonly used bone marrow MSCs (BM-MSCs).

DESIGN

MSCs were isolated from first-trimester and term placentae. BM-MSCs were commercially obtained. Chondrogenesis was induced by micromass culture in commercial chondrogenic media for 7, 14, or 21 days. Pellets were assessed for glycosaminoglycan (GAG) content, and types I, II, and X collagen. Gene expression was profiled using Qiagen RT2 human MSC arrays.

RESULTS

At day 0, first-trimester and term MSCs expression levels of many chondrogenic genes to BM-MSC after 21 days of culture. Only first trimester MSCs showed significant changes in chondrogenic gene expression during induction compared to day 0 undifferentiated MSCs (greater BMP4, KAT2B, and reduced GDF6 expression). Additionally, first-trimester MSCs showed significantly greater expression of ABCB1 (at days 14 and 21) and BMP4 (at days 7, 14, 21) compared with term MSCs. Both first-trimester and term pellets showed increased GAG content over time and term MSCs had significantly GAG greater compared with BM-MSCs at days 7 and 14. Type II collagen was present in all pellets but unlike BM-MSCs, type I collagen was not observed in first-trimester or term MSC pellets.

CONCLUSIONS

These data highlight differences in BM-MSC and placental MSC chondrogenesis and demonstrate that placental MSCs may be an alternative cell source.

IGF-1-Expressing Placenta-Derived Mesenchymal Stem Cells Promote Scalding Wound Healing

BACKGROUND

Stem cell-based regenerative therapy is a novel approach to severe damaged skin. Perinatal tissues such as placenta are considered as promising alternatives. The present study aimed to investigate the effect of insulin-like growth factor-1 (IGF-1)-expressing placenta-derived mesenchymal stem cells (hPMSCs) on healing of burn wounds.

MATERIALS AND METHODS

hPMSCs were isolated from human placenta, and IGF-1 was transducted into hPMSCs via lentivirus. Flow cytometry and MTT assay were performed to assess cell apoptosis and viability, respectively. Immunostaining of CK19 and ki67 was for evaluating epithelial differentiation ability and cell proliferation. For in vivo studies, we established a mouse model of scalding and performed local administration of IGF-1-expressing hPMSCs via subcutaneous injection. Wound histology was analyzed with H&E staining. The expression of fibrogenic cytokines was detected by western blot. The production of pro-inflammatory factors was measured by ELISA.

RESULTS

Overexpression of IGF-1 promoted cell proliferation and epithelial differentiation of hPMSCs in vitro and in vivo. Mice with burn injury displayed increased wound contraction and healing rates following treatment with IGF-1-expressing hPMSCs. There was less inflammatory infiltration and reduced collagen disposition in the presence of IGF-1 at the wound site. Administration of IGF-1-expressing hPMSCs suppressed inflammation by decreasing the levels of pro-inflammatory cytokines including tumor necrosis factor-α, interleukin-1β, and interleukin-6. Besides, IGF-1 increased VEGF expression, and decreased TGF-β1, collagen I and collagen III expressions in vivo.

CONCLUSIONS

IGF-1-expressing PMSCs promotes cell proliferation and epithelial differentiation, inhibits inflammation and collagen deposition, and thus contributes to wound healing.

Allogenic Use of Human Placenta-Derived Stromal Cells as a Highly Active Subtype of Mesenchymal Stromal Cells for Cell-Based Therapies

The application of mesenchymal stromal cells (MSCs) from different sources, including bone marrow (BM, bmMSCs), adipose tissue (atMSCs), and human term placenta (hPSCs) has been proposed for various clinical purposes. Accumulated evidence suggests that the activity of the different MSCs is indirect and associated with paracrine release of pro-regenerative and anti-inflammatory factors. A major limitation of bmMSCs-based treatment for autologous application is the limited yield of cells harvested from BM and the invasiveness of the procedure. Similar effects of autologous and allogeneic MSCs isolated from various other tissues were reported. The easily available fresh human placenta seems to represent a preferred source for harvesting abundant numbers of human hPSCs for allogenic use. Cells derived from the neonate tissues of the placenta (f-hPSC) can undergo extended expansion with a low risk of senescence. The low expression of HLA class I and II on f-hPSCs reduces the risk of rejection in allogeneic or xenogeneic applications in normal immunocompetent hosts. The main advantage of hPSCs-based therapies seems to lie in the secretion of a wide range of pro-regenerative and anti-inflammatory factors. This renders hPSCs as a very competent cell for therapy in humans or animal models. This review summarizes the therapeutic potential of allogeneic applications of f-hPSCs, with reference to their indirect pro-regenerative and anti-inflammatory effects and discusses clinical feasibility studies.

Current Status and Future Prospects of Perinatal Stem Cells

The placenta is a temporary organ that is discarded after birth and is one of the most promising sources of various cells and tissues for use in regenerative medicine and tissue engineering, both in experimental and clinical settings. The placenta has unique, intrinsic features because it plays many roles during gestation: it is formed by cells from two individuals (mother and fetus), contributes to the development and growth of an allogeneic fetus, and has two independent and interacting circulatory systems. Different stem and progenitor cell types can be isolated from the different perinatal tissues making them particularly interesting candidates for use in cell therapy and regenerative medicine. The primary source of perinatal stem cells is cord blood. Cord blood has been a well-known source of hematopoietic stem/progenitor cells since 1974. Biobanked cord blood has been used to treat different hematological and immunological disorders for over 30 years. Other perinatal tissues that are routinely discarded as medical waste contain non-hematopoietic cells with potential therapeutic value. Indeed, in advanced perinatal cell therapy trials, mesenchymal stromal cells are the most commonly used. Here, we review one by one the different perinatal tissues and the different perinatal stem cells isolated with their phenotypical characteristics and the preclinical uses of these cells in numerous pathologies. An overview of clinical applications of perinatal derived cells is also described with special emphasis on the clinical trials being carried out to treat COVID19 pneumonia. Furthermore, we describe the use of new technologies in the field of perinatal stem cells and the future directions and challenges of this fascinating and rapidly progressing field of perinatal cells and regenerative medicine.

An Overview on Mesenchymal Stem Cells Derived from Extraembryonic Tissues: Supplement Sources and Isolation Methods

Purpose

The main aim of this review was to provide an updated comprehensive report regarding isolation methods of MSCs from human extra embryonic tissues, including cord blood, amniotic fluid, and different parts of the placenta and umbilical cord, with respect to the efficacy of these methods.

Results

Extra embryonic tissues are the most available source for harvesting of mesenchymal stem cells (MSCs). They make a large number of cells accessible using non-invasive methods of isolation and the least immune-rejection reactions. A successful culture of primary cells requires obtaining a maximum yield of functional and viable cells from the tissues. In addition, there are many reports associated with their differentiation into various kinds of cells, and there are some clinical trials regarding their utilization for patients.

Conclusion

Currently, cord blood-MSCs have been tested for cartilage and lung diseases. Umbilical cord-MSCs were tested for liver and neural disorders. However, these MSCs can be isolated, expanded, and cryopreserved in a cell bank for patients in need.

Comparative separation methods and biological characteristics of human placental and umbilical cord mesenchymal stem cells in serum-free culture conditions

Background

Mesenchymal stem cells (MSCs) are considered to be an effective tool for regenerative medicine with promising applications for clinical therapy. However, incongruent data has been reported partially owing to their functional heterogeneity. To provide sufficient and suitable clinical seed cells derived from the placenta for MSC therapy, we compared the various current isolation methods, as well as the biological characteristics, of different human placenta mesenchymal stem cells (hPMSCs).

Methods

We selected placentas from 35 informed donors and exploited three commonly used methods. MSCs were isolated from different parts of placental tissue including umbilical cord (UC), amniotic membrane (AM), chorionic membrane (CM), chorionic villi (CV), and deciduae (DC). The appropriate isolation methods for each type of hPMSCs were first assessed. The resulting five MSC types from the same individuals were identified based on their surface marker expression, proliferation capacity, transcriptome, differentiation, multipotency and karyotype.

Results

All three methods successfully isolated the five hPMSC types from placental tissues. However, the UC-MSCs were most effectively separated via the tissue explant method, while the enzymatic digestion method was found to be more suitable for separating CV-MSCs, owing to its higher output efficiency compared to the other methods. Alternatively, the perfusion method was complicated and exhibited the lowest efficiency for cell isolation and uniformity. Furthermore, we determined that UC-MSCs and CV-MSCs express a higher level of paracrine cytokines and display much stronger proliferative capacity as well as superior extraction efficiency. Finally, karyotype analysis revealed that DC-MSCs are derived from the mother, while the other cell types are derived from the fetus. Moreover, the different hPMSCs exhibited unique gene expression profiles, which may prove advantageous in treatment of a broad range of diseases.

Conclusions

hPMSCs from different sources are similar yet also unique. Our results describe the biological characteristics of five hPMSCs and provide insights to aide in the selection process of candidates for MSCs treatment. Overall, UC- and CV-MSCs appear to be ideal sources of primary MSCs for clinical treatment and future research.

Role of Insulin-like Growth Factor 1 Receptor Signaling in Stem Cell Stemness and Therapeutic Efficacy

Evidence has emerged that stem cells represent a promising therapeutic tool for tissue engineering and regenerative medicine. Thus, identifying functional markers for selecting stem cells capable of superior self-renewal and pluripotency (or multipotency) and maintaining stem cell identity under appropriate culture conditions are critical for guiding the use of stem cells toward clinical applications. Many investigations have implicated the insulin-like growth factor 1 receptor (IGF1R) signaling in maintenance of stem cell characteristics and enhancement of stem cell therapy efficacy. IGF1R-expressing stem cells display robust pluripotent or multipotent properties. In this review, we summarize the essential roles of IGF1R signaling in self-renewal, pluripotency (or multipotency), and therapeutic efficacy of stem cells, including human embryonic stem cells, neural stem cells, cardiac stem cells, bone marrow mesenchymal stem cells, placental mesenchymal stem cells, and dental pulp mesenchymal stem cells. Modifying IGF1R signaling may thus provide potential strategies for maintaining stem cell properties and improving stem-cell-based therapeutic applications.

Cardiac Restoration Stemming From the Placenta Tree: Insights From Fetal and Perinatal Cell Biology

Efficient cardiac repair and ultimate regeneration still represents one of the main challenges of modern medicine. Indeed, cardiovascular disease can derive from independent conditions upsetting heart structure and performance: myocardial ischemia and infarction (MI), pharmacological cardiotoxicity, and congenital heart defects, just to name a few. All these disorders have profound consequences on cardiac tissue, inducing the onset of heart failure over time. Since the cure is currently represented by heart transplantation, which is extremely difficult due to the shortage of donors, much effort is being dedicated to developing innovative therapeutic strategies based on stem cell exploitation. Among the broad scenario of stem/progenitor cell subpopulations, fetal and perinatal sources, namely amniotic fluid and term placenta, have gained interest due to their peculiar regenerative capacity, high self-renewal capability, and ease of collection from clinical waste material. In this review, we will provide the state-of-the-art on fetal perinatal stem cells for cardiac repair and regeneration. We will discuss different pathological conditions and the main therapeutic strategies proposed, including cell transplantation, putative paracrine therapy, reprogramming, and tissue engineering approaches.

Isolation and Characterization of Mesenchymal Stem/Stromal Cells Derived from Human Third Trimester Placental Chorionic Villi and Decidua Basalis

The decidua basalis and placental chorionic villi are critical components of maternal-fetal interface, which plays a critical role in normal placental development. Failure to form a proper maternal-fetal interface is associated with clinically important placental pathologies including preeclampsia and fetal growth restriction. Placental trophoblast cells are well known for their critical roles in establishing the maternal-fetal interface; however accumulating evidence also implicates mesenchymal stem/stromal cells that envelop the maternal and fetal blood vessels as playing an important role in the formation and efficient functioning of the interface. Moreover, recent studies associate abnormal mesenchymal stem/stromal cell function in the development of preeclampsia. Further research is needed to fully understand the role that these cells play in this clinically important placental pathology.The intimate relationship between maternal and fetal tissues at the interface poses significant problems in the enrichment of decidua basalis and chorionic villous mesenchymal stem/stromal cells without significant cross-contamination. The protocols described below for the enrichment and characterization of mesenchymal stem/stromal cells from the maternal-fetal interface produce highly enriched cells that conform to international standards and show minimal cross-contamination.

Comparison of Human Amniotic, Chorionic, and Umbilical Cord Multipotent Mesenchymal Stem Cells Regarding Their Capacity for Differentiation Toward Female Germ Cells

Placenta harbors a plentiful source of various cells with stem cells or stem-like cell properties, which can be used in therapeutic procedures and research. Mesenchymal stem cells (MSCs) have attracted much attention due to their specific differentiation potential and tolerogenic properties. MSCs have been isolated from different parts of placenta; however, in this study, we isolated MSCs from amnion and chorion membrane, as well as umbilical cord (Wharton's jelly [WJ]) and compared their capacity regarding differentiation toward female germ cells under influence of 10 ng/mL BMP4. All placenta samples were collected from delivering mothers by normal cesarean section and cells were isolated by different methods. Results showed that all isolated cells were mostly positive for the MSC markers CD73, CD166, and CD105, and minimally reacted with CD34 and CD45 (hematopoietic markers). After differentiation induction using third passage cultured cells, immunocytochemistry staining showed that cells were positive for germline cell-related genes Ssea4, Oct4, and Ddx4, and oocyte-related gene Gdf9. RT-qPCR results indicated that human chorion MSCs (hCMSCs) had a greater potential to be differentiated into female germline cells. Moreover, the results of this study indicate that human umbilical cord MSCs originated from either male or female umbilical cord have the same differentiation potential into female germline cells. We recommend that for presumptive application of MSCs for infertility treatment and research, hUMSCs are best candidates due to their higher differentiation potential, ease of proliferation and expansion, and low immunogenicity.

Explant culture: An advantageous method for isolation of mesenchymal stem cells from human tissues

Mesenchymal stem cell (MSC) research progressively moves towards clinical phases. Accordingly, a wide range of different procedures were presented in the literature for MSC isolation from human tissues; however, there is not yet any close focus on the details to offer precise information for best method selection. Choosing a proper isolation method is a critical step in obtaining cells with optimal quality and yield in companion with clinical and economical considerations. In this concern, current review widely discusses advantages of omitting proteolysis step in isolation process and presence of tissue pieces in primary culture of MSCs, including removal of lytic stress on cells, reduction of in vivo to in vitro transition stress for migrated/isolated cells, reduction of price, processing time and labour, removal of viral contamination risk, and addition of supporting functions of extracellular matrix and released growth factors from tissue explant. In next sections, it provides an overall report of technical highlights and molecular events of explant culture method for isolation of MSCs from human tissues including adipose tissue, bone marrow, dental pulp, hair follicle, cornea, umbilical cord and placenta. Focusing on informative collection of molecular and methodological data about explant methods can make it easy for researchers to choose an optimal method for their experiments/clinical studies and also stimulate them to investigate and optimize more efficient procedures according to clinical and economical benefits.

The use of mesenchymal stem cells for cartilage repair and regeneration: a systematic review

BACKGROUND

The management of articular cartilage defects presents many clinical challenges due to its avascular, aneural and alymphatic nature. Bone marrow stimulation techniques, such as microfracture, are the most frequently used method in clinical practice however the resulting mixed fibrocartilage tissue which is inferior to native hyaline cartilage. Other methods have shown promise but are far from perfect. There is an unmet need and growing interest in regenerative medicine and tissue engineering to improve the outcome for patients requiring cartilage repair. Many published reviews on cartilage repair only list human clinical trials, underestimating the wealth of basic sciences and animal studies that are precursors to future research. We therefore set out to perform a systematic review of the literature to assess the translation of stem cell therapy to explore what research had been carried out at each of the stages of translation from bench-top (in vitro), animal (pre-clinical) and human studies (clinical) and assemble an evidence-based cascade for the responsible introduction of stem cell therapy for cartilage defects. This review was conducted in accordance to PRISMA guidelines using CINHAL, MEDLINE, EMBASE, Scopus and Web of Knowledge databases from 1st January 1900 to 30th June 2015. In total, there were 2880 studies identified of which 252 studies were included for analysis (100 articles for in vitro studies, 111 studies for animal studies; and 31 studies for human studies). There was a huge variance in cell source in pre-clinical studies both of terms of animal used, location of harvest (fat, marrow, blood or synovium) and allogeneicity. The use of scaffolds, growth factors, number of cell passages and number of cells used was hugely heterogeneous.

SHORT CONCLUSIONS

This review offers a comprehensive assessment of the evidence behind the translation of basic science to the clinical practice of cartilage repair. It has revealed a lack of connectivity between the in vitro, pre-clinical and human data and a patchwork quilt of synergistic evidence. Drivers for progress in this space are largely driven by patient demand, surgeon inquisition and a regulatory framework that is learning at the same pace as new developments take place.

Different characteristics of mesenchymal stem cells isolated from different layers of full term placenta

Background

The placenta is a very attractive source of mesenchymal stem cells (MSCs) for regenerative medicine due to readily availability, non-invasive acquisition, and avoidance of ethical issues. Isolating MSCs from parts of placenta tissue has obtained growing interest because they are assumed to exhibit different proliferation and differentiation potentials due to complex structures and functions of the placenta. The objective of this study was to isolate MSCs from different parts of the placenta and compare their characteristics.

Methods

Placenta was divided into amniotic epithelium (AE), amniotic membrane (AM), chorionic membrane (CM), chorionic villi (CV), chorionic trophoblast without villi (CT-V), decidua (DC), and whole placenta (Pla). Cells isolated from each layer were subjected to analyses for their morphology, proliferation ability, surface markers, and multi-lineage differentiation potential. MSCs were isolated from all placental layers and their characteristics were compared.

Findings

Surface antigen phenotype, morphology, and differentiation characteristics of cells from all layers indicated that they exhibited properties of MSCs. MSCs from different placental layers had different proliferation rates and differentiation potentials. MSCs from CM, CT-V, CV, and DC had better population doubling time and multi-lineage differentiation potentials compared to those from other layers.

Conclusions

Our results indicate that MSCs with different characteristics can be isolated from all layers of term placenta. These finding suggest that it is necessary to appropriately select MSCs from different placental layers for successful and consistent outcomes in clinical applications.

Hypoxic conditioned medium of placenta-derived mesenchymal stem cells protects against scar formation

AIMS

Scar formation after wound repair affects people's daily life. Mesenchymal stem cells were reported to have a beneficial role in attenuating the scar formation. In the present study, placenta-derived mesenchymal stem cells (PMSCs) were isolated and the effects of hypoxic conditioned medium of PMSCs on scar formation were explored.

MAIN METHODS

To evaluate the effect of hypoxia on PMSCs, proliferation of PMSCs was detected by trypan blue staining and the HIF-1α level was detected by western blot. Then in vivo scar formation assay was performed and the histopathologic changes were evaluated by HE staining and levels of TGF-β1 and collagen I were detected by quantitative real-time PCR. The IL-10 level was detected by ELISA and then migration of HFF-1 cells was detected by wound healing assay after treatment with IL-10 or IL-10 antibody.

KEY FINDINGS

Our study showed that hypoxic conditioned medium of PMSCs reduced scar formation in vivo and inhibited the proliferation and migration of skin fibroblasts in vitro. Further mechanism study showed that, the level of IL-10 was affected by hypoxia, treatment with IL-10 mimicked the function of hypoxic conditioned medium of PMSCs and inhibition of IL-10 reversed the protective role of hypoxic conditioned medium of PMSCs. Thus, hypoxic conditioned medium of PMSCs may perform the protective role against scar formation through IL-10.

SIGNIFICANCE

Our study reveals a possible mechanism of the protective effect of PMSCs against scar formation and provides evidence for the hypothesis that PMSCs may be a promising therapy for the treatment of wounds.

Stem cells: a promising source for vascular regenerative medicine

The rising and diversity of many human vascular diseases pose urgent needs for the development of novel therapeutics. Stem cell therapy represents a challenge in the medicine of the twenty-first century, an area where tissue engineering and regenerative medicine gather to provide promising treatments for a wide variety of diseases. Indeed, with their extensive regeneration potential and functional multilineage differentiation capacity, stem cells are now highlighted as promising cell sources for regenerative medicine. Their multilineage differentiation involves environmental factors such as biochemical, extracellular matrix coating, oxygen tension, and mechanical forces. In this review, we will focus on human stem cell sources and their applications in vascular regeneration. We will also discuss the different strategies used for their differentiation into both mature and functional smooth muscle and endothelial cells.

Differentiation Potential of Human Chorion-Derived Mesenchymal Stem Cells into Motor Neuron-Like Cells in Two- and Three-Dimensional Culture Systems

Many people worldwide suffer from motor neuron-related disorders such as amyotrophic lateral sclerosis and spinal cord injuries. Recently, several attempts have been made to recruit stem cells to modulate disease progression in ALS and also regenerate spinal cord injuries. Chorion-derived mesenchymal stem cells (C-MSCs), used to be discarded as postpartum medically waste product, currently represent a class of cells with self renewal property and immunomodulatory capacity. These cells are able to differentiate into mesodermal and nonmesodermal lineages such as neural cells. On the other hand, gelatin, as a simply denatured collagen, is a suitable substrate for cell adhesion and differentiation. It has been shown that electrospinning of scaffolds into fibrous structure better resembles the physiological microenvironment in comparison with two-dimensional (2D) culture system. Since there is no report on potential of human chorion-derived MSCs to differentiate into motor neuron cells in two- and three-dimensional (3D) culture systems, we set out to determine the effect of retinoic acid (RA) and sonic hedgehog (Shh) on differentiation of human C-MSCs into motor neuron-like cells cultured on tissue culture plates (2D) and electrospun nanofibrous gelatin scaffold (3D).

Early gestation chorionic villi-derived stromal cells for fetal tissue engineering

AIM: To investigate the potential for early gestation placenta-derived mesenchymal stromal cells (PMSCs) for fetal tissue engineering.

METHODS: PMSCs were isolated from early gestation chorionic villus tissue by explant culture. Chorionic villus sampling (CVS)-size tissue samples (mean = 35.93 mg) were used to test the feasibility of obtaining large cell numbers from CVS within a clinically relevant timeframe. We characterized PMSCs isolated from 6 donor placentas by flow cytometry immunophenotyping, multipotency assays, and through immunofluorescent staining. Protein secretion from PMSCs was examined using two cytokine array assays capable of probing for over 70 factors in total. Delivery vehicle compatibility of PMSCs was determined using three common scaffold systems: fibrin glue, collagen hydrogel, and biodegradable nanofibrous scaffolds made from a combination of polylactic acid (PLA) and poly(lactic-co-glycolic acid) (PLGA). Viral transduction of PMSCs was performed using a Luciferase-GFP-containing lentiviral vector and efficiency of transduction was tested by fluorescent microscopy and flow cytometry analysis.

RESULTS: We determined that an average of 2.09 × 10⁶ (SD ± 8.59 × 10⁵) PMSCs could be obtained from CVS-size tissue samples within 30 d (mean = 27 d, SD ± 2.28), indicating that therapeutic numbers of cells can be rapidly expanded from very limited masses of tissue. Immunophenotyping by flow cytometry demonstrated that PMSCs were positive for MSC markers CD105, CD90, CD73, CD44, and CD29, and were negative for hematopoietic and endothelial markers CD45, CD34, and CD31. PMSCs displayed trilineage differentiation capability, and were found to express developmental transcription factors Sox10 and Sox17 as well as neural-related structural proteins NFM, Nestin, and S100β. Cytokine arrays revealed a robust and extensive profile of PMSC-secreted cytokines and growth factors, and detected 34 factors with spot density values exceeding 10³. Detected factors had widely diverse functions that include modulation of angiogenesis and immune response, cell chemotaxis, cell proliferation, blood vessel maturation and homeostasis, modulation of insulin-like growth factor activity, neuroprotection, extracellular matrix degradation and even blood coagulation. Importantly, PMSCs were also determined to be compatible with both biological and synthetic material-based delivery vehicles such as collagen and fibrin hydrogels, and biodegradable nanofiber scaffolds made from a combination of PLA and PLGA. Finally, we demonstrated that PMSCs can be efficiently transduced (> 95%) with a Luciferase-GFP-containing lentiviral vector for future in vivo cell tracking after transplantation.

CONCLUSION: Our findings indicate that PMSCs represent a unique source of cells that can be effectively utilized for in utero cell therapy and tissue engineering.

Postpartum Women's Perspectives on the Donation of Placentas for Scientific Research in Campinas, Brazil

Little is known about public perspectives of scientific and therapeutic uses of placentas. Gaps in knowledge potentiate ethical and clinical problems regarding collection and applications. As such, this study sought to assess the perspectives of placenta donation of a sample of women. Postpartum women's perspectives on placental donation were assessed at the State University of Campinas in the Centro de Atençäo Integral a Saúde da Mulher (CAISM) maternity hospital using a cross-sectional survey (n = 384) and semi-structured interviews (n = 12). Surveys were analyzed quantitatively and interviews were analyzed qualitatively using grounded coding; results were compared. The average age of respondents was 27. Fifty-six percent had more than one child, 45% were Caucasian, 38% were mixed-race, 74% identified with a Christian faith, 52% had high school education or higher, 13% regarded the placenta as spiritually important, 72% felt that knowing what happens to the placenta after birth was somewhat or very important, 78% supported the use of the placenta in research and medicine, 59% reported that consent to collect the placenta was very or somewhat important, 78% preferred their doctor to invite donation, and only 7% preferred the researcher to invite donation. Interviews suggested women appreciate being part of research and that receiving information about studies was important to them. Informed by these results, we argue that women support scientific and therapeutic uses of placentas, want to be included in decision making, and desire information about the placenta. Placentas should not be viewed as "throwaway" organs that are poised for collection without the involvement and permission of women. Women want to be meaningfully included in research processes.

Cell-based therapies for the preterm infant

The severely preterm infant receives a multitude of life-saving interventions, many of which carry risks of serious side effects. Cell therapy is an important and promising arm of regenerative medicine that may address a number of these problems. Most forms of cellular therapy use stem/progenitor cells or stem-like cells, which have the capacity to migrate, engraft and exert anti-inflammatory effects. Although some of these cell-based therapies have made their way to clinical trials in adults, little headway has been made in the neonatal patient group. This review discusses the efficacy of cell therapy in preclinical studies to date and their potential applications to diseases that afflict many prematurely born infants. Specifically, we identify the major hurdles that must be overcome before cell therapies can be safely used in the neonatal intensive care unit.

Improvement of cardiac function by placenta-derived mesenchymal stem cells does not require permanent engraftment and is independent of the insulin signaling pathway

INTRODUCTION

The objective of this work was to evaluate the efficacy of placenta-derived mesenchymal stem cell (MSC) therapy in a mouse model of myocardial infarction (MI). Since MSCs can be obtained from two different regions of the human term placenta (chorionic plate or villi), cells obtained from both these regions were compared so that the best candidate for cell therapy could be selected.

METHODS

For the in vitro studies, chorionic plate MSCs (cp-MSCs) and chorionic villi MSCs (cv-MSCs) were extensively characterized for their genetic stability, clonogenic and differentiation potential, gene expression, and immunophenotype. For the in vivo studies, C57Bl/6 mice were submitted to MI and, after 21 days, received weekly intramyocardial injections of cp-MSCs for 3 weeks. Cells were also stably transduced with a viral construct expressing luciferase, under the control of the murine stem cell virus (MSCV) promoter, and were used in a bioluminescence assay. The expression of genes associated with the insulin signaling pathway was analyzed in the cardiac tissue from cp-MSCs and placebo groups.

RESULTS

Morphology, differentiation, immunophenotype, and proliferation were quite similar between these cells. However, cp-MSCs had a greater clonogenic potential and higher expression of genes related to cell cycle progression and genome stability. Therefore, we considered that the chorionic plate was preferable to the chorionic villi for the isolation of MSCs. Sixty days after MI, cell-treated mice had a significant increase in ejection fraction and a reduction in end-systolic volume. This improvement was not caused by a reduction in infarct size. In addition, tracking of cp-MSCs transduced with luciferase revealed that cells remained in the heart for 4 days after the first injection but that the survival period was reduced after the second and third injections. Quantitative reverse transcription-polymerase chain reaction revealed similar expression of genes involved in the insulin signaling pathway when comparing cell-treated and placebo groups.

CONCLUSIONS

Improvement of cardiac function by cp-MSCs did not require permanent engraftment and was not mediated by the insulin signaling pathway.

New perspectives for prostate cancer treatment: in vitro inhibition of LNCaP and PC3 cell proliferation by amnion-derived mesenchymal stromal cells conditioned media

AIM

To determine whether normal human amnion-derived mesenchymal stromal cells (hAMSCs) secrete trophic mediators able to inhibit human prostate cancer cell lines growth.

METHODS

Human prostate cancer and normal cell lines were used. Mesenchymal stromal cells (MSC) were isolated through mechanical and enzymatic digestion from amniotic membranes and were evaluated for specific mesenchymal stromal cells antigens. Cell proliferation was examined by MTT assay. Staining with propidium iodide (PI) followed by flow cytometry was used to detect cell cycle phase.

RESULTS

hAMSC showed proper mesenchymal stem cells phenotype. We found that hAMSC conditioned media (CM) inhibited prostate cancer cells proliferation. Indeed, we demonstrated that hAMSC CM treatment increased percentage of G1 cancer cells and decreased percentage of cancer cells in S and G2M phases, suggesting that the hAMSC factors slow progression of prostate cancer cells through cell cycle inhibition.

CONCLUSIONS

Our study provide evidences that hAMSC microenvironment secretes soluble factors able to inhibit prostate cancer cells growth. This may represent a novel strategy to control proliferation of prostate cancer through modulation of the host microenvironment.

Low-oxygen tension and IGF-I promote proliferation and multipotency of placental mesenchymal stem cells (PMSCs) from different gestations via distinct signaling pathways

The microenvironment of placental mesenchymal stem cells (PMSCs) is dynamic throughout gestation and determines changes in cell fate. In vivo, PMSCs initially develop in low-oxygen tension and low IGF-I concentrations, and both increase gradually with gestation. The impact of varying concentrations of IGF-I and changing oxygen tension on PMSC signaling and multipotency was investigated in PMSCs from early (preterm) and late (term) gestation human placentae. Preterm PMSCs had greater proliferative response to IGF-I, which was further enhanced by low-oxygen tension. Low-oxygen tension alone was sufficient to induce ERK1/2 phosphorylation, whereas IGF-I was required for AKT (protein kinase B) phosphorylation. Low-oxygen tension prolonged ERK1/2 and AKT phosphorylation with a slowed phosphorylation decay even in presence of IGF-I. Low-oxygen tension maintained higher levels of IGF-I receptor and insulin receptor substrate 1 that were otherwise decreased by exposure to IGF-I and induced a differential phosphorylation pattern on IGF-I receptorβ and insulin receptor substrate 1. Phosphorylation of ERK1/2 and AKT was different between the preterm and term PMSCs, and phospho-AKT, and not phospho-ERK1/2, was the major determinant of PMSC proliferation and octamer-4 levels. These studies demonstrate that low-oxygen tension regulates the fate of PMSCs from early and late gestations in response to IGF-I, both independently and dependently, via specific signal transduction mechanisms.

Proteomic profiling of human placenta-derived mesenchymal stem cells upon transforming LIM mineralization protein-1 stimulation

Human placenta-derived mesenchymal stem cells (hPDMSCs) can differentiate into different types of cells and thus have tremendous potential for cell therapy and tissue engineering. LIM mineralization protein-1 (LMP-1) plays an important role in osteoblast differentiation, maturation and bone formation. To determine a global effect of LMP-1 on hPDMSCs, we designed a study using a proteomic approach combined with adenovirus-mediated gene transfer of LMP-1 to identify LMP-1-induced changes in hPDMSCs on proteome level. We have generated proteome maps of undifferentiated hPDMSCs and LMP-1 induced hPDMSCs. Two dimensional gel electrophoresis revealed 22 spots with at least 2.0-fold changes in expression and 15 differently expressed proteins were successfully identified by MALDI-TOF-MS. The proteins regulated by LMP-1 included cytoskeletal proteins, cadmium-binding proteins, and metabolic proteins, etc. The expression of some identified proteins was confirmed by further Western blot analyses. Our results will play an important role in better elucidating the underlying molecular mechanism in LMP-1 included hPDMSCs differentiation into osteoblasts.

Hypoxia enhances protective effect of placental-derived mesenchymal stem cells on damaged intestinal epithelial cells by promoting secretion of insulin-like growth factor-1

Apoptosis and necrosis of intestinal epithelial cells (IECs), induced by ischemia-reperfusion (I/R) injury, can lead to dysfunction of the intestinal barrier, which could cause multiple organ dysfunction syndromes. Mesenchymal stem cells (MSCs) have the potential of providing protective effects on damaged IECs via paracrine action. This study investigated whether hypoxia can enhance the protective effect of placental-derived MSCs (pMSCs) on H2O2-treated-caco2 cells, and explored the possible mechanism. The pMSCs isolated by tissue culture were fibroblast-like, positive for CD73, CD90 and CD105 and can differentiate into chondrocytes and endothelial cells. Five days after treatment with H2O2, the numbers of living caco2 cells significantly decreased. More live H2O2-treated-caco2 cells were observed in pMSCs hypoxia culture medium (pMSCs-HCM) than pMSCs normoxia culture medium (pMSCs-NCM), and the application of a specific antibody that blocked insulin-like growth factor-1 (IGF-1) leads to a significant decrease of the protective effect of pMSCs-HCM. Hypoxia can promote IGF-1 expression of pMSCs at mRNA and protein levels, and caco2 stably expressed IGF-1 receptor. Knocking down IGF-1 expression in pMSCs by siRNA resulted in a significant attenuation of the increase in apoptosis of H2O2-treated-caco2 cultured in pMSCs-HCM. In conclusion, hypoxia can increase the protective effect of pMSCs on H2O2-treated-caco2 cells via a promotion of their paracrine actions, and the key cytokine involved is IGF-1.

Neocartilage formation from mesenchymal stem cells grown in type II collagen-hyaluronan composite scaffolds

Three-dimensional (3D) collagen type II-hyaluronan (HA) composite scaffolds (CII-HA) which mimics the extracellular environment of natural cartilage were fabricated in this study. Rheological measurements demonstrated that the incorporation of HA increased the compression modulus of the scaffolds. An initial in vitro evaluation showed that scaffolds seeded with porcine chondrocytes formed cartilaginous-like tissue after 8 weeks, and HA functioned to promote the growth of chondrocytes into scaffolds. Placenta-derived multipotent cells (PDMC) and gingival fibroblasts (GF) were seeded on tissue culture polystyrene (TCPS), CII-HA films, and small intestinal submucosa (SIS) sheets for comparing their chondrogenesis differentiation potentials with those of adipose-derived adult stem cells (ADAS) and bone marrow-derived mesenchymal stem cells (BMSC). Among different cells, PDMC showed the greatest chondrogenic differentiation potential on both CII-HA films and SIS sheets upon TGF-β3 induction, followed by GF. This was evidenced by the up-regulation of chondrogenic genes (Sox9, aggrecan, and collagen type II), which was not observed for cells grown on TCPS. This finding suggested the essential role of substrate materials in the chondrogenic differentiation of PDMC and GF. Neocartilage formation was more obvious in both PDMC and GF cells plated on CII-HA composite scaffolds vs. 8-layer SIS at 28 days in vitro. Finally, implantation of PDMC/CII-HA constructs into NOD-SCID mice confirmed the formation of tissue-engineered cartilage in vivo.

Effects of ECM protein mimetics on adhesion and proliferation of chorion derived mesenchymal stem cells

BACKGROUND

We evaluated the effects of fibronectin, collagen, cadherin, and laminin based extracellular matrix (ECM) protein mimetics coated with mussel derived adhesive protein (MAP) on adhesion and proliferation of chorionic mesenchymal stem cells (cMSCs).

METHODS

Human placental chorionic tissues from term third-trimester pregnancies (n=3) were used. The cMSCs were cultured on rationally designed ECM protein mimetics coated with MAP on plastic surfaces with the addition of reduced fetal bovine serum (0.5%, 1% FBS). Adhesion capabilities were monitored by a real time cell analysis system (RTCA) utilizing an impedance method. Proliferation capabilities were monitored by RTCA and MTS assay.

RESULTS

Of the ECM protein mimetics tested, GRGDSP(FN) coated surfaces exhibited the highest adhesion and proliferation capabilities on RTCA at FBS concentration of 0.5% and 1%. When 0.5% FBS was added to ECM protein mimetics during the MTS assay, GRGDSP(FN), REDV(FN), and collagen mimetics, GPKGAAGEPGKP(ColI) showed higher cMSCs proliferation compared with the control. When 1% FBS was added, GRGDSP(FN) and TAIPSCPEGTVPLYS(ColIV) showed significant cMSCs proliferation capacity.

CONCLUSIONS

Fibronectin mimetics, GRGDSP(FN) amino acid sequence showed the highest adhesion and proliferation capabilities. In addition, results from RTCA assessment of cell viability correlated well with the tetrazolium-based MTS assay.

RECENT DEVELOPMENTS IN THERAPIES WITH STEM CELLS FROM AMNIOTIC FLUID AND PLACENTA

Significant advances in the field of regenerative medicine have intensified the search for novel sources of stem cells with potential for therapy. Although embryonic and adult tissues can be used for the isolation of pluripotent stem cells, significant limitations including ethical concerns, complexity of isolation/culture and tumorigenicity have hindered translation of laboratory findings to clinical practice.

Phenotypic and functional characterization of mesenchymal stem cells from chorionic villi of human term placenta

BACKGROUND

Bone marrow derived mesenchymal stem cells (BM-MSCs) are used extensively in transplantation but their use is associated with many problems including low abundance in BM, low overall number, decreased differentiation potential with age and the invasive isolation procedures needed to obtain BM. We report a novel method of isolating placental MSCs (pMSCs) from chorionic villi, which exhibit the phenotypic and functional characteristics that will make them an attractive source of MSCs for cell-based therapy.

METHODS

A novel explant approach was used to isolate pMSCs from chorionic villi of human placentae. These pMSCs were characterized by flow cytometry and were differentiated into adipocytes, osteocytes and chondrocytes using differentiation medium as demonstrated by cytochemical staining. The gene and protein expression profiles of pMSCs were also characterized using real time polymerase chain reaction (PCR) and flow cytometry, respectively. In addition, cytokine secretion by pMSCs was also analysed using sandwich enzyme-linked immunosorbent assay (ELISA) technique. Moreover, the migration and proliferation potentials of pMSCs were also determined.

RESULTS

pMSCs were isolated from fetal part of the chorionic villi and these pMSCs expressed CD44, CD90, CD105, CD146, CD166 and HLA-ABC but not CD14, CD19, CD40, CD45, CD80, CD83, CD86 and HLA-DR. In addition, these pMSCs differentiated into osteocytes, chondrocytes and adipocytes and they also expressed several adhesion molecules, chemokines/receptors, growth factor receptors and cytokines/receptors. Moreover, they secreted many cytokines (IL-1Ra, IL6, IL8, IL10, IL11 and IL15) and they were able to proliferate. Furthermore, they migrated in response to chemotactic factors including stromal cell-derived factor-1 (SDF-1), platelet derived growth factor (PDGF), hepatocyte growth factor (HGF), and monocyte chemotactic protein-1 (MCP-1).

CONCLUSIONS

We devised a novel explant method of isolating pMSCs that expressed many biological factors responsible for mediating cellular processes such as migration/homing, immune modulation and angiogenesis. Therefore, we suggest that pMSCs prepared from human term placental chorionic villous explants are an attractive source of MSCs for cell therapy.

Human mesenchymal stem cells: a bank perspective on the isolation, characterization and potential of alternative sources for the regeneration of musculoskeletal tissues

The continuous discovery of human mesenchymal stem cells (hMSCs) in different tissues is stirring up a tremendous interest as a cell source for regenerative medicine therapies. Historically, hMSCs have been always considered a sub-population of mononuclear cells present in the bone marrow (BM). Although BM-hMSCs are still nowadays considered as the most promising mesenchymal stem cell population to reach the clinics due to their capacity to differentiate into multiple tissues, hMSCs derived from other adult and fetal tissues have also demonstrated to possess similar differentiation capacities. Furthermore, different reports have highlighted a higher recurrence of hMSCs in some of these tissues as compared to BM. This offer a fascinating panorama for cell banking, since the creation of a stem cell factory could be envisioned where hMSCs are stocked and used for ad hoc clinical applications. In this review, we summarize the main findings and state of the art in hMSCs isolation, characterization, and differentiation from alternative tissue sources and we attempt to compare their potency for musculoskeletal regeneration.

Isolation and characterization of human amniotic mesenchymal stem cells and their chondrogenic differentiation

BACKGROUND

Freshly isolated human amniotic mesenchymal (fHAM) cells contain somatic stem cells possessing proliferative ability and pluripotency, including a chondrogenic lineage. However, little is known about the biology of amnion-derived mesenchymal stem cells (MSCs) because fHAM cells can barely survive to expand under culture conditions in vitro for a long time.

METHODS

In this study, we separated fHAM cells and seeded them to isolate MSCs and analyze its character. In addition, suitable chondrogenic growth factor was determined by pellet culture, and their viability under xenogenic environment was examined by transplantation into rabbit knee joints.

RESULTS

We succeeded in purifying proliferative subpopulations of fHAM cells, which could continue to proliferate more than 50 cumulative population doubling levels, and designated them as HAMα cells. Flow cytometry analysis revealed that they were positive for MSC markers (CD44, CD73, CD90, and CD105) and negative for hematopoietic cell markers (CD34, CD14, and CD45) and major histocompatibility complex class II antigen (human leukocyte antigen-DR). The expression of various stem-cell markers such as OCT3/4, C-MYC, SOX2, NANOG, CD44, SSEA-3, and SSEA-4 was also proved by immunocytochemical staining. Pellet culture using chondrogenic medium supplemented with transforming growth factor β3, transforming growth factor β3 plus bone morphogenetic protein (BMP)-2, or BMP-2 implied that supplementation of BMP-2 alone most effectively induced chondrogenesis in vitro. Xenotransplantation of HAMα cells achieved 8-week survival in vivo.

CONCLUSIONS

These results suggest that HAMα cells correspond to MSCs that are highly proliferative and multipotent. Their chondrogenic potential and low immunogenicity indicate that HAMα cells could be an allotransplantable cell resource for cartilage repair.

Therapeutic superiority for cartilage repair by CD271-positive marrow stromal cell transplantation

Recent reports indicated that human isolated CD271+ bone marrow mesenchymal stromal cells (BM-MSCs) have a greater expansion and potential for multipotent differentiation including chondrogenesis than classical plastic adherent (PA) BM-MSCs in vitro. Therefore, we set up a hypothesis that CD271+ MSCs may have a greater chondrogenic potential than PA-MSCs in vitro and in vivo. We investigated the superiority of CD271+ MSCs on chondrogenesis using in vitro expansion and pellet culture system and in vivo rat model of cartilage defect when compared to PA-MSCs. In the in vitro study, CD271+ MSCs showed higher expansion potential and produced larger pellets with higher expressions of chondrogenic genes when compared to the control groups. During the culture, CD271 expression decreased, which resulted in decreased chondrogenesis. In the in vivo study, immunohistochemical staining demonstrated differentiated human chondrocytes identified as double-stained cells with human-specific collagen type 2 and human leukocyte antigen-ABC in CD271+ and PA groups. The number of double-stained cells was significantly higher in the CD271+ group than PA group. Real-time RT-PCR analysis of tissue RNA isolated from the chondral defect site for human-specific chondrogenic markers demonstrated a significantly higher expression in CD271+ group than PA group. Macroscopic examination of chondral defect sites at week 8 revealed glossy white and well-integrated repaired tissues in the CD271+ and PA groups, but not in the PBS group. The average histological score in the CD271+ group was significantly greater than in the other groups. Apoptosis analysis at the cell transplanted site with TUNEL staining showed that the CD271+ group had significantly fewer apoptotic chondrocytes compared with the PA group. These results indicate that CD271+ MSCs have a greater chondrogenic potential than PA-MSCs in both in vitro and in vivo conditions.

Clinical grade adult stem cell banking

There has been a great deal of scientific interest recently generated by the potential therapeutic applications of adult stem cells in human care but there are several challenges regarding quality and safety in clinical applications and a number of these challenges relate to the processing and banking of these cells ex-vivo. As the number of clinical trials and the variety of adult cells used in regenerative therapy increases, safety remains a primary concern. This has inspired many nations to formulate guidelines and standards for the quality of stem cell collection, processing, testing, banking, packaging and distribution. Clinically applicable cryopreservation and banking of adult stem cells offers unique opportunities to advance the potential uses and widespread implementation of these cells in clinical applications. Most current cryopreservation protocols include animal serum proteins and potentially toxic cryoprotectant additives (CPAs) that prevent direct use of these cells in human therapeutic applications. Long term cryopreservation of adult stem cells under good manufacturing conditions using animal product free solutions is critical to the widespread clinical implementation of ex-vivo adult stem cell therapies. Furthermore, to avoid any potential cryoprotectant related complications, reduced CPA concentrations and efficient post-thaw washing to remove CPA are also desirable. The present review focuses on the current strategies and important aspects of adult stem cell banking for clinical applications. These include current good manufacturing practices (cGMPs), animal protein free freezing solutions, cryoprotectants, freezing & thawing protocols, viability assays, packaging and distribution. The importance and benefits of banking clinical grade adult stem cells are also discussed.

Immunosuppressive properties of mesenchymal stem cells

Mesenchymal stem cells (MSC) can be isolated from different adult tissues including bone marrow, adipose tissue, cord blood and placenta. MSCs modulate the immune function of the major immune cell populations involved in alloantigen recognition and elimination, including antigen presenting cells, T cells, B cells and natural killer cells. Many clinical trials are currently underway that employ MSCs to treat human immunological diseases. However, the molecular mechanism that mediates the immunosuppressive effect of MSCs is still unclear and the safety of using MSC in patient needs further confirmation. Here, we review the cytokines that activate MSCs and the soluble factors produced by MSCs, which allow them to exert their immunosuppressive effects. We review the mechanism responsible, at least in part, for the immune suppressive effects of MSCs and highlight areas of research required for a better understanding of MSC immune modulation.

The immunomodulatory and neuroprotective effects of mesenchymal stem cells (MSCs) in experimental autoimmune encephalomyelitis (EAE): a model of multiple sclerosis (MS)

Mesenchymal stem cells (MSCs) are multipotent cells that differentiate into the mesenchymal lineages of adipocytes, osteocytes and chondrocytes. MSCs can also transdifferentiate and thereby cross lineage barriers, differentiating for example into neurons under certain experimental conditions. MSCs have anti-proliferative, anti-inflammatory and anti-apoptotic effects on neurons. Therefore, MSCs were tested in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), for their effectiveness in modulating the pathogenic process in EAE to develop effective therapies for MS. The data in the literature have shown that MSCs can inhibit the functions of autoreactive T cells in EAE and that this immunomodulation can be neuroprotective. In addition, MSCs can rescue neural cells via a mechanism that is mediated by soluble factors, which provide a suitable environment for neuron regeneration, remyelination and cerebral blood flow improvement. In this review, we discuss the effectiveness of MSCs in modulating the immunopathogenic process and in providing neuroprotection in EAE.

Multipotent stromal stem cells from human placenta demonstrate high therapeutic potential

We describe human chorionic mesenchymal stem cell (hCMSC) lines obtained from the chorion of human term placenta with high therapeutic potential in human organ pathology. hCMSCs propagated for more than 100 doublings without a decrease in telomere length and with no telomerase activity. Cells were highly positive for the embryonic stem cell markers OCT-4, NANOG, SSEA-3, and TRA-1-60. In vitro, cells could be differentiated into neuron-like cells (ectoderm), adipocytes, osteoblasts, endothelial-like cells (mesoderm), and hepatocytes (endoderm)-derivatives of all three germ layers. hCMSCs effectively facilitated repair of injured epithelium as demonstrated in an ex vivo-perfused human lung preparation injured by Escherichia coli endotoxin and in in vitro human lung epithelial cultures. We conclude that the chorion of human term placenta is an abundant source of multipotent stem cells that are promising candidates for cell-based therapies.

In vivo tracking of mesechymal stem cells using fluorescent nanoparticles in an osteochondral repair model

We devised and tested an in vivo system to monitor the migration of mesenchymal stem cells (MSCs) within the marrow cavity. In vitro studies confirmed that platelet-derived growth factor (PDGF)-AA had the most potent chemotactic effect of the tested factors, and possessed the greatest number of receptors in MSCs. MSCs were labeled with fluorescent nanoparticles and injected into the marrow cavity of nude rats through osteochondral defects created in the distal femur. The defects were sealed with HCF (heparin-conjugated fibrin) or PDGF-AA-loaded HCF. In the HCF-only group, the nanoparticle-labeled MSCs dispersed outside the marrow cavity within 3 days after injection. In the PDGF-AA-loaded HCF group, the labeled cells moved time-dependently for 14 days toward the osteochondral defect. HCF-PDGF in low dose (LD; 8.5 ng/µl) was more effective than HCF-PDGF in high dose (HD; 17 ng/µl) in recruiting the MSCs to the osteochondral defect. After 21 days, the defects treated with PDGF and transforming growth factor (TGF)-β1-loaded HCF showed excellent cartilage repair compared with other groups. Further studies confirmed that this in vivo osteochondral MSCs tracking system (IOMTS) worked for other chemoattractants (chemokine (C-C motif) ligand 2 (CCL2) and PDGF-BB). IOMTS can provide a useful tool to examine the effect of growth factors or chemokines on endogenous cartilage repair.

Long-term cultured human term placenta-derived mesenchymal stem cells of maternal origin displays plasticity

Mesenchymal stem cells (MSCs) are an alluring therapeutic resource because of their plasticity, immunoregulatory capacity and ease of availability. Human BM-derived MSCs have limited proliferative capability, consequently, it is challenging to use in tissue engineering and regenerative medicine applications. Hence, placental MSCs of maternal origin, which is one of richest sources of MSCs were chosen to establish long-term culture from the cotyledons of full-term human placenta. Flow analysis established bonafied MSCs phenotypic characteristics, staining positively for CD29, CD73, CD90, CD105 and negatively for CD14, CD34, CD45 markers. Pluripotency of the cultured MSCs was assessed by in vitro differentiation towards not only intralineage cells like adipocytes, osteocytes, chondrocytes, and myotubules cells but also translineage differentiated towards pancreatic progenitor cells, neural cells, and retinal cells displaying plasticity. These cells did not significantly alter cell cycle or apoptosis pattern while maintaining the normal karyotype; they also have limited expression of MHC-II antigens and are Naive for stimulatory factors CD80 and CD 86. Further soft agar assays revealed that placental MSCs do not have the ability to form invasive colonies. Taking together all these characteristics into consideration, it indicates that placental MSCs could serve as good candidates for development and progress of stem-cell based therapeutics.

Isolation and cellular properties of mesenchymal cells derived from the decidua of human term placenta

The clinical promise of cell-based therapies is generally recognized, and has driven an intense search for good cell sources. In this study, we isolated plastic-adherent cells from human term decidua vera, called decidua-derived-mesenchymal cells (DMCs), and compared their properties with those of bone marrow-derived-mesenchymal stem cells (BM-MSCs). The DMCs strongly expressed the mesenchymal cell marker vimentin, but not cytokeratin 19 or HLA-G, and had a high proliferative potential. That is, they exhibited a typical fibroblast-like morphology for over 30 population doublings. Cells phenotypically identical to the DMCs were identified in the decidua vera, and genotyping confirmed that the DMCs were derived from the maternal components of the fetal adnexa. Flow cytometry analysis showed that the expression pattern of CD antigens on the DMCs was almost identical to that on BM-MSCs, but some DMCs expressed the CD45 antigen, and over 50% of them also expressed anti-fibroblast antigen. In vitro, the DMCs showed good differentiation into chondrocytes and moderate differentiation into adipocytes, but scant evidence of osteogenesis, compared with the BM-MSCs. Gene expression analysis showed that, compared with BM-MSCs, the DMCs expressed higher levels of TWIST2 and RUNX2 (which are associated with early mesenchymal development and/or proliferative capacity), several matrix metalloproteinases (MMP1, 3, 10, and 12), and cytokines (BMP2 and TGFB2), and lower levels of MSX2, interleukin 26, and HGF. Although DMCs did not show the full multipotency of BM-MSCs, their higher proliferative ability indicates that their cultivation would require less maintenance. Furthermore, the use of DMCs avoids the ethical concerns associated with the use of embryonic tissues, because they are derived from the maternal portion of the placenta, which is otherwise discarded. Thus, the unique properties of DMCs give them several advantages for clinical use, making them an interesting and attractive alternative to MSCs for regenerative medicine.

Isolation and characterization of mesenchymal stem cells from human umbilical cord blood: reevaluation of critical factors for successful isolation and high ability to proliferate and differentiate to chondrocytes as compared to mesenchymal stem cells from bone marrow and adipose tissue

Human umbilical cord blood (CB) is a potential source for mesenchymal stem cells (MSC) capable of forming specific tissues, for example, bone, cartilage, or muscle. However, difficulty isolating MSC from CB (CB-MSC) has impeded their clinical application. Using more than 450 CB units donated to two public CB banks, we found that successful cell recovery fits a hyper-exponential function of time since birth with very high fidelity. Additionally, significant improvement in the isolation of CB-MSC was achieved by selecting cord blood units having a volume ≥90  ml and time ≤2  h after donor's birth. This resulted in 90% success in isolation of CB-MSC by density gradient purification and without a requirement for immunoaffinity methods as previously reported. Using MSC isolated from bone marrow (BM-MSC) and adipose tissue (AT-MSC) as reference controls, we observed that CB-MSC exhibited a higher proliferation rate and expanded to the order of the 1 × 10(9)  cells required for cell therapies. CB-MSC showed karyotype stability after prolonged expansion. Functionally, CB-MSC could be more readily induced to differentiate into chondrocytes than could BM-MSC and AT-MSC. CB-MSC showed immunosuppressive activity equal to that of BM-MSC and AT-MSC. Collectively, our data indicate that viable CB-MSC could be obtained consistently and that CB should be reconsidered as a practical source of MSC for cell therapy and regenerative medicine using the well established CB banking system.

Perinatal sources of mesenchymal stem cells: Wharton's jelly, amnion and chorion

Recently, stem cell biology has become an interesting topic, especially in the context of treating diseases and injuries using transplantation therapy. Several varieties of human stem cells have been isolated and identified in vivo and in vitro. Ideally, stem cells for regenerative medical application should be found in abundant quantities, harvestable in a minimally invasive procedure, then safely and effectively transplanted to either an autologous or allogenic host. The two main groups of stem cells, embryonic stem cells and adult stem cells, have been expanded to include perinatal stem cells. Mesenchymal stem cells from perinatal tissue may be particularly useful in the clinic for autologous transplantation for fetuses and newborns, and after banking in later stages of life, as well as for in utero transplantation in case of genetic disorders.This review highlights the characteristics and therapeutic potential of three human mesenchymal stem cell types obtained from perinatal sources: Wharton's jelly, the amnion, and the chorion.

Spheroid formation of mesenchymal stem cells on chitosan and chitosan-hyaluronan membranes

Stem cells can lose their primitive properties during in vitro culture. The culture substrate may affect the behavior of stem cells as a result of cell-substrate interaction. The maintenance of self-renewal for adult human mesenchymal stem cells (MSCs) by a biomaterial substrate, however, has not been reported in literature. In this study, MSCs isolated from human adipose (hADAS) and placenta (hPDMC) were cultured on chitosan membranes and those further modified by hyaluronan (chitosan-HA). It was observed that the MSCs of either origin formed three-dimensional spheroids that kept attached on the membranes. Spheroid formation was associated with the increased MMP-2 expression. Cells on chitosan-HA formed spheroids more quickly and the size of spheroids were larger than on chitosan alone. The expression of stemness marker genes (Oct4, Sox2, and Nanog) for MSCs on the materials was analyzed by the real-time RT-PCR. It was found that formation of spheroids on chitosan and chitosan-HA membranes helped to maintain the expression of stemness marker genes of MSCs compared to culturing cells on polystyrene dish. The maintenance of stemness marker gene expression was especially remarkable in hPDMC spheroids (vs. hADAS spheroids). Blocking CD44 by antibodies prevented the spheroid formation and decreased the stemness gene expression moderately; while treatment by Y-27632 compound inhibited the spheroid formation and significantly decreased the stemness gene expression. Upon chondrogenic induction, the MSC spheroids showed higher levels of Sox9, aggrecan, and collagen type II gene expression and were stained positive for glycosaminoglycan and collagen type II. hPDMC had better chondrogenic differentiation potential than hADAS upon induction. Our study suggested that the formation of adhered spheroids on chitosan and chitosan-HA membranes may sustain the expression of stemness marker genes of MSCs and increase their chondrogenic differentiation capacity. The Rho/Rho-associated kinase (ROCK) signaling pathway may be involved in spheroid formation.

Prenatally harvested cells for cardiovascular tissue engineering: fabrication of autologous implants prior to birth

Using the principal of tissue engineering, several groups have demonstrated the feasibility of creating heart valves, blood vessels, and myocardial structures using autologous cells and biodegradable scaffold materials. In the current cardiovascular clinical scenario, the main medical need for a tissue engineering solution is in the field of pediatric applications treating congenital heart disease. In these young patients, the introduction of autologous viable and growing replacement structures, such as tissue engineered heart valves and vessels, would substantially reduce today's severe therapeutic limitations, which are mainly due to the need for repeat reoperations to adapt the current artificial prostheses to somatic growth. Based on high resolution imaging techniques, an increasing number of defects are diagnosed already prior to birth around week 20. For interventions, cells should be obtained already during pregnancy to provide tissue engineered implants either at birth or even prenatally. In our recent studies human fetal mesenchymal stem cells were isolated from routinely sampled prenatal amniotic fluid or chorionic villus specimens and expanded in vitro. Fresh and cryopreserved samples were used. After phenotyping and genotyping, cells were seeded onto synthetic biodegradable scaffolds and conditioned in a bioreactor. Leaflets were endothelialized with either amniotic fluid- or umbilical cord blood-derived endothelial progenitor cells and conditioned. Resulting tissues were analyzed by histology, immunohistochemistry, biochemistry (amounts of extracellular matrix, DNA), mechanical testing, and scanning electron microscopy (SEM) and were compared with native neonatal heart valve leaflets. Genotyping confirmed their fetal origin, and fresh versus cryopreserved cells showed comparable myofibroblast-like phenotypes. Neo-tissues exhibited organization, cell phenotypes, extracellular matrix production, and DNA content comparable to their native counterparts. Leaflet surfaces were covered with functional endothelia. SEM showed morphologically cellular distribution throughout the polymer and smooth surfaces. Mechanical profiles approximated those of native heart valves. These in vitro studies demonstrated the principal feasibility of using various human cell types isolated from fetal sources for cardiovascular tissue engineering. Umbilical cord blood-, amniotic fluid- and chorionic villi-derived cells have shown promising potential for the clinical realization of this congenital tissue engineering approach. Based on these results, future research must aim at further investigation as well as preclinical evaluation of prenatally harvested stem- or progenitor cells with regard to their potential for clinical use.

Synergistic effect of adipose-derived stem cell therapy and bone marrow progenitor recruitment in ischemic heart

Human multipotent adipose-derived stem cells (hMADSCs) have recently been isolated featuring extensive expansion capacity ex vivo. We tested the hypothesis that hMADSC transplantation might contribute to cardiac functional recovery by its direct or indirect effect on myocardial infarction (MI). Nude rats were either transplanted with hMADSCs or PBS (control) in ischemic myocardium immediately following MI. Echocardiographical assessment of cardiac function after MI with hMADSCs showed significant improvement of each parameter compared to that with PBS. Histological analysis also showed significantly reduced infarct size and increased capillary density in peri-infarct myocardium by hMADSC treatment. However, remarkable transdifferentiation of hMADSCs into cardiac or vascular lineage cells was not observed. Despite the less transdifferentiation capacity, hMADSCs produced robust multiple pro-angiogenic growth factors and chemokines, such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and stromal cell-derived factor-1α (SDF-1α). Specifically, hMADSC-derived SDF-1α had a crucial role for cooperative angiogenesis, with the paracrine effect of hMADSCs and Tie2-positive bone marrow (BM) progenitor recruitment in ischemic myocardium. hMADSCs exhibit a therapeutic effect on cardiac preservation following MI, with the production of VEGF, bFGF, and SDF-1α showing paracrine effects and endogenous BM stem/progenitor recruitment to ischemic myocardium rather than its direct contribution to tissue regeneration.