Human amniotic fluid-derived stem cells have characteristics of multipotent stem cells

Equine Musculoskeletal Pathologies: Clinical Approaches and Therapeutical Perspectives-A Review

Musculoskeletal injuries such as equine osteoarthritis, osteoarticular defects, tendonitis/desmitis, and muscular disorders are prevalent among sport horses, with a fair prognosis for returning to exercise or previous performance levels. The field of equine medicine has witnessed rapid and fruitful development, resulting in a diverse range of therapeutic options for musculoskeletal problems. Staying abreast of these advancements can be challenging, prompting the need for a comprehensive review of commonly used and recent treatments. The aim is to compile current therapeutic options for managing these injuries, spanning from simple to complex physiotherapy techniques, conservative treatments including steroidal and non-steroidal anti-inflammatory drugs, hyaluronic acid, polysulfated glycosaminoglycans, pentosan polysulfate, and polyacrylamides, to promising regenerative therapies such as hemoderivatives and stem cell-based therapies. Each therapeutic modality is scrutinized for its benefits, limitations, and potential synergistic actions to facilitate their most effective application for the intended healing/regeneration of the injured tissue/organ and subsequent patient recovery. While stem cell-based therapies have emerged as particularly promising for equine musculoskeletal injuries, a multidisciplinary approach is underscored throughout the discussion, emphasizing the importance of considering various therapeutic modalities in tandem.

Polycaprolactone/poly L-lactic acid nanofibrous scaffold improves osteogenic differentiation of the amniotic fluid-derived stem cells

Using stem cells is one of the most important determining factors in repairing lesions using regenerative medicine. Obtaining adult stem cells from patients is a perfect choice, but it is worth noting that their differentiation and proliferation potential decreases as the patient ages. For this reason, the use of amniotic fluid stem cells can be one of the excellent alternatives. This research aimed to investigate the osteogenic differentiation potential of the amniotic fluid stem cells while cultured on the polycaprolactone/poly L-lactic acid nanofibrous scaffold. Scaffolds were qualitatively evaluated by a scanning electron microscope, and their hydrophilicity and mechanical properties were studied using contact angle and tensile test, respectively. The biocompatibility and non-toxicity of the nanofibers were also evaluated using viability assay. The osteo-supportive capacity of the nanofibers was examined using alizarin red staining, alkaline phosphatase activity, and calcium release measurement. Finally, the expression level of four important bone-related genes was determined quantitatively. The results demonstrated that the mineralization rate, alkaline phosphatase activity, intracellular calcium, and bone-related genes increased significantly in the cells cultured on the polycaprolactone/poly L-lactic acid scaffold compared to the cells cultured on the tissue culture plate as a control. According to the results, it can be concluded that the polycaprolactone/poly L-lactic acid nanofibrous scaffold surprisingly improved the osteogenic differentiation potential of the amniotic fluid stem cells and, in combination with polycaprolactone/poly L-lactic acid nanofibers could be a promising candidate as bone implants.

Combination of human platelet lysate and 3D gelatin scaffolds to enhance osteogenic differentiation of human amniotic fluid derived mesenchymal stem cells

Bone disorders are major health issues requiring specialized care; however, the traditional bone grafting method had several limitations. Thus, bone tissue engineering has become a potential alternative. In therapeutic treatments, using fetal bovine serum (FBS) as a culture supplement may result in the risk of contamination and host immunological response; therefore, human platelet lysate (hPL) has been considered a viable alternative source. This study attempted to compare the effectiveness and safety of different culture supplements, either FBS or hPL, on the osteoblastic differentiation potential of mesenchymal stem cells derived from human amniotic fluid (hAF-MSCs) under a three-dimensional gelatin scaffold. The results indicate that hAF-MSCs have the potential to be used in clinical applications as they meet the criteria for mesenchymal stem cells based on their morphology, the expression of a particular surface antigen, their proliferation ability, and their capacity for multipotent differentiation. After evaluation by MTT and Alamar blue proliferation assay, 10% of hPL was selected. The osteogenic differentiation of hAF-MSCs under three-dimensional gelatin scaffold using osteogenic-induced media supplemented with hPL was achievable and markedly stimulated osteoblast differentiation. Moreover, the expressions of osteoblastogenic related genes, including OCN, ALP, and COL1A1, exhibited the highest degree of expression under hPL-supplemented circumstances when compared with the control and the FBS-supplemented group. The induced cells under hPL-supplemented conditions also presented the highest ALP activity level and the greatest degree of calcium accumulation. These outcomes would indicate that hPL is a suitable substitute for animal derived serum. Importantly, osteogenic differentiation of human amniotic fluid derived mesenchymal stem cells using hPL-supplemented media and three-dimensional scaffolds may open the door to developing an alternative construct for repairing bone defects.

Amniotic Fluid Stem Cells: What They Are and What They Can Become

In the last two decades, fetal amniotic fluid stem cells progressively attracted attention in the context of both basic research and the development of innovative therapeutic concepts. They exhibit broadly multipotent plasticity with the ability to differentiate into cells of all three embryonic germ layers and low immunogenicity. They are convenient to maintain, highly proliferative, genomically stable, non-tumorigenic, perfectly amenable to genetic modifications, and do not raise ethical concerns. However, it is important to note that among the various fetal amniotic fluid cells, only c-Kit+ amniotic fluid stem cells represent a distinct entity showing the full spectrum of these features. Since amniotic fluid additionally contains numerous terminally differentiated cells and progenitor cells with more limited differentiation potentials, it is of highest relevance to always precisely describe the isolation procedure and characteristics of the used amniotic fluid-derived cell type. It is of obvious interest for scientists, clinicians, and patients alike to be able to rely on up-todate and concisely separated pictures of the utilities as well as the limitations of terminally differentiated amniotic fluid cells, amniotic fluid-derived progenitor cells, and c-Kit+ amniotic fluid stem cells, to drive these distinct cellular models towards as many individual clinical applications as possible.

Chick Early Amniotic Fluid (ceAF) Deters Tumorigenesis via Cell Cycle Arrest and Apoptosis

In recent years, amniotic fluids have gained attention in cancer research. They have an influential role in protecting embryos against several anomalies. Chick early amniotic fluid (ceAF)-amniotic fluid isolated from growing chicken-has been used in many other studies, including myocardial infarctions and skin regeneration. In this study, we employed ceAF's promising therapeutic applications against tumorigenesis in both in vitro and in vivo studies. We selected three robust proliferating tumor cell lines: BCaP37, MCF7, and RKO. We found that selective dosage is required to obtain maximum impact to deter tumorigenesis. ceAF not only disrupted the uniform colonies of tumor cell lines via disturbing mitochondrial transmembrane potential, but also arrested many cells at growing G1 state via working agonistically with aphidicolin. The significant inhibition of tumor metastasis by ceAF was indicated by in vivo models. This leads to apoptosis analysis as verified by annexin-V staining stays and immunoblotting of critical proteins as cell cycle meditators and apoptosis regulators. Not only on the protein level, but we also tested ceAF's therapeutic potentials on mRNA levels as indicated by quantitative real-time PCR summarizing the promising role of ceAF in deterring tumor progression. In conclusion, our study reveals the potent role of ceAF against tumorigenesis in breast cancer and colon carcinoma. Further studies will be required to determine the critical components present in ceAF and its purification to narrow down this study.

Sex Differences in Protein Expression and Their Perturbations in Amniotic Fluid Cells of Down Syndrome Fetuses

Down syndrome (DS) is the most common chromosomal condition associated with intellectual disability and is characterized by a variety of additional clinical findings. The pathogenesis of DS and the differences between the sexes are not clear. In order to identify differentially expressed proteins that might be employed as potential biological markers and elucidate the difference in pathogenesis between different genders of T21 fetuses, providing clues for individualized detection and treatment is essential. Amniocyte samples of T21 males, T21 females, CN males, and CN females were collected by amniocentesis. The quantitative value of the peptide corresponding to each sample was determined through quantitative analysis by mass spectrometry. We identified many differentially expressed proteins between T21 fetuses and CN fetuses/T21 males and CN males/T21 females and CN females/and T21 males and T21 females. These differential proteins are associated with many important biological processes and affect the development of multiple systems, including the heart, hematopoietic, immune, reproductive, and nervous systems. Our results show sex-specific modulation of protein expression and biological processes and provide new insights into sex-specific differences in the pathogenesis of DS.

Store-Operated Ca2+ Entry Contributes to Piezo1-Induced Ca2+ Increase in Human Endometrial Stem Cells

Endometrial mesenchymal stem cells (eMSCs) are a specific class of stromal cells which have the capability to migrate, develop and differentiate into different types of cells such as adipocytes, osteocytes or chondrocytes. It is this unique plasticity that makes the eMSCs significant for cellular therapy and regenerative medicine. Stem cells choose their way of development by analyzing the extracellular and intracellular signals generated by a mechanical force from the microenvironment. Mechanosensitive channels are part of the cellular toolkit that feels the mechanical environment and can transduce mechanical stimuli to intracellular signaling pathways. Here, we identify previously recorded, mechanosensitive (MS), stretch-activated channels as Piezo1 proteins in the plasma membrane of eMSCs. Piezo1 activity triggered by the channel agonist Yoda1 elicits influx of Ca²⁺, a known modulator of cytoskeleton reorganization and cell motility. We found that store-operated Ca²⁺ entry (SOCE) formed by Ca²⁺-selective channel ORAI1 and Ca²⁺ sensors STIM1/STIM2 contributes to Piezo1-induced Ca²⁺ influx in eMSCs. Particularly, the Yoda1-induced increase in intracellular Ca²⁺ ([Ca²⁺]_i) is partially abolished by 2-APB, a well-known inhibitor of SOCE. Flow cytometry analysis and wound healing assay showed that long-term activation of Piezo1 or SOCE does not have a cytotoxic effect on eMSCs but suppresses their migratory capacity and the rate of cell proliferation. We propose that the Piezo1 and SOCE are both important determinants in [Ca²⁺]_i regulation, which critically affects the migratory activity of eMSCs and, therefore, could influence the regenerative potential of these cells.

Effects of single and multiple transplantations of human umbilical cord mesenchymal stem cells on the recovery of ovarian function in the treatment of premature ovarian failure in mice

BACKGROUND

Currently, there is no effective treatment for premature ovarian failure (POF), and stem cell therapy is considered the most promising treatment. Human umbilical cord blood mesenchymal stem cells (hUC-MSCs) have shown good regenerative ability in various diseases, including POF; however, their underlying mechanism and dosage for POF treatment remain unclear. This study aimed to compare the effect of single and multiple injections of hUC-MSCs on ovarian function repair in chemotherapy-induced POF.

METHODS

Female mice were intraperitoneally injected with 30 mg/kg busulfan and 120 mg/kg cyclophosphamide (CTX) to induce POF. In the single hUC-MSC injection group, hUC-MSCs were transplanted into mice D7 after CTX and busulfan administration, while in the multiple injection group, hUC-MSCs were transplanted on D7, D14, and D21 after CTX and busulfan administration. We evaluated the ovarian morphology, fertility, follicle-stimulating hormone and estradiol concentrations, follicle count, POF model, and cell transplantation results. In addition, real-time polymerase chain reaction, immunohistochemistry, and miRNA and mRNA chips were used to evaluate the effect of the cell therapy.

RESULTS

Ovary size, number of follicle at all developmental stages, and fertility were significantly reduced in the POF group compared with the control. Under hUC-MSC treatment, the ovarian morphology and follicle count were significantly restored, and fertility was significantly increased. By comparing the single and multiple hUC-MSC injection groups, we found that the anti-Müllerian hormone and Ki-67 levels were significantly increased in the multiple hUC-MSC group on D60 after chemotherapy. The expression of stimulating hormone receptors, inhibin α, and inhibin β was significantly restored, and the therapeutic effect was superior to that of the single hUC-MSC injection group.

CONCLUSION

These results indicate that hUC-MSCs can restore the structure of injured ovarian tissue and its function in chemotherapy-induced POF mice and ameliorate fertility. Multiple hUC-MSC transplantations have a better effect on the recovery of ovarian function than single hUC-MSC transplantation in POF.

Three-dimensional migration of human amniotic fluid stem cells involves mesenchymal and amoeboid modes and is regulated by mTORC1

Three‐dimensional (3D) cell migration is an integral part of many physiologic processes. Although being well studied in the context of adult tissue homeostasis and cancer development, remarkably little is known about the invasive behavior of human stem cells. Using two different kinds of invasion assays, this study aimed at investigating and characterizing the 3D migratory capacity of human amniotic fluid stem cells (hAFSCs), a well‐established fetal stem cell type. Eight hAFSC lines were found to harbor pronounced potential to penetrate basement membrane (BM)‐like matrices. Morphological examination and inhibitor approaches revealed that 3D migration of hAFSCs involves both the matrix metalloprotease‐dependent mesenchymal, elongated mode and the Rho‐associated protein kinase‐dependent amoeboid, round mode. Moreover, hAFSCs could be shown to harbor transendothelial migration capacity and to exhibit a motility‐associated marker expression pattern. Finally, the potential to cross extracellular matrix was found to be induced by mTORC1‐activating growth factors and reduced by blocking mTORC1 activity. Taken together, this report provides the first demonstration that human stem cells exhibit mTORC1‐dependent invasive capacity and can concurrently make use of mesenchymal and amoeboid 3D cell migration modes, which represents an important step toward the full biological characterization of fetal human stem cells with relevance to both developmental research and stem cell‐based therapy.

Fetomaternal microchimerism and genetic diagnosis: On the origins of fetal cells and cell-free fetal DNA in the pregnant woman

During pregnancy several types of fetal cells and fetal stem cells, including pregnancy-associated progenitor cells (PAPCs), traffic into the maternal circulation. Whereas they also migrate to various maternal organs and adopt the phenotype of the target tissues to contribute to regenerative processes, fetal cells also play a role in the pathogenesis of maternal diseases. In addition, cell-free fetal DNA (cffDNA) is detectable in the plasma of pregnant women. Together they constitute the well-known phenomenon of fetomaternal microchimerism, which inspired the concept of non-invasive prenatal testing (NIPT) using maternal blood. An in-depth knowledge concerning the origins of these fetal cells and cffDNA allows a more comprehensive understanding of the biological relevance of fetomaternal microchimerism and has implications for the ongoing expansion of resultant clinical applications.

Phenotypical Characterization and Neurogenic Differentiation of Rabbit Adipose Tissue-Derived Mesenchymal Stem Cells

Although the rabbit is a frequently used biological model, the phenotype of rabbit adipose-derived mesenchymal stem cells (rAT-MSCs) is not well characterized. One of the reasons is the absence of specific anti-rabbit antibodies. The study aimed to characterize rAT-MSCs using flow cytometry and PCR methods, especially digital droplet PCR, which confirmed the expression of selected markers at the mRNA level. A combination of these methods validated the expression of MSCs markers (CD29, CD44, CD73, CD90 and CD105). In addition, cells were also positive for CD49f, vimentin, desmin, α-SMA, ALDH and also for the pluripotent markers: NANOG, OCT4 and SOX2. Moreover, the present study proved the ability of rAT-MSCs to differentiate into a neurogenic lineage based on the confirmed expression of neuronal markers ENO2 and MAP2. Obtained results suggest that rAT-MSCs have, despite the slight differences in marker expression, the similar phenotype as human AT-MSCs and possess the neurodifferentiation ability. Accordingly, rAT-MSCs should be subjected to further studies with potential application in veterinary medicine but also, in case of their cryopreservation, as a source of genetic information of endangered species stored in the gene bank.

Placenta-derived mesenchymal stem cells (P-MSCs) for COVID-19 pneumonia-a regenerative dogma

With a robust rise in the number of COVID-19 cases, the World Health Organization (WHO) has declared COVID-19 as a pandemic on 11^th March 2020. COVID-19 pandemic has invited global researchers from various biomedical and biotechnological researchers to plan various treatment modalities for combating this pandemic crisis. At present, there is the unavailability of specific treatment modality; however, researchers have thrown light into the exploration of mesenchymal stem cells (MSCs) to therapeutically perquisite in ameliorating immune-mediated progressive worsening in COVID-19 infected patients. Cellular therapy (CT) has revolutionized the treatment of untreatable diseases with a better clinical and functional outcome. Placenta, being considered as medical waste, contains a variety of stem cells, and hence placenta-derived MSCs (P-MSCs) owe potentiality for extrapolation to combat COVID-19 pandemic. The usage of P-MSCs in combating the COVID-19 pandemic has plausible challenges in terms of isolation, harvesting, expansion, characterization, and involvement of ethical concerns. This article provides an insight into dealing COVID-19 pandemic with P-MSCs as cell-based therapy embracing immunomodulatory and immune-privileged potentials and future prospects. Advocating prospective randomized controlled clinical trials ethically will concretely supplement for its efficacy and safety concerns.

Prophylactic Therapy with Human Amniotic Fluid Stem Cells Improves Long-Term Cognitive Impairment in Rat Neonatal Sepsis Survivors

A systemic inflammatory response induces multiple organ dysfunction and results in poor long-term neurological outcomes in neonatal sepsis. However, there is no effective therapy for treating or preventing neonatal sepsis besides antibiotics and supportive care. Therefore, a novel strategy to improve neonatal sepsis-related morbidity and mortality is desirable. Recently, we reported that prophylactic therapy with human amniotic stem cells (hAFSCs) improved survival in a rat model of lipopolysaccharide (LPS)-induced neonatal sepsis through immunomodulation. Besides improving the mortality, increasing survival without major morbidities is an important goal of neonatal intensive care for neonatal sepsis. This study investigated long-term neurological outcomes in neonatal sepsis survivors treated with hAFSCs using the LPS-induced neonatal sepsis model in rats. We found that prophylactic therapy with hAFSCs improved spatial awareness and memory-based behavior in neonatal sepsis survivors at adolescence in rats. The treatment suppressed acute reactive gliosis and subsequently reduced astrogliosis in the hippocampal region over a long period of assessment. To the best of our knowledge, this is the first report that proves the concept that hAFSC treatment improves cognitive impairment in neonatal sepsis survivors. We demonstrate the efficacy of hAFSC therapy in improving the mortality and morbidity associated with neonatal sepsis.

The effects of human platelet lysate versus commercial endothelial growth medium on the endothelial differentiation potential of human amniotic fluid mesenchymal stem cells

To differentiate stem cells into endothelial cells, vascular endothelia growth factors (VEGF) serve as the major signal for stimulating the cells. However, there are other cytokines or growth factors associated with endothelial cell development and differentiation. Human platelet lysate (hPL) has been a promising reagent in cell-based therapy since it is considered as a source of bioactive molecules and growth factors. The aim of this study was to investigate the in vitro differentiation of human amniotic fluid mesenchymal stem cells (hAF-MSCs) into endothelial-like cells under hPL together with VEGF or endothelial cell growth medium 2 (EGM-2), a commercially induced medium. In this study, hAF-MSCs were isolated from human amniotic fluid cells (hAFCs) using the direct adherence method. The cells expressed CD44, CD73, CD90, and HLA-ABC at high levels and expressed Oct-4 (octamer-binding transcription factor 4) at low levels. The cells were negative for CD31, CD34, CD45, CD105 and HLA-DR. This study found that hAF-MSCs induced with hPL and VEGF had the ability to differentiate into endothelial-like cells by presenting endothelial specific markers (vWF, VEGFR2 and eNOS), forming a network-like structure on Matrigel, and producing nitric oxide (NO). This outcome was similar to those of experiments involving EGM-2 induced cells. The present findings indicate that hPL + VEGF can induce hAF-MSCs to express endothelial cell characteristics. Our findings represent an important step forward in the development of a clinically compliant process for the production of endothelial cell-derived hAF-MSCs, and their subsequent testing in future clinical trials.

Differentiation of cardiomyocyte-like cells from human amniotic fluid mesenchymal stem cells by combined induction with human platelet lysate and 5-azacytidine

Human amniotic fluid mesenchymal stem cells (hAF-MSCs) have been shown to be effective in the treatment of many diseases. Platelet lysate (PL) contains multiple growth and differentiation factors; therefore, it can be used as a differentiation inducer. In this study, we attempted to evaluate the efficiency of human platelet lysate (hPL) on cell viability and the effects on cardiomyogenic differentiation of hAF-MSCs. When treating the cells with hPL, the result showed an increase in cell viability. Expressions of cardiomyogenic specific genes, including GATA4, cTnT, Cx43 and Nkx2.5, were higher in the combined treatment groups of 5-azacytidine (5-aza) and hPL than the expressions of cardiomyogenic specific genes in the control group and in the 5-aza treatment group. In terms of the results of immunofluorescence and immunoenzymatic staining, the highest expressions of cardiomyogenic specific proteins were revealed in combined treatment groups. It can be summarized that hPL may be an effective supporting cardiomyogenic supplementary factor for cardiomyogenic differentiation in hAF-MSCs.

The human amniotic fluid mesenchymal stem cells therapy on, SKOV3, ovarian cancer cell line

Purpose

One of the most common malignancies peculiar to female health with few symptoms, low response to therapy, difficult diagnosis, frequent relapse, and high mortality, is ovarian cancer. Thus, our experiment, using Human amniotic fluid mesenchymal stem cells (hAFMSCs) as a therapeutic tool, aims to find an efficient treatment approach for patients suffering from SKOV3 ovarian cancer.

Material & Methods

In this study, we obtained 5 ml amniotic fluid from 16–20 week pregnant women who underwent amniocentesis for routine prenatal diagnosis by karyotyping in Al‐Zahra Hospital of Tabriz University of Medical Sciences, Iran. Using trans wells in 24 wells plate, hAFMSCs were isolated from all samples, co‐cultured with SKOV3 ovarian cancer cell line, and characterized via flow cytometry and RT‐PCR. Human skin fibroblast cells (HSFCs) were isolated and used as a negative control. SKOV3 and HSFCs' viability after 5 days was evaluated by MTT assay. Cell cycle and apoptotic genes were analyzed by real‐time PCR.

Results

We successfully isolated and characterized hAFMSCs through it positivity for CD44 and CD90 specific mesenchymal stem cell markers and negativity for CD31 and CD45. Oct4 and NANOG were evaluated by RT‐PCR as pluripotency markers, and visualized on 2% gel electrophoresis. We established hAFMS cell lines after 5 days of co‐culturing the SKOV3 cells, viability was decreased; however, HSFCs did not show toxicity by MTT assay. The genes indicated upregulation and high expression by a real‐time PCR.

Conclusions

Our findings showed that hAFMSCs have natural tumor tropism, and can release soluble factors in a cell culture, which cause an efficient anticancer effect. Thus, we can use hAFMSCs for complete anticancer therapy on SKOV3 cell line at cell culture condition and possibly in vivo in the near future.

Amniotic Fluid Cells, Stem Cells, and p53: Can We Stereotype p53 Functions?

In recent years, great interest has been devoted to finding alternative sources for human stem cells which can be easily isolated, ideally without raising ethical objections. These stem cells should furthermore have a high proliferation rate and the ability to differentiate into all three germ layers. Amniotic fluid, ordinarily discarded as medical waste, is potentially such a novel source of stem cells, and these amniotic fluid derived stem cells are currently gaining a lot of attention. However, further information will be required about the properties of these cells before they can be used for therapeutic purposes. For example, the risk of tumor formation after cell transplantation needs to be explored. The tumor suppressor protein p53, well known for its activity in controlling Cell Prolif.eration and cell death in differentiated cells, has more recently been found to be also active in amniotic fluid stem cells. In this review, we summarize the major findings about human amniotic fluid stem cells since their discovery, followed by a brief overview of the important role played by p53 in embryonic and adult stem cells. In addition, we explore what is known about p53 in amniotic fluid stem cells to date, and emphasize the need to investigate its role, particularly in the context of cell tumorigenicity.

Keratinocytes derived from embryonic stem cells induce wound healing in mice

The skin plays an important role in defending the body against the environment. Treatments for burns and skin injuries that use autologous or allogenic skin grafts derived from adult or embryonic stem cells are promising. Embryonic stem cells are candidates for regenerative and reparative medicine. We investigated the utility of keratinocyte-like cells, which are differentiated from mouse embryonic stem cells, for wound healing using a mouse surgical wound model. Mice were allocated to the following groups: experimental, in which dressing and differentiated cells were applied after the surgical wound was created; control, in which only the surgical wound was created; sham, in which only the dressing was applied after the surgical wound was created; and untreated animal controls with healthy skin. Biopsies were taken from each group on days 3, 5 and 7 after cell transfer. Samples were fixed in formalin, then stained with Masson's trichrome and primary antibodies to interleukin-8 (IL-8), fibroblast growth factor-2 (FGF-2), monocyte chemoattractant protein-1 (MCP-1), collagen-1 and epidermal growth factor (EGF) using the indirect immunoperoxidase technique for light microscopy. Wound healing was faster in the experimental group compared to the sham and control groups. The experimental group exhibited increased expression of IL-8, FGF-2 and MCP-1 during early stages of wound healing (inflammation) and collagen-1 and EGF expression during late stages of wound healing (proliferation and remodeling). Keratinocytes derived from embryonic stem cells improved wound healing and influenced the wound healing stages.

Osteoblastic differentiation potential of human amniotic fluid-derived mesenchymal stem cells in different culture conditions

Osteoporosis is a bone degenerative disease characterized by a decrease in bone strength and an alteration in the osseous micro-architecture causing an increase in the risk of fractures. These diseases usually happen in post-menopausal women and elderly men. The most common treatment involves anti-resorptive agent drugs. However, the inhibition of bone resorption alone is not adequate for recovery in patients at the severe stage of osteoporosis who already have a fracture. Therefore, the combination of utilizing osteoblast micro mimetic scaffold in cultivation with the stimulation of osteoblastic differentiations to regain bone formation is a treatment strategy of considerable interest. The aims of this current study are to investigate the osteoblastic differentiation potential of mesenchymal stem cells derived from human amniotic fluid and to compare the monolayer culture and scaffold culture conditions. The results showed the morphology of cells in human amniotic fluid as f-type, which is a typical cell shape of mesenchymal stem cells. In addition, the proliferation rate of cells in human amniotic fluid reached the highest peak after 14 days of culturing. After which time, the growth rate slowly decreased. Moreover, the positive expression of specific mesenchymal cell surface markers including CD44, CD73, CD90, and also HLA-ABC (MHC class I) were recorded. On the other hand, the negative expressions of the endothelial stem cells markers (CD31), the hematopoietic stem cells markers (CD34, 45), the amniotic stem cells markers (CD117), and also the HLA-DR (MHC class II) were also recorded. The expressions of osteoblastogenic related genes including OCN, COL1A1, and ALP were higher in the osteogenic-induced group when compared to the control group. Interestingly, the osteoblastogenic related gene expressions that occurred under scaffold culture conditions were superior to the monolayer culture conditions. Additionally, higher ALP activity and greater calcium deposition were recorded in the extracellular matrix in the osteogenic-induced group than in the culture in the scaffold group. In summary, the mesenchymal stem cells derived from human amniotic fluid can be induced to be differentiated into osteoblastic-like cells and can promote osteoblastic differentiation using the applied scaffold.

IFNα-Expressing Amniotic Fluid-Derived Mesenchymal Stem Cells Migrate to and Suppress HeLa Cell-Derived Tumors in a Mouse Model

Background

Immunotherapy for cervical cancer with type I interferon (IFN) is limited because of the cytotoxicity that accompanies the high doses that are administered. In this study, we investigated the utilization of amniotic fluid-derived mesenchymal stem cells (AF-MSCs) as a means for delivering IFNα to local tumor sites for the suppression of cervical cancer in a mouse model using HeLa cell xenografts.

Methods

The tumor tropism ability of AF-MSCs and AF-MSCs genetically modified to overexpress IFNα (IFNα-AF-MSCs) was examined through Transwell in vitro and through fluorescent images and immunohistochemistry in a mouse model. Tumor size and tumor apoptosis were observed to evaluate the efficacy of the targeting therapy. Mechanistically, tumor cell apoptosis was detected by cytometry and TUNEL, and oncogenic proteins c-Myc, p53, and Bcl-2 as well as microvessel density were detected by immunohistochemistry.

Results

In this model, intravenously injected AF-MSCs selectively migrated to the tumor sites, participated in tumor construction, and promoted tumor growth. After being genetically modified to overexpress IFNα, the IFNα-AF-MSCs maintained their tumor tropism but could significantly suppress tumor growth. The restrictive efficacy of IFNα-AF-MSCs was associated with the suppression of angiogenesis, inhibition of tumor cell proliferation, and induction of apoptosis in tumor cells. Neither AF-MSCs nor IFNα-AF-MSCs trigger tumor formation.

Conclusions

IFNα-AF-MSC-based therapy is feasible and shows potential for treating cervical cancer, suggesting that AF-MSCs may be promising vehicles for delivering targeted anticancer therapy.

Human Adipose-Derived and Amniotic Fluid-Derived Stem Cells: A Preliminary In Vitro Study Comparing Myogenic Differentiation Capability

Background

Around the world, disabilities due to musculoskeletal disorders have increased and are a major health problem worldwide. In recent years, stem cells have been considered to be powerful tools for musculoskeletal tissue engineering. Human adipose-derived stem cells (hADSCs) and amniotic fluid-derived stem cells (hAFSCs) undergo typical differentiation process into cells of mesodermal origin and can be used to treat muscular system diseases. The aim of the present study was to compare the biological characteristic of stem cells isolated from different human tissues (adipose tissue and amniotic fluid) with respect to myogenic capacity and skeletal and smooth muscle differentiation under the same conditions.

Material/Methods

hAFSCs and hADSCs were isolated during standard medical procedures and widely characterized by specific markers expression and differentiation potential. Both cell types were induced toward smooth and striated muscles differentiation, which was assessed with the use of molecular techniques.

Results

For phenotypic characterization, both stem cell types were assessed for the expression of OCT-4, SOX2, CD34, CD44, CD45, and CD90. Muscle-specific markers appeared in both stem cell types, but the proportion of positive cells showed differences depending on the experimental conditions used and the source from which the stem cells were isolated.

Conclusions

In this study, we demonstrated that hADSCs and hAFSCs have different capability of differentiation toward both muscle types. However, hADSCs seem to be a better source for myogenic protocols and can promote skeletal and smooth muscle regeneration through either direct muscle differentiation or by paracrine mechanism.

Biological characterization and pluripotent identification of ovine amniotic fluid stem cells

Mesenchymal stem cells derived from amniotic fluid have become one of the most potential stem cell source for cell-based therapy for the reason they can be harvested at low cost and without ethical problems. Here, we obtained amniotic fluid stem cells (AFSCs) from ovine amniotic fluid and studied the expansion capacity, cell markers expression, karyotype, and multilineage differentiation ability. In our work, AFSCs were subcultured to passage 62. The cell markers, CD29, CD44, CD73 and OCT4 which analyzed by RT-PCR were positive; CD44, CD73, CD90, CD105, NANOG, OCT4 analyzed by immunofluorescence and flow cytometry were also positive. The growth curves of different passages were all typically sigmoidal. The different passages cells took on a normal karyotype. In addition, AFSCs were successfully induced to differentiate into adipocytes, osteoblasts and chondrocytes. The results suggested that the AFSCs isolated from ovine maintained normal biological characteristics and their multilineage differentiation potential provides many potential applications in cell-based therapies and tissue engineering.

Differentiation of mesenchymal stem cells from human amniotic fluid to cardiomyocyte‑like cells

Ischemic heart disease (IHD) is a major factor influencing worldwide mortality rates. Furthermore, IHD has become a significant health problem among the Thai population. Stem cell therapy using mesenchymal stem cells (MSCs) is an alternative therapeutic method that has been applied to improve the quality of life of patients. Amniotic fluid (AF) contains a heterogeneous cell population, including MSCs, which are multipotent stem cells that have the capability to differentiate into mesenchymal lineages. The purpose of the present study was to evaluate the MSC characteristics of human (h)AF and determine its potency regarding cardiogenic differentiation. MSC characterization following flow cytometric analysis revealed that the cells expressed MSC markers, cluster of differentiation (CD)44, CD90, human leukocyte antigen-ABC and CD73. The results of the alamar blue assay demonstrated that cell proliferation rate continuously increased from the early cultivation phase up to 5-fold during days 1 to 5 of cell culturing. The highest rate of cell proliferation was observed on day 17 with a 30-fold increase compared with that on day 1. During the cardiogenic induction stage, morphological changes were observed between day 0 and day 21, and it was revealed that the hAF derived-MSCs in the cardiogenic-induced group exhibited myotube-like morphology after 7 days of cell culturing. Following cardiogenic induction, immunohistochemistry staining was performed on day 21, and reverse transcription-quantitative polymerase chain reaction on day 7 and 21. These steps were performed to detect the protein and gene expression levels of cardiac specific proteins (GATA4, cardiac troponin T, Nkx2.5 and Connexin43). The results of the present study indicated that hAF-MSCs possess the potential to differentiate into cardiomyocyte-like cells. Thus, it was concluded that hAF may be a suitable source of MSCs for stem cell therapy and tissue engineering.

Isolation and characterization of equine endometrial mesenchymal stromal cells

Background

Equine mesenchymal stromal/stem cells (MSCs) are most commonly harvested from bone marrow (BM) or adipose tissue, requiring the use of surgical procedures. By contrast, the uterus can be accessed nonsurgically, and may provide a more readily available cell source. While human endometrium is known to harbor mesenchymal precursor cells, MSCs have not been identified in equine endometrium. This study reports the isolation, culture, and characterization of MSCs from equine endometrium.

Methods

The presence of MSC and pericyte markers in endometrial sections was determined using immunohistochemistry. Stromal cells were harvested and cultured after separation of epithelial cells from endometrial fragments using Mucin-1-bound beads. For comparison, MSCs were also harvested from BM. The expression of surface markers in endometrial and BM-derived MSCs was characterized using flow cytometry and quantitative polymerase chain reaction. MSCs were differentiated in vitro into adipogenic, chondrogenic, osteogenic, and smooth muscle lineages.

Results

Typical markers of MSCs (CD29, CD44, CD90, and CD105) and pericytes (NG2 and CD146) were localized in the equine endometrium. Both endometrial and BM MSCs grew clonally and robustly expressed MSC and pericyte markers in culture while showing greatly reduced or negligible expression of hematopoietic markers (CD45, CD34) and MHC-II. Additionally, both endometrial and BM MSCs differentiated into adipogenic, osteogenic, and chondrogenic lineages in vitro, and endometrial MSCs had a distinct ability to undergo smooth muscle differentiation.

Conclusions

We have demonstrated for the first time the presence of cells in equine endometrium that fulfill the definition of MSCs. The equine endometrium may provide an alternative, easily accessible source of MSCs, not only for therapeutic regeneration of the uterus, but also for other tissues where MSCs from other sources are currently being used therapeutically.

Amniotic fluid stem cell models: A tool for filling the gaps in knowledge for human genetic diseases

Induced pluripotent stem (iPS) cells have attracted attention in recent years as a model of human genetic diseases. Starting from the diseased somatic cells isolated from an affected patient, iPS cells can be created and subsequently differentiated into various cell types that can be used to gain a better understanding of the disease at a cellular and molecular level. There are limitations of iPS cell generation, however, due to low efficiency, high costs, and lengthy protocols. The use of amniotic fluid stem cells (AFS) presents a worthy alternative as a stem cell source for modeling of human genetic diseases. Prenatal identification of chromosomal or Mendelian diseases may require the collection of amniotic fluid which is not only useful for the sake of diagnosis but also from this, AFS cells can be isolated and cultured. Since AFS cells show some characteristics of pluripotency, having the capacity to differentiate into various cell types derived from all three germ layers in vitro, they are a well-suited model for investigations regarding alterations in the molecular biology of a cell due to a specific genetic disease. This readily accessible source of stem cells can replace the necessity for generating iPS cells. Here, we expand on the applicability and importance of AFS cells as a model for discovery in the field of human genetic disease research. This paper is a review article. Referred literature in this paper has been listed in the references section. The data sets supporting the conclusions of this article are available online by searching various databases, including PubMed. Some original points in this article come from the laboratory practice in our research center and the authors’ experiences.

Amniotic fluid as a source of engraftable stem cells

The ability of stem cells to differentiate into various lineages has made them powerful tools of regenerative medicine and applicable to multiple human diseases. Of particular interest, amniotic fluid-derived stem cells (AFSC) have been characterized to express both adult and embryonic cell markers, indicating them as cells within an intermediate stage between embryonic and adult phenotype. AFSC can differentiate into cells of all three germ layers, including hepatic, myogenic, osteogenic, and neurogenic cell types. Furthermore, AFSC have minimal replicative senescence, retaining the ability to divide effectively for over 250 doublings. These facts indicate that amniotic fluid may exist as a promising donor source of stem cells for the treatment of multiple clinically relevant conditions. Of particular interest is the convenience of harvesting stem cells from the amniotic fluid stem for the treatment of newborns, as well as for banking or cryopreserving purposes to be used at a later date. Importantly, the promise of amniotic fluid as a source of stem cells merits ongoing research into their potential therapeutic applications. This paper is a review article. Referred literature in this paper has been listed in the references section. The datasets supporting the conclusions of this article are available online by searching various databases, including PubMed. Some original points in this article come from the laboratory practice in our research center and the authors' experiences.

Differentiation of spontaneously contracting cardiomyocytes from non-virally reprogrammed human amniotic fluid stem cells

Congenital heart defects are the most common birth defect. The limiting factor in tissue engineering repair strategies is an autologous source of functional cardiomyocytes. Amniotic fluid contains an ideal cell source for prenatal harvest and use in correction of congenital heart defects. This study aims to investigate the potential of amniotic fluid-derived stem cells (AFSC) to undergo non-viral reprogramming into induced pluripotent stem cells (iPSC) followed by growth-factor-free differentiation into functional cardiomyocytes. AFSC from human second trimester amniotic fluid were transfected by non-viral vesicle fusion with modified mRNA of OCT4, KLF4, SOX2, LIN28, cMYC and nuclear GFP over 18 days, then differentiated using inhibitors of GSK3 followed 48 hours later by inhibition of WNT. AFSC-derived iPSC had high expression of OCT4, NANOG, TRA-1-60, and TRA-1-81 after 18 days of mRNA transfection and formed teratomas containing mesodermal, ectodermal, and endodermal germ layers in immunodeficient mice. By Day 30 of cardiomyocyte differentiation, cells contracted spontaneously, expressed connexin 43 and β-myosin heavy chain organized in sarcomeric banding patterns, expressed cardiac troponin T and β-myosin heavy chain, showed upregulation of NKX2.5, ISL-1 and cardiac troponin T with downregulation of POU5F1, and displayed calcium and voltage transients similar to those in developing cardiomyocytes. These results demonstrate that cells from human amniotic fluid can be differentiated through a pluripotent state into functional cardiomyocytes.

Highly potent stem cells from full-term amniotic fluid: A realistic perspective

Amniotic fluid (AF) is now known to harbor highly potent stem cells, making it an excellent source for cell therapy. However, most of the stem cells isolated are from AF of mid-term pregnancies in which the collection procedure involves an invasive technique termed amniocentesis. This has limited the access in getting the fluid as the technique imposes certain level of risks to the mother as well as to the fetus. Alternatively, getting AF from full-term pregnancies or during deliveries would be a better resolution. Unfortunately, very few studies have isolated stem cells from AF at this stage of gestation, the fluid that is merely discarded. The question remains whether full-term AF harbors stem cells of similar potency as of the stem cells of mid-term AF. Here, we aim to review the prospect of having this type of stem cells by first looking at the origin and contents of AF particularly during different gestation period. We will then discuss the possibility that the AF, at full term, contains a population of highly potent stem cells. These stem cells are distinct from, and probably more potent than the AF mesenchymal stem cells (AF-MSCs) isolated from full-term AF. By comparing the studies on stem cells isolated from mid-term versus full-term AF from various species, we intend to address the prospect of having highly potent amniotic fluid stem cells from AF of full-term pregnancies in human and animals.

Comparative study on characterization and wound healing potential of goat (Capra hircus) mesenchymal stem cells derived from fetal origin amniotic fluid and adult bone marrow

Caprine amniotic fluid (cAF) and bone marrow cells (cBM) were isolated, expanded and phenotypically characterized by mesenchymal stem cells (MSCs) specific cell surface markers. Both cell types were compared for multilineage differentiation potential by flow cytometry using specific antibodies against lineage specific markers. Furthermore, in vitro expanded cAF-MSCs showed higher expression of trophic factors viz. VEGF and TGF-β1 as compared to cBM-MSCs. Full-skin thickness excisional wounds created on either side of the dorsal midline (thoracolumbar) of New Zealand White rabbits were randomly assigned to subcutaneous injection of either fetal origin cAF-MSCs (n=4) or adult cBM-MSCs (n=4) or sterile PBS (control, n=4). The rate of wound closure was found faster (p<0.05) in cAF-MSCs treated wounds as compared with cBM-MSCs and PBS treated wounds especially on 21st day post-skin excision. Histomorphological examination of the healing tissue showed that wound healing was improved (p<0.05) by greater epithelialization, neovascularization and collagen development in cAF-MSCs as compared to cBM-MSCs and PBS treated wounds.

Amniotic Fluid Stem Cells: A Novel Source for Modeling of Human Genetic Diseases

In recent years, great interest has been devoted to the use of Induced Pluripotent Stem cells (iPS) for modeling of human genetic diseases, due to the possibility of reprogramming somatic cells of affected patients into pluripotent cells, enabling differentiation into several cell types, and allowing investigations into the molecular mechanisms of the disease. However, the protocol of iPS generation still suffers from technical limitations, showing low efficiency, being expensive and time consuming. Amniotic Fluid Stem cells (AFS) represent a potential alternative novel source of stem cells for modeling of human genetic diseases. In fact, by means of prenatal diagnosis, a number of fetuses affected by chromosomal or Mendelian diseases can be identified, and the amniotic fluid collected for genetic testing can be used, after diagnosis, for the isolation, culture and differentiation of AFS cells. This can provide a useful stem cell model for the investigation of the molecular basis of the diagnosed disease without the necessity of producing iPS, since AFS cells show some features of pluripotency and are able to differentiate in cells derived from all three germ layers “in vitro”. In this article, we describe the potential benefits provided by using AFS cells in the modeling of human genetic diseases.

Rapamycin-Induced Hypoxia Inducible Factor 2A Is Essential for Chondrogenic Differentiation of Amniotic Fluid Stem Cells

Amniotic fluid stem (AFS) cells represent a major source of donor cells for cartilage repair. Recently, it became clear that mammalian target of rapamycin (mTOR) inhibition has beneficial effects on cartilage homeostasis, but the effect of mTOR on chondrogenic differentiation is still elusive. Therefore, the objectives of this study were to investigate the effects of mammalian target of rapamycin complex 1 (mTORC1) modulation on the expression of SOX9 and on its downstream targets during chondrogenic differentiation of AFS cells. We performed three-dimensional pellet culturing of AFS cells and of in vitro-expanded, human-derived chondrocytes in the presence of chondrogenic factors. Inhibition of mTORC1 by rapamycin or by small interfering RNA-mediated targeting of raptor (gene name, RPTOR) led to increased AKT activation, upregulation of hypoxia inducible factor (HIF) 2A, and an increase in SOX9, COL2A1, and ACAN abundance. Here we show that HIF2A expression is essential for chondrogenic differentiation and that AKT activity regulates HIF2A amounts. Importantly, engraftment of AFS cells in cell pellets composed of human chondrocytes revealed an advantage of raptor knockdown cells compared with control cells in their ability to express SOX9. Our results demonstrate that mTORC1 inhibition leads to AKT activation and an increase in HIF2A expression. Therefore, we suggest that mTORC1 inhibition is a powerful tool for enhancing chondrogenic differentiation of AFS cells and also of in vitro-expanded adult chondrocytes before transplantation.

SIGNIFICANCE

Repair of cartilage defects is still an unresolved issue in regenerative medicine. Results of this study showed that inhibition of the mammalian target of rapamycin complex 1 (mTORC1) pathway, by rapamycin or by small interfering RNA-mediated targeting of raptor (gene name, RPTOR), enhanced amniotic fluid stem cell differentiation toward a chondrocytic phenotype and increased their engrafting efficiency into cartilaginous structures. Moreover, freshly isolated and in vitro passaged human chondrocytes also showed redifferentiation upon mTORC1 inhibition during culturing. Therefore, this study revealed that rapamycin could enable a more efficient clinical use of cell-based therapy approaches to treat articular cartilage defects.

Mesenchymal Stromal Cells as Cell-Based Therapeutics for Wound Healing

Chronic wounds are a source of substantial morbidity for patients and are a major financial burden for the healthcare system. There are no current therapies that reliably improve nonhealing wounds or reverse pathological scarring. Mesenchymal stromal cells (MSCs) are a promising source of novel cell-based therapies due to the ease of their harvest and their integral role in the native wound repair process. Recent work has addressed the problems of loss of plasticity and off-target delivery through use of modern bioengineering techniques. Here we describe the applications of MSCs harvested from different sources to the wound healing process and recent advances in delivery of MSCs to targeted sites of injury.

A Mini Overview of Isolation, Characterization and Application of Amniotic Fluid Stem Cells

Amniotic fluid represents rich sources of stem cells that can be used in treatments for a wide range of diseases. Amniotic fluid- stem cells have properties intermediate between embryonic and adult mesenchymal stem cells which make them particularly attractive for cellular regeneration and tissue engineering. Furthermore, scientists are interested in these cells because they come from the amniotic fluid that is routinely discarded after birth. In this review we give a brief introduction of amniotic fluid followed by a description of the cells present within this fluid and aim to summarize the all existing isolation methods, culturing, characterization and application of these cells. Finally, we elaborate on the differentiation and potential for these cells to promote regeneration of various tissue defects, including fetal tissue, the nervous system, heart, lungs, kidneys, bones, and cartilage in the form of table.

Molecular signature of amniotic fluid derived stem cells in the fetal sheep model of myelomeningocele

Abnormal cord development results in spinal cord damage responsible for myelomeningocele (MMC). Amniotic fluid-derived stem cells (AFSCs) have emerged as a potential candidate for applications in regenerative medicine. However, their differentiation potential is largely unknown as well as the molecular signaling orchestrating the accurate spinal cord development. Fetal lambs underwent surgical creation of neural tube defect and its subsequent repair. AFSCs were isolated, cultured and characterized at the 12th (induction of MMC), 16th (repair of malformation), and 20th week of gestation (delivery). After performing open hysterectomy, AF collections on fetuses with sham procedures at the same time points as the MMC creation group have been used as controls. Cytological analyses with the colony forming unit assay, XTT and alkaline-phosphatase staining, qRT-PCR gene expression analyses (normalized with aged match controls) and NMR metabolomics profiling were performed. Here we show for the first time the metabolomics and molecular signature variation in AFSCs isolated in the sheep model of MMC, which may be used as diagnostic tools for the in utero identification of the neural tube damage. Intriguingly, PAX3 gene involved in the murine model for spina bifida is modulated in AFSCs reaching the peak of expression at 16 weeks of gestation, 4 weeks after the intervention. Our data strongly suggest that AFSCs reorganize their differentiation commitment in order to generate PAX3-expressing progenitors to counteract the MMC induced in the sheep model. The gene expression signature of AFSCs highlights the plasticity of these cells reflecting possible alterations of embryonic development.

Human Amniotic Fluid Mesenchymal Stem Cells from Second- and Third-Trimester Amniocentesis: Differentiation Potential, Molecular Signature, and Proteome Analysis

Human amniotic fluid stem cells have become an attractive stem cell source for potential applications in regenerative medicine and tissue engineering. The aim of this study was to characterize amniotic fluid-derived mesenchymal stem cells (AF-MSCs) from second- and third-trimester of gestation. Using two-stage protocol, MSCs were successfully cultured and exhibited typical stem cell morphological, specific cell surface, and pluripotency markers characteristics. AF-MSCs differentiated into adipocytes, osteocytes, chondrocytes, myocytes, and neuronal cells, as determined by morphological changes, cell staining, and RT-qPCR showing the tissue-specific gene presence for differentiated cell lineages. Using SYNAPT G2 High Definition Mass Spectrometry technique approach, we performed for the first time the comparative proteomic analysis between undifferentiated AF-MSCs from late trimester of gestation and differentiated into myogenic, adipogenic, osteogenic, and neurogenic lineages. The analysis of the functional and expression patterns of 250 high abundance proteins selected from more than 1400 demonstrated the similar proteome of cultured and differentiated AF-MSCs but the unique changes in their expression profile during cell differentiation that may help the identification of key markers in differentiated cells. Our results provide evidence that human amniotic fluid of second- and third-trimester contains stem cells with multilineage potential and may be attractive source for clinical applications.

Manganese-Enhanced Magnetic Resonance Imaging Enables In Vivo Confirmation of Peri-Infarct Restoration Following Stem Cell Therapy in a Porcine Ischemia-Reperfusion Model

Background

The exact mechanism of stem cell therapy in augmenting the function of ischemic cardiomyopathy is unclear. In this study, we hypothesized that increased viability of the peri-infarct region (PIR) produces restorative benefits after stem cell engraftment. A novel multimodality imaging approach simultaneously assessed myocardial viability (manganese-enhanced magnetic resonance imaging [MEMRI]), myocardial scar (delayed gadolinium enhancement MRI), and transplanted stem cell engraftment (positron emission tomography reporter gene) in the injured porcine hearts.

Methods and Results

Twelve adult swine underwent ischemia–reperfusion injury. Digital subtraction of MEMRI-negative myocardium (intrainfarct region) from delayed gadolinium enhancement MRI–positive myocardium (PIR and intrainfarct region) clearly delineated the PIR in which the MEMRI-positive signal reflected PIR viability. Human amniotic mesenchymal stem cells (hAMSCs) represent a unique population of immunomodulatory mesodermal stem cells that restored the murine PIR. Immediately following hAMSC delivery, MEMRI demonstrated an increased PIR viability signal compared with control. Direct PIR viability remained higher in hAMSC-treated hearts for >6 weeks. Increased PIR viability correlated with improved regional contractility, left ventricular ejection fraction, infarct size, and hAMSC engraftment, as confirmed by immunocytochemistry. Increased MEMRI and positron emission tomography reporter gene signal in the intrainfarct region and the PIR correlated with sustained functional augmentation (global and regional) within the hAMSC group (mean change, left ventricular ejection fraction: hAMSC 85±60%, control 8±10%; P<0.05) and reduced chamber dilatation (left ventricular end-diastole volume increase: hAMSC 24±8%, control 110±30%; P<0.05).

Conclusions

The positron emission tomography reporter gene signal of hAMSC engraftment correlates with the improved MEMRI signal in the PIR. The increased MEMRI signal represents PIR viability and the restorative potential of the injured heart. This in vivo multimodality imaging platform represents a novel, real-time method of tracking PIR viability and stem cell engraftment while providing a mechanistic explanation of the therapeutic efficacy of cardiovascular stem cells.

Rat full term amniotic fluid harbors highly potent stem cells

Amniotic fluid stem cells (AFSCs) are commonly isolated from mid-term amniotic fluid (AF) of animals and human collected via an invasive technique, amniocentesis. Alternatively, AFSCs could be collected at full-term. However, it is unclear whether AFSCs are present in the AF at full term. Here, we aimed to isolate and characterize stem cells isolated from AF of full term pregnant rats. Three stem cell lines have been established following immuno-selection against the stem cell marker, c-kit. Two of the new lines expressed multiple markers of pluripotency until more than passage 90. Further, they spontaneously differentiated into derivatives of the three primary germ layers through the formation of good quality embryoid bodies (EBs), and can be directly differentiated into neural lineage. Their strong stemness and potent neurogenic properties highlight the presence of highly potent stem cells in AF of full-term pregnancies, which could serve as a potential source of stem cells for regenerative medicine.

Amniotic fluid stem cells provide considerable advantages in epidermal regeneration: B7H4 creates a moderate inflammation microenvironment to promote wound repair

The current treatments for severe skin injury all involve skin grafting. However, there is a worldwide shortage of donor skin tissue. In this study, we examined the advantages of using human amniotic fluid stem (hAFS) cells in skin wound healing. In vitro, hAFS cells differentiate into keratinocytes (termed hAFS-K). Like keratinocytes, hAFS-K cells express the markers K5, K14, K10 and involucrin; display typical cellular structure, including a tonofibril-rich cytoplasm; and construct a completely pluristratified epithelium in 3D culture. In vivo, in a mouse excisional wound model, GFP-positive hAFS cells participate in wound repair. Co-localization of GFP/K14 and GFP/K10 in the repaired epidermis demonstrated that hAFS cells can differentiate into keratinocytes. Real-time PCR results confirmed that hAFS cells can initiate and promote early-stage repair of skin damage. During wound repair, hAFS cells did not directly secrete repair-related factors, such as bFGF, VEGF, CXCL12, TGF-β1 and KGF, and provided a moderate inflammation reaction with lower expression of IL-1β, IL-6, TNF-α, Cox2 and Mac3. In hAFS cells, the negative co-stimulatory molecule B7H4 regulates low immunogenicity, which can provide a modest inflammatory reaction microenvironment for wound repair. Furthermore, with their uniquely high proliferation rate, hAFS cells offer a promising alternative for epidermal regeneration.

Intramuscular Transplantation of Pig Amniotic Fluid-Derived Progenitor Cells Has Therapeutic Potential in a Mouse Model of Myocardial Infarction

Acute myocardial infarction (MI) is a fatal event that causes a large number of deaths worldwide. MI results in pathological remodeling and decreased cardiac function, which could lead to heart failure and fatal arrhythmia. Cell therapy is a potential strategy to repair the damage through enhanced angiogenesis or by modulation of the inflammatory process via paracrine signaling. Amniotic fluid-derived progenitor cells (AFPCs) have been reported to differentiate into several lineages and can be used without ethical concerns or risk of teratoma formation. Since pigs are anatomically, physiologically, and genetically similar to humans, and pregnant pigs can be an abundant source of AFPCs, we used porcine AFPCs (pAFPCs) as our target cells. Intramyocardial injection of AFPCs has been shown to cure MI in animal models. However, intramuscular transplantation of cells has not been extensively investigated. In this study, we investigated the therapeutic potential of intramuscular injection of pAFPCs on acute MI. MI mice were divided into 1) PBS control, 2) medium cell dose (1 × 106 cells per leg; cell-M), and 3) high cell dose (4 × 106 cells per leg; cell-H) groups. Cells or PBS were directly injected into the hamstring muscle 20 min after MI surgery. Four weeks after MI surgery, the cell-M and cell-H groups exhibited significantly better ejection fraction, significantly greater wall thickness, smaller infarct scar sizes, and lower LV expansion index compared to the PBS group. Using in vivo imaging, we showed that the hamstring muscles from animals in the cell-M and cell-H groups had RFP-positive signals. In summary, intramuscular injection of porcine AFPCs reduced scar size, reduced pathological remodeling, and preserved heart function after MI.

Upregulation of Nanog and Sox-2 genes following ectopic expression of Oct-4 in amniotic fluid mesenchymal stem cells

Octamer-binding transcription factor 4 (Oct-4), an important gene regulating stem cell pluripotency, is well-known for its ability to reprogram somatic cells in vitro, either alone or in concert with other factors. The aim of this study was to assess the effect of ectopic expression of Oct human amniotic fluid stem cells. We developed a novel method for isolation of putative human amniotic fluid-derived multipotent stem cells. These cells showing mesenchymal stem cell phenotypes (human amniotic fluid-derived mesenchymal stem cells, hAFMSCs) were transfected with a plasmid carrying genes for Oct-4 and the green fluorescent protein (GFP). The stably transfected cells, hAFMSCs-Oct4/GFP, were selected by using G418 and found to express the GFP reporter gene under the control of Oct-4 promoter. We found that hAFMSCs developed by our method possess very high self-renewal ability (about 78 cumulative population doublings) and multilineage differentiation potency. Significantly, the hAFMSCs-Oct4/GFP cells showed enhanced expression of the three major pluripotency genes Oct-4, Nanog, and Sox-2, and increased colony-forming ability and growth rate compared with the parental hAFMSCs. We demonstrated that the ectopic expression of Oct-4 gene in hAFMSCs with high self-renewal ability could upregulate Nanog and Sox-2 gene expression and enhance cell growth rate and colony-forming efficiency. Therefore, the ectopic expression of Oct-4 could be a strategy to develop pluripotency in hAFMSCs for clinical applications.

A comparative study on efficiency of adult fibroblasts and amniotic fluid-derived stem cells as donor cells for production of hand-made cloned buffalo (Bubalus bubalis) embryos

The efficiency of two cell types, namely adult fibroblasts, and amniotic fluid stem (AFS) cells as nuclear donor cells for somatic cell nuclear transfer by hand-made cloning in buffalo (Bubalus bubalis) was compared. The in vitro expanded buffalo adult fibroblast cells showed a typical "S" shape growth curve with a doubling time of 40.8 h and stained positive for vimentin. The in vitro cultured undifferentiated AFS cells showed a doubling time of 33.2 h and stained positive for alkaline phosphatase, these cells were also found positive for undifferentiated embryonic stem cell markers like OCT-4, NANOG and SOX-2, which accentuate their pluripotent property. Further, when AFS cells were exposed to corresponding induction conditions, these cells differentiated into osteogenic, adipogenic and chondrogenic lineages which was confirmed through alizaran, oil red O and alcian blue staining, respectively. Cultured adult fibroblasts and AFS cells of passages 10-15 and 8-12, respectively, were used as nuclear donors. A total of 94 embryos were reconstructed using adult fibroblast as donor cells with cleavage and blastocyst production rate of 62.8 ± 1.8 and 19.1 ± 1.5, respectively. An overall cleavage and blastocyst formation rate of 71.1 ± 1.2 and 29.9 ± 2.2 was obtained when 97 embryos were reconstructed using AFS cells as donor cells. There were no significant differences (P > 0.05) in reconstructed efficiency between the cloned embryos derived from two donor cells, whereas the results showed that there were significant differences (P < 0.05) in cleavage and blastocyst rates between the cloned embryos derived from two donor cell groups. Average total cell numbers for blastocyst generated using AFS cells (172.4 ± 5.8) was significantly (P < 0.05) higher than from adult fibroblasts (148.2 ± 6.1). This study suggests that the in vitro developmental potential of the cloned embryos derived from AFS cells were higher than that of the cloned embryos derived from adult fibroblasts in buffalo hand-made cloning.

Second and third trimester amniotic fluid mesenchymal stem cells can repopulate a de-cellularized lung scaffold and express lung markers

BACKGROUND/PURPOSE

This study examined the potential of amniotic fluid mesenchymal stem cells (AF-MSCs) to generate lung precursor cells in vitro and on a xenologous three-dimensional de-cellularized lung scaffold.

METHODS

AF-MSCs were isolated from human amniotic fluid obtained from 17-37 weeks gestation. Lung differentiation was induced on Matrigel or on de-cellularized rat lungs intra-tracheally injected with AF-MSCs by culturing with a modification of small airway growth medium (mSAGM) lacking retinoic acid (RA) and triodothyronine (T3) with addition of fibroblast growth factor-10 (FGF10). Cells and scaffolds were characterized by immunofluorescence and RT-PCR for markers of viability, proliferation, and lung distal airway differentiation (TTF-1(+) and SPC(+)) in the absence of markers of brain (TuJ1(-)) and thyroid (Pax8(-)).

RESULTS

After culture in mSAGM on either Matrigel or lung scaffolds, there were TTF-1(+)/TuJ1(-)/Pax8(-) cells, indicating a lung precursor phenotype. In addition, SPC(+) cells also evolved suggesting a more mature lung phenotype.

CONCLUSIONS

We demonstrate that mid- to late-trimester AF-MSCs can be induced to develop into lung precursor cells when cultured on the appropriate extracellular matrix (ECM), making them a viable source for use in cell therapy or development of an ex vivo tissue engineered lung.

Human amniotic membrane-derived stromal cells (hAMSC) interact depending on breast cancer cell type through secreted molecules

Human amniotic membrane-derived stromal cells (hAMSC) are candidates for cell-based therapies. We examined the characteristics of hAMSC including the interaction between hAMSC and breast cancer cells, MCF-7, and MDA-MB-231. Human amniotic membrane-derived stromal cells showed typical MSC properties, including fibroblast-like morphology, surface antigen expression, and mesodermal differentiation. To investigate cell-cell interaction via secreted molecules, we cultured breast cancer cells in hAMSC-conditioned medium (hAMSC-CM) and analyzed their proliferation, migration, and secretome profiles. MCF-7 and MDA-MB-231 cells exposed to hAMSC-CM showed increased proliferation and migration. However, in hAMSC-CM, MCF-7 cells proliferated significantly faster than MDA-MB-231 cells. When cultured in hAMSC-CM, MCF-7 cells migrated faster than MDA-MB-231 cells. Two cell types showed different profiles of secreted factors. MCF-7 cells expressed much amounts of IL-8, GRO, and MCP-1 in hAMSC-CM. Human amniotic membrane-derived stromal cells interact with breast cancer cells through secreted molecules. Factors secreted by hAMSCs promote the proliferation and migration of MCF-7 breast cancer cells. For much safe cell-based therapies using hAMSC, it is necessary to study carefully about interaction between hAMSC and cancer cells.