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

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.

Human amniotic fluid mesenchymal stem cells attenuate pancreatic cancer cell proliferation and tumor growth in an orthotopic xenograft mouse model

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a malignant cancer and chemotherapy ineffectively treats PDAC, leading to the requirement for alternative tumor-targeted treatment. Human amniotic fluid mesenchymal stem cells (hAFMSCs) have been revealed to suppress tumor growth in various cancers and they are a strong candidate for treating PDAC.

METHODS

To evaluate the effects of hAFMSCs on human pancreatic carcinoma cells (PANC1, AsPC1 and BxPC3 cell lines) and the possible mechanism involved, an in vitro cell coculture system was used. A PANC1 orthotopic xenograft mouse model was established and hAFMSCs were injected intravenously at 4 weeks post-xenograft.

RESULTS

An in vitro coculture assay showed that hAFMSCs inhibited PANC1 cell proliferation by inducing S phase cell cycle arrest and increased cell apoptosis in a time-dependent manner. In PANC1 cells, hAFMSCs caused the downregulation of Cyclin A and Cyclin B1 as well as the upregulation of p21 (CDKN1A) at 24 h post coculture. The upregulation of pro-apoptotic factors Caspase-3/-8 and Bax at 24 h post coculture reduced the migration and invasion ability of PANC1 cells through inhibiting the epithelial-mesenchymal transition (EMT) process. In a PANC1 orthotopic xenograft mouse model, a single injection of hAFMSCs showed significant tumor growth inhibition with evidence of the modulation of cell cycle and pro-apoptotic regulatory genes and various genes involved in matrix metallopeptidase 7 (MMP7) signaling-triggered EMT process. Histopathological staining showed lower Ki67 levels in tumors from hAFMSCs-treated mice.

CONCLUSIONS

Our data demonstrated that hAFMSCs strongly inhibit PDAC cell proliferation, tumor growth and invasion, possibly by altering cell cycle arrest and MMP7 signaling-triggered EMT.

Potential effect of amniotic fluid-derived stem cells on hyperoxia-induced pulmonary alveolar injury

Background

With the widespread of Coronavirus Disease 2019 pandemic, in spite of the newly emerging vaccines, mutated strains remain a great obstacle to supportive and preventive measures. Coronavirus 19 survivors continue to face great danger of contacting the disease again. As long as no specific treatment has yet to be approved, a great percentage of patients experience real complications, including among others, lung fibrosis. High oxygen inhalation especially for prolonged periods is per se destructive to the lungs. Nevertheless, oxygen remains the first line support for such patients. In the present study we aimed at investigating the role of amniotic fluid-mesenchymal stem cells in preventing versus treating the hyperoxia-induced lung fibrosis in rats.

Methods

The study was conducted on adult albino rats; 5 pregnant female rats were used as amniotic fluid donors, and 64 male rats were randomly divided into two groups: Control group; where 10 rats were kept in normal atmospheric air then sacrificed after 2 months, and hyperoxia-induced lung fibrosis group, where 54 rats were exposed to hyperoxia (100% oxygen for 6 h/day) in air-tight glass chambers for 1 month, then randomly divided into the following 5 subgroups: Hyperoxia group, cell-free media-treated group, stem cells-prophylactic group, stem cells-treated group and untreated group. Isolation, culture and proliferation of stem cells were done till passage 3. Pulmonary function tests, histological examination of lung tissue under light and electron microscopes, biochemical assessment of oxidative stress, IL-6 and Rho-A levels, and statistical analysis of data were performed. F-test (ANOVA) was used for normally distributed quantitative variables, to compare between more than two groups, and Post Hoc test (Tukey) for pairwise comparisons.

Results

Labelled amniotic fluid-mesenchymal stem cells homed to lung tissue. Stem cells administration in the stem cells-prophylactic group succeeded to maintain pulmonary functions near the normal values with no significant difference between their values and those of the control group. Moreover, histological examination of lung tissues showed that stem cells-prophylactic group were completely protected while stem cells-treated group still showed various degrees of tissue injury, namely; thickened interalveolar septa, atelectasis and interstitial pneumonia. Biochemical studies after stem cells injection also showed decreased levels of RhoA and IL-6 in the prophylactic group and to a lesser extent in the treated group, in addition to increased total antioxidant capacity and decreased malondialdehyde in the stem cells-injected groups.

Conclusions

Amniotic fluid-mesenchymal stem cells showed promising protective and therapeutic results against hyperoxia-induced lung fibrosis as evaluated physiologically, histologically and biochemically.

Potential effect of amniotic fluid-derived stem cells on hyperoxia-induced pulmonary alveolar injury

Background

With the widespread of Coronavirus Disease 2019 pandemic, in spite of the newly emerging vaccines, mutated strains remain a great obstacle to supportive and preventive measures. Coronavirus 19 survivors continue to face great danger of contacting the disease again. As long as no specific treatment has yet to be approved, a great percentage of patients experience real complications, including among others, lung fibrosis. High oxygen inhalation especially for prolonged periods is per se destructive to the lungs. Nevertheless, oxygen remains the first line support for such patients. In the present study we aimed at investigating the role of amniotic fluid-mesenchymal stem cells in preventing versus treating the hyperoxia-induced lung fibrosis in rats.

Methods

The study was conducted on adult albino rats; 5 pregnant female rats were used as amniotic fluid donors, and 64 male rats were randomly divided into two groups: Control group; where 10 rats were kept in normal atmospheric air then sacrificed after 2 months, and hyperoxia-induced lung fibrosis group, where 54 rats were exposed to hyperoxia (100% oxygen for 6 h/day) in air-tight glass chambers for 1 month, then randomly divided into the following 5 subgroups: Hyperoxia group, cell-free media-treated group, stem cells-prophylactic group, stem cells-treated group and untreated group. Isolation, culture and proliferation of stem cells were done till passage 3. Pulmonary function tests, histological examination of lung tissue under light and electron microscopes, biochemical assessment of oxidative stress, IL-6 and Rho-A levels, and statistical analysis of data were performed. F-test (ANOVA) was used for normally distributed quantitative variables, to compare between more than two groups, and Post Hoc test (Tukey) for pairwise comparisons.

Results

Labelled amniotic fluid-mesenchymal stem cells homed to lung tissue. Stem cells administration in the stem cells-prophylactic group succeeded to maintain pulmonary functions near the normal values with no significant difference between their values and those of the control group. Moreover, histological examination of lung tissues showed that stem cells-prophylactic group were completely protected while stem cells-treated group still showed various degrees of tissue injury, namely; thickened interalveolar septa, atelectasis and interstitial pneumonia. Biochemical studies after stem cells injection also showed decreased levels of RhoA and IL-6 in the prophylactic group and to a lesser extent in the treated group, in addition to increased total antioxidant capacity and decreased malondialdehyde in the stem cells-injected groups.

Conclusions

Amniotic fluid-mesenchymal stem cells showed promising protective and therapeutic results against hyperoxia-induced lung fibrosis as evaluated physiologically, histologically and biochemically.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02821-3.

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.

The Therapeutic Potential of Amniotic Fluid-Derived Stem Cells on Busulfan-Induced Azoospermia in Adult Rats

BACKGROUND

Busulfan is an alkylating chemotherapeutic agent that is routinely prescribed for leukemic patients to induce myelo-ablation. However, it also results in azoospermia and infertility in cancer survivors. This research was constructed to explore the possible therapeutic role of amniotic fluid-derived stem cells (AFSCs) in improving busulfan-induced azoospermia in adult rats.

METHODS

Forty two adult male albino rats were randomized into: (1) control group, (2) azoospermia group, (3) spontaneous recovery group, and (4) AFSCs-treated group, in which AFSCs were transplanted through their injection into the testicular efferent ducts. The assessment included a histo-pathological examination of the seminiferous tubules by the light and transmission electron microscopes. Additionally, the confocal laser scanning microscope was used for confirmation of homing of the implanted cells. Moreover, we conducted an immuno-fluorescence study for detection of the proliferating cell nuclear antigen (PCNA) in the spermatogenic cells, epididymal sperm count, and a histo-morphometric study.

RESULTS

AFSCs successfully homed over the basement membrane of the injured seminiferous tubules. They greatly attenuated busulfan-induced degenerative and oxidative changes. They also caused a re-expression of PCNA in the germ cells, leading to resumption of spermatogenesis and re-appearance of spermatozoa.

CONCLUSION

AFSCs could be a promising treatment modality for male infertility induced by chemotherapy, as they possess prominent regenerative, anti-apoptotic, and anti-inflammatory potentials.

Adult Stem Cell Therapy for Premature Ovarian Failure: From Bench to Bedside

Premature ovarian failure (POF) is a devastating condition for women of childbearing age with serious health consequences, including distress, infertility, osteoporosis, autoimmune disorders, ischemic heart disease, and increased mortality. In addition to the mainstay estrogen therapy, stem cell therapy has been tested as the result of rapid progress in cell biology and reprogramming research. We hereby provide a review for the latest research and issues related with stem cell-based therapy for POF, and provide a commentary on various methods for enhancing its effect. Large amount of animal studies have demonstrated an extensive benefit of stem cells for failed ovarian recovering. As shown by such studies, stem cell therapy can result in recovery of hormonal levels, follicular activation, ovarian angiogenesis, and functional restoration. Meanwhile, a study of molecular pathways revealed that the function of stem cells mainly depends on their paracrine actions, which can produce multiple factors for the promotion of ovarian angiogenesis and regulation of cellular functions. Nevertheless, studies using disease models also revealed certain drawbacks. Clinical trials have shown that menstrual cycle and even pregnancy may occur in POF patients following transplantation of stem cells, although the limitations, including inadequate number of cases and space for the improvement of transplantation methodology. Only with its safety and effect get substantial improvement through laboratory experiments and clinical trials, can stem cell therapy really bring benefits to more patients. Additionally, effective pretreatment and appropriate transplantation methods for stem cells are also required. Taken together, stem cell therapy has shown a great potential for the reversal of POF and is stepping from bench to bedside. Impact statement Premature ovarian failure (POF) is a devastating condition with serious clinical consequences. The purpose of this review was to summarize the current status of stem cell therapy for POF. Considering the diversity of cell types and functions, a rigorous review is required for the guidance for further research into this field. Meanwhile, the challenges and prospect for clinical application of stem cell treatment, methodological improvements, and innovations are addressed.

Hypoxia-induced amniotic fluid stem cell secretome augments cardiomyocyte proliferation and enhances cardioprotective effects under hypoxic-ischemic conditions

Secretome derived from human amniotic fluid stem cells (AFSC-S) is rich in soluble bioactive factors (SBF) and offers untapped therapeutic potential for regenerative medicine while avoiding putative cell-related complications. Characterization and optimal generation of AFSC-S remains challenging. We hypothesized that modulation of oxygen conditions during AFSC-S generation enriches SBF and confers enhanced regenerative and cardioprotective effects on cardiovascular cells. We collected secretome at 6-hourly intervals up to 30 h following incubation of AFSC in normoxic (21%O₂, nAFSC-S) and hypoxic (1%O₂, hAFSC-S) conditions. Proliferation of human adult cardiomyocytes (hCM) and umbilical cord endothelial cells (HUVEC) incubated with nAFSC-S or hAFSC-S were examined following culture in normoxia or hypoxia. Lower AFSC counts and richer protein content in AFSC-S were observed in hypoxia. Characterization of AFSC-S by multiplex immunoassay showed higher concentrations of pro-angiogenic and anti-inflammatory SBF. hCM demonstrated highest proliferation with 30h-hAFSC-S in hypoxic culture. The cardioprotective potential of concentrated 30h-hAFSC-S treatment was demonstrated in a myocardial ischemia–reperfusion injury mouse model by infarct size and cell apoptosis reduction and cell proliferation increase when compared to saline treatment controls. Thus, we project that hypoxic-generated AFSC-S, with higher pro-angiogenic and anti-inflammatory SBF, can be harnessed and refined for tailored regenerative applications in ischemic cardiovascular disease.

Nonoperative Applications of Placental Tissue Matrix in Orthopaedic Sports Injuries: A Review of Literature

OBJECTIVE

Recently, various amniotic tissue and placental-based tissue matrix (PTM) products have become increasingly available as a nonoperative treatment for tendinopathies and orthopaedic sports injuries. The aim of this review was to evaluate: (1) safety and efficacy of nonoperative use of PTM products, in acute and chronic tendon injuries and (2) the commercially available tissue options to better understand their differences.

DATA SOURCES

A comprehensive literature search was performed. Inclusion criteria were studies reporting on: (1) nonoperative uses of PTM therapy in sports injuries; and (2) clinical outcomes; in (3) human subjects. We excluded: (1) animal studies; (2) basic science studies; (3) non-English language literature; (4) review articles; and (5) duplicate studies. In addition, to determine the various product formulations, their tissue contents, and indications for use, we searched publicly available website content, marketing literature, and Food and Drug Administration (FDA) registration documents.

MAIN RESULTS

Current evidence investigated various PTM products for the treatment of various tendon injuries with demonstrated efficacy mainly in the short term with follow-up ranging between 6 weeks and 3 months. In addition, across all studies, no specific adverse events were reported. Substantial differences exist among the currently available products due to variations in their tissue source, formulations, processing methods, method of sterilization, preservation, and storage, indications for use, and FDA regulation.

CONCLUSIONS

Placental- and amniotic membrane-derived tissues seem to be safe for the nonoperative treatment of tendinopathies. However, several factors may affect the efficacy and safety profile of these products, and the orthopaedic surgeons should be aware of the differences.

Investigating the expression of pluripotency-related genes in human amniotic fluid cells: A semi-quantitative comparison between different subpopulations, from primary to cultured amniocytes

Various classifications have been proposed for human amniotic subpopulations, including classification of spindle-shaped (SS) and round-shaped (RS) cells, as well as the more referred triple-category of epithelioid (E-type) cells, amniotic fluid-specific (AF-type) cells and fibroblastoid (F-type) cells. The present study aims to investigate these amniotic subpopulations regarding the expression of some stem cell markers, including OCT4, NANOG, SOX2, C-KIT (CD117), C-MYC, KLF4, and THY1 (CD90). Flow cytometry was performed to characterize the isolated clonal subpopulations for a hematopoietic and a mesenchymal marker using PE-CD31 and FITC-CD90, respectively. A semi-quantitative RT-PCR analysis was carried out on the isolates in the second half of their lifespan when the cells were at the stationary phase of the growth curve. Characterization of isolated cells demonstrated that all clones including both epithelioid and fibroblastoid cells, had mesenchymal, not hematopoietic, lineage. RT-PCR analysis also revealed a higher expression of the target genes in epithelioid cells. Furthermore, the expression pattern of the genes and their correlations were remarkably different between primary- and long term-cultured amniocytes. Taken together, our results showed that the primary-cultured cells express the stemness genes equally, whereas the long term-cultured amniocytes exhibited a highly variable manner in the expression pattern of the genes. Diverse derivation site of amniocytes and individual genetic background can potentially explain the observed variation in the expression level of the target genes. These can also explain why amniocytes differ in many respects observed in our study, including survival rate, plastic adhesion, and growth characteristics.

Bidirectional and Opposite Effects of Naïve Mesenchymal Stem Cells on Tumor Growth and Progression

Cancer has long been considered as a heterogeneous population of uncontrolled proliferation of different transformed cell types. The recent findings concerning tumorigeneses have highlighted the fact that tumors can progress through tight relationships among tumor cells, cellular, and non-cellular components which are present within tumor tissues. In recent years, studies have shown that mesenchymal stem cells (MSCs) are essential components of non-tumor cells within the tumor tissues that can strongly affect tumor development. Several forms of MSCs have been identified within tumor stroma. Naïve (innate) mesenchymal stem cells (N-MSCs) derived from different sources are mostly recruited into the tumor stroma. N-MSCs exert dual and divergent effects on tumor growth through different conditions and factors such as toll-like receptor priming (TLR-priming), which is the primary underlying causes of opposite effects. Moreover, MSCs also have the contrary effects by various molecular mechanisms relying on direct cellto- cell connections and indirect communications through the autocrine, paracrine routes, and tumor microenvironment (TME).

Overall, cell-based therapies will hold great promise to provide novel anticancer treatments. However, the application of intact MSCs in cancer treatment can theoretically cause adverse clinical outcomes. It is essential that to extensively analysis the effective factors and conditions in which underlying mechanisms are adopted by MSCs when encounter with cancer.

The aim is to review the cellular and molecular mechanisms underlying the dual effects of MSCs followed by the importance of polarization of MSCs through priming of TLRs.

Stem cell-based regenerative medicine

Recent developments in the stem cell biology provided new hopes in treatment of diseases and disorders that yet cannot be treated. Stem cells have the potential to differentiate into various cell types in the body during age. These provide new cells for the body as it grows, and replace specialized cells that are damaged. Since mesenchymal stem cells (MSCs) can be easily harvested from the adipose tissue and can also be cultured and expanded in vitro they have become a good target for tissue regeneration. These cells have been widespread used for cell transplantation in animals and also for clinical trials in humans. The purpose of this review is to provide a summary of our current knowledge regarding the important and types of isolated stem cells from different sources of animal models such as horse, pig, goat, dog, rabbit, cat, rat, mice etc. In this regard, due to the widespread use and lot of attention of MSCs, in this review, we will elaborate on use of MSCs in veterinary medicine as well as in regenerative medicine. Based on the studies in this field, MSCs found wide application in treatment of diseases, such as heart failure, wound healing, tooth regeneration etc.

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.

Telomere shortening as a hallmark of stem cell senescence

Stem cells, especially mesenchymal stem cells (MSCs)-based therapies have been greatly attentioned in regenerative medicine through multi-lineage differentiation, self-renewal properties, etc. Despite the above advantages of MSCs, the defined properties of these cells are strongly affected by aging. Thus, the use of MSCs from older donors is lower than younger one, which limits clinical applications in cell therapy. According to the theories of aging, it is determined that aging is most likely caused by telomere shortening and telomere shortening is considered hallmarks of aging. Finding out the most mechanisms of these changes will probably reveal novel therapeutic targets for prolonging human health and for ameliorating age-associated phenotypes. This review focuses on prevalent knowledge about the mechanisms of stem cell senescence by telomere shortening and the molecular mechanism details involved in it.

Human amniotic fluid stem cells (hAFSCs) expressing p21 and cyclin D1 genes retain excellent viability after freezing with (dimethyl sulfoxide) DMSO

Human amniotic fluid stem cells (hAFSCs) have features intermediate between embryonic and adult SCs, can differentiate into lineages of all three germ layers, and do not develop into tumors in vivo. Moreover, hAFSCs can be easily obtained in routine procedures and there is no ethical or legal limitations regarding their use for clinical and experimental applications. The aim of this study was to assess the effect of slow freezing/thawing and two different concentrations of DMSO (10% DMSO + 90% fetal bovine serum [FBS] and 5% DMSO + 95% FBS) on the survival of hAFSCs. hAFSCs were obtained from 5 pregnant women during amniocentesis at 16-22 weeks of gestation. The expression of pluripotency markers (Octamer-binding transcription factor 4 [Oct4] and NANOG) by reverse transcription polymerase chain reaction and cell surface markers (cluster of differentiation [CD31], CD44, CD45, and CD90) by flow cytometry was analyzed before and after the slow-freezing. Cell viability was assessed by trypan blue exclusion or MTT assay. Quantitative mRNA expression of Oct4, NANOG, cyclin D1 and p21 was determined by real-time PCR before and after the slow-freezing. Pluripotency of hAFSCs was confirmed by NANOG and POU5F1 (Oct4) gene expression before and after slow-freezing. All hAFSC cultures were positive for CD44 and CD90. A higher viability of hAFSCs was observed after freezing with 90% FBS + 10% DMSO. There was increased expression of NANOG and decreased expression of POU5F1 gene after freezing, compared to control cells (before freezing). DMSO and the process of freezing did not significantly change the expression of p21 and cyclin D1 genes in hAFSCs. Overall, our results indicate the applicability of slow-freezing and DMSO in cryopreservation of SCs.

Placenta and Placental Derivatives in Regenerative Therapies: Experimental Studies, History, and Prospects

Placental structures, capable to persist in a genetically foreign organism, are a natural model of allogeneic engraftment carrying a number of distinctive properties. In this review, the main features of the placenta and its derivatives such as structure, cellular composition, immunological and endocrine aspects, and the ability to invasion and deportation are discussed. These features are considered from a perspective that determines the placental material as a unique source for regenerative cell therapies and a lesson for immunological tolerance. A historical overview of clinical applications of placental extracts, cells, and tissue components is described. Empirically accumulated data are summarized and compared with modern research. Furthermore, we define scopes and outlooks of application of placental cells and tissues in the rapidly progressing field of regenerative medicine.

The Placenta: Applications in Orthopaedic Sports Medicine

BACKGROUND

Placenta has a long history of use for treating burns and wounds. It is a rich source of collagen and other extracellular matrix proteins, tissue reparative growth factors, and stem cells, including mesenchymal stem cells (MSCs). Recent data show its therapeutic potential for orthopaedic sports medicine indications.

PURPOSE

To provide orthopaedic surgeons with an anatomic description of the placenta, to characterize its cellular composition, and to review the literature reporting the use of placenta-derived cells and placental tissue allografts for orthopaedic sports medicine indications in animal models and in humans.

STUDY DESIGN

Systematic review.

METHODS

Using a total of 63 keyword combinations, the PubMed and MEDLINE databases were searched for published articles describing the use of placental cells and/or tissue for orthopaedic sports medicine indications. Information was collected on placental tissue type, indications, animal model, study design, treatment regimen, safety, and efficacy outcomes. Results were categorized by indication and subcategorized by animal model.

RESULTS

Outcomes for 29 animal studies and 6 human studies reporting the use of placenta-derived therapeutics were generally positive; however, the placental tissue source, clinical indication, and administration route were highly variable across these studies. Fourteen animal studies described the use of placental tissue for tendon injuries, 13 studies for osteoarthritis or articular cartilage injuries, 3 for ligament injuries, and 1 for synovitis. Both placenta-derived culture-expanded cells (epithelial cells or MSCs) and placental tissue allografts were used in animal studies. In all human studies, commercial placental allografts were used. Five of 6 human studies examined the treatment of foot and ankle pathological conditions, and 1 studied the treatment of knee osteoarthritis.

CONCLUSION

A review of the small number of reported studies revealed a high degree of variability in placental cell types, placental tissue preparation, routes of administration, and treatment regimens, which prohibits making any definitive conclusions. Currently, the clinical use of placenta is limited to only commercial placental tissue allografts, as there are no placenta-derived biological drugs approved for the treatment of orthopaedic sports medicine conditions in the United States. However, this review shows that the application of placental cells or tissue allografts appears to be safe and has potential to improve outcomes for orthopaedic sports medicine indications.

Zinc sulfate contributes to promote telomere length extension via increasing telomerase gene expression, telomerase activity and change in the TERT gene promoter CpG island methylation status of human adipose-derived mesenchymal stem cells

The use of mesenchymal stem cells (MSCs) for cell therapy and regenerative medicine has received widespread attention over the past few years, but their application can be complicated by factors such as reduction in proliferation potential, the senescent tendency of the MSCs upon expansion and their age-dependent decline in number and function. It was shown that all the mentioned features were accompanied by a reduction in telomerase activity and telomere shortening. Furthermore, the role of epigenetic changes in aging, especially changes in promoter methylation, was reported. In this study, MSCs were isolated from the adipose tissue with enzymatic digestion. In addition, immunocytochemistry staining and flow cytometric analysis were performed to investigate the cell-surface markers. In addition, alizarin red-S, sudan III, toluidine blue, and cresyl violet staining were performed to evaluate the multi-lineage differentiation of hADSCs. In order to improve the effective application of MSCs, these cells were treated with 1.5 × 10-8 and 2.99 × 10-10 M of ZnSO4 for 48 hours. The length of the absolute telomere, human telomerase reverse transcriptase (hTERT) gene expression, telomerase activity, the investigation of methylation status of the hTERT gene promoter and the percentage of senescent cells were analyzed with quantitative real-time PCR, PCR-ELISA TRAP assay, methylation specific PCR (MSP), and beta-galactosidase (SA-β-gal) staining, respectively. The results showed that the telomere length, the hTERT gene expression, and the telomerase activity had significantly increased. In addition, the percentage of senescent cells had significantly decreased and changes in the methylation status of the CpG islands in the hTERT promoter region under treatment with ZnSO4 were seen. In conclusion, it seems that ZnSO4 as a proper antioxidant could improve the aging-related features due to lengthening of the telomeres, increasing the telomerase gene expression, telomerase activity, decreasing aging, and changing the methylation status of hTERT promoter; it could potentially beneficial for enhancing the application of aged-MSCs.

Bioartificial Kidneys

Purpose of Review

Historically, there have been many advances in the ways in which we treat kidney diseases. In particular, hemodialysis has set the standard for treatment since the early 1960s and continues today as the most common form of treatment for acute, chronic, and end-stage conditions. However, the rising global prevalence of kidney diseases and our limited understanding of their etiologies have placed significant burdens on current clinical management regimens. This has resulted in a desperate need to improve the ways in which we treat the underlying and ensuing causes of kidney diseases for those who are unable to receive transplants.

Recent Findings

One way of possibly addressing these issues is through the use of improved bioartificial kidneys. Bioartificial kidneys provide an extension to conventional artificial kidneys and dialysis systems, by incorporating aspects of living cellular and tissue function, in an attempt to better mimic normal kidneys. Recent advancements in genomic, cellular, and tissue engineering technologies are facilitating the improved design of these systems.

Summary

In this review, we outline various research efforts that have focused on the development of regenerated organs, implantable constructs, and whole bioengineered kidneys, as well as the transitions from conventional dialysis to these novel alternatives. As a result, we envision that these pioneering efforts can one day produce bioartificial renal technologies that can either perform or reintroduce essential function, and thus provide practical options to treat and potentially prevent kidney diseases.

Enhancement of osteogenic differentiation of rat adipose tissue-derived mesenchymal stem cells by zinc sulphate under electromagnetic field via the PKA, ERK1/2 and Wnt/β-catenin signaling pathways

Zinc ion as an essential trace element and electromagnetic fields (EMFs) has been reported to be involved in the regulation of bone metabolism. The aim of this study was to elucidate the effects of zinc sulphate (ZnSO₄) on the osteogenic differentiation of adipose tissue-derived mesenchymal stem cells (ADSCs) in the presence of EMF as a strategy in osteoporosis therapy. Alkaline phophatase (ALP) activity measurement, calcium assay and expression of several osteoblastic marker genes were examined to assess the effect of ZnSO₄ on the osteogenic differentiation of ADSCs under EMF. The expression of cAMP and PKA was evaluated by ELISA. The expression of β-catenin, Wnt1, Wnt3a, low-density lipoprotein receptor-related protein 5 (LRP5) and reduced dickkopf1 (DKK1) genes were used to detect the Wnt/β-catenin pathway. It was found that ZnSO₄, in the presence of EMF, resulted in an increase in the expression of osteogenic genes, ALP activity and calcium levels. EMF, in the presence of ZnSO₄, increased the cAMP level and protein kinase A (PKA) activity. Treatment of ADSCs with (MAPK)/ERK kinase 1/2 inhibitor, or PKA inhibitor, significantly inhibited the promotion of osteogenic markers, indicating that the induction of osteogenesis was dependent on the ERK and PKA signaling pathways. Real-time PCR analysis showed that ZnSO₄, in the presence of EMF, increased the mRNA expressions of β-catenin, Wnt1, Wnt3a, LRP5 and DKK1. In this study, it was shown that 0.432 μg/ml ZnSO₄, in the presence of 50 Hz, 20 mT EMF, induced the osteogenic differentiation of ADSCs via PKA, ERK1/2 and Wnt/β-catenin signaling pathways.

Amniotic fluid-derived stem cells mixed with platelet rich plasma for restoration of rat alveolar bone defect

Stem cells isolated from the amniotic fluid have been shown as a promising candidate for cell therapy and tissue engineering. However, the experimental and preclinical applications of amniotic fluid-derived stem cells (AFSCs) in the very field of maxillofacial bone tissue engineering are still limited. In this study, rat AFSCs were successfully harvested and characterized in vitro. The rat AFSCs showed typical fibroblastoid morphology, stable proliferation activity and multi-differentiation potential. Flow-cytometry analysis demonstrated that these cells were positive for CD29, CD44, and CD90, while negative for hematopoietic markers such as CD34 and CD45. The regenerative performance of AFSCs-premixed with platelet rich plasma (PRP) gel in restoration of alveolar bone defect was further investigated using a modified rat maxillary alveolar defect model. Micro-computer tomography and histological examination showed a superior regenerative capacity of AFSCs-premixed with PRP gel at both 4 and 8 weeks after operation comparing with control groups. Moreover, the implanted AFSCs can survive in the defect site and directly participate in the bone tissue regeneration. Taken together, these results indicated the feasibility of an AFSCs-based alveolar bone tissue engineering strategy for alveolar defect restoration.

The Isolation and Production of the Ready-to-Use Product (the Amniotic Stem Cell Culture) in Accordance with Good Manufacturing Practice Regulations

According to the Committee for Advanced Therapies, amniotic stem cells were classified as an advanced therapy medicinal product. This work aims to standardize the isolation of amniotic stem cells and the selection of the optimal time of transplantation and cell application methods in burn patients according to the guidelines of the Good Manufacturing Practice. The placenta used in the study was sourced during a Cesarean section. The remnants of the amnion preparation were placed in a sterile container and transferred to a class B environment, where the primary cultures began. The highest average number of cells was obtained by tissue homogenization and culture growth on the AmnioGrow medium. The isolation of the pure monoculture should be performed using the antibodies against CD105. On the basis of an analysis of population doubling, the aging of a population, the cells' viability, and the severity of injury, the cells should be used between passages 3 and 6. Significant differences were found in the number and viability of cells that were transferred as a full sheet, depending on the transfer method. To sum up, amniotic cells are a promising source in the treatment of burns and can be used as a hospital exemption.

Rat adipose-derived mesenchymal stem cells aging reduction by zinc sulfate under extremely low frequency electromagnetic field exposure is associated with increased telomerase reverse transcriptase gene expression

Zinc as an essential trace element was reported to be involved in regulation of the growth and aging of cells. In this study, rat adipose-derived mesenchymal stem cells were exposed to extremely low frequency electromagnetic field (ELF-EMF) of 50 Hz and 20 mT to evaluate whether exposure to ELF-EMF in the presence of zinc sulfate (ZnSO₄) affects the telomerase reverse transcriptase (TERT) gene expression and aging in mesenchymal stem cells (MSCs). The cell plates were divided into four groups including group I (control without ZnSO₄ and ELF-EMF exposure); group II (ELF-EMF-exposure without ZnSO₄); group III (ZnSO₄ treatment without ELF-EMF exposure) and group ІV (ELF-EMF exposure with ZnSO₄). In the presence of different concentrations of ZnSO₄, cells viability, TERT gene expression and percentage of senescent cells were evaluated using colorimetric assay, real-time PCR and senescence-associated β-galactosidase activity assay, respectively. In this experiment, cells were exposed to ELF-EMF for 30 min per day for 21 days in the presence and absence of ZnSO₄. The results revealed that ELF-EMF leads to a decrease in the expression of TERT gene and increase in the percentage of senescent cells. However, the ZnSO₄ could significantly increase the TERT gene expression and decrease the aging of ELF-EMF-exposed MSCs. It seems that ZnSO₄ may be a beneficial agent to delay aging of ELF-EMF-exposed MSCs due to the induction of TERT gene expression.

Mesenchymal stem cells protect against the tissue fibrosis of ketamine-induced cystitis in rat bladder

Abuse of the hallucinogenic drug ketamine promotes the development of lower urinary tract symptoms that resemble interstitial cystitis. The pathophysiology of ketamine-induced cystitis (KC) is largely unknown and effective therapies are lacking. Here, using a KC rat model, we show the therapeutic effects of human umbilical cord-blood (UCB)-derived mesenchymal stem cells (MSCs). Daily injection of ketamine to Sprague-Dawley rats for 2-weeks resulted in defective bladder function, indicated by irregular voiding frequency, increased maximum contraction pressure, and decreased intercontraction intervals and bladder capacity. KC bladders were characterized by severe mast-cell infiltration, tissue fibrosis, apoptosis, upregulation of transforming growth factor-β signaling related genes, and phosphorylation of Smad2 and Smad3 proteins. A single administration of MSCs (1 × 10(6)) into bladder tissue not only significantly ameliorated the aforementioned bladder voiding parameters, but also reversed the characteristic histological and gene-expression alterations of KC bladder. Treatment with the antifibrotic compound N-acetylcysteine also alleviated the symptoms and pathological characteristics of KC bladder, indicating that the antifibrotic capacity of MSC therapy underlies its benefits. Thus, this study for the first-time shows that MSC therapy might help to cure KC by protecting against tissue fibrosis in a KC animal model and provides a foundation for clinical trials of MSC therapy.

Isolation, Characterization, Cryopreservation of Human Amniotic Stem Cells and Differentiation to Osteogenic and Adipogenic Cells

Human stem cells and progenitor cells can be used to treat cancer and replace dysfunctional cells within a tissue or organ. The objective of this study was to identify the appropriate cells type in regenerative medicine and targeted therapy. As an alternative to embryonic and bone marrow stem cells, we examined human amniotic fluid stem cells (hAFSCs), one of the potential source of multipotent stem cells isolated from both cell pellet (using single-stage method), and supernatant of human amniotic fluid. Source of isolation and unique property of the cells emphasize that these cells are one of the promising new tools in therapeutic field. Double sources for isolation and availability of the left over samples in diagnostic laboratory at the same time have less legal and ethical concerns compared with embryonic stem cell studies. Cells were isolated, cultured for 18^th passage for 6 months and characterized using qPCR and flow cytometry. Cells showed good proliferative ability in culture condition. The cells successfully differentiated into the adipogenic and osteogenic lineages. Based on these findings, amniotic fluid can be considered as an appropriate and convenient source of human amniotic fluid stem cells. These cells provide potential tools for therapeutic applications in the field of regenerative medicine. To get a better understanding of crosstalk between Oct4/NANOG with osteogenesis and adipogenesis, we used network analysis based on Common Targets algorithm and Common Regulators algorithm as well as subnetwork discovery based on gene set enrichment. Network analysis highlighted the possible role of MIR 302A and MIR let-7g. We demonstrated the high expression of MIR 302A and low expression of MIR let7g in hAFSCs by qPCR.