Review: Preclinical studies on placenta-derived cells and amniotic membrane: an update

Therapeutic implication of human placental extract to prevent liver cirrhosis in rats with metabolic dysfunction-associated steatohepatitis

Metabolic dysfunction-associated steatohepatitis (MASH) is always accompanied with hepatic fibrosis that could potentially progress to liver cirrhosis and hepatocellular carcinoma. Employing a rat model, we evaluated the role of human placental extract (HPE) to arrest the progression of hepatic fibrosis to cirrhosis in patients with MASH. SHRSP5/Dmcr rats were fed with a high-fat and high-cholesterol diet for 4 weeks and evaluated for the development of steatosis. The animals were divided into control and treated groups and received either saline or HPE (3.6 ml/kg body weight) subcutaneously thrice a week. A set of animals were killed at the end of 6th, 8th, and 12th weeks from the beginning of the experiment. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), hepatic malondialdehyde (MDA), and glutathione content were measured. Immunohistochemical staining was performed for α-smooth muscle actin (α-SMA), 4-hydroxy-2-nonenal (4-HNE), collagen type I, and type III. Control rats depicted progression of liver fibrosis at 6 weeks, advanced fibrosis and bridging at 8 weeks, and cirrhosis at 12 weeks, which were significantly decreased in HPE-treated animals. Treatment with HPE maintained normal levels of MDA and glutathione in the liver. There was marked decrease in the staining intensity of α-SMA, 4-HNE, and collagen type I and type III in HPE treated rats compared with control animals. The results of the present study indicated that HPE treatment mediates immunotropic, anti-inflammatory, and antioxidant responses and attenuates hepatic fibrosis and early cirrhosis. HPE depicts therapeutic potential to arrest the progression of MASH towards cirrhosis.

Perinatal Stem Cell Therapy to Treat Type 1 Diabetes Mellitus: A Never-Say-Die Story of Differentiation and Immunomodulation

Human term placenta and other postpartum-derived biological tissues are promising sources of perinatal cells with unique stem cell properties. Among the massive current research on stem cells, one medical focus on easily available stem cells is to exploit them in the design of immunotherapy protocols, in particular for the treatment of chronic non-curable human diseases. Type 1 diabetes is characterized by autoimmune destruction of pancreatic beta cells and perinatal cells can be harnessed both to generate insulin-producing cells for beta cell replenishment and to regulate autoimmune mechanisms via immunomodulation capacity. In this study, the strong points of cells derived from amniotic epithelial cells and from umbilical cord matrix are outlined and their potential for supporting cell therapy development. From a basic research and expert stem cell point of view, the aim of this review is to summarize information regarding the regenerative medicine field, as well as describe the state of the art on possible cell therapy approaches for diabetes.

Effect of the Human Amniotic Membrane on the Umbilical Vein Endothelial Cells of Gestational Diabetic Mothers: New Insight on Inflammation and Angiogenesis

One of the most relevant diabetes complications is impaired wound healing, mainly characterized by reduced peripheral blood flow and diminished neovascularization together with increased inflammation and oxidative stress. Unfortunately, effective therapies are currently lacking. Recently, the amniotic membrane (AM) has shown promising results in wound management. Here, the potential role of AM on endothelial cells isolated from the umbilical cord vein of gestational diabetes-affected women (GD-HUVECs), has been investigated. Indeed, GD-HUVECs in vivo exposed to chronic hyperglycemia during pregnancy compared to control cells (C-HUVECs) have shown molecular modifications of cellular homeostasis ultimately impacting oxidative and nitro-oxidative stress, inflammatory phenotype, nitric oxide (NO) synthesis, and bioavailability, thus representing a useful model for studying the mechanisms potentially supporting the role of AM in chronic non-healing wounds. In this study, the anti-inflammatory properties of AM have been assessed using a monocyte–endothelium interaction assay in cells pre-stimulated with tumor necrosis factor-α (TNF-α) and through vascular adhesion molecule expression and membrane exposure, together with the AM impact on the nuclear factor kappa-light-chain-enhancer of activated B cell (NF-kB) pathway and NO bioavailability. Moreover, GD-HUVEC migration and tube formation ability were evaluated in the presence of AM. The results showed that AM significantly reduced TNF-α-stimulated monocyte–endothelium interaction and the membrane exposure of the endothelial vascular and intracellular adhesion molecules (VCAM-1 and ICAM-1, respectively) in both C- and GD-HUVECs. Strikingly, AM treatment significantly improved vessel formation in GD-HUVECs and cell migration in both C- and GD-HUVECs. These collective results suggest that AM positively affects various critical pathways in inflammation and angiogenesis, thus providing further validation for ongoing clinical trials in diabetic foot ulcers.

hAMSC Sheet Promotes Repair of Rabbit Osteochondral Defects

Osteochondral lesion is clinically common disease, which has been recognized as one of the contributing factors of significant morbidity. Although current treatments have achieved good outcomes, some undesirable complications and failures are not uncommon. Cell sheet technology (CST), an innovative technology to harvest seed cells and preserve abundant ECM, has been widely used in various tissue regeneration. For osteochondral lesion, many studies focus on using CST to repair osteochondral lesion and have achieved good outcomes. In the previous study, we have demonstrated that hAMSC sheet had a positive effect on osteochondral lesion. Therefore, this study is aimed at comparing the effect of noninduced hAMSC sheet with chondrogenically induced hAMSC sheet on osteochondral lesion and cartilage regeneration.

Optic Disk Pit Maculopathy Treatment Using a Human Amniotic Membrane Patch: One-Year Results

PURPOSE

To report the 1-year results of human amniotic membrane patch implantation for optic disc pit maculopathy.

DESIGN

A prospective, consecutive, interventional study.

METHODS

Eleven eyes of 11 patients affected by optic disc pit maculopathy associated with subretinal/intraretinal fluid were included in this single-institution study. A 25-gauge pars plana vitrectomy was performed in all cases, with an implant of a human amniotic membrane patch into the optic disc pit and air was injected as endotamponade. The primary study outcome was the subretinal and intraretinal fluid reabsorption. Secondary outcomes were visual acuity improvement and postoperative complications.

RESULTS

Mean central retinal thickness gradually diminished from 512 ± 137 µm to 243 ± 19 µm, at the 12-month follow-up. The mean visual acuity improved from 20/80 at baseline to 20/32 at the 12-month follow-up. Complete fluid resorption occurred in 9 of 11 (81.8%) eyes and there was partial resorption in 2 eyes (18%). No subretinal fluid recurrence was observed during the 12-month follow-up. No intraoperative or postoperative complications were reported during the follow-ups. The amniotic membrane patch remained detectable inside the pit for the entire follow-up time.

CONCLUSION

An amniotic membrane plug may be effective for improving optic disc pit maculopathy. All cases had an anatomical improvement and encouraging visual acuity recovery.

Using of Amniotic Membrane Derivatives for the Treatment of Chronic Wounds

Amniotic membrane grafts have some therapeutic potential for wounds healing. Early application of amniotic membrane turned out as beneficial in healing ulcers, burns, and dermal injuries. Since the second half of the 20th century, the autotransplants of amniotic/chorion tissue have been also used for the treatment of chronic neuropathic wounds, cornea surface injuries, pterygium and conjunctivochalasis, and dental and neurosurgical applications. The aim of this publication is to prepare a coherent overview of amniotic membrane derivatives use in the field of wound healing and also its efficacy. In total 60 publications and 39 posters from 2000-2020 were examined. In these examined publications of case studies with known study results was an assemblage of 1141 patients, and from this assemblage 977 were successfully cured. In case of posters, the assemblage is 570 patients and 513 successfully cured. From the investigated data it is clear that the treatment efficacy is very high-86% and 90%, respectively. Based on this information the use of the amniotic membrane for chronic wounds can be considered highly effective.

Management of intrauterine adhesions using human amniotic mesenchymal stromal cells to promote endometrial regeneration and repair through Notch signalling

Intrauterine adhesions (IUAs) severely hamper women's reproductive functions. Human amniotic mesenchymal stromal cell (hAMSC) transplantation is effective in treating IUAs. Here, we examined the function of Notch signalling in IUA treatment with hAMSC transplantation. Forty-five Sprague-Dawley female rats were randomly divided into the sham operation, IUA, IUA + E2, IUA + hAMSCs and IUA + hAMSCs + E2 groups. After IUA induction in the rats, hAMSCs promoted endometrial regeneration and repair via differentiation into endometrial epithelial cells. In all groups, the expression of key proteins in Notch signalling was detected in the uterus by immunohistochemistry. The results indicated Notch signalling activation in the hAMSCs and hAMSCs + E2 groups. We could also induce hAMSC differentiation to generate endometrial epithelial cells in vitro. Furthermore, the inhibition of Notch signalling using the AdR-dnNotch1 vector suppressed hAMSC differentiation (assessed by epithelial and mesenchymal marker levels), whereas its activation using the AdR-Jagged1 vector increased differentiation. The above findings indicate Notch signalling mediates the differentiation of hAMSCs into endometrial epithelial cells, thus promoting endometrial regeneration and repair; Notch signalling could have an important function in IUA treatment.

Stem cell-based therapy for ameliorating intrauterine adhesion and endometrium injury

Intrauterine adhesion refers to endometrial repair disorders which are usually caused by uterine injury and may lead to a series of complications such as abnormal menstrual bleeding, recurrent abortion and secondary infertility. At present, therapeutic approaches to intrauterine adhesion are limited due to the lack of effective methods to promote regeneration following severe endometrial injury. Therefore, to develop new methods to prevent endometrial injury and intrauterine adhesion has become an urgent need. For severely damaged endometrium, the loss of stem cells in the endometrium may affect its regeneration. This article aimed to discuss the characteristics of various stem cells and their applications for uterine tissue regeneration.

Current Status on Canine Foetal Fluid and Adnexa Derived Mesenchymal Stem Cells

Effective standards of care treatment guidelines have been developed for many canine diseases. However, a subpopulation of patients is partially or completely refractory to these protocols, so their owners seek novel therapies such as treatments with MSCs. Although in dogs, as with human medicine, the most studied MSCs sources have been bone marrow and adipose tissue, in recent years, many researchers have drawn attention towards alternative sources, such as foetal adnexa and fluid, since they possess many advantages over bone marrow and adipose tissue. Foetal adnexa and fluid could be considered as discarded material; therefore, sampling is non-invasive, inexpensive and free from ethical considerations. Furthermore, MSCs derived from foetal adnexa and fluid preserve some of the characteristics of the primitive embryonic layers from which they originate and seem to present immune-modulatory properties that make them a good candidate for allo- and xenotransplantation. The aim of the present review is to offer an update on the state of the art on canine MSCs derived from foetal adnexa and fluid focusing on the findings in their clinical setting.

Chronic Wound Healing by Amniotic Membrane: TGF-β and EGF Signaling Modulation in Re-epithelialization

The application of amniotic membrane (AM) on chronic wounds has proven very effective at resetting wound healing, particularly in re-epithelialization. Historically, several aspects of AM effect on wound healing have been evaluated using cell models. In keratinocytes, the presence of AM induces the activation of mitogen-activated protein (MAP) kinase and c-Jun N-terminal kinase (JNK) pathways, together with the high expression of c-Jun, an important transcription factor for the progression of the re-epithelialization tongue. In general, the levels of transforming growth factor (TGF)-β present in a wound are critical for the process of wound healing; they are elevated during the inflammation phase and remain high in some chronic wounds. Interestingly, the presence of AM, through epidermal growth factor (EGF) signaling, produces a fine-tuning of the TGF-β signaling pathway that re-conducts the stalled process of wound healing. However, the complete suppression of TGF-β signaling has proven negative for the AM stimulation of migration, suggesting that a minimal amount of TGF-β signaling is required for proper wound healing. Regarding migration machinery, AM contributes to the dynamics of focal adhesions, producing a high turnover and thus speeding up remodeling. This is clear because proteins, such as Paxillin, are activated upon treatment with AM. On top of this, AM also produces changes in the expression of Paxillin. Although we have made great progress in understanding the effects of AM on chronic wound healing, a long way is still ahead of us to fully comprehend its effects.

The potential role of multifunctional human amniotic epithelial cells in pancreatic islet transplantation

Pancreatic islet cell transplantation has proven efficacy as a treatment for type 1 diabetes mellitus, chiefly in individuals who are refractory to conventional insulin replacement therapy. At present its clinical use is restricted, firstly by the limited access to suitable donor organs but also due to factors associated with the current clinical transplant procedure which inadvertently impair the long-term functionality of the islet graft. Of note, the physical, biochemical, inflammatory, and immunological stresses to which islets are subjected, either during pretransplant processing or following implantation are detrimental to their sustained viability, necessitating repeated islet infusions to attain adequate glucose control. Progressive decline in functional beta (β)-cell mass leads to graft failure and the eventual re-instatement of exogenous insulin treatment. Strategies which protect and/or preserve optimal islet function in the peri-transplant period would improve clinical outcomes. Human amniotic epithelial cells (HAEC) exhibit both pluripotency and immune-privilege and are ideally suited for use in replacement and regenerative therapies. The HAEC secretome exhibits trophic, anti-inflammatory, and immunomodulatory properties of relevance to islet graft survival. Facilitated by β-cell supportive 3D cell culture systems, HAEC may be integrated with islets bringing them into close spatial arrangement where they may exert paracrine influences that support β-cell function, reduce hypoxia-induced islet injury, and alter islet alloreactivity. The present review details the potential of multifunctional HAEC in the context of islet transplantation, with a focus on the innate capabilities that may counter adverse events associated with the current clinical transplant protocol to achieve long-term islet graft function.

Effects of Preservation Methods in the Composition of the Placental and Reflected Regions of the Human Amniotic Membrane

The human amniotic membrane (AM) is emerging as an interesting biomaterial for regenerative medicine due to its biological and mechanical proprieties. The beneficial effects of the AM are probably related to its bioactive factors produced by local cells and stored in the stromal matrix. However, the search for a preservation method capable of preserving AM properties remains a challenge. The aim of this study was to evaluate important features of 2 anatomical regions of the human AM (reflected and placental amnion) after different preservation methods. For this purpose, human placentas were harvested and processed for AM isolation and storage at 2 different conditions: room temperature for 18 h in DMEM (fresh AM) and -80°C in DMEM/glycerol solution for 30 days (cryopreserved AM). After the storage period, the structural integrity of the membrane was assessed by histological and Picrosirius polarization analysis, cellular viability analysis was performed using the MTT assay, and the soluble proteins were quantified with the Qubit Protein Assay Kit. Both preservation protocols reduced the cell viability, mainly in the placental amnion region of the AM, but preserved the morphology of epithelial and stromal layers, as well as the organization and distribution of collagen fibers. There was a reduction in soluble proteins only in fresh AM. Importantly, the cryopreserved AM group presented the same concentration as the control group. In conclusion, the cryopreservation using DMEM/glycerol was ideal for preserving the structural integrity and soluble protein content, indicating the feasibility of this method in preserving AM for its use in regenerative medicine.

Improved osteogenic differentiation of human amniotic mesenchymal stem cells on gradient nanostructured Ti surface

Titanium (Ti) and Ti-based alloys are widely used in the manufacture of dental and orthopedic implants. However, how to improve their osteogenic differentiation ability is still a key issue to be resolved. In this study, gradient nanostructured surface (GNS) samples were prepared by surface mechanical grinding treatment, and coarse-grained (CG) samples were obtained by recrystallization annealing, making sure that the two kinds of specimens had similar roughness. Then, human amniotic mesenchymal stem cells (hAMSCs) were cocultured with the two kinds of Ti to investigate the material effects on the cellular functions. The results demonstrated that the grains with size ~56 nm were formed on the surface of the GNS Ti, and the grain size gradually increases from the sample surface to interior. Compared to the CG samples, the GNS ones could make the adhesion effect of the hAMSCs better, and promote the cell proliferation and osteogenic differentiation more significantly, the preliminary mechanism of which might be due to their specific nanostructure, the thicker oxide layer formed on their surface and the enhanced hardness. Our results indicated that the gradient nanostructured Ti materials could enhance both osteogenic differentiation and mechanical properties, which may possess broader applications in bone tissue engineering and clinical implanting.

Characterization and Immunomodulation of Canine Amniotic Membrane Stem Cells

PURPOSE

Amniotic membrane stem cells have a high capacity of proliferation, cell expansion, and plasticity, as well as immunomodulatory properties that contribute to maternal-fetal tolerance. Owing to the lack of research on human amniotic membrane at different gestational stages, the canine model is considered ideal because of its genetic and physiological similarities. We aimed to characterize the canine amniotic membrane (CAM) cell lineage in different gestational stages and evaluate the expression of immunomodulatory genes.

MATERIALS AND METHODS

Twenty CAMs from early (20-30 days) (n=7), mid- (31-45 days) (n=7), and late gestation (46-63 days) (n=6) stages were studied. The cell features were assessed by cell viability tests, growth curve, colony-forming units, in vitro differentiation, cell labeling for different immunophenotypes, and pluripotent potential markers. The cells were subjected to RT-PCR and qPCR analysis to determine the expression of IDO, HGF, EGF, PGE2, and IL-10 genes.

RESULTS

CAM cells exhibited a fibroblastoid morphology and adherence to plastic with an average cell viability of 78.5%. The growth curve indicated a growth peak in the second passage and we obtained an average of 138.2 colonies. Osteogenic, chondrogenic, and adipogenic lineages were confirmed by in vitro differentiation assays. Cellular immunophenotyping experiments confirmed the presence of positive mesenchymal markers (CD90 and CD105) and the low or negative expression of hematopoietic markers (CD45 and CD34). Qualitative analysis of the immunomodulatory functions indicated the expression of the IDO, HGF, EGF5, and PGE2 genes. When stimulated by interferon-gamma, CAM cells exhibited higher IDO levels throughout gestation.

CONCLUSION

The CAMs from different gestational stages presented features consistent with mesenchymal stem cell lineage; better results were observed during the late gestation stage. Therefore, the gestational stage is a key factor that may influence the functionality of therapies when using fetal membrane tissues from different periods of pregnancy.

Characterization of Endocannabinoid System and Interleukin Profiles in Ovine AEC: Cannabinoid Receptors Type-1 and Type-2 as Key Effectors of Pro-Inflammatory Response

Amniotic epithelial cells (AEC) have been proposed as promising clinical candidates for regenerative medicine therapies due to their immunomodulatory capacity. In this context, the endocannabinoid system (ECS) has been identified as mediating the immune-stem cell dialogue, even if no information on AEC is available to date. Therefore, this study was designed to assess whether ECS is involved in tuning the constitutive and lipopolysaccharide (LPS)-induced ovine AEC anti-inflammatory and pro-inflammatory interleukin (IL-10, IL-4, and IL-12) profiles. Firstly, interleukins and ECS expressions were studied at different stages of gestation. Then, the role of cannabinoid receptors 1 and 2 (CB1 and CB2) on interleukin expression and release was investigated in middle stage AEC using selective agonists and antagonists. AEC displayed a degradative more than a synthetic endocannabinoid metabolism during the early and middle stages of gestation. At the middle stage, cannabinoid receptors mediated the balance between pro-inflammatory (IL-12) and anti-inflammatory (IL-4 and IL-10) interleukins. The activation of both receptors mediated an overall pro-inflammatory shift-CB1 reduced the anti-inflammatory and CB2 increased the pro-inflammatory interleukin release, particularly after LPS stimulation. Altogether, these data pave the way for the comprehension of AEC mechanisms tuning immune-modulation, crucial for the development of new AEC-based therapy protocols.

Histologic Evaluations of Xenotransplanted Rabbit Knees by In Vitro-Propagated Human Amniotic Epithelial Cells: A Preclinical Study

OBJECTIVES

Human amniotic epithelial cells have multipotent differentiation capacity and are considered as potential therapeutic cells for clinical use. This study represents the first published report on the evaluation of the safety and clinical feasibility of human amniotic epithelial cells for transplant into knee joints, serving as an initial step for subsequent therapeutic evaluations within arthritis clinics.

MATERIALS AND METHODS

Our experimental design was based on subjecting groups of rabbits as a recipient model for human amniotic epithelial cell transplant into knee joints. Twenty rabbits received 200 μL sterile 0.9% sodium chloride solution containing 1 × 10⁹ human amniotic epithelial cells/knee joint by intra-articular injection. Control groups received cell-free saline into knees, and some animals were not treated. After 10 days of xenotransplant, radiology scans and histologic sections of transplanted and nontrans planted knees were examined and compared. Immunohistochemistry staining was also applied to detect tumor necrosis factor-alpha and interleukin 17 (as inflammatory and immuno-rejection markers) in knee sections.

RESULTS

Similar to results shown in noninjected and saline-injected knees, all treated knees appeared normal, with no signs of acute immunorejection, no microbial colonization, no pain, no allergic reactions, no inflammation, and normal motion. Use of human amniotic epithelial cells appeared safe without risk of immunorejection or tumor formation in the transplanted knee joint.

CONCLUSIONS

Human amniotic epithelial cells can be safely transplanted into knee joints, encouraging a need for complementary research for further therapeutic evaluations of human amniotic epithelial cells for curing arthritis.

Human Amniotic Mesenchymal Stem Cell Sheets Encapsulating Cartilage Particles Facilitate Repair of Rabbit Osteochondral Defects

BACKGROUND

Human amniotic mesenchymal stem cells (hAMSCs) are being widely applied in various fields. Therefore, hAMSCs represent a promising candidate to facilitate cartilage regeneration. Nonetheless, no studies have investigated the application of hAMSC sheets to repair cartilage defects in vivo.

PURPOSE

To evaluate hAMSC sheets encapsulating cartilage particles to promote repair of rabbit osteochondral defects.

STUDY DESIGN

Controlled laboratory study.

METHODS

hAMSC sheets were constructed with passage 3 hAMSCs. The phenotypic and structural characteristics of hAMSC sheets were evaluated by flow cytometry and scanning electron microscopy, respectively. The potential for chondrogenic differentiation of hAMSC sheets was assessed by cartilage-specific marker staining, immunohistochemistry, and mRNA and protein expression (SOX9, COLII, and ACAN). Osteochondral defects (diameter, 3.5 mm; depth, 3 mm) were created in the left patellar grooves of 20 New Zealand White rabbits (female or male). The defects were treated with hAMSC sheet/cartilage particles (n = 5), cartilage particles (n = 5), hAMSC sheets (n = 5), or fibrin glue (n = 5). Macroscopic and histological evaluations of the regenerated tissue were conducted after 3 months. The survival time and differentiation of transplanted hAMSCs in the defect area were evaluated by immunofluorescence.

RESULTS

hAMSC sheets had a multilayered structure, with cells stacked layer by layer. Importantly, hAMSC sheets highly expressed phenotypic markers of mesenchymal stem cells. Cartilage-specific marker staining and immunohistochemistry were positive, and mRNA and protein expression was higher in the chondrogenically induced hAMSC sheet group than in the hAMSC sheet group (P < .05). hAMSC sheet/cartilage particles formed a large amount of hyaline-like cartilage in the defect area. In addition, macroscopic and histological scores were significantly higher than those in the other groups. Integration with surrounding normal cartilage and subchondral bone regeneration in the hAMSC sheet/cartilage particles group were better when compared with the other groups. A large number of human nuclear-specific antigen-positive cells were observed in the defect area of hAMSC sheet/cartilage particles and hAMSC sheet groups. Moreover, some positive cells expressed SOX9.

CONCLUSION

hAMSC sheets encapsulating cartilage particles facilitate osteochondral defect repair.

CLINICAL RELEVANCE

Delivery of cells in the form of a cell sheet in conjunction with cartilage particles provides a novel approach for cell-based cartilage regeneration.

Multipotency of mouse trophoblast stem cells

Background

In a number of disease processes, the body is unable to repair injured tissue, promoting the need to develop strategies for tissue repair and regeneration, including the use of cellular therapeutics. Trophoblast stem cells (TSCs) are considered putative stem cells as they differentiate into other subtypes of trophoblast cells. To identify cells for future therapeutic strategies, we investigated whether TSCs have properties of stem/progenitor cells including self-renewal and the capacity to differentiate into parenchymal cells of fetal organs, in vitro and in vivo.

Methods

TSCs were isolated using anti-CD117 micro-beads, from embryonic day 18.5 placentas. In vitro, CD117⁺ TSCs were cultured, at a limiting dilution in growth medium for the development of multicellular clones and in specialized medium for differentiation into lung epithelial cells, cardiomyocytes, and retinal photoreceptor cells. CD117⁺ TSCs were also injected in utero into lung, heart, and the sub-retinal space of embryonic day 13.5 fetuses, and the organs were harvested for histological assessment after a natural delivery.

Results

We first identified CD117⁺ cells within the labyrinth zone and chorionic basal plate of murine placentas in late pregnancy, embryonic day 18.5. CD117⁺ TSCs formed multicellular clones that remained positive for CD117 in vitro, consistent with self-renewal properties. The clonal cells demonstrated multipotency, capable of differentiating into lung epithelial cells (endoderm), cardiomyocytes (mesoderm), and retinal photoreceptor cells (ectoderm). Finally, injection of CD117⁺ TSCs in utero into lungs, hearts, and the sub-retinal spaces of fetuses resulted in their engraftment on day 1 after birth, and the CD117⁺ TSCs differentiated into lung alveolar epithelial cells, heart cardiomyocytes, and retina photoreceptor cells, corresponding with the organs in which they were injected.

Conclusions

Our findings demonstrate that CD117⁺ TSCs have the properties of stem cells including clonogenicity, self-renewal, and multipotency. In utero administration of CD117⁺ TSCs engraft and differentiate into resident cells of the lung, heart, and retina during mouse development.

Electronic supplementary material

The online version of this article (10.1186/s13287-020-1567-4) contains supplementary material, which is available to authorized users.

Gestational diabetes impacts fetal precursor cell responses with potential consequences for offspring

Fetal programming has been proposed as a key mechanism underlying the association between intrauterine exposure to maternal diabetes and negative health outcomes in offspring. To determine whether gestational diabetes mellitus (GDM) might leave an imprint in fetal precursors of the amniotic membrane and whether it might be related to adverse outcomes in offspring, a prospective case‐control study was conducted, in which amniotic mesenchymal stem cells (AMSCs) and resident macrophages were isolated from pregnant patients, with either GDM or normal glucose tolerance, scheduled for cesarean section. After characterization, functional characteristics of AMSCs were analyzed and correlated with anthropometrical and clinical variables from both mother and offspring. GDM‐derived AMSCs displayed an impaired proliferation and osteogenic potential when compared with control cells, accompanied by superior invasive and chemotactic capacity. The expression of genes involved in the inflammatory response (TNFα, MCP‐1, CD40, and CTSS) was upregulated in GDM‐derived AMSCs, whereas anti‐inflammatory IL‐33 was downregulated. Macrophages isolated from the amniotic membrane of GDM mothers consistently showed higher expression of MCP‐1 as well. In vitro studies in which AMSCs from healthy control women were exposed to hyperglycemia, hyperinsulinemia, and palmitic acid confirmed these results. Finally, genes involved in the inflammatory response were associated with maternal insulin sensitivity and prepregnancy body mass index, as well as with fetal metabolic parameters. These results suggest that the GDM environment could program stem cells and subsequently favor metabolic dysfunction later in life. Fetal adaptive programming in the setting of GDM might have a direct negative impact on insulin resistance of offspring.

Canine amniotic membrane mesenchymal stromal/stem cells: Isolation, characterization and differentiation

The amniotic membrane can be considered as one of the sources of isolation of these cells, since it is found in the fetal maternal interface and has low immunogenicity. Mesenchymal stromal/stem cells (MSCs) have not been identified in canine amniotic membrane (AMC). Therefore, our objective was to isolate, culture, characterize and differentiate cells derived from canine amniotic membrane (AMC) and to verify its immunological and tumorigenic potential. For this, 12 dogs fetuses of each gestational age 32, 43 and 55 days were used, and the isolation and culture of the AMC were performed. We observed that the cells presented fibroblastoid morphology and high confluence even after freezing. We also observed that, when induced, they were able to differentiate into osteogenic, adipogenic, and chondrogenic cells, as well as being CD34- and CD105+. Regarding the immunological markers, we found that IL-1, IL-2, IL-6, IL-10 and MHC II were not expressed, whereas MHC I was expressed. After application of AMC cells in nude mice we can verify that there was no tumor formation. Based on this, we conclude that canine amniotic membrane is a good and accessible source for obtaining MSCs of low immunogenic and tumorigenic potential for veterinary therapeutic applications.

The Immunomodulatory Properties of Amniotic Cells: The Two Sides of the Coin

Among the many cell types useful in developing therapeutic treatments, human amniotic cells from placenta have been proposed as valid candidates. Both human amniotic epithelial and mesenchymal stromal cells, and the conditioned medium generated from their culture, exert multiple immunosuppressive activities. Indeed, they inhibit T and B cell proliferation, suppress inflammatory properties of monocytes, macrophages, dendritic cells, neutrophils, and natural killer cells, while promoting induction of cells with regulatory functions such as regulatory T cells and anti-inflammatory M2 macrophages. These properties have laid the foundation for their use for the treatment of inflammatory-based diseases, and encouraging results have been obtained in different preclinical disease models where exacerbated inflammation is present. Moreover, an immune-privileged status of amniotic cells has been often highlighted. However, even if long-term engraftment of amniotic cells has been reported into immunocompetent animals, only few cells survive after infusion. Furthermore, amniotic cells have been shown to be able to induce immune responses in vivo and, under specific culture conditions, they can stimulate T cell proliferation in vitro. Although immunosuppressive properties are a widely recognized characteristic of amniotic cells, immunogenic and stimulatory activities appear to be less reported, sporadic events. In order to improve therapeutic outcome, the mechanisms responsible for the suppressive versus stimulatory activity need to be carefully addressed. In this review, both the immunosuppressive and immunostimulatory activity of amniotic cells will be discussed.

Placental Stem Cells from Domestic Animals: Translational Potential and Clinical Relevance

The field of regenerative medicine is moving toward clinical practice in veterinary science. In this context, placenta-derived stem cells isolated from domestic animals have covered a dual role, acting both as therapies for patients and as a valuable cell source for translational models. The biological properties of placenta-derived cells, comparable among mammals, make them attractive candidates for therapeutic approaches. In particular, stemness features, low immunogenicity, immunomodulatory activity, multilineage plasticity, and their successful capacity for long-term engraftment in different host tissues after autotransplantation, allo-transplantation, or xenotransplantation have been demonstrated. Their beneficial regenerative effects in domestic animals have been proven using preclinical studies as well as clinical trials starting to define the mechanisms involved. This is, in particular, for amniotic-derived cells that have been thoroughly studied to date. The regenerative role arises from a mutual tissue-specific cell differentiation and from the paracrine secretion of bioactive molecules that ultimately drive crucial repair processes in host tissues (e.g., anti-inflammatory, antifibrotic, angiogenic, and neurogenic factors). The knowledge acquired so far on the mechanisms of placenta-derived stem cells in animal models represent the proof of concept of their successful use in some therapeutic treatments such as for musculoskeletal disorders. In the next future, legislation in veterinary regenerative medicine will be a key element in order to certify those placenta-derived cell-based protocols that have already demonstrated their safety and efficacy using rigorous approaches and to improve the degree of standardization of cell-based treatments among veterinary clinicians.

Amniotic membrane as novel scaffold for human iPSC-derived cardiomyogenesis

Recent approaches of using decellularized organ matrices for cardiac tissue engineering prompted us to culture human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (CMs) on the human amniotic membrane (hAM). Since hAM has been used lately to patch diseased hearts in patients and has shown anti-inflammatory and anti-fibrotic benefits, it qualifies as a cardiac compatible and clinically relevant heart tissue scaffold. The aim of this study was to test the ability of the hAM to support attachment, differentiation, and maturation of hiPSC-derived CMs in vitro. hAMs were prepared from term placenta. An in-house generated hiPSC line was used for CM derivation. hiPSC-derived cardiac progenitors were cultured on the surface of cryopreserved hAMs and in the presence of cytokines promoting cardiac differentiation. CMs grown on hAM and popular basement membrane matrix (BMM) Matrigel™ were compared for the following aspects of cardiac development: the morphology of cardiomyocytes with respect to shape and cellular alignments, levels of cardiac-related gene transcript expression, functionality in terms of spontaneous calcium fluxes and mitochondrial densities and distributions. hAM is biocompatible with hiPSC-derived CMs. hAM increased cardiac transcription regulator and myofibril protein transcript expression, accelerated intracellular calcium transients, and enhanced cellular mitochondrial complexity of its cardiomyocytes in comparison to cardiomyocytes differentiated on Matrigel™. Our data suggests that hAM supports differentiation and improves cardiomyogenesis in comparison to Matrigel™. hAMs are natural, easily and largely available. The method of preparing hAM cardiac sheets described here is simple with potential for clinical transplantation. Graphical abstract A An outline of the differentiation protocol with stage-specific growth factors and culture media used. B Cell fates from pluripotent stem cells to cardiomyocytes during differentiation on the amniotic membrane. C-FPhotomicrographs of cells at various stages of differentiation. Scale bars represent 100 μm.

Immunomodulatory Effects of Placenta-derived Mesenchymal Stem Cells on T Cells by Regulation of FoxP3 Expression

The immunomodulatory effects of mesenchymal stem cells (MSCs) are an important mediator of their therapeutic effects in stem cell therapy and regenerative medicine. The regulation mechanism of MSCs is orchestrated by several factors in both intrinsic and extrinsic events. Recent studies have shown that the dynamic expression of cytokines secreted from MSCs control T cell function and maturation by regulating the expression of FoxP3, which figures prominently in T cell differentiation. However, there is no evidence that placenta-derived mesenchymal stem cells (PD-MSCs) have strong immunomodulatory effects on T cell function and maturation via FoxP3 expression. Therefore, we compared the expression of FoxP3 in activated T cells isolated from peripheral blood and co-cultured with PD-MSCs or bone marrow-derived mesenchymal stem cells (BM-MSCs) and analyzed their effect on T cell proliferation and cytokine profiles. Additionally, we verified the immunomodulatory function of PD-MSCs by siRNA-mediated silencing of FoxP3. MSCs, including PD-MSCs and BM-MSCs, promoted differentiation of naive peripheral blood T cells into CD4+CD25+FoxP3+ regulatory T (Treg) cells. Intriguingly, the population of CD4+CD25+FoxP3+ Treg cells co-cultured with PD-MSCs was significantly expanded in comparison to those co-cultured with BM-MSCs or WI38 cells (p＜0.05, p＜0.001). Dynamic expression patterns of several cytokines, including anti- and pro-inflammatory cytokines and members of the transforming growth factor-beta (TGF-β) family secreted from PD-MSCs according to FoxP3 expression were observed. The results suggest that PD-MSCs have an immunomodulatory effect on T cells by regulating FoxP3 expression.

Induction of chondrogenesis of human placenta-derived mesenchymal stem cells via heparin-grafted human fibroblast derived matrix

Background

Formation of mature and functional articular cartilage is still challenging in cartilage tissue engineering. This study investigates the potential of using heparin-grafted decellularized extracellular matrix (ECM) as a novel growth factor delivery platform towards human placenta-derived mesenchymal stem cells (hPMSCs) chondrogenic differentiation. Human fibroblast-derived extracellular matrix (hFDM) is naturally obtained from in vitro-cultured human lung fibroblasts via a mild decellularization process. hFDM was then conjugated with heparin via N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC) chemistry and subject to transforming growth factor (TGF)-β1 immobilization. Once heparin grafted-hFDM (hFDM-hep) and hPMSCs were co-embedded into collagen gel, they were examined for in vitro and in vivo chondrogenesis of hPMSCs for 4 weeks.

Results

We identified heparin moieties on hFDM via toluidine blue O assay and Fourier transform infrared spectroscopy, respectively. We found out that collagen spheroids containing hFDM-hep and TGF-β1 exhibited a sustained release of growth factor for 28 days in vitro. Chondrogenesis of hPMSCs in vitro was supported by accumulated glycosaminoglycan (GAG) content and upregulated chondrogenic specific markers (collagen II, aggrecan, Sox9). Meanwhile, PKH26 - labeled hPMSCs incorporated collagen with either hFDM or hFDM-hep was pre-conditioned in a chondrogenic media for 3 days and subcutaneously implanted in the back of nude mice for 4 weeks. The implanted collagen spheroids containing both hPMSCs and hFDM-hep retained more viable hPMSCs and showed higher level of chondrogenic differentiation, based on immunostaining of collagen type II over collagen alone or Col/hFDM group. In addition, histological examination showed more positive signals of GAG via Safranin-O staining.

Conclusion

TGF-β1-immobilized hFDM-hep can provide an appropriate microenvironment for chondrogenic differentiation of hPMSCs in 3D collagen spheroid.

Electronic supplementary material

The online version of this article (10.1186/s40824-018-0121-2) contains supplementary material, which is available to authorized users.

Transplantation of Human Amniotic Membrane over the Liver Surface Reduces Hepatic Fibrosis in a Cholestatic Model in Young Rats

Purpose

Biliary atresia precedes liver cirrhosis and liver transplantation. Amniotic membrane (AM) promotes tissue regeneration, inhibits fibrosis, and reduces inflammation. Here, we test amniotic membrane potential as a therapeutic tool against cholestatic liver fibrosis.

Methods

Three groups of rats were used: sham surgery (SS), bile duct ligature (BDL), and bile duct ligature plus human amniotic membrane (BDL + AM). After surgery, animals were sacrificed at different weeks. Biochemical and histopathological analyses of liver tissue were performed. Collagen was expressed as a percentage of total liver tissue area. qPCR was performed to analyse gene expression levels of transforming growth factor-β1 (Tgfb1) and apelin (Apln). Statistical analysis performed considered p < 0.05 was significant.

Results

Groups undergoing BDL developed cholestasis. Biochemical markers from BDL + AM group improved compared to BDL group. Ductular reaction, portal fibrosis, and bile plugs were markedly reduced in the BDL + AM group compared to BDL group. Collagen area in BDL + AM group was statistically decreased compared to BDL group. Finally, expression levels of both Apln and Tgfb1 mRNA were statistically downregulated in BDL + AM group versus BDL group.

Conclusion

AM significantly reduces liver fibrosis in a surgical animal model of cholestasis. Our results suggest that AM may be useful as a therapeutic tool in liver cirrhosis.

Comprehensive characterization of chorionic villi-derived mesenchymal stromal cells from human placenta

BACKGROUND

Studies in which mesenchymal stromal cells (MSC) from the placenta are compared with multiple MSC types from other sources are rare. The chorionic plate of the human placenta is mainly composed of fetal blood vessels embedded in fetal stroma tissue, lined by trophoblastic cells and organized into chorionic villi (CV) structures.

METHODS

We comprehensively characterized human MSC collected from postnatal human chorionic villi of placenta (CV-MSC) by analyzing their growth and proliferation potential, differentiation, immunophenotype, extracellular matrix production, telomere length, aging phenotype, and plasticity.

RESULTS

Immunophenotypic characterization of CV-MSC confirmed the typical MSC marker expression as defined by the International Society for Cellular Therapy. The surface marker profile was consistent with increased potential for proliferation, vascular localization, and early myogenic marker expression. CV-MSC retained multilineage differentiation potential and extracellular matrix remodeling properties. They have undergone reduced telomere loss and delayed onset of cellular senescence as they aged in vitro compared to three other MSC sources. We present evidence that increased human telomerase reverse transcriptase gene expression could not explain the exceptional telomere maintenance and senescence onset delay in cultured CV-MSC. Our in-vitro tumorigenesis detection assay suggests that CV-MSC are not prone to undergo malignant transformation during long-term in-vitro culture. Besides SOX2 expression, no other pluripotency features were observed in early and late passages of CV-MSC.

CONCLUSIONS

Our work brings forward two remarkable characteristics of CV-MSC, the first being their extended life span as a result of delayed replicative senescence and the second being a delayed aged phenotype characterized by improved telomere length maintenance. MSC from human placenta are very attractive candidates for stem cell-based therapy applications.

Conditioned medium derived from rat amniotic epithelial cells confers protection against inflammation, cancer, and senescence

Amniotic epithelial cells (AECs) are a class of fetal stem cells that derives from the epiblast and resides in the amnion until birth. AECs are suitable candidates for regenerative medicine because of the ease of collection, their low immunogenicity and inability to form tumors after transplantation. Even though human AECs have been widely investigated, the fact remains that very little is known about AECs isolated from rat, one of the most common animal models in medical testing. In this study, we showed that rat AECs retained stemness properties and plasticity, expressed the pluripotency markers Sox2, Nanog, and Oct4 and were able to differentiate toward the osteogenic lineage. The addition of conditioned medium collected from rat AECs to lipopolysaccharide-activated macrophages elicited anti-inflammatory properties through a decrease of Tnfa expression and slowed tumor cell proliferation in vitro and in vivo. The senescence-associated secretory phenotype was also significantly lower upon incubation of senescent human IMR-90 fibroblast cells with conditioned medium from rat AECs. These results confirm the potential of AECs in the modulation of inflammatory mechanisms and open new therapeutic possibilities for regenerative medicine and anti-aging therapies as well.

Mesenchymal stem cells seeded on a human amniotic membrane improve liver regeneration and mouse survival after extended hepatectomy

Liver failure remains the leading cause of post-operative mortality after hepatectomy. This study investigated the effect of treatment with allogenic mesenchymal stem cells (MSCs) on survival and liver regeneration 48 hr and 7 days after 80% hepatectomy in C57Bl/6 mice. To optimize their biodistribution, MSCs were grown on acellular human amniotic membranes (HAM) and applied as a patch on the remnant liver. This approach was compared with MSC infusion and HAM patch alone. Hepatectomized mice without any treatment were used as control group. Survival rate was calculated and biological and histopathological parameters were analysed to monitor liver function and regeneration. MSCs grown on HAM retained their ability to proliferate, to differentiate into osteoblasts and adipocytes and to respond to pro-inflammatory stimuli. Extended hepatectomy (80%) led to liver failure that resulted in death within 72 hr in 76% of mice. MSC infusion showed an early but transitory positive effect on survival. MSC/HAM patches stimulated regeneration and significantly improved survival rate (54% vs. 24% in the control group at 7 days). They also decreased the severity of hepatectomy-induced steatosis, suggesting a modulation of lipid metabolism in hepatocytes. MSCs were still present on HAM at Days 2 and 7 posthepatectomy. In conclusion, engineered tissue constructs that combine MSCs and HAM improve survival and liver regeneration after 80% hepatectomy in mice. These encouraging results pave the way to potential clinical application.

Amniotic therapeutic biomaterials in urology: current and future applications

To examine the rationale and applications of amniotic tissue augmentation in urological surgery. Published literature in English-language was reviewed for basic science and clinical use of amniotic or amnion-chorionic tissue in genitourinary tissues. Basic science and animal studies support the likely benefit of clinical applications of amnion-derived tissues in a variety of urologic interventions. The broad number of properties found in amniotic membrane, coupled with its immunologically privileged status presents a number of future applications in the urological surgical realm. These applications are in their clinical infancy and suggest that further studies are warranted to investigate the use of these products in a systematic fashion.

Immunomodulatory Effects of Human Cryopreserved Viable Amniotic Membrane in a Pro-Inflammatory Environment In Vitro

INTRODUCTION

Chronic wounds remain a major clinical challenge. Human cryopreserved viable amniotic membrane (hCVAM) is among the most successful therapies, but the mechanisms of action remain loosely defined. Because proper regulation of macrophage behavior is critical for wound healing with biomaterial therapies, we hypothesized that hCVAM would positively regulate macrophage behavior in vitro, and that soluble factors released from the hCVAM would be important for this effect.

MATERIALS AND METHODS

Primary human pro-inflammatory (M1) macrophages were seeded directly onto intact hCVAM or cultured in separation via transwell inserts (Soluble Factors) in the presence of pro-inflammatory stimuli (interferon-γ and lipopolysaccharide) to simulate the chronic wound environment. Macrophages were characterized after 1 and 6 days using multiplex gene expression analysis of 37 macrophage phenotype- and angiogenesis-related genes via NanoString™, and protein content from conditioned media collected at days 1, 3 and 6 was analyzed via enzyme linked immunosorbent assays.

RESULTS AND DISCUSSION

Gene expression analysis showed that Soluble Factors promoted significant upregulation of pro-inflammatory marker IL1B on day 1 yet downregulation of TNF on day 6 compared to the M1 macrophage control. In contrast, intact hCVAM, which includes both extracellular matrix, viable cells, and soluble factors, promoted downregulation of pro-inflammatory markers TNF, CCL5 and CCR7 on day 1 and endothelial receptor TIE1 on day 6, and upregulation of the anti-inflammatory marker IL10 on day 6 compared to the M1 Control. Other genes related to inflammation and angiogenesis (MMP9, VEGF, SPP1, TGFB1, etc.) were differentially regulated between the Soluble Factors and intact hCVAM groups at both time points, though they were not expressed at significantly different levels compared to the M1 Control. Interestingly, Soluble Factors promoted increased secretion of the proinflammatory cytokine tumor necrosis factor-α (TNF-α), while direct contact with hCVAM inhibited secretion of TNF, relative to the M1 Control. Both Soluble Factors and intact hCVAM inhibited secretion of MMP9 and VEGF, pro-inflammatory proteins that are critical for angiogenesis and remodeling, compared to the M1 Control, with intact hCVAM having a stronger effect.

CONCLUSIONS

In a simulated pro-inflammatory environment, intact hCVAM has distinct anti-inflammatory effects on primary human macrophages, and direct macrophage contact with intact hCVAM is required for these effects. These findings are important for the design of next generation immunomodulatory biomaterials for wound repair and regenerative medicine that may include living cells, soluble factors, or a controlled drug delivery system.

Pleiotropic effects of sphingosine-1-phosphate signaling to control human chorionic mesenchymal stem cell physiology

Chorionic stem cells represent a promising opportunity for regenerative medicine. A deeper understanding of the stimuli that regulate their physiology, could lead to innovative clinical approaches. We revealed the presence of multiple sphingosine-1-phosphate (S1P) receptor isoforms in chorion-derived mesenchymal stem cells (CMSCs). Their activation simultaneously propagated from the plasma membrane through Gi and other heterotrimeric G proteins and further diverged toward extracellular-signal-regulated kinase 1/2 (ERK1/2), p38 and protein kinase D 1. At a functional level, S1P signaling inhibited CMSC migration, while promoting proliferation. Instead, a reduction of cell density was obtained when S1P was combined to treatments that increased cAMP intracellular concentration. Such surprising reduction of cell viability was relatively specific as it was not observed with stromal stem cells from bone marrow. Neither it was observed by activating analogous G proteins with bradykinin nor by inducing cell death via a cAMP-independent pathway. S1P could thus reveal novel keys to improve CMSC differentiation programs acting on cAMP concentration. Furthermore, S1P receptor agonists/antagonists could become instrumental in favoring CMSC engraftment by controlling cell motility.

Immunomodulatory properties of human placental mesenchymal stem/stromal cells

Mesenchymal stem/stromal cells (MSCs) are isolated from various fetal and adult tissues such as bone marrow, adipose tissue, cord blood and placenta. Placental MSCs (pMSCs), the main focus of this review, are relatively new MSC types that are not as intensively studied compared with bone marrow-derived MSCs (BMMSCs). MSCs modulate the immune functions of important immune cells involved in alloantigen recognition and elimination, including antigen presenting cells (APCs), T cells, B cells and natural killer (NK) cells. Clinical trials, both completed and underway, employ MSCs to treat various human immunological diseases, such as multiple sclerosis (MS) and type 1 diabetes. However, the mechanisms that mediate the immunosuppressive effects of pMSCs are still largely unknown, and the safety of pMSC use in clinical settings needs further confirmation. Here, we review the current knowledge of the immunosuppressive properties of placental MSCs.

Human amniotic mesenchymal stromal cell transplantation improves endometrial regeneration in rodent models of intrauterine adhesions

BACKGROUND AIMS

Intrauterine adhesion (IUA) is a common uterine cavity disease characterized by the unsatisfactory regeneration of damaged endometria. Recently, stem cell transplantation has been proposed to promote the recovery process. Here we investigated whether human amniotic mesenchymal stromal cells (hAMSCs), a valuable resource for transplantation therapy, could improve endometrial regeneration in rodent IUA models.

METHODS

Forty female Sprague-Dawley rats were randomly assigned to five groups: normal, sham-operated, mechanical injury, hAMSC transplantation, and negative control group. One week after intervention and transplantation, histological analyses were performed, and immunofluorescent and immunohistochemical expression of cell-specific markers and messenger RNA expression of cytokines were measured.

RESULTS

Thicker endometria, increased gland numbers and fewer fibrotic areas were found in the hAMSC transplantation group compared with the mechanical injury group. Engraftment of hAMSCs was detected by the presence of anti-human nuclear antigen-positive cells in the endometrial glands of the transplantation uteri. Transplantation of hAMSCs significantly decreased messenger RNA levels of pro-inflammatory cytokines (tumor necrosis factor-α and interleukin-1β), and increased those of anti-inflammatory cytokines (basic fibroblast growth factor, and interleukin-6) compared with the injured uterine horns. Immunohistochemical expression of endometrial epithelial cells was revealed in specimens after hAMSC transplantation, whereas it was absent in the mechanically injured uteri.

CONCLUSIONS

hAMSC transplantation promotes endometrial regeneration after injury in IUA rat models, possibly due to immunomodulatory properties. These cells provide a more easily accessible source of stem cells for future research into the impact of cell transplantation on damaged endometria.

Phenotype and multipotency of rabbit (Oryctolagus cuniculus) amniotic stem cells

BACKGROUND

Stem cells are capable of unlimited self-renewal and are able to remain undifferentiated for extended periods of time prior to their differentiation into specific cell lineages. Because of the issues (ethical and religious) involved in the use of embryonic stem cells and the limited plasticity of adult stem cells, an alternative cell source could be foetal stem cells derived from extra-embryonic tissue, which are highly proliferative, grow in vitro and possess interesting immunogenic characteristics. As a result, the amniotic membrane of several species has been studied as an important new source of stem cells.

METHODS

Here, we cultured and characterized mesenchymal progenitor cells derived from the rabbit amniotic membrane, and investigated their differentiation potential. In total, amniotic membranes were collected from eight rabbit foetuses and were isolated by the explant technique. The obtained cells were cultured in DMEM-HIGH glucose and incubated at 37 °C in a humidified atmosphere with 5% CO2.

RESULTS

The cells adhered to the culture plates and showed a high proliferative capacity with fibroblast-like morphologies. The cells showed a positive response for markers for the cytoskeleton, mesenchymal stem cells and proliferation, pluripotency and haematopoietic precursor stem cells. However, the cells were negative for CD45, a marker of haematopoietic cells. Furthermore, the cells had the capacity to be induced to differentiate into osteogenic, adipogenic and chondrogenic lineages. In addition, when the cells were injected into nude mice, we did not observe the formation of tumours.

CONCLUSIONS

In summary, our results demonstrate that multipotent mesenchymal stem cells can be obtained from the rabbit amniotic membrane for possible use in future cell therapy applications.

Fetal Membranes-Derived Stem Cells Microenvironment

Recently, the regenerative medicine has been trying to congregate different areas such as tissue engineering and cellular therapy, in order to offer effective treatments to overcome several human and veterinary medical problems. In this regard, fetal membranes have been proposed as a powerful source for obtainment of multipotent stem cells with low immunogenicity, anti-inflammatory properties and nontumorigenicity properties for the treatment of several diseases, including replacing cells lost due to tissue injuries or degenerative diseases. Morpho-physiological data have shown that fetal membranes, especially the yolk sac and amnion play different functions according to the gestational period, which are direct related to the features of the microenvironment that their cells are subject. The characteristics of the microenvironment affect or controls important cellular events involved with proliferation, division and maintenance of the undifferentiated stage or differentiation, especially acting on the extracellular matrix components. Considering the importance of the microenvironment and the diversity of embryonic and fetal membrane-derived stem cells, this chapter will addressed advances in the isolation, phenotyping, characteristics of the microenvironment, and applications of yolk sac and amniotic membrane-derived stem cells for human and veterinary regenerative medicine.

Biological and biomechanical analysis of two types of mesenchymal stem cells for intervention in chemotherapy-induced ovarian dysfunction

PURPOSE

The study aim was to investigate the biological and biomechanical features of a chemotherapy-induced ovarian dysfunction (CIOD) rat model after intervention with human umbilical cord mesenchymal stem cells (UC-MSCs) and human amniotic mesenchymal stem cells (h-AMSCs), thus providing a biological and biomechanical research basis for clinical treatment.

METHODS

The serum levels of estradiol (E2), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and vascular endothelial growth factor (VEGF) in the rat CIOD models were evaluated on the 14th, 30th, 60th, and 90th day of intervention with h-AMSCs and UC-MSCs. In addition, the ovaries in each group were sampled on the 14th and 90th day of intervention for tissue morphology and tensile testing.

RESULTS

The serum levels of E2, LH, and VEGF in the h-AMSC and UC-MSC groups were greater than in the model group, but the serum FSH level was less than in the model group, and the differences were significant (P < 0.05); the maximum tensile stress and maximum strain in h-AMSC and UC-MSC groups were significantly greater than in the model group (P < 0.05).

CONCLUSIONS

UC-MSC and h-AMSC intervention restored damaged ovarian morphology, elasticity, and toughness to a certain extent, and ovarian function showed some recovery.

Tissue engineering for neurodegenerative diseases using human amniotic membrane and umbilical cord

Regenerative medicine, based on the use of stem cells, scaffolds and growth factors, has the potential to be a good approach for restoring damaged tissues of the central nervous system. This study investigated the use of human amniotic mesenchymal stem cells (hAMSC), human amniotic epithelial stem cells (hAESC), and human Wharton's jelly mesenchymal stem cells (hWJMSC) derived from human umbilical cord as a source of stem cells, and the potential of the human amniotic membrane (HAM) as a scaffold and/or source of growth factors to promote nerve regeneration. The hAMSC and hAESC obtained from HAM and the hWJMSC from umbilical cords were cultured in induction medium to obtain neural-like cells. The morphological differentiation of hAMSC, hAESC and hWJMSC into neural-like cells was evident after 4-5 days, when they acquired an elongated and multipolar shape, and at 21 days, when they expressed neural and glial markers. On other way, the HAM was completely decellularized without affecting the components of the basement membrane or the matrix. Subsequently, hAMSC, hAESC and hWJMSC differentiated into neural-like cells were seeded onto the decellularized HAM, maintaining their morphology. Finally, conditioned media from the HAM allowed proliferation of hAMSC, hAESC and hWJMSC differentiated to neural-like cells. Both HAM and umbilical cord are biomaterials with great potential for use in regenerative medicine for the treatment of neurodegenerative diseases.

Amnion-derived stem cell transplantation: A novel treatment for neurological disorders

In this review, we evaluated the literature reporting the use of amniotic stem cells (ASCs) in regenerative medicine for the treatment of neurological disorders. There is an increasing amount of evidence that indicates the exacerbation of the primary injury by inflammation in neurological disorders characterized by rampant inflammation, thereby increasing damage to the central nervous system (CNS). To address this, we focus on the amnion cells' anti-inflammatory properties, which make their transplantation a promising treatment for these disorders. In addition, we offered insights into new applications of the ASC in the fields of regenerative medicine and tissue engineering.

Amniotic membrane mesenchymal cells-derived factors skew T cell polarization toward Treg and downregulate Th1 and Th17 cells subsets

We previously demonstrated that cells derived from the mesenchymal layer of the human amniotic membrane (hAMSC) and their conditioned medium (CM-hAMSC) modulate lymphocyte proliferation in a dose-dependent manner. In order to understand the mechanisms involved in immune regulation exerted by hAMSC, we analyzed the effects of CM-hAMSC on T-cell polarization towards Th1, Th2, Th17, and T-regulatory (Treg) subsets. We show that CM-hAMSC equally suppresses the proliferation of both CD4⁺ T-helper (Th) and CD8⁺ cytotoxic T-lymphocytes. Moreover, we prove that the CM-hAMSC inhibitory ability affects both central (CD45RO⁺CD62L⁺) and effector memory (CD45RO⁺CD62L⁻) subsets. We evaluated the phenotype of CD4⁺ cells in the MLR setting and showed that CM-hAMSC significantly reduced the expression of markers associated to the Th1 (T-bet⁺CD119⁺) and Th17 (RORγt⁺CD161⁺) populations, while having no effect on the Th2 population (GATA3⁺CD193⁺/GATA3⁺CD294⁺cells). T-cell subset modulation was substantiated through the analysis of cytokine release for 6 days during co-culture with alloreactive T-cells, whereby we observed a decrease in specific subset-related cytokines, such as a decrease in pro-inflammatory, Th1-related (TNFα, IFNγ, IL-1β), Th2 (IL-5, IL-6), Th9 (IL-9), and Th17 (IL-17A, IL-22). Furthermore, CM-hAMSC significantly induced the Treg compartment, as shown by an induction of proliferating CD4⁺FoxP3⁺ cells, and an increase of CD25⁺FoxP3⁺ and CD39⁺FoxP3⁺ Treg in the CD4⁺ population. Induction of Treg cells was corroborated by the increased secretion of TGF-β. Taken together, these data strengthen the findings regarding the immunomodulatory properties of CM-hAMSC derived from human amniotic membrane MSC, and in particular provide insights into their effect on regulation of T cell polarization.

Intraperitoneal Injection of Multiplacentas Pooled Cells Treatment on a Mouse Model with Aplastic Anemia

Coinfusion of hematopoietic and mesenchymal stem cells is more effective than hematopoietic stem cell transplantation alone. It is necessary to explore a safe and routine mixed stem cell intraperitoneal transplantation method. Multiplacentas pooled cells were intraperitoneally injected into a radiation- and immunity-induced mouse aplastic anemia model with single time. Then, mouse survival time, peripheral blood hemoglobin count, bone marrow architecture, and donor cell engraftment were assessed. The recipient mouse exhibited donor cell engraftment in both bone marrow and peripheral blood. Survival time and peripheral blood hemoglobin count increased in placenta pooled cells treated mice, compared with model-only controls (P = 0.048 and P = 0.000, resp.). However, placentas pooled cells failed to cause a significant decrease in bone marrow pimelosis area (P = 0.357). Intraperitoneally transplanted multiplacentas pooled cells can survive and engraft into a host body through blood circulation, which can increase the life span of an aplastic anemia model mice, and delay but not abrogate the development of aplastic anemia. Furthermore, they appear to play a role in increasing peripheral blood hemoglobin level response for increasing the life span of aplastic anemia model mice.

Stem cells: a promising source for vascular regenerative medicine

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

The Long Path of Human Placenta, and Its Derivatives, in Regenerative Medicine

In the 1800s, a baby born with a caul, a remnant of the amniotic sack or fetal membranes, was thought to be lucky, special, or protected. Over time, fetal membranes lost their legendary power and were soon considered nothing more than biological waste after birth. However, placenta tissues have reclaimed their potential and since the early 1900s an increasing body of evidence has shown that these tissues have clinical benefits in a wide range of wound repair and surgical applications. Nowadays, there is a concerted effort to understand the mechanisms underlying the beneficial effects of placental tissues, and, more recently, cells derived thereof. This review will summarize the historical and current clinical applications of human placental tissues, and cells isolated from these tissues, and discuss some mechanisms thought to be responsible for the therapeutic effects observed after tissue and/or cell transplantation.

Human amniotic mesenchymal stromal cells (hAMSCs) as potential vehicles for drug delivery in cancer therapy: an in vitro study

INTRODUCTION

In the context of drug delivery, mesenchymal stromal cells (MSCs) from bone marrow and adipose tissue have emerged as interesting candidates due to their homing abilities and capacity to carry toxic loads, while at the same time being highly resistant to the toxic effects. Amongst the many sources of MSCs which have been identified, the human term placenta has attracted particular interest due to its unique, tissue-related characteristics, including its high cell yield and virtually absent expression of human leukocyte antigens and co-stimulatory molecules. Under basal, non-stimulatory conditions, placental MSCs also possess basic characteristics common to MSCs from other sources. These include the ability to secrete factors which promote cell growth and tissue repair, as well as immunomodulatory properties. The aim of this study was to investigate MSCs isolated from the amniotic membrane of human term placenta (hAMSCs) as candidates for drug delivery in vitro.

METHODS

We primed hAMSCs from seven different donors with paclitaxel (PTX) and investigated their ability to resist the cytotoxic effects of PTX, to upload the drug, and to release it over time. We then analyzed whether the uptake and release of PTX was sufficient to inhibit proliferation of CFPAC-1, a pancreatic tumor cell line sensitive to PTX.

RESULTS

For the first time, our study shows that hAMSCs are highly resistant to PTX and are not only able to uptake the drug, but also release it over time. Moreover, we show that PTX is released from hAMSCs in a sufficient amount to inhibit tumor cell proliferation, whilst some of the PTX is also retained within the cells.

CONCLUSION

Taken together, for the first time our results show that placental stem cells can be used as vehicles for the delivery of cytotoxic agents.

In vivo tracking of human placenta derived mesenchymal stem cells in nude mice via ¹⁴C-TdR labeling

Background

In order to shed light on the regenerative mechanism of mesenchymal stem cells (MSCs) in vivo, the bio-distribution profile of implanted cells using a stable and long-term tracking method is needed. We herein investigated the bio-distribution of human placental deciduas basalis derived MSCs (termed as PDB-MSCs) in nude mice after intravenous injection by carbon radioisotope labeling thymidine (¹⁴C-TdR), which is able to incorporate into new DNA strands during cell replication.

Results

The proliferation rate and radioactive emission of human PDB-MSCs after labeled with different concentrations of ¹⁴C-TdR were measured. PDB-MSCs labeled with 1 μCi possessed high radioactivity, and the biological characteristics (i.e. morphology, colony forming ability, differentiation capabilities, karyotype and cell cycle) showed no significant changes after labeling. Thus, 1 μCi was the optimal concentration in this experimental design. In nude mice, 1 × 10⁶¹⁴C-TdR-labeled PDB-MSCs were injected intravenously and the organs were collected at days 1, 2, 3, 5, 30 and 180 after injection, respectively. Radiolabeled PDB-MSCs were found mainly in the lung, liver, spleen, stomach and left femur of the recipient nude mice at the whole observation period.

Conclusions

This work provided solid evidence that ¹⁴C-TdR labeling did not alter the biological characteristics of human placental MSCs, and that this labeling method has potential to decrease the signal from non-infused or dead cells for cell tracking. Therefore, this labeling technique can be utilized to quantify the infused cells after long-term follow-up in pre-clinical studies.