Human Amniotic Membrane Mesenchymal Stem Research Articles

Investigating the indirect therapeutic effect of hAMSCs utilizing a novel scaffold (PGS-co-PCL/PGC/PPy/Gelatin) in myocardial ischemia-reperfusion-induced renal failure in male Wistar rats

BackgroundMyocardial ischemia-reperfusion (MI/R) occurs due to temporary or permanent interruptions in the coronary and circulatory system, indirectly affecting kidney function through reduced cardiac output for metabolic needs. In this study, the aim was to explore the indirect effects of using human amniotic membrane mesenchymal stem cells (hAMSCs) with the PGS-co-PCL/PGC/PPy/Gelatin scaffold in male rats with renal failure induced by miocardial ischemia-reperfusion. MethodsMI/R injury was induced in 48 male Wistar rats through left anterior descending artery ligation, divided into four groups (n=12); control group, cell group, scaffold group, and celss+scaffold group. Evaluations were conducted at two and thirty days post MI/R injury, encompassing echocardiography, biochemical, inflammatory markers analysis, and histological assessment. ResultsEchocardiographic findings exhibited notable enhancement in ejection fraction, fractional shortening, and stroke volume of treated groups compared to controls after 30 days (P< 0.05). Serum creatinine (P< 0.001) and urea (P< 0.05) levels significantly decreased in the scaffold+cells group) compared to the control group. The treated cells+ scaffold group displayed improved kidney structure, evidenced by larger glomeruli and reduced Bowman's space compared to the control group (P< 0.01). Immunohistochemical analysis indicated reduced TNF-α protein in the scaffold+ cells group (P< 0.05) in contrast to the control group (P< 0.05). Inflammatory factors IL-6, TNF-α, and AKT gene expression in renal tissues were improved in scaffold+ cells-treated animals. ConclusionOur research proposes the combination of hAMSCs and the PGS-co-PCL/PGC/PPy/Gelatin scaffold in MI/R injured rats appears to enhance renal function and reduce kidney inflammation by improving cardiac output.

Phenolated alginate hydrogel induced osteogenic properties of mesenchymal stem cells via Wnt signaling pathway

Osteogenic properties of phenolated alginate (1.2 %) hydrogel containing collagen (0.5 %)/nano-hydroxyapatite (1 %) were studied on human mesenchymal stem cells in vitro. The phenolation rate and physical properties of the hydrogel were assessed using nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), swelling ratio, gelation time, mechanical assay, and degradation rate. The viability of encapsulated cells was monitored on days 7, 14, and 21 using an MTT assay. Osteoblast differentiation was studied using western blotting, and real-time PCR. Using PCR array analysis, the role of the Wnt signaling pathway was also investigated. Data showed that the combination of alginate/collagen/nanohydroxyapatite yielded proper mechanical features. The addition of nanohydroxyapatite, and collagen reduced degradation, swelling rate coincided with increased stiffness. Elasticity and pore size were also diminished. NMR and FTIR revealed suitable incorporation of collagen and nanohydroxyapatite in the structure of alginate. Real-time PCR analysis and western blotting indicated the expression of osteoblast-related genes such as Runx2 and osteocalcin. PCR array revealed the induction of numerous genes related to Wnt signaling pathways during the maturation of human stem cells toward osteoblast-like cells. In vivo data indicated that transplantation of phenolated alginate/collagen/nanohydroxyapatite hydrogel led to enhanced de novo bone formation in rats with critical-sized calvarial defects. Phenolated alginate hydrogel can promote the osteogenic capacity of human amniotic membrane mesenchymal stem cells in the presence of nanohydroxyapatite and collagen via engaging the Wnt signaling pathway.

Intraocular Pressure-Lowering and Retina-Protective Effects of Exosome-Rich Conditioned Media from Human Amniotic Membrane Stem Cells in a Rat Model of Glaucoma.

Glaucoma is one of the most devastating eye diseases, since the disease can develop into blindness and no effective therapeutics are available. Although the exact mechanisms and causes of glaucoma are unknown, increased intraocular pressure (IOP) has been demonstrated to be an important risk factor. Exosomes are lipid nanoparticles secreted from functional cells, including stem cells, and have been found to contain diverse functional molecules that control body function, inhibit inflammation, protect and regenerate cells, and restore damaged tissues. In the present study, exosome-rich conditioned media (ERCMs) were attained via hypoxic culture (2% O2) of human amniotic membrane mesenchymal stem cells (AMMSCs) and amniotic membrane epithelial stem cells (AMESCs) containing 50 times more exosome particles than normoxic culture (20% O2) medium (NCM). The exosome particles in ERCM were confirmed to be 77 nm in mean size and contain much greater amounts of growth factors (GFs) and neurotrophic factors (NFs) than those in NCM. The glaucoma-therapeutic effects of ERCMs were assessed in retinal cells and a hypertonic (1.8 M) saline-induced high-IOP animal model. CM-DiI-labeled AMMSC exosomes were found to readily penetrate the normal and H2O2-damaged retinal ganglion cells (RGCs), and AMMSC-ERCM not only facilitated retinal pigment epithelial cell (RPEC) proliferation but also protected against H2O2- and hypoxia-induced RPEC insults. The IOP of rats challenged with 1.8 M saline increased twice the normal IOP (12-17 mmHg) in a week. However, intravitreal injection of AMMSC-ERCM or AMESC-ERCM (3.9-4.5 × 108 exosomes in 10 μL/eye) markedly recovered the IOP to normal level in 2 weeks, similar to the effect achieved with platelet-derived growth factor-AB (PDGF-AB, 1.5 μg), a reference material. In addition, AMMSC-ERCM, AMESC-ERCM, and PDGF-AB significantly reversed the shrinkage of retinal layers, preserved RGCs, and prevented neural injury in the glaucoma eyes. It was confirmed that stem cell ERCMs containing large numbers of functional molecules such as GFs and NFs improved glaucoma by protecting retinal cells against oxidative and hypoxic injuries in vitro and by recovering IOP and retinal degeneration in vivo. Therefore, it is suggested that stem cell ERCMs could be a promising candidate for the therapy of glaucoma.

Combined Application of Human Amniotic Membrane Mesenchymal Stem Cells and a Modified PGS-co-PCL Film in an Experimental Model of Myocardial Ischemia-Reperfusion Injury.

According to the World Health Organization (WHO), about 3.9 million people die annually of ischemic heart disease (IHD). Several clinical trials have shown that stem cell therapy is a promising therapeutic approach to IHD. Human amniotic membrane mesenchymal stem cells (hAMSCs) positively affect the repair of myocardial ischemia-reperfusion (MI/R) injury by stimulating endogenous repair mechanisms. The differentiated hAMSCs with and without modified PGS-co-PCL film were applied in the myocardium. MI/R injury was induced by ligating the left anterior descending artery in 48 male Wistar rats. The rats were divided into four groups, (n = 12) animals: heart failure (HF) as the control group, HF + MSCs, HF + MSCs + film, and HF + film. Echocardiography was performed 2 and 4weeks after MI/R injury moreover the expression of the VEGF protein was assessed in the rat heart tissue via immunohistochemistry. In vitro, our result shows fantastic cell survival when seeded on film. In vivo, the left ventricle ejection fraction (LEVD), fractional shortening (FS), end-diastolic (EDV), and stroke volume (SV) have been increased and systolic volumes decreased in all treatment groups in comparison with control. Although combination therapy has a more positive effect on hemodynamic parameters, there is no significant difference between HF + MSCs + film with other treatment groups. Also, In the IHC assay, expression of the VEGF protein significantly increased in all intervention groups. The implantation of MSCs and the modified film significantly enhanced the cardiac functional outcome; in this regard, enhancement in cell survival and VEGF expression are involved as underlying mechanisms in which cardiac film and MSCs exert a beneficial effect.

Effective Combination Therapy with Human Amniotic Membrane Mesenchymal Stem Cells and Low-Level Laser Therapy in Wound Healing in Animal Models.

Introduction: Many studies have recognized the importance of new methods in wound healing. This study aims to investigate the healing effects of allograft extra embryonic mesenchymal stem cells (MSCs) with and without low-level diode laser irradiation when grafted into full-thickness skin defects in diabetic animal models. Methods: In this experimental study, in order to make the rats diabetic, we used an intra-peritoneal injection of streptozotocin. Human amniotic membrane derived mesenchymal stem cells (hAMSCs) were irradiated with a low-level diode laser. Two full-thickness excisions were made on the backs of the rats. Next, the rats were divided into the following groups: group 1: low-level laser (LLL) irradiated hAMSCs and group 2: hAMSCs alone transplanted into skin wound. Histopathologic, ultrasound and elasticity evaluations were performed 7, 14 and 21 days after grafting. Results: In the evaluated rats, epithelial formation was on day 7 and increased until day 14. On days 7, 14 and 21, the percentage of epithelial formation in the irradiated cell group was significantly higher than that in the cell group, so that, on day 21, the epithelium in this group completely covered the wound surface while in the control group the wound surface was still not completely covered. In terms of angiogenesis, on day 7, the irradiated cells were significantly lower than the cells. Also, the formation of collagen in the cellular hydrogel group could confirm the effectiveness of amniotic MSCs in collagen production and thus accelerate the wound healing process. In comparison with hAMSCs alone, irradiated hAMSCs increased the thickness and elasticity of the skin. Conclusion: Low-power laser along with MSCs can be effective in improving chronic wound condition in the animal model.

Naïve pluripotent-like characteristics of non-tumorigenic Muse cells isolated from human amniotic membrane

Multilineage-differentiating stress-enduring (Muse) cells are non-tumorigenic pluripotent-like stem cells that exhibit triploblastic differentiation and self-renewability at the single-cell level, and are collectable as pluripotent surface marker SSEA-3(+) from the bone marrow (BM), peripheral blood, and organ connective tissues. SSEA-3(+) cells from human amniotic membrane mesenchymal stem cells (hAMSCs) were compared with hBM-Muse cells. Similar to hBM-Muse cells, hAMSC-SSEA-3(+) cells expressed pluripotency genes (OCT3/4, NANOG, and SOX2), differentiated into triploblastic cells from a single cell, self-renewed, and exhibited non-tumorigenicity. Notably, however, they exhibited unique characteristics not seen in hBM-Muse cells, including higher expression of genes related to germline- and extraembryonic cell-lineages compared with those in hBM-Muse cells in single-cell RNA-sequencing; and enhanced expression of markers relevant to germline- (PRDM14, TFAP2C, and NANOS3) and extraembryonic cell- (CDX2, GCM1, and ID2) lineages when induced by cytokine subsets, suggesting a broader differentiation potential similar to naïve pluripotent stem cells. t-SNE dimensionality reduction and Gene ontology analysis visualized hAMSC-SSEA-3(+) cells comprised a large undifferentiated subpopulation between epithelial- and mesenchymal-cell states and a small mesenchymal subpopulation expressing genes relevant to the placental formation. The AM is easily accessible by noninvasive approaches. These unique cells are a potentially interesting target naïve pluripotent stem cell-like resource without tumorigenicity.

Human Amniotic Membrane Mesenchymal Stem Cell-Synthesized PGE2 Exerts an Immunomodulatory Effect on Neutrophil Extracellular Trap in a PAD-4-Dependent Pathway through EP2 and EP4.

Human amniotic membrane mesenchymal stem cells (hAM-MSC) secrete a myriad of components with immunosuppressive activities. In the present research, we aimed to describe the effect of prostaglandin E2 (PGE2) secreted by hAM-MSCs on neutrophil extracellular trap (NET) release and to characterize the role of its receptors (EP2/EP4) in PAD-4 and NFκB activity in neutrophils. Human peripheral blood neutrophils were ionomycin-stimulated in the presence of hAM-MSC conditioned medium (CM) treated or not with the selective PGE2 inhibitor MF-63, PGE2, EP2/EP4 agonists, and the selective PAD-4 inhibitor GSK-484. NET release, PAD-4, and NFκB activation were analyzed. Ionomycin induced NET release, which was inhibited in the presence of hAM-MSC-CM, while CM from hAM-MSCs treated with MF-63 prevented NET release inhibition. PGE2 and EP2/EP4 agonists, and GSK-484 inhibited NET release. EP2/EP4 agonists and GSK-484 inhibited H3-citrullination but did not affect PAD-4 protein expression. Finally, PGE2 and EP2/EP4 agonists and GSK-484 increased NFκB phosphorylation. Taken together, these results suggest that hAM-MSC exert their immunomodulatory activities through PGE2, inhibiting NET release in a PAD-4-dependent pathway. This research proposes a new mechanism by which hAM-MSC exert their activities when modulating the innate immune response and inhibiting NET release.

Modulation of autophagy as the target of mesenchymal stem cells-derived conditioned medium in rat model of myocardial ischemia/reperfusion injury.

Human amniotic membrane mesenchymal stem cells-derived conditioned medium (hAM-MSCs-CM) has positive effects against myocardial ischemia/reperfusion (MI/R) injury. However, it needs further investigations how hAM-MSCs-CM leads to the cell survival under MI/R via modulation of autophagy. The purpose of this study is investigating the effects of hAM-MSCs-CM in a rat model of MI/R injury by focusing on the role of autophagy as one of its possible mechanisms. Male Wistar rats (44 rats, 175-200g) were randomly divided into four groups: Sham, MI/R, culture media-receiving and conditioned medium-receiving. MI/R was induced by 30min of left anterior descending coronary artery ligation. After 15min reperfusion, culture media or hAM-MSCs-CM (150μl) were injected intramyocardially. At the end of the experiment, CK-MB, autophagy markers, phosphorylated and total forms of mTOR and ULK1, cardiac function and fibrosis were measured. hAM-MSCs-CM significantly decreased CK-MB levels (P < 0.0001), and also the mRNA levels of Beclin1 (P < 0.0001), LC3 (P = 0.012) and p62 (P = 0.003). In addition, hAM-MSCs-CM significantly reduced Beclin1, LC3II/LC3I and p62 protein levels (P < 0.0001), and increased p-mTOR/mTOR (P = 0.022) and p-ULK1/ULK1 (P < 0.0001) expressions. Moreover, hAM-MSCs-CM improved cardiac function and decreased fibrosis (P < 0.0001). This study showed cardioprotective effects of hAM-MSCs-CM against MI/R injury through modulation of autophagy via mTOR/ULK1 pathway. Based on these findings, it can be concluded that hAM-MSCs-CM can be offered as an attractive candidate for attenuation of MI/R injury in future, but needs further investigations.

Human amniotic membrane mesenchymal stem cells exert cardioprotective effects against isoproterenol (ISO)-induced myocardial injury through suppression of inflammation and modulation of inflammatory MAPK/NF-κB pathway.

A common cause of mortality around the world is ischemic myocardial injury. The study was conducted to examine the ability of amniotic membrane mesenchymal stem cells (AMSCs) for protection against isoproterenol (ISO)-induced myocardial injury and attempted to show the possible mechanisms by which AMSCs that can be linked to inhibition of inflammation by targeting inflammatory MAPK/NF-κB pathway. Model was established by subcutaneous injection of 170mg/kg/day of ISO for four consecutive days. Flow cytometry and echocardiography were carried out to evaluate characterization of hAMSCs and cardiac function, respectively. The expression of inflammatory cytokines was determined using ELISA assay. The activities of NF-κB and phosphorylated p38 MAPK were measured using immunohistochemical assessments. The results showed that ISO administration was resulted in cardiac dysfunction, increased levels of inflammatory cytokines that reversed by intramyocardially administration of AMSCs (P < 0. 05). Cardioprotective effects of AMSCs were associated with a significant decreased expression of NF-κB and reduced levels of phosphorylated p38 MAPK (P < 0. 05). In conclusion, our finding showed that intramyocardially administration of AMSCs could contribute to improvement of heart function and inhibition of inflammation in the site of injury by targeting inflammatory MAPK/NF-κB pathway.

Human amniotic membrane mesenchymal stem cell-conditioned medium reduces inflammatory factors and fibrosis in ovalbumin-induced asthma in mice.

What is the central question of this study? Is mesenchymal stem cell-conditioned medium capable of improving the pathological alterations of ovalbumin-induced asthma in mice? What is the main finding and its importance? Our study indicated that human amniotic membrane mesenchymal stem cell-conditioned medium is capable of modulating inflammation, fibrosis, oxidative stress and the pathological consequences of ovalbumin-induced allergic asthma in mice. Paracrine factors secreted by mesenchymal stem cells (MSCs) have immunomodulatory, anti-inflammatory and antifibrotic properties, and the conditioned medium (CM) of these cells might have functional capabilities. We examined the effects of human amniotic membrane MSC-CM (hAM-MSC-CM) on ovalbumin (OVA)-induced asthma. Forty male Balb/c mice were randomly divided into the following four groups: control; OVA (sensitized and challenged with OVA); OVA+CM (sensitized and challenged with OVA and treated with hAM-MSC-CM); and OVA+Placebo (sensitized and challenged with OVA and treated with placebo). Forty-eight hours after the last challenge, serum and bronchoalveolar lavage fluid samples were collected and used for evaluation of inflammatory factors and cells, respectively. Lung tissue sections were stained with Haematoxylin and Eosin or Masson's Trichrome to evaluate pathological changes, and oxidative stress was assessed in fresh lung tissues. Treatment with hAM-MSC-CM significantly hindered histopathological changes and fibrosis and reduced the total cell count and the percentage of eosinophils and neutrophils in bronchoalveolar lavage fluid. Furthermore, it reduced serum levels of immunoglobulinE, interleukin-4, transforming growth factor-β and lung malondialdehyde. It also increased serum levels of interferon-γ and interleukin-10, in addition to the enzymatic activity of glutathione peroxidase, catalase and superoxide dismutase in lung tissue in comparison to the OVA and OVA+Placebo groups. This study showed that administration of hAM-MSC-CM can improve pathological conditions, such as inflammation, fibrosis and oxidative stress, in OVA-induced allergic asthma.

Human amniotic membrane mesenchymal stem cells-conditioned medium attenuates myocardial ischemia-reperfusion injury in rats by targeting oxidative stress.

Objective(s):Ischemic heart diseases (IHD) are one of the major causes of death worldwide. Studies have shown that mesenchymal stem cells can secrete and release conditioned medium (CM) which has biological activities and can repair tissue injury. This study aimed to investigate the effects of human amniotic membrane mesenchymal stem cells (hAMCs)-CM on myocardial ischemia/reperfusion (I/R) injury in rats by targeting oxidative stress. Materials and Methods:Male Wistar rats (40 rats, weighing 200–250 g) were randomly divided into four groups: Sham, myocardial infarction (MI), MI + culture media, and MI + conditioned medium. MI was induced by ligation of the left anterior descending coronary artery for 30 min. After 15 min of reperfusion, intramyocardial injections of hAMCs-CM or culture media (150 μl) were performed. At the end of the experiment, serum levels of cardiac troponin-I (cTn-I), myocardial levels of malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPx), as well as cardiac histological changes were evaluated.Results:HAMCs-CM significantly decreased cTn-I and MDA levels and increased SOD and GPx activities (P<0.05). In addition, hAMCs-CM improved cardiac histological changes and decreased myocardial injury percentage (P<0.05). Conclusion:This study showed that hAMCs-CM has cardioprotective effects in the I/R injury condition. Reduction of oxidative stress by hAMCs-CM plays a significant role in this context. Based on the results of this study, it can be concluded that hAMCs-CM can be offered as a therapeutic candidate for I/R injury in the future, but more research is needed.

The Osteogenic Capacity of HumanAmniotic Membrane Mesenchymal Stem Cell (hAMSC) and Potential for Application in Maxillofacial Bone Reconstruction in Vitro Study

Amniotic membrane of human placenta is a source of abundant mesenchymal stem cell (hAMSC) which makes it a potential source of allogeneic multipotent cell for bone healing. However, much has to be explored about its isolation procedure and the osteogenic differentiation potential. The aims of this study are to establish the procurement procedure of human amniotic membrane, the isolation and culture of hAMSC, the MSC phenotypic characterization, and the in vitro osteogenic differentiation of hAMSC. Results of the study are as follows. The quality of human amniotic membrane would be best if procured from Caesarean operation under highly aseptic condition to avoid fungal and bacterial contamination on the culture. Isolation procedure using modified Soncini protocol yielded large amount of MSC with high proliferative capacity in culture medium. Characterization of hAMSC showed that the majority of the target cells exhibited specific MSC markers (CD10S and CD90) with a small number of these cells expressing CD45the marker of hematopoeitic cells. The in vitro osteogenic differentiation of hAMSC followed by Alizarin Red staining showed that osteoblastic differentiation was detected in a significantly high number of cells. This study concludes that hAMSCs isolated from human amniotic membrane have the capacity for in vitro osteogenesis which makes them be one of the potential allogeneic stem cells for application in maxillofacial bone reconstruction.

Selective Cytotoxicity of a Novel Trp-Rich Peptide against Lung Tumor Spheroids Encapsulated inside a 3D Microfluidic Device.

There is a globally rising healthcare need to develop new anticancer therapies as well as to test them on biologically relevant in vitro cancer models instead of overly simplistic 2D models. To address both these needs, a 3D lung cancer spheroid model is developed using human A549 cells trapped inside a collagen gel in a compartmentalized microfluidic device and homogenously sized (35-45 µm) multicellular tumor spheroids are obtained in 5 days. The novel tryptophan-rich peptide P1, identified earlier as a potential anticancer peptide (ACP), shows enhanced cytotoxic efficacy against A549 tumor spheroids (>75%) in clinically relevant low concentrations, while it does not affect human amniotic membrane mesenchymal stem cells at the same concentrations (<15%). The peptide also inhibits the formation of tumor spheroids by reducing cell viability as well as lowering the proliferative capacity, which is confirmed by the expression of cell proliferation marker Ki-67. The ACP offers a novel therapeutic strategy against lung cancer cells without affecting healthy cells. The microfluidic device used is likely to be useful in helping develop models for several other cancer types to test new anticancer agents.

Study of Human Amniotic Membrane Mesenchymal Stem Cells Using Gelatin and Alginate as Nontoxic Scaffolds

Perinatal mesenchymal stem cells (MSCs), for example, from amniotic membrane, have advantages over adult sources, such as bone marrow, in terms of ease of availability, cell naivety, tissue stem cell abundance, high capacity of proliferation, and less donor site morbidity, because it does not require invasive procedures. Natural polymer scaffolds, such as gelatin and alginate, are biocompatible. Combination of stem cells from amniotic membrane (hAMSCs) and gelatin or alginate as scaffold can be promising. However, cytotoxicity comparison of gelatin and alginate to hAMSCs has not been widely studied. This study was aimed to compare cytotoxicity of gelatin and alginate on hAMSCs in vitro. Isolation and culture were performed on hAMSCs of the healthy full-term pregnancy. In passage 4, Flow Cytometry CD90, CD105, and CD73 phenotype characterization was done. Colorimetric assay of 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) was performed to measure the cytotoxicity. There were three sample groups: (control group) hAMSCs with alpha-minimum essential medium (α-MEM) solution as control; (gelatin group) hAMSCs with gelatin; (alginate group) hAMSCs with alginate. Each group consisted of 12 samples. Flow cytometry of hAMSCs expressed 28.78% CD90, 36.95% CD105, and 44.41% CD73 surface markers. No sample depicted toxicity in either gelatin or alginate group, and this is indicated by the average percentage of living cells in gelatin 97.26% and in alginate 98.43%. No statistically significant difference (ρ=0.057) of cytotoxicity was found between gelatin and alginate to hAMSCs. Gelatin and alginate were nontoxic to hAMSCs in vitro.

Anti-Inflammatory and Anti-Fibrotic Effects of Human Amniotic Membrane Mesenchymal Stem Cells and Their Potential in Corneal Repair.

Acute ocular chemical burns are ophthalmic emergencies requiring immediate diagnosis and treatment as they may lead to permanent impairment of vision. The clinical manifestations of such burns are produced by exacerbated innate immune response via the infiltration of inflammatory cells and activation of stromal fibroblasts. New therapies are emerging that are dedicated to repair mechanisms that improve the ocular surface after damage; for example, transplantation of stem cells (SC) has been successfully reported for this purpose. The pursuit of easily accessible, noninvasive procedures to obtain SC has led researchers to focus on human tissues such as amniotic membrane. Human amniotic mesenchymal SC (hAM‐MSC) inhibits proinflammatory and fibrotic processes in different diseases. hAM‐MSC expresses low levels of classical MHC‐I and they do not express MHC‐II, making them suitable for regenerative medicine. The aim of this study was to evaluate the effect of intracameral injection of hAM‐MSC on the clinical manifestations, the infiltration of inflammatory cells, and the activation of stromal fibroblasts in a corneal alkali‐burn model. We also determined the in vitro effect of hAM‐MSC conditioned medium (CM) on α‐SMA+ human limbal myofibroblast (HLM) frequency and on release of neutrophil extracellular traps (NETs). Our results show that intracameral hAM‐MSC injection reduces neovascularization, opacity, stromal inflammatory cell infiltrate, and stromal α‐SMA+ cells in our model. Moreover, in in vitro assays, CM from hAM‐MSC decreased the quantity of α‐SMA+ HLM and the release of NETs. These results suggest that intracameral hAM‐MSC injection induces an anti‐inflammatory and anti‐fibrotic environment that promotes corneal wound healing. Stem Cells Translational Medicine 2018;7:906–917

The role of Schwann cells-like cells derived from human amniotic membrane mesenchymal stem cells transplantation in flap nerves regeneration

Inducing human amniotic membrane mesenchymal stem cells (hAMSCs) to Schwann cells-like cells (SCs-like cells) in vitro, and to evaluate the efficacy of transplantation of hAMSCs and SCs-like cells on nerves regeneration of the rat flaps. hAMSCs were isolated from placenta via two-step digestion and cultured by using trypsin and collagenase, then identified them by flow cytometry assay and immunofluorescence staining. The 3rd generation of hAMSCs cultured for 6 days were induced to SCs-like cells in vitro; at 19 days after induction, the levels of S-100, p75, and glial fibrillary acidic protein (GFAP) were detected by immunofluorescence staining, Western blot, and real-time fluorescence quantitative PCR (qPCR). The levels of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) were measured by ELISA in the supernatant of the 3rd generation of hAMSCs cultured for 6 days and the hAMSCs induced within 19 days. In addition, 75 female Sprague Dawley rats were taken to establish the rat denervated perforator flap model of the abdominal wall, and were divided into 3 groups ( n=25). The 3rd generation of hAMSCs (1×10 6 cells) in the proliferation period of culturing for 6 days, the SCs-like cells (1×10 6 cells), and equal volume PBS were injected subcutaneously in the skin flap of the rat in groups A, B, and C, respectively. At 2, 5, 7, 9, and 14 days after transplantation, 5 rats in each group were killed to harvest the flap frozen sections and observe the positive expression of neurofilament heavy polypeptide antibody (NF-01) by immunofluorescence staining. The cells were identified as hAMSCs by flow cytometry assay and immunofluorescence staining. The results of immunofluorescence staining, Western blot, qPCR showed that the percentage of positive cells, protein expression, and gene relative expression of S-100, p75, and GFAP in SCs-like cells group were significantly higher than those in hAMSCs group ( P<0.05). The results of ELISA demonstrated that the expression of BDNF and NGF was significantly decreased after added induced liquid 1, and the level of BDNF and NGF increased gradually with the induction of liquids 2 and 3, and the concentration of BDNF and NGF was significantly higher than that of hAMSCs group ( P<0.05). Immunofluorescence staining showed that the number of regenerated nerve fibers in group B was higher than that in groups A and C after 5-14 days of transplantation. The hAMSCs can be induced into SCs-like cells with the proper chemical factor regulation in vitro, and a large number of promoting nerve growth factor were released during the process of differentiation, and nerve regeneration in flaps being transplanted the SCs-like cells was better than that in flaps being transplanted the hAMSCs, which through a large number of BDNF and NGF were released.

Human Amniotic Membrane Mesenchymal Stem Cells inhibit Neutrophil Extracellular Traps through TSG-6

The mesenchymal stem cells obtained from human amniotic membrane (hAMSC) possess immunosuppressive functions through soluble factors such as prostanoids and proteins; thus, they have been proposed to ameliorate inflammatory processes. On the other hand, activated neutrophils are cells of the first line of immune defense that are able to release extracellular traps (NETs). NETs are formed of DNA and granular components; however, the excessive release of NETs is associated with the development of autoimmune and chronic inflammatory diseases. In this study, we identified that conditioned medium (CM) from hAMSC was able to diminish NETs release, as well as the production of reactive oxygen species (ROS) and the mitochondrial membrane potential from LPS-stimulated mouse bone marrow-derived neutrophils (BMN). Interestingly, NETs inhibition, ROS levels decrease and mitochondrial membrane potential loss were reverted when LPS-stimulated murine derived BMN were exposed to the CM from hAMSC transfected with TSG-6-siRNA. Finally, rhTSG6 was able to significantly diminish NETs release in BMN. These data suggest an inhibition mechanism of NETs ROS-dependent in which TSG-6 participates. Consequently, we propose the hAMSC use as a therapeutic candidate in the treatment of inflammatory diseases in which NETs are involved.

Transplantation of Human Amniotic Mesenchymal Stem Cells Promotes Functional Recovery in a Rat Model of Traumatic Spinal Cord Injury.

Human amniotic membrane mesenchymal stem cells (hAMSCs) are considered ideal candidate stem cells for cell-based therapy. In this study, we assessed whether hAMSCs transplantation promotes neurological functional recovery in rats after traumatic spinal cord injury (SCI). In addition, the potential mechanisms underlying the possible benefits of this therapy were investigated. Female Sprague-Dawley rats were subjected to SCI using a weight drop device and then hAMSCs, or phosphate-buffered saline (PBS) were immediately injected into the contused dorsal spinal cord at 2mm rostral and 2mm caudal to the injury site. Our results indicated that transplanted hAMSCs migrated in the host spinal cord without differentiating into neuronal or glial cells. Compared with the control group, hAMSCs transplantation significantly decreased the numbers of ED1+ macrophages/microglia and caspase-3+ cells. In addition, hAMSCs transplantation significantly increased the levels of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) in the injured spinal cord, and promoted both angiogenesis and axonal regeneration. These effects were associated with significantly improved neurobehavioral recovery in the hAMSCs transplantation group. These results show that transplantation of hAMSCs provides neuroprotective effects in rats after SCI, and could be candidate stem cells for the treatment of SCI.

Transplantation of human amniotic mesenchymal stem cells promotes neurological recovery in an intracerebral hemorrhage rat model

Human amniotic membrane mesenchymal stem cells (hAMSCs) have recently been suggested as ideal candidate stem cells for cell-based therapy. Many studies have reported the therapeutic effects of hAMSCs in numerous disease models. However, no studies have used hAMSCs to treat intracerebral hemorrhage (ICH). In the present study, we examined the therapeutic potential of hAMSCs in a rat model of ICH, and characterized the possible mechanisms of action. Adult male Wistar rats were subjected to ICH by intrastriatal injection of VII collagenase, and then were intracerebrally administered hAMSCs, fibroblasts, or phosphate-buffered saline (PBS) at 24 h after ICH. Compared with the fibroblasts and the PBS control, hAMSCs treatment significantly promoted neurological recovery, and reduced the numbers of ED1+ activated microglia, as well as myeloperoxidase (MPO+), and caspase-3+ cells in the brain injury model. In addition, hAMSCs treatment significantly increased the expression of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) in the injured brain, and promoted neurogenesis and angiogenesis, compared with the fibroblasts and the PBS control. The transplanted hAMSCs survived for at least 27 days and were negative for β-tubulin III and glial fibrillary acidic protein (GFAP). Taken together, the results suggest that hAMSCs treatment significantly promotes neurological recovery in rats after ICH. The mechanism of action could be mediated by inhibition of inflammation and apoptosis, increasing neurotrophic factor expression, and promotion of neurogenesis and angiogenesis. Thus, hAMSCs are candidate stem cells for the treatment of ICH.