Human amniotic fluid stem cell differentiation along smooth muscle lineage

An Engineered Living Intestinal Muscle Patch Produces Macroscopic Contractions that can Mix and Break Down Artificial Intestinal Contents

The intestinal muscle layers execute various gut wall movements to achieve controlled propulsion and mixing of intestinal content. Engineering intestinal muscle layers with complex contractile function is critical for developing bioartificial intestinal tissue to treat patients with short bowel syndrome. Here, the first demonstration of a living intestinal muscle patch capable of generating three distinct motility patterns and displaying multiple digesta manipulations is reported. Assessment of contractility, cellular morphology, and transcriptome profile reveals that successful generation of the contracting muscle patch relies on both biological factors in a serum-free medium and environmental cues from an elastic electrospun gelatin scaffold. By comparing gene-expression patterns among samples, it is shown that biological factors from the medium strongly affect ion-transport activities, while the scaffold unexpectedly regulates cell-cell communication. Analysis of ligandreceptor interactome identifies scaffold-driven changes in intercellular communication, and 78% of the upregulated ligand-receptor interactions are involved in the development and function of enteric neurons. The discoveries highlight the importance of combining biomolecular and biomaterial approaches for tissue engineering. The living intestinal muscle patch represents a pivotal advancement for building functional replacement intestinal tissue. It offers a more physiological model for studying GI motility and for preclinical drug discovery.

Building gut from scratch - progress and update of intestinal tissue engineering

Short bowel syndrome (SBS), a condition defined by insufficient absorptive intestinal epithelium, is a rare disease, with an estimated prevalence up to 0.4 in 10,000 people. However, it has substantial morbidity and mortality for affected patients. The mainstay of treatment in SBS is supportive, in the form of intravenous parenteral nutrition, with the aim of achieving intestinal autonomy. The lack of a definitive curative therapy has led to attempts to harness innate developmental and regenerative mechanisms to engineer neo-intestine as an alternative approach to addressing this unmet clinical need. Exciting advances have been made in the field of intestinal tissue engineering (ITE) over the past decade, making a review in this field timely. In this Review, we discuss the latest advances in the components required to engineer intestinal grafts and summarize the progress of ITE. We also explore some key factors to consider and challenges to overcome when transitioning tissue-engineered intestine towards clinical translation, and provide the future outlook of ITE in therapeutic applications and beyond.

Regenerative medicine for childhood gastrointestinal diseases

Several paediatric gastrointestinal diseases result in life-shortening organ failure. For many of these conditions, current therapeutic options are suboptimal and may not offer a cure. Regenerative medicine is an inter-disciplinary field involving biologists, engineers, and clinicians that aims to produce cell and tissue-based therapies to overcome organ failure. Exciting advances in stem cell biology, materials science, and bioengineering bring engineered gastrointestinal cell and tissue therapies to the verge of clinical trial. In this review, we summarise the requirements for bioengineered therapies, the possible sources of the various cellular and non-cellular components, and the progress towards clinical translation of oesophageal and intestinal tissue engineering to date.

Human Dental Pulp-Derived Mesenchymal Stem Cell Potential to Differentiate into Smooth Muscle-Like Cells In Vitro

Previous studies have shown that mesenchymal stem cells (MSCs) derived from various tissue sources can be differentiated into smooth muscle-like cells (SMLCs) in vitro. In this paper, dental pulp-derived mesenchymal stem cells (DPSCs) were evaluated for their differentiation ability towards smooth muscle-like cells (SMLCs) under the effect of widely used cytokines (TGF-β1 and PDGF-BB) with special focus on different culturing environments. For this purpose, both the commercially used culturing plates (Norm-c) and 0.1% gelatin-precoated (Gel-c) plates were used. Isolated cells displayed plastic adherence, pluripotency and cell surface marker profiling, and adipogenic and osteogenic differentiation potential with lineage specific marker expression. Differentiated cells induced under different culturing plates showed successful differentiation into SMLCs by positively expressing smooth muscle cell (SMC) specific markers both at the mRNA and protein levels. Gelatin coating could substantially enhance DPSC differentiation potential than Norm-c-induced cells. However, the absence of mature marker MHY-11 by immunostaining results from all treatment groups further indicated the development of immature and synthetic SMLCs. Finally, it was concluded that DPSC differentiation ability into SMLCs can be enhanced under cytokine treatment as well as by altering the cellular niche by precoating the culturing plates with suitable substrates. However, to get fully functional, contractile, and mature SMLCs, still many different cytokine cocktail combinations and more suitable coating substrates will be needed.

Differentiation potential of different regions-derived same donor human Wharton's jelly mesenchymal stem cells into functional smooth muscle-like cells

The present study evaluates the transdifferentiation potential of different region-derived same donor Wharton's jelly MSCs (WJMSCs) into functional smooth muscle-like cells (SMLCs). All regions showed baseline expression for early smooth muscle cell (SMC) markers (αSMA and SM22-α) whereas mid marker CALPONIN gradually reduced during in vitro culture expansion and late marker myosin heavy chain type-11 (MHY-11) was completely absent. Furthermore, WJMSCs were induced to SMLCs using DMEM containing 10% FBS supplemented with different concentrations/combinations of TGF-β1 and PDGF-BB under normoxia (20% O₂) condition. Three treatment groups namely group A: 2.5 ng/ml TGF-β1, group B: 5 ng/ml PDGF-BB and group C: 2.5 ng/ml TGF-β1 + 5 ng/ml PDGF-BB were used for the induction of WJMSCs into SMLCs. Cells were evaluated for SMC-specific marker expression at different time intervals. Finally, selection of the SMC-specific highly potent region along with the most suitable treatment group was done on the basis of highest outcome in terms of SMC-specific marker expression and functional competence of transdifferentiated cells. Among all regions, baby region-derived WJMSCs (B-WJMSCs) exhibited highest SMC marker expression and functional ability. To mimic the in vivo physiological conditions, hypoxic conditions (3% O₂) were used to evaluate the effect of low oxygen on the SMLC differentiation potential of selected WJMSCs using previously used same parameters. Annexin-V assay was performed to check the effect of cytokines and different oxygen concentrations, which revealed no significant differences. It was concluded that different induction conditions have different but positive effects on the functional SMLC differentiation ability of WJMSCs.

Prenatal transplantation of human amniotic fluid stem cells for spinal muscular atrophy

PURPOSE OF REVIEW

To review the current medical and stem-cell therapy for spinal muscular atrophy (SMA) and prenatal transplantation of amniotic fluid stem cells in the future.

RECENT FINDINGS

SMA is an autosomal recessive inheritance of neurodegenerative disease, which is caused of the mutation in survival motor neuron. The severe-type SMA patients usually die from the respiratory failure within 2 years after birth. Recently, researchers had found that 3-methyladenine could inhibit the autophagy and had the capacity to reduce death of the neurons. The first food and drug administration-approved drug to treat SMA, Nusinersen, is a modified antisense oligonucleotide to target intronic splicing silencer N1 just recently launched. Not only medical therapy, but also stem cells including neural stem cells, embryonic stem cells, mesenchymal stem cells, and induced pluripotent stem cells could show the potential to repair the injured tissue and differentiate into neuron cells to rescue the SMA animal models. Human amniotic fluid stem cells (HAFSCs) share the potential of mesenchymal stem cells and could differentiate into tri-lineage-relative cells, which are also having the ability to restore the injured neuro-muscular function. In this review, we further demonstrate the therapeutic effect of using HAFSCs to treat type III SMA prenatally. HAFSCs, similar to other stem cells, could also help the improvement of SMA with even longer survival.

SUMMARY

The concept of prenatal stem-cell therapy preserves the time window to treat disease in utero with much less cell number. Stem cell alone might not be enough to correct or cure the SMA but could be applied as the additional therapy combined with antisense oligonucleotide in the future.

Prenatal diagnosis of sex chromosome mosaicism with two marker chromosomes in three cell lines and a review of the literature

The present study described the diagnosis of a fetus with sex chromosome mosaicism in three cell lines and two marker chromosomes. A 24‑year‑old woman underwent amniocentesis at 21 weeks and 4 days of gestation due to noninvasive prenatal testing identifying that the fetus had sex chromosome abnormalities. Amniotic cell culture revealed a karyotype of 45,X[13]/46,X,+mar1[6]/46,X,+mar2[9], and prenatal ultrasound was unremarkable. The woman underwent repeat amniocentesis at 23 weeks and 4 days of gestation for molecular detection. Single nucleotide polymorphism (SNP) microarray analysis on uncultured amniocytes revealed that the fetus had two Y chromosomes and 7.8‑Mb deletions in Yq11.222q12. The deletion regions included DAZ, RBMY and PRY genes, which could cause spermatogenesis obstacle and sterility. Interphase fluorescence in situ hybridization (FISH) using centromeric probes DXZ1/DYZ3/D18Z1 was performed on uncultured amniocytes to verify the two marker chromosomes to be Y chromosome derivatives. According to these examinations, the mar1 was identified as a derivative of the Y chromosome with a deletion in Yq11.222q12, and the mar2 was identified as a dicentric derivative of the Y chromosome. The molecular karyotype was therefore 45,X,ish(DXZ1+, DYZ3‑,D18Z1++)[5]/46,X,del(Y)(q11.222),ish(DXZ1+,DYZ3+,D18Z1++)[11]/46, X,idic(Y)(q11.222),ish(DXZ1+,DYZ3++,D18Z1++)[14]. The comprehensive use of cytogenetic, SNP array and FISH detections was advantageous for accurately identifying the karyotype, identifying the origin of the marker chromosome and preparing effective genetic counseling.

Glycoprotein M6B Interacts with TβRI to Activate TGF-β-Smad2/3 Signaling and Promote Smooth Muscle Cell Differentiation

Smooth muscle cells (SMCs), which form the walls of blood vessels, play an important role in vascular development and the pathogenic process of vascular remodeling. However, the molecular mechanisms governing SMC differentiation remain poorly understood. Glycoprotein M6B (GPM6B) is a four-transmembrane protein that belongs to the proteolipid protein family and is widely expressed in neurons, oligodendrocytes, and astrocytes. Previous studies have revealed that GPM6B plays a role in neuronal differentiation, myelination, and osteoblast differentiation. In the present study, we found that the GPM6B gene and protein expression levels were significantly upregulated during transforming growth factor-β1 (TGF-β1)-induced SMC differentiation. The knockdown of GPM6B resulted in the downregulation of SMC-specific marker expression and repressed the activation of Smad2/3 signaling. Moreover, GPM6B regulates SMC Differentiation by Controlling TGF-β-Smad2/3 Signaling. Furthermore, we demonstrated that similar to p-Smad2/3, GPM6B was profoundly expressed and coexpressed with SMC differentiation markers in embryonic SMCs. Moreover, GPM6B can regulate the tightness between TβRI, TβRII, or Smad2/3 by directly binding to TβRI to activate Smad2/3 signaling during SMC differentiation, and activation of TGF-β-Smad2/3 signaling also facilitate the expression of GPM6B. Taken together, these findings demonstrate that GPM6B plays a crucial role in SMC differentiation and regulates SMC differentiation through the activation of TGF-β-Smad2/3 signaling via direct interactions with TβRI. This finding indicates that GPM6B is a potential target for deriving SMCs from stem cells in cardiovascular regenerative medicine. Stem Cells 2018 Stem Cells 2019;37:190-201.

Smooth muscle cell differentiation from rabbit amniotic cells

Amniotic fluid (AF) is the liquid layer that provides mechanical support and allows movement of the fetus during embryogenesis. Mesenchymal stem cells (MSCs), which have differentiation capacity, are also found in AF-derived cells at a low ratio. Smooth muscle cells (SMCs) play an important role in organ function and are frequently used in tissue engineering. We examined the differentiation of AF-derived MSCs (AMSCs) into SMCs. AMSCs were sorted from cultured amniotic cells and differentiated into SMCs using differentiation agents, including platelet-derived growth factor BB (PDGF-BB) and tumor growth factor β (TGF-β). Characterization of differentiated SMCs was confirmed morphologically, molecularly (via quantitative polymerase chain reaction [qPCR] and immunocytochemistry [ICC]), and functionally (using a contractile assay and fluo-4 calcium signaling assay). Poly(lactide-co-glycolide) (PLGA) scaffolds were fabricated, and the attachment capacity of AMSCs was assessed via scanning electron microscopy. AMSCs were successfully differentiated into SMCs. Our results indicate that AMSCs change their morphology and exhibit increased expression of ACTA2 and MYH11, which was confirmed via qPCR and ICC. Furthermore, functional experiments revealed that differentiated SMCs had both contraction ability and increased Ca² concentration in the cytoplasm. Finally, PLGA scaffolds were prepared and AMSCs were successfully planted onto the scaffolds. The AMSCs fully differentiated into functional SMCs, and the PLGA polymer is a suitable scaffold material for AMSCs. With further clinical trials, AF-derived MSC-based SMC engineering may become a highly efficient treatment option.

Multi-stage bioengineering of a layered oesophagus with in vitro expanded muscle and epithelial adult progenitors

A tissue engineered oesophagus could overcome limitations associated with oesophageal substitution. Combining decellularized scaffolds with patient-derived cells shows promise for regeneration of tissue defects. In this proof-of-principle study, a two-stage approach for generation of a bio-artificial oesophageal graft addresses some major challenges in organ engineering, namely: (i) development of multi-strata tubular structures, (ii) appropriate re-population/maturation of constructs before transplantation, (iii) cryopreservation of bio-engineered organs and (iv) in vivo pre-vascularization. The graft comprises decellularized rat oesophagus homogeneously re-populated with mesoangioblasts and fibroblasts for the muscle layer. The oesophageal muscle reaches organised maturation after dynamic culture in a bioreactor and functional integration with neural crest stem cells. Grafts are pre-vascularised in vivo in the omentum prior to mucosa reconstitution with expanded epithelial progenitors. Overall, our optimised two-stage approach produces a fully re-populated, structurally organized and pre-vascularized oesophageal substitute, which could become an alternative to current oesophageal substitutes.

Combining decellularised scaffolds with patient-derived cells holds promise for bioengineering of functional tissues. Here the authors develop a two-stage approach to engineer an oesophageal graft that retains the structural organisation of native oesophagus.

Emerging Strategies for Stem Cell Lineage Commitment in Tissue Engineering and Regenerative Medicine

Stem cells have transformed the fields of tissue engineering and regenerative medicine, and their potential to further advance these fields cannot be overstated. The stem cell niche is a dynamic microenvironment that determines cell fate during development and tissue repair following an injury. Classically, stem cells were studied in isolation of their microenvironment; however, contemporary research has produced a myriad of evidence that shows the importance of multiple aspects of the stem cell niche in regulating their processes. In the context of tissue engineering and regenerative medicine studies, the niche is an artificial environment provided by culture conditions. In vitro culture conditions may involve coculturing with other cell types, developing specific biomaterials, and applying relevant forces to promote the desired lineage commitment. Considerable advance has been made over the past few years toward directed stem cell differentiation; however, the unspecific differentiation of stem cells yielding a mixed population of cells has been a challenge. In this review, we provide a systematic review of the emerging strategies used for lineage commitment within the context of tissue engineering and regenerative medicine. These strategies include scaffold pore-size and pore-shape gradients, stress relaxation, sonic and electromagnetic effects, and magnetic forces. Finally, we provide insights and perspectives into future directions focusing on signaling pathways activated during lineage commitment using external stimuli.

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

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

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

Background

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

Material/Methods

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

Results

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

Conclusions

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

Exogenous transforming growth factor-β1 enhances smooth muscle differentiation in embryonic mouse jejunal explants

An ex vivo experimental strategy that replicates in vivo intestinal development would in theory provide an accessible setting with which to study normal and dysmorphic gut biology. The current authors recently described a system in which mouse embryonic jejunal segments were explanted onto semipermeable platforms and fed with chemically defined serum-free media. Over 3 days in organ culture, explants formed villi and they began to undergo spontaneous peristalsis. As defined in the current study, the wall of the explanted gut failed to form a robust longitudinal smooth muscle (SM) layer as it would do in vivo over the same time period. Given the role of transforming growth factor β1 (TGFβ1) in SM differentiation in other organs, it was hypothesized that exogenous TGFβ1 would enhance SM differentiation in these explants. In vivo, TGFβ receptors I and II were both detected in embryonic longitudinal jejunal SM cells and, in organ culture, exogenous TGFβ1 induced robust differentiation of longitudinal SM. Microarray profiling showed that TGFβ1 increased SM specific transcripts in a dose dependent manner. TGFβ1 proteins were detected in amniotic fluid at a time when the intestine was physiologically herniated. By analogy with the requirement for exogenous TGFβ1 for SM differentiation in organ culture, the TGFβ1 protein that was demonstrated to be present in the amniotic fluid may enhance intestinal development when it is physiologically herniated in early gestation. Future studies of embryonic intestinal cultures should include TGFβ1 in the defined media to produce a more faithful model of in vivo muscle differentiation. Copyright © 2017 The Authors Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons, Ltd.

Comparative analysis of human Wharton's jelly mesenchymal stem cells derived from different parts of the same umbilical cord

Easy isolation, lack of ethical issues, high proliferation, multi-lineage differentiation potential and immunomodulatory properties of umbilical cord (UC)-derived mesenchymal stem cells (MSCs) make them a valuable tool in stem cell research. Recently, Wharton’s jelly (WJ) was proven as the best MSC source among various compartments of UC. However, it is still unclear whether or not Wharton’s jelly-derived MSCs (WJMSCs) from different parts of the whole cord exhibit the same characteristics. There may be varied MSCs present in different parts of WJ throughout the length of the UC. For this purpose, using an explant attachment method, WJMSCs were isolated from three different parts of the UC, mainly present towards the placenta (mother part), the center of the whole cord (central part) and the part attached to the fetus (baby part). WJMSCs from all three parts were maintained in normal growth conditions (10% ADMEM) and analyzed for mesenchymal markers, pluripotent genes, proliferation rate and tri-lineage differentiation potential. All WJMSCs were highly proliferative, positively expressed CD90, CD105, CD73 and vimentin, while not expressing CD34, CD45, CD14, CD19 or HLA-DR, differentiated into adipocytes, osteocytes and chondrocytes and expressed pluripotency markers OCT-4, SOX-2 and NANOG at gene and protein levels. Furthermore, MSCs derived from all the parts were shown to have potency towards hepatocyte-like cell differentiation. Human bone marrow-derived MSCs were used as a positive control. Finally, we conclude that WJMSCs derived from all the parts are valuable sources and can be efficiently used in various fields of regenerative medicine.

Isolation of myogenic progenitor cell population from human placenta: A pilot study

PURPOSE

The purpose of this study was to demonstrate a method of isolating myogenic progenitor cells from human placenta chorionic villi and to confirm the myogenic characteristics of the isolated cells.

METHODS

Cells were isolated from chorionic villi of a second trimester male placenta via a combined enzymatic digestion and explant culture. A morphologically distinct subpopulation of elongated and multinucleated cells was identified. This subpopulation was manually passaged from the explant culture, expanded, and analyzed by fluorescence in situ hybridization (FISH) assay, immunocytochemistry, and flow cytometry. Myogenic characteristics including alignment and fusion were tested by growing these cells on aligned polylactic acid microfibrous scaffold in a fusion media composed of 2% horse serum in Dulbecco's modified Eagle medium/high glucose.

RESULTS

The expanded subpopulation was uniformly positive for integrin α-7. Presence of Y-chromosome by FISH analysis confirmed chorionic villus origin rather than maternal cell contamination. Isolated cells grew, aligned, and fused on the microfibrous scaffold, and they expressed myogenin, desmin, and MHC confirming their myogenic identity.

CONCLUSION

Myogenic progenitor cells can be isolated from human chorionic villi. This opens the possibility for translational and clinical applications using autologous myogenic cells for possible engraftment in treatment of chest and abdominal wall defects.

The amniotic fluid as a source of mesenchymal stem cells with lung-specific characteristics

The amniotic fluid is a clinically accessible source of mesenchymal stem cells (AF-MSC) during gestation, which enables autologous cellular therapy for perinatal disorders. The origin of AF-MSC remains elusive: renal and neuronal progenitors have been isolated from the AF-MSC pool, yet no cells with pulmonary characteristics. We analyzed gene expression of pulmonary and renal markers of 212 clonal lines of AF-MSC isolated from amniocentesis samples. AF-MSC were cultured on dishes coated with extracellular matrix (ECM) proteins from decellularized fetal rabbit lungs. In vivo differentiation potential of AF-MSC that expressed markers suggestive of lung fate was tested by renal subcapsular injections in immunodeficient mice. Of all the isolated AF-MSC lines, 26% were positive for lung endodermal markers FOXA2 and NKX2.1 and lacked expression of renal markers (KSP). This AF-MSC subpopulation expressed other lung-specific factors, including IRX1, P63, FOXP2, LGR6, SFTC, and PDPN. Pulmonary marker expression decreased over passages when AF-MSC were cultured under conventional conditions, yet remained more stable when culturing the cells on lung ECM-coated dishes. Renal subcapsular injection of AF-MSC expressing lung-specific markers resulted in engrafted cells that were SPTB positive. These data suggest that FOXA2+/NKX2.1+/KSP- AF-MSC lines have lung characteristics which are supported by culture on lung ECM-coated dishes.

In vitro differentiation of endometrial regenerative cells into smooth muscle cells: Α potential approach for the management of pelvic organ prolapse

Pelvic organ prolapse (POP), is a common condition in parous women. Synthetic mesh was once considered to be the standard of care; however, the use of synthetic mesh is limited by severe complications, thus creating a need for novel approaches. The application of cell-based therapy with stem cells may be an ideal alternative, and specifically for vaginal prolapse. Abnormalities in vaginal smooth muscle (SM) play a role in the pathogenesis of POP, indicating that smooth muscle cells (SMCs) may be a potential therapeutic target. Endometrial regenerative cells (ERCs) are an easily accessible, readily available source of adult stem cells. In the present study, ERCs were obtained from human menstrual blood, and phase contrast microscopy and flow cytometry were performed to characterize the morphology and phenotype of the ERCs. SMC differentiation was induced by a transforming growth factor β1-based medium, and the induction conditions were optimized. We defined the SMC characteristics of the induced cells with regard to morphology and marker expression using transmission electron microscopy, western blot analysis, immunocytofluorescence and RT-PCR. Examining the expression of the components of the Smad pathway and phosphorylated Smad2 and Smad3 by western blot analysis, RT-PCR and quantitative PCR demonstrated that the 'TGFBR2/ALK5/Smad2 and Smad3' pathway is involved, and both Smad2 and Smad3 participated in SMC differentiation. Taken together, these findings indicate that ERCs may be a promising cell source for cellular therapy aimed at modulating SM function in the vagina wall and pelvic floor in order to treat POP.

Mouse white adipose tissue-derived mesenchymal stem cells gain pericentral and periportal hepatocyte features after differentiation in vitro, which are preserved in vivo after hepatic transplantation

AIM

Mesenchymal stem cells may differentiate into hepatocyte-like cells in vitro and in vivo. Therefore, they are considered a novel cell resource for the treatment of various liver diseases. Here, the aim was to demonstrate that mesenchymal stem cells may adopt both perivenous and periportal hepatocyte-specific functions in vitro and in vivo.

METHODS

Adipose tissue-derived mesenchymal stem cells were isolated from immunodeficient C57BL/6 (B6.129S6-Rag2(tm1Fwa) Prf1(tm1Clrk) ) mice and differentiated into the hepatocytic phenotype by applying a simple protocol. Their physiological and metabolic functions were analysed in vitro and after hepatic transplantation in vivo.

RESULTS

Mesenchymal stem cells changed their morphology from a fibroblastoid into shapes of osteocytes, chondrocytes, adipocytes and hepatocytes. Typical for mesenchymal stem cells, hematopoietic marker genes were not expressed. CD90, which is not expressed on mature hepatocytes, decreased significantly after hepatocytic differentiation. Markers indicative for liver development like hepatic nuclear factor 4 alpha, or for perivenous hepatocyte specification like cytochrome P450 subtype 3a11, and CD26 were significantly elevated. Periportal hepatocyte-specific markers like carbamoylphosphate synthetase 1, the entry enzyme of the urea cycle, were up-regulated. Consequently, cytochrome P450 enzyme activity and urea synthesis increased significantly to values comparable to cultured primary hepatocytes. Both perivenous and periportal qualities were preserved after hepatic transplantation and integration into the host parenchyma.

CONCLUSIONS

Adult mesenchymal stem cells from adipose tissue differentiated into hepatocyte-like cells featuring both periportal and perivenous functions. Hence, they are promising candidates for the treatment of region-specific liver cell damage and may support organ regeneration in acute and chronic liver diseases.

Mechanisms of human amniotic epithelial cell transplantation in treating stage III pressure ulcer in a rat model

The aim of the present study was to determine the function of human amniotic epithelial cell transplantation (hAECT) in promoting the healing of rats with stage III pressure ulcer (PU) and to initially investigate its possible mechanisms. A total of 96 Sprague Dawley rats were allocated at random into the model, hAECT, conventional treatment or control groups (n=24 per group). In each group, 6 rats were observed to determine the wound-healing rate. The mRNA and protein expression levels of vascular endothelial growth factor (VEGF) and tumor necrosis factor (TNF)-α in the wound tissue and serum were detected using reverse transcription-quantitative polymerase chain reaction analysis and enzyme-linked immunosorbent assay. The transplantation of hAECs significantly increased the healing rate of the stage III PUs and was accompanied by the significant upregulation of VEGF mRNA and protein expression levels and the significant downregulation of TNF-α mRNA and protein expression. Immunofluorescence staining showed that, on day 7 of transplantation, hAECs remained alive inside the skin tissues. Therefore, hAECT through subcutaneous injection appears to significantly improve the wound-healing rate of stage III PUs in rats, and this effect may be associated with the upregulation of the proangiogenic factor VEGF and the downregulation of the inflammatory cytokine TNF-α.

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

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

Tissue-engineered vascular grafts created from human induced pluripotent stem cells

The utility of human induced pluripotent stem cells (hiPSCs) to create tissue-engineered vascular grafts was evaluated in this study. hiPSC lines were first induced into a mesenchymal lineage via a neural crest intermediate using a serum-free, chemically defined differentiation scheme. Derived cells exhibited commonly known mesenchymal markers (CD90, CD105, and CD73 and negative marker CD45) and were shown to differentiate into several mesenchymal lineages (osteogenic, chondrogenic, and adipogenic). Functional vascular grafts were then engineered by culturing hiPSC-derived mesenchymal progenitor cells in a pulsatile bioreactor system over 8 weeks to induce smooth muscle cell differentiation and collagenous matrix generation. Histological analyses confirmed layers of calponin-positive smooth muscle cells in a collagen-rich matrix. Mechanical tests revealed that grafts had an average burst pressure of 700 mmHg, which is approximately half that of native veins. Additionally, studies revealed that karyotypically normal mesenchymal stem cell clones led to generation of grafts with predicted features of engineered vascular grafts, whereas derived clones having chromosomal abnormalities generated calcified vessel constructs, possibly because of cell apoptosis during culture. Overall, these results provide significant insight into the utility of hiPS cells for vascular graft generation. They pave the way for creating personalized, patient-specific vascular grafts for surgical applications, as well as for creating experimental models of vascular development and disease.

Serum-free spheroid suspension culture maintains mesenchymal stem cell proliferation and differentiation potential

There have been many clinical trials recently using ex vivo-expanded human mesenchymal stem cells (MSCs) to treat several disease states such as graft-versus-host disease, acute myocardial infarction, Crohn's disease, and multiple sclerosis. The use of MSCs for therapy is expected to become more prevalent as clinical progress is demonstrated. However, the conventional 2-dimensional (2D) culture of MSCs is laborious and limited in scale potential. The large dosage requirement for many of the MSC-based indications further exacerbates this manufacturing challenge. In contrast, expanding MSCs as spheroids does not require a cell attachment surface and is amenable to large-scale suspension cell culture techniques, such as stirred-tank bioreactors. In the present study, we developed and optimized serum-free media for culturing MSC spheroids. We used Design of Experiment (DoE)-based strategies to systematically evaluate media mixtures and a panel of different components for effects on cell proliferation. The optimization yielded two prototype serum-free media that enabled MSCs to form aggregates and proliferate in both static and dynamic cultures. MSCs from spheroid cultures exhibited the expected immunophenotype (CD73, CD90, and CD105) and demonstrated similar or enhanced differentiation potential toward all three lineages (osteogenic, chondrogenic, adipogenic) as compared with serum-containing adherent MSC cultures. Our results suggest that serum-free media for MSC spheroids may pave the way for scale-up production of MSCs in clinically relevant manufacturing platforms such as stirred tank bioreactors.

Tissue engineering of urinary bladder and urethra: advances from bench to patients

Urinary tract is subjected to many varieties of pathologies since birth including congenital anomalies, trauma, inflammatory lesions, and malignancy. These diseases necessitate the replacement of involved organs and tissues. Shortage of organ donation, problems of immunosuppression, and complications associated with the use of nonnative tissues have urged clinicians and scientists to investigate new therapies, namely, tissue engineering. Tissue engineering follows principles of cell transplantation, materials science, and engineering. Epithelial and muscle cells can be harvested and used for reconstruction of the engineered grafts. These cells must be delivered in a well-organized and differentiated condition because water-seal epithelium and well-oriented muscle layer are needed for proper function of the substitute tissues. Synthetic or natural scaffolds have been used for engineering lower urinary tract. Harnessing autologous cells to produce their own matrix and form scaffolds is a new strategy for engineering bladder and urethra. This self-assembly technique avoids the biosafety and immunological reactions related to the use of biodegradable scaffolds. Autologous equivalents have already been produced for pigs (bladder) and human (urethra and bladder). The purpose of this paper is to present a review for the existing methods of engineering bladder and urethra and to point toward perspectives for their replacement.