Bilayer Amniotic Membrane/Nano-fibrous Fibroin Scaffold Promotes Differentiation Capability of Menstrual Blood Stem Cells into Keratinocyte-Like Cells

Amniotic membrane in wound healing: new perspectives

There are several reasons for skin damage, including genetic factors, disorders, acute trauma, hard-to-heal wounds, or surgical interventions. Whatever the cause, wounds have a substantial impact on people who experience them, their caregivers and the healthcare system. Advanced wound care products have been researched and developed, providing an opportunity for faster and more complete healing. Tissue engineering (TE) is a promising strategy that can overcome limitations when choosing a graft for a wound. Amniotic membrane is a highly abundant, readily available, and inexpensive biological tissue that does not raise ethical concerns, with many applications in different fields of TE and regenerative medicine. It has attractive physical characteristics, such as elasticity, rigidity and mechanical strength, among others. The effects can also be potentiated by association with other substances, such as hyaluronic acid and growth factors. This paper describes new perspectives involving the use of amniotic membranes.

Development of a Composite Hydrogel Containing Statistically Optimized PDGF-Loaded Polymeric Nanospheres for Skin Regeneration: In Vitro Evaluation and Stem Cell Differentiation Studies

Platelet-derived growth factor-BB (PDGF-BB) is a polypeptide growth factor generated by platelet granules faced to cytokines. It plays a role in forming and remodeling various tissue types, including epithelial tissue, through interaction with cell-surface receptors on most mesenchymal origin cells. However, it breaks down quickly in biological fluids, emphasizing the importance of preserving them from biodegradation. To address this challenge, we formulated and evaluated PDGF-encapsulated nanospheres (PD@PCEC) using polycaprolactone-polyethylene glycol-polycaprolactone. PD@PCECs were fabricated through the triple emulsion methodology and optimized by using the Box-Behnken design. The encapsulation efficiency (EE) of nanoencapsulated PDGF-BB was investigated concerning four variables: stirring rate (X1), stirring duration (X2), poly(vinyl alcohol) concentration (X3), and PDGF-BB concentration (X4). The selected optimized nanospheres were integrated into a gelatin-collagen scaffold (PD@PCEC@GC) and assessed for morphology, biocompatibility, in vitro release, and differentiation-inducing activity in human adipose-derived stem cells (hADSCs). The optimized PD@PCEC nanospheres exhibited a particle size of 177.9 ± 91 nm, a zeta potential of 5.2 mV, and an EE of 87.7 ± 0.44%. The release profile demonstrated approximately 85% of loaded PDGF-BB released during the first 360 h, with a sustained release over the entire 504 h period, maintaining bioactivity of 87.3%. The study also included an evaluation of the physicochemical properties of the scaffolds and an assessment of hADSC adhesion to the scaffold's surface. Additionally, hADSCs cultivated within the scaffold effectively differentiated into keratinocyte-like cells (KLCs) over 21 days, evidenced by morphological changes and upregulation of keratinocyte-specific genes, including cytokeratin 18, cytokeratin 19, and involucrin, at both transcriptional and protein levels.

A Systematic Review of Stem Cell Differentiation into Keratinocytes for Regenerative Applications

To improve wound healing or treatment of other skin diseases, and provide model cells for skin biology studies, in vitro differentiation of stem cells into keratinocyte-like cells (KLCs) is very desirable in regenerative medicine. This study examined the most recent advancements in in vitro differentiation of stem cells into KLCs, the effect of biofactors, procedures, and preparation for upcoming clinical cases. A range of stem cells with different origins could be differentiated into KLCs under appropriate conditions. The most effective ways of stem cell differentiation into keratinocytes were found to include the co-culture with primary epithelial cells and keratinocytes, and a cocktail of growth factors, cytokines, and small molecules. KLCs should also be supported by biomaterials for the extracellular matrix (ECM), which replicate the composition and functionality of the in vivo extracellular matrix (ECM) and, thus, support their phenotypic and functional characteristics. The detailed efficient characterization of different factors, and their combinations, could make it possible to find the significant inducers for stem cell differentiation into epidermal lineage. Moreover, it allows the development of chemically known media for directing multi-step differentiation procedures.In conclusion, the differentiation of stem cells to KLCs is feasible and KLCs were used in experimental, preclinical, and clinical trials. However, the translation of KLCs from in vitro investigational system to clinically valuable cells is challenging and extremely slow.

Enhancing differentiation of menstrual blood-derived stem cells into female germ cells using a bilayer amniotic membrane and nano-fibrous fibroin scaffold

Three-dimensional nanofiber scaffolds offer a promising method for simulating in vivo conditions within the laboratory. This study aims to investigate the influence of a bilayer amniochorionic membrane/nanofibrous fibroin scaffold on the differentiation of human menstrual blood mesenchymal stromal/stem cells (MenSCs) into female germ cells. MenSCs were isolated and assigned to four culture groups: (i) MenSCs co-cultured with granulosa cells (GCs) using the scaffold (3D-T group), (ii) MenSCs using the scaffold alone (3D-C group), (iii) MenSCs co-cultured only with GCs (2D-T group), and (iv) MenSCs without co-culture or scaffold (2D-C group). Both MenSCs and GCs were independently cultured for two weeks before co-culturing was initiated. Flow cytometry was employed to characterize MenSCs based on positive markers (CD73, CD90, and CD105) and negative markers (CD45 and CD133). Additionally, flow cytometry and immunocytochemistry were used to characterize the GCs. Differentiated MenSCs were analyzed using real-time PCR and immunostaining. The real-time PCR results demonstrated significantly higher levels of VASA expression in the 3D-T group compared to the 3D-C, 2D-T, and 2D-C groups. Similarly, the SCP3 mRNA level in the 3D-T group was notably elevated compared to the 3D-C, 2D-T, and 2D-C groups. Moreover, the expression of GDF9 was significantly higher in the 3D-T group when compared to the 3D-C, 2D-T, and 2D-C groups. Immunostaining results revealed a lack of signal for VASA, SCP3, or GDF9 markers in the 2D-T group, while some cells in the 3D-T group exhibited positive staining for all these proteins. These findings suggest that the combination of a bilayer amniochorionic membrane/nanofibrous fibroin scaffold with co-culturing GCs facilitates the differentiation of MenSCs into female germ cells.

Emerging Strategies for the Biofabrication of Multilayer Composite Amniotic Membranes for Biomedical Applications

The amniotic membrane (AM) is the innermost part of the fetal placenta, which surrounds and protects the fetus. Due to its structural components (stem cells, growth factors, and proteins), AMs display unique biological properties and are a widely available and cost-effective tissue. As a result, AMs have been used for a century as a natural biocompatible dressing for healing corneal and skin wounds. To further increase its properties and expand its applications, advanced hybrid materials based on AMs have recently been developed. One existing approach is to combine the AM with a secondary material to create composite membranes. This review highlights the increasing development of new multilayer composite-based AMs in recent years and focuses on the benefits of additive manufacturing technologies and electrospinning, the most commonly used strategy, in expanding their use for tissue engineering and clinical applications. The use of AMs and multilayer composite-based AMs in the context of nerve regeneration is particularly emphasized and other tissue engineering applications are also discussed. This review highlights that these electrospun multilayered composite membranes were mainly created using decellularized or de-epithelialized AMs, with both synthetic and natural polymers used as secondary materials. Finally, some suggestions are provided to further enhance the biological and mechanical properties of these composite membranes.

Fabrication and multiscale modeling of polycaprolactone/amniotic membrane electrospun nanofiber scaffolds for wound healing

BACKGROUND

Enhancing the efficiency of cell-based skin tissue engineering (TE) approaches is possible via designing electrospun scaffolds possessing natural materials like amniotic membrane (AM) with wound healing characteristics. Concentrating on this aim, we fabricated innovative polycaprolactone (PCL)/AM scaffolds through the electrospinning process.

METHODS

The manufactured structures were characterized by employing scanning electron microscope (SEM), attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, tensile testing, Bradford protein assay, etc. In addition, the mechanical properties of scaffolds were simulated by the multiscale modeling method.

RESULTS

As a result of conducting various tests, it was concluded that the uniformity and distribution of fibers decreased with an increase in the amniotic content. Furthermore, PCL-AM scaffolds contained amniotic and PCL characteristic bands. In the case of protein release, greater content of AM led to the release of higher amounts of collagen. Tensile testing revealed that scaffolds' ultimate strength increased when the AM content augmented. The multiscale modeling demonstrated that the scaffold had elastoplastic behavior. In order to assess cellular attachment, viability, and differentiation, human adipose-derived stem cells (ASCs) were seeded on the scaffolds. In this regard, SEM and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays showed significant cellular proliferation and viability on the proposed scaffolds, and these analyses illustrated that higher cell survival and adhesion could be achieved when scaffolds possessed a larger amount of AM. After 21 days of cultivation, particular keratinocyte markers, such as keratin I and involucrin, were identified through utilizing immunofluorescence and real-time polymerase chain reaction (PCR) tests. The markers' expressions were higher in the PCL-AM scaffold with a ratio of 90:10 v v-1 compared with the PCL-epidermal growth factor (EGF) structure. Moreover, the presence of AM in the scaffolds resulted in the keratinogenic differentiation of ASCs even without employing EGF. Consequently, this state-of-the-art experiment suggests that the PCL-AM scaffold can be a promising candidate in skin bioengineering.

CONCLUSION

This study showed that mixing AM with PCL, a widely used polymer, in different concentrations can overcome PCL disadvantages such as high hydrophobicity and low cellular compatibility.

Recent advances in decellularized biomaterials for wound healing

The skin is one of the most essential organs in the human body, interacting with the external environment and shielding the body from diseases and excessive water loss. Thus, the loss of the integrity of large portions of the skin due to injury and illness may lead to significant disabilities and even death. Decellularized biomaterials derived from the extracellular matrix of tissues and organs are natural biomaterials with large quantities of bioactive macromolecules and peptides, which possess excellent physical structures and sophisticated biomolecules, and thus, promote wound healing and skin regeneration. Here, we highlighted the applications of decellularized materials in wound repair. First, the wound-healing process was reviewed. Second, we elucidated the mechanisms of several extracellular matrix constitutes in facilitating wound healing. Third, the major categories of decellularized materials in the treatment of cutaneous wounds in numerous preclinical models and over decades of clinical practice were elaborated. Finally, we discussed the current hurdles in the field and anticipated the future challenges and novel avenues for research on decellularized biomaterials-based wound treatment.

Epigenetic Modification Factors and microRNAs Network Associated with Differentiation of Embryonic Stem Cells and Induced Pluripotent Stem Cells toward Cardiomyocytes: A Review

More research is being conducted on myocardial cell treatments utilizing stem cell lines that can develop into cardiomyocytes. All of the forms of cardiac illnesses have shown to be quite amenable to treatments using embryonic (ESCs) and induced pluripotent stem cells (iPSCs). In the present study, we reviewed the differentiation of these cell types into cardiomyocytes from an epigenetic standpoint. We also provided a miRNA network that is devoted to the epigenetic commitment of stem cells toward cardiomyocyte cells and related diseases, such as congenital heart defects, comprehensively. Histone acetylation, methylation, DNA alterations, N6-methyladenosine (m⁶a) RNA methylation, and cardiac mitochondrial mutations are explored as potential tools for precise stem cell differentiation.

Endometriosis Stem Cells as a Possible Main Target for Carcinogenesis of Endometriosis-Associated Ovarian Cancer (EAOC)

Endometriosis is a serious recurrent disease impairing the quality of life and fertility, and being a risk for some histologic types of ovarian cancer defined as endometriosis-associated ovarian cancers (EAOC). The presence of stem cells in the endometriotic foci could account for the proliferative, migrative and angiogenic activity of the lesions. Their phenotype and sources have been described. The similarly disturbed expression of several genes, miRNAs, galectins and chaperones has been observed both in endometriotic lesions and in ovarian or endometrial cancer. The importance of stem cells for nascence and sustain of malignant tumors is commonly appreciated. Although the proposed mechanisms promoting carcinogenesis leading from endometriosis into the EAOC are not completely known, they have been discussed in several articles. However, the role of endometriosis stem cells (ESCs) has not been discussed in this context. Here, we postulate that ESCs may be a main target for the carcinogenesis of EAOC and present the possible sequence of events resulting finally in the development of EAOC.

Applications of the amniotic membrane in tissue engineering and regeneration: the hundred-year challenge

The amniotic membrane (Amnio-M) has various applications in regenerative medicine. It acts as a highly biocompatible natural scaffold and as a source of several types of stem cells and potent growth factors. It also serves as an effective nano-reservoir for drug delivery, thanks to its high entrapment properties. Over the past century, the use of the Amnio-M in the clinic has evolved from a simple sheet for topical applications for skin and corneal repair into more advanced forms, such as micronized dehydrated membrane, amniotic cytokine extract, and solubilized powder injections to regenerate muscles, cartilage, and tendons. This review highlights the development of the Amnio-M over the years and the implication of new and emerging nanotechnology to support expanding its use for tissue engineering and clinical applications.

The remarkable effect of menstrual blood stem cells seeded on bilayer scaffold composed of amniotic membrane and silk fibroin aiming to promote wound healing in diabetic mice

INTRODUCTION

Impaired chronic wound healing frequently occurs in diabetic patients. We hypothesized that menstrual blood-derived mesenchymal stem cells (MenSCs) in combination with bilayer scaffold consisted of human amniotic membrane (AM) and electrospun silk fibroin nanofibers could potentially promote wound healing in diabetic mice.

METHODS & METHODS

Two bilateral full-thickness wounds were created on dorsal skin of type-1 diabetic mice model and animals were equally divided in four groups including: no-treatment group (NT), amniotic membrane treated group (AM), bilayer scaffold treated group (bSC), and MenSCs-seeded bilayer scaffold treated group (bSC + MenSCs). Wound healing evaluations were performed at 3, 7, and 14 days after their treatment. The wound healing was analyzed by macroscopic and microscopic evaluations, and immunofluorescence staining of involucrin (IVL), type III collagen, CD31/ von Willebrand factor (vWF), and PGP9.5 were performed. Furthermore, number of neutrophils and macrophages and subpopulation of macrophages were assessed. In addition, the expression of Egr2, Mmp9, CXCL12, IDO1, Ptgs2 and VEGFA transcripts involved in wound repair were also analyzed.

RESULTS

After 14 days, the best epidermal and dermal regeneration belonged to the cases received bSC + MenSCs as wound dressing. Moreover, the wound healing was typically faster in this group compared to other groups. Immunofluorescence evaluation represented higher levels of CD31 and VWF, higher ratio of M2/M1 macrophages, greater expression of IVL, and higher levels of the PGP9.5 in the bSC + MenSCs group in comparison with other groups. Expression analysis of assessed genes also supported assumption of more regeneration and healing in the bSC + MenSCs group versus other groups.

CONCLUSION

These results indicate that enhanced immunomodulatory and reparative properties of MenSCs in conjunction with bilayer scaffold specified this cellular skin substitute for modulating wound chronicity and contribution to resolution of wound healing process in diabetic ulcer.

Membranous Extracellular Matrix-Based Scaffolds for Skin Wound Healing

Membranous extracellular matrix (ECM)-based scaffolds are one of the most promising biomaterials for skin wound healing, some of which, such as acellular dermal matrix, small intestinal submucosa, and amniotic membrane, have been clinically applied to treat chronic wounds with acceptable outcomes. Nevertheless, the wide clinical applications are always hindered by the poor mechanical properties, the uncontrollable degradation, and other factors after implantation. To highlight the feasible strategies to overcome the limitations, in this review, we first outline the current clinical use of traditional membranous ECM scaffolds for skin wound healing and briefly introduce the possible repair mechanisms; then, we discuss their potential limitations and further summarize recent advances in the scaffold modification and fabrication technologies that have been applied to engineer new ECM-based membranes. With the development of scaffold modification approaches, nanotechnology and material manufacturing techniques, various types of advanced ECM-based membranes have been reported in the literature. Importantly, they possess much better properties for skin wound healing, and would become promising candidates for future clinical translation.

Endometrial stem/progenitor cells and their roles in immunity, clinical application, and endometriosis

Endometrial stem/progenitor cells have been proved to exist in periodically regenerated female endometrium and can be divided into three categories: endometrial epithelial stem/progenitor cells, CD140b+CD146+ or SUSD2+ endometrial mesenchymal stem cells (eMSCs), and side population cells (SPs). Endometrial stem/progenitor cells in the menstruation blood are defined as menstrual stem cells (MenSCs). Due to their abundant sources, excellent proliferation, and autotransplantation capabilities, MenSCs are ideal candidates for cell-based therapy in regenerative medicine, inflammation, and immune-related diseases. Endometrial stem/progenitor cells also participate in the occurrence and development of endometriosis by entering the pelvic cavity from retrograde menstruation and becoming overreactive under certain conditions to form new glands and stroma through clonal expansion. Additionally, the limited bone marrow mesenchymal stem cells (BMDSCs) in blood circulation can be recruited and infiltrated into the lesion sites, leading to the establishment of deep invasive endometriosis. On the other hand, cell derived from endometriosis may also enter the blood circulation to form circulating endometrial cells (CECs) with stem cell-like properties, and to migrate and implant into distant tissues. In this manuscript, by reviewing the available literature, we outlined the characteristics of endometrial stem/progenitor cells and summarized their roles in immunoregulation, regenerative medicine, and endometriosis, through which to provide some novel therapeutic strategies for reproductive and cancerous diseases.

A Review on Modifications of Amniotic Membrane for Biomedical Applications

The amniotic membrane (AM) is the innermost layer of the fetal placenta, which surrounds and protects the fetus. Its unique structure, in addition to its physical and biological properties, makes it a useful substance in many applications related to regenerative medicine. The use of this fantastic substance with a century-old history has produced remarkable results in vivo, in vitro, and even in clinical studies. While the intact or preserved AM is widely used for these purposes, the addition of further modifications to AM can be considered as a relatively new subject in its applications. These modifications are applied to improve AM properties, ease of handling, and durability. Here, we will discuss the cases in which AM has undergone additional modifications besides the required processes for sterilization and preservation. In this article, we have categorized these modifications and discussed their applications and results.

Endometrial and Menstrual Blood Mesenchymal Stem/Stromal Cells: Biological Properties and Clinical Application

A highly proliferative mesenchymal stem/stromal cell (MSC) population was recently discovered in the dynamic, cyclically regenerating human endometrium as clonogenic stromal cells that fulfilled the International Society for Cellular Therapy (ISCT) criteria. Specific surface markers enriching for clonogenic endometrial MSC (eMSC), CD140b and CD146 co-expression, and the single marker SUSD2, showed their perivascular identity in the endometrium, including the layer which sheds during menstruation. Indeed, cells with MSC properties have been identified in menstrual fluid and commonly termed menstrual blood stem/stromal cells (MenSC). MenSC are generally retrieved from menstrual fluid as plastic adherent cells, similar to bone marrow MSC (bmMSC). While eMSC and MenSC share several biological features with bmMSC, they also show some differences in immunophenotype, proliferation and differentiation capacities. Here we review the phenotype and functions of eMSC and MenSC, with a focus on recent studies. Similar to other MSC, eMSC and MenSC exert immunomodulatory and anti-inflammatory impacts on key cells of the innate and adaptive immune system. These include macrophages, T cells and NK cells, both in vitro and in small and large animal models. These properties suggest eMSC and MenSC as additional sources of MSC for cell therapies in regenerative medicine as well as immune-mediated disorders and inflammatory diseases. Their easy acquisition via an office-based biopsy or collected from menstrual effluent makes eMSC and MenSC attractive sources of MSC for clinical applications. In preparation for clinical translation, a serum-free culture protocol was established for eMSC which includes a small molecule TGFβ receptor inhibitor that prevents spontaneous differentiation, apoptosis, senescence, maintains the clonogenic SUSD2+ population and enhances their potency, suggesting potential for cell-therapies and regenerative medicine. However, standardization of MenSC isolation protocols and culture conditions are major issues requiring further research to maximize their potential for clinical application. Future research will also address crucial safety aspects of eMSC and MenSC to ensure these protocols produce cell products free from tumorigenicity and toxicity. Although a wealth of data on the biological properties of eMSC and MenSC has recently been published, it will be important to address their mechanism of action in preclinical models of human disease.

Epithelial differentiation of human adipose-derived stem cells (hASCs) undergoing three-dimensional (3D) cultivation with collagen sponge scaffold (CSS) via an indirect co-culture strategy

BACKGROUND

Three-dimensional (3D) cultivation with biomaterials was proposed to facilitate stem cell epithelial differentiation for wound healing. However, whether human adipose-derived stem cells (hASCs) on collagen sponge scaffold (CSS) better differentiate to keratinocytes remains unclear.

METHODS

3D cultivation with CSS on hASC epidermal differentiation co-cultured with HaCaT cells at air-liquid interface (ALI) was compared with two-dimensional (2D) form and cultivation without "co-culture" or "ALI." Cellular morphology, cell adhesion, and growth condition were evaluated, followed by the protein and gene expression of keratin 14 (K14, keratinocyte specific marker).

RESULTS

Typical cobblestone morphology of keratinocytes was remarkably observed in co-cultured hASCs at ALI, but those seeded on the CSS exhibited more keratinocyte-like cells under an invert microscope and scanning electron microscope. Desired cell adhesion and proliferation were confirmed in 3D differentiation groups by rhodamine-labeled phalloidin staining, consistent with H&E staining. Compared with those cultured in 2D culture system or without "ALI," immunofluorescence staining and gene expression analysis revealed hASCs co-cultured over CSS expressed K14 at higher levels at day 15.

CONCLUSIONS

CSS is positive to promote epithelial differentiation of hASCs, which will foster a deeper understanding of artificial dermis in skin wound healing and regeneration.

Differentiation of Menstrual Blood Stem Cells into Keratinocyte-Like Cells on Bilayer Nanofibrous Scaffold

Skin tissue engineering is a high-throughput technology to heal the wounds. Already, considerable advances have been achieved using stem cells for wound healing applications. Menstrual blood stem cell (MenSC) is an available and accessible source of stem cells that have differentiation potential into a wide range of lineages like keratinocytes. Extracellular matrix like substratum plays an impressive role in skin regeneration as an attachment site for stem cells by transmitting the bioactive signals and provoking stem cells to differentiate into keratinocyte lineage. The biomimetic nanofibrous scaffold especially in bilayer format has been extensively utilized to develop skin equivalents. This chapter explains detailed protocols of keratinocyte differentiation of MenSCs on bilayer scaffold comprising amniotic membrane and fibroin nanofibers. The isolated MenSCs are seeded on the nanofibers and subsequently differentiated into keratinocyte lineage in co-culture with foreskin-derived keratinocytes. Immunofluorescence staining is used to evaluate the development of seeded MenSCs in bilayer scaffold into keratinocyte-like cells.