In toto differentiation of human amniotic membrane towards the Schwann cell lineage

Application of the Human Amniotic Membrane as an Adjuvant Therapy for the Treatment of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related morbidity and mortality worldwide. Current therapeutic approaches suffer significant side effects and lack of clear understanding of their molecular targets. Recent studies reported the anticancer effects, immunomodulatory properties, and antiangiogenic effects of the human amniotic membrane (hAM). hAM is a transparent protective membrane that surrounds the fetus. Preclinical studies showed pro-apoptotic and antiproliferative properties of hAM treatment on cancer cells. Herein, we present the latest findings of the application of the hAM in combating HCC tumorigenesis and the underlying molecular pathogenies and the role of transforming growth factor-beta (TGFβ), P53, WNT/beta-catenin, and PI3K/AKT pathways. The emerging clinical applications of hAM in cancer therapy provide evidence for its diverse and unique features and suitability for the management of a wide range of pathological conditions.

Effects of Adipose-Derived Mesenchymal Stem Cells and Human Amniotic Membrane on Sciatic Nerve Repair in Rats

Background: Peripheral nerve injuries remain a great challenge for microsurgery despite the significant progress in recent decades. The current gold standard is autogenous nerve grafting with a success rate as low as 50% in long gaps. Current studies have focused on finding alternative methods for bridging nerve defects. Previous data have demonstrated the role of human amniotic membrane in stimulating neural regeneration. On the other hand, adipose-derived mesenchymal stem cells can differentiate into all three germ layers and could support nerve repair. The purpose of this study was to compare the role of the human amniotic membrane with and without adipose tissue stem cells in sciatic nerve injury with gap in rats. Objectives: We aimed to evaluate the effectiveness of the human amniotic membrane with and without adipose-derived mesenchymal stem cells in sciatic nerve injury with gap in rats. Methods: Twenty-four male Wistar rats in four random groups were used in our study. In the first group, the nerve gap was repaired using the inverse resected nerve segment (Control group), the second group was repaired with a human amniotic membrane (AM group), the third group was repaired with an amnion sheet with seeded adipose-derived mesenchymal stem cells (AM/ADMSCs group), and the last group was not repaired, and both stumps were sutured to muscles. Results: All the animals underwent the procedures and survived without complication. The sciatic function index and hot plate test results were significantly improved in the AM and AM/ADMSCs groups compared to the Control group (as a gold standard of care) (P>0.05). Based on histopathology findings, regenerative nerve fibers were seen in the implanted area of both AM and AM/ADMSCs groups; however, nerve fibers were surrounded by significant fibrosis (scar formation) in the AM/ADMSCs group. The axon count in the Control group was significantly higher than both experimental groups (P < 0.01). Conclusions: Our study showed the role of amniotic membrane in the promotion of nerve regeneration in sciatic nerve injury with a gap, but adding adipose-derived mesenchymal stem cells not only has no extra benefits, but also causes more tissue scar.

Functional and Structural Changes Following Corneal Neurotisation in the Management of Neurotrophic Keratopathy: UK Single Centre Series

OBJECTIVE

To report the functional and anatomical outcomes including structural changes in corneal nerve density and morphology using in vivo confocal microscopy (IVCM) after corneal neurotisation in patients with neurotrophic keratopathy (NK), using a sural nerve graft.

PATIENTS AND METHODS

Prospective study of patients undergoing corneal neurotisation for NK. Functional outcomes were measured through visual acuity, slit-lamp examination of corneal and conjunctival staining, tear production (Schirmer's 1 test), tear film break-up time, tear film meniscus height, quality and osmolarity, central corneal thickness and corneal sensation using Cochet-Bonnet esthesiometry. Structural outcomes were assessed from changes in corneal nerve density and morphology with IVCM. Subjective outcomes were assessed using VFQ-25 and latest telephonic consultation.

RESULTS

Between February 2016 and April 2018, 11 corneal neurotisations were performed on 11 patients (3 males, 8 females). Median age was 43 (range 25-62) years. Mean follow-up was 14.5 (range, 4-36) months. Snellen visual acuity improved in 6 patients, corneal and conjunctival staining decreased in 10, tear film breakup time increased in 9, tear meniscus height increased in 7, Schirmers test readings increased in 4, tear film osmolarity reduced in 8 and central corneal thickness increased in 10 patients. Corneal sensation improved in nine patients. Complete IVCM data were available in five cases and demonstrated an improvement of corneal nerve density and length at 12 months.

CONCLUSION

This series confirms the fact that the outcomes of this technique are reproducible and that corneal neurotisation surgery helps restore trophic nerve function more consistently than touch-related sensation.

Amnion-Derived Multipotent Progenitor Cells Suppress Experimental Optic Neuritis and Myelitis

The human amnion has been used for decades in wound healing, particularly burns. Amnion epithelial cells (AECs) have been the focus of extensive research based on their possible pluripotent differentiation ability. A novel, cultured cell population derived from AECs, termed human amnion-derived multipotent progenitor (AMP) cells, secrete numerous cytokines and growth factors that enhance tissue regeneration and reduce inflammation. This AMP cell secretome, termed ST266, is a unique biological solution that accumulates in eyes and optic nerves following intranasal delivery, resulting in selective suppression of optic neuritis in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis, but not myelitis at the administered dose. We tested the hypothesis that systemic AMP cell administration could suppress both optic neuritis and myelitis in EAE. Intravenous and intraperitoneal administration of AMP cells significantly reduced ascending paralysis and attenuated visual dysfunction in EAE mice. AMP cell treatment increased retinal ganglion cell (RGC) survival and decreased optic nerve inflammation, with variable improvement in optic nerve demyelination and spinal cord inflammation and demyelination. Results show systemic AMP cell administration inhibits RGC loss and visual dysfunction similar to previously demonstrated effects of intranasally delivered ST266. Importantly, AMP cells also promote neuroprotective effects in EAE spinal cords, marked by reduced paralysis. Protective effects of systemically administered AMP cells suggest they may serve as a potential novel treatment for multiple sclerosis.

Perinatal tissues and cells in tissue engineering and regenerative medicine

Perinatal tissues are an abundant source of human extracellular matrix proteins, growth factors and stem cells with proved potential use in a wide range of therapeutic applications. Due to their placental origin, these tissues possess unique biological properties, including being angiogenic, anti-inflammatory, anti-fibrotic, anti-microbial and immune privileged. Additionally, as a temporary organ, placenta is usually discarded as a medical waste, thus providing an easily available, cost effective, 'unlimited' and ethical source of raw materials. Although some of these tissues, such as the amniotic membrane and umbilical cord, have been used in clinical practices, most of them continue to be highly under explored. This review aims to outline the most relevant applications of perinatal tissues as a source of biomaterials and stem cells in the exciting fields of tissue engineering and regenerative medicine (TERM), as well as highlight how these solutions can be used to overcome the shortage of adequate scaffolds and cell sources that currently hampers the translation of TERM strategies towards clinical settings. STATEMENT OF SIGNIFICANCE: Stem cells and extracellular matrix derived from perinatal tissues such as placenta and umbilical cord, have drawn great attention for use in a wide variety of applications in the biomedical field. Due to their origin, these tissues possess unique biological properties, including being angiogenic, anti-inflammatory, anti-fibrotic, anti-microbial and immune privileged. Also they are typically considered medical waste, thus providing an easily available, cost effective, 'unlimited' and ethical source of raw materials. This work aims to present and discuss the most relevant applications of perinatal tissues as a source of biomaterials and stem cells in the exciting fields of tissue engineering and regenerative medicine (TERM).

Critical Impact of Human Amniotic Membrane Tension on Mitochondrial Function and Cell Viability In Vitro

Amniotic cells show exciting stem cell features, which has led to the idea of using living cells of human amniotic membranes (hAMs) in toto for clinical applications. However, under common cell culture conditions, viability of amniotic cells decreases rapidly, whereby reasons for this decrease are unknown so far. Recently, it has been suggested that loss of tissue tension in vivo leads to apoptosis. Therefore, the aim of this study was to investigate the effect of tissue distention on the viability of amniotic cells in vitro. Thereby, particular focus was put on vital mitochondria-linked parameters, such as respiration and ATP synthesis. Biopsies of hAMs were incubated for 7–21 days either non-distended or distended. We observed increased B-cell lymphoma 2-associated X protein (BAX)/B-cell lymphoma (BCL)-2 ratios in non-distended hAMs at day seven, followed by increased caspase 3 expression at day 14, and, consequently, loss of viability at day 21. In contrast, under distention, caspase 3 expression increased only slightly, and mitochondrial function and cellular viability were largely maintained. Our data suggest that a mechano-sensing pathway may control viability of hAM cells by triggering mitochondria-mediated apoptosis upon loss of tension in vitro. Further studies are required to elucidate the underlying molecular mechanisms between tissue distention and viability of hAM cells.

Stem-cell-based therapies to enhance peripheral nerve regeneration

Peripheral nerve injury remains a major cause of morbidity in trauma patients. Despite advances in microsurgical techniques and improved understanding of nerve regeneration, obtaining satisfactory outcomes after peripheral nerve injury remains a difficult clinical problem. There is a growing body of evidence in preclinical animal studies demonstrating the supportive role of stem cells in peripheral nerve regeneration after injury. The characteristics of both mesoderm-derived and ectoderm-derived stem cell types and their role in peripheral nerve regeneration are discussed, specifically focusing on the presentation of both foundational laboratory studies and translational applications. The current state of clinical translation is presented, with an emphasis on both ethical considerations of using stems cells in humans and current governmental regulatory policies. Current advancements in cell-based therapies represent a promising future with regard to supporting nerve regeneration and achieving significant functional recovery after debilitating nerve injuries.

A single-center, retrospective review of robot-assisted laparoscopic prostatectomy with and without cryopreserved umbilical cord allograft in improving continence recovery

The objective of this study was to evaluate the safety and effectiveness of cryopreserved umbilical cord (UC) allograft as a nerve wrap around the neurovascular bundle (NVB) in accelerating return to continence after radical prostatectomy. A single-center, retrospective study was performed on 200 patients who underwent bilateral, nerve-sparing robot-assisted radical prostatectomy (RARP) with and without placement of UC around the NVBs (n = 100/group). Patients were excluded if they had previous simple or transurethral prostatectomy or history of pelvic radiation. Post-operative continence, defined as 0 or 1 safety pad, was analyzed between groups at 1, 3, 6, and 12 months. Complications, biochemical recurrence and adverse events were assessed to determine safety. Patients who underwent RARP with UC were significantly more likely to be continent at 1 month (65% vs. 44%, p = 0.018), 3 months (83% vs. 70%, p = 0.03), and 12 months (97% vs. 87%, p = 0.009). Sample stratification revealed that UC is beneficial for obese patients and those > 60 years, both of which are high risk for post-RARP incontinence. Biochemical failure was noted in 2 (UC) and 4 (control) patients. No adverse events or complications related to UC were observed. The results suggest that UC allograft is safe and accelerates continence recovery in post-RARP patients. Prospective, randomized trials are warranted.

Update on corneal neurotisation

Corneal neurotisation describes surgical restoration of nerve growth into the cornea to restore corneal sensation and trophic function. It represents an exciting and effective emerging treatment for neurotrophic keratopathy. Techniques described to date involve either direct nerve transfer or an interpositional nerve graft coapted to a healthy donor nerve. We review the experience to date with particular emphasis on a detailed review of techniques, outcomes and current thoughts.

The amnion muscle combined graft (AMCG) conduits in nerves repair: an anatomical and experimental study on a rat model

The amnion muscle combined graft (AMCG) conduits showed good clinical results in peripheral nerves gap repair. It combines the human amniotic membrane with autologous skeletal muscle fibres. These results seem attributable to the biological characteristics of human amniotic membrane: Pluripotency, anti-inflammatory and low immunogenicity.We here evaluate the final outcome of nerve regeneration morphologically and functionally, across the AMCG compared to nerve autograft. Fourteen Wistar rats were divided into two groups: In Group A, including 6 rats, the left forelimb was treated performing a 1.5 cm length gap on median nerve that was then reconstructed with a reverse autograft. In Group B, including 8 rats, the gap was reconstructed with AMCG. Functional results were evaluated at 30, 60 and 90 days performing grasping tests. Morphological and stereological analyses were performed at T90 using high-resolution light microscopy and design-based stereology. The AMCG conduits revealed nerve fibres regeneration and functional recovery. Functional recovery was observed in both groups with AMCG conduits group showing lower values and a regeneration of median nerves with more myelinated fibres with the same axon size, but thinner myelin than the autograft group. Though the autograft remains the gold standard to restore wide nerve gaps, the AMCG conduit has proved to be effective in enabling nerve regeneration through a critical rat's nerve gap of 15 mm. These findings empirically support the great clinical results obtained using AMCG conduit to restore traumatic nerve's gap from 3 to 6 cm of mixed forearm nerves.

Laminin-chitosan-PLGA conduit co-transplanted with Schwann and neural stem cells to repair the injured recurrent laryngeal nerve

The aim of the present study was to assess the possibility and efficacy of utilizing a laminin-chitosan-poly (lactic-co-glycolic acid), otherwise known as laminin-chitosan-PLGA, nerve conduit with the co-transplantation of Schwann and neural stem cells to repair peripheral nerve defects. Previous in vitro experiments have demonstrated that the three-dimensional structure of the built in fiber filament electrospinning of laminin-chitosan-PLGA nerve conduit is beneficial to the migration and regeneration of nerve cells, and has notable mechanical strength and plasticity. It is able to provide support in the neural tissue regeneration process, and has the ability to degrade itself once peripheral nerves complete their regeneration, providing more advantages than other biological and synthetic materials. In the present study, 132 female Sprague Dawley rats were used to establish an animal model of laryngeal nerve injury, and the rats were randomly divided into six groups for experimentation. The nerve conduit was prepared and co-cultured with Schwann and neural stem cells, and micro-surgical techniques were used to repair the 5-mm-long recurrent laryngeal nerve injuries. Functional and histological assessments were performed at 8 and 12 weeks post-surgery, respectively. The results revealed that the laminin-chitosan-PLGA nerve conduit combined with Schwann and neural stem cells was able to promote nerve regeneration (P<0.05), and its effect was superior to those of the autograft (P<0.05). The results of the present study suggest that this is the ideal method for repairing peripheral nerve defects, and cells in the graft may promote nerve regeneration.

Treatment outcomes in the DRy Eye Amniotic Membrane (DREAM) study

Purpose

To evaluate the efficacy of cryopreserved amniotic membrane (CAM) in reducing signs and symptoms of dry eye disease (DED) in a large patient population.

Methods

A retrospective chart review at 10 clinical sites was done of patients with refractory DED who received CAM and completed at least 3 months of follow-up. Data collected were demographics; medical history including previous and current ocular treatment, diagnosis, clinical presentations, comorbidity, duration and frequency of treatment with CAM; and concomitant medications. The primary outcome was the change in dry eye workshop (DEWS) score after treatment.

Results

A total of 97 eyes of 84 patients exhibited severe dry eye despite maximal medical treatments including topical artificial tears, cyclosporine-A, serum, antibiotics, and steroids. Patients manifested with superficial punctate keratitis (86%), filamentary keratitis (13%), exposure keratitis (19%), neurotrophic keratitis (2%), and corneal epithelial defect (7%). After CAM treatment for 5.4±2.8 days, 74 (88%) patients demonstrated an improved ocular surface along with a notable reduction of the severity as the overall DEWS score was significantly reduced from 3.25±0.5 at baseline to 1.44±0.6 at 1 week, 1.45±0.6 at 1 month, and 1.47±0.6 at 3 months (p<0.001). Ten eyes (10%) required repeated treatment to complete healing. Apart from discomfort during CAM placement, there were no adverse events.

Conclusion

Placement of CAM is promising to enhance the recovery of ocular surface health and reduce signs and symptoms in patients with moderate-to-severe DED.

Human Perinatal-Derived Biomaterials

Human perinatal tissues have been used for over a century as allogeneic biomaterials. Due to their advantageous properties including angiogenecity, anti-inflammation, anti-microbial, and immune privilege, these tissues are being utilized for novel applications across wide-ranging medical disciplines. Given continued clinical success, increased adoption of perinatal tissues as a disruptive technology platform has allowed for significant penetration into the multi-billion dollar biologics market. Here, we review current progress and future applications of perinatal biomaterials, as well as associated regulatory issues.

Corneal Nerve Regeneration after Self-Retained Cryopreserved Amniotic Membrane in Dry Eye Disease

Purpose

To evaluate the efficacy of self-retained cryopreserved amniotic membrane (CAM) in promoting corneal nerve regeneration and improving corneal sensitivity in dry eye disease (DED).

Methods

In this prospective randomized clinical trial, subjects with DED were randomized to receive CAM (study group) or conventional maximum treatment (control). Changes in signs and symptoms, corneal sensitivity, topography, and in vivo confocal microscopy (IVCM) were evaluated at baseline, 1 month, and 3 months.

Results

Twenty subjects (age 66.9 ± 8.9) were enrolled and 17 completed all follow-up visits. Signs and symptoms were significantly improved in the study group yet remained constant in the control. IVCM showed a significant increase in corneal nerve density in the study group (12,241 ± 5083 μm/mm² at baseline, 16,364 ± 3734 μm/mm² at 1 month, and 18,827 ± 5453 μm/mm² at 3 months, p = 0.015) but was unchanged in the control. This improvement was accompanied with a significant increase in corneal sensitivity (3.25 ± 0.6 cm at baseline, 5.2 ± 0.5 cm at 1 month, and 5.6 ± 0.4 cm at 3 months, p < 0.001) and corneal topography only in the study group.

Conclusions

Self-retained CAM is a promising therapy for corneal nerve regeneration and accelerated recovery of the ocular surface health in patients with DED. The study is registered at clinicaltrials.gov with trial identifier: NCT02764814.

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

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

Decellularized human placenta chorion matrix as a favorable source of small-diameter vascular grafts

Biomaterials based on decellularized tissues are increasingly attracting attention as functional alternatives to other natural or synthetic materials. However, a source of non-cadaver human allograft material would be favorable. Here we establish a decellularization method of vascular tissue from cryopreserved human placenta chorionic plate starting with an initial freeze-thaw step followed by a series of chemical treatments applied with a custom-made perfusion system. This novel pulsatile perfusion set-up enabled us to successfully decellularize the vascular tissue with lower concentrations of chemicals and shorter exposure times compared to a non-perfusion process. The decellularization procedure described here lead to the preservation of the native extracellular matrix architecture and the removal of cells. Quantitative analysis revealed no significant changes in collagen content and a retained glycosaminoglycan content of approximately 29%. In strain-to-failure tests, the decellularized grafts showed similar mechanical behavior compared to native controls. In addition, the mechanical values for ultimate tensile strength and stiffness were in an acceptable range for in vivo applications. Furthermore, biocompatibility of the decellularized tissue and its recellularizationability to serve as an adequate substratum for upcoming recellularization strategies using primary human umbilical vein endothelial cells (HUVECs) was demonstrated. HUVECs cultured on the decellularized placenta vessel matrix performed endothelialization and maintained phenotypical characteristics and cell specific expression patterns. Overall, the decellularized human placenta vessels can be a versatile tool for experimental studies on vascularization and as potent graft material for future in vivo applications.

STATEMENT OF SIGNIFICANCE

In the US alone more than 1million vascular grafts are needed in clinical practice every year. Despite severe disadvantages, such as donor site morbidity, autologous grafting from the patient's own arteries or veins is regarded as the gold standard for vascular tissue repair. Besides, strategies based on synthetic or natural materials have shown limited success. Tissue engineering approaches based on decellularized tissues are regarded as a promising alternative to clinically used treatments to overcome the observed limitations. However, a source for supply of non-cadaver human allograft material would be favorable. Here, we established a decellularization method of vascular tissue from the human placenta chorionic plate, a suitable human tissue source of consistent quality. The decellularized human placenta vessels can be a potent graft material for future in vivo applications and furthermore might be a versatile tool for experimental studies on vascularization.

Enzymatic and non-enzymatic isolation systems for adipose tissue-derived cells: current state of the art

In the past decade, adipose tissue became a highly interesting source of adult stem cells for plastic surgery and regenerative medicine. The isolated stromal vascular fraction (SVF) is a heterogeneous cell population including the adipose-derived stromal/stem cells (ASC), which showed regenerative potential in several clinical studies and trials. SVF should be provided in a safe and reproducible manner in accordance with current good manufacturing practices (cGMP). To ensure highest possible safety for patients, a precisely defined procedure with a high-quality control is required. Hence, an increasing number of adipose tissue-derived cell isolation systems have been developed. These systems aim for a closed, sterile, and safe isolation process limiting donor variations, risk for contaminations, and unpredictability of the cell material. To isolate SVF from adipose tissue, enzymes such as collagenase are used. Alternatively, in order to avoid enzymes, isolation systems using physical forces are available. Here, we provide an overview of known existing enzymatic and non-enzymatic adipose tissue-derived cell isolation systems, which are patented, published, or already on the market.

Accelerated Restoration of Ocular Surface Health in Dry Eye Disease by Self-Retained Cryopreserved Amniotic Membrane

PURPOSE

To evaluate the clinical efficacy of self-retained cryopreserved amniotic membrane in treating dry eye disease.

METHODS

Retrospective review of 10 patients treated with self-retained cryopreserved amniotic membrane (PROKERA® Slim [PKS], Bio-Tissue, Miami, FL) for moderate-to-severe dry eye refractory to conventional maximal medical treatments. Patients' symptoms, use of medications, conjunctival inflammation, corneal staining, and visual acuity were compared before and after treatment.

RESULTS

PKS was placed in 15 eyes of the 10 patients for 4.9 ± 1.5 days. All patients experienced symptomatic relief for a period of 4.2 ± 4.7 months (P<.001). Such improvement was accompanied by reduction of OSDI scores (P<.001), use of topical medications (P<.001), conjunctival hyperemia (P<.001), corneal staining (P<.001), and improvement of the visual acuity (P=.06). Linear regression analysis estimated that the optimal duration of PKS placement was 5 days to achieve an average symptom-free duration of 4 months in patients with dry eye. Surprisingly, PKS placement also generated improvement in the contralateral eyes.

CONCLUSION

This pilot study suggests that self-retained cryopreserved amniotic membrane via PKS can be used to treat moderate dry eye diseases and warrants further prospective controlled studies.

Different metabolic activity in placental and reflected regions of the human amniotic membrane

Cells of the human amniotic membrane (hAM) have stem cell characteristics with low immunogenicity and anti-inflammatory properties. While hAM is an excellent source for tissue engineering, so far, its sub-regions have not been taken into account. We show that placental and reflected hAM differ distinctly in morphology and functional activity, as the placental region has significantly higher mitochondrial activity, however significantly less reactive oxygen species. Since mitochondria may participate in processes such as cell rescue, we speculate that amniotic sub-regions may have different potential for tissue regeneration, which may be crucial for clinical applications.

Human epidermal neural crest stem cells as a source of Schwann cells

We show that highly pure populations of human Schwann cells can be derived rapidly and in a straightforward way, without the need for genetic manipulation, from human epidermal neural crest stem cells [hEPI-NCSC(s)] present in the bulge of hair follicles. These human Schwann cells promise to be a useful tool for cell-based therapies, disease modelling and drug discovery. Schwann cells are glia that support axons of peripheral nerves and are direct descendants of the embryonic neural crest. Peripheral nerves are damaged in various conditions, including through trauma or tumour-related surgery, and Schwann cells are required for their repair and regeneration. Schwann cells also promise to be useful for treating spinal cord injuries. Ex vivo expansion of hEPI-NCSC isolated from hair bulge explants, manipulating the WNT, sonic hedgehog and TGFβ signalling pathways, and exposure of the cells to pertinent growth factors led to the expression of the Schwann cell markers SOX10, KROX20 (EGR2), p75NTR (NGFR), MBP and S100B by day 4 in virtually all cells, and maturation was completed by 2 weeks of differentiation. Gene expression profiling demonstrated expression of transcripts for neurotrophic and angiogenic factors, as well as JUN, all of which are essential for nerve regeneration. Co-culture of hEPI-NCSC-derived human Schwann cells with rodent dorsal root ganglia showed interaction of the Schwann cells with axons, providing evidence of Schwann cell functionality. We conclude that hEPI-NCSCs are a biologically relevant source for generating large and highly pure populations of human Schwann cells.

Summary: Human epidermal neural crest stem cells isolated from the bulge of hair follicles are used to derive Schwann cells that could be useful for regenerative therapies, disease modelling and drug discovery.

Differentiation of human amniotic epithelial cells into Schwann‑like cells via indirect co‑culture with Schwann cells in vitro

Human amniotic epithelial cells (hAECs) exhibit multi‑lineage differentiation ability. The present study investigated the possibility that hAECs possess the potential to differentiate into Schwann‑like cells using an in vitro indirect co‑culture approach. hAECs were isolated via enzymatic digestion, and immunocytochemistry and flow cytometry were performed to identify the hAECs. The hAECs were co‑cultured with Schwann cells (SCs) to differentiate the hAECs into Schwann‑like cells via induced proximity. The expression of typical S‑100 SC markers in the co‑cultured hAECs was determined via immunocytochemistry. For the functional experiments, reverse transcription quantitative polymerase chain reaction (RT‑qPCR) was performed to measure the expression levels of nerve growth factor (NGF), brain‑derived neurotrophic factor (BDNF) and glial cell‑derived neurotrophic factor (GDNF) mRNA. In addition, neurite outgrowth was measured in PC12 cells following co‑culture with the differentiated hAECs. Subsequent to co‑culture with SCs for 21 days, the hAECs exhibited spindle‑like morphology. The immunocytochemistry results revealed that the co‑cultured hAECs expressed S‑100, indicating differentiation into Schwann‑like cells. RT‑qPCR revealed that NGF, BDNF and GDNF expression was upregulated upon differentiation. The average axon length of the PC12 cells increased from 21.32±5.45 to 51.32±8.56 µm subsequent to co‑culture with the differentiated hAECs. These results demonstrate that this indirect co‑culture microenvironment induced the hAECs to differentiate into Schwann‑like cells that exhibited the morphological, phenotypic and functional characteristics of SCs. Therefore, the use of differentiated hAECs that exhibit the characteristics of SCs provides a promising alternative to the present techniques used for peripheral nerve regeneration.