Characterization of laminin isoforms in human amnion

Laminin fragments conjugated with perlecan's growth factor-binding domain differentiate human induced pluripotent stem cells into skin-derived precursor cells

Deriving stem cells to regenerate full-thickness human skin is important for treating skin disorders without invasive surgical procedures. Our previous protocol to differentiate human induced pluripotent stem cells (iPSCs) into skin-derived precursor cells (SKPs) as a source of dermal stem cells employs mouse fibroblasts as feeder cells and is therefore unsuitable for clinical use. Herein, we report a feeder-free method for differentiating iPSCs into SKPs by customising culture substrates. We immunohistochemically screened for laminins expressed in dermal papillae (DP) and explored the conditions for inducing the differentiation of iPSCs into SKPs on recombinant laminin E8 (LM-E8) fragments with or without conjugation to domain I of perlecan (PDI), which binds to growth factors through heparan sulphate chains. Several LM-E8 fragments, including those of LM111, 121, 332, 421, 511, and 521, supported iPSC differentiation into SKPs without PDI conjugation. However, the SKP yield was significantly enhanced on PDI-conjugated LM-E8 fragments. SKPs induced on PDI-conjugated LM111-E8 fragments retained the gene expression patterns characteristic of SKPs, as well as the ability to differentiate into adipocytes, osteocytes, and Schwann cells. Thus, PDI-conjugated LM-E8 fragments are promising agents for inducing iPSC differentiation into SKPs in clinical settings.

Association of amnioinfusion volume at the time of surgery for twin-twin transfusion syndrome and latency to delivery

OBJECTIVE

To evaluate the impact of amnioinfusion and other peri-operative factors on pregnancy outcomes in the setting of Twin-twin transfusion syndrome (TTTS) treated via fetoscopic laser photocoagulation (FLP).

METHODS

Retrospective study of TTTS treated via FLP from 2010 to 2019. Pregnancies were grouped by amnioinfusion volume during FLP (<1 L vs. ≥1 L). The primary outcome was latency from surgery to delivery. An amnioinfusion statistic (AIstat) was created for each surgery based on the volume of fluid infused and removed and the preoperative deepest vertical pocket. Regression analysis was planned to assess the association of AIstat with latency.

RESULTS

Patients with amnioinfusion of ≥1 L at the time of FLP had decreased latency from surgery to delivery (61 ± 29.4 vs. 73 ± 28.8 days with amnioinfusion <1 L, p < 0.001) and increased preterm prelabor rupture of membranes (PPROM) <34 weeks (44.7% vs. 33.5%, p = 0.042). Amnioinfusion ≥1 L was associated with an increased risk of delivery <32 weeks (aRR 2.6, 95% CI 1.5-4.5), 30 weeks (aRR 2.4, 95% CI 1.5-3.8), and 28 weeks (aRR 1.9, 95% CI 1.1-2.3). Cox-proportional regression revealed that AIstat was inversely associated with latency (HR 1.1, 95% CI 1.1-1.2).

CONCLUSION

Amnioinfusion ≥1 L during FLP was associated with decreased latency after surgery and increased PPROM <34 weeks.

Placental Tissues as Biomaterials in Regenerative Medicine

Placental tissues encompass all the tissues which support fetal development, including the placenta, placental membrane, umbilical cord, and amniotic fluid. Since the 1990s there has been renewed interest in the use of these tissues as a raw material for regenerative medicine applications. Placental tissues have been extensively studied for their potential contribution to tissue repair applications. Studies have attributed their efficacy in augmenting the healing process to the extracellular matrix scaffolds rich in collagens, glycosaminoglycans, and proteoglycans, as well as the presence of cytokines within the tissues that have been shown to stimulate re-epithelialization, promote angiogenesis, and aid in the reduction of inflammation and scarring. The compositions and properties of all birth tissues give them the potential to be valuable biomaterials for the development of new regenerative therapies. Herein, the development and compositions of each of these tissues are reviewed, with focus on the structural and signaling components that are relevant to medical applications. This review also explores current configurations and recent innovations in the use of placental tissues as biomaterials in regenerative medicine.

Finding the Perfect Membrane: Current Knowledge on Barrier Membranes in Regenerative Procedures: A Descriptive Review

Guided tissue regeneration (GTR) and guided bone regeneration (GBR) became common procedures in the corrective phase of periodontal treatment. In order to obtain good quality tissue neo-formation, most techniques require the use of a membrane that will act as a barrier, having as a main purpose the blocking of cell invasion from the gingival epithelium and connective tissue into the newly formed bone structure. Different techniques and materials have been developed, aiming to obtain the perfect barrier membrane. The membranes can be divided according to the biodegradability of the base material into absorbable membranes and non-absorbable membranes. The use of absorbable membranes is extremely widespread due to their advantages, but in clinical situations of significant tissue loss, the use of non-absorbable membranes is often still preferred. This descriptive review presents a synthesis of the types of barrier membranes available and their characteristics, as well as future trends in the development of barrier membranes along with some allergological aspects of membrane use.

Finding the Perfect Membrane: Current Knowledge on Barrier Membranes in Regenerative Procedures: A Descriptive Review

Guided tissue regeneration (GTR) and guided bone regeneration (GBR) became common procedures in the corrective phase of periodontal treatment. In order to obtain good quality tissue neo-formation, most techniques require the use of a membrane that will act as a barrier, having as a main purpose the blocking of cell invasion from the gingival epithelium and connective tissue into the newly formed bone structure. Different techniques and materials have been developed, aiming to obtain the perfect barrier membrane. The membranes can be divided according to the biodegradability of the base material into absorbable membranes and non-absorbable membranes. The use of absorbable membranes is extremely widespread due to their advantages, but in clinical situations of significant tissue loss, the use of non-absorbable membranes is often still preferred. This descriptive review presents a synthesis of the types of barrier membranes available and their characteristics, as well as future trends in the development of barrier membranes along with some allergological aspects of membrane use.

Gene Expression in Amnion-Derived Cells Cultured on Recombinant Laminin 332-A Preliminary Study

Human amniotic cells (hAC) exhibit characteristics of undifferentiated cells and immunomodulatory properties. Recognition of the relationship between amniotic cells and components of the extracellular matrix is an important condition for their ex vivo preparation and further successful clinical application in regenerative medicine and transplantology. Laminin 332 (LN-332), as a natural component of the basement membrane of amniotic epithelial cells and a ligand for integrin receptors, may strongly influence the phenotype and fate of amniotic cells. We investigated the impact of recombinant LN-332 on hAC viability and expression of markers for pluripotency, early differentiation, adhesion, and immunomodulatory properties. During 14 days of culture, hAC were quantified and qualified by light microscopy, immunohistochemistry, immunocytochemistry, and flow cytometry. Gene expression was assessed with real-time polymerase chain reaction (RT-PCR) arrays and compared with differentiated cells originated from the three germ layers. LN-332 caused an over 2-fold increase in the total number of hAC, accompanied by a 75% reduction of SSEA-4-positive cells and an increase in HLA-ABC-positive cells. In particular, we observed that the presence of laminin 332 in the medium of a short-time culture modifies the effect of culture duration on hAC, enhancing time-dependent inhibition of expression of certain genes, including pluripotency and differentiation markers, laminin 332 subunits (which may be part of self-regulation of LN-332 synthesis by amniotic cells), and integrins. The changes observed in hAC were more distinct with respect to differentiated mesenchymal cells, resulting in more comparable phenotypes than those represented by differentiated endo- and ectodermal cells. We concluded that laminin 332 present in the culture medium influences to a certain extent proliferation, adhesion, and differentiation of amniotic cells in culture.

Human Amniotic Membrane: A Versatile Scaffold for Tissue Engineering

The human amniotic membrane (hAM) is a collagen-based extracellular matrix derived from the human placenta. It is a readily available, inexpensive, and naturally biocompatible material. Over the past decade, the development of tissue engineering and regenerative medicine, along with new decellularization protocols, has recast this simple biomaterial as a tunable matrix for cellularized tissue engineered constructs. Thanks to its biocompatibility, decellularized hAM is now commonly used in a broad range of medical fields. New preparation techniques and composite scaffold strategies have also emerged as ways to tune the properties of this scaffold. The current state of understanding about the hAM as a biomaterial is summarized in this review. We examine the processing techniques available for the hAM, addressing their effect on the mechanical properties, biodegradation, and cellular response of processed scaffolds. The latest in vitro applications, in vivo studies, clinical trials, and commercially available products based on the hAM are reported, organized by medical field. We also look at the possible alterations to the hAM to tune its properties, either through composite materials incorporating decellularized hAM, chemical cross-linking, or innovative layering and tissue preparation strategies. Overall, this review compiles the current literature about the myriad capabilities of the human amniotic membrane, providing a much-needed update on this biomaterial.

Human amnion epithelial cells expressing HLA-G as novel cell-based treatment for liver disease

Despite routine liver transplantation and supporting medical therapies, thousands of patients currently wait for an organ and there is an unmet need for more refined and widely available regenerative strategies to treat liver diseases. Cell transplants attempt to maximize the potential for repair and/or regeneration in liver and other organs. Over 40years of laboratory pre-clinical research and 25years of clinical procedures have shown that certain liver diseases can be treated by the infusion of isolated cells (hepatocyte transplant). However, like organ transplants, hepatocyte transplant suffers from a paucity of tissues useful for cell production. Alternative sources have been investigated, yet with limited success. The tumorigenic potential of pluripotent stem cells together with their primitive level of hepatic differentiation, have limited the use of stem cell populations. Stem cell sources from human placenta, and the amnion tissue in particular are receiving renewed interest in the field of regenerative medicine. Unlike pluripotent stem cells, human amnion epithelial (AE) cells are easily available without ethical or religious concerns; they do not express telomerase and are not immortal or tumorigenic when transplanted. In addition, AE cells have been reported to express genes normally expressed in mature liver, when transplanted into the liver. Moreover, because of the possibility of an immune-privileged status related to their expression of HLA-G, it might be possible to transplant human AE cells without immunosuppression of the recipient.

Amniotic membrane - A Novel material for the root coverage: A case series

Background:

Periodontal plastic surgical procedures aimed at coverage of exposed root surface. Owing to the second surgical donor site and difficulty in procuring a sufficient graft for the treatment of root coverage procedures, various alternative additive membranes have been used. A recent resorbable amniotic membrane, not only maintains the structural and anatomical configuration of regenerated tissues, but also enhances gingival wound healing, provides a rich source of stem cells. Therefore, amniotic membrane is choice of material these days in augmenting the better results in various periodontal procedures.

Aim:

The aim of this observational case series was to evaluate the effectiveness, predictability and the use of a novel material, amniotic membrane in the treatment of shallow-to-moderate isolated recession defects.

Materials and Methods:

A total of three cases, showing Miller's Class I or Class II gingival recession, participated in this study. Recession depth, recession width, keratinized gingiva (KG) tissue width, clinical attachment level (CAL) were recorded at baseline, 3 and 6 months postoperatively.

Results:

Six months following root coverage procedures, the mean root coverage was found to be 70.2 ± 6.8%. CAL significantly decreased from 6.4 ± 0.54 mm preoperatively to 3.5 ± 0.9 mm postoperatively at 6 months while KG showed significant improvement from 3.2 ± 0.28 mm preoperatively to 5.9 ± 0.74 mm postoperatively at 6 months.

Conclusion:

Autogenous graft tissue procurement significantly increases patient morbidity while also lengthening the duration of surgery in placing the graft, while self-adherent nature of amniotic membrane significantly reduces surgical time and made the procedure easier to perform, making it membrane of choice.

Amnion and Chorion Allografts in Combination with Coronally Advanced Flap in the Treatment of Gingival Recession: A Clinical Study

BACKGROUND

Guided tissue regeneration (GTR) based root coverage using different allograft membranes has been utilized to correct gingival recession defects with promising results. Amnion and chorion allograft membranes of alternative origin derived from human placental tissue has been advocated in the treatment of gingival recession. However, chorion membrane has been used in combination with amnion membrane no study has compared these allograft membranes in the treatment of gingival recession. Therefore, the purpose of this study was to clinically evaluate and compare the efficacy of amnion membrane and chorion membrane in combination with coronally advanced flap in the treatment of gingival recessions.

MATERIALS AND METHODS

Twelve systemically healthy patients having at least 2 bilateral Miller's Class I or Class II gingival recession were recruited and coronally advanced flap was performed with amnion membrane or chorion membrane. Clinical parameters such as gingival Index, plaque index, length of the recession, width of the recession, width of keratinized gingiva, relative attachment level were evaluated at baseline, 3 and 6 months post-surgery.

RESULTS

The mean decrease in length of recession (LR) for Chorion site was 2.00±1.54mm and amnion site was 1.58±1.14mm. The gain in attachment level for amnion site was 2.17±1.53mm and for chorion site was 1.58±1.22mm. The total mean percentage of root coverage was 34% for chorion site and 22% for amnion site.

CONCLUSION

Both amnion membrane and chorion membrane has shown to be versatile allograft material to be used in the treatment of root coverage.

Immunogenicity of decidual stromal cells in an epidermolysis bullosa patient and in allogeneic hematopoietic stem cell transplantation patients

Allogeneic mesenchymal stromal cells (MSCs) are widely used in regenerative medicine, but little is known about their immunogenicity. In this study, we monitored the therapeutic and immunogenic effects of decidual stromal cells (DSCs) from term placentas when used as a therapy for generalized severe junctional epidermolysis bullosa (JEB) (previously termed Herlitz JEB), a lethal condition caused by the lack of functional laminin-332. An 11-month-old JEB patient was treated with five infusions of allogeneic DSCs within a 3-month period. Amniotic membranes (AMs) were applied to severe wounds. After the treatment, wounds started to heal in the middle of the blisters, but the improvements were transient. After two infusions of DSCs, the JEB patient had developed multispecific anti-HLA class-I antibodies. No antibodies to laminin-332 were detected, but the patient had high levels of anti-bovine serum albumin antibodies, which could bind to DSCs. Peripheral blood mononuclear cells (PBMCs) from the patient had a higher proliferative response to DSCs than to third-party PBMCs, which contrasts with the pattern observed in healthy donors. Human DSCs and MSCs induced similar xenoreactivity in mice. Two of 16 allogeneic stem cell-transplanted patients, treated with DSCs for graft-versus-host disease or hemorrhagic cystitis, showed a positive flow cytometric crossmatch test. One patient had anti-HLA antibodies before DSC infusion, whereas the other had no anti-HLA antibodies at any time. AM and DSC infusions may have improved the healing process in the JEB patient, but DSCs appeared to induce anti-HLA antibodies. The risk of alloimmunization by DSCs seems to be low in immunocompromised patients.

Microenvironmental factors involved in human amnion mesenchymal stem cells fate decisions

Human amnion mesenchymal stem cells (HAMCs) show great differentiation and proliferation potential and also other remarkable features that could serve as an outstanding alternative source of stem cells in regenerative medicine. Recent reports have demonstrated various kinds of effective artificial niche that mimic the microenvironment of different types of stem cell to maintain and control their fate and function. The components of the stem cell microenvironment consist mainly of soluble and insoluble factors responsible for regulating stem cell differentiation and self-renewal. Extensive studies have been made on regulating HAMCs differentiation into specific phenotypes; however, the understanding of relevant factors in directing stem cell fate decisions in HAMCs remain underexplored. In this review, we have therefore identified soluble and insoluble factors, including mechanical stimuli and cues from the other supporting cells that are involved in directing HAMCs fate decisions. In order to strengthen the significance of understanding on the relevant factors involved in stem cell fate decisions, recent technologies developed to specifically mimic the microenvironments of specific cell lineages are also reviewed. Copyright © 2015 John Wiley & Sons, Ltd.

Guided tissue regeneration in endodontic surgery by using a bioactive resorbable membrane

INTRODUCTION

Guided tissue regeneration is a valuable technique available to the endodontist because the quality, quantity, or extent of bone loss cannot be visualized by the surgeon until the tissue is reflected and the surgical site is exposed.

METHODS

After repeated attempts at nonsurgical treatment, a patient with a recurring sinus tract over the distobuccal root of an upper molar ultimately had the distobuccal root resected, leaving a 10 × 10 mm bony defect. This dehiscence was filled with freeze-dried bone and covered with a flexible and absorbable bioactive membrane that was new to endodontics.

RESULTS

Healing was uneventful, and bone regeneration was rapid and extensive as observed at the time of a second surgery just 5 months later. This can be attributed at least in part to the use of the bioactive membrane that contains an array of growth factors that enhance cell proliferation, inflammation, recruitment of progenitor cells, and metalloproteinase activity.

CONCLUSIONS

The use of the bioactive membrane in endodontic surgery should be considered to best restore the attachment apparatus to the tooth and prevent the downgrowth of a long junctional epithelium. The endodontist's attention must not be limited to the apical region alone.

Amniotic membrane properties and current practice of amniotic membrane use in ophthalmology in Slovenia

Amniotic membrane (AM) is the innermost, multilayered part of the placenta. When harvested, processed and stored properly, its properties, stemming from AM biological composition, make it a useful tissue for ophthalmic surgery. AM was shown to have several beneficial effects: it promotes epithelization, has antimicrobial effects, decreases inflammation, fibrosis and neovascularization. Many case reports and case series as well as practical experience (e.g. reconstruction of conjunctival and corneal defects, treatment of corneal ulcers) demonstrated the beneficial effect of AM for different ophthalmological indications. The combination of the above mentioned beneficial effects and reasonable mechanical properties are also the reason why AM is used as a substrate for ex vivo expansion of epithelial progenitor cells. Recently, amnion-derived cells, which also have stem cell characteristics, have been proposed as potential contributors to cell-based treatment of ocular surface disease. However, the use of AM remains one of the least standardized methods in ophthalmic surgery. In this review, the various properties of AM and its current clinical use in ophthalmology in Slovenia are discussed.

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

Human amniotic membrane (hAM) is a tissue containing cells with proven stem cell properties. In its decellularized form it has been successfully applied as nerve conduit biomaterial to improve peripheral nerve regeneration in injury models. We hypothesize that viable hAM without prior cell isolation can be differentiated towards the Schwann cell lineage to generate a possible alternative to commonly applied tissue engineering materials for nerve regeneration. For in vitro Schwann cell differentiation, biopsies of hAM of 8 mm diameter were incubated with a sequential order of neuronal induction and growth factors for 21 days and characterized for cellular viability and the typical glial markers glial fibrillary acidic protein (GFAP), S100β, p75 and neurotrophic tyrosine kinase receptor (NTRK) using immunohistology. The secretion of the neurotrophic factors brain-derived neurotrophic factor (BDNF) and glial cell-derived neurotrophic factor (GDNF) was quantified by ELISA. The hAM maintained high viability, especially under differentiation conditions (90.2 % ± 41.6 day 14; 80.0 % ± 44.5 day 21 compared to day 0). Both, BDNF and GDNF secretion was up-regulated upon differentiation. The fresh membrane stained positive for GFAP and p75 and NTRK, which was strongly increased after culture in differentiation conditions. Especially the epithelial layer within the membrane exhibited a change in morphology upon differentiation forming a multi-layered epithelium with intense accumulations of the marker proteins. However, S100β was expressed at equal levels and equal distribution in fresh and cultured hAM conditions. Viable hAM may be a promising alternative to present formulations used for peripheral nerve regeneration.

Amniotic membrane in oral and maxillofacial surgery

PURPOSE

Following its renaissance in ophthalmology during the 1990s, preserved human amniotic membrane (HAM) has become an attractive biomaterial for all surgical disciplines. This article reviews the current and potential use of HAM in oral and maxillofacial surgery, its postulated properties and common preservation techniques.

METHODS

Literature was identified by an electronic search of PubMed in July 2012; this was supplemented from the reference lists of the consulted papers.

RESULTS

HAM has been used in the field of oral and maxillofacial surgery from 1969 onwards because of its immunological preference and its pain-reducing, antimicrobial, mechanical and side-dependent adhesive or anti-adhesive properties. The effects of HAM on dermal and mucosal re-epithelialisation have been highlighted. Typically, HAM is applied after being banked in a glycerol-preserved, DMSO-preserved or freeze-dried and irradiated state. Whereas the use of HAM in flap surgery and in intra-oral and extra-oral lining is reported frequently, novel HAM applications in post-traumatic orbital surgery and temporomandibular joint surgery have been added since 2010. Tissue engineering with HAM is a fast-expanding field with a high variety of future options.

CONCLUSIONS

Preserved HAM is considered to be a safe and sufficient biomaterial in all fields of oral and maxillofacial wound healing. Recently published novel indications for HAM application lack a high level of evidence and need to be studied further.

Amniotic fluid and amniotic membrane stem cells: marker discovery

Amniotic fluid (AF) and amniotic membrane (AM) have been recently characterized as promising sources of stem or progenitor cells. Both not only contain subpopulations with stem cell characteristics resembling to adult stem cells, such as mesenchymal stem cells, but also exhibit some embryonic stem cell properties like (i) expression of pluripotency markers, (ii) high expansion in vitro, or (iii) multilineage differentiation capacity. Recent efforts have been focused on the isolation and the detailed characterization of these stem cell types. However, variations in their phenotype, their heterogeneity described by different groups, and the absence of a single marker expressed only in these cells may prevent the isolation of a pure homogeneous stem cell population from these sources and their potential use of these cells in therapeutic applications. In this paper, we aim to summarize the recent progress in marker discovery for stem cells derived from fetal sources such as AF and AM, using novel methodologies based on transcriptomics, proteomics, or secretome analyses.

Potential antitumor therapeutic strategies of human amniotic membrane and amniotic fluid-derived stem cells

As stem cells are capable of self-renewal and can generate differentiated progenies for organ development, they are considered as potential source for regenerative medicine and tissue replacement after injury or disease. Along with this capacity, stem cells have the therapeutic potential for treating human diseases including cancers. According to the origins, stem cells are broadly classified into two types: embryonic stem cells (ESCs) and adult stem cells. In terms of differentiation potential, ESCs are pluripotent and adult stem cells are multipotent. Amnion, which is a membranous sac that contains the fetus and amniotic fluid and functions in protecting the developing embryo during gestation, is another stem cell source. Amnion-derived stem cells are classified as human amniotic membrane-derived epithelial stem cells, human amniotic membrane-derived mesenchymal stem cells and human amniotic fluid-derived stem cells. They are in an intermediate stage between pluripotent ESCs and lineage-restricted adult stem cells, non-tumorigenic, and contribute to low immunogenicity and anti-inflammation. Furthermore, they are easily available and do not cause any controversial issues in their recovery and applications. Not only are amnion-derived stem cells applicable in regenerative medicine, they have anticancer capacity. In non-engineered stem cells transplantation strategies, amnion-derived stem cells effectively target the tumor and suppressed the tumor growth by expressing cytotoxic cytokines. Additionally, they also have a potential as novel delivery vehicles transferring therapeutic genes to the cancer formation sites in gene-directed enzyme/prodrug combination therapy. Owing to their own advantageous properties, amnion-derived stem cells are emerging as a new candidate in anticancer therapy.

Amniotic membrane: from structure and functions to clinical applications

Amniotic membrane (AM) or amnion is a thin membrane on the inner side of the fetal placenta; it completely surrounds the embryo and delimits the amniotic cavity, which is filled by amniotic liquid. In recent years, the structure and function of the amnion have been investigated, particularly the pluripotent properties of AM cells, which are an attractive source for tissue transplantation. AM has anti-inflammatory, anti-bacterial, anti-viral and immunological characteristics, as well as anti-angiogenic and pro-apoptotic features. AM is a promoter of epithelialization and is a non-tumorigenic tissue and its use has no ethical problems. Because of its attractive properties, AM has been applied in several surgical procedures related to ocular surface reconstruction and the genito-urinary tract, skin, head and neck, among others. So far, the best known and most auspicious applications of AM are ocular surface reconstruction, skin applications and tissue engineering. However, AM can also be applied in oncology. In this area, AM can prevent the delivery of nutrients and oxygen to cancer cells and consequently interfere with tumour angiogenesis, growth and metastasis.