The Long Path of Human Placenta, and Its Derivatives, in Regenerative Medicine

Plasticity of bone marrow-derived cell differentiation depending on microenvironments in the skin

Bone marrow-derived cells (BMDCs) are heterogeneous populations in which not only pluripotent stem cells, namely, hematopoietic stem cells (HSCs), mesenchymal stem cells (MSC) but also endothelial progenitor cells (EPC) are involved. BMDCs contribute to the maintenance of homeostasis and recovery from disrupted homeostasis as the immune, endocrine, and nervous systems. The skin is the largest organ in which various tissues, such as the epidermis, dermis, skin appendages (i.e., hair follicles), fats, muscles, and vessels, are tightly and systematically packed. It functions as a physical barrier to block the invasion of harmful substances and pathogenic microorganisms and properly regulate water evaporation. The skin is exposed to injuries from external stimuli because it is the outermost layer and owing to its specificity. Recovery from physical injuries and DNA mutations occurs constantly in the skin, but medical treatments are required for impaired wound healing. Recently, conservative treatments utilizing scaffolds have attracted attention as alternatives to surgical therapy, which is highly invasive. Against this background, numerous scaffolds are available in a clinical setting, although they have not surpassed surgery because of their distinct disadvantages. Here, we discuss the plasticity of BMDCs in the skin to maintain homeostasis, in addition to their critical roles on recovery from disrupted homeostasis. We also share our perspective on how scaffolds can be developed to establish scaffolds beyond surgery to regenerate skin structure during wound healing by maximally utilizing the plasticity of BMDCs.

Comparative Effectiveness of Placental Allografts in the Treatment of Diabetic Lower Extremity Ulcers and Venous Leg Ulcers in U.S. Medicare Beneficiaries: A Retrospective Observational Cohort Study Using Real-World Evidence

Objective: To compare the effectiveness of cellular tissue products (CTP) versus standard care in U.S. Medicare beneficiaries with diabetic lower extremity ulcers (DLEUs) or venous leg ulcers (VLUs). Approach: We performed a retrospective cohort study using real-world evidence from U.S. Medicare claims for DLEUs or VLUs between 2016 and 2020. There were three cohorts evaluated: viable cryopreserved placental membrane (vCPM) or viable lyopreserved placental membrane (vLPM); other CTP; and standard care. Claims were collapsed into episodes of care. Univariate and bivariate statistics were used to examine the frequency distribution of demographics and clinical variables. Multivariable zero-inflated binomial regressions were used to evaluate mortality and recurrence trends. Logistic regression compared three adverse outcomes (AOs): amputation; 1-year mortality; and wound recurrence. Results: There were 333,362 DLEU episodes among 261,101 beneficiaries, and 122,012 VLU episodes among 80,415 beneficiaries. DLEU treatment with vLPM was associated with reduced 1-year mortality (-26%), reduced recurrence (-91%), and reduced AOs (-71%). VLU treatment with vCPM or vLPM was associated with reduced 1-year mortality (-23%), reduced recurrence (-80%), and 66.77% reduction in AOs. These allografts were also associated with a 49% and 73% reduced risk of recurrence in DLEU and VLU, respectively, compared with other CTPs. Finally, vCPM or vLPM were associated with noninferior prevention of AOs related to amputation, mortality, and recurrence (95% CI: 0.69-1.14). Conclusions: DLEUs and VLUs treated with vCPM and vLPM allografts are associated with lowered 1-year mortality, wound recurrence, and AOs in DLEUs and VLUs compared with standard care. Decision makers weighing coverage of placental allografts should consider these added short- and long-term clinical benefits relative to costly management and high mortality of Medicare's most frequent wounds.

Processing methods for human amniotic membrane as scaffold for tissue engineering with mesenchymal stromal human cells

Tissue engineering is an interdisciplinary field that applies the principles of engineering and life sciences toward the development of biological substitutes that restore, maintain, or improve tissue function. The aims of this work were to compare chemically and physically processed human Amniotic Membranes (hAM) and analyze the cytocompatibility and proliferation rate (PR) of two primary human mesenchymal stromal cell lines, from different sources and donor conditions seeded over these scaffolds. The evaluated hAM processes were: cold shock to obtain a frozen amniotic membrane (FEAM) with remaining dead epithelial cells, denudation of hAM with trypsin for 20/10 min (DEAM20/10) or treatment with sodium dodecyl sulfate to decellularized hAM (DAM). All samples were sterilized with gamma radiation. The selection of the treated hAM to then generate composites was performed by scanning and transmission electron microscopy and characterization by X-ray diffraction, selecting DEAM10 and FEAM as scaffolds for cell seeding. Two sources of primary human stromal cells were used, both developed by our researchers, human Dental Pulp Stem Cells (hDPSC) from living donors and human Mesenchymal Stromal Cells (hMSC) from bone marrow isolated from brain dead donors. This last line of cells conveys a novel source of human cells that, to our knowledge, have not been tested as part of this type of construct. We developed four in vitro constructs without cytotoxicity signs and with different PR depending on the scaffolds and cells. hDPSC and hMSC grew over both FEAM and DEAM10, but DEAM10 allowed higher PR.

Amnion-derived hydrogels as a versatile platform for regenerative therapy: from lab to market

In recent years, the amnion (AM) has emerged as a versatile tool for stimulating tissue regeneration and has been of immense interest for clinical applications. AM is an abundant and cost-effective tissue source that does not face strict ethical issues for biomedical applications. The outstanding biological attributes of AM, including side-dependent angiogenesis, low immunogenicity, anti-inflammatory, anti-fibrotic, and antibacterial properties facilitate its usage for tissue engineering and regenerative medicine. However, the clinical usage of thin AM sheets is accompanied by some limitations, such as handling without folding or tearing and the necessity for sutures to keep the material over the wound, which requires additional considerations. Therefore, processing the decellularized AM (dAM) tissue into a temperature-sensitive hydrogel has expanded its processability and applicability as an injectable hydrogel for minimally invasive therapies and a source of bioink for the fabrication of biomimetic tissue constructs by recapitulating desired biochemical cues or pre-defined architectural design. This article reviews the multi-functionality of dAM hydrogels for various biomedical applications, including skin repair, heart treatment, cartilage regeneration, endometrium regeneration, vascular graft, dental pulp regeneration, and cell culture/carrier platform. Not only recent and cutting-edge research is reviewed but also available commercial products are introduced and their main features and shortcomings are elaborated. Besides the great potential of AM-derived hydrogels for regenerative therapy, intensive interdisciplinary studies are still required to modify their mechanical and biological properties in order to broaden their therapeutic benefits and biomedical applications. Employing additive manufacturing techniques (e.g., bioprinting), nanotechnology approaches (e.g., inclusion of various bioactive nanoparticles), and biochemical alterations (e.g., modification of dAM matrix with photo-sensitive molecules) are of particular interest. This review article aims to discuss the current function of dAM hydrogels for the repair of target tissues and identifies innovative methods for broadening their potential applications for nanomedicine and healthcare.

Graphene oxide accelerates TGFβ-mediated epithelial-mesenchymal transition and stimulates pro-inflammatory immune response in amniotic epithelial cells

The application of biomaterials on immune regenerative strategies to deal with unsolved pathologies is getting attention in the field of tissue engineering. In this context, graphene oxide (GO) has been proposed as an immune-mimetic material largely used for developing stem cell-based regenerative therapies, since it has shown to influence stem cell behavior and modulate their immune response. Similarly, amniotic epithelial stem cells (AECs) are getting an increasing clinical interest as source of stem cells due to their great plasticity and immunomodulatory paracrine activities, even though GO bio-mimetic effects still remain unknown. To this aim, GO-functionalized glass coverslips have been used for AECs culture. The results demonstrated how GO-coating is able to induce and accelerate the Epithelial-Mesenchymal Transition (EMT), in a process mediated by the intracellular activation of TGFβ1-SMAD2/3 signaling pathway. The trans-differentiation towards mesenchymal phenotype provides AECs of migratory ability and substantially changes the pattern of cytokines secretion upon inflammatory stimulus. Indeed, GO-exposed AECs enhance their pro-inflammatory interleukins production thus inducing a more efficient activation of macrophages and, at the same time, by slightly reducing their inhibitory action on peripheral blood mononuclear cells proliferation. Therefore, the adhesion of AECs on GO-functionalized surfaces might contribute to the generation of a tailored microenvironment useful to face both the phases of the inflammation, thereby fostering the regenerative process.

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.

Immunomodulatory amnion-derived mesenchymal stromal cells preserve muscle function in a mouse model of Duchenne muscular dystrophy

BACKGROUND

Duchenne muscular dystrophy (DMD) is an incurable genetic disease characterized by degeneration and necrosis of myofibers, chronic inflammation, and progressive muscle weakness resulting in premature mortality. Immunosuppressive multipotent mesenchymal stromal cell (MSC) therapy could be an option for DMD patients. We focused on amnion-derived mesenchymal stromal cells (AMSCs), a clinically viable cell source owing to their unique characteristics, such as non-invasive isolation, mitotic stability, ethical acceptability, and minimal risk of immune reaction and cancer. We aimed to identify novel immunomodulatory effects of AMSCs on macrophage polarization and their transplantation strategies for the functional recovery of skeletal and cardiac muscles.

METHODS

We used flow cytometry to analyze the expression of anti-inflammatory M2 macrophage markers on peripheral blood mononuclear cells (PBMCs) co-cultured with human AMSCs (hAMSCs). hAMSCs were intravenously injected into DMD model mice (mdx mice) to assess the safety and efficacy of therapeutic interventions. hAMSC-treated and untreated mdx mice were monitored using blood tests, histological examinations, spontaneous wheel-running activities, grip strength, and echocardiography.

RESULTS

hAMSCs induced M2 macrophage polarization in PBMCs via prostaglandin E₂ production. After repeated systemic hAMSC injections, mdx mice exhibited a transient downregulation of serum creatin kinase. Limited mononuclear cell infiltration and a decreased number of centrally nucleated fibers were indicative of regenerated myofibers following degeneration, suggesting an improved histological appearance of the skeletal muscle of hAMSC-treated mdx mice. Upregulated M2 macrophages and altered cytokine/chemokine expressions were observed in the muscles of hAMSC-treated mdx mice. During long-term experiments, a significant decrease in the grip strength in control mdx mice significantly improved in the hAMSC-treated mdx mice. hAMSC-treated mdx mice maintained running activity and enhanced daily running distance. Notably, the treated mice could run longer distances per minute, indicating high running endurance. Left ventricular function in DMD mice improved in hAMSC-treated mdx mice.

CONCLUSIONS

Early systemic hAMSC administration in mdx mice ameliorated progressive phenotypes, including pathological inflammation and motor dysfunction, resulting in the long-term improvement of skeletal and cardiac muscle function. The therapeutic effects might be associated with the immunosuppressive properties of hAMSCs via M2 macrophage polarization. This treatment strategy could provide therapeutic benefits to DMD patients.

Treatment of Gingival Recession Defects with Pouch and Tunnel Technique Using Connective Tissue Graft and Lyophilized Chorion Membrane in Smokers

BACKGROUND The chorion membrane has been used for several decades as an allograft in tissue repair and various periodontal regenerative procedures. The present study, conducted at a single center in India, aimed to evaluate and compare the clinical outcomes of 26 gingival recession sites in chronic smokers treated using a pouch and tunnel technique with connective tissue graft (CTG) and lyophilized chorion membrane (LCM). MATERIAL AND METHODS The study included 22 smokers with 26 sites of recession defect, with Miller's class I and class II gingival recession, which were allotted into control and test groups. The control group (13 sites) was treated with CTG, and the test group (13 sites) was treated with LCM. Clinical parameters like recession depth, recession width, relative clinical attachment level (RCAL), relative gingival position, width of attached gingiva, and width of keratinized gingiva were recorded at baseline and 6 months postoperatively. Visual analogue scores for pain and wound-healing index scores were assessed in the first week after surgery. RESULTS All clinical parameters showed significant improvements from baseline to 6 months postoperatively in the control and test groups. Recession width, RCAL, width of attached gingiva, and width of keratinized gingiva demonstrated significant differences, whereas mean root coverage percentage and recession depth did not show any significant differences between the study groups at 6 months postoperatively. CONCLUSIONS This study supports the role of LCM allograft as a scaffold to promote soft tissue regeneration and has demonstrated a favorable role for its use in root coverage procedures in patients who smoke.

Acellular Human Placenta Small-Diameter Vessels as a Favorable Source of Super-Microsurgical Vascular Replacements: A Proof of Concept

In this study, we aimed to evaluate the human placenta as a source of blood vessels that can be harvested for vascular graft fabrication in the submillimeter range. Our approach included graft modification to prevent thrombotic events. Submillimeter arterial grafts harvested from the human placenta were decellularized and chemically crosslinked to heparin. Graft performance was evaluated using a microsurgical arteriovenous loop (AVL) model in Lewis rats. Specimens were evaluated through hematoxylin-eosin and CD31 staining of histological sections to analyze host cell immigration and vascular remodeling. Graft patency was determined 3 weeks after implantation using a vascular patency test, histology, and micro-computed tomography. A total of 14 human placenta submillimeter vessel grafts were successfully decellularized and implanted into AVLs in rats. An appropriate inner diameter to graft length ratio of 0.81 ± 0.16 mm to 7.72 ± 3.20 mm was achieved in all animals. Grafts were left in situ for a mean of 24 ± 4 days. Decellularized human placental grafts had an overall patency rate of 71% and elicited no apparent immunological responses. Histological staining revealed host cell immigration into the graft and re-endothelialization of the vessel luminal surface. This study demonstrates that decellularized vascular grafts from the human placenta have the potential to serve as super-microsurgical vascular replacements.

Reporting Criteria for Clinical Trials on Medication-Related Osteonecrosis of the Jaw (MRONJ): A Review and Recommendations

Medication-related osteonecrosis of the jaw (MRONJ) is a complication caused by anti-resorptive agents and anti-angiogenesis drugs. Since we wanted to write a protocol for a randomized clinical trial (RCT), we reviewed the literature for the essential information needed to estimate the size of the active patient population and measure the effects of therapeutics. At the same time, we designed a questionnaire intended for clinicians to collect detailed information about their practices. Twelve essential criteria and seven additional items were identified and compiled from 43 selected articles. Some of these criteria were incorporated in the questionnaire coupled with data on clinical practices. Our review found extensive missing data and a lack of consensus. For example, the success rate often combined MRONJ stages, diseases, and drug treatments. The occurrence date and evaluation methods were not harmonized or quantitative enough. The primary and secondary endpoints, failure definition, and date coupled to bone measurements were not well established. This information is critical for writing a RCT protocol. With this review article, we aim to encourage authors to contribute all their findings in the field to bridge the current knowledge gap and provide a stronger database for the coming years.

Organoids and Their Research Progress in Plastic and Reconstructive Surgery

Organoids are 3D structures generated from stem cells. Their functions and physiological characteristics are similar to those of normal organs. They are used in disease mechanism research, new drug development, organ transplantation and other fields. In recent years, the application of 3D materials in plastic surgery for repairing injuries, filling, tissue reconstruction and regeneration has also been investigated. The PubMed/MEDLINE database was queried to search for animal and human studies published through July of 2022 with search terms related to Organoids, Plastic Surgery, Pluripotent Stem Cells, Bioscaffold, Skin Reconstruction, Bone and Cartilage Regeneration. This review presents stem cells, scaffold materials and methods for the construction of organoids for plastic surgery, and it summarizes their research progress in plastic surgery in recent years.Level of Evidence III This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Porcine placental extract increase the cellular NAD levels in human epidermal keratinocytes

Nicotinamide adenine dinucleotide (NAD) is an essential cofactor for numerous enzymes involved in energy metabolism. Because decreasing NAD levels is a common hallmark of the aging process in various tissues and organs, maintaining NAD levels has recently been of interest for the prevention of aging and age-related diseases. Although placental extract (PE) are known to possess several anti-aging effects, the NAD-boosting activity of PE remains unknown. In this study, we found that porcine PE (PPE) significantly increased intracellular NAD levels in normal human epidermal keratinocytes (NHEKs). PPE also attenuated the NAD depletion induced by FK866, an inhibitor of nicotinamide phosphoribosyltransferase (NAMPT). Interestingly, only the fraction containing nicotinamide mononucleotide (NMN), nicotinamide riboside (NR), and nicotinamide (NAM) restored NAD content in NHEKs in the absence of NAMPT activity. These results suggest that PPE increases intracellular NAD by providing NAD precursors such as NMN, NR, and NAM. Finally, we showed that the application of PPE to the stratum corneum of the reconstructed human epidermis significantly ameliorated FK866-induced NAD depletion, suggesting that topical PPE may be helpful for increasing skin NAD levels. This is the first study to report the novel biological activity of PE as an NAD booster in human epidermal cells.

Evaluation of Antiaging Effect of Sheep Placenta Extract Using SAMP8 Mice

Widely used in traditional medicine, sheep placenta extract (SPE) is known for its physiological effects such as wound healing, antioxidant, and anti-inflammatory properties. However, the effect of SPE on antiaging is still unclear. In this study, we investigated the effect of SPE on aging through the senescence-accelerated mouse prone 8 (SAMP8) strain. We designed an experiment using both male and female mice randomly divided into 4 groups (n = 10) as follows: Group A—control group; Group B—low-dose SPE (61.5 mg/kg BW/day); Group C—medium-dose SPE (123 mg/kg BW/day); and Group D—high-dose SPE (184.5 mg/kg BW/day). As a result of measuring the aging index parameters such as skin glossiness, spine lordosis, and kyphosis, it was found that the treatment of SPE lowered the aging index. In addition, we found that biochemical parameters such as lactic acid, glucose, ketone bodies, free fatty acids, tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6) were not changed in the experimental group treated with SPE for 13 weeks. Finally, we found that lipid peroxidation (LPO) was decreased, while the activities of catalase and superoxide dismutase (SOD) were significantly increased in the brain tissues of SPE-treated male and female mice. Supplementation of SPE lowered the oxidative stress caused by the aging process in mice without toxicity and decreased the aging index, suggesting the value of SPE as an effective antiaging treatment.

Perinatal derivatives application: Identifying possibilities for clinical use

Perinatal derivatives are drawing growing interest among the scientific community as an unrestricted source of multipotent stromal cells, stem cells, cellular soluble mediators, and biological matrices. They are useful for the treatment of diseases that currently have limited or no effective therapeutic options by means of developing regenerative approaches. In this paper, to generate a complete view of the state of the art, a comprehensive 10-years compilation of clinical-trial data with the common denominator of PnD usage has been discussed, including commercialized products. A set of criteria was delineated to challenge the 10-years compilation of clinical trials data. We focused our attention on several aspects including, but not limited to, treated disorders, minimal or substantial manipulation, route of administration, dosage, and frequency of application. Interestingly, a clear correlation of PnD products was observed within conditions, way of administration or dosage, suggesting there is a consolidated clinical practice approach for the use of PnD in medicine. No regulatory aspects could be read from the database since this information is not mandatory for registration. The database will be publicly available for consultation. In summary, the main aims of this position paper are to show possibilities for clinical application of PnD and propose an approach for clinical trial preparation and registration in a uniform and standardized way. For this purpose, a questionnaire was created compiling different sections that are relevant when starting a new clinical trial using PnD. More importantly, we want to bring the attention of the medical community to the perinatal products as a consolidated and efficient alternative for their use as a new standard of care in the clinical practice.

Questions about Residual Cell Viability in Cryopreserved Human Amniotic Membrane and Its Impact on Clinical Applications

We questioned the relevance of evaluating residual cell viability in human amniotic membrane (hAM) after its cryopreservation since cell survival is controversial and its ability to act as a matrix (including the presence of growth factors and cytokines) appears to be most important for tissue regeneration purposes. We also discussed the usefulness of osteodifferentiating amniotic cells in whole hAM for bone repair applications. We have evidence that determining residual cell viability after cryopreservation and hAM osteodifferentiation is not justified.

Human PMSCs-derived small extracellular vesicles alleviate neuropathic pain through miR-26a-5p/Wnt5a in SNI mice model

BACKGROUND

Mesenchymal stem cell (MSCs)-derived small Extracellular Vesicles (sEVs) are considered as a new cell-free therapy for pain caused by nerve injury, but whether human placental mesenchymal stem cell-derived sEVs relieve pain in sciatic nerve injury and its possible mechanism are still unclear. In this study, we investigated the roles of hPMSCs-derived sEVs and related mechanisms in neuropathic pain.

METHODS

The spared nerve injury (SNI) mouse model was employed. Intrathecal injection of sEVs or miR-26a-5p agomir was performed on the seventh day of modeling, to study its anti-nociceptive effect. sEVs' miRNA sequencing (miRNA-Seq) and bioinformatics analysis were performed to study the downstream mechanisms of miRNAs. RT-qPCR, protein assay and immunofluorescence were used for further validation.

RESULTS

A single intrathecal injection of sEVs durably reversed mechanical hypersensitivity in the left hind paw of mice with partial sciatic nerve ligation. Immunofluorescence studies found that PKH26-labeled sEVs were visible in neurons and microglia in the dorsal horn of the ipsilateral L4/5 spinal cord and more enriched in the ipsilateral. According to miRNA-seq results, we found that intrathecal injection of miR-26a-5p agomir, the second high counts microRNA in hPMSCs derived sEVs, significantly suppressed neuropathic pain and neuroinflammation in SNI mice. Bioinformatics analysis and dual-luciferase reporter gene analysis identified Wnt5a as a direct downstream target gene of miR-26a-5p. The results showed that overexpression of miR-26a-5p in vivo could significantly reduce the expression level of Wnt5a. In addition, Foxy5, a mimetic peptide of Wnt5a, can significantly reverse the inhibitory effect of miR-26a-5p on neuroinflammation and neuropathic pain, and at the same time, miR-26a-5p can rescue the effect of Foxy5 by overexpression.

CONCLUSIONS

We reported that hPMSCs derived sEVs as a promising therapy for nerve injury induced neuropathic pain. In addition, we showed that the miR-26a-5p in the sEVs regulated Wnt5a/Ryk/CaMKII/NFAT partly take part in the analgesia through anti-neuroinflammation, which suggests an alleviating pain effect through non-canonical Wnt signaling pathway in neuropathic pain model in vivo.

Role of Placental Extracts in Periodontal Regeneration: A Literature Review

Periodontium is a specialized tissue surrounding the teeth. It is made up of the gingiva, periodontal ligament, cementum, and alveolar bone. The healing of periodontal tissues when infected occurs through repair and regeneration. The central dogma of regenerative periodontics is to stimulate a cascade of healing events that, if coordinated well, can lead to proper tissue synthesis which in turn would play a very important part in managing periodontitis and preventing tooth loss.

Many regenerative procedures are being followed in periodontics using newer and modified barrier membranes. Placental membranes like amnion, chorion and amnion-chorion membranes are one among these that serve the purpose because of their active components and therapeutic effects. This literature review highlights the benefits of placental extracts in regenerative periodontal therapy.

A Canadian Survey of Patients' Attitudes Toward Donation of Products of Conception for Research at the Time of Their Aspiration Abortion

OBJECTIVE

We explored patients' attitudes toward donating products of conception for research at the time of their aspiration abortion.

STUDY DESIGN

We surveyed patients presenting for first or second trimester aspiration abortion to the abortion service at British Columbia Women's Hospital over a six-month period in 2018. Questions explored demographics, attitudes toward tissue donation, willingness to donate products of conception for research, and how the option of donating tissue influenced patients' perception of their abortion. We analyzed quantitative data using descriptive statistics and answers to open-ended questions using content analysis.

RESULTS

The partially tracked response rate to our survey was n=35 of 46 (76%). Of 98 respondents included for analysis 77 (79%) were willing to donate their products of conception to research. Most respondents (n=85, 93%), 49 (54%) of whom had ever been offered to actually donate tissue, reported that tissue donation would either positively change (n=33, 36%) or not change (n=52, 57%) how they felt at the time of their abortion. The majority of respondents (n=25, 60%) who were not invited to donate their products of conception would have liked the opportunity to do so. Content analysis of open-ended responses from those willing to donate identified the categories of helping others, contributing to research and providing meaning beyond the respondents' individual experience.

CONCLUSIONS

Patients' willingness to donate products of conception to research and their associated positive attitudes provide important support for researchers and clinicians who are involved in research that uses products of conception.

IMPLICATIONS

Our data may inform research programs and abortion clinics involved in research using products of conception by better understanding the patient experience of being involved in this type of research.

Plumping up a Cushion of Human Biowaste in Regenerative Medicine: Novel Insights into a State-of-the-Art Reserve Arsenal

Major breakthroughs and disruptive methods in disease treatment today owe their thanks to our inch by inch developing conception of the infinitive aspects of medicine since the very beginning, among which, the role of the regenerative medicine can on no account be denied, a branch of medicine dedicated to either repairing or replacing the injured or diseased cells, organs, and tissues. A novel means to accomplish such a quest is what is being called “medical biowaste”, a large assortment of biological samples produced during a surgery session or as a result of physiological conditions and biological activities. The current paper accentuating several of a number of promising sources of biowaste together with their plausible applications in routine clinical practices and the confronting challenges aims at inspiring research on the existing gap between clinical and basic science to further extend our knowledge and understanding concerning the potential applications of medical biowaste.

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.

Amniotic growth factors enhanced human pre-adipocyte cell viability and differentiation under hypoxia

One of the major drawbacks associated with autologous fat grafting is unpredictable graft retention. Various efforts to improve the survivability of these cells have been explored, but these methods are time‐consuming, complex, and demand significant technical skill. In our study, we examine the use of cryopreserved amniotic membrane as a source of exogenous growth factors to improve adipocyte survivability under normal and hypoxic conditions. Human primary preadipocytes were cultured in a gelatin‐ferulic acid (Gtn‐FA) hydrogel with variable oxygen concentration and treated with amniotic membrane‐derived condition medium (CM) for 7 days. This hydrogel provides a hypoxic environment and also creates a 3D cell culture to better mimic recipient site conditions. The O₂ concentration in the hydrogel was measured by electron paramagnetic resonance oxygen imaging (EPROI). The conjugation of FA was confirmed by FTIR and NMR spectroscopy. The cell viability and adipocyte differentiation were analyzed by alamarBlue™ assay, Oil Red O staining, and RT‐qPCR. The expression of genes: Pref‐1, C/EBP β, C/EBP α, PPAR‐ƴ, SLC2A4, and VEGF‐A were quantified. The cell viability results show that the 50% CM showed significantly higher cell pre‐adipocyte cell viability. In addition, compared to normal conditions, hypoxia/CM provided higher PPAR‐ƴ (p < .05), SLC2A4, and VEGF‐A (p < .05) (early and terminal differentiating markers) mRNA expression. This finding demonstrates the efficacy of amniotic CM supplementation as a novel way to promote adipocyte survival and retention via the expression of key gene markers for differentiation and angiogenesis.

Fabrication and characterization of a pro-angiogenic hydrogel derived from the human placenta

Various hydrogels derived from the xenogeneic extracellular matrix (ECM) have been utilised to promote the repair and reconstruction of numerous tissues; however, there are few studies on hydrogels derived from allogeneic specimens. Human placenta derived hydrogels have been used in the therapy of ischaemic myocardium; however, their physicochemical properties and effects on cellular behaviour remain elusive. As the human placenta retains pro-angiogenic growth factors, it is hypothesized that the placenta hydrogels possess the potential to improve angiogenesis. In this study, a soluble decellularized human placenta matrix generated using a modified method could be stored in a powder form and could be used to form a hydrogel in vitro. Effective decellularization was evaluated by analysing the DNA content and histology images. The placenta hydrogel exhibited a fibrous porous morphology and was injectable. Fourier transform infrared (FTIR) spectroscopy revealed that the placenta hydrogel contained both collagen and sulfated glycosaminoglycans (GAGs). In addition, immunofluorescence imaging and enzyme-linked immunosorbent assay (ELISA) showed that the placenta hydrogel retained pro-angiogenic growth factors, including VEGF and bFGF, and transforming growth factor-β1 (TGF-β1). Further in vitro and in vivo analyses confirmed that the placenta hydrogel exerted better pro-angiogenic effects than a collagen type I hydrogel. Histological data also showed that the placenta hydrogels did not elicit a grave inflammatory response. In conclusion, the results suggest that placenta hydrogels may be deemed an attractive scaffold for regenerative medicine applications, especially in promoting vessel formation.

Human Amniotic Membrane for the Treatment of Cryptoglandular Anal Fistulas

Background: Implantation of the amniotic membrane and their derivatives can have a beneficial effect on tissue repair and regeneration. We report for the first time the implant of an amniotic membrane in a patient affected by cryptoglandular anal fistula. Methods: A patch of human amniotic membrane was implanted in a female patient affected by an anterior transphincteric fistula. Following an accurate curettage of the anal fistula, the cryopreserved amniotic membrane was thawed and then washed in the operating room; one side of the membrane was transfixed with a resorbable suture thus creating an implantable fusiform patch. The membrane was subsequently implanted into the fistula tract from the external to the internal opening. The inner and outer parts of the membrane were then sutured to the internal and external fistula openings. Results: No intraoperative or postoperative complications occurred. The patient was discharged one day after the procedure after an uneventful hospitalization. At the 1-week, 1- and 3-month follow-up visits no pain (VAS 0) was referred by the patient and no inflammation was evident at the level of the previous external fistula opening. Conclusions: The implant of human amniotic membrane in a patient affected by cryptoglandular anal fistula was safely and easily performed. Moreover, future studies to assess the efficacy in the long-term follow-up are needed.

Acellular human amniotic fluid protects the ischemic/reperfused rat myocardium

Amniotic products are potent immunomodulators utilized clinically to repair tissue injury. Little information exists regarding the potential of cell-free human amniotic fluid (hAF) to treat cardiovascular disease. Herein, we sought to determine the influence and efficacy of acellular hAF on myocardial ischemia/reperfusion injury. Processed hAF was obtained from volunteer donors at the time of elective caesarean section and manufactured using proprietary methods. Left anterior descending coronary artery ligation was performed on rats for 60 minutes. Thirty minutes after release and reperfusion, either saline or hAF was injected intramyocardially. Serial echocardiography revealed that compared to saline injected rats, hAF animals maintained their ejection fraction and did not adversely remodel through the 4-week period. This preserved ventricular function correlated with decreased infarct size, less fibrosis, and reduced expression of cytokines and infiltrating inflammatory cells. Comparative arrays of different donor hAF lots confirmed the presence of a wide array of immunomodulatory and host-defense proteins. The observed functional cardioprotection was furthermore evident when given intravenously and across multiple hAF donors. In conclusion, our data demonstrate, for the first time, the cardioprotective effect of acellular hAF on myocardial injury. These observations spanned across diverse donors and likely result from the mixture of a plethora of naturally produced cytokines, chemokines, and immune-modulating proteins rather than a single, defined mechanistic culprit. The ubiquitous availability of hAF as a cell-free solution further suggests its potential for widespread adoption as a therapy for myocardial ischemia/reperfusion injury.

Perinatal derivatives: How to best characterize their multimodal functions in vitro. Part C: Inflammation, angiogenesis, and wound healing

Perinatal derivatives (PnD) are birth-associated tissues, such as placenta, umbilical cord, amniotic and chorionic membrane, and thereof-derived cells as well as secretomes. PnD play an increasing therapeutic role with beneficial effects on the treatment of various diseases. The aim of this review is to elucidate the modes of action of non-hematopoietic PnD on inflammation, angiogenesis and wound healing. We describe the source and type of PnD with a special focus on their effects on inflammation and immune response, on vascular function as well as on cutaneous and oral wound healing, which is a complex process that comprises hemostasis, inflammation, proliferation (including epithelialization, angiogenesis), and remodeling. We further evaluate the different in vitro assays currently used for assessing selected functional and therapeutic PnD properties. This review is a joint effort from the COST SPRINT Action (CA17116) with the intention to promote PnD into the clinics. It is part of a quadrinomial series on functional assays for validation of PnD, spanning biological functions, such as immunomodulation, anti-microbial/anti-cancer activities, anti-inflammation, wound healing, angiogenesis, and regeneration.

Mohs Defect Repair with Dehydrated Human Amnion/Chorion Membrane

Importance: Reconstructing cosmetically sensitive defects in an aging population undergoing multiple Mohs micrographic surgeries (MMS) may be addressed with alternatives to surgery.

Objective: Patients undergoing MMS with defect reconstruction in visually prominent areas receiving placental allograft were compared with traditional autologous tissue-based procedures—flaps and full-thickness skin grafts (FTSG).

Design, Setting, and Participants: This retrospective case–control study evaluated patients who underwent MMS for removal of a basal or squamous cell carcinoma with same-day repair.

Main Outcomes and Measures: The primary endpoint was the incidence and comparison of postoperative morbidity. Risk for developing medical or cosmetic sequelae was determined through multivariate logistic regression.

Results: The study population consisted of 143 propensity score-matched pairs (n = 286) with moderate- to high-risk defects on the face, head, and neck. Compared with autologous tissue, placental allograft cases were associated with significantly lower risk for infection (p = 0.004), poor scar cosmesis (p < 0.0001), scar revision (p < 0.0001), or reoperation (p = 0.0007).

Conclusions and Relevance: Postoperative complication rates for placental reconstructions did not exceed those demonstrated by autologous tissue counterparts, indicating this is a safe alternative to flap and FTSG in cosmetically sensitive repairs.

CM from intact hAM: an easily obtained product with relevant implications for translation in regenerative medicine

Background

It is now well established that factors (free or in extracellular vesicles) secreted by mesenchymal stromal cells (MSC) are important mediators of MSC regenerative actions. Herein we produced the secretome (conditioned medium, CM) from MSC isolated from the amniotic membrane (hAMSC) and CM from the intact amniotic membrane (hAM, no manipulation or enzymatic digestion) in order to potentially identify an effective, easy and less expensive secretome to produce for potential applications in regenerative medicine. Given that immunomodulation is a key mechanism of action through which hAMSC contributes to tissue regeneration, we used a comprehensive panel of in vitro immunomodulatory tests to compare the CMs.

Methods

Amniotic membranes were either cut into fragments or used for hAMSC isolation. CMs from hAMSC at passages 0 and 2 were collected after a standard 5-day culture while CM from hAM was collected after a 2- and 5-day culture. Immunomodulation was assessed in terms of PBMC and T-cell proliferation, T-cell subset polarization, T-regulatory cell induction, cell cytotoxicity and monocyte differentiation toward antigen-presenting cells. Furthermore, we performed a comparison between CM obtained from single donors and pooled CM. We also assessed the impact of lyophilization on the immunomodulatory properties of CM.

Results

We demonstrate that CM from hAM has comparable immunomodulatory properties to CM from hAMSC at passages 0 and 2. Furthermore, we demonstrate that pooled CMs have similar effects when compared to CM from single donors used separately. Finally, we demonstrate that lyophilization does not alter the in vitro immunomodulatory properties of CM from hAM and hAMSC.

Conclusions

The results presented herein support the possibility to produce secretome from intact hAM and open the prospect to highly improve the scalability of the GMP production process while reducing the costs and time related to the process of cell isolation and expansion. Moreover, the possibility of having a lyophilized secretome that maintains its original properties would allow for a ready-to-use product with easier handling, shipping and storage. The use of a lyophilized product will also facilitate clinicians by permitting customized reconstitution volumes and methods according to the most suitable formula required by the clinical application.

Systematic Review of the Application of Perinatal Derivatives in Animal Models on Cutaneous Wound Healing

Knowledge of the beneficial effects of perinatal derivatives (PnD) in wound healing goes back to the early 1900s when the human fetal amniotic membrane served as a biological dressing to treat burns and skin ulcerations. Since the twenty-first century, isolated cells from perinatal tissues and their secretomes have gained increasing scientific interest, as they can be obtained non-invasively, have anti-inflammatory, anti-cancer, and anti-fibrotic characteristics, and are immunologically tolerated in vivo. Many studies that apply PnD in pre-clinical cutaneous wound healing models show large variations in the choice of the animal species (e.g., large animals, rodents), the choice of diabetic or non-diabetic animals, the type of injury (full-thickness wounds, burns, radiation-induced wounds, skin flaps), the source and type of PnD (placenta, umbilical cord, fetal membranes, cells, secretomes, tissue extracts), the method of administration (topical application, intradermal/subcutaneous injection, intravenous or intraperitoneal injection, subcutaneous implantation), and the type of delivery systems (e.g., hydrogels, synthetic or natural biomaterials as carriers for transplanted cells, extracts or secretomes). This review provides a comprehensive and integrative overview of the application of PnD in wound healing to assess its efficacy in preclinical animal models. We highlight the advantages and limitations of the most commonly used animal models and evaluate the impact of the type of PnD, the route of administration, and the dose of cells/secretome application in correlation with the wound healing outcome. This review is a collaborative effort from the COST SPRINT Action (CA17116), which broadly aims at approaching consensus for different aspects of PnD research, such as providing inputs for future standards for the preclinical application of PnD in wound healing.

COVID-19 and the role of stem cells

There is currently an ongoing coronavirus respiratory disease (COVID-19) pandemic that is caused by SARS-CoV-2 virus, which emerged out of Wuhan, China. In severe cases, the disease can progress to respiratory distress, hypoxia, and multi-organ failure, all of which are associated with high mortality. Mesenchymal stem cells (MSCs) possess potent and broad-ranging immunomodulatory activities. MSCs have demonstrated their impressive ability to inhibit lung damage, reduce inflammation, attenuate the immune response, and aid with alveolar fluid clearance. Studies that investigated the use of MSCs and exosome cells derived from MSCs in treating COVD-19 patients have encouraging results. The conclusion of the results of four clinical studies, as presented in this review article, is reduced patient mortality in more than half of the subjects who were administered MSCs or exosomes derived from MSCs, intravenously, positioning these cells as a possible therapeutic solution for COVID-19. While the studies do have limitations, they do provide a stepping stone based on different approaches in the search for treatment to save patients.

Detrimental Effect of Various Preparations of the Human Amniotic Membrane Homogenate on the 2D and 3D Bladder Cancer In vitro Models

Despite being among the ten most common cancers with high recurrence rates worldwide, there have been no major breakthroughs in the standard treatment options for bladder cancer in recent years. The use of a human amniotic membrane (hAM) to treat cancer is one of the promising ideas that have emerged in recent years. This study aimed to investigate the anticancer activity of hAM homogenate on 2D and 3D cancer models. We evaluated the effects of hAM homogenates on the human muscle invasive bladder cancer urothelial (T24) cells, papillary cancer urothelial (RT4) cells and normal porcine urothelial (NPU) cells as well as on human mammary gland non-tumorigenic (MCF10a) cells and low-metastatic breast cancer (MCF7) cells. After 24 h, we observed a gradual detachment of cancerous cells from the culture surface, while the hAM homogenate did not affect the normal cells. The most pronounced effect hAM homogenate had on bladder cancer cells; however, the potency of their detachment was dependent on the treatment protocol and the preparation of hAM homogenate. We demonstrated that hAM homogenate significantly decreased the adhesion, growth, and proliferation of human bladder invasive and papillary cancer urothelial cells and did not affect normal urothelial cells even in 7-day treatment. By using light and electron microscopy we showed that hAM homogenate disrupted the architecture of 2D and 3D bladder cancer models. The information provided by our study highlights the detrimental effect of hAM homogenate on bladder cancer cells and strengthens the idea of the potential clinical application of hAM for bladder cancer treatment.

Placenta: A gold mine for translational research and regenerative medicine

Stem cell therapy has gained much impetus in regenerative medicine due to some of the encouraging results obtained in the laboratory as well as in translational/clinical studies. Although stem cells are of various types and their therapeutic potential has been documented in several studies, mesenchymal stromal/stem cells (MSCs) have an edge, as in addition to being multipotent, these cells are easy to obtain and expand, pose fewer ethical issues, and possess immense regenerative potential when used in a scientifically correct manner. Currently, MSCs are being sourced from various tissues such as bone marrow, cord, cord blood, adipose tissue, dental tissue, etc., and, quite often, the choice depends on the availability of the source. One such rich source of tissue suitable for obtaining good quality MSCs in large numbers is the placenta obtained in a full-term delivery leading to a healthy child's birth. Several studies have demonstrated the regenerative potential of human placenta-derived MSCs (hPMSC), and most show that these MSCs possess comparable, in some instances, even better, therapeutic potential as that shown by human bone marrow-derived (hBMSC) or human umbilical cord-derived (hUC-MSC) MSCs. The placenta can be easily sourced from the OB/GYN department of any hospital, and if its derivatives such as hPMSC or their EVs are produced under GMP conditions, it could serve as a gold mine for translational/clinical research. Here, we have reviewed recent studies revealing the therapeutic potential of hPMSC and their extracellular vesicles (EVs) published over the past three years.

Effects of Preservation Methods in the Composition of the Placental and Reflected Regions of the Human Amniotic Membrane

The human amniotic membrane (AM) is emerging as an interesting biomaterial for regenerative medicine due to its biological and mechanical proprieties. The beneficial effects of the AM are probably related to its bioactive factors produced by local cells and stored in the stromal matrix. However, the search for a preservation method capable of preserving AM properties remains a challenge. The aim of this study was to evaluate important features of 2 anatomical regions of the human AM (reflected and placental amnion) after different preservation methods. For this purpose, human placentas were harvested and processed for AM isolation and storage at 2 different conditions: room temperature for 18 h in DMEM (fresh AM) and -80°C in DMEM/glycerol solution for 30 days (cryopreserved AM). After the storage period, the structural integrity of the membrane was assessed by histological and Picrosirius polarization analysis, cellular viability analysis was performed using the MTT assay, and the soluble proteins were quantified with the Qubit Protein Assay Kit. Both preservation protocols reduced the cell viability, mainly in the placental amnion region of the AM, but preserved the morphology of epithelial and stromal layers, as well as the organization and distribution of collagen fibers. There was a reduction in soluble proteins only in fresh AM. Importantly, the cryopreserved AM group presented the same concentration as the control group. In conclusion, the cryopreservation using DMEM/glycerol was ideal for preserving the structural integrity and soluble protein content, indicating the feasibility of this method in preserving AM for its use in regenerative medicine.

Mesenchymal Stromal Cells and Their Secretome: New Therapeutic Perspectives for Skeletal Muscle Regeneration

Mesenchymal stromal cells (MSCs) are multipotent cells found in different tissues: bone marrow, peripheral blood, adipose tissues, skeletal muscle, perinatal tissues, and dental pulp. MSCs are able to self-renew and to differentiate into multiple lineages, and they have been extensively used for cell therapy mostly owing to their anti-fibrotic and immunoregulatory properties that have been suggested to be at the basis for their regenerative capability. MSCs exert their effects by releasing a variety of biologically active molecules such as growth factors, chemokines, and cytokines, either as soluble proteins or enclosed in extracellular vesicles (EVs). Analyses of MSC-derived secretome and in particular studies on EVs are attracting great attention from a medical point of view due to their ability to mimic all the therapeutic effects produced by the MSCs (i.e., endogenous tissue repair and regulation of the immune system). MSC-EVs could be advantageous compared with the parental cells because of their specific cargo containing mRNAs, miRNAs, and proteins that can be biologically transferred to recipient cells. MSC-EV storage, transfer, and production are easier; and their administration is also safer than MSC therapy. The skeletal muscle is a very adaptive tissue, but its regenerative potential is altered during acute and chronic conditions. Recent works demonstrate that both MSCs and their secretome are able to help myofiber regeneration enhancing myogenesis and, interestingly, can be manipulated as a novel strategy for therapeutic interventions in muscular diseases like muscular dystrophies or atrophy. In particular, MSC-EVs represent promising candidates for cell free-based muscle regeneration. In this review, we aim to give a complete picture of the therapeutic properties and advantages of MSCs and their products (MSC-derived EVs and secreted factors) relevant for skeletal muscle regeneration in main muscular diseases.

Basic and Preclinical Research for Personalized Medicine

Basic and preclinical research founded the progress of personalized medicine by providing a prodigious amount of integrated profiling data and by enabling the development of biomedical applications to be implemented in patient-centered care and cures. If the rapid development of genomics research boosted the birth of personalized medicine, further development in omics technologies has more recently improved our understanding of the functional genome and its relevance in profiling patients’ phenotypes and disorders. Concurrently, the rapid biotechnological advancement in diverse research areas enabled uncovering disease mechanisms and prompted the design of innovative biological treatments tailored to individual patient genotypes and phenotypes. Research in stem cells enabled clarifying their role in tissue degeneration and disease pathogenesis while providing novel tools toward the development of personalized regenerative medicine strategies. Meanwhile, the evolving field of integrated omics technologies ensured translating structural genomics information into actionable knowledge to trace detailed patients’ molecular signatures. Finally, neuroscience research provided invaluable models to identify preclinical stages of brain diseases. This review aims at discussing relevant milestones in the scientific progress of basic and preclinical research areas that have considerably contributed to the personalized medicine revolution by bridging the bench-to-bed gap, focusing on stem cells, omics technologies, and neuroscience fields as paradigms.

Stem cells and COVID-19: are the human amniotic cells a new hope for therapies against the SARS-CoV-2 virus?

A new coronavirus respiratory disease (COVID-19) caused by the SARS-CoV-2 virus, surprised the entire world, producing social, economic, and health problems. The COVID-19 triggers a lung infection with a multiple proinflammatory cytokine storm in severe patients. Without effective and safe treatments, COVID-19 has killed thousands of people, becoming a pandemic. Stem cells have been suggested as a therapy for lung-related diseases. In particular, mesenchymal stem cells (MSCs) have been successfully tested in some clinical trials in patients with COVID-19. The encouraging results positioned MSCs as a possible cell therapy for COVID-19. The amniotic membrane from the human placenta at term is a valuable stem cell source, including human amniotic epithelial cells (hAECs) and human mesenchymal stromal cells (hAMSCs). Interestingly, amnion cells have immunoregulatory, regenerative, and anti-inflammatory properties. Moreover, hAECs and hAMSCs have been used both in preclinical studies and in clinical trials against respiratory diseases. They have reduced the inflammatory response and restored the pulmonary tissue architecture in lung injury in vivo models. Here, we review the existing data about the stem cells use for COVID-19 treatment, including the ongoing clinical trials. We also consider the non-cellular therapies that are being applied. Finally, we discuss the human amniotic membrane cells use in patients who suffer from immune/inflammatory lung diseases and hypothesize their possible use as a successful treatment against COVID-19.

The Antibacterial Activity of Human Amniotic Membrane against Multidrug-Resistant Bacteria Associated with Urinary Tract Infections: New Insights from Normal and Cancerous Urothelial Models

Urinary tract infections (UTIs) represent a serious global health issue, especially due to emerging multidrug-resistant UTI-causing bacteria. Recently, we showed that the human amniotic membrane (hAM) could be a candidate for treatments and prevention of UPEC and Staphylococcus aureus infections. However, its role against multidrug-resistant bacteria, namely methicillin-resistant S. aureus (MRSA), extended-spectrum beta-lactamases (ESBL) producing Escherichia coli and Klebsiella pneumoniae, vancomycin-resistant Enterococci (VRE), carbapenem-resistant Acinetobacter baumannii, and Pseudomonas aeruginosa has not yet been thoroughly explored. Here, we demonstrate for the first time that the hAM homogenate had antibacterial activity against 7 out of 11 tested multidrug-resistant strains, the greatest effect was on MRSA. Using novel approaches, its activity against MRSA was further evaluated in a complex microenvironment of normal and cancerous urinary bladder urothelia. Even short-term incubation in hAM homogenate significantly decreased the number of bacteria in MRSA-infected urothelial models, while it did not affect the viability, number, and ultrastructure of urothelial cells. The hAM patches had no antibacterial activity against any of the tested strains, which further exposes the importance of the hAM preparation. Our study substantially contributes to basic knowledge on the antibacterial activity of hAM and reveals its potential to be used as an antibacterial agent against multidrug-resistant bacteria.

Human amniotic mesenchymal stem cells to promote/suppress cancer: two sides of the same coin

Cancer is a leading cause of death in both developed and developing countries, and because of population growth and aging, it is a growing medical burden worldwide. With robust development in medicine, the use of stem cells has opened new treatment modalities in cancer therapy. In adult stem cells, mesenchymal stem cells (MSCs) are showing rising promise in cancer treatment due to their unique properties. Among different sources of MSCs, human amniotic fluid/membrane is an attractive and suitable reservoir. There are conflicting opinions about the role of human amniotic membrane/fluid mesenchymal stem cells (hAMSCS/hAFMSCs) in cancer, as some studies demonstrating the anticancer effects of these cells and others suggesting their progressive effects on cancer. This review focuses on recent findings about the role of hAMSCs/hAFMSCs in cancer treatment and summarizes the suppressing as well as promoting effects of these cells on cancer progression and underling mechanisms.

Perinatal Cells: A Promising COVID-19 Therapy?

The COVID-19 pandemic has become a priority in the health systems of all nations worldwide. In fact, there are currently no specific drugs or preventive treatments such as vaccines. The numerous therapies available today aim to counteract the symptoms caused by the viral infection that in some subjects can evolve causing acute respiratory distress syndromes (ARDS) with consequent admission to intensive care unit. The exacerbated response of the immune system, through cytokine storm, causes extensive damage to the lung tissue, with the formation of edema, fibrotic tissues and susceptibility to opportunistic infections. The inflammatory picture is also aggravated by disseminated intravascular coagulation which worsens the damage not only to the respiratory system, but also to other organs. In this context, perinatal cells represent a valid strategy thanks to their strong immunomodulatory potential, their safety profile, the ability to reduce fibrosis and stimulate reparative processes. Furthermore, perinatal cells exert antibacterial and antiviral actions. This review therefore provides an overview of the characteristics of perinatal cells with a particular focus on the beneficial effects that they could have in patients with COVID-19, and more specifically for their potential use in the treatment of ARDS and sepsis.

Sub-Regional Differences of the Human Amniotic Membrane and Their Potential Impact on Tissue Regeneration Application

For more than 100 years, the human amniotic membrane (hAM) has been used in multiple tissue regeneration applications. The hAM consists of cells with stem cell characteristics and a rich layer of extracellular matrix. Undoubtedly, the hAM with viable cells has remarkable properties such as the differentiation potential into all three germ layers, immuno-modulatory, and anti-fibrotic properties. At first sight, the hAM seems to be one structural entity. However, by integrating its anatomical location, the hAM can be divided into placental, reflected, and umbilical amniotic membrane. Recent studies show that cells of these amniotic sub-regions differ considerably in their properties such as morphology, structure, and content/release of certain bioactive factors. The aim of this review is to summarize these findings and discuss the relevance of these different properties for tissue regeneration. In summary, reflected amnion seems to be more immuno-modulatory and could have a higher reprogramming efficiency, whereas placental amnion seems to be pro-inflammatory, pro-angiogenic, with higher proliferation and differentiation capacity (e.g., chondrogenic and osteogenic), and could be more suitable for certain graft constructions. Therefore, we suggest that the respective hAM sub-region should be selected in consideration of its desired outcome. This will help to optimize and fine-tune the clinical application of the hAM.

Long-term preservation effects on biological properties of acellular placental sponge patches

Decellularization, preservation protocol and storage time influence the biomechanical and biological properties of allografts and xenografts. Here, we examined the consequences of storage time on the antibacterial, angiogenic and biocompatibility properties of the decellularized placental sponge (DPS) in vitro and in vivo. The DPS samples were preserved for one, three and six months at -20 °C. The decellularized scaffolds showed uniform morphology with interconnected pores compared with not decellularized sponges. Storage time did not interfere with collagen and vascular endothelial growth factor contents, and cytobiocompatibility for Hu02 fibroblast cells. Chorioallantoic membrane assay and subcutaneous implantation indicated a decreased new vessel formation and neovascularization in six months DPS sample compared with other experimental groups. The number of CD4⁺ and CD68⁺ cells infiltrated into the six months DPS on the implanted site showed a significant increase compared with one and three months sponges. The antibacterial activities and angiogenic properties of the DPS decreased over storage time. Three months preservation at -20 °C is suggested as the optimal storage period to retain its antibacterial activity and high stimulation of new vessel formation. This storage protocol could be considered for preservation of similar decellularized placenta-derived products with the aim of retaining their biological properties.

Effect of Diphenyleneiodonium Chloride on Intracellular Reactive Oxygen Species Metabolism with Emphasis on NADPH Oxidase and Mitochondria in Two Therapeutically Relevant Human Cell Types

Reactive oxygen species (ROS) have recently been recognized as important signal transducers, particularly regulating proliferation and differentiation of cells. Diphenyleneiodonium (DPI) is known as an inhibitor of the nicotinamide adenine dinucleotide phosphate oxidase (NOX) and is also affecting mitochondrial function. The aim of this study was to investigate the effect of DPI on ROS metabolism and mitochondrial function in human amniotic membrane mesenchymal stromal cells (hAMSCs), human bone marrow mesenchymal stromal cells (hBMSCs), hBMSCs induced into osteoblast-like cells, and osteosarcoma cell line MG-63. Our data suggested a combination of a membrane potential sensitive fluorescent dye, tetramethylrhodamine methyl ester (TMRM), and a ROS-sensitive dye, CM-H2DCFDA, combined with a pretreatment with mitochondria-targeted ROS scavenger MitoTEMPO as a good tool to examine effects of DPI. We observed critical differences in ROS metabolism between hAMSCs, hBMSCs, osteoblast-like cells, and MG-63 cells, which were linked to energy metabolism. In cell types using predominantly glycolysis as the energy source, such as hAMSCs, DPI predominantly interacted with NOX, and it was not toxic for the cells. In hBMSCs, the ROS turnover was influenced by NOX activity rather than by the mitochondria. In cells with aerobic metabolism, such as MG 63, the mitochondria became an additional target for DPI, and these cells were prone to the toxic effects of DPI. In summary, our data suggest that undifferentiated cells rather than differentiated parenchymal cells should be considered as potential targets for DPI.

Perinatal Derivatives: Where Do We Stand? A Roadmap of the Human Placenta and Consensus for Tissue and Cell Nomenclature

Progress in the understanding of the biology of perinatal tissues has contributed to the breakthrough revelation of the therapeutic effects of perinatal derivatives (PnD), namely birth-associated tissues, cells, and secreted factors. The significant knowledge acquired in the past two decades, along with the increasing interest in perinatal derivatives, fuels an urgent need for the precise identification of PnD and the establishment of updated consensus criteria policies for their characterization. The aim of this review is not to go into detail on preclinical or clinical trials, but rather we address specific issues that are relevant for the definition/characterization of perinatal cells, starting from an understanding of the development of the human placenta, its structure, and the different cell populations that can be isolated from the different perinatal tissues. We describe where the cells are located within the placenta and their cell morphology and phenotype. We also propose nomenclature for the cell populations and derivatives discussed herein. This review is a joint effort from the COST SPRINT Action (CA17116), which broadly aims at approaching consensus for different aspects of PnD research, such as providing inputs for future standards for the processing and in vitro characterization and clinical application of PnD.

Electrospun PCL/PLA Scaffolds Are More Suitable Carriers of Placental Mesenchymal Stromal Cells Than Collagen/Elastin Scaffolds and Prevent Wound Contraction in a Mouse Model of Wound Healing

Mesenchymal stem/stromal cells (MSCs) exert beneficial effects during wound healing, and cell-seeded scaffolds are a promising method of application. Here, we compared the suitability of a clinically used collagen/elastin scaffold (Matriderm) with an electrospun Poly(ε-caprolactone)/poly(l-lactide) (PCL/PLA) scaffold as carriers for human amnion-derived MSCs (hAMSCs). We created an epidermal-like PCL/PLA scaffold and evaluated its microstructural, mechanical, and functional properties. Sequential spinning of different PCL/PLA concentrations resulted in a wide-meshed layer designed for cell-seeding and a dense-meshed layer for apical protection. The Matriderm and PCL/PLA scaffolds then were seeded with hAMSCs, with or without Matrigel coating. The quantity and quality of the adherent cells were evaluated in vitro. The results showed that hAMSCs adhered to and infiltrated both scaffold types but on day 3, more cells were observed on PCL/PLA than on Matriderm. Apoptosis and proliferation rates were similar for all carriers except the coated Matriderm, where apoptotic cells were significantly enhanced. On day 8, the number of cells decreased on all carrier types except the coated Matriderm, which had consistently low cell numbers. Uncoated Matriderm had the highest percentage of proliferative cells and lowest apoptosis rate of all carrier types. Each carrier also was topically applied to skin wound sites in a mouse model and analyzed in vivo over 14 days via optical imaging and histological methods, which showed detectable hAMSCs on all carrier types on day 8. On day 14, all wounds exhibited newly formed epidermis, and all carriers were well-integrated into the underlying dermis and showing signs of degradation. However, only wounds treated with uncoated PCL/PLA maintained a round appearance with minimal contraction. Overall, the results support a 3-day in vitro culture of scaffolds with hAMSCs before wound application. The PCL/PLA scaffold showed higher cell adherence than Matriderm, and the effect of the Matrigel coating was negligible, as all carrier types maintained sufficient numbers of transplanted cells in the wound area. The anti-contractive effects of the PCL/PLA scaffold offer potential new therapeutic approaches to wound care.

Insights on the Human Amniotic Membrane in Clinical Practice with a Focus on the New Applications in Retinal Surgery

Recently, the use of the human amniotic membrane (hAM) has been extended to treat retinal disorders such as refractory macular holes, retinal breaks and dry and wet age-related macular degeneration. Not only the hAM has proved to be an excellent tool for repairing retinal tissue, but it has also shown a promising regeneration potential. This review aims to highlight the novel use of the hAM in treating retinal diseases. Although the hAM has been used in the ocular anterior segment reconstruction for more than 60 years, in the last 2 years, we have found in literature articles showing the use of the hAM in the retinal surgery field with interesting results in terms of tissue healing and photoreceptor regeneration.

Riboflavin-mediated photooxidation to improve the characteristics of decellularized human arterial small diameter vascular grafts

Vascular grafts with a diameter of less than 6 mm are made from a variety of materials and techniques to provide alternatives to autologous vascular grafts. Decellularized materials have been proposed as a possible approach to create extracellular matrix (ECM) vascular prostheses as they are naturally derived and inherently support various cell functions. However, these desirable graft characteristics may be limited by alterations of the ECM during the decellularization process leading to decreased biomechanical properties and hemocompatibility. In this study, arteries from the human placenta chorion were decellularized using two distinct detergents (Triton X-100 or SDS), which differently affect ECM ultrastructure. To overcome biomechanical strength loss and collagen fiber exposure after decellularization, riboflavin-mediated UV (RUV) crosslinking was used to uniformly crosslink the collagenous ECM of the grafts. Graft characteristics and biocompatibility with and without RUV crosslinking were studied in vitro and in vivo. RUV-crosslinked ECM grafts showed significantly improved mechanical strength and smoothening of the luminal graft surfaces. Cell seeding using human endothelial cells revealed no cytotoxic effects of the RUV treatment. Short-term aortic implants in rats showed cell migration and differentiation of host cells. Functional graft remodeling was evident in all grafts. Thus, RUV crosslinking is a preferable tool to improve graft characteristics of decellularized matrix conduits.

Assessment of the in vivo biofunctionality of a biomimetic hybrid scaffold for osteochondral tissue regeneration

Chondral and osteochondral lesions represent one of the most challenging problems in the orthopedic field, as these types of injuries lead to disability and worsened quality of life for patients and have an economic impact on the healthcare system. The aim of this in vivo study was to develop a new tissue engineering approach through a hybrid scaffold for osteochondral tissue regeneration made of porous polyurethane foam (PU) coated under vacuum with calcium phosphates (PU/VAC). Scaffold characterization showed a highly porous and interconnected structure. Human amniotic mesenchymal stromal cells (hAMSCs) were loaded into scaffolds using pectin (PECT) as a carrier. Osteochondral defects in medial femoral condyles of rabbits were created and randomly allocated in one of the following groups: plain scaffold (PU/VAC), scaffold with hAMSCs injected in the implant site (PU/VAC/hAMSC), scaffold with hAMSCs loaded in pectin (PU/VAC/PECT/hAMSC), and no treated defects (untreated). The therapeutic efficacy was assessed by macroscopic, histological, histomorphometric, microtomographic, and ultrastructural analyses at 3, 6, 12, and 24 weeks. Histological results showed that the scaffold was permissive to tissue growth and penetration, an immature osteocartilaginous tissue was observed at early experimental times, with a more accentuated bone regeneration in comparison with the cartilage layer in the absence of any inflammatory reaction.

Human amniotic stem cells improve hepatic microvascular dysfunction and portal hypertension in cirrhotic rats

BACKGROUND AND AIMS

Portal hypertension is the main consequence of cirrhosis, responsible for the complications defining clinical decompensation. The only cure for decompensated cirrhosis is liver transplantation, but it is a limited resource and opens the possibility of regenerative therapy. We investigated the potential of primary human amniotic membrane-derived mesenchymal stromal (hAMSCs) and epithelial (hAECs) stem cells for the treatment of portal hypertension and decompensated cirrhosis.

METHODS

In vitro: Primary liver sinusoidal endothelial cells (LSECs) and hepatic stellate cells (HSCs) from cirrhotic rats (chronic CCl₄ inhalation) were co-cultured with hAMSCs, hAECs or vehicle for 24 hours, and their RNA profile was analysed. In vivo: CCl₄-cirrhotic rats received 4x10⁶ hAMSCs, 4x10⁶ hAECs, or vehicle (NaCl 0.9%) (intraperitoneal). At 2-weeks we analysed: a) portal pressure (PP) and hepatic microvascular function; b) LSECs and HSCs phenotype; c) hepatic fibrosis and inflammation.

RESULTS

In vitro experiments revealed sinusoidal cell phenotype amelioration when co-cultured with stem cells. Cirrhotic rats receiving stem cells, particularly hAMSCs, had significantly lower PP than vehicle-treated animals, together with improved liver microcirculatory function. This hemodynamic amelioration was associated with improvement in LSECs capillarization and HSCs de-activation, though hepatic collagen was not reduced. Rats that received amnion derived stem cells had markedly reduced hepatic inflammation and oxidative stress. Finally, liver function tests significantly improved in rats receiving hAMSCs.

CONCLUSIONS

This preclinical study shows that infusion of human amniotic stem cells effectively decreases PP by ameliorating liver microcirculation, suggesting that it may represent a new treatment option for advanced cirrhosis with portal hypertension.