Update review on five top clinical applications of human amniotic membrane in regenerative medicine

Optimization of a nanoparticle uptake protocol applied to amniotic-derived cells: unlocking the therapeutic potential

Stem cell-based therapy implementation relies heavily on advancements in cell tracking. The present research has been designed to develop a gold nanorod (AuNR) labeling protocol applied to amniotic epithelial cells (AECs) leveraging the pro-regenerative properties of this placental stem cell source which is widely used for both human and veterinary biomedical regenerative applications, although not yet exploited with tracking technologies. Ovine AECs, in native or induced mesenchymal (mAECs) phenotypes via epithelial-mesenchymal transition (EMT), served as the model. Initially, various uptake methods validated on other sources of mesenchymal stromal cells (MSCs) were assessed on mAECs before optimization for AECs. Furthermore, the protocol was implemented by adopting the biological strategy of MitoCeption to improve endocytosis. The results indicate that the most efficient, affordable, and easy protocol leading to internalization of AuNRs in living mAECs recognized the combination of the one-step uptake condition (cell in suspension), centrifugation-mediated internalization method (G-force) and MitoCeption (mitochondrial isolated from mAECs). This protocol produced labeled vital mAECs within minutes, suitable for preclinical and clinical trials. The optimized protocol has the potential to yield feasible labeled amniotic-derived cells for biomedical purposes: up to 10 million starting from a single amniotic membrane. Similar and even higher efficiency was found when the protocol was applied to ovine and human AECs, thereby demonstrating the transferability of the method to cells of different phenotypes and species-specificity, hence validating its great potential for the development of improved biomedical applications in cell-based therapy and diagnostic imaging.

Potential novel role of the human amniotic membrane as a sustainable hemostat

OBJECTIVES

Acute hemorrhage can cause significant morbidity and mortality arising from trauma, bleeding disorders, surgical procedures, or obstetric complications. Surgical hemostasis methods may fail to stop acute bleeding due to the complex bleeding dynamics of each bleeding type. Therefore, developing safe and effective topical hemostatic agents remains crucial. The human amniotic membrane (hAM) has established clinical evidence of effectiveness in promoting wound healing and tissue regeneration. Despite its unique biological and immunologic properties and its structural composition of established hemostatic elements, the hemostatic role of hAM has not been yet explored. The present study aimed to investigate this potential role and to describe the development protocol and characterization of hAM-derived topical hemostat.

METHODS

Surface electron microscope (SEM) imaging and Fourier transform infrared (FTIR) spectroscopy were used for characterization, and mouse models with induced peritoneal and tail wound bleeding were employed to evaluate the hemostatic effectiveness using physiological studies, in comparison to a chitosan-based combat-scale hemostat.

RESULTS

The hAM hemostat showed a distinctive composition by SEM and FTIR. Applying equal masses of the hAM hemostat, the commercial hemostat, or a combination reduced peritoneal wound bleeding time to averages of 108.4, 86.2, and 76.8 s, respectively, compared to the control group (300 s). Tail wound bleeding times were similarly reduced with no significant difference between the hAM and the commercial hemostat (P values = 0.29, 0.34 in peritoneal and tail wounds, respectively). Neither hemostat affected coagulation time.

CONCLUSION

This study describes a simple cost-effective preparation protocol for a hAM-based hemostatic agent. The long-recognized safety, sustainability, and immunotolerance advantages of hAM can establish superiority over commercial hemostats with reported safety concerns. Robust research validation in larger-scale bleeding models is required for wider applications and severe bleeding types.

Application of pulsed electric field technology to skin engineering

Tissue engineering encompasses a range of techniques that direct the growth of cells into a living tissue construct for regenerative medicine applications, disease models, drug discovery, and safety testing. These techniques have been implemented to alleviate the clinical burdens of impaired healing of skin, bone, and other tissues. Construct development requires the integration of tissue-specific cells and/or an extracellular matrix-mimicking biomaterial for structural support. Production of such constructs is generally expensive and environmentally costly, thus eco-sustainable approaches should be explored. Pulsed electric field (PEF) technology is a nonthermal physical processing method commonly used in food production and biomedical applications. In this review, the key principles of PEF and the application of PEF technology for skin engineering will be discussed, with an emphasis on how PEF can be applied to skin cells to modify their behaviour, and to biomaterials to assist in their isolation or sterilisation, or to modify their physical properties. The findings indicate that the success of PEF in tissue engineering will be reliant on systematic evaluation of key parameters, such as electric field strength, and their impact on different skin cell and biomaterial types. Linking tangible input parameters to biological responses critical to healing will assist with the development of PEF as a sustainable tool for skin repair and other tissue engineering applications.

Comparison of the effects of preservation methods on structural, biological, and mechanical properties of the human amniotic membrane for medical applications

Amniotic membrane (AM), the innermost layer of the placenta, is an exceptionally effective biomaterial with divers applications in clinical medicine. It possesses various biological functions, including scar reduction, anti-inflammatory properties, support for epithelialization, as well as anti-microbial, anti-fibrotic and angio-modulatory effects. Furthermore, its abundant availability, cost-effectiveness, and ethical acceptability make it a compelling biomaterial in the field of medicine. Given the potential unavailability of fresh tissue when needed, the preservation of AM is crucial to ensure a readily accessible and continuous supply for clinical use. However, preserving the properties of AM presents a significant challenge. Therefore, the establishment of standardized protocols for the collection and preservation of AM is vital to ensure optimal tissue quality and enhance patient safety. Various preservation methods, such as cryopreservation, lyophilization, and air-drying, have been employed over the years. However, identifying a preservation method that effectively safeguards AM properties remains an ongoing endeavor. This article aims to review and discuss different sterilization and preservation procedures for AM, as well as their impacts on its histological, physical, and biochemical characteristics.

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.

Inter-placental variability is not a major factor affecting the healing efficiency of amniotic membrane when used for treating chronic non-healing wounds

This study aimed to evaluate the efficacy of cryopreserved amniotic membrane (AM) grafts in chronic wound healing, including the mean percentage of wound closure per one AM application, and to determine whether the healing efficiency differs between AM grafts obtained from different placentas. A retrospective study analyzing inter-placental differences in healing capacity and mean wound closure after the application of 96 AM grafts prepared from nine placentas. Only the placentas from which the AM grafts were applied to patients suffering from long-lasting non-healing wounds successfully healed by AM treatment were included. The data from the rapidly progressing wound-closure phase (p-phase) were analyzed. The mean efficiency for each placenta, expressed as an average of wound area reduction (%) seven days after the AM application (baseline, 100%), was calculated from at least 10 applications. No statistical difference between the nine placentas' efficiency was found in the progressive phase of wound healing. The 7-day average wound reduction in particular placentas varied from 5.70 to 20.99% (median from 1.07 to 17.75) of the baseline. The mean percentage of wound surface reduction of all analyzed defects one week after the application of cryopreserved AM graft was 12.17 ± 20.12% (average ± SD). No significant difference in healing capacity was observed between the nine placentas. The data suggest that if there are intra- and inter-placental differences in AM sheets' healing efficacy, they are overridden by the actual health status of the subject or even the status of its individual wounds.

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.

Outcome of Application of Cryopreserved Amniotic Membrane Grafts in the Treatment of Chronic Nonhealing Wounds of Different Origins in Polymorbid Patients: A Prospective Multicenter Study

To compare the therapeutic efficacy of cryopreserved amniotic membrane (AM) grafts and standard of care (SOC) in treating nonhealing wounds (NHW) through a prospective multicenter clinical trial, 42 patients (76% polymorbid) with 54 nonhealing wounds of various etiologies (mainly venous) and an average baseline size of 20 cm2 were included. All patients were treated for at least 6 weeks in the center before they were involved in the study. In the SOC group, 29 patients (36 wounds) were treated. If the wound healed less than 20% of the baseline size after 6 weeks, the patient was transferred to the AM group (35 patients, 43 wounds). Weekly visits included an assessment of the patient's condition, photo documentation, wound debridement, and dressing. Quality of life and the pain degree were subjectively reported by patients. After SOC, 7 wounds were healed completely, 1 defect partially, and 28 defects remained unhealed. AM application led to the complete closure of 24 wounds, partial healing occurred in 10, and 9 remained unhealed. The degree of pain and the quality of life improved significantly in all patients after AM application. This study demonstrates the effectiveness of cryopreserved AM grafts in the healing of NHW of polymorbid patients and associated pain reduction.

Quantification of Analgesic and Anti-Inflammatory Lipid Mediators in Long-Term Cryopreserved and Freeze-Dried Preserved Human Amniotic Membrane

The aim of this study was to compare concentrations of endogenous N-acylethanolamine (NAE) lipid mediators-palmitoylethanolamide (PEA), oleoylethanolamide (OEA), and anandamide (AEA)-in fresh, decontaminated, cryopreserved, and freeze-dried amniotic membrane (AM) allografts, thereby determining whether AM's analgesic and anti-inflammatory efficiency related to NAEs persists during storage. The concentrations of NAEs were measured using ultra-high-performance liquid chromatography-tandem mass spectrometry. Indirect fluorescent immunohistochemistry was used to detect the PEA PPAR-α receptor. The concentrations of PEA, OEA, and AEA were significantly higher after decontamination. A significant decrease was found in cryopreserved AM compared to decontaminated tissue for PEA but not for OEA and AEA. However, significantly higher values for all NAEs were detected in cryopreserved samples compared to fresh tissue before decontamination. The freeze-dried AM had similar values to decontaminated AM with no statistically significant difference. The nuclear staining of the PPAR-α receptor was clearly visible in all specimens. The stability of NAEs in AM after cryopreservation was demonstrated under tissue bank storage conditions. However, a significant decrease, but still higher concentration of PEA compared to fresh not decontaminated tissue, was found in cryopreserved, but not freeze-dried, AM. Results indicate that NAEs persist during storage in levels sufficient for the analgesic and anti-inflammatory effects. This means that cryopreserved AM allografts released for transplant purposes before the expected expiration (usually 3-5 years) will still show a strong analgesic effect. The same situation was confirmed for AM lyophilized after one year of storage. This work thus contributed to the clarification of the analgesic effect of NAEs in AM allografts.

Connective tissue matrices from placental disc for wound healing: mini-review

Wound management is a complex procedure that includes multiple factors that play major roles in the healing process. Extracellular matrix-based approaches are emerging strategies for promoting wound healing. The extracellular matrix is an extensive three-dimensional molecular network comprising a variety of fibrous proteins, glycosaminoglycans, and proteoglycans. One of the rich sources of extracellular matrix components is placental tissues, which have a long history of use in tissue repair and regeneration. PURPOSE OF WORK: This mini-review focuses on essential characteristics of placental disc, comparison of four commercially available placental connective matrices (Axiofill, Dermavest, Plurivest, and Interfyl) obtained from the placental disc, and their supporting studies in the use of wound healing applications.

Preparation of human amniotic membrane for transplantation in different application areas

The human amniotic membrane (hAM) is the inner layer of the placenta and plays protective and nutritional roles for the fetus during pregnancy. It contains multiple growth factors and proteins that mediate unique regenerative properties and enhance wound healing in tissue regeneration. Due to these characteristics hAM has been successfully utilized in ophthalmology for many decades. This material has also found application in a variety of additional therapeutic areas. Particularly noteworthy are the extraordinary effects in the healing of chronic wounds and in the treatment of burns. But hAM has also been used successfully in gynecology, oral medicine, and plastic surgery and as a scaffold for in vitro cell culture approaches. This review aims to summarize the different graft preparation, preservation and storage techniques that are used and to present advantages and disadvantages of these methods. It shows the characteristics of the hAM according to the processing and storage methods used. The paper provides an overview of the currently mainly used application areas and raises new application possibilities. In addition, further preparation types like extracts, homogenates, and the resulting treatment alternatives are described.

Effects of human placenta cryopreservation on molecular characteristics of placental mesenchymal stromal cells

Cryopreservation of placenta tissue for long-term storage provides the opportunity in the future to isolate mesenchymal stromal cells that could be used for cell therapy and regenerative medicine. Despite being widely used, the established cryopreservation protocols for freezing and thawing still raise concerns about their impact on molecular characteristics, such as epigenetic regulation. In our study, we compared the characteristics of human placental mesenchymal stromal cells (hPMSCs) isolated from fresh (native) and cryopreserved (cryo) placenta tissue. We assessed and compared the characteristics of native and cryo hPMSCs such as morphology, metabolic and differentiation potential, expression of cell surface markers, and transcriptome. No significant changes in immunophenotype and differentiation capacity between native and cryo cells were observed. Furthermore, we investigated the epigenetic changes and demonstrated that both native and cryo hPMSCs express only slight variations in the epigenetic profile, including miRNA levels, DNA methylation, and histone modifications. Nevertheless, transcriptome analysis defined the upregulation of early-senescence state-associated genes in hPMSCs after cryopreservation. We also evaluated the ability of hPMSCs to improve pregnancy outcomes in mouse models. Improved pregnancy outcomes in a mouse model confirmed that isolated placental cells both from native and cryo tissue have a positive effect on the restoration of the reproductive system. Still, the native hPMSCs possess better capacity (up to 66%) in comparison with cryo hPMSCs (up to 33%) to restore fertility in mice with premature ovarian failure. Our study demonstrates that placental tissue can be cryopreserved for long-term storage with the possibility to isolate mesenchymal stromal cells that retain characteristics suitable for therapeutic use.

The use of platelet lysate to increase the growth-stimulating effect of the amniotic membrane <i>in vitro</i>

AIM: To work out the technique of saturation of the preserved amniotic membrane (AM) with platelet rich plasma (PRP) lysate and to evaluate the growth-stimulating effect of a combination of AM and PRP lysate in vitro. MATERIALS AND METHODS: In the experiment, AM samples preserved in 3 ways were used: silicate drying, lyophilization, cryopreservation. PRP lysate was prepared on the basis of volunteers blood. During the exposure of AM with PRP lysate, the optimal saturation time of canned AM with lysate was determined, the volume of lysate that 1 cm2 of AM could adsorb was estimated. The growth-stimulating effect of AM transplants was evaluated in the culture of human buccal epithelium. The dynamics of cell growth was evaluated after 1, 2 and 3 days from the moment of sowing. RESULTS: In the presence of PRP lysate, the mass of silicatedried AM increased 4.2 times, lyophilized AM 4.8 times, cryopreserved AM 1.8 times. AM samples obtained by lyophilization adsorbed PRP lysate most effectively. Five minutes of exposure with PRP lysate are enough to fully saturate the AM. AM without PRP lysate did not give a growth-stimulating effect. CONCLUSIONS: When comparing experiments with PRP lysate without AM and AM with PRP lysate, it was found that the greatest stimulation of cell growth occurred when using lyophilized AM and PRP lysate. Saturation of cryopreserved AM with PRP lysate was ineffective, and when using silicate-dried AM impregnated with PRP lysate, the greatest growth-stimulating effect was observed on the 1st day.

The biological effect of a combination of platelet lysate and amniotic membrane in buccal epithelium culture

Purpose: To study the biological effect of a combination of platelet lysate and amniotic membrane, preserved by various techniques, on human buccal epithelium culture. Materials and methods. Human amnion transplants were preserved using 3 methods: silicate drying, lyophilization, cryopreservation. The blood of healthy volunteers was used as a source of platelets. Platelet-rich plasma (PRP) with a platelet content over 1000 thousand/mcl and more was isolated from the donors blood, frozen at -80 °С and defrosted at 0–4 °С to prepare platelet lysate. Growth-stimulating effect of the amnion transplants was studied in different groups: control group 1 — without amnion and without PRP lysate; control group 2 — PRP lysate without amnion; experimental group 1 — amnion without PRP lysate; experimental group 2 — amnion samples combined with PRP lysate. The study was carried out on the example of human buccal epithelium culture of 3–5 passages. The dynamics of cell growth was evaluated after 1, 2 and 3 days from the moment of seeding. The number of cells and their viability were evaluated using original methods based on vital cell staining and their examination in a fluorescent microscope. Results. All samples of preserved amnions were non-toxic and did not damage the structural and functional characteristics of the buccal epithelium. On the other hand, the use of amnion without PRP lysate did not have a growth-stimulating effect on cells. Among the amnion samples combined with PRP lysate, the combination of lyophilized amnion and PRP lysate was the most effective during the entire study period. Conclusions. Silicate drying, lyophilization and cryopreservation of the amniotic membrane makes it possible to obtain biocompatible and non-toxic transplants, based on human amnion. Lyophilized amnions are the most optimal for saturating PRP lysate. The combination of lyophilized amnion and PRP lysate stimulates cell growth in vitro without violating their structural integrity.

Application of amniotic membranes in reconstructive surgery of internal organs-A systematic review and meta-analysis

Amniotic membrane (AM) has great potential as a scaffold for tissue regeneration in reconstructive surgery. To date, no systematic review of the literature has been performed for the applications of AM in wound closure of internal organs. Therefore, in this systematic review and meta-analysis, we summarize the literature on the safety and efficacy of AM for the closure of internal organs. A systematic search was performed in MEDLINE-PubMed database and OVID Embase to retrieve human and controlled animal studies on wound closure of internal organs. The Cochrane Risk of Bias tool for randomized clinical trials and the SYRCLE risk of bias tool for animal studies were used. Meta-analyses (MAs) were conducted for controlled animal studies to assess efficacy of closure, mortality and complications in subjects who underwent surgical wound closure in internal organs with the application of AM. Sixty references containing 26 human experiments and 36 animal experiments were included. The MAs of the controlled animal studies showed comparable results with regard to closure, mortality and complications, and suggested improved mechanical strength and lower inflammation scores after AM application when compared to standard surgical closure techniques. This systematic review and MAs demonstrate that the application of AM to promote wound healing of internal organs appears to be safe, efficacious, and feasible.

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.

Emerging tissue engineering strategies for the corneal regeneration

Cornea as the outermost layer of the eye is at risk of various genetic and environmental diseases that can damage the cornea and impair vision. Corneal transplantation is among the most applicable surgical procedures for repairing the defected tissue. However, the scarcity of healthy tissue donations as well as transplantation failure has remained as the biggest challenges in confront of corneal grafting. Therefore, alternative approaches based on stem-cell transplantation and classic regenerative medicine have been developed for corneal regeneration. In this review, the application and limitation of the recently-used advanced approaches for regeneration of cornea are discussed. Additionally, other emerging powerful techniques such as 5D printing as a new branch of scaffold-based technologies for construction of tissues other than the cornea are highlighted and suggested as alternatives for corneal reconstruction. The introduced novel techniques may have great potential for clinical applications in corneal repair including disease modeling, 3D pattern scheming, and personalized medicine.

Developing a pro-angiogenic placenta derived amniochorionic scaffold with two exposed basement membranes as substrates for cultivating endothelial cells

Decellularized and de-epithelialized placenta membranes have widely been used as scaffolds and grafts in tissue engineering and regenerative medicine. Exceptional pro-angiogenic and biomechanical properties and low immunogenicity have made the amniochorionic membrane a unique substrate which provides an enriched niche for cellular growth. Herein, an optimized combination of enzymatic solutions (based on streptokinase) with mechanical scrapping is used to remove the amniotic epithelium and chorion trophoblastic layer, which resulted in exposing the basement membranes of both sides without their separation and subsequent damages to the in-between spongy layer. Biomechanical and biodegradability properties, endothelial proliferation capacity, and in vivo pro-angiogenic capabilities of the substrate were also evaluated. Histological staining, immunohistochemistry (IHC) staining for collagen IV, and scanning electron microscope demonstrated that the underlying amniotic and chorionic basement membranes remained intact while the epithelial and trophoblastic layers were entirely removed without considerable damage to basement membranes. The biomechanical evaluation showed that the scaffold is suturable. Proliferation assay, real-time polymerase chain reaction for endothelial adhesion molecules, and IHC demonstrated that both side basement membranes could support the growth of endothelial cells without altering endothelial characteristics. The dorsal skinfold chamber animal model indicated that both side basement membranes could promote angiogenesis. This bi-sided substrate with two exposed surfaces for cultivating various cells would have potential applications in the skin, cardiac, vascularized composite allografts, and microvascular tissue engineering.

Efficacy of extracts from cryopreserved placenta on third-degree burns in rats

Human placenta extracts have anti-inflammatory, antioxidant and wound-healing properties, so they are promising drugs for the treatment of wounds of various origins, including burns. Cryopreservation methods are widely used to preserve the biological activity of placental drugs for a long time. The aim of this work was to study the effect of low-temperature storage of the placenta on the regenerative properties of its extracts. Fragments of freshly obtained placentas were cooled by immersion in liquid nitrogen and stored at –196 °C for 6 months. The placenta was warmed in a water bath at 37 °C. The effect of low-temperature preservation of the placenta on the ability of its extracts to positively affect the wound healing process was studied in a model of thermal burn of III B degree in rats. The effectiveness of wound treatment with extracts from cryopreserved placenta was evaluated by planimetric and histological methods at 3, 7, 14, 21 and 28 days after the burn. The activity of antioxidant enzymes in the serum of animals was also determined. superoxide dismutase activity was assessed by inhibition of adrenaline autooxidation in carbonate buffer, catalase activity was assessed by the degree of inhibition of ammonium peroxide formation. It has been shown that the treatment of burns with extracts from cryopreserved placenta helped to accelerate the regeneration processes and the rate of wound healing. The formation of granulation tissue was detected on the 7th day of treatment with extracts, and on the 14th day in the control. The area of burn wounds during treatment with extracts probably differed from the control starting from 14 days after application of the burn. It was found that the dynamics of recovery of catalase activity after burns is probably higher on the 7th day of treatment with extracts. The obtained data testify to the high efficiency of application of placenta stored at low-temperature for the purpose of obtaining extracts from it with preservation of regenerative properties.

Adipose-Derived Stromal Cells and Mineralized Extracellular Matrix Delivery by a Human Decellularized Amniotic Membrane in Periodontal Tissue Engineering

Periodontitis is a prevalent disease characterized by the loss of periodontal supporting tissues, bone, periodontal ligament, and cementum. The application of a bone tissue engineering strategy with Decellularized Human Amniotic Membrane (DAM) with adipose-derived stromal cells (ASCs) has shown to be convenient and valuable. This study aims to investigate the treatments of a rat periodontal furcation defect model with DAM, ASCs, and a mineralized extracellular matrix (ECM). Rat ASCs were expanded, cultivated on DAM, and with a bone differentiation medium for four weeks, deposited ECM on DAM. Periodontal healing for four weeks was evaluated by micro-computed tomography and histological analysis after treatments with DAM, ASCs, and ECM and compared to untreated defects on five consecutive horizontal levels, from gingival to apical. The results demonstrate that DAM preserves its structure during cultivation and healing periods, supporting cell attachment, permeation, bone deposition on DAM, and periodontal regeneration. DAM and DAM+ASCs enhance bone healing compared to the control on the gingival level. In conclusion, DAM with ASC or without cells and the ECM ensures bone tissue healing. The membrane supported neovascularization and promoted osteoconduction.

Polymeric membranes for biomedical applications

The rapid development of nanotechnology paved the way for further expansion of polymer chemistry and the fabrication of advanced polymeric membranes. Such modifications allowed enhancing or adding some unique properties, including mechanical strength, excellent biocompatibility, easily controlled degradability, and biological activity. This chapter discusses various applications of polymeric membranes in three significant areas of biomedicine, including tissue engineering, drug delivery systems, and diagnostics. It is intended to highlight here possible ways of improvement the properties of polymeric membranes, by modifying with other polymers, functional groups, compounds, drugs, bioactive components, and nanomaterials.

Antimicrobial Activity of Human Fetal Membranes: From Biological Function to Clinical Use

The fetal membranes provide a supportive environment for the growing embryo and later fetus. Due to their versatile properties, the use of fetal membranes in tissue engineering and regenerative medicine is increasing in recent years. Moreover, as microbial infections present a crucial complication in various treatments, their antimicrobial properties are gaining more attention. The antimicrobial peptides (AMPs) are secreted by cells from various perinatal derivatives, including human amnio-chorionic membrane (hACM), human amniotic membrane (hAM), and human chorionic membrane (hCM). By exhibiting antibacterial, antifungal, antiviral, and antiprotozoal activities and immunomodulatory activities, they contribute to ensuring a healthy pregnancy and preventing complications. Several research groups investigated the antimicrobial properties of hACM, hAM, and hCM and their derivatives. These studies advanced basic knowledge of antimicrobial properties of perinatal derivatives and also provided an important insight into the potential of utilizing their antimicrobial properties in a clinical setting. After surveying the studies presenting assays on antimicrobial activity of hACM, hAM, and hCM, we identified several considerations to be taken into account when planning future studies and eventual translation of fetal membranes and their derivatives as antimicrobial agents from bench to bedside. Namely, (1) the standardization of hACM, hAM, and hCM preparation to guarantee rigorous antimicrobial activity, (2) standardization of the antimicrobial susceptibility testing methods to enable comparison of results between various studies, (3) investigation of the antimicrobial properties of fetal membranes and their derivatives in the in vivo setting, and (4) designation of donor criteria that enable the optimal donor selection. By taking these considerations into account, future studies will provide crucial information that will enable reaching the optimal treatment outcomes using the fetal membranes and their derivatives as antimicrobial agents.

Applications of Human Amniotic Membrane for Tissue Engineering

An important component of tissue engineering (TE) is the supporting matrix upon which cells and tissues grow, also known as the scaffold. Scaffolds must easily integrate with host tissue and provide an excellent environment for cell growth and differentiation. Human amniotic membrane (hAM) is considered as a surgical waste without ethical issue, so it is a highly abundant, cost-effective, and readily available biomaterial. It has biocompatibility, low immunogenicity, adequate mechanical properties (permeability, stability, elasticity, flexibility, resorbability), and good cell adhesion. It exerts anti-inflammatory, antifibrotic, and antimutagenic properties and pain-relieving effects. It is also a source of growth factors, cytokines, and hAM cells with stem cell properties. This important source for scaffolding material has been widely studied and used in various areas of tissue repair: corneal repair, chronic wound treatment, genital reconstruction, tendon repair, microvascular reconstruction, nerve repair, and intraoral reconstruction. Depending on the targeted application, hAM has been used as a simple scaffold or seeded with various types of cells that are able to grow and differentiate. Thus, this natural biomaterial offers a wide range of applications in TE applications. Here, we review hAM properties as a biocompatible and degradable scaffold. Its use strategies (i.e., alone or combined with cells, cell seeding) and its degradation rate are also presented.