Human Amnion Membrane: Potential Applications in Oral and Periodontal Field

The Categorization of Perinatal Derivatives for Orthopedic Applications

Musculoskeletal (MSK) pathology encompasses an array of conditions that can cause anything from mild discomfort to permanent injury. Their prevalence and impact on disability have sparked interest in more effective treatments, particularly within orthopedics. As a result, the human placenta has come into focus within regenerative medicine as a perinatal derivative (PnD). These biologics are sourced from components of the placenta, each possessing a unique composition of collagens, proteins, and factors believed to aid in healing and regeneration. This review aims to explore the current literature on PnD biologics and their potential benefits for treating various MSK pathologies. We delve into different types of PnDs and their healing effects on muscles, tendons, bones, cartilage, ligaments, and nerves. Our discussions highlight the crucial role of immune modulation in the healing process for each condition. PnDs have been observed to influence the balance between anti- and pro-inflammatory factors and, in some cases, act as biologic scaffolds for tissue growth. Additionally, we assess the range of PnDs available, while also addressing gaps in our understanding, particularly regarding biologic processing methods. Although certain PnD biologics have varying levels of support in orthopedic literature, further clinical investigations are necessary to fully evaluate their impact on human patients.

Proteomic Characterization of Human Placenta: Insights into Potential Therapeutic Applications for Osteoarthritis

Biologics have become increasingly prominent as therapeutics in recent years due to their innate immune-privileged nature, biocompatibility, and high levels of protein biofactors. The aim of the study is to characterise the biologic, lyophilized human placenta (LHP) and explore its therapeutic potential for osteoarthritis (OA). The presence of six bioactive constituents that regulate cell-extracellular matrix interaction was identified by liquid chromatography coupled to electrospray ionization and quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF/MS). Metalloproteinase inhibitor 3 (TIMP3), alpha-1 anti-trypsin (a1AT), basic fibroblast growth factor (bFGF), and transforming growth factor β1 (TGFβ1) were detected and quantified using ELISA. The total protein content present in LHP by Bradford assay was found to be 409.35 ± 0.005 μg/ml. The analytical techniques such as Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR), solid state carbon-13 Nuclear Magnetic Resonance (ssC13 NMR) spectroscopy, and Differential Scanning Calorimetry (DSC) revealed the secondary structure and conformational stability of LHP. X-Ray diffraction (XRD) studies showed its amorphous nature. Bioactivity assessment of LHP was performed in human keratinocytes (HaCaT) and human dermal fibroblasts (HDF) by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The LHP was highly proliferative against skin cells and non-toxic, based on the findings of the bioactivity assay. LHP has the potential to be used as a therapeutic agent for OA, as its characterisation unveiled its physical stability, significant concentration of bioactive components that are pertinent to cartilage repair and its conformational stability.

Novel Functional Dressing Materials for Intraoral Wound Care

Intraoral wounds represent a particularly challenging category of mucosal and hard tissue injuries, characterized by the unique structures, complex environment, and distinctive healing processes within the oral cavity. They have a common occurrence yet frequently inflict significant inconvenience and pain on patients, causing a serious decline in the quality of life. A variety of novel functional dressings specifically designed for the moist and dynamic oral environment have been developed and realized accelerated and improved wound healing. Thoroughly analyzing and summarizing these materials is of paramount importance in enhancing the understanding and proficiently managing intraoral wounds. In this review, the particular processes and unique characteristics of intraoral wound healing are firstly described. Up-to-date knowledge of various forms, properties, and applications of existing products are then intensively discussed, which are categorized into animal products, plant extracts, natural polymers, and synthetic products. To conclude, this review presents a comprehensive framework of currently available functional intraoral wound dressings, with an aim to provoke inspiration of future studies to design more convenient and versatile materials.

Characterization of a full-thickness decellularized and lyophilized human placental membrane for clinical applications

Allografts derived from live-birth tissue obtained with donor consent have emerged as an important treatment option for wound and soft tissue repairs. Placental membrane derived from the amniotic sac consists of the amnion and chorion, the latter of which contains the trophoblast layer. For ease of cleaning and processing, these layers are often separated with or without re-lamination and the trophoblast layer is typically discarded, both of which can negatively affect the abundance of native biological factors and make the grafts difficult to handle. Thus, a full-thickness placental membrane that includes a fully-intact decellularized trophoblast layer was developed for homologous clinical use as a protective barrier and scaffold in soft tissue repairs. Here, we demonstrate that this full-thickness placental membrane is effectively decellularized while retaining native extracellular matrix (ECM) scaffold and biological factors, including the full trophoblast layer. Following processing, it is porous, biocompatible, supports cell proliferation in vitro, and retains its biomechanical strength and the ability to pass through a cannula without visible evidence of movement or damage. Finally, it was accepted as a natural scaffold in vivo with evidence of host-cell infiltration, angiogenesis, tissue remodelling, and structural layer retention for up to 10 weeks in a murine subcutaneous implant model.

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.

Recent trends and perspectives in reconstruction and regeneration of intra/extra-oral wounds using tissue-engineered oral mucosa equivalents

Many conditions, including cancer, trauma, and congenital anomalies, can damage the oral mucosa. Multiple cultures of oral mucosal cells have been used for biocompatibility tests and oral biology studies. In recent decades, the clinical translation of tissue-engineered products has progressed significantly in developing tangible therapies and inspiring advancements in medical science. However, the reconstruction of an intraoral mucosa defect remains a significant challenge. Despite the drawbacks of donor-site morbidity and limited tissue supply, the use of autologous oral mucosa remains the gold standard for oral mucosa reconstruction and repair. Tissue engineering offers a promising solution for repairing and reconstructing oral mucosa tissues. Cell- and scaffold-based tissue engineering approaches have been employed to treat various soft tissue defects, suggesting the potential clinical use of tissue-engineered oral mucosa (TEOMs). In this review, we first cover the recent trends in the reconstruction and regeneration of extra-/intra-oral wounds using TEOMs. Next, we describe the current status and challenges of TEOMs. Finally, future strategic approaches and potential technologies to support the advancement of TEOMs for clinical use are discussed.

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

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

Modulating Growth Factor Receptor Signaling to Promote Corneal Epithelial Homeostasis

The corneal epithelium is the first anatomical barrier between the environment and the cornea; it is critical for proper light refraction onto the retina and prevents pathogens (e.g., bacteria, viruses) from entering the immune-privileged eye. Trauma to the highly innervated corneal epithelium is extremely painful and if not resolved quickly or properly, can lead to infection and ultimately blindness. The healthy eye produces its own growth factors and is continuously bathed in tear fluid that contains these proteins and other nutrients to maintain the rapid turnover and homeostasis of the ocular surface. In this article, we review the roles of growth factors in corneal epithelial homeostasis and regeneration and some of the limitations to their use therapeutically.

The Preparation and Clinical Efficacy of Amnion-Derived Membranes: A Review

Biological tissues from various anatomical sources have been utilized for tissue transplantation and have developed into an important source of extracellular scaffolding material for regenerative medicine applications. Tissue scaffolds ideally integrate with host tissue and provide a homeostatic environment for cellular infiltration, growth, differentiation, and tissue resolution. The human amniotic membrane is considered an important source of scaffolding material due to its 3D structural architecture and function and as a source of growth factors and cytokines. This tissue source has been widely studied and used in various areas of tissue repair including intraoral reconstruction, corneal repair, tendon repair, microvascular reconstruction, nerve procedures, burns, and chronic wound treatment. The production of amniotic membrane allografts has not been standardized, resulting in a wide array of amniotic membrane products, including single, dual, and tri-layered products, such as amnion, chorion, amnion-chorion, amnion-amnion, and amnion-chorion-amnion allografts. Since these allografts are not processed using the same methods, they do not necessarily produce the same clinical responses. The aim of this review is to highlight the properties of different human allograft membranes, present the different processing and preservation methods, and discuss their use in tissue engineering and regenerative applications.

Biodegradability of Amniotic Membrane as Potential Scaffold for Periodontal Regeneration

Background In the periodontal regenerative procedure, the membrane used should possess good mechanical stability with suitable resorption time to allow restoration of the lost periodontium. Amniotic membrane (AM) has regenerative potential as a scaffold or barrier membrane due to its various beneficial properties. However, its degradation rate is not clearly reported. Methodology This study aimed to evaluate the resorption capacity of AM and its surface architecture after being subjected to hydrolytic degradation analysis in phosphate buffer solution (PBS). AM was cut into sizes of 10 × 10 mm2 for three replicates. The membranes were weighed before and at different time intervals (days 7, 14, 21, and 28) after immersion in PBS. The degradation rate was determined by the percentage of mean weight loss from the initial weight at different time intervals. The AM surface profile was observed under scanning electron microscopy (SEM) before and after 28 days of immersion. Results The result shows a 92% loss of weight over 28 days with the highest attained in the first seven days (67%), followed by 7%, 17%, and 1% after days 14, 21, and 28, respectively. SEM of the AM surface before the degradation test showed a polygonal shape forming a well-arranged mosaic pattern covered with microvilli. At day 28, the remaining AM appears as porous surface architecture, irregularly arranged fibers, and no microvilli seen. Conclusions This study demonstrated that over four weeks of degradation analysis, AM was not entirely degraded but had lost some of the microstructure. The biodegradability of AM should be further evaluated to elucidate its stability within adequate time parallel with the tissue healing process in periodontal tissue regeneration.

Human Acellular Amniotic Membrane as Skin Substitute and Biological Scaffold: A Review of Its Preparation, Preclinical Research, and Clinical Application

Human acellular amniotic membrane (HAAM) has emerged as a promising tool in the field of regenerative medicine, particularly for wound healing and tissue regeneration. HAAM provides a natural biological scaffold with low immunogenicity and good anti-infective and anti-scarring results. Despite its potential, the clinic application of HAAM faces challenges, particularly with respect to the preparation methods and its low mechanical strength. This review provides a comprehensive overview of HAAM, covering its preparation, sterilization, preclinical research, and clinical applications. This review also discusses promising decellularization and sterilization methods, such as Supercritical Carbon Dioxide (SC-CO2), and the need for further research into the regenerative mechanisms of HAAM. In addition, we discuss the potential of HAAM as a skin dressing and cell delivery system in preclinical research and clinical applications. Both the safety and effectiveness of HAAM have been validated by extensive research, which provides a robust foundation for its clinical application.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Comparison of Amnion Membrane and Hyaluronic Acid in Gingival Recession Coverage and Gain in Clinical Attachment Level following Coronally Advanced Flap Procedure-A Clinical Study

Background

Gingival recession is defined as the apical migration of gingival margin to the cementoenamel junction. Recently, amnion membrane, the third-generation membrane which is a placental-derived tissue, has been introduced.

Materials and Methods

Study included 45 subjects with age group of 20-60 years of both genders. Patients with Miller's Class I and Class II gingival recession were selected for the study. The progress was assessed at baseline one, three, and six months observation interval through clinical parameters RD, RW, PD, and CAL at the end of six months.

Results

Recession depths in the first, third, and sixth month were 1.82 ± 0.442, 1.31 ± 0.47 mm, and 0.91 ± 0.29, respectively, which showed a significant reduction from the baseline. Recession widths in the first, second, and third weeks were 3.04 ± 0.442 mm, 1.31 ± 0.47 mm, and 1.49 ± 0.59 mm, respectively. There was a statistically significant reduction (P > 0.005) when compared to the baseline. Pocket depths in the first, third, and sixth month were 0.93 ± 0.447, 0.42 ± 0.50, and 0.24 ± 0.43 (P > 0.005) which is significant when compared to baseline. Clinical attachment levels in the first, third, and sixth month were 2.73 ± 0.751, 1.78 ± 0.70, and 1.18 ± 0.53 (P > 0.005) which is significant compared to six months.

Conclusion

Within the limitations of the present study, the data obtained by periodic assessment of the clinical parameters indicate the use of amnion membrane and hyaluronic acid, and proper technique may thus be the panacea for root coverage procedure.

Surgical Reconstruction of Stage 3 and 4 Pressure Injuries: A Literature Review and Proposed Algorithm from an Interprofessional Working Group

OBJECTIVE

Stage 3 and 4 pressure injuries (PIs) present an enormous societal burden with no clearly defined interventions for surgical reconstruction. The authors sought to assess, via literature review and a reflection/evaluation of their own clinical practice experience (where applicable), the current limitations to the surgical intervention of stage 3 or 4 PIs and propose an algorithm for surgical reconstruction.

METHODS

An interprofessional working group convened to review and assess the scientific literature and propose an algorithm for clinical practice. Data compiled from the literature and a comparison of institutional management were used to develop an algorithm for the surgical reconstruction of stage 3 and 4 PIs with adjunctive use of negative-pressure wound therapy and bioscaffolds.

RESULTS

Surgical reconstruction of PI has relatively high complication rates. The use of negative-pressure wound therapy as adjunctive therapy is beneficial and widespread, leading to reduced dressing change frequency. The evidence for the use of bioscaffolds both in standard wound care and as an adjunct to surgical reconstruction of PI is limited. The proposed algorithm aims to reduce complications typically seen with this patient cohort and improve patient outcomes from surgical intervention.

CONCLUSIONS

The working group has proposed a surgical algorithm for stage 3 and 4 PI reconstruction. The algorithm will be validated and refined through additional clinical research.

Guide bone regeneration (GBR) reconstruction of extensive alveolar bone defect due to infected radicular cyst enucleation: 2 case reports

INTRODUCTION AND IMPORTANCE

Reconstruction of alveolar bone defects caused by radicular cysts is challenging for oral and maxillofacial surgeons.

CASE PRESENTATION

Two Indonesian females had similar complaint of swelling in the vestibule area of the right mandible. Panoramic radiography showed radiolucent lesions. Participants underwent guided bone regeneration (GBR) reconstruction, which used pericardium membrane in the first case and amnion membrane in the second case. Post-surgery condition showed an improved prognosis and histology showed a radicular cyst.

DISCUSSION

The use of pericardium membrane is easier compared to the amnion membrane, where success requires regular follow-up.

CONCLUSION

Alveolar bone defect reconstruction based on GBR requires meticulous preparation regarding patient condition, case selection and technical comprehension to ensure better treatment outcomes.

Developing small-diameter vascular grafts with human amniotic membrane: long-term evaluation of transplantation outcomes in a small animal model

While current clinical utilization of large vascular grafts for vascular transplantation is encouraging, tissue engineering of small grafts still faces numerous challenges. This study aims to investigate the feasibility of constructing a small vascular graft from decellularized amniotic membranes (DAMs). DAMs were rolled around a catheter and each of the resulting grafts was crosslinked with (a) 0.1% glutaraldehyde; (b) 1-ethyl-3-(3-dimethylaminopropyl) crbodiimidehydro-chloride (20 mM)-N-hydroxy-succinimide (10 mM); (c) 0.5% genipin; and (d) no-crosslinking, respectively. Our results demonstrated the feasibility of using a rolling technique followed by lyophilization to transform DAM into a vessel-like structure. The genipin-crosslinked DAM graft showed an improved integrated structure, prolonged stability, proper mechanical property, and superior biocompatibility. After transplantation in rat abdominal aorta, the genipin-crosslinked DAM graft remained patent up to 16 months, with both endothelial and smooth muscle cell regeneration, which suggests that the genipin-crosslinked DAM graft has great potential to beimplementedas a small tissue engineered graft for futurevasculartransplantation.

Feto-placental Unit: From Development to Function

The placenta is an intriguing organ that allows us to survive intrauterine life. This essential organ connects both mother and fetus and plays a crucial role in maternal and fetal well-being. This chapter presents an overview of the morphological and functional aspects of human placental development. First, we describe early human placental development and the characterization of the cell types found in the human placenta. Second, the human placenta from the second trimester to the term of gestation is reviewed, focusing on the morphology and specific pathologies that affect the placenta. Finally, we focus on the placenta's primary functions, such as oxygen and nutrient transport, and their importance for placental development.

Skin substitutes for the management of mohs micrographic surgery wounds: a systematic review

The data on skin substitute usage for managing Mohs micrographic surgery (MMS) wounds remain limited. This systematic review aimed to provide an overview of skin substitutes employed for MMS reconstruction, summarize clinical characteristics of patients undergoing skin substitute-based repair after MMS, and identify advantages and limitations of skin substitute implementation. A systematic review of Ovid MEDLINE, EMBASE, Cochrane Library, and Web of Science databases, from inception to April 7, 2021, identified all cases of MMS defects repaired using skin substitutes. A total of 687 patients were included. The mean patient age was 70 years (range: 6-98 years). Commonly used skin substitutes were porcine collagen (n = 397), bovine collagen (n = 78), Integra (n = 53), Hyalofill (n = 43), amnion/chorion-derived grafts (n = 40), and allogeneic epidermal-dermal composite grafts (n = 35). Common factors influencing skin substitute selection were cost, healing efficacy, cosmetic outcome, patient comfort, and ease of use. Some articles did not specify patient and wound characteristics. Skin substitute usage in MMS reconstruction is not well-guided. Blinded randomized control trials comparing the efficacy of skin substitutes and traditional repair methods are imperative for establishing evidence-based guidelines on skin substitute usage following MMS.

Standardized reporting of amnion and amnion/chorion allograft data for wound care

Background

The favorable biological and mechanical properties of the most common components of the placenta, the amnion and chorion, have been explored for regenerative medical indications. The use of the combination of amnion and chorion has also become very popular. But, published data from placental tissues in their final, useable form is lacking. During treatment with membrane product, the tissue is usually sterile, intact and laid on a wound or treatment area. The factors available to the treatment area from the applied product need to be elucidated and presented in a relatable form. Current reporting for eluted growth factor results are typically expressed per milliliter, which is not informative with respect to the area of tissue covered by the actual membrane and may differ among techniques.

Methods

To address this inconsistency, amnion or amnion/chorion were isolated from human placentas and processed by a proprietary procedure. The final dry, sterilized product was evaluated for structural components and growth factor elution. Growth factors were quantified by multiplex panels and ELISAs and the values normalized to specific area and elution volume of finished product. This information allows extrapolation to all membrane sizes and affords cross‐study comparisons.

Results

Analysis of membrane supernatants show that dehydrated, sterilized amnion and amnion/chorion elute factors that are conducive to wound healing, which are available to recipient tissues. Importantly, these measurable factors eluted from dehydrated, sterilized membranes can be reported as a function of available factors per square centimeter of tissue.

Conclusions

The standardized characterization of dehydrated, sterilized amnion and amnion/chorion as delivered to recipient tissues permits understanding and comparison of the products across various graft sizes, types, and eluate volumes. Further, reporting this data as a function of cm² of dehydrated tissue allows extrapolation by independent scientists and clinicians.

Mouse ovarian follicle growth in an amniotic membrane-based hydrogel

Three-dimensional cultures of follicles on ECM-based scaffolds can be an approach for women who become infertile after cancer treatments. Human amniotic membrane (HAM) is extensively employed in tissue engineering because of its unique properties. We cultured mouse pre-antral follicles in a hydrogel derived from decellularized amniotic membrane (DAM) combined with alginate (ALG) to improve ovarian follicle culture. HAM was decellularized. Quantitative (nuclear contents, collagen, glycosaminoglycan [GAG]) and qualitative (DAPI, H&E, Masson's trichrome, Alcian blue, scanning electron microscopy assessments were performed. Then, we created an amniotic membrane-based hydrogel (AMBH) and conducted AMBH characterization assays (rheology, MTS, degradation rate). Isolated mouse pre-antral follicles were cultured in 15 mg/mL AMBH (AMBH15), 30 mg/mL AMBH (AMBH30), or 45 mg/mL AMBH (AMBH45). ALG hydrogel was the control group. Follicular diameters, estradiol hormone secretion rate, follicular morphology, and the follicle antral and degeneration rate were examined. Quantitative and qualitative assays indicated successful decellularization. AMBH characterization assays showed that the ALG hydrogel had more appropriate gelation and slower degradation than AMBH. There was a statistically higher antral follicle formation rate in the AMBH45 group (p < .05) compared to the AMBH30 and AMBH15 groups and less (p < .05) degenerated follicles. There was no significant difference with the ALG group. Diameter and estradiol hormone secretion in the AMBH45 group were not significantly higher than the ALG group. Although decellularization was confirmed and the viscoelastic parameters of AMBH support follicle culture, there was no significant effect on ovarian follicle maturation compared to the ALG control group.

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.

Osteochondral regeneration in rabbit using xenograft decellularized ECM in combination with different biological products; platelet-rich fibrin, amniotic membrane extract, and mesenchymal stromal cells

This study aimed to investigate the regenerative effect of decellularized osteochondral ECM xenograft in combination with various biological products in an osteochondral (OC) defect. OC tissue from the sheep femur were obtained and decellularized. The decellularized ECM (dECM) was combined with either platelet-rich fibrin (PRF), amniotic membrane extract (AME), or rabbit bone marrow-derived mesenchymal stromal cells (rBMSCs). The hybrid dECM-biological products were then utilized for the treatment of rabbit OC critical size defects. The regenerative potential of different groups was compared using; MRI, macroscopic assessment, histopathology, and histomorphometry. All characterizations analysis verified successful decellularization. Three months post-surgery, macroscopic findings indicated that dECM was better compared to controls. Also, dECM in combination with AME, PRF, and rBMSCs showed enhanced OC regeneration compared to only dECM (AME: +100%, PRF: +61%, rBMSCs: +28%). In particular, the dECM+AME group results in the best integration of new cartilage into surrounding cartilage tissue. The histomorphometric evaluations demonstrated enhancement in new cartilage formation and bone tissue (86.5 ± 5.9% and 90 ± 7.7%, respectively) for the dECM+AME group compared to other groups. Furthermore, histological results for the dECM+AME elucidated a mature hyaline cartilage tissue that covered the new and symmetrically formed subchondral bone, exhibiting a significantly higher regenerative effect compared to all other treated groups. This finding was also confirmed with MRI images. The current study revealed that in addition to the benefits of dECM alone, its combination with AME indicated to have a superior regenerative effect on OC regeneration. Overall, dECM+AME may be considered a suitable construct for treating knee OC injuries.

Efficacy of Freeze-Dried Amnion Grafts on Cytokines in Uterine Exudates Following Hysteroscopic Adhesiolysis of Severe Intrauterine Adhesions

Background

Intrauterine adhesions (IUAs) are a benign uterine disorder that results in intrauterine adhesions and scarring. This study was conducted to assess the effects of freeze-dried amnion grafts on the concentrations of adhesion-related cytokines in uterine exudates following hysteroscopic adhesiolysis of IUAs.

Materials and Methods

This study was a prospective randomized controlled trial. Thirty patients who underwent hysteroscopic adhesiolysis for severe IUAs were enrolled. They were randomly divided into a study group (with freeze-dried amnion graft treatment after surgery, N = 15) and a control group (without a graft, N = 15). After complete separation of adhesions, a Foley balloon containing a freeze-dried amnion graft was inserted into the uterine cavity in the study group, while a Foley balloon with no graft was placed in the control group. Enzyme-linked immunosorbent assays were performed to test adhesion-related cytokine concentrations in uterine exudates, including IL-1β, TNF-α, and VEGF, at different time intervals after surgery. Second-look hysteroscopy was conducted three months after the surgery. On the basis of the American Fertility Society (AFS) scoring system, the level of adhesions was evaluated during hysteroscopy.

Results

The postoperative volume of the uterine exudates in the study group was significantly lower than that of the control group (P < 0.05). The adhesion-related cytokine concentrations of TNF-α, VEGF, and IL-1β significantly increased after surgery in both groups. Their concentrations were significantly lower in the study group than in the control group (P < 0.05). Moreover, IL-1β exhibited a long-lasting effect in the study group. AFS scores and readhesion rates were significantly lower in the study group than in the control group after hysteroscopic adhesiolysis of severe IUAs.

Conclusion

The application of freeze-dried amnion grafts is beneficial to the postoperative recovery of patients with severe IUAs and may reduce the readhesion rate after hysteroscopic adhesiolysis by lowering adhesion-related cytokines, including TNF-α, VEGF, and IL-1β.

Comparative evaluation of the efficacy of amniotic membrane with collagen membrane along with demineralized freeze-dried bone allograft in the treatment of periodontal intrabony defects – A clinico-radiographic study

Context:

The use of human-derived amniotic barrier membranes in regenerative procedures along with allograft like demineralized freeze-dried bone allograft (DFDBA) has displayed promising outcomes.

Aims:

The objective of the current research was to clinically and radiographically evaluate and compare amniotic membrane (AM) and collagen membrane (CM) in combination with open flap debridement (OFD) along with DFDBA in the management of human periodontal intrabony defects.

Settings and Design:

The present research-based study was a randomized controlled clinical trial of 6 months duration.

Materials and Methods:

A total of twenty chronic periodontitis patients with intrabony defects were randomly divided into two groups: Group 1 treated with OFD + DFDBA + AM and Group 2 with OFD + DFDBA + CM. Clinical parameters such as plaque index (PI), gingival index (GI), pocket probing depth (PPD), and relative attachment level were recorded and evaluated at baseline, 3 months, and 6 months. The relative intrabony defect component level (rIBD) was recorded at baseline and after 6 months employing a millimeter X-ray grid.

Statistical Analysis Used:

For comparison of clinical parameters and radiographic parameters at various intervals unpaired t-test, repeated measures ANOVA test, and paired t-test were used. The P value was taken statistically significant when less than 0.05 (P < 0.05).

Results:

A statistically significant difference in PI, GI, PPD, and RAL for both the groups were found on intragroup comparison between baseline, 3 months, and 6 months (P < 0.05). On intragroup comparison, the difference in mean rIBD was statistically significant from baseline to 6 months. However, for all the clinical and radiographic parameters, no statistically significant difference was noted between both the groups (P > 0.05).

Conclusions:

In the treatment of intrabony defects AM being an allograft can be considered an alternative novel membrane for regenerative procedures.

Human amniotic membrane extracellular matrix scaffold for dental pulp regeneration in vitro and in vivo

AIM

In order to obtain a 3-dimentional scaffold with predictable clinical results for pulp regeneration, this study aims to fabricate and characterize a porous decellularized human amniotic membrane (HAM) extracellular matrix (ECM) scaffold, and evaluate its potential to promote pulp regeneration in vitro and in vivo.

METHODOLOGY

The HAM was decellularized, and its histology and DNA content were analysed to confirm decellularization. The scaffolds were synthesized with 15, 22.5 and 30 mg/ml concentrations. The porosity, pore size, phosphate-buffered saline (PBS) absorption and degradation rate of the scaffolds were assessed. In vitro experiments were performed on human dental pulp stem cells (hDPSCs) to assess their viability, proliferation, adhesion and migration on the scaffolds. The optimal group was selected for in vivo immunogenicity assessment and was also used as the cell-free or cell-loaded scaffold in root segment models to evaluate pulp regeneration. All nonparametric data were analysed with the Kruskal-Wallis test followed by Dunn's post hoc test, whilst quantitative data were analysed with one-way anova.

RESULTS

Decellularization of HAM was confirmed (p < .05). The porosity of all scaffolds was more than 95%, and the pore size decreased with an increase in ECM concentration (p < .01). PBS absorption was not significantly different amongst the groups, whilst 30 mg/ml ECM scaffold had the highest degradation rate (p < .01). The hDPSCs adhered to the scaffold, whilst their proliferation rate increased over time in all groups (p < .001). Cell migration was higher in 30 mg/ml ECM scaffold (p < .05). In vivo investigation with 30 mg/ml ECM scaffold revealed mild to moderate inflammatory response. In root segments, both cell-free and cell-loaded 30 mg/ml scaffolds were replaced with newly formed, pulp-like tissue with no significant difference between groups. Immunohistochemical assessments revealed high revascularization and collagen content with no significant difference amongst the groups.

CONCLUSION

The 30 mg/ml HAM ECM scaffold had optimal physical properties and better supported hDPSC migration. The HAM ECM scaffold did not interfere with formation of pulp-like tissue and revascularization within the root canal when employed as both cell-free and cell-loaded scaffold. These results highlight the potential of HAM ECM membrane for further investigations in regenerative endodontics.

Using of Amniotic Membrane Derivatives for the Treatment of Chronic Wounds

Amniotic membrane grafts have some therapeutic potential for wounds healing. Early application of amniotic membrane turned out as beneficial in healing ulcers, burns, and dermal injuries. Since the second half of the 20th century, the autotransplants of amniotic/chorion tissue have been also used for the treatment of chronic neuropathic wounds, cornea surface injuries, pterygium and conjunctivochalasis, and dental and neurosurgical applications. The aim of this publication is to prepare a coherent overview of amniotic membrane derivatives use in the field of wound healing and also its efficacy. In total 60 publications and 39 posters from 2000-2020 were examined. In these examined publications of case studies with known study results was an assemblage of 1141 patients, and from this assemblage 977 were successfully cured. In case of posters, the assemblage is 570 patients and 513 successfully cured. From the investigated data it is clear that the treatment efficacy is very high-86% and 90%, respectively. Based on this information the use of the amniotic membrane for chronic wounds can be considered highly effective.

Chorion and amnion/chorion membranes in oral and periodontal surgery: A systematic review

The aim of this study was to perform a systematic review on the clinical applications where chorion membrane (CM) and amnion/chorion membrane (ACM) were used for oral tissue regeneration procedures. Selection of articles was carried out by two evaluators in Pubmed and Scopus databases, and Outcomes (PICO) method was used to select the relevant articles. Clinical studies reporting the use of CM or ACM for oral soft and hard tissue regeneration were included. The research involved 21 studies conducted on 375 human patients. Seven clinical applications of CM and ACM in oral and periodontal surgery were identified: gingival recession treatment, intrabony and furcation defect treatment, alveolar ridge preservation, keratinized gum width augmentation around dental implants, maxillary sinus membrane repair, and large bone defect reconstruction. CM and ACM were compared to negative controls (conventional surgeries without membrane) or to the following materials: collagen membranes, dense polytetrafluoroethylene membranes, platelet-rich fibrin membranes, amnion membranes, and to a bone substitute. Several studies support the use of CM and ACM as an efficient alternative to current techniques for periodontal and oral soft tissue regeneration procedures. However, further studies are necessary to increase the level of evidence and especially to demonstrate their role for bone regeneration.

Case Report: Freeze-Dried Human Amniotic Membrane Allograft for the Treatment of Chronic Wounds: Results of a Multicentre Observational Study

An inability of the human body to heal acute wounds under certain conditions results in the formation of chronic ulcers. Chronic wounds not only cause significant pain and discomfort for patients but also serve as an entry for microorganisms into the human body, which can result in serious life-threatening problems and become a significant burden for the patients and society. The current work present results of a multicentre prospective observational study demonstrating the use of a lyophilized amniotic membrane (AM) in the treatment of chronic wounds (various etiologies). Lyophilized AM produced under the commercial brand Amnioderm® was used as an allograft material for therapy of chronic wounds, in addition to chronic ulcer standard-of-care (SoC) protocols. The duration of wounds considered for the application of AM ranged between 2 months and 11 years. In total, 16 patients were enrolled to the study, of which eight were completely healed, six demonstrated a significantly reduced ulcer size, and two did not respond to the AM therapy. The current study unambiguously demonstrates an effective alternative to the standard of chronic wound care and confirms a significant effect of the AM application for chronic wound management as a new SoC.

Photo-crosslinkable amniotic membrane hydrogel for skin defect healing

The human amniotic membrane (HAM) collagen matrix derived from human placenta can be decellularized (dHAM) to form a natural biocompatible material. dHAM has different bioactive substances and has been used widely in human tissue engineering research. However, dHAM has some disadvantages, e.g., poor mechanical properties, easy degradation and inconvenient operation and use, so it is not conducive to large-area or full-thickness skin defect healing. To overcome these limitations, for the first time, dHAM was grafted with methacrylic anhydride (MA) to form photocrosslinked dHAM methacrylate (dHAMMA); dHAMMA was then blended with methacrylated gelatin (GelMA), followed by the addition of a photosensitizer for photocrosslinking to obtain the fast-forming GelMA-dHAMMA composite hydrogel. Further, GelMA-dHAMMA was found to have the porous structure of a bicomponent polymer network and good physical and chemical properties. In vitro experiments, GelMA-dHAMMA was found to promote fibroblast proliferation and α-smooth muscle actin (α-SMA) expression. In vivo investigations also demonstrated that GelMA-dHAMMA promotes wound collagen deposition and angiogenesis, and accelerates tissue healing. GelMA-dHAMMA inherits the good mechanical properties of GelMA and maintains the biological activity of the amniotic membrane, promoting the reconstruction and regeneration of skin wounds. Thus, GelMA-dHAMMA can serve as a promising biomaterial in skin tissue engineering. STATEMENT OF SIGNIFICANCE: Since the early 20th century, the human amniotic membrane (HAM) has been successfully used for trauma treatment and reconstruction purposes. dHAM has different bioactive substances and has been used widely in human tissue-engineering research. In this work, the dHAM and gelatin were grafted and modified by using methacrylic anhydride (MA) to form photocrosslinked dHAMMA and methacrylated gelatin (GelMA). Then, the dHAMMA and GelMA were blended with a photosensitizer to form the GelMA-dHAMMA composite hydrogel derived from gelatin-dHAM. GelMA-dHAMMA exhibits a bicomponent-network (BCN) interpenetrating structure. dHAM dydrogel has advantages, e.g., good mechanical properties, slow degradation and convenient operation, so it is conducive to large-area or full-thickness skin defect healing.

A novel regenerative endodontic procedure in a traumatized immature tooth using amniotic membrane

Tooth nonvitality is one of the frequently seen consequences of dental trauma that causes the arrest of root development. Amniotic membrane has received a lot of attention for its use in transplantation and regeneration procedures. This article reports a unique and novel case of successful regenerative endodontic procedure done using amniotic membrane in a traumatized immature right maxillary central incisor of an 8-year-old girl. The clinical and radiographic evaluation done during the recall visits at 1, 3, 6, 9 and 12 months showed a progressive root growth with apical closure.

Amnion and collagen-based blended hydrogel improves burn healing efficacy on a rat skin wound model in the presence of wound dressing biomembrane

BACKGROUND

A burn wound is one of the most frequent and devastating injuries for patients which requires extensive care. Early treatment of burn wounds improves healing significantly.

OBJECTIVE

This study was designed to investigate the efficacy of amnion and collagen-based hydrogels on cutaneous burn wound healing in rats with covering membrane.

METHODS

We prepared a novel cell free hydrogel comprising human amnion, rabbit collagen, carboxymethyl cellulose sodium salt, citric acid, methyl paraben, propyl paraben, glycerin and triethanol amine. The wound covering membrane was developed from rabbit collagen and prawn shell chitosan. Beside swelling ratio, water absorption, equilibrium water content, gel fraction and spreadability analysis, in vitro cytotoxicity and biocompatibility tests were performed for the formulated hydrogels. Following the skin irritation study, second-degree burns were created on the dorsal region of the rats and the gels were applied with/without covering membrane to study the wound contraction and re-epithelialization period.

RESULTS

The formulated hydrogels were observed non-cytotoxic and compatible with human blood cells. No erythema and edema were found in skin irritation assay confirming the safety and applicability. Hydrogel consisting in a combination of amnion and collagen demonstrated significantly rapid wound healing, driven by complete re-epithelialization (16.75 ± 0.96 days) and closure by wound contraction (72 ± 3.27%, P < 0.0000009) when wound dressing membrane was used, whereas this gel alone healed about 62.5 ± 4.43% (P < 0.00001) and required 18.75 ± 0.50 days to complete re-epithelialization. Additionally, the gel with covering membrane treated group had maximum average body weight, food and water intake.

CONCLUSION

The amnion and collagen-based blended gel offers alternative possibilities to treat skin wounds when covered with film, which could overcome the limitations associated with modern therapeutic products such as high costs, long manufacturing times, complexities, storing, and presence of living biomaterials.

A Review on Modifications of Amniotic Membrane for Biomedical Applications

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

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

Due to the increasing number of studies performed in the field of regenerative medicine during the last two decades, more analytic studies are still needed to clarify the future prospect of this area of science. The main aim of this research was to review the clinical applications of human Amniotic membrane in the field of regenerative medicine critically. Furthermore, in the light of increasing numbers of available products derived from amniotic membrane, we aimed look in depth to see whether regenerative medicine research strategies have a place in the clinical setting. More specifically, in the present study, we attempted to provide insight on developing the new indication for more research and in the next step, for market leaders companies to expand cost-effectiveness of new derived AM products. 20 companies or distributers have offered some commercial products in this field. Survey on more than 90 clinical trials in last five years showed dermatology (and more specific wound healing), orthopedic, and ophthalmology are heavily biased toward multibillion dollar industry. Moreover, urology and dentistry with fewer numbers of clinical data in comparison with the above-mentioned areas, currently are in the path of translation (especially dentistry). In addition, otolaryngology and oncology with the lowest number showed more potential of research thorough understanding the properties that will help guiding the use of AM-derived products in these two areas in future. More than 50% of clinical studies were done or are developing in USA, which have the biggest share in market products. Subsequently, China, Egypt, India, Iran, and Germany with the ongoing clinical trials in different phases may have more approved products in near future.

Bilaminar Technique with Coronally Advanced Flap and Cryopreserved Human Amniotic Membrane in the Treatment of Gingival Recessions

Gingival recessions are usually treated with surgical therapies which involve the use of connective tissue autograft in order to thicken the gingival tissue. This has an important biological repercussion on patients since they will have surgical wounds in two different oral cavity sites. In this case report, we offer an alternative technique for the treatment of a Miller class I gingival recession. A 40-year-old female patient has been treated with a combination of bilaminar and coronally advance flap techniques to cover a Miller class I gingival recession with addition of cryopreserved human amniotic membrane. The human amniotic membrane has been employed to thicken the keratinized tissue. The human amniotic membrane in combination with bilaminar and coronally advance flap techniques has produced aesthetically and functionally satisfying results, covering completely the gingival recession and restoring the natural colour and thickness of the gingiva. Bilaminar technique with coronally advanced flap and cryopreserved human amniotic membrane is a valid alternative in treating Miller class I and II gingival recessions and reduce the biological morbidity of a double intervention.

Intermediate layer contribution in placental membrane allografts

Placental membrane (PM) allografts are commonly used to treat chronic wounds. Native PM is composed of an amnion, chorion, and intermediate layer (IL) that contain matrix structures and regulatory components beneficial in wound healing. Historically, commercially available allografts were composed of only one or two layers of the PM. To maximize the conserved material in PM allografts, a dehydrated complete human placental membrane (dCHPM) allograft processed using the Clearify™ process was developed. Histological and proteomic characterization comparing dCHPM allografts with native PM demonstrated that the majority of matrix structures and regulatory proteins are retained in dCHPM allografts through processing. To evaluate the importance of maintaining the entire intact PM and the contribution of the IL, the structural and proteomic makeup of the IL was compared with that of dCHPM allografts. This is the first known characterization of regulatory proteins in the IL. Results demonstrate that the IL contains over 900 regulatory and signaling components, including chemokines, growth factors, interleukins, and protease inhibitors. These components are key regulators of angiogenesis, neurogenesis, osteogenesis, inflammation, tissue remodeling, and host defense. The results show that the proteomic composition of the IL is consistent with that of the entire dCHPM allograft. Although further investigation is required to fully understand the contribution of the IL in PM allografts, these results demonstrate that the IL contains structural and regulatory proteins that can enhance the barrier and wound healing properties of PM allografts.

Effects of Amniotic Membrane Extract on the Hyperplastic Response of the Middle Ear Mucosa in a Bacterially-Induced Otitis Media Rat Model: A Preliminary Study

Objectives

Human amniotic membrane extract (AME) is known to contain numerous bioactive factors and anti-inflammatory substances. However, the anti-inflammatory effects of AME on the middle ear (ME) mucosa are unclear. This study assessed the effects of AME on the growth of the ME mucosa in response to bacterially-induced otitis media (OM).

Methods

OM was induced by inoculating nontypeable Haemophilus influenzae (NTHi) into the ME cavity of rats. ME mucosal explants were cultured in AME concentrations of 0, 5, 10, or 50 μg/mL. The area of explant outgrowth was measured in culture and analyzed at 1, 3, 5, and 7 days after explantation. The expression of Ki-67, mucin 5AC (MUC5AC), tumor necrosis factor-α (TNF-α), and interleukin-10 (IL-10) in the explants was also evaluated using quantitative polymerase chain reaction (PCR) and immunocytochemistry (ICC).

Results

The NTHi-induced ME mucosa growth increased gradually over the 7-day culture period in all explants at different AME concentrations. There was a trend for mucosal growth inhibition at higher concentrations of AME, although the growth was not significantly different among the groups until day 5. The ME mucosal explants treated with the 50 μg/mL concentration of AME showed significantly suppressed growth on postexplantation day 7 compared with other explants on the same day. PCR and ICC staining revealed that the expression of Ki-67, MUC5AC, TNF-α, and IL-10 further decreased in the explants with higher concentrations of AME than in those with lower concentrations of AME.

Conclusion

Our results showed that higher concentrations of AME reduced the mucosal proliferative response in bacterial OM in rats. These findings provide evidence that AME has an influence on the inflammatory and proliferative responses to NTHi infection in ME mucosa.

Comparison of amniotic membrane transplantation and carpal tunnel syndrome release surgery (CTRS) and CTRS alone: Clinical outcomes at 1-year follow-up

Carpal tunnel syndrome (CTS) is the most common focal entrapment mononeuropathy, comprising medium nerve chronic inflammation and fibrosis. Although carpal tunnel release surgery (CTRS) has demonstrated to be effective, around 3% to 25% of CTRS show recurrence. Amniotic membrane transplantation (AMT) has been used in different pathologies inhibiting inflammation and fibrosis and promoting nerve repair. The aim of this study was to determine the efficacy of AMT in CTRS. The present study comprised a randomized, single-blind controlled trial to compare the 1-year follow-up outcomes of AMT in CTRS (AMT group) or CTRS alone (control group) in patients with CTS. Thirty-five patients with unilateral or bilateral CTS were enrolled, and 47 wrists were randomized into two groups: the AMT group and the control group. To compare the outcomes, three different questionnaires scores (Boston Carpal Tunnel Syndrome Questionnaire, Disabilities of the Arm, Shoulder, and Hand, and Historical-Objective scale) were used. Evaluations were assessed at baseline and at 15 days, 1, 3, 6, and 12 months after surgery. Compared with the control group, the AMT group showed significant (p < 0.05) reductions in all scores from 6 months after surgery until the end of the study. Both AMT and control groups showed significant intragroup differences in all scores, since the first month after surgery until the end of the study in comparison with the baseline scores. Taken together, these results indicate that CTRS in conjunction with AMT is more effective than CTRS alone in patients with CTS at 1-year follow-up. Clinical Trial: NCT04075357; Amniotic Membrane in Carpal Tunnel Syndrome.

The biological mechanism involved in anticancer properties of amniotic membrane

The main role of amniotic membrane (AM), or amnion, is to protect the fetus from drying out and create an appropriate environment for its growth. AM is also a suitable candidate for the treatment of various diseases due to its unique characteristics. In recent years, a new line of research has focused on the anticancer properties of amnion and its potential use in cancer treatment. The in vitro and in vivo studies indicate the anti-proliferative and proapoptotic activities, as well as the angioregulatory and immunomodulatory properties of the amniotic membrane. However, the exact mechanism and molecular basis of these anticancer effects of AM are not fully elucidated. This paper presents an overview of the latest findings and knowledge about the anticancer effects of AM and its underlying molecular mechanisms, which is crucial for the application of amnion in cancer therapy.

Burn injury

Burn injuries are under-appreciated injuries that are associated with substantial morbidity and mortality. Burn injuries, particularly severe burns, are accompanied by an immune and inflammatory response, metabolic changes and distributive shock that can be challenging to manage and can lead to multiple organ failure. Of great importance is that the injury affects not only the physical health, but also the mental health and quality of life of the patient. Accordingly, patients with burn injury cannot be considered recovered when the wounds have healed; instead, burn injury leads to long-term profound alterations that must be addressed to optimize quality of life. Burn care providers are, therefore, faced with a plethora of challenges including acute and critical care management, long-term care and rehabilitation. The aim of this Primer is not only to give an overview and update about burn care, but also to raise awareness of the ongoing challenges and stigmata associated with burn injuries.

Skin substitutes for acute and chronic wound healing: an updated review

Background: Skin substitutes are designed to accelerate wound healing by providing replacement of extracellular matrix and can be used to promote healing of both acute and chronic wounds.Aim: To describe advantages, disadvantages, and indications for different skin substitutes with the intention of providing a systematic framework that clinicians can easily utilize in clinical practice.Materials and method: We conducted a PubMed, Cochrane Library, and company website search for publications using various search terms associated with skin substitutes.Results: Skin substitutes can be categorized as epidermal, dermal, and composite, depending on the skin component they contain, and further split into different categories depending on their composition and source of material, including xenograft, acellular allograft, cellular allograft, autograft, and synthetic skin substitutes. Because there is no ideal option for skin substitutes that meet all the criteria for optimal wound healing, there is ongoing research evaluating and developing different skin substitute options.Conclusion: Our model of skin substitutes was organized based on the different layers of cutaneous involvement and the origin of the product material. We believe that this framework provides a practical guide for selection of the most appropriate skin substitute based on clinical indication.

The effects of cryopreserved human amniotic membrane on fracture healing: Animal study

Objective

The aim of this study was to investigate the effects of human amniotic membrane (HAM) on fracture healing in an animal model.

Methods

Standard tibial diaphysial fractures were created in twenty-eight Wistar-Albino rats and treated with intramedullary Kirschner wire (K-wire) and HAM (HAM (+) group) or K-wire only (HAM (–) group). Fracture healing was evaluated by histological analysis, radiologic X-ray views and callus diameter measurements at 3rd and 6th weeks postoperatively.

Results

Fracture healing was histologically better in the HAM (+) group and the difference was statistically significant at both 3rd and 6th weeks postoperatively (p < 0.05). The highest histologic scores and entire woven bone formation (Huo Stage 8–9) were obtained at 6th weeks postoperatively in the HAM (+) group. Histological examination also revealed predominant fibrous tissue and partial cartilage formation (Huo Stage 2) at the postoperative 3rd week in the HAM (-) group. Equal amounts of woven bone and cartilage formation (Huo Stage 6–7) were observed at 3rd weeks postoperatively in the HAM (+) group and at 6th weeks postoperatively in the HAM (-) group. The callus diameters were greater in the HAM (+) group and the difference was statistically significant (p < 0.05) at 3rd and 6th weeks postoperatively. Although there was only a statistically significant difference (p < 0.05) at the postoperative 3rd week, radiological scores tended to be higher in the HAM (+) group at both the 3rd and 6th weeks postoperatively.

Conclusion

HAM is a cheap and easily accessible alternative biological material. HAM may be used to support surgical treatment of fractures, particularly where bone healing is expected to last longer.

Antifibrotic effects of total or partial application of amniotic membrane in hepatic fibrosis

Liver fibrosis is the final common pathway of chronic liver diseases, having cirrhosis as a possible progression, which has liver transplantation as the only effective treatment. Human amniotic membrane represents a potential strategy as a therapy for liver fibrosis, due to its anti-inflammatory, anti-fibrotic and immunomodulatory properties. The aim of this study was to evaluate amniotic membrane effects as a treatment for hepatic fibrosis induced in rats by bile duct ligation (BDL), verifying alterations between two different forms of amniotic membrane application, around all the lobes of the liver and around only one lobe of the liver. Two weeks after inducing fibrosis, an amniotic membrane fragment was applied to the surface of the liver, covering it either totally or partially. Four weeks later, the animals were euthanized and liver samples were collected. Histopathological and quantitative analyses demonstrated fibrosis severity decrease and an extremely significant reduction in the deposition of collagen in the groups treated with amniotic membrane, particularly when the amniotic membrane was applied in only one liver lobe. It is concluded that the amniotic membrane acted on the repair of liver fibrosis in both modes of application, with the application of the amniotic membrane around only one hepatic lobe being more effective in reducing the severity / extent of fibrosis.

Vascular tissue engineering: Fabrication and characterization of acetylsalicylic acid-loaded electrospun scaffolds coated with amniotic membrane lysate

As the incidence of small-diameter vascular graft (SDVG) occlusion is considerably high, a great amount of research is focused on constructing a more biocompatible graft. The absence of a biocompatible surface in the lumen of the engineered grafts that can support confluent lining with endothelial cells (ECs) can cause thrombosis and graft failure. Blood clot formation is mainly because of the lack of an integrated endothelium. The most effective approach to combat this problem would be using natural extracellular matrix constituents as a mimic of endothelial basement membrane along with applying anticoagulant agents to provide local antithrombotic effects. In this study, we fabricated aligned and random electrospun poly-L-lactic acid (PLLA) scaffolds containing acetylsalicylic acid (ASA) as the anticoagulation agent and surface coated them with amniotic membrane (AM) lysate. Vascular scaffolds were structurally and mechanically characterized and assessed for cyto- and hemocompatibility and their ability to support endothelial differentiation was examined. All the scaffolds showed appropriate tensile strength as expected for vascular grafts. Lack of cytotoxicity, cellular attachment, growth, and infiltration were proved using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and scanning electron microscopy. The blood compatibilities of different scaffolds examined by in vitro hemolysis and blood coagulation assays elucidated the excellent hemocompatibility of our novel AM-coated ASA-loaded nanofibers. Drug-loaded scaffolds showed a sustained release profile of ASA in 7 days. AM-coated electrospun PLLA fibers showed enhanced cytocompatibility for human umbilical vein ECs, making a confluent endothelial-like lining. In addition, AM lysate-coated ASA-PLLA-aligned scaffold proved to support endothelial differentiation of Wharton's jelly-derived mesenchymal stem cells. Our results together indicated that AM lysate-coated ASA releasing scaffolds have promising potentials for development of a biocompatible SDVG.

An investigational study of a dual-layer, chorion-free amnion patch as a protective barrier following lumbar laminectomy in a sheep model

The inherent properties of the human amniotic membrane (HAM) suggest its potential for use as a physical barrier during surgery to protect neural elements and vessels from the surrounding environment. The objective of this study was to evaluate the effect of a dual-layer, chorion-free amnion patch (DLAM; ViaShield®, Globus Medical Inc., Audubon, PA, USA) processed from HAM as a protective barrier following lumbar laminectomy in a sheep model. A multiplex immunoassay was performed to quantify the inherent cytokines present in the amnion after processing. Twelve skeletally mature female crossbred Suffolk sheep were randomly divided into two equal post-operative periods (4 and 10 weeks). Each sheep underwent a laminectomy at L3 and L5, and one of the surgical sites randomly received the DLAM treatment. At each postsurgical time point, the extent of epidural fibrosis and neurohistopathological responses at the laminectomy sites was assessed based on epidural fibrosis-dura tenacity scores and decalcified histology, respectively. Immunoassay results showed that inflammatory mediators and immunomodulatory cytokines were present in the amnion after processing, but no proangiogenic cytokines were detected. At 10 weeks, tissue tenacity was significantly less in the DLAM treatment group when compared with the operative control (1.2 ± 0.4 vs. 2.8 ± 0.4, p < 0.05), demonstrating the ability of DLAM to act as a barrier and cover the dura. Gross observations showed fewer fibroblasts in the DLAM group in comparison with the control at both post-operative time points. Fibroblast infiltration analysis indicated that at both 4 and 10 weeks, there were significantly more infiltrated fibroblasts in the operative control sites than in the DLAM-treated sites, expressed as a percentage of the total number of fibroblasts present (4 weeks: 72.3 ± 10.2% vs. 10.8 ± 10.1%, p < .05; 10 weeks: 84.9 ± 15.8% vs. 43.1 ± 11.6%, p < .05). Additionally, fibroblasts travelled further into the dura in the operative control group compared with the DLAM-treated group at both time points. In conclusion, this study found that DLAM reduced fibroblast infiltration and tissue tenacity following lumbar laminectomy in a sheep animal model. These findings support the potential use of DLAM in clinical practice as a protective barrier for neural elements and anterior vessels.

Cartography of the mechanical properties of the human amniotic membrane

Because of its low immunogenicity, biological properties, and high availability, the Human Amniotic Membrane (HAM) is widely used in the clinic and in tissue engineering research. However, while its biological characteristics are well described, its mechanical properties remain understudied especially in terms of inter- and intra-HAM variability. To guide bioengineers in the use of this natural biomaterial, a detailed cartography of the HAM's mechanical properties was performed. Maximal force (Fmax) and strain at break (Smax) were identified as the relevant mechanical criteria for this study after a combined analysis of histological sections, thickness measurements after dehydration, and uniaxial tensile tests. Eight HAMs were studied by mechanical cartography using a standardized cutting protocol and sampling pattern. On average, 103 ± 10 samples were retrieved and tested per HAM. Intra-tissue variability highlighted the fact that there were two mechanically distinct areas (placental and peripheral) in each HAM. For all HAMs, placental HAM was significantly stronger by 82 ± 45% and more stretchable by 19 ± 6% than their peripheral counterparts. Our results also demonstrated that placental, but not peripheral, HAM presented isotropic mechanical properties. Thus, placental HAM can be a raw material of choice that could be favored especially in the development of tissue engineering products where mechanical properties play a key role.

Temporomandibular Joint Discectomy Followed by Disc Replacement Using Viable Osteochondral and Umbilical Cord Allografts Results in Improved Patient Outcomes

PURPOSE

The ideal surgical solution to reconstruct the temporomandibular joint (TMJ) disc after it has been removed has remained elusive. The major obstacle has been identifying a durable biocompatible material that will provide for restoration of TMJ function. The present study evaluated the outcomes of the interpositional implantation of a cryopreserved viable osteochondral allograft (CVOCA) combined with a viable cryopreserved umbilical cord tissue (vCUT) allograft after TMJ discectomy in patients with internal derangement and/or degenerative joint disease (DJD).

PATIENTS AND METHODS

We implemented a retrospective case series study and enrolled patients with DJD or disc displacement diagnosed using the Diagnostic Criteria of Temporomandibular Disorders, who had undergone interpositional CVOCA and vCUT implantation after TMJ discectomy. The primary outcome variable was pain, measured using a visual analog scale (VAS). The secondary outcomes variables included maximal incisal opening (MIO) and Glasgow Benefit Inventory (GBI) general subscale scores. The primary analysis compared the preoperative measures with those at the last follow-up visit. Descriptive and analytic statistics were computed to summarize the sample's characteristics and assess the pre- and postoperative differences.

RESULTS

The study sample included 9 patients with a mean age of 36 years, and 44% were men. The VAS scores had decreased significantly from 9.0 ± 2.0 to 3.0 ± 3.0 postoperatively (P = .001). The MIO had increased from 31 ± 5 to 36 ± 5 mm (P = .178). The average GBI general subscale score of 13 ± 46 for the 9 patients showed a trend toward improved quality of life and patient satisfaction with the surgery. The median postoperative follow-up at the time of our report was 15 months (interquartile range, 10; range, 2 to 27) without treatment-related complications.

CONCLUSIONS

The reported outcomes suggest that the interpositional implantation of CVOCA and vCUT after TMJ discectomy could be a solution for reducing TMJ-related pain and restoring TMJ function. Longer follow-up and prospective multicenter studies are warranted.

Application of amniotic membrane in reconstructive urology; the promising biomaterial worth further investigation

Introduction: In reconstructive urology, autologous tissues such as intestinal segments, skin, and oral mucosa are used. Due to their limitations, reconstructive urologists are waiting for a novel material, which would be suitable for urinary tract wall replacement. Human amniotic membrane (AM) is a naturally derived biomaterial with a capacity to support reepithelization and inhibit scar formation. AM has a potential to become a considerable asset for reconstructive urology, i.e., reconstruction of ureters, urinary bladder, and urethrae. Areas covered: This review aims to discuss the potential application of human AM in reconstructive urology. The environment for urinary tract healing is particularly unfavorable due to the presence of urine. Due to its fetal origin, the bioactivity of AM is orientated to induce intrinsic regeneration mechanisms and inhibit scarring. This review introduces the concept of applying human AM in reconstructive urology procedures to improve their outcomes and future tissue engineering based strategies. Expert opinion: Many fields of medicine that have accomplished translational research have proven the usefulness of AM in clinical practice. There is an urgent need for studies to be conducted on large animal models that might convincingly demonstrate the underestimated potential of AM to urologists around the world.