The effects of cryopreservation on angiogenesis modulation activity of human amniotic membrane

Decellularized Extracellular Matrix Scaffolds for Soft Tissue Augmentation: From Host-Scaffold Interactions to Bottlenecks in Clinical Translation

Along with a paradigm shift in looking at soft tissue fillers from space-filling to bioactive materials, decellularized extracellular matrix (DEM) fillers have gained more attention considering their superior bioactivity. However, the complex mechanisms that govern the interaction between host tissues and DEMs have been partially understood. This review first covers the mechanisms that determine immunogenicity, angiogenesis and vasculogenesis, and recellularization and remodeling after DEM implantation into host tissue, with a particular focus on related findings from filler materials. Accordingly, the review delves into the dual role of macrophages and their M1/M2 polarization paradigm to form both constructive and destructive immune responses to DEM implants. Moreover, the contribution of macrophages in angiogenesis has been elucidated, which includes but is not limited to the secretion of angiogenic growth factors and extracellular matrix (ECM) remodeling. The findings challenge the traditional view of immune cells as solely destructive entities in biomaterials and indicate their multifaceted roles in tissue regeneration. Furthermore, the review discusses how the compositional factors of DEMs, such as the presence of growth factors and matrikines, can influence angiogenesis, cell fate, and differentiation during the recellularization process. It is also shown that the biomechanical properties of DEMs, including tissue stiffness, modulate cell responses through mechanotransduction pathways, and the structural properties of DEMs, such as scaffold porosity, impact cell-cell and cell-ECM interactions. Finally, we pointed out the current clinical applications, the bottlenecks in the clinical translation of DEM biomaterials into soft tissue fillers, as well as the naïve research areas of the field.

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.

Angiogenesis and Re-endothelialization in decellularized scaffolds: Recent advances and current challenges in tissue engineering

Decellularization of tissues and organs has recently become a promising approach in tissue engineering and regenerative medicine to circumvent the challenges of organ donation and complications of transplantations. However, one main obstacle to reaching this goal is acellular vasculature angiogenesis and endothelialization. Achieving an intact and functional vascular structure as a vital pathway for supplying oxygen and nutrients remains the decisive challenge in the decellularization/re-endothelialization procedure. In order to better understand and overcome this issue, complete and appropriate knowledge of endothelialization and its determining variables is required. Decellularization methods and their effectiveness, biological and mechanical characteristics of acellular scaffolds, artificial and biological bioreactors, and their possible applications, extracellular matrix surface modification, and different types of utilized cells are factors affecting endothelialization consequences. This review focuses on the characteristics of endothelialization and how to optimize them, as well as discussing recent developments in the process of re-endothelialization.

Mini-Conjunctival Limbal Autograft (Mini-CLAU) Using Platelet-Rich Plasma Eye Drops (E-PRP): A Case Series

PURPOSE

The purpose of this study was to introduce a new method of limbal stem cell transplantation using autologous platelet-rich plasma (E-PRP) eye drops for unilateral total limbal stem cell deficiency.

METHODS

Patients with total unilateral limbal stem cell deficiency due to chemical burn underwent mini-conjunctival limbal autograft using autologous E-PRP drops. One small limbal block, measuring 2 × 2 mm, was harvested from the patients' contralateral healthy eye and transplanted to the diseased eye. All patients received E-PRP drops until achieving complete corneal epithelialization. Subsequent corneal transplantation was performed in eyes with significant stromal opacification. Corneal buttons obtained during corneal transplantation underwent immunohistochemistry for the evaluation of limbal stem cell markers (ABCG2 and P63). Visual acuity, epithelial healing, corneal clarity, and regression of corneal conjunctivalization/vascularization were evaluated after surgery.

RESULTS

Ten patients with acid (n = 7) or alkali (n = 3) burn were included. The mean follow-up period was 21.7 ± 5.8 months (range, 12-32 months). Corneas were completely reepithelialized within 14.9 ± 3.5 days (range, 11-21 days). Corneal conjunctivalization/vascularization dramatically regressed 1 to 2 months after surgery in all cases, and corneal clarity considerably improved in 7 patients. In the 3 eyes with significant stromal opacification, subsequent optical penetrating keratoplasty was performed. The ocular surface was stable throughout the follow-up period in all eyes. BSCVA improved to 0.60 ± 0.0.32 and 0.46 ± 0.0.25 logMAR in eyes with and without corneal transplantation, respectively, at the final follow-up visit. ABCG2 and P63 markers were detected on corneal buttons after keratoplasty.

CONCLUSIONS

Based on our clinical and laboratory findings, mini-conjunctival limbal autograft using E-PRP can be considered as a promising alternative to ocular surface reconstruction.

Recent Advances on Cell-Based Co-Culture Strategies for Prevascularization in Tissue Engineering

Currently, the fabrication of a functional vascular network to maintain the viability of engineered tissues is a major bottleneck in the way of developing a more advanced engineered construct. Inspired by vasculogenesis during the embryonic period, the in vitro prevascularization strategies have focused on optimizing communications and interactions of cells, biomaterial and culture conditions to develop a capillary-like network to tackle the aforementioned issue. Many of these studies employ a combination of endothelial lineage cells and supporting cells such as mesenchymal stem cells, fibroblasts, and perivascular cells to create a lumenized endothelial network. These supporting cells are necessary for the stabilization of the newly developed endothelial network. Moreover, to optimize endothelial network development without impairing biomechanical properties of scaffolds or differentiation of target tissue cells, several other factors, including target tissue, endothelial cell origins, the choice of supporting cell, culture condition, incorporated pro-angiogenic factors, and choice of biomaterial must be taken into account. The prevascularization method can also influence the endothelial lineage cell/supporting cell co-culture system to vascularize the bioengineered constructs. This review aims to investigate the recent advances on standard cells used in in vitro prevascularization methods, their co-culture systems, and conditions in which they form an organized and functional vascular network.

Stem cell-based therapy for ameliorating intrauterine adhesion and endometrium injury

Intrauterine adhesion refers to endometrial repair disorders which are usually caused by uterine injury and may lead to a series of complications such as abnormal menstrual bleeding, recurrent abortion and secondary infertility. At present, therapeutic approaches to intrauterine adhesion are limited due to the lack of effective methods to promote regeneration following severe endometrial injury. Therefore, to develop new methods to prevent endometrial injury and intrauterine adhesion has become an urgent need. For severely damaged endometrium, the loss of stem cells in the endometrium may affect its regeneration. This article aimed to discuss the characteristics of various stem cells and their applications for uterine tissue regeneration.

Use of Amniotic Membrane and Its Derived Products for Bone Regeneration: A Systematic Review

Thanks to their biological properties, amniotic membrane (AM), and its derivatives are considered as an attractive reservoir of stem cells and biological scaffolds for bone regenerative medicine. The objective of this systematic review was to assess the benefit of using AM and amniotic membrane-derived products for bone regeneration. An electronic search of the MEDLINE-Pubmed database and the Scopus database was carried out and the selection of articles was performed following PRISMA guidelines. This systematic review included 42 articles taking into consideration the studies in which AM, amniotic-derived epithelial cells (AECs), and amniotic mesenchymal stromal cells (AMSCs) show promising results for bone regeneration in animal models. Moreover, this review also presents some commercialized products derived from AM and discusses their application modalities. Finally, AM therapeutic benefit is highlighted in the reported clinical studies. This study is the first one to systematically review the therapeutic benefits of AM and amniotic membrane-derived products for bone defect healing. The AM is a promising alternative to the commercially available membranes used for guided bone regeneration. Additionally, AECs and AMSCs associated with an appropriate scaffold may also be ideal candidates for tissue engineering strategies applied to bone healing. Here, we summarized these findings and highlighted the relevance of these different products for bone regeneration.

Human Amniotic Membrane: A review on tissue engineering, application, and storage

Human amniotic membrane (hAM) has been employed as scaffolding material in a wide range of tissue engineering applications, especially as a skin dressing and as a graft for corneal treatment, due to the structure of the extracellular matrix and excellent biological properties that enhance both wound healing and tissue regeneration. This review highlights recent work and current knowledge on the application of native hAM, and/or production of hAM-based tissue-engineered products to create scaffolds mimicking the structure of the native membrane to enhance the hAM performance. Moreover, an overview is presented on the available (cryo) preservation techniques for storage of native hAM and tissue-engineered products that are necessary to maintain biological functions such as angiogenesis, anti-inflammation, antifibrotic and antibacterial activity.

The Bottlenecks in Translating Placenta-Derived Amniotic Epithelial and Mesenchymal Stromal Cells Into the Clinic: Current Discrepancies in Marker Reports

Placenta-derived amniotic cells have prominent features for application in regenerative medicine. However, there are still discrepancies in the characterization of human amniotic epithelial and mesenchymal stromal cells. It seems crucial that the characterization of human amniotic membrane cells be investigated to determine whether there are currently discrepancies in their characterization reports. In addition, possible causes for the witnessed discrepancies need to be addressed toward paving the way for further clinical application and safer practices. The objective of this review is to investigate the marker characterization as well as the potential causes of the discrepancies in the previous reports on placenta-derived amniotic epithelial and mesenchymal stromal cells. The current discrepancies could be potentially due to reasons including passage number and epithelial to mesenchymal transition (EMT), cell heterogeneity, isolation protocols and cross-contamination, the region of cell isolation on placental disk, measuring methods, and gestational age.

Stem Cell Therapy for Hepatocellular Carcinoma: Future Perspectives

Hepatocellular carcinoma (HCC) is one of the most common types of cancer and results in a high mortality rate worldwide. Unfortunately, most cases of HCC are diagnosed in an advanced stage, resulting in a poor prognosis and ineffective treatment. HCC is often resistant to both radiotherapy and chemotherapy, resulting in a high recurrence rate. Although the use of stem cells is evolving into a potentially effective approach for the treatment of cancer, few studies on stem cell therapy in HCC have been published. The administration of stem cells from bone marrow, adipose tissue, the amnion, and the umbilical cord to experimental animal models of HCC has not yielded consistent responses. However, it is possible to induce the apoptosis of cancer cells, repress angiogenesis, and cause tumor regression by administration of genetically modified stem cells. New alternative approaches to cancer therapy, such as the use of stem cell derivatives, exosomes or stem cell extracts, have been proposed. In this review, we highlight these experimental approaches for the use of stem cells as a vehicle for local drug delivery.

How preparation and preservation procedures affect the properties of amniotic membrane? How safe are the procedures?

Human amniotic membrane (AM) has been widely used for tissue engineering and regenerative medicine applications. AM has many favorable characteristics such as high biocompatibility, antibacterial activity, anti-scarring property, immunomodulatory effects, anti-cancer behavior and contains several growth factors that make it an excellent natural candidate for wound healing. To date, various methods have been developed to prepare, preserve, cross-link and sterilize the AM. These methods remarkably affect the morphological, physico-chemical and biological properties of AM. Optimization of an effective and safe method for preparation and preservation of AM for a specific application is critical. In this review, the isolation, different methods of preparation, preservation, cross-linking and sterilization as well as their effects on properties of AM are well discussed. For each section, at least one effective and safe protocol is described in detail.

Potential Therapeutic Features of Human Amniotic Mesenchymal Stem Cells in Multiple Sclerosis: Immunomodulation, Inflammation Suppression, Angiogenesis Promotion, Oxidative Stress Inhibition, Neurogenesis Induction, MMPs Regulation, and Remyelination Stimulation

Multiple sclerosis (MS) is an inflammatory and degenerative disorder of the central nervous system with unknown etiology. It is accompanied by demyelination of the nerves during immunological processes in the presence of oxidative stress, hypoxia, cerebral hypo-perfusion, and dysregulation in matrix metalloproteinases (MMPs). Human amniotic mesenchymal stem cells (hAMSCs) as pluripotent stem cells possess some conspicuous features which could be of therapeutic value in MS therapy. hAMSCs could mimic the cascade of signals and secrete factors needed for promoting formation of stable neovasculature and angiogenesis. hAMSCs also have immunomodulatory and immunosuppressive effects on inflammatory processes and reduce the activity of inflammatory cells, migration of microglia and inhibit recruitment of certain immune cells to injury sites. hAMSCs attenuate the oxidative stress supported by the increased level of antioxidant enzymes and the decreased level of lipid peroxidation products. Furthermore, hAMSCs enhance neuroprotection and neurogenesis in brain injuries by inhibition of inflammation and promotion of neurogenesis. hAMSCs could significantly increase the expression of neurotrophic factors, which prevents neurons from initiating programmed cell death and improves survival, development, and function of neurons. In addition, they induce differentiation of neural progenitor cells to neurons. hAMSCs could also inhibit MMPs dysregulation and consequently promote the survival of endothelial cells, angiogenesis and the stabilization of vascular networks. Considering the mentioned evidences, we hypothesized here that hAMSCs and their conditioned medium could be of therapeutic value in MS therapy due to their unique properties, including immunomodulation and inflammation suppression; angiogenesis promotion; oxidative stress inhibition; neurogenesis induction and neuroprotection; matrix metalloproteinases regulation; and remyelination stimulation.

Amniotic membrane and its epithelial and mesenchymal stem cells as an appropriate source for skin tissue engineering and regenerative medicine

One of the main goals of tissue engineering and regenerative medicine is to develop skin substitutes for treating deep dermal and full thickness wounds. In this regard, both scaffold and cell source have a fundamental role to achieve exactly the same histological and physiological analog of skin. Amnion epithelial and mesenchymal cells possess the characteristics of pluripotent stem cells which have the capability to differentiate into all three germ layers and can be obtained without any ethical concern. Amniotic cells also produce different growth factors, angio-modulatory cytokines, anti-bacterial peptides and a wide range of anti-inflammatory agents which eventually cause acceleration in wound healing. In addition, amniotic membrane matrix exhibits characteristics of an ideal scaffold and skin substitute through various types of extracellular proteins such as collagens, laminins and fibronectins which serve as an anchor for cell attachment and proliferation, a bed for cell delivery and a reservoir of drugs and growth factors involved in wound healing process. Recently, isolation of amniotic cells exosomes, surface modification and cross-linking approaches, construction of amnion based nanocomposites and impregnation of amnion with nanoparticles, construction of amnion hydrogel and micronizing process promoted its properties for tissue engineering. In this manuscript, the recent progress was reviewed which approve that amnion-derived cells and matrix have potential to be involved in skin substitutes; an enriched cell containing scaffold which has a great capability to be translated into the clinic.

Ulinastatin Supplementation During Human Amniotic Membrane Preservation to Improve its Viability

PURPOSE

The amniotic membrane (AM) is the transparent innermost layer of the placenta and it facilitates rapid wound healing in a diversity of ocular surface disorders. However, extended periods of cryopreservation before use induce significant impairment of cell viability due to oxidative stresses and inflammatory responses. We investigated the effect of supplementing ulinastatin (ULI), a known serine protease inhibitor, and relevant mechanisms of action in AM preservation solution through the hypothermic continuum on inflammatory and apoptotic signals and viability of AM tissue.

MATERIALS AND METHODS

The expression of inflammatory signal factors, including high mobility group box 1 (HMGB1), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), receptor-interacting serine/threonine-protein kinase 3 (RIPK3) and anti-TNF-inducible gene 6 (TSG-6) which is a TNF-α-inducible anti-inflammatory protein, and the expression of apoptotic signal factors, including caspase (Cas)-9 and Cas-8, the initiators, and Cas-3, the executioner caspase and Bax were analyzed with or without ULI during hypothermic preservation of human AM. Subsequently, the actual viability of human AM tissue was verified with or without ULI supplementation throughout hypothermic continuum (both hypothermic- and cryopreservation).

RESULTS

Hypothermic AM preservation with ULI for 48 h resulted in downregulated expression of cold-inducible inflammatory factors, including HMGB1 and NF-κB, as well as RIPK3. In addition, ULI suppressed apoptotic signals related with Cas-9, Cas-8, and Cas-3 under hypothermic conditions. Furthermore, ULI supplementation during hypothermic- and cryopreservation of AM significantly enhanced viability of AM tissue and amniotic epithelial cells.

CONCLUSIONS

Supplementation of ULI during human AM preservation through the hypothermic continuum may be a feasible dual anti-inflammatory and anti-apoptotic strategy that enhances the viability of AM tissue.

Induction of antimicrobial peptides secretion by IL-1β enhances human amniotic membrane for regenerative medicine

Due to antibacterial characteristic, amnion has been frequently used in different clinical situations. Developing an in vitro method to augment endogenous antibacterial ingredient of amniotic epithelial and mesenchymal stem cells is desirable for a higher efficacy of this promising biomaterial. In this study, epithelial or mesenchymal side dependent effect of amniotic membrane (AM) on antibacterial activity against some laboratory and clinical isolated strains was investigated by modified disk diffusion method and colony count assay. The effect of exposure to IL-1β in production and release of antibacterial ingredients was investigated by ELISA assay. The results showed that there is no significant difference between epithelial and mesenchymal sides of amnion in inhibition of bacterial growth. Although the results of disk diffusion showed that the AM inhibitory effect depends on bacterial genus and strain, colony count assay showed that the extract of AM inhibits all investigated bacterial strains. The exposure of AM to IL-1β leads to a higher level of antibacterial peptides secretion including elafin, HBD-2, HBD-3 and cathelicidic LL-37. Based on these results, amniotic cells possess antibacterial activity which can be augmented by inflammatory signal inducers; a process which make amnion and its epithelial and mesenchymal stem cells more suitable for tissue engineering and regenerative medicine.

Safety and Efficacy of Amnion Graft in Preventing Reformation of Intrauterine Adhesions

STUDY OBJECTIVE

To determine the safety and efficacy of amnion grafts in preventing the recurrence of intrauterine adhesions after hysteroscopic adhesiolysis in women with severe intrauterine adhesions.

DESIGN

A retrospective matched cohort study including 120 patients treated during 62 months (Canadian Task Force classification II-2).

SETTING

A tertiary referral center.

PATIENTS

A total of 120 patients who underwent intrauterine adhesiolysis for severe intrauterine adhesions: 40 patients in the treatment group and 80 patients in the control group matched for age and adhesion scores. The mean duration of follow-up was 14.6 months.

INTERVENTION

A Foley balloon with/without a fresh amnion graft was introduced into the uterine cavity after hysteroscopic adhesiolysis.

MEASUREMENTS AND MAIN RESULTS

In both groups, the balloon was kept in place for 7 days, cyclic hormone treatment was given for 3 months, and second-look and third-look hysteroscopies were performed 1 and 3 months after the operation. Outcome measures included the incidence of the recurrence of intrauterine adhesions, the score of intrauterine adhesions (if present), and the impact of the surgery on the amount of menstrual flow. In the study group, the menstrual score at the end of 3 months was significantly higher, and the intrauterine adhesion score at third-look hysteroscopy was significantly lower compared with those in the control group. The incidences of the recurrence of intrauterine adhesions at third-look hysteroscopy in the treatment and control groups were 30% and 48.7%, respectively (p = .05). The adhesion scores at third-look hysteroscopy in the treatment and control groups were 1.3 and 2.1, respectively (p < .05).

CONCLUSION

The use of an amnion graft after intrauterine adhesiolysis appears to be beneficial in improving menstruation and reducing the recurrence of adhesion reformation.

Ultrastructural characteristics and immune profile of equine MSCs from fetal adnexa

Both in human and equine species, mesenchymal stem cells (MSCs) from amniotic membrane (AM) and Wharton's jelly (WJ), may be particularly useful for immediate use or in later stages of life, after cryopreservation in cell bank. The aim of this study was to compare equine AM- and WJ-MSCs in vitro features that may be relevant for their clinical employment. MSCs were more easily isolated from WJ, even if MSCs derived from AM exhibited more rapid proliferation (P < 0.05). Osteogenic and chondrogenic differentiation were more prominent in MSCs derived from WJ. This is also suggested by the lower adhesion of AM cells, demonstrated by the greater volume of spheroids after hanging drop culture (P < 0.05). Data obtained by PCR confirmed the immunosuppressive function of AM and WJ-MSCs and the presence of active genes specific for anti-inflammatory and angiogenic factors (IL-6, IL 8, IL-β1). For the first time, by means of transmission electron microscopy (TEM), we ascertained that equine WJ-MSCs constitutively contain a very impressive number of large vesicular structures, scattered throughout the cytoplasm. Moreover, an abundant extracellular fibrillar matrix was located in the intercellular spaces among WJ-MSCs. Data recorded in this study reveal that MSCs from different fetal tissues have different characteristics that may drive their therapeutic use. These finding could be noteworthy for horses as well as for other mammalian species, including humans.

Different Light Transmittance of Placental and Reflected Regions of Human Amniotic Membrane That Could Be Crucial for Corneal Tissue Engineering

PURPOSE

Because of long-term incorporation of amniotic membrane (AM) into corneal stroma after transplantation as a scaffold for stem cell delivery, the variation in haziness is a major factor that influences visual quality. The aim of this study was to evaluate probable sources of transparency variation in fresh and freeze-dried AM and compare the obtained results with transparency of rabbit corneas.

METHODS

Amnions were extracted from placental and reflected regions of placentas from elective Cesarean sections. The effects of removing epithelial cells and spongy layer on transparency and thickness of fresh and freeze-dried AMs and rabbit cornea were evaluated. The epithelial surface of AMs was evaluated with histological analysis and scanning electron microscopy.

RESULTS

The reflected region of intact AM was thinner and more transparent than the placental region. From histological analysis, the main source of difference between placental and reflected regions of amnion is related to epithelial cells. The process of acellularization improved light transmission of the AM in both placental and reflected regions and also omitted variation between transparency of reflected and placental regions of AM. Freeze-drying of intact AM did not improve transparency because of scattering of light by cellular debris; however, removing the epithelial layer before freeze-drying resulted in optimized light transmission similar to transparency of rabbit cornea.

CONCLUSIONS

The amniotic epithelial cells play a major role as a source of variation in light transmission properties of amnion. From the results, epithelial-denuded freeze-dried AM was found to be a suitable scaffold to be applied in corneal tissue engineering.

The effect of cryopreservation on anti-cancer activity of human amniotic membrane

Human amniotic membrane (AM) is an appropriate candidate for treatment of cancer due to special properties, such as inhibition of angiogenesis and secretion of pro-apoptotic factors. This research was designed to evaluate the impact of cryopreservation on cancer cell death induction and anti-angiogenic properties of the AM. Cancer cells were treated with fresh and cryopreserved amniotic condition medium during 24 h and cancer cell viability was determined by MTT assay. To evaluate angiogenesis, the rat aorta ring assay was performed for both fresh and cryopreserved AM within 7 days. In addition, four anti-angiogenic factors Tissue Inhibitor of Matrix Metalloproteinase-1 and 2 (TIMP-1 and TIMP-2), Thrombospondin, and Endostatin were measured by ELISA assay before and after cryopreservation. The results showed that the viability of cultured cancer cells dose-dependently decreased after treatment with condition medium of fresh and cryopreserved tissue and no significant difference was observed between the fresh and cryopreserved AM. The results revealed that the amniotic epithelial stem cells inhibit the penetration of fibroblast-like cells and angiogenesis. Moreover, the penetration of fibroblast-like cells in both epithelial and mesenchymal sides of fresh and cryopreserved AM was observed after removing of epithelial cells. The cryopreservation procedure significantly decreased anti-angiogenic factors TIMP-1, TIMP-2, Thrombospondin, and Endostatin which shows that angio-modulatory property is not fully dependent on proteomic and metabolomic profiles of the AM. These promising results demonstrate that cancer cell death induction and anti-angiogenic properties of the AM were maintained within cryopreservation; a procedure which can circumvent limitations of the fresh AM.

Clinical application of decellularized and lyophilized human amnion/chorion membrane grafts for closing post-laryngectomy pharyngocutaneous fistulas

Background and Objectives

Squamous cell carcinoma is the most common pathological type among the cancers of the larynx. Standard treatment for squamous cell carcinoma of the larynx is the combination of chemotherapy, radiotherapy, and laryngectomy. Pharyngocutaneous fistula is a common complication of laryngectomy. We hypothesized that decellularized and lyophilized human amnion/chorion membrane can be an effective, non‐invasive method of treating pharyngocutaneous fistula.

Methods

A total of 67 patients with laryngeal squamous cell carcinoma were retrospectively analyzed after treatment in a prospective trial. After preoperative chemotherapy, radiotherapy, and total or extended laryngectomy, primary wound healing occurred in 42 (62.7%) patients. Pharyngocutaneous fistula developed in 8 (11.9%) patients. Decellularized and lyophilized human amnion/chorion membrane grafts were used to reconstruct the fistulas.

Results

The average time for the full healing of the wound in all patients after transplantation of these grafts was 18 days.

Conclusion

The advantages of using these grafts over other existing methods of pharyngocutaneous fistula treatment are that they are non‐invasive, prevent donor morbidity, and enable management of the wound without using classical wound gauze. J. Surg. Oncol. 2016;113:538–543. © 2016 The Authors. Journal of Surgical Oncology Published by Wiley Periodicals, Inc.