Characterisation of dehydrated amnion chorion membranes and evaluation of fibroblast and keratinocyte responses in vitro

Dehydrated Amnion Chorion Membrane versus standard of care for diabetic foot ulcers: a randomised controlled trial

OBJECTIVE

Diabetic foot ulcers (DFUs) continue to challenge wound care practitioners. This prospective, multicentre, randomised controlled trial (RCT) evaluated the effectiveness of a dehydrated Amnion Chorion Membrane (dACM) (Organogenesis Inc., US) versus standard of care (SoC) alone in complex DFUs in a challenging patient population.

METHOD

Subjects with a DFU extending into dermis, subcutaneous tissue, tendon, capsule, bone or joint were enrolled in a 12-week trial. They were allocated equally to two treatment groups: dACM (plus SoC); or SoC alone. The primary endpoint was frequency of wound closure determined by a Cox analysis that adjusted for duration and wound area. Kaplan-Meier analysis was used to determine median time to complete wound closure (CWC).

RESULTS

The cohort comprised 218 patients, and these were split equally between the two treatment groups with 109 patients in each. A Cox analysis showed that the estimated frequency of wound closure for the dACM plus SoC group was statistically superior to the SoC alone group at week 4 (12% versus 8%), week 6 (22% versus 11%), week 8 (31% versus 21%), week 10 (42% versus 27%) and week 12 (50% versus 35%), respectively (p=0.04). The computed hazard ratio (1.48 (confidence interval: 0.95, 2.29) showed a 48% greater probability of wound closure in favour of the dACM group. Median time to wound closure for dACM-treated ulcers was 84 days compared to 'not achieved' in the SoC-treated group (i.e., ≥50% of SoC-treated DFUs failed to heal by week 12; p=0.04).

CONCLUSION

In an adequately powered DFU RCT, dACM increased the frequency, decreased the median time, and improved the probability of CWC when compared with SoC alone. dACM demonstrated beneficial effects in DFUs in a complex patient population.

DECLARATION OF INTEREST

This study was funded by Organogenesis Inc., US. JC serves as a consultant and speaker for Organogenesis. RDD serves as a speaker for Organogenesis. OMA and MLS serve as consultants for Organogenesis. The authors have no other conflicts of interest to declare.

Assessment of the proteome profile of decellularized human amniotic membrane and its biocompatibility with umbilical cord-derived mesenchymal stem cells

Extracellular matrix-based bio-scaffolds are useful for tissue engineering as they retain the unique structural, mechanical, and physiological microenvironment of the tissue thus facilitating cellular attachment and matrix activities. However, considering its potential, a comprehensive understanding of the protein profile remains elusive. Herein, we evaluate the impact of decellularization on the human amniotic membrane (hAM) based on its proteome profile, physicochemical features, as well as the attachment, viability, and proliferation of umbilical cord-derived mesenchymal stem cells (hUC-MSC). Proteome profiles of decellularized hAM (D-hAM) were compared with hAM, and gene ontology (GO) enrichment analysis was performed. Proteomic data revealed that D-hAM retained a total of 249 proteins, predominantly comprised of extracellular matrix proteins including collagens (collagen I, collagen IV, collagen VI, collagen VII, and collagen XII), proteoglycans (biglycan, decorin, lumican, mimecan, and versican), glycoproteins (dermatopontin, fibrinogen, fibrillin, laminin, and vitronectin), and growth factors including transforming growth factor beta (TGF-β) and fibroblast growth factor (FGF) while eliminated most of the intracellular proteins. Scanning electron microscopy was used to analyze the epithelial and basal surfaces of D-hAM. The D-hAM displayed variability in fibril morphology and porosity as compared with hAM, showing loosely packed collagen fibers and prominent large pore areas on the basal side of D-hAM. Both sides of D-hAM supported the growth and proliferation of hUC-MSC. Comparative investigations, however, demonstrated that the basal side of D-hAM displayed higher hUC-MSC proliferation than the epithelial side. These findings highlight the importance of understanding the micro-environmental differences between the two sides of D-hAM while optimizing cell-based therapeutic applications.

Management of post-Mohs surgical wounds with a hypothermically stored amniotic membrane: a case series

OBJECTIVE

The aim of this case series is to present an alternative approach to managing post-Mohs Micrographic Surgery (Mohs) wounds with hypothermically stored amniotic membrane (HSAM).

METHOD

A case series of patients with post-Mohs wounds is presented, with four patients referred for hard-to-heal wounds following a Mohs procedure that was performed 1-3 months previously. All wounds underwent weekly assessment, debridement, and application of HSAM and secondary dressings. Treatment also included management of bioburden, proper skin care and compression therapy for lower extremity wounds.

RESULTS

This case series of seven wounds consisted of four females and three males with a mean age of 87.6 years. Mean wound size at first application of HSAM was 1.34±1.20cm2. All wounds closed, with an average time to wound closure of 43.7±27.1 days. Patients received an average of 4.6±2.5 HSAM applications. The four post-Mohs wounds with a history of being hard-to-heal had an average time to wound closure of 35.5±16.3 days, with an average duration of 86.5±32.4 days prior to the first HSAM application.

CONCLUSION

The results of this case series suggest that use of HSAM may provide an alternative approach to managing post-Mohs wounds. In addition, these findings suggest that HSAM may be of greatest benefit when applied early after Mohs surgery.

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.

Updates on Recent Clinical Assessment of Commercial Chronic Wound Care Products

Impaired wound healing after trauma, disorders, and surgeries impact millions of people globally every year. Dysregulation in orchestrated healing mechanisms and underlying medical complications make chronic wound management extremely challenging. Besides standard-of-care treatments including broad spectrum antibiotics and wound-debridement, novel adjuvant therapies are clinically tested and commercialized. These include topical agents, skin substitutes, growth factor delivery, and stem cell therapies. With a goal to overcome factors playing pivotal role in delayed wound healing, researchers are exploring novel approaches to elicit desirable healing outcomes in chronic wounds. Although recent innovations in wound care products, therapies, and devices are extensively reviewed in past, a comprehensive review summarizing their clinical outcomes is surprisingly lacking. Herein, this work reviews the commercially available wound care products and their performance in clinical trials to provide a statistically comprehensive understanding of their safety and efficacy. The performance and suitability of various commercial wound care platforms, including xenogeneic and allogenic products, wound care devices, and novel biomaterials, are discussed for chronic wounds. The current clinical evaluation will provide a comprehensive understanding of the benefits and drawbacks of the most-recent approaches and will enable researchers and healthcare providers to develop next-generation technologies for chronic wound management.

Epiretinal Amniotic Membrane in Complicated Retinal Detachment: a Clinical and In Vitro Safety Assessment

INTRODUCTION

Amniotic membrane (AM) is a popular treatment for external ocular diseases. First intraocular implantations in other diseases reported promising results. Here, we review three cases of intravitreal epiretinal human AM (iehAM) transplantation as an adjunct treatment for complicated retinal detachment and analyze clinical safety. Possible cellular rejection reactions against the explanted iehAM were evaluated and its influence was assessed on three retinal cell lines in vitro.

METHODS

Three patients with complicated retinal detachment and implanted iehAM during pars plana vitrectomy are retrospectively presented. After removal of the iehAM at subsequent surgery, tissue-specific cellular responses were studied by light microscopy and immunohistochemical staining. We investigated the influence of AM in vitro on retinal pigment epithelial cells (ARPE-19), Müller cells (Mio-M1), and differentiated retinal neuroblasts (661W) . An anti-histone DNA ELISA for cell apoptosis, a BrdU ELISA for cell proliferation, a WST-1 assay for cell viability, and a live/dead assay for cell death were performed.

RESULTS

Despite the severity of the retinal detachment, stable clinical outcomes were obtained in all three cases. Immunostaining of the explanted iehAM showed no evidence of cellular immunological rejection. In vitro, there was no statistical significant change in cell death or cell viability nor were proliferative effects detected on ARPE-19, Müller cells, and retinal neuroblasts exposed to AM.

CONCLUSION

iehAM was a viable adjuvant with many potential benefits for treatment of complicated retinal detachment. Our investigations could not detect any signs of rejection reactions or toxicity. Further studies are needed to evaluate this potential in more detail.

Healing of a chronic ulcer of the lower limb of venous origin with fresh human amniochorionic membrane allograft

In its fresh state, the amniochorionic membrane contains various multipotential cells, growth factors, and extracellular matrix proteins that contribute to the healing of chronic vascular ulcers. To demonstrate its effectiveness, a fresh human placental membrane allograft was applied to a chronic venous ulcer in the lower limb of an 89-year-old female patient with a 12 x 10 cm ulcerated lesion of 40 years of evolution in the malleolar area of her left lower limb. Sixty days after the graft, the ulcer was healed in 100% of its surface and a light pink scar on the edges indicated possible pigmentation. Fresh human amniochorionic membrane allograft is a therapeutic alternative for the healing of refractory chronic vascular ulcers of the lower extremities.

Biophysical Characterization of a Novel Tri-Layer Placental Allograft Membrane

Objective: Placental tissues, including membranes composed of amnion and chorion, are promising options for the treatment of chronic wounds. Amnion and chorion contain multiple extracellular matrix (ECM) proteins and a multitude of growth factors and cytokines that, when used clinically, assist in the progression of difficult to heal wounds through restoration of a normal healing process. The objective of this study was to characterize the in vitro physical and biological properties of a dehydrated tri-layer placental allograft membrane (TPAM) consisting of a chorion layer sandwiched between two layers of amnion. Approach: Mechanical properties were evaluated by mechanical strength and enzyme degradation assays. The ECM composition of TPAM membranes was evaluated by histological staining while growth factors and cytokine presence was evaluated by a multiplex enzyme-linked immunosorbent assay. Proliferation, migration, and ECM secretion assays were performed with fibroblasts. Immunomodulatory properties were assessed by a pro-inflammatory cytokine reduction assay while the macrophage phenotype was determined by quantifying the ratio of M1 versus M2 secreted factors. Results: The unique three-layer construction improves mechanical handling properties over single- and bi-layer membranes. Results demonstrate that TPAM is rich in ECM proteins, growth factors, cytokines, and tissue inhibitors of metalloproteinases, and favorably influences fibroblast migration, proliferation, and ECM secretion when compared to negative controls. Furthermore, after processing and preservation, these membranes maintain their intrinsic immunomodulatory properties with the ability to suppress pro-inflammatory processes and modulate the M1 and M2 macrophage phenotype toward a pro-regenerative profile when compared to a negative control. Innovation: This is the first study to characterize both the biophysical and biological properties of a tri-layer placental membrane. Conclusion: This work demonstrates that TPAM has improved handling characteristics over single- and bi-layer membranes, stimulates pro-healing cellular responses, and advantageously modulates inflammatory responses, altogether making this scaffold a promising option for treating wounds, especially those that are complex or difficult to heal.

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

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

Biomaterial-based treatments for the prevention of preterm birth after iatrogenic rupture of the fetal membranes

Minimally invasive interventions to ameliorate or correct fetal abnormalities are becoming a clinical reality. However, the iatrogenic premature preterm rupture of the fetal membranes (FMs) (iPPROM), which may result in...

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

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

Comprehensive quantitative characterization of the human term amnion proteome

•

We report an unprecedented quantitative high coverage of the human amnion proteome.

•

We identified novel proteins that hold great promise for understanding fetal membrane biology.

•

Together, this comprehensive proteome provides a basis for the evaluation of pre-term or diseased fetal membranes.

The loss of fetal membrane (FM) integrity and function at an early time point during pregnancy can have devastating consequences for the fetus and the newborn. However, biomaterials for preventive sealing and healing of FMs are currently non-existing, which can be partly attributed to the current fragmentary knowledge of FM biology. Despite recent advances in proteomics analysis, a robust and comprehensive description of the amnion proteome is currently lacking. Here, by an optimized protein sample preparation and offline fractionation before liquid chromatography coupled to mass spectrometry (LC-MS) analysis, we present a characterization of the healthy human term amnion proteome, which covers more than 40% of the previously reported transcripts in similar RNA sequencing datasets and, with more than 5000 identifications, greatly outnumbers previous reports. Together, beyond providing a basis for the study of compromised and preterm ruptured FMs, this comprehensive human amnion proteome is a stepping-stone for the development of novel healing-inducing biomaterials. The proteomic dataset has been deposited in the ProteomeXchange Consortium with the identifier PXD019410.

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.

A prospective clinical trial evaluating changes in the wound microenvironment in patients with chronic venous leg ulcers treated with a hypothermically stored amniotic membrane

Amniotic tissues have been long utilised to treat chronic wounds; however, there are few studies evaluating how the wound microenvironment responds to these therapies. The goal of this study was to evaluate the changes in wounds treated with a hypothermically stored amniotic membrane (HSAM). In this prospective single‐arm study, 15 female patients with venous leg ulcers were treated with HSAM from male donors and standard of care for 12 weeks. Over the course of the study, wound exudate was collected and evaluated using proteomic microarrays. Biopsies were collected during the course of treatment to detect the presence of HSAM tissue. By 4 weeks, 60% of subjects achieved 50% or greater reduction in wound size, and by 12 weeks, 53% of subjects achieved 100% re‐epithelialization. HSAM DNA was detected in 20% of biopsies as determined by the detection TSPY4, indicating HSAM was no longer present within the wound bed approximately 7 days from the last treatment for the majority of wounds. Proteomic analysis of wound exudate found that wounds on a healing trajectory had significantly higher levels of MMP‐10, MMP‐7, and TIMP‐4 and significantly lower levels of CX3CL1, FLT‐3 L, IL‐1ra, IL‐1a, IL‐9, IL‐2, IL‐3, MCP‐1, and TNF‐b compared with other wounds.

A dehydrated, aseptically-processed human amnion/chorion allograft accelerates healing in a delayed murine excisional wound model

Since chronic, non-healing wounds represent an increasing source of economic and temporal burden for patients who suffer from them and healthcare professionals that treat them, therapeutic modalities that promote closure of delayed and non-healing wounds are of utmost importance. Recent clinical results of allografts derived from amnion and chorion placental layers encourage further investigation of the mechanisms underlying clinical efficacy of these products for treatment of wounds. Here, we utilized a diabetic murine splinted excisional wound model to investigate the effects of a dehydrated human amnion/chorion-derived allograft (dHACA) on delayed wound healing, as well as the effects of dehydrated allograft derived solely from amnion tissue of the same donor. We examined wound healing by histological endpoint analysis, and we assessed other parameters relevant to functional wound healing in the wound bed including angiogenesis, macrophage phenotypes, proliferative activity, and gene expression. Herein we demonstrate that application of dHACA to a murine diabetic model of delayed wound progression results in better macroscale wound resolution outcomes, including rate of closure, compared to unaided wound progression, while dehydrated human amnion allograft (dHAA) fails to improve outcomes. Improved gross wound resolution observed with dHACA was accompanied by increased granulation tissue formation, proliferation and vascular ingrowth observed in the wound bed, early macrophage polarization towards anti-inflammatory phenotypes, and downregulation of pro-fibrotic gene expression. Overall, our data suggest that improvements in the rates of delayed wound closure observed from combined amnion/chorion allografts are associated with modulation of critical cellular and tissue processes commonly found to be dysregulated in delayed healing wounds, including proliferation, vascularization, inflammation, and re-epithelialization.

Innovative use of increasing the width of attached gingiva using chorion membrane along with platelet rich fibrin membrane

Width of attached gingiva plays an important role in maintaining periodontal health, provides stabilization of the gingival margin against frictional forces and aids in dissipating physiological forces exerted by the muscular fibers of the alveolar mucosa on the gingival tissues. Inadequate width of attached gingiva leads to attachment loss, soft tissue recession, and impedes oral hygiene measures. Hence, procedures using autografts and allografts have been proposed to augment the attached gingiva. Allografts like chorionic membrane (CM) are known to enhance release of growth factors, promote neovascularization, healing and enhance biotype. To assess the efficacy of CM in increasing the width of attached gingiva, vestibular depth and gingival thickness. Fifteen patients with inadequate attached gingival width were included in the study. Patients were randomly allocated to each group: Control group, CM group and CM + platelet rich fibrin (PRF) group. Attached gingiva width, vestibular depth, and gingival thickness were measured at baseline and 4 weeks post procedure. The control, CM and CM + PRF groups showed an increase in all parameters from baseline to 4 weeks. The increase in the attached gingiva (p = 0.042) width, vestibular depth (p = 0.043) and gingival thickness (p = 0.034) were statistically significant at 4 weeks for CM group and CM + PRF group respectively. The CM + PRF group showed better results compared to other groups. CM and PRF can be effectively incorporated to increase the width of attached gingiva and depth of vestibule.

A mechanistic evaluation of the angiogenic properties of a dehydrated amnion chorion membrane in vitro and in vivo

Angiogenesis is essential for the successful repair of tissues; however, in many chronic conditions, angiogenesis is inhibited. Placental tissues have been shown to illicit an angiogenic response both in vitro and in vivo, and the angiogenic properties of these tissues likely contribute to observed clinical outcomes. Although there is some work describing the angiogenic effects of these tissues, comparatively little has been done to determine the possible mechanisms responsible for this effect. The purpose of this study was to conduct a thorough evaluation of a commercially available dehydrated amnion chorion membrane to better understand how these tissues may promote angiogenesis. The proteomic content of this tissue was evaluated using a high throughput proteomic microarray, and then the effects of these grafts were evaluated in vivo using subcutaneous gelfoam sponge implants containing conditioned media (CM) from the graft. Human microvascular endothelial cells were then used to determine how released factors effect migration, proliferation, gene expression, and protein production in vitro. Finally, to elucidate potential signaling‐pathways through which tissue‐derived factors act to induce pro‐angiogenetic phenotypes in endothelial cells in vitro, we performed a global analysis of both serine/threonine and tyrosine kinase activity. Kinomic and proteomic data were then combined to generate protein–protein interaction networks that enabled the identification of multiple growth factors and cytokines with both pro‐ and anti‐angiogenetic properties. In vivo, the addition of CM resulted in increased CD31 and αSMA staining and increases in pro‐angiogenic gene expression. In vitro, CM resulted in significant increases in endothelial proliferation, migration, and the expression of granulocyte‐macrophage colony‐stimulating factor, hepatocyte growth factor, and transforming growth factor beta‐3. Integrated kinomic analysis implicated ERK1/2 signaling as the primary pathway activated following culture of endothelial cells with dehydrated amnion/chorion membrane (dACM) CM. In conclusion, dACM grafts triggered pro‐angiogenic responses both in vitro and in vivo that are likely at least partially mediated by ERK1/2 signaling.

Characterisation of dehydrated amnion chorion membranes and evaluation of fibroblast and keratinocyte responses in vitro

The purpose of this study is to characterise the composition of a dehydrated amnion and chorion graft and investigate how factors released from this graft interact with cells important to the wound microenvironment using in vitro models. Characterisation was completed by proteomic analysis of growth factors and cytokines, evaluation of matrix components and protease inhibition, immunohistochemistry, and in vitro release of key growth factors and cytokines. To evaluate the effect of released factors on cells found within the microenvironment, in vitro assays including: cell proliferation, migration, gene expression, protein production, and intracellular pathway activation were used; additionally, responses of fibroblasts in the context of inflammation were measured. We found that released factors from dehydrated amnion/chorion membranes (dACM) stimulated cell proliferation, migration, and altered gene and protein expression profiles of cells important for wound repair in vitro. When cells were cultured in the presence of pro‐inflammatory cytokines, the addition of releasate from dACM resulted in an altered production of cytokines, including a reduction of pro‐inflammatory regulated on activation, normal T cell expressed and secreted (RANTES). In sum, the results presented here characterise the components of dACM, and in vitro studies were used to evaluate interactions of dACM with cell types important in wound healing.