The role of allogenic amniotic membrane in burn treatment

Allogeneic composite amniotic membrane in tympanic membrane repair: a randomized parallel controlled study

BACKGROUNDS

Composite amniotic membranes have been widely used in ophthalmology and orthopedics. For the repair of tympanic membrane perforation, the introduction of amniotic membrane is still under study.

OBJECTIVES

To analyse the effectiveness of a homograft composite amniotic membrane in tympanic membrane repair.

METHODS

A total of 76 patients were recruited and randomly assigned to the experimental group (n = 39) and the control group (n = 37). The test group employed a composite amniotic membrane for the repair of the tympanic membrane, while the control group utilized cartilage from the auricular for the same purpose. The efficacy of composite amniotic membrane was evaluated through a comparative analysis of postoperative tympanic membrane healing, complications, and hearing recovery.

RESULTS

Hearing improved significantly in both groups, but there was no significant difference between the two groups. The results of the postoperative pain scores demonstrated that the majority of patients were experiencing mild pain, with a notable discrepancy between the test group and the control group. Intraoperative bleeding time was also significantly lower in the test group than in the control group.

CONCLUSION

Allogeneic composite amniotic membrane can be used as a material for repairing tympanic membrane perforation, which can effectively improve postoperative hearing of patients.

Effects of human amniotic membrane on the angiogenesis and healing of ischemic wounds in a rat model

Although the human amniotic membrane (hAM) has been demonstrated to promote angiogenesis, its efficacy in healing ischemic wounds remains unknown. Therefore, the current study aimed to evaluate the potential of hAM as a dressing for treating ischemic wounds. The inferior abdominal wall arteries and veins of male rats were divided, and an ischemic wound was created on each side of the abdominal wall. Of the two ischemic wounds created, only one was covered with hAM, and its wound healing effect was determined by measuring the wound area. Angiogenesis was assessed by measuring microvessel density (MVD). On day 5, the mean wound area changed from 400 mm2 to 335.4 (260-450) mm2 in the hAM group and to 459 (306-570) mm2 in the control group (p = 0.0051). MVD was 19.0 (10.4-24.6) in the hAM group and 15.1 (10.6-20.8) in the control group (p = 0.0026). No significant differences in local pro- and anti-inflammatory cytokine levels were observed between the two groups. Histological examination revealed no rejection of the transplanted hAM. Therefore, the hAM may serve as a novel wound dressing that can promote angiogenesis and healing in ischemic wounds.

Characterization of Amnion-Derived Membrane for Clinical Wound Applications

Human amniotic membrane (hAM), the innermost placental layer, has unique properties that allow for a multitude of clinical applications. It is a common misconception that birth-derived tissue products, such as dual-layered dehydrated amnion-amnion graft (dHAAM), are similar regardless of the manufacturing steps. A commercial dHAAM product, Axolotl Biologix DualGraft™, was assessed for biological and mechanical characteristics. Testing of dHAAM included antimicrobial, cellular biocompatibility, proteomics analysis, suture strength, and tensile, shear, and compressive modulus testing. Results demonstrated that the membrane can be a scaffold for fibroblast growth (cellular biocompatibility), containing an average total of 7678 unique proteins, 82,296 peptides, and 96,808 peptide ion variants that may be antimicrobial. Suture strength results showed an average pull force of 0.2 N per dHAAM sample (equating to a pull strength of 8.5 MPa). Tensile modulus data revealed variation, with wet samples showing 5× lower stiffness than dry samples. The compressive modulus and shear modulus displayed differences between donors (lots). This study emphasizes the need for standardized processing protocols to ensure consistency across dHAAM products and future research to explore comparative analysis with other amniotic membrane products. These findings provide baseline data supporting the potential of amniotic membranes in clinical applications.

Decellularized Umbilical Cord as a Scaffold to Support Healing of Full-Thickness Wounds

The umbilical cord is a material that enhances regeneration and is devoid of age-related changes in the extracellular matrix (ECM). The aim of this work was to develop a biodegradable scaffold from a decellularized human umbilical cord (UC-scaffold) to heal full-thickness wounds. Decellularization was performed with 0.05% sodium dodecyl sulfate solution. The UC-scaffold was studied using morphological analysis methods. The composition of the UC-scaffold was studied using immunoblotting and Fourier transform infrared spectroscopy. The adhesion and proliferation of mesenchymal stromal cells were investigated using the LIVE/DEAD assay. The local reaction was determined by subcutaneous implantation in mice (n = 60). A model of a full-thickness skin wound in mice (n = 64) was used to assess the biological activity of the UC-scaffold. The proposed decellularization method showed its effectiveness in the umbilical cord, as it removed cells and retained a porous structure, type I and type IV collagen, TGF-β3, VEGF, and fibronectin in the ECM. The biodegradation of the UC-scaffold in the presence of collagenase, its stability during incubation in hyaluronidase solution, and its ability to swell by 1617 ± 120% were demonstrated. Subcutaneous scaffold implantation in mice showed gradual resorption of the product in vivo without the formation of a dense connective tissue capsule. Epithelialization of the wound occurred completely in contrast to the controls. All of these data suggest a potential for the use of the UC-scaffold.

The Collection and Application of Autologous Amniotic Fluid to Cesarean Delivery Closure

Background  Amniotic fluid and amnion membranes have been used in surgery specialties to improve wound healing and decrease surgical adhesion formation. Objective  The objective was to determine if amniotic fluid could be collected at cesarean delivery and then reapplied to the layers of the closure using the CeaLogic Specimen Collection and Ratio Applicator Kit. Study Design  Twenty pregnant individuals who met inclusion and exclusion criteria were enrolled. Amniotic fluid was collected at artificial rupture of the membranes using the collection kit. Autologous amniotic fluid was then transferred to the applicator kit, mixed with calcium chloride solution, and applied directly to each of the surgical repair layers during closure: closed hysterotomy incision, closed fascial incision, closed subcutaneous layer (if applicable), and closed skin. Subjects were then followed for six weeks. Photographs of the incision were taken immediately following surgery, one-week following surgery, and at the four-week postpartum visit. The Modified Hollander Cosmesis Score was used to assess wound appearance. Results  Twenty pregnant individuals who met inclusion and exclusion criteria were enrolled and all completed the study. The mean volume of amniotic fluid collected was 30 ± 19 mL. The median (IQR) Modified Hollander Cosmesis Score (Range 0-best, to 6-worst) at the one week and four-week postpartum visits was 0 (0,1) and 0 (0,2), respectively. There were no wound complications nor surgical site infections among the cohort. Further, there were no unscheduled visits for wound issues among any of the subjects. Conclusion  The CeaLogic Specimen Collection and Ratio Applicator Kits can be used to collect and reapply autologous amniotic fluid at the time of cesarean delivery. Future studies are needed to determine if the application of autologous amniotic fluid to cesarean delivery closure can improve cosmesis and wound healing, as well as decrease the risk for the development of intraabdominal adhesions.

Bilateral Crosslinking with Glutaraldehyde and 1-Ethyl-3-(3-Dimethylaminopropyl) Carbodiimide: An Optimization Strategy for the Application of Decellularized Human Amniotic Membrane in Tissue Engineering

Introduction

The decellularized human amniotic membrane (dHAM) emerges as a viable 3D scaffold for organ repair and replacement using a tissue engineering strategy. Glutaraldehyde (GTA) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) can increase the biomechanical properties of dHAM. However, the crosslinking process is associated with biochemical changes and residual toxic materials, dampening the biocompatibility of the dHAM. From a histologic point of view, each side of the amniotic membrane is biologically different. While the dHAM basement membrane side is rich in growth factors, the stromal side of the dHAM contains more connective tissue matrix (e.g., collagen fibers) which supports its biomechanical properties. Biocompatibility and biomechanical properties are two important challenges in the field of materials science. In this study, for the first time, the stromal and basement membrane side are cross-linked with GTA and EDC, respectively, to optimize the biocompatibility of the treated dHAM while sparing the GTA-mediated biomechanical improvements.

Methods

Crosslinking was carried out on dHAM in three groups: EDC, GTA and bilateral treatment with EDC>A. Mechanical resistance, degradability, and crosslinking measurements were performed on treated dHAM. The viability of mesenchymal stem cells (MSCs) on the scaffolds was evaluated by the MTT assay. The expression levels of surface markers and images of the MSCs were thoroughly studied.

Results

The results obtained showed that bilateral treatment of dHAM with EDC and GTA increased mechanical resistance. Similarly, the evaluation of surface markers revealed that bilaterally treated dHAM sustains the stemness and viability of MSCs at a level equal to that achieved with EDC alone. The SEM images indicated that the MSCs maintained adhesion on EDC>A-cross-linked dHAM.

Conclusion

The current study explores a pioneering treatment of dHAM, a material long recognized for its regenerative properties, in a novel context. This research delves into the utilization of dHAM cross-linked with EDC>A, demonstrating its optimized efficacy in tissue engineering. The enhanced crosslinking technique significantly alters the membrane's properties, amplifying its durability and therapeutic potential. In this novel bilateral treatment strategy (EDC and GTA), improving mechanical properties by GTA on the stromal surface and maintaining the biocompatibility of EDC on the side of the basement membrane of dHAM had been attained together. By investigating the handling and impact of this cross-linked membrane, this study unveils a new approach in leveraging a well-known material through an innovative process, revolutionizing its application in wound care.

Skin Substitutes and Autograft Techniques: Temporary and Permanent Coverage Solutions

Coverage of burn wounds is crucial to prevent sequalae including dehydration, wound infection, sepsis, shock, scarring, and contracture. To this end, numerous temporary and permanent options for coverage of burn wounds have been described. Temporary options for burn coverage include synthetic dressings, allografts, and xenografts. Permanent burn coverage can be achieved through skin substitutes, cultured epithelial autograft, ReCell, amnion, and autografting. Here, we aim to summarize the available options for burn coverage, as well as important considerations that must be made when choosing the best reconstructive option for a particular patient.

Human amniotic membranes as an allogenic biological dressing for the treatment of burn wounds: Protocol for a randomized-controlled study

Background

Burn wounds pose significant challenges in medical treatment due to their devastating nature and resource-intensive requirements. Temporary coverage of burn wounds using synthetic or biological dressings allows for reepithelization before definitive skin grafting. Allogenic skin grafts have been widely used but come with drawbacks such as rejection and disease transmission. The use of amniotic membranes (AMs) offers a promising alternative for temporary coverage, as they possess biological properties that promote faster healing and improved scar quality. The various components of the amniotic membrane, including pluripotent stem cells, extracellular matrix proteins, and regenerative factors, contribute to cell growth, migration, and differentiation, as well as preservation of the original epithelial phenotype.

Objective

Reliable information on the treatment of burn wounds with AM is needed. The knowledge gained in this project may help to include this advantageous modern concept of biological dressings in clinical practice. The purpose of this study is to use human amniotic membranes from our in hospital laboratory, as an allogenic biological dressing after enzymatic debridement in superficial partial thickness, deep partial thickness or full thickness burn wounds.

Methods

We will include 30 patients in a randomized-controlled trial with each patient receiving the study intervention and the control intervention. Two 7 × 7 cm burn wound areas will be compared regarding percentage of skin graft take, healing time, healing percentage value and total healing time. Human amniotic membranes will be compared to allogenic skin grafts.

Comparison effect of collagen/P3HB composite scaffold and human amniotic membrane loaded with mesenchymal stem cells on colon anastomosis healing in male rats

Covering surgical wounds with biomaterials, biologic scaffolds, and mesenchymal stem cells (MSCs) improves the healing process and reduces postoperative complications. This study was designed to evaluate and compare the effect of MSC-free/MSC-seeded new collagen/poly(3-hydroxybutyrate) (COL/P3HB) composite scaffold and human amniotic membrane (HAM) on the colon anastomosis healing process. COL/P3HB scaffold was prepared using freeze-drying method. MSCs were isolated and characterized from rat adipose tissue. After biocompatibility evaluation by MTT assay, MSCs were seeded on the scaffold and HAM by micro-mass seeding technique. In total, 35 male rats were randomly divided into five groups. After the surgical procedure, cecum incisions were covered by the MSC-free/MSC-seeded scaffold or HAM. Incisions in the control group were only sutured. One month later, the healing process was determined by stereological analysis. The Kruskal-Wallis followed by Dunn's tests were utilized for statistical outcome analysis (SPSS software version 21). COL/10% P3HB scaffold showed the best mechanical and structural properties (7.86 MPa strength, porosity more than 75%). MTT assay indicated that scaffold and especially HAM have suitable biocompatibility. Collagenization and neovascularization were significantly higher, and necrosis was considerably lower in all treated groups in comparison with the controls. MSC-seeded scaffold and HAM significantly decrease inflammation and increase gland volume compared with other groups. The MSC-seeded HAM was significantly successful in decreasing edema compared with other groups. Newly synthesized COL/P3HB scaffold improves the colon anastomosis healing; however, the major positive effect belonged to HAM. MSCs remarkably increase their healing process. Further investigations may contribute to confirming these results in other wound healing.

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.

A Prospective Multicenter Study of a Weekly Application Regimen of Viable Human Amnion Membrane Allograft in the Management of Nonhealing Diabetic Foot Ulcers

Background

Diabetic foot ulcers (DFUs) pose a significant clinical challenge for providers and patients, and often precede devastating complications such as infection, hospitalization, and amputation. Therefore, advanced treatment options are needed to facilitate the healing of chronic DFUs and improve outcomes in this high-risk population. Cryopreserved viable human amnion membrane allograft (vHAMA) has shown great promise in the treatment of recalcitrant DFUs as a supplement to standard of care (SOC). Placental grafts are rich in extracellular matrix proteins, growth factors, and cytokines, which can induce angiogenesis and dermal fibroblast proliferation, resulting in accelerated healing.

Methods

In this prospective, multicenter single arm trial, 20 patients with nonhealing DFUs received weekly application of vHAMA, in addition to SOC, for up to 12 weeks. The primary study endpoint was proportion of healed wounds at 12 weeks. Secondary endpoints included proportion of wounds healed at 6 weeks, time to heal, and percentage area wound reduction. Subjects were evaluated for ulcer healing and assessed for adverse events at every treatment visit.

Results

At study conclusion, 85% of patients receiving vHAMA healed. Ten wounds healed (50%) by 6 weeks, and 17 wounds (85%) healed by 12 weeks. The mean time to heal was 46.6 days (95% CI: 35.1-58.0), and the average number of vHAMAs used was 5.4 (SD: 3.25). The mean PAR was 86.3% (SD: 40.51).

Conclusions

Aseptically processed, cryopreserved vHAMA should be considered as a safe and effective option for DFUs refractory to SOC therapy.

Revisiting the Role of Amniotic Membrane Dressing in Acute Large Traumatic Wounds: A Randomized Feasibility Study at a Level 1 Trauma Centre

Introduction

Acute large traumatic wounds require temporary dressing prior to the definitive soft tissue reconstruction, as the physiological derangement during the immediate postinjury period delays the definitive surgical intervention. Selecting an ideal dressing material from numerous available synthetic dressings and skin substitutes poses a challenge. Although amniotic membrane (AM) scaffold has a definitive role in promoting wound healing in burns and chronic wounds, however, its efficacy in acute large traumatic wound is lacking. The present trial aimed to evaluate the safety and efficacy of AM in wound bed preparation before the definitive soft-tissue reconstruction in acute large traumatic wounds.

Methods

Sixty patients with acute large traumatic wounds (>10 cm × 10 cm) were divided into two groups (conventional dressing and AM dressing) using simple mixed block randomization. Wounds were assessed using the Bates Jensen Score at various timelines for the signs of early wound healing. The primary outcome was to evaluate the time taken for the wound bed preparation for definitive soft-tissue reconstruction. The secondary outcome was the pain assessment and complications, if any.

Results

There was significant reduction in the wound exudate as well as peripheral tissue edema in the intervention group (P = 0.01). AM dressing was significantly less painful (P = 0.01). The incidence of wound infection and need for debridement was decreased in the intervention group. However, the time interval to definitive soft-tissue coverage was statistically insignificant and comparable in both the groups. No adverse reactions were seen in either group.

Conclusion

AM dressings are safe and efficacious with significant reduction in wound exudates and peripheral edema. However, these dressings do not hasten the wound maturation as compared to conventional dressings. AM dressings can be used as a less painful alternative to conventional dressing in the management of large acute posttraumatic wounds.

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

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

Burn Care in Low-Resource and Austere Settings

More than 95% of the 11 million burns that occur annually happen in low-resource settings, and 70% of those occur among children. Although some low- and middle-income countries have well-organized emergency care systems, many have not prioritized care for the injured and experience unsatisfactory outcomes after burn injury. This chapter outlines key considerations for burn care in low-resource settings.

Amnion membranes support wound granulation in a delayed murine excisional wound model

Chronic or delayed healing wounds constitute an ever-increasing burden on healthcare providers and patients alike. Thus, therapeutic modalities that are tailored to particular deficiencies in the delayed wound healing response are of critical importance to improve clinical outcomes. Human amnion-derived viable and devitalized allografts have demonstrated clinical efficacy in promoting the closure of delayed healing wounds, but the mechanisms responsible for this efficacy and the specific wound healing processes modulated by these tissues are not fully understood. Here, we utilized a diabetic murine excisional wound model in which healing is driven by granulation and re-epithelialization, and we applied viable (vHAMA) or devitalized (dHAMA) amnion-derived allografts to the wound bed in order to determine their effects on wound healing processes. Compared to control wounds that were allowed to heal in the absence of treatment, wounds to which vHAMA or dHAMA were applied demonstrated enhanced deposition of granulation tissue accompanied by increased cellular proliferation and increased de novo angiogenesis, while vHAMA-treated wounds also demonstrated accelerated re-epithelialization. Taken together, these data suggest that both vHAMA and dHAMA facilitate wound healing through promoting processes critical to granulation tissue formation. Further understanding of the cellular and tissue mechanisms underlying the effects of tissue-derived matrices on wound healing will enable tailored prescription of their use in order to maximize clinical benefit.

Initial Clinical Outcomes Using Umbilical Cord-Derived Tissue Grafts to Repair Anovaginal Fistula

BACKGROUND

Perianal fistula is a debilitating disease and challenging condition to treat. Recently, the use of stem cells has been shown to improve healing of fistulas.

OBJECTIVE

The aim was to examine the use of an umbilical cord-derived stem cell graft in a pilot study as a novel scaffold/stem inlay implanted into fistula repairs for anovaginal fistula to examine healing rates.

DESIGN

This was a pilot study.

SETTINGS

This study took place in a colorectal surgery practice.

PATIENTS

Patients with anovaginal fistula consented to participate. Cryopreserved umbilical cord tissue graft with viable cells was incorporated as an inlay using a previously reported technique by the authors. Demographic data including history of previous repairs and IBD were included. All patients were followed for a minimum of 6 weeks.

MAIN OUTCOME MEASURES

The primary measures were safety and efficacy of novel stem cell graft in the treatment of anovaginal fistula.

RESULTS

From September 2017 to September 2019, 15 patients underwent anovaginal fistula repair. Three of these patients underwent a second repair, for a total of 18 repairs. No patient was intentionally diverted, but 3 patients presented for repair with a preexisting stoma. The majority of repairs were previous repair failures (12; 67%), and 7 repairs were performed on 5 patients with IBD. Median follow-up was 30 (6-104) weeks. The safety profile for cryopreserved umbilical cord tissue graft was excellent as no adverse events occurred. Overall complete healing rate was 39%, and 12 (67%) repairs resulted in improvement of symptoms.

LIMITATIONS

This was a small pilot study.

CONCLUSIONS

This is the largest series using cryopreserved umbilical cord graft for anovaginal fistula repair. The use of umbilical cord was safe and effective at closing defects. Randomized studies are necessary to determine added benefits over current standard of care. See Video Abstract at http://links.lww.com/DCR/B896 .

RESULTADOS CLNICOS INICIALES DEL USO DE INJERTOS DE TEJIDO DERIVADO DE PLACENTA PARA REPARACIN DE FSTULAS ANOVAGINALES

ANTECEDENTES:La fístula perianal es una enfermedad debilitante y una afección difícil de tratar. Recientemente, se ha demostrado que el uso de células madre mejora la curación de las fístulas.OBJETIVO:Deseamos examinar el uso de un injerto de células madre derivadas de cordón umbilical en un estudio piloto como una nueva matriz/injerto de células madre implantado en reparaciones de fístula para fístula anovaginal para examinar las tasas de curación.DISEÑO:Este fue un estudio piloto.ESCENARIO:Este estudio se llevó a cabo en una clínica de cirugía colorrectal.PACIENTES:Se obtuvo consentimiento informado de pacientes con fístula anovaginal. El injerto de tejido de cordón umbilical criopreservado con células viables se incorporó como incrustación utilizando una técnica previamente informada por los autores. Se incluyeron datos demográficos que incluían antecedentes de reparaciones previas y enfermedad inflamatoria intestinal. Todos los pacientes fueron seguidos durante un mínimo de 6 semanas.PRINCIPALES MEDIDAS DE RESULTADO:Las principales medidas fueron la seguridad y la eficacia del nuevo injerto de células madre en el tratamiento de la fístula anovaginal.RESULTADOS:Desde 9/2017-9/2019, 15 pacientes fueron sometidas a reparación de fístula anovaginal. Tres de estos pacientes fueron sometidos a una segunda reparación, para un total de 18 reparaciones. Ningún paciente fue derivado intencionalmente mientras que 3 pacientes se presentaron para reparación con un estoma preexistente. La mayoría de las reparaciones fueron fallas de reparaciones previas (12, 67%) y se realizaron siete reparaciones en 5 pacientes con enfermedad inflamatoria intestinal (EII). La mediana de seguimiento fue de 30 semanas (6-104). El perfil de seguridad del injerto de tejido de cordón umbilical criopreservado fue excelente ya que no se produjeron efectos adversos. La tasa general de curación completa fue del 39% y 12 (67%) reparaciones dieron como resultado una mejoría de los síntomas.LIMITACIONES:Este fue un pequeño estudio piloto.CONCLUSIÓNES:Ésta es la serie más grande de utilización de injerto de cordón umbilical criopreservado para la reparación de una fístula anovaginal. La utilización del cordón umbilical resultó segura y eficaz para cerrar defectos. Se necesitan estudios aleatorizados para determinar los beneficios adicionales sobre el estándar de atención actual. Consulte Video Resumen en http://links.lww.com/DCR/B896 . (Traducción-Dr. Jorge Silva Velazco ).

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

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

Immune Tolerance of Embryo Implantation and Pregnancy: The Role of Human Decidual Stromal Cell- and Embryonic-Derived Extracellular Vesicles

Embryo–endometrial communication plays a critical role in embryo implantation and the establishment of a successful pregnancy. Successful pregnancy outcomes involve maternal immune modulation during embryo implantation. The endometrium is usually primed and immunomodulated by steroid hormones and embryo signals for subsequent embryo implantation and the maintenance of pregnancy. The roles of extracellular vesicles (EVs) and microRNAs for the embryo–maternal interactions have been elucidated recently. New evidence shows that endometrial EVs and trophectoderm-originated EV cargo, including microRNAs, proteins, and lipids in the physiological microenvironment, regulate maternal immunomodulation for embryo implantation and subsequent pregnancy. On the other hand, trophoblast-derived EVs also control the cross-communication between the trophoblasts and immune cells. The exploration of EV functions and mechanisms in the processes of embryo implantation and pregnancy will shed light on a practical tool for the diagnostic or therapeutic approaches to reproductive medicine and infertility.

The Role of Skin Substitutes in Acute Burn and Reconstructive Burn Surgery: An Updated Comprehensive Review

Burns disrupt the protective skin barrier with consequent loss of cutaneous temperature regulation, infection prevention, evaporative losses, and other vital functions. Chronically, burns lead to scarring, contractures, pain, and impaired psychosocial well-being. Several skin substitutes are available and replace the skin and partially restore functional outcomes and improve cosmesis. We performed a literature review to update readers on biologic and synthetic skin substitutes to date applied in acute and reconstructive burn surgery. Improvement has been rapid in the development of skin substitutes in the last decade; however, no available skin substitute fulfills criteria as a perfect replacement for damaged skin.

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.

Healing Effects of Human Amniotic Membrane and Burned Wool on the Second-degree Burn in Rats

Background:

This study aimed to compare sheep burnt wool and human amniotic membrane (AM) on second-degree burn wound healing in rats.

Materials and Methods:

Seventy-two adult male rats of Sprague Dawley underwent general anesthesia, and a deep second-degree burn was created on their skin by a hot iron plate. Afterward, human AM, silver sulfadiazine ointment (SSD), and sheep burned wool were used on wound area for burn treatment. On days 7, 14, and 21 of the experiment, the rats were sacrificed, and histopathological assessments were done.

Results:

Human AM, in comparison with other groups, significantly (P<0.05) showed better improvement in all pathologic variables. Burned wool showed significant improvement compared to the control group on day 7 in the angiogenesis, on day 14 in granulation tissue formation and epithelial formation, and on day 21 in new epithelial formation (P<0.05). Burned wool compared with SSD ointment in granulation tissue formation improved significantly (P<0.05) on days 7 and 14. Also, SSD ointment in comparison with the control group significantly improved (P<0.05) granulation tissue formation and macrophage on day 7.

Conclusion:

Human AM has a significant effect on the treatment of second-degree burn. Burned wool has a better effect on wound healing than SSD ointment and negative control group without treatment in terms of granulation tissue and epithelium formation.

Using Dry Human Amniotic Membrane in Secondary Intention Wound Healing After Urological Cancer Surgery: The First Randomized Clinical Trial in Iran

Background: Wound healing is a complex process and in some patients, it is a long process. Due to the presence of various underlying diseases in patients with cancer, this process is delayed, and as a result, the rate of complications increases. Therefore, some materials are needed to accelerate wound healing. Nowadays efficacy of dry human amniotic membrane in burn wounds and chronic wounds is proven; however, no studies have been performed on the effect of this tissue in the treatment of surgical wounds. Objectives: This study aimed at evaluating the efficacy of dry human amniotic membrane in the secondary repair of urological cancer surgery wounds. Methods: In this randomized clinical trial from January 2018 to June 2020, 40 patients who underwent urological cancer surgery and secondary intention wound healing were selected and randomly divided into 2 groups of 20 patients. In the case group, the dry human amniotic membrane was used for dressing wounds, and in the control group, normal dressing without an amniotic membrane was performed. Complications such as infection, sepsis, and reoperation, as well as the duration of wound healing and hospitalization of patients at intervals of 1 week, 1, and 3 months, were compared between the 2 groups. Results: The 2 groups matched in terms of gender, age, and wound location. The mean duration of hospitalization and wound healing was significantly lower in the case group (P < 0.05). The rate of complications was higher in the control group but was not significant. Conclusions: Dry human amniotic membranes due to the accelerated wound healing process and fewer complications could be a good choice for secondary healing of wounds after urological cancer surgery.

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

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

Closure of the radial forearm free flap donor site with split-thickness skin graft or amniotic membrane: A prospective randomized clinical study

The purpose of this study was to compare the clinical, aesthetic, and functional outcomes between amniotic membrane (test group) and split-thickness skin grafts (control group) used for radial forearm free flap defect closure. The primary outcome measurement for both groups was assessment of the defect closure healing process. In addition, aesthetic (Vancouver Scar Scale) and functional outcomes (skin sensitivity, hand/wrist functionality, grip strength) were evaluated. Fifty eligible patients with radial forearm free flap donor site defects were randomly assigned to two groups receiving either amniotic membrane (test group; n = 25) or split-thickness skin graft (control group; n = 25) for defect covering. Forty-seven of the 50 patients (n = 47) were able to be followed up for 6 months and showed a significantly longer healing process (p < 0.001) with amniotic membrane (64.5 ± 38.4 days; n = 24) than with split-thickness skin grafts (29.2 ± 8.9 days; n = 23); however, there were no differences in the prevalence of healing defects/dehiscence and/or wound infections. Forty-two of the 47 patients (21 in each group) were able to be continually followed up for 12 months, and showed no differences in terms of clinical outcome as well as the subjective and objective aesthetic and functional results evaluated. With regard to the clinical, aesthetic, and functional outcomes evaluated for radial forearm free flap defects, coverage with amniotic membrane offers an excellent alternative treatment approach, avoiding secondary induced donor site morbidity.

Exosomes Secreted from Amniotic Membrane Contribute to Its Anti-Fibrotic Activity

Amniotic membranes (AM) have anti-fibrotic activity. Exosomes (nano-sized vesicles) function as conduits for intercellular transfer and contain all the necessary components to induce the resolution of fibrosis. In this study, we tested the hypothesis that the anti-fibrotic activity of AM is mediated by exosomes. AM-derived exosomes or amniotic stromal cell-derived exosomes were isolated and characterized. Anti-fibrotic activity of exosomes was evaluated using human hepatic stellate cells (LX-2), an in vitro model of fibrosis. Exosomes isolated from AM tissue-conditioned media had an average size of 75 nm. Exosomes significantly inhibited the proliferation of TGFβ1-activated LX-2 but had no effect on the proliferation of non-activated LX-2 cells. Exosomes also reduced the migration of LX-2 in a scratch wound assay. Furthermore, exosomes reduced the gene expression of pro-fibrotic markers such as COL1A1, ACTA, and TGFβ1 in LX-2 cells. Interestingly, exosomes isolated from AM tissue under hypoxic conditions seemed to show a stronger anti-fibrotic activity than exosomes isolated from tissue under normoxic conditions. Exosomes released by in vitro cultured AM stromal cells were smaller in size compared with tissue exosomes and also showed anti-fibrotic activity on LX-2 cells. In conclusion, AM-tissue-released exosomes contribute to the anti-fibrotic activity of AM. This is the first report of isolation, characterization, and functional evaluation of exosomes derived from amniotic tissues with the direct comparison between tissue-derived exosomes and cultured cell-derived exosomes.

Validation of Three Different Sterilization Methods of Tilapia Skin Dressing: Impact on Microbiological Enumeration and Collagen Content

Tilapia fish skin has demonstrated promise as a stable and practical biological dressing to be used in wound and burn management. However, the appropriate sterilization technique of the Tilapia fish skin is crucial before its clinical application. The standard sterilization technique must eliminate harmful pathogens but maintain the structural and biochemical properties that could compromise the dressing function. This study investigated and compared the efficiency of three sterilizing agents; chlorhexidine gluconate 4% (CHG), povidone iodine 10% (PVP-I), and silver nanoparticles (25 μg/mL) (AgNPs), at three different times (5, 10, and 15 min) on Tilapia fish skin based on the microbial count, histological and collagen properties. Among the sterilization procedures, AgNPs showed rapid and complete antimicrobial activity, with a 100% reduction in microbial growth of the fish skin throughout the treated times. Furthermore, AgNPs did not impair the cellular structure or collagen fibers content of the fish skin. However, CHG and PVP-I caused alterations in the collagen content. This study demonstrated that the AgNPs treatment of Tilapia fish skin provided sterile skin while preserving the histological properties and structural integrity. These findings provide an efficient and quick sterilization method suitable for Tilapia fish skin that could be adopted as a biological dressing.

Electrospun polycaprolactone (PCL)-amnion nanofibrous membrane prevents adhesions and promotes nerve repair in a rat model of sciatic nerve compression

Adhesion and scarring after neural surgery are detrimental to nerve regeneration and functional recovery. Amniotic membranes have been used in tissue repair due to their immunogenicity and richness in cytokines. In this study, an electrospun polycaprolactone (PCL)-amnion nanofibrous membrane was prepared for the treatment of sciatic nerve compression in a rat model. The effects of the PCL-amnion nanofibrous membrane on the prevention of adhesion formation and nerve regeneration were evaluated using electrophysiology and histological analyses. Compared with the medical chitosan hydrogel dressing, the PCL-amnion nanofibrous membrane significantly reduced peripheral nerve adhesion and promoted the rapid recovery of nerve conduction. Moreover, the immunohistochemical analysis identified more Schwann cells and less pro-inflammatory M1 macrophages in the PCL-amnion group. Western blot and RT-PCR results showed that the expression levels of type-Ⅰ and Ⅲ collagen in the PCL-treated rats were half of those in the control group after 12 weeks, while the expression level of nerve growth factor was approximately 3.5 times that found in the rats treated with medical chitosan hydrogel. In summary, electrospun PCL-amnion nanofibrous membranes can effectively reduce adhesion after neural surgery and promote nerve repair and regeneration. The long-term retention in vivo and sustained release of cytokines make PCL-amnion a promising biomaterial for clinical application.

Topical treatment for facial burns

BACKGROUND

Burn injuries are an important health problem. They occur frequently in the head and neck region. The face is the area central to a person's identity that provides our most expressive means of communication. Topical interventions are currently the cornerstone of treatment of burns to the face.

OBJECTIVES

To assess the effects of topical interventions on wound healing in people with facial burns of any depth.

SEARCH METHODS

In December 2019 we searched the Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE (including In-Process & Other Non-Indexed Citations); Ovid Embase and EBSCO CINAHL Plus. We also searched clinical trials registries for ongoing and unpublished studies, and scanned reference lists of relevant included studies as well as reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that evaluated the effects of topical treatment for facial burns were eligible for inclusion in this review.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, data extraction, risk of bias assessment and GRADE assessment of the certainty of the evidence.

MAIN RESULTS

In this first update, we included 12 RCTs, comprising 507 participants. Most trials included adults admitted to specialised burn centres after recent burn injuries. Topical agents included antimicrobial agents (silver sulphadiazine (SSD), Aquacel-Ag, cerium-sulphadiazine, gentamicin cream, mafenide acetate cream, bacitracin), non-antimicrobial agents (Moist Exposed Burn Ointment (MEBO), saline-soaked dressings, skin substitutes (including bioengineered skin substitute (TransCyte), allograft, and xenograft (porcine Xenoderm), and miscellaneous treatments (growth hormone therapy, recombinant human granulocyte-macrophage colony-stimulating factor hydrogel (rhGMCS)), enzymatic debridement, and cream with Helix Aspersa extract). Almost all the evidence included in this review was assessed as low or very low-certainty, often because of high risk of bias due to unclear randomisation procedures (i.e. sequence generation and allocation concealment); lack of blinding of participants, providers and sometimes outcome assessors; and imprecision resulting from few participants, low event rates or both, often in single studies. Topical antimicrobial agents versus topical non-antimicrobial agents There is moderate-certainty evidence that there is probably little or no difference between antimicrobial agents and non-antimicrobial agents (SSD and MEBO) in time to complete wound healing (hazard ratio (HR) 0.84 (95% confidence interval (CI) 0.78 to 1.85, 1 study, 39 participants). Topical antimicrobial agents may make little or no difference to the proportion of wounds completely healed compared with topical non-antimicrobial agents (comparison SSD and MEBO, risk ratio (RR) 0.94, 95% CI 0.68 to 1.29; 1 study, 39 participants; low-certainty evidence). We are uncertain whether there is a difference in wound infection (comparison topical antimicrobial agent (Aquacel-Ag) and MEBO; RR 0.38, 95% CI 0.12 to 1.21; 1 study, 40 participants; very low-certainty evidence). No trials reported change in wound surface area over time or partial wound healing. There is low-certainty evidence for the secondary outcomes scar quality and patient satisfaction. Two studies assessed pain but it was incompletely reported. Topical antimicrobial agents versus other topical antimicrobial agents It is uncertain whether topical antimicrobial agents make any difference in effects as the evidence is low to very low-certainty. For primary outcomes, there is low-certainty evidence for time to partial (i.e. greater than 90%) wound healing (comparison SSD versus cerium SSD: mean difference (MD) -7.10 days, 95% CI -16.43 to 2.23; 1 study, 142 participants). There is very low-certainty evidence regarding whether topical antimicrobial agents make a difference to wound infection (RR 0.73, 95% CI 0.46 to 1.17; 1 study, 15 participants). There is low to very low-certainty evidence for the proportion of facial burns requiring surgery, pain, scar quality, adverse effects and length of hospital stay. Skin substitutes versus topical antimicrobial agents There is low-certainty evidence that a skin substitute may slightly reduce time to partial (i.e. greater than 90%) wound healing, compared with a non-specified antibacterial agent (MD -6.00 days, 95% CI -8.69 to -3.31; 1 study, 34 participants). We are uncertain whether skin substitutes in general make any other difference in effects as the evidence is very low certainty. Outcomes included wound infection, pain, scar quality, adverse effects of treatment and length of hospital stay. Single studies showed contrasting low-certainty evidence. A bioengineered skin substitute may slightly reduce procedural pain (MD -4.00, 95% CI -5.05 to -2.95; 34 participants) and background pain (MD -2.00, 95% CI -3.05 to -0.95; 34 participants) compared with an unspecified antimicrobial agent. In contrast, a biological dressing (porcine Xenoderm) might slightly increase pain in superficial burns (MD 1.20, 95% CI 0.65 to 1.75; 15 participants (30 wounds)) as well as deep partial thickness burns (MD 3.00, 95% CI 2.34 to 3.66; 10 participants (20 wounds)), compared with antimicrobial agents (Physiotulle Ag (Coloplast)). Miscellaneous treatments versus miscellaneous treatments Single studies show low to very low-certainty effects of interventions. Low-certainty evidence shows that MEBO may slightly reduce time to complete wound healing compared with saline soaked dressing (MD -1.7 days, 95% CI -3.32 to -0.08; 40 participants). In addition, a cream containing Helix Aspersa may slightly increase the proportion of wounds completely healed at 14 days compared with MEBO (RR 4.77, 95% CI 1.87 to 12.15; 43 participants). We are uncertain whether any miscellaneous treatment in the included studies makes a difference in effects for the outcomes wound infection, scar quality, pain and patient satisfaction as the evidence is low to very low-certainty.

AUTHORS' CONCLUSIONS

There is mainly low to very low-certainty evidence on the effects of any topical intervention on wound healing in people with facial burns. The number of RCTs in burn care is growing, but the body of evidence is still hampered due to an insufficient number of studies that follow appropriate evidence-based standards of conducting and reporting RCTs.

Comparison between Cryopreserved and Dehydrated Human Amniotic Membrane Graft in Treating Challenging Cases with Macular Hole and Macular Hole Retinal Detachment

Purpose

To evaluate the surgical outcomes of cryopreserved and dehydrated human amniotic membrane (hAM) graft transplantation for macular hole (MH) and macular hole retinal detachment (MHRD) repair.

Materials and Methods

This retrospective, interventional case series was conducted in two hospitals. Two types of hAM grafts, namely, the dehydrated form (AmnioGen, HCT Regenerative, Taiwan) and the cryopreserved form (AmnioGraft, Bio-Tissue, Miami, FL), were consecutively used in MH surgeries. Anatomical and functional outcomes between the 2 types of hAM grafts were compared.

Results

Seventeen patients (mean age: 62.1 ± 10.0 years, 9 (52.9%) males) were enrolled. Of them, 11 patients had persistent MH, 3 had MH without prior surgery, and 3 had MHRD. A cryopreserved hAM graft was used in 10 patients, and a dehydrated hAM graft was used in 8 patients. One patient used a cryopreserved hAM in the first MH surgery and a dehydrated hAM in the second surgery for extramacular hole with retinal detachment. After a 6-month follow-up, 13 (76.5%) patients had sealed MHs. The average visual acuity (VA) of cases with sealed MHs improved from 1.38 ± 0.62 to 1.12 ± 0.47 logMAR (p=0.03). In the other 4 cases with persistent MH, 3 had graft dislocation and 1 had a reopened MH with graft contraction. There were no significant differences in closure rate (80.00% vs. 71.43%, p=0.68) or VA improvement (0.19 ± 0.37 logMAR vs. 0.15 ± 0.41 logMAR, p=0.85) between the 2 kinds of hAM graft.

Conclusion

This preliminary case series showed that both cryopreserved hAM and dehydrated hAM are feasible alternative grafts for either persistent or recurrent MH. Both approaches have similar anatomical and functional outcomes.

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.

Preparation of placental tissue transplants and their application in skin wound healing and chosen skin bullous diseases - Stevens-Johnson syndrome and toxic epidermal necrolysis treatment

Unique properties of amniotic membrane make it a promising source for tissue engineering and a clinically useful alternative for patients suffering from chronic wounds including, for example, ulcers, burns, ocular surface damages and wounds occurring in the course of bullous diseases like stevens-johnson syndrome and toxic epidermal necrolysis. Its use has many advantages over standard wound care, as it contains pluripotent cells, nutrients, anti-fibrotic and anti-inflammatory cytokines, growth factors and extracellular matrix (ECM) proteins. Placental tissues can be prepared as a medical component, an advanced therapy medicinal product or a tissue graft. In addition to basic preparation procedures such as washing, rinsing, cutting, drying and sterilisation, there are many optional steps such as perforation, crosslinking and decellularisation. Finally, transplants should be properly stored-in cryopreserved or dehydrated form. In recent years, many studies including basic science and clinical trials have proven the potential to expand the use of amniotic membrane and amnion-derived cells to the fields of orthopaedics, dentistry, surgery, urology, vascular tissue engineering and even oncology. In this review, we discuss the role of placental tissues in skin wound healing and in the treatment of various diseases, with particular emphasis on bullous diseases. We also describe some patented procedures for placental tissue grafts preparation.

Amnion membrane hydrogel and amnion membrane powder accelerate wound healing in a full thickness porcine skin wound model

There is a need for effective wound treatments that retain the bioactivity of a cellular treatment, but without the high costs and complexities associated with manufacturing, storing, and applying living biological products. Previously, we developed an amnion membrane-derived hydrogel and evaluated its wound healing properties using a mouse wound model. In this study, we used a full thickness porcine skin wound model to evaluate the wound-healing efficacy of the amnion hydrogel and a less-processed amnion product comprising a lyophilized amnion membrane powder. These products were compared with commercially available amnion and nonamnion wound healing products. We found that the amnion hydrogel and amnion powder treatments demonstrated significant and rapid wound healing, driven primarily by new epithelialization versus closure by contraction. Histological analysis demonstrated that these treatments promote the formation of a mature epidermis and dermis with similar composition to healthy skin. The positive skin regenerative outcomes using amnion hydrogel and amnion powder treatments in a large animal model further demonstrate their potential translational value for human wound treatments.

Allogeneic mesenchymal stem cells for treatment of severe burn injury

The most important determinant of survival post-burn injury is wound healing. For decades, allogeneic mesenchymal stem cells (MSCs) have been suggested as a potential treatment for severe burn injuries. This report describes a patient with a severe burn injury whose wounds did not heal with over 18 months of conventional burn care. When treated with allogeneic MSCs, wound healing accelerated with no adverse treatment complications. Wound sites showed no evidence of keloids or hypertrophic formation during a 6-year follow-up period. This therapeutic use of allogeneic MSCs for large non-healing burn wounds was deemed safe and effective and has great treatment potential.

Use of amniotic membrane for radial forearm free flap donor site coverage: clinical, functional and cosmetic outcomes

Objective

To evaluate the clinical, functional and aesthetic outcomes for radial forearm free flap (RFFF) donor sites covered with amniotic membrane (AM).

Material and methods

The healing process of patients with RFFF donor sites covered with AM was prospectively followed for 1 year. Additionally at the 12-month evaluation, objective scoring systems were used to assess the aesthetic (Vancouver scar scale, VSS: range 1–13) and functional outcome (skin sensibility, hand/wrist functionality [goniometer], grip strength [score 1 = excellent, 5 = poor]). By using a subjective rating system (score 1 = excellent, 5 = poor), the patient-reported aesthetic and functionality outcome was correlated with objective data analysis.

Results

Twenty-one out of 23 patients were followed for 12 months (dropout: 2 patients at 3 months). In 17/23 (73.9%) patients RFFF defect covered with AM showed an uneventful healing period (< 3 months). Prolonged healing periods (> 3 months < 6) for 6 patients (26.1%) were attributed to wound infections (4×), seroma (1×) and inflammation (1×). At the 1-year evaluation, there was a significant (p < 0.01) correlation between subjective (2.0 ± 0.71) and objective aesthetic scores (VVS 3.74 ± 2.18), and a successful grip strength (score 1.67 ± 0.86); however, thumb hyposensibility in 76.2% was seen. A high body mass index (BMI) was in conjunction with a negative (p = 0.012) and the use of antihypertensive medications provided positive effects (p = 0.041) on the aesthetic outcome.

Conclusion

RFFF donor site defects covered using AM show excellent clinical, aesthetic and functional outcome representing patient comorbidities (BMI, antihypertensive drugs) might affect the aesthetic outcome.

Clinical relevance

In relation to the excellent outcomes found, the use of AM offers an alternative treatment procedure for RFFF defect covering.

Efficient Wound Healing Using a Synthetic Nanofibrous Bilayer Skin Substitute in Murine Model

Treatment of full-thickness skin wounds with minimal scarring and complete restoration of native tissue properties still exists as a clinical challenge. A bilayer skin substitute was fabricated by coating human amniotic membrane (AM) with electrospun silk fibroin nanofibers, and its in vivo biological behavior was studied using murine full-thickness skin wound model. Donut-shaped silicon splints were utilized to prevent wound contraction in mouse skin and simulate re-epithelialization, which is the normal path of human wound healing. Skin regeneration using the bilayer scaffold was compared with AM and untreated defect after 30 d. Tissue samples were taken from healed wound areas and investigated through histopathological and immunohistochemical staining to visualize involucrin (IVL), P63, collagen I, CD31, and vascular endothelial growth factor. In addition, mRNA expression of IVL, P63, interleukin-6, and cyclooxygenase-2 was studied. The application of bilayer scaffold resulted in the best epidermal and dermal regeneration, demonstrated by histopathological examination and molecular analysis. In regenerated wounds of the bilayer scaffold group, the mRNA expression levels of inflammatory markers (interleukin-6 and cyclooxygenase-2) were downregulated, and the expression pattern of keratinocyte markers (IVL and P63) at both mRNA and protein levels was more similar to native tissue in comparison with AM and no-treatment groups. There was no significant difference in the expression level of collagen I, CD31, and vascular endothelial growth factor among different groups. Conclusively, these promising results serve as a supporting evidence for proceeding to clinical phase to examine the capacity of this bilayer scaffold for human skin regeneration.

Endogenous viable cells in lyopreserved amnion retain differentiation potential and anti-fibrotic activity in vitro

Human amniotic membrane (AM) has intrinsic anti-inflammatory, anti-fibrotic and antimicrobial properties. Tissue preservation methods have helped to overcome the short shelf life of fresh AM allowing "on demand" use of AM grafts. Cryopreserved AM that retains all native tissue components, including viable cells, has clinical benefits in treating chronic wounds. However, cryopreservation requires ultra-low temperature storage, limiting the use of cryopreserved products. To overcome this limitation, a new lyopreservation method has been developed for ambient storage of living tissues. The goal of this study was to investigate the viability and functionality of AM cells following lyopreservation. Fresh AM and devitalized lyopreserved AM (DLAM) served as positive and negative controls, respectively. Using live/dead staining, we confirmed the presence of living cells in viable lyopreserved AM (VLAM) and showed that these cells persisted up to 21 days in culture medium. The functionality of cells in VLAM was assessed by their differentiation potential and anti-fibrotic activity in vitro. With osteogenic induction, cells in VLAM deposited calcium within the membrane, a marker of osteogenic cells, in a time-dependent manner. The migration of human lung fibrotic fibroblasts in a scratch wound assay was reduced significantly in the presence of VLAM-derived conditioned medium. Quantitative PCR analyses indicated that VLAM reduced the expression of pro-fibrotic factors such as type I collagen and increased the expression of anti-fibrotic factors such as hepatocyte growth factor and anti-fibrotic microRNA in fibrotic fibroblasts. Taken together, these results demonstrate that endogenous cells in VLAM remain viable and functional post-lyophilization. STATEMENT OF SIGNIFICANCE: This study, for the first time, provides direct evidence showing that tissue viability and functional cells can be preserved by lyophilization. Similar to fresh amniotic membrane (AM), viable lyopreserved AM (VLAM) retains viable cells for extended periods of time. More importantly, these cells are functional and maintain their osteogenic differentiation potential and anti-fibrotic activity. Our results confirmed that the novel lyophilization method preserves tissue viability.

Use of cryopreserved umbilical cord with negative pressure wound therapy for complex diabetic ulcers with osteomyelitis

OBJECTIVE

The objective of this study was to evaluate the combined use of cryopreserved human umbilical cord (cUC) allograft and negative pressure wound therapy (NPWT) in treating complex diabetic foot ulcers (DFUs) with bone exposure and osteomyelitis. These types of wound are known to carry a high morbidity and mortality.

METHODS

A single-center, retrospective chart review was performed to assess the efficacy of the combined use of cUC with NPWT, by the same surgeon, to help promote the closure of complex DFUs presenting with biopsy-proven osteomyelitis. Change in wound size and volume, time to wound closure, and number of cUC applications were assessed.

RESULTS

We identified of 14 wounds in 13 patients, with an average initial wound area of (mean±standard devaition) 33.2±21.7cm² and wound volume of 52±26.2cm³. All achieved complete re-epithelialisation with an average time to closure of 24.0±10.9 weeks, using between 2-5 cUC applications. No adverse events were noted and none of the wounds required limb amputation during the a follow-up of 24 months for each patient.

CONCLUSION

The results suggest that combined use of cUC and NPWT may be effective in improving the healing of complex DFUs that present with osteomyelitis. Prospective, randomised controlled trials are warranted to confirm this efficacy as well as its potential applications in other chronic wounds.

Concise Review: Fetal Membranes in Regenerative Medicine: New Tricks from an Old Dog?

The clinical application of the fetal membranes dates back to nearly a century. Their use has ranged from superficial skin dressings to surgical wound closure. The applications of the fetal membranes are constantly evolving, and key to this is the uncovering of multiple populations of stem and stem-like cells, each with unique properties that can be exploited for regenerative medicine. In addition to pro-angiogenic and immunomodulatory properties of the stem and stem-like cells arising from the fetal membranes, the dehydrated and/or decellularized forms of the fetal membranes have been used to support the growth and function of other cells and tissues, including adipose-derived mesenchymal stem cells. This concise review explores the biological origin of the fetal membranes, a history of their use in medicine, and recent developments in the use of fetal membranes and their derived stem and stem-like cells in regenerative medicine. Stem Cells Translational Medicine 2017;6:1767-1776.

Bronchopulmonary dysplasia: Pathophysiology and potential anti-inflammatory therapies

Inflammation of the preterm lungs is key to the pathogenesis of bronchopulmonary dysplasia (BPD), whether it arises as a consequence of intrauterine inflammation or postnatal respiratory management. This review explores steroidal and non-steroidal therapies for reducing neonatal pulmonary inflammation, aimed at treating or preventing BPD.

In Vitro Effect of Estradiol and Progesterone on Ovine Amniotic Epithelial Cells

Amniotic epithelial cells (AECs), an emerging source of extrafoetal stem cells, have recently attracted attention for their great regenerative potential. Since AEC amplifications are accompanied by the loss of their native epithelial phenotype and by the progressive reduction of relevant biological properties, the issue to be addressed is the development of effective culture protocols. In this context, recently, it has been demonstrated that progesterone (P₄) supplementation during ovine AEC (oAEC) expansion could prevent the undesirable epithelial-mesenchymal transition (EMT). In contrast, there is no information to date on the role of the other pregnancy steroids in culture. With this aim, the present study has been designed to clarify the impact of estradiol (E₂), alone or in combination with P₄ (12.5 μM and 25 μM), during oAEC amplification. Steroid supplementations were assessed by testing oAEC proliferation, stemness, EMT, and osteogenic or chondrogenic plasticity. The results indicated that EMT can be prevented exclusively in the presence of high doses of P₄, while it occurred rapidly in cells exposed to E₂ as denoted by protein (cytokeratin-8 and alpha-SMA) and gene expression (vimentin and snail) profiles. Moreover, steroid exposure was able to influence highly oAEC plasticity. Particularly, P₄-treated cells displayed a precommitment towards osteogenic lineage, confirmed by the upregulation of OCN, RUNX2, and the greater deposition of calcium nodules. Conversely, P₄ exposure inhibited oAEC chondrogenic differentiation, which was induced in E₂-treated cells as confirmed by the upregulation of chondrogenesis-related genes (SOX9, ACAN, and COL2A1) and by the accumulation of Alcian blue-positive extracellular matrix. Simultaneously, E₂-treated cells remained unresponsive to osteogenic inductive stimuli. In conclusion, media supplementation with high doses of steroids may be adopted to modulate phenotype and plasticity during oAEC amplification. Relevantly, the osteo or chondro steroid-induced precommitment may open unprecedented cell-based therapies to face the unsolved orthopaedic issues related to osteochondral regeneration.

Human amnion cells for the prevention of bronchopulmonary dysplasia: a protocol for a phase I dose escalation study

INTRODUCTION

Bronchopulmonary dysplasia (BPD), an important sequela of preterm birth, is associated with long-term abnormalities of lung function and adverse neurodevelopmental outcomes. Inflammation, inhibition of secondary septation and vascular maldevelopment play key roles in the pathogenesis of BPD. Human amnion epithelial cells (hAECs), stem-like cells, derived from placental tissues are able to modulate the inflammatory milieu and, in preclinical studies of BPD-like injury, restore lung architecture and function. Allogeneic hAECs may present a new preventative and reparative therapy for BPD.

METHODS AND ANALYSIS

In this two centre, phase I cell dose escalation study we will evaluate the safety of intravenous hAEC infusions in preterm infants at high risk of severe BPD. Twenty-four infants born at less than 29 weeks' gestation will each receive intravenous hAECs beginning day 14 of life. We will escalate the dose of cells contained in a single intravenous hAEC infusion in increments from 2 million cells/kg to 10 million cells/kg. Further dose escalation will be achieved with repeat infusions given at 5 day intervals to a maximum total dose of 30 million cells/kg (three infusions). Safety is the primary outcome. Infants will be followed-up until 2 years corrected age. Additional outcome measures include a description of infants' cytokine profile following hAEC infusion, respiratory outcomes including BPD and pulmonary hypertension and other neonatal morbidities including neurodevelopmental assessment at 2 years.

ETHICS AND DISSEMINATION

This study was approved on the June12th, 2018 by the Human Research Ethics Committee of Monash Health and Monash University. Recruitment commenced in August 2018 and is expected to take 18 months. Accordingly, follow-up will be completed mid-2022. The findings of this study will be disseminated via peer-reviewed journals and at conferences.

PROTOCOL VERSION

5, 21 May 2018.

TRIAL REGISTRATION NUMBER

ACTRN12618000920291; Pre-results.

Human neonatal stem cell-derived skin substitute improves healing of severe burn wounds in a rat model

Conventional approaches can repair minor skin injuries; however, severe burn injuries require innovative approaches for efficient and better wound repair. Recent studies indicate that stem cell-based regenerative therapies can restore severe damaged skin both structurally and functionally. The current study aims to evaluate the wound healing potential of skin substitute derived from human neonatal stem cells (hNSCs) using a severe burn injury rat model. Amniotic epithelial cells (AECs) and mesenchymal stem cells (MSCs) were isolated from placenta (a source of neonatal stem cells) by explant culture method. After characterization, AECs and umbilical cord-MSCs were differentiated into keratinocyte and fibroblasts, respectively. Morphological changes, and expression of corresponding keratinocyte and fibroblast specific markers were used to verify differentiation into respective lineage. A skin substitute was developed by mixing hNSCs-derived skin cells (hNSCs-SCs) in plasma for transplantation in a rat model of severe burn injury. Results indicated that placenta-derived AECs and MSCs were efficiently differentiated into skin cells, that is, keratinocytes and fibroblasts, respectively, as indicated by morphological changes, immunostaining, and polymerase chain reaction analysis. Further, transplantation of hNSCs-SCs seeded in plasma significantly improved basic skin architecture, re-epithelization rate, and wound healing concurrent with reduced apoptosis. In conclusion, neonatal stem cell-derived skin substitute efficiently improved severe burn wounds in a rat model of burn injury. Unique properties of placenta-derived stem cells make them superlative candidates for the development of "off-the-shelf" artificial skin substitutes for future use.

Prospective study of cryopreserved placental tissue wound matrix in the management of chronic venous leg ulcers

OBJECTIVE

Chronic venous leg ulcers (VLUs) affect up to 2% of the general population, resulting in a significant socioeconomic burden. Placental tissue that contains mesenchymal stem cells and active growth factors has been shown to be beneficial in healing of chronic wounds. We compared the efficacy of a human viable wound matrix (hVWM) of cryopreserved placental tissue for the treatment of refractory VLUs with standard therapy.

METHODS

This prospective single-center open-label single-arm study enrolled patients with Clinical, Etiology, Anatomy, and Pathophysiology clinical class C6 VLUs. The ulcers of all enrolled patients had failed to heal after a trial of standard therapy of at least 12 weeks, which included weekly multilayer compression therapy along with local wound care. The same patients subsequently received application of hVWM (Grafix; Osiris Therapeutics, Columbia, Md) every 1 to 2 weeks in addition to standard therapy. Healing with hVWM therapy was then compared with standard therapy, with each patient serving as his own control.

RESULTS

There were 30 VLUs in 21 consecutive eligible patients who were enrolled in the study. All patients were men with an average age of 67 years (standard deviation [SD], ±10.8 years), and the average area of venous ulcers before hVWM initiation was 12.2 cm² (SD, ±14.6 cm²; range, 3.3-12.3 cm²). Duplex ultrasound confirmed superficial or deep system venous reflux in all patients. Complete ulcer healing was achieved in 53% (16/30) of VLUs refractory to standard therapy after application of hVWM. There was a mean reduction in wound surface area by 79% (SD, ±27.3%; P < .001 compared with standard therapy) after a mean treatment time of 10.9 weeks. Eighty percent of VLUs were reduced in size by half compared with 25% with standard therapy (P < .001). The mean rate of reduction in ulcer area after hVWM applications was 1.69% per day vs 0.73% per day with standard therapy (P = .01).

CONCLUSIONS

Cryopreserved placental tissue (hVWM) improves healing processes to achieve complete wound closure in a significant proportion of chronic VLUs refractory to standard therapy. Adjunctive therapy with hVWM provides superior healing rates in refractory VLUs.

On the Cutting Edge: Wound Care for the Endovascular Specialist

Clinical outcomes in patients with critical limb ischemia (CLI) depend not only on endovascular restoration of macrovascular blood flow but also on aggressive periprocedural wound care. Education about this area of CLI therapy is essential not only to maximize the benefits of endovascular therapy but also to facilitate participation in the multidisciplinary care crucial to attaining limb salvage. In this article, we review the advances in wound care products and therapies that have granted the wound care specialist the ability to heal previously nonhealing wounds. We provide a primer on the basic science behind wound healing and the pathogenesis of ischemic wounds, familiarize the reader with methods of tissue viability assessment, and provide an overview of wound debridement techniques, dressings, hyperbaric therapy, and tissue offloading devices. Lastly, we explore emerging technology on the horizons of wound care.

Advancements in Regenerative Strategies Through the Continuum of Burn Care

Burns are caused by several mechanisms including flame, scald, chemical, electrical, and ionizing and non-ionizing radiation. Approximately half a million burn cases are registered annually, of which 40 thousand patients are hospitalized and receive definitive treatment. Burn care is very resource intensive as the treatment regimens and length of hospitalization are substantial. Burn wounds are classified based on depth as superficial (first degree), partial-thickness (second degree), or full-thickness (third degree), which determines the treatment necessary for successful healing. The goal of burn wound care is to fully restore the barrier function of the tissue as quickly as possible while minimizing infection, scarring, and contracture. The aim of this review is to highlight how tissue engineering and regenerative medicine strategies are being used to address the unique challenges of burn wound healing and define the current gaps in care for both partial- and full-thickness burn injuries. This review will present the current standard of care (SOC) and provide information on various treatment options that have been tested pre-clinically or are currently in clinical trials. Due to the complexity of burn wound healing compared to other skin injuries, burn specific treatment regimens must be developed. Recently, tissue engineering and regenerative medicine strategies have been developed to improve skin regeneration that can restore normal skin physiology and limit adverse outcomes, such as infection, delayed re-epithelialization, and scarring. Our emphasis will be centered on how current clinical and pre-clinical research of pharmacological agents, biomaterials, and cellular-based therapies can be applied throughout the continuum of burn care by targeting the stages of wound healing: hemostasis, inflammation, cell proliferation, and matrix remodeling.

Human Amniotic Membrane: A Versatile Scaffold for Tissue Engineering

The human amniotic membrane (hAM) is a collagen-based extracellular matrix derived from the human placenta. It is a readily available, inexpensive, and naturally biocompatible material. Over the past decade, the development of tissue engineering and regenerative medicine, along with new decellularization protocols, has recast this simple biomaterial as a tunable matrix for cellularized tissue engineered constructs. Thanks to its biocompatibility, decellularized hAM is now commonly used in a broad range of medical fields. New preparation techniques and composite scaffold strategies have also emerged as ways to tune the properties of this scaffold. The current state of understanding about the hAM as a biomaterial is summarized in this review. We examine the processing techniques available for the hAM, addressing their effect on the mechanical properties, biodegradation, and cellular response of processed scaffolds. The latest in vitro applications, in vivo studies, clinical trials, and commercially available products based on the hAM are reported, organized by medical field. We also look at the possible alterations to the hAM to tune its properties, either through composite materials incorporating decellularized hAM, chemical cross-linking, or innovative layering and tissue preparation strategies. Overall, this review compiles the current literature about the myriad capabilities of the human amniotic membrane, providing a much-needed update on this biomaterial.

Bioactivity and composition of a preserved connective tissue matrix derived from human placental tissue

There are a wide variety of extracellular matrices that can be used for regenerative purposes. Placental tissue-based matrices are quickly becoming an attractive option given the availability of the tissue source and the wide variety of bioactive molecules knows to exist in unprocessed placental tissues. As fresh placental tissues are seldom an option at the point of care, we examined both the composition and bioactivity of a commercially packaged flowable placental connective tissue matrix (FPTM) (BioECM^® , Skye Biologics, Inc.) that was preserved by the proprietary HydraTek^® process. The FPTM contained significant amounts of collagen and various growth factors such as bFGF, EGF, PDGF, KGF, and PIGF. In addition, it contained high levels of tissue inhibitors of metalloproteinases (TIMP-1 and 2) and molecules known to modulate the immune response including TGF-β and IL-4. In terms of its bioactivity, the FPTM displayed the ability (1) to suppress INF-γ secretion in activated T-cells nearly fourfold over control media, (2) to inhibit methicillin resistant Staphylococcus aureus (MRSA) and Staphylococcus saprophyticus proliferation, (3) to increase the migration of adipose-derived stem cells (ASCs) nearly threefold over control media and (4) to adhere to ASCs in culture. When ASCs were exposed to FPTM in culture, the cells maintained healthy morphology and showed no significant changes in the expression of five genes involved in tissue growth and repair as compared to culture in standard growth media. © 2018 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2731-2740, 2018.