Dehydrated human amnion/chorion membrane regulates stem cell activity in vitro

Human amniotic membrane modulates collagen production and deposition in vitro

Pathological fibrosis is a significant complication of surgical procedures resulting from the accumulation of excess collagen at the site of repair which can compromise the tissue architecture and severely impede the function of the affected tissue. Few prophylactic treatments exist to counteract this process; however, the use of amniotic membrane allografts has demonstrated promising clinical outcomes. This study aimed to identify the underlying mechanism of action by utilizing relevant models that accurately represent the pathophysiology of the disease state. This study employed a pro-fibrotic in vitro system using TGFβ1 stimulation and macromolecular crowding techniques to evaluate the mechanism by which amniotic membrane allografts regulate collagen biosynthesis and deposition. Following treatment with dehydrated human amnion chorion membrane (DHACM), subsequent RNA sequencing and functional enrichment with Reactome pathway analysis indicated that amniotic membranes are indeed capable of regulating genes associated with the composition and function of the extracellular matrix. Furthermore, macromolecular crowding was used in vitro to expand the evaluation to include both the effects of DHACM and a lyophilized human amnion/chorion membrane (LHACM). DHACM and LHACM regulate the TGFβ pathway and myofibroblast differentiation. Additionally, both DHACM and LHACM modulate the production, secretion, and deposition of collagen type I, a primary target for pathological fibrosis. These observations support the hypothesis that amniotic membranes may interrupt pathological fibrosis by regulating collagen biosynthesis and associated pathways.

PURION® processed human amnion chorion membrane allografts retain material and biological properties supportive of soft tissue repair

The reparative properties of amniotic membrane allografts are well-suited for a broad spectrum of specialties. Further enhancement of their utility can be achieved by designing to the needs of each application through the development of novel processing techniques and tissue configurations. As such, this study evaluated the material characteristics and biological properties of two PURION® processed amniotic membrane products, a lyophilized human amnion, intermediate layer, and chorion membrane (LHACM) and a dehydrated human amnion, chorion membrane (DHACM). LHACM is thicker; therefore, its handling properties are ideal for deep, soft tissue deficits; whereas DHACM is more similar to a film-like overlay and may be used for shallow defects or surgical on-lays. Characterization of the similarities and differences between LHACM and DHACM was conducted through a series of in vitro and in vivo studies relevant to the healing cascade. Compositional analysis was performed through histological staining along with assessment of barrier membrane properties through equilibrium dialysis. In vitro cellular response was assessed in fibroblasts and endothelial cells using cell proliferation, migration, and metabolic assays. The in vivo cellular response was assessed in an athymic nude mouse subcutaneous implantation model. The results indicated the PURION® process preserved the native membrane structure, nonviable cells and collagen distributed in the individual layers of both products. Although, LHACM is thicker than DHACM, a similar composition of growth factors, cytokines, chemokines and proteases is retained and consequently elicit comparable in vitro and in vivo cellular responses. In culture, both treatments behaved as potent mitogens, chemoattractants and stimulants, which translated to the promotion of cellular infiltration, neocollagen deposition and angiogenesis in a murine model. PURION® processed LHACM and DHACM differ in physical properties but possess similar in vitro and in vivo activities highlighting the impact of processing method on the versatility of clinical use of amniotic membrane allografts.

Dehydrated human amnion/chorion membrane to treat venous leg ulcers: a cost-effectiveness analysis

OBJECTIVE

To evaluate the cost-effectiveness of dehydrated human amnion/chorion membrane (DHACM) in Medicare enrolees who developed a venous leg ulcer (VLU).

METHOD

This economic evaluation used a four-state Markov model to simulate the disease progression of VLUs for patients receiving advanced treatment (AT) with DHACM or no advanced treatment (NAT) over a three-year time horizon from a US Medicare perspective. DHACM treatments were assessed when following parameters for use (FPFU), whereby applications were initiated 30-45 days after the initial VLU diagnosis claim, and reapplications occurred on a weekly to biweekly basis until completion of the treatment episode. The cohort was modelled on the claims of 530,220 Medicare enrolees who developed a VLU between 2015-2019. Direct medical costs, quality-adjusted life years (QALYs), and the net monetary benefit (NMB) at a willingness-to-pay threshold of $100,000/QALY were applied. Univariate and probabilistic sensitivity analyses (PSA) were performed to test the uncertainty of model results.

RESULTS

DHACM applied FPFU dominated NAT, yielding a lower per-patient cost of $170 and an increase of 0.010 QALYs over three years. The resulting NMB was $1178 per patient in favour of DHACM FPFU over the same time horizon. The rate of VLU recurrence had a notable impact on model uncertainty. In the PSA, DHACM FPFU was cost-effective in 63.01% of simulations at the $100,000/QALY threshold.

CONCLUSION

In this analysis, DHACM FPFU was the dominant strategy compared to NAT, as it was cost-saving and generated a greater number of QALYs over three years from the US Medicare perspective. A companion VLU Medicare outcomes analysis revealed that patients who received AT with a cellular, acellular and matrix-like product (CAMP) compared to patients who received NAT had the best outcomes. Given the added clinical benefits to patients at lower cost, providers should recommend DHACM FPFU to patients with VLU who qualify. Decision-makers for public insurers (e.g., Medicare and Medicaid) and commercial payers should establish preferential formulary placement for reimbursement of DHACM to reduce budget impact and improve the long-term health of their patient populations dealing with these chronic wounds.

DECLARATION OF INTEREST

Support for this analysis was provided by MiMedx Group, Inc., US. JLD, and RAF are employees of MiMedx Group, Inc. WHT, BH, PS, BGC and WVP were consultants to MiMedx Group, Inc. VD, AO, MRK, JAN, NW and GAM served on the MiMedx Group, Inc. Advisory Board. MRK and JAN served on a speaker's bureau. WVP declares personal fees and equity holdings from Stage Analytics, US.

Dehydrated human amnion/chorion membrane allograft with spongy layer to significantly improve the outcome of chronic non-healing wounds

We investigated the healing effect of a new dehydrated amnion/chorion membrane with a spongy layer over a 30-month period in 32 patients with 53 chronic non-healing wounds of different aetiologies. Wounds with <40% surface reduction after 4 weeks of best wound treatment underwent weekly allograft application by a certified wound specialist based on national guidelines and a standardised protocol until complete healing or definite treatment interruption. The main outcome measure was the percentage of wound surface reduction from baseline calculated using digital planimetry follow-up photographs. Overall, 38 (71.7%) wounds presented a favourable outcome (70%-100% area reduction), with 35 (66%) completely healing over a median time of 77 days (range 29-350 days). Favourable outcomes were observed in 75% of traumatic wounds, surgical wounds, venous leg ulcers and pressure injuries, as well as in 50% of ischaemic wounds. Wounds being present <12 months were significantly more likely to have a favourable outcome than more long-standing wounds (χ2  = 7.799; p = 0.005; OR = 3.378; 95% CI, 1.410-8.092). Thus, treatment with dehydrated amnion/chorion membrane with a spongy layer improves the outcome of non-healing wounds of different aetiologies and, therefore, has to be considered early in the management of refractory wounds.

Treatment patterns and outcomes of Medicare enrolees who developed venous leg ulcers

OBJECTIVE

To retrospectively evaluate the comorbidities, treatment patterns and outcomes of Medicare enrolees who developed venous leg ulcers (VLUs).

METHOD

Medicare Limited Data Standard Analytic Hospital Inpatient and Outpatient Department Files were used to follow patients who received medical care for a VLU between 1 October 2015 and 2 October 2019. Patients diagnosed with chronic venous insufficiency (CVI) and a VLU were propensity matched into four groups based on their treatment regimen. Episode claims were used to document demographics, comorbidities and treatments of Medicare enrolees who developed VLUs, as well as important outcomes, such as time to ulcer closure, rates of complications and hospital utilisation rates. Outcomes were compared across key propensity-matched groups.

RESULTS

In total, 42% of Medicare enrolees with CVI (n=1,225,278), developed at least one VLU during the study, and 79% had their episode claim completed within one year. However, 59% of patients developed another VLU during the study period. This analysis shows that only 38.4% of VLU episodes received documented VLU conservative care treatment. Propensity-matched episodes that received an advanced treatment or high-cost skin substitutes for a wound which had not progressed by 30 days demonstrated the best outcomes when their cellular, acellular, matrix-like product (CAMP) treatment was applied weekly or biweekly (following parameters for use). Complications such as rates of infection (33%) and emergency department visits (>50%) decreased among patients who received an advanced treatment (following parameters for use).

CONCLUSION

Medicare enrolees with CVI have diverse comorbidities and many do not receive sufficient management, which contributes to high rates of VLUs and subsequent complications. Medicare patients at risk of a VLU who receive early identification and advanced CAMP treatment demonstrated improved quality of life and significantly reduced healthcare resource utilisation.

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 split-mouth randomised controlled trial comparing the clinical effects of MVISTA with chorion membrane or connective tissue graft in multiple gingival recessions

Objectives

Modified form of VISTA (MVISTA), a novel surgical procedure, aims at comprehensive root coverage that maintains the inner continuity of the periosteum and papilla. This technique incorporates any regenerative graft material within the tunnel. The objective of study is to compare the MVISTA for treating multiple adjacent gingival recessions and chorion membranes or grafts of connective tissues.

Materials and methods

This is a split-mouth type randomized trial. In this trial total of 18 patients were considered. The patients in this trial had multiple adjacent, gingival recessions of Miller's Classes I/II, and they were randomized to either the MVISTA with chorion membrane (test) or connective tissue graft (CTG) (control) group. A baseline and one year after surgery were considered for recording to mean root coverage (MRC), complete root coverage (CRC), and clinical periodontal parameters. An intragroup comparison was made.

Results

The intragroup comparison of recession depth baseline and 12 months after-surgery record found a significant difference between the two groups (P = 0.00). In the postoperative condition, the depth of recession reduction was higher in the test group than in the control group. However, from a statistical perspective, the difference was insignificant (P > 0.05). At the end of the year, it was found that the width of the keratinized tissue had increased significantly (P < 0.05). The MRC in the test group was significantly higher (91.33 %±8.17 %) than that in the control group (89.46 %±11.22 %) (P > 000). At the end of 1 year, the test group showed 66.67 % CRC compared to 44.44 % in the control group. The gingival phenotype displayed statistically significant improvement in the test group (p = 0.004). PD and CAL showed statistically nonsignificant outcomes (P > 0.05).

Conclusions

As far as multiple adjacent gingival recession treatment is concerned, MVISTA with chorion membrane treatment enhanced the gingival phenotype, restored complete root coverage (66.6%), and increased the width of keratinized tissue. CTG and CM demonstrated good root coverage results; the latter might be used as a substitute graft to treat multiple recessions.

A composite of hepatocyte growth factor and 5α-dihydrotestosterone-gelatin microspheres with adipose-derived stem cells enhances wound healing

INTRODUCTION

Reconstructing sebaceous glands is one goal of functionally healing patients who have suffered severe burns, instead of the simple pursuit of wound closure. Effective regeneration of skin appendages remains a challenge in skin wound management and research.

OBJECTIVE

The aim of this study was to evaluate the differentiation of ADSC into sebaceous glands, and clarified the involvement of HGF and 5α-DHT in this process.

METHODS

This study used hepatocyte growth factor (HGF)- and 5α-dihydrotestosterone (5α-DHT)-gelatin microspheres to treat human adipose-derived stem cells (ADSCs) and investigated the reconstruction of sebaceous glands. HGF- and 5α-DHT-gelatin microspheres were constructed using microcapsule slow-release technology. Mice full-thickness skin-wound model was established to evaluate wound healing and hematoxylin-eosin staining was utilized to determine the skin structure.

RESULTS

In vitro analyses found that HGF- and 5α-DHT-gelatin microspheres promoted migration of and tube formation by ADSCs. Furthermore, AKT/ERK signaling, which is related to sebocyte and sweat gland epithelial cell growth, were activated after HGF and 5α-DHT treatment. An in vivo wound healing model demonstrated that ADSCs primed with amnion-loaded HGF- and 5α-DHT-gelatin microspheres promoted wound healing and increased sebaceous gland formation compared to the control group.

CONCLUSIONS

This study confirms the efficacy of ADSCs treated with amnion and HGF- and 5α-DHT-gelatin microspheres in accelerating wound healing and effectively restoring sebaceous glands. This engineered tissue provides insight into and a novel therapeutic material for burns and full-thickness skin wounds.¬¬.

Foot Wounds and the Reconstructive Ladder

Background:

Foot soft tissue coverage represents a challenge to reconstructive surgeons due to a lack of donor sites for this specialized skin. This glabrous tethered thick skin is designed to withstand weight bearing stress and is hard to replace. The limited arch of rotation of foot local flaps contributes to further difficulties. In this study, we share our experience in foot soft tissue loss coverage using techniques tailored to each wound presentation.

Methods:

This case series presents eight patients with wounds of the plantar and dorsal surfaces of the foot, heel, and ankle. Closure techniques were selected and planned based on wound presentation and comorbidity status.

Results:

Patients’ mean age at surgery was 61 years. Etiologies of wounds include trauma, frostbite, diabetic ulceration, malignancy, pressure ulcer with osteomyelitis, and necrotizing infection. Coverage techniques included split and full-thickness skin graft, medial plantar arch pinch graft, cultured epithelial autograft, Hyalomatrix wound device, EpiFix tissue matrix, pedicle flap, and free rectus flap. Complete soft tissue coverage was achieved in each case within reasonable postoperative periods, and ambulation was preserved and/or restored.

Conclusions:

Foot soft tissue reconstruction is challenging and should be planned carefully due to the required specialized skin replacement. Primary closure should be considered first and attempted if possible. Technique escalation in accordance with the reconstructive ladder should be undertaken based on wound etiology, presentation, amount and nature of tissue loss, available resources, and surgeon experience.

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.

Dehydrated human amniotic membrane regulates tenocyte expression and angiogenesis in vitro: Implications for a therapeutic treatment of tendinopathy

Tendon injuries are among the most common ailments of the musculoskeletal system. Prolonged inflammation and persistent vasculature are common complications associated with poor healing. Damaged tendon, replaced with scar tissue, never completely regains the native structural or biomechanical properties. This study evaluated the effects of micronized dehydrated human amnion/chorion membrane (μdHACM) on the inflammatory environment and hypervascularity associated with tendinopathy. Stimulation of human tenocytes with interleukin‐1 beta (IL1β) induced the expression of inflammatory and catabolic markers, resulting in secretion of active MMPs and type 3 collagen that is associated with a degenerative phenotype. Treatment with μdHACM diminished the effects of IL1β, reducing the expression of inflammatory genes, proteases, and extracellular matrix components, and decreasing the presence of active MMP and type 3 collagen. Additionally, a co‐culture model was developed to evaluate the effects of μdHACM on angiogenesis associated with tendinopathy. Micronized dHACM differentially regulated angiogenesis depending upon the cellular environment in which it was placed. This phenomenon can be explained in part through the detection of both angiogenic protagonists and antagonists in μdHACM. Observations from this study identify a mechanism by which μdHACM regulates inflammatory processes and angiogenesis in vitro, two key pathways implicated in tendinopathic injuries.

Dehydrated human amniotic membrane modulates canonical Wnt signaling in multiple cell types in vitro

Canonical Wnt signaling is a major pathway known to regulate diverse physiological processes in multicellular organisms. Signaling is tightly regulated by feedback mechanisms; however, persistent dysregulation of this pathway is implicated in the progression of multiple disease states. In this study, proteomic analysis identified endogenous Wnt antagonists in micronized dehydrated human amnion/chorion membrane (μdHACM); thereby, prompting a study to further characterize the intrinsic properties of μdHACM as it relates to Wnt activity, in vitro. A TCF/LEF reporter cell line demonstrated the general ability of μdHACM to inhibit β-catenin induced transcription activity. Furthermore, in vitro systems, modeling elevated Wnt signaling, were developed in relevant cell types including tenocytes, synoviocytes, and human dermal fibroblasts (HDFs). Stimulation of these cells with Wnt3A resulted in translocation of β-catenin to the nucleus and increased expression of Wnt related genes. The subsequent addition of μdHACM, in the continued presence of Wnt-stimulus, mitigated the downstream effects of Wnt3A in tenocytes, synoviocytes, and HDFs. Nuclear localization of β-catenin was abated with corresponding reduction of Wnt related gene expression. These data demonstrate the in vitro regulation of canonical Wnt signaling as an inherent property of μdHACM and a novel mechanism of action.

Dehydrated Human Amniotic Membrane Inhibits Myofibroblast Contraction through the Regulation of the TGFβ‒SMAD Pathway In Vitro

Excessive fibrosis affects more than 100 million patients yearly, leading to the accumulation of extracellular matrix that compromises tissue architecture and impedes its function. Intrinsic properties of the amniotic membrane have alluded to its potential to inhibit excessive fibrosis; therefore, this study aimed to investigate the effects of dehydrated human amnion/chorion membrane (dHACM) on dermal fibroblasts and their role in fibrotic pathways. Human dermal fibroblasts were stimulated with TGFβ1, triggering myofibroblast-like characteristics in vitro. Subsequent addition of dHACM in the continued presence of TGFβ1 inhibited downstream signaling, leading to a reduction in the expression of known fibrotic and extracellular matrix genes. In addition, dHACM decreased alpha-smooth muscle actin, a stress filament responsible for contractile activity in scarring. The functional outcome of these effects was observed in an ex vivo model for cellular contraction. Hyperactivation of TGFβ signaling increased the contractile capacity of myofibroblasts embedded within a collagen substrate. Simultaneous addition of dHACM treatment prevented the marked contraction, which is likely a direct result of the inhibition of TGFβ signaling mentioned earlier. These observations may support the use of dHACM in the regulation of fibroblast activity as it relates to tissue fibrosis.

Comprehensive Comparison of Amnion Stromal Cells and Chorion Stromal Cells by RNA-Seq

Mesenchymal stromal cells derived from the fetal placenta, composed of an amnion membrane, chorion membrane, and umbilical cord, have emerged as promising sources for regenerative medicine. Here, we used next-generation sequencing technology to comprehensively compare amniotic stromal cells (ASCs) with chorionic stromal cells (CSCs) at the molecular and signaling levels. Principal component analysis showed a clear dichotomy of gene expression profiles between ASCs and CSCs. Unsupervised hierarchical clustering confirmed that the biological repeats of ASCs and CSCs were able to respectively group together. Supervised analysis identified differentially expressed genes, such as LMO3, HOXA11, and HOXA13, and differentially expressed isoforms, such as CXCL6 and HGF. Gene Ontology (GO) analysis showed that the GO terms of the extracellular matrix, angiogenesis, and cell adhesion were significantly enriched in CSCs. We further explored the factors associated with inflammation and angiogenesis using a multiplex assay. In comparison with ASCs, CSCs secreted higher levels of angiogenic factors, including angiogenin, VEGFA, HGF, and bFGF. The results of a tube formation assay proved that CSCs exhibited a strong angiogenic function. However, ASCs secreted two-fold more of an anti-inflammatory factor, TSG-6, than CSCs. In conclusion, our study demonstrated the differential gene expression patterns between ASCs and CSCs. CSCs have superior angiogenic potential, whereas ASCs exhibit increased anti-inflammatory properties.

Insights on the Human Amniotic Membrane in Clinical Practice with a Focus on the New Applications in Retinal Surgery

Recently, the use of the human amniotic membrane (hAM) has been extended to treat retinal disorders such as refractory macular holes, retinal breaks and dry and wet age-related macular degeneration. Not only the hAM has proved to be an excellent tool for repairing retinal tissue, but it has also shown a promising regeneration potential. This review aims to highlight the novel use of the hAM in treating retinal diseases. Although the hAM has been used in the ocular anterior segment reconstruction for more than 60 years, in the last 2 years, we have found in literature articles showing the use of the hAM in the retinal surgery field with interesting results in terms of tissue healing and photoreceptor regeneration.

Dehydrated Human Amnion Chorion Membrane as Treatment for Pediatric Burns

Objective: Pediatric burns are a major source of injury and in the absence of adequate care can lead to lifelong functional loss and disfigurement. While split thickness skin autografts are the current standard of care for deep partial and full-thickness burns, this approach is associated with considerable morbidity. For this reason, alternative skin substitutes such as allografts have gained interest. Approach: In the present study, we present a case series of 30 children with various types of burns treated with dehydrated human amnion chorion membrane (dHACM). Results: We show that treatment with dHACM is associated with an excellent rate of healing comparable to split thickness skin grafts with less rate of hypertrophic scar and contracture. Innovation: Treatment with dHACM is particularly attractive as it consists of many tissue regenerative factors, such as growth factors and immune modulators, thus it will reduce the risk of scaring. Conclusion: While dHACM is associated with an increased upfront cost, treating patients with small to moderate-sized burns with dHACM in their regional centers works to decrease downstream costs such as management of prolonged pain from donor-site morbidity, revisional surgeries from scar and contractures of split thickness grafts, and avoiding the cost of transfer to higher level centers of care. Our findings challenge the current standard of care, suggesting that dHACM provides an alternative to the current use of split thickness skin grafting and is a safe, feasible, and potentially superior substitute for the management of small to moderate total body surface area partial and full-thickness pediatric burns.

A novel chemotactic factor derived from the extracellular matrix protein decorin recruits mesenchymal stromal cells in vitro and in vivo

Soft tissue is composed of cells surrounded by an extracellular matrix that is made up of a diverse array of intricately organized proteins. These distinct components work in concert to maintain homeostasis and respond to tissue damage. During tissue repair, extracellular matrix proteins and their degradation products are known to influence physiological processes such as angiogenesis and inflammation. In this study we developed a discovery platform using a decellularized extracellular matrix biomaterial to identify new chemotrophic factors derived from the extracellular matrix. An in vitro culture of RAW.264 macrophage cells with the biomaterial ovine forestomach matrix led to the identification of a novel ~12 kDa chemotactic factor, termed ‘MayDay’, derived from the N-terminal 31–188 sequence of decorin. The recombinant MayDay protein was shown to be a chemotactic agent for mesenchymal stromal cells in vitro and in vivo. We hypothesize that the macrophage-induced cleavage of decorin, via MMP-12, leads to the release of the chemotactic molecule MayDay, that in turn recruits cells to the site of damaged tissue.

Perinatal tissues and cells in tissue engineering and regenerative medicine

Perinatal tissues are an abundant source of human extracellular matrix proteins, growth factors and stem cells with proved potential use in a wide range of therapeutic applications. Due to their placental origin, these tissues possess unique biological properties, including being angiogenic, anti-inflammatory, anti-fibrotic, anti-microbial and immune privileged. Additionally, as a temporary organ, placenta is usually discarded as a medical waste, thus providing an easily available, cost effective, 'unlimited' and ethical source of raw materials. Although some of these tissues, such as the amniotic membrane and umbilical cord, have been used in clinical practices, most of them continue to be highly under explored. This review aims to outline the most relevant applications of perinatal tissues as a source of biomaterials and stem cells in the exciting fields of tissue engineering and regenerative medicine (TERM), as well as highlight how these solutions can be used to overcome the shortage of adequate scaffolds and cell sources that currently hampers the translation of TERM strategies towards clinical settings. STATEMENT OF SIGNIFICANCE: Stem cells and extracellular matrix derived from perinatal tissues such as placenta and umbilical cord, have drawn great attention for use in a wide variety of applications in the biomedical field. Due to their origin, these tissues possess unique biological properties, including being angiogenic, anti-inflammatory, anti-fibrotic, anti-microbial and immune privileged. Also they are typically considered medical waste, thus providing an easily available, cost effective, 'unlimited' and ethical source of raw materials. This work aims to present and discuss the most relevant applications of perinatal tissues as a source of biomaterials and stem cells in the exciting fields of tissue engineering and regenerative medicine (TERM).

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.

Estimating the economic value of emerging technologies in chronic wound therapy

Estimating the economic value of emerging technologies in clinical medicine presents a number of problems. New technologies may have a limited clinical history, few supportive peer‐reviewed publications, and only anecdotal evidence as they enter the market and seek clinician approval and reimbursement from payers. Although clinical efficacy/effectiveness research is a minimal starting point for making the case for adoption of a product, establishing a competitive cost‐effectiveness position against other products and establishing the case for economic value must be made as well when presenting to health plans or other payers. Economic valuation methods have been well developed in the business community. Reviewed here are the components of a well‐crafted case for the economic value of a product in general and in the wound industry specifically, in a multidomain approach to demonstrate values using demographic, clinical, financial, operational, and intangible assessments.

Effect of Preparation Method on the Protein Profile of Equine Amnion Dressings

The protein content of amnion is thought to be the primary contributor to its efficacy as a biological dressing for wounds. Protein elution into antibiotic processing media has been reported, but the effect of antiseptic-based processing methods is unknown. Amniotic membranes were collected from eight healthy mares. Samples were collected after removal of gross debris. Tissues were subsequently divided and processed with either 0.05% chlorhexidine or 2% iodine/0.25% acetic acid. After protein extraction and trypsin digestion, the proteins were labeled with 8-plex iTRAQ tags, combined, and analyzed by high-resolution liquid chromatography-mass spectrometry. The MaxQuant-Perseus software suite was used to identify and quantify sample proteins, with functional annotation performed in PANTHER. There were 220 unique proteins identified, of which 144 were found in all individuals and across all conditions, several with a known role in wound healing. Contrary to expectations, processing did not significantly alter the protein content of the amnion tissue. Limitations include the small sample size and single time point. These results suggest that either processing method is acceptable for use in the preparation of equine amnion dressings. The role of expressed proteins in the biological activity of amnion dressings remains to be elucidated.

Evaluation of dehydrated human umbilical cord biological properties for wound care and soft tissue healing

Chronic wounds are a significant health care problem with serious implications for quality of life because they do not properly heal and often require therapeutic intervention. Amniotic membrane allografts have been successfully used as a biologic therapy to promote soft tissue healing; however, the umbilical cord, another placental-derived tissue, has also recently garnered interest because of its unique composition but similar placental tissue origin. The aim of this study was to characterize PURION® PLUS Processed dehydrated human umbilical cord (dHUC) and evaluate the biological properties of this tissue that contribute to healing. This was performed through the characterization of the tissue composition, evaluation of in vitro cellular response to dHUC treatment, and in vivo bioresorption and tissue response in a rat model. It was observed that dHUC contains collagen I, hyaluronic acid, laminin, and fibronectin. Additionally, 461 proteins that consist of growth factors and cytokines, inflammatory modulators, chemokines, proteases and inhibitors, adhesion molecules, signaling receptors, membrane-bound proteins, and other soluble regulators were detected. Cell-based assays demonstrated an increase in adipose-derived stem cell and mesenchymal stem cell proliferation, fibroblast migration and endothelial progenitor cell vessel formation in a dose-dependent manner after dHUC treatment. Lastly, rat subcutaneous implantation demonstrated biocompatibility since dHUC allografts were resorbed without fibrous encapsulation. These findings establish that dHUC possesses biological properties that stimulate cellular responses important for soft tissue healing. © 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 107B: 1035-1046, 2019.

Biochemical characterization of pure dehydrated binate amniotic membrane: role of cytokines in the spotlight

AIM

Placental allografts used for tissue regeneration differ in membrane compositions and processing techniques. A uniquely folded dehydrated binate amniotic membrane (DBAM) was biochemically characterized to evaluate its potential role in wound healing.

METHODS

Histology, Luminex-based immunoassay and standard in vitro cell biology techniques were employed.

RESULTS

Histological staining confirmed that the DBAM was chorion free with epithelial cell layer of the respective amnion membranes facing outward. DBAM had quantifiable levels of relevant cytokines that induced proliferation and migration while bolstering secretory activity of the cells. DBAM retained biological efficacy at a broad range of temperatures.

CONCLUSION

Cytokines in DBAM stimulate bone marrow stromal and stem cells that may lead to tissue regeneration and wound healing in a clinical setup.

Healing Effects of Dried and Acellular Human Amniotic Membrane and Mepitelas for Coverage of Skin Graft Donor Areas; A Randomized Clinical Trial

Objective

To compare the healing effects of dried and acellular human amniotic membrane and Mepitel for coverage of split-thickness graft donor site (STGDS).

Methods

Twenty patients who underwent STGDS regeneration surgery in identical anatomic regions were enrolled in this randomized controlled clinical trial conducted in Hazrate Fatemeh hospital (Iran). Patients were randomly assigned in 3 groups of wound dressing; group A by Mepitel, group B AmiCare (Dried amniotic membrane) and group C OcuReg-A (Acellular amniotic membrane). Re-epithelization rate (healing time), pain sensation, scar formation and infection rate were assessed till complete healing was achieved.

Results

Our results showed no significant difference between Amicare, OcuReg-A and Mepitel in the features analyzed by us including: Re-epithelization rate (healing time) P value; 0.573, Pain sensation P value: day 4 th: 0.131, day8 th: 0.93 and day 12 th: 0.365, Scar formation P value>0.05and Infection rate.

Conclusion

Our findings confirmed the safety and efficacy of AmiCare (dried amniotic membrane) and OcuReg-A (Acellular amniotic membrane) in treatment of split-thickness donor site in comparison with Mepitel as a standard wound dressing. Trial registration number: IRCT201511118177N12.

Experience in Using Fetal Membranes: The Present and New Perspectives

INTRODUCTION

The placenta is an accessible source of tissues for transplantation. Placental transplants have been used in wound treatment because of the basic function of the placenta and its nutritious properties and structure.

PATIENTS AND METHODS

The aim of this work is to present the clinical usage of fetal membranes, including human amnion, on the basis of the burn treatment center's experience. The clinical use of amnion and different types of placental transplants are described. The initial results of research work within the MEDPIG project are presented regarding the application of placenta from transgenic pigs as a source of tissues for transplantation.

RESULTS

From August 2011 to March 2017, 252,592 cm² of biostatic human amnion transplants were prepared in our tissue bank. During this period they were transplanted to 528 patients, including 10 patients with Lyell syndrome. Initial studies were conducted in which placentas were collected from 5 transgenic pigs and 27,426 cm² of amniotic grafts were prepared from them.

DISCUSSION

The authors' own experience as well as the literature confirm the extraordinary efficiency of transplants prepared from placental tissues, especially from the amniotic membrane.

CONCLUSIONS

The clinical effects confirm the effectiveness of using human amnion in wound treatment. Amniotic transplant is a new treatment standard in toxic epidermal necrolysis TEN (Lyell's syndrome), which has found confirmation in very good clinical outcomes. The collected placentas from transgenic animals enabled the preparation of significantly more grafts than in the case of human material, which is a great advantage of this source of placenta over human tissues.

Current Techniques for Burn Reconstruction: Using Dehydrated Human Amnion/Chorion Membrane Allografts as an Adjunctive Treatment Along the Reconstructive Ladder

The reconstructive ladder is a term coined by reconstructive plastic surgeons to describe levels of increasingly complex management of wounds. The first rungs of the ladder is allowing the wound to heal by secondary intention, advancing up the ladder to direct tissue closure, with skin grafting and tissue transfer (flaps) comprising the higher rungs. Skin grafting and tissue transfer (flaps) at the middle and higher rungs of the ladder are often necessary for the treatment of complex burn injuries. Our purpose is to describe how dehydrated human amnion/chorion membrane allografts may be used as an adjunctive treatment.

Amnion Membrane in Diabetic Foot Wounds: A Meta-analysis

Background:

Amniotic membrane is tissue obtained from human placenta rich in cytokines, growth factors, and stem cells that possess the ability to inhibit infection, improve healing, and stimulate regeneration.

Methods:

A meta-analysis was performed examining randomized controlled trials comparing amniotic tissue products with standard of care in nonhealing diabetic foot ulcers including PubMed, Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Reviews.

Results:

A search of 3 databases identified 596 potentially relevant articles. Application of selection criteria led to the selection of 5 randomized controlled trials. The 5 selected randomized controlled trials represented a total of 311 patients. The pooled relative risk of healing with amniotic products compared with control was 2.7496 (2.05725–3.66524, P < 0.001).

Conclusions:

The current meta-analysis indicates that the treatment of diabetic foot ulcers with amniotic membrane improves healing rates in diabetic foot ulcers. Further studies are needed to determine whether these products also decrease the incidence of subsequent complications, such as amputation or death, in diabetic patients.

Identification of Extracellular Matrix Components and Biological Factors in Micronized Dehydrated Human Amnion/Chorion Membrane

Objective: The use of bioactive extracellular matrix (ECM) grafts such as amniotic membranes is an attractive treatment option for enhancing wound repair. In this study, the concentrations, activity, and distribution of matrix components, growth factors, proteases, and inhibitors were evaluated in PURION^® Processed, micronized, dehydrated human amnion/chorion membrane (dHACM; MiMedx Group, Inc.).

Approach: ECM components in dHACM tissue were assessed by using immunohistochemical staining, and growth factors, cytokines, proteases, and inhibitors were quantified by using single and multiplex ELISAs. The activities of proteases that were native to the tissue were determined via gelatin zymography and EnzChek^® activity assay.

Results: dHACM tissue contained the ECM components collagens I and IV, hyaluronic acid, heparin sulfate proteoglycans, fibronectin, and laminin. In addition, numerous growth factors, cytokines, chemokines, proteases, and protease inhibitors that are known to play a role in the wound-healing process were quantified in dHACM. Though matrix metalloproteinases (MMPs) were present in dHACM tissues, inhibitors of MMPs overwhelmingly outnumbered the MMP enzymes by an overall molar ratio of 28:1. Protease activity assays revealed that the MMPs in the tissue existed primarily either in their latent form or complexed with inhibitors.

Innovation: This is the first study to characterize components that function in wound healing, including inhibitor and protease content and activity, in micronized dHACM.

Conclusion: A variety of matrix components and growth factors, as well as proteases and their inhibitors, were identified in micronized dHACM, providing a better understanding of how micronized dHACM tissue can be used to effectively promote wound repair.

Human amniotic membrane grafts in therapy of chronic non-healing wounds

BACKGROUND

Human amniotic membrane (HAM) has been embraced as a natural wound dressing almost exclusively in ophthalmology. Only recently, emergence of commercial HAM products prompted its use in growing range of indications, especially treatment of chronic non-healing wounds.

SOURCES OF DATA

ClinicalTrials.gov database and International Clinical Trials Registry Platform searched with key words 'human amniotic membrane' and 'chronic wounds'.

AREAS OF AGREEMENT

HAM can be successfully used as a natural wound dressing to promote healing.

AREAS OF CONTROVERSY

It is still unclear, which preparation is more advantageous, cryopreserved HAM or dehydrated HAM.

GROWING POINTS

There are an increasing number of commercial HAM products and clinical trials for a variety of dermatological diagnoses.

AREAS TIMELY FOR DEVELOPING RESEARCH

In spite of easy procurement and low production costs, to our knowledge, there are currently only a few manufacturers of commercial HAM products tested in clinical trials for cutaneous wounds and all of them are located in the USA.

Type I and II Diabetic Adipose-Derived Stem Cells Respond In Vitro to Dehydrated Human Amnion/Chorion Membrane Allograft Treatment by Increasing Proliferation, Migration, and Altering Cytokine Secretion

Objective: Human amniotic membranes have been shown to be effective for healing diabetic foot ulcers clinically and to regulate stem cell activity in vitro and in vivo; however, diabetic stem cells may be impaired as a sequela of the disease. In this study, dehydrated human amnion/chorion membrane (dHACM) allografts (EpiFix^®; MiMedx Group) were evaluated for their ability to regulate diabetic stem cells in vitro. Approach: Human adipose-derived stem cells (ADSCs) from normal, type I diabetic, and type II diabetic donors were treated with soluble extracts of dHACM and evaluated for proliferation after 3 days by DNA assay, chemotactic migration after 1 day by transwell assay, cytokine secretion after 3 days by multiplex ELISA, and gene expression after 5 days by reverse transcription-polymerase chain reaction. Results: Although diabetic ADSCs demonstrated decreased responses compared to normal ADSCs, dHACM treatment stimulated diabetic ADSCs to proliferate after 3 days and enhanced migration over 24 h, similar to normal ADSCs. dHACM-treated diabetic ADSCs modulated secretion of soluble signals, including regulators of inflammation, angiogenesis, and healing. All ADSCs evaluated also responded to dHACM treatment with altered expression of immunomodulatory genes, including interleukins (IL)-1α, IL-1β, and IL-1RA. Innovation: This is the first reported case demonstrating that diabetic ADSCs respond to novel amniotic membrane therapies, specifically treatment with dHACM. Conclusion: dHACM stimulated diabetic ADSCs to migrate, proliferate, and alter cytokine expression suggesting that, despite their diabetic origin, ADSCs may respond to dHACM to accelerate diabetic wound healing.

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

Background and Objectives

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

Methods

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

Results

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

Conclusion

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

Dehydrated human amnion/chorion membrane regulates stem cell activity in vitro

Human‐derived placental tissues have been shown in randomized clinical trials to be effective for healing chronic wounds, and have also demonstrated the ability to recruit stem cells to the wound site in vitro and in vivo. In this study, PURION^® Processed dehydrated human amnion/chorion membrane allografts (dHACM, EpiFix^®, MiMedx Group, Marietta, GA) were evaluated for their ability to alter stem cell activity in vitro. Human bone marrow mesenchymal stem cells (BM‐MSCs), adipose derived stem cells (ADSCs), and hematopoietic stem cells (HSCs) were treated with soluble extracts of dHACM tissue, and were evaluated for cellular proliferation, migration, and cytokine secretion. Stem cells were analyzed for cell number by DNA assay after 24 h, closure of an acellular zone using microscopy over 3 days, and soluble cytokine production in the medium of treated stem cells was analyzed after 3 days using a multiplex ELISA array. Treatment with soluble extracts of dHACM tissue stimulated BM‐MSCs, ADSCs, and HSCs to proliferate with a significant increase in cell number after 24 h. dHACM treatment accelerated closure of an acellular zone by ADSCs and BM‐MSCs after 3 days, compared to basal medium. BM‐MSCs, ADSCs, and HSCs also modulated endogenous production of a number of various soluble signals, including regulators of inflammation, mitogenesis, and wound healing. dHACM treatment promoted increased proliferation and migration of ADSCs, BM‐MSCs, and HSCs, along with modulation of secreted proteins from those cells. Therefore, dHACM may impact wound healing by amplifying host stem cell populations and modulating their responses in treated wound tissues. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1495–1503, 2016.