Skin substitutes as treatment for chronic wounds: current and future directions

Comparing Amniotic Membranes to Other Bioengineered Skin Substitutes in Wound Healing: A Propensity Score-Matched Analysis

Background/Objectives: The amniotic membrane, which is widely available and inexpensive, has received recent attention for its potential applications in wound healing. This is the first study to use a large database to examine the efficacy of amniotic membrane grafting compared to other skin substitutes. Methods: The TriNetX electronic health database was queried in October 2024 for patients with burns or chronic skin ulcers. Patients were stratified by treatment with amniotic membrane grafts or another skin substitute. These patients were then 1:1 propensity score-matched based on age, demographics, and comorbidities. Group differences were assessed with risk ratios and p-values. Results: A total of 557 patients remained in each group after propensity score matching. Patients who were treated with amniotic membrane grafts had significantly decreased hypertrophic scarring (1.7% vs. 6.2%, p < 0.0001), local skin infections (17.4% vs. 29.9%, p < 0.0001), and acute postoperative pain (3.7% vs. 7.8%, p = 0.003). Additionally, subsequent split-thickness skin grafting was utilized significantly less after amniotic membrane grafts. When compared to skin substitutes for large wounds (>100 cm2), the advantages of amniotic membrane were even more pronounced. Conclusions: This multi-institutional study supports amniotic membranes as a viable alternative to conventional bioengineered skin substitutes. Further research should evaluate amniotic membranes in wound beds of different sizes to better characterize their use in preparation for or as an alternative to skin grafting itself.

Programmed wound healing in aged skin may be enhanced by mesenchymal cell loaded gene-activated scaffolds

Aging can prolong the wound healing and is associated with decline in stem cells, delays in cellular migration, and lower vascularization. Tissue engineering has largely evolved to incorporate advanced three-dimensional wound dressings, scaffolds, and hydrogels that may be seeded with mesenchymal stromal cells (MSCs) to foster an environment conducive to regeneration and enhance the healing process. The effectiveness of stem cell-seeded scaffolds can be improved by incorporating activating agents such as nucleic acids resulting in gene-activated scaffolds (GAS), thereby facilitating targeted wound healing in aged patients. In this study, we assess the in vivo wound healing potential of a promising MSC seeded gene-activated collagen scaffold, containing the anti-fibrotic agent β-klotho and pro-angiogenic stromal derived factor (SDF-1α) in aged male Sprague Dawley rats (20-24 month old). A MSC cell loaded split skin model compared MSC only with the clinical standard dressing +Jelonet, MSCs +gene-free collagen scaffold, and MSCs +SDF-1α/β-klotho dual gene-activated collagen scaffold up to 21 days. Our results showed wound healing in all groups except in MSC +Jelonet which showed scab formation with exudate. MSC only group healed primarily via fibrotic contraction. In contrast, the scaffold groups showed host tissue integration and a redistribution of extracellular matrix proteins, less contraction, and complete re-epithelized wounds at day 21. The dual GAS displayed programmed wound healing with the greatest neo-vascularization CD31 expression. In conclusion, wound healing in aged rats can be effectively modulated when MSCs are loaded on biocompatible collagen scaffolds, particularly when these scaffolds are loaded with anti-fibrotic and pro-angiogenic factors. This approach enhances blood vessel formation while reducing fibrosis, suggesting a promising potential for programmed wound healing strategies in aged chronic wounds.

Comparing Flaps and Artificial Dermis for Skull Base Osteoradionecrosis Repair in Nasopharyngeal Carcinoma

OBJECTIVE

This study compares the effectiveness of pedicled flaps, free flaps, and artificial dermis in reconstructing skull base osteoradionecrosis (sbORN) in nasopharyngeal carcinoma (NPC) patients and evaluates their impact on long-term survival.

METHODS

A retrospective analysis of 210 NPC patients with sbORN who underwent endoscopic debridement and reconstruction between April 2018 and October 2024 was conducted. Patients were categorized into pedicled flap (104 cases), free flap (43 cases), and artificial dermis (63 cases) groups. Surgical success rates, complications, and survival outcomes were analyzed using statistical methods, including Kaplan-Meier, Cox regression analyses, t-tests, chi-square tests, and non-parametric rank-sum test.

RESULTS

The pedicled flap group had the highest surgical success rate (75%) compared to free flaps (53.5%) and artificial dermis (30.2%) (p < 0.001). No significant differences were found in overall complications or ICU admission rates (p > 0.05), though no pedicled flap patients required ICU care. Survival analysis showed a significantly lower mortality risk in the pedicled flap group than in the artificial dermis group (HR = 0.400, p = 0.019), while the free flap group had no significant difference (p > 0.05).

CONCLUSION

Pedicled flaps demonstrated superior surgical success and long-term survival benefits, suggesting they should be the preferred option for sbORN reconstruction. Future research should refine surgical techniques and explore novel reconstructive materials to optimize outcomes.

LEVEL OF EVIDENCE: 3

Progress in the application of ablative fractional lasers in chronic wounds

This literature review aims to explore the application of ablative fractional laser in chronic wound healing, focusing on its clinical efficacy and mechanisms of action. Additionally, it summarizes the various lasers and parameters utilized by the authors in their studies. A comprehensive literature search was conducted for studies published between 2008 and 2025 in the Google Scholar, Web of Science, Medline, and PubMed databases, using the keywords: Fractional, Laser, Chronic Wounds, Ulcers, Healing. A substantial body of evidence suggests that carbon dioxide (CO₂) and erbium: yttrium aluminum garnet (Er: YAG) lasers can significantly accelerate the healing of chronic wounds. However, treatment protocols vary considerably across studies, particularly in terms of treatment frequency, power output, and energy density. This lack of standardization makes it challenging to compare outcomes directly and to determine optimal treatment parameters. The majority of studies conclude that CO₂ and Er: YAG laser therapies effectively promote the repair of chronic wounds. Proposed mechanisms include precise debridement, reduction of bacterial burden, improved local perfusion, enhanced transdermal drug delivery, and activation of key signaling pathways, such as Transforming growth factor-β/smad(TGF-β/Smad). Further research is needed to establish standardized treatment protocols and identify the most effective laser parameters for clinical use.

Optimizing Wound Healing in Radial Forearm Donor Sites: A Comparative Study of Ulnar-Based Flap and Split-Thickness Skin Grafting

Background: The radial forearm free flap (RFFF) is a common technique in head and neck reconstructive surgery. This study aimed to compare the clinical and biochemical outcomes of wound healing following ulnar-based transposition flap (UBTF) versus split-thickness skin grafting (STSG) for donor site closure, with a particular emphasis on tissue regeneration. Materials and Methods: A total of 24 patients (6 women, 18 men), underwent RFFF reconstruction. The donor site was closed using the UBTF technique in 10 cases, while STSG was performed in 14 cases. Postoperative complications-including necrosis, edema, hematoma, infection, and wound dehiscence-along with healing times were assessed daily during the first seven postoperative days and at monthly follow-ups over six months. Pre- and postoperative biochemical analyses included hemoglobin (HB), white blood cell count (WBC), platelets (PLT), albumin, and C-reactive protein (CRP) levels. An aesthetic evaluation of the flap was also performed. Results: The two groups were homogeneous. Postoperative complications occurred more frequently in the STSG group, which also demonstrated significantly longer healing times (p = 0.0004). In contrast, the UBTF group showed significantly better aesthetic outcomes in terms of skin color (p = 0.000021), skin texture (p = 0.000018), and flap stability (p = 0.0398). Additionally, pre- and postoperative PLT counts were significantly higher in the UBTF group (p = 0.001 and p = 0.043, respectively). Conclusions: While STSG remains a well-established method for forearm donor site closure following RFFF harvest, this study demonstrates that UBTF is a viable alternative associated with better clinical and aesthetic outcomes.

Hydrogel-based dressing for wound healing: A systematic review of clinical trials

BACKGROUND

Chronic wounds pose significant healthcare challenges. Hydrogel-based wound dressings have garnered significant attention in the field of wound care. Furthermore, no severe adverse effect was reported for treatment with hydrogel in wound healing. However, a comprehensive review of their clinical application for enhancing chronic wound healing is lacking.

OBJECTIVES

This systematic review evaluates their clinical effectiveness of hydrogel-based dressing in managing chronic wounds and assesses the evidence supporting their use.

SEARCH METHODS

We searched the following databases PubMed, the Cochrane Library; Web of Science; and ClinicalTrials.gov. from January 2010 to January 2023.

SELECTION CRITERIA

Published clinical trial studies that evaluate the effect of hydrogel-based dressing on chronic wounds.

RESULT

We included 39 studies with 1786 participants (1818 wounds), 1024 of whom (1100 wounds) received hydrogel dressings while 679 patients (725 wounds) used non-hydrogel dressings. This systematic review of clinical research indicates that utilizing hydrogel dressings could potentially reduce the required time (31.17 ± 21.74 days) for wound healing and enhance the percentage of wound closure (63.76 ± 28.97 %).

CONCLUSIONS

This systematic review revealed that hydrogel dressings are effective in treatment of chronic wounds. Nonetheless, there is a necessity for additional long-term trials tailored to specific wound types and patient characteristics.

A Multicenter, Randomized, Controlled, Clinical Trial Evaluating a Lyopreserved Amniotic Membrane in the Treatment of Venous Leg Ulcers

Background

Standard of Care (SoC) with multilayer compression therapy along with proper wound management, may not be sufficient to close all venous ulcers and needs advanced therapies.

Methods

In this multicenter, prospective, randomized, controlled, open-label trial, 351 patients were screened, 200 were eligible and enrolled and were randomized 1:1 to LPM (lyopreserved cellular placental membrane) plus SoC or SoC alone for up to 12 weeks. Patients were enrolled between June 2018 and November 2020 at 30 sites across the United States. Outcome measures included complete closure of the index ulcer (primary), reduction in wound size, rate of closure, quality of life, and adverse events.

Results

ITT analysis revealed that wounds treated with weekly applications of LPM as an adjunct to standard of care, reduced in size significantly more than SoC alone, at the end of 4, 8, and 12 graft applications, indicating a faster progression to closure. There was a statistically 1.72 higher relative risk or 72% higher probability of wound closure with LPM compared to the SoC group during the study period for wounds with an initial size of 3-25 cm2. Use of LPM as an adjunct was able to close statistically larger-sized wounds on average. There was also a statistically significant fivefold improvement in quality of life (overall physical symptoms and daily life) over baseline, in the LPM treated patients as compared to the control group.

Conclusion

LPM and standard of care, significantly closed more venous leg ulcers and faster than standard of care alone and improved the quality of life for patients, suggesting that the use of aseptically processed LPM is a safe and effective treatment option in the healing of chronic venous leg ulcers. Trial Registration: ClinicalTrials.gov ID: NCT03629236, Study to Evaluate Safety and Efficacy of GrafixPL for the Treatment of Venous Leg Ulcers. (https://clinicaltrials.gov/study/NCT03629236).

Exploring the Efficacy of Selected Allografts in Chronic Wound Healing: Evidence from Murine Models and Clinical Data for a Proposed Treatment Algorithm

Significance: Chronic wounds can lead to poor outcomes for patients, with risks, including amputation and death. In the United States, chronic wounds affect 2.5% of the population and cost up to $28 billion per year in primary health care costs. Recent Advances: Allograft tissues (dermal, amnion, and amnion/chorion) have shown efficacy in improving healing of chronic, recalcitrant wounds in human patients, as evidenced by multiple clinical trials. Their mechanisms of actions have been relatively understudied, until recently. Research in murine models has shown that dermal allografts promote reepithelialization, amnion allografts promote granulation tissue formation and angiogenesis, and amnion/chorion allografts support all stages of wound healing. These findings confirm their effectiveness and illuminate their therapeutic mechanisms. Critical Issues: Despite the promise of allografts in chronic wound care, a gap exists in understanding which allografts are most effective during each wound healing stage. The variable efficacy among each type of allograft suggests a mechanistic approach toward a proposed clinical treatment algorithm, based on wound characteristics and patient's needs, may be beneficial. Future Directions: Recent advances in allografts provide a framework for further investigations into patient-specific allograft selection. This requires additional research to identify which allografts support the best outcomes during each stage of wound healing and in which wound types. Longitudinal human studies investigating the long-term impacts of allografts, particularly in the remodeling phase, are also essential to developing a deeper understanding of their role in sustained wound repair and recovery.

Production and Characterization of Plant Extract-Based Cell-Friendly and High Mechanical Strength Nanofiber Wound Dressings by Electrospinning Technique

This study focused on the development of wound dressings. Plant active ingredients such as clover, chickweed, chamomile, garlic, liverwort, bitter melon, pine resin, marigold (Calendula officinalis), and St. John's Wort (Hypericum perforatum L.) were reinforced with polyethylene oxide (PEO) and polyvinyl alcohol (PVA) polymers, and nanofiber membranes were produced by electrospinning. As a result of the analyses, FTIR confirmed the presence of polymer and active ingredient functional groups in the composite membranes; softening and shifting were observed in the peaks. In the FEGSEM analysis, a thin and regular nanofiber structure was obtained in the S12 membrane in the range of 150-500 nm. In the tensile test, the tensile strength of the S12 sample was measured as 25.89 MPa, and this strength was associated with the homogeneous distribution and thinning of the fibers. In the mesenchymal stem cell analysis, cell viability was determined as 98%, and cell death was determined as 2% for the S12 membrane at the end of 72 h. The results show that the S12 composite membrane can be used as a biomaterial with ideal properties in wound healing applications.

Advances in Designer Materials for Chronic Wound Healing

Significance: Nonhealing or chronic wounds represent a significant and growing global health concern, imposing substantial burdens on individuals, health care systems, and economies worldwide. Although the standard-of-care treatment involves the application of wound dressings, most dressing materials are not specifically designed to address the pathological processes underlying chronic wounds. This review highlights recent advances in biomaterial design tailored to chronic wound healing. Recent Advances: Chronic wounds are characterized by persistent inflammation, impaired granulation tissue formation, and delayed re-epithelialization. Newly developed designer materials aim to manage reactive oxygen species and extracellular matrix degradation to suppress inflammation while promoting vascularization, cell proliferation, and epithelial migration to accelerate tissue repair. Critical Issues: Designing optimal materials for chronic wounds remains challenging due to the diverse etiology and a multitude of pathological mechanisms underlying chronic wound healing. While designer materials can target specific aberrations, designing a materials approach that restores all aberrant wound-healing processes remains the Holy Grail. Addressing these issues requires a deep understanding of how cells interact with the materials and the complex etiology of chronic wounds. Future Directions: New material approaches that target wound mechanics and senescence to improve chronic wound closure are under development. Layered materials combining the best properties of the approaches discussed in this review will pave the way for designer materials optimized for chronic wound healing.

First-in-kind 3D bioprinted human skin model using recombinant human collagen

Reliable translational human skin models are lacking for modeling skin diseases and screening effective therapeutics. 3D bioprinting is an emerging technology that enables the fabrication of human skin models that mimic the structure and functions of human skin in a dish (in-vitro). As a prototype, we present a first-in-kind fully humanized 3D bioprinted skin model as an alternative to animal testing for preclinical research. This model utilizes a plant-derived recombinant human collagen and human skin fibroblasts, melanocytes, and keratinocytes. The 3D bioprinted human skin model expresses involucrin and cytokeratin 14, contains melanin granules, and structurally resembles human skin. However, the morphology of keratinocytes is slightly different, containing a thicker layer of proliferative keratinocytes and a thinner layer of differentiated, cornified keratinocytes. Nevertheless, the model shows epidermal stratification, which indicates skin maturation. Further, the model lacks skin appendages such as hair follicles and sweat glands, as current bioprinting technology cannot deliver distinct cells at the single-cell resolution. Recent advances in 3D bioprinting such as spheroid-based bioprinting show potential to address these limitations. Hence, 3D bioprinting of skin using plant-derived recombinant human collagen, presents significant advantages, including high-throughput production of personalized human skin models, reduction of animal testing, and potential applications in regenerative medicine.

Counting the Cost of Cellular and/or Tissue-Based Products in Diabetic Foot Ulcers: Is There a Justifiable Price Limit per Square Centimeter?

Objective: To identify how cellular and/or tissue-based products (CTPs) relate to value in terms of cost per quality-adjusted life years (QALYs) in wound care in comparison with treatments in other medical fields. Approach: This is a cross-sectional study and a cost-effectiveness analysis. Payment limits for each CTP were obtained via the Healthcare Common Procedure Coding System Q codes and formulated as cost inputs into a cost-utility model published for treatment of Wagner 1 diabetic foot ulcers using dehydrated human amnion and chorion allograft versus standard of care (SOC). Additional changes to cap the number of CTP applications and adjustments for recent inflation were made. The literature was searched for other cost-utility models in other diabetes-related diseases as a comparison. Results: When the payment limit was ≤$140 per square centimeter, interventions were dominant (less costly, better outcomes) compared with SOC. When the limit exceeded $430 per square centimeter, the cost-effectiveness threshold of $100,000/QALY was exceeded. Newer Q codes are generally much more expensive and likely to not be cost-effective, similar to the results for many other chronic diabetes-related diseases . Innovation: This study presents decision makers with tools, by which they can determine as to whether a given CTP is likely to be cost-effective for patients. Conclusion: Over a third of all CTPs will very likely result in noncost-effective interventions. This number is likely to be higher when wounds are larger or used in other wound types where they are less efficacious. The recent trend in much higher costs for CTPs is worrisome.

A bioactive three-layered skin substitute based on ECM components effectively promotes skin wound healing and regeneration

To overcome the limitations of conventional skin tissue engineering (TE), 3D biofabrication approaches are being developed. However, tissue mimicry should be further improved in skin models. Here, we developed and characterized biomimetic hydrogels to obtain a biofabricated three-layered (BT) skin substitute based on the main components found in the epidermal, dermal, and hypodermal skin layers. Hydrogels for dermal and hypodermal skin layers were based on a mix of agarose and type I collagen, supplemented with skin-related extracellular matrix (ECM) components (dermatan sulfate, hyaluronic acid, and elastin) and loaded with human dermal fibroblasts (hDFs) or human mesenchymal stem/stromal cells (hMSCs), respectively. The epidermal hydrogel was formulated using type I collagen supplemented with keratin and sphingolipids, and seeded with human epidermal keratinocytes (hEKs). Physicochemical results revealed adequate viscosity, gelling times, and pH for each hydrogel solution. The BT Skin also showed good swelling and degradation kinetics, and mechanical properties in a similar range of human skin. The hydrogels and BT Skin demonstrated stable cell viability and metabolic activity, as well as intercellular communication through the release of growth factors. Moreover, the BT Skin demonstrated controlled inflammation in vivo, and produced results comparable to autografting in a mouse skin wound model. This bioactive and biomimetic three-layered BT Skin has a composition that attempts to mimic the natural ECM of the skin, formulated with the characteristic cells and biomolecules present in each skin layer, and offers promising properties for its clinical application in the treatment of patients with skin injuries.

Application of novel strategies in chronic wound management with focusing on pressure ulcers: new perspective

Invading blood cells, extracellular tissue, and soluble mediators all play important roles in the wound-healing process. There is a substantial global burden of disease and mortality attributable to skin defects that do not heal. About 1% to 2% of the population in industrialized nations suffers from chronic wounds that don't heal, despite healthcare breakthroughs; this condition is very costly, costing about $25 billion each year in the US alone. Amputation, infection (affecting as many as 25% of chronic wounds), sepsis, and dermal replacements are all consequences of conventional therapeutic approaches like growth factor therapy and diabetic foot ulcers account for 85% of lower limb amputations. Despite these obstacles, scientists are constantly looking for new ways to speed healing and close wounds. The unique immunomodulatory capabilities and multipotency of mesenchymal stem cells (MSCs) have made them a potential therapeutic choice in tissue engineering and regenerative medicine. Animal models of wound healing have shown that MSCs can speed up the process by as much as 40% through enhancing angiogenesis, modulating inflammation, and promoting fibroblast migration. Clinical trials provide more evidence of their effectiveness; for instance, one RCT found that, after 12 weeks, patients treated with MSCs had a 72% smaller wound size than those in the control group. This review offers a thorough examination of MSCs by combining the latest research with preclinical evidence. Highlighting their potential to transform treatment paradigms, it delves into their biological properties, how they work during regeneration and healing, and therapeutic usefulness in controlling chronic wounds.

A 3D millifluidic model of a dermal perivascular microenvironment on a chip

The process of angiogenesis plays a pivotal role in skin regeneration, ensuring the provision of nutrients and oxygen to the nascent tissue, thanks to the formation of novel microvascular networks supporting functional tissue regeneration. Unfortunately, most of the current therapeutic approaches for skin regeneration lack vascularization, required to promote effective angiogenesis. Thus, in vitro tridimensional models, complemented with specific biochemical signals, can be a valuable tool to unravel the neovascularization mechanisms and develop novel clinical strategies. In this work, we designed and validated a tridimensional microstructured dynamic model of the dermal perivascular microenvironment on a chip. We carried out the fabrication of an array of microstructures by two-photon laser polymerization, then used as a 3D substrate for co-culture of human dermal fibroblasts and endothelial cells. We included the substrate in a miniaturized optically accessible bioreactor (MOAB) which provides the physiological interstitial flow, upon perfusion in the presence or absence of the pro-angiogenic stimuli VEGF and TGF-β1. We determined the parameters to be applied under dynamic conditions by an in silico model simulating individual 3D microenvironments within the bioreactor's chambers. We computed the fluid velocity and wall shear stress acting on endothelial cells along with the oxygen concentration profile, and we chose the most suitable flow rate for maintaining dermal physiological conditions. Experimental results showed the effectiveness of the developed platform as a 3D dynamic model of angiogenesis. This is the first combined experimental and computational study involving chemically stimulated 3D co-cultures for successfully simulating the physiological dermal perivascular microenvironment.

Advancements in bioengineered and autologous skin grafting techniques for skin reconstruction: a comprehensive review

The reconstruction of complex skin defects challenges clinical practice, with autologous skin grafts (ASGs) as the traditional choice due to their high graft take rate and patient compatibility. However, ASGs have limitations such as donor site morbidity, limited tissue availability, and the necessity for multiple surgeries in severe cases. Bioengineered skin grafts (BSGs) aim to address these drawbacks through advanced tissue engineering and biomaterial science. This study conducts a systematic review to describe the benefits and shortcomings of BSGs and ASGs across wound healing efficacy, tissue integration, immunogenicity, and functional outcomes focusing on wound re-epithelialization, graft survival, and overall aesthetic outcomes. Preliminary findings suggest ASGs show superior early results, while BSGs demonstrate comparable long-term outcomes with reduced donor site morbidity. This comparative analysis enhances understanding of bioengineered alternatives in skin reconstruction, potentially redefining best practices based on efficacy, safety, and patient-centric outcomes, highlighting the need for further innovation in bioengineered solutions.

Emerging Technological Advancement for Chronic Wound Treatment and Their Role in Accelerating Wound Healing

Chronic wounds are a major healthcare burden and may severely affect the social, mental, and economic status of the patients. Any impairment in wound healing stages due to underlying factors leads to a prolonged healing time and subsequently to chronic wounds. Traditional approaches for the treatment of chronic wounds include dressing free local therapy, dressing therapy, and tissue engineering based scaffold therapies. However, traditional therapies need improvisation and have been advanced through breakthrough technologies. The present review spans traditional therapies and further gives an extensive account of advancements in the treatment of chronic wounds. Cutting edge technologies, such as 3D printing, which includes inkjet printing, fused deposition modeling, digital light processing, extrusion-based printing, microneedle array-based therapies, gene therapy, which includes microRNAs (miRNAs) therapy, and smart wound dressings for real time monitoring of wound conditions through assessment of pH, temperature, oxygen, moisture, metabolites, and their use for planning of better treatment strategies have been discussed in detail. The review further gives the future direction of treatments that will aid in lowering the healthcare burden caused due to chronic wounds.

Safety evaluation of bi-layered allogenic keratinocyte and fibroblast skin substitute for diabetic foot ulcers-SAFESKIN-DFU: A Phase 1 clinical trial

AIM

To assess the safety and efficacy of a local skin substitute product in the treatment of chronic diabetic foot ulcers (DFUs).

MATERIALS AND METHODS

Five patients were evaluated over 6 months. Skin substitutes were applied twice at 2-week intervals. Patients were monitored for any possible adverse effects and wound improvement.

RESULTS

The results indicated the overall safety of the skin substitute, with only few adverse effects unrelated to this product. Significant reduction in wound size was observed in four patients during the initial 12-week treatment phase, with complete closure in two patients at 24 weeks.

CONCLUSIONS

The application of a bi-layered allogeneic keratinocyte and fibroblast skin substitute in patients with chronic DFU was safe and associated with favourable wound healing results. Adherence to standard treatment protocols, including optimal offloading, is essential to maximize the likelihood of successful wound healing.

From Bank Preparation to Clinical Use of Homologous Skin Allografts in Wound Healing: A Sustainable Approach

Given progressive population ageing and the increase in the number of patients with comorbidities, the management of chronic and/or hard-to-heal wounds (HHWs) nowadays represents a common problem in many clinical settings. In these cases, standard strategies may not be sufficient. Autologous grafting represent the gold standard for permanent wound closure, but is almost never realized when the skin loss is extensive/the patient is young. The grafting of homologous skin/dermal tissue procured from cadaver donors (i.e., allografting) represents the best alternative, especially when the dermal component is lost. This request supports the activities of skin bank establishments (including donor screening, skin procurement, processing, storage, and distribution) that are regulated by specific guidelines and need to continuously meet quality standard requirements. The aim of this work is to both give specific insights of all the procedures implied in allograft preparation as well as an overview of their practical application in the treatment of different HHWs. The particular characteristics of each skin/dermal allograft released by Siena Skin Bank (cryopreserved/glycerol-preserved skin/de-epidermized dermis, acellular lyophilized de-epidermized dermis/reticular dermis) are also discussed. The exemplificative series of HHWs managed in the Dermatology Department of Siena were classified according their etiology into post-traumatic, vascular (arterial/venous/mixed/lymphatic), inflammatory, surgical, and heat/chemical burns. Globally, the clinical advantages obtained include: acceleration of healing process, pain sparing, resistance to bacterial contamination, dermal regeneration (instead of scarring), and better aesthetic-functional outcome.

Liquid-liquid phase transition as a basis for novel materials for skin repair and regeneration

Inorganic materials are of increasing interest not only for bone repair but also for other applications in regenerative medicine. In this study, the combined effects of energy-providing, regeneratively active inorganic polyphosphate (polyP) and also morphogenetically active pearl powder on wound healing were investigated. Aragonite, the mineralic constituent of pearl nacre and thermodynamically unstable form of crystalline calcium carbonate, was found to be converted into a soluble state in the presence of a Ca2+-containing wound exudate, particularly upon addition of sodium polyP (Na-polyP), driven by the transfer of Ca2+ ions from aragonite to polyP, leading to liquid-liquid phase separation to form an aqueous Ca-polyP coacervate. This process is further enhanced in the presence of Ca-polyP nanoparticles (Ca-polyP-NP). Kinetic studies revealed that the coacervation of polyP and nacre aragonite in wound exudate is a very rapid process that results in the formation of a stronger gel with a porous structure compared to polyP alone. Coacervate formation, enabled by phase transition of crystalline aragonite in the presence of Na-polyP/Ca-polyP-NP and wound exudate, could also be demonstrated in a hydroxyethyl cellulose-based hydrogel used for wound treatment. Furthermore, it is shown that Na-polyP/Ca-polyP-NP together with nacre aragonite strongly enhances the proliferation of mesenchymal stem cells and promotes microtube formation in the in vitro angiogenesis assay with HUVEC endothelial cells. The latter effect was confirmed by gene expression studies, applying real-time polymerase chain reaction, using the biomarker genes VEGF (vascular endothelial growth factor) and hypoxia-inducible factor-1 α (HIF-1α). Division of Escherichia coli is suppressed when suspended in a matrix containing Na-polyP/Ca-polyP-NP and aragonite. The potential medical relevance of these findings is supported by an animal study on genetically engineered diabetic mice (db/db), which demonstrated a marked increase in granulation tissue and microvessel formation in regenerating experimental wounds treated with Ca-polyP-NP compared to controls. Co-administration of aragonite significantly accelerated the wound healing-promoting effect of polyP in db/db mice. Based on these results, we propose that the ability of polyP to form a mixed coacervate with aragonite, in addition to its energy (ATP)-generating function, can decisively contribute to the regenerative activity of this polymer in wound repair.

Comparative Effectiveness of Placental Allografts in the Treatment of Diabetic Lower Extremity Ulcers and Venous Leg Ulcers in U.S. Medicare Beneficiaries: A Retrospective Observational Cohort Study Using Real-World Evidence

Objective: To compare the effectiveness of cellular tissue products (CTP) versus standard care in U.S. Medicare beneficiaries with diabetic lower extremity ulcers (DLEUs) or venous leg ulcers (VLUs). Approach: We performed a retrospective cohort study using real-world evidence from U.S. Medicare claims for DLEUs or VLUs between 2016 and 2020. There were three cohorts evaluated: viable cryopreserved placental membrane (vCPM) or viable lyopreserved placental membrane (vLPM); other CTP; and standard care. Claims were collapsed into episodes of care. Univariate and bivariate statistics were used to examine the frequency distribution of demographics and clinical variables. Multivariable zero-inflated binomial regressions were used to evaluate mortality and recurrence trends. Logistic regression compared three adverse outcomes (AOs): amputation; 1-year mortality; and wound recurrence. Results: There were 333,362 DLEU episodes among 261,101 beneficiaries, and 122,012 VLU episodes among 80,415 beneficiaries. DLEU treatment with vLPM was associated with reduced 1-year mortality (-26%), reduced recurrence (-91%), and reduced AOs (-71%). VLU treatment with vCPM or vLPM was associated with reduced 1-year mortality (-23%), reduced recurrence (-80%), and 66.77% reduction in AOs. These allografts were also associated with a 49% and 73% reduced risk of recurrence in DLEU and VLU, respectively, compared with other CTPs. Finally, vCPM or vLPM were associated with noninferior prevention of AOs related to amputation, mortality, and recurrence (95% CI: 0.69-1.14). Conclusions: DLEUs and VLUs treated with vCPM and vLPM allografts are associated with lowered 1-year mortality, wound recurrence, and AOs in DLEUs and VLUs compared with standard care. Decision makers weighing coverage of placental allografts should consider these added short- and long-term clinical benefits relative to costly management and high mortality of Medicare's most frequent wounds.

A Novel Dehydrated Human Umbilical Cord Particulate Medical Device: Matrix Characterization, Performance, and Biocompatibility for the Management of Acute and Chronic Wounds

Chronic wounds present a significant socioeconomic burden forecasted to increase in prevalence and cost. Minimally manipulated human placental tissues have been increasingly employed and proven to be advantageous in the treatment of chronic wounds, showing improved clinical outcomes and cost-effectiveness. However, technological advances have been constrained by minimal manipulation and homologous use criteria. This study focuses on the characterization of a novel dehydrated human umbilical cord particulate (dHUCP) medical device, which offers a unique allogeneic technological advancement and the first human birth tissue device for wound management. Characterization analyses illustrated a complex extracellular matrix composition conserved in the dHUCP device compared to native umbilical cord, with abundant collagens and glycosaminoglycans imbibing an intricate porous scaffold. Dermal fibroblasts readily attached to the intact scaffold of the dHUCP device. Furthermore, the dHUCP device elicited a significant paracrine proliferative response in dermal fibroblasts, in contrast to fibrillar collagen, a prevalent wound device. Biocompatibility testing in a porcine full-thickness wound model showed resorption of the dHUCP device and normal granulation tissue maturation during healing. The dHUCP device is a promising advancement in wound management biomaterials, offering a unique combination of structural complexity adept for challenging wound topographies and a microenvironment supportive of tissue regeneration.

Use of Dermal Substitute Matrices for Coverage of Exposed Limb Vascular Repairs: A Literature Review

Background

Prompt coverage of vascular repairs in the extremities is needed to protect from desiccation and trauma. In the absence of local soft tissues to provide early coverage pending demarcation of the tissues and the zone of injury, there is no clear data in the literature on the ideal coverage method. This article is the first to review the use of dermal substitutes for temporary coverage of extremity vascular repairs pending definitive coverage.

Methods

We conducted a review of the literature to identify previous articles indexed in PubMed and Ovid using these search terms: [(skin) OR (artificial skin) OR (Integra) OR (dermal substitute) OR (dermal substitute matrix) OR (dermal regeneration) OR (dermal regeneration matrix) OR (dermal regeneration template)] AND [(bypass) OR (graft) OR (vascular surgery) OR (revascularization) OR (salvage) OR (limb salvage) OR (vascular repair) OR (artery repair) OR (arterial repair)] AND [(limb) OR (extremity) OR (leg) OR (arm) OR (vascular injury) OR (amputation)].

Results

Of the 32 articles retrieved for initial review, five case reports with six patients of dermal substitute use for direct coverage of extremity repairs were identified. In all cases, the dermal substitute was able to provide stable coverage pending definitive coverage or was allowed to heal secondarily.

Conclusions

Dermal substitute matrices are a potential means of temporary coverage of exposed extremity vascular repairs when there is a paucity of local soft tissues pending more definitive coverage.

Strategic Use of Biodegradable Temporizing Matrix (BTM) in Wound Healing: A Case Series in Asian Patients

Skin and soft tissue reconstruction has long been based on the reconstructive ladder. However, a skin substitute has become popular due to its predictable outcomes, without donor-site morbidity. The biodegradable temporizing matrix (BTM; NovoSorb, PolyNovo Ltd., Port Melbourne, Australia) is a synthetic skin substitute that has recently gained its clinical application. Compared with those of other dermal templates, the clinical efficacy and performance of the BTM are not well established, especially among the Asian population. This study aims to share our experience and strategy of using BTM in various wound conditions. The data of patients who underwent skin and soft tissue reconstruction with BTM at a single institution between January 2022 and December 2023 were reviewed. The patient demographics, wound characteristics, surgical details, secondary procedures, and complications were recorded and analyzed. Postoperative 6-month photographs were collected and independently evaluated by two plastic surgeons and two wound care center nurses using the Manchester Scar Scale (MSS). This study included 37 patients, consisting of 22 males and 15 females with a mean age of 51.8 years (range, 18-86 years old). The wound etiologies included trauma (67.6%), necrotizing soft tissue infection (16.2%), burns (10.8%), toe gangrene (2.7%), and scar excision (2.7%). The average wound area covered by BTM was 50.6 ± 47.6 cm2. Among the patients, eight received concomitant flap surgery and BTM implantation, 20 (54.1%) underwent subsequent split-thickness skin grafts (STSG), and 17 had small wounds (mean: 21.6 cm2) healed by secondary intention. Infection was the most common complication, affecting six patients (n = 6 [16.2%]), five of whom were treated conservatively, and only one required debridement. Thirty-three patients (89.2%) had good BTM take, and only four had BTM failure, requiring further reconstruction. At the last follow-up, 35 out of the 37 patients (94.6%) achieved successful wound closure, and the total MSS score was 10.44 ± 2.94, indicating a satisfactory scar condition. The patients who underwent BTM grafting without STSG had better scar scores than those who received STSG (8.71 ± 2.60 vs. 11.18 ± 2.84, p = 0.039). In conclusion, the BTM is effective and feasible in treating various wounds, with relatively low complication rates, and it can thus be considered as an alternative for skin and soft tissue reconstruction. When combined with adipofasical flap reconstruction, it achieves a more comprehensive anatomical restoration.

Plasticity of bone marrow-derived cell differentiation depending on microenvironments in the skin

Bone marrow-derived cells (BMDCs) are heterogeneous populations in which not only pluripotent stem cells, namely, hematopoietic stem cells (HSCs), mesenchymal stem cells (MSC) but also endothelial progenitor cells (EPC) are involved. BMDCs contribute to the maintenance of homeostasis and recovery from disrupted homeostasis as the immune, endocrine, and nervous systems. The skin is the largest organ in which various tissues, such as the epidermis, dermis, skin appendages (i.e., hair follicles), fats, muscles, and vessels, are tightly and systematically packed. It functions as a physical barrier to block the invasion of harmful substances and pathogenic microorganisms and properly regulate water evaporation. The skin is exposed to injuries from external stimuli because it is the outermost layer and owing to its specificity. Recovery from physical injuries and DNA mutations occurs constantly in the skin, but medical treatments are required for impaired wound healing. Recently, conservative treatments utilizing scaffolds have attracted attention as alternatives to surgical therapy, which is highly invasive. Against this background, numerous scaffolds are available in a clinical setting, although they have not surpassed surgery because of their distinct disadvantages. Here, we discuss the plasticity of BMDCs in the skin to maintain homeostasis, in addition to their critical roles on recovery from disrupted homeostasis. We also share our perspective on how scaffolds can be developed to establish scaffolds beyond surgery to regenerate skin structure during wound healing by maximally utilizing the plasticity of BMDCs.

M.O.I.S.T. Concept for the Local Therapy of Chronic Wounds: An International Update

Chronic wounds remain a significant clinical challenge both for those affected and for healthcare systems. The treatment is often comprised and complex. All patients should receive wound care that is integrated into a holistic approach involving local management that addresses the underlying etiology and provides for gold standard therapy to support healing, avoid complications and be more cost effective. There have been significant advances in medicine over the last few decades. The development of new technologies and therapeutics for the local treatment of wounds is also constantly increasing. To help standardize clinical practice with regard to the multitude of wound products, the M.O.I.S.T. concept was developed by a multidisciplinary expert group. The M stands for moisture balance, O for oxygen balance, I for infection control, S for supporting strategies, and T for tissue management. Since the M.O.I.S.T. concept, which originated in the German-speaking countries, is now intended to provide healthcare professionals with an adapted instrument to be used in clinical practice, and a recent update to the concept has been undertaken by a group of interdisciplinary experts to align it with international standards. The M.O.I.S.T. concept can now be used internationally both as an educational tool and for the practical implementation of modern local treatment concepts for patients with chronic wounds and can also be used in routine clinical practice.

Bioengineering Skin Substitutes for Wound Management-Perspectives and Challenges

Non-healing wounds and skin losses constitute significant challenges for modern medicine and pharmacology. Conventional methods of wound treatment are effective in basic healthcare; however, they are insufficient in managing chronic wound and large skin defects, so novel, alternative methods of therapy are sought. Among the potentially innovative procedures, the use of skin substitutes may be a promising therapeutic method. Skin substitutes are a heterogeneous group of materials that are used to heal and close wounds and temporarily or permanently fulfill the functions of the skin. Classification can be based on the structure or type (biological and synthetic). Simple constructs (class I) have been widely researched over the years, and can be used in burns and ulcers. More complex substitutes (class II and III) are still studied, but these may be utilized in patients with deep skin defects. In addition, 3D bioprinting is a rapidly developing method used to create advanced skin constructs and their appendages. The aforementioned therapies represent an opportunity for treating patients with diabetic foot ulcers or deep skin burns. Despite these significant developments, further clinical trials are needed to allow the use skin substitutes in the personalized treatment of chronic wounds.

Reconstructive Paradigms: A Problem-Solving Approach in Complex Tissue Defects

The field of plastic surgery is continuously evolving, with faster-emerging technologies and therapeutic approaches, leading to the necessity of establishing novel protocols and solving models. Surgical decision-making in reconstructive surgery is significantly impacted by various factors, including the etiopathology of the defect, the need to restore form and function, the patient's characteristics, compliance and expectations, and the surgeon's expertise. A broad surgical armamentarium is currently available, comprising well-established surgical procedures, as well as emerging techniques and technologies. Reconstructive surgery paradigms guide therapeutic strategies in order to reduce morbidity, mortality and risks while maximizing safety, patient satisfaction and properly restoring form and function. The paradigms provide researchers with formulation and solving models for each unique problem, assembling complex entities composed of theoretical, practical, methodological and instrumental elements.

The Use of Photoactive Polymeric Nanoparticles and Nanofibers to Generate a Photodynamic-Mediated Antimicrobial Effect, with a Special Emphasis on Chronic Wounds

This review is concerned with chronic wounds, with an emphasis on biofilm and its complicated management process. The basics of antimicrobial photodynamic therapy (PDT) and its underlying mechanisms for microbial eradication are presented. Intrinsically active nanocarriers (polydopamine NPs, chitosan NPs, and polymeric micelles) that can further potentiate the antimicrobial photodynamic effect are discussed. This review also delves into the role of photoactive electrospun nanofibers, either in their eluting or non-eluting mode of action, in microbial eradication and accelerating the healing of wounds. Synergic strategies to augment the PDT-mediated effect of photoactive nanofibers are reviewed.

Recent Achievements in the Development of Biomaterials Improved with Platelet Concentrates for Soft and Hard Tissue Engineering Applications

Platelet concentrates such as platelet-rich plasma, platelet-rich fibrin or concentrated growth factors are cost-effective autologous preparations containing various growth factors, including platelet-derived growth factor, transforming growth factor β, insulin-like growth factor 1 and vascular endothelial growth factor. For this reason, they are often used in regenerative medicine to treat wounds, nerve damage as well as cartilage and bone defects. Unfortunately, after administration, these preparations release growth factors very quickly, which lose their activity rapidly. As a consequence, this results in the need to repeat the therapy, which is associated with additional pain and discomfort for the patient. Recent research shows that combining platelet concentrates with biomaterials overcomes this problem because growth factors are released in a more sustainable manner. Moreover, this concept fits into the latest trends in tissue engineering, which include biomaterials, bioactive factors and cells. Therefore, this review presents the latest literature reports on the properties of biomaterials enriched with platelet concentrates for applications in skin, nerve, cartilage and bone tissue engineering.

ROS-scavenging materials for skin wound healing: advancements and applications

The intricate healing process of skin wounds includes a variety of cellular and molecular events. Wound healing heavily relies on reactive oxygen species (ROS), which are essential for controlling various processes, including inflammation, cell growth, angiogenesis, granulation, and the formation of extracellular matrix. Nevertheless, an overabundance of reactive oxygen species (ROS) caused by extended oxidative pressure may result in the postponement or failure of wound healing. It is crucial to comprehend the function of reactive oxygen species (ROS) and create biomaterials that efficiently eliminate ROS to enhance the healing process of skin wounds. In this study, a thorough examination is presented on the role of reactive oxygen species (ROS) in the process of wound healing, along with an exploration of the existing knowledge regarding biomaterials employed for ROS elimination. In addition, the article covers different techniques and substances used in the management of skin wound. The future prospects and clinical applications of enhanced biomaterials are also emphasized, highlighting the potential of biomaterials that scavenge active oxygen to promote skin repair. This article seeks to enhance the understanding of the complex processes of ROS in the healing of wounds and the application of ROS-scavenging materials. Its objective is to create novel strategies for effective treatment skin wounds.