Use of a bioartificial dermal regeneration template for skin restoration in combat casualty injuries

Advancements in wound healing: integrating biomolecules, drug delivery carriers, and targeted therapeutics for enhanced tissue repair

Wound healing, a critical biological process vital for tissue restoration, has spurred a global market exceeding $15 billion for wound care products and $12 billion for scar treatment. Chronic wounds lead to delayed or impaired wound healing. Natural bioactive compounds, prized for minimal side effects, stand out as promising candidates for effective wound healing. In response, researchers are turning to nanotechnology, employing the encapsulation of these agents into drug delivery carriers. Drug delivery system will play a crucial role in enabling targeted delivery of therapeutic agents to promote tissue regeneration and address underlying issues such as inflammation, infection, and impaired angiogenesis in chronic wound healing. Drug delivery carriers offer distinct advantages, exhibiting a substantial ratio of surface area to volume and altered physical and chemical properties. These carriers facilitate sustained and controlled release, proving particularly advantageous for the extended process of wound healing, that typically comprise a diverse range of components, integrating both natural and synthetic polymers. Additionally, they often incorporate bioactive molecules. Despite their properties, including poor solubility, rapid degradation, and limited bioavailability, various natural bioactive agents face challenges in clinical applications. With a global research, emphasis on harnessing nanomaterial for wound healing application, this research overview engages advancing drug delivery technologies to augment the effectiveness of tissue regeneration using bioactive molecules. Recent progress in drug delivery has poised to enhance the therapeutic efficacy of natural compounds in wound healing applications.

Analysis of bioprinting strategies for skin diseases and injuries through structural and temporal dynamics: historical perspectives, research hotspots, and emerging trends

This study endeavors to investigate the progression, research focal points, and budding trends in the realm of skin bioprinting over the past decade from a structural and temporal dynamics standpoint. Scholarly articles on skin bioprinting were obtained from WoSCC. A series of bibliometric tools comprising R software, CiteSpace, HistCite, and an alluvial generator were employed to discern historical characteristics, evolution of active topics, and upcoming tendencies in the area of skin bioprinting. Over the past decade, there has been a consistent rise in research interest in skin bioprinting, accompanied by an extensive array of meaningful scientific collaborations. Concurrently, diverse dynamic topics have emerged during various periods, as substantiated by an aggregate of 22 disciplines, 74 keywords, and 187 references demonstrating citation bursts. Four burgeoning research subfields were discerned through keyword clustering-namely, #3 'in situbioprinting', #6 'vascular', #7 'xanthan gum', and #8 'collagen hydrogels'. The keyword alluvial map reveals that Module 1, including 'transplantation' etc, has primarily dominated the research module over the previous decade, maintaining enduring relevance despite annual shifts in keyword focus. Additionally, we mapped out the top six key modules from 2023 being 'silk fibroin nanofiber', 'system', 'ionic liquid', 'mechanism', and 'foot ulcer'. Three recent research subdivisions were identified via timeline visualization of references, particularly Clusters #0 'wound healing', #4 'situ mineralization', and #5 '3D bioprinter'. Insights derived from bibliometric analyses illustrate present conditions and trends in skin bioprinting research, potentially aiding researchers in pinpointing central themes and pioneering novel investigative approaches in this field.

Fabrication and characterization of an antibacterial chitosan-coated allantoin-loaded NaCMC/SA skin scaffold for wound healing applications

The field of tissue engineering has recently emerged as one of the most promising approaches to address the limitations of conventional tissue replacements for severe injuries. This study introduces a chitosan-coated porous skin scaffold based on sodium carboxymethyl cellulose (NaCMC) and sodium alginate (SA) hydrogels, incorporating allantoin (AL) as an antibacterial agent. The NaCMC/SA hydrogel was cross-linked with epichlorohydrin (ECH) and freeze-dried to obtain a three-dimensional porous structure. The coated and non-coated scaffolds underwent comprehensive evaluation and characterization through various in-vitro analyses, including SEM imaging, swelling, degradation, and mechanical assessments. Furthermore, the scaffolds were studied regarding their allantoin (AL) release profiles, antibacterial properties, cell viability, and cell adhesion. The in-vitro analyses revealed that adding a chitosan (CS) coating and allantoin (AL) to the NaCMC/SA hydrogel significantly improved the scaffolds' antibacterial properties and cell viability. It was observed that the NaCMC:SA ratio and ECH concentration influenced the swelling capacity, biodegradation, drug release profile, and mechanical properties of the scaffolds. Samples with higher NaCMC content exhibited enhanced swelling capacity, more controlled allantoin (AL) release, and improved mechanical strength. Furthermore, the in-vivo results demonstrated that the proposed skin scaffold exhibited satisfactory biocompatibility and supported cell viability during wound healing in Wistar rats, highlighting its potential for clinical applications.

In Situ Hydrogel Formulation for Advanced Wound Dressing: Influence of Co-Solvents and Functional Excipient on Tailored Alginate-Pectin-Chitosan Blend Gelation Kinetics, Adhesiveness, and Performance

Chronic skin wounds affect more than 40 million patients worldwide, representing a huge problem for healthcare systems. This study elucidates the optimization of an in situ gelling polymer blend powder for biomedical applications through the use of co-solvents and functional excipients, underlining the possibility of tailoring microparticulate powder properties to generate, in situ, hydrogels with advanced properties that are able to improve wound management and patient well-being. The blend was composed of alginate, pectin, and chitosan (APC). Various co-solvents (ethanol, isopropanol, and acetone), and salt excipients (sodium bicarbonate and ammonium carbonate) were used to modulate the gelation kinetics, rheology, adhesiveness, and water vapor transmission rate of the gels. The use of co-solvents significantly influenced particle size (mean diameter ranging from 2.91 to 5.05 µm), depending on the solvent removal rate. Hydrogels obtained using ethanol were able to absorb over 15 times their weight in simulated wound fluid within just 5 min, whereas when sodium bicarbonate was used, complete gelation was achieved in less than 30 s. Such improvement was related to the internal microporous network typical of the particle matrix obtained with the use of co-solvents, whereas sodium bicarbonate was able to promote the formation of allowed particles. Specific formulations demonstrated an optimal water vapor transmission rate, enhanced viscoelastic properties, gel stiffness, and adhesiveness (7.7 to 9.9 kPa), facilitating an atraumatic removal post-use with minimized risk of unintended removal. Microscopic analysis unveiled that porous inner structures were influencing fluid uptake, gel formation, and transpiration. In summary, this study provided valuable insights for optimizing tailored APC hydrogels as advanced wound dressings for chronic wounds, including vascular ulcers, pressure ulcers, and partial and full-thickness wounds, characterized by a high production of exudate.

Artificial dermis combined with skin grafting for the treatment of hand skin and soft tissue defects and exposure of bone and tendon

BACKGROUND

The recovery time of hand wounds is long, which can easily result in chronic and refractory wounds, making the wounds unable to be properly repaired. The treatment cycle is long, the cost is high, and it is prone to recurrence and disability. Double layer artificial dermis combined with autologous skin transplantation has been used to repair hypertrophic scars, deep burn wounds, exposed bone and tendon wounds, and post tumor wounds.

AIM

To investigate the therapeutic efficacy of autologous skin graft transplantation in conjunction with double-layer artificial dermis in treating finger skin wounds that are chronically refractory and soft tissue defects that expose bone and tendon.

METHODS

Sixty-eight chronic refractory patients with finger skin and soft tissue defects accompanied by bone and tendon exposure who were admitted from July 2021 to June 2022 were included in this study. The observation group was treated with double layer artificial dermis combined with autologous skin graft transplantation (n = 49), while the control group was treated with pedicle skin flap transplantation (n = 17). The treatment status of the two groups of patients was compared, including the time between surgeries and hospital stay. The survival rate of skin grafts/flaps and postoperative wound infections were evaluated using the Vancouver Scar Scale (VSS) for scar scoring at 6 mo after surgery, as well as the sensory injury grading method and two-point resolution test to assess the recovery of skin sensation at 6 mo. The satisfaction of the two groups of patients was also compared.

RESULTS

Wound healing time in the observation group was significantly longer than that in the control group (P < 0.05, 27.92 ± 3.25 d vs 19.68 ± 6.91 d); there was no significant difference in the survival rate of skin grafts/flaps between the two patient groups (P > 0.05, 95.1 ± 5.0 vs 96.3 ± 5.6). The interval between two surgeries (20.0 ± 4.3 d) and hospital stay (21.0 ± 10.1 d) in the observation group were both significantly shorter than those in the control group (27.5 ± 9.3 d) and (28.4 ± 17.7 d), respectively (P < 0.05). In comparison to postoperative infection (23.5%) and subcutaneous hematoma (11.8%) in the control group, these were considerably lower at (10.2%) and (6.1%) in the observation group. When comparing the two patient groups at six months post-surgery, the excellent and good rate of sensory recovery (91.8%) was significantly higher in the observation group than in the control group (76.5%) (P < 0.05). There was also no statistically significant difference in two point resolution (P > 0.05). The VSS score in the observation group (2.91 ± 1.36) was significantly lower than that in the control group (5.96 ± 1.51), and group satisfaction was significantly higher (P < 0.05, 90.1 ± 6.3 vs 76.3 ± 5.2).

CONCLUSION

The combination of artificial dermis and autologous skin grafting for the treatment of hand tendon exposure wounds has a satisfactory therapeutic effect. It is a safe, effective, and easy to operate treatment method, which is worthy of clinical promotion.

Preventing biological waste: Effective use of viable tissue in traumatized lower extremities

Severe open lower extremity trauma requires debridement to remove contamination and devitalized tissues. Aggressive debridement should be balanced with preservation of viable tissue. These often damaged but preserved viable tissues are "spare parts" that augment the options available for reconstruction. The long-term goal of reconstruction should be functional limb restoration and optimization. Injury patterns, levels, and patient factors will determine whether this endeavor is better accomplished with limb salvage or amputation. This article reviews the rationale and strategies for preserving spare parts throughout debridement and then incorporating them as opportunistic grafts in the ultimate reconstruction to facilitate healing and maximize extremity function.

Level of Evidence

5.

Rational Design of Immunomodulatory Hydrogels for Chronic Wound Healing

With all the advances in tissue engineering for construction of fully functional skin tissue, complete regeneration of chronic wounds is still challenging. Since immune reaction to the tissue damage is critical in regulating both the quality and duration of chronic wound healing cascade, strategies to modulate the immune system are of importance. Generally, in response to an injury, macrophages switch from pro-inflammatory to an anti-inflammatory phenotype. Therefore, controlling macrophages' polarization has become an appealing approach in regenerative medicine. Recently, hydrogels-based constructs, incorporated with various cellular and molecular signals, have been developed and utilized to adjust immune cell functions in various stages of wound healing. Here, the current state of knowledge on immune cell functions during skin tissue regeneration is first discussed. Recent advanced technologies used to design immunomodulatory hydrogels for controlling macrophages' polarization are then summarized. Rational design of hydrogels for providing controlled immune stimulation via hydrogel chemistry and surface modification, as well as incorporation of cell and molecules, are also dicussed. In addition, the effects of hydrogels' properties on immunogenic features and the wound healing process are summarized. Finally, future directions and upcoming research strategies to control immune responses during chronic wound healing are highlighted.

Plastic Surgery at War: A Scoping Review of Current Conflicts

INTRODUCTION

The scope of military plastic surgery and location where care is provided has evolved with each major conflict. To help inform plastic surgeon utilization in future conflicts, we conducted a review of military plastic surgery-related studies to characterize plastic surgeon contributions during recent military operations.

MATERIALS AND METHODS

Using a scoping review design, we searched electronic databases to identify articles published since September 1, 2001 related to military plastic surgery according to a defined search criterion. Next, we screened all abstracts for appropriateness based on pre-established inclusion/exclusion criteria. Finally, we reviewed the remaining full-text articles to describe the nature of care provided and the operational level at which care was delivered.

RESULTS

The final sample included 55 studies with most originating in the United States (54.5%) between 2005 and 2019 and were either retrospective cohort studies (81.8%) or case series (10.9%). The breadth of care included management of significant upper/lower extremity injuries (40%), general reconstructive and wound care (36.4%), and craniofacial surgery (16.4%). Microsurgical reconstruction was a primary focus in 40.0% of published articles. When specified, most care was described at Role 3 (25.5%) or Roles 4/5 facilities (62.8%) with temporizing measures more common at Role 3 and definite reconstruction at Roles 4/5. Several lessons learned were identified that held commonality across plastic surgery domain.

CONCLUSIONS

Plastic surgeons continue to play a critical role in the management of wounded service members, particularly for complex extremity reconstruction, craniofacial trauma, and general expertise on wound management. Future efforts should evaluate mechanisms to maintain these skill sets among military plastic surgeons.

Indications and functional outcome of the use of integra® dermal regeneration template for the management of traumatic soft tissue defects on dorsal hand, fingers and thumb

INTRODUCTION

Few studies have been conducted to explore the utility of the Integra^® dermal regeneration template (IDRT) combined with a delayed split-thickness skin graft (STSG) for reconstructing complex dorsal hand, digit, and thumb injuries. This study reports the indications and outcomes for 14 patients treated with this technique via a two-stage process.

MATERIALS AND METHODS

We retrospectively reviewed all patients treated by IDRT combined with STSG from May 2015 to October 2018. The inclusion criterion was traumatic or post-infectious soft tissue defects (STDs) of the dorsal hand, fingers, and thumb, not suitable for direct wound closure and requiring local, pedicle, or free flap reconstruction. After debridement, a two-stage procedure was applied, namely IDRT followed by STSG. Indications, functional outcomes, aesthetic results, complications, patient satisfaction, and the STSG take rate were evaluated over a 36-month follow-up using standardised instruments.

RESULTS

A total of 14 patients with 15 reconstructions (average age = 48 years) were included. The dominant hand was involved in 50% of cases. Dorsal STDs involved the hand, fingers, thumb, and hand and thumb in 7, 3, 2 and 2 cases, respectively. The mean STD size was 35 cm² (range: 3-150 cm²). The wound was associated with exposed tendons (without peritenon), bone (without periosteum), and joints (without a capsule) in eight cases (57%). The IDRT/STSG take rate was 97%. The average Vancouver Scar Scale score was 2 (1-4).

CONCLUSION

The 36-month follow-up demonstrated that IDRT is a safe and reliable technique that can be considered a viable alternative to flap reconstruction for the management of traumatic STDs in selected patients. The aesthetic outcomes are acceptable, functional recovery of the fingers is excellent, patient satisfaction is very high and the rate of complications is very low.

The Black Locust Tree: Toxalbumin-Induced Tissue Necrosis of the Upper Extremity

We present the case of a 48-year-old male who developed tissue necrosis and subsequent necrotizing fasciitis in his right upper extremity after sustaining a puncture injury from a large black locust tree (Robinia pseudoacacia) splinter. Blood and intraoperative wound cultures revealed Streptococcus constellatus and Eikenella corrodens infection. The treatment consisted of IV antibiotics, fasciotomy, and multiple debridements, which left a 30 x 5-cm defect, requiring negative pressure wound therapy with Integra Dermal Regeneration Template (Integra Lifesciences, Plainsboro Township, NJ) and, ultimately, split-thickness skin grafts. Although uncommon, plastic surgeons should be aware of tissue necrosis associated with robin toxalbumin in cases of black locust tree puncture wounds. Robin toxalbumin causes cellular death by inhibiting protein synthesis. In this patient, the toxalbumin from the black locust tree fragment led to extensive tissue necrosis, serving as the nidus for necrotizing fasciitis.

Adipose Stem Cells and Platelet-Rich Plasma Induce Vascular-Like Structures in a Dermal Regeneration Template

In the context of biointeractive dressings used for enhancing wound healing, the use of stromal vascular fraction (SVF) or adipose-derived stem cells (ASCs) hereof derived has not been fully exploited yet. Noncultured SVF, a heterogeneous mesenchymal population of cells, is attractive in the field of dermal regeneration because it can be instantaneously obtained, avoids genomic alterations, and is comparatively safer than cultured ASCs. Integra^® Dermal Regeneration Template (DRT) was sprinkled with ASCs in complete medium supplemented with 10% fetal bovine serum (FBS), or SVF, obtained from emulsified or nonemulsified fat, in medium supplemented with 2% platelet-rich plasma (PRP). The presence and differentiation of cells were evaluated by standard histochemistry and immunohistochemistry, whereas conditioned media were analyzed for vascular endothelial growth factors (VEGF) by ELISA. In vitro experiments were conducted to analyze ASC proliferation in the presence of either FBS or PRP. Deposition of ASCs in medium supplemented with FBS caused their integration into Integra DRT as early as 1 h. ASCs were found as aggregates until 6-10 days without forming organized structures. When seeded onto Integra DRT, SVF cells in medium supplemented with PRP formed aggregates at early times, which at 7 and 10 days organized into vascular-like structures, lined by CD31⁺ and smooth muscle actin-positive cells. With nonemulsified fat, the lacunar structures did not show an organized distribution of SVF cells. PRP induced ASC proliferation although at lower level than FBS. VEGF secretion was enhanced when fat emulsification was introduced into the protocol. In conclusion, the combination of SVF cells obtained from emulsified fat, PRP, and Integra DRT exhibit synergistic effect on the formation of vessel-like structures indicating a step forward aimed at regenerative surgery for chronic wound healing.

Silkworm Silk Matrices Coated with Functionalized Spider Silk Accelerate Healing of Diabetic Wounds

Complex cutaneous wounds like diabetic foot ulcers represent a critical clinical challenge and demand a large-scale and low-cost strategy for effective treatment. Herein, we use a rabbit animal model to investigate efficacy of bioactive wound dressings made up of silk biomaterials. Nanofibrous mats of Antheraea assama silkworm silk fibroin (AaSF) are coated with various recombinant spider silk fusion proteins through silk-silk interactions to fabricate multifunctional wound dressings. Two different types of spider silk coatings are used to compare their healing efficiency: FN-4RepCT (contains a cell binding motif derived from fibronectin) and Lac-4RepCT (contains a cationic antimicrobial peptide from lactoferricin). AaSF mats coated with spider silk show accelerated wound healing properties in comparison to the uncoated mats. Among the spider silk coated variants, dual coating of FN-4RepCT and Lac-4RepCT on top of AaSF mat demonstrated better wound healing efficiency, followed by FN-4RepCT and Lac-4RepCT single coated counterparts. The in vivo study also reveals excellent skin regeneration by the functionalized silk dressings in comparison to commercially used Duoderm dressing and untreated wounds. The spider silk coatings demonstrate early granulation tissue development, re-epithelialization, and efficient matrix remodelling of wounds. The results thus validate potential of bioactive silk matrices in faster repair of diabetic wounds.

A bioartificial dermal regeneration template promotes skin cell proliferation in vitro and enhances large skin wound healing in vivo

A novel bioartificial dermal regeneration template has been developed using platelet-rich plasma and acellular animal skin collagen sponge for the treatment of larger area and full thickness skin wounds. This platelet-rich plasma-collagen sponge keeps native skin structure and contains huge amounts of growth factors. The effect of this bioartificial dermal regeneration template was tested in vitro and in vivo via a mimic poor wound healing process by adding collagenase I into cell culture medium or the wound area. The in vitro experimental results indicated that the rat skin cells grew faster and produced more collagen in platelet-rich plasma-collagen sponge with collagenase than those treated either with collagen sponge plus collagenase, or collagenase, or control group without treatment. The in vivo experiments were performed by large rat skin wounds, 1.5 cm diameter, treated either with collagenase, or collagenase plus collagen sponge, or collagenase plus platelet-rich plasma-collagen sponge. The wound without treatment was used as a control. The wounds treated with collagenase-containing platelet-rich plasma-collagen sponge healed 4 times faster than the untreated wounds, 6 times faster than the collagenase treated wounds, 2.4 times faster than collagenase-containing collagen sponge treated wounds. The immunostaining indicated that the healed tissues in the wound areas treated with collagenase-containing platelet-rich plasma-collagen sponge were composed of collagen type I and collagen III with blood vessels and hair follicles. The results demonstrated that this collagenase-containing platelet-rich plasma-collagen sponge works as a bioartificial dermal regeneration template. The application of this collagenase-containing platelet-rich plasma-collagen sponge promotes the traumatic skin wound healing and permits the reconstitution of the inherent barrier functions of the skin.

Management of Mangled Extremities and Orthopaedic War Injuries

In 16 years of conflict, primarily in Iraq and Afghanistan, wounded warriors have primarily been subjected to blast type of injuries. Evacuation strategies have led to unprecedented survival rates in blast-injured soldiers, resulting in large numbers of wounded warriors with complex limb trauma. Bone and soft tissue defects have resulted in increased use of complex reconstructive algorithms to restore limbs and function. In addition, in failed salvage attempts, advances in amputation options are being developed. In this review, we summarize state-of-the-art limb-salvage methods for both soft tissue and bone. In addition, we discuss advances in diagnostic methods with development of personalized clinical decision support tools designed to optimize outcomes after severe blast injuries. Finally, we present new advances in osteointegrated prostheses for above-knee amputations.

A Case Report of the First Nonburn-related Military Trauma Victim Treated with Spray Skin Regenerative Therapy in Combination with a Dermal Regenerate Template

Massive soft tissue and skin loss secondary to war-related traumas are among the most frequently encountered challenges in the care of wounded warriors. This case report outlines the first military nonburn-related trauma patient treated by a combination of regenerative modalities. Our case employs spray skin technology to an established dermal regenerate matrix. Our patient, a 29-year-old active duty male, suffered a combat blast trauma in 2010 while deployed. The patient’s treatment course was complicated by a severe necrotizing fasciitis infection requiring over 100 surgical procedures for disease control and reconstruction. In secondary delayed reconstruction procedures, this triple-limb amputee underwent successful staged ventral hernia repair via a component separation technique with biologic mesh underlay although this resulted in a skin deficit of more than 600 cm². A dermal regenerate template was applied to the abdominal wound to aid in establishing a “neodermis.” Three weeks after dermal regenerate application, spray skin was applied to the defect in conjunction with a 6:1 meshed split thickness skin graft. The dermal regenerate template allowed for optimization of the wound bed for skin grafting. The use of spray skin allowed for a 6:1 mesh ratio, thus minimizing the donor-site size and morbidity. Together, this approach resulted in complete healing of a large full-thickness wound. The patient is now able to perform activities of daily living, walk without a cane, and engage in various physical activities. Overall, our case highlights the potential that combining regenerative therapies can achieve in treating severe war-related and civilian traumatic injuries.

Use of a Dermal Regeneration Template Wound Dressing in the Treatment of Combat-Related Upper Extremity Soft Tissue Injuries

PURPOSE

To assess the outcomes of treatment with a dermal regeneration template (DRT) in a cohort of combat casualties with severe upper extremity injuries.

METHODS

Records of all active duty military patients treated with DRT at our institution between November 2009 and July 2013 were screened. Inclusion criteria were upper extremity open wounds sustained during combat, requiring split-thickness or full-thickness skin grafting for closure. The primary outcome measure was wound healing after the first attempt at definitive treatment (defined as the first application of split-thickness or full-thickness skin graft). Independent variables collected included time from injury to arrival at our facility, mechanism of injury, wound infection, tobacco use, location of wound, number of operative debridements, and patient demographics.

RESULTS

A total of 60 patients with 69 wounds met the inclusion criteria. Most wounds were to the wrist or forearm (54%) or fingers (19%). All wounds were heavily contaminated, requiring a mean of 2.5 operative debridements before DRT placement. All wounds treated with full-thickness skin grafting after DRT healed completely without further complication. Split-thickness skin grafting was successful in 96% of patients.

CONCLUSIONS

DRT wound dressings are a helpful adjunct in the treatment of contaminated war wounds to the upper extremity.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Use of bioartificial dermal regeneration template for skin restoration in combat casualty injuries

A letter in response to: Seavey JG, Masters ZA, Balazs GC, Tintle SM, Sabino J, Fleming ME & Valerio IL. Use of bioartificial dermal regeneration template for skin restoration in combat casualty injuries. Regen. Med. 11(1), 81-90 (2016).