Progress towards cell-based burn wound treatments

Comparative Analysis of Animal-Derived vs Fully Synthetic Acellular Dermal Matrices in Reconstructive Surgery: An Examination of Clinical, Aesthetic, and Economic Measures

INTRODUCTION

The fully synthetic skin substitute, NovoSorb Biodegradable Temporizing Matrix (BTM), may be a cost-effective alternative to the animal-derived Integra Dermal Regeneration Template (IDRT). However, the current literature insufficiently compares the two. Therefore, our study compared clinical, aesthetic, and economic outcomes in treating soft tissue wounds with IDRT, an animal-derived template, vs BTM, a fully synthetic template.

METHODS

Our single-center retrospective study compared outcomes of 26 patient cases treated with BTM (57.7%) or IDRT (42.3%) during 2011-2022.

RESULTS

The mean surgery time was significantly shorter in BTM cases (1.632 ± 0.571 hours) compared with IDRT cases (5.282 ± 5.102 hours, P = 0.011). Median postoperative hospital stay was notably shorter for BTM placement than IDRT placement (0.95 vs 6.60 days, P = 0.003). The median postoperative follow-up length approached a shorter duration in the BTM group (P = 0.054); however, median follow-up visits were significantly lower in the BTM group compared with the IDRT group (5 vs 14, P = 0.012). The median duration for complete wound closure was shorter for BTM (46.96 vs 118.91 days, P = 0.011). Biodegradable Temporizing Matrix demonstrated a notably lower infection rate (0.0%) compared with IDRT (36.4%, P = 0.022). Integra Dermal Regeneration Template exhibited higher wound hypertrophy rates (81.8%) than BTM (26.7%, P = 0.015). Revisionary surgeries were significantly more frequent in the BTM group (P < 0.001). Failed closure, defined as requiring one or more attempts, exhibited a significant difference, with a higher risk in the IDRT group (26.7%) compared with BTM (6.7%, P = 0.003). Biodegradable Temporizing Matrix showed a lower mean Vancouver Scar Scale adjusted fraction (0.279) compared with IDRT (0.639, P < 0.001). Biodegradable Temporizing Matrix incurred lower costs compared with IDRT but displayed a lower mean profit per square centimeter ($10.63 vs $22.53, P < 0.001).

CONCLUSION

Economically, although the net profit per square centimeter of dermal template may favor IDRT, the ancillary benefits associated with BTM in terms of reduced hospital stay, shorter surgery times, fewer follow-up visits, and lower revisionary surgery rates contribute substantially to overall cost-effectiveness. Biodegradable Temporizing Matrix use reflects more efficient resource use and potential cost savings, aligning with broader trends in healthcare emphasizing value-based and patient-centered care.

Role of Cultured Skin Fibroblasts in Regenerative Dermatology

The skin, as the largest organ, covers the entire outer part of the body, and since this organ is directly exposed to microbial, thermal, mechanical and chemical damage, it may be destroyed by factors such as acute trauma, chronic wounds or even surgical interventions. Cell therapy is one of the most important procedures to treat skin lesions. Fibroblasts are cells that are responsible for the synthesis of collagen, elastin, and the organization of extracellular matrix (ECM) components and have many vital functions in wound healing processes. Today, cultured autologous fibroblasts are used to treat wrinkles, scars, wounds and subcutaneous atrophy. The results of many studies have shown that fibroblasts can be effective and beneficial in the treatment of skin lesions. On the other hand, skin substitutes are used as a regenerative model to improve and regenerate the skin. The use of these alternatives, restorative medicine and therapeutic cells such as fibroblasts has tremendous potential in the treatment of skin diseases and can be a new window for the treatment of diseases with no definitive treatment. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description ofthese Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Biological Effects of Maslinic Acid on Human Epithelial Cells Used in Tissue Engineering

In the present work, we evaluated the potential of maslinic acid (MA) to improve currently available keratinocyte culture methods for use in skin tissue engineering. Results showed that MA can increase cell proliferation and WST-1 activity of human keratinocytes after 24, 48, and 72 h, especially at the concentration of 5 μg/ml, without affecting cell viability. This effect was associated to a significant increase of KI-67 protein expression and upregulation of several genes associated to cell proliferation (PCNA) and differentiation (cytokeratins, intercellular junctions and basement membrane related genes). When human keratinocytes were isolated from skin biopsies, we found that MA at the concentration of 5 μg/ml significantly increased the efficiency of the explant and the cell dissociation methods. These results revealed the positive effects of MA to optimize human keratinocyte culture protocols for use in skin tissue engineering.

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

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

Dermal Fibroblast Heterogeneity and Its Contribution to the Skin Repair and Regeneration

Significance: Dermal fibroblasts are the major cell type in the skin's dermal layer. These cells originate from distinct locations of the embryo and reside in unique niches in the dermis. Different dermal fibroblasts exhibit distinct roles in skin development, homeostasis, and wound healing. Therefore, these cells are becoming attractive candidates for cell-based therapies in wound healing. Recent Advances: Human skin dermis comprises multiple fibroblast subtypes, including papillary, reticular, and hair follicle-associated fibroblasts, and myofibroblasts after wounding. Recent studies reveal that these cells play distinct roles in wound healing and contribute to diverse healing outcomes, including nonhealing chronic wound or excessive scar formation, such as hypertrophic scars (HTS) and keloids, with papillary fibroblasts having antiscarring and reticular fibroblast scar-forming properties. Critical Issues: The identities and functions of dermal fibroblast subpopulations in many respects remain unknown. In this review, we summarize the current understanding of dermal fibroblast heterogeneity, including their defined cell markers and dermal niches, dynamic changes, and contributions to skin wound healing, with the emphasis on scarless healing, healing with excessive scars (HTS and keloids), chronic wounds, and the potential application of this heterogeneity for developing cell-based therapies that allow wounds to heal faster with less scarring. Future Directions: Heterogeneous dermal fibroblast populations and their functions are poorly characterized. Refining and advancing our understanding of dermal fibroblast heterogeneity and their participation in skin homeostasis and wound healing may create potential therapeutic applications for nonhealing chronic wounds or wounds that heal with excessive scarring.

Healing of deep dermal burns by allogeneic mesenchymal stromal cell transplantation

BACKGROUND

Deep dermal and full-thickness burns are not only difficult to treat, but they are also associated with significant morbidity and mortality. Recent reports have proposed the use of mesenchymal stromal cells (MSCs) for inducing tissue repair in burn injuries.

OBJECTIVE

We aim to evaluate the effect of allogeneic MSC transplantation on full-thickness burns with delayed healing.

MATERIAL AND METHODS

This study includes five patients with AB B/B burns. All patients received conservative treatments, including cleaning, debridement of necrotic tissue, and silver based dressing on the burn wounds. Cryopreserved allogeneic MSCs were thawed and rapidly expanded and used for application in burned patients. MSCs were implanted into preclotted platelet-rich plasma onto the surface of burn wounds.

RESULTS

All treated burn wounds showed early granulation tissue and rapid re-epithelialization after MSC transplantation. Healing took between 1 and 5 months after MSC transplantation. Repair of burn wounds was associated with slight discoloration of the regenerated skin without hypertrophic scarring or contractures.

CONCLUSION

Our results provide evidence of healing in deep- and full-thickness burns by allogeneic MSC transplantation. Rapid healing of burn patients, after MSC transplantation, improves their quality of life and reduces the length of hospitalization. Future studies incorporating a larger number of patients may confirm the results obtained in this work.

Keratinocyte sheets prepared with temperature-responsive dishes show enhanced survival after in vivo grafting on acellular dermal matrices in a rat model of staged bi-layered skin reconstruction

Introduction

Bi-layered skin reconstruction can be achieved by staged grafting of acellular dermal matrices (ADMs) and cultured epithelial keratinocyte sheets (KSs). Both KSs and ADMs have been used for long; yet, their combined use has shown poor effectiveness. This outcome has been related to the enzymatic treatment used in the preparation of KSs, which impairs their adhesion potential to ADMs and the formation of a basement membrane (BM). Temperature-responsive (TR) culture dishes allow for enzyme-free preparation of KSs with preservation of BMs and intercellular adhesion proteins; yet, their use has not been previously applied to staged bi-layered skin reconstruction. Using an in vivo rat model, we tested the hypothesis that TR cultures enhance KSs survival and BM preservation after sequential grafting on ADMs.

Methods

In nude rats (n = 9/group), a 9-cm [2] full-thickness dorsal skin defect was repaired with a commercial ADM. At 2 weeks after surgery, we grafted the ADM with KSs (circular, 25 mm diameter), prepared from human cells either by enzymatic Dispase treatment (DT control group) or a TR culture dish (TR experimental group). KSs survival and BMs preservation was assessed one week later by digital imaging, histology (hematoxylin & eosin), immunohistochemistry (collagen IV, pancytokeratins) and immunofluorescence (cytokeratin 1-5-6, laminin).

Results

The TR group showed a significantly higher KSs survival (120 ± 49 vs. 63 ± 42 mm²; p < 0.05) and epidermal thickness (165 ± 79 vs. 65 ± 54 μm; p < 0.01) compared with the control DT group, as well as higher epidermal maturation (cytokeratin) and a denser laminin and Collagen IV expression in the BMs in vitro and in vivo.

Conclusion

These findings suggest that KSs prepared with TR culture dishes have significantly enhanced survival when grafted on ADMs; these outcomes could help improve current clinical strategies in wound care by skin reconstruction.

Advances in keratinocyte delivery in burn wound care

This review gives an updated overview on keratinocyte transplantation in burn wounds concentrating on application methods and future therapeutic cell delivery options with a special interest in hydrogels and spray devices for cell delivery. To achieve faster re-epithelialisation of burn wounds, the original autologous keratinocyte culture and transplantation technique was introduced over 3 decades ago. Application types of keratinocytes transplantation have improved from cell sheets to single-cell solutions delivered with a spray system. However, further enhancement of cell culture, cell viability and function in vivo, cell carrier and cell delivery systems remain themes of interest. Hydrogels such as chitosan, alginate, fibrin and collagen are frequently used in burn wound care and have advantageous characteristics as cell carriers. Future approaches of keratinocyte transplantation involve spray devices, but optimisation of application technique and carrier type is necessary.

The role of bone marrow mesenchymal stromal cell derivatives in skin wound healing in diabetic mice

Mesenchymal stromal cells (MSCs) have shown to be a promising tool in cell therapies to treat different conditions. Several pre-clinical and clinical studies have proved that the transplantation of MSCs improves wound healing. Here, we compare the beneficial effects of mouse bone marrow-derived allogeneic MSCs (allo-mBM-MSCs) and their acelullar derivatives (allo-acd-mMSCs) on skin wound healing in Non-Obese Diabetic (NOD) mice. One dose of allo-mBM-MSCs (1×106 cells) or one dose of allo-acd-mMSCs (1X) were intradermally injected around wounds in 8-10 week old female NOD mice. Wound healing was evaluated macroscopically (wound closure) every two days, and microscopically (reepithelialization, dermoepidermal junction, skin appendage regeneration, leukocyte infiltration, vascularization, granulation tissue formation, and density of collagen fibers in the dermis) after 16 days of MSC injection. In addition, we measured growth factors and specific proteins that were present in the allo-acd-mMSCs. Results showed significant differences in the wound healing kinetics of lesions that received allo-acd-mMSCs compared to lesions that received vehicle or allo-mBM-MSCs. In particular, mice treated with allo-acd-mMSCs reached significantly higher percentages of wound closure at day 4, 6 and 8, relative to the allo-mBM-MSCs and vehicle groups (p < 0.05), while wound closure percentages could not be statistically distinguished between the allo-mBM-MSCs and vehicle groups. Also, allo-acd-mMSCs had a greater influence in the skin would healing process. Specifically, they caused a less pronounced inflammatory severe response (p < 0.0001), more granulation tissue formation at an advanced stage (p < 0.0001), and higher density of collagen fibers (p < 0.05) compared to the other groups. Nevertheless, at day 16, both allo-mBM-MSCs and allo-acd-mMSCs revealed a higher effect on the recovery of the quality skin (continuous epidermis; regular dermoepidermal junction and skin appendages) relative to untreated lesions (p < 0.0001), but not between them. On the other hand, ELISA analyses indicated that the allo-acd-mMSCs contained growth factors and proteins relevant to wound healing such as IGF-1, KGF, HGF, VEGF, ANG-2, MMP-1, CoL-1 and PGE2. Compared to allo-acd-mMSCs, the administration of allo-mBM-MSCs is insufficient for wound healing in diabetic mice and delays the therapeutic effect, which maybe explained by the fact that trophic factors secreted by MSCs are critical for skin regeneration, and not the cells per se, suggesting that MSCs may require some time to secrete these factors after their administration.

Diverging Concepts and Novel Perspectives in Regenerative Medicine

Regenerative medicine has rapidly evolved, due to progress in cell and molecular biology allowing the isolation, characterization, expansion, and engineering of cells as therapeutic tools. Despite past limited success in the clinical translation of several promising preclinical results, this novel field is now entering a phase of renewed confidence and productivity, marked by the commercialization of the first cell therapy products. Ongoing issues in the field include the use of pluripotent vs. somatic and of allogenic vs. autologous stem cells. Moreover, the recognition that several of the observed beneficial effects of cell therapy are not due to integration of the transplanted cells, but rather to paracrine signals released by the exogenous cells, is generating new therapeutic perspectives in the field. Somatic stem cells are outperforming embryonic and induced pluripotent stem cells in clinical applications, mainly because of their more favorable safety profile. Presently, both autologous and allogeneic somatic stem cells seem to be equally safe and effective under several different conditions. Recognition that a number of therapeutic effects of transplanted cells are mediated by paracrine signals, and that such signals can be found in extracellular vesicles isolated from culture media, opens novel therapeutic perspectives in the field of regenerative medicine.

Adipose-Derived Regenerative Cell Therapy for Burn Wound Healing: A Comparison of Two Delivery Methods

Objective: The use of noncultured autologous stromal vascular fraction or clinical grade adipose-derived regenerative cells (ADRCs) is a promising strategy to promote wound healing and tissue repair. Nevertheless, issues regarding the optimal mode of administration remain unclear. The purpose of this study was to compare the effects of local injection and topical spray delivery of ADRCs in a porcine model of thermal burns. Approach: Full-thickness thermal burns were created on the dorsum of 10 Gottingen minipigs. Two days following injury, wounds underwent fascial excision and were randomized to receive control vehicle or freshly isolated autologous ADRCs delivered by either multiple injections into or surrounding the wound bed, or by spray onto the wound surface (0.25 × 10⁶ viable cells/cm²). Healing was evaluated by planimetry, histopathology, and immunohistochemistry at day 7, 12, 16, 21, and 28 posttreatment. Results:In vitro analysis demonstrated that there was no substantial loss of cell number or viability attributable to the spray procedure. Planimetric assessment revealed that delivery of ADRCs by either local injection or topical spray increased wound reepithelialization relative to control at day 14. No significant difference in wound reepithelialization was observed between both delivery approaches. In addition, on day 7 posttreatment, blood vessel density was greater in wounds receiving local or topical spray ADRCs than in the wounds treated with vehicle control. Histopathologic analysis suggests that ADRC treatment may modulate the inflammatory response by reducing neutrophil infiltration at day 7 and 12 posttreatment, irrespective of the route of administration. Conclusions: These data demonstrate that local injection and spray delivery of ADRCs modulate inflammation and improve wound angiogenesis and epithelialization. Importantly, both delivery routes exhibited similar effects on wound healing. Given the greater ease-of-use associated with topical spray delivery, these data support the use of a spray system for autologous ADRC delivery.

Substance P combined with epidermal stem cells promotes wound healing and nerve regeneration in diabetes mellitus

Exogenous substance P accelerates wound healing in diabetes, but the mechanism remains poorly understood. Here, we established a rat model by intraperitoneally injecting streptozotocin. Four wounds (1.8 cm diameter) were drilled using a self-made punch onto the back, bilateral to the vertebral column, and then treated using amniotic membrane with epidermal stem cells and/or substance P around and in the middle of the wounds. With the combined treatment the wound-healing rate was 100% at 14 days. With prolonged time, type I collagen content gradually increased, yet type III collagen content gradually diminished. Abundant protein gene product 9.5- and substance P-immunoreactive nerve fibers regenerated. Partial nerve fiber endings extended to the epidermis. The therapeutic effects of combined substance P and epidermal stem cells were better than with amniotic membrane and either factor alone. Our results suggest that the combination of substance P and epidermal stem cells effectively contributes to nerve regeneration and wound healing in diabetic rats.

3D Printing of Scaffold for Cells Delivery: Advances in Skin Tissue Engineering

Injury or damage to tissue and organs is a major health problem, resulting in about half of the world’s annual healthcare expenditure every year. Advances in the fields of stem cells (SCs) and biomaterials processing have provided a tremendous leap for researchers to manipulate the dynamics between these two, and obtain a skin substitute that can completely heal the wounded areas. Although wound healing needs a coordinated interplay between cells, extracellular proteins and growth factors, the most important players in this process are the endogenous SCs, which activate the repair cascade by recruiting cells from different sites. Extra cellular matrix (ECM) proteins are activated by these SCs, which in turn aid in cellular migrations and finally secretion of growth factors that can seal and heal the wounds. The interaction between ECM proteins and SCs helps the skin to sustain the rigors of everyday activity, and in an attempt to attain this level of functionality in artificial three-dimensional (3D) constructs, tissue engineered biomaterials are fabricated using more advanced techniques such as bioprinting and laser assisted printing of the organs. This review provides a concise summary of the most recent advances that have been made in the area of polymer bio-fabrication using 3D bio printing used for encapsulating stem cells for skin regeneration. The focus of this review is to describe, in detail, the role of 3D architecture and arrangement of cells within this system that can heal wounds and aid in skin regeneration.

Synthetic Biology: Rational Pathway Design for Regenerative Medicine

Rational pathway design is the invention of an optimally efficient route from one state (e.g. chemical structure, state of differentiation, physiological state) to another, based on knowledge of biological processes: it contrasts with the use of natural pathways that have evolved by natural selection. Synthetic biology is a hybrid discipline of biology and engineering that offers a means for rationally designed pathways to be realized in living cells. Several areas of regenerative medicine could benefit from rational pathway design, including derivation of patient-specific stem cells, directed differentiation of stem cells, replicating physiological function in an alternative cell type, construction of custom interface tissues and building fail-safe systems into transplanted tissues. Synthetic biological approaches offer the potential for construction of these, for example controllable ex vivo stem cell niches, genetic networks for direct transdifferentiation from adult fibroblast to restricted stem cell without going via induced pluripotent stem cells, signalling pathways for realizing physiological regulation in alternative cell types, morphological modules for producing self-constructing novel 'tissues' and 'kill-switches' for therapeutically applied stem cells. Given the potential of this approach, a closer convergence of the regenerative medicine and synthetic biology research fields seems timely.

Tissue engineering in burn scar reconstruction

Nowadays, most patients with severe burns will survive their injury. This evolution is accompanied by the challenge to cover a large percentage of total body surface area burned. Consequently, more and more patients have to deal with the sequelae of burn scars and require (multiple) reconstructions. This review provides a gross overview of developments in the field of tissue engineering for permanent burn wound coverage and reconstructive burn surgery, focusing on usage and clinical effectiveness. Not only skin substitutes will be discussed but also the replacement of subcutaneous fat tissue and cartilage.

Outcome of Burns Treated With Autologous Cultured Proliferating Epidermal Cells: A Prospective Randomized Multicenter Intrapatient Comparative Trial

Standard treatment for large burns is transplantation with meshed split skin autografts (SSGs). A disadvantage of this treatment is that healing is accompanied by scar formation. Application of autologous epidermal cells (keratinocytes and melanocytes) may be a suitable therapeutic alternative, since this may enhance wound closure and improve scar quality. A prospective, multicenter randomized clinical trial was performed in 40 adult patients with acute full thickness burns. On two comparable wound areas, conventional treatment with SSGs was compared to an experimental treatment consisting of SSGs in combination with cultured autologous epidermal cells (ECs) seeded in a collagen carrier. The primary outcome measure was wound closure after 5-7 days. Secondary outcomes were safety aspects and scar quality measured by graft take, scar score (POSAS), skin colorimeter (DermaSpectrometer) and elasticity (Cutometer). Wound epithelialization after 5-7 days was significantly better for the experimental treatment (71%) compared to the standard treatment (67%) (p = 0.034, Wilcoxon), whereas the take rates of the grafts were similar. No related adverse events were recorded. Scar quality was evaluated at 3 (n = 33) and 12 (n = 28) months. The POSAS of the observer after 3 and 12 months and of the patient after 12 months were significantly better for the experimental area. Improvements between 12% and 23% (p ≤ 0.010, Wilcoxon) were detected for redness, pigmentation, thickness, relief, and pliability. Melanin index at 3 and 12 months and erythema index at 12 months were closer to normal skin for the experimental treatment than for conventional treatment (p ≤ 0.025 paired samples t-test). Skin elasticity showed significantly higher elasticity (p = 0.030) in the experimental area at 3 months follow-up. We showed a safe application and significant improvements of wound healing and scar quality in burn patients after treatment with ECs versus SSGs only. The relevance of cultured autologous cells in treatment of extensive burns is supported by our current findings.

Ex vivo evaluation of acellular and cellular collagen-glycosaminoglycan flowable matrices

Collagen-glycosaminoglycan flowable matrices (CGFM) are increasingly finding utility in a diversifying number of cutaneous surgical procedures. Cellular in-growth and vascularisation of CGFM remain rate-limiting steps, increasing cost and decreasing efficacy. Through in vitro and ex vivo culture methods, this study investigated the improvement of injectable CGFM by the incorporation of hyaluronan (HA) and viable human cells (primary human dermal fibroblasts (PHDFs) and bone marrow-derived mesenchymal stem cells (BM-MSCs)). Ex vivo investigations included the development and evaluation of a human cutaneous wound healing model for the comparison of dermal substitutes. Cells mixed into the Integra Flowable Wound Matrix (IFWM), a commercially available CGFM, were confirmed to be viable and proliferative through MTT assays (p  <  0.05). PHDFs proliferated with greater rapidity than BM-MSCs up to 1 week in culture (p  <  0.05), with PHDF proliferation further enhanced by HA supplementation (p  <  0.05). After scaffold mixing, gene expression was not significantly altered (qRT-PCR). PHDF and BM-MSC incorporation into ex vivo wound models significantly increased re-epithelialisation rate, with maximal effects observed for BM-MSC supplemented IFWM. HA supplementation to PHDF populated IFWM increased re-epithelialisation but had no significant effect on BM-MSC populated IFWM. In conclusion, when combined with PHDF, HA increased re-epithelialisation in IFWM. BM-MSC incorporation significantly improved re-epithelialisation in ex vivo models over acellular and PHDF populated scaffolds. Viable cell incorporation into IFWM has potential to significantly benefit wound healing in chronic and acute cutaneous injuries by allowing a point-of-care matrix to be formed from autologous or allogenic cells and bioactive molecules.

History of burns: The past, present and the future

Burn injuries are one of the most common and devastating afflictions on the human body. In this article we look back at how the treatment of burns has evolved over the centuries from a primarily topical therapy consisting of weird and wonderful topical concoctions in ancient times to one that spans multiple scientific fields of topical therapy, antibiotics, fluid resuscitation, skin excision and grafting, respiratory and metabolic care and nutrition. Most major advances in burn care occurred in the last 50 years, spurred on by wars and great fires. The use of systemic antibiotics and topical silver therapy greatly reduced sepsis related mortality. This along with the advent of antiseptic surgical techniques, burn depth classification and skin grafting allowed the excision and coverage of full-thickness burns which resulted in greatly improved survival rates. Advancements in the methods of assessing the surface area of burns paved way for more accurate fluid resuscitation, minimising the effects of shock and avoiding fluid over-loading. The introduction of metabolic care, nutritional support and care of inhalational injuries further improved the outcome of burn patients. We also briefly discuss some future directions in burn care such as the use of cell and pharmalogical therapies.