Correction: Paracrine Factors of Mesenchymal Stem Cells Recruit Macrophages and Endothelial Lineage Cells and Enhance Wound Healing.

[This corrects the article DOI: 10.1371/journal.pone.0001886.].

The effects of TGF-ß1 and IFN-α2b on decorin, decorin isoforms and type I collagen in hypertrophic scar dermal fibroblasts.

Hypertrophic scars (HTS) develop from an excessive synthesis of structural proteins like collagen and a decreased expression of proteoglycans such as decorin. Previous research has demonstrated that decorin expression is significantly down-regulated in HTS, deep dermal tissue, and thermally injured tissue, reducing its ability to regulate pro-fibrotic transforming growth factor-beta 1 (TGF-ß1) and normal fibrillogenesis. However, treatment of HTS fibroblasts with interferon-alpha 2b (IFN-α2b) has been shown to reduce excessive collagen synthesis and improve HTS by reducing serum TGF-ß1 levels. The expression of decorin isoforms in HTS is currently unknown and the effects of TGF-ß1 and IFN-α2b on decorin, decorin isoform expression and type 1 collagen are of great interest to our group. Dermal fibroblasts were treated with TGF-ß1 and/or IFN-α2b, for 48 h. The expression and secretion of decorin, decorin isoforms and type 1 collagen were quantified with reverse transcription-quantitative polymerase chain reaction, immunofluorescence staining and enzyme-linked immunosorbent assays. The mRNA expression of decorin and each isoform was significantly reduced in HTS fibroblasts relative to normal skin. TGF-ß1 decreased the mRNA expression of decorin and decorin isoforms, whereas IFN-α2b showed the opposite effect. IFN-α2b significantly inhibited TGF-ß1's effect on the mRNA expression of type I collagen alpha 1 in papillary dermal fibroblasts and overall showed relative effects of inhibiting TGF-ß1. These data support that a further investigation into the structural and functional roles of decorin isoforms in HTS pathogenesis is warranted and that IFN-α2b is an important agent in reducing fibrotic outcomes.

Serial Casting as an Effective Method for Burn Scar Contracture Rehabilitation: A Case Series.

Guidelines and protocols for orthoses in burn scar contracture rehabilitation are limited. The current study aims to determine the optimal frequency of casting, potentially facilitating the development of a serial casting protocol. Previous literature supporting casting has low generalizability due to methodology limitations. Seven patients with burn scar contracted joints, who did not respond to traditional therapy, were recruited in this study. Patients were serially casted once, three times, or five times a week. Joint range of motion was maximized with stretching and exercise techniques before every new cast application. Across all patients, active range of motion increased from 65.8 ± 27.8° to 108.1 ± 23.3° with casting; or from 57.8 ± 16.2% to 96.7 ± 2.9% of normal. Similarly, scars improved from 9.5 ± 1.5 to 4.9 ± 1.4 on the Modified Vancouver Scar Scale score. This therapeutic effect was achieved within an average of 8.5 ± 3.7 d and 4.0 ± 2.2 new cast applications. Given the study findings, the procedures outlined could be used to develop a standardized serial casting protocol for burn scar contracture rehabilitation.

An Engineered Dermal Substitute with Mesenchymal Stem Cells Enhances Cutaneous Wound Healing.

The treatment of refractory cutaneous wounds remains to be a clinical challenge. There is growing evidence to show that mesenchymal stem cells (MSCs) have great potential in promoting wound healing. However, the therapeutic effects of MSCs are greatly dampened by their poor survival and engraftment in the wounds. To address this limitation, in this study, MSCs were grown into a collagen-glycosaminoglycan (C-GAG) matrix to form a dermis-like tissue sheet, named engineered dermal substitute (EDS). When seeded on C-GAG matrix, MSCs adhered rapidly, migrated into the pores, and proliferated readily. When applied onto excisional wounds in healthy and diabetic mice, the EDS survived well, and accelerated wound closure, compared with C-GAG matrix alone or MSCs in collagen hydrogel. Histological analysis revealed that EDS prolonged the retention of MSCs in the wounds, associated with increased macrophage infiltration and enhanced angiogenesis. RNA-Seq analysis of EDS-treated wounds uncovered the expression of abundant human chemokines and proangiogenic factors and their corresponding murine receptors, suggesting a mechanism of ligand/receptor-mediated signals in wound healing. Thus, our results indicate that EDS prolongs the survival and retention of MSCs in the wounds and enhances wound healing.

Injury-induced interleukin-1 alpha promotes Lgr5 hair follicle stem cells de novo regeneration and proliferation via regulating regenerative microenvironment in mice.

BACKGROUND: The hair follicles (HFs) are barely regenerated after loss in injuries in mammals as well as in human beings. Recent studies have shown that the regenerative ability of HFs is age-related; however, the relationship between this phenomenon and the stem cell niche remains unclear. This study aimed to find a key secretory protein that promotes the HFs regeneration in the regenerative microenvironment. METHODS: To explore why age affects HFs de novo regeneration, we established an age-dependent HFs regeneration model in leucine-rich repeat G protein-coupled receptor 5 (Lgr5) + /mTmG mice. Proteins in tissue fluids were analyzed by high-throughput sequencing. The role and mechanism of candidate proteins in HFs de novo regeneration and hair follicle stem cells (HFSCs) activation were investigated through in vivo experiments. The effects of candidate proteins on skin cell populations were investigated by cellular experiments. RESULTS: Mice under 3-week-old (3W) could regenerate HFs and Lgr5 HFSCs, which were highly correlated with the immune cells, cytokines, IL-17 signaling pathway, and IL-1α level in the regeneration microenvironment. Additionally, IL-1α injection induced de novo regeneration of HFs and Lgr5 HFSCs in 3W mouse model with a 5 mm wound, as well as promoted activation and proliferation of Lgr5 HFSCs in 7-week-old (7W) mice without wound. Dexamethasone and TEMPOL inhibited the effects of IL-1α. Moreover, IL-1α increased skin thickness and promoted the proliferation of human epidermal keratinocyte line (HaCaT) and skin-derived precursors (SKPs) in vivo and in vitro, respectively. CONCLUSIONS: In conclusion, injury-induced IL-1α promotes HFs regeneration by modulating inflammatory cells and oxidative stress-induced Lgr5 HFSCs regeneration as well as promoting skin cell populations proliferation. This study uncovers the underlying molecular mechanisms enabling HFs de novo regeneration in an age-dependent model.

Burn Resuscitation Practices in North America: Results of the Acute Burn ResUscitation Multicenter Prospective Trial (ABRUPT).

OBJECTIVES: ABRUPT was a prospective, noninterventional, observational study of resuscitation practices at 21 burn centers. The primary goal was to examine burn resuscitation with albumin or crystalloids alone, to design a future prospective randomized trial. SUMMARY BACKGROUND DATA: No modern prospective study has determined whether to use colloids or crystalloids for acute burn resuscitation. METHODS: Patients ≥18 years with burns ≥ 20% total body surface area (TBSA) had hourly documentation of resuscitation parameters for 48 hours. Patients received either crystalloids alone or had albumin supplemented to crystalloid based on center protocols. RESULTS: Of 379 enrollees, two-thirds (253) were resuscitated with albumin and one-third (126) were resuscitated with crystalloid alone. Albumin patients received more total fluid than Crystalloid patients (5.2 ± 2.3 vs 3.7 ± 1.7 mL/kg/% TBSA burn/24 hours), but patients in the Albumin Group were older, had larger burns, higher admission Sequential Organ Failure Assessment (SOFA) scores, and more inhalation injury. Albumin lowered the in-to-out (I/O) ratio and was started ≤12 hours in patients with the highest initial fluid requirements, given >12 hours with intermediate requirements, and avoided in patients who responded to crystalloid alone. CONCLUSIONS: Albumin use is associated with older age, larger and deeper burns, and more severe organ dysfunction at presentation. Albumin supplementation is started when initial crystalloid rates are above expected targets and improves the I/O ratio. The fluid received in the first 24 hours was at or above the Parkland Formula estimate.

Advantages and Disadvantages of Using Small and Large Animals in Burn Research: Proceedings of the 2021 Research Special Interest Group.

Multiple animal species and approaches have been used for modeling different aspects of burn care, with some strategies considered more appropriate or translatable than others. On April 15, 2021, the Research Special Interest Group of the American Burn Association held a virtual session as part of the agenda for the annual meeting. The session was set up as a pro/con debate on the use of small versus large animals for application to four important aspects of burn pathophysiology: burn healing/conversion, scarring, inhalation injury, and sepsis. For each of these topics, two experienced investigators (one each for small and large animal models) described the advantages and disadvantages of using these preclinical models. The use of swine as a large animal model was a common theme due to anatomic similarities with human skin. The exception to this was a well-defined ovine model of inhalation injury; both of these species have larger airways which allow for incorporation of clinical tools such as bronchoscopes. However, these models are expensive and demanding from labor and resource standpoints. Various strategies have been implemented to make the more inexpensive rodent models appropriate for answering specific questions of interest in burns. Moreover, modeling burn-sepsis in large animals has proven difficult. It was agreed that the use of both small and large animal models has merit for answering basic questions about the responses to burn injury. Expert opinion and the ensuing lively conversations are summarized herein, which we hope will help inform experimental design of future research.

The Biology of Extracellular Matrix Proteins in Hypertrophic Scarring.

Significance: Hypertrophic scars (HTS) are a fibroproliferative disorder that occur following deep dermal injury and affect up to 72% of burn patients. These scars result in discomfort, impaired mobility, disruption of normal function and cosmesis, and significant psychological distress. Currently, there are no satisfactory methods to treat or prevent HTS, as the cellular and molecular mechanisms are complex and incompletely understood. This review summarizes the biology of proteins in the dermal extracellular matrix (ECM), which are involved in wound healing and hypertrophic scarring. Recent Advances: New basic research continues toward understanding the diversity of cellular and molecular mechanisms of normal wound healing and hypertrophic scarring. Broadening the understanding of these mechanisms creates insight into novel methods for preventing and treating HTS. Critical Issues: Although there is an abundance of research conducted on collagen in the ECM and its relationship to HTS, there is a significant gap in understanding the role of proteoglycans and their specific isoforms in dermal fibrosis. Future Directions: Exploring the biological roles of ECM proteins and their unique isoforms in HTS, mature scars, and normal skin will further the understanding of abnormal wound healing and create a more robust understanding of what constitutes dermal fibrosis. Research into the biological roles of ECM protein isoforms and their regulation during wound healing warrants a more extensive investigation to identify their distinct biological functions in cellular processes and outcomes.

Molecular Features of Hypertrophic Scars After Thermal Injury: Is There a Biologic Basis for Laser Therapy?

Significance: Hypertrophic scars (HTS) and keloids are common after thermal injuries and other trauma to deep regions of dermis of the skin. These abnormal scars can cause contractures and the thick masses of scar tissue that result in functional and cosmetic impairment. Management of these dermal fibrotic conditions includes a wide range of medical and surgical treatments, which can be time consuming, only partially effective, and often uncomfortable for patients. Recent Advances: The molecular pathophysiology of HTS has become more understood over the past two decades, where thermal injury to the reticular dermis results in an inflammatory response, fibrogenic growth factor release, and the formation of a dermal scar with increased collagen and proteoglycan composition in an abnormal morphology. Lasers are becoming a widely used form of treatment for these types of scars; however, the evidence for the beneficial effects of laser treatments and the understanding of their mechanism of action are still evolving. Critical Issues: Paradoxically, laser delivery of thermal energy to the skin is suggested to improve scar remodeling and wound healing, yet HTS is a well-recognized complication of excessive thermal energy delivered by laser treatments. This review aims to examine the current evidence for the use of lasers for HTS, and to investigate the molecular mechanisms where re-injury of a burn scar from laser treatment could result in overall improvements in scar quality. Future Directions: Improved design of clinical trials for the treatment of scarring in the future will evolve from new methodology and models of HTS in animals and humans.

Fluorescent light energy modulates healing in skin grafted mouse model.

Skin grafting is often the only treatment for skin trauma when large areas of tissue are affected. This surgical intervention damages the deeper dermal layers of the skin with implications for wound healing and a risk of scar development. Photobiomodulation (PBM) therapy modulates biological processes in different tissues, with a positive effect on many cell types and pathways essential for wound healing. This study investigated the effect of fluorescent light energy (FLE) therapy, a novel type of PBM, on healing after skin grafting in a dermal fibrotic mouse model. Split-thickness human skin grafts were transplanted onto full-thickness excisional wounds on nude mice. Treated wounds were monitored, and excised xenografts were examined to assess healing and pathophysiological processes essential for developing chronic wounds or scarring. Results demonstrated that FLE treatment initially accelerated re-epithelialization and rete ridge formation, while later reduced neovascularization, collagen deposition, myofibroblast and mast cell accumulation, and connective tissue growth factor expression. While there was no visible difference in gross morphology, we found that FLE treatment promoted a balanced collagen remodeling. Collectively, these findings suggest that FLE has a conceivable effect at balancing healing after skin grafting, which reduces the risk of infections, chronic wound development, and fibrotic scarring.

Stimulation of toll-like receptor pathways by burn eschar tissue as a possible mechanism for hypertrophic scarring.

Hypertrophic scars (HTS) are a common complication following burn injuries with prolonged inflammation. They do not respond well to current treatment options including mechanical, biomolecular and surgical therapies. Toll-like receptor (TLR) 2 and 4 respond to microbes and damaged endogenous ligands to trigger pro-inflammatory pathways, and they are expressed more in HTS fibroblasts compared to normal skin fibroblasts. TLR2 responds to microbial lipoteichoic acid (LTA) while TLR4 responds to microbial lipopolysaccharide (LPS) and endogenous ligands. We investigated the role of burn tissue and small leucine-rich proteoglycans (decorin and biglycan) in the stimulation of TLR2 and TLR4 pathways using cells stably transfected with TLR2 or TLR4 linked to a reporter system. Normal skin (n = 5) was collected post-abdominoplasty, and burn eschar samples (n = 18) were collected from 18 patients between 0 and 14 days post-burn. We found that burn tissue stimulates TLR2 activity significantly more than normal tissue and contains significantly higher levels of LTA. Burn tissue was a stronger stimulator of TLR4 than was normal skin. Burn tissue samples' stimulation of TLR4 and TLR2 correlated. The time post-burn (0-14 days) of wound tissue sampling correlated positively but moderately with TLR2 and TLR4 simulation. In comparison to the dose-dependent effects of natural decorin or biglycan on TLR4 activation, their denatured forms exhibited stronger or weaker stimulation, respectively. They were not potent stimulators of TLR2. TLR2 and TLR4 stimulation is not limited to bacteria in wounds and likely involves multiple endogenous damage-associated molecular patterns. Insight into mechanisms of HTS will facilitate the development of future targeted therapies to modify wound progression and provide benefits to patients suffering with HTS and other fibroproliferative disorders.

Engineered Skin Substitute Regenerates the Skin with Hair Follicle Formation.

Currently, engineered skin substitutes (ESS) are unable to regenerate cutaneous appendages. Recent studies have shown that skin-derived precursors (SKPs), which are extensively available, have the potential to induce hair follicle neogenesis. Here, we demonstrate that ESS consisting of culture-expanded SKPs and epidermal stem cells (Epi-SCs) reconstitute the skin with hair follicle regeneration after grafting into nude mice. SKPs seeded in a C-GAG matrix proliferated and expressed higher levels of hair induction signature genes-such as Akp2, Sox2, CD133 and Bmp6-compared to dermal fibroblasts. Moreover, when ESS prepared by seeding a mixture of culture-expanded murine SKPs and human adult Epi-SCs into a C-GAG matrix was grafted into full-thickness skin wounds in nude mice, black hairs were generated within 3 weeks. Immunofluorescence analysis showed that the SKPs were localized to the dermal papillae of the newly-formed hair follicle. Our results indicate that SKPs can serve as the hair-inductive cells in ESS to furnish it with hair genesis potential.

Orbital Compartment Syndrome Following Major Burn Resuscitation: A Case Series and Survey of Practice Patterns.

Orbital compartment syndrome (OCS) is a rare but devastating complication of over-resuscitation in burn patients that may lead to permanent visual loss. The purpose of this study was to 1) present a series of burn patients with OCS and 2) survey practice patterns of monitoring intra-ocular pressure (IOP) during burn resuscitation. Cases of OCS at two American Burn Association (ABA)-verified burn centers were retrospectively reviewed. Patients were included if they 1) required lateral canthotomy/cantholysis for elevated IOPs or 2) developed blindness on admission unrelated to any other ocular pathology. Data were collected on demographics, burn characteristics, fluid administration, ophthalmologic findings, and complications. An eight-item electronic survey was distributed by email through the ABA to all physician members. Twelve patients with OCS were identified, with a mean age of 47.8 ± 12.4 years and TBSA of 63.7 ± 18.6%. Mean fluid resuscitation at 24 hours was 4.9 ± 1.6 ml/kg/%TBSA or 0.29 ± 0.06 liter/kg. Eight patients underwent canthotomy/cantholysis for OCS, whereas four were later found to have visual loss. A total of 83 (14%) ABA physicians responded to the survey. IOP was routinely measured by 23% of respondents during acute burn resuscitation. OCS appears to have developed despite a relatively low 24-hour ml/kg/% burn resuscitation volume, but with a relatively higher cumulative (liter/kg) fluid volume. Their survey found that monitoring of IOP during burn resuscitation is not routinely performed by the majority of providers. Taken together, the present study suggests clinical guidelines to recognize this complication of over-resuscitation.

A Preliminary Report of the Biochemical and Clinical Effects of 1,4-Diaminobutane on Prevention of Human Hypertrophic Scars.

Objective evidence for the role of inhibition of collagen cross-linking in human scar using a nontoxic topical inhibitor, 1,4-diaminobutane (1,4 DAB), in patients with scars at risk for hypertrophic scar formation is presented. The authors used a concentration of 1,4 DAB of 0.8% (weight/volume) in a cream base similar to Glaxal Base. Application was once per day at night. The control was treated with cream base alone. In treatment phase studies at 2 months, tissue biopsies were performed and used to determine a therapeutic effect biochemically in paired scars harvested chosen with typical hypertrophic scars at two major treatment centers. Tissue transglutaminase activity revealed a significant reduction of the ε-(γ-glutamyl)lysine cross-links in the treated scars: 7.96 ± 1.51 pmol/µmol amino acid versus 14.78 ± 3.52 pmol/µmol amino acid. A subset of paired scars (n = 15) was also analyzed for soluble procollagen type III amino propeptide. The effect was a significant increase in procollagen type III amino propeptide in the scars treated with 1,4 DAB compared with sham-treated scars: 47.75 ± 4.6 µg/mg wet weight versus 39.08 ± 6.02 µg/mg wet weight, respectively. Levels of tissue 1,4 DAB was found to be twice as high in the presence of the active cream versus in the tissue of the control group. In subsequent prophylaxis studies, the authors treated 44 breast reduction patients prospectively with active cream to one or the other side in a double-blind randomized fashion. Hardness (in grams) measured using a Rex Durometer at 6 and 12 weeks postoperatively along with photographs were analyzed. The mean value ± SD of 24.98 ± 1.2 g on the active side versus 31.76 ± 1.1 g on the sham side was significantly different (p < 0.05). The patient scale scores of the Patient and Observer Scar Assessment Scale were also requested by survey in a responding 27-patient subgroup at a minimum 1 year postoperatively, and the differences between the two sides were found to be statistically significant, where the mean on the active side was 14.07 ± 1.34 and the mean on the sham side was 21.41 ± 1 (p < 0.05). The results are evidence to support the use of this agent in prevention of hypertrophic scars. CLINICAL QUESTION/LEVEL OF EVIDENCE:: Therapeutic, II.

Advanced Training and Job Satisfaction Among Recent Canadian Plastic Surgery Graduates.

BACKGROUND: In order to increase one's competitiveness in the current job market, Canadian plastic surgery graduates may complete additional degrees and multiple fellowships. The authors sought to determine the impact of this additional training on the practice profile of recent graduates and determine the current state of job satisfaction among this group. METHODS: An anonymous cross-sectional online survey was created and sent to all 250 graduates of Canadian plastic surgery residencies from 2005 to 2015. Demographics were collected and questions grouped into clinical, teaching, research, and administrative components. Questions pertaining to job satisfaction were also included. RESULTS: The response rate to the survey was 39%. Sixty-nine (71%) respondents had permanent attending positions at the time of survey completion, while the remaining 28 respondents did not. Among those with permanent positions, 59 (86%) completed at least one fellowship and 30 (43%) have an advanced degree. Of those who did fellowship training, 76% practice primarily in their area of subspecialty. Having an advanced degree showed a trend to a higher percentage of practice dedicated to research (5.6% vs 1.9%; P = .074) and more publications per year were seen among this group (1.31 vs 0.30; P = .028). Eighty-six percent of respondents are satisfied with their current attending position. CONCLUSIONS: The majority of recent Canadian plastic surgery graduates are undergoing fellowship training and are practicing primarily in their fields of subspecialty training. Having a postgraduate degree was associated with a higher number of publications per year as an attending surgeon. Job satisfaction is high among recent graduates.

HISTORIQUE: Afin d'accroître leur compétitivité sur le marché du travail, les diplômés canadiens en chirurgie plastique peuvent obtenir d'autres diplômes et de multiples postdoctorats. Les auteurs ont cherché à établir les retombées de cette formation supplémentaire sur le profil de pratique des récents diplômés ainsi que la satisfaction au travail des membres de ce groupe. MÉTHODOLOGIE: Les 250 diplômés d'une résidence en chirurgie plastique au Canada entre 2005 et 2015 ont reçu un sondage transversal anonyme en ligne. Les chercheurs ont recueilli les données démographiques et ont regroupé les questions dans les volets de la clinique, de l'enseignement, de la recherche et de l'administration. Il y avait également des questions sur la satisfaction au travail. RÉSULTATS: Le taux de réponse au sondage s'élevait à 39 %. Soixante-neuf répondants (71 %) occupaient un poste permanent au moment du sondage, contrairement aux 28 autres. Chez ceux qui occupaient un poste permanent, 59 (86 %) avaient effectué au moins un postdoctorat et 30 (43 %) possédaient un diplôme avancé. Parmi ceux qui avaient fait un postdoctorat, 76 % exerçaient surtout dans leur domaine de surspécialité. Un diplôme avancé s'associait à une tendance vers un pourcentage plus élevé de pratiques vouées à la recherche (5.6 % par rapport à 1.9 %; P = .074), qui suscitaient plus de publications annuelles (1.31 par rapport à 0.30; P = .028). Quatre-vingt-six pour cent des répondants étaient satisfaits de leur poste. CONCLUSIONS: La majorité des récents diplômés en chirurgie plastique au Canada étudient au postdoctorat et exercent surtout dans leur domaine de surspécialité. Le postdoctorat s'associait à un plus grand nombre de publications par année de la part des chirurgiens. La satisfaction au travail était élevée chez les récents diplômés.

Inhalation Injury Does Not Influence the Amount of Blood Transfused to Major Burn Patients: A Secondary Analysis from the Transfusion Requirement in Burn Care Evaluation Study.

Patients with major burn injuries typically require numerous blood transfusions. It is not known if an inhalation injury (INHI) directly influences the need for blood transfusion. The purpose of this study was to determine whether INHI increases the amount of blood transfused to major burn patients. A secondary analysis from the Transfusion Requirement in Burn Care Evaluation (TRIBE) study was conducted. Patients with INHI were compared with patients without INHI. The number of red blood cell (RBC) transfusions per day (RBC per day) between INHI and No INHI was analyzed with a multivariable regression. Patients with INHI (n = 78) had significantly larger burns (P = .0004), larger full-thickness burns (P = .0007), greater admission APACHE score (P < .0001), higher admission multiple organ dysfunction scores (P < .0001), and were transfused more RBC per day (P = .009) than No INHI patients (n = 267). In the multivariable regression analysis, RBC per day was significantly associated with the %TBSA burn (P < .0001), age of the patient (P = .004), the need for more than 1 day of mechanical ventilation (P < .0001), the occurrence of at least one blood stream infection (BSI; P = .044), and being assigned to the liberal transfusion arm of TRIBE (P < .001) but not the presence of INHI (P = .056). The null hypothesis that INHI exerts no influence on the amount of blood transfused could not be rejected. Larger burn size, advanced patient age, mechanical ventilation, and BSIs are important determinants of the blood transfusion rate in major burn patients.

The Effects of Storage Age of Blood in Massively Transfused Burn Patients: A Secondary Analysis of the Randomized Transfusion Requirement in Burn Care Evaluation Study.

OBJECTIVES: Major trials examining storage age of blood transfused to critically ill patients administered relatively few blood transfusions. We sought to determine if the storage age of blood affects outcomes when very large amounts of blood are transfused. DESIGN: A secondary analysis of the multicenter randomized Transfusion Requirement in Burn Care Evaluation study which compared restrictive and liberal transfusion strategies. SETTING: Eighteen tertiary-care burn centers. PATIENTS: Transfusion Requirement in Burn Care Evaluation evaluated 345 adults with burns greater than or equal to 20% of the body surface area. We included only the 303 patients that received blood transfusions. INTERVENTIONS: The storage ages of all transfused red cell units were collected during Transfusion Requirement in Burn Care Evaluation. A priori measures of storage age were the the mean storage age of all transfused blood and the proportion of all transfused blood considered very old (stored ≥ 35 d). MEASUREMENTS AND MAIN RESULTS: The primary outcome was the severity of multiple organ dysfunction. Secondary outcomes included time to wound healing, the duration of mechanical ventilation, and in-hospital mortality. There were 6,786 red cell transfusions with a mean (± SD) storage age of 25.6 ± 10.2 days. Participants received a mean of 23.4 ± 31.2 blood transfusions (range, 1-219) and a mean of 5.3 ± 10.7 units of very old blood. Neither mean storage age nor proportion of very old blood had any influence on multiple organ dysfunction severity, time to wound healing, or mortality. Duration of ventilation was significantly predicted by both mean blood storage age and the proportion of very old blood, but this was of questionable clinical relevance given extreme variability in duration of ventilation (adjusted r ≤ 0.01). CONCLUSIONS: Despite massive blood transfusion, including very old blood, the duration of red cell storage did not influence outcome in burn patients. Provision of the oldest blood first by Blood Banks is rational, even for massive transfusion.

Platelet-derived growth factor receptor beta identifies mesenchymal stem cells with enhanced engraftment to tissue injury and pro-angiogenic property.

Mesenchymal stem cells (MSCs) are heterogeneous likely consisting of subpopulations with various therapeutic potentials. Here we attempted to acquire a subset of MSCs with enhanced effect in wound healing. We found that human placental MSCs expressing platelet-derived growth factor (PDGF) receptor (PDGFR)-ß exhibited greater proliferation rates and generated more colony-forming unit-fibroblast (CFU-F), compared to PDGFR-ß- MSCs. Notably, PDGFR-ß+ MSCs expressed higher levels of pro-angiogenic factors such as Ang1, Ang2, VEGF, bFGF and PDGF. When 106 GFP-expressing MSCs were topically applied into excisional wounds in mice, PDGFR-ß+ MSCs actively incorporated into the wound tissue, resulting in enhanced engraftment (3.92 ± 0.31 × 105 remained in wound by 7 days) and accelerated wound closure; meanwhile, PDGFR-ß- MSCs tended to remain on the top of the wound bed with significantly fewer cells (2.46 ± 0.26 × 105) engrafted into the wound, suggesting enhanced chemotactic migration and engraftment of PDGFR-ß+ MSCs into the wound. Real-Time PCR and immunostain analyses revealed that the expression of PDGF-B was upregulated after wounding; transwell migration assay showed that PDGFR-ß+ MSCs migrated eightfold more than PDGFR-ß- MSCs toward PDGF-BB. Intriguingly, PDGFR-ß+ MSC-treated wounds showed significantly enhanced angiogenesis compared to PDGFR-ß- MSC- or vehicle-treated wounds. Thus, our results indicate that PDGFR-ß identifies a subset of MSCs with enhanced chemotactic migration to wound injury and effect in promoting angiogenesis and wound healing, implying a greater therapeutic potential for certain diseases.

Ivy Loop Wiring: A Useful Form of Endotracheal Tube Stabilization in Burn Patients.

The stabilization of endotracheal tubes in the burn population presents many problems. Access to the face for dressings, debridements, and the use of topical antimicrobials prevent adequate stabilization of the endotracheal tube with commonly used methods. Conventional methods have an increased risk of shifting, which can lead to injury to the friable burned tissue or unplanned extubation. To prevent these complications, alternative methods using the dentition to stabilize the endotracheal tube have been described. Here, we present our technique of using Ivy loops to secure the endotracheal tube. It is a simple method with low complications that provides a strong stabilization of the tube while giving access to the face.

La stabilisation de la sonde trachéale au sein de la population des grands brûlés s'associe à de nombreux problèmes. Il est impossible d'utiliser les méthodes habituelles pour la stabiliser, afin de conserver l'accès au visage pour les pansements, les débridements et l'application d'antimicrobiens topiques. La méthode classique accroît le risque de délogement, qui peut susciter des blessures aux tissus brûlés friables et une extubation non planifiée. Afin de prévenir ces complications, il existe une autre méthode de stabilisation de la sonde trachéale, qui fait appel à la dentition. Dans la présente étude, les chercheurs exposent leur technique d'utilisation des ligatures d'Ivy pour sécuriser la sonde trachéale. C'est une méthode simple, au faible taux de complications, qui assure une stabilisation élevée de la sonde tout en maintenant l'accès au visage.

Distinctively Expressed Cytokines by Three Different Inflammation Cells and Their Interaction with Keratinocytes in Wound Healing.

Inflammatory cells exert crucial influence on wound healing, while exploration is still desired to get further insight into the key factors that promote the process. In the present study, we performed comparative microarray data analysis of the three types of inflammatory cells isolated from skin wounds and focused on differentially expressed secreted factors. Gene Ontology enrichment and receptor analysis indicated that 11 genes of secreted factors in Ly6C+ inflammatory macrophages and 27 genes of secreted factors in neutrophils exhibited higher (≥ 5-fold) expression, and all these factors were considered as candidates with potentially important role in keratinocyte activation. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis revealed that TNF and IL17 signaling pathways were activated by Ly6C+ inflammatory macrophages secreted cytokines, while TGF-beta, HIF-1, NF-κB, and Rap 1 signaling pathways and pathways regulating pluripotency of stem cells were highly involved with neutrophils secreted cytokines. Taking TNF as an example, the source of the cytokine and its impact on keratinocytes were verified by immunofluorescence, gene knockout mice, and quantitative phosphoproteomics. Collectively, this study has indicated distinctively expressed cytokines in three inflammatory cells, which is helpful in identifying key factors in inducing keratinocyte signaling and in wound healing.