Special problems in burns

Efficacy of stromal vascular fraction and enzyme-free mechanical isolation therapy in experimental full thickness burn wounds

BACKGROUND

Autologous cell suspensions obtained by a stromal vascular fraction (SVF) and enzyme-free mechanical isolation (EMI) are an alternative in the treatment of burn wounds. In this study, we aimed to investigate the effect of autologous cell suspensions obtained by SVF and EMI on full-thickness skin burn wounds.

METHODS

A total of 45 male Sprague-Dawley rats were divided into three groups, SVF group, EMI group, and SVF + EMI group. The groups were also classified as the first, second, and third week of the burn to reveal the effect of the treatment on the burn in the early, middle, and late stages. For treatment, 0.2 ml SVF or 0.2 ml EMI was injected subcutaneously into the burn lesions of the subjects. Histopathological examination was performed on the burn wounds taken at the end of the experiment, and Ki67, CD44, CD73, CD90, and CK17 expressions were evaluated.

RESULTS

Histological examination revealed that there was no improvement in the control samples, but the skin was multicellular, vascularization was present. Histologic scores in all groups was significantly better than control, and SVF + EMI was the best group in terms of recovery (p < 0.05). Ki67, CK17, CD44, CD73, and CD90 expressions were significantly higher in the treatment groups compared to the control (p < 0.05).

CONCLUSION

We found in our study that both applications significantly increased the healing of the burn wound. Moreover, SVF + EMI application provided more improvement than SVF or EMI alone.

Surgical Repair of the Acute Burn Wound: Who, When, What Techniques? What Is the Future?

Modern burns surgery is multidisciplinary, multimodal and includes a dermal preservation approach. The management of the surgical wound starts in the pre-hospital environment with stabilization and assessment of the burn injured patient according to protocols of trauma resuscitation with special emphasis in the assessment of the burn depth and surface area. A large burn requires fluid resuscitation and physiological support, including counterbalancing hyper metabolism, fighting infection and starting a long burns intensive care journey. A deep burn may impose the need for surgical debridement and cover through a staged approach of excision of devitalized tissue depending on its extension and patient circumstances. These methodologies warrant patients survivability and require professionals integrated in a multidisciplinary team sharing decisions and directing management. Burns Multimodality involves multiple techniques used according to patient's needs, wound environment, operators experience and available resources. Traditional practices used together with new techniques may reduce morbidity and operative time but also challenge stablished practice. The concept of using the best teams with the best techniques combines with the need for selective and judicious surgery that preserves tissue architecture and spares as much as possible dermal component, therefore reducing the possibility of functional impairment and cosmetic embarrassment caused by pathological scars. Who is best placed to perform these tasks, the appropriate or best timing of surgery and the different practices used to achieve best results will be discussed, together with a reflection on what the future holds for these fundamental steps in the management of the burn injured patient turning into a functional burn survivor.

Prise en charge des brûlures en préhospitalier et aux urgences

Une brûlure est une lésion de la peau ou d’un autre tissu organique principalement causée par la chaleur ou les rayonnements, la radioactivité, l’électricité, la friction ou le contact avec des produits chimiques. Les plus fréquentes, les brûlures thermiques (dues à la chaleur), surviennent lorsque certaines cellules ou toutes les cellules de la peau ou d’autres tissus sont détruites par des liquides bouillants, des solides chauds (brûlures de contact), ou des flammes. En France, l’incidence des brûlures prises en charge à l’hôpital est environ de 13 pour 100 000 habitants. La prise en charge en urgence du brûlé grave par lésion thermique est bien décrite, une recommandation de pratique professionnelle a été publiée en 2019 par la Société française d’anesthésie et de réanimation, en association avec la Société francophone de brûlologie, la Société française de médecine d’urgence et l’Association des anesthésistes-réanimateurs pédiatriques d’expression française. Pourtant, l’urgentiste va être confronté à de nombreuses brûlures de gravité et de nature différentes. Nous faisons ici une mise au point sur les données connues en termes d’épidémiologie, de manifestations cliniques et des différentes thérapeutiques qui peuvent être proposées dans la prise en charge des brûlures. Nous faisons aussi le point sur les localisations à risque particulier que l’urgentiste doit connaître, ainsi que sur les intoxications qui peuvent être associées aux brûlures. Nous détaillons aussi certains contaminants qui sont à connaître.

Monophosphoryl Lipid a Attenuates Multiorgan Dysfunction During Post-Burn Pseudomonas Aeruginosa Pneumonia in Sheep

BACKGROUND

Monophosphoryl lipid A (MPLA) is a TLR4 agonist that has potent immunomodulatory properties and modulates innate immune function to improve host resistance to infection with common nosocomial pathogens in mice. The goal of this study was to assess the safety and efficacy of MPLA in a sheep model of burn injury and Pseudomonas aeruginosa pneumonia. The sheep provides a favorable model for preclinical testing as their response to TLR4 agonists closely mimics that of humans.

METHODS

Twelve chronically instrumented adult female Merino sheep received 20% total body surface area, third-degree cutaneous burn under anesthesia and analgesia. At 24 h after burn, sheep were randomly allocated to receive: MPLA (2.5 μg/kg i.v., n = 6), or vehicle (i.v., n = 6). At 24 h after MPLA or vehicle treatment, Pseudomonas aeruginosa pneumonia was induced. Sheep were mechanically ventilated, fluid resuscitated and cardiopulmonary variables were monitored for 24 h after induction of pneumonia. Cytokine production, vascular barrier function, and lung bacterial burden were also measured.

RESULTS

MPLA infusion induced small and transient alterations in core body temperature, heart rate, pulmonary artery pressure, and pulmonary vascular resistance. Pulmonary mechanics were not altered. Vehicle-treated sheep developed severe acute lung injury during Pseudomonas aeruginosa pneumonia, which was attenuated by MPLA as indicated by improved PaO2/FiO2 ratio, oxygenation index, and shunt fraction. Sheep treated with MPLA also exhibited less vascular leak, lower blood lactate levels, and lower modified organ injury score. MPLA treatment attenuated systemic cytokine production and decreased lung bacterial burden.

CONCLUSIONS

MPLA was well tolerated in burned sheep and attenuated development of acute lung injury, lactatemia, cytokinemia, vascular leak, and hemodynamic changes caused by Pseudomonas aeruginosa pneumonia.

Photobiomodulation associated to cellular therapy improve wound healing of experimental full thickness burn wounds in rats

Adipose derived stromal vascular fraction (SVF) is a method of cell therapy potentially applicable for treatment of full thickness burns. Here we investigated if the association of photobiomodulation (PBM) with SVF therapy could improve wound healing in experimentally induced full thickness burn wounds in rats compared to the topical agent 2% silver sulfadiazine in a dose-dependent manner. Sixty-six male Wistar rats were divided in 4 groups containing 5 animals each which received the following treatments: 2% sulfadiazine (SD), SVF, SVF plus PBM at 30 mW (SVFL30), and SVF plus PBM at 100 mW (SVFL100). Two donor animals were used for each experimental series with 3, 7 and 30 days. Digital photography, microscopic analysis with Hematoxilin and Eosin (H&E), quantification of collagen type I by picrosirius red staining analysis and wound contraction evaluation were performed in order to quantify the results. At day 3 SVF alone or combined with PBM promoted increased early inflammatory response compared to SD. At day 7 SVFL30 and SVFL100 enhanced inflammatory cells infiltration, angiogenesis and fibroblast content compared to SVF and SD groups. At day 30 collagen concentration and wound contraction were higher in SVFL30 when compared to the other groups. In conclusion PBM promotes a synergistic outcome with SVF therapy with a dose dependent effect potentializing wound healing of experimental full thickness burns in rats through amplification of early inflammatory response, enhanced angiogenesis, fibroblast content, accentuated wound contraction and collagen concentration.

Extracellular vesicles derived from mesenchymal cells: perspective treatment for cutaneous wound healing in pediatrics

AIM

We evaluated the effects of the intradermal injection of extracellular vesicles (EVs) derived from adipose stem cells (ASC-EVs) and bone marrow cells (BM-EVs) in an experimental cutaneous wound repair model.

METHODS

Mesenchymal stem cells (MSCs) were in vitro expanded from adipose (ASC) or BM tissues (BM-MSC) of rabbits. EVs were separated from the supernatants of confluent ASC and BM-MSCs. Two skin wounds were induced in each animal and treated with MSC or EV injections. Histological examination was performed postinoculation.

RESULTS

EV-treated wounds exhibited a better restoration compared with the counterpart MSC treatment. ASC-EV-treated wounds were significantly better than BM-EVs (p = 0.036).

CONCLUSION

EV topical inoculation provides restored architecture during cutaneous wound healing and represents a promising solution for regenerative medicine in children.

Burns in Children

Children have a great deal to gain from recent and future advances in burn care. A very broad range of realized and potential developments are involved. These will be very briefly reviewed within the context of four areas: 1) early evaluation and care issues, 2) acute surgical and critical care issues, 3) rehabilitation and reconstruction issues, and 4) organizational and outcomes issues.

Adipose tissue stromal vascular fraction in the treatment of full thickness burns in rats

PURPOSE:

To analyze the healing effects of stromal vascular fraction (SVF) application compared to wound dressing with 2% silver sulfadiazine in full thickness burn wounds in rats.

METHODS:

Animals were divided into two groups: 2% silver sulfadiazine group and SVF group. Both groups received occlusive bandages while the first one was treated with 2% silver sulfadiazine and the latter was treated with injections of SVF prepared from adipose tissue extracted from an animal donor. The animals were accompanied through 3, 7 and 30 days for evaluation of macroscopic, microscopic and morphometric aspects.

RESULTS:

On day three, a significant increase (p<0.05) of infiltration of polymorphonuclear, fibrin formation and fibroblasts migration in SVF group was observed. On the 7th day the mononuclear infiltrate, angiogenesis, collagen and fibroblasts were significantly increased in the SVF group (p<0.05). At 30 days significantly increased collagen deposition was observed in the SVF group (p<0.05) .

CONCLUSION:

Adipose tissue derived stromal vascular fraction injections promotes better wound repair than 2% silver sulfadiazine in the treatment of full thickness burn in rats during the evaluated experimental period.

Mesenchymal stromal cells for cutaneous wound healing in a rabbit model: pre-clinical study applicable in the pediatric surgical setting

Objective

Mesenchymal stromal cells (MSCs) expanded in vitro have been proposed as a potential therapy for congenital or acquired skin defects in pediatrics. The aim of this pre-clinical study was to investigate the effects of intradermal injections of MSC in experimental cutaneous wound repair comparing allogeneic and autologous adipose stem cells (ASCs) and autologous bone marrow-mesenchymal stromal cells (BM-MSCs).

Methods

Mesenchymal stromal cells were in vitro expanded from adipose and BM tissues of young female New Zealand rabbits. MSCs were characterized for plastic adhesion, surface markers, proliferation and differentiation capacity. When an adequate number of cells (ASCs 10 × 10⁶ and BM-MSCs 3 × 10⁶, because of their low rate of proliferation) was reached, two skin wounds were surgically induced in each animal. The first was topically treated with cell infusions, the second was used as a control. The intradermal inoculation included autologous or allogeneic ASCs or autologous BM-MSCs. For histological examination, animals were sacrificed and wounds were harvested after 11 and 21 days of treatment.

Results

Rabbit ASCs were isolated and expanded in vitro with relative abundance, cells expressed typical surface markers (CD49e, CD90 and CD29). Topically, ASC inoculation provided more rapid wound healing than BM-MSCs and controls. Improved re-epithelization, reduced inflammatory infiltration and increased collagen deposition were observed in biopsies from wounds treated with ASCs, with the best result in the autologous setting. ASCs also improved restoration of skin architecture during wound healing.

Conclusion

The use of ASCs may offer a promising solution to treat extended wounds. Pre-clinical studies are however necessary to validate the best skin regeneration technique, which could be used in pediatric surgical translational research.

Blast injury: impact on brain and internal organs

Blast trauma can kill or injure by multiple different mechanisms, not all of which may be obvious on initial presentation. Patients injured by blast effects should be treated as having multisystem trauma and managed according to Advanced Trauma Life Support guidelines. For the most severely injured patients, damage control resuscitation should be practiced until definitive hemorrhage control has been achieved. Patients with blast injuries may present in mass-casualty episodes that can overwhelm local resources. This article reviews some specific injuries, as well as the importance of mild traumatic brain injury. The importance of rehabilitation is discussed.