Eric Bey

New approach to radiation burn treatment by dosimetry-guided surgery combined with autologous mesenchymal stem cell therapy

The therapeutic management of severe radiation burns remains a challenging issue. Conventional surgical treatment (excision and skin autograft or rotation flap) often fails to prevent unpredictable and uncontrolled extension of the radiation necrotic process. We report here an innovative therapeutic strategy applied to the victim of a radiation accident (December 15, 2005) with an iridium gammagraphy radioactive source (192Ir, 3.3 TBq). The approach combined numerical dosimetry-guided surgery with cellular therapy using mesenchymal stem cells. A very severe buttock radiation burn (2000 Gy at the center of the skin surface lesion) of a 27-year-old Chilean victim was widely excised (10 cm in diameter) using a physical and anatomical dose reconstruction in order to better define the limit of the surgical excision in apparently healthy tissues. A secondary extension of the radiation necrosis led to a new excision of fibronecrotic tissues associated with a local cellular therapy using autologous expanded mesenchymal stem cells as a source of trophic factors to promote tissue regeneration. Bone marrow-derived mesenchymal stem cells were expanded according to a clinical-grade technique using closed culture devices and serum-free medium enriched in human platelet lysate. The clinical evolution (radiation pain and healing progression) was favorable and no recurrence of radiation inflammatory waves was observed during the 11 month patients follow-up. This novel multidisciplinary therapeutic approach combining physical techniques, surgical procedures and cellular therapy with adult stem cells may be of clinical relevance for improving the medical management of severe localized irradiations. It may open new prospects in the field of radiotherapy complications.

Emerging therapy for improving wound repair of severe radiation burns using local bone marrow‐derived stem cell administrations

The therapeutic management of severe radiation burns remains a challenging issue today. Conventional surgical treatment including excision, skin autograft, or flap often fails to prevent unpredictable and uncontrolled extension of the radiation‐induced necrotic process. In a recent very severe accidental radiation burn, we demonstrated the efficiency of a new therapeutic approach combining surgery and local cellular therapy using autologous mesenchymal stem cells (MSC), and we confirmed the crucial place of the dose assessment in this medical management. The patient presented a very significant radiation lesion located on the arm, which was first treated by several surgical procedures: iterative excisions, skin graft, latissimus muscle dorsi flap, and forearm radial flap. This conventional surgical therapy was unfortunately inefficient, leading to the use of an innovative cell therapy strategy. Autologous MSC were obtained from three bone marrow collections and were expanded according to a clinical‐grade protocol using platelet‐derived growth factors. A total of five local MSC administrations were performed in combination with skin autograft. After iterative local MSC administrations, the clinical evolution was favorable and no recurrence of radiation inflammatory waves occurred during the patients 8‐month follow‐up. The benefit of this local cell therapy could be linked to the “drug cell” activity of MSC by modulating the radiation inflammatory processes, as suggested by the decrease in the C‐reactive protein level observed after each MSC administration. The success of this combined treatment leads to new prospects in the medical management of severe radiation burns and more widely in the improvement of wound repair.

New emerging concepts in the medical management of local radiation injury.

Treatment of severe radiation burns remains a difficult medical challenge. The response of the skin to ionizing radiation results in a range of clinical manifestations. The most severe manifestations are highly invalidating. Although several therapeutic strategies (excision, skin grafting, skin or muscle flaps) have been used with some success, none have proven entirely satisfying. The concept that stem cell injections could be used for reducing normal tissue injury has been discussed for a number of years. Mesenchymal stem cells therapy may be a promising therapeutic approach for improving radiation-induced skin and muscle damages. Pre-clinical and clinical benefit of mesenchymal stem cell injection for ulcerated skin and muscle restoration after high dose radiation exposure has been successfully demonstrated. Three first patients suffering from severe radiological syndrome were successfully treated in France based on autologous human grade mesenchymal stem cell injection combined to plastic surgery or skin graft. Stem cell therapy has to be improved to the point that hospitals can put safe, efficient, and reliable clinical protocols into practice.

Anti-HLA sensitization in extensively burned patients: extent, associated factors, and reduction in potential access to vascularized composite allotransplantation

Extensively burned patients receive iterative blood transfusions and skin allografts that often lead to HLA sensitization, and potentially impede access to vascularized composite allotransplantation (VCA). In this retrospective, single‐center study, anti‐HLA sensitization was measured by single‐antigen‐flow bead analysis in patients with deep, second‐ and third‐degree burns over ≥40% total body surface area (TBSA). Association of HLA sensitization with blood transfusions, skin allografts, and pregnancies was analyzed by bivariate analysis. The eligibility for transplantation was assessed using calculated panel reactive antibodies (cPRA). Twenty‐nine patients aged 32 ± 14 years, including 11 women, presented with a mean burned TBSA of 54 ± 11%. Fifteen patients received skin allografts, comprising those who received cryopreserved (n = 3) or glycerol‐preserved (n = 7) allografts, or both (n = 5). An average 36 ± 13 packed red blood cell (PRBC) units were transfused per patient. In sera samples collected 38 ± 13 months after the burns, all patients except one presented with anti‐HLA antibodies, of which 13 patients (45%) had complement‐fixing antibodies. Eighteen patients (62%) were considered highly sensitized (cPRA≥85%). Cryopreserved, but not glycerol‐preserved skin allografts, history of pregnancy, and number of PRBC units were associated with HLA sensitization. Extensively burned patients may become highly HLA sensitized during acute care and hence not qualify for VCA. Alternatives to skin allografts might help preserve their later access to VCA.

Alteration of the Serum N-glycome of Mice Locally Exposed to High Doses of Ionizing Radiation

Exposure of the skin to ionizing radiation leads to characteristic reactions that will often turn into a pathophysiological process called the cutaneous radiation syndrome. The study of this disorder is crucial to finding diagnostic and prognostic bioindicators of local radiation exposure or radiation effects. It is known that irradiation alters the serum proteome content and potentially post-translationally modifies serum proteins. In this study, we investigated whether localized irradiation of the skin alters the serum glycome. Two-dimensional differential in-gel electrophoresis of serum proteins from a man and from mice exposed to ionizing radiation showed that potential post-translational modification changes occurred following irradiation. Using a large-scale quantitative mass-spectrometry-based glycomic approach, we performed a global analysis of glycan structures of serum proteins from non-irradiated and locally irradiated mice exposed to high doses of γ-rays (20, 40, and 80 Gy). Non-supervised descriptive statistical analyses (principal component analysis) using quantitative glycan structure data allowed us to discriminate between uninjured/slightly injured animals and animals that developed severe lesions. Decisional statistics showed that several glycan families were down-regulated whereas others increased, and that particular structures were statistically significantly changed in the serum of locally irradiated mice. The observed increases in multiantennary N-glycans and in outer branch fucosylation and sialylation were associated with the up-regulation of genes involved in glycosylation in the liver, which is the main producer of serum proteins, and with an increase in the key proinflammatory serum cytokines IL-1β, IL-6, and TNFα, which can regulate the expression of glycosylation genes. Our results suggest for the first time a role of serum protein glycosylation in response to irradiation. These protein-associated glycan structure changes might signal radiation exposure or effects.

Reconstruction of the Achilles Tendon with a Composite Anterolateral Thigh Free Flap with Vascularized Fascia Lata: A Case Report

Reconstruction of a segmental loss of the Achilles tendon combined with defects in soft-tissue coverage creates a challenge for the surgeon. We present the case of a patient who had combined loss of the Achilles tendon and overlying soft-tissue coverage. The patient was managed successfully with a single surgical procedure involving a composite anterolateral thigh free flap with vascularized fascia lata. The functional outcome of the reconstructed ankle and morbidity in the donor thigh were evaluated at one year with use of a kinetic dynamometer combined with magnetic resonance imaging. The patient was informed that data concerning the case would be submitted for publication, and he consented. A forty-eight-year-old man sustained a complete rupture of the left Achilles tendon during military service. Primary suture repair of the tendon was performed. Four months after that operation, a new rupture occurred when the patient returned to work, and a second tendon repair was performed to reconstruct the defect with the central part of the proximal part of the Achilles tendon (the Bosworth procedure). A large hematoma formed postoperatively, followed by skin necrosis, resulting in a 12-cm segmental tendon loss with an overlying soft-tissue defect measuring 8 × 3 cm. The wound site was debrided of all fibrous and necrotic tissue (Fig. 1). Because of the lack of suitable local tissue, a composite anterolateral thigh flap with attached vascularized fascia lata was harvested after a preoperative Doppler ultrasound examination. The main cutaneous perforator was located in the middle portion of a line between the anterior superior iliac spine and the lateral edge of the patella (Fig. 2). The skin paddle of the anterolateral thigh flap (17 × 8 cm) was designed to be slightly larger than the soft-tissue defect. It was harvested along with its vascular pedicle and a portion of the fascia …

Présent et futur de la thérapie cellulaire des brûlures

Severe burned patients need definitive and efficient wound coverage. Outcome of massive burns has been improved by using cultured epithelial autografts (CEA). Despite fragility, percentages of success take, cost of treatment and long-term tendency to contracture, this surgical technique has been developed in few burn centres. First improvements were to combine CEA and dermis-like substitute. Cultured skin substitutes provide earlier skin closure and satisfying functional result. These methods have been used successfully in massive burns. Second improvement was to allow skin regeneration by using epidermal stem cells. Stem cells have capacity to differentiate into keratinocytes, to promote wound repair and to regenerate skin appendages. Human mesenchymal stem cells contribute to wound healing and were evaluated in cutaneous radiation syndrome. Skin regeneration and tissue engineering methods remain a complex challenge and offer the possibility of new treatment for injured and burned patients.

Is the deltopectoral flap born again? Role in postburn head and neck reconstruction

After extensive use for head and neck reconstruction, the deltopectoral flap has been supplanted by alternative methods of reconstruction and relegated to historical references. However, it remains a very valuable skin flap and should keep its place in the armamentarium of reconstructive surgeons for postburn head and neck reconstruction. We report here five cases of head and neck reconstruction using the deltopectoral flap: one case of perioral reconstruction after ballistic trauma, one case of nasal reconstruction after burn and three cases of neck reconstruction after burn contracture. Technical simplicity and reliability are the main features of this flap. The skin paddle is thin and pliable, and its surface can be extended after a flap delay. Previous tissue expansion can minimize donor site morbidity. The flap division necessitates a second surgical procedure. The major burn contractures of the neck are, in our opinion, an excellent indication of the deltopectoral flap.

Extensively burned patients still need blood transfusions and skin allografts: unavoidable HLA sensitization requires optimization of VCA access

Dear Sirs, We thank Gaucher and Jarraya [1] for their comments on our study [2]. This first Single Antigen Flow Bead (SAFB) analysis of the strength and breadth of human leukocyte antigen sensitization (supporting information in our study [2]) in extensively burned patients was initiated after facing reduced access to Vascularized Composite Allograft (VCA) transplants for burned candidates. We described its impact on future VCA access and addressed the sensitizing factors and their alternatives. A recent report confirmed this risks of humoral rejection of VCA on sensitized patients [3]. Transfusions are unavoidable in acute care of extensively burned patients. Blood salvage procedures despite feasible have not been widespread due to their poor efficiency/risk (major sepsis) ratio after burns [4]. Red blood cells (RBC) present some HLA molecules that remain a cause of sensitization. In Leffell et al.’s study [5] kidney transplant candidates receiving leucoreduced transfusions presented a 20% risk of HLA sensitization versus 2.4% for nontransfused patient. In our study, all burns patients excepted one (not 100% of the patients, as mentioned by Gaucher and Jarraya) were sensitized, with a relative risk to be hypersensitized 3.3 fold higher when compared to kidney transplantation candidates. This could be explained by quantitative differences in RBC transfusions; however, the amounts of RBC received by the kidney transplant candidates were unavailable, as in Leffell’s study. Skin allografts keep a role after extensive burns, provided a risk benefit ratio analysis in the light of a potential VCA indication. Burns surface under or over 70% TBSA are, respectively, led to use CPSA as overlay on skin autograft (widely meshed or micrografted) [6] or for woundbed preparation before application of cultured autologous keratinocytes (CAK) [7]. As overlay, skin xenografts offer comparable efficacy and cost to CPSA [8], while dermal matrix offers poor adherence to CAK. If Kua et al. [9] compared glycerol (GPSA) with cryopreserved (CPSA) skin allografts for full-thickness burns, it retrieved no significant difference neither for mortality rates nor for length of stay. Richters et al. [10] study reported a very low T-cell response to allogenic glycerol-treated epidermal cells. No immunogenic comparison had been reported between GPSA and CPSA; however, such clinical comparison would require extensive multicentric assessment for a limited clinical relevance. The question of the potentiation between RBC and CPSA would require an animal study. The transfusion of HLA-matched RBC is not clinically applicable due to the number of units required for the acute care. It requires the development of transfusion components lacking the expression of HLA alloantigens. Skin banks with CPSA stocks allowing for HLA-matched skin grafting are not realistic. Antibody reductions by desensitization protocols in highly sensitized kidney transplant candidates are not long lasting and frequently recur. The limited number of patients to survive such extensive burns might limit the development and validation of any HLA sensitization multiparametric score. Gaucher and Jarraya stated that HLA sensitization must be avoided to keep open the option for VCA. This should be moderated as HLA sensitization do not preclude any VCA transplantation but increase the proportion of potential transplants carrying higher risks of humoral rejection. The priority to life-saving procedures for extensive face or hand burns patients should be combined with effort to reduce their sensitization. Their access to transplants can be optimized significantly by replacing the gender-matching usually applied for VCA by a size/morphological one.

Autologous Bone Marrow Mesenchymal Stem Cells Improve the Quality and Stability of Vascularized Flap Surgery of Irradiated Skin in Pigs

Cutaneous radiation syndrome has severe long‐term health consequences. Because it causes an unpredictable course of inflammatory waves, conventional surgical treatment is ineffective and often leads to a fibronecrotic process. Data about the long‐term stability of healed wounds, with neither inflammation nor resumption of fibrosis, are lacking. In this study, we investigated the effect of injections of local autologous bone marrow‐derived mesenchymal stromal cells (BM‐MSCs), combined with plastic surgery for skin necrosis, in a large‐animal model. Three months after irradiation overexposure to the rump, minipigs were divided into three groups: one group treated by simple excision of the necrotic tissue, the second by vascularized‐flap surgery, and the third by vascularized‐flap surgery and local autologous BM‐MSC injections. Three additional injections of the BM‐MSCs were performed weekly for 3 weeks. The quality of cutaneous wound healing was examined 1 year post‐treatment. The necrotic tissue excision induced a pathologic scar characterized by myofibroblasts, excessive collagen‐1 deposits, and inadequate vascular density. The vascularized‐flap surgery alone was accompanied by inadequate production of extracellular matrix (ECM) proteins (decorin, fibronectin); the low col1/col3 ratio, associated with persistent inflammatory nodules, and the loss of vascularization both attested to continued immaturity of the ECM. BM‐MSC therapy combined with vascularized‐flap surgery provided mature wound healing characterized by a col1/col3 ratio and decorin and fibronectin expression that were all similar to that of nonirradiated skin, with no inflammation, and vascular stability. In this preclinical model, vascularized flap surgery successfully and lastingly remodeled irradiated skin only when combined with BM‐MSC therapy. Stem Cells Translational Medicine 2018:569–582