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 patient's 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.

PCC-FISH in skin fibroblasts for local dose assessment: biodosimetric analysis of a victim of the Georgian radiological accident.

We propose a new method of biodosimetry that could be applied in cases of localized irradiation. The approach is based on excess chromosome segments determination by the PCC-FISH technique in fibroblasts isolated from skin biopsy. Typically, 0 to 10 Gy ex vivo gamma-irradiated human skin biopsies were dissociated and fibroblasts were isolated and grown for several days. Cells next underwent PCC-FISH painting of whole chromosome 4, and the number of excess chromosome segments per metaphase was determined. An ex vivo reference curve correlating the number of excess chromosome segments per metaphase to the radiation dose was established and used to assess the dose delivered to the skin of one of the victims of the radiological accident that occurred at Lia in Georgia in December 2001. Specifically, the victim suffering from moist desquamation underwent skin excision in Hospital Percy (France). Measurement of excess chromosome segments per metaphase was done in fibroblasts isolated and grown from removed wounded skin and subsequent conversion to radiation doses was performed. The radiation dose map obtained was shown to be in accordance with clinical data and physical dosimetry as well as with conventional biodosimetry. These results demonstrated that PCC-FISH painting applied to skin fibroblasts may be a suitable technique for dose estimation. To assess its worth, this approach needs to be extended to future accidents involving localized radiation exposure.

Long-term regeneration of human epidermis on third degree burns transplanted with autologous cultured epithelium grown on a fibrin matrix.

BACKGROUND: Extensive third degree burn wounds can be permanently covered by the transplantation of autologous cultured keratinocytes. Many modifications to Green and colleagues' original technique have been suggested, including the use of a fibrin matrix. However, the properties of the cultured cells must be assessed using suitable criteria before a modified method of culture for therapeutic purposes is transferred to clinical use, because changes in culture conditions may reduce keratinocyte lifespan and result in the loss of the transplanted epithelium. METHODS: To evaluate the performances of human keratinocytes grown on a fibrin matrix, we assay for their colony-forming ability, their growth potential and their ability to generate an epidermis when grafted onto athymic mice. The results of these experiments allowed us to compare side by side the performance for third degree burn treatment of autologous cultured epithelium grafts grown according to Rheinwald and Green on fibrin matrices with that of grafts grown directly on plastic surfaces. RESULTS: We found that human keratinocytes cultured on a fibrin matrix had the same growth capacity and transplantability as those cultured on plastic surfaces and that the presence of a fibrin matrix greatly facilitated the preparation, handling, and surgical transplantation of the grafts, which did not need to be detached enzymatically. The rate of take of grafts grown on fibrin matrices was high, and was similar to that of conventionally cultured grafts. The grafted autologous cells are capable of generating a normal epidermis for many years and favor the regeneration of a superficial dermis. CONCLUSION: We have demonstrated that: 1) fibrin matrices have considerable advantages over plastic for the culture of skin cells for grafting and that it is now possible to generate and transplant enough cultured epithelium from a small skin biopsy to restore completely the epidermis of an adult human in 16 days; and 2) the generated epidermis self-renews itself for years. The use of fibrin matrices thus significantly improves the transplantation of cultured epithelium grafts for extensive burns as recently demonstrated in a follow-up work.

Initial general management and surgery of six extensively burned children treated with cultured epidermal autografts.

PURPOSE: The aim of this study was to document the surgical and intensive care methods used in six extensively burned children (EBC), ie, total body surface area (TBSA) burned over 70% or TBSA with deep burns over 60%, treated with cultured epidermal autografts (CEA). METHODS: Six EBC, with a mean age of 7.5 years (range, 2.5 to 12) received CEA. Their mean TBSA burned was 82% (range, 70-94) with 74% (range, 60-90) of TBSA with deep burns. All sustained flame burns and inhalation injuries. RESULTS: The survival rate was six of six. The average initial and final engraftment rates of CEA were, respectively, 79% (range, 70 to 95) and 84% (range, 72 to 100). CEA definitively covered 45% (range, 18 to 57) of TBSA for a mean cost per child of $80,000 (range, 55,000 to 110,000). CONCLUSION: Even if CEA are expensive, such engraftment rates and survival ratio results make them an excellent alternative wound covering method for EBC when donor sites for widely meshed autografts are exhausted.

Evolution and significance of circulating procalcitonin levels compared with IL-6, TNF alpha and endotoxin levels early after thermal injury.

To determine the evolution and significance of circulating procalcitonin (ProCT), IL-6 TNF alpha and endotoxin levels early after thermal injury, we performed a prospective, single unit, longitudinal study. Forty burn patients with total body surface area (TBSA) > 30 per cent were studied, of whom 33 suffered an inhalation injury. Blood samples were taken on the day of admission, every 4 h during the first day and daily during the first week. All patients had increased ProCT and IL-6 levels without any proven infection. Endotoxin and TNF alpha levels remained very low or undetectable. ProCT and IL-levels correlated well with the severity of skin burn injury (respectively, p < 0.006 and p < 0.028, using the non-parametric Kruskal-Wallis test). ProCT levels are not associated with smoke inhalation. ProCT and IL6 are prognostic factors of mortality at the time of admission but less reliable than the clinical UBS (unit burn standard) score. Endotoxin and TNF alpha were undetectable, suggesting that the problem of the early gut bacterial translocation remains to be proven.

[Inhalation burns: apropos of 198 cases. Incidence of laryngotracheal involvement]. / Les brûlures par inhalation: à propos de 198 cas incidence de l'atteinte laryngo-trachéale.

Inhalation burns and laryngotracheal involvement were studied in a retrospective series of 635 patients hospitalized for skin burns at the Center for Burn Treatment from January 1993 to January 1997. Inhalation burns were observed in 31.1% of the cases. Exclusive laryngeal involvement occurred in 19.6% of the inhalation burns. Both tracheobronchial and laryngeal burns were observed in 27.2%. Patients with inhalation burns also had facial burns (90.9%) and extensive (> 50%) or severe (UBS > 200) skin burns in 39.8% and 29.7% of the cases respectively. Mortality of skin burns was increased six-fold to 19.1% in patients who also had inhalation burns. Intubation was used alone in 60.1% and was followed by tracheotomy in 27.2%. The decision for tracheotomy was essentially based on the probable duration of ventilatory assistance. Tracheotomy was required in case of severe inhalation burns and the predictable duration of intubation was over 8 days. Laryngotracheal stenosis occurring after inhalation burns is complex and extensive, with great variability over time. Laryngotracheal calibration is indicated as first intention therapy.