Impairment of μ-calpain activation by rhTNFR:Fc reduces severe burn-induced membrane disruption in the heart

Stress cardiomyopathy is a major clinical complication after severe burn. Multiple upstream initiators have been identified; however, the downstream targets are not fully understood. This study assessed the role of the plasma membrane in this process and its relationship with the protease μ-calpain and tumor necrosis factor-alpha (TNF-α). Here, third-degree burn injury of approximately 40% of the total body surface area was established in rats. Plasma levels of LDH and cTnI and cardiac cell apoptosis increased at 0.5 h post burn, reached a peak at 6 h, and gradually declined at 24 h. This effect correlated well with not only the disruption of cytoskeletal proteins, including dystrophin and ankyrin-B, but also with the activation of μ-calpain, as indicated by the cleaved fragments of α-spectrin and membrane recruitment of the catalytic subunit CAPN1. More importantly, these alterations were diminished by blocking calpain activity with MDL28170. Burn injury markedly increased the cellular uptake of Evans blue, indicating membrane integrity disruption, and this effect was also reversed by MDL28170. Compared with those in the control group, cardiac cells in the burn plasma-treated group were more prone to damage, as indicated by a marked decrease in cell viability and increases in LDH release and apoptosis. Of note, these alterations were mitigated by CAPN1 siRNA. Moreover, after neutralizing TNF-α with rhTNFR:Fc, calpain activity was blocked, and heart function was improved. In conclusion, we identified μ-calpain as a trigger for severe burn-induced membrane disruption in the heart and provided evidence for the application of rhTNFR:Fc to inhibit calpain for cardioprotection.

Management of severe burn injuries with novel treatment techniques including maggot debridement and applications of acellular fish skin grafts and autologous skin cell suspension in a dog

CASE DESCRIPTION A 3-year-old 27-kg female spayed American Bulldog with severe burn injuries caused by a gasoline can explosion was evaluated. CLINICAL FINDINGS The dog had extensive partial- and full-thickness burns with 50% of total body surface area affected. The burns involved the dorsum extending from the tail to approximately the 10th thoracic vertebra, left pelvic limb (involving 360° burns from the hip region to the tarsus), inguinal area bilaterally, right medial aspect of the thigh, and entire perineal region. Additional burns affected the margins of the pinnae and periocular regions, with severe corneal involvement bilaterally. TREATMENT AND OUTCOME The dog was hospitalized in the hospital’s intensive care unit for 78 days. Case management involved provision of aggressive multimodal analgesia, systemic support, and a combination of novel debridement and reconstructive techniques. Debridement was facilitated by traditional surgical techniques in combination with maggot treatment. Reconstructive surgeries involved 6 staged procedures along with the use of novel treatments including applications of widespread acellular fish (cod) skin graft and autologous skin cell suspension. CLINICAL RELEVANCE The outcome for the dog of the present report highlighted the successful use of maggot treatment and applications of acellular cod skin and autologous skin cell suspension along with aggressive systemic management and long-term multimodal analgesia with debridement and wound reconstruction for management of severe burn injuries encompassing 50% of an animal’s total body surface area.

Human Umbilical Cord-Derived Mesenchymal Stem Cells Alleviate Acute Lung Injury Caused by Severe Burn via Secreting TSG-6 and Inhibiting Inflammatory Response

Objectives To investigate whether hUC-MSCs attenuated severe burn-induced ALI and the effects were based on TSG-6 secreted from hUC-MSCs. Method Rat model was established and evaluated as follows：Anires2005 animal pulmonary function tester for pulmonary function; micro-CT scanner for lung imaging manifestations; cytokine expression was measured by ELISA assay, and both inflammatory cell infiltration and lung injury were assessed by immunohistochemistry assay. Results In vitro, TSG-6 levels in serum from the burn group were significantly increased than that of the sham group. In vivo, TSG-6 levels of lung tissues and serum in the burn+ hUC-MSCs group were significantly increased than those of that in the burn group. Higher parameters of airway resistance（Ri, Re, etc）were markedly decreased, and the disordered lung texture and funicular density shadows were significantly improved after hUC-MSCs administration. Both in lung tissues and serum, increased levels of proinflammatory cytokines（TNF-α, IL-1β, IL-6）were remarkably decreased, but anti-inflammatory cytokine IL-10 increased after hUC-MSCs administration (p<0.05). These significant positive effects after hUC-MSCs transplantation did not occur in the Burn+siTSG-6 group. Conclusion Intra-tracheal implantation of hUC-MSCs has been an effective treatment for severe burn-induced ALI via promoting TSG-6 secretion and inhibiting inflammatory reaction in lung tissue.

The rise of factor X level in blood plasma of patients at severe burn injuries

This work is dedicated to the detection of imbalance between the pro- and anti-coagulant branches of hemostasis at severe burn injuries by evaluating the content or activity of individual clotting factors. To select the targets for accurate diagnostics we measured the concentrations of soluble fibrin monomeric complexes and fibrinogen, levels of total prothrombin, factor X, protein C and antithrombin III, and recorded the time of clotting in activated partial thromboplastin time and prothrombin time tests. Factor X level was increased in 26 % of patients on the first day after the burn and it rose further in 62 % patients on the 14 th day of recovery. Increasing factor X level is assumed to be a risk factor of thrombotic complications. We propose to use it as a marker of predisposition to thrombosis at severe burn injury.

Immature granulocyte percentage for prediction of sepsis in severe burn patients: a machine leaning-based approach

Background Of the existing sepsis markers, immature granulocytes (IG) most frequently reflect the presence of an infection. The importance of IG as an early predictor of sepsis and bacteremia is evaluated differently for each study. This study aimed to evaluate the effectiveness of the Sysmex XN series’ IG% as an independent prognostic indicator of sepsis using machine learning. Methods A total of 2465 IG% results from 117 severe burn patients in the intensive care unit of one institution were retrospectively analyzed. We evaluated the IG% for sepsis using the receiver operating characteristic, logistic regression, and partial dependence plot analyses. Clinical characteristics and other laboratory markers associated with sepsis, including WBC, procalcitonin, and C-reactive protein, were compared with the IG% values. Results Twenty-six of the 117 patients were diagnosed with sepsis. The median IG% value was 2.6% (95% CI: 1.4–3.1). The area under the receiver operating characteristic curve was 0.77 (95% CI: 0.78–0.84) and the optimal cut-off value was 3%, with a sensitivity of 76.9% and specificity of 68.1%. The partial dependence plot of IG% on predicting sepsis showed that an IG% < 4% had low predictability, but increased thereafter. The interaction plot of IG% and C-reactive protein showed an increase in sepsis probability at an IG% of 6% and C-reactive protein of 160 mg/L. Conclusions IG% is moderately useful for predicting sepsis. However, since it can be determined from routine laboratory test results and requires no additional intervention or cost, it could be particularly useful as an auxiliary marker.

Expansion potential of skin grafts with novel I-shaped auxetic incisions

Severe burn injures lead to millions of fatalities every year due to lack of skin replacements. While skin is a very limited and expensive entity, split thickness skin grafting, which involves the projection of a parallel incision pattern on a small section of healthy excised skin, is typically employed to increase the expansion and cover a larger burn site. To date, the real expansion capacity of such grafts are low (<3 times) and insufficient for treatment of severe burn injuries. In this study, novel I-shaped auxetic incision patterns, which are known to exhibit high negative Poisson’s ratios, have been tested on the skin to investigate their expansion potential. Fourteen two-layer skin graft models with varying incision pattern parameters (i.e., length, spacing, and orientation) were developed using finite element modelling and tested under uniaxial and biaxial tensile loads. The Poisson’s ratio, meshing ratios, and induced stresses were quantified across all models. Graft models tested uniaxially along the orthogonal directions indicated opposite trends in generated Poisson’s ratios, as the length of the I-shape incisions were increased. Biaxially, with a symmetric and closely spaced I-shape pattern, graft meshing ratios up to 15.65 were achieved without overstressing the skin. Overall, the findings from the study indicated that expansion potentials much higher than that of traditional skin grafts can be achieved with novel I-shaped auxetic skin grafts, which would be indispensable for covering large wounds in severe burn injuries.

A preliminary study for an intraoperative 3D bioprinting treatment of severe burn injuries.

Background: Intraoperative three-dimensional (3D) fabrication of living tissues could be the next biomedical revolution in patient treatment. Approach: We developed a surgery-ready robotic 3D bioprinter and demonstrated that a bioprinting procedure using medical grade hydrogel could be performed using a 6-axis robotic arm in vivo for treating burn injuries.Results: We conducted a pilot swine animal study on a deep third-degree severe burn model. We observed that the use of cell-laden bioink as treatment substantially affects skin regeneration, producing in situ fibroblast growth factor (FGF) and vascular endothelial growth factor (VEGF), necessary for tissue regeneration and re-epidermalization of the wound. Innovation and Conclusion: We described an animal study of intraoperative 3D bioprinting living tissue. This emerging technology brings the first proof of in vivo skin printing feasibility using a surgery-ready robotic arm-based bioprinter. Our positive outcome in skin regeneration, joined with this procedure's feasibility, allow us to envision the possibility of using this innovative approach in a human clinical trial in the near future.