Measurement of Hepatic Protein Fractional Synthetic Rate with Stable Isotope Labeling Technique in Thapsigargin Stressed HepG2 Cells

Severe burn-induced liver damage and dysfunction is associated with endoplasmic reticulum (ER) stress. ER stress has been shown to regulate global protein synthesis. In the current study, we induced ER stress in vitro and estimated the effect of ER stress on hepatic protein synthesis. The aim was two-fold: (1) to establish an in vitro model to isotopically measure hepatic protein synthesis and (2) to evaluate protein fractional synthetic rate (FSR) in response to ER stress. Human hepatocellular carcinoma cells (HepG2) were cultured in medium supplemented with stable isotopes 1,2-13C2-glycine and L-[ring-13C6]phenylalanine. ER stress was induced by exposing the cells to 100 nM of thapsigargin (TG). Cell content was collected from day 0 to 14. Alterations in cytosolic calcium were measured by calcium imaging and ER stress markers were confirmed by Western blotting. The precursor and product enrichments were detected by GC-MS analysis for FSR calculation. We found that the hepatic protein FSR were 0.97±0.02 and 0.99±0.05%/hr calculated from 1,2-13C2-glycine and L-[ring-13C6]phenylalanine, respectively. TG depleted ER calcium stores and induced ER stress by upregulating p-IRE-1 and Bip. FSR dramatically decreased to 0.68±0.03 and 0.60±0.06%/hr in the TG treatment group (p<0.05, vs. control). TG-induced ER stress inhibited hepatic protein synthesis. The stable isotope tracer incorporation technique is a useful method for studying the effects of ER stress on hepatic protein synthesis

Targeting bacterial adherence inhibits multidrug-resistant Pseudomonas aeruginosa infection following burn injury

Classical antimicrobial drugs target proliferation and therefore place microbes under extreme selective pressure to evolve resistance. Alternative drugs that target bacterial virulence without impacting survival directly offer an attractive solution to this problem, but to date few such molecules have been discovered. We previously discovered a widespread group of bacterial adhesins, termed Multivalent Adhesion Molecules (MAMs) that are essential for initial binding of bacteria to host tissues and virulence. Thus, targeting MAM-based adherence is a promising strategy for displacing pathogens from host tissues and inhibiting infection. Here, we show that topical application of polymeric microbeads functionalized with the adhesin MAM7 to a burn infected with multidrug-resistant Pseudomonas aeruginosa substantially decreased bacterial loads in the wound and prevented the spread of the infection into adjacent tissues. As a consequence, the application of this adhesion inhibitor allowed for vascularization and wound healing, and maintained local and systemic inflammatory responses to the burn. We propose that MAM7-functionalized microbeads can be used as a topical treatment, to reduce bacterial attachment and hence prevent bacterial colonization and infection of wounds. As adhesion is not required for microbial survival, this anti-infective strategy has the potential to treat multidrug-resistant infections and limit the emergence of drug-resistant pathogens

Comparing the Effectiveness of Glucocorticoids in Preventing Hypertrophic Scar Diagnosis in Burn Patients

Background and Objectives: The prevalence of hypertrophic scarring after a burn is approximately 70%. Despite advances in burn management, there is currently no gold standard treatment to reduce or prevent its occurrence. Glucocorticoids are frequently given to patients early after burns for other therapeutic purposes and have been shown to induce scar regression. Therefore, the purpose of the present work is to determine the incidence of hypertrophic scar diagnosis in burn patients who were administered glucocorticoid treatment using TriNetX, a large patient database. Materials and Methods: Patients diagnosed with hypertrophic scarring, hypertrophic disorders of the skin, or scar conditions and fibrosis of the skin after burn injury were identified in the TriNetX database. The glucocorticoids investigated include hydrocortisone, methylprednisolone, dexamethasone, triamcinolone, and prednisone. Patients were stratified into three groups based on total body surface area (TBSA) burned: 0–19%, 20–39%, and 40–100%. The risk ratio was evaluated for burn patients who received varying glucocorticoids after injury based on TBSA burned. Additionally, treatment pathways, time of treatment, and treatment purity pathways were evaluated. Results: In patients with a 0–19% TBSA burn, methylprednisolone showed a decreased risk of developing hypertrophic scar diagnosis. In those with a 20–39% TBSA burn or 40–100% TBSA burn, dexamethasone showed an increased risk of developing hypertrophic scar diagnosis. Additionally, dexamethasone was the most commonly administered glucocorticoid for burn patients and was most likely to be administered earlier after burn injury, comparatively. Conclusions: Methylprednisolone was associated with reduced hypertrophic scar diagnosis in burn patients independent of TBSA burn. While glucocorticoids are one of the mainstay treatments for hypertrophic scarring, further studies are needed to determine early therapeutic interventions that will reduce the potential for hypertrophic scar development in burn patients

Acute muscle mass loss was alleviated with HMGB1 neutralizing antibody treatment in severe burned rats

Abstract Burn injury is associated with muscle wasting, though the involved signaling mechanisms are not well understood. In this study, we aimed to examine the role of high mobility group box 1 (HMGB1) in signaling hyper-inflammation and consequent skeletal muscle impairment after burn. Sprague Dawley rats were randomly assigned into three groups: (1) sham burn, (2) burn, (3) burn/treatment. Animals in group 2 and group 3 received scald burn on 30% of total body surface area (TBSA) and immediately treated with chicken IgY and anti-HMGB1 antibody, respectively. Muscle tissues and other samples were collected at 3-days after burn. Body mass and wet/dry weights of the hind limb muscles (total and individually) were substantially decreased in burn rats. Acute burn provoked the mitochondrial stress and cell death and enhanced the protein ubiquitination and LC3A/B levels that are involved in protein degradation in muscle tissues. Further, an increase in muscle inflammatory infiltrate associated with increased differentiation, maturation and proinflammatory activation of bone marrow myeloid cells and αβ CD4+ T and γδ T lymphocytes was noted in in circulation and spleen of burn rats. Treatment with one dose of HMGB1 neutralizing antibody reduced the burn wound size and preserved the wet/dry weights of the hind limb muscles associated with a control in the markers of cell death and autophagy pathways in burn rats. Further, anti-HMGB1 antibody inhibited the myeloid and T cells inflammatory activation and subsequent dysregulated inflammatory infiltrate in the muscle tissues of burn rats. We conclude that neutralization of HMGB1-dependent proteolytic and inflammatory responses has potential beneficial effects in preventing the muscle loss after severe burn injury

The Utilisation of INR to identify coagulopathy in burn patients.

Studies conflict on the significance of burn-induced coagulopathy. We posit that burn-induced coagulopathy is associated with injury severity in burns. Our purpose was to characterize coagulopathy profiles in burns and determine relationships between % total burn surface area (TBSA) burned and coagulopathy using the International Normalized Ratio (INR). Burned patients with INR values were identified in the TriNetX database and analyzed by %TBSA burned. Patients with history of transfusions, chronic hepatic failure, and those on anticoagulant medications were excluded. Interquartile ranges for INR in the burned study population were 1.2 (1.0-1.4). An INR of ≥ 1.5 was used to represent those with burn-induced coagulopathy as it fell outside the 3rd quartile. The population was stratified into subgroups using INR levels <1.5 or ≥1.5 on the day of injury. Data are average ± SD analyzed using chi-square; p < .05 was considered significant. There were 7,364 burned patients identified with INR <1.5, and 635 had INR ≥1.5. Comparing TBSA burned groups, burn-induced coagulopathy significantly increased in those with ≥20% TBSA; p = .048 at 20-29% TBSA, p = .0005 at 30-39% TBSA, and p < .0001 for 40% TBSA and above. Age played a significant factor with average age for those with burn-induced coagulopathy 59 ± 21.5 years and 46 ± 21.8 for those without (p < .0001). After matching for age, TBSA, and demographics, the risk of 28 day-mortality was higher in those with burn-induced coagulopathy compared to those without (risk difference 20.9%, p < .0001) and the odd ratio with 95% CI is 4.45 (3.399-5.825). Investigation of conditions associated with burn-induced coagulopathy showed the effect of heart diseases to be significant; 53% of patients with burn-induced coagulopathy had hypertension (p < .0001). Burn-induced coagulopathy increases with %TBSA burned. The information gained firmly reflects a link between %TBSA and burn-induced coagulopathy, which could be useful in prognosis and treatment decisions