Serial Changes of Heat Shock Protein 70 and Interleukin-8 in Burn Blister Fluid

FAS(APO), DAMP, and AKT Phosphoproteins Expression Predict the Development of Nosocomial Infection After Pediatric Burn Injury

Pediatric burn injuries are a leading cause of morbidity with infections being the most common acute complication. Thermal injuries elicit a heightened cytokine response while suppressing immune function; however, the mechanisms leading to this dysfunction are still unknown. Our aim was to identify extracellular proteins and circulating phosphoprotein expression in the plasma after burn injury to predict the development of nosocomial infection (NI). Plasma was collected within 72 hours after injury from 64 pediatric burn subjects; of these, 18 went on to develop an NI. Extracellular damage-associated molecular proteins, FAS(APO), and protein kinase b (AKT) signaling phosphoproteins were analyzed. Subjects who went on to develop an NI had elevated high-mobility group box 1, heat shock protein 90 (HSP90), and FAS expression than those who did not develop an NI after injury (NoNI). Concurrently, phosphorylated (p-)AKT and mammalian target of rapamycin (p-mTOR) were elevated in those subjects who went on to develop an NI. Quadratic discriminant analysis revealed distinct differential profiles between NI and NoNI burn subjects using HSP90, FAS, and p-mTOR. The area under the receiver-operator characteristic curves displayed significant ability to distinguish between these 2 burn subject cohorts. These findings provide insight into predicting the signaling proteins involved in the development of NI in pediatric burn patients. Further, these proteins show promise as a diagnostic tool for pediatric burn patients at risk of developing infection while additional investigation may lead to potential therapeutics to prevent NI.

A novel human ex vivo skin model to study early local responses to burn injuries

Burn injuries initiate numerous processes such as heat shock response, inflammation and tissue regeneration. Reliable burn models are needed to elucidate the exact sequence of local events to be able to better predict when local inflammation triggers systemic inflammatory processes. In contrast to other ex vivo skin culture approaches, we used fresh abdominal skin explants to introduce contact burn injuries. Histological and ultrastructural analyses confirmed a partial-thickness burn pathology. Gene expression patterns and cytokine production profiles of key mediators of the local inflammation, heat shock response, and tissue regeneration were analyzed for 24 h after burn injury. We found significantly increased expression of factors involved in tissue regeneration and inflammation soon after burn injury. To investigate purely inflammation-mediated reactions we injected lipopolysaccharide into the dermis. In comparison to burn injury, lipopolysaccharide injection initiated an inflammatory response while expression patterns of heat shock and tissue regeneration genes were unaffected for the duration of the experiment. This novel ex vivo human skin model is suitable to study the local, early responses to skin injuries such as burns while maintaining an intact overall tissue structure and it gives valuable insights into local mechanisms at the very beginning of the wound healing process after burn injuries.