Gene profiling in muscle of severely burned children: age- and sex-dependent changes.

Background: Thermal injury is associated with a pronounced catabolic response in skeletal muscle. This study identifies gene expression changes in skeletal muscle of thermally injured girls and boys using high-density oligonucleotide arrays.
Methods: Six burned children with a mean age of 8.3 +/- 1.3 years and TBSA burn size covering 51 +/- 6% admitted to our hospital with in 48 h of injury and six cleft lip and cleft palate patients were studied. Total RNA was isolated, in vitro transcribed, and hybridized to HG-U95 Av.2 Affymetrix arrays. Messenger RNA expression patterns of controls and burn patients were compared using Affymetrix GeneChip Analysis Suite 5.2 and dChip.
Results: Statistical analysis of the 12,625 genes on each array showed a significant increase in the expression of 77 genes in burn children and a decrease in 21 genes when compared to controls (P < 0.05). We found three genes in burned males and two genes in burned females with decreased expression in muscle compared to controls. Chromosomes 1, 2, 7, 12, and 16 showed genes with increased expression in muscle from burned children, while chromosomes 3, 7, 8, 19, and 22 had genes with decreased expression. Categories of genes affected were related to metabolism, proliferation, transcription/translation, immune response, stress response, angiogenesis, and signal transduction.
Conclusions: Genes that are differentially expressed in skeletal muscle of burned children, but whose function in muscle is unknown, include those related to various transcription factors and those known to encode proteins involved in signaling pathways. Further analysis is required to achieve the ultimate goal of making functionally relevant conclusions about the molecular pathology of burn injury.