Increased expression of inflammatory pathway genes in skeletal muscle during surgery.

Background & Aims: Postoperative insulin resistance, resulting in hyperglycemia, is strongly associated to morbidity and mortality in surgical patients but the underlying mechanisms are unclear. As increasing data suggests a link between inflammation and insulin resistance, we aimed to evaluate if the expression of inflammatory and insulin signaling genes is regulated in skeletal muscle during surgery.

Methods: Eight patients (4 females, 63 [46-69] years, body mass index 25.5 [16.5-29.8]kg/m(2)) undergoing major abdominal surgery were included. Biopsies from m. rectus abdominis were obtained at the beginning and at the end of the operation. mRNA levels of 45 genes were analyzed.

Results: The time elapsed between the two biopsies was 224 (198-310) min. An increased (p<0.05) expression was noted for genes encoding both inflammatory mediators, such as interleukin 6, tumor necrosis factor, and nuclear factor of kappa light polypeptide gene enhancer in B cells, and metabolic regulators, such as peroxisome proliferator-activated receptor delta, while the analysis did not detect significant expression changes of the insulin signaling pathway genes.

Conclusions: The observed gene expression changes in skeletal muscle during surgery occurred mainly in inflammatory pathways, suggesting a possible role for inflammation in the development of postoperative insulin resistance.