Postsurgical Acute Phase Reaction is Associated with Decreased Levels of Circulating Myostatin.

Muscle strength is of importance for postsurgical rehabilitation. Myostatin is a growth factor that regulates the size of muscles and could thus influence muscle mass and function in the postsurgical period. The aim of the present study was to study the changes in myostatin levels during the postsurgical inflammatory period. Myostatin was analysed in serum samples from two elective surgery groups, orthopaedic surgery (n = 24) and coronary bypass patients (n = 21). The samples were collected prior to surgery and 4 and 30 days after surgery. In the orthopaedic group, the median myostatin levels decreased from 3582 ng/L prior to surgery to 774 ng/L at day 4 (p < 0.001) and to 2016 ng/L at day 30 (p < 0.001). Median CRP increased from 2.35 mg/L preoperatively to 117 mg/L at day 4 and decreased to 5.5 mg/L at day 30 in the same group. The coronary bypass group showed a similar pattern with a decrease in myostatin from 4212 ng/L to 2574 ng/L at day 4 (p < 0.001) and to 2808 ng/L at day 30 (p = 0.002). Median CRP increased from 1.80 mg/L preoperatively to 136 mg/L at day 4 and returned to 6.12 mg/L at day 30 in the coronary bypass group. There was a significant decrease in myostatin concentrations both in the early and late postsurgical period. The lowest myostatin concentration time point coincided with the highest CRP concentration time point.