Serum biomarkers that predict lean mass loss over bed rest in older adults: An exploratory study.

Abstract Background Lean mass (LM) loss during extended bed rest contributes to long term functional decline in older adults. Identifying blood biomarkers that predict a hospitalized individual’s risk of losing LM could allow for timely intervention. Methods LM from 19 healthy subjects (age 60–76 y, 4 males, 15 females), who were confined to 10 days of complete bed rest, was measured pre- and post-bed rest. One hundred eighty-seven biomarkers from pre-bed rest fasted serum samples were obtained from all evaluable subjects (n = 18), analyzed using multiplexed immunoassay array and pooled. Decision tree analysis was used to identify pre-bed rest markers that predict LM loss over bed rest. Results Sixty-three markers were excluded due to being below assay detection limits. One pair of markers, Tissue inhibitor of metalloprotease-1 (TIMP1) and tenascin C (TNC), were found to correlate with percent change in total LM over bed rest: [R2 = 0.71, all subjects; R2 = 0.76, females]. Subjects with pre-bed rest TIMP1 ≥ 141 ng/ml had the highest loss of total LM over bed rest, whereas subjects with pre-bed rest TIMP1  Conclusions Panels of blood biomarkers associated with the muscle extracellular matrix may predict the likelihood for LM loss over extended bed rest.