Urinary Proteomic Biomarkers of Trabecular Bone Volume Change during Army Basic Combat Training.

PURPOSE:Optimize a dMS-based urinary proteomic technique and evaluate the relationship between urinary proteome content and adaptive changes in bone microarchitecture during BCT. METHODS:Urinary proteomes were analyzed with an optimized dMS technique in two groups of 13 recruits (n = 26) at the beginning (Pre) and end (Post) of BCT. Matched by age (21 ± 4 yr), sex (16 W), and baseline tibial trabecular bone volume fractions (Tb.BV/TV), these groups were distinguished by the most substantial (High) and minimal (Low) improvements in Tb.BV/TV. Differential protein expression was analyzed with mixed permutation ANOVA and false discovery proportion-based adjustment for multiple comparisons. RESULTS:Tibial Tb.BV/TV increased from pre- to post-BCT in High (3.30 ± 1.64%, p < 0.0001) but not Low (-0.35 ± 1.25%, p = 0.4707). The optimized dMS technique identified 10,431 peptides from 1,368 protein groups that represented 165 integrative biological processes. 74 urinary proteins changed from pre- to post-BCT (p = 0.0019) and neutrophil mediated immunity was the most prominent ontology. Two proteins (Immunoglobulin heavy constant gamma 4 and C-type lectin domain family 4 member G) differed from pre- to post-BCT in High and Low (p = 0.0006). CONCLUSIONS:The dMS technique can identify more than 1000 urinary proteins. At least 74 proteins are responsive to BCT, and other principally immune system-related proteins show differential expression patterns that coincide with adaptive bone formation.