Serum proteomic analysis of sex differences during an acute low back pain episode

Growing evidence suggests that pain and injury engage biological processes
and systems that extend beyond the nervous system. The molecular processes
driving the transition from acute to chronic low back pain (LBP) remain
poorly understood. Here, we explore the serum proteomic profile of male
and female participants during an acute LBP episode (N=59). Differential
protein expression during the acute-stage of LBP was compared between
participants with resolved LBP at three months and those with chronic or
recurrent LBP at three-months. Proteome-wide analysis using
mass-spectrometry identified 216 proteins confidently. Sex differences in
protein abundance changes were evident upon inspection of fold changes.
Multivariable data analysis identified 21 serum proteins during the acute
episode that correctly classified 93% of males and 23 serum proteins that
correctly classified 90% of females with ongoing LBP at three months. Most
of the differentially expressed proteins during acute LBP were involved in
immune, inflammatory, complement or coagulation responses. Overall, males
who recovered from an acute LBP episode had a greater tendency to
demonstrate an upregulated immune-driven inflammatory response during
acute LBP, whilst women with pain resolution demonstrated a tendency
towards a downregulated immune response. Taken together, this study
provides data to suggest biological processes during an acute LBP episode
may contribute to resolution, or persistence, of LBP symptoms at three
months, however, these processes differ between sexes. This work provides
an early foundation for future research exploring strategies targeting
distinct immune system processes in men and women that may interfere with
the transition from acute to chronic LBP.