Exploratory plasma proteomic analysis in a randomized crossover trial of aspirin among healthy men and women

<div><p>Long-term use of aspirin is associated with lower risk of colorectal cancer and other cancers; however, the mechanism of chemopreventive effect of aspirin is not fully understood. Animal studies suggest that COX-2, NFκB signaling and Wnt/β-catenin pathways may play a role, but no clinical trials have systematically evaluated the biological response to aspirin in healthy humans. Using a high-density antibody array, we assessed the difference in plasma protein levels after 60 days of regular dose aspirin (325 mg/day) compared to placebo in a randomized double-blinded crossover trial of 44 healthy non-smoking men and women, aged 21–45 years. The plasma proteome was analyzed on an antibody microarray with ~3,300 full-length antibodies, printed in triplicate. Moderated paired t-tests were performed on individual antibodies, and gene-set analyses were performed based on KEGG and GO pathways. Among the 3,000 antibodies analyzed, statistically significant differences in plasma protein levels were observed for nine antibodies after adjusting for false discoveries (FDR adjusted p-value<0.1). The most significant protein was succinate dehydrogenase subunit C (SDHC), a key enzyme complex of the mitochondrial tricarboxylic acid (TCA) cycle. The other statistically significant proteins (NR2F1, MSI1, MYH1, FOXO1, KHDRBS3, NFKBIE, LYZ and IKZF1) are involved in multiple pathways, including DNA base-pair repair, inflammation and oncogenic pathways. None of the 258 KEGG and 1,139 GO pathways was found to be statistically significant after FDR adjustment. This study suggests several chemopreventive mechanisms of aspirin in humans, which have previously been reported to play a role in anti- or pro-carcinogenesis in cell systems; however, larger, confirmatory studies are needed.</p></div

Demographic characteristics of 44 participants.

<p>Demographic characteristics of 44 participants.</p

Proteins that differed significantly between aspirin and placebo periods with false discovery rate (FDR) <0.10.

<p>Proteins that differed significantly between aspirin and placebo periods with false discovery rate (FDR) <0.10.</p

Unadjusted Cox proportional hazards model for time to first CD4 ≤ 350 and time to composite disease progression endpoint.

<p>Unadjusted Cox proportional hazards model for time to first CD4 ≤ 350 and time to composite disease progression endpoint.</p

MTN-015 study population of participants from MTN-003 parent protocol.

<p>MTN-015 study population of participants from MTN-003 parent protocol.</p

Linear mixed effects model comparing HIV-1 RNA (log₁₀) and CD4 T-cell counts between the first result 90 days or more after the estimated HIV seroconversion date (intercept) and the 12-month visit (slope) by study arm.

<p>Linear mixed effects model comparing HIV-1 RNA (log₁₀) and CD4 T-cell counts between the first result 90 days or more after the estimated HIV seroconversion date (intercept) and the 12-month visit (slope) by study arm.</p