Concentrations of urinary neopterin, but not suPAR, positively correlate with age in rhesus macaques

• Published in: Frontiers in ecology and evolution Vol. 10
• Main Authors: Cooper, Eve B., Watowich, Marina M., Beeby, Nina, Whalen, Connor, Montague, Michael J., Brent, Lauren J. N., Snyder-Mackler, Noah, Higham, James P.
• Format: Journal Article
• Language: English
• Published: Frontiers Media S.A 28.10.2022
• Subjects: aging; gene expression; immunosenescence; inflammaging; neopterin; suPAR
• ISSN: 2296-701X; 2296-701X
• DOI: 10.3389/fevo.2022.1007052

Identifying biomarkers of age-related changes in immune system functioning that can be measured non-invasively is a significant step in progressing research on immunosenescence and inflammaging in free-ranging and wild animal populations. In the present study, we aimed to investigate the suitability of two urinary compounds, neopterin and suPAR, as biomarkers of age-related changes in immune activation and inflammation in a free-ranging rhesus macaque ( Macaca mulatta ) population. We also investigated age-associated variation in gene transcription from blood samples to understand the underlying proximate mechanisms that drive age-related changes in urinary neopterin or suPAR. Neopterin was significantly positively correlated with age, and had a moderate within-individual repeatability, indicating it is applicable as a biomarker of age-related changes. The age-related changes in urinary neopterin are not apparently driven by an age-related increase in the primary signaler of neopterin, IFN-y, but may be driven instead by an age-related increase in both CD14+ and CD14− monocytes. suPAR was not correlated with age, and had low repeatability within-individuals, indicating that it is likely better suited to measure acute inflammation rather than chronic age-related increases in inflammation (i.e., “inflammaging”). Neopterin and suPAR had a correlation of 25%, indicating that they likely often signal different processes, which if disentangled could provide a nuanced picture of immune-system function and inflammation when measured in tandem.