Blood protein levels, a critical biomarker for various health conditions, undergo significant changes from childhood to early adulthood, with notable gender differences. This groundbreaking study, published in Nature Communications, reveals that the protein landscape in our blood evolves over time, challenging the use of adult reference values for children and adolescents. The research, conducted by a team from Karolinska Institutet, analyzed blood samples from 100 participants in the BAMSE cohort at ages 4, 8, 16, and 24, measuring over 5,000 proteins. The findings indicate that more than half of these proteins changed with age, with the most dramatic shifts occurring between 8 and 16 years, a period coinciding with puberty. This period saw sharp increases in some proteins, followed by decreases in early adulthood, while others showed more gradual changes. The study emphasizes that blood protein levels are strongly age-dependent, even in early life, and that adult reference values may not be applicable to children and adolescents. This has significant implications for the use of blood proteins as biomarkers, as different levels in children may reflect normal development rather than disease. The researchers also identified clear gender differences, with around 30% of proteins differing between women and men by age 24, including those linked to growth, metabolism, the immune system, and reproductive processes. This highlights the importance of considering both age and gender as fundamental biological factors when using proteins as biomarkers. The study's senior author, Erik Melén, suggests that mapping protein development can create a reference for identifying early deviations, opening possibilities for risk assessment of chronic diseases and personalized medicine. However, the researchers caution that the study's limited number of participants and relatively homogeneous population may limit its generalizability. Despite this, the findings contribute to the Human Disease Blood Atlas, a resource within the Human Protein Atlas, and provide valuable insights into the dynamic nature of blood proteins and their role in health and disease.
