Our bone marrow, the fatty and jelly-like substance inside our bones, works quietly but efficiently, producing an impressive 500 billion new blood cells every day. This remarkable process is made possible by hematopoietic stem cells, which are responsible for creating all types of blood cells in our bodies and renewing themselves to maintain the continuous blood production line.
Similar to any complex system, hematopoietic stem cells experience a decline in function as they age, increasing the risk of developing serious diseases such as blood cancers. While it is known that the risk of aging-related diseases varies among individuals, little is understood about whether hematopoietic stem cells age differently across individuals.
Research led by Jennifer Trowbridge, a professor at the Jackson Laboratory, focused on studying hematopoietic stem cells at the individual level in middle-aged mice to explore how aging affects these cells. Despite all the mice being the same age, the study revealed that hematopoietic stem cells in their bone marrow aged differently from one another. Furthermore, the team could predict the function of these stem cells based on the activity of two growth factors, Kitl and Igf1, present in both mice and humans.
By analyzing the RNA transcriptome in mesenchymal stromal cells surrounding the stem cells, Trowbridge’s team observed that the decrease in these growth factors correlated with age-related changes in hematopoietic stem cells. This finding underscores the importance of these growth factors in the aging process of stem cells and suggests that the variations in hematopoietic stem cell aging could have significant implications for health outcomes in both mice and humans.
