New insight into the mouse blood stem cell aging process

Healthy red blood cells.New research has identified changes in the microenvironment of the bone marrow that contributes to the aging process of blood (hematopoietic) stem cells (HSCs). The HSC is a type of adult stem cell found in the bone marrow that can self-renew and develop into any type of white blood cell (e.g., B-cell, T-cell, and natural killer cell), oxygen-carrying red blood cells, and a variety of immune cells (e.g., megakaryocytes, monocytes). Because they can effectively regenerate any type of blood cell the body needs, HSCs are recognized as a new way to treat various diseases such as cancers, autoimmune diseases, and nonmalignant blood diseases such as sickle cell disease. However, previous research has shown that for unknown reasons, as people age, the capacity of their HSCs to develop into different types of blood cells diminishes.

In this study, investigators sought out changes in the aging bone marrow of mice that may contribute to the diminished capacity of HSCs to develop into different types of blood cells. They reported that characteristic hallmarks of aging HSCs in middle-aged female mice are linked to a reduction in the level of a hormone called insulin-like growth factor 1 (IGF1) in the bone marrow. Interestingly, IGF1 treatment of HSCs from middle-aged female mice restored characteristics of younger, healthier HSCs. These findings suggest that therapeutic strategies aimed at increasing IGF1 levels in the bone marrow may be able to halt or partially reverse HSC aging, and, thereby, boost HSC function through middle age and perhaps longer.