Skull bone marrow expands throughout life
The ability of the bone marrow to produce healthy blood cells declines significantly with age, leading to age-related inflammation and disease. A team of researchers at the Max Planck Institute for Molecular Biomedicine in Münster, Germany, has shown that the skull bone marrow is a exception to bone marrow aging and actually increases blood production throughout life. Specialized blood vessels within the skull bone marrow also continue to grow and drive this expansion, making this a unique case of lifelong vascular growth in the aging body.
The bone marrow microenvironment governs the self-renewal and fate of hematopoietic stem cells, which make all the blood cells in our body. This sophisticated and finely tuned network of hematopoietic stem cell maintenance is disrupted during aging, leading to disproportionate production of immune cells and an overall decline in their function. Blood vessels, a critical component of this niche, decrease in number and lose functional integrity in most organs during aging. Excessive fat accumulation, bone loss, severe inflammation, and a strong bias for myeloid cells over lymphocytes are also major hallmarks of the bone marrow aging.
Most bones in our body contain bone marrow, but long bones, such as arms and legs, and flat bones, such as the skull, are formed through different developmental and ossification processes. The mouse skull, due to its thin and nearly-transparent physical properties, has long been used as an intravital imaging platform to follow hematopoietic stem cell activity in the bone marrow of living mice, assuming that all bone marrow microenvironments in different bones are comparable.
