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Bone marrow is the tissue that fills the cavities of bones. Bone marrow exists in two types: yellow and red. Yellow marrow consists mostly of fat cells whereas red marrow is a haematopoietic tissue involved in producing erythrocytes and leukocytes.
Soluble urokinase plasminogen activator receptor (suPAR) is a circulating biomarker of inflammation. A recent study identifies immature myeloid cells in the bone marrow as a major cellular source of suPAR that contributes to kidney disease.
Two anatomical niches for hematopoietic stem cells (HSCs) have been reported in the
bone marrow, but a distinct function for each of these niches has remained unclear. A new
role in stem cell proliferation has now been identified for the adhesion molecule E-selectin
expressed by bone marrow endothelial cells at the vascular niche (pages 1651–1657).