Evaluation of Marrow Granulocytic Reserves in Normal and Disease States

Abstract

Recent concepts of the relationship of the blood granulocyte mass to the marrow reserve of granulocytes have been reviewed. Evidence has been presented to show that the marrow is the chief area of granulocyte "reserves" or "stores." The development of acute leukocytosis in response to a stimulus such as the intravenous injection of bacterial endotoxin depends upon release of cells from the intramedullary pool of granulocytes. The turnover of the marrow granulocyte reserve (MGR) is an orderly process in the steady state, and determines the form of the curve of DNA-labeled granulocytes in the peripheral blood. From estimates of the turnover time of the MGR it appears that the granulocyte spends an average time of about 10 hours in the peripheral blood. Granulocytes do not appear to recirculate once they have left the peripheral blood and have entered the tissues. However, granulocytes may be sequestered within capillary beds for variable periods, and may re-enter the circulating blood from such areas. Such cells are not to be considered as having re-entered the blood from the tissues. The intravenous injection of a purified bacterial lipopolysaccharide as a stimulus to acute leukocytosis is described. The possbile usefulness of this procedure in assessing the MGR is discussed.

Granulocyte macrophage colony stimulating factor induced changes in cellular adhesion molecule expression and adhesion to endothelium: in‐vitro and in‐vivo studies in man

“…These studies show that the leucopenia associated with rhGM-CSF administration is due to a transient shift of leucocytes into the marginated pool and that the recovery is due to re-entry of these cells into the circulation. A similar leucopenia is observed during haemodialysis or endotoxaemia (Craddock et al 1960) and with infusions of chemotactic factors in animals (O'Flaherty et al, 1977). Haemodialysis leucopenia is thought to be due to activation of the alternative complement pathway on the dialysis membrane and generation of chemotactic complement fragments (Craddock et al,19 77).…”

Motion Picture Studies on Degranulation of Horse Eosinophils During Phagocytosis

“…They are produced in bone marrow from undifferentiated stem cells, requiring approximately 4 days for maturation (8). ~Upon release from the marrow, both types of cells stay in the circulation for only a few hours (9)(10)(11), and pass into the tissues. Both are found in relatively large numbers in skin, respiratory tract, and intestinal membranes (11), i.e.…”

Human Mesenchymal Stem Cells Inhibit Neutrophil Apoptosis: A Model for Neutrophil Preservation in the Bone Marrow Niche

“…The bone marrow is not only the organ where hematopoiesis occurs but also the site where a large amount of nonproliferating neutrophils are retained in the storage pool of bone marrow sinusoids [24, 25]. The bone marrow reserve, whose mass has been estimated to be 25–30 times larger than the circulating mass of granulocytes, represents in conditions of increased demand a readily available source of neutrophils that possess the same functional properties as their peripheral counterparts [24, 26, 27].…”

“…The bone marrow is not only the organ where hematopoiesis occurs but also the site where a large amount of nonproliferating neutrophils are retained in the storage pool of bone marrow sinusoids [24, 25]. The bone marrow reserve, whose mass has been estimated to be 25–30 times larger than the circulating mass of granulocytes, represents in conditions of increased demand a readily available source of neutrophils that possess the same functional properties as their peripheral counterparts [24, 26, 27]. Interestingly, MSC, which exert their homeostatic functions through both paracrine mechanisms involving the release of soluble factors and contact‐dependent mechanisms, would line the bone marrow extravascular space, forming a network that interpolates with the sinusoids, where neutrophils of the bone marrow reserve reside [28].…”