The Changing Balance Between Osteoblastogenesis and Adipogenesis in Aging and its Impact on Hematopoiesis

Abstract

Osteoblasts (OBs) and adipocytes (APs) share a common mesenchymal ancestor. It is now clear that mesenchymal stem cell (MSC) maturation along the OB lineage comes at the expense of adipogenesis and vice versa. During aging, this balance increasingly favors the formation of APs. Hematopoiesis also slowly declines during the aging process. The role of OB lineage cells in hematopoiesis has been studied, but less is known about how APs regulate hematopoiesis. A few studies have demonstrated a negative relationship between APs and hematopoiesis; however, there is also evidence that brown adipose tissue (BAT) may promote hematopoiesis. This review will examine the current knowledge of how adipogenesis and osteogenesis change with aging and the implications of this changing environment on hematopoeisis.

Identification of a CD133−CD55− population functions as a fetal common skeletal progenitor

“…Similarly, we did not observe significant contribution of CD133−CD55− common progenitors to adipocyte in ectopic bone forming assay, suggesting CD133−CD55− common progenitors are not the usual source of adipocytes. It fits the observation that adipogenesis in marrow is usually a later event in adult bone36. In contrast to OCR stem cell that did not overlap with perivascular mesenchymal progenitors, we found the fetal CD133−CD55− common progenitors give rise to adult perivascular mesenchymal progenitors in ectopic bone grafts.…”

High plasma osteocalcin is associated with low blood haemoglobin in elderly men: the MrOS Sweden Study

“…The balance between osteoblastogenesis and adipogenesis changes with age. Adipocytes predominantly suppress haematopoiesis in the BM of elderly subjects, whereas haematopoiesis is balanced by support from osteoblastic cells and suppression from adipocytes at younger ages . We and others have also previously demonstrated that the adipocyte‐derived protein adiponectin was negatively associated with erythropoiesis in men .…”

Age Related Changes in Bone Marrow Mesenchymal Stromal Cells: A Potential Impact on Osteoporosis and Osteoarthritis Development

“…6 One of the key cellular players in bone physiology is the osteoblast, a bone-forming cell derived from BM resident mesenchymal stromal cells (MSCs). BM-MSCs are selfrenewing in vivo, and the shift in their differentiation from osteogenic to adipogenic lineage with increase in age [7][8][9][10] can potentially affect osteoblast formation and bone remodeling, in general, and thus be a factor in OP and OA development and pathogenesis. In vitro expanded MSCs have broadly been defined by their adherence to plastic, ability to give rise to at least 3 cell lineages (adipogenic, osteogenic, and chondrogenic); presence of CD73, CD90, and CD105 surface molecules; and absence of CD11b or CD14, CD19 or CD79a, CD34, CD45, and human leukocyte antigen-antigen D related (human leukocyte antigen-antigen D related [HLA-DR])-as defined by the International Society for Cellular Therapy.…”