Table 1.

Factors and cytokines associated with bone mass regulation

Factor	Derivation	Effect	Reference
Notch	osteoblasts osteocytes	Bidirectional bone formation and absorption	[23–25]
TNF-α IL-1β IL-6	Dendritic cell Macrophage	Increases bone absorption	[11]
RANKL	osteoblasts osteocytes Dendritic cell Adipocyte Fibroblast	Osteoclast differentiation and development Essential for bone absorption	[12]
OPG	osteoblasts osteocytes	RANKL inhibition Bone protection	[10]
PPAR-γ	Adipocyte	Inhibits bone formation Increases bone absorption	[18]
Leptin	Adipocyte	Increased osteoblast differentiation of MSCs Promotes bone formation Inhibits adipocyte accumulation	[20]
Adiponectin	Adipocyte	Increases bone formation Inhibits adipocyte accumulation	[20]