Figure 4.

Comparison of the effects of antiresorptive vs senolytic therapies on bone metabolism. (a) (1) Senescent cells (SCs) increase in the bone microenvironment with aging, where they (2) increase bone resorption by osteoclasts (OCs) and (3) reduce bone formation by osteoblasts (OBs). (4) Antiresorptive drugs inhibit or eliminate OCs and decrease bone resorption; (5) because of coupling between OCs and OBs, bone resorption is also reduced. (b) (1) Senolytic therapy reduces the burden of (2) SCs, which leads to (3) a reduction in bone resorption with (4) either an increase (cortical bone) or maintained (trabecular bone) bone formation, resulting in (5) a beneficial “uncoupling” between bone resorption and bone formation. Adapted from Farr et al. (29).