Inhibition of XXXX reverses age-associated decline in bone mass.

@entity71584 @entity19 @entity7097 @entity18707 @entity170 @entity622 @entity141 @entity5384
Decline in bone formation is a major contributing factor to the loss of bone mass associated with aging. We previously showed that the genetic ablation of the tissue-restricted and multifunctional @entity141 /calmodulin (CaM)-dependent protein kinase kinase 2 ( @entity71584 ) stimulates trabecular bone mass accrual, mainly by promoting anabolic pathways and inhibiting catabolic pathways of bone remodeling. In this study, we investigated whether inhibition of this kinase using its selective cell-permeable inhibitor @entity18707 will stimulate bone formation in 32 week old male @entity7097 @entity19 and reverse age-associated of decline in bone volume and strength. Tri-weekly intraperitoneal injections of saline or @entity18707 (10  M) were performed for six weeks followed by metabolic labeling with @entity5384 and @entity622 red. New bone formation was assessed by dynamic histomorphometry whereas micro-computed tomography was employed to measure trabecular bone volume, microarchitecture and femoral mid-shaft geometry. Cortical and trabecular bone biomechanical properties were assessed using three-point bending and punch compression methods respectively. Our results reveal that as they progress from 12 to 32 weeks of age, @entity7097 @entity19 sustain a significant decline in trabecular bone volume, microarchitecture and strength as well as cortical bone strength. However, treatment of the 32 week old @entity7097 @entity19 with @entity18707 stimulated apposition of new bone and completely reversed the age-associated decrease in bone volume, quality, as well as trabecular and cortical bone strength. We also observed that regardless of age, male @entity71584 (-/-) @entity19 possessed significantly elevated trabecular bone volume, microarchitecture and compressive strength as well as cortical bone strength compared to age-matched @entity7097 @entity19 , implying that the chronic loss of this kinase attenuates age-associated decline in bone mass. Further, whereas @entity18707 treatment and/or the absence of @entity71584 significantly enhanced the femoral mid-shaft geometry, the mid-shaft cortical wall thickness and material bending stress remained similar among the cohorts, implying that regardless of treatment, the material properties of the bone remain similar. Thus, our cumulative results provide evidence for the pharmacological inhibition of @entity71584 as a bone anabolic strategy in combating age-associated @entity170 .
