The Central Regulation of Bone Mass: Genetic Evidence and Molecular Bases

Stimulant use and bone health in US children and adolescents: analysis of the NHANES data

Stimulants have become the most popular psychopharmacologic drugs used in therapy for attention-deficit/hyperactivity disorder (ADHD). Childhood and adolescence are crucial periods for optimizing bone health to prevent osteoporosis-related fractures in old age. However, controversy remains regarding the relationship between stimulant use and bone health. The present study was designed to examine the bone mineral content (BMC) and bone mineral density (BMD) of 5472 individuals aged 8-16 years with or without stimulant use based on National Health and Nutrition Examination Survey (NHANES) 2011-2018 data and to further assess the association between stimulant use and bone health. Among these, 284 (5.2%) participants were using stimulants. In analyses stratified by sex, the BMC and BMD at the level of the lumbar spine, pelvis, and total body were generally lower among stimulant users than among nonusers in males (all P < 0.001), while the differences were not statistically significant in females. In multivariable linear regression models, the increasing range of BMCs and BMDs with age was lower in participants using stimulants than in those not using stimulants after fully adjusting for potential confounding factors. Compared to participants not using stimulants, stimulant use ≥ 3 months was associated with significantly lower BMCs [lumbar spine: β =  - 1.35, (95% CI: - 2.56, - 0.14); pelvis: β =  - 9.06, (95% CI: - 15.21, - 2.91); and total: β =  - 52.96, (95% CI: - 85.87, - 20.04)] and BMDs [pelvis: β =  - 0.03, (95% CI: - 0.04, - 0.01), total: β =  - 0.01, (95% CI: - 0.02, - 0.00)].

CONCLUSIONS

Children and adolescents using stimulants exhibited reductions in BMC and BMD at the lumbar spine, pelvis, and total body compared to those who were not using stimulants, especially among males.

WHAT IS KNOWN

• Childhood and adolescence are crucial periods for optimizing bone health to prevent osteoporosis-related fractures in old age. • Controversy remains regarding the relationship between stimulant use and bone health.

WHAT IS NEW

• The bone mineral content and bone mineral density at the level of the lumbar spine, pelvis, and total body were generally lower among stimulant users than among nonusers in males, while the differences were not statistically significant in females. • Body mass index and serum alkaline phosphatase may be predictors for loss of bone mineral content and bone mineral density in stimulant users.

Neurogenic Heterotopic Ossifications Recapitulate Hematopoietic Stem Cell Niche Development Within an Adult Osteogenic Muscle Environment

Hematopoiesis and bone interact in various developmental and pathological processes. Neurogenic heterotopic ossifications (NHO) are the formation of ectopic hematopoietic bones in peri-articular muscles that develop following severe lesions of the central nervous system such as traumatic cerebral or spinal injuries or strokes. This review will focus on the hematopoietic facet of NHO. The characterization of NHO demonstrates the presence of hematopoietic marrow in which quiescent hematopoietic stem cells (HSC) are maintained by a functional stromal microenvironment, thus documenting that NHOs are neo-formed ectopic HSC niches. Similarly to adult bone marrow, the NHO permissive environment supports HSC maintenance, proliferation and differentiation through bidirectional signaling with mesenchymal stromal cells and endothelial cells, involving cell adhesion molecules, membrane-bound growth factors, hormones, and secreted matrix proteins. The participation of the nervous system, macrophages and inflammatory cytokines including oncostatin M and transforming growth factor (TGF)-β in this process, reveals how neural circuitry fine-tunes the inflammatory response to generate hematopoietic bones in injured muscles. The localization of NHOs in the peri-articular muscle environment also suggests a role of muscle mesenchymal cells and bone metabolism in development of hematopoiesis in adults. Little is known about the establishment of bone marrow niches and the regulation of HSC cycling during fetal development. Similarities between NHO and development of fetal bones make NHOs an interesting model to study the establishment of bone marrow hematopoiesis during development. Conversely, identification of stage-specific factors that specify HSC developmental state during fetal bone development will give more mechanistic insights into NHO.