The Abundance of Trace Elements in Human Bone Relative to Bone Type and Bone Pathology

As the global population ages and the proportion of individuals afflicted with musculoskeletal disease spirals upward, there is an increasing interest in understanding and preventing bone-related diseases. Bone diseases, such as osteoporosis and osteoarthritis, are known to be influenced by a variety of factors including age, gender, nutrition, and genetics, but are also inherently linked to the human body's ability to produce biominerals of suitable quality. Because the crystal lattice structure and mineralogy of bone hydroxyapatite is surprisingly analogous to geological hydroxyapatite, trace element levels and exposure have long been proposed to influence the structure of biominerals as they do geological minerals (e.g., strontium substitution changes the crystal lattice of bone minerals, while toxic lead disrupt bone cellular processes leading to bone disease). Here, we explore the distribution of trace elements in human bones to evaluate the distribution of these elements with respect to bone type (cortical vs. trabecular) and bone disease (osteoarthritis vs. osteoporosis). We find higher concentrations of many metabolically active transition metals, as well as lead, in cortical bone compared to trabecular bone. When compared to patients who have osteoarthritis, and thus presumably normal bone minerals, osteoporosis patients have higher concentrations of scandium and chromium (Cr) in trabecular bone, and Cr and lead in cortical bone. Lower concentrations of bariumand titanium are associated with osteoporotic trabecular bone. This survey is an exploratory cross-sectional geochemical examination of several trace element concentrations previously understudied in human bone minerals. Plain Language Summary Bone-related diseases, like osteoporosis, are a growing concern as the global population ages. There are many factors which can influence bone health, including age, sex, and genetics, but ultimately osteoporosis is a disease of bone mass and bone strength. Bone minerals are like minerals found in nature, which contain trace element impurities. When these impurities occur in bones, they affect bone strength, with some trace elements increasing bone strength, and others decreasing it. The amount and kind of trace elements found in bone can be affected by environmental exposures or from the body's own processes which may be different between healthy and diseased individuals. This study compares the concentrations of 16 trace elements in bones from people with osteoporosis, a disease where bones themselves are diseased, and osteoarthritis, as disease of joint cartilage that is not expected to impact the trace element chemistry of bone minerals. We find that bones from osteoporosis patients have higher concentrations of some elements, including toxic lead, but lower concentrations of other elements. The location of these element deficiencies or excesses in the bones may suggest if their concentrations are more likely to be a cause of osteoporosis or a symptom of it.

Automated summary

As the global population ages and the number of people with musculoskeletal diseases increases, there is a growing interest in understanding and preventing bone-related diseases. This study explores the distribution of trace elements in human bones and their relationship to bone type and diseases such as osteoarthritis and osteoporosis.