As we age, our bones grow more brittle and more susceptible to fracture. Individuals with diabetes or with certain types of osteoporosis often are similarly afflicted with brittle bones.
A new study from biomedical engineers at Rensselaer demonstrates how the compound N-phenacylthiazolium bromide, or PTB, dissolves the sugary impurities within bone tissue that cause our femurs, fibulas, and other bones to become more fragile.
Using PTB to reduce bone fragility and boost bone flexibility could lead to new strategies for preventing bone fractures in elderly individuals, as well as accelerated bone healing in patients with diabetes or osteoporosis.
“This study opens the door to new ways of thinking about the well-established, highly serious problem of brittle bones,” said Deepak Vashishth, professor of biomedical engineering and director of the Center for Biotechnology and Interdisciplinary Studies (CBIS), who led the study. “These research findings are an important milestone on the path to our long-term goal of realizing a drug-based intervention for reducing age-related changes in bone tissue.”
Biomedical engineering graduate Brian Bradke, who received his undergraduate degree in 2003 and his doctoral degree earlier this year, was co-author of the paper.
“This study opens the door to new ways of thinking about the well-established, highly serious problem of brittle bones.” —Deepak Vashishth
Bones are constantly being remodeled within the human body. Cells produce acids and proteases to break down minerals and proteins in the bone, which are then resorbed into the body. At the same time, to compensate for the resorbed tissue, bones are fortified through chemical deposition and mineralization. This ongoing remodeling process slows down as cells are unable to fully remove bone containing sugary impurities called advanced glycation end-products, or AGEs, which form naturally in proteins.
Bone remodeling slows with age, meaning AGEs accumulate at a great rate as we grow older. Individuals with diabetes, certain types of osteoporosis, or metabolic bone diseases are also known to have above-average AGE content. Higher concentrations of AGEs make these groups more susceptible to bone fracture and longer healing time for bone injuries.
“Once proteins in bone are modified, or cross-linked, they can no longer be digested by protease or resorbed by the body,” Vashishth said. “When this happens, the affected bones essentially freeze in time, unable to regenerate. This is a huge problem.”
The chemical PTB has previously been shown to be effective for dissolving AGEs and reducing stiffness in blood vessels for cardiovascular applications. Vashishth said his new study is the first to investigate the affect of PTB on bones.
He and Bradke applied PTB using different methods to multiple samples of human bones, taken from male donors between the ages of 19 and 80. The researchers tested the strength of the bones and used fluorescence to measure the amount of AGEs in the bones.
Compared to the control groups, bones treated with PTB showed a significant decrease in AGE content, as well as significant increase in flexibility, without losing calcium. The data suggests that treatment with PTB could be an effective means to reduce AGE content and decrease bone fragility caused by the modification, or cross-linking, of bone protein, Vashishth said.