Unravelling the puzzle of ageing bones

ONE IN five men and more than half of all women over the age 50 will develop a fracture due to osteoporosis during their lifetime…

ONE IN five men and more than half of all women over the age 50 will develop a fracture due to osteoporosis during their lifetime. Innovative research into stem-cell mechanics being carried out at NUI Galway offers new hope in the battle against this and other debilitating orthopaedic disorders, writes BETH O'DONOGHUE

Prof Glen Niebur, an expert in biomechanical engineering, is spending a year at NUIG to take part in this world-class research. He aims to investigate how various mechanical forces produced during normal physical movement affect the development processes of adult stem cells found in the bone marrow.

“We all hear that if you do plenty of exercise and eat well your bones will stay healthy. But that isn’t really the reality. No matter how much you exercise, your bones get weaker with age,” says Niebur.

Adult stem cells function to replace damaged and old tissues in the body. These cells are found in the bone marrow which lies inside certain bones. The stem cells act like master cells in that they can develop into a number of different cell types. Adult stem cells in the bone marrow can become bone or cartilage or fat, however as we become older they don’t tend to make bone or cartilage.

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“My primary hope is that will give me insight into how bone changes when we age and how this affects stem cell populations in bone,” says Niebur, who is visiting NUIG from the aerospace and mechanical engineering department at the University of Notre Dame in the US.

“There are lots of stem cells in this area. It seems that bones should be very healthy. The question is, are there things these cells need to encourage them to become bone cells?”

Answers to this and similar questions are vitally important for the development of new bone tissue repair and renewal treatments. Niebur has worked with NUIG researchers to develop an experimental bioreactor system and computer modelling processes.

These allow the researchers to study the role and fate of stem cells in bone and bone marrow during aging and disease.

The research will help scientists gain an understanding into how various mechanical forces encourage adult stem cells to form different cell types. “What we’re doing is making a bioreactor and putting pieces of live bone inside this, keeping the bone alive so that we can look at the effects of different stimuli,” he says.

The project is being carried out by scientists at the National Centre for Biomechanical Engineering Science (NCBES) and the Regenerative Medicine Institute (REMEDI) at the university. Niebur’s visit is funded by Science Foundation Ireland under the Walton Visiting Scholars Programme.

The scientists’ findings will have important implications for the diagnosis and treatment of many skeletal diseases, including osteoporosis, according to the research team.

Osteoporosis is a disease associated with a major loss in bone mineral density and strength. People with osteoporosis tend to have a lot more fat cells in their bone marrow, but it is not known how the two are linked, according to Niebur.

Do people develop osteoporosis because they have more fat cells in their bone marrow or is this caused by osteoporosis? If the researchers can solve this puzzle it will open up new ways to detect the disease at an earlier stage, he says.

“The ultimate goal is to understand the interplay between bone, bone marrow and stem cells to provide treatments in future for osteoporosis, or at least slow the process.”