A single injection of stem cells could one day restore normal bone structure in patients with osteoporosis, say researchers who achieved this reversal in mice. The findings are published in Stem Cells Translational Medicine.
Globally, over 200 million people are living with either postmenopausal osteoporosis, which is known as type 1 osteoporosis and affects women in particular, or age-related type 2 osteoporosis, which both genders are prone to.
In type 2 osteoporosis, there is a reduction in the inner structure of the bone. The bone becomes thinner and less dense, and it can no longer function properly.
Worldwide, type 2 osteoporosis leads to around 8.9 million fractures annually, with hip fractures among the most common, leading to disability and even death.
Currently, there is only one drug available to treat type 2 osteoporosis, and its effectiveness lasts for only 2 years.
Stem cells are "progenitor" cells, which means they can divide and change to become any different type of cell. It was at the University of Toronto, Canada, that scientists first discovered stem cells in the 1960s.
Researchers from the University of Toronto and The Ottawa Hospital - also in Canada - wanted to find out if stem cell therapy could treat the problem of insufficient or faulty mesenchymal stem cells (MSCs) in mice.
MSCs boost regeneration of bone
MSCs are "a heterogeneous population of musculoskeletal progenitors that includes skeletal stem cells (SSCs)." MSCs can become bone cells, and they can be transplanted between individuals without needing to be matched, and without the risk of rejection.
The senior author of the study is Prof. William Stanford, who is a senior scientist at The Ottawa Hospital and professor at the University of Ottawa. In previous research, he found an association between defects in MSC and age-related osteoporosis in mice.
In the present study, researchers hypothesized that if osteoporosis results from faulty MSCs, transplanting healthy MSCs could have a therapeutic effect, so they injected MSCs from healthy mice into mice with osteoporosis.
After 6 months, which is a quarter of a mouse's life span, the team found that healthy functional bone had replaced the osteoporotic bone.
Coauthor Prof. John E. Davies says:
"We had hoped for a general increase in bone health. But the huge surprise was to find that the exquisite inner 'coral-like' architecture of the bone structure of the injected animals, which is severely compromised in osteoporosis, was restored to normal."
The researchers hope the findings could lead to a new way of treating osteoporosis, or even delaying its onset indefinitely.
In the US, elderly patients have received injections with MSCs as part of an ancillary trial, and the team plans to examine blood samples to see if biological markers indicate an improvement in bone growth and bone reabsorption.
Depending on the outcome, larger trials could follow within the next 5 years.