GoKawiilOsteoporosis causes thin, porous bones that are prone to fracture, but a promising cell therapy might offer a way to strengthen them.Credit: Dr Tony Brain/SPL
The ten older women had, between them, broken their bones dozens of times, often after little more than a stumble. But after receiving a single infusion of their own bone-marrow cells, treated in the laboratory to help the cells penetrate bone tissue, the women’s fractures all but stopped.
Before treatment, the women — the participants of small clinical trial reported1 today in Cell — experienced fractures in their spines, hips, arms and other bones every year or two, on average. After the trial, the women experienced bone breaks caused by low-impact trauma at a rate closer to once per decade.
The results raise the tantalizing possibility that a one-time cell therapy could rebuild brittle bones in people with osteoporosis, an ageing-related condition that affects around 200 million women worldwide, particularly after menopause.
“It’s quite remarkable,” says Ajit Varki, a physician-scientist at the University of California, San Diego who was not involved in the study. The trial “showed an almost 100% efficacy sustained for several years — and no side effects”.
Still, the findings come with hefty caveats. The study was small, had no control group and most of its participants were taking conventional osteoporosis drugs before and during the trial, making it difficult to tease out the effects of the cell therapy.
What’s more, the researchers did not directly track the therapeutic cells in the recipients’ bodies, leaving a crucial question unanswered: did enough of the cells reach the bones to make a difference?
Straight to the bone
Robert Sackstein, a regenerative-medicine specialist at the Miami Veterans Affairs Medical Center in Florida and a co-author on the study, is confident that they did. Sackstein has spent decades studying how various cells with regenerative potential — including bone-forming progenitor cells known as mesenchymal stromal cells (MSCs) — can be steered through the body for maximal therapeutic effect.
MSCs, when injected into the bloodstream, cannot usually reach bone tissue. But in 2008, Sackstein and his colleagues found that adding a sugar called fucose to these stem cell-like cells enabled them to seek out and enter bones, leading to skeletal tissue generation in mice2.
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