New treatment reduces women’s osteoporosis fractures by 94%. A single infusion of patients’ own altered bone marrow cells dramatically reduced fractures in women with advanced osteoporosis.

One in three women over 50 will break a bone because of osteoporosis. Around the world, that adds up to about 10 million broken bones a year, roughly one every three seconds, according to the International Osteoporosis Foundation . Every pill and injection now available works by slowing the loss. None of them rebuilds a skeleton, and all of them must be taken for the rest of a woman’s life.

A new study describes something different. Ten women with advanced osteoporosis received a single infusion of their own bone marrow cells. In the two years that followed, broken bones across the group fell from eight a year to one every other year.

Bone isn’t a finished object. Two crews made up of specialized cells tear it down and rebuild it every day of a person’s life. One crew dissolves old bone. The other lays down new bone. In a healthy adult, the two stay in balance.

Menopause breaks the balance. The loss of estrogen lets the demolition crew outpace the builders. The spongy interior of the bone erodes first. What remains looks like a honeycomb with the walls worn thin. It carries weight until one ordinary movement asks slightly more of it than it can give.

Current medicines slow the demolition or nudge the builders along. They help. They also bring side effects that mount with every year of use. Close to a third of women who should be taking them are not, a gap that has widened for decades.

Repair Cells Without An Address

Bone marrow holds the cells that become bone builders. Those cells grow readily in a lab dish, which makes them an obvious candidate for treating a disease of too little bone. Earlier attempts to infuse them into the bloodstream went nowhere.

The reason turned out to be a matter of navigation. Blood vessels inside bone marrow have a kind of gate at their walls, and cells pass through only if they carry the right pass. Blood stem cells carry it naturally, which is why a bone marrow transplant works. Marrow repair cells do not. An infusion therefore sends them circling the body and past the bone that needs them.

The study solved that with sugar. The cells were only slightly modified by adding a sugar residue that lets them adhere to blood vessels, which stimulates bone growth. One missing sugar separates the cells that pass from those that don’t, and briefly treating the cells in a solution containing a natural enzyme and that single sugar completes the pattern. Nothing inside the cell is touched. No gene is edited. The added sugar wears off on its own within two days, which is long enough for the cells to reach bone and settle in.

The women were between 50 and 75, had all broken at least one bone and nearly all faced a high risk of breaking another. Marrow was drawn from the hip, grown into millions of cells over several weeks, treated with sugar and returned through a simple drip in the arm. Each woman went home the next day. None of the women had a reaction to the infusion. Across six years, none developed cancer, extra bone in the wrong places or any other unexpected condition.

In addition to dramatically reducing fractures, the treatment also improved bone density. Bone samples taken from the hip four months after the infusion held nearly twice as much bone tissue as samples taken the day of treatment. Detailed wrist scans at two years showed better internal bone structure. The women reported about a third less pain and noticeably less difficulty with daily movement.

A caveat is that the study included only 10 women. Nonetheless, the trial shows that the treatment has a dramatic effect over a six-year period. The cells came from older women with diseased marrow, the kind of cells long assumed to be too worn out to help, and they rebuilt bone anyway.

Infusion of slightly modified bone marrow stem cells may turn out to be useful in a variety of other diseases, including any condition involving tissue that would benefit from repair and regeneration.