Here’s some spine-tingling news.
New research suggests a drug already available on pharmacy shelves could help ease chronic lower back pain.
It’s a welcome discovery for the millions of Americans who live with persistent discomfort, which can make everyday tasks like walking, sleeping or working feel like a constant struggle.
Yet, despite being the leading cause of disability worldwide, many people with lower back pain suffer in silence, unable to find relief.
That’s partly because doctors often can’t pinpoint a clear structural cause, so long-term treatment becomes a frustrating game of trial and error.
But the tide may be turning.
In a new study, researchers found that treatment with parathyroid hormone (PTH) may ease chronic lower back pain by limiting abnormal nerve growth inside damaged spinal tissue.
“During spinal degeneration, pain-sensing nerves grow into regions where they normally do not exist,” Dr. Janet L. Crane, a faculty member of Johns Hopkins’ Center for Musculoskeletal Research and one of the study’s authors, said in a statement.
“Our findings show that parathyroid hormone can reverse this process by activating natural signals that push these nerves away,” she explained.
In the body, PTH is naturally produced by the parathyroid glands and helps regulate calcium levels and bone remodeling.
Synthetic versions are already used to treat osteoporosis, a bone-thinning disease that leaves sufferers brittle and weak.
And while previous studies hinted that these treatments could also reduce bone-related pain, the reason why remained a mystery.
To find out, Crane and her colleagues ran three mouse experiments that mirrored common causes of spinal degeneration: aging, mechanical instability from surgery and genetic susceptibility.
The mice got daily PTH injections for two weeks to two months, while control groups received inactive solutions.
Researchers then examined their spinal tissue with high-resolution imaging and tested the mice’s sensitivity to pressure, heat and movement.
After one to two months, the mice treated with PTH showed stronger and healthier spinal tissue. The thin layers that separate the spinal discs from the bones became less porous and more stable, helping their spines hold up better.
At the same time, treated mice tolerated pressure better, withdrew more slowly from heat and were more active than the mice who weren’t given PTH.
The research team also studied the nerve fibers inside the mice’s spines because, when the spine is damaged, pain nerves can grow where they shouldn’t, making the area more sensitive and uncomfortable.
They discovered that PTH treatment reduced the number of these nerve fibers. It works by prompting bone-building cells to make a protein called Slit3, which guides the nerves away from sensitive areas.
Further lab testing showed that when nerve cells were exposed to Slit3 in a dish, their extensions became shorter and less invasive.
While the study was done in animals, researchers say the results could help explain why some osteoporosis patients on PTH-based treatments report experiencing less back pain.
Still, they stressed that human trials are needed before doctors can start prescribing PTH specifically for chronic lower back pain relief.
The good news? Since the hormone therapy is already approved in the US for other conditions, it could move to human testing faster.
That’s important, because the demand for effective treatments is only expected to grow.
In 2020, lower back pain affected 619 million people worldwide — a number that is projected to rise to 843 million by 2050, driven largely by population growth and aging.
The consequences are wide reaching. A US survey of people living with chronic lower back pain found that 63% said it interfered with their ability to exercise and stand, 58% said it affected their ability to walk and 55% said it made getting a good night’s sleep difficult.
Chronic lower back pain has also been linked to anxiety and stress, lower overall happiness, reduced participation in daily life and missed school and workdays.
