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A stem cell treatment could finally bring relief to millions of people with chronic lower back pain. If it works, the injection could become a crucial tool for curbing the opioid epidemic currently killing thousands in the US.
Overdoses from prescription opioids have quadrupled since 1999, and opioids accounted for 33,000 deaths in 2015 alone. Many of those deaths occur as a result of people becoming addicted to opioids after being prescribed drugs such as oxycodone, hydrocodone or methadone to relieve lower back pain. It is a common health issue that affects around 28 million people in the US and accounts for around half of all opioid painkiller prescriptions there.
Stem cells might change that. Injected into damaged discs between the vertebrae of the spine, each dose contains around 6 million cells. Called mesenchymal precursor cells, they dampen down inflammation and secrete factors that help rebuild damaged tissue. In experiments in sheep, these cells completely rebuilt damaged vertebral discs, prompting Silviu Itescu of the firm Mesoblast in Melbourne, Australia, and his team to try the technique in people.
“In 100 patients, we’ve shown substantial improvements in function and pain relief that last two years or more,” says Itescu. MRI scans found that the cells seemed to rebuild damaged discs in people too. “If we’re successful in [our] larger trial currently under way, we can hopefully keep people away from opioids,” says Itescu.
Encouraging results
The cells are being tested specifically for treating degenerative disc disease, which accounts for around 22 per cent of cases of chronic lower back pain. The discs between our vertebrae act as shock absorbers, but they can dry out through wear and tear or ageing. This causes them to shrink, reducing their cushioning power, and potentially leading to trapped nerves. Disc injury can also trigger inflammation that further aggravates the condition.
One injection of the cells was enough to help around half of those treated to experience no back pain for two years. Some participants have now been free of pain for three years.
Almost half of those treated became more mobile, dropping 15 points on a 100-point “disability” scale. Fewer than 13 per cent of the control group, who received a salt-water injection, showed the same improvement.
The company presented these preliminary results at the annual meeting of the US Spine Intervention Society in New Orleans in August, and will give more detail at the Piper Jaffray Healthcare Conference in New York in November.
Itescu’s company extracts the stem cells from the bone marrow of donors, and then grows them in the lab to create large amounts for treating many people. Unlike many cells, Itescu says donated mesenchymal precursor cells aren’t recognised by a recipient’s immune system, meaning that someone who receives the treatment does not need to take immunosuppressant drugs.
When in place, the cells reinflate vertebral discs that have dried out and cracked, losing their strength, says Itescu. They do this by causing water to be trapped in the discs, “almost like pumping up a tyre,” he says.
The rationale makes sense, says David Thomas, of the opioid and pain working group at the US National Institute on Drug Abuse in Bethesda, Maryland. He says that other teams are developing promising treatments intended to lower the inflammation of painful discs.
Opioid emergency
In August, President Trump said he intends to declare the US opioid crisis a national emergency and he is expected to officially do so this week. But the opioid problem is not restricted to the US, and there are fears that a similar painkiller addiction epidemic is under way in the UK. Codeine-related deaths have more than doubled in Australia since 2000, prompting the country to ban over-the-counter sales of the painkiller from February 2018.
New treatments for back pain will be important for fighting this, but Caleb Alexander of the Johns Hopkins Center for Drugs Safety and Effectiveness in Maryland says existing alternatives to opioids – such as non-steroidal anti-inflammatory drugs and physical therapy – have more immediate potential for alleviating the epidemic.
“Any practical application of these types of treatments is a long way off, and there are countless reasons why these promising early results may not translate into tomorrow’s cures,” warns Alexander.
But Thomas says existing treatments for back pain often fail or are only minimally effective. “We really do need better treatments for lower back pain, so this is encouraging,” he says. “But we need to see how it works out.”