One of the most common questions we get asked at CIRM, almost every other day to be honest, is “are there any stem cell treatments for people with arthritis in their knees?” It’s not surprising. This is a problem that plagues millions of Americans and is one of the leading causes of disability in the US.

Sadly, we have to tell people that there are no stem cell treatments for osteoarthritis (OA) in the knee that have been approved by the Food and Drug Administration (FDA). There’s also a lack of solid evidence from clinical trials that the various approaches are effective.

But that could be changing. There’s a growing number of clinical trials underway looking at different approaches to treating OA in the knee using various forms of stem cells. Sixteen of those are listed at clinicaltrials.gov. And one new study suggests that just one injection of stem cells may be able to help reduce pain and inflammation in arthritic knees, at least for six months. The operative word here being may.

The study, published in the journal Stem Cells Translational Medicine,  used adipose-derived stromal cells, a kind of stem cell taken from the patient’s own fat. Previous studies have shown that these cells can have immune boosting and anti-scarring properties.

The cells were removed by liposuction, so not only did the patient’s get a boost for their knees they also got a little fat reduction. A nice bonus if desired.

The study was quite small. It involved 18 patients, between the ages of 50 and 75, all of whom had suffered from osteoarthritis (OA) in the knee for at least a year before the treatment. This condition is caused by the cartilage in the knee breaking down, allowing bones to rub against each other, leading to pain, stiffness and swelling.

One group of patients were given a low dose of the cells (23,000) injected directly into the knee, one a medium dose (103,000) and one a high dose (503,000).

Over the next six months, the patients were closely followed to see if there were any side effects and, of course, any improvement in their condition. In a news release, Christian Jorgensen, of University Hospital of Montpellier, the director of the study, said the results were encouraging:

“Although this phase I study included a limited number of patients without a placebo arm we were able to show that this innovative treatment was well tolerated in patients with knee OA and it provided encouraging preliminary evidence of efficacy. Interestingly, patients treated with low-dose ASCs significantly improved in pain and function compared with the baseline.”

The researchers caution that the treatment doesn’t halt the progression of OA and does not restore the damaged cartilage, instead it seems to help patients by reducing inflammation.

In a news article about the study Tony Atala, director of the Wake Forest Institute for Regenerative Medicine, in Winston-Salem, N.C. and the editor of Stem Cells Translational Medicine said the study offered the patients involved another benefit:

“In fact, most of the patients (in the study group) who had previously scheduled total knee replacement surgery decided to cancel the surgery. It will be interesting to see if these improvements are seen in larger groups of study participants.”

Interesting is an understatement.

But while this is encouraging it’s important to remember it was done in a small group of patients and needs to be replicated in a much larger group before we can draw any solid conclusions. It will also be important to see if the benefits last longer than six months.

We might not have to wait too long for some answers. The researchers are already running a 2-year trial involving 150 people in Europe.

We’ll let you know what they find.