This is an excerpt from Second Opinion, a weekly roundup of eclectic and under-the-radar health and medical science news emailed to subscribers every Saturday morning. If you haven't subscribed yet, you can do that by clicking here.

Canada's direct-to-consumer cell therapy industry is thriving.

Across the country, private clinics continue to sell expensive procedures advertised as a form of "regenerative medicine."

The clinics use what they claim are stem cells that are siphoned from a patient's bone marrow or fat tissue and injected or given intravenously to treat a range of conditions including joint pain, multiple sclerosis and nerve disorders.

There is a lack of clinical trial evidence to determine whether the procedures are safe and effective. And there has been a long-running debate about whether they're legal.

This week Health Canada issued a public policy position on that point.

"All cell therapies are considered drugs under the Food and Drugs Act. This means that they must be authorized by Health Canada to ensure that they are safe and effective before they can be offered to Canadians," Health Canada said in a news release.

That policy statement confirms that cell therapies are not legal in Canada unless they've been formally approved as drugs, after going through a rigorous review. And so far Health Canada has not approved any of the direct-to-consumer treatments.

Health Canada also warned Canadians about potential safety risks.

"Unauthorized treatments have not been proven to be safe or effective and may cause life-threatening or life-altering risks, such as serious infections."

What happens next?

If these procedures are not approved, and might not be safe, are they still happening? The answer is yes.

Almost a dozen clinics across Canada confirmed to CBC News that they are still doing the procedures, with prices quoted as high as $15,000. Ten other clinics that advertised the procedures on their website could not be reached for comment.

Health Canada has been in touch with some of the clinics to inquire about their practice, but so far the agency has not taken any action to stop clinics from doing the autologous procedures. ("Autologous" means the patient's own cells or tissue are being used.)

That's puzzling to University of Minnesota researcher Leigh Turner, who provided his research notes to Health Canada months ago showing that there were 43 clinics in Canada doing the procedures. Turner's findings were published last September.

"It's like Health Canada is saying, 'We know these business aren't complying with Canadian law, and even in our latest document we're confirming that. Nonetheless, we're going to stand here on the sidelines with our hands in our pockets and not doing anything about it.' And that, to me, is the problem," Turner said.

"I don't understand why it's not more of a priority for Health Canada."

University of Minnesota researcher Leigh Turner says it's time for Health Canada to take meaningful action. (University of Nebraska)

Health Canada spokesperson André Gagnon told CBC News in an email that the agency is "currently working to bring clinics into compliance with the applicable regulatory framework."

"This will include requesting clinics to stop selling and advertising cell therapy products that do not meet the applicable requirements."

Health Canada did not indicate when it would take that action.

Turner said it's long overdue.

"We're talking about a nationwide phenomenon right now that has received national news coverage," he said. "There's a tremendous amount of empirical information. Health Canada has interacted with people willing to provide more information. Years have ticked by. That's enough time for Health Canada to take meaningful action."

One Alberta clinic announced on its website that it has officially stopped doing the procedures because they fall into a regulatory grey area.

"It was a decision we made and it was our decision alone," said Joe Burnham, regulatory manager at the Capri Clinic in Lacombe, Alta. The clinic performed about 1,500 procedures before deciding to stop in March. But patients are still calling.

"That's 80 per cent of our calls to this day. When are you guys up and running?"

Burnham said his clinic is investigating how to comply with Health Canada's regulations, but it's not yet clear how that can be done.

"Doctors that are doing procedures aren't drug companies. And the minute you call a procedure a drug, even if you have a regulatory right to, it turns doctors into drug manufacturers. That's the confusion," Burnham said.

Health Canada acknowledged that challenge, telling CBC News: "There is uncertainty surrounding the practical means of meeting federal product safety regulatory requirements for the sale of cell therapies that aren't mass produced, especially once initial clinical trials are completed.

"Health Canada is working to identify and overcome challenges specific to meeting regulatory requirements for the manufacturing and sale of autologous cell therapy products, including those prepared at the bedside."

They're not stem cells

Despite the claims from clinics that they are extracting stem cells, the clinics don't examine the fluid to determine what sorts of cells and other cellular products it contains.

And scientists point out that it is unlikely to contain true stem cells, which are cells that can transform into any tissue in the body. The extract from bone marrow and fat tissue contains another type of cells that were originally called "mesenchymal stem cells." But scientists now say that name is inaccurate and confusing.

In a commentary in Nature, with the title "Clear up this stem cell mess," Turner and some colleagues explained how the science has evolved since the cells in question were first described and named 25 years ago.

"They don't behave like stem cells," Michael Rudnicki, stem cell scientist at the Ottawa Hospital Research Institute, told CBC News last September when we first wrote about the name controversy. "None of the criteria we use to define stem cells are present in this population."

"There are clinical trials exploring their ability to modulate the immune system, but it's not a regenerative phenomenon," said Rudnicki, adding that most researchers in the scientific community have abandoned the term "mesenchymal stem cells" and instead call them "mesenchymal stromal cells."

By continuing to use the term "stem cell" for the fluid that is taken from a patient's bone marrow and fat, there is concern that patients will be misled into believing the therapies are able to regenerate bone and tissue, which has not been proven.

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