Mayo Clinic: Researchers at Mayo Clinic’s campus in Florida have conducted the world’s first prospective, blinded and placebo-controlled clinical study to test the benefit of using bone marrow stem cells, a regenerative medicine therapy, to reduce arthritic pain and disability in knees. The researchers say such testing is needed because there are at least 600 stem cell clinics in the U.S. offering one form of stem cell therapy or another to an estimated 100,000-plus patients, who pay thousands of dollars, out of pocket, for the treatment, which has not undergone demanding clinical study. The findings in The American Journal of Sports Medicine include an anomalous finding — patients not only had a dramatic improvement in the knee that received stem cells, but also in their other knee, which also had painful arthritis but received only a saline control injection. Each of the 25 patients enrolled in the study had two bad knees, but did not know which knee received the stem cells.
Given that the stem cell-treated knee was no better than the
control-treated knee — both were significantly better than before the
study began — the researchers say the stem cells’ effectiveness remains
somewhat uninterpretable. They are only able to conclude the procedure
is safe to undergo as an option for knee pain, but they cannot yet
recommend it for routine arthritis care.
“Our findings can be interpreted in ways that we now need to test —
one of which is that bone marrow stem cell injection in one ailing knee
can relieve pain in both affected knees in a systemic or whole-body
fashion,” says the study’s lead author, Shane Shapiro, M.D., a Mayo Clinic orthopedic physician.
Journalists, sound bites with Dr. Shane Shapiro are available in the downloads below.
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“One hypothesis is that the stem cells we tested can home to areas of
injury where they are needed, which makes sense, given that stem cells
injected intravenously in cancer treatments end up in the patients’ bone
marrow where they need to go,” he says. “This is just a theory that can
explain our results, so it needs further testing.”
Another explanation is that merely injecting any substance into a knee offered relief from pain.
“That could be, but both this idea and the notion that a placebo
effect could be involved would be surprising, given that some patients
are still doing very well years after their study treatment ended,” says
He adds that these findings are important because while use of a
patient’s own stem cells for regenerative therapy is extraordinarily
popular, the treatments may be untested and are often poorly regulated.
Stem cell clinics often offer expensive treatments for conditions
that range from multiple sclerosis, lung and heart disease, to cosmetic
treatments, such as facelifts. None of these techniques have been
studied because clinics maintain that use of a patient’s own cells is
not a drug.
But, depending on how they are processed and used, stem cells can, in
fact, be regulated by the U.S. Food and Drug Administration as
biological products or drugs requiring rigorous safety and efficacy
approval processes. In early September, the FDA held scientific meetings
to clarify how to regulate such practices.
Mayo Clinic researchers developed their study with FDA approval.
“We feel that if we are going to offer any stem cell procedures to
our patients, the science needs to be worked out,” Dr. Shapiro says.
The study was conducted in Mayo’s Human Cell Therapy Lab. Researchers
extracted 60 to 90 milliliters of bone marrow from each patient, then
filtered it, removed all blood cells, and concentrated it down to 4 to 5
milliliters. The solution, which contained tens of thousands of stem
cells, was injected into a patient’s knee using ultrasound-guided
“We actually counted all of the stem cells with markers that are
accepted by the FDA, and we made sure they would be able to survive
inside the patient,” Dr. Shapiro says. “Counting is expensive. Most
clinics just draw the cells from bone marrow or fat and inject them back
into the patient without checking for stem cells, hoping that patients
get better,” he says.
Dr. Shapiro and his colleagues are currently designing new studies
that will test whether the stem cells home to distant areas of injuries,
as well as exploring other implications suggested in their findings.
Study investigators include Mayo Clinic in Florida senior author Mary
L. O’Connor, M.D., Shari E. Kazmerchak, Michael G. Heckman, and Abba C. Zubair, M.D., Ph.D. Dr. O’Connor is now at Yale University.
Funding for this study was from Mayo Clinic’s Center for Regenerative Medicine.