Does Stem Cell Therapy Actually Work?

Credit: Photograph by Shana Novak

New York City integrative physician David Borenstein flips through his appointment book and ticks off recent conditions he's treated: chronic obstructive pulmonary disease; Parkinson's; Crohn's disease; Lyme disease; cardiomyopathy; stroke; lower back, knee, and hip pain.

It would appear that Borenstein is the world's most versatile medical practitioner. But he's a specialist in rehabilitative medicine, not a miracle worker. The incredible list of maladies on his treatment menu is the result of his having joined the Cell Surgical Network (CSN). The 147 physicians in the group believe they can treat and likely ameliorate almost any degenerative disease simply by taking stem cells extracted from a patient's fat and injecting them back into his bloodstream. And in that belief, they're certainly not alone. In the past five years, the number of U.S. stem cell clinics has mushroomed from 25 to 570, according to a recent report published in the journal Cell Stem Cell.

While it's still unclear exactly how stem cells work, accumulating data suggests that they're an effective way to treat joint pain and injury — arthritic knees, torn ACLs and rotator cuffs, and more. Anecdotal evidence indicates cells can do far more, helping to revive stroke victims and even mobilize the paralyzed. But the costly procedures are still unapproved by the FDA, leaving an open gate for medical charlatans and hucksters.

Back in Borenstein's office, I ask the doctor how he thinks stem cells work. He uses the analogy of a gold mine. "There's tons of gold in there," he says, pointing to my body. "The problem is, it's sitting in the ground, doing nothing. You gotta go in there and get it."

He leads me to his tiny treatment room across the hall. Cueing a step-by-step video, Borenstein shows how he makes a small incision in one side of a patient's torso to insert a cannula, a foot-long hollow metal needle that's attached to a thick 50cc syringe. From there the cannula is moved vigorously around to break up fat tissue, and then the hot-pink and yellowish sludge is sucked into the syringe — basically a mini-liposuction procedure. Next, he separates the sludge in a small centrifuge, adds an enzyme to break down the fat, and incubates what's left for 30 minutes: All of this liberates stem cells as well as proteins called cytokines, a "magic soup" that can promote healing. After filtering and washing rituals, he loads about 10cc of this stuff into an IV bag, to be delivered into a vein in the patient's arm. At which point, he says, the cells will seek out and treat whatever ails you.

Let's be clear, we are not talking about embryonic stem cells here. Embryonic stem cells have been dogged by ethical controversy and the enmity of right-to-lifers — you must destroy a stored human embryo to extract the cells. The more exciting development during the past decade is the discovery that our own adult stem cells have a lot more therapeutic potential than we had ever guessed.

We all have cells in our blood, gut, skin, and fat that get old, die, and need to be replaced with new cells. Our stem cells divide as much as needed to repair and replace them. Theoretically, the younger you are, the younger your stem cells and the better they do their job. Decades ago, researchers discovered that a particular type of stem cell — mesenchymal stem cells — in bone marrow could generate new bone, cartilage, and fat. In 2001 researchers discovered that mesenchymal cells are even more plentiful in body fat.

But what happens if you extract those mesenchymal cells from bone or fat and put them back in the body? We're not really sure. The best current thinking is that injected stem cells exert a powerful healing effect, secreting proteins that improve blood flow, tamp inflammation, and aid in recovery, says Stanford neurosurgeon and stem cell researcher Gary Steinberg. That's whether you inject them straight into an arthritic knee to help generate new cartilage, or into the bloodstream to possibly restore Parkinson's-damaged nerves. How do the stem cells know exactly where to go and what to do? CSN co-founder and Palm Springs urologist Elliot Lander likens the process to a beacon. Injured and inflamed cells send out an SOS signal; new stem cells pick it up. "The stem cells are so smart, all you have to do is turn them loose," he offers. "They float around to different areas of the body and fix them."

The promise of stem cells is nothing new — academics have been studying them in animal models and human trials for more than 20 years. But starting in the last decade, clinical stem cell pioneers like Dr. Christopher Centeno, the founder of the Colorado-headquartered Regenexx (working with bone marrow) and Lander (working with fat) began taking the cells out of the lab and putting them into patients for money — anywhere from $4,000 to $12,000 per procedure — for investigational therapies that insurance wouldn't cover. The early adopters have streamlined the extracting and delivery technology and license it to doctors to expand the field. And to almost everyone's surprise, the FDA has stayed on the sidelines, allowing stem cell clinics to grow into a kind of parallel universe operating outside the traditional institutions that have controlled biomedical progress — the National Institutes of Health, major research universities, Big Pharma.

Whether this is a good thing depends on where you sit. Academics are mostly aghast. To their minds, research hasn't adequately established safety or efficacy. "There's a long history of individuals entering the [medical] marketplace and offering some cure-all panacea," says University of Minnesota bioethicist Leigh Turner, who co-authored the new report criticizing the proliferation of stem cell clinics. "The problem is, those claims typically aren't true." (Recall shark cartilage and, before that, laetrile as can't-miss cancer cures.) For his part Lander says he and his CSN co-founding partner, cosmetic surgeon Mark Berman, are doing what's necessary to advance this new therapy. "We take things and try them, and if they work, we do it again. If they don't, we don't do it anymore — true trial and error." That may not sound reassuring, but it's how the field of surgery continues to advance — and Lander considers stem cell therapy just another form of surgery.

Stem cell clinicians will admit they don't have the broad, controlled studies to prove injected stem cells are safe and effective. That's a tall order without government or Big Pharma funding. "I will gladly do the largest double-blind, placebo-controlled study of all time if you give me the money," says Kristin Comella, chief science officer of U.S. Stem Cells, a Florida-based company that has given some 600 doctors stem cell training. What clinicians do have is what they've seen with their own eyes. "We literally have patients who have come out of wheelchairs and are walking again," Comella says.

That's exactly what happened in a recent study by Steinberg's Stanford team, when a stroke victim rose from her wheelchair after mesenchymal stem cells were injected directly into her brain. "She was two years out from a stroke and could barely lift her left leg," Steinberg says. "Now she's walking." Half of the study's 18 subjects experienced a "clinically meaningful recovery," he says, despite the fact that most had been crippled by stroke for at least a year. That's beyond the point doctors look for improvement — when the damaged brain circuits are thought to be dead for good.

Despite these miraculous-sounding results, Steinberg still believes that stem cell treatments should remain the province of academic research until we better understand how, or whether, to use them. Of course, as an academic, that's what he would say. But that doesn't mean he's wrong. Check out the stem cell–patient medical blogs and you'll find a significant number of unhappy people who've paid thousands of dollars at clinics and have not seen any results. 


Set aside the tantalizing glimpses of Lazarus patients, and the surest stem cell bet is still the joints. That's where the three horsemen of physical deterioration — tissue damage, inflammation, and autoimmunity — come together in a contained space. News of elite athletes' orthopedic stem cell operations has trickled out for years, suggesting the weekend athlete might benefit, too.

Chad Rivera felt those orthopedic benefits despite originally having a stem cell procedure for his vision, most of which he'd lost in his early twenties due to a rare eye disease. The 49-year-old has had three stem cell injections with the Lander-Berman team and says he's noticed "baby step" improvements in his sight. What's been more apparent, he says, is the lift he feels after each treatment — a "rejuvenation," he calls it — and less pain and better movement in muscles and joints, which have taken a beating from years of martial arts and skateboarding. Listening to Rivera, you realize that his experience straddles a thin line between qualified success and placebo effect.

A more clear-cut success story is Eddy Beltran's. Last year the 45-year-old attorney from Irvine, California, tore his ACL during a pickup basketball game. "Two orthopedists said if I wanted to go back to basketball, surgery was the only way," Beltran recalls. Instead he received a bone-marrow stem cell injection at Centeno's clinic in Broomfield, Colorado. Three months after the procedure, the tear had healed. Now, he says, "I can jump, run hard, and I'm about back to normal."

You won't find Dr. Laith Jazrawi, the director of the NYU Langone sports medicine division, surprised by results like these. To answer stem cell critics, he points to recent well-conducted trials in which patients who received knee arthroscopy and a stem cell injection experienced less pain and better outcomes, two years postsurgery, than patients who had the arthroscopy alone. And in a recently published study by Centeno, no major safety issues turned up in more than 2,000 patients.

But Jazrawi doesn't offer stem cell treatments to orthopedic patients immediately. "If I knew the stem cells were a permanent solution, I'd be more aggressive about using this as a first-line treatment," he says. "But my fear is that I'm charging for pain relief that might go away in a year." In theory, multiple injections may keep the pain at bay indefinitely. But we're talking about costs as high as $12,000 a procedure, driven up by expensive equipment and extra malpractice insurance.

Jazrawi's tune changes for patients who have had the usual first-line therapies for chronic joint pain — injections with cortisone or hyaluronic acid — and they're still in distress. His textbook stem cell patients are young or middle-aged men who have damaged their knees playing sports and now have degenerative cartilage or osteoarthritis. "More than likely they're going to need a joint replacement," he says. "But if they get it now, they won't be able to be as active and they won't be happy." Out of the hundred guys in this group that Jazrawi has treated with stem cells, half said they were extremely pleased with the decrease in pain and increase in function. "These are patients for whom we didn't have a good answer," he says. "Stem cells may be that answer."

Whatever you make of for-profit stem cell clinics, it seems a good bet that the therapy, in some iteration, will be part of the future of medicine. How that future will manifest is anyone's guess. Clinics, along with the blue-sky vision they promote, may continue to proliferate to the point where young, healthy people start banking stem cells for future use. (This is happening on a limited scale now, an option that runs as little as $2,500.) Years later, when those people become vulnerable to disease, they can have their youthful cells injected back into their bodies to repair damage with the vigor of their younger selves. Or it may be that Big Pharma succeeds in mass-culturing stem cells into a commercially viable product. In this scenario, you might buy stem cells at the pharmacy and take them for a specific problem. Stem cells could also be bioengineered as a synthetic product, the way insulin and thyroid hormone are now. No matter how it shakes out, the future will be, medically speaking, a better place.

How? Let's take one example — joint replacement — which the orthopedic world regards as a crowning achievement. Aging boomers en masse are currently in the process of acquiring new knees and hips, draining billions from the health care system and experiencing pain, suffering, even in some cases death. Orthopedic stem cell treatments, if early results are confirmed, could slash the need for those surgeries.

For today, however, we remain in murky medical waters. Stem cells are a high-priced treatment backed by insufficient research, and they can be administered by any physician willing to take a weekend course and accept cash or charge. Still, Florida stem cell scientist Comella, a true believer who gets stem cell injections every six to 12 months as a just-in-case measure, is defiant: "I don't know if I should be offended or happy when people call what we're doing the Wild West," she says. "Nothing was invented by someone just following the rules."


Stem Cell Shopping: What to Know

Academics caution against for-profit stem cell clinics. Instead, try to get into a university clinical trial in which no money changes hands. If that's not an option, remember these tips.

1. Check credentials.

Most providers weren't delivering stem cells even five years ago. So make sure to look for mainstream medical bona fides, degrees, hospital affiliations, and referrals from other doctors.

2. Avoid the hard sell.

"Guaranteed" results, aggressive advertising, patient testimonials, up-sells of expensive complementary therapies, nondisclosure agreements that restrain you from discussing negative experiences — these are all red flags.

3. Involve a specialist.

If you have, for example, a neurological condition, you want a neurologist to interpret symptoms, whether or not he's involved in your stem cell treatments. If the cells don't work, a nonspecialist at a stem cell clinic will have nothing more to offer.