In recent weeks, Thomas Einhorn, M.D., has become a stem cell savior, a doctor who is showing there’s no need to go down the embryonic stem cell road full of political landmines. In fact, he’s being touted as a reason why debate on the issue is not even needed since adult stem cells appear to be working just fine for his patients, thank you very much.
“Adult stem cell studies far ahead of embryonic research” and “Adult stem cell research leaving embryos behind” are just a few of the headlines to hit the street this month in relation to Einhorn’s work. But behind the sound bites are some exciting prospects and progress from Einhorn’s work.
For his part, Einhorn is a rather down-to-earth researcher who makes no claims of solving any stem cell dilemmas. Instead he offers up his experience as another step in a process that he has learned from his predecessors and emphasizes the need for proper patient selection in order to obtain the best results.
The Man Behind the Headlines
Thomas Einhorn, M, D., is the Chairman of the Department of Orthopaedic Surgery at Boston University and Professor of Orthopaedic Surgery, Biochemistry and Biomedical Engineering there as well. He’s a graduate of Rutgers and Cornell Medical and completed his internship at UPenn before an orthopedic residency at St. Luke’s-Roosevelt Hospital in New York City.
Thomas Einhorn, M.D.
Boston University School of MedicineBesides bone and cartilage regeneration, Einhorn also focuses his efforts on reconstructive surgery of hips and knees and treating metabolic bone disease.
He is the past Chairman of the Orthopaedics and Musculoskeletal Study Section of the National Institutes of Health, President of the Orthopaedic Research Society, President of the International Society for Fracture Repair and Chairman for two American Academy of Orthopaedic Surgeons committees: Examinations and the Council on Research and Scientific Affairs. Today, he is on the Board of Trustees of the Orthopaedic Research and Education Foundation and the National Osteoporosis Foundation.
Einhorn’s career distinctions include publishing over 200 peer-reviewed articles and being presented with numerous awards including the Marshall R. Urist Award and the Alfred R. Shands, Jr. Award from the Orthopaedic Research Society.
Avascular Necrosis of the Hip
The specialty that is getting Einhorn press these days is his orthopedic adult stem cell surgery for avascular necrosis (AVN) of the hip.
Femural head with avascular necrosis/Creative CommonsUnlike other hip conditions, AVN’s demographic is both significantly younger and broader. Most AVN patients are between 20 years to 60 years old. For these and other reasons, these patients are simply not the best candidates for hip replacements. Patients under 50 are far more active than their older counterparts and total hip replacement surgery both limits physical activity and also poses the need for revisions should the hip replacement wore out of many years of high use—as, of course, most do. Enter Dr. Einhorn’s autologous stem cell therapy and the makings for a new and potentially more age-appropriate solution may be emerging.
Stem Cells to the Rescue
Einhorn has been working on this process for more than two years. His initial goal was to slow down the progression of AVN but as he conducted his experiments he found that the procedure appeared to regenerate bone in the femoral head. Of course, many researchers have documented the ability of autologous bone marrow stem cells to regenerate bone in several animal and some human models. But there is no substitute for seeing it yourself.
Einhorn’s technique is to draw bone marrow from a patient’s pelvis, concentrate it (8 ounces of bone marrow become 20 cc) and then re-inject the marrow concentrate with approximately 20 mm cells (using a specially designed drill Einhorn himself invented) into the dying bone in the hip.
Several aspects of Einhorn’s autologous process and approach stand out. “In particular I was drawn to work I heard about what was going on in Paris and Brussels where they were taking patients’ bone marrow, concentrating it, and re-injecting it. So I traveled to Paris and learned from Dr. Philippe Hernigou [of the Hôpital Henri Mondor]. He took a patient with avascular necrosis and that is where it all began for me, ” explains Einhorn.
“Bone marrow contains many different types of cells, and they interact with each other under normal conditions. So the concept of concentration with these cells accompanied by their friends so to speak that they work with all the time, means the creation of super bone marrow. This type of graft makes more sense to me than harvesting bone marrow and isolating the MSCs [mesenchymal stem cells]. You might also have endothelial cells. So I decided I was going to adopt the technique I learned in Paris.”
The working theory is that concentrated cells and “their friends” will interact with each other and the surrounding environment in the avascular femoral head and stimulate new capillary and blood vessel growth while also recruiting and differentiating into new bone tissue. So in theory and perhaps (to be studied further) in fact, the therapy solves the two most critical problems associated with AVN—specifically, restoration of blood flow which led to the necrosis in the first place and restoration if not regeneration of lost bone. Einhorn adds that the necrosed tissue is actually useful as a scaffold for new osteoclasts and osteoblasts. He says the patients he’s treated have been able to experience swift recoveries of about a week for full weight bearing and six months to return to vigorous physical activity.
Einhorn’s patients are extolling their recoveries and some have gone from being wheelchair bound to playing soccer and bike riding.
Patient Selection
Very few physicians have attempted this type of approach to treating AVN. But Einhorn and Hernigou, two very well respected researcher/scientists/surgeons lend important credibility to this approach. Since Einhorn started treating AVN patients, the word has circulated in the patient community and he has received a barrage of patient requests. According to Dr. Einhorn, patient selectivity is so important. Specifically, success rates for this procedure are highest during the earliest stages of the disease.
“I have used the technique on 60 patients. With the Internet, people can be very resourceful about their health care and they will come to you. I believe in carefully selected patients and that is why I have an 85% success rate, ” explains Einhorn. “After two years we have gotten very efficient with our assessment process. Our protocol is to use assessment tools that are quantitative, such as MRIs. We use a radiographically based scale that has five categories that describe the condition of the femoral head.”
Patients with categories 1 (has no symptoms, nothing on X-ray, but MRI shows damage) and 2 (femoral head not collapsed, some symptoms and MRI consistent with AVN) make for the best candidates.
“Once the hip has seen some collapse it will probably not work, so we have a very automated system of just looking at X-rays and MRIs to determine if someone is a good candidate, ” adds Einhorn.
He is also currently working with two knee patients, but he tells OTW it is too early to tell whether this same concept will apply to the knee joint as well.
Looking Ahead
Soon the orthopedic community will have some hard numbers to digest from Einhorn. He is currently working on a four-year prospective case series study that began enrolling patients last year. The study is designed to provide organized and peer-reviewed clinical results of those patients who have received concentrated bone marrow aspirate to treat AVN.
As far as what the success of this procedure means for the device market, Einhorn believes regenerative medicine is the natural evolution. He says stem cell therapy could eventually eliminate the need for joint replacement. He says the orthopedic community is embracing this concept more every day.
Einhorn’s technique, known as Bone Marrow Aspirate Concentration (BMAC), is to draw bone marrow from a patient’s pelvis, concentrate it (eight ounces of bone marrow become 20 cc) and then re-inject the marrow concentrate with approximately 20mm cells (using a specially designed drill Einhorn himself invented) into the dying bone in the hip.
“I haven’t done a lot to promote non-union fractures, ” says Einhorn. “I did one case referred to me by the Massachusetts General Hospital of this badly fractured ankle that only partially healed. After being asked if I could try treating the patient, we did and three months later it was completely healed.”
NeoStem
Industry is taking notice of Einhorn’s success. Last week, international biopharmaceutical company, NeoStem, Inc. (NYSE Amex: NBS) named him to its Medical Advisory Board. The plan appears to utilize Einhorn’s stem cell knowledge in the development of applications of adult stem cells for orthopedic injuries. That’s in addition to working on applications for NeoStem’s VSEL Technology for the orthopedic community. VSEL Technology uses tiny adult stem cells that appear to mimic the beneficial properties of embryonic stem cells. And NeoStem just happens to be the worldwide license holder for this technology.
There’s little doubt with so much on the stem cell horizon that we will get to revisit Dr. Einhorn’s progress and enjoy some hard data from his lab in the hopefully near future.
