Teaching the World to Count: Does Your Doctor Know How to Dose Cells?
Yesterday I was meeting with the Interventional Orthopedics Foundation (IOF) scientific team. They showed me this great book that teaches physicians how to count the number of cells in a same-day stem cell treatment. I quickly realized that I was seeing a first in stem cells, a nonprofit organization that was dedicated to advancing the field and was willing to teach every physician who would listen how to up their game. As a result, I whipped out my phone and took a picture of this historic document.
Why Knowing Cell Dose Matters
If you’ve had a stem cell treatment or are planning on getting one, it’s almost a certainty (unless you saw a Regenexx network physician) that your doctor had no idea how many cells were being injected or if he or she did know the number, what that number meant. Think about that for a second and let it sink in. We have an entire new generation of physicians adopting stem cell treatments after taking weekend courses who have no idea how many stem cells they have available or how many should be injected. In no other area in medicine would that be remotely acceptable; in fact, in pretty much all areas, it would be considered really irresponsible.
Let’s take, for example, in vitro fertilization. Fertility specialists know if they have implanted a single embryo or five, as if they implant multiple embryos, the patient is more likely to end up pregnant, but she is also more likely to end up with twins, triplets, or more…In orthopedic stem cells, we do have several studies that suggest that dose is important. The largest orthopedic stem-cell-dosing study is one that we published on knee arthritis, where a minimum number of total cells was required to increase the likelihood of better pain improvement with a same-day stem cell procedure.
The Different Ways of Quantifying Stem Cell Number
- CFUs—Perhaps the oldest way of reporting the stem cell content of a treatment is CFUs, which stands for “colony-forming units.” This is a rough metric of the number of mesenchymal stem cells (MSCs) in a sample. You get to this count by placing some of the sample in culture and waiting for MSCs to form. The upside is that the measurement is easy to do without expensive lab equipment; the downside is that it’s, at best, an estimate as different lab techs can count the number of colonies differently. In fact, it’s recommended that several people count the number and then the average is used. In addition, only a percentage of cells form colonies, so the number you get doesn’t tie directly back to stem cell content. However, the biggest problem with CFUs is that since you need to incubate the sample and let it grow for days, you don’t have this number at the time you’re trying to make the decision about how to dose the patient.
- Flow Cytometry—The newest way to count stem cell number is called flow cytometry, also known as “flow.” A sample is used as above, but instead of growing it out, the cells are stained using fluorescent dyes with antibodies attached that target different markers on the surface of the cells. The dyed cells are then run through a machine that lines them up one by one and very quickly runs them through a laser counter. The upside of this method is that you can get a cell number fast enough to dose a patient. The downside is that these machines are expensive and, more importantly, notoriously hard to run and interpret. In addition, there is no one common cell-surface marker for an MSC; hence, several markers must be used, which provides only an estimate of stem cell number.
- TNC—TNC stands for “total nucleated cells.” This means the total number of all cells in a sample. Many physicians often confuse this number with stem cell number, so be cautious when you hear stem cell numbers being thrown around. In fact, in same day treatments, the stem cells are only a small percentage of the total cells in a sample regardless of whether we’re talking about bone marrow, fat, or any other tissue. The upside of TNC is that it’s quick and easy to obtain, as long as the doctor or technician follows certain rules. In addition, the TNC roughly follows stem cell percentage (i.e., samples with more total cells also tend also to have more stem cells). The downside is that this isn’t a direct stem cell count.
The IOF Wants to Teach the Stem Cell World How to Count!
The manual above is historic as no other organization has stepped forward to teach physicians and technicians how to reliably count the cell content of a stem cell sample being used in a patient. While many regenerative medicine conferences exist out there (almost all are for-profit ventures), I have never seen a physician nonprofit in this space take the lead on such a critical issue.
Reviewing the manual yesterday, it’s well written, easy to follow with copious illustrations, and idiot-proof at a physician level. While I don’t want to suggest that doctors are idiots, very, very few have any type of formal cell-biology training, so this book needed to be written at a level that nonexperts could readily understand. The scientists at IOF did a great job at finding that perfect educational level.
So how can your doctor learn to count? The IOF has courses it will be giving several times a year, teaching your doctor or his or her assistants how to accurately count cells. These courses will be taught by real stem cell scientists and will include hands-on experience with samples as well the use of many different commercial counting devices. Given that the IOF isn’t trying to sell anything to anybody, it will let the physicians decide which technologies they want to use.
The upshot? The book you see above represents a stem cell first—a nonprofit dedicated to upping the game of the tens of thousands of physicians who have taken a weekend course on how to use stem cells. Why does the IOF want to make sure that everyone begins to understand and measure dose? Because a world where the dose of every stem cell cocktail is known is one where physicians begin to understand how to maximize that dose by improving their stem-cell-harvest techniques. It’s also one where physicians can publish more research on how dose impacts outcome in different disorders. In short, it’s a better world than the one we live in now, where 99% of the time, the cell dose isn’t known or understood.