Knoepfler Lab Stem Cell Blog
Building stem cell bridges to advance cures
Stem cells grown in culture are a drug.
Agree or disagree?
I believe it is a correct statement. I don’t think it is even a question any more as it was a few months ago.
Yes, I am convinced that the FDA, as supported by a recent federal court ruling, has it right that growing stem cells in culture yields biological drugs.
Such growth makes stem cells fundamentally different than the endogenous stem cells that exist in our bodies.
In fact not just me, but more broadly stem cell biologists largely concur that growing stem cells in culture substantially increases the risks associated with their potential clinical use.
So why even grow them?
Of all the wonderful properties of stem cells, there is one not so great property that most often goes without saying.
They are very rare.
It is hard to get many true stem cells from the human body so most clinics resort to growing the stem cells prior to use. In this way clinics may boost say 1 million cells into 1 billion cells, which they then transplant. By analogy compare taking a tiny fragment of an aspirin (1/1000th of a full aspirin) versus a full aspirin….of course the whole aspirin will be more powerful. The same idea applies to potential stem cell therapies–1,000x as many cells should be more powerful. Of course with increased power also comes increased risk of side effects.
For sake of argument, let’s say for the moment that we’re going to grow the stem cells to be used for transplant, what happens during this growth process?
The growth-related events are critically important for anyone who cares about stem cells to fully understand.
Sadly it seems the dubious clinics and their supporters either don’t understand this or intentionally sweep it under the rug…or should I say under the gurney.
Why should you believe what I say?
I’ve been growing and studying cells more than 2 decades.
When you grow cells in a lab they change. They can become something quite different than what you started with.
How do they change?
During cell growth in culture in labs, a rapid form of cellular evolution happens.
You don’t even have to believe in human evolution to understand the sense and logic in cellular evolution.
When you grow cells, over time the cells that grow the fastest will inevitably produce progeny that end up taking over the population.
These fast cells grow so much more quickly that they are greatly over-represented in the cell population at the end.
These winners of the cellular evolutionary process that happens during growth in culture even over a relatively short period of time typically share one thing in common.
They become more and more like cancer cells.
A second fact is that with every day that passes during growth, cells tend to acquire more and more mutations as well in their genomes. Thus, the normal genomic sequence of the freshly harvest stem cells from a human patient may be significantly different than the genomic sequence of the cells after growth, which often is abnormal.
As fate would have it the prevalence of mutations increases over time in culture for another reason and that is that some mutations make cells grow faster than their neighboring cells. As a result, mutant cells are often the winners of the cellular evolution that happens during culture described above.
Cells grown in culture are also exposed to a large number of foreign substances during growth that may make the cells more dangerous should they subsequently be transplanted. These substances can range from potentially hazardous chemicals such as endotoxins (terrifically poisonous chemicals made by bacteria) to contaminating proteins that ride piggyback on cells into patients.
Of course not all of this bad stuff always will happen.
But it will happen often enough that growth in culture requires additional validation and safety testing that to my knowledge dubious stem cell clinics never perform prior to transplant into patients. The clinics are either ignorant of these facts of cell biology or they are cutting corners to save themselves money.
I don’t believe in banning growth of cells in culture prior to transplant. Not at all. I believe, however, that it necessitates a higher level of caution by clinics and patients and also more regulatory scrutiny by the FDA.
The mission of the Knoepfler Lab here at UC Davis School of Medicine is to advance knowledge and cures. We aim to speed development of stem cell treatments for Cancer, Alzheimer’s Disease, Stroke, Parkinson’s Disease, Heart Attack, Spinal Cord Injury, and others. We fight anti-stem cell propaganda and have the only stem cell podcast in the world. Discussions range from hard core science to stem cell drugs development to stem cell videos to stem cells as sports performance enhancing drugs to biotech stocks to NIH and CIRM funding to the politics of research including Obama and Republicans. We also have stem cell job postings and consult with biotech companies. We do our science here in California, but we are global and are currently the only stem cell blog in the world written by a faculty level scientist, Paul Knoepfler.