There are No Mesenchymal Stem Cells

A growing number of researchers are arguing that the term "mesenchymal stem cell" has broadened to the point of uselessness, and now serves to obscure significant differences in cell populations. This is a similar situation to that of the long-running discussion regarding very small embryonic-like stem cells, another term of art that probably lumps together a broad selection of quite different cell types. Since mesenchymal stem cells, whatever they might be in each individual case, are now widely used in therapy it seems a little more pressing to resolve questions of cell identity here, however. To what degree are varied results from treatments an outcome of failing to adequately categorize cell phenotypes and sources? Mesenchymal stem cell transplantation is a reliable way to reduce chronic inflammation, but any other outcome, such as some degree of tissue regeneration, is by no means assured.

Various populations of cells in the adult human body have been the subject of controversy since the early 2000s. Contradictory findings about these haphazardly termed 'mesenchymal stem cells', including their origins, developmental potential, biological functions and possible therapeutic uses, have prompted biologists, clinicians and scientific societies to recommend that the term be revised or abandoned. Last year, even the author of the paper that first used the term mesenchymal stem cells (MSCs) called for a name change.

Tissue-specific stem cells, which have a limited ability to turn into other cell types, are the norm in most of the adult body. Several studies indicate that the variety of cells currently dropped into the MSC bucket will turn out to be various tissue-specific cell types, including stem cells. Yet the name persists despite the evidence pointing to this, and almost two decades after questions about the validity of MSCs were first raised. A literature search indicates that, over the past 5 years, more than 3,000 research articles referring to MSCs have been published every year.

In our view, the wildly varying reports have helped MSCs to acquire a near-magical, all-things-to-all-people quality in the media and in the public mind - hype that has been easy to exploit. MSCs have become the go-to cell type for many unproven stem-cell interventions. The confusion must be cleared up. What is needed is a coordinated global effort to improve understanding of the biology of the cells currently termed MSCs, and a commitment from researchers, journal editors, and others to use more precise labels. We must develop standardized analyses of gene expression, including on a cell-by-cell basis, and rigorous assays to establish the precise products of cell differentiation in various tissues. Such efforts could put an end to lingering questions about MSC identity and function, once and for all.



I found an article at Longevity Letters that is titled: What pregnancy taught me about aging. I have asked the audience here questions about if they want to have children and if, then why? In the article she writes about that most people concerned about life extension don't have children and few who have children and few females are within the life extension movement:

Maybe one of the keys to expand the field is to get those groups involved. Sinclair has children and he cares about their longevity by giving them resveratrol, etc. All parents should be involved.

Posted by: Norse at October 1st, 2018 7:22 AM

Caplan has been recommending suggesting a change to Medicinal Signaling Cells for about five years. Beyond that I must admit having fuzzy understanding of what MSCs precisely do, despite having had multiple MSC treatments

Posted by: JohnD at October 1st, 2018 9:57 AM

That very few women have interest in anti-aging longevity has always been a mystery to me. Women spend inordinate amounts of money and time on cosmetics, cosmetic procedures, and fitness in order to maintain "youthful" looks. Obviously they want to maintain their SMV (sexual market value). Yet they have no interest in biotechnological life extension. Perhaps this is because they think its still an SF fantasy and thus a "nerdly" thing rather than something real and doable.

Any thoughts?

Posted by: Abelard Lindsey at October 1st, 2018 10:30 AM

@Abelard Lindsey

That, and also the most prominent anti aging faces are to nerdy and , let's face it, unappealingt to most to women. They just don't have that charisma .

On the other hand, Even with a glimmer of hope many women would undergo the treatments in a blink of the eye. There's a reason there are so many questionable stem cells clinics. It requires quite a leap and a courage to accept that this is not just a pipe dream. Our coping mechanisms are not allowing us to raise the hopes to much. For millennia it has been given that the aging cannot be reversed, only slowed down a bit.

And just a couple of hundred years ago being 40 was considered old. In the grandparents range. So if you are 16, and work your ass off in the field or with some harmful chemicals at 30 you look like an old bag...

However, inside you are not that old. Applying cosmetics can go long ways if your appearance is a bit worn off while on the inside, you are generally in a good shape.

Having kids takes most of your attention and energy, so you have less time to contemplate on how short the life is and to do something in scientific way and probably see some results in 30 years.

Posted by: Cuberat at October 1st, 2018 1:23 PM

Most women would find comments such as the above that generalize women and their motivations to be insulting. I've seen a number of individuals who identify themselves as female (and seemed to be genuinely female) make a few thoughtful and enthusiastic posts on a particular life extension forum and then disappear; I'm guessing they were made to feel unwelcome in some way. An interest in cosmetic enhancement is not necessarily for maintaining 'sexual market value' (though if true, what of it? women shouldn't want to have sex? is it not a source of pleasure for most people?); both men and women face age discrimination in the workplace and seek cosmetic anti-aging treatments as a result. I see interest in cosmetic anti-aging as a gateway to interest in biotechnological life extension, which only now has become technically plausible. Expect more interest on the part of women in the future; it is up to life extension community to make them feel welcome if they truly want their support.

PRP (platelet-rich plasma) based treatments have increased in popularity due to their cosmetic applications which seems to have resulted in more scientific studies on PRP. The mechanism of action is not yet well understood; I would not be surprised if part of the efficacy can be explained by increased engraftment of physiologically migrating stem cells (every night, apparently, some of our hematopoeitic stem cells take a walk*). Some of these cosmetic treatments are, from a biological point of view, pretty interesting.


Posted by: CD at October 1st, 2018 2:15 PM

CD, I have no problem with women wanting to maintain or increase their SMV. In fact I encourage it. I seek to maintain MY SMV. Why should women not want to do the same? Your point about age discrimination in the work place is also good as it is a real issue right now.

I don't consider my previous comments about women to be insulting in the least simply because I have the same motivations myself. How can ascribing a particular motivation to someone be insulting if in fact I have the same motivation myself? If its insulting, then I'm insulting myself as well.

I am well aware that one of the current pioneers in DIY medicine is a female.

Posted by: Abelard Lindsey at October 1st, 2018 10:28 PM

I think the focus should be on preventing age related diseases instead of greater longevity.
Lot of women are really scared of becoming ill and they usually keep care of themselves better than men.
As example, senescence clearing therapy should be presented as a way to reduce chance of getting cancer, not as a longevity treatment.

Btw some of the comments above are really sexist.

Posted by: aury78 at October 2nd, 2018 8:52 AM

@Abelard Lindsey
Sorry if I took your comments the wrong way. As far as spending goes, some get good results spending very little, others spend a lot with poor results; as with every other spending decision, caveat emptor.

Personally, I like a lot of nerds, especially Ray Kurzweil. Unfortunately, Michio Kaku gets more media exposure.

Life extension will be the result of eliminating the diseases that kill - it's really a two for one deal. Senolytic therapies and others that generally improve healthspan should get most people to ~ 115 yrs - the 'wall of death'. If it turns out that that the wall of death is due to amyloid accumulation, then treatments for the major neurodegenerative diseases should increase lifespans further - and I'm sure we would all like to to eliminate Alzheimer's and the synucleopathies (Parkinson's, Lewy Body Dementia and Multiple System Atrophy).

Posted by: CD at October 2nd, 2018 10:06 AM

Michio Kaku is more charismatic. And had more time to build credibility and his public image. After all, he started with popularizing science. Then switched to futurism. Kurzweil has less charisma than Michio Kaku but more than Aubrey but he is even more remote from the general public than LEV. He has done a nice job with popularizing his ideas. However, he stubbornly insists that almost all his predictions are essentially correct instead of regrouping and redefining them. He was expecting to have get meaningful rejuvenation therapies by now or within a few years.

But we don't have to reach the singularity to have LEV. There is no law of physics that precludes us from being immortal. It is just that our body machinery is brittle and complicated to understand and fix.But there is nothing impossible. It is just a very hard problem. And once we reach LEV, then we can slowly wait for all other amazing discoveries. Until then it is race against the clock, with every minute people dying and suffering...

Posted by: cuberat at October 2nd, 2018 6:08 PM

"Prediction is very difficult, especially if it is about the future." - Niels Bohr

I met my first Kurzweil fan and transhumanist around 20 yrs ago at a dinner party when I was interviewing for a PhD program in immunology. She was a grad student in her 40's, a former nurse and a single mother of four children. Her background and circumstances very impressive and inspiring to me; I had been worried about my age and health issues being seen as impediments. I tried my best to hide the latter but stress has always been a big trigger for me and I managed to sprout a bunch of petechiae on my inner forearms during a one-on-one interview with a rheumatologist - so much for that. The transhumanist grad student told me about her beliefs and I reacted with skepticism despite a long interest in science fiction and having made LEV type arguments myself in college (and being ridiculed for them). Due to the stress I was in full Aspie mode and said at one point, "It's the the year 2001, where's my flying car?"

Around 10 years ago I predicted that in 5 - 10 years we should have switched over to mostly automated driving technology {sigh}. You'd think ~40,000 road accident deaths per year in the US alone would be sufficient motivation to move a little quicker on that front. There's also the waste of gas/energy (automated systems will be much more efficient than human drivers), unnecessary parking lot and road construction, and the huge number of wasted hours in traffic. Expect delays.

Posted by: CD at October 3rd, 2018 9:07 AM
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