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[reason]

Researchers here demonstrate extended life spans in rats as a result of life-long regular transplantation of stem cells. The specific mechanisms are unknown, but the researchers suggest that the proximate causes involve altered levels of various signal molecules leading to better operation and maintenance of native cells and tissues. Given that one study can't measure everything of interest, this should probably be taken as a preliminary set of suppositions, though reasonable given what is known of stem cell therapies at this point. Following on from this work it is definitely the case that more life span studies should take place for stem cell treatments.

Aging brings about the progressive decline in cognitive function and physical activity, along with losses of stem cell population and function. Although transplantation of muscle-derived stem/progenitor cells extended the health span and life span of progeria mice, such effects in normal animals were not confirmed.

Human amniotic membrane-derived mesenchymal stem cells (AMMSCs) or adipose tissue-derived mesenchymal stem cells (ADMSCs) were intravenously transplanted to 10-month-old male F344 rats once a month throughout their lives. Transplantation of AMMSCs and ADMSCs improved cognitive and physical functions of naturally aging rats, extending life span by 23.4% and 31.3%, respectively. The stem cell therapy increased the concentration of acetylcholine and recovered neurotrophic factors in the brain and muscles, leading to restoration of microtubule-associated protein 2, cholinergic and dopaminergic nervous systems, microvessels, muscle mass, and antioxidative capacity.

The results indicate that repeated transplantation of AMMSCs and ADMSCs elongate both health span and life span, which could be a starting point for antiaging or rejuvenation effects of allogeneic or autologous stem cells with minimum immune rejection.

Link: http://dx.doi.org/10.../sctm.2015-0011

View the full article at FightAging

[niner]

This is a very cool result, but can someone explain why human stem cells are not rejected by F344 rats?  Are they immunocompromised in some way?

[nowayout]

This is a very cool result, but can someone explain why human stem cells are not rejected by F344 rats?  Are they immunocompromised in some way?

 

No.  It is not fully understood why mesenchymal stem cells are not rejected (at least at first), but it is known that they produce a number of immunosuppressive factors that inhibit host immune responses.  They also express very low levels of major histocompatibility complex (MHC) molecules on their surface, which helps hide them from the host immune system.

 

If they differentiate, then they will of course then be rejected. However, there isn't consensus on whether they actually differentiate.   Their apparently beneficial effect in this case may just be from the factors they produce as stem cells. 

 

Also, there are come claims that MSCs are eventually rejected, or are rejected in some recipients, so it is not a hard and fast rule that they aren't. 
 

Edited by nowayout, 01 September 2015 - 02:25 PM.

[Kalliste]

Great news given that stem cells are well known to the public. This should be used to "prove" that rejuvenation is possible.

[niner]

Great news given that stem cells are well known to the public. This should be used to "prove" that rejuvenation is possible.

 

This raises a question:  What is "rejuvenation", and what is "slowing of aging".   To hear some people tell it, the former is the only thing that matters, while the latter is a waste of time.   The rats who got regular injections of human stem cells lived longer, but they didn't show that an old rat could be made to be more youthful.   I think it's likely that this technique is in fact rejuvenative, for what it's worth.  I think it's also likely that all rejuvenative techniques will look like a slowing of aging until they are combined in such a way that all causes of aging are effectively dealt with.

 

There is a lot of stem cell medicine being practiced in various low-regulation countries, some of it of dubious value.  Is anyone offering this sort of protocol for humans?  It could presumably be done with an expanded population of your own cells (autologous transplant), or with immunologically suitable donor cells (allogenic transplant).    What might it cost for such a treatment?

[corb]

The interesting part of this paper is that adipose derived stem cells seem to be more effective than amniotic stem cells - this means the ready and abundant source of exogenous stem cells we can use for regenerative medicine is in fact the better source.

 

Apart from that it reiterates that stem cells can be used as a delivery vehicle for gene therapy besides cell replacement.

Edited by corb, 02 September 2015 - 05:53 AM.

[nowayout]

I don't have access to the full paper.  Was maximum lifespan also extended or just average lifespan?