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Israeli scientists develop tissue implants that won't be rejected

israel21c.org

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Re: Israeli scientists develop tissue implants that won't be rejected

#21

Post by reubenswartz »

weberc2 wrote: post #12
vibrio wrote: post #11

Earlier quoted context omitted.

Many ways you could a semester of immunology on this. High a level there are molecules called MHC (Major Histocompatability Complex), or HLA (Human Leukocyte Antigen). They are very important to the immune system in a number of ways. Any individual has a few sets of these, and there are many different genetic types of these molecules so the differences between any two people can be many. The immune system is even sen…

Apologies for an unsubstantial comment, but biology blows my mind. Do we know when these features in our immune system evolved? I assume something this foundational is shared with fish or maybe earlier?

Vertebrates have an adaptive immune system. It’s astounding from a biological and information theory perspective. Genes basically mutate themselves so they can form an enormous variety of proteins instead of the typical one to one mapping of gene to protein. Then there is a protein selection process that weeds out those antigens that bind to the host of that don’t bind to anything, leaving those that can bind to foreign proteins. (There’s another process to replicate antigens when they attack something.)

At least, that’s my primitive understanding. Come on HN, please someone fill in the real story, because I’d love to understand it better. :)

Re: Israeli scientists develop tissue implants that won't be rejected

#22

Post by pjschlic »

azernik wrote: post #20
andy-fillebrown wrote: post #18

This is interesting stuff but I don't think the article describes anything groundbreaking. The cells used by the scientists in the article are called adipose-derived stem cells and their applications are already well known in the regenerative medicine industry. See https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3668445 The biologists I develop software with have been talking about adipose-derived stem cells for over a…

The joys of press releases vs. actual scientific papers.

The innovation is personalized hydrogels built to avoid rejection, not the induced pluripotent stem cells which were re-differentiated into things. The key was the structural materials which hold those cells.

https://onlinelibrary.wiley.com/doi/10.1002/adma.201803895

Re: Israeli scientists develop tissue implants that won't be rejected

#23

Post by andy-fillebrown »

pjschlic wrote: post #22
azernik wrote: post #20

Earlier quoted context omitted.

The joys of press releases vs. actual scientific papers.

The innovation is personalized hydrogels built to avoid rejection, not the induced pluripotent stem cells which were re-differentiated into things. The key was the structural materials which hold those cells. https://onlinelibrary.wiley.com/doi/10.1002/adma.201803895

That makes sense but is hydrogel rejection really a thing? I thought hydrogels were already safe from rejection because they don’t contain anything the immune system sees as a threat. Same goes for collagen, no?

Re: Israeli scientists develop tissue implants that won't be rejected

#24

Post by trhway »

claytonius wrote: post #17
riazrizvi wrote: post #16

Earlier quoted context omitted.

I thought we already had processes for taking pig organs to use as ECMs (by chemically flushing them of cells) and then reseeding then with a patient’s stem cells? If so then this discovery is about not requiring stem cells, instead they have found a new reliable process to repurpose stomach cells, which are obviously easier to harvest.

You're right that we could already re-seed decellularized pig ECMs with human stem cells, but we have also already been able to derive stem cells from the stomach. I think the main claim that they're making is that by deriving both the ECM and the Stem cells from the patient, the resulting tissue engineering scaffold is less immunogenic than other methods. While this is somewhat interesting, they get into trouble by…

>decellularized pig ECMs

why not 3d print the ECMs? Isn't it just basically collagen with some fibrin/laminin thrown into? Do the decellularized ECMs not have any immunogens left? Definitely isn't an issue with the printed ones.

Re: Israeli scientists develop tissue implants that won't be rejected

#26

Post by claytonius »

trhway wrote: post #24
claytonius wrote: post #17

Earlier quoted context omitted.

You're right that we could already re-seed decellularized pig ECMs with human stem cells, but we have also already been able to derive stem cells from the stomach. I think the main claim that they're making is that by deriving both the ECM and the Stem cells from the patient, the resulting tissue engineering scaffold is less immunogenic than other methods. While this is somewhat interesting, they get into trouble by…

>decellularized pig ECMs why not 3d print the ECMs? Isn't it just basically collagen with some fibrin/laminin thrown into? Do the decellularized ECMs not have any immunogens left? Definitely isn't an issue with the printed ones.

Unfortunately even with just collagen we can see an immunogenic response that is annoyingly exacerbated by UV cross-linking of the individual collagen proteins. That's why many of the best manufactured ECMs are cross-linked using a mixture of UV exposure and EDC-NHS. Without photolithography i'm not sure you'd be able to get a resolution high enough to mimic native ECM structures.

Re: Israeli scientists develop tissue implants that won't be rejected

#27

Post by odiroot »

weberc2 wrote: post #12
vibrio wrote: post #11

Earlier quoted context omitted.

Many ways you could a semester of immunology on this. High a level there are molecules called MHC (Major Histocompatability Complex), or HLA (Human Leukocyte Antigen). They are very important to the immune system in a number of ways. Any individual has a few sets of these, and there are many different genetic types of these molecules so the differences between any two people can be many. The immune system is even sen…

Apologies for an unsubstantial comment, but biology blows my mind. Do we know when these features in our immune system evolved? I assume something this foundational is shared with fish or maybe earlier?

Read "The Red Queen" by Matt Ridley. You'd understand that and some more.

Re: Israeli scientists develop tissue implants that won't be rejected

#28

Post by surgeryres »

No one likes to talk about the potential side effects of stem cell therapy. They express tissue factor, which increases after culture required for these treatments. Tissue factor is highly thrombogenic and can cause blood clots.

https://stemcellsjournals.onlinelibrary.wiley.com/doi/full/1...

Re: Israeli scientists develop tissue implants that won't be rejected

#30

Post by scirocco »

azernik wrote: post #20
andy-fillebrown wrote: post #18

This is interesting stuff but I don't think the article describes anything groundbreaking. The cells used by the scientists in the article are called adipose-derived stem cells and their applications are already well known in the regenerative medicine industry. See https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3668445 The biologists I develop software with have been talking about adipose-derived stem cells for over a…

The joys of press releases vs. actual scientific papers.

Gotta love HN as there's always someone with deeper understanding who can give a critics view of "breakthroughs" we find in the news
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