Your objection is that they're not also growing the matrix from scratch? Personally, I don't find that to be an interesting distinction. All I care about is that we're getting closer to viable custom replacement organs. I expect the same is true of the people who did the work and those who wrote the headline.

And to add to this, if you can take a cadaver heart, strip it to the scaffolding, and then using a plurpotent stem cell line from your own cells to convert that structure into a functional heart, which can then be transplanted into you without risk of rejection, well that would be pretty much a game changer for all those people dying from congestive heart failure.

Tissue engineering has come a long way. The possibility of building a replacement organ this way is pretty interesting to contemplate in terms of changing peoples lives.

On a Nova Science Now episode they were also talking about using animal organs for their scaffolding.

There is lots of developments like this that looked pretty amazing, 5 years go when i first saw it, why isn't there an easy way to keep track of things like this?

You can use Google alerts and follow the topic.

It is a very important distinction. It is the difference between three sizable but incremental advances - rehabilitating unsuitable donor organs, the potential to use pig organs, and elimination of immune rejection - and the far, far greater advance of being able to grow entire patient-matched organs from scratch as needed with no donor.

Being shackled to the need for a donor organ for tissue much thicker than a centimeter is a big drag on the progression of this field. It is a function of blood vessels, largely - being able to create scaffolds of sufficient complexity and size with the right chemical guides to allow formation of blood vessel networks is still not there yet. Hence the need for the natural scaffold of the donor organ.

I don't think I understand. If they could rehabilitate unsuitable donor organs and didn't have to worry about rejection, there wouldn't be a shortage. Isn't that the end game?

There would still be a great shortage. The supply of donor organs is tiny.

No shortage is more like it. Intact cadaverous hearts are plentiful by comparison to awaiting heart transplant patients. Most heart failures are immediate and fatal, but people who have progressive failure are relatively rare. Transplant patients would conceivably be donors for the program (since most heart damage is soft tissue failure).

You could use a much broader range of donor organs, and not having to worry about matching would vastly increase the number of usable donations.

This is a key distinction. When you make a scientific claim, it has to be accurate, and in this case, they clearly did not grow a heart from scratch.

"SCIENTISTS GROW FULL-SIZED, BEATING HUMAN HEARTS FROM STEM CELLS" makes it sound like they just dumped stem cells in a petri dish and got a fully-functioning, properly shaped heart. Beyond being useful for creating custom replacement organs, that would imply we had godlike powers, because you can't grow a fully functional organ in isolation like that (building that matrix is entirely non trivial, as it happens in concert with all the organs growing around it).

> I don't find [not growing versus growing the matrix from scratch] to be an interesting distinction

I do. Refurbishing means being stuck to nature's blueprint. Growing cells on an artificial matrix means having the ability to engineer useful changes.

There also the minor point of not everyone's hearts being the same size.

Currently decellularized matrix (being stuck to nature's blueprint as you say) is the best substrate for regenerating heart tissue. Artificial matrices we can create (including 3D printing) have nowhere near the complexity of what exists in nature.

That is incorrect. They are not repairing hearts unfit for transplant. They are using human hearts (that are unfit for transplant) as a source of decellularized matrix. That decellularized matrix is then used to re-grow heart tissue using iPS-derived cardiomyocytes (heart cells).

What's an accurate, neutral headline?

Edit: we changed the title to a representative sentence from the article.

Stem cells used to repair hearts unfit for transplant, perhaps?

Same thing but add that it was on a scaffold organ?

I believe the scaffold is a pretty well known 'substrate' requirement for stem cells and is somehow secondary, the previous attempts were much more prototypal nut sized heart.

That was clear from the reading of the article.