Fully Functional Bioengineered Tooth Grown In a Mouse

A couple of weeks back the Wall Street Journal reported on the first organ grown in vivo from stem cells — a tooth in the mouth of a mouse. Reader cdrpsab spotted the news on the MedGadget blog; the research had been reported earlier in the PNAS. From the WSJ: "The researchers at the Tokyo University of Science created a set of cells that contained genetic instructions to build a tooth, and then implanted this 'tooth germ' into the mouse's empty tooth socket. The tooth grew out of the socket and through the gums, as a natural tooth would. Once the engineered tooth matured, after 11 weeks, it had a similar shape, hardness and response to pain or stress as a natural tooth, and worked equally well for chewing. The researchers suggested that using similar techniques in humans could restore function to patients with organ failure."

Comments

I have a friend who grew a tooth.

[jcr]

Of course, we all grow teeth at the beginning of our lives, but this friend of mine grew a new tooth when he was in his thirties. He had an extraction, and about two years later, a new one came in. He wasn't one of those people who start out with three ranks of teeth (that's pretty rare too, but not quite as rare a growing a new one as an adult. I think his case got written up in some dental journal.

-jcr

Re:I have a friend who grew a tooth.

[X0563511]

Got a bit of shark in him, eh?

Re:I have a friend who grew a tooth.

[jcr]

Not that I know of, but he wins more than he loses at poker.

-jcr

Re:I have a friend who grew a tooth.

[Mister_Stoopid]

Got a bit of shark in him, eh?

jcr: "No, Why?"
shark: "Does he want some?"

*rimshot*

Re:Start small?

[RuBLed]

The tooth fairy could suck it up with her clearly outdated business model.

Re:Start small?

[Anonymous Coward]

The tooth fairy would then receive a bailout package.

Strange Leap

[Toonol]

The researchers suggested that using similar techniques in humans could restore function to patients with organ failure."

The submitter got me, I have to admit. I was reading the summary, thinking that it would end with "could allow humans to regrow teeth"... but they pulled a zigzag, and went a different direction. Organs. Wow. Did M. Knight Shamalyan write this summary?

Re:Strange Leap

[alannon]

Honestly, I don't think that calling a tooth an organ is very much of a stretch. Teeth have their own blood vessels and nerves, and consist of a large proportion of living tissue. This little blurb provides what I think is a convincing, if hardly exhaustive, argument that teeth are organs.

Re:Strange Leap

[OeLeWaPpErKe]

The problem with growing organs is that in order to get cells to multiply you have to disable certain genes in those cells, or at least reset their counters. Which genes ? Well those that guard against cancer ...

Our bodies go to great lengths to prevent cells from multiplying anywhere and it is only allowed by the human DNA in very specific cases : blood production in the bone marrow, when a woman becomes pregnant, and just before a woman gives birth. There are others, but those are major modifications of human cell's normal reproduction. The body goes to great lengths to prevent cell division in organs once a human being is born, instead choosing to do the bulk of the necessary divisions before birth and then letting those already-existing cells enlarge instead of divide to make a child grow. That's not to say there is no cell division involved in growing a child, but a lot less than you'd think from the size difference.

All 3 of those exceptions are also major causes of cancer : leukemia, endometrial cancer and breast cancer.

Getting stuff to grow is easy, just kill of the p70 gene. Getting stuff to grow safely is hard. Very very hard. Loads of research still need to be done before this can really be risked in a live human being.

Re:Strange Leap

[cnettel]

Solid. References. Now. (For the statement that a majority of growth to maturity just involves enlarging existing cells.) BTW, have you ever heard of osteoblasts and osteoclasts? Those cells are actively renewed and renewing bone throughout life, although they decline with age. You are certainly right that extremely rapid and "deep" division is limited in most organs, as you only need a few divisions and the wonderful gift of exponential growth to get just about any number of cells. The problem of organ regeneration is of course that the respecialization requires a number of "cell generations" in itself. There are some risks involved here, but the current techniques are not simply hardwiring the "on" mode for cell division. In fact, to get any real organ you need the natural "stop" modes and directed apoptosis just as much as you need the ability to start cell division in the first place.

Human Pancreas?

[JakartaDean]

Mr. Scientist, if you happen to get around to doing something like this for a human pancreas, could I order one please? Blood type B+, if it's not too much trouble. DNA available on request.

Yours sincerely,

Dean, on behalf of millions of Type I diabetics

P.S. I *love* hearing about this stuff. The potential for helping millions is incredible.

Re:Human Pancreas?

[Cyberax]

Yes, there are islet cell therapies on the horizon: http://stemcells.nih.gov/info/scireport/chapter7.asp

I have bad teeth

[mcrbids]

They're horrible, and I live in the United States, a culture where teeth are perfect and white or you are nothing. My wife has beautiful teeth, and despite the fact that we have nearly identical brushing and dental care habits, my teeth are horrid, yellow, and falling to pieces, hers are beautiful, white, and basically no cavities.

Sorry - not all teeth are created equal.

So here I am, 30-something, fairly affluent, and having horrid teeth. You think I wouldn't hesitate to spend a few Gs replacing my craptastic old teeth with new teeth with zero chance of rejection? Sure, they will go yellow quickly, just like the last ones did, but that means I'm in my 80s or later before my teeth are in any way unusual. And effectively, that means good teeth for life.

I've been waiting for this kind of treatment. Where do I sign up?

Repeated injuries can cause cancer

[MichaelCrawford]

My ex was a biologist, and told me that the way the healing of wounds is implemented is that cells multiply when there aren't other cells next to them. If there is a hole, then the cells will divide to fill in the gap, with the signal to stop occuring when the dividing cells finally close up the hole. The problem is that that signal to stop gets screwed up somehow sometimes - either it's not produced, or its ignored. There is only a small probability of this happening, but if you are repeatedly wounded, then the probability increases. Some people have a habit of biting the insides of their cheeks. I understand that doing so can cause cancers where you bite.

Screw growing new organs ...

[MartinSchou]

Well, not entirely, but seriously - they've come up with a way to grow new teeth for mammals.

Personally, I would love it if I could go to the dentist and have him replace some of my bad teeth with new ones. One or two at a time would be fine.

Instead of getting fake teeth or fillings when you've abused your teeth to the point where the enamel on the outside of the tooth has worn away, exposing the dentine ... if I could get those replaced? I'd almost be willing to kill for that.

Sure, it'd take time to regrow a new tooth, but I could live with that.

So yeah, screw growing new organs - get me some new teeth!