regenerative medicine


If A Tweaked Flatworm Can Suddenly Regrow Its Head, Why Can’t You?

A "Dugesia liguriensis" flatworm (Wikimedia Commons)

A “Dugesia liguriensis” flatworm (Wikimedia Commons)

Here’s an amazing factoid: Human children up to age two or three can regenerate an entire finger-tip — nerves, bone, blood vessels and all.

Then as the years pass, we lose that ability. But early on, we’ve got a bit of the amazing growability that Narnia showed in its Chronicles. (Remember how, when the world was new in The Magician’s Nephew, an iron bar dropped upon the ground sprouted into a lamp-post, and candies into fruit trees?)

I learned that fascinating finger-tip fact from University of San Francisco assistant biology professor James Sikes (except the associations with Narnia were all mine) in connection with an even more fascinating set of papers just out in the journal Nature.

It was a very surprising finding that one gene can rescue a regeneration process that was lost millions of years ago.

Allow me to sum up: Some of the worms known as flatworms or planarians are superstars at regeneration — “We can cut one worm into 250 pieces and have 250 worms a week later,” Sikes said.

In particular, some flatworms can even regenerate their heads. Other planarians are not so good at the grow-back game. In the new research just out in Nature, scientists find that by tweaking just one gene’s signaling pathway, they can restore the power of regeneration to those otherwise headless losers.

Is this surprising? You bet.

“I was shocked,” Sikes said. “It was a very surprising finding that one gene can rescue a regeneration process that was lost millions of years ago.”

I love this stuff. Here, lightly edited, is my chat with Prof. Sikes:

So tell me, please, why can I not regenerate my head?

[Tolerant laughter.] You want to try?

I might want to try if you’d let me know how to do it…!

It comes down to the issue that the regeneration ability is more limited, the more complex an animal is. Continue reading

Human Brilliance Builds Trachea, Human Idiocy Won’t Let It On A Plane

Ayodhya Ouditt/NPR

If you missed this great yarn from NPR’s national treasure Robert Krulwich, you missed a real treat. Here’s the salt of it: Brilliant scientists custom-engineer a human trachea…but their efforts to use it to help a desperate patient in Spain are almost foiled by Neanderthal airport security types who say the bottle containing the trachea is over the 100 milliliter limit and can’t be brought on a plane. (Oops, now that it looks like Neanderthals may have created ancient cave paintings, I may be insulting them by comparing them with certain airport guards.) All ends well — the scientists hire a small private jet — if expensively.

Here’s a choice chunk, including our local angle:

Now comes the We’ve Never Done This Before part: The trachea was then “dipped” into a bath of Claudia’s cells, to see if they would attach.

A company in America, Harvard Bioscience Inc., of Holliston, Mass., makes a shoebox-sized “bioreactor” for just this purpose. It looks like a rotisserie for barbecuing chickens. Continue reading