The Science of X-Files: Young at Heart PART I
Some episodes of our favorite television show are campy, fantastical, and sillypants. Some, however, borrowed from current and predicted developments in science. Young at Heart is a little of both.
In the episode, we are met with basically quotidian phenomena: a prison doctor has gone rogue after deciding that this country’s strict limits on human experiments and gene therapy/drug trials spite the body to save the nose, as it were; he absconds to South America, the mythical land of unfettered access to cheap progeria sufferers. (Eh, whatever.) He studies these little children who age at an extremely accelerated pace to determine the secret of speeding up aging because do the opposite and you can slow it down. SCIENCE. He uses this on himself to keep from aging, and he uses it on Barnett, his most “successful” prisoner-patient (on whom he had free rein with the progeria experiments because he just got the prison to declare him dead even though he wasn’t), who would be a success if he weren’t a big ol’ murderer. So we’ve got Mulder and Scully looking for a should-be-dead murderer on the loose, except they’re looking for an older Barnett, assuming he ages in the same direction we do. This is not only some good misdirection, but a great chance for the FBI to show off their 1990s Photoshop skillz.
Anyway, so that explains why Barnett is running and murdering around undetected — he’s pulled a Benjamin Button on his old enemy Mulder (enemy because Mulder put him in prison way back when). Oh, also, he has a salamander hand.
I’m not totally sure why they decided to go with the salamander hand and the progeria/age reversal thing in one patient/prisoner/character. From what I can find, and keep in mind that I know absolutely nothing about science besides, like, plants eat sunshine and there are atoms in stuff and whatever, regenerative medicine (the salamander hand) and life prolongation/age reversal are two different fields of research without a lot of cross-pollination. Granted innovations in one would inform developments in the other, but the ability that salamanders and some other creatures have to regrow bits of themselves comes from a totally different element of their biology than what causes progeria in humans.
So how did these two unrelated medical phenomena got smashed into one MotW? Much as we would suspect, the progeria aspects of the plot and the salamander hand were added at different times by different people. The initial draft only included the progeria research, but I guess Chris Carter was like gah boring SALAMANDER TIME when he rewrote the script.(1)
This decision to chase two totally separate forms of (at the time) fringe medicine ultimately proved problematic for later critics of the show, though I consider the episode to be top-notch, X-Files truly hitting its stride, on top of its game. What I find to be a clear articulation of the raison d’être of the show inspires other critics to call it at once “far-fetched” at Entertainment Weekly (2) and “not weird enough” at the AV Club.(3) Maybe nothing is weird enough for the AV Club. (While I disrespectfully disagree with Handlen’s dismissal of the entire episode as “sloppy” and “poorly edited,” I do agree with him that the focus should have been on the government’s willingness to bargain with Barnett for the research he was holding hostage, as we find out from Deep Throat at the very end before Mulder kills the guy and any hope of getting the research back along with him.)
So, we’ve established that this is an unpopular episode with two divergent pseudo-/pre-scientific themes vying for space in the same character. How realistic is the science?
Totally realistic that we could grow a new hand, and probably possible in our lifetimes, but it’ll be human, not salamander. Lee Spievak famously grew back his fingertip in 2008(4) using powdered extracellular matrix extracted from the tissue of pig bladders. What they do is take out the bladder, take some tissue, soak that shit in acid to get rid of the cells leaving only the glue that holds em together, and then powder it. For some godforsaken reason, the matrix that holds animal cells together (i.e., extracellular) is intrinsically part of organ development and growth, and so when applied to Lee’s missing finger, it straight up grew a new finger. And not a globular, gross, three-digit salamander hand like in Young at Heart; it was a proper, human finger. The salamander hand looked pretty cool on television, and it is extracellular matrix that allows ‘manders to grow back their limbs, but the limb that grows back is controlled by the organism growing them, not the source of the ECM.
A lot of the research that my lazy and cursory library search turned up looked at ECM in drosophilia (flies), zebrafish, and xenopus (‘manders). For more, read Rodrigues et al. “Skeletal muscle regeneration in Xenopus tadpoles and zebrafish larvae,” Developmental Biology 12:9 (2012). Hans-Georg Simon also wrote a more accessible article about why we caint quite do the same thing (which is BULLSHIT): “Salamanders and fish can regenerate lost structures – why can’t we?” Biology 10:15 (2012). It goes without saying that basically every abstract of an article about salamander/fish regenerating their bodies starts with something wistful about how mammals can’t do it because of their immune system and scarring.
Basically, when mammals have a major wound, macrophages (pac-men) show up about a day or two later to chomp up the bad bits.(5) They replace neutrophils, which are the most common type of white blood cells, when there is a wound and they manage the healing process. They shoot out all this weird goo, such as proteases (which break up proteins and also do stuff with blood clots), growth factors (which I sure hope is transparent in meaning), and cytokines (which do immune system stuff). The cytokines that the macrophages be chillin’ with attract other cells that come help with the wound clean-up. When the macrophages get out of there, that’s when the inflammation ends and the wound starts to contract. They also help out with skin repair, but that was a whole other set of studies I didn’t want to read. Here’s the deal though: in the salamanders, the macrophages still show up. Cool! But instead of helping to get the epithelial tissue back up and running (remember the four types of tissues? connective, muscle, nervous, and epithelial!), they do a bunch of other stuff, but unfortunately I lost interest before I got to that part. The bottom line is that regenerative medicine might grow you a new human hand sometime soon, but not a salamander hand.
Stay tuned for part II, wherein I read some articles about progeria and tell you about them.
(1) Frank Lovece, The X-Files Declassified, 1996
(2) Entertainment Weekly, X Cyclopedia: The Ultimate Episode Guide, Season 1
(3) Zack Handlen, “The X-Files: Young at Heart/E.B.E./Miracle Man,” The AV Club: The TV Club, 2008
(4) Matthew Price, “The man who grew back his finger tip,” BBC News, 30 April 2008
(5) My understanding of macrophages is derived from James Godwin et al., “Macrophages are required for adult salamander limb regeneration,” Proceedings of the National Academy of Sciences 110:23 (2013), 9415-9420
CONFIDENTIAL TO MY IMMUNOLOGICAL FRIENDS: Please correct me where I have misrepresented or misunderstood sciencey things.