What price are we collectively willing to pay for fewer cavities?
A week or two ago I caught a cool interview with Jessica Sachs on the 24 Oct issue of the SciAm Science Talk podcast, and chose to subscribe to her blog as a result.
She just posted a piece that is a great example of both how totally cool and utterly creepy modern molecular biology can be. The short version is that Jeff Hillman has done some pretty amazing (and potentially scary) engineering on Streptococcus mutans (the micro-organism in your mouth responsible for much of your tooth decay) in an effort to reduce our problems with cavities. He’s done this by:
- Identifying a variety of Strep. mutans that tends to crowd out other varieties.
- Knock out the gene that produces the acid that eats away at your teeth.
- Splice in new genes that produce alcohol instead. It turns out that the acid was crucial to the bug’s waste disposal process, and without it it died. The alcohol can serve a similar function, without being damaging your enamel. And, yes, the amounts of alcohol are so tiny as to have no inebriating effect.
In theory, then, he can introduce this newly engineering bug into your mouth, and it will crowd out the bad Strep. mutans currently beavering away at your beautiful teeth, leaving you with a mouthful of (presumably benign) alcohol producing critters and fewer cavities as a result.
Hillman’s had trouble getting permission to run human trials, though, in part because the FDA is concerned about his bug “escaping” into the wild and having unexpected consequences. They’ve required that he create a way to essentially put the genie back in the bottle if need be, so he’s engineered a version that doesn’t produce a key enzyme it needs, so users will have to swish daily with a solution containing the enzyme to maintain their population of tooth-friendly bugs. His first approval allowed him to work with two people with dentures, but he’s just gotten permission to work with people with real teeth, although “the volunteers will be isolated in a biohazard ward for the study’s one-week duration”.
This all sounds a lot like a Michael Crichton novel, and I’m sure there are those who are dismayed by the FDA’s caution regarding what sounds like a potentially revolutionary win for human dental health. Their concerns definitely aren’t irrational, however, as Hillman’s essentially proposing releasing a deliberately invasive species into the complex ecosystem of human mouths all across the planet. Unfortunately our track record with deliberate introductions ain’t real hot (rabbits in Australia anyone?), and these genies have typically been impossible to re-bottle.
From a commercial perspective, for example, it would clearly be easier to sell the treatment if they removed the need to swish daily, although there’s no doubt good money to be made in selling the swishing stuff, and re-selling the treatment to people that missed their swish and need to start over. Without that safeguard, however, then this can (and presumably will) spread pretty quickly through the human population before we will have any clear idea of the long term implications of replacing a long-standing resident in our mouths.
It’ll be interesting to see how this plays out, and I suspect that the true long-term impact (for good or for ill) won’t be known even in my lifetime. In the meantime, careful who you kiss – you never know what kind of heavily engineered super-critter might be living in their mouth.
Thanks to dhammza for the cool photo.
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