IEEE Spectrum June, 2015 - 87

diabeteS haS a new
enemy: robo-pancreaS

co nTi n u e d f ro m pag e 4 3

problems with responses in the form blood sugar by helping the body-
"if this happens, do that; if that happens, particularly the liver-store it. In the
do this," says Aaron Kowalski, a medi- liver, glucose is converted to glycogen,
cal geneticist who heads artificial- a kind of animal starch. Glucagon works
pancreas research for the JDRF.
in the opposite direction by stimulatA third kind of algorithm tries to ing the liver to turn that starch back
model human physiology, for instance into sugar and dump it into the bloodby considering how quickly food passes stream. People with diabetes often
through your system and how long the carry a special pen charged with gluinsulin takes to work. "The beauty of cagon for others to use on them in case
this approach is that it's like chess pro- they faint from low blood sugar.
gramming: You reset the variable when
In a dual-hormone pump, insulin
your opponent makes his move-that is, serves as the accelerator and glucagon
when new data arrive," says Kowalski.
as the brake, in principle allowing for
Tuning these algorithms requires big finer control. But at a diabetes techdata, gathered from both the individ- nology conference held in Paris this
ual patient and the larger community of past February, funding organizations
patients. Hovorka's group at the Univer- appeared to have doubled down on the
sity of Cambridge is conducting trials of simpler one-hormone system in the hope
advanced systems in the home, not just that it will get approved more easily.
in controlled settings. Hovorka is also
One cause of the change was a recent
working with a corporate partner, but he report by researchers from IRCM. They
won't say which one. (He notes, however, compared the one- and two-hormone
that only two companies are pushing the systems and found no significant advanclosed-loop solution now: Medtronic and tage for the dual-hormone method. Their
Animas Corp., in West Chester, Pa.) He report seems to have had an effect.
says his algorithms learn by doing and
"Prior to Paris, I'd have said the jury
so adapt to the patient.
was still out," says IRCM's Remi Rabasa"The algorithm analyzes during the day Lhoret, one of the authors of the report.
and between days for short-term learn- "Now I believe the jury is not out. Other
ing and also longer term," Hovorka says. teams working on the single-hormone
"If somebody goes skiing, you can see approach have progressed immensely.
a drop-off in blood sugar, and the sys- The JDRF told us in a private meeting:
tem has to be able to cope. Every 10 to You are doing a good job, and we want
12 minutes we run the algorithm for pre- to put all our money on bringing the
dictive control. We have a number of closed loop to market."
models running in parallel, with each
What's next? As the millions of people
given a probabilistic value based on how with type 1 diabetes work out the kinks
well it fitted the data in the past.
in the new technology, it will spread to
"We can achieve what no other tech- the hundreds of millions with type 2 dianology can do now," he says. "Hypogly- betes, many of whom would also bencemia [low blood sugar] is down 30 to efit from insulin but shy away from it
50 percent," Hovorka says. Patients because of the needles and the bother.
spent 20 percent longer in the targeted
Now that the artificial pancreas is
zone for blood sugar-not too high and finally within reach, we can look back
not too low.
at this as the perfect case study of exces"It's good enough to use now-I believe sive technological optimism. A machine
so," he insists.
that senses which way your blood sugar is
going and keeps it on the right track-how
hard could it be? How long could it take?
one of The mosT fraughT quesHard as hell. And 50 years. n
tions in the robo-pancreas community has been whether to stick with
insulin alone or to add a pump for the Post youR commEnts at http://spectrum.
hormone glucagon. Insulin lowers ieee.org/sensorsdiabetes0615

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Table of Contents for the Digital Edition of IEEE Spectrum June, 2015