LIVINGLIVING
INSPIRED APPROACH
In February 2014 we ran a feature on the development of the
BiAP, a Bio-Inspired Artificial Pancreas. Here we catch up with
Nick Oliver, Professor of metabolism at Imperial College, who
reports on current progress of the research. By Sue Marshall.
The artificial pump is a
simple setup, in theory.
Information from a CGM
sensor feeds into an
insulin pump. Within the
pump there is an algorithm. The algorithm
uses the CGM data to adjust the rate
of insulin being delivered in a pump
set for automated insulin delivery. The
sophistication of the algorithm is key to
accurate dosing. It seems likely that CGM
sensors are not going to get much more
accurate than they already are, although in
the future there may be more contenders
in the space (which, at present, is not
very crowded). So improvements have
to be found in the insulins used and the
algorithms.
Says Oliver, "Over time, these
algorithms have developed and evolved.
They can now include information on heart
rate, exercise and even stress. Likewise,
beyond just putting in a carbohydrate
value, there are other things in the body
that affect absorption other than glucose.
Beta cells in normal people would also
respond to levels of amino acids, fat
and other factors, yet at the moment
we rely on just a blood glucose reading
and a carb count to calculate a bolus.
An artificial pancreas is not conscious; it
is not able to adjust to factors it doesn't
know about. So we are now working on
algorithms to be adaptive and flexible,
using additional information about activity
and environmental factors. For example, a
child at school may be in the playground
one day and may be inside the next day
due to rain stopping play. An artificial
pancreas system needs to be able to
adapt to that so needs the information."
There is a lot of research going on
regarding a closed loop (or artificial)
pancreas with different approaches
being taken to bringing a viable solution
to people with diabetes. There are bihormonal pumps, which carry both
insulin and a preparation of glucagon in
separate chambers (arguably glucagon
is not, at present, stable enough to be
relied upon). It has been said that it's
important to get just one hormone right
first, and that should be insulin as it is
stable and proven. The subtlety of insulin
delivery is core to a reliable artificial pump.
Genomics are now being used to help
assess the best treatments and delivery
for cancer patients. Can similar insights
be used in diabetes care to improve what
treatments, when?
Bio-inspiration
The BiAP pump has been in development
for about 10 years, since uber-engineer
Chris Toumazou (Europe's 'top inventor')
started looking at how to improve medical
devices. Says Oliver, "He had to start
speaking with doctors, and we found that
our terminology got in the way. When he
was talking about 'variable resistors', as
doctors we would be using the phrase
'membrane channels'. Chris wanted
to replicate a beta cell as an electronic