Closing the Loop

One of the terms most-oft overheard at the recent ADA Conference was the “closed-loop system” for diabetes: when will we have it? is it really viable?Biomechanical_pancreas_2

For those unfamiliar with the term (as I was, novice that I am!), “closed-loop” means a device that combines continuous blood glucose sensing and insulin delivery. Mimicking the function of the human pancreas, the “closed loop” system would monitor glucose levels and, in response, deliver an appropriate amount of insulin. Essentially, this system would perform as an artificial pancreas.

Researchers — at least those I spoke with — now openly admit that they were overly ambitious in predicting the arrival of a functioning and marketable closed-loop system, fabled to be ready in a few years (that was five years ago!) But hopes still run high. The JDRF has it on their short list of aggressive goals. And Medtronic MiniMed’s Long Term Sensor System (LTSS), which links an implantable long-term glucose sensor with an implantable insulin pump, is looking promising in clinical tests. They hope to bring an artificial pancreas to market by 2008.

The technology is tricky, indeed, but the biggest stumbling block seems to be the concept itself.

A system that monitors BG levels, and then provides doses automatically based on that data would be the first to put people’s lives in the hands of fully automated technology. The system would go ahead and administer insulin based on its own readings and calculations. In a truly closed-loop system, this means you wouldn’t even have to enter basal rates, as the unit would react to high BG readings to account for the carbs you ate. If any portion of the system breaks down, the consequences could be grave — because there is no “human intervention” to use common sense, in the case that a BG reading seems off, for example.

“The FDA’s going to have a really difficult time approving a system like that,” a researcher from Abbott noted.


10 Responses

  1. Dr. Roosevelt
    Dr. Roosevelt June 21, 2005 at 8:19 am | | Reply

    I’ve been told that a closed-loop system would be available in the “near future” for over 20 years. So don’t get your hopes up too high that it will be ready by 2008.

  2. Alexis
    Alexis June 22, 2005 at 6:35 am | | Reply

    How would such a system would be able to deal with intense exercise? If your bs were to suddenly drop would you still have to worry about carrying around glucose? I suppose that really wouldn’t be all that bad, instead of diabetics we would simply be hypoglycemics.

  3. Robert
    Robert June 22, 2005 at 11:05 am | | Reply

    I would think that any system that gets approved would need to have double or triple redundancy on the BG side of things which may make it less appealing. I also am not sure on how it would handle lows – would it require the person to also carry an internal supply of glucagon?

  4. DensityDuck
    DensityDuck June 22, 2005 at 1:03 pm | | Reply

    Low BG would be handled the way it gets handled in anyone else–you eat something. People with functional pancreas don’t get lows, they get hungry.

    That said, I would certainly expect this closed-loop system to follow a paradigm other than “basal rate = x.xx units per hour from now until Doomsday”. It would adjust the basal up or down dependent on the current BG reading and its trend (up, down, level.) In other words, it would work in exactly the same manner as a “natural” pancreas; and nobody worries that a natural pancreas is going to suddenly go berserk and start spewing out insulin.

  5. Kathleen Weaver
    Kathleen Weaver June 24, 2005 at 8:22 pm | | Reply

    The closed loop system isn’t going to happen until there is a viable, reliable continous blood glucose monitor system.

    Therasense has been “close” for the past 4 years, but has not been for sale yet.

    Minimed marketed but didn’t sell their Guardian system, but I haven’t seen anything from internet posts on this session on it. Not from you, not from Medline, or any of the other reports.
    I’m not sure you can find it from their website anymore, I’ve looked but not digged.

    By marketed I mean, announced on websites and at pumpers meetings it was coming.

    I’ve met a few guinea pigs (subjects of clinical trials) on the internet for some of the other systems and they claim that
    they aren’t reliable.

    So don’t count on 5 years. Maybe 5 years on the continuous glucose monitor, maybe not.

  6. Kevin McMahon
    Kevin McMahon July 8, 2005 at 6:50 am | | Reply

    Great diabetes blog! Of all the blogs I’ve read recently this is the first one that I’ve been compelled to share some relevant information.

    An alternative approach to continuous glucose is in the research phase of development and involves putting together several existing technologies in a system which will ask patients to test at the 8 to 12 most pivotal times in the day. It’s a similar problem of developing and testing the accuracy of predictive algorithms that consider the patient’s history and data inputs but one that comes with significantly reduced risk.

    LARRY GOLDSTEIN December 23, 2005 at 3:56 am | | Reply

    My daughter has has had type 1 diabetes since age 9.She is now 22.

    The reason progress for a cure or effective treatment is so slow is simple.There is no money in cures only treatments. No one is looking for a cure because that would damage the bottom line.

  8. jessica
    jessica June 23, 2008 at 6:11 am | | Reply

    they are looking for a cure why do you think they take part in walks to cure it. I have had diabetes 6 years now and taken part in all of them. there is hope never say that there isn’t because they are trying. OK


  9. Jason
    Jason August 23, 2008 at 12:06 am | | Reply

    are you kidding me? There will be no cure, to much money to be made. Please tell me you are smarter than that. I’ve been a diabetic for over 25 years and wear pump. I also wear the sencers and my spelling is poor. They will only create ways to make us spend more and more money.

  10. Stayci
    Stayci March 1, 2009 at 9:16 pm | | Reply

    Just as a note, not sure if anyone will read this post since it is four years old. But, i’m an electrical engineering student doing a research project on this exact thing. I am actually able to do this without logarithms, using what is called fuzzy logic. Not sure if I will ever come up with a marketable product, let alone a finished product, but there is hope!!

Leave a Reply