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I'm a type 1 diabetic. None of the examples mentioned truly replace the endocrine functions of the pancreas lost in the disease progression. They do, however,

by gabroo 5y ago

I'm a type 1 diabetic. None of the examples mentioned truly replace the endocrine functions of the pancreas lost in the disease progression. They do, however, use a sensor that measures blood glucose (fairly accurately) and a controller that estimates how much insulin to give (very crudely). Maybe this seems unintuitive, but the bottleneck of these systems is not the hardware or the control algorithm, but rather the time it takes for the insulin to start "working" once injected. In a normal situation, the pancreas secretes insulin directly into the hepatic portal vein and reaches peak concentration within minutes. When you inject insulin, depending on how good ($$$) it is, it can take anywhere from 2-4 hours to peak [1]. In technical terms, you have a closed loop controller with a very slow actuator, which severely limits how tight the control can be. There is ongoing work to make faster insulins. But personally, I think the "cure" for type 1 diabetes will come from restoring the insulin-producing capabilities of pancreatic islets, or synthetically adding such capabilities to other highly vascularized tissues. Also worth checking out is Tidepool, an organization trying to take an open source closed loop controller through FDA submission. https://www.tidepool.org/automated-insulin-dosing https://www.tidepool.org/automated-insulin-dosing [1] https://images.squarespace-cdn.com/content/v1/5b7c64af620b85f7900691ed/1536679717267-QERDYTZUVY6IL7PGCKHE/blog3+4.png https://images.squarespace-cdn.com/content/v1/5b7c64af620b85...

andreareina 5y ago
Do we know approximately why synthetic insulin is that slow, e.g. is it the delivery mechanism or is it the formulation?
- micro_cam 5y ago
  Delivery I believe, it takes a while to get absorbed from where you inject it and spread around. You can speed this up by exercising the area it was injected into or even a hot shower to increase blood flow. There is also a new faster acting inhaled insulin, afrezza, but that won't work with the pumps discussed here.
sgt101 5y ago
My daughter has the cambridge (CamAPS) one : https://camdiab.com/ https://camdiab.com/ My understanding is that it has a predictive algorithm based on what it's learned about the response of the user. Also we work out carbs and put them into the device 20 minutes before meals so that it can pre-dose. Another advantage is the minute to minute monitoring providing data that allows us to understand how well she is doing and what we need to do to improve her levels.
- dreamcompiler 5y ago
  How much pre-dosing happens? My concern is what happens if your daughter for some reason is unable to eat her meal, and does she have glucose available for this case? (I don't know how old your daughter is; if she's a child always under your supervision this is less of an issue. I'm more interested in how people manage the process when they're independent, and how the machine tells you it's pre-dosing so you're aware you need to eat something.)
  - sgt101 5y ago
    Delivery of the "bolus insulin" happens when the meal is calculated 20 minutes before it's eaten. This is done manually, you have to figure the number (grams of carb) put the number in to a special screen (press a button to access) and confirm (three more steps) and it buzzes and says "delivered" at the end of the process. If you don't eat your meal then the bolus is active and I guess that there are problems, this hasn't happened for us yet. In the background the system delivers basal insulin - this is a low dose of insulin that is used by the app to manage glucose levels. The sensor shows the level, the app makes a prediction and then delivers insulin (or decides not to) in order to keep within limits. Sometimes she can go low or high (below 4 or over 7) when she goes low sometimes she has to eat sweets, when high sometimes engage "boost" mode. There is also an "ease off" feature that she engages to tell the system to expect a low insulin period; for example before playing sport. The drawback of having a sensor is that you get alarms. The benefit is that you know what is happening and can act. The Camaps system with the always on pump means that you get relatively few alarms or overshoots. She is in bounds for a much improved amount of time (I think 95+% vs <70% before), also the over/undershoots are smaller and more quickly managed (I have no stat, but I have seen the data and believe this to be so). My daughter is nearly 12 and is able to manage this independently. It's certainly much easier for her than the injections were. I think that as a parent or school this would be much easier to manage for a smaller child - you would have to not give them the password for the phone of course! I'm no expert but I expect that there would be a lower limit for when the app will work because little kids are so different - but I don't know.

by gabroo 5y ago

andreareina 5y ago

Do we know approximately why synthetic insulin is that slow, e.g. is it the delivery mechanism or is it the formulation?

micro_cam 5y ago
Delivery I believe, it takes a while to get absorbed from where you inject it and spread around. You can speed this up by exercising the area it was injected into or even a hot shower to increase blood flow. There is also a new faster acting inhaled insulin, afrezza, but that won't work with the pumps discussed here.

sgt101 5y ago

My daughter has the cambridge (CamAPS) one : https://camdiab.com/ https://camdiab.com/ My understanding is that it has a predictive algorithm based on what it's learned about the response of the user. Also we work out carbs and put them into the device 20 minutes before meals so that it can pre-dose. Another advantage is the minute to minute monitoring providing data that allows us to understand how well she is doing and what we need to do to improve her levels.

dreamcompiler 5y ago
How much pre-dosing happens? My concern is what happens if your daughter for some reason is unable to eat her meal, and does she have glucose available for this case? (I don't know how old your daughter is; if she's a child always under your supervision this is less of an issue. I'm more interested in how people manage the process when they're independent, and how the machine tells you it's pre-dosing so you're aware you need to eat something.)
- sgt101 5y ago
  Delivery of the "bolus insulin" happens when the meal is calculated 20 minutes before it's eaten. This is done manually, you have to figure the number (grams of carb) put the number in to a special screen (press a button to access) and confirm (three more steps) and it buzzes and says "delivered" at the end of the process. If you don't eat your meal then the bolus is active and I guess that there are problems, this hasn't happened for us yet. In the background the system delivers basal insulin - this is a low dose of insulin that is used by the app to manage glucose levels. The sensor shows the level, the app makes a prediction and then delivers insulin (or decides not to) in order to keep within limits. Sometimes she can go low or high (below 4 or over 7) when she goes low sometimes she has to eat sweets, when high sometimes engage "boost" mode. There is also an "ease off" feature that she engages to tell the system to expect a low insulin period; for example before playing sport. The drawback of having a sensor is that you get alarms. The benefit is that you know what is happening and can act. The Camaps system with the always on pump means that you get relatively few alarms or overshoots. She is in bounds for a much improved amount of time (I think 95+% vs <70% before), also the over/undershoots are smaller and more quickly managed (I have no stat, but I have seen the data and believe this to be so). My daughter is nearly 12 and is able to manage this independently. It's certainly much easier for her than the injections were. I think that as a parent or school this would be much easier to manage for a smaller child - you would have to not give them the password for the phone of course! I'm no expert but I expect that there would be a lower limit for when the app will work because little kids are so different - but I don't know.