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'Artificial Pancreas'

tim2000s said:
I don't know if you've missed the 670G from Medtronic? That is the first commercial system approved by the FDA and it does as described, within conservative bounds. Why conservative bounds? Precisely due to the nature of the above concerns.
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I had missed it until I found your blog page It's a start, but I'd still be pushing for better. It's the geek in me. I see something, and think 'how could I improve that?'.

Out of interest though, how much insulin would someone typically use in say, a week? So potential reservoir capacity, if it were possible to create an implantable device. And on that point, would insulin degrade/stay safe if it were being stored at body temperature?
 
The concept of someone with Type2 using a fully closed loop system and hence not having to think about the carbs they eat fills me with dread….. (Increased insulin resistance is a real risk with Type2, yet closed-loop systems could be great for anyone eating very low carb.)
 

Depends on what they eat. Whilst I’m low carb, it’s around 30-35u a day. If eating 150g a day, then more like 45-50u a day.

Add to that the temperature effect (37C will degrade insulin fairly quickly. 25C is the normal level at which there is concern).

Ultimately there’s little point in creating an implantable insulin delivery system due to needing to change batteries & insulin (you’d need the device to be able to communicate and radio frequencies don’t come cheap in power terms) and the life of the insulin. You’re better off with the idea of an implantable biological system that feeds itself and produces its own insulin.
 

I think it would also require a fair amount of research. Typically the dosing algorithm in T2 is rather different than for T1.
 

Thanks. Temperature would be a challenge then!


I think that would be long term, and then it may become possible to use stem or gene therapy to grow/regrow beta cells.. Or clone your own pancreas with corrections. Shorter term, it's back to the original artical and paediatrics challenges. So it would be nice to have a compact & discrete solution that lets kids be kids. But then kids are volumetrically challenged, and grow, which adds challenges with implants. But they're not necessarily unsurmountable, so for example these exist now:-

https://en.wikipedia.org/wiki/Port_(medical)

And with some creativity, could also function as charging ports. Or there's induction, but that's got it's own risks and challenges. RF isn't neccessarily a showstopper. You could use ISO13157 NFC, so the implant side could be near-passive and powered via a phone or stick-on repeater. Range would be limited direct to phone, and vendors can complicate that, eg Apple's proprietary implementation. Or they can make life harder by only permitting inefficient protocols (Bonjour, Apple!). It would also depend on what functionality you want to offload to a mobile app. If it's mostly data presentation, then that makes it simpler, and functions like alarms might be better achieved via implant.. So figure something like a mobile's vibrator inserted near bone, and that would likely wake you faster than a phone near the bed.
 
So now you need multiple ports (for insulin and power) and the associated exposure at skin level. That creates some rather interesting infection possibilities. There is also the insulin problem. The majority of manmade insulin contains Cresol which crystallises in the delivery mechanism. There is a non-cresol one but even that has shown problems within the Diaport.

For the most part, implanted pump based devices needing reloading just aren’t really practical on a number of levels with the current state of technology. Who knows where it may get to with things like Nanotechnology but there’s certainly a long way to go.
 
tim2000s said:
There is a non-cresol one but even that has shown problems within the Diaport.
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Yup. Often there are 'chicken & egg' challenges in product development. So an implantable reservoir requires a more stable insulin, but there's no current need/market for that. And developing both increases cost & regulatory burdens.


Yup, or different forms of pumping, ie diffusion/perfusion. Those could reduce size and power.. Not that power is necessarily a problem. Back to pacemakers, early ones used RTGs as 'batteries'.. But there'd be.. issues with going back to Pu-238 instead of lithium. I think some made in the '50s or '60s still work. Better sensing seems more achievable though.
 
The biggest issue with pumping is accuracy in dosing. There have been multiple pumps using non-plunger methods and many have fallen by the wayside with issues on reliability and dosing accuracy. That has to be consistently right for something that’s implanted.

Again, not insurmountable, but development cost needs to be recovered and that may be a challenge.
 
Indeed, but it seems that both the implanted pump and the diaport have similar issues, in that the peritoneal cavity tube gets blocked. The main benefit of the implanted pump is that the insulin drips onto the liver, as is also done with the Diaport. Both have benefits and issues. What you really want is something like a Diaport that a pump locks onto, making it easily refillable/changeable whilst having the same peritoneal access.
 
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