Novel and Emerging Therapies
Implantable Continuous Glucose Monitoring Devices
Many type 1 diabetics who use insulin have made the transition from self-injections and adjustable glucose infusion pumps to continuous glucose monitoring systems, also known as “closed-loops,” in which an implantable device measures blood glucose and constantly adjusts the insulin infusion rate. These systems allow for continual monitoring and adjustment of the insulin infusion rate without the need for patient predictions (Hovorka 2011).
In one study, type 1 diabetics on implantable insulin pumps were randomly assigned in crossover fashion to their standard therapy or a closed-loop system. The closed-loop system achieved better overnight control of insulin and reduced the risk of hypoglycemia (Hovorka 2011).
The use of integrated closed-loop control has been shown to reduce hypoglycemic episodes 2.7-fold over traditional insulin therapy. Moreover, it provided a 6-fold reduction in overnight hypoglycemia. This represents an important step toward improving patient safety and decreasing the risk of complications (Breton 2012). In another study, a closed-loop delivery system combining glucose monitoring with insulin and glucagon infusions dramatically reduced the number of participants who developed at least one hypoglycemic episode from 53% to 7% (Haidar 2013).
Improving Hypoglycemia Awareness
A major problem in the treatment of type 1 diabetes is patient unawareness of hypoglycemia. This occurs due to defects in the neural response that normally accompanies low blood glucose levels. The result is that individuals with type 1 diabetes may not be aware their glucose levels are falling too low (Cryer 2008). This phenomenon is called hypoglycemia-associated autonomic failure (Vele 2011).
Some evidence suggests that naltrexone (Revia®), a drug used in the management of addictive disorders, may help improve hypoglycemia awareness (Feeney 2001; Blasio 2013). It works by blocking opioid receptor signaling. Studies show that blocking opioid receptor signaling helps improve the perceptibility of hypoglycemia (Vele 2011). As of the time of this writing, naltrexone, at a 25-50 mg/day dose, is being tested in type 1 diabetics to determine whether it can prevent hypoglycemia unawareness (Kumar 2012).
Fluoxetine (Prozac®), the selective serotonin reuptake inhibitor used as an antidepressant, may also be useful for increasing hypoglycemia awareness. In one study, 20 healthy patients were subjected to an experimentally controlled bout of hypoglycemia, treated with 40-80 mg/day fluoxetine for 6 weeks, and then re-tested. The study found that this treatment increased several categories of counter-regulatory responses to hypoglycemia and resulted in an increase in endogenous glucose production (Briscoe 2008). The increased counter-regulatory response may allow patients to be more aware of an impending hypoglycemic episode.
For those who want to avoid prescription drugs, there are nutrients described later in this chapter that suppress alpha-glucosidase and other functions in the digestive tract that can cause too much glucose to be rapidly absorbed.