Published in the journal Cell Metabolism, the study builds off of previous research linking diabetes with changes in the brain. Prior studies focused on the branched-chain amino acids (BCAAs) that function as protein building blocks. Excessive levels of these amino acids are found more often in obese and diabetic patients than those of the general population. These studies have demonstrated that an increase in BCAA levels usually happens years before people develop symptoms of diabetes.
Although research exists about these amino acids, scientists had not yet known how the disintegration of these acids becomes compromised in patients with obesity and diabetes. Researchers involved with this study attempted to answer this question after research was published that hinted BCAAs might be linked to insulin signaling in the brain. With their study, the team tested on mice, rats, roundworms, prediabetic monkeys and humans and confirmed that there is a link between higher BCAAs and compromised breakdown of these molecules in the liver.
This pathway was actually discovered to be the same among all the different species that were studied. Such mechanisms that are considered “consistent throughout evolution” are usually extremely important biologically. One of the head researchers of the study, Dr. Christoph Buettner noted that “our study results demonstrate for the first time that insulin signaling in the mammalian brain regulates BCAA levels by increasing BCAA breakdown in the liver. This suggests that elevated plasma BCAAs are a reflection of impaired brain insulin signaling in obese and diabetic individuals.”
One of the main important components of this study is the fact that rats that had compromised insulin signaling in the brain also showed higher plasma BCAA levels and compromised BCAA breakdown in the liver. Because this shows brain insulin signaling might cause the increase in BCAAs in people who are prediabetic, this suggests insulin resistance could be beginning in the brain. There has been a growing body of research on the links between diabetes and the brain. These studies will almost certainly come to a common consensus on the connection between the two, which will hopefully lead to more advanced therapies to both combat and prevent diabetes.