The cure for type 2 diabetes may be all in your head, a new study in rats and mice suggests.
With a single shot to the brain, researchers can rid rodents of all symptoms of the disease for months. The injection, a relatively low dose of a tissue growth factor protein called fibroblast growth factor 1 (FGF1), appears to reset powerful neural networks that can control the amount of sugar in the blood.
Until now, it’s not entirely clear exactly how FGF1 does that, researchers report Naturopathy. Early experiments showed that FGF1 did not seem to lower blood sugar in some of the most obvious ways, such as curbing the rodents’ appetite and encouraging sustained weight loss. Nevertheless, because FGF1 is naturally present in human brains, as well as those of rodents, researchers hope the lucky shot may translate into a useful treatment.
The FGF1 finding “at least reveals the brain’s inherent ability to induce sustained remission of diabetes,” the authors conclude. But because scientists already have the protocols and know-how to safely deliver FGF1 to human noggins via intranasal routes, going to clinical trials seems like a no-brainer, they argue.
The authors, led by researchers at the University of Washington, gave FGF1 a crack in animal brain experiments after other studies had seen encouraging results with cousins of FGF1. Those related growth factors can activate some of the same brain signals as FGF1 and lower blood sugar after brain injections in animals. Still, FGF1 could be a more powerful player in the brain, the authors reasoned, because it can trigger an even wider range of brain cell signals. And previous experiments have shown that large systemic doses of FGF1 can lower blood sugar levels in mice.
Researchers injected just one-tenth of that intravenous dose directly into the brains of mice genetically engineered to have a moderate case of type 2 diabetes — which is characterized by abnormally high levels of glucose sugar in the blood that damage the body’s cells and overall health. damage health after a while. After a week, the mice’s blood sugar levels had completely normalized. And they stayed that way for more than four months as long as the researchers followed them. Such dramatic results have only been seen in diabetic patients who have undergone certain bariatric surgeries. When the researchers tested the FGF1 brain shot in rats, they found the same results.
Amid the success of the treatment, the researchers were puzzled by what was going on. Immediately after the injection, the rats and mice reduced their food intake slightly and lost a small amount of weight. But that effect disappeared after the first week. The rodents then returned to the food and weighed the same amount as control diabetic rodents. This means that the drop in glucose was not due to the rodents eating less or having a healthier weight and metabolism – the drop in sugar was due to something else.
Next, the researchers looked for changes in insulin, the hormone that prompts cells to take in glucose and use it for energy. Disturbed insulin production in the pancreas is the cause of type 1 diabetes, and type 2 is stimulated by an imbalance of insulin versus blood sugar (usually caused by poor diet, lack of exercise, and genetics). Injections of insulin, which can treat both types of diabetes, remove excess amounts of blood glucose. But an insulin boost didn’t clear the rodents’ sugar. Insulin levels and the effectiveness of the sugar clearing ways were not changed by the FGF1 injection in the rodents, the researchers found.
Upon further digging, the researchers discovered that the liver and skeletal muscles were behind the reduction in blood sweetness. The liver had started both the glucose breakdown machinery and a system that packages the sugar for long-term storage. Skeletal muscles also absorbed more glucose. But no other tissues or organs seemed to be involved in soaking up the sweet molecule. To the authors’ knowledge, it is the first time scientists have found such a sugar removal method.
It is still unclear exactly how FGF1 drives those changes. Interestingly, the authors noted that rodents with severe type 2 diabetes, which have disrupted insulin signaling, were not cured by the FGF1 injection. The authors speculate that functioning insulin signals may be a critical link between brain activity of FGF1 and the novel desweetening system in the liver and muscles.
The researchers will have to do more work to connect all the dots. And with data from only an initial set of rodent experiments, the findings need to be validated and further tested in more animal and clinical studies. But for now, the researchers are optimistic that the brain, rather than the blood or stomach, may be the sweet spot for finding diabetes treatment.
Naturopathy2016. DOI: 10.1038/nm.4101 (About DOIs).