Scientists have made a discovery that could lead to better treatments for diabetes in the future, with a protein injection administered directly into the brains of rodents with type 2 diabetes putting the animals into remission for several months.
Both mice and rats were injected with a low dose of synthesised Fibroblast Growth Factor 1 (FGF1), a growth-promoting protein known to lower blood glucose levels in diabetic mice. But while FGF1 had previously been shown to restore healthy blood sugar levels in mice for up to two days after injection, the same hormones injected directly into the animals' brains provided a dramatically extended effect: up to 17 weeks of what the researchers call a "sustained remission".
While it might not be quite a cure, it's still a big improvement on previous research with FGF1, and the findings could lead to a new potential target for diabetic treatments – focusing on the brain's role in regulating blood glucose levels, rather than other organs and organ systems in the body.
"We thought that FGF1 could be acting in the brain, because the receptors for FGF1 are highly prevalent there," gastroenterologist Jarrad Scarlett from the University of Washington told Laurie Tarkan at EndocrineWeb. "We think that diabetes represents a dysfunction of neural circuits within the brain. What FGF1 is doing is acting upon these circuits to ameliorate the dysfunction."
And the level of that effect surprised even the researchers, who thought they might see similar results to what had previously been shown when diabetic mice bodies were injected with the protein.
"We were expecting the results to last 48 to 72 hours, not several months," Scarlett told EndocrineWeb. "We think it's stimulating synaptic remodelling within these circuits."
When the first diabetic mice had the peptide injected just once into their brains, the researchers observed increased production of the brain's neuroprotective proteins, and strengthened connections in the hypothalamus, which helps to regulate appetite and metabolism. The animals' systems improved their clearance of glucose after meals, leading to normalised blood sugar levels.
To confirm the results, the team repeated the experiment on two more sets of animals, administering the single injection of FGF1 to rats, and to a second group of mice, which had been bred to develop type 2 diabetes in a different manner. Once again, the one-off approach produced long-lasting remission from diabetic symptoms.
While the study's impressive results are clearly limited to animals – and it's unlikely we'll see brain injections offered as a treatment for type 2 diabetic humans any time soon – the findings, reported in Nature Medicine, could indicate a new path for future diabetes research.
"We are entering an era where, really, when it comes to treating diabetes using insulin or insulin-related treatments – which they all are – we've gotten as far as we're going to get," lead researcher and endocrinologist Michael W. Schwartz told Melissa Healy at the Los Angeles Times. "[T]here probably are not going to be breakthroughs by hammering away at the same drug targets… So if there's going to be a paradigm shift in finding treatments that might complement or make other drugs more effective, then targeting the brain might be the way to do this."
Although any human treatments stemming from this research would be several years away, the researchers suggest people wouldn't need to suffer a needle to the head to see the benefits of any future brain-targeted remedies. They say it's more likely that some form of nasal ingestion could confer the same effects.
For the hundreds of millions of type 2 diabetics around the world forced to deal with daily injections to manage their blood sugar levels, this kind of innovation can't come soon enough.