This is the first installment of a 3-part series covering some of the contributions animals have made to treatments for diabetes. Part 2 will be released next week.
Diabetes was one of the first diseases ever described – around 1500 BCE, both Indian and Egyptian physicians described a condition affecting patients’ urine. In 250 BCE the Greek physician Apollonius of Memphis gave it the name “diabetes,” meaning “to pass through” – because of the increased urination associated with the disease. Various treatments were prescribed throughout the ages. Most were ineffective, with the notable exception of Avicenna of Persia’s mixture of lupine, trigonella (fenugreek), and zedoary seed – this treatment had a marked effect upon the excretion of sugars in the urine. A truly effective treatment only emerged after Frederick Banting and Charles Best developed the first use of insulin in 1921. Since then, our understanding of diabetes has grown substantially, as have treatments for the disease. We now know diabetes to have two main variants – type 1 and type 2, with other lesser types emerging as scientific knowledge advances.
Best (left) and Banting (right) (courtesy University of Toronto)
In type 1 diabetes, AKA diabetes mellitus type 1 or juvenile diabetes, the body destroys the insulin-producing islet cells in the pancreas, leading to elevated levels of blood and urine glucose. People with type 1 diabetes require the administration of insulin to substitute for the insulin that would have been produced by the beta cells and must be vigilant in maintaining blood sugar levels as both high and low blood sugar can cause severe complications. Type 1 diabetes accounts for up to 10% of all diabetes cases or roughly 80,000 children each year. Celebrities with the disease include movie star Halle Berry, Supreme Court justice Sonia Sotomayor, singers Nick Jonas and Brett Michaels and author Anne Rice.
The first diabetes type 1 treatment involved insulin that was derived from cows and pigs and had to be injected every 8 hours. Beginning in 1982, human insulin replaced the animal-derived variety, with the insulin being grown in a laboratory by Escherichia coli (E. coli) bacteria. A more recent development is analog insulin or ‘recombinant’ insulin, which recombines the DNA to deliver insulin that is either more rapidly or more uniformly used by the body.
Starting in 2008, scientists began to develop a ‘humanized’ mouse model of type 1 diabetes. In order to bridge the gap between mouse and human physiology, scientists had previously spent years at work breeding mice that were genetically optimized and able to accept aspects of the human immune system. Researchers have grafted tissue from a working human immune system into these special mice. This mouse model has proven incredibly valuable by providing a better way to research type 1 diabetes, which has led to many new treatments. The breakthroughs are too numerous to list here – the American Diabetes Association has
Now, researchers are once again working with animals to create therapies that will improve the lives of diabetics. In early 2016, two papers described how scientists were able to transplant pancreatic cells similar to the lost beta cells into mice, a process that cured them for six months. Researchers from MIT and Boston’s Children’s Hospital conducted studies with mice and primates to develop a special encapsulation that allowed them to transplant human ‘islet’ cells into the mice. ‘Islet’ cells are regions of the pancreas that contain beta cells. The researchers plan to further test their therapy in nonhuman primates, with the goal of eventual clinical trials in human patients.
Type 1 diabetes has been with us since the start of recorded history. Only in recent years have there been significant gains in our understanding and treatment of the disease – largely thanks to animal research. In 2016, we are closer to having a cure for diabetes than ever before. Millions of people living with type 1 diabetes have already benefitted from animal research-derived treatments for the condition and the near future will see even greater gains as new treatments for diabetes emerge.
Stay tuned for next week’s article on Type 2 diabetes and please share your thoughts in the comments section below.