Doug Melton, a world renowned stem cell researcher at Harvard University may have discovered a cure to Type 1 Diabetes last year.
Generation of function human pancreatic beta cells in vitro
The generation of insulin-producing pancreatic b cells from stem cells in vitro would provide an unprecedented cell source for drug discovery and cell transplantation therapy in diabetes. However, insulin-producing cells previously generated from human pluripotent stem cells (hPSC) lack many functional characteristics of bona fide b cells. Here, we report a scalable differentiation protocol that can generate hundreds of millions of glucose-responsive b cells from hPSC in vitro. These stem-cell-derived b cells (SC-b) express markers found in mature b cells, flux Ca2+ in response to glucose, package insulin into secretory granules, and secrete quantities of insulin comparable to adult b cells in response to multiple sequential glucose challenges in vitro. Furthermore, these cells secrete human insulin into the serum of mice shortly after transplantation in a glucose-regulated manner, and transplantation of these cells ameliorates hyperglycemia in diabetic mice.
Before I go any further, let me unpack that first sentence. In simple terms, stem cells are a type of cell found in the human body, that, when told, can become basically any cell in the body—muscle, liver, skin etc. Doug Melton and the scientists in his lab have been working to see if they can make a cell in vitro(in a petri dish) that can do what normal pancreas beta cells do. The pancreas is an organ that is important for regulating the amount of sugar that circulates in your blood stream, among other things. The beta cells of the pancreas make and release a hormone(chemical signal) known as insulin. This hormone tells the cells in your body to take extra glucose(sugar) out of your bloodstream for storage and use at a later time. This is important, you don’t want your body to use too much sugar because that could lead to excessive weight gain, type 2 diabetes and more. Which brings me to my next point, there are two kinds of diabetes patients. Those that have type 1 have a pancreas that is unable to make insulin, while those that have type 2 have bodies that don’t respond to insulin (insulin resistant). A healthy pancreas maintains your blood sugar levels and when it doesn’t work properly you can develop diabetes.
So let’s review: Doug Melton’s lab has been looking for a way to make cells that produce insulin as a solution to type 1 diabetes.
This paper is the summary of the series of experiments they conducted that led them to create insulin producing beta cells, which has never been done before. Researchers have been able to make beta cells, but they weren’t able to get them to function the way healthy beta cells do. In total they tested 70 different cell signals in 150 different combinations before they landed on the magic one. They discovered that if you take a stem cell and surround it with 11 cell signals, in a specific order you can make a functional beta cell. It’s kind of like making chilly, but with cell signaling chemicals(these are natural chemical produced by your body) and it takes 4-5 weeks. The best kinds of chilly are cooked slowly, and the ingredients are added in a certain order, at a specific time.
To test how well the cells work, they used mice that were genetically engineered to be type 1 diabetics. They made beta cells, injected them into the mice, and then tested their blood sugar levels under different conditions. They found less blood sugar, and amounts of insulin that are comparable to insulin levels in most healthy adults. Essentially, those mice were temporarily cured of their type 1 diabetes as soon as they were injected.
A few concerns: The beta cells they created did have some differences compared to normal beta cells and it’s not totally clear that the same effects seen in mice will be seen in people. Mice are a good way to study disease, but they aren’t always predictive of what will happen when you try the same experiments on humans. They don’t know how long the effects of the injected beta cells will last in humans. You may have to inject someone every day, every week, every month—you don’t know. You probably won’t permanently cure someone with just one injection. Where is the best place to inject these cells? How many cells does each patient need to see positive results? How expensive will this be? How scalable is this? Meaning, will there be a bank of stem cells where scientists will be converting them into beta cells 24/7? Can we get enough stem cells to treat everyone with type 1 diabetes? Will you use the patient’s cells or someone else’s cells?
There are still so many questions to be answered, but that doesn’t take away from how important this discovery is. We are closer to a cure for type 1 diabetes, but there are a few kinks that need to be dealt with first.
*Disclaimer: I do not claim to be an expert on the aforementioned topic and do not take any credit for the work, discoveries or materials discussed herein.