On Monday, Lisa and I were at a Memorial Day picnic with a bunch of Grinnell alums. As it happens, the party’s host does a lot of research with transgenic, or “knockout” mice. These furry little guys have had part of their DNA modified so they express genes associated with specific diseases or physiological traits. Researchers then try novel therapies on the transgenic mice (as well as a control group) to see if they can cure—or cause—disease. It’s fascinating stuff, and it’s the kind of thing that is helping to cure diabetes.
Diabetes came up during our conversation about knockout mice, since they’re so common in diabetes research. “People aren’t mice,” I noted. “How relevant are mouse models to human disease research?” It turns out mice are (for the most part) very good models for cancer research, because the things that affect cancer cell growth and disease progression—cellular mutations, vasculature, immune signaling, etc.—are comparatively simple and thus more likely to be similar between mice and humans. Diabetes, as an endocrine system disorder of (currently) uncertain origin, is much more complicated than cancer. There’s some evidence that—in addition to genetics and a viral pathogen—diet and the kind of bacteria in gut flora might trigger (or inhibit) the autoimmune reaction which kills pancreatic beta cells. Basically, because it’s a lot more complex than having a mutation in a particular gene, triggering diabetes later in life.
Diabetes is one of those cases where the mouse model turns out to be different from human physiology in significant and subtle ways. I mentioned some recent research which showed that the same gene that’s linked to type-2 diabetes in mice is actually protective against it in humans.
“Curing diabetes in mice is like falling off a log. I can do it in my sleep,” our host said.
And I think this is at the heart of why it’s worth taking a (mouse-sized?) grain of salt when hearing about therapies that “cure” diabetes in mice. These mice are vital to the research, of course, but the results have to be verified in human trials. And therein lies the rub, since there’s a sizable jump in complexity between our furry friends and us. One thing is clear, though: Without that initial research using transgenic mice, we’d be a lot farther behind than where we are today. So let’s hear it for those little guys!