Wednesday, November 30, 2016

Restoring Insulin Secretion

Can nonfunctioning beta cells be rejuvenated? Researchers from Florida State University think they can.

In a paper published in PLOS Computational Biology, the researchers, led by Richard Bertram, postulate that it's oscillating pulses of glucose that cause the oscillating pulses of insulin that are seen in healthy people. In nondiabetics, insulin isn't secreted continuously but in pulses, and it's been known for some time that this pulsatile insulin release is lost in people with type 2 diabetes. But no one knew why.

These researchers used sophisticated technology and mathematical modeling to come up with a new model, a Dual Oscillator Model (this type of model has been used in other research, for example, in understanding circadian rhythms here and here). They first put beta cells from mice in a high-glucose environment and found that they lost the pulsatile insulin secretion. Then by using their techniques to manipulate the glucose levels in ways suggested by the mathematical modeling, they were able to resuscitate the beta cells so that they produced insulin again in a healthy pulsatile way.

This technique is nowhere near the stage at which it could be used clinically to cure type 2 diabetes. But it's exciting because it suggests that a type 2 cure is possible, at least in those with viable beta cells. Those cells apparently aren't dead; they're just not functioning properly.

The authors' model is described in detail in their paper, the full text of which is free online. It's fairly dense and mathematical. They found that in response to glucose, some beta cells produce electrically driven fast oscillations in calcium levels, and other produce metabolically driven slow oscillations. They suggest that these two types of cells cooperate to produce pulsatile insulin secretion.

Clearly, creating conditions in vivo that would replicate the results found in their "microfluidic device" would not be simple. But the more we understand about how beta cells operate, the better. And their finding that continuously high glucose levels caused the beta cells to lose their oscillating insulin pulses is another indication that the standard Western lifestyle with too many calories as well as too many carbohydrate foods is not a good idea. Many close relatives of people with type 2 diabetes lack oscillating insulin pulses, suggesting a high risk of progressing to full-blown diabetes.

Maybe this new way of looking things will help us to find at-risk people in the very early stages, when their condition can be truly reversed.

Monday, November 28, 2016

Adolescent weight gain

An interesting study has shown that resting energy expenditure in adolescents is lower than in older or younger people. This means that they'll burn fewer calories when resting, leaving more available for growth and weight gain.

I found this fascinating because I was a normal-weight child but became "chubby" at about 11 or 12 and then lost weight with no change in lifestyle when I was about 16. Other family members showed the same pattern.

I'm always interested in why something happens, and in this case the authors hypothesize that because growth requires a lot of energy, the body tackles the problem of rapid growth in adolescence by making adolescents be more energy efficient, so they get more calories from the same amount of food.  In a society in which food was scarce, this would be the only way those rapidly growing bodies could get enough calories to build the new tissues they needed.

When growth is complete, the body stops being so efficient with its digestion as the extra calories are no longer needed, and the metabolism increases again. 

However, in our world, where food is usually easily available, turning down the metabolism during adolescence may lead to obesity that doesn't reverse when growth is complete.

This pattern of decreased metabolism only during adolescence is obviously not universal. Some people were chubby children and others don't slim down in their late teens when growth is complete.

However, it's an example of the fact that weight gain and loss are not always a result of voluntary food choices. Sometimes Mother Nature is nudging us in one direction or the other.

Wednesday, November 9, 2016

Trump and Diabetes

One of Donald Trump's goals as President is to repeal the Affordable Care Act, often referred to as "Obamacare."

I can understand why many are upset about the fact that it's expensive. Good health care is expensive, and Medicare isn't free either.

But one of the mandates in Obamacare is that insurers can't penalize people for having preexisting conditions. Before that, it was almost impossible for people without health insurance who had already been diagnosed with diabetes to get any health insurance at all.

If Obamacare is repealed, does this mean millions of people with diabetes will suddenly find themselves with no insurance and no possibility of getting replacement insurance?

It's a scary thought.