I Spy for Heart Disease

Aug. 29, 2014

By Medical Discovery News

Heart in chest

While a shrink ray like the kind used in science fiction is still stuck in the future, miniature devices are not. Tiny devices have been created to perform a variety of tasks, from an implantable telescope to improve vision in those with macular degeneration to the new pacemaker in clinical trials that is about the size of a large vitamin pill. Now, researchers have developed a catheter-based device smaller than the head of a pin that can provide real-time 3D images of the heart, coronary arteries, and other blood vessels. This is an important invention as the casualties of heart disease continue to rise. Statistically, one in four people will have a heart attack. 

Many Americans are at risk for developing coronary artery disease (CAD) due to the buildup of cholesterol and plaque. If there is a rupture or breakage of the plaque, creating a blood clot, that can result in a heart attack with little to no warning. Traditional diagnostic tests such as stress tests and echocardiograms show how much blood is flowing to the heart. If there are regions of the heart that are not getting as much blood as others, it might be a sign of clogged coronary arteries. However, blood flow can also appear to be normal even with plaque buildup.

Currently, there are a variety of methods that provide images of what is going on inside arteries, including magnetic resonance imaging (MRI), multi-detector Computerized Tomography (CT) scans, and injecting an iodine-based contrast agent into arteries through a catheter. But all these look at the inside of the body from the outside, which is why this new device gives an unprecedented way of viewing the heart.

This invention combines ultrasound imaging with computer processors on a single chip only 1.4 millimeters wide. The body’s signals are processed on the chip then transmitted through 13 tiny cables to a computer monitor, so doctors have a visual of the heart and arteries. The prototype took 60 images per second using very little power, therefore generating little heat. This would allow cardiologists to take real-time images of blood vessels in and around the heart to more precisely determine the extent of blockages. These images also have much higher resolution compared to those taken with machines outside the body.

The next step is to conduct studies using the device on animals to determine its safety and efficacy and to develop potential applications of this technology. Eventually, this data will be submitted to the Food and Drug Administration (FDA) to gain permission to perform clinical trials on humans. Extensive testing will be required before the FDA will approve the device for general use. The developers, a group of engineers at the Georgia Institute of Technology, are also working to shrink the device even further to .4 millimeters so it can generate images of even smaller blood vessels.

Having clearer images of blood vessels would allow surgeons to have a more complete understanding of the blockage they are dealing with before they operate. Hopefully, in the future use of this device will prevent heart attacks and save many people’s lives.

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Bear-ly Understanding Diabetes

May 30, 2014

By Medical Discovery News

What can studying grizzly bears reveal about human diabetes?

While they are some of the largest bears on earth, Grizzly bears aren’t usually accused of being fat. Regardless, these animals are helping scientists discover new and better treatments for human obesity and diabetes.

Grizzlies spend the late summers consuming more than 50,000 calories per day. As a comparison, a moderately active 50-year-old human female is recommended 2,300. Grizzlies then hibernate for up to seven months, relying on the pounds of stored fat they accumulated before winter. While hibernating, bears do not eat, urinate, or defecate. 

Scientists wondered if all the weight and fat bears gain results in diabetes like it does in humans. Overweight people face an increased risk of type 2 diabetes, in which the body does not make enough of the hormone insulin or cells do not respond to it. Insulin helps move a type of sugar called glucose from the blood into cells, where it is used for energy and as a precursor for other molecules the body needs. If sugar levels in the blood remain elevated and the body doesn’t have enough insulin, cells are starved for energy, leading to damaged eyes, kidneys, nerves, and hearts. 

Interestingly, Grizzly bears can actually control their insulin responsiveness. When they are the fattest, they are most sensitive to insulin, thereby keeping their blood sugar levels healthy. Soon after going into hibernation, they switch to complete insulin resistance, meaning they develop type 2 diabetes. But unlike humans, their blood sugar levels remain normal. When they awaken in the spring, their insulin responsiveness is restored. Bears do this not so much to regulate their blood sugar levels as to regulate their storage and utilization of fat. So how do bears control their insulin responsiveness? And could it lead to new treatments for type 2 diabetes in humans?

PTEN is a protein that regulates cells’ sensitivity to insulin. Scientists know exactly when Grizzlies increase or decrease PTEN activity, they just don’t know how. People with a PTEN mutation have a metabolism similar to Grizzlies’.  These people have an increased risk of obesity and cancer but a decreased risk of developing type 2 diabetes because they are more sensitive to insulin.

Grizzlies have also evolved to the ability to accumulate large amounts of fat only in their adipose tissue, just below the skin so it doesn’t interfere with the rest of their bodies. In humans, on the other hand, fat can accumulate in many places like the liver, in muscles, and around other internal organs, which are all highly unhealthy places to keep fat. Bears can also have elevated levels of cholesterol without the serious consequences of cardiovascular disease.

During hibernation, the Grizzly bears’ kidneys shut down. But despite the high levels of toxins that accumulate in the blood without working kidneys, they don’t die or even suffer from it like a human would. When they wake up, their kidney function is restored with no permanent damage.

After millions of years of evolution, Grizzly bears and other animals have developed solutions for biological challenges humans still face. Studying them is a new approach that has the potential to create treatments for many human conditions.

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