01.23.08
Posted in Atherosclerosis, Cardiology, Jacob Canon, MRI, Skalak, The Oscar Show, UVa College of Arts & Sciences, Uncategorized, University of Virginia, biomedical engineering, pharmaceutical, physical health at 12:12 pm by Jacob Canon
A new device invented by researchers at the University of Virginia could save pharmaceutical companies significant time and money in screening potential new drug compounds. Brett Blackman, an assistant professor in biomedical engineering and Brian Wamhoff, assistant professor in the department of medicine; cardiovascular division, teamed up to create a novel system, the HemoShear 2.0, which, for the first time, offers researchers the ability to observe the behavior patterns of human vascular cells under a variety of blood flow conditions that occur inside the body’s cardiovascular system.
The HemoShear 2.0 [6:29m]:
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Dr. Blackman said, “We want to help the pharmaceutical industry identify effective therapeutic compounds by allowing them to fail early, fail fast and fail cheap before going to very expensive animal studies.”
Atherosclerosis, hardening or narrowing of the arteries, is considered the most important underlying cause of heart attack or stroke. The HemoShear 2.0 models the early indicators of atherosclerosis by placing actual human endothelial cells, the cells lining the interior of blood vessels, and smooth muscle cells, the cells found in the wall of blood vessels, in an environment that mimics an artery with blood flowing through it. Data from these exposures are recorded and measured to help test the efficacy of therapeutic compounds and aid in early stage toxicity studies. Instead of testing drug compounds on isolated cells, which can produce false negatives, drug companies can use the device to test compounds in a more realistic environment.
This kind of modeling offers unique opportunities to observe the cells and their interaction. This interaction is important because the cells lining the interior of the blood vessels recognize different blood flow patterns imposed upon them and respond by expressing or repressing genes. This, in turn, influences their interactions with the cells found in the walls of blood vessels. The researchers found these cell interactions may lead to the onset of early-inflammation-associated atherosclerosis in certain arteries.
MRI’s were used by researchers to determine the rhythmic pattern that blood flows through different arteries in human subjects. Blackman said, “We are then able to simulate the same flow patterns in those areas that are more or less susceptible to atherosclerosis and observe how the cells respond to these flow patterns in HemoShear.”
Using a synthetic elastic layer that is similar to a real blood vessel wall, endothelial cells are plated on the top surface and smooth muscle cells on the bottom surface. Then, the different blood flow patterns modeled from human circulation are applied to the endothelial cells through rotation of a motor-driven cone system. The findings: the blood flow can influence both endothelial and smooth muscle cell behaviors.
When subjected to atheroprotective blood flow patterns, the endothelial cells aligned with the direction of the blood flow, and the smooth muscle cells aligned perpendicularly to the flow as is true in a healthy blood vessel. In stark contrast, the atheroprone type of flow caused the endothelial cells to move away from their parallel structure while smooth muscle cells moved away from their perpendicular structure.
This remodeling mimics the early phases of the diseased state of the artery; the blood flow pattern associated with atheroprone areas resulted in inflammation in both cells reminiscent of early hallmarks of atherosclerosis. This was confirmed through evaluating gene and protein expression profiles in both cell types.
Thomas Skalak, professor and chair of the U.Va. Department of Biomedical Engineering said, “the results of this study validate the use of this novel co-culture system as a relevant biomimetic vascular model for studying early atherosclerotic events. The cells’ responses to these carefully controlled models of blood flow can now be used to develop therapeutic interventions for detection and treatment of vascular diseases. It has the potential to be revolutionary.”
You’ve been listening to the Oscar Show, I’m Jacob Canon. Join us next week as we again delve into the election season, when our topic will be the work of Bryan Pfaffenberger, associate professor at the University of Virginia’s School of Engineering and Applied Science and his study of mechanical-lever voting machines, their history and understanding the interaction between technology and culture that has been going on for more than a century…
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11.22.07
Posted in Jacob Canon, James Coan, MRI, Psychology, Relationships, The Oscar Show, University of Virginia, anxiety, brain, emotions, environmental conditions, happiness, hypothalamus, immune, nervous system, neurobiology, neurophysiology, physical health, physiology, sensory inputs, stress at 3:46 pm by Jacob Canon
How did you react the last time you had a fight with that significant someone in your life? With couples, the woman might apologize, or the man might make a joke or express understanding. By doing this, they subtly and briefly lighten the tension as they work their way through a disagreement.
Psychology Professor James Coan discovered a long time ago that by doing this, even when couples fight, they take care of each other. This interplay was significant when Coan designed a study exploring what happens in people’s brains when they behave emotionally or observe other people’s emotions. Coan said, “what we are learning is our emotions are more heavily involved in our day-to-day physical health than we previously thought.
How we deal with our relationships is closely tied to how long we live, how frequently we go to the doctor, how rapidly we recover from injury, how happy we tend to be in our lives.” With his colleagues, Hillary Schaefer and Richard J. Davidson from the University of Wisconsin, Coan sought to demonstrate the neurobiological basis of emotional expression and regulatory processes.
In the study, they used MRI technology to view these responses at the level of glucose metabolism and blood oxygenation in the brain. Because of the importance of emotional connectedness to the study, 16 happily married, heterosexual couples were recruited as test subjects. Wives were placed in the scanner so brain activity could be recorded as each was exposed to the anxiety-producing possibility of an electric shock to the ankle.
Researchers wanted to see what effect different types of emotional support would have in areas of the brain related to the body’s normal fight-or-flight stress response. Readings were taken when the woman was alone in facing this challenge, When a stranger, a male, was present to support her And when her husband offered support. Coan stated, “the scanning environment is pretty hostile to looking at interactions between people.” The MRI machine surrounds the subject’s body and restricts movement. The women weren’t even able to see the support person during the scanning process.
Having the man offer his hand for the woman to hold was about the only intervention possible in this setting. Not surprisingly, the results show there was a healthy reduction in the stress response when test subjects were supported. Stimulation in the regions of the brain that regulate physiological arousal and coordinate large muscles and joints was significantly decreased, no matter who was holding the woman’s hand. However, when it was her husband’s hand she was holding, the response was significantly greater.
Coan said, “When you’re holding a spouse’s hand, you get down-regulation in all of those same systems. But all the other systems that have to do with the conscious regulation of your emotions — having to pay attention to what’s happening with your body and having to become more vigilant for future dangers — all of these other systems come down as well. Your brain doesn’t work as hard when it’s your spouse. What surprised Coan and his colleagues most was the relaxation response demonstrated by what they called “super couples.” In those couples with exceptionally high-quality relationships, “Hand-holding had a significantly greater effect on soothing their brains.”
Tests showed differences involving two structures that were not affected at all in other test subjects. They observed evidence of reduced release of stress hormones by the hypothalamus. These hormones are responsible for inhibiting immune response and other activities that have critical implications for health and well-being.
Of greater interest was the reduction of activity in the right anterior insula. This brain structure modulates the amount of pain stimulus one experiences subjectively. Reduction of activity in this area means test subjects actually felt less pain when they held their husband’s hand.
So it can be said, having someone you love hold your hand really can take the hurt away.
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