The University of Rochester research helps to explain a disturbing trend noted by epidemiologists: that on smoggy days in urban areas, hospitals report a sharp rise in visits to emergency rooms for treatment of heart attacks.
In humans, disruption of the autonomic nervous system could lead to serious health risks, particularly for people who already have heart disease. Such disruptions are associated with arrhythmia, and sometimes forewarn an early death after a heart attack, said Alison Elder, Ph.D., lead author of the study and a research assistant professor in the Department of Environmental Medicine.
"The fact that exposure to air pollution can change the heart rate, independent of other factors, is a cause for concern," Elder said. "It's important to understand that these changes are taking place outside of the lung. Air pollution is either having a direct effect on the heart in rats or is altering something within the circulatory system."
The investigation began with the hypothesis that rats exposed to fresh vehicle emissions would show the same adverse outcomes that had been documented in a recent European study of humans. That study showed that people exposed to air pollution while riding in a bus or car or cycling to work were more likely to suffer a heart attack within one hour of their morning commute.
Rochester researchers placed aged hypertensive rats in a mobile laboratory for six hours on Interstate 90 in western New York for a total of 320 miles. The rats inhaled aerosols that any motorist would likely inhale on the same route. Researchers monitored the rats' blood pressure, heart rate and took electrocardiogram readings during the trip. Post-exposure recordings began 30 minutes after the trip and continued for five days.
Results showed a maximum drop in heart rate of 40 beats per minute, or a 10 percent decline. The effect persisted for up to 14 hours. In addition, researchers found a 70 percent decrease in the vagosympathetic balance, which is an index of heart rate variability and how the autonomic nervous system responds to change.
Studies such as this one are helping scientists understand why vehicle emissions, even at low levels, cause cardiovascular problems in addition to respiratory problems.
The biggest culprit seems to be the tiniest of air particles, known as ultrafines. They are 60,000 times more numerous than coarse particles found in air pollution. Ultrafines in ambient air are especially harmful because they mix with reactive gases and are taken deep into the lungs as aerosols. At that point, they may interact with the cells that line the blood vessels and enter the circulatory system.
Elder's group is the first to report a link between freshly generated engine emissions and changes in the rat autonomic nervous system, which controls the heart and other key organs.
The investigators are now looking at how on-road aerosols affect blood platelets, which could impact clotting and other essential circulatory functions, Elder said.
Leslie Orr | EurekAlert!
The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung
A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg
For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.
According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
23.01.2017 | Health and Medicine
23.01.2017 | Physics and Astronomy
23.01.2017 | Process Engineering