(NaturalNews) Diesel exhaust smells nasty, looks filthy and can make you cough. But there's an even more important reason to avoid the pollutant that's spouted from countless buses and cars: diesel exhaust is linked to the growth of cancerous tumors. Now researchers at Ohio State University have discovered how diesel fumes can spur on malignancies -- diesel exhaust causes new blood vessels to grow that serve as a food supply for cancerous tumors.
The scientists experimented with mice by creating two
conditions that mimic conditions in a
human body exposed to diesel fumes. One group of lab rodents was implanted with tiny platforms seeded with normal endothelial cells (the cells that line
blood vessels) under their skin. The mice in another group were manipulated so there was ischemia (a loss of
blood flow) to their hind limbs and that generated an area of severe hypoxia (lack of oxygen), a condition found in many diseases.
Then, for six hours per day five days a week, both groups of mice were exposed to either
diesel exhaust or filtered outdoor air. The rest of the time the
animals breathed filtered indoor air. The
scientists measured the effects of these these exposures after two weeks, five weeks and eight weeks.
The results of the experiment, which were just published online and are slated to be included in the upcoming print edition of the journal
Toxicology Letters, show diesel fumes act like a kind of fuel for blood vessels. Compared to mice breathing filtered air, an eight week
exposure to diesel exhaust caused a six-fold increase in new blood vessel formation in the ischemic hind limbs and a four-fold increase in vessel formation in the mice with normal hind legs. The scientists also found more blood vessel growth in the implanted normal cells.
In all, the
research team discovered that three types of blood vessel development had taken place areas after exposure to the diesel exhaust: angiogenesis, the development of new capillaries; arteriogenesis, the maturation or re-started growth of existing vessels; and vasculogenesis, the formation of new blood vessels.
These findings are significant -- and worrisome -- because all of these processes are associated with the growth of cancerous tumors. And it is runaway angiogenesis that especially wreaks havoc in the human body, helping malignancies spread. What's more, the exhaust exposure levels in the study were designed to mimic the diesel fume exposure that humans regularly receive if they reside in cities and/or commute in heavy traffic. In a statement to the media, the research team pointed out that the tiny size of inhaled diesel particles (most are less than 0.1 microns in diameter) allow the material to penetrate into the human circulatory system, organs and tissues, potentially causing damage anywhere in the body.
"The message from our study is that exposure to diesel exhaust for just a short time period of two months could give even normal tissue the potential to develop a tumor," Qinghua Sun, senior author of the study and an assistant professor of environmental
health sciences at Ohio State University, said in the media release.
"We need to raise public awareness so people give more thought to how they drive and how they live so they can pursue ways to protect themselves and improve their health. And we still have a lot of work to do to improve diesel engines so they generate fewer particles and exhaust that can be released into the ambient air."
NaturalNews previously reported on additional research that shows diesel fumes could trigger cardiovascular problems, too. Diesel toxins interact with fatty acids found in LDL ("bad") cholesterol to raise the risk of heart
disease, according to a study published in the online journal
Genome Biology (
http://www.naturalnews.com/022198.html).
Editor's note: NaturalNews is opposed to the use of animals in medical experiments that expose them to harm. We present these findings in protest of the way in which they were acquired.
For more information:http://researchnews.osu.edu/archive/depexposure.htm
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