Ultrafijnstof slecht voor hersenfuncties*
Uit eerdere studies is al gebleken dat utrafijnstof afkomstig van vervuilde lucht, veelal door dieseluitlaatgassen, ook in de hersenen terecht kan komen. Uit deze
Nederlandse studie o.l.v. professor Borm van het Centre of Expertise Life Sciences (CEL) van de
Hogeschool Zuyd te Heerlen blijkt dat ultrafijnstof ook oxidatieschade in de hersenen veroorzaakt en daardoor de hersenfuncties beïnvloedt. Binnen een half uur na blootstelling aan ultrafijnstof beginnen informatieprocessen in de hersenschors te veranderen.
(De hersenschors is het gebied in de hersenen, waar informatie uit de rest van het lichaam ontvangen, geanalyseerd en geïnterpreteerd wordt. Vervolgens wordt deze geïnterpreteerde informatie in de cortex weer omgezet in gedachten en concrete aansturingen van het lichaam.) Ook na de blootstelling houden deze veranderingen nog minstens 1 uur aan. De gebruikte hoeveelheden ultrafijnstof zijn te vergelijken met hoeveelheden die gevonden worden in straten met druk verkeer of bijv. een garage.
Just one hour of exposure to diesel exhaust fumes induces a stress response in brain
If the smell of diesel exhaust isn't enough to make you avoid getting a lungful, new research now shows that even a short exposure to the fumes can affect your brain.
A study published in the open access journal Particle and Fibre Toxicology reveals that an hour of sniffing exhaust induces a stress response in the brain's activity.
Previous studies have already suggested that very small particles, called nanoparticles, breathed in from polluted air can end up in the brain. But this is the first time that scientists have demonstrated that inhalation actually alters brain activity.
Ten volunteers spent one hour in a room filled with either clean air or exhaust from a diesel engine. They were wired up to an electroencephalograph (EEG), a machine that records the electrical signals of the brain, and their brain waves were monitored during the exposure period and for one hour after they left the room.
The researchers found that after about 30 minutes the diesel exhaust began to affect brain activity. The EEG data suggested that the brain displayed a stress response, indicative of changed information processing in the brain cortex, which continued to increase even after the subjects had left the exposure chamber.
The concentration of diesel exhaust that the subjects breathed was set to the highest level that people might encounter in the environment or at work, for example on a busy road or in a garage.
Lead researcher Paul Borm from Zuyd University in The Netherlands said: "We believe our findings are due to an effect nanoparticles or 'soot' particles that are major component of diesel exhaust. These may penetrate to the brain and affect brain function. We can only speculate what these effects may mean for the chronic exposure to air pollution encountered in busy cities where the levels of such soot particles can be very high."
One link to understanding the mechanism of this effect is that oxidative stress is one consequence of particles depositing in tissue and oxidative stress has also been implicated in degenerative brain diseases such as Parkinson's and Alzheimer's disease . "It is conceivable that the long-term effects of exposure to traffic nanoparticles may interfere with normal brain function and information processing," noted Borm. "Further studies are necessary to explore this effect, and to assess the relationship between the amount of exposure to particles and the brain's response and, and investigate the clinical implications of these novel findings."
Studies that expose volunteers to potential toxins or require invasive techniques are limited for ethical reasons. Borm is currently conducting experiments where volunteers inhale artificially generated nanoparticles that are free from the other chemicals that are generated, along with the nanoparticles in diesel
exhaust. http://www.biomedcentral.com/ (Mei
2008)
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