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Novel Model Heart Will Measure Health Impacts of Various Nanoparticles

by Editor1 last modified September 07, 2011 - 14:12

German researchers have created a new heart model could serve as a test organ to help determine the health impacts of select artificial nanoparticles. The team is from the Helmholtz Zentrum Muenchen and the Technische Universität Muenchen.

Novel Model Heart Will Measure Health Impacts of Various Nanoparticles

The researchers adopted a Langendorff heart, which is an isolated rodent heart flushed with a nutrient solution in place of blood. The test organ was adopted to let investigators study the impact of nanoparticles on the heart as a whole organ for the first time, said Professor Reinhard Niessner, Director of the Institute of Hydrochemistry at the TU Muenchen.

"We use the heart as a detector [to] test whether specific nanoparticles have an effect on the heart function,” Prof. Niessner said. Researchers also have a measurement setup that can be used to analyze the effects of nanoparticles on a complete, intact organ without being influenced by the reactions of other organs, he added.

The modified Langendorff heart is a particularly good test object, members of the team said. "It has its own impulse generator, the sinus node, enabling it to function outside the body for several hours," noted Andreas Stampfl of Helmholtz Zentrum München’s Institute of Toxicology and Institute of Health Economics & Healthcare Management.

The team also explored the mechanisms by which nanoparticles can influence heart rate, Prof. Niessner added. Specifically, they modified the Langendorff heart to allow the nutrient solution to be fed back into the loop after it had flowed through the heart. The results reveal it is very likely that the neurotransmitter noradrenaline is responsible for the increased heart rate brought on by nanoparticles, the found. "Changes in the heart function can be clearly recognized using the heart rate and ECG chart," Stampfl added.

In their preliminary research, the research team showed some artificial nanoparticles have a measurable effect on the heart, causing an increased heart rate, cardiac arrhythmia and modified ECG values typically found in patients with heart disease.

In specific, the team found carbon black, spark-generated carbon, titanium dioxide and silicon dioxide led to an increase in the heart rate of up to 15 percent. Carbon black is a widely used nanoparticle (mainly in car tires and plastics) with over 8 million tons produced annually. Their size at only 14 nanometers across makes them well suited as dyes, e.g. in printers and copying machines.

These nanoagents also produced altered ECG values that did not normalize, even after the nanoparticle exposure was ended. Noradrenaline is released by nerve endings in the inner wall of the heart. It increases the heart rate and also plays an important role in the central nervous system – a tip-off that nanoparticles might also have a damaging effect there.

On the other hand, the team also found aerosil silicas and polystyrene did not show any effect on the heart function.

This new heart model may prove to be particularly useful in medical research and could serve as a test organ to help select nanoparticles that do not affect the heart in a negative way.

In light of the increasing demand for artificial nanoparticles in medicine and industry, it is important for manufacturers to understand just how these particles influence bodily functions and which mechanisms are at play – questions to which there has been a dearth of knowledge.

“The next thing we want to do is to find out why some nanoparticles influence the heart function, while others do not influence the heart at all,” Prof. Niessner added. Both manufacturing process and shape may play an important role. Hence, the scientists plan further studies to examine the surfaces of different types of nanoparticles and their interactions with the cells of the cardiac wall.