Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nanoparticles reboot blood flow in brain

24.08.2012
Rice University, Baylor College of Medicine discovery might aid emergency care of traumatic brain-injury victims
A nanoparticle developed at Rice University and tested in collaboration with Baylor College of Medicine (BCM) may bring great benefits to the emergency treatment of brain-injury victims, even those with mild injuries.

Combined polyethylene glycol-hydrophilic carbon clusters (PEG-HCC), already being tested to enhance cancer treatment, are also adept antioxidants. In animal studies, injections of PEG-HCC during initial treatment after an injury helped restore balance to the brain’s vascular system.

The results were reported this month in the American Chemical Society journal ACS Nano.

A PEG-HCC infusion that quickly stabilizes blood flow in the brain would be a significant advance for emergency care workers and battlefield medics, said Rice chemist and co-author James Tour.

“This might be a first line of defense against reactive oxygen species (ROS) that are always overstimulated during a medical trauma, whether that be to an accident victim or an injured soldier,” said Tour, Rice’s T.T. and W.F. Chao Chair in Chemistry as well as a professor of mechanical engineering and materials science and of computer science. “They’re certainly exacerbated when there’s trauma with massive blood loss.”

In a traumatic brain injury, cells release an excessive amount of an ROS known as superoxide (SO) into the blood. Superoxides are toxic free radicals, molecules with one unpaired electron, that the immune system normally uses to kill invading microorganisms. Healthy organisms balance SO with superoxide dismutase (SOD), an enzyme that neutralizes it. But even mild brain trauma can release superoxides at levels that overwhelm the brain’s natural defenses.

“Superoxide is the most deleterious of the reactive oxygen species, as it’s the progenitor of many of the others,” Tour said. “If you don’t deal with SO, it forms peroxynitrite and hydrogen peroxide. SO is the upstream precursor to many of the downstream problems.”

SO affects the autoregulatory mechanism that manages the sensitive circulation system in the brain. Normally, vessels dilate when blood pressure is low and constrict when high to maintain an equilibrium, but a lack of regulation can lead to brain damage beyond what may have been caused by the initial trauma.

“There are many facets of brain injury that ultimately determine how much damage there will be,” said Thomas Kent, the paper’s co-author, a BCM professor of neurology and chief of neurology at the Michael E. DeBakey Veterans Affairs Medical Center in Houston. “One is the initial injury, and that’s pretty much done in minutes. But a number of things that happen later often make things worse, and that’s when we can intervene.”

Kent cited as an example the second burst of free radicals that can occur after post-injury resuscitation. “That’s what we can treat: the further injury that happens because of the necessity of restoring somebody’s blood pressure, which provides oxygen that leads to more damaging free radicals.”

In tests, the researchers found PEG-HCC nanoparticles immediately and completely quenched superoxide activity and allowed the autoregulatory system to quickly regain its balance. Tour said ROS molecules readily combine with PEG-HCCs, generating “an innocuous carbon double bond, so it’s really radical annihilation. There’s no such mechanism in biology.” While an SOD enzyme can alter only one superoxide molecule at a time, a single PEG-HCC about the size of a large protein at 2-3 nanometers wide and 30-40 nanometers long can quench hundreds or thousands. “This is an occasion where a nano-sized package is doing something that no small drug or protein could do, underscoring the efficacy of active nano-based drugs.”

“This is the most remarkably effective thing I’ve ever seen,” Kent said. “Literally within minutes of injecting it, the cerebral blood flow is back to normal, and we can keep it there with just a simple second injection. In the end, we’ve normalized the free radicals while preserving nitric oxide (which is essential to autoregulation). These particles showed the antioxidant mechanism we had previously identified as predictive of effectiveness.”

The first clues to PEG-HCC’s antioxidant powers came during nanoparticle toxicity studies with the MD Anderson Cancer Center. “We noticed they lowered alkaline phosphatase in the liver,” Tour said. “One of our Baylor colleagues saw this and said, ‘Hey, this looks like it’s actually causing the liver cells to live longer than normal.’

“Oxidative destruction of liver cells is normal, so that got us to thinking these might be really good radical scavengers,” Tour said.

Kent said the nanoparticles as tested showed no signs of toxicity, but any remaining concerns should be answered by further tests. The researchers found the half-life of PEG-HCCs in the blood – the amount of time it takes for half the particles to leave the body – to be between two and three hours. Tests with different cell types in vitro showed no toxicity, he said.

The research has implications for stroke victims and organ transplant patients as well, Tour said.

Next, the team hopes to have another lab replicate its positive results. “We’ve repeated it now three times, and we got the same results, so we’re sure this works in our hands,” Kent said.

First authors of the paper are BCM graduate student Brittany Bitner, Rice graduate student Daniela Marcano and former Rice postdoctoral researcher Jacob Berlin, now an assistant professor of molecular medicine at the Beckman Research Institute of the City of Hope, Duarte, Calif. Co-authors are all at BCM: Roderic Fabian, associate professor of neurology; Claudia Robertson, professor of neurosurgery; Leela Cherian, research instructor of neurosurgery; Mary Dickinson, associate professor of molecular physiology; Robia Pautler, associate professor of molecular physiology; and James Culver, a graduate student in molecular physiology.

The research was funded by the Department of Defense’s Mission Connect Mild Traumatic Brain Injury Consortium, the National Science Foundation, the National Institutes of Health and the National Heart, Lung and Blood Institute.

Read the abstract at http://pubs.acs.org/doi/abs/10.1021/nn302615f

David Ruth | EurekAlert!
Further information:
http://www.rice.edu

More articles from Life Sciences:

nachricht Tag it EASI – a new method for accurate protein analysis
20.06.2018 | Max-Planck-Institut für Biochemie

nachricht How to track and trace a protein: Nanosensors monitor intracellular deliveries
19.06.2018 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Creating a new composite fuel for new-generation fast reactors

20.06.2018 | Materials Sciences

Game-changing finding pushes 3D-printing to the molecular limit

20.06.2018 | Materials Sciences

Could this material enable autonomous vehicles to come to market sooner?

20.06.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>