In a recent study, researchers from Xi’an Jiaotong-Liverpool University and other universities in China have reported that brain stimulation combined with a nose spray containing nanoparticles can improve recovery after ischemic stroke in an animal model.
Rats that were given combined
nanoparticle and TMS treatment every 24 hours for 14 days after an ischemic
stroke had better overall health, put on weight more quickly and had improved
cognitive and motor functions compared to those treated with TMS alone.
MRI view of the rat brains: The dark spots pointed to
by red arrows and circled by red boxes indicate nanoparticles. The yellow arrow
shows the location of the permanent magnet placed on the skull to attract the
nanoparticles. (I.v., intravenous administration. i.n., intranasal
administration. Sample size for imaging is 5 male rats.) (Image credit: Dr Gang
Ruan.)
During TMS treatment, an electrical
current runs through an electric coil placed outside the skull, producing a
magnetic field that stimulates brain cells by inducing a further electrical
current inside the brain. However, the stimulation is often not intense enough
to penetrate far enough into the brain to reach the areas needing treatment.
In this new study, the researchers show that magnetic nanoparticles, administered intranasally, can make neurons more responsive and amplify the magnetic signal from TMS to reach deeper brain tissue, aiding recovery. The finding offers new opportunities for treating neurological disorders.
FROM IMPOSSIBLE TO POSSIBLE
The research answers a key question in
nanomedicine – whether it is possible to enhance TMS by using nanoparticles
that are non-invasively delivered into the brain. Leading figures in the field
previously stated that it was almost impossible because of the blood-brain
barrier. This physical barrier separates the brain from the rest of the body’s
bloodstream.
However, the team of researchers
overcame this by guiding the magnetic nanoparticles closer to the correct area
with a large magnet near the head.
Dr Gang Ruan, a corresponding author of
the study, says: “We were able to overcome the blood-brain barrier and send
enough nanoparticles into the brain to use in combination with TMS simulation
to improve recovery from stroke.
“TMS devices are already used for the
clinical treatment of neurological disorders but have severe limitations in
terms of stimulation strength and depths of the brain they can penetrate.
“By non-invasively putting magnetic
nanoparticles into the brain, we can amplify and enhance the TMS stimulation
effects on neurons, making the treatment more effective,” Dr Ruan adds.
“Showing it is possible to use nanoparticles in this way paves the way for medical applications of nanoparticles for other neurological disorders.”
CROSSING BARRIERS
The iron oxide nanoparticles used in the
study are already prescribed to treat iron deficiency as they are non-toxic and
biodegradable. The team also modified the nanoparticles by coating them with
various non-toxic substances.
Dr Ruan says: “The coating causes the
nanoparticles to stick to the blood-brain barrier, increasing their chances of
passing through it. Without this coating, the particles just bounce back from
the barrier instead of crossing it.
“The modifications of the iron oxide
particles also ensure that the nanoparticles can stick to the neurons and
increase their responsiveness to TMS stimulation.”
The safety of using the modified
nanoparticles needs to be assessed in clinical trials but has the potential to
be used in combination with TMS, and other methods such as brain imaging, to
gain more insight into how the brain works and improve the treatment of
neurological disorders.
“Many scientists still think it is
impossible to non-invasively send enough nanoparticles into the brain to affect
brain function. Yet we have shown that it is possible,” says Dr Ruan.
“We combined the expertise on our team in four different disciplines, materials science, biophysics, neuroscience, and medical science, to push the boundaries of our knowledge and challenge what is currently thought in the field.”
Source: https://www.xjtlu.edu.cn/en/news/2022/09/nanoparticles-can-improve-stroke-recovery-study-shows
Journal article: https://www.sciencedirect.com/science/article/abs/pii/S2468519422003330#fig5
No comments:
Post a Comment