Features | Partner Sites | Information | LinkXpress
Sign In
GLOBETECH PUBLISHING
GLOBETECH PUBLISHING
JIB

Acoustic Pressure Helps Deliver Drugs to the Brain

By BiotechDaily International staff writers
Posted on 26 Aug 2014
Image: Fluorescence images of the murine hippocampus after diffusion of Dextran through the FUS opened BBB (Left), compared to contralateral that shows no uptake (Right) (Photo courtesy of Dr. Elisa Konofagou/ Columbia University).
Image: Fluorescence images of the murine hippocampus after diffusion of Dextran through the FUS opened BBB (Left), compared to contralateral that shows no uptake (Right) (Photo courtesy of Dr. Elisa Konofagou/ Columbia University).
A new technique uses a focused ultrasound (FUS) beam to control the size of molecules penetrating the blood-brain barrier (BBB).

Researchers at Columbia University (New York, NY, USA) conducted a study that applied FUS onto a mouse hippocampus in the presence of systemically administered microbubbles (MBs) containing fluorescently labeled dextrans with molecular weights of 3-2,000 kDa (2.3–54.4 nm in diameter), to examine the possibility of trans-BBB dextran delivery. Outcomes were evaluated using ex vivo fluorescence imaging, and cavitation detection was employed to concomitantly monitor the MB activity associated with the delivery of the dextrans.

The results showed that FUS-induced BBB opening size—defined by the size of the largest molecule that can permeate through the BBB—can be controlled by acoustic pressure. BBB opening size was smaller than 3 kDa (2.3 nm) at 0.31 MPa, reached 70 kDa (10.2 nm) at 0.51 MPa, and was as large as 2,000 kDa (54.4 nm) at 0.84 MPa. Relatively smaller opening size (up to 70 kDa) was achieved with stable cavitation only; however, inertial cavitation was associated with relatively larger BBB opening size (above 500 kDa). The study was published in the July 2014 issue of the Journal of Cerebral Blood Flow & Metabolism.

“Most small and all large molecule drugs do not currently penetrate the blood-brain barrier that sits between the vascular bed and the brain tissue,” said study coauthor professor of biomedical engineering and radiology Elisa Konofagou, PhD, of Columbia Engineering. “This is an important breakthrough in getting drugs delivered to specific parts of the brain precisely, noninvasively, and safely, and may help in the treatment of central nervous system diseases like Parkinson's and Alzheimer's.”

FUS in conjunction with MBs—gas-filled bubbles coated by protein or lipid shells—is so far the only technique can permeate the BBB safely and noninvasively. When MBs are hit by an FUS beam, they start oscillating due to cavitation, the formation of vapor cavities in the liquid phase; depending on the magnitude of the pressure, they continue oscillating or collapse. The study showed that the pressure of the FUS can be adjusted depending on the size of the drug that needs to be delivered to the brain - small molecules at lower pressures and larger molecules at higher pressures.

Related Links:

Columbia University



comments powered by Disqus

Channels

Genomics/Proteomics

view channel
Image: Differences in the structure of a small lung artery (top row) and heart cross section (lower row) of rodents without disease (far left column); with pulmonary hypertension (middle) and a diseased rodent treated with the HDL peptide (right). Note the much narrowed lung artery, and thick walls and larger chamber of the heart in the diseased animal and improvements with 4F peptide treatment (Photo courtesy of UCLA - University of California, Los Angeles).

Apolipoprotein A-1 Mimetic Peptide Reverses Pulmonary Hypertension in Rodent Models

A small peptide that mimics the activity of apolipoprotein A-1 (apo A-1), the main protein component of the high density lipoproteins (HDL), counteracted the effects of oxidized lipids and alleviated symptoms... Read more

Drug Discovery

view channel
Image: (Left) Neurons in brains from people with autism do not undergo normal pruning during childhood and adolescence. The images show representative neurons from unaffected brains (left) and brains from autistic patients (right); the spines on the neurons indicate the location of synapses (Photo courtesy of Guomei Tang, PhD and Mark S. Sonders, PhD, Columbia University Medical Center).

Autistic Youngsters Found to Have Too Many Brain Synapses

Autistic children and adolescents have been shown to have an excess of brain synapses, and this is due to a slowdown in the normal brain “trimming” process during development, according to new findings.... Read more

Therapeutics

view channel
Image: Hair follicle (blue) being attacked by T cells (green) (Photo courtesy of Christiano Lab/Columbia University Medical Center).

Hair Restoration Method Clones Patients’ Cells to Grow New Hair Follicles

Researchers have developed of a new hair restoration approach that uses a patient’s cells to grow new hair follicles. In addition, the [US] Food and Drugs Administration (FDA) recently approved a new drug... Read more

Lab Technologies

view channel

Important Immune Cell Regulators’ Response Identified

A new strategy could help accelerate laboratory research and the development of potential therapeutics, including vaccines. The technology may also be used to identify the genes that underlie tumor cell development. There are approximately 40,000 genes in each of the body’s cells, but functions for only approximately... Read more

Business

view channel

Partnership Established to Decode Bowel Disease

23andMe (Mountain View, CA,USA), a personal genetics company, is collaborating with Pfizer, Inc. (New York, NY, USA), in which the companies will seek to enroll 10,000 people with inflammatory bowel disease (IBD) in a research project designed to explore the genetic factors associated with the onset, progression, severity,... Read more
 
Copyright © 2000-2014 Globetech Media. All rights reserved.