A significant problem in treating disease which affect the
brain is that getting medicine into the brain tissue is very difficult. This is
due to the ‘blood-brain-barrier’ which prevents medicines in the bloodstream
from crossing over into the brain tissue. This is a unique feature of the brain,
as other organs (kidneys, liver, lungs, etc.) readily absorb medicines from the
blood stream. A simple method to overcome this barrier is to simply dose the
medicine so high that even if a small portion of the drug crosses into the
brain it is effective. However, this strategy does not work with medicines that
have side-effects at high doses. Another method of dealing with this problem is
to generate medicine-loaded nanoparticles which are specifically modified in such
a way as to allow them to penetrate across the blood-brain barrier so they can
deliver medicine into the brain for treatment of neural diseases. Recently,
researchers working jointly at University of Southern Denmark (Denmark) and
Instituto de Investigacao e Inovacao em Saude (Portugal) utilized PLGA-PEG-NH2
from PolySciTech (www.polyscitech.com)
(PolyVivo AI058) to generate transferrin decorated nanoparticles for
blood-brain-barrier penetration. This research holds promise for improved
delivery of medicine to brain tissue for improved treatment of cancer or neural
disease such as alzeheimers. Read more: Gomes, Maria Joao, Patrick J. Kennedy,
Susana Martins, and Bruno Sarmento. "Delivery of siRNA silencing P-gp in
peptide-functionalized nanoparticles causes efflux modulation at the
blood–brain barrier." Nanomedicine 0 (2017). http://www.futuremedicine.com/doi/abs/10.2217/nnm-2017-0023
“Aim: Explore the use of transferrin-receptor
peptide-functionalized nanoparticles (NPs) targeting blood–brain barrier (BBB)
as siRNA carriers to silence P-glycoprotein (P-gp). Materials & methods:
Permeability experiments were assessed through a developed BBB cell-based
model; P-gp mRNA expression was evaluated in vitro; rhodamine 123 permeability
was assessed after cell monolayer treatment with siRNA NPs. Results: Beyond
their ability to improve siRNA permeability through the BBB by twofold, 96-h
post-transfection, functionalized polymeric NPs successfully reduced P-gp mRNA
expression up to 52%, compared with nonfunctionalized systems. Subsequently,
the permeability of rhodamine 123 through the human BBB model increased up to
27%. Conclusion: Developed BBB-targeted NPs induced P-gp downregulation and
consequent increase on P-gp substrate permeability, revealing their ability to
modulate drug efflux at the BBB.”
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