Nanoparticles help researchers deliver steroids to retina

Dec 13, 2011

Hitching a ride into the retina on nanoparticles called dendrimers offers a new way to treat age-related macular degeneration and retinitis pigmentosa. A collaborative research study among investigators at Wayne State University, the Mayo Clinic and Johns Hopkins Medicine shows that steroids attached to the dendrimers targeted the damage-causing cells associated with neuroinflammation, leaving the rest of the eye unaffected and preserving vision.

The principal authors of the study, Raymond Iezzi, M.D. (Mayo Clinic ophthalmologist) and Rangaramanujam Kannan, Ph.D. (faculty of ophthalmology at The Wilmer Eye Institute of Johns Hopkins) have developed a clinically relevant, targeted, sustained-release using a simple nanodevice construct. The experimental work in rat models was initiated and substantially conducted at Wayne State University, and showed that one intravitreal administration of the nanodevice in microgram quantities could offer neuroprotection at least for a month, and appears in the journal, Biomaterials (33(3), 979-988).

Both dry age-related macular degeneration and retinitis pigmentosa are caused by neuroinflammation, which progressively damages the retina and can lead to blindness. Macular degeneration is the primary cause of vision loss in older Americans, affecting more than 7 million people, according to the National Institutes of Health (NIH). encompasses many genetic conditions affecting the retina and impacts 1 in 4,000 Americans, the NIH estimates.

"There is no cure for these diseases, said Iezzi. "An effective treatment could offer hope to hundreds of millions of patients worldwide. We tested the dendrimer delivery system in rats that develop neuroinflammation leading to . The target was activated microglial cells, the in charge of cleaning up dead and dying material in the eye. When activated, these cells cause damage via neuroinflammation — a hallmark of each disease."

" are tree-like, non-cytotoxic polymeric drug delivery vehicles (~ 4 nm). Surprisingly, the activated microglia in the degenerating retina appeared to eat the dendrimer selectively and retain them for at least a month. The drug is released from the dendrimer in a sustained fashion inside these cells, offering targeted neuroprotection to the retina," said Kannan.

The treatment reduced neuroinflammation in the rat model and protected vision by preventing injury to photoreceptors in the . Although the steroid offers only temporary protection, the treatment as a whole provides sustained relief from neuroinflammation, the study found. The researchers believe that this patent-pending technology with significant translational potential will be advanced further, through this multi-university collaboration among Johns Hopkins, Mayo Clinic and Wayne State. The study was funded by grants from the Ligon Research Center of Vision at Wayne State University, the Ralph C. Wilson Medical Research Foundation, Office of the Vice President for Research at Wayne State University, and Research to Prevent Blindness.

Explore further: Relaxing DNA strands by using nano-channels

Provided by Wayne State University

not rated yet
add to favorites email to friend print save as pdf

Related Stories

Scientists successfully awaken sleeping stem cells

Mar 18, 2008

Scientists at Schepens Eye Research Institute have discovered what chemical in the eye triggers the dormant capacity of certain non-neuronal cells to transform into progenitor cells, a stem-like cell that can generate new ...

Recommended for you

Relaxing DNA strands by using nano-channels

13 hours ago

A simple and effective way of unravelling the often tangled mass of DNA is to 'thread' the strand into a nano-channel. A study carried out with the participation of the International School for Advanced Studies ...

Сalculations with nanoscale smart particles

Aug 19, 2014

Researchers from the Institute of General Physics of the Russian Academy of Sciences, the Institute of Bioorganic Chemistry of the Russian Academy of Sciences and MIPT have made an important step towards ...

Attack Ebola on a nanoscale

Aug 15, 2014

(Phys.org) —The Ebola virus outbreak in West Africa has claimed more than 900 lives since February and has infected thousands more. Countries such as Nigeria and Liberia have declared health emergencies, ...

User comments : 0