A research group led by Associate Professor Toru Nakazawa at Tohoku University Graduate School of Medicine and a group led by Professor Mitsuru Akashi at Graduate School of Engineering, Osaka University have jointly demonstrated a new medication for retinal disorders in animal testing using γPGA nanoparticles.

 Local or systematic steroid administration is typical for diabetic retinopathy, central retinal vein occlusion and uveitis in ocular disorder treatment.  Steroid has often been used in clinical practice for its medical benefits.  However, chronic steroid administration has been known to be difficult due to unintentional side effects, such as osteoporosis, diabetes, hypertension, hyperlipidemia, glaucoma, cataract and neurotoxicity.  Therefore, research and development of Drug Delivery System (DDS) has been promoted to selectively carry drugs to specific cells or tissues in order to reduce side effects.  γPGA nanoparticles have gathered attention for its effective property as drug carrier, and a research for application to ophthalmologic field has been conducted.

 In this study, it was found out that γPGA nanoparticles were carried only to phagocytic cells (macrophage or microglia), which cause damage to retina cells,  after the particles were given to eyes of laboratory rats with ocular disorders.  Nanoparticles containing steroid gradually release it in cells and continually suppress phagocytic cell activation to protect retinal ganglion or visual cells. 

 The research result shows the following: 1) γPGA nanoparticles selectively deliver drugs to phagocytic cells (DSS) and 2) nanoparticles containing steroid slowly release drugs and maintain the effect of administration (slow drug release).  Intraocular drug administration using γPGA nanoparticles could be a new medication with less side effects.

 The research result was published online in Journal of Controlled Release on January 5, 2011.  The paper’s title is “Suppression of phagocytic cells in retinal disorders using amphiphilic poly (γ-glutamic acid) nanoparticles containing dexamethasone.”

More Information (Japanese)

[Contact]
Associate Professor Toru Nakazawa
Advanced Ophthalmic Medicine,
Tohoku University Graduate School of Medicine
TEL: +81-22-717-7294
E-mail: ntoru*oph.med.tohoku.ac.jp (Replace * with @)

(Public Relations)
Associate professor Fuji Nagami
Public Relations Office of Tohoku University Graduate School of Medicine
TEL +81-22-717-7908, FAX: +81-22-717-8187
E-mail: f-nagami*med.tohoku.ac.jp (Replace * with @)