Intravenous Multifunctional Nanotherapy for Treating Dry Age-Related Macular Degeneration

Area of Science:

• Ophthalmology
• Nanomedicine
• Biochemistry

Background:

• Dry age-related macular degeneration (dAMD) is characterized by retinal pigment epithelium (RPE) degeneration.
• Oxidative stress and mammalian target of rapamycin (mTOR) pathway activation are key drivers of RPE degeneration in dAMD.
• Current rapamycin treatments for dAMD show limited efficacy due to poor bioavailability and off-target effects.

Purpose of the Study:

• To develop a novel nanotherapy for dAMD that overcomes the limitations of existing treatments.
• To create a rapamycin-loaded, ROS-responsive micellar system for targeted delivery to damaged RPE cells.
• To evaluate the therapeutic potential of this nanotherapy in an in vivo model of RPE oxidative stress.

Main Methods:

• Development of APMNP@Rapa: a rapamycin-loaded, methionine-based, ROS-responsive polymeric micellar system functionalized with an Ab peptide for RPE targeting.
• Utilized poly(ethylene glycol)-poly-methionine copolymers for micelle self-assembly, leveraging methionine's biocompatibility and ROS-responsiveness.
• Tested APMNP@Rapa in a sodium iodate (NaIO3)-induced RPE oxidative stress model in mice.

Main Results:

• APMNP@Rapa demonstrated excellent circulation stability and biocompatibility.
• The nanotherapy effectively released rapamycin on-demand in the high-ROS microenvironment of diseased RPE.
• Simultaneous inhibition of mTOR activation, attenuation of oxidative damage, and suppression of inflammation were observed.
• Significant preservation of the retina against degradation was achieved in the dAMD model.

Conclusions:

• APMNP@Rapa represents a promising multifunctional nanotherapy for intravenous treatment of dAMD.
• This approach offers a new paradigm for simultaneously targeting oxidative stress and mTOR signaling in RPE degeneration.
• The developed ROS-responsive micellar system enhances drug delivery and therapeutic efficacy for retinal diseases.