How the eye recycles the vitamin A visual pigment with a retinyl ester enzyme

Studies of retinyl ester hydrolase in the visual cycle

['FUNDING_R01'] · WAKE FOREST UNIVERSITY HEALTH SCIENCES · NIH-11116966

This work looks at whether the enzyme PNPLA2 helps the eye recycle the vitamin A–based pigment that keeps vision working, which could matter for people with visual cycle–related retinal problems.

Quick facts

Phase['FUNDING_R01']
Study typeNih_funding
SexAll
SponsorWAKE FOREST UNIVERSITY HEALTH SCIENCES (nih funded)
Locations1 site (WINSTON-SALEM, UNITED STATES)
Trial IDNIH-11116966 on ClinicalTrials.gov

What this research studies

Researchers will examine PNPLA2 in retinal pigment epithelial (RPE) cells and lipid droplets to understand how retinyl ester (the stored form of vitamin A in the eye) is moved to the part of the cell where visual pigment is remade. They will use PNPLA2 knockout mice, lab-grown cell experiments, electroretinography to measure retinal function, and biochemical tests of pigment regeneration. Early mouse data show that loss of PNPLA2 reduces ERG responses and delays pigment recovery, suggesting it helps normal vision. The team may also use AAV viral delivery to replace PNPLA2 in cells to see if restoring the enzyme improves pigment recycling and retinal responses.

Who could benefit from this research

Good fit: People with inherited or acquired retinal disorders that impair the visual cycle or RPE function, or those willing to donate tissue for retinal research, would be most relevant.

Not a fit: People whose vision loss is due to optic nerve damage, refractive errors, or retinal conditions that do not involve the visual cycle are unlikely to benefit directly.

Why it matters

Potential benefit: If successful, this work could point to new treatments that improve pigment regeneration and help protect or restore vision in people with visual cycle disorders.

How similar studies have performed: There is precedent for targeting visual-cycle enzymes—RPE65 gene therapy has helped some patients—while targeting PNPLA2 is a novel approach supported so far by promising animal data.

Where this research is happening

WINSTON-SALEM, UNITED STATES

Researchers

About this research

  1. This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
  2. Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
  3. For full project details, budget, and progress reports, visit the official NIH RePORTER page below.

View on NIH RePORTER →

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.