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Functional recovery after experimental RPE debridement, mfERG studies in a porcine model
Nina Buus Sørensen1, Nathan Lassota, Maria Voss Kyhn
1Department of Ophthalmology, Glostrup Hospital, University of Copenhagen, Copenhagen, Denmark, nina.sorensen@dadlnet.dk.
Background:
The correlation between histologically identified regeneration of retinal pigment epithelium (RPE) and functional outcome measured by multifocal electroretinography (mfERG) following surgical debridement is examined in a porcine model. In humans, visual acuity is reduced in diseases with RPE loss such as RPE tears and geographic atrophy. Hypopigmented RPE is known to cover the lesion after RPE debridement in the pig, but it is unclear whether this leads to a return of photoreceptor function.
Methods:
RPE debridement was performed in ten pigs by vitrectomy and retinotomy, and by brushing the Bruch's membrane with a silicone catheter. Immediately following surgery (baseline) and after 2 and 6 weeks respectively, the animals were examined by mfERG, fundus photographs (FPs), fluorescein angiograms (FAs), and histopathology.
Results:
The mfERG P1 amplitude was decreased 2 weeks (T₂) after surgery; it returned to baseline 6 weeks (T₆) after surgery. FPs, FAs, and histology showed partial repopulation of Bruch's membrane by hypopigmented RPE cells and atrophied outer segments at T₂. At T₆, normally pigmented RPE cells were identified, and the photoreceptor layer was restored.
Conclusion:
This is the first study to show that the histological regeneration of hypopigmented RPE correlates to a return of the retinal function, measured by mfERG.
Insights
Histological regeneration of the retinal pigment epithelium (RPE) in pigs after debridement surgery correlated with restored photoreceptor function, as measured by multifocal electroretinography (mfERG). This indicates RPE regeneration can lead to functional recovery.
Area of Science:
- Ophthalmology
- Regenerative Medicine
- Retinal Science
Background:
- Retinal pigment epithelium (RPE) loss in humans causes reduced visual acuity in conditions like RPE tears and geographic atrophy.
- The functional outcome of RPE regeneration after surgical debridement is not well understood.
- Hypopigmented RPE observed post-debridement in porcine models raises questions about photoreceptor function restoration.
Purpose of the Study:
- To examine the correlation between histological RPE regeneration and functional recovery measured by multifocal electroretinography (mfERG).
- To investigate the return of photoreceptor function following RPE debridement in a porcine model.
Main Methods:
- Surgical RPE debridement was performed in ten pigs.
- Animals underwent mfERG, fundus photography, fluorescein angiography, and histopathology at baseline, 2 weeks, and 6 weeks post-surgery.
- Bruch's membrane was debrided using a silicone catheter via vitrectomy and retinotomy.
Main Results:
- mfERG P1 amplitude decreased at 2 weeks but returned to baseline by 6 weeks post-surgery.
- Histopathology at 2 weeks revealed hypopigmented RPE and atrophied outer segments.
- At 6 weeks, normally pigmented RPE cells and restored photoreceptor layers were observed.
Conclusions:
- This study demonstrates a correlation between histological RPE regeneration and the return of retinal function.
- The findings suggest that RPE regeneration, even if initially hypopigmented, can lead to functional recovery.
- This is the first study to link histological RPE regeneration with mfERG-measured functional recovery in a debridement model.
