Abstract
Purpose :
Age-Related Macular Degenration (AMD) is the leading cause of blindness in Europe, the USA and Australia. This study tested the hypothesis the hypothesis that targeting MFAP4 (which is upregulated at sites of vascular remodelling) would reduce choroidal vessel growth following laser induced choroidal neovascularisation in murine eyes.
Methods :
Female C57/Bl6 mice were anaesthetised and laser coagulation of the Bruch’s membrane was performed (Phoenix Micron IV retinal imaging microscope). Intraocular injection of either 1mg mouse IgG (DAKO) 1 or 5mg aMFAP4 or 1mg aVEGF. Injections were performed using a 36 Gauge Hamilton syringe, in a total of 2ml. Injections were performed at day 0 and day 7. Fundus Fluorescein Angiography (FFA) was performed on day 7 and day 14. Mice were culled and eyes excised, fixed in 4% paraformaldehyde. Choroids were dissected and immunostained for isolectin IB4 and CD45 and imaged by confocal microscopy. Quantification of lesion size, both of FFA and confocal data was performed using ImageJ.
Results :
aMFAP4 (1mg n=4), (5mg n=6)) reduced average lesion size and density (measured by FFA) by day 7 dose dependently (p<0.001 vs IgG control, n=8) whereas aVEGF (n=12) treatment required 2 doses to significantly reduce lesion size and density (n=4, p<0.05). IB4 staining of flatmounted choroids demonstrated reduced burn density following either aVEGF (n=4) or 5mg aMFAP4 (n=6) intraocular injection versus IgG injection (n=8). Inhibition of either VEGF (n=4), or MFAP4 (1mg, n=4 or 5mg n=6) was sufficient to significantly reduce CD45+ myeloid cell infiltration into the choroidal wound area (p<0.001).
Conclusions :
MFAP4 biology has not yet been studied in the eye, but our results are consistent with MFAP4 upregulation being upregulated by vascular injury (as seen in carotid intimal formation). Collectively this experiments suggest value in MFAP4 inhibition as a potential additional way to managed wet AMD.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.