Retinal spectral domain optical coherence tomography in early atrophic age-related macular degeneration (AMD) and a new metric for objective evaluation of the efficacy of ocular nutrition

VEGF-R2/CAV-1 Interaction Induced by Resveratrol/Eicosapentaenoic Acid/Docosahexaenoic Acid-Enriched Formulation through Functional Detergent-Resistant Membranes Is Associated with Decreased VEGF-A Release in ARPE-19 Cells

SCOPE

Omega-3 fatty acids (O3FAs) and resveratrol (RSV) are known to be beneficial for certain eye diseases, such as age-related macular degeneration (AMD). Neovascular AMD is characterized by abnormal blood vessel formation due to the excessive synthesis of vascular endothelial growth factor (VEGF) by retinal pigment epithelium (RPE) cells. The study investigates whether a formulation based on eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and RSV is capable of counteracting VEGF-A secretion, and elucidates the molecular mechanism.

METHODS AND RESULTS

The study finds, using ELISA, that O3FAs/RSV reduces VEGF-A secretion in human RPE cells. This phenomenon is related to the increased interaction between VEGF-receptor 2 (VEGF-R2) and caveolin-1 (CAV-1), a protein of detergent-resistant membranes (DRMs), as determined by co-immunoprecipitation and proximity ligation assay. Using microscale thermophoresis, the study confirms that O3FAs/RSV causes a high-affinity interaction. Isolation and analysis of DRMs reveal that this interaction is concomitant with VEGF-R2 relocalization in DRMs. The depletion of DRMs by a cholesterol-chelating agent blocks the VEGF-R2/CAV-1 interaction and EPA/DHA/RSV-mediated impairment of VEGF production.

CONCLUSION

This specific interaction can provide a new strategy for countering VEGF-A production in human RPE cells and, consequently, reducing neovascularization in AMD. Further preclinical studies involving O3FAs and polyphenols are warranted.

Resvega, a Nutraceutical Preparation, Affects NFκB Pathway and Prolongs the Anti-VEGF Effect of Bevacizumab in Undifferentiated ARPE-19 Retina Cells

Age-related macular degeneration (AMD) is an irreversible chronic degenerative pathology that affects the retina. Despite therapeutic advances thanks to the use of anti-vascular endothelial growth factor (VEGF) agents, resistance mechanisms have been found to accentuate the visual deficit. In the present study, we explored whether a nutraceutical formulation composed of omega-3 fatty acids and resveratrol, called Resvega®, was able to disrupt VEGF-A secretion in human ARPE-19 retina cells. We found that Resvega® inhibits VEGF-A secretion through decreases in both the PI3K-AKT-mTOR and NFκB signaling pathways. In NFκB signaling pathways, Resvega® inhibits the phosphorylation of the inhibitor of NFκB, IκB, which can bind NFκB dimers and sequester them in the cytoplasm. Thus, the NFκB subunits cannot migrate to the nucleus where they normally bind and stimulate the transcription of target genes such as VEGF-A. The IκB kinase complex (IKK) is also affected by Resvega® since the nutraceutical formulation decreases both IKKα and IKKβ subunits and the IKKγ subunit which is required for the stimulation of IKK. Very interestingly, we highlight that Resvega® could prolong the anti-angiogenic effect of Avastin®, which is an anti-VEGF agent typically used in clinical practice. Our results suggest that Resvega® may have potential interest as nutritional supplementation against AMD.

Retinal Structure in Pre-Clinical Age-Related Macular Degeneration

PURPOSE

To determine, if there are identifiable retinal structural changes associated with genetic risk for age-related macular degeneration (AMD).

MATERIALS AND METHODS

Seventy-three subjects (range 51.5 to 68.9 years) participated in this prospective study. Subjects were recruited based on the presence of a family history of AMD in one or both parents. All participants underwent a complete ophthalmic exam and imagery for staging of disease severity and genetic testing to assess genetic risk for AMD development. Optical coherence tomography (OCT) imaging was performed on all participants. Semi-automated retinal layer segmentation was performed to assess retinal structural changes.

RESULTS

Of 73 subjects, 47 subjects had normal appearing retina with no evidence of drusen or other changes consistent with AMD, 16 subjects were classified as early AMD, and 13 were designated as intermediate AMD. Retinal volume measures of total retina, outer retina, outer nuclear layer and the retinal pigment epithelium, were not related to AMD classification, genetic risk scores, or age. The thickness of the outer retina showed statistically significant thickening in the foveal region in only the intermediate AMD group and a statistically significant thickening of the RPE in early and intermediate AMD groups in the central retina.

CONCLUSION

No consistent changes were observed in retinal structure at multiple locations that are associated with pre-clinical AMD, based on AMD genetic risk or with aging within the age range of our cohort.