Written by Joyce Smith, BS. A six-month supplementation with omega-3 and -6 or omega-3 alone significantly contributed to retinal regeneration in a mouse model of dry AMD.
Age-related macular degeneration (AMD) affects 200 million people worldwide and is the leading cause of visual impairment and blindness in the elderly. 1 An estimated 50% more elderly will have AMD by 2040 2. Loss of the central field of vision characterizes both “dry”(atrophic) and “wet”(neovascular) types of AMD. They differ in that dry AMD affects 80-90% of individuals with AMD, has slower progression and is characterized by yellow retinal deposits that cause deterioration and loss of vision over time. Common to wet AMD is abnormal vascularization under the retina and bleeding into it which can lead to rapid vision loss and blindness. Once dry AMD progresses to the advanced stage, there is presently no available treatment to prevent further vision loss 3; however, several anti-oxidants, vitamins and zinc may reduce its progression 4.
Administration of PUFAs was previously found to have a promising effect in several animal models of macular degeneration 5. Several studies have demonstrated that omega-3 PUFAs may have a protective role in retinal pathologies 6. A recent multi-center, double-blind, placebo-controlled study assessed the effect of oral omega-3 fatty acids (1680 mg eicosapentaenoic acid [EPA] and 560 mg docosahexaenoic acid [DHA]) in patients with dry eyes, and found a significant improvement in several parameters of eye health, including tear osmolarity and tear break-up time 7. In addition, a 2017 observational study by Georgiou and Prokopiou demonstrated a significant improvement in vision (≥15 letters gain) in patients with dry AMD following a 6-month supplementation with EPA and DHA (5–7.5 g/day and arachidonic acid (AA)/EPA<2) 8. In the study, Prokopiou et al investigated the effects of omega-3 alone or in combination with omega-6 fatty acids in mice with dry AMD while monitoring their blood levels of EPA and arachidonic acid AA (AA/EPA=1–1.5). Age-matched (9-month old) mice with dry AMD were randomized to four groups of 22-24 per group and euthanized after three months of receiving (10 mL/kg) of fish oil via lavage.
| Group A Wild Mice | Group B AMD Mice | Group C AMD Mice | Group D AMD Mice |
|---|---|---|---|
| Untreated | Untreated | Omega-3 and -6 (100 mg EPA+50mg DHA) + 30 mg y-linolenic acid (GLA) | omega-3 (130 mg EPA) |
Compared to the untreated AMD mice and wild mice, the combination omega 3-6 group revealed a trend towards increased retinal levels of EPA (p<0.0001) and a significant decrease in AA (p<0.0001). Histological examination of retinas revealed significantly higher DHA levels in both fish oil treatment groups (p<0.0001); however, the retinal photoreceptors’ outer layers had higher levels of omega-3 than omega-6 (p<0.001, p<0.05 respectively) suggesting a greater reduction in retinal neovascularization in the omega3 group. Inflammatory cytokine production was lower in both treatment groups.
Supplementation with omega-3 and -6 or omega-3 alone (when AA/EPA=1–1.5) offered protection in the mice with AMD, and a more beneficial effect was observed when Omega-3 was used alone. These findings indicate that inflammation is not the only determining factor in dry AMD and suggest that omega-3 fatty acids may have participated in a regenerative process. While these results suggest a potential therapy for AMD, additional research is warranted to gain a better understanding of omega-3’s protective effect.
Source: Prokopiou, Ekatherine, Panagiotis Kolovos, Maria Kalogerou, Anastasia Neokleous, Gregory Papagregoriou, Constantinos Deltas, Stavros Malas, and Tassos Georgiou. “Therapeutic potential of omega-3 fatty acids supplementation in a mouse model of dry macular degeneration.” BMJ Open Ophthalmology 1, no. 1 (2017): e000056.
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Posted March 20, 2018.
Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.
References:
- Friedman DS, O’Colmain BJ, Munoz B, et al. Prevalence of age-related macular degeneration in the United States. Arch ophthalmol. 2004;122(4):564-572.
- Wong WL, Su X, Li X, et al. Global prevalence of age-related macular degeneration and disease burden projection for 2020 and 2040: a systematic review and meta-analysis. The Lancet Global Health. 2014;2(2):e106-e116.
- Lylas G. Mogk MD. The Difference Between Wet and Dry Age-Related Macular Degeneration. [web article]. http://www.visionaware.org/info/your-eye-condition/age-related-macular-degeneration-amd/wet-and-dry-amd/125.
- Group A-REDSR. A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E and beta carotene for age-related cataract and vision loss: AREDS report no. 9. Archives of Ophthalmology. 2001;119(10):1439.
- Tuo J, Ross RJ, Herzlich AA, et al. A high omega-3 fatty acid diet reduces retinal lesions in a murine model of macular degeneration. The American journal of pathology. 2009;175(2):799-807.
- SanGiovanni JP, Chew EY. The role of omega-3 long-chain polyunsaturated fatty acids in health and disease of the retina. Progress in retinal and eye research. 2005;24(1):87-138.
- Epitropoulos AT, Donnenfeld ED, Shah ZA, et al. Effect of oral re-esterified omega-3 nutritional supplementation on dry eyes. Cornea. 2016;35(9):1185.
- Georgiou T, Prokopiou E. The new era of omega-3 fatty acids supplementation: therapeutic effects on dry age-related macular degeneration. Journal of stem cells. 2015;10(3):205.
