Lipidomic analysis revealed n-3 polyunsaturated fatty acids suppressed choroidal thinning and myopia progression in mice

Metabolomic profiling of ocular tissues in rabbit myopia: Uncovering differential metabolites and pathways

To investigate the metabolic difference among tissue layers of the rabbits' eye during the development of myopia using metabolomic techniques and explore any metabolic links or cascades within the ocular wall. Ultra Performance Liquid Chromatography - Mass Spectrometry (UPLC-MS) was utilized for untargeted metabolite screening (UMS) to identify the significant differential metabolites produced between myopia (MY) and control (CT) (horizontal). Subsequently, we compared those key metabolites among tissues (Sclera, Choroid, Retina) of MY for distribution and variation (longitudinal). A total of 6285 metabolites were detected in the three tissues. The differential metabolites were screened and the metabolic pathways of these metabolites in each myopic tissue were labeled, including tryptophan and its metabolites, pyruvate, taurine, caffeine metabolites, as well as neurotransmitters like glutamate and dopamine. Our study suggests that multiple metabolic pathways or different metabolites under the same pathway, might act on different parts of the eyeball and contribute to the occurrence and development of myopia by affecting the energy supply to the ocular tissues, preventing antioxidant stress, affecting scleral collagen synthesis, and regulating various neurotransmitters mutually.

Choroidal thickness in relation to diopter and axial length among myopic children

Purpose

The aim of this study was to analyze the relationship between diopter (D) and choroidal thickness in myopic children by describing the values of choroidal thickness, and explore choroidal thickness as an important indicator for evaluating the progression of myopia.

Methods

The study included myopic and emmetropic children aged 6-14 years (156 eyes) from the Second Hospital of Dalian Medical University. The participants were divided into four groups according to the spherical equivalent refraction (SER): low myopes, moderate myopes, high myopes, and emmetropes. Choroidal thickness was measured in nine areas using the Early Treatment Diabetic Retinopathy Study (ETDRS) grid layout, which divided the areas into concentric circles of 0 × 0 mm, 3 × 3 mm, and 5 × 5 mm from the Sub Fovea. The images were obtained manually with spectral-domain optical coherence tomography scanner.

Results

There were significant differences of choroidal thickness in the nine areas of the ETDRS grid for all myopes. The distribution of choroidal thickness in low and moderate myopes were different from that in high myopes. In the horizontal direction, choroidal thickness decreased from the temporal to nasal areas for all myopes. In the vertical direction, the choroidal thickness in the perifovea was smaller than that in the parafovea (SER ≥ -2.75D), and the choroidal thickness in the perifovea was greater than that in the parafovea (SER < -2.75D). When comparing emmetropes with myopes, the closer the choroidal thickness was to the central fovea, the more significant the differences were, while the differences were smaller to the perifovea. Among all children, choroidal thickness was positive to SER and negative to axial length (AL) in all areas. For every 1D increase in myopia, the subfoveal choroidal thickness decreased by 13 μm, and for every 1 mm increase in AL, the subfoveal choroidal thickness decreased by 23 μm. Furthermore, SER and AL showed the strongest correlation with choroidal thickness in the inferior area.

Conclusion

Optical coherence tomography results revealed choroidal thickness was thinner in myopic children. Choroidal thickness was positive to SER and negative to AL. Therefore, we consider choroidal thickness to be an important indicator for evaluating the myopia progress.

Long chain acyl-CoA synthetase 6 facilitates the local distribution of di-docosahexaenoic acid- and ultra-long-chain-PUFA-containing phospholipids in the retina to support normal visual function in mice

Docosahexaenoic acid (DHA) and ultra-long-chain polyunsaturated fatty acids (ULC-PUFAs) are uniquely enriched in membrane phospholipids of retinal photoreceptors. Several studies have shown that di-DHA- and ULC-PUFA-containing phospholipids in photoreceptors have an important role in maintaining normal visual function; however, the molecular mechanisms underlying the synthesis and enrichment of these unique lipids in the retina, and their specific roles in retinal function remain unclear. Long-chain acyl-coenzyme A (CoA) synthetase 6 (ACSL6) preferentially converts DHA into DHA-CoA, which is a substrate during DHA-containing lipid biosynthesis. Here, we report that Acsl6 mRNA is expressed in the inner segment of photoreceptor cells and the retinal pigment epithelial cells, and genetic deletion of ACSL6 resulted in the selective depletion of di-DHA- and ULC-PUFA-containing phospholipids, but not mono-DHA-containing phospholipids in the retina. MALDI mass spectrometry imaging (MALDI-MSI) revealed the selective distribution of di-DHA- and ULC-PUFA-containing phospholipids in the photoreceptor outer segment (OS). Electroretinogram of Acsl6-/- mice exhibited photoreceptor cell-derived visual impairment, whereas the expression levels and localization of opsin proteins were unchanged. Acsl6-/- mice exhibited an age-dependent progressive decrease of the thickness of the outer nuclear layers, whereas the inner nuclear layers and OSs were normal. These results demonstrate that ACSL6 facilitates the local enrichment of di-DHA- and ULC-PUFA-containing phospholipids in the retina, which supports normal visual function and retinal homeostasis.

Association of n-3 polyunsaturated fatty acid intakes with juvenile myopia: A cross-sectional study based on the NHANES database

Aim

Inflammation is involved in the development of myopia. n-3 polyunsaturated fatty acids (n-3 PUFAs) have vasodilating and anti-inflammatory effects, which may be involved in controlling myopia. It is of great significance to explore the relationship between n-3 PUFA intakes and juvenile myopia in order to control and alleviate myopia among teenagers through dietary intervention.

Methods

Sociodemographic data, information of nutrient intakes, cotinine, PUFAs, and eye refractive status of 1,128 juveniles were extracted from the National Health and Nutrition Examination Survey (NHANES) database in this cross-sectional study. PUFAs contained total polyunsaturated fatty acid (TPFAs), alpha-linolenic acid, octadecatetraenoic acid, eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA). Covariates were screened by comparison among groups of normal vision, low myopia, and high myopia. The association between n-3 PUFA intakes and the risk of juvenile myopia was evaluated using univariate and multivariate logistic regression analyses with odds ratios (ORs) and 95% confidence intervals (CIs).

Results

Among the juveniles, 788 (70.68%) had normal vision, 299 (25.80%) had low myopia, and 41 (3.52%) had high myopia. There were significant differences in average EPA and DHA intakes among the three groups, and mean DPA and DHA intakes in the normal vision group were lower than those in the low myopia group (P < 0.05). After adjustment for age, gender, TPFAs, and cotinine, a high dietary intake of EPA (≥11 mg/1,000 kcal) in juveniles seemed to be associated with the risk of high myopia (OR = 0.39, 95% CI: 0.18-0.85), while no significant associations were identified between n-3 PUFA intakes and the risk of low myopia.

Conclusion

A high dietary intake of EPA may be associated with a decreased risk of high myopia among juveniles. A further prospective study is needed to validate this observation.

Potential Properties of Natural Nutraceuticals and Antioxidants in Age-Related Eye Disorders

Eye health is crucial, and the onset of diseases can reduce vision and affect the quality of life of patients. The main causes of progressive and irreversible vision loss include various pathologies, such as cataracts, ocular atrophy, corneal opacity, age-related macular degeneration, uncorrected refractive error, posterior capsular opacification, uveitis, glaucoma, diabetic retinopathy, retinal detachment, undetermined disease and other disorders involving oxidative stress and inflammation. The eyes are constantly exposed to the external environment and, for this reason, must be protected from damage from the outside. Many drugs, including cortisonics and antinflammatory drugs have widely been used to counteract eye disorders. However, recent advances have been obtained via supplementation with natural antioxidants and nutraceuticals for patients. In particular, evidence has accumulated that polyphenols (mostly deriving from Citrus Bergamia) represent a reliable source of antioxidants able to counteract oxidative stress accompanying early stages of eye diseases. Luteolin in particular has been found to protect photoreceptors, thereby improving vision in many disease states. Moreover, a consistent anti-inflammatory response was found to occur when curcumin is used alone or in combination with other nutraceuticals. Additionally, Coenzyme Q10 has been demonstrated to produce a consistent effect in reducing ocular pressure, thereby leading to protection in patients undergoing glaucoma. Finally, both grape seed extract, rich in anthocyanosides, and polynsatured fatty acids seem to contribute to the prevention of retinal disorders. Thus, a combination of nutraceuticals and antioxidants may represent the right solution for a multi-action activity in eye protection, in association with current drug therapies, and this will be of potential interest in early stages of eye disorders.