Negative effects of transthyretin in high myopic vitreous on diabetic retinopathy

The relationship between refractive error and the risk of diabetic retinopathy: a systematic review and meta-analysis

Purpose

This meta-analysis was conducted to collect all available data and estimate the relationship between refractive error and the risk of diabetic retinopathy (DR) in patients with diabetes, and to assess whether vision-threatening DR (VTDR) is associated with refractive error.

Methods

We systematically searched several literature databases including PubMed, Embase, Cochrane Library, Web of Science, CNKI, CBM, Wan Fang Data, and VIP databases. Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated using fixed or random effects models. Four models were developed to assess the relationship between refractive error and the risk and DR, VTDR: hyperopia and DR, VTDR; myopia and DR, VTDR; spherical equivalent (SE per D increase) and DR, VTDR; and axial length (AL per mm increase) and DR, VTDR. The included literature was meta-analyzed using Stata 12.0 software, and sensitivity analysis was performed. Publication bias in the literature was evaluated using a funnel plot, Begg's test, and Egger's test.

Results

A systematic search identified 3,198 articles, of which 21 (4 cohorts, 17 cross-sectional studies) were included in the meta-analysis. Meta-analysis showed that hyperopia was associated with an increased risk of VTDR (OR: 1.23; 95% CI: 1.08-1.39; P = 0.001), but not with DR (OR: 1.05; 95% CI: 0.94-1.17; P = 0.374). Myopia was associated with a reduced risk of DR (OR: 0.74; 95% CI: 0.61-0.90; P = 0.003), but not with VTDR (OR: 1.08; 95% CI: 0.85-1.38; P = 0.519). Every 1 diopter increase in spherical equivalent, there was a 1.08 increase in the odds ratio of DR (OR: 1.08; 95% CI: 1.05-1.10; P<0.001), but not with VTDR (OR: 1.05; 95% CI: 1.00-1.10; P = 0.06). AL per mm increase was significantly associated with a decreased risk of developing DR (OR: 0.77; 95% CI: 0.71-0.84; P<0.001) and VTDR (OR: 0.63; 95% CI: 0.56-0.72; P<0.001). Analysis of sensitivity confirmed the reliability of the study's findings.

Conclusion

This meta-analysis demonstrates hyperopia was associated with an increased risk of VTDR in diabetes patients. Myopia was associated with a reduced risk of DR. AL is an important influencing factor of refractive error. Every 1 mm increase in AL reduces the risk of DR by 23% and the risk of VTDR by 37%.

Systematic review registration

identifier: CRD42023413420.

The interface targeting hnRNPA2B1 regulates the repression of transthyretin against human retinal microvascular endothelial cells in high-glucose environment

BACKGROUND

The interaction between transthyretin (TTR) and heterogeneous nuclear ribonucleoprotein (hnRNP)A2B1 is involved in the neovascularization of human retinal microvascular endothelial cells (hRECs) under hyperglycemic conditions. However, whether the TTR-hnRNPA2B1 interface can be altered and how this protein-protein interaction and associated downstream pathways are regulated is unclear.

METHODS

We performed homologous sequential analysis and binding energy assays using Discovery Studio and designed substitution targeting three fragments of the interface (fragment 1: aa 34-39, -RKAADD-; fragment 2, aa 61-68, -EEEFVEGI-; and fragment 3, aa 96-102, -TANDSGP-) to disrupt or stabilize the TTR-hnRNPA2B1 complex and were subjected to Co-immunoprecipitation analysis. To investigate the effect of TTR-hnRNPA2B1 interface alterations on the physiological properties of hRECs, we performed CCK-8, EdU, migration, wound healing and tube formation assays. To study the downstream genes, we performed qRT-PCR and western blot.

RESULTS

Nineteen TTR substitutions were recombinantly expressed in soluble form, results indicated that reducing the binding energy stabilized the TTR-hnRNPA2B1, while increasing the binding energy had the opposite effect. The native TTR significantly prohibited the proliferation, DNA synthesis, migration and tube formation capacities of hRECs, while fragment 1 always reduced these effects. However, the I68R and D99R substitutions in fragments 2 and 3, respectively, increased the inhibitory effect of TTR. Furthermore, our qRT-PCR and western blot results showed that the expression and protein levels of STAT-4, miR-223-3p and FBXW7 were also regulated by the alteration of the TTR-hnRNPA2B1 interface.

CONCLUSION

This work suggests that the formation of the TTR-hnRNPA2B1 complex plays vital role in hyperglycemia, and modification of this interface regulates the TTR-mediated inhibition of hREC neovascularization via the STAT-4/miR-223-3p/FBXW7 pathway. This mechanism could have important implications for diabetic retinopathy treatment.

Dealing with rhegmatogenous retinal detachment in patients under 40 years old: a tertiary center results

PURPOSE

The risk of rhegmatogenous retinal detachment (RRD) increases with age, but some studies report a secondary peak in younger patients. Since visual recovery in RRD depends on surgical treatment and, considering the personal, social and economic burden of low vision in the working-age population, our purpose was to analyze the features and outcomes of RRD in young patients.

METHODS

Clinical data of patients under 40 years old submitted to surgery for first time RRD, consecutively selected between 2016 and 2019, was analyzed. Patients with less than 3 months follow-up were excluded.

RESULTS

Eighty-nine eyes from 89 patients were included. Mean age was 31.2 ± 7.8 years (minimum 10 years) and 56% were female gender. Most patients (63%) had high myopia. Pars plana vitrectomy (79%) alone, combined with scleral buckling (1%) or scleral buckling alone (20%) was performed. Primary anatomical success was 72%, and final anatomical success was 91%. Final visual acuity of 20/40 or better was achieved in 29% of cases, but 28% remained under 20/400. The presence of myopia (p = 0.022), localized RRD (p = 0.007) and attached macula at presentation (p < 0.001) was associated with a better final visual acuity.

CONCLUSION

Management of RRD in young patients must be thorough. In younger patients, anatomical outcomes may be worse than in older patients. Myopia may be recognized as a major risk factor for RRD in this age group, but also as a protective factor for retinal function after surgery.

Transthyretin Upregulates Long Non-Coding RNA MEG3 by Affecting PABPC1 in Diabetic Retinopathy

The aim of the study was to demonstrate how transthyretin (TTR) could affect long non-coding RNA (lncRNA) of maternally expressed gene 3 (MEG3) and play important roles in diabetic retinopathy (DR). A DR model in C57BL/6 mice was established after intraperitoneal injection of streptozotocin (STZ). After intravitreal injection with TTR pAAV vector, MEG3 short hairpin RNA (shRNA), scrambled shRNA, or MEG3, retinal imaging, retinal trypsin digestion, and fundus vascular permeability tests were performed. Cell counting kit-8 (CCK8), transwell, and Matrigel assays were employed to detect the proliferation and migration of human retinal microvascular endothelial cells (hRECs). The binding between long non-coding RNA of maternally expressed gene 3 (lncRNA-MEG3) and microRNA-223-3p (miR-223-3p) was observed by using luciferase reporter assays, while co-immunoprecipitation (co-IP) was employed to confirm the interaction between TTR and the target. In the DR mice model, retinal vascular leakage and angiogenesis were repressed by overexpressing TTR. In vitro, the added TTR promoted the level of lncRNA-MEG3 by interacting with poly (A) binding protein cytoplasmic 1 (PABPC1), and then repressed proliferation and angiogenesis of hRECs. In vivo, silencing or overexpressing lncRNA-MEG3 significantly affected retinal vascular phenotypes. Additionally, the interaction between lncRNA-MEG3 and miR-223-3p was confirmed, and silencing of miR-223-3p revealed similar effects on hRECs as overexpression of lncRNA-MEG3. In summary, in the DR environment, TTR might affect the lncRNA MEG3/miR-223-3p axis by the direct binding with PABPC1, and finally repress retinal vessel proliferation.

Transcriptome analysis identified a novel 3-LncRNA regulatory network of transthyretin attenuating glucose induced hRECs dysfunction in diabetic retinopathy

Background

Diabetic retinopathy (DR) is the leading cause of blindness in the working age population. Transthyretin (TTR) showed a significantly decreased concentration in DR patients and exerted a visual protective effect by repressing neovascularization. This work intended to identify long non coding RNAs (lncRNAs) and explore their potential mechanism underlying the protective role of TTR.

Methods

Transcriptome of human retinal endothelial cells (hRECs) treated with low glucose (LG), high glucose (HG) or high glucose with 4 μM TTR (HG + TTR) was conducted. Differentially expressed lncRNAs, mRNAs and TTR related lncRNAs and mRNA were acquired. Functional annotation and Gene Set Enrichment Analysis were applied to analyse TTR affected pathways and processes. Weighted gene co-expression network analysis (WGCNA) was implemented to obtain hub modules and genes. LncRNA-mRNA regulatory networks were constructed based on cis, trans and competing endogenous RNAs acting mode. QRT-PCR was conducted to validate the expression of lncRNAs in aqueous humor and serum samples from 30 DR patients and 10 normal controls.

Results

RNA-sequencing of hRECs treated with low glucose (LG), high glucose (HG) or high glucose with 4 μM TTR (HG + TTR) was conducted. 146,783 protein-coding transcripts, 12,403 known lncRNA transcripts and 1184 novel non-coding transcripts were characterized. A total of 11,407 differentially expressed mRNAs (DE-mRNAs), 679 differentially expressed lncRNAs (DE-lncRNAs) in HG group versus LG group, 6206 DE-mRNAs and 194 DE-lncRNAs in HG + TTR versus HG group were obtained, respectively. 853 TTR-mRNAs and 48 TTR-lncRNAs were acquired, and functionally involved in cell cycle, apoptosis, inflammation signalling pathway, response to oxidative stress, neovascularization and autophagy. The WGCNA analysis identified a hub module of 133 genes, with the core function of oxidative stress response, angiogenesis, MAPK pathway, cell proliferation and apoptosis. After qRT-PCR validation, a 3-lncRNA regulatory network was proposed. At last, lncRNAs MSTRG.15047.3 and AC008403.3 showed significantly relative higher expression levels in both aqueous humor and serum samples, compared with normal controls, and FRMD6-AS2 was significantly down-regulated.

Conclusions

TTR regulated mRNAs and biological processes including oxidative stress, inflammation signalling and autophagy. A 3-lncRNA regulatory network was characterized underlying TTR repressing neovascularization, and showed potential diagnostic performance in DR.