Circulating Small Extracellular Vesicles Involved in Systemic Regulation Respond to RGC Degeneration in Glaucoma.

Glaucoma is a leading cause of irreversible blindness worldwide and is characterized by progressive retinal ganglion cell (RGC) degeneration and vision loss. Since irreversible neurodegeneration occurs before diagnosable, early diagnosis and effective neuroprotection are critical for glaucoma management. Small extracellular vesicles (sEVs) are demonstrated to be potential novel biomarkers and therapeutics for a variety of diseases. In this study, it is found that intravitreal injection of circulating plasma-derived sEVs (PDEV) from glaucoma patients ameliorated retinal degeneration in chronic ocular hypertension (COH) mice. Moreover, it is found that PDEV-miR-29s are significantly upregulated in glaucoma patients and are associated with visual field defects in progressed glaucoma. Subsequently, in vivo and in vitro experiments are conducted to investigate the possible function of miR-29s in RGC pathophysiology. It is showed that the overexpression of miR-29b-3p effectively prevents RGC degeneration in COH mice and promotes the neuronal differentiation of human induced pluripotent stem cells (hiPSCs). Interestingly, engineered sEVs with sufficient miR-29b-3p delivery exhibit more effective RGC protection and neuronal differentiation efficiency. Thus, elevated PDEV-miR-29s may imply systemic regulation to prevent RGC degeneration in glaucoma patients. This study provides new insights into PDEV-based glaucoma diagnosis and therapeutic strategies for neurodegenerative diseases.

A sutureless technique for securing leaking sclerotomies with viscoelastic substances in 23-gauge microincision vitrectomy surgery.

AIM: To introduce and evaluate the clinical efficacy of a new technique, the use of viscoelastic substances (VS) to close leaking sclerotomy in 23G microincision vitrectomy, and to observe its effect on the visual acuity and intraocular pressure (IOP) of patients. METHODS: Patients who underwent 23G vitrectomy in Ningbo Eye Hospital before the use of VS technique (June 2019 to September 2020) and after the use of VS technique (October 2020 to December 2021) were selected as the subjects of this study. The above cases underwent operation by the same surgeon and were retrospectively analyzed. VS technique was used as the alternative to suturing, in which a small amount of VS was injected at the leaking sclerotomy and then gently massaged to confirm leaking sclerotomy closure. RESULTS: A total of 174 eyes were covered in the study, including 84 eyes in the control group (before the use of VS technique) and 90 eyes in the VS technique group. The number of eyes that needed to be sutured decreased considerably from 42.9% in the control group to 3.3% in the VS technique group, and the proportion of subconjunctival hemorrhage at 1-2d after surgery decreased remarkably from 35.7% in the control group to 2.2% in the VS technique group. No substantial differences in the incidence of mean IOP and low IOP were found between 1-2 and 3-20d after surgery in the VS technique group. No major complications associated with VS technique were identified during the study. CONCLUSION: In 23G microincision vitrectomy, VS technique is a safe, simple, and effective method to close leaking sclerotomy.

The melatonin receptor 1B gene links circadian rhythms and type 2 diabetes mellitus: an evolutionary story.

Disturbed circadian rhythms have been a risk factor for type 2 diabetes mellitus (T2DM). Melatonin is the major chronobiotic hormone regulating both circadian rhythm and glucose homeostasis. The rs10830963 (G allele) of the melatonin receptor 1B (MTNR1B) gene has the strongest genetic associations with T2DM according to several genome-wide association studies. The MTNR1B rs10830963 G allele is also associated with disturbed circadian phenotypes and altered melatonin secretion, both factors that can elevate the risk of diabetes. Furthermore, evolutionary studies implied the presence of selection pressure and ethnic diversity in MTNR1B, which was consistent with the "thrifty gene" hypothesis in T2DM. The rs10830963 G risk allele is associated with delayed melatonin secretion onset in dim-light and prolonged duration of peak melatonin. This delayed melatonin secretion may help human ancestors adapt to famine or food shortages during long nights and early mornings and avoid nocturnal hypoglycemia but confers susceptibility to T2DM due to adequate energy intake in modern society. We provide new insight into the role of MTNR1B variants in T2DM via disturbed circadian rhythms from the perspective of the "thrifty gene" hypothesis; these data indicate a novel target for the prevention and treatment of susceptible populations with the thrifty genotype.

Shared and specific biological signalling pathways for diabetic retinopathy, peripheral neuropathy and nephropathy by high-throughput sequencing analysis.

OBJECTIVES: We aimed to explore the shared and specific signalling pathways involved in diabetic retinopathy (DR), diabetic peripheral neuropathy (DPN) and diabetic nephropathy (DN). METHODS: Differentially expressed mRNAs and lncRNAs were identified by high-throughput sequencing. Subsequently, functional enrichment analysis, protein-protein interaction (PPI) analysis and lncRNAs-mRNAs networks were conducted to determine the pathogenic mechanisms underlying DR, DPN and DN. RESULTS: Twenty-six biological pathways were shared among DR, DPN and DN groups compared to the type 2 diabetes mellitus (T2DM) group without complications, and most of the shared pathways and core proteins were involved in immune and inflammatory responses of microvascular damage. Cytokine‒cytokine receptor interactions and chemokine signalling pathway were the most significant and specific pathways for DR, and the lncRNA‒mRNA regulatory networks affected DR by targeting these pathways. Sphingolipid metabolism and neuroactive ligand-receptor pathways were found to be specific for the pathogenesis of DPN. Moreover, multiple amino acid metabolic pathways were involved in the occurrence and progression of DN. CONCLUSIONS: Diabetic retinopathy, DPN and DN exhibited commonality and heterogeneity simultaneously. The shared pathologic mechanisms underlying these diabetic complications are involved in diabetic microvascular damage via immune and inflammatory pathways. Our findings predict several biomarkers and therapeutic targets for these diabetic complications.

Association of IL-6 Gene (-174 and -572 G/C) Polymorphisms with Proliferative Diabetic Retinopathy of Type 2 Diabetes in a Chinese Population.

PURPOSE: To investigate the association of interleukin (IL)-6 with proliferative diabetic retinopathy (PDR) of type 2 diabetes (T2D) in a Chinese population. METHODS: Two subtypes of the IL-6 promoter (-174 and -572 G/C) were genotyped in 215 T2D patients with PDR and 207 T2D patients with a normal retinal function (controls) using the PCR-RFLP method. The mRNA and protein expression of IL-6 was examined by real-time PCR. RESULTS: T2D patients with PDR had a significantly higher frequency of IL-6 -174 GC (OR 0.58; 95% CI 0.34-0.99; p = 0.011) and IL-6 -572 GG (OR 0.53; 95% CI 0.24-1.14; p = 0.016) than T2D controls. The mRNA expressions of the rs1800795 GC and rs1800796 GG genotype were significantly increased compared to other cases (Fsig = 0.002, p = 0.001, respectively), followed by a relative increase in IL-6 in protein. CONCLUSIONS: IL-6 genotypes of rs1800795 GC and rs1800796 GG might point to a relatively high risk for T2D patients suffering from PDR in a Chinese population and they were associated with elevation of IL-6 expression in both mRNA and protein.

The Association between Smoking and Epiretinal Membrane.

We conducted a meta-analysis of analytic and observational studies to evaluate the association between smoking and epiretinal membrane (ERM). The pertinent studies were identified via a literature search using three databases (MEDLINE, Cochrane Library, Embase) and the reference lists of retrieved studies. Cohort, case-control and cross-sectional studies meeting the predefined criteria were included. We extracted the odds ratios (OR) and 95% confidence intervals (CI) from each study. Overall risk estimates were pooled using random-effects models. Subgroup analyses based on several stratified factors were also performed. Two cohort studies and six cross-sectional studies involving 46,837 subjects were included. The pooled effect of all eight studies showed an unexpected significant decreased association between smoking and the occurrence of ERM (OR, 0.72; 95% CI 0.61-0.84; p = 0.29, I2 = 17.9%). Subgroup analyses supported this finding, except for the age-unadjusted group (OR, 0.87; 95% CI 0.63-1.22), the ERM classification group (cellophane macular reflex (CMR) OR, 0.93; 95% CI 0.68-1.28; preretinal macular fibrosis (PMF) OR, 0.74; 95% CI 0.41-1.32), the Asian group (OR, 0.75; 95% CI 0.52-1.09) and the past smoker group (OR, 1.02; 95% CI 0.85-1.22). The pooled effects from the current literature suggested a declining association between smoking and ERM, which requires further studies to confirm.

Novel CHM mutations identified in Chinese families with Choroideremia.

Choroideremia is a bilateral and progressive X-linked inherited disease characterized by widespread chorioretinal atrophy with relative sparing of the macular region. It is caused by mutations in the ubiquitously expressed CHM gene, which lead to the absence of the Rab escort protein 1 (REP-1), resulting in prenylation deficiency. Typical fundus appearances for choroideremia were found in 3 probands from three unrelated Chinese families in our study. We firstly used the targeted exome sequencing (TES) technology to detect mutations in CHM gene. Based on an established filtering strategy of data analyses, along with confirmation by co-segregation, a previously reported mutation (c.1584_1587del TGTT, p.V529Hfs*7) was identified in one family, while two novel mutations (c.227_232delinsTGTCATTTCA, p.Q76Lfs*7; c.710dupA, p.Y237_S238delinsX) were identified in the other two families. These findings not only expands the currently limited spectrum of Chinese disease-causing variants in CHM gene, but also increases our understanding of the phenotypic and genotypic correlations of choroideremia, and may potentially lead to improved genetic counseling and specific treatment for families with choroideremia as well.

A novel CRX mutation by whole-exome sequencing in an autosomal dominant cone-rod dystrophy pedigree.

AIM: To identify the disease-causing gene mutation in a Chinese pedigree with autosomal dominant cone-rod dystrophy (adCORD). METHODS: A southern Chinese adCORD pedigree including 9 affected individuals was studied. Whole-exome sequencing (WES), coupling the Agilent whole-exome capture system to the Illumina HiSeq 2000 DNA sequencing platform was used to search the specific gene mutation in 3 affected family members and 1 unaffected member. After a suggested variant was found through the data analysis, the putative mutation was validated by Sanger DNA sequencing of samples from all available family members. RESULTS: The results of both WES and Sanger sequencing revealed a novel nonsense mutation c.C766T (p.Q256X) within exon 5 of CRX gene which was pathogenic for adCORD in this family. The mutation could affect photoreceptor-specific gene expression with a dominant-negative effect and resulted in loss of the OTX tail, thus the mutant protein occupies the CRX-binding site in target promoters without establishing an interaction and, consequently, may block transactivation. CONCLUSION: All modes of Mendelian inheritance in CORD have been observed, and genetic heterogeneity is a hallmark of CORD. Therefore, conventional genetic diagnosis of CORD would be time-consuming and labor-intensive. Our study indicated the robustness and cost-effectiveness of WES in the genetic diagnosis of CORD.

Molecular screening of the LPCAT1 gene in patients with retinitis pigmentosa without defined mutations in known retinitis pigmentosa genes.

Retinitis pigmentosa (RP) is an inherited retinopathy, which affects the photoreceptors in the retina. Lysophosphatidylcholine acyltransferase (LPCAT) is a critical phospholipid biosynthesis enzyme, which promotes the conversion of lysophosphatidylcholine into phosphatidylcholine in the remodeling pathway of PC biosynthesis. A previous study reported a homozygous insertion in the LPCAT1 gene in mice exhibiting retinal degeneration (rd11). However, whether genetic mutations in LPCAT1 predispose individuals to RP remains to be elucidated. Therefore, the aim of the present study was to investigate whether LPCAT1 mutations exist in patients with RP. A total of 50 unrelated patients diagnosed with either a sporadic or recessive inheritance pattern of RP were recruited in the present study. All of the patients were comprehensively screened for genes associated with the predisposition of RP, and no pathogenic mutations were identified. Reverse transcription-polymerase chain reaction and Sanger sequencing were performed to investigate the coding regions and exon­intron boundaries of the LPCAT1 gene in the recruited patients. In total, three genetic variations in the coding regions, which lead to amino acid changes, were identified. Although two of these mutations were predicted to be pathogenic, co­segregation analysis in the pedigrees excluded these as disease­causing mutations. In addition, the LPCAT1 gene was screen in a panel of RP patients who exhibited no identifiable mutations in any of the known RP­associated genes. No disease­causing mutations in the LPCAT1 gene were identified, indicating that LPCAT1 either does not confer a genetic predisposition to RP, or that the incidence of mutations in LPCAT1 is particularly rare in patients with RP.

[Clinical application of deep lamellar keratoplasty for corneal macula after viral keratitis].

OBJECTIVE: To explore the clinical safety and efficacy of deep lamellar keratoplasty for corneal macula after viral keratitis. METHODS: A total of 16 patients (16 eyes) of corneal macula after viral keratitis at our center from January 2009 to June 2011 received anti-virus eye-drops and then underwent deep lamellar keratoplasty when inflammation were dissolved or quiescent. And the corneal graft diaphaneity and corneal graft rejection reactions were observed. RESULTS: All 16 patients were recovered with a success rate of 100%. After a follow-up of 18-24 months, all corneal grafts were transparent and best-corrected visual acuity was 0.2-0.6. There was no reoccurrence during the follow-up period. After a follow-up of several months, 2 of them had rejection reaction and were controlled after treatment. No rejection reaction occurred during the long-term follow-up. CONCLUSION: As a safe and efficacious procedure, deep lamellar keratoplasty can significantly raise vision acuity with few complications.

[The visual functional therapeutic effects of deep lamellar keratoplasty and penetrating keratoplasty for fungal corneal ulcer].

OBJECTIVE: To investigate the visual functional therapeutic effects of deep lamellar keratoplasty (DLK) and penetrating keratoplasty (PK) on perforated fungal keratitis. METHODS: 64 patients (64 eyes) of fungal corneal ulcer in Ophthalmology Center of Ningbo Yinzhou People Hospital from 2004 to 2009 were retrospected, of which undergo DLK (36 patients, 36 eyes) and PK (28 patients, 28 eyes), and followed up by 12 to 24 months. Check two sets of patients' VA and refraction before operation, and analyze the best-corrected visual acuity (BCVA), corneal refraction changes, corneal endothelium counting and complications, using χ(2) test and t-test. RESULTS: The BCVA after the operation of two sets are both improved, 32 eyes of DLK set were above 0.4, 19 eyes of PK set were above 0.4, of which the DKL set is a bit better than PK set (χ(2) = 4.304, P > 0.05). The astigmatism of DLK set is smaller than the PK set after operation, and there is significant difference (χ(2) = 4.98, P < 0.05). The astigmatism of two sets on the average were all no more than 5.00 D. The reject reaction of keratoplasty of DLK is less than PK, there is obviously significant difference (χ(2) = 34.17, P < 0.05). CONCLUSIONS: There is less complications of DLK than PK for fungal corneal ulcer. DLK can reduce the occurrence of reject reaction of endothelium type, and the BCVA, refraction of DLK after operation is similar to PK, the incidence rate of surgical operation failure is low.

Morphological characteristics of the anterior ethmoidal artery in ethmoid roof and endoscopic localization.

OBJECTIVES: To provide anatomical data to help identify and locate the anterior ethmoidal artery (AEA) precisely during endoscopic procedures. METHOD: We dissected 15 adult cadaver heads, which provided 30 specimens, to study morphological characteristics, courses, and several types of variations. RESULTS: We found the average diameter of the AEA to be 0.80 +/- 0.24 mm. In 85.7% of the cases, the artery was seen between the second and third lamella. Other locations were over the roof of the frontal recess cells (10.7%) and the roof of the posterior ethmoid sinus (3.6%). The AEA ran parallel to the ethmoid roof and formed a slight curve. When viewed from the superior side, the angle formed by the long axis of the artery and the lamina papyracea was 60.5 degrees +/- 16.4 degrees. In 83.3% of the cases, the anterior ethmoidal canal (AEC) was identified as a separate canal, and in 16.7% the canal was embedded in the ethmoid roof. In 10 of the 30 cases (33.3%), the AEC presented some degree of dehiscence. CONCLUSION: As a result of these dissections, we found that the AEA's course in the ethmoid roof varies. The morphological characteristics-that the AEA runs parallel to the ethmoid roof, forming a slight posterolateral to anteromedial curve as it passes from the orbit to the cribriform plate-are the most reliable factors used to identify the artery during surgery.