Protective effects of lipoic acid-niacin dimers against blue light-induced oxidative damage to retinal pigment epithelium cells

AIM: To evaluate the protective effects of lipoic acid-niacin(N2 L) dimers against blue light(BL)-induced oxidative damage to human retinal pigment epithelium(hRPE) cells in vitro.METHODS: h RPE cells were divided into a control group(CG), a BL group, an N2 L plus BL irradiation group, an α-lipoic acid(ALA) plus BL group, an ALA-only group, and an N2 L-only group. hRPE cellular viability was detected by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium(MTT) bromide assays, and apoptosis was evaluated by annexin-V-PE/7-AAD staining followed by flow cytometry. Ultrastructural changes in subcellular organelles were observed by transmission electron microscopy. Reactive oxygen species formation was assayed by flow cytometry. The expression levels of the apoptosis-related proteins BCL-2 associated X protein(BAX), B-cell leukmia/lymphoma 2(BCL-2), and caspase-3 were quantified by Western blot analysis.RESULTS: BL exposure with a light density of 4±0.5 mW/cm2 exceeding 6 h caused hRPE toxicity, whereas treatment with a high dose of N2 L(100 mol/L) or ALA(150 mol/L) maintained cell viability at control levels. BL exposure caused vacuole-like degeneration, mitochondrial swelling, and reduced microvillus formation;however, a high dose of N2 L or ALA maintained the ultrastructure of hRPE cells and their organelles. High doses of N2 L and ALA also protected hRPE cells from BL-induced apoptosis, which was confirmed by Western blot analysis: BCL-2 expression significantly increased, while BAX and caspase-3 expression slightly decreased compared to the CG.CONCLUSION: High-dose N2 L treatment(>100 mol/L) can reduce oxidative damage in degenerating hRPE cells exposed to BL with an efficacy similar to ALA.

One year results of presbyLASIK using hybrid bi-aspheric micro-monovision ablation profile in correction of presbyopia and myopic astigmatism

●AIM:To analyze one year clinical outcomes and subjective rating of hybrid bi-aspheric multifocal central presbyLASIK with micro-monovision for correction of presbyopia and myopic astigmatism.●METHODS:Seventy-four eyes of 37 patients consecutively treated with presbyLASIK were assessed.The mean age of the patients was 43.8±3.0 y with a mean spherical equivalent refraction of-5.21±1.87 diopters(D)and mean astigmatism of-0.82±0.64 D.Visual acuity,manifest refraction,contrast sensitivity,aberrometry and patients’subjective rating were evaluated pre-and postoperatively.●RESULTS:At 1 y postoperatively(68 eyes of 34 patients),the mean spherical equivalent(SE)refraction in distance eyes was 0.06±0.05 D,whereas the achieved SE in near eyes was-0.83±0.05 D.Ninety-nine percent of eyes were within±0.50 D of target correction of SE.The binocular mean uncorrected distance visual acuity(UDVA)was 0.00±0.18 logMAR(20/20).Sixty-four percent of patients achieved 0.0 logMAR(20/20)or better of UDVA and 0.1 logRAD or better of UNVA as well.There was a binocularly loss of one line CDVA after surgery for only one patient(3%,1/34)and no patient lost 2 lines.The changes in binocular contrast sensitivity(CS)in all test conditions were not significant at any frequency after surgery.The changes of entire eye total higher order aberrations(tHOA)and spherical aberrations(SA)significantly higher in near eyes than in distance eyes.The overall satisfaction score for surgery was 93±8.●CONCLUSION:The hybrid bi-aspheric multifocal central presby LASIK with micro-monovision appears to be an efficacious option for myopic presbyopes.One year postoperative outcomes in a relatively young presbyopia population indicate improvements in both far and near vision with high satisfaction.

An Association between Corneal Inflammation and Corneal Lymphangiogenesis after Keratoplasty

Purpose:.To examine the relationship between corneal inflammation and corneal lymphangiogenesis after keratoplasty.Methods:.Rat corneal lymphangiogenesis was examined by lymphatic vessel endothelial receptor(LYVE-1) immunohistochemistry and whole mount immunofluorescence at 1, 3, 7,10, and 14 days after corneal transplantation. Corneal inflammation was evaluated by inflammation index(IF) grading and NF-κB immunohistochemistry at the same time points. The association between lymphatic vessel counting(LVC) and the IF scores was then examined.Results:.LYVE-1 positive lymphatic vessels occurred in the corneal stroma on day 3,.developed throughout days 7 and10,.and peaked in number at day 14 after keratoplasty.Corneal inflammation was strong on day 3, and then resolved gradually,.but increased again from days 7 to 14 after the transplantation..LVC was strongly and positively correlated with IF after keratoplasty(r=0.41;P<0.05). However, changes in IF scores and LVC were not parallel.Conclusion:.A close,.but not parallel,.relationship was found between corneal lymphangiogenesis and corneal inflammation after corneal transplantation.

Combine deep lamellar endothelial keratoplasty and anterior lamellar keratoplasty with limbal allograft for severe corneal injury:a case report

Dear Editor,I am Dr.Yi Liu from Department of Ophthalmology,Nanjing Hospital of Chinese Medicine Affiliated to Nanjing University of Chinese Medicine,Nanjing,China.I write to present a case of severe corneal acid-burn injury and describe a novel surgery namely,deep lamellar endothelial keratoplasty(DLEK)and anterior lamellar keratoplasty(ALK)with limbal allograft(LA).

Changes of nitric oxide synthase and cyclic guanosine mono-phosphate in form deprivation myopia in guinea pigs

Background The form deprivation （FD） reduces spatial contrasts and induces myopia. Nitric oxide and cyclic guanosine monophosphate （cGMP） are involved in visual signal transmission. This study investigated changes in nitric oxide synthase （NOS） activity and cGMP concentration in ocular tissues in acute and chronic form deprivation myopia. Methods Guinea pigs had one eye covered by translucent glass for 7, 14 or 21 days. Untreated litter mates were used as controls. NOS activity and cGMP concentrations in the retinal, choroidal and scleral tissues of FD eyes and control eyes were analyzed by radioimmunoassay after various durations of FD. The expression of NOS subtypes was identified by immunohistochemistry. Results Myopia was successfully induced in FD eyes after 14 days. Compared with control groups, the retinal NOS activity and cGMP concentrations in the FD eyes significantly increased after 14 and 21 days while the retinal NOS activity in the FD eyes was transiently suppressed by 7 days of FD. The NOS activity and cGMP concentrations of choroid and sclera in the FD eyes were higher than in the control groups at 21 days. The three isoenzymes of nitric oxide synthase were detected in the ocular tissues of guinea pigs. Conclusions The NOS activity and cGMP concentrations were upregulated after chronic FD and the retinal NOS activity was transiently suppressed at acute FD. The function of elevated NOS activity may be mediated by cGMP.

Role of T-cell receptor V beta 8.3 peptide vaccine in the prevention of experimental autoimmune uveoretinitis

Background T-cell receptor （TCR） plays an important role in the development of autoimmune diseases. Recently, it was reported that immunization of animals with TCR peptide derived from the pathogenic cells could prevent autoimmune diseases. The aim of this study was to investigate whether vaccination with a synthetic peptide from the hypervariable region of TCR Vβ 8.3, an experimental autoimmune uveoretinitis （EAU）-associated gene, was able to prevent the disease. Methods EAU was induced in Lewis rats by immunization with IRBP R16 peptide emulsified in complete Freund＇s adjuvant （CFA）. The clinical and histological appearances were scored. Delayed type hypersensitivity （DTH） and lymphocyte proliferation were detected. Cytokine levels of aqueous humour, supernatants of cells from spleen and draining lymph nodes were measured by enzyme linked immunosorbent assay （ELISA）. Gene expression of TCR Vβ8.3 on CD4^＋ T cells was examined by real time quantitative polymerase chain reaction （PCR）. Results After vaccination, the intraocular inflammation was significantly mitigated, antigen specific DTH and lymphocyte proliferation responses were suppressed, interleukin （IL）-2 in aqueous humour, interferon （IFN）-γ and IL-2 produced by the spleen and draining lymph node cells were significantly decreased, whereas the production of IL-4 and IL-10 were increased. The response of draining lymph node cells to TCR Vβ 8.3 peptide was enhanced after vaccination. Inoculation with CFA alone did not affect the severity of EAU and the above parameters. The suppression of EAU was much stronger in the group of four fold inoculations than the group of two fold inoculations. The expression of TCR Vβ 8.3 gene was significantly reduced in the group of fourfold inoculations. Conclusion Vaccination with the synthetic TCR Vβ 8.3 peptide could remarkably inhibit the development of EAU.

The critical need to establish standards for data quality in intelligent medicine

Medical artificial intelligence(AI)is an important technical asset to support medical supply-side reforms and national development in the big data era.Clinical data from multiple disciplines represent building blocks for the development and application of AI-aided diagnostic and treatment systems based on medical big data.However,the inconsistent quality of these data resources in AI research leads to waste and inefficiencies.Therefore,it is crucial that the field formulatesthe requirements and content related to data processing as part of the development of intelligent medicine.To promote medical AI research worldwide,the“Belt and Road”International Ophthalmic Artificial Intelligence Research and Development Alliance will establish a series of expert recommendations for data quality in intelligent medicine.

Applications and potentials of nanopore sequencing in the(epi)genome and(epi)transcriptome era

The Human Genome Project opened an era of(epi)genomic research,and also provided a platform for the development of new sequencing technologies.During and after the project,several sequencing technologies continue to dominate nucleic acid sequencing markets.Currently,Illumina(short-read),PacBio(long-read),and Oxford Nanopore(longread)are the most popular sequencing technologies.Unlike PacBio or the popular short-read sequencers before it,which,as examples of the second or so-called Next-Generation Sequencing platforms,need to synthesize when sequencing,nanopore technology directly sequences native DNA and RNA molecules.Nanopore sequencing,therefore,avoids converting mRNA into cDNA molecules,which not only allows for the sequencing of extremely long native DNA and full-length RNA molecules but also document modifications that have been made to those native DNA or RNA bases.In this review on direct DNA sequencing and direct RNA sequencing using Oxford Nanopore technology,we focus on their development and application achievements,discussing their challenges and future perspective.We also address the problems researchers may encounter applying these approaches in their research topics,and how to resolve them.

Menin expression is regulated by transforming growth factor beta signaling in leukemia cells

Background Menin is a ubiquitously expressed protein encoded by the multiple endocrine neoplasia type 1 （MEN1）gene. Besides its importance in endocrine organs, menin has been shown to interact with the mixed lineage leukemia （MLL） protein, a histone H3 lysine 4 methyltransferase, and plays a critical role in hematopoiesis and leukemogenesis.Previous studies have shown that menin promotes transforming growth factor beta （TGF-β） signaling in endocrine cells.However, little is known regarding the impact of TGF-β pathway on menin in hematopoietic system. Here, with leukemia cell lines generated from conditional MEN1 or TGF-p receptor （TβRII） knockout mouse models, we investigated the possible cross-talk of these two pathways in leukemia cells.Methods MEN1 or TβRII conditional knockout mice were bred and the bone marrow cells were transduced with retroviruses expressing oncogeneic MLL-AF9 （a mixed lineage leukemia fusion protein） to generate two leukemia cell lines. Cell proliferation assays were performed to investigate the effect of TGF-β treatment on MLL-AF9 transformed leukemia cells with/without MEN1 or TβRII excision. Menin protein was detected with Western blotting and mRNA levels of cell proliferation-related genes Cyclin A2 and Cyclin E2 were examined with real-time RT-PCR for each treated sample.In vivo effect of TGF-p signal on menin expression was also investigated in mouse liver tissue after TβRII excision.Results TGF-β not only inhibited the proliferation of wild type MLL-AF9 transformed mouse bone marrow cells, but also up-regulated menin expression in these cells. Moreover, TGF-P failed to further inhibit the proliferation of Men1-null cells as compared to Men1-expressing control cells. Furthermore, excision of TβRII, a vital component in TGF-β signaling pathway, down-regulated menin expression in MLL-AF9 transformed mouse bone marrow cells. In vivo data also confirmed that menin expression was decreased in liver samples of conditional TβRII knockout mice after TβRII excision.Conclusion These results provided the first piece of evidence of cross-talk between menin and TGF-β signaling pathways in regulating proliferation of leukemia cells, suggesting that manipulating the cross-talk of the two pathways may lead to a novel therapy for leukemia.

The inter-visit variability of retinal blood flow velocity measurements using retinal function imager (RFI)

Background:To determine the inter-visit variability of retinal blood flow velocities(BFVs)using a retinal function imager(RFI)in healthy young subjects.Methods:Twenty eyes of 20 healthy young subjects were enrolled.RFI imaging was performed to obtain the BFVs in retinal arterioles and venules in a field measuring 7.3×7.3 mm^(2)(setting:35 degrees)centered on the fovea,and repeated measurements were obtained on two separate days.The inter-visit variability of BFVs was assessed by the concordance correlation coefficient(CCC)and coefficient of variance(CV).Results:At the first visit,the mean BFV was 3.6±0.8 mm/s and 3.0±0.7 mm/s in arterioles and venules,respectively,which were not significantly different from those at the second visit(the BFV of arterioles was 3.5±0.8 mm/s,and the BFV of venules was 3.0±0.7 mm/s,P>0.05,respectively).The CCC was 0.72 in the BFVs of arterioles and 0.67 in venules,and the CV was 10.8%in the BFVs of arterioles and 11.0%in venules.Conclusion:The inter-visit variability using the retinal function imager(RFI)with a large field of view appeared to be good and comparable to previously reported intra-visit and inter-eye variability.