Epigenetic modifications such as DNA methylation, histone post-translational modifications, non-coding RNA are reversible, heritable alterations which are induced by environmental stimuli. Major risk factors of diabetes and diabetic complications including hyperglycemia, oxidative stress and advanced glycation end products, can lead to abnormal epigenetic modifications in retinal vascular endothelial cells and retinal pigment epithelium cells. Epigenetic mechanisms are involved in the pathogenesis of macular edema and neovascularization of diabetic retinopathy (DR), as well as diabetic metabolic memory. The heritable nature of epigenetic marks also playsakey role in familial diabetes mellitus. Further elucidation of epigenetic mechanisms in DR can open the way for the discovery of novel therapeutic targets to prevent DR progression.
Epigenetics refers to the changes in gene expression level and function caused by non-genetic sequence changes. It can provide the time, location and mode of the genetic information for the execution of DNA sequences, including DNA methylation, histone modification, non-coding RNA and chromatin remodeling. Studies had shown that epigenetics plays an important role in the development of diabetic retinopathy (DR), and it had been found that epigenetic-related treatment regimens had a certain effect on the treatment of DR through animal experiments and in vitro experiments. It was benefit to regulate the development of diabetes and its complications by depth study of DNA methylation, histone modification, miRNA and metabolic memory. An understanding of changes in gene transcriptional mechanisms at the epigenetic level could help us to further study the prevention and control of diabetes and its complications, and to provide new ideas for treatment.
Objective To analyze the relationship of human leukocyte antigen alleles (HLA-A/B, HLA-DRB/DQB) polymorphism and Eales disease, tuberculosis infection in a Han population in Zunyi city of China. Methods The subjects were analyzed by case control study, which consisted of three groups including Eales disease group (47 patients), pulmonary tuberculosis group (36 patients) and normal control group (100 healthy people). Thirty-nine patients in Eales disease group who had complete history were divided into 4 subgroups according to the history and tuberculin PPD test. Twelve patients with past or present pulmonary tuberculosis were in group A, 27 patients without pulmonary tuberculosis were in group B, 27 patients with positive PPD test were in group C, and 12 patients with negative PPD test were in group D. Fifty-nine alleles of HLA-A/B and HLA-DRB/DQB were analyzed by polymerase chain reaction with sequencespecific primers (PCR-SSP) in all subjects. Odds ratios between each group (OR) and 95% confidence interval (CI) were calculated; Frequency distribution of HLA-A02 gene were analyzed for the group A and the TB group. Results The frequency distribution of HLA-A02 （OR=9.719, OR95% CI:4.377-21.580,P=0.000）and HLA-B07 （OR=11.605, OR95% CI:2.397-56.191,P=0.001）alleles in Eales disease group were obviously higher than that in normal control group, but frequency distribution of HLA-A11（OR=0.495, OR95% CI:0.245-1.000,P=0.048）in Eales disease group was obviously lower than that in normal control group. There was no significant difference in frequency distribution of HLA-A02, HLA-A11 and HLA-B07 alleles between groups A and B, and between groups C and D (P＞0.05). The distribution frequency of HLA-A02, HLA-A24, HLA-B07 and HLA-DRB16 alleles among Eales disease group, pulmonary tuberculosis group and control group was statistically different (P＜0.05). The frequency distribution of HLA-A24 alleles in pulmonary tuberculosis group was lower than that in Eales disease group （chi;2=7.289,P=0.007）, but the frequency distribution of HLA-A02 alleles had no significant difference (OR=0.515,P=0.202) between two groups. Conclusions The alleles of HLA-A02 and HLA-B07 may be genetic predisposing genes of Eales disease, but HLA-A11 alleles may be protective gene in population of Han nationality from Zunyi city. The alleles of HLA-DRB16 and HLA-A02 may be genetic predisposing genes of pulmonay tuberculosis. The alleles of HLA-A02 may be a common susceptible gene for Eales disease and pulmonary tuberculosis. HLA-A11 and HLA-A24 alleles were protective genes of Eales disease and pulmonary tuberculosis respectively.
Objective To analyze the new primary mutation in Chinese people with Leberprime;s hereditary optic neuropathy (LHON). Methods Genomic DNA was collected from 260 suspected LHON patients and 100 normal healthy persons. The mitochondria DNA mutation at nucleotide position (NP) 15257 and the hot spot (14452-14601 bp) of ND6 gene which include the mutations at NP (14482, 14498, 14568, 14596, 14495, and 14459) were screened by using polymerase chain reaction (PCR), heteroduplex-single strand conformation polymorphism (HA-SSCP) and restriction fragment length polymorphism (RFLP) analysis and sequencing. Primary mutation spectrum of Chinese race was analyzed. Results Eight kinds of polymorphism of mitochondria DNA were found in 260 suspected LHON patients and 100 normal healthy persons, including NP 14488C, 14518G, and 14617G which hadnrsquo;t been reported (http://www.mitomap.org/). No mutation at NP 15257, 14482, 14498, 14568, 14596, 14495, and 14459 was found. Conclusion The NP 15257A may not be the primary mutation in Chinese. Because of the race difference, 14452-14601 bp in ND6 gene may not be the hot spot in Chinese patients with LHON, and other hot spots may exist. (Chin J Ocul Fundus Dis, 2006, 22: 82-85)
ObjectiveTo observe and analyze the genotype and clinical phenotype in 34 families of familial exudative vitreoretinopathy associated with (FEVR) gene variation.MethodsCohort study. Thirty-four FEVR families, in which the patients and both of their parents were all found to have FEVR-related gene mutations (proband 34 cases, 67 eyes; parents 68 cases, 136 eyes), were included in the study. These patients were identifIed from 722 FEVR patients through genetic screening, which diagnosed in Department of Ophtalmology of Xinhua Hospital and Tianjin Medical University Eye Hospital from January 2010 to December 2018. The probands and their parents underwent a comprehensive ophthalmological examination appropriate to their age, including BCVA, intraocular pressure, axial length, slit lamp examination, indirect ophthalmoscopy, FFA or color fundus photography or wide field color fundus photography. According to the severity of the disease, the clinical manifestations were divided into severe phenotype and mild phenotype. Thirty-four normal healthy people over 40 years old were included as the control group. The peripheral blood samples of FEVR family members and control group members were collected, and the genes known to be involved in FEVR, such as FZD4, LRP5, NDP, TSPAN12, ZNF408 and KIF11, were analyzed by next generation sequencing molecular genetics. The data were statistically analyzed by SPSS. The counting data was expressed in numbers or rates, and tested by Kruskal-Wallis test and χ2 test to find out the existence of significant difference.ResultsIn 67 eyes of the 34 probands, 48 eyes (71.64%) were classified into severe phenotype and 19 eyes (28.36%) were mild phenotype. In 136 eyes of 68 parents of the proband patients, 76 eyes (55.88%) were normal, 60 eyes (44.12%) were classified into mild phenotype, and no severe phenotype was found. A total of 65 variants of FEVR-related genes were detected in the 34 probands, of which LRP5 mutation was the most common (64.61%), followed by FZD4 (12.31%), NDP (10.77%), TSPAN12 (6.15%), ZNF408 (4.62%) and KIF11 (1.54%). Missense mutations were the most common variant in FEVR-related genes. However, the results of correlation analysis indicated that there was no significant correlation between the type of mutation and the severity of clinical phenotype (H=1.775, P=0.620). Among the 65 mutation types, 21 types have been previously identified and 44 were novel in this study. Thirty-nine eyes of 20 cases had only one single pathogenic mutation gene but with multiple mutation sites, 26 eyes of 13 cases carried 2 relevant pathogenic mutation genes, and 2 eyes in one case had 3 pathogenic mutation genes. The mutation frequencies of LRP5, NDP, ZNF408, FZD4, TSPAN12 and KIF11 genes in probands were significantly higher than those in control group, and the difference was statistically significant. The total mutation frequencies of LRP5, NDP, ZNF408, FZD4, TSPAN12 and KIF11 genes in proband group were significantly higher than those in control group (χ2=64.702, P＜0.001).ConclusionsIn the FEVR families, the most frequent mutations were those in LRP5, followed by FZD4, NDP, TSPAN12,ZNF408 and KIF11. Missense mutation is the most common type of FEVR-related gene mutation, but there is no significant correlation between the clinical phenotype and gene variation type. Most of the probands were with severe clinical phenotype, while most of the parents with FEVR pathogenic gene mutation showed normal or mild manifestations.
Objective To investigate the relationship between diabetic retinopathy (DR) and insertion/deletion (a/b) polymorphism of a 27 base pair variable number tandem repeat (VNTR) in intron 4 of the endothelial nitric oxide synthase (eNOS) gene. Methods 321 patients of type 2 diabetes mellitus with over 10 years duration (case group) and 146 normal subjects (control group) were enrolled in this study. All the clients are Han Chinese. The case group was divided into DR subgroup (154 patients) and non-DR (NDR) subgroup (167 patients) according to the results of indirect ophthalmoscope and fundus fluorescent angiography. The VNTR polymorphism in eNOS gene was determined by polymerase chain reaction (PCR) combined with 8% agarose gel electrophoresis. Then the b, a allele frequency and b/b, a/a, b/a allele frequency of two groups were compared, and its correlation with diseases were analyzed. Results The b allele frequency of the VNTR in intron 4 of eNOS gene in the DR group was significantly higher than that in the NDR group（chi;2=4.745，P=0.029；OR=1.685，95%CI=1.050-3.905）and control group（chi;2=6.958，P=0.008；OR=1.891，95%CI=1.172-4.437）; b/b allele frequency in the DR group was also significantly higher than that in the NDR group（chi;2=4.811，P=0.028；OR=1.790，95%CI=1.060-4.645）and control group（chi;2= 5.203，P=0.023；OR=1.859，95%CI=1.087-4.952）. Conclusions The b allele and b/b genotype in intron 4 of eNOS gene in the Han Chinese are closely related to DR.
Objective To investigate the disease-causing gene of Stargardt disease. Method Fifteen patients with Stargardt disease were analyzed with 11 primers of the 11 exons of ABCR gene by using PCR-SSCP and DNA direct sequencing techniques. Results Three newly detected disease-causing mutations were found. Among those mutations, one is a frameshift mutation and others are single base transition. Conclusion This research confirmed that ABCR gene is associated with Stargardt disease, and 3 new mutations of ABCR gene were found. (Chin J Ocul Fundus Dis,2000,16:240-243)
Nanophthalmos is a congenital disorder, which is characterized by small eye without any ocular or systemic malformation. It has autosomal-dominant and recessive forms of inheritance. It manifests as reduced total axial length, high hyperopia and thickened sclera. Nanophthalmos is relatively rare, but at high risk of secondary angle-closure glaucoma, uveal effusion syndrome. It can be spontaneous remission or recurrent, and responses poorly to medication. The effect of systemic glucocorticoid treatment is not ideal. The surgery challenges with very high rate of intra- and post-operative complications such as hemorrhage, choroidal and retinal detachment, malignum glaucoma and uveal effusion, so that the prognosis is poor. It is of great instructive significance to further understand the clinical features, complications and treatment progress and to avoid the missed diagnosis and misdiagnosisi of its complications, and thus choose the right management.
Objective To observe the opticin expression in the eyes of nonobese diabetes (NOD) mice and nondiabetic NOD mice.Methods Twenty NOD mice were divided into diabetic group (experimental group) and nondiabetic group (control group). All the mice were killed by cervical dislocation method.The eyes were harvested, and the vitreous, retina and sclera were separately collected. Western blot and realtime reverse transcriptionpolymerase chain reaction（RT-PCR）were respectively used to determine opticin protein and OPTC mRNA levels.Results The opticin protein level in the vitreous and retina was lower in the experimental group（t=4.42,4.58;P=0.002,0.002）,but is same in thesclera between the 2 groups（t=0.27,P=0.794）.OPTCmRNA level was vitreousgt;retinagt;sclera. OPTCmRNA levels of vitreous and retina in diabetic group were significantly lower（t=3.30,2.48；P=0.01,0.04）; there was no statistical significant on OPTC mRNA of sclera between two groups（t=0.27,P=0.80）.Conclusion Expression of opticin was suppressed in retina and vitreous of diabetic mice.
Objective To observe the relationship between endothelial constitutive nitric oxide synthase (ecNOS) genetic polymorphism and diabetic retinopathy（DR）of non insulindependent diabetes mellitus (NIDDM) patients of the Han nationality.Methods A total of 166 patients who clinical diagnosed with NIDDM as case group, 85 cases of patients (cataract or fracture) and healthy subjects without diabetes, hypertension and kidney disease,over 40 years old of age and without consanguinity between each other were selected as normal control group. Case group were divided into non-DR (NDR) group, nonproliferative-DR (BDR) group and proliferativeDR (PDR) group according to the result of fundus fluorescein angiography. Case group and normal control group subjects all were Han nationality. DNA was extracted from peripheral venous blood; the fourth 27 base pairs (bp) repeat polymorphism of ecNOS gene by was measured by polymerase chain reaction (PCR). Results The 27 bp repeat sequences within the ecNOS gene present in the Han nationality,allele b repeat 5 times, alleles a repeat 4 times. PCR results showed that there are 2 alleles and 3 genotypes in normal control, NDR, BDR and PDR group. The frequency of genotype bb、ab、aa were 80%, 16.5%, 3.5% in normal subjects; 77.2％, 13.9%, 8.9％ in NDR group; 80.5％, 17.1%,2.4％ in BDR group;78.3％, 13%, 8.7％ in PDR group,respectively. The allele frequency (chi;2 =1.841) and gene frequency (chi;2=3.847) were not statistically significant (P＞0.5) in normal control,NDR,BDR and PDR group. Logistic regression analysis showed that there is no relation between DR and ecNOS duplicated gene polymorphism. Conclusions There is 27 bp repeated polymorphism in 4th intron of ecNOS gene, which may not be associated with the DR of NIDDM in the Han nationality.