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.
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 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 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.
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 investigate the polymorphism of the vitamin D receptor gene (VDR)TaqⅠin relation to diabetic retinopathy. Method Fragment length discrepant allele specific PCR(FLDAS-PCR) were used to determine VDR genetypes in 158 patients with diabetic retinopathy and in 198 normal subjects. Results The frequency distribution of VDR genotypes in diabetic retinopathy patients was 106 (67.1%) in TT, 33(20.9%) in Tt, 19(12.0%) in tt; and in normal persons was 165 (83.3%) in TT, 23(11.6%) in Tt, 10 (5.1%) in tt. There was a significant difference between diabetic retinopathy patients and normal persons in distribution of VDR gene TaqⅠgenotypes(Plt;0.05). Conclusions There is some distribution alterations of VDR gene polymorphism in diabetic retinopathy patients. (Chin J Ocul Fundus Dis, 2006, 22: 94-96)
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)
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)
PURPOSE:To investigate the status and detailed structure of Rb gene in primary tumors and somatic cells of patients with retinoblastoma. To identify the character, origin and transmission of oncogenie point mutations. METHODS:DNA hybridization,SSCP analysis and PCR-associated direct sequencing. RESULTS:Among 108 RB patients examined 80 cases were found to have subtle alterations affecting Rb locus,including 44 cases with homozygous Rb point mutations, 20 cases with two independent heterozygous Rb point mutations, 16 cases with heterozygous mutations involved in one allele of Rb gene. Majority of bilateral RB patients and a small fraction of unilateral RB patients were detected to have a germline mutation. In addition the higher frequency of new germline mutation and parental origin of mutation were observed. CONCLUSION :Rb gene is closely associated with retinoblastoma. Two mutation events and resulting inaetivations of both Rb alleles are required for RB tumorigenesis. Based on our own data,the first event is exclusively point mutation. As for the second event,LOH accounts for two third of cases,point mutation for one third of cases. （Chin J Ocul Fundus Dis,1997,13: 12- 16）
OBJECTIVE:The hereditary form of retinoblastoma(RB)is a monogenic disorder which is due to germinal mutation of RB susceptibility gene located on 13q14.The majority of hereditary RB cases transmit as a Mendelian autosomal dominant inheritance that 50% of the offspring of a carrier will inherit the disorder susceptibility gene and all carriers will develop the disorder.The authors report 3 hereditary RB families with incompleted penetrance and irregular transmission of RB phenotype. METHOD:RFLPsamp;VNTRs for analysis of haplotype and SSCPamp;direct DNA sequencing for determination of RB point mutation. RESULTS:The mosaicism of Rb gene point mutation resulted in the incompleted penetrance and irregular transmission of RB phentype. CONCLUSION:DAN-based diagnosis can be used to differentiate the hereditary and nonhereditary forms of retinblastoma but only is the direct detection of disease-causing mutation reliable for determnation of carrier and estimation of th e risk for retinoblastoma. （Chin J Ocul Fundus Dis,1996,12: 37- 40）