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.
To perform a meta-analysis of single nucleotide polymorphism needs to calculate gene frequency. This paper employs allele model as an example to introduce how to calculate gene frequency and display the process of a meta-analysis of single nucleotide polymorphism data using Review Manager 5.3 software.
Microparticles are small vesicles that are released by budding of the plasma membrane during cellular activation and apoptotic cell breakdown. A spectrum of cell types can release microparticles including endothelial cells, platelets, macrophages, lymphocytes and tumor cells. Biological effects of microparticles mainly include procoagulant activity, inhibition of inflammation and cancer progression. The present study shows that vitreous microparticles isolated from proliferative diabetic retinopathy (PDR) stimulated endothelial cell proliferation and increased new vessel formation, promoting the pathological neovascularization in PDR patients. Oxidative stress induces the formation of retina pigment epithelium-derived microparticles carrying membrane complement regulatory proteins, which is associated with drusen formation and age related macular degeneration. Microparticles from lymphocyte (LMP) play an important role in anti-angiogenesis by altering the gene expression pattern of angiogenesis-related factors in macrophages. Besides, LMP are important proapoptotic regulators for retinoblastoma cells through reduction of spleen tyrosine kinase expression and upregulation of the p53-p21 pathway which ultimately activates caspase-3. However, how to apply the microparticles in the prevention and treatment of retinal diseases is a major challenge, because the study of the microparticles in the fundus diseases is still limited. Further studies conducted would certainly enhance the application of microparticles in the fundus diseases.
Noninfectious uveitis refers to a category of inflammatory diseases involving the uvea, with the exception of infectious factors or masquerade syndrome. The diagnosis and follow-up of noninfectious uveitis that involving retina or choroid require fundus imaging techniques. Fundus autofluorescence is a noninvasive imaging technique. Compared with fundus colorized photography, fundus fluorescein angiography and indocyanine green angiography, fundus autofluorescence indicates the functional status of retinal pigment epithelium and photoreceptor cells in a better way, thus playing a role in the pathophysiological mechanisms investigating, early diagnosis, disease progression monitoring and prognosis estimating of noninfectious uveitis, such as Vogt-Koyanagi-Harada disease, Behçet disease, multifocal choroiditis, punctate inner choroidopathy, birdshot chorioretinopathy, multiple evanescent white dot syndrome, acute zonal occult outer retinopathy, acute posterior multifocal placoid pigment epitheliopathy and serpiginous choroiditis.
Ras homolog family (Rho)/ Rho-associated coiled-coil kinase (ROCK) signaling pathway widely exists in human and mammal cells, which is closely related to inhibition of repair after optic nerve damage. The expression level of Rho/ROCK signaling pathway-related proteins is up-regulated in glaucoma, and related with the death of retinal ganglionic cell (RGC) and the axon activity. ROCK inhibitors can protect the surviving RGC and promote axon extension with a dose-dependent manner. ROCK inhibitors also can inhibit glial scar formation, lower intraocular pressure and inhibit inflammatory response to some degrees. Rho/ROCK signaling pathway correlates with the optic nerve disease progression, and ROCK inhibitors hope to become a new therapeutic drug.
Serum anti-retinal autoantibodies (ARA) are a group of autoantibodies that bind to retinal auto-antigens with significant biological importance in pathological processes such as retinal degeneration, inflammatory microenvironment formation, and tissue destruction. In recent years, the expression of serum anti-retinal antibodies has been found to be upregulated in patients with various blinding retinal diseases such as age-related macular degeneration, autoimmune retinopathy, and retinitis pigmentosa, closely correlated with the progression of diseases. However, current researches on ARA are incomplete, lacking animal experiments and large randomized controlled clinical trials. As a result, the exact mechanism of ARA is not well understood. Although several studies have demonstrated that serum ARA has an important diagnostic value in hereditary, autoimmune, and degenerative retinal diseases, there still lacks recognized laboratory tests and laboratory indicators with high specificity and sensitivity. Clinical symptoms should be considered when making definitive diagnosis of the diseases. Therefore, clarifying the mechanisms of ARA in retinal dystrophies provides new ideas in early diagnosis and treatments of retinal diseases, which is clinically and scientifically important for the maintenance of visual functions.
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.
Immunogammopathy maculopathy is a newly discovered retinopathy associated with macroglobulinemia in recent years. The main manifestations were retinal vein convulsion and dilation caused by high blood viscosity, retinal interlaminar effusion and macular serous detachment. With the prolongation of the course of disease, the photoreceptor layer and RPE layer in the detachment area showed atrophic changes. The pathogenesis of ophthalmopathy is still unknown. Understanding the clinical features, diagnosis, differential diagnosis and treatment of ophthalmopathy is of great significance for understanding this kind of disease and improving the level of diagnosis and treatment of ophthalmopathy.
Alzheimer's disease is a common neuro-degenerative disease. The clinical diagnosis mainly depends on the patient's complaint, the score of mini-mental state examination and Montreal cognitive assessment scale, and the comprehensive judgment of MRI and other imaging examinations. Retina is homologous to brain tissue, and their vascular systems have similar physiological characteristics to small blood vessels in the brain. Numerous studies found that the thickness of retinal nerve fiber layer, visual function, retinal blood vessels and retinal oxygen saturation were changed in AD patients to different degrees. To explore the formation mechanism and significance of ocular fundus changes in AD patients will be helpful to select specific, sensitive and simple methods for early observation and evaluation of AD.
Corticosteroids, anti-vascular endothelial growth factor, antibiotics and antiviral were the main 4 classes of drugs for intravitreal injection. Depending on the class and volume of medication, age and gender of patients, ocular axial lengths or vitreous humour reflux, intraocular pressure (IOP) can be elevated transiently or persistently after intravitreal injection. Transient IOP elevation occurred in 2 weeks after intravitreal injection, and can be reduced to normal level for most patients. Only a small portion of such patients have very high IOP and need intervention measures such as anterior chamber puncture or lowering intraocular pressure by drugs. Long term IOP elevation is refers to persistent IOP increase after 2 weeks after intravitreal injection, and cause optic nerve irreversible damage and decline in the visual function of patients. Thus drug or surgical intervention need to be considered for those patients with high and long period of elevated IOP. Large-scale multicenter clinical trials need to be performed to evaluate the roles of the drug and patients factors for IOP of post-intravitreal injection, and to determine if it is necessary and how to use methods reducing IOP before intravitreal injection.