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.
The most important difference between systematic review and traditional narrative review lies in their respective quality, namely the degree of bias control. Generally speaking, the sources of bias include the process of literature searching, study selection, data extraction and original studies. A systematic review may greatly reduce bias, as it takes effective steps such as developing search strategies, undertaking funnel plot analysis, using established criteria for study selection, and assessment of the methodology quality of studies. All these help to control, identify and, describe the possible bias.
The pathogenesis of diabetic retinopathy (DR) is complex and there are many related risk factors. It is related to the course of diabetes, blood glucose, blood pressure, and blood lipids, among which the course of disease and hyperglycemia are recognized main risk factors. In addition, other factors which include heredity, gender, age, obesity, pregnancy, insulin use, can also affect the occurrence and development of DR, but there is no unified conclusion about its correlation. A comprehensive understanding of the risk factors that affect DR can provide new ideas for the prevention, diagnosis, treatment, and intervention of DR.
The hallmark lesions of age-related macular degeneration (AMD) are drusen and basal linear deposit which are lipid substances deposited in Bruch membrane or the compartment on the Bruch membrane. There is a prevailing hypothesis that lipid and its oxidized derivant deposited in retina may have important roles in the pathogenesis of AMD. Lipid oxidation products are toxic, may affect the adjacent cells, induce inflammation, and trigger neovascularization.7-ketocholestoral (7KCh), a naturally occurring oxidized form of cholesterol, had been found to be toxic to retinal cells and able to induce chronic inflammation, which may play a critical role in the development of AMD. However the precise mechanism remains to be elucidated. Thus we will make a brief review of 7KCh and its association with AMD.
The fundus lesions caused by high myopia (HM) often lead to irreversible visual impairment or even blindness. However, the pathogenesis of HM and its fundus lesions is still unclear, the intraocular fluid detection technology of micro samples has brought new prospects for the early diagnosis, monitoring and intervention of the fundus lesions. The molecules associated with HM are various and functionally diverse, intermolecular interactions are staggered and the specific mechanism is complex. With the development of intraocular fluid detection technology, while gradually revealing the role of each molecule in the pathogenesis of HM, it is expected to successfully assist clinical work in the future, providing outpost markers for the progress of myopia and targets for early intervention, or providing a new therapy choice for HM fundus lesions at the molecular level targeting pathogenesis, which is expected to provide more accurate and effective treatment for HM patients in the future.
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.
Retinal degeneration mainly include age-related macular degeneration, retinitispigmentosa and Stargardt’s disease. Although its expression is slightly different, its pathogenesis is photoreceptor cells and/or retinal pigment epithelial (RPE) cel1 damage or degeneration. Because of the 1ack of self-repairing and renewal of retinal photoreceptor cells and RPE cells, cell replacement therapy is one of the most effective methods for treating such diseases.The stem cells currently used for the treatment of retinal degeneration include embryonicstem cells (ESC) and various adult stem cells, such as retinal stem cells (RSC), induced pluripotent stem cells (iPSC). and mesenchyma1 stem cells (MSC). Understanding the currentbasic and clinical application progress of ESC, iPSC, RSC, MSC can provide a new idea for the treatment of retinal degeneration.
Acute zonal occult outer retinopathy (AZOOR) is an acquired retinal diseases. The majority of patients who develop AZOOR are women characterized by an acute onset of visual blurred and scotoma with photopsias. The fundus examination is often normal or appeared mild abnormal. The RPE atrophy of fundus is similar with white syndrome. Although FFA and ICGA features are either unremarkable or unrelated to AZOOR, there are still important in differential diagnosis. The characteristic abnormalities appearance of FAF (complicated and varied), OCT (regional anomaly of ellipsoid zone), visual field (visual field defect) and ERG (decreased amplitude and prolonged latency of rod reaction, maximum reaction, cone reaction and scintillation reaction) are considered critical examinations to the diagnosis of AZOOR. Although there is no effective therapy for AZOOR, it has some self-limitation.
The suprachoroidal space is a potential space between the sclera and choroid. Suprachoroidal spacedrug delivery is becoming an applicable method to the ocular posterior segment diseases. Because it targets the choroid, retinal pigment epithelium and retina with high bioavailability and safety, while maintaining low levels elsewhere in the eye. In recent years, new discoveries has been carried out in different areas of interest, such as drug delivery methods, pharmacokinetics and clinical trials. Clinical trials with suprachoroidal space injection of triamcinolone acetonide are executed with promising findings for patients with noninfectious uveitis and diabetic macular edema. Suprachoroidal space triamcinolone acetonide injectable suspension is the first and currently the only agent specifically approved for uveitic macular edema by Food and Drug Administration. Nowadays, many clinical trails with suprachoroidal space drug delivery have been explored, although there are still many risks and uncertainties. With the development of technology in the future, suprachoroidal space drug delivery appears to be a promising treatment modality for ocular posterior segment diseases.