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.
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.
Atrophic age-related macular degeneration (AMD) does not show obvious loss of visual function in the early stage, so it is not easy to be taken seriously. In the advanced stage, most of the patients suffered from macular area retinal map atrophy, which affected night vision and central vision. Drugs currently used in clinical or clinical trials to treat atrophic AMD include drugs for improving choroidal perfusion, reducing the accumulation of harmful substances, preventing oxidative stress injury, inhibiting inflammatory reactions, as well as neuroprotectants and lipid metabolism drugs. Stem cell transplantation for atrophic AMD is currently the most promising treatment. In theory, it is feasible to replace atrophic AMD with retinal photoreceptor cells and RPE cells derived from human stem cell differentiation. However, there are still many problems to be solved, such as how to improve the efficiency of directional differentiation of seed cells and how to ensure the safe and effective RPE cell transplantation and survival after transplantation. At present, several studies have found that multiple locus mutations are associated with atrophic AMD, so gene therapy also plays an important role in the development of the disease.
Age-related macular degeneration (AMD) is an age-related neurodegenerative eye disease characterized by degeneration and progressive death of retinal pigment epithelium (RPE) and photoreceptor cells. In recent years, as a new treatment for AMD, stem cell therapy has attracted wide attention in the field of AMD, and has become a current research hotspot. Although stem cell therapy carries risks such as increased incidence of cancer and immune rejection, it significantly promotes damaged photoreceptor cells and retinal cells by differentiating into RPE cells and other retinal cell types, as well as secreting neurotrophic factors and extracellular vesicles. In particular, the development of embryonic stem cell-derived RPE cells, its cryopreservation technology and the advancement of plasmid, adeno-associated virus, Sendai virus and other delivery technologies have laid a solid foundation for stem cell therapy of AMD. As a new method to prevent retinal damage and photoreceptor degeneration, stem cell neuroprotective therapy has shown great potential, and with the continuous maturity and improvement of these technologies, stem cell therapy is expected to provide new ideas for the prevention and treatment of AMD in the future.
Age-related macular degeneration (AMD) is one of the leading irreversible causes of blindness in China. The pathogenesis of AMD is not fully understood at present. Under various stress conditions, cellular senescence is activated, characterized by telomere shortening, mitochondrial dysfunction, DNA damage, and the release of various senescence-related secretory phenotype factors. Senescence is implicated in the pathogenesis of AMD through multiple pathways, contributing to chronic inflammation and the onset and progression of AMD. Mechanisms such as oxidative stress, lipofuscin, β amyloid protein and the membrane attack complex have become hotspots of study in the pathogenesis of AMD. The cyclic guanosine phosphate - adenosine synthase - interferon stimulating factor synthase-stimulator of interferon gene pathway has emerged as a critical signaling pathway in the early development of AMD, providing direction for further research on AMD. Currently, senolytics, selective agents targeting the induction of senescent cell apoptosis, show significant potential in the treatment of AMD. The integration of new technologies with cellular senescence may offer a novel approach to AMD treatment, and intervening in the AMD treatment through anti-cellular senescence pathways holds promising prospects.
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.
