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.