Age-related macular degeneration (AMD) is a blinding eye disease which incidence gradually increases with age. Inflammation participates in AMD pathogenesis, including choroidal neovascularization and geographic atrophy. It is also a kind of self-protective regulation from injury for the eyes. In this review, we described inflammation in AMD pathogenesis, summarized the roles played by inflammation-related cytokines, including pro-inflammatory and anti-inflammatory cytokines, as well as leukocytes (macrophages, dendritic cells, neutrophils, T lymphocytes and B lymphocytes) in the innate or adaptive immunity in AMD. Possible clinical applications such as potential diagnostic biomarkers and anti-inflammatory therapies were also discussed. This review overviews the inflammation as a target of novel effective therapies in treating AMD.

Mitochondria are essential for cellular function and viability, serving as central hubs of metabolism and signaling. They possess various metabolic and quality control mechanisms crucial for maintaining normal cellular activities. Mitochondrial genetic disorders can arise from a wide range of mutations in either mitochondrial or nuclear DNA, which encode mitochondrial proteins or other contents. These genetic defects can lead to a breakdown of mitochondrial function and metabolism, such as the collapse of oxidative phosphorylation, one of the mitochondria’s most critical functions. Mitochondrial diseases, a common group of genetic disorders, are characterized by significant phenotypic and genetic heterogeneity. Clinical symptoms can manifest in various systems and organs throughout the body, with differing degrees and forms of severity. The complexity of the relationship between mitochondria and mitochondrial diseases results in an inadequate understanding of the genotype-phenotype correlation of these diseases, historically making diagnosis and treatment challenging and often leading to unsatisfactory clinical outcomes. However, recent advancements in research and technology have significantly improved our understanding and management of these conditions. Clinical translations of mitochondria-related therapies are actively progressing. This review focuses on the physiological mechanisms of mitochondria, the pathogenesis of mitochondrial diseases, and potential diagnostic and therapeutic applications. Additionally, this review discusses future perspectives on mitochondrial genetic diseases.

Compared to intravitreal injection, subretinal injection has more direct effects on the targeting cells in the subretinal space, which provides a new therapeutic method for vitreoretinal diseases, especially when gene therapy and/or cell therapy is involved. To date, subretinal delivery has been widely applied by scientists and clinicians as a more precise and efficient route of ocular drug delivery for gene therapies and cell therapies including stem cells in many degenerative vitreoretinal diseases, such as retinitis pigmentosa, age-related macular degeneration, and Leber's congenital amaurosis. However, clinicians should be aware of adverse events and possible complications when performing subretinal delivery. In the present review, the subretinal injection used in vitreoretinal diseases for basic research and clinical trials is summarized and described. Different methods of subretinal delivery, as well as its benefits and challenges, are also briefly introduced.

Purpose.: We determined the profile of genes expressed in fibrovascular membranes (FVMs). Methods.: Six FVMs were surgically removed from patients with proliferative diabetic retinopathy (PDR) during pars plana vitrectomy with membrane peeling. The FVMs were classified into three active FVMs or three inactive FVMs according to the presence or absence of neovascularization (NV) in the membranes. Total RNA was isolated from the six FVMs and also from three normal human retinas. The DNA microarray analysis was performed to compare the genes expressed in the FVMs to those in normal human retinas, and also between active and inactive FVMs. Ingenuity pathway analysis (IPA) was used to determine the key biological networks related to the genes that were significantly altered. Quantitative RT-PCR and immunohistochemistry were performed to validate the microarray analyses. Results.: There were 87 genes expressed at significantly higher levels in FVMs than in normal human retinas. Functional classification of these genes showed that the most clustered genes were those related to extracellular matrix formation. The top biological network generated by the IPA was cellular assembly and organization involving nodes of genes related to extracellular matrix formation. These networks included the collagen family and matricellular proteins, THBS2, POSTN, and TNC. There were 91 genes significantly upregulated in active FVMs, and the most clustered functional category was angiogenesis. In contrast, 89 genes were significantly upregulated in inactive FVMs, and the most clustered functional category was metabolism. The IPA revealed that the top biological network related to the genes that were significantly altered in this comparison was cell-to-cell signaling, and interactions involving the PDGF and TGFβ families. The results of quantitative RT-PCR analyses and immunohistochemistry for several selected molecules were in good agreement with the microarray data. Conclusions.: Our data indicate that extracellular matrix-related molecules such as POSTN, TNC, TGFβ, and angiogenic factors have important roles in promoting the development of FVMs associated with PDR.

Choroidal neovascularization (CNV) is a serious complication of age‑related macular degeneration. The aim of the present study was to investigate the expression and distribution of M1 and M2 macrophages in a laser‑induced CNV adult mouse model. The mRNA expression levels of M1, M2 and pan macrophage markers, and macrophage‑associated angiogenic cytokines, were determined by reverse transcription‑quantitative polymerase chain reaction. Immunofluorescence studies were performed to determine the location of the macrophages. The expression levels of M1 macrophage markers increased to a greater extent compared with M2 markers in the retinal pigment epithelium (RPE)‑choroid complexes following laser photocoagulation. By contrast, the expression levels of M2 macrophage markers increased primarily in the retinas. Immunofluorescence studies revealed that the increased number of cluster of differentiation (CD)206‑positive cells were located primarily in the retina, whereas the CD80‑positive cells were located around the site of CNVs in the RPE‑choroid. In addition, the M1‑associated cytokines increased to a greater extent in the RPE‑choroid complexes, whereas the M2‑associated cytokines were highly expressed in the retinas. These findings indicate that M1 and M2 macrophage numbers increased following CNV; however, the locations were different in this mouse model of laser‑induced CNV. The results of the present study suggest that M1 macrophages have a more direct role in inhibiting the development of CNV.

Purpose: To investigate the roles played by M2 macrophages in a mouse model of oxygen-induced retinopathy (OIR). Methods: Oxygen-induced retinopathy was induced in C57BL/6J mice by exposing postnatal day seven (P7) pups to 75% oxygen and then returning them to room air at P12. Real-time RT-PCR and immunofluorescence staining were used to assess the levels and distributions of different macrophage markers. Bone marrow–derived M1 and M2 macrophages and mannosylated clodronate liposomes (MCLs) were injected into the vitreous on P12 to examine the effects at P17. M2 macrophages were cocultured with human retinal endothelial cells (HRECs) to examine their effects on proliferation and tube formation. Results: The results showed that the M2 macrophages, rather than M1 phenotype, were highly expressed in OIR mice. The number of M2 macrophages had increased significantly at P17, and the increase was closely associated with the presence of neovascular tufts in the OIR retinas. Selective depletion of M2 macrophages suppressed the pathological neovascularization and promoted physiological revascularization. In contrast, intravitreal injection of bone marrow–derived M2 macrophages or the culture supernatants promoted pathological neovascularization and inhibited physiological revascularization. In an in vitro coculture system, M2-polarized macrophages significantly promoted proliferation and tube formation of HRECs. Conclusions: These results indicated that M2 macrophages, rather than M1, play an important role in promoting retinal pathological neovascularization probably by producing secreted factors. Thus, targeting M2 macrophages could be a potential therapeutic option for inhibiting retinal pathological neovascularization.