Age-related macular degeneration (AMD) has become one of the leading causes of irreversible blindness worldwide. With the advancement of stem cell technology, tissue engineering and biomaterials, cell-based therapy has been inspiring for many degenerative diseases. For its unique advantages, AMD has become one of the most promising fields for cell-based therapy, which involve retinal pigment epithelium (RPE) cells, induced differentiation of neural retina cells and related cytokine regulations. RPE cells can be derived from human embryonic stem cells (hESC) or Induced pluripotent stem cells (iPS). Recently hESC-derived RPE cells have been applied to patients with dry AMD with initial success in clinical trials. In terms of tissue engineering, studies are focused on factors affecting the long-term survival of transplanted cells, including tissue scaffolds, soluble hybrid materials and scaffold anchoring. This article briefly reviews the RPE differentiation, neural retina differentiation and related cytokines of cell-based therapy and scaffolds, materials, and cell-scaffolds interactions of tissue engineering in AMD treatment.
Objective To investigate the genetic interaction of HLA-DQB1 promoter and coding alleles in the pathogenesis of Vogt-Koyanagi-Harada syndrome (VKH). Methods Eighty-eight Chinese Han patients with VKH and eighty-eight non-VKH normal controls were enrolled in this study. DNA was extracted from white blood cells of the subjects by phenolchloroform method. Thirteen alleles were genotyped by polymerase chain reaction-sequence-specific primers (PCR-SSP), polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and clone-sequencing was applied to determine the polymorphisms of the promoter and coding regions of HLA-DQB1 gene. Chromas and Bioedit software were used to analyze the sequences of the promoter of HLA-DQB1. Chi-square test and Fisher exact test were the statistical methods. Relationships among single nucleotide polymorphism (SNP) in the promoter and coding region were analyzed. Results Twelve of thirteen already known HLA-DQB1 alleles were genotyped by PCR-SSP in VKH patients. The most frequent allele in VKH patients was HLA-DQB10401 (0.318, 56∶176) which was significantly higher in patients than that in normal controls (0.045, 8∶176) (chi;2＝44.00, P＝0.000, OR＝9.8). So was for HLA-DQB10303 (0.068 vs. 0.006, chi;2＝9.67, P＝0.002, OR＝12.81). In contrast, the frequency of HLA-DQB10601 (0.017 vs.0.096, chi;2＝10.39, P＝0.001, OR＝0.16) and HLA-DQB10302 (0.062 vs. 0.193,chi;2＝13.48, P＝0.000, OR＝0.28) in VKH patients were significantly lower than normal controls. Twelve SNP were found in all subjects. The frequency of C allele at position -189C/A in VKH patients was significantly higher than that in controls (0.324 vs. 0.074, chi;2＝45.92, P＝0.000). However, the frequency of G allele at position -227G/A in VKH patients was significantly lower than that in the normal controls (0.011 vs. 0.108, chi;2＝15.63,P＝0.000). The frequency of combination of susceptible alleles in promoter and coding area （-189C and HLA-DQB10401） in VKH patients was statistically higher than that in controls, the frequency of combination of resistant alleles in control (-227G and HLA-DQB10601) was higher than that in VKH patients. Conclusions The specific interactions of SNP in the promoter and coding alleles of HLA-DQB1 are associated with the pathogenesis of VKH.
Objective To analyze the results of diagnostic pars plana vitrectomy (PPV) in patients with uveitis of unknown cause. Methods This is a retrospective case series study. Sixty-five patients (67 eyes) with uveitis of unknown cause were enrolled in this study. There were 31 males (32 eyes) and 34 females (35 eyes). The ages were from 6 to 84 years, with the mean age of (55.00±18.56) years. All eyes were received PPV. Examination of vitreous samples consisted of microbial stains and culture, microbial DNA and antibody detection, cytokine measurement, cytology, flow cytometry and gene rearrangement detection. Results Vitreous analysis was positive in 40 of 67 eyes (59.7%). Positive results indicated bacterial endophthalmitis in 20 of 40 eyes (50.0%), lymphoma in 11 eyes (27.5%), viral IgM and IgG increased significantly in 3 eyes (7.5%), fungal endophthalmitis in 3 eyes (7.5%), IgG of toxocara increased significantly in 2 eyes (5.0%), IgG of toxoplasma Gondii increased significantly in 1 eye (2.5%). Conclusion The diagnostic yield of vitreous samples in uveitis eyes of unknown cause is 59.7%.
ObjectiveTo develop a simple and effective subretinal injection pipeline system to enhance the accuracy and precision of subretinal injection volume control. MethodA retrospective case series study. From May to October 2023, 18 patients (18 eyes) with submacular hemorrhage (SMH) who continuously received modified subretinal injection treatment in Department of Ophthalmology of Peking Union Medical College Hospital were included in the study. Among them, there were 10 males and 8 females. Age were (60.00±7.41) years old. The primary causes included polypoid choroidal vasculopathy (14 cases), retinal macroaneurysm (2 cases), traumatic retinopathy (1 case), and Valsalva retinopathy (1 case). Hemorrhage affected 14 eyes of the fovea centralis. All affected eyes underwent standard three-channel 25G vitrectomy via the flat part of the ciliary body combined with modified subretinal injection of recombinant tissue plasminogen activator. The improved injection system consisted of a 1 ml syringe, a Q-SyteTM connector, a 41G subretinal microinjection needle, a converter and a viscoelastic substance control pipeline. The drug preparation time for subretinal injection (i.e., the time consumed by the system connection step), the injection time, whether bubbles occur during the injection process, and the perioperative complications were recorded and analyzed. ResultThe preparation time prior to drug injection ranged from 231 to 335 seconds, while the injection completion time varied between 45 and 75 seconds. Both times decreased progressively as operator proficiency improved. Among the treated eyes, five received a target injection dose of 0.05 mL and thirteen received 0.10 mL, with all eyes achieving the preset dose accurately. No subretinal bubbles were observed during the injection procedure. Additionally, no intraoperative complications such as retinal hemorrhage or tear secondary to mechanical trauma at the injection site were recorded. Postoperatively, one eye developed anterior chamber hemorrhage, which resolved following intraocular pressure-lowering treatment. No other postoperative complications, including hemorrhage, rhegmatogenous retinal detachment, or infection, were observed in the remaining eyes. ConclusionThe retinal drug injection system developed in this study has a simple structure, safe and stable operation, can achieve precise drug injection, and effectively avoid the formation of bubbles.