Impact of aging in bacterial endophthalmitis

Endophthalmitis is a serious complication of cataract surgery, for the aging population, and is associated with irreversible vision loss and its effect in endophthalmitis has not been fully elucidated. This study aimed to understand the pathobiology of bacterial endophthalmitis in association with age in a murine model as well as in patients with bacterial-endophthalmitis. Bacterial endophthalmitis was induced in aged and young (18–24 months and 6–8 weeks old) C57BL/6 mice, by intravitreal injection of <i>Pseudomonas aeruginosa</i>, followed by assessment of disease progression and enucleation at 24 h post-infection. Eyes were subjected to histopathological analysis along with assessment of inflammatory mediator levels by qPCR. Additionally, these cytokines were further validated in 10 patients with bacterial endophthalmitis, by MILLIPLEX assay, and correlated with their age. Both young and old mice were equally susceptible to <i>P. aeruginosa</i> infection, older mice exhibited higher clinical scores along with increased bacterial burden and inflammation, indicating enhanced disease severity. These findings were confirmed in human vitreous. Immune exacerbation was seen in older mice possibly due to inflammaging, during infection. Identification of pathways underlying altered innate immunity in aging eyes could provide new understandings into the pathology of bacterial endophthalmitis in older patients.

眼内炎（Endophthalmitis）是白内障手术的严重并发症，尤其好发于老年人群，其与不可逆视力丧失密切相关，但其在眼内炎发病中的具体作用尚未完全阐明。本研究旨在通过小鼠模型与细菌性眼内炎（bacterial endophthalmitis）患者，解析与年龄相关的细菌性眼内炎的病理生物学机制。本研究通过玻璃体内注射铜绿假单胞菌（Pseudomonas aeruginosa），分别在老年及年轻C57BL/6小鼠（年龄分别为18~24月龄、6~8周龄）中诱导细菌性眼内炎模型，并于感染后24小时评估疾病进展、摘除眼球。对摘除的眼球进行组织病理学分析，并通过实时定量聚合酶链反应（qPCR）检测炎症介质的表达水平。此外，本研究还通过MILLIPLEX检测法，在10例细菌性眼内炎患者的玻璃体样本中验证了上述细胞因子的表达情况，并与患者年龄进行相关性分析。研究结果显示，尽管年轻与老年小鼠对铜绿假单胞菌感染的易感性无显著差异，但老年小鼠的临床评分更高，细菌载量与炎症反应更为显著，提示疾病严重程度更高。这一发现在人类玻璃体样本中得到了验证。感染过程中，老年小鼠出现免疫过度激活，这可能与免疫衰老（inflammaging）相关。阐明衰老眼部先天免疫功能异常的潜在通路，可为老年患者细菌性眼内炎的病理机制提供新的认知。