Extrachromosomal circular DNA (eccDNA) is a special class of circular DNA in eukaryotes. Recent studies have suggested that eccDNA is the product of genomic instability and has important biological functions to regulate many downstream biological processes. While NGS (Next-Generation Sequencing)-based eccDNA sequencing has led to the identification of many eccDNAs in both healthy and diseased tissues, the specific biological functions of individual eccDNAs have yet to be clearly elucidated. Synthesizing eccDNAs longer than 1 kb with specific sequences remains a major challenge in the field, which has hindered our ability to fully understand their functions. Current methods for synthesizing eccDNAs primarily rely on chemical oligo synthesis, ligation, or the use of a specific gene editing and recombination systems. Therefore, these methods are often limited by the length of eccDNAs and are complex, expensive, as well as time-consuming. In this study, we introduce a novel method named QuickLAMA (Ligase-Assisted Minicircle Accumulation) for rapidly synthesizing eccDNAs up to 2.6 kb using a simple PCR and ligation approach. To validate the efficacy of our method, we synthesized three eccDNAs of varying lengths from cancer tissue and PC3 cells and confirmed successful circularization through sequencing and restriction enzyme digestion. Additional analyses have demonstrated that this method is highly efficient, cost-effective, and time-efficient, with good reproducibility. Using the method, a well-trained molecular biologist can synthesize and purify multiple eccDNAs within a single day, and it can be easily standardized and processed in a high-throughput manner, indicating the potential of the method to produce a wide range of desired eccDNAs and promote the translation of eccDNA research into clinical applications.

Background: Pre-operative risk scores are more valuable than post-procedure risk scores because of lacking effective treatment for contrast-induced acute kidney injury (CI-AKI). A number of pre-operative risk scores have been developed, but due to lack of effective external validation, most of them are also difficult to apply accurately in clinical practice. It is necessary to review and validate the published pre-operative risk scores for CI-AKI.Materials and methods: We systematically searched PubMed and EMBASE databases for studies of CI-AKI pre-operative risk scores and assessed their calibration and discriminatory in a cohort of 2669 patients undergoing coronary angiography or percutaneous coronary intervention (PCI) from September 2007 to July 2017. The definitions of CI-AKI may affect the validation results, so three definition were included in this study, CI-AKI broad1 was defined as an increase in serum creatinine (Scr) of 44.2 μmol/L or 25%; CI-AKI broad2, an increase in Scr of 44.2 μmol/L or 50%; and CI-AKI-narrow, an increase in Scr of 44.2 μmol/L. The calibration of the model was assessed with the Hosmer-Lemeshow test and the discriminatory capacity was identified by C-statistic.Results: Of the 8 pre-operative risk scores for CI-AKI identified, 7 were single-center study and only 1 was based on multi-center study. In addition, 7 of the scores were just validated internally and only Chen score was externally validated. In the validation cohort of 2669 patients, the incidence of CI-AKI ranged from 3.0%(Liu) to 16.4%(Chen) for these scores. Furthermore, the incidence of CI-AKI was 6.59% (178) for CI-AKI broad1, 1.44% (39) for CI-AKI broad2, and 0.67% (18) for CI-AKI-narrow. For CI-AKI broads, C-statistics varied from 0.44 to 0.57. For CI-AKI-narrow, the Maioli score had the best discrimination and calibration, what’s more, the C-statistics of Maioli, Chen, Liu and Ghani was ≥0.7.Conclusion: Most pre-operative risk scores were established based on single-center studies and most of them lacked external validation. For CI-AKI broads, the prediction accuracy of all risk scores was low. The Maioli score had the best discrimination and calibration, when using the CI-AKI-narrow definition.

Background: Cisplatin binds to serum albumin in the body at a rate of 90%, and high levels of free cisplatin are a significant cause of its nephrotoxicity. Therefore, hypoalbuminemia theoretically poses a significant risk factor for cisplatin-induced acute kidney injury (CIA) and can be easily corrected. However, existing research results are inconsistent. Our aim is to confirm the association between hypoalbuminemia and CIA through a meta-analysis and a dual-center real-world data study.Methods: First, we used a random-effects meta-analysis to summarize the odds ratio (OR) of the risk relationship between hypoalbuminemia and CIA. Then, we conducted a retrospective analysis of patients using cisplatin from Xiangya Third Hospital of Central South University (2014–2023) and Hunan Cancer Hospital (2019–2023) to analyze the relationship between hypoalbuminemia and CIA.Results: The meta-analysis, which included six studies involving 4,359 cases, showed that hypoalbuminemia is associated with an increased risk of CIA (OR, 2.13; 95% CI, 1.37–3.32). A total of 5,452 and 25,214 patients from Xiangya Third Hospital and Hunan Cancer Hospital, respectively, were included. Both centers found a significant association between hypoalbuminemia and an increased risk of CIA (OR, 2.76; 95% CI, 1.94–3.93; OR, 2.88; 95% CI, 2.17–3.81), and the sensitivity analysis results were consistent.Conclusion: Through meta-analysis and dual-center real-world data studies, we confirmed that hypoalbuminemia is an independent risk factor for CIA. Therefore, it is recommended that patients using cisplatin undergo serum albumin level testing and regular monitoring during treatment. Actively adjusting albumin levels may reduce the risk of CIA.