Background

Elevated extracellular DNA levels are found in the sputum of patients with cystic fibrosis (CF). However, studies investigating the association of extracellular DNA with CF severity are scarce.

Objective

To evaluate the association of extracellular DNA levels with pulmonary function, antibiotic use, and hospitalization in CF patients.

Methods

This cross-sectional study included CF patients aged ≥5 years who were clinically stable and produced spontaneously expectorated sputum. Extracellular DNA in sputum was quantified, and extracellular DNA networks were seen with immunofluorescence microscopy. Also, cell death profile was assessed. Data on pulmonary function, airway colonization, antibiotic use, and hospitalization in the previous year were collected. Patients were divided into two groups based on median DNA level.

Results

Thirty-three patients were included. Their mean age was 16.3 ± 6.2 years, mean forced expiratory volume in the first second (FEV₁) was 67.0 ± 26.7 (% of the predicted), and mean DNA level was 241.9 ± 147.2 μg/mL. There were significant correlations of DNA level with FEV₁ (r = −0.60; p < 0.001) and forced vital capacity (r = −0.59; p < 0.001). Moreover, patients with higher DNA level (>243.0 μg/mL) had lower FEV₁ (52.1 ± 27.8% vs. 81.1 ± 16.2%; p = 0.001) and required more hospitalizations (68.8% vs. 35.3%; p = 0.05). Additional findings were the presence of extracellular DNA networks and low rates of necrosis and apoptosis.

Conclusion

Elevated extracellular DNA levels in CF sputum are associated with reduced pulmonary function and increased hospitalizations.

中文翻译：

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囊性纤维化患者的痰液中细胞外DNA与肺功能和住院有关。

背景

在患有囊性纤维化（CF）的患者的痰液中发现细胞外DNA水平升高。但是，缺乏研究细胞外DNA与CF严重性之间关系的研究。

目的

为了评估CF患者的细胞外DNA水平与肺功能，抗生素使用和住院的相关性。

方法

这项横断面研究包括≥5岁的CF患者，这些患者临床稳定且产生自发痰痰。定量痰中的细胞外DNA，并用免疫荧光显微镜观察到细胞外DNA网络。此外，评估了细胞死亡情况。收集了前一年的肺功能，气道定植，抗生素使用和住院数据。根据中位DNA水平将患者分为两组。

结果

包括33例患者。他们的平均年龄为16.3±6.2岁，第一秒钟的平均强迫呼气量（FEV ₁）为67.0±26.7（占预测值的百分比），平均DNA水平为241.9±147.2μg/ mL。DNA水平与FEV ₁（r = -0.60; p  <0.001）和强制肺活量（r = -0.59; p  <0.001）显着相关。此外，DNA水平较高（> 243.0μg/ mL）的患者FEV ₁较低（52.1±27.8％vs. 81.1±16.2％; p  = 0.001），并且需要更多的住院治疗（68.8％vs. 35.3％; p = 0.05）。其他发现是细胞外DNA网络的存在以及坏死和凋亡率低。

结论

CF痰中细胞外DNA水平升高与肺功能下降和住院增加有关。