Intensive Care Unit, Policlinico di Modena, University of Modena and Reggio Emilia, Modena, Italy.
Department of Medical and Surgical Sciences for Children and Adults, University of Modena and Reggio Emilia, Modena, Italy.
Front Immunol. 2020 May 5;11:768. doi: 10.3389/fimmu.2020.00768. eCollection 2020.
The activity and regulation of inflammasome is receiving increasing attention in septic shock. Moreover, there is a growing body of evidence suggesting that mitochondrial DNA (mtDNA) can play a role as biomarker of disease severity and even mortality both in adults and children in critically ill setting. However, no data are available on the amount of circulating mtDNA and inflammasome gene expression in multi-drug resistant (MDR) bacteria septic shock. For this reason, the aim of this study was to determine whether plasma mtDNA levels and inflammasome gene expression in monocytes could be related to severity in patients admitted to intensive care unit (ICU) with septic shock due to MDR pathogens. Peripheral blood mononuclear cells (PBMC) and plasma were isolated from up to 20 ml of venous blood by density gradient centrifugation in patients admitted to ICU with the diagnosis of septic shock due to MDR-bacteria. Then, CD14+ monocytes were sorted, and RNA and DNA were extracted. NLRP3, PYCARD, AIM2 and NAIP expression level was analyzed by RT-PCR. Plasma circulating mtDNA levels were quantified by digital droplet PCR. Basal and outcome characteristics of the patients were collected. Age-matched healthy subjects were chosen as controls. Nineteen patients with septic shock and 20 healthy subjects were enrolled in the study. A small trend toward an increased expression of inflammasome genes was observed in septic shock patients, who also displayed a marked tendency to an increased expression of IL-18 and IL-1β genes. Circulating mtDNA levels were significantly higher in septic shock patients if compared to healthy subjects, and patients who died in ICU were characterized by higher level of mtDNA if compared to those who were dismissed after 7 days. No correlations were found between mtDNA and inflammasome level and other clinical variables. Despite many limitations, our data suggest that in patients with septic shock caused by MDR pathogens the expression of main inflammasome genes was comparable to that of healthy patients without infection. Furthermore, our data evidence a possible role of mtDNA as a prognostic marker of severity in septic shock from MDR.
在脓毒性休克中，炎症小体的活性和调节受到越来越多的关注。此外，越来越多的证据表明，线粒体 DNA（mtDNA）可以作为疾病严重程度的生物标志物发挥作用，甚至在重症监护病房的成人和儿童中也可以作为死亡率的生物标志物。然而，目前尚无关于多药耐药（MDR）细菌脓毒性休克患者循环 mtDNA 量和炎症小体基因表达的相关数据。因此，本研究旨在确定单核细胞中循环 mtDNA 水平和炎症小体基因表达是否与 MDR 病原体引起的脓毒性休克患者的严重程度相关。 通过密度梯度离心从入住重症监护病房的 MDR 细菌引起的脓毒性休克患者的 20ml 静脉血中分离外周血单个核细胞（PBMC）和血浆。然后，分选 CD14+单核细胞，并提取 RNA 和 DNA。通过 RT-PCR 分析 NLRP3、PYCARD、AIM2 和 NAIP 的表达水平。通过数字液滴 PCR 定量检测血浆循环 mtDNA 水平。收集患者的基础和结局特征。选择年龄匹配的健康受试者作为对照。 本研究纳入了 19 例脓毒性休克患者和 20 例健康受试者。脓毒性休克患者的炎症小体基因表达呈轻度升高趋势，IL-18 和 IL-1β 基因表达也呈明显升高趋势。与健康受试者相比，脓毒性休克患者的循环 mtDNA 水平显著升高，与 7 天后出院的患者相比，死于 ICU 的患者的 mtDNA 水平更高。mtDNA 与炎症小体水平与其他临床变量之间未发现相关性。 尽管存在许多局限性，但我们的数据表明，在由 MDR 病原体引起的脓毒性休克患者中，主要炎症小体基因的表达与无感染的健康患者相当。此外，我们的数据表明 mtDNA 可能作为 MDR 脓毒性休克严重程度的预后标志物。
