Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2TT, UK.
The Scar Free Foundation Centre for Conflict Wound Research, Queen Elizabeth Hospital Birmingham, Birmingham B15 2GW, UK.
Int J Mol Sci. 2024 Jun 29;25(13):7216. doi: 10.3390/ijms25137216.
Neutrophil extracellular traps (NETs) have a dual role in the innate immune response to thermal injuries. NETs provide an early line of defence against infection. However, excessive NETosis can mediate the pathogenesis of immunothrombosis, disseminated intravascular coagulation (DIC) and multiple organ failure (MOF) in sepsis. Recent studies suggest that high interleukin-8 (IL-8) levels in intensive care unit (ICU) patients significantly contribute to excessive NET generation. This study aimed to determine whether IL-8 also mediates NET generation in patients with severe thermal injuries. IL-8 levels were measured in serum samples from thermally injured patients with ≥15% of the total body surface area (TBSA) and healthy controls (HC). Ex vivo NET generation was also investigated by treating isolated neutrophils with serum from thermal injured patients or normal serum with and without IL-8 and anti-IL-8 antibodies. IL-8 levels were significantly increased compared to HC on days 3 and 5 ( < 0.05) following thermal injury. IL-8 levels were also significantly increased at day 5 in septic versus non-septic patients ( < 0.001). IL-8 levels were also increased in patients who developed sepsis compared to HC at days 3, 5 and 7 ( < 0.001), day 10 ( < 0.05) and days 12 and 14 ( < 0.01). Serum containing either low, medium or high levels of IL-8 was shown to induce ex vivo NETosis in an IL-8-dependent manner. Furthermore, the inhibition of DNase activity in serum increased the NET-inducing activity of IL-8 in vitro by preventing NET degradation. IL-8 is a major contributor to NET formation in severe thermal injury and is increased in patients who develop sepsis. We confirmed that DNase is an important regulator of NET degradation but also a potential confounder within assays that measure serum-induced ex vivo NETosis.
中性粒细胞胞外诱捕网 (NETs) 在热损伤的固有免疫反应中具有双重作用。NETs 提供了针对感染的早期防御线。然而，过度的 NETosis 可能介导脓毒症中的免疫血栓形成、弥散性血管内凝血 (DIC) 和多器官衰竭 (MOF) 的发病机制。最近的研究表明，重症监护病房 (ICU) 患者中高白细胞介素-8 (IL-8) 水平显著促进了过度的 NET 生成。本研究旨在确定 IL-8 是否也介导了严重热损伤患者的 NET 生成。测量了≥15%总体表面积 (TBSA) 的热损伤患者和健康对照者 (HC) 的血清样本中的 IL-8 水平。还通过用热损伤患者的血清或正常血清处理分离的中性粒细胞，并用和不用 IL-8 和抗 IL-8 抗体，来研究体外 NET 的生成。与 HC 相比，热损伤后第 3 天和第 5 天（<0.05）IL-8 水平显著升高。与非脓毒症患者相比，脓毒症患者第 5 天的 IL-8 水平也显著升高（<0.001）。与 HC 相比，在第 3 天、第 5 天和第 7 天（<0.001）、第 10 天（<0.05）以及第 12 天和第 14 天（<0.01），发生脓毒症的患者的 IL-8 水平也升高。结果显示，含有低、中或高水平 IL-8 的血清均能以 IL-8 依赖性方式诱导体外 NETosis。此外，通过防止 NET 降解，抑制血清中的 DNase 活性增加了 IL-8 诱导 NET 形成的活性。IL-8 是严重热损伤中 NET 形成的主要贡献者，在发生脓毒症的患者中增加。我们证实，DNase 是 NET 降解的重要调节剂，但也是测量血清诱导的体外 NETosis 时的潜在混杂因素。
