Tuz Ali Ata, Hoerenbaum Nils, Ulusoy Özgür, Ahmadi Adel, Gerlach Alana, Beer Alexander, Kraus Andreas, Hasenberg Anja, Hagemann Nina, Hermann Dirk M, Gunzer Matthias, Singh Vikramjeet
Institute for Experimental Immunology and Imaging, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
Department of Neurology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
Front Immunol. 2025 Jan 8;15:1502346. doi: 10.3389/fimmu.2024.1502346. eCollection 2024.
Post-stroke early activation of neutrophils contributes to intensive neuroinflammation and worsens disease outcomes. Other pre-existing patient conditions can modify the extent of their activation during disease, especially hypercholesterolemia. However, whether and how increased circulating cholesterol amounts can change neutrophil activation responses very early after stroke has not been studied. In this study, we investigated the effect of high-fat diet (HFD) induced hypercholesterolemia on neutrophil activation and stroke outcome. Mice were fed with HFD or normal diet (ND) for six weeks and then induced stroke by transient occlusion of the middle cerebral artery. The activation receptors on immune cells and plasma levels of cytokines were analyzed using flow cytometry. The amount of plasma neutrophil extracellular traps (NETs) was measured using citH3-DNA complex ELISA. We found that HFD-induced cholesterolemia increased the number of circulating and splenic neutrophils in stroke mice but reduced bone marrow neutrophils compared to sham controls. After stroke neutrophils in HFD mice expressed higher levels of activation markers Ly6G and PSGL-1 (CD162) compared to ND mice. In addition, stroke led to an increased expression of the activation markers Ly6C and CD68 on monocyte/macrophages (MΦ) in HFD mice but not in ND mice. Compared to ND, HFD increased plasma levels of the proinflammatory cytokines TNF-α, IL-6, IL-23, and MCP-1 in stroke mice. Remarkably, HFD mice showed higher amounts of circulating NETs, brain-infiltrated neutrophils, and larger infarcts after stroke compared to ND mice. The existence of hypercholesterolemia with a stroke can trigger a stronger activation of neutrophils and MΦ, causing deteriorating disease outcomes.
中风后中性粒细胞的早期激活会导致强烈的神经炎症并恶化疾病预后。其他预先存在的患者状况可改变疾病期间中性粒细胞的激活程度，尤其是高胆固醇血症。然而，循环胆固醇水平升高是否以及如何在中风后极早期改变中性粒细胞的激活反应尚未得到研究。在本研究中，我们调查了高脂饮食（HFD）诱导的高胆固醇血症对中性粒细胞激活和中风结局的影响。将小鼠喂食HFD或正常饮食（ND）六周，然后通过大脑中动脉短暂闭塞诱导中风。使用流式细胞术分析免疫细胞上的激活受体和细胞因子的血浆水平。使用citH3-DNA复合物ELISA测量血浆中性粒细胞胞外陷阱（NETs）的量。我们发现，与假手术对照组相比，HFD诱导的胆固醇血症增加了中风小鼠循环和脾脏中的中性粒细胞数量，但减少了骨髓中的中性粒细胞数量。与ND小鼠相比，中风后HFD小鼠的中性粒细胞表达更高水平的激活标志物Ly6G和PSGL-1（CD162）。此外，中风导致HFD小鼠而非ND小鼠的单核细胞/巨噬细胞（MΦ）上激活标志物Ly6C和CD68的表达增加。与ND相比，HFD增加了中风小鼠促炎细胞因子TNF-α、IL-6、IL-23和MCP-1的血浆水平。值得注意的是，与ND小鼠相比，HFD小鼠中风后循环NETs、脑内浸润的中性粒细胞数量更多，梗死面积更大。中风合并高胆固醇血症的存在可引发中性粒细胞和MΦ更强的激活，导致疾病预后恶化。
