Research progress on the relationship between novel blood inflammatory markers and hemorrhagic transformation after ischemic stroke

Hemorrhagic transformation (HT) is one of the severe complications of ischemic stroke,which may occur either during the natural course or as a consequence of treatments such as thrombolysisand thrombectomy. HT is associated with poor prognosis after ischemic stroke and influences clinicaltreatment decisions. Disruption of blood⁃brain barrier (BBB) has been demonstrated as the main mechanismunderlying HT. Inflammatory responses contribute to this process by activating endothelial cells, recruitingimmune cells such as neutrophils and macrophages, and releasing inflammatory mediators includingproteases and reactive oxygen species, which further exacerbate vascular injury and BBB permeability,thereby promoting HT. Blood inflammatory markers may reflect these pathological processes and offervaluable biological information for early identification and risk stratification of HT. Classical inflammatorymarkers, such as matrix metalloproteinase⁃9 (MMP⁃9) and ferritin, have been demonstrated predictive valuefor HT. Recently increasing attention has been paid to investigate the mechanism and predictive potentialof novel markers, such as neutrophil gelatinase ⁃ associated lipocalin (NGAL), high ⁃ mobility group box 1(HMGB1) and nucleotide⁃binding oligomerization domain⁃like receptor protein 3 (NLRP3) inflammasome, forpredicting HT. This review focuses on the novel blood inflammatory markers and systematically describestheir correlation with HT, with the aim of providing a scientific basis for the mechanism investigation,accurate prediction and individualized therapeutic strategies of HT.