Association between serum NLRP3 and malignant brain edema in patients with acute ischemic stroke

We aimed to explore the association of serum level of the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) and its related inflammatory biomarkers (hypoxia inducible factor-1α, cathepsin B, caspase-1 and matrix metalloproteinase-9) with malignant brain edema (MBE) in patients with acute ischemic stroke.

We prospectively enrolled patients with acute ischemic stroke admitted < 24 h from onset of symptoms. Brain CT was performed on admission and blood samples were collected. Repeated brain CT/MRI was performed < 7 days of admission to identify the presence of MBE, defined as neurological deterioration with imaging signs of midline shift or compressed basal cisterns. Logistic regression analysis was performed to assess the association between inflammatory biomarkers and MBE, adjusted for age and National Institutes of Health Stroke Scale (NIHSS).

200 patients (69.3 ± 14.3 years; male 55 %) were included for analysis, of whom 26 patients developed MBE (median time from stroke onset to MBE 32.5 h). Compared with patients without MBE, those with MBE had higher level of serum concentration of NLRP3 (median time from onset to blood collection 3 h, 1.85 ng/ml vs. 1.11 ng/ml, P = 0.026). NLRP3 level was positively correlated with NIHSS on admission (Spearman ρ = 0.18, P = 0.01) and the association between NLRP3 and MBE was attenuated (OR 1.47, 95 % CI 0.88-2.46, P = 0.138) after adjusting for age and NIHSS. There was no significant difference in other biomarkers between MBE and non-MBE groups.

There was a trend of association between a higher level of serum concentration of NLRP3 and an increased risk of MBE after ischemic stroke, possibly confounded by the severity of stroke, which is worth further validation in large cohort studies.