Serum tight-junction proteins predict hemorrhagic transformation in ischemic stroke patients

To evaluate the significance of circulating tight-junction (TJ) proteins as predictors of hemorrhagic transformation (HT) in ischemic stroke patients.

We examined 458 consecutive ischemic stroke patients, 7.2% of whom had clinically evident HT. None of the patients was treated with thrombolytic drugs. Serum levels of standard markers of blood-brain barrier (BBB) breakdown (S100B, neuron-specific enolase), TJ proteins (occludin [OCLN], claudin 5 [CLDN5], zonula occludens 1 [ZO1]), and molecules involved in BBB disintegration (matrix metalloproteinase 9 and vascular endothelial growth factor [VEGF]) were assessed upon admission to the emergency department. A clinical deterioration caused by HT (cdHT) was defined as an increase of ≥4 points in the NIH Stroke Scale score in combination with a visible HT on a CT scan performed immediately after the onset of new neurologic symptoms.

Patients with cdHT had higher concentrations of OCLN, S100B, and the CLDN5/ZO1 ratio, and a lower level of VEGF than those without cdHT. CLDN5 levels also correlated with cdHT occurrence when estimated within 3 hours of stroke onset. We also demonstrated correlations between the levels of circulating TJ molecules and the level of S100B, which is a previously established marker of BBB disruption.

Analyzing serum levels of TJ proteins, like CLDN5, OCLN, and CLDN5/ZO1 ratio, as well as S100B and VEGF, is an effective way to screen for clinical deterioration caused by HT in ischemic stroke patients, both within and after the IV thrombolysis time window.