Secondary Brain Injury After Parenchymal Cerebral Hemorrhage in Humans: The Role of NOX2-Mediated Oxidative Stress and Endothelin-1

Abstract

Perihematomal hypoperfusion may lead to ischemic damage during intraparenchymal cerebral hemorrhage (ICH), resulting in worse prognosis. We aimed to (1) investigate the relationship between serum biomarkers related to oxidative stress and vasoactive substances and the occurrence of hypoperfusion and ischemic perihematomal lesions in ICH and (2) evaluate their correlation with the volumetric evolution of the hematoma and perihematomal edema. We enrolled 28 patients affected by ICH. Blood samples were collected at three different time points from symptom onset: T0, T1, and T2 (admission, 12-24 h, and 48-72 h, respectively), to measure endothelin-1 (ET-1), nitrites/nitrates (NO), soluble nicotinamide adenine dinucleotide 2 (NOX2)-derived peptide (sNOX2-dp), and asymmetric dimethylarginine (ADMA). Patients underwent brain MRI with perfusion study at T1 and MRI without perfusion at T2. 12 patients had ischemic perihematomal lesions at T1. A higher sNOX2-dp concentration at T0 was observed in patients with ischemic perihematomal lesions compared to those without (p = 0.051) and with a more severe perihematomal edema at T2 (p = 0.011). The ischemic perihematomal lesions development was also associated with an increased hematoma volume (p < 0.005), perilesional edema (p = 0.046), and greater midline shift (p = 0.036). ET-1 values at T1 were inversely correlated with hemorrhage volume at T2 (ρ = -0.717, p = 0.030). NOX2 activation may have a role in the development of ischemic perihematomal lesions. The association between higher ET-1 values and a lower hemorrhage volume could be related to the ET-1 vasoconstriction action on the ruptured vessel wall.

Keywords: endothelin-1; intracerebral hemorrhage; oxidative stress.

Figure 1

Representative neuroimaging of three patients. Patient 1: MRI at T2 reveals a large intraparenchymal hematoma within the right fronto-parietal lobe. (A) DWI sequences identify linear regions of restricted diffusion in the anterior perilesional area and the posteromedial region, with corresponding hypointensity on the ADC map (B), suggestive of ischemic injury (arrow). Additionally, small ischemic foci, measuring a few millimeters, are observed in the right frontal subcortical paramedian region and at the left frontal subcortical level (arrowheads). (D) Perfusion-weighted imaging (PWI) shows a significant increase in Tmax within the right parieto-occipital region and posterior temporal lobe, surrounding a large hematoma located in the right fronto-parietal lobe (C). Patient 2: MRI at T1 demonstrates a hematoma located in the right thalamo-capsular region with slight contralateral shift in the midline structures. (E) DWI imaging shows a perihematomal 5 mm² area of diffusion restriction, with corresponding hypointensity on the ADC map (F), consistent with a small recent ischemic lesion (arrow). Patient 3: MRI at T1 reveals a hemorrhagic focus in the left insula and basal ganglia, with slight lateral ventricle compression. (G) DWI imaging demonstrates a region of restricted diffusion in the posteromedial perilesional area, with corresponding hypointensity on the ADC map (H), suggestive of ischemic injury (arrow).

Figure 2

Median plasma levels (pg/mL) of sNOX2-dp at different time points (T0, T1, T2) by presence/absence of ischemic lesions at T1.

Figure 3

Correlations between ET-1 levels at T0 and T1 and hematoma volume at T2. The statistical test is the Spearman correlation test; black dots represent the single data points; ET-1 levels were measured in pg/mL; hematoma volume was measured in cm³.

Figure 4

Associations between ET-1 levels (pg/mL) at T0 and T2 and hematoma volume increase from T1 to T2.

Figure 5

Study timeline.