Objective: The goals of this study were to identify and quantify the presence of programmed cell death (apoptosis) in intracerebral hemorrhage (ICH) among human subjects. Recent evidence from laboratory models suggests that cell death in the perihematoma region may involve apoptosis.
Methods: Retrospective clinical and histological analyses were performed for patients with spontaneous ICH who underwent surgical evacuation. Quantification of apoptotic cells was performed in sections obtained from the perihematoma region from 12 patients with ICH and stained with the terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick-end labeling method. Necrosis was identified on the basis of morphological criteria, using hematoxylin and eosin staining.
Results: Evidence of apoptosis was present in surgical specimens obtained from 10 of the 12 patients. The mean number of apoptotic cells in the perihematoma region in each patient specimen was 38% (range, 0-90%). For five patients, more than one-half of the total cells observed were apoptotic. Apoptosis was observed in specimens obtained within 1 day, 2 days, and 5 days after the onset of symptoms. No terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick-end labeling-positive cells were observed in specimens from the two patients with cerebellar hematomas. The mean proportion of necrotic cells in the perihematoma region in each patient specimen was 25% (range, 0-100%). There was a prominent excess of apoptotic cells, in comparison with necrotic cells, for 6 of the 12 patients who underwent hematoma evacuation. For five other patients, similar proportions of apoptotic and necrotic cells were observed. Necrosis was the predominant finding for only one patient, who underwent late surgical evacuation on Day 5.
Conclusion: These observations suggest that apoptosis represents a prominent form of cell death associated with ICH in the perihematoma region. Further studies are required to define the mediators of apoptosis in ICH.