Soluble CD163 in intracerebral hemorrhage: biomarker for perihematomal edema

Objective Patients with intracerebral hemorrhage (ICH) may elaborate varying degrees of perihematomal edema (PHE), requiring closer monitoring and a higher intensity of treatment. Here, we explore whether the soluble form of CD163, a scavenger receptor responsible for hemoglobin sequestration, can serve as a prognostic biomarker of PHE development and poor outcome after ICH. Methods Our study cohort was comprised of 51 primary age- and sex-matched ICH patients with moderate-sized, hypertensive deep hemorrhages. Patients were part of a prospective ICH registry cataloguing admission data along with functional outcomes. We measured sCD163 levels in serial serum and cerebrospinal fluid (CSF) samples obtained at prespecified timepoints. Descriptive statistics, including a generalized estimating equation for longitudinal data, were used to analyze sCD163 in relation to ICH outcomes. Results Acute serum sCD163 (<48 h postictus) was significantly elevated in ICH patients compared to both acute neurological event controls (P = <0.001) and healthy controls (P = 0.003). As predicted, acute serum sCD163 levels were significantly associated with both hematoma volume expansion (P = 0.009) and PHE expansion (P = 0.002). Further examination determined that patients with high PHE expansion had poorer modified Rankin Scale scores at discharge (P = 0.024), and circulating sCD163 levels were found to be significantly lower in patients with high-level PHE expansion. Interpretation Acute sCD163 levels may be a useful biomarker for the acute identification of patients at risk for hematoma expansion, perihematomal edema expansion and poorer short-term outcomes.