Circulating endothelial cells and endothelial progenitor cells in childhood primary angiitis of the central nervous system

Background

Primary angiitis of the central nervous system in children (cPACNS) is an inflammatory vasculitis that solely affects the CNS vessels in the absence of a systemic inflammatory process. Circulating endothelial cells (CECs) are increasingly described as biomarkers for tracking vascular injury [1]. Additionally, bone marrow-derived endothelial progenitor cells (EPCs) are thought to play a pivotal role in the regeneration of damaged endothelium. We describe the relationship of CECs and EPCs to clinical and/or radiological disease progression in cPACNS.

Materials and methods

16 children, median age 7 years old (range 1.8–17); 9 males with cPACNS were studied. Two groups were identified, according to radiological and/or clinical progression, or non progression at >6 months from diagnosis. CECs were isolated from whole blood using immunomagnetic bead extraction. EPCs were detected using flow cytometry and were defined as mononuclear cells triple positive for CD34/CD133/CD144 and CD34/CD133/VEGFR2.

Results

Median CEC count in progressive cPACNS was significantly raised to 480/ml (176–1152) compared to 36/ml (0–168) in non-progressive disease (p = 0.0007), 32/ml (0–152) in child control (p = 0.0050) and 24/ml (16–141) in patients with non inflammatory cerebrovascular pathology (p = 0.0016). CD34+CD133+CD144+ cells were significantly raised in patients with progressive disease compared to child controls (p = 0.005) and patients with non progressive disease (p = 0.03). There was a similar but non significant trend for EPCs expressing CD34/CD133/VEGFR2.

Conclusion

CECs can be used to track vascular injury due to cPACNS and differentiate progressive versus non-progressive cerebral vasculitis. We also demonstrated an increase in EPCs in progressive cPACNS, perhaps indicative of a compensatory reparative vasculogenic response.