Supplementary Material for: Endothelial Repair in Childhood Arterial Ischaemic Stroke with Cerebral Arteriopathy

<b><i>Background:</i></b> We have previously shown that recurrent arterial ischaemic stroke (AIS) in children with cerebral arteriopathy is associated with increased circulating endothelial cells and endothelial microparticles, consistent with ongoing endothelial injury. To date, however, little is known about endothelial repair responses in childhood AIS. We examined the relationship between the number and function of circulating endothelial progenitor cells (EPC), the levels of brain-derived neurotrophic factor (BDNF) and AIS recurrence. <b><i>Methods:</i></b> Flow cytometry was used to identify peripheral blood mononuclear cells positive for CD34/kinase insert domain-containing receptor (KDR). In a subgroup of patients (5 in each group selected at random), monocytic EPC function was assessed by colony-forming unit (EPC-CFU) capacity and incorporation into endothelial cell networks in Matrigel. BDNF was measured using ELISA. <b><i>Results:</i></b> Thirty-five children, aged 12 years (range: 5-16.5; 9 males), with AIS and cerebral arteriopathy were studied; 10 had recurrent AIS. CD34+/KDR+ cells were significantly higher in recurrent AIS compared to non-recurrent AIS patients (p = 0.005) and controls (p = 0.0002). EPC-CFU and EPC incorporation into endothelial cell networks were significantly reduced in recurrent compared to non-recurrent AIS patients (p = 0.04 and p = 0.01, respectively). Levels of BDNF were significantly higher in recurrent compared to non-recurrent AIS patients (p = 0.0008) and controls (p = 0.0002). <b><i>Conclusions:</i></b> Children with recurrent AIS and cerebral arteriopathy had increased circulating CD34+/KDR+ cells and BDNF consistent with an endothelial repair response. However, EPC function was impaired. Future studies are needed to examine whether suboptimal endothelial repair contributes to childhood AIS recurrence.