Acute Graft-Versus-Host Disease (aGVHD) is the most common early complication after allogeneic Hematopoietic Cell Transplantation (allo-HCT). We demonstrated endothelial dysfunction (ED) in association with allo-HCT. According to this data, aGVHD has been linked to an inflammatory process that may affect the endothelium.
To investigate the differential degree of endothelial damage in patients developing or not aGVHD, to identify potential biomarkers, and to explore the protective effect of defibrotide (DF) in this scenario. DF has orphan designation for GVHD prevention.
Patients blood samples were collected before allo-HCT, at day 0, and every week till day 28 after HCT. Plasma proteins (sTNFR1, sVCAM-1, VWF and ADAMTS-13) were measured as biomarkers of ED in individual samples from patients developing (GVHD, n=24), or not (NoGVHD, n=13), aGVHD. In
in vitro
assays, endothelial cells (EC) in culture were exposed to media containing pooled sera from patients to evaluate changes in the: a) expression of VCAM-1 and ICAM-1 on cell surfaces; b) presence of VWF on the extracellular matrix (ECM) and c) reactivity of the ECM towards platelets, under flow. The effect of DF was explored in the
in vitro
experiments by previous exposure of the EC (for 24h) followed by continuous incubation (100 μg/ml, added every 24h).
Levels of sTNFRI, sVCAM-1 and VWF in samples from group GVHD were significantly higher than in NoGVHD (increases of 100, 37 and 150% respectively, at diagnose, p<0.01). ADAMTS-13 activity and VWF levels were inversely related. In
in vitro
studies, cell surface expression of VCAM-1 and ICAM-1, presence of VWF and platelet adhesion on the ECM in response to GVHD samples were always superior (increases
vs
NoGVHD of 80, 40, 100 and 21%, respectively, at diagnose).
In vitro
exposure of EC to DF attenuated signs of endothelial injury reducing significantly (p<0.05) the expression of VCAM-1, ICAM-1 and VWF (reductions of 22, 30 and 30%, respectively) in the GVHD condition.
Our results demonstrate endothelial damage in association with aGVHD, as evidenced by elevated plasma levels of several biomarkers. The
in vitro
approach showed a marked proinflammatory and prothrombotic phenotype in association with aGVHD, which could be significantly prevented by defibrotide.
Chronic graft-versus-host disease in pediatric patients following hematopoietic cell transplantation