Introduction
Anti-neutrophil cytoplasm antibody-associated vasculitidies (AAV) represent a group of necrotizing small vessel vasculitidies that include Wegener’s granulomatosis, microscopic polyangiitis and Churg-Strauss-Syndrome. To date, little is known regarding endothelial cell survival and vessel regeneration in patients with AAV, despite the increasingly recognised role of vascular endothelial growth factor (VEGF) in mediating vessel repair.
Aim
Assess the role of sFlt1 in patients with AAV.
Anzeige
Material and methods
Were included 40 patients with PR3-AAV during active disease (n=20) or remission (n=20) and 23 patients with MPO-AAV during active disease (n=10) or remission (n=13). Eighteen additional PR3-AAV patients had paired serum samples drawn at the onset of the disease and at three months of follow-up.
Results
Serum levels of soluble Flt1 (sFlt1), a potent inhibitor of VEGF, are significantly increased during the acute phase of PR3-AAV (2592 ± 11347 pg/ml) and MPO-AAV (476 ± 4258 pg/ml) compared to controls (118 ± 269 pg/ml). sFlt1 levels decreased during disease remission but remained increased compared to controls in patients with PR3-AAV. sFlt1 serum levels correlated with serum levels of C5a, an anaphylatoxin released following complement activation. Serum from patients with acute PR3-AAV induced the release of sFlt1 by human monocytes in vitro, but failed to induce a similar effect on endothelial cells. Pre-treatment of monocytes with an anti-C5a receptor blocking antibody attenuated sFlt1 release. Serum from patients with acute AAV induced a disruption of blood flow in the chicken chorioallantoic membrane assay and this effect was prevented by incubating patients’ serum with an excess of human VEGF.
Conclusion
Our data indicate that a complement mediated-increase in sFlt1 occurs during acute AAV which leads to an “anti-angiogenic” state that hinders endothelial repair. “Pro-angiogenic” therapies, which would include complement activation inhibitors, may enhance endothelial repair during AAV and thus reduce renal vascular scarring.
Open AccessThis article is published under license to BioMed Central Ltd. This is an Open Access article is distributed under the terms of the Creative Commons Attribution 2.0 International License (https://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.