Objective: To study the bone marrow microvessel density (MVD) and vascular endothelial growth factor (VEGF) expression and their clinical significance in patients with aplastic anemia (AA).
Methods: Bone marrow biopsies in 51 newly diagnosed patients with AA were evaluated the MVD and VEGF expression by immunostaining with anti-factor VIII related antigen and VEGF monoclonal antibodies at regular time points after immunosuppressive therapy (IT).
Results: The mean bone marrow MVD in AA group was 5.5 +/- 3.5, being significantly lower than that in normal control group (8.7 +/- 3.4, P < 0.05). MVDs of SAA and NSAA patients were 7.4 +/- 2.9 and 4.3 +/- 3.4, respectively, being significantly different (P < 0.01). The VEGF expression in AA group was significantly lower than that in control group [(6.7 +/- 8.4)% vs (14.7 +/- 6.1)%, P < 0.01], but there was no difference between SAA and NSAA. Bone marrow MVD and VEGF were significantly increased after IT in 22 responded AA patients.
Conclusion: Bone marrow MVD and VEGF expression are low in AA patients which may be one of pathophysiologic mechanisms of bone marrow failure in AA. Proangiogenic and ameliorating microcirculation agents together with IT might accelerate the recovery of hematopoiesis in AA patients.