Increased serum levels of anti-angiogenic factors soluble fms-like tyrosine kinase and soluble endoglin in sickle cell disease.

The anti-angiogenic factors soluble fms-like tyrosine kinase (sFlt)-1 and soluble endoglin (sEng) have been shown to be of importance in angiogenesis by sequestering and inhibiting vascular endothelial growth factor, placenta-like growth factor and transforming growth factor-beta(1) signaling. Given the potential role of angiogenesis in the pathophysiology of sickle cell disease (SCD)-related complications, serum levels of sFlt-1 and sEng were determined in SCD patients and controls. Both sFlt-1 (p = 0.002) and sEng (p = 0.004) were elevated in patients during clinically asymptomatic SCD with no further increment during painful crisis. These data suggest that sFlt-1 and sEng may be important in the regulation of angiogenesis in SCD.