Circulating levels of thrombospondin-1 are decreased in HELLP syndrome

Preeclampsia is characterised by an imbalance of circulating pro- and anti-angiogenic factors. The syndrome of haemolysis, elevated liver enzymes and low platelet count (HELLP) develops mostly on the ground of preeclampsia, and one of its important features is the severe disturbance of the coagulation system, intravascular coagulopathy. Thrombospondin-1 (TSP-1) is derived from the endothelium and platelets, and exerts potent pro-thrombotic and anti-angiogenic effects. Our aim was to determine, whether its circulating levels are altered in preeclampsia and in HELLP syndrome.

We enrolled 45 pregnant women with early-, 43 with late-onset preeclampsia, 21 with HELLP-syndrome, 45 with uncomplicated pregnancy and 20 non-pregnant controls in our case-control study. TSP-1 levels were determined by enzyme-linked immunosorbent assay.

Circulating TSP-1 levels were lower in HELLP syndrome compared to all other study groups, while they were unaltered in preeclampsia compared to the control groups. There was a significant positive linear correlation between TSP-1 levels and platelet count in HELLP syndrome. In patients with more severe HELLP syndrome, TSP-1 levels were significantly lower compared to women suffering from a milder form of HELLP syndrome.

Circulating thrombospondin-1 levels are decreased in HELLP syndrome and they seem to reflect disease severity, lower levels representing a more severe state. Nevertheless, despite its potent anti-angiogenic effect, our results suggest that circulating TSP-1 does not play a significant role in the pathogenesis of preeclampsia.