Seraph 100: A New Tool to Decrease Elevated sFlt-1 in Preeclamptic Plasma? An In Vitro Analysis

Introduction: There is an unmet need to treat pre-eclampsia. To reverse endothelial dysfunction caused by elevated soluble fms-like tyrosine kinase -1 (sFlt-1) and therefore antagonizing placental growth factor (PIGF), extracorporeal techniques have been tested including unselective therapeutiic plasma exchange (TPE) and specific adsorprive devices. Since sFlt-1 binds to heparin, we hypothesized that the Seraph® 100, that consists of small polyethylene beads with endpoint attached heparin, lowers sFlT-1. Case Description: We used the plasma of a 33-year-old woman with severe preeclampsia during her 23rd week of gestation (blood pressure 190/110 mmHg, sFlT1/PIGF ratio 1433, platlets 36.000/µl, ALT 238 U/l). She and her son survived thanks to prolongation of the pregnancy by TPE. For the in vitro testing the Seraph® 100 was used in hemoperfusion mode. The Seraph® 100 adsorber clearance (CL) of sFlT-1 as calculated based on the plasma perfusion rate and extraction ratio (Cpre - Cpost) / Cpre, using the equation CLsFlT-1 = Qe * (Cpre - Cpost) / Cpre, where Qe is the effective plasma flow through the adsorber and Cpre and Cpost are pre and post adsorber concentrations, respectively [Figure]. Discussion: In vitro the Seraph® 100 lowered sFlT-1 by roughly 12 % in the plasma of our patient. The median plasma clearance of the Seraph® 100 for sFlT-1 based on seven pre- and post Seraph® 100 plasma levels at a pump speed of 200 mL/min was 8.9 (0.4 – 13.5) mL/min. Interestingly the clearance decreased during the treatment, which could reflect saturation. of the device. A total amount of 3.5 µg sFlT-1 had been removed. Further data are needed to clarify whether the Seraph® 100 decreases sFlT-1 to a clinically relevant degree.Serum levels of s-FLT-1 in a life size in vitro treatment with 4500 ml pre-eclamptic plasma using the Seraph® 100 on a Multifiltrate® Fresenius Medical Care machine in hemoperfusion mode at a pump speed of 200 mL/min for 120 min. "Arterial" levels refer to the plasma before entering the Seraph® 100 "Venous" levels refer to the plasma leaving the Seraph® 100.