Magnapure isolation kit and instrument

In the STORK study, PBMC was isolated from venous blood using BD Vacutainer CPT Tubes (BD, NJ) at weeks 22–24, 36–38, and at 5-year follow-up and stored at − 70 °C until extraction. RNA was extracted using Magnapure Isolation Kit and instrument (Roche Life Science, Penzberg, Germany) at weeks 22–24 and with Magmax isolation kit and instrument (Applied Biosystems, Carlsbad, CA) at weeks 36–38 and at follow-up, due to change in instruments at the laboratory over the years, as previously published¹⁹ . RNA available from PBMC in this cohort included 189 controls/32 PE at 22–24 weeks, 194 controls/24 PE at 36–38 weeks and 213 controls/10 PE at 5-year follow-up.

DNA was extracted from the PBMC isolated from venous blood at weeks 22–24 (controls n = 186, PE n = 31) using Magnapure Isolation Kit and instrument (Roche Life Science) and using a salting out procedure^{21 (link)} of EDTA blood collected at the 5-year follow-up visit in the STORK study (controls n = 206, PE n = 10). Equal amounts of DNA (2 ng/μL) were used to measure telomere length by PCR using telomere‐specific primers relatively quantified to the single‐copy gene RPLP0 (Table 1, Supplemental File). All samples were run in duplicates. Quantification was performed using SYBR Green PCR Fast Mix (Quantabio, Beverly, MA) on an ABI Prism 7900 (Applied Biosystems).