Optimization Protocol of Fixation Method for Trophoblast Retrieval from the Cervix (TRIC): A Preliminary Study

Min Jin Lee, Soo Hyun Kim, Sung Han Shim, Hee Yeon Jang, Hee Jin Park, Dong Hyun Cha
2020 Diagnostics  
Extravillous trophoblast cells (EVTs) secreted by the uterine cavity may help overcome limitations associated with prenatal testing currently in use. EVTs are isolated using a routine safe liquid-based Pap test (called ThinPrep); however, the ThinPrep solution contains alcohol that hinders the isolation of intact EVTs. We compared the trophoblastic cell isolation efficiency of two different methods of fixation: Thinprep (pre-fixation method) and formalin (post-fixation method). We analyzed EVTs
more » ... from 20 pregnant women (5–20 weeks of gestation) who underwent invasive prenatal testing. The percentages of placental β-human chorionic gonadotropin (β-hCG)-expressing cells were calculated. The presence of XY chromosomes were used to confirm pure trophoblast cells by fluorescence in situ hybridization. The β-hCG-positive cells obtained from pre- and post-fixation were 66.4 ± 13.3% and 83.2 ± 8.1% (p = 0.003), respectively, and fluorescence-positive cells were 11.1 ± 2.1% and 23.8 ± 4.8%, respectively (p = 0.001). Post-fixation was found to be more efficient in isolating non-trophoblast cells than pre-fixation. For the successful clinical application of trophoblast retrieval and isolation from the cervix in prenatal genetic testing, each step should be optimized for consistent and reliable results.
doi:10.3390/diagnostics10050300 pmid:32422993 pmcid:PMC7277994 fatcat:5y2nrcaowbeb5htw3st5duk7um