From UCSD: Banking placental tissue

Placenta. 2014 Jun 6. pii: S0143-4004(14)00197-0. doi: 10.1016/j.placenta.2014.05.005. [Epub ahead of print]

Banking placental tissue: An optimized collection procedure for genome-wide analysis of nucleic acids.

Wolfe LM1, Thiagarajan RD1, Boscolo F2, Taché V3, Coleman RL4, Kim J5, Kwan WK1, Loring JF4, Parast M5, Laurent LC6.

Author information

• 1Department of Reproductive Medicine, University of California San Diego, San Diego, CA 92103, USA.
• 2Department of Reproductive Medicine, University of California San Diego, San Diego, CA 92103, USA; Department of Chemical Physiology, Center for Regenerative Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA.
• 3Department of Reproductive Medicine, University of California San Diego, San Diego, CA 92103, USA; Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, University of California Davis, Sacramento, CA 95817, USA.
• 4Department of Chemical Physiology, Center for Regenerative Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA.
• 5Department of Pathology, University of California San Diego, San Diego, CA 92103, USA.
• 6Department of Reproductive Medicine, University of California San Diego, San Diego, CA 92103, USA. Electronic address: louise.laurent@gmail.com.

Abstract

INTRODUCTION:

Banking of high-quality placental tissue specimens will enable biomarker discovery and molecular studies on diseases involving placental dysfunction. Systematic studies aimed at developing feasible standardized methodology for placental collection in a typical clinical setting are lacking.

METHODS:

To determine the acceptable timeframe for placental collection, we collected multiple samples from first and third trimester placentas at serial timepoints in a 2-h window after delivery, simultaneously comparing the traditional snap-freeze technique to commercial solutions designed to preserve RNA (RNAlater™), and DNA (DNAgard®). The performance of RNAlater for preserving DNA was also tested. Nucleic acid quality was assessed by determining the RNA integrity number (RIN) and genome-wide microarray profiling for gene expression and DNA methylation.

RESULTS:

We found that samples collected in RNAlater had higher and more consistent RINs compared to snap-frozen tissue. Similar RINs were obtained for tissue collected in RNAlater as large (1 cm3) and small (∼0.1 cm3) pieces. RNAlater appeared to better stabilize the time zero gene expression profile compared to snap-freezing for first trimester placenta. DNA methylation profiles remained quite stable over a 2 h time period after removal of the placenta from the uterus, with DNAgard being superior to other treatments.

DISCUSSION AND CONCLUSION:

The collection of placental samples in RNAlater and DNAgard is simple, and eliminates the need for liquid nitrogen or a freezer on-site. Moreover, the quality of the nucleic acids and the resulting data from samples collected in these preservation solutions is higher than samples collected using the snap-freeze method and easier to implement in busy clinical environments.