Storage conditions and stability of global DNA methylation in placental tissue

Vilahur Chiaraviglio, Nadia, 1982-; Baccarelli, Andrea A.; Bustamante Pineda, Mariona; Agramunt, Silvia; Byun, Hyang-Min; Fernandez, Mariana F.; Sunyer Deu, Jordi; Estivill, Xavier, 1955-

doi:http://dx.doi.org/10.2217/epi.13.29

Storage conditions and stability of global DNA methylation in placental tissue

Citation

Vilahur N, Baccarelli AA, Bustamante M, Agramunt S, Byun HM, Fernandez MF et al. Storage conditions and stability of global DNA methylation in placental tissue. Epigenomics. 2013 Jun;5(3):341-8. DOI: 10.2217/epi.13.29

Abstract

AIM: The placenta is an informative and easily available tissue for many epidemiological studies. We analyzed the extent to which storage delay affects DNA methylation. MATERIAL & METHODS: Biopsies from two placentas were sequentially stored at -80°C after standing at room temperature for 30 min, 1 h, 2 h, 6 h and 24 h. Global DNA methylation was measured by bisulfite pyrosequencing of repetitive elements and the luminometric methylation assay. RESULTS: Small changes in global DNA methylation in relation to time-to-storage were observed by pyrosequencing, with a coefficient of variation (COV) of 2.49% (placenta 1) and 2.86% (placenta 2), similar to the mean technical variation observed for pyrosequencing (COV: 1.91 and 1.51%, respectively). A luminometric methylation assay yielded more variable results in the two placentas analyzed, both among time points (COV: 9.13 and 10.35%, respectively) and technical replicates (COV: 11.60 and 9.80%, respectively). CONCLUSION: Global DNA methylation is stable at room temperature. However, some techniques to measure methylation might be confounded by DNA degradation caused by a delay in storage.