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Kidney Week

Abstract: PO2596

Buffy Coat Methylation Is Representative of Methylation Patterns in White Blood Cell Types in Normal Pregnancy

Session Information

Category: Women’s Health and Kidney Diseases

  • 2000 Women’s Health and Kidney Diseases

Authors

  • Ghamrawi, Ranine, Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • Milic, Natasa, Mayo Clinic Minnesota, Rochester, United States
  • Suvakov, Sonja, Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • White, Wendy, Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • Garovic, Vesna D., Mayo Clinic Minnesota, Rochester, Minnesota, United States
Background

Epigenetic changes through DNA methylation are increasingly identified in renal diseases and hypertensive disorders. Our previous studies identified an altered methylation pattern in preeclampsia compared to normotensive pergnancies. Epigenetic studies typically use buffy coat- a heterogenous cell population- that varies throughout pregnancy and could potentially interefere with DNA methylation results. The objective of the current study was to assess to what extent the buffy coat methylome is representative of the distinct cell types that it contains namely polymorphonuclear leukocytes(PMN) and lymphocytes(LYM) in normotensive pregnant women.

Methods

We performed a pairwise comparison of the differential methylation in the buffy coat, the polymorphonuclear fraction and the lymphocytic fraction drawn from the same individual in normotensive pregnant women (n=29) within the 24 hours prior to delivery. We analyzed 412481 cytosine-guanine (CpG) sites using an Illumina Human Methylation450 BeadChip.

Results

The three pairwise comparisons yielded a small number of probes that are differentially methylated. After multiple testing corrections, the smallest number of differentially methylated probes was found when comparing the buffy coat to the polymorphonuclear group (2.96%).Pathway analysis of the differentially methylated probes identified a matched process involved in leukocyte lineage.The differentially methylated CpG sites preferentially affected the open seas and shelf regions that have little effect on epigenetic regulation.

Conclusion

The buffy coat DNA methylation profile is representative of the PMN and LYM fractions on an Illumina Human Methylation450 BeadChip. The use of buffy coat is an acceptable approach for DNA sampling in DNA methylation studies and separation is only needed when studying lineage specific diseases.

Funding

  • Other NIH Support