Background: A stable intermediate during DNA demethylation, 5-hydroxymethylcytosine (5-hmC), raises questions about its function and distribution. Therefore, we tested whether 5-hmC exists in human adipose tissue depots and correlates with clinical variables.
Materials & methods: We measured the % 5-hmC content in both subcutaneous adipose tissue and visceral adipose tissue (VAT) from 81 individuals by using ELISA technology. To test for associations with several clinical variables we used paired students t-tests and linear regression analyses.
Results: We observed an average % 5-hmC content of 0.47% ± 0.093 in subcutaneous adipose tissue, while VAT (0.51% ± 0.122) is higher hydroxymethylated (p = 0.005). In the total cohort we observed a positive association of % 5-hmC in VAT with age (p = 0.034) and a negative relationship with low density lipoprotein-cholesterol (p = 0.008).
Conclusion: Our data suggest adipose tissue depot specific 5-hmC levels with higher levels in VAT.
Keywords: 5-hydroxymethylation; epigenetics; fat distribution; obesity; subcutaneous fat; visceral fat.