Hypertension and Circulating mRNA for 11β-Hydroxysteroid Dehydrogenase Type II

Alteration in methylation level at 11β-hydroxysteroid dehydrogenase type 2 gene promoter in infants born to preeclamptic women

Background

Preeclampsia reduces placental expression and activity of 11β-hydroxysteroid dehydrogenase type 2 (HSD11B2), leading to an increase in fetal glucocordicoids. The latter has been proposed to be associated with low birth weight and high risk of metabolic diseases in later life of the offspring. This investigation aims to delineate the alteration in methylation levels at CpG sites of HSD11B2 promoter.

Results

Methylation levels of HSD9-2, HSD9-3, HSD23-2 and HSD23-3 and the mean methylation level were significantly lower in preeclampsia than in normal pregnancy (P = 0.002, 0.031, 0.047 and 0.001, respectively and P < 0.001 in mean). The mean methylation level was significantly correlated with preeclampsia after the adjustment of birth weight, maternal age, gestational age at delivery and fetal gender (r = 0.325, P < 0.001).

Conclusions

Preeclampsia reduced methylation level at fetal HSD11B2 promoter. A positive correlation existed between HSD11B2 promoter methylation and preeclampsia. Our findings suggest that the methyaltion status of HSD11B2 promoter is a potentially accessible biomarker for preeclampsia. However, further studies are required to address the mechanisms of thehypomethylation at HSD11B2 promoter and the significance of the hypomethylation in the development of metabolic diseases of the fetals born to preeclamptic women.

Cell-free DNA in the blood as a solid tumor biomarker--a critical appraisal of the literature

Circulating cell-free DNA (cfDNA) has been suggested as a cancer biomarker. Several studies assessed the usefulness of quantitative and qualitative tumor-specific alterations of cfDNA, such as DNA strand integrity, frequency of mutations, abnormalities of microsatellites, and methylation of genes, as diagnostic, prognostic, and monitoring markers in cancer patients. Most of the papers that could be evaluated in this review resulted in a positive conclusion. However, methodical diversity without the traceability of data and differently designed and often underpowered studies resulted in divergent results between studies. In addition, the limited diagnostic sensitivity and specificity of cfDNA alterations temper the effusive hope of novel tumor markers, raising similar issues as those for other tumor markers. To validate the actual clinical validity of various cfDNA alterations as potential cancer biomarkers in practice for individual tumor types, the main problems of the observed uncertainties must be considered in future studies. These include methodical harmonization concerning sample collection, processing, and analysis with the traceability of measurement results as well as the realization of well-designed prospective studies based on power analysis and sample size calculations.