No abstract

DNA repair is critical for proper embryogenesis, and altered expression of DNA repair genes has been associated with neural tube defects (NTDs). The expression of DNA repair enzymes may be controlled, in part, by methylation of the promoter region. To assess whether disturbed promoter methylation pattern increases the incidence of NTDs, we employed methylation specific-multiplex ligation-dependent probe amplification (MS-MLPA) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) to quantify the methylation levels of multiple promoter CpG sites in normal human embryos and embryos with NTDs. Of the total seven DNA repair genes, two genes (MGMT, MSH6) were examined as having disturbed methylation levels by MS-MLPA kit, while only one gene was confirmed with a significant alternated methylation pattern by MALDI-TOF MS. In our research, methylation profiling of the DNA repair gene O (6)-methylguanine-DNA methyltransferase (MGMT) showed gender difference in embryogenesis. Comparison of MGMT promoter methylation revealed that hypomethylation was associated with an increased risk for cephalic malformations, especially with female embryos (Adjusted Odds Ratio = 8.250). The majority of individual CpG units within the promoter demonstrated hypomethylation. Meanwhile, the expression of MGMT was proven to increase significant in female cases. These results underscore the role of stable promoter methylation in the DNA repair enzymes MGMT for proper embryogenesis.

Single ventricle palliation relies on the pulmonary vasculature accommodating non-pulsatile systemic venous return. Mean pulmonary artery pressure (MPAP) and indexed pulmonary vascular resistance (PVRi) are two measures that impact pulmonary blood flow following bidirectional cavopulmonary connection (BCPC). The purpose of the study was to determine which hemodynamic features are associated with adverse outcomes after BCPC. Pre-operative hemodynamic data and post-operative morbidity and mortality in 250 patients undergoing BCPC at a single center from 2008 to 2014 were reviewed. Patients were then separated into 5 physiologic states based on MPAP, PVRi, and degree of pulmonary to systemic blood flow (Q:Q). There were 9 (3.6%) deaths, and 49 patients (20%) sustained major morbidity. An ROC curve identified MPAP > 16 mmHg as an inflection point. Pre-BCPC sildenafil and oxygen use, ventricular dysfunction, and MPAP > 16 mmHg (OR 4.1 [95% CI 1.8-9.2]) were independently associated with morbidity. MPAP > 16 mmHg (OR 6.7 [95% CI 1.6-28]) and pre-BCPC oxygen use were associated with hospital mortality. PVRi was not associated with morbidity or mortality. Of the five physiologic states, patients with high MPAP, low PVRi, and low Q:Q fared the worst, with the highest risk of major morbidity (OR 8.6 [3.0-24.9]) and highest risk of mortality (OR 8.0 [1.5-41.3]) when compared to their reference groups (low MPAP, low PVRi). Elevated MPAP, need for pre-operative oxygen support, sildenafil use, and systemic ventricular systolic dysfunction predict morbidity following BCPC. Specifically, patients with elevated MPAP not due to elevated PVRi or pulmonary blood flow had the highest risk of morbidity and mortality.