Bibliographic record
Abstract
Preeclampsia is a leading cause of maternal and fetal death throughout the world. It is caused by placental dysfunction and clinically characterized by hypertension and other adverse outcomes. Early-onset preeclampsia (EOPET) is a severe form of the disorder. Despite much investigation, the underlying biology of EOPET is unclear. It is known that disrupted oxygen delivery and altered cellular differentiation are characteristics of preeclampsia placentas, and that this likely has an effect on the placental molecular profile. This thesis primarily investigates DNA methylation, a key component in regulating gene expression, in placentas and cellular states related to EOPET. Investigating placental cells exposed to hypoxia, we found 147 CpG sites in cytotrophoblast whose DNA methylation was significantly altered by exposure to hypoxia for 24 hours. Many of these sites overlapped with the 223 CpG sites that were altered between normoxic cytotrophoblast and syncitiotrophoblast, however the change was in the opposite direction (hypomethylated vs. hypermethylated), implying hypoxia can molecularly prevent differentiation in trophoblast cells. Expanding on these findings to look at DNA methylation in placental tissue from preeclampsia pregnancies, we found significant differences at 282 CpG sites. Several of these differences occurred in genes that have functional relevance for the development of EOPET. Many of the candidate genes also showed differential gene expression in preeclampsia placentas. To investigate the utility of these candidate CpGs as 1st trimester EOPET biomarkers, placentas with increased susceptibility to preeclampsia (trisomy 16) were investigated across gestational ages. There were many DNA methylation differences in 3rd trimester trisomy 16 placentas that were shared with chromosomally normal 3rd trimester EOPET placentas, suggesting a common molecular profile of preeclampsia prone placentas, regardless of etiology. Comparing 1st trimester trisomy 16 against 3rd trimester trisomy 16, we found 77 CpG sites differentially methylated in both conditions, and further found 3 changes in first trimester trisomy 16 shared with 3rd trimester EOPET. Overall, these studies have identified several molecular changes in EOPET and related conditions that provide insight into the biology of the disorder while also providing novel candidates to investigate further in a clinical setting.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".