Introduction: The placenta is essential for fetal development and pregnancy prolongation. Its dysfunction can lead to short and long-term health consequences for mother and child. A subset of diseases resulting from placental dysfunction have been collectively termed placental-mediated diseases (PMD) - which includes the common and serious hypertensive disorder of pregnancy preeclampsia (PE), among others. PMDs are independent risk factors for maternal cardiovascular disease (CVD) in later life. This thesis presents a multi-pronged body of work, which includes: 1) A systematic review, aimed at summarizing the current state of knowledge on the risk for future maternal CVD after PMDs; 2) A cohort study, aimed at assessing the utility of placenta pathology examination at delivery to identify women at high lifetime risk for CVD following PE; and 3) An assessment of an immunohistochemistry screening panel for 3 placenta protein markers of interest, aimed at determining if these markers can accurately identify women deemed to be at high-risk for future CVD following a PE pregnancy.
Methods: 1) We searched 4 databases for observational studies evaluating clinical and biochemical markers of CVD risk and/or a subsequent calculated risk score based on these parameters in women with a history of PMD. We excluded interventional studies and studies measuring these outcomes during or prior to pregnancy. 2) A cohort study was established across two clinical sites (Kingston, Ottawa), in which patients with PE (N=85) underwent cardiovascular risk assessments at 6-months postpartum. The placentas from these pregnancies also underwent detailed placenta histopathology examination to determine the presence, absence, and severity of 35 distinct placental lesions. The associations between distinct placental lesions and estimated lifetime cardiovascular risk were evaluated by odds ratios (OR) and receiver operator curve analysis (ROC). 3) Immunohistochemistry (IHC) analysis was performed on placental samples from a subset of the previously described cohort (N=41; Ottawa site only). Protein expression for FLT-1, ENG, and CD68 was quantified. Using a multivariate logistic regression model, the association between placenta protein expression, with and without clinical and placenta pathology findings, and cardiovascular risk was assessed.
Results: 1) The search yielded 11,039 articles of which 104 met our inclusion criteria. All PMD types demonstrated evidence of increased CVD risk markers at varying timepoints postpartum. At least one study per PMD type had non-optimal measures of systolic blood pressure, BMI, and total cholesterol. 2) In the analysis of placenta pathology lesions within the cohort of individuals with PE, lesions of maternal vascular malperfusion (MVM) were found to be associated with elevated life-time risk for maternal CVD at 6 months postpartum (OR: 3.10[1.20-7.92]). We also found that adding these lesions to a logistic regression model improved the predictive accuracy for elevated maternal lifetime CVD risk (AUC: 73.0, sensitivity: 78.4%, specificity: 51.6%). 3) Individually, no significant differences were found in FLT-1, ENG, and CD68 expression between the individuals deemed to be at high and low-risk for lifetime CVD. Although, when added to a model that included placenta pathology lesions and clinical data the predictive accuracy for elevated maternal lifetime CVD risk increased (AUC: 1.0, sensitivity: 100%, specificity: 100%).
Conclusions: In conclusion, this thesis provides further evidence of the utility of assessing placenta features in the prediction of future maternal CVD. This is evidenced by the association between PMDs, placental pathology, and placental protein biomarkers with elevated risk profiles for lifetime CVD. Thus, specific placental phenotypes of PMDs may be at increased risk for CVD. The use of placental data should be further explored as a triage strategy to identify these high-priority of women following delivery.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/44405 |
| Date | 19 December 2022 |
| Creators | Mery, Erika |
| Contributors | Bainbridge-Whiteside, Shannon |
| Publisher | Université d'Ottawa / University of Ottawa |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
| Rights | Attribution 4.0 International, http://creativecommons.org/licenses/by/4.0/ |
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