Mechanisms of Pregnancy Vascular Adaptations

PROCEDURE

Omental Biopsy

The surgeon and clinical care team will conduct the c-section to deliver the baby and the placenta as clinically indicated. After delivery, during the closing procedures, the surgeon will indicate a time for a participating Ob/Gyn physician on the study team to collect the omental bio-specimen. Omentum is frequently excised or removed for clinical reasons during surgical procedures. Omentum has small blood vessels within it that have been used for evaluation of vascular functional changes in research. The investigators wish to isolate one to three vessels of 5 to 7 cm length. The surgeon will then close and the clinical care team will resume their standard of care activities.

Quantify the vascular AT2R expression and vascular function in placental and omental vascular arteries in both preeclamptic and controlled pregnancies.

Time frame: 1 year

The researchers will measure the amount and distribution of vascular angiotensin II type 1 receptor (AT1R) and AT2R during normal human pregnancy and in preeclampsia. The researchers will assess if AT2R expression varies with severity of preeclampsia. Based on pilot data, the researchers expect decreased AT2R and increased AT1R protein levels in preeclamptic vs normotensive vessels.

To test if ex-vivo treatment of AT2R agonists reverses the endothelial dysfunction and improves vasoconstriction in the preeclamptic vessels.

Time frame: 1 year

The researchers will quantify vascular AT2R expression and vascular function in placental and omental arteries of preeclamptic vs normal pregnant women. Vascular function studies will also test if ex vivo treatment with AT2R agonist reverses endothelial dysfunction and vasoconstriction in preeclamptic vessels.

To test AT2R mediated mechanisms on endothelial derived hyperpolarizing factor, nitric oxide and prostacyclin pathway of vascular relaxation to examine AT2's role in vaso-relaxation and AT2R mediated vasoconstrictor pathway will be defined.

Time frame: 1 year

To test the AT2R-mediated mechanisms, endothelium-derived hyperpolarizing factor (EDHF), nitric oxide, and prostacyclin (PGI2) pathways of vascular relaxation and AT1R-mediated vasoconstrictor pathways will be determined. Also, the expression of endothelial nitric oxide synthase, its activity state, and signaling components of EDHF and PGI2 pathways, as well as nitrate/nitrite and PGI2 production and changes in membrane potential, will be measured

What is a clinical trial?

A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.

Is it safe to participate?

Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.

Will I be compensated?

Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.

Will I receive a placebo instead of treatment?

When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.

Can I leave a trial if I change my mind?

Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.

How long does a clinical trial last?

Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.