Vascular and Neural Mechanisms of Chronic Leg Heating in Pregnant Women With Obesity
University of Texas Southwestern Medical Center
Summary
Obesity is a major risk factor for hypertensive disorders of pregnancy (HDP). The underlying mechanisms are largely unclear, but maternal vascular endothelial dysfunction is likely involved. Endothelial dysfunction in HDP could be attributed to 1) alterations in the L-arginine/nitric oxide (NO) pathway, and 2) an increase in endothelin-1 (ET-1). Additionally, augmented sympathetic vasoconstriction may also contribute to HDP. Chronic (repeated) whole-body heat exposure has been shown to increase NO bioavailability, decrease ET-1, and cause functional and structural adaptations in the vasculature. All these can improve vascular function, attenuate sympathetic (re)activity, lower blood pressure (BP), and reduce cardiovascular risk in non-pregnant individuals. Whether this is also true after regional (leg) heating in high-risk pregnant women is unknown. The investigators' central hypothesis is that chronic leg heating will be effective in improving vascular endothelial function and attenuating sympathetic vasoconstriction, leading to a reduction of the risk for HDP in pregnant women with obesity. The overarching goal of this proposal is to determine the vascular and neural effects of chronic leg heating in obese pregnancy. The study team plans to enroll pregnant women with obesity between 12-14 weeks of gestation and randomly assign them to either an intervention group or a control group (1:1 ratio). Participants in the intervention group will perform 16 weeks of home-based leg heating using a portable sauna blanket up to the hip (temperature of the blanket will be set at 65°C, 4 times/week, 45 min/session), whereas women in the control group will set the temperature of the blanket at 35°C at the same frequency and duration. Participants will be evaluated at baseline and then at 28-30 weeks of gestation. Aim 1 will determine the effects of chronic leg heating on maternal vascular function and surrogate markers of HDP. Aim 2 will determine the effects of chronic leg heating on sympathetic vasoconstriction and BP. Findings from this project will provide insight on the extent and potential mechanisms of how chronic leg heating works for improving vascular endothelial function and sympathetic vasoconstriction in pregnant women with obesity. Results obtained will set a foundation for future large multicenter clinical trials to determine the efficacy and generalizability of home-based leg heat therapy as a safe, ease-of-use, cost-effective, and non-drug approach for reducing the risk of HDP.
Description
Obesity is a major risk factor for hypertensive disorders of pregnancy (HDP). The underlying mechanisms are unclear, but maternal vascular endothelial dysfunction is likely involved. Endothelial dysfunction in HDP could be attributed in part to: 1) alterations in the L-arginine/nitric oxide (NO) pathway, and 2) an increase in endothelin-1 (ET-1). Conversely, augmented sympathetic vasoconstriction may also contribute to the development of HDP in women with obesity. Exercise training increases NO production, decreases ET-1, improves vascular function, attenuates sympathetic (re)activity, and red…
Eligibility
- Age range
- 18–45 years
- Sex
- Female
- Healthy volunteers
- Yes
Inclusion Criteria: * Women with overweight or obesity (self-reported pre-pregnancy body mass index ≥25 kg/m2) between 10-14 weeks of gestation and aged 18-45 years old will be enrolled. * Both normotensive and hypertensive (office sitting systolic BP 140-150 mmHg and/or diastolic BP 90-100 mmHg) pregnant women will be enrolled if they are not on any antihypertensive drug treatment. * We will enroll both nulliparous and multiparous women. * There is no restriction regarding race/ethnicity and socioeconomic status. * Women with a history of HDP will be allowed to participate. * Women taking lo…
Interventions
- OtherLeg heating
Participants will perform home-based leg heating using a portable sauna blanket set at different temperature.
Location
- UT Southwestern Medical Center; Institute for Exercise and Environmental MedicineDallas, Texas