Vascular Effects of Acute Sodium (VEAS) Study
- Conditions
- Sodium ExcessRacial DisparitiesBlood PressureCardiovascular Risk Factor
- Interventions
- Other: Acute Salt (sodium chloride)
- Registration Number
- NCT04244604
- Lead Sponsor
- Indiana University
- Brief Summary
This IRB will cover a current clinical trial (NCT04244604) that was started at Auburn University (AU IRB#19-390), the Principal Investigator's prior institution, and is supported by his NIH Career Development Award (NHLBI K01HL147998).
About nine out of ten Americans overconsume dietary salt. Compared to other racial groups, Black individuals are more prone to salt-sensitive hypertension and negative cardiovascular conditions associated with high salt intake. However, there is a critical need to determine the reasons behind and mechanisms that contribute to these racial disparities. Both acute (single meal) and chronic high-dietary sodium cause small but important increases in blood sodium concentration that are associated with altered blood pressure regulation and blood vessel dysfunction. However, racial differences in these measures have not been examined. This is important because Black individuals generally exhibit lower circulating concentrations of hormones (e.g., renin, aldosterone, angiotensin 2) that buffer changes in body sodium to regulate blood pressure, and this could make them more vulnerable to the negative effects of a high-sodium meal.
Therefore, the purpose of this study is to determine whether there are racial differences in blood pressure regulation and blood flow after a high-sodium meal. The investigators will assess blood pressure regulation, blood vessel stiffness, and the blood vessel's ability to dilate before and after a high-salt meal and a low-salt control meal (both meals are low-salt tomato soup with varied added salt). The investigators will also collect blood and urine to measure sodium and determine biochemical changes that may be contributing to racial differences in cardiovascular function.
- Detailed Description
The investigators have previously used a high-sodium saline infusion to increase blood sodium and consequently increase blood pressure in Black and White individuals. The investigators' prior data suggest that increased blood sodium concentrations result in larger blood pressure elevations for a given elevation in blood sodium levels in Black compared to White adults. In this proposal, the investigators are seeking to translate these previous findings using a single high-salt meal (up to 2500 mg of sodium; similar to a few slices of pizza or a sandwich/burger and side dish). Our primary aims are to determine if the high-sodium meal causes greater 1) blood pressure dysregulation 2) decreases in blood vessel function and 3) larger changes in blood sodium in Black compared to White individuals. Other potential questions that could be determined include aging differences or an influence of fitness. The investigators will not exclude other races/ethnicities as the project will also determine the response of other minority groups (e.g. Asian or Latine/Hispanic adults) to a high-salt meal.
Recruitment & Eligibility
- Status
- RECRUITING
- Sex
- All
- Target Recruitment
- 100
- Are between the ages of 19-75.
- Have blood pressure no higher than 150/90 mmHg.
- Have a BMI below 35 Kg/m2 (otherwise healthy)
- Free from metabolic disease (diabetes or renal disease), pulmonary disorders (e.g., COPD & cystic fibrosis), and cardiovascular disease (peripheral vascular, cardiac, or cerebrovascular).
- Do not have any precluding medical issues that prevent participants from exercising (i.e., cardiovascular issues, or muscle/joint issues including painful arthritis) or giving blood (e.g., blood thinners).
- Are not currently smoking, using smokeless tobacco, nor smoked within the past 12 months.
- High blood pressure - greater the 150/90 mmHg
- Low blood pressure - less than 90/50 mmHg
- History of cardiovascular disease
- History of cancer
- History of diabetes
- History of kidney disease
- Obesity (BMI > 30 kg/m2)
- Smoking or tobacco use
- Current pregnancy
- Nursing mothers
- Communication barriers
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- CROSSOVER
- Arm && Interventions
Group Intervention Description Low Sodium Meal (140 mg sodium) Acute Salt (sodium chloride) Participants will have sympathetic nerve activity, vascular function, blood pressure and blood samples (from intravenous catheters) assessed before and after a low sodium meal (140 mg sodium) which will serve as the control condition to demonstrate whether or not observed changes are due to high sodium or occur irrespective of sodium in the postprandial state. High Sodium Meal (2500 mg sodium) Acute Salt (sodium chloride) Participants will have sympathetic nerve activity, vascular function, blood pressure and blood samples (from intravenous catheters) assessed before and after a high sodium meal (2500 mg sodium).
- Primary Outcome Measures
Name Time Method Changes in flow-mediated dilation (FMD) Before, 30 minutes, and one hour after soup, both conditions (high- and low- salt) Flow-mediated vasodilation will be assessed using continuous measures of brachial artery diameter and velocity via duplex Doppler ultrasound (Hitachi Arietta 70). The brachial artery will be imaged in the longitudinal plane proximal to the medial epicondyle using a high-frequency (6-12 MHz) linear-array probe. The ultrasound probe will be stabilized using a custom-built clamp. Shear rate (sec-1) will be calculated as \[(blood flow velocity (cm\*s-1) \*4)/blood vessel diameter (mm)\] The image will be recorded throughout a 60-s baseline, a 300-s ischemic stimulus (250 mmHg), and 180 seconds post deflation. FMD will be expressed as % dilation (final diameter-baseline diameter/baseline diameter x 100) and also normalized to the shear stimulus. Allometric scaling will be used if appropriate, including if there are baseline differences in artery diameter by race or condition.
Changes in indices of arterial stiffness Before 30 minutes, and one hour after soup, both conditions (high- and low- salt) The investigators will use the SphygmoCor XCEL system to assess pulse wave analysis (PWA) and pulse wave velocity (PWV). A high-fidelity strain-gauge transducer is used to obtain the pressure waveform at the carotid and radial pulse. Distances from the carotid artery sampling site to the femoral artery (upper leg instrumented with a thigh cuff for oscillometric sphygmomanometry), and from the carotid artery to the suprasternal notch will be recorded. The investigators will also assess forward and reflective wave magnitudes. PWV will be expressed as cm/s and PWA will be expressed as % (calculated as augmentation pressure divided by the pulse pressure).
Changes in blood pressure reactivity Before and one hour after soup, both conditions (high- and low- salt) The investigators will measure systolic and diastolic pressure using photoplethysmography at the finger. Systolic and diastolic blood pressure will be assessed at rest and during handgrip exercise. Blood pressure reactivity will be expressed as a change in pressure (mmHg) from baseline to a predetermined time during the stressor (e.g., minute one average and minute two average).
Changes in blood biomarkers of nitric oxide bioavailability Before, 30 minutes, and one hour after soup, both conditions (high- and low- salt) The investigators will measure nitric oxide metabolites (nitrate and nitrite nanomolar concentration).
Changes in circulating reactive oxygen species Before, 30 minutes, and one hour after soup, both conditions (high- and low- salt) The investigators will use electron paramagnetic resonance to measure reactive oxygen species (spectra units) in whole blood samples treated with a spin probe.
Changes in circulating inflammatory cytokines Before, 30 minutes, and one hour after soup, both conditions (high- and low- salt) The investigators will measure inflammatory markers (nano- or picograms per deciliter) via enzyme linked immunoabsorbent assays.
- Secondary Outcome Measures
Name Time Method Objective sleep duration and quality Baseline (pre-intervention) Philips actiwatch spectrum will be used to quantify sleep duration. Participants will wear the watch units for 7 days. The investigators will assess qualitative sleep scores and cross-check actigraphy wear times with a sleep diary.
Subjective Sleep duration and quality Baseline (pre-intervention) The investigators will use the Pittsburgh Sleep Quality Index to asses sleep duration and perceived sleep quality reflective of the one month period leading into the study.
Physical activity Baseline (pre-intervention) Participants will wear an ActiGraph GT3X accelerometer for seven days to objectively quantify steps per day and metabolic equivalents per day.
Cardiorespiratory fitness Baseline (pre-intervention) The investigators will use indirect calorimetry to measure the participant's maximal oxygen consumption (VO2max) during incremental exercise on a treadmill. The investigators will use a Parvo TrueOne metabolic cart and Woodway treadmill.
Mental health - social anxiety Baseline (pre-intervention) The investigators will administer the Liebowitz Social Anxiety Scale. The scale starts at 0 (none) and ends at 3 (severe) for 24 questions related to anxiety and avoidance, and a cumulative score is calculated.
Mental health - depression Baseline (pre-intervention) The investigators will administer the Beck's Depression Inventory. The scale starts at 0 and ends at 3 for 21 questions related to depression.
Habitual dietary intake Baseline (pre-intervention) The investigators will instruct participants to complete a diet log for 6 days which will be operationalized with Nutrition Data System for Research (NDSR).
Trial Locations
- Locations (2)
Indiana University School of Public Health
🇺🇸Bloomington, Indiana, United States
Auburn University
🇺🇸Auburn, Alabama, United States