Exercise and Carotid Artery Function in Metabolic Syndrome

Identifying Sex-specific Carotid Endothelial Dysfunction in Young Adults With Metabolic Syndrome

The purpose of this study is to determine 1) if young adults with metabolic syndrome display endothelial dysfunction of the internal carotid artery in a sex-specific fashion and 2) if this endothelial dysfunction can be acutely improved with a single bout of exercise. This will be achieved by testing internal carotid artery function before and after a 30-minute bout of moderate intensity exercise. 48 young adults with and without metabolic syndrome will be enrolled and will be on study for approximately 5.5 hours over 4 study visits.

The goal of this project is to determine if young MetSyn patients exhibit carotid endothelial dysfunction (ED) in a sex-specific manner and if exercise can acutely restore internal carotid artery (ICA) function.

The investigators will test this by first quantifying ICA endothelial function using an inhaled gas stressor (CO2) to acutely increase ICA shear rate (SR) and measuring the vascular responsiveness to this increased SR. Carotid endothelial function has never been tested in this way in patients with MetSyn before. Then, a 30 min bout of cycling exercise will be performed followed by the same gas stressor test to determine if ICA endothelial function can be acutely improved in MetSyn.

The aims and hypotheses are to:

• Aim 1: Determine if young adults with MetSyn exhibit carotid ED compared to healthy adults. Hypothesis: carotid ED will be present in young adults with MetSyn.
• Aim 2: Determine if sex differences exist in carotid endothelial function in MetSyn. Hypothesis: MetSyn will result in greater declines in carotid endothelial function in females.
• Aim 3: Determine if exercise yields an acute benefit on carotid endothelial function in young adults with MetSyn. Hypothesis: young adults with MetSyn will receive a greater increase in carotid endothelial function from a single bout of exercise than healthy adults.

Inclusion Criteria (MetSyn cohort):

• Waist circumference greater than 102 cm (males) or 82 cm (females)
• Triglycerides over 150 mg/dL
• HDL cholesterol less than 40 mg/dL (males) or 50 mg/dL (females)
• Blood pressure ≥130/85 mmHg
• Fasting plasma glucose over 110 mg/dL

Inclusion Criteria (Healthy cohort):

- meet age criteria

Exclusion Criteria:

• Current smoker, defined as more than 5 cigarettes over past 30 days

• Current diagnosis or history of:

  • peripheral vascular disease
  • hepatic disease
  • renal disease
  • lung disease
  • gastrointestinal disorders/bleeding
  • hematologic disease
  • stroke
  • myocardial infarction
  • coronary heart disease
  • congestive heart failure
  • heart surgery
  • sleep apnea
  • autoimmune diseases
  • traumatic brain injury, concussion, stroke, or seizures
  • Asthma
  • Polycystic ovarian syndrome

• Type II diabetes

• Currently pregnant or breastfeeding

• Current musculoskeletal injury Medication use known to influence cardiovascular function, other than oral contraceptives

• Hormonal contraceptive use, such as intrauterine device or hormonal implant use

• Participants with ICAs unsuitable for imaging, as assessed during the screening visit via doppler ultrasonography

Exclusion Criteria (healthy controls only):

• BMI greater than 25 kg/m2
• Blood pressure over 125/80 mmHg
• Meeting any MetSyn criteria listed for MetSyn cohort