LABORATORY PROCEDURES

Endothelial Function (EF) may be a more "real" risk factor for heart disease than cholesterol, hypertension, or physical inactivity. This lab has multiple purposes:

1. Explore the measurement of endothelial function
2. Distinguish the difference of brachial artery diameters among different sexes
3. Identify the effect of exercise on endothelial function.
4. Examine the concept of Flow Mediated Dilation (FMD) in the clinical setting.

In this lab, one subject (one woman and one man from each lab section). Endothelial function, as measured by brachial artery reactivity will be measured

• baseline rest
• immediately following one exercise session (40 min @ 60%)
• 30 min post
• 60 min post
• 90 min post

During the exercise, each member of the group will take blood pressures, heart rates and VO₂. After the completion of the lab you will break up into groups to analyze the data and complete the questions. The two primary activities of this lab are:

• Diameter of your Artery
• Flow Mediated Dilation
• Exercise
  

2 to10cm above your elbow. Once a clear image is obtained, resting blood flow velocity will be measured by the ultrasound, and three pictures will be captured within 60 seconds by the ultrasound. The diameter of the artery will then be measured.

Flow Mediated Dilation

After baseline measurements are obtained, the second blood pressure cuff wrapped around the forearm of the right arm will be inflated to 250 mm Hg to stop blood flow to your lower arm for 5 minutes. After the cuff is deflated repeated ultrasound measurements as described above will be taken at 45 seconds, 60 seconds and 90 seconds. Flow mediated dilation will be expressed as a percentage of the artery expansion from the increased blood flow, compared to the baseline value. Flow-Mediated Dilation will be measrued:

• Baseline
• Immediately following exercise
• 30 min following exercise
• 60 min following exercise
• 90 min following exercise

Exercise

One woman and one man will perform 40 min of treatmill walking at approximately 65-70% of maximal heart rate. Variables to be measrued at baseline are

• heart rate
• blood pressure

Variables to be measrued during the exericse are:

• heart rate (each min)
• blood pressure (every 5 min)
• oxygen uptake (min 5-7)

Variables to be measured in recovery are:

• heart rate (every min for 5 min)
• blood pressure (immediate, 1, 3 and 5 min)

Click here to download the lab write-up.

Click here to download the data form.
Turn this data form in to Dr. Wallace as soon as you collect the data.

Endothelial Function Lab Questions (Total 80 pts)

(You can use your lecture notes and the readings provided as well as any other primary source. Make sure you reference your answers.)

1. Graph the endotelial response (i.e. FMD) to exercise. (5 pts)
2. Response to exercise
   1. How did this single exercise session affect endothelial function? (5pts)
   2. Through what mechanism could exercise work? (5 pts)
3. Compare the baseline artery diameters for Men and Women. Explain why the diameters are different. (5 pts)
4. What are the different functions of the endothelium? (5 pts)
5. Why is endothelial function a good independent measure of risk for cardiovascular disease? (5 pts)
6. Explain in detail (use diagrams if you need to) the physiological mechanisms (all the steps) that produce the response of flow mediated dilation. (10 pts)
7. What disease populations have an impaired endothelial function? (5 pts)
8. How does exercise training affect endothelial function in the populations you listed in question #6? (5 pts) (You may have to do a literature search of your own using Google Scholar).
9. FMD and diet.
   1. How does diet affect endothelial function? (5 pts)
   2. Through what mechanism does diet affect FMD? (5 pts)
10. Aging and endothelial function:
    1. How does aging affect endothelial function? (5 pts)
    2. Does exercise have a role in endothelial function and aging? If so what can exercise do? (5 pts)
11. What interventions can improve endothelial function in disease populations? (5 pts)
12. List other ways can endothelial function be measured? (5 pts)
13. Describe how each of the other methods to measure endothelial function (listed in question 12) works? (Doctoral Students Only or Extra Credit for Master's students; 10 pts)

1. Maiorana, A., F. O'Droscoll, R. Taylor, and D. Green. Exercise and the Nitric Oxide Vasodilator System. Sports Med. 33:1013-1035, 2003.
2. Rywik, T., M. Blackman, A. Yataco, P. Vaitkevicius, R. Zink, E. Cottrell, J. Wright, L. Katzel, and J. Fleg. Enhanced endothelial vasoreactivity in endurance trained older men. J Appl Physiology. 87:2136-2142, 1999.
3. Stewart, K., J. Sung, H. Silber, J. Fleg, M. Kelemen, K. Turner, A. Bacher, D. Dobrosielski, J. R. DeRegis, E. Shapiro, and P. Ouyang. Exaggerated exercise blood pressure is related to impaired endothelial vasodilator function. AJH. 17:314-320, 2004.
4. Uehata, A., E. Lieberman, M. Gerhard, T. Anderson, P. Ganz, J. Polak, M. Creager, and A. Yeung. Noninvasive assessment of endothelium-dependent flow-mediated dilation of the brachial artery. Vascular Medicine. 2:87-92, 1997.
5. Vogel, R.A, M.C. Corretti, and G.D. Plotnick. Effects of a single-high fat meal on endothelial function in healthy subjects, American Journal of Cardiology 79:350-345, 1997.
6. Seals, D.R., Habitual exercise and the age-associated delcine in large artery compliance. Exercise and Sport Science Reviews, 31:68-72, 2003.
7. Faulx, M.D., A.T. Wright, and B.D. Hoit. Detection of endothelial dysfunction with brachial artery ultrasound scanning. American Heart Journal 145:943-951, 2003.
8. Verma, S., M.R. Buchman, and T.J. Anderson. Endothelial function testing as a biomarker of vascular disease, Circulation 108:2054-2059, 2003.