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Abstract: TH-PO450

Age, Tissue Sodium, and Blood Pressure Associations in Healthy, Hypertensive, and Hemodialysis Subjects

Session Information

Category: Hypertension and CVD

  • 1401 Hypertension and CVD: Epidemiology, Risk Factors, and Prevention

Authors

  • Perez, Luis M., University of Illinois, Urbana, Illinois, United States
  • Fang, Hsin-Yu, University of Illinois, Urbana, Illinois, United States
  • Burrows, Brett, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
  • Derk, Gwendolyn, University of Illinois, Urbana, Illinois, United States
  • Larsen, Ryan J., University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
  • Wilund, Ken, University of Illinois, Urbana, Illinois, United States

Group or Team Name

  • Renal and Cardiovascular Research Laboratory
Background

Sodium magnetic resonance imaging (23Na MRI) can non-invasively quantify sodium (Na) concentrations in tissues such as the skin and muscle. However, previous tissue Na studies in healthy subjects and hemodialysis patients reported only one lower leg concentration. We used 23Na MRI to quantify tissue Na in the anterior (AT) and posterior (PT) muscle regions of the leg in healthy, hypertensive (HTN), and HD subjects. We also examined group differences in tissue Na concentrations and the association of tissue Na to age and blood pressure (BP).

Methods

We recruited 22 subjects (45+18 years, 26.0+3.7 kg/m2, 50% male, 64% white, 50% HTN, 27% HD) from the University of Illinois and a dialysis clinic in central Illinois. 23Na MRI was performed on a Siemens TIM Trio/Prisma II 3T system (birdcage head coil). We conducted 23Na MRI region of interest (ROI) analysis in a double-randomized and blinded manner for tissue Na concentrations. We also collected height, weight, and standardized BP.

Results

Across groups, Na concentration was significantly different (p<0.05) and lower in AT compared to PT (AT 18.6+5.1 mM, PT 26.0+4.9 mM; p< 0.05). PT Na was correlated both with age (R=0.64, p<0.01) and SBP (R=0.57, p<0.01). AT Na was also correlated with age (R=0.68, p<0.01), SBP (R=0.70, p<0.01), and with PT Na (R=0.62, p<0.01). Regression analysis demonstrated a significant relation between both age and SBP with both AT Na and PT Na (Table 1).

Conclusion

Na concentration in the calf differs depending on the site of quantification, with AT having a lower concentration than PT. This was a consistent finding across subject groups, despite differing Na concentrations by group. AT and PT are correlated with each other as well as age and SBP. Lower leg Na concentrations could differ due to muscle fiber type differences or because the AT region is smaller muscle group, thus more difficult to quantify than the PT region.

Age and BP Regression by Tissue Sodium
 Model A: AT Tissue Na, mMModel B: PT Tissue Na, mM
 BetaP-valueAdj. R^2BetaP-valueAdj. R^2
Model 1 
Age, years0.18<0.010.430.16<0.010.40
Model 2 
BP, mmHg0.16<0.010.460.13<0.010.29