Braxton A. Linder1, Matthew C. Babcock2, Joseph C. Watso3, Austin T. Robinson1. 1Auburn University, Auburn, AL. 2University of Colorado Anschutz Medical Campus, Aurora, CO. 3Florida State University, Tallahassee, FL.

Background: Americans overconsume dietary salt, which is a major risk factor for hypertension and cardiovascular disease. We have demonstrated that short-term high salt (HS) increases blood pressure reactivity (BPR), which is prognostic of incident hypertension. Additionally, HS increases the inflammatory marker monocyte chemoattractant protein-1 (MCP-1), which is associated with increased resting blood pressure (BP) in patient populations. However, it is unclear whether MCP-1 is associated with BPR in healthy young adults. Therefore, the purpose of this study was to examine the relation between resting MCP-1 and BPR during exercise in healthy young adults after 10 days of HS. Methods: We used a randomized, crossover, double-blinded design. 20 young adults (12M/8F, 24 ± 4 yrs, BMI = 23.0 ± 0.6 kg/m2, BP = 111 ± 10/64 ± 8 mmHg) consumed HS (3.9 g sodium) or placebo (PLA; dextrose) capsules for 10 days separated by ≥ two weeks. On day 10 of each intervention, we collected a blood sample and participants completed 50 minutes of 60% VO2max cycling. We used finger photoplethysmography (Finapres Finometer Pro) to assess beat-to-beat BP. We calculated BPR as the difference in average BP from rest compared to average BP during exercise. We used ELISA (R&D Systems) to assess plasma MCP-1 concentrations. We compared MCP-1 concentrations and BPR differences between HS and PLA using a Student’s t or Wilcoxon test. We assessed relations between resting MCP-1 and resting BP and exercising BPR using Pearson’s correlations (r; normally distributed data) and Spearman’s rank correlation (ρ; non-normally distributed data). Significance was set a priori to p ≤ 0.05. Results: There were no differences in resting BP between HS and PLA (ps > 0.831). MCP-1 (PLA; 72.4 ± 12.5, HS; 78.1 ± 14.7, p = 0.010) and systolic BPR (PLA; 30.0 ± 16.3, HS; 38.3 ± 19.3, p= 0.33) were significantly higher after HS versus PLA. However, changes in MCP-1 and systolic BPR were not correlated (r = 0.05, p = 0.758). While MCP-1 was not correlated with BPR within conditions, irrespective of condition, MCP-1 was correlated with resting systolic and mean BP (ps < 0.05). Conclusion: MCP-1 and BP reactivity are increased after 10 days of HS consumption in healthy young adults. There were no correlations between high salt-induced changes in MCP-1 and BPR, however, MCP-1 did correlate with resting systolic and mean BP.

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