BACKGROUND:Dietary sodium affects fluctuations in blood pressure (BP) and vascular function. Cardiotrophin-1 (CT-1), a stress-induced cytokine that belongs to the interleukin 6 family, is released by cells in response to potentially harmful stresses and plays a pivotal role in congestive heart failure, hypertension and arterial stiffness. In this study, we performed a randomized trial to confirm the effects of altered salt intake on the serum CT-1 levels in humans. METHODS:Forty-four subjects (18-65 years of age) were selected from a rural community in northern China. All subjects initially maintained a baseline period for 3 days, transitioned to a low-salt (LS) diet for 7 days (3.0 g/day of NaCl) and then a high-salt (HS) diet for an additional 7 days (18.0 g/day of NaCl). RESULTS:For the whole group, the serum CT-1 concentrations were significantly increased in the HS period compared to those of the LS period (293.50 ± 137.70 vs. 360.40 ± 162.83 pg/mL, p = 0.040). The serum CT-1 concentrations significantly decreased from the baseline period to the LS diet (419.91 ± 123.50 to 256.49 ± 109.75 pg/mL, p < 0.01) and significantly increased from the LS to HS diet (256.49 ± 109.75 to 414.39 ± 191.21 pg/mL, p < 0.01). These changes were observed in salt-sensitive (SS) individuals but not in salt-resistant (SR) individuals. In addition, a significant positive relationship was observed between the changes in the CT-1 concentrations and systolic BP as well as the changes in the mean arterial pressure from the LS period to the HS period (r = 0.376, p = 0.012; r = 0.311, p = 0.040). The serum CT-1 concentrations were positively correlated with the 24-h urinary sodium-to-potassium (Na/K) excretion ratios during both of the LS and HS diet intervention periods in SS subjects (r = 0.621, p < 0.01), but this correlation was not evident in SR subjects (r = 0.208, p = 0.107). CONCLUSIONS:Our study indicates that variations in dietary salt intake affect the serum CT-1 levels in Chinese adults.
KEYWORDS: Blood pressure, Cardiotrophin-1, Dietary interventions, Salt