Sodium pump inhibitors in blood pressure regulation and in profibrotic signaling in salt sensitive hypertension and aging

非洲PREDICT研究（关于心血管疾病和高血压早期检测和识别的非洲前瞻性研究）是一项正在南非西北大学波切夫斯特鲁姆进行的研究（Strauss et al，2017）。我们纳入了331名来自该研究（20-30岁）的明显健康的参与者（42.9%黑人，43.8%男性），他们习惯性饮食。值得注意的是，参与者每天消耗相对较高的氯化钠量：女性平均6.5 g/24 hr，男性平均8.5 g/24 hr，黑人和白色都是如此。测定24小时收缩压（SBP）、中心收缩压（SBP）、24小时尿Na+、尿MBG。我们发现MBG、Na+或MBG/Na+没有种族差异。所有组的MBG排泄与Na+排泄呈正相关，白色男性和黑人女性的MBG排泄与SBP呈正相关（p<0.011）。在黑人女性中，在单变量和多变量调整回归模型中，仅SBP与MBG/Na+呈正相关：中心SBP（R平方=0.26; β =0.28; p=0.039），24小时SBP（R平方=0.46; β =0.30; p=0.011）、日间（R平方=0.38; β =0.28; p=0.023）和夜间SBP（R平方=0.38; β =0.33; p=0.009）。相比之下，在白色女性中，MBG/Na+与夜间SBP呈明显的负相关（r= -0.20; p=0.038），但在多次校正后失去了显著性（R平方=0.36; β = -0.13; p=0.12）。我们发现黑人女性SBP与MBG/Na+独立正相关。该数据支持MBG介导的Na+排泄减少可导致不良血流动力学的概念。 总之，在年轻黑人女性中，MBG/Na+排泄比与cSBP、24小时SBP和每搏输出量增加相关，这可能反映了钠处理异常导致的心血管风险增加。相反，年轻白色女性中MBG/Na+和夜间SBP之间的负相关性支持MBG在年轻健康人群中预期的利钠利尿作用的概念。

African PREDICT study (African Prospective study on the Early Detection and Identification of Cardiovascular Disease and Hypertension) is an ongoing study held at the North-West University, Potchefstroom, South Africa (Strauss et al, 2017). We included 331 apparently healthy participants from that study (20-30 years) (42.9% black, 43.8% men) on a habitual diet. Notably, that the participants consumed relatively high sodium chloride amount on a daily basis: in average 6.5 g/24hr for women and 8.5 g/24hr for men, both black and white. We obtained 24hr and central SBP, and 24hr urinary Na+ and MBG levels. We found no ethnic differences in MBG, Na+ or MBG/Na+. MBG excretion correlated positively with Na+ excretion in all groups and to SBP in white men and black women (p<0.011). In black women only SBP related positively to MBG/Na+ in single and multi-variable adjusted regression models: central SBP (R-squared=0.26; beta=0.28; p=0.039), 24hr SBP (R-squared=0.46; beta=0.30; p=0.011), daytime (R-squared=0.38; beta=0.28; p=0.023) and nighttime SBP (R-squared=0.38; beta=0.33; p=0.009). In contrast, inverse associations of MBG/Na+ with nighttime SBP were evident in white women (r= -0.20; p=0.038) but lost significance after multiple adjustments (R-squared=0.36; beta= -0.13; p=0.12). We found independent positive associations of SBP with MBG/Na+ in black women. This data supports the concept that reduced MBG-mediated Na+ excretion can contribute to adverse hemodynamics. In conclusion, in young black women the MBG/Na+ excretion ratio associated with an increase in cSBP, 24hr SBP and stroke volume which might reflect an increased cardiovascular risk due to abnormal sodium handling. Conversely, the inverse correlation between MBG/Na+ and nighttime SBP in young white women supports the concept of the expected natriuretic effect of MBG in a young healthy population.