The sensitivity of human blood platelets to the aggregating agent ADP during different dietary sodium intakes in healthy men

Abstract

We have investigated the effect of varying sodium intake on the renin-angiotensin system, ADP-induced platelet aggregation in vitro, and blood 5-HT concentrations in 9 male volunteers. Systolic blood pressure was slightly reduced during a low sodium diet, whereas the diastolic pressure remained unchanged. Plasma renin activity and aldosterone concentration both fell significantly when sodium intake was increased; plasma angiotensin II concentration also fell, but not significantly. There was a significant fall in haematocrit after an increased sodium intake, but there was no change in the whole-blood platelet count after correcting for this. There were no significant changes in either total (i.e. PRP) or platelet 5-HT concentrations. The extent of platelet aggregation induced by 5 and 20 mumol.l-1 of ADP increased significantly when dietary sodium intake was increased. When compared with low or normal sodium intakes, lower concentrations of ADP were required to produce 50% of maximum aggregation after a high sodium intake. The 5-HT2 receptor antagonist ketanserin (1 mumol.l-1 in vitro) reduced the extent of aggregation induced by 5 mumol.l-1 ADP after the volunteers had taken a high sodium diet, whereas the angiotensin II receptor antagonist saralasin (1 nmol.l-1) increased the rate of aggregation after the low sodium diet. Thus, during a high sodium intake, human platelets become more sensitive to the aggregating agent ADP. It is possible that this effect is mediated via platelet 5-HT2 receptors, since ketanserin abolished the increase in salt-induced aggregation seen with 5 mumol.l-1 ADP.

Effect of dose and duration of reduction in dietary sodium on blood pressure levels: systematic review and meta-analysis of randomised trials

“…After screening titles and abstracts, we selected 462 publications for full text review, of which 329 were excluded for the reasons summarised in figure 1. One hundred and thirty three studies27282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119…”

The Science of Salt: A Regularly Updated Systematic Review of Salt and Health Outcomes (June and July 2015)

“…We also noted possible discrepancies with respect to the accuracy of data extraction. For example, the included study by Gow and colleagues reported a mean systolic BP of 120 mm Hg in the normal sodium diet group, and Gradual and colleagues reports these data as missing. Table S4 contains errors in sodium intake and BP values for Burnier and colleagues and Heer and colleagues A detailed analysis of all the extracted data has not yet been conducted.…”

Harmful effects of dietary salt in addition to hypertension

“…52 Similarly in normal women a change in salt intake from 10 to 200 mmol/day was associated with a significant increase in platelet aggregation. 53 In two groups of men with and without a family history of hypertension a high salt intake increased the blood pressure of those with a family history but platelet aggregation increased in both groups, though it rose more in those with a family history.…”