Articles
American Journal of Hypertension 2009; 22 12, 1263–1269. doi:10.1038/ajh.2009.182
Oral Calcium Supplementation Ambulatory Blood Pressure and Relation to Changes in Intracellular Ions and Sodium–Hydrogen Exchange
Maria I. Pikilidou1, Christina D. Befani2, Pantelis A. Sarafidis1, Peter M. Nilsson3, George G. Koliakos2, Ioannis M. Tziolas1, Kiriakos A. Kazakos1, John G. Yovos1 and Anastasios N. Lasaridis1
- 11st Department of Internal Medicine, Aristotle University of Thessaloniki, AHEPA Hospital, Thessaloniki, Greece
- 2Department of Biological Chemistry, Medical School, Aristotle University, Thessaloniki, Greece
- 3Department of Clinical Sciences, Malmö University Hospital, Lund University, Malmö, Sweden
Correspondence: Maria I. Pikilidou, (m_pikilidou@yahoo.com)
Received 28 March 2009; First Decision 7 June 2009; Accepted 24 August 2009; Published online 24 September 2009.
Abstract
Background
Calcium (Ca2+) supplementation has been shown paradoxically to reduce intracellular Ca2+ and induce vascular relaxation. The aim of the study was to assess 24-h blood pressure (BP) change after Ca2+ supplementation and to investigate its relation to changes in intracellular ions and the activity of the first isoform of sodium–hydrogen exchange (NHE-1) in subjects with hypertension and type 2 diabetes.
Methods
This parallel, randomized controlled, single-blinded trial, consisted of 31 patients with type 2 diabetes, and hypertension who were allocated to receive 1,500 mg of Ca2+ per day (n = 15) or no treatment (n = 16) for 8 weeks.
Results
In the Ca2+ group a decrease of 1.7 
2.7 mm Hg (mean SE) P = 0.52 for mean 24-h systolic BP (SBP) and 2.1 1.5 mm Hg, P = 0.19 for mean 24-h diastolic BP (DBP) was recorded. Whereas in the control group an increase of 1.4 2.7 mm Hg, P = 0.59 for mean 24-h SBP and 1.2 2.8 mm Hg, P = 0.83 for mean 24-h DBP was observed. Intraplatelet Ca2+ decreased whereas intraplatelet magnesium (Mg2+) and erythrocyte K+ increased in the intervention group. Change in mean 24-h SBP in the pooled group correlated with both change in intraplatelet Ca2+ (r = 0.49, P < 0.05) and NHE-1 activity (r = 0.6, P < 0.001). The contribution of intraplatelet Ca2+ was attenuated when both parameters were entered in a multivariate regression model.
Conclusions
The present study shows a weak, statistically nonsignificant trend towards association of Ca2+ supplementation on 24-h BP in hypertensive subjects with type 2 diabetes. However, our results indicated an interrelation of [Ca2+]i levels and NHE-1 activity on BP in patients with hypertension and type 2 diabetes.
American Journal of Hypertension 2009; doi:10.1038/ajh.2009.182
