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Insulin sensitivity increase after calcium supplementation and change in intraplatelet calcium and sodium–hydrogen exchange in hypertensive patients with Type 2 diabetes 1
Author(s) -
Pikilidou M. I.,
Lasaridis A. N.,
Sarafidis P. A.,
Befani C. D.,
Koliakos G. G.,
Tziolas I. M.,
Kazakos K. A.,
Yovos J. G.,
Nilsson P. M.
Publication year - 2009
Publication title -
diabetic medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.474
H-Index - 145
eISSN - 1464-5491
pISSN - 0742-3071
DOI - 10.1111/j.1464-5491.2009.02673.x
Subject(s) - medicine , endocrinology , insulin , type 2 diabetes , calcium , diabetes mellitus , sodium , sodium–hydrogen antiporter , chemistry , organic chemistry
Aims/hypothesis To investigate the effect of oral calcium (Ca 2+ ) supplementation on insulin sensitivity measured by the euglycaemic hyperinsulinaemic clamp, intraplatelet cationic concentration of Ca 2+ ([Ca 2+ ] i ) and the transmembrane sodium–hydrogen exchanger (NHE) activity in erythrocytes in subjects with Type 2 diabetes and hypertension. Patients and methods In this parallel randomized controlled single‐blinded trial, 31 patients were allocated to receive either 1500 mg of Ca 2+ orally, daily ( n = 15) or no treatment ( n = 16) for 8 weeks. At baseline and at the end of the 8‐week period insulin sensitivity, [Ca 2+ ] i and the first isoform of NHE (NHE‐1) activity were measured. Results At the end of the study, subjects who received Ca 2+ supplementation showed higher insulin sensitivity (Δ M ‐value 0.32 ± 0.5 mmol/min P < 0.05) and lower [Ca 2+ ] i (125.0 ± 24.7 to 80.4 ± 10.6 nmol/l, P < 0.05, mean ± sem ) and NHE‐1 activity (79.5 ± 10.0 to 52.1 ± 6.4 mmol Na/l red cell/h, P < 0.05). None of the above parameters were changed in the control group. Simple regression analysis demonstrated the change in [Ca 2+ ] i significantly determined insulin sensitivity change (β = −0.36, P < 0.05). Conclusions/interpretation Oral Ca 2+ supplementation improves insulin sensitivity in patients with Type 2 diabetes and hypertension. These changes are likely to be mediated by changes in intracellular ionic Ca 2+ . NHE‐1 activity was also reduced after Ca 2+ supplementation but its role in insulin sensitivity requires further investigation.