Diabetes Care, Vol 15, Issue 7 835-841, Copyright © 1992 by American Diabetes Association
Intracellular free magnesium deficiency plays a key role in increased platelet reactivity in type II diabetes mellitus
JL Nadler, S Malayan, H Luong, S Shaw, RD Natarajan and RK Rude
Department of Diabetes, Endocrinology and Metabolism, City of Hope National Medical Center, Duarte, California 91010.
OBJECTIVE--Mg deficiency may be an important factor leading to
cardiovascular disease. Diabetic subjects show an increase in platelet
reactivity that can enhance the risks of vascular disease. In addition,
diabetic patients have been reported to be at risk of developing
extracellular Mg deficiency. However, the intracellular free Mg
concentration and its role in the enhanced platelet reactivity in diabetes
is not known. RESEARCH DESIGN AND METHODS--We evaluated the intracellular
erythrocyte (RBC) Mg2+ concentration in 20 non-insulin-dependent (type II)
diabetics. In addition, the effects of intravenous 3-h drip or 8 wk of oral
Mg supplementation on intracellular RBC Mg2+ levels and platelet reactivity
was studied. To more clearly evaluate the direct role of Mg in these
effects, we induced isolated Mg deficiency in 16 nondiabetic control
subjects with an Mg-free liquid diet for 3 wk. RESULTS--The intracellular
RBC Mg2+ concentration of diabetic patients was significantly reduced
compared with values in nondiabetic control subjects (166 +/- 7 vs. 204 +/-
7 microM, P less than 0.01). Serum Mg levels were also reduced in the
diabetic patients compared with the control subjects (1.59 +/- 0.04 vs. 1.9
+/- 0.1 mEq/L, P less than 0.05). Oral Mg supplementation for 8 wk (400
mg/day) restored RBC Mg2+ concentration to normal without significantly
changing serum Mg concentration. Both intravenous and oral Mg
supplementation markedly reduced platelet reactivity in response to the
thromboxane A2 analog, U46619. The Mg-free diet resulted in a significant
reduction in RBC Mg2+ concentration and markedly enhanced the sensitivity
of platelet aggregation to U46619 and ADP. CONCLUSIONS--These results
suggest that type II diabetic patients have intracellular Mg2+ deficiency
and that Mg deficiency may be a key factor in leading to enhanced platelet
reactivity in type II diabetes. Therefore, Mg supplementation may provide a
new therapeutic approach to reducing vascular disease in patients with
diabetes.