Changes in intracellular calcium and magnesium concentrations seem to be involved in the pathogenesis of preeclampsia, whereas the role of cell membranes has not been studied in detail yet. To investigate the changes in calcium and magnesium metabolism in normal pregnancy and preeclampsia, plasma, intracellular, and membrane calcium and magnesium concentrations were determined in a clinical study. Twenty-five control, 18 untreated healthy pregnant, and 16 nulliparas preeclamptic women were investigated. Plasma, cellular, and membrane (erythrocytes) calcium and magnesium contents were measured by atomic absorption spectroscopy. Plasma and intracellular magnesium concentrations were significantly lower in the healthy pregnant group and the preeclamptic group as compared to controls (P < .01). In erythrocyte membranes magnesium content was found significantly decreased in the preeclamptic women as compared to healthy subjects (P < .001). There was a significant decrease in the plasma calcium concentration in the preeclamptic group compared to controls or healthy pregnant women (P < .05). Membranous calcium content was significantly increased in the preeclamptic group versus controls or healthy pregnant women (P < .001) and an inverse correlation with membranous magnesium content was found (r = -0.79,P < .01). Lowered plasma, intracellular, and membrane magnesium concentrations in preeclampsia may contribute to the development in hypertension in pregnancy. In addition, a disturbed calcium homeostasis is observed in preeclampsia.
"Kisters and collaborators  observed a lower content of Mg2+ and a higher content of Ca2+ in membranes of red blood cells from preeclamptic pregnant women, as compared with the red blood cells of uncomplicated pregnant women. These alterations could lead to interactions of these ions with membrane components, resulting in modifications of the lipid microenvironment that interacts with membrane transporters. "
[Show abstract][Hide abstract] ABSTRACT: In the current study the possible relationship between the Ca(2+)/Mg(2+) ratio of human syncytiotrophoblast plasma membranes and their lipid peroxidation and Ca(2+)-ATPase activity was determined. Syncytiotrophoblast plasma membranes of placental explants cultured under hypoxia increased their lipid peroxidation and Ca(2+) content, diminished their Ca(2+)-ATPase activity, and kept their Mg(2+) content unchanged. Membranes preincubated with different concentrations of Ca(2+) increased their Ca(2+) content without changes in their Mg(2+) content. There is a direct relationship between Ca(2+) content and lipid peroxidation of the membranes, as well as an inverse relationship between their Ca(2+) content and Ca(2+)-ATPase activity. On the contrary, preincubation of membranes with different concentrations of Mg(2+) showed a higher Mg(2+) content without changing their lipid peroxidation and Ca(2+)-ATPase activity. Explants cultured under hypoxia in the presence of 4 mM MgSO4 showed similar values of lipid peroxidation and Ca(2+)-ATPase activity of their membranes compared to those of explants cultured under normoxia. Increased Ca(2+) content of the membranes by interacting with negatively charged phospholipids could result in destabilizing effects of the membrane structure, exposing hydrocarbon chains of fatty acids to the action of free radicals. Mg(2+) might exert a stabilizing effect of the membranes, avoiding their exposure to free radicals.
BioMed Research International 08/2014; 2014:597357. DOI:10.1155/2014/597357 · 3.17 Impact Factor
"Intervention with magnesium-rich water lowered blood pressure in a risk group . Some studies have reported significantly lower amounts of plasma magnesium in pregnant women with gestational hypertension  . "
[Show abstract][Hide abstract] ABSTRACT: Objectives
High blood pressure during the last part of pregnancy is a risk indicator of pre-eclampsia and eclampsia which augment infant and maternal morbidity and mortality. Magnesium deficiency has been related to the risk of hypertension. A study was performed to assess the relation between pregnancy induced hypertension, excretion of urinary magnesium and expression of magnesium sensitive genes (MgSG).
A cohort of healthy, nulliparous women with singleton pregnancies was recruited. Blood pressure was recorded throughout pregnancy. Urinary magnesium excretion and expression of MgSGs in leukocytes were determined.
The expression of the gene TRPM6 was higher among pregnant women compared to non-pregnant controls at week 12. All other genes had lower expressions in pregnant women. At week 37 the expressions of all genes were lower than at week 12. The expressions of SLC41A1, SLC41A3, and TRPM7 were related to the systolic and diastolic blood pressures. Furthermore, the expression of TRPM6 was related to the urinary excretion of magnesium and the change in diastolic blood pressure weeks 12–37 was inversely related to the change in magnesium excretion.
Systolic and diastolic blood pressure and the excretion of magnesium during pregnancy were related to the expression of different MgSGs. The results suggest that magnesium is involved in the regulation of blood pressure during pregnancy.
"Although plasma Ca 2+ levels may be low in PE, the erythrocytes [Ca 2+ ] i and membrane Ca 2+ content are increased, suggesting altered membrane ion transport (Table 2). The highest BP measurements were recorded in PE women with extremely high erythrocytes [Ca 2+ ] i (Kisters et al.,2000). The increased erythrocytes [Ca 2+ ] i in PE may be caused by an increase in PTH (Sowers et al., 1989; Kosch et al., 2000). "
[Show abstract][Hide abstract] ABSTRACT: Normal pregnancy is associated with significant hemodynamic changes in the cardiovascular system in order to meet the metabolic demands of mother and fetus. These changes include increased cardiac output, decreased vascular resistance, and vascular remodeling in the uterine and systemic circulation. Preeclampsia (PE) is a major complication of pregnancy characterized by proteinuria and hypertension. Several risk factors have been implicated in the pathogenesis of PE including genetic and dietary factors. Ca2+ is an essential dietary element and an important regulator of many cellular processes including vascular function. The importance of adequate dietary Ca2+ intake during pregnancy is supported by many studies. Pregnancy-associated changes in Ca2+ metabolism and plasma Ca2+ have been observed. During pregnancy, changes in intracellular free Ca2+ concentration ([Ca2+](i)) have been described in red blood cells, platelets and immune cells. Also, during pregnancy, an increase in [Ca2+](i) in endothelial cells (EC) stimulates the production of vasodilator substances such as nitric oxide and prostacyclin. Normal pregnancy is also associated with decreased vascular smooth muscle (VSM) [Ca2+](i) and possibly the Ca2+-sensitization pathways of VSM contraction including protein kinase C, Rho-kinase, and mitogen-activated protein kinase. Ca2+-dependent matrix metalloproteinases could also promote extracellular matrix degradation and vascular remodeling during pregnancy. Disruption in the balance between dietary, plasma and vascular cell Ca2+ may be responsible for some of the manifestation of PE including procoagulation, decreased vasodilation, and increased vasoconstriction and vascular resistance. The potential benefits of Ca2+ supplements during pregnancy, and the use of modulators of vascular Ca2+ to reduce the manifestations of PE in susceptible women remain an important area for experimental and clinical research.
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