Platelet sodium pump and sodium potassium cotransport activity in nonpregnant, normotensive, and hypertensive pregnant women

Exploring the Spectrum of Electrolyte Imbalances in Preeclampsia: Mechanisms, Implications, and Clinical Insights

Preeclampsia, a complex and perplexing disorder unique to pregnancy, is widely recognized as primarily originating from placental dysfunction and can only be resolved by the delivery of the fetus in severe cases. Preeclampsia is a prevalent medical issue during pregnancy and is associated with elevated rates of maternal and infant mortality and morbidity. The exact cause of preeclampsia remains uncertain, although multiple factors have been implicated in its development based on current knowledge. Preeclampsia is characterized by maternal endothelial dysfunction due to the presence of fetal-derived circulatory substances from the placenta. The condition is associated with various risk factors, including maternal comorbidities such as chronic renal disease, hypertension (HTN), and obesity. Additionally, a family history of preeclampsia, nulliparity, multiple gestations, previous instances of preeclampsia, or intrauterine fetal growth restriction (IUGR) are considered risk factors. Electrolytes, including sodium, potassium, and chloride, play a critical role in the function of vascular smooth muscles and may potentially contribute to the pathophysiology of hypertension. In this review, we have summarized the literature on electrolytes in preeclampsia by conducting an extensive systematic search of databases such as PubMed, Excerpta Medica database (EMBASE), and Medical Literature Analysis and Retrieval System Online (MEDLINE).

A novel assay of cell rubidium uptake using graphite furnace atomic absorption: Application to rats on a magnesium-deficient diet

The [Na,K]ATPase or sodium pump (SP) is a ubiquitous membrane cation transport system. Because of its potential participation in the pathophysiology of essential hypertension and cataract formation, the SP is under active investigation to detail its function and control. In this paper, we describe a novel, nonradioactive method of measuring SP ion transport activity in intact red blood cells (RBCs) using graphite furnace atomic absorption measurement of rubidium ion (Rb) uptake. This method provided sensitivity comparable to radioactive techniques, as assessed by experiments with human red blood cells (RBC) and ouabain, a known SP inhibitor, but this analytical approach eliminates the use of radioisotopes common to other Rb uptake assay methods. As a demonstration of its broader utility, the assay was used to assess the effects of dietary magnesium intake on SP-mediated ion transport in the RBCs of diet-controlled rats. Rats on 7 weeks of a magnesium-deficient (MgD) diet showed significant reductions in serum magnesium concentration, although levels remained in the lower region of the reference interval for healthy, magnesium replete animals. Red cell Rb uptake was significantly reduced in cells from the magnesium-restricted animals, demonstrating the sensitivity of Rb uptake to reduced magnesium intake, despite serum levels that fell within the reported normal range, and the utility of this Rb uptake assay in measuring physiological changes in SP function.

Platelet activation in the hypertensive disorders of pregnancy

The hypertensive disorders of pregnancy, including gestational hypertension, pre-eclampsia and eclampsia, continue to be an important cause of maternal morbidity and mortality. Abnormal placentation is considered to be the main instigating factor, which then leads to widespread maternal endothelial activation and dysfunction. This endothelial perturbation leads to the release of many substances into the circulation, many of which result in platelet activation. For example, there is an imbalance between the levels of prostacyclin (a vasodilator and platelet inhibitor) and thromboxane (a platelet activator and vasoconstrictor), which then results in the maintenance of high blood pressure and complications. It is also likely that platelets play an important part in the pathogenesis of hypertension in pregnancy. The use of antiplatelet drugs has been shown to be effective in reducing the incidence of gestational hypertension in women at high risk and in preventing the complications associated with it. In addition, some antihypertensive agents are effective in reversing platelet activation in essential hypertension and, therefore, their use in pregnancy-induced hypertension may be beneficial in more ways than simply blood pressure reduction.