Magnesium deficiency and metabolic syndrome: stress and inflammation may reflect calcium activation.

Magnesium (Mg) intake is inadequate in the western diet and metabolic syndrome is highly prevalent in populations around the world. Epidemiological studies suggest that high Mg intake may reduce the risk but the possibility of confounding factors exists, given the strong association between Mg and other beneficial nutriments (vegetables, fibers, cereals). The concept that metabolic syndrome is an inflammatory condition may explain the role of Mg.

Phagocyte priming by low magnesium status: input to the enhanced inflammatory and oxidative stress responses.

Epidemiological and experimental studies underline the role of magnesium in inflammation. Several data indicate an enhanced response of phagocytes (granulocytes, macrophages) derived from magnesium-deficient animals or cultured under low magnesium conditions to the inflammatory mediators' stimulation. On the contrary, it was pointed out that high extracellular Mg2+ concentration might partially attenuate the activation of phagocyte leukocytes.

High-magnesium concentration and cytokine production in human whole blood model.

The potential influence of magnesium (Mg) on inflammatory responses was assessed using an ex vivo model--human whole blood incubated with and without lipopolysaccharide (LPS). Addition of LPS leads to higher levels of cytokines including TNF-alpha and IL-6. No significant effect of Mg was observed following LPS stimulation whereas high concentration of Mg inhibited the baseline level (without LPS) of TNF-alpha and IL-6 production.

Inflammation interferes with the assessment of vitamin A status in magnesium deficiency.

Hyporetinemia is observed in several pathological conditions including a primary deficiency of vitamin A and has also been reported to accompany inflammatory diseases. Experimental magnesium (Mg) deficiency in rodents is accompanied by an inflammatory syndrome. The present study was designed to determine whether the acute phase response in Mg-deficient rats can modify vitamin A status.

Dietary inulin in mice stimulates Mg2+ absorption and modulates TRPM6 and TRPM7 expression in large intestine and kidney.

Complex fermentable carbohydrates, such as inulin-type fructans have been shown to improve Mg2+ absorption in the hindgut and body stores. The mechanisms for this are not well understood. The newly identified transient receptor potential melastatin 6 and 7 (TRPM6 and TRPM7) channels have been shown to function in active epithelial Mg2+ transport in the apical membrane of epithelial cells, the kidney and intestine and to be regulated by dietary intake.

Vascular function of MGH and MGL mice, two strains which differ by a genetic variation of magnesium metabolism.

Mg deficiency is considered as a risk factor of cardiovascular disorders like hypertension and atherosclerosis. MGH and MGL mice, selected for high and low Mg status, are animal models which present variations of Mg metabolism of genetic origin. The cardiovascular functions of these mice have never been studied.

Lipid metabolism and antioxidant status in sucrose vs. potato-fed rats.

Objective: Consumption of high levels of simple carbohydrates is associated with several metabolic disorders in humans and in laboratory animals, including symptoms of an early stage of metabolic syndrome (syndrome X). This disorder has several cardiovascular risk factors, such as hypertriglyceridemia, and is associated with an increase in oxidative stress. In contrast to sucrose, potato, a source of complex carbohydrates and antioxidant micronutrients, was thought to improve lipid metabolism and antioxidant protection.

Relationship between low magnesium status and TRPM6 expression in the kidney and large intestine.

The body maintains Mg(2+) homeostasis by renal and intestinal (re)absorption. However, the molecular mechanisms that mediate transepithelial Mg(2+) transport are largely unknown. Transient receptor potential melastatin 6 (TRPM6) was recently identified and shown to function in active epithelial Mg(2+) transport in intestine and kidney.

Inulin supplementation prevents high fructose diet-induced hypertension in rats.

Background & Aims: The aim of this experiment was to evaluate the potential beneficial effect of supplementation with different inulin-type fructan fractions against common features of the metabolic syndrome in a rat model of this syndrome (fructose-fed rat).

Methods: Forty Wistar rats were randomly divided into five groups and the animals received for 4 weeks either a semi-purified starch or fructose-based diet, or diets in which fructose was partially substituted with various fructans: 10 g/100 g of long-chain inulin or oligofructose, or an oligofructose-enriched inulin. After this period, blood pressure was measured and samples of blood and tissues were collected for selected biochemical analyses.

The effect of aging on intestinal absorption and status of calcium, magnesium, zinc, and copper in rats: a stable isotope study.

Many investigators have reported changes in mineral status with age but conflicting observations were done concerning mineral absorption. This study was conducted to clarify the effect of aging on intestinal absorption and status of minerals, using a stable isotope approach. To do so, 40 rats of different ages: 9, 22, 44, and 88 weeks were fed with a semi-purified diet for a total of 30 days.

Magnesium and the inflammatory response: potential physiopathological implications.

The purpose of this review is to summarize experimental findings showing that magnesium modulates cellular events involved in inflammation. Experimental magnesium deficiency in the rat induces after a few days a clinical inflammatory syndrome characterized by leukocyte and macrophage activation, release of inflammatory cytokines and acute phase proteins, excessive production of free radicals. Increase in extracellular magnesium concentration, decreases inflammatory response while reduction in the extracellular magnesium results in cell activation.

In vivo antioxidant activity of procyanidin-rich extracts from grape seed and pine (Pinus maritima) bark in rats.

Background: In vitro evidence exists for the potential antioxidant benefits of procyanidin-rich extracts, but in vivo studies are scarce. We have evaluated the effects of selected procyanidin-rich extracts on oxidative stress in rats in condition of prolonged consumption of these compounds and also after single administration i.e.

Dietary inulin intake and age can significantly affect absorption of the faecal marker dysprosium in rats.

It is believed that rare earth elements are not absorbed, and thus they are generally used in some mineral absorption studies as a faecal marker. The aim of the present study was to determine the effect of inulin intake and age on dysprosium (Dy) absorption in rats. Eighty male Wistar rats of four different ages (2, 5, 10 and 20 months) were randomised into either a control group or a group receiving 3.

Dietary inulin intake and age can affect intestinal absorption of zinc and copper in rats.

Nondigestible inulin-type fructan intake can stimulate intestinal mineral absorption in both humans and animals. However, this stimulatory effect may depend on experimental conditions such as the duration of the experience, mineral levels in the diet, and the animal's physiological status. The aim of this study was to determine the effect of inulin intake on Zn and Cu absorption in rats at different ages.

Dietary inulin intake and age can significantly affect intestinal absorption of calcium and magnesium in rats: a stable isotope approach.

Background: previous studies have shown that non-digestible inulin-type fructan intake can increase intestinal mineral absorption in both humans and animals. However, this stimulatory effect on intestinal absorption may depend on experimental conditions such as duration of fermentable fiber intake, mineral diet levels and animals' physiological status, in particular their age.

Objectives: the aim of this study was to determine the effect of inulin intake on Ca and Mg absorption in rats at different age stages.

Stable isotopes in studies of intestinal absorption, exchangeable pools and mineral status: the example of magnesium.

Magnesium (Mg) is a biologically essential mineral and Mg deficiency is known to lead to severe biochemical and symptomatic disorders. Radioactive isotopes and, more recently, stable isotopes have been used as research tools to determine intestinal Mg absorption in humans and animals under different nutritional and physiological conditions. Mg isotopes are given orally or orally plus intravenously and analysed in faeces and/or in plasma and urine in order to calculate intestinal Mg absorption and possibly endogenous Mg excretion.

Caffeic acid inhibits oxidative Stress and reduces hypercholesterolemia induced by iron overload in rats.

The effects of caffeic acid, a major phenolic compound of the diet, on oxidative stress and cholesterolemia are studied in rats submitted to oxidative stress by iron overload. Male Wistar rats were fed semi-synthetic diets containing regular (50 mg/kg diet) or high (2000 mg/kg) doses of iron with and without caffeic acid (6460 mg/kg) for 4 weeks. The high doses of iron induced an increase of lipid oxidation in the liver, as measured by thiobarbituric acid-reactive substances (TBARS), and an increase of cholesterolemia.

Evaluation of magnesium fluxes in rat erythrocytes using a stable isotope of magnesium.

The mechanisms that maintain intracellular Mg concentration at physiologic levels are not fully understood. In this work, we described for the first time, a new method using 25Mg stable isotopes, that allows simultaneous determination of Mg2+ efflux and Mg2+ influx in non-loaded cells at physiological levels of extracellular Mg. Erythrocytes from rats were suspended as a 10% suspension in NaCl medium or choline medium.

[Magnesium and inflammation: lessons from animal models].

The purpose of this review is to summarize experimental findings showing that Mg modulates cellular events involved in inflammation. Severe experimental Mg deficiency in the rat induces after a few days a clinical inflammatory syndrome characterized by PMN and macrophage activation, release of inflammatory cytokines and acute phase proteins, excessive production of free radicals. Increasing Mg concentration decreases inflammatory response while reduction in the extracellular Mg results in cell activation.

Influence of short-chain fructo-oligosaccharides (sc-FOS) on absorption of Cu, Zn, and Se in healthy postmenopausal women.

Objective: This study was carried out to evaluate the effect of short-chain fructooligosaccharides (sc-FOS) on the absorption of Cu, Zn, and Se among postmenopausal women who are potential candidates to subclinical trace element deficiencies.

Design: A randomized double blind cross-over study.

Setting: This study was carried out at the Human Nutrition Research Center, Clermont-Ferrand, France.

Magnesium deficiency inhibits primary tumor growth but favors metastasis in mice.

The results of several experimental and epidemiological studies have shown an inverse correlation between Mg status and the risk of some cancers. However, relationship between magnesium and cancer is complex. The aim of our work was to examine the precise effect of Mg deficiency on transplantable mouse tumor growth and metastasis.

Low magnesium promotes endothelial cell dysfunction: implications for atherosclerosis, inflammation and thrombosis.

Because (i). endothelial cells are important players in cardiovascular diseases and (ii). Mg deficiency promotes atherosclerosis, thrombosis and hypertension, we evaluated whether low concentrations of Mg could directly affect endothelial behavior.

High concentrations of magnesium modulate vascular endothelial cell behaviour in vitro.

Magnesium supplementation has been reported to prevent cardiovascular diseases through the decrease of plasma lipids and to improve endothelial function in patients with coronary artery disease. In the present work, we evaluated whether high magnesium concentrations can directly affect the function of cultured endothelial cells, which play a crucial role in maintaining the functional integrity of the vascular wall. We cultured human umbilical vein endothelial cells for various times in media containing different concentration of magnesium (range 2 to 10 mM) and compared them to the corresponding controls (1 mM Mg).