A long-term moderate magnesium-deficient diet aggravates cardiovascular risks associated with aging and increases mortality in rats.
OBJECTIVE
The present study aimed to show whether long-term moderate magnesium (Mg)-deficient (150 mg/kg) and Mg-supplemented (3200 mg/kg) diets (versus control diet: 800 mg/kg), modified the occurrence of cardiovascular risk induced by aging in the rat.


METHODS
Cardiovascular and arterial functions were determined by a systemic hemodynamic study and by ex vivo measurements of vasoconstriction and endothelium dependent-vasorelaxation. Arterial wall structure was determined using pressure myograph chamber and histomorphometric methods.


RESULTS
The main changes observed in old rats (96 weeks old) fed a control diet, in comparison to adult rats (16 weeks old) were increased pulse pressure, a loss of aortic endothelium-dependent relaxation, increased aortic wall thickness and a decrease of the aortic wall elastin/collagen ratio. Long-term moderate Mg deficiency progressively increased systolic blood pressure. Intra-arterial pulse pressure was higher in Mg-deficient old rats than in age-matched control rats. Histological examination showed that Mg deficiency increased the age-induced deleterious effects on composition and structure of aorta (media thickness, increased collagen content and reduction in the elastin/collagen ratio), which lead to large artery rigidity. Hypertension and increased pulse pressure may have contributed to the increase in the mortality rate observed in the hypertensive Mg-deficient group. Although the long-term Mg-supplemented diet lowered blood pressure and decreased the mortality rate, it had no significant effect on aortic wall thickening and stiffening.


CONCLUSIONS
It is suggested that a long-term and moderate Mg-deficient diet increases age-induced arterial thickness and stiffness in rats, and thus increases the cardiovascular risks incurred by aging.
Adrian
Marcus
M
EA3921 Metabolic and cellular optimisation, Université de Franche-Comté, UFR Sciences Médicales et Pharmaceutiques, Besançon, France.
Chanut
Evelyne
E
Laurant
Pascal
P
Gaume
Vincent
V
Berthelot
Alain
A
D000109:Acetylcholine / Q000494:pharmacology; D000375:Aging / Q000473:pathology; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology*; D001794:Blood Pressure / Q000187:drug effects; D002318:Cardiovascular Diseases / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D019587:Dietary Supplements; D019332:Endothelin-1 / Q000494:pharmacology; D005526:Food, Formulated; D008274:Magnesium / Q000008:administration & dosage* / Q000097:blood; D008275:Magnesium Deficiency / Q000150:complications / Q000503:physiopathology* / Q000517:prevention & control; D008297:Male; D009599:Nitroprusside / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D009924:Organ Culture Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D012307:Risk Factors; D015996:Survival Rate; D013995:Time; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology; D014666:Vasomotor System / Q000187:drug effects
D019332:Endothelin-1; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009599:Nitroprusside; D008274:Magnesium; D000109:Acetylcholine; D009638:Norepinephrine