Influence of an adecuate zinc intake during fetal and posnatal and adult life on arterial blood pressure and cardiovascular nitric oxide system

ARRANZ C; TOMAT A.; FINELLA S; ELESGARAY R.; VEIRAS L; BALASZCZUK A.; COSTA A.

Buenos Aires

Congreso; World Congress of Cardiology 2008; 2008

Worl Heart Federation, Sociedad Argentina de Cardiología

Nutrient restriction during critical periods of intrauterine and postnatal growth may result in long-term structural and functional effects and increased risk for the development of cardiovascular pathologies. Previously we demonstrated that moderate zinc deficiency during growth induces an increase in arterial blood pressure and an impaired renal function in the adult life. Moreover it is known that nitric oxide synthase (NOS) is one of the zinc requiring enzymes family and its zinc center is considered to play an essential role in the catalytic activity. The aim was to study 1) the effects of moderate zinc deficiency during fetal and early postnatal life on systolic blood pressure (SBP), cardiac and vascular NOS in the adults and, 2) the effects of zinc supplementation in the adult life after the deficiency during growth. Female Wistar rats received from the beginning of pregnancy up to weaning low (L: 8 ppm zinc) or control (C: 30 ppm zinc) zinc diet. After weaning, male offspring of each group of mothers continued with low (Cl and Ll) or control (Cc and Lc) zinc diet during 60 days. At the end of this period, SBP (mmHg), urinary concentration of nitrites and nitrates (NOx, nmol/ml.min.100 g), NOS activity with L-[U14C]-arginine in aorta and cardiac ventricle (pmol/min„ªg tissue) were evaluated in 6 animals of each experimental group. Other 6 animals of Cl and Ll groups continued with a diet containing 60 ppm zinc (Cls and Lls), during 60 days more. At the end of the dietary treatment the described parameters were examined. 1) 60 days . *p<0.05 vs Cc   Cc Cl Lc Ll SBP 124±2 141±4 * 141±5* 148±6* NOx 1.68±0.07 1.10±0.03* 1.01±0.22* 0.58±0.10* Ventricle NOS 197±3 151±5* 149±2* 139±5* Aorta NOS 231±5 161±8* 167±6* 163±12* 2) After supplementation Supplemented zinc diet induced a decrease in SBP compared with 60 days ( Lls: 123±3# ; Cls: 133±3**; #p<0.05 vs Ll and **p<0.05 vs Cl). Moreover we observed an increase in urinary NOx in Lls and Cls (Lls: 1.91±0.2#, Cls: 1.67± 0.2**; #p<0.05 vs Ll and **p<0.05 vs Cl ). An augment in cardiac NOS activity was observed in both supplemented groups compared with the animals exposed to zinc deficiency at day 60. (ventricle: Lls: 160±6#; Cls: 168±4**; aorta: Lls: 173±7#, Cls: 177±8** ; #p<0.05 vs Ll and **p<0.05 vs Cl). This work brings evidences that zinc deficiency in any period of growth predisposes to the development of high blood pressure and alteration in cardiac and vascular nitric oxide system in the adult life. A supplemented diet with zinc in the adult life after its deficiency was successful to normalize the high values of arterial blood pressure. This effect was accompanied by improve in cardiac and vascular NOS activity. Alteration in nitric oxide system could be one of the mechanisms involved in the alteration of arterial pressure regulation in zinc deficiency.