Valutazione dei fattori che influenzano l’attività reninica plasmatica e l’aldosteronemia nella prima infanzia

Renin-angiotesin-aldosterone system (RAA) was investigated in 36 children 20 days to 23 months old, with different dietary electrolyte intakes. Plasma rennin activity (PRA) and Plasma aldosterone level (P-aldo) were related to sodium and potassium intake (NaD, KD) and to sodium and potassium excretion (NaU, KU) expressed in mEq/kg/day and to the age. The children, divided in 3 groups (A, B, C), received respectively: NaD (0.93 +/- 0.03 mEq in the group A, 2.14 +/- 0.10 mEq in the group B, 2.32 +/- 0.23 mEq in the group C) and KD (1.77 +/- 0.07 mEq in the group A, 3.14 +/- 0.14 mEq in the group B, 0.25 +/- 0.03 mEq in the group C). No correlation was found between PRA, NaD-KD, NaU-KU and age in the groups examined. A significant inverse correlation was observed P-aldo, NaD (p<0.001), NaU (p<0.002), and age (p<0.01). A positive correlation was found between P-aldo and KD (p<0.005), and a borderline positive correlation between P-aldo and KU (p<0.06) for B-C groups only. PRA and P-aldo were positively correlated (p<0.002) in the three groups, when considered all together. These results suggests some considerations on RAA system in early infancy: (1) the age is probably the most important factor influencing the PRA high value in younger children; (2) Na dietary intake is certainly the most important factor influencing the P-aldo variations in the same period of life.