Sistemi di trasporto transmembrana del Na ⁺ in forme diverse di iperlipoproteinemia

The possible interrelationships between the erythrocytic transport systems of Na ⁺ (Na ⁺/K ⁺ pump, Na ⁺/K ⁺ cotransport, Na ⁺/Li ⁺ countertransport, Na ⁺ passive permeability) and the plasmatic lipids (cholesterol, triglycerides, HDL, LDL, apoprotein A1, apoprotein B) were studied in 42 normotensive subjects with different forms of hyperlipoproteinaemia and with a negative familiarity for arterial hypertension. In subjects with hypercholesterolaemia (hyperlipoproteinaemia II A and II B) an elevated activity of the Na ⁺/K ⁺ pump was noticed, while in subjects with hypertriglyceridaemia (type IV) an increase in Na ⁺ passive permeability and Na ⁺/Li ⁺ countertransport with a lower level of intraerythrocytic Na ⁺ was shown. A negative correlation was observed between the total efflux of Na ⁺ and Na ⁺/K ⁺ pump and the levels of cholesterol (r = -0.43, p <0.04 and r = -0.41, p <0.05) and the apoprotein B/A ratio (r = -0.42, p <0.05 and r = -0.50, p <0.01). A negative correlation was also noticed between the Na ⁺/K ⁺ pump and the levels of apoprotein B (r = -0.41, p <0.05). The Na ⁺/K ⁺ cotransport appeared inversely correlated with the levels of HDL cholesterol (r = -0.42, p <0.05), while the Na ⁺ passive permeability was negatively correlated with the levels of LDL (r = -0.43, p <0.04) and positively correlated with the plasmatic triglycerides (r = +0.54, p <0.01). Such data show that the plasmatic lipids can influence the systems of transmembrane ionic transport of Na ⁺ and play an important role also this way, in cardiovascular pathology.