Erythrocyte Passive Potassium Flux is Increased in Patients with Ischemic Coronary Disease (ICD) and in Subjects with Family History of ICD

Abstract

Background. It has been proposed that ischemic coronary disease (ICD) associated potassium loss could be due to modifications of potassium permeability. We investigated whether a positive family history of ICD can influence this parameter. We have compared potassium permeability in erythrocytes from ICD patients and from positive family history subjects (FICD) with control subjects. Methods. All patients and subjects were carefully selected for the absence of hypertension and dysmetabolic pathologies. ICD group: 24 patients (19 males, 5 females; ages 43 to 69) all affected by ischemic coronary disease, under no drug treatment; FICD group: 18 subjects (all males, ages 27 to 42) with a verified positive ICD family history, without hypertensive family history and cardiovascular pathology; control group: 16 subjects (11 males, 5 females; ages 28 to 48) without positive family history of ICD. Passive potassium efflux (PPE) was spectrophotometrically measured in K-free medium containing ouabain and bumetanide. The kinetic constant was calculated by dividing PPE by the erythrocyte potassium concentration. Results. No statistically significant differences were noted between the intracellular potassium content of the three groups. However, (1) the passive potassium permeability of the ICD group was significantly higher (kK=0.055 ±0.021 h-1, n=24) than that of the control group (kK=0.023 ±0.008 h-1, n=16; p<0.00001), (2) the FICD group was higher (kK=0.036 ±0.012 h-1, n=18) than the control group (p<0.001), and (3) the ICD group was higher than the FICD group (p<0.001). Conclusions. Our results suggest an inheritability of ICD, paralleling the familial aggre gation of the pathology. Erythrocyte potassium permeability could represent an early marker of ischemic coronary disease and be used as a prophylactic tool.