Uremia and Red Blood Cell Sodium Transport

Influence of Sodium Balance on Uremic Red Blood Cell Ion Transport

“…For the cotransport, Quarello et al [17] noted an increase in this activity after acetate buffer HD although in our study, there was no statistically significant difference for the mean value of this transport system activity before and after dialysis with the same acetate buffer. However, we noted intraindividual differences: some patients exhibit an increase, others a decrease in cotransport activity during dialysis: this is in agreement with the observations of Diez et al [12], Finally, in accordance with the findings of Quarello et al [17], the improvement in the ouabain-sensitive Na-K pump activity was found to be strongly correlated with the amount of water and sodium removed during dialy sis; Indeed, we have observed the primordial importance of volume depletion on this RBC pump activity which was not statistically improved after dialysis without ultra filtration. There is also a trend for a negative correlation between variations of blood pressure and pump activity induced by dialysis.…”

“…While for cotransport or countertransport, Diez et al [12] confirm our observation, these authors found a de crease in the RBC sodium leak of uremic subjects. This discrepancy could perhaps be explained by a difference in plasma bicarbonate concentration.…”

“…This observation was confirmed by others [11,12] and related to the accumulation of so-called uremic toxins [13].…”

Uremia and Red Blood Cell Lithium-Sodium Countertransport

“…Patients, on the average, have a 28% increase in the maximal velocity of the lithium-stimulated sodium efflux compared to con trols and this difference reaches statistical significance at the 0.05 level. Both the findings of Diez et al [1] and our own findings are in agreement with the suggestion of Woods et al [3] of an increased countertransport in uremic patients. The conclusions therefore from the re port of Diez et al [1] should be that, in addition to the ouabain-sensitive Na efflux (Na-K pump) and the bumetamide-sensitive Na efflux (Na/K cotransport), uremia affects the lithium-stimulated sodium efflux (NaLi countertransport) and that this latter alteration seems to be reversed after renal transplantation.…”

“…Both the findings of Diez et al [1] and our own findings are in agreement with the suggestion of Woods et al [3] of an increased countertransport in uremic patients. The conclusions therefore from the re port of Diez et al [1] should be that, in addition to the ouabain-sensitive Na efflux (Na-K pump) and the bumetamide-sensitive Na efflux (Na/K cotransport), uremia affects the lithium-stimulated sodium efflux (NaLi countertransport) and that this latter alteration seems to be reversed after renal transplantation. The difference detected between the hemodialysis patients and controls in the report of Diez et al is similar to the difference found between male normotensives and essential hyper tensive patients [4].…”