Erythrocyte Sodium Sensitivity and Eryptosis in Chronic Hemodialysis Patients

Abstract

Background/Aims: In hemodialysis (HD) patients the endothelial and erythrocyte glycocalyx is impaired which in turn correlates with elevated erythrocyte sodium sensitivity (ESS). Additionally, apoptotic erythrocyte death (eryptosis), characterized by phosphatidylserine (PS) exposure on the cell surface, is increased in this population. We aimed to explore the relationship of ESS and eryptosis. Methods: Blood samples were collected from 11 healthy controls and 20 chronic HD patients before and after midweek HD. ESS was quantified by the salt blood test. PS-exposure, intracellular reactive oxygen species (ROS) of erythrocytes and reticulocytes were assessed by flow cytometry. Results: Compared to controls ESS was significantly higher in HD patients preHD and did not change during treatment. The percentage of eryptotic cells did not differ between controls and patients preHD. However, eryptosis decreased during HD. ESS and eryptosis were uncorrelated, while eryptosis was positively correlated with intracellular ROS and percent reticulocytes. Conclusions: Higher ESS levels in HD patients indicate a pathologic glycocalyx. ESS and eryptosis were not correlated. The decreased eryptosis postHD may possibly be related to dialytic uremic toxin removal, but is likely multifactorial. The relationship between eryptosis and intracellular ROS warrants further research.

Keywords

• Oxidative stress
• Reactive oxygen species
• Salt blood test
• Sodium buffer capacity
• Erythrocyte death
• End stage renal disease
• Eryptosis
• Glycocalyx