On the Effects of Reactive Oxygen Species and Nitric Oxide on Red Blood Cell Deformability

Abstract

The main function of red blood cells (RBCs) is the transport of respiratory gases along the vascular tree. To fulfill their task, RBCs are able to elastically deform in response to mechanical forces and, pass through the narrow vessels of the microcirculation. Decreased RBC deformability was observed in pathological conditions linked to increased oxidative stress or decreased nitric oxide (NO) bioavailability, like hypertension. Treatments with oxidants and with NO were shown to affect RBC deformability ex vivo, but the mechanisms underpinning these effects are unknown. In this study we investigate whether changes in intracellular redox status/oxidative stress or nitrosation reactions induced by reactive oxygen species (ROS) or NO may affect RBC deformability. In a case-control study comparing RBCs from healthy and hypertensive participants, we found that RBC deformability was decreased, and levels of ROS were increased in RBCs from hypertensive patients as compared to RBCs from aged-matched healthy controls, while NO levels in RBCs were not significantly different. To study the effects of oxidants on RBC redox state and deformability, RBCs from healthy volunteers were treated with increasing concentrations of tert-butylhydroperoxide (t-BuOOH). We found that high concentrations of t-BuOOH (≥ 1 mM) significantly decreased the GSH/GSSG ratio in RBCs, decreased RBC deformability and increased blood bulk viscosity. Moreover, RBCs from Nrf2 knockout (KO) mice, a strain genetically deficient in a number of antioxidant/reducing enzymes, were more susceptible to t-BuOOH-induced impairment in RBC deformability as compared to wild type (WT) mice. To study the role of NO in RBC deformability we treated RBC suspensions from human volunteers with NO donors and nitrosothiols and analyzed deformability of RBCs from mice lacking the endothelial NO synthase (eNOS). We found that NO donors induced S-nitrosation of the cytoskeletal protein spectrin, but did not affect human RBC deformability or blood bulk viscosity; moreover, under unstressed conditions RBCs from eNOS KO mice showed fully preserved RBC deformability as compared to WT mice. Pre-treatment of human RBCs with nitrosothiols rescued t-BuOOH-mediated loss of RBC deformability. Taken together, these findings suggest that NO does not affect RBC deformability per se, but preserves RBC deformability in conditions of oxidative stress.

Fenretinide treatment accelerates atherosclerosis development in apoE‐deficient mice in spite of beneficial metabolic effects

“…Erythrolysis was a condition found only in EKO mice and possibly consequent to the severe hypercholesterolaemia that has been shown to increase the osmotic fragility of RBC (Fessler, Rose, Zhang, Jaramillo, & Zeldin, 2013). In addition, fenretinide treatment is associated to an augmented ROS production (Cuperus, Leen, Tytgat, Caron, & van Kuilenburg, 2010), which in turn reduces RBC deformability (Diederich et al, 2018). These two effects are synergized in EKO-Fen only, leading to peripheral haemolysis.…”

Hydroxyurea therapy modulates sickle cell anemia red blood cell physiology: Impact on RBC deformability, oxidative stress, nitrite levels and nitric oxide synthase signalling pathway

“…Very recently, a study by Diederich reported that NO donors would be able to preserve RBC deformability in situations where oxidative stress would be enhanced [49]. Oxidative stress plays a critical role in the pathophysiology of SCA [50].…”

Red blood cells: the forgotten player in hemostasis and thrombosis

“…This review will briefly summarize what is currently known about the involvement of RBCs in hemostasis and thrombosis and its underappreciated importance. RBCs increase blood viscosity because of a rise in hematocrit, an increase in RBC aggregation or a decrease in RBC deformability (increasing flow resistance) Pro [2][3][4][5] Conversely, anemia is associated with low blood viscosity and bleeding tendency as a result of reduced platelet margination toward endothelium and enhanced NO availability Anti [2][3][4][5] RBCs undergo shear-dependent reversible aggregation mediated by plasma proteins (mainly fibrinogen and immunoglobulins) and/or local osmotic gradient Pro [14][15][16][70][71][72][73][74] RBCs with increased rigidity occlude small vessels Pro [11,12] Deformability of RBCs reduces frictional resistance to flow Anti [8,[11][12][13]] RBCs maintain biconcave shape and a high surface-to-volume ratio as a result of cytoskeleton and water/ions balance Pro or anti [5] RBCs migrate to the center of blood flow and push platelets toward the endothelium (margination) in a hematocrit-and shear-dependent manner Pro [59][60][61] Effects on platelet reactivity RBCs increase platelet adhesion and aggregation by release of ADP and thromboxane A 2 Pro [66,67] RBCs form aggregates with platelets via adhesive molecules (ICAM-4 and fibrinogen with aIIbb3)…”