scholarly journals The Role of RBC Oxidative Stress in Sickle Cell Disease: From the Molecular Basis to Pathologic Implications

Antioxidants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1608
Author(s):  
Qinhong Wang ◽  
Rahima Zennadi

Sickle cell disease (SCD) is an inherited monogenic disorder and the most common severe hemoglobinopathy in the world. SCD is characterized by a point mutation in the β-globin gene, which results in hemoglobin (Hb) S production, leading to a variety of mechanistic and phenotypic changes within the sickle red blood cell (RBC). In SCD, the sickle RBCs are the root cause of the disease and they are a primary source of oxidative stress since sickle RBC redox state is compromised due to an imbalance between prooxidants and antioxidants. This imbalance in redox state is a result of a continuous production of reactive oxygen species (ROS) within the sickle RBC caused by the constant endogenous Hb autoxidation and NADPH oxidase activation, as well as by a deficiency in the antioxidant defense system. Accumulation of non-neutralized ROS within the sickle RBCs affects RBC membrane structure and function, leading to membrane integrity deficiency, low deformability, phosphatidylserine exposure, and release of micro-vesicles. These oxidative stress-associated RBC phenotypic modifications consequently evoke a myriad of physiological changes involved in multi-system manifestations. Thus, RBC oxidative stress in SCD can ultimately instigate major processes involved in organ damage. The critical role of the sickle RBC ROS production and its regulation in SCD pathophysiology are discussed here.

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 296
Author(s):  
Rosa Vona ◽  
Nadia Maria Sposi ◽  
Lorenza Mattia ◽  
Lucrezia Gambardella ◽  
Elisabetta Straface ◽  
...  

Sickle cell disease (SCD) is the most common hereditary disorder of hemoglobin (Hb), which affects approximately a million people worldwide. It is characterized by a single nucleotide substitution in the β-globin gene, leading to the production of abnormal sickle hemoglobin (HbS) with multi-system consequences. HbS polymerization is the primary event in SCD. Repeated polymerization and depolymerization of Hb causes oxidative stress that plays a key role in the pathophysiology of hemolysis, vessel occlusion and the following organ damage in sickle cell patients. For this reason, reactive oxidizing species and the (end)-products of their oxidative reactions have been proposed as markers of both tissue pro-oxidant status and disease severity. Although more studies are needed to clarify their role, antioxidant agents have been shown to be effective in reducing pathological consequences of the disease by preventing oxidative damage in SCD, i.e., by decreasing the oxidant formation or repairing the induced damage. An improved understanding of oxidative stress will lead to targeted antioxidant therapies that should prevent or delay the development of organ complications in this patient population.


Genes ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 144
Author(s):  
Olivia Edwards ◽  
Alicia Burris ◽  
Josh Lua ◽  
Diana J. Wilkie ◽  
Miriam O. Ezenwa ◽  
...  

This review outlines the current clinical research investigating how the haptoglobin (Hp) genetic polymorphism and stroke occurrence are implicated in sickle cell disease (SCD) pathophysiology. Hp is a blood serum glycoprotein responsible for binding and removing toxic free hemoglobin from the vasculature. The role of Hp in patients with SCD is critical in combating blood toxicity, inflammation, oxidative stress, and even stroke. Ischemic stroke occurs when a blocked vessel decreases oxygen delivery in the blood to cerebral tissue and is commonly associated with SCD. Due to the malformed red blood cells of sickle hemoglobin S, blockage of blood flow is much more prevalent in patients with SCD. This review is the first to evaluate the role of the Hp polymorphism in the incidence of stroke in patients with SCD. Overall, the data compiled in this review suggest that further studies should be conducted to reveal and evaluate potential clinical advancements for gene therapy and Hp infusions.


Author(s):  
Rosa Vona ◽  
Nadia Maria Sposi ◽  
Lorenza Mattia ◽  
Lucrezia Gambardella ◽  
Elisabetta Straface ◽  
...  

Sickle cell disease (SCD) is the most common hereditary disorder of hemoglobin (Hb) that affects approximately a millions people worldwide. It is characterized by a single nucleotide substitution on the β-globin gene, leading to the production of abnormal sickle hemoglobin with multi-system consequences. Mutated Hb leads to profound changes in: i) red blood cell metabolism and physiology; ii) endothelial signaling; and iii) immune response. Oxidative stress is an important hallmark of SCD. It plays a key role in the pathophysiology of hemolysis, vessel occlusion and the following organ damage in sickle cell patients. For this reason, reactive oxidizing species and the (end)-products of their oxidative reactions have been proposed as markers of both tissue pro-oxidant status and disease severity. Although more studies are needed to clarify their role, antioxidant agents have been shown to be effective in reducing pathological consequences of the disease by preventing oxidative damage in SCD, i.e. by decreasing the oxidant formation or repairing the induced damage. An improved understanding of oxidative stress will lead to targeted antioxidant therapies that should prevent or delay the development of organ complications in this patient population.


2019 ◽  
Vol 94 (3) ◽  
pp. 327-337 ◽  
Author(s):  
Gregory M. Vercellotti ◽  
Agustin P. Dalmasso ◽  
Terry R. Schaid ◽  
Julia Nguyen ◽  
Chunsheng Chen ◽  
...  

2019 ◽  
Vol 8 (10) ◽  
pp. 1690 ◽  
Author(s):  
Saranya Veluswamy ◽  
Payal Shah ◽  
Christopher Denton ◽  
Patjanaporn Chalacheva ◽  
Michael Khoo ◽  
...  

Sickle cell disease (SCD) is an inherited hemoglobinopathy characterized by polymerization of hemoglobin S upon deoxygenation that results in the formation of rigid sickled-shaped red blood cells that can occlude the microvasculature, which leads to sudden onsets of pain. The severity of vaso-occlusive crises (VOC) is quite variable among patients, which is not fully explained by their genetic and biological profiles. The mechanism that initiates the transition from steady state to VOC remains unknown, as is the role of clinically reported triggers such as stress, cold and pain. The rate of hemoglobin S polymerization after deoxygenation is an important determinant of vaso-occlusion. Similarly, the microvascular blood flow rate plays a critical role as fast-moving red blood cells are better able to escape the microvasculature before polymerization of deoxy-hemoglobin S causes the red cells to become rigid and lodge in small vessels. The role of the autonomic nervous system (ANS) activity in VOC initiation and propagation has been underestimated considering that the ANS is the major regulator of microvascular blood flow and that most triggers of VOC can alter the autonomic balance. Here, we will briefly review the evidence supporting the presence of ANS dysfunction in SCD, its implications in the onset of VOC, and how differences in autonomic vasoreactivity might potentially contribute to variability in VOC severity.


Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 960-960
Author(s):  
Xingguo Zhu ◽  
Betty S. Pace

The basic leucine zipper transcription factor, nuclear factor (erythroid-derived 2)-like 2 (NRF2) plays a critical role in the cellular antioxidant response to control oxidative stress. We and others previously demonstrated that NRF2 activation enhances γ-globin gene transcription and fetal hemoglobin expression in human primary erythroid progenitors through changes in chromatin structure (Zhu et al., Haematologica 2017). In this study, we investigated the protective role of NRF2 in reversing the pathophysiology of sickle cell disease (SCD) in a SCD/NRF2 knockout (SCD/NRF2KO) transgenic model created in our lab by crossbreeding Townes SCD mice (Ryan et al., Science 1997) and NRF2 knockout mice (Kuroha et al., J Biochem 1998). The NRF2 gene is transmitted through autosomal recessive Mendelian genetics for wild-type, heterozygote and NRF2KO pups. By contrast, the SCD/NRF2KO genotype was present in <2% of pups. In addition, the fertility and litter size of SCD/NRF2KO females were lower than SCDWT mice, suggesting a critical role of NRF2 in the survival of pups during gestation. To determine the hematopoietic effect of NRF2KO in SCD, we monitored the complete blood count with differential and reticulocyte count. There was no significant change in any parameters except higher total white blood cell counts in the SS/NRF2KO mouse suggesting increased inflammation. Examination of globin gene expression patterns in SS/NRF2KO mice showed reduced γ-globin gene expression during erythroid differentiation in the E13.5 and E18.5 fetal liver, adult spleen and bone marrow. In addition, peripheral blood red cells had a 33% increase (p<0.05) in reactive oxygen species and a significant 38% increase in sickling under in vitro hypoxic conditions. We next characterized the effects of NRF2 loss on organ pathology. The SCD/NRF2KO mice displayed greater splenomegaly indicating exaggerated hemolysis most likely due to high levels of reactive oxygen species. By 8-10 weeks of age, the SCD/NRF2KO mouse showed significant inflammation by hematoxylin-eosin staining of the spleen, lung and liver when compared to SCD/NRF2WT mice. Protein expression profiling by western blotting using adult spleen demonstrated downregulation of the antioxidant proteins heme oxygenase 1 (HMOX1), NADPH: quinone oxidoreductase 1 (NQO1) and catalase by 31%, 60%, and 48% respectively (p<0.05). To further support a severe disease phenotype, the expression of intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) were increased by 1.7-fold and 2.3-fold (p<0.05) while vascular endothelial growth factor (VEGF) levels were not changed. Lastly, the expression of interleukin 1β (IL-1β), IL-6, tumor necrosis factor α (TNF-α), monocyte chemoattractant protein (MCP-1) and macrophage migration inhibitory factor (MIF-1) was elevated in SCD/NRF2KO mice compared to SCDWT mice. These data validate a critical role of NRF2 in ameliorating the phenotypic severity of SCD by protecting against red blood cell sickling, oxidative stress and tissue inflammation. Furthermore, the ability of NRF2 to mediate fetal hemoglobin induction provides a rationale for the development of therapeutic agents that activate NRF2 expression. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2324-2324
Author(s):  
Kirkwood A. Pritchard ◽  
Jingli Wang ◽  
Hao Xu ◽  
Deron W. Jones ◽  
Sandra L. Holzhauer ◽  
...  

Abstract Background: Vasoregulation is impaired in human and murine sickle cell disease (SCD). Chronic inflammation and oxidative stress impair vasodilation. High-density lipoprotein (HDL) plays an important role in attenuating inflammatory responses. Previously we showed 4F, an apoA-I mimetic designed to improve HDL function, dramatically restores vasodilation in SCD mice. Here, we examine mechanisms by which D-4F restores vasodilation in SCD mice and in mice made to develop SCD via fetal liver hematopoietic stem cell transplantation (HSCT). Effects of proinflammatory lipids and D-4F were determined in HSCT-SCD- LDL receptor null (Ldlr−/−) mice fed either chow or western diet (WD). The role of HDL was examined in HSCT-SCD-apoA-I null (apoA-I−/−) mice. Finally, the role of eNOS was examined in HSCT-SCD-eNOS deficient (eNOS−/−) mice. Mice were treated with or without D-4F (1mg/kg/d for 6–8 wks). Results: Total cholesterol concentrations in HSCT-SCD-Ldlr−/− mice fed lab chow were slightly increased compared to transgenic SCD mice (40–60 vs. 90–130 mg/dL, p<0.05) with no change in HDL. Acetylcholine-mediated vasodilation (Ach, 10-7 to 10-4M) in HSCT-SCD-Ldlr−/− mice was impaired compared to untreated non-SCD Ldlr−/− mice (10 vs 43%, p<0.05). D-4F restored eNOS-dependent vasodilation in HSCT-SCD-Ldlr−/− mice to the level in non-SCD Ldlr−/− mice. D-4F did not alter total cholesterol or HDL in HSCT-SCD-Ldlr−/− mice but did decrease proinflammatory HDL (580 vs 380, p<0.05), an index of oxidizability. In contrast to HSCT-SCD-Ldlr−/− mice fed chow diet, HSCT-SCD-Ldlr−/− mice fed WD had little to no ACh vasodilation (0–3%). D-4F increased vasodilation slightly in HSCT-SCD-Ldlr−/− fed WD (~12%). Total cholesterol and HDL increased in response to WD in HSCT-SCD-Ldlr−/− mice (p<0.01). D-4F induced minimal changes in total cholesterol, HDL or proinflammatory HDL in these mice. To examine the role of HDL, we found that vasodilation in HSCT-SCD-apoA-I−/− mice was reduced to ~25% compared to 65% in C57BL/6 mice (p<0.01). D-4F nearly doubled vasodilation to ~43% in HSCT-SCD-apoA-I−/− mice (p<0.05). L-NAME (100μM) blocked vasodilation in all HSCT-SCD-apoA-I−/− mice, indicating vasodilation was mediated exclusively by eNOS. In contrast, when we examined the effect of eNOS deficiency, ACh induced minimal increases in vasodilation (~22%). Dissection of cellular mechanisms mediating vasodilation revealed that a small portion HSCT-SCD-eNOS−/− mice was inhibited by L-NAME (i.e., NOS, ~12%), with none mediated by COX-prostacyclin (0%) and a small portion mediated by cytochrome P450 (~10%). Inhibitor studies revealed D-4F restored vasodilation in HSCT-SCD-eNOS−/− mice to ~52% (p<0.05) by predominately a L-NAME-inhibitable mechanism (NOS = 40%; COX-prostacylcin = 0% and cytochrome P450 = 11%). Conclusions: D-4F improves eNOS-dependent vasodilation even when hypercholesterolemia is superimposed on SCD. Measurements of proinflammatory HDL reveal D-4F restores vasodilation by protecting HDL against oxidation. Interestingly, D-4F protects vasodilation even in mice that have low levels of apoA-I-deficient HDL. Taken together, these data indicate proinflammatory HDL plays a critical role in mechanisms by which SCD impairs eNOS-dependent vasodilation and D-4F increases vasodilation, at least in part, by decreasing proinflammatory HDL in SCD.


2019 ◽  
Vol 7 (2) ◽  
pp. 17 ◽  
Author(s):  
Charles Antwi-Boasiako ◽  
Gifty Dankwah ◽  
Robert Aryee ◽  
Charles Hayfron-Benjamin ◽  
Eric Donkor ◽  
...  

Oxidative stress plays a very significant role in the pathophysiology of sickle cell disease (SCD) and associated complications. Oxidative stress, which is often experienced by SCD patients as a result of continuous production of reactive oxygen species (ROS), may lead to endothelial dysfunction and acute inflammation. Antioxidant enzymes, such as superoxide dismutase (SOD) and catalase (CAT), often play a protective role. The current study aimed at determining the oxidative profile of persons with SCD at a tertiary hospital in Ghana. This was a case-control study involving 90 patients with SCD (34 HbSS patients at steady state, 30 HbSC at steady state, 15 HbSS with vaso-occlusive crisis, 11 HbSC with vaso-occlusive crisis), and 50 HbAA control group. Whole blood samples were collected from the study participants and analyzed for full blood counts. The blood samples were assayed for SOD and CAT as a measure of antioxidant defense, while lipid peroxidation was quantified as malondialdehyde (MDA). The results showed that the levels of SOD and CAT were significantly lower in SCD patients as compared to the control group. Patients with HbSS vaso-occlusive crisis had the lowest levels of SOD and CAT. The difference in SOD levels between HbSS at steady state and HbSC with vaso-occlusive crisis was, however, not significant (p = 0.228). The MDA level was significantly higher in SCD patients compared to the control group. This study concludes that the levels of various antioxidant enzymes (erythrocyte SOD and erythrocyte CAT) and oxidative marker (MDA) and are altered in SCD patients.


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