scholarly journals Erythrocyte glutamine depletion, altered redox environment, and pulmonary hypertension in sickle cell disease

Blood ◽  
2008 ◽  
Vol 111 (1) ◽  
pp. 402-410 ◽  
Author(s):  
Claudia R. Morris ◽  
Jung H. Suh ◽  
Ward Hagar ◽  
Sandra Larkin ◽  
D. Anton Bland ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Pulmonary Hypertension ◽  
Sickle Cell Disease ◽  
Healthy Volunteers ◽  
Sickle Cell ◽  
Glutamine Metabolism ◽  
Cell Disease ◽  
Total Glutathione ◽  
Redox Environment ◽  
And Oxidative Stress

Erythrocyte glutathione depletion has been linked to hemolysis and oxidative stress. Glutamine plays an additional antioxidant role through preservation of intracellular nicotinamide adenine dinucleotide phosphate (NADPH) levels, required for glutathione recycling. Decreased nitric oxide (NO) bioavailability, which occurs in the setting of increased hemolysis and oxidative stress, contributes to the pathogenesis of pulmonary hypertension (PH) in sickle cell disease (SCD). We hypothesized that altered glutathione and glutamine metabolism play a role in this process. Total glutathione (and its precursors) and glutamine were assayed in plasma and erythrocytes of 40 SCD patients and 9 healthy volunteers. Erythrocyte total glutathione and glutamine levels were significantly lower in SCD patients than in healthy volunteers. Glutamine depletion was independently associated with PH, defined as a tricuspid regurgitant jet velocity (TRV) of at least 2.5 m/s. The ratio of erythrocyte glutamine:glutamate correlated inversely to TRV (r = −0.62, P < .001), plasma arginase concentration (r = −0.45, P = .002), and plasma-free hemoglobin level (r = −0.41, P = .01), linking erythrocyte glutamine depletion to dysregulation of the arginine-NO pathway and increased hemolytic rate. Decreased erythrocyte glutathione and glutamine levels contribute to alterations in the erythrocyte redox environment, which may compromise erythrocyte integrity, contribute to hemolysis, and play a role in the pathogenesis of PH of SCD.

Low Erythrocyte Glutamine-to-Glutamate Ratio: A Novel Biomarker of Hemolysis and Pulmonary Hypertension in Sickle Cell Disease.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2257-2257
Author(s):  
Claudia R. Morris ◽  
Jung Suh ◽  
Ward Hagar ◽  
Sandra Larkin ◽  
D. Anton Bland ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
De Novo ◽  
Glutamine Metabolism ◽  
Cell Disease ◽  
Total Glutathione ◽  
Redox Environment ◽  
No Bioavailability ◽  
Thiol Redox

Abstract The erythrocyte redox environment may contribute to increased hemolysis and decreased nitric oxide (NO) bioavailability in pulmonary hypertension (PH) of sickle cell disease (SCD). Glutathione (GSH) is the principal thiol redox buffer in erythocytes and its depletion has been linked to hemolysis. Glutamine plays an additional anti-oxidant role through preservation of the intracellular nicotinamide adenine dinucleotide (NAD) levels, required for reducing GSSG back to GSH. We hypothesized that altered GSH and glutamine metabolism promotes hemolysis and contributes to PH in SCD. Glutamine, total glutathione (GSH+GSSG) and its precursors (glutamate, cysteine, glycine) were assayed in plasma and erythrocytes of 40 SCD patients and 9 controls. PH is defined by echocardiogram as a tricuspid regurgitant jet velocity (TRV) ≥ 2.5m/s. Total plasma glutathione was lower in SCD vs control patients (2.7 ± 0.3 μM vs. 4.1± 0.8 μM, p&lt;0.05). Similarly, total erythrocyte glutathione levels were decreased in SCD vs. control patients (310 ± 26 μM vs. 683 ± 110 μM, p&lt;0.0001). A trend towards higher GSH precursor levels identified in plasma and erythrocyte compartments suggests that the total glutathione (GSH+GSSG) deficit is due to heightened rate of GSH utilization rather than decreased synthesis capacity. While severity of erythrocyte GSH depletion was similar in SCD patients with and without PH, erythrocyte glutamine levels differed significantly (482±92μM, n=17 vs 934±134μM, n=23, p&lt;0.02) and values inversely correlated to TRV (r = −0.51, p&lt;0.0001). As glutamine is required for de novo synthesis of NAD(P)+ essential for GSH recycling, lower steady-state glutamine levels may reflect enhanced GSH utilization rates in the SCD erythrocytes. A significant reduction in the erythrocyte glutamine:glutamate ratio occurred in SCD patients compared with normal volunteers, with the lowest ratios observed in SCD patients with PH. The glutamine:glutamate ratio, potentially a gauge of NADPH biosynthesis and oxidative stress, was inversely correlated with TRV (r = −0.62, p&lt;0.001), implicating glutamine bioavailability as a novel factor in the pathophysiology of PH. Changes in the glutamine:glutamate ratio were predominantly caused by decreased erythrocyte glutamine levels rather than increased glutamate levels, ruling out an effect on the ratio from increased cellular glutamine uptake. Erythrocyte glutamine:glutamate ratio correlated with age in patients with SCD (r = −0.33, p=0.04), and inversely correlated with plasma arginase concentratoin (r= −0.45, p=0.012), and plasma-Hb (r= −0.41, p=0.01), linking lower glutamine bioavailability to increased red cell derived plasma arginase, hemolysis and potentially with increased mortality in PH of SCD as previously reported (Morris et al, JAMA 2005). Decreased erythrocyte total glutathione and glutamine levels contribute to alterations in the erythrocyte redox environment, which compromise erythrocyte integrity and NO bioavailability and may play a role in hemolysis and the pathogenesis of PH of SCD.

scholarly journals Arginine therapy of transgenic-knockout sickle mice improves microvascular function by reducing non-nitric oxide vasodilators, hemolysis, and oxidative stress

2008 ◽  
Vol 295 (1) ◽  
pp. H39-H47 ◽  
Author(s):  
Dhananjay K. Kaul ◽  
Xiaoqin Zhang ◽  
Trisha Dasgupta ◽  
Mary E. Fabry
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Vascular Reactivity ◽  
Microvascular Function ◽  
Cell Disease ◽  
No Bioavailability ◽  
Cox 2 ◽  
And Oxidative Stress

In sickle cell disease, nitric oxide (NO) depletion by cell-free plasma hemoglobin and/or oxygen radicals is associated with arginine deficiency, impaired NO bioavailability, and chronic oxidative stress. In transgenic-knockout sickle (BERK) mice that express exclusively human α- and βS-globins, reduced NO bioavailability is associated with induction of non-NO vasodilator enzyme, cyclooxygenase (COX)-2, and impaired NO-mediated vascular reactivity. We hypothesized that enhanced NO bioavailability in sickle mice will abate activity of non-NO vasodilators, improve vascular reactivity, decrease hemolysis, and reduce oxidative stress. Arginine treatment of BERK mice (5% arginine in mouse chow for 15 days) significantly reduced expression of non-NO vasodilators COX-2 and heme oxygenase-1. The decreased COX-2 expression resulted in reduced prostaglandin E2(PGE2) levels. The reduced expression of non-NO vasodilators was associated with significantly decreased arteriolar dilation and markedly improved NO-mediated vascular reactivity. Arginine markedly decreased hemolysis and oxidative stress and enhanced NO bioavailability. Importantly, arteriolar diameter response to a NO donor (sodium nitroprusside) was strongly correlated with hemolytic rate (and nitrotyrosine formation), suggesting that the improved microvascular function was a response to reduced hemolysis. These results provide a strong rationale for therapeutic use of arginine in sickle cell disease and other hemolytic diseases.

2D DIGE based proteomics study of erythrocyte cytosol in sickle cell disease: Altered proteostasis and oxidative stress

PROTEOMICS ◽  
2013 ◽  
Vol 13 (21) ◽  
pp. 3233-3242 ◽  
Author(s):  
Avik Basu ◽  
Sutapa Saha ◽  
Shilpita Karmakar ◽  
Sudipa Chakravarty ◽  
Debasis Banerjee ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Cell Disease ◽  
2D Dige ◽  
Proteomics Study ◽  
And Oxidative Stress

Differential Effects of Lovastatin and Allopurinol Therapy in a Murine Model of Sickle Cell Disease.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2325-2325
Author(s):  
Kirkwood A. Pritchard ◽  
Terri L. Besch ◽  
Jingli Wang ◽  
Hao Xu ◽  
Deron W. Jones ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Sickle Cell Disease ◽  
Reperfusion Injury ◽  
Xanthine Oxidase ◽  
Sickle Cell ◽  
Vascular Function ◽  
Ischemia Reperfusion ◽  
Pleiotropic Effects ◽  
Cell Disease ◽  
And Oxidative Stress

Abstract Sickle cell disease is characterized by a chronic state of inflammation and oxidative stress due to repetitive bouts of ischemia and reperfusion injury. Ischemia-reperfusion injury increases the release of xanthine oxidase, which binds to vascular endothelium at sites distant from the original site of tissue damage where it can generate reactive oxygen species and impair normal vascular function. Lovastatin, an HMG COA reductase inhibitor, is a cholesterol lowering pharmaceutical agent use to treat hypercholesterolemia and prevent the premature development of atherosclerosis. Although lovastatin is used primarily to treat hypercholesterolemia, this agent has beneficial, pleiotropic effects that decrease vascular inflammation and improve vasodilation by increasing endothelial nitric oxide synthase (eNOS) in vascular tissues, a desired end-point in sickle cell disease. To test the hypothesis that xanthine oxidase plays an important role in the mechanisms by which sickle cell disease impairs vasodilation and to determine whether the pleiotropic effects of lovastatin can improve vasodilation, Berkeley transgenic sickle cell disease mice (SCD mice) were treated with either placebo, allopurinol (10 mg/kg/d, ip) or lovastatin (25 mg/kg/d by gavage) for 6–8 weeks. At the end of this treatment period, mice were sacrificed and facialis arteries removed by microdissection from a branch of the carotid artery. The facialis arteries were cannulated, pressurized to 60 mmHg, preconstricted with U46619 (10−8 to 10−7M) and then vasodilation responses to acetylcholine (ACh,10−7 to 10−4M) determined by videomicroscopy. Under these conditions, vasodilation of facialis arteries isolated from untreated SCD mice is completely impaired, with little to no response to ACh. Allopurinol treatment markedly improved ACh-induced vasodilation to nearly 40% at the highest concentration of Ach tested. Pretreatment of the isolated and pressurized vessels with L-NAME reduced vasodilation in the allopurinol-treated SCD mice to 13%, indicating that allopurinol increases eNOS-dependent vasodilation by 27% (40%-13%=27%) compared to 0% in placebo-treated SCD mice. In contrast, lovastatin, which is said to increase vascular function by increasing eNOS activity, increased ACh-induced to only 12%. Pretreatment of isolated and pressurized vessels from lovastatin-treated SCD mice with L-NAME reduced vasodilation to approximately 3%. Thus, lovastatin improved eNOS-dependent vasodilation in the SCD mice by approximately 9% (12%-3%=9%) compared to a 0% change in placebo-treated SCD mice. These data suggest that although lovastatin may protect vascular function in hypercholesterolemia, the inflammation and oxidative stress in sickle cell disease exceeds or prevents lovastatin’s purported pleiotrophic effect on arteriolar vasodilation. Thus in sickle cell disease, any increase in eNOS induced by lovastatin may be prone to dysfunction. In contrast, inhibiting xanthine oxidase released from ischemic tissues using allopurinol markedly increases vasodilation suggesting a dominant role for xanthine oxidase in inducing vascular dysfunction in sickle cell disease.

Oral Arginine Increases Erythrocyte Glutathione Levels in Sickle Cell Disease: Implications for Pulmonary Hypertension.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1208-1208 ◽  
Author(s):  
Claudia R. Morris ◽  
Jung Suh ◽  
Elliott P. Vichinsky ◽  
Elizabeth S. Klings ◽  
Martin H. Steinberg ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Pulmonary Hypertension ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Strong Predictor ◽  
No Production ◽  
Cell Disease ◽  
Plasma Hemoglobin ◽  
Before And After ◽  
Tandem Mass Spectrometric

Abstract Background: Pulmonary hypertension (PHT) is a strong predictor of mortality in sickle cell disease (SCD), and is associated with dysregulation of the arginine-nitric oxide (NO) pathway. This is in part the consequence of hemolysis, as erythrocyte release of plasma hemoglobin consumes NO, while simultaneous release of arginase consumes arginine, the substrate for NO production. The arginase-induced shift towards ornithine metabolism may then contribute to the proliferative changes in the lungs and vasculature associated with PHT through excess production of proline and polyamines. Glutathione (GSH) depletion may contribute to oxidative stress and pre-dispose sickle erythrocytes to hemolysis. We have found that erythrocyte GSH depletion is associated with severity of anemia and PHT measured by Doppler echocardiography (Morris C, Klings E, unpublished data). Kaul et al recently demonstrated that arginine supplementation in BERK mice markedly reduced hemolysis (&gt; 60% reduction in plasma hemoglobin), increased NO generation, and decreased COX-2 expression and PGE2 levels. Since short-term arginine therapy improves PHT in SCD, we hypothesize that oral arginine therapy may impact GSH, a key erythrocyte anti-oxidant. Methods: Total erythrocyte GSH was analyzed using a sensitive liquid chromatography coupled to tandem mass spectrometric technique before and after arginine therapy at 0.1 mg/kg three times daily for 1 month, followed by 0.2 mg/kg three times daily for two more months, in 8 SCD patients already on stable hydroxyurea therapy. Results: Erythrocyte GSH levels increased significantly in SCD patients after arginine therapy (Mean±SEM: 1222±150 vs. 1593± 144mM, p=0.03; Figure 1). Conclusion: Arginine therapy increases erythrocyte GSH levels, which may decrease oxidative stress and hemolysis. Therapies that attenuate hemolysis and oxidative stress will likely benefit PHT in SCD. Figure 1: Arginine Therapy Figure 1:. Arginine Therapy

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