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Published on: November 5, 2019
L-glutamine for sickle cell disease: more than reducing redox
Firas Jafri1, Gyuhee Seong2, Tim Jang2
1Division of Hematology and Oncology, Department of Medicine, SUNY Downstate Health Sciences University, Brooklyn, NY, USA.
Insights
L-glutamine helps reduce vaso-occlusive crises (VOC) in sickle cell disease (SCD) by addressing oxidative stress. Further research into its extra-erythrocytic functions may improve treatment efficacy.
Area of Science:
- Biochemistry
- Hematology
- Pharmacology
Background:
- Oxidative stress significantly contributes to sickle cell disease (SCD) pathophysiology, leading to hemolysis and vaso-occlusive crises (VOC).
- Sickle red blood cells exhibit higher oxidative stress and a lower NADH:NAD+ ratio, negatively impacting blood flow.
- L-glutamine, an amino acid, plays a role in synthesizing antioxidants and cofactors like glutathione and NAD(H)/NADP(H).
Purpose of the Study:
- To investigate the therapeutic potential of L-glutamine in reducing VOC in SCD patients.
- To understand the impact of L-glutamine on the redox environment within sickle erythrocytes.
- To clarify the mechanisms by which L-glutamine alleviates VOC in SCD.
Main Methods:
- Summary of Phase 3 study results leading to L-glutamine's FDA approval for SCD.
- Discussion of proposed mechanisms of action for L-glutamine in SCD.
- Examination of L-glutamine's role in general health and its extra-erythrocytic functions.
Main Results:
- L-glutamine was approved by the US FDA for treating SCD, indicating clinical efficacy in reducing VOC.
- The precise impact of L-glutamine on the redox state of sickle erythrocytes requires further elucidation.
- The exact mechanisms through which L-glutamine confers its benefits in SCD are not fully understood.
Conclusions:
- L-glutamine is an approved treatment for SCD, demonstrating a reduction in vaso-occlusive crises.
- Understanding L-glutamine's effects on the redox environment and extra-erythrocytic functions is crucial for optimizing its use.
- Further research may lead to enhanced L-glutamine formulations for improved therapeutic outcomes in SCD.
Abstract:
Oxidative stress is a major contributor to the pathophysiology of sickle cell disease (SCD) including hemolysis and vaso-occlusive crisis (VOC). L-glutamine is a conditionally essential amino acid with important roles, including the synthesis of antioxidants, such as reduced glutathione and the cofactors NAD(H) and NADP(H), as well as nitric oxide. Given the increased levels of oxidative stress and lower (NADH):(NAD + + NADH) ratio in sickle erythrocytes that adversely affects the blood rheology compared to normal red blood cells, L-glutamine was investigated for its therapeutic potential to reduce VOC. While L-glutamine was approved by the United States (US) Food and Drug Administration to treat SCD, its impact on the redox environment in sickle erythrocytes is not fully understood. The mechanism through which L-glutamine reduces VOC in SCD is also not clear. In this paper, we will summarize the results of the Phase 3 study that led to the approval of L-glutamine for treating SCD and discuss its assumed mechanisms of action. We will examine the role of L-glutamine in health and propose how the extra-erythrocytic functions of L-glutamine might contribute to its beneficial effects in SCD. Further research into the role of L-glutamine on extra-erythrocyte functions might help the development of an improved formulation with more efficacy.
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