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Effects of N-acetylcysteine on dense cell formation in sickle cell disease
Betty S Pace1, Archil Shartava, Ardie Pack-Mabien
1Department of Molecular and Cell Biology, University of Texas at Dallas, 2601 Floyd Road, Mail Station FO 3.1, Richardson, TX 75083, USA. bpace@utdallas.edu
Insights
N-Acetylcysteine (NAC) effectively reduced dense red blood cells and vaso-occlusive episodes in sickle cell disease patients. This treatment shows promise for managing sickle cell complications.
Area of Science:
- Hematology
- Pharmacology
Background:
- Dense and irreversible sickle cells (ISCs) are implicated in sickle cell disease (SCD) vaso-occlusive episodes (VOEs).
- N-Acetylcysteine (NAC) demonstrates in vitro potential to inhibit dense cell and ISC formation and restore glutathione levels in sickle erythrocytes.
Purpose of the Study:
- To evaluate the efficacy of N-Acetylcysteine (NAC) in reducing dense cell formation, ISC formation, and VOEs in patients with sickle cell disease.
- To assess the safety and tolerability of NAC in SCD patients.
Main Methods:
- A phase II, double-blind, randomized clinical trial involving 21 SCD subjects with a history of at least two VOEs per year.
- Subjects were assigned to four treatment groups, including NAC at 2,400 mg/day.
- Measurements included percent dense cells, red cell glutathione levels, ISC counts, and VOE frequency.
Main Results:
- NAC at 2,400 mg/day significantly decreased percent dense cells (20.1% to 12.6%, P < 0.05) and increased red cell glutathione levels (292.8 to 576.7, P < 0.05).
- A significant reduction in VOEs was observed (0.03 to 0.006 episodes per person-days) with a relative risk of 0.39.
- NAC did not significantly decrease ISC numbers but showed a downward trend across tested doses.
Conclusions:
- N-Acetylcysteine (NAC) at 2,400 mg/day is effective in inhibiting dense cell formation and reducing vaso-occlusive episodes in sickle cell disease.
- NAC restored glutathione levels toward normal and was well-tolerated, warranting further investigation.
- A multicenter phase III trial is recommended to confirm long-term efficacy and safety of NAC for sickle cell disease management.
Abstract:
The extent to which dense and irreversible sickle cells (ISCs) contribute to vaso-occlusive episodes in sickle cell disease remains unclear. N-Acetylcysteine (NAC) inhibits dense cell and ISC formation in sickle erythrocytes in vitro and restores glutathione levels toward normal. A phase II double-blind randomized clinical trial was completed to determine the efficacy of NAC in decreasing dense cell and ISC formation, and vaso-occlusive episodes in sickle cell disease. Twenty-one subjects with a history of at least two vaso-occlusive episodes per year and 6% dense cells were enrolled. Four treatment groups were analyzed; NAC at a dose of 2,400 mg per day decreased the percent dense cells from 20.1 +/- 2.9 to 12.6 +/- 2.1 (P < 0.05) and increased red cell glutathione levels from 292.8 +/- 74.5 to 576.7 +/- 155.1 (P < 0.05). In addition, we observed a decrease in vaso-occlusive episodes from 0.03 to 0.006 episodes per person-days and a decreased in relative risk to R = 0.39. Although NAC did not significantly decrease the number of ISCs, there was a downward trend at all doses tested. In summary, NAC inhibited dense cell formation, restored glutathione levels toward normal, and decreased vaso-occlusive episodes at a well-tolerated dose of 2,400 mg per day. To determine the long-term efficacy and safety of NAC, a multicenter phase III clinical trial is required.
