Low nitric oxide level is implicated in sickle cell disease and its complications in Ghana

Abstract

Background

Nitric oxide (NO) plays a fundamental role in maintaining normal vasomotor tone. Recent clinical and experimental data suggest that NO may play a role in the pathogenesis and therapy of sickle cell disease (SCD). The aim of this study was to determine NO metabolites (NOx) in SCD patients at steady state and in vaso-occlusive crisis (VOC), as well as those with hemolytic clinical sub-phenotype that includes leg ulcers and priapism.

Methodology

This was a case–control cross-sectional study conducted on a total of 694 subjects including 148 comparison group HbAA, 208 HbSS SCD patients in steady state, 82 HbSC SCD patients in steady state, 156 HbSS SCD patients in VOC, 34 HbSC SCD patients in VOC, 34 HbSS SCD patients in post VOC, 21 HbSS SCD patients with leg ulcer and 11 HbSS SCD patients with priapism, with age ranging from 15 to 65 years. Laboratory diagnosis of SCD was done at the Sickle Cell Clinic of the Korle-Bu Teaching Hospital. Plasma nitric oxide metabolites were measured using Griess reagent system by ELISA method.

Results

Mean NOx of 59.66±0.75 µMol/L in the comparison group was significantly different from those in steady state (P=0.02). During VOC, there was a significant reduction in mean NOx levels to 6.08±0.81 µMol/L (P<0.001). Mean NOx levels were however, significantly higher (50.97±1.68 µMol/L) (P<0.001) in the immediate postcrisis period. The mean NOx levels in the leg ulcer (21.70±1.18 µMol/L) (P<0.001) and priapism (28.97±1.27 µMol/L) (P<0.001) patients were significantly low as compared to the SCD patients in the steady state and comparison group.

Conclusion

This study presents the first report on plasma NOx levels in SCD complication in Ghanaian SCD patients and confirms reduced plasma NOx levels in SCD patients in general.

Keywords:

• sickle cell disease
• nitric oxide metabolites
• vaso-occlusive crisis
• priapism
• leg ulcer
• ELISA

Acknowledgments

The authors are thankful to the Office of Research, Innovation and Development (ORID), University of Ghana and University of Ghana-Carnegie Next Generation of Academics in Africa Project for funding the research. The authors are also grateful to the staff and patients of the Center for Clinical Genetics (Sickle Cell Clinic) who took part in the study. Also, the authors would like to thank the volunteers who donated blood and consented to take part in the study as comparison group at the Accra Area Blood Center for National Blood Transfusion at the Korle-Bu Teaching Hospital, Accra, Ghana. The authors are also grateful to the following persons for their contributions: Frimpong Emmanuel, Gyan Ben, Kyei-Baafour, Eric Sey Fredericka, Bartholomew Dzudzor, Mubarak Abdul-Rahman, Agbozo William, Dankwah Boatemaa Gifty, Antwi-Boasiako Kate, Ekem Ivy, and Antwi Daniel Ansong. The research was funded by the ORID, University of Ghana and University of Ghana-Carnegie Next Generation of Academics in Africa.

Disclosure

The authors report no conflicts of interest in this work.