Serum Magnesium Levels in Ghanaian Sickle Cell Disease Patients

Abstract

Background: Vaso-occlusive crisis (VOC), the hallmark of sickle cell disease (SCD) is responsible for the high rate of morbidity and mortality in SCD patients with sickling of the sickle haemoglobin (HbS) being the main cause. Reduction of the cellular concentration of HbS through prevention of erythrocyte dehydration has been proposed as a possible therapeutic strategy for VOC management with the K-Cl co-transporter being a major pathway for sickle cell dehydration and subsequent sickling. Recent studies have shown that red blood cell magnesium (Mg) content modulates K-Cl co-transport activity hence it plays a key role in sickle RBC dehydration and its subsequent pathogenesis in SCD. Magnesium is a nutrient and the fourth most abundant cation in the human body. Magnesium is an essential electrolyte which is involved in over 300 enzymatic reaction and physiological functions in the body. However, Mg status in patients is frequently undetected and it is described as the most under diagnosed electrolyte abnormality in current medical practice. There are other electrolyte abnormalities in SCD such as sodium, potassium and calcium. Data on serum magnesium levels in SCD patients available worldwide are very few and conflicting making it difficult to globally or regionally generalize the outcomes of such findings as a guide or tool in clinical practice. To date, there is no data on serum magnesium levels in Ghanaian SCD patients. There is therefore, the need to gather data in that regard. Aim: The aim of this study was to assess the levels of serum magnesium in Ghanaian SCD patients in steady state and VOC. Methodology: The study is a cross sectional study with a total of 371 subjects. This was made up of 80 HbAA apparently healthy individuals recruited from the Accra Area Blood Centre for National blood donation, 97 HbSS SCD patients in steady state, 75 HbSS SCD patients in VOC, 56 HbSC SCD patients in steady state and 63 HbSC SCD patients in VOC recruited from the Centre for clinical Genetics at Korle Bu Teaching Hospital. Haematological profile of samples taken was measured using a lab system multiskan MS analyzer (Bioscience LTD, UK). Serum magnesium and calcium levels were determined using an Atomic Absorption Spectrophotometer (Variant 240FS manufactured by VARIAN Australia Pty Ltd). Serum sodium and potassium levels were also measured using the Sherwood Flame Photometer (Model 420). Nitric oxide level in plasma was also measured by Griess Reagent System (ELISA Kit, Promega). Data collected was entered into SPSS software student version 20.0 and used for analyses. Results: The results from this study shows that, the mean serum Mg levels were significantly lower in SCD patients than in controls p < 0.001, however, the levels between steady state and VOC in SCD patients were not significantly different p = 0.24. The mean serum Ca level in SCD patients was significantly lower as compared with individuals with HbAA p < 0.001. Serum Na and K levels were significantly lower in SCD patients in steady state as compared to apparently healthy HbAA individual’s p < 0.001, with a further decrease during VOC p < 0.02. Serum NO levels were significantly high in HbAA individuals than in SCD patients in steady state and declined during the VOC in both the HbSS and HbSC patients’ p < 0.001. Furthermore, this study showed a weak positive correlation between serum magnesium and plasma NO levels in the HbSS and HbSC of the SCD patients in steady state r= 0.112 and r= 0.66 respectively. However there was a negative correlation between magnesium and NO levels in both HbSS and HbSC in VOC r = -0.905 and r = -1.802 repectively. Conclusion The mean serum Mg and Ca levels were significantly lower in SCD patients regardless of their clinical state as compared with HbAA individuals. Serum Na and K levels were decreased in SCD patients as compared to HbAA individuals and a further decrease during VOC. Nitric oxide levels were significantly higher in Hb individuals than in SCD patients during the steady state regardless of the genotype. Nitric oxide levels were further reduced during VOC. This study revealed a weak positive association between serum Mg and NO levels in the steady states in SCD. Generally, electrolyte levels were low in SCD patients as compared to HbAA individuals. This study confirmed electrolyte abnormality in SCD patients.