Evaluation of Soluble Intercellular Adhesion Molecule-1 and Soluble P Selection in Sickle Cell Disease

Introduction

Sickle Cell Diseases (SCD) affects millions of people throughout the world and particularly common among those whose ancestors came from Sub-Saharan Africa, Spanish – Speaking regions in the western Hemisphere (South America, The Caribbean and central Africa) Saudi Arabia, India and Mediterranean countries such as Turkey, Greece and Italy [1]. Sickle Cell disease is of major public health concern. From 1989 through 1993, an average of 75,000, hospitalisation due to the sickle cell disease occurred in the United States, costing approximately and 475 million dollars [2]. Sickle cell related death among black African-American children younger than 4years of age fell by 42% from 1999 through 2002. This drop coincided with the introduction in 2000 of a vaccine that protects against invasive pneumococcal disease [3].

In 2006 the World Health Organisation (WHO) pronounced Nigeria as the country with the highest number of sufferer of sickle cell anaemia in the world .The global health watch dog put the annual number of sickle cell anaemia suffers in African at about 200,000noting that Nigerian accounts for 150,000 sickle cell anaemia every year [4]. In most countries, where sickle cell anaemia is a major public health concern, its management has remained inadequate, national control programmes do not exist. The basic facilities to manage the patients are usually absent. Systematic screening is not a common practice and the diagnoses is usually made when a patient present with a severe complication .Simple cheap and very cost effective procedure such as the use of penicillin to prevent infections are not widely available in many countries. The governing bodies of WHO have adopted two resolutions on haemoglobin disorder. The resolution on sickle cell disease from the 59th world health assembly in May 2006 and the resolution on thalassemia from the 118th meeting of the WHO executive board call upon affected countries and the secretariat of WHO to strengthen their response to these conditions. In addition a resolution on the prevention and management of birth defects, including sickle cell disease and thalassemia were adopted by the 63th world health assembly in May 2010 [5].

In a resolution of World Health Assembly (WHA) 57. 13 the Health Assembly urged member states to mobilizes resources for action on genomics and in May 2005 the executive Board took note of the secretariat’s report on control of genetics disease subsequently, the Assembly of the African Union at its fifth ordinary session supported the inclusion of sickle cell anaemia in the list of public health priorities [6].

The major pathology of sickle cell diseases is haemolysis and vaso occlusion, endothelial activation has a major role in the pathophysiology of sickle cell diseases Hoover, et al. [7], it is now proved that deformed sickle red cells and reticulocytes adhere abnormally to the vascular endothelium [8]. Leucocytes also adhere to the endothelial forming heterocellular aggregates which further contribute to the occlusion of small and large blood vessels [9]. The binding of sickle cells, reticulocytes and leucocytes to the endothelial membrane was mediated by endothelial adhesion molecules, which are expressed after cytokine stimulation during endothelial activation [10, 11].

Endothelial adhesion molecules such as soluble Intercellular adhesion molecules 1(sICAM-1), soluble Vascular cell Adhesion Molecule(sVCAM-1), P Selection etc, have shown increased levels in the blood of sickle cell patients Conran, et al. [12]. In this regard d Soluble P Selection, Soluble ICAM has been proposed to be useful maker in accessing sickle cell patients.

The aim of the study is to investigate the link between steady and crisis state in sickle cell disease and some adhesion molecules.

Results

Eighty (80) subjects were used for this research, 48 were Female while 32 were males. 40 SS patients were attending UNTH Ituku- Ozzala Enugu, they were divided into 20 at crisis state and 20 at steady state. AA and AS control subjects, 20 each were used. They have average age between 2- 45 years. Soluble P Selection and soluble ICAM-1 was assayed using ELISA on DAR 800 Microwell plate Reader. The statistical variables obtained for the research is as follow:

Table 1 the mean plasma level of P selection in SS at crisis state were (12.51±3.42ng/ml), SS at steady state (13.33±3.52ng/ml), AS control (14.49±2.43ng/ml) AA control (14.36±3.83ng/ml). Table 2 the mean plasma level of P selection of SS at Crisis state, SS at steady state, AS controls and AA controls were compared with each other using Dunns multiple comparison test but there was no statistical significant difference (P>0.05). Table 3 the mean Plasma level of sICAM-1 of SS at crisis state was 129.8±13.6Pg/ml, SS at steady state 122.9±21.6Pg/ml while that of the AS control and AA controls were 122.0±27.9pg/ml and 118.1±31.3pg/ ml respectively. While in table 4.5b The mean plasma level of sICAM-1of SS at Crisis state, SS at steady state, AS controls and AA controls were compared with each other using Dunns multiple comparison test but there was no statistical significant difference (P>0.05). Figure 1 Graphical representation of Adhesion molecules which include soluble P selection and soluble ICAM-1using box and whiskers plots on HbSS at crisis, HbSS at Steady, HbAS control and HbAA control.

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Discussion

The morbidity of Sickle cell diseases varies with genotype as well as within the same genotype, some of the established predictors of this phenotypic heterogeneity are the levels of HbF present, presence of α-thalassaemia and the β-haplotype associated with the Hbs gene [11].

In 2006, the world Health organisation pronounced Nigeria as the country with the highest number of sufferer of sickle cell anaemia in the world. In a resolution, world Health Assembly urge member states to mobilizes resources for action on genomics, the executive board took note of the secretariat report on control of genetics disease and subsequently supported the inclusion of sickle cell anaemia in the list of public health properties (WHA 57.13) Our data indicate a novel mechanism for sickle cell adherence to endothelial cell causing vaso occlusion, the soluble ICAM-1 plasma level at crisis and steady state were (123.4±13.68ng/ml) and (122.9±21.65ng/ml) respectively, and when compared there was no significant difference (p>0.05).also with both AA and AS, there were no statistical significant difference at (p>0.05). Equally there was no statistical significant difference (P>0.05) in the mean value of P selection of HbSS at crisis state and HbSS at steady state and also in HbAA and HbAS. This work goes contrary with the work of Conran et al which stated that ‘’Plasma sICAM-1 levels were significantly increased in steady sickle cell disease patients compared to normal individual (285±20ng/ml vs 202±16ng/ml respectively ( p<0.002) [12]. Kato, et al. [13] showed increased plasma levels of sVCAM-1, E-selection and P-selection in the patients compared with African American healthy individuals, while no difference was found regarding the sICAM-1 level, our plasma soluble ICAM-1 in this work also agree with Kato et al work.

The work of Kanavaki, et al. [14] also goes contrally with this work hence there was significant increase in both sICAM-1 and P selection. The decrease in sICAM-1 and P selection in this work might be as a results of some of the patients being on hydroxyurea which is one of the most successfully used therapy for SCD that function primarily by elevating foetal haemoglobin levels in patients, one of the theory gaining increasing support postulate that, hydroxyurea may produce nitric oxide in the plasma of SCD following oxidation by haem groups. Nitric oxide has been shown to inhibit both sICAM-1 and VCAM-1 adhesion molecules on the surface of the endothelial cells [12].

Conclusion

In conclusion, this study shows that, there was no statistical significant difference in sICAM-1, P selection at steady and crisis state.