Estimation of RBC membrane and serum lipid composition in central Indian sickle cell disease population with and without pulmonary hypertension.

ABSTRACT

Aim: This study is designed to estimate and examine the relation between the levels of RBC membrane and serum lipids in central Indian sickle cell disease population with and without Pulmonary Hypertension .Methods: This study was carried out on central Indian sickle population at the Dept.of Biochemistry at MGM medical college & M.Y. hospital, Indore. From june 2011 to October 2012. Plasma Lipid concentrations were determined in 135 Sickle cell disease (SCD) patients, out of this 65 patients had sickle cell disease with Pulmonary Hypertension (SCD-PH) and 80 normal healthy matched individuals (controls). Study group comprises of both male and females in the age group of 18-56 years. Weight , height, waist hip ratio and blood pressure were recorded. All the blood samples were analyzed to determine the serum lipid concentration and RBC membrane lipid composition. Results: The body mass index and the systolic blood pressure of SCD with Pulmonary Hypertension (27.87 ± 4.68, 128.60 ± 22.49 mmHg) and without pulmonary hypertension (25.87 ± 4.68, 125.23 ± 15.89 mmHg ) were higher when compared with controls (24.67 ± 5.18, 119.15 ± 13.03 mmHg). The SCD with PH population (1.21 ± 0.07) and SCD without PH (1.09 ± 0.04) subjects showed significantly higher levels of RBC membrane cholesterol compared with controls (0.84 ±0.01). The trends of decreased serum cholesterol and normal high-density lipoprotein(HDL) levels in SCD patients were noted as compared with controls and these levels are statistically significant. The low-density lipoprotein cholesterol (LDL) was also significantly lower in SCD-PH and SCD when compared with control subjects. Interestingly serum Triglyceride levels are highly elevated in SCD-PH (208.43±.56.97) when compared with SCD (132.34±8.97) and controls (141.43±26.98). Elevated TGL concentrations are positively correlated with haemolytic markers (Lactate dehydrogenase and Total Bilirubin, (r=0.326 and r=0.468,P<0.001)). On a prospective screening of SCD population we found that around one third total population are with elevated tricuspid regurgetant jet velocity (TRJV) of 2.5m/s or higher. Conclusion: Our study data suggests that there is a relationship between RBC membrane and serum lipids in SCD population. Significant increase in RBC membrane cholesterol and decreased phospholipids in sickle cell disease play an important role in the fluidity and structural stability of the membrane and possibly in the Hemolysis and sickle shape of RBC. In pulmonary hypertension except the elevated levels of TGL remaining serum lipids are equal to the normal SCD population. This indicates the relation between TGL and vascular dysfunction in SCD.