Serum and Urine Sialic Acid in Sickle Cell Nephropathy

Background: Renal manifestations of sickle cell anaemia range from functional abnormalities to gross anatomic alterations of the kidneys. As people with sickle cell anaemia (SCA) grow older, the kidneys may progress to end-stage renal disease if proper monitoring of renal function is not done.

Aim: The aim of this study is to determine the serum and urine sialic acid levels in SCA patients and correlate with plasma urea and creatinine.

Methods: Venous blood and fresh urine samples were collected from participants and the standard Ehrlich method was used in the analysis of serum and urine sialic acid. The modified Jaffe method was used in the analysis of plasma and urine creatinine and the Urease Berthelot method for plasma urea.

Results: A total of 98 respondents participated in the study consisting of 68 SCA patients and 30 control subjects. The mean age was 28.35 ± 0.42 years for SCA subjects and 33.12 ± 1.14 years for control subjects and most of the SCA subjects were females (M:F = 1 : 1.6). The serum sialic acid (SSA) level was 1.88 ± 0.96 mmol/L for SCA subjects and 1.93 ± 0.67 mmol/L for controls and it was found to be non-significantly (P =0.81) higher in SCA subjects with microalbuminuria (1.89 ± 0.07 mmol/L) than in those with normoalbuminuria (1.86 ± 0.10 mmol/L). However, the mean urine sialic acid creatinine ratio (USACR) was higher in SCA subjects (169.39 ± 13.59 mmol/mol) than in the control subjects (60.52 ± 3.39 mmol/mol) and this was statistically significant (P< 0.05). Also, the mean USACR was significantly (P < 0.05) higher in SCA subjects with microalbuminuria than in those with normoalbuminuria.

Conclusion: Serum sialic acid (SSA) is low while USACR is high in SCA patients. Hence, monitoring of serum and urine sialic acid in patients with sickle cell anaemia will be important in detecting early onset of sickle cell nephropathy.