Serum levels of malondialdehyde,vitamin C and E in idiopathic nephrotic syndrome: a meta-analysis

It is well documented that oxidative stress is involved in the pathogenesis of idiopathic nephrotic syndrome (INS). Malondialdehyde (MDA) is a measurement of lipid oxidation; vitamin C and E are important components of antioxidants. However, the association between MDA, vitamin C or E levels and INS remains elusive. A meta-analysis was performed to investigate the alteration of serum levels of MDA, vitamin C and E in INS compared with controls. Eight studies were included in our meta-analysis according to predefined criteria. Active INS patients demonstrated significantly higher level of serum MDA (SMD: 2.13, 95% CI: 1.511 to 2.749, p?10^?4), markedly lower levels of serum vitamin C (SMD: ?1.449, 95% CI: ?2.616 to ?0.281, p?=?0.015) and E (SMD: ?1.45, 95% CI: ?2.544 to ?0.356, p?=?0.009) compared with those in controls. Active steroid-sensitive nephrotic syndrome (SSNS) patients showed comparable levels of serum vitamin C and E to those in controls. INS subjects in the remission stage demonstrated significantly higher level of serum MDA (SMD: 1.028, 95% CI: 0.438 to 1.617, p?10^?4), markedly lower level of serum vitamin C (SMD: ?2.235, 95% CI: ?3.048 to ?1.421, p?10⁴) and similar level of serum vitamin E compared with those in controls. No significant publication bias was observed. In conclusion, the disorder of MDA and vitamin C persists in the remission stage of INS. It seems that the serum levels of vitamin C and E is associated with the responsiveness of INS to steroids. However, more studies should be performed in the future.