An explorative analysis of secretory receptor for advanced glycation endproducts in primary focal segmental glomerulosclerosis.

BACKGROUND

Despite remarkable medical progress, the main pathogenetic mechanisms of focal segmental glomerulosclerosis (FSGS) have not been fully delineated and its prognosis is poor at present. Recently, it was revealed that the receptor for advanced glycation endproducts (RAGE) was highly expressed at the base of podocytes with an up-regulation mainly in diabetic nephropathy. However, there is no report about the association between glomerulonephritis and RAGE. The aims of the current study were to explore the relationships between several clinical parameters and circulating soluble RAGE in primary FSGS and compare serum levels in primary FSGS with immunoglobulin A nephropathy (IgAN) and controls.

METHODS

A total of 35 subjects aged >18 years were enrolled. Thirty-five subjects consisted of three groups: primary FSGS (N = 15), IgAN (N = 10), and normal controls (N = 10). Laboratory measurements of serum carboxymethyl-lysin (CML), soluble RAGE (sRAGE), and endogenous secretory RAGE (esRAGE) were performed.

RESULTS

Serum esRAGE level in the FSGS group was higher than that in the IgAN group (0.55 ± 0.32 ng/mL vs. 0.27 ± 0.11 ng/mL, p = 0.013). There was no statistical difference between sRAGE and CML among the three groups. Within the FSGS group, esRAGE, but not sRAGE, was positively correlated with 24-h urinary protein (r = 0.553, p = 0.033) and negatively correlated with body mass index (r = -0.623, p = 0.013). In stepwise multiple regression analysis, body mass index and 24-h urinary protein were significant contributors to esRAGE within the FSGS group.

CONCLUSION

This study showed that only the serum level of esRAGE, not sRAGE, was higher in the FSGS group than in the IgAN and control groups. The amount of 24-h proteinuria was also related to the serum level of esRAGE in the FSGS group.