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.


CONCLUSIONS
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.
Division of Nephrology, Department of Internal Medicine, Pusan National University School of Medicine, 179 Gudeok-ro, Seo-gu, Busan 602-739, Republic of Korea.
Harin
H
Rhee
Sang Heon
SH
Song
Ihm Soo
IS
Kwak
Il Young
IY
Kim
Eun Young
EY
Seong
Dong Won
DW
Lee
Soo Bong
SB
Lee
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D005260:Female; D005922:Glomerulonephritis, IGA / Q000097:blood; D005923:Glomerulosclerosis, Focal Segmental / Q000097:blood*; D006801:Humans; D008239:Lysine / Q000031:analogs & derivatives / Q000097:blood; D008297:Male; D008875:Middle Aged; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic / Q000097:blood*; D012044:Regression Analysis; D055815:Young Adult
D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic; C048496:N(6)-carboxymethyllysine; D008239:Lysine