Expression of human nephrin mRNA in diabetic nephropathy.
BACKGROUND
Diabetic nephropathy (DN) is associated with functional changes in the filtration barrier, and microalbuminuria is a strong predictor of the development of overt DN. Nephrin is a novel podocyte-specific protein which localizes at the slit diaphragm. This study examines the expression of nephrin mRNA in the kidneys of type 2 diabetics with DN.


METHODS
Renal tissues were obtained from 13 type 2 diabetics with DN. We also examined samples from five patients with minimal change nephrotic syndrome (MCNS) and five normal kidneys (normals) as control. The severity of DN was classified into two grades based on histopathological findings. DN grade 1 (DN1 = seven patients) presented mild mesangial expansion, and DN grade 2 (DN2 = six patients) moderate mesangial expansion. Nephrin mRNA was quantitated and localized by in situ hybridization.


RESULTS
Cells positive for nephrin mRNA were detected exclusively in glomerular epithelial cells. The percentage of cells positive for nephrin mRNA in DN2 was significantly lower than in MCNS and normal kidneys. Furthermore, there was an inverse correlation between the percentage of cells positive for nephrin mRNA and extent of proteinuria.


CONCLUSIONS
The low expression of nephrin mRNA may be closely linked to development and/or progression of proteinuria in human diabetic nephropathy.
Toyoda
Masao
M
Division of Nephrology and Metabolism, Department of Internal Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Japan.
Suzuki
Daisuke
D
Umezono
Tomoya
T
Uehara
Goro
G
Maruyama
Mayumi
M
Honma
Masashi
M
Sakai
Takako
T
Sakai
Hideto
H
D000328:Adult; D001707:Biopsy, Needle; D016022:Case-Control Studies; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000473:pathology; D003928:Diabetic Nephropathies / Q000235:genetics* / Q000473:pathology*; D018450:Disease Progression; D005260:Female; D005786:Gene Expression Regulation; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007677:Kidney Function Tests; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D011336:Probability; D011379:Prognosis; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis*; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric
D005819:Genetic Markers; D008565:Membrane Proteins; D011506:Proteins; D012333:RNA, Messenger; C113267:nephrin