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Urinary Excretion of Kidney Aquaporins as Possible Biomarker of Diabetic Nephropathy
Author(s) -
Procino Giuseppe,
Rossi Luigi,
Nicoletti Maria Celeste,
Carmosino Monica,
Di Franco Antonella,
Indrio Francesca,
Lella Rosa,
Laviola Luigi,
Gesualdo Loreto,
Svelto Maria
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.968.20
Subject(s) - diabetic nephropathy , urine , blot , urinary system , exosome , kidney , biomarker , aquaporin 2 , excretion , aquaporin , renal function , medicine , nephropathy , endocrinology , urology , chemistry , diabetes mellitus , pathology , microvesicles , biochemistry , water channel , microrna , mechanical engineering , engineering , inlet , gene
Background Diabetic nephropathy (DN) is is classified into four hierarchical glomerular lesions on the basis of histological analysis of kidney biopsies. This is clearly a highly invasive diagnostic approach numerous studies have been conducted to identify a non‐invasive biomarker of the disease, but none of these is considered to be sufficiently specific and sensitive Experimental evidences showed that the water channel aquaporins (AQP), expressed at the plasma membrane of epithelial cells lining in the kidney tubule, are often dysregulated during DN. Interestingly, apical membrane protein are excreted in the urinary space as nano‐scale exosome vesicles, to an extent proportional to their amount expressed at the plasma membrane, thus allowing their quantitation in urine samples. Methods In this work we compared excretion of AQP5 and AQP2 (uAQP5 and uAQP2) in the urine of 35 diabetic patients: 12 with histological diagnosis of DN, 12 with with normal renal function and normoalbuminuric (DM) and 11 with non‐diabetic nephropathy (NDN). Both proteins were quantified by ELISA method on urine samples and the results were validated by Western blotting analysis on the exosome fraction isolated by ultracentrifugation. Results BothELISA and Western blotting analysis independently showed that uAQP5 was three‐ to fourfold higher in DN patients (7458 ± 2576, p <0.05) compared to the other two groups (D 847,2 ± 70,51; NDN1882 ± 215). uAQP5 was not statistically different between D and NDN patients. Strikingly, uAQP5 dramatically increased in parallel with the clinical severity of DN. The same analysis showed comparable results for uAQP2. Conclusions Our data showed, for the first time, that uAQP5 and uAQP2 dramatically and specifically increase in patients with DN and positively correlate with the histological class of DN. Taken together these data suggest a possible role of AQP5 and AQP2 as novel non‐invasive biomarkers to help diagnosing DN and classifying its histological stage. Support or Funding Information Non U.S.