CKDdb-logoCKDdb - Study ID Exp17021608

PubMed ID17021608
AuthorsZhou H, Pisitkun T, Aponte A, Yuen PS, Hoffert JD, Yasuda H, Hu X, Chawla L, Shen RF, Knepper MA, Star RA.
TitleExosomal Fetuin-A identified by proteomics: a novel urinary biomarker for detecting acute kidney injury.
JournalKidney Int. 2006 Nov;70(10):1847-57. Epub 2006 Oct 4.
AbstractUrinary exosomes containing apical membrane and intracellular fluid are normally secreted into the urine from all nephron segments, and may carry protein markers of renal dysfunction and structural injury. We aimed to discover biomarkers in urinary exosomes to detect acute kidney injury (AKI), which has a high mortality and morbidity. Animals were injected with cisplatin. Urinary exosomes were isolated by differential centrifugation. Protein changes were evaluated by two-dimensional difference in gel electrophoresis and changed proteins were identified by mass spectrometry. The identified candidate biomarkers were validated by Western blotting in individual urine samples from rats subjected to cisplatin injection; bilateral ischemia and reperfusion (I/R); volume depletion; and intensive care unit (ICU) patients with and without AKI. We identified 18 proteins that were increased and nine proteins that were decreased 8 h after cisplatin injection. Most of the candidates could not be validated by Western blotting. However, exosomal Fetuin-A increased 52.5-fold at day 2 (1 day before serum creatinine increase and tubule damage) and remained elevated 51.5-fold at day 5 (peak renal injury) after cisplatin injection. By immunoelectron microscopy and elution studies, Fetuin-A was located inside urinary exosomes. Urinary Fetuin-A was increased 31.6-fold in the early phase (2-8 h) of I/R, but not in prerenal azotemia. Urinary exosomal Fetuin-A also increased in three ICU patients with AKI compared to the patients without AKI. We conclude that (1) proteomic analysis of urinary exosomes can provide biomarker candidates for the diagnosis of AKI and (2) urinary Fetuin-A might be a predictive biomarker of structural renal injury.

Sample characteristics

SpeciesTissue / SourceCompartmentDiseaseNDetection methodSample
Rattus norvegicusurineexosomeAKI12MALDI-TOF-TOFDem17021608

Sample description and preparation

Disease (case)AKI
Disease (control)healthy
Disease inductioncisplatin, 6 mg/kg b. w.
Digestin-gel, trypsin

Molecule list

Molecule IDextExternal IDGeneNameRegulation (case/control)Scores
A0146 HSP7C_RATHspa8, Hsc70, Hsc73Heat shock cognate 71 kDa protein
A0397 D4A133Atp6v1aProtein Atp6v1a
A1581XALBU_RATAlbSerum albumin ( Precursor)
A1597 SAMP_RATApcs, Ptx2, SapSerum amyloid P-component
A3615 ENOA_RATEno1, Eno-1Alpha-enolase
A4443 CLIC1_RATClic1Chloride intracellular channel protein 1
A4548 ACTB_RATActbActin
A4575XANXA4_RATAnxa4, Anx4Annexin A4
A4576 ANXA5_RATAnxa5, Anx5Annexin A5
A5802 Q5I0L0Amy1a, Amy1Alpha-amylase
A5805XAMYP_RATAmy2, Amy2a3, Amy2-3Pancreatic alpha-amylase
A5925 BGLR_RATGusb, GusBeta-glucuronidase ( Precursor)
A6663 GSHB_RATGssGlutathione synthetase
A6992 MDHC_RATMdh1, MdhMalate dehydrogenase
A7681 RGN_RATRgn, Smp30Regucalcin

Compile date 08-10-2018© iMODE-CKD consortium