Urinary procollagen III aminoterminal propeptide (PIIINP): a fibrotest for the nephrologist.
OBJECTIVE
Kidney biopsy (KB), to date the only tool for the evaluation of renal fibrosis, carries specific risks, and its relevance is limited by the small size of renal parenchyma assessed. Thus, a noninvasive alternative to KB is required. Collagen type III amino-terminal propeptide (PIIINP) is a degradation product of collagen type III, the increase of which may reflect an ongoing fibrotic process.


METHODS
In a prospective study including 199 patients with various stages of chronic kidney disease (CKD), the association between urinary PIIINP/creatinine ratio (UPIIINP/Cr), patients' characteristics, and renal fibrosis was assessed.


RESULTS
A total of 118 of the patients had UPIIINP/Cr measured simultaneously with the performance of a KB. In patients, median UPIIINP/Cr was 290 ng/mmol versus 93.7 ng/mmol in controls. In univariate analysis, UPIIINP/Cr was correlated with serum creatinine, estimated GFR, CKD stage, presence of coronary artery disease, and nephropathy type (glomerulonephritis versus other types). In multivariate analysis, only estimated GFR and nephropathy type were correlated with UPIIINP/Cr. UPIIINP/Cr was closely correlated with the extent of interstitial fibrosis in KB assessed using two different methods. Moreover, UPIIINP/Cr >800 ng/mmol had a negative predictive value of 94% to detect patients in whom KB will eventually prove "noninformative" (KB leading neither to a definite diagnosis of nephropathy nor to specific treatment).


CONCLUSIONS
UPIIINP/Cr is a promising fibro-test for the kidney and may alleviate the need for KB in some patients with CKD. Its predictive value for CKD progression deserves evaluation in prospective studies.
Ghoul
Balsam El
BE
Department of Nephrology, Université Paris Descartes, Hôpital Necker, Paris, France.
Squalli
Tarek
T
Servais
Aude
A
Elie
Caroline
C
Meas-Yedid
Vannary
V
Trivint
Christine
C
Vanmassenhove
Jill
J
Grünfeld
Jean-Pierre
JP
Olivo-Marin
Jean-Christophe
JC
Thervet
Eric
E
Noël
Laure-Hélène
LH
Prié
Dominique
D
Fakhouri
Fadi
F
D000328:Adult; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001706:Biopsy; D002908:Chronic Disease; D003404:Creatinine / Q000097:blood / Q000652:urine; D005260:Female; D005355:Fibrosis; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D007674:Kidney Diseases / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology / Q000652:urine; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000652:urine*; D011237:Predictive Value of Tests; D011347:Procollagen / Q000652:urine*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
D015415:Biomarkers; D010446:Peptide Fragments; D011347:Procollagen; C041876:procollagen Type III-N-terminal peptide; D003404:Creatinine