Faecal M2-pyruvate kinase: a novel, noninvasive marker of ileal pouch inflammation.
BACKGROUND
Dimeric M2-pyruvate kinase (dM2-PK) is overexpressed in tumour cells with rapid cell turnover. Its concentrations correlate well with the staging and metastatic capability of the tumour cells. We investigated the use of faecal dM2-PK as a noninvasive marker of pouch inflammation (pouchitis) in patients having undergone restorative proctocolectomy.


METHODS
Stool samples were obtained from 46 patients with ulcerative colitis (UC) and eight with familial adenomatous polyposis. Pouchitis was defined using the objective pouchitis score (OPS) and the pouch disease activity index. Faecal dM2-PK was measured using a quantitative sandwich-type enzyme immunoassay (ScheBo Biotech UK) and the results compared with reciprocal faecal calprotectin concentrations.


RESULTS
Using the OPS, 6 of the 46 patients with UC had pouchitis and prepouch ileitis, 13 had UC pouchitis alone, and 27 had a non-inflamed UC pouch. One patient with familial adenomatous polyposis had pouchitis and prepouch ileitis and 7 had an non inflamed pouch. Respective median dM2-PK values (U/ml) for these five groups were 49.5 (4.5-110), 12 (1-192.3), 2.2 (0.1-95.2), 19.5 and 1 (0.1-3). Statistically significant differences were noted between inflamed and non inflamed pouches (P<0.0001). dM2-PK correlated significantly with the OPS, pouch disease activity index, endoscopic appearances, acute histological and neutrophil scores (<0.0001). The receiver operating characteristic analysis demonstrated a sensitivity and specificity of 80 and 70.6%, respectively. dM2-PK and faecal calprotectin concentrations correlated closely (r=0.87, P<0.0001).


CONCLUSIONS
This study demonstrates that faecal dM2-PK is a sensitive marker of pouch inflammation and that its concentration directly correlates with the objective markers of pouchitis severity.
Johnson
Matt W
MW
Department of Surgery, St Mark's Hospital, Harrow, Middlesex, UK. mattcat1_@hotmail.com
Maestranzi
Susan
S
Duffy
Audrey M
AM
Dewar
David H
DH
Ciclitira
Paul J
PJ
Sherwood
Roy A
RA
Nicholls
John R
JR
D011125:Adenomatous Polyposis Coli / Q000601:surgery; D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D004796:Clinical Enzyme Tests / Q000379:methods; D003093:Colitis, Ulcerative / Q000601:surgery; D003113:Colonoscopy; D005243:Feces / Q000737:chemistry*; D005260:Female; D006801:Humans; D039841:Leukocyte L1 Antigen Complex / Q000032:analysis; D008297:Male; D008875:Middle Aged; D019449:Pouchitis / Q000175:diagnosis* / Q000473:pathology; D016737:Proctocolectomy, Restorative; D011770:Pyruvate Kinase / Q000378:metabolism*; D012720:Severity of Illness Index
D015415:Biomarkers; D039841:Leukocyte L1 Antigen Complex; D011770:Pyruvate Kinase