Clinical relevance of circulating midkine in ulcerative colitis.
BACKGROUND
Non-invasive biochemical markers are needed to support the diagnosis of ulcerative colitis (UC), an incurable disease of unknown pathology. Midkine is an angiogenic cytokine, chemotactic towards neutrophils and macrophages, and a T-regulatory cell suppressor.


METHODS
Serum midkine was measured immunoenzymatically in 93 UC patients and 108 healthy subjects, and evaluated with respect to disease status, endoscopic, inflammatory and angiogenic activity. The diagnostic value of midkine was compared to C-reactive protein (CRP) using receiver operating characteristics (ROC) analysis.


RESULTS
Midkine was higher (p<0.0001) in inactive (199 ng/L) and active UC (351 ng/L) compared with controls (93 ng/L), and reflected disease activity (r=0.427, p<0.001). Midkine was correlated with CRP, erythrocyte sedimentation rate (ESR), leukocytes, platelets, interleukin-6, paraoxonase-1, albumin, transferrin, iron, hemoglobin, and hematocrit. Midkine correlated with angiogenic factors: vascular endothelial growth factor-A and platelet-derived growth factor-BB. As a marker of UC, midkine showed a diagnostic accuracy of 85%, sensitivity of 72%, specificity of 82%, whereas CRP showed 83%, 65% and 91%, respectively. As a marker of active UC, midkine showed a diagnostic accuracy of 87%, sensitivity of 84%, specificity of 75%, whereas CRP showed 75%, 63% and 83%, respectively. Combined assessment of midkine and CRP improved sensitivity but substantially decreased specificity.


CONCLUSIONS
UC is associated with increased circulating midkine, which corresponds with clinical, endoscopic, inflammatory and angiogenic activity, and anemia. Performance of midkine as a marker of UC or active UC was comparable to that of CRP.
Krzystek-Korpacka
Malgorzata
M
Department of Medical Biochemistry, Wroclaw Medical University, Wroclaw, Poland. krzystek@bioch.am.wroc.pl
Neubauer
Katarzyna
K
Matusiewicz
Malgorzata
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000032:analysis; D003093:Colitis, Ulcerative / Q000175:diagnosis* / Q000000981:diagnostic imaging; D016207:Cytokines / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000078792:Midkine; D012372:ROC Curve; D011859:Radiography; D012680:Sensitivity and Specificity
D016207:Cytokines; D000078792:Midkine; D002097:C-Reactive Protein