INCREASED SERUM MIDKINE LEVELS DURING HEMODIALYSIS USING HEPARIN IN CHRONIC-RENAL-FAILURE

The heparin-binding growth factor midkine (MH) has been implicated in neuron growth, angiogenesis, and inflammation, In this study, to eluci date the involvement of MK in the development of pathologies associate d with uremia, we examined the serum MK levels in patients receiving h emodialysis (HD) by a highly sensitive enzyme-linked immunoassay. Alth ough no significant difference was found between control serum and ser um before dialysis in HD patients, serum MK levels increased significa ntly at the early stage of HD sessions using heparin and gradually dec reased after dialysis. In normal controls, intravenous administration of heparin induced a similar sudden increase of MK, bat the subsequent decrease was also rapid. In an in vitro study, MK was released in tim e- and heparin-dose dependent manner from cultured vessels, but not fr om peripheral leukocytes, These results indicate that, in HD patients, MK is released mainly from endothelial cells immediately after admini stration of heparin during HD and disappears gradually from blood due to renal impairment. This phenomenon might affect some complications a ssociated with HD.