Concentrations and regulation of adipokines resistin and progranulin in human cerebrospinal fluid

Blood-CSF patency of the adipokines resistin and progranulin is largely unknown. The aim of this study was to quantify resistin and progranulin in human cerebrospinal fluid and to investigate their physiological regulation in the context of neurological diseases. Paired samples of cerebrospinal fluid (CSF) and serum (S) were collected from 270 patients (110 men, 160 women) with different neurological diseases. Concentrations of resistin and progranulin were measured by ELISA in S and CSF. Anthropometric parameters and routine laboratory parameters (S and CSF) were analyzed. We were able to quantify progranulin in all S and CSF samples. Resistin was detectable in all S samples whereas its concentration in CSF samples exceeded the lower limit of detection (31.2 pg/ml) in only 112 individuals. Progranulin concentrations in S and CSF were not influenced by BMI, gender and diabetes mellitus. S-progranulin was positively correlated with S-resistin and LDL cholesterol. S-resistin was significantly elevated in females and was positively correlated with systemic markers of inflammation, LDL cholesterol and immunoglobulins in CSF (CSF-Ig). CSF-resistin was positively correlated with CSF protein/Ig ratio and with the degree of blood-CSF dysfunction whereas there was no significant correlation with CSF cell count. Furthermore, positive correlations of CSF-progranulin with inflammatory parameters and with the degree of blood-CSF dysfunction were observed. In contrast to S-progranulin, the mean of S-resistin was significantly increased in inflammatory compared to non-inflammatory neurological diseases. The adipokines resistin and progranulin exist in human CSF in significant quantity. Resistin appears to be a marker of systemic inflammation. It is increased in serum of patients with inflammatory neurological diseases whereas in CSF it indicates the degree of blood-CSF dysfunction. Progranulin is correlated with all inflammation markers analysed in CSF but only to a smaller extent with markers of systemic inflammation.