Quantification and regulation of adipsin in human cerebrospinal fluid (CSF)

SummaryContext Data on quantification and regulation of adipsin in human cerebrospinal fluid (CSF) are sparse, and the physiological role of adipsin as an adipokine crossing the blood–brain barrier (BBB) is uncertain. Objectives This study quantified adipsin concentrations in paired serum and CSF samples of patients undergoing neurological evaluation and spinal puncture. Design A total of 270 consecutive patients with specified neurological diagnosis were included in this study without prior selection. Main outcome measures Adipsin serum and CSF concentrations were measured by ELISA. A variety of serum and CSF routine parameters were measured by standard procedures. Anthropometric data, medication and patient history were available. Results Adipsin concentrations ranged between 467 and 5148 ng/ml in serum and between 4·2 and 133·5 ng/ml in CSF. Serum adipsin concentrations were correlated positively with respective CSF concentrations and were approximately 40-fold higher when compared to CSF. The mean CSF/serum ratio for adipsin was 27 ± 22 × 10−3. Serum and CSF adipsin levels were independent of gender and significantly higher in overweight/obese individuals. Serum and CSF adipsin levels correlated significantly with age and were higher in patients suffering from diabetes mellitus or hypertension. CSF adipsin concentrations showed a significant correlation with markers of inflammation in CSF, but not with CSF total cell count or the presence of oligoclonal bands. Patients suffering from infectious diseases had higher CSF levels of adipsin than multiple sclerosis patients. Conclusions Adipsin is present in human CSF under pathophysiological conditions. The positive correlation between serum and CSF concentrations, the positive correlation between the CSF/serum ratios for adipsin and total protein and the lack of association with CSF cell count argue against an autochthonous production in the central nervous system. In contrast, the present data argue for a significant BBB permeability to adipsin.