Correlations of Cerebrospinal Fluid/Plasma Fibroblast Growth Factor 21 Ratio with Metabolic Parameters in Chinese Individuals of Normal Weight.

Background: Fibroblast growth factor 21 (FGF21) is an important metabolic regulator that has multiple beneficial effects on glucose homeostasis and lipid metabolism. Although circulating levels of FGF21 are mainly derived from liver, FGF21 is also found in other tissues and fluids including the cerebrospinal fluid (CSF). The aim of the present study was to investigate the relationships of CSF and/or plasma FGF21 levels with metabolic parameters in a normal-weight Chinese population.

Methods: Forty-five subjects (22 males and 23 females) were recruited from a patient population undergoing surgery for lower extremity injuries due to ligament damage or bone fractures below the knee in the Beijing Jishuitan Hospital. The levels of FGF21 in CSF and plasma were determined by radioimmunoassay and enzyme-linked immunosorbent assay, respectively.

Results: No significant differences were detected in the levels of FGF21 in CSF and plasma between males (CSF: 158.01 ± 12.10 pg/mL; plasma: 206.19 ± 7.22 pg/mL) and females (CSF: 159.27 ± 17.85 pg/mL; plasma: 203.10 ± 7.53 pg/mL). The level of FGF21 in CSF was about 75% of that in plasma. The FGF21 level in CSF was positively correlated with triglyceride level, whereas plasma FGF21 level was negatively correlated with alanine aminotransferase in women but not in men. The CSF/plasma FGF21 ratio was positively correlated with CSF FGF21 in both genders and with peripheral glucose, triglyceride, and gamma-glutamyl transferase levels in female Chinese patients.

Conclusions: These results have important implications regarding the potential central actions of FGF21.