Serum fibroblast growth factor-2 and fibroblast growth factor-9 levels in bipolar disorder: Potential biomarkers for mood episodes.

BACKGROUND

The aim of this study was to compare serum levels of Fibroblast Growth Factor-2 (FGF-2) and Fibroblast Growth Factor-9 (FGF-9) between patients with Bipolar Disorder (BD) and healthy controls (HC), and to evaluate whether these molecules could serve as potential biomarkers for mood episodes (manic/depressive).

METHODS

A total of 121 patients diagnosed with BD according to DSM-5 criteria (47 euthymic, 37 manic, 37 depressive) and 67 healthy controls were included. Peripheral venous blood samples were obtained from all participants after 8-12 h of fasting to measure serum FGF-2 and FGF-9 levels.

RESULTS

FGF-2 levels were significantly lower in the BD episode (manic+depressive) group compared to both the euthymic BD and healthy control groups, while no significant difference was found between the euthymic BD and control groups. FGF-9 levels were significantly lower in the episode group compared to the euthymic group, though the difference from healthy controls was not significant. FGF-2 and FGF-9 levels were similar between manic and depressive patients. Based on ROC curve analysis, the cut-off point for FGF-2 was ≤43.10 pg/mL (sensitivity 79.7%, specificity 44.7%, AUC = 0.681), and for FGF-9 was ≤60.50 pg/mL (sensitivity 85.1%, specificity 48.9%, AUC = 0.653).

CONCLUSION

These findings suggest that FGF-2 and FGF-9 may be associated with mood episode status in BD. Given the observed cut-off values and modest discriminative performance, these molecules may represent preliminary biomarker candidates, although further longitudinal validation is required.