Significantly higher peripheral fibroblast growth factor-2 levels in patients with major depressive disorder

BACKGROUND In vivo and in vitro studies demonstrate the important roles of fibroblast growth factor (FGF) and FGF receptors (FGFRs) in neural survival, neurogenesis, oxidative stress, and emotional behavior. However, evidence on the role of FGF and FGFR in the pathophysiology of major depressive disorder (MDD) remains limited and inconclusive. OBJECTIVES This preliminary meta-analysis aimed to examine changes in peripheral or central FGF and FGFR levels in patients with MDD. DATA SOURCES Electronic research through platform of PubMed and ClinicalTrials.gov. STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS We used the inclusion criteria: articles discussing the comparisons of FGF levels, either in peripheral or central environment, in patients with MDD and in healthy controls (HC); articles on clinical trials in humans; and case-control trials. Case reports or series and nonclinical trials were excluded. STUDY APPRAISAL AND SYNTHESIS METHODS Using a thorough literature search, the FGF/FGFR levels in patients with MDD and HC were compared. Four studies on peripheral FGF-2 and 3 on central FGF-2 and FGFR1 levels were included. RESULTS The findings reveal significantly higher peripheral FGF-2 protein and central FGFR1 RNA levels in patients with MDD than in HC (P = 0.005 and 0.006, separately), but no significant association with clinical variables. There was also no significant difference in the central FGF-2 levels in patients with MDD and in HC (P = 0.180). LIMITATION The study has limitations of a small number of included studies, lack of meta-analysis of the FGF changes along with treatment, and lack of direct evidence on correlation of peripheral FGF-2 with central FGF-2 levels. CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS This preliminary meta-analysis points out a new direction for future studies investigating the relationship among MDD, oxidative stress, and the FGF family.