Serum brain-derived neurotrophic factor and stability of depressive symptoms in coronary heart disease patients: A prospective study

Kuhlmann SL, Tschorn M, Arolt V, Beer K, Brandt J, Grosse L, Haverkamp W, Muller-Nordhorn J, Rieckmann N, Waltenberger J, Warnke K, Hellweg R, Strohle A

Abstract

OBJECTIVE: Brain-derived neurotrophic factor (BDNF) supports neurogenesis, angiogenesis, and promotes the survival of various cell types in the brain and the coronary system. Moreover, BDNF is associated with both coronary heart disease (CHD) and depression. The current study aims to investigate whether serum BDNF levels are associated with the course of depressive symptoms in CHD patients. METHODS: At baseline, N=225 CHD patients were enrolled while hospitalized. Of these, N=190 (84{\%}) could be followed up 6 months later. Depressive symptoms were assessed both at baseline and at the 6-months follow-up using the Patient Health Questionnaire (PHQ-9). Serum BDNF concentrations were measured using fluorometric Enzyme-linked immunosorbent assays (ELISA). RESULTS: Logistic regression models showed that lower BDNF levels were associated with persistent depressive symptoms, even after adjustment for age, sex, smoking and potential medical confounders. The incidence of depressive symptoms was not related to lower BDNF levels. However, somatic comorbidity (as measured by the Charlson Comorbidity Index) was significantly associated with the incidence of depressive symptoms. CONCLUSIONS: Our findings suggest a role of BDNF in the link between CHD and depressive symptoms. Particularly, low serum BDNF levels could be considered as a valuable biomarker for the persistence of depressive symptoms among depressed CHD patients.