Relationship of cognitive functioning with progenitor cells of the olfactory epithelium in patients with depression after eight weeks of fluoxetine treatment

Abstract

Depression is related to cognitive dysfunction, which could be mediated by alterations in neurogenesis. Research suggests that pharmacological treatment induces cognitive changes by generating neurogenesis-promoting factors at least in animal models of depression. Interestingly, several studies suggest that olfactory alterations occurred in depression. Those alterations may be linked to the neurogenic process occurring in the olfactory epithelium. Thus, the objective of this study was to evaluate the relationship between progenitor cells of the olfactory epithelium (OPC) and cognitive functioning in patients with depression before and after eight weeks of fluoxetine treatment. The initial and final measurements revealed a significant relationship of OPC with the Rey–Osterrieth Complex Figure Test, but a significant relationship was only observed between brain-derived neurotrophic factor (BDNF) quantified in the conditioned medium of OPC and the Digit Ordering Test in the final measurements. We propose a relationship between the OPC and visuospatial capacity, working memory and information organization. However, changes in the expression of neurogenesis marker proteins in the OPC as a biological reading of the benefits of antidepressant treatment and its relationship with cognitive functions deserve to be studied in the future.

Keywords

• Depressive disorder
• Adult neurogenesis
• BDNF
• Memory
• Olfactory epithelium
• Memory and learning tests