[Gut microbiota and depression : Pathophysiology of depression: hypothalamic-pituitary-adrenal axis and microbiota-gut-brain axis].
Lima-Ojeda J M,Rupprecht R,Baghai T C
Depression is a chronic disease with a complex multifactorial and still not fully clarified etiology. Due to new insights after recent investigations of the microbiota-gut-brain (MGB) axis, a relationship between a disrupted gut microbiota composition and the probability to develop a depression can be assumed. This hypothesis is supported by evidence that there is a strong communication between gut microbiota and the central nervous system (CNS) and that this communication is mediated through the MGB axis. Apparently, this bidirectional axis can be modulated by environmental factors, such as stress, pharmaceuticals (in particular antibiotics) and dietary habits. Moreover, modulation of this axis can also result in mood alterations. As the hypothalamic-pituitary-adrenal (HPA) axis is a key element regulating the MGB axis and is also related to the pathophysiology of depression, it is important to understand the relationship between both biological systems. An English language literature search was conducted using the biomedical database PubMed. We used combined terms, such as "gut microbiota", "depression", "hypothalamic-pituitary-adrenal axis" or "microbiota-gut-brain axis". The current literature supports the idea that the MGB axis has an impact on the risk to develop depression and that stress modulation through the HPA axis plays a key role in this context.
Depression: Biological markers and treatment.
Nedic Erjavec Gordana,Sagud Marina,Nikolac Perkovic Matea,Svob Strac Dubravka,Konjevod Marcela,Tudor Lucija,Uzun Sandra,Pivac Nela
Progress in neuro-psychopharmacology & biological psychiatry
Nowadays depression is considered as a systemic illness with different biological mechanisms involved in its etiology, including inflammatory response, hypothalamic-pituitary-adrenal (HPA) axis dysregulation and neurotransmitter and neurotrophic systems imbalance. Novel "omics" approaches, such as metabolomics and glycomics provide information about altered metabolic pathways and metabolites, as well as disturbances in glycosylation processes affected by or causing the development of depression. The clinical diagnosis of depression continues to be established based on the presence of the specific symptoms, but due to its heterogeneous underlying biological background, that differs according to the disease stage, there is an unmet need for treatment response biomarkers which would facilitate the process of appropriate treatment selection. This paper provides an overview of the role of major stress response system, the HPA axis, and its dysregulation in depression, possible involvement of neurotrophins, especially brain-derived neurotrophic factor, glial cell line-derived neurotrophic factor and insulin-like growth factor-1, in the development of depression. Article discusses how activated inflammation processes and increased cytokine levels, as well as disturbed neurotransmitter systems can contribute to different stages of depression and could specific metabolomic and glycomic species be considered as potential biomarkers of depression. The second part of the paper includes the most recent findings about available medical treatment of depression. The described biological factors impose an optimistic conclusion that they could represent easy obtainable biomarkers potentially predicting more personalized treatment and diagnostic options.