Why do we not reverse the path? Stress can cause depression, reduction of brain-derived neurotrophic factor and increased inflammation

Itaconate: A promising precursor for treatment of neuroinflammation associated depression

Neuroinflammation triggers the production of inflammatory factors, influences neuron generation and synaptic plasticity, thus playing an important role in the pathogenesis of depression and becoming an important direction of depression prevention and treatment. Itaconate is a metabolite secreted by macrophages in immunomodulatory responses, that has potent immunomodulatory effects and has been proven to exert anti-inflammatory effects in a variety of diseases. Microglia are mononuclear macrophages that reside in the central nervous system (CNS), and may be the source of endogenous itaconate in the brain. Itaconate can directly inhibit succinate dehydrogenase (SDH), reduce the production of NOD-like receptor thermal protein domain associated protein 3 (NLRP3), activate nuclear factor erythroid-2 related factor 2 (Nrf2), and block glycolysis, and thereby improving the depressive symptoms associated with the above mechanisms. Notably, itaconate also indirectly ameliorates the depressive symptoms associated with some inflammatory diseases. With the optimization of the structure and the development of new delivery systems, the application value and therapeutic potential of itaconate have been significantly improved. Dimethyl itaconate (DI) and 4-octyl itaconate (4-OI), cell-permeable derivatives of itaconate, are more suitable for crossing the blood-brain barrier (BBB), exhibiting therapeutic effects in the research of multiple diseases. This article provides an overview of the immunomodulatory effects of itaconate and its potential therapeutic efficacy in inflammatory depression, focusing on the promising application of itaconate as a precursor of antidepressants.

Plasma Concentrations of Neurofilament Light Chain Protein and Brain-Derived Neurotrophic Factor as Consistent Biomarkers of Cognitive Impairment in Alcohol Use Disorder

For a long time, Substance Use Disorders (SUDs) were not considered a component in the etiology of dementia. The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders introduced substance-induced neurocognitive disorders, incorporating this notion to clinical practice. However, detection and monitoring of neurodegenerative processes in SUD patients remain a major clinical challenge, especially when early diagnosis is required. In the present study, we aimed to investigate new potential biomarkers of neurodegeneration that could predict cognitive impairment in SUD patients: the circulating concentrations of Neurofilament Light chain protein (NfL) and Brain-Derived Neurotrophic Factor (BDNF). Sixty SUD patients were compared with twenty-seven dementia patients and forty healthy controls. SUD patients were recruited and assessed using the Psychiatric Research Interview for Substance and Mental (PRISM) and a battery of neuropsychological tests, including the Montreal Cognitive Assessment test for evaluation of cognitive impairment. When compared to healthy control subjects, SUD patients showed increases in plasma NfL concentrations and NfL/BDNF ratio, as well as reduced plasma BDNF levels. These changes were remarkable in SUD patients with moderate-severe cognitive impairment, being comparable to those observed in dementia patients. NfL concentrations correlated with executive function and memory cognition in SUD patients. The parameters "age", "NfL/BDNF ratio", "first time alcohol use", "age of onset of alcohol use disorder", and "length of alcohol use disorder diagnosis" were able to stratify our SUD sample into patients with cognitive impairment from those without cognitive dysfunction with great specificity and sensibility. In conclusion, we propose the combined use of NfL and BDNF (NfL/BDNF ratio) to monitor substance-induced neurocognitive disorder.

BDNF and proBDNF Serum Protein Levels in Obstructive Sleep Apnea Patients and Their Involvement in Insomnia and Depression Symptoms

Introduction: Obstructive sleep apnea (OSA) is a disorder that, apart from somatic sequelae, increases the risk of developing psychiatric conditions. Brain-derived neurotrophic factor (BDNF) signaling pathway is involved in the pathophysiology of depression and insomnia. Therefore, the study aimed to investigate differences in concentrations of BDNF and proBDNF in patients with OSA and healthy individuals, to evaluate diurnal changes of these proteins, and to assess the correlations with psychiatric symptoms. Methods: Sixty individuals following polysomnography (PSG) were divided into two groups based on the apnea-hypopnea index (AHI): OSA patients (AHI ≥ 30; n = 30) and control group (AHI < 5; n = 30). Participants filled out questionnaires: Beck Depression Inventory (BDI), Athens Insomnia Scale (AIS), and Pittsburgh Sleep Quality Index (PSQI). Peripheral blood was collected before and after PSG. Protein concentrations were measured using ELISA. OSA group was divided into subgroups: AIS (−)/AIS (+) (AIS > 5), PSQI (−)/PSQI (+) (PSQI > 5), and BDI (−)/BDI (+) (BDI > 19). Results: No differences in BDNF and proBDNF protein levels were observed between OSA and the control groups. However, BDNF and proBDNF evening protein concentrations were higher in the AIS (+) and PSQI (+) groups (p < 0.001 for all). The BDI (+) group was characterized by lower morning levels of both proteins (p = 0.047 and p = 0.003, respectively). Conclusions: BDNF signaling pathway might be involved in the pathophysiology of depression and insomnia in patients with OSA. BDNF and proBDNF protein levels might be useful in defining OSA phenotypes.