Impact of mast cells in depression disorder: inhibitory effect of IL-37 (new frontiers).

The purpose of this article is to study the involvement of inflammatory mast cells (MCs) in depression which may be inhibited by IL-37. We evaluate mast cells in depression on the basis of our previous experimental data, and using the most relevant studies reported in the literature. Dysfunction of mood, feelings, and thoughts is a major risk factor for several metabolic diseases and may influence the physiology of the body leading to depression. Depression, present in mastocytosis, is an important endogenous process that promotes the activation of meningeal cell receptors through a low-grade neurogenic chronic inflammation, and MCs. Mast cells are localized along meningeal blood vessels and connective tissues, as well as between the ganglion cells and nerve fibers. They are present in the hypothalamus of mammalian brains capable of communication with nerves. MCs are classically activated by binding to IgE cross-link FcεRI high-affinity receptor leading to release a plethora of mediators responsible for the generation of inflammatory cytokines. Corticotropin-releasing hormone (CRH), produced by MCs, has been found in microglial cells where it regulates immune cells and contributes to the pathogenesis of neurodegenerative diseases including depression. Inflammatory cytokines released by MCs aggravate depression and could be partially inhibited by IL-37. A detailed understanding of the interaction between the immune system, including MCs and depression, is necessary in order to address an effective therapy which could include IL-37. As a consequence, the concepts reviewed here have treatment implications.

Quality of life, depression, and cytokine patterns in patients with chronic hepatitis C treated with antiviral therapy.

PURPOSE: To evaluate the effect of chronic hepatitis C and antiviral therapy on health-related quality of life (HRQoL), depression symptoms and cytokine patterns. METHODS: Twenty HCV+ patients treated with peginterferon plus ribavirin were enrolled in this cohort study and invited to complete SF-12 and BDI questionnaires prior to (T0) and at the end of the treatment (T1). HCV-RNA, serum levels of ALT, AST, haemoglobin, ferritin and IFN-gamma, TNF-alpha, IL-2, IL-4, IL-6 and IL-10 were evaluated at T0 and T1. The questionnaire results were correlated to biochemical and cytokine parameters. RESULTS: Two patients (1%) dropped out and 18 HCV patients composed the final sample (11 males (61.1%); mean age 42.5+/-11.9 yr; mean disease duration 9.7+/-6.9 yr). Between T0 and T1 ALT (p=0.02), AST (p=0.052) HCV-RNA (P=0.0002) and haemoglobin levels decreased (p=0.0003), whereas ferritin level increased (P=0.003). Also, at T1 all cytokine levels were augmented. Regarding depression status, at T0 10 patients (55.5%) scored above to the BDI questionnaire (suggesting clinically significant depression), whereas at T1 14 patients scored 10 or above (77.7%). At T1 the mean BDI score increased, but this difference was not significant. Regarding HRQoL, the majority of patients had T0 summary scores < or = 50. At T1 HRQoL changed and scores decreased in 66.7% of the patients. A correlation was observed between the T0 level of ferritin and the amount of change in BDI and SF-12 mental score between T0 and T1 (Spearman rho = -0.56 and +0.61, respectively) and IL-4 level at T0 and the change in BDI and SF-12 mental scores (Spearman rho = -0.49 and +0.45, respectively). CONCLUSION: BDI, SF-12, IL-4 and ferritin are good tools to predict the appearance of depressive symptoms and worsening of the quality of life in the HCV+ population.

Expression and secretion of CXCL8 (IL-8), release of tryptase and transcription of histidine decarboxylase mRNA by anti-IgE-activated human umbilical cord blood-derived cultured mast cells.

Activation of cytokine receptors and alterations in cytokines are thought to play important roles in neuronal dysfunction and in the pathogenesis of the nervous system diseases. CXCL8 (IL-8) is a CXC chemokine with chemotactic and inflammatory properties. Chemokines control mast cell infiltration in several inflammatory diseases, including stress and neurological dysfunctions. Using isolated human umbilical cord blood-derived cultured mast cells (HUCMC) from hematopoietic stem cells CD34+, mast cells were immunologically activated with anti-IgE at concentrations of 1, 5, 10 and 20 microg/ml leading to the dose-dependent production of IL-8 (p < 0.05). The increase in IL-8 mRNA expression was also noted when the cells were treated with anti-IgE at 10 microg/ml for 6 h. Immunologically activated HUCMC provoked the generation of tryptase in a dose- and time-dependent manner. We also found increased histidine decarboxylase (HDC) expression in activated HUCMC after 6 h of incubation, a rate-limiting enzyme responsible for the generation of histamine from histidine. Taken together, these results confirm that anti-IgE-activated mast cells release inflammatory mediators including CXCL8, a CXC chemokine which regulates several biological effects of mast cells, e.g. chemoattraction, and possibly causes cell arrest.