Clomipramine and imipramine suppress clinical signs and T and B cell response to myelin proteins in experimental autoimmune neuritis in Lewis rats

Pharmacological insights into autophagy modulation in autoimmune diseases

As a cellular bulk degradation and survival mechanism, autophagy is implicated in diverse biological processes. Genome-wide association studies have revealed the link between autophagy gene polymorphisms and susceptibility of autoimmune diseases including systemic lupus erythematosus (SLE) and inflammatory bowel disease (IBD), indicating that autophagy dysregulation may be involved in the development of autoimmune diseases. A series of autophagy modulators have displayed protective effects on autoimmune disease models, highlighting the emerging role of autophagy modulators in treating autoimmune diseases. This review explores the roles of autophagy in the autoimmune diseases, with emphasis on four major autoimmune diseases [SLE, rheumatoid arthritis (RA), IBD, and experimental autoimmune encephalomyelitis (EAE)]. More importantly, the therapeutic potentials of small molecular autophagy modulators (including autophagy inducers and inhibitors) on autoimmune diseases are comprehensively analyzed.

The Anti-inflammatory Effect of the Tricyclic Antidepressant Clomipramine and Its High Penetration in the Brain Might Be Useful to Prevent the Psychiatric Consequences of SARS-CoV-2 Infection

At the time of writing (December 2020), coronavirus disease 2019 (COVID-19) has already caused more than one million deaths worldwide, and therefore, it is imperative to find effective treatments. The “cytokine storm” induced by Severe Acute Respiratory Syndrome-Coronavirus type 2 (SARS-CoV-2) is a good target to prevent disease worsening, as indicated by the results obtained with tocilizumab and dexamethasone. SARS-CoV-2 can also invade the brain and cause neuro-inflammation with dramatic neurological manifestations, such as viral encephalitis. This could lead to potentially incapacitating long-term consequences, such as the development of psychiatric disorders, as previously observed with SARS-CoV. Several pathways/mechanisms could explain the link between viral infection and development of psychiatric diseases, especially neuro-inflammation induced by SARS-CoV-2. Therefore, it is important to find molecules with anti-inflammatory properties that penetrate easily into the brain. For instance, some antidepressants have anti-inflammatory action and pass easily through the blood brain barrier. Among them, clomipramine has shown very strong anti-inflammatory properties in vitro, in vivo (animal models) and human studies, especially in the brain. The aim of this review is to discuss the potential application of clomipramine to prevent post-infectious mental complications. Repositioning and testing antidepressants for COVID-19 management could help to reduce peripheral and especially central inflammation and to prevent the acute and particularly the long-term consequences of SARS-CoV-2 infection.

Selegiline and clomipramine effects on lymphocyte subsets, regulatory T cells and sheep red blood cell (SRBC)-induced humoral immune response after in vivo administration in mice

We aimed at investigating the influence of clomipramine and selegiline administered in vivo in mice on lymphocyte subsets in lymphoid organs and SRBC-induced humoral immune response. Balb/c mice were given 7 or 14 oral doses (1 mg/kg) of selegiline or clomipramine. Lymphocyte B and T subsets and splenic regulatory T cell (Treg) subset were determined in non-immunized mice 24 and 72 h after the last dose of the drugs. Some mice treated with 7 doses were immunized with sheep red blood cells (SRBC) 2 h after the last dose, and their number of antibody forming cells, haemagglutinin titers and splenocyte subsets were determined. An increase in T lymphocytes and a decrease in B cells were visible in peripheral lymphoid organs, especially after 14 doses of selegiline or clomipramine in non-immunized mice, as well as in spleens of SRBC-immunized mice. The most pronounced change was a decrease in CD4⁺/CD8⁺ ratio resulting mainly from an increase in CD8⁺ subset after seven doses of the drugs in the non-immunized mice. However, it was of a transient nature, as it disappeared after 14 doses of the drugs. The tested drugs only slightly affected thymocyte maturation and did not alter Treg subset. Selegiline and clomipramine transiently stimulated IgG production in SRBC-immunized mice. Both selegiline and clomipramine administered in vivo modulated lymphocyte subsets. This immunomodulatory effect depended on the drug as well as duration of administration.

Systematic screening of generic drugs for progressive multiple sclerosis identifies clomipramine as a promising therapeutic

The treatment of progressive multiple sclerosis (MS) is unsatisfactory. One reason is that the drivers of disease, which include iron-mediated neurotoxicity, lymphocyte activity, and oxidative stress, are not simultaneously targeted. Here we present a systematic screen to identify generic, orally available medications that target features of progressive MS. Of 249 medications that cross the blood–brain barrier, 35 prevent iron-mediated neurotoxicity in culture. Of these, several antipsychotics and antidepressants strongly reduce T-cell proliferation and oxidative stress. We focus on the antidepressant clomipramine and found that it additionally inhibits B-lymphocyte activity. In mice with experimental autoimmune encephalomyelitis, a model of MS, clomipramine ameliorates clinical signs of acute and chronic phases. Histologically, clomipramine reduces inflammation and microglial activation, and preserves axonal integrity. In summary, we present a systematic approach to identify generic medications for progressive multiple sclerosis with the potential to advance rapidly into clinical trials, and we highlight clomipramine for further development.

Progressive multiple sclerosis is an inflammatory and degenerative disease of the central nervous system, for which effective treatment is lacking. The authors carry out a screen to identify orally available generic medications, and show that the antidepressant clomipramine reduces pathology in mouse models.

Somatic drugs for psychiatric diseases: aspirin or simvastatin for depression?

The evolution in the understanding of the neurobiology of most prevalent mental disorders such as major depressive disorder (MDD), bipolar disorder or schizophrenia has not gone hand in hand with the synthesis and clinical use of new drugs that would represent a therapeutic revolution such as that brought about by selective serotonin reuptake inhibitors (SSRIs) or atypical antipsychotics. Although scientists are still a long way from understanding its true aetiology, the neurobiological concept of depression has evolved from receptor regulation disorder, to a neurodegenerative disorder with a hippocampal volume decrease with the controversial reduction in neurotrophins such as BDNF, to current hypotheses that consider depression to be an inflammatory and neuroprogressive process. As regards antidepressants, although researchers are still far from knowing their true mechanism of action, they have gone from monoaminergic hypotheses, in which serotonin was the main protagonist, to emphasising the anti-inflammatory action of some of these drugs, or the participation of p11 protein in their mechanism of action.In the same way, according to the inflammatory hypothesis of depression, it has been proposed that some NSAIDS such as aspirin or drugs like simvastatin that have an anti-inflammatory action could be useful in some depressive patients. Despite the fact that there may be some data to support their clinical use, common sense and the evidence advise us to use already tested protocols and wait for the future to undertake new therapeutic strategies.

Mechanistic explanations how cell-mediated immune activation, inflammation and oxidative and nitrosative stress pathways and their sequels and concomitants play a role in the pathophysiology of unipolar depression

This paper reviews that cell-mediated-immune (CMI) activation and inflammation contribute to depressive symptoms, including anhedonia; anxiety-like behaviors; fatigue and somatic symptoms, e.g. illness behavior or malaise; and mild cognitive impairment (MCI). These effects are in part mediated by increased levels of pro-inflammatory cytokines (PICs), e.g. interleukin-1 (IL-1), IL-6 and tumor necrosis factor (TNF)α, and Th-1-derived cytokines, such as IL-2 and interferon (IFN)γ. Moreover, new pathways, i.e. concomitants and sequels of CMI activation and inflammation, were detected in depression: (1) Induction of indoleamine 2,3-dioxygenase (IDO) by IFNγ and some PICs is associated with depleted plasma tryptophan, which may interfere with brain 5-HT synthesis, and increased production of anxiogenic and depressogenic tryptophan catabolites. (2) Increased bacterial translocation may cause depression-like behaviors by activating the cytokine network, oxidative and nitrosative stress (O&NS) pathways and IDO. (3) Induction of O&NS causes damage to membrane ω3 PUFAs, functional proteins, DNA and mitochondria, and autoimmune responses directed against intracellular molecules that may cause dysfunctions in intracellular signaling. (4) Decreased levels of ω3 PUFAs and antioxidants, such as coenzyme Q10, glutathione peroxidase or zinc, are associated with an increased inflammatory potential; more oxidative damage; the onset of specific symptoms; and changes in the expression or functions of brain 5-HT and N-methyl-d-aspartate receptors. (5) All abovementioned factors cause neuroprogression, that is a combination of neurodegeneration, neuronal apoptosis, and lowered neurogenesis and neuroplasticity. It is concluded that depression may be the consequence of a complex interplay between CMI activation and inflammation and their sequels/concomitants which all together cause neuroprogression that further shapes the depression phenotype. Future research should employ high throughput technologies to collect genetic and gene expression and protein data from patients with depression and analyze these data by means of systems biology methods to define the dynamic interactions between the different cell signaling networks and O&NS pathways that cause depression.

Inflammation in depression: is adiposity a cause?

Mounting evidence indicates that inflammation may play a significant role in the development of depression. Patients with depression exhibit increased inflammatory markers, and administration of cytokines and other inflammatory stimuli can induce depressive symptoms. Mechanisms by which cytokines access the brain and influence neurotransmitter systems relevant to depression have also been described, as have preliminary findings indicating that antagonizing inflammatory pathways may improve depressive symptoms. One primary source of inflammation in depression appears to be adiposity. Adipose tissue is a rich source of inflammatory factors including adipokines, chemokines, and cytokines, and a bidirectional relationship between adiposity and depression has been revealed. Adiposity is associated with the development of depression, and depression is associated with adiposity, reflecting a potentional vicious cycle between these two conditions which appears to center around inflammation. Treatments targeting this vicious cycle may be especially relevant for the treatment and prevention of depression as well as its multiple comorbid disorders such as cardiovascular disease, diabetes, and cancer, all of which have also been associated with both depression and inflammation.

Depression is an inflammatory disease, but cell-mediated immune activation is the key component of depression

The first findings that depression is characterized by cell-mediated immune activation and inflammation were published between 1990-1993 (Maes et al.). Recently, it was reported that--based on meta-analysis results--depression is an inflammatory disorder because the plasma levels of two cytokines are increased, i.e. interleukin-(IL)-6 and tumor necrosis factor-α (TNFα). The same meta-analysis found that plasma IL-2 and interferon-(IFN)γ levels are not altered in depression, suggesting that there is no T cell activation in that illness. The present paper reviews the body of evidence that depression is accompanied by cell-mediated immune activation. The findings include: increased serum levels of the soluble IL-2 receptor (sIL-2R) and the sCD8 molecule; increased numbers and percentages of T cells bearing T cell activation markers, such as CD2+CD25+, CD3+CD25+, and HLA-DR+; increased stimulated production of IFNγ; higher neopterin and sTNFR-1 or sTNFR-2 levels; induction of indoleamine 2,3-dioxygenase (IDO) with lowered levels of plasma tryptophan and increased levels of tryptophan catabolites along the IDO pathway (TRYCATs); and glucocorticoid resistance in immune cells. Interferon-α (IFNα)-based immunotherapy shows that baseline and IFNα-induced activation of T cells, IDO activity and TRYCAT formation are related to the development of IFNα-induced depressive symptoms. Animal models of depression show that a cell-mediated immune response is related to the development of depression-like behavior. Antidepressants and mood stabilizers suppress different aspects of cell-mediated immunity and rather specifically target IFNγ production. This review shows that inflammation and cell-mediated immune activation are key factors in depression.

Sertoli cell therapy: a novel possible treatment strategy for treatment-resistant major depressive disorder

By the year 2020, depression will be the 2nd most common health problem in the world. Current medications to treat depression are effective in less than 50% of patients. There is the need for novel treatments for depression to address the high rates of resistance to current treatment and the chronic residual symptoms in many patients treated for depression. The heterogeneity of major depressive disorder suggests that multiple neurocircuits and neurochemicals are involved in its pathogenesis thus, finding an alternative to neurotransmitter agonist- or antagonist-based treatments offers an important new approach. Cellular therapy is an emerging treatment strategy for multiple diseases, including depression. Based upon their in vivo function as "nurse cells" within the testis and the documented viability, efficacy, and safety of Sertoli cells transplanted into multiple tissues, including brain, the potential for these cells to provide a neuroprotective, anti-inflammatory, and trophic environment for neurons should be considered. It is proposed that the combination of self-protective, immunoregulatory and trophic properties of Sertoli cells may confer a unique potential for depression treatment and avoid many of the risks and challenges associated with stem cell therapies. At the very least, studies of the effects of Sertoli cell transplantation will add substantially to our understanding of the cellular and molecular processes that underlie depression.

Eating ourselves to death (and despair): the contribution of adiposity and inflammation to depression

Obesity and related metabolic conditions are of epidemic proportions in most of the world, affecting both adults and children. The accumulation of lipids in the body in the form of white adipose tissue in the abdomen is now known to activate innate immune mechanisms. Lipid accumulation causes adipocytes to directly secrete the cytokines interleukin (IL) 6 and tumor necrosis factor alpha (TNFalpha), but also monocyte chemoattractant protein 1 (MCP-1), which results in the accumulation of leukocytes in fat tissue. This sets up a chronic inflammatory state which is known to mediate the association between obesity and conditions such as cardiovascular disease, type 2 diabetes, and cancer. There is also a substantial literature linking inflammation with risk for depression. This includes the observations that: (1) people with inflammatory diseases such as multiple sclerosis, cardiovascular disease, and psoriasis have elevated rates of depression; (2) many people administered inflammatory cytokines such as interferon alpha develop depression that is indistinguishable from depression in non-medically ill populations; (3) a significant proportion of depressed persons show upregulation of inflammatory factors such as IL-6, C-reactive protein, and TNFalpha; (4) inflammatory cytokines can interact with virtually every pathophysiologic domain relevant to depression, including neurotransmitter metabolism, neuroendocrine function, and synaptic plasticity. While many factors may contribute to the association between inflammatory mediators and depression, we hypothesize that increased adiposity may be one causal pathway. Mediational analysis suggests a bi-directional association between adiposity and depression, with inflammation possibly playing an intermediary role.

Neuroimmune mechanisms of cytokine-induced depression: current theories and novel treatment strategies

The relationships between immune and neural function are an increasingly important area of study for neuropsychiatric disorders, in particular depression. This is exemplified by the growing number of publications on cytokines and depression during the last 10 years, as compared to earlier decades. This review summarizes the current theories and novel treatment strategies for depression, with a focus on cytokine-induced depression. Neuroimmune mechanisms are now viewed as central to the development of depressive symptoms and emerging evidence is beginning to identify the neural circuits involved in cytokine-induced depression. The current diagnostic categories for depression, as defined by the Diagnostic and Statistical Manual of Mental Disorders, however, are not etiologically or biologically derived, and it has been proposed that "depression", likely reflects multiple pathogeneses leading to varying symptom constellations. As we move toward a better biological understanding of depression-related symptom constellations or syndromes, the term "depression" may prove inadequately broad, and an integration of interdisciplinary literatures will increase in importance. Future research should aim to characterize these depression-related symptom constellations or syndromes better with the goal of optimizing treatment strategies.

Novel therapeutic approaches to Guillain-Barré syndrome

Guillain-Barré syndrome is an autoimmune disease which occurs throughout the world. Whilst the majority of patients can expect a reasonable recovery, about 10% die and 10% are left disabled with current therapy. The standard treatment is a five day course of iv. immunoglobulin, given at a dose of 0.4 g/kg/day, with plasma exchange as an equally efficacious alternative. Steroids are ineffective in Guillain-Barré syndrome. All new potential therapeutic agents need to be tested in addition to the standard agents available. Future potential therapies are suggested by the study of the animal model experimental autoimmune neuritis in the Lewis rat. Whilst in theory it is possible to target the different stages of the immune response, in practice not all of the steps at which experimental autoimmune neuritis can be prevented will be translatable to human Guillain-Barré syndrome. This is because Guillain-Barré syndrome probably presents after the immune reaction has been ongoing for some time and therefore early aspects of the immune response cannot be prevented. Many of the possible measures would have widespread immunosuppressive effects which would be unacceptable to patients. Interfering with the immune response by attempting to block antigen binding or inducing tolerance may not be practical, owing to the possibility of exacerbating disease. Once we have a more thorough understanding of the pathogenesis of Guillain-Barré syndrome, then immune-specific therapy for Guillain-Barré syndrome may become a possibility, rather than general immunosuppressive measures. Trials of beta-interferon and of a combination of steroid and i.v. immunoglobulin are underway. A trial of a second course of i.v. immunoglobulin is planned.

Treatment of immune-mediated inflammatory neuropathies

Experimental models have suggested potential new treatments for human inflammatory neuropathy, but current practice is largely based on empirical trials. Evidence from randomized trials supports the use of intravenous immunoglobulin in Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal motor neuropathy with conduction block (MMNCB). In Guillain-Barré syndrome and CIDP intravenous immunoglobulin is equivalent to but more convenient than plasma exchange. In MMNCB adequate comparative studies of intravenous immunoglobulin and plasma exchange have not been performed. Corticosteroid treatment is beneficial in CIDP, but not in Guillain-Barré syndrome and may worsen MMNCB. More randomized trials and systematic reviews are needed to improve the evidence base for clinical practice.

Amelioration of experimental allergic neuritis by sodium fusidate (fusidin): suppression of IFN-gamma and TNF-alpha and enhancement of IL-10

The immunomodulating antibiotic drug fusidic acid and its sodium salt sodium fusidate (fusidin) ameliorate several organ-specific immunoinflammatory diseases. Because preliminary observations suggest that fusidin may also exert a beneficial effect in Guillain-Barré syndrome (GBS), here we have studied the effects of fusidin on actively induced experimental autoimmune neuritis (EAN) in rats, a known animal model for GBS. Both prophylactic and therapeutic treatment with fusidin (4 mg/rat day ip) markedly ameliorated the clinical course of the disease compared to vehicle-treated animals. The beneficial effects were associated with profound modifications of the capacity of these rats to produce and release pro- and anti-inflammatory cytokines such as IFN-gamma, TNF-alpha and IL-10, which are important in regulating the development of EAN.