A randomised placebo controlled trial of delipidated, deglycolipidated Mycobacterium vaccae as immunotherapy for psoriatic arthritis

Chronic Mycobacterium avium infection differentially affects the cytokine expression profile of three mouse strains, but has no effect on behavior

One of the most remarkable findings in the immunology and neuroscience fields was the discovery of the bidirectional interaction between the immune and the central nervous systems. This interplay is tightly regulated to maintain homeostasis in physiological conditions. Disruption in this interplay has been suggested to be associated with several neuropsychiatric disorders. Most studies addressing the impact of an immune system disruption on behavioral alterations focus on acute pro-inflammatory responses. However, chronic infections are highly prevalent and associated with an altered cytokine milieu that persists over time. Studies addressing the potential effect of mycobacterial infections on mood behavior originated discordant results and this relationship needs to be further addressed. To increase our understanding on the effect of chronic infections on the central nervous system, we evaluated the role of Mycobacterium avium infection. A model of peripheral chronic infection with M. avium in female from three mouse strains (Balb/c, C57BL/6, and CD-1) was used. The effect of the infection was evaluated in the cytokine expression profile (spleen and hippocampus), hippocampal cell proliferation, neuronal plasticity, serum corticosterone production and mood behavior. The results show that M. avium peripheral chronic infection induces alterations not just in the peripheral immune system but also in the central nervous system, namely in the hippocampus. Interestingly, the cytokine expression profile alterations vary between mouse strains, and are not accompanied by hippocampal cell proliferation or neuronal plasticity changes. Accordingly, no differences were observed in locomotor, anxious and depressive-like behaviors, in any of the mouse strains used. We conclude that the M. avium 2447 infection-induced alterations in the cytokine expression profile, both in the periphery and the hippocampus, are insufficient to alter hippocampal plasticity and behavior.

A Review of the Benefits of Nature Experiences: More Than Meets the Eye

Evidence that experiences of nature can benefit people has accumulated rapidly. Yet perhaps because of the domination of the visual sense in humans, most research has focused on the visual aspects of nature experiences. However, humans are multisensory, and it seems likely that many benefits are delivered through the non-visual senses and these are potentially avenues through which a physiological mechanism could occur. Here we review the evidence around these lesser studied sensory pathways—through sound, smell, taste, touch, and three non-sensory pathways. Natural sounds and smells underpin experiences of nature for many people, and this may well be rooted in evolutionary psychology. Tactile experiences of nature, particularly beyond animal petting, are understudied yet potentially fundamentally important. Tastes of nature, through growing and consuming natural foods, have been linked with a range of health and well-being benefits. Beyond the five senses, evidence is emerging for other non-visual pathways for nature experiences to be effective. These include ingestion or inhalation of phytoncides, negative air ions and microbes. We conclude that (i) these non-visual avenues are potentially important for delivering benefits from nature experiences; (ii) the evidence base is relatively weak and often based on correlational studies; and (iii) deeper exploration of these sensory and non-sensory avenues is needed.

Current and potential immune therapies and vaccines in the management of psoriasis

Psoriasis is a chronic, immune skin disease associated with significant morbidity. Development of psoriasis is influenced by numerous genes, one allele is HLA-CW*0602. Other genes and single nucleotide polymorphisms affect immunologic pathways and antimicrobial peptide synthesis. Dendritic cells initiate psoriasis by activating T-cells toward a Th1 and Th17 response, with increased cytokines including TNF-α, IL-6, -12, -17, -22, and -23. IL-22 appears to promote keratinocyte dedifferentiation and increased antimicrobial peptide synthesis while TNF-α and IL-17 induce leukocyte localization within the psoriatic plaque. These recent insights identifying key cytokine pathways have led to the development of inhibitors with significant efficacy in the treatment of psoriasis. While a strategy for vaccine modulation of the immune response in psoriasis is in progress, with new technology they may provide a cost-effective long-term treatment that may induce tolerance or targeted self-inhibition for patients with autoimmune disorders, such as psoriasis.

Taking the Perspective that a Depressive State Reflects Inflammation: Implications for the Use of Antidepressants

This paper reviews both the evidence that supports the characterization of depression as an inflammatory disorder and the different biochemical mechanisms that have been postulated for the connection between inflammation and depression. This association offers credible explanation for the short term efficacy of antidepressants, which have short term anti-inflammatory effects. Evidence for those anti-inflammatory effects is discussed. Evidence of the contrary long-term effects of antidepressants, which increase rather than decrease inflammation, is also reviewed. It is argued that this increase in inflammation would predict an increase in chronicity among depressed patients that have been treated with antidepressants drugs, which has been noted in the literature. A brief discussion of alternatives for decreasing inflammation, some of which have demonstrated efficacy in ameliorating depression, is presented.

Can we vaccinate against depression?

Major depression is common in the context of autoimmune and inflammatory diseases and is frequently associated with persistently raised levels of proinflammatory cytokines and other markers of inflammation, even in the absence of another diagnosable immune pathology to account for these findings. Therefore immunoregulation-inducing vaccines or manipulations of the gut microbiota might prevent or treat depression. These strategies are already undergoing clinical trials for chronic inflammatory disorders, such as allergies, autoimmunity and inflammatory bowel disease. In this article, we summarize data suggesting that this approach might be effective in depression and encourage the initiation of clinical vaccination trials in this disorder.

A randomized placebo-controlled trial of methotrexate in psoriatic arthritis

Objective. MTX is widely used to treat synovitis in PsA without supporting trial evidence. The aim of our study was to test the value of MTX in the first large randomized placebo-controlled trial (RCT) in PsA.

Methods. A 6-month double-blind RCT compared MTX (15 mg/week) with placebo in active PsA. The primary outcome was PsA response criteria (PsARC). Other outcomes included ACR20, DAS-28 and their individual components. Missing data were imputed using multiple imputation methods. Treatments were compared using logistic regression analysis (adjusted for age, sex, disease duration and, where appropriate, individual baseline scores).

Results. Four hundred and sixty-two patients were screened and 221 recruited. One hundred and nine patients received MTX and 112 received placebo. Forty-four patients were lost to follow-up (21 MTX, 23 placebo). Twenty-six patients discontinued treatment (14 MTX, 12 placebo). Comparing MTX with placebo in all randomized patients at 6 months showed no significant effect on PsARC [odds ratio (OR) 1.77, 95% CI 0.97, 3.23], ACR20 (OR 2.00, 95% CI 0.65, 6.22) or DAS-28 (OR 1.70, 95% CI 0.90, 3.17). There were also no significant treatment effects on tender and swollen joint counts, ESR, CRP, HAQ and pain. The only benefits of MTX were reductions in patient and assessor global scores and skin scores at 6 months (P = 0.03, P < 0.001 and P = 0.02, respectively). There were no unexpected adverse events.

Conclusions. This trial of active PsA found no evidence for MTX improving synovitis and consequently raises questions about its classification as a disease-modifying drug in PsA.

Trial registration. Current Controlled Trials, www.controlled-trials.com, ISRCTN:54376151.

Psoriatic Arthritis: A Review

Psoriatic arthritis (PsA) is a seronegative inflammatory spondyloarthropathy occurring in individuals with psoriasis. Psoriasis precedes joint disease in approximately 80% of PsA cases. The clinical course of PsA varies from mild arthritis to a severe, debilitating erosive arthropathy that affects functional capacity and quality of life of patients. The incidence of PsA is gender neutral, but a significant genetic component exists. Hallmark clinical features include dystrophic nail changes in the fingers or toes, dactylitis, and enthesitis. Many drugs indicated for use in rheumatoid arthritis have been found useful in the treatment of PsA, suggesting a similar immune-mediated etiology. Nonsteroidal anti-inflammatory drugs and intraarticular corticosteroids are often sufficient to manage mild PsA. Moderate to severe forms of the disease require the initiation of disease modifying anti-rheumatic drugs. Failure of two disease modifying antirheumatic drugs justifies the initiation of biologic therapy with tumor necrosis factor-α inhibitors.

The hygiene hypothesis and psychiatric disorders

The hygiene hypothesis proposes that several chronic inflammatory disorders (allergies, autoimmunity, inflammatory bowel disease) are increasing in prevalence in developed countries because a changing microbial environment has perturbed immunoregulatory circuits which normally terminate inflammatory responses. Some stress-related psychiatric disorders, particularly depression and anxiety, are associated with markers of ongoing inflammation, even without any accompanying inflammatory disorder. Moreover, pro-inflammatory cytokines can induce depression, which is commonly seen in patients treated with interleukin-2 or interferon-alpha. Therefore, some psychiatric disorders in developed countries might be attributable to failure of immunoregulatory circuits to terminate ongoing inflammatory responses. This is discussed in relation to the effects of the immune system on a specific group of brain serotonergic neurons involved in the pathophysiology of mood disorders.

Identification of an immune-responsive mesolimbocortical serotonergic system: potential role in regulation of emotional behavior

Peripheral immune activation can have profound physiological and behavioral effects including induction of fever and sickness behavior. One mechanism through which immune activation or immunomodulation may affect physiology and behavior is via actions on brainstem neuromodulatory systems, such as serotonergic systems. We have found that peripheral immune activation with antigens derived from the nonpathogenic, saprophytic bacterium, Mycobacterium vaccae, activated a specific subset of serotonergic neurons in the interfascicular part of the dorsal raphe nucleus (DRI) of mice, as measured by quantification of c-Fos expression following intratracheal (12 h) or s.c. (6 h) administration of heat-killed, ultrasonically disrupted M. vaccae, or heat-killed, intact M. vaccae, respectively. These effects were apparent after immune activation by M. vaccae or its components but not by ovalbumin, which induces a qualitatively different immune response. The effects of immune activation were associated with increases in serotonin metabolism within the ventromedial prefrontal cortex, consistent with an effect of immune activation on mesolimbocortical serotonergic systems. The effects of M. vaccae administration on serotonergic systems were temporally associated with reductions in immobility in the forced swim test, consistent with the hypothesis that the stimulation of mesolimbocortical serotonergic systems by peripheral immune activation alters stress-related emotional behavior. These findings suggest that the immune-responsive subpopulation of serotonergic neurons in the DRI is likely to play an important role in the neural mechanisms underlying regulation of the physiological and pathophysiological responses to both acute and chronic immune activation, including regulation of mood during health and disease states. Together with previous studies, these findings also raise the possibility that immune stimulation activates a functionally and anatomically distinct subset of serotonergic neurons, different from the subset of serotonergic neurons activated by anxiogenic stimuli or uncontrollable stressors. Consequently, selective activation of specific subsets of serotonergic neurons may have distinct behavioral outcomes.

Prospects for vaccines for allergic and other immunologic skin disorders

The human skin hosts a variety of immune response-associated components that together form the skin immune system. Any abnormality in the functioning of the skin immune system leads to a variety of dermatologic complications, including dermatitis, psoriasis, and eczema. Exposure to antigens/allergens can lead to allergic skin disorders such as atopic dermatitis, urticaria, and allergic contact dermatitis. Recent investigations have provided new insights into the immunologic processes leading to the development of skin diseases. T cells play a central role in the activation and regulation of immune responses by recognizing antigen and inducing cytokine production. Despite advances in the understanding of the immunologic events leading to the development of skin diseases, no effective prevention measure exists. Current therapeutic treatments are based on either alleviating the symptoms or suppressing the immune system with immunosuppressive drugs. Allergen-specific immunotherapy is expected to induce specific T cells that abolish allergen-induced proliferation of T helper cells, as well as their cytokine production. Recent approaches using recombinant protein, polycytosine guanine oligonucleotides, and plasmid DNA for vaccination suggest the possibility of protection against these skin disorders. The involvement of T cells in psoriasis indicates that the development of a T-cell receptor peptide vaccine may be beneficial. Dendritic cell-based vaccines using tolerogenic dendritic cells that can induce T-cell tolerance have been shown to be useful in dealing with autoimmune disorders and allergic conditions. In the light of these developments, this article presents the current status and prospects of developing vaccines for allergic and other immunologic skin disorders.

Phase II randomized, placebo-controlled trial of M. vaccae-derived protein (PVAC) for the treatment of psoriasis

The treatment effect against psoriasis of an antigen (delipidated, deglycolipidated form of M. vaccae-PVAC) was investigated. One hundred and sixty-five patients were enrolled in three arms (50 or 15 microg or placebo), each receiving a total of two intradermal injections (days 0 and 21). At week 12, a 75% decrease in psoriasis area and severity index was similar among the studied groups (13, 9 and 18%, p=0.429). The overall incidence of adverse events was significantly higher in the PVAC treated groups when compared to placebo (98.2, 87.3 and 70.9%; p<0.001) largely due to local reactions that were limited for the most part to grades 1 and 2 in severity and were self-limiting. Despite its overall safety, PVAC was not clearly indicated to be superior to placebo in the treatment of psoriasis in this study.

Treatment update on spondyloarthropathy

PURPOSE OF REVIEW

The unexpected success of the tumor necrosis factor antagonists in ankylosing spondylitis and psoriatic arthritis has generated considerable enthusiasm regarding the therapeutic potential of these drugs. By contrast, concerns regarding the high cost and long-term safety of the tumor necrosis factor blocking agents have prompted investigators to take a closer look at more traditional anti-inflammatory agents and to explore novel therapeutic targets. The purpose of this review is to summarize treatment advances in spondylarthropathy over the past year and to discuss potential future therapies.

RECENT FINDINGS

Recent studies indicate that the morbidity of ankylosing spondylitis and PsA are considerably higher than previously reported. Etanercept, infliximab and adalimumab safely and effectively relieved the signs and symptoms of psoriatic arthritis patients in phase III trials. Etanercept and infliximab were also effective in phase III trials in ankylosing spondylitis. Etanercept slowed radiographic progression in psoriatic arthritis trials, but it is not known whether tumor necrosis factor antagonists can prevent structural damage in ankylosing spondylitis. One trial showed that methotrexate may be effective for relieving the pain of axial disease in ankylosing spondylitis but these findings contradict two previous studies. For reactive arthritis and undifferentiated spondylarthropathy, a combination of antibiotics may be more effective than a single antibiotic for the relief of musculoskeletal symptoms. Last, potential therapeutic targets include interleukin-1, interleukin-12, B lymphocytes, accessory molecules on T lymphocytes, and angiogenic factors.

SUMMARY

Phase III trials have confirmed that tumor necrosis factor antagonists are effective and safe for the treatment of ankylosing spondylitis and psoriatic arthritis. For patients who do not respond to tumor necrosis factor blockade, several treatment options are under study. Information from these trials will more clearly define the role of disease-modifying antirheumatic drugs, novel therapeutic agents, and antibiotics in the treatment of spondylarthropathy.

Treatment advances in psoriatic arthritis

Treatment of psoriatic arthritis, like the treatment of rheumatoid arthritis, now commonly includes the use of inhibitors of tumor necrosis factor in addition to traditional synthetic disease-modifying antirheumatic drugs. This paper examines the most recent data from therapeutic trials in psoriatic arthritis, with particular emphasis on the effectiveness of the tumor necrosis factor inhibitors. Recent data on potential future therapies is discussed as well, along with data on the mechanisms of current therapies that may have relevance for future treatment approaches.