Neuroimmunomodulation最新文献

Background: More than a century ago, experimental work and clinical observations revealed the functional communication between the brain and the peripheral immune system. This is documented on the one hand by studies first demonstrating the effects of catecholamines on the circulation of leukocytes in experimental animals and humans, and on the other hand via the work of Russian physiologist Ivan Petrovic Pavlov and his coworkers, reporting observations that associative learning can modify peripheral immune functions. This work later fell into oblivion since little was known about the endocrine and immune system's function and even less about the underlying mechanisms of how learning, a central nervous system activity, could affect peripheral immune responses.

Summary: In this article, we embark on a fascinating exploration of the historical trajectory of behaviorally conditioned immune responses.

Key message: We will pay homage to the visionary scientists who laid the groundwork for this field of research, tracing its evolution from early theories of how associative learning can affect immunity to the modern-day insights that behavioral conditioning of pharmacological responses can be exploited to improve the efficacy of medical interventions for patients.

Background: The neuro-endocrine regulation of immune functions is based on a complex network of interactions. As part of this series of articles, we refer here to immune-sympathetic interactions that are triggered by different types of immune challenge.

Summary: We mention the initial hypothesis that led to the proposal that the sympathetic nervous system (SNS) is involved in immunoregulation. We next refer mainly to our initial work performed at a time when most immunologists were concentrated in clarifying aspects of the immune system that are essential for its regulation from within. The first approach was to explore whether immune responses to innocuous antigens and superantigens can elicit changes in the activity of the SNS, and their potential relevance for the regulation of the activity of the immune system. The following step was to explore whether comparable immune-SNS interactions are detected in different models of diseases with immune components, such as parasitic and viral infections and autoimmune pathologies.

Key messages: We pose some general considerations that may at least partially explain seemly discrepant findings, and remark the importance of interpreting immunoregulatory effects of the SNS together with other neuro-endocrine inputs that simultaneously occur when the activity of the immune system changes. Finally, we provide some arguments to re-consider the use of the expression "reflex" in immunology.

Background: The brain and the immune systems represent the two primary adaptive systems within the body. Both are involved in a dynamic process of communication, vital for the preservation of mammalian homeostasis. This interplay involves two major pathways: the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system.

Summary: The establishment of infection can affect immunoneuroendocrine interactions, with functional consequences for immune organs, particularly the thymus. Interestingly, the physiology of this primary organ is not only under the control of the central nervous system (CNS) but also exhibits autocrine/paracrine regulatory circuitries mediated by hormones and neuropeptides that can be altered in situations of infectious stress or chronic inflammation. In particular, Chagas disease, caused by the protozoan parasite Trypanosoma cruzi (T. cruzi), impacts upon immunoneuroendocrine circuits disrupting thymus physiology. Here, we discuss the most relevant findings reported in relation to brain-thymic connections during T. cruzi infection, as well as their possible implications for the immunopathology of human Chagas disease.

Key messages: During T. cruzi infection, the CNS influences thymus physiology through an intricate network involving hormones, neuropeptides, and pro-inflammatory cytokines. Despite some uncertainties in the mechanisms and the fact that the link between these abnormalities and chronic Chagasic cardiomyopathy is still unknown, it is evident that the precise control exerted by the brain over the thymus is markedly disrupted throughout the course of T. cruzi infection.

Introduction: Dimethyl fumarate (DMF) has shown potential for protection in various animal models of neurological diseases. However, the impact of DMF on changes in peripheral immune organs and the central nervous system (CNS) immune cell composition after ischemic stroke remains unclear.

Methods: Eight-week-old C57BL/6J mice with photothrombosis ischemia and patients with acute ischemic stroke (AIS) were treated with DMF. TTC staining, flow cytometry, and immunofluorescence staining were used to evaluate the infarct volume and changes in immune cells in the periphery and the CNS.

Results: DMF reduced the infarct volume on day 1 after PT. DMF reduced the percentages of peripheral immune cells, such as neutrophils, dendritic cells, macrophages, and monocytes, on day 1, followed by NK cells on day 3 and B cells on day 7 after PT. In the CNS, DMF significantly reduced the percentage of monocytes in the brain on day 3 after PT. In addition, DMF increased the number of microglia in the peri-infarct area and reduced the number of neurons in the peri-infarct area in the acute and subacute phases after PT. In AIS patients, B cells decreased in patients receiving alteplase in combination with DMF.

Conclusion: DMF can change the immune environment of the periphery and the CNS, reduce infarct volume in the acute phase, promote the recruitment of microglia and preserve neurons in the peri-infarct area after ischemic stroke.

Background: That neuroimmune interaction occurs in chronic pain conditions has been established for over a century, since the discovery of neurogenic inflammation in the periphery. However, the central aspects of neuroimmune interactions have not been fully appreciated until the late 1900s, when a growing interest in how cytokines in the cerebrospinal fluid (CSF) might be relevant in chronic pain conditions emerged. Since then, the field has evolved, and nowadays neuroinflammation is considered to be involved in the pathophysiology of chronic pain. Whether or not pain conditions can be called "neuroinflammatory" is a matter of debate. This review summarizes the results from studies investigating cytokines in the CSF in various pain conditions, and critically discusses neuroimmune aspects of pain conditions using previously proposed hallmarks of neuroinflammation as a framework.

Summary: Fifty-two papers were summarized and their results evaluated according to (a) the level of the measured cytokines in patients compared to controls, and (b) the correlation between cytokine level and pain intensity. A subdivision based on pain type was also conducted for each of the 52 studies. A total of 49 proteins have been studied in at least 5 studies, 21 of which were upregulated in a majority of studies. IL-8 was specifically upregulated in a majority of studies of nociceptive pain conditions. Regarding correlation to pain intensity, there is a scarcity of data but 31 proteins were upregulated and correlated with pain in at least one study. Of these, 24 proteins were negatively correlated with pain, and 7 were positively correlated. None of the most studied cytokines, such as TNF, IL-1b, IL-6, IL-8, CCL2/MCP1, BDNF, or bNGF, were consistently correlated to pain.

Key messages: There is sufficient evidence to say that chronic pain conditions come with an upregulation of several cytokines. However, the majority of correlations to symptomatology seem to be negative, indicating that the cytokines might play a protective role that has not been broadly considered. Calling chronic pain conditions neuroinflammatory seems wrong; instead, a more suitable term for depicting the findings would, perhaps, be to talk about neuroimmune activation.