Intranasal Versus Intravenous Dexamethasone to Treat Hospitalized COVID-19 Patients: A Randomized Multicenter Clinical Trial.

BACKGROUND: SARS-CoV2 induces flu-like symptoms that can rapidly progress to severe acute lung injury and even death. The virus also invades the central nervous system (CNS), causing neuroinflammation and death from central failure. Intravenous (IV) or oral dexamethasone (DXM) reduced 28 d mortality in patients who required supplemental oxygen compared to those who received conventional care alone. Through these routes, DMX fails to reach therapeutic levels in the CNS. In contrast, the intranasal (IN) route produces therapeutic levels of DXM in the CNS, even at low doses, with similar systemic bioavailability. AIMS: To compare IN vs. IV DXM treatment in hospitalized patients with COVID-19. METHODS: A controlled, multicenter, open-label trial. Patients with COVID-19 (69) were randomly assigned to receive IN-DXM (0.12 mg/kg for three days, followed by 0.6 mg/kg for up to seven days) or IV-DXM (6 mg/d for 10 d). The primary outcome was clinical improvement, as defined by the National Early Warning Score (NEWS) ordinal scale. The secondary outcome was death at 28 d between IV and IN patients. Effects of both treatments on biochemical and immunoinflammatory profiles were also recorded. RESULTS: Initially, no significant differences in clinical severity, biometrics, and immunoinflammatory parameters were found between both groups. The NEWS-2 score was reduced, in 23 IN-DXM treated patients, with no significant variations in the 46 IV-DXM treated ones. Ten IV-DXM-treated patients and only one IN-DXM patient died. CONCLUSIONS: IN-DMX reduced NEWS-2 and mortality more efficiently than IV-DXM, suggesting that IN is a more efficient route of DXM administration.

Sympathetic-Immune Interactions during Different Types of Immune Challenge.

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.

To protect or to kill: A persisting Darwinian immune dilemma.

The immune system, which evolved as a protective system, can paradoxically mediate lethal effects when it is over-activated. These effects can be traced back to infected insects and are mainly mediated by phylogenetically old cytokines that have been found already in starfishes and sponges. We hypothesize that these anti-homeostatic effects are important for restricting the cumulative risk of transmission of highly mutating environmental pathogens that may endanger species, particularly when they start to originate and expand. Considering the Darwinian view that evolution is a permanent process, this anti-homeostatic program is preserved and expressed even when there is no risk for the species. Here, we review these aspects and discuss how evolutionary-imposed anti-homeostatic immune programs are expressed during acute and chronic human diseases, which can be further aggravated in the absence of medical interventions. The relevance of early identification of ancestral biomarkers that predict a shift from protective to deleterious immune outcomes is emphasized.

Intranasal dexamethasone: a new clinical trial for the control of inflammation and neuroinflammation in COVID-19 patients.

BACKGROUND: By end December of 2021, COVID-19 has infected around 276 million individuals and caused over 5 million deaths worldwide. Infection results in dysregulated systemic inflammation, multi-organ dysfunction, and critical illness. Cells of the central nervous system are also affected, triggering an uncontrolled neuroinflammatory response. Low doses of glucocorticoids, administered orally or intravenously, reduce mortality among moderate and severe COVID-19 patients. However, low doses administered by these routes do not reach therapeutic levels in the CNS. In contrast, intranasally administered dexamethasone can result in therapeutic doses in the CNS even at low doses. METHODS: This is an approved open-label, multicenter, randomized controlled trial to compare the effectiveness of intranasal versus intravenous dexamethasone administered in low doses to moderate and severe COVID-19 adult patients. The protocol is conducted in five health institutions in Mexico City. A total of 120 patients will be randomized into two groups (intravenous vs. intranasal) at a 1:1 ratio. Both groups will be treated with the corresponding dexamethasone scheme for 10 days. The primary outcome of the study will be clinical improvement, defined as a statistically significant reduction in the NEWS-2 score of patients with intranasal versus intravenous dexamethasone administration. The secondary outcome will be the reduction in mortality during hospitalization. CONCLUSIONS: This protocol is currently in progress to improve the efficacy of the standard therapeutic dexamethasone regimen for moderate and severe COVID-19 patients. TRIAL REGISTRATION: ClinicalTrials.gov NCT04513184 . Registered November 12, 2020. Approved by La Comisión Federal para la Protección contra Riesgos Sanitarios (COFEPRIS) with identification number DI/20/407/04/36. People are currently being recruited.

Nose-to-Brain Delivery of Dexamethasone: Biodistribution Studies in Mice.

Neuroinflammation (NI) is an important physiologic process which promotes the tissue repair and homeostatic maintenance in the central nervous system after different types of insults. However, when it is exacerbated and sustained in time, NI plays a critical role in the pathogenesis of different neurologic diseases. The high systemic doses required for brain-specific targeting lead to severe undesirable effects. The intranasal (IN) route has been proposed as an alternative drug administration route for a better NI control. Herein, the brain biodistribution of intranasally administered dexamethasone versus intravenously administered one is reported. A higher amount of dexamethasone was found in every analyzed region of those brains of intranasally administered mice. HPLC analysis also revealed that IN administration allows Dex to arrive faster and in a greater concentration to the brain in comparison with intravenous administration, data confirmed by immunofluorescence and HPLC analysis. These data support the proposal of the IN administration of Dex as an alternative for a more efficient control of NI. SIGNIFICANCE STATEMENT: This work highlights the biodistribution of dexamethasone after its intranasal administration. Intranasal administration allows for a faster arrival, better distribution, and a higher concentration of the drug within the brain compared to its intravenous administration. These results explain some of the evidence shown in a previous work in which dexamethasone controls neuroinflammation in a murine stroke model and can be used to propose alternative treatments for neuroinflammatory diseases.

Intranasal Dexamethasone Reduces Mortality and Brain Damage in a Mouse Experimental Ischemic Stroke Model.

Neuroinflammation triggered by the expression of damaged-associated molecular patterns released from dying cells plays a critical role in the pathogenesis of ischemic stroke. However, the benefits from the control of neuroinflammation in the clinical outcome have not been established. In this study, the effectiveness of intranasal, a highly efficient route to reach the central nervous system, and intraperitoneal dexamethasone administration in the treatment of neuroinflammation was evaluated in a 60-min middle cerebral artery occlusion (MCAO) model in C57BL/6 male mice. We performed a side-by-side comparison using intranasal versus intraperitoneal dexamethasone, a timecourse including immediate (0 h) or 4 or 12 h poststroke intranasal administration, as well as 4 intranasal doses of dexamethasone beginning 12 h after the MCAO versus a single dose at 12 h to identify the most effective conditions to treat neuroinflammation in MCAO mice. The best results were obtained 12 h after MCAO and when mice received a single dose of dexamethasone (0.25 mg/kg) intranasally. This treatment significantly reduced mortality, neurological deficits, infarct volume size, blood-brain barrier permeability in the somatosensory cortex, inflammatory cell infiltration, and glial activation. Our results demonstrate that a single low dose of intranasal dexamethasone has neuroprotective therapeutic effects in the MCAO model, showing a better clinical outcome than the intraperitoneal administration. Based on these results, we propose a new therapeutic approach for the treatment of the damage process that accompanies ischemic stroke.

Intranasal Methylprednisolone Effectively Reduces Neuroinflammation in Mice With Experimental Autoimmune Encephalitis.

Relapsing-remitting multiple sclerosis, the most common form, is characterized by acute neuroinflammatory episodes. In addition to continuous disease-modifying therapy, these relapses require treatment to prevent lesion accumulation and progression of disability. Intravenous methylprednisolone (1-2 g for 3-5 days) is the standard treatment for relapses. However, this treatment is invasive, requires hospitalization, leads to substantial systemic exposure of glucocorticoids, and can only reach modest concentrations in the central nervous system (CNS). Intranasal delivery may represent an alternative to deliver relapse treatment directly to the CNS with higher concentrations and reducing side effects. Histopathological analysis revealed that intranasal administration of methylprednisolone to mice with experimental autoimmune encephalomyelitis (EAE) suppressed the neuroinflammatory peak, and reduced immune cell infiltration and demyelination in the CNS similarly to intravenous administration. Treatment also downregulated Iba1 and GFAP expression. A similar significant reduction of IL-1ß, IL-6, IL-17, IFN-γ, and TNF-α levels in the spinal cord was attained in both intranasal and intravenously treated mice. No damage in the nasal cavity was found after intranasal administration. This study demonstrates that intranasal delivery of methylprednisolone is as efficient as the intravenous route to treat neuroinflammation in EAE.

The immune system as a sensorial system that can modulate brain functions and reset homeostasis.

Evidence indicates that activated immune cells release products, typically cytokines, that can convey information to the brain about the type of ongoing peripheral immune responses. This evidence led colleagues and me to categorize the immune system as another sensorial system that, upon receiving this information, can emit neuroendocrine signals with immunoregulatory functions that can also reset homeostatic mechanisms. Here, I discuss evidence and clues indicating (1) possible mechanisms by which cytokines, such as those of the interleukin 1 (IL-1) family, can reset energy homeostasis to balance the high fuel requirement of the immune system and the brain; and (2) the possibility that the tripartite synapse, which includes astrocytes as a third component, processes and integrates immune signals at brain levels with other sensorial signals that the central nervous system permanently receives.

Glucocorticoids and sympathetic neurotransmitters modulate the acute immune response to Trypanosoma cruzi.

Evidence suggests that natural and adaptive immune responses can trigger neuroendocrine responses. Here, we discuss changes in the activity of the hypothalamus-pituitary-adrenal axis and in autonomic nerves, predominantly of the sympathetic nervous system, in a mouse model of acute infection with Trypanosoma cruzi. The endocrine response includes a marked increased release of glucocorticoid and a decrease of immune-stimulatory hormones, such as dehydroepiandrosterone sulfate, prolactin, and growth hormone during infection. These endocrine changes result in reduced proinflammatory cytokine production, increased regulatory/effector T cell ratio, and thymus atrophy. The sympathetic activity in the spleen of infected mice is also markedly reduced. However, the residual sympathetic activity can modulate the immune response to the parasite, as shown by increased mortality and production of proinflammatory cytokines in sympathetically denervated, infected mice. The outcome of the neuroendocrine response is the moderation of the intensity of the immune response to the parasite, an effect that results in delayed mortality in susceptible mice, and favors the course toward chronicity in more resistant animals.

Sepsis: developing new alternatives to reduce neuroinflammation and attenuate brain injury.

Sepsis occurs when a systemic infection induces an uncontrolled inflammatory response that results in generalized organ dysfunction. The exacerbated peripheral inflammation can induce, in turn, neuroinflammation which may result in severe impairment of the central nervous system (CNS). Indeed, the ensuing blood-brain barrier disruption associated with sepsis promotes glial activation and starts a storm of proinflammatory cytokines in the CNS that leads to brain dysfunction in sepsis survivors. Endotoxic shock induced in mice by peripheral injection of lipopolysaccharides closely resembles the peripheral and central inflammation observed in sepsis. In this review, we provide an overview of the neuroinflammatory features in sepsis and of recent progress toward the development of new anti-neuroinflammatory therapies seeking to reduce mortality and morbidity in sepsis survivors.

Treatment-Resistant Human Extraparenchymal Neurocysticercosis: An Immune-Inflammatory Approach to Cysticidal Treatment Outcome.

OBJECTIVE: The aim of this study is to analyze the immune-endocrine profile in neurocysticercosis (NC) patients resistant to cysticidal treatment. METHODS: The inflammatory and regulatory responses of 8 resistant NC patients with extraparenchymal parasites and 5 healthy controls were evaluated through flow cytometry. Serum interleukin levels were measured by ELISA and catecholamines levels by high performance liquid chromatography. RESULTS: Higher percentages of Tr1, CD4+CD25+FOXP3+CD127- and CD4+CD45RO+FOXP3HI were found in NC patients compared with healthy controls, but no difference was found in catecholamine levels. Antigen-specific proliferative immune response was observed in NC patients. Neither anti-inflammatory nor pro-inflammatory cytokines showed differences between patients and controls, but IL-6 levels were lower in treatment-resistant NC patients. In addition, TGFß showed a significant negative correlation with dopamine. CONCLUSIONS: Altogether, these results may point to a modulation of the neuroinflammation in these patients that could indirectly favor cysticercal survival in CNS microenvironment.

The clinical recovery of tuberculosis patients undergoing specific treatment is associated with changes in the immune and neuroendocrine responses.

Tuberculosis (TB) caused by Mycobacterium tuberculosis is a health problem worldwide. Patients with pulmonary TB show a neuro-immune-endocrine imbalance characterized by an impaired cellular immunity together with increased plasma levels of cortisol, pro- and anti-inflammatory cytokines and markedly decreased dehydroepiandrosterone (DHEA) levels. Extending these findings, we now investigated the immune-endocrine profile of TB patients undergoing specific treatment. Patients (n = 24) were bled at diagnosis (T0), 2, 4, 6 months after treatment initiation and 3 months following its completion. At T0, TB patients showed increased plasma levels of interleukin-6 (IL-6), C reactive protein, interferon-gamma (IFN-γ) and transforming growth factor beta (TGF-ß). These mediators decreased during treatment, reaching levels similar to those from healthy controls (n = 26). Specific treatment led to an increased lymphoproliferative response along with clinical improvement. Newly diagnosed patients had low levels of DHEA, with increased cortisol amounts and cortisol/DHEA ratio, which normalized upon specific treatment. As regards glucocorticoid receptors (GR), TB patients at diagnosis presented a reduced mRNA GRα/GRß ratio in their peripheral blood mononuclear cells. Furthermore, multivariate analysis showed that cortisol/DHEA ratio was positively associated with inflammatory mediators for which this ratio may constitute a disease biomarker. Anti-mycobacterial treatment results in a better immune-endocrine scenario for the control of physiopathological processes accompanying disease development and hence implied in clinical recovery.

Immune-Neuro-Endocrine Reflexes, Circuits, and Networks: Physiologic and Evolutionary Implications.

The existence of a network of interactions between the immune and nervous systems that influences host defenses and brain functions is now well-established. Here we discuss how immune and classical neuro/sensorial signals are processed in the brain and how neuro-endocrine immunoregulatory and behavioral responses are integrated. Considering the ability of brain cells to produce cytokines, originally described as immune cell products, we propose that the tripartite synapse plays a central role in the integration of neuro-endocrine-immune interactions. We also propose that the immune-neuro-endocrine responses that influence the course of transmissible and other diseases predisposing to infections can be relevant for evolution, either by restoring health or by mediating an active process of negative selection.

The sympathetic nervous system affects the susceptibility and course of Trypanosoma cruzi infection.

Trypanosoma cruzi (T. cruzi) is an intracellular parasite that causes Chagas' disease, a major health problem in Latin America. Using a murine model of infection with this parasite, we have previously shown that corticosterone blood levels are markedly elevated during the course of the disease in C57Bl/6 male mice and that this increase is protective for the host by restricting the production of pro-inflammatory cytokines. Since the hypothalamus-pituitary-adrenal (HPA) axis usually operates in a concerted way with the sympathetic nervous system (SNS), we have now studied whether noradrenergic nerves can affect the course of T. cruzi infection and the sexual dimorphism observed in the disease. We found a decreased splenic noradrenaline concentration and content, paralleled by a reduction in noradrenergic nerve fibers in the spleen of infected mice, and increased HPA axis activity. These alterations were more marked in males than in females. When the spontaneous loss of noradrenergic nerve fibers was advanced by chemical sympathectomy prior to infection, males died earlier and mortality significantly increased in females. Chemical denervation did not significantly affect the concentration of specific IgM and IgG2a antibodies to T. cruzi, and did not worsen myocarditis, but resulted in increased parasitemia and IL-6 and IFN-γ blood levels. The results obtained in this model of parasitic disease provide further indications of the relevance of interactions between the immune system and the SNS for host defense.

Mimicking disruption of brain-immune system-joint communication results in collagen type II-induced arthritis in non-susceptible PVG rats.

The brain-immune system-joint communication is disrupted during collagen type II (CII) arthritis in DA rats. Since PVG rats are not susceptible to arthritis induction, comparison of hypothalamic and peripheral neuro-endocrine and immune responses between immunized DA and PVG rats might help to explain their different susceptibility to develop the disease. PVG and DA rats were immunized with CII. Corticosterone, neurotransmitters, anti-CII antibodies, and cytokine concentrations in plasma, and hypothalamic neurotransmitters and cytokines were determined by ELISA, Luminex, HPLC and RT-qPCR. Adrenalectomy or sham-operation was performed in PVG and DA rats 14 days before immunization. Basal plasma corticosterone and adrenaline concentrations were significantly higher, and plasma cytokines and hypothalamic noradrenaline were lower in PVG rats than in DA rats. While DA rats developed severe arthritis upon immunization (maximum score 16), only 12 out of 28 PVG rats showed minimal symptoms (score 1-2). The density of sympathetic nerve fibers in arthritic joints of DA rats markedly decreased, but it remained stable in immunized PVG rats. The ratio corticosterone to IL-1ß levels in plasma was markedly higher in immunized PVG rats than in arthritic DA rats. Adrenalectomy resulted in severe arthritis in PVG rats upon immunization with CII. While DA rats show an altered immune-brain communication that favors the development of arthritis, PVG rats express a protective neuro-endocrine milieu, particularly linked to the basal tone of the HPA axis. Mimicking disruption of this axis elicits arthritis in non-susceptible PVG rats.

Gender-associated differential expression of cytokines in specific areas of the brain during helminth infection.

Intraperitoneal infection with Taenia crassiceps cysticerci in mice alters several behaviors, including sexual, aggressive, and cognitive function. Cytokines and their receptors are produced in the central nervous system (CNS) by specific neural cell lineages under physiological and pathological conditions, regulating such processes as neurotransmission. This study is aimed to determine the expression patterns of cytokines in various areas of the brain in normal and T. crassiceps-infected mice in both genders and correlate them with the pathology of the CNS and parasite counts. IL-4, IFN-γ, and TNF-α levels in the hippocampus and olfactory bulb increased significantly in infected male mice, but IL-6 was downregulated in these regions in female mice. IL-1ß expression in the hippocampus was unaffected by infection in either gender. Our novel findings demonstrate a clear gender-associated pattern of cytokine expression in specific areas of the brain in mammals that parasitic infection can alter. Thus, we hypothesize that intraperitoneal infection is sensed by the CNS of the host, wherein cytokines are important messengers in the host-parasite neuroimmunoendocrine network.

Physiologic versus diabetogenic effects of interleukin-1: a question of weight.

Pleiotropic effects, great potency, and the capacity to induce its own production are distinguishing characteristics of IL-1. Among the multiple physiological effects of this cytokine, we emphasize here its role in supporting immune processes by stimulating most immune cells, and in re-setting glucose homeostasis. These aspects are complementary because stimulatory actions of IL-1 may be due to its capacity to increase glucose uptake by immune cells in the periphery and to affect the control of glucose homeostasis at brain levels, so as to deviate this main fuel to immune cells during inflammatory and infectious diseases. Thus, IL-1 can contribute to maintain a lean phenotype, inhibit food intake, and exert hypoglycemic effects. However, these effects of IL-1 can be overridden particularly when it is overproduced ectopically in other tissues, as it occurs during the autoimmune process that destroys the pancreas and causes type 1 diabetes, or when obesity triggers its production in adipose tissue and influences the development of type 2 diabetes. During obesity, products of enlarged adipocytes, e.g. fatty acids, are sensed as danger signals by infiltrating immune cells and, together with hypoxia, results in an ectopic overproduction of IL-1 that is largely mediated by activation of the NLRP3-caspase-1 inflammasome. Insulin and leptin resistance develops by mutual IL-1ß-TNFα induction, and hyperglycemia causes ectopic production of IL-1 in the pancreas, which deregulates insulin production and favors the development of type 2 diabetes. In conclusion, whether IL-1 exerts physiologic or pathologic effects depends on its amount and on the spatial and temporal pattern of its production.

Helminth infection alters mood and short-term memory as well as levels of neurotransmitters and cytokines in the mouse hippocampus.

UNLABELLED: Helminthic infections are important causes of morbidity and mortality in many developing countries, where children bear the greatest health burden. The ability of parasites to cause behavioral changes in the host has been observed in a variety of host-parasite systems, including the Taenia crassiceps-mouse model. In murine cysticercosis, mice exhibit a disruption in the sexual, aggressive and avoidance predator behaviors. OBJECTIVE: The present study was conducted to characterize short-term memory and depression-like behavior, as well as levels of neurotransmitters and cytokines in the hippocampus of cysticercotic male and female mice. METHODS: Cytokines were detected by RT-PCR and neurotransmitters were quantified by HPLC. RESULTS: Chronic cysticercosis infection induced a decrease in short-term memory in both male and female mice, having a more pronounced effect in females. Infected females showed a significant increase in forced swimming tests with a decrease in immobility. In contrast, male mice showed an increment in total activity and ambulation tests. Serotonin levels decreased by 30% in the hippocampus of infected females whereas noradrenaline levels significantly increased in infected males. The hippocampal expression of IL-4 increased in infected female mice, but decreased in infected male mice. CONCLUSION: Our study suggests that intraperitoneal chronic infection with cysticerci in mice leads to persistent deficits in tasks dependent on the animal's hippocampal function. Our findings are a first approach to elucidating the role of the neuroimmune network in controlling short-term memory and mood in T. crassiceps-infected mice.

A cytokine network involving brain-borne IL-1ß, IL-1ra, IL-18, IL-6, and TNFα operates during long-term potentiation and learning.

We have previously shown that long-term potentiation (LTP) induces hippocampal IL-1ß and IL-6 over-expression, and interfering their signalling either inhibits or supports, respectively, LTP maintenance. Consistently, blockade of endogenous IL-1 or IL-6 restricts or favours hippocampal-dependent memory, effects that were confirmed in genetically manipulated mice. Since cytokines are known for their high degree of mutual crosstalk, here we studied whether a network of cytokines with known neuromodulatory actions is activated during LTP and learning. We found that, besides IL-1ß and IL-6, also IL-1 receptor antagonist (IL-1ra) and IL-18, but not TNFα are over-expressed during LTP maintenance in freely moving rats. The increased expression of these cytokines is causally related to an increase in synaptic strength since it was abrogated when LTP was interfered by blockade of NMDA-glutamate receptors. Likewise, IL-1 and IL-6 were found to be over-expressed in defined regions of the hippocampus during learning a hippocampus-dependent task. However, during learning, changes in IL-18 were restricted to the dorsal hippocampus, and no differences in TNFα and IL1-ra expression were noticed in the hippocampus. Noticeably, IL-1ra transcripts were significantly reduced in the prefrontal cortex. The relation between cytokine expression and learning was causal because such changes were not observed in animals from a pseudo-trained group that was subject to the same manipulation but could not learn the task. Taken together with previous studies, we conclude that activation of a cytokine network in the brain is a physiologic relevant phenomenon not only for LTP maintenance but also for certain types of learning.