Morphine Induces CD4+ T Cell IL-4 Expression through an Adenylyl Cyclase Mechanism Independent of the Protein Kinase A Pathway

Causal Effects and Immune Cell Mediators of Prescription Analgesic Use and Risk of Liver Cancer and Precancerosis in European Population: A Mendelian Randomization Study

Diverse clinical observations and basic studies have been conducted to explore the implications of analgesic medications in liver diseases. However, the direct causal relationship between prescription analgesic use (PAU) and the risk of liver cancer and precancerosis remains unclear. Thus, we aimed to reveal the conceivable causal effect of PAU on liver cancer and precancerosis, with immune cells as mediating factors. Two-sample Mendelian randomization (MR) analyses were performed to ascertain the causality of PAU on liver cancer and precancerosis. Sensitivity analysis approaches were employed to assess the heterogeneity and pleiotropy of results. Our findings revealed a causal correlation between different PAUs and the risk of liver cancer and alcoholic liver disease (ALD). Specifically, salicylic acid derivatives (SADs) and anilide medications were found to have a protective effect on liver cancer. And non-steroidal anti-inflammatory drugs (NSAIDs) and anilide medications showed a causal impact on ALD. Finally, mediation analyses found that anilide medications influence liver cancer through different immune cell phenotypes. Our research provides new genetic evidence for the causal impact of PAU on liver cancer and precancerosis, with the mediating role of immune cells demonstrated, offering a valuable foundation for researching analgesic medications in liver cancer and precancerosis treatment.

Adenosine induces IL-31 secretion by T-helper 2 cells: Implication for the effect of adenosine on atopic dermatitis and its therapeutic strategy

Interleukin (IL)-31 is a recently-identified cytokine with a well-defined role in the pathogenesis of pruritus. Previously, we reported that adenosine upregulates IL-17A secretion by T-helper (Th)17 cells; however, the effect of adenosine on T cell subsets other than Th17 remains unclear. In this report, we show that adenosine upregulated production of IL-31 by cluster of differentiation (CD)4⁺ T cells. IL-31 was also upregulated by administration of an adenosine A2a receptor (A2aR) agonist (PSB0777), and adenosine-mediated IL-31 production was inhibited by an A2aR antagonist (istradefylline). Production of Th2-related cytokines (IL-4, IL-10, and IL-13) by CD4⁺ T cells showed the same tendency. Immune subset analyses revealed that adenosine upregulated IL-31 secretion by CD4⁺ chemokine receptor 3^high T cells, and that Th2 cells differentiated from naïve CD4⁺ T cells. Administration of istradefylline to mice with atopic dermatitis suppressed the symptoms, suggesting that A2aR antagonists are an effective treatment for inflammatory dermatitis. Taken together, the results indicate that adenosine upregulates secretion of Th2-related cytokines by effector T cells in the skin, thereby triggering atopic dermatitis and associated pruritus.

Morphine in Combination with Ketamine Improves Cervical Cancer Pain and Suppresses Immune Function via the JAK3/STAT5 Pathway

Background

The role of ketamine as an adjuvant for morphine in the treatment of cancer pain and immune functions has been confirmed. This study aimed to explore the role of morphine and ketamine on cancer pain and T cells of patients with cervical cancer (CC).

Methods

T cells were isolated from peripheral blood mononuclear cells (PBMC) of CC patients by positive selection using anti-CD3 beads. The isolated T cells were assigned into three groups: the control group, the morphine group, and the morphine + ketamine (Mor + Ket) group. The percentages of CD4⁺ and CD8⁺ were analyzed by flow cytometry. The levels of interferon (IFN)-γ, interleukin (IL)-2, and IL-17 and the corresponding mRNA expression in vitro were determined using ELISA and qRT-PCR, respectively. Western blotting was used for detection of JAK3/STAT5 pathway-related proteins after naltrexone treatment in vitro. Afterwards, all the patients were further divided into the morphine group and the Mor + Ket group in accordance with the principles of the randomized and double-blind method to assess pain intensity.

Results

Our in vivo results showed that drug combinations relieved cancer pain more effectively than morphine intervention. The in vitro results demonstrated that the combination of morphine and ketamine may decrease CD4⁺ percentage, CD4⁺/CD8⁺ ratio, and the levels of IFN-γ, IL-2, and IL-17 via the JAK3/STAT5 pathway.

Conclusions

Our finding indicated that morphine-ketamine combination could improve cancer pain and repress immune function via the JAK3/STAT5 pathway in the progression of CC.

Opioidergic Signaling-A Neglected, Yet Potentially Important Player in Atopic Dermatitis

Atopic dermatitis (AD) is one of the most common skin diseases, the prevalence of which is especially high among children. Although our understanding about its pathogenesis has substantially grown in recent years, and hence, several novel therapeutic targets have been successfully exploited in the management of the disease, we still lack curative treatments for it. Thus, there is an unmet societal demand to identify further details of its pathogenesis to thereby pave the way for novel therapeutic approaches with favorable side effect profiles. It is commonly accepted that dysfunction of the complex cutaneous barrier plays a central role in the development of AD; therefore, the signaling pathways involved in the regulation of this quite complex process are likely to be involved in the pathogenesis of the disease and can provide novel, promising, yet unexplored therapeutic targets. Thus, in the current review, we aim to summarize the available potentially AD-relevant data regarding one such signaling pathway, namely cutaneous opioidergic signaling.

The A118G single-nucleotide polymorphism in OPRM1 is a risk factor for asthma severity

BACKGROUND

Although population studies have implicated emotional burden in asthma severity, the underlying genetic risk factors are not completely understood. We aimed to evaluate the genetic influence of a functional single-nucleotide polymorphism (SNP) in the stress-related μ-opioid receptor gene (OPRM1; A118G SNP, rs1799971) on asthma severity.

METHODS

We initially assessed disease severity in asthmatic outpatients carrying A118G. Using an ovalbumin-induced experimental asthma rodent model harboring the functionally equivalent SNP, we investigated the mechanism by which this SNP influences the allergic immune response.

RESULTS

Among 292 outpatients, 168 underwent airway hyperresponsiveness (AHR) to methacholine testing. Compared with patients carrying the AA and AG genotypes, those carrying the GG genotype exhibited enhanced AHR. The stress levels were presumed to be moderate among patients and were comparable among genotypes. Compared with Oprm1 AA mice, GG mice demonstrated aggravated asthma-related features and increased pulmonary interleukin-4⁺CD4⁺ effector and effector memory T cells under everyday life stress conditions. Intraperitoneal naloxone methiodide injection reduced effector CD4⁺ T cell elevation associated with increased eosinophil numbers in bronchoalveolar lavage fluid of GG mice to the levels in AA mice, suggesting that elevated Th2 cell generation in the bronchial lymph node (BLN) of GG mice induces enhanced eosinophilic inflammation.

CONCLUSIONS

Without forced stress exposure, patients with asthma carrying the OPRM1 GG genotype exhibit enhanced AHR, attributable to enhanced Th2 cell differentiation in the regional lymph node. Further research is necessary to elucidate the role of the OPRM1 A118G genotype in the Th2 cell differentiation pathway in the BLN.

Diverse innate stimuli activate basophils through pathways involving Syk and IκB kinases

Mature basophils play critical inflammatory roles during helminthic, autoimmune, and allergic diseases through their secretion of histamine and the type 2 cytokines interleukin 4 (IL-4) and IL-13. Basophils are activated typically by allergen-mediated IgE cross-linking but also by endogenous "innate" factors. The aim of this study was to identify the innate stimuli (cytokines, chemokines, growth factors, hormones, neuropeptides, metabolites, and bacterial products) and signaling pathways inducing primary basophil activation. Basophils from naïve mice or helminth-infected mice were cultured with up to 96 distinct stimuli and their influence on basophil survival, activation, degranulation, and IL-4 or IL-13 expression were investigated. Activated basophils show a heterogeneous phenotype and segregate into distinct subsets expressing IL-4, IL-13, activation, or degranulation markers. We find that several innate stimuli including epithelial derived inflammatory cytokines (IL-33, IL-18, TSLP, and GM-CSF), growth factors (IL-3, IL-7, TGFβ, and VEGF), eicosanoids, metabolites, TLR ligands, and type I IFN exert significant direct effects on basophils. Basophil activation mediated by distinct upstream signaling pathways is always sensitive to Syk and IκB kinases-specific inhibitors but not necessarily to NFAT, STAT5, adenylate cyclase, or c-fos/AP-1 inhibitors. Thus, basophils are activated by very diverse mediators, but their activation seem controlled by a core checkpoint involving Syk and IκB kinases.

Peripheral Opioid Receptor Blockade Enhances Epithelial Damage in Piroxicam-Accelerated Colitis in IL-10-Deficient Mice

Mucosal CD4+ T lymphocytes display a potent opioid-mediated analgesic activity in interleukin (IL)-10 knockout mouse model of inflammatory bowel diseases (IBD). Considering that endogenous opioids may also exhibit anti-inflammatory activities in the periphery, we examined the consequences of a peripheral opioid receptor blockade by naloxone-methiodide, a general opioid receptor antagonist unable to cross the blood-brain barrier, on the development of piroxicam-accelerated colitis in IL-10-deficient (IL-10-/-) mice. Here, we show that IL-10-deficient mice treated with piroxicam exhibited significant alterations of the intestinal barrier function, including permeability, inflammation-related bioactive lipid mediators, and mucosal CD4+ T lymphocyte subsets. Opioid receptor antagonization in the periphery had virtually no effect on colitis severity but significantly worsened epithelial cell apoptosis and intestinal permeability. Thus, although the endogenous opioid tone is not sufficient to reduce the severity of colitis significantly, it substantially contributes to the protection of the physical integrity of the epithelial barrier.

Opioid-Mediated HIV-1 Immunopathogenesis

Despite the ability of combination antiretroviral therapy to dramatically suppress viremia, the brain continues to be a reservoir of HIV-1 low-level replication. Adding further complexity to this is the comorbidity of drug abuse with HIV-1 associated neurocognitive disorders and neuroHIV. Among several abused drugs, the use of opiates is highly prevalent in HIV-1 infected individuals, both as an abused drug as well as for pain management. Opioids and their receptors have attained notable attention owing to their ability to modulate immune functions, in turn, impacting disease progression. Various cell culture, animal and human studies have implicated the role of opioids and their receptors in modulating viral replication and virus-mediated pathology both positively and negatively. Further, the combinatorial effects of HIV-1/HIV-1 proteins and morphine have demonstrated activation of inflammatory signaling in the host system. Herein, we summarized the current knowledge on the role of opioids on peripheral immunopathogenesis, viral immunopathogenesis, epigenetic profiles of the host and viral genome, neuropathogenesis of SIV/SHIV-infected non-human primates, blood-brain-barrier, HIV-1 viral latency, and viral rebound. Overall, this review provides recent insights into the role of opioids in HIV-1 immunopathogenesis. Graphical abstract.

Impact of perioperative pain management on cancer recurrence: an ASRA/ESRA special article

Cancer causes considerable suffering and 80% of advanced cancer patients experience moderate to severe pain. Surgical tumor excision remains a cornerstone of primary cancer treatment, but is also recognized as one of the greatest risk factors for metastatic spread. The perioperative period, characterized by the surgical stress response, pharmacologic-induced angiogenesis, and immunomodulation results in a physiologic environment that supports tumor spread and distant reimplantation.In the perioperative period, anesthesiologists may have a brief and uniquewindow of opportunity to modulate the unwanted consequences of the stressresponse on the immune system and minimize residual disease. This reviewdiscusses the current research on analgesic therapies and their impact ondisease progression, followed by an evidence-based evaluation of perioperativepain interventions and medications.

Effect of morphine and a low dose of ketamine on the T cells of patients with refractory cancer pain in vitro

The combination of morphine and ketamine is considered safe and efficacious in many patients. However, a considerable number of immunomodulatory effects have been reported to be produced by both morphine and ketamine. The aim of the present study was to assess the direct effect of morphine and a low dose of ketamine on the T cells of patients with refractory cancer pain in vitro. Venous blood was obtained from patients with refractory cancer pain and peripheral blood mononuclear cells were isolated using the Ficoll-Hypaque density gradient method. Anti-CD3 beads were used to isolate T cells by positive selection. Subsequently, the T cells were treated with vehicle, 200 ng/ml of morphine or 200 ng/ml of morphine + 100 ng/ml ketamine for 24 h, following which the cells were stimulated with anti-CD3 and anti-CD28. Flow cytometric analysis of CD3⁺ T cells, and interleukin (IL)-2 and interferon (IFN)-γ in the supernatant, reverse transcription-quantitative PCR analysis for the detection of IL-2 and IFN-γ and western blotting for the detection of p65 nuclear factor (NF)-κB were performed. In vitro, the CD4⁺ and CD8⁺ T cell counts, CD4⁺/CD8⁺ ratio, secretion of IL-2 and IFN-γ in the supernatant, mRNA expression levels of IL-2 and IFN-γ and expression of p65 NF-κB were significantly decreased following treatment with morphine and morphine + ketamine, compared with results in the control group (all P<0.05). However, there was no significant difference between treatment with morphine and that with morphine + ketamine. Treatment with morphine + ketamine in vitro decreased the immune functions of patients with refractory cancer pain, although the effect of treatment with morphine and a low dose of ketamine did not differ significantly from that with morphine treatment alone.

Unravelled facets of milk derived opioid peptides: a focus on gut physiology, fractures and obesity

Beyond being a source of key nutrients, bovine milk influences physiological functions by synthesising bioactive peptides during the process of digestion. Some of the claimed negative health outcomes associated with milk consumption, such as cardiovascular diseases and type 1 diabetes may be attributed to an opioid peptide, beta-casomorphin-7 (BCM-7), derived from A1 beta-casein. BCM-7 exerts its function by binding to the μ-opioid receptors in the body. It is hypothesised that activation of the μ-opioid receptors in the gut can alter gut microbial composition, impair gut barrier integrity and bile acid metabolism, in addition to increasing gastrointestinal transit time and gut inflammation. Further, it is hypothesised that BCM-7 may influence fractures and obesity via μ-opioid receptor pathways. In conclusion, it appears that BCM-7 might have multiple functions pertinent to human health; however, the evidence is limited and warrants further pre-clinical and clinical studies for hypothesis confirmation.

Morphine Potentiates Dysbiotic Microbial and Metabolic Shifts in Acute SIV Infection

Human Immunodeficiency Virus (HIV) pathogenesis has been closely linked with microbial translocation, which is believed to drive inflammation and HIV replication. Opioid drugs have been shown to worsen this symptom, leading to a faster progression of HIV infection to Acquired Immunodeficiency Syndrome (AIDS). The interaction of HIV and opioid drugs has not been studied at early stages of HIV, particularly in the gut microbiome where changes may precede translocation events. This study modeled early HIV infection by examining Simian Immunodeficiency Virus (SIV)-infected primates at 21 days or less both independently and in the context of opioid use. Fecal samples were analyzed both for 16S analysis of microbial populations as well as metabolite profiles via mass spectrometry. Our results indicate that changes are minor in SIV treated animals in the time points examined, however animals treated with morphine and SIV had significant changes in their microbial communities and metabolic profiles. This occurred in a time-independent fashion with morphine regardless of how long the animal had morphine in its system. Globally, the observed changes support that microbial dysbiosis is occurring in these animals at an early time, which likely contributes to the translocation events observed later in SIV/HIV pathogenesis. Additionally, metabolic changes were predictive of specific treatment groups, which could be further developed as a diagnostic tool or future intervention target to overcome and slow the progression of HIV infection to AIDS.

Effects of systemic and neuraxial morphine on the immune system

In the study, we tried to evaluate the effects of morphine injected through the systemic or neuraxial route on immune cell function and cytokine production in healthy women.In total, 29 paired samples of fresh peripheral blood were collected from healthy women who had been administered morphine for anesthetic analgesia through intravenous (IV), epidural, or spinal route postpartum. Their isolated peripheral blood mononuclear cells were mitogen-activated and stained with fluorochrome-conjugated anti-CD4, anti-CD8, anti-interleukin (IL)-2, and anti-interferon (IFN)-γ antibodies for flow cytometry, and the plasma levels of cytokines, including IL-6, IFN-α2, IL-10, IL-8, GM-CSF, and monocyte chemoattractant protein (MCP)-1, were measured through enzyme-linked immunosorbent assay.The results demonstrated that regardless of the administration route, morphine delivery slightly reduced IL-2 expression in CD4 cells after activation, and the same effect was not noted for CD8 cells. Intravenous or epidural morphine tended to reduce IFN-γ expression in CD8 cells. Spinal and IV morphine substantially increased IL-6 production, whereas epidural morphine hindered IL-10 and GM-CSF production. IV morphine injection reduced MCP-1 production in plasma. Compared with spinal morphine, IV or epidural morphine may more effectively inhibit the expression of various cytokines and thus affect immune response.All 3 routes of morphine injection tended to decrease IL-2 production by CD4 cells, whereas IV or epidural morphine injection showed lower IFN-γ production by CD8 cells. However, additional large-scale studies with longer follow-up durations are warranted.

Mobilization of CD4+ T lymphocytes in inflamed mucosa reduces pain in colitis mice: toward a vaccinal strategy to alleviate inflammatory visceral pain

T lymphocytes play a pivotal role in endogenous regulation of inflammatory visceral pain. The analgesic activity of T lymphocytes is dependent on their production of opioids, a property acquired on antigen activation. Accordingly, we investigated whether an active recruitment of T lymphocytes within inflamed colon mucosa via a local vaccinal strategy may counteract inflammation-induced visceral pain in mice. Mice were immunized against ovalbumin (OVA). One month after immunization, colitis was induced by adding 3% (wt/vol) dextran sulfate sodium into drinking water containing either cognate antigen OVA or control antigen bovine serum albumin for 5 days. Noncolitis OVA-primed mice were used as controls. Visceral sensitivity was then determined by colorectal distension. Oral administration of OVA but not bovine serum albumin significantly reduced dextran sulfate sodium-induced abdominal pain without increasing colitis severity in OVA-primed mice. Analgesia was dependent on local release of enkephalins by effector anti-OVA T lymphocytes infiltrating the inflamed mucosa. The experiments were reproduced with the bacillus Calmette-Guerin vaccine as antigen. Similarly, inflammatory visceral pain was dramatically alleviated in mice vaccinated against bacillus Calmette-Guerin and then locally administered with live Mycobacterium bovis. Together, these results show that the induction of a secondary adaptive immune response against vaccine antigens in inflamed mucosa may constitute a safe noninvasive strategy to relieve from visceral inflammatory pain.

T-lymphocyte-derived enkephalins reduce Th1/Th17 colitis and associated pain in mice

BACKGROUND

Endogenous opioids, including enkephalins, are fundamental regulators of pain. In inflammatory conditions, the local release of opioids by leukocytes at the inflammatory site inhibits nociceptor firing, thereby inducing analgesia. Accordingly, in chronic intestinal T_h1/T_h17-associated inflammation, enkephalins released by colitogenic CD4⁺ T lymphocytes relieve inflammation-induced visceral pain. The present study aims to investigate whether mucosal T-cell-derived enkephalins also exhibit a potent anti-inflammatory activity as described for exogenous opioid drugs in T_h1/T_h17-associated colitis.

METHODS

The anti-inflammatory effects of endogenous opioids were investigated in both T_h1/T_h17-associated (transfer of CD4⁺CD45RB^high T lymphocytes) and T_h2-associated (oxazolone) colitis models in mice. Inflammation-induced colonic damage and CD4⁺ T cell subsets were compared in mice treated or not treated with naloxone methiodide, a peripheral antagonist of opioid receptors. The anti-inflammatory activity of T-cell-derived enkephalins was further estimated by comparison of colitis severity in immunodeficient mice into which naïve CD4⁺CD45RB^high T lymphocytes originating from wild-type or enkephalin-knockout mice had been transferred.

RESULTS

Peripheral opioid receptor blockade increases the severity of T_h1/T_h17-induced colitis and attenuates T_h2 oxazolone colitis. The opposite effects of naloxone methiodide treatment in these two models of intestinal inflammation are dependent on the potency of endogenous opioids to promote a T_h2-type immune response. Accordingly, the transfer of enkephalin-deficient CD4⁺CD45RB^high T lymphocytes into immunodeficient mice exacerbates inflammation-induced colonic injury.

CONCLUSIONS

Endogenous opioids, including T-cell-derived enkephalins, promote a T_h2-type immune response, which, depending on the context, may either attenuate (T_h1/T_h17-associated) or aggravate (T_h2-associated) intestinal inflammation.

Morphine Suppresses T helper Lymphocyte Differentiation to Th1 Type Through PI3K/AKT Pathway

To investigate the effect of morphine on T helper lymphocyte differentiation and PI3K/AKT pathway mechanism, CD4+ lymphocytes were treated by phorbol-myristate-acetate (25 ng/ml) (PMA) plus ionomycin (1 μg/ml) in the presence of various concentrations of morphine (25, 50, 100, 200 ng/ml) for 4 h. Th1 and Th2 subsets, supernatant cytokines, and PI3K, AKT, and protein kinase C-theta (PKC-θ) levels were detected. The Th1 cell percentage, Th1-derived cytokines, and ratio of Th1/Th2 decreased in the presence of morphine in a concentration-dependent manner. However, Th2 cell percentage kept stable after morphine treatment. The phosphorylation of PI3K and AKT decreased, but the phosphorylation of PKC-θ did not change in the presence of morphine. The decreased percentage of Th1 cells and ratio of Th1/Th2 was recovered by naloxone concentration-dependently. Morphine can inhibit the differentiation of Th1 lymphocytes and decrease the ratio of Th1/Th2 via the pathway of PI3K/AKT. The effect can be inhibited by naloxone.

Clinical Toxicology and Its Relevance to Asthma and Atopy

Although both the prevalence of asthma and the prescription drug use, notably the opiate analgesic class, epidemics are increasing, there is a complex interplay between both disorders, with both protective and exacerbating factors involved in the effect of opiates on asthma pathogenesis and clinical severity. This review examines the airway effects, both immunologic and neurologic, of opiates, which may interact and result in protection or exacerbation of asthma.

TLR2 Involved in Naive CD4+ T Cells Rescues Stress-Induced Immune Suppression by Regulating Th1/Th2 and Th17

Stress, either physical or psychological, can have a dramatic impact on our immune system. There has been little progress, however, in understanding chronic stress-induced immunosuppression. Naive CD4+ T cells could modulate immune responses via differentiation to T helper (Th) cells. In this study, we showed that stress promotes the release of the Th1 cytokines interferon (IFN)-γ and tumor necrosis factor (TNF)-α, the Th2 cytokines interleukin (IL)-4 and IL-10 and the Th17 cytokine IL-17 of splenic naive CD4+ T cells. This suggests that stress promotes the differentiation of naive CD4+ T cells to Th1, Th2 and Th17 cells. Knockout strategies verified that TLR2 might modulate the differentiation of Th1/Th2 cells by inhibiting p38 mitogen-activated protein kinase (MAPK). Taken together, our data suggest that chronic stress induces immune suppression by targeting TLR2 and p38 MAPK in naive CD4+ T cells.

Inhibition of NF-κB by opioids in T cells

Opioids potently inhibit a number of physiological and pathophysiological effects such as pain and inflammation in the brain and the periphery. One of the targets of opioids mediating such effects is the proinflammatory transcription factor NF-κB. In neuronal cells, opioids inhibit this factor by inducing I-κB independently on calcium, involving the opioid-mediated activation of the transcription factor AP-1. However, when and how precisely NF-κB is modulated by opioids in T cells are unknown. By using the TNF-triggered, NF-κB-mediated induction of IL-8 mRNA in primary human T cells and Jurkat T cells, in this study we show that opioids inhibit NF-κB in T cells as well, but that the underlying mechanisms are different from those observed in neuronal cells. We found that stimulation of the T cells with opioids resulted in a significant inhibition of the TNF-triggered ubiquitination and degradation of I-κB. Additionally, an opioid-mediated induction of the deubiquitinating enzyme ubiquitin-specific protease 15 was observed, which is known to inhibit the NF-κB pathway by stabilizing I-κB. The induction of ubiquitin-specific protease 15 was dependent on calcium and the transcription factor NFAT. Activation of AP-1 and induction of I-κB in response to the opioids were not observed in the T cells. These results indicate that μ opioid receptors, which mediate the effects in both cell types, might be coupled to different effector cascades in the different cell types, which may then result in cell type-specific effects of the drugs.

μ opioid receptor agonist-selective regulation of interleukin-4 in T lymphocytes

Opioids are irreplaceable for the treatment of severe pain. However, opioid-induced immunomodulation affects therapies. Here we report that treatment of human T lymphocytes with the opioids fentanyl, methadone, loperamide and beta-endorphin resulted in a strong induction of the cytokine interleukin-4. In contrast, morphine and buprenorphine induced markedly and significantly lower levels of interleukin-4 mRNA and protein. These findings suggest agonist-biased μ opioid receptor signaling in T cells. In the future, better knowledge about agonist-specific immunomodulatory effects of opioids offers the possibility to select drugs for a therapy with more favorable and/or less detrimental side effects in immune cells.

The plasma levels of the cytokines in opium-addicts and the effects of opium on the cytokines secretion by their lymphocytes

The aim of this study was to evaluate the effects of opium addiction on the secretion of IL-4, IFN-γ, IL-6 and TGF-β under in vivo and in vitro conditions. The blood samples were collected and PBMCs were cultured in RPMI1640 with and without opium for 48 h. The levels of the cytokines were measured using ELISA technique. The results showed that plasma levels of IL-4 and IFN-γ were significantly lower and IL-6 and TGF-β were higher in plasma taken from opium-addicted subjects. The concentrations of all the cytokines in opium-addicted subjects in in vitro condition were significantly lower than the control group. Addicted subjects cultured lymphocytes significantly decrease secreted IL-4, IL-6 and TGF-β but not IFN-γ in response to being cultured with opium, where as IFN-γ was increased in controls. These results may explain the frequent microbial infections and an increased tumor incidence seen in addicted patients.

Substance abuse, HIV-1 and hepatitis

During the course of human immunodeficiency virus type 1 (HIV-1) disease, the virus has been shown to effectively escape the immune response with the subsequent establishment of latent viral reservoirs in specific cell populations within the peripheral blood (PB) and associated lymphoid tissues, bone marrow (BM), brain, and potentially other end organs. HIV-1, along with hepatitis B and C viruses (HBV and HCV), are known to share similar routes of transmission, including intravenous drug use, blood transfusions, sexual intercourse, and perinatal exposure. Substance abuse, including the use of opioids and cocaine, is a significant risk factor for exposure to HIV-1 and the development of acquired immune deficiency syndrome, as well as HBV and HCV exposure, infection, and disease. Thus, coinfection with HIV-1 and HBV or HCV is common and may be impacted by chronic substance abuse during the course of disease. HIV- 1 impacts the natural course of HBV and HCV infection by accelerating the progression of HBV/HCV-associated liver disease toward end-stage cirrhosis and quantitative depletion of the CD4+ T-cell compartment. HBV or HCV coinfection with HIV-1 is also associated with increased mortality when compared to either infection alone. This review focuses on the impact of substance abuse and coinfection with HBV and HCV in the PB, BM, and brain on the HIV-1 pathogenic process as it relates to viral pathogenesis, disease progression, and the associated immune response during the course of this complex interplay. The impact of HIV-1 and substance abuse on hepatitis virus-induced disease is also a focal point.

Expression and functions of μ-opioid receptors and cannabinoid receptors type 1 in T lymphocytes

Opioids and cannabinoids modulate T lymphocyte functions. Many effects of the drugs are mediated by μ-opioid receptor and cannabinoid receptor type 1 (CB1), respectively. These two receptors are strikingly similar with respect to their expression in T cells and the mechanisms by which they mediate modulation of T cell activity. Thus, μ-opioid receptors and CB1 not expressed in resting primary human and Jurkat T cells. However, in response to the cytokine IL-4, the epigenetic modifiers 5-aza-2'-deoxycytidine and trichostatin A, and activation of T cells, functional μ-opioid receptors and CB1 are induced. The induced receptors mediate inhibition of T cell signaling and, thereby, IL-2 production, a hallmark of activated T cells. Although coupled to inhibitory G proteins, μ-opioid receptors and CB1 produce a remarkable increase in cAMP levels in T cells stimulated with opioids and cannabinoids, which is a key mechanism for the inhibition of T cell signaling.

Anesthesia in patients with cancer disorders

PURPOSE OF REVIEW

Along with the increasing population of elderly people in developed countries, anesthesiologists have increasing opportunities to anesthetize cancer patients in their routine work. However, no guideline of anesthesia procedures for cancer patients is available even though guidelines of operative procedures have been formulated for different types of cancer. This review provides recent findings related to the optimal choice of anesthetics and adequate anesthesia management for cancer patients.

RECENT FINDINGS

The intrinsic weapon fighting cancer cells is competent immune cells, particularly CD4+ T helper 1-type cells, CD8+ cytotoxic T cells, and natural killer cells. However, surgical inflammation, some anesthetics, and inadvertent anesthesia management suppress these effector cells and induce suppressive immune cells, which render cancer patients susceptible to tumor recurrence and metastasis after surgery.

SUMMARY

Accumulated basic and clinical data suggest that total intravenous anesthesia with propofol, cyclooxygenase antagonists, and regional anesthesia can decrease negative consequences associated with perioperative immunosuppression. Volatile anesthesia, systemic morphine administration, unnecessary blood transfusions, intraoperative hypoxia, hypotension, hypothermia, and hyperglycemia should be avoided.

μ-opioid receptor-mediated alterations of allergen-induced immune responses of bronchial lymph node cells in a murine model of stress asthma

BACKGROUND

Psychological stress has a recognized association with asthma symptoms. Using a murine model of allergic asthma, we recently demonstrated the involvement of μ-opioid receptors (MORs) in the central nervous system in the stress-induced exacerbation of airway inflammation. However, the involvement of MORs on neurons and immunological alterations in the stress asthma model remain unclear.

METHODS

MOR-knockout (MORKO) mice that express MORs only on noradrenergic and adrenergic neurons (MORKO/Tg mice) were produced and characterized for stress responses. Sensitized mice inhaled antigen and were then subjected to restraint stress. After a second antigen inhalation, bronchoalveolar lavage cells were counted. Before the second inhalation, bronchial lymph node (BLN) cells and splenocytes from stressed and non-stressed mice were cultured with antigen, and cytokine levels and the proportions of T cell subsets were measured.

RESULTS

Stress-induced worsening of allergic airway inflammation was observed in wild-type and MORKO/Tg mice but not MORKO mice. In wild-type stressed mice, IFN-γ/IL-4 ratios in cell culture supernatants and the proportion of regulatory T cells in BLN cell populations were significantly lower than those in non-stressed mice. These differences in BLN cells were not observed between the stressed and non-stressed MORKO mice. Restraint stress had no effect on cytokine production or T cell subsets in splenocytes.

CONCLUSIONS

Restraint stress aggravated allergic airway inflammation in association with alterations in local immunity characterized by greater Th2-associated cytokine production and a reduced development of regulatory T cells, mediated by MORs.

Morphine induces splenocyte trafficking into the CNS

Opioids significantly alter functional responses of lymphocytes following activation. The opiate Morphine, alters the Th1 to Th2 response and modulates functional responses such as cytolytic activity and T-cell proliferation. Although there has been extensive research involving morphine's effects on lymphocytes, little is known about the effects morphine has on lymphocyte trafficking. The objective of the study was to use in vivo bioluminescent imaging to determine morphine's effect on the trafficking pattern of splenocytes systemically and into the CNS either in a naïve state or following a neuroinflammatory stimulus. A neuroinflammatory response was induced by intracerebrally administering a DNA IFN-γ DNA plasmid into morphine-dependent or placebo wildtype mice. Mice with or without a neurostimulus received adoptively transferred firefly luciferase transgenic splenocytes and imaged. Morphine dependence significantly altered the inherent ability of splenocytes to traffic into the spleen, and lead to non-directed chaotic trafficking throughout the animal, including into the CNS. The morphine-mediated effects on trafficking were blocked by the antagonist naltrexone. Morphine dependence intensified splenocyte infiltration into the CNS following neuroinflammation induced by IFN-γ gene transfer. The study precented determined that morphine severely altered the ability of non-activated splenocytes to home to the spleen, inducing extrasplenic trafficking thoughout the animal. In addition to altering the ability of naive splenocyte to traffic to the spleen, this study demonstrated that morphine profoundly exacerbated lymphocyte infiltration into the CNS following a neurostimulus.

Mechanisms of the inhibition of nuclear factor-κB by morphine in neuronal cells

Opioids potently modulate neuronal functions, for example, by regulating the activity of transcription factors. Here, we investigated the effect of morphine on the activity of the transcription factor nuclear factor κB (NF-κB). Establishing cellular models for our investigations, we demonstrated that NF-κB mediated the tumor necrosis factor (TNF)-induced transcription of the cannabinoid receptor type 1 gene in primary fetal striatal neurons from rats and the human neuroblastoma cell line SH SY5Y. The activity of NF-κB in these models was strongly inhibited by morphine, which was achieved by a marked up-regulation of the inhibitor of nuclear factor-κB (IκB). The opioid-induced up-regulation of IκB was dependent on the transcription factors NF-κB itself and activator protein-1 (AP-1). In fact, stimulation of the cells with morphine resulted in a transient activation of NF-κB and a strong induction of c-Fos, one of the constituents of AP-1. This resulted in IκB levels significantly exceeding the basal, constitutive levels of IκB. These data, together with experiments in which AP-1 and IκB were down-regulated by decoy oligonucleotides and siRNA, suggest that the morphine-induced activation of AP-1 and the subsequent overexpression of IκB are key factors in the inhibition of NF-κB by the drug. In contrast, stimulation of primary neurons from rats and SH SY5Y cells with TNF, which is a classic activator of NF-κB, resulted in a resynthesis of IκB, in which the basal levels of IκB were restored only but did not result in an activation of AP-1 and overexpression of IκB.

Sedation & immunomodulation

As the armamentarium for sedation in the critically ill expands, opportunities will develop to modulate the immune responses of patients by way of the direct immune and neural-immune interactions of the sedatives. Control of autonomic activity through the use of appropriate sedation may be critical in this matter. Likewise analgesic-based sedation, with increased opioid dosage, may not prove beneficial in the setting of infection; whether avoidance of morphine in preference for a fentanyl derivative will help is unclear. However, as the immune effects seem dependent on the m receptor, it is improbable that a significant difference would be uncovered. Similarly, the present evidence suggests benzodiazepines are deleterious in infection; further studies are required urgently to evaluate this evidence. As an alternative to benzodiazepine-based sedation, dexmedetomidine has shown a remarkable 70% mortality benefit in a small secondary analysis of septic patients from the MENDS trial. Further powered clinical studies should now be undertaken to investigate the potential benefit of the α2-adrenoceptor agonist in this setting, with comparisons with propofol.

Opioid drug abuse and modulation of immune function: consequences in the susceptibility to opportunistic infections

Infection rate among intravenous drug users (IDU) is higher than the general public, and is the major cause of morbidity and hospitalization in the IDU population. Epidemiologic studies provide data on increased prevalence of opportunistic bacterial infections such as TB and pneumonia, and viral infections such as HIV-1 and hepatitis in the IDU population. An important component in the intravenous drug abuse population and in patients receiving medically indicated chronic opioid treatment is opioid withdrawal. Data on bacterial virulence in the context of opioid withdrawal suggest that mice undergoing withdrawal had shortened survival and increased bacterial load in response to Salmonella infection. As the body of evidence in support of opioid dependency and its immunosuppressive effects is growing, it is imperative to understand the mechanisms by which opioids exert these effects and identify the populations at risk that would benefit the most from the interventions to counteract opioid immunosuppressive effects. Thus, it is important to refine the existing animal model to closely match human conditions and to cross-validate these findings through carefully controlled human studies. Better understanding of the mechanisms will facilitate the search for new therapeutic modalities to counteract adverse effects including increased infection rates. This review will summarize the effects of morphine on innate and adaptive immunity, identify the role of the mu opioid receptor in these functions and the signal transduction activated in the process. The role of opioid withdrawal in immunosuppression and the clinical relevance of these findings will also be discussed.

Influence of morphine on host immunity

Morphine is a widely used drug for analgesia and substance abuse. It has been accepted as a safe medication with great analgesic efficacy. Previous studies have reported that morphine is highly associated with the risk of immunosuppressive effects. Although the observed clinical effects suggest that morphine has the immunomodulatory capabilities, the mechanism of its action is still unclear. Here we review morphine on the bench to improve our understanding of the drug on the host immunity at the bedside. Studies of the effects of morphine on the innate and adaptive immune systems as well as immune responses are also discussed.

The role of morphine in regulation of cancer cell growth

Morphine is considered the "gold standard" for relieving pain and is currently one of the most effective drugs available clinically for the management of severe pain associated with cancer. In addition to its use in the treatment of pain, morphine appears to be important in the regulation of neoplastic tissue. Although morphine acts directly on the central nervous system to relieve pain, its activities on peripheral tissues are responsible for many of the secondary complications. Therefore, understanding the impact, other than pain control, of morphine on cancer treatment is extremely important. The effect of morphine on tumor growth is still contradictory, as both growth-promoting and growth-inhibiting effects have been observed. Accumulating evidence suggests that morphine can affect proliferation and migration of tumor cells as well as angiogenesis. Various signaling pathways have been suggested to be involved in these extra-analgesic effects of morphine. Suppression of immune system by morphine is an additional complication. This review provides an update on the influence of morphine on the growth and migration potential of tumor cells.

The influence of μ-opioid receptor agonist and antagonist peptides on peripheral blood mononuclear cells (PBMCs)

Milk is one of the main source of biologically-active peptides that may function as regulatory substances called food hormones. After passing the gut-blood barrier, the μ-opioid receptor agonist and antagonist peptides may become the new factors influencing various functions of the human organism. The aim of the conducted research was to determine the influence of μ-opioid receptor agonist peptides: human and bovine β-casomorphin-7 (h/bBCM-7) and antagonistic peptides: casoxin-6 and- D (CXN-6/D) on proliferation and cytokine secretion of human peripheral blood mononuclear cells (PBMCs). The PBMCs proliferation was measured by the use of the BrdU test, which assesses the DNA synthesis activity and the WST-1 test which assesses the activity of mitochondrial dehydrogenase enzymes. The influence of all the investigated peptides on secretion of IL-4, IL-8, IL-13 and IFN-γ was determined by the use of the ELISA tests. Incubating the cells with the peptides has not caused any changes to their enzymatic activity, which has been proved by a WST-1 test. When using a BrdU test, however, it has been observed that there appear changes to proliferation of PBMCs correlated to amounts of bromodeoxyuridine incorporated into the cellular DNA. Moreover, changes to secretion of IL-4 and IL-13 by the cells under the influence of agonists were detected, as well as changes to secretion of IFN-gamma under the influence of all the examined substances. The obtained results provide information on immunomodulatory effects of food-derived opioid peptides, which may be of clinical significance especially in the case of allergic diseases in newborns.

Morphine potentiates neuropathogenesis of SIV infection in rhesus macaques

Despite the advent of antiretroviral therapy, complications of HIV-1 infection with concurrent drug abuse are an emerging problem. Opiates are well known to modulate immune responses by preventing the development of cell-mediated immune responses. Their effect on the pathogenesis of HIV-1 infection however remains controversial. Using the simian immunodeficiency virus/macaque model of HIV pathogenesis, we sought to explore the impact of morphine on disease progression and pathogenesis. Sixteen rhesus macaques were divided into two groups; four were administered saline and 12 others morphine routinely. Both groups of animals were then inoculated with SIVmacR71/17E and followed longitudinally for disease pathogenesis. The morphine group (M+V) exhibited a trend towards higher mortality rates and retardation in weight gain compared to the virus-alone group. Interestingly, a subset of M+V animals succumbed to disease within weeks post-infection. These rapid progressors also exhibited a higher incidence of other end-organ pathologies. Despite the higher numbers of circulating CD4+ and CD8+ T cells in the M+V group, CD4/CD8 ratios between the groups remained unchanged. Plasma and CSF viral load in the M+V group was at least a log higher than the control group. Similarly, there was a trend toward increased virus build-up in the brains of M+V animals compared with controls. A novel finding of this study was the increased influx of infected monocyte/macrophages in the brains of M+V animals.

Morphine suppresses MHC-II expression on circulating B lymphocytes via activation of the HPA

Morphine has been shown to alter gene expression of the major histocompatibility complex, class II (MHC-II) in circulating rat immunocytes. Here, we demonstrate that a single morphine injection (10 mg/kg) reduces basal MHC-II protein expression on circulating B lymphocytes by 33%, while also impairing the ability of B lymphocytes to increase MHC-II upon interleukin-4 induction. As these data implicate opioids in the regulation of antigen presentation, studies were undertaken to examine the potential mechanisms through which morphine exerts this suppressive effect. Central injection studies utilized Tyr-D-Ala-Gly-(me) Phe-Gly-ol (DAMGO), an opioid receptor agonist, which mimicked morphine's effect on MHC-II, while D-Phe-Cys_Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP) pretreatment, prior to morphine, blocked the suppression of MHC-II. As central opioid receptor activation results in the activation of the hypothalamic-pituitary-adrenal axis, thereby, signaling increased circulating corticosterone levels, we examined whether MHC-II expression was suppressed after incubation with corticosterone at concentrations similar to those observed after morphine. Interestingly, corticosterone dramatically decreased basal MHC-II (88%) expression while completely preventing the induction of MHC-II. Additionally, MHC-II suppression was absent in morphine-treated adrenalectomized animals. Since prolonged morphine exposure has previously been shown to result in tolerance to both the steroidogenic and immunosuppressive effects of morphine, the effect of prolonged morphine exposure on MHC-II was also examined. Interestingly, MHC-II expression is no longer suppressed after chronic morphine, while morphine withdrawal results in both a renewed increase in circulating corticosterone levels and a renewed suppression of MHC-II in previously tolerant animals. Taken together, these data strongly implicate corticosterone in mediating the suppressive effects of morphine on circulating B-lymphocyte MHC-II expression.

Sedation & immunomodulation

The management of critically ill patients necessitates the use of sedatives and analgesics to provide patient comfort and cooperation. These drugs exert profound effects on all organ systems, not only the central nervous system, and this article describes the immunologic effects of the commonly used critical care sedatives: propofol, the benzodiazepines, opioids, and alpha(2)-adrenoceptor agonists. Benzodiazepines, opioids, and possibly even propofol worsen outcome in animal models of infection, whereas preliminary evidence suggests that the alpha(2)-adrenoceptor agonist, dexmedetomidine, may improve outcomes in the setting of infection. Given the burden of sepsis and secondary infections in critical care, choice of sedation may need to be carefully considered to preserve immune responses in critically ill patients.

[Opioid-induced pruritus. Mechanisms and treatment regimens]

Substantial progress has been achieved in recent years in research on the interaction between pain and pruritus. Over and above the known inhibition of pruritus by painful stimuli (e.g. scratching), a foundation for the explanation of opioid-induced pruritus was laid through the discovery of pruritus-specific neuronal processing channels. Although traditionally the degranulating effect of opioids on mast cells was assumed to be the essential mechanism, it is now clear that opioids can also induce itching at the spinal level. Neurons of the dorsal horn of the pain system inhibit spinal itch neurons. If this inhibition is weakened by opioids, the disinhibited itch neurons become active and mediate itching, without stimulation of the primary afferent peripheral nerves. Spinal triggering of itching is observed in particular by activation of mu-opioid receptors (mu-OR), while kappa-OR surprisingly suppress itch. The therapeutic implications of this interaction will be described.

Dopamine released by dendritic cells polarizes Th2 differentiation

A major neurotransmitter dopamine transmits signals via five different seven transmembrane G protein-coupled receptors termed D1-D5. It is now evident that dopamine is released from leukocytes and acts as autocrine or paracrine immune modulator. However, the role of dopamine for dendritic cells (DCs) and T(h) differentiation remains unclear. We herein demonstrate that human monocyte-derived dendritic cells (Mo-DCs) stored dopamine in the secretary vesicles. The storage of dopamine in Mo-DCs was enhanced by forskolin and dopamine D2-like receptor antagonists via increasing cyclic adenosine 3',5'-monophosphate (cAMP) formation. Antigen-specific interaction with naive CD4(+) T cells induced releasing dopamine-including vesicles from Mo-DCs. In naive CD4(+) T cells, dopamine dose dependently increased cAMP levels via D1-like receptors and shifts T-cell differentiation to T(h)2, in response to anti-CD3 plus anti-CD28 mAb. Furthermore, we demonstrated that dopamine D2-like receptor antagonists, such as sulpiride and nemonapride, induced a significant DC-mediated T(h)2 differentiation, using mixed lymphocyte reaction between human Mo-DCs and allogeneic naive CD4(+) T cells. When dopamine release from Mo-DCs is inhibited by colchicines (a microtubule depolymerizer), T-cell differentiation shifts toward T(h)1. These findings identify DCs as a new source of dopamine, which functions as a T(h)2-polarizing factor in DC-naive T-cell interface.

Opioid-induced immunosuppression

PURPOSE OF REVIEW

This review provides an overview of the immunological effects of commonly used analgesic opioid drugs with particular emphasis on human studies, with the final aim to highlight their potential clinical relevance.

RECENT FINDINGS

The immunomodulatory effects of morphine have been characterized in animal and human studies. Morphine decreases the effectiveness of several functions of both natural and acquired immunity, interfering with important intracellular pathways involved in immune regulation. Mainly from animal studies, however, it has emerged that not all opioids induce the same immunosuppressive effects and evaluating each opioid's profile is important for appropriate analgesic selection. The potent opioid fentanyl also exerts a relevant immunosuppression, while the partial agonist buprenorphine appears to have a more favourable immune profile. The impact of the opioid-mediated immune effects could be particularly dangerous in selective vulnerable populations, such as the elderly or immunocompromised patients.

SUMMARY

The impact of opioid drug treatment on immunity may be a new safety concern for the physician. Although many advances have been made in understanding the effects of opioid drugs on immune responses, their relevance is not completely clear. The scientific community must be aware that it is about time to perform well designed clinical studies in order to assess the importance of opioid-induced immune suppression.

Methadone ameliorates multiple-low-dose streptozotocin-induced type 1 diabetes in mice

Type 1 diabetes is an autoimmune disease characterized by inflammation of pancreatic islets and destruction of beta cells by the immune system. Opioids have been shown to modulate a number of immune functions, including T helper 1 (Th1) and T helper 2 (Th2) cytokines. The immunosuppressive effect of long-term administration of opioids has been demonstrated both in animal models and humans. The aim of this study was to determine the effect of methadone, a mu-opioid receptor agonist, on type 1 diabetes. Administration of multiple low doses of streptozotocin (STZ) (MLDS) (40 mg/kg intraperitoneally for 5 consecutive days) to mice resulted in autoimmune diabetes. Mice were treated with methadone (10 mg/kg/day subcutaneously) for 24 days. Blood glucose, insulin and pancreatic cytokine levels were measured. Chronic methadone treatment significantly reduced hyperglycemia and incidence of diabetes, and restored pancreatic insulin secretion in the MLDS model. The protective effect of methadone can be overcome by pretreatment with naltrexone, an opioid receptor antagonist. Also, methadone treatment decreased the proinflammatory Th1 cytokines [interleukin (IL)-1beta, tumor necrosis factor-alpha and interferon-gamma] and increased anti-inflammatory Th2 cytokines (IL-4 and IL-10). Histopathological observations indicated that STZ-mediated destruction of beta cells was attenuated by methadone treatment. It seems that methadone as an opioid agonist may have a protective effect against destruction of beta cells and insulitis in the MLDS model of type 1 diabetes.

Morphine withdrawal inhibits IL-12 induction in a macrophage cell line through a mechanism that involves cAMP

There are very few studies that examine the effects that morphine withdrawal has on immune functioning, and of these even fewer describe the mechanisms by which withdrawal brings about these changes. Our previous work demonstrated that morphine withdrawal contributed to Th cell differentiation by biasing cells toward the Th2 lineage. A major finding from these studies was that IL-12 was decreased following withdrawal, and it was concluded that this decrease may be a mechanism by which morphine withdrawal is mediating Th2 polarization. Therefore, it was the aim of the current studies to develop an in vitro model to examine the process of morphine withdrawal and to understand the signaling mechanisms that withdrawal may use to effect IL-12 production through the use of this model. It was demonstrated and concluded that morphine withdrawal may be effecting IL-12 production by increasing cAMP levels, which activates protein kinase A. Protein kinase A activation then prevents the phosphorylation and subsequent degradation of IkappaB, which in turn prevents translocation of the NF-kappaB p65 subunit to the nucleus to transactivate the IL-12 p40 gene, ultimately resulting in decreased IL-12 production following LPS stimulation.

T-cell receptor/CD28-mediated activation of human T lymphocytes induces expression of functional mu-opioid receptors

Opiates function as immunomodulators, partly by their effects on T cells. Opioids act via mu-, delta-, and kappa-opioid receptors, among which the mu-type is of particular interest, because morphine-like opioids preferentially bind to it. Here we report that mu-opioid receptor mRNA was induced after CD3/28-mediated activation of primary human T lymphocytes and Jurkat T cells, neither of which expresses the gene constitutively. Moreover, a reporter gene construct containing 2624 base pairs of the mu-opioid receptor promoter was transactivated by CD3/28 stimulation. Transcriptional induction of the mu-opioid receptor gene was mediated by activator protein-1 (AP-1), nuclear factor-kappaB, and nuclear factor of activated T cells (NFAT). NFAT was found to bind to three sequences of the mu-opioid receptor promoter, located at nucleotides -1064, -785, and -486. Although the -486 element is in close proximity to a putative AP-1 site, there was no evidence for a combined AP-1/NFAT site. Furthermore, we demonstrated that the induction of interleukin-2 mRNA and protein in activated T cells was inhibited by morphine in cells, in which mu-opioid receptors had been induced by CD3/28 monoclonal antibodies (mAbs), and that this effect was blocked by the mu-opioid receptor-specific antagonist D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH(2). CD3/28 mAb-induced interleukin-2 transcription was also inhibited by the opioids fentanyl and loperamide. This indicates that the induced mu-opioid receptor mRNA is translated into functional receptor protein. Furthermore, a mu-opioid receptor-enhanced green fluorescent protein-fusion protein was localized in membranes of Jurkat cells and internalized in response to [D-Ala(2),N-Me-Phe(4),Gly(5)-ol]-enkephalin but not morphine. In conclusion, these data emphasize the role of opioids in the modulation of T lymphocyte signaling.

The "T" in trauma: the helper T-cell response and the role of immunomodulation in trauma and burn patients

BACKGROUND

The immune system undergoes numerous changes after traumatic and burn injuries, including a down-regulation of the TH1 response and up-regulation of the TH2 response.

METHODS

The PubMed, Medline, and Ovid search engines were queried for relevant human studies. Bibliographies were also meticulously reviewed.

RESULTS

An interesting and potentially clinically relevant pattern of immune dysregulation exists after injury. The type 1 T-helper cell (TH1) response is suppressed as illustrated by diminished interleukin (IL)-2, interferon (IFN)-gamma, and IL-12 levels after major injury. The enhancement of the TH2 response is marked by elevated IL-10 and IL-4. Certain cytokine profiles, ratios, and polymorphisms may help identify patients at increased risk of systemic inflammatory response syndrome (SIRS), sepsis, multiple organ failure (MOF), and deep venous thrombosis. The most promising prognostic indicators to date are decreased production of the IL-12, elevated IL-10, soluble IL-2 receptor-a (sIL-2Ra), and IL-18 levels, IL-18 promoter polymorphisms, the IL-6:IL-10 ratio, and the degree of TH1 suppression as measured by diminished IL-2 and IFN-gamma. The Cytokine sections are subdivided into basic science, human studies, animal studies (when necessary), and directed therapeutics. The outcomes of sepsis, SIRS, or MOF are generally discussed together.

CONCLUSIONS

T-cell-specific immunologic changes occur after major injury. Identification of those TH1/TH2 cytokine profiles associated with worse prognosis may one day allow clinicians to risk stratify injured patients and identify those at increased risk of developing SIRS, sepsis, MOF, and deep venous thrombosis. Immune-targeted therapies may eventually serve as effective treatments in the acute setting to decrease morbidity and mortality, and to improve the management and prognosis of those patients at risk for developing postinjury complications.

Effect of morphine on the neuropathogenesis of SIVmac infection in Indian Rhesus Macaques

Morphine is known to prevent the development of cell-mediated immune (CMI) responses and enhance expression of the CCR5 receptor in monocyte macrophages. We undertook a study to determine the effect of morphine on the neuropathogenesis and immunopathogenesis of simian immunodeficiency virus (SIV) infection in Indian Rhesus Macaques. Hypothetically, the effect of morphine would be to prevent the development of CMI responses to SIV and to enhance the infection in macrophages. Sixteen Rhesus Macaques were divided into three experimental groups: M (morphine only, n = 5), VM (morphine + SIV, n = 6), and V (SIV only, n = 5). Animals in groups M and VM were given 2.5 mg/kg of morphine sulfate, four times daily, for up to 59 weeks. Groups VM and V were inoculated with SIVmacR71/17E 26 weeks after the beginning of morphine administration. Morphine prevented the development of enzyme-linked immunosorbent spot-forming cell CMI responses in contrast to virus control animals, all of which developed CMI. Whereas morphine treatment had no effect on viremia, cerebrospinal fluid viral titers or survival over the time course of the study, the drug was associated with a tendency for greater build-up of virus in the brains of infected animals. Histopathological changes in the brains of animals that developed disease were of a demyelinating type in the VM animals compared to an encephalitic type in the V animals. This difference may have been associated with the immunosuppressive effect of the drug in inhibiting CMI responses.

Comparative analysis of mu-opioid receptor expression in immune and neuronal cells

Morphine modulates neuronal and immune cell functions via mu-opioid receptors. In primary and Jurkat T cells, and Raji B cells mu-opioid receptor transcripts were detected only after stimulation of the cells with IL-4 or TNF-alpha. Moreover, the amount of the induced mu-opioid receptor mRNA in the immune cells was 15 to 200 times less than those in primary cortical and SH SY5Y neuronal cells. Nevertheless, mu-opioid receptor mRNA in immune cells is processed to functional receptors, as demonstrated by morphine-mediated phosphorylation of mitogen activated protein kinase, morphine-mediated up-regulation of IL-4 mRNA and coupling to adenylyl cyclase in Jurkat cells.

Transcriptional and Epigenetic Regulation of Interleukin-2 Gene in Activated T Cells by Morphine

Chronic morphine inhibits interleukin-2 (IL-2) at both the transcriptional and protein synthesis levels. The molecular mechanisms by which morphine decreases IL-2 are not fully understood. The production of IL-2 is tightly regulated by several transcription factors that bind to the IL-2 promoter. Herein, we show that chronic morphine treatment results in an increase in cAMP levels with a concurrent up-regulation of the cAMP inducible repressor inducible cAMP early repressor (ICER)/cAMP response element modulator (CREM) and down-regulation of p-cAMP-response element-binding protein (CREB) in activated T cells. Furthermore, ICER competes for p-CREB binding to the cAMP-responsive elements (CREs) site. This leads to the uncoupling of CBP/p300 thereby abrogating IL-2 transcription. Overexpression of either antisense CREM or CREB plasmid rescued morphine-induced inhibition of IL-2 promoter activity and protein production. In addition, we also found that chronic morphine treatment inhibited the acetylation and trimethylation of histones and decreased both DNA demethylation and accessibility of the IL-2 promoter. These findings suggest that chronic morphine treatment may function through both transcriptional and epigenetic mechanisms to inhibit IL-2 production.