Beta-endorphin concentrations in brain areas and peritoneal macrophages in rats susceptible and resistant to experimental allergic encephalomyelitis: a possible relationship between tumor necrosis factor alpha and opioids in the disease

Multiple Sclerosis and the Endogenous Opioid System

Multiple sclerosis (MS) is an autoimmune disease characterized by chronic inflammation, neuronal degeneration and demyelinating lesions within the central nervous system. The mechanisms that underlie the pathogenesis and progression of MS are not fully known and current therapies have limited efficacy. Preclinical investigations using the murine experimental autoimmune encephalomyelitis (EAE) model of MS, as well as clinical observations in patients with MS, provide converging lines of evidence implicating the endogenous opioid system in the pathogenesis of this disease. In recent years, it has become increasingly clear that endogenous opioid peptides, binding μ- (MOR), κ- (KOR) and δ-opioid receptors (DOR), function as immunomodulatory molecules within both the immune and nervous systems. The endogenous opioid system is also well known to play a role in the development of chronic pain and negative affect, both of which are common comorbidities in MS. As such, dysregulation of the opioid system may be a mechanism that contributes to the pathogenesis of MS and associated symptoms. Here, we review the evidence for a connection between the endogenous opioid system and MS. We further explore the mechanisms by which opioidergic signaling might contribute to the pathophysiology and symptomatology of MS.

Impact of Opioid Use in Hematological Malignancies: Clinical, Immunological and Concomitant Aspects

Opioid agents play a unique role in pain and symptom management for cancer patients. Research shows that opiate use, especially when associated with underlying cancer, has significant effects on hematological parameters. These changes may lead to greater risk for immunosuppression, tumor growth and progression of metastatic processes. The aim of this review is to explore the effects of opiates on various metabolic and biological processes, as well as the hematopoietic system, especially in cancer patients. Our findings demonstrate that the tumor-promoting effects of opiates remain contradictory, as both growth-promoting and anti-tumor effects have been observed. However, available data suggest that opiates can facilitate the proliferation and migration of tumor cells, and understanding of this process on cancer treatment is tremendously important.

Complementary and Alternative Therapies in Amyotrophic Lateral Sclerosis

Given the severity of their illness and lack of effective disease-modifying agents, it is not surprising that most patients with amyotrophic lateral sclerosis (ALS) consider trying complementary and alternative therapies. Some of the most commonly considered alternative therapies include special diets, nutritional supplements, cannabis, acupuncture, chelation, and energy healing. This article reviews these in detail. The authors also describe 3 models by which physicians may frame discussions about alternative therapies: paternalism, autonomy, and shared decision making. Finally, the authors review a program called ALSUntangled, which uses shared decision making to review alternative therapies for ALS.

The mechanism of effective electroacupuncture on T cell response in rats with experimental autoimmune encephalomyelitis

Previously, we demonstrated that electroacupuncture (EA) decreased lymphocyte infiltration into the spinal cords of rats presenting with experimental autoimmune encephalomyelitis (EAE), a disease model used in the study of multiple sclerosis (MS). The aim of this study was to characterize the effects of EA on the EAE. Female Lewis rats were divided into either CFA, EAE, EA, or injection with naloxone after electroacupuncture (NAL) groups. Electroacupuncture was administered every day for 21 days. To evaluate proliferation and apoptosis, lymphocytes from rats presenting with EAE were collected and cultured with β-endorphin. Immunohistochemisty, flow cytometry and radio-immunity methods were applied to detect the expression of β-endorphin. Results presented in this report demonstrate that the beneficial anti-inflammatory effects of EA on EAE were related to β-endorphin production that balances the Thl/Th2 and Th17/Treg responses. These results suggest that β-endorphin could be an important component in the development of EA-based therapies used for the treatment of EAE.

The effect of electroacupuncture on T cell responses in rats with experimental autoimmune encephalitis

Successive electroacupuncture (EA) stimulation on Zusanli ST36 acupoints of rats with experimental autoimmune encephalitis (EAE), which is an inflammatory disease mediated by autoreactive T cells, relieved disease severity, inhibited specific T cell proliferation and rebuilt the CD4+ T cell subset balance. In addition, EA-treated rats had significantly higher ACTH concentrations in vivo compared to untreated EAE rats. These results indicated that EA stimulation could relieve the severity of EAE by restoring balance to the Th1/Th2/Th17/Treg Th cell subset responses by stimulating the hypothalamus to increase ACTH secretion.

Suppression of IgE production and modulation of Th1/Th2 cell response by electroacupuncture in DNP-KLH immunized mice

Effects of electroacupuncture (EA) on Th1/Th2 cell response were investigated in BALB/c mice immunized intraperitoneally with 2,4-dinitrophenylated keyhole limpet protein (DNP-KLH). Successive electroacupuncture stimulation on the ST36 acupoint was performed just after immunization. Serum levels of antigen-specific IgE and total IgE were significantly decreased compared with non-acupunctured controls. Production of the Th2-specific cytokines IL-4 and IL-13 in the anti-CD3 mAb-activated splenocytes was significantly suppressed in ST36 electroacupunctured mice compared with non-acupunctured mice. These results imply that successive electroacupuncture on ST36 can decrease the serum level of antigen-specific IgE and total IgE by suppression of the Th2 lineage development.

Intramuscular electroporation with the pro-opiomelanocortin gene in rat adjuvant arthritis

Endogenous opioid peptides have an essential role in the intrinsic modulation and control of inflammatory pain, which could be therapeutically useful. In this study, we established a muscular electroporation method for the gene transfer of pro-opiomelanocortin (POMC) in vivo and investigated its effect on inflammatory pain in a rat model of rheumatoid arthritis. The gene encoding human POMC was inserted into a modified pCMV plasmid, and 0-200 microg of the plasmid-POMC DNA construct was transferred into the tibialis anterior muscle of rats treated with complete Freund's adjuvant (CFA) with or without POMC gene transfer by the electroporation method. The safety and efficiency of the gene transfer was assessed with the following parameters: thermal hyperalgesia, serum adrenocorticotropic hormone (ACTH) and endorphin levels, paw swelling and muscle endorphin levels at 1, 2 and 3 weeks after electroporation. Serum ACTH and endorphin levels of the group into which the gene encoding POMC had been transferred were increased to about 13-14-fold those of the normal control. These levels peaked 1 week after electroporation and significantly decreased 2 weeks after electroporation. Rats that had received the gene encoding POMC had less thermal hypersensitivity and paw swelling than the non-gene-transferred group at days 3, 5 and 7 after injection with CFA. Our promising results showed that transfer of the gene encoding POMC by electroporation is a new and effective method for its expression in vivo, and the analgesic effects of POMC cDNA with electroporation in a rat model of rheumatoid arthritis are reversed by naloxone.

The opioid antagonist naloxone induces a shift from type 2 to type 1 cytokine pattern in normal and skin-grafted mice

Opioid peptides affect different immune functions. We present evidence that these effects could be mediated by the modulation of Th1/Th2 cytokine production. The acute and chronic treatment with the opioid receptor antagonist naloxone decreased the production of IL-4 by splenocytes of C57BL/6 and Balb/cJ mice, that present a Th1/Th2 dominance, respectively, immunized with the protein antigen KLH. In contrast, IL-2 and IFN-gamma levels were increased after naloxone treatment. These results indicate that naloxone increases Th1 and decreases Th2 cytokine production. Moreover in C57BL/6 mice, naloxone treatment was able to accelerate skin-graft rejection, a Th1-mediated phenomenon, by increasing Th1 cytokine production. The effect of naloxone could be ascribed to the removal of the regulatory effects exerted by endogenous opioid peptides, which could activate Th2 and suppress Th1 cytokines.

The opioid antagonist naloxone induces a shift from Type 2 to Type 1 cytokine pattern in BALB/cJ mice

Opioid peptides affect different immune functions. We present evidence that these effects could be mediated by the modulation of TH1/TH2 cytokine production. BALB/cJ mice were immunized with 50 or 100 μg of the protein antigen keyhole-limpet hemocyanin (KLH), and treated acutely or chronically with the opioid antagonist naloxone. One and 2 weeks after immunization, the production of cytokines by splenocytes was evaluated by in vitro restimulation with KLH. The acute and chronic treatment with the opioid receptor antagonist naloxone decreased the production of interleukin (IL)–4 by splenocytes of BALB/cJ mice. In contrast, IL-2 and interferon-γ levels increased after naloxone treatment. Finally, the opioid antagonist diminished the serum immunoglobulin G anti–KLH antibody titers. These results suggest that naloxone increases TH1 and decreases TH2 cytokine production. The effect of naloxone could be ascribed to the removal of the regulatory effects exerted by endogenous opioid peptides, which could therefore activate TH2 and suppress TH1 cytokines.

Immune deviation following stress odor exposure: role of endogenous opioids

Olfactory cues can alter immune function. BALB/c mice exposed to odors produced by footshock stressed donor mice have increased antibody responses and increased splenic interleukin (IL)-4 production following immunization relative to recipients of odors from unstressed animals. Here we document that exposure to stress odors results in analgesia that is blocked by the non-selective opioid receptor antagonist naltrexone. The stress odor-induced increase in antigen-driven IL-4 and antibody is also blocked by oral administration of naltrexone. Thus, we provide evidence that immune deviation can occur following a psychosocial stressor, and that the deviation appears to be mediated by endogenous opioid production.

Hypothalamic beta-endorphin concentrations are decreased in animals models of autoimmune disease

Complex interactions between the neuroendocrine and the immune systems are present in autoimmune diseases. The central opioid peptide beta-endorphin (BE) has been shown to modulate peripheral immune responses in normal animals. In the present study we analyze the hypothalamic concentrations of this peptide in two models of spontaneous autoimmune disease, the MRL [corrected] lpr/lpr mouse, that develops a lupus-like autoimmune disease, and the obese strain (OS) chickens afflicted with spontaneous autoimmune thyroiditis. In both instances, hypothalamic concentrations of BE are significantly lower than normal controls. In MRL [corrected] lpr/lpr mice, BE is already lower at 1 month of age, when no clinical sign of the disease is yet present. Similarly, low levels of BE are observed in OS chickens before the onset of thyroiditis, i.e., already at the embryonic stage. Moreover, a further decrease of BE is observed in OS chickens in correspondence with the first signs of thyroid mononuclear infiltration. Considering the immunosuppressive effects exerted by central BE, these results are suggestive of the fact that in autoimmune disease prone animals the low hypothalamic concentrations may be one of several factors predisposing for the development of autoimmune disease.