Exogenous and endogenous opioids as biological response modifiers

Myelin regulatory factor is a target of individual and interactive effects of HIV-1 Tat and morphine in the striatum and pre-frontal cortex

HIV-associated neurocognitive disorders (HAND) remain pervasive even with increased efficacy/use of antiretroviral therapies. Opioid use/abuse among HIV + individuals is documented to exacerbate CNS deficits. White matter (WM) alterations, including myelin pallor, and volume/structural alterations detected by diffusion tensor imaging are common observations in HIV + individuals, and studies in non-human primates suggest that WM may harbor virus. Using transgenic mice that express the HIV-1 Tat protein, we examined in vivo effects of 2-6 weeks of Tat and morphine exposure on WM using genomic and biochemical methods. RNA sequencing of striatal tissue at 2 weeks revealed robust changes in mRNAs associated with oligodendrocyte precursor populations and myelin integrity, including those for transferrin, the atypical oligodendrocyte marker N-myc downstream regulated 1 (Ndrg1), and myelin regulatory factor (Myrf/Mrf), an oligodendrocyte-specific transcription factor with a significant role in oligodendrocyte differentiation/maturation. Western blots conducted after 6-weeks exposure in 3 brain regions (striatum, corpus callosum, pre-frontal cortex) revealed regional differences in the effect of Tat and morphine on Myrf levels, and on levels of myelin basic protein (MBP), whose transcription is regulated by Myrf. Responses included individual and interactive effects. Although baseline and post-treatment levels of Myrf and MBP differed between brain regions, post-treatment MBP levels in striatum and pre-frontal cortex were compatible with changes in Myrf activity. Additionally, the Myrf regulatory ubiquitin ligase Fbxw7 was identified as a novel target in our model. These results suggest that Myrf and Fbxw7 contribute to altered myelin gene regulation in HIV.

Opioid and neuroHIV Comorbidity - Current and Future Perspectives

With the current national opioid crisis, it is critical to examine the mechanisms underlying pathophysiologic interactions between human immunodeficiency virus (HIV) and opioids in the central nervous system (CNS). Recent advances in experimental models, methodology, and our understanding of disease processes at the molecular and cellular levels reveal opioid-HIV interactions with increasing clarity. However, despite the substantial new insight, the unique impact of opioids on the severity, progression, and prognosis of neuroHIV and HIV-associated neurocognitive disorders (HAND) are not fully understood. In this review, we explore, in detail, what is currently known about mechanisms underlying opioid interactions with HIV, with emphasis on individual HIV-1-expressed gene products at the molecular, cellular and systems levels. Furthermore, we review preclinical and clinical studies with a focus on key considerations when addressing questions of whether opioid-HIV interactive pathogenesis results in unique structural or functional deficits not seen with either disease alone. These considerations include, understanding the combined consequences of HIV-1 genetic variants, host variants, and μ-opioid receptor (MOR) and HIV chemokine co-receptor interactions on the comorbidity. Lastly, we present topics that need to be considered in the future to better understand the unique contributions of opioids to the pathophysiology of neuroHIV.

Graphical Abstract

Possible Molecular Mediators Involved and Mechanistic Insight into Fibromyalgia and Associated Co-morbidities

Fibromyalgia is a chronic complex syndrome of non-articulate origin characterized by musculoskeletal pain, painful tender points, sleep problems and co-morbidities including depression, migraine. The etiopathogenesis of fibromyalgia is complex, variable and remains inconclusive. The etiological factors that have been defined include stress, genetic predisposition and environmental components. As per the reports of the American College of Rheumatology (ACR) the prevalence of fibromyalgia varies from 2 to 22% among the general population with poor diagnostic features primarily pain. Fibromyalgia encompasses a spectrum of co-morbid conditions with multifarious pathogenesis. The highly prevalent manifestations of fibromyalgia include heterogeneous pain and aches. Biochemical and neurobiological elements of fibromyalgia include neurotransmitters, hypothalamic pituitary adrenal axis (HPA axis), inflammatory cytokines, monoaminergic pathway, opioid peptides, sex hormones, nerve growth factor (NGF) and local free radical insult. An imbalance in the serotonergic system is the major underlying etiological factor that has been explored most widely. Owing to complex interplay of diverse pathophysiological pathways, overlapping co-morbidities such as depression have been clinically observed. Therapeutic management of fibromyalgia involves both non pharmacological and pharmacological measures. The current review presents various dysregulations and their association with symptoms of fibromyalgia along with their underlying neurobiological aspects.

Perioperative epidural use and survival outcomes in patients undergoing primary debulking surgery for advanced ovarian cancer

OBJECTIVE

Epidurals are associated with improved outcomes in some solid tumors, presumably due to their effect on surgical stress response. There are limited data on the prognostic significance of epidural anesthesia in patients undergoing primary debulking surgery (PDS) for advanced ovarian cancer. We sought to assess the impact of epidural anesthesia on the survival outcomes of patients undergoing PDS for advanced ovarian cancer.

METHODS

In this retrospective study, consecutive patients with stage IIIB-IV epithelial ovarian, fallopian tube, or peritoneal carcinoma who underwent PDS at our institution from 01/2005-12/2013 were identified. Progression-free survival (PFS) and overall survival (OS) with regard to epidural use were analyzed.

RESULTS

Of 648 patients, 435 received an epidural and 213 did not. Patients in the former group were more likely to have higher stage disease (stage IV disease, 26% vs. 16%, respectively; P = .005), carcinomatosis (87% vs. 80%, respectively; P = .027), and bulky upper abdominal disease (66% vs. 58%, respectively; P = .046). Complete gross resection was achieved in 48% and 32%, respectively (P < .001). For the epidural vs. non-epidural groups, median PFS was 20.8 months and 13.9 months, respectively (P = .021); median OS was 62.4 months and 41.9 months, respectively (P < .001). After controlling for confounding factors, including residual disease, epidural use was independently associated with a decreased risk of progression (HR = 1.327; 95% CI, 1.066-1.653) and death (HR = 1.588; 95% CI, 1.224-2.06).

CONCLUSIONS

Perioperative epidural use was independently associated with improved PFS and OS in these patients. Epidural anesthesia at the time of PDS may be warranted in this setting.

Morphine Tolerance and Physical Dependence Are Altered in Conditional HIV-1 Tat Transgenic Mice

Despite considerable evidence that chronic opiate use selectively affects the pathophysiologic consequences of human immunodeficiency virus type 1 (HIV-1) infection in the nervous system, few studies have examined whether neuro-acquired immune deficiency syndrome (neuroAIDS) might intrinsically alter the pharmacologic responses to chronic opiate exposure. This is an important matter because HIV-1 and opiate abuse are interrelated epidemics, and HIV-1 patients are often prescribed opiates as a treatment of HIV-1-related neuropathic pain. Tolerance and physical dependence are inevitable consequences of frequent and repeated administration of morphine. In the present study, mice expressing HIV-1 Tat in a doxycycline (DOX)-inducible manner [Tat(+)], their Tat(-) controls, and control C57BL/6 mice were chronically exposed to placebo or 75-mg morphine pellets to explore the effects of Tat induction on morphine tolerance and dependence. Antinociceptive tolerance and locomotor activity tolerance were assessed using tail-flick and locomotor activity assays, respectively, and physical dependence was measured with the platform-jumping assay and recording of other withdrawal signs. We found that Tat(+) mice treated with DOX [Tat(+)/DOX] developed an increased tolerance in the tail-flick assay compared with control Tat(-)/DOX and/or C57/DOX mice. Equivalent tolerance was developed in all mice when assessed by locomotor activity. Further, Tat(+)/DOX mice expressed reduced levels of physical dependence to chronic morphine exposure after a 1-mg/kg naloxone challenge compared with control Tat(-)/DOX and/or C57/DOX mice. Assuming the results seen in Tat transgenic mice can be generalized to neuroAIDS, our findings suggest that HIV-1-infected individuals may display heightened analgesic tolerance to similar doses of opiates compared with uninfected individuals and show fewer symptoms of physical dependence.

Sensitization of enteric neurons to morphine by HIV-1 Tat protein

BACKGROUND

Gastrointestinal (GI) dysfunction is a major cause of morbidity in acquired immunodeficiency syndrome (AIDS). HIV-1-induced neuropathogenesis is significantly enhanced by opiate abuse, which increases proinflammatory chemokine/cytokine release, the production of reactive species, glial reactivity, and neuronal injury in the central nervous system. Despite marked interactions in the gut, little is known about the effects of HIV-1 in combination with opiate use on the enteric nervous system.

METHODS

To explore HIV-opiate interactions in myenteric neurons, the effects of Tat ± morphine (0.03, 0.3, and 3 μM) were examined in isolated neurons from doxycycline- (DOX-) inducible HIV-1 Tat(1-86) transgenic mice or following in vitro Tat 100 nM exposure (>6 h).

KEY RESULTS

Current clamp recordings demonstrated increased neuronal excitability in neurons of inducible Tat(+) mice (Tat+/DOX) compared to control Tat-/DOX mice. In neurons from Tat+/DOX, but not from Tat-/DOX mice, 0.03 μM morphine significantly reduced neuronal excitability, fast transient and late long-lasting sodium currents. There was a significant leftward shift in V(0.5) of inactivation following exposure to 0.03 μM morphine, with a 50% decrease in availability of sodium channels at -100 mV. Similar effects were noted with in vitro Tat exposure in the presence of 0.3 μM morphine. Additionally, GI motility was significantly more sensitive to morphine in Tat(+) mice than Tat(-) mice.

CONCLUSIONS & INFERENCES

Overall, these data suggest that the sensitivity of enteric neurons to morphine is enhanced in the presence of Tat. Opiates and HIV-1 may uniquely interact to exacerbate the deleterious effects of HIV-1-infection and opiate exposure on GI function.

Morphine efficacy is altered in conditional HIV-1 Tat transgenic mice

Opiate abuse reportedly can exaggerate complications of human immunodeficiency virus type-1 (HIV-1) infection in the central nervous system (CNS), while opiate drugs are often indicated in the treatment of HIV-1-related neuropathic pain. Despite this quandary, few studies have assessed the relationship between the duration or extent of HIV-1 infection and the intrinsic neurobehavioral responsiveness to opioids. To address this problem, doxycycline (DOX)-inducible HIV-Tat(1-86) transgenic mice were used as a model for HIV-1-associated neurocognitive disorders, which permitted the regulation of Tat exposure and duration. The effects of continuous Tat induction on the activity of morphine were examined at weekly intervals using standard behavioral assays for nociception and motor function. In the spinal cord, Tat mRNA levels did not increase until the second and third weeks following induction, which corresponded to a significant loss of morphine antinociception as assessed in the tail-flick test. Alternatively, in the striatum, sustained increases in Tat mRNA expression during the second week of induction coincided with significant decreases in rotarod performance and interactions with morphine. Importantly, the behavioral effects of morphine differed depending on the timing and location of Tat expression, with increases in Tat transcript levels in the spinal cord and striatum corresponding to significant alterations in morphine-dependent nociception and rotarod performance, respectively. Assuming Tat levels contribute to the clinical manifestations of HIV-1, the results suggest that regional differences in viral load and opioid phenotype might influence the nature and degree that opiate responsiveness is altered in HIV-1-infected individuals.

Morphine and gp120 toxic interactions in striatal neurons are dependent on HIV-1 strain

A rigorously controlled, cell culture paradigm was used to assess the role of HIV-1 gp120 ± morphine in mediating opioid-HIV interactive toxicity in striatal neurons. Computerized time-lapse microscopy tracked the fate of individual neurons co-cultured with mixed-glia from mouse striata during opioid and gp120 exposure. Subpopulations of neurons and astroglia displayed μ-opioid receptor, CXCR4, and CCR5 immunoreactivity. While gp120 alone was or tended to be neurotoxic irrespective of whether X4-tropic gp120(IIIB), R5-tropic gp120(ADA), or dual-tropic gp120(MN) was administered, interactive toxicity with morphine differed depending on HIV-1 strain. For example, morphine only transiently exacerbated gp120(IIIB)-induced neuronal death; however, in combination with gp120(MN), morphine caused sustained increases in the rate of neuronal death compared to gp120(MN) alone that were prevented by naloxone. Alternatively, gp120(ADA) significantly increased the rate of neuron death, but gp120(ADA) toxicity was unaffected by morphine. The transient neurotoxic interactions between morphine and gp120(IIIB) were abrogated in the absence of glia suggesting that glia contribute significantly to the interactive pathology with chronic opiate abuse and neuroAIDS. To assess how mixed-glia might contribute to the neurotoxicity, the effects of morphine and/or gp120 on the production of reactive oxygen species (ROS) and on glutamate buffering were examined. All gp120 variants, and to a lesser extent morphine, increased ROS and/or decreased glutamate buffering, but together failed to show any interaction with morphine. Our findings indicate that HIV-1 strain-specific differences in gp120 are critical determinants in shaping both the timing and pattern of neurotoxic interactions with opioid drugs.

Fractalkine/CX3CL1 protects striatal neurons from synergistic morphine and HIV-1 Tat-induced dendritic losses and death

BACKGROUND

Fractalkine/CX3CL1 and its cognate receptor CX3CR1 are abundantly expressed in the CNS. Fractalkine is an unusual C-X3-C motif chemokine that is important in neuron-microglial communication, a co-receptor for HIV infection, and can be neuroprotective. To assess the effects of fractalkine on opiate-HIV interactive neurotoxicity, wild-type murine striatal neurons were co-cultured with mixed glia from the striata of wild-type or Cx3cr1 knockout mice ± HIV-1 Tat and/or morphine. Time-lapse digital images were continuously recorded at 20 min intervals for up to 72 h using computer-aided microscopy to track the same cells repeatedly.

RESULTS

Co-exposure to Tat and morphine caused synergistic increases in neuron death, dendritic pruning, and microglial motility as previously reported. Exogenous fractalkine prevented synergistic Tat and morphine-induced dendritic losses and neuron death even though the inflammatory mediator TNF-α remained significantly elevated. Antibody blockade of CX3CR1 mimicked the toxic effects of morphine plus Tat, but did not add to their toxicity; while fractalkine failed to protect wild-type neurons co-cultured with Cx3cr1-/--null glia against morphine and Tat toxicity. Exogenous fractalkine also normalized microglial motility, which is elevated by Tat and morphine co-exposure, presumably limiting microglial surveillance that may lead to toxic effects on neurons. Fractalkine immunofluorescence was expressed in neurons and to a lesser extent by other cell types, whereas CX3CR1 immunoreactivity or GFP fluorescence in cells cultured from the striatum of Cx3cr1-/- (Cx3cr1GFP/GFP) mice were associated with microglia. Immunoblotting shows that fractalkine levels were unchanged following Tat and/or morphine exposure and there was no increase in released fractalkine as determined by ELISA. By contrast, CX3CR1 protein levels were markedly downregulated.

CONCLUSIONS

The results suggest that deficits in fractalkine-CX3CR1 signaling contribute to the synergistic neurotoxic effects of opioids and Tat. Importantly, exogenous fractalkine can selectively protect neurons from the injurious effects of chronic opioid-HIV-1 Tat co-exposure, and this suggests a potential therapeutic course for neuroAIDS. Although the cellular mechanisms underlying neuroprotection are not certain, findings that exogenous fractalkine reduces microglial motility and fails to protect neurons co-cultured with Cx3cr1-/- mixed glia suggest that fractalkine may act by interfering with toxic microglial-neuron interactions.

The effect of opioid receptor blockade on the neural processing of thermal stimuli

The endogenous opioid system represents one of the principal systems in the modulation of pain. This has been demonstrated in studies of placebo analgesia and stress-induced analgesia, where anti-nociceptive activity triggered by pain itself or by cognitive states is blocked by opioid antagonists. The aim of this study was to characterize the effect of opioid receptor blockade on the physiological processing of painful thermal stimulation in the absence of cognitive manipulation. We therefore measured BOLD (blood oxygen level dependent) signal responses and intensity ratings to non-painful and painful thermal stimuli in a double-blind, cross-over design using the opioid receptor antagonist naloxone. On the behavioral level, we observed an increase in intensity ratings under naloxone due mainly to a difference in the non-painful stimuli. On the neural level, painful thermal stimulation was associated with a negative BOLD signal within the pregenual anterior cingulate cortex, and this deactivation was abolished by naloxone.

Evaluation of morphine effect on tumour angiogenesis in mouse breast tumour model, EATC

Breast cancer is the leading cause of death among women, and morphine is used to relieve the pain of patients with cancer. The data on the effects of morphine on tumour growth and angiogenesis are contradictory. We determined in mouse breast cancer model whether analgesic doses of morphine would affect tumour angiogenesis, and then the correlation between microvessel density (MVD), Doppler sonography (DS) and 99mTc-Tetrofosmin (TF) uptake. Ehrlich ascites tumour cell xenografts, Pgp-negative tumour were divided into two groups: (a) Morphine sulphate [0.714 mg/kg/day (equivalent to 50 mg per day for a 70 kg human)], (b) no-morphine. For the determination of angiogenesis in mice tumour tissue, TF scintigraphy, microvessel density and DS were done. MVD was significantly different between groups (49.4±1.8 vs. 41.8±1.9, morphine and no-morphine groups, respectively, P<0.001). A strong correlation was found between late uptakes of mass at scintigraphy and degree of angiogenesis in histopathologic examination (r=0.52, P<0.01). There was statistically significant inverse correlation between degree of angiogenesis in histopathologic examination and washout ratio of TF (r=0.40, P<0.05). The higher values for angiogenesis are related to higher TF reuptake. There was no statistically significant correlation between DS and TF. A strong correlation was found between MVD and grade of DS (r=0.51, P<0.01). Our preclinical mice study indicates that morphine at clinically relevant doses stimulates angiogenesis, and angiogenesis triggered of morphine is demonstrated with MVD and DS, but not TF. However, uptake and washout of TF are compared with immunohistochemically assessed morphine-stimulated angiogenesis in tumour tissue.

Down-regulation of c-Cbl by morphine accounts for persistent ERK1/2 signaling in delta-opioid receptor-expressing HEK293 cells

Opioids display ligand-specific differences in the time course of ERK1/2 signaling. Whereas full agonists, like etorphine, induce only transient activation of ERK1/2, the partial agonist morphine mediates persistent stimulation of mitogenic signaling. Here we report that in stably delta-opioid receptor (DOR)-expressing HEK293 (HEK/DOR) cells, the transient nature of etorphine-induced ERK1/2 signaling is due to desensitization of epidermal growth factor (EGF) receptor-mediated activation of the Ras/Raf-1/ERK1/2 cascade. Desensitization of ERK1/2 activity by etorphine is associated with down-regulation of EGF receptors, an effect mediated by the ubiquitin ligase c-Cbl. In contrast, chronic morphine treatment failed to desensitize EGF receptors, resulting in unimpeded ERK1/2 signaling. The failure of morphine to desensitize ERK1/2 signaling is mediated by persistent activation of c-Src, which induces degradation of c-Cbl. The role of c-Src in opioid-specific ERK1/2 signaling is further demonstrated by pretreatment of the cells with PP2 and SKI-I as well as overexpression of a dominant negative c-Src mutant (c-Src(dn)) or a c-Src-resistant c-Cbl mutant (CblY3F), both of which facilitate desensitization of ERK1/2 signaling by morphine. Conversely, overexpression of c-Src as well as down-regulation of c-Cbl by small interfering RNA results in persistent etorphine-induced stimulation of ERK1/2 activity. Subcellular fractionation experiments finally attributed the ability of morphine to persistently activate c-Src to its redistribution from Triton X-100-insensitive membrane rafts to DOR and EGF receptor containing high density membrane compartments implicated in ERK1/2 signaling. These results demonstrate that agonist-specific differences in the temporal and spatial pattern of c-Src activation determine the kinetics of DOR-mediated regulation of ERK1/2 signaling.

Neuronal adaptations, neuroendocrine and immune correlates of heroin self-administration

Opioid receptor-mediated action in the central nervous system (CNS) has been consistently shown to trigger changes in the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS) and suppress a variety of parameters of immune function in investigator-delivered paradigms. Overwhelming evidence supports the concept that the CNS undergoes numerous and complex neuronal adaptive changes in addicts, and in animal models of heroin addiction as a result of the training of drug stimuli to serve as reinforcers, altering the function of individual neurons and the larger neural circuits within which the neurons operate. Taken together, these advances suggest that since plastic neuronal changes occur in drug addiction and related animal model paradigms, profiles of neuroendocrine and immune function would differ in a rat model of heroin self-administration compared to passive infusion of drug. Self-administration of heroin induces neuronal circuitry adaptations in specific brain regions that may be related to alterations in neuroendocrine and T lymphocyte function also observed. Animals self-administering (SA) heroin exhibit increased mu-opioid receptor agonist ([D-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin (DAMGO))-stimulated guanosine-5'-O-(gamma-thio)-triphosphate ([(35)S]GTPgammaS) binding in the anterior hypothalamus (50% and 33%) and rostral medial thalamus (33% and 36%) compared with control animals receiving identical non-contingent injections of yoked-heroin (YH) or yoked-saline (YS), respectively. No changes in agonist-stimulated G-protein sensitization were observed in 14 other brain regions studied. No changes in mu-opioid receptor density, ((3)H-DAMGO binding) were seen in all brain regions examined. The neuronal changes in SA animals were correlated with elevated adrenocorticotrophic hormone (ACTH) (64% and 104%) and glucocorticoid production (198% and 79%) compared with YH and YS groups, respectively. Neuroendocrine adaptive changes in SA animals were associated with thymic hypoplasia. Splenic T lymphocytes from animals that had self-administered heroin showed a profoundly reduced ability to proliferate in response to concanavalin A (50% and 48% compared with YH and YS controls, respectively; Fig. 1A), or a monoclonal antibody (R73) to the CD3/T-cell receptor complex (anti-TCR) plus IL-2 (55% and 59% compared with YH and YS controls, respectively; Fig. 1B). Self-administration of heroin selectively alters T lymphocyte function, as no effects on natural killer cell activity or macrophage functions were observed. These findings may have relevance to the acquisition and documented increased incidence of infectious diseases, including HIV, in heroin addicts, due to a pre-existing T-cell immunodeficient state.

Morphine causes rapid increases in glial activation and neuronal injury in the striatum of inducible HIV-1 Tat transgenic mice

HIV encephalitis (HIVE) is accompanied by brain inflammation, leukocyte infiltration, and glial activation, and HIV patients who abuse opiates are more likely to develop HIVE. To better understand how opiates could alter HIV-related brain inflammation, the expression of astrocyte (GFAP immunoreactivity) and macrophage/microglial (F4/80 or Mac1 immunoreactivity) markers in the striatum, and the percentage of 3-nitrotyrosine (3-NT) positive macrophages/microglia, was determined following a 2-day exposure to morphine (5 mg/kg/day via time-release, subcutaneous implant) and doxycycline in GFAP-driven, doxycycline-inducible HIV-1 Tat transgenic mice. Data show that both morphine and Tat induction via doxycycline increased astrocyte activation, with significant additive increases achieved with combined morphine and doxycycline exposure. By contrast, combined Tat induction and morphine exposure, but neither manipulation alone, significantly increased the proportion of macrophages/microglia present in the striatum of transgenic mice, although morphine exposure was necessary to elevate 3-NT co-detection in Mac1-positive macrophages/microglia. Finally, Tat induction increased the percentage of neurons expressing active caspase-3, and this was even more significantly elevated by co-administration of morphine. In spite of elevations in caspase-3, neuronal TUNEL reactivity was unchanged in all groups, even after 10 days of Tat induction. Importantly, co-administration of naltrexone completely antagonized the effects of morphine. These findings indicate that morphine rapidly and significantly increases the activation of astrocytes and macrophages/microglia in the brains of inducible Tat transgenic mice, supporting the theory that early inflammatory changes in glia could underlie the development of HIVE in opiate-abusing AIDS patients.

CCL5/RANTES gene deletion attenuates opioid-induced increases in glial CCL2/MCP-1 immunoreactivity and activation in HIV-1 Tat-exposed mice

To assess the role of CC-chemokine ligand 5 (CCL5)/RANTES in opiate drug abuse and human immunodeficiency virus type 1 (HIV-1) comorbidity, the effects of systemic morphine and intrastriatal HIV-1 Tat on macrophage/microglial and astroglial activation were assessed in wild-type and CCL5 knockout mice. Mice were injected intrastriatally with vehicle or Tat and assessed after 7 days. Morphine was administered to some Tat-injected mice via time-release implant (5 mg/day, s.c. for 5 days) starting at 2 days post injection. Glial activation was significantly reduced in CCL5(-/-) compared to wild-type mice at 7 days following combined Tat and morphine exposure. Moreover, the percentage of 3-nitrotyrosine immunopositive macrophages/microglia was markedly reduced in CCL5(-/-) mice injected with Tat +/- morphine compared to wild-type counterparts, suggesting that CCL5 contributes to nitrosative stress in HIV-1 encephalitis. In CCL5(-/-) mice, the reductions in Tat +/- morphine-induced gliosis coincided with significant declines in the proportion of CCL2/MCP-1-immunoreactive astrocytes and macrophages/microglia compared to wild-type counterparts. In knockout mice, neither Tat alone nor in combination with morphine increased the proportion of CCL2-immunoreactive astrocytes above percentages seen in vehicle-injected controls. Macrophages/microglia differed showing modest, albeit significant, increases in the proportion of CCL2-positive cells with combined Tat and morphine exposure, suggesting that CCL5 preferentially affects CCL2 expression by astroglia. Thus, CCL5 mediates glial activation caused by Tat and morphine, thereby aggravating HIV-1 neuropathogenesis in opiate abusers and non-abusers. CCL5 is implicated as mediating the cytokine-driven amplification of CCL2 production by astrocytes and resultant macrophage/microglial recruitment and activation.

Morphine suppresses intracellular interferon-alpha expression in neuronal cells

Interferon alpha (IFN-alpha) not only plays a key role in innate host immunity against infections but also is involved in the cellular functions of the central nervous system (CNS). In this study, we examined the impact of morphine on IFN-alpha expression in human neuronal cells (NT2-N). Similar to human immune cells, NT2-N cells also expressed IFN-alpha at both mRNA and protein levels. IFN-alpha expression in NT2-N cells, however, was inhibited by morphine. Naltrexone antagonized the inhibitory effect of morphine on IFN-alpha expression in NT2-N cells. The specific mu opioid receptor antagonist, Cys2, Tyr3, Arg5, Pen7-amide (CTAP), also blocked the morphine action on intracellular IFN-alpha expression. Investigation of the mechanisms involved in the morphine action showed that although morphine had little effect on the expression of key IFN regulatory factors (IRFs), morphine inhibited IFN-alpha promoter activation and suppressed the expression and phosphorylation of signal transducer and activator of transcription 1 (STAT1) in the neuronal cells. These findings provide direct in vitro evidence that opioids may impair neuronal cell-mediated innate protection in the CNS.

Electromagnetic millimeter wave induced hypoalgesia: frequency dependence and involvement of endogenous opioids

Millimeter wave treatment (MMWT) is based on the systemic biological effects that develop following local skin exposure to low power electromagnetic waves in the millimeter range. In the present set of experiments, the hypoalgesic effect of this treatment was analyzed in mice. The murine nose area was exposed to MMW of "therapeutic" frequencies: 42.25, 53.57, and 61.22 GHz. MMWT-induced hypoalgesia was shown to be frequency dependent in two experimental models: (1) the cold water tail-flick test (chronic non-neuropathic pain), and (2) the wire surface test (chronic neuropathic pain following unilateral constriction injury to the sciatic nerve). Maximum hypoalgesic effect was obtained when the frequency was 61.22 GHz. Other exposure parameters were: incident power density = 13.3 mW/cm(2), duration of each exposure = 15 min. Involvement of delta and kappa endogenous opioids in the MMWT-induced hypoalgesia was demonstrated using selective blockers of delta- and kappa-opioid receptors and the direct ELISA measurement of endogenous opioids in CNS tissue. Possible mechanisms of the effect and the perspectives of the clinical application of MMWT are discussed.

Serum antioxidant micromineral (Cu, Zn, Fe) status of drug dependent subjects: Influence of illicit drugs and lifestyle

Background

Use of illicit drugs induces multiple nutrient deficiencies. Drug habit, sexual practice and socioeconomic factors influence the nutrient profile of drug dependent subjects. The literature on this issue is still insufficient. This study has tested the hypothesis that illicit drug use and lifestyle impair mineral status. To test this hypothesis, 253 men multiple drug users of age 18–45 years were recruited to investigate their serum copper, zinc and iron levels. Influence of illicit drugs and their lifestyle on the mineral levels was also examined. The study subjects were drug dependent who had shared needles and had sexual activity with multiple partners. Serum concentrations of the minerals were estimated by atomic absorption flame spectrometry.

Results

Results showed a significant increase in serum copper and zinc concentrations, and decrease in iron level in drug dependent subjects. The increase of copper level was found to be much higher than that of zinc. Period of drug abuse had made a significant positive influence on the copper and iron levels, but it was apparently reversed for zinc concentration. Multiple sexual partnerships had significant influence on zinc status. There also were significant relationships observed between body mass index (BMI) as well as certain socioeconomic factors, and mineral status of drug dependent subjects and non-drug dependent controls. A series of multiple linear regression analysis predicted mineral values for education, age and BMI. The group (drug dependent subject = 1, non-drug dependent control = 2) had a significant influence on these parameters. However, after controlling these factors, it was shown that illicit drug use significantly contributed to influence the serum mineral levels.

Conclusion

Illicit drug use impairs serum mineral value causing an increase in copper and zinc and a decrease in iron. Lifestyle and nutritional status of drug dependent subjects influence serum mineral concentrations.

Drugs of abuse, immune modulation, and AIDS

Illicit drugs such as amphetamines, cocaine, marijuana, and opiates alter immune function and decrease host resistance to microbes in vitro and in experimental animal models. Effects on the immune system may be mediated indirectly as a result of drug interactions in the central nervous system (CNS) or directly through activation of cognate receptors on various immune cell types. For marijuana and opioids, seven-transmembranal G protein-coupled receptors have been identified in the CNS and in the immune system that may play a functionally relevant role in immune modulation. There is accumulating evidence that sigma(1) receptors play a comparable role in cocaine-mediated alteration of immune responses. A mode by which these exogenously introduced substances affects immunity and host resistance may be by perturbing the balance of Th(1) proinflammatory versus Th(2) anti-inflammatory cytokines and lipid bioeffectors. However, while illicit drugs have been documented to alter immune functions in vitro and in animal models, there is a paucity of controlled longitudinal epidemiological studies that definitively correlate immunosuppressive effects with increased incidence of infections or immune disorders in humans, including infection with the human immunodeficiency virus (HIV) or disease progression to AIDS.

Opioids and opiates: analgesia with cardiovascular, haemodynamic and immune implications in critical illness

Traumatic injury, surgical interventions and sepsis are amongst some of the clinical conditions that result in marked activation of neuroendocrine and opiate responses aimed at restoring haemodynamic and metabolic homeostasis. The central activation of the neuroendocrine and opiate systems, known collectively as the stress response, is elicited by diverse physical stressor conditions, including ischaemia, glucopenia and inflammation. The role of the hypothalamic-pituitary-adrenal axis and sympathetic nervous system in counterregulation of haemodynamic and metabolic alterations has been studied extensively. However, that of the endogenous opiates/opioid system is still unclear. In addition to activation of the opiate receptor through the endogenous release of opioids, pharmacotherapy with opiate receptor agonists is frequently used for sedation and analgesia of injured, septic and critically ill patients. How this affects the haemodynamic, cardiovascular, metabolic and immune responses is poorly understood. The variety of opiate receptor types, their specificity and ubiquitous location both in the central nervous system and in the periphery adds additional complicating factors to the clear understanding of their contribution to the stress response to the various physical perturbations. This review aims at discussing scientific evidence gathered from preclinical studies on the role of endogenous opioids as well as those administered as pharmacological agents on the host cardiovascular, neuroendocrine, metabolic and immune response mechanisms critical for survival from injury in perspective with clinical observations that provide parallel assessment of relevant outcome measures. When possible, the clinical relevance and corresponding scenarios where this evidence can be integrated into our understanding of the clinical implications of opiate effects will be examined. Overall, the scientific basis to enhance clinical judgment and expectations when using opioid sedation and analgesia in the management of the injured, septic or postsurgical patient will be discussed.

HIV-1 Tat and opiate-induced changes in astrocytes promote chemotaxis of microglia through the expression of MCP-1 and alternative chemokines

Opiates exacerbate human immunodeficiency virus type 1 (HIV-1) Tat(1-72)-induced release of key proinflammatory cytokines by astrocytes, which may accelerate HIV neuropathogenesis in opiate abusers. The release of monocyte chemoattractant protein-1 (MCP-1, also known as CCL2), in particular, is potentiated by opiate-HIV Tat interactions in vitro. Although MCP-1 draws monocytes/macrophages to sites of CNS infection, and activated monocytes/microglia release factors that can damage bystander neurons, the role of MCP-1 in neuro-acquired immunodeficiency syndrome (neuroAIDS) progression in opiate abusers, or nonabusers, is uncertain. Using a chemotaxis assay, N9 microglial cell migration was found to be significantly greater in conditioned medium from mouse striatal astrocytes exposed to morphine and/or Tat(1-72) than in vehicle-, mu-opioid receptor (MOR) antagonist-, or inactive, mutant Tat(delta31-61)-treated controls. Conditioned medium from astrocytes treated with morphine and Tat caused the greatest increase in motility. The response was attenuated using conditioned medium immunoneutralized with MCP-1 antibodies, or medium from MCP-1(-/-) astrocytes. In the presence of morphine (time-release, subcutaneous implant), intrastriatal Tat increased the proportion of neural cells that were astroglia and F4/80+ macrophages at 7 days post-injection. This was not seen after treatment with Tat alone, or with morphine plus inactive Tat(delta31-61) or naltrexone. Glia displayed increased MOR and MCP-1 immunoreactivity after morphine and/or Tat exposure. The findings indicate that MCP-1 underlies most of the response of microglia, suggesting that one way in which opiates exacerbate neuroAIDS is by increasing astroglial-derived proinflammatory chemokines at focal sites of CNS infection and promoting macrophage entry and local microglial activation. Importantly, increased glial expression of MOR can trigger an opiate-driven amplification/positive feedback of MCP-1 production and inflammation.

Drug abuse, innate immunity and hepatitis C virus

Since its discovery in 1989, hepatitis C virus (HCV) has become a major public health problem. HCV chronically infects an estimated 170 million people worldwide. The seroprevalence of anti-HCV antibody in the United States has been estimated at 1.8%, which corresponds to approximately 4 million people. HCV is the most common chronic blood borne infection in the United States, and the leading cause of liver transplantation in developed countries. Injection drug use is the dominant mode of HCV transmission and accounts for up to 90% of current infections. Opiates and other drug abuse, such as alcohol, have been implicated as cofactors in the pathogenesis of HCV disease. Injection drug use has been the most common risk factor identified in alcoholics with HCV infection. Both opiates and alcohol contribute significantly to morbidity and mortality from HCV disease. These drugs most likely act synergistically to promote the development and progression of HCV disease. However, there is limited information available concerning the interaction of the drug abuse with the host cell innate immunity against HCV infection, which is a major barrier to fundamental understanding of the immunopathogenesis of HCV disease. Therefore, defining the role of the drug abuse in the development of chronic HCV infection is of crucial importance and should provide practical guidance toward the reduction of risk factors that interfere with therapeutic approaches for HCV infection and disease. This review paper focuses on the interplay between drug abuse (opiates and alcohol), innate immunity and HCV in the context of the development of HCV disease.

Molecular targets of opiate drug abuse in neuroAIDS

Opiate drug abuse, through selective actions at mu-opioid receptors (MOR), exacerbates the pathogenesis of human immunodeficiency virus-1 (HIV-1) in the CNS by disrupting glial homeostasis, increasing inflammation, and decreasing the threshold for pro-apoptotic events in neurons. Neurons are affected directly and indirectly by opiate-HIV interactions. Although most opiates drugs have some affinity for kappa (KOR) and/or delta (DOR) opioid receptors, their neurotoxic effects are largely mediated through MOR. Besides direct actions on the neurons themselves, opiates directly affect MOR-expressing astrocytes and microglia. Because of their broad-reaching actions in glia, opiate abuse causes widespread metabolic derangement, inflammation, and the disruption of neuron-glial relationships, which likely contribute to neuronal dysfunction, death, and HIV encephalitis. In addition to direct actions on neural cells, opioids modulate inflammation and disrupt normal intercellular interactions among immunocytes (macrophages and lymphocytes), which on balance further promote neuronal dysfunction and death. The neural pathways involved in opiate enhancement of HIV-induced inflammation and cell death, appear to involve MOR activation with downstream effects through PI3-kinase/Akt and/or MAPK signaling, which suggests possible targets for therapeutic intervention in neuroAIDS.

Opioid therapy and immunosuppression: a review

The idea that opioids modulate the immune system is not new. By the late 19th century, Cantacuzene, used morphine to suppress cellular immunity and lower the resistance of guinea pigs to bacterial infection. While exogenous opioids mediate immunosuppression, endogenous opiates exert opposite actions. Acute and chronic opioid administration is known to have inhibitory effects on humoral and cellular immune responses including antibody production, natural killer cell activity, cytokine expression, and phagocytic activity. Opiates behave like cytokines, modulating the immune response by interaction with their receptors in the central nervous system and in the periphery. Potential mechanisms by which central opiates modulate peripheral immune functions may involve both the hypothalamic-pituitary-adrenal axis and the autonomic nervous system. The presence of opioid receptors outside the central nervous system is increasingly recognized. Those receptors have been identified not only in peripheral nerves but also in immune inflammatory cells. The immunosuppression mediated by opiates may explain the increased incidence of infection in heroin addicts. Opiates may also promote immunodeficiency virus infection by decreasing the secretion of alpha and beta chemokines (important inhibitory cytokines for the expression of HIV) and at the same time increasing the expression of chemoreceptors CCR5 and CCR3, coreceptors for the virus. The fact that peripheral immunosupression is mediated at least in part by opioid receptors located in the central nervous system and that intrathecally administered opioids do not exert the same immunosuppressive effects may have important clinical implications for those patients receiving long-term opioid therapy for malignant and nonmalignant pain.

Millimeter wave-induced suppression of B16 F10 melanoma growth in mice: involvement of endogenous opioids

Millimeter wave treatment (MMWT) is widely used in Eastern European countries, but is virtually unknown in Western medicine. Among reported MMWT effects is suppression of tumor growth. The main aim of the present "blind" and dosimetrically controlled experiments was to evaluate quantitatively the ability of MMWT to influence tumor growth and to assess whether endogenous opioids are involved. The murine experimental model of B16 F10 melanoma subcutaneous growth was used. MMWT characteristics were: frequency, 61.22 GHz; average incident power density, 13.3 x 10(-3) W/cm2; single exposure duration, 15 min; and exposure area, nose. Naloxone (1 mg/kg, intraperitoneally, 30 min prior to MMWT) was used as a nonspecific blocker of opioid receptors. Five daily MMW exposures, if applied starting at the fifth day following B16 melanoma cell injection, suppressed subcutaneous tumor growth. Pretreatment with naloxone completely abolished the MMWT-induced suppression of melanoma growth. The same course of 5 MMW treatments, if started on day 1 or day 10 following tumor inoculations, was ineffective. We concluded that MMWT has an anticancer therapeutic potential and that endogenous opioids are involved in MMWT-induced suppression of melanoma growth in mice. However, appropriate indications and contraindications have to be developed experimentally before recommending MMWT for clinical usage.

Preferential vulnerability of astroglia and glial precursors to combined opioid and HIV-1 Tat exposure in vitro

Human immunodeficiency virus (HIV)-1 infection can cause characteristic neural defects such as progressive motor dysfunction, striatal pathology and gliosis. Recent evidence suggests that HIV-induced pathogenesis is exacerbated by heroin abuse and that the synergistic neurotoxicity is a direct effect of heroin on the CNS, an alarming observation considering the high incidence of HIV infection with injection drug abuse. Although HIV infection results in neurodegeneration, neurons themselves are not directly infected. Instead, HIV affects microglia and astroglia, which subsequently contributes to the neurodegenerative changes. Opioid receptors are widely expressed by macroglia and macroglial precursors, and the activation of mu-opioid receptors can modulate programmed cell death, as well as the response of neural cells to cytotoxic insults. For this reason, we questioned whether opioid drugs might modify the vulnerability of macroglia and macroglial precursors to HIV-1 Tat protein. To address this problem, the effects of morphine and/or HIV Tat(1-72) on the viability of macroglia and macroglial precursors were assessed in mixed-glial cultures derived from mouse striatum. Our findings indicate that sustained exposure to morphine and Tat(1-72) viral protein induces the preferential death of glial precursors and some astrocytes. Moreover, the increased cell death is mediated by mu-opioid receptors and accompanied by the activation of caspase-3. Our results imply that opiates can enhance the cytotoxicity of HIV-1 Tat through direct actions on glial precursors and/or astroglia, suggesting novel cellular targets for HIV-opiate interactions.

A non-peptide substance P antagonist (CP-96,345) inhibits morphine-induced NF-kappa B promoter activation in human NT2-N neurons

Opioids and the neuropeptide substance P (SP) modulate the expression of inflammatory cytokines and chemokines, which are under the control of nuclear factor kappaB (NF-kappaB). We investigated whether the neurokinin-1 receptor (SP receptor) pathway is biologically involved in morphine-mediated modulation of NF-kappaB promoter activation in a human neuronal cell line (NT2-N) that expresses both the mu-opioid receptor (MOR) and the SP receptor. Morphine significantly enhanced NF-kappaB promoter-directed luciferase activity in NT2-N neurons. DAMGO, a selective mu-opioid receptor agonist, also induced NF-kappaB promoter activation. The induced activation of NF-kappaB promoter by morphine or DAMGO was abolished not only by naltrexone (a opioid receptor antagonist) and CTAP (a selective, competitive mu-opioid receptor antagonist), but also by CP-96,345, a non-peptide SP receptor antagonist. Investigation of the mechanism responsible for morphine-induced activation of NF-kappaB promoter in NT2-N neurons demonstrated that morphine activates the SP promoter and induces SP expression in these cells. We also observed that SP activated NF-kappaB promoter and that CP-96,345 downregulated the expression of endogenous SP. Furthermore, dual immunofluorescent labeling revealed that there is co-expression of NK-1R and MOR in the processes of NT-2N neurons. These results suggest that morphine, by activating MOR, engages a positive feedback loop between NK-1R and SP. Activation of NK-1R could then impact NF-kappaB expression and therefore may be an important participant in the effect of morphine on immune responses in the central nervous system.

Serum immunoglobulins and white blood cells status of drug addicts: influence of illicit drugs and sex habit

The aim of this study was to investigate the serum immunoglobulins and white blood cells status of drug addicts and to assess the extent of influence of drug habit and sexual practice on the immune components. The study was conducted among 253 male drug addicts and 100 non-addict controls of aged 18-45 years. An enzyme-linked immunosorbent assay (ELISA) was employed to analyse the serum immunoglobulin concentrations. White blood cells profile was estimated by counting 200 cells. Results showed a significant increase (p<0.03) of serum IgG, IgA and IgM in the drug addicts (6.93+/-1.53 g/l, 2.90+/-1.13 g/l and 1.72+/-0.73 g/l, respectively) compared to those in the cohort controls (6.52+/-1.05 g/l, 2.61+/-0.83 g/l and 1.52+/-0.59 g/l, respectively). A significant (p=0.00) decrease of peripheral lymphocytes (51.8+/-15.2 vs. 71.9+/-11.5) was noted in the drug addicts. Monocytes (8.3+/-4.9), neutrophils (128.2+/-18.9) and eosinophils (11.4+/-5.8) were found to be increased in the drug addicts against those in the controls (5.2+/-2.5, 113.2+/-13.0 and 9.6+/-5.8, respectively). Multiple drug abuse for longer period had resulted in a significant (p<0.05) decrease of serum immunoglobulins and lymphocytes. The longer period of addiction had also made a significant (p<0.05) decrease of eosinophils (p=0.05) and an increase of monocytes and neutrophils. Sex with multiple sexual partners had shown a significant (p<0.01) decrease of serum immunoglobulins and eosinophils.

Soluble proteolytic enzyme release by naive and HIV-infected cultured T-cells

The possible hydrolysis of leucine enkephalin was measured in the presence of cell-free supernatants obtained from naive and chronically HIV-infected immunocompetent cell lines. The data obtained indicate that, under all conditions examined, leu-enkephalin was partially degraded; its disappearance was associated with the appearance of peptides whose composition is consistent with the involvement of three enzyme classes, i.e. aminopeptidases, dipeptidylaminopeptidases and dipeptidylcarboxypeptidases. In the presence of supernatants obtained from infected cells, substrate hydrolysis was less than that measured in naive controls. This appears to result from infection-associated variations in the activity of all three enzyme classes active on the substrate, variations that were different for each class. Specifically, in unfractionated supernatants, the activity of aminopeptidases was reduced, that of dipeptidylaminopeptidase was increased, and the activity of dipeptidylcarboxypeptidases was nearly unmodified. Data obtained upon chromatographic separation of the soluble supernatants allowed for the identification of features that can be interpreted as indicating the existence of infection-associated variations in the activity of single enzymes. The sum of the data shown makes it possible to advance the hypothesis that the infection-associated modifications in the release of proteolytic enzymes may contribute to the alterations in the functionality of immunocompetent cells induced by viral infection.

The promotion of tumor metastasis by surgery and stress: immunological basis and implications for psychoneuroimmunology

This mini-review emphasizes a psychoneuroimmunology (PNI) perspective of the hypothesis that stress and surgical excision of the primary tumor can promote tumor metastasis. It first establishes the empirical and theoretical basis for control of metastasis by cell-mediated immunity (CMI), as well as the interactive role of non-immunological risk factors. It then describes the various aspects of surgery that suppress CMI, and the neuroendocrine mechanisms mediating suppression by stress and surgery. Last, it briefly reviews the empirical evidence, from animal and human studies, for the promotion of metastasis by stress and surgery, with specific reference to the mediating role of CMI. It is concluded that: (a) Immunological mechanisms most likely play a role in limiting metastasis in patients with solid tumors. (b) Immunosuppression can be deleterious, especially when surgery is conducted early, before the tumor develops insurmountable mechanisms to escape immune destruction. (c) The most sensitive period for the establishment of metastases is the immediate aftermath of surgery. Interventions aiming at reducing stress and immunosuppression should thus strive to start beforehand. (d) 'Psychological and physiological insults activate similar neuroendocrine mechanisms of immunosuppression. Therefore, a multimodal therapeutic approach should be used to prevent tumor metastasis during the perioperative period. (e) Studies employing interventions aimed at reducing the surgical stress response should preferably assess immunological indices with an established clinical relevance, and follow up long-term recurrence provided sample size assure statistical power. (f) The progress toward earlier detection of cancer, and our growing understanding of immunosuppression, continuously improves the chances for successful PNI interventions.

Nutritional status of drug addicts undergoing detoxification: prevalence of malnutrition and influence of illicit drugs and lifestyle

The aim of the present study was to investigate the nutritional status of drug addicts, the prevalence of malnutrition among them and the influence of their drug habit and lifestyle factors on their nutritional indices. The study was conducted among 253 male drug addicts, who sought detoxification at the Central Drug Addiction Treatment Hospital, Dhaka, during the period of June 1998-July 1999. One hundred age-, height- and socioeconomic-matched non-addicted healthy men were recruited by convenience as cohort controls. Results showed that the drug addicts had significantly (P<0.001) lowered BMI, haemoglobin, and serum total protein and albumin levels. Clinical signs of nutrient deficiency were diagnosed in about 74 % of drug addicts. The BMI, biochemical values and nutrient deficiency signs indicated that more than 60 % of drug addicts were suffering from multiple malnutrition. One-way ANOVA demonstrated a significant (P<0.05) negative correlation between drug habit, sexually transmitted diseases and selected nutritional indices, and a positive correlation between education, income and the nutritional indices. A series of multiple regression analyses revealed that education, income and age showed significantly predicted BMI and biochemical indices, and the group (non-drug addicts or drug addicts) had a significant negative effect on these parameters in favour of controls.

Injection drug use facilitates hepatitis C virus infection of peripheral blood mononuclear cells

Infection of peripheral blood mononuclear cells (PBMCs) with hepatitis C virus (HCV) has been demonstrated and has been found to play a role in relapse of HCV disease and vertical transmission of HCV. Injection drug use is thought to impair function of the immune system and induce tolerance to viruses; therefore, HCV infection of PBMCs could be more likely to occur in injection drug users (IDUs) with HCV infection. Of 108 women who tested negative for human immunodeficiency virus type 1 and positive for HCV RNA, 51 had a history of injection drug use and 57 had no known risk factor for HCV infection. HCV infection was found, by nested reverse-transcription polymerase chain reaction analysis, in the PBMCs of 33 IDUs and of 13 non-IDUs (P=.00003). No correlation was found between infection of the PBMCs and HCV genotype or virus load. Route of transmission and viral factors, as well as immunologic dysfunction, may play a role in viral tropism.

Serum vitamin E, C and A status of the drug addicts undergoing detoxification: influence of drug habit, sexual practice and lifestyle factors

BACKGROUND

The study was carried out on the hypothesis that drug addicts would have reduced vitamin E, C and A status which could be influenced by drug habit, sexual practice and lifestyle factors.

METHOD

Serum concentrations of Vitamin E, C and A of male drug addicts and cohort controls were analysed, and influence of drug habit, sexual practice and lifestyle factors of the addicts on the vitamin status was assessed. The study was conducted among 253 drug addicts who sought detoxification voluntarily during the period of June 1997 to July 1998 at the Central Drug Addiction Treatment Hospital, Dhaka, and 100 cohort control men. Research instruments were questionnaire and blood specimens. HPLC and spectrophotometric methods were used to determine the vitamin levels in sera of drug addicts.

RESULTS

alpha-Tocopherol (12.60+/-3.73 compared with 16.3+/-3.37 micromol/l; t=8.6, P=0.05), ascorbic acid (21.59+/-10.5 compared with 38.3+/-13.62 micromol/l; t=10.93, P=0.003) and retinol (1.15+/-0.39 compared with 1.33+/-0.30 micromol/l; t=5.28, P=0.048) in the drug addicts were significantly low as compared to those in the cohort controls. Use of multiple illicit drugs for a longer period of time did result in reduced levels of these vitamins. A significant reduction in retinol concentration was noted among the multiple drug users (F(2,250)=3.23, P=0.041). Duration of addiction had a significant linear correlation with the level of reduction in retinol (F(2,250)=3.23, P=0.041) and alpha-tocopherol (F(2,250)=3.06, P=0.049). Apart from having a significant negative correlation between number of sexual partners and retinol level (F(3,247)=2.65, P=0.049), sexual practice did not have any influence on the vitamin status of the addicts. Occupation did have a significant effect on the ascorbic acid level (F(4,248)=2.46, P=0.046), but other socioeconomic factors like income, age etc did not influence the vitamin E, C and A levels. Body mass index had a positive linear correlation with the vitamins, but it was significant only with vitamin C (F(2,250)=7.06, P=0.001).

CONCLUSIONS

These results could have important implications for providing an antioxidant therapy to drug addicts and thus rehabilitating them into normal life. Risk of HIV infection and transmission (if any) could be reduced or inhibited.

Neuropeptide degradation in naive and steroid-treated allergic saliva

The hydrolysis of neuropeptides and possible variations in hydrolysis following steroidal treatment, were examined in the presence of saliva collected from allergic volunteers; data obtained were compared to those obtained with a age and sex-matching group of healthy controls. The results reported indicate the presence of a statistically significant increase in the hydrolysis of the model substrate in allergic as compared to control saliva, and a reduction of substrate hydrolysis in treated as compared to naive allergic saliva. Total enzyme activity, the relative activity of the three classes of substrate-active enzymes (aminopeptidases, dipeptidylaminopeptidases, and dipeptidylcarboxypeptidases), the allergy-associated variations of these activities, and the variations associated to therapy were found to be different in male and female saliva. Specifically, in the controls, the lower level of hydrolysis evident in female as compared to male saliva appeared to be principally induced by lower activity of aminopeptidases. Under allergic conditions, a sex-different increase in the activity of all three classes of substrate-active enzymes modified the hydrolysis pattern differently in samples obtained from male and female donors. Finally, pharmacological treatment induced opposite effects on the enzymes present in each sex: in male saliva, the activity of all three classes of substrate-active enzymes--and, thus, of substrate hydrolysis--was reduced near to the levels measured in the controls. In female saliva, the reduction in the activity of aminopeptidases was coupled with an increase in the activity of dipeptidylaminopeptidases, causing substrate hydrolysis to remain near the levels measured in naive allergic, rather than control, saliva.

U50488 inhibits HIV-1 expression in acutely infected monocyte-derived macrophages

Opioids may play an immunomodulatory role in the pathogenesis of human immunodeficiency virus-1 (HIV-1) infection. Recently, synthetic kappa-opioid receptor (KOR) ligands have been found to have anti-human immunodeficiency virus type 1 activity in acutely infected brain macrophages. In the present study, we investigated whether the selective KOR ligand U50488 would exert such an anti-HIV-1 effect in acutely infected blood monocyte-derived macrophages (MDM). Treatment of acutely infected MDM with U50488 induced a concentration-dependent inhibition of HIV-1 expression. The dose--response relationship of U50488 was U-shaped with a peak effect observed at 10(-13) M, which was evident at both 7 and 14 days post-infection. The KOR antagonist nor-binaltorphimine blocked the anti-HIV-1 effect of U50488 by 73%, indicating involvement of a KOR-mediated mechanism. Also, expression of KOR mRNA and binding activity with a fluorescence-labeled KOR ligand supported the existence of KOR on MDM. Antibodies to the beta-chemokine, RANTES (regulated on activation normal T-cell expressed and secreted), but not to various other cytokines, blocked U50488 inhibition by 56% suggesting that the anti-HIV-1 effect of U50488 involved, in part, the production of RANTES by MDM. Taken together, these in vitro findings support the anti-HIV-1 property of U50488, and suggest that KOR ligands may have therapeutic potential for treating patients with acquired immunodeficiency syndrome.

Morphine suppresses complement receptor expression, phagocytosis, and respiratory burst in neutrophils by a nitric oxide and mu(3) opiate receptor-dependent mechanism

We investigated whether morphine and fentanyl influence surface receptor expression, phagocytic activity and superoxide anion generation of neutrophils in a whole blood flow cytometric assay. Morphine suppressed complement and Fcgamma receptor expression and neutrophil function in a concentration- and time-dependent manner. Morphine-induced changes were similar to those caused by the nitric oxide (NO) donor S-nitroso-N-acetyl-penicillamine and were abolished by preincubation with the NO synthase inhibitor N-nitro-L-arginine as well as naloxone. Fentanyl had no immunosuppressive effects. These results suggest that these neutrophil functions are inhibited by morphine-stimulated NO release mediated by the mu(3) opiate receptor subtype found on immunocytes.

Morphine Up-regulates expression of substance P and its receptor in human blood mononuclear phagocytes and lymphocytes

In vitro and in vivo studies have indicated that there is an important relationship between morphine and neuropeptide substance P (SP). We therefore investigated the interaction of morphine and cultured human immune cells on the expression of SP, a neuropeptide which we have recently demonstrated to be produced by human monocytes and lymphocytes. Morphine up-regulated SP production in human mononuclear phagocytes and lymphocytes at both the mRNA and the protein level. In addition, morphine induced SP receptor (NK-1R) expression in human lymphocytes. The specific morphine receptor antagonist (naltrexone) blocked morphine-induced SP expression in human mononuclear phagocytes, supporting the concept of authentic morphine receptor-mediated regulation. Since SP modulates neurogenic inflammation and immunologic events, these data suggest that morphine-induced SP expression in cells of the immune system may be of importance in the pathogenesis of immune-mediated diseases, including neuroimmunologic diseases and AIDS.

Spectroscopic evidence of beta-turn in N-glycated peptidomimetics related to leucine-enkephalin

The conformational differences caused by N-glycation of the amide bond in endogenous opioid pentapeptide leucine-enkephalin (Tyr-Gly-Gly-Phe-Leu) have been explored in solution using FTIR spectroscopy, NMR and molecular modelling. The compounds studied include protected and unprotected enkephalin analogues N-alkylated at the second (Gly2) amino acid residue with a 6-deoxy-D-galactose moiety (1-3). Comparison of the amide I component bands in the FTIR spectra, measured in trifluoroethanol (TFE), CHCl3 and DMSO, revealed significant differences in the intensity as well as shifts in component band frequencies for glycopeptides 1-3. We found that only the FTIR spectrum of the fully protected compound 1 indicated the presence of a higher population of beta-turns, while the spectra of the partially protected and unprotected glycopeptides 2 and 3 reflected the dominance of unordered or open structures, with some low population of turns. The observed NOE connectivities in CDCl3 for both isomers of the fully protected compound 1, the all-trans one and another with Tyr1-Gly2 peptide bond in cis conformation, indicate the presence of a beta-like turn conformation. Molecular dynamics simulations of the glycopeptide 1 obtained by unconstrained energy minimization of trans- and cis-1 shows that one of trans form conformations is consistent with beta-turn whereas cis isomer has revealed less-compact turn.

Detection of neuropeptides using on-capillary copper complexation and capillary electrophoresis with electrochemical detection

Capillary electrophoresis with electrochemical detection using a carbon fiber electrode in conjunction with on-capillary copper complexation was evaluated for the determination of peptides in standard and biological matrices. Peptides composed of 2-10 amino acids were investigated. A comparison was made between the responses obtained for peptides containing the oxidizable residue tyrosine and those obtained for their respective copper complexes. Electrochemical detection of non-tyrosine-containing peptides and a cyclic peptide was also demonstrated. A separation of leucine (Leu)-enkephalin and five metabolites was developed and then used for the investigation of Leu-enkephalin metabolism in plasma. The appearance of the des-tyrosine (des-Tyr) Leu-enkephalin, which cannot be detected directly at a carbon electrode, was monitored using the on-capillary complexation technique. Direct injection of the plasma sample was possible using this methodology.

Cytokine pattern secretion by murine spleen cells after inactivated Candida albicans immunization. Effect of cocaine and morphine treatment

In the present work we have analyzed: i) the effect of heat-inactivated Candida albicans immunization on the cytokine production by murine spleen cells; ii) the effect of a subchronic cocaine and morphine treatment on this production. The treatment with a single dose of inactivated Candida blastospores induced interleukin-2(IL-2), interferon-gamma (IFNgamma) and interleukin-4 (IL-4) production at 24 h after in vitro restimulation of splenocytes. In this model, the exposure to morphine (25 mg/kg, 5 days before, during and 5 days after inoculation with the yeast) significant decreased IL-2 and IL-4 levels, while secretion of IFN-gamma was unaltered. The same cocaine treatment (10 mg/kg) resulted in unchanged levels of the three cytokines tested. The results showed that non-viable Candida cells of this strain induce a predominant Th0 response. This immune effect is in part impaired only by a subchronic administration of morphine.

Cocaine potentiates the switch between latency and replication of Epstein-Barr virus in Raji cells

This paper shows that cocaine amplifies Epstein-Barr virus (EBV) reactivation in Raji cells. Its effect on early viral protein synthesis was maximal when it was added with 12-O-tetradecanoyl phorbol-13-acetate (TPA) plus n-butyrate, but nil when added alone. The enhancing effect of cocaine on early replicative stages of latent EBV was associated with an increase of Ca(2+) mobilization induced by the drug and with an induction of cellular protein phosphorylation in chemicals and cocaine-treated Raji cells. Cocaine also acted synergistically with TPA and n-butyrate to induce Z Epstein-Barr replication activator (ZEBRA), a nuclear phosphoprotein responsible for the activation of early viral gene expression. These findings provide the first evidence that cocaine may represent an important co-factor in the reactivation of early stages of latent EBV infection.

Delta-opioid receptor antagonist inhibits immunomodulation by Met-enkephalin analogs

The methionine-enkephalin (Met-enkephalin, Tyr-Gly- Gly-Phe-Met) analogs Tyr-D-Ala-Gly-MePhe-Met NHC(3)H(7)-iso (1) and Tyr-D-Ala-Gly-MePhe-Gly-NHC(3)H(7)-iso (2) have been shown to enhance human T cell proliferation in in vitro treatment. Their immunomodulatory activities were completely blocked by naloxone, an opioid antagonist. Now we demonstrate that a selective delta-opioid receptor antagonist, ICI-174,864, completely blocks enhancement of T cell proliferation by analogs (1) and (2). The T cell-stimulatory effect was only partially inhibited by the mu-receptor-selective antagonist, beta-funaltrexamine hydrochloride. The kappa-opioid receptor antagonist, nor-binaltorphimine dihydrochloride, showed no effect on T cell-proliferation stimulated by analogs (1) and (2). These observations suggest that analogs (1) and (2) of Met-enkephalin stimulate T cell proliferation predominantly via delta-opioid receptor present on T cells.

Relationship between HIV-1 viral load and continued drug use in untreated infected injection drug users

The role of continued drug use in development of AIDS has been investigated, using mainly CD4(+) cells as outcome variable. The objective of this study was to verify whether continued drug use can influence HIV-1 plasma viral load.We used cross-sectional enrolment data of the HIV-infected IDUs cohort study Manif 2000 (October 1995-October 1996), recruiting patients in hospital departments of Marseilles, Nice and Paris suburbs. To minimize biases due to differential access to health care, only patients receiving outpatient care for at least 2 years but with no antiretroviral treatment were selected for analysis (n = 108). Available information regarding clinical and laboratory information from medical records and clinical examination as well as drug use and HIV-related risk practices were obtained by a face-to-face and a self-administered questionnaire. Patients denying recent heroin injection were cross-validated by a serological assay to detect morphine. Forty-two patients (39%) reported recent heroin injection; among those denying recent use (n=66), eight (positive for serum morphine assay) were re-classified as IDUs. A difference of 0.35 log in viral load was observed between active and ex-IDUs which increases (0.6 log, p=0.03) in those who have been using drugs for 10 years or more.This result persisted when adjusted for CD4(+) counts, clinical stage or years since diagnosis. Continued drug use may have a significant but limited impact on HIV viral load only in patients with a longer history of drug use. Consequences of persisting drug use on long-term progression to AIDS has to be investigated further.

Morphine reduces mortality in mice following ocular infection with HSV-1

To determine the effect of chronic opioid treatment on mice infected with herpes simplex virus (HSV-1), female ICR mice were administered saline or morphine (25 mg/kg) subcutaneously (s.c.) 3 X /day and infected five days later via corneal scarification and inoculation with 150-210 plaque forming units of HSV-1. Mice deprived of morphine succumbed following infection faster than morphine- or saline-maintained mice, and morphine-maintained mice had a higher cumulative survival than either saline-maintained or morphine-deprived mice. There was no significant difference in cytokine mRNA or protein levels by RT-PCR and ELISA, respectively, in the eyes, trigeminal ganglia, cerebellum, or brain stem, comparing morphine-maintained to saline-treated mice. Similarly, there were no differences in the viral load in the eyes and trigeminal ganglia during the acute infection comparing these two groups assayed three and six days post-infection. While there were no differences in the expression of viral transcripts in the eyes and trigeminal ganglia during the acute infection, HSV-1 infected cell polypeptide 27 expression was reduced in the brain stem of morphine-maintained mice. Collectively, the results suggest that mice maintained on morphine antagonize the spread of HSV-1 in the central nervous system and thus, reduce the incidence of viral-induced encephalitis.

Increased replication of Sendai virus in morphine-treated epithelial cells: evidence for the involvement of the intracellular levels of glutathione

This paper shows that morphine increases Sendai virus replication in cultured epithelial cells. The effect was maximal when it was added before viral infection. Morphine also reduced the intracellular level of glutathione, namely, the oxidative and most abundant cell thiol. Altered intracellular redox status has recently been proposed as a factor influencing viral infection. Support for this view was provided by our data showing that inhibition of de novo glutathione synthesis, using L-buthionine sulfoximine, increased virus replication. These findings provide the first evidence that morphine increases the susceptibility to virus infection by altering the intracellular levels of glutathione.

Hydrolysis of peripheral leucine enkephalin in allergic asthma

Plasma hydrolysis of leucine enkephalin was studied in a group of patients affected by seasonal allergic asthma in acute and quiescent stage; data were compared with those obtained from a control group of healthy volunteers. Results obtained indicate a statistically significant reduction of leu-enkephalin hydrolysis in allergic subjects. In the quiescent stage, substrate degradation is reduced, and the pattern of the hydrolysis by-products is modified with respect to normal controls. In the acute stage, hydrolysis is further reduced, and the pattern of the hydrolysis by-products is further modified with respect to the quiescent stage. The variations of leu-enkephalin hydrolysis appear to be controlled by decreased activity of proteolytic enzymes and by increased activity of the low-molecular-weight plasma inhibitors active on these enzymes. The sum of these processes is conducive to a distribution of enkephalin-hydrolyzing enzymes, as well as a hydrolysis pattern, that appears to be specific for the allergic subjects and distinct from that seen in the controls.

Differential effects of acute morphine administrations on polymorphonuclear cell metabolism in various mouse strains

This paper shows that an acute morphine treatment dose-dependently alters the energetic and oxidative metabolism of polymorphonuclear leukocytes obtained from BALB/c and DBA/2 mice, while phagocytic cells from C57BL/6 were not affected. In sensitive mouse strains, i.e. BALB/c and DBA/2, morphine decreased both ATP concentration and energy charge potential. At the same time, ATP catabolic products, i.e. nucleosides (inosine+adenosine) and oxypurines (hypoxanthine+xanthine+uric acid), significantly increased, indicating an imbalance between energy production and consumption. Morphine treatment also induced malondialdehyde and superoxide anions production in leukocyte cells from sensitive mice. The opiate antagonist naloxone blocked morphine-induced modifications by the lower morphine dose. The same parameters in cells from C57BL/6 mice were not affected. These findings confirm that: i) the phagocytic cells are an important target for the in vivo effects of morphine, and ii) the genotype-dependent variation influences the immunological responsiveness to opiates.

Kappa-opioid potentiation of tumor necrosis factor-alpha-induced anti-HIV-1 activity in acutely infected human brain cell cultures

Opioids have been postulated to play an immunomodulatory role in the pathogenesis of HIV-1. Synthetic kappa-opioid receptor (KOR) ligands have been found to inhibit HIV-1 expression in acutely infected microglial cell cultures. We recently found that interleukin(IL)-1beta and tumor necrosis factor(TNF)-alpha have antiviral effects in acutely infected mixed glial/neuronal cell cultures. In the present study, we investigated whether selective KOR ligands would exert antiviral effects in acutely infected brain cell cultures. While the KOR ligand trans-3,4-dichloro-N-methyl-N[2-(1-pyrolidinyl)cyclohexyl]benze neaceamide methanesulfonate (U50,488) alone had little anti-HIV-1 activity, this opioid potentiated in a concentration-dependent manner the antiviral activity of TNF-alpha, but not of IL-1beta. The potentiating effect of U50,488 was detected after a 6-hr pretreatment and peaked at 24 hr. The KOR antagonist nor-binaltorphimine completely blocked the potentiating effect of U50,488, suggesting the involvement of a KOR-mediated mechanism. Antibodies to TNF-alpha completely blocked the potentiating effect of U50,488, suggesting a critical role for TNF-alpha. Antibodies to IL-1beta blocked the potentiating effect of U50,488, suggesting that IL-1beta was released following U50,488 treatment, which might contribute to the potentiating effect of U50,488. These in vitro findings support the notion that synthetic kappa-opioids could be considered as potential adjunctive therapeutic agents in HIV-1-related brain disease.