Opioid therapy and immunosuppression: a review

Substance use disorders: psychoneuroimmunological mechanisms and new targets for therapy

An estimated 76.4 million people worldwide meet criteria for alcohol use disorders, and 15.3 million meet criteria for drug use disorders. Given the high rates of addiction and the associated health, economic, and social costs, it is essential to develop a thorough understanding of the impact of substance abuse on mental and physical health outcomes and to identify new treatment approaches for substance use disorders (SUDs). Psychoneuroimmunology is a rapidly expanding, multidisciplinary area of research that may be of particular importance to addiction medicine, as its focus is on the dynamic and complex interactions among behavioral factors, the central nervous system, and the endocrine and immune systems (Ader, 2001). This review, therefore, focuses on: 1) the psychoneuroimmunologic effects of SUDs by substance type and use pattern, and 2) the current and future treatment strategies, including barriers that can impede successful recovery outcomes. Evidence-based psychosocial and pharmacotherapeutic treatments are reviewed. Psychological factors and central nervous system correlates that impact treatment adherence and response are discussed. Several novel therapeutic approaches that are currently under investigation are introduced; translational data from animal and human studies is presented, highlighting immunotherapy as a promising new direction for addiction medicine.

Surgery and stress promote cancer metastasis: new outlooks on perioperative mediating mechanisms and immune involvement

Surgery for the removal of a primary tumor presents an opportunity to eradicate cancer or arrest its progression, but is also believed to promote the outbreak of pre-existing micrometastases and the initiation of new metastases. These deleterious effects of surgery are mediated through various mechanisms, including psychological and physiological neuroendocrine and paracrine stress responses elicited by surgery. In this review we (i) describe the many risk factors that arise during the perioperative period, acting synergistically to make this short timeframe critical for determining long-term cancer recurrence, (ii) present newly identified potent immunocyte populations that can destroy autologous tumor cells that were traditionally considered immune-resistant, thus invigorating the notion of immune-surveillance against cancer metastasis, (iii) describe in vivo evidence in cancer patients that support a role for anti-cancer immunity, (iv) indicate neuroendocrine and paracrine mediating mechanisms of stress- and surgery-induced promotion of cancer progression, focusing on the prominent role of catecholamines and prostaglandins through their impact on anti-cancer immunity, and through direct effects on the malignant tissue and its surrounding, (v) discuss the impact of different anesthetic approaches and other intra-operative procedures on immunity and cancer progression, and (vi) suggest prophylactic measures against the immunosuppressive and cancer promoting effects of surgery.

MicroRNAs in opioid pharmacology

MicroRNAs (miRNA), a class of ~22-nucleotide RNA molecules, are important gene regulators that bind to the target sites of mRNAs to inhibit the gene expressions either through translational inhibition or mRNA destabilization. There are growing evidences that miRNAs have played several regulatory roles in opioid pharmacology. Like other research fields such as cancer biology, the area where numerous miRNAs are found to be involved in gene regulation, we assume that in opioid studies including research fields of drug additions and opioid receptor regulation, there may be more miRNAs waiting to be discovered. This review will summarize our current knowledge of miRNA functions on opioids biology and briefly describe future research directions of miRNAs related to opioids.

Methadone diminishes neuroinflammation and disease severity in EAE through modulating T cell function

Methadone is known to exert modulatory effects on the immune system. We investigated the potential effects of methadone on infiltration of inflammatory cells into the spinal cord, as well as the proliferative and cytokine responses of T cells in MOG(35-55)-induced experimental autoimmune encephalomyelitis in mice. Methadone significantly suppressed clinical signs of the disease and level of inflammatory cytokines (p<0.05) produced by T cells. Moreover, invasion of inflammatory cells into the spinal cord was significantly decreased by methadone (p<0.05). Our data point to therapeutic effects of methadone and highlight the beneficial role of opioid receptor signaling in the context of autoimmune neuroinflammation.

Ceasing intrathecal therapy in chronic non-cancer pain: an invitation to shift from biomedical focus to active management

Objective

To report long term experience (1997–2009) of intrathecal (IT) therapy for chronic non-cancer pain in the context of our team’s increasing emphasis on active management.

Design

Descriptive case series.

Setting

Australian tertiary multidisciplinary pain center, Hunter Integrated Pain Service (HIPS).

Intervention

This case series reports the changing use of IT implanted drug delivery systems (IDDSs) for chronic non-cancer pain over 13 years. Initially IT therapy was used selectively following multidisciplinary assessment and double blind IT trial. Typical therapy combined opioid with clonidine. Multidimensional management was offered. Treatment strategy changed in 2003 due to HIPS experience of limited therapeutic gains and equivocal support for IT therapy in the literature. Subsequently IT therapy was no longer initiated for non-cancer pain and those on established regimes were encouraged to shift to oral/transdermal opioids with greater emphasis on active management. Patient education and consultation were key elements. Where IT cessation was elective gradual dose reduction commenced as an outpatient. In elective and urgent cases ketamine infusion and oral clonidine were used during hospital admissions to cover the switch to oral/transdermal opioids. Over the study period transition occurred to a broader management framework in which IT therapy for chronic non-cancer pain was no longer supported by HIPS.

Results

25 patients were managed using IDDSs; 8 implanted by HIPS and 17 by other teams. Dose escalation and adverse effects were common. 24 of 25 patients ceased IT therapy; 7 (29%) with urgent IDDS related complications, 16 (67%) electively and 1 due to an unrelated death. The remaining patient returned to her original team to continue IT therapy. One post-explantation patient transferred to another team to recommence IT therapy. The remainder were successfully maintained on oral/transdermal opioids combined with active management.

OPRM1 and diagnosis-related posttraumatic stress disorder in binge-drinking patients living with HIV

Posttraumatic stress disorder (PTSD) has been linked to numerous negative outcomes in persons living with HIV (PLH) and there is evidence that PTSD symptoms may play a role in maintaining alcohol use problems. The opioid receptor mu-1 (OPRM1) gene may play a role in both PTSD and alcohol use. We examined the association between PTSD and drinking motives as well as variation in the OPRM1 as a predictor of both PTSD and drinking motives in a sample of 201 PLH reporting recent binge drinking. Self-reported PTSD symptom severity was significantly associated with drinking motives for coping, enhancement, and socialization. OPRM1 variation was associated with decreased PTSD symptom severity as well as enhancement motives for drinking.

Current research on opioid receptor function

The use of opioid analgesics has a long history in clinical settings, although the comprehensive action of opioid receptors is still less understood. Nonetheless, recent studies have generated fresh insights into opioid receptor-mediated functions and their underlying mechanisms. Three major opioid receptors (μ-opioid receptor, MOR; δ-opioid receptor, DOR; and κ-opioid receptor, KOR) have been cloned in many species. Each opioid receptor is functionally sub-classified into several pharmacological subtypes, although, specific gene corresponding each of these receptor subtypes is still unidentified as only a single gene has been isolated for each opioid receptor. In addition to pain modulation and addiction, opioid receptors are widely involved in various physiological and pathophysiological activities, including the regulation of membrane ionic homeostasis, cell proliferation, emotional response, epileptic seizures, immune function, feeding, obesity, respiratory and cardiovascular control as well as some neurodegenerative disorders. In some species, they play an essential role in hibernation. One of the most exciting findings of the past decade is the opioid-receptor, especially DOR, mediated neuroprotection and cardioprotection. The upregulation of DOR expression and DOR activation increase the neuronal tolerance to hypoxic/ischemic stress. The DOR signal triggers (depending on stress duration and severity) different mechanisms at multiple levels to preserve neuronal survival, including the stabilization of homeostasis and increased pro-survival signaling (e.g., PKC-ERK-Bcl 2) and antioxidative capacity. In the heart, PKC and KATP channels are involved in the opioid receptor-mediated cardioprotection. The DOR-mediated neuroprotection and cardioprotection have the potential to significantly alter the clinical pharmacology in terms of prevention and treatment of life-threatening conditions like stroke and myocardial infarction. The main purpose of this article is to review the recent work done on opioids and their receptor functions. It shall provide an informative reference for better understanding the opioid system and further elucidation of the opioid receptor function from a physiological and pharmacological point of view.

Association between harm reduction intervention uptake and recent hepatitis C infection among people who inject drugs attending sites that provide sterile injecting equipment in Scotland

BACKGROUND

Prevalence of the hepatitis C virus (HCV) among people who inject drugs (PWID) in Scotland is high. The Scottish Government has invested significantly in harm reduction interventions with the goal of reducing HCV transmission among PWID. In evaluating the effectiveness of interventions, estimates of HCV incidence are essential.

METHODS

During 2008-2009, PWID were recruited from services providing sterile injecting equipment across mainland Scotland, completed an interviewer-administered questionnaire and provided a dried blood spot for anonymous anti-HCV and HCV-RNA testing. Recent infections were defined as anti-HCV negative and HCV-RNA positive. Logistic regression was undertaken to examine associations between recent HCV infection and self-reported uptake of methadone maintenance therapy (MMT) and injection equipment.

RESULTS

Fifty-four percent (1367/2555) of participants were anti-HCV positive. We detected 24 recent HCV infections, yielding incidence rate estimates ranging from 10.8 to 21.9 per 100 person-years. After adjustment for confounders, those with high needle/syringe coverage had reduced odds of recent infection (adjusted odds ratio [AOR] 0.32, 95% CI 0.10-1.00, p=0.050). In the Greater Glasgow & Clyde region only, we observed a reduced odds of recent infection among those currently receiving MMT, relative to those on MMT in the last six months but not currently (AOR 0.04, 95% CI 0.001-1.07, p=0.055). The effect of combined uptake of MMT and high needle/syringe coverage was only significant in unadjusted analyses (OR 0.34, 95% CI 0.12-0.97, p=0.043; AOR 0.48, 95% CI 0.16-1.48, p=0.203).

CONCLUSION

We report the first large-scale, national application of a novel method designed to determine incidence of HCV among PWID using a cross-sectional design. Subsequent sweeps of this survey will increase statistical power and allow us to gauge the impact of preventive interventions.

Medical and psychological risks and consequences of long-term opioid therapy in women

BACKGROUND

Long-term opioid use has increased substantially over the past decade for U.S. women. Women are more likely than men to have a chronic pain condition, to be treated with opioids, and may receive higher doses. Prescribing trends persist despite limited evidence to support the long-term benefit of this pain treatment approach.

PURPOSE

To review the medical and psychological risks and consequences of long-term opioid therapy in women.

METHOD

Scientific literature containing relevant keywords and content were reviewed.

RESULTS AND CONCLUSIONS

Long-term opioid use exposes women to unique risks, including endocrinopathy, reduced fertility, neonatal risks, as well as greater risk for polypharmacy, cardiac risks, poisoning and unintentional overdose, among other risks. Risks for women appear to vary by age and psychosocial factors may be bidirectionally related to opioid use. Gaps in understanding and priorities for future research are highlighted.

Opioids in chronic noncancer pain: more faces from the crowd

BACKGROUND

The use of opioids for chronic noncancer pain (CNCP) remains very controversial. There are several randomized controlled trials, mostly in neuropathic pain, reporting efficacy and safety in the short term, but more long-term data are needed. Randomized controlled trials may be limited in providing data about the patients who benefit from often high-dose opioids over the long term. The present article provides details of these patients and adds to a previous case series.

METHODS

The present article contains 17 case reports of 11 CNCP conditions (followed to 2011) selected to illustrate specific issues from a survey of 84 patients with intractable CNCP treated with opioids and followed every three months for a median of 11 years. The previous published survey of this group reported outcomes of pain severity, adverse effects, pain relief, satisfaction, mood, problematic opioid use, tolerance, physical dependency, functional status, health-related quality of life (HRQL), immune status and sexual function. The outcome measures for that study included a numerical rating scale for pain, the Hospital Anxiety and Depression Scale, the Brief Pain Inventory Interference Scale, the Pain Disability Index and, for HRQL, the Short-Form Health Survey 12 version 2. Most patients in the total sample reported 50% or greater relief and a moderate improvement in disability. Scores for functional status and HRQL were not severely affected. Problematic use, tolerance and serious adverse effects, including constipation, were not major issues. These selected patient reports were chosen, not to illustrate optimal results, but rather important aspects of the diagnoses, opioids and doses, the paucity of intolerable adverse effects, particular issues (concurrent addiction history, bipolar disorder and combination therapy), disease-specific and other outcomes and duration of follow-up with complex pain problems.

RESULTS

Opioids were found to be safe and useful in the long term for these particular patients, as well as in the larger group from which they originated.

INTERPRETATION

These 17 reports of patients with intractable CNCP treated with opioids with some success over many years puts a face on more of the participants in the larger survey of 84 subjects, suggesting that this approach is effective and safe for some patients over many years.

Cytokine profiles in high risk injection drug users suggests innate as opposed to adaptive immunity in apparent resistance to hepatitis C virus infection

A cohort of injection drug users (IDU) have been identified who despite a long history of IDU and sharing of injecting equipment remain seronegative and aviraemic for hepatitis C virus (HCV). They have been termed HCV exposed uninfected (EU). The study of potential innate or adaptive immune mechanisms of resistance to HCV infection in this group is of interest. The aim of this study was to determine the levels of a broad range of cytokines in serum of exposed, uninfected individuals to ascertain whether there is a specific cytokine profile associated with apparent resistance to HCV. Sera from 22 EU individuals were analysed for a range of cytokines and chemokines, and compared to 16 treatment-naive chronic HCV cases (HCV Ab+ RNA+), 16 individuals with spontaneous resolution of HCV (HCV-Ab+ and HCV-RNA-) and 10 healthy unexposed controls. EU subjects had strikingly higher levels of both IL-6 (on average more than 100-fold, P = 0.001) and IL-8 (on average more than 10-fold, P < 0.001) than the comparison groups. Additionally higher levels of tumour necrosis factor-alpha (TNF-α; on average up to threefold, P = 0.02) were seen in EU individuals. The levels of interferon-alpha (IFN-α) were upregulated in all HCV exposed groups in comparison to healthy controls (P = 0.013). Adaptive immune cytokine levels were no different between the groups. Cytokine profiling demonstrated raised levels of pro-inflammatory innate immune cytokines and chemokines in EU IDU, in particular interleukin-6 and interleukin-8. These findings suggest innate immune activation may be the key to prevention of infection in this cohort.

Outcomes associated with a cognitive-behavioral chronic pain management program implemented in three public HIV primary care clinics

In patients with HIV/AIDS, chronic pain is common and analgesics pose serious risks. Cognitive-behavioral therapies (CBT) provide an alternative. This study evaluated feasibility and impact of a CBT-based pain management program in three public primary care clinics for HIV patients. The program included a workbook and 12-weeks of group CBT sessions. HIV-positive patients with chronic moderate to severe pain were invited to participate in the program and were assessed at enrollment, 6, 12, and 24 weeks. Despite only moderate group attendance, program enrollment was associated with significant improvements in pain intensity, pain-related functioning, anxiety and acceptance, and mental health. At 24 weeks, effect sizes for pain outcomes were -0.83 for pain intensity and -0.43 for functioning. The pattern of change in outcomes was consistent with predictions based on cognitive-behavioral theory. Effects were observed at all clinics. Adding CBT-based pain management into primary care may provide important benefits for patients with HIV/AIDS.

G protein-coupled receptors as therapeutic targets for multiple sclerosis

G protein-coupled receptors (GPCRs) mediate most of our physiological responses to hormones, neurotransmitters and environmental stimulants. They are considered as the most successful therapeutic targets for a broad spectrum of diseases. Multiple sclerosis (MS) is an inflammatory disease that is characterized by immune-mediated demyelination and degeneration of the central nervous system (CNS). It is the leading cause of non-traumatic disability in young adults. Great progress has been made over the past few decades in understanding the pathogenesis of MS. Numerous data from animal and clinical studies indicate that many GPCRs are critically involved in various aspects of MS pathogenesis, including antigen presentation, cytokine production, T-cell differentiation, T-cell proliferation, T-cell invasion, etc. In this review, we summarize the recent findings regarding the expression or functional changes of GPCRs in MS patients or animal models, and the influences of GPCRs on disease severity upon genetic or pharmacological manipulations. Hopefully some of these findings will lead to the development of novel therapies for MS in the near future.

Interactive Effects of Morphine on HIV Infection: Role in HIV-Associated Neurocognitive Disorder

HIV epidemic continues to be a severe public health problem and concern within USA and across the globe with about 33 million people infected with HIV. The frequency of drug abuse among HIV infected patients is rapidly increasing and is another major issue since injection drug users are at a greater risk of developing HIV associated neurocognitive dysfunctions compared to non-drug users infected with HIV. Brain is a major target for many of the recreational drugs and HIV. Evidences suggest that opiate drug abuse is a risk factor in HIV infection, neural dysfunction and progression to AIDS. The information available on the role of morphine as a cofactor in the neuropathogenesis of HIV is scanty. This review summarizes the results that help in understanding the role of morphine use in HIV infection and neural dysfunction. Studies show that morphine enhances HIV-1 infection by suppressing IL-8, downregulating chemokines with reciprocal upregulation of HIV coreceptors. Morphine also activates MAPK signaling and downregulates cAMP response element-binding protein (CREB). Better understanding on the role of morphine in HIV infection and mechanisms through which morphine mediates its effects may help in devising novel therapeutic strategies against HIV-1 infection in opiate using HIV-infected population.

Opium use and mortality in Golestan Cohort Study: prospective cohort study of 50,000 adults in Iran

OBJECTIVES

To investigate the association between opium use and subsequent risk of death.

DESIGN

Prospective cohort study.

SETTING

The Golestan Cohort Study in north-eastern Iran collected detailed validated data on opium use and other exposures at baseline. Participants were enrolled between January 2004 and June 2008 and were followed to May 2011, with a follow-up success rate of over 99%.

PARTICIPANTS

50,045 participants aged 40-75 at baseline.

MAIN OUTCOMES

Mortality, all cause and major subcategories.

RESULTS

17% (n = 8487) of the participants reported opium use, with a mean duration of 12.7 years. During the follow-up period 2145 deaths were reported. The adjusted hazard ratio for all cause mortality associated with ever use of opium was 1.86 (95% confidence interval 1.68 to 2.06). Opium consumption was significantly associated with increased risks of deaths from several causes including circulatory diseases (hazard ratio 1.81) and cancer (1.61). The strongest associations were seen with deaths from asthma, tuberculosis, and chronic obstructive pulmonary disease (11.0, 6.22, and 5.44, respectively). After exclusion of people who self prescribed opium after the onset of major chronic illnesses, the associations remained strong with a dose-response relation.

CONCLUSION

Opium users have an increased risk of death from multiple causes compared with non-users. Increased risks were also seen in people who used low amounts of opium for a long period and those who had no major illness before use.

Percutaneous mechanical disc decompression using Dekompressor device: an appraisal of the current literature

OBJECTIVES

The objective of this study was to determine if the available literature answers the following questions: does percutaneous disc decompression using Dekompressor device relieve radicular pain caused by a small disc herniation? Is the duration of response stable and clinically worthwhile? Is relief of pain corroborated by improvements in physical and social function? Does relief of pain result in reduction in the use of other health care? Is there a risk of serious side effects or complications? DESIGN/SETTINGS: The study was designed as a narrative review and description of the available evidence, drawn from the databases of PubMed, EMBASE, and the Cochrane Library. Innovatively, the concept of the "context of the patient" was introduced in the assessment. It required the assessors to consider the alternatives the patients and their treating practitioners faced.

RESULTS

The literature search identified three nonrandomized clinical trials, and a single case series. All studies were reasonably rigorous in reporting relief of pain and the use of analgesics. Evidence with respect to physical functioning was scarce. Although investigators reported on the relief of pain, they lacked rigor when reporting associated outcome measures such as use of other health care and physical functioning.

CONCLUSIONS

Unfortunately, the context of a patient with persistent radicular pain caused by a small disc herniation is the lack of good alternatives to Dekompressor procedure. The moral question is whether Dekompressor is any less valid an option than perpetual opioids or discectomy. This question would be much easier to answer if the literature on Dekompressor was more rigorous and more compelling in its evidence.

Mu opioid receptor activation modulates Toll like receptor 4 in murine macrophages

Opioids have been shown to affect both innate and adaptive immunity. We previously showed that morphine affects the macrophage production of pro-inflammatory cytokines after LPS in a NFkB dependent manner. Toll like receptors (TLRs) play a crucial role in the signaling pathways which lead to NFkB activation. TLR4 is considered the Lipopolysaccaride (LPS) receptor. The data here presented show that, in murine macrophages, morphine impacts on the immune function acting on the early step of pathogen recognition. Morphine, when added to RAW 264.7 cells and when injected into mice (s.c. 20mg/kg) is in fact able to decrease TLR4 both at mRNA and protein level in RAW cells and peritoneal macrophages. In the same cells, the mu opioid receptor (MOR) antagonist Naltrexone increases TLR4 levels, thus suggesting a role of the endogenous opioid system in TLR4 regulation. The effect of the two drugs is moreover lost in case of co-administration. Experiments with MOR KO mice and with DAMGO (MOR specific agonist) confirm that the effect of morphine on TLR4 mRNA in peritoneal macrophages is due to the MOR activation. Moreover the effect on TLR4 is blocked by PTX thus indicating the involvement of a G(i) protein after MOR binding. This work unveils a clear link between MOR activation and TLR4, suggesting a new possible mechanism at the basis of the peripheral immunosuppressive effect of opioids.

Substance Abuse, Hepatitis C, and Aging in HIV: Common Cofactors that Contribute to Neurobehavioral Disturbances

Although the prevalence of neurocognitive disturbances among individuals with HIV has decreased in recent years, rates of impairment still remain high. This review presents findings from comorbid conditions that may contribute to further neurocognitive impairments in this already vulnerable population. We will focus on three co-factors that have received substantial attention in the neuroAIDS literature: drug use, hepatitis C co-infection (HCV), and aging. All three conditions commonly co-occur with HIV and likely interact with HIV in complex ways. Collectively, the extant literature suggests that drug use, HCV, and aging serve to worsen the neurocognitive profile of HIV through several overlapping mechanisms. A better understanding of how specific comorbidities interact with HIV may reveal specific phenotypes of HIV-associated neurocognitive disorder that may aid in the development of more targeted behavioral and pharmacological treatment efforts.

Interplaying factors that effect multiple sclerosis causation and sustenance

The author hypothesized that multiple sclerosis (MS) is a humoral autoimmune disease, caused by faulty interplay between myelin-specific, dimeric IgE, specifically competing non-IgE antibodies and IgE-triggered degranulating mast cells. The principal fault was believed to be insufficient quantity of protective, specific non-IgE antibodies. Also conjectured was the possibility of an unexpected and adverse immune suppression caused by none-MS pharmaceuticals being consumed by patients for their MS or for other conditions. To test both hypotheses, a mimotopic, peptide antigen-based, serum immunoassay was developed to measure dimer-bound IgE excess among MS patients, wherein the IgE specifically complexes with two or more myelin surface epitopes at an interval of 40–100 Angstroms, a separation critical for mast cell degranulation and cell damaging effect. MS test sensitivity and specificity, when analyzing five previously untreated patients for dimeric IgE presence, was 100%. In direct comparison, twenty age- and gender-matched female and male control subjects were test negative. Analysis of 35 multiple sclerosis patients, who were concomitantly being treated with potentially immunosuppressive pharmaceuticals, appeared to show the substances' negative effect upon MS causation, progression, or specific immunoassay performance. Therefore, MS is likely an autoimmune disease caused by IgE-mediated mast cell degranulation possibly in conjunction with immunosuppressive agents.

Epidemiologic and Molecular Pathophysiology of Chronic Opioid Dependence and the Place of Naltrexone Extended-Release Formulations in its Clinical Management

Naltrexone implants and depot injections (NI) are a novel form of treatment for opiate dependence (OD). Major questions relate to their absolute and relative efficacy and safety. Opportunely, six recent clinical trial data from several continents have uniformly provided dramatic evidence of the potent, dose-related and highly significant efficacy of NI, with minimal or manageable accompanying toxicity and safety concerns. The opiate-free lifestyle is attained significantly more often with NI adjusted O.R. = 6.00 (95% C.I. 3.86–9.50), P < 10⁻¹⁰. Other drug use and drug craving are also rapidly reduced. The optimum manner in which to commence NI remains to be established. Of particular relevance is the relative safety of NI compared to the chronic opiate agonists (COA) usually employed, as the long-term toxicity of COA is only just being elucidated. Large population-based studies have found elevated rates of cardiovascular disease, six cancers, liver and respiratory disease, and all-cause mortality in COA. Whilst opiates have been shown to trigger numerous molecular pathways, the most interesting is the demonstration that the opiate morphinan’s nucleus binds to the endotoxin groove of the TLR4-MD2 heterodimer. This has the effect of triggering a low grade endotoxaemic-like state, which over time may account for these protean clinical findings, an effect which is reversed by opiate antagonists. This emerging evidence suggests an exciting new treatment paradigm for OD and a corresponding increase in the role of NI in treatment.

Chronic non-cancer pain and the long-term efficacy and safety of opioids: Some blind men and an elephant?

Background

The use of opioids for chronic non-cancer pain (CNCP) remains very controversial. There are a number of randomized controlled trials (RCTs) showing efficacy and safety in the short-term, but long-term data are limited.

Methods

This article contains 10 case reports (followed to 2011) that were selected from a survey of 84 patients with intractable CNCP treated with opioids and followed every 3 months now for a median of 10 years. The previous published survey of this group reported outcomes of pain severity, adverse effects, pain relief, satisfaction, mood, problematic opioid use, tolerance, physical dependency, functional status, health-related quality of life (HRQL), immune status and sexual function. The outcome measures for that study included a numerical rating scale (NRS) for pain, Hospital Anxiety and Depression Scale (HADS), the Brief Pain Inventory Interference Scale (BPI-I), the Pain Disability Index (PDI), and for Health Related Quality of Life (HRQL) the Short Form Health Survey 12 version 2 (SF12v2). These selected patient reports were chosen to illustrate some important aspects of the diagnostic categories of CNCP, the opioids and doses used, particular issues (concurrent addiction history, bipolar disorder, and combination therapy), disease-specific and other outcomes (pain severity and relief, adverse effects, mood, function) and duration of follow-up with complex pain problems.

Results

Opioids were found to be safe and effective in the long-term for these particular patients, as well as in the larger group from which they originate. Most patients in the total sample reported 50% or greater relief and a moderate improvement in disability. Scores for functional status and HRQL were not severely affected (PDI and BPI-I ratings moderate or less and SF12v2 slightly below normative values for age). Problematic use, tolerance, and serious adverse effects including constipation were not major issues.

Conclusion

These 10 reports of patients with intractable CNCP treated with opioids with some success over many years put a face on some of the participants in the larger survey of 84 suggesting that this approach is effective and safe for some patients over many years.

Implications

These data may not be generalizable to a larger population of patients with CNCP because of the probable selection of patients who benefit and who do not have intolerable adverse effects.

Role of the mu-opioid receptor in opioid modulation of immune function

Endogenous opioids are synthesized in vivo to modulate pain mechanisms and inflammatory pathways. Endogenous and exogenous opioids mediate analgesia in response to painful stimuli by binding to opioid receptors on neuronal cells. However, wide distribution of opioid receptors on tissues and organ systems outside the CNS, such as the cells of the immune system, indicate that opioids are capable of exerting additional effects in the periphery, such as immunomodulation. The increased prevalence of infections in opioid abuser-based epidemiological studies further highlights the immunosuppressive effects of opioids. In spite of their many debilitating side effects, prescription opioids remain a gold standard for treatment of chronic pain. Therefore, given the prevalence of opioid use and abuse, opioid-mediated immune suppression presents a serious concern in our society today. It is imperative to understand the mechanisms by which exogenous opioids modulate immune processes. In this review, we will discuss the role of opioid receptors and their ligands in mediating immune-suppressive functions. We will summarize recent studies on direct and indirect opioid modulation of the cells of the immune system, as well as the role of opioids in exacerbation of certain disease states.

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.

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.

Virtual reality pain control during burn wound debridement of combat-related burn injuries using robot-like arm mounted VR goggles

BACKGROUND

This is the first controlled study to explore whether adjunctive immersive virtual reality (VR) can reduce excessive pain of soldiers with combat-related burn injuries during wound debridement.

METHODS

Patients were US soldiers burned in combat attacks involving explosive devices in Iraq or Afghanistan. During the same wound care session using a within-subject experimental design, 12 patients received half of their severe burn wound cleaning procedure (~6 minutes) with standard of care pharmacologies and half while in VR (treatment order randomized). Three 0 to 10 Graphic Rating Scale pain scores for each of the treatment conditions served as the primary variables.

RESULTS

Patients reported significantly less pain when distracted with VR. "Worst pain" (pain intensity) dropped from 6.25 of 10 to 4.50 of 10. "Pain unpleasantness" ratings dropped from "moderate" (6.25 of 10) to "mild" (2.83 of 10). "Time spent thinking about pain" dropped from 76% during no VR to 22% during VR. Patients rated "no VR" as "no fun at all" (<1 of 10) and rated VR as "pretty fun" (7.5 of 10). Follow-up analyses showed VR was especially effective for the six patients who scored 7 of 10 or higher (severe to excruciating) on the "worst pain" (pain intensity) ratings.

CONCLUSIONS

These preliminary results provide the first evidence from a controlled study that adjunctive immersive VR reduced pain of patients with combat-related burn injuries during severe burn wound debridement. Pain reduction during VR was greatest in patients with the highest pain during no VR. These patients were the first to use a unique custom robot-like arm mounted VR goggle system.

Agent-based dynamic knowledge representation of Pseudomonas aeruginosa virulence activation in the stressed gut: Towards characterizing host-pathogen interactions in gut-derived sepsis

Background

There is a growing realization that alterations in host-pathogen interactions (HPI) can generate disease phenotypes without pathogen invasion. The gut represents a prime region where such HPI can arise and manifest. Under normal conditions intestinal microbial communities maintain a stable, mutually beneficial ecosystem. However, host stress can lead to changes in environmental conditions that shift the nature of the host-microbe dialogue, resulting in escalation of virulence expression, immune activation and ultimately systemic disease. Effective modulation of these dynamics requires the ability to characterize the complexity of the HPI, and dynamic computational modeling can aid in this task. Agent-based modeling is a computational method that is suited to representing spatially diverse, dynamical systems. We propose that dynamic knowledge representation of gut HPI with agent-based modeling will aid in the investigation of the pathogenesis of gut-derived sepsis.

Methodology/Principal Findings

An agent-based model (ABM) of virulence regulation in Pseudomonas aeruginosa was developed by translating bacterial and host cell sense-and-response mechanisms into behavioral rules for computational agents and integrated into a virtual environment representing the host-microbe interface in the gut. The resulting gut milieu ABM (GMABM) was used to: 1) investigate a potential clinically relevant laboratory experimental condition not yet developed - i.e. non-lethal transient segmental intestinal ischemia, 2) examine the sufficiency of existing hypotheses to explain experimental data - i.e. lethality in a model of major surgical insult and stress, and 3) produce behavior to potentially guide future experimental design - i.e. suggested sample points for a potential laboratory model of non-lethal transient intestinal ischemia. Furthermore, hypotheses were generated to explain certain discrepancies between the behaviors of the GMABM and biological experiments, and new investigatory avenues proposed to test those hypotheses.

Conclusions/Significance

Agent-based modeling can account for the spatio-temporal dynamics of an HPI, and, even when carried out with a relatively high degree of abstraction, can be useful in the investigation of system-level consequences of putative mechanisms operating at the individual agent level. We suggest that an integrated and iterative heuristic relationship between computational modeling and more traditional laboratory and clinical investigations, with a focus on identifying useful and sufficient degrees of abstraction, will enhance the efficiency and translational productivity of biomedical research.

Morphine and tumor growth and metastasis

Morphine is an analgesic widely used to alleviate cancer pain. In addition, the perioperative management of pain in cancer surgery patients most often includes opioids. However, there are reports that these drugs may alter cancer recurrence or metastasis. Several mechanisms have been proposed, such as the modulation of the immune response or cellular pathways that control the survival and migratory behavior of cancer cells. The published literature, however, presents some discrepancies, with reports suggesting that opioids may either promote or prevent the spread of cancer. It is of great importance to determine whether opioids, in particular the most widely used, morphine, may increase the risk of metastasis when used in cancer surgery. This review examines the available data on the effects of morphine which influence cancer metastasis or recurrence, including immunomodulation, tumor cell aggressiveness, and angiogenesis, with special emphasis on recently published clinical and laboratory based studies. We further discuss the parameters that may explain the difference between reports on the effects of morphine on cancer.

[Limits of pain treatment: medical and judicial aspects]

Medical principles of pain treatment are generally in line with the judicial principles. To relieve pain is one of the fundamentals of medicine and this has also been acknowledged by the Federal Court in Germany. It is criminal bodily harm, when a physician denies a possible pain treatment. Whereas courts clearly see an obligation to basic and continuing education in pain diagnosis and therapy, pain is still not represented in the German licensing regulations for physicians. Only palliative medicine has been added to the obligatory curriculum. Very similar pain is not mandatory in many clinical disciplines leaving physicians without the needed knowledge to treat pain. The need for interdisciplinary treatment is not yet acknowledged sufficiently, although meanwhile chronic pain is regarded as a bio-psycho-social illness.Since 2009 the advance directive is regulated by law. However, still many physicians are unaware that not only the position of the patient but also of the relatives have been strengthened. In 2010 the Federal Court has pronounced a judgment allowing "passive euthanasia" in certain conditions but prohibiting any active handling even in line with the patient's will. This is also in line with the European Human Rights Convention. The judicial unpunished assisted suicide has provoked an ethical discussion within the medical profession. However, what is not illegal is not automatically accepted as ethical handling for physicians. Palliative medicine is at least one alternative in this discussion.

Does sleep deprivation and morphine influence wound healing?

The contrast between present-day sleep habits and those of the pre-industrial era are quite evident. One study recent has shown that the amount of sleep has decreased 2 h per night over the past 50 years. Such sleep curtailment, ubiquitous in the modern lifestyle, inflicts adverse repercussions upon health and well being. Investigations examining the relationship between stress and the skin have shown that different types of stress affect the healing process. Morphine is an immunosuppressive drug, and when it is used chronically, it can lead to an increased incidence of infections and a delay in the healing process. Therefore, our hypothesis is that the lack of sleep associated with chronic treatment with morphine is detrimental to the healing of the skin in the animal model we have adopted. Thus, it is important that future studies consider the paradigm of sleep curtailment when investigating the mechanisms involved in the process of skin healing in individuals who are dependent on morphine.

Combining ketamine and virtual reality pain control during severe burn wound care: one military and one civilian patient

BACKGROUND

US soldiers injured in Iraq, and civilian burn trauma patients are treated at the US Army Institute of Surgical Research. Burn patients experience extreme pain during wound care, and they typically receive opioid analgesics and anxiolytics for debridement. Virtual Reality (VR) has been applied as an adjunct to opioid analgesics for procedural pain. We describe the first use of ketamine combined with immersive VR to reduce excessive pain during wound care.

CASE REPORT

A 21-year-old male US Army soldier stationed in Iraq, and a 41-year-old civilian male sustained a 13% and 50% total body surface area (TBSA) burn, respectively. Each patient received 40 mg ketamine intraveneous (IV) for wound care. Using a within-subject design, nurses conducted half of a painful segment of wound care treatments with no VR and the other half with immersive VR. Graphic pain rating scores for each of the two treatment conditions served as the dependent variables.

RESULTS

Compared to ketamine + no VR, both patients reported less pain during ketamine + VR for all three pain ratings. Both patients rated wound care during no VR as "no fun at all", but those same patients rated wound care during virtual reality as either "pretty fun" or "extremely fun", and rated nausea as either "mild" or "none".

CONCLUSIONS

Results from these first two cases suggest that a moderate dose of ketamine combined with immersive virtual reality distraction may be an effective multimodal analgesic regimen for reducing acute procedural pain during severe burn wound cleaning.

Current knowledge of buprenorphine and its unique pharmacological profile

Despite the increasing clinical use of transdermal buprenorphine, questions have persisted about the possibility of a ceiling effect for analgesia, its combination with other μ-opioid agonists, and the reversibility of side effects. In October 2008, a consensus group of experts met to review recent research into the pharmacology and clinical use of buprenorphine. The objective was to achieve consensus on the conclusions to be drawn from this work. It was agreed that buprenorphine clearly behaves as a full μ-opioid agonist for analgesia in clinical practice, with no ceiling effect, but that there is a ceiling effect for respiratory depression, reducing the likelihood of this potentially fatal adverse event. This is entirely consistent with receptor theory. In addition, the effects of buprenorphine can be completely reversed by naloxone. No problems are encountered when switching to and from buprenorphine and other opioids, or in combining them. Buprenorphine exhibits a pronounced antihyperalgesic effect that might indicate potential advantages in the treatment of neuropathic pain. Other beneficial properties are the compound's favorable safety profile, particularly in elderly patients and those with renal impairment, and its lack of effect on sex hormones and the immune system. The expert group agreed that these properties, as well as proven efficacy in severe pain and favorable tolerability, mean that buprenorphine can be considered a safe and effective option for treating chronic cancer and noncancer pain.

Downregulation of constitutive and cytokine-induced complement 3 expression by morphine in rat astrocytes

BACKGROUND

The effect of opioids on inflammation and immune responses is an important subject of investigation because immunoregulatory cytokines are produced in the central nervous system and opioid receptors are widespread in these cells.

OBJECTIVES

The aim of this study was to evaluate the immunomodulatory effect of morphine on the C3 expression (both constitutive and proinflammatory cytokine-induced C3 expression) in primary rat astrocytes.

METHODS

Primary rat astrocytes were untreated or treated with morphine in different concentrations (10(-6) to 10(-2) M) before incubation without or with 5 U/mL tumor necrosis factor-α (TNF-α), and C3 protein and mRNA expressions were measured. Similarly, astrocytes were treated with 10(-3) M morphine and stimulated with other proinflammatory cytokines, including 10 ng/mL interleukin-8 (IL-8) and 5 U/mL IL-1β. Astrocytes were exposed to 10(-5) M naloxone for 2 hours before adding morphine, and TNF-α and C3 protein was measured. Tumor growth factor-β (TGF-β) was measured from the supernatants of each proinflammatory cytokine.

RESULTS

All results are expressed as mean percentages of C3 production by normalizing C3 without morphine or any cytokine treatment as 100%. Constitutive C3 protein production was decreased at morphine 10(-3) M (57.2%) and 10(-2) M (30.1%). Pretreatment with morphine suppressed induction of C3 expression at both the protein and mRNA levels in astrocytes stimulated with TNF-α, IL-8, and IL-1β (P < 0.05) in a dose-dependent manner. The inhibition of C3 protein production by morphine (10(-3) M; 33%) was partially attenuated by naloxone (52.0%) (P < 0.05). The pretreatment of astrocytes with morphine (10(-3) M) before stimulation with TNF-α, IL-8, and IL-1β increased by 33% (P < 0.05), decreased by 15.2% (P < 0.05), and did not change the production of TGF-β protein, respectively.

CONCLUSIONS

Morphine downregulated both constitutive and proinflammatory cytokine-induced C3 expression of astrocytes at the transcriptional level, but not in a cytokine-specific manner.

A population-based cohort study on chronic pain: the role of opioids

OBJECTIVES

The aims of this study were 2-fold: (1) to investigate the consequences of opioid use in individuals with chronic pain in the Danish population, and (2) to investigate the development of and recovery from chronic pain from 2000 to 2005.

METHODS

Data derived from the Danish Health Interview Survey in 2000, which were linked on the individual level with register-based follow-up data. The survey was based on a county-stratified random sample of 16,684 individuals, out of which 10,434 individuals (62.5%) completed a face-to-face interview and returned a self-administered questionnaire. In addition, a subsample of the sample in 2000 was reinvited to a follow-up survey in 2005. In total, 3649 individuals (61.7%) of this subsample completed the interview and returned the questionnaire at baseline in 2000. At follow-up, 2354 of these participants completed the interview and returned the self-administered questionnaire. Respondents with cancer diagnosis were excluded from all analyses. Respondents with chronic pain were identified as having chronic/long-lasting pain more than 6 months.

RESULTS AND DISCUSSION

The annual incidence for the development of and the recovery from chronic pain was 2.7% and 9.4%, respectively. Increasing age up to 64 years, short education, poor self-rated health, high body mass index, and physical strain at work were predictors of chronic pain. The odds of recovery from chronic pain were almost 4 times higher among individuals not using opioids compared with individuals using opioids. In addition, use of strong opioids was associated with poor health-related quality of life. Furthermore, the results indicated that individuals with chronic pain using strong opioids pain had a higher risk of death than individuals without chronic pain (HR: 1.67; 95% CI: 1.03-2.70). However, this study cannot exclude disease severity as the primary cause of increased mortality.

Morphine decreases early peritoneal innate immunity responses in Swiss-Webster and C57BL6/J mice through the inhibition of mast cell TNF-α release

OBJECTIVE

To characterize immunosuppressive effects of morphine on the early innate immunity response of cytokine production in peritoneal cavity after LPS challenge.

METHODS

The effects of a single i.p. administration of morphine (3.1 or 31 mg/kg) on LPS-induced tumor necrosis factor α (TNF-α) and monocyte chemoattractant protein-1 (CCL2) intraperitoneal release was tested in Swiss-Webster, C57BL/6J, mast cell deficient Kit(Wsh/Wsh) (W-sh) and mast cell reconstituted (W-sh-rec) mice.

RESULTS

Morphine was found to inhibit LPS-induced TNF-α but not CCL2 release in the peritoneal cavity. Studies on mast cell deficient and reconstituted mice indicate that resident mast cells mediate selective morphine immunosuppression in the peritoneal cavity.

Increased degranulation of natural killer cells during acute HCV correlates with the magnitude of virus-specific T cell responses

BACKGROUND & AIMS

Natural killer (NK) cells provide early defense against viral infections by killing infected cells and producing cytokines that inhibit viral replication. NK cells also interact with dendritic cells (DCs) and this reciprocal interaction regulates both innate and adaptive immunity. Genetic studies have suggested that NK cell activity is a determinant of HCV infectious outcome but a functional correlation has not been established. We hypothesized that increased NK cell activity during acute HCV infection correlates with spontaneous viral clearance.

METHODS

We used multiparametric flow cytometry to monitor longitudinally the phenotype and the activity of NK cells in a cohort of intravenous drug users following HCV exposure. Three groups were studied: acute HCV with chronic evolution (n = 13), acute resolving HCV (n = 11), and exposed un-infected individuals (n = 10). We examined the expression of several NK cell-activating and -inhibiting receptors, IFN-γ production and CD107a degranulation upon stimulation, and the kinetics of NK cell responses relative to T cell responses.

RESULTS

We observed decreased expression of the inhibitory NKG2A receptor in NK cells following spontaneous HCV clearance. In addition, we observed increased NK cell degranulation during acute HCV irrespective of infectious outcome. NK cell peak responses preceded or coincided with peak T cell responses. Furthermore, NK cell degranulation correlated with the magnitude of HCV-specific T cells.

CONCLUSIONS

Our results demonstrate that NK cells are activated during acute HCV regardless of infection outcome and may play an indirect role through induction and priming of T cell responses.

Effect of anaesthetic technique and other perioperative factors on cancer recurrence

Surgical excision is the mainstay of treatment for potentially curable solid tumours. Metastatic disease is the most important cause of cancer-related death in these patients. The likelihood of tumour metastases depends on the balance between the metastatic potential of the tumour and the anti-metastatic host defences, of which cell-mediated immunity, and natural killer cell function in particular, is a critical component. It is increasingly recognized that anaesthetic technique and other perioperative factors have the potential to effect long-term outcome after cancer surgery. Surgery can inhibit important host defences and promote the development of metastases. Anaesthetic technique and drug choice can interact with the cellular immune system and effect long-term outcome. The potential effect of i.v. anaesthetics, volatile agents, local anaesthetic drugs, opiates, and non-steroidal anti-inflammatory drugs are reviewed here. There is particular interest at present in the effect of regional anaesthesia, which appears to be beneficial. Retrospective analyses have shown an outcome benefit for paravertebral analgesia for breast cancer surgery and epidural analgesia for prostatectomy. Blood transfusion, pain, stress, and hypothermia are other potentially important perioperative factors to consider.

Substance use and women's health

Scientific findings show that substance abuse in women yields a higher risk of a variety of health problems than substance abuse in men. Research suggests that women experience addiction telescoping when they abuse alcohol, tobacco, specific stimulants, and possibly opioids. Medical side effects also develop more rapidly in women than men when they abuse many substances. Cancer and cardiac complications, specifically, pose a significant threat for women who abuse almost all types of substances. However, the physical consequences are not the only ones women suffer when they engage in substance abuse. Research on substance abuse in women ties opioids to mood and anxiety disorders, heroin to neurological deficiencies, cocaine to immune system suppression, and alcohol to intimate partner abuse. Additionally, female substance abusers, on average, have a lower level of education and lower rates of employment. In light of these gender-specific concerns, physicians should give particular consideration to detecting substance abuse in women.

Long-term intrathecal morphine and bupivacaine upregulate MOR gene expression in lymphocytes

BACKGROUND

Several studies have shown that opioids may suppress the immune system either by binding to mu-opioid receptors (MOR) expressed in immune cells or by activating these receptors within the central nervous system.

OBJECTIVE

To assess the level of lymphocyte expression of MOR mRNA in patients with chronic non-cancer pain, who were treated with intrathecal morphine or with morphine plus bupivacaine via an intrathecal drug delivery system, and to investigate whether intrathecal morphine and the associated local anesthetic administration influences lymphocyte subpopulations.

METHODS

In total, 29 people [10 controls (age range 59-85 years) and 19 patients (age range 47-89 years) with various chronic non-malignant pain conditions] were enrolled in the study. MOR mRNA levels were evaluated in peripheral lymphocytes, and lymphocyte subsets were determined by direct immunofluorescence using flow cytometry.

RESULTS

After 12 months of treatment with intrathecal morphine (1.5-4 mg/day), there was an increase in MOR mRNA levels in lymphocytes of 65% compared with controls and 47% with pretreatment values. Even higher levels (increase of 142% compared with controls and 135% with pretreatment values) were observed in the patients treated with morphine plus bupivacaine (0.2-0.4 mg/day). Elevation of MOR mRNA levels was confirmed in patients after 24 months of treatment. At this time point, the percentage of natural killer cells was significantly decreased.

CONCLUSION

This preliminary study suggests that opioids must be used with care in patients who are already immunosuppressed by disease or by other, concurrently administered drugs.

The long-term safety and efficacy of opioids: a survey of 84 selected patients with intractable chronic noncancer pain

BACKGROUND

The use of opioids for chronic noncancer pain (CNCP) remains controversial. Despite a number of randomized controlled trials showing efficacy and safety in the short term, long-term data are limited.

OBJECTIVE

To survey a selected cohort of patients with intractable CNCP with regard to long-term efficacy and safety of opioids.

METHODS

The present study reports long-term results from a survey of 84 patients with CNCP. The majority of patients had neuropathic pain, were treated with opioids and were followed every three months for a median of 8.4 years. Outcomes examined were pain severity, adverse effects, pain relief, satisfaction, mood, problematic opioid use, tolerance, physical dependency, functional status, health-related quality of life, immune status, sexual function, morbidity and mortality. Measures included a numerical rating scale, the Hospital Anxiety and Depression Scale, Brief Pain Inventory interference scale, Pain Disability Index and Short-Form Health Survey 12, version 2.

RESULTS AND CONCLUSIONS

Both long- and short-acting opioids were reported to be effective, with few significant long-term adverse effects in many subjects in the present selected cohort. The majority of patients reported at least 50% or greater pain relief and a moderate improvement in disability. Functional status and health-related quality of life scores were not severely affected. Problematic opioid use, tolerance and serious adverse effects, including constipation, were not major issues. The authors emphasize that the results obtained in the present selected group may not be generalizable to all CNCP patients in whom opioids are being initiated.

The impact of open reduction internal fixation on acute pain management in unstable pelvic ring injuries

BACKGROUND

The management of unstable pelvic ring injuries is complex. Displacement is a clear indication for surgical intervention. However, reduction of acute pain after stabilization may have substantial clinical benefits and affect management decisions. The purpose of this study was to determine the impact of operative fixation of unstable pelvic ring injuries in diminishing acute pain.

METHODS

During a 33-month period, 70 patients with isolated pelvic ring injuries were managed at a Level-1 trauma center and retrospectively reviewed. On the basis of clinical and radiographic instability, 38 patients were managed surgically and formed the study group. Pain was assessed using visual analog scales and narcotic consumption during the index hospitalization.

RESULTS

In the operative group, visual analog scale scores decreased 48% after fixation from 4.71 +/- 1.8 preoperatively to 2.85 +/- 0.8 postoperatively (p < 0.001). Concomitantly, narcotic requirements decreased 25% from 2.26 mg morphine per hour preoperatively to 1.71 mg morphine per hour postoperatively (p = 0.024). The mean total length of hospital stay was 5.6 days (SD, 1.2 days), and the postoperative length of hospital stay was 4.7 days (SD, 1.2 days).

CONCLUSIONS

Operative reduction and fixation of unstable pelvic ring injuries significantly decreases acute pain. This has substantial physiologic benefits, particularly by improving mobilization, and should be an additional factor when determining surgical indication and timing.

Opioid pharmaceuticals and addiction: the issues, and research directions seeking solutions

There are few pharmaceuticals superior to opiates for the treatment of pain. However, with concerns of addiction, withdrawal and questionable efficacy for all types of pain, these compounds are far from a magical panacea for pain-relief. As it is unlikely that other classes of compounds will supersede the opioids in the very near future, it is important to both optimize current opioid therapies and curb the astounding diversion of opioids from their intended analgesic use to non-medical abuse. In optimizing opioid therapeutics it is necessary to enhance the clinical awareness of the benefits of treating pain and combine this with aggressive strategies to reduce diversion for non-medical use. At the heart of the issue of opioid misuse is the role of opioid systems in the reward circuitry, and the adaptive processes associated with repetitive opioid use that manifest during withdrawal. Emerging pharmacological insights of opioid receptors will be reviewed that provide future hope for developing opioid-based analgesics with reduced addictive properties and perhaps, reduced opponent processes. In addition, with the increased understanding of nociceptive circuitry and the molecules involved in transmitting pain, new therapeutic targets have become evident that may result in effective analgesics either alone or in combination with current opioid therapies.

Upregulation of SOCS-3 and PIAS-3 impairs IL-12-mediated interferon-gamma response in CD56 T cells in HCV-infected heroin users

Background

CD56⁺ T cells are abundant in liver and play an important role in host innate immunity against viral infections, including hepatitis C virus (HCV) infection, a common infection among heroin abusers. We thus investigated the in vivo impact of heroin use or heroin use plus HCV infection on the CD56⁺ T cell frequency and function.

Methodology/Principal Findings

A total of 37 heroin users with (17) or without (20) HCV infection and 17 healthy subjects were included in the study. Although there was no significant difference in CD56⁺ T cell frequency in PBMCs among three study groups, CD56⁺ T cells isolated from the heroin users had significantly lower levels of constitutive interferon-gamma (IFN-γ) expression than those from the normal subjects. In addition, when stimulated by interleukin (IL)-12, CD56⁺ natural T cells from HCV-infected heroin users produced significantly lower levels of IFN-γ than those from the normal subjects. This diminished ability to produce IFN-γ by CD56⁺ T cells was associated with the increased plasma HCV viral loads in the HCV-infected heroin users. Investigation of the mechanisms showed that although heroin use or heroin use plus HCV infection had little impact on the expression of the key positive regulators (IL-12 receptors, STAT-1, 3, 4, 5, JAK-2, and TYK-2) in IL-12 pathway, heroin use or heroin use plus HCV infection induced the expression of suppressor of cytokine signaling protein-3 (SOCS-3) and protein inhibitors of activated STAT-3 (PIAS-3), two key inhibitors of IL-12 pathway.

Conclusion/Significance

These findings provide compelling in vivo evidence that heroin use or heroin use plus HCV infection impairs CD56⁺ T cell-mediated innate immune function, which may account for HCV infection and persistence in liver.