Acute pain the immune system and opioimmunosuppression

Dynorphin 1-17 and Its N-Terminal Biotransformation Fragments Modulate Lipopolysaccharide-Stimulated Nuclear Factor-kappa B Nuclear Translocation, Interleukin-1beta and Tumor Necrosis Factor-alpha in Differentiated THP-1 Cells

Dynorphin 1–17, (DYN 1–17) opioid peptide produces antinociception following binding to the kappa-opioid peptide (KOP) receptor. Upon synthesis and release in inflamed tissues by immune cells, DYN 1–17 undergoes rapid biotransformation and yields a unique set of opioid and non-opioid fragments. Some of these major fragments possess a role in immunomodulation, suggesting that opioid-targeted therapeutics may be effective in diminishing the severity of inflammatory disorders. This study aimed to examine the immunomodulatory effects of DYN 1–17 and major N-terminal fragments found in the inflammatory environment on nuclear factor-kappaB/p65 (NF-κB/p65) nuclear translocation and the release of interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) from lipopolysaccharide (LPS)-stimulated, differentiated THP-1 cells. The results demonstrate that NF-κB/p65 nuclear translocation was significantly attenuated following treatment with DYN 1–17 and a specific range of fragments, with the greatest reduction observed with DYN 1–7 at a low concentration (10 nM). Antagonism with a selective KOP receptor antagonist, ML-190, significantly reversed the inhibitory effects of DYN 1–17, DYN 1–6, DYN 1–7 and DYN 1–9, but not other DYN 1–17 N-terminal fragments (DYN 1–10 and 1–11) on NF-κB/p65 nuclear translocation. DYN 1–17 and selected fragments demonstrated differential modulation on the release of IL-1β and TNF-α with significant inhibition observed with DYN 1–7 at low concentrations (1 nM and 10 pM). These effects were blocked by ML-190, suggesting a KOP receptor-mediated pathway. The results demonstrate that DYN 1–17 and certain N-terminal fragments, produced in an inflamed environment, play an anti-inflammatory role by inhibiting NF-κB/p65 translocation and the subsequent cytokine release through KOP receptor-dependent and independent pathways.

The effectiveness of buprenorphine for treating cancer pain: an abridged Cochrane review

OBJECTIVES

To assess the effectiveness and tolerability of buprenorphine for cancer pain in adults and children.

METHODS

We searched CENTRAL, MEDLINE, EMBASE, ISI Web of Science, ISI BIOSIS, ClinicalTrials.gov, metaRegister of Controlled Trials, WHO International Clinical Trials Registry Platform and the Proceedings of the Congress of the European Federation of International Association for the Study of Pain to early 2015.

RESULTS

We included 19 randomised controlled trials comparing buprenorphine with placebo, buprenorphine or another active drug for cancer pain. The trials included 1421 patients and examined 16 different intervention comparisons. Of the 11 studies that compared buprenorphine to another drug, 5, 3 and 3 studies, respectively, found that buprenorphine was superior, no different or inferior to the alternative treatment in side effects profile or patient preference/acceptability. Pain intensity ratings did not differ significantly between intramuscular buprenorphine and buprenorphine suppository, although intramuscular treatment was associated with more adverse events (1 study). One study found faster onset of pain relief after sublingual than subdermal buprenorphine, with similar analgesia duration and adverse event rates. 2 studies found transdermal buprenorphine superior to placebo, whereas a third study found no difference between placebo and different doses of transdermal buprenorphine. No clear dose-response relationship was found for transdermal buprenorphine. The quality of this evidence base was limited by under-reporting, small sample sizes and attrition.

CONCLUSIONS

Buprenorphine might be considered as a fourth-line option compared with the more standard therapies of morphine, oxycodone and fentanyl, and even then it would only be suitable for some patients.

Buprenorphine for neuropathic pain in adults

BACKGROUND

Opioid drugs, including buprenorphine, are commonly used to treat neuropathic pain, and are considered effective by some professionals. Most reviews have examined all opioids together. This review sought evidence specifically for buprenorphine, at any dose, and by any route of administration. Other opioids are considered in separate reviews.

OBJECTIVES

To assess the analgesic efficacy of buprenorphine for chronic neuropathic pain in adults, and the adverse events associated with its use in clinical trials.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and EMBASE from inception to 11 June 2015, together with reference lists of retrieved papers and reviews, and two online study registries.

SELECTION CRITERIA

We included randomised, double-blind studies of two weeks' duration or longer, comparing any oral dose or formulation of buprenorphine with placebo or another active treatment in chronic neuropathic pain.

DATA COLLECTION AND ANALYSIS

Two review authors independently searched for studies, extracted efficacy and adverse event data, and examined issues of study quality. We did not carry out any pooled analyses.

MAIN RESULTS

Searches identified 10 published studies, and one study with results in ClinicalTrials.gov. None of these 11 studies satisfied our inclusion criteria, and so we included no studies in the review.

AUTHORS' CONCLUSIONS

There was insufficient evidence to support or refute the suggestion that buprenorphine has any efficacy in any neuropathic pain condition.

Buprenorphine for treating cancer pain

BACKGROUND

Many patients with cancer experience moderate to severe pain that requires treatment with strong analgesics. Buprenorphine, fentanyl and morphine are examples of strong opioids used for cancer pain relief. However, strong opioids are ineffective as pain treatment in all patients and are not well-tolerated by all patients. The aim of this Cochrane review is to assess whether buprenorphine is associated with superior, inferior or equal pain relief and tolerability compared to other analgesic options for patients with cancer pain.

OBJECTIVES

To assess the effectiveness and tolerability of buprenorphine for pain in adults and children with cancer.

SEARCH METHODS

We searched CENTRAL (the Cochrane Library) issue 12 or 12 2014, MEDLINE (via OVID) 1948 to 20 January 2015, EMBASE (via OVID) 1980 to 20 January 2015, ISI Web of Science (SCI-EXPANDED & CPCI-S) to 20 January 2015, ISI BIOSIS 1969 to 20 January 2015. We also searched ClinicalTrials.gov (http://clinicaltrials.gov/; metaRegister of Controlled Trials (mRCT) (http://www.controlled-trials.com/mrct/), the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) search portal (http://apps.who.int/trialsearch/) and the Proceedings of the Congress of the European Federation of International Association for the Study of Pain (IASP; via European Journal of Pain Supplements) on 16 February 2015. We checked the bibliographic references of identified studies as well as relevant studies and systematic reviews to find additional trials not identified by the electronic searches. We contacted authors of included studies for other relevant studies.

SELECTION CRITERIA

We included randomised controlled trials, with parallel-group or crossover design, comparing buprenorphine (any formulation and any route of administration) with placebo or an active drug (including buprenorphine) for cancer background pain in adults and children.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data pertaining to study design, participant details (including age, cancer characteristics, previous analgesic medication and setting), interventions (including details about titration) and outcomes, and independently assessed the quality of the included studies according to standard Cochrane methodology. As it was not feasible to meta-analyse the data, we summarised the results narratively. We assessed the overall quality of the evidence for each outcome using the GRADE approach.

MAIN RESULTS

In this Cochrane review we identified 19 relevant studies including a total of 1421 patients that examined 16 different intervention comparisons.Of the studies that compared buprenorphine to another drug, 11 studies performed comparative analyses between the randomised groups, and five studies found that buprenorphine was superior to the comparison treatment. Three studies found no differences between buprenorphine and the comparison drug, while another three studies found treatment with buprenorphine to be inferior to the alternative treatment in terms of the side effects profile or patients preference/acceptability.Of the studies that compared different doses or formulations/routes of administration of buprenorphine, pain intensity ratings did not differ significantly between intramuscular buprenorphine and buprenorphine suppository. However, the average severity of dizziness, nausea, vomiting and adverse events as a total were all significantly higher in the intramuscular group relatively to the suppository group (one study).Sublingual buprenorphine was associated with faster onset of pain relief compared to subdermal buprenorphine, with similar duration analgesia and no significant differences in adverse event rates reported between the treatments (one study).In terms of transdermal buprenorphine, two studies found it superior to placebo, whereas a third study found no difference between placebo and different doses of transdermal buprenorphine.The studies that examined different doses of transdermal buprenorphine did not report a clear dose-response relationship.The quality of this evidence base was limited by under-reporting of most bias assessment items (e.g., the patient selection items), by small sample sizes in several included studies, by attrition (with data missing from 8.2% of the enrolled/randomised patients for efficacy and from 14.6% for safety) and by limited or no reporting of the expected outcomes in a number of cases. The evidence for all the outcomes was very low quality.

AUTHORS' CONCLUSIONS

Based on the available evidence, it is difficult to say where buprenorphine fits in the treatment of cancer pain with strong opioids. However, it might be considered to rank as a fourth-line option compared to the more standard therapies of morphine, oxycodone and fentanyl, and even there it would only be suitable for some patients. However, palliative care patients are often heterogeneous and complex, so having a number of analgesics available that can be given differently increases patient and prescriber choice. In particular, the sublingual and injectable routes seemed to have a more definable analgesic effect, whereas the transdermal route studies left more questions.

Inhibitory effect of opiates on LPS mediated release of TNF and IL-8

Most patients with advanced cancer experience severe pain and are often treated with opiates. Cancer patients are especially susceptible to opportunistic infections due to treatment with immunosuppressive and cytostatic drugs. Since opiates have been demonstrated to have immunomodulatory effects, it is of clinical importance to evaluate potential differences between commonly used opiates with regard to their effect on the immune system. The aim of this study was to evaluate the effect of morphine, tramadol, fentanyl and ketobemidone on the functioning of the immune system with special reference to TNF and IL-8 release. Method. U-937 cells were preincubated with different concentrations of opioids followed by stimulation with LPS 100 μg/ml for three hours. The effect of opioids on the levels of cytokine mRNA was studied using RT-PCR. Erk and Akt phosphorylation was also measured by Western blot. Results. All opioids with the exception of fentanyl were capable of inhibiting TNF release from U-937 cells. Morphine had no effect on IL-8 release but the effect of other opiates was almost the same as the effect on TNF. All opioids with the exception of fentanyl were capable of inhibiting production of mRNA for TNF and IL-8. The observed effects of opiates were not always reversible by naloxone, suggesting that the effects might be mediated by other receptors or through a non-receptor mediated direct effect. Although preliminary evidence suggests the involvement of Erk and Akt pathways, further studies are needed to unravel the intracellular pathways involved in mediating the effects of opiates. Our data suggests that the order of potency with regard to inhibition of cytokine release is as follows: tramadol > ketobemidone > morphine > fentanyl. Conclusion. Further studies are needed to understand the clinical implications of the observed immunosuppressive effects of tramadol and ketobemidone and to improve opioid treatment strategies in patients with cancer.

[Taking care of drug addict in odontology]

In the dental surgery practice, a drug addicted patient declares suffering from high pain and asks with insistence to be examined in emergency. The clinical examination shows a pity overall dental status: an important dental deterioration, a periodontal disease. At the end of the examination, the patient suffering withdrawal syndrome, asks with a high demand up to physical threat, to get a prescription of psychotropic medicines, and especially opiates (high dose buprenorphine). In front of this situation, the dental surgeon will face two aspects: first of all, clinical issues, as taking care of the odontological pathologies, management of the pain and of the withdrawal syndrome and second of all, the legislation issues related to its responsibility of prescription writer and the specific attitude to adjust in front of a patient with withdrawal syndrome at the dental surgery practice.

Minor pathological changes are induced by naltrexone-poly(DL-lactide) implants in pregnant rats

Oral naltrexone is used to treat alcohol and heroin dependence but is associated with poor patient compliance. Sustained-release preparations have been developed to overcome noncompliance. Many sustained-release preparations are composed of polymers combined with naltrexone. Limited data indicate that polymers induce variable levels of tissue reactivity and that naltrexone may increase this effect. A slow-release subcutaneous naltrexone-poly (DL-lactide) implant is currently being trialed to treat heroin dependence in Western Australia. A minority of women fall pregnant and, although tissue reactivity in nonpregnant humans is relatively minor, detailed chronological data during pregnancy are lacking. Histological changes in pregnant rats were assessed; a single active tablet containing poly[trans-3,6-dimethyl-1,4-dioxyane-2,5-dione] (DL-lactide) loaded with 25 mg of naltrexone was implanted subcutaneously, and tissue response was compared with inactive polymer implantation. Rats were timed mated at 13-26 days postimplant. Tissue assessment up to 75 days by a pathologist showed that naltrexone induced chronic inflammatory response in a dose-dependent manner, although still at a low level. Furthermore, for inactive implants, minimal foreign body reaction and fibrosis, together with low-level inflammation, suggested good long-term biocompatibility. We conclude that the Australian naltrexone-poly(DL-lactide) implant is tolerated in pregnant rats, reinforcing its potential role for managing alcohol and heroin dependence in pregnant humans.

Pain management: is opioid immunosuppression a clinical problem?

For more than 100 years, the use of opioid analgesic agents has been linked with modulation of the immune system in man. More recently, it has become apparent that both exogenous and endogenous opioids exert some effect upon the immune system but that this can be beneficial or deleterious depending on numerous variables. Of the strong opioid analgesics in current use, the majority are seen to cause immunosuppression in man. However, it still remains unclear whether this is clinically important in man although it would appear to be good practice to avoid such agents in patients already immunosuppressed by disease or pharmacotherapy. Powerful opioid analgesics without immunosuppressive properties can be selected and should be used in such situations and as these agents can offer additional benefits in addition to their non-immunosuppresive analgesia, it should be considered whether to use them at all times in preference to immunosuppressive opioids.

Opioids and the immune system

Opioid compounds such as morphine produce powerful analgesia that is effective in treating various types of pain. In addition to their therapeutic efficacy, opioids can produce several well known adverse events, and, as has recently been recognized, can interfere with the immune response. The immunomodulatory activities of morphine have been characterized in animal and human studies. Morphine can decrease the effectiveness of several functions of both natural and adaptive immunity, and significantly reduces cellular immunity. Indeed, in animal studies morphine is consistently associated with increased morbidity and mortality due to infection and worsening of cancer. However, from several animal studies it emerges that not all opioids induce the same immunosuppressive effects, and evaluating each opioid's profile is important for appropriate analgesic selection. Buprenorphine is a potent opioid that is frequently prescribed for chronic pain. Acute intracerebroventricular administration of buprenorphine has been shown in rats not to affect cellular immune responses, while a statistically significant inhibition of the immune response was observed with morphine. In mouse studies, chronic administration of buprenorphine led to immune parameters important for antimicrobial responses or for anti-tumour surveillance (lymphoproliferation, natural killer (NK)-lymphocyte activity, cytokine production, lymphocyte number) being unaffected. In contrast, levels of these immune markers were significantly reduced when the potent micro-agonist fentanyl was administered, but recovered after longer periods as tolerance developed. Because the intrinsic immunosuppressive activity varies between individual opioids, predicting the outcome on immunity can be difficult. To study this, the effects of morphine, fentanyl and buprenorphine on NK-lymphocyte activity depressed by experimental surgery were examined in rats. Treating animals immediately after surgery with equianalgesic doses of morphine and buprenorphine significantly reduced surgery-induced immunosuppression. However, buprenorphine reverted NK-lymphocyte activity to preoperative levels, while in morphine-treated rats NK-lymphocyte activity was ameliorated, although not completely. In contrast, fentanyl did not prevent immunosuppression induced by surgery. Overall, from several animal studies it emerges that buprenorphine has the more favourable profile, being a potent analgesic devoid of intrinsic immunosuppressive activity.