Immunosuppressive effects of opioids--clinical relevance

The Impact of Nonpharmacological Interventions on Opioid Use for Chronic Noncancer Pain: A Scoping Review

Despite the lack of evidence, opioids are still routinely used as a solution to long-term management for chronic noncancer pain (CNCP). Given the significant risks associated with long-term opioid use, including the increased number of unregulated opioid pills at large in the opioid ecosystem, opioid cessation or reduction may be the desired goal of the patient and clinician. Viable nonpharmacological interventions (NPIs) to complement and/or replace opioids for CNCP are needed. Comprehensive reviews that address the impact of NPIs to help adults with CNCP reduce opioid use safely are lacking. We conducted a literature search in PubMed, CINAHL, Embase, PsycINFO, and Scopus for studies published in English. The initial search was conducted in April 2021, and updated in January 2024. The literature search yielded 19,190 relevant articles. Thirty-nine studies met the eligibility criteria and underwent data extraction. Of these, nineteen (49%) were randomized controlled trials, eighteen (46%) were observational studies, and two (5%) were secondary analyses. Among adults with CNCP who use opioids for pain management, studies on mindfulness, yoga, educational programs, certain devices or digital technology, chiropractic, and combination NPIs suggest that they might be an effective approach for reducing both pain intensity and opioid use, but other NPIs did not show a significant effect (e.g., hypnosis, virtual reality). This review revealed there is a small to moderate body of literature demonstrating that some NPIs might be an effective and safe approach for reducing pain and opioid use, concurrently.

The effect of acellular scaffold loaded with Wharton's jelly-derived stem cells and mineral pitch on healing of burn model in rat

Severe burns often result in an exacerbated inflammatory response, which can contribute to further injury. This inflammatory response may lead to an increased risk of infection, multiple organ failure, and death. This study aimed to investigate the potential of reducing inflammation to enhance burn wound healing in rats using ovine's small intestinal submucosa as a carrier for Wharton's jelly mesenchymal stem cells (WJ-MSCs) and Mineral Pitch (MP). A rat burn model was developed, and the animals were divided into four groups: control group: burn, placebo group: scaffold-treated burn, cell experimental group: WJ-MSCs seeded scaffold-treated burn, and cell and MP experimental group: scaffolds loaded with WJ-MSCs and MP-treated burn. After treating the wounds in the relevant groups and sampling them on days 5, 14 and 21, histological and pathological parameters, and the expression of genes involved in angiogenesis and epithelialization were evaluated. The study results revealed several findings in the burn wounds. These included changes in mast cell populations, a decrease in inflammatory neutrophils and lymphocytes, an increase in fibroblasts and blood vessels, and upregulation of angiogenesis and epithelialization genes. These changes collectively contributed to enhanced wound healing in cell and MP experimental group compared to the other groups. The findings suggest that scaffolds loaded with Wharton's jelly-derived stem cells and MP can serve as engineered tools to modulate inflammatory conditions during the burn wound healing process. These interventions can improve burn wound management and promote better outcomes.

Opioid-sparing effects of ultrasound-guided erector spinae plane block for video-assisted thoracoscopic surgery: a randomized controlled study

BACKGROUND

The erector spinae plane block (ESPB) is a new analgesic method used in thoracic surgery. However, few studies have characterized their effects on perioperative opioid consumption. We aimed to evaluate the effects of ESPB on perioperative opioid consumption in patients who underwent video-assisted thoracoscopic surgery (VATS).

METHODS

This was a randomized, observer-blinded clinical trial at a single-centre academic hospital. Eighty patients were scheduled for thoracoscopic segmentectomy or lobectomy by VATS for lung cancer. Forty participants were randomly assigned to ESPB or control group. All patients received intravenous patient-controlled postoperative analgesia. Perioperative opioid consumption, visual analogue scale (VAS) scores, and adverse events were recorded.

RESULTS

Intraoperative and postoperative opioid consumption and static/dynamic VAS scores were significantly lower in the early hours after VATS in the ESPB group (p < 0.05) than the control group. No significant differences were observed in adverse effects between the two groups.

CONCLUSIONS

ESPB reduced intraoperative opioid consumption and early postoperative pain in patients undergoing VATS. Our findings support the view that ESPB is a safe and highly effective option for regional analgesia for VATS.

TRIAL REGISTRATION

http://www.chictr.org.cn , ChiCTR1800019335.

Association of substance-use disorder with outcomes of major elective abdominal operations: A contemporary national analysis

Background

Affecting >20million people in the U.S., including 4 % of all hospitalized patients, substance use disorder (SUD) represents a growing public health crisis. Evaluating a national cohort, we aimed to characterize the association of concurrent SUD with perioperative outcomes and resource utilization following elective abdominal operations.

Methods

All adult hospitalizations entailing elective colectomy, gastrectomy, esophagectomy, hepatectomy, and pancreatectomy were tabulated from the 2016-2020 National Inpatient Sample. Patients with concurrent substance use disorder, comprising alcohol, opioid, marijuana, sedative, cocaine, inhalant, hallucinogen, or other psychoactive/stimulant use, were considered the SUD cohort (others: nSUD). Multivariable regression models were constructed to evaluate the independent association between SUD and key outcomes.

Results

Of ∼1,088,145 patients, 32,865 (3.0 %) comprised the SUD cohort. On average, SUD patients were younger, more commonly male, of lowest quartile income, and of Black race. SUD patients less frequently underwent colectomy, but more often pancreatectomy, relative to nSUD.Following risk adjustment and with nSUD as reference, SUD demonstrated similar likelihood of in-hospital mortality, but remained associated with increased odds of any perioperative complication (Adjusted Odds Ratio [AOR] 1.17, CI 1.09-1.25). Further, SUD was linked with incremental increases in adjusted length of stay (β + 0.90 days, CI +0.68-1.12) and costs (β + $3630, CI +2650-4610), as well as greater likelihood of non-home discharge (AOR 1.54, CI 1.40-1.70).

Conclusions

Concurrent substance use disorder was associated with increased complications, resource utilization, and non-home discharge following major elective abdominal operations. Novel interventions are warranted to address increased risk among this vulnerable population and address significant disparities in postoperative outcomes.

Causal effects and immune cell mediators between prescription analgesic use and risk of infectious diseases: a Mendelian randomization study

Introduction

Clinical observations have found that prolonged use of analgesics increases the incidence of infection. However, the direct causal relationship between prescription analgesic use (PAU) and risk of infection (ROI) remains unclear.

Methods

This study used Mendelian randomization (MR) design to estimate the causal effect of PAU on ROI, as well as their mediating factors. Genetic data on prescription analgesics use and immune cells were obtained from published GWAS. Additionally, data on ROI were extracted from the FinnGen database. Two-sample MR analysis and multivariate MR (MVMR) analysis were performed using inverse variance weighting (IVW) to ascertain the causal association between PAU and ROI. Finally, 731 immune cell phenotypes were analyzed for their mediating role between analgesics and infection.

Results

Using two-sample MR, IVW modeling showed that genetically predicted opioid use was associated with increased risk of pulmonary infection (PI) (OR = 1.13, 95% CI: 1.05-1.21, p< 0.001) and upper respiratory infection (URI) (OR = 1.18, 95% CI: 1.08-1.30, p< 0.001); non-steroidal anti-inflammatory drugs (NSAIDs) were related to increased risk of skin and subcutaneous tissue infection (OR = 1.21, 95% CI: 1.05-1.39, p = 0.007), and antimigraine preparations were linked to a reduced risk of virus hepatitis (OR = 0.79, 95% CI: 0.69-0.91, p< 0.001). In MVMR, the association of opioids with URI and PI remained after accounting for cancer conditions. Even with a stricter threshold (p< 0.05/30), we found a significant causal association between opioids and respiratory infections (URI/PI). Finally, mediation analyses found that analgesics influence the ROI through different phenotypes of immune cells as mediators.

Conclusion

This MR study provides new genetic evidence for the causal relationship between PAU and ROI, and the mediating role of immune cells was demonstrated.

Role of neurotransmitters in immune-mediated inflammatory disorders: a crosstalk between the nervous and immune systems

Immune-mediated inflammatory diseases (IMIDs) are a group of common heterogeneous disorders, characterized by an alteration of cellular homeostasis. Primarily, it has been shown that the release and diffusion of neurotransmitters from nervous tissue could result in signaling through lymphocyte cell-surface receptors and the modulation of immune function. This finding led to the idea that the neurotransmitters could serve as immunomodulators. It is now manifested that neurotransmitters can also be released from leukocytes and act as autocrine or paracrine modulators. Increasing data indicate that there is a crosstalk between inflammation and alterations in neurotransmission. The primary goal of this review is to demonstrate how these two pathways may converge at the level of the neuron and glia to involve in IMID. We review the role of neurotransmitters in IMID. The different effects that these compounds exert on a variety of immune cells are also reviewed. Current and future developments in understanding the cross-talk between the immune and nervous systems will undoubtedly identify new ways for treating immune-mediated diseases utilizing agonists or antagonists of neurotransmitter receptors.

Opioid Receptor Expression in Colorectal Cancer: A Nested Matched Case-Control Study

Background

There is growing interest in the possible effect of perioperative anesthetic management on the growth and spread of cancer. The impact of perioperative use of opioids on cancer recurrence remains controversial and an assessment cannot yet be established based on current publications. This study aimed to assess the differential expression of opioid receptors between healthy and tumor tissues in patients with stage II and III colorectal cancer undergoing elective surgery by immunohistochemistry (IHC).

Methods

Propensity-score matched case-control study nested in a retrospective cohort of patients with stage II or III colorectal. The primary endpoint was the difference in µ-opioid receptor (MOR) expression measured by IHC between tumor and healthy tissue in subject with or without recurrence. Secondary endpoints were to evaluate the differences in Opioid Growth Factor Receptor (OGFR), cyclic adenosine monophosphate (cAMP) production and protein kinase A (PKA) in the matched sample and from a from samples of colorectal cancer stored in the Cancer Genome Atlas (TCGA) and Genotype Tissue Expression Project (GTEx).

Results

There was a significant difference in MOR receptor (median 3 [intequartile range IQR: 1-3] and 0 [IQR: 0-2], P<0.001) and OGFR receptor (median 6 [IQR: 5-6] and 2 [IQR: 1-2], P<0.001) in tumor and control tissue respectively. However, there were no significant differences in cAMP nor PKA expression between both types of tissues and in expression in any of the analyzed variables by recurrence status. The MOR and OGFR expression data from TCGA database were similar to our sample size data with lower expression of MOR and higher expression of OGFR in tumoural samples with a skewed distribution for MOR expression in tumor tissue both in patients with and without recurrence.

Conclusion

In patients with stage II and III colorectal cancer, overall expression of MOR and OGFR was significantly increased but was not different between previously matched patients with or without recurrence. No differences were found in the analyzed metabolic pathway of cAMP-PKA: These results were confirmed by an in silico analysis of samples from the TCGA-GTEx database.

Preoperative Opioid Use Is Associated With Higher Revision Rates in Total Joint Arthroplasty: A Systematic Review

BACKGROUND

Although preoperative opioid use has been associated with poor postoperative patient-reported outcome measures and delayed return to work in patients undergoing total joint arthroplasty, direct surgery-related complications in patients on chronic opioids are still not clear. Thus, we sought to perform a systematic review of the literature to evaluate the influence of preoperative opioid use on postoperative complications and revision following primary total joint arthroplasty.

METHODS

Following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, we queried PubMed, EMBASE, the Cochrane Library, and the ISI Web of Science for studies investigating the influence of preoperative opioid use on postoperative complications following total hip arthroplasty and total knee arthroplasty up to May 2020.

RESULTS

After applying exclusion criteria, 10 studies were included in the analysis which represented 87,165 opioid users (OU) and 5,214,010 nonopioid users (NOU). The overall revision rate in the OU group was 4.79% (3846 of 80,303 patients) compared to 1.21% in the NOU group (43,719 of 3,613,211 patients). There was a higher risk of aseptic loosening (odds ratio [OR] 1.30, 95% confidence interval [CI] 1.11-1.53, P = .002), periprosthetic fractures (OR 1.89, 95% CI 1.53-2.34, P < .00001), and dislocations (OR 1.26, 95% CI 1.14-1.39, P < .00001) in the OU group compared to the NOU group. Overall, 5 of 6 studies reporting on periprosthetic joint infection (PJI) rates showed statistically significant correlation between preoperative opioid use and higher PJI rates.

CONCLUSION

There is strong evidence that preoperative opioid use is associated with a higher overall revision rate for aseptic loosening, periprosthetic fractures, and dislocation, and an increased risk for PJI.

LEVEL OF EVIDENCE

Level III, systematic review.

Factors Affecting Changes of Cluster of Differentiation 4 Cell Counts Among Human Immunodeficiency Virus-positive People Who Inject Heroin and Receive Methadone Maintenance Treatment

AIMS

Opioids have been hypothesized to suppress the immune function and worsen outcomes among people living with human immunodeficiency virus (HIV). The study aimed to identify key factors associated with the increased cluster of differentiation 4 (CD4) cell counts among HIV-positive people who inject heroin and receive methadone maintenance treatment (MMT).

METHODS

This longitudinal study was conducted at a psychiatric hospital in Northern Taiwan. Participants were recruited from 2006 through 2011, and received CD4 cell counts and HIV viral load monitoring once every 4 to 6 months. Trend in CD4 cell counts, defined as change in CD4 cell count over time, was used as the outcome measure. Independent variables included MMT-related factors and baseline characteristics. Baseline characteristics included age, gender, CD4 cell count, HIV viral load, tests for other infections, liver function tests, and urine drug screens.

RESULTS

Three hundred and fifty one participants were recruited during the study period. The multivariate linear mixed model analysis revealed a higher MMT attendance rate, a higher baseline CD4 cell count, and a shorter duration of MMT were associated with an increase in CD4 cell count over time.

CONCLUSIONS

The study showed better adherence to MMT was associated with better preserved immune functions. The negative impact of duration of MMT on CD4 cell counts may be ameliorated by improving the attendance rate, initiation of MMT earlier when the baseline CD4 cell count is still relatively high and by the other beneficial effects of MMT, such as healthier lifestyles with reduced use of short-acting opioids.

Substance use and related harms in the context of COVID-19: a conceptual model

As the effects of COVID-19 have been unfolding, growing attention has been paid to the intersection of COVID-19 and substance use and the related harms. However, there are few theories and little empirical evidence to guide investigations in this area. To advance this emerging area of inquiry, we present a conceptual model that synthesizes evidence, information and knowledge on substance use and related harms in the context of the pandemic. The conceptual model offers a visual representation of the connections between the pandemic and substance use and related harms, and can be used to identify areas for future research.

Neuromodulation With Burst and Tonic Stimulation Decreases Opioid Consumption: A Post Hoc Analysis of the Success Using Neuromodulation With BURST (SUNBURST) Randomized Controlled Trial

OBJECTIVE

The SUNBURST study was a prospective, multicenter, randomized crossover trial of a single device delivering burst and tonic spinal cord stimulation (SCS) for chronic trunk and/or limb pain. We performed a post hoc analysis of opioid consumption at baseline and after device implantation.

MATERIALS AND METHODS

After implantation, 100 patients were randomized to one mode (tonic or burst) for 12 weeks, and the other mode for the subsequent 12 weeks. After the crossover period (24 weeks), patients chose their preferred mode and were assessed for one year. We analyzed 69 patients who took opioid medication at baseline. The primary endpoint was opioid consumption in morphine milligram equivalents (MMEs) at baseline and 12 months postimplantation. Subgroup analysis included opioid consumption based on Center for Disease Control markers (<50, 50-90, 90-120, >120 MME/day) and stimulation mode preference.

RESULTS

Opioid consumption at 12 months was lower compared to baseline (53.94 vs. 79.19 MME, MD -25.25, 95% CI -43.77 to 6.73, p = 0.008). By 12 months, 11 of 69 patients (15.9%) discontinued all opioid (p = 0.001). Based on CDC dose markers, the proportion of patients taking >120 MME/day decreased by 61.7% at 12 months postintervention compared to baseline (p = 0.043). Forty-five of 69 patients (65.2%) preferred burst SCS while 15 of 69 patients (21.7%) preferred tonic SCS (p < 0.001).

CONCLUSION

A device delivering tonic and burst SCS was associated with decreased opioid consumption after 12 months in patients with chronic trunk and/or limb pain. The proportion of patients reporting the highest opioid intake (>120 MME/day) decreased to a lower CDC dose category by 61.7%, carrying important implications for those at highest risk for opioid-related substance use disorder, overdose, and death.

Effects of ultrasound-guided paravertebral block on MMP-9 and postoperative pain in patients undergoing VATS lobectomy: a randomized, controlled clinical trial

Background

Local anesthesia can reduce the response to surgical stress and decrease the consumption of opioids, which may reduce immunosuppression and potentially delay postoperative tumor recurrence. We compared paravertebral block (PVB) combined with general anesthesia (GA) and general anesthesia regarding their effects on postoperative pain and matrix metalloproteinase-9 (MMP-9) after video-assisted thoracoscopic surgery (VATS) lobectomy.

Methods

54 patients undergoing elective VATS lobectomy at a single tertiary care, teaching hospital located in Qingdao between May 2, 2018 and Sep 28, 2018 were randomised by computer to either paravertebral block combined with general anesthesia or general anesthesia. The primary outcomes were pain scores at rest and on cough at 1, 4, 24, and 48 h after surgery. The secondary outcome were plasma concentrations of MMP-9, complications, and length of postoperative hospital stay.

Results

75 were enrolled to the study, of whom 21 were excluded before surgery. We analyzed lobectomy patients undergoing paravertebral block combined with general anesthesia (n = 25) or general anesthesia (n = 24). Both groups were similar regarding baseline characteristics. Pain scores at rest at 4 h and 24 h, on cough at 4 h were lower in PVB/GA group, compared with GA group (P < 0.05). There were no difference in pain scores at rest at 1 h, 48 h and on cough at 1 h, 24 h, and 48 h between groups. Patients in the PVB/GA group showed a greater decrease in plasma MMP-9 level at T1 and T2 after VATS lobectomy (P < 0.05). Postoperative complications and length of stay did not differ by anesthetic technique.

Conclusions

The paravertebral block/general anesthesia can provide statistically better pain relief and attenuate MMP-9 response to surgery and after VATS lobectomy. This technique may be beneficial for patients to recover rapidly after lung surgery and reduce postoperative tumor recurrence.

Trial registration

Chinese Clinical Trial registration number ChiCTR1800016379. Registered 28 May 2018.

Morphine Withdrawal Enhances HIV Infection of Macrophages

Opioid withdrawal recurs at high rates in opioid use disorder and compromises the immune system. In general, there are two types of opioid withdrawal: abrupt withdrawal (AW) and precipitated withdrawal (PW). In this study, we examined the effect of morphine AW or morphine PW on HIV infection of human blood monocyte-derived macrophages. We observed that both morphine AW and PW enhanced the susceptibility of macrophages to HIV infection. In addition, both AW and PW activated HIV replication in the latently infected myeloid cells (U1 and OM10.1). Investigation of mechanisms responsible for these observations showed that both AW and PW could inhibit the expression of multiple intracellular HIV inhibitory factors, including APOBE3G/F, SAMHD1, MX2, and HIV restriction microRNAs (miR-28, miR-125b, and miR-150) in macrophages. These findings provide additional evidence to support the notion that opioid use compromises the intracellular anti-HIV immunity and facilitates HIV infection and persistence in macrophages.

Opioid free onco-anesthesia: Is it time to convict opioids? A systematic review of literature

The epidemic of opioid crisis started getting recognised as a public health emergency in view of increasing opioid-related deaths occurring due to undetected respiratory depression. Prescribing opioids at discharge has become an independent risk factor for chronic opioid use, following which, prescription practices have undergone a radical change. A call to action has been voiced recently to end the opioid epidemic although with the pain practitioners still struggling to make opioids readily available. American Society of Anesthesiologist (ASA) has called for reducing patient exposure to opioids in the surgical setting. Opioid sparing strategies have emerged embracing loco-regional techniques and non-opioid based multimodal pain management whereas opioid free anesthesia is the combination of various opioid sparing strategies culminating in complete elimination of opioid usage. The movement away from opioid usage perioperatively is a massive but necessary shift in anesthesia which has rationalised perioperative opioid usage. Ideal way moving forward would be to adapt selective low opioid effective dosing which is both procedure and patient specific while reserving it as rescue analgesia, postoperatively. Many unknowns persist in the domain of immunologic effects of opioids, as complex interplay of factors gets associated during real time surgery towards outcome. At present it would be too premature to conclude upon opioid-induced immunosuppression from the existing evidence. Till evidence is established, there are no recommendations to change current clinical practice. At the same time, consideration for multimodal opioid sparing strategies should be initiated in each patient undergoing surgery.

The role of regional anesthesia in the propagation of cancer: A comprehensive review

New cancer incidences worldwide will eclipse 18 million in 2019, with nearly 10 million cancer-related deaths. It is estimated that in the United States, almost 40% of individuals will be diagnosed with cancer in their lifetime. Surgical resection of primary tumors remains a cornerstone of cancer treatment; however, the surgical process can trigger an immune-suppressing sympathetic response, which promotes tumor growth of any residual cancerous cells post surgery. Regional and local anesthesia have become staples of anesthesia and analgesia during and after surgery. Recently, much evidence in the form of retrospective and prospective studies has come to light regarding the protective, antitumor properties of anesthetic and analgesic agents across a wide variety of cancers and patient demographics. It is believed that by blocking afferent pain signals, the body does not mount the sympathetic response that contributes to the perpetuation of disease after surgical treatment. This review, therefore, investigates these studies as they pertain to the treatment and outcomes of cancers treated surgically to elucidate the role of regional anesthesia in the propagation of cancer.

Long-acting Opioid Use and the Risk of Serious Infections: A Retrospective Cohort Study

BACKGROUND

Although evidence from animal and human studies indicates opioid analgesics increase susceptibility to infections, it is unclear whether the risk varies by specific opioid. We compared the risk of serious infection among patients initiating long-acting opioid analgesics with and without previously reported immunosuppressive properties.

METHODS

We conducted a retrospective cohort study of Tennessee Medicaid enrollees age ≥18 years initiating long-acting opioids (1995-2015). Hospitalizations for serious infection were identified using validated coding algorithms. We used multivariable Poisson regression models to calculate adjusted incidence rate ratios (aIRR) and 95% confidence intervals (CI) to compare the infection risk among patients using long-acting opioids with known immunosuppressive properties (morphine, fentanyl, methadone) to the infection risk among patients using long-acting opioids without known immunosuppressive properties (oxycodone, oxymorphone, tramadol) accounting for demographics, opioid dose, comorbidities and pain conditions, medication use, frailty indicators, and healthcare encounter history using exposure propensity scores. We further compared users of individual long-acting opioids to long-acting morphine users (considered the prototypical immunosuppressive opioid).

RESULTS

Among the 61 240 patients initiating opioids with immunosuppressive properties and 22 811 patients initiating opioids without immunosuppressive properties, we identified 1906 serious infections. Nonimmunosuppressive opioid users had a lower rate of infections than immunosuppressive opioid users (aIRR:0.78 [CI: 0.66-0.91]). Among individual opioids, oxycodone users had a lower rate of infection than morphine users (aIRR:0.73 [CI: 0.60-0.89]). There were no significant differences in the infection risk between other opioids and morphine.

CONCLUSION

The risk of serious infections among long-acting opioid users varies by opioid type. Providers should carefully consider the risk of serious infections when making pain management decisions.

Interaction of neurotransmitters and neurochemicals with lymphocytes

Neurotransmitters and neurochemicals can act on lymphocytes by binding to receptors expressed by lymphocytes. This review describes lymphocyte expression of receptors for a selection of neurotransmitters and neurochemicals, the anatomical locations where lymphocytes can interact with neurotransmitters, and the effects of the neurotransmitters on lymphocyte function. Implications for health and disease are also discussed.

Opioids in the immune system: from experimental studies to clinical practice

INTRODUCTION

Opioids interact with both innate and adaptive immune systems and have direct effects on opioid receptors located on immune cells. Research on this topic has provided evidence of the opioid influence on the immune response associated with surgical stress. The immunological effects of opioids are currently being investigated, particularly whether they influence the outcome of surgery or the underlying disease regarding important aspects like infection or cancer progression. This review addresses background research related to the influence of the opioid receptor on the immune system, the immunosuppressive effect associated with major opioids during the perioperative period, and their clinical relevance. The objective of the study was to review the effects of opioids on the immune system.

Chronic opioid use and clinical outcomes in lung transplant recipients: A single-center cohort study

INTRODUCTION

Chronic opioid use is common after organ transplantation, and has been associated with poor outcomes in transplantation of abdominal organs. However, little is known about possible influences of chronic opioid use on outcomes of lung transplantation (LTx).

OBJECTIVES

We assessed whether long-term chronic opioid use influenced clinical outcomes among LTx recipients at our program.

METHODS

We retrospectively evaluated chronic opioid use among bilateral LTx recipients ages 12 and older followed at our institution 1-5 years post-transplant. Chronic opioid use was defined as ≥3 months of consecutive prescribed use. Outcomes included survival, hospitalization, emergency department and urgent care visits, forced expiratory volume in one second (FEV1), and allograft rejection.

RESULTS

Twenty-one patients ages 15-50 years met inclusion criteria. On multivariable analysis, initiation of chronic opioid use was followed by increased mortality hazard (hazard ratio=7.1; 95% confidence interval [CI]: 1.1, 45.0, P = 0.037) and decreased FEV1 (-16%; 95% CI: -24%, -7%; P < 0.001), although no differences were observed in risk of acute care visits, inpatient admission, or chronic rejection.

CONCLUSION

This analysis presents the first evidence that late-onset chronic opioid use may be associated with decreased lung function and increased mortality after LTx. Therefore, evaluation of chronic opioid use should be included in the routine monitoring of transplant recipients, to better define the impact of this risk factor on LTx outcomes.

Preoperative Opioids Increase the Risk of Periprosthetic Joint Infection After Total Joint Arthroplasty

BACKGROUND

Opioids have well-known immunosuppressive properties and preoperative opioid consumption is relatively common among patients undergoing total joint arthroplasty (TJA). The hypothesis of this study was that utilization of opioids preoperatively would increase the incidence of subsequent periprosthetic joint infection (PJI) in patients undergoing primary TJA.

METHODS

A comparative cohort study design was set up that used a cohort of 23,754 TJA patients at a single institution. Patient records were reviewed to extract relevant information, in particular details of opioid consumption, and an internal institutional database of PJI was cross-referenced against the cohort to identify patients who developed a PJI within 2 years of index arthroplasty. Univariate and multivariate linear regression analyses were used to examine the potential association between preoperative opioid consumption and the development of PJI.

RESULTS

Among the total cohort of 23,754 patients, 5051 (21.3%) patients used opioids before index arthroplasty. Preoperative opioid usage overall was found to be a significant risk factor for development of PJI in the univariate (odds ratio, 1.63; P = .005) and multivariate analyses (adjusted odds ratio, 1.53 [95% confidence interval, 1.14-2.05], P = .005).

CONCLUSION

Preoperative opioid consumption is independently associated with a higher risk of developing a PJI after primary TJA. These findings underscore a need for caution when prescribing opioids in patients with degenerative joint disease who may later require arthroplasty.

Immune function after major surgical interventions: the effect of postoperative pain treatment

INTRODUCTION

Impaired immune function during the perioperative period may be associated with worse short- and long-term outcomes. Morphine is considered a major contributor to immune modulation.

PATIENTS AND METHODS

We performed a pilot study to investigate postoperative immune function by analyzing peripheral blood mononuclear cells' functionality and cytokine production in 16 patients undergoing major abdominal surgery. All patients were treated with intravenous (i.v.) patient-controlled analgesia with morphine and continuous wound infusion with ropivacaine+methylprednisolone for 24 hours. After 24 hours, patients were randomized into two groups, one continuing intrawound infusion and the other receiving only i.v. analgesia. We evaluated lymphoproliferation and cytokine production by peripheral blood mononuclear cells at the end of surgery and at 24 and 48 hours postoperatively.

RESULTS

A significant reduction in TNF-α, IL-2, IFN-γ and lymphoproliferation was observed immediately after surgery, indicating impaired cell-mediated immunity. TNF-α and IFN-γ remained suppressed up to 48 hours after surgery, while a trend to normalization was observed for IL-2 and lymphoproliferation, irrespective of the treatment group. A significant inverse correlation was present between age and morphine and between age and lymphoproliferation. No negative correlation was present between morphine and cytokine production. We did not find any differences within the two groups between 24 and 48 hours in terms of morphine consumption and immune responses.

CONCLUSION

A relevant depression of cell-mediated immunity is associated with major surgery and persists despite optimal analgesia. Even though morphine may participate in immunosuppression, we did not retrieve any dose-related effect.

Immunomodulatory Role of Complement Proteins in the Neuropathology Associated with Opiate Abuse and HIV-1 Co-Morbidity

The complement system which is a critical mediator of innate immunity plays diverse roles in the neuropathogenesis of HIV-1 infection such as clearing HIV-1 and promoting productive HIV-1 replication. In the development of HIV-1 associated neurological disorders (HAND), there may be an imbalance between complement activation and regulation, which may contribute to the neuronal damage as a consequence of HIV-1 infection. It is well recognized that opiate abuse exacerbates HIV-1 neuropathology, however, little is known about the role of complement proteins in opiate induced neuromodulation, specifically in the presence of co-morbidity such as HIV-1 infection. Complement levels are significantly increased in the HIV-1-infected brain, thus HIV-induced complement synthesis may represent an important mechanism for the pathogenesis of AIDS in the brain, but remains underexplored. Anti-HIV-1 antibodies are able to initiate complement activation in HIV-1 infected CNS cells such as microglia and astrocytes during the course of disease progression; however, this complement activation fails to clear and eradicate HIV-1 from infected cells. In addition, the antiretroviral agents used for HIV therapy cause dysregulation of lipid metabolism, endothelial, and adipocyte cell function, and activation of pro-inflammatory cytokines. We speculate that both HIV-1 and opiates trigger a cytokine-mediated pro-inflammatory stimulus that modulates the complement cascade to exacerbate the virus-induced neurological damage. We examined the expression levels of C1q, SC5b-9, C5L2, C5aR, C3aR, and C9 key members of the complement cascade both in vivo in post mortem brain frontal cortex tissue from patients with HAND who used/did not use heroin, and in vitro using human microglial cultures treated with HIV tat and/or heroin. We observed significant expression of C1q and SC5b-9 by immunofluorescence staining in both the brain cortical and hippocampal region in HAND patients who abused heroin. Additionally, we observed increased gene expression of C5aR, C3aR, and C9 in the brain tissue of both HIV-1 infected patients with HAND who abused and did not abuse heroin, as compared to HIV negative controls. Our results show a significant increase in the expression of complement proteins C9, C5L2, C5aR, and C3aR in HIV transfected microglia and an additional increase in the levels of these complement proteins in heroin-treated HIV transfected microglia. This study highlights the a) potential roles of complement proteins in the pathogenesis of HIV-1-related neurodegenerative disorders; b) the combined effect of an opiate, like heroin, and HIV viral protein like HIV tat on complement proteins in normal human microglial cells and HIV transfected microglial cells. In the context of HAND, targeting selective steps in the complement cascade could help ameliorating the HIV burden in the CNS, thus investigations of complement-related therapeutic approaches for the treatment of HAND are warranted.

Risk factors for cardiopulmonary and respiratory arrest in medical and surgical hospital patients on opioid analgesics and sedatives

BACKGROUND

Opioid induced respiratory depression is a known cause of preventable death in hospitals. Medications with sedative properties additionally potentiate opioid-induced respiratory and sedative effects, thereby elevating the risk for adverse events. The goal of this study was to determine what specific factors increase the risk of in-hospital cardiopulmonary and respiratory arrest (CPRA) in medical and surgical patients on opioid and sedative therapy.

METHODS

The present study analyzed 14,504,809 medical inpatient and 6,771,882 surgical inpatient discharges reported into the Premier database from 2008 to 2012. Patients were divided in four categories: on opioids; on sedatives; on both opioids and sedatives; and on neither opioids nor sedatives.

RESULTS

During hospital admission, 57% of all medical patients and 90% of all surgical patients were prescribed opioids, sedatives, or both. Surgical patients had a higher incidence of CPRA than medical patients (6.17 vs. 3.77 events per 1000 admissions; Relative Risk: 1.64 [95%CI: 1.62-1.66; p<0.0001). Opioids and sedatives were found to be independent predictors of CPRA (adjusted OR of 2.24 [95%CI: 2.18-2.29] for opioids and adjusted OR 1.80 [95%CI: 1.75-1.85] for sedatives in medical patients, and adjusted OR of 1.12 [95%CI: 1.07-1.16] for opioids and adjusted OR of 1.58 [95%CI: 1.51-1.66] for sedatives in surgical patients), with the highest risk in groups who received both types of medications (adjusted OR of 3.83 [95% CI: 3.74-3.92] in medical patients, and adjusted OR of 2.34 [95% CI: 2.25-2.42] in surgical patients) compared with groups that received neither type of medication. The common risk factors of CPRA in medical and surgical patients receiving both opioids and sedatives were Hispanic origin, mild liver disease, obesity, and COPD. Additionally, medical and surgical groups had their own unique risk factors for CPRA when placed on opioid and sedative therapy.

CONCLUSIONS

Opioids and sedatives are independent and additive predictors of CPRA in both medical and surgical patients. Receiving both classes of medications further exacerbates the risk of CPRA for these patients. By identifying groups at risk among medical and surgical in-hospital patients, this study provides a step towards improving our understanding of how to use opioid and sedative medications safely, which may influence our treatment strategies and outcomes. More precise monitoring of selected high-risk patients may help prevent catastrophic cardiorespiratory complications from these medications. As a retrospective administrative database analysis, this study does not establish the causality or the temporality of the events but rather draws statistically significant associations between the clinical factors and outcomes.

Glutamate dependent NMDA receptor 2D is a novel angiogenic tumour endothelial marker in colorectal cancer

Current vascular-targeted therapies in colorectal cancer (CRC) have shown limited benefit. The lack of novel, specific treatment in CRC has been hampered by a dearth of specific endothelial markers. Microarray comparison of endothelial gene expression in patient-matched CRC and normal colon identified a panel of putative colorectal tumour endothelial markers. Of these the glutamate dependent NMDA receptor GRIN2D emerged as the most interesting target. GRIN2D expression was shown to be specific to colorectal cancer vessels by RTqPCR and IHC analysis. Its expression was additionally shown be predictive of improved survival in CRC. Targeted knockdown studies in vitro demonstrated a role for GRIN2D in endothelial function and angiogenesis. This effect was also shown in vivo as vaccination against the extracellular region of GRIN2D resulted in reduced vascularisation in the subcutaneous sponge angiogenesis assay. The utility of immunologically targeting GRIN2D in CRC was demonstrated by the vaccination approach inhibiting murine CRC tumour growth and vascularisation. GRIN2D represents a promising target for the future treatment of CRC.

Lymphocyte opioid receptors as innovative biomarkers of osteoarthritic pain, for the assessment and risk management of opioid tailored therapy, before hip surgery, to prevent chronic pain and opioid tolerance/addiction development: OpMarkArt (Opioids-Markers-Arthroprosthesis) study protocol for a randomized controlled trial

BACKGROUND

The incidence of post-surgical chronic pain ranges between 20% and 40% in Europe. Osteoarthritis pain after prosthesis implantation is one of the most severe secondary syndromes, depending not only on surgery but also on organic changes before and after joints replacement. No data are available about risk factors. An excessive inflammatory response plays a central role but a best therapy is not defined yet. It is not clear whether opioid administration could influence post-surgical pain and lead to tolerance or addiction. Interestingly, the immune system, together with the nervous and peptidergic ones, is involved in hypersensibility. The connection across the three biological systems lies in the presence of opioid receptors on immune cells surface. Here, we show a method to analyze whether opioids could modulate lymphocytes, by proposing opioid receptors as biological markers to prevent chronic pain and opioid tolerance or addiction after hip surgery.

METHODS/DESIGN

After institutional independent ethics committee approval, 60 patients, in pain and undergoing hip surgery, will be enrolled in a single-blind, randomized, phase IV, pilot study. Pain treatment will be selected inside a class of non-steroidal anti-inflammatory drugs (NAISDs) or paracetamol or a class of opioids, into three medication arms: 25 mg tapentadol twice daily; 75 mg tapentadol twice daily; NSAIDs or paracetamol in accordance with surgeon's custom. For each group, we will collect blood samples before, during and after surgery, to apply molecular analysis. We will perform lymphocyte opioid receptors genes and proteins expression and functional analysis. Data will be statistically analyzed.

DISCUSSION

This project has the potential to obtain a personalized diagnostic kit, by considering lymphocyte opioid receptors as biological markers. Starting from a simple blood sample, it will be possible to decide the best therapy for a single patient. Using a noninvasive approach, we expect to fix a daily standard dose and timing, before and after surgery, to bypass hip chronic pain and the insurgence of tolerance or addiction. The analysis of opioid receptors sensitivity will help to identify the best drug administration in each specific case (tailored therapy).

TRIAL REGISTRATION

ISRCTN, ISRCTN12559751 . Retrospectively registered on 23 May 2017.

Immunomodulatory effects of anesthetics in obese patients

Anesthesia and surgery have an impact on inflammatory responses, which influences perioperative homeostasis. Inhalational and intravenous anesthesia can alter immune-system homeostasis through multiple processes that include activation of immune cells (such as monocytes, neutrophils, and specific tissue macrophages) with release of pro- or anti-inflammatory interleukins, upregulation of cell adhesion molecules, and overproduction of oxidative radicals. The response depends on the timing of anesthesia, anesthetic agents used, and mechanisms involved in the development of inflammation or immunosuppression. Obese patients are at increased risk for chronic diseases and may have the metabolic syndrome, which features insulin resistance and chronic low-grade inflammation. Evidence has shown that obesity has adverse impacts on surgical outcome, and that immune cells play an important role in this process. Understanding the effects of anesthetics on immune-system cells in obese patients is important to support proper selection of anesthetic agents, which may affect postoperative outcomes. This review article aims to integrate current knowledge regarding the effects of commonly used anesthetic agents on the lungs and immune response with the underlying immunology of obesity. Additionally, it identifies knowledge gaps for future research to guide optimal selection of anesthetic agents for obese patients from an immunomodulatory standpoint.

Perioperative Anesthesia Care and Tumor Progression

This narrative review discusses the most recent up-to-date findings focused on the currently available "best clinical practice" regarding perioperative anesthesia care bundle factors and their effect on tumor progression. The main objective is to critically appraise the current literature on local anesthetics, regional outcome studies, opioids, and nonsteroidal anti-inflammatory drugs (NSAIDs) and their ability to decrease recurrence in patients undergoing cancer surgery. A brief discussion of additional topical perioperative factors relevant to the anesthesiologist including volatile and intravenous anesthetics, perioperative stress and anxiety, nutrition, and immune stimulation is included. The results of several recently published systematic reviews looking at the association between cancer recurrences and regional anesthesia have yielded inconclusive data and provide insufficient evidence regarding a definitive benefit of regional anesthesia. Basic science data suggests an anti tumor effect induced by local anesthetics. New refined animal models show that opioids can safely be used for perioperative pain management. Preliminary evidence suggests that NSAIDs should be an essential part of multimodal analgesia. Volatile anesthetics have been shown to increase tumor formation, whereas preclinical and emerging clinical data from propofol indicate tumor protective qualities. The perioperative period in the cancer patient represents a unique environment where surgically mediated stress response leads to immune suppression. Regional anesthesia techniques when indicated in combination with multimodal analgesia that include NSAIDs, opioids, and local anesthetics to prevent the pathophysiologic effects of pain and neuroendocrine stress response should be viewed as an essential part of balanced anesthesia.

Abhängigkeitspotenzial und andere Risiken von Opioidanalgetika im Alter

Zusammenfassung. Zielsetzung: Übersicht über Suchtpotenzial und andere Risiken von Opioidanalgetika im höheren Lebensalter. Methodik: Narrativ review. Literaturrecherche in PubMed (Suchbegriffe: opioid analgesics UND abuse; opioid analgesics UND dependence; opioid analgesics UND addiction; opioid analgesics UND adverse effects; jeweils UND elderly) sowie aktuellen einschlägigen Standardwerken; Auswahl nach altersmedizinischer Relevanz und Aktualität. Ergebnisse: Die Verordnung von Opioidanalgetika (OA) hat in den letzten 25 Jahren massiv zugenommen, die weitaus meisten Verordnungen entfallen auf alte Menschen und Menschen mit chronischen Nicht-Tumorschmerzen (CNTS). Die diagnostischen Kriterien für die Opiatabhängigkeit in ICD-10 und DSM-5 sind für die OA-Behandlung von CNTS ungeeignet. Bei langfristiger OA-Behandlung bei CNTS kann eine spezifische Form von Abhängigkeit entstehen, die nicht mit der illegalen Opiat-(Heroin-)Sucht gleichzusetzen ist. Vorbestehende Suchterkrankungen und andere psychische Störungen sind die wesentlichsten Risikofaktoren. Weitere Nebenwirkungen sind zu beachten. Schmerztherapie bei Suchtkranken stellt eine besondere Herausforderung dar. Schlussfolgerungen: Die Anwendung von OA bei CNTS verlangt eine sorgfältige Indikationsstellung. Die besondere Form der Abhängigkeit von OA ist nicht ausreichend erforscht und wird zu wenig beachtet.

Dose-dependent effects of morphine on lipopolysaccharide (LPS)-induced inflammation, and involvement of multixenobiotic resistance (MXR) transporters in LPS efflux in teleost fish

Opioid drugs, such as morphine (MO), detected in aquatic environments worldwide, may harm fish due to their semi-persistence and ability to potently interact with molecular targets conserved across vertebrates. Here, we established a waterborne bacterial lipopolysaccharide (LPS) challenge assay with zebrafish embryos as a model to investigate chemically-induced disruption of the innate immune system, and used it to study the effects of MO exposure. Exposure to 1 mg/L MO resulted in pronounced immunosuppression, reflected in downregulation of several inflammation-related genes, including myd88, trif, traf6, p38, nfκb2, il-1β, il-8 and ccl34a. Fish exposed to 1 mg/L MO accumulated 11.7 ng/g (wet weight) of MO, a concentration comparable to that reported in blood of chronic drug abusers subject to higher infection rates. Surprisingly, exposure to lower MO concentrations (100 ng/L-100 μg/L) led to exacerbation of LPS-induced inflammation. Two ATP-binding cassette (ABC) transporters known to be involved in the xenobiotic efflux - abcb4 and abcc2, also known as multixenobiotic resistance (MXR) transporters - were downregulated at 100 ng/L MO. We hypothesized that ABC/MXR transporters could modulate the severity of inflammation by being involved in efflux of LPS, thus regulating its accumulation in the organism. Indeed, we could demonstrate that blocking of ABC/MXR transporters by an inhibitor, cyclosporine A, results in stronger inflammation, coinciding with higher LPS accumulation, as visualized with fluorescently labeled LPS. Our work demonstrates that MO can disrupt fish innate immune responses at environmentally relevant concentrations. We also provide evidence for a role of ABC/MXR transporters in LPS efflux in fish. These finding may be applicable across other taxa, as ABC transporters are evolutionary conserved. Since diverse environmentally present chemicals are known to interfere with ABC/MXR transporters' expression or activity, our discovery raises concerns about potential adverse effects of such compounds on the immune system responses in aquatic organisms.

Prescription of Long-Acting Opioids and Mortality in Patients With Chronic Noncancer Pain

IMPORTANCE

Long-acting opioids increase the risk of unintentional overdose deaths but also may increase mortality from cardiorespiratory and other causes.

OBJECTIVE

To compare all-cause mortality for patients with chronic noncancer pain who were prescribed either long-acting opioids or alternative medications for moderate to severe chronic pain.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study between 1999 and 2012 of Tennessee Medicaid patients with chronic noncancer pain and no evidence of palliative or end-of-life care.

EXPOSURES

Propensity score-matched new episodes of prescribed therapy for long-acting opioids or either analgesic anticonvulsants or low-dose cyclic antidepressants (control medications).

MAIN OUTCOMES AND MEASURES

Total and cause-specific mortality as determined from death certificates. Adjusted hazard ratios (HRs) and risk differences (difference in incidence of death) were calculated for long-acting opioid therapy vs control medication.

RESULTS

There were 22,912 new episodes of prescribed therapy for both long-acting opioids and control medications (mean [SD] age, 48 [11] years; 60% women). The long-acting opioid group was followed up for a mean 176 days and had 185 deaths and the control treatment group was followed up for a mean 128 days and had 87 deaths. The HR for total mortality was 1.64 (95% CI, 1.26-2.12) with a risk difference of 68.5 excess deaths (95% CI, 28.2-120.7) per 10,000 person-years. Increased risk was due to out-of-hospital deaths (154 long-acting opioid, 60 control deaths; HR, 1.90; 95% CI, 1.40-2.58; risk difference, 67.1; 95% CI, 30.1-117.3) excess deaths per 10,000 person-years. For out-of-hospital deaths other than unintentional overdose (120 long-acting opioid, 53 control deaths), the HR was 1.72 (95% CI, 1.24-2.39) with a risk difference of 47.4 excess deaths (95% CI, 15.7-91.4) per 10,000 person-years. The HR for cardiovascular deaths (79 long-acting opioid, 36 control deaths) was 1.65 (95% CI, 1.10-2.46) with a risk difference of 28.9 excess deaths (95% CI, 4.6-65.3) per 10,000 person-years. The HR during the first 30 days of therapy (53 long-acting opioid, 13 control deaths) was 4.16 (95% CI, 2.27-7.63) with a risk difference of 200 excess deaths (95% CI, 80-420) per 10,000 person-years.

CONCLUSIONS AND RELEVANCE

Prescription of long-acting opioids for chronic noncancer pain, compared with anticonvulsants or cyclic antidepressants, was associated with a significantly increased risk of all-cause mortality, including deaths from causes other than overdose, with a modest absolute risk difference. These findings should be considered when evaluating harms and benefits of treatment.

Heroin inhibits HIV-restriction miRNAs and enhances HIV infection of macrophages

Although opioids have been extensively studied for their impact on the immune system, limited information is available about the specific actions of opioids on intracellular antiviral innate immunity against HIV infection. Thus, we investigated whether heroin, one of the most abused drugs, inhibits the expression of intracellular HIV restriction microRNA (miRNA) and facilitates HIV replication in macrophages. Heroin treatment of macrophages enhanced HIV replication, which was associated with the downregulation of several HIV restriction miRNAs. These heroin-mediated actions on the miRNAs and HIV could be antagonized by naltrexone, an opioid receptor antagonist. Furthermore, the in vitro negative impact of heroin on HIV-associated miRNAs was confirmed by the in vivo observation that heroin addicts had significantly lower levels of macrophage-derived HIV restriction miRNAs than those in the control subjects. These in vitro and in vivo findings indicate that heroin use compromises intracellular anti-HIV innate immunity, providing a favorable microenvironment for HIV survival in the target cells.

Opioid Receptors

Opioids are the oldest and most potent drugs for the treatment of severe pain. Their clinical application is undisputed in acute (e.g., postoperative) and cancer pain, but their long-term use in chronic pain has met increasing scrutiny. This article reviews mechanisms underlying opioid analgesia and other opioid actions. It discusses the structure, function, and plasticity of opioid receptors; the central and peripheral sites of analgesic actions and side effects; endogenous and exogenous opioid receptor ligands; and conventional and novel opioid compounds. Challenging clinical situations, such as the tension between chronic pain and addiction, are also illustrated.

Opioid treatment of experimental pain activates nuclear factor-κB

OBJECTIVE

To determine the independent and combined effects of pain and opioids on the activation of an early marker of inflammation, nuclear factor-κB (NF-κB).

DESIGN

NF-κB activation was compared within-subjects following four randomly ordered experimental sessions of opioid-only (intravenous fentanyl 1 μg/kg), painonly (cold-pressor), opioid + pain, and a resting condition.

SETTING

University General Clinical Research Center.

PARTICIPANTS

Twenty-one (11 female) healthy controls.

INTERVENTIONS

Following exposure to treatment (fentanyl administration and/or cold-pressor pain), blood samples for NF-κB analysis were obtained.

MAIN OUTCOME MEASURES

Intracellular levels of activated NF-κB, in unstimulated and stimulated peripheral blood mononuclear cells at 15 and 30 minutes.

RESULTS

Neither pain nor opioid administration alone effected NF-κB levels in cell populations; however, the combination of treatments induced significant increases of NF-κB in stimulated peripheral blood mononuclear cell, lymphocytes, and monocytes.

CONCLUSIONS

The combination of acute pain with opioids, as occurs in clinical situations, activates a key transcription factor involved in proinflammatory responses.

Burn wound healing and treatment: review and advancements

Burns are a prevalent and burdensome critical care problem. The priorities of specialized facilities focus on stabilizing the patient, preventing infection, and optimizing functional recovery. Research on burns has generated sustained interest over the past few decades, and several important advancements have resulted in more effective patient stabilization and decreased mortality, especially among young patients and those with burns of intermediate extent. However, for the intensivist, challenges often exist that complicate patient support and stabilization. Furthermore, burn wounds are complex and can present unique difficulties that require late intervention or life-long rehabilitation. In addition to improvements in patient stabilization and care, research in burn wound care has yielded advancements that will continue to improve functional recovery. This article reviews recent advancements in the care of burn patients with a focus on the pathophysiology and treatment of burn wounds.

Safety issues of current analgesics: an update

Pain represents a complex experience which can be approached by various medicines. Non-opioid and opioid analgesics are the most common drugs used to manage different types of pain. The increased attention nowadays to pain management entailed concomitantly more frequent adverse drug reactions (ADRs) related to analgesic use. Drug-drug interactions can be sometimes responsible for the adverse effects. However, a significant proportion of analgesic ADRs are preventable, which would avoid patient suffering. In order to draw the attention to analgesics risks and to minimize the negative consequences related to their use, the present review comprises a synthesis of the most important safety issues described in the scientific literature. It highlights the potential risks of the most frequently used analgesic medicines: non-opioid (paracetamol, metamizole, non-steroidal anti-inflammatory drugs) and opioid analgesics. Even if there is a wide experience in their use, they continue to capture attention with safety concerns and with potential risks recently revealed. Acknowledging potential safety problems represents the first step for health professionals in assuring a safe and efficient analgesic treatment with minimum risks to patients. Taking into consideration all medical and environmental factors and carefully monitoring the patients are also essential in preventing and early detecting analgesic ADRs.

Opioid-induced central immune signaling: implications for opioid analgesia

Despite being the mainstay of pain management, opioids are limited in their clinical utility by adverse effects, such as tolerance and paradoxical hyperalgesia. Research of the past 15 years has extended beyond neurons, to implicate central nervous system immune signaling in these adverse effects. This article will provide an overview of these central immune mechanisms in opioid tolerance and paradoxical hyperalgesia, including those mediated by Toll-like receptor 4, purinergic, ceramide, and chemokine signaling. Challenges for the future, as well as new lines of investigation will be highlighted.

Pelvic pain: a pathway for care developed for both men and women by the British Pain Society

This paper aims to explain the key points and highlight some of the controversies in the development of the British Pain Society's pelvic pain patient pathway map. Many clinicians lack experience and confidence with this group of patients, and this issue is highlighted. Additionally, the difficulties of classification and definitions in this area are discussed in detail. These are historical causes of disagreement among specialists which can lead to confused clinical care. This group of patients have multiple issues that cross many professional boundaries; they are best managed by the co-ordinated involvement of multiple teams. Patients suffer from significant distress and disability that often needs specialist assessment and intervention (interdisciplinary). This suggests that an integrated approach is required across the historic boundaries of primary and secondary care. A variety of interventions, including opioids and neuromodulation are recommended in the pathway and the controversies surrounding these inclusions are aired in detail.

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

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

The 2013 EAU guidelines on chronic pelvic pain: is management of chronic pelvic pain a habit, a philosophy, or a science? 10 years of development

CONTEXT

Progress in the science of pain has led pain specialists to move away from an organ-centred understanding of pain located in the pelvis to an understanding based on the mechanism of pain and integrating, as far as possible, psychological, social, and sexual dimensions of the problem. This change is reflected in all areas, from taxonomy through treatment. However, deciding what is adequate investigation to rule out treatable disease before moving to this way of engaging with the patient experiencing pain is a complex process, informed by pain expertise as much as by organ-based medical knowledge.

OBJECTIVE

To summarise the evolving changes in the management of patients with chronic pelvic pain by referring to the 2012 version of the European Association of Urology (EAU) guidelines on chronic pelvic pain.

EVIDENCE ACQUISITION

The working panel highlights some of the most important aspects of the management of patients with chronic pelvic pain emerging in recent years in the context of the EAU guidelines on chronic pelvic pain. The guidelines were completely updated in 2012 based on a systematic review of the literature from online databases from 1995 to 2011. According to this review, levels of evidence and grades of recommendation were added to the text. A full version of the guidelines is available at the EAU office or Web site (www.uroweb.org).

EVIDENCE SYNTHESIS

The previously mentioned issues are explored in this paper, which refers throughout to dilemmas for the physician and treatment team as well as to the need to inform and engage the patient in a collaborative empirical approach to pain relief and rehabilitation. These issues are exemplified in two case histories.

CONCLUSIONS

Chronic pelvic pain persisting after appropriate treatment requires a different approach focussing on pain. This approach integrates the medical, psychosocial, and sexual elements of care to engage the patient in a collaborative journey towards self-management.