Opioids and immune modulation: more questions than answers

Nanotechnology-Enhanced Naloxone and Alternative Treatments for Opioid Addiction

Opioids are commonly prescribed to address intense, ongoing pain associated with cancer, as well as long-lasting noncancer-related pain when alternative methods have proven ineffective. Individuals who exhibit both chronic pain and misuse of opioids face a significant danger of experiencing adverse health outcomes and the potential loss of life related to opioid use. Thus, there is a current movement to prescribe naloxone to those considered high-risk for opioid overdose. Naloxone has been explored as an antidote to reverse acute respiratory depression. Conversely, naloxone can give rise to other problems, including hypertension and cardiac arrhythmias. Thus, the importance of nanotechnology-enabled drug delivery strategies and their role in mitigating naloxone side-effects are significant. In this review, we explore the latest advancements in nanotechnology-enabled naloxone and alternative methods for addressing the opioid crisis through the utilization of non-opioid natural alternatives for chronic pain management.

Injection Drug Use Alters Plasma Regulation of the B Cell Response

The opioid epidemic continues to be a major public health issue that includes millions of people who inject drugs (PWID). PWID have increased incidence of serious infections, including HIV as well as metabolic and inflammatory sequelae. We sought to discern the extent of systemic alterations in humoral immunity associated with injection drug use, including alterations in the plasma proteome and its regulation of B cell responsiveness. Comprehensive plasma proteomics analysis of HIV negative/hepatitis C negative individuals with a history of recent injection heroin use was performed using mass spectrometry and ELISA. The effects of plasma from PWID and healthy controls on the in vitro proliferation and transcriptional profile of B cell responses to stimulation were determined by flow cytometry and RNA-Seq. The plasma proteome of PWID was distinct from healthy control individuals, with numerous immune-related analytes significantly altered in PWID, including complement (C3, C5, C9), immunoglobulin (IgD, IgM, kappa light chain), and other inflammatory mediators (CXCL4, LPS binding protein, C-reactive protein). The plasma of PWID suppressed the in vitro proliferation of B cells. Transcriptome analysis indicated that PWID plasma treatment increased B cell receptor and CD40 signaling and shifted B cell differentiation from plasma cell-like toward germinal center B cell-like transcriptional profiles. These results indicate that the systemic inflammatory milieu is substantially altered in PWID and may impact their B cell responses.

The Surgical Stress Response and Anesthesia: A Narrative Review

The human physiological response "to stress" includes all metabolic and hormonal changes produced by a traumatic event at the micro or macro cellular levels. The main goal of the body's first response to trauma is to keep physiological homeostasis. The perioperative non-specific adaptation response can sometimes be detrimental and can produce systemic inflammatory response syndrome (SIRS), characterized by hypermetabolism and hyper catabolism. We performed a narrative review consisting of a description of the surgical stress response's categories of changes (neurohormonal and immunological response) followed by reviewing methods found in published studies to modulate the surgical stress response perioperatively. We described various preoperative measures cited in the literature as lowering the burden of surgical trauma. This article revises the anesthetic drugs and techniques that have an impact on the surgical stress response and proven immune-modulatory effects. We also tried to name present knowledge gaps requiring future research. Our review concludes that proper preoperative measures, adequate general anesthetics, multimodal analgesia, early postoperative mobilization, and early enteral nutrition can decrease the stress response to surgery and ease patient recovery. Anesthetics and analgesics used during the perioperative period may modulate the innate and adaptive immune system and inflammatory system, with a consecutive impact on cancer recurrence and long-term outcomes.

Blocking μ-opioid receptor by naltrexone exaggerates oxidative stress and airway inflammation via the MAPkinase pathway in a murine model of asthma

Opioids regulate various physiological and pathophysiological functions, including cell proliferation, immune function, obesity, and neurodegenerative disorders. They have been used for centuries as a treatment for severe pain, binding to opioid receptors a specific G protein-coupled receptor. Common opioids, like β-endorphin, [D-Ala2, N-MePhe4, Gly-ol]-enkephalin (DAMGO), and dynorphins, have analgesic effects. The use of a potent antagonist, like naltrexone hydrochloride, to block the effects of mu Opioid Receptor (μOR) may result in the withdrawal of physiological effects and could potentially impact immune responses in many diseases including respiratory disease. Asthma is a respiratory disease characterized by airway hyperresponsiveness, inflammation, bronchoconstriction, chest tightness, stress generation and release of various cytokines. Airway inflammation leads recruitment and activation of immune cells releasing mediators, including opioids, which may modulate inflammatory response by binding to their respective receptors. The study aims to explore the role of μOR antagonist (naltrexone) in regulating asthma pathophysiology, as the regulation of immune and inflammatory responses in asthma remains unclear. Balb/c mice were sensitized intranasally by 1% TDI and challenged with 2.5% TDI. Naltrexone hydrochloride (1 mg/kg body weight) was administered through intraperitoneal route 1 h before TDI induction. Blocking μOR by naltrexone exacerbates airway inflammation by recruiting inflammatory cells (lymphocytes and neutrophils), enhancing intracellular Reactive oxygen species in bronchoalveolar lavage fluid (BALF), and inflammatory mediator (histamine, Eosinophil peroxidase and neutrophil elastase) in lungs. Naltrexone administration modulated inflammatory cytokines (TNF-α, IL-4, IL-5, IL-6, IL-10, and IL-17A), and enhanced IgE and CRP levels. Naltrexone administration also increased the expression of NF-κB, and phosphorylated p-P38, p-Erk, p-JNK and NF-κB by inhibiting the μOR. Docking study revealed good binding affinity of naltrexone with μOR compared to δ and κ receptors. In future it might elucidate potential therapeutic against many respiratory pathological disorders. In conclusion, μOR blocking by naltrexone regulates and implicates inflammation, bronchoconstriction, and lung physiology.

Injecting drug use and hepatitis C virus infection independently increase biomarkers of inflammatory disease risk which are incompletely restored by curative direct-acting antiviral therapy

Background

Hepatitis C virus (HCV) infections are more prevalent in people who inject drugs (PWID) who often experience additional health risks. HCV induces inflammation and immune alterations that contribute to hepatic and non-hepatic morbidities. It remains unclear whether curative direct acting antiviral (DAA) therapy completely reverses immune alterations in PWID.

Methods

Plasma biomarkers of immune activation associated with chronic disease risk were measured in HCV-seronegative (n=24) and HCV RNA+ (n=32) PWID at baseline and longitudinally after DAA therapy. Adjusted generalised estimating equations were used to assess longitudinal changes in biomarker levels. Comparisons between community controls (n=29) and HCV-seronegative PWID were made using adjusted multiple regression modelling.

Results

HCV-seronegative PWID exhibited significantly increased levels of inflammatory biomarkers including soluble (s) TNF-RII, IL-6, sCD14 and sCD163 and the diabetes index HbA1c as compared to community controls. CXCL10, sTNF-RII, vascular cell adhesion molecule-1 and lipopolysaccharide binding protein (LBP) were additionally elevated in PWID with viremic HCV infection as compared to HCV- PWID. Whilst curative DAA therapy reversed some biomarkers, others including LBP and sTNF-RII remained elevated 48 weeks after HCV cure.

Conclusion

Elevated levels of inflammatory and chronic disease biomarkers in PWID suggest an increased risk of chronic morbidities such as diabetes and cardiovascular disease. HCV infection in PWID poses an additional disease burden, amplified by the incomplete reversal of immune dysfunction following DAA therapy. These findings highlight the need for heightened clinical surveillance of PWID for chronic inflammatory diseases, particularly those with a history of HCV infection.

Anti-Algics in the Therapeutic Response of Breast and Urological Cancers

The effect of anti-algics on tumor progression and the overall survival of patients is controversial and remains unclear. Herein, we disclose the in vitro effects of the local anesthetics lidocaine, ropivacaine, and levobupivacaine on breast (MCF7), prostate (PC3, LNCaP), and bladder (TCCSUP, HT1376) cancer cell lines, both as monotherapy and in combination with standard-of-care therapeutics. Assays for cell proliferation, viability, death profile, and migration were performed. Additionally, we explored the clinical outcomes of opioid use through a cross-sectional study involving 200 metastatic prostate cancer patients. The main clinical data collected included the type of opioid therapy administered, dosage, treatment duration, disease progression, and overall survival. Results obtained demonstrate that treatment with local anesthetics has a promising selective anti-tumor effect on these types of cancer, with higher effects when associated with docetaxel. This points out the use of local anesthetics as an added value in the treatment of prostate carcinoma patients. Alternatively, chronic opioid use was correlated with reduced overall survival (p < 0.05) and progression-free survival (p < 0.05) at each treatment line in the observational study. While these results provide valuable insights, larger prospective studies are imperative to comprehensively evaluate the clinical impact of opioid analgesics in prostate cancer patients.

Association between opioid abuse and COVID-19 susceptibility: a propensity score matched study

BACKGROUND

Opioid use disorder (OUD) has been associated with adverse health outcomes, and its potential impact on COVID-19 outcomes is of significant concern. This study aimed to assess the susceptibility and clinical outcomes of hospitalized COVID-19 patients with OUD using a propensity score-matched design.

METHODS

A historical cohort study was conducted in Alborz province, Iran, during the early months of the COVID-19 pandemic. Patients aged 18 years and above with confirmed COVID-19 were included in the study. OUD was defined as a compulsive urge to use opioids or opioid-derivative drugs. Non-opioid abusers with COVID-19 were selected as the control group. Data on demographics, clinical characteristics, laboratory factors, comorbidities, and vital signs were collected. Propensity score matching (PSM) was used to balance the groups and assess the impact of OUD on ICU admission, mortality, the need for intubation, and the severity of pulmonary involvement on CT scans.

RESULTS

A total of 442 patients were included in the study, with 351 discharged and 34 deceased. The PSM analysis showed that OUD was not significantly associated with ICU admission (OR: 1.87, 95% CI: 0.22-2.91, p = 0.631). However, opium users had an increased risk of mortality (OR: 2.38, 95% CI: 1.30-4.35, p = 0.005) and a higher likelihood of requiring intubation (OR: 3.57, 95% CI: 1.38-9.39, p = 0.009) compared to non-opioid abusers. The severity of pulmonary involvement on CT scans did not show a significant association with OUD.

CONCLUSION

OUD among hospitalized COVID-19 patients was associated with an increased risk of mortality and the need for intubation. These findings highlight the importance of addressing OUD as a potential risk factor in the management and treatment of COVID-19 patients. Further research is warranted to explore the underlying mechanisms and develop appropriate interventions to mitigate the impact of OUD on COVID-19 outcomes.

Prenatal alcohol exposure promotes NLRP3 inflammasome-dependent immune actions following morphine treatment and paradoxically prolongs nerve injury-induced pathological pain in female mice

BACKGROUND

Neuroimmune dysregulation from prenatal alcohol exposure (PAE) may contribute to neurological deficits associated with fetal alcohol spectrum disorders (FASD). PAE is a risk factor for developing peripheral immune and spinal glial sensitization and release of the proinflammatory cytokine IL-1β, which lead to neuropathic pain (allodynia) from minor nerve injury. Although morphine acts on μ-opioid receptors, it also activates immune receptors, TLR4, and the NLRP3 inflammasome that induces IL-1β. We hypothesized that PAE induces NLRP3 sensitization by morphine following nerve injury in adult mice.

METHODS

We used an established moderate PAE paradigm, in which adult PAE and non-PAE control female mice were exposed to a minor sciatic nerve injury, and subsequent allodynia was measured using the von Frey fiber test. In control mice with standard sciatic damage or PAE mice with minor sciatic damage, the effects of the NLRP3 inhibitor, MCC950, were examined during chronic allodynia. Additionally, minor nerve-injured mice were treated with morphine, with or without MCC950. In vitro studies examined the TLR4-NLRP3-dependent proinflammatory response of peripheral macrophages to morphine and/or lipopolysaccharide, with or without MCC950.

RESULTS

Mice with standard sciatic damage or PAE mice with minor sciatic damage developed robust allodynia. Blocking NLRP3 activation fully reversed allodynia in both control and PAE mice. Morphine paradoxically prolonged allodynia in PAE mice, while control mice with minor nerve injury remained stably non-allodynic. Allodynia resolved sooner in nerve-injured PAE mice without morphine treatment than in morphine-treated mice. MCC950 treatment significantly shortened allodynia in morphine-treated PAE mice. Morphine potentiated IL-1β release from TLR4-activated PAE immune cells, while MCC950 treatment greatly reduced it.

CONCLUSIONS

In female mice, PAE prolongs allodynia following morphine treatment through NLRP3 activation. TLR4-activated PAE immune cells showed enhanced IL-1β release with morphine via NLRP3 actions. Similar studies are needed to examine the adverse impact of morphine in males with PAE. These results are predictive of adverse responses to opioid pain therapeutics in individuals with FASD.

Effects of epidural anesthesia on the prognosis of ovarian cancer-a systematic review and meta-analysis

INTRODUCTION

The global low survival rate among ovarian cancer patients has resulted in significant social and economic burdens. Nevertheless, previous studies have produced mixed results when exploring the link between anesthetic techniques and the prognosis of ovarian cancer. The study aims to compare the effect of epidural anesthesia with general anesthesia on survival time after cytoreductive surgery in patients with ovarian cancer.

METHODS

The PubMed (National Library of Medicine), Cochrane library, Web of science, Embase, CNKI (China National Knowledge Internet), Wanfang Med Online (China database), were systematically searched from inception to May, 2023, using the Medical Subject Headings [MeSH] of "Ovarian Neoplasm" and "Anesthesia, Epidural" and free words to identify systematic reviews or meta-analyses. The research methodology involved analyzing randomized controlled trials (RCTs), as well as prospective or retrospective cohort studies, which compared the long-term prognosis of patients with ovarian cancer under general anesthesia combined with epidural anesthesia (GEA) versus general anesthesia alone (GA). The Newcastle Ottawa Scale (NOS) was used to assess methodological quality and bias. Data extraction and assessment of study quality were conducted by two independent reviewers. A meta-analysis was then performed to calculate hazard ratios (HRs) and corresponding 95% confidence intervals (CIs). Overall survival (OS) was defined as the primary outcome, time to tumor recurrence (TTR) was the secondary outcome. Epidural anesthesia could be used intraoperatively and immediately postoperatively (EIP), or postoperatively only (EP). GEA includes EIP and EP.

RESULTS

In total, 8 retrospective cohort studies with 2036 participants met the inclusion criteria. The pooled results demonstrated that GEA could extend OS (HR 0.75, 95% CI 0.67-0.84, I2 = 0%, P < 0.05, fixed-effect model) when compared with GA in ovarian cancer patients undergoing cytoreductive surgery, but not TTR (sensitivity analysis revealed substantial heterogeneity among the included studies). The result of analyzing a total of 1490 patients in 4 studies was that EIP had a better prognosis on OS than GA (HR 0.68, 95%CI 0.55-0.85, I2 = 61%, P < 0.05, random-effect model). However, EP had no advantage in TTR (sensitivity analysis revealed it was unstable outcome). Ovarian cancer FIGO(International Federation of Gynecology and Obstetrics) stage III, stage IV compared to stage I on OS was statistically significant, HRs respectively are 3.67 (95%CI 2.25-5.98), I2 = 0%, fixed-effect model, P < 0.05, and 7.43 (95%CI 3.67-15.03), I2 = 31%, fixed-effect model, P < 0.05, but there was no statistically significant difference between stage II and stage I, HR 2.00, 95%CI0.98-4.09, I2 = 0%, fixed-effect model, P > 0.05. 1-10 mm tumor residuals shorten TTR compared with 0 residuals, HR 1.75, 95% CI1.50-2.04, I2 = 0%, fixed-effect model, P < 0.05.

CONCLUSIONS

It is hard to conclude that postoperative epidural analgesia offers greater benefits than GA. However, general anesthesia combined with epidural anesthesia (EIP) can improve overall survival in ovarian cancer patients, allowing the anesthesiologist to use anesthesia techniques to provide a favorable prognosis for the ovarian cancer patient. Tumor staging and the extent of cell reduction are also critical factors that significantly influence the long-prognosis of ovarian cancer patients.

Type of anesthesia for cancer resection surgery: No differential impact on cancer recurrence in mouse models of breast cancer

BACKGROUND

Surgery is essential for curative treatment of solid tumors. Evidence from recent retrospective clinical analyses suggests that use of propofol-based total intravenous anesthesia during cancer resection surgery is associated with improved overall survival compared to inhaled volatile anesthesia. Evaluating these findings in prospective clinical studies is required to inform definitive clinical guidelines but will take many years and requires biomarkers to monitor treatment effect. Therefore, we examined the effect of different anesthetic agents on cancer recurrence in mouse models of breast cancer with the overarching goal of evaluating plausible mechanisms that could be used as biomarkers of treatment response.

METHODS

To test the hypothesis that volatile anesthesia accelerates breast cancer recurrence after surgical resection of the primary tumor, we used three mouse models of breast cancer. We compared volatile sevoflurane anesthesia with intravenous propofol anesthesia and used serial non-invasive bioluminescent imaging to track primary tumor recurrence and metastatic recurrence. To determine short-term perioperative effects, we evaluated the effect of anesthesia on vascular integrity and immune cell changes after surgery in animal models.

RESULTS

Survival analyses found that the kinetics of cancer recurrence and impact on survival were similar regardless of the anesthetic agent used during cancer surgery. Vascular permeability, immune cell infiltration and cytokine profiles showed no statistical difference after resection with inhaled sevoflurane or intravenous propofol anesthesia.

CONCLUSIONS

These preclinical studies found no evidence that choice of anesthetic agent used during cancer resection surgery affected either short-term perioperative events or long-term cancer outcomes in mouse models of breast cancer. These findings raise the possibility that mouse models do not recapitulate perioperative events in cancer patients. Nonetheless, the findings suggest that future evaluation of effects of anesthesia on cancer outcomes should focus on cancer types other than breast cancer.

Opioids and opioid receptors; understanding pharmacological mechanisms as a key to therapeutic advances and mitigation of the misuse crisis

Opioids are a mainstay in acute pain management and produce their effects and side effects (e.g., tolerance, opioid-use disorder and immune suppression) by interaction with opioid receptors. I will discuss opioid pharmacology in some controversial areas of enquiry of anaesthetic relevance. The main opioid target is the µ (mu,MOP) receptor but other members of the opioid receptor family, δ (delta; DOP) and κ (kappa; KOP) opioid receptors also produce analgesic actions. These are naloxone-sensitive. There is important clinical development relating to the Nociceptin/Orphanin FQ (NOP) receptor, an opioid receptor that is not naloxone-sensitive. Better understanding of the drivers for opioid effects and side effects may facilitate separation of side effects and production of safer drugs. Opioids bind to the receptor orthosteric site to produce their effects and can engage monomer or homo-, heterodimer receptors. Some ligands can drive one intracellular pathway over another. This is the basis of biased agonism (or functional selectivity). Opioid actions at the orthosteric site can be modulated allosterically and positive allosteric modulators that enhance opioid action are in development. As well as targeting ligand-receptor interaction and transduction, modulating receptor expression and hence function is also tractable. There is evidence for epigenetic associations with different types of pain and also substance misuse. As long as the opioid narrative is defined by the 'opioid crisis' the drive to remove them could gather pace. This will deny use where they are effective, and access to morphine for pain relief in low income countries.

Prenatal opioid exposure and risk of asthma in childhood: a population-based study from Denmark, Norway, and Sweden

Background: Opioids may modulate the immune function through opioid receptors on immune cells. Long-term consequences of prenatal opioid exposure on the immune system, such as childhood asthma, are unknown. Objectives: To investigate whether prenatal opioid exposure is associated with the risk of childhood asthma. Methods: Cohort study using linked nationwide registers in Denmark (1996-2015), Norway (2005-2015), and Sweden (2006-2013). Children born by mothers who were chronic opioid analgesics users before pregnancy (n = 14,764) or who were receiving opioid maintenance therapy (OMT) before or during pregnancy (n = 1,595) were identified based on information from each of the medical birth registers and prescription registers. Long-term opioid analgesics exposed children were compared to short-term exposed or unexposed, whereas OMT exposed children were compared to OMT unexposed. Asthma among children ≥1 years of age was defined as two or more filled prescriptions of antiasthmatic medication within 365 days, or a diagnosis of asthma. Hazard ratios (HRs) were calculated using Cox proportional hazards regression with attained age as the time scale. Inverse probability of treatment weights based on propensity scores were applied to adjust for measured confounders. Individual level data from Norway and Sweden were pooled, whereas individual level data from Denmark were analyzed separately. For the opioid analgesics comparisons, adjusted HRs (aHR) from the combined Norwegian/Swedish data and the Danish data were pooled in a fixed-effects meta-analysis. Results: For the opioid analgesics cohort, no increased risk of asthma was observed in long-term exposed children neither compared with unexposed [aHR = 0.99 (95% CI 0.87-1.12)], nor compared with short-term exposed [aHR = 0.97 (0.86-1.10)]. No increased risk of asthma was observed in OMT exposed compared with OMT unexposed children [Norway/Sweden: aHR = 1.07 (0.60-1.92), Denmark: aHR = 1.25 (0.87-1.81)]. Results from sensitivity analyses, where potential misclassification of the outcome and misclassification of OMT exposure were assessed, as well as starting follow-up at 6 years of age, showed that the estimates of association were generally robust. Conclusion: We found no association between prenatal exposure to opioids and risk of childhood asthma. Results were consistent across two different opioid exposure groups with different confounder distributions.

Perioperative opioids: a narrative review contextualising new avenues to improve prescribing

Opioids have dominated the management of perioperative pain in recent decades with higher doses than ever before used in some circumstances. Through the expanding use of opioids, growing research has highlighted their associated side-effects and the intertwined phenomena of acute withdrawal syndrome, opioid tolerance, and opioid-induced hyperalgesia. With multiple clinical guidelines now endorsing multimodal analgesia, a diverse array of opioid-sparing agents emerges and has been studied to variable degrees, including techniques of opioid-free anaesthesia. It remains unclear to what extent such methods should be adopted, yet current evidence does suggest dependence on opioids as the primary perioperative analgesic might not meet the principles of 'rational prescribing' as described by Maxwell. In this narrative review we describe how, using current evidence, a patient-centred rational-prescribing approach can be applied to opioids in the perioperative period. To contextualise this approach, we discuss the historical adoption of opioids in anaesthesia, our growing understanding of associated side-effects and emerging strategies of opioid-sparing and opioid-free anaesthesia. We discuss avenues and challenges for improving opioid prescribing to limit persistent postoperative opioid use and how these may be incorporated into a rational-prescribing approach.

Effect of sevoflurane-remifentanil and propofol-remifentanil anesthesia on glycocalyx shedding during deep inferior epigastric perforator flap breast reconstruction: a prospective randomized, controlled trial

BACKGROUND

The endothelial glycocalyx (EG) is an important structure that regulates vascular homeostasis. Deep inferior epigastric perforator (DIEP) flap is expected to cause substantial EG breakdown owing to the long procedural duration and ischemia- reperfusion injury. This prospective, randomized, controlled study aimed to compare syndecan-1 levels during sevoflurane-remifentanil and propofol-remifentanil anesthesia in patients who underwent DIEP flap breast reconstruction.

METHODS

Fifty-one patients were randomized to either sevoflurane (n = 26) or propofol (n = 25) groups. Anesthesia was maintained with remifentanil in combination with either sevoflurane or propofol. The primary endpoint was the concentration of serum syndecan-1 measured at 1 h after surgery.

RESULTS

Fifty patients (98.0%) completed the study. Patients in the propofol group had significantly lower levels of syndecan-1 than patients in the sevoflurane group at 1 h after operation (23.8 ± 1.6 vs. 30.9 ± 1.7 ng/ml, respectively; Bonferroni corrected P = 0.012). There were no significant differences between groups in postoperative complications. The postoperative hospital stay was 8.4 ± 2.5 days in the sevoflurane group and 7.4 ± 1.0 days in the propofol group (P = 0.077).

CONCLUSIONS

Propofol-remifentanil anesthesia resulted in lesser increases in syndecan-1 levels compared to increases with sevoflurane-remifentanil anesthesia in patients who underwent DIEP flap reconstruction. Our results suggest that propofol-remifentanil anesthesia shows protective effects against EG damage during DIEP flap breast reconstruction in contrast to sevoflurane-remifentanil anesthesia.

Altered Membrane Expression and Function of CD11b Play a Role in the Immunosuppressive Effects of Morphine on Macrophages at the Nanomolar Level

Morphine, one of the most efficacious analgesics, is effective in severe pain, especially in patients with concomitant painful cancers. The clinical use of morphine may be accompanied by increased immunosuppression, susceptibility to infection and postoperative tumor metastatic recurrence, and the specific mechanisms and clinical strategies to alleviate this suppression remain to be investigated. Expression of CD11b is closely associated with the macrophage phagocytosis of xenobiotic particles, bacteria or tumor cells. Here, we find that morphine at 0.1-10 nM levels inhibited CD11b expression and function on macrophages via a μ-opioid receptor (MOR)-dependent mechanism, thereby reducing macrophage phagocytosis of tumor cells, a process that can be reversed by thymopentin (TP5), a commonly used immune-enhancing adjuvant in clinical practice. By knocking down or overexpressing MOR on macrophages and using naloxone, an antagonist of the MOR receptor, and LA1, a molecule that promotes macrophage CD11b activation, we suggest that morphine may regulate macrophage phagocytosis by inhibiting the surface expression and function of macrophage CD11b through the membrane expression and activation of MOR. The CD47/SIRPα axis, which is engaged in macrophage-tumor immune escape, was not significantly affected by morphine. Notably, TP5, when combined with morphine, reversed the inhibition of macrophage phagocytosis by morphine through mechanisms that promote membrane expression of CD11b and modulate its downstream signaling (e.g., NOS2, IFNG, IL1B and TNFA, as well as AGR1, PDGFB, IL6, STAT3, and MYC). Thus, altered membrane expression and function of CD11b may mediate the inhibition of macrophage phagocytosis by therapeutic doses of morphine, and the reversal of this process by TP5 may provide an effective palliative option for clinical immunosuppression by morphine.

Virally Suppressed People Living with HIV Who Use Opioids Have Diminished Latency Reversal

Of the 12 million people who inject drugs worldwide, 13% live with HIV. Whether opioid use impacts HIV pathogenesis and latency is an outstanding question. To gain insight into whether opioid use influences the proviral landscape and latent HIV reservoir, we performed intact proviral DNA assays (IPDA) on peripheral blood mononuclear cells (PBMCs) from antiretroviral therapy (ART)-suppressed people living with HIV (PWH) with or without current opioid use. No differences were observed between PWH with and without opioid use in the frequency of HIV intact and defective proviral genomes. To evaluate the latent reservoir, we activated PBMCs from ART-suppressed PWH with or without opioid use and assessed the induction of HIV RNA. PWH using opioids had diminished responses to ex vivo HIV reactivation, suggesting a smaller reversible reservoir of HIV-1 latently infected cells. However, in vitro studies using primary CD4+ T cells treated with morphine showed no effect of opioids on HIV-1 infection, replication or latency establishment. The discrepancy in our results from in vitro and clinical samples suggests that while opioids may not directly impact HIV replication, latency and reactivation in CD4+ T cells, opioid use may indirectly shape the HIV reservoir in vivo by modulating general immune functions.

Knowledge Mapping of Opioids and Immunomodulation: A Bibliometric Analysis (2000-2022)

Background

Increasing evidence indicates that opioids markedly affect the immune system. However, there are few studies on opioids and immunomodulation using bibliometric analysis.

Purpose

We aimed to provide a comprehensive overview of the research status and trends of the influence of opioids on immunomodulation using a bibliometric approach.

Methods

Articles related to opioids and immunomodulation published from 2000 to 2022 were obtained from the Science Citation Index Expanded of the Web of Science Core Collection by searching keywords related to opioids and immunomodulation. Bibliometric analyses and visualizations were conducted using the CiteSpace and VOSviewer software programs.

Results

From 2000 to 2022, a total of 3242 research articles on opioids and immunomodulation were published in 1126 academic journals by 16,555 authors in 3368 institutions from 102 countries/regions. A majority of publications were from the US and China, and the University of Minnesota System and Chinese Academy of Sciences were the most active institutions. Tsong-long Hwang had published the most papers, while Sabita Roy had the most cocitations. The Journal of Ethnopharmacology published the most papers on opioids and immunomodulation, the Journal of Immunology was the top cocited journal, and the major area of these publications were molecular, biological, and genetic. The top three keywords were "expression", "activation", and "inflammation."

Conclusion

The number of studies on opioids and immunomodulation has increased sharply all over the world in the last two decades. This is the first bibliometric study to comprehensively summarize the collaboration network in this field. It will help scholars to understand not only the basic knowledge structure but also potential collaborations, research trend topics, and hot directions.

Immunomodulatory effects of fentanyl and morphine on DSS- and TNBS-induced colitis

BACKGROUND

Opioid prescription for inflammatory bowel disease (IBD)-related pain is on the rise. However, the use of strong opioids can result in severe complications, and even death, in IBD patients. This study aimed to define the role of fentanyl and morphine, two representative strong opioids, in the pathogenesis of dextran sodium sulfate (DSS)- and 2,4,6-trinitrobenzenesulfonic acid solution (TNBS)-induced colitis.

METHOD

DSS and TNBS models were induced in C57BL/6J and Balb/c mice, respectively. Disease activity index (DAI), histopathology, enzyme-linked immunosorbent assay (ELISA), multiplex ELISA, and flow cytometry were performed to evaluate the effects of fentanyl and morphine.

RESULT

Fentanyl exacerbated DSS- and TNBS-induced colitis, while morphine exhibited no significant immunomodulatory effect. Fentanyl and morphine had no obvious effects on the serum levels of adrenocorticotropic hormone (ACTH), glucocorticoid (GC), and prostaglandin E2 (PGE-2) in DSS and TNBS models. Fentanyl elevated the proportions of Th1 cells, μ-opioid receptor (MOR) + Th1 cells, and MOR + macrophages in the colonic mucosa of DSS-treated mice, and enhanced the proportions of Th1 cells, macrophages, MOR + Th1 cells, and MOR + macrophages in the colonic mucosa of TNBS-treated mice. We found that fentanyl upregulated the levels of inflammatory cytokines/chemokines in MOR + macrophages of the colonic lamina propria mononuclear cells (LPMCs) from DSS-treated mice, whereas it had no effect on the expression of most inflammatory cytokines/chemokines in MOR + macrophages in the colonic LPMCs from TNBS-treated mice.

CONCLUSION

Our findings suggest that fentanyl exacerbates murine colitis via Th1 cell- and macrophage-mediated mechanisms, while morphine exhibits no significant immunomodulatory effect.

Effects of Esketamine Combined with Ultrasound-Guided Pectoral Nerve Block Type II on the Quality of Early Postoperative Recovery in Patients Undergoing a Modified Radical Mastectomy for Breast Cancer: A Randomized Controlled Trial

Purpose

To evaluate the effect of esketamine combined with ultrasound-guided pectoral nerve block type II (Pecs II block) on the quality of early postoperative recovery in patients undergoing a modified radical mastectomy (MRM) for breast cancer.

Patients and Methods

A total of 136 female patients undergoing an elective MRM for unilateral breast cancer (UBC) for the first time were randomly divided into the control group (group C, n=68) and the experimental group (PE group, n=68). In group C, sufentanil was used for anesthesia induction and patient-controlled intravenous analgesia (PCIA). Esketamine was used for anesthesia induction and PCIA in the PE group. Ultrasound-guided Pecs II block was performed after anesthesia induction in the two groups. All other anesthetics were administered in the same way. The primary outcome was the 40-item Quality of Recovery (QoR-40) score at discharge. The secondary outcomes were postoperative Observer’s Assessment of Alertness/Sedation Scale (OAA/S) scores, time of anesthesia recovery, Numeric Rating Scale (NRS) scores, serum inflammatory cytokines interleukin-10 (IL-10), interleukin-6 (IL-6), and interleukin-1ß (IL-1ß), Hospital Anxiety and Depression Scale (HADS) scores, length of postoperative Postanesthesia Care Unit (PACU) stay, length of postoperative hospital stay and patient satisfaction score.

Results

Compared with group C, the PE group had higher QoR-40 scores at discharge (P<0.05), decreased IL-6 levels at 24 h after surgery (P<0.05), lower anxiety and depression scores (P<0.05) and higher patient satisfaction scores at discharge (P<0.05). No significant difference was found in the NRS score postoperatively between the two groups (P>0.05). There was no significant difference in the postoperative OAA/S score, time of anesthesia recovery, length of postoperative PACU and hospital stays between the two groups (P>0.05).

Conclusion

Esketamine combined with Pecs II block can be used for anesthesia in MRM for breast cancer, thus, improving patient quality of early postoperative recovery.

Methadone use is associated with increased levels of sCD14, immune activation, and inflammation during suppressed HIV infection

Opioid use has negative effects on immune responses and may impair immune reconstitution in persons living with HIV (PLWH) infection undergoing antiretroviral treatment (ART). The effects of treatment with μ opioid receptor (MOR) agonists (e.g., methadone, MET) and antagonists (e.g., naltrexone, NTX) on immune reconstitution and immune activation in ART-suppressed PLWH have not been assessed in-depth. We studied the effects of methadone or naltrexone on measures of immune reconstitution and immune activation in a cross-sectional community cohort of 30 HIV-infected individuals receiving suppressive ART and medications for opioid use disorder (MOUD) (12 MET, 8 NTX and 10 controls). Plasma markers of inflammation and immune activation were measured using ELISA, Luminex, or Simoa. Plasma IgG glycosylation was assessed using capillary electrophoresis. Cell subsets and activation were studied using whole blood flow cytometry. Individuals in the MET group, but no in the NTX group, had higher plasma levels of inflammation and immune activation markers than controls. These markers include soluble CD14 (an independent predictor of morbidity and mortality during HIV infection), proinflammatory cytokines, and proinflammatory IgG glycans. This effect was independent of time on treatment. Our results indicate that methadone-based MOUD regimens may sustain immune activation and inflammation in ART-treated HIV-infected individuals. Our pilot study provides the foundation and rationale for future longitudinal functional studies of the impact of MOUD regimens on immune reconstitution and residual activation after ART-mediated suppression.

Emerging Paradigms in the Prevention of Surgical Site Infection: The Patient Microbiome and Antimicrobial Resistance

This article summarizes new scientific evidence on the pathogenesis of surgical site infection, including the roles of the patient microbiome and antimicrobial resistance, and reviews changes in guidelines and clinical practices for prevention.

Non-diabetic euglycaemic ketoacidosis and rapid weight loss in a post-traumatic surgical patient: is the outré preventable?

To highlight the implications of the metabolic stress response and the role of anaesthesia in attenuating its deleterious effects, we present this extremely rare case of non-diabetic euglycaemic ketoacidosis with rapid weight loss in a post-traumatic surgical patient. Ketoacidosis is the accumulation of ketone bodies in blood and is generally associated with relative or absolute insulin deficiency secondary to diabetes mellitus, sodium-glucose cotransporter 2 inhibitors and extensive fasting. The stress of systemic disease, trauma or surgery in such predisposed patients could precipitate ketoacidosis. Our patient developed high anion gap metabolic acidosis intraoperatively due to ketosis, a potentially life-threatening complication, without any predisposing factors as a result of metabolic stress of major trauma and surgery. Aiding the interpretation, he lost 15 kg weight perioperatively, suggesting his body was in a hypercatabolic state. This report emphasises the value of anaesthetic techniques to prevent such rare complications.

Opioids and cancer survival: are we looking in the wrong place?

There is a controversial narrative in the anaesthetic literature suggesting that anaesthetic technique (including opioids) may be detrimental to survival after tumour resection. The initial observations were retrospective. Several prospective studies are ongoing; one in breast cancer has reported no adverse outcome. The evidence for an effect of opioids stems from three pieces of information: (1) opioids depress the immune system, (2) opioids potentially promote angiogenesis, and (3) opioids potentially support tumour growth. Although the evidence for (2)/(3) is unclear, combinations of these effects are beneficial to tumours and potentially promote metastatic reseeding. Accepted wisdom suggests that opioid effects are driven by opioid receptor activation but the presence of opioid receptors on immune cells for example is unlikely. Immune cells, vascular endothelium and a range of tumour cells express Toll-like receptor 4 (TLR4) receptors (for Gram-negative bacterial wall components), and there is growing evidence for opioids interacting with this alternative receptor; and for some there is paradoxical naloxone sensitivity. Is the focus on opioid receptors and cancer the wrong target? TLR4 receptor activation produces immune activation, stimulates angiogenesis, and supports tumour survival. We know that some opioids are more immune suppressive than others (there is no such comparative information for angiogenesis and tumour survival); this may correlate with TLR4 activation. If there are clusters of opioids that have more opioid than TLR4 profiles and vice versa, this may influence outcome. If this is the case, then evidence-based advice could be given for perioperative use in the oncology-anaesthesia setting.

Reducing Pain in Experimental Models of Intestinal Inflammation Affects the Immune Response

The incidence of inflammatory bowel disease with its two main manifestations, colitis ulcerosa and Crohn's disease, is rising globally year after year. There is still a tremendous need to study the underlying pathomechanisms and a well-established tool in order to better understand the disease are colitis models in rodents. Since the concept of the 3Rs was proposed by Russell and Burch, this would include pain medication in animal models of intestinal inflammation as a reduction of suffering. This review argues against pain medication because the administration of pain medication in its current form has an impact on the inflammatory process and the immune response, thus falsifying the results and the reproducibility and therefore leading to misconceptions.

Opioidergic Signaling-A Neglected, Yet Potentially Important Player in Atopic Dermatitis

Atopic dermatitis (AD) is one of the most common skin diseases, the prevalence of which is especially high among children. Although our understanding about its pathogenesis has substantially grown in recent years, and hence, several novel therapeutic targets have been successfully exploited in the management of the disease, we still lack curative treatments for it. Thus, there is an unmet societal demand to identify further details of its pathogenesis to thereby pave the way for novel therapeutic approaches with favorable side effect profiles. It is commonly accepted that dysfunction of the complex cutaneous barrier plays a central role in the development of AD; therefore, the signaling pathways involved in the regulation of this quite complex process are likely to be involved in the pathogenesis of the disease and can provide novel, promising, yet unexplored therapeutic targets. Thus, in the current review, we aim to summarize the available potentially AD-relevant data regarding one such signaling pathway, namely cutaneous opioidergic signaling.

Prenatal opioid-exposed infant extracellular miRNA signature obtained at birth predicts severity of neonatal opioid withdrawal syndrome

Prenatal opioid exposure (POE) is commonly associated with neonatal opioid withdrawal syndrome (NOWS), which is characterized by a broad variability in symptoms and severity. Currently there are no diagnostic tools to reliably predict which infants will develop severe NOWS, while risk stratification would allow for proactive decisions about appropriate clinical monitoring and interventions. The aim of this prospective cohort study was to assess if extracellular microRNAs (miRNAs) in umbilical cord plasma of infants with POE could predict NOWS severity. Participants (n = 58) consisted of pregnant women receiving medications for opioid use disorder and their infants. NOWS severity was operationalized as the need for pharmacologic treatment and prolonged hospitalization (≥ 14 days). Cord blood miRNAs were assessed using semi-quantitative qRT-PCR arrays. Receiver operating characteristic curves and area under the curve (AUC) were estimated. The expression of three miRNAs (miR-128-3p, miR-30c-5p, miR-421) predicted need for pharmacologic treatment (AUC: 0.85) and prolonged hospitalization (AUC: 0.90). Predictive validity improved after two miRNAs (let-7d-5p, miR-584-5p) were added to the need for pharmacologic treatment model (AUC: 0.94) and another two miRNAs (let-7b-5p, miR-10-5p) to the prolonged hospitalization model (AUC: 0.99). Infant cord blood extracellular miRNAs can proactively identify opioid-exposed neonates at high-risk for developing severe NOWS.

Severity of neonatal opioid withdrawal syndrome with prenatal exposure to serotonin reuptake inhibitors

OBJECTIVE

To evaluate the severity of neonatal opioid withdrawal syndrome (NOWS) in infants prenatally exposed to medications for opioid use disorder (MOUD) and serotonin reuptake inhibitors (SRI).

METHODS

A prospective cohort included 148 maternal-infant pairs categorized into MOUD (n = 127) and MOUD + SRI (n = 27) groups. NOWS severity was operationalized as the infant's need for pharmacologic treatment with opioids, duration of hospitalization, and duration of treatment. The association between prenatal SRI exposure and the need for pharmacologic treatment (logistic regression), time-to-discharge, and time-to-treatment discontinuation (Cox proportional hazards modeling) was examined after adjusting for the type of maternal MOUD, use of hydroxyzine, other opioids, benzodiazepines/sedatives, alcohol, tobacco, marijuana, gestational age, and breastfeeding.

RESULTS

Infants in the MOUD + SRI group were more likely to receive pharmacologic treatment for NOWS (OR = 3.58; 95% CI: 1.31; 9.76) and had a longer hospitalization (median: 11 vs. 6 days; HR = 0.54; 95% CI: 0.33; 0.89) compared to the MOUD group. With respect to time-to-treatment discontinuation, no association was observed in infants who received treatment (HR = 0.59; 95% CI: 0.26, 1.32); however, significant differences were observed in the entire sample (HR = 0.55; 95% CI: 0.34, 0.89).

CONCLUSIONS

Use of SRIs among pregnant women on MOUD might be associated with more severe NOWS.

IMPACT

A potential drug-drug interaction between maternal SRIs and opioid medications that inhibit the reuptake of serotonin has been hypothesized but not carefully evaluated in clinical studies. Results of this prospective cohort indicate that the use of SRIs among pregnant women on MOUD is associated with more severe neonatal opioid withdrawal syndrome. This is the first prospective study which carefully examined effect modification between the type of maternal MOUD and SRI use on neonatal outcomes. This report lays the foundation for treatment optimization in pregnant women with co-occurring mental health and substance use disorders.

Influence of Deep Neuromuscular Blockade on Perioperative Stress Response in Patients Undergoing Robot-Assisted Gastrectomy: A Prospective Double-Blinded Randomized-Controlled Trial

Attenuating the intraoperative stress response is crucial; however, the effect of neuromuscular blockade (NMB) on surgical stress is not completely understood. We aimed to investigate the effects of NMB on the perioperative stress response during robot-assisted gastrectomy. Patients were assigned to the deep or moderate NMB group. Serum cortisol, prolactin, and interleukin-6 (IL-6) levels and natural killer (NK) cell percentage were measured before anesthesia induction, 90 min after pneumoperitoneum, operation end (OP_End), and postoperative day 1. Additionally, C-reactive protein (CRP) and albumin levels were estimated. Additionally, intraoperative heart rate variability was evaluated. The deep NMB group showed significantly lower levels of low-frequency/high-frequency (HF) ratio at OP_End compared to the moderate NMB group (1.4 ± 0.2 vs. 2.2 ± 0.3, respectively; Bonferroni corrected p = 0.039). Furthermore, HF power in the deep NMB group was significantly higher at OP_End than that in the moderate NMB group (45.2 ± 3.6 vs. 33.8 ± 4.0, respectively; Bonferroni corrected p = 0.044). However, no significant differences in cortisol, prolactin, IL-6, CRP, and albumin levels and NK cell percentage were found between the two groups. The degree of NMB may have similar effects on stress-related biological markers in patients undergoing robot-assisted gastrectomy.

Preemptive Intravenous Nalbuphine for the Treatment of Post-Operative Visceral Pain: A Multicenter, Double-Blind, Placebo-Controlled, Randomized Clinical Trial

INTRODUCTION

Post-operative visceral pain is common in early postoperative period after laparoscopic surgery. As a kappa opioid receptor agonist, the antinociceptive effects of nalbuphine in visceral pain are consistent across a multitude of experimental conditions irrespective of species. We hypothesized that preemptive nalbuphine can decrease the visceral pain for patients with incisional infiltration of ropivacaine after laparoscopic cholecystectomy.

METHODS

In a multicenter, prospective, double-blind, placebo-controlled, randomized clinical trial, 2094 participants scheduled for laparoscopic cholecystectomy were randomly assigned to receive nalbuphine (Nal group, n = 1029) or placebo (Con group, n = 1027). The Nal group received intravenous nalbuphine 0.2 mg·kg-1 and the Con group received saline in a similar way. The primary endpoint was the effect of nalbuphine on post-operative visceral pain intensity scores within 24 h postoperatively. The total amount of analgesic as well as complications were recorded.

RESULTS

A total of 1934 participants were analyzed. Nalbuphine reduced the visceral pain both at rest (β = - 0.1189, 95% CI - 0.23 to - 0.01, P = 0.037) and movement (β = - 0.1076, 95% CI - 0.21 to - 0.01, P = 0.040) compared with placebo. Patients in the Nal group required less frequent supplemental analgesic administration during the first 24 h after surgery. There were fewer patients in the Nal group who experienced nausea and vomiting (PONV) (P = 0.008).

CONCLUSIONS

Preemptive nalbuphine administered at a dose of 0.2 mg·kg-1 was safe and effective at reducing the postoperative visceral pain and supplemental analgesic use in patients undergoing laparoscopic cholecystectomy.

TRIAL REGISTRATION

Chinese Clinical Trial Registry; ChiCTR1800014379.

Multiple Sclerosis and the Endogenous Opioid System

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

Buprenorphine Increases HIV-1 Infection In Vitro but Does Not Reactivate HIV-1 from Latency

BACKGROUND

medication-assisted treatment (MAT) with buprenorphine is now widely prescribed to treat addiction to heroin and other illicit opioids. There is some evidence that illicit opioids enhance HIV-1 replication and accelerate AIDS pathogenesis, but the effect of buprenorphine is unknown.

METHODS

we obtained peripheral blood mononuclear cells (PBMCs) from healthy volunteers and cultured them in the presence of morphine, buprenorphine, or methadone. We infected the cells with a replication-competent CCR5-tropic HIV-1 reporter virus encoding a secreted nanoluciferase gene, and measured infection by luciferase activity in the supernatants over time. We also surveyed opioid receptor expression in PBMC, genital epithelial cells and other leukocytes by qPCR and western blotting. Reactivation from latency was assessed in J-Lat 11.1 and U1 cell lines.

RESULTS

we did not detect expression of classical opioid receptors in leukocytes, but did find nociception/orphanin FQ receptor (NOP) expression in blood and vaginal lymphocytes as well as genital epithelial cells. In PBMCs, we found that at physiological doses, morphine, and methadone had a variable or no effect on HIV infection, but buprenorphine treatment significantly increased HIV-1 infectivity (median: 8.797-fold increase with 20 nM buprenorphine, eight experiments, range: 3.570-691.9, p = 0.0078). Using latently infected cell lines, we did not detect reactivation of latent HIV following treatment with any of the opioid drugs.

CONCLUSIONS

our results suggest that buprenorphine, in contrast to morphine or methadone, increases the in vitro susceptibility of leukocytes to HIV-1 infection but has no effect on in vitro HIV reactivation. These findings contribute to our understanding how opioids, including those used for MAT, affect HIV infection and reactivation, and can help to inform the choice of MAT for people living with HIV or who are at risk of HIV infection.

Exploration of Analgesia with Tramadol in the Coxsackievirus B3 Myocarditis Mouse Model

Infection of mice with Coxsackievirus B3 (CVB3) triggers inflammation of the heart and this mouse model is commonly used to investigate underlying mechanisms and therapeutic aspects for viral myocarditis. Virus-triggered cytotoxicity and the activity of infiltrating immune cells contribute to cardiac tissue injury. In addition to cardiac manifestation, CVB3 causes cell death and inflammation in the pancreas. The resulting pancreatitis represents a severe burden and under such experimental conditions, analgesics may be supportive to improve the animals’ well-being. Notably, several known mechanisms exist by which analgesics can interfere with the immune system and thereby compromise the feasibility of the model. We set up a study aiming to improve animal welfare while ensuring model integrity and investigated how tramadol, an opioid, affects virus-induced pathogenicity and immune response in the heart. Tramadol was administered seven days prior to a CVB3 infection in C57BL/6 mice and treatment was continued until the day of analysis. Tramadol had no effect on the virus titer or viral pathogenicity in the heart tissue and the inflammatory response, a hallmark of myocardial injury, was maintained. Our results show that tramadol exerts no disruptive effects on the CVB3 myocarditis mouse model and, therefore, the demonstrated protocol should be considered as a general analgesic strategy for CVB3 infection.

Association between preoperative administration of gabapentinoids and 30-day hospital readmission: A retrospective hospital registry study

STUDY OBJECTIVE

To evaluate the effectiveness of preoperative gabapentinoid administration.

DESIGN

Retrospective hospital registry study.

SETTING

Tertiary referral center (Boston, MA).

PATIENTS

111,008 adult non-emergency, non-cardiac surgical patients between 2014 and 2018.

INTERVENTIONS

Preoperative administration of gabapentinoids (gabapentin or pregabalin).

MEASUREMENTS

We tested the primary hypothesis that preoperative gabapentinoid use was associated with lower odds of hospital readmission within 30 days. Contingent on this hypothesis, we examined whether lower intraoperative opioid utilization mediated this effect. Secondary outcome was postoperative respiratory complications.

MAIN RESULTS

Gabapentinoid administration was associated with lower odds of readmission (adjusted odds ratio [OR_adj] 0.80 [95% CI, 0.75-0.85]; p < 0.001). This effect was in part mediated by lower intraoperative opioid utilization in patients receiving gabapentinoids (8.2% [2.4-11.5%]; p = 0.012). Readmissions for gastrointestinal disorders (OR_adj 0.74 [0.60-0.90]; p = 0.003), neuro-psychiatric complications (OR_adj 0.66 [0.49-0.87]; p = 0.004), non-surgical site infections (OR_adj 0.68 [0.52-0.88; p = 0.004) and trauma or poisoning (OR_adj 0.25 [0.16-0.41]; p < 0.001) occurred less frequently in patients receiving gabapentinoids. The risk of postoperative respiratory complications was lower in patients receiving gabapentinoids (OR_adj 0.77 [0.70-0.85]; p < 0.001). Lower doses of pregabalin (< 75 mg) and gabapentin (< 300 mg) compared to both, no and high-dose administration of gabapentinoids, were associated with a lower risk of postoperative respiratory complications (OR_adj 0.61 [0.50-0.75]; p < 0.001 and OR_adj 0.70 [0.53-0.92]; p = 0.012, respectively). These lower gabapentinoid doses prevented 30-day readmission (OR_adj 0.74 [0.65-0.85]; p < 0.001). The results were robust in several sensitivity analyses including surgical procedure defined subgroups and patients undergoing ambulatory surgery.

CONCLUSIONS

The preoperative use of pregabalin and gabapentin, up to doses of 75 and 300 mg respectively, mitigates the risks of hospital readmission and postoperative respiratory complications which can in part be explained by lower intraoperative opioid use. Further research is warranted to elucidate mechanisms of the preventive action.

Immunomodulators in anesthesia

PURPOSE OF REVIEW

Anesthetics are known to have immunomodulatory effects. These can be detrimental, inducing immunosuppression and facilitating the development of opportunistic infections, especially when used at high doses, for prolonged periods, or in patients with preexisting immune deficiency; or beneficial, modulating the inflammatory response, particularly in critical illness and systemic hyperinflammatory states.

RECENT FINDINGS

Anesthetics can have microbicidal properties, and both anti- and pro-inflammatory effects. They can act directly on immune cells as well as modulate immunity through indirect pathways, acting on the neuroimmune stress response, and have recently been described to interact with the gut microbiota.

SUMMARY

Anesthesiologists should take into consideration the immunomodulatory properties of anesthetic agents in addition to their hemodynamic, neuroprotective, and other impacts. In future, patient stratification according to the perioperative assessment of serum biomarkers associated with postoperative complications may be used to guide anesthetic agent selection based on their immunomodulatory properties.

The self-serving benefits of being a good host: A role for our micro-inhabitants in shaping opioids' function

Opioids are highly efficacious in their ability to relieve pain, but they are liable for abuse, dependence, and addiction. Risk factors to develop opioid use disorders (OUD) include chronic stress, socio-environment, and preexisting major depressive disorders (MDD) and posttraumatic stress disorders (PTSD). Additionally, opioids reduce gut motility, induce loss of gut barrier function, and alter the composition of the trillions of microbes hosted in the gastrointestinal tract, known as the gut microbiota. The microbiota are significant contributors to the reciprocal communication between the central nervous system (CNS) and the gut, termed the gut-brain axis. They have strong influences on their host behaviors, including the ability to cope with stress, sociability, affect, mood, and anxiety. Thus, they are implicated in the etiology of MDD and PTSD. Here we review the latest studies demonstrating that intestinal flora can, directly and indirectly, by affecting sociability levels, responses to stress, and mental state, alter the responses to opioids. It suggests that microbiota can potentially be used to increase the resilience to develop analgesic tolerance and OUD.

Comparative Efficacy of Fentanyl and Morphine in Patients with or At Risk for Acute Respiratory Distress Syndrome: A Propensity Score-Matched Cohort Study

Introduction

Opioids are potent painkillers but can have severe adverse effects in the intensive care unit (ICU). The aim of this study was to compare the outcomes of fentanyl and morphine use among patients at risk for and with acute respiratory distress syndrome (ARDS).

Methods

We developed a dataset of real-world data to enable the comparison of the effectiveness and safety of opioids and the associated outcomes from the Multiparameter Intelligent Monitoring in Intensive Care (MIMIC)-III database and the eICU Collaborative Research Database. Patients who were admitted to the ICU with a diagnosis of or at risk for ARDS and received mechanical ventilation for at least 12 h were included. Patients were enrolled sequentially into one of six groups in three cohorts: treated with fentanyl or not; treated with morphine or not; and treated with fentanyl or morphine. Propensity score matching and multivariable analyses were performed.

Results

Fentanyl was associated with higher in-hospital mortality in the propensity score-matched model but not in the linear regression model. The use of morphine was associated with a higher in-hospital mortality in both models. Both fentanyl and morphine were associated with longer duration of mechanical ventilation, ICU stay, and hospitalization and a decreased likelihood of being discharged home in both models. Notably, compared with morphine, fentanyl was associated with a lower mortality and an increased likelihood of being discharged home.

Conclusions

Both fentanyl and morphine were independent risk factors for worse outcomes in patients with or at risk for ARDS. Compared with morphine, fentanyl may be preferred in these patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40268-021-00338-3.

Opioids and premature biochemical recurrence of prostate cancer: a randomised prospective clinical trial

BACKGROUND

Prostate cancer is one of the most prevalent neoplasms in male patients, and surgery is the main treatment. Opioids can have immune modulating effects, but their relation to cancer recurrence is unclear. We evaluated whether opioids used during prostatectomy can affect biochemical recurrence-free survival.

METHODS

We randomised 146 patients with prostate cancer scheduled for prostatectomy into opioid-free anaesthesia or opioid-based anaesthesia groups. Baseline characteristics, perioperative data, and level of prostate-specific antigen every 6 months for 2 yr after surgery were recorded. Prostate-specific antigen >0.2 ng ml^-1 was considered biochemical recurrence. A survival analysis compared time with biochemical recurrence between the groups, and a Cox regression was modelled to evaluate which variables affect biochemical recurrence-free survival.

RESULTS

We observed 31 biochemical recurrence events: 17 in the opioid-free anaesthesia group and 14 in the opioid-based anaesthesia group. Biochemical recurrence-free survival was not statistically different between groups (P=0.54). Cox regression revealed that biochemical recurrence-free survival was shorter in cases of obesity (hazard ratio [HR] 1.63, confidence interval [CI] 0.16-3.10; p=0.03), high D'Amico risk (HR 1.58, CI 0.35-2.81; P=0.012), laparoscopic surgery (HR 1.6, CI 0.38-2.84; P=0.01), stage 3 tumour pathology (HR 1.60, CI 0.20-299) and N1 status (HR 1.34, CI 0.28-2.41), and positive surgical margins (HR 1.37, CI 0.50-2.24; P=0.002). The anaesthesia technique did not affect time to biochemical recurrence (HR -1.03, CI -2.65-0.49; P=0.18).

CONCLUSIONS

Intraoperative opioid use did not modify biochemical recurrence rates and biochemical recurrence-free survival in patients with intermediate and high D'Amico risk prostate cancer undergoing radical prostatectomy.

CLINICAL TRIAL REGISTRATION

NCT03212456.

The Reasons for Higher Mortality Rate in Opium Addicted Patients with COVID-19: A Narrative Review

The outbreak of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) caused COVID-19 has developed into an unexampled worldwide pandemic. The most important cause of death in patients with COVID-19 is Acute Respiratory Distress Syndrome (ARDS). Opium is widely used for its analgesic features in control of acute and chronic pain related to different diseases. Opium consumption is increased over the last three decades and leads to adverse effects on the respiratory system; opium also affects the lungs' functions and respiration. The contemplative issue is the higher mortality rate due to SARS-CoV-2 infection in opium addicts' patients. Studies have shown that despite the decrease in proinflammatory cytokines production in opium addicts, there are at least 4 reasons for this increase in mortality rate: downregulation of IFNs expression, development of pulmonary edema, increase thrombotic factors, increase the expression of Angiotensin-converting enzyme 2 (ACE2). Therefore, identifying the causes of mortality and approved therapies for the treatment of COVID-19 patients who use opium for any reason is an important unmet need to reduce SARS-CoV-2 infection-related mortality. This review study demonstrated the effects of opium on immune responses and the reasons for the higher mortality rate in opium addicts' patients with COVID-19.

Nalfurafine reduces neuroinflammation and drives remyelination in models of CNS demyelinating disease

Objectives

Multiple sclerosis (MS) is a neurodegenerative disease characterised by inflammation and damage to the myelin sheath, resulting in physical and cognitive disability. There is currently no cure for MS, and finding effective treatments to prevent disease progression has been challenging. Recent evidence suggests that activating kappa opioid receptors (KOR) has a beneficial effect on the progression of MS. Although many KOR agonists like U50,488 are not suitable for clinical use because of a poor side‐effect profile, nalfurafine is a potent, clinically used KOR agonist with a favorable side‐effect profile.

Methods

Using the experimental autoimmune encephalomyelitis (EAE) model, the effect of therapeutically administered nalfurafine or U50,488 on remyelination, CNS infiltration and peripheral immune responses were compared. Additionally, the cuprizone model was used to compare the effects on non‐immune demyelination.

Results

Nalfurafine enabled recovery and remyelination during EAE. Additionally, it was more effective than U50,488 and promoted disease reduction when administered after chronic demyelination. Blocking KOR with the antagonist, nor‐BNI, impaired full recovery by nalfurafine, indicating that nalfurafine mediates recovery from EAE in a KOR‐dependent fashion. Furthermore, nalfurafine treatment reduced CNS infiltration (especially CD4⁺ and CD8⁺ T cells) and promoted a more immunoregulatory environment by decreasing Th17 responses. Finally, nalfurafine was able to promote remyelination in the cuprizone demyelination model, supporting the direct effect on remyelination in the absence of peripheral immune cell invasion.

Conclusions

Overall, our findings support the potential of nalfurafine to promote recovery and remyelination and highlight its promise for clinical use in MS.

A Critical Appraisal of the Effects of Anesthetics on Immune-system Modulation in Critically Ill Patients With COVID-19

Purpose

The aim of the present article was to briefly summarize current knowledge about the immunomodulatory effects of general anesthetics and the possible clinical effects of this immunomodulation in patients with COVID-19.

Methods

The PubMed, Scopus, and Google Scholar databases were comprehensively searched for relevant studies.

Findings

The novel coronavirus causes a wide spectrum of clinical manifestations, with a large absolute number of patients experiencing severe pneumonia and rapid progression to acute respiratory distress syndrome and multiple organ failure. In these patients, the equilibrium of the inflammatory response is a major determinant of survival. The impact of anesthetics on immune-system modulation may vary and includes both pro-inflammatory and anti-inflammatory effects.

Implications

Inhibition of the development of severe inflammation and/or the enhancement of inflammation resolution by anesthetics may limit organ damage and improve outcomes in patients with COVID-19.

Unhealthy Opioid Use and COVID-19 Mortality Incidence in Older Adults: A Multicenter Research Network Study

Opioid use has the potential to influence infectious respiratory diseases. The purpose of this research is to examine if there is an association of deaths from the respiratory infection, COVID-19, and unhealthy opioid use in older adults. Data about patients, ages ≥65 years, who had a COVID-19 infection between 1/20/2020 to 12/23/2020 (n = 533,153) were extracted using the TriNetX system. Mortality incidence between initial diagnosis and ninety days after contracting COVID-19 were determined. Comparisons were made between people with and without unhealthy opioid use. There were 7,547 COVID-19 patients with unhealthy opioid use (mean age, 71.8 years; standard deviation 6.3 years) and 525,606 COVID-19 patients (mean age, 74.1 years; standard deviation 7.3 years) without unhealthy opioid use. Of the total, 15,852 (3.0%) died within 3 months of COVID-19 diagnosis. The unadjusted risk ratio of the cohort with unhealthy opioid use compared with the cohort that did not have unhealthy opioid uses was 1.18 (95% CI: 1.05,1.33); p = 0.0069. The relationship failed to remain significant in analysis with propensity score matching (risk ratio = 0.96; 95% CI: 0.82, 1.14; p = 0.6606, ns). The public health implication is that although older adults are more vulnerable to COVID-19 than younger adults, a difference between older adults with or without unhealthy opioid use did not increase vulnerability to death from COVID-19 and should be not be considered if rationing of care becomes necessary.

Impact of anesthesia methods on perioperative systemic inflammation and long-term outcomes in patients undergoing surgery for hepatocellular carcinoma: a propensity score-matched analysis

Background

Recent studies have shown regional anesthesia might improve the survival of cancer patients. We hypothesized that general-epidural anesthesia (GEA) was associated with longer survival than general anesthesia (GA) in patients undergoing hepatocellular carcinoma (HCC) resections.

Methods

A retrospective study included patients who received curative resection for HCC between January 2014 to December 2017. Patients were grouped in GEA vs. GA. After propensity score matching, perioperative inflammatory scores were calculated. Grade of postoperative complications, length of stay (LOS), dosage of sufentanil used and times of patients requiring rescue analgesia in both groups were compared for intraoperative and postoperative parameter. Survival curves were constructed from the date of surgery to death, univariable and multivariable Cox regression models were used to compare hazard ratios for death.

Results

A total of 772 patients were included in the study. With 386 patients in GA group and 386 patients in GEA group. After propensity score matching, the demographic and baseline biomarkers in the two groups were similar. Patients in GEA group showed significantly lower inflammatory scores. Grade of postoperative complications, LOS, opioid use, and times of patients requiring rescue analgesia was significantly lower in the GEA group. The overall survival (OS) and disease-free survival (DFS) rate was significantly lower in the GA group (54.2% vs. 62.3%, 41.2% vs. 52.5%, P<0.001). The multivariate analysis indicated the GA was associated with shorter OS (HR: 1.28, 95% CI: 1.07–2.02, P<0.001) and DFS (HR: 1.06, 95% CI: 1.03–1.71, P<0.001).

Conclusions

GA combined with epidural anesthesia is associated with lower levels of inflammation, and longer survival in patients undergoing hepatectomy.

Expression of Opioid Receptors in Cells of the Immune System

The observation of the immunomodulatory effects of opioid drugs opened the discussion about possible mechanisms of action and led researchers to consider the presence of opioid receptors (OR) in cells of the immune system. To date, numerous studies analyzing the expression of OR subtypes in animal and human immune cells have been performed. Some of them confirmed the expression of OR at both the mRNA and protein level, while others did not detect the receptor mRNA either. Although this topic remains controversial, further studies are constantly being published. The most recent articles suggested that the expression level of OR in human peripheral blood lymphocytes could help to evaluate the success of methadone maintenance therapy in former opioid addicts, or could serve as a biomarker for chronic pain diagnosis. However, the applicability of these findings to clinical practice needs to be verified by further investigations.

A double-edged sword of using opioids and COVID-19: a toxicological view

Today, COVID-19 is spreading around the world. Information about its mechanism, prognostic factors, and management is minimal. COVID-19, as a human disease, has several identifying phases. Physicians of patients with COVID-19 may be interested in knowing whether opioid use disorder may affect their patients' course or prognosis. This information may be crucial when considering the opioid epidemic in the US and other parts of the world. Opioid use at high doses and over several months duration can mitigate the immune system's function, which may complicate the course of COVID-19 disease. Potential suppression of parts of the immune response may be important in prevention, clinical support, and therapeutic use of medications in various phases of the COVID-19. Specifically, opioid use disorders via an inhalation route may enhance the "late hyper-inflammatory phase" or result in end-organ damage. It is well established that opioids decrease ventilation as their effect on the medullary respiratory centers increases the risk of pneumonia. This increased risk has been associated with immune-suppressive opioids. The ultimate role of opioids in COVID-19 is not clear. This paper endorses the need for clinical studies to decipher the role and impact of chronic opioid use on viral diseases such as COVID-19.

Unintended Effects of GPCR-Targeted Drugs on the Cancer Phenotype

G protein-coupled receptors (GPCRs) are the most common class of therapeutic targets, accounting for ~35% of all FDA-approved drugs. Cancer patients receive numerous medications not only to combat cancer but also to alleviate pain, nausea, and anxiety, many of which target GPCRs. Emerging evidence has implicated GPCRs as drivers of cancer progression, therapeutic resistance, and metastasis. Therefore, the effects of commonly prescribed GPCR-targeted drugs must be reevaluated in the context of cancer. Epidemiological and experimental evidence indicate that widely used GPCR-targeted drugs may promote or inhibit cancer progression. It is crucial that we more fully understand the indirect effects of GPCR-targeted drugs on the cancer phenotype. This review summarizes recent advances in characterizing these interactions and highlights future research opportunities.

Opioid-Induced Immunomodulation: Consequences for the Experimental Coxsackievirus B3-Induced Myocarditis Model

Simple Summary

Myocarditis is an inflammatory disorder of the heart mainly caused by viruses. To investigate viral myocarditis, the Coxsackievirus B3 (CVB3)-induced myocarditis model is the experimental model used since more than sixty years. In the pathogeneses of viral myocarditis, the subtle balance between pro-and anti-inflammatory immune responses is of great importance for disease manifestation. Parallel to the infection of the heart, experimental CVB3-induced myocarditis results in an infection of the pancreas, causing a severe burden for the challenged animals. In frame of animal welfare, application of analgesics is mandatory. So far, positive as well as negative effects of opioids on the immune system have been described. However, the impact of opioid application on the pathogenesis of experimental CVB3-induced myocarditis has not been investigated yet. Since examinations on disease pathways and new treatment options rely on established models to generate reproducible data, applicability of opioids in experimental CVB3-induced myocarditis needs to be carefully evaluated. For this purpose, we summarized published studies for 13 different opioids and discussed their potential impact on the CVB3-induced myocarditis model.

Abstract

Myocarditis is an inflammatory disorder of the heart predominantly caused by infectious agents. Since more than sixty years, the Coxsackievirus B3 (CVB3)-induced myocarditis mouse model is the experimental model used to investigate viral myocarditis. The pathogenesis of viral myocarditis is conceptually a multiphase process, initiated by the infection of cardiomyocytes, followed by activation of the immune system, and resulting in myocardial fibrosis and left ventricular dysfunction. In parallel to the direct infection of the heart, CVB3 replicates in lymphatic organs such as the pancreas. Due to infection of the pancreas, the model of experimental CVB3-induced myocarditis is estimated as a severe burden for the challenged animals. Application of analgesics in frame of the animal welfare act (European directive 2010/63/EU) is more and more becoming a matter of debate. For this purpose, we summarized published studies for 13 different opioids and discussed their potential impact on CVB3-induced myocarditis. In addition, with this summary we also want to provide guidance for researchers beyond the myocarditis field to estimate the impact of opioids on the immune system for their specific model. In the literature, both immunosuppressive as well as immune-activating effects of opioids have been described, but examinations in experimental CVB3-induced myocarditis have still not been reported so far. Based on the existing publications, administration of opioids in experimental CVB3-induced myocarditis might result in more severe disease progression, including higher mortality, or a less pronounced myocarditis model, failing to be used for the establishment of new treatment options. Taken together, the applicability of opioids in experimental CVB3-induced myocarditis and in inflammatory models in general needs to be carefully evaluated and further investigated.

Effect of Opioid Use on Immune Activation and HIV Persistence on ART

While there is an emerging consensus that engagement of the Mu opioid receptor by opioids may modulate various stages the HIV life cycle (e.g.: increasing cell susceptibility to infection, promoting viral transcription, and depressing immune responses to virally-infected cells), the overall effect on latency and viral reservoirs remains unclear. Importantly, the hypothesis that the increase in immune activation observed in chronic opioid users by direct or indirect mechanisms (i.e., microbial translocation) would lead to a larger HIV reservoir after ART-suppression has not been supported to date. The potential for a subsequent decrease in reservoirs after ART-suppression has been postulated and is supported by early reports of opioid users having lower latent HIV burden. Here, we review experimental data supporting the link between opioid use and HIV modulation, as well as the scientific premise for expecting differential changes in immune activation and HIV reservoir between different medications for opioid use disorder. A better understanding of potential changes in HIV reservoirs relative to the engagement of the Mu opioid receptor and ART-mediated immune reconstitution will help guide future cure-directed studies in persons living with HIV and opioid use disorder. Graphical Abstract Review. HIV replication, immune activation and dysbiosis: opioids may affect immune reconstitution outcomes despite viral suppression.

Pain management with opioids in adults

Given the ubiquitous nature of opioids in the treatment of pain, it is an interesting paradox that this class of medications also represents one of the least understood components of clinical pain medicine. For many years, there has been intense interest in the mechanisms of opioid activity, but this has not resulted in a corresponding increase in convincing clinical data. This review focuses primarily on the evidence surrounding the long-term use of opioids in chronic pain, but discussions of this research are often conflated with the very different data governing acute and cancer-related pain, where evidence of efficacy is clearer. It is therefore important to clarify the evidence-based indications for opioid therapy. There remains very little evidence that opioids improve function or quality of life beyond 3 months in people with chronic pain conditions. In all three patient populations, the development of tolerance, dependence, hyperalgesia and withdrawal are key phenomena that affect the patient experience, and in particular the decision to remain on opioids in the long term. This is a common thread that connects the opioid literature in all of these spheres, and justifies the burgeoning interest in these phenomena in the basic science literature. There is an urgent need to address these negative consequences of opioid use, in order to maximize the therapeutic benefit that opioids can offer.