The Role of Opioid Receptors in Immune System Function

Opioid-free anesthesia reduces the severity of acute postoperative motion-induced pain and patient-controlled epidural analgesia-related adverse events in lung surgery: randomized clinical trial

Background

Opioids have been used as pain relievers for thousands of years. However, they may also cause undesirable side effects. We therefore performed this study to compare the effect of opioid-free anesthesia (OFA) versus opioid-sparing anesthesia (OSA) on postoperative pain and patient-controlled epidural analgesia (PCEA)-related events.

Methods

This is a single center randomized clinical trial that was recruited patients aged from 18 to 70 years who received video-assisted lung surgery between October 2021 and February 2022. Participants were 1:1 randomly assigned to OFA or OSA. Patients in the OFA group received propofol, rocuronium, esmolol, lidocaine, and magnesium sulfate intravenously with epidural ropivacaine. Patients in the OSA group received propofol, rocuronium, remifentanil, and sufentanil intravenously with epidural hydromorphone and ropivacaine.

Results

A total number of 124 patients were randomly allocated to the OFA or OSA group. In the OFA group, the severity of pain during coughs on the first postoperative days (PODs; VAS score 1.88 ± 0.88 vs. 2.16 ± 1.1, p = 0.044) was significantly lower than that in the OSA group. The total ratio of PCEA-related adverse events in the OFA group [11 (19.6%) vs. 26 (47.3%), p = 0.003] was significantly lower than in the OSA group.

Conclusion

OFA in patients who received video-assisted lung surgery led to lower severity of acute postoperative motion-induced pain and fewer PCEA-related adverse events on the first POD than in the patients in the OSA group.

Clinical trial registration

clinicaltrials.gov, identifier (NCT05063396).

Low-dose naltrexone use for the management of post-acute sequelae of COVID-19

The global prevalence of Post-Acute Sequelae of SARS-CoV-2 Infection (PASC) stands at approximately 43 % among individuals who have previously had acute COVID-19. In contrast, in the United States, the National Center for Health Statistics (NCHS) estimates that around 11 % of individuals who have been infected with SARS-CoV-2 go on to experience long COVID. The underlying causes of PASC remains under investigation, and there are no currently established FDA-approved therapies. One of the leading hypotheses for the cause of PASC is the persistent activation of innate immune cells with increase systemic inflammation. Naltrexone is a medication with anti-inflammatory and immunomodulatory properties that has been used in other conditions that overlap with PASC. We performed a retrospective review of a clinical cohort of 59 patients at a single academic center who received low-dose naltrexone (LDN) off-label as a potential therapeutic intervention for PASC. The use of LDN was associated with a fewer number of symptoms, improved clinical symptoms (fatigue, post-exertional malaise, unrefreshing sleep, and abnormal sleep pattern), and a better functional status. This observation warrants testing in rigorous, randomized, placebo-controlled clinical trials.

The tumor microenvironment in the postsurgical liver: Mechanisms and potential targets of postoperative recurrence in human hepatocellular carcinoma

Surgery remains to be the mainstay of treatment for hepatocellular carcinoma (HCC). Nonetheless, its therapeutic efficacy is significantly impaired by postoperative recurrence, which occurs in more than half of cases as a result of intrahepatic metastasis or de novo tumorigenesis. For decades, most therapeutic strategies on inhibiting postoperative HCC recurrence have been focused on the residual tumor cells but satisfying therapeutic outcomes are barely observed in the clinic. In recent years, a better understanding of tumor biology allows us to shift our focus from tumor cells toward the postoperative tumor microenvironment (TME), which is gradually identified to play a pivotal role in tumor recurrence. In this review, we describe various surgical stress and surgical perturbation on postoperative TME. Besides, we discuss how such alternations in TME give rise to postoperative recurrence of HCC. Based on its clinical significance, we additionally highlight the potential of the postoperative TME as a target for postoperative adjuvant therapeutics.

The effect of chronic stress on the immunogenicity and immunoprotection of the M6-TT vaccine in female mice

Active vaccination is an effective therapeutic option to reduce the reinforcing effects of opioids. Several studies showed that chronic stress affects the immune system decreasing the efficiency of some vaccines. Heroin withdrawal is a stressor and it is a stage in which the patient who abuses heroin is vulnerable to stress affects the immune response and consequently its immunoprotective capacity, then, the objective was to determine the effect of heroin-withdrawal and heroin-withdrawal plus immobilization, on the immune (immunogenicity) and protective response (behavioral response) of morphine-6-hemisuccinate-tetanus toxoid (M6-TT) vaccine in animals of two inbred mice strains with different sensitivity to drug-opioid and stress. Female BALB/c and C57Bl/6 inbred mice were immunized with the M6-TT. A solid-phase antibody-capture ELISA was used to monitor antibody titer responses after each booster dose in vaccinated animals. During the vaccination period, the animals were subjected to two different stress conditions: drug-withdrawal (DW) and immobilization (IMM). The study used tail-flick testing to evaluate the heroin-induced antinociceptive effects. Additionally, heroin-induced locomotor activity was evaluated. Stress decreased the heroin-specific antibody titer generated by the M6-TT vaccine in the two inbred mouse strains evaluated. In the two stress conditions, the antibody titer was not able to decrease the heroin-induced antinociceptive effects and locomotor activity. These findings suggest that stress decreases the production of antibodies and the immunoprotective capacity of the M6-TT vaccine. This observation is important to determine the efficacy of active vaccination as a potential therapy for patients with opioid drug use disorder, since these patients during drug-withdrawal present stress disorders, which could affect the efficacy of therapy such as active vaccination.

Neuroimmune Mechanisms of Opioid Use Disorder and Recovery: Translatability to Human Studies, and Future Research Directions

Opioid use disorder (OUD) is a major current cause of morbidity and mortality. Long-term exposure to short-acting opioids (MOP-r agonists such as heroin or fentanyl) results in complex pathophysiological changes to neuroimmune and neuroinflammatory functions, affected in part by peripheral mechanisms (e.g., cytokines in blood), and by neuroendocrine systems such as the hypothalamic-pituitary-adrenal (HPA) stress axis. There are important findings from preclinical models, but their role in the trajectory and outcomes of OUD in humans is not well understood. The goal of this narrative review is to examine available data on immune and inflammatory functions in persons with OUD, and to identify major areas for future research. Peripheral blood biomarker studies revealed a pro-inflammatory state in persons with OUD in withdrawal or early abstinence, consistent with available postmortem brain studies (which show glial activation) and diffusion tensor imaging studies (indicating white matter disruptions), with gradual abstinence-associated recovery. The mechanistic roles of these neuroimmune and neuroinflammatory changes in the trajectory of OUD (including recovery and medication management) cannot be examined practically with postmortem data. Collection of longitudinal data in larger-scale human cohorts would allow examination of these mechanisms associated with OUD stage and progression. Given the heterogeneity in presentation of OUD, a precision medicine approach integrating multi-omic peripheral biomarkers and comprehensive phenotyping, including neuroimaging, can be beneficial in risk stratification, and individually optimized selection of interventions for individuals who will benefit, and assessments under refractory therapy.

Single nucleus transcriptomics of ventral midbrain identifies glial activation associated with chronic opioid use disorder

Dynamic interactions of neurons and glia in the ventral midbrain mediate reward and addiction behavior. We studied gene expression in 212,713 ventral midbrain single nuclei from 95 individuals with history of opioid misuse, and individuals without drug exposure. Chronic exposure to opioids was not associated with change in proportions of glial and neuronal subtypes, however glial transcriptomes were broadly altered, involving 9.5 - 6.2% of expressed genes within microglia, oligodendrocytes, and astrocytes. Genes associated with activation of the immune response including interferon, NFkB signaling, and cell motility pathways were upregulated, contrasting with down-regulated expression of synaptic signaling and plasticity genes in ventral midbrain non-dopaminergic neurons. Ventral midbrain transcriptomic reprogramming in the context of chronic opioid exposure included 325 genes that previous genome-wide studies had linked to risk of substance use traits in the broader population, thereby pointing to heritable risk architectures in the genomic organization of the brain's reward circuitry.

In vitro sepsis up-regulates Nociceptin/Orphanin FQ receptor expression and function on human T- but not B-cells

BACKGROUND AND PURPOSE

In animal models of sepsis, increased activation of the Nociceptin/Orphanin FQ (N/OFQ) receptor NOP is associated with mortality and NOP antagonists improved survival. We have explored the role of the N/OFQ-NOP system in freshly isolated volunteer human B- and T-cells incubated with lipopolysaccharide (LPS) and peptidoglycan G (PepG) as a model of in vitro sepsis.

EXPERIMENTAL APPROACH

B- and T-cell NOP expression was measured using the NOP fluorescent probe N/OFQATTO594 , N/OFQ content was measured using immunofluorescence, N/OFQ release was tracked using a CHOhNOPGαiq5 biosensor assay and NOP function was measured using transwell migration and cytokine/chemokine release using a 25-plex assay format. Cells were challenged with LPS/PepG.

KEY RESULTS

CD19-positive B-cells bound N/OFQATTO594 ; they also contain N/OFQ. Stimulation with CXCL13/IL-4 increased N/OFQ release. N/OFQ trended to reduced migration to CXCL13/IL-4. Surface NOP expression was unaffected by LPS/PepG, but this treatment increased GM-CSF release in an N/OFQ sensitive manner. CD3-positive T-cells did not bind N/OFQATTO594 ; they did contain N/OFQ. Stimulation with CXCL12/IL-6 increased N/OFQ release. When incubated with LPS/PepG, NOP surface expression was induced leading to N/OFQATTO594 binding. In LPS/PepG-treated cells, N/OFQ reduced migration to CXCL12/IL-6. LPS/PepG increased GM-CSF release in an N/OFQ sensitive manner.

CONCLUSIONS AND IMPLICATIONS

We suggest both a constitutive and sepsis-inducible N/OFQ-NOP receptor autocrine regulation of B- and T-cell function, respectively. These NOP receptors variably inhibit migration and reduce GM-CSF release. These data provide mechanistic insights to the detrimental role for increased N/OFQ signalling in sepsis and suggest a potential role for NOP antagonists as treatments.

Microglial inflammation modulates opioid analgesic tolerance

As we all know, opioids are the drugs of choice for treating severe pain. However, very often, opioid use leads to tolerance, dependence, and hyperalgesia. Therefore, understanding the mechanisms underlying opioid tolerance and designing strategies for increasing the efficacy of opioids in chronic pain are important areas of research. Microglia are brain macrophages that remove debris and dead cells from the brain and participate in immune defense of the central nervous system during an insult or injury. However, recent studies indicate that microglial activation and generation of proinflammatory molecules (e.g., cytokines, nitric oxide, eicosanoids, etc.) in the brain may contribute to opioid tolerance and other side effects of opioid use. In this review, we will summarize the evidence and possible mechanisms by which proinflammatory molecules produced by activated microglia may antagonize the analgesic effect induced by opioids, and thus, lead to opioid tolerance. We will also delineate specific examples of studies that suggest therapeutic targets to counteract the development of tolerance clinically using suppressors of microglial inflammation.

Targeting Opioid Receptors in Addiction and Drug Withdrawal: Where Are We Going?

This review article offers an outlook on the use of opioids as therapeutics for treating several diseases, including cancer and non-cancer pain, and focuses the analysis on the opportunity to target opioid receptors for treating opioid use disorder (OUD), drug withdrawal, and addiction. Unfortunately, as has been well established, the use of opioids presents a plethora of side effects, such as tolerance and physical and physiological dependence. Accordingly, considering the great pharmacological potential in targeting opioid receptors, the identification of opioid receptor ligands devoid of most of the adverse effects exhibited by current therapeutic agents is highly necessary. To this end, herein, we analyze some interesting molecules that could potentially be useful for treating OUD, with an in-depth analysis regarding in vivo studies and clinical trials.

Effects of the Co-Administration of Morphine and Lipopolysaccharide on Toll-Like Receptor-4/Nuclear Factor Kappa β Signaling Pathway of MDA-MB-231 Breast Cancer Cells

Background

The Toll-like receptor 4 (TLR4) gene promotes migration in adenocarcinoma cells. Morphine is an agonist for TLR4 that has a dual role in cancer development. The promoter or inhibitor role of morphine in cancer progression remains controversial. This study aims to evaluate the effects of morphine on the TLR4, myeloid differentiation primary response protein 88-dependent (MyD88), and nuclear factor-kappa B (NF-κB) expressions in the human MDA-MB-231 breast cancer cell line.

Materials and Methods

The cells were examined after 24 hours of incubation with morphine using the Boyden chamber system. TLR4, MyD88, and NF-κB mRNA expressions were assessed using quantitative real-time polymerase chain reaction (RT-PCR). The concentration of interleukin-2 beta was also measured using the ELISA assay.

Results

According to the findings, three doses of morphine (0.25, 1.25, and 0.025 μM) increased the expression of the TLR4 and NF-κB genes, whereas no significant change was observed in the mRNA expression of MyD88. Furthermore, treatment with morphine and lipopolysaccharide (LPS) significantly decreased the expression of TLR4, MyD88, and NF-κB. However, no significant change was observed in interleukin 2 beta concentration.

Conclusions

These findings confirmed the excitatory effects of morphine on TRL4 expression and the MYD88 signaling pathway in vitro.

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.

Effects of Morphine on Gp120-induced Neuroinflammation Under Immunocompetent Vs. Immunodeficient Conditions

HIV-associated neurocognitive disorder (HAND) is a common complication of HIV infection, whose development is known to be facilitated by inflammation and exacerbated by morphine. Previously, using the gp120 transgenic (tg) mouse model in combination with LP-BM5 (a murine retrovirus that can cause systemic immunodeficiency in susceptible mouse strains) we demonstrated differential gp120-associated central nervous system (CNS) neuroinflammatory responses under immunocompetent (-LP-BM5) vs. immunocompromised (+LP-BM5) conditions. Here, we further investigated the effects of morphine on gp120-associated neuroinflammatory response within the hippocampus under differential immune status. First, we confirmed that morphine treatment (2 × 25 mg pellets) did not significantly affect the development of immunodeficiency induced by LP-BM5 and all brain regions examined (hippocampus, striatum, and frontal lobe) had detectable LP-BM5 viral gag genes. Morphine notably reduced the performance of gp120tg+ mice in the alteration T-maze assay when 2-minute retention was used, regardless of LP-BM5 treatment. Morphine further enhanced GFAP expression in gp120tg+ mice regardless of host immune status, while promoted CD11b expression only in immunocompetent mice, regardless of gp120tg expression. In immunocompetent gp120tg+ mice, morphine increased the RNA expression of CCL2, CCL5, CXCL10, IL-12p40, and IFNβ; while under the immunodeficient condition, morphine downregulated the expression of CCL2, CCL5, CXCL10, IL-12p40, and IL-1β. Further, expression of TNFα and IFNγ were enhanced by morphine regardless of host immune status. Altogether, our results suggest that the effects of morphine are complex and dependent on the immune status of the host, and host immune status-specific, targeted anti-neuroinflammatory strategies are required for effective treatment of HAND.

Chemical tools for the opioids

The opioids are potent and widely used pain management medicines despite also possessing severe liabilities that have fueled the opioid crisis. The pharmacological properties of the opioids primarily derive from agonism or antagonism of the opioid receptors, but additional effects may arise from specific compounds, opioid receptors, or independent targets. The study of the opioids, their receptors, and the development of remediation strategies has benefitted from derivatization of the opioids as chemical tools. While these studies have primarily focused on the opioids in the context of the opioid receptors, these chemical tools may also play a role in delineating mechanisms that are independent of the opioid receptors. In this review, we describe recent advances in the development and applications of opioid derivatives as chemical tools and highlight opportunities for the future.

The Synthetic Opioid Fentanyl Increases HIV Replication and Chemokine Co-Receptor Expression in Lymphocyte Cell Lines

BACKGROUND

In the United States, the illicit use of synthetic opioids such as fentanyl has led to a serious public health crisis. Synthetic opioids are known to enhance viral replication and to suppress immunologic responses, but their effects on HIV pathogenesis remain unclear. Thus, we examined the impact of fentanyl on HIV-susceptible and HIV-infected cell types.

METHODS

TZM-bl and HIV-infected lymphocyte cells were incubated with fentanyl at varying concentrations. Expression levels of the CXCR4 and CCR5 chemokine receptors and HIV p24 antigen were quantified with ELISA. HIV proviral DNA was quantified using SYBR RT-PCR. Cell viability was detected with the MTT assay. RNAseq was performed to characterize cellular gene regulation in the presence of fentanyl.

RESULTS

Fentanyl enhanced expression of both chemokine receptor levels in a dose-dependent manner in HIV-susceptible and infected cell lines. Similarly, fentanyl induced viral expression in HIV-exposed TZM-bl cells and in HIV-infected lymphocyte cell lines. Multiple genes associated with apoptosis, antiviral/interferon response, chemokine signaling, and NFκB signaling were differentially regulated.

CONCLUSIONS

Synthetic opioid fentanyl impacts HIV replication and chemokine co-receptor expression. Increased virus levels suggest that opioid use may increase the likelihood of transmission and accelerate disease progression.

ceAF Ameliorates Diabetic Wound Healing by Alleviating Inflammation and Oxidative Stress via TLR4/NF-κB and Nrf2 Pathways

Background. With the rise in diabetes incidence, diabetic foot ulcers have become the most common clinically chronic refractory wounds. Persistent chronic inflammation is a typical feature of diabetic cutaneous wounds, and diabetic wound healing can be improved by alleviating inflammation and oxidative stress. Chick early amniotic fluids (ceAF) consist of native conglutinant substances with balanced amounts of growth factors, cytokines, and chemokines. However, whether ceAF modulates inflammation and oxidative stress and thus promotes diabetic wound healing remains unknown. Materials and Methods. RAW264.7 cells were categorized into four groups: negative control, LPS, LPS + ceAF, and ceAF. 10% of ceAF was selected to treat different groups of mice with a full-thickness skin defect wound. Then, RT-qPCR, western blot, immunofluorescence, and other assays were carried out to explore the effect of ceAF on wound healing and its molecular mechanism. Results. Topical administration of ceAF improved M2 macrophage polarization and inflammatory response in the wound tissues, thereby ameliorating delayed wound healing. Histological improvement could be observed in the grade of inflammation, collagen deposition, and neovascularization in wound edge tissues. ceAF also increased M2 macrophage-specific markers expression and exogenous ceAF suppressed LPS-induced cellular inflammatory response in vitro high glucose environment. Additionally, ceAF could activate TLR4/NF-κB and Nrf2 signal transductions to promote M2 macrophage polarization in vitro. Conclusions. In summary, ceAF downregulates inflammatory response, regulates M2 macrophage transition via TLR4/NF-κB and Nrf2 signaling pathways, and thus improves diabetic wound healing.

Mu opioid receptor mRNA overexpression predicts poor prognosis among 18 common solid cancers: A pan-cancer analysis

Background

Opioids are widely used for patients with solid tumors during surgery and for cancer pain relief. We conducted a pan-cancer genomic analysis to investigate the prognostic features of Mu opioid receptor (MOR) mRNA expression across 18 primary solid cancers.

Methods

All the data of cancer with MOR mRNA were retrieved from cBioPortal for Cancer Genomics. Logistic regression was used to determine the associations between MOR mRNA expression and clinicopathological features. Log-rank test and Cox regression was used for survival analysis. Subgroup analysis and propensity score matching were also carried out.

Results

7,274 patients, including 1,112 patients with positive MOR mRNA expression, were included for data analyses. Positive MOR mRNA expression was associated with more advanced stage of T (adjusted Odds ratio [OR], 1.176; 95% confidence interval [CI], 1.022-1.354; P=0.024), M (adjusted OR, 1.548; 95% CI, 1.095-2.189; P=0.013) except N (adjusted OR, 1.145; 95% CI, 0.975-1.346; P=0.101), and worse prognosis for overall survival (Hazard ratio [HR] 1.347, 95% CI 1.200-1.512, P<0.001), progression-free survival (HR 1.359, 95% CI 1.220-1.513, P<0.001), disease-free survival (HR 1.269, 95% CI 1.016-1.585, P<0.001) and disease-specific survival (HR 1.474, 95% CI 1.284-1.693, P<0.001). Patients with positive MOR mRNA expression tended to be classified as tumor microenvironment immune types II, representing low PD-L1 and low CD8A expression.

Conclusion

MOR mRNA overexpression is associated with poor prognosis and poor response to PD-L1 therapy.

Single Nucleus Transcriptomics Reveals Pervasive Glial Activation in Opioid Overdose Cases

Dynamic interactions of neurons and glia in the ventral midbrain (VM) mediate reward and addiction behavior. We studied gene expression in 212,713 VM single nuclei from 95 human opioid overdose cases and drug-free controls. Chronic exposure to opioids left numerical proportions of VM glial and neuronal subtypes unaltered, while broadly affecting glial transcriptomes, involving 9.5 - 6.2% of expressed genes within microglia, oligodendrocytes, and astrocytes, with prominent activation of the immune response including interferon, NFkB signaling, and cell motility pathways, sharply contrasting with down-regulated expression of synaptic signaling and plasticity genes in VM non-dopaminergic neurons. VM transcriptomic reprogramming in the context of opioid exposure and overdose included 325 genes with genetic variation linked to substance use traits in the broader population, thereby pointing to heritable risk architectures in the genomic organization of the brain's reward circuitry.

Reductions in All-Cause Mortality Associated with the Use of Methylnaltrexone for Opioid-Induced Bowel Disorders: A Pooled Analysis

OBJECTIVE

Preclinical and clinical studies suggest that activation of the µ-opioid receptor may reduce overall survival and increase the risk for all-cause mortality in patients with cancer and noncancer pain. Methylnaltrexone, a selective, peripherally acting µ-opioid receptor antagonist, has demonstrated efficacy for the treatment of opioid-induced constipation. This retrospective analysis of 12 randomized, double-blind, placebo-controlled studies of methylnaltrexone evaluated the treatment of opioid-induced bowel disorders in patients with advanced illness or noncancer pain.

METHODS

The risk of all-cause mortality within 30 days after the last dose of study medication during the double-blind phase was compared between methylnaltrexone and placebo groups. The data were further stratified by cancer vs noncancer, age, gender, and acute vs chronic diagnoses.

RESULTS

Pooled data included 2,526 methylnaltrexone-treated patients of which 33 died, and 1,192 placebo-treated patients of which 35 died. The mortality rate was 17.8 deaths/100 person-years of exposure in the methylnaltrexone group and 49.5 deaths/100 person-years of exposure for the placebo group. The all-cause mortality risk was significantly lower among patients receiving methylnaltrexone compared with placebo (hazard ratio: 0.399, 95% confidence interval: 0.25, 0.64; P = .0002), corresponding to a 60% risk reduction. Significant risk reductions were observed for those receiving methylnaltrexone who had cancer or chronic diagnoses. Methylnaltrexone-treated patients had a significantly reduced mortality risk compared with placebo regardless of age or gender.

CONCLUSIONS

Methylnaltrexone reduced all-cause mortality vs placebo treatment across multiple trials, suggesting methylnaltrexone may confer survival benefits in patients with opioid-induced bowel disorders taking opioids for cancer-related or chronic noncancer pain.

N-type calcium channel blockers: a new approach towards the treatment of chronic neuropathic pain

Neuropathic pain (NP) remains maltreated for a wide number of patients by the currently available treatments and little research has been done in finding new drugs for treating NP. Ziconotide (PrialtTM) had been developed as the new drug, which belongs to the class of ω-conotoxin MVIIA. It inhibits N-type calcium channels. Ziconotide is under the last phase of the clinical trial, a new non-narcotic drug for the management of NP. Synthetically it has shown the similarities with ω-conotoxin MVIIA, a constituent of poison found in fish hunting snails (Conus magus). Ziconotide acts by selectively blocking neural N-type voltage-sensitized Ca2+ channels (NVSCCs). Certain herbal drugs also have been studied but no clinical result is there and the study is only limited to preclinical data. This review emphasizes the N-type calcium channel inhibitors, and their mechanisms for blocking calcium channels with their remedial prospects for treating chronic NP.

Depressive-like Behavior Is Accompanied by Prefrontal Cortical Innate Immune Fatigue and Dendritic Spine Losses after HIV-1 Tat and Morphine Exposure

Opioid use disorder (OUD) and HIV are comorbid epidemics that can increase depression. HIV and the viral protein Tat can directly induce neuronal injury within reward and emotionality brain circuitry, including the prefrontal cortex (PFC). Such damage involves both excitotoxic mechanisms and more indirect pathways through neuroinflammation, both of which can be worsened by opioid co-exposure. To assess whether excitotoxicity and/or neuroinflammation might drive depressive behaviors in persons infected with HIV (PWH) and those who use opioids, male mice were exposed to HIV-1 Tat for eight weeks, given escalating doses of morphine during the last two weeks, and assessed for depressive-like behavior. Tat expression decreased sucrose consumption and adaptability, whereas morphine administration increased chow consumption and exacerbated Tat-induced decreases in nesting and burrowing-activities associated with well-being. Across all treatment groups, depressive-like behavior correlated with increased proinflammatory cytokines in the PFC. Nevertheless, supporting the theory that innate immune responses adapt to chronic Tat exposure, most proinflammatory cytokines were unaffected by Tat or morphine. Further, Tat increased PFC levels of the anti-inflammatory cytokine IL-10, which were exacerbated by morphine administration. Tat, but not morphine, decreased dendritic spine density on layer V pyramidal neurons in the anterior cingulate. Together, our findings suggest that HIV-1 Tat and morphine differentially induce depressive-like behaviors associated with increased neuroinflammation, synaptic losses, and immune fatigue within the PFC.

EFFICACY AND SAFETY OF ORIGINAL DRUG BASED ON HEXAPEPTIDE SUCCINATE IN COMPLEX COVID-19 THERAPY IN ADULTS HOSPITALIZED PATIENTS

Currently, there are data that that make it possible to speak about a high clinical efficacy of the use of succinic salt of tyrosyl-D-alanyl-glycyl-phenylalanyl-leucyl-arginine (hexapeptide succinate) for the COVID-19 treatment. This article is devoted to the results of clinical trials of the original Russian drug based on it.

The aim of the study was to evaluate a clinical efficacy, safety and tolerability of intramuscular and inhalation use of hexapeptide succinate in complex therapy in comparison with standard therapy in patients with moderate COVID-19.

Materials and methods. The research was conducted from February 28, 2022 to November 22, 2022 based on 10 research centers in the Russian Federation. The study included hospitalized patients (n=312) over 18 years of age with moderate COVID-19 who had undergone a screening procedure and were randomized into 3 groups: group 1 received standard therapy in accordance with the Interim Guidelines in force at the time of the study, within 10 days; group 2 received hexapeptide succinate (Ambervin® Pulmo) intramuscularly at the dose of 1 mg once a day for 10 days; group 3 received hexapeptide succinate (Ambervin® Pulmo) 10 mg once a day by inhalation for 10 days.

Results. According to the results of the study, therapy with the drug hexapeptide succinate, both intramuscular and inhaled, provided an acceleration of recovery up to the complete absence of the disease signs in more than 80% of hospitalized COVID-19 patients. By the end of the therapy course with the drug, more than 60% of patients had met the criteria for discharge from hospital and could continue the treatment on an outpatient basis. About 70% of patients in the inhalation group and 80% in the intramuscular hexapeptide succinate injection group had concomitant diseases (hypertension – 28%, obesity – 14%), which indicates the effectiveness of this drug use in comorbid patients. The use of the drug contributed to the restoration of damaged lung tissues, normalization of oxygenation, the disappearance of shortness of breath and a decrease in the duration of the disease symptoms compared with standard therapy. As a result of a comparative analysis of adverse events in terms of their presence, severity, causal relationship with the therapy and outcome, there were no statistically significant differences between the treatment groups.

Conclusion. Thus, the results of the clinical study of the succinate hexapeptide efficacy and safety showed the feasibility of using the drug in pathogenetic therapy COVID-19 regimens.

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.

Crosstalk between Mu-Opioid receptors and neuroinflammation: Consequences for drug addiction and pain

Mu-Opioid Receptors (MORs) are well-known for participating in analgesia, sedation, drug addiction, and other physiological functions. Although MORs have been related to neuroinflammation their biological mechanism remains unclear. It is suggested that MORs work alongside Toll-Like Receptors to enhance the release of pro-inflammatory mediators and cytokines during pathological conditions. Some cytokines, including TNF-α, IL-1β and IL-6, have been postulated to regulate MORs levels by both avoiding MOR recycling and enhancing its production. In addition, Neurokinin-1 Receptor, also affected during neuroinflammation, could be regulating MOR trafficking. Therefore, inflammation in the central nervous system seems to be associated with altered/increased MORs expression, which might regulate harmful processes, such as drug addiction and pain. Here, we provide a critical evaluation on MORs' role during neuroinflammation and its implication for these conditions. Understanding MORs' functioning, their regulation and implications on drug addiction and pain may help elucidate their potential therapeutic use against these pathological conditions and associated disorders.

Accelerated brain aging with opioid misuse and HIV: New insights on the role of glially derived pro-inflammation mediators and neuronal chloride homeostasis

Opioid use disorder (OUD) has become a national crisis and contributes to the spread of human immunodeficiency virus (HIV) infection. Emerging evidence and advances in experimental models, methodology, and our understanding of disease processes at the molecular and cellular levels reveal that opioids per se can directly exacerbate the pathophysiology of neuroHIV. Despite substantial inroads, the impact of OUD on the severity, development, and prognosis of neuroHIV and HIV-associated neurocognitive disorders is not fully understood. In this review, we explore current evidence that OUD and neuroHIV interact to accelerate cognitive deficits and enhance the neurodegenerative changes typically seen with aging, through their effects on neuroinflammation. We suggest new thoughts on the processes that may underlie accelerated brain aging, including dysregulation of neuronal inhibition, and highlight findings suggesting that opioids, through actions at the μ-opioid receptor, interact with HIV in the central nervous system to promote unique structural and functional comorbid deficits not seen in either OUD or neuroHIV alone.

Structures of the entire human opioid receptor family

Opioids are effective analgesics, but their use is beset by serious side effects, including addiction and respiratory depression, which contribute to the ongoing opioid crisis. The human opioid system contains four opioid receptors (μOR, δOR, κOR, and NOPR) and a set of related endogenous opioid peptides (EOPs), which show distinct selectivity toward their respective opioid receptors (ORs). Despite being key to the development of safer analgesics, the mechanisms of molecular recognition and selectivity of EOPs to ORs remain unclear. Here, we systematically characterize the binding of EOPs to ORs and present five structures of EOP-OR-Gi complexes, including β-endorphin- and endomorphin-bound μOR, deltorphin-bound δOR, dynorphin-bound κOR, and nociceptin-bound NOPR. These structures, supported by biochemical results, uncover the specific recognition and selectivity of opioid peptides and the conserved mechanism of opioid receptor activation. These results provide a structural framework to facilitate rational design of safer opioid drugs for pain relief.

Long-term effect of anesthesia choice on patients with hepatocellular carcinoma undergoing open liver resection

Clinical and experimental evidence suggested that anesthesia choice can influence cancer progression and patients' outcomes by modulating tumor microenvironment and tumorigenic pathways. Curative resection is the mainstay of therapy for hepatocellular carcinoma (HCC), which is an intractable disease due to high recurrence and poor prognosis. However, different anesthetics may play different roles in alleviating surgery-induced stress response and inflammatory cytokines release that are considered to be closely associated with proliferation, invasion and metastasis of tumor cells. Propofol, sevoflurane, non-steroidal anti-inflammatory drugs and local anesthetics have shown to exert anti-tumor effect on HCC mainly through regulating microRNAs or signaling pathways, while other inhalational agents, dexmedetomidine and opioids have the potential to promote tumor growth. In terms of anesthetic methods and analgesia strategies, propofol based total intravenous anesthesia and thoracic epidural analgesia could be preferred for HCC patients undergoing open liver resection rather than inhalational anesthesia. Local anesthesia techniques have great potential to attenuate perioperative stress response, hence they may contribute to more favorable outcomes. This review summarized the relations between different anesthesia choices and HCC patients' long-term outcomes as well as their underlying mechanisms. Due to the complexity of molecules interactions and signaling pathways, further studies are warranted to confirm these results so as to optimize anesthesia strategy for HCC patients.

Prevalence of COVID-19 outcomes in patients referred to opioid agonist treatment centers

Background: Coronavirus disease (COVID-19) is a mild to severe infectious respiratory illness caused by the SARS-CoV-2 virus. Based on the numerous pieces of evidence regarding the role of opioids in immune function, viral replication, and virus-mediated pathology, we decided to assess the incidence and severity of COVID-19 outcomes in people undergoing opioid maintenance treatment. Methods: This is a prospective, descriptive, multi-center study that included 452 patients undergoing maintenance treatment in opioid agonist treatment (OAT) clinics in different cities of Iran. Demographic information, underlying disease, history of maintenance treatment, type of drug used, history of addiction, smoking, and the kind of substance abused, were recorded. A physician evaluated the COVID-19 symptoms, and the severity of the disease was defined based on the number of observed symptoms. Results: The results have not shown any significant difference in the severity of COVID-19 symptoms in different nationalities, gender, and treatment groups. Furthermore, the history of drug abuse, including time and type of abuse and smoking, has not indicated any significant association with the occurrence of symptoms. Only the severity of COVID-19 in the mentioned cities (first and second follow-up: p < 0.001) and individuals with a history of underlying disease (first follow-up: p = 0.020; second follow-up: p = 0.043) were significantly different. Conclusion: Our results have demonstrated that the severity of symptoms in people with the underlying disease was significantly higher than in others. But there is no association between sex, race, treatment groups, and abuse history with the severity of COVID-19 symptoms in methadone maintenance treatment (MMT) patients.

Transcriptomics and metabolomics together reveal the underlying mechanism of heroin hepatotoxicity

Researches on heroin are more about addiction and some infectious diseases it causes, but liver fibrosis caused by heroin abuse and the mechanism of heroin hepatotoxicity in addicts are ignored. To explore the mechanism of heroin hepatotoxicity, mice in heroin group were intraperitoneally injected by heroin (10 mg/kg) once a day for 14 consecutive days, while mice in heroin withdraw group underwent another 7 days without heroin administration after the same treatment as heroin group. The levels of alanine aminotransferase （ALT）and aspartate aminotransferase （AST） in serum, as biochemical indexes, were applied to evaluate liver damage. H & E staining and oil red O staining were used to observe the pathological changes of liver. Transcriptomics and metabolomics were applied to detect genes and metabolites in livers. The results of biochemical analysis and pathological examination showed that heroin induced liver damage and lipid loss in mice, and these mice did not return to normal completely after a short-term withdrawal. A total of 511 differential genes and 78 differential metabolites were identified by transcriptomics and metabolomics. These differential genes and metabolites were significantly enriched in pathways like lipid metabolism, arachidonic acid metabolism, glutathione metabolism, TCA cycle. And after undergoing 7-day withdrawal of heroin, most of the above differential genes and metabolites did not return to normal. Our study revealed the hepatotoxicity of heroin and that short-term withdrawal of heroin did not fully restore liver function. In addition, transcriptomics and metabolomics revealed that lipid metabolism and arachidonic acid metabolism may be potential therapeutic targets of heroin hepatotoxicity, providing a basis for the treatment of heroin addiction patients in the future.

Microglial knockdown does not affect acute withdrawal but delays analgesic tolerance from oxycodone in male and female C57BL/6J mice

Opioid Use Disorder (OUD) affects approximately 8%-12% of the population. In dependent individuals, abrupt cessation of opioid taking results in adverse withdrawal symptoms that reinforce drug taking behavior. Considerable unmet clinical need exists for new pharmacotherapies to treat opioid withdrawal as well as improve long-term abstinence. The neuroimmune system has received much scientific attention in recent years as a potential therapeutic target to combat various neurodegenerative and psychiatric disorders including addiction. However, the specific contribution of microglia has not been investigated in oxycodone dependence. Chronic daily treatment with the CSF1R inhibitor Pexidartinib (PLX3397) was administered to knockdown microglia expression and evaluate consequences on analgesia and on naloxone induced withdrawal from oxycodone. In vivo results indicated that an approximately 40% reduction in brain IBA1 staining was achieved in the PLX treatment group, which was associated with a delay in the development of analgesic tolerance to oxycodone and maintained antinociceptive efficacy. Acute withdrawal behavioral symptoms, brain astrocyte expression, and levels of many neuroinflammatory markers were not affected by PLX treatment. KC/GRO (also known as CXCL1) was significantly enhanced in the somatosensory cortex in oxycodone-treated mice receiving PLX. Microglial knock-down did not affect the expression of naloxoneinduced opioid withdrawal but affected antinociceptive responsivity. The consequences of increased KC/GRO expression within the somatosensory cortex due to microglial reduction during opioid dependence are unclear but may be important for neural pathways mediating opioid-induced analgesia.

Morphine suppresses the immune function of lung cancer by up-regulating MAEL expression

BACKGROUND

Patients with cancer rely on morphine for analgesia, while studies have indicated morphine can induce immunosuppression in cancer. Therefore, investigating the immunosuppressive roles and molecular mechanism of morphine on lung cancer progression is imperative.

METHODS

Lactate dehydrogenase (LDH) release assay was used to determine the cytotoxicity of morphine to lung cancer cells. The percentage of CD4⁺ and CD8⁺ T cells was detected by flow cytometry. In addition, Maelstrom (MAEL), Nrf2, and PTEN were determined by western blot and RT-qPCR. Immune factors programmed death-ligand 1 (PD-L1), transforming growth factor (TGF-β), interleukin (IL)-10, and IL-2 were determined by western blot and ELISA assay.

RESULTS

Morphine increased the levels of PD-L1, TGF-β, and IL-10, while decreased IL-2 level. Morphine enhanced MAEL expression in A549 cells and H460 cells. Morphine up-regulated Nrf2 and down-regulated PTEN, and morphine-induced MAEL up-regulation was reversed by PTEN. However, MAEL silencing inhibited the enhanced effects of morphine on cell viability and proliferation of A549 cells. Furthermore, morphine treatment reduced the LDH release and the percentage of CD8⁺ T cells, and increased the ratio of CD4⁺/CD8⁺ T cells and tumor weight. Meanwhile, MAEL silencing reversed the effects of morphine on immune factors (PD-L1, TGF-β, IL-10, and IL-2), the percentage of CD8⁺ T cells, and the ratio of CD4⁺/CD8⁺ T cells.

CONCLUSION

Morphine activated MAEL in lung cancer cells by Nrf2/PTEN pathway and regulated the immune factors, thereby promoting tumor immune escape.

[The challenges of managing thoracic pain in cystic fibrosis (CF)]

BACKGROUND

Cystic fibrosis (CF) is a rare genetic multisystemic disorder with progressive abdominal and pulmonary involvement. Pain is still an underestimated symptom in CF patients.

METHODS

A comprehensive review of guidelines and scientific literature on the topic was performed and combined with findings from pain management in a young CF patient with progressive thoracic pain.

RESULTS

German CF guidelines do not cover diagnosis and management of pain in these patients. Studies from Europe and the United States report interactions between intensity of pain and mortality in CF, but do not include data on the efficacy of pain management. These data and clinical observations of a CF patient with episodes of intense thoracic pain are used to illustrate the specific challenges in pain relief.

CONCLUSION

Pain management in CF requires meticulous monitoring as well as an interdisciplinary approach and should be implemented in the German CF guidelines. The authors also want to suggest recommendations for the treatment of thoracic pain in CF. The range and severity of organ involvement complicates the use both of opioids and non-opioids. Especially opioid treatment carries the risk of hypoxia and opioid-induced constipation (OIC) and needs close medical supervision.

Bench to Bedside: Modelling Inflammatory Arthritis

Inflammatory arthritides such as rheumatoid arthritis are a major cause of disability. Pre-clinical murine models of inflammatory arthritis continue to be invaluable tools with which to identify and validate therapeutic targets and compounds. The models used are well-characterised and, whilst none truly recapitulates the human disease, they are crucial to researchers seeking to identify novel therapeutic targets and to test efficacy during preclinical trials of novel drug candidates. The arthritis parameters recorded during clinical trials and routine clinical patient care have been carefully standardised, allowing comparison between centres, trials, and treatments. Similar standardisation of scoring across in vivo models has not occurred, which makes interpretation of published results, and comparison between arthritis models, challenging. Here, we include a detailed and readily implementable arthritis scoring system, that increases the breadth of arthritis characteristics captured during experimental arthritis and supports responsive and adaptive monitoring of disease progression in murine models of inflammatory arthritis. In addition, we reference the wider ethical and experimental factors researchers should consider during the experimental design phase, with emphasis on the continued importance of replacement, reduction, and refinement of animal usage in arthritis research.

Effect of Opioids on Survival in Patients with Cancer

Opioids are commonly used for pain management in patients with cancer. They have a range of unwanted effects, including some that potentially influence cancer growth. This article reviews the data assessing the effects of opioids on survival in patients with cancer. Many studies assessing this show an association between opioids and decreased survival. This effect is present even at very low doses of opioids. These studies do not assess causality, so it is not known if it is a direct effect of opioids on survival. As the control groups are not matched to the opioid group it might be that opioids are being used to control pain and patients receiving opioids have more aggressive cancers and it is the underlying cancer which is causing the decreased survival. Furthermore, although some studies allude to different opioids having different effects on survival, often all opioids are pooled in analysis. Future work needs to try to ascertain causality and differentiate between different opioids, pain, and cancer-mediated effects on survival in specific cancer types. Until then, opioids should continue to be used in patients with cancer as part of measures to optimise comfort and quality of life.

Morphine suppresses peripheral responses and transforms brain myeloid gene expression to favor neuropathogenesis in SIV infection

The twin pandemics of opioid abuse and HIV infection can have devastating effects on physiological systems, including on the brain. Our previous work found that morphine increased the viral reservoir in the brains of treated SIV-infected macaques. In this study, we investigated the interaction of morphine and SIV to identify novel host-specific targets using a multimodal approach. We probed systemic parameters and performed single-cell examination of the targets for infection in the brain, microglia and macrophages. Morphine treatment created an immunosuppressive environment, blunting initial responses to infection, which persisted during antiretroviral treatment. Antiretroviral drug concentrations and penetration into the cerebrospinal fluid and brain were unchanged by morphine treatment. Interestingly, the transcriptional signature of both microglia and brain macrophages was transformed to one of a neurodegenerative phenotype. Notably, the expression of osteopontin, a pleiotropic cytokine, was significantly elevated in microglia. This was especially notable in the white matter, which is also dually affected by HIV and opioids. Increased osteopontin expression was linked to numerous HIV neuropathogenic mechanisms, including those that can maintain a viral reservoir. The opioid morphine is detrimental to SIV/HIV infection, especially in the brain.

Personalized Medicine for Classical Anesthesia Drugs and Cancer Progression

In this review, we aim to discuss the use and effect of five different drugs used in the induction of anesthesia in cancer patients. Propofol, fentanyl, rocuronium, sugammadex, and dexamethasone are commonly used to induce anesthesia and prevent pain during surgery. Currently, the mechanisms of these drugs to induce the state of anesthesia are not yet fully understood, despite their use being considered safe. An association between anesthetic agents and cancer progression has been determined; therefore, it is essential to recognize the effects of all agents during cancer treatment and to evaluate whether the treatment provided to the patients could be more precise. We also highlight the use of in silico tools to review drug interaction effects and safety, as well as the efficacy of the treatment used according to different subgroups of patients.

Exploring the role of the endogenous opiate system in the pathogenesis of anemia in an opiate receptor knock-out model of Restless Legs Syndrome

Restless Legs Syndrome (RLS) is characterized by bothersome leg discomfort accompanied by an urge to move to obtain relief and symptoms are worse at night and on lying down. There is at least partial and temporary relief with activity. It is also an opioid responsive disorder, often accompanied by iron deficiency with or without anemia, and inflammation may be a precipitating factor in some cases. We created two in-vivo opiate receptor knock out mouse models of RLS - a triple opiate receptor knock-out mouse and a mu opiate receptor knock-out mouse. Both sets of animals were restless during the sleep period as is also true of RLS. Both of our knockout models showed statistically significantly decreased Hemoglobin and Hematocrit indicating anemia and both models showed statistically significant decreases in serum iron suggestive of either iron deficiency anemia or inflammatory anemia. The rest of the hematologic studies were not consistent enough to determine which of these two types of anemia was present in either model. An additional experiment in normal wild type mice showed a statistically significant decrease in serum iron when an opiate receptor blocker was used. To our knowledge this is the first demonstration that deficiency of endogenous opioids might play a role in the production of anemia. Our hypothesis is that an intact endogenous opiate system is necessary for red cell homeostasis. The presence of opioid receptors both on red blood cells and on various immunologically based white blood cells suggest mechanisms by which deficiency in the endogenous opiate system could cause anemia of either the iron deficiency or inflammatory types. The administration of opioid agonists or antagonists to iron deficient cultures of red blood cell precursors is a next step in determining the role of the endogenous opiate system in the maintenance of red cell homeostasis and in the possible prevention of iron deficiency or inflammatory anemia where iron dysregulation is key.

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.

Association Between Inflammatory Cytokines, Executive Function, and Substance Use in Patients With Opioid Use Disorder and Amphetamine-Type Stimulants Use Disorder

BACKGROUND

Long-term opioid and amphetamine-type stimulants (ATS) abuse may affect immunological function and impair executive function. We aimed to determine whether biomarkers of inflammation and executive function were associated with substance use in individuals with opioid use disorder (OUD) and ATS use disorder (ATSUD). The interactions between these biomarkers were also explored.

METHODS

We assessed plasma cytokines [tumor necrosis factor (TNF)-α, C-reactive protein (CRP), interleukin (IL)-8, IL-6, transforming growth factor (TGF)-β1, brain-derived neurotrophic factor (BDNF), and executive function in terms of the Wisconsin Card Sorting Test (WCST) and Continuous Performance Test (CPT) in OUD and ATSUD patients and healthy controls (HC). OUD and ATSUD patients were followed for 12 weeks, and their urine morphine and amphetamine tests, cytokine levels, and executive function were repeatedly measured.

RESULTS

We enrolled 483 patients and 145 HC. Plasma TNF-α, CRP, IL-8, IL-6, and BDNF levels and most subscale scores on the WCST and CPT significantly differed between OUD and ATSUD patients and HC. Increased TNF-α levels and more perseveration error on the WCST were significantly associated with more urine drug-positive results and less abstinence. Plasma IL-6 and CRP levels were significantly negatively correlated with WCST and CPT performance.

CONCLUSION

OUD and ATSUD patients had more inflammation and worse executive function than HC. Inflammatory markers and WCST performance were associated with their urinary drug results, and higher inflammation was associated with poor executive function. Studies on regulating the inflammatory process and enhancing executive function in OUD and ATSUD are warranted.

Multi-chemokine receptor antagonist RAP-103 inhibits opioid-derived respiratory depression, reduces opioid reinforcement and physical dependence, and normalizes opioid-induced dysregulation of mesolimbic chemokine receptors in rats

Chemokine-opioid crosstalk is a physiological crossroads for influencing therapeutic and adverse effects of opioids. Activation of chemokine receptors, especially CCR2, CCR5 and CXCR4, reduces opioid-induced analgesia by desensitizing OPRM1 receptors. Chemokine receptor antagonists (CRAs) enhance opioid analgesia, but knowledge about how CRAs impact adverse opioid effects remains limited. We examined effects of RAP-103, a multi-CRA orally active peptide analog of "DAPTA", on opioid-derived dependence, reinforcement, and respiratory depression in male rats and on changes in chemokine and OPRM1 (µ opioid) receptor levels in mesolimbic substrates during opioid abstinence. In rats exposed to chronic morphine (75 mg pellet x 7 d), daily RAP-103 (1 mg/kg, IP) treatment reduced the severity of naloxone-precipitated withdrawal responses. For self-administration (SA) studies, RAP-103 (1 mg/kg, IP) reduced heroin acquisition (0.1 mg/kg/inf) and reinforcing efficacy (assessed by motivation on a progressive-ratio reinforcement schedule) but did not impact sucrose intake. RAP-103 (1-3 mg/kg, IP) also normalized the deficits in oxygen saturation and enhancement of respiratory rate caused by morphine (5 mg/kg, SC) exposure. Abstinence from chronic morphine elicited brain-region specific changes in chemokine receptor protein levels. CCR2 and CXCR4 were increased in the ventral tegmental area (VTA), whereas CCR2 and CCR5 were reduced in the nucleus accumbens (NAC). Effects of RAP-103 (1 mg/kg, IP) were focused in the NAC, where it normalized morphine-induced deficits in CCR2 and CCR5. These results identify CRAs as potential biphasic function opioid signaling modulators to enhance opioid analgesia and inhibit opioid-derived dependence and respiratory depression.

The Dose-Dependent Effects of Multifunctional Enkephalin Analogs on the Protein Composition of Rat Spleen Lymphocytes, Cortex, and Hippocampus; Comparison with Changes Induced by Morphine

This work aimed to test the effect of 7-day exposure of rats to multifunctional enkephalin analogs LYS739 and LYS744 at doses of 3 mg/kg and 10 mg/kg on the protein composition of rat spleen lymphocytes, brain cortex, and hippocampus. Alterations of proteome induced by LYS739 and LYS744 were compared with those elicited by morphine. The changes in rat proteome profiles were analyzed by label-free quantification (MaxLFQ). Proteomic analysis indicated that the treatment with 3 mg/kg of LYS744 caused significant alterations in protein expression levels in spleen lymphocytes (45), rat brain cortex (31), and hippocampus (42). The identified proteins were primarily involved in RNA processing and the regulation of cytoskeletal dynamics. In spleen lymphocytes, the administration of the higher 10 mg/kg dose of both enkephalin analogs caused major, extensive modifications in protein expression levels: LYS739 (119) and LYS744 (182). Among these changes, the number of proteins associated with immune responses and apoptotic processes was increased. LYS739 treatment resulted in the highest number of alterations in the rat brain cortex (152) and hippocampus (45). The altered proteins were functionally related to the regulation of transcription and cytoskeletal reorganization, which plays an essential role in neuronal plasticity. Administration with LYS744 did not increase the number of altered proteins in the brain cortex (26) and hippocampus (26). Our findings demonstrate that the effect of κ-OR full antagonism of LYS744 is opposite in the central nervous system and the peripheral region (spleen lymphocytes).

Is the Neuroimmune System a Therapeutic Target for Opioid Use Disorder? A Systematic Review

Opioid use disorder (OUD) is an epidemic in the United States. In the past 12 months alone, there have been 75,000+ deaths attributed to opioid overdose: more than any other year in American history. Current pharmacotherapies for the treatment of OUD effectively suppress opioid withdrawal symptoms, but long-term relapse rates remain unacceptably high. Novel treatments for OUD are desperately needed to curb this epidemic. One target that has received considerable recent interest is the neuroimmune system. The neuroimmune system is anchored by glial cells, i.e., microglia and astrocytes, but neuroimmune signaling is known to influence neurons, including altering neurotransmission, synapse formation, and ultimately, brain function. Preclinical studies have shown that experimental attenuation of pro-inflammatory neuroimmune signaling modulates opioid addiction processes, including opioid reward, tolerance, and withdrawal symptoms, which suggests potential therapeutic benefit in patients. Whereas the peripheral immune system in OUD patients has been studied for decades and is well-understood, little is known about the neuroimmune system in OUD patients or its viability as a treatment target. Herein, we review the literature describing relationships between opioid administration and the neuroimmune system, the influence of neuroimmune signaling on opioid addiction processes, and the therapeutic potential for targeting the neuroimmune system in OUD subjects using glial modulator medications.

Anesthesia and cancer recurrence: an overview

Several perioperative factors are responsible for the dysregulation or suppression of the immune system with a possible impact on cancer cell growth and the development of new metastasis. These factors have the potential to directly suppress the immune system and activate hypothalamic-pituitary-adrenal axis and the sympathetic nervous system with a consequent further immunosuppressive effect.Anesthetics and analgesics used during the perioperative period may modulate the innate and adaptive immune system, inflammatory system, and angiogenesis, with a possible impact on cancer recurrence and long-term outcome. Even if the current data are controversial and contrasting, it is crucial to increase awareness about this topic among healthcare professionals for a future better and conscious choice of anesthetic techniques.In this article, we aimed to provide an overview regarding the relationship between anesthesia and cancer recurrence. We reviewed the effects of surgery, perioperative factors, and anesthetic agents on tumor cell survival and tumor recurrence.

Perioperative Inflammatory Response and Cancer Recurrence in Lung Cancer Surgery: A Narrative Review

While surgical resection is the gold standard treatment for solid tumors, cancer recurrence after surgery is common. Immunosurveillance of remnant tumor cells is an important protective mechanism. Therefore, maintenance of anti-tumor cell activity and proper levels of inflammatory mediators is crucial. An increasing body of evidence suggests that surgery itself and perioperative interventions could affect these pathophysiological responses. Various factors, such as the extent of tissue injury, perioperative medications such as anesthetics and analgesics, and perioperative management including transfusions and methods of mechanical ventilation, modulate the inflammatory response in lung cancer surgery. This narrative review summarizes the pathophysiological mechanisms involved in cancer recurrence after surgery and perioperative management related to cancer recurrence after lung cancer surgery.

Neutrophil-to-Lymphocyte Ratio as an Indicator of Opioid-Induced Immunosuppression After Thoracoscopic Surgery: A Randomized Controlled Trial

Purpose

The neutrophil-to-lymphocyte ratio (NLR) is a useful prognostic marker for various diseases and surgery-induced immunosuppression. While opioids are important in general anesthesia, the association between immediate perioperative immune monitoring and opioid consumption for postoperative analgesia after video-assisted thoracoscopic surgery (VATS) is unknown. We aimed to investigate the effect of analgesic techniques on opioid-induced immune perturbation, and the feasibility of NLR as an indicator of opioid-induced immune changes.

Patients and Methods

Patients were randomly assigned to two groups: Group P (n=40) or Group C (n=40). Patients in group P received ultrasound-guided paravertebral block (PVB) before surgery, and followed by sufentanil patient-controlled intravenous analgesia (PCIA) after surgery, and group C received sufentanil PCIA only. The total and differential white blood cell counts, including CD4+ T lymphocyte counts, CD8+ T lymphocyte were recorded before surgery and at 24 and 72 hours after surgery. NLR was determined using the frequencies of lymphocyte subpopulations. The cumulative dose of sufentanil were recorded at 24 and 24h after surgery while the 40-item quality of recovery questionnaire (QoR-40) score were assessed at 48h after the surgery.

Results

At 24 and 48 hours after surgery, a lower sufentanil consumption, and higher QoR-40 recovery scores were found in group P than in group C (P<0.05). In biochemical analyses, the values of NLR were lower in group P compared to group C (p<0.0001) and ratio of CD4/CD8 were higher in group P compared to group C (p<0.05) on day three after surgery. NLR showed excellent predictive capability for immunosuppression, with an area under the curve (AUC) of 0.92 [95% confidence interval (CI), 0.86-0.98, P < 0.0001].

Conclusion

Opioid-sparing pain management strategies may affect postoperative immunosuppression and NLR could be a reliable indicator of opioid-related immunosuppression. Moreover, opioid-sparing pain management strategies could improve patient's satisfaction in VATS.

The Kappa Opioid Receptor: A Promising Therapeutic Target for Multiple Pathologies

Kappa-opioid receptors (KOR) are widely expressed throughout the central nervous system, where they modulate a range of physiological processes depending on their location, including stress, mood, reward, pain, inflammation, and remyelination. However, clinical use of KOR agonists is limited by adverse effects such as dysphoria, aversion, and sedation. Within the drug-development field KOR agonists have been extensively investigated for the treatment of many centrally mediated nociceptive disorders including pruritis and pain. KOR agonists are potential alternatives to mu-opioid receptor (MOR) agonists for the treatment of pain due to their anti-nociceptive effects, lack of abuse potential, and reduced respiratory depressive effects, however, dysphoric side-effects have limited their widespread clinical use. Other diseases for which KOR agonists hold promising therapeutic potential include pruritis, multiple sclerosis, Alzheimer's disease, inflammatory diseases, gastrointestinal diseases, cancer, and ischemia. This review highlights recent drug-development efforts targeting KOR, including the development of G-protein-biased ligands, mixed opioid agonists, and peripherally restricted ligands to reduce side-effects. We also highlight the current KOR agonists that are in preclinical development or undergoing clinical trials.

Opioid Receptor-Mediated Regulation of Neurotransmission in the Brain

Opioids mediate their effects via opioid receptors: mu, delta, and kappa. At the neuronal level, opioid receptors are generally inhibitory, presynaptically reducing neurotransmitter release and postsynaptically hyperpolarizing neurons. However, opioid receptor-mediated regulation of neuronal function and synaptic transmission is not uniform in expression pattern and mechanism across the brain. The localization of receptors within specific cell types and neurocircuits determine the effects that endogenous and exogenous opioids have on brain function. In this review we will explore the similarities and differences in opioid receptor-mediated regulation of neurotransmission across different brain regions. We discuss how future studies can consider potential cell-type, regional, and neural pathway-specific effects of opioid receptors in order to better understand how opioid receptors modulate brain function.

Z-Guggulsterone attenuates cognitive defects and decreases neuroinflammation in APPswe/PS1dE9 mice through inhibiting the TLR4 signaling pathway

Growing evidence indicates that inflammatory damage is implicated in the pathogenesis of Alzheimer's disease (AD). Z-Guggulsterone (Z-GS) is a natural steroid, which is extracted from Commiphora mukul and has anti-inflammatory effects in vivo and in vitro. In the present study, we investigated the disease-modifying effects of chronic Z-GS administration on the cognitive and neuropathological impairments in the transgenic mouse models of AD. We found that chronic Z-GS administration prevented learning and memory deficits in the APPswe/PS1dE9 mice. In addition, Z-GS treatment significantly decreased cerebral amyloid-β (Aβ) levels and plaque burden via inhibiting amyloid precursor protein (APP) processing by reducing beta-site APP cleaving enzyme 1 (BACE1) expression in the APPswe/PS1dE9 mice. We also found that Z-GS treatment markedly alleviated neuroinflammation and reduced synaptic defects in the APPswe/PS1dE9 mice. Furthermore, the activated TLR4/NF-κB signaling pathways in APPswe/PS1dE9 mice were remarkably inhibited by Z-GS treatment, which was achieved via suppressing the phosphorylation of JNK. Collectively, our data demonstrate that chronic Z-GS treatment restores cognitive defects and reverses multiple neuropathological impairments in the APPswe/PS1dE9 mice. This study provides novel insights into the neuroprotective effects and neurobiological mechanisms of Z-GS on AD, indicating that Z-GS is a promising disease-modifying agent for the treatment of AD.

Opioid-Use, COVID-19 Infection, and Their Neurological Implications

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an imminent threat to human health and public safety. ACE2 and transmembrane serine protease 2 proteins on host cells provide the viral entry point to SARS-CoV-2. Although SARS-CoV-2 mainly infects the respiratory system, there have been reports of viral neurotropism and central nervous system injury as indicated by plasma biomarkers, including neurofilament light chain protein and glial fibrillary acidic protein. Even with a small proportion of infections leading to neurological manifestation, the overall number remains high. Common neurological manifestations of SARS-CoV-2 infection include anosmia, ageusia, encephalopathy, and stroke, which are not restricted to only the most severe infection cases. Opioids and opioid antagonists bind to the ACE2 receptor and thereby have been hypothesized to have therapeutic potential in treating COVID-19. However, in the case of other neurotropic viral infections such as human immunodeficiency virus (HIV), opioid use has been established to exacerbate HIV-mediated central nervous system pathogenesis. An analysis of electronic health record data from more than 73 million patients shows that people with Substance Use Disorders are at higher risk of contracting COVID-19 and suffer worse consequences then non-users. Our in-vivo and in-vitro unpublished studies show that morphine treatment causes increased expression of ACE2 in murine lung and brain tissue as early as 24 h post treatment. At the same time, we also observed morphine and lipopolysaccharides treatment lead to a synergistic increase in ACE2 expression in the microglial cell line, SIM-A9. This data suggests that opioid treatment may potentially increase neurotropism of SARS-CoV-2 infection. We have previously shown that opioids induce gut microbial dysbiosis. Similarly, gut microbiome alterations have been reported with SARS-CoV-2 infection and may play a role in predicting COVID-19 disease severity. However, there are no studies thus far linking opioid-mediated dysbiosis with the severity of neuron-specific COVID-19 infection.