Opioid-induced immunosuppression and carcinogenesis promotion theories create the newest trend in acute and chronic pain pharmacotherapy

Prevalence and predictors of multidrug resistant organism infections in critically ill patients with opioid use disorder: a multicenter retrospective cohort study

OBJECTIVE

Patients with Opioid Use Disorder (OUD) are prone to Multidrug-Resistant Organism (MDRO) colonization and infections, thus at risk for worse outcomes during critical illness. Understanding the prevalence and predictors of MDRO infections is essential to optimize interventions and treatments.

DESIGN

Retrospective cohort study.

METHODS

The study evaluated the prevalence of MDRO isolation among adults with OUD admitted to an intensive care unit (ICU) between January 1, 2018, and July 31, 2023. It included adults admitted to an ICU with bacterial infections and positive cultures obtained within 48 hours of admission. Demographics, clinical traits, and MDRO isolation rates were analyzed using descriptive statistics, univariate methods, and Least Absolute Shrinkage and Selection Operator (LASSO) regression.

RESULTS

MDRO isolation occurred in 178 of 790 patients (22.5%), with methicillin-resistant Staphylococcus aureus as the most frequently isolated organism. LASSO regression identified housing insecurity (OR: 1.79, 95% CI 1.09-2.93, P = .022), no receipt of medications for OUD treatment (OR: 1.56, 95% CI 1.06-2.29, P = .023), positive hepatitis C virus (HCV) status (OR: 2.19, 95% CI 1.19-4.03, P = .012), and intravenous antibiotic use in the prior 90 days (OR: 1.04 per 24 h, 95% CI 1.01-1.07, P = .007) as significant predictors of MDRO isolation.

CONCLUSIONS

The study highlights a high prevalence of MDRO isolation in critically ill OUD patients admitted for infection-related issues with positive cultures obtained within 48 hours of admission, influenced by factors like housing insecurity, no receipt of medications for OUD treatment, HCV status, and prior antibiotic use.

Sex-Related Analgesic Effects of Opioid-Based Anesthesia and Low-Opioid Anesthesia with Non-Opioid Postoperative Analgesia-A Clinical Observational Study

Background/Objectives: Sex is a crucial factor in modulating the perioperative aspects of anesthesia. A growing number of studies demonstrate that women and men experience pain differently and respond differentially to analgesics. Methods: This study evaluated the analgesic trajectory of low-opioid anesthesia (LOA) and opioid-based anesthesia (OBA) in women and men after laparoscopic cholecystectomy. The primary objective was to assess pain intensity at various time intervals after surgery (0-2, 2-6, 6-12, and 12-24 h) using the Numerical Rating Scale (NRS). The secondary objective was to assess the difference in mean pain intensity on the first postoperative day between the women and men. Results: The mean pain intensity did not differ significantly for men using LOA and OBA, but the value was significantly lower in the LOA group for women (p = 0.0002). The analgesic trajectory in women and men undergoing LOA presented a negative trend, but the pain intensity at 0-2, 2-6, 6-12, and 12-24 h in women was statistically lower than that of the OBA group (p = 0.01, p = 0.008, p = 0.002, and p = 0.001). Total fentanyl doses of 0.3 mg (sensitivity 44%, specificity 76%, AUC 0.55) and 0.35 mg achieved a mean NRS of <2 for pain intensity in the female and male OBA groups (sensitivity 33%, specificity 100%, AUC 0.53). Conclusions: A model combining low-opioid anesthesia and non-opioid postoperative analgesia presents a favorable therapeutic effect for women. OBA does not provide proper analgesic effects after laparoscopic cholecystectomy.

Transdermal Fentanyl Patch Effectiveness in Postoperative PainManagement in Orthopedic Patients: Literature Review

Controlling pain after major orthopedic surgery may be challenging, and it is related to delayed recovery, the development of chronic pain, and analgesic dependence. It is well known that effective postoperative pain control can reduce hospital stays by ensuring a more rapid rehabilitation,thereby decreasing the overall costs. Despite the development of analgesics, the use of opioids and their derivates remains the cornerstone of treatment for patients with acute moderate-to-severe pain in association with general or regional anesthesia. To reduce the risk of side effects and opioid addiction, considering the alarming epidemiological reports in relation to opioid abuse, combined analgesic methods are used, in addition to lower dosages or different forms of administration, such as transdermal administration. Fentanyl transdermal patches appear to be effective in controlling postoperative pain as part of multimodal analgesic regimens in knee and hip surgery, shoulder arthroplasty, traumatic fractures, and one-day surgery; this treatment has fewer associated side effects and can be safely used even in patients with renal impairment. It is also recommended for postoperative pain management in combination with a femoral-sciatic nerve block during foot and ankle surgery.

Total Antioxidant Status in Critically Ill Patients with Traumatic Brain Injury and Secondary Organ Failure-A Systematic Review

Introduction: The available literature indicates that oxidant-antioxidant imbalance plays a significant role in the pathophysiology of traumatic brain injury and the subsequent secondary organ dysfunctions. However, there is a lack of studies summarizing the knowledge in this area, and no clear guidelines exist regarding the use of biomarkers of oxidative stress as diagnostics tools. Methods: The present work aims to provide a systematic review of the literature on the use of total antioxidant capacity (TAC) assays in predicting the outcomes of traumatic brain injury (TBI). A literature search was conducted up to 1 September 2024, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) guidelines, using the PubMed and Scopus databases. Based on the inclusion criteria, 24 studies were used for the final review. Results: Promising data indicate that TAC assays are useful in predicting 30-day mortality and neurological outcomes. Moreover, they correlate with radiological findings on CT scans in brain injury and the clinical classifications of injuries, as well as the parameters of organ failure. Conclusions: Total antioxidant capacity assays can be used to assess the extent of brain damage and prognosticate general vital functions. Future experiments should include long-term randomized clinical trials on larger populations of TBI patients.

Risk of infections among persons treated with opioids for chronic pain: a systematic review and meta-analysis protocol

INTRODUCTION

Millions of persons with chronic pain across North America and Europe use opioids. While the immunosuppressive properties of opioids are associated with risks of infections, these outcomes could be mitigated through careful patient selection and monitoring practices when appropriate. It is important to recognise that some patients do benefit from a carefully tailored opioid therapy. Enough primary studies have been published to date regarding the role of opioids in potential immunosuppression presenting as an increased rate of infection acquisition, infectious complications and mortality. There is thus a critical need for a consensus in this area.

METHODS AND ANALYSIS

The methodology is based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, the MOOSE Guidelines for Meta-Analyses and Systematic Reviews of Observational Studies and the Cochrane Handbook for Systematic Reviews of Interventions. We plan to systematically search Ovid MEDLINE, CINAHL, PsycINFO, EMB Review, EMBASE, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials and Google Scholar databases from their inception date to December 2023. Full-text primary studies that report measurable outcomes in adults with chronic pain, all routes of opioid use, all types of infections and all settings will be included. We will identify a scope of reported infections and the evidence on the association of opioid use (including specific opioid, dosage, formulation and duration of use) with the risk of negative infectious outcomes. Opioid use-associated outcomes, comparing opioid use with another opioid or a non-opioid medication, will be reported. The meta-analysis will incorporate individual risk factors. If data are insufficient, the results will be synthesised narratively. Publication bias and confounding evaluation will be performed. The Grading of Recommendations Assessment, Development and Evaluation framework will be used.

ETHICS AND DISSEMINATION

Approval for the use of published data is not required. The results will be published, presented at conferences and discussed in deliberative dialogue groups.

PROSPERO REGISTRATION NUMBER

CRD42023402812.

Opioids and Cannabinoids in Neurology Practice

OBJECTIVE

Opioid and cannabinoid therapies for chronic pain conditions including neuropathic pain are controversial. Understanding patient and prescribing factors contributing to risks and implementing risk mitigation strategies optimizes outcomes.

LATEST DEVELOPMENTS

The ongoing transformation from a biomedical model of pain care toward a biopsychosocial model has been accompanied by a shift away from opioid therapy for pain, in particular for chronic pain. Opioid overdose deaths and opioid use disorder have greatly increased in the last several decades, initially because of increases in opioid prescribing and more recently associated with illicit drug use, in particular fentanyl derivatives. Opioid risk mitigation strategies may reduce risks related to opioid prescribing and tapering or discontinuation. Opioid therapy guidelines from the Centers for Disease Control and Prevention have become the consensus best practice for opioid therapy. Regulatory agencies and licensing medical boards have implemented restrictions and other mandates regarding opioid therapy. Meanwhile, interest in and use of cannabinoids for chronic pain has grown in the United States.

ESSENTIAL POINTS

Opioid therapy is generally not recommended for the chronic treatment of neuropathic pain conditions. Opioids may be considered for temporary use in patients with severe pain related to selected neuropathic pain conditions (such as postherpetic neuralgia), and only as part of a multimodal treatment regimen. Opioid risk mitigation strategies include careful patient selection and evaluation, patient education and informed consent, querying the state prescription drug monitoring programs, urine drug testing, and issuance of naloxone as potential rescue medication. Close follow-up when initiating or adjusting opioid therapy and frequent reevaluation during long-term opioid therapy is required. There is evidence for the efficacy of cannabinoids for neuropathic pain, with meaningful response rates in select patient populations.

Understanding the impact of the gut microbiome on opioid use disorder: Pathways, mechanisms, and treatment insights

The widespread use of opioids for chronic pain management not only poses a significant public health issue but also contributes to the risk of tolerance, dependence, and addiction, leading to opioid use disorder (OUD), which affects millions globally each year. Recent research has highlighted a potential bidirectional relationship between the gut microbiome and OUD. This emerging perspective is critical, especially as the opioid epidemic intensifies, emphasizing the need to investigate how OUD may alter gut microbiome dynamics and vice versa. Understanding these interactions could reveal new insights into the mechanisms of addiction and tolerance, as well as provide novel approaches for managing and potentially mitigating OUD impacts. This comprehensive review explores the intricate bidirectional link through the gut-brain axis, focusing on how opiates influence microbial composition, functional changes, and gut mucosal integrity. By synthesizing current findings, the review aims to inspire new strategies to combat the opioid crisis and leverage microbiome-centred interventions for preventing and treating OUD.

Shared and unique 3D genomic features of substance use disorders across multiple cell types

Recent genome-wide association studies (GWAS) have revealed shared genetic components among alcohol, opioid, tobacco and cannabis use disorders. However, the extent of the underlying shared causal variants and effector genes, along with their cellular context, remain unclear. We leveraged our existing 3D genomic datasets comprising high-resolution promoter-focused Capture-C/Hi-C, ATAC-seq and RNA-seq across >50 diverse human cell types to focus on genomic regions that coincide with GWAS loci. Using stratified LD regression, we determined the proportion of genomewide SNP heritability attributable to the features assayed across our cell types by integrating recent GWAS summary statistics for the relevant traits: alcohol use disorder (AUD), tobacco use disorder (TUD), opioid use disorder (OUD) and cannabis use disorder (CanUD). Statistically significant enrichments (P<0.05) were observed in 14 specific cell types, with heritability reaching 9.2-fold for iPSC-derived cortical neurons and neural progenitors, confirming that they are crucial cell types for further functional exploration. Additionally, several pancreatic cell types, notably pancreatic beta cells, showed enrichment for TUD, with heritability enrichments up to 4.8-fold, suggesting genomic overlap with metabolic processes. Further investigation revealed significant positive genetic correlations between T2D with both TUD and CanUD (FDR<0.05) and a significant negative genetic correlation with AUD. Interestingly, after partitioning the heritability for each cell type's cis-regulatory elements, the correlation between T2D and TUD for pancreatic beta cells was greater (r=0.2) than the global genetic correlation value. Our study provides new genomic insights into substance use disorders and implicates cell types where functional follow-up studies could reveal causal variant-gene mechanisms underpinning these disorders.

Pharmacogenetic landscape of pain management variants among Mediterranean populations

Background

Chronic pain is a major socioeconomic burden in the Mediterranean region. However, we noticed an under-representation of these populations in the pharmacogenetics of pain management studies. In this context, we aimed 1) to decipher the pharmacogenetic variant landscape among Mediterranean populations compared to worldwide populations in order to identify therapeutic biomarkers for personalized pain management and 2) to better understand the biological process of pain management through in silico investigation of pharmacogenes pathways.

Materials and Methods

We collected genes and variants implicated in pain response using the Prisma guidelines from literature and PharmGK database. Next, we extracted these genes from genotyping data of 829 individuals. Then, we determined the variant distribution among the studied populations using multivariate (MDS) and admixture analysis with R and STRUCTURE software. We conducted a Chi2 test to compare the interethnic frequencies of the identified variants. We used SNPinfo web server, miRdSNP database to identify miRNA-binding sites. In addition, we investigated the functions of the identified genes and variants using pathway enrichment analysis and annotation tools. Finally, we performed docking analysis to assess the impact of variations on drug interactions.

Results

We identified 63 variants implicated in pain management. MDS analysis revealed that Mediterranean populations are genetically similar to Mexican populations and divergent from other populations. STRUCTURE analysis showed that Mediterranean populations are mainly composed of European ancestry. We highlighted differences in the minor allele frequencies of three variants (rs633, rs4680, and rs165728) located in the COMT gene. Moreover, variant annotation revealed ten variants with potential miRNA-binding sites. Finally, protein structure and docking analysis revealed that two missense variants (rs4680 and rs6267) induced a decrease in COMT protein activity and affinity for dopamine.

Conclusion

Our findings revealed that Mediterranean populations diverge from other ethnic groups. Furthermore, we emphasize the importance of pain-related pathways and miRNAs to better implement these markers as predictors of analgesic responses in the Mediterranean region.

Opioid Prescription and Long-Term Survival Outcomes in Adults: A Nationwide Cohort Study in Korea

BACKGROUND

We aimed to investigate the association between short- and long-term opioid use and long-term mortality in Korea.

METHODS

In this population-based retrospective cohort study, data were obtained from the National Health Insurance Service of South Korea. The study included all adult individuals who were prescribed opioids in 2016. The control group comprised adults not prescribed opioids in 2016 selected using a 1:1 stratified random sampling technique. Participants were categorized into three groups: non-user, opioid 1-89 days user (short-term), and opioid ≥ 90 days user (long-term) groups. The primary endpoint in this study was 5-year all-cause mortality, evaluated from January 1, 2017 to December 31, 2021.

RESULTS

In total, 4,556,606 adults were included in this study. Of these, 2,070,039 were prescribed opioids at least once. Specifically, 1,592,883 adult individuals were prescribed opioids for 1-89 days, while 477,156 adults were prescribed opioid for ≥ 90 days. In the multivariable Cox regression modelling, the opioid user group had a 28% (hazard ratio [HR], 1.28; 95% confidence interval [95% CI], 1.26-1.29; P < 0.001) higher risk of 5-year all-cause mortality than had the non-user group. Moreover, the opioid 1-89 days and opioid ≥ 90 days user groups had 15% (HR, 1.15; 95% CI, 1.14-1.17; P < 0.001) and 49% (HR, 1.49; 95% CI, 1.47-1.51; P < 0.001) higher risks of 5-year all-cause mortality than had the non-user group, respectively.

CONCLUSION

Both short and long-term opioid prescriptions were associated with increased long-term mortality among the Korean adult population.

Are There Any Advantages of the Low Opioid Anaesthesia and Non-Opioid Postoperative Analgesia Protocol: A Clinical Observational Study

Purpose

The methods of perioperative analgesia and pain control have changed. The principle of opioid-based analgesia has been modified to multimodal analgesia, followed by LOA (low opioid anaesthesia) and OFA (opioid-free anaesthesia). The aim was to describe the effects of LOA on nausea, vomiting, and pain control during general anaesthesia and postoperative period after laparoscopic cholecystectomy.

Patients and Methods

The protocol included the study group-40 patients received low-opioid anaesthesia (LOA), and the control group-40 patients received general anaesthesia with opioid analgesia (OA). The scheme of LOA was based on ketamine, lidocaine, magnesium sulfate, paracetamol, and metamizole. The OA was based on standard opioid (fentanyl) administration in induction and maintenance phase due to clinical observation. Postoperative analgesia included 1g of paracetamol and 1g of metamizol intravenously, with a 6-hour interval between doses.

Results

Significant differences in the pain score in the periods of 2-6, 6-12, and 12-24 hours after anaesthesia between the groups were noticed (p < 0.001). Moreover, a significant difference in the frequency of nausea (p = 0.005) and vomiting (p = 0.04) between groups were presented. Nausea occurred in 54.05% of OA group, while in the LOA group, it occurred in a 23.08%. Vomiting occurred in 32.43% of control group, while in the study group, it occurred in 12.82% of patients.

Conclusion

The LOA protocol was more beneficial in reducing nausea and vomiting than the opioid-based method of anaesthesia. The LOA protocol of general anaesthesia during laparoscopic cholecystectomy and non-opioid postoperative analgesia have better outcomes in pain control, as well as nausea and vomiting, and improve postoperative patient comfort. The LOA protocol during anaesthesia and non-opioid postoperative analgesia should be considered in routine practice.

Trends in Healthy Life Expectancy (HALE) and Disparities by Income and Region in Korea (2008-2020): Analysis of a Nationwide Claims Database

BACKGROUND

Healthy life expectancy is a well-recognized indicator for establishing health policy goals used in Korea's Health Plan. This study aimed to explore Koreans' healthy life expectancy and its gender, income, and regional disparities from 2008 to 2020.

METHODS

This study was conducted on the entire population covered by health insurance and medical aid program in Korea. The incidence-based "years lived with disability" for 260 disease groups by gender, income level, and region was calculated employing the methodology developed in the Korean National Burden of Disease Study, and it was used as the number of healthy years lost to calculate health-adjusted life expectancy (HALE).

RESULTS

Koreans' HALE increased from 68.89 years in 2008 to 71.82 years in 2020. Although the gender disparity in HALE had been decreasing, it increased to 4.55 years in 2020. As of 2020, 5.90 years out of 8.67 years of the income disparity (Q5-Q1) in HALE were due to the disparity between Q1 and Q2, the low-income groups. Income and regional disparities in HALE exhibited an increasing trend, and these disparities were higher in men than in women.

CONCLUSION

A subgroup with a low health level was identified through the HALE results, and it was confirmed that improving the health level of this population can reduce health inequalities and improve health at the national level. Further exploration of the HALE calculation methodology may help in the development of effective policies such as prioritizing interventions for health risk factors.

The effects of OPRM1 118A>G on methadone response in pain management in advanced cancer at end of life

Cancer pain is the most feared symptom at end of life. Methadone has advantages over other opioids but is associated with significant variability in clinical response, making dosing challenging in practice. OPRM1 is the most studied pharmacogene associated with the pharmacodynamics of opioids, however reports on the association of the A118G polymorphism on opioid dose requirements are conflicting, with no reports including methadone as the primary intervention. This association study on OPRM1 A118G and response to methadone for pain management, includes a review of this genetic factor's role in inter-patient variability. Fifty-four adult patients with advanced cancer were recruited in a prospective, multi-centre, open label dose individualization study. Patient characteristics were not shown to influence methadone response, and no significant associations were observed for methadone dose or pain score. The findings of our review of association studies for OPRM1 A118G in advanced cancer pain demonstrate the importance of taking ancestry into account. While our sample size was small, our results were consistent with European populations, but in contrast to studies in Chinese patients, where carriers of the A118G polymorphism were associated with higher opioid dose requirements. Pharmacogenetic studies in palliative care are challenging, continued contribution will support future genotype-based drug dosing guidelines.

Opioid Therapy and Implications for Oxidative Balance: A Clinical Study of Total Oxidative Capacity (TOC) and Total Antioxidative Capacity (TAC)

BACKGROUND

Opioids are used in pharmacotherapy for chronic pain. The phenomenon of their influence on the oxidative-antioxidant balance is poorly understood. Additionally, little is known about the oxidative status in patients receiving chronic opioid noncancer pain therapy.

METHODS

The primary goal was to explore oxidative status using the total oxidative capacity (TOC) and total antioxidative capacity (TAC) in patients with chronic lower back pain (LBP) treated with opioids. The secondary task was to present the risk factors connected with the duration of therapy or anthropometric parameters. Plasma TOC and TAC were analyzed in the study group (n = 28), i.e., patients with chronic LBP treated with opioids, and in the control group (n = 11), i.e., healthy volunteers.

RESULTS

The TAC was significantly lower in the study group compared to the control group (p < 0.05), while the TOC did not differ significantly. A statistically lower TOC for buprenorphine compared to oxycodone (p = 0.019) and tramadol (p = 0.036) was observed. The TOC did not differ between tramadol and oxycodone. The highest TAC was described for oxycodone, while the TAC for buprenorphine and tramadol was significantly lower in comparison with oxycodone (p = 0.007 and p = 0.016). The TOC/TAC ratio was higher in patients with nicotinism in both groups.

CONCLUSIONS

Patients receiving chronic opioid therapy presented a lower antioxidative capacity. There were differences in opioid-induced oxidative imbalance, which is very important clinically. Nicotinism increases the oxidative-antioxidative imbalance. The least oxidative capacity was associated with buprenorphine, while oxycodone showed the greatest antioxidant activity. The most favorable TOC/TAC ratio was observed for buprenorphine. It is suggested that buprenorphine or oxycodone has the best profile, and there is no correlation with the duration of opioid therapy or the opioid dose. However, all opioid substances can potentially enhance the oxidative-antioxidative status.

Mu and Kappa opioid receptor immunolabeling indicates the prognosis of oropharyngeal squamous cell carcinoma: A cross-sectional observational study

BACKGROUND

Opioids are the most effective drugs currently available for cancer pain management. The administration of morphine, in addition to its analgesic effect, can alter tumor development.

OBJECTIVE

To characterize the immunoexpression of opioid receptors µ and κ in oropharyngeal squamous cell carcinoma, and correlate it with prognostic factors, proliferation markers, and cell death.

MATERIALS AND METHODS

A retrospective, cross-sectional observational study was carried out with 50 patients diagnosed at Haroldo Juaçaba Hospital. Sociodemographic, clinicopathological, and overall survival data were collected, and excisional biopsies were taken for immunohistochemistry using tissue microarrays for opioid receptors µ and κ, Ki-67, and caspase-3. Immunolabeling was evaluated and correlated with other variables using Mann-Whitney, Kruskal-Wallis, Spearman correlation, log-rank (Mantel-Cox), and Cox regression tests.

RESULTS

Immunoexpression of opioid receptors µ and κ, Ki-67, and caspase-3 was significantly higher in p16+ and p16- primary tumors and lymph node metastases than in surgical resection margins. The overall survival of patients with p16- tumors was 57.53 ± 8.43 months and that of patients with p16+ tumors was slightly higher at 75.92 ± 11.14 months. Multivariate analysis showed that the expression of opioid receptors µ and κ in the nucleus was directly associated with a lower and higher risk of death, respectively.

CONCLUSION

We found increased expression of opioid receptors µ and κ in tumor tissues. The nuclear expression of opioid receptors µ and κ influences overall survival and may be a prognostic factor of oropharyngeal squamous cell carcinoma.

Perioperative Challenges of Heroin Addiction: A Case Report of Opioid-Free Anesthesia in Tongue Carcinoma Excision With Free-Flap Reconstruction

Anesthesia for major head and neck surgery is historically heavily reliant on opioids with deleterious consequences. We reported a case of a patient with a history of heroin abuse submitted to a tongue carcinoma excision, followed by free-flap reconstruction under opioid-free anesthesia. We used a propofol total intravenous anesthesia and perfusions of ketamine, dexmedetomidine, lidocaine, and magnesium sulfate for analgesia, complemented by boluses of dexamethasone, acetaminophen, parecoxib, and metamizole. Hemodynamic needs of the procedure were addressed by titrating perfusions of sodium nitroprusside or dobutamine. The patient was weaned from the ventilator at the end of the surgery. Surgical outcomes were achieved and opioid-free analgesia allowed early reestablishment of bodily functions without compromise of adequate pain control. Anesthesia protocols for free-flap surgery still lack scientific evidence, especially in the context of substance abuse: opioid-sparing approaches seem a viable option, which requires further studies and familiarity by health care professionals.

Promoter Methylation of Two HOXA9 and NISCH Genes in Opium Users

BACKGROUND

Opiate abuse has been critically increased in the world, especially in Iran. Owing to the association of opiate use with multiple human cancers and neurological disorders, seeking for genetic and epigenetic effects of opium can pave the way for early diagnosis of major health defects in addicted users. Accordingly, the present study aimed to determine the methylation status of the promoter of two genes, which are actively involved in neurodevelopment and cancer evolution.

METHODS

DNA was isolated from peripheral blood of 28 opium abusers and 19 healthy controls and then subjected to sonication. Sonicated DNAs undergone methylated DNA immunoprecipitation-real time polymerase chain reaction (MeDIP-Real Time PCR) using specific primer pairs designed for HOXA9 and NISCH genes. Obtained data were analyzed using SPSS software.

FINDINGS

HOXA9 and NISCH genes were found to be significantly methylated in addicted users compared to controls (P<0.001) which was significantly associated with the mean of the age regarding HOXA9 gene (P=0.002). Neither opium amount nor duration or route of using was associated with the methylation status of HOXA9 or NISCH genes.

CONCLUSION

Hypermethylation of HOXA9 and NISCH genes as tumor suppressor in opium-addicted individuals can be considered as confirmatory evidence for carcinogenesis of opium. Further studies are required to figure out the role of epigenetic alterations in cancer evolution among opium users.

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.

Dezocine Has the Potential to Regulate the Clinical and Biological Features of Tumors

Cancer is the second leading cause of death following ischemic heart disease in the world and the primary clinical, social and economic burden. Surgical resection is the main measure for the treatment of the vast majority of solid tumors. However, the recurrence and metastasis of tumors occur at different periods after surgery in many cases undergoing radical tumor surgery, which is the main cause of death of tumor patients. Moreover, tumor patients are prone to suffer from mental depression, which may increase the morbidity and mortality of tumors. Tumors have a series of clinical biological signs with the following five main features: postoperative pain and cancerous pain; suppression of antitumor immunity; angiogenesis in tumors; proliferation, growth and metastasis of tumors; and mental depression. Surgery is the first treatment in the majority of cancer patients with solid tumors. Opioids are required for anesthesia and postoperative analgesia. For cancerous pain control, patients undergo surgery, and their quality of life of is improved. However, traditional opioids, such as morphine, may inhibit antitumor immunity, induce vascular growth of tumors and promote the proliferation, invasion and migration of cancer cells, and traditional opioids can induce a risk of somatic dependence. However, studies have found that not all opioids share the effects of immunosuppression, tumor proliferation promotion and angiogenesis induction. Dezocine, a novel opioid with specific pharmacological mechanisms, has been demonstrated to regulate the five clinical and biological features of tumors. We reviewed the preclinical and clinical studies of dezocine on postoperative pain and cancer pain in tumor patients as well as the immune system, tumor angiogenesis, tumor proliferation, tumor growth, tumor metastasis and mental depression. We proposed that dezocine may be the best choice of opioids for anesthesia and analgesia in cancer patients.

The Interplay between Chronic Pain, Opioids, and the Immune System

Chronic pain represents one of the most serious worldwide medical problems, in terms of both social and economic costs, often causing severe and intractable physical and psychological suffering. The lack of biological markers for pain, which could assist in forming clearer diagnoses and prognoses, makes chronic pain therapy particularly arduous and sometimes harmful. Opioids are used worldwide to treat chronic pain conditions, but there is still an ambiguous and inadequate understanding about their therapeutic use, mostly because of their dual effect in acutely reducing pain and inducing, at the same time, tolerance, dependence, and a risk for opioid use disorder. In addition, clinical studies suggest that opioid treatment can be associated with a high risk of immune suppression and the development of inflammatory events, worsening the chronic pain status itself. While opioid peptides and receptors are expressed in both central and peripheral nervous cells, immune cells, and tissues, the role of opioids and their receptors, when and why they are activated endogenously and what their exact role is in chronic pain pathways is still poorly understood. Thus, in this review we aim to highlight the interplay between pain and immune system, focusing on opioids and their receptors.

Potential Therapeutic Benefit of Low Dose Naltrexone in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Role of Transient Receptor Potential Melastatin 3 Ion Channels in Pathophysiology and Treatment

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating multi-systemic chronic condition of unknown aetiology classified as an immune dysfunction syndrome and neurological disorder. The discovery of the widely expressed Transient Receptor Potential Melastatin 3 (TRPM3) as a nociceptor channel substantially targeted by certain opioid receptors, and its implication in calcium (Ca²⁺)-dependent Natural Killer (NK) cell immune functions has raised the possibility that TRPM3 may be pharmacologically targeted to treat characteristic symptoms of ME/CFS. Naltrexone hydrochloride (NTX) acts as an antagonist to the mu (μ)-opioid receptor thus negating its inhibitory function on TRPM3. Based on the benefits reported by patients on their symptoms, low dose NTX (LDN, 3.0-5.0 mg/day) treatment seems to offer some potential benefit suggesting that its effect may be targeted towards the pathomechanism of ME/CFS. As there is no literature confirming the efficacy of LDN for ME/CFS patients in vitro, this study investigates the potential therapeutic effect of LDN in ME/CFS patients. TRPM3 ion channel activity was measured after modulation with Pregnenolone sulfate (PregS) and ononetin in NK cells on 9 ME/CFS patients taking LDN and 9 age- and sex-matched healthy controls using whole-cell patch-clamp technique. We report that ME/CFS patients taking LDN have restored TRPM3-like ionic currents in NK cells. Small ionic currents with a typical TRPM3-like outward rectification were measured after application of PregS, a TRPM3-agonist, in NK cells from patients taking LDN. Additionally, PregS-evoked ionic currents through TRPM3 were significantly modulated by ononetin, a TRPM3-antagonist, in NK cells from ME/CFS patients taking LDN. These data support the hypothesis that LDN may have potential as a treatment for ME/CFS by characterising the underlying regulatory mechanisms of LDN treatment involving TRPM3 and opioid receptors in NK cells. Finally, this study may serve for the repurpose of marketed drugs, as well as support the approval of prospective randomized clinical studies on the role and dose of NTX in treating ME/CFS patients.

Does COVID19 activates previous chronic pain? A case series

Introduction

With the outbreak of coronavirus, the number of patients who referred to the pain clinic for follow-up was much higher than before, which coincided with the onset of the coronavirus pandemic. However, due to incomplete knowledge regarding the virus and its effects, patients did not follow up to the pain.

Methods

We present case of 8 patients who were treated previously for chronic pain (complete remission).

Results

During the pandemic, these patients were presented to our center presenting identical pain, that did not respond to the conservative therapy. Owing to the symptoms, these patients were screened and tested positive for COVID19. Two of the patients died whereas, symptoms were improved in other patients.

Conclusion

Patients with the history of chronic pain may present relapse as a result of the infection or infection can trigger previous chronic pain among patients with risk factors.

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Coronavirus disease 2019 (COVID19), caused by new coronavirus.

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Due to incomplete knowledge regarding the virus and its effects, patients did not follow up to the pain.

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Patients with the history of chronic pain may present relapse.

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Infection can trigger previous chronic pain among patients with risk factors.

How to Restart the Interventional Activity in the COVID-19 Era: The Experience of a Private Pain Unit in Spain

INTRODUCTION

The situation generated in the health system by the COVID-19 pandemic has provoked a crisis involving the necessity to cancel non-urgent and oncologic activity in the operating room and in day-to-day practice. As the situation continues, the need to reinstate attention for patients with chronic pain grows. The restoration of this activity has to begin with on-site appointments and possible surgical procedures. On-site clinical activity has to guarantee the safety of patients and health workers.

OBJECTIVES

The objective of this review was to evaluate how to manage activity in pain units, considering the scenario generated by the pandemic and the implications of chronic pain on the immune system and proposed pharmacological and interventional therapies.

METHODS

Besides the established general recommendations (physical distance, surgical masks, gloves, etc.), we established specific recommendations that will allow patient treatment and relieve the disruption of the immune response. It is important to highlight the use of opioids with the least influence in the immune system. Further, individualized corticoid use, risk assessment, reduced immune suppression, and dose adjustment should take patient needs into account. In this scenario, we highlight the use of radiofrequency and neuromodulation therapies, techniques that do not interfere with the immune response.

CONCLUSIONS

We describe procedures to implement these recommendations for individual clinical situations, the therapeutic possibilities and safety guidelines for each center, and government recommendations during the COVID-19 pandemic.