Opioid therapy and immunosuppression: a review

The effect of COVID-19 on pain control in patients with a neurostimulator in situ- a retrospective study

BACKGROUND

De-novo chronic neuropathic pain following COVID-19 is widely recognised. However, there are currently no published studies investigating the effect of SARS-CoV-2 infection on patients with pre-existing neuropathic pain who have required spinal cord stimulator (SCS) implantation. Here, the authors aimed to analyse outcomes in their institution's patients who had spinal cord stimulator (SCS) implantation or revision procedures to the system over a 5-year period. Specifically, the short-term and long-term outcomes of patients who contracted COVID-19 during the follow-up period were compared to the control group of patients who did not.

METHOD

Patients included in this study had spinal cord stimulator implantation (de-novo and revision procedures) between 1 January 2017 and 31 January 2022, for neuropathic pain of any aetiology. Patients deemed eligible for the study were invited to participate in a telephone survey through which clinical outcome data were collected. Pain scores were assessed with a modified form of the Brief Pain Inventory (BPI).

RESULTS

Of 91 patients, 48 (52.7%) had contracted COVID-19 by the time of the survey. Patients who contracted COVID-19 had significantly worse BPI scores in the 'Least pain' domain following their infection and at time of the survey, when compared to their score 6 months after the operation. 22.9% (n = 11) of the patients who contracted COVID-19 experienced a change in their symptoms following their infection. Within this sub-group, there was a statistically significant deterioration in BPI scores in 10/11 domains following their infection and in 2/11 domains at time of the survey. Worsening severity of COVID-19 symptoms was not associated with worse BPI scores.

CONCLUSIONS

Infection with SARS-CoV-2, in a significant proportion of patients with an SCS in situ, causes at least a transient deterioration in pain control. Further prospective multicentre studies are indicated to establish the prevalence of this phenomenon.

Effect of Intraoperative Opioid Dose on Perioperative Neutrophil-to-Lymphocyte Ratio and Lymphocyte-to-Monocyte Ratio in Glioma

Background

The neutrophil-to-lymphocyte ratio (NLR) and lymphocyte-to-monocyte ratio (LMR) are inflammatory biomarkers. Until now, it is unknown the impact of opioid dosage on perioperative immunity in glioma patients. The aim of this study was to explore the effect of intraoperative opioid dosage on perioperative immune perturbations using NLR and LMR as inflammatory biomarkers and evaluate the correlation between inflammatory biomarkers and pathological grade of glioma.

Methods

The study included 208 patients with primary glioma who underwent glioma resection from February 2012 to November 2019 at Harbin Medical University Cancer Hospital. Complete blood count (CBC) was collected at 3 time points: one week before surgery, and 24 hours and one week after surgery. Patients were divided into high-dose and low-dose groups, based on the median value of intraoperative opioid dose. The relationships between perioperative NLR, LMR and intraoperative opioid dosage were analyzed using repeated measurement analysis of variance (ANOVA). Correlations between preoperative various factors and pathological grade were analyzed by Spearman analysis. Receiver operating characteristic (ROC) curves were performed to assess the predictive performance of the NLR and LMR for pathological grade.

Results

The NLR (P=0.020) and lower LMR (P=0.037) were statistically significant different between high-dose and low-dose groups one week after surgery. The area under the curve (AUC) of the NLR to identify poor diagnosis was 0.685, which was superior to the LMR (AUC: 0.607) and indicated a correlation between the NLR with pathological grade. The preoperative NLR (P=0.000), LMR (P=0.009), age (P=0.000) and tumor size (P=0.001) exhibited a significant correlation with the pathological grade of glioma.

Conclusion

Intraoperative opioids in the high-dose group were associated with higher NLR and lower LMR in postoperative glioma patients. The preoperative NLR and LMR demonstrated predictive value for distinguishing between high-grade and low-grade gliomas.

Opioid prescription and risk of atrial fibrillation in younger veterans

BACKGROUND

Opioids may play a part in the development of atrial fibrillation (AF). Understanding the relationship between opioid exposure and AF can help providers better assess the risk and benefits of prescribing opioids.

OBJECTIVE

To assess the incidence of AF as a function of prescribed opioids and opioid type.

DESIGN

We performed unadjusted and adjusted time-updated Cox regressions to assess the association between opioid exposure and incident AF.

PARTICIPANTS

The national study sample was comprised of Veterans enrolled in the Veterans Health Administration (VHA) who served in support of post-9/11 operations.

MAIN MEASURES

The main predictor of interest was prescription opioid exposure, which was treated as a time-dependent variable. The first was any opioid exposure (yes/no). Secondary was opioid type. The outcome, incident AF, was identified through ICD-9-CM diagnostic codes at any primary care visit after the baseline period.

KEY RESULTS

A total of 609,763 veterans (mean age: 34 years and 13.24% female) were included in our study. Median follow-up time was 4.8 years. Within this cohort, 124,395 veterans (20.40%) were prescribed an opioid. A total of 1,455 Veterans (0.24%) were diagnosed with AF. In adjusted time-updated Cox regressions, the risk of incident AF was higher in the veterans prescribed opioids (hazard ratio [HR]: 1.47; 95% confidence interval [CI]: 1.38-1.57). In adjusted time-updated Cox regressions, both immunomodulating and nonimmunomodulating opioid type was associated with increased risk of incident AF (HR: 1.40; 95% CI: 1.25-1.57 and HR: 1.49; 95% CI: 1.39-1.60), compared to no opioid use, respectively.

CONCLUSIONS

Our findings suggest opioid prescription may be a modifiable risk factor for the development of AF.

Opioid trail: Tracking contributions to opioid use disorder from host genetics to the gut microbiome

Opioid use disorder (OUD) is a worldwide public health crisis with few effective treatment options. Traditional genetics and neuroscience approaches have provided knowledge about biological mechanisms that contribute to OUD-related phenotypes, but the complexity and magnitude of effects in the brain and body remain poorly understood. The gut-brain axis has emerged as a promising target for future therapeutics for several psychiatric conditions, so characterizing the relationship between host genetics and the gut microbiome in the context of OUD will be essential for development of novel treatments. In this review, we describe evidence that interactions between host genetics, the gut microbiome, and immune signaling likely play a key role in mediating opioid-related phenotypes. Studies in humans and model organisms consistently demonstrated that genetic background is a major determinant of gut microbiome composition. Furthermore, the gut microbiome is susceptible to environmental influences such as opioid exposure. Additional work focused on gene by microbiome interactions will be necessary to gain improved understanding of their effects on OUD-related behaviors.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

Immunomodulatory properties of morphine and the hypothesised role of long-term opioid use in the immunopathogenesis of tuberculosis

Epidemiological studies have shown high tuberculosis (TB) prevalence among chronic opioid users. Opioid receptors are found on multiple immune cells and immunomodulatory properties of opioids could be a contributory factor for ensuing immunosuppression and development or reactivation of TB. Toll-like receptors (TLR) mediate an immune response against microbial pathogens, including Mycobacterium tuberculosis. Mycobacterial antigens and opioids co-stimulate TLRs 2/4/9 in immune cells, with resulting receptor cross-talk via multiple cytosolic secondary messengers, leading to significant immunomodulatory downstream effects. Blockade of specific immune pathways involved in the host defence against TB by morphine may play a critical role in causing tuberculosis among chronic morphine users despite multiple confounding factors such as socioeconomic deprivation, Human immunodeficiency virus co-infection and malnutrition. In this review, we map out immune pathways involved when immune cells are co-stimulated with mycobacterial antigens and morphine to explore a potential immunopathological basis for TB amongst long-term opioid users.

Opium, phencyclidine, and crack cocaine smoking associations with lung and upper aerodigestive tract cancers: exploratory findings from a case-control study in Los Angeles County

Background: Illicit drug use has become a global epidemic, yet it is unclear if drug smoking increases the risk of tobacco-related cancers.Objectives: We aimed to evaluate hypothesized associations between smoking three drugs - opium, phencyclidine (PCP) and crack cocaine and lung and upper aerodigestive tract (UADT) cancers.Methods: A population-based case-control study with 611 lung cancer cases (50% male), 601 UADT cancers cases (76% male), and 1,040 controls (60% male) was conducted in Los Angeles County (1999-2004). Epidemiologic data including drug smoking histories were collected in face-to-face interviews. Associations were estimated with logistic regressions.Results: Adjusting for potential confounders, ever vs. never crack smoking was positively associated with UADT cancers (aOR = 1.56, 95% CI: 1.05, 2.33), and a dose-response relationship was observed for lifetime smoking frequency (p for trend = .024). Heavy (> median) vs. never crack smoking was associated with UADT cancers (aOR = 1.81, 95% CI: 1.07, 3.08) and lung cancer (aOR = 1.58, 95% CI: 0.88, 2.83). A positive association was also observed between heavy PCP smoking and UADT cancers (aOR = 2.29, 95% CI: 0.91, 5.79). Little or no associations were found between opium smoking and lung cancer or UADT cancers.Conclusion: The positive associations between illicit drug use and lung and/or UADT cancers suggest that smoking these drugs may increase the risk of tobacco-related cancers. Despite the low frequency of drug smoking and possible residual confounding, our findings may provide additional insights on the development of lung and UADT cancers.

Effect of intraoperative dexmedetomidine on long-term survival in older patients after major noncardiac surgery: 3-year follow-up of a randomized trial

STUDY OBJECTIVE

To assess the impact of intraoperative dexmedetomidine on long-term outcomes of older patients following major noncardiac surgery mainly for cancer.

DESIGN

A long-term follow-up of patients enrolled in a randomized trial.

SETTING

The initial trial was performed in a tertiary care hospital in Beijing, China.

PARTICIPANTS

Patients aged 60 years or older who were scheduled for major noncardiac surgery.

INTERVENTION

Participants were randomized to receive either dexmedetomidine (a loading dose of 0.6 μg/kg over 10 min, followed by a continuous infusion of 0.5 μg/kg/h until 1 h before end of surgery) or placebo during anesthesia.

MEASUREMENTS

The primary endpoint was overall survival. Secondary endpoints included recurrence-free survival and event-free survival. Cox proportional hazard models were used to adjust for predefined confounding factors. Propensity score matching was employed for sensitive analysis.

RESULTS

Among 620 patients who were randomized in the initial trial, 619 were included in the long-term analysis (mean age 69 years, 40% female, 77% oncological surgery). The median follow-up duration was 42 months (interquartile range 41 to 45). Overall survival did not differ between the two groups: there were 49/309 (15.9%) deaths with dexmedetomidine versus 63/310 (20.3%) with placebo (adjusted hazard ratio [HR] 0.78, 95% CI 0.53-1.13, P = 0.187). Recurrence-free survival was improved with dexmedetomidine (68/309 [22.0%] events with dexmedetomidine versus 98/310 [31.6%] with placebo; adjusted HR 0.67, 95% CI 0.49-0.92, P = 0.012). Event-free survival was also improved with dexmedetomidine (120/309 [38.8%] events with dexmedetomidine versus 145/310 [46.8%] with placebo; adjusted HR 0.78, 95% CI 0.61-1.00, P = 0.047). Results were similar after propensity-score matching and in the subgroup of cancer patients.

CONCLUSIONS

In older patients having major noncardiac surgery mainly for cancer, intraoperative dexmedetomidine did not improve overall survival but was associated with improved recurrence-free and event-free survivals.

Association of preoperative opioid use and postoperative complications following breast reconstruction

BACKGROUND

Previous studies in orthopedics and general surgery have linked negative patient outcomes with preoperative opioid use. In this study, we investigated the association of preoperative opioid use on breast reconstruction outcomes and quality of life (QoL).

METHODS

We reviewed our prospective registry of patients who underwent breast reconstruction for documented preoperative opioid use. Postoperative complications were recorded at 60 days after the first reconstructive surgery and 60 days after the final staged reconstruction. We used a logistic regression model to assess the association between opioid use and postoperative complications, controlling for smoking, age, laterality, BMI, comorbidities, radiation, and previous breast surgery; linear regression to analyze RAND36 scores to evaluate the impact of preoperative opioid use on postoperative QoL, controlling for the same factors; and Pearson chi-squared test to assess factors that may be associated with opioid use.

RESULTS

Of the 354 patients eligible for inclusion, 29 (8.2%) were prescribed preoperative opioids. There were no differences in opioid use by race, BMI, comorbidities, previous breast surgery, or laterality. Preoperative opioids were associated with increased odds of postoperative complications within 60 days after the first reconstructive surgery (OR: 6.28; 95% CI: 1.69-23.4; p = 0.006) and within 60 days after the final staged reconstruction (OR: 8.38; 95% CI: 1.17-59.4; p = 0.03). Among patients using opioids preoperatively, the RAND36 physical and mental scores decreased but were not statistically significant.

CONCLUSION

We found that preoperative opioid use is associated with increased odds of postoperative complications among patients who underwent breast reconstruction and may contribute to clinically significant declines in postoperative QoL.

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

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

Influence of opioid analgesia type on circulating tumor cells in open colorectal cancer surgery (POACC-1): study protocol for a prospective randomized multicenter controlled trial

BACKGROUND

Opioids and epidural analgesia are a mainstay of perioperative analgesia but their influence on cancer recurrence remains unclear. Based on retrospective data, we found that cancer recurrence following colorectal cancer surgery correlates with the number of circulating tumor cells (CTCs) in the early postoperative period. Also, morphine- but not piritramide-based postoperative analgesia increases the presence of CTCs and shortens cancer-specific survival. The influence of epidural analgesia on CTCs has not been studied yet.

METHODS

We intend to enroll 120 patients in four centers in this prospective randomized controlled trial. The study protocol has been approved by Ethics Committees in all participating centers. Patients undergoing radical open colorectal cancer surgery are randomized into epidural, morphine, and piritramide groups for perioperative analgesia. The primary outcome is the difference in the number of CTCs in the peripheral blood before surgery, on the second postoperative day, and 2-4 weeks after surgery. The number of CTCs is measured using molecular biology methods. Perioperative care is standardized, and relevant data is recorded. A secondary outcome, if feasible, would be the expression and activity of various receptor subtypes in cancer tissue. We intend to perform a 5-year follow-up with regard to metastasis development.

DISCUSSION

The mode of perioperative analgesia favorably affecting cancer recurrence would decrease morbidity/mortality. To identify such techniques, trials with long-term follow-up periods seem suboptimal. Given complex oncological therapeutic strategies, such trials likely disable the separation of perioperative analgesia effects from other factors. We believe that early postoperative CTCs presence/dynamics may serve as a sensitive marker of various perioperative interventions´ influences on cancer recurrence. Importantly, it is unbiased to the influence of long-term factors and minimally invasive. Analysis of opioid/cannabinoid receptor subtypes in cancer tissue would improve understanding of underlying mechanisms and promote personalization of treatment. We are not aware of any similar ongoing studies.

TRIAL REGISTRATION NUMBER

NCT03700411, registration date: October 3, 2018.

STUDY STATUS

recruiting.

A retrospective investigation of the relationship between neuroblastoma response to anti-GD2 monoclonal antibodies and exposure to opioids for pain management

OBJECTIVE

Recent increased awareness and research studies reflect possible associations between opioid exposure and cancer outcomes. Children with neuroblastoma (NB) often require opioid treatment for pain. However, associations between tumor response to chemotherapy and opioid exposure have not been investigated in clinical settings.

METHODS

This is a single-institution retrospective review of patients with NB treated between 2013 and 2016. We evaluated opioid consumption quantified in morphine equivalent doses (mg/kg) based on nurse- or patient-controlled analgesia during antibody infusions. We also analyzed their associations with change in primary tumor volume and total tumor burden.

RESULTS

Of 42 patients given opioids for pain related to anti-disialoganglioside monoclonal antibodies (anti-GD2 mAb), data completion was achieved for 36, and details of statistical analyses were entered. Median total weight-based morphine equivalent (over 8 days) was 4.71 mg/kg (interquartile range 3.49-7.96). We found a statistically insignificant weak negative relationship between total weight-based morphine equivalents and tumor volume ratio (correlation coefficient -.0103, p-value .9525) and a statistically insignificant weak positive relationship between total weight-based morphine equivalent and Curie score ratio (correlation coefficient .1096, p-value .5247).

CONCLUSION

Our study found no statistically significant correlation between opioid consumption and natural killer (NK) cell-mediated killing of NB cells as measured by effects on tumor volume/tumor load.

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

Background

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

Purpose

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

Methods

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

Results

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

Conclusion

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

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.

Interleukin-33 and Soluble ST2 as Potential Biomarkers of Cancer in Opium Users: A Nested Case-Control Study

BACKGROUND

Opium abuse is one of the social hazards in the Middle Eastern countries. Opium consumption attributes to various malignancies. However, the exact molecular mechanism of this correlation still remains unclear. Cancer and inflammation are closely correlated. Interleukin-33 (IL-33) and its receptors, transmembrane ST2 (ST2L) and soluble ST2 (sST2), have been significantly associated with tumorigenicity. The present study aimed to investigate whether IL-33 and sST2 levels serve as cancer biomarkers in opium users.

METHODS

Serum samples were collected from 100 opium users and 100 healthy non-opium users in a nested case-control design. The subjects with over five years of history of opium abuse were enrolled. To assess the incidence of malignancies, the opium users were followed up from 2014 to 2019. Serum levels of IL-33 and sST2 were measured using an ELISA kit. For comparison of IL-33 and sST2 levels between the groups, two-tailed Student's t test and Mann-Whitney U test were utilized, accordingly. Logistic regression analysis was performed to evaluate the influence of confounders on the incidence of cancer.

RESULTS

During the five-year follow-up, eight opium users were diagnosed with cancer. Cancer was developed by 9.3 folds in the individuals abusing opium compared to that in the non-opium users (P=0.040, OR=9.3; 95%CI [1.1-79.4]). Serum levels of IL-33 were found to be significantly higher in the opium users than those in the healthy control group (P=0.001). The sST2 levels were significantly lower in the opium users (P=0.001). The opium users with cancer exhibited significantly higher levels of IL-33 and lower levels of sST2 than the cancer-free ones (P=0.001).

CONCLUSION

Decline in sST2 levels and rise in the level of IL-33 are valuable biomarkers in predicting cancers. Regarding the significant alterations in the levels of these biomarkers in the opium users, as well as those in the opium users diagnosed with cancer, IL-33 and sST2 may serve as potential biomarkers in the early prediction of cancer.

Acupuncture Inhibits Morphine Induced-Immune Suppress via Antioxidant System

Objectives

A powerful analgesic called Morphine causes addiction behaviors and immune suppression as a potential oxidative stressor. Acupuncture showed to inhibit oxidative stress-induced hepatic damage, regulate reactive oxygen species, and attenuate morphine addiction behaviors. Therefore, we investigated the potential effects of acupuncture on morphine-induced immune suppression.

Materials and Methods

Rats received morphine intravenously through implanted catheters for 3, 7, or 21 days to determine the optimal condition for morphine-induced immune suppression. Second, we examined whether intravenous (iv.) or intraperitoneal (ip.) administration produced different results. Third, the effects of acupuncture in rats who received morphine for 21 days were investigated. Spleen and submandibular lymph node (S-LN) weights and natural killer (NK) cell activity were measured, and the white pulp diameter, total and cortical spleen thicknesses, and the number of lymphoid follicles in S-LNs were examined. The number of immunoreactive cells was also measured.

Results

Decreased organ weights and increased atrophic changes were observed as morphine-induced immune suppression. However, dose-dependent increased immune suppression was not observed between 5.0 mg/kg and 10.0 mg/kg of morphine. And, 3-day withdrawal did not affect. Similar histopathological findings were observed in 5.0 and 10.0 ip. rats when compared to equal dosages of iv., respectively. The morphine induced-immune suppression evidenced by spleen and left S-LN weights, splenic NK cell activities, histopathological findings, and the immunoreactive cell number were normalized by acupuncture.

Conclusion

These results indicate that acupuncture inhibits morphine-induced immune suppression, maybe via antioxidative action.

Opium use and risk of bladder cancer: a multi-centre case-referent study in Iran

BACKGROUND

Bladder cancer (BC) is the 10th most common type of cancer worldwide and the fourth most common type of cancer in Iran. Opium use is considered as one of the risk factors for BC. We aim to assess the association between various parameters of opium use, which in Iran is mainly ingested or smoked in various forms, and the risk of BC.

METHOD

In this multi-centre case-referent study in Iran, 717 BC cases and 3477 referents were recruited to the study from May 2017 until July 2020. Detailed histories of opium use (duration, amount, frequency) and potential confounders were collected by trained interviewers. Multivariable unconditional logistic regression models were used to measure adjusted odds ratio (OR) and 95% confidence intervals (CI). The ORs were adjusted for age, gender, place of residence and pack-years of cigarette smoking.

RESULTS

Regular opium consumption was associated with an increased risk of BC (OR 3.5, 95% CI: 2.8, 4.3) compared with subjects who never used opium. Compared with continuous users, the risk decreased to one-third for those who stopped opium more than 10 years ago. The adjusted OR for those who used both crude opium (teriak) and opium juice was 7.4 (95% CI: 4.1, 13.3). There was a joint effect of opium and tobacco (OR for users of both opium and tobacco 7.7, 95% CI: 6.0, 9.7).

CONCLUSIONS

Regular opium use is associated with an approximately 4-fold risk for BC. The OR decreases along with the increasing time since stopping opium use.

Cervical epidural abscess due to implantation of a spinal cord stimulation lead

Spinal cord stimulation (SCS) for intractable pain syndromes has become a pillar of modern pain management. Common complications include lead migration, implant infection, cerebral spinal fluid leak, and lead fracture. Spinal epidural abscess due to spinal cord stimulator implantation is a very rare occurrence with only two cases reported in the literature so far. We present an illustrative case and discuss the pathophysiology and best clinical management for this very rate entity.

Association between long-term opioid use and cancer risk in patients with chronic pain: a propensity score-matched cohort study

BACKGROUND

Whether long-term opioid use is an independent risk factor for cancer progression remains unclear. Therefore, we conducted a propensity score-matched population-based cohort study to compare cancer incidence between patients with chronic pain with and without opioid use.

METHODS

Data from January 2008 to December 2019 were obtained from the Taiwan National Health Insurance Research Database. Patients were categorised into two groups according to the presence or absence of opioid use, and matched at a 4:1 ratio. The incidence rate ratios for specific cancers were determined.

RESULTS

Propensity score-matching yielded 63 610 patients: 50 888 with opioid use (the opioid group) and 12 722 without (the non-opioid group). In a multivariate Cox regression analysis, the adjusted hazard ratio (95% confidence interval) for cancers in the opioid group compared with the non-opioid group was 2.66 (1.44-2.94; P<0.001). The incidence rate ratios (95% confidence interval) for lung, hepatocellular, colorectal, breast, prostate, head and neck, pancreatic, gastric, oesophageal, and ovarian cancers for the opioid group were 1.87 (1.41-2.43), 1.97 (1.56-2.50), 2.39 (1.87-3.03), 2.43 (1.75-3.33), 2.00 (1.35-3.03), 1.79 (1.14-2.86), 1.87 (1.13-2.12), 2.43 (1.52-3.85), 1.82 (0.92-3.70), and 2.33 (1.01-5.55), respectively.

CONCLUSION

There was an association between long-term opioid use and development of cancer in patients with chronic pain, which should be confirmed in future studies.

Preoperative Opioid Dose and Surgical Outcomes in Colorectal Surgery

BACKGROUND

The worsening opioid epidemic has led to an increased number of surgical patients with chronic preoperative opioid use. However, the impact of opioids on perioperative outcomes has yet to be fully elucidated. The purpose of this study was to assess the association between preoperative opioid dose and surgical outcomes among colectomy patients.

METHODS

Adult colectomy patients in the IBM MarketScan database (2010-2017) were stratified based on preoperative opioid dose, calculated as the average opioid dose in morphine milligram equivalents (MME) in the 90 days prior to surgery: 0 MME, 1 to 49 MME, and 50 or more MME. The association between preoperative opioid dose and anastomotic leak, the primary outcome of interest, as well as other postoperative complications, was assessed using multivariable regression.

RESULTS

Among 45,515 adult colectomy patients, 71.4% did not use opioids (0 MME), 27.4% had an opioid dose between 1 and 49 MME, and 1.2% had an opioid dose at or above 50 MME. Patients with preoperative opioid use exhibited a higher incidence of anastomotic leak (0 MME: 4.8%, 1-49 MME: 5.5%, ≥50 MME: 8.3%; p trend = 0.001). Multivariable analysis demonstrated a dose-response relationship between preoperative opioids and surgical outcomes, as the odds of anastomotic leak worsened with increasing opioid dose (1-49 MME: OR 1.19, 95% CI 1.08-1.31, p < 0.001; ≥50 MME: OR 1.64, 95% CI 1.20-2.24, p = 0.002). Similar dose-response relationships were seen after risk-adjustment for lung complications, pneumonia, delirium, and 30-day readmission (p < 0.05 for all).

CONCLUSIONS

Providers should exercise caution when prescribing opioids preoperatively, as increasing doses of preoperative opioids were associated with worse surgical outcomes and higher 30-day readmission among adult colectomy patients.

Escalated (Dependent) Oxycodone Self-Administration Is Associated with Cognitive Impairment and Transcriptional Evidence of Neurodegeneration in Human Immunodeficiency Virus (HIV) Transgenic Rats

Substance use disorder is associated with accelerated disease progression in people with human immunodeficiency virus (HIV; PWH). Problem opioid use, including high-dose opioid therapy, prescription drug misuse, and opioid abuse, is high and increasing in the PWH population. Oxycodone is a broadly prescribed opioid in both the general population and PWH. Here, we allowed HIV transgenic (Tg) rats and wildtype (WT) littermates to intravenously self-administer oxycodone under short-access (ShA) conditions, which led to moderate, stable, "recreational"-like levels of drug intake, or under long-access (LgA) conditions, which led to escalated (dependent) drug intake. HIV Tg rats with histories of oxycodone self-administration under LgA conditions exhibited significant impairment in memory performance in the novel object recognition (NOR) paradigm. RNA-sequencing expression profiling of the medial prefrontal cortex (mPFC) in HIV Tg rats that self-administered oxycodone under ShA conditions exhibited greater transcriptional evidence of inflammation than WT rats that self-administered oxycodone under the same conditions. HIV Tg rats that self-administered oxycodone under LgA conditions exhibited transcriptional evidence of an increase in neuronal injury and neurodegeneration compared with WT rats under the same conditions. Gene expression analysis indicated that glucocorticoid-dependent adaptations contributed to the gene expression effects of oxycodone self-administration. Overall, the present results indicate that a history of opioid intake promotes neuroinflammation and glucocorticoid dysregulation, and excessive opioid intake is associated with neurotoxicity and cognitive impairment in HIV Tg rats.

Characterization of the Presence and Function of Platelet Opioid Receptors

Opioids are typically used for the treatment of pain related to disease or surgery. In the body, they enter the bloodstream and interact with a variety of immune and neurological cells that express the μ-, δ-, and κ-opioid receptors. One blood-borne cell-like body that is not well understood in the context of opioid interactions is the platelet. The platelet is a highly sensitive anucleate cell-like fragment responsible for maintaining hemostasis through shape change and the secretion of chemical messengers. This research characterizes platelet opioid receptors, how specific receptor agonists impact platelet exocytosis, and the role of the κ-and μ-receptors in platelet function. Platelets were found to express all three opioid receptors, but upon stimulation with their respective agonist no activation was detected. Furthermore, exposure to the opioid agonists did not impact traditional platelet secretion stimulated by thrombin, a natural platelet activator. In addition, data collected from knockout mice suggest that the opioid agonists may be interacting nonspecifically with platelets. Dark-field images revealed differences in activated platelet shape between the κ- and μ-knockout platelets and the control platelets. Finally, κ-knockout platelets showed variations in their ability to adhere and aggregate compared to control platelets. Overall, these data show that platelet function is not likely to be heavily affected by blood-borne opioids.

Morphine promotes migration and lung metastasis of mouse melanoma cells

BACKGROUND

Morphine is an analgesic agent used for cancer pain management. There have been recent concerns that the immunosuppressant properties of morphine can also promote cancer metastasis. Morphine is an agonist for toll like receptor 4 (TLR4) that has a dual role in cancer development. The promotor or inhibitor role of morphine in cancer progression remains controversial. We investigated the effects of morphine on migration and metastasis of melanoma cells through TLR4 activation.

METHODS

Mouse melanoma cells (B16F10) were treated with only morphine (0, 0.1, 1, and 10 μM) or in combination with a TLR4 inhibitor (morphine10 μM +CLI-095 1μM) for either 12 or 24 hours. Migration of cells was analyzed by transwell migration assays. Twenty C57BL/6 male mice were inoculated with B16F10 cells via the left ventricle of the heart and then randomly divided into two groups (n = 10 each) that received either morphine (10 mg.kg^-1, sub-q) or PBS injection for 21 days (control group). Animals were euthanized and their lungs removed for evaluation of metastatic nodules.

RESULTS

Morphine (0.1, 1, and 10 μM) increased cell migration after 12 hours (p < 0.001) and after 24 hours of treatment with morphine (10 μM) (p < 0.001). Treatment with CLI-095 suppressed migration compared to cells treated with morphine alone (p < 0.001). Metastatic nodules in the morphine-treated group (64 nodules) were significantly higher than in the control group (40 nodules) (p < 0.05).

CONCLUSION

Morphine increases the migration and metastasis of mouse melanoma cells by activating TLR4.

Opium Use and Cancer Risk: A Comprehensive Systematic Review and Meta-Analysis of Observational Studies

BACKGROUND

Epidemiological studies have reported inconsistent associations between opium use and cancer risk. We therefore conducted a systematic review and meta-analysis to investigate the relationship between opium use and cancer risk.

METHODS

We searched PubMed, Scopus, ISI Web of Knowledge, and Google Scholar until February 2021 and references of retrieved relevant articles for observational studies that reported the risk of cancer in relation to opium use. Random-effects models were used to calculate pooled effect sizes (ESs) as well as 95% confidence intervals (CIs) for the association between opium use and cancer risk by considering opium doses and types, duration of consumption, and routes of opium use.

RESULTS

In total, 21 observational articles, with a total sample size of 64,412 individuals and 6,658 cases of cancer, were included in this systematic review and meta-analysis. Ever opium users, compared with never opium users, had 3.53 times greater risk of overall cancer (pooled ES: 3.53, 95% CI: 2.60-4.79, P ≤ 0.01). This positive association was also seen for some individual types of cancers except for esophageal and colon cancers. Also, we found that higher opium doses and higher duration of consumption were associated with an increased risk of overall and individual types of cancer. However, the associations between opium doses and the risk of head and neck and larynx cancers were not significant. In terms of the routes of opium use, both opium ingestion and smoking were positively associated with the risk of cancer. Regarding opium types, we found that using teriak, but not shireh, could increase the risk of cancer.

CONCLUSIONS

Our findings showed that opium use, particularly in the form of teriak, is a risk factor for cancer.

Research approaches for evaluating opioid sparing in clinical trials of acute and chronic pain treatments: Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials recommendations

ABSTRACT

Randomized clinical trials have demonstrated the efficacy of opioid analgesics for the treatment of acute and chronic pain conditions, and for some patients, these medications may be the only effective treatment available. Unfortunately, opioid analgesics are also associated with major risks (eg, opioid use disorder) and adverse outcomes (eg, respiratory depression and falls). The risks and adverse outcomes associated with opioid analgesics have prompted efforts to reduce their use in the treatment of both acute and chronic pain. This article presents Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) consensus recommendations for the design of opioid-sparing clinical trials. The recommendations presented in this article are based on the following definition of an opioid-sparing intervention: any intervention that (1) prevents the initiation of treatment with opioid analgesics, (2) decreases the duration of such treatment, (3) reduces the total dosages of opioids that are prescribed for or used by patients, or (4) reduces opioid-related adverse outcomes (without increasing opioid dosages), all without causing an unacceptable increase in pain. These recommendations are based on the results of a background review, presentations and discussions at an IMMPACT consensus meeting, and iterative drafts of this article modified to accommodate input from the co-authors. We discuss opioid sparing definitions, study objectives, outcome measures, the assessment of opioid-related adverse events, incorporation of adequate pain control in trial design, interpretation of research findings, and future research priorities to inform opioid-sparing trial methods. The considerations and recommendations presented in this article are meant to help guide the design, conduct, analysis, and interpretation of future trials.

Quantitative evidence of suppressed TMEM119 microglial immunohistochemistry in fatal morphine intoxications

The aim of this pilot study was to investigate the diagnostic potential of TMEM119 as a useful microglia-specific marker in combination with immunostainings for phagocytic function and infiltrating capacity of monocytes in cases of lethal monosubstance intoxications by morphine (MOR), methamphetamine (METH), and of ethanol-associated death (ETH) respectively. Human brain tissue samples were obtained from forensic autopsies of cases with single substance abuse (MOR, n = 8; ETH, n = 10; METH, n = 9) and then compared to a cohort of cardiovascular fatalities as controls (n = 9). Brain tissue samples of cortex, white matter, and hippocampus were collected and stained immunohistochemically with antibodies against TMEM119, CD68KiM1P, and CCR2. We could document the lowest density of TMEM119-positive cells in MOR deaths with highly significant differences to the control densities in all three regions investigated. In ETH and METH deaths, the expression of TMEM119 was comparable to cell densities in controls. The results indicate that the immunoreaction in brain tissue is different in these groups depending on the drug type used for abuse.

Multiple Sclerosis and the Endogenous Opioid System

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

The Guts of the Opioid Crisis

Bidirectional interactions of the gut epithelium with commensal bacteria are critical for maintaining homeostasis within the gut. Chronic opioid exposure perturbs gut homeostasis through a multitude of neuro-immune-epithelial mechanisms, resulting in the development of analgesic tolerance, a major underpinning of the current opioid crisis. Differences in molecular mechanisms of opioid tolerance between the enteric and central pain pathways pose a significant challenge for managing chronic pain without untoward gastrointestinal effects.

The morphine/heroin vaccine decreased the heroin-induced antinociceptive and reinforcing effects in three inbred strains mouse

Clinical trials have indicated that a vaccine must be immunogenic in genetically diverse human populations and that immunogenicity and protective efficacy in animal models are two key indices required for the approval of a new vaccine. Additionally, the immune response (immunogenicity) and immunoprotection are dependent on the mouse strain. Therefore, the objective of the present study was to determine the immune response (immunogenicity) and the protective efficacy (behavioral response) in three inbred mouse strains immunized with the M₆TT vaccine. Female BALB/c, C57Bl/6, and DBA/2 inbred mice were immunized with the M₆-TT vaccine. A solid-phase antibody-capture ELISA was used to monitor antibody titer responses after each booster dose in vaccinated animals. The study used tail-flick testing to evaluate the antinociceptive effects induced by heroin. Additionally, heroin-induced locomotor activity and place preference were evaluated. The M₆-TT vaccine was able to generate a specific antibody titer in the three inbred mouse strains evaluated. The antibodies reduced the antinociceptive effect of different doses of heroin. In addition, they decreased the heroin-induced locomotor activity and place preference. These findings suggest that the M₆-TT vaccine generates a powerful immunogenic response capable of reducing the antinociceptive and reinforcing effects of heroin in different inbred mouse strains, which supports its possible future use in clinical trials in genetically diverse human populations.

Predictors of Opioid-related Adverse Pulmonary Events among Older Adults with Chronic Obstructive Pulmonary Disease

Rationale: Although opioids are frequently prescribed in chronic obstructive pulmonary disease (COPD), there is poor understanding regarding which individuals will experience pulmonary harm upon exposure.Objectives: We sought to identify patient characteristics and opioid drug properties predictive of opioid-related adverse pulmonary events among older adults with chronic COPD.Methods: A retrospective, population-based, cohort study design was used, analyzing Ontario heath administrative data. Individuals aged 66 years and older, with validated, physician-diagnosed COPD receiving a new opioid drug were included. Adverse pulmonary events (defined as an emergency room visit, hospitalization, or death related to either COPD or pneumonia) occurring within 30 days following new opioid receipt were considered. Multivariable-adjusted, cause-specific hazard modeling was used to identify predictors of adverse pulmonary events.Results: Out of 169,517 older adults with COPD receiving a new opioid, 4,861 (2.9%) experienced an adverse pulmonary event within 30 days. Factors independently predisposing to adverse pulmonary events included older age (≥85 yr old: hazard ratio [HR], 1.37; 95% confidence interval [CI], 1.26-1.49), long-term-care home residence (HR, 1.32; 95% CI, 1.21-1.44), severe COPD exacerbation within the preceding year (HR, 2.96; 95% CI, 2.77-3.17), comorbidities (including non-COPD lung disease [HR, 1.16; 95% CI, 1.09-1.23], congestive heart failure [HR, 1.22; 95% CI, 1.14-1.30], sleep disorder [HR, 1.22; 95% CI, 1.15-1.30], and dementia [HR, 1.14; 95% CI, 1.05-1.24]); other psychoactive medication receipt, including benzodiazepines (HR, 1.27; 95% CI, 1.19-1.35) and serotonergic antidepressants (HR, 1.10; 95% CI, 1.03-1.19), and receipt of an opioid-only agent (HR, 1.35; 95% CI, 1.26-1.46). Factors that independently protected from adverse pulmonary events included female sex (HR, 0.78; 95% CI, 0.73-0.82), surgery within the preceding year (HR, 0.70; 95% CI, 0.64-0.77), and musculoskeletal disease (HR, 0.75; 95% CI, 0.70-0.80). No significant associations were observed between adverse pulmonary events and opioid half-life duration or opioid daily dosage.Conclusions: Patient and opioid drug factors predictive of opioid-related adverse pulmonary events among older adults with COPD were identified, which may assist with safer opioid prescribing.

Epidural analgesia and mortality after colorectal cancer surgery: A retrospective cohort study

Background

Epidural analgesia (EA) has been the standard of care after major abdominal surgery for many years. This study aimed to correlate EA with postoperative complications, short- and long-term mortality in patients with and without EA after open surgery (OS) and minimally invasive surgery (MIS) for colorectal cancer.

Methods

Patient, clinical and outcome data were obtained from the Swedish Colorectal Cancer Registry and the Swedish Perioperative Registry. All adult patients diagnosed with colorectal cancer without metastases who underwent elective curative MIS or OS for colorectal cancer between January 2016 and December 2018 and who had data recorded in both registries, were included in the study. Data were analyzed for OS and MIS procedures separately. A Poisson regression model was used to investigate the association between EA and the outcomes of interest.

Results

Five thousand seven hundred sixty-two patients were included in the study, 2712 in the MIS and 3050 patients in the OS group. After adjusting for patient specific and clinically relevant variables in the regression model, no statistically significant difference in risk for complications; 30-day, 90-day, and up to 3-year mortality following either MIS or OS could be detected between the EA+ and EA-cohorts.

Conclusions

In this large study cohort, EA as part of the comprehensive care provided was not associated with a reduction in postoperative complications risk or improved 30-day, 90-day, or 3-year survival after MIS or OS for colorectal cancer.

•

No reduction in postoperative complications with epidural analgesia.

•

No reduction in short-term mortality with epidural analgesia after colorectal surgery.

•

No reduction in long-term mortality with epidural analgesia in colorectal cancer.

Intra-host evolutionary dynamics of the hepatitis C virus among people who inject drugs

Most individuals chronically infected with hepatitis C virus (HCV) are asymptomatic during the initial stages of infection and therefore the precise timing of infection is often unknown. Retrospective estimation of infection duration would improve existing surveillance data and help guide treatment. While intra-host viral diversity quantifications such as Shannon entropy have previously been utilized for estimating duration of infection, these studies characterize the viral population from only a relatively short segment of the HCV genome. In this study intra-host diversities were examined across the HCV genome in order to identify the region most reflective of time and the degree to which these estimates are influenced by high-risk activities including those associated with HCV acquisition. Shannon diversities were calculated for all regions of HCV from 78 longitudinally sampled individuals with known seroconversion timeframes. While the region of the HCV genome most accurately reflecting time resided within the NS3 gene, the gene region with the highest capacity to differentiate acute from chronic infections was identified within the NS5b region. Multivariate models predicting duration of infection from viral diversity significantly improved upon incorporation of variables associated with recent public, unsupervised drug use. These results could assist the development of strategic population treatment guidelines for high-risk individuals infected with HCV and offer insights into variables associated with a likelihood of transmission.

A "Drug-Dependent" Immune System Can Compromise Protection against Infection: The Relationships between Psychostimulants and HIV

Psychostimulant use is a major comorbidity in people living with HIV, which was initially explained by them adopting risky behaviors that facilitate HIV transmission. However, the effects of drug use on the immune system might also influence this phenomenon. Psychostimulants act on peripheral immune cells even before they reach the central nervous system (CNS) and their effects on immunity are likely to influence HIV infection. Beyond their canonical activities, classic neurotransmitters and neuromodulators are expressed by peripheral immune cells (e.g., dopamine and enkephalins), which display immunomodulatory properties and could be influenced by psychostimulants. Immune receptors, like Toll-like receptors (TLRs) on microglia, are modulated by cocaine and amphetamine exposure. Since peripheral immunocytes also express TLRs, they may be similarly affected by psychostimulants. In this review, we will summarize how psychostimulants are currently thought to influence peripheral immunity, mainly focusing on catecholamines, enkephalins and TLR4, and shed light on how these drugs might affect HIV infection. We will try to shift from the classic CNS perspective and adopt a more holistic view, addressing the potential impact of psychostimulants on the peripheral immune system and how their systemic effects could influence HIV infection.

Sex differences in circulating inflammatory mediators as a function of substance use disorder

BACKGROUND

Substance use disorders (SUD) with comorbid depression and anxiety are linked to poor treatment outcome and relapse. Although some depressed individuals exhibit elevated blood-based inflammation (interleukin-6 [IL-6] and C reactive protein [CRP]), few studies have examined whether the presence of SUD exacerbates inflammation.

METHODS

Treatment-seeking individuals with major depressive disorder (MDD), anxiety disorders, and/or SUD (N = 160; 80 % with MDD) recruited into the Tulsa 1000 study provided blood samples, participated in clinical interviews, and completed a questionnaire battery querying symptoms of current psychopathology and emotional processing. Analyses followed a multistep process. First, groups were created on the presence versus absence of 1+ lifetime SUD diagnoses: SUD+ (37 F, 43 M) and SUD- (60 F, 20 M). Second, a principal component analysis (PCA) of questionnaire data resulted in two factors, one indexing negative emotionality/withdrawal motivation and one measuring positive emotionality/approach motivation. Third, SUD groups, extracted PCA factors, and nuisance covariates (age, body mass index [BMI], nicotine use, psychotropic medication [and hormone/contraception use in females]) were entered as simultaneous predictors of blood-based inflammation (IL-6, IL-8, IL-10, tumor necrosis factor-α, and CRP).

RESULTS

Within females, SUD + exhibited higher IL-8 and IL-10 but lower CRP levels than SUD-. In contrast, SUD was not associated with biomarker levels in males. Across sexes, higher BMI was linked to higher IL-6 and CRP levels, and within the five biomarkers, IL-6 and CRP shared the most variance.

CONCLUSION

These findings point to sex-specific inflammatory profiles as a function of SUD that may provide new targets for intervention.

Chronic morphine administration differentially modulates viral reservoirs in SIVmac251 infected rhesus macaque model

HIV persists in cellular reservoirs despite effective combined antiretroviral therapy (cART) and there is viremia flare up upon therapy interruption. Opioids modulate the immune system and suppress antiviral gene responses, which significantly impact people living with HIV (PLWH). However, the effect of opioids on viral reservoir dynamics remain elusive. Herein, we developed a morphine dependent SIVmac251 infected Rhesus macaque (RM) model to study the impact of opioids on HIV reservoirs. RMs on a morphine (or saline control) regimen were infected with SIVmac251. The cART was initiated in approximately half the animals five weeks post-infection, and morphine/saline administration continued until the end of the study. Among the untreated RM, we did not find any difference in plasma/CSF or in cell-associated DNA/RNA viral load in anatomical tissues. On the other hand, within the cART suppressed macaques, there was a reduction in cell-associated DNA load, intact proviral DNA levels, and in inducible SIV reservoir in lymph nodes (LNs) of morphine administered RMs. In distinction to LNs, in the CNS, the size of latent SIV reservoirs was higher in the CD11b+ microglia/macrophages in morphine dependent RMs. These results suggest that in the proposed model, morphine plays a differential role in SIV reservoirs by reducing the CD4+ T-cell reservoir in lymphoid tissues, while increasing the microglia/reservoir size in CNS tissue. The findings from this pre-clinical model will serve as a tool for screening therapeutic strategies to reduce/eliminate HIV reservoirs in opioid dependent PLWH.IMPORTANCE Identification and clearance of HIV reservoirs is a major challenge in achieving a cure for HIV. This is further complicated by co-morbidities that may alter the size of the reservoirs. There is an overlap between the risk factors for HIV and opioid abuse. Opiates have been recognized as prominent co-morbidities in HIV-infected populations. People infected with HIV also abusing opioids have immune modulatory effects and more severe neurological disease. However, the impact of opioid abuse on HIV reservoirs remains unclear. In this study, we used morphine dependent SIVmac251 infected rhesus macaque (RM) model to study the impact of opioids on HIV reservoirs. Our studies suggested that people with HIV who abuse opioids had higher reservoirs in CNS than the lymphoid system. Extrapolating the macaque findings in humans suggests that such differential modulation of HIV reservoirs among people living with HIV abusing opioids could be considered for future HIV cure research efforts.

Surrogate Humane Endpoints in Small Animal Models of Acute Lung Injury: A Modified Delphi Consensus Study of Researchers and Laboratory Animal Veterinarians

OBJECTIVES

In many jurisdictions, ethical concerns require surrogate humane endpoints to replace death in small animal models of acute lung injury. Heterogenous selection and reporting of surrogate endpoints render interpretation and generalizability of findings between studies difficult. We aimed to establish expert-guided consensus among preclinical scientists and laboratory animal veterinarians on selection and reporting of surrogate endpoints, monitoring of these models, and the use of analgesia.

DESIGN

A three-round consensus process, using modified Delphi methodology, with researchers who use small animal models of acute lung injury and laboratory animal veterinarians who provide care for these animals. Statements on the selection and reporting of surrogate endpoints, monitoring, and analgesia were generated through a systematic search of MEDLINE and Embase. Participants were asked to suggest any additional potential statements for evaluation.

SETTING

A web-based survey of participants representing the two stakeholder groups (researchers, laboratory animal veterinarians). Statements were rated on level of evidence and strength of support by participants. A final face-to-face meeting was then held to discuss results.

SUBJECTS

None.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Forty-two statements were evaluated, and 29 were rated as important, with varying strength of evidence. The majority of evidence was based on rodent models of acute lung injury. Endpoints with strong support and evidence included temperature changes and body weight loss. Behavioral signs and respiratory distress also received support but were associated with lower levels of evidence. Participants strongly agreed that analgesia affects outcomes in these models and that none may be necessary following nonsurgical induction of acute lung injury. Finally, participants strongly supported transparent reporting of surrogate endpoints. A prototype composite score was also developed based on participant feedback.

CONCLUSIONS

We provide a preliminary framework that researchers and animal welfare committees may adapt for their needs. We have identified knowledge gaps that future research should address.

Effect of Preoperative Opioid Use on Adverse Outcomes, Medical Spending, and Persistent Opioid Use Following Elective Total Joint Arthroplasty in the United States: A Large Retrospective Cohort Study of Administrative Claims Data

Objective

Between 17% and 40% of patients undergoing elective arthroplasty are preoperative opioid users. This US study analyzed patients in this population to illustrate the relationship between preoperative opioid use and adverse surgical outcomes.

Design

Retrospective study of administrative medical and pharmaceutical claims data.

Subjects

Adults (aged 18+) who received elective total knee, hip, or shoulder replacement in 2014–2015.

Methods

A patient was a preoperative opioid user if opioid prescription fills occurred in two periods: 1–30 and 31–90 days presurgery. Zero-truncated Poisson (incidence rate ratio [IRR]), logistic (odds ratio [OR]), Cox (hazard ratio [HR]), and quantile regressions modeled the effects of preoperative opioid use and opioid dose, adjusted for demographics, comorbidities, and utilization.

Results

Among 34,792 patients (38% hip, 58% knee, 4% shoulder), 6,043 (17.4%) were preoperative opioid users with a median morphine equivalent daily dose of 32 mg. Preoperative opioid users had increased length of stay (IRR = 1.03, 95% CI = 1.02 to 1.05), nonhome discharge (OR = 1.10, 95% CI = 1.00 to 1.21), and 30-day unplanned readmission (OR = 1.43, 95% CI = 1.17 to 1.74); experienced 35% higher surgical site infection (HR = 1.35, 95% CI = 1.14 to 1.59) and 44% higher surgical revision (HR = 1.44, 95% CI = 1.21 to 1.71); had a median $1,084 (95% CI = $833 to $1334) increase in medical spend during the 365 days after discharge; and had a 64% lower rate of opioid cessation (HR = 0.34, 95% CI = 0.33 to 0.35) compared with patients not filling two or more prescriptions across periods.

Conclusions

Preoperative opioid users had longer length of stay, increased revision rates, higher spend, and persistent opioid use, which worsened with dose. Adverse outcomes after elective joint replacement may be reduced if preoperative opioid risk is managed through increased monitoring or opioid cessation.

Anaesthetic modality and post-surgical oncological outcomes for paediatric tumours: is there a link?

INTRODUCTION

Children with solid organ tumours often present for curative surgery. Even with the best surgical technique, micrometastases can occur. Preclinical studies support the postulation that neuraxial anaesthesia maintains the body's immune and inflammatory milieu against metastasis. However, human retrospective adult studies showed varying results, and no study has been done in children. We aimed to find out if intraoperative epidural, perioperative opioid and volatile dose are associated with relapse-free survival (RFS) in children with solid organ tumours.

METHODS

This is a retrospective cohort study of 126 children from a tertiary paediatric unit who were diagnosed with solid organ tumours (neuroblastoma, hepatoblastoma or sarcoma) over a 16-year period. RFS, stratified by tumour subtypes, was estimated using the Kaplan-Meier method. Adjusted hazard ratios (aHRs) were obtained from multivariable Cox regression models after taking potential covariates into account.

RESULTS

Of 126 children with solid organ tumours (51.6% neuroblastoma, 34.9% sarcoma and 13.5% hepatoblastoma), 53.2% received combined general anaesthesia (GA)/epidural. A total of 21 (31.3%) and 20 (33.9%) patients relapsed during the study period in the combined GA/epidural group and the GA alone group, respectively. Patients with sarcoma receiving combined GA/epidural had a clinically meaningful lower risk of relapse compared to patients receiving GA alone (aHR 0.51, 95% confidence interval 0.14-1.79), although this was not statistically significant.

CONCLUSION

Our study demonstrated some clinically meaningful associations, especially in paediatric sarcoma patients. Overall, however, there was no statistically significant association between epidural use and an improved RFS.

Evaluation of Murine Macrophage Cytokine Production After In Vivo Morphine Treatment

The discovery of opioid receptor expression on immune cells has originated a large research activity on the possible modulation by opioid drugs of immune system responses. In this chapter we describe an easy methodology useful to obtain information about the potential immunomodulatory activity of opioid drugs. An in vivo treatment schedule is used, and macrophages are studied for their ability to release different cytokines.

Effect of Dexmedetomidine on Perioperative Stress Response and Immune Function in Patients With Tumors

Objective:

This study aims to investigate the effect of dexmedetomidine on perioperative stress response and immune function in patients with tumors.

Methods:

Sixty patients who underwent selective radical gastrectomy for cancer were randomly divided into 3 groups: remifentanil group (group R), dexmedetomidine group (group D), and sufentanil group (group S). Remifentanil, dexmedetomidine, and sufentanil were used as general anesthetics. Endotracheal intubation and mechanical ventilation were performed after the spontaneous respiration disappeared. Then, the data were recorded, and blood samples were collected at all time points.

Results:

The heart rate significantly increased (P < 0.05) at T1 in group S, and both heart rate and mean arterial pressure significantly increased (P < 0.05) in group R when compared to group D. The heart rate significantly increased (P < 0.05) at T2 in group S and group R. Furthermore, the heart rate significantly increased (P < 0.05) at T3 and T4 in group S and group R. Intra-group comparison: The heart rate at T1–T4 and mean arterial pressure at T1–T4 significantly increased (P < 0.05) in group S, and the heart rate at T1 and T4, and mean arterial pressure at T2–T4 significantly increased (P < 0.05) in group R when compared to T0. The serum IL-6, IFN-γ, and β-EP significantly increased (P < 0.05) at T0’ in group S and group R when compared to group D. Blood glucose, and serum IL-10, IFN-γ, and β-EP significantly increased (P < 0.05), while IL-18 significantly decreased (P < 0.05) at T1’ in group S and group R.

Conclusion:

Continuous infusion of dexmedetomidine in combination with the inhalation of sevoflurane is superior to sevoflurane + remifentanil or sufentanil in patients undergoing tumor surgery.

One-Year Results of Prospective Research Study Using 10 kHz Spinal Cord Stimulation in Persistent Nonoperated Low Back Pain of Neuropathic Origin: Maiden Back Study

PURPOSE

Spinal cord stimulation (SCS) is a recommended treatment for chronic neuropathic pain. Persistent nonoperative low back pain of neuropathic origin has profound negative impacts on patient's lives. This prospective, open label, research study aimed to explore the use of SCS in patients with associated features of central sensitisation such as allodynia and hyperalgesia.

MATERIALS AND METHODS

Twenty-one patients with back pain and hyperalgesia or allodynia who had not had prior spinal surgery underwent a SCS trial followed by full implantation. SCS comprised administering electrical impulses epidurally at a frequency of 10 kHz and pulse width of 30 μsec. Patients attended follow-up visits after 6 and 12 months of SCS. Repeated measure ANOVAs/Friedman tests explored change after 6 and 12 months of 10 kHz SCS. Independent sample t-tests/Mann-Whitney U tests examined differences in response after 12 months of 10 kHz SCS.

RESULTS

Back and leg pain, quality of life (QoL), pain-related disability, and morphine equivalence significantly improved compared with baseline following 6 and 12 months of 10 kHz SCS. There were no increases in the consumption of opioids, amitriptyline, gabapentin or pregabalin in any patient. After 12 months of treatment, 52% encountered ≥50% improvement in back pain, 44% achieved remission (0-3 cm back pain VAS), 40% reported ODI scores between 0 and 40 and 60% experienced a reduction of at least 10 ODI points. Patients reporting ≥10-point improvement in ODI had significantly longer pain history durations and experienced significantly greater improvements in back pain, leg pain and QoL than those reporting <10-point improvement in ODI.

CONCLUSION

The 10 kHz SCS improved back and leg pain, QoL, pain-related disability and medication consumption in patients with nonoperative back pain of neuropathic origin. With further research incorporating a sham control arm, the efficacy of 10 kHz SCS in this patient cohort will become more established.

Survival features, prognostic factors, and determinants of diagnosis and treatment among Iranian patients with pancreatic cancer, a prospective study

OBJECTIVES

Investigating the survival features, and determinants of treatment and stage at presentation in Iran.

METHODS

461 patients with pancreatic ductal adenocarcinoma (PC) were prospectively enrolled from Shariati hospital, Tehran, Iran, between 2011-2018. All patients underwent endoscopic ultrasonography, computed tomography scanning, and physical examination. Validated questionnaire was completed for the participants and all were actively followed on monthly basis.

RESULTS

Median survival time was 6.5 months, and 1-, and 5-year survival rates were 26.2%, and 1.5%. Patients who were older (p<0.001), illiterate (p = 0.004), unmarried (p = 0.003), rural inhabitant (p = 0.013), opium user (p = 0.039), and had lower body mass index (BMI) (p = 0.002) had lower overall survival. Tumors located in the head of pancreas were more commonly diagnosed at lower stages (p<0.001). Only 10.4% of patients underwent surgery who were more commonly educated (p<0.001), married (p = 0.005), had a tumor located in the head of pancreas (p = 0.016), and were diagnosed at lower stages (p<0.001). After adjustment for potential confounders and risk factors, rural inhabitance (HR: 1.33 (95% CI: 1.01-1.74)), having more symptoms (HR for each increasing symptom: 1.06 (1.02-1.11)), using opium (HR: 1.51 (1.04-2.20)), having a tumor located in the body of pancreas (HR: 1.33 (1.02-1.75)), and having an advanced tumor stage (HR: 2.07 (1.34-3.19)) remained significantly associated with increased risk of mortality. After the adjusting for potential confounders, we did not find significant relationships between smoking, alcohol intake, and BMI with the risk of death among patients with pancreatic cancer.

CONCLUSIONS

Iranian patients with PC have very poor long-term survival. Besides tumor's stage and location, socioeconomic disparities could affect the probabilities of receiving treatment and/or survival in these patients. Opium use is an independent risk factor for mortality among PC patients in Iran.

An international survey on clinicians' perspectives on the diagnosis and management of chronic intestinal pseudo-obstruction and enteric dysmotility

BACKGROUND

Chronic intestinal pseudo-obstruction (CIPO) and enteric dysmotility (ED) are small intestinal motility disorders defined by radiological and manometric criteria. In the absence of consensus guidelines, we surveyed opinions on the diagnosis and management of CIPO and ED among experts from different countries.

METHODS

A survey questionnaire was circulated electronically to members of the European society for Clinical Nutrition and Metabolism, European Society of Neurogastroenterology and Motility, and United European Gastroenterology. Only responses from participants completing all required components were included.

KEY RESULTS

Of 154 participants, 93% agreed that CIPO and ED should be classified separately. Overall, 73% reported an increasing incidence of CIPO and ED, with hypermobile Ehlers-Danlos Syndrome the group with the largest increase in referrals (37%), particularly in the UK (P < .0001). The majority (95%) find diagnosing CIPO and ED difficult. Notably, antroduodenal manometry, a test mandated to diagnose ED, is infrequently used (only 21% respondents use in >50% cases) and full thickness biopsies were reported to seldom influence medical treatment, nutritional management, and prognosis. Respondents reported that very few treatments are useful for most patients, with bacterial overgrowth treatment, prucalopride, and psychological therapies felt to be the most useful. While only 23% of clinicians felt that parenteral nutrition (PN) improves gastrointestinal symptoms in >50% of cases, 68% reported PN dependency at 5 years in the majority of cases.

CONCLUSIONS AND INFERENCES

These data highlight the difficulties with diagnosing and managing CIPO and ED and underscore the urgent need for international, multidisciplinary, clinical practice guidelines.

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.

The impact of the COVID-19 pandemic on patients awaiting spinal cord stimulation surgery in the United Kingdom: a multi-centre patient survey

Introduction

Spinal cord stimulation (SCS) is a recommended treatment for chronic refractory neuropathic pain. During the COVID-19 pandemic, elective procedures have been postponed indefinitely both to provide capacity to deal with the emergency caseload and to avoid exposure of elective patients to COVID-19. This survey aimed to explore the effect of the pandemic on chronic pain in this group and the views of patients towards undergoing SCS treatment when routine services should resume.

Methods

This was a prospective, multi-centre telephone patient survey that analysed data from 330 patients with chronic pain who were on an SCS waiting list. Questions focussed on severity of pain, effect on mental health, medication consumption and reliance on support networks during the COVID-19 pandemic. Views towards undergoing SCS therapy were also ascertained. Counts and percentages were generated, and chi-square tests of independence explored the impact of COVID-19 risk (very high, high, low) on survey responses.

Results

Pain, mental health and patient's ability to self-manage pain deteriorated in around 47%, 50% and 38% of patients, respectively. Some patients reported increases in pain medication consumption (37%) and reliance on support network (41%). Patients showed a willingness to attend for COVID-19 testing (92%), self-isolate prior to SCS (94%) and undergo the procedure as soon as possible (76%).

Conclusion

Our findings suggest that even during the COVID-19 pandemic, there remains a strong clinical need for patients with chronic pain identified as likely SCS responders to be treated quickly. The current prioritisation of new SCS at category 4 (delayed more than 3 months) is challenged judging by this national survey. These patients are awaiting SCS surgery to relieve severe intractable neuropathic pain. A priority at category 3 (delayed up to 3 months) or in some selected cases, at category 2 are the appropriate priority categories.

Impact of Opioid Use in Hematological Malignancies: Clinical, Immunological and Concomitant Aspects

Opioid agents play a unique role in pain and symptom management for cancer patients. Research shows that opiate use, especially when associated with underlying cancer, has significant effects on hematological parameters. These changes may lead to greater risk for immunosuppression, tumor growth and progression of metastatic processes. The aim of this review is to explore the effects of opiates on various metabolic and biological processes, as well as the hematopoietic system, especially in cancer patients. Our findings demonstrate that the tumor-promoting effects of opiates remain contradictory, as both growth-promoting and anti-tumor effects have been observed. However, available data suggest that opiates can facilitate the proliferation and migration of tumor cells, and understanding of this process on cancer treatment is tremendously important.