Prescription opioids are associated with higher mortality in patients diagnosed with sepsis: A retrospective cohort study using electronic health records

Variation in Use of Medications for Opioid Use Disorder in Critically Ill Patients Across the United States

OBJECTIVES

To describe practice patterns surrounding the use of medications to treat opioid use disorder (MOUD) in critically ill patients.

DESIGN

Retrospective, multicenter, observational study using the Premier AI Healthcare Database.

SETTING

The study was conducted in U.S. ICUs.

PATIENTS

Adult (≥ 18 yr old) patients with a history of opioid use disorder (OUD) admitted to an ICU between 2016 and 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 108,189 ICU patients (658 hospitals) with a history of OUD, 20,508 patients (19.0%) received MOUD. Of patients receiving MOUD, 13,745 (67.0%) received methadone, 2,950 (14.4%) received buprenorphine, and 4,227 (20.6%) received buprenorphine/naloxone. MOUD use occurred in 37.9% of patients who received invasive mechanical ventilation. The median day of MOUD initiation was hospital day 2 (interquartile range [IQR] 1-3) and the median duration of MOUD use was 4 days (IQR 2-8). MOUD use per hospital was highly variable (median 16.0%; IQR 10-24; range, 0-70.0%); admitting hospital explained 8.9% of variation in MOUD use. A primary admitting diagnosis of unintentional poisoning (aOR 0.41; 95% CI, 0.38-0.45), presence of an additional substance use disorder (aOR 0.66; 95% CI, 0.64-0.68), and factors indicating greater severity of illness were associated with reduced odds of receiving MOUD in the ICU.

CONCLUSIONS

In a large multicenter, retrospective study, there was large variation in the use of MOUD among ICU patients with a history of OUD. These results inform future studies seeking to optimize the approach to MOUD use during critical illness.

Opioids and the Gastrointestinal Tract: The Role of Peripherally Active µ-Opioid Receptor Antagonists in Modulating Intestinal Permeability

Opioid receptors are found throughout the gastrointestinal tract, including the large intestine. Many patients treated with opioids experience opioid-induced constipation (OIC). Laxatives are not effective in most patients, and in those who do initially respond, the efficacy of laxatives generally diminishes over time. In addition, OIC does not spontaneously resolve for most patients. However, complications of opioids extend far beyond simply slowing gastrointestinal transit. Opioid use can affect intestinal permeability through a variety of mechanisms. Toll-like receptors are a crucial component of innate immunity and are tightly regulated within the gut epithelium. Pathologic µ-opioid receptor (MOR) and toll-like receptor signaling, resulting from chronic opioid exposure, disrupts intestinal permeability leading to potentially harmful bacterial translocation, elevated levels of bacterial toxins, immune activation, and increased cytokine production. Peripherally active MOR antagonists, including methylnaltrexone, are effective at treating OIC. Benefits extend beyond simply blocking the MOR; these agents also act to ameliorate opioid-induced disrupted intestinal permeability. In this review, we briefly describe the physiology of the gastrointestinal epithelial border and discuss the impact of opioids on gastrointestinal function. Finally, we consider the use of peripherally active MOR antagonists to treat disrupted intestinal permeability resulting from opioid use and discuss the potential for improved morbidity and mortality in patients treated with methylnaltrexone for opioid-induced bowel disorders.

Opioids and Immunosuppression: Clinical Evidence, Mechanisms of Action, and Potential Therapies

Background

In addition to the more well-known adverse effects of opioids, such as constipation, mounting evidence supports underlying immunosuppressive effects as well.

Methods

In this study, we provide a narrative review of preclinical and clinical evidence of opioid suppression of the immune system as well as possible considerations for therapies.

Results

In vitro and animal studies have shown clear effects of opioids on inflammatory cytokine expression, immune cell activity, and pathogen susceptibility. Observational data in humans have so far supported preclinical findings, with multiple reports of increased rates of infections in various settings of opioid use. However, the extent to which this risk is due to the impact of opioids on the immune system compared with other risk factors associated with opioid use remains uncertain. Considering the data showing immunosuppression and increased risk of infection with opioid use, measures are needed to mitigate this risk in patients who require ongoing treatment with opioids. In preclinical studies, administration of opioid receptor antagonists blocked the immunomodulatory effects of opioids.

Conclusions

As selective antagonists of peripheral opioid receptors, peripherally acting mu-opioid receptor (MOR) antagonists may be able to protect against immune impairment while still allowing for opioid analgesia. Future research is warranted to further investigate the relationship between opioids and infection risk as well as the potential application of peripherally acting MOR antagonists to counteract these risks.

Morphine aggravates inflammatory, behavioral, and hippocampal structural deficits in septic rats

Although pain and sepsis are comorbidities of intensive care units, reported data on whether pain control by opioid analgesics could alter inflammatory and end-organ damage caused by sepsis remain inconclusive. Here, we tested the hypothesis that morphine, the gold standard narcotic analgesic, modifies behavioral and hippocampal structural defects induced by sepsis in male rats. Sepsis was induced with cecal ligation and puncture (CLP) and behavioral studies were undertaken 24 h later in septic and/or morphine-treated animals. The induction of sepsis or exposure to morphine (7 mg/kg) elicited similar: (i) falls in systolic blood pressure, (ii) alterations in spatial memory and learning tested by the Morris water maze, and (iii) depression of exploratory behavior measured by the new object recognition test. These hemodynamic and cognitive defects were significantly exaggerated in septic rats treated with morphine compared with individual interventions. Similar patterns of amplified inflammatory (IL-1β) and histopathological signs of hippocampal damage were noted in morphine-treated septic rats. Additionally, the presence of intact opioid receptors is mandatory for the induction of behavioral and hemodynamic effects of morphine because no such effects were observed when the receptors were blocked by naloxone. That said, our findings suggest that morphine provokes sepsis manifestations of inflammation and interrelated hemodynamic, behavioral, and hippocampal deficits.

Extracellular vesicles-Mediators of opioid use disorder?

Opioid use disorder (OUD) is a growing health emergency in the United States leading to an epidemic of overdose deaths. OUD is recognized as an addictive brain disorder resulting in psychological, cognitive and behavioural dysfunction. These observed clinical dysfunctions are a result of cellular changes that occur in the brain. Derangements in inflammation, neurogenesis and synaptic plasticity are observed in the brains of OUD patients. The mechanisms of these derangements are unclear; however, extracellular vesicles (EVs), membrane bound particles containing protein, nucleotides and lipids are currently being investigated as agents that invoke these cellular changes. The primary function of EVs is to facilitate intercellular communication by transfer of cargo (protein, nucleotides and lipids) between cells; however, changes in this cargo have been observed in models of OUD suggesting that EVs may be agents promoting the observed cellular derangements. This review summarizes evidence that altered cargo of EVs, specifically protein and miRNA, in models of OUD promote impairments in neurons, astrocytes and microglial cells. These findings support the premise that opioids alter EVs to detrimentally affect neuro-cellular function resulting in the observed addictive, psychological and neurocognitive deficits in OUD patients.

HIV, opioid use, and alterations to the gut microbiome: elucidating independent and synergistic effects

Background

The microbiome is essential to immune development, defense against pathogens, and modulation of inflammation. Microbial dysbiosis has been reported in various diseases including human immunodeficiency virus (HIV) and opioid use disorder (OUD). Notably, people living with HIV (PLWH) have been reported to both have higher rates of OUD and use opioids at higher rates than the general public. Thus, studying gut microbial alterations in people living with HIV and with OUD could elucidate mechanisms pertaining to how these conditions both shape and are shaped by the microbiome. However, to date few studies have investigated how HIV and OUD in combination impact the microbiome.

Aim of review

Here, we review previous studies outlining interactions between HIV, opioid use, and microbial dysbiosis and describe attempts to treat this dysbiosis with fecal microbial transplantation, probiotics, and dietary changes.

Key scientific concepts of review

While the limited number of studies prevent overgeneralizations; accumulating data suggest that HIV and opioid use together induce distinct alterations in the gut microbiome. Among the three existing preclinical studies of HIV and opioid use, two studies reported a decrease in Lachnospiraceae and Ruminococcaceae, and one study reported a decrease in Muribaculaceae in the combined HIV and opioid group relative to HIV-alone, opioid-alone, or control groups. These bacteria are known to modulate immune function, decrease colonic inflammation, and maintain gut epithelial barrier integrity in healthy individuals. Accordingly, modulation of the gut microbiome to restore gut homeostasis may be attempted to improve both conditions. While mixed results exist regarding treating dysbiosis with microbial restoration in PLWH or in those with opioid dependency, larger well-defined studies that can improve microbial engraftment in hosts hold much promise and should still be explored.

Association between Substance Misuse and Outcomes in Critically III Patients with Pneumonia

Rationale: In patients with pneumonia requiring intensive care unit (ICU) admission, alcohol misuse is associated with increased mortality, but the relationship between other commonly misused substances and mortality is unknown. Objectives: We sought to establish whether alcohol misuse, cannabis misuse, opioid misuse, stimulant misuse, or misuse of more than one of these substances was associated with differences in mortality among ICU patients with pneumonia. Methods: This was a retrospective cohort study of hospitals participating in the Premier Healthcare Database between 2010 and 2017. Patients were included if they had a primary or secondary diagnosis of pneumonia and received antibiotics or antivirals within 1 day of admission. Substance misuse related to alcohol, cannabis, stimulants, and opioids, or more than one substance, were identified from the International Classification of Diseases (Ninth and Tenth Editions). The associations between substance misuse and in-hospital mortality were the primary outcomes of interest. Secondary outcomes included the measured associations between substance misuse disorders and mechanical ventilation, as well as vasopressor and continuous paralytic administration. Analyses were conducted with multivariable mixed-effects logistic regression modeling adjusting for age, comorbidities, and hospital characteristics. Results: A total of 167,095 ICU patients met inclusion criteria for pneumonia. Misuse of alcohol was present in 5.0%, cannabis misuse in 0.6%, opioid misuse in 1.5%, stimulant misuse in 0.6%, and misuse of more than one substance in 1.2%. No evidence of substance misuse was found in 91.1% of patients. In unadjusted analyses, alcohol misuse was associated with increased in-hospital mortality (odds ratio [OR], 1.12; 95% confidence interval [CI], 1.06-1.19), whereas opioid misuse was associated with decreased in-hospital mortality (OR, 0.46; 95% CI, 0.39-0.53) compared with no substance misuse. These findings persisted in adjusted analyses. Although cannabis, stimulant, and more than one substance misuse (a majority of which were alcohol in combination with another substance) were associated with lower odds for in-hospital mortality in unadjusted analyses, these relationships were not consistently present after adjustment. Conclusions: In this study of ICU patients hospitalized with severe pneumonia, substance misuse subtypes were associated with different effects on mortality. Although administrative data can provide epidemiologic insight regarding substance misuse and pneumonia outcomes, biases inherent to these data should be considered when interpreting results.

Assessment of Opioid-Induced Immunomodulation in Experimental and Clinical Sepsis

Opioids remain a standard supportive therapy in patients admitted to the ICU with sepsis. However, as preclinical models indicate an association between opioid exposure and immunosuppression, the use of this class of drugs warrants investigation. The objective of this study was to investigate whether opioid exposure causes immunosuppression in patients with sepsis, and to use a murine sepsis model to determine the effects of opioid exposure on secondary infection.

HYPOTHESIS

We hypothesized opioid exposure would be associated with immunosuppression in patients with sepsis and secondary infection in a murine sepsis model.

METHODS AND MODELS

This was a two-phase preclinical and clinical study. The clinical phase included a subgroup of patients with sepsis from an existing randomized controlled trial while the preclinical phase used a murine model of sepsis with C57BL/6 mice. In the clinical phase, a post hoc analysis was performed in subjects receiving fentanyl versus no opioid receipt. In the preclinical phase, a murine cecal slurry-induced sepsis model followed by secondary infection was used. Mice were randomized to fentanyl versus no fentanyl concomitantly.

RESULTS

In clinical sepsis, a significant decrease in interleukin-23 (IL-23) level in patients with fentanyl exposure was observed and lower IL-23 was associated with mortality (p < 0.001). Other measured cytokines showed no significant differences. Concomitant fentanyl exposure during murine sepsis was associated with a significantly higher bacterial burden (p < 0.001) after secondary infection; however, immune cell counts and plasma cytokine levels were largely unaffected by fentanyl.

INTERPRETATION AND CONCLUSIONS

Minimal alterations in cytokines were seen with opioid exposure during clinical sepsis. In a preclinical model, opioid exposure during sepsis was associated with ineffective bacterial clearance upon secondary infection. Further studies are warranted to evaluate the immunomodulatory role of opioids and their implications, especially in the post-sepsis period.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Nanocarriers for effective delivery: modulation of innate immunity for the management of infections and the associated complications

Innate immunity is the first line of defense against invading pathogens. Innate immune cells can recognize invading pathogens through recognizing pathogen-associated molecular patterns (PAMPs) via pattern recognition receptors (PRRs). The recognition of PAMPs by PRRs triggers immune defense mechanisms and the secretion of pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6. However, sustained and overwhelming activation of immune system may disrupt immune homeostasis and contribute to inflammatory disorders. Immunomodulators targeting PRRs may be beneficial to treat infectious diseases and their associated complications. However, therapeutic performances of immunomodulators can be negatively affected by (1) high immune-mediated toxicity, (2) poor solubility and (3) bioactivity loss after long circulation. Recently, nanocarriers have emerged as a very promising tool to overcome these obstacles owning to their unique properties such as sustained circulation, desired bio-distribution, and preferred pharmacokinetic and pharmacodynamic profiles. In this review, we aim to provide an up-to-date overview on the strategies and applications of nanocarrier-assisted innate immune modulation for the management of infections and their associated complications. We first summarize examples of important innate immune modulators. The types of nanomaterials available for drug delivery, as well as their applications for the delivery of immunomodulatory drugs and vaccine adjuvants are also discussed.

Identifying the Risk of Sepsis in Patients With Cancer Using Digital Health Care Records: Machine Learning-Based Approach

BACKGROUND

Sepsis is diagnosed in millions of people every year, resulting in a high mortality rate. Although patients with sepsis present multimorbid conditions, including cancer, sepsis predictions have mainly focused on patients with severe injuries.

OBJECTIVE

In this paper, we present a machine learning-based approach to identify the risk of sepsis in patients with cancer using electronic health records (EHRs).

METHODS

We utilized deidentified anonymized EHRs of 8580 patients with cancer from the Samsung Medical Center in Korea in a longitudinal manner between 2014 and 2019. To build a prediction model based on physical status that would differ between sepsis and nonsepsis patients, we analyzed 2462 laboratory test results and 2266 medication prescriptions using graph network and statistical analyses. The medication relationships and lab test results from each analysis were used as additional learning features to train our predictive model.

RESULTS

Patients with sepsis showed differential medication trajectories and physical status. For example, in the network-based analysis, narcotic analgesics were prescribed more often in the sepsis group, along with other drugs. Likewise, 35 types of lab tests, including albumin, globulin, and prothrombin time, showed significantly different distributions between sepsis and nonsepsis patients (P<.001). Our model outperformed the model trained using only common EHRs, showing an improved accuracy, area under the receiver operating characteristic (AUROC), and F1 score by 11.9%, 11.3%, and 13.6%, respectively. For the random forest-based model, the accuracy, AUROC, and F1 score were 0.692, 0.753, and 0.602, respectively.

CONCLUSIONS

We showed that lab tests and medication relationships can be used as efficient features for predicting sepsis in patients with cancer. Consequently, identifying the risk of sepsis in patients with cancer using EHRs and machine learning is feasible.

Opioid Use, Gut Dysbiosis, Inflammation, and the Nervous System

Opioid use disorder (OUD) is defined as the chronic use or misuse of prescribed or illicitly obtained opioids and is characterized by clinically significant impairment. The etiology of OUD is multifactorial as it is influenced by genetics, environmental factors, stress response and behavior. Given the profound role of the gut microbiome in health and disease states, in recent years there has been a growing interest to explore interactions between the gut microbiome and the central nervous system as a causal link and potential therapeutic source for OUD. This review describes the role of the gut microbiome and opioid-induced immunopathological disturbances at the gut epithelial surface, which collectively contribute to OUD and perpetuate the vicious cycle of addiction and relapse.

Immunomodulatory effects of pharmaceutical opioids and antipyretic analgesics: Mechanisms and relevance to infection

Understanding how pharmaceutical opioids and antipyretic analgesics interact with the immune system potentially has major clinical implications for management of patients with infectious diseases and surgical and critical care patients. An electronic search was carried out on MEDLINE, EMBASE, PsycINFO, CENTRAL and the Cochrane library to identify reports describing the immunomodulatory effects of opioid analgesics and antipyretic analgesics, and their effects in infectious diseases. In adaptive immunity, nonsteroidal anti-inflammatory drugs have divergent effects: augmenting cell-mediated immunity but inhibiting humoral immunity. Nonsteroidal anti-inflammatory drugs have demonstrated a beneficial role in Mycobacterium tuberculosis infection and histoplasmosis in animals, and may be plausible adjuvants to antimicrobial agents in these diseases. There is a need to evaluate these findings rigorously in human clinical trials. There is preliminary evidence demonstrating antiviral effects of indomethacin in SARS CoV-2 in vitro; however, uncertainty regarding its clinical benefit in humans needs to be resolved in large clinical trials. Certain opioid analgesics are associated with immunosuppressive effects, with a developing understanding that fentanyl, morphine, methadone and buprenorphine suppress innate immunity, whilst having diverse effects on adaptive immunity. Morphine suppresses key cells of the innate immunity and is associated with greater risk of infection in the postsurgical setting. Efforts are needed to achieve adequate analgesia whilst avoiding suppression of the innate immunity in the immediate postoperative period caused by certain opioids, particularly in cancer surgery.

Opioids and Sepsis: Elucidating the Role of the Microbiome and microRNA-146

Sepsis has recently been defined as life-threatening organ dysfunction caused by the dysregulated host response to an ongoing or suspected infection. To date, sepsis continues to be a leading cause of morbidity and mortality amongst hospitalized patients. Many risk factors contribute to development of sepsis, including pain-relieving drugs like opioids, which are frequently prescribed post-operatively. In light of the opioid crisis, understanding the interactions between opioid use and the development of sepsis has become extremely relevant, as opioid use is associated with increased risk of infection. Given that the intestinal tract is a major site of origin of sepsis-causing microbes, there has been an increasing focus on how alterations in the gut microbiome may predispose towards sepsis and mediate immune dysregulation. MicroRNAs, in particular, have emerged as key modulators of the inflammatory response during sepsis by tempering the immune response, thereby mediating the interaction between host and microbiome. In this review, we elucidate contributing roles of microRNA 146 in modulating sepsis pathogenesis and end with a discussion of therapeutic targeting of the gut microbiome in controlling immune dysregulation in sepsis.

Epidemiology, Outcomes, and Trends of Patients With Sepsis and Opioid-Related Hospitalizations in U.S. Hospitals

OBJECTIVES

Widespread use and misuse of prescription and illicit opioids have exposed millions to health risks including serious infectious complications. Little is known, however, about the association between opioid use and sepsis.

DESIGN

Retrospective cohort study.

SETTING

About 373 U.S. hospitals.

PATIENTS

Adults hospitalized between January 2009 and September 2015.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Sepsis was identified by clinical indicators of concurrent infection and organ dysfunction. Opioid-related hospitalizations were identified by the International Classification of Diseases, 9th Revision, Clinical Modification codes and/or inpatient orders for buprenorphine. Clinical characteristics and outcomes were compared by sepsis and opioid-related hospitalization status. The association between opioid-related hospitalization and all-cause, in-hospital mortality in patients with sepsis was assessed using mixed-effects logistic models to adjust for baseline characteristics and severity of illness.The cohort included 6,715,286 hospitalizations; 375,479 (5.6%) had sepsis, 130,399 (1.9%) had opioid-related hospitalizations, and 8,764 (0.1%) had both. Compared with sepsis patients without opioid-related hospitalizations (n = 366,715), sepsis patients with opioid-related hospitalizations (n = 8,764) were younger (mean 52.3 vs 66.9 yr) and healthier (mean Elixhauser score 5.4 vs 10.5), had more bloodstream infections from Gram-positive and fungal pathogens (68.9% vs 47.0% and 10.6% vs 6.4%, respectively), and had lower in-hospital mortality rates (10.6% vs 16.2%; adjusted odds ratio, 0.73; 95% CI, 0.60-0.79; p < 0.001 for all comparisons). Of 1,803 patients with opioid-related hospitalizations who died in-hospital, 928 (51.5%) had sepsis. Opioid-related hospitalizations accounted for 1.5% of all sepsis-associated deaths, including 5.7% of sepsis deaths among patients less than 50 years old. From 2009 to 2015, the proportion of sepsis hospitalizations that were opioid-related increased by 77% (95% CI, 40.7-123.5%).

CONCLUSIONS

Sepsis is an important cause of morbidity and mortality in patients with opioid-related hospitalizations, and opioid-related hospitalizations contribute disproportionately to sepsis-associated deaths among younger patients. In addition to ongoing efforts to combat the opioid crisis, public health agencies should focus on raising awareness about sepsis among patients who use opioids and their providers.

Opioid Modulation of the Gut-Brain Axis in Opioid-Associated Comorbidities

Growing evidence from animal and human studies show that opioids have a major impact on the composition and function of gut microbiota. This leads to disruption in gut permeability and altered microbial metabolites, driving both systemic and neuroinflammation, which in turn impacts central nervous system (CNS) homeostasis. Tolerance and dependence are the major comorbidities associated with prolonged opioid use. Inflammatory mediators and signaling pathways have been implicated in both opioid tolerance and dependence. We provide evidence that targeting the gut microbiome during opioid use through prebiotics, probiotics, antibiotics, and fecal microbial transplantation holds the greatest promise for novel treatments for opioid abuse. Basic research and clinical trials are required to examine what is more efficacious to yield new insights into the role of the gut-brain axis in opioid abuse.

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.

Where to Next? Research Directions after the First Hepatitis C Vaccine Efficacy Trial

Thirty years after its discovery, the hepatitis C virus (HCV) remains a leading cause of liver disease worldwide. Given that many countries continue to experience high rates of transmission despite the availability of potent antiviral therapies, an effective vaccine is seen as critical for the elimination of HCV. The recent failure of the first vaccine efficacy trial for the prevention of chronic HCV confirmed suspicions that this virus will be a challenging vaccine target. Here, we examine the published data from this first efficacy trial along with the earlier clinical and pre-clinical studies of the vaccine candidate and then discuss three key research directions expected to be important in ongoing and future HCV vaccine development. These include the following: 1. design of novel immunogens that generate immune responses to genetically diverse HCV genotypes and subtypes, 2. strategies to elicit broadly neutralizing antibodies against envelope glycoproteins in addition to cytotoxic and helper T cell responses, and 3. consideration of the unique immunological status of individuals most at risk for HCV infection, including those who inject drugs, in vaccine platform development and early immunogenicity trials.

The immunomodulatory effects of opioids and implications for intensive care unit populations

Analgesia within the intensive care unit (ICU) is often achieved via the utilization of opioids in alignment with current guidelines. Recent evidence has not only demonstrated the potential impact of opioids in suppression of immune function, but also the potential harm of immunosuppression of patients within the ICU. Despite the potential immunosuppression seen with opioids in this at-risk population, their use remains frequent. In this review, we highlight the potential immunomodulatory impact of opioids within the critically ill and considerations for their use.

Immune modulation mediated by extracellular vesicles of intestinal organoids is disrupted by opioids

Extracellular vesicles (EVs) are effective mediators of intercellular communications between enterocytes and immune cells. The current study showed that EVs isolated from mouse and human intestinal organoids modulated inflammatory responses of various immune cells including mouse bone-marrow derived-macrophages, dendritic cells, microglia cells, and human monocytes. EVs suppressed LPS-elicited cytokine production in these cells while morphine abolished EVs' immune modulatory effects. Microarray analysis showed that various microRNAs, especially Let-7, contributed to EV-mediated immune modulation. Using murine models, we showed that injection of EVs derived from intestinal organoids reduced endotoxin-induced systemic inflammation and alleviated the symptoms of DSS-induced colitis. EVs derived from morphine-treated organoids failed to suppress the immune response in both these models. Our study suggests that EVs derived from intestinal crypt cells play crucial roles in maintaining host homeostasis and opioid use is a risk factor for exacerbating inflammation in patients with inflammatory diseases such as sepsis and colitis.

Postoperative around-the-clock administration of intravenous acetaminophen for pain control following robot-assisted radical prostatectomy

The objective of this study was to examine the impact of around-the-clock (ATC) administration of intravenous (IV) acetaminophen following robot-assisted radical prostatectomy (RARP). Intravenous infusion of acetaminophen was started on the day of the operation at 1000 mg/dose every 6 h, and the infusion was continued on a fixed schedule until postoperative day 2 a.m. In a retrospective observational study, we compared 127 patients who were administered IV acetaminophen on a fixed schedule (ATC group) with 485 patients who were administered analgesic drugs only as needed (PRN group). We investigated postoperative pain intensity and additional analgesic consumption on postoperative day 0, 1, 2, 3, and 5 between the two groups. Postoperative pain scores were significantly lower in the ATC group than in the PRN group at 1 and 2 days, and this period matched the duration of ATC administration of IV acetaminophen. Postoperative frequency of rescue analgesia was significantly lower in the ATC group than in the PRN group at postoperative 0, 1, and 2 days. ATC administration of IV acetaminophen has the potential to be a very versatile and valuable additional dose to achieve appropriate postoperative analgesia in patients with RARP.

Evaluation of Infectious Disease Test Ordering and Positivity Rates in Illicit Fentanyl Users

BACKGROUND

The emergence of illicit fentanyl use has resulted in considerable morbidity and mortality. Although illicit use of other opioids has been associated with transmission of viral and bacterial infections, limited data exist for the prevalence of infectious diseases among illicit fentanyl users. The purpose of this study was to assess the likelihood of infectious disease testing and infection prevalence among illicit fentanyl users.

METHODS

Results from urine drug screens (UDSs) performed from August 13, 2019, to October 16, 2019, were obtained from the laboratory information system with concurrent microbial testing. Patients were categorized based on UDS results, and illicit drug use was inferred from physician encounter notes in the electronic medical record.

RESULTS

Suspected illicit drugs users with fentanyl detected by UDS were more likely to be screened [odds ratio (OR): 1.7; 95% CI, 1.26-2.4] and test positive for hepatitis C virus (HCV) by immunoassay (OR: 5.89; 95% CI, 2.93-11.31) than patients without drugs detected. Patients with suspected illicit fentanyl use who were discharged from the emergency department (ED) were less likely to be tested for HCV than patients in outpatient settings (OR: 3.47; 95% CI, 1.05-10.4) and inpatient settings (OR: 17.43; 95% CI, 6.53-45.88). Patients with suspected illicit fentanyl use were more likely to have infected abscesses or wounds (OR: 5.12; 95% CI, 2.07-13.7) and Staphylococcus aureus infections (OR: 4.5; 95% CI, 1.59-12.28) than patients without drugs detected.

CONCLUSIONS

Patients with a positive UDS for fentanyl and suspected illicit use were more likely to test positive for HCV, were rarely screened for HCV in the ED, and had an increased risk of invasive S. aureus wound or abscess infection. These findings may represent considerable barriers to care for patients who use fentanyl illicitly.

Opioid Use Disorder and Associated Infectious Disease: The Role of the Laboratory in Addressing Health Disparities

BACKGROUND

Opioid use disorder, defined as a pattern of problematic opioid use leading to clinically significant impairment, has resulted in considerable morbidity and mortality throughout the world. This is due, at least in part, to the marginalized status of patients with opioid use disorder, limiting their access to appropriate laboratory testing, diagnosis, and treatment. Infections have long been associated with illicit drug use and contribute considerably to morbidity and mortality. However, barriers to testing and negative stigmas associated with opioid use disorder present unique challenges to infectious disease testing in this patient population.

CONTENT

This review addresses the associations between opioid use disorder and infectious organisms, highlighting the health disparities encountered by patients with opioid use disorder, and the important role of laboratory testing for diagnosing and managing these patients.

SUMMARY

Infections are among the most frequent and adverse complications among patients with opioid use disorder. As a result of health disparities and systemic biases, patients that misuse opioids are less likely to receive laboratory testing and treatment. However, laboratories play a crucial in identifying patients that use drugs illicitly and infections associated with illicit drug use.

Pain, Motivation, Migraine, and the Microbiome: New Frontiers for Opioid Systems and Disease

For decades the broad role of opioids in addiction, neuropsychiatric disorders, and pain states has been somewhat well established. However, in recent years, with the rise of technological advances, not only is the existing dogma being challenged, but we are identifying new disease areas in which opioids play a critical role. This review highlights four new areas of exploration in the opioid field. The most recent addition to the opioid family, the nociceptin receptor system, shows promise as the missing link in understanding the neurocircuitry of motivation. It is well known that activation of the kappa opioid receptor system modulates negative affect and dysphoria, but recent studies now implicate the kappa opioid system in the modulation of negative affect associated with pain. Opioids are critical in pain management; however, the often-forgotten delta opioid receptor system has been identified as a novel therapeutic target for headache disorders and migraine. Lastly, changes to the gut microbiome have been shown to directly contribute to many of the symptoms of chronic opioid use and opioid related behaviors. This review summarizes the findings from each of these areas with an emphasis on identifying new therapeutic targets. SIGNIFICANCE STATEMENT: The focus of this minireview is to highlight new disease areas or new aspects of disease in which opioids have been implicated; this includes pain, motivation, migraine, and the microbiome. In some cases, this has resulted in the pursuit of a novel therapeutic target and resultant clinical trial. We believe this is very timely and will be a refreshing take on reading about opioids and disease.

Prescription Opioids induce Gut Dysbiosis and Exacerbate Colitis in a Murine Model of Inflammatory Bowel Disease

BACKGROUND AND AIMS

Opioids are the most prescribed analgesics for pain in inflammatory bowel diseases [IBD]; however, the consequences of opioid use on IBD severity are not well defined. This is the first study investigating consequences of hydromorphone in both dextran sodium sulphate [DSS]-induced colitis and spontaneous colitis (IL-10 knockout [IL-10-/-]) mouse models of IBD.

METHODS

To determine the consequences of opioids on IBD pathogenesis, wild-type [WT] mice were treated with clinically relevant doses of hydromorphone and colitis was induced via 3% DSS in drinking water for 5 days. In parallel we also determined the consequences of opioids in a spontaneous colitis model.

RESULTS

Hydromorphone and DSS independently induced barrier dysfunction, bacterial translocation, disruption of tight junction organisation and increased intestinal and systemic inflammation, which were exacerbated in mice receiving hydromorphone in combination with DSS. Hydromorphone + DSS-treated mice exhibited significant microbial dysbiosis. Predictive metagenomic analysis of the gut microbiota revealed high abundance in the bacterial communities associated with virulence, antibiotic resistance, toxin production, and inflammatory properties. Hydromorphone modulates tight junction organisation in a myosin light chain kinase [MLCK]-dependent manner. Treatment with MLCK inhibitor ML-7 ameliorates the detrimental effects of hydromorphone on DSS-induced colitis and thus decreases severity of IBD. Similarly, we demonstrated that hydromorphone treatment in IL-10-/- mice resulted in accelerated clinical manifestations of colitis compared with control mice.

CONCLUSIONS

Opioids used for pain management in IBD accelerate IBD progression by dysregulation of the gut microbiota, leading to expansion of pathogenic bacteria, translocation of bacteria, immune deregulation and sustained inflammation.

Opioids and Cancer Mortality

OPINION STATEMENT

Opioids are the gold standard for the treatment of cancer-related pain. Preclinical studies have associated opioids with cancer progression and overall survival. In mice models, opioids have been shown to possess pro-tumor activity secondary to immunosuppression, migration of tumor cells, increased activity of vascular endothelial growth factor receptors, and angiogenesis leading to tumor progression. In contrast, opioids have also been associated with having antitumor activity by activation of apoptosis and phagocytosis. However, high-quality randomized controlled trials in humans that are focused on the association between opioids and survival in cancer patients are lacking, which underscores the importance of being cautious when interpreting the results of the preclinical studies. Cancer-related pain is complex and multifactorial and may worsen as the disease progresses leading to higher opioid utilization. Moreover, cancer pain by itself has been associated with poor survival. The survival in these advanced cancer patients taking opioids may be more likely to be associated with cancer progression and not the opioid use. Adequate treatment of cancer pain has the potential to improve quality of life and performance status, highlighting the importance of continuing to use opioids to manage pain efficiently. More research is clearly needed.

Opioids Impair Intestinal Epithelial Repair in HIV-Infected Humanized Mice

Intestinal barrier dysfunction and subsequent microbial translocation play crucial roles in persistent immune activation leading to HIV disease progression. Opioid use is associated with worse outcome in HIV-infected patients. The exacerbated disease progression by opioids is mainly driven by excessive intestinal inflammation and increased gut permeability. The objective of this study is to investigate how opioids potentiate HIV disease progression by compromising intestinal barrier function and impairing intestinal epithelial self-repair mechanism. In the present study, abnormal intestinal morphology and reduced epithelial proliferation were observed in bone marrow-liver-thymus humanized mice and in HIV-infected patients who were exposed to opioids. In bone marrow-liver-thymus mice, HIV, and morphine independently, and additively induced gut dysbiosis, especially depletion of Lachnospiraceae, Ruminococcaceae, and Muribaculaceae. We also observed that the abundance of Lachnospiraceae, Ruminococcaceae, and Muribaculaceae negatively correlated with apoptosis of epithelial cells, and intestinal IL-6 levels. Previous studies have shown that these bacterial families play crucial roles in maintaining intestinal homeostasis because they include most short-chain fatty acid-producing members. Short-chain fatty acids have been shown to maintain stem cell populations and suppress inflammation in the gut by inhibiting histone deacetylases (HDAC). In addition, we demonstrate that morphine exposure inhibited growth of intestinal organoids derived from HIV transgenic mice by suppressing Notch signaling in an HDAC-dependent manner. These studies implicate an important role for HDAC in intestinal homeostasis and supports HDAC modulation as a therapeutic intervention in improving care of HIV patients, especially in opioid-abusing population.

The Influence of Pain and Analgesia in Rodent Models of Sepsis

Sepsis is a multifaceted host response to infection that dramatically affects patient outcomes and the cost of health care. Animal models are necessary to replicate the complexity and heterogeneity of clinical sepsis. However, these models entail a high risk of pain and distress due to tissue trauma, inflammation, endotoxin-mediated hyperalgesia, and other mechanisms. Several recent studies and initiatives address the need to improve the welfare of animals through analgesics and standardize the models used in preclinical sepsis research. Ultimately, the goal is to provide high-fidelity, humane animal models that better replicate the clinical course of sepsis, to provide more effective translation and advance therapeutic discovery. The purpose of this review is to discuss the current understanding of the roles of pain and analgesia in rodent models of sepsis. The current definitions of sepsis along with an overview of pain in human sepsis are described. Finally, welfare concerns associated with animal models of sepsis and the most recent considerations for relief of pain and distress are reviewed.

Buprenorphine Markedly Elevates a Panel of Surrogate Markers in a Murine Model of Sepsis

Sepsis can be simulated in animals by perforating the cecum via a surgical procedure termed "cecal ligation and puncture" (CLP), which induces similar inflammatory responses as observed during the clinical course of human sepsis. In addition to anesthetic agents, many Institutional Animal Care and Use Committees often recommend the use of additional analgesic agents (such as opioid) to further augment the initial anesthetic effects. However, emerging evidence suggest that a commonly recommended opioid, buprenorphine, dramatically elevated circulating interleukin (IL)-6 levels, and reduced animal survival in male C57BL/6 mice, but not in female mice possibly due to the complex interference of estrous cycles, fueling an ongoing debate regarding the possible impact of analgesic administration on the sepsis-induced systemic inflammation. As per the recommendation of a local government agency, we performed a pilot study and confirmed that repetitive administration of buprenorphine indeed markedly elevated circulating levels of four sepsis surrogate markers (e.g., IL-6, KC, monocyte chemoattractant protein-1, and granulocyte-colony stimulating factor) in 20% to 60% of septic animals. This complication may adversely jeopardize our ability to use the CLP model to reliably simulate human sepsis, and to understand the complex mechanism underlying the pathogenesis of lethal sepsis. Thus, for experimental sepsis studies set to survey systemic inflammation and animal lethality at relatively later stages (e.g., at 24 h post CLP and beyond), we strongly recommend not to repetitively administer buprenorphine to eliminate its potential complication to animal sepsis models.

Opioid use potentiates the virulence of hospital-acquired infection, increases systemic bacterial dissemination and exacerbates gut dysbiosis in a murine model of Citrobacter rodentium infection

Opioid analgesics are frequently prescribed in the United States and worldwide. However, serious side effects such as addiction, immunosuppression and gastrointestinal symptoms limit their use. It was recently demonstrated that morphine treatment results in a significant disruption in gut barrier function, leading to an increased translocation of gut commensal bacteria. Further studies have indicated distinct alterations in the gut microbiome and metabolome following morphine treatment, contributing to the negative consequences that are associated with opioid use. However, it is unclear how opioids modulate gut homeostasis in the context of a hospital-acquired bacterial infection. Citrobacter rodentium is an ideal murine model of human infections with enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC). In the current study, a mouse model of C. rodentium infection was used to investigate the role of morphine in the modulation of gut homeostasis in the context of a hospital-acquired bacterial infection. Morphine treatment resulted in 1) the promotion of C. rodentium systemic dissemination, 2) an increase in the expression of the virulence factors of C. rodentium colonization in intestinal contents, 3) altered gut microbiome, 4) damaged integrity of gut epithelial barrier function, 5) inhibition of the C. rodentium-induced increase in goblet cells, and 6) dysregulated IL-17A immune response. This study demonstrates and further validates a positive correlation between opioid drug use/abuse and an increased risk of infections, suggesting that the overprescription of opioids may increase the susceptibility to hospital-acquired infection.

Opioid Use and Outcomes in Hospitalized Older Patients With Heart Failure Receiving and Not Receiving Hospice Referrals

BACKGROUND

The use of opioids is associated with poor outcomes. Less is known about this association in patients with heart failure (HF) and whether it varies by the receipt of hospice care.

METHODS

Of the 7467 patients hospitalized for HF without previous opioid use, 124 received discharge opioids. We matched 123 of these patients with 123 not receiving opioids based on their propensity scores for opioid use, thus assembling a matched cohort of 246 patients balanced on 30 baseline characteristics (mean age, 76 years, 60% women, and 11% African American). We repeated the process in hospice (n = 155; 20 received opioids) and nonhospice (n = 7298; 104 received opioids) subgroups, thus assembling 2 matched cohorts of 22 and 208 patients, respectively. Hazard ratios (HRs) and 95% confidence intervals (CIs) associated with opioid use were estimated from matched cohorts.

RESULTS

During 8.6 (median, 1.4) years of follow-up, all-cause mortality occurred in 80% and 68% of matched patients in the opioid and nonopioid groups, respectively (HR, 1.49; 95% CI, 1.11-1.99; P = 0.008). There was evidence of heterogeneity in this association between hospice and nonhospice patients (P for interaction, 0.027). Among matched hospice and nonhospice patients, HRs (95% CIs) for mortality were 6.37 (2.06-19.69; P = 0.001) and 1.42 (1.03-1.96; P = 0.035), respectively. HRs (95% CIs) for 30-day and 1-year mortality were 1.98 (1.06-3.70; P = 0.033) and 1.72 (1.18-2.49; P = 0.004), respectively. HRs (95% CIs) for all-cause, HF, and non-HF readmissions were 1.31 (0.97-1.76; P = 0.079), 1.03 (0.71-1.49; P = 0.866), and 1.75 (1.05-2.91; P = 0.031), respectively. Readmission associations were similar among matched nonhospice patients. There was no readmission among matched hospice patients receiving opioids.

CONCLUSIONS

In older patients with HF, opioid use is associated with a higher risk of mortality, which is greater in the hospice subgroup, and a higher risk of non-HF readmission in the nonhospice subgroup.

A potential role for the gut microbiome in substance use disorders

Pathological substance use disorders represent a major public health crisis with limited effective treatment options. While much work has been done to understand the neuronal signaling networks and intracellular signaling cascades associated with prolonged drug use, these studies have yielded few successful treatment options for substance use disorders. In recent years, there has been a growing interest to explore interactions between the peripheral immune system, the gut microbiome, and the CNS. In this review, we will present a summary of existing evidence, suggesting a potential role for gut dysbiosis in the pathogenesis of substance use disorders. Clinical evidence of gut dysbiosis in human subjects with substance use disorder and preclinical evidence of gut dysbiosis in animal models of drug addiction are discussed in detail. Additionally, we examine how changes in the gut microbiome and its metabolites may not only be a consequence of substance use disorders but may in fact play a role in mediating behavioral response to drugs of abuse. While much work still needs to be done, understanding the interplay of gut microbiome in substance use disorders may offer a promising avenue for future therapeutic development.