Opioids and opiates: analgesia with cardiovascular, haemodynamic and immune implications in critical illness

The risks of sedation and pain control during burn resuscitation: Increased opioids lead to over-resuscitation and hypotension

INTRODUCTION

Pain management and sedation are necessary in severely burned persons. Balancing pain control, obtundation, and hemodynamic suppression can be challenging. We hypothesized that increased sedation during burn resuscitation is associated with increased intravenous fluid administration and hemodynamic instability.

METHODS

A retrospective review of a single burn center was performed from 2014 to 2019 for all admissions to the burn unit with > 20% total body surface area (TBSA) burns. Within 48 h of admission, we compared total amounts of sedation/pain medications (morphine milligram equivalents (MME), propofol, dexmedetomidine, benzodiazepines) with total resuscitation volumes and frequency of hypotensive episodes. Resuscitation volumes and frequency of hypotension were modeled with multivariable linear regression adjusting for burn severity and weight.

RESULTS

208 patients were included with median age of 43 years (IQR 29-55) and median %TBSA of 31 (IQR 25-44). Median 48-hour resuscitation milliliters per weight per %TBSA were 3.3 (IQR 2.28-4.92). Pain/sedative medications included a combination of opioids in 99%, benzodiazepines in 73%, propofol in 31%, and dexmedetomidine in 11% of patients. MMEs were associated with greater resuscitation volumes (95% CI: 0.15-0.54, p = 0.01) as well as number of hypotensive events (95% CI: 1.57-2.7, p < 0.001). No associations were noted with other sedative medications when comparing the number of hypotensive events and resuscitation volumes.

CONCLUSIONS

Increased opioid administration has physiological consequences and should be carefully monitored during resuscitation as higher volume administrations lead to worse outcomes. Opioids and sedating medications should be titrated to the least amount needed to achieve reasonable comfort and sedation.

Signal of harm in morphine use in adults with acute pulmonary oedema: A rapid systematic review

BACKGROUND

Heart failure affects nearly 65 million people globally, resulting in recurrent hospital admissions and substantial healthcare expenditure. The use of morphine in the management of acute pulmonary oedema remains controversial, with conflicting guidance and significant variation in practice. Synthesised evidence is needed to inform standard treatment guidelines and clinical practice.

OBJECTIVE

To determine whether morphine should be used in the treatment of acute pulmonary oedema (APE) in adults.

METHODS

A rapid review of systematic reviews of randomised controlled trials or observational studies, and then randomised controlled trials, was conducted searching three electronic databases (PubMed, Embase, Cochrane Library) and one clinical trial registry on 12 February 2022. We used a prespecified protocol following Cochrane rapid review methods and aligned to the National Standard Treatment Guidelines and Essential Medicines List methodology. We first considered relevant high-quality systematic reviews of randomised controlled trials or observational studies, then (if required) randomised controlled trials to inform time-sensitive or urgent evidence requests, clinical practice, policy, or standard treatment guidelines.

RESULTS

We identified four systematic reviews of observational studies. The two most relevant, up-to-date, and highest-quality reviews were used to inform evidence for critical outcomes. Morphine may increase in-hospital mortality (odds ratio (OR) 1.78; 95% confidence interval (CI) 1.01 - 3.13; low certainty of evidence; six observational studies, n=151 735 participants), resulting in 15 more per 1 000 hospital deaths, ranging from 0 to 40 more hospital deaths. Morphine may result in a large increase in invasive mechanical ventilation (OR 2.72; 95% CI 1.09 - 6.80; low certainty of evidence; four observational studies, n=167 847 participants), resulting in 45 more per 1 000 ventilations, ranging from 2 more to 136 more. Adverse events and hospital length of stay were not measured across reviews or trials.

CONCLUSION

Based on the most recent, relevant and best-available quality evidence, morphine use in adults with APE may increase in-hospital and all-cause mortality and may result in a large increase in the need for invasive mechanical ventilation compared to not using morphine. Recommending against the use of morphine in pulmonary oedema may improve patient outcomes. Disinvesting in morphine for this indication may result in cost savings, noting the possible accrued benefits of fewer patients requiring invasive ventilation and management of morphine-related side-effects.

Discomfort improvement for critically ill patients using electronic relaxation devices: results of the cross-over randomized controlled trial E-CHOISIR (Electronic-CHOIce of a System for Intensive care Relaxation)

Purpose

To assess the impact of different electronic relaxation devices on common stressful patient symptoms experienced in intensive care unit (ICU).

Methods

Sixty critically ill patients were enrolled in four relaxation sessions using a randomized cross-over design: standard relaxation (TV/radio), music therapy (MUSIC-CARE©), and two virtual reality systems using either real motion pictures (DEEPSEN©) or synthetic motion pictures (HEALTHY-MIND©). The goal was to determine which device was the best to reduce overall patient discomfort intensity (0–10 Numeric Rating Scale (NRS); primary endpoint). Secondary endpoints were specific stressful symptoms (pain, anxiety, dyspnea, thirst, and lack of rest feeling) and stress response measured by Analgesia/Nociception Index (ANI). Multivariate mixed-effect analysis was used, taking into account patient characteristics and multiple measurements.

Results

Fifty patients followed the full research protocol, and ten patients did at least one research planned session of relaxation. HEALTHY-MIND© was associated with a significant decrease in overall discomfort, the primary endpoint (median NRS = 4[2–6] vs. 2[0–5]; p = 0.01, mixed-effect model), accompanied by a significant decrease in stress response (increase in ANI, secondary endpoint; p < 0.01). Regarding other secondary endpoints, each of the two virtual reality systems was associated with a decrease in anxiety (p < 0.01), while HEALTHY-MIND© was associated also with a decrease in pain (p = 0.001) and DEEPSEN© with a decrease in lack of rest (p = 0.01). Three incidents (claustrophobia/dyspnea/agitation) were reported among 109 virtual reality sessions. Cybersickness was rare (NRS = 0[0–0]).

Conclusion

Electronic relaxation therapy is a promising, safe, and effective non-pharmacological solution that can be used to improve overall discomfort in alert and non-delirious ICU patients. Its effectiveness depends on technical characteristics (virtual reality using a synthetic imagined world versus a real world or music therapy alone without virtual reality), as well as the type of symptoms.

Electronic relaxation therapies are effective supportive care tools for improving stressful symptoms in ICU patients.

Effectiveness depends on the type of symptom and the characteristics of the devices.

Overall discomfort and adrenergic stress response are more significantly improved by virtual reality using a synthetic imagined world than using a real world or music therapy alone.

The impact of reducing opioid unit dose quantities on perioperative utilization and pain scores for laparoscopic cholecystectomies

Aim: At our institution, reductions to hydromorphone and fentanyl unit dose quantities provided us with a unique opportunity to study opioid utilization. Materials & methods: A retrospective study examining effects of changes in opioid unit dose on intra-operative and postoperative opioid utilization in patients who underwent laparoscopic cholecystectomy. The study included three arms: the predosage change (n = 254), fentanyl only change group (n = 102) and the postdosage change arm (n = 254). Results: Decreasing opioid unit dosing decreased intraoperative opioid administration and total perioperative utilization. Decreased postanesthesia care unit morphine milligram equivalent (MME). Requirements were observed in all, but one group comparison. Conclusion: Our data suggests that opioid unit dosing and administration are directly proportional and that decreased intraoperative MME utilization leads to decreased total perioperative MME use.

Dexmedetomidine Use in Infants Undergoing Cooling Due to Neonatal Encephalopathy (DICE Trial): A Randomized Controlled Trial: Background, Aims and Study Protocol

Background: Neonatal hypoxia-ischemia encephalopathy (HIE) is the leading cause of neonatal death and poor neurodevelopmental outcomes worldwide. Therapeutic hypothermia (TH), while beneficial, still leaves many HIE treated infants with lifelong disabilities. Furthermore, infants undergoing TH often require treatment for pain and agitation which may lead to further brain injury. For instance, morphine use in animal models has been shown to induce neuronal apoptosis. Dexmedetomidine is a potent α₂-adrenergic receptor agonist that may be a better alternative to morphine for newborns with HIE treated with TH. Dexmedetomidine provides sedation, analgesia, and prevents shivering but does not suppress ventilation. Importantly, there is increasing evidence that dexmedetomidine has neuroprotective properties. Even though there are limited data on pharmacokinetics (PK), safety and efficacy of dexmedetomidine in infants with HIE, it has been increasingly administered in many centers.

Objectives: To review the current approach to treatment of pain, sedation and shivering in infants with HIE undergoing TH, and to describe a new phase II safety and pharmacokinetics randomized controlled trial that proposes the use of dexmedetomidine vs. morphine in this population.

Methods: This article presents an overview of the current management of pain and sedation in critically ill infants diagnosed with HIE and undergoing TH for 72 h. The article describes the design and methodology of a randomized, controlled, unmasked multicenter trial of dexmedetomidine vs. morphine administration enrolling 50 (25 per arm) neonates ≥36 weeks of gestation with moderate or severe HIE undergoing TH and that require pain/sedation treatment.

Results and Conclusions: Dexmedetomidine may be a better alternative to morphine for the treatment of pain and sedation in newborns with HIE treated with TH. There is increasing evidence that dexmedetomidine has neuroprotective properties in several preclinical studies of injury models including ischemia-reperfusion, inflammation, and traumatic brain injury as well as adult clinical trials of brain trauma. The Dexmedetomidine Use in Infants undergoing Cooling due to Neonatal Encephalopathy (DICE) trial will evaluate whether administration of dexmedetomidine vs. morphine is safe, establish dexmedetomidine optimal dosing by collecting opportunistic PK data, and obtain preliminary neurodevelopmental data to inform a large Phase III efficacy trial with long term neurodevelopment impairment as the primary outcome.

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.

Buprenorphine Analgesia Reduces Survival With ALM Resuscitation in a Rat Model of Uncontrolled Hemorrhage: Concerns for Trauma-Related Research

ABSTRACT

The effect of analgesia on physiological systems has received little attention in trauma research. Our aim was to examine the effect of two different analgesics, buprenorphine and carprofen, on adenosine, lidocaine, and magnesium (ALM) resuscitation in a rat model of laparotomy and non-compressible hemorrhage. Male Sprague-Dawley rats were randomly assigned to Saline Carprieve, ALM Carprieve, Saline Buprenorphine, or ALM Buprenorphine (all n = 10). Anesthetized animals underwent surgical placement of chronic catheters and laparotomy, then hemorrhage was induced by liver resection (60% left lateral lobe). After 15 min, animals received 0.7 mL/kg 3% NaCl ± ALM bolus, and after 60 min, 4 h 0.5 mL/kg/h 0.9% NaCl±ALM drip with 72 h monitoring. Carprieve groups received 5 mg/kg s.c. every 24 h and Buprenorphine groups received 0.05 mg/kg Temgesic every 6 to 12 h. Survival, hemodynamics, blood chemistry, and hematology were measured. ALM Carprieve led to 100% survival compared to 40% survival in ALM Buprenorphine group (P = 0.004). In Saline-treated rats, buprenorphine reduced median survival time by 91% (22 h to 2 h). Recovery of mean arterial pressure (MAP) at 60 min was lower in the buprenorphine versus Carprieve groups (83% vs. 101% for ALM and 62% vs. 95% for Saline groups). Buprenorphine was also associated with higher blood lactates and potassium. No analgesic-related differences were found in total white cells, lymphocytes, platelet count, hyperthermia, weight loss, or pica. We conclude that reduced survival and MAP recovery appears to a buprenorphine effect on cardiovascular function. Until the underlying mechanisms can be elucidated, buprenorphine should be used with caution in small and possibly large models of trauma and shock.

Dexmedetomidine Pharmacokinetics in Neonates with Hypoxic-Ischemic Encephalopathy Receiving Hypothermia

Dexmedetomidine is a promising sedative and analgesic for newborns with hypoxic-ischemic encephalopathy (HIE) undergoing therapeutic hypothermia (TH). Pharmacokinetics and safety of dexmedetomidine were evaluated in a phase I, single-center, open-label study to inform future trial strategies. We recruited 7 neonates ≥36 weeks' gestational age diagnosed with moderate-to-severe HIE, who received a continuous dexmedetomidine infusion during TH and the 6 h rewarming period. Time course of plasma dexmedetomidine concentration was characterized by serial blood sampling during and after the 64.8 ± 6.9 hours of infusion. Noncompartmental analysis yielded descriptive pharmacokinetic estimates: plasma clearance of 0.760 ± 0.155 L/h/kg, steady-state distribution volume of 5.22 ± 2.62 L/kg, and mean residence time of 6.84 ± 3.20 h. Naive pooled and population analyses according to a one-compartment model provided similar estimates of clearance and distribution volume. Overall, clearance was either comparable or lower, distribution volume was larger, and mean residence time or elimination half-life was longer in cooled newborns with HIE compared to corresponding estimates previously reported for uncooled (normothermic) newborns without HIE at comparable gestational and postmenstrual ages. As a result, plasma concentrations in cooled newborns with HIE rose more slowly in the initial hours of infusion compared to predicted concentration-time profiles based on reported pharmacokinetic parameters in normothermic newborns without HIE, while similar steady-state levels were achieved. No acute adverse events were associated with dexmedetomidine treatment. While dexmedetomidine appeared safe for neonates with HIE during TH at infusion doses up to 0.4 μg/kg/h, a loading dose strategy may be needed to overcome the initial lag in rise of plasma dexmedetomidine concentration.

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.

Plasma and Cerebrospinal Fluid Beta-Endorphin Levels Show a Strong Association in Children with Cerebral Malaria

BACKGROUND

Beta (β)-endorphins are endogenous neuropeptides found in the plasma and cerebrospinal fluid (CSF) of humans but there have been reports of the relationship between the plasma and CSF β-endorphin levels in different clinical conditions. However, the relationship between β-endorphin levels in the plasma and CSF of children with cerebral malaria (CM) has not been reported.

AIM

To determine the relationship between β-endorphin levels in the CSF and plasma of children with CM.

SETTINGS AND DESIGN

This cross-sectional study involved 40 children, aged between 6 months and 14 years, admitted with a diagnosis of CM at the Obafemi Awolowo University Teaching Hospitals Complex (OAUTHC), Ile-Ife, Nigeria.

MATERIALS AND METHODS

One milliliter (mL) of venous blood and 1mL of CSF obtained from each subject at admission were used to determine the β-endorphin levels using enzyme-linked immunosorbent assay (ELISA) method.

STATISTICAL ANALYSIS

Bivariate linear regression was used to determine the association between plasma and CSF β-endorphin levels using the correlation coefficient (r), coefficient of determination (R 2), and P values.

RESULTS

The plasma β-endorphin levels significantly positively correlated with CSF β-endorphin (r = 0.568, P = 0.001) such that for every unit rise in plasma β-endorphin, CSF β-endorphin rose by 0.252 pmol/L (confidence interval: 0.132-0.371 pmol/L).

CONCLUSION

The finding of positive correlation between plasma and CSF β-endorphin levels in this study suggests a possible direct link between plasma and CSF in CM, probably from the disruption of the blood-brain barrier that has been reported in CM.

Dynamic lateral organization of opioid receptors (kappa, muwt and muN40D ) in the plasma membrane at the nanoscale level

Opioid receptors are important pharmacological targets for the management of numerous medical conditions (eg, severe pain), but they are also the gateway to the development of deleterious side effects (eg, opiate addiction). Opioid receptor signaling cascades are well characterized. However, quantitative information regarding their lateral dynamics and nanoscale organization in the plasma membrane remains limited. Since these dynamic properties are important determinants of receptor function, it is crucial to define them. Herein, the nanoscale lateral dynamics and spatial organization of kappa opioid receptor (KOP), wild type mu opioid receptor (MOPwt ), and its naturally occurring isoform (MOPN40D ) were quantitatively characterized using fluorescence correlation spectroscopy and photoactivated localization microscopy. Obtained results, supported by ensemble-averaged Monte Carlo simulations, indicate that these opioid receptors dynamically partition into different domains. In particular, significant exclusion from GM1 ganglioside-enriched domains and partial association with cholesterol-enriched domains was observed. Nanodomain size, receptor population density and the fraction of receptors residing outside of nanodomains were receptor-specific. KOP-containing domains were the largest and most densely populated, with the smallest fraction of molecules residing outside of nanodomains. The opposite was true for MOPN40D . Moreover, cholesterol depletion dynamically regulated the partitioning of KOP and MOPwt , whereas this effect was not observed for MOPN40D .

Opioids and immunosupression in oncological postoperative patients

INTRODUCTION

Recent animal studies demonstrated immunosuppressive effects of opioid withdrawal resulting in a higher risk of infection. The aim of this study was to determine the impact of remifentanil discontinuation on Post-Anesthesia Care Unit (PACU)-acquired infection after a schedule of sedoanalgesia of at least 6 days.

METHOD

All patients over 18 years of age with a unit admission of more than 4 days were consecutively selected. The study population was the one affected by surgical pathology of any origin where sedation was based on any hypnotic and the opioid remifentanil was used as analgesic for at least 96 hours in continuous perfusion. Patients who died during admission to the unit and those with combined analgesia (peripheral or neuroaxial blocks) were excluded. Bivariate analysis was performed to determine risk factors for infection acquired in the unit. A comparative study between periods of 6 days before and after the cessation of remifentanil was performed. Paired samples test and McNemar test was used for quantitative and categorical variables, respectively.

RESULTS

There were 1,789 patients admitted to the PACU during the study and the population eligible was constituted for 102 patients. The incidence rate of PACU-acquired infection was 38 per 1,000 PACU days. Ventilator-associated pneumonia was the most frequently diagnosed PACU-acquired infection. Pseudomona aeruginosa was the most frequently isolated microorganism. Hospital mortality was 36.27%. No statistically significant differences were seen in the incidence of HAI in cancer patients in relation to discontinuation of remifentanil (p=0.068).

CONCLUSION

The baseline state of immunosuppression of cancer patients does not imply a higher incidence of HAI in relation to the interruption of remifentanil. It would be of interest to carry out a multicenter PACU study that included immunological patterns.

Cerebrospinal fluid and plasma β-endorphin levels in children with cerebral malaria

OBJECTIVES

Cerebral malaria (CM) is the most lethal form of malaria, yet its pathogenesis is not fully understood. Cytoadherence, sequestration, alterations in cytokine expression, inflammation, and microvascular obstruction are all hypothesized to be important in the aetio-pathogenesis of coma which characterizes cerebral malaria and the death which sometimes result. Beta (β)-endorphin has been postulated to be involved in the pathogenetic processes of inflammation and cytokine expression, although the exact role is unknown. The aim of this study was to determine the levels of β-endorphin in cerebrospinal fluid (CSF) and plasma of children with CM and compare the levels of β-endorphin in the plasma of children with CM with that of apparently healthy age- and sex-matched controls at Ile-Ife, Nigeria.

MATERIALS AND METHODS

Additional to the standard investigation for CM, CSF and venous blood samples were obtained from the subjects for the determination of β-endorphin levels.

RESULTS

Forty children with CM were studied along with forty age- and sex-matched controls. The mean CSF β-endorphin (± SD) level for the children with CM was 1.8 ± 0.9 pmol/L. The mean plasma β-endorphin levels at admission (3.1 ± 2.0 pmol/L) and discharge (4.1 ± 3.3 pmol/L) were higher in children with CM than in the control subjects (2.7 ± 0.7 pmol/L). However, only the mean plasma β-endorphin levels at discharge was significantly higher than that of controls (p = .012).

CONCLUSION

Children with CM had higher mean plasma β-endorphin levels compared to the controls and there was increased production of β-endorphins in children with CM during the course of the illness.

Considerations for analgosedation and antithrombotic management during extracorporeal life support

Despite the immense growth in extracorporeal life support (ECLS) technology and experience, opportunity remains to better characterize the pharmacotherapeutic considerations during ECLS. Analgosedation can be particularly challenging in the ECLS population due to in drug-circuit interactions that may lead to decreased systemic concentrations and pharmacodynamic effect. ECLS also requires the use of antithrombotic agents to mitigate the prothrombotic state created by the artificial surface in the ECLS circuit. There are a number of coagulation monitoring tests available. However, optimal monitoring and management in ECLS has not been established. Heparin continues to be the anticoagulant of choice for most ECLS centers, however, there is growing interest in the use of parenteral direct thrombin inhibitors (DTI) in this population. Advances in understanding pharmacotherapeutic management have not kept up with the technological advances in this population. More investigation is warranted to gain a greater understanding of the pharmacotherapeutic implications, facilitate standardized evidence-based practices, and improve patient centered outcomes.

Methadone analgesia in the critically ill

PURPOSE

Methadone is increasingly used as an analgesic or a bridge to weaning other analgesics and sedatives in critically ill patients. This review discusses the pharmacology of methadone, summarizes available evidence for its use in the intensive care unit setting, and makes suggestions for appropriate use and monitoring.

MATERIALS/METHODS

Articles evaluating the efficacy, safety, and pharmacology of methadone were identified from a PubMed search through June 2015. References from selected articles were reviewed for additional material. Experimental and observational English-language studies that focused on the efficacy, safety, and pharmacology of methadone in critically-ill adults and children were selected.

RESULTS

Methadone is a synthetic opioid analgesic with potential advantages over other commonly used opioids. Limited evidence from critically ill pediatric, adult, and burn populations suggests that methadone protocols may expedite weaning opiate infusions, decrease the length of mechanical ventilation, and reduce the incidence of negative outcomes such as opiate withdrawal, delirium, and over-sedation.

CONCLUSIONS

Data from current literature supports a role for methadone analgesia in weaning opiates and potentially reducing the duration of mechanical ventilation in critically ill patients. More studies are needed to confirm these benefits and determine criteria for patient selection.

Modulation of voltage-gated Ca2+ channels by G protein-coupled receptors in celiac-mesenteric ganglion neurons of septic rats

Septic shock, the most severe complication associated with sepsis, is manifested by tissue hypoperfusion due, in part, to cardiovascular and autonomic dysfunction. In many cases, the splanchnic circulation becomes vasoplegic. The celiac-superior mesenteric ganglion (CSMG) sympathetic neurons provide the main autonomic input to these vessels. We used the cecal ligation puncture (CLP) model, which closely mimics the hemodynamic and metabolic disturbances observed in septic patients, to examine the properties and modulation of Ca²⁺ channels by G protein-coupled receptors in acutely dissociated rat CSMG neurons. Voltage-clamp studies 48 hr post-sepsis revealed that the Ca²⁺ current density in CMSG neurons from septic rats was significantly lower than those isolated from sham control rats. This reduction coincided with a significant increase in membrane surface area and a negligible increase in Ca²⁺ current amplitude. Possible explanations for these findings include either cell swelling or neurite outgrowth enhancement of CSMG neurons from septic rats. Additionally, a significant rightward shift of the concentration-response relationship for the norepinephrine (NE)-mediated Ca²⁺ current inhibition was observed in CSMG neurons from septic rats. Testing for the presence of opioid receptor subtypes in CSMG neurons, showed that mu opioid receptors were present in ~70% of CSMG, while NOP opioid receptors were found in all CSMG neurons tested. The pharmacological profile for both opioid receptor subtypes was not significantly affected by sepsis. Further, the Ca²⁺ current modulation by propionate, an agonist for the free fatty acid receptors GPR41 and GPR43, was not altered by sepsis. Overall, our findings suggest that CSMG function is affected by sepsis via changes in cell size and α2-adrenergic receptor-mediated Ca²⁺ channel modulation.

Optimal antiarrhythmic drug therapy for electrical storm

Electrical storm, defined as 3 or more separate episodes of ventricular tachycardia or ventricular fibrillation within 24 hours, carries significant morbidity and mortality. These unstable ventricular arrhythmias have been described with a variety of conditions including ischemic heart disease, structural heart disease, and genetic conditions. While implantable cardioverter defibrillator implantation and ablation may be indicated and required, antiarrhythmic medication remains an important adjunctive therapy for these persons.

Endomorphins and ohmefentanyl in the inhibition of immunosuppressant function in rat peritoneal macrophages: An experimental in vitro study

BACKGROUND

The potential immunosuppressant effects of opioids might have clinical implications. The effects of endomorphins (EMs) and ohmefentanyl (OMF) on cultured rat peritoneal macrophages remain unclear.

OBJECTIVE

The aim of this study was to investigate the immunosuppressant effects of EMs and OMF on cultured rat peritoneal macrophages in vitro.

METHODS

Purified rat peritoneal macrophages, from healthy adult male Sprague-Dawley rats, were cultured with EM-1 (EM-1 group), EM-2 (EM-2 group), OMF (OMF group), and saline (saline group). We measured the concentrations of tumor necrosis factor (TNF)-α and interleukin (IL)-β in supernatant when macrophages were cultured with 10(-6) mol/L of EM-1, EM-2, OMF, or saline for 0, 6, 12, and 24 hours (time-effect relationship) or with 10(-10), 10(-9), 10(-8), 10(-7), and 10(-6) mol/L of these substances for 24 hours (concentration-effect relationship). We also determined the phagocytic and bactericidal activities of macrophages using isotope markers when macrophages were cultured with 10(-6) mol/L of EM-1, EM-2, OMF, or saline for 24 hours.

RESULTS

Compared with the saline group, TNF-α concentration decreased significantly in the OMF, EM-2, and EM-1 groups at 12 hours (P < 0.05, P < 0.05, and P < 0.01, respectively) and at 24 hours (P < 0.05, P < 0.01, and P < 0.01, respectively). Compared with the saline group, IL-1β concentration decreased signifcantly in the OMF, EM-2, and EM-1 groups at 12 hours (P < 0.05, P < 0.05, and P < 0.01, respectively) and at 24 hours (P < 0.05, P < 0.01, and P < 0.01, respectively). Decreased TNF-α and IL-1β concentrations were observed in the supernatant at 24 hours when cultured with 10(-8), 10(-7), and 10(-6) mol/L in the OMF and EM-2 groups (all, P < 0.05) and in the EM-1 group (all, P < 0.01). Compared with the saline group, macrophage phagocytic activity (all, P < 0.05) and macrophage bactericidal activity (all, P < 0.01) were significantly lower in the 3 experimental groups compared with the saline group.

CONCLUSION

In this in vitro experiment, EM-1, EM-2, and OMF inhibited the immunosuppressant function of cultured rat peritoneal macrophages, including decreasing TNF-α and IL-1β concentrations and phagocytic and bactericidal activities.

Drug and alcohol use complicate traumatic peripheral vascular injury

BACKGROUND

Drug and alcohol use complicate the presentation and management of traumatic injuries. Impaired hemodynamic recovery and host defense in substance users also predispose these patients to worse outcomes after trauma. We hypothesized that substance abuse, particularly when drugs and alcohol are combined, complicates the presentation, management, and patient outcomes following isolated traumatic peripheral vascular injury.

METHODS

This is a retrospective analysis of patients admitted with isolated peripheral vascular injury to our Level 1 trauma center between 2006 and 2012. Demographics, presentation, substance use, resuscitation, operative management, intensive care needs, and length of hospital stay were analyzed.

RESULTS

From 257 patients admitted, 158 patients experienced isolated peripheral vascular injury. Patients were subdivided by blood alcohol level (BAL) and urinary toxicology (utox) screens; negative BAL/negative utox (nonintoxicated, n = 90), negative BAL/positive utox (drug users, n = 27), positive BAL/negative utox (alcohol users, n = 22), and positive BAL/positive utox (polysubstance users, n = 19). Compared with nonintoxicated patients, more polysubstance users experienced lower-extremity injury (79% vs. 47%) and presented more often than alcohol users with proximal injury (83% vs. 45%), lower-extremity injury (79% vs. 36%), and as a result of assault (68.4% vs. 31.8%). Polysubstance users required greater resuscitation, more operations, and more frequently experienced complications than any other cohort. Subsequently, these patients had a greater need for intensive care management and longer hospital stay than nonintoxicated and alcohol users. Moreover, using multivariate logistic regression analysis, we found that polysubstance use, alcohol use, and lower-extremity injury are each independent risk factors for infectious complications.

CONCLUSION

Our data show that polysubstance users with isolated peripheral vascular injury experience more proximal and lower-extremity injuries, require greater resuscitation, and undergo more operations compared with nonintoxicated patients. Treatment of these patients is more frequently complicated by infection, vascular complications, and increased hospital length of stay.

Hematologic changes in propofol-anesthetized dogs with or without tramadol administration

Drugs commonly used in anesthesia practice may significantly alter the oxidative state of blood cells. This mechanism could contribute to the immune suppression that occurs transiently in the early postoperative period. Thus, we assessed the effects of continuous rate infusion (CRI) of propofol associated or not with tramadol on hematologic parameters in dogs. Eight adult mongrel dogs were anesthetized on 2 occasions, 15 d apart. Two groups were formed: control group (CG) and tramadol group (GT). Propofol was used for induction (10mg kg-1) followed by a CRI (0.7mg kg-1minute-1). The animals were positioned in lateral recumbency and mechanically ventilated with inspired oxygen fraction of 0.6. In TG, tramadol (2mg kg-1) followed by a CRI (0.5mg kg-1minute-1) was administered in dogs. In the CG the sodium chloride (NaCl) solution at 0.9% was administered followed by its CRI, in the same volume that was used in TG. The measurement was taken before anesthesia induction (Tbasal), 30 minutes after induction (T0) and then at 30-minute intervals (T30 to T60). Red blood cells, hematocrit, hemoblogin concentration and total leukocytes count decreased from T0 in both groups. In TG, lymphocytes count at Tbasal [1.86 (0.82) x103µl-1] was greater than at T0, T30 and T60 [0.96(0.50), 0.92(0.48) and 0.95(0.48) x103µl-1, respectively]. No significant differences were observed for platelets neutrophil, eosinophil, basophil and monocyte count. In dogs, propofol-anesthesia associated or not with tramadol promoted decrease in blood cell count and should be used with caution in immunossupressed patients.

Remifentanil/midazolam versus fentanyl/midazolam for analgesia and sedation of mechanically ventilated neonates and young infants: a randomized controlled trial

PURPOSE

Common opioids for analgesia and sedation of mechanically ventilated infants may tend to accumulate and cause prolonged sedation with an unpredictable extubation time. Remifentanil is a promising option due to its unique pharmacokinetic properties, which seem to be valid in adults as well as in infants.

METHODS

In this double-blind, randomized, controlled trial mechanically ventilated neonates and young infants (<60 days) received either a remifentanil or fentanyl-based analgesia and sedation regimen with low dose midazolam. The primary endpoint of the trial was the extubation time following discontinuation of the opioid infusion. Secondary endpoints included efficacy and safety aspects.

RESULTS

Between November 2006 and March 2010, we screened 431 mechanically ventilated infants for eligibility. The intention to treat group included 23 infants who were assigned to receive either remifentanil (n = 11) or fentanyl (n = 12). Although this was designed as a pilot study, median extubation time was significantly shorter in the remifentanil group (80.0 min, IQR = 15.0-165.0) compared to the fentanyl group (782.5 min, IQR = 250.8-1,875.0) (p = 0.005). Remifentanil and fentanyl provided comparable efficacy with more than two-thirds of the measurements indicating optimal analgesia and sedation (66.4 and 70.2 %, respectively; p = 0.743). Overall, both groups had good hemodynamic stability and a comparably low incidence of adverse events.

CONCLUSIONS

As neonates and young infants have a decreased metabolism of common opioids like fentanyl and are more prone to respiratory depression, remifentanil could be the ideal opioid for analgesia and sedation of mechanically ventilated infants.

Cannabinoid neuroimmune modulation of SIV disease

Marijuana is one of the most commonly used and abused drugs. Δ-9-tetrahydrocannabinol (Δ-9-THC), the primary psychoactive component in marijuana, is FDA-approved to ameliorate AIDS-associated wasting. Because cannabinoid receptors are expressed on cells of the immune system, it is possible that chronic Δ-9-THC use may impact HIV disease progression. Until recently, longitudinal, controlled, systems-approach studies on the effects of cannabinoids on disease progression were lacking. Data from our controlled studies in non-human primates show chronic Δ-9-THC administration prior to and during simian immunodeficiency virus (SIV) infection ameliorates disease progression, attenuates viral load and tissue inflammation, significantly reducing morbidity and mortality of SIV-infected macaques. Identification of possible mechanisms responsible for this modulation of disease progression is complicated due to the multiplicity of cannabinoid-mediated effects, tissue-specific responses to the viral infection, multiple cellular mechanisms involved in inflammatory responses, coordinated neuroendocrine and localized responses to infection, and kinetics of viral replication. Emerging results from our studies reveal that the overall mechanisms mediating the protective effects of cannabinoids involve novel epigenomic regulatory mechanisms in need of systematic investigation. Here, we review the evidence supporting an immunomodulatory role for cannabinoids and its impact on disease progression with focus on HIV/SIV infection.

Neuropeptides as pleiotropic modulators of the immune response

Although necessary to eliminate pathogens, inflammation can lead to serious deleterious effects in the host if left unchecked. During the inflammatory response, further damage may arise from potential autoimmune responses occurring when the immune cells and molecules that respond to pathogen-derived antigens also react to self-antigens. In this sense, the identification of endogenous factors that control exacerbated immune responses is a key goal for the development of new therapeutic approaches for inflammatory and autoimmune diseases. Some neuropeptides that are produced during the ongoing inflammatory response have emerged as endogenous anti-inflammatory agents that could collaborate in tuning the balanced steady state of the immune system. These neuropeptides participate in maintaining immune tolerance through two distinct mechanisms: by regulating the balance between pro-inflammatory and anti-inflammatory factors, and by inducing the emergence of regulatory T cells with suppressive activity against autoreactive T cell effectors. Indeed, a functioning neuropeptide system contributes to general health, and alterations in the levels of these neuropeptides and/or their receptors lead to changes in susceptibility to inflammatory and autoimmune diseases. Recently, we found that some neuropeptides also have antimicrobial and antiparasitic actions, suggesting that they could act as primary mediators of innate defense, even in the most primitive organisms. In this review, we use the vasoactive intestinal peptide as example of an immunomodulatory neuropeptide to summarize the most relevant data found for other neuropeptides with similar characteristics, including adrenomedullin, urocortin, cortistatin and ghrelin.

Immunology as it pertains to drugs of abuse, AIDS and the neuroimmune axis: mediators and traffic

The interactions between the immune and nervous systems are very complex, and yet our understanding of these interactions is still relatively limited. The neuroinflammatory reaction that can accompany HIV infection occurs because of a cascade of events that appears to require the migration of HIV-infected cells across the blood-brain barrier. In susceptible individuals, this leads to inflammatory processes which can include substantial changes in neuronal function. It is possible to consider the inflammatory events to be composed of two essential processes. The first process is cellular traffic, and the second, is the expression and recognition of the various pro-inflammatory and/or toxic mediators. The added complication of drug abuse adds complexity to the traffic and mediator release events, and depending on the specific drug being abused, the disease can be exacerbated in these individuals. An understanding of the fine details of these mediator and traffic processes should provide useful targets for therapeutic intervention to attenuate disease associated with HIV infection.

Assessment of nociceptin/orphanin FQ and micro-opioid receptor mRNA in the human right atrium

BACKGROUND

The expression of micro (mu: MOP) and nociceptin/orphanin FQ (NOP) receptors in the human myocardium is controversial. In this polymerase chain reaction (PCR)-based study using human right atrial biopsies, we have (i) probed for mRNA encoding NOP receptor and its endogenous peptide precursor, ppN/OFQ, and mRNA encoding MOP and (ii) attempted to correlate expression with cardiac function.

METHODS

mRNA encoding MOP, NOP, and the precursor for NOP (ppN/OFQ) was assessed by quantitative real-time PCR (Q-PCR) using validated TaqMan primers and compared with a housekeeper (glyceraldehyde-3-phosphate dehydrogenase, GAPDH). Q-PCR data are expressed as the difference in cycle threshold (DeltaC(t)=C(tGene of interest)-C(tGAPDH): high value, low expression) and patients were grouped according to left ventricular ejection fraction (LVEF).

RESULTS

Forty patients were recruited; NOP, MOP, and ppN/OFQ mRNA were measured in 38, 29, and 10 patients, respectively. DeltaC(t) (median and range) values for NOP and MOP were 10.9 (7.8-13.7) and 16.0 (12.3-18.9), respectively, representing low expression of MOP and approximately 34-fold more NOP. MOP mRNA was not detected in seven samples and with DeltaC(t) values of approximately 20, ppN/OFQ was considered absent. When patients were grouped into normal (>50%) and impaired (<50%) LVEF, there was no difference between the groups for either NOP or MOP. In some patients, intraoperative LVEF was estimated using transoesophageal echocardiography, and there was no correlation with either NOP or MOP.

CONCLUSIONS

The human right atrium of patients with coronary artery disease and heart failure expresses mRNA encoding NOP and possibly low levels of MOP. This does not correlate with degree of cardiac dysfunction. In addition, the atrium does not express ppN/OFQ mRNA.

Sympathetic overstimulation during critical illness: adverse effects of adrenergic stress

The term ''adrenergic'' originates from ''adrenaline'' and describes hormones or drugs whose effects are similar to those of epinephrine. Adrenergic stress is mediated by stimulation of adrenergic receptors and activation of post-receptor pathways. Critical illness is a potent stimulus of the sympathetic nervous system. It is undisputable that the adrenergic-driven ''fight-flight response'' is a physiologically meaningful reaction allowing humans to survive during evolution. However, in critical illness an overshooting stimulation of the sympathetic nervous system may well exceed in time and scope its beneficial effects. Comparable to the overwhelming immune response during sepsis, adrenergic stress in critical illness may get out of control and cause adverse effects. Several organ systems may be affected. The heart seems to be most susceptible to sympathetic overstimulation. Detrimental effects include impaired diastolic function, tachycardia and tachyarrhythmia, myocardial ischemia, stunning, apoptosis and necrosis. Adverse catecholamine effects have been observed in other organs such as the lungs (pulmonary edema, elevated pulmonary arterial pressures), the coagulation (hypercoagulability, thrombus formation), gastrointestinal (hypoperfusion, inhibition of peristalsis), endocrinologic (decreased prolactin, thyroid and growth hormone secretion) and immune systems (immunomodulation, stimulation of bacterial growth), and metabolism (increase in cell energy expenditure, hyperglycemia, catabolism, lipolysis, hyperlactatemia, electrolyte changes), bone marrow (anemia), and skeletal muscles (apoptosis). Potential therapeutic options to reduce excessive adrenergic stress comprise temperature and heart rate control, adequate use of sedative/analgesic drugs, and aiming for reasonable cardiovascular targets, adequate fluid therapy, use of levosimendan, hydrocortisone or supplementary arginine vasopressin.

Effects of intravitreal morphine administered at different time points after reperfusion in a rabbit model of ischemic retinopathy

PURPOSE

To investigate the effects of morphine administered after reperfusion in a rabbit model of ischemic retinopathy.

METHODS

The right eyes of 54 albino New Zealand rabbits were randomly allocated into nine treatment groups (n = 6 in each group). The eyes in saline-control group received 0.1 mL of phosphate-buffered saline solution intravitreally. In the ischemia-saline group, ischemia was induced by raising the intraocular pressure to 150 mmHg for 60 minutes. Then 0.1 mL of phosphate-buffered saline solution was administered intravitreally 5 minutes after reperfusion. The eyes in three ischemia-morphine groups (ischemia-morphine 0 hour, 1 hour, and 18 hours) received 0.1 mL of morphine (10 micromol/L) intravitreally 5 minutes, 1 hour, or 18 hours after termination of 60 minutes of ischemia, respectively. The eyes in ischemia-naloxone-morphine group received 0.05 mL of naloxone (10 micromol/L) intravitreally followed by injection of 0.05 mL morphine (10 micromol/L) 5 minutes after termination of ischemia. Toxicity controls were performed with morphine (10 micromol/L) and naloxone (10 micromol/L) without ischemia. Histologic evaluation was performed for all groups on the seventh postoperative day.

RESULTS

Sixty minutes of ischemia led to severe cell loss in ganglion cell layer and thinning of the inner nuclear layer in ischemia-saline group compared with that of the saline-control group (P < 0.001). Thickness of the inner plexiform layer to the inner limiting membrane (a measure of inner retinal thickness) was significantly increased due to edema (P < 0.001). Administration of morphine 5 minutes after reperfusion significantly improved all of the above mentioned indices compared with ischemia-saline group (P < 0.001). Administration of morphine 1 hour after reperfusion had also a significant effect on the improvement of above mentioned indices compared with saline-control group (P < 0.05). However, the number of ganglion cells was significantly higher in ischemia-morphine 0 hour group compared with ischemia-morphine 1 hour group (P < 0.001). Morphine treatment 18 hours after reperfusion did not change the amount of injury. Administration of naloxone 5 minutes before morphine abolished most of the morphine protective effects.

CONCLUSION

Intravitreal administration of morphine immediately after reperfusion maximally protects retina against ischemia-reperfusion injury. Pharmacologic evidence suggests that this protective phenomenon may be mediated in part by opioid receptors.

Opioidergic and dopaminergic modulation of respiration

Opioids, dopamine and their receptors are present in many regions of the bulbar respiratory network. The physiological importance of endogenous opioids to respiratory control has not been explicitly demonstrated. Nonetheless, studies of opioidergic respiratory mechanisms are important because synthetic opiate drugs have respiratory side effects that in some situations pose health risks and limit their therapeutic usefulness. They can depress breathing depth and rate, blunt respiratory responsiveness to CO2 and hypoxia, increase upper airway resistance and reduce pulmonary compliance. The opiate respiratory disturbances are mainly due to agonist activation of mu- and delta-subtypes of receptor and involve specific types of respiratory-related neurons in the ventrolateral medulla and the dorsolateral pons. Endogenous dopaminergic modulation in the CNS and carotid bodies enhances CO2-dependent respiratory drive and depresses hypoxic drive. In the CNS, synthetic agonists with selectivity for D1-and D4-types of receptor slow respiratory rhythm, whereas D2-selective agonists modulate acute and chronic responses to hypoxia. D1-receptor agonists also act centrally to increase respiratory responsiveness to CO2, and counteract opiate blunting of CO2-dependent respiratory drive and depression of breathing. Cellular targets and intracellular mechanisms responsible for opioidergic and dopaminergic respiratory effects for the most part remain to be determined.

Endogenous anti-inflammatory neuropeptides and pro-resolving lipid mediators: a new therapeutic approach for immune disorders

Identification of the factors that regulate the immune tolerance and control the appearance of exacerbated inflammatory conditions is crucial for the development of new therapies of inflammatory and autoimmune diseases. Although much is known about the molecular basis of initiating signals and pro-inflammatory chemical mediators in inflammation, it has only recently become apparent that endogenous stop signals are critical at early checkpoints within the temporal events of inflammation. Some neuropeptides and lipid mediators that are produced during the ongoing inflammatory response have emerged as endogenous anti-inflammatory agents that participate in the regulation of the processes that ensure self-tolerance and/or inflammation resolution. Here we examine the latest research findings, which indicate that neuropeptides participate in maintaining immune tolerance in two distinct ways: by regulating the balance between pro-inflammatory and anti-inflammatory factors, and by inducing the emergence of regulatory T cells with suppressive activity against autoreactive T-cell effectors. On the other hand, we also focus on lipid mediators biosynthesized from omega-3 and omega-6 polyunsaturated fatty-acids in inflammatory exudates that promote the resolution phase of acute inflammation by regulating leucocyte influx to and efflux from local inflamed sites. Both anti-inflammatory neuropeptides and pro-resolving lipid mediators have shown therapeutic potential for a variety of inflammatory and autoimmune disorders and could be used as biotemplates for the development of novel pharmacologic agents.

Electromagnetic millimeter wave induced hypoalgesia: frequency dependence and involvement of endogenous opioids

Millimeter wave treatment (MMWT) is based on the systemic biological effects that develop following local skin exposure to low power electromagnetic waves in the millimeter range. In the present set of experiments, the hypoalgesic effect of this treatment was analyzed in mice. The murine nose area was exposed to MMW of "therapeutic" frequencies: 42.25, 53.57, and 61.22 GHz. MMWT-induced hypoalgesia was shown to be frequency dependent in two experimental models: (1) the cold water tail-flick test (chronic non-neuropathic pain), and (2) the wire surface test (chronic neuropathic pain following unilateral constriction injury to the sciatic nerve). Maximum hypoalgesic effect was obtained when the frequency was 61.22 GHz. Other exposure parameters were: incident power density = 13.3 mW/cm(2), duration of each exposure = 15 min. Involvement of delta and kappa endogenous opioids in the MMWT-induced hypoalgesia was demonstrated using selective blockers of delta- and kappa-opioid receptors and the direct ELISA measurement of endogenous opioids in CNS tissue. Possible mechanisms of the effect and the perspectives of the clinical application of MMWT are discussed.

Morphine pretreatment provides histologic protection against ischemia-reperfusion injury in rabbit retina

PURPOSE

Pharmacologic preconditioning with morphine has been shown to protect several kinds of tissues against ischemia-reperfusion injury. The aim of the present study was to investigate whether intravitreal administration of morphine induces structural protection against ischemic damage in a rabbit model of ischemic retinopathy.

METHODS

Twenty-eight male white New Zealand rabbits were used. Animals in saline control group received 0.1 mL of phosphate-buffered saline (PBS) intravitreally with no postinjection ischemia. In the saline-control ischemia group, 15 minutes after injection of PBS, retinal ischemia was induced by raising intraocular pressure to 150 mmHg for 60 minutes. In three treatment-ischemia groups, morphine (1, 5, and 10 micromol/L) was administered intravitreally 15 minutes before induction of ischemia. In another experiment, naloxone (40 micromol/L) was administered 5 minutes before intravitreal administration of morphine (10 micromol/L) followed by 60 minutes of ischemia to investigate the role of opioid receptors in mediating the possible protective effect of morphine. Toxicity controls were performed with morphine (10 micromol/L) and naloxone (40 micromol/L) without ischemia. Histologic evaluation was performed for all groups on the seventh postoperative day.

RESULTS

Sixty minutes of ischemia led to severe cell loss in ganglion cell layer and thinning of the inner nuclear layer in saline-control ischemia compared to that of the nonischemia control group (P < 0.001). Thickness of the inner plexiform layer to the inner limiting membrane was significantly increased due to edema (P < 0.001). Administration of morphine in higher doses (5 and 10 micromol/L) significantly improved all of the above mentioned indices (P < 0.05). Administration of naloxone 15 minutes before morphine reversed most of the morphine protective effects.

CONCLUSIONS

Morphine pretreatment provides significant histologic protection against ischemic injury in rabbit retina. Pharmacologic evidence suggests that this protective phenomenon may be mediated in part by opiate receptors.

Urinary cortisol and catecholamine excretion after burn injury in children

INTRODUCTION

A severe burn causes increased levels of urine cortisol and catecholamines. However, little is known about the magnitude of this increase or how and when the levels return to normal. The purpose of this study was to determine in a large clinical prospective trial the acute and long-term pattern of urine cortisol and catecholamine expression in severely burned children.

METHODS

Pediatric patients with burns greater than 40% total body surface area (TBSA), admitted to our unit over a 6-yr period, were included into the study. Clinical data including length of stay, number of operations, and duration and number of infections were determined. Patients had regular 24-h urine collections during their acute admission and reconstructive periods. Urine collections were analyzed for cortisol, epinephrine, and norepinephrine. Each urine cortisol was compared with age-adjusted reference ranges. Ninety-five percent confidence intervals and ANOVA analysis were used where appropriate.

RESULTS

Two hundred twelve patients were included in the study (75 females and 137 males), with a mean +/- sem TBSA of 58 +/- 1% (third-degree 45 +/- 2%) and mean age of 9 +/- 0.4 yr. Urinary cortisol levels were significantly increased (3- to 5-fold) up to 100 d after the burn and then approached normal levels (P < 0.05). The rise in urine cortisol was significantly higher in male than female patients (P < 0.05). Early hypercortisolemia was associated with increased duration of severe infection (P < 0.05). Persistent hypercortisolemia was associated with increases in both infection rates and duration of severe infection (P < 0.05). Urinary catecholamines showed a significant increase at 11-20 d after the burn (P < 0.05). Urinary norepinephrine levels were significantly increased up to 20 d and then returned to normal (P < 0.05).

CONCLUSIONS

Urinary levels of cortisol, epinephrine, and norepinephrine are significantly increased after a major burn. Early hypercortisolemia is associated with increased duration of severe infection. Persistent hypercortisolemia is associated with increases in both infection rates and duration of severe infection.

Enkephalin-encoding herpes simplex virus-1 decreases inflammation and hotplate sensitivity in a chronic pancreatitis model

Background

A chronic pancreatitis model was developed in young male Lewis rats fed a high-fat and alcohol liquid diet beginning at three weeks. The model was used to assess time course and efficacy of a replication defective herpes simplex virus type 1 vector construct delivering human cDNA encoding preproenkephalin (HSV-ENK).

Results

Most surprising was the relative lack of inflammation and tissue disruption after HSV-ENK treatment compared to the histopathology consistent with pancreatitis (inflammatory cell infiltration, edema, acinar cell hypertrophy, fibrosis) present as a result of the high-fat and alcohol diet in controls. The HSV-ENK vector delivered to the pancreatic surface at week 3 reversed pancreatitis-associated hotplate hypersensitive responses for 4–6 weeks, while control virus encoding β-galactosidase cDNA (HSV-β-gal) had no effect. Increased Fos expression seen bilaterally in pain processing regions in control animals with pancreatitis was absent in HSV-ENK-treated animals. Increased met-enkephalin staining was evident in pancreas and lower thoracic spinal cord laminae I–II in the HSV-ENK-treated rats.

Conclusion

Thus, clear evidence is provided that site specific HSV-mediated transgene delivery of human cDNA encoding preproenkephalin ameliorates pancreatic inflammation and significantly reduces hypersensitive hotplate responses for an extended time consistent with HSV mediated overexpression, without tolerance or evidence of other opiate related side effects.