Morphine postconditioning attenuates ICAM-1 expression on endothelial cells

The Reasons for Higher Mortality Rate in Opium Addicted Patients with COVID-19: A Narrative Review

The outbreak of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) caused COVID-19 has developed into an unexampled worldwide pandemic. The most important cause of death in patients with COVID-19 is Acute Respiratory Distress Syndrome (ARDS). Opium is widely used for its analgesic features in control of acute and chronic pain related to different diseases. Opium consumption is increased over the last three decades and leads to adverse effects on the respiratory system; opium also affects the lungs' functions and respiration. The contemplative issue is the higher mortality rate due to SARS-CoV-2 infection in opium addicts' patients. Studies have shown that despite the decrease in proinflammatory cytokines production in opium addicts, there are at least 4 reasons for this increase in mortality rate: downregulation of IFNs expression, development of pulmonary edema, increase thrombotic factors, increase the expression of Angiotensin-converting enzyme 2 (ACE2). Therefore, identifying the causes of mortality and approved therapies for the treatment of COVID-19 patients who use opium for any reason is an important unmet need to reduce SARS-CoV-2 infection-related mortality. This review study demonstrated the effects of opium on immune responses and the reasons for the higher mortality rate in opium addicts' patients with COVID-19.

Morphine post-conditioning-induced up-regulation of lncRNA TINCR protects cardiomyocytes from ischemia-reperfusion injury via inhibiting degradation and ubiquitination of FGF1

BACKGROUND

Our previous study has demonstrated that morphine post-conditioning (MpostC) protects cardiomyocytes from ischemia/reperfusion (I/R) injury partly through activating protein kinase-epsilon (PKCε) signaling pathway and subsequently inhibiting mitochondrial permeability transition pore (mPTP) opening.

AIM

In this study, we aim to investigate the relationship between long non-coding RNA TINCR and PKCε in cardiomyocytes under MpostC-treated I/R injury.

DESIGN

The myocardial I/R rat model was established by the ligation of lower anterior descending coronary artery for 45 min followed by the reperfusion for 1 h, and MpostC was performed before the reperfusion.

METHOD

H/R and MpostC were performed in the rat cardiomyocyte cell line (H9C2), and the Cytochrome-c release in cytosol and mPTP opening were determined. Cell viability was detected by using Cell Counting Kit-8, and cell apoptosis was determined by using flow cytometry or TUNEL assay.

RESULTS

The results indicated that MpostC restored the expression of TINCR in I/R rat myocardial tissues. In cardiomyocytes, the therapeutic effect of MpostC, including reduced mPTP opening, reduced Cytochrome-c expression, increased cell viability and reduced cell apoptosis, was dramatically negated by interfering TINCR. The expression of fibroblast growth factor 1 (FGF1), a protein that activates PKCε signaling pathway, was positively correlated with TINCR. The RNA immunoprecipitation and RNA pull-down assay further confirmed the binding between FGF1 and TINCR. Furthermore, TINCR was demonstrated to inhibit the degradation and ubiquitination of FGF1 in cardiomyocytes using the cycloheximide experiment and the ubiquitination assay. The TINCR/FGF1/PKCε axis was revealed to mediate the protective effect of MpostC against hypoxia/reoxygenation injury both in vitro and in vivo.

CONCLUSION

In conclusion, our findings demonstrated that MpostC-induced up-regulation of TINCR protects cardiomyocytes from I/R injury via inhibiting degradation and ubiquitination of FGF1, and subsequently activating PKCε signaling pathway, which provides a novel insight in the mechanism of TINCR and PKCε during MpostC treatment of I/R injury.

Perioperative Immunosuppression and Risk of Cancer Progression: The Impact of Opioids on Pain Management

Opioids comprise an important group of drugs used in cancer pain pharmacotherapy. In recent years, more and more studies have emerged indicating the potentially immunosuppressive effects of opioid analgesics and their serious consequences, including the risk of cancer progression. The identification of these risks has prompted a search for other effective, and most importantly, safer methods of perioperative analgesic management. Regional analgesia techniques, which allow for a significant reduction in opioid dosing and thus diminish the risk of immunosuppression associated with these drugs, seem to offer substantial hope in this respect. A number of studies available in the literature assess the effects of regional analgesia techniques on cancer progression; however, it is often difficult to interpret their results owing to several perioperative factors (such as surgical trauma, inadequate pain and stress relief, and hypothermia) which are also attributed immunosuppressive effects and tend to be implicated in increased risk of cancer progression. Further research is needed to verify the available data on both the potential adverse effects of opioids and the possible protective effects of regional analgesia techniques on cancer patients.

Opioids in Cardiovascular Disease: Therapeutic Options

The World Health Organization suggests that the cardiovascular diseases (CVDs) are the major cause of mortality and account for two-thirds of the deaths all over the world. These diseases kill about 17 million people every year and 3 in every 10 deaths are due to these diseases. The past decade has seen considerable improvements in diagnosis as well as treatment of various heart diseases. Various new therapeutic targets are being identified through in-depth knowledge of the disease mechanisms which has favored the testing of new strategies leading to newer treatment options. Opioid peptides and G-protein-coupled opioid receptors (ORs) have been previously studied widely in terms of central nervous system actions in mitigating the pain and drug abuse. The OR agonism or antagonism induces cytoprotective states in the myocardium, rendering these receptors as an attractive target for protection of heart from the fatal heart diseases. The opioids can provide an extended window of protection of the heart from various diseases. Although the mechanisms may not be fully understood, they seem to play a crucial role in various CVDs such as hypertension, hyperlipidemia, ischemic heart disease myocardial ischemia, and congestive heart failure. Since these compounds are already being used in acute and chronic pain, soon these compounds might be approved for use as cardioprotective agents. The following review focuses on the new information acquired on the role of the ORs in various CVDs.

The protective effect of hydromorphone to ischemia in rat glial cells

BACKGROUND

Ischemic insults during operation can cause ischemic-reperfusion injuries in brain as well as memory impairments. Total intravenous anesthesia (TIVA) is the preferred anesthetic method in brain surgery, as it utilizes motor evoked potential monitoring. And the use of opioids is common in TIVA. However there are few studies about ischemic protective effect of opioids to glial cells.

METHODS

We used mixed cultures of rat glial cells, which were harvested from the brain of 1-day old rat. We divided the experimental groups according to their hydromorphone conditioning period: (a) pre-culture, (b) per-culture, or (c) pre- and per-culture. We measured the levels of the reactive oxygen species (ROS) induced by tert-butyl hydroperoxide (TBH) using flow cytometry. The ROS levels in the glial cells were also measured after the administration of 100 nM hydromorphone and selective opioid receptor antagonists.

RESULTS

The ROS levels were reduced in the hydromorphone-treated group, as compared to the control group (only TBH treated). There were no differences between pre-conditioned and per-conditioned groups. However, the ROS levels were more reduced in pre- and per-conditioned group compared to pre-conditioned or per-conditioned only groups. Furthermore, selective antagonists for the delta, kappa, or mu opioid receptor partially negated the hydromorphone effect.

CONCLUSION

This study demonstrated that hydromorphone can have additional protective effects on oxidative stress when pre- and per-conditioning is combined. Furthermore we proved that μ, δ, κ opioid receptors participate in protective mechanism of hydromorphone to glial cells.

Opioid receptors and cardioprotection - 'opioidergic conditioning' of the heart

Ischaemic heart disease (IHD) remains a major cause of morbidity/mortality globally, firmly established in Westernized or 'developed' countries and rising in prevalence in developing nations. Thus, cardioprotective therapies to limit myocardial damage with associated ischaemia-reperfusion (I-R), during infarction or surgical ischaemia, is a very important, although still elusive, clinical goal. The opioid receptor system, encompassing the δ (vas deferens), κ (ketocyclazocine) and μ (morphine) opioid receptors and their endogenous opioid ligands (endorphins, dynorphins, enkephalins), appears as a logical candidate for such exploitation. This regulatory system may orchestrate organism and organ responses to stress, induces mammalian hibernation and associated metabolic protection, triggers powerful adaptive stress resistance in response to ischaemia/hypoxia (preconditioning), and mediates cardiac benefit stemming from physical activity. In addition to direct myocardial actions, central opioid receptor signalling may also enhance the ability of the heart to withstand I-R injury. The δ- and κ-opioid receptors are strongly implicated in cardioprotection across models and species (including anti-infarct and anti-arrhythmic actions), with mixed evidence for μ opioid receptor-dependent protection in animal and human tissues. A small number of clinical trials have provided evidence of cardiac benefit from morphine or remifentanil in cardiopulmonary bypass or coronary angioplasty patients, although further trials of subtype-specific opioid receptor agonists are needed. The precise roles and utility of this GPCR family in healthy and diseased human myocardium, and in mediating central and peripheral survival responses, warrant further investigation, as do the putative negative influences of ageing, IHD co-morbidities, and relevant drugs on opioid receptor signalling and protective responses.

Opioid receptors and cardioprotection - 'opioidergic conditioning' of the heart

Ischaemic heart disease (IHD) remains a major cause of morbidity/mortality globally, firmly established in Westernized or 'developed' countries and rising in prevalence in developing nations. Thus, cardioprotective therapies to limit myocardial damage with associated ischaemia-reperfusion (I-R), during infarction or surgical ischaemia, is a very important, although still elusive, clinical goal. The opioid receptor system, encompassing the δ (vas deferens), κ (ketocyclazocine) and μ (morphine) opioid receptors and their endogenous opioid ligands (endorphins, dynorphins, enkephalins), appears as a logical candidate for such exploitation. This regulatory system may orchestrate organism and organ responses to stress, induces mammalian hibernation and associated metabolic protection, triggers powerful adaptive stress resistance in response to ischaemia/hypoxia (preconditioning), and mediates cardiac benefit stemming from physical activity. In addition to direct myocardial actions, central opioid receptor signalling may also enhance the ability of the heart to withstand I-R injury. The δ- and κ-opioid receptors are strongly implicated in cardioprotection across models and species (including anti-infarct and anti-arrhythmic actions), with mixed evidence for μ opioid receptor-dependent protection in animal and human tissues. A small number of clinical trials have provided evidence of cardiac benefit from morphine or remifentanil in cardiopulmonary bypass or coronary angioplasty patients, although further trials of subtype-specific opioid receptor agonists are needed. The precise roles and utility of this GPCR family in healthy and diseased human myocardium, and in mediating central and peripheral survival responses, warrant further investigation, as do the putative negative influences of ageing, IHD co-morbidities, and relevant drugs on opioid receptor signalling and protective responses.

Morphine inhibits migration of tumor-infiltrating leukocytes and suppresses angiogenesis associated with tumor growth in mice

Tumor cells secrete factors that stimulate the migration of peripheral blood leukocytes and enhance tumor progression by affecting angiogenesis. In these studies, we investigated the effect of morphine, a known immunosuppressant, on leukocyte migration and recruitment to conditioned media derived from long-term cultures of mouse Lewis lung carcinoma cells. Our results indicate that morphine treatment reduced the migration and recruitment of tumor-infiltrating leukocytes into Matrigel plugs and polyvinyl alcohol sponges containing conditioned media derived from long-term cultures of mouse Lewis lung carcinoma cells when compared with placebo. A reciprocal increase in peripheral blood leukocytes was observed at the time of plug or sponge removal in morphine-treated mice. Decreased angiogenesis was observed in conditioned media derived from long-term cultures of mouse Lewis lung carcinoma cells Matrigel plugs taken from morphine-treated wild-type mice when compared with placebo but was abolished in morphine-treated μ-opioid receptor knockout mice. In addition, in vitro studies using trans-well and electric cell substrate impedance sensing system studies reveal for the first time morphine's inhibitory effects on leukocyte migration and their ability to transmigrate across an activated endothelial monolayer. Taken together, these studies indicate that morphine treatment can potentially decrease leukocyte transendothelial migration and reduce angiogenesis associated with tumor growth. The use of morphine for cancer pain management may be beneficial through its effects on angiogenesis.

Opioids and immune modulation: more questions than answers

Opioid addicts are more likely to present with infections suggesting opioids are immune modulators. The potential sites/mechanism(s) for this modulation are controversial and on close inspection not well supported by the current literature. It has long been assumed that opioid-induced immune modulation occurs via a combination of direct actions on the immune cell itself, via the hypothalamic-pituitary-adrenal (HPA) axis, or both. Opioid receptors are classified as MOP (μ, mu), DOP (δ, delta), and KOP (κ, kappa)--classical naloxone sensitive receptors--or NOP (the receptor for nociceptin/orphanin FQ), which is naloxone insensitive. Opioids currently used in clinical practice predominantly target the MOP receptor. There do not appear to be classical opioid receptors present on immune cells. The evidence for HPA activation is also poor and shows some species dependence. Most opioids used clinically or as drugs of abuse do not target the NOP receptor. Other possible target sites for immune modulation include the sympathetic nervous system and central sites. We are currently unable to accurately define the cellular target for immune modulation and suggest further investigation is required. Based on the differences observed when comparing studies in laboratory animals and those performed in humans we suggest that further studies in the clinical setting are needed.

[D-Ala2,D-Leu5]-enkephalin (DADLE) and morphine-induced postconditioning by inhibition of mitochondrial permeability transition pore, in human myocardium

The aim of the study was to examine the cardioprotective effect of morphine and Delta 2 opioid D-Ala2-Leu5 enkephalin(DADLE) administered, at early reoxygenation, in isolated human myocardium exposed to hypoxia–reoxygenation. Then,we tested the involvement of mitochondrial permeability transition pore in morphine and DADLE-induced postconditioning.Human right atrial trabeculae were obtained during cardiac surgery (coronary artery bypass and aortic valve replacement).Isometrically contracting isolated human right atrial trabeculae were exposed to 30-min hypoxia and 60-min reoxygenation(control group). In treatment groups, morphine 0.5 mmol, DADLE 10 nmol, DADLE 50 nmol and DADLE 100 nmol were administered during the first 15 min of reoxygenation. In two additional groups, morphine and DADLE 100 nmol were administered in the presence of atractyloside 50 mmol, the mitochondrial permeability transition pore opener. The force of contraction at the end of 60-min reoxygenation period (FoC60 expressed as % of baseline) was compared (mean+standard deviation) between the groups by an analysis of variance. Morphine (FoC60: 81+9% of baseline), DADLE50 nmol (FoC60: 76+11% of baseline) and DADLE 100 nmol (FoC60: 81+4% of baseline) increased significantly (P,0.001) the FoC60 as compared with the control group (FoC60: 53+3% of baseline). DADLE 10 nmol did not modify the FoC60 (50+9% of baseline; P ¼ 0.60 versus control group). The enhanced recovery of FoC60 induced by morphine and DADLE 100 nmol were abolished in the presence of atractyloside (FoC60: respectively 57+6% and 44+7% of baseline;P, 0.001). In conclusion, the administration of morphine and DADLE, in early reoxygenation period, protected human myocardium, in vitro, against hypoxia–reoxygenation injury, at least in part, by the inhibition of mitochondrial permeability transition pore opening.

Endogenous opiates and behavior: 2011

This paper is the thirty-fourth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2011 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration (Section 16); and immunological responses (Section 17).

Influence of morphine on host immunity

Morphine is a widely used drug for analgesia and substance abuse. It has been accepted as a safe medication with great analgesic efficacy. Previous studies have reported that morphine is highly associated with the risk of immunosuppressive effects. Although the observed clinical effects suggest that morphine has the immunomodulatory capabilities, the mechanism of its action is still unclear. Here we review morphine on the bench to improve our understanding of the drug on the host immunity at the bedside. Studies of the effects of morphine on the innate and adaptive immune systems as well as immune responses are also discussed.

Morphine attenuates endothelial cell adhesion molecules induced by the supernatant of LPS-stimulated colon cancer cells

A large reservoir of bacterial lipopolysaccharide (LPS) is available in the colon and this could promote colon cancer metastasis by enhancing tumor cell adhesion, intravasation, and extravasation. Furthermore, adhesion molecules like ICAM-1, VCAM-1, and E-selectin play important roles in the adhesion of tumor cells to endothelium. This study was designed to determine whether morphine can attenuate the expressions of adhesion molecules up-regulated by the supernatant of LPS-stimulated HCT 116 colon cancer cells (LPS-Sup). In this study, we divided to three groups by cell-growth medium of human umbilical vascular endothelial cells (HUVECs): the control group was incubated in growth factor-free endothelial medium, the Sup group was incubated in the supernatant of HCT 116 cells (Sup), and the LPS-Sup group was incubated in LPS-Sup. To observe effect of morphine to the adhesion molecules expressions in the LPS-Sup group, we co-treated morphine with LPS or added it to LPS-Sup. Adhesion molecule expressions on HUVECs in all three groups were measured during incubation period. Consquentially, ICAM-1, VCAM-1, and E-selectin expressions on HUVECs were significantly lower when morphine was co-treated with LPS than not co-treated. Thus, we suggest that morphine affects the expressions of adhesion molecules primarily by attenuating LPS stimuli on tumor cells.