Insights in opiates toxicity: impairment of human vascular mesenchymal stromal cells.

The most common pulmonary findings in opiate-related fatalities are congestion and oedema, as well as acute and/or chronic alveolar haemorrhage, the cause of which is thought to be a damage to the capillary endothelium related to ischemia. Human vascular mesenchymal stromal cells (vMSCs) play a fundamental role in tissue regeneration and repair after endothelial cell injury, and they express opioid receptors. The aim of this study was to assess the effect of in vitro morphine exposure on the physiological activity and maintenance of human vMSCs. vMSCs were obtained from abdominal aorta fragments collected during surgery repair and were exposed to incremental doses (0.1 mM, 0.4 mM, 0.8 mM and 1 mM) of morphine sulphate for 7 days. The effect was investigated through cell viability assessment, proliferation assay, reactive oxygen species (ROS) detection assay, senescence-associated ß-galactosidase assay, senescent-related markers (p21WAF1/CIP1 and p16INK4) and the apoptosis-related marker caspase 3. Moreover, an ultrastructural analysis by transmission electron microscopy and in vitro vascular differentiation were evaluated. Results showed a decrease of the cellular metabolic activity, a pro-oxidant and pro-senescence effect, an increase in intracellular ROS and the activation of the apoptosis signalling, as well as ultrastructural modifications and impairment of vascular differentiation after morphine treatment of vMSC. Although confirmation studies are required on real fatal opiate intoxications, the approach based on morphological and immunofluorescence methodologies may have a high potential also as a useful tool or as a complementary method in forensic pathology. The application of these techniques in the future may lead to the identification of new markers and morphological parameters useful as complementary investigations for drug-related deaths.

Reducing harm through the development of good preparation practices for the injection of slow release morphine sulphate capsules.

BACKGROUND: It is not always easy to advise people who inject drugs (PWID) on how to prepare their drugs in a way that is associated with reduced harm. This is particularly true for pharmaceutical drugs that are not meant to be injected. Our objective was to find "good preparation practices" for slow release morphine sulphate capsules, namely preparation methods that reduce harm, that are evidence-based and acceptable to PWID. METHODS: In the laboratory, morphine sulphate capsules were prepared using both a cold and lukewarm preparation technique, two contact and stirring durations (1 min and 20 s) and 4 different filters (cotton filter, Sterifilt, Sterifilt+ and a wheel filter). The following outcomes were compared: particle reduction and morphine content in the filtrate, as well as filtration ease and time. RESULTS: The lukewarm method and a stirring and contact time of 1 min were associated with a considerably higher morphine yield than both the cold method and the stirring time of only 20 s. Moreover, the suspension obtained was easy to filter using membrane filters. Particle reduction was important with all three membrane filters tested. Using the lukewarm method, morphine recovery was 86% for the wheel filter, 89% for the Sterifilt and 99% for the Sterifilt+. CONCLUSIONS: The provision of a method that is easy to use, reduces harms associated to the injection of insoluble particles and recovers virtually all the active drug has a large chance to be adopted by people who use drugs. This type of "best practices" can be provided by drug workers and by people who use drugs to actively promote harm reduction.

Cardamonin attenuates hyperalgesia and allodynia in a mouse model of chronic constriction injury-induced neuropathic pain: Possible involvement of the opioid system.

Neuropathic pain arises from the injury of nervous system. The condition is extremely difficult to be treated due to the ineffectiveness and presence of various adverse effects of the currently available drugs. In the present study, we investigated the antiallodynic and antihyperlagesic properties of cardamonin, a naturally occurring chalcone in chronic constriction injury (CCI)-induced neuropathic pain mice model. Our findings showed that single and repeated dose of intra-peritoneal administration of cardamonin (3, 10, 30mg/kg) significantly inhibited (P<0.001) the chronic constriction injury-induced neuropathic pain using the Hargreaves plantar test, Randall-Selitto analgesiometer test, dynamic plantar anesthesiometer test and the cold plate test in comparison with the positive control drug used (amitriptyline hydrochloride, 20mg/kg, i.p.). Pre-treatment with naloxone hydrochloride (1mg/kg, i.p.) and naloxone methiodide (1mg/kg, s.c) significantly reversed the antiallodynic and antihyperalgesic effects of cardamonin in dynamic plantar anesthesiometer test and Hargreaves plantar test, respectively. In conclusion, the current findings demonstrated novel antiallodynic and antihyperalgesic effects of cardamonin through the activation of the opioidergic system both peripherally and centrally and may prove to be a potent lead compound for the development of neuropathic pain drugs in the future.

Influence of pH and temperature on ziconotide stability in intrathecal analgesic admixtures in implantable pumps and syringes.

PURPOSE: The aim of our study was to investigate the influence of pH and temperature on the stability of ziconotide in analgesic admixtures containing morphine and ropivacaine. METHODS: All admixtures were combined using a wide range of concentrations, in implantable pumps and syringes, using temperatures from 4°C to 37°C. Quantification was made thanks to a specific chromatographic technique. pH has also been measured throughout the study. RESULTS: Admixtures confirm excellent stability for morphine and ropivacaine. Concerning ziconotide, an acid hydrolysis has been observed, reducing the time of use of our admixtures in a significant way, but producing non-toxic degradation products. The degradation was linear in all conditions. Inside the implantable pumps at body temperature turned out to be the best conditions for lower protein breakdown. Finally the degradation process showed a high correlation with the pH and the morphine concentration with a median loss of concentration delay due to degradation of 3.5 days [3; 5] when pH<4.5 and 13 days [13; 24] when pH ≥ 4.5. CONCLUSION: Our admixtures showed different stability depending on the drug concentrations, pH and temperature. The great majority of mixtures in real life in our institution have stability highly compatible with our practice and with the delay between two pump refilling.

Contrasting cardiovascular properties of the µ-opioid agonists morphine and methadone in the rat.

Morphine and methadone share the property of µ-opioid receptor agonism yet have markedly different cardiovascular actions suggesting additional properties are at play. We investigated the i.v. dose-response relationships of the opioids on cardiovascular metameters in anaesthetised rats in the absence or presence of H1- and H2-receptor antagonism and the µ-opioid antagonist naloxone. In vitro tissue assays were employed to define more clearly cardiac and vascular mechanisms of action. Morphine (9, 30, 90mg/kg i.v.) decreased heart rate (HR) and mean arterial pressure (MAP) - responses that were blocked by naloxone pretreatment (10mg/kg i.v.). In contrast, methadone (3, 10, 30mg/kg i.v.) caused dramatic short-lived (1-3min) bradycardia, hypotension and lengthening of the QT interval before stabilising 5min after i.v. dosing. Only the steady-state responses of HR and MAP were blocked by naloxone. Mepyramine (10mg/kg i.v.) and cimetidine (100mg/kg i.v.) also blocked the naloxone-sensitive components. In isolated small mesenteric arteries precontracted by K(+) 62mM or endothelin-1, methadone (1-30µM) relaxed vessels while morphine (1-100µM) had no effect. Pretreatment with naloxone (10µM), indomethacin (30µM) or nitro-l-arginine (100µM) did not affect the relaxation to methadone. In rat isolated left atria, morphine and methadone inhibited inotropic responses at high concentrations (100µM). In rat papillary muscle and right atria, methadone was more than 30 times more potent at lengthening the refractory period and slowing the atrial rate than morphine. We conclude that methadone is a potent vasodilator agent, possibly through blocking L-type calcium channels.

Is opiate action in cough due to sedation?

OBJECTIVES: Opiates have been used for cough suppression for centuries. It is unclear whether this antitussive action is due to their known sedative effects. We aimed to assess correlation between cough suppression and opiate usage. METHODS: We performed a post hoc analysis of two published trials with three opioids. In study one, patients with chronic cough were treated with 4 weeks of modified release morphine sulphate (5 mg twice daily) or placebo in a double-blinded placebo-controlled fashion. Cough suppression was assessed subjectively by the Leicester Cough Questionnaire and objectively by citric acid aerosol (CAA) induced cough challenge. In study 2, normal volunteers were given single doses of placebo, codeine 30 mg or dextromethorphan 50 mg and cough suppression assessed using the CAA-induced cough challenge. Sedation was contemporaneously assessed by direct questioning. RESULTS: There were 14 episodes of patient-reported sedation; 2 with modified release morphine sulphate, 9 with codeine and 3 with dextromethorphan. There was no correlation between change in the Leicester Cough Questionnaire or the CAA-induced cough challenge and reported sedation. CONCLUSION: This observational study suggests that sedation is unlikely to underlie the antitussive properties of these opioids. Eliciting the mechanism of these medications in cough may be a target for future tailored drug development.