8 resultados para ANALGESICS, Opioids
em AMS Tesi di Dottorato - Alm@DL - Università di Bologna
Resumo:
In chronic pain, opioids represent the gold standard analgesics, but their use is hampered by the development of several side effects, as development of analgesic tolerance and opioid-induced hyperalgesia. Evidence showed that many molecular mechanisms (changes in opioid receptors, neurotransmitter release, and glia/microglia activation) are involved in their appearance, as well as in chronic pain. Recently, a crucial role has been proposed for oxidative stress and proteasome in chronic pain and in treatment-related side effects. To better elucidate these aspects, the aim of this PhD thesis was to investigate the effects of opioids on cell oxidative stress, antioxidant enzymatic machinery and proteasome expression and activity in vitro. Also, the involvement of proteasome in the development of chronic pain conditions was investigated utilizing an experimental model of oxaliplatin-induced neuropathy (OXAIN), in vivo. Data showed that morphine, fentanyl, buprenorphine and tapentadol alter differently ROS production. The ROS increasing effect of morphine is not shared by the other opioids, suggesting that the different pharmacological profile could influence this parameter. Moreover, these drugs produced different alterations of β2trypsin-like and β5chymotrypsin-like activities. In fact, while morphine and fentanyl increased the proteolytic activity after prolonged exposure, a different picture was observed for buprenorphine and tapentadol, suggesting that the level of MOR agonism could be strongly related with proteasome activation. In vivo studies revealed that rats treated with oxaliplatin showed a significant increase in β5, in the thalamus (TH) and somatosensory cortex (SSCx). Moreover, a selective up-regulation of β5 and LMP7 subunit gene expression was assessed in the SSCx. Furthermore, our study revealed that oprozomib, a selective β5 inhibitor normalized the spinal prodynorphin gene expression upregulation induced by oxaliplatin, and reverted mechanical/thermal allodynia and mechanical hyperalgesia in oxaliplatin-treated rats. These results underline the role of proteasome in the OXAIN and suggest new pharmacological targets to counteract it.
Resumo:
In the contest of a modern green chemistry approach, we firstly tried to substituent the classic peptide synthesis approach with the use of N-carboxyanhydrides in the presence of Hydroxyapatite, a high biocompatible inorganic base. Despite the great results, further developments are necessary for a daily use in laboratory and for our research, we decided to proceed with solid phase or liquid phase synthesis. In the first chapter, the treatment of pain with the use of opioids is introduced. The abuse and misuse of these kind of potent analgesics, led to the necessity of developing new drugs with less side effects. Starting from a previous study, where the introduction of a lactam-like structure in the place of the proline of Endomorphine1, switched the selectivity from MOR to KOR, we designed and synthetized three different libraries by placing a different trans inducer element to gain the desired selectivity and activity forcing the structure to adopt a linear rather than folded position. In the second chapter, we focused on lactate dehydrogenase, an enzyme overexpressed when the cells in hypoxia conditions, like in a tumour mass, need to produce energy through the transformation of pyruvate into lactate. We synthetized different cyclic peptidomimetics, designed to be inhibitors, as powerful tool to contrast cancer cells growing. Biological assays produced satisfactory preliminary results, but further studies are necessary for a definitive output. Finally in the last chapter, the cancer treatment problem is also approached through the design of nanoparticles, able to deliver drugs with efficacy and selectivity. We firstly synthetized silica core nanoparticles, built with toxic peptide sequences conjugated through click chemistry with Pluronic acid and then, in collaboration with Miriam Royo’s research group, we synthetized multivalent platforms for used drugs for the treatment of advanced colorectal cancer.
Resumo:
The organization of the nervous and immune systems is characterized by obvious differences and striking parallels. Both systems need to relay information across very short and very long distances. The nervous system communicates over both long and short ranges primarily by means of more or less hardwired intercellular connections, consisting of axons, dendrites, and synapses. Longrange communication in the immune system occurs mainly via the ordered and guided migration of immune cells and systemically acting soluble factors such as antibodies, cytokines, and chemokines. Its short-range communication either is mediated by locally acting soluble factors or transpires during direct cell–cell contact across specialized areas called “immunological synapses” (Kirschensteiner et al., 2003). These parallels in intercellular communication are complemented by a complex array of factors that induce cell growth and differentiation: these factors in the immune system are called cytokines; in the nervous system, they are called neurotrophic factors. Neither the cytokines nor the neurotrophic factors appear to be completely exclusive to either system (Neumann et al., 2002). In particular, mounting evidence indicates that some of the most potent members of the neurotrophin family, for example, nerve growth factor (NGF) and brainderived neurotrophic factor (BDNF), act on or are produced by immune cells (Kerschensteiner et al., 1999) There are, however, other neurotrophic factors, for example the insulin-like growth factor-1 (IGF-1), that can behave similarly (Kermer et al., 2000). These factors may allow the two systems to “cross-talk” and eventually may provide a molecular explanation for the reports that inflammation after central nervous system (CNS) injury has beneficial effects (Moalem et al., 1999). In order to shed some more light on such a cross-talk, therefore, transcription factors modulating mu-opioid receptor (MOPr) expression in neurons and immune cells are here investigated. More precisely, I focused my attention on IGF-I modulation of MOPr in neurons and T-cell receptor induction of MOPr expression in T-lymphocytes. Three different opioid receptors [mu (MOPr), delta (DOPr), and kappa (KOPr)] belonging to the G-protein coupled receptor super-family have been cloned. They are activated by structurallyrelated exogenous opioids or endogenous opioid peptides, and contribute to the regulation of several functions including pain transmission, respiration, cardiac and gastrointestinal functions, and immune response (Zollner and Stein 2007). MOPr is expressed mainly in the central nervous system where it regulates morphine-induced analgesia, tolerance and dependence (Mayer and Hollt 2006). Recently, induction of MOPr expression in different immune cells induced by cytokines has been reported (Kraus et al., 2001; Kraus et al., 2003). The human mu-opioid receptor gene (OPRM1) promoter is of the TATA-less type and has clusters of potential binding sites for different transcription factors (Law et al. 2004). Several studies, primarily focused on the upstream region of the OPRM1 promoter, have investigated transcriptional regulation of MOPr expression. Presently, however, it is still not completely clear how positive and negative transcription regulators cooperatively coordinate cellor tissue-specific transcription of the OPRM1 gene, and how specific growth factors influence its expression. IGF-I and its receptors are widely distributed throughout the nervous system during development, and their involvement in neurogenesis has been extensively investigated (Arsenijevic et al. 1998; van Golen and Feldman 2000). As previously mentioned, such neurotrophic factors can be also produced and/or act on immune cells (Kerschenseteiner et al., 2003). Most of the physiologic effects of IGF-I are mediated by the type I IGF surface receptor which, after ligand binding-induced autophosphorylation, associates with specific adaptor proteins and activates different second messengers (Bondy and Cheng 2004). These include: phosphatidylinositol 3-kinase, mitogen-activated protein kinase (Vincent and Feldman 2002; Di Toro et al. 2005) and members of the Janus kinase (JAK)/STAT3 signalling pathway (Zong et al. 2000; Yadav et al. 2005). REST plays a complex role in neuronal cells by differentially repressing target gene expression (Lunyak et al. 2004; Coulson 2005; Ballas and Mandel 2005). REST expression decreases during neurogenesis, but has been detected in the adult rat brain (Palm et al. 1998) and is up-regulated in response to global ischemia (Calderone et al. 2003) and induction of epilepsy (Spencer et al. 2006). Thus, the REST concentration seems to influence its function and the expression of neuronal genes, and may have different effects in embryonic and differentiated neurons (Su et al. 2004; Sun et al. 2005). In a previous study, REST was elevated during the early stages of neural induction by IGF-I in neuroblastoma cells. REST may contribute to the down-regulation of genes not yet required by the differentiation program, but its expression decreases after five days of treatment to allow for the acquisition of neural phenotypes. Di Toro et al. proposed a model in which the extent of neurite outgrowth in differentiating neuroblastoma cells was affected by the disappearance of REST (Di Toro et al. 2005). The human mu-opioid receptor gene (OPRM1) promoter contains a DNA sequence binding the repressor element 1 silencing transcription factor (REST) that is implicated in transcriptional repression. Therefore, in the fist part of this thesis, I investigated whether insulin-like growth factor I (IGF-I), which affects various aspects of neuronal induction and maturation, regulates OPRM1 transcription in neuronal cells in the context of the potential influence of REST. A series of OPRM1-luciferase promoter/reporter constructs were transfected into two neuronal cell models, neuroblastoma-derived SH-SY5Y cells and PC12 cells. In the former, endogenous levels of human mu-opioid receptor (hMOPr) mRNA were evaluated by real-time PCR. IGF-I upregulated OPRM1 transcription in: PC12 cells lacking REST, in SH-SY5Y cells transfected with constructs deficient in the REST DNA binding element, or when REST was down-regulated in retinoic acid-differentiated cells. IGF-I activates the signal transducer and activator of transcription-3 (STAT3) signaling pathway and this transcription factor, binding to the STAT1/3 DNA element located in the promoter, increases OPRM1 transcription. T-cell receptor (TCR) recognizes peptide antigens displayed in the context of the major histocompatibility complex (MHC) and gives rise to a potent as well as branched intracellular signalling that convert naïve T-cells in mature effectors, thus significantly contributing to the genesis of a specific immune response. In the second part of my work I exposed wild type Jurkat CD4+ T-cells to a mixture of CD3 and CD28 antigens in order to fully activate TCR and study whether its signalling influence OPRM1 expression. Results were that TCR engagement determined a significant induction of OPRM1 expression through the activation of transcription factors AP-1, NF-kB and NFAT. Eventually, I investigated MOPr turnover once it has been expressed on T-cells outer membrane. It turned out that DAMGO induced MOPr internalisation and recycling, whereas morphine did not. Overall, from the data collected in this thesis we can conclude that that a reduction in REST is a critical switch enabling IGF-I to up-regulate human MOPr, helping these findings clarify how human MOPr expression is regulated in neuronal cells, and that TCR engagement up-regulates OPRM1 transcription in T-cells. My results that neurotrophic factors a and TCR engagement, as well as it is reported for cytokines, seem to up-regulate OPRM1 in both neurons and immune cells suggest an important role for MOPr as a molecular bridge between neurons and immune cells; therefore, MOPr could play a key role in the cross-talk between immune system and nervous system and in particular in the balance between pro-inflammatory and pro-nociceptive stimuli and analgesic and neuroprotective effects.
Resumo:
Drug abuse is a major global problem which has a strong impact not only on the single individual but also on the entire society. Among the different strategies that can be used to address this issue an important role is played by identification of abusers and proper medical treatment. This kind of therapy should be carefully monitored in order to discourage improper use of the medication and to tailor the dose according to the specific needs of the patient. Hence, reliable analytical methods are needed to reveal drug intake and to support physicians in the pharmacological management of drug dependence. In the present Ph.D. thesis original analytical methods for the determination of drugs with a potential for abuse and of substances used in the pharmacological treatment of drug addiction are presented. In particular, the work has been focused on the analysis of ketamine, naloxone and long-acting opioids (buprenorphine and methadone), oxycodone, disulfiram and bupropion in human plasma and in dried blood spots. The developed methods are based on the use of high performance liquid chromatography (HPLC) coupled to various kinds of detectors (mass spectrometer, coulometric detector, diode array detector). For biological sample pre-treatment different techniques have been exploited, namely solid phase extraction and microextraction by packed sorbent. All the presented methods have been validated according to official guidelines with good results and some of these have been successfully applied to the therapeutic drug monitoring of patients under treatment for drug abuse.
Resumo:
Con il termine IPC (precondizionamento ischemico) si indica un fenomeno per il quale, esponendo il cuore a brevi cicli di ischemie subletali prima di un danno ischemico prolungato, si conferisce una profonda resistenza all’infarto, una delle principali cause di invalidità e mortalità a livello mondiale. Studi recenti hanno suggerito che l’IPC sia in grado di migliorare la sopravvivenza, la mobilizzazione e l’integrazione di cellule staminali in aree ischemiche e che possa fornire una nuova strategia per potenziare l’efficacia della terapia cellulare cardiaca, un’area della ricerca in continuo sviluppo. L’IPC è difficilmente trasferibile nella pratica clinica ma, da anni, è ben documentato che gli oppioidi e i loro recettori hanno un ruolo cardioprotettivo e che attivano le vie di segnale coinvolte nell’IPC: sono quindi candidati ideali per una possibile terapia farmacologica alternativa all’IPC. Il trattamento di cardiomiociti con gli agonisti dei recettori oppioidi Dinorfina B, DADLE e Met-Encefalina potrebbe proteggere, quindi, le cellule dall’apoptosi causata da un ambiente ischemico ma potrebbe anche indurle a produrre fattori che richiamino elementi staminali. Per testare quest’ipotesi è stato messo a punto un modello di “microambiente ischemico” in vitro sui cardiomioblasti di ratto H9c2 ed è stato dimostrato che precondizionando le cellule in modo “continuativo” (ventiquattro ore di precondizionamento con oppioidi e successivamente ventiquattro ore di induzione del danno, continuando a somministrare i peptidi oppioidi) con Dinorfina B e DADLE si verifica una protezione diretta dall’apoptosi. Successivamente, saggi di migrazione e adesione hanno mostrato che DADLE agisce sulle H9c2 “ischemiche” spronandole a creare un microambiente capace di attirare cellule staminali mesenchimali umane (FMhMSC) e di potenziare le capacità adesive delle FMhMSC. I dati ottenuti suggeriscono, inoltre, che la capacità del microambiente ischemico trattato con DADLE di attirare le cellule staminali possa essere imputabile alla maggiore espressione di chemochine da parte delle H9c2.
Resumo:
Cancer is a disease that has plagued scientists for decades, and how to treat cancer and its complications are inevitable topics in current scientific research. Cancer pain is a major factor that reduces the quality of life of patients. Therefore, the development of analgesic agents with minimal adverse side effects, especially with low addiction, has attracted more and more attention. Among them, opioid analgesics are widely used to alleviate cancer pain and improve the quality of life of patients with advanced cancer, such as in the palliative therapy. Although peptide drugs are efficient, selective and safe, they have several unignorable disadvantages such as poor biological stability, rapid excretion, difficulty in penetrate blood brain barrier. In order to solve these problems, peptidomimetics were developed by introducing unnatural/modified amino acids, decorated peptide backbone, conformational restrictions and secondary structure mimics in peptide sequence. Compared with peptides, peptidomimetics have improved biological stability, increased bioavailability, high affinity and selectivity for receptor binding, and decreased adverse side effects. As the second part of this thesis, I explored the opportunity to design peptide-functionalized responsive biomaterials for the detection of cancer cell and the selective delivery of cytotoxic drugs. The conjugation of peptides with biomaterials enhanced the stability of the loaded drugs, improved targeted delivery, decreased side effects, and increased bioavailability. The precise and controllable drug delivery platform has profound application prospects in cancer treatment. Grafting specific peptides sequence on the surface of biomaterials can satisfy different drug delivery demands according to the characteristics of both peptides and biomaterials. For example, the introduction of tumor-targeting peptides can guide biomaterials into tumor lesions, and blood-brain barrier (BBB) shuttle peptides can lead biomaterials to penetrate the BBB, etc.
Resumo:
Introduction. The term New Psychoactive Substances (NPS) encompasses a broad category of drugs which have become available on the market in recent years and whose illicit use for recreational purposes has recently exploded. The analysis of NPS usually requires mass spectrometry based techniques. The aim of our study was to define the preva-lence of NPS consumption in patients with a history of drug addiction followed by Public Services for Pathological Addictions, with the purpose of highlighting the effective presence of NPS within the area of Bologna and evaluating their association with classical drugs of abuse (DOA). Materials and methods. Sustained by literature, a multi-analyte UHPLC-MS/MS method for the identification of 127 NPS (phenethylamines, arylcyclohexylamines, synthetic opioids, tryptamines, synthetic cannabinoids, synthetic cathinones, designer benzodiazepines) and 15 classic drugs of abuse (DOA) in hair samples was developed and validated according to International Guidelines [112]. Samples pretreatment consisted of washing steps and overnight incubation at 45°C in an acid mixture of methanol and water. After cooling, supernatant were injected into the chromatographic system coupled with a tandem mass spectrometry detector. Results. Successful validation was achieved for almost all of the compounds. The method met all the required technical parameters. LOQ was set from 4 to 80 pg/mg The developed method was applied to 107 cases (85 males and 22 females) of clinical interest. Out of 85 hair samples resulting positive to classical drugs of abuse, NPS were found in twelve (8 male and 4 female). Conclusion. The present methodology represents an easy, low cost, wide-panel method for the de-tection of 127 NPS and 15 DOA in hair samples. Such multi-analyte methods facilitates the study of the prevalence of drugs abused that will enable the competent control authorities to obtain evi-dence-based reports regarding the critical spread of the threat represented by NPS.
Resumo:
ABSTRACT Background:Strong opioids are the treatment of choice for moderate to severe cancer-related pain. Fentanyl is a synthetic opioid with high affinity for the μ-opioid receptor and is 75–100 times more potent than morphine. Fentanyl is metabolised rapidly, particularly in the liver and only 10% is excreted as intact substance. The use of CYP3A4 inhibitors and inducers, impaired liver function, and heating of the patch potentially influence fentanyl pharmacokinetics in a clinically relevant way. The influence of BMI and gender on fentanyl pharmacokinetics is questionable. Pharmacogenetic, may influence fentanyl pharmacokinetic and other factors have been studied but did not show significant and clinically relevant effects on fentanyl pharmacokinetic. Method: This is a biological interventional prospective, single-center study in 49 patients with solid or haematological neoplasm treated with transdermal fentanyl undergoing 5-step pharmacokinetic and pharmacogenetic withdrawals from administration of the fentanyl patch. Objective:to evaluate the pharmacokinetic and pharmacogenetic of transdermal fentanyl in relation to the patient's clinical response on pain Results: Sex was the only parameter with evidence of different distribution between responders and non-responders , showing a major chance for male to be responders than females. We found some correlation with pharmacokinetic parameters and sex, regarding adverse events and NRS correlation with BPI. NAT2 and UGT2B7 polymorphisms are associated with AUC and Cmax kinetics parameters, NAT2 and CYP4F2 showed some evidence of association with the fentanyl dosage and CYP2B6 polymorphism seemed to be correlate with side effects. Conclusion: Small sample size of study population make difficult do find some significant correlation between pharmacogenetic, pharmacokinetic and clinical response. Larger studies are needed to increase knowledge about response to opioid treatment in cancer patients to better individualized pain treatment.