| 1. |
- Björklund, Emmelie, 1985-
(författare)
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The endocannabinoid system : a translational study from Achilles tendinosis to cyclooxygenase
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The endogenous cannabinoids anandamide (arachidonoyl ethanolamide, AEA) and 2-arachidonoyl glycerol (2-AG) exert their effect by activating cannabinoid receptors (CB). These receptors mediate a broad range of physiological functions such as beneficial effects in pain and inflammation, although little is known about the expression of CB receptors in human pain conditions. AEA and 2-AG are short- lived molecules due to their rapid cellular accumulation and metabolism. The enzymes primarily responsible for their degradation are fatty acid amide hydrolase (FAAH) for AEA and monoacylglycerol lipase (MGL) for 2-AG. Inhibition of endocannabinoid metabolism is a potential approach for drug development, and there is a need for the identification of novel compounds with inhibitory effects upon FAAH and MGL.In Paper I of this thesis, the expression of CB1 receptors in human Achilles tendon was examined. We found expression of CB1 receptors in tenocytes, blood vessel wall as well as in the perineurium of the nerve. A semi-quantitative analysis showed an increase of CB1 receptors in painful human Achilles tendinosis.In papers II and III, termination of AEA signalling was investigated via inhibition of FAAH. In Paper II, Flu-AM1, an analogue of flurbiprofen, was investigated. The compound inhibited both FAAH and the oxygenation of 2-AG by cyclooxygenase-2. In Paper III the antifungal compound ketoconazole was shown to inhibit the cellular uptake of AEA in HepG2, CaCo-2 and C6 cell lines in a manner consistent with inhibition of FAAH.The role of FAAH in gating the cellular accumulation of AEA was investigated in Paper IV. FAAH has been shown to control the concentration gradient of AEA across the plasmamembrane in RBL2H3 cells, whereas no such effect is seen in other FAAH-expressing cell lines. To determine whether this effect is assay dependent or due to intrinsic differences between the cell lines, we assayed four cell lines with different levels of FAAH expression using the same methodology. We found that the sensitivity of FAAH uptake inhibition was not dependent on the expression level of FAAH, suggesting that factors other than FAAH are important for uptake.Paper V is focused on the inhibition of MGL. Prior to this study no selective inhibitors of the enzyme had been described. Thus, we screened a number of compounds for their inhibitory effect on MGL. Troglitazone was found to be an inhibitor of MGL, although its potency was dependent upon the enzyme assay used.
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| 2. |
- Ghafouri, Nazdar, 1980-
(författare)
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Endocannabinoids and N-acylethanolamines in translational pain research : from monoacylglycerol lipase to muscle pain
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the early nineties cannabinoid receptors, the main target for Δ9-tetrahydrocannabinol (THC), the psychoactive component of marijuana were identified. Shortly after their endogenous ligands, N-arachidonoylethanolamine (anandamide, AEA) and 2-diacylglycerol (2-AG) were characterized. The enzymes primarily responsible for catalysing the degradation of AEA and 2-AG are fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MGL) respectively. AEA is a member of the N-acylethanolamine (NAE) class of lipids, which depending on the acyl chain length and number of double bonds can act as ligands for a variety of biological targets. Exogenous cannabinoids have long been reported to have analgesic effects, however the clinical usefulness of such substances is limited by their psychoactive effects. Inhibition of endocannabinoid degradation would mean enhancing the therapeutic effects without producing these unwanted side effects. In order to succeed in developing such compounds the pharmacology of the enzymes responsible for the degradation of endocannabinoids has to be thoroughly understood. When the preclinical part of this thesis was planned, FAAH had been well characterized whereas little was known as to the pharmacology of MGL. A series of compounds were tested in this first study aiming to find MGL-selective compounds. Although no compounds showed selectivity for MGL over FAAH, several interesting agents affecting both enzymes were identified.In order to increase the knowledge concerning which patient group would benefit from such treatment strategies it is important to investigate in which pain states the endocannabinoids/NAEs are altered. Thus the general aim of the clinical part of this thesis was to investigate the levels of endocannabinoids/NAEs in the interstitium of the trapezius muscle in women suffering from chronic neck/shoulder pain (CNSP) and chronic wide spread pain (CWP) and in healthy pain-free controls. Furthermore for the CNSP the effect of training, which is a commonly recommended treatment for these patients, on the levels of endocannabinoids/NAEs was also investigated. Microdialysis technique in the trapezius muscle was used for sampling and masspectrometry was used for analysing. Two NAEs,N-palmitoylethanolamine (PEA) and N-stearoylethanolamine (SEA), could be repeatedly measured. The levels of these two lipids were significantly higher in CNSP compared to CON. The result showed also that PEA and SEA mobilize differently in CWP compared to both CNSP and CON. Taken together the results presented in thesis represent an early characterization of the pharmacology of MGL and provides novel information on NAEs in chronic muscle pain.
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| 3. |
- Karlsson, Jessica, 1987-
(författare)
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Endocannabinoid metabolism : the impact of inflammatory factors and pharmacological inhibitors
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The endocannabinoid (eCB) system is an endogenous signaling system consisting of ligands (referred to as endocannabinoids, eCBs), receptors and metabolic enzymes. The eCB system is involved in homeostatic control of a variety of biological functions such as neuronal signaling, mood, appetite and pathological conditions such as pain, inflammation and tumour progression. The main eCBs N- arachidonoylethanolamine (AEA, anandamide) and 2-arachidonoylglycerol (2-AG) are synthesised upon stimuli when and where their action is demanded. The signaling is brief and the eCBs are quickly degraded. The enzyme primarily responsible for eCB degradation is fatty acid amide hydrolase (FAAH) for AEA and monoacylglycerol lipase (MAGL) for 2-AG. In addition, both substances are substrates for cyclooxygenase-2 (COX-2). COX-2 is upregulated in inflammation, pain and in several tumours including prostate cancers, but it is not known whether COX-2 contribute significantly to eCB metabolism under these conditions.Increasing endogenous levels of eCBs by inhibiting their degradation is exploited as a future therapy for pain conditions. One suggested therapeutic strategy is dual inhibition of enzymes FAAH and COX-2 to raise AEA levels. Paper I and II of this thesis investigates FAAH and COX inhibitory effects of: the major metabolites and enantiomers of derivatives (flu-AM1 and ibu-AM5) of the current clinically used NSAIDs ibuprofen and flurbiprofen. The metabolites 3 ́hydroxyibuprofen and 4 ́hydroxyflurbiprofen retained the FAAH and COX- inhibitory effects seen by the parent compounds although at lower potencies. Both enantiomers of flu-AM1 were equally potent as FAAH inhibitors and displayed a useful substrate selective COX-2 inhibition profile, favoring eCBs as substrates rather than arachidonic acid.Paper III explores the impact of COX-2 and the effect of (R)-flu-AM1 upon AEA levels and degradation in mouse leukemic macrophage RAW264.7 cells. Despite the high inhibitory potency in enzyme assays, neither (R)-flu-AM1 nor the combination of a FAAH inhibitor with flurbiprofen increased AEA levels in the intact cells to any great extent. This suggests that the eCB turnover in these cells is rather slow. Further, in paper IV, induction of COX-2 did not unmask an ability of this enzyme to “gate” the uptake of AEA analogous to that seen with FAAH.Paper IV and V focus upon the role of the eCB system in prostate cancer. The eCB system is altered in cancer and is linked to the progression and prognosis of prostate cancer. How and whereby this change occurs is unknown. This thesis explores the impact of the inflammatory factors TNFα, IL-6 and lactic acid induced low pH upon the mRNA levels of eCB related enzymes and the functional impact upon AEA degradation in human DU145 and rat AT-1 prostate cancer cells. TNFα treatment of DU145 and IL-6 and lactic acid induced low pH exposure of AT-1 changed the mRNA levels of 2-AG related enzymes leaving AEA rather unaffected other than for a substantial induction of COX-2 mRNA in DU145 cells. Thus, AEA homeostasis was not shifted in prostate cancer cell lines exposed to inflammatory factors. The results suggest that COX-2 does not gate the uptake of AEA and is a minor contributor to AEA degradation in intact cells.
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| 4. |
- Nilsson, Olov, 1975-
(författare)
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Cannabinoids as neuroprotective agents : a mechanistic study
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Glucose and oxygen supply to the brain is critical for its proper function and when it is restricted as during a stroke, neurons and glial cells quickly become necrotic leading to structural damage as well as functional impairment and even death. To date there are few effective therapies that inhibit the neurodegenerative process and improves the outcome for the affected individual. One possible target is the cannabinoid system. Cannabinoid receptor agonists reduce ischemic volume, endogenous cannabinoid levels are elevated during neurodegenerative insults and mice devoid of the central cannabinoid receptor are more seriously affected by experimental stroke than wild type mice. The cannabinoids are also ascribed anti-inflammatory properties and post ischemic inflammation has been proposed to contribute to the evolution of the ischemic damage. In this thesis mechanisms that can contribute to cannabinoid neuroprotection have been studied. In papers I and II the chick was used as a model species, since preparation of embryonic primary neuronal cultures from chick is relatively simple and time efficient compared to rodent primary cultures. Both adult and embryonic chick brain membranes contain functional CB1 receptors and in the cultures they are coupled to inhibition of cAMP production. In embryonic primary cultures, neurons were not protected from glutamate toxicity by preincubation with CB receptor agonists suggesting that postsynaptic cannabinoid mediated neuroprotection is not effective in this system. The effect of cannabinoid agonists on neutrophil chemotaxis and transmigration was investigated in paper III. The CB1/CB2 agonist WIN 55,212-2 inhibited TNF-α-induced transmigration across ECV304 cell monolayers. The effect of WIN 55,212-2 on this process which was mediated by a reduction of IL-8 release from the ECV304 cells rather than a direct effect upon the migratory response to IL-8 was not possible to abolish with CB1 or CB2 agonists suggesting a mechanism distinct from the cannabinoid receptors is operative. In paper IV the photothrombotic ring stroke model was evaluated to determine if it is suitable in intervention studies targeting the cannabinoid system. Three major endpoints were of interest, ischemic volume, neutrophil infiltration and CB1 receptor function. Consistent with previous studies the ischemic volume peaked at 48 hours after irradiation. Neutrophil infiltration was quantified using a myeloperoxidase activity assay. The assay revealed an increase in myeloperoxidase activity 48 hours after irradiation, albeit at a modest level. The function of the CB1 receptor was assessed by radioligand binding and there was no change in either total binding or functional G-protein coupling following photothrombosis. Taken together these results indicate that it is feasible to undertake cannabinoid intervention studies in this model.
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| 5. |
- Stensson, Niclas, 1974-
(författare)
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Endocannabinoids and Related Lipids in Chronic Pain : Analytical and Clinical Aspects
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In Europe, approximately one in five adults experience chronic pain, pain that lasts more than three months. Chronic pain is a significant problem not only for those people suffering from chronic pain but also for society. The prevalence of chronic pain is higher in women and lower socioeconomic groups. Although chronic pain often originates in a specific site, it may eventually spread to several sites, transforming into chronic widespread pain (CWP), a condition evident in about 10% of the adult population. Approximately 1.2-5.4% are classified with fibromyalgia (FM). In addition to CWP, common symptoms of FM include, stiffness, fatigue, sleep disturbances, and cognitive dysfunction and common co-morbidities include depression and anxiety. Although FM/CWP has been reported to alter both central and peripheral nociceptive mechanisms, no objective biomarkers have been found that correlate with CWP/FM and no standard examinations such as blood test, X-ray or computed tomography can provide support for a diagnosis. Because there are no objective biomarkers that correlate with the pathophysiological processes associated with CWP/FM, this debilitating disease is difficult to diagnose and ultimately treat. However, there are some promising therapeutic targets for chronic pain with inter alia analgesic, anti-inflammatory, and stress modulating properties: the endocannabinoids (ECs) arachidonoylethanolamide (AEA) and 2-arachidonoylglycerol (2-AG) and their related lipids oleoylethanolamide (OEA), palmitoylethanolamide (PEA), and stearoylethanolamide (SEA).This thesis investigates whether ECs and the related N-acylethanolamines (NAEs) can be used as potential biomarkers for CWP/FM. Specifically, the studies compared the peripheral and systemic levels of ECs and NAEs in 121 women with CWP/FM and in 137 healthy controls in two different cohorts. In addition, the correlation between lipid levels and common pain characteristics such as intensity, sensitivity, and duration were investigated. The EC and related lipid levels were measured using liquid chromatography in combination with tandem mass spectrometry. Multivariate data analysis was used for biomarker evaluation.Compared to the healthy controls, the CWP/FM patients had significantly higher concentrations of OEA, PEA, and SEA in muscle and plasma (p ≤ 0.05) and significantly higher 2-AG in plasma (p ≤ 0.01). These results may indicate that NAEs, are mobilized differently in painful muscles compared with pain free muscles. Moreover, increased systemic levels of NAEs and 2-AG in patients might be signs of ongoing low-grade inflammation inCWP/FM. These findings contribute to a better understanding of how peripheral and systemic factors maintain and activate chronic pain. Although the investigated lipids have statistically significant effects but biologically uncertain role in the clinical manifestations of CWP/FM. Thus plasma lipids are not a good biomarker for CWP/FM. Nevertheless, increased lipid levels indicate a metabolic asymmetry in CWP/FM, a finding that could serve as a basis for more research on pain management.
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| 6. |
- Thors, Lina, 1981-
(författare)
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The cellular processing of the endocannabinoid anandamide and its pharmacological manipulation
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Anandamide (arachidonoyl ethanolamide, AEA) and 2-arachidonoyl glycerol (2-AG) exert most of their actions by binding to cannabinoid receptors. The effects of the endocannabinoids are short-lived due to rapid cellular accumulation and metabolism, for AEA, primarily by the enzymes fatty acid amide hydrolase (FAAH). This has led to the hypothesis that by inhibition of the cellular processing of AEA, beneficial effects in conditions such as pain and inflammation can be enhanced. The overall aim of the present thesis has been to examine the mechanisms involved in the cellular processing of AEA and how they can be influenced pharmacologically by both synthetic natural compounds. Liposomes, artificial membranes, were used in paper I to study the membrane retention of AEA. The AEA retention mimicked the early properties of AEA accumulation, such as temperature-dependency and saturability. In paper II, FAAH was blocked by a selective inhibitor, URB597, and reduced the accumulation of AEA into RBL2H3 basophilic leukaemia cells by approximately half. Treating intact cells with the tyrosine kinase inhibitor genistein, an isoflavone found in soy plants and known to disrupt caveolae-related endocytosis, reduced the AEA accumulation by half, but in combination with URB597 no further decrease was seen. Further on, the effects of genistein upon uptake were secondary to inhibition of FAAH. The ability to inhibit the accumulation and metabolism of AEA was shared by several flavonoids (shown in paper III). In paper IV, the isoflavone biochanin A and URB597 had effects in vivo, in a model of persistent pain, effects decreased by the cannabinoid receptor 1 antagonist AM251. In paper VI, the cellular processing of the endocannabinoid metabolites following degradation was examined, a mechanism poorly understood. It was found that nitric oxide (NO) donors significantly increased the retention of tritium in cell membranes following incubation with either tritiated AEA or 2-AG. Further experiments revealed that the effect of NO donors mainly involves the arachidonate part of the molecules. Inhibition of FAAH completely reduced the effect of NO donors in cells with a large FAAH component, indicating that the effects were downstream of the enzyme. These results suggest that the cellular processing of endocannabinoids can be affected in a manner of different ways by pharmacological manipulation in vitro and that naturally occurring flavonoid compounds can interact with the endocannabinoid system.
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| 7. |
- Ekegren, Titti, 1971-
(författare)
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Transmethylation, Polyamines and Apoptosis in Amyotrophic Lateral Sclerosis
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Amyotrophic lateral sclerosis (ALS) is a relentlessly progressive disorder characterized by degeneration of motor neurons in the cortex, brainstem and spinal cord. The patients usually die within 3-5 years after onset. The full etiology of ALS is unknown and many hypotheses have been proposed to explain the neurodegeneration. However, basic mechanisms of cellular function such as transmethylation and polyamine metabolism have not been extensively studied in ALS. Transmethylation reactions are very important in the synthesis of substrates such as proteins, neurotransmitters, DNA and RNA. The polyamines, putrescine, spermidine and spermine, are involved in essential functions such as cellular growth, proliferation and differentiation.An initial study in this thesis concerned the process of neuronal death (apoptosis) in ALS spinal cord. The results showed increased levels of an apoptosis-stimulating protein and increased levels of DNA fragmentation indicative of an apoptotic process in the tissue. A comparative study of MAT-enzyme activity in spinal cord from different mammalian species was undertaken to provide a background for future studies on transmethylation and neurodegeneration. Transmethylation reactions were found altered in erythrocytes from males with ALS but not in spinal cord from ALS patients as compared to controls. An adaptation of previously described polyamine assays was made for the study of polyamines in ALS spinal cord. The method was validated and applied for polyamine analysis in human materials of different characteristics. Determination of polyamines in control and ALS spinal cords showed no major differences. However, in female ALS patients, significantly increased spermidine and spermine levels were observed in ventral horn regions. These gender-related alterations in transmethylation and polyamine metabolism are of interest since there is a male preponderance for the disease.The lack of major differences in polyamine levels between ALS and control spinal cord suggests a maintained regulation of polyamines at the end stage of this neurodegenerative disease.
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| 8. |
- Rankin, Linda, 1987-
(författare)
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Chronic pain : from the study of student attitudes and preferences to the in vitro investigation of a novel treatment strategy
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Chronic pain will affect one in five adults during their lifetime, and it exerts a heavy burden on society with major physiological, psychological, social, and economic impacts. The current chronic pain curriculum taught to medical students in most settings is fragmented, inconsistent and inadequate and a vast majority of general practitioners considered their undergraduate training in chronic pain incomplete. Attitudes and beliefs amongst health care personnel are important and have shown to have impact on clinical management. There is currently a knowledge gap that needs to be addressed in this matter. In this thesis, through an online survey, the attitudes and beliefs of medical students in Sweden and Australia were surveyed. Additionally, we explored which factors influence chronic pain management amongst medical students in Sweden and Australia and Swedish general practitioners. We found that Swedish final year students have a more positive attitude towards chronic pain patients compared to Australian students. Both student cohorts perceived chronic pain management education in need of improvement. Furthermore, we found that the relative importance of factors that influence treatment decisions are formed early during undergraduate training, which further underlines the importance of improving pain curricula during undergraduate medical education in order to give the emerging workforce appropriate tools to manage chronic pain.Management of chronic pain urgently requires novel, well-tolerated pharmacological treatment strategies. Palmitoylethanolamide (PEA) is a potential candidate for managing chronic pain. Its analgesic and anti-inflammatory effects have been observed in a range of experimental animal models and clinical trials. However, questions remain as to how PEA exerts its effects and how levels of PEA and its congeners are changed in states of pain and inflammatory disorders in humans. Treatment with PEA decreases cyclooxygenase 2 (COX-2) activity in animal models, but we found that PEA did not have direct effects upon the kinetic properties of COX-2 in a cell free system. However, COX-2 derived eicosanoid levels were reduced by PEA in lipopolysaccharide and interferon-g-stimulated RAW 264.7 cells. With respect to changes in PEA levels in a chronic inflammatory disorder, we investigated PEA levels, in addition to its synthesizing and hydrolysing enzymes in biopsies from patients with oral lichen planus (OLP). We found that the ratio of prostaglandins to PEA was increased in the OLP biopsy samples. Furthermore, PTGS2 mRNA levels (coding for COX-2) were increased in OLP-patients compared to controls relative to NAPEPLD mRNA levels (coding for a key enzyme in the synthesis of PEA). These results suggest that there is a relative deficit of PEA in OLP, raising the possibility that PEA might be useful for the treatment of this disorder.
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