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ItemOpen Access
Long-Term Opioid Prescribing among Patients Living with Metastatic Cancer as a Chronic Disease
(2024-10-28) Harsanyi, Hannah; Cuthbert, Colleen; Yang, Lin; Lau, Jenny; Cheung, Winson Y.
Patients living with metastatic cancer often experience pain which requires involvement of palliative care and symptom management teams. Opioids are a commonly used tool for the treatment of this cancer-related pain. While opioids serve an important purpose in symptom management and end-of-life care, harms related to their use are increasingly recognized as having a significant impact on patients with cancer. This changing perception has resulted from a growing body of literature investigating opioid-related harms, such as long-term prescribing, opioid-related healthcare utilization, and nonmedical use within cancer populations. However, many of these studies exclude patients with metastatic disease, and very few specifically investigate this population. The work reported in this thesis aims to address this knowledge gap by reviewing perceptions of opioid use among patients with metastatic disease, investigating the incidence of opioid-related hospitalizations and emergency department visits among recipients of long-term opioid prescribing, and determining the contribution of nonmedical opioid use to these encounters. Based on a review of previously published literature, stigmatization of opioid use was identified as a significant barrier to effective cancer pain management. Patients reported fears of addiction, tolerance, and side-effects which led to opioid-restricting behaviours. Despite these reported concerns, a large proportion of patients in Alberta received long-term opioid prescribing, with 23% of opioid-naïve patients with chronic metastatic disease being affected. Among these patients, the incidence of opioid-related healthcare encounters was higher than that reported in other cancer populations and was significantly associated with higher dosage and concurrent prescribing of psychoactive medications. Increased implementation of harm-reduction measures may be useful to mitigate this risk. From reviewing medical records of patients who experienced opioid-related healthcare encounters, nonmedical opioid use was identified as a possible contributing factor for 35% of patients. However, a majority of encounters were not primarily attributable to nonmedical opioid use and many patients experienced poorly controlled pain and displayed possible manifestations of opioid stigma. While risk assessment for nonmedical opioid use is important for patients receiving long-term opioid prescribing, it should be conducted in a non-stigmatizing manner which encourages patients to prioritize effective management of their pain.
ItemOpen Access
Identifying Somatic Variants using DNA Derived from Stereo-Electroencephalography Electrodes in Patients with Focal Epilepsy
(2024-11-04) Mascarenhas, Rumika; Klein, Karl Martin; Tarailo-Graovac, Maja; Kurrasch, Deborah; Wiebe, Samuel
Brain somatic variants play a crucial role in the etiology of focal epilepsy. Detecting these variants is challenging due to their presence in a subset of cells, resulting in a reduced variant allele frequency (VAF). Traditional methods rely on brain tissue obtained during resective epilepsy surgery, limiting accessibility and applicability, especially in patients with non-lesional epilepsies who are less likely to undergo surgery. In response to these limitations, a novel approach utilizes DNA extracted from depth electrodes employed in stereo-electroencephalography (SEEG) procedures. This method offers several advantages over resected brain tissue, such as the inclusivity of patients not undergoing surgery and access to multiple brain regions through implanted depth electrodes. Recent studies demonstrated the feasibility of detecting somatic variants using SEEG-derived DNA, highlighting its potential in non-lesional epilepsies. However, challenges remain, including potential cell contaminations and lower cell yields, necessitating DNA amplification that introduces associated artifacts. This thesis introduces an improved SEEG harvesting protocol addressing these issues. Our optimized technique purifies neuronal nuclei, mitigating cell contaminations, and incorporates a newer amplification method to minimize artifacts. Additionally, the thesis introduces the implementation of quality control steps for sample selection and a bioinformatic workflow to reduce artifactual and false positive variants, enhancing the reliability of downstream variant identification. With these improvements, this project aims to enhance the reliability and applicability of SEEG-derived DNA in understanding the molecular basis of focal epilepsy, paving the way for diagnosis and improved treatment strategies.
ItemOpen Access
Ultrasound Mediated Mild Hyperthermia Resolves Neuroinflammation in an Animal Model
(2024-11-01) Seasons, Graham; Pike, Bruce; Kuipers, Hedwich; Pichardo, Samuel; Dunn, Jeff
Chronic neuroinflammation is an often overlooked aspect of the development of neurodegenerative and autoimmune disease, especially in older populations, and there are few treatments capable of addressing this type of inflammation. We sought to address this gap by following up on our clinical finding where focused ultrasound resolved chronic radiation-related neuroinflammation Using ultrasound-mediated mild hyperthermia to treat chronic neuroinflammation in a preclinical mouse model, we investigated the impact on the immune response, and the resolution of inflammation. Seven days after peripheral infection, we targeted the mouse midbrain with focal hyperthermia (4 mins at 39 oC and 6 mins at 42 oC). Proteomic changes were analyzed, and demonstrated that hyperthermia reduced inflammation in female mice 24 hours after treatment, alleviating blood brain barrier disruption, antigen presentation, and anti-viral signalling. In contrast, male mice did not show a change in inflammatory mediators at 24 hours, but showed an upregulation in proteins associated with the heat shock response, chromatin maintenance, and chaperone mediated autophagy. At the cellular level, microglia and astrocytes demonstrated homeostatic phenotypes seven days after hyperthermia treatment in both males and females. We also investigated the role of the immunosuppressive CD200/CD200R signalling pathway in immune resolution, and discovered that it is dysregulated in chronic neuroinflammation – exacerbating inflammation in males, while maintaining a resolving function in females. Ultrasound mediated mild hyperthermia was able to restore homeostatic CD200/CD200R signalling, alleviating the pro-inflammatory rewiring observed in males. Consequently, we demonstrate that ultrasound mediated mild hyperthermia is capable of restoring the homeostatic function of receptors, and resolving chronic neuroinflammation across pathology, through the induction of the heat shock response. We propose a new application of clinically approved magnetic resonance guided focused ultrasound systems in the treatment of chronic neuroinflammation, with the potential for rapid clinical translation.
ItemOpen Access
Landscape transcriptomic analysis of bovine follicular cells during key phases of ovarian follicular development
(2024-10-28) Mogollón García, Henry D.; de Andrade Ferrazza, Rodrigo; Ochoa, Julian C.; de Athayde, Flávia F.; Vidigal, Pedro M. P.; Wiltbank, Milo; Kastelic, John P.; Sartori, Roberto; Ferreira, João C. P.
Abstract Background There are many gaps in our understanding of the mechanisms involved in ovarian follicular development in cattle, particularly regarding follicular deviation, acquisition of ovulatory capacity, and preovulatory changes. Molecular evaluations of ovarian follicular cells during follicular development in cattle, especially serial transcriptomic analyses across key growth phases, have not been reported. This study aims to address this gap by analyzing gene expression using RNA-seq in granulosa and antral cells recovered from ovarian follicular fluid during critical phases of ovarian follicular development in Holstein cows. Results Integrated analysis of gene ontology (GO), gene set enrichment (GSEA), protein–protein interaction (PPI), and gene topology identified that differentially expressed genes (DEGs) in the largest ovarian follicles at deviation (Dev) were primarily involved in FSH-negative feedback, steroidogenesis, cell proliferation, apoptosis, and the prevention of early follicle rupture. In contrast, DEGs in the second largest follicles (DevF2) were mainly related to loss of cell viability, apoptosis, and immune cell invasion. In the dominant (PostDev) and preovulatory (PreOv) follicles, DEGs were associated with vascular changes and inflammatory responses. Conclusions The transcriptome of ovarian follicular fluid cells had a predominance of granulosa cells in the dominant follicle at deviation, with upregulation of genes involved in cell viability, steroidogenesis, and apoptosis prevention, whereas in the non-selected follicle there was upregulation of cell death-related transcripts. Immune cell transcripts increased significantly after deviation, particularly in preovulatory follicles, indicating strong intrafollicular chemotactic activity. We inferred that immune cell invasion occurred despite an intact basal lamina, contributing to follicular maturation. Graphical Abstract
ItemOpen Access
Fenebrutinib, a Bruton’s tyrosine kinase inhibitor, blocks distinct human microglial signaling pathways
(2024-10-27) Langlois, Julie; Lange, Simona; Ebeling, Martin; Macnair, Will; Schmucki, Roland; Li, Cenxiao; DeGeer, Jonathan; Sudharshan, Tania J. J.; Yong, V. W.; Shen, Yun-An; Harp, Christopher; Collin, Ludovic; Keaney, James
Abstract Background Bruton’s tyrosine kinase (BTK) is an intracellular signaling enzyme that regulates B-lymphocyte and myeloid cell functions. Due to its involvement in both innate and adaptive immune compartments, BTK inhibitors have emerged as a therapeutic option in autoimmune disorders such as multiple sclerosis (MS). Brain-penetrant, small-molecule BTK inhibitors may also address compartmentalized neuroinflammation, which is proposed to underlie MS disease progression. BTK is expressed by microglia, which are the resident innate immune cells of the brain; however, the precise roles of microglial BTK and impact of BTK inhibitors on microglial functions are still being elucidated. Research on the effects of BTK inhibitors has been limited to rodent disease models. This is the first study reporting effects in human microglia. Methods Here we characterize the pharmacological and functional properties of fenebrutinib, a potent, highly selective, noncovalent, reversible, brain-penetrant BTK inhibitor, in human microglia and complex human brain cell systems, including brain organoids. Results We find that fenebrutinib blocks the deleterious effects of microglial Fc gamma receptor (FcγR) activation, including cytokine and chemokine release, microglial clustering and neurite damage in diverse human brain cell systems. Gene expression analyses identified pathways linked to inflammation, matrix metalloproteinase production and cholesterol metabolism that were modulated by fenebrutinib treatment. In contrast, fenebrutinib had no significant impact on human microglial pathways linked to Toll-like receptor 4 (TLR4) and NACHT, LRR and PYD domains-containing protein 3 (NLRP3) signaling or myelin phagocytosis. Conclusions Our study enhances the understanding of BTK functions in human microglial signaling that are relevant to MS pathogenesis and suggests that fenebrutinib could attenuate detrimental microglial activity associated with FcγR activation in people with MS.