Pharmacology and Therapeutics - Journal Articles
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- ItemThe effect of fingolimod on regulatory T cells in a mouse model of brain ischaemia(BioMed Central Ltd, 2021) Malone, Kyle; Diaz Diaz, Andrea C.; Shearer, Jennifer A.; Moore, Anne C.; Waeber, Christian; Science Foundation Ireland; Irish Research Council; Health Research Board; European CommissionBackground: The role of the immune system in stroke is well-recognised. Fingolimod, an immunomodulatory agent licensed for the management of relapsing-remitting multiple sclerosis, has been shown to provide benefit in rodent models of stroke. Its mechanism of action, however, remains unclear. We hypothesised fingolimod increases the number and/or function of regulatory T cells (Treg), a lymphocyte population which promotes stroke recovery. The primary aim of this study was to rigorously investigate the effect of fingolimod on Tregs in a mouse model of brain ischaemia. The effect of fingolimod in mice with common stroke-related comorbidities (ageing and hypercholesteremia) was also investigated. Methods: Young (15–17 weeks), aged C57BL/6 mice (72–73 weeks), and ApoE?/? mice fed a high-fat diet (20–21 weeks) underwent permanent electrocoagulation of the left middle cerebral artery. Mice received either saline or fingolimod (0.5 mg/kg or 1 mg/kg) at 2, 24, and 48 h post-ischaemia via intraperitoneal injection. Another cohort of young mice (8–9, 17–19 weeks) received short-term (5 days) or long-term (10 days) fingolimod (0.5 mg/kg) treatment. Flow cytometry was used to quantify Tregs in blood, spleen, and lymph nodes. Immunohistochemistry was used to quantify FoxP3+ cell infiltration into the ischaemic brain. Results: Fingolimod significantly increased the frequency of Tregs within the CD4+ T cell population in blood and spleen post-ischaemia in all three mouse cohorts compared to untreated ischemic mice. The highest splenic Treg frequency in fingolimod-treated mice was observed in ApoE?/? mice (9.32 ± 1.73% vs. 7.8 ± 3.01% in young, 6.09 ± 1.64% in aged mice). The highest circulating Treg frequency was also noted in ApoE?/? mice (8.39 ± 3.26% vs. 5.43 ± 2.74% in young, 4.56 ± 1.60% in aged mice). Fingolimod significantly increased the number of FoxP3+ cells in the infarct core of all mice. The most pronounced effects were seen when mice were treated for 10 days post-ischaemia. Conclusions: Fingolimod increases Treg frequency in spleen and blood post-ischaemia and enhances the number of FoxP3+ cells in the ischaemic brain. The effect of fingolimod on this regulatory cell population may underlie its neuroprotective activity and could be exploited as part of future stroke therapy.
- ItemEthanolamine: A potential promoiety with additional effects in the brain [Mini review](Bentham Science, 2020-12-11) Gwanyanya, Asfree; Godsmark, Christie Nicole; Kelly-Laubscher, RoisinEthanolamine is a bioactive molecule found in several cells, including those in the central nervous system (CNS). In the brain, ethanolamine and ethanolamine-related molecules have emerged as prodrug moieties that can promote drug movement across the blood-brain barrier. This improvement in the ability to target drugs to the brain may also mean that in the process ethanolamine concentrations in the brain are increased enough for ethanolamine to exert its own neurological ac-tions. Ethanolamine and its associated products have various positive functions ranging from cell signaling to molecular storage, and alterations in their levels have been linked to neurodegenerative conditions such as Alzheimer's disease. This mini-review focuses on the effects of ethanolamine in the CNS and highlights the possible implications of these effects for drug design.
- ItemThe potential of student narratives to enhance quality in higher education(Taylor & Francis, 2017-04-10) Hamshire, Claire; Forsyth, Rachel; Bell, Amani; Benton, Matthew; Kelly-Laubscher, Roisin; Paxton, Moragh; Wolfgramm-Foliaki, `EmaUniversity policies are increasingly developed with reference to students’ learning experiences, with a focus on the concept of the ‘student voice’. Yet the ‘student voice’ is difficult to define and emphasis is often placed on numerical performance indicators. A diverse student population has wide-ranging educational experiences, which may not be easily captured within the broad categories provided by traditional survey tools, which can drown out the rich, varied and gradual processes of individual development. There is no single tool that can be used to measure students’ experiences. This paper draws on findings from four narrative inquiry studies, carried out in the United Kingdom, Australia, South Africa and New Zealand, to illustrate how a narrative approach could be used to complement performance indicators. This provides a richer context for educators’ understanding of students’ experiences and for supporting and setting institutional agendas.
- ItemCardioprotective effect of fingolimod against calcium paradox-induced myocardial injury in the isolated rat heart(Canadian Science Publishing, 2021-09-24) Alatrag, Fatma; Amoni, Matthew; Kelly-Laubscher, Roisin; Gwanyanya, Asfree; South African Medical Research Council; National Research FoundationFingolimod (FTY720) inhibits Ca2+-permeable, Mg2+-sensitive channels called transient receptor potential melastatin 7 (TRPM7), but its effects on Ca2+ paradox (CP)-induced myocardial damage have not been evaluated. We studied the effect of FTY720 on CP-induced myocardial damage, and used other TRPM7 channel inhibitors nordihydroguaiaretic acid (NDGA) and Mg2+ to test if any effect of FTY720 was via TRPM7 inhibition. Langendorff-perfused Wistar rat hearts were treated with FTY720 or NDGA and subjected to a CP protocol consisting of Ca2+ depletion followed by Ca2+ repletion. Hearts of rats pre-treated with MgSO4 were also subjected to CP. Hemodynamic parameters were measured using an intraventricular balloon, and myocardial infarct size was quantified using triphenyltetrazolium chloride stain. TRPM7 proteins in ventricular tissue were detected using immunoblot analysis. FTY720, but not NDGA, decreased CP-induced infarct size. Both FTY720 and NDGA minimized the CP-induced elevation of left ventricular end-diastolic pressure, but only FTY720 ultimately improved ventricular developed pressure. Mg2+ pre-treatment had effect neither on CP-induced infarct size, hemodynamic parameters during CP, nor the level TRPM7 protein expression in ventricular tissue. Overall, FTY720 attenuated CP-induced myocardial damage, with potential therapeutic implications on Ca2+-mediated cardiotoxicity. However, the cardioprotective mechanism of FTY720 seems to be unrelated to TRPM7 channel modulation.
- ItemCardioprotective and anti-arrhythmic effects of magnesium pretreatment against ischaemia/reperfusion injury in isoprenaline-induced hypertrophic rat heart(Springer, 2015-12-22) Amoni, Matthew; Kelly-Laubscher, Roisin; Petersen, Morea; Gwanyanya, Asfree; University of Cape Town; National Research FoundationThe effects of magnesium (Mg2+) on ischaemic complications of pathological cardiac hypertrophy are unclear. In this study, we investigated effects of Mg2+ pretreatment on ischaemia/reperfusion (I/R) injury in isoprenaline (ISO)-induced hypertrophic hearts. Wistar rats were treated for 7 days with different combinations of ISO (1.25 mg/kg) subcutaneously, MgSO4 (270 mg/kg) intraperitoneally, or vehicle (saline). On the eighth day, hearts were either subjected to regional I/R during Langendorff perfusion or histologically stained with haematoxylin and eosin and Masson’s trichrome. Haemodynamic and electrocardiographic parameters were recorded using the PowerLab data-acquisition system. Infarcts were identified by triphenyltetrazolium chloride staining. Plasma Mg2+ was measured using photometric assays. Mg2+ pretreatment significantly decreased I/R-induced infarct size (p = 0.001) and the overall arrhythmia score (p < 0.001) of I/R-induced ventricular ectopics, ventricular tachycardia, and ventricular fibrillation in hypertrophic hearts, but not non-hypertrophied hearts. Mg2+ also improved post-I/R left ventricular developed pressure in hypertrophic hearts. However, Mg2+ did not reverse the ISO-induced myocyte thickening and interstitial fibrosis or increases in heart weight. Plasma Mg2+ was not different among treatment groups. These results suggest that Mg2+ pretreatment may protect against I/R-induced injury and malignant arrhythmias in hypertrophic hearts, possibly via mechanisms unrelated to long-lasting changes in plasma Mg2+ or prevention of structural changes such as fibrosis.