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"Carroll, Simon"
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The functional and inflammatory response of brain endothelial cells to Toll-Like Receptor agonists
2018
Toll-Like receptors (TLRs) represent an important early warning mechanism for the immune system to detect infection or tissue damage. The focus of this research was to determine the neuroinflammatory responses to commercial TLR ligands and their effects on brain endothelial barrier strength. Using biosensor technology we screened TLR ligands to all human TLRs and found that the brain endothelial hCMVECs cell line only responded to Poly(I:C) (TLR3-ligand), LPS (TLR4-ligand) and Imiquimod (TLR7 ligand). Both Poly(I:C) and LPS induced pronounced pro-inflammatory cytokine secretion as expected, whereas Imiquimod did not induce secretion of any pro-inflammatory cytokines. Using ECIS technology to measure endothelial barrier function, LPS and Poly(I:C) both acutely reduced barrier-strength, whereas Imiquimod caused immediate and sustained strengthening of the barrier. Further cytokine and ECIS studies showed that Imiquimod could abrogate some of the pro-inflammatory responses to Poly(I:C) and LPS. Most surprisingly, PCR revealed that the hCMVECs lacked TLR7 but expressed both TLR3 and TLR4 and did not respond to other structurally different TLR7 ligands. These data demonstrate that brain endothelial cells can be regulated by TLR 3 and TLR4 ligands in a pro-inflammatory manner and have receptors to Imiquimod, distinct to the classical TLR7, that function in an anti-inflammatory manner.
Journal Article
Modulating Gradients in Regulatory Signals within Mesenchymal Stem Cell Seeded Hydrogels: A Novel Strategy to Engineer Zonal Articular Cartilage
2013
Engineering organs and tissues with the spatial composition and organisation of their native equivalents remains a major challenge. One approach to engineer such spatial complexity is to recapitulate the gradients in regulatory signals that during development and maturation are believed to drive spatial changes in stem cell differentiation. Mesenchymal stem cell (MSC) differentiation is known to be influenced by both soluble factors and mechanical cues present in the local microenvironment. The objective of this study was to engineer a cartilaginous tissue with a native zonal composition by modulating both the oxygen tension and mechanical environment thorough the depth of MSC seeded hydrogels. To this end, constructs were radially confined to half their thickness and subjected to dynamic compression (DC). Confinement reduced oxygen levels in the bottom of the construct and with the application of DC, increased strains across the top of the construct. These spatial changes correlated with increased glycosaminoglycan accumulation in the bottom of constructs, increased collagen accumulation in the top of constructs, and a suppression of hypertrophy and calcification throughout the construct. Matrix accumulation increased for higher hydrogel cell seeding densities; with DC further enhancing both glycosaminoglycan accumulation and construct stiffness. The combination of spatial confinement and DC was also found to increase proteoglycan-4 (lubricin) deposition toward the top surface of these tissues. In conclusion, by modulating the environment through the depth of developing constructs, it is possible to suppress MSC endochondral progression and to engineer tissues with zonal gradients mimicking certain aspects of articular cartilage.
Journal Article
Safety and anti-tumour activity of the IgE antibody MOv18 in patients with advanced solid tumours expressing folate receptor-alpha: a phase I trial
2023
All antibodies approved for cancer therapy are monoclonal IgGs but the biology of IgE, supported by comparative preclinical data, offers the potential for enhanced effector cell potency. Here we report a Phase I dose escalation trial (NCT02546921) with the primary objective of exploring the safety and tolerability of MOv18 IgE, a chimeric first-in-class IgE antibody, in patients with tumours expressing the relevant antigen, folate receptor-alpha. The trial incorporated skin prick and basophil activation tests (BAT) to select patients at lowest risk of allergic toxicity. Secondary objectives were exploration of anti-tumour activity, recommended Phase II dose, and pharmacokinetics. Dose escalation ranged from 70 μg–12 mg. The most common toxicity of MOv18 IgE is transient urticaria. A single patient experienced anaphylaxis, likely explained by detection of circulating basophils at baseline that could be activated by MOv18 IgE. The BAT assay was used to avoid enrolling further patients with reactive basophils. The safety profile is tolerable and maximum tolerated dose has not been reached, with evidence of anti-tumour activity observed in a patient with ovarian cancer. These results demonstrate the potential of IgE therapy for cancer.
IgE antibodies have shown anti-tumor activity, even superior to IgG, in preclinical models. However, all monoclonal antibodies in clinical use for cancer therapy are members of the IgG class. Here the authors report the results of a phase I clinical trial of a chimeric monoclonal IgE antibody, specific for the folate receptor-alpha, in patients with advanced solid cancer.
Journal Article
Cyclic Tensile Strain Can Play a Role in Directing both Intramembranous and Endochondral Ossification of Mesenchymal Stem Cells
by
Kelly, Daniel J.
,
Buckley, Conor T.
,
Carroll, Simon F.
in
Bioengineering and Biotechnology
,
endochondral ossification
,
intramembranous ossification
2017
Successfully regenerating damaged or diseased bone and other joint tissues will require a detailed understanding of how joint specific environmental cues regulate the fate of progenitor cells that are recruited or delivered to the site of injury. The goal of this study was to explore the role of cyclic tensile strain (CTS) in regulating the initiation of mesenchymal stem cell/multipotent stromal cell (MSC) differentiation, and specifically their progression along the endochondral pathway. To this end, we first explored the influence of CTS on the differentiation of MSCs in the absence of any specific growth factor, and secondly, we examined the influence of the long-term application of this mechanical stimulus on markers of endochondral ossification in MSCs maintained in chondrogenic culture conditions. A custom bioreactor was developed to apply uniaxial tensile deformation to bone marrow-derived MSCs encapsulated within physiological relevant 3D fibrin hydrogels. Mechanical loading, applied in the absence of soluble differentiation factors, was found to enhance the expression of both tenogenic (COL1A1) and osteogenic markers (BMP2, RUNX2, and ALPL), while suppressing markers of adipogenesis. No evidence of chondrogenesis was observed, suggesting that CTS can play a role in initiating direct intramembranous ossification. During long-term culture in the presence of a chondrogenic growth factor, CTS was shown to induce MSC re-organization and alignment, increase proteoglycan and collagen production, and to enhance the expression of markers associated with endochondral ossification (BMP2, RUNX2, ALPL, OPN, and COL10A1) in a strain magnitude-dependent manner. Taken together, these findings indicate that tensile loading may play a key role in promoting both intramembranous and endochondral ossification of MSCs in a context-dependent manner. In both cases, this loading-induced promotion of osteogenesis was correlated with an increase in the expression of the osteogenic growth factor BMP2. The results of this study demonstrate the potent role that extrinsic mechanical loading plays in guiding stem cell fate, which must be carefully considered when designing cell and tissue-engineering therapies if they are to realize their clinical potential.
Journal Article
Measuring and Modeling Oxygen Transport and Consumption in 3D Hydrogels Containing Chondrocytes and Stem Cells of Different Tissue Origins
by
Kelly, Daniel J.
,
Buckley, Conor T.
,
Carroll, Simon F.
in
Bioengineering and Biotechnology
,
cartilage
,
cellular metabolism
2021
Understanding how the local cellular environment influences cell metabolism, phenotype and matrix synthesis is crucial to engineering functional tissue grafts of a clinically relevant scale. The objective of this study was to investigate how the local oxygen environment within engineered cartilaginous tissues is influenced by factors such as cell source, environmental oxygen tension and the cell seeding density. Furthermore, the subsequent impact of such factors on both the cellular oxygen consumption rate and cartilage matrix synthesis were also examined. Bone marrow derived stem cells (BMSCs), infrapatellar fat pad derived stem cells (FPSCs) and chondrocytes (CCs) were seeded into agarose hydrogels and stimulated with transforming growth factor-β3 (TGF- β3). The local oxygen concentration was measured within the center of the constructs, and numerical modeling was employed to predict oxygen gradients and the average oxygen consumption rate within the engineered tissues. The cellular oxygen consumption rate of hydrogel encapsulated CCs remained relatively unchanged with time in culture. In contrast, stem cells were found to possess a relatively high initial oxygen consumption rate, but adopted a less oxidative, more chondrocyte-like oxygen consumption profile following chondrogenic differentiation, resulting in net increases in engineered tissue oxygenation. Furthermore, a greater reduction in oxygen uptake was observed when the oxygen concentration of the external cell culture environment was reduced. In general, cartilage matrix deposition was found to be maximal in regions of low oxygen, but collagen synthesis was inhibited in very low (less than 2%) oxygen regions. These findings suggest that promoting an oxygen consumption profile similar to that of chondrocytes might be considered a key determinant to the success of stem cell-based cartilage tissue engineering strategies.
Journal Article
Long COVID in long-term care: a rapid realist review
2023
ObjectivesThe goals of this rapid realist review were to ask: (a) what are the key mechanisms that drive successful interventions for long COVID in long-term care (LTC) and (b) what are the critical contexts that determine whether the mechanisms produce the intended outcomes?DesignRapid realist review.Data sourcesMedline, CINAHL, Embase, PsycINFO and Web of Science for peer-reviewed literature and Google for grey literature were searched up to 23 February 2023.Eligibility criteriaWe included sources focused on interventions, persons in LTC, long COVID or post-acute phase at least 4 weeks following initial COVID-19 infection and ones that had a connection with source materials.Data extraction and synthesisThree independent reviewers searched, screened and coded studies. Two independent moderators resolved conflicts. A data extraction tool organised relevant data into context-mechanism-outcome configurations using realist methodology. Twenty-one sources provided 51 intervention data excerpts used to develop our programme theory. Synthesised findings were presented to a reference group and expert panel for confirmatory purposes.ResultsFifteen peer-reviewed articles and six grey literature sources were eligible for inclusion. Eleven context-mechanism-outcome configurations identify those contextual factors and underlying mechanisms associated with desired outcomes, such as clinical care processes and policies that ensure timely access to requisite resources for quality care delivery, and resident-centred assessments and care planning to address resident preferences and needs. The underlying mechanisms associated with enhanced outcomes for LTC long COVID survivors were: awareness, accountability, vigilance and empathetic listening.ConclusionsAlthough the LTC sector struggles with organisational capacity issues, they should be aware that comprehensively assessing and monitoring COVID-19 survivors and providing timely interventions to those with long COVID is imperative. This is due to the greater care needs of residents with long COVID, and coordinated efficient care is required to optimise their quality of life.
Journal Article
Vicious Pranks
2019
This essay juxtaposes vicious pranks in François Rabelais’s Pantagruel (1532) and William Shakespeare’s Twelfth Night (1601) in order to describe a form of comic violence that functions as a knowledge claim about its target. In each case, the event of injury conveys an eager insistence on the truth of some taken-for-granted assertion about the injured party. I discuss the role of comic atmosphere in encouraging such performative incuriosity, and I describe those strategies by which cruel pranksters enlist the participation of readers and spectators. Ultimately, I show that Shakespeare parts ways with Rabelais by undermining epistemological security, the desire for which helps motivate both the prank and whatever affirmation it elicits from witnesses.
Journal Article
Treatment of tungiasis using a tea tree oil-based gel formulation: protocol for a randomised controlled proof-of-principle trial
by
Abrha, Solomon
,
Heukelbach, Jorg
,
Feldmeier, Hermann
in
Advisors
,
Bacterial infections
,
Caregivers
2021
IntroductionTungiasis (sand flea disease or jigger infestation) is a neglected tropical disease caused by penetration of female sand fleas, Tunga penetrans, in the skin. The disease inflicts immense pain and suffering on millions of people, particularly children, in Latin America, the Caribbean and sub-Saharan Africa. Currently, there is no standard treatment for tungiasis, and a simple, safe and effective tungiasis treatment option is required. Tea tree oil (TTO) has long been used as a parasiticidal agent against ectoparasites such as headlice, mites and fleas with proven safety and efficacy data. However, current data are insufficient to warrant a recommendation for its use in tungiasis. This trial aims to generate these data by comparing the safety and efficacy of a 5% (v/w) TTO proprietary gel formulation with 0.05% (w/v) potassium permanganate (KMnO4) solution for tungiasis treatment.Methods and analysisThis trial is a randomised controlled trial (RCT) in primary schools (n=8) in South-Western Kenya. The study will include school children (n=88) aged 6–15 years with a confirmed diagnosis of tungiasis. The participants will be randomised in a 1:1 ratio to receive a 3-day two times a day treatment of either 5% TTO gel or 0.05% KMnO4 solution. Two viable embedded sandflea lesions per participant will be targeted and the viability of these lesions will be followed throughout the study using a digital handheld microscope. The primary outcome is the proportion of observed viable embedded sand fleas that have lost viability (non-viable lesions) by day 10 (9 days after first treatment). Secondary outcomes include improvement in acute tungiasis morbidities assessed using a validated severity score for tungiasis, safety assessed through adverse events and product acceptability assessed by interviewing the participants to rate the treatment in terms of effectiveness, side effects, convenience, suitability and overall satisfaction.Ethics and disseminationThe trial protocol has been reviewed and approved by the University of Canberra Human Research Ethics Committee (HREC-2019-2114). The findings of the study will be presented at scientific conferences and published in a peer-reviewed journal.Trial registration numbersAustralian New Zealand Clinical Trials Registry (ACTRN12619001610123); PACTR202003651095100 and U1111-1243-2294.
Journal Article
Supporting Healthy Aging through the Scale-Up, Spread, and Sustainability of Assistive Technology Implementation: A Rapid Realist Review of Participatory Co-Design for Assistive Technology with Older Adults
by
Shannon, Tracey
,
Cervantes, Matilde N
,
Saini Manik
in
Adaptive technology
,
Co-design
,
COVID-19
2021
Objective: To identify the key mechanisms, contexts, and outcomes that drive the successful participatory co-design of assistive technologies. Method: A rapid realist review was conducted using a systematic search strategy. After screening, a final set of 28 articles were included. Articles were analyzed for evidence relevant to our initial program theory (IPT), and context-mechanism-outcome configurations were developed, resulting in a revised program theory. Results: All 28 articles included were highly relevant to the IPT, and had sufficient detail regarding the process of participatory co-design. The findings of this review highlight several key context-mechanism-outcome configurations as potential patterns in the data under the two dimensions of the evolving program theory: knowledge integration and the ethico-political dimension. Discussion: This review revealed the key mechanisms of mutual awareness, mutual learning, trust, and reciprocity that need to be taken into account in AT development and assessment. We concluded that participatory co-design requires a restructuring of power relations between end-users and those traditionally in control of technology design. These findings inform the development and assessment of AT for older adults and help guide policy/decision-makers to move forward with the now urgent agenda for scale-up and spread, initiated by the burning platform of the COVID-19 pandemic.
Journal Article
Large-System Transformation in Health Care: A Realist Review
2012
Context: An evidence base that addresses issues of complexity and context is urgently needed for large—system transformation (LST) and health care reform. Fundamental conceptual and methodological challenges also must be addressed. The Saskatchewan Ministry of Health in Canada requested a six-month synthesis project to guide four major policy development and strategy initiatives focused on patient- and family-centered care, primary health care renewal, quality improvement, and surgical wait lists. The aims of the review were to analyze examples of successful and less successful transformation initiatives, to synthesize knowledge of the underlying mechanisms, to clarify the role of government, and to outline options for evaluation. Methods: We used realist review, whose working assumption is that a particular intervention triggers particular mechanisms of change. Mechanisms may be more or less effective in producing their intended outcomes, depending on their interaction with various contextual factors. We explain the variations in outcome as the interplay between context and mechanisms. We nested this analytic approach in a macro framing of complex adaptive systems (CAS). Findings: Our rapid realist review identified five \"simple rules\" of LST that were likely to enhance the success of the target initiatives: (1) blend designated leadership with distributed leadership; (2) establish feedback loops; (3) attend to history; (4) engage physicians; and (5) include patients and families. These principles play out differently in different contexts affecting human behavior (and thereby contributing to change) through a wide range of different mechanisms. Conclusions: Realist review methodology can be applied in combination with a complex system lens on published literature to produce a knowledge synthesis that informs a prospective change effort in large-system transformation. A collaborative process engaging both research producers and research users contributes to local applications of universal principles and mid-range theories, as well as to a more robust knowledge base for applied research. We conclude with suggestions for the future development of synthesis and evaluation methods.
Journal Article