Biology subjects

McKenna, C.

Publications and source records attributed to McKenna, C..

4 recordsLinked to original sources

bioRxiv2023

Extracellular vesicles from patients with coronary artery disease (CAD) demonstrate enhanced pro-coagulatory activity.

AimsExtracellular vesicles (EVs) carry unique repertoires of biologically active cargo that hold promise as novel biomarkers and future interventional targets for cardiovascular diseases (CVDs). However, it is unclear as to how the number, location, cellular origin, and size of these EVs within the circulation relate to the development of CVDs such as coronary artery disease (CAD). The current study compared these novel markers in arterial and venous blood samples in individuals undergoing coronary assessment with angiography.. EVs were then characterized from those presenting with and without CAD. Methods and ResultsArterial and venous blood samples were collected from individuals with confirmed CAD following coronary angiography and a matched cohort in whom there was no evidence of disease. EV fractions were isolated from 500{micro}L of platelet free plasma (PFP) by size exclusion chromatography. EVs were analyzed by Nanoparticle Tracking Analysis and flow cytometry to characterize number, size and cellular origin. A thrombin generation assay was used to assess the pro-coagulatory activity of the isolated circulating EVs. Proteomics was used to determine the protein cargo carried within the EVs. Coagulatory activity of EVs isolated from CAD patients was significantly higher in when compared to controls, although the numbers of EVs did not differ. There were higher numbers of endothelial-derived EVs in arterial blood compared with venous blood. Linear regression models revealed that plasma triacylglycerol concentration and age independently predicted circulating EV numbers in CAD patients. Proteomics revealed several proteins associated with coagulation upregulated in patients with CAD. ConclusionsAlthough the absolute numbers of EVs in CAD patients were not elevated, EVs in CAD patients had greater pro-coagulant activity, highlighting a potentially important role for EVs in the pathogenesis of CAD. Clinical PerspectiveO_ST_ABSWhat is new?C_ST_ABSO_LICAD patients displayed a greater EV-induced thrombin generation capability when compated to those with no disease. C_LIO_LIThe proteomic profile of arterial-derived EVs in patients with CAD demonstrated several proteins associated with coagulation that may be a risk factor for developing a future event. C_LI What are the clinical implications?O_LIThe identification of EVs in patients with CAD with upregulated coagulation proteins may be a novel biomarker for the development of future events and may identify a high risk patient group that may benefit for more aggressive cardiovascular risk intervention. C_LI

physiology↗

bioRxiv2023

Mitochondrial dysfunction underlies impaired neurovascular coupling following traumatic brain injury

Traumatic brain injury (TBI) involves an acute injury (primary damage), which may evolve in the hours to days after impact (secondary damage). Seizures and cortical spreading depolarization (CSD) are metabolically demanding processes that may worsen secondary brain injury. Metabolic stress has been associated with mitochondrial dysfunction, including impaired calcium homeostasis, reduced ATP production, and elevated ROS production. However, the association between mitochondrial impairment and vascular function after TBI is poorly understood. Here, we explored this association using a rodent closed head injury model. CSD resulted in neurobehavioral decline after TBI. Craniotomy was performed to elicit CSD via electrical stimulation or to induce seizures via 4-aminopyridine application. We measured vascular dysfunction following CSDs and seizures in TBI animals using laser doppler flowmetry. We observed a more profound reduction in local cortical blood flow in TBI animals compared to healthy controls. Following TBI, CSD resulted in mitochondrial dysfunction and pathological signs of increased oxidative stress adjacent to the vasculature. We explored these findings further using electron microscopy and found that TBI and CSDs resulted in vascular morphological changes and mitochondrial cristae damage in astrocytes, pericytes and endothelial cells. Overall, we provide evidence that CSDs induce mitochondrial dysfunction, impaired cortical blood flow, and neurobehavioral deficits in the setting of TBI. HighlightsCortical spreading depolarization after TBI causes behavioral decline in rats. Vasoconstriction and oligemia after cortical spreading depolarization is worse in TBI brains. Spreading depolarization causes impaired mitochondrial function. TBI and spreading depolarization result in constricted vessels and increased pericyte size. TBI and spreading depolarization result in mitochondrial damage in vascular cells. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=124 SRC="FIGDIR/small/549872v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@176a9a6org.highwire.dtl.DTLVardef@17bfc19org.highwire.dtl.DTLVardef@e3d74dorg.highwire.dtl.DTLVardef@4c194e_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2021

Comparative genomics and pangenomics of vancomycin resistant and susceptible Enterococcus faecium from Irish hospitals across 20 years

Enterococcus faecium has emerged as an important nosocomial pathogen, which is increasingly difficult to treat due to the genetic acquisition of vancomycin resistance. Ireland exhibits a recalcitrant vancomycin resistant bloodstream infection rate compared to other developed countries. A set of 28 vancomycin resistant isolates was sequenced to construct a dataset alongside 61 other publicly available Irish genomes. This dataset was extensively analysed using in-silico methodologies and uncovered distinct evolutionary, coevolutionary, and clinically relevant population trends. These results suggest that a stable (in terms of genome size, GC%, and number of genes), yet genetically diverse population (in terms of gene content) of Enterococcus faecium persist in Ireland with acquired resistance arising via plasmid acquisition (vanA) or to a lesser extent, chromosomal recombination (vanB). Population analysis described five clusters with one cluster partitioned into four clades which transcend isolation dates. Pangenomic and recombination analyses revealed an open (whole genome and chromosomal specific) pangenome illustrating a rampant evolutionary pattern. Comparative resistomics and virulomics uncovered distinct chromosomal and mobilomal propensity for multidrug resistance, widespread chromosomal point-mutation mediated resistance, and chromosomal harboured arsenals of virulence factors. Comparative phagomics revealed a core prophagome of three prophages throughout the dataset. Interestingly, a potential difference in biofilm formation strategies was highlighted by coevolutionary analysis, suggesting differential biofilm genotypes between vanA and vanB isolates. These results highlight the evolutionary history of Irish Enterococcus faecium isolates and may provide an insight into underlying infection dynamics in a clinical setting.

microbiology↗

bioRxiv2021

Evaluating the feasibility and efficacy of a dual-modality nanoparticle contrast agent (Nanotrast-CF800) for image-guided sentinel lymph node mapping in the oral cavity of healthy dogs

A combination of pre- and intraoperative sentinel lymph node (SLN) mapping techniques has been suggested to optimize SLN detection. A novel liposomal nanoparticle, Nanotrast-CF800 (CF800), utilizes computed tomography lymphography (CTL) and near infrared fluorescence imaging (NIRF) for image-guided surgery and SLN mapping. This novel tracer agent has not been evaluated in companion animals. The objective of this study was to evaluate the feasibility and efficacy of CF800 for SLN mapping in the oral cavity of healthy dogs and to report any local adverse effects. Six healthy adult purpose-bred research dogs randomly received either 1 mL (group 1) or 2 mL (group 2) of CF800 injected into the submucosa at the level of the right canine maxillary tooth. CTL and percutaneous NIRF were performed at 1, 3, and 10 minutes, then 1, 2, 4, 7, and 10 days post-injection (p.i). Overall, both CTL and NIRF identified SLNs in all dogs. The overall peak mean contrast enhancement of the SLNs was 73.98 HU (range 63.45-86.27 HU) at 2 days p.i. Peak fluorescence of the SLN occurred at 1 day p.i. The agent was retained within the SLN for at least 7 days for CTL and 4 days for NIRF. No adverse effects were observed. Local administration of CF800 was simple and feasible for the detection of SLNs using CTL+NIRF in the head and neck of healthy dogs and was not associated with significant local adverse events.

cancer biology↗