Publications by authors named "Ayesha De Souza"

Background: The use of donation after circulatory death (DCD) kidneys for transplantation is increasing. Subsequent delayed graft function is related to ischaemia/reperfusion injury (I/R), warm ischaemia (WI) being one of the main contributing factors. This proteomics study aimed to identify candidate biomarkers of WI.

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Early pro-angiogenic cells (EPCs) have been shown to be involved in neovascularization, angiogenesis and re-endothelialization and cathepsin L inhibition blunted their pro-angiogenic effect. In the present study, we have analysed and mapped the proteome and secretome of human EPCs, utilizing a combination of difference in-gel electrophoresis (DIGE) and shotgun proteomics. A population of 206 protein spots were analysed, with 171 being identified in the cellular proteome of EPCs.

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Congestive heart failure (CHF) leads to atrial structural remodelling and increased susceptibility to atrial fibrillation. The underlying molecular mechanisms are poorly understood. We applied high-throughput proteomic and metabolomic analysis to left-atrial cardiomyocytes and tissues obtained from sham and ventricular-tachypaced (VTP, 240 bpm × 24 h and × 2 weeks) CHF dogs.

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Background: Atrial fibrillation (AF) is the most common heart rhythm abnormality after cardiac surgery. It increases morbidity and prolongs hospital stay. A role for statins in the prevention of AF has been suggested.

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We have recently demonstrated that stem cell antigen 1-positive (Sca-1(+)) progenitors exist in the vascular adventitia of apolipoprotein E-deficient (apoE(-/-)) mice and contribute to smooth muscle cell (SMC) accumulation in vein graft atherosclerosis. Using a combined proteomic and metabolomic approach, we now characterize these local progenitors, which participate in the formation of native atherosclerotic lesions in chow-fed apoE(-/-) mice. Unlike Sca-1(+) progenitors from embryonic stem cells, the resident Sca-1(+) stem cell population from the vasculature acquired a mature aortic SMC phenotype after platelet-derived growth factor-BB stimulation.

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Objectives: We sought to decipher metabolic processes servicing the increased energy demand during persistent atrial fibrillation (AF) and to ascertain whether metabolic derangements might instigate this arrhythmia.

Background: Whereas electrical, structural, and contractile remodeling processes are well-recognized contributors to the self-perpetuating nature of AF, the impact of cardiac metabolism upon the persistence/initiation of this resilient arrhythmia has not been explored in detail.

Methods: Human atrial appendage tissues from matched cohorts in sinus rhythm (SR), from those who developed AF post-operatively, and from patients in persistent AF undergoing cardiac surgery were analyzed using a combined metabolomic and proteomic approach.

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Two-dimensional gel electrophoresis (2-DE) combined with protein identification by mass spectrometry (MS) is currently the method of choice in the majority of proteomic projects. Novel gel-free technologies have been developed but 2-DE remains the technique of choice for quantitative expression profiling of large sets of complex protein mixtures such as whole cell/tissue lysates. Solubilized proteins are separated in the first dimension according to their charge properties (isoelectric point, pI) by isoelectric focusing (IEF) under denaturing conditions, followed by their separation in the second dimension by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), according to their relative molecular mass (Mr).

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Proteomics generates information on expressed proteins, and laser microdissection (LMD) is a method that allows enrichment of specific cell types from complex heterogeneous tissue. Together they provide a powerful tool for functional genomic research. Here, we have investigated (i) the effects of fixation and staining on cardiac proteins separated by two-dimensional gel electrophoresis (2-DE) and (ii) feasibility of using LMD to separately prepare myocytes and blood vessels for 2-DE gel analysis.

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