Fenofibrate in the management of AbdoMinal aortic anEurysm (FAME): Study protocol for a randomised controlled trial

Background: Abdominal aortic aneurysm (AAA) is a slowly progressive destructive process of the main abdominal artery. Experimental studies indicate that fibrates exert beneficial effects on AAAs by mechanisms involving both serum lipid modification and favourable changes to the AAA wall. Methods/design: Fenofibrate in the management of AbdoMinal aortic anEurysm (FAME) is a multicentre, randomised, double-blind, placebo-controlled clinical trial to assess the effect of orally administered therapy with fenofibrate on key pathological markers of AAA in patients undergoing open AAA repair. A total of 42 participants scheduled for an elective open AAA repair will be randomly assigned to either 145 mg of fenofibrate per day or identical placebo for a minimum period of 2 weeks prior to surgery. Primary outcome measures will be macrophage number and osteopontin (OPN) concentration within the AAA wall as well as serum concentrations of OPN. Secondary outcome measures will include levels of matrix metalloproteinases and proinflammatory cytokines within the AAA wall, periaortic fat and intramural thrombus and circulating concentrations of AAA biomarkers. Discussion: At present, there is no recognised medical therapy to limit AAA progression. The FAME trial aims to assess the ability of fenofibrate to alter tissue markers of AAA pathology. Trial registration: Australian New Zealand Clinical Trials Registry, ACTRN12612001226897. Registered on 20 November 2012. © 2017 The Author(s)

Molecular and Evolutionary Bases of Within-Patient Genotypic and Phenotypic Diversity in Escherichia coli Extraintestinal Infections

Although polymicrobial infections, caused by combinations of viruses, bacteria, fungi and parasites, are being recognised with increasing frequency, little is known about the occurrence of within-species diversity in bacterial infections and the molecular and evolutionary bases of this diversity. We used multiple approaches to study the genomic and phenotypic diversity among 226 Escherichia coli isolates from deep and closed visceral infections occurring in 19 patients. We observed genomic variability among isolates from the same site within 11 patients. This diversity was of two types, as patients were infected either by several distinct E. coli clones (4 patients) or by members of a single clone that exhibit micro-heterogeneity (11 patients); both types of diversity were present in 4 patients. A surprisingly wide continuum of antibiotic resistance, outer membrane permeability, growth rate, stress resistance, red dry and rough morphotype characteristics and virulence properties were present within the isolates of single clones in 8 of the 11 patients showing genomic micro-heterogeneity. Many of the observed phenotypic differences within clones affected the trade-off between self-preservation and nutritional competence (SPANC). We showed in 3 patients that this phenotypic variability was associated with distinct levels of RpoS in co-existing isolates. Genome mutational analysis and global proteomic comparisons in isolates from a patient revealed a star-like relationship of changes amongst clonally diverging isolates. A mathematical model demonstrated that multiple genotypes with distinct RpoS levels can co-exist as a result of the SPANC trade-off. In the cases involving infection by a single clone, we present several lines of evidence to suggest diversification during the infectious process rather than an infection by multiple isolates exhibiting a micro-heterogeneity. Our results suggest that bacteria are subject to trade-offs during an infectious process and that the observed diversity resembled results obtained in experimental evolution studies. Whatever the mechanisms leading to diversity, our results have strong medical implications in terms of the need for more extensive isolate testing before deciding on antibiotic therapies

Vitamin D deficiency promotes large rupture-prone abdominal aortic aneurysms and cholecalciferol supplementation limits progression of aneurysms in a mouse model

202101 bcrcVersion of RecordPublishe

Proteomic and genomic analyses suggest the association of apolipoprotein C1 with abdominal aortic aneurysm.

PURPOSE: Abdominal aortic aneurysm (AAA) is an important cause of mortality in the elderly. Mouse models are widely used to investigate AAA pathogenesis but their suitability for biomarker discovery is unexplored. EXPERIMENTAL DESIGN: We conducted a three-phase study. Phase 1: Aortas from angiotensin-II-infused apolipoprotein E deficient (ApoE(-/-) ) mice with and without AAA were assessed via iTRAQ and analyzed in silico to identify potential circulating markers. Microarray data from ApoE(-/-) mice and human patients were analyzed in parallel. Phase 2: Putative markers were compared between datasets to shortlist common candidates. Phase 3: The relationship of two shortlisted markers and AAA presence was assessed. RESULTS: iTRAQ identified eight proteins with biomarker potential. Microarray data identified 72 and 96 potential biomarkers from ApoE(-/-) mice and human patients, respectively. All three datasets suggested apolipoprotein C1 (ApoC1) as a marker for AAA; microarray data identified matrix metalloproteinase 9 (MMP9) as a second potential marker. Plasma ApoC1 and MMP9 concentrations positively correlated with AAA diameter in ApoE(-/-) mice. CONCLUSIONS AND CLINICAL RELEVANCE: ApoC1 may be a novel biomarker for AAA

Abdominal aortic aneurysm pathology and progress towards a medical therapy

Abdominal aortic aneurysm (AAA) is an important cause of mortality in older adults due to aortic rupture. Surgical repair (either by endovascular or open surgery) is the only treatment for AAA. However, large randomized controlled trials have demonstrated that elective repair of small (<55 mm) AAAs does not reduce all-cause mortality. Most AAAs detected through screening programs or incidental imaging are too small to warrant immediate surgical repair. Such patients are managed conservatively with repeated imaging to monitor AAA diameter. Nonetheless, 60–70% of AAAs managed in this way eventually grow to a size warranting elective surgery. Discovery of a drug therapy which effectively slows the growth of small AAAs has significant potential to improve patient welfare and reduce the number of individuals requiring elective surgery. This chapter reviews the current understanding of AAA pathogenesis gained through assessment of animal models and clinical samples. Previous AAA drug trials are also discussed. Finally, the challenges in developing AAA drugs are outlined