Characterisation of autophagy pathways in atherosclerosis

Atherosclerosis is an inflammatory disease of large to intermediate-sized arteries, characterised by retention of modified low-density lipoprotein within the vessel wall; this evokes an inflammatory response. Low-density lipoprotein carries lipids such as fatty acids, triglycerides and cholesterol, from the liver to peripheral tissues. The lipids carried by lipoproteins can be mobilised for metabolic processes, or if excessive, be stored in intracellular depots called lipid droplets. When imbalances in lipoprotein transport and/or cellular lipid metabolism occur, the risk for metabolic disorders, atherosclerosis and cardiovascular disease increases. Perilipins are lipid droplet-associated proteins, which regulate lipid mobilisation and metabolism from lipid droplets by allowing lipases access to the lipids within the lipid droplet. Macroautophagy, generally referred to as “autophagy”, regulates cholesterol metabolism in macrophage foam cells of atherosclerotic plaques. This is a parallel mechanism by which cells can mobilise lipids, distinct from the traditional dogma that cytosolic lipases mobilise intracellular lipid storages. Further, it contributes to the regulation of inflammation of atherosclerosis-afflicted vessels and it has been shown that ablation of core autophagy genes exacerbates atherosclerosis in murine disease. In this thesis we describe a protein variant in perilipin-2, which reduces plasma triglyceride levels, alters intracellular lipid metabolism and is protective of subclinical atherosclerosis. By adopting a molecular genetic approach, including a well-defined recruit-by-genotype protocol, we clearly demonstrate that perilipin-2 constitutes a hub between cholesterol metabolism and autophagy by fine-tuning liver-X-receptor activity. We also show that liver-X-receptor and autophagy are responsible for their reciprocal activation and that 27-hydroxycholesterol drives this feed-forward loop between liver-X-receptor activity autophagy – the mechanism by which the protein variant in perilipin-2 exerts its beneficial effects on subclinical atherosclerosis. Further we determine the presence of the autophagy-related proteins ATG16L1 and MAP1LC3A in human carotid atherosclerotic plaques where they are associated to plaque inflammation and vascular smooth muscle cell phenotypic switch, respectively. Ultimately, the presence of autophagy-related proteins in human carotid atherosclerotic plaques modulates plaque stability. Collectively, data presented herein, extend on the existing murine data and suggest that deregulated autophagy is a feature of human atherosclerosis. Treatment options targeting autophagy in the treatment of atherosclerosis are still hampered by specificity of treatment and timely intervention

Impact of a social marketing intervention on general practitioners’ antibiotic prescribing practices for acute respiratory tract complaints in Malta

Introduction: Antibiotics are commonly prescribed in primary care for acute respiratory tract complaints (aRTCs), often inappropriately. Social marketing interventions could improve prescribing in such settings. We evaluate the impact of a social marketing intervention on general practitioners’ (GPs’) antibiotic prescribing for aRTCs in Malta.Methods: Changes in GPs’ antibiotic prescribing were monitored over two surveillance periods between 2015 and 2018. Primary outcome: change in antibiotic prescription for aRTCs. Secondary outcomes: change in antibiotic prescription: (i) for immediate use, (ii) for delayed antibiotic prescription, (iii) by diagnosis, and (iv) by antibiotic class. Data were analysed using clustered analysis and interrupted time series analysis (ITSA).Results: Of 33 participating GPs, 18 successfully completed the study. Although clustered analyses showed a significant 3% decrease in overall antibiotic prescription (p = 0.024), ITSA showed no significant change overall (p = 0.264). Antibiotic prescription decreased significantly for the common cold (p < 0.001), otitis media (p = 0.044), and sinusitis (p = 0.004), but increased for pharyngitis (p = 0.015).Conclusions: The intervention resulted in modest improvements in GPs’ antibiotic prescribing. A more top-down approach will likely be required for future initiatives to be successful in this setting, focusing on diagnostic and prescribing support like rapid diagnostic testing, prescribing guidelines, and standardised delayed antibiotic prescriptions.peer-reviewe

Antibiotic prescribing for respiratory tract complaints in Malta : a 1 year repeated cross-sectional surveillance study

Objectives: To determine the 1 year antibiotic prescribing patterns by GPs for acute respiratory tract complaints (aRTCs) in Malta. Methods: In this repeated cross-sectional surveillance study, GPs collected data for patients seen for aRTCs during a designated 1 week period each month, between May 2015 and April 2016. GPs received three text reminders during surveillance weeks and were contacted by phone at most four times during the year. GPs also received 3 monthly individual- and aggregate-level feedback reports on their antibiotic prescribing patterns. Descriptive statistics were used to examine patient, consultation and clinical characteristics, and to describe GPs’ prescribing patterns. Results: Participating GPs (n = 33) registered 4641 patients with an aRTC, of whom 2122 (45.7%) received an antibiotic prescription. The majority (99.6%) of antibiotics prescribed were broad-spectrum and the most commonly prescribed antibiotics were macrolides (35.5%), followed by penicillins with a β-lactamase inhibitor (33.2%) and second-generation cephalosporins (14.2%). Specifically, co-amoxiclav (33.2%), clarithromycin (19.6%), azithromycin (15.1%) and cefuroxime axetil (10.9%) represented 78.8% of all antibiotics prescribed. Patients with tonsillar exudate (99.1%), purulent sputum (84%), otorrhoea (78%), tender cervical nodes (74.4%) and fever (73.1%) received most antibiotics. The diagnoses that received the highest proportion of antibiotic treatment were tonsillitis (96.3%), otitis media (92.5%) and bronchitis (87.5%). Wide variation in the choice of antibiotic class by diagnosis was observed. Conclusions: GP antibiotic prescribing in Malta is high. The abundant use of broad-spectrum antibiotics, particularly macrolides, is of particular concern and indicates that antibiotics are being used inappropriately. Efforts must be made to improve GP awareness of appropriate antibiotic prescribing.peer-reviewe

Factors associated with antibiotic prescribing in patients with acute respiratory tract complaints in Malta : a 1-year repeated cross-sectional surveillance study

Objective: To identify factors that influence general practitioners’ (GPs’) oral antibiotic prescribing for acute respiratory tract complaints (aRTCs) in Malta. Design: Repeated, cross-sectional surveillance. Setting: Maltese general practice; both public health centres and private GP clinics. Participants: 30 GPs registered on the Malta Medical Council’s Specialist Register and 3 GP trainees registered data of 4831 patients of all ages suffering from any aRTC. Data were collected monthly between May 2015 and April 2016 during predetermined 1-week periods. Outcome measures: The outcome of interest was antibiotic prescription (yes/no), defined as an oral antibiotic prescription issued for an aRTC during an in-person consultation, irrespective of the number of antibiotics given. The association between GP, practice and consultation-level factors, patient sociodemographic factors and patient health status factors, and antibiotic prescription was investigated. Results: The antibiotic prescription rate was 45.0%. Independent factors positively associated with antibiotic prescribing included female GP sex (OR 2.3, 95% CI 1.22 to 4.26), GP age with GPs ≥60 being the most likely (OR 34.7, 95% CI 14.14 to 84.98), patient age with patients ≥65 being the most likely (OR 2.3, 95% CI 1.71 to 3.18), number of signs and/or symptoms with patients having ≥4 being the most likely (OR 9.6, 95% CI 5.78 to 15.99), fever (OR 2.6, 95% CI 2.08 to 3.26), productive cough (OR 1.3, 95% CI 1.03 to 1.61), otalgia (OR 1.3, 95% CI 1.01 to 1.76), tender cervical nodes (OR 2.2, 95% CI 1.57 to 3.05), regular clients (OR 1.3, 95% CI 1.05 to 1.66), antibiotic requests (OR 4.8, 95% CI 2.52 to 8.99) and smoking (OR 1.4, 95% CI 1.13 to 1.71). Conversely, patients with non-productive cough (OR 0.3, 95% CI 0.26 to 0.41), sore throat (OR 0.6, 95% CI 0.53 to 0.78), rhinorrhoea (OR 0.3, 95% CI 0.23 to 0.36) or dyspnoea (OR 0.6, 95% CI 0.41 to 0.83) were less likely to receive an antibiotic prescription. Conclusion: Antibiotic prescribing for aRTCs was high and influenced by a number of factors. Potentially inappropriate prescribing in primary care can be addressed through multifaceted interventions addressing modifiable factors associated with prescription.peer-reviewe

Identification of a novel proinsulin-associated SNP and demonstration that proinsulin is unlikely to be a causal factor in subclinical vascular remodelling using Mendelian randomisation

Background and aims Increased proinsulin relative to insulin levels have been associated with subclinical atherosclerosis (measured by carotid intima-media thickness (cIMT)) and are predictive of future cardiovascular disease (CVD), independently of established risk factors. The mechanisms linking proinsulin to atherosclerosis and CVD are unclear. A genome-wide meta-analysis has identified nine loci associated with circulating proinsulin levels. Using proinsulin-associated SNPs, we set out to use a Mendelian randomisation approach to test the hypothesis that proinsulin plays a causal role in subclinical vascular remodelling. Methods We studied the high CVD-risk IMPROVE cohort (n = 3345), which has detailed biochemical phenotyping and repeated, state-of-the-art, high-resolution carotid ultrasound examinations. Genotyping was performed using Illumina Cardio-Metabo and Immuno arrays, which include reported proinsulin-associated loci. Participants with type 2 diabetes (n = 904) were omitted from the analysis. Linear regression was used to identify proinsulin-associated genetic variants. Results We identified a proinsulin locus on chromosome 15 (rs8029765) and replicated it in data from 20,003 additional individuals. An 11-SNP score, including the previously identified and the chromosome 15 proinsulin-associated loci, was significantly and negatively associated with baseline IMTmean and IMTmax (the primary cIMT phenotypes) but not with progression measures. However, MR-Eggers refuted any significant effect of the proinsulin-associated 11-SNP score, and a non-pleiotropic SNP score of three variants (including rs8029765) demonstrated no effect on baseline or progression cIMT measures. Conclusions We identified a novel proinsulin-associated locus and demonstrated that whilst proinsulin levels are associated with cIMT measures, proinsulin per se is unlikely to have a causative effect on cIMT

Impact of a Social Marketing Intervention on General Practitioners’ Antibiotic Prescribing Practices for Acute Respiratory Tract Complaints in Malta

Introduction: Antibiotics are commonly prescribed in primary care for acute respiratory tract complaints (aRTCs), often inappropriately. Social marketing interventions could improve prescribing in such settings. We evaluate the impact of a social marketing intervention on general practitioners’ (GPs’) antibiotic prescribing for aRTCs in Malta. Methods: Changes in GPs’ antibiotic prescribing were monitored over two surveillance periods between 2015 and 2018. Primary outcome: change in antibiotic prescription for aRTCs. Secondary outcomes: change in antibiotic prescription: (i) for immediate use, (ii) for delayed antibiotic prescription, (iii) by diagnosis, and (iv) by antibiotic class. Data were analysed using clustered analysis and interrupted time series analysis (ITSA). Results: Of 33 participating GPs, 18 successfully completed the study. Although clustered analyses showed a significant 3% decrease in overall antibiotic prescription (p = 0.024), ITSA showed no significant change overall (p = 0.264). Antibiotic prescription decreased significantly for the common cold (p &lt; 0.001), otitis media (p = 0.044), and sinusitis (p = 0.004), but increased for pharyngitis (p = 0.015). Conclusions: The intervention resulted in modest improvements in GPs’ antibiotic prescribing. A more top-down approach will likely be required for future initiatives to be successful in this setting, focusing on diagnostic and prescribing support like rapid diagnostic testing, prescribing guidelines, and standardised delayed antibiotic prescriptions

Lack of genetic susceptibility in takotsubo cardiomyopathy: a case-control study

Abstract Background Takotsubo cardiomyopathy (TCM), also known as “broken heart syndrome”, is a type of heart failure characterized by transient ventricular dysfunction in the absence of obstructive coronary lesions. Although associated with increased levels of catecholamines, pathophysiological mechanisms are unknown. Relapses and family heritability indicate a genetic predisposition. Several small studies have investigated associations between three different loci; the β1-adrenic receptor (ADRB1), G-protein-coupled receptor kinase 5 (GRK5), Bcl-associated athanogene 3 (BAG3) and TCM but no consensus has been reached. Methods Participants were recruited using the Swedish Coronary Angiography and Angioplasty Register (SCAAR). TCM patients without coronary artery disease (CAD)(n = 258) were identified and age- and sex-matched subjects with (n = 164) and without (n = 243) CAD were selected as controls. DNA was isolated from saliva and genotyped for candidate single nucleotide polymorphisms in the ADRB1, GRK5 and BAG3 genes. Allele frequencies and Odds Ratios (OR) with 95% Confidence Intervals (CI) for the investigated polymorphisms were compared, respectively calculated for TCM patients and controls. Results There were no differences in allele frequencies between TCM patients and controls. OR (CI) for TCM patients having at least one minor allele using controls as reference were 1.07 (0.75–1.55) for ADRB1, 0.45 (0.11–1.85) for GRK5 and 1.27 (0.74–2.19) for BAG3. Conclusion By genotyping a large takotsubo cohort, we demonstrate a lack of association between candidate SNPs in the ADRB1, GRK5 and BAG3 genes, earlier suggested to contribute to TCM. Our result indicates a need to expand the search for new genetic candidates contributing to TCM

Additional file 1: of Lack of genetic susceptibility in takotsubo cardiomyopathy: a case-control study

Questionnaire. Questionnaire, translated from Swedish to English, sent to patients and controls to recover medical history. (DOCX 12 kb

Additional file 2: of Lack of genetic susceptibility in takotsubo cardiomyopathy: a case-control study

Table. Allele frequencies. Chi square test of observed and expected allele frequencies. (DOCX 91 kb