Aging-related cellular and molecular processes including low-grade inflammation are major players in the pathogenesis of cardiovascular disease (CVD) and Alzheimer's disease (AD). Epidemiological studies report an independent interaction between the development of dementia and the incidence of CVD in several populations, suggesting the presence of overlapping molecular mechanisms. Accumulating experimental and clinical evidence suggests that amyloid-beta (Aβ) peptides may function as a link among aging, CVD, and AD. Aging-related vascular and cardiac deposition of Αβ induces tissue inflammation and organ dysfunction, both important components of the Alzheimer's disease amyloid hypothesis. In this review, the authors describe the determinants of Aβ metabolism, summarize the effects of Aβ on atherothrombosis and cardiac dysfunction, discuss the clinical value of Αβ1-40 in CVD prognosis and patient risk stratification, and present the therapeutic interventions that may alter Aβ metabolism in humans.
11 May 2016 in European Journal of Clinical Microbiology & Infectious Diseases
Infective endocarditis (IE) incidence remains high with considerable fatality rates; guidelines for prophylaxis against IE are currently under review in some settings which highlights the importance of maintaining up-to-date epidemiological estimates about the most common microbial causes. The objective of this systematic review, following PRISMA guidelines, was to identify the most common microbial causes of IE in recent years. Medline was searched from January 1, 2003 to March 31, 2013 for all articles containing the term "infective endocarditis". All relevant studies reporting diagnostic results were included. Special patient subpopulations were assessed separately. A total of 105 studies were included, from 36 countries, with available data on a total of 33,214 cases. Staphylococcus aureus was found to be the most common microorganism, being the most frequent in 54.3 % of studies (N = 57) (and in 55.4 % of studies using Duke's criteria for diagnosis [N = 51]). Viridans group streptococci (VGS), coagulase-negative staphylococci (CoNS), Enterococcus spp and Streptococcus bovis were among the most common causes. S. aureus was the most common pathogen in almost all population subgroups; however, this was not the case in patients with implantable devices, prosthetic valves, or immunocompromised non-HIV, as well as in the sub-group from Asia, emphasizing that a global one-size-fits-all approach to the management of suspected IE is not appropriate. This review provides an evidence-based map of the most common causative agents of IE, highlighting S. aureus as the leading cause in the 21st century. The changing epidemiology of IE in some patient sub-groups in the last decade and the very high number of microbiologically undiagnosed cases (26.6 %) suggest the need to revisit IE prophylaxis and diagnostic strategies.
The DNA damage response and repair (DDR/R) network, a sum of hierarchically structured signaling pathways that recognize and repair DNA damage, and the immune response to endogenous and/or exogenous threats, act synergistically to enhance cellular defense. On the other hand, a deregulated interplay between these systems underlines inflammatory diseases including malignancies and chronic systemic autoimmune diseases, such as systemic lupus erythematosus, systemic sclerosis, and rheumatoid arthritis. Patients with these diseases are characterized by aberrant immune response to self-antigens with widespread production of autoantibodies and multiple-tissue injury, as well as by the presence of increased oxidative stress. Recent data demonstrate accumulation of endogenous DNA damage in peripheral blood mononuclear cells from these patients, which is related to (a) augmented DNA damage formation, at least partly due to the induction of oxidative stress, and (b) epigenetically regulated functional abnormalities of fundamental DNA repair mechanisms. Because endogenous DNA damage accumulation has serious consequences for cellular health, including genomic instability and enhancement of an aberrant immune response, these results can be exploited for understanding pathogenesis and progression of systemic autoimmune diseases, as well as for the development of new treatments.
Adenosine-to-inosine (A-to-I) RNA editing of Alu retroelements is a primate-specific mechanism mediated by adenosine deaminases acting on RNA (ADARs) that diversifies transcriptome by changing selected nucleotides in RNA molecules. We tested the hypothesis that A-to-I RNA editing is altered in rheumatoid arthritis (RA). Synovium expression analysis of ADAR1 was investigated in 152 RA patients and 50 controls. Peripheral blood mononuclear cells derived from 14 healthy subjects and 19 patients with active RA at baseline and after 12-week treatment were examined for ADAR1p150 and ADAR1p110 isoform expression by RT-qPCR. RNA editing activity was analysed by AluSx+ Sanger-sequencing of cathepsin S, an extracellular matrix degradation enzyme involved in antigen presentation. ADAR1 was significantly over-expressed in RA synovium regardless of disease duration. Similarly, ADAR1p150 isoform expression was significantly increased in the blood of active RA patients. Individual nucleotide analysis revealed that A-to-I RNA editing rate was also significantly increased in RA patients. Both baseline ADAR1p150 expression and individual adenosine RNA editing rate of cathepsin S AluSx+ decreased after treatment only in those patients with good clinical response. Upregulation of the expression and/or activity of the RNA editing machinery were associated with a higher expression of edited Alu-enriched genes including cathepsin S and TNF receptor-associated factors 1,2,3 and 5. A previously unrecognized regulation and role of ADAR1p150-mediated A-to-I RNA editing in post-transcriptional control in RA underpins therapeutic response and fuels inflammatory gene expression, thus representing an interesting therapeutic target.
20 September 2018 in Antioxidants & Redox Signaling
Significance: Adenosine deamination in transcriptome results in the formation of inosine, a process that is called A-to-I RNA editing. Adenosine deamination is one of the more than 140 described RNA modifications. A-to-I RNA editing is catalyzed by adenosine deaminase acting on RNA (ADAR) enzymes and is essential for life. Recent Advances: Accumulating evidence supports a critical role of RNA editing in all aspects of RNA metabolism, including mRNA stability, splicing, nuclear export, and localization, as well as in recoding of proteins. These advances have significantly enhanced the understanding of mechanisms involved in development and in homeostasis. Furthermore, recent studies have indicated that RNA editing may be critically involved in cancer, aging, neurological, autoimmune, or cardiovascular diseases. Critical Issues: This review summarizes recent and significant achievements in the field of A-to-I RNA editing and discusses the importance and translational value of this RNA modification for gene expression, cellular, and organ function, as well as for disease development. Future Directions: Elucidation of the exact RNA editing-dependent mechanisms in a single-nucleotide level may pave the path toward the development of novel therapeutic strategies focusing on modulation of ADAR function in the disease context. Antioxid. Redox Signal. 00, 000–000.
The novel coronavirus disease (COVID-19) pandemic has already caused more than 300,000 deaths worldwide. Several studies have elucidated the central role of cardiovascular complications in the disease course. Herein, we provide a concise review of current knowledge regarding the involvement of cardiovascular system in the pathogenesis and prognosis of COVID-19. We summarize data from 21 studies involving in total more than 21,000 patients from Asia, Europe and the USA indicating that severe disease is associated with the presence of myocardial injury, heart failure and arrhythmias. Additionally, we present the clinical and laboratory differences between recovered and deceased patients highlighting the importance of cardiac manifestations. For the infected patients, underlying cardiovascular comorbidities and especially existing cardiovascular disease seem to predispose to the development of cardiovascular complications, which are in turn associated with higher mortality rates. We provide mechanistic insights into the underlying mechanisms including direct myocardial damage by the virus and the consequences of the hyperinflammatory syndrome developed later in the disease course. Finally, we summarize current knowledge on therapeutic modalities and recommendations by scientific societies and experts regarding the cardiovascular management of COVID-19 patients.