Cardiac emergencies: infective endocarditis, pericarditis, and myocarditis

Effect of promethazine on biofilms of gram-positive cocci associated with infectious endocarditis

This study evaluated the antimicrobial activity of promethazine against Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus mutans and its effect on the antimicrobial susceptibility of biofilms grown in vitro and ex vivo on porcine heart valves. Promethazine was evaluated alone and in combination with vancomycin and oxacillin against Staphylococcus spp. and vancomycin and ceftriaxone against S. mutans in planktonic form and biofilms grown in vitro and ex vivo. Promethazine minimum inhibitory concentration range was 24.4-95.31 μg/mL and minimum biofilm eradication concentration range was 781.25-3.125 μg/mL. Promethazine interacted synergistically with vancomycin, oxacillin and ceftriaxone against biofilms in vitro. Promethazine alone reduced (p < 0.05) the CFU-counts of biofilms grown on heart valves for Staphylococcus spp., but not for S. mutans, and increased (p < 0.05) the activity of vancomycin, oxacillin and ceftriaxone against biofilms of Gram-positive cocci grown ex vivo. These findings bring perspectives for repurposing promethazine as adjuvant in the treatment of infective endocarditis.

A Rare Case of Primary Purulent Pericarditis Caused by Streptococcus constellatus

Background: Bacteria-caused acute pericarditis is a very rare entity. It is usually associated with an underlying infection or compromised immune system. Primary purulent pericarditis in a previously healthy individual is highly unexpected; therefore, it is likely to have a delayed diagnosis and poor outcomes. Case: We report a case of an adult immunocompetent patient with primary bacterial pericarditis caused by a member of the commensal oral flora Streptococcus constellatus. The patient presented with septic shock and cardiac tamponade, and was further complicated with constrictive pericarditis, which was successfully treated with pericardiectomy. Conclusions: Bacterial pericarditis is a fulminant disease with a high mortality and complication rate. Fast recognition and prompt therapy are required to achieve a full recovery.

Cateslytin abrogates lipopolysaccharide-induced cardiomyocyte injury by reducing inflammation and oxidative stress through toll like receptor 4 interaction

Global public health is threatened by new pathogens, antimicrobial resistant microorganisms and a rapid decline of conventional antimicrobials efficacy. Thus, numerous medical procedures become life-threating. Sepsis can lead to tissue damage such as myocardium inflammation, associated with reduction of contractility and diastolic dysfunction, which may cause death. In this perspective, growing interest and attention are paid on host defence peptides considered as new potential antimicrobials. In the present study, we investigated the physiological and biochemical properties of Cateslytin (Ctl), an endogenous antimicrobial chromogranin A-derived peptide, in H9c2 cardiomyocytes exposed to lipopolysaccharide (LPS) infection. We showed that both Ctl (L and D) enantiomers, but not their scrambled counterparts, significantly increased cardiomyocytes viability following LPS, even if L-Ctl was effective at lower concentration (1 nM) compared to D-Ctl (10 nM). L-Ctl mitigated LPS-induced LDH release and oxidative stress, as visible by a reduction of MDA and protein carbonyl groups content, and by an increase of SOD activity. Molecular docking simulations strongly suggested that L-Ctl modulates TLR4 through a direct binding to the partner protein MD-2. Molecular analyses indicated that the protection mediated by L-Ctl against LPS-evoked sepsis targeted the TLR4/ERK/JNK/p38-MAPK pathway, regulating NFkB p65, NFkB p52 and COX2 expression and repressing the mRNA expression levels of the LPS-induced proinflammatory factors IL-1β, IL-6, TNF-α and NOS2. These findings indicate that Ctl could be considered as a possible candidate for the development of new antimicrobials strategies in the treatment of myocarditis. Interestingly, L-enantiomeric Ctl showed remarkable properties in strengthening the anti-inflammatory and anti-oxidant effects on cardiomyocytes.

Mini-review: from in vitro to ex vivo studies: an overview of alternative methods for the study of medical biofilms

Microbial biofilms are a natural adaptation of microorganisms, typically composed of multiple microbial species, exhibiting complex community organization and cooperation. Biofilm dynamics and their complex architecture are challenging for basic analyses, including the number of viable cells, biomass accumulation, biofilm morphology, among others. The methods used to study biofilms range from in vitro techniques to complex in vivo models. However, animal welfare has become a major concern, not only in society, but also in the academic and scientific field. Thus, the pursuit for alternatives to in vivo biofilm analyses presenting characteristics that mimic in vivo conditions has become essential. In this context, the present review proposes to provide an overview of strategies to study biofilms of medical interest, with emphasis on alternatives that approximate experimental conditions to host-associated environments, such as the use of medical devices as substrata for biofilm formation, microcosm and ex vivo models.

The effects of adding angiotensin receptor neprilysin inhibitors to usual care in patients with heart failure: a protocol for a systematic review of randomised clinical trials with meta-analysis and trial sequential analysis

BACKGROUND

Heart failure is a highly prevalent disease with a global prevalence of 37 million, and the prevalence is increasing. Patients with heart failure are at an increased risk of death and morbidity. Traditionally, patients with heart failure have been treated with a beta-blocker in addition to an inhibitor of the renin-angiotensin-aldosterone system. However, new drugs are currently being added to the recommended guideline therapy. The latest drug to be added combines inhibition of the renin-angiotensin-aldosterone system pathway with inhibiting the neprilysin enzyme and is therefore classified as an ARNI. Our objective is to identify the beneficial and harmful effects of ARNIs in the treatment of patient with heart failure.

METHODS

This protocol for a systematic review was undertaken using the recommendations of the Cochrane, the Preferred Report Items of Systematic reviews with Meta-Analysis Protocols, and the eight-step assessment procedure suggested by Jakobsen and colleagues. We plan to include all relevant randomised clinical trials assessing the use of ARNIs in the treatment of patients with heart failure. We will search the Cochrane Central Register of Controlled Trials (CENTRAL), Medical Literature Analysis and Retrieval System Online (MEDLINE), Excerpta Medica database (EMBASE), Latin American and Caribbean Health Sciences Literature (LILACS), Science Citation Index Expanded on Web of Science, Chinese Biomedical Literature Database (CBM), China National Knowledge Infrastructure (CNKI), Chinese Science Journal Database (VIP), and BIOSIS to identify relevant trials. We will also search for grey literature and unpublished trials. Extracted data will be analysed using Review Manager 5, STATA 5, and Trial Sequential Analysis. Our primary outcomes will be all-cause mortality and serious adverse events. We will create a 'Summary of Findings' table in which we will present our primary and secondary outcomes, and we will assess the quality of evidence using the GRADE assessment.

DISCUSSION

The present systematic review will have the potential to aid clinicians in decision-making and thereby, benefit patients with heart failure.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019129336.

Vitamin D receptor restricts T helper 2-biased inflammation in the heart

Background and aims

The aberrant immune responses play a critical role in the pathogenesis of myocarditis. Vitamin D receptor (VDR) has immune regulatory functions. This study aims to investigate the role of VDR in restricting the immune inflammation in the heart.

Methods and results

The human heart samples were obtained from the heart transplantation. T helper (Th)2 and Th1 responses in the heart tissue were characterized by histology and immune assay. VDR-/- mice and recombination activating gene 2-/- mice were used in the experiments to test the role of VDR in maintaining the homeostasis in the heart. The results showed that, besides tissue damage, lower expression of VDR, high frequency of Th2 cells and increase in Th2 cytokines in the hearts of patients with myocarditis at the end stage of heart failure. The spontaneous Th2-biased inflammation was observed in the hearts of VDR-/- mice. CD4+ T cells from the VDR-/- mouse hearts were at highly activating status. The naïve VDR-/- CD4+ T cells and naïve CD4+ T cells from human hearts with myocarditis were prone to differentiate into Th2 cells. VDR formed complexes with GATA3, the interleukin (IL)-4 transcription factor, to prevent the Il4 gene transcription. Transplantation with VDR-/-CD4+ T cells induced the Th2-biased inflammation in the hearts of Rag2-/- mice. Reconstitution of VDR in CD4+ T cells inhibited the Th2-biased inflammation in the heart.

Conclusions

VDR-deficiency contributes to the pathogenesis of myocarditis. To enhance the VDR expression in CD4+, T cells haves the therapeutic potential for the treatment of myocarditis.

18F-FDG-PET/CT Imaging to Diagnose Septic Emboli and Mycotic Aneurysms in Patients with Endocarditis and Cardiac Device Infections

PURPOSE OF REVIEW

This review analyzes recent studies evaluating the diagnostic value of ¹⁸F-FDG-PET/CT for the detection of peripheral emboli and secondary infectious foci in patients with infective endocarditis and cardiac device infections.

RECENT FINDINGS

Detection of extracardiac septic localizations in patients with infective endocarditis and cardiac device infections is crucial, as it may impact the diagnosis, prognosis, and therapeutic management. Recent literature substantiated the clinical usefulness of ¹⁸F-FDG-PET/CT in this setting. ¹⁸F-FDG-PET/CT has proven its high diagnostic value for the detection of peripheral emboli in patients with infective endocarditis and cardiac device infections, substantially affecting patients' outcome and treatment. A multimodal approach, combining the high sensitivity of ¹⁸F-FDG-PET/CT with morphological imaging seems promising.

The causative agents in infective endocarditis: a systematic review comprising 33,214 cases

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.