Clinical and Genetic Screening for Hypertrophic Cardiomyopathy in Paediatric Relatives: Changing Paradigms in Clinical Practice

Hypertrophic cardiomyopathy (HCM) is an important cause of morbidity and mortality in children. While the aetiology is heterogeneous, most cases are caused by variants in the genes encoding components of the cardiac sarcomere, which are inherited as an autosomal dominant trait. In recent years, there has been a paradigm shift in the role of clinical screening and predictive genetic testing in children with a first-degree relative with HCM, with the recognition that phenotypic expression can, and often does, manifest in young children and that familial disease in the paediatric age group may not be benign. The care of the child and family affected by HCM relies on a multidisciplinary team, with a key role for genomics. This review article summarises current evidence in clinical and genetic screening for hypertrophic cardiomyopathy in paediatric relatives and highlights aspects that remain to be resolved

Heart valve prostheses in pregnancy: Outcomes for women and their babies

Background: As the prognosis of women with prosthetic heart valves improves more of these individuals are contemplating and undertaking pregnancy. Accurate knowledge of perinatal outcomes is essential, assisting counselling and guiding care. The aim of this study was to assess outcomes in a contemporary population of women with heart valve prostheses undertaking pregnancy, and to compare outcomes for women with mechanical and bioprosthetic prostheses. Method and results: Longitudinally-linked population health datasets containing birth and hospital admissions data were obtained for all women giving birth in New South Wales, Australia, 2000-2011. This included information identifying presence of maternal prosthetic heart valve. Cardiovascular and birth outcomes were evaluated. Among 1 144 156 pregnancies, 136 involved women with a heart valve prosthesis (1 in 10 000). No maternal mortality was seen among these women, although the relative risk for an adverse event was higher than the general population, including severe maternal morbidity (13.9% v. 1.4%, RR=9.96, 95% CI 6.32-15.7), major maternal cardiovascular event (4.4% v. 0.1%, RR 34.6, 95% CI 14.6-81.6), preterm birth (18.3% v. 6.6%, RR=2.77, 95% CI 1.88-4.07) and small-for-gestational-age infants (19.3% v. 9.5%, RR=2.12, 95% CI 1.47-3.06). There was a trend towards increased maternal and perinatal morbidity in women with a mechanical valve compared to bioprosthetic. Conclusions: Pregnancies in women with a prosthetic heart valve demonstrate an increased risk of an adverse outcome, for both mothers and babies, compared with pregnancies in the absence of heart valve prostheses. In this contemporary population, the risk was lower than previously reported.NHMRC 1001066, NHMRC 1021025, NHMRC 1062262, ARC FT120100069, Australian Heart Foundatio

Heart valve prostheses in pregnancy: Outcomes for women and their babies

Background: As the prognosis of women with prosthetic heart valves improves more of these individuals are contemplating and undertaking pregnancy. Accurate knowledge of perinatal outcomes is essential, assisting counselling and guiding care. The aim of this study was to assess outcomes in a contemporary population of women with heart valve prostheses undertaking pregnancy, and to compare outcomes for women with mechanical and bioprosthetic prostheses. Method and results: Longitudinally-linked population health datasets containing birth and hospital admissions data were obtained for all women giving birth in New South Wales, Australia, 2000-2011. This included information identifying presence of maternal prosthetic heart valve. Cardiovascular and birth outcomes were evaluated. Among 1 144 156 pregnancies, 136 involved women with a heart valve prosthesis (1 in 10 000). No maternal mortality was seen among these women, although the relative risk for an adverse event was higher than the general population, including severe maternal morbidity (13.9% v. 1.4%, RR=9.96, 95% CI 6.32-15.7), major maternal cardiovascular event (4.4% v. 0.1%, RR 34.6, 95% CI 14.6-81.6), preterm birth (18.3% v. 6.6%, RR=2.77, 95% CI 1.88-4.07) and small-for-gestational-age infants (19.3% v. 9.5%, RR=2.12, 95% CI 1.47-3.06). There was a trend towards increased maternal and perinatal morbidity in women with a mechanical valve compared to bioprosthetic. Conclusions: Pregnancies in women with a prosthetic heart valve demonstrate an increased risk of an adverse outcome, for both mothers and babies, compared with pregnancies in the absence of heart valve prostheses. In this contemporary population, the risk was lower than previously reported.NHMRC 1001066, NHMRC 1021025, NHMRC 1062262, ARC FT120100069, Australian Heart Foundatio

Prosthetic heart valves in pregnancy, outcomes for women and their babies: A systematic review and meta-analysis

Background Historically, pregnancies among women with prosthetic heart valves have been associated with an increased incidence of adverse outcomes. While there have been advances in prosthetic heart valve design, obstetric and medical care, subsequent impact on incidence of adverse outcomes during pregnancy has not been quantified. Objectives To assess the risk of adverse pregnancy outcomes among women with a prosthetic heart valve(s) in the contemporary setting. Search Strategy Electronic literature search of Medline, The Cochrane Library, CINAHL (Cumulative Index to Nursing and Allied Health Literature) and Embase to find recent studies. Selection Criteria Studies of pregnant women with heart valve prostheses including trials, cohort studies and unselected case series. Data Collection and Analysis Absolute risks and 95% confidence intervals for pregnancy outcomes were calculated using either a random effects model or the logit transformation of total events and participants (the latter method when multiple studies had event counts of zero). Main Results Eleven studies capturing 499 pregnancies among women with heart valve prostheses were eligible for inclusion. Pooled maternal mortality rate was 0.8/100 pregnancies (95% CI 0.3-2.1), pregnancy loss rate 32.1/100 pregnancies (95% CI 28.1-36.3) and perinatal mortality rate 4.7/100 births (95% CI 2.7-7.9). Conclusions Women with heart valve prostheses experienced higher rates of adverse outcomes then would be expected in a general obstetric population, however lower than previously reported. Multidisciplinary pre-pregnancy counselling and vigilant cardiac and obstetric surveillance throughout the perinatal period remains warranted for these women and their infantsNHMRC 1001066, NHMRC 1021025, NHMRC 1062262, ARC FT120100069 and Australian Heart Foundatio

DNA Methylation and Transcription Patterns in Intestinal Epithelial Cells From Pediatric Patients With Inflammatory Bowel Diseases Differentiate Disease Subtypes and Associate With Outcome.

BACKGROUND & AIMS: We analyzed DNA methylation patterns and transcriptomes of primary intestinal epithelial cells (IEC) of children newly diagnosed with inflammatory bowel diseases (IBD) to learn more about pathogenesis. METHODS: We obtained mucosal biopsies (N = 236) collected from terminal ileum and ascending and sigmoid colons of children (median age 13 years) newly diagnosed with IBD (43 with Crohn's disease [CD], 23 with ulcerative colitis [UC]), and 30 children without IBD (controls). Patients were recruited and managed at a hospital in the United Kingdom from 2013 through 2016. We also obtained biopsies collected at later stages from a subset of patients. IECs were purified and analyzed for genome-wide DNA methylation patterns and gene expression profiles. Adjacent microbiota were isolated from biopsies and analyzed by 16S gene sequencing. We generated intestinal organoid cultures from a subset of samples and genome-wide DNA methylation analysis was performed. RESULTS: We found gut segment-specific differences in DNA methylation and transcription profiles of IECs from children with IBD vs controls; some were independent of mucosal inflammation. Changes in gut microbiota between IBD and control groups were not as large and were difficult to assess because of large amounts of intra-individual variation. Only IECs from patients with CD had changes in DNA methylation and transcription patterns in terminal ileum epithelium, compared with controls. Colon epithelium from patients with CD and from patients with ulcerative colitis had distinct changes in DNA methylation and transcription patterns, compared with controls. In IECs from patients with IBD, changes in DNA methylation, compared with controls, were stable over time and were partially retained in ex-vivo organoid cultures. Statistical analyses of epithelial cell profiles allowed us to distinguish children with CD or UC from controls; profiles correlated with disease outcome parameters, such as the requirement for treatment with biologic agents. CONCLUSIONS: We identified specific changes in DNA methylation and transcriptome patterns in IECs from pediatric patients with IBD compared with controls. These data indicate that IECs undergo changes during IBD development and could be involved in pathogenesis. Further analyses of primary IECs from patients with IBD could improve our understanding of the large variations in disease progression and outcomes

Insight into cross-talk between intra-amoebal pathogens

Abstract: Background: Amoebae are phagocytic protists where genetic exchanges might take place between amoeba-resistant bacteria. These amoebal pathogens are able to escape the phagocytic behaviour of their host. They belong to different bacterial phyla and often show a larger genome size than human-infecting pathogens. This characteristic is proposed to be the result of frequent gene exchanges with other bacteria that share a sympatric lifestyle and contrasts with the genome reduction observed among strict human pathogens.Results: We sequenced the genome of a new amoebal pathogen, Legionella drancourtii, and compared its gene content to that of a Chlamydia-related bacterium, Parachlamydia acanthamoebae. Phylogenetic reconstructions identified seven potential horizontal gene transfers (HGTs) between the two amoeba-resistant bacteria, including a complete operon of four genes that encodes an ABC-type transporter. These comparisons pinpointed potential cases of gene exchange between P. acanthamoebae and Legionella pneumophila, as well as gene exchanges between other members of the Legionellales and Chlamydiales orders. Moreover, nine cases represent possible HGTs between representatives from the Legionellales or Chlamydiales and members of the Rickettsiales order.Conclusions: This study identifies numerous gene exchanges between intracellular Legionellales and Chlamydiales bacteria, which could preferentially occur within common inclusions in their amoebal hosts. Therefore it contributes to improve our knowledge on the intra-amoebal gene properties associated to their specific lifestyle

Establishing What Constitutes a Healthy Human Gut Microbiome: State of the Science, Regulatory Considerations, and Future Directions.

On December 17, 2018, the North American branch of the International Life Sciences Institute (ILSI North America) convened a workshop "Can We Begin to Define a Healthy Gut Microbiome Through Quantifiable Characteristics?" with >40 invited academic, government, and industry experts in Washington, DC. The workshop objectives were to 1) develop a collective expert assessment of the state of the evidence on the human gut microbiome and associated human health benefits, 2) see if there was sufficient evidence to establish measurable gut microbiome characteristics that could serve as indicators of "health," 3) identify short- and long-term research needs to fully characterize healthy gut microbiome-host relationships, and 4) publish the findings. Conclusions were as follows: 1) mechanistic links of specific changes in gut microbiome structure with function or markers of human health are not yet established; 2) it is not established if dysbiosis is a cause, consequence, or both of changes in human gut epithelial function and disease; 3) microbiome communities are highly individualized, show a high degree of interindividual variation to perturbation, and tend to be stable over years; 4) the complexity of microbiome-host interactions requires a comprehensive, multidisciplinary research agenda to elucidate relationships between gut microbiome and host health; 5) biomarkers and/or surrogate indicators of host function and pathogenic processes based on the microbiome need to be determined and validated, along with normal ranges, using approaches similar to those used to establish biomarkers and/or surrogate indicators based on host metabolic phenotypes; 6) future studies measuring responses to an exposure or intervention need to combine validated microbiome-related biomarkers and/or surrogate indicators with multiomics characterization of the microbiome; and 7) because static genetic sampling misses important short- and long-term microbiome-related dynamic changes to host health, future studies must be powered to account for inter- and intraindividual variation and should use repeated measures within individuals

Genomic attributes of airway commensal bacteria and mucosa

Microbial communities at the airway mucosal barrier are conserved and highly ordered, in likelihood reflecting co-evolution with human host factors. Freed of selection to digest nutrients, the airway microbiome underpins cognate management of mucosal immunity and pathogen resistance. We show here the initial results of systematic culture and whole-genome sequencing of the thoracic airway bacteria, identifying 52 novel species amongst 126 organisms that constitute 75% of commensals typically present in heathy individuals. Clinically relevant genes encode antimicrobial synthesis, adhesion and biofilm formation, immune modulation, iron utilisation, nitrous oxide (NO) metabolism and sphingolipid signalling. Using whole-genome content we identify dysbiotic features that may influence asthma and chronic obstructive pulmonary disease. We match isolate gene content to transcripts and metabolites expressed late in airway epithelial differentiation, identifying pathways to sustain host interactions with microbiota. Our results provide a systematic basis for decrypting interactions between commensals, pathogens, and mucosa in lung diseases of global significance

A Role for TLR4 in Clostridium difficile Infection and the Recognition of Surface Layer Proteins

Clostridium difficile is the etiological agent of antibiotic-associated diarrhoea (AAD) and pseudomembranous colitis in humans. The role of the surface layer proteins (SLPs) in this disease has not yet been fully explored. The aim of this study was to investigate a role for SLPs in the recognition of C. difficile and the subsequent activation of the immune system. Bone marrow derived dendritic cells (DCs) exposed to SLPs were assessed for production of inflammatory cytokines, expression of cell surface markers and their ability to generate T helper (Th) cell responses. DCs isolated from C3H/HeN and C3H/HeJ mice were used in order to examine whether SLPs are recognised by TLR4. The role of TLR4 in infection was examined in TLR4-deficient mice. SLPs induced maturation of DCs characterised by production of IL-12, TNFα and IL-10 and expression of MHC class II, CD40, CD80 and CD86. Furthermore, SLP-activated DCs generated Th cells producing IFNγ and IL-17. SLPs were unable to activate DCs isolated from TLR4-mutant C3H/HeJ mice and failed to induce a subsequent Th cell response. TLR4−/− and Myd88−/−, but not TRIF−/− mice were more susceptible than wild-type mice to C. difficile infection. Furthermore, SLPs activated NFκB, but not IRF3, downstream of TLR4. Our results indicate that SLPs isolated from C. difficile can activate innate and adaptive immunity and that these effects are mediated by TLR4, with TLR4 having a functional role in experimental C. difficile infection. This suggests an important role for SLPs in the recognition of C. difficile by the immune system