Cardiovascular magnetic resonance (CMR) has become the primary tool for non-invasive assessment of myocardial inflammation in patients with suspected myocarditis. The International Consensus Group on CMR Diagnosis of Myocarditis was founded in 2006 to achieve consensus among CMR experts and develop recommendations on the current state-of-the-art use of CMR for myocarditis. The recommendations include indications for CMR in patients with suspected myocarditis, CMR protocol standards, terminology for reporting CMR findings, and diagnostic CMR criteria for myocarditis (“Lake Louise Criteria”).
Abstract-Inflammatory response and cytokine elaboration are particularly active after myocardial infarction and contribute to cardiac remodeling and eventual host outcome. The triggers of cytokine release in the acute postinfarction period include mechanical deformation, ischemic stimulus, reactive oxygen species (ROS), and cytokine selfamplification pathways. Acutely, the elaboration of tumor necrosis factor, IL-1 and IL-6, transforming growth factor families of cytokines, contribute to survival or deaths of myocytes, modulation of cardiac contractility, alterations of vascular endothelium, and recruitment of additional circulating cells of inflammation to the injured myocardium. This leads to further local oxidative stress and remodeling but also initiates the processes of wound healing. Chronically, sustained presence of cytokines leads to myocyte phenotype transition and activation of matrix metalloproteinases that modifies interstitial matrix, augmenting further the remodeling process. This in turn alters the local collagen composition and also the integrins that constitute the interface between myocytes and the matrix. These processes ultimately, when favorable, pave the way for angiogenesis and cellular regeneration. Thus, the insightful modulation of cytokines through current and future therapies could promote improved healing and cardiac remodeling postmyocardial infarction.
Using RNAi screening, proteomics, cell biological and mouse genetics approaches, we have identified a complex of nine proteins, seven of which are disrupted in human ciliopathies. A transmembrane component, TMEM231, localizes to the basal body before and independently of intraflagellar transport in a Septin 2 (Sept2)-regulated fashion. The localizations of TMEM231, B9D1 (B9 domain-containing protein 1) and CC2D2A (coiled-coil and C2 domain-containing protein 2A) at the transition zone are dependent on one another and on Sept2. Disruption of the complex in vitro causes a reduction in cilia formation and a loss of signalling receptors from the remaining cilia. Mouse knockouts of B9D1 and TMEM231 have identical defects in Sonic hedgehog (Shh) signalling and ciliogenesis. Strikingly, disruption of the complex increases the rate of diffusion into the ciliary membrane and the amount of plasma-membrane protein in the cilia. The complex that we have described is essential for normal cilia function and acts as a diffusion barrier to maintain the cilia membrane as a compartmentalized signalling organelle.
The regulation of tyrosine phosphorylation and associated signalling through antigen, growth-factor and cytokine receptors is mediated by the reciprocal activities of protein tyrosine kinases and protein tyrosine phosphatases (PTPases). The transmembrane PTPase CD45 is a key regulator of antigen receptor signalling in T and B cells. Src-family kinases have been identified as primary molecular targets for CD45 (ref. 4). However, CD45 is highly expressed in all haematopoietic lineages at all stages of development, indicating that CD45 could regulate other cell types and might act on additional substrates. Here we show that CD45 suppresses JAK (Janus kinase) kinases and negatively regulates cytokine receptor signalling. Targeted disruption of the cd45 gene leads to enhanced cytokine and interferon-receptor-mediated activation of JAKs and STAT (signal transducer and activators of transcription) proteins. In vitro, CD45 directly dephosphorylates and binds to JAKs. Functionally, CD45 negatively regulates interleukin-3-mediated cellular proliferation, erythropoietin-dependent haematopoieisis and antiviral responses in vitro and in vivo. Our data identify an unexpected and novel function for CD45 as a haematopoietic JAK phosphatase that negatively regulates cytokine receptor signalling.
Human inner ear tissue derived from pluripotent stem cells could provide a powerful platform for drug discovery or a source of sound-or motion-sensing cells for patients with hearing loss or balance dysfunction. Here we report a method for differentiating human pluripotent stem cells to inner ear organoids that harbor functional hair cells. Using a three-dimensional culture system, we modulate TGF, BMP, FGF, and Wnt signaling to generate multiple otic vesicle-like structures from a single stem-cell aggregate. Over two months, the vesicles develop into inner ear organoids with sensory epithelia that are innervated by sensory neurons. Additionally, using CRISPR/Cas9, we generate an ATOH1-2A-eGFP cell line to detect hair cell induction and demonstrate that derived hair cells exhibit electrophysiological properties similar to those of native sensory hair cells. Our culture system will be useful for elucidating mechanisms of human inner ear development and testing potential inner ear therapies.The human inner ear contains ∼75,000 sensory hair cells that detect sound and movement via mechanosensitive stereocilia bundles 1,2 . Genetic mutations or environmental insults, such as loud noises and ototoxic drugs, can cause irreparable damage to these hair cells, Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:
Background-Studies in experimental models and preliminary clinical experience suggested a possible therapeutic role for the soluble tumor necrosis factor antagonist etanercept in heart failure. Methods and Results-Patients with New York Heart Association class II to IV chronic heart failure and a left ventricular ejection fraction Յ0.30 were enrolled in 2 clinical trials that differed only in the doses of etanercept used. In RECOVER, patients received placebo (nϭ373) or subcutaneous etanercept in doses of 25 mg every week (nϭ375) or 25 mg twice per week (nϭ375). In RENAISSANCE, patients received placebo (nϭ309), etanercept 25 mg twice per week (nϭ308), or etanercept 25 mg 3 times per week (nϭ308). The primary end point of each individual trial was clinical status at 24 weeks. Analysis of the effect of the 2 higher doses of etanercept on the combined outcome of death or hospitalization due to chronic heart failure from the 2 studies was also planned (RENEWAL). On the basis of prespecified stopping rules, both trials were terminated prematurely owing to lack of benefit. Etanercept had no effect on clinical status in RENAISSANCE (Pϭ0.17) or RECOVER (Pϭ0.34) and had no effect on the death or chronic heart failure hospitalization end point in RENEWAL (etanercept to placebo relative riskϭ1.1, 95% CI 0.91 to 1.33, Pϭ0.33). Conclusions-The results of RENEWAL rule out a clinically relevant benefit of etanercept on the rate of death or hospitalization due to chronic heart failure.
BACKGROUND Peripartum cardiomyopathy shares some clinical features with idiopathic dilated cardiomyopathy, a disorder caused by mutations in more than 40 genes, including TTN, which encodes the sarcomere protein titin. METHODS In 172 women with peripartum cardiomyopathy, we sequenced 43 genes with variants that have been associated with dilated cardiomyopathy. We compared the prevalence of different variant types (nonsense, frameshift, and splicing) in these women with the prevalence of such variants in persons with dilated cardiomyopathy and with population controls. RESULTS We identified 26 distinct, rare truncating variants in eight genes among women with peripartum cardiomyopathy. The prevalence of truncating variants (26 in 172 [15%]) was significantly higher than that in a reference population of 60,706 persons (4.7%, P = 1.3×10−7) but was similar to that in a cohort of patients with dilated cardiomyopathy (55 of 332 patients [17%], P = 0.81). Two thirds of identified truncating variants were in TTN, as seen in 10% of the patients and in 1.4% of the reference population (P = 2.7×10−10); almost all TTN variants were located in the titin A-band. Seven of the TTN truncating variants were previously reported in patients with idiopathic dilated cardiomyopathy. In a clinically well-characterized cohort of 83 women with peripartum cardiomyopathy, the presence of TTN truncating variants was significantly correlated with a lower ejection fraction at 1-year follow-up (P = 0.005). CONCLUSIONS The distribution of truncating variants in a large series of women with peripartum cardiomyopathy was remarkably similar to that found in patients with idiopathic dilated cardiomyopathy. TTN truncating variants were the most prevalent genetic predisposition in each disorder.
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