Abstract Background Brugada syndrome (BrS), a disorder associated with characteristic electrocardiogram precordial ST-segment elevation, predisposes afflicted patients to ventricular fibrillation and ...sudden cardiac death. Despite marked achievements in outlining the organ level pathophysiology of the disorder, the understanding of human cellular phenotype has lagged due to a lack of adequate human cellular models of the disorder. Objectives The objective of this study was to examine single cell mechanism of Brugada syndrome using induced pluripotent stem cell–derived cardiomyocytes (iPSC-CMs). Methods This study recruited 2 patients with type 1 BrS carrying 2 different sodium voltage-gated channel alpha subunit 5 variants as well as 2 healthy control subjects. We generated iPSCs from their skin fibroblasts by using integration-free Sendai virus. We used directed differentiation to create purified populations of iPSC-CMs. Results BrS iPSC-CMs showed reductions in inward sodium current density and reduced maximal upstroke velocity of action potential compared with healthy control iPSC-CMs. Furthermore, BrS iPSC-CMs demonstrated increased burden of triggered activity, abnormal calcium (Ca2+ ) transients, and beating interval variation. Correction of the causative variant by genome editing was performed, and resultant iPSC-CMs showed resolution of triggered activity and abnormal Ca2+ transients. Gene expression profiling of iPSC-CMs showed clustering of BrS compared with control subjects. Furthermore, BrS iPSC-CM gene expression correlated with gene expression from BrS human cardiac tissue gene expression. Conclusions Patient-specific iPSC-CMs were able to recapitulate single-cell phenotype features of BrS, including blunted inward sodium current, increased triggered activity, and abnormal Ca2+ handling. This novel human cellular model creates future opportunities to further elucidate the cellular disease mechanism and identify novel therapeutic targets.
The synthesis and X‐ray structure of a new manganese(V) mesitylimido complex with a tetraamido macrocyclic ligand (TAML), MnV(TAML)(N‐Mes)− (1), are reported. Compound 1 is oxidized by ...(p‐BrC6H4)3N+.SbCl6− and the resulting MnVI species readily undergoes H‐atom transfer and nitrene transfer reactions.
A rare MnVI: The synthesis and X‐ray structure of a new MnV mesitylimido(N‐Mes) complex with a tetraamido macrocyclic ligand (TAML), MnV(TAML)(N‐Mes)−, are reported. Upon one‐electron oxidation, a reactive species, MnVI(TAML)(N‐Mes) (2, see graphic), was generated; this species readily undergoes H‐atom transfer and nitrene transfer reactions.
The Human Microbiome Project has prompted unprecedented advancement in microbiome science. Personalized microbiome modulation with precision (PMMP) is one of the emerging yet challenging fields in ...microbiome research. Carbohydrate-based prebiotics (CBPs) have been shown to modulate the gut microbiome to various extents according to different structural characteristics, such as degree of polymerization, branching, glycosidic linkage, monosaccharide profile, and chemical modification. Subsequently, a targeted modulation of the microbiome might be achieved by using CBPs with a specific structure. A multidimensional database can be established based on the structure–microbiome and structure–microbial-marker relationships. Such relationships could facilitate the development of synbiotics and PMMP.
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•Presence of diurnal rhythmicity is observed in both core and peripheral tissues.•Weekly shifted light-dark cycle can lead to circadian misalignment.•Beta-glucan and inulin modulate ...expression and phase of circadian clock genes.•Beta-glucan and inulin supplementation alleviate circadian desynchrony.
Circadian rhythm governs multiple behavioural and physiological processes and its disruption is closely associated with various pathological conditions. In this study, the effects of dietary intervention by prebiotics including beta-glucan and inulin on attenuating circadian desynchrony in C57BL/6J mice subjected to weekly shifted light–dark cycle under a high fat diet was investigated. Using RT-qPCR and rhythmicity analysis, our study revealed that beta-glucan (0.2 g/day) and inulin (0.2 g/day) modulated the expression and phase of circadian-clock genes, explicitly reversed the phase delay of Period 1 and Period 3 in the hypothalamus, and reversed the phase delay of Period 2 in the liver of the mice. In the shifted mouse group, inulin also exhibited its reversal effects on the phase advance of Brain and muscle-Arnt-like 1 in the hypothalamus. These findings indicated that prebiotic supplementation can be a novel dietary approach for attenuating circadian misalignment.
The long QT syndrome (LQTS) is an arrhythmogenic disorder of QT interval prolongation that predisposes patients to life-threatening ventricular arrhythmias such as Torsades de pointes and sudden ...cardiac death. Clinical genetic testing has emerged as the standard of care to identify genetic variants in patients suspected of having LQTS. However, these results are often confounded by the discovery of variants of uncertain significance (VUS), for which there is insufficient evidence of pathogenicity.
The purpose of this study was to demonstrate that genome editing of patient-specific induced pluripotent stem cells (iPSCs) can be a valuable approach to delineate the pathogenicity of VUS in cardiac channelopathy.
Peripheral blood mononuclear cells were isolated from a carrier with a novel missense variant (T983I) in the KCNH2 (LQT2) gene and an unrelated healthy control subject. iPSCs were generated using an integration-free Sendai virus and differentiated to iPSC-derived cardiomyocytes (CMs).
Whole-cell patch clamp recordings revealed significant prolongation of the action potential duration (APD) and reduced rapidly activating delayed rectifier K+ current (IKr) density in VUS iPSC-CMs compared with healthy control iPSC-CMs. ICA-105574, a potent IKr activator, enhanced IKr magnitude and restored normal action potential duration in VUS iPSC-CMs. Notably, VUS iPSC-CMs exhibited greater propensity to proarrhythmia than healthy control cells in response to high-risk torsadogenic drugs (dofetilide, ibutilide, and azimilide), suggesting a compromised repolarization reserve. Finally, the selective correction of the causal variant in iPSC-CMs using CRISPR/Cas9 gene editing (isogenic control) normalized the aberrant cellular phenotype, whereas the introduction of the homozygous variant in healthy control cells recapitulated hallmark features of the LQTS disorder.
The results suggest that the KCNH2T983I VUS may be classified as potentially pathogenic.
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BACKGROUND:The progression toward low-cost and rapid next-generation sequencing has uncovered a multitude of variants of uncertain significance (VUS) in both patients and asymptomatic “healthy” ...individuals. A VUS is a rare or novel variant for which disease pathogenicity has not been conclusively demonstrated or excluded, and thus cannot be definitively annotated. VUS, therefore, pose critical clinical interpretation and risk-assessment challenges, and new methods are urgently needed to better characterize their pathogenicity.
METHODS:To address this challenge and showcase the uncertainty surrounding genomic variant interpretation, we recruited a “healthy” asymptomatic individual, lacking cardiac-disease clinical history, carrying a hypertrophic cardiomyopathy (HCM)-associated genetic variant (NM_000258.2:c.170C>A, NP_000249.1:p.Ala57Asp) in the sarcomeric gene MYL3, reported by the ClinVar database to be “likely pathogenic.” Human-induced pluripotent stem cells (iPSCs) were derived from the heterozygous VUSMYL3(170C>A) carrier, and their genome was edited using CRISPR/Cas9 to generate 4 isogenic iPSC lines(1) corrected “healthy” control; (2) homozygous VUSMYL3(170C>A); (3) heterozygous frameshift mutation MYL3; and (4) known heterozygous MYL3 pathogenic mutation (NM_000258.2:c.170C>G), at the same nucleotide position as VUSMYL3(170C>A), lines. Extensive assays including measurements of gene expression, sarcomere structure, cell size, contractility, action potentials, and calcium handling were performed on the isogenic iPSC-derived cardiomyocytes (iPSC-CMs).
RESULTS:The heterozygous VUSMYL3(170C>A)-iPSC-CMs did not show an HCM phenotype at the gene expression, morphology, or functional levels. Furthermore, genome-edited homozygous VUSMYL3(170C>A)- and frameshift mutation MYL3-iPSC-CMs lines were also asymptomatic, supporting a benign assessment for this particular MYL3 variant. Further assessment of the pathogenic nature of a genome-edited isogenic line carrying a known pathogenic MYL3 mutation, MYL3(170C>G), and a carrier-specific iPSC-CMs line, carrying a MYBPC3(961G>A) HCM variant, demonstrated the ability of this combined platform to provide both pathogenic and benign assessments.
CONCLUSIONS:Our study illustrates the ability of clustered regularly interspaced short palindromic repeats/Cas9 genome-editing of carrier-specific iPSCs to elucidate both benign and pathogenic HCM functional phenotypes in a carrier-specific manner in a dish. As such, this platform represents a promising VUS risk-assessment tool that can be used for assessing HCM-associated VUS specifically, and VUS in general, and thus significantly contribute to the arsenal of precision medicine tools available in this emerging field.
Quit attempters often have episodes of smoking relapse before they eventually quit. Interactive text messaging through mobile phones has been shown to increase abstinence. This service can be ...potentially applied on the platform of a social networking service to help quitters maintain abstinence.
Our aim was to determine if the group discussion and reminders via the WhatsApp or Facebook social group were effective to prevent smoking relapse in quitters who had stopped smoking recently.
This was a single-blinded, parallel, 3-arm pilot cluster randomized controlled trial allocating recent quitters, who had completed an 8-week treatment and reported abstinence for at least 7 days, to WhatsApp (n=42), Facebook (n=40), and a control group (n=54). The 2 intervention groups participated in a 2-month online group discussion with either WhatsApp or Facebook moderated by a trained smoking cessation counselor and received a self-help booklet on smoking cessation. The control group only received the booklet. The primary outcome was the 2- and 6-month relapse rates, defined as the proportion of participants who smoked at least 5 cigarettes in 3 consecutive days.
Fewer participants in the WhatsApp group (17%, 7/42) reported relapse than the control group (42.6%, 23/54) at 2-month (OR 0.27, 95% CI 0.10-0.71) and 6-month (40.5%, 17/42 vs 61.1%, 33/54; OR 0.43, 95% CI 0.19-0.99) follow-ups. The Facebook group (30.0%, 12/40) had an insignificantly lower relapse rate than the control group (42.6%, 23/54) at 2-month (OR 0.58, 95% CI 0.24-1.37) and 6-month (52.5%, 13/40 vs 61.1%, 33/54; OR 0.70, 95% CI 0.31-1.61) follow-ups. The WhatsApp social groups had more moderators' posts (median 60, IQR 25 vs median 32, IQR 7; P=.05) and participants' posts (median 35, IQR 50 vs median 6, IQR 9; P=.07) than their Facebook counterparts, but the difference was insignificant.
The intervention via the WhatsApp social group was effective in reducing relapse probably because of enhanced discussion and social support. Inactive discussion in the Facebook social group might have attributed to the lower effectiveness.
Clinicaltrials.gov NCT02007369; https://clinicaltrials.gov/show/NCT02007369 (Archived by WebCite® at http://www.webcitation.org/6c3RbltQG).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Lamin A/C (LMNA) is one of the most frequently mutated genes associated with dilated cardiomyopathy (DCM). DCM related to mutations in LMNA is a common inherited cardiomyopathy that is associated ...with systolic dysfunction and cardiac arrhythmias. Here we modelled the LMNA-related DCM in vitro using patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). Electrophysiological studies showed that the mutant iPSC-CMs displayed aberrant calcium homeostasis that led to arrhythmias at the single-cell level. Mechanistically, we show that the platelet-derived growth factor (PDGF) signalling pathway is activated in mutant iPSC-CMs compared to isogenic control iPSC-CMs. Conversely, pharmacological and molecular inhibition of the PDGF signalling pathway ameliorated the arrhythmic phenotypes of mutant iPSC-CMs in vitro. Taken together, our findings suggest that the activation of the PDGF pathway contributes to the pathogenesis of LMNA-related DCM and point to PDGF receptor-β (PDGFRB) as a potential therapeutic target.
Objectives
To develop a local consensus to guide medical practitioners and psychiatrists on the use of bupropion in different psychiatric conditions in Hong Kong.
Methods
By utilizing the modified ...Delphi technique, a group of 10 local physicians with extensive experience in the management of major depressive disorder (MDD) developed and voted (using an anonymous, electronic voting system) on the practicality of recommendation of a set of consensus statements on the clinical use and understanding of bupropion in Hong Kong.
Results
There was a very high degree of agreement among the panelists on the 11 finalized consensus statements.
Conclusions
The present consensus statements are developed as general recommendations for medical practitioners and psychiatrists to be practically referred to in clinical settings.
This study characterized cancer stem cells (CSCs) in hepatocellular carcinoma (HCC) cell lines, tumor specimens, and blood samples. The CD90
+ cells, but not the CD90
− cells, from HCC cell lines ...displayed tumorigenic capacity. All the tumor specimens and 91.6% of blood samples from liver cancer patients bore the CD45
−CD90
+ population, which could generate tumor nodules in immunodeficient mice. The CD90
+CD44
+ cells demonstrated a more aggressive phenotype than the CD90
+CD44
− counterpart and formed metastatic lesions in the lung of immunodeficient mice. CD44 blockade prevented the formation of local and metastatic tumor nodules by the CD90
+ cells. Differential gene expression profiles were identified in the CD45
−CD90
+ and CD45
−CD90
− cells isolated from tissue and blood samples from liver cancer patients and controls.
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