Spatial Multiplexing of Fluorescent Reporters for Imaging Signaling Network Dynamics.

In order to analyze how a signal transduction network converts cellular inputs into cellular outputs, ideally one would measure the dynamics of many signals within the network simultaneously. We found that, by fusing a fluorescent reporter to a pair of self-assembling peptides, it could be stably clustered within cells at random points, distant enough to be resolved by a microscope but close enough to spatially sample the relevant biology. Because such clusters, which we call signaling reporter islands (SiRIs), can be modularly designed, they permit a set of fluorescent reporters to be efficiently adapted for simultaneous measurement of multiple nodes of a signal transduction network within single cells. We created SiRIs for indicators of second messengers and kinases and used them, in hippocampal neurons in culture and intact brain slices, to discover relationships between the speed of calcium signaling, and the amplitude of PKA signaling, upon receiving a cAMP-driving stimulus.

Photo-expansion microscopy enables super-resolution imaging of cells embedded in 3D hydrogels.

Hydrogels are extensively used as tunable, biomimetic three-dimensional cell culture matrices, but optically deep, high-resolution images are often difficult to obtain, limiting nanoscale quantification of cell-matrix interactions and outside-in signalling. Here we present photopolymerized hydrogels for expansion microscopy that enable optical clearance and tunable ×4.6-6.7 homogeneous expansion of not only monolayer cell cultures and tissue sections, but cells embedded within hydrogels. The photopolymerized hydrogels for expansion microscopy formulation relies on a rapid photoinitiated thiol/acrylate mixed-mode polymerization that is not inhibited by oxygen and decouples monomer diffusion from polymerization, which is particularly beneficial when expanding cells embedded within hydrogels. Using this technology, we visualize human mesenchymal stem cells and their interactions with nascently deposited proteins at <120 nm resolution when cultured in proteolytically degradable synthetic polyethylene glycol hydrogels. Results support the notion that focal adhesion maturation requires cellular fibronectin deposition; nuclear deformation precedes cellular spreading; and human mesenchymal stem cells display cell-surface metalloproteinases for matrix remodelling.

Novel scoring system derived from meta-analysis and validated in cohort population for predicting 1-year atrial fibrillation recurrence after cryoballoon catheter ablation: The HeLPS-Cryo score.

BACKGROUND: Atrial fibrillation (AF) recurrence rates in 1 year after cryoballoon ablation catheter (CBCA) are still high. We purposed to identify strong predictors for AF recurrence after the successful CBCA procedure and develop a new scoring system based only on pre-procedural parameters. METHODS: In the derivation phase, a systematic review and meta-analysis identified the strong predictors of AF recurrence after the CBCA. The pooled hazard ratio (HR) was used to create the new scoring system. The second phase validated the new scoring system in the cohort population. RESULTS: A meta-analysis including 29 cohort studies with 16196 participants confirmed that persistent AF, stroke, heart failure, and left atrial diameter (LAD) >40 mm were powerful predictors for AF recurrence after the CBCA procedure. The HeLPS-Cryo (heart failure [1], left atrial dilatation [1], persistent AF [2], and stroke [2]) was developed based on those pre-procedural predictors. It was validated in 140 patients receiving CBCA procedures and revealed excellent predictive performance for 1-year AF recurrence (AUC = 0.8877; 95% CI = 0.8208 to 0.9546). The HeLPS-Cryo score of ≥3 could predict 1-year AF recurrence with sensitivity and specificity of 78.9% and 87.9%, respectively. The positive predictive value was 66.7%, and the negative predictive value was 93.1%. CONCLUSION: The HeLPS-Cryo score can help the physician estimate the probability of 1-year AF recurrence after the successful CBCA procedure. Patients with HeLPS-Cryo score <3 are good candidates for the CBCA procedure.

Recommended assessment and management of sleep disordered breathing in patients with atrial fibrillation, hypertension and heart failure: Taiwan Society of Cardiology/Taiwan Society of sleep Medicine/Taiwan Society of pulmonary and Critical Care Medicine joint consensus statement.

Sleep disordered breathing (SDB) is highly prevalent and may be linked to cardiovascular disease in a bidirectional manner. The Taiwan Society of Cardiology, Taiwan Society of Sleep Medicine and Taiwan Society of Pulmonary and Critical Care Medicine established a task force of experts to evaluate the evidence regarding the assessment and management of SDB in patients with atrial fibrillation (AF), hypertension and heart failure with reduced ejection fraction (HFrEF). The GRADE process was used to assess the evidence associated with 15 formulated questions. The task force developed recommendations and determined strength (Strong, Weak) and direction (For, Against) based on the quality of evidence, balance of benefits and harms, patient values and preferences, and resource use. The resulting 11 recommendations are intended to guide clinicians in determining which the specific patient-care strategy should be utilized by clinicians based on the needs of individual patients.

Minimal Fluoroscopic Catheter Ablation for Adult Patients with Paroxysmal Supraventricular Tachycardia without the Assistance of Intracardiac Echocardiography.

Background: Radiation exposure during fluoroscopic procedures increases the risk of cancer for both patients and operators. Objectives: The aim of this study was to investigate the safety and efficacy of adopting a three-dimensional electroanatomical mapping (3D EAM) system during ablation for paroxysmal supraventricular tachycardia (PSVT), without the assistance of intracardiac echocardiography (ICE), for both right- and left-chamber cardiac procedures. Methods: We retrospectively enrolled all patients with PSVT from September 2018 to December 2020. The patients were grouped according to the use of the 3D EAM system (3D-guided group, n = 102 vs. conventional group, n = 226). Results: The acute success rates were high in both groups (100% vs. 99.1%). The fluoroscopy time was significantly lower in the 3D-guided group than in the conventional group (2.4 ± 4.4 vs. 19.0 ± 10.8 min); the procedure time was significantly increased in the 3D-guided group (104.5 ± 29.9 vs. 94.0 ± 31.9 min), and this was associated with the post-electrophysiology test diagnosis after adjustment for multiple variables [standardized B coefficient (ß) 0.188]. There was no learning curve for each electrophysiologist in terms of fluoroscopy and procedure times. Conclusions: The 3D EAM system, without the assistance of ICE, was safe and effective in guiding PSVT ablation in both left- and right-chamber ablation.

Clinical manifestations and genetic characteristics in the Taiwan thoracic aortic aneurysm and dissection cohort - a prospective cohort study.

BACKGROUND: Thoracic aortic aneurysm and dissection (TAAD) is a devastating but treatable disease if detected early. The clinical manifestations and genetic characteristics underlying TAAD patients in Taiwan, however, remain unclear. METHODS: We consecutively recruited patients referred for TAAD screening and/or management at a tertiary medical center in Taiwan. All patients received a comprehensive survey of the clinical manifestations and a genetic testing with a 29-gene next-generation sequencing (NGS) panel. RESULTS: Patients (n = 107) were referred for different reasons, and could be grouped into 4 categories: known aortic aneurysm or dissection (AoAD) (n = 57), Marfanoid features (n = 36), having family members of suspected AoAD (n = 11), and ectopic lens (n = 3). AoAD were confirmed in 73 (68.2%) of the entire cohort. Among all the clinical manifestations, skin striae distensae was the only physical sign that showed significant association with AoAD (p = 0.007 after adjusted). Disease-causing genes/variants were identified in 46 patients (43.0%); FBN1 was the most prevalent disease-causing gene, followed by TGFBR1, TGFBR2 and FBN2. A positive genetic testing was not only an independent predictor of AoAD (hazard ratio (HR) 3.468, 95% confidence interval (CI) [1.541-7.807], p = 0.003), but also had a higher chance of dissection among the patients with known dilated aorta (HR 4.552, 95% CI [1.578-13.135], p = 0.005). CONCLUSION: The presence of skin striae distensae may serve as a clinical cue for physicians to search for AoAD in subjects who are at risk. The NGS panel test not only helps confirm the diagnosis, but also stratify the risk of dissection among patients with dilated aorta.

Higher long-term visit-to-visit glycemic variability predicts new-onset atrial fibrillation in patients with diabetes mellitus.

BACKGROUND: Atrial fibrillation (AF) is prevalent in patients with type 2 diabetes mellitus (T2DM). Glycemic variability (GV) is associated with risk of micro- and macrovascular diseases. However, whether the GV can increase the risk of AF remains unknown. METHODS: The cohort study used a database from National Taiwan University Hospital, a tertiary medical center in Taiwan. Between 2014 and 2019, a total of 27,246 adult patients with T2DM were enrolled for analysis. Each individual was assessed to determine the coefficients of variability of fasting glucose (FGCV) and HbA1c variability score (HVS). The GV parameters were categorized into quartiles. Multivariate Cox regression models were employed to estimate the relationship between the GV parameters and the risk of AF, transient ischemic accident (TIA)/ischemic stroke and mortality in patients with T2DM. RESULTS: The incidence rates of AF and TIA/ischemic stroke were 21.31 and 13.71 per 1000 person-year respectively. The medium follow-up period was 70.7 months. In Cox regression model with full adjustment, the highest quartile of FGCV was not associated with increased risk of AF [Hazard ratio (HR): 1.12, 95% confidence interval (CI) 0.96-1.29, p = 0.148] or TIA/ischemic stroke (HR: 1.04, 95% CI 0.83-1.31, p = 0.736), but was associated with increased risk of total mortality (HR: 1.33, 95% CI 1.12-1.58, p < 0.001) and non-cardiac mortality (HR: 1.41, 95% CI 1.15-1.71, p < 0.001). The highest HVS was significantly associated with increased risk of AF (HR: 1.29, 95% CI 1.12-1.50, p < 0.001), total mortality (HR: 2.43, 95% CI 2.03-2.90, p < 0.001), cardiac mortality (HR: 1.50, 95% CI 1.06-2.14, p = 0.024) and non-cardiac mortality (HR: 2.80, 95% CI 2.28-3.44, p < 0.001) but was not associated with TIA/ischemic stroke (HR: 0.98, 95% CI 0.78-1.23, p = 0.846). The Kaplan-Meier analysis showed significantly higher risk of AF, cardiac and non-cardiac mortality according to the magnitude of GV (log-rank test, p < 0.001). CONCLUSIONS: Our data demonstrate that high GV is independently associated with the development of new-onset AF in patients with T2DM. The benefit of maintaining stable glycemic levels to improve clinical outcomes warrants further studies.

Cryoablation with an 8-mm tip catheter in the treatment of atrioventricular nodal re-entrant tachycardia: results from a randomized controlled trial (CRYOABLATE).

AIMS: This was a randomized controlled study performed to compare 8 mm-tip catheter cryoablation (CRYO) with radiofrequency ablation (RFA) in treating atrioventricular nodal re-entrant tachycardia (AVNRT). METHODS AND RESULTS: A total of 158 patients (103 women, mean age 48.9 ± 14.1) with symptomatic AVNRT (140 typical; 18 atypical) were randomized to undergo CRYO with an 8 mm-tip catheter (n = 80) or RFA (n = 78). The primary endpoint was a composite of acute procedural failure, inadvertent permanent atrioventricular block (AVB) and recurrence at 12 months. No significant difference was observed between CRYO and RFA groups in primary endpoint (7.5 vs. 11.5%; P = 0.764), 12-month recurrence rate (3.8 vs. 1.3%; P = 0.358), inadvertent permanent AVB (0 vs. 1.3%; P = 0.307), and acute procedural failure (3.7 vs. 9%; P = 0.128). In patients with acute procedure failure, success was achieved in 5 of 7 patients (71.4%) in RFA group and 2 of 3 patients (66.7%) in CRYO group on cross-over. There was no significant difference in procedural duration between CRYO and RFA groups (72.4 ± 41.6 vs. 63.7 ± 29.8 min; P = 0.13), but fluoroscopic duration in CRYO group was significantly shorter (3.4 ± 6.3 vs. 6.7 ± 7.4 min; P = 0.005). Patient pain score (2.7 ± 2.7 vs. 4.6 ± 2.7; P < 0.001) and operator stress score (2.3 ± 1.3 vs. 4.9 ± 2; P < 0.001) were significantly lower in CRYO group. CONCLUSIONS: Cryoablation with an 8 mm-tip catheter is shown to be comparable to RFA in treating AVNRT in terms of efficacy and safety. Additional advantages in CRYO include shorter fluoroscopic time, lower patient pain perception, and operator stress level.

Unique parallel radiations of high-mountainous species of the genus Sedum (Crassulaceae) on the continental island of Taiwan.

We explored the temporal and spatial diversification of the plant genus Sedum L. (Crassulaceae) in Taiwan based on molecular analysis of nrITS and cpDNA sequences from East Asian Sedum members. Our phylogenetic and ancestral area reconstruction analysis showed that Taiwanese Sedum comprised two lineages that independently migrated from Japan and Eastern China. Furthermore, the genetic distances among species in these two clades were smaller than those of other East Asian Sedum clades, and the Taiwanese members of each clade occupy extremely varied habitats with similar niches in high-mountain regions. These data indicate that species diversification occurred in parallel in the two Taiwanese Sedum lineages, and that these parallel radiations could have occurred within the small continental island of Taiwan. Moreover, the estimated time of divergence for Taiwanese Sedum indicates that the two radiations might have been correlated to the formation of mountains in Taiwan during the early Pleistocene. We suggest that these parallel radiations may be attributable to the geographical dynamics of Taiwan and specific biological features of Sedum that allow them to adapt to new ecological niches.

Pathogenic exon-trapping by SVA retrotransposon and rescue in Fukuyama muscular dystrophy.

Fukuyama muscular dystrophy (FCMD; MIM253800), one of the most common autosomal recessive disorders in Japan, was the first human disease found to result from ancestral insertion of a SINE-VNTR-Alu (SVA) retrotransposon into a causative gene. In FCMD, the SVA insertion occurs in the 3' untranslated region (UTR) of the fukutin gene. The pathogenic mechanism for FCMD is unknown, and no effective clinical treatments exist. Here we show that aberrant messenger RNA (mRNA) splicing, induced by SVA exon-trapping, underlies the molecular pathogenesis of FCMD. Quantitative mRNA analysis pinpointed a region that was missing from transcripts in patients with FCMD. This region spans part of the 3' end of the fukutin coding region, a proximal part of the 3' UTR and the SVA insertion. Correspondingly, fukutin mRNA transcripts in patients with FCMD and SVA knock-in model mice were shorter than the expected length. Sequence analysis revealed an abnormal splicing event, provoked by a strong acceptor site in SVA and a rare alternative donor site in fukutin exon 10. The resulting product truncates the fukutin carboxy (C) terminus and adds 129 amino acids encoded by the SVA. Introduction of antisense oligonucleotides (AONs) targeting the splice acceptor, the predicted exonic splicing enhancer and the intronic splicing enhancer prevented pathogenic exon-trapping by SVA in cells of patients with FCMD and model mice, rescuing normal fukutin mRNA expression and protein production. AON treatment also restored fukutin functions, including O-glycosylation of α-dystroglycan (α-DG) and laminin binding by α-DG. Moreover, we observe exon-trapping in other SVA insertions associated with disease (hypercholesterolemia, neutral lipid storage disease) and human-specific SVA insertion in a novel gene. Thus, although splicing into SVA is known, we have discovered in human disease a role for SVA-mediated exon-trapping and demonstrated the promise of splicing modulation therapy as the first radical clinical treatment for FCMD and other SVA-mediated diseases.

Impaired viability of muscle precursor cells in muscular dystrophy with glycosylation defects and amelioration of its severe phenotype by limited gene expression.

A group of muscular dystrophies, dystroglycanopathy is caused by abnormalities in post-translational modifications of dystroglycan (DG). To understand better the pathophysiological roles of DG modification and to establish effective clinical treatment for dystroglycanopathy, we here generated two distinct conditional knock-out (cKO) mice for fukutin, the first dystroglycanopathy gene identified for Fukuyama congenital muscular dystrophy. The first dystroglycanopathy model-myofiber-selective fukutin-cKO [muscle creatine kinase (MCK)-fukutin-cKO] mice-showed mild muscular dystrophy. Forced exercise experiments in presymptomatic MCK-fukutin-cKO mice revealed that myofiber membrane fragility triggered disease manifestation. The second dystroglycanopathy model-muscle precursor cell (MPC)-selective cKO (Myf5-fukutin-cKO) mice-exhibited more severe phenotypes of muscular dystrophy. Using an isolated MPC culture system, we demonstrated, for the first time, that defects in the fukutin-dependent modification of DG lead to impairment of MPC proliferation, differentiation and muscle regeneration. These results suggest that impaired MPC viability contributes to the pathology of dystroglycanopathy. Since our data suggested that frequent cycles of myofiber degeneration/regeneration accelerate substantial and/or functional loss of MPC, we expected that protection from disease-triggering myofiber degeneration provides therapeutic effects even in mouse models with MPC defects; therefore, we restored fukutin expression in myofibers. Adeno-associated virus (AAV)-mediated rescue of fukutin expression that was limited in myofibers successfully ameliorated the severe pathology even after disease progression. In addition, compared with other gene therapy studies, considerably low AAV titers were associated with therapeutic effects. Together, our findings indicated that fukutin-deficient dystroglycanopathy is a regeneration-defective disorder, and gene therapy is a feasible treatment for the wide range of dystroglycanopathy even after disease progression.

Acute effects of biventricular pacing in heart failure patients with a normal ejection fraction and mechanical dyssynchrony.

OBJECTIVES: We tested the acute effects of resynchronization in heart failure patients with a normal (>50%) left ventricular (LV) ejection fraction (HFNEF) and mechanical dyssynchrony. METHODS: Twenty-four HFNEF patients (72 ± 6 years, 5 male) with mechanical dyssynchrony (standard deviation of electromechanical time delay among 12 LV segments >35 ms) were studied with temporary pacing catheters in the right atrium, LV, and right ventricle (RV), and high-fidelity catheters for pressure recording. Using selected atrioventricular (AV) intervals of 60, 90, 120, 150, and 180 ms to optimize transmitral flow during simultaneous biventricular pacing, the RV-LV (VV) interval was then evaluated at RV30, RV15, 0, LV15, LV30, and LV45 (RV or LV indicates which ventricle was paced first, the number indicates by how many ms). RESULTS: During simultaneous pacing, longer AV intervals were associated with improved LV pressure-derivative minimums and increased aortic pressures (p < 0.05 vs. normal sinus rhythm). In the VV interval from RV30 to LV45, there was a graded increase in the aortic velocity time integral and a decrease in dyssynchrony during simultaneous or LV-first pacing (p < 0.05 vs. normal sinus rhythm). CONCLUSIONS: For HFNEF patients with mechanical dyssynchrony, acute simultaneous biventricular or LV-first pacing with longer AV intervals reduced mechanical dyssynchrony and improved diastolic and systolic hemodynamics.

Unique clinical characteristics and SCN5A mutations in patients with Brugada syndrome in Taiwan.

BACKGROUND/PURPOSE: Brugada syndrome (BrS) is a hereditable sudden cardiac death (SCD). Mutations in the SCN5A gene (the most common BrS-causing gene) are responsible for 20-25% of this disease in Caucasian populations. However, the prevalence of SCN5A mutations in patients with BrS in the Chinese Han population in Taiwan remains unknown. Therefore, in this study, we investigated the prevalence of the SCN5A mutation in the largest BrS cohort in Taiwan. METHODS: We consecutively enrolled 47 unrelated patients with BrS from medical centers and hospitals in Taiwan between 2000 and 2010. Mutations within all the 27 translated exons, and exon-intron boundaries of the SCN5A-encoded cardiac sodium channel were screened in all patients with BrS using direct sequencing. A total of 500 unrelated healthy volunteers with a normal electrocardiogram were genotyped as a control group. RESULTS: SCN5A genetic variants were identified in 14 of the 47 patients with BrS and four of the 14 patients with BrS had missense mutations (1651 G>A, 1776 C>G, 3578 G>A). The prevalence rate of SCN5A mutations was approximately 8% (4/47), which was significantly lower than that reported in Caucasian populations (20-25%; p = 0.0007). The average age of these 14 BrS patients with SCN5A variants at diagnosis (12 men and 2 women) was 40 ± 13 years. Four patients experienced SCD, and six presented with seizure or syncope. Only three patients (3/14, 21.4%) had a family history of SCD. CONCLUSION: The prevalence of SCN5A mutations in the Chinese Han population in Taiwan may be lower than that reported in the Caucasian populations. In addition, most patients with BrS did not have a family history of SCD.

Association of Small-Conductance Calcium-Activated Potassium Channels and Atrial Fibrillation - How Far Have We Gone?

UNLABELLED: Atrial fibrillation (AF) is the most common sustained and most important arrhythmia in clinical practice. The mechanisms underlying AF initiation and maintenance are known to be complex and heterogeneous. The general understanding of the detailed molecular basis of AF is still incomplete. Recently, these is increasing evidence that small conductance calcium-activated potassium (SK) channels are associated with atrial action potential repolarization and the pathogenesis of AF. Although the functional role of SK channels in the genesis of AF is not entirely clear, new insights into the basic pathophysiological mechanism of AF have been provided. Besides, genome-wide association studies also implicate that genes coding for SK channels are related to the risk of developing AF. This article reviews recent work on the association of SK channels and AF, genetic studies of SK channels, and discuss future investigation and developments regarding this field. KEY WORDS: Atrial fibrillation; Genetics; Small conductance calcium-activated potassium channels.

Sex-based differences in obstructive sleep apnea and atrial fibrillation: Implication of atrial fibrillation burden.

Background: Obstructive sleep apnea (OSA) is a risk factor for atrial fibrillation (AF); however, it is unclear whether AF increases the risk of OSA. Furthermore, sex differences among patients with both AF and OSA remain unclear. We aimed to determine the association between an increased AF burden and OSA and investigate the differences in clinical characteristics between women and men with AF and OSA. Methods: This was a descriptive, cross-sectional analysis from a prospective cohort study. Patients with non-valvular AF were recruited from the cardiac electrophysiology clinic of a tertiary center; they underwent a home sleep apnea test and 14-day ambulatory electrocardiography. Moderate-to-severe OSA was defined as an apnea-hypopnea index of ≥15. Results: Of 320 patients with AF, 53.4% had moderate-to-severe OSA, and the mean body mass index (BMI) was 25.6 kg/m2. Less women (38.2%) had moderate-to-severe OSA than men (59.3%) (p < 0.001). In the multivariate analysis, age, being a man, and BMI were significantly associated with moderate-to-severe OSA. AF burden was associated with moderate-to-severe OSA only in men (odds ratio: 1.008; 95% confidence interval: 1.001-1.014). Women and men with OSA had similar BMI (p = 0.526) and OSA severity (p = 0.754), but women were older than men (70.1 ± 1.3 vs. 63.1 ± 0.9 years, p < 0.001). Women with moderate-to-severe OSA had a lower AF burden than men did (27.6 ± 7.1 vs. 49.5 ± 3.9%, p = 0.009). Conclusions: AF burden is a sex-specific risk factor for OSA and is limited to men. In contrast, women with both AF and OSA have a lower AF burden than men, despite being older and having similar OSA severity and body habitus. Thus, AF may develop later in women with OSA than in men.

Improved immunostaining of nanostructures and cells in human brain specimens through expansion-mediated protein decrowding.

Proteins are densely packed in cells and tissues, where they form complex nanostructures. Expansion microscopy (ExM) variants have been used to separate proteins from each other in preserved biospecimens, improving antibody access to epitopes. Here, we present an ExM variant, decrowding expansion pathology (dExPath), that can expand proteins away from each other in human brain pathology specimens, including formalin-fixed paraffin-embedded (FFPE) clinical specimens. Immunostaining of dExPath-expanded specimens reveals, with nanoscale precision, previously unobserved cellular structures, as well as more continuous patterns of staining. This enhanced molecular staining results in observation of previously invisible disease marker-positive cell populations in human glioma specimens, with potential implications for tumor aggressiveness. dExPath results in improved fluorescence signals even as it eliminates lipofuscin-associated autofluorescence. Thus, this form of expansion-mediated protein decrowding may, through improved epitope access for antibodies, render immunohistochemistry more powerful in clinical science and, perhaps, diagnosis.

Predicting impaired cardiopulmonary exercise capacity in patients with atrial fibrillation using a simple echocardiographic marker.

BACKGROUND: Exercise intolerance is a common symptom associated with atrial fibrillation (AF). However, echocardiographic markers that can predict impaired exercise capacity are lacking. OBJECTIVE: This study aimed to investigate the association between echocardiographic parameters and exercise capacity assessed by cardiopulmonary exercise testing in patients with AF. METHODS: This single-center prospective study enrolled patients with AF who underwent echocardiography and cardiopulmonary exercise testing to evaluate exercise capacity at a tertiary center for AF management from 2020 to 2022. Patients with valvular heart disease, reduced left ventricular ejection fraction, or documented cardiomyopathy were excluded. RESULTS: Of the 188 patients, 134 (71.2%) exhibited impaired exercise capacity (peak oxygen consumption ≤85%), including 4 (2.1%) having poor exercise capacity (peak oxygen consumption <50%). Echocardiographic findings revealed that these patients had an enlarged left atrial end-systolic diameter (LA); smaller left ventricular end-diastolic diameter (LVEDD); and increased relative wall thickness, tricuspid regurgitation velocity, and LA/LVEDD and E/e' ratios. In addition, they exhibited lower peak systolic velocity of the mitral annulus and LA reservoir strain. In the multivariate regression model, LA/LVEDD remained the only significant echocardiographic parameter after adjustment for age, sex, and body mass index (P = .020). This significance persisted even after incorporation of heart rate reserve, N-terminal pro-B-type natriuretic peptide level, and beta-blocker use into the model. CONCLUSION: In patients with AF, LA/LVEDD is strongly associated with exercise capacity. Further follow-up and validation are necessary to clarify its clinical implications in patient care.

Mislocalization of fukutin protein by disease-causing missense mutations can be rescued with treatments directed at folding amelioration.

Fukuyama-type congenital muscular dystrophy (FCMD), the second most common childhood muscular dystrophy in Japan, is caused by alterations in the fukutin gene. Mutations in fukutin cause abnormal glycosylation of α-dystroglycan, a cell surface laminin receptor; however, the exact function and pathophysiological role of fukutin are unclear. Although the most prevalent mutation in Japan is a founder retrotransposal insertion, point mutations leading to abnormal glycosylation of α-dystroglycan have been reported, both in Japan and elsewhere. To understand better the molecular pathogenesis of fukutin-deficient muscular dystrophies, we constructed 13 disease-causing missense fukutin mutations and examined their pathological impact on cellular localization and α-dystroglycan glycosylation. When expressed in C2C12 myoblast cells, wild-type fukutin localizes to the Golgi apparatus, whereas the missense mutants A170E, H172R, H186R, and Y371C instead accumulated in the endoplasmic reticulum. Protein O-mannose ß1,2-N-acetylglucosaminyltransferase 1 (POMGnT1) also mislocalizes when co-expressed with these missense mutants. The results of nocodazole and brefeldin A experiments suggested that these mutant proteins were not transported to the Golgi via the anterograde pathway. Furthermore, we found that low temperature culture or curcumin treatment corrected the subcellular location of these missense mutants. Expression studies using fukutin-null mouse embryonic stem cells showed that the activity responsible for generating the laminin-binding glycan of α-dystroglycan was retained in these mutants. Together, our results suggest that some disease-causing missense mutations cause abnormal folding and localization of fukutin protein, and therefore we propose that folding amelioration directed at correcting the cellular localization may provide a therapeutic benefit to glycosylation-deficient muscular dystrophies.

Soluble ST2 as a biomarker for detecting stable heart failure with a normal ejection fraction in hypertensive patients.

BACKGROUND: We investigated the measurement of soluble ST2 (sST2) in stable heart failure (HF) with a normal ejection fraction (HFNEF) in hypertensive patients. METHODS AND RESULTS: Echocardiography and serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) and sST2 concentrations were evaluated in 107 hypertensive patients (65 ± 12 years, 57 male) with ejection fraction (EF) >50%. Among them, 68 patients with stable HF in functional class II and III were the HFNEF group. We found that the area under the receiver operating characteristic curve (AUC) for sST2 was 0.80 (95% CI 0.70-0.89; P < .001), relatively better than that for NT-proBNP (AUC 0.70, 95% CI 0.58-0.79; P = .003) to detect HFNEF. However, the NT-proBNP concentration, rather than sST2, was higher in HFNEF patients with functional class III (562 ± 891 vs 185 ± 242 pg/mL in functional class II; P = .009), and correlated better with mitral E/e' (annular early diastolic velocity) (r = 0.327; P = .008) than sST2 concentrations in HFNEF patients. Multivariate analysis showed that sST2 >13.5 ng/mL was independently associated with HFNEF in hypertensive patients (odds ratio 11.7, 95% CI = 2.9-47.4; P = .001). CONCLUSIONS: sST2 measurement provides diagnostic aid of stable HFNEF for hypertensive patients. Addition of NT-proBNP to sST2 could give further information regarding HF functional class and diastolic abnormality.