Golgi apparatus-localized CATION CALCIUM EXCHANGER4 promotes osmotolerance of Arabidopsis

Calcium (Ca2+) is a major ion in living organisms, where it acts as a second messenger for various biological phenomena. The Golgi apparatus retains a higher Ca2+ concentration than the cytosol and returns cytosolic Ca2+ to basal levels after transient elevation in response to environmental stimuli such as osmotic stress. However, the Ca2+ transporters localized in the Golgi apparatus of plants have not been clarified. We previously found that a wild-type (WT) salt-tolerant Arabidopsis (Arabidopsis thaliana) accession, Bu-5, showed osmotic tolerance after salt acclimatization, whereas the Col-0 WT did not. Here, we isolated a Bu-5 background mutant gene, acquired osmotolerance-defective 6 (aod6), which reduces tolerance to osmotic, salt, and oxidative stresses, with a smaller plant size than the WT. The causal gene of the aod6 mutant encodes CATION CALCIUM EXCHANGER4 (CCX4). The aod6 mutant was more sensitive than the WT to both deficient and excessive Ca2+. In addition, aod6 accumulated higher Ca2+ than the WT in the shoots, suggesting that Ca2+ homeostasis is disturbed in aod6. CCX4 expression suppressed the Ca2+ hypersensitivity of the csg2 (calcium sensitive growth 2) yeast (Saccharomyces cerevisiae) mutant under excess CaCl2 conditions. We also found that aod6 enhanced MAP kinase 3/6 (MPK3/6)-mediated immune responses under osmotic stress. Subcellular localization analysis of mGFP-CCX4 showed GFP signals adjacent to the trans-Golgi apparatus network and co-localization with Golgi apparatus-localized markers, suggesting that CCX4 localizes in the Golgi apparatus. These results suggest that CCX4 is a Golgi apparatus-localized transporter involved in the Ca2+ response and plays important roles in osmotic tolerance, shoot Ca2+ content, and normal growth of Arabidopsis.

Mutations in nuclear pore complex promote osmotolerance in Arabidopsis by suppressing the nuclear translocation of ACQOS and its osmotically induced immunity

We have previously reported a wide variation in salt tolerance among Arabidopsis thaliana accessions and identified ACQOS, encoding a nucleotide-binding leucine-rich repeat (NLR) protein, as the causal gene responsible for the disturbance of acquired osmotolerance induced after mild salt stress. ACQOS is conserved among Arabidopsis osmosensitive accessions, including Col-0. In response to osmotic stress, it induces detrimental autoimmunity, resulting in suppression of osmotolerance, but how ACQOS triggers autoimmunity remains unclear. Here, we screened acquired osmotolerance (aot) mutants from EMS-mutagenized Col-0 seeds and isolated the aot19 mutant. In comparison with the wild type (WT), this mutant had acquired osmotolerance and decreased expression levels of pathogenesis-related genes. It had a mutation in a splicing acceptor site in NUCLEOPORIN 85 (NUP85), which encodes a component of the nuclear pore complex. A mutant with a T-DNA insertion in NUP85 acquired osmotolerance similar to aot19. The WT gene complemented the osmotolerant phenotype of aot19. We evaluated the acquired osmotolerance of five nup mutants of outer-ring NUPs and found that nup96, nup107, and aot19/nup85, but not nup43 or nup133, showed acquired osmotolerance. We examined the subcellular localization of the GFP-ACQOS protein and found that its nuclear translocation in response to osmotic stress was suppressed in aot19. We suggest that NUP85 is essential for the nuclear translocation of ACQOS, and the loss-of-function mutation of NUP85 results in acquired osmotolerance by suppressing ACQOS-induced autoimmunity in response to osmotic stress.

Plant size, latitude, and phylogeny explain within-population variability in herbivory

Interactions between plants and herbivores are central in most ecosystems, but their strength is highly variable. The amount of variability within a system is thought to influence most aspects of plant-herbivore biology, from ecological stability to plant defense evolution. Our understanding of what influences variability, however, is limited by sparse data. We collected standardized surveys of herbivory for 503 plant species at 790 sites across 116° of latitude. With these data, we show that within-population variability in herbivory increases with latitude, decreases with plant size, and is phylogenetically structured. Differences in the magnitude of variability are thus central to how plant-herbivore biology varies across macroscale gradients. We argue that increased focus on interaction variability will advance understanding of patterns of life on Earth.

MOS4-associated complex contributes to proper splicing and suppression of ER stress under long-term heat stress in Arabidopsis

Plants are often exposed not only to short-term (S-) but also to long-term (L-)heat stress over several consecutive days. A few Arabidopsis mutants defective in L-heat tolerance have been identified, but the molecular mechanisms are less understood for this tolerance than for S-heat stress tolerance. To elucidate the mechanisms of the former, we used a forward genetic screen for sensitive to long-term heat (sloh) mutants and isolated sloh3 and sloh63. The mutants were hypersensitive to L- but not to S-heat stress, and sloh63 was also hypersensitive to salt stress. We identified the causal genes, SLOH3 and SLOH63, both of which encoded splicing-related components of the MOS4-associated complex (MAC). This complex is widely conserved in eukaryotes and has been suggested to interact with spliceosomes. Both genes were induced by L-heat stress in a time-dependent manner, and some abnormal splicing events were observed in both mutants under L-heat stress. In addition, endoplasmic reticulum (ER) stress and subsequent unfolded protein response occurred in both mutants under L-heat stress and were especially prominent in sloh63, suggesting that enhanced ER stress is due to the salt hypersensitivity of sloh63. Splicing inhibitor pladienolide B led to concentration-dependent disturbance of splicing, decreased L-heat tolerance, and enhanced ER stress. These findings suggest that maintenance of precise mRNA splicing under L-heat stress by the MAC is important for L-heat tolerance and suppressing ER stress in Arabidopsis.

LHT1/MAC7 contributes to proper alternative splicing under long-term heat stress and mediates variation in the heat tolerance of Arabidopsis

Natural genetic variation has facilitated the identification of genes underlying complex traits such as stress tolerances. We here evaluated the long-term (L-) heat tolerance (37°C for 5 days) of 174 Arabidopsis thaliana accessions and short-term (S-) heat tolerance (42°C, 50 min) of 88 accessions and found extensive variation, respectively. Interestingly, L-heat-tolerant accessions are not necessarily S-heat tolerant, suggesting that the tolerance mechanisms are different. To elucidate the mechanisms underlying the variation, we performed a chromosomal mapping using the F2 progeny of a cross between Ms-0 (a hypersensitive accession) and Col-0 (a tolerant accession) and found a single locus responsible for the difference in L-heat tolerance between them, which we named Long-term Heat Tolerance 1 (LHT1). LHT1 is identical to MAC7, which encodes a putative RNA helicase involved in mRNA splicing as a component of the MOS4 complex. We found one amino acid deletion in LHT1 of Ms-0 that causes a loss of function. Arabidopsis mutants of other core components of the MOS4 complex-mos4-2, cdc5-1, mac3a mac3b, and prl1 prl2-also showed hypersensitivity to L-heat stress, suggesting that the MOS4 complex plays an important role in L-heat stress responses. L-heat stress induced mRNA processing-related genes and compromised alternative splicing. Loss of LHT1 function caused genome-wide detrimental splicing events, which are thought to produce nonfunctional mRNAs that include retained introns under L-heat stress. These findings suggest that maintaining proper alternative splicing under L-heat stress is important in the heat tolerance of A. thaliana.

Efficient gene transduction in pigs and macaques with the engineered AAV vector AAV.GT5 for hemophilia B gene therapy

Gene therapy using adeno-associated virus (AAV)-based vectors has become a realistic therapeutic option for hemophilia. We examined the potential of a novel engineered liver-tropic AAV3B-based vector, AAV.GT5, for hemophilia B gene therapy. In vitro transduction with AAV.GT5 in human hepatocytes was more than 100 times higher than with AAV-Spark100, another bioengineered vector used in a clinical trial. However, liver transduction following intravenous injection of these vectors was similar in mice with a humanized liver and in macaques. This discrepancy was due to the low recovery and short half-life of AAV.GT5 in blood, depending on the positive charge of the heparin-binding site in the capsid. Bypassing systemic clearance with the intra-hepatic vascular administration of AAV.GT5, but not AAV-Spark100, enhanced liver transduction in pigs and macaques. AAV.GT5 did not develop neutralizing antibodies (NAbs) in two of four animals, while AAV-Spark100 induced serotype-specific NAbs in all macaques tested (4 of 4). The NAbs produced after AAV-Spark100 administration were relatively serotype specific, and challenge with AAV.GT5 through the hepatic artery successfully boosted liver transduction in one animal previously administered AAV-Spark100. In summary, AAV.GT5 showed different vector kinetics and NAb induction compared with AAV-Spark100, and intra-hepatic vascular administration may minimize the vector dose required and vector dissemination.

Abscisic acid-mediated sugar responses are essential for vegetative desiccation tolerance in the liverwort Marchantia polymorpha

Low-molecular-weight sugars serve as protectants for cellular membranes and macromolecules under the condition of dehydration caused by environmental stress such as desiccation and freezing. These sugars also affect plant growth and development by provoking internal signaling pathways. We previously showed that both sugars and the stress hormone abscisic acid (ABA) enhance desiccation tolerance of gemma, a dormant propagule of the liverwort Marchantia polymorpha. To determine the role of ABA in sugar responses in liverworts, we generated genome-editing lines of M. polymorpha ABA DEFICIENT 1 (MpABA1) encoding zeaxanthin epoxidase, which catalyzes the initial reaction toward ABA biosynthesis. The generated Mpaba1 lines that accumulated only a trace amount of endogenous ABA showed reduced desiccation tolerance and reduced sugar responses. RNA-seq analysis of sucrose-treated gemmalings of M. polymorpha revealed that expression of a large part of sucrose-induced genes was reduced in Mpaba1 compared to the wild-type. Furthermore, Mpaba1 accumulated smaller amounts of low-molecular-weight sugars in tissues upon sucrose treatment than the wild-type, with reduced expression of genes for sucrose synthesis, sugar transporters, and starch-catabolizing enzymes. These results indicate that endogenous ABA plays a role in the regulation of the positive feedback loop for sugar-induced sugar accumulation in liverworts, enabling the tissue to have desiccation tolerance.

Relation of lymphopenia to comorbidity burden and its prognostic value in patients with acute decompensated heart failure with preserved left ventricular ejection fraction: a multicentre study

Background

Systemic inflammation resulting from comorbidities is postulated to play a central role in the pathophysiology of heart failure (HF) with preserved ejection fraction (HFpEF). Lymphopenia is a common manifestation of systemic inflammation and a prognostic factor in patients with HF. However, the association of lymphopenia with the comorbidity burden is unknown, and its prognostic value in patients with HFpEF admitted due to acute decompensated heart failure (ADHF) also remains elusive.

Purpose

We sought to clarify the relation of lymphopenia with the comorbidity burden, as well as its prognostic value and complementarity with the Get with the Guidelines-Heart Failure (GWTG-HF) risk score in ADHF patients with HFpEF.

Methods

Patients' data were extracted from the Prospective mUlticenteR obServational stUdy of patIenTs with Heart Failure with Preserved Ejection Fraction (PURSUIT-HFpEF), which is a prospective multicentre registry for patients with ADHF with a LVEF ≥50%. We analysed data of patients admitted between June 2016 and December 2020 who survived to discharge. The total lymphocyte count (per μL) and GWTG-HF risk score were obtained on admission, as previously reported. Comorbidity burden was defined as the number of comorbidities from the following: atrial fibrillation, hypertension, diabetes mellitus, coronary artery disease, chronic kidney disease, chronic obstructive pulmonary disease, anaemia, and obesity. The study endpoint was all-cause death.

Results

Over a median follow-up of 417 days, 181 of the 1013 included patients died. The proportion of patients with a total lymphocyte count in the lowest tertile was increasing with the increase in comorbidity burden (Figure 1). In the multivariate Cox analysis, a total lymphocyte count in the intermediate (hazard ratio [HR] 1.55, 95% confidence interval [CI] 1.00–2.41, p=0.0486) and lowest tertile (HR 2.23, 95% CI 1.47–3.38, p=0.0002) was independently associated with all-cause death. There was a significant difference in the all-cause death rate among the groups stratified by total lymphocyte count tertile (Figure 2). The total lymphocyte count had a higher C-statistic value (0.627) for the prediction of all-cause death than the GWTG-HF risk score, and the C-statistic value of the GWTG-HF risk score was improved when the total lymphocyte count was added (0.613 to 0.636, p=0.0260).

Conclusions

Lymphopenia was significantly associated with comorbidity burden. Furthermore, it was a useful marker of poor prognosis in hospitalised patients with acute HFpEF and was shown to be complementary to the contemporary HF prognostic score.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Roche Diagnostics K.K.Fuji Film Toyama Chemical Co. Ltd.

Clinical trajectory and outcomes of patients with heart failure with preserved ejection fraction with normal or indeterminate diastolic function

Background

Heart failure (HF) with preserved ejection fraction (HFpEF) is a chronic and progressive disease, but limited therapeutic strategies are currently available. Although left ventricular diastolic dysfunction (DD) is a prominent mechanism of HFpEF, a certain number of patients with HFpEF have a normal diastolic function (ND) or indeterminate diastolic function (ID). With the progressive nature of HFpEF, diastolic function may change over time. However, the change of diastolic function, its predictor and prognosis in patients with clinically established HFpEF remains unknown.

Purpose

To investigate the clinical trajectory and outcomes of patients with HFpEF with ND or ID and to identify factors associated with progression from ND or ID at discharge to DD at 1-year follow-up.

Methods

Using data from a prospective multicenter observational study of patients with HFpEF, we extracted 289 patients with HFpEF with ND or ID at discharge who had echocardiographic data at 1-year follow-up for the re-evaluation of diastolic function. Diastolic function was assessed according to the 2016 American Society of Echocardiography recommendations. Patients were classified according to the absence or presence of progression from ND or ID to DD at 1 year. The primary endpoint was a composite of all-cause death and HF rehospitalization.

Results

Median age was 81 years, and 138 (47.8%) patients were female. At 1 year, 107 (37%) patients progressed to DD. During a median follow-up of 709 days, the composite endpoint occurred in 90 (31.1%) patients. Compared to patients without progression to DD, those with progression to DD had a significantly higher cumulative incidence rate of the composite endpoint (incidence rate: 11.7/100 person-year versus 23.3/100 person-year, P<0.001). Progression to DD (adjusted HR: 2.014, 95% CI: 1.239–3.273, P=0.005) was independently associated with the composite endpoint. Age (adjusted OR: 1.046, 95% CI: 1.008–1.087, P=0.018), body mass index (BMI) (adjusted OR: 1.107, 95% CI: 1.029–1.192, P=0.006), and serum albumin (adjusted OR: 0.459, 95% CI: 0.216–0.974, P=0.042) were independently associated with progression from ND or ID to DD at 1 year.

Conclusion

More than one-third of patients with HFpEF with ND or ID progressed to DD at 1 year and had poor clinical outcomes. Age, BMI, and serum albumin were independently associated with this progression.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by grants from Japan Society for the Promotion of Science KAKENHI (No. JP 17K09496) and Japan Agency for Medical Research and Development (No. JP16lk1010013).

Extensive ablation strategy for persistent atrial fibrillation impairs left atrial function but reduces recurrence rate

Background

In catheter ablation for persistent atrial fibrillation (AF), extensive ablation strategy, such as linear ablation and/or complex fractionated atrial electrogram (CFAE) ablation in addition to pulmonary vein isolation (PVI-plus), might impair left atrial function more severely than PVI-alone strategy.

Purpose

The aim of this study is to investigate the impact of extensive ablation strategy on LA function and assess the relationship between post-ablation LA function and recurrence.

Methods

This study is a post-hoc subanalysis of the EARNEST-PVI randomized controlled trial, which investigated the efficacy of the PVI-alone strategy in comparison with PVI-plus strategy for persistent AF. From the 497 participants of EARNEST-PVI trial, we enrolled 191 patients with full datasets of pre- and post-ablation cardiac computed tomography (CT) at our Hospital. Patients were divided into PVI-alone and PVI-plus groups. Within one month before and 3 months after ablation, LA volume index (LAVI) and LA emptying fraction (LAEF) were calculated by using the Comprehensive Cardiac Analysis software on the Extended Brilliance Workspace. We assessed i) post-ablation LA function, ii) AF/atrial tachycardia (AT) -free rate after single and final session, and iii) relationship between post-ablation LAEF and ablation success in each group.

Results

The indices of baseline LA remodeling were not different between PVI-alone (N=96) and PVI-plus groups (N=95) [LAVI: 71.4 (57.8, 82.0) vs. 68.7 (61.0, 78.1), P=0.92, LAEF: 13.7 (10.0, 17.4) vs. 13.0 (10.0, 16.9), PVI-alone vs. PVI-plus, P=0.78]. In overall patients, post-ablation LAEF did not differ among them [34.4 (26.1, 40.7) vs. 31.6 (26.0, 37.4), P=0.13]. In the analysis of patients showing sinus rhythm during the CT study, LAEF was significantly higher in PVI-alone (N=87) than in PVI-plus group (N=93) [35.7 (29.0, 41.0) vs. 31.7 (26.1, 37.5), P=0.011] (Figure 1A). AF/AT-free survival rate during median follow-up of 44 months was not different after first session (63.5% vs. 68.4%, P=0.33), while PVI-plus had a tendency towards higher success rate after final session (72.9% vs. 84.2%, P=0.053) (Figure 2). In receiver operating characteristics analysis for recurrence after first session, post-ablation decreased LAEF had significantly related to recurrence after PVI-alone (AUC: 0.733, P<0.0001), but not after PVI-plus (AUC: 0.567, P=0.31) (Figure 1B, C).

Conclusion

Compared with PVI-alone strategy, PVI-plus strategy damaged LA function more severely, but tended to be related to higher success rate. Post-ablation LA function was related to recurrence in PVI-alone, but not in PVI-plus. Extensive ablation might have additional anti-arrhythmic effect regardless of iatrogenic myocardial damage. Myocardial injury by extensive ablation may less attribute to recurrence than intrinsic damage of LA.

Funding Acknowledgement

Type of funding sources: None.

Development of the new risk score to predict occurrence of atrial fibrillation early after acute myocardial infarction

Background/Introduction

New onset of atrial fibrillation (AF) is associated with adverse short- and long-term outcomes after acute myocardial infarction (AMI), and its prediction is relevant for the risk stratification in patients with AMI. Although several risk scores were developed for AF in the general population, there is no established risk score for AF occurrence after AMI.

Purpose

To develop a risk score to predict occurrence of AF early after AMI.

Methods

We enrolled consecutive 751 patients with AMI who admitted to our hospital between April 2006 and September 2012 for the present study. New occurrence of AF was defined as AF detected during hospital stay in a patient showing normal regular sinus rhythm at admission. Parameters relevant to the occurrence of AF was selected from the clinical characteristics, physical status and blood test data at admission, and peak CK/CK-MB, by stepwise logistic regression analysis. We constructed a risk score model to predict the new occurrence of AF, using selected parameters and their logistic regression coefficients. C-statistics was determined by constructing a receiver operating characteristic curve to evaluate the accuracy of the risk score for prediction of AF occurrence.

Results

We excluded 48 patients (6.4%) who had AF at admission, and 208 patients without sufficient data at admission, and thus, the study group consisted of 459 patients (age; 65±13 years, male gender; 79.6%). New AF occurrence was observed in 72 patients (14.5%). The following 7 parameters was selected as parameters related with AF (as p<0.1); Inferior/posterior AMI, use of β blockers, use of diuretics, single vessel disease, absence of reperfusion therapy, systolic blood pressure (sBP) at admission, and smoking. One point was given to sBP>128mmHg, 2 points to absence of reperfusion, and one point to other parameters. Sum of these points was calculated as the AF risk score (Table 1). AF occurred in 27.1% of patients with ≥5 points whereas it was observed 5.2% of those with <5 points. C-statistics of the risk score was 0.75 (95% CI 0.68–0.83).

Conclusion

We developed a novel risk score to estimate the risk of AF occurrence early after AMI, which can be a useful tool for the risk stratification after AMI.

Funding Acknowledgement

Type of funding sources: None.

Association between prognosis and the use of angiotensin-converting enzyme inhibitors and/or angiotensin II receptor blocker in frail patients with heart failure with preserved ejection fraction

Background

The effectiveness of angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin II receptor blockers (ARB) has not been demonstrated in patients with heart failure with preserved ejection fraction (HFpEF). We recently reported significant interaction between the use of ACE-I and/or ARB (ACE-I/ARB) and frailty on prognosis in patients with HFpEF.

Purpose

In the present study, we examined the association between ACE-I/ARB and prognosis in patients with HFpEF stratified by the presence or absence of frailty.

Methods

We examined the association between the use of ACE-I/ARB and prognosis according to the presence (Clinical Frailty Scale (CFS) ≥5) or absence (CFS ≤4) of frailty in patients with HFpEF in a post-hoc analysis of registry data. Primary endpoint was the composite of all-cause mortality and heart failure admission. Secondary endpoints were all-cause mortality and heart failure admission.

Results

Of 1059 patients, median age was 83 years and 45% were male. Kaplan-Meier analysis showed that the risk of composite endpoint (log-rank P=0.001) and all-cause death (log-rank P=0.005) in patients with ACE-I/ARB was lower in those with CFS ≥5, but similar between patients with and without ACE-I/ARB in patients with CFS ≤4 (composite endpoint: log-rank P=0.830; all-cause death: log-rank P=0.192). In a multivariable Cox proportional hazards model, use of ACE-I/ARB was significantly associated with lower risk of the composite endpoint (hazard ratio = 0.52, 95% CI: 0.33–0.83, P=0.005) and heart failure admission (hazard ratio = 0.45, 95% CI: 0.25–0.83, P=0.010) in patients with CFS ≥5, but not in patients with CFS ≤4 (composite endpoint: hazard ratio = 1.41, 95% CI: 0.99–2.02, P=0.059; heart failure admission: hazard ratio = 1.43, 95% CI: 0.94–2.18, P=0.091). The association between ACE-I or ARB and prognosis did not significantly differ by CFS (CFS ≤4: log-rank P=0.562; CFS ≥5: log-rank P=0.100, for with ACE-I vs. ARB, respectively). Adjusted HRs for CFS 1–4 were higher than 1.0, but were less than 1.0 at CFS 5.

Conclusions

In patients with HFpEF, use of ACE-I/ARB was associated with better prognosis in patients with frailty as assessed with the CFS, but not in those without frailty.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Roche

The clinical relevance of quality of life in patients with acute decompensated heart failure with preserved ejection fraction: insights from the PURSUIT-HFpEF Registry

Background

Improvement of quality of life (QOL) is one of the most important therapeutic goals for patients with heart failure with preserved ejection fraction (HFpEF). It is, therefore, clinically relevant to comprehensively identify aggravating factors among cardiac factors, non-cardiac comorbidities, and social factors. The aim of this study was to elucidate determinant factors of impaired QOL and clarify the association between QOL and prognosis in patients with HFpEF.

Methods and results

Patient data were extracted from The Prospective mUlticenteR obServational stUdy of patIenTs with Heart Failure with Preserved Ejection Fraction (PURSUIT HFpEF) study. EuroQol 5 dimensions 5-level (EQ-5D-5L) data were obtained at discharge to evaluate patients' health-related QOL. A total of 864 patients were enrolled in this study. Multivariable logistic regression analysis revealed that only non-cardiac factors such as age, female sex, frailty, malnutrition and inflammation were significantly associated with low EQ-5D-5L score, whereas cardiac factors showed no significant association after multivariable adjustment. A total of 206 patients died over a mean follow-up period of 2.0±1.2 years. Kaplan–Meier survival curve analysis demonstrated a significant increase in risk of mortality stratified by tertiles of EQ-5D-5L score (p<0.0001). Cox multivariable analysis revealed that patients with low EQ-5D-5L score had a significantly greater risk of mortality than those with high EQ-5D-5L score (adjusted hazard ratio: 2.20 (1.40–3.45), p=0.001).

Conclusion

Among patients with HFpEF, non-cardiac factors such as age, female sex, frailty, malnutrition and inflammation are significantly associated with impaired QOL. The QOL score itself also offers useful prognostic information in patients with HFpEF.

Funding Acknowledgement

Type of funding sources: None.

Insight into the relationship between heart rate and mortality in patients in sinus rhythm with heart failure with preserved ejection fraction

Background

There are several reports showing that elevated heart rate (HR) is associated with poor outcomes in patients in sinus rhythm (SR) with heart failure with preserved ejection fraction (HFpEF), although the association is weak or none in HFpEF patients with atrial fibrillation (Af). However, in previous studies, cardiac and non-cardiac factors which may be associated with elevated HR, have not been fully adjusted for.

Purpose

The purpose of this study is to explore covariates of elevated HR and to investigate the relationship between heart rate and mortality in HFpEF patients in SR.

Methods and results

Of the 1161 patients, who registered prospective multicenter, observational study of patients with HFpEF (PURSUIT-HFpEF), 726 patients in SR were examined. We performed laboratory testing and echocardiography in the compensated stage (in stable condition after treatment of acute decompensated HF). Geriatric nutritional risk index (GNRI) was calculated as nutrition index. Resting heart rate (HR) was analyzed as categorical (tertiles, T1–3). We followed the patients for median of 598 days (interquartile range 329–1028 days) to observe the outcome all-cause mortality.

The Kaplan analysis revealed that there was a significant difference between heart rate and mortality (log-rank, p=0.001). Characteristics were compared between patients in T1 (HR ≤63) and T3 (HR ≥75). There were no differences in cardiac factors between patients in T1 and T3. C-reactive protein (CRP) was significantly higher in patients in T3 than those in T1 (p=0.0004,). GNRI was significantly lower in patients in T3 than those in T1 (p=0.001). After adjustment for covariates including N-terminal pro-B type natriuretic peptide and estimated glomerular filtration rate, CRP and GNRI significantly correlated with HR (continuous variable) by multiple regression analysis (beta-coefficient = 1.52, p=0.003 and beta-coefficient = −0.14, p=0.04, respectively). Taking T1 as the reference, multivariable Cox regression analysis revealed that T3 was independently associated with mortality (hazard ratio: 2.10, 95% confidence interval: 1.33–3.32, p=0.001).

Conclusion

Although elevated HR was associated with enhanced inflammation and malnutrition, it itself was an independent predictor of death in HFpEF patients in SR.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Roche Diagnosis K.K.Fuji Film Toyama Chemical Co. Ltd.

Prognostic impact of the serial change of a systemic inflammation-nutrition index in patients with heart failure with preserved ejection fraction: insights from pursuit-hfpef registry

Background

Malnutrition and inflammation are associated with poor outcomes with heart failure (HF). It has been reported that advanced lung cancer inflammation index (ALI), calculated by body mass index × serum albumin level / neutrophil to lymphocyte ratio (NLR) can be useful for the risk stratification and predicting the post-discharge prognosis of the patients with acute decompensated heart failure (ADHF). However, there is no information available on the prognostic value of the serial ALI change in ADHF patients with preserved ejection fraction (HFpEF).

Methods and results

Patients' data were extracted from The Prospective mUlticenteR obServational stUdy of patIenTs with Heart Failure with Preserved Ejection Fraction (PURSUIT HFpEF) study, which is a prospective multicenter observational registry for ADHF-HFpEF in Osaka. Laboratory data and body weight measurements were performed at the discharge and 1 year after the discharge. We analyzed 527 patients after exclusion of patients on dialysis, in-hospital death, missing follow-up data, or missing data to calculate ALI. The study patients were categorized by the serial change from baseline to 1 year after the discharge (ΔALI) as follows: low tertile: ΔALI <−6.99 (n=176), middle tertile: −6.99 ≤ ALI <8.44 (n=176), and high tertile: 8.44 ≤ ΔALI (n=175). The endpoints of the present study were all-cause death (ACD) and cardiovascular death (CVD). During a mean follow-up period of 1.5±1.0 years, 94 patients had ACD and 40 patients had CVD. The Kaplan-Meier analysis revealed that the patients with middle and low ΔALI at 1 year after heart failure hospitalization had a significantly greater risk of reaching the ACD and CVD than those with high ΔALI (ACD: 22% vs 22% vs 10%, p=0.0011, CVD: 10% vs 9% vs 3%, p=0.014). On multivariate Cox analysis, ΔALI was significantly associated with ACD independently of age, gender, serum NT-proBNP level, and baseline ALI after adjustment for NYHA functional class, serum creatinine level, serum hemoglobin level, serum CRP level, serum sodium level and LVEF.

Conclusion

This study showed that patients with the increased ALI after the discharge had improved outcome in comparison to those without the increased ALI. The serial change of ALI, a systemic inflammation-nutrition index, might be useful for stratifying ADHF patients with HFpEF at risk for the total mortality and cardiovascular mortality.

Funding Acknowledgement

Type of funding sources: None.

Premature atrial contraction on Holter electrocardiogram predicts the recurrence of atrial fibrillation after catheter ablation

Introduction

It is important to detect the recurrence of atrial fibrillation (AF) after catheter ablation (CA) early, but the method of detection has not been established. The purpose of this study is to determine whether 24-h Holter electrocardiogram (ECG) can predict the recurrence of AF after CA.

Methods

We studied 336 patients of 497 patients enrolled in EARNEST-PVI trial to investigate whether the total number of premature atrial contraction (PAC) and the maximum number of PAC run by 24-h Holter ECG at 6 months after CA predicted AF recurrence after 6 months. We excluded 86 patients with recurrence by 6 months after CA and 75 patients without Holter ECG at 6 months after CA.

Results

Median age was 66 years, male were 77% and median follow-up period was 1138 days. Receiver operating characteristic curve analysis identified the total number of PAC ≥270 beats and the maximum number of PAC run ≥8 beats as the optimal cutoff for prediction of AF recurrence. Kaplan-Meier analysis showed patients with the total number of PAC ≥270 beats had more frequent AF recurrence than those without (Kaplan-Meier estimated 3-year AF recurrence rate 34% vs. 17%, Log-rank P=0.001) and patients with the maximum number of PAC run ≥8 beats had more frequent AF recurrence than those without (Kaplan-Meier estimated 3-year AF recurrence rate 33% vs. 20%, Log-rank P=0.006). Multivariate analysis revealed that the total number of PAC ≥270 beats and the maximum number of PAC run were significantly associated with AF recurrence (hazard ratio [95% confidence interval] 1.83 [1.16–2.91], P=0.01 and 1.01 [1.01–1.02], P=0.001, respectively)

Conclusion

The total number of PAC and the maximum number of PAC run on the Holter ECG may be useful in predicting AF recurrence after CA.

Funding Acknowledgement

Type of funding sources: None.

The seroprevalence of neutralizing antibodies against the adeno-associated virus capsids in Japanese hemophiliacs

Adeno-associated virus (AAV) vectors are promising modalities of gene therapy to address unmet medical needs. However, anti-AAV neutralizing antibodies (NAbs) hamper the vector-mediated therapeutic effect. Therefore, NAb prevalence in the target population is vital in designing clinical trials with AAV vectors. Hence, updating the seroprevalence of anti-AAV NAbs, herein we analyzed sera from 100 healthy individuals and 216 hemophiliacs in Japan. In both groups, the overall seroprevalence against various AAV serotypes was 20%–30%, and the ratio of the NAb-positive population increased with age. The seroprevalence did not differ between healthy participants and hemophiliacs and was not biased by the concomitant blood-borne viral infections. The high neutralizing activity, which strongly inhibits the transduction with all serotypes in vitro, was mostly found in people in their 60s or of older age. The multivariate analysis suggested that “60s or older age” was the only independent factor related to the high titer of NAbs. Conversely, a large proportion of younger hemophiliacs was seronegative, rendering them eligible for AAV-mediated gene therapy in Japan. Compared with our previous study, the peak of seroprevalences has shifted to older populations, indicating that natural AAV exposure in the elderly occurred in their youth but not during the last decade.

MAP KINASE PHOSPHATASE1 promotes osmotolerance by suppressing PHYTOALEXIN DEFICIENT4-independent immunity

Initial exposure of plants to osmotic stress caused by drought, cold, or salinity leads to acclimation, termed acquired tolerance, to subsequent severe stresses. Acquired osmotolerance induced by salt stress is widespread across Arabidopsis (Arabidopsis thaliana) accessions and is conferred by disruption of a nucleotide-binding leucine-rich repeat gene, designated ACQUIRED OSMOTOLERANCE. De-repression of this gene under osmotic stress causes detrimental autoimmunity via ENHANCED DISEASE SUSCEPTIBILITY1 and PHYTOALEXIN DEFICIENT4 (PAD4). However, the mechanism underlying acquired osmotolerance remains poorly understood. Here, we isolated an acquired osmotolerance-defective mutant (aod13) by screening 30,000 seedlings of an ion beam-mutagenized M2 population of Bu-5, an accession with acquired osmotolerance. We found that AOD13 encodes the dual-specificity phosphatase MAP KINASE PHOSPHATASE1 (MKP1), which negatively regulates MITOGEN-ACTIVATED PROTEIN KINASE3/6 (MPK3/6). Consistently, MPK3/6 activation was greater in aod13 than in the Bu-5 wild-type (WT). The aod13 mutant was sensitive to osmotic stress but tolerant to salt stress. Under osmotic stress, pathogenesis-related genes were strongly induced in aod13 but not in the Bu-5 WT. Loss of PAD4 in pad4 aod13 plants did not restore acquired osmotolerance, implying that activation of immunity independent of PAD4 renders aod13 sensitive to osmotic stress. These findings suggest that AOD13 (i.e. MKP1) promotes osmotolerance by suppressing the PAD4-independent immune response activated by MPK3/6.

Mitochondrial Fission Complex Is Required for Long-Term Heat Tolerance of Arabidopsis

Plants are often exposed not only to short-term (S) heat stress but also to long-term (L) heat stress over several consecutive days. A few Arabidopsis mutants defective in L-heat tolerance have been identified, but the molecular mechanisms involved are less well understood than those involved in S-heat tolerance. To elucidate the mechanisms, we isolated the new sensitive to long-term heat5 (sloh5) mutant from EMS-mutagenized seeds of L-heat-tolerant Col-0. The sloh5 mutant was hypersensitive to L-heat but not to S-heat, osmo-shock, salt-shock or oxidative stress. The causal gene, SLOH5, is identical to elongatedmitochondria1 (ELM1), which plays an important role in mitochondrial fission in conjunction with dynamin-related proteins DRP3A and DRP3B. Transcript levels of ELM1, DRP3A and DRP3B were time-dependently increased by L-heat stress, and drp3a drp3b double mutants were hypersensitive to L-heat stress. The sloh5 mutant contained massively elongated mitochondria. L-heat stress caused mitochondrial dysfunction and cell death in sloh5. Furthermore, WT plants treated with a mitochondrial myosin ATPase inhibitor were hypersensitive to L-heat stress. These findings suggest that mitochondrial fission and function are important in L-heat tolerance of Arabidopsis.

Impact of heart rate reduction on recurrence after catheter ablation of persistent atrial fibrillation

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Johnson & Johnson KK

OnBehalf

OCVC Arrhythmia Investigators

Background

Predicting heart rate (HR) after restoration of sinus rhythm (SR) remains one of the challenges when performing catheter ablation (CA) of persistent atrial fibrillation (AF).

Purpose

To evaluate the association between pre-ablation HR during AF and post-ablation HR during SR, and whether the HR reduction is associated with AF recurrence.

Methods

The analysis was performed from the EARNEST-PVI trial, a randomized controlled trial designed to assess a CA strategy for persistent AF, which was conducted in the Osaka region of Japan. After excluding patients with beta-blocker prescription, a total of 216 patients (median age, 67 years; 20% female; 23% long-standing persistent AF) with AF rhythm at baseline and SR at discharge were enrolled in this study. Baseline HR during AF and post-ablation HR during SR was measured on admission and at discharge using the 12-lead electrocardiograms, respectively.

Results

There was a mild correlation between baseline HR (median 82 [interquartile range 72-95] bpm) and post-ablation HR (78 [48-117] bpm) (r = 0.27, p <0.001). Reduction in HR was positively associated with baseline HR (r = 0.79, p <0.001) and was negatively associated with post-ablation HR (r = - 0.37, p <0.001). During the follow-up of 1 year, 56 patients (25.9%) experienced AF recurrence. HR reduction had the higher diagnostic accuracy in predicting AF recurrence than HR at baseline and HR after CA (area under the curve, 0.625; 95% confidence interval, 0.557–0.690; p = 0.003). AF recurrence rate was significantly higher in 141 patients with smaller HR reduction (cut-off, <14bpm) than those with larger HR reduction (31.9% vs. 14.7%, p = 0.009). After adjustment of age, gender, long-standing persistent AF, and CA strategy, HR reduction of <14 bpm was a significant predictor of AF recurrence (hazard ratio, 2.32; 95% confidence interval, 1.20–4.51; p = 0.013).

Conclusions

There was a mild correlation between HR during AF and HR after restoration of SR in patients underwent CA of persistent AF. HR reduction after restoration of SR predicted AF recurrence.

Differential regulations of abscisic acid-induced desiccation tolerance and vegetative dormancy by group B3 Raf kinases in liverworts

Phytohormone abscisic acid (ABA) plays a key role in stomata closure, osmostress acclimation, and vegetative and embryonic dormancy. Group B3 Raf protein kinases (B3-Rafs) serve as positive regulators of ABA and osmostress signaling in the moss Physcomitrium patens and the angiosperm Arabidopsis thaliana. While P. patens has a single B3-Raf called ARK, specific members of B3-Rafs among six paralogs regulate ABA and osmostress signaling in A. thaliana, indicating functional diversification of B3-Rafs in angiosperms. However, we found that the liverwort Marchantia polymorpha, belonging to another class of bryophytes, has three paralogs of B3-Rafs, MpARK1, MpARK2, and MpARK3, with structural variations in the regulatory domains of the polypeptides. By reporter assays of the P. patens ark line and analysis of genome-editing lines of M. polymorpha, we found that these B3-Rafs are functionally redundant in ABA response, with respect to inhibition of growth, tolerance to desiccation and expression of stress-associated transcripts, the majority of which are under the control of the PYR/PYL/RCAR-like receptor MpPYL1. Interestingly, gemmae in gemma cups were germinating only in mutant lines associated with MpARK1, indicating that dormancy in the gametophyte is controlled by a specific B3-Raf paralog. These results indicated not only conservation of the role of B3-Rafs in ABA and osmostress response in liverworts but also functional diversification of B3-Rafs, which is likely to have occurred in the early stages of land plant evolution.

KLU/CYP78A5, a Cytochrome P450 Monooxygenase Identified via Fox Hunting, Contributes to Cuticle Biosynthesis and Improves Various Abiotic Stress Tolerances

Acquired osmotolerance after salt stress is widespread among Arabidopsis thaliana (Arabidopsis) accessions. Most salt-tolerant accessions exhibit acquired osmotolerance, whereas Col-0 does not. To identify genes that can confer acquired osmotolerance to Col-0 plants, we performed full-length cDNA overexpression (FOX) hunting using full-length cDNAs of halophyte Eutrema salsugineum, a close relative of Arabidopsis. We identified EsCYP78A5 as a gene that can confer acquired osmotolerance to Col-0 wild-type (WT) plants. EsCYP78A5 encodes a cytochrome P450 monooxygenase and the Arabidopsis ortholog is known as KLU. We also demonstrated that transgenic Col-0 plants overexpressing AtKLU (AtKLUox) exhibited acquired osmotolerance. Interestingly, KLU overexpression improved not only acquired osmotolerance but also osmo-shock, salt-shock, oxidative, and heat-stress tolerances. Under normal conditions, the AtKLUox plants showed growth retardation with shiny green leaves. The AtKLUox plants also accumulated higher anthocyanin levels and developed denser cuticular wax than WT plants. Compared to WT plants, the AtKLUox plants accumulated significantly higher levels of cutin monomers and very-long-chain fatty acids, which play an important role in the development of cuticular wax and membrane lipids. Endoplasmic reticulum (ER) stress induced by osmotic or heat stress was reduced in AtKLUox plants compared to WT plants. These findings suggest that KLU is involved in the cuticle biosynthesis, accumulation of cuticular wax, and reduction of ER stress induced by abiotic stresses, leading to the observed abiotic stress tolerances.

ECERIFERUM 10 Encoding an Enoyl-CoA Reductase Plays a Crucial Role in Osmotolerance and Cuticular Wax Loading in Arabidopsis

Acquired osmotolerance induced after salt stress is widespread across Arabidopsis thaliana (Arabidopsis) accessions (e.g., Bu-5). However, it remains unclear how this osmotolerance is established. Here, we isolated a mutant showing an acquired osmotolerance-defective phenotype (aod2) from an ion-beam-mutagenized M2 population of Bu-5. aod2 was impaired not only in acquired osmotolerance but also in osmo-shock, salt-shock, and long-term heat tolerances compared with Bu-5, and it displayed abnormal morphology, including small, wrinkled leaves, and zigzag-shaped stems. Genetic analyses of aod2 revealed that a 439-kbp region of chromosome 4 was translocated to chromosome 3 at the causal locus for the osmosensitive phenotype. The causal gene of the aod2 phenotype was identical to ECERIFERUM 10 (CER10), which encodes an enoyl-coenzyme A reductase that is involved in the elongation reactions of very-long-chain fatty acids (VLCFAs) for subsequent derivatization into cuticular waxes, storage lipids, and sphingolipids. The major components of the cuticular wax were accumulated in response to osmotic stress in both Bu-5 WT and aod2. However, less fatty acids, primary alcohols, and aldehydes with chain length ≥ C30 were accumulated in aod2. In addition, aod2 exhibited a dramatic reduction in the number of epicuticular wax crystals on its stems. Endoplasmic reticulum stress mediated by bZIP60 was increased in aod2 under osmotic stress. The only cer10 showed the most pronounced loss of epidermal cuticular wax and most osmosensitive phenotype among four Col-0-background cuticular wax-related mutants. Together, the present findings suggest that CER10/AOD2 plays a crucial role in Arabidopsis osmotolerance through VLCFA metabolism involved in cuticular wax formation and endocytic membrane trafficking.

Characteristics and prognosis in heart failure with preserved ejection fraction patients without left ventricular hypertrophy

Background

Clinical heterogeneity exists in heart failure with preserved ejection fraction (HFpEF). Left ventricular (LV) structure in HFPEF is characterized by normal LV cavity size and LV hypertrophy (LVH). However some of HFPEF patients do not have LV hypertrophy, and these patients may have distinct characteristics,

Purpose

The purpose of this study is to clarify the clinical characteristics and the prognosis for HFPEF patients without LVH.

Methods

We studied 1097 patients, who were hospitalized for acute decompensated heart failure with LVEF ≥50%, and enrolled in the PURSUIT-HFpEF registry. Laboratory testing and echocardiography were examined in the compensated stage (in stable condition after treatment of acute decompensated HF). We divided these patients into 2 groups based on LV mass index (LVMI) in the compensated stage according to the American Society of Echocardiography/European Association of Cardiovascular Imaging recommendations; patients with LVH (48%) and those without LVH (52%).

Results

Patients without LVH had significantly lower levels of C-reactive protein and N-terminal pro brain natriuretic peptide (NT-proBNP) and higher levels of estimated glomerular filtration rate in the compensated stage than those with it (p<0.05 for all). Cox hazard regression analysis showed that absence of LVH was favorably associated with the primary composite endpoint of all-cause death, HF rehospitalization, and cerebrovascular events (hazard ratio 0.776, 95% confidence interval 0.620-to 0.970, p<0.05).

On the other hand, the frequency of atrial fibrillation (Af) in the decompensated stage was higher in patients without LVH than those with it (52.1% vs 39.3%, p<0.001). Multivariate logistic analysis showed that absence of LVH was independently associated with presence of Af in the decompensated stage (odds ratio=1.520, 95% confidence interval 1.130 to 2.050, P<0.01)

Conclusions

HFPEF patients without LVH have less organ damage and favorable prognosis. Af may play a role in the decompensation of HF in HFPEF patients without LVH.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Roche Diagnostics K.K. (Grant number: not applicable)Fuji Film Toyama Chemical Co., Ltd. (Grant number: not applicable)

Prediction of functional capacity by the HFA-PEFF score in patients with acute decompensated heart failure with preserved ejection fraction: a post-hoc analysis from the PURSUIT-HFpEF registry

Background

Diagnosing heart failure with preserved ejection fraction (HFpEF) is still challenging, and the H2FPEF- and the HFA-PEFF score were proposed as simple and reliable diagnostic tools. We recently reported that the HFA-PEFF score was significantly associated with the composite endpoint of all-cause death and heart failure readmission in patients with acute decompensated HFpEF (Sotomi. Eur J Heart Fail, in press).

Purpose

To investigate the relation whether the HFA-PEFF or H2FPEF score can evaluate functional capacity in patients with HFpEF

Methods

We calculated H2FPEF score and the second step of HFA-PEFF score among the registered patients in the PURSUIT-HFpEF (Prospective, Multicenter, Observational Study of Patients with Heart Failure with Preserved Ejection Fraction) study, which is a multicenter registration of patients hospitalized for acute decompensated HFpEF. We performed 6 minute walk (6MW) test and measured NT-proBNP before discharge. We followed the study patients for median of 360 days (IQR 237–630 days) to observe the major adverse cardiovascular events (MACE; composite of death, heart failure hospitalization and stroke).

Results

We enrolled 757 patients (age 81±9 years, male gender 45%) hospitalized for acute decompensated HFpEF for the present study. The H2FPEF score was obtained in 588 (77.7%) patients and all patients had ≥2 points. The HFA-PEFF score was obtained in 615 (81.2%) patients, though global longitudinal strain was not available. We divided these patients into 3 groups based on the HFA-PEFF score (score 2 to 4, 5, and 6) or on the H2FPEF score (score 0 to 3, 4 to 5 and 6 to 8). There were a significant difference in NT-pro BNP between 3 groups based on HFA-PEFF score (p=0.01, Table 1), and patients with score 6 had significantly higher NT-proBNP than those with score 2 to 4 (p=0.02). A significant difference was observed in 6MW distance among these groups (p=0.04, Table), and those with score 6 had significantly shorter distance than those with score 2 to 4 (p=0.04). Cox proportional hazard model selected HFA-PEFF score as a significant predictor for MACE, and Kaplan-Meier survival analysis demonstrated that classification of HFA-PEFF score significantly stratified the patients' risk for MACE. On the other hand, there was no significant difference in 6MW distance among 3 groups based on H2FPEF score (p=0.53), and H2FPEF score was not an independent predictor for MCE by the Cox model analysis. Moreover, the lowest H2PEF score group had higher NT-proBNP than other 2 groups (p=0.02)

Conclusions

The HFA-PEFF score predicted functional capacity as well as prognosis in patients hospitalized for HFpEF, while the H2PEF score did not.

Funding Acknowledgement

Type of funding sources: None. Table 1

Reappraising the role of baseline plasma C-reactive protein levels on recurrence after catheter ablation of persistent atrial fibrillation: insight from EARNEST-PVI trial

Background

Subclinical inflammation is an important pathogenesis of developing and sustaining atrial fibrillation (AF). Because AF itself contribute to the inflammatory response, the role of baseline subclinical inflammation on AF recurrence after catheter ablation (CA) remains controversial in patients with persistent AF.

Purpose

To evaluate whether baseline plasma C-reactive protein (CRP) levels, a sensitive marker of inflammation, are associated with AF recurrence following CA.

Methods

The analysis was performed from the EARNEST-PVI trial, a randomized controlled trial designed to assess a CA strategy for persistent AF, which was conducted in the Osaka region of Japan. A total of 441 patients (median age, 67 years; 26% female; 25% long-standing persistent AF) whose plasma CRP levels were measured at baseline were included in this study.

Results

At baseline, a median (interquartile range) of plasma CRP level was 0.10 [0.06–0.19] mg/dl. Plasma CRP levels significantly increased at discharge (0.83 [0.21–1.84] mg/dl, p<0.001) and decreased 1 year after CA (0.10 [0.05–0.20] mg/dl, p=0.040) compared to the baseline value. During the follow-up of 1 year, 115 patients (26%) experienced AF recurrence, and the incidence was significantly higher in 124 patients with low CRP levels at baseline (cut-off ≤0.06 mg/dl) than the other 317 patients (33.9% vs. 23.0%, p=0.017). After adjustment of age, gender, body mass index, long-standing persistent AF, CA strategy, and plasma brain natriuretic peptide levels, low plasma CRP levels was a significant predictor of AF recurrence (hazard ratio, 1.51; 95% confidence interval, 1.02–2.24; p=0.042).

Conclusions

Low plasma CRP levels at baseline predicted AF recurrence in the EARNEST-PVI trial. Reappraising the role of CRP on AF recurrence may be needed in patients with persistent AF.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Johnson & Johnson KK

Renal function and arrhythmia outcomes in persistent atrial fibrillation patients after catheter ablation: subanalysis of the EARNEST-PVI trial

Background

Atrial fibrillation (AF) reduces the renal function. Renal dysfunction and AF often coexist. Catheter ablation (CA) of persistent AF can maintain a sinus rhythm and may improve the renal function.

Purpose

We sought to elucidate whether the estimated glomerular filtration rate (eGFR) in patients with persistent AF was increased after CA, especially with the presence of an AF recurrence.

Methods

We enrolled 487 persistent AF patients whose eGFR data were available both before and 1-year after the CA out of 512 patients in the EARNEST-PVI trial.

Results

The mean age was 65±9 year and 113 patients (24.8%) had long-standing persistent AF. We compared the eGFR at baseline with that 1-year after the CA. AF recurrences were recognized in 118 patients (25.8%). The eGFR was similar between the group without recurrence and that with recurrence at baseline (without AF recurrence vs. with AF recurrence; 63.8±14.3 vs. 62.7±13.6 mL/min/1.73m2, p=0.46). In patients without AF recurrence, the G1, G2, G3a, G3b, G4, and G5 were 13 (3.8%), 198 (58.4%), 98 (28.9%), 26 (7.7%), 3 (0.9%), and 1 (0.3%), respectively at baseline. In the patients with AF recurrence, the G1, G2, G3a, G3b, G4, and G5 were 3 (2.5%), 68 (57.8%), 38 (32.2%), 6 (5.1%), 3 (2.5%), and 0 (0%), respectively at baseline. The ΔeGFR was significantly higher in the patients without AF recurrence than in those with AF recurrence (without AF recurrence vs. with AF recurrence; 5.1 [−0.3, 10.8] vs. 3.0 [−3.0, 7.6], p=0.0033). In the patients without AF recurrence, a better eGFR class at 1-year after the CA than in those before the CA was recognized in 75 patients (22.1%), while it was recognized in 19 patients (16.1%) with AF recurrences.

Conclusion

Successful catheter ablation in patients with persistent AF led to a better renal outcome.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): This study was funded by Medtronic, Johnson & Johnson, and Abbott.

The impact of substrate and trigger ablation for reduction of functional mitral regurgitation in patients with persistent atrial fibrillation

Background

Functional mitral regurgitation (FMR) is not uncommon in atrial fibrillation (AF) patients. Left atrial (LA) substrate remodeling and corresponding mitral valve annulus dilation has been reported as the most possible cause of FMR. Percutaneous catheter ablation (CA) is an effective treatment for AF. Although significant FMR could be improved by sinus restoration, patients with mitral regurgitation were more likely to experience recurrent AF post ablation, especially those with significant mitral regurgitation. There is no information available on the efficacy of CA for persistent AF in patients with FMR.

Purpose

The purpose of this study is to investigate the predictors of FMR improvement by CA and to determine the efficacy of substrate and trigger CA for persistent AF in patients with FMR.

Methods

We prospectively studied 512 consecutive patients admitted for persistent AF ablation from the EARNEST-PVI (Prospective Multicenter Randomized Study of Effect of Extensive Ablation on Recurrence in Patients with Persistent Atrial Fibrillation Treated with Pulmonary Vein Isolation) trial.

On admission, enrolled patients were randomly assigned in a 1:1 ratio to pulmonary vein isolation (PVI) or PVI-plus additional ablation (linear ablation or/and CFAE ablation). Of the 512 patients, we studied 94 patients with preoperative echocardiography showing moderate or greater baseline FMR. FMR grades were classified into 5 grades (0/1/2/3/4). The FMR improvement group (FMRI(+)) was defined as a case in which the FMR was improved by two or more grades compared the preoperative echocardiography and the one year follow-up examination.

Results

Of the 94 patients, 42 were in the PVI group and 52 were in the PVI-plus additional ablation group. There were 30 cases in the FMRI(+) group and 64 cases in the FMRI(−) group. There were no significant baseline differences in age, sinus rhythm maintenance, plasma B-type natriuretic peptide (BNP) level, left ventricular diastolic dimension, or left atrium dimension between the FMRI(+) and FMRI(−) groups. AF duration was significantly shorter in the FMRI(+) group than FMRI(−) groups (5.8±9.4 months vs 12.4±15.4 months, p<0.0001). In addition, significantly more additional ablation cases were observed in the FMRI(+) group than in the FMRI(−) group (73.3% vs 46.8%, p=0.016). In multivariate analyses, only additional ablation was an independent predictor of FMRI (odds ratio 0.226 95% CI 0.081–0.626; p=0.004).

Conclusions

Catheter ablation is a valid option for the treatment of AF in patients with functional MR and additional substrate and trigger ablation were the only independent predictor of FMR improvement.

Funding Acknowledgement

Type of funding sources: None.

Differences in quality of life improvement with pulmonary vein isolation alone vs. more extensive ablation of persistent atrial fibrillation: insights from the EARNEST-PVI trial

Background

Improving the quality of life (QoL) is one of the main purposes of catheter ablation (CA) of persistent atrial fibrillation (AF). QoL improvement in persistent AF patients has not been fully clarified. The EARNEST-PVI trial was a multi-center randomized trial comparing clinical outcomes of pulmonary vein isolation (PVI) alone and more intensive ablation in addition to PVI including complex fractionated atrial electrogram (CFAE) and linear ablation (PVI plus).

Purpose

To investigate the QoL change after persistent AF ablation and the differences between the PVI-alone strategy and the PVI plus strategy.

Methods

In the EARNEST-PVI trial, patients with persistent AF who underwent an initial catheter ablation (n=512) were randomly assigned in a 1:1 ratio to either PVI alone or PVI plus. Quality of life was assessed at baseline and at 12 months after ablation for AF using the 36-Item Short Form Health Survey. Scores were also converted to a physical health component summary (PCS), a mental health component summary (MCS) and a role/social component summary (RCS).

Results

In the EARNEST-PVI trial, the PVI alone strategy was associated with higher recurrence rate compared with the PVI plus additional ablation strategy. After excluding 68 patients for whom preoperative or postoperative QoL assessment was not available, 222 patients were evaluated respectively. Overall, significant improvements in PCS (46.2±11.4 to 48.7±11.4]), MCS (50.1±8.8 to 54.3±8.6) and RCS (44.6±13.3 to 48.6±11.3) occurred 12 months after ablation (P<0.001, respectively). Although significant QoL improvement occurred in both PVI alone and PLI plus strategies, the changes in PCS was greater in the PVI-plus than that in PVI-alone (3.5±10.3 vs 1.5±10.6, P=0.04).

Conclusions

Ablation for persistent atrial fibrillation improved both physical and mental quality of life. The PVI-plus strategy showed greater improvement in physical QoL.

Funding Acknowledgement

Type of funding sources: None. QoL improvement

Characterization and visualization of murine coagulation factor VIII-producing cells in vivo

Coagulation factors are produced from hepatocytes, whereas production of coagulation factor VIII (FVIII) from primary tissues and cell species is still controversial. Here, we tried to characterize primary FVIII-producing organ and cell species using genetically engineered mice, in which enhanced green fluorescent protein (EGFP) was expressed instead of the F8 gene. EGFP-positive FVIII-producing cells existed only in thin sinusoidal layer of the liver and characterized as CD31^high, CD146^high, and lymphatic vascular endothelial hyaluronan receptor 1 (Lyve1)⁺. EGFP-positive cells can be clearly distinguished from lymphatic endothelial cells in the expression profile of the podoplanin⁻ and C-type lectin-like receptor-2 (CLEC-2)⁺. In embryogenesis, EGFP-positive cells began to emerge at E14.5 and subsequently increased according to liver maturation. Furthermore, plasma FVIII could be abolished by crossing F8 conditional deficient mice with Lyve1-Cre mice. In conclusion, in mice, FVIII is only produced from endothelial cells exhibiting CD31^high, CD146^high, Lyve1⁺, CLEC-2⁺, and podoplanin⁻ in liver sinusoidal endothelial cells.

An ER-Golgi Tethering Factor SLOH4/MIP3 Is Involved in Long-Term Heat Tolerance of Arabidopsis

Plants are often exposed not only to short-term (S-) heat stress but also to diurnal long-term (L-) heat stress over several consecutive days. To reveal the mechanisms underlying L-heat stress tolerance, we here used a forward genetic screen for sensitive to long-term heat (sloh) mutants and isolated sloh4. The mutant was hypersensitive to L-heat stress but not to S-heat stress. The causal gene of sloh4 was identical to MIP3 encoding a member of the MAIGO2 (MAG2) tethering complex, which is composed of the MAG2, MIP1, MIP2 and MIP3 subunits and is localized at the endoplasmic reticulum (ER) membrane. Although sloh4/mip3 was hypersensitive to L-heat stress, the sensitivity of the mag2-3 and mip1-1 mutants was similar to that of the wild type (WT). Under L-heat stress, the ER stress and the following unfolded protein response (UPR) were more pronounced in sloh4 than in the WT. Transcript levels of bZIP60-regulated UPR genes were strongly increased in sloh4 under L-heat stress. Two processes known to be mediated by INOSITOL REQUIRING ENZYME1 (IRE1) - accumulation of the spliced bZIP60 transcript and a decrease in the transcript levels of PR4 and PRX34, encoding secretory proteins - were observed in sloh4 in response to L-heat stress. These findings suggest that misfolded proteins generated in sloh4 under L-heat stress may be recognized by IRE1 but not by bZIP28, resulting in the initiation of the UPR via activated bZIP60. Therefore, it would be possible that only MIP3 in the MAG2 complex has an additional function in L-heat tolerance, which is not related to the ER-Golgi vesicle tethering.

Activation of SnRK2 by Raf-like kinase ARK represents a primary mechanism of ABA and abiotic stress responses

The Raf-like protein kinase abscisic acid (ABA) and abiotic stress-responsive Raf-like kinase (ARK) previously identified in the moss Physcomitrium (Physcomitrella) patens acts as an upstream regulator of subgroup III SNF1-related protein kinase2 (SnRK2), the key regulator of ABA and abiotic stress responses. However, the mechanisms underlying activation of ARK by ABA and abiotic stress for the regulation of SnRK2, including the role of ABA receptor-associated group A PP2C (PP2C-A), are not understood. We identified Ser1029 as the phosphorylation site in the activation loop of ARK, which provided a possible mechanism for regulation of its activity. Analysis of transgenic P. patens ark lines expressing ARK-GFP with Ser1029-to-Ala mutation indicated that this replacement causes reductions in ABA-induced gene expression, stress tolerance, and SnRK2 activity. Immunoblot analysis using an anti-phosphopeptide antibody indicated that ABA treatments rapidly stimulate Ser1029 phosphorylation in the wild type (WT). The phosphorylation profile of Ser1029 in ABA-hypersensitive ppabi1 lacking protein phosphatase 2C-A (PP2C-A) was similar to that in the WT, whereas little Ser1029 phosphorylation was observed in ABA-insensitive ark missense mutant lines. Furthermore, newly isolated ppabi1 ark lines showed ABA-insensitive phenotypes similar to those of ark lines. Therefore, ARK is a primary activator of SnRK2, preceding negative regulation by PP2C-A in bryophytes, which provides a prototype mechanism for ABA and abiotic stress responses in plants.

Decoding ABA and osmostress signalling in plants from an evolutionary point of view

The plant hormone abscisic acid (ABA) is fundamental for land plant adaptation to water-limited conditions. Osmostress, such as drought, induces ABA accumulation in angiosperms, triggering physiological responses such as stomata closure. The core components of angiosperm ABA signalling are soluble ABA receptors, group A protein phosphatase type 2C and SNF1-related protein kinase2 (SnRK2). ABA also has various functions in non-angiosperms, however, suggesting that its role in adaptation to land may not have been angiosperm-specific. Indeed, among land plants, the core ABA signalling components are evolutionarily conserved, implying their presence in a common ancestor. Results of ongoing functional genomics studies of ABA signalling components in bryophytes and algae have expanded our understanding of the evolutionary role of ABA signalling, with genome sequencing uncovering the ABA core module even in algae. In this review, we describe recent discoveries involving the ABA core module in non-angiosperms, tracing the footprints of how ABA evolved as a phytohormone. We also cover the latest findings on Raf-like kinases as upstream regulators of the core ABA module component SnRK2. Finally, we discuss the origin of ABA signalling from an evolutionary perspective.

Validation of the HFA-PEFF- and H2FPEF score in Japanese patients with heart failure with preserved ejection fraction

Background

Diagnosing heart failure with preserved ejection fraction (HFpEF) still remains challenging, and simple and reliable diagnostic tools have been required. Recently, novel and evidence-based diagnostic algorithms for HFpEF were proposed, such as H2FPEF score (Circulation. 2018) and HFA-PEFF score (Eur Heart J 2019), and their accuracy was validated in the outside patient group. However, there are regional and ethnic variations in patient characteristics of HFpEF, particularly between Western and Asian countries, and it is not elucidated whether these diagnostic scores are useful in Asian population.

Purpose

To investigate the validity of the HFA-PEFF- and H2FPEF score in Japanese patients with HFpEF.

Methods

We calculated H2FPEF score and the second step of HFA-PEFF score among the registered patients in the PURSUIT-HFpEF (Prospective, Multicenter, Observational Study of Patients with Heart Failure with Preserved Ejection Fraction) study, which is a multicenter registration of patients hospitalized for HFpEF. The obtained scores were compared with the scores of the HFpEF cohort in the previous validation studies. We followed the study patients for median of 360 days (IQR 237–630 days) to observe the major adverse cardiovascular events (MACE; composite of death, heart failure hospitalization and stroke).

Results

We enrolled 757 patients hospitalized for HFpEF between June 2016 and August 2019 for the present study. H2FPEF score was obtained in 588 (77.7%) patients among them. Compared with the HFpEF cohorts in the previously reported sub-analysis of TOPCAT trial, the PURSUIT-HFpEF cohort had lower mean value of HFpEF score (4.0±1.8 points vs. 6.0±2.0 points in Americans or 5.3±1.9 points in Russians). It had significantly higher proportion (40.3%, p<0.001) of patients in the low likelihood of HFpEF category (0–3 points) than the TOPCAT cohorts (8.0% in Americans and 19.6% in Russians).

HFA-PEFF score was obtained in 615 (81.2%) patients, though global longitudinal strain was not available. The mean value of HFA-PEFF score was 5.0±0.8, and all patients had ≥2 points. The proportion of patients in the high likelihood of HFpEF category (5–6 points) was 88.3%, which was significantly higher (p<0.001) than those of the HFpEF cohort from Europe and USA in the previous validation study (Eur J Heart Fail 2019). There was no correlation between H2FPEF score and HFA-PEFF score (R=0.06, p=0.14). Cox proportional hazard model selected HFA-PEFF score as a significant predictor for MACE during follow-up period, whereas H2PEF score was not selected. Kaplan-Meier survival analysis demonstrated that patients with 6 points of HFA-PEFF score had higher incidence rate of MACE than those with ≤5 points (p=0.002).

Conclusion

The HFA-PEFF score could be more useful for the diagnosis and risk stratification for HFpEF than the H2PEF score in the Japanese cohort.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Roche Diagnostics K.K.; Fuji Film Toyama Chemical Co. Ltd.

CATALASE2 plays a crucial role in long-term heat tolerance of Arabidopsis thaliana

Plants are often exposed not only to short-term (S-) heat stress but also to diurnal long-term (L-) heat stress over several consecutive days; nevertheless, most previous studies of heat tolerance have used S-heat stress, such as 42 °C for 30-60 min, for evaluation. Yet the mechanisms underlying L-heat tolerance remain poorly understood. Here we found that hydrogen peroxide (H₂O₂) in Arabidopsis thaliana plants increased time-dependently under L-heat stress (37 °C, 5 days) but not under S-heat stress (42 °C, 40 min). To reveal the contribution of reactive oxygen species (ROS) scavenging to heat tolerance, we evaluated the heat tolerance of ROS mutants. Only cat2 mutants, in which catalase (CAT) activity is defective, were hypersensitive to L-heat stress, but they were S-heat tolerant. We further revealed that (1) CAT2 was induced by L-heat stress but not by S-heat stress; (2) H₂O₂ accumulated highly in cat2 under L-heat stress, but not in cat1, cat3, or wild type; and (3) CAT activity was significantly reduced in cat2 under both normal and L-heat conditions. These results suggest that ROS scavenging is responsible for L-heat tolerance, and CAT2 plays a crucial role. On the other hand, since overexpression of CAT2 in wild-type plants did not enhance L-heat tolerance, CAT2 activity is necessary but insufficient for increasing L-heat tolerance.

Impact of simple nutrition index on the long-term mortality of acute decompensated heart failure patients with preserved left ventricular ejection fraction: insight from PURSUIT-HFpEF registry

Background

The novel nutrition index; triglyceride (TG) × total cholesterol (TG) × body weight (BW) index (TCBI) has been reported to be an easy and useful predictor for patients with coronary artery disease. However, there is no information available on the prognostic value of TCBI in patients with heart failure with preserved LVEF (HFpEF) who admitted with acute decompensated heart failure (ADHF).

Methods and results

Data were extracted from The Prospective mUlticenteR obServational stUdy of patIenTs with Heart Failure with Preserved Ejection Fraction (PURSUIT HFpEF) study. PURSUIT-HFpEF study is a prospective multicenter observational study in which collaborating hospitals recorded clinical, echocardiographic, and outcome data of ADHF pts with HFpEF. We enrolled consecutive 757 HFpEF patients who admitted with ADHF from June 2016 to June 2019. TCBI was calculated by the formula; TG × TC × BW / 1000 at the discharge. After we excluded patients with in-hospital death or without sufficient data, we analyzed 419 patients. The primary endpoint was all-cause mortality. During a median follow up period of 1.1 (0.9–1.9) years, 59 patients died. ROC analysis revealed that TCBI at discharge was a fair discriminator for predicting all-cause mortality (AUC 0.676, sensitivity 53%, specificity 78%). Multivariate Cox proportional analysis showed that TCBI (p=0.002) was an independent predictor for all cause death after adjustment with major confounders such as age, gender, NT-proBNP, hemoglobin and serum creatinine level. We divided patients into 4 groups according to quartiles of TCBI. Kaplan-Meier analysis showed a significantly higher risk of all-cause death in relation to the decrease in TCBI.

Conclusion

TCBI, a simple and novel nutrition index, is a useful and strong long-term prognostic indicator in ADHF patients with HFpEF.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Roche Diagnositics K.K.; Fuji Film Toyoma Chemical Co. Ltd.