Strategic validation of variants of uncertain significance in ECHS1 genetic testing

BACKGROUND

Enoyl-CoA hydratase short-chain 1 (ECHS1) is an enzyme involved in the metabolism of branched chain amino acids and fatty acids. Mutations in the ECHS1 gene lead to mitochondrial short-chain enoyl-CoA hydratase 1 deficiency, resulting in the accumulation of intermediates of valine. This is one of the most common causative genes in mitochondrial diseases. While genetic analysis studies have diagnosed numerous cases with ECHS1 variants, the increasing number of variants of uncertain significance (VUS) in genetic diagnosis is a major problem.

METHODS

Here, we constructed an assay system to verify VUS function for ECHS1 gene. A high-throughput assay using ECHS1 knockout cells was performed to index these phenotypes by expressing cDNAs containing VUS. In parallel with the VUS validation system, a genetic analysis of samples from patients with mitochondrial disease was performed. The effect on gene expression in cases was verified by RNA-seq and proteome analysis.

RESULTS

The functional validation of VUS identified novel variants causing loss of ECHS1 function. The VUS validation system also revealed the effect of the VUS in the compound heterozygous state and provided a new methodology for variant interpretation. Moreover, we performed multiomics analysis and identified a synonymous substitution p.P163= that results in splicing abnormality. The multiomics analysis complemented the diagnosis of some cases that could not be diagnosed by the VUS validation system.

CONCLUSIONS

In summary, this study uncovered new ECHS1 cases based on VUS validation and omics analysis; these analyses are applicable to the functional evaluation of other genes associated with mitochondrial disease.

Impact of measuring heteroplasmy of a pathogenic mitochondrial DNA variant at the single-cell level in individuals with mitochondrial disease

Pathogenic mitochondrial DNA heteroplasmy has mainly been assessed with bulk sequencing in individuals with mitochondrial disease. However, the distribution of heteroplasmy at the single-cell level in skin fibroblasts obtained from individuals, together with detailed clinical and biochemical information, remains to be investigated. We used the mitochondrial DNA single-cell assay for the transposase-accessible chromatin sequencing method. Skin fibroblasts were obtained from six individuals with mitochondrial disease and pathogenic m.3243A>G variants of differing severity. Different distributions of heteroplasmy at the single-cell level were identified in skin fibroblasts from all six individuals. Four individuals with different outcomes showed similar averaged heteroplasmy rates with normal mitochondrial respiratory chain enzyme activity, while the distribution of single-cell heteroplasmy patterns differed among the individuals. This study showed different heteroplasmy distribution patterns at the single-cell level in individuals with the m.3243A>G variant, who had a similar averaged heteroplasmy rates with normal mitochondrial respiratory chain enzyme activity. Whether such different heteroplasmy distribution patterns explain the different clinical outcomes should be assessed further in future studies. Measuring heteroplasmy of pathogenic mitochondrial DNA variants at the single-cell level could be important in individuals with mitochondrial disease.

Prognostic impact of acute kidney injury following tricuspid transcatheter edge-to-edge repair

Background

A considerable risk of acute kidney injury (AKI) following transcatheter interventions without iodinated contrast agents has also been recognized; however, little is known about the incidence and clinical relevance of post-procedural AKI in patients undergoing transcatheter edge-to-edge repair (TEER) for tricuspid regurgitation (TR).

Purpose

This study aimed to investigate the prognostic impact and predictors of post-procedural AKI following TEER for TR.

Methods

We retrospectively analyzed 218 consecutive patients who underwent TEER for TR. Post-procedural AKI was defined as an increase in serum creatinine of ≥0.3 mg/dl within 48 hours or of ≥50% within seven days after the procedure, compared to baseline. Procedural success was defined as at least one grade reduction in TR severity upon discharge. We determined the association between post-procedural AKI and the composite outcome consisting of all-cause mortality and re-hospitalization due to heart failure within one year after the procedure.

Results

Overall, the mean age of the patients was 79±7 years, and 46.3% of the patients were male. Post-procedural AKI occurred in 32 patients (14.7%) (Figure 1). Among baseline characteristics, male sex and an estimated glomerular filtration rate of <60 ml/min/m2 were associated with the occurrence of AKI. In addition, patients without procedural success had a higher incidence of post-procedural AKI (30.4% vs. 1.8%; p=0.024).

Patients with AKI had a higher incidence of in-hospital mortality compared to those without AKI (12.5% vs. 1.1%; p=0.005). Moreover, AKI was associated with the incidence of the composite outcome within one year after TEER for TR (adjusted hazard ratio: 2.06; 95% confidence interval: 1.11–3.84; p=0.023). In addition, our restricted cubic spline curve showed that a post-procedural increase in the creatinine level within seven days after the procedure was associated with a linear trend of the risk of the composite outcome after TEER (Figure 2).

Conclusions

Post-procedural AKI occurred in 14.7% of patients undergoing TEER for TR, despite the absence of iodinated contrast agents, which was associated with worse clinical outcomes. Male sex and CKD at baseline were related to the occurrence of AKI, and the procedural success of TEER was associated with a lower incidence of AKI. Our findings highlight the clinical impact of AKI following TEER for TR and should help with identifying patients at high risk of AKI.

Funding Acknowledgement

Type of funding sources: None.

Effectiveness of transcatheter edge-to-edge repair for atrial secondary mitral regurgitation

Background

Atrial secondary mitral regurgitation (ASMR) is a subtype of SMR that is characterized by normal left ventricular (LV) function, an enlarged left atrium and mitral annulus, and flattened leaflets. This anatomical feature is different from ventricular SMR (VSMR) and might therefore impact the procedural results of transcatheter edge-to-edge repair (TEER). The effectiveness and durability of TEER in patients with ASMR has not yet been well-studied.

Purpose

This study aimed to investigate the effectiveness of TEER and anatomical characteristics related to optimal MR reduction in patients with ASMR.

Methods

We retrospectively analyzed consecutive patients who underwent MitraClip at our institution. ASMR was defined as cases that met all of the following criteria: 1) normal mitral leaflets without organic disorder, 2) LV ejection fraction >50%, and 3) absence of LV enlargement and segmental abnormality. The primary outcome measure was MR reduction to ≤1+, and its predictors were explored in a logistic regression analysis. Leaflet-to-annulus index (LAI) was measured using the mid-esophageal long-axis view in the A2-P2 segment as follows: (anterior leaflet length + posterior leaflet length) / anteroposterior length of the mitral annulus.

Results

Among 415 patients with SMR, 118 patients met the criteria for ASMR (mean age: 80±8 years; male: 39.8%) (Figure 1). Patients with ASMR had a larger mitral annulus diameter, shorter mobile posterior leaflet length, and smaller coaptation depth compared to those with VSMR.

The technical success rate was 90.7%, and the MR reduction to ≤1+ after TEER was achieved in 94 (79.7%) patients with ASMR, which was comparable with VSMR. The in-hospital mortality rate was 2.5%. In multivariable logistic analysis, a large left-atrial (LA) volume index and a low LAI were associated with a lower rate of MR reduction to ≤1+ after TEER for ASMR (odds ratio [OR]: 0.98; 95% confidence interval [CI]: 0.97–0.99, and OR per 0.1 increase: 1.98; 95% CI: 1.13–3.45, respectively). The combined assessment of the LA volume index and LAI stratified the risk of residual MR ≥2+ after TEER (Figure 2).

In addition, the use of a newer generation of the MitraClip systems (NTR/XTR or G4 systems) was associated with a higher rate of MR reduction to ≤1+ compared to older generations (OR: 4.65; 95% CI: 1.67–13.00).

Conclusions

TEER with the MitraClip system achieved a high rate of MR reduction to ≤1+ in patients with ASMR. Furthermore, the new generations of the MitraClip system may provide a more effective reduction in ASMR. Although our findings suggest that TEER with the MitraClip system is a safe and feasible approach in patients with ASMR, the combined assessment of the LA volume index and LAI might be useful to refine the device selection for transcatheter mitral valve treatment in this subgroup of SMR patients.

Funding Acknowledgement

Type of funding sources: None.

Right ventricular ejection fraction assessed by computed tomography in patients undergoing transcatheter tricuspid valve intervention

Background

The role of right-ventricular (RV) function in patients with tricuspid regurgitation (TR) undergoing transcatheter tricuspid valve interventions (TTVI) is poorly understood. Although cardiac computed tomography (CCT) provides elaborate three-dimensional (3D) visualization of the entire anatomy of the RV and theoretically allows to assess the global RV systolic function. Nevertheless, the utility of the functional assessments of the RV using CCT remains unclear in patients undergoing TTVI.

Purpose

This study investigated the association of right-ventricular ejection fraction (RVEF) assessed by CCT with clinical outcome in patients undergoing TTVI.

Methods

We retrospectively assessed 3D-RVEF by using pre-procedural CCT images in patients undergoing TTVI with either edge-to-edge repair or annuloplasty device. RV dysfunction (RVD) was defined as a CT-RVEF <45%. The primary outcome was a composite outcome, consisting of all-cause mortality and hospitalization due to heart failure, within one year after TTVI.

Results

Of 157 patients, 58 (36.9%) presented with CT-RVEF <45%. Patients with CT-RVEF <45% were more likely to be male, to have a previous history of coronary artery disease, and had higher EuroSCORE II and a lower LVEF compared to those with CT-RVEF ≥45%, while the severity of TR was comparable between the groups.

Among the patients with CT-RVEF <45%, acute procedural success was achieved in 93.1%, and in-hospital mortality was 1.7%, which were comparable to those with CT-RVEF ≥45%.

Patients with CT-RVEF <45% had an improvement in New York Heart Association functional class at follow-up compared to baseline; however, CT-RVEF <45% was associated with a higher risk of the composite outcome (adjusted hazard ratio: 3.23; 95% confidence interval: 1.52–6.88; p=0.002) (Figure 1). Furthermore, CT-RVEF had an additional value to stratify the risk of the composite outcome beyond two-dimensional transthoracic echocardiographic (TTE) assessments (Figure 2).

In addition, patients with CT-RVEF <45% exhibited an attenuated association between a reduction in TR to <3+ and a lower incidence of the composite outcome after TTVI compared to those with CT-RVEF ≥45%.

Conclusions

TTVI is safe and feasible regardless of baseline RV function, while RVD, defined as 3D-RVEF <45%, is associated with a higher risk of the composite outcomes within one year after TTVI. Furthermore, our findings suggest that the prognostic benefits of TR reduction might be attenuated in patients with RVD. Given the additional prognostic value of CT-RVEF to the conventional echocardiographic assessments, the assessments of 3D-RVEF with CCT may refine the patient selection for TTVI.

Funding Acknowledgement

Type of funding sources: None.

Refining the accuracy of right ventricular-pulmonary arterial coupling in patients undergoing transcatheter tricuspid valve treatment

Background

Assessing right-ventricular (RV) function is paramount for risk stratification but remains challenging in patients with TR. RV-pulmonary artery (PA) coupling seems more feasible for the assessment of RV function.

Methods

We assessed RV-PA coupling by the ratio of TAPSE and PASP at baseline, in which PASP was measured both by echocardiography (ePASP) and invasively using a right-heart catheter (iPASP). We also assessed the RV fractional-area change (RVFAC) as measured by transthoracic echocardiography. Participants for the present study comprised patients undergoing TTVR from June 2015 to July 2021 at the University Hospital of Bonn. Patients lacking either echocardiographic or invasive measurements for the assessment of RV-PA coupling were excluded from the analysis. The outcome was defined as a composite of mortality and rehospitalization due to heart failure within one year after the procedure.

Results

A total of 206 patients were included in the present analysis. The participants were at an advanced age (78.5±7.1 years), predominantly female (58.3%), and at a high risk for surgery (EuroSCORE II: 7.4±4.8%). Massive/torrential TR was observed in 100 of these patients. With the median follow-up duration of 201 days (interquartile range 98–424 days), the outcome occurred in 57 patients. Compared to TAPSE/ePASP, TAPSE/iPASP showed better predictability for the outcome: the AUCs were 0.582 for TAPSE/ePASP and increased to 0.714 when iPASP was applied to the formula (i.e. TAPSE/iPASP). The trend was also true for RV-PA coupling using RVFAC (AUCs: 0.561 for RVFAC/ePASP, 0.693 for RVFAC/iPASP). There was a significant correlation between ePASP and iPASP, whereas the correlation was attenuated in patients with TR beyond severe (i.e. massive/torrential TR) (interaction p = 0.01). In addition, a semiquantitative echocardiographic estimation of right atrial (RA) pressure was not correlated with the invasive measurement.

Conclusion

The present analysis confirms that RV-PA coupling, measured as TAPSE/PASP, is a powerful predictor of mortality and rehospitalization due to heart failure in patients undergoing TTVR. The predictability is even more improved if PA pressure is measured invasively and applied to the formulas.

Funding Acknowledgement

Type of funding sources: None.

Validation of expert criteria proposed by the “German Cardiac Society” for predicting procedural complexity in transcatheter edge-to-edge mitral valve repair

Background

Following up on the original EVEREST criteria and several years of procedural experience, the German Cardiac Society (GCS) proposed refined criteria indicating morphological complexity in transcatheter edge-to-edge mitral valve repair (TEER) procedures which so far have not been validated.

Methods

In a retrospective analysis of transesophageal echocardiography images of consecutive patients undergoing TEER in two high-volume centres, complexity was classified according to GCS criteria as optimal (neither characteristics of “complex” nor “very complex', see Table 1), complex (any of the “complex” criteria but no “very complex” criteria) and very complex (any of the “very complex” criteria). Associations with the procedural outcome, reintervention, survival, and heart failure rehospitalization were tested.

Results

633 patients (mean age 79 years, range 50 to 96 years, 59% male) were included, with 35% having dominant primary and 65% having dominant secondary mitral regurgitation (MR). 19% of patients were classified as having optimal, 40% as complex, and 41% as very complex morphologies. Successful clip implantation and reduction in MR ≤2 at discharge were achieved in 100% and 97% in the optimal, in 96% and 88% in the complex, and in 95% and 88% in the very complex morphologies, respectively (p for difference 0.13 and 0.42). The rate of successful clip deployment was significantly lower and the rate of reintervention significantly higher in patients with a mitral valve orifice area ≤3 cm2, compared to patients with a mitral valve orifice area >3 cm2. Pathology extent of MR likely requiring >2 clips was significantly associated with a lower rate of MR reduction to grade ≤2. Midterm (median follow-up time 640 days) mortality or hospitalization due to heart failure was significantly higher in patients with a posterior mitral leaflet length of 7–10 mm.

Conclusion

In the setting of experienced heart valve centres only a few of the complexity criteria proposed by the GCS impact on procedural and clinical outcomes. Even in the case of complex or very complex mitral valve morphology, TEER can be performed effectively with reduction of MR to ≤2 in 88% of cases.

Funding Acknowledgement

Type of funding sources: None.

Effective method of monitoring cerebral tissue oxygen saturation in cardiac surgery patients by combined use of tNIRS-1 and bispectral index

To continuously and noninvasively monitor the cerebral tissue oxygen saturation (StO₂) and hemoglobin concentration (gasHb) in cardiac surgery patients, a method combining the use of a cerebral tissue oximeter using near infrared time-resolved spectroscopy (tNIRS-1) and the bispectral index (BIS) was developed in this study. Moreover, the correlation between the estimated hemoglobin concentration (estHb), measured via tNIRS-1, and the hemoglobin concentration (gasHb), analyzed using a blood gas analyzer, were compared. The relationship between the BIS and gasHb was also examined. Through the comparison of BIS and StO₂ (r1), and estHb and gasHb (r2), the correlation between the two was clarified with maximum r1 and r2 values of 0.617 and 0.946, respectively. The relationship between BIS and gasHb (r3), showed that there was a favorable correlation with a maximum r3 value of 0.969. There was also a continuous correlation between BIS and StO₂ in patients undergoing cardiac surgery. In addition, a strong correlation was found between estHb and gasHb, and between BIS and gasHb. It was therefore concluded that the combined use of BIS and tNIRS-1 is useful to evaluate cerebral hypoxia, allowing for quick response to cerebral hypoxia and reduction of hemoglobin concentration during the operation.

Impact of leaflet-to-annulus index on residual tricuspid regurgitation following transcatheter edge-to-edge tricuspid valve repair

Introduction

Edge-to-edge transcatheter tricuspid valve repair (TTVR) is a promising treatment option for tricuspid regurgitation (TR), and it is required to identify anatomical parameters to predict the procedural success of TTVR.

Purpose

In this study, we assessed leaflet-to-annulus index (LAI), a simple tool to evaluate the remodeling of tricuspid annulus in relation to the leaflets, and investigated the association of the LAI with residual TR after edge-to-edge TTVR.

Methods

Consecutive 140 patients with symptomatic TR who underwent edge-to-edge TTVR from June 2015 to July 2020 were enrolled. The LAI was calculated using preprocedural transesophageal echocardiography and was defined as follows: (anterior leaflet length + septal leaflet length)/anteroseptal tricuspid annulus diameter (Figure 1). Primary outcome was residual TR ≥3+ at discharge, and patients were allocated into two groups as follows: residual TR ≥3+ and <3+. Secondary outcome was the composite outcome, consisting of all-cause mortality and heart failure hospitalization, within one year after TTVR.

Results

Of the 140 patients, 43 patients had residual TR ≥3+ after TTVR. The patients with residual TR ≥3+ had lower LAI compared to those with residual TR <3+ (1.06±0.10 vs. 1.13±0.09; p=0.001). Multivariable analysis revealed that LAI was associated with residual TR ≥3+ (odds ratio [by 0.1 increase]: 0.57; 95% confidence interval [95% CI]: 0.35–0.94; p=0.02), independently of baseline TR severity, location of TR jet, and coaptation gap size (Table 1). Patients with residual TR ≥3+ had a higher incidence of the composite outcome within one year after TTVR (34.9% vs. 18.6%; log-rank p=0.04) and residual TR ≥3+ was an independent predictor of the composite outcome within one year (hazard ratio: 2.04; 95% CI: 1.01–4.11; p=0.04).

Conclusion

Lower LAI is associated with residual TR ≥3+ after edge-to-edge TTVR, which itself was a significant predictor of the one-year composite outcome. Our findings suggest that LAI is a useful tool to identify patients to be successfully treated with edge-to-edge TTVR.

Funding Acknowledgement

Type of funding sources: None. Figure 1Table 1

Risk prediction in patients with classical Low-flow, low-gradient aortic stenosis undergoing TAVI

Background

Patients with classical low-flow, low-gradient aortic stenosis (LFLG AS) undergoing transcatheter aortic valve implantation (TAVI) are known to suffer from poor prognosis. Risk prediction is difficult and predictors of outcome are scarce in this complex patient subset.

Purpose

This study aimed to develop a simple score system for risk prediction in patients with classical LFLG AS scheduled for TAVI including baseline clinical, echocardiographic and computed tomography (CT) parameters.

Methods

Among 9,150 patients undergoing TAVI (2008–2019) at five German centers, patients with classical LFLG AS were screened for availability of sufficient CT data for aortic valve calcification (AVC) quantification. Score variables were defined as all variables included into the best performing multivariable regression model. Score performance was assessed by Kaplan-Meier analysis for the endpoint of 1-year all-cause as well as c-index calculation.

Results

A total of 718 patients were included into the study. Predictors of all-cause mortality were male sex (HR 1.27 [0.98, 1.65], p=0.068), chronic obstructive pulmonary disease (HR 1.59 [1.21,2.08], p<0.001), atrial fibrillation (HR 1.33 [1.03,1.70], p=0.026), stroke volume index (HR 0.96 [0.94, 0.98], p<0.001), non-transfemoral access (HR 1.44 [1.09,1.91], p=0.011), pulmonary hypertension (HR 1.58 [1.20,2.08], p=0.0012) and low AVC density (HR 1.49 [1.16,1.90], p=0.0016). A score system was developed ranging from 0 points to 11 points. Kaplan-Meier analysis for low (0–2 points), moderate (3–6 points) and high score (>6 points) demonstrated 1-year mortality rates of 20.9%, 28.9% and 64.3% (p<0.001), respectively. C-index for prediction of 1-year mortality was 0.69 (95%-CI 0.65–0.84). The RELiEF TAVI score outperformed classical risk prediction models like the logistic euroSCORE (c-index 0.60 [95%-CI 0.51–0.72], p=0.013), the EuroSCORE II (c-index 0.57 [95%-CI 0.45–0.70], p=0.039) and the STS PROM (c-index 0.60 [0.48–0.70], p=0.035).

Conclusions

The RELiEF TAVI score is based on simple clinical, echocardiographic and CT parameters and might serve as a helpful tool for risk prediction in the vulnerable subset of patients with classical LFLG AS scheduled for TAVI.

Funding Acknowledgement

Type of funding sources: None. RELiEF TAVI Score

Long-term prognosis and genetic background of cardiomyopathy in 223 pediatric mitochondrial disease patients

BACKGROUND

Cardiomyopathy is a risk factor for poor prognosis in pediatric patients with mitochondrial disease. However, other risk factors including genetic factors related to poor prognosis in mitochondrial disease has yet to be fully elucidated.

METHODS AND RESULTS

Between January 2004 and September 2019, we enrolled 223 consecutive pediatric mitochondrial disease patients aged <18 years with a confirmed genetic diagnosis, including 114 with nuclear gene mutations, 89 patients with mitochondrial DNA (mtDNA) point mutations, 11 with mtDNA single large-scale deletions and 9 with chromosomal aberrations. Cardiomyopathy at baseline was observed in 46 patients (22%). Hazard ratios (HR) and 95% confidence intervals (CI) were calculated for all-cause mortality. Over a median follow-up of 36 months (12-77), there were 85 deaths (38%). The overall survival rate was significantly lower in patients with cardiomyopathy than in those without (p < 0.001, log-rank test). By multivariable analysis, left ventricular (LV) hypertrophy (HR = 4.6; 95% CI: 2.8-7.3), neonatal onset (HR = 2.9; 95% CI: 1.8-4.5) and chromosomal aberrations (HR = 2.9; 95% CI: 1.3-6.5) were independent predictors of all-cause mortality. Patients with LV hypertrophy with neonatal onset and/or chromosomal aberrations had higher mortality (100% in 21 patients) than those with LV hypertrophy alone (71% in 14 patients).

CONCLUSION

In pediatric patients with mitochondrial disease, cardiomyopathy was common (22%) and was associated with increased mortality. LV hypertrophy, neonatal onset and chromosomal aberrations were independent predictors of all-cause mortality. Prognosis is particularly unfavourable if LV hypertrophy is combined with neonatal onset and/or chromosomal aberrations.

Identification of Sox2 and NeuN Double-Positive Cells in the Mouse Hypothalamic Arcuate Nucleus and Their Reduction in Number With Aging

The hypothalamus plays a central role in homeostasis and aging. The hypothalamic arcuate nucleus (ARC) controls homeostasis of food intake and energy expenditure and retains adult neural stem cells (NSCs)/progenitor cells. Aging induces the loss of NSCs and the enhancement of inflammation, including the activation of glial cells in the ARC, but aging-associated alterations of the hypothalamic cells remain obscure. Here, we identified Sox2 and NeuN double-positive cells in a subpopulation of cells in the mouse ARC. These cells were reduced in number with aging, although NeuN-positive neuronal cells were unaltered in the total number. Diet-induced obesity mice fed with high-fat diet presented a similar hypothalamic alteration to aged mice. This study provides a new insight into aging-induced changes in the hypothalamus.

Afadin regulates actomyosin organization through αE-catenin at adherens junctions

Actomyosin-undercoated adherens junctions are critical for epithelial cell integrity and remodeling. Actomyosin associates with adherens junctions through αE-catenin complexed with β-catenin and E-cadherin in vivo; however, in vitro biochemical studies in solution showed that αE-catenin complexed with β-catenin binds to F-actin less efficiently than αE-catenin that is not complexed with β-catenin. Although a "catch-bond model" partly explains this inconsistency, the mechanism for this inconsistency between the in vivo and in vitro results remains elusive. We herein demonstrate that afadin binds to αE-catenin complexed with β-catenin and enhances its F-actin-binding activity in a novel mechanism, eventually inducing the proper actomyosin organization through αE-catenin complexed with β-catenin and E-cadherin at adherens junctions.

One-year outcome of transcatheter repair of tricuspid regurgitation: comparison edge-to-edge repair versus anuloplasty

 

Tricuspid regurgitation (TR) is found to be associated with increased mortality, morbidity, and impaired quality of life. The interventional tricuspid valve repair techniques are being increasingly performed. We aimed to compare the mid-term outcomes of both methods (Clipping and Banding) in our patient cohort. F

We retrospectively included 60 patients who underwent between January 2016 to March 2018 the transcatheter tricuspid valve edge-to-edge repair or annuloplasty in our center. Follow up (FU) examinations were done 12.6±7.6 months. Comprehensive transthoracic echocardiography inclusively 3D acquisitions were performed before and at FU in all patients. The 3D data were used for strain analysis of left and right ventricles and atriums through a dedicated automated offline program (TomTec).

We retrospectively included 60 patients (75±6.1 years, 40% female) with symptomatic (65% ascites, 95% edema, 100% NYHA&gt;II, 75% liver congestion) severe TR (TR&gt;II, 90% functional) at surgical high risk (EuroSCORE II: 5.2±3.2%). Forty patients underwent transcatheter TV edge-to-edge repair (TTVR, MitraClip, PASCAL), and twenty patients were treated by interventional annuloplasty (Cardioband).

At baseline, the patients underwent edge-to-edge (E2E) repair showed more comorbidities with higher EuroScore II and more decreased functional capacity. Echocardiographical, patients who underwent annuloplasty, presented a more significant coaptation gap with more impaired RV function and more dilated right atrium. In contrast, the E2E group showed to have higher right ventricular systolic pressure. Left ventricular dimensions and functions were comparable between the groups.

Left atrial volume and right atrial pressure were found to be statistically significantly reduced in both groups at FU. RV and RA fractional area change were found to be relevantly improved solely after interventional annuloplasty at FU. Left ventricular end-diastolic pressure significantly increased in the E2E group with relevant reduction of outflow/inflow ratio. Moreover, interventional annuloplasty, as expected, reduces SL diameter more significantly.

Patients showed lower symptoms and better functional capacity 12 months after interventional E2E therapy. Of note, improvement in walking distance was found to be significantly higher in patients who underwent annuloplasty. However, patients were hospitalized significantly more frequently after interventional annuloplasty.

In conclusion, both interventional techniques are safe, feasible, and effective for treatment of tricuspid regurgitation in patients at surgical high risk. Interventional annuloplasty significantly impacts on RV function and geometry, and reduces SL diameter significantly. Patients were found to have decreased symptoms, better functional capacity, as well as fewer rehospitalization 12 months after interventional E2E therapy, although they showed more comorbidities at baseline compared to interventional annuloplasty.

Funding Acknowledgement

Type of funding source: None

Risk factors and etiology of recurrent mitral regurgitation after edge-to-edge mitral valve repair

Background

Recurrent MR has been associated with poor prognosis after transcatheter mitral valve repair (TMVR) with the MitraClip system. However, little is known about risk factors and etiology of recurrent mitral regurgitation (MR) after transcatheter edge-to-edge mitral repair with the MitraClip system.

Methods

Among consecutive patients who underwent MitraClip for MR from January 2011 to March 2019, we identified 240 patients who had MR ≤2+ at discharge and follow-up echocardiography within three years after the procedure. Recurrent MR was defined as MR ≥3+ during the follow-up period. To investigate the risk factors for recurrent MR, we conducted a Cox proportional hazard model.

Results

During the follow-up period (median 491 days), 38 patients (15.8%) had recurrent MR (≥3+). The most frequent etiology of recurrent MR was degenerative (n=20, 52.6%), including single leaflet detachment (n=2, 5.3%), loss of leaflet insertion (n=11, 28.9%), and leaflet tear or prolapse (n=7, 18.4%), followed by functional MR (n=18, 47.4%). The risk factors for recurrent MR were greater LV end-diastolic volume (adjusted-HR 1.01, 95% CI 1.00–1.02, p=0.03), higher LV ejection fraction (LVEF) (adjusted-HR 1.05, 95% CI 1.01–1.08, p=0.005), and moderate MR upon discharge (adjusted-HR 2.98, 95% CI 1.50–5.95, p=0.002).After stratification according to the etiology of MR, the association of LVEF was more pronounced in patients with degenerative MR (adjusted-HR 1.07, 95% CI 1.02–1.12, p=0.003), while the association of moderate MR upon discharge was more pronounced in patients with functional MR (adjusted-HR 5.02, 95% CI 1.95–12.8, p&lt;0.001). Furthermore, patients with recurrent MR had an increased antero-posterior annulus diameter regardless of the baseline etiology of the MR.

Conclusions

Greater LV volume, higher LVEF, and moderate MR at discharge were associated with an increased risk of recurrent MR after the MitraClip procedure. A significant increase of the annulus diameter was observed regardless of the baseline etiology of the MR.

Etiology of recurrent MR

Funding Acknowledgement

Type of funding source: None

Acute response of right ventricular function following transcatheter mitral valve repair

Background

Little is known about early right ventricular (RV) response to transcatheter mitral valve repair (TMVR) and its association with clinical outcomes. We assessed the early effect of TMVR on the RV function (RVF) and sought to investigated the prognostic impact of post-procedural RV dysfunction.

Methods

From January 2011 through April 2019, consecutive patients who underwent MitraClip for severe mitral regurgitation were analyzed. We excluded patients in which the evaluation of RVF were un available. RV dysfunction was defined by an RV fractional area change (RVFAC) &lt;35% or tricuspid annular planar systolic excursion (TAPSE) &lt;16 mm. A Cox proportional regression analysis was conducted to investigate the association of post-procedural RV dysfunction with adverse outcomes (all-cause mortality and rehospitalization due to heart failure [HF]).

Results

A total of 403 patients were analyzed.Overall, the mean age was 78 years old and 59% of patients were male. The median left-ventricular ejection fraction (LVEF) was 46.1% [IQR 33.1–59.4], RVFAC was 41.9% [IQR 32.9–49.5], and TAPSE was 17 mm [IQR 14–22]. While 68 patients showed an acute improvement of RVF (35% of patients with baseline RV dysfunction), 51 patients (25% of patients with baseline normal RVF) showed an acute worsening of RVF. In patients with baseline normal RVF, atrial fibrillation (OR 4.57, 95% CI 1.56–13.40, p=0.006, HF duration &gt;18 months (OR 2.95, 95% CI 1.32–6.60, p=0.009), LVEF &lt;50% (OR 3.09, 95% CI 1.32–7.25, p=0.009), and tricuspid regurgitation≥3+ (OR 5.62, 2.28–13.90, p&lt;0.001)were associated with an increased risk of acute worsening of RVF. By contrast, in patients with baseline RV dysfunction, HF duration &gt;18 months (OR 0.43, 95% CI 0.22–0.85, p=0.01) and larger RV volume (OR 0.98, 95% CI 0.97–0.99, p&lt;0.001) were associated with less probability of acute RVF improvement. The event-free survival was significantly different according to the subgroup of variation of RVF (p=0.003). Furthermore, post-procedural RV dysfunction was associated with an increased risk of outcomes (adjusted-HR 2.38, 95% CI 1.28–4.43, p=0.006).

Conclusion

Both acute improvement and worsening of RVF can be observed after TMVR. Post-procedural RV dysfunction is an independent predictor of adverse outcomes.

Event-free survival curve

Funding Acknowledgement

Type of funding source: None

MitoBlue as a tool to analyze the mitochondria-lysosome communication

MitoBlue is a fluorescent bisamidine that can be used to easily monitor the changes in mitochondrial degradation processes in different cells and cellular conditions. MitoBlue staining pattern is exceptional among mitochondrial dyes and recombinant fluorescent probes, allowing the dynamic study of mitochondrial recycling in a variety of situations in living cells. MitoBlue is a unique tool for the study of these processes that will allow the detailed characterization of communication between mitochondria and lysosomes.

Critical Role of Lipid Scramblase TMEM16F in Phosphatidylserine Exposure and Repair of Plasma Membrane after Pore Formation

Plasma membrane damage and cell death during processes such as necroptosis and apoptosis result from cues originating intracellularly. However, death caused by pore-forming agents, like bacterial toxins or complement, is due to direct external injury to the plasma membrane. To prevent death, the plasma membrane has an intrinsic repair ability. Here, we found that repair triggered by pore-forming agents involved TMEM16F, a calcium-activated lipid scramblase also mutated in Scott's syndrome. Upon pore formation and the subsequent influx of intracellular calcium, TMEM16F induced rapid "lipid scrambling" in the plasma membrane. This response was accompanied by membrane blebbing, extracellular vesicle release, preserved membrane integrity, and increased cell viability. TMEM16F-deficient mice exhibited compromised control of infection by Listeria monocytogenes associated with a greater sensitivity of neutrophils to the pore-forming Listeria toxin listeriolysin O (LLO). Thus, the lipid scramblase TMEM16F is critical for plasma membrane repair after injury by pore-forming agents.

Nectin-4 cis-interacts with ErbB2 and its trastuzumab-resistant splice variants, enhancing their activation and DNA synthesis

Nectin-4 cell adhesion molecule and ErbB2 tyrosine kinase receptor are upregulated in many cancers, including breast cancer, and promote cancer cell proliferation and metastasis. Using human breast cancer cell lines T47D and SUM190-PT, in which both nectin-4 and ErbB2 were upregulated, we showed here that nectin-4 cis-interacted with ErB2 and enhanced its dimerization and activation, followed by the activation of the phosphoinositide 3-kinase-AKT signalling pathway for DNA synthesis. The third immunoglobulin-like domain of nectin-4 cis-interacted with domain IV of ErbB2. This region differs from the trastuzumab-interacting region but is included in the trastuzumab-resistant splice variants of ErbB2, p95-ErbB2 and ErbB2ΔEx16. Nectin-4 also cis-interacted with these trastuzumab-resistant splice variants and enhanced the activation of the phosphoinositide 3-kinase-AKT signalling pathway for DNA synthesis. In addition, nectin-4 enhanced the activation of the p95-ErbB2-induced JAK-STAT3 signalling pathway, but not the ErbB2- or ErbB2ΔEx16-induced JAK-STAT3 signalling pathway. These results indicate that nectin-4 cis-interacts with ErbB2 and its trastuzumab-resistant splice variants and enhances the activation of these receptors and downstream signalling pathways in a novel mechanism.

P4715Association of heart failure duration with clinical prognosis after transcatheter mitral valve repair

Background/Introduction

Transcatheter mitral valve repair (TMVR) in patients with heart failure (HF) and severe mitral regurgitation (MR) entails better clinical and symptomatic status. While emerging evidence indicate that HF duration is linked to adverse outcomes in patients with HF, it is not known whether the HF duration before TMVR has an effect on adverse outcomes.

Purpose

We aimed to assess the association between duration of HF before TMVR and clinical prognosis after the procedure.

Methods

We retrospectively enrolled a total of 345 patients who underwent TMVR procedure with MitraClip or Cardioband system for the treatment of symptomatic MR after guideline recommended therapy. The patients were divided into 2 groups according to the duration of HF (>18 months:, n=161, ≤18 months: shorter HF group, n=184). Cox proportional hazards analysis was performed to assess the association between duration and two-year composite endpoint (all-cause mortality, unexpected hospitalization due to HF, and repeat mitral valve therapy).

Results

Patients with longer duration of HF were more likely to be male, had greater incidence of coronary artery disease (77.0% vs. 51.6%, p<0.001), had received more frequently implantable cardioverter defibrillator or cardiac resynchronization therapy (41.0% vs. 10.3%, p<0.001), and had more decreased left ventricular ejection fraction (41.1±14.5% vs. 49.3±16.0%, p<0.001) compared to patients with shorter duration of HF. Two-year event-free survival rate was significantly lower in patients with longer duration of HF (66.3% vs. 83.8%, Log-rank p=0.01) compared to whose with shorter duration of HF. Similar trends were observed for all-cause mortality (84.8% vs. 95.9%, p=0.06) and repeat mitral valve therapy (93.4% vs. 100%, p=0.02). In the Cox proportional hazard analysis, longer duration of HF was independently associated with increased risk of adverse outcomes (Hazard ratio, 2.26; 95% confidence interval, 1.11–4.62; p=0.02) compared with shorter duration of HF.

Conclusion

Patients with the longer duration of HF before TMVR is independently associated with increased risk of adverse outcomes after the procedure. It is, however, accompanied by higher prevalence of cardiac co-morbidities in these patients. Our findings suggest that a longer duration of HF is a risk indicator and should be considered into in future clinical trials of TMVR.

MITOL deletion in the brain impairs mitochondrial structure and ER tethering leading to oxidative stress

MITOL deletion in mouse brain impairs the morphology and ER tethering of mitochondria, resulting in enhanced oxidative stress. This study suggests a relationship between morphological abnormalities of mitochondria and developmental disorder.

Mitochondrial abnormalities are associated with developmental disorders, although a causal relationship remains largely unknown. Here, we report that increased oxidative stress in neurons by deletion of mitochondrial ubiquitin ligase MITOL causes a potential neuroinflammation including aberrant astrogliosis and microglial activation, indicating that mitochondrial abnormalities might confer a risk for inflammatory diseases in brain such as psychiatric disorders. A role of MITOL in both mitochondrial dynamics and ER-mitochondria tethering prompted us to characterize three-dimensional structures of mitochondria in vivo. In MITOL-deficient neurons, we observed a significant reduction in the ER-mitochondria contact sites, which might lead to perturbation of phospholipids transfer, consequently reduce cardiolipin biogenesis. We also found that branched large mitochondria disappeared by deletion of MITOL. These morphological abnormalities of mitochondria resulted in enhanced oxidative stress in brain, which led to astrogliosis and microglial activation partly causing abnormal behavior. In conclusion, the reduced ER-mitochondria tethering and excessive mitochondrial fission may trigger neuroinflammation through oxidative stress.

Membrane dynamics and organelle biogenesis-lipid pipelines and vesicular carriers

Discoveries spanning several decades have pointed to vital membrane lipid trafficking pathways involving both vesicular and non-vesicular carriers. But the relative contributions for distinct membrane delivery pathways in cell growth and organelle biogenesis continue to be a puzzle. This is because lipids flow from many sources and across many paths via transport vesicles, non-vesicular transfer proteins, and dynamic interactions between organelles at membrane contact sites. This forum presents our latest understanding, appreciation, and queries regarding the lipid transport mechanisms necessary to drive membrane expansion during organelle biogenesis and cell growth.

Formation of mitochondrial-derived vesicles is an active and physiologically relevant mitochondrial quality control process in the cardiac system

KEY POINTS

Mitochondrial-derived vesicle (MDV) formation occurs under baseline conditions and is rapidly upregulated in response to stress-inducing conditions in H9c2 cardiac myoblasts. In mice formation of MDVs occurs readily in the heart under normal healthy conditions while mitophagy is comparatively less prevalent. In response to acute stress induced by doxorubicin, mitochondrial dysfunction develops in the heart, triggering MDV formation and mitophagy. MDV formation is thus active in the cardiac system, where it probably constitutes a baseline housekeeping mechanism and a first line of defence against stress.

ABSTRACT

The formation of mitochondrial-derived vesicles (MDVs), a process inherited from bacteria, has emerged as a potentially important mitochondrial quality control (QC) mechanism to selectively deliver damaged material to lysosomes for degradation. However, the existence of this mechanism in various cell types, and its physiological relevance, remains unknown. Our aim was to investigate the dynamics of MDV formation in the cardiac system in vitro and in vivo. Immunofluorescence in cell culture, quantitative transmission electron microscopy and electron tomography in vivo were used to study MDV production in the cardiac system. We show that in cardiac cells MDV production occurs at baseline, is commensurate with the dependence of cells on oxidative metabolism, is more frequent than mitophagy and is up-regulated on the time scale of minutes to hours in response to prototypical mitochondrial stressors (antimycin-A, xanthine/xanthine oxidase). We further show that MDV production is up-regulated together with mitophagy in response to doxorubicin-induced mitochondrial and cardiac dysfunction. Here we provide the first quantitative data demonstrating that MDV formation is a mitochondrial QC operating in the heart.

Parkinson's Disease-Related Proteins PINK1 and Parkin Repress Mitochondrial Antigen Presentation

Antigen presentation is essential for establishing immune tolerance and for immune responses against infectious disease and cancer. Although antigen presentation can be mediated by autophagy, here we demonstrate a pathway for mitochondrial antigen presentation (MitAP) that relies on the generation and trafficking of mitochondrial-derived vesicles (MDVs) rather than on autophagy/mitophagy. We find that PINK1 and Parkin, two mitochondrial proteins linked to Parkinson's disease (PD), actively inhibit MDV formation and MitAP. In absence of PINK1 or Parkin, inflammatory conditions trigger MitAP in immune cells, both in vitro and in vivo. MitAP and the formation of MDVs require Rab9 and Sorting nexin 9, whose recruitment to mitochondria is inhibited by Parkin. The identification of PINK1 and Parkin as suppressors of an immune-response-eliciting pathway provoked by inflammation suggests new insights into PD pathology.

MAPL SUMOylation of Drp1 Stabilizes an ER/Mitochondrial Platform Required for Cell Death

There has been evidence that mitochondrial fragmentation is required for apoptosis, but the molecular links between the machinery regulating dynamics and cell death have been controversial. Indeed, activated BAX and BAK can form functional channels in liposomes, bringing into question the contribution of mitochondrial dynamics in apoptosis. We now demonstrate that the activation of apoptosis triggers MAPL/MUL1-dependent SUMOylation of the fission GTPase Drp1, a process requisite for cytochrome c release. SUMOylated Drp1 functionally stabilizes ER/mitochondrial contact sites that act as hotspots for mitochondrial constriction, calcium flux, cristae remodeling, and cytochrome c release. The loss of MAPL does not alter the activation and assembly of BAX/BAK oligomers, indicating that MAPL is activated downstream of BAX/BAK. This work demonstrates how interorganellar contacts are dynamically regulated through active SUMOylation during apoptosis, creating a stabilized platform that signals cytochrome c release.

A new pathway for mitochondrial quality control: mitochondrial-derived vesicles

The last decade has been marked by tremendous progress in our understanding of the cell biology of mitochondria, with the identification of molecules and mechanisms that regulate their fusion, fission, motility, and the architectural transitions within the inner membrane. More importantly, the manipulation of these machineries in tissues has provided links between mitochondrial dynamics and physiology. Indeed, just as the proteins required for fusion and fission were identified, they were quickly linked to both rare and common human diseases. This highlighted the critical importance of this emerging field to medicine, with new hopes of finding drugable targets for numerous pathologies, from neurodegenerative diseases to inflammation and cancer. In the midst of these exciting new discoveries, an unexpected new aspect of mitochondrial cell biology has been uncovered; the generation of small vesicular carriers that transport mitochondrial proteins and lipids to other intracellular organelles. These mitochondrial-derived vesicles (MDVs) were first found to transport a mitochondrial outer membrane protein MAPL to a subpopulation of peroxisomes. However, other MDVs did not target peroxisomes and instead fused with the late endosome, or multivesicular body. The Parkinson's disease-associated proteins Vps35, Parkin, and PINK1 are involved in the biogenesis of a subset of these MDVs, linking this novel trafficking pathway to human disease. In this review, we outline what has been learned about the mechanisms and functional importance of MDV transport and speculate on the greater impact of these pathways in cellular physiology.

Status of a compact electron cyclotron resonance ion source for National Institute of Radiological Sciences-930 cyclotron

The Kei-source is a compact electron cyclotron resonance ion source using only permanent magnets and a frequency of 10 GHz. It was developed at the National Institute of Radiological Sciences (NIRS) for producing C(4+) ions oriented for high-energy carbon therapy. It has also been used as an ion source for the NIRS-930 cyclotron. Its microwave band region for the traveling-wave-tube amplifier and maximum output power are 8-10 GHz and 350 W, respectively. Since 2006, it has provided various ion beams such as proton, deuteron, carbon, oxygen, and neon with sufficient intensity (200 μA for proton and deuteron, 50 μA for C(4+), for example) and good stability for radioisotope production, tests of radiation damage, and basic research experiments. Its horizontal and vertical emittances were measured using a screen monitor and waist-scan. The present paper reports the current status of the Kei-source.

Status of ion sources at National Institute of Radiological Sciences

The National Institute of Radiological Sciences (NIRS) maintains various ion accelerators in order to study the effects of radiation of the human body and medical uses of radiation. Two electrostatic tandem accelerators and three cyclotrons delivered by commercial companies have offered various life science tools; these include proton-induced x-ray emission analysis (PIXE), micro beam irradiation, neutron exposure, and radioisotope tracers and probes. A duoplasmatron, a multicusp ion source, a penning ion source (PIG), and an electron cyclotron resonance ion source (ECRIS) are in operation for these purposes. The Heavy-Ion Medical Accelerator in Chiba (HIMAC) is an accelerator complex for heavy-ion radiotherapy, fully developed by NIRS. HIMAC is utilized not only for daily treatment with the carbon beam but also for fundamental experiments. Several ECRISs and a PIG at HIMAC satisfy various research and clinical requirements.

CRMP5-associated GTPase (CRAG) protein protects neuronal cells against cytotoxicity of expanded polyglutamine protein partially via c-Fos-dependent activator protein-1 activation

We previously demonstrated that CRAM (CRMP5)-associated GTPase (CRAG), a short splicing variant of centaurin-γ3/AGAP3, facilitated degradation of expanded polyglutamine protein (polyQ) via the nuclear ubiquitin-proteasome pathway. Taking advantage of this feature, we also showed that lentivirus-mediated CRAG expression in the Purkinje cells of mice expressing polyQ resulted in clearance of the polyQ aggregates and rescue from ataxia. However, the molecular basis of the function of CRAG in cell survival against polyQ remains unclear. Here we report that CRAG, but not centaurin-γ3, induces transcriptional activation of c-Fos-dependent activator protein-1 (AP-1) via serum response factor (SRF). Mutation analysis indicated that the nuclear localization signal and both the N- and C-terminal regions of CRAG are critical for SRF-dependent c-Fos activation. CRAG knockdown by siRNA or expression of a dominant negative mutant of CRAG significantly attenuated the c-Fos activation triggered by either polyQ or the proteasome inhibitor MG132. Importantly, c-Fos expression partially rescued the enhanced cytotoxicity of CRAG knockdown in polyQ-expressing or MG132-treated cells. Finally, we suggest the possible involvement of CRAG in the sulfiredoxin-mediated antioxidant pathway via AP-1. Taken together, these results demonstrated that CRAG enhances the cell survival signal against the accumulation of unfolded proteins, including polyQ, through not only proteasome activation, but also the activation of c-Fos-dependent AP-1.

A mitochondrial ubiquitin ligase MITOL controls cell toxicity of polyglutamine-expanded protein

Expansion of a polyglutamine tract in ataxin-3 (polyQ) causes Machado-Joseph disease, a late-onset neurodegenerative disorder characterized by ubiquitin-positive aggregate formation. Several lines of evidence demonstrate that polyQ also accumulates in mitochondria and causes mitochondrial dysfunction. To uncover the mechanism of mitochondrial quality-control via the ubiquitin-proteasome pathway, we investigated whether MITOL, a novel mitochondrial ubiquitin ligase localized in the mitochondrial outer membrane, is involved in the degradation of pathogenic ataxin-3 in mitochondria. In this study, we used N-terminal-truncated pathogenic ataxin-3 with a 71-glutamine repeat (ΔNAT-3Q71) and found that MITOL promoted ΔNAT-3Q71 degradation via the ubiquitin-proteasome pathway and attenuated mitochondrial accumulation of ΔNAT-3Q71. Conversely, MITOL knockdown induced an accumulation of detergent-insoluble ΔNAT-3Q71 with large aggregate formation, resulting in cytochrome c release and subsequent cell death. Thus, MITOL plays a protective role against polyQ toxicity, and thereby may be a potential target for therapy in polyQ diseases. Our findings indicate a protein quality-control mechanism at the mitochondrial outer membrane via a MITOL-mediated ubiquitin-proteasome pathway.

Mitochondrial ubiquitin ligase MITOL ubiquitinates mutant SOD1 and attenuates mutant SOD1-induced reactive oxygen species generation

We have previously identified a novel mitochondrial ubiquitin ligase, MITOL, which is localized in the mitochondrial outer membrane and is involved in the control of mitochondrial dynamics. In this study, we examined whether MITOL eliminates misfolded proteins localized to mitochondria. Mutant superoxide dismutase1 (mSOD1), one of misfolded proteins, has been shown to localize in mitochondria and induce mitochondrial dysfunction, possibly involving in the onset and progression of amyotrophic lateral sclerosis. We found that in the mitochondria, MITOL interacted with and ubiquitinated mSOD1 but not wild-type SOD1. In vitro ubiquitination assay revealed that MITOL directly ubiquitinates mSOD1. Cycloheximide-chase assay in the Neuro2a cells indicated that MITOL overexpression promoted mSOD1 degradation and suppressed both the mitochondrial accumulation of mSOD1 and mSOD1-induced reactive oxygen species (ROS) generation. Conversely, the overexpression of MITOL CS mutant and MITOL knockdown by specific siRNAs resulted in increased accumulation of mSOD1 in mitochondria, which enhanced mSOD1-induced ROS generation and cell death. Thus, our findings indicate that MITOL plays a protective role against mitochondrial dysfunction caused by the mitochondrial accumulation of mSOD1 via the ubiquitin-proteasome pathway.

Development of gas pulsing system for electron cyclotron resonance ion source

A gas-pulsing system for an electron cyclotron resonance ion source with all permanent magnets (Kei2 source) at NIRS has been developed and tested. The system consists of a small vessel (30 ml) to reserve CH(4) gas and two fast solenoid valves that are installed at both sides of the vessel. They are connected to each other and to the Kei2 source by using a stainless-steel pipe (4 mm inner diameter), where the length of the pipe from the valve to the source is 60 cm and the conductance is 1.2 l/s. From the results of the test, almost 300 e microA for a pulsed (12)C(4+) beam was obtained at a Faraday cup in an extraction-beam channel with a pressure range of 4000 Pa in the vessel. At this time, the valve has an open time of 10 ms and the delay time between the valve open time and the application of microwave power is 100 ms. In experiments, the conversion efficiency for input CH(4) molecules to the quantity of extracted (12)C(4+) ions in one beam pulse was found to be around 3% and the ratio of the total amount of the gas requirement was only 10% compared with the case of continuous gas provided in 3.3 s of repetition in HIMAC.

Water Renew systems: wastewater polishing using renewable energy crops

Macronutrients concentrations were measured during the establishment year of short rotation coppice of Salix viminalis, Populus trichocarpa, Eucalyptus gunnii irrigated with secondary treated effluent. Twenty four plots of 12.25 m2 located in Cranfield, Bedfordshire, UK on heavy fine clay were drip-irrigated in order to maintain their soil moisture at field capacity. Soil water was sampled at 30 cm and 60 cm with soil water suction cup samplers fortnightly. Willow and eucalyptus received more than 900 mm of effluent corresponding to more than 290 kg-N/ha, 30 kg-P/ha and 220 kg-K/ha. Poplar and unplanted plots received less than 190 kg-N/ha, 17 kg-P/ha and 120 kg-K/ha. For soil water nitrogen concentrations as for potassium concentrations, there was an irrigation effect only on eucalyptus planted plots. On all plots, there was no significant effect of tree presence or species. There was no phosphorus measurable in soil water samples. Groundwater chemistry was unaffected by irrigation. Thus, intensive irrigation of short rotation coppice during the establishment year should not be considered as a major threat to groundwater quality. Willows and eucalyptus can absorb almost a third more effluent than poplar and unplanted plots without having any significant effect on soil water chemistry.

An in vitro interethnic comparison of monoamine oxidase activities between Japanese and Caucasian livers using rizatriptan, a serotonin receptor 1B/1D agonist, as a model drug

AIMS

Monoamine oxidase (MAO) is located in human liver, and catalyses the oxidative deamination step of many xenobiotics. However, whether there exists an interethnic difference in MAO activities has, to our knowledge, not been clarified. We aimed to assess the MAO type A (MAO-A) involvement in the metabolic pathway of rizatriptan (RIZ), an antimigraine 5-hydroxytryptamine (5-HT)1B/1D agonist, and the interethnic difference in MAO activities between Caucasians and Japanese using RIZ as a model drug in in vitro experiments.

METHODS

Oxidative deaminase activities were determined with the subcellular fractions of Japanese livers and the microsomal fraction of Caucasian livers using RIZ, 5-HT (MAO-A substrate) and 2-phenylethylamine (PEA) (MAO-B substrate) as substrates.

RESULTS

The oxidative deaminase activities of RIZ vs. 5-HT were highly (r = 0.87 and 0.96, P < 0.001) correlated with each other in both the microsomal and mitochondrial fractions of Japanese livers. Subsequent results were obtained from in vitro experiments using liver microsomes based upon these findings. The oxidative deaminase activities of RIZ were inhibited completely by the nanomolar-order concentration of clorgyline and Ro 41-1049 (MAO-A selective inhibitors), but not by that of Ro 16-6491 (MAO-B selective inhibitor). The majority of the mean Michaelis-Menten values for three substrates toward MAO obtained from six Japanese and six Caucasian liver microsomes reached no significant differences between the two ethnic groups. The mean microsomal oxidative deaminase activities assessed in 18 Japanese and 20 Caucasian livers using the three substrates also showed no significant differences between the two ethnic groups.

CONCLUSIONS

RIZ is mainly metabolized by MAO-A and the in vitro oxidative deaminase activities mediated via MAO-A and -B do not appear to differ between Japanese and Caucasians.

Identification of a non-S RNase, a possible ancestral form of S-RNases, in Prunus

This study identifies and characterizes a basic non-S RNase in the styles with stigmas of sweet cherry (Prunus avium L.), a member of the Rosaceae subfamily Amygdaloideae, which has an RNase-based gametophytic self-incompatibility system. Internal sequences of putative non-S RNases (RNase PA1 and PA2) were determined, and a cDNA for PA1 was obtained. The deduced amino acid sequence of PA1 contained two conserved sequence motifs essential for T2/ S-type RNase activity. PA1 shows 20-30% sequence identity to S-RNases of Rosaceae, Solanaceae and Scrophulariaceae, and non-S RNases of higher plants. Transcription of the PA1 gene was specific to the styles with stigmas, and the gene was not expressed in other tissues. Although PA1 resembles RNase X2, a non-S RNase from Petunia inflata, the placement of PA1 and RNase X2 in the phylogenetic tree was quite different. Placement of PA1 was also distinct from that of rosaceous S-RNases, while RNase X2 was incorporated in the clade of S-RNases from the Solanaceae. The sole intron in the PA1 gene is located at a position equivalent to that of the second intron of amygdaloid S-RNase genes, and that of the only intron in most other S-RNase genes. Genomic Southern analysis revealed the presence of sequences homologous to PA1 in all of the other four Prunus species tested, suggesting that PA1 has an important physiological function. The significance of the discovery of PA1 is discussed in terms of the origin and evolution of S-RNases and self-incompatibility in Rosaceae.

Transient ventricular wall thickening in acute myocarditis: a serial echocardiographic and histopathologic study

The present study was designed to determine whether the wall thickening seen in acute myocarditis is caused by interstitial edema. The study group comprised 25 patients (idiopathic myocarditis, 17; eosinophilic myocarditis, 8) in whom acute myocarditis was diagnosed histologically and who underwent echocardiography and endomyocardial biopsy during both the acute and convalescent phases. The following echocardiographic parameters were measured: interventricular septum and left ventricular posterior wall thickness, left ventricular end-diastolic dimension, and left ventricular ejection fraction. Based on the myocardial biopsy specimens, the degree of interstitial edema was classified into 3 grades [(-), 1(+), 2(+)] and the transverse diameter of cardiac myocytes was measured using light microscopy. The thickness of both the interventricular septum and left ventricular wall decreased from 14.3+/-3.7 mm and 13.3+/-2.4 mm in the acute phase to 9.7+/-1.7 mm (p<0.001) and 10.2+/-1.7 mm (p<0.0001), respectively, in the convalescent phase. Edema was present in 22 patients (88.0%) in the acute phase, but in the convalescent phase, edema was present in only 7 patients (28.0%), indicating a significant reduction in the degree of edema (p<0.0001). Cardiac myocyte diameter did not differ significantly between the acute (13.6+/-1.1 microm) and convalescent (13.8+/-1.8 microm) phases.

Inheritance of S(f)-RNase in Japanese apricot ( Prunus mume) and its relation to self-compatibility

Self-compatible cultivars of Japanese apricot ( Prunus mume Shieb. et Zucc.), a tree species that normally shows S-RNase-based self-incompatiblity, have a horticultural advantage over self-incompatible cultivars. Inheritance of self-compatibility and a common S(f)-RNase allele that is observed in self-compatible cultivars was investigated using progenies from controlled crosses. Total DNAs were isolated from the parents and progenies of seven crosses that included at least one self-compatible cultivar as a parent. These DNAs were PCR-amplified with the Pru-C2 and PCE-R primer pair to determine S-haplotypes of the parents and progenies. A novel S-haplotype, S(8), was found. In all crosses examined, the S(f)-RNase gene was inherited from either the seed or pollen parent as a pistil S-allele in a non-functional S-haplotype. Self-compatibility of about 20 trees each from reciprocal crosses of 'Benisashi ( S(7) S(f))' and 'Shinpeidayu ( S(3) S(f))', and 26 selections from 16 different crosses was tested by pollination and pollen-tube growth studies. Cosegregation of the S(f)-RNase allele and self-compatibility was confirmed with all but selection 1K0-26 ( S(3) S(7)). Selection 1K0-26 ( S(3) S(7)) that originated from 'Benisashi ( S(7) S(f))' x 'Koshinoume ( S(3) S(f))' appeared to be self-compatible even without the S(f)-RNase allele. The possible role of pollen- S, a presumably existing pollen component of gametophytic self-incompatibility, is discussed.

CJ-13,981 and CJ-13,982, new squalene synthase inhibitors

Two new squalene synthase (SSase) inhibitors, CJ-13,981 (I) and CJ-13,982 (II), were isolated from the fermentation broth of an unidentified fungus CL 15036. They inhibited human liver microsomal SSase with IC50s of 2.8 and 1.1 microM, respectively, but showed no inhibitory activity against human brain protein farnesyltransferase (PFTase) at 100 microM. Based on FAB-MS and NMR analyses, the structures of I and II were determined to be 3-hydroxy-3,4-dicarboxy-15-hexadecenoic acid and 3-hydroxy-3,4-dicarboxyhexadecanoic acid, respectively.

CJ-15,801, a novel antibiotic from a fungus, Seimatosporium sp

A novel antibiotic, CJ-15,801 (I), was isolated from the fermentation broth of a fungus, Seimatosporium sp. CL28611. The structure was determined to be a pantothenic acid analog having an alpha,beta-unsaturated carboxylic acid moiety by spectroscopic analyses. The compound inhibits the growth of multi-drug resistant (MDR) Staphylococcus aureus strains with MIC ranging from 6.25 to 50 microg/ml.