Practice and Safety of Static Balloon Atrial Septostomy Based on a Nationwide Registry Data.

BACKGROUND: Balloon atrial septostomy (BAS) is an essential catheterization procedure for congenital heart lesions. Recently, a balloon catheter for static BAS was approved for the first time in Japan as an alternative to the conventional pull-through BAS. Despite the expected increase in the use of static BAS, reports on its safety are scarce worldwide.Methods and Results: Data on static and pull-through BAS registered in a national registry between 2016 and 2018 were collected. During the study period, 247 sessions of static BAS and 588 sessions of pull-through BAS were performed on a total of 674 patients. Patients who underwent static BAS were older (P<0.001). The incidence of serious adverse events (4.3% vs. 0.9%, P=0.03) and the overall incidence of adverse events (8.1% vs. 3.2%, P=0.03) were higher in static BAS than in pull-through BAS. Among patients who underwent static BAS, the risk factor for adverse events was a body weight <3 kg at the time of the procedure (odds ratio: 4.3 [confidence interval: 1.7-11], P=0.003). CONCLUSIONS: This nationwide study revealed differences in patient background between static and pull-through BAS, as well as a higher incidence of adverse events related to static BAS. Patients weighing <3 kg are at high risk for adverse events after static BAS and may require surgical and circulatory support backup.

Japan-USA Orbital Atherectomy for Calcific Coronary Lesions: COAST Study, a Harmonization by Doing Proof-of-Concept: The Japanese and US Regulatory Perspective.

Regulatory approval processes for medical devices in Japan and the United States of America (US) often require similar clinical trials to establish safety and effectiveness. The Harmonization by Doing (HBD) program provides a collaborative environment for communication between regulators, academics and industry, facilitating the design and conduct of US/Japanese clinical trials supporting approval in both countries.

Recent Least Burdensome Approach for the Approval of Innovative Medical Devices in Japan -Regulatory Approval Review of an Everolimus-eluting Bioresorbable Scaffold.

Although a domestic trial in Japan revealed that Absorb bioresorbable vascular scaffold (BVS) has no inferiority to everolimus-eluting stent (EES) cohort in the primary endpoint of the target lesion failure at 12 months, the scaffold/stent thrombosis (ST) rates with the BVS at 24 months were higher than those with the EES (Absorb BVS 3.1% vs. EES 1.5%), the ST rate of 3.1% with Absorb BVS is not an acceptable level in Japan. A cause-of-ST analysis revealed that cases in which diagnostic imaging and ensuing post-dilatation had been performed appropriately had lower ST rates than those without such management (within 1 year: 1.37% vs. 7.69%, from 1 to 2 years: 0.00% vs. 8.33%). Therefore, a further evaluation was needed to confirm that the ST rate with the Absorb BVS would be reduced by a proper implementation procedure. Regulatory approval was given conditionally to initiate rigorous post-marketing data collection in order to ensure the proper use of this device in limited facilities. The One-year Use-Result Survey in Japan for the Absorb BVS revealed no instances of ST. This approach to reducing the premarket regulatory burden of clinical trials and enhancing the post-marketing commitments of medical device regulation is useful for expediting patient access to innovative medical devices.

Comparison of supportive regulatory measures for pediatric medical device development in Japan and the United States.

Further development of medical devices for children is required in Japan, but the development of such devices is delayed compared to that of medical devices for adults. Herein, we investigated policies for advancing the development of pediatric medical devices in Japan and the United States. Considering the achievements of each policy, we proposed a strategy to promote further development of pediatric medical devices in Japan. We investigated policies for supporting the development of pediatric medical devices and approved cases in Japan and the United States by searching contents of websites of regulatory bodies and other related administrations, and scientific papers. We found the main six policies in Japan and nine main policies in the United States for the development of pediatric medical devices. In the United States, various measures have initiated mainly in the 2000s, while in Japan, the main measures have been in place since 2013. Similarities were found in both countries, such as subsidies for application fees and research and development expenses, exemption of requirements for regulatory approval, and priority review and consultation by the regulatory body. Our study revealed that there are similarities in initiatives by both countries. To promote further development of pediatric medical devices in the future, improvements to expediting the review process to approval by the regulatory body, global development, and implementation of alternative measures to ensure the efficacy and safety of the device instead of large-scale clinical trials should be anticipated through cooperation among industry, government, and academia.

Differences in clinical outcomes between pre- and post-marketing clinical study following paclitaxel-coated balloon catheter treatment for coronary in-stent restenosis: from the Japanese regulatory viewpoint.

In 2013, a drug-coated balloon catheter (DCB) (SeQuent Please) for the treatment of coronary in-stent restenosis (ISR) was approved in Japan. The pre-marketing Japan domestic NP001 study demonstrated better outcomes of the DCB (n = 138) compared to plain balloon angioplasty (n = 72). After the introduction to marketing, a post-marketing surveillance (PMS) (n = 396) was conducted to evaluate the safety and efficacy of the DCB in Japanese routine clinical practice. The aim of this paper was to assess differences between the pre-marketing NP001 study and the PMS. Compared to the NP001 study, more complex lesions were treated in the PMS (type B2/C: 69.0% vs 20.4%, total occlusion: 11.2% vs 0%, p < 0.001, respectively) and target lesion was more frequently ISR related to drug-eluting stent (DES) (79.5% vs 39.4%, p < 0.001). Regarding clinical outcomes, the rate of target lesion revascularization (TLR) was higher in the PMS than in the NP001 study (TLR: 12.9% at 7 months and 17.6% at 12 months vs 2.8% at 6 months, p = 0.001, p < 0.001, respectively). Multivariable logistic regression analysis revealed that DES-ISR was a risk factor of TLR after DCB treatment for ISR (odds ratio: 5.77, 95% CI 1.75-18.95, p = 0.004). Among representative published trials using DCB for ISR, clinical outcomes are often worse in DES-ISR trials than those in bare metal stent-ISR trials. The rates of TLR in previous DES-ISR trials are similar to that in the current PMS (TLR at 12 months: 22.1% for ISAR-DESIRE 3, 15.3% for PEPCAD-DES, and 13.0% for RIBS IV). The effectiveness and safety of DCB for coronary ISR have been confirmed in the Japanese real-world survey. PMS would be useful to evaluate the safety and effectiveness of medical products throughout their total life cycles.

Independent Factors for In-Hospital Death Following Drug-Eluting Stent Thrombosis From the Japanese Adverse Event Report System.

BACKGROUND: Stent thrombosis (ST) is a serious complication after drug-eluting stents (DES) implantation. To identify the risk factors of mortality following ST, we evaluated adverse event reports used for safety measures after approval.Methods and Results:Between July 2004 and August 2019, 2,887 ST case reports were submitted to the Pharmaceutical and Medical Device Agency. Reports of probable or possible ST (n=604), with insufficient data regarding in-hospital outcome or duration between procedure and ST occurrence (n=37) or duplicate reports (n=191) were excluded. Accordingly, 2,045 reports with definite ST were analyzed. Among the subjects, there were 286 in-hospital deaths (14.0%). Multivariate logistic regression analysis revealed that left main trunk (LMT) (odds ratio [OR]: 4.76, 95% confidence interval [CI]: 3.26-6.96), chronic heart failure (CHF) (OR: 2.88, 95% CI: 1.61-5.14), hemodialysis (OR: 2.69, 95% CI: 1.66-4.36), prior stroke (OR: 2.28, 95% CI: 1.15-4.51), over 70 years old (OR: 1.62, 95% CI: 1.22-2.16), and right coronary artery (OR: 0.41, 95% CI: 0.27-0.63) were independent factors for in-hospital death after DES-ST. CONCLUSIONS: LMT, CHF, hemodialysis, prior stroke, and older age were independently associated with higher risk of in-hospital death following DES-ST. If target patients have these factors, maximum preventive strategies against ST occurrence, including adequate dual-antiplatelet therapy duration and optimal DES deployment procedures, are required.

Regulatory approval review of transcatheter mitral valve repair - Difference in the indication between the USA and Japan.

The indication for MitraClip (Abbott Vascular, Santa Clara, CA, USA) in the USA is degenerative mitral regurgitation (DMR), but the Japanese indication includes both DMR and functional mitral regurgitation (FMR), in patients without severe left ventricular dysfunction. One of the reasons for this difference is that the Japanese Circulation Society submitted a formal request to the Japanese government for early approval of MitraClip for both DMR and FMR on the basis of unmet medical need for MR patients resistant to medical therapy, but at prohibitive risk for mitral valve surgery. Here, we describe the regulatory approval review process of MitraClip in Japan. Clinical data from outside Japan indicated that MitraClip provides significant improvements from baseline in New York Heart Association Class and hospitalizations for heart failure due to the reduction of MR grade without adversely affecting long-term prognosis in FMR patients as well as DMR patients. Also, a Japanese domestic trial showed a favorable acute procedural success rate without serious adverse events with MitraClip in both DMR and FMR patients. Further, it is considered in Japan that improvement of MR mechanically is clinically important in both DMR and FMR, in patients without severe left ventricular dysfunction. On the basis of these considerations, the MitraClip was approved in Japan for indications of both DMR and FMR with preserved cardiac function in patients at prohibitive risk for mitral valve surgery.

Learning Curve for Transcatheter Aortic Valve Implantation Under a Controlled Introduction System　- Initial Analysis of a Japanese Nationwide Registry.

BACKGROUND: The introduction of transcatheter aortic valve implantation (TAVI) into Japan was strictly controlled to optimize patient outcomes. The goal of this study was to assess if increasing experience during the introduction of this procedure was associated with outcomes.Methods and Results:The initial 1,752 patients registered in the Japanese national TAVI registry were included in the study. The association between operator procedure number and incidence of the early safety endpoint at 30 days (ESE30) as defined in the Valve Academic Research Consortium-2 consensus document was evaluated. Patients were divided into 4 groups by quartiles of procedure count (Groups I-IV in order of increasing number of procedures). Median patient age was 85 years, and 30.5% were male. The 30-day mortality rate was 1.4% (n=24), and 78 patients (7.9%) experienced 95 ESE30. Among the variables included in the model, ESE30 was associated with non-transfemoral approach (P=0.004), renal dysfunction (Cr >2.0 mg/dL) (P=0.01) and NYHA class III/IV (P=0.04). ESE30 incidence was not significantly different between Groups I-III and Group IV. Spline plots demonstrated that experience of 15-20 cases in total was needed to achieve a consistent low risk of ESE30. CONCLUSIONS: Increasing experience was associated with better outcomes, but to a lesser degree than in previous reports. Our findings suggested that the risks associated with the learning curve process were appropriately mitigated.

First Approval of Improved Medical Device Conditional on Use-Result Survey in Japan　- Regulatory Review of Polymer-Free Drug-Coated BioFreedom Coronary Stent.

A prospective randomized clinical trial showed that the BioFreedom stent (Biosensors International), which is a polymer-free and carrier-free drug-coated stent, was significantly superior to a bare-metal stent (BMS) in patients at high bleeding risk who were receiving a 1-month course of dual antiplatelet therapy (DAPT). However, the stent thrombosis rate (2.01% for BioFreedom vs. 2.20% for BMS) was 4-6-fold higher than that of approved drug-eluting stents based on real-world data in Japan. Furthermore, the frequency of stent thrombosis at more than 1 month with the BioFreedom stent was slightly higher than that at less than 1 month. This result suggested that it would not be acceptable to stop DAPT universally at 1 month. Thus, the target patients for the BioFreedom stent are unspecified patients at high bleeding risk needing to continue DAPT for as long as necessary in Japan. Therefore, based on the pre- and post-marketing balance of medical devices regulations, regulatory approval was given for unspecified patients conditionally upon real-world data collection of 2,000 patients with a Use-Results Survey, instead of conducting additional pre-marketing clinical trial(s). The Use-Results Survey System is part of a strategy to expedite patients' access to innovative medical devices and to accelerate the development of medical devices.

Coordinated regulation of differentiation and proliferation of embryonic cardiomyocytes by a jumonji (Jarid2)-cyclin D1 pathway.

In general, cell proliferation and differentiation show an inverse relationship, and are regulated in a coordinated manner during development. Embryonic cardiomyocytes must support embryonic life by functional differentiation such as beating, and proliferate actively to increase the size of the heart. Therefore, progression of both proliferation and differentiation is indispensable. It remains unknown whether proliferation and differentiation are related in these embryonic cardiomyocytes. We focused on abnormal phenotypes, such as hyperproliferation, inhibition of differentiation and enhanced expression of cyclin D1 in cardiomyocytes of mice with mutant jumonji (Jmj, Jarid2), which encodes the repressor of cyclin D1. Analysis of Jmj/cyclin D1 double mutant mice showed that Jmj was required for normal differentiation and normal expression of GATA4 protein through cyclin D1. Analysis of transgenic mice revealed that enhanced expression of cyclin D1 decreased GATA4 protein expression and inhibited the differentiation of cardiomyocytes in a CDK4/6-dependent manner, and that exogenous expression of GATA4 rescued the abnormal differentiation. Finally, CDK4 phosphorylated GATA4 directly, which promoted the degradation of GATA4 in cultured cells. These results suggest that CDK4 activated by cyclin D1 inhibits differentiation of cardiomyocytes by degradation of GATA4, and that initiation of Jmj expression unleashes the inhibition by repression of cyclin D1 expression and allows progression of differentiation, as well as repression of proliferation. Thus, a Jmj-cyclin D1 pathway coordinately regulates proliferation and differentiation of cardiomyocytes.

A jumonji (Jarid2) protein complex represses cyclin D1 expression by methylation of histone H3-K9.

Covalent modifications of histone tails have critical roles in regulating gene expression. Previously, we identified the jumonji (jmj, Jarid2) gene, the jmjC domain, and a Jmj family. Recently, many Jmj family proteins have been shown to be histone demethylases, and jmjC is the catalytic domain. However, Jmj does not have histone demethylase activity because the jmjC domain lacks conserved residues for binding to cofactors. Independently of these studies, we previously showed that Jmj binds to the cyclin D1 promoter and represses the transcription of cyclin D1. Here, we show the mechanisms by which Jmj represses the transcription of cyclin D1. We found that a protein complex of Jmj had histone methyltransferase activity toward histone H3 lysine 9 (H3-K9). We also found that Jmj bound to the H3-K9 methyltransferases G9a and GLP. Expression of Jmj recruited G9a and GLP to the cyclin D1 promoter and increased H3-K9 methylation. Inactivation of both G9a and GLP, but not of only G9a, inhibited the methylation of H3-K9 in the cyclin D1 promoter and repression of cyclin D1 expression by Jmj. These results suggest that Jmj methylates H3-K9 and represses cyclin D1 expression through G9a and GLP, and that Jmj family proteins can regulate gene expression by not only histone demethylation but also other histone modification.

Impaired differentiation of fetal hepatocytes in homozygous jumonji mice.

Homozygous jumonji (jmj(-)/jmj(-)) mice were previously shown to exhibit hepatic hypoplasia and defective hematopoiesis in the liver and die at around embryonic day 15.5 (E15.5), suggesting that jmj is essential for liver development. In order to gain insight into the mechanism of liver development, we analyzed the expression and function of jmj in fetal hepatocytes. The number of hepatocytes in jmj(-)/jmj(-) mice was markedly reduced in comparison with control mice and the expression of jmj in hepatocytes increased along with development. As jmj(-)/jmj(-) embryos die by E15.5, we employed an in vitro culture system in which fetal hepatocytes differentiate in response to oncostatin M. The proliferation potential of jmj(-)/jmj(-) hepatocytes was comparable to that of wild type cells in vitro, however maturation of hepatocytes as evidenced by the expression of liver enzymes such as tyrosine amino transferase was severely impaired by the jmj gene inactivation. These results suggested that jmj plays a pivotal role in the development of mid-fetal hepatocytes to the neonatal stage.

Scapinin, a putative protein phosphatase-1 regulatory subunit associated with the nuclear nonchromatin structure.

It is thought that the nuclear nonchromatin structures, such as the nuclear matrix and lamina, play regulatory roles in gene expression. In this study, we identified an insoluble protein that was associated with the chromatin-depleted nuclear structure of proliferating human leukemia HL-60 cells. Preparation of the chromatin-depleted nuclear structure, referred to as the nuclear matrix-intermediate filament scaffold (Fey, E., Krochmalnic, G., and Penman, S. (1986) J. Cell. Biol. 102, 1654-1665), involved cell extraction using a series of buffers containing Triton X-100, DNase I, and 2 M NaCl. A yeast two-hybrid assay revealed that this protein bound to the catalytic subunit of protein phosphatase-1 (PP1). Furthermore, it inhibited PP1 activity in vitro. We therefore named it scapinin (scaffold-associated PP1 inhibiting protein). cDNA cloning revealed that scapinin had two splicing variants of 448 amino acids (scapinin-S) and 518 amino acids (scapinin-L). Scapinin was down-regulated by differentiation in HL-60 cells. These results suggest that scapinin is a putative regulatory subunit of PP1 and is involved in transformed or immature phenotypes of HL-60 cells. We also describe the presence of scapinin family proteins from worm to human.

jumonji downregulates cardiac cell proliferation by repressing cyclin D1 expression.

Spatiotemporal regulation of cell proliferation is necessary for normal tissue development. The molecular mechanisms, especially the signaling pathways controlling the cell cycle machinery, remain largely unknown. Here, we demonstrate a negative relationship between the spatiotemporal patterns of jumonji (jmj) expression and cardiac myocyte proliferation. cyclin D1 expression and cell proliferation are enhanced in the cardiac myocytes of jmj-deficient mutant embryos. In contrast, jmj overexpression represses cyclin D1 expression in cardiac cells, and Jmj protein binds to cyclin D1 promoter in vivo and represses its transcriptional activity. cyclin D1 overexpression causes hyperproliferation in the cardiac myocytes, but the absence of cyclin D1 in jmj mutant embryos rescues the hyperproliferation. Therefore, Jmj might control cardiac myocyte proliferation and consequently cardiac morphogenesis by repressing cyclin D1 expression.