Impact of Tweet Content on the Number of Retweets - "Tweet the Meeting 2022"

Background: Previous research has investigated the effectiveness of the "Tweet the Meeting" campaign, but the relationship between tweet content and the number of retweets has not been fully evaluated. Methods and Results: We analyzed the number of tweets and retweets during the Japanese Circulation Society's 2022 annual meeting. The ambassador group had significantly more session- and symposium-related tweets than the non-ambassador group (P<0.001), associated with the nubmer of retweets. Symposium-related tweets with figures generated more retweets than those without figures (mean [±SD] 3.47±3.31 vs. 2.48±1.94 retweets per tweet, respectively; P=0.001). Conclusions: The study revealed that official meeting-designated Twitter ambassadors disseminate more educational content than non-ambassadors, and generated more retweets.

Difficulties in ensuring review quality performed by committees under the Act on the Safety of Regenerative Medicine in Japan

We outlined five studies regarding the quality of the review by committees based on the Act on the Safety of Regenerative Medicine. The findings raise serious concerns about the independence, integrity, and quality of reviews of therapeutic plans by these committees with inappropriately close relationships to medical institutions and companies.

A cross-sectional survey on principal investigators' clinical research knowledge in Japan

Principal investigators (PIs) play a key role in clinical research, and must thus understand the role of clinical research support staff to conduct successful and appropriate clinical research. This study evaluates clinical research capabilities by examining the clinical research knowledge of PIs and clinical research support staff. The participants of this cross-sectional study were academic researchers and clinical research support staff from Japanese universities and research institutions. The participants comprised of 54 respondents, among whom 36 were PIs (physicians) and 18 were clinical research support staff. A self-administered electronic survey was created and evaluated by experts, with 50 knowledge items. Mann-Whitney U tests were used to determine the significance of the differences in knowledge between clinical research support staff and PIs. We compared the correct answer rate of clinical research support staff and PIs for each knowledge category and observed that the clinical research support staff scored significantly higher than the PIs in all aspects of clinical research knowledge sections, including total score. Our findings showed that PIs did not have the same amount of clinical research knowledge as the clinical research support staff. Clinical research knowledge is essential for investigators, especially PIs, to protect patients and promote medical breakthroughs. Thus, more accessible clinical research education and mandatory knowledge testing will allow PIs to lead successful clinical research and further the level of medical research in Japan.

The association between research funding status and clinical research papers’ citation impact in Japan: A cross-sectional bibliometric study

Introduction

Studies have not sufficiently clarified the differences in citation impact between funded and non-funded clinical research papers. Hence, this study seeks to evaluate the relation between research funding status and clinical research papers’ citation impact in different research fields using multiple evaluation indices.

Methods

In this cross-sectional bibliometric study, clinical research papers published by core clinical research hospitals in Japan were compared retrospectively in terms of times cited (TC), category normalized citation impact (CNCI), citation percentile (CP), journal impact factor (JIF), the Software to Identify, Manage, and Analyze Scientific Publications (SIGAPS) category, and whether they were the funded clinical research. The association between research funding status or the SIGAPS category and CNCI ≥ 2 was analyzed using logistic regression analysis.

Results

11 core clinical research hospitals published 553 clinical research papers, of which 120 were non-funded and 433 were funded (public institution-funded and industry-funded). The study found that funded clinical research papers (public institution-funded and industry-funded) had significantly higher TC, CNCI, CP, and JIF than non-funded ones [TC: 8 (3–17) vs. 14 (8–31), p < 0.001; CNCI: 0.53 (0.19–0.97) vs. 0.87 (0.45–1.85), p < 0.001; CP: 51.9 (24.48–70.42) vs. 66.7 (40.53–88.01), p < 0.001; JIF: 2.59 (1.90–3.84) vs. 2.93 (2.09–4.20) p = 0.008], while the proportion of A or B rank clinical research papers of the SIGAPS category was not significantly different between the two groups (30.0 vs. 34.9%, p = 0.318). In the logistic regression analysis, having a CNCI ≥ 2 was significantly associated with research funding (public institution-funded and industry-funded) and publication in A or B rank journals of the SIGAPS category [research funding: Estimate 2.169, 95% confidence interval (CI) 1.153–4.083, p = 0.016; SIGAPS category A/B: Estimate 6.126, 95% CI 3.889–9.651, p < 0.001].

Conclusion

Analysis via multiple indicators including CNCI and the SIGAPS category, which allows for a comparison of the papers’ citation impact in different research fields, found a positive relation between research funding status and the citation impact of clinical research papers.

Factors Associated With the Acceleration of Patient Enrollment in Clinical Studies: A Cross-Sectional Study

Under-recruitment in clinical trials is an issue worldwide. If the number of patients enrolled is lower than expected, based on the required sample size, then the reliability of the study results and their validation tend to be impaired. The current study therefore evaluated factors associated with accelerating patient enrollment using data from an ongoing multicenter prospective cohort study. The researchers encouraged research institutions to accelerate patient enrollment via e-mail, newsletters, telephone calls, and site visits. We analyzed the relationship between several potential factors associated with acceleration of patient enrollment including site visits and patient enrollment in a real clinical study. Data were collected from 106 research institutions that participated in a multicenter prospective cohort study. Results showed that the following parameters differed in terms of patient enrollment and non-enrollment: urban area (47.2 vs. 67.6%, p = 0.04), clinical research coordinator (CRC) participation in data input to electronic data capture (EDC) (41.7 vs. 11.8%, p < 0.01), and site visit (38.9 vs. 11.8%, p < 0.01). A multivariate analysis revealed that patient enrollment was significantly associated with urban area (odds ratio [OR] 0.33, 95% confidence interval [CI] 0.12–0.86, p = 0.02), CRC participation in data input to EDC (OR 5.02; 95% CI 1.49–16.8; p < 0.01), and site visit (OR 4.54, 95% CI 1.31–15.7, p = 0.01). In conclusion, site visits and CRC participation in data input to EDC had a significant effect on patient enrollment promotion. Moreover, hospitals in rural areas were more effective in promoting patient enrollment than those in urban areas.

Relationship Between Official Twitter Ambassadors and the Number of Retweets in the Annual Congress - "Tweet the Meeting"

Background: The relationship between Twitter ambassadors and retweets has not been fully evaluated for “tweet the meeting” activity.

Methods and Results: We collected data on the number of tweets and retweets during the Japanese Circulation Society’s (JCS) annual meetings in 2019, 2020, and 2021. After adjustment, JCS Twitter Ambassadors, selected by the JCS to increase the meeting’s visibility, increased the total number of retweets by 9%.

Conclusions: This is the first report on the numerical relationship between JCS Twitter Ambassadors and the total number of retweets during an annual congress. Original tweets by JCS Twitter Ambassadors increased the number of retweets, but retweets by influencers were more effective at stimulating social media engagement.

Effect of Empagliflozin as an Add-On Therapy on Decongestion and Renal Function in Patients With Diabetes Hospitalized for Acute Decompensated Heart Failure: A Prospective Randomized Controlled Study

BACKGROUND

Empagliflozin reduces the risk of hospitalization for heart failure in patients with type 2 diabetes and cardiovascular disease. We sought to elucidate the effect of empagliflozin as an add-on therapy on decongestion and renal function in patients with type 2 diabetes admitted for acute decompensated heart failure.

METHODS

The study was terminated early due to COVID-19 pandemic. We enrolled 59 consecutive patients with type 2 diabetes admitted for acute decompensated heart failure. Patients were randomly assigned to receive either empagliflozin add-on (n=30) or conventional glucose-lowering therapy (n=29). We performed laboratory tests at baseline and 1, 2, 3, and 7 days after randomization. Percent change in plasma volume between admission and subsequent time points was calculated using the Strauss formula.

RESULTS

There were no significant baseline differences in left ventricular ejection fraction and serum NT-proBNP (N-terminal pro-B-type natriuretic peptide), hematocrit, or serum creatinine levels between the 2 groups. Seven days after randomization, NT-proBNP level was significantly lower in the empagliflozin group than in the conventional group (P=0.040), and hemoconcentration (≥3% absolute increase in hematocrit) was more frequently observed in the empagliflozin group than in the conventional group (P=0.020). The decrease in percent change in plasma volume between baseline and subsequent time points was significantly larger in the empagliflozin group than in the conventional group 7 days after randomization (P=0.017). The incidence of worsening renal function (an increase in serum creatinine ≥0.3 mg/dL) did not significantly differ between the 2 groups.

CONCLUSIONS

In this exploratory analysis, empagliflozin achieved effective decongestion without an increased risk of worsening renal function as an add-on therapy in patients with type 2 diabetes with acute decompensated heart failure. Registration: URL: https://www.umin.ac.jp/ctr/index.htm; Unique identifier: UMIN000026315.

Performance Index for Types of Clinical Research Support Service Providers for Academic Research Organizations in Japan: A Cross-Sectional Survey

The purpose of this study was to conduct a factual survey to evaluate the type of clinical research support offered by service providers (supporters) in Japanese academic research organizations (AROs). From September to October 2018, we conducted an online questionnaire targeting researchers and supporters of AROs, including individuals supporting research and development (R&D) planning, as well as those involved in study management, biostatistics, coordination, data management, monitoring, and auditing. The number of responses was tabulated for each survey item. For items with written descriptions, we compiled summaries using the inductive regression method of qualitative research. Responses were obtained from 124 researchers, 258 supporters, and 40 AROs. None of the institutions responded that they had a performance index for all types of service providers, whereas 47% of institutions had an index for 1-3 types of service providers, and 40% of institutions had no index. Many institutions responded that they had a performance index for coordinators and data management, but few responded that there was a performance index for individuals engaged in R&D and study management. Furthermore, for all evaluations of AROs and researchers, the level of supporter satisfaction was low at only 20%. There was a discrepancy between the levels of researcher expectations and the actual contribution of R&D in the process of research planning. Our survey revealed that there is currently no performance index for services supporting clinical research. In future studies, we need to examine a performance index that accurately reflects the researcher attitudes revealed in this study.

Cardiology Department Practices in the First Wave of the Coronavirus Disease Pandemic - A Nationwide Survey in Japan by the Japanese Circulation Society

Background: From the early phase of the Coronavirus disease-2019 (COVID-19) pandemic, cardiologists have paid attention not only to COVID-19-associated cardiovascular sequelae, but also to treatment strategies for rescheduling non-urgent procedures. The chief objective of this study was to explore confirmed COVID-19 cardiology case experiences and departmental policies, and their regional heterogeneity in Japan.

Methods and Results: We performed a retrospective analysis of a nationwide survey performed by the Japanese Circulation Society on April 13, 2020. The questionnaire included cardiology department experience with confirmed COVID-19 cases and restriction policies, and was sent to 1,360 certified cardiology training hospitals. Descriptive analysis and spatial autocorrelation analysis of each response were performed to reveal the heterogeneity of departmental policies. The response rate was 56.8% (773 replies). Only 16% of all responding hospitals experienced a COVID-19 cardiology case. High-risk procedures were restricted in more than one-fifth of hospitals, including transesophageal echocardiography (34.9%) and scheduled catheterization (39.5%). The presence of a cardiologist in the COVID-19 team, the number of board-certified cardiologists, any medical resource shortage and a state of emergency were positively correlated with any type of restriction.

Conclusions: We found both low clinical case experiences with COVID-19 and restrictions of cardiovascular procedures during the first COVID-19 wave in Japan. Restrictions arising as a result of COVID-19 were affected by hospital- and country-level variables, such as a state of emergency.

Cardiology Department Policy in Japan After Coronavirus Disease-2019 (COVID-19) - Descriptive Summary of 2nd Nationwide Survey by the Japanese Circulation Society

Background: Cardiovascular department restriction policies on procedures resulting from the COVID-19 pandemic have not been fully evaluated.

Methods and Results: We performed a retrospective analysis of a nationwide survey performed by the Japanese Circulation Society in August 2020. The total response rate was 48.9% (651/1,331). The rate of restriction of cardiovascular procedures peaked in April. Exacerbations of heart failure due to hospital restrictions were noted in 43.8% of departments.

Conclusions: Many departments restricted their cardiological procedures, and this rate changed according to the pandemic situation. The exacerbation of cardiovascular disease resulting from pandemic restrictions should not be ignored.

Two-Year Experience in "Tweeting the Meeting" During the Scientific Sessions - Rapid Report From the Japanese Circulation Society

Background: Twitter has become increasingly popular at annual medical congresses as a platform to communicate to attendees. The aim of this study is to reveal the twitter usage in the annual congress of the Japanese Cirsulation Society. Methods and Results: We compared the total number of tweets during the Japanese Circulation Society's annual meetings in 2019 and 2020. The total number of tweets increased from 7,587 in 2019 to 23,867 in 2020. Most tweets were retweets (>70%), and approximately half of Twitter users tweeted only once. Conclusions: Twitter usage during the Japanese Circulation Society's annual meeting increased from 2019 to 2020, and a large number of tweets were from Twitter ambassadors of the Japanese Circulation Society. However, further evaluation is needed, with future studies investigating the usefulness of this platform.

Recommendations for Maintaining the Cardiovascular Care System Under the Conditions of the COVID-19 Pandemic - 1st Edition, April 2020

BACKGROUND

The Japanese Circulation Society proposes recommendations for all healthcare professionals involved in cardiovascular medicine to protect them from infection and ensure that seriously ill patients requiring urgent care receive proper treatment.Methods and Results:Patients are divided into "Positive or suspected coronavirus disease 2019 (COVID-19)" and "All others". Furthermore, tests and treatments are divided into emergency or standby. For each category, we propose recommendations.

CONCLUSIONS

To maintain the cardiovascular care system, The Japanese Circulation Society recommends completely preventing nosocomial COVID-19 infections, ensuring adequate PPE necessary for healthcare personnel, and learning and implementing standard precautions.

A Concept for a Japanese Regulatory Framework for Emerging Medical Devices with Frequently Modified Behavior

Recent progress in the Internet of Things and artificial intelligence has made it possible to utilize the vast quantity of personal health records, clinical data, and scientific findings for prognosis, diagnosis, and therapy. These innovative technologies provide new possibilities with the development of medical devices (MDs), whose behaviors can be continuously modified. A novel regulatory framework covering these MDs is now under discussion in Japan. In this review, we introduce the regulatory initiative for MDs and the importance of a paradigm shift from regulation to innovation regarding MDs.

Coronavirus Disease 2019 (COVID-19) Information for Cardiologists - Systematic Literature Review and Additional Analysis

BACKGROUND

Despite the rapidly increasing attention being given to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection, more commonly known as coronavirus disease 2019 (COVID-19), the relationship between cardiovascular disease and COVID-19 has not been fully described.Methods and Results:A systematic review was undertaken to summarize the important aspects of COVID-19 for cardiologists. Protection both for patients and healthcare providers, indication for treatments, collaboration with other departments and hospitals, and regular update of information are essentials to front COVID-19 patients.

CONCLUSIONS

Because the chief manifestations of COVID-19 infection are respiratory and acute respiratory distress syndrome, cardiologists do not see infected patients directly. Cardiologists need to be better prepared regarding standard disinfection procedures, and be aware of the indications for extracorporeal membrane oxygenation and its use in the critical care setting.

Advanced Medical Care Program for the Rapid Introduction of Healthcare Technologies to the National Health Insurance System in Japan

Japan's Advanced Medical Care Program (AMCP) seeks to facilitate patient access to promising healthcare technologies through National Health Insurance (NHI) coverage. This study aimed to examine AMCP's contribution to the accelerated introduction of new technologies through NHI coverage. AMCP-type B technologies registered May 2006-March 2019 were examined. To investigate the use of AMCP for NHI coverage, data from the AMCP website and from regulatory authority documents were used. Of 127 AMCP-type B technologies, 38 underwent final review. Fifteen technologies were successfully introduced into NHI coverage. Eight technologies introduced directly through the Advanced Medical Care Conference were related to medical devices. Other technologies, including drugs, required additional accelerated frameworks for market approval. A strategic approach with the careful selection of target therapeutic technologies and accelerated frameworks is key for the rapid introduction of medical technologies through AMCP.

Importance of Quality Assessment in Clinical Research in Japan

Background: The number of papers published by an institution is acknowledged as an easy-to-understand research outcome. However, the quantity as well as the quality of research papers needs to be assessed. Methods: To determine the relation between the number of published papers and paper quality, a survey was conducted to assess publications focusing on interventional clinical trials reported by 11 core clinical research hospitals. A score was calculated for each paper using Système d'interrogation, de gestionet d'analyse des publications scientifiques scoring system, allowing for a clinical paper quality assessment independent of the field. Paper quality was defined as the relative Journal impact factor (IF) total score/number of papers. Results: We surveyed 580 clinical trial papers. For each of the 11 medical institutions (a-k), respectively, the following was found: number of published papers: a:66, b:64, c:61, d:56, e:54, f:51, g:46, h:46, i:46, j:45, k:45 (median: 51, maximum: 66, minimum: 45); total Journal IF: a:204, b:252, c:207, d:225, e:257, f:164, g:216, h:190, i:156, j:179, k:219 (median: 207, maximum: 257, minimum: 156); relative Journal IF total score: a:244, b:272, c:260, d:299, e:268, f:215, g:225, h:208, i:189, j:223, k:218 (median: 225, maximum: 299, minimum: 189); and paper quality (relative Journal IF total score/number of papers): a:3.70, b:4.25, c:4.26, d:5.34, e:4.96, f:4.22, g:4.89, h:4.52, i:4.11, j:4.96, k:4.84 (median: 4.52, maximum: 5.34, minimum: 3.70). Additionally, no significant relation was found between the number of published papers and paper quality (correlation coefficient, -0.33, P = 0.32). Conclusions: The number of published papers does not correspond to paper quality. When assessing an institution's ability to perform clinical research, an assessment of paper quality should be included along with the number of published papers.

Potential Role of Twitter at an Annual Congress in Japan - Narrative Literature Review of "Tweet the Meeting"

Background: Twitter has become increasingly popular at annual medical congresses as a platform to communicate to attendees. In contrast, Twitter is not as frequently used in Japan as compared with other countries. Herein, we reviewed the literature and discuss the potential role and risks of “tweet the meeting” in Japan.

Methods and Results: We performed a literature review to consider the recent trend of tweeting the meeting, including benefits and how to tweet, as well as potential risks. Upon officially deciding to tweet the meeting, a number of societies and professional organizations developed strategies to enhance the attendees’ experience using multiple modalities and guides. Although there are several risks, we provide a concise guide to tweeting the meeting for the Japanese audience, which could be useful for understanding what should be done before and during a conference.

Conclusions: The use of Twitter at medical congresses has many possibilities, and there are numerous potentials in many areas. We should discuss this in the light of the benefits for congress attendees in Japan.

Identification of the Mtus1 Splice Variant as a Novel Inhibitory Factor Against Cardiac Hypertrophy

Background

In cardiac hypertrophy and failure, there is a widespread alteration in mRNA splicing, but the role of splice variants in cardiac hypertrophy has not yet been fully elucidated. In this study, we used an exon array to identify novel splice variants associated with cardiac hypertrophy.

Methods and Results

We performed genome‐wide exon array analysis and developed a splicing profile in murine hearts with hypertrophy induced by transverse aortic constriction for 8 weeks. Following global analysis of splice variants using the Mouse Exon 1.0 ST Array, we identified 46 spliced genes and narrowed our focus to 1 gene, mitochondrial tumor suppressor 1 (Mtus1), whose splice variants were registered in the NCBI RefSeq database. Notably, one of the splice variants Mtus1A was specifically upregulated, although the total expression of the Mtus1 gene remained unchanged. We showed that Mtus1A was localized in the mitochondria, and its expression level increased with the degree of cardiac hypertrophy. In cultured cardiomyocytes, Mtus1A overexpression reduced phenylephrine‐induced reactive oxygen species production and consequent ERK phosphorylation, resulting in a decrease in both cell size and protein synthesis. In vivo, cardiac‐specific Mtus1A transgenic mice showed left ventricle wall thinning and a reduced hypertrophic response to pressure overload and phenylephrine treatment.

Conclusions

We found that Mtus1 is specifically spliced in hypertrophic hearts and that the Mtus1A variant has an inhibitory effect on cardiac hypertrophy. Mtus1A is, therefore, a possible diagnostic and therapeutic target for cardiac hypertrophy and failure.

Chemical Endoplasmic Reticulum Chaperone Alleviates Doxorubicin-Induced Cardiac Dysfunction

RATIONALE

Doxorubicin is an effective chemotherapeutic agent for cancer, but its use is often limited by cardiotoxicity. Doxorubicin causes endoplasmic reticulum (ER) dilation in cardiomyocytes, and we have demonstrated that ER stress plays important roles in the pathophysiology of heart failure.

OBJECTIVE

We evaluated the role of ER stress in doxorubicin-induced cardiotoxicity and examined whether the chemical ER chaperone could prevent doxorubicin-induced cardiac dysfunction.

METHODS AND RESULTS

We confirmed that doxorubicin caused ER dilation in mouse hearts, indicating that doxorubicin may affect ER function. Doxorubicin activated an ER transmembrane stress sensor, activating transcription factor 6, in cultured cardiomyocytes and mouse hearts. However, doxorubicin suppressed the expression of genes downstream of activating transcription factor 6, including X-box binding protein 1. The decreased levels of X-box binding protein 1 resulted in a failure to induce the expression of the ER chaperone glucose-regulated protein 78 which plays a major role in adaptive responses to ER stress. In addition, doxorubicin activated caspase-12, an ER membrane-resident apoptotic molecule, which can lead to cardiomyocyte apoptosis and cardiac dysfunction. Cardiac-specific overexpression of glucose-regulated protein 78 by adeno-associated virus 9 or the administration of the chemical ER chaperone 4-phenylbutyrate attenuated caspase-12 cleavage, and alleviated cardiac apoptosis and dysfunction induced by doxorubicin.

CONCLUSIONS

Doxorubicin activated the ER stress-initiated apoptotic response without inducing the ER chaperone glucose-regulated protein 78, further augmenting ER stress in mouse hearts. Cardiac-specific overexpression of glucose-regulated protein 78 or the administration of the chemical ER chaperone alleviated the cardiac dysfunction induced by doxorubicin and may facilitate the safe use of doxorubicin for cancer treatment.

Carperitide induces coronary vasodilation and limits infarct size in canine ischemic hearts: role of NO

Carperitide is effective for heart failure (HF) owing to its diuretic and vasodilatory effects. This recombinant peptide may also have direct cardioprotective effects because carperitide reduces the severity of heart failure and limits infarct size. Because coronary vasodilation is an important cardioprotective treatment modality, we investigated whether carperitide increased coronary blood flow (CBF) and improved myocardial metabolic and contractile dysfunction during ischemia in canine hearts. We also tested whether carperitide is directly responsible for limiting the infarct size. We infused carperitide at 0.025-0.2 μg kg(-1) min(-1) into the canine coronary artery. A minimum dose of 0.1 μg kg(-1) min(-1) was required to obtain maximal vasodilation. To test the effects of carperitide on ischemic hearts, we reduced perfusion pressure in the left anterior descending coronary artery such that CBF decreased to one-third of the baseline value. At 10 min after carperitide was infused at a dose of 0.1 μg kg(-1) min(-1), we observed increases in CBF, fractional shortening (FS) and pH levels in coronary venous blood without concomitant increases in cardiac nitric oxide (NO) levels; these changes were attenuated using either the atrial natriuretic peptide receptor antagonist HS-142-1 or the NO synthase inhibitor L(ω)-nitroarginine methyl ester (L-NAME). Cyclic guanosine monophosphate (GMP) levels in the coronary artery were elevated in response to carperitide that also limited the infarct size after 90 min of ischemia and subsequent reperfusion. Again, these effects were blunted by L-NAME. Carperitide increases CBF, reduces myocardial contractile and metabolic dysfunction and limits infarct size. In addition, NO is necessary for carperitide-induced vasodilation and cardioprotection in ischemic hearts.

Dipeptidyl-peptidase IV inhibition improves pathophysiology of heart failure and increases survival rate in pressure-overloaded mice

Incretin hormones, including glucagon-like peptide-1 (GLP-1), a target for diabetes mellitus (DM) treatment, are associated with cardioprotection. As dipeptidyl-peptidase IV (DPP-IV) inhibition increases plasma GLP-1 levels in vivo, we investigated the cardioprotective effects of the DPP-IV inhibitor vildagliptin in a murine heart failure (HF) model. We induced transverse aortic constriction (TAC) in C57BL/6J mice, simulating pressure-overloaded cardiac hypertrophy and HF. TAC or sham-operated mice were treated with or without vildagliptin. An intraperitoneal glucose tolerance test revealed that blood glucose levels were higher in the TAC than in sham-operated mice, and these levels improved with vildagliptin administration in both groups. Vildagliptin increased plasma GLP-1 levels in the TAC mice and ameliorated TAC-induced left ventricular enlargement and dysfunction. Vildagliptin palliated both myocardial apoptosis and fibrosis in TAC mice, demonstrated by histological, gene and protein expression analyses, and improved survival rate on day 28 (TAC with vildagliptin, 67.5%; TAC without vildagliptin, 41.5%; P < 0.05). Vildagliptin improved cardiac dysfunction and overall survival in the TAC mice, both by improving impaired glucose tolerance and by increasing GLP-1 levels. DPP-IV inhibitors represent a candidate treatment for HF patients with or without DM.

Smoking promotes subclinical atherosclerosis in apparently healthy men: 2-year ultrasonographic follow-up

BACKGROUND

Smoking is a major risk factor for cardiovascular disease. Also, inflammatory activation and metabolic disorder are the mediators of smoking-induced atherosclerotic progression. The aim of the present study was to investigate whether current smoking and smoking cessation alter inflammatory or metabolic status and affect subclinical atherosclerosis in apparently healthy men.

METHODS AND RESULTS

Classical risk factors and smoking habit were evaluated in 354 men who completed health examinations annually without any current medications. Carotid intima-media thickness (IMT) was followed for 27.1±4.5 months. At baseline, both maximum and mean IMT significantly changed during 2-year follow-up. They tended to increase along with progression of smoking habit, with significantly greater maximum IMT in current smokers compared with never smokers. Both maximum and mean IMT significantly changed during 2-year follow-up, and tended to increase with progression of smoking habit, with maximum IMT being greatest for current smokers. Past smokers tended to have greater IMT increase than never smokers. Among smoking habit and some atherosclerotic risk markers that showed significant correlation with maximum IMT increase, stepwise regression showed that smoking habit and serum low-density lipoprotein-cholesterol (LDL-C) level were the only independent predictors.

CONCLUSIONS

Significant 2-year progression of subclinical atherosclerosis was associated with continuous smoking and LDL-C. This was only partly moderated in past smokers despite complete reversal of inflammatory activation, suggesting another crucial factor for inhibiting accelerated progression of subclinical atherosclerosis in men.

Pathophysiology of myocardial reperfusion injury: preconditioning, postconditioning, and translational aspects of protective measures

Heart diseases due to myocardial ischemia, such as myocardial infarction or ischemic heart failure, are major causes of death in developed countries, and their number is unfortunately still growing. Preliminary exploration into the pathophysiology of ischemia-reperfusion injury, together with the accumulation of clinical evidence, led to the discovery of ischemic preconditioning, which has been the main hypothesis for over three decades for how ischemia-reperfusion injury can be attenuated. The subcellular pathophysiological mechanism of ischemia-reperfusion injury and preconditioning-induced cardioprotection is not well understood, but extensive research into components, including autacoids, ion channels, receptors, subcellular signaling cascades, and mitochondrial modulators, as well as strategies for modulating these components, has made evolutional progress. Owing to the accumulation of both basic and clinical evidence, the idea of ischemic postconditioning with a cardioprotective potential has been discovered and established, making it possible to apply this knowledge in the clinical setting after ischemia-reperfusion insult. Another a great outcome has been the launch of translational studies that apply basic findings for manipulating ischemia-reperfusion injury into practical clinical treatments against ischemic heart diseases. In this review, we discuss the current findings regarding the fundamental pathophysiological mechanisms of ischemia-reperfusion injury, the associated protective mechanisms of ischemic pre- and postconditioning, and the potential seeds for molecular, pharmacological, or mechanical treatments against ischemia-reperfusion injury, as well as subsequent adverse outcomes by modulation of subcellular signaling mechanisms (especially mitochondrial function). We also review emerging translational clinical trials and the subsistent clinical comorbidities that need to be overcome to make these trials applicable in clinical medicine.

A histamine H₂ receptor blocker ameliorates development of heart failure in dogs independently of β-adrenergic receptor blockade

Histamine has a positive inotropic effect on ventricular myocardium and stimulation of histamine H₂ receptors increases the intracellular cAMP level via Gs protein, as dose stimulation of β-adrenergic receptors, and worsens heart failure. To test whether a histamine H₂ receptor blocker had a beneficial effect in addition to β-adrenergic receptor blockade, we investigated the cardioprotective effect of famotidine, a histamine H₂ receptor blocker, in dogs receiving a β-blocker. We induced heart failure in dogs by rapid ventricular pacing (230 beats/min). Animals received no drugs (control group), famotidine (1 mg/kg daily), carvedilol (0.1 mg/kg daily), or carvedilol plus famotidine. Both cardiac catheterization and echocardiography were performed before and 4 weeks after the initiation of pacing. Immunohistochemical studies showed the appearance of mast cells and histamine in the myocardium after 4 weeks of pacing. In the control group, the left ventricular ejection fraction (LVEF) was decreased after 4 weeks compared with before pacing (71 ± 2 vs. 27 ± 2%, p < 0.05) and mean pulmonary capillary wedge pressure (PCWP) was increased (8 ± 1 vs. 19 ± 3 mmHg). Famotidine ameliorated the decrease of LVEF and increase of PCWP, while the combination of carvedilol plus famotidine further improved both parameters compared with the carvedilol groups. These beneficial effects of famotidine were associated with a decrease of the myocardial cAMP level. Histamine H₂ receptor blockade preserves cardiac systolic function in dogs with pacing-induced heart failure, even in the presence of β-adrenergic receptor blockade. This finding strengthens the rationale for using histamine H₂ blockers in the treatment of heart failure.

Isoform-specific intermolecular disulfide bond formation of heterochromatin protein 1 (HP1)

Three mammalian isoforms of heterochromatin protein 1 (HP1), α, β, and γ, play diverse roles in gene regulation. Despite their structural similarity, the diverse functions of these isoforms imply that they are additionally regulated by post-translational modifications. Here, we have identified intermolecular disulfide bond formation of HP1 cysteines in an isoform-specific manner. Cysteine 133 in HP1α and cysteine 177 in HP1γ were involved in intermolecular homodimerization. Although both HP1α and HP1γ contain reactive cysteine residues, only HP1γ readily and reversibly formed disulfide homodimers under oxidative conditions. Oxidatively dimerized HP1γ strongly and transiently interacted with TIF1β, a universal transcriptional co-repressor. Under oxidative conditions, HP1γ dimerized and held TIF1β in a chromatin component and inhibited its repression ability. Our results highlight a novel, isoform-specific role for HP1 as a sensor of the cellular redox state.

Ablation of C/EBP homologous protein attenuates endoplasmic reticulum-mediated apoptosis and cardiac dysfunction induced by pressure overload

BACKGROUND

Apoptosis may contribute to the development of heart failure, but the role of apoptotic signaling initiated by the endoplasmic reticulum in this condition has not been well clarified.

METHODS AND RESULTS

In myocardial samples from patients with heart failure, quantitative real-time polymerase chain reaction revealed an increase in messenger RNA for C/EBP homologous protein (CHOP), a transcriptional factor that mediates endoplasmic reticulum-initiated apoptotic cell death. We performed transverse aortic constriction or sham operation on wild-type (WT) and CHOP-deficient mice. The CHOP-deficient mice showed less cardiac hypertrophy, fibrosis, and cardiac dysfunction compared with WT mice at 4 weeks after transverse aortic constriction, although the contractility of isolated cardiomyocytes from CHOP-deficient mice was not significantly different from that in the WT mice. In the hearts of CHOP-deficient mice, phosphorylation of eukaryotic translation initiation factor 2alpha, which may reduce protein translation, was enhanced compared with WT mice. In the hearts of WT mice, CHOP-increased apoptotic cell death with activation of caspase-3 was observed at 4 weeks after transverse aortic constriction. In contrast, CHOP-deficient mice had less apoptotic cell death and lower caspase-3 activation at 4 weeks after transverse aortic constriction. Furthermore, the Bcl2/Bax ratio was decreased in WT mice, whereas this change was significantly blunted in CHOP-deficient mice. Real-time polymerase chain reaction microarray analysis revealed that CHOP could regulate several Bcl2 family members in failing hearts.

CONCLUSIONS

We propose the novel concept that CHOP, which may modify protein translation and mediate endoplasmic reticulum-initiated apoptotic cell death, contributes to development of cardiac hypertrophy and failure induced by pressure overload.

X-box binding protein 1 regulates brain natriuretic peptide through a novel AP1/CRE-like element in cardiomyocytes

The unfolded protein response (UPR) is triggered to assist protein folding when endoplasmic reticulum (ER) function is impaired. Recent studies demonstrated that ER stress can also induce cell-specific genes. In this study, we examined whether X-box binding protein 1 (XBP1), a major UPR-linked transcriptional factor, regulates the expression of brain natriuretic peptide (BNP) in cardiomyocytes. In samples from failing human hearts, extensive splicing of XBP1 was observed along with increased expression of glucose-regulated protein of 78 kDa (GRP78), a target of spliced XBP1 (sXBP1), suggesting that the UPR was induced in heart failure in humans. Interestingly, quantitative real-time PCR revealed a positive correlation between cardiac expression of GRP78 and BNP, leading us to test the hypothesis that sXBP1 regulates BNP as well as GRP78 in cardiomyocytes. A pharmacological ER stressor caused a dose-dependent increase in the expression of sXBP1 and BNP by cultured cardiomyocytes. Short interfering RNA targeting XBP1 suppressed the induction of BNP expression by a pharmacological ER stressor or norepinephrine, which was rescued by the adenovirus-mediated overexpression of sXBP1. The promoter assay with overexpression of sXBP1 or norepinephrine showed that the proximal AP1/CRE-like element in the promoter region of BNP was critical for transcriptional regulation of BNP by sXBP1. Direct binding of sXBP1 to this element was confirmed by the chromatin immunoprecipitation assay. These findings suggest that ER stress observed in failing hearts regulates cardiac BNP expression through a novel promoter region of the AP1/CRE-like element.

Identification of genes related to heart failure using global gene expression profiling of human failing myocardium

Although various management methods have been developed for heart failure, it is necessary to investigate the diagnostic or therapeutic targets of heart failure. Accordingly, we have developed different approaches for managing heart failure by using conventional microarray analyses. We analyzed gene expression profiles of myocardial samples from 12 patients with heart failure and constructed datasets of heart failure-associated genes using clinical parameters such as pulmonary artery pressure (PAP) and ejection fraction (EF). From these 12 genes, we selected four genes with high expression levels in the heart, and examined their novelty by performing a literature-based search. In addition, we included four G-protein-coupled receptor (GPCR)-encoding genes, three enzyme-encoding genes, and one ion-channel protein-encoding gene to identify a drug target for heart failure using in silico microarray database. After the in vitro functional screening using adenovirus transfections of 12 genes into rat cardiomyocytes, we generated gene-targeting mice of five candidate genes, namely, MYLK3, GPR37L1, GPR35, MMP23, and NBC1. The results revealed that systolic blood pressure differed significantly between GPR35-KO and GPR35-WT mice as well as between GPR37L1-Tg and GPR37L1-KO mice. Further, the heart weight/body weight ratio between MYLK3-Tg and MYLK3-WT mice and between GPR37L1-Tg and GPR37L1-KO mice differed significantly. Hence, microarray analysis combined with clinical parameters can be an effective method to identify novel therapeutic targets for the prevention or management of heart failure.

The clock gene cryptochrome of Bactrocera cucurbitae (Diptera: Tephritidae) in strains with different mating times

Differences in mating time between populations can give rise to premating reproductive isolation. Tephritid fruit flies exhibit large variation in mating time among intra- or inter-specific populations. We previously cloned the clock gene period from two strains of melon fly, Bactrocera cucurbitae; in one the individuals mate early during the day, whereas in the other the individuals mate later. These strains were originally established by divergent artificial selection for developmental time, 'short' and 'long', with early and late mating times, respectively. The deduced amino acid sequences of PERIOD proteins for these two strains were reported to be identical. Here we cloned another clock gene cryptochrome (cry) from the two strains, and found two stable amino acid substitutions in the strains. In addition, the allele frequency at the two polymorphic sites of cry gene correlated with the circadian locomotor period (tau) across strains, whereas the expression pattern of cry mRNA in the heads of flies taken from the short strain significantly differed from that from the long strain. These findings suggest that variation in the cry gene is related to differences in the circadian behaviour in the two strains, thus implying that the cry gene may have an important role in reproductive isolation.

Interleukin-33 prevents apoptosis and improves survival after experimental myocardial infarction through ST2 signaling

BACKGROUND

ST2 is an interleukin (IL)-1 receptor family member with membrane-bound (ST2L) and soluble (sST2) isoforms, and sST2 is a biomarker for poor outcome in patients with myocardial infarction (MI). IL-33, the recently discovered ligand for ST2, activates nuclear factor kappaB and thus may regulate apoptotic cell death. We tested the hypothesis that IL-33 is cardioprotective after MI through ST2 signaling.

METHODS AND RESULTS

IL-33 protected cultured cardiomyocytes from hypoxia-induced apoptosis, and this cardioprotection was partially inhibited by sST2. IL-33 induced expression of the antiapoptotic factors XIAP, cIAP1, and survivin. To define the cardioprotective role of IL-33 in vivo, we performed a blinded and randomized study of ischemia/reperfusion in rats. IL-33 reduced cardiomyocyte apoptosis, suppressed caspase-3 activity, and increased expression of IAP family member proteins. IL-33 decreased both infarct and fibrosis volumes at 15 days; furthermore, both echocardiographic and hemodynamic studies revealed that IL-33 improved ventricular function. To determine whether cardioprotection by IL-33 is mediated through ST2 signaling, a randomized and blinded study of ST2(-/-) versus wild-type littermate mice was performed in 98 mice subjected to MI. At 4 weeks after MI, IL-33 reduced ventricular dilation and improved contractile function in wild-type mice but not in ST2(-/-) mice. Finally, IL-33 improved survival after MI in wild-type but not in ST2(-/-) mice.

CONCLUSIONS

IL-33 prevents cardiomyocyte apoptosis and improves cardiac function and survival after MI through ST2 signaling.