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result(s) for
"Yano, Masafumi"
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Enhancing calmodulin binding to ryanodine receptor is crucial to limit neuronal cell loss in Alzheimer disease
2021
Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by progressive neuronal cell loss. Recently, dysregulation of intracellular Ca
2+
homeostasis has been suggested as a common proximal cause of neural dysfunction in AD. Here, we investigated (1) the pathogenic role of destabilization of ryanodine receptor (RyR2) in endoplasmic reticulum (ER) upon development of AD phenotypes in
App
NL-G-F
mice, which harbor three familial AD mutations (Swedish, Beyreuther/Iberian, and Arctic), and (2) the therapeutic effect of enhanced calmodulin (CaM) binding to RyR2. In the neuronal cells from
App
NL-G-F
mice, CaM dissociation from RyR2 was associated with AD-related phenotypes, i.e. Aβ accumulation, TAU phosphorylation, ER stress, neuronal cell loss, and cognitive dysfunction. Surprisingly, either genetic (by V3599K substitution in RyR2) or pharmacological (by dantrolene) enhancement of CaM binding to RyR2 reversed almost completely the aforementioned AD-related phenotypes, except for Aβ accumulation. Thus, destabilization of RyR2 due to CaM dissociation is most likely an early and fundamental pathogenic mechanism involved in the development of AD. The discovery that neuronal cell loss can be fully prevented simply by stabilizing RyR2 sheds new light on the treatment of AD.
Journal Article
Enhancing calmodulin binding to cardiac ryanodine receptor completely inhibits pressure-overload induced hypertrophic signaling
2020
Cardiac hypertrophy is a well-known major risk factor for poor prognosis in patients with cardiovascular diseases. Dysregulation of intracellular Ca
2+
is involved in the pathogenesis of cardiac hypertrophy. However, the precise mechanism underlying cardiac hypertrophy remains elusive. Here, we investigate whether pressure-overload induced hypertrophy can be induced by destabilization of cardiac ryanodine receptor (RyR2) through calmodulin (CaM) dissociation and subsequent Ca
2+
leakage, and whether it can be genetically rescued by enhancing the binding affinity of CaM to RyR2. In the very initial phase of pressure-overload induced cardiac hypertrophy, when cardiac contractile function is preserved, reactive oxygen species (ROS)-mediated RyR2 destabilization already occurs in association with relaxation dysfunction. Further, stabilizing RyR2 by enhancing the binding affinity of CaM to RyR2 completely inhibits hypertrophic signaling and improves survival. Our study uncovers a critical missing link between RyR2 destabilization and cardiac hypertrophy.
Kohno, Kobayashi, Yamamoto et al. use a recent mouse model where the affinity of the cardiac ryanodine receptor (RyR2) to Calmodulin has been enhanced through a point mutation. They show that this mutation inhibits hypertrophic signaling and improves survival after pressure-induced overload, providing insights into the mechanisms of cardiac hypertrophy
Journal Article
Effects of pemafibrate on left ventricular diastolic function in patients with type 2 diabetes mellitus: a pilot study
by
Yamamoto, Takeshi
,
Akiyama, Masaru
,
Taguchi, Akihiko
in
Antidiabetics
,
Antihypertensives
,
Blood pressure
2023
Aims/introduction
Diabetic cardiomyopathy (DCM) is characterized predominantly by diastolic dysfunction. The multiple mechanisms underlying DCM include altered energy substrate utilization. Recent studies indicate that PPARα plays an important role in the pathogenesis of lipotoxic cardiomyopathy. Pemafibrate is known to be a selective PPARα modulator (SPPARMα). We thus investigated the effects of pemafibrate on cardiac diastolic function in patients with type 2 diabetes.
Materials and methods
Seventeen patients with type 2 diabetes (T2D) and hypertriglyceridemia were screened and treated with pemafibrate at a dose of 0.2 mg/day for 8–16 weeks. Fourteen patients were eligible for analysis. Echocardiography was used for assessment of diastolic function. Early diastolic filling velocity (E), late atrial filling velocity (A) and the E/A ratio were included in this study. Peak early diastolic annular velocities (e′) were also assessed using color tissue Doppler images. The primary endpoints were changes in the ratio of E to A (E/A), e’, and the ratio of E to e’ (E/e’) from baseline.
Results
Pemafibrate significantly increased average e’ (7.24 ± 0.58 vs 7.94 ± 0.67,
p
= 0.019) and a significant reduction in E/e’ (9.01 ± 0.94 vs 8.20 ± 0.91,
p
= 0.041). The increase in e’ was significantly related to increases in fasting blood glucose (
r
= 0.607,
p
= 0.021) and non-esterified fatty acid (
r
= 0.592,
p
= 0.026).
Conclusion
Pemafibrate improved diastolic function in patients with T2D and hypertriglyceridemia, suggesting that PPARα activation by pemafibrate prevents the development of DCM at an early stage.
Journal Article
Serial changes in the quantitative flow ratio in patients with intermediate residual stenosis after percutaneous coronary intervention
by
Okamura, Takayuki
,
Nakamura, Takeshi
,
Akase, Hideaki
in
Angina pectoris
,
Angiography
,
Angioplasty
2022
A beneficial surrogate marker for evaluating the effect of medical therapy is warranted to avoid deferred lesion revascularization. Similar to coronary artery imaging for monitoring the effects of medical therapy by analyzing plaque regression and stabilization, we hypothesized that evaluation of serial changes in the quantitative flow ratio (QFR) would serve as a surrogate marker of the effects of medical therapy against deferred lesion revascularization. Here, we investigated serial changes in QFR over time after percutaneous coronary intervention in patients who underwent medical therapy as a secondary prevention. Patients with intermediate stenosis in an untreated vessel observed at the baseline (BL) coronary angiography and follow-up (FU) coronary angiography performed 6–18 months after BL angiography were screened in 2 centers. A total of 52 patients were able to analyze both BL and FU QFR. The median QFR was 0.83 (IQR, 0.69, 0.89) at BL and 0.80 (IQR, 0.70, 0.86) at FU. The number of positive ΔQFR and negative ΔQFR were 21 and 31, respectively. The median ΔQFR was 0.05 (IQR, 0.03, 0.09) in positive ΔQFR and – 0.05 (IQR, – 0.07, – 0.03) in negative ΔQFR (
p
< 0.0001). Univariate and multivariate analyses revealed that LDL-C at FU predicted improvement in the QFR (OR 0.95, 95% confidence interval [0.91, 0.98],
P
= 0.001). Assessment of serial changes in the QFR may serve as a surrogate marker for the effects of medical therapy in patients with residual intermediate coronary stenosis.
Journal Article
The 1-minute sit-to-stand test to detect desaturation during 6-minute walk test in interstitial lung disease
2022
Although the 6 min walk test (6MWT) is well-established for assessing desaturation in patients with interstitial lung disease (ILD), it cannot be easily performed in primary healthcare settings. This retrospective observational study aimed to evaluate the usefulness of the 1 min sit-to-stand test (1STST) for assessing desaturation during 6MWT in ILD patients with normal resting blood oxygen levels. We included 116 patients, and the pulse oxygen saturation (SpO2) for both methods was analyzed. The SpO2 nadir during the 1STST and 6MWT correlated strongly (ρ = 0.82). The frequency of patients with nadir SpO2 < 90% was consistent for both tests (κ = 0.82). 1STST was superior to diffusing capacity for carbon monoxide in detecting desaturation during the 6MWT. These findings were similarly stratified according to performance status or dyspnea scale. The 1STST can easily measure exertional desaturation in ILD patients with normal resting blood oxygen levels and is an alternative to the 6MWT.
Journal Article
Factors limiting habitual exercise in patients with chronic heart failure: a multicenter prospective cohort study
by
Yamamoto, Takeshi
,
Kadokami, Toshiaki
,
Fukumoto, Yoshihiro
in
Aged
,
Aged, 80 and over
,
Biomedical Engineering and Bioengineering
2020
Physical activity (PA) in the daily life is strongly related to prognosis in patients with or at high risk of heart failure (HF). However, factors limiting habitual exercise and their prognostic impacts remain unknown in HF patients. We sent questionnaires asking factors limiting habitual exercise in the daily life to 8370 patients with Stage A/B/C/D HF in our nationwide registry and received valid responses from 4935 patients (mean age 71.8 years, 71.0% male). Among the 5 components consisting of “busyness”, “weak will”, “dislike, “socioeconomic reasons” and “diseases” in the questionnaires, “busyness” (34.5%) and “diseases” (34.7%) were the most frequently reported factors limiting habitual exercise, while “socioeconomic reasons” were the least (15.3%). Multiple Cox proportional hazard models indicated that “busyness”and “diseases” were associated with better (hazard ratio (HR) 0.53, 95% confidence interval (CI) 0.39–0.72,
P
< 0.001) and worse prognosis (HR 1.57, 95% CI 1.21–1.98,
P
< 0.001), respectively, while other components were not. Furthermore, it was noted that, while prognostic relevance of “busyness” limiting exercise did not differ by age or sex, negative impact of “diseases” was particularly evident in patients with age < 75 years (
P
for interaction < 0.01). Factors limiting habitual exercise were associated with “busyness” and “diseases”, but not with “weak will”, “dislike, or “socioeconomic reasons”. While “busyness” was associated with better prognosis regardless of age and sex, “diseases” was associated with worse prognosis in younger populations. Thus, physicians may pay more attentions to the reasons that limit exercise in the daily lives of HF patients rather than the low amount of exercise itself.
Journal Article
An impact of superior vena cava isolation in non‐paroxysmal atrial fibrillation patients with low voltage areas
2021
Background This study aimed to investigate the correlation between left atrial low‐voltage areas (LVAs) and an arrhythmogenic superior vena cava (SVC) and the impact on the efficacy of an empiric SVC isolation (SVCI) along with a pulmonary vein isolation (PVI) of non‐paroxysmal atrial fibrillation (non‐PAF) with or without LVAs. Methods We retrospectively enrolled 153 consecutive patients with non‐PAF who underwent a PVI alone (n = 51) or empiric PVI plus an SVCI (n = 102). Left atrial voltage maps were constructed during sinus rhythm to identify the LVAs (<0.5 mV). An arrhythmogenic SVC was defined as firing from the SVC and an SVC associated with the maintenance of AF‐like rapid SVC activity. Results An arrhythmogenic SVC and LVAs were identified in 28% and 65% of patients with a PVI alone and 36% and 73% of patients with a PVI plus SVCI, respectively (P = .275 and P = .353). In the multivariate analysis a female gender, higher pulmonary artery systolic pressure (PAPs), and arrhythmogenic SVC were associated with the presence of LVAs. In the PVI plus SVCI strategy, there was no significant difference in the atrial tachyarrhythmia/AF‐free survival between the patients with and without LVAs after initial and multiple sessions (50% vs. 61%; P = .386, 73% vs. 79%; P = .530), however, differences were observed in the PVI alone group (27% vs. 61%; P = .018, 49% vs. 78%; P = .046). Conclusions The presence of LVAs was associated with an arrhythmogenic SVC. An SVCI may have the potential to compensate for an impaired outcome after a PVI in non‐PAF patients with LVAs. The LVAs was associated with an arrhythmogenic SVC in non‐PAF patients. An SVCI compensated for an impaired outcome after PVI in non‐PAF patients with LVAs.
Journal Article
Medication persistence rates and predictive factors for discontinuation of antifibrotic agents in patients with idiopathic pulmonary fibrosis: a real-world observational study
by
Oishi, Keiji
,
Utsunomiya, Toshiaki
,
Sakamoto, Kenji
in
Aged
,
Disease Progression
,
Drug Administration Schedule
2019
Background:
In patients with idiopathic pulmonary fibrosis (IPF), continuing treatment with antifibrotic agents is crucial to decrease the reduction of forced vital capacity and mortality rate. However, predictive factors for the discontinuation of antifibrotic agents are unknown. This study aims to investigate the clinical characteristics and predictive factors for the discontinuation of antifibrotic agents in patients with IPF.
Methods:
This was a double-center retrospective study that enrolled patients with IPF treated with pirfenidone or nintedanib between 2009 and 2017. We compared clinical parameters between the medication-continuing group and the discontinued group. The predictive factors were determined using Cox proportional hazards analyses.
Results:
A total of 66 subjects were included: 43 received pirfenidone and 23 received nintedanib. At 1 year, 23 of 66 patients had discontinued due to adverse events (n = 12), disease progression (n = 9), or death (n = 2). The characteristics of the discontinuation group were poor performance status (PS) and delay from diagnosis to treatment. In the receiver operating characteristic (ROC) analysis associated with the discontinuation of antifibrotic agents, PS was the highest area under the ROC curve (AUC) value (cut-off value, 2; AUC, 0.83; specificity, 63%; sensitivity, 87%). This finding was consistent even when analyzing, except for examples of death and adjusting for the type of antifibrotic agent. The treatment persistence rate by PS was PS 0–1 = 90%, PS 2 = 65%, and PS 3 = 19%. Analysis of the relationship between PS and administration period of antifibrotic agents revealed that delays from diagnosis to treatment led to worsening of dyspnea, a decline in lung function, and deterioration of PS.
Conclusions:
PS may be informative for predicting discontinuation of medication. Our data reinforced the importance of early initiation of antifibrotic treatment, and we suggest PS should be used as a guide for starting antifibrotic agents in everyday practice.
The reviews of this paper are available via the supplementary material section.
Journal Article
Anti-neutrophil cytoplasmic antibody–associated vasculitis complicated with diffuse alveolar haemorrhage and central nervous system vasculitis
2021
Diffuse alveolar haemorrhage and central nervous system vasculitis are life-threatening complications of anti-neutrophil cytoplasmic antibody-associated vasculitis. The simultaneous occurrence of diffuse alveolar haemorrhage and central nervous system vasculitis is a rare presentation of antibody-associated vasculitis. Its diagnosis by histopathology is difficult because biopsy is difficult to perform, and urgent treatment is needed. We report a case of a Japanese man with diffuse alveolar haemorrhage and central nervous system vasculitis associated with antibody-associated vasculitis. New classification criteria may be needed for diffuse alveolar haemorrhage and central nervous system vasculitis associated with systemic vasculitis. When antibiotic-resistant atypical bilateral pneumonia is noted in the acute phase of a cerebral stroke, with elements suggestive of vasculitis, clinicians should be aware that diffuse alveolar haemorrhage and central nervous system vasculitis may occur simultaneously.
Journal Article