Myosin Light Chain Phosphatase Plays an Important Role in Cardiac Fibrosis in a Model of Mineralocorticoid Receptor-Associated Hypertension

BACKGROUND

Myosin phosphatase targeting subunit 2 (MYPT2) is an important subunit of cardiac MLC (myosin light chain) phosphatase, which plays a crucial role in regulating the phosphorylation of MLC to phospho-MLC (p-MLC). A recent study demonstrated mineralocorticoid receptor-related hypertension is associated with RhoA/Rho-associated kinase/MYPT1 signaling upregulation in smooth muscle cells. Our purpose is to investigate the effect of MYPT2 on cardiac function and fibrosis in mineralocorticoid receptor-related hypertension.

METHODS AND RESULTS

HL-1 murine cardiomyocytes were incubated with different concentrations or durations of aldosterone. After 24-hour stimulation, aldosterone increased CTGF (connective tissue growth factor) and MYPT2 and decreased p-MLC in a dose-dependent manner. MYPT2 knockdown decreased CTGF. Cardiac-specific MYPT2-knockout (c-MYPT2-/-) mice exhibited decreased type 1 phosphatase catalytic subunit β and increased p-MLC. A disease model of mouse was induced by subcutaneous aldosterone and 8% NaCl food for 4 weeks after uninephrectomy. Blood pressure elevation and left ventricular hypertrophy were observed in both c-MYPT2-/- and MYPT2+/+ mice, with no difference in heart weights or nuclear localization of mineralocorticoid receptor in cardiomyocytes. However, c-MYPT2-/- mice had higher ejection fraction and fractional shortening on echocardiography after aldosterone treatment. Histopathology revealed less fibrosis, reduced CTGF, and increased p-MLC in c-MYPT2-/- mice. Basal global radial strain and global longitudinal strain were higher in c-MYPT2-/- than in MYPT2+/+ mice. After aldosterone treatment, both global radial strain and global longitudinal strain remained higher in c-MYPT2-/- mice compared with MYPT2+/+ mice.

CONCLUSIONS

Cardiac-specific MYPT2 knockout leads to decreased myosin light chain phosphatase and increased p-MLC. MYPT2 deletion prevented cardiac fibrosis and dysfunction in a model of mineralocorticoid receptor-associated hypertension.

Management of pulmonary hemodynamics prior to delivery in a pregnant woman with development of decompensated pulmonary arterial hypertension

Prompt termination of pregnancy in patients with decompensated pulmonary arterial hypertension (PAH) is imperative for improvement of maternal hemodynamics, but such termination may also result in maternal death due to further deterioration of PAH immediately after delivery. However, there have been limited reports on whether implementation of PAH therapy with continuation of pregnancy improves the maternal outcome, especially in treatment-naïve patients with PAH. A 24-year-old woman was admitted to our hospital with a chief complaint of dyspnea (WHO functional class IV) at 22 weeks and 3 days of gestation. She was diagnosed with PAH accompanied by right heart failure and low cardiac output. Intensive treatment was initiated with inotropic agents, oxygen therapy, and PAH therapy, resulting in improvement of her hemodynamics. A caesarean section was performed at 23 weeks and 3 days. Although her pulmonary arterial pressure transiently increased with oxygenation deteriorating immediately after delivery, worsening PAH improved without mechanical circulatory support. She continued receiving pulmonary vasodilators without relapse of pulmonary hypertension for three years. The improvement of pulmonary hemodynamics prior to delivery with PAH therapy led to a favorable outcome after delivery.

Learning objective

Pulmonary hemodynamics in pregnant patients with pulmonary arterial hypertension (PAH) can deteriorate with the continuation of pregnancy, while termination can also cause PAH surge immediately after delivery. In treatment-naïve patients with PAH, who are most likely to benefit from PAH therapy, implementation of PAH therapy with continuation, even with a decompensated status, may improve the hemodynamics prior to delivery, resulting in a favorable outcome after delivery.

Aggregated chromosomes/chromatin transfer: a novel approach for mitochondrial replacement with minimal mitochondrial carryover: the implications of mouse experiments for human aggregated chromosome transfer

Nuclear transfer techniques, including spindle chromosome complex (SC) transfer and pronuclear transfer, have been employed to mitigate mitochondrial diseases. Nevertheless, the challenge of mitochondrial DNA (mtDNA) carryover remains unresolved. Previously, we introduced a method for aggregated chromosome (AC) transfer in human subjects, offering a potential solution. However, the subsequent rates of embryonic development have remained unexplored owing to legal limitations in Japan, and animal studies have been hindered by a lack of AC formation in other species. Building upon our success in generating ACs within mouse oocytes via utilization of the phosphodiesterase inhibitor 3-isobutyl 1-methylxanthine (IBMX), this study has established a mouse model for AC transfer. Subsequently, a comparative analysis of embryo development rates and mtDNA carryover between AC transfer and SC transfer was conducted. Additionally, the mitochondrial distribution around SC and AC structures was investigated, revealing that in oocytes at the metaphase II stage, the mitochondria exhibited a relatively concentrated arrangement around the spindle apparatus, while the distribution of mitochondria in AC-formed oocytes appeared to be independent of the AC position. The AC transfer approach produced a marked augmentation in rates of fertilization, embryo cleavage, and blastocyst formation, especially as compared to scenarios without AC transfer in IBMX-treated AC-formed oocytes. No significant disparities in fertilization and embryo development rates were observed between AC and SC transfers. However, relative real-time PCR analyses revealed that the mtDNA carryover for AC transfers was one-tenth and therefore significantly lower than that of SC transfers. This study successfully accomplished nuclear transfers with ACs in mouse oocytes, offering an insight into the potential of AC transfers as a solution to heteroplasmy-related challenges. These findings are promising in terms of future investigation with human oocytes, thus advancing AC transfer as an innovative approach in the field of human nuclear transfer methodology.

Bilateral Nephrectomy for Resistant Hypertension and Secondary Aldosteronism in a Hemodialysis Patient: A Case Report

A 42-year-old Japanese woman with end-stage renal failure due to hypertension presented with a systolic blood pressure of 160-200 mmHg despite treatment with 4 different antihypertensive agents. The plasma aldosterone concentration (PAC) and plasma renin activity (PRA) were elevated. Adrenal vein sampling suggested bilateral excessive aldosterone secretion, whereas adrenocortical scintigraphy showed right-dominant accumulation. Open bilateral nephrectomy and right adrenalectomy improved the systolic blood pressure, PAC, and PRA. A pathological examination revealed zona glomerulosa hyperplasia but not microaldosteronoma. This report shows that bilateral nephrectomy, not unilateral adrenalectomy, is a potentially effective treatment option for resistant hypertension with an elevated renin-angiotensin-aldosterone system in hemodialysis patients.

Associated factors and effects of comorbid atrial fibrillation in hypertensive patients due to primary aldosteronism

The incidence of atrial fibrillation (AF) and risk of cardiovascular events are reportedly higher in patients with primary aldosteronism (PA) than essential hypertension. However, associated factors of comorbid AF and cardiovascular events in PA patients after PA treatment remain unclear. This nationwide registration study included PA patients ≥20 years old. Incident cardiovascular events were observed with a mean follow-up of approximately 3 years. A total of 3654 patients with PA were included at the time of analysis. Prevalence of AF was 2.4%. PA patients with AF were older, more frequently male and had longer duration of hypertension than those without AF. No significant difference in basal plasma and adrenal venous aldosterone concentration, renin activity, potassium concentration, confirmatory tests of PA, laterality or surgery rate were seen between groups. Logistic regression analysis showed age, male sex, cardiothoracic ratio, past history of coronary artery disease and heart failure were independent factors associated with AF. PA patients with AF showed a higher frequency of cardiovascular events than those without AF (P < 0.001). Multivariate Cox analyses demonstrated AF in addition to older age, duration of hypertension, body mass index and chronic kidney disease as independent prognostic factors for cardiovascular events after PA treatment. Incidence of cardiovascular events were significantly lower in PA patients with AF than AF patients from the Fushimi registry during follow-up after adjusting age, sex and systolic blood pressure. Early diagnosis of PA may prevent AF and other cardiovascular events in PA patients by shortening the duration of hypertension and appropriate PA treatment.

A hyperaldosteronism subtypes predictive model using ensemble learning

This study aimed to develop a machine-learning algorithm to diagnose aldosterone-producing adenoma (APA) for predicting APA probabilities. A retrospective cross-sectional analysis of the Japan Rare/Intractable Adrenal Diseases Study dataset was performed using the nationwide PA registry in Japan comprised of 41 centers. Patients treated between January 2006 and December 2019 were included. Forty-six features at screening and 13 features at confirmatory test were used for model development to calculate APA probability. Seven machine-learning programs were combined to develop the ensemble-learning model (ELM), which was externally validated. The strongest predictive factors for APA were serum potassium (s-K) at first visit, s-K after medication, plasma aldosterone concentration, aldosterone-to-renin ratio, and potassium supplementation dose. The average performance of the screening model had an AUC of 0.899; the confirmatory test model had an AUC of 0.913. In the external validation, the AUC was 0.964 in the screening model using an APA probability of 0.17. The clinical findings at screening predicted the diagnosis of APA with high accuracy. This novel algorithm can support the PA practice in primary care settings and prevent potentially curable APA patients from falling outside the PA diagnostic flowchart.

Moyamoya Disease Complicating Ebstein's Anomaly

Ebstein's anomaly is an uncommon congenital disorder affecting the tricuspid valve. We herein report a 38-year-old woman who experienced consciousness and sensory disturbance during treatment for heart failure caused by Ebstein's anomaly. Urgent magnetic resonance imaging and cerebral angiography demonstrated acute cerebral infarction and internal carotid artery obstruction with the development of collateral arteries. We diagnosed her with multiple cerebral infarctions due to moyamoya disease. Ebstein's anomaly concomitant with moyamoya disease is extremely rare. However, we should consider the possibility of this rare but important concurrence when treating patients with heart failure due to Ebstein's anomaly to avoid excessive diuresis and vasodilation and irreversible brain injury.

A Perihilar Variant of Focal Segmental Glomerulosclerosis Due to De novo Branchio-oto-renal Syndrome

Branchio-oto-renal syndrome is an autosomal dominant disorder characterized by branchial anomalies, hearing loss, and renal urinary tract malformations. We herein report a 32-year-old Japanese man with a right preauricular pit, bilateral mixed hearing loss, and malposition of the right kidney who presented with proteinuria. The findings of a left kidney biopsy were compatible with a perihilar variant of secondary focal segmental glomerular sclerosis. A trio exome analysis conducted among the patient and his parents failed to identify the causal gene variant, despite a sporadic pattern. His kidney function remained stable for 11 years with an angiotensin II receptor blocker.

Perinatal Hypoxia Aggravates Occlusive Pulmonary Vasculopathy In SU5416/Hypoxia-Treated Rats Later In Life

Pulmonary arterial hypertension (PAH) is a fatal disease, which is characterized by occlusive pulmonary vascular disease (PVD) in small pulmonary arteries. It remains unknown whether perinatal insults aggravate occlusive PVD later in life. We tested the hypothesis that perinatal hypoxia aggravates PVD and survival in rats. PVD was induced in rats with/without perinatal hypoxia (E14 to P3) by injecting SU5416 at 7 weeks of age and subsequent exposure to hypoxia for 3 weeks (SU5416/hypoxia). Hemodynamic and morphological analyses were performed in rats with/without perinatal hypoxia at 7 weeks of age (baseline rats, n=12) and at 15 weeks of age in 4 groups of rats: SU5416/hypoxia or control rats with/without perinatal hypoxia (n=40). Pulmonary artery smooth muscle cells (PASMCs) from the baseline rats with/without perinatal hypoxia were used to assess cell proliferation, inflammation and genomic DNA methylation profile. Although perinatal hypoxia alone did not affect survival, physiological or pathological parameters at baseline or at the end of the experimental period in controls, perinatal hypoxia decreased weight gain and survival rate, and increased right ventricular systolic pressure, right ventricular hypertrophy, and indices of PVD in SU5416/hypoxia rats. Perinatal hypoxia alone accelerated the proliferation and inflammation of cultured PASMCs from baseline rats, which was associated with DNA methylation. In conclusion, we established the first fatal animal model of PAH with worsening hemodynamics and occlusive PVD elicited by perinatal hypoxia, which was associated with hyperproliferative, pro-inflammatory, and epigenetic changes in cultured PASMCs. These findings provide insights into the treatment and prevention of occlusive PVD.

CRISPR-mediated Bmpr2 point mutation exacerbates late pulmonary vasculopathy and reduces survival in rats with experimental pulmonary hypertension

Background

Patients with pulmonary arterial hypertension (PAH) carrying bone morphogenetic protein receptor type 2 (Bmpr2) mutations present earlier with severe hemodynamic compromise and have poorer survival outcomes than those without mutation. The mechanism underlying the worsening clinical phenotype of PAH with Bmpr2 mutations has been largely unaddressed in rat models of pulmonary hypertension (PH) because of the difficulty in reproducing progressive PH in mice and genetic modification in rats. We tested whether a clinically-relevant Bmpr2 mutation affects the progressive features of monocrotaline (MCT) induced-PH in rats.

Methods

A monoallelic single nucleotide insertion in exon 1 of Bmpr2 (+/44insG) was generated in rats using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9, then PH, pulmonary vascular disease (PVD) and survival after MCT injection with or without a phosphodiesterase type 5 inhibitor, tadalafil, administration were assessed.

Results

The +/44insG rats had reduced BMPR2 signalling in the lungs compared with wild-type. PH and PVD assessed at 3-weeks after MCT injection were similar in wild-type and +/44insG rats. However, survival at 4-weeks after MCT injection was significantly reduced in +/44insG rats. Among the rats surviving at 4-weeks after MCT administration, +/44insG rats had increased weight ratio of right ventricle to left ventricle plus septum (RV/[LV + S]) and % medial wall thickness (MWT) in pulmonary arteries (PAs). Immunohistochemical analysis showed increased vessels with Ki67-positive cells in the lungs, decreased mature and increased immature smooth muscle cell phenotype markers in the PAs in +/44insG rats compared with wild-type at 3-weeks after MCT injection. Contraction of PA in response to prostaglandin-F2α and endothelin-1 were significantly reduced in the +/44insG rats. The +/44insG rats that had received tadalafil had a worse survival with a significant increase in RV/(LV + S), %MWT in distal PAs and RV myocardial fibrosis compared with wild-type.

Conclusions

The present study demonstrates that the Bmpr2 mutation promotes dedifferentiation of PA smooth muscle cells, late PVD and RV myocardial fibrosis and adversely impacts both the natural and post-treatment courses of MCT-PH in rats with significant effects only in the late stages and warrants preclinical studies using this new genetic model to optimize treatment outcomes of heritable PAH.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02005-w.

Serum-Induced Expression of Brain Natriuretic Peptide Contributes to Its Increase in Patients with HFpEF

Brain natriuretic peptide (BNP) levels are increased in both patients with heart failure with preserved (HFpEF) and reduced ejection fraction (HFrEF), but the reasons for this remain unclear. Our purpose was to examine whether serum-induced BNP (iBNP) expression partly contributes to increased BNP in patients with HFpEF. BNP reporter cardiomyocytes from pBNP-luc-KI mice were stimulated with serum from patients with HFpEF or HFrEF (n = 114 and n = 82, respectively). Luciferase activity was examined as iBNP and the iBNP-to-BNP ratio was evaluated. Patient characteristics and clinical parameters were compared, and multivariate regression analysis was performed to determine independent predictors of the iBNP-to-BNP ratio. Female sex and frequencies of atrial fibrillation, hypertension and the use of a calcium channel blocker (CCB) were higher in HFpEF. The iBNP-to-BNP ratio was significantly higher in HFpEF (26.9) than in HFrEF (16.1, p < 0.001). Multivariate regression analysis identified the existence of HFpEF as an independent predictor of the iBNP-to-BNP ratio after adjusting for all other measurements (β = 0.154, p = 0.032). Age, hemoglobin, CCB usage and deceleration time were also independent predictors (β = 0.167, p = 0.025; β = 0.203, p = 0.006; β = 0.138, p = 0.049; and β = 0.143, p = 0.049, respectively). These results indicate that the elevated BNP in patients with HFpEF is partly due to iBNP from the heart.

Endovascular Treatment for Lower-extremity Arterial Thrombosis in a Patient with Congenital Afibrinogenemia and a History of Bleeding Complications

Congenital afibrinogenemia is a rare autosomal recessive blood disorder that accompanies thrombotic complications and is associated with bleeding tendency. The management of these opposing complications remains a challenge. Endovascular treatment (EVT) for peripheral arterial thrombosis has not been described in previous studies. A 57-year-old man with congenital afibrinogenemia developed back pain and left lower leg pain. The cause of the pain was confirmed to be renal infarction and lower extremity arterial thrombosis by Doppler ultrasound and contrast-enhanced computed tomography. He was treated with EVT for the lower extremity arterial thrombosis, leading to an excellent short-term improvement without bleeding.

Renocardiac protective effects of SGLT2 inhibitor combined with angiotensin receptor blocker in salt sensitive Dahl rats

Background

Kidney plays a central role in regulating salt-sensitivity of blood pressure (BP) to governs sodium excretion via several mechanisms including pressure natriuresis and the actions of renal sodium transporters.

Purpose

We clarified the effects of combination treatment of sodium-glucose cotransporter 2 (SGLT2) inhibitor and angiotensin receptor blocker (ARB) on BP and the pathogenesis of renocardiac injuries, and elucidated underlying molecular mechanisms involved in the regulation of renal sodium handling in the development of salt-sensitivity by comparing with each monotreatment in Dahl salt-sensitive (DSS) hypertensive rats.

Methods

DSS rats were treated orally for 8-weeks with normal salt diet (0.3% NaCl) (NS/Cont group), high salt diet (8% NaCl) (HS/Cont group), high salt diet with ipragliflozin (0.04%) (HS/Ipra group), high salt diet with losartan (0.05%) (HS/Los group), or high salt diet with combination of ipragliflozin and losartan (HS/Ipra+Los group).

Results

The combination group significantly reduced systolic BP compared with either high salt diet control group, losartan or ipragliflozin monotreatment groups (HS/Ipra+Los: 182.5±18.4mmHg vs HS/Cont: 227.7±26.1; HS/Ipra: 216.6±26.9; HS/Los: 208.6±21.6, at 8-weeks of treatment, P&lt;0.05, respectively) (Figure 1A). The slope of pressure-natriuresis curve was significantly increased in the HS/Ipra+Los group compared to that in the HS/Cont group (interaction P=0.024), HS/Ipra group (P=0.009), and HS/Los group (P=0.084) using the linear regression model (Figure 1B), which indicated that only the combination treatment of ipragliflozin and losartan improved salt-sensitivity. The combined treatment significantly improved creatinine clearance (HS/Ipra+Los: 3.3±0.9mL/min vs HS/Cont: 1.1±0.5; HS/Ipra: 1.7±0.6; HS/Los: 1.9±0.8, P&lt;0.05, respectively). The combination treatment also significantly ameliorated glomerulosclerosis, and improved cardiomyocyte hypertrophy and perivascular fibrosis (Figure 1C). Angiotensin II type 1 receptor (AT1R) protein expression level in the kidney was remarkably suppressed in the combination treatment group compared to the other high salt diet groups. The protein expression level of Na+/H+ exchanger isoform 3 (NHE3) and Na+-K+-Cl– cotransporter 2 (NKCC2), two of major sodium transports in the renal tubules, were significantly decreased with losartan monotreatment and combination treatment, but not with ipragliflozin monotreatment (Figure 2).

Conclusions

The dual inhibition of SGLT2 and AT1R effectively improved salt-sensitivity via reducing renal expression levels of the sodium transporters, which eventually lead to renocardiac protection. Thus, the combination treatment could be a novel and useful therapeutic strategy for treating salt-sensitive hypertension and renal injury in non-diabetic patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Grant-in-Aid for Scientific Research

Fatal myopericarditis complicated with coronary vein perforation under the triple antithrombotic therapy: a case report

Background 

Acute pericarditis generally follows a mild clinical course and is rarely fatal. Coronary vein involvement is rarely reported.

Case summary 

We report an autopsy case of cardiac tamponade from idiopathic myopericarditis due to coronary venous perforation under the triple antithrombotic therapy. A 69-year-old man was admitted to our hospital with abnormal findings on electrocardiography, bloody pericardial effusion, and mild elevation of troponin I. Oral anti-inflammatories were started and the patient followed a benign course. However, on hospital Day 5, he suddenly suffered cardiogenic shock with pulseless electric activity due to cardiac tamponade under the combination use of the dual antiplatelet drugs and an anticoagulant drug. He died despite intense medical treatment. Autopsy revealed cardiac tamponade caused by perforation in the coronary venous wall. To the best of our knowledge, this is the first description of fatal myopericarditis as a complication of coronary venous perforation.

Discussion 

The aetiology and mechanism remain unknown; however, we should take care for this rare complication in patients with acute myopericarditis and bloody effusion under the triple antithrombotic therapy.

Giant deep vein thrombus complicating endovascular cooling therapy after cardiac arrest in a boy with hypertrophic cardiomyopathy

Mild hypothermia therapy (33-36 °C) is useful in preventing anoxic brain injury occurring after return of spontaneous circulation among survivors of cardiac arrest. Adverse events generally include bleeding, pneumonia, bradycardia, and deep vein thrombosis (DVT). However, one rare complication is huge DVT. We recently encountered a boy with ventricular fibrillation due to hypertrophic cardiomyopathy complicated by huge DVT from bilateral common femoral veins close to the hepatic vein during endovascular cooling therapy via his femoral vein. We successfully managed this case without any complications after infusion of unfractionated heparin to maintain a relatively high activated partial thromboplastin time. <Learning objective: We should be more careful in screening for deep vein thrombosis before and after endovascular cooling therapy.>.

Generation of Transgenic Mice that Conditionally Overexpress Tenascin-C

Tenascin-C (TNC) is an extracellular matrix glycoprotein that is expressed during embryogenesis. It is not expressed in normal adults, but is up-regulated under pathological conditions. Although TNC knockout mice do not show a distinct phenotype, analyses of disease models using TNC knockout mice combined with in vitro experiments revealed the diverse functions of TNC. Since high TNC levels often predict a poor prognosis in various clinical settings, we developed a transgenic mouse that overexpresses TNC through Cre recombinase-mediated activation. Genomic walking showed that the transgene was integrated into and truncated the Atp8a2 gene. While homozygous transgenic mice showed a severe neurological phenotype, heterozygous mice were viable, fertile, and did not exhibit any distinct abnormalities. Breeding hemizygous mice with Nkx2.5 promoter-Cre or α-myosin heavy chain promoter Cre mice induced the heart-specific overexpression of TNC in embryos and adults. TNC-overexpressing mouse hearts did not have distinct histological or functional abnormalities. However, the expression of proinflammatory cytokines/chemokines was significantly up-regulated and mortality rates during the acute stage after myocardial infarction were significantly higher than those of the controls. Our novel transgenic mouse may be applied to investigations on the role of TNC overexpression in vivo in various tissue/organ pathologies using different Cre donors.

Baseline clinical features in a large-scale registration survey of patient with hypertrophic cardiomyopathy throughout Japan: J-HCM registry study

Background

Hypertrophic cardiomyopathy (HCM) is a most prevalent primary myocardial disorder with heterogeneous clinical features. However, there have been few studies on clinical features of HCM as a prospective cohort. In 2015, we established a large-scale registration survey of patients with HCM throughout Japan, named J-HCM registry study.

Purpose

The aim of this study was to clarify the clinical features of Japanese patients with HCM.

Methods

J-HCM registry study is a prospective, multicenter investigation, consisting of 24 hospitals. This time, we present the baseline clinical characteristics in this survey.

Results

Total 1484 patients were registered. The ages at registration and at diagnosis were 65±15 and 56±17 years, respectively, and 806 patients (54%) were men. Majority of the patients (95%) was NYHA class I or II. With regard to subtypes of HCM, there were 526 patients (36%) in the HCM with left ventricular (LV) outflow tract obstruction, 126 patients (8%) in the mid-ventricular obstruction, 57 patients (4%) in the end-stage phase characterized by LV ejection fraction &lt;50%, and 197 patients (14%) in apical HCM. At registration, 80 patients (6%) had prior successful recovery from sustained ventricular tachycardia or ventricular fibrillation, 162 patients (11%) suffered from heart failure hospitalization, and 64 patients (4%) had history of embolic event. Regarding invasive treatment, 160 patients (10%) had prior septal reduction therapy and 162 patients (11%) had ICD implantation. According to the 2014 European Society of Cardiology Guidelines on sudden cardiac death (SCD) prevention, the study patients were divided into 3 categories by the HCM Risk-SCD calculator: patients distribution, 4% in the high risk group (≥6% calculated HCM Risk-SCD at 5 years), 7% in the intermediate risk group (4% to &lt;6%), 69% in the low risk group (&lt;4%), and 16% in the patients with extreme characteristics (Figure 1).

Conclusions

In this multicenter registration survey of patients with HCM, the baseline clinical characteristics were almost similar to several retrospective large-scale cohorts in Western countries except older age and less symptomatic state. This study will provide important knowledge regarding management of HCM.

Figure 1

Funding Acknowledgement

Type of funding source: None

Quantification of extracellular volume fraction by cardiac computed tomography for noninvasive assessment of myocardial fibrosis in hemodialysis patients

Extent of myocardial fibrosis in hemodialysis patients has been associated with poor prognosis. Myocardial extracellular volume (ECV) quantification using contrast enhanced cardiac computed tomography (CT) is a novel method to determine extent of myocardial fibrosis. Cardiac CT-based myocardial ECV in hemodialysis patients with those of propensity-matched non-hemodialysis control subjects were compared. Twenty hemodialysis patients (mean age, 67.4 ± 9.6 years; 80% male) and 20 propensity-matched non-hemodialysis controls (mean age, 66.3 ± 9.1 years; 85% male) who underwent comprehensive cardiac CT consisted of calcium scoring, coronary CT angiography, stress perfusion CT and delayed enhancement CT were evaluated. Myocardial ECV was significantly greater in the hemodialysis group than in the control group (33.8 ± 4.7% versus 26.6 ± 2.9%; P < 0.0001). In the hemodialysis group, modest correlation was evident between myocardial ECV and left atrial volume index (r = 0.54; P = 0.01), while there was no correlation between myocardial ECV and other cardiac parameters including left ventricular mass index and severity of myocardial ischemia. Cardiac CT-based myocardial ECV may offer a potential imaging biomarker for myocardial fibrosis in HD patients.

Obesity predicts persistence of resistant hypertension after surgery in patients with primary aldosteronism

OBJECTIVE

Primary aldosteronism (PA) is considered a major cause of resistant hypertension (RHT). The prevalence of RHT has been recently reported to reach 18% in general hypertension. However, little is known about the prevalence and the outcomes after adrenalectomy of RHT in PA. Therefore, we aimed to clarify the prevalence and surgical outcomes in patients with both PA and RHT.

PATIENTS AND DESIGN

Among 550 patients who underwent adrenalectomy for unilateral PA in the Japan PA Study, RHT was defined as an uncontrolled blood pressure (≥140/90 mm Hg) despite treatment with at least any three antihypertensives or hypertension controlled with at least four drugs. Surgical outcome was assessed by the biochemical and clinical outcome.

RESULTS

Although 40 (7.3%) patients fulfilled the criteria for preoperative RHT, this should be underestimated because only 36% of patients with postoperative RHT were classified as having preoperative RHT. The prevalence of preoperative RHT was approximately 20% when estimated using the total number of patients with postoperative RHT and the ratio of postoperative RHT in patients with preoperative RHT. Although an improvement in hypertension was achieved in approximately 80% of patients with preoperative RHT, 20% of these exhibited persistent RHT. These patients were more obese than those for whom RHT improved after surgery. Notably, body mass index of ≥25 kg/m² was an independent predictor of postoperative RHT.

CONCLUSIONS

The prevalence of RHT in PA was lower than expected even with the adjustment for underestimation. Furthermore, obesity is an independent factor predicting the postoperative persistence of RHT.

A study on the educational significance of special needs education in basis PHN education - 1st report

Background

For public health nurses to support school-aged children with disabilities who live in the community, it is necessary to understand the mechanism of special needs education and learn the inter-professional collaboration that takes place in it. A survey was conducted on school teachers supporting school-aged children with special needs, and the perception of educational significance in basic PHN education and its related factors were examined.

Methods

In December 2019, a survey questionnaire was sent to all 1,052 special needs schools in Japan. Of the 350 respondents, 330 valid replies were analyzed. Regarding the significance of providing special needs education in basic PHN education, we asked for answers on a four-point scale from “strongly agree” to “strongly disagree” and scored 4 to 1 points. Then, unpaired t-tests were performed between every two groups of “school-targeted type of disabilities,” “respondent's position,” and “respondent's perception/experience.” In addition, Pearson's correlation coefficient test was performed on the relationship with the years of teacher experience in special needs schools.

Results

Perception of the significance of providing education was as follows: “school-targeted type of disabilities” refers to school groups with hearing impairments (p &lt; 0.05), “respondent's position” groups are special needs education coordinators (p &lt; 0.05), “respondent's perception/experience” was significantly higher in the group with a high cognition of PHN work (p &lt; 0.05) and in the group with experience of cooperating with PHN (p &lt; 0.001). However, there was no significant correlation with the years of teacher experience in special needs schools.

Conclusions

There was a high perception of the significance of providing education in school groups with hearing impairment and groups with actual coordination experience, especially where early detection and care were particularly required, regardless of years of teacher experience.

Key messages

Special needs education should be included in basic PHN education to promote inter-professional collaboration for improving QOL of school-age children with disabilities living in communities. To foster the foundation for promoting special needs education in basic PHN education, in-service PHNs need to work closely with schools to meet their expectations for PHNs.

Teriparatide improves microarchitectural characteristics of peri-implant bone in orchiectomized rats

This study evaluated the peri-implant bone repair in orchiectomized rats receiving intermittently PTH 1-34. The treatment returned the bone quality and quantity of the animals to normal in the computerized microtomography, laser confocal microscopy, and histological analysis. The PTH 1-34 promoted marked bone formation with increased volume, improved quality, and greater bone turnover.

INTRODUCTION

Osteoporosis can be a problem in implant osseointegration. So this study aimed to evaluate the quantity and quality of peri-implant bone repair in orchiectomized Wistar rats receiving intermittently administered PTH 1-34.

METHODS

Animals (n = 24) were divided into 3 groups: healthy control (SHAM), orchiectomized (ORQ), and orchiectomized and treated with 0.5 μg/kg/day PTH 1-34 (TERI), and each received an implant in the right and left tibial metaphysis, which was allowed to repair for 60 days. The resultant bone formation was evaluated through computerized microtomography (micro-CT) to compare the percent bone volume (BV/TV), trabecular thickness (Tb.Th), trabecular number and separation (Tb.N, Tb.Sp), and bone implant contact (BIC) through the intersection surface (i.S) between groups. Laser confocal microscopy was used to evaluate fluorochrome areas for mineral apposition rate (MAR) and neoformed bone area (NBA). In addition, histological evaluation of calcified tissues with Stevenel blue and alizarin red staining was performed.

RESULTS

Treatment with PTH 1-34 returned the bone quality and quantity of the osteoporotic animal to normal, as the TERI group presented statistically significant higher values for BV/TV, Tb.Th, and BIC parameters compared with ORQ (p < 0.05), but when compared with SHAM (p > 0.05), no statistical difference was noted. In addition, in the bone turnover analysis (MAR, NBA) for TERI, the highest results are presented, followed by SHAM, and then ORQ (TERI × ORQ: p < 0.05).

CONCLUSIONS

Intermittent treatment with PTH 1-34 on orchiectomized animals promoted marked bone formation with increased volume, improved quality, and greater bone turnover in the peri-implant space, returning the bone quality and quantity to the present standard in healthy animals.

Diabetes Mellitus Itself Increases Cardio-Cerebrovascular Risk and Renal Complications in Primary Aldosteronism

CONTEXT

The prevalence of diabetes mellitus (DM) in patients with primary aldosteronism (PA) is higher than in those with essential hypertension and the general population. Although DM is a common major risk factor for cardio-cerebrovascular (CCV) diseases and renal complications, details of its effects in PA have not been demonstrated.

OBJECTIVE

The aim of this study was to determine the effects of coexistent DM on the risk of CCV events and progression of renal complications in PA patients.

DESIGN

A multi-institutional, cross-sectional study was conducted.

PATIENTS AND METHODS

PA patients experienced between January 2006 and October 2016 and with available data of CCV events and DM were enrolled from the Japan PA registry of the Japan Primary Aldosteronism Study/Japan Rare Intractable Adrenal Diseases Study (n = 2524). CCV events and renal complications were compared between a DM group and a non-DM group by logistic and liner-regression analysis.

RESULTS

DM significantly increased the odds ratio (OR) of CCV events (OR 1.59, 95% CI: 1.05-2.41) and that of proteinuria (OR 2.25, 95% CI: 1.59-3.16). DM correlated significantly with declines in estimated glomerular filtration rate (β = .05, P = .02).

CONCLUSIONS

This the first report to demonstrate the presence of DM as an independent risk factor for CCV events and renal complications, even in PA patients. Management of DM should be considered in addition to the specific treatment of PA.

Associations Between Changes in Plasma Renin Activity and Aldosterone Concentrations and Changes in Kidney Function After Treatment for Primary Aldosteronism

Introduction

Greater reduction in estimated glomerular filtration rate (eGFR) after specific treatment for primary aldosteronism (PA) reflects improvement in glomerular hyperfiltration associated with PA and leads to better patient outcomes. However, little is known regarding the mechanisms underlying eGFR reduction after treatment for PA.

Methods

We analyzed data from the nationwide PA registry in Japan. Patients were assigned to adrenalectomy (n = 438) and mineralocorticoid receptor (MR) antagonist (n = 746) groups. We assessed associations between changes in blood pressure (BP), plasma renin activity (PRA) and plasma aldosterone concentrations (PAC), and eGFR before and 6 months after treatment for both groups.

Results

In a multivariable linear regression, the adjusted β values (95% confidence interval [CI]) for change in eGFR after treatment were −2.76 (−4.29, −1.22) ml/min per 1.73 m² for PRA (per 3.2 ng/ml per hour), and 1.97 (1.08, 2.85) ml/min per 1.73 m² for PAC (per 236.1 pg/ml) in the adrenalectomy group; and −0.45 (−0.89, −0.01) ml/min per 1.73 m² for PRA and −0.72 (−1.62, 0.18) ml/min per 1.73 m² for PAC in the MR antagonist group. Change in mean arterial pressure after treatment was not significantly associated with change in eGFR in either group. Changes in PRA and PAC but not BP before and 6 months after treatment for PA were associated with greater reductions in eGFR.

Conclusion

Post-treatment improvements in glomerular hyperfiltration may be attributable to decreased MR activity in the kidneys, but not to reductions in systemic BP.

Nadir Aldosterone Levels After Confirmatory Tests Are Correlated With Left Ventricular Hypertrophy in Primary Aldosteronism

Left ventricular hypertrophy (LVH) is often seen in patients with primary aldosteronism (PA), and the prevalence of LVH is reportedly higher among patients with PA than patients with essential hypertension. However, the correlation between aldosterone levels and LVH is undefined, and how aldosterone affects LVH in patients with PA remains unclear. We, therefore, retrospectively assessed a large PA database established by the multicenter JPAS (Japan Primary Aldosteronism Study) to reveal the factors associated with LVH in patients with PA without suspected autonomous cortisol secretion. In the 1186 patients with PA studied, the basal plasma aldosterone concentration, plasma renin activity, and the aldosterone-to-renin ratio did not significantly correlate with left ventricular LV mass index (LVMI) in single or multiple regression analyses. However, the plasma aldosterone concentration after the captopril challenge test or saline-infusion test, which are associated with autonomous aldosterone secretion, correlated significantly with LVMI, even after adjusting for patients’ backgrounds, including age and blood pressure. In addition, hypokalemia and the unilateral subtype also correlated with LVMI. Longitudinal subanalysis of medically or surgically treated patients with PA showed significant reductions in LVMI in both the surgery (63.0±18.1 to 55.3±19.5 g/m 2.7 , P <0.001) and drug treatment (56.8±14.1 to 52.1±13.5 g/m 2.7 , P <0.001) groups. Our results suggest the autonomous aldosterone secretion level, not the basal aldosterone level itself, is relevant to LVH in patients with PA. In addition, the elevated LVMI seen in patients with PA is at least partially reversible with surgical or medical treatment.

Effect of cosyntropin during adrenal venous sampling on subtype of primary aldosteronism: analysis of surgical outcome

OBJECTIVES

We investigated the clinical significance of ACTH stimulation during adrenal venous sampling (AVS) by surgical outcome of primary aldosteronism (PA).

DESIGN

Multicenter retrospective study by Japan PA study.

METHOD

We allocated 314 patients with both basal and ACTH-stimulated AVS data who underwent adrenalectomy to three groups: basal lateralization index (LI) ≥2 with ACTH-stimulated LI ≥4 on the ipsilateral side (Unilateral (U) to U group, n = 245); basal LI <2 with ACTH-stimulated LI ≥4 (Bilateral (B) to U group, n = 15); and basal LI ≥2 with ACTH-stimulated LI <4 (U to B group, n = 54). We compared surgical outcomes among the groups using the Primary Aldosteronism Surgical Outcome (PASO) criteria.

RESULTS

Compared with U to U group, U to B group had poor clinical and biochemical outcomes and low rates of adrenal adenoma as pathological findings (P = 0.044, 0.006, and 0.048, respectively), although there were no significant differences between U to U and B to U groups. All patients in U to B group with clinical and biochemical benefits, however, had adrenal adenoma as pathological findings and could be well differentiated from those with poor surgical outcomes via basal LI (>8.3), but not ACTH-stimulated LI. These results were similar even when we defined each group based on a cut-off value of 4 for basal LI.

CONCLUSIONS

Although PA patients in U to B group had worse surgical outcomes than did those in U to U group, basal LI could discriminate among patients with better surgical outcomes in U to B group.

Basal Plasma Aldosterone Concentration Predicts Therapeutic Outcomes in Primary Aldosteronism

Purpose

Normal basal plasma aldosterone concentration (PAC) reflects mild aldosterone excess compared to high basal PAC. We previously reported lower risk for cardiovascular and cerebrovascular events in patients with primary aldosteronism (PA) and normal basal PAC (nPA) than in those with high basal PAC (hPA). However, the differences in therapeutic outcomes between nPA and hPA are unclear. The aim of this multi-institutional, retrospective cohort study was to determine the clinical significance of nPA to therapeutic outcomes, including adrenalectomy (ADX) and treatment with mineralocorticoid receptor antagonists (MRAs).

Methods

A total of 1146 patients with PA who were diagnosed and underwent adrenal venous sampling (AVS) between January 2006 and October 2016 were enrolled. The clinical parameters at baseline and after ADX or treatment with MRA were compared between the nPA and hPA groups.

Results

Significantly higher rates of absent clinical success (36.6 vs. 21.9%, P = 0.01) and absent biochemical success (26.4 vs. 5.2%, P < 0.01) were found for the nPA group than for the hPA group, respectively. Logistic regression analysis identified baseline PAC as a significant independent predictor of absent clinical success of ADX and MRAs.

Conclusions

Plasma aldosterone concentration at baseline was a significant and independent predictor of absent clinical success of ADX and MRA. Mineralocorticoid receptor antagonist treatment appeared to be a better therapeutic choice than ADX in the nPA group.

P5437The BNP reporter mouse by knock-in technology is useful for the analysis of mechanism in reactivation of BNP in adult heart

Background

It has been thought BNP is induced by undetermined stretch-activated receptors, however, which receptor is associated remains unknown. The stretch-activated receptors include mechanically gated channels, which can be activated by a mechanical stimulus alone, and mechanically modulated channels, which require nonmechanical stimuli such as agonists. It has been recently shown that 1.1kb segment of mouse NPPB promoter dose not reproduce the pattern of reactivation of BNP in adult heart, although it could monitor the expression of BNP in neonatal cardiomyocytes.

Purpose

Our aim is to develop a true BNP reporter mouse and examine whether this mouse is useful or not for the investigation of BNP reactivation mechanism in adult heart and for the measurement of serum-induced BNP expression in patients with heart failure.

Methods

We generated the BNP reporter mice by knocking luciferase cDNA in the initiation site of NPPB. In vivo imaging of luciferase was performed in the BNP reporter mice after the intraperitoneal injection of luciferin. The luciferase activity was examined in neonatal cardiomyocyte, isolated adult cardiomyocytes, adult cardiac dissected tissue with or without 120–150% stretch or angiotensin II stimulation. Left anterior descending (LAD) coronary artery was ligated to study myocardial infarction. Cardiac dissected tissue segments from the BNP reporter mouse were incubated for 8 hours with 20% serum from patients with or without heart failure and the luciferase activity was measured after homogenization.

Results

The in vivo imaging system showed the activity of BNP was high in 1 day-old neonates and the reactivation of BNP in the adult heart after LAD ligation could be monitored by the luciferase activity (figure). The treatment of Ang II could increase the activity of pBNP more than ten folds in heart tissue from adult mice. On the other hand, the 120–150% stretch did not show any effect on the activity of pBNP in this system. We could not observe any activation of pBNP in cultured neonatal or adult cardiomyocytes demonstrated by immunostain with antibodies against luciferase after 120–150% stretch. Interestingly, the luciferase activity was extensively higher in cultured heart tissue segments from the BNP reporter mice after the treatment of serum from patients with heart failure than without heart failure.

In vivo imaging of BNP reporter mice

Conclusion

These results indicate the BNP reporter mouse by knock-in technology is useful for the analysis of mechanism in reactivation of BNP in adult heart and the elevation of BNP in patients of heart failure partly due to the serum-derived induction of BNP from heart.

BNP as a Major Player in the Heart-Kidney Connection

Brain natriuretic peptide (BNP) is an important biomarker for patients with heart failure, hypertension and cardiac hypertrophy. Although it is known that BNP levels are relatively higher in patients with chronic kidney disease and no heart disease, the mechanism remains unknown. Here, we review the functions and the roles of BNP in the heart-kidney interaction. In addition, we discuss the relevant molecular mechanisms that suggest BNP is protective against chronic kidney diseases and heart failure, especially in terms of the counterparts of the renin-angiotensin-aldosterone system (RAAS). The renal medulla has been reported to express depressor substances. The extract of the papillary tips from kidneys may induce the expression and secretion of BNP from cardiomyocytes. A better understanding of these processes will help accelerate pharmacological treatments for heart-kidney disease.

Novel molecular mechanisms in the inhibition of adrenal aldosterone synthesis: Action of tolvaptan via vasopressin V2 receptor-independent pathway

BACKGROUND AND PURPOSE

We investigated the inhibitory effect and associated molecular mechanisms of tolvaptan on angiotensin II (AngII)-induced aldosterone production in vitro and in vivo.

EXPERIMENTAL APPROACH

In vitro, H295R human adrenocarcinoma cells were incubated with 1 μmol·L^-1 arginine vasopressin (AVP) or dDAVP, or tolvaptan (0.1, 1, and 3 μmol·L^-1 ) in the presence and absence of 100 nmol·L^-1 of AngII. In vivo, Sprague-Dawley rats were treated with tolvaptan 0.05% in the diet for 6 days in the presence and absence of 200 pmol·min^-1 AngII.

KEY RESULTS

Tolvaptan suppressed AngII-induced aldosterone production in a dose-dependent manner in H295R cells, whereas neither AVP nor dDAVP in the presence or absence of AngII altered aldosterone production, suggesting the vasopressin V₂ receptor was not involved in the inhibitory effect of tolvaptan on aldosterone synthesis. In addition, tolvaptan inhibited the AngII-induced increase in aldosterone synthase (CYP11B2) protein levels without suppressing CYP11B2 mRNA expression. Notably, tolvaptan increased the levels of unfolded protein response (UPR) marker DDIT3 and eIF2α phosphorylation (a UPR-induced event), which could block the translation of CYP11B2 mRNA into protein and thereby inhibit aldosterone production. In vivo, tolvaptan significantly inhibited AngII-induced increases in serum and adrenal aldosterone levels and CYP11B2 protein levels. This anti-aldosterone effect was associated with a reduction in the elevated systolic and diastolic BP.

CONCLUSIONS AND IMPLICATIONS

Tolvaptan inhibited AngII-stimulated aldosterone production via a V₂ receptor-independent pathway, which can counteract or even surpass its potential activating effect of diuresis-induced aldosterone secretion in certain aldosterone-mediated pathological conditions.