Human leukocyte antigen-DQ risk heterodimeric haplotypes of left ventricular dysfunction in cardiac sarcoidosis: an autoimmune view of its role.

Cardiac sarcoidosis (CS) is the scarring of heart muscles by autoimmunity, leading to heart abnormalities and patients with sarcoidosis with cardiac involvements have poor prognoses. Due to the small number of patients, it is difficult to stratify all patients of CS by human leukocyte antigen (HLA) analysis. We focused on the structure of antigen-recognizing pockets in heterodimeric HLA-class II, in addition to DNA sequences, and extracted high-affinity combinations of antigenic epitopes from candidate autoantigen proteins and HLA. Four HLA heterodimer-haplotypes (DQA1*05:03/05:05/05:06/05:08-DQB1*03:01) were identified in 10 of 68 cases. Nine of the 10 patients had low left ventricular ejection fraction (< 50%). Fourteen amino-acid sequences constituting four HLA anchor pockets encoded by the HLA haplotypes were all common, suggesting DQA1*05:0X-DQB1*03:01 exhibit one group of heterodimeric haplotypes. The heterodimeric haplotypes recognized eight epitopes from different proteins. Assuming that autoimmune mechanisms might be activated by molecular mimicry, we searched for bacterial species having peptide sequences homologous to the eight epitopes. Within the peptide epitopes form the SLC25A4 and DSG2, high-homology sequences were found in Cutibacterium acnes and Mycobacterium tuberculosis, respectively. In this study, we detected the risk heterodimeric haplotypes of ventricular dysfunction in CS by searching for high-affinity HLA-class II and antigenic epitopes from candidate cardiac proteins.

Efficacy of azilsartan on left ventricular diastolic dysfunction compared with candesartan: J-TASTE randomized controlled trial.

Characterized by ventricular and vascular stiffness, heart failure with preserved ejection fraction (HFpEF) has led to high morbidity and mortality. As azilsartan is an angiotensin receptor blocker with the highest myocardial and vascular affinities, azilsartan may improve the left ventricular (LV) diastolic function in patients with hypertension and either HFpEF or HF with mildly reduced ejection fraction (HFmrEF) more than candesartan. In this randomized, open-label trial, we randomly assigned 193 hypertensive patients with HF and LV ejection fraction ≥ 45% to 20 mg of azilsartan (n = 95) or 8 mg of candesartan (n = 98), once daily for 48 weeks. After the initiation of treatment, changes in the doses of the study drugs were permitted based on the patient's conditions, including blood pressure (median dose at 48 weeks: azilsartan 20.0 mg/day, candesartan 8.0 mg/day). The primary endpoint was the baseline-adjusted change in the ratio of peak early diastolic transmitral flow velocity (E) to early diastolic mitral annular velocity (e') (E/e'). Adjusted least-squares mean (LSM) change in E/e' was - 0.8 (95% confidence interval [CI] - 1.49 to - 0.04) in the azilsartan group and 0.2 (95% CI - 0.49 to 0.94) in the candesartan group, providing the LSM differences of - 1.0 (95% CI - 2.01 to 0.03, P = 0.057). The median change in left atrial volume index was - 2.7 mL/m2 with azilsartan vs 1.4 mL/m2 with candesartan (P = 0.091). The frequency of adverse events related to hypotension and hyperkalemia did not differ between the groups. The current study did not provide strong evidence that azilsartan improves LV diastolic dysfunction, and further confirmatory study is required.

Restoration of Cardiac Myosin Light Chain Kinase Ameliorates Systolic Dysfunction by Reducing Superrelaxed Myosin.

BACKGROUND: Cardiac-specific myosin light chain kinase (cMLCK), encoded by MYLK3, regulates cardiac contractility through phosphorylation of ventricular myosin regulatory light chain. However, the pathophysiological and therapeutic implications of cMLCK in human heart failure remain unclear. We aimed to investigate whether cMLCK dysregulation causes cardiac dysfunction and whether the restoration of cMLCK could be a novel myotropic therapy for systolic heart failure. METHODS: We generated the knock-in mice (Mylk3+/fs and Mylk3fs/fs) with a familial dilated cardiomyopathy-associated MYLK3 frameshift mutation (MYLK3+/fs) that had been identified previously by us (c.1951-1G>T; p.P639Vfs*15) and the human induced pluripotent stem cell-derived cardiomyocytes from the carrier of the mutation. We also developed a new small-molecule activator of cMLCK (LEUO-1154). RESULTS: Both mice (Mylk3+/fs and Mylk3fs/fs) showed reduced cMLCK expression due to nonsense-mediated messenger RNA decay, reduced MLC2v (ventricular myosin regulatory light chain) phosphorylation in the myocardium, and systolic dysfunction in a cMLCK dose-dependent manner. Consistent with this result, myocardium from the mutant mice showed an increased ratio of cardiac superrelaxation/disordered relaxation states that may contribute to impaired cardiac contractility. The phenotypes observed in the knock-in mice were rescued by cMLCK replenishment through the AAV9_MYLK3 vector. Human induced pluripotent stem cell-derived cardiomyocytes with MYLK3+/fs mutation reduced cMLCK expression by 50% and contractile dysfunction, accompanied by an increased superrelaxation/disordered relaxation ratio. CRISPR-mediated gene correction, or cMLCK replenishment by AAV9_MYLK3 vector, successfully recovered cMLCK expression, the superrelaxation/disordered relaxation ratio, and contractile dysfunction. LEUO-1154 increased human cMLCK activity ≈2-fold in the Vmax for ventricular myosin regulatory light chain phosphorylation without affecting the Km. LEUO-1154 treatment of human induced pluripotent stem cell-derived cardiomyocytes with MYLK3+/fs mutation restored the ventricular myosin regulatory light chain phosphorylation level and superrelaxation/disordered relaxation ratio and improved cardiac contractility without affecting calcium transients, indicating that the cMLCK activator acts as a myotrope. Finally, human myocardium from advanced heart failure with a wide variety of causes had a significantly lower MYLK3/PPP1R12B messenger RNA expression ratio than control hearts, suggesting an altered balance between myosin regulatory light chain kinase and phosphatase in the failing myocardium, irrespective of the causes. CONCLUSIONS: cMLCK dysregulation contributes to the development of cardiac systolic dysfunction in humans. Our strategy to restore cMLCK activity could form the basis of a novel myotropic therapy for advanced systolic heart failure.

Evaluation of the efficacy of creatine chemical exchange saturation transfer imaging in assessing testicular maturity.

Purpose: Microscopic testicular sperm extraction is the most effective treatment for NOA, but the sperm retrieval rate is low and depends on testicular maturity. However, there are limited useful tests to assess testicular maturity. Chemical exchange saturation transfer (CEST) imaging is a new magnetic resonance imaging (MRI) technique that can image the distribution of trace substances in vivo. We focused on the potential role of creatine (Cr) in testes and hypothesized that Cr-CEST could indicate intratesticular spermatogenesis. Methods: We performed Cr-CEST by using 7T MRI on wild-type C57B6/J mice and several types of male infertility models such as Sertoli-cell only (SCO) (Kitw/Kitwv), maturation arrest (MA) (Zfp541 knockout mouse and Kctd19 knockout mouse), and teratozoospermia (Tbc1d21 knockout mouse). After performing Cr-CEST, histological analysis was performed. Results: The SCO and MA models showed decreased CEST signal intensity (p < 0.05), while no reduction was observed in the teratozoospermia model (p = 1.0). CEST signal intensity increased as the spermatogenesis stage progressed from the SCO model to the MA and teratozoospermia models. Furthermore, CEST signal intensity was reduced in 4-week-old wild-type mice with immature testes (p < 0.05). Conclusions: This study suggests that Cr-CEST evaluates intratesticular spermatogenesis noninvasively and provides a new therapeutic strategy for treating male infertility.

Creatine Chemical Exchange Saturation Transfer (Cr-CEST) Imaging Can Evaluate Cisplatin-induced Testicular Damage.

PURPOSE: This study aimed to investigate the ability of creatine-chemical exchange saturation transfer (Cr-CEST) technique assessed through 7-T MRI to evaluate cisplatin-induced testicular damage. METHODS: We used 8-10 weeks C57BL/6 mice (n = 10) that were divided into a control group (n = 5) and a cisplatin-treated group (n = 5). The cisplatin group received cisplatin at a dose of 15 mg/kg, via intraperitoneal injection, while the control group received saline. MR images of mouse testes were acquired under anesthesia 18 days after the injection using a horizontal 7-T scanner. The pulse sequence consisted of rapid acquisition with a relaxation enhancement (RARE) with magnetization transfer. The Z-spectra were collected using a 2000-ms saturation pulse at a B1 amplitude of 1.2 µT, with frequencies varying from -4.8 to +4.8 parts per million (ppm). Maps of magnetization transfer ratio with asymmetric analysis (MTRasym) were reconstructed at a Cr metabolite concentration of 1.8 ppm. RESULTS: The Cr-CEST effect was significantly reduced in the cisplatin-treated group compared to the control group (MTRasym of control mice vs. cisplatin-treated mice: 6.9 [6-7.5] vs. 5.2 [4-5.5], P = 0.008). Correlation analysis revealed a strong correlation between the Cr-CEST effect and the pathological score (ρ = 0.93, P < 0.001). CONCLUSION: Cr-CEST MRI can be useful for the evaluation of cisplatin-induced testicular damage in mice.

Pathophysiological evaluations of initial plaque development after heart transplantation via serial multimodality imaging and cytokine assessments.

BACKGROUND: Detailed morphological characteristics of de novo and donor-transmitted plaques and the association of serum T-lymphocyte cytokine levels with plaque progression of coronary allograft vasculopathy within 1 year after heart transplantation are unknown. METHODS: In this retrospective analysis of data in a prospectively maintained database, 40 heart transplant recipients were included. We performed serial 3 vessel optical coherence tomography and intravascular ultrasound analyses, at the 8 week (baseline) and 12 month post-transplantation follow-ups, and serum cytokine measurements (n = 23). The correlation between serum cytokines and Δplaque burden (between baseline and follow-up) was evaluated depending on plaque morphology. RESULTS: Thirteen de novo plaques (maximum intimal thickness ≥0.5 mm at the 12 month follow-up without plaques at baseline) were identified in 8 recipients, and 31 donor-transmitted plaques (maximum intimal thickness ≥0.5 mm at baseline) were detected in 17 recipients. Compared with donor-transmitted plaques, the Δplaque burden in the de novo plaques, with mainly fibrous morphology, was high (38.8% [29.6%-41.2%] vs 8.7% [1.33%-13.6%], p < 0.001). Stratification of the morphology of donor-transmitted plaques revealed that the Δplaque burden in fibrous plaques (10.6% [7.0%-18.0%]) was similar to that in fibroatheroma (10.3% [8.7%-23.8%]). Serum interleukin-31 levels at baseline correlated with fibrous plaque proliferation (r = 0.73, p = 0.007) even under immunosuppressive conditions, whereas other cytokines (interleukin-1ß, interleukin-17, and interferon-gamma) were mostly undetectable. CONCLUSIONS: Intimal fibrous proliferation contributed to the progression of donor-transmitted and de novo plaques. Serum interleukin-31 levels at baseline may contribute to intimal fibrous proliferation within 1 year after heart transplantation.

Loss-of-function mutations in the co-chaperone protein BAG5 cause dilated cardiomyopathy requiring heart transplantation.

Dilated cardiomyopathy (DCM) is a major cause of heart failure, characterized by ventricular dilatation and systolic dysfunction. Familial DCM is reportedly caused by mutations in more than 50 genes, requiring precise disease stratification based on genetic information. However, the underlying genetic causes of 60 to 80% of familial DCM cases remain unknown. Here, we identified that homozygous truncating mutations in the gene encoding Bcl-2­associated athanogene (BAG) co-chaperone 5 (BAG5) caused inherited DCM in five patients among four unrelated families with complete penetrance. BAG5 acts as a nucleotide exchange factor for heat shock cognate 71 kDa protein (HSC70), promoting adenosine diphosphate release and activating HSC70-mediated protein folding. Bag5 mutant knock-in mice exhibited ventricular dilatation, arrhythmogenicity, and poor prognosis under catecholamine stimulation, recapitulating the human DCM phenotype, and administration of an adeno-associated virus 9 vector carrying the wild-type BAG5 gene could fully ameliorate these DCM phenotypes. Immunocytochemical analysis revealed that BAG5 localized to junctional membrane complexes (JMCs), critical microdomains for calcium handling. Bag5-mutant mouse cardiomyocytes exhibited decreased abundance of functional JMC proteins under catecholamine stimulation, disrupted JMC structure, and calcium handling abnormalities. We also identified heterozygous truncating mutations in three patients with tachycardia-induced cardiomyopathy, a reversible DCM subtype associated with abnormal calcium homeostasis. Our study suggests that loss-of-function mutations in BAG5 can cause DCM, that BAG5 may be a target for genetic testing in cases of DCM, and that gene therapy may potentially be a treatment for this disease.

Phospholamban p.Arg14del Cardiomyopathy: A Japanese Case Series.

Phospholamban p.Arg14del is reported to cause hereditary cardiomyopathy with malignant ventricular tachycardia (VT) and advanced heart failure. However, the clinical courses of Japanese cardiomyopathy patients with phospholamban p.Arg14del remain uncharacterized. We identified five patients with this variant. All patients were diagnosed with dilated cardiomyopathy (DCM), developed end-stage heart failure and experienced VT requiring implantable cardioverter defibrillator discharge. Four patients survived after implantation of a left ventricular assist device (LVAD), while one patient who refused LVAD implantation died of heart failure. Based on the severe course of the disease, we propose genetic screening for phospholamban p.Arg14del in DCM patients.

Aberrant accumulation of TMEM43 accompanied by perturbed transmural gene expression in arrhythmogenic cardiomyopathy.

Arrhythmogenic cardiomyopathy (ACM) caused by TMEM43 p.S358L is a fully penetrant heart disease that results in impaired cardiac function or fatal arrhythmia. However, the molecular mechanism of ACM caused by the TMEM43 variant has not yet been fully elucidated. In this study, we generated knock-in (KI) rats harboring a Tmem43 p.S358L mutation and established induced pluripotent stem cells (iPSCs) from patients based on the identification of TMEM43 p.S358L variant from a family with ACM. The Tmem43-S358L KI rats exhibited ventricular arrhythmia and fibrotic myocardial replacement in the subepicardium, which recapitulated the human ACM phenotype. The four-transmembrane protein TMEM43 with the p.S358L variant (TMEM43S358L ) was found to be modified by N-linked glycosylation in both KI rat cardiomyocytes and patient-specific iPSC-derived cardiomyocytes. TMEM43S358L glycosylation increased under the conditions of enhanced endoplasmic reticulum (ER) stress caused by pharmacological stimulation or age-dependent decline of the ER function. Intriguingly, the specific glycosylation of TMEM43S358L resulted from the altered membrane topology of TMEM43. Moreover, unlike TMEM43WT , which is mainly localized to the ER, TMEM43S358L accumulated at the nuclear envelope of cardiomyocytes with the increase in glycosylation. Finally, our comprehensive transcriptomic analysis demonstrated that the regional differences in gene expression patterns between the inner and outer layers observed in the wild type myocardium were partially diminished in the KI myocardium prior to exhibiting histological changes indicative of ACM. Altogether, these findings suggest that the aberrant accumulation of TMEM43S358L underlies the pathogenesis of ACM caused by TMEM43 p.S358L variant by affecting the transmural gene expression within the myocardium.

Visualization of Spatial Distribution of Spermatogenesis in Mouse Testes Using Creatine Chemical Exchange Saturation Transfer Imaging.

BACKGROUND: When determining treatment strategies for male infertility, it is important to evaluate spermatogenesis and its spatial distribution in the testes. PURPOSE: To investigate the usefulness of creatine chemical exchange saturation transfer (CrCEST) imaging for evaluating spermatogenesis and its spatial distribution. STUDY TYPE: Prospective. ANIMAL MODEL: C57BL/6 control mice (n = 5) and model mice of male infertility induced by whole testis X-ray irradiation (n = 11) or localized X-ray irradiation to lower regions of testes (n = 3). FIELD STRENGTH/SEQUENCE: A 11.7-T vertical-bore magnetic resonance imaging (MRI)/segmented fast low-angle shot acquisition for CEST. ASSESSMENT: The magnetization transfer ratio for the CrCEST effect (MTRCr* ) was calculated in each testis of the control mice and X-ray irradiation model mice at 10, 15, 20, and 30 days after irradiation. Correlation analysis was performed between MTRCr* and Johnsen's score, a histological score for spermatogenesis. In the localized X-ray irradiation model, regional MTRCr* and Johnsen's score were calculated for correlation analysis. STATISTICAL TESTS: Unpaired t-test, one-way analysis of variance with Tukey's HSD test and Pearson's correlation analysis. A P value < 0.05 was considered statistically significant. RESULTS: In the irradiation model, CrCEST imaging revealed a significant linear decrease of MTRCr* after irradiation (control, 8.7 ± 0.6; 10 days, 7.9 ± 0.8; 15 days, 6.5 ± 0.6; 20 days, 5.4 ± 1.0; 30 days, 4.4 ± 0.8). A significant linear correlation was found between MTRCr* and Johnsen's score (Pearson's correlation coefficient (r) = 0.79). In the localized irradiation model, CrCEST imaging visualized a significant regional decrease of MTRCr* in the unshielded region (shielded, 6.9 ± 0.7; unshielded, 4.9 ± 1.0), and a significant linear correlation was found between regional MTRCr* and Johnsen's score (r = 0.78). DATA CONCLUSION: Testicular CrCEST effects correlated well with spermatogenesis. CrCEST imaging was useful for evaluating spermatogenesis and its spatial distribution. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.

Focal severe decrease in myocardial technetium-99 m sestamibi uptake indicates ventricular irreversibility in patients with dilated cardiomyopathy.

OBJECTIVE: Technetium-99 m sestamibi (99mTc-MIBI) scintigraphy can identify non-viable left ventricular (LV) myocardium. However, the optimal cut-off value and the details of decreased 99mTc-MIBI uptake of the non-viable LV myocardium in patients with dilated cardiomyopathy (DCM) have not been well established. This study aimed to evaluate the decrease in 99mTc-MIBI uptake in each segment and in the whole LV myocardium, and to determine cut-off values for identifying non-viable LV myocardium in DCM patients. METHODS: Overall, 53 DCM patients with reduced LV ejection fraction (LVEF ≤ 40%) who underwent 99mTc-MIBI scintigraphy and any optimization of heart failure treatments were evaluated. LV myocardium was classified as viable or non-viable based on the absolute increase in LVEF of ≥ 10% unit leading to an LVEF of > 40% at follow-up, respectively. The decrease in myocardial 99mTc-MIBI uptake in each of the 17 segments was evaluated using three indices determined by different thresholds or standard references: segmental %uptake, rest score, and defect extent. Changes in the whole LV myocardium were evaluated by the minimum %uptake, and the summed rest score (SRS) and extent of LV defect were obtained using summed data of 17 segments. RESULTS: Segmental evaluation indicated a mild decrease in 99mTc-MIBI uptake in 18 patients with viable LV myocardium, whereas focal severe decrease in uptake was observed in patients with non-viable LV myocardium. In the receiver-operating characteristic curve analysis, the cut-off values of minimum %uptake, SRS, and LV defect extent for predicting non-viable LV were 39% (p < 0.01, area under the curve [AUC]: 0.87), 10 (p < 0.01, AUC: 0.91), and 23% (p < 0.01, AUC: 0.92), respectively. CONCLUSIONS: In DCM patients, myocardial 99mTc-MIBI %uptake of < 40% indicated non-viable myocardium. The focal and severe decrease in uptake in approximately more than a quarter of the LV myocardium may indicate non-viable LV.

The CR9 element is a novel mechanical load-responsive enhancer that regulates natriuretic peptide genes expression.

Enhancers regulate gene expressions in a tissue- and pathology-specific manner by altering its activities. Plasma levels of atrial and brain natriuretic peptides, encoded by the Nppa and Nppb, respectively, and synthesized predominantly in cardiomyocytes, vary depending on the severity of heart failure. We previously identified the noncoding conserved region 9 (CR9) element as a putative Nppb enhancer at 22-kb upstream from the Nppb gene. However, its regulatory mechanism remains unknown. Here, we therefore investigated the mechanism of CR9 activation in cardiomyocytes using different kinds of drugs that induce either cardiac hypertrophy or cardiac failure accompanied by natriuretic peptides upregulation. Chronic treatment of mice with either catecholamines or doxorubicin increased CR9 activity during the progression of cardiac hypertrophy to failure, which is accompanied by proportional increases in Nppb expression. Conversely, for cultured cardiomyocytes, doxorubicin decreased CR9 activity and Nppb expression, while catecholamines increased both. However, exposing cultured cardiomyocytes to mechanical loads, such as mechanical stretch or hydrostatic pressure, upregulate CR9 activity and Nppb expression even in the presence of doxorubicin. Furthermore, the enhancement of CR9 activity and Nppa and Nppb expressions by either catecholamines or mechanical loads can be blunted by suppressing mechanosensing and mechanotransduction pathways, such as muscle LIM protein (MLP) or myosin tension. Finally, the CR9 element showed a more robust and cell-specific response to mechanical loads than the -520-bp BNP promoter. We concluded that the CR9 element is a novel enhancer that responds to mechanical loads by upregulating natriuretic peptides expression in cardiomyocytes.

Cardiac Fibroblasts Play Pathogenic Roles in Idiopathic Restrictive Cardiomyopathy.

BACKGROUND: Restrictive cardiomyopathy (RCM) is characterized by impaired ventricular relaxation. Although several mutations were reported in some patients, no mutations were identified in cardiomyocyte expressing genes of other patients, indicating that pathological mechanisms underlying RCM could not be determined by cardiomyocytes only. Cardiac fibroblasts (CFs) are a major cell population in the heart; however, the pathological roles of CFs in cardiomyopathy are not fully understood.Methods and Results:This study established 4 primary culture lines of CFs from RCM patients and analyzed their cellular physiology, the effects on the contraction and relaxation ability of healthy cardiomyocytes under co-culture with CFs, and RNA sequencing. Three of four patients hadTNNI3mutations. There were no significant alterations in cell proliferation, apoptosis, migration, activation, and attachment. However, when CFs from RCM patients were co-cultured with healthy cardiomyocytes, the relaxation velocity of cardiomyocytes was significantly impaired both under direct and indirect co-culture conditions. RNA sequencing revealed that gene expression profiles of CFs in RCM were clearly distinct from healthy CFs. The differential expression gene analysis identified that several extracellular matrix components and cytokine expressions were dysregulated in CFs from RCM patients. CONCLUSIONS: The comprehensive gene expression patterns were altered in RCM-derived CFs, which deteriorated the relaxation ability of cardiomyocytes. The specific changes in extracellular matrix composition and cytokine secretion from CFs might affect pathological behavior of cardiomyocytes in RCM.

Alpha-Klotho is a novel predictor of treatment responsiveness in patients with heart failure.

Heart failure is a major cause of death with an increasing population of elderly individuals. Several studies have demonstrated the involvement of soluble alpha-Klotho (sαKl) in various diseases. However, the correlation between sαKl and heart failure remains to be understood. The aim of this study is to investigate the levels and role of sαKl in patients with heart failure. Twenty-eight consecutive patients with acute heart failure (19 male, 9 female), admitted to the Osaka University Hospital from 2010 to 2018, were enrolled in this study. Mean NYHA score, left ventricular ejection fraction and BNP were 3.3, 17.0% and 588 pg/mL, respectively. SαKl significantly increased in heart failure patients. SαKl on admission were significantly higher in patients with heart failure who showed improvement after intensive treatment than that in patients who did not show improvement after the treatment. SαKl levels decreased significantly in patients who showed improvement. Interestingly, sαKl levels increased in male patients with heart failure, but not in female patients. Our data suggest that soluble αKl may be a novel biomarker for the responsiveness against treatment in patients with heart failure with reduced ejection fraction. Our findings may help developing a personalized therapy for different patients with heart failure.

Multiple percutaneous coronary interventions worsen outcomes for subsequent surgical correction of chronic ischemic mitral regurgitation.

Objective: We investigated whether or not a history of multiple percutaneous coronary interventions (PCIs) is associated with clinical outcomes after surgery for ischemic mitral regurgitation. Methods: A total of 309 patients with chronic ischemic mitral regurgitation and left ventricular ejection fraction ≤40% who underwent restrictive mitral annuloplasty were classified as follows: patients with no or 1 previous PCI (nonmultiple PCI group [n = 211]) and patients with 2 or more previous PCIs (multiple PCIs group [n = 98]). Mean follow-up duration was 53 ± 40 months. Results: Before surgery, there were no intergroup differences in patient demographic characteristics except for lower estimated glomerular filtration rate in patients with multiple PCIs. These patients underwent concomitant coronary artery bypass grafting less frequently with a lower number of distal anastomoses (P < .05 for both). The 30-day mortality was 3.3% and 2.0% in the nonmultiple and multiple PCIs group, respectively (P = .72). During follow-up, there were 157 deaths. Patients with multiple PCIs showed lower 5-year survival rate (44% vs 64%; P = .002). After adjustments with inverse-probability-of-treatment weighting, multiple PCIs history was an independent risk factor for mortality (adjusted hazard ratio, 1.4; 95% confidential interval, 1.1-1.7; P = .002). Patients with multiple PCIs showed less improvement in left ventricular ejection fraction (interaction effect P < .001). Conclusions: In patients with ischemic mitral regurgitation, a history of previous multiple PCIs was associated with increased risk of long-term postoperative mortality, with less improvement in left ventricular ejection fraction.

AMPK regulates cell shape of cardiomyocytes by modulating turnover of microtubules through CLIP-170.

AMP-activated protein kinase (AMPK) is a multifunctional kinase that regulates microtubule (MT) dynamic instability through CLIP-170 phosphorylation; however, its physiological relevance in vivo remains to be elucidated. In this study, we identified an active form of AMPK localized at the intercalated disks in the heart, a specific cell-cell junction present between cardiomyocytes. A contractile inhibitor, MYK-461, prevented the localization of AMPK at the intercalated disks, and the effect was reversed by the removal of MYK-461, suggesting that the localization of AMPK is regulated by mechanical stress. Time-lapse imaging analysis revealed that the inhibition of CLIP-170 Ser-311 phosphorylation by AMPK leads to the accumulation of MTs at the intercalated disks. Interestingly, MYK-461 increased the individual cell area of cardiomyocytes in CLIP-170 phosphorylation-dependent manner. Moreover, heart-specific CLIP-170 S311A transgenic mice demonstrated elongation of cardiomyocytes along with accumulated MTs, leading to progressive decline in cardiac contraction. In conclusion, these findings suggest that AMPK regulates the cell shape and aspect ratio of cardiomyocytes by modulating the turnover of MTs through homeostatic phosphorylation of CLIP-170 at the intercalated disks.

Accurate Estimation of the Duration of Testicular Ischemia Using Creatine Chemical Exchange Saturation Transfer (CrCEST) Imaging.

BACKGROUND: In the management of testicular torsion, estimating the duration of testicular ischemia is essential for deciding on an appropriate surgical treatment, but there are currently limited evaluation methods. PURPOSE: To perform testicular creatine chemical exchange saturation transfer (CrCEST) imaging and to evaluate its ability to accurately estimate the duration of testicular ischemia. STUDY TYPE: Prospective. ANIMAL MODEL: C57BL/6 control mice (n = 6) and testicular ischemia models induced by clamping the spermatic cord (n = 14). Eight of testicular ischemia models were serially imaged at two or three timepoints and a total of 26 images of ischemic testis were obtained. The ischemic duration ranged from 6-42 hours. FIELD STRENGTH/SEQUENCE: 11.7T vertical-bore MRI/segment fast low-angle shot acquisition for CEST. ASSESSMENT: CrCEST imaging was performed and the magnetization transfer ratio for the CrCEST effect (MTRCr** ) was calculated in control mice and testicular ischemia models. Correlation analysis between the duration of testicular ischemia and MTRCr** decline was performed. STATISTICAL TESTS: Paired t-test, and Pearson's correlation analysis. RESULTS: In control mice, the CrCEST effect in testes was significantly more than five times higher than that in skeletal muscle. MTRCr** did not differ significantly between the right and left testes (8.6 ± 0.8 vs. 8.3 ± 0.6, P = 0.96). In testicular ischemia models, MTRCr** of ischemic testes was significantly lower than that of controls (4 ± 2 vs. 8.9 ± 0.6, P < 0.001). Correlation analysis revealed a strong linear correlation between MTRCr** decline and the duration of ischemia (r = 0.96, P < 0.001). DATA CONCLUSION: A decreased CrCEST effect in ischemic testes correlated well with ischemic duration. Testicular CrCEST imaging was useful for accurately estimating the duration of testicular ischemia. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY STAGE: 2.