Prognostic value of metabolic dysfunction-associated steatotic liver disease over coronary computed tomography angiography findings: comparison with no-alcoholic fatty liver disease.

BACKGROUND: Metabolic dysfunction-associated steatotic liver disease (MASLD) is the proposed name change for non-alcoholic fatty liver disease (NAFLD). This study aimed to investigate the association of cardiovascular disease risk with MASLD and NAFLD in patients who underwent clinically indicated coronary computed tomography angiography (CCTA). METHODS: This retrospective study included 2289 patients (60% men; mean age: 68 years) with no history of coronary artery disease who underwent CCTA. The steatotic liver was defined as a hepatic-to-spleen attenuation ratio of < 1.0 on CT just before CCTA. MASLD is defined as the presence of hepatic steatosis along with at least one of the five cardiometabolic risk factors. Adverse CCTA findings were defined as obstructive and/or high-risk plaques. Major adverse cardiac events (MACE) encompassed composite coronary events, including cardiovascular death, acute coronary syndrome, and late coronary revascularization. RESULTS: MASLD and NAFLD were identified in 415 (18%) and 368 (16%) patients, respectively. Adverse CCTA findings were observed in 40% and 38% of the patients with MASLD and with NAFLD, respectively. Adverse CCTA findings were significantly associated with MASLD (p = 0.007) but not NAFLD (p = 0.253). During a median follow-up of 4.4 years, 102 (4.4%) MACE were observed. MASLD was significantly associated with MACE (hazard ratio 1.82, 95% CI 1.18-2.83, p = 0.007), while its association with NAFLD was not significant (p = 0.070). By incorporating MASLD into a prediction model of MACE, including the risk score and adverse CCTA findings, global chi-squared values significantly increased from 87.0 to 94.1 (p = 0.008). CONCLUSIONS: Patients with MASLD are likely to have a higher risk of cardiovascular disease than those with NAFLD. Concurrent assessment of MASLD during CCTA improves the identification of patients at a higher risk of cardiovascular disease among those with clinically indicated CCTA.

Morphological Features of Patent Foramen Ovale Compared Between Older and Young Patients With Cryptogenic Ischemic Stroke.

BACKGROUND: The morphology of a patent foramen ovale (PFO) with a high-risk for cryptogenic ischemic stroke (CS) is an important factor in the selection of patients for transcatheter closure, but the morphological features of PFO in older patients with a history of CS are less known because the most data are obtained from younger patients.Methods and Results: The study included 169 patients who had a history of CS and PFO. The prevalence of high-risk morphologies of PFO assessed by transesophageal echocardiography was compared between patients aged ≥60 years and patients aged <60 years. We also assessed the presence of septal malalignment of PFO on the aortic wall. The probability of CS due to PFO was evaluated using the PFO-Associated Stroke Causal Likelihood classification system. Patients aged ≥60 years had a significantly higher prevalence of atrial septal aneurysm than patients aged <60 years. The prevalence of large right-to-left shunt, long-tunnel of PFO, or Eustachian valve or Chiari's network was similar between patients aged ≥60 years and <60 years. Septal malalignment was observed more frequently in patients aged ≥60 years than in those <60 years old. Nearly 90% of patients aged ≥60 years were classified as 'possible' in the PFO-Associated Stroke Causal Likelihood classification system. CONCLUSIONS: High-risk morphologies of PFO are common in older patients with a history of CS, as well as in younger patients.

Induced Pluripotent Stem Cell-Derived Cardiomyocytes Therapy for Ischemic Heart Disease in Animal Model: A Meta-Analysis.

Ischemic heart disease (IHD) poses a significant challenge in cardiovascular health, with current treatments showing limited success. Induced pluripotent derived-cardiomyocyte (iPSC-CM) therapy within regenerative medicine offers potential for IHD patients, although its clinical impacts remain uncertain. This study utilizes meta-analysis to assess iPSC-CM outcomes in terms of efficacy and safety in IHD animal model studies. A meta-analysis encompassing PUBMED, ScienceDirect, Web of Science, and the Cochrane Library databases, from inception until October 2023, investigated iPSC therapy effects on cardiac function and safety outcomes. Among 51 eligible studies involving 1012 animals, despite substantial heterogeneity, the iPSC-CM transplantation improved left ventricular ejection fraction (LVEF) by 8.23% (95% CI, 7.15 to 9.32%; p < 0.001) compared to control groups. Additionally, cell-based treatment reduced the left ventricle fibrosis area and showed a tendency to reduce left ventricular end-systolic volume (LVESV) and end-diastolic volume (LVEDV). No significant differences emerged in mortality and arrhythmia risk between iPSC-CM treatment and control groups. In conclusion, this meta-analysis indicates iPSC-CM therapy's promise as a safe and beneficial intervention for enhancing heart function in IHD. However, due to observed heterogeneity, the efficacy of this treatment must be further explored through large randomized controlled trials based on rigorous research design.

Perspectives of hospitalized heart failure patients: preferred and perceived participation roles in treatment decisions.

Shared decision-making (SDM) is a pivotal process in seeking optimal individual treatment and incorporating clinical evidence and patients' autonomous preferences. However, patients' actual attitudes toward participation in decision-making for state-of-the-art heart failure (HF) treatment remain unclear. We conducted a questionnaire-based survey distributed by nurses and physicians specializing in HF care to assess patients' preferred and perceived participation roles in treatment decision-making during the index hospitalization, rated on five scales (from extremely passive to purely autonomous attitudes). Simultaneously, we investigated the important factors underlying treatment decision-making from the perspective of hospitalized HF patients. Of the 202 patients who were approached by our multidisciplinary HF team between 2017 and 2020, 166 (82.2%) completed the survey. Logistic regression analyses were conducted to identify the clinical determinants of patients who reported that they left all decisions to physicians (i.e., extremely passive attitude). Of the 166 participants (male 67.5%, median age 73 years), 32.5% preferred an extremely passive attitude, while 61.4% reported that they actually chose an extremely passive attitude. A sole determinant of choosing an extremely passive decision-making role was lower educational status (odds ratio: 2.11, 95% confidence interval 1.11-4.00). The most important factor underlying the decision-making was "Physician recommendation" (89.2%). Notably, less than 50% considered "In alignment with my values and preferences" as an important factor underlying treatment decision-making. The majority of HF patients reported that they chose an extremely passive approach, and patients prioritized physician recommendation over their own values and preferences.

Development of non-bias phenotypic drug screening for cardiomyocyte hypertrophy by image segmentation using deep learning.

The number of patients with heart failure and related deaths is rapidly increasing worldwide, making it a major problem. Cardiac hypertrophy is a crucial preliminary step in heart failure, but its treatment has not yet been fully successful. In this study, we established a system to evaluate cardiomyocyte hypertrophy using a deep learning-based high-throughput screening system and identified drugs that inhibit it. First, primary cultured cardiomyocytes from neonatal rats were stimulated by both angiotensin II and endothelin-1, and cellular images were captured using a phase-contrast microscope. Subsequently, we used a deep learning model for instance segmentation and established a system to automatically and unbiasedly evaluate the cardiomyocyte size and perimeter. Using this system, we screened 100 FDA-approved drugs library and identified 12 drugs that inhibited cardiomyocyte hypertrophy. We focused on ezetimibe, a cholesterol absorption inhibitor, that inhibited cardiomyocyte hypertrophy in a dose-dependent manner in vitro. Additionally, ezetimibe improved the cardiac dysfunction induced by pressure overload in mice. These results suggest that the deep learning-based system is useful for the evaluation of cardiomyocyte hypertrophy and drug screening, leading to the development of new treatments for heart failure.

Recent Technological Innovations to Promote Cardiovascular Research.

Cardiovascular disease (CVD) is a major global health concern. Several therapeutic strategies for CVDs are available, such as medicine, cardiac assist devices, and heart transplantation. However, they are insufficient for the treatment of severe CVD. To develop novel, innovative treatment approaches for CVDs, it is imperative to understand the underlying pathophysiology and to undertake basic research on this facet. The generation of induced pluripotent stem (iPS) cells has opened avenues for developing new strategies for disease analysis and drug development. This technology has made it possible to obtain pluripotent stem cells from patients with genetic disorders, model the disease in a dish, and use such cells for future regeneration therapy. Meanwhile, artificial intelligence (AI), which is widely used for big data analysis in basic research, has potential in various applications in medicine. New tools such as iPS cells and AI can provide much needed novel insights into CVDs. This review focuses on the recent progress in cardiovascular research using these new technologies.

Sleep-disordered breathing is independently associated with elevated natriuretic peptide levels in patients with cardiovascular diseases.

Sleep disorders and sleep duration have attracted considerable attention as potential modifiable risk factors for the development and progression of heart failure (HF). However, whether these sleep behaviors could aggravate the underlying cardiac condition remains ambiguous. We evaluated the associations between the levels of plasma B-type natriuretic peptide (BNP) and sleep-disordered breathing (SDB), sleep quality and quantity, or daytime sleepiness in cardiovascular diseases (CVD) patients. A total of 1717 consecutive patients with CVD [median age, 66 years (55-74 years); female, 27.5%] were enrolled. SDB was screened by nocturnal pulse oximetry; sleep quality and quantity were determined by Pittsburg Sleep Quality Index, and daytime sleepiness was examined by Epworth Sleepiness Scale. The median plasma BNP level was 54.9 pg/ml (23.5-146.4 pg/ml). Multiple regression analyses showed that the BNP level in the highest quintile (BNP > 181.8 pg/ml) was associated with SDB (severe: OR, 5.88; 95% CI 3.17-10.88; moderate: OR, 3.62; 95% CI 2.17-6.02; mild: OR, 2.22: 95% CI 1.42-3.47). There were no significant associations between other sleep parameters and higher BNP levels. The relationship between SDB and BNP levels was unchanged regardless of the previous history of symptomatic HF. SDB was independently associated with the elevated plasma BNP level in patients with a variety of CVD.

Sex differences in sleep and psychological disturbances among patients admitted for cardiovascular diseases.

BACKGROUND: Understanding sex differences is critical for improving outcomes in patients with cardiovascular conditions. Sleep and psychological disturbances contribute to the development and progression of cardiovascular diseases, and important sex differences persist in their incidence and association with clinical outcomes. METHODS: Sex-based variation in sleep and psychological disturbances were assessed in consecutive patients with cardiovascular diseases in a single university hospital. The prevalence of insomnia, sleep disordered breathing (SDB), anxiety, and depression was assessed using the Pittsburgh Sleep Quality Index (PSQI), nocturnal pulse oximeter, and the Hospital Anxiety and Depression Scale (HADS). The effect of sex on the prevalence of sleep and psychological disturbances as well as their associations was quantified using multivariate logistic regression models. RESULTS: Among 1,233 patients (mean age 63.6 years, 25% women), women were significantly less likely than men to experience SDB (17.5% vs 31.5%, p < 0.001), but more likely to report an increased burden of insomnia (54.7% vs 43.3%, p = 0.001) and depression (23.9% vs 16.7%, p = 0.004). Insomnia was associated with depression, which was more remarkable among women (p value for interaction: 0.039). SDB was associated with anxiety among women but not men (p value for interaction: 0.003). There was no significant difference in the prevalence of anxiety between women and men. CONCLUSIONS: Among patients with cardiovascular disease, women reported an increased burden of insomnia and depression compared to men. The association between sleep and psychological disturbances may be more pronounced in women, suggesting that cardiologists should increase efforts for identification of such comorbidities and administer corresponding treatment, especially in women.

Prognostic Understanding and Preference for the Communication Process with Physicians in Hospitalized Heart Failure Patients.

BACKGROUND: Heart failure (HF) is a highly prevalent, heterogeneous, and life-threatening condition. Precise prognostic understanding is essential for effective decision making, but little is known about patients' attitudes toward prognostic communication with their physicians. METHODS AND RESULTS: We conducted a questionnaire survey, consisting of patients' prognostic understanding, preferences for information disclosure, and depressive symptoms, among hospitalized patients with HF (92 items in total). Individual 2-year survival rates were calculated using the Seattle Heart Failure Model, and its agreement level with patient self-expectations of 2-year survival were assessed. A total of 113 patients completed the survey (male 65.5%, median age 75.0 years, interquartile range 66.0-81.0 years). Compared with the Seattle Heart Failure Model prediction, patient expectation of 2-year survival was matched only in 27.8% of patients; their agreement level was low (weighted kappa = 0.11). Notably, 50.9% wished to know "more," although 27.7% felt that they did not have an adequate prognostic discussion. Compared with the known prognostic variables (eg, age and HF severity), logistic regression analysis demonstrated that female and less depressive patients were associated with patients' preference for "more" prognostic discussion. CONCLUSIONS: Patients' overall prognostic understanding was suboptimal. The communication process requires further improvement for patients to accurately understand their HF prognosis and be involved in making a better informed decision.

Predictors of New-Onset Atrial Tachyarrhythmias After Transcatheter Atrial Septal Defect Closure in Adults.

BACKGROUND: New-onset atrial tachyarrhythmia (ATA) often develops after atrial septal defect (ASD) closure. Its development raises some potential concerns such as stroke and bleeding complications caused by anticoagulant therapy and limited access to the left atrium for catheter ablation. Although it is essential to identify the risk factors of new-onset ATA, few studies have examined these factors. This study investigated unknown risk factors for the development of new-onset ATA after transcatheter ASD closure in patients without a history of ATA. METHODS: A total of 238 patients without a history of ATA, aged ≥18 years and who underwent transcatheter ASD closure at the current hospital were reviewed. Patient characteristics were compared between the groups with and without new-onset ATA. The factors associated with new-onset ATA were examined using univariate and multivariable analyses. RESULTS: Thirteen (13) (5.5%) patients experienced ATA during follow-up (mean, 21±14 months). Compared with patients without new-onset ATA, patients with new-onset ATA were older (48±18 vs 66±11 years; p<0.001) and had high brain natriuretic peptide (BNP) levels (36±36 vs 177±306 pg/mL; p<0.001). On multivariable analysis, BNP ≥40 pg/mL before ASD closure was associated with new-onset ATA after adjusting for age (OR, 4.91; 95% CI, 1.22-19.8; p=0.025). CONCLUSION: Patients with BNP levels >40 pg/mL before transcatheter ASD closure may have a higher risk of developing new-onset ATA.

Factors related to instrumental activities of daily living in persons with chronic thromboembolic pulmonary hypertension.

Instrumental activities of daily living (IADL) are significantly related to quality of life and mortality among individuals with heart disease. However, few reports have examined IADL in persons with chronic thromboembolic pulmonary hypertension (CTEPH). The aim of this study was to clarify factors related to IADL in persons with CTEPH. This retrospective, observational study enrolled 163 persons with CTEPH (mean ± standard deviation age = 65 ± 13 years; 68% female) admitted to the Department of Cardiology at Keio University Hospital between January 2015 and July 2019. The Frenchay Activities Index (FAI) was used to assess IADL. Age, sex, body mass index, World Health Organization functional class (WHO-FC), cardiac function (mean pulmonary arterial pressure, mean right atrial pressure, pulmonary capillary wedge pressure, and cardiac index), pulmonary function (percentage vital capacity, percentage forced expiratory volume in 1 s, diffusion capacity of carbon monoxide (DLCO)/alveolar volume (VA)), physical function (knee extension strength and walking speed), and 6-min walking distance (6MWD) were assessed. Multiple regression analysis was performed to identify factors significantly associated with FAI. Mean FAI was 25 ± 8. Univariate analysis showed that sex, WHO-FC, DLCO/VA, walking speed, and 6MWD were correlated with FAI. Multiple regression analysis showed that 6MWD (sß = 0.338, 95% CI 0.014-0.034, p < .001), sex (sß = 0.268, 95% CI 2.238-7.165, p < .001), and DLCO/VA (sß = 0.257, 95% CI 1.011-3.528, p < .001) were significantly correlated with FAI (R2 = 0.261). IADL were associated with exercise tolerance, sex, and DLCO/VA in persons with CTEPH. In the future, more details of IADL are expected to be clarified by analyzing individual components of IADL and investigating social background characteristics, including living environment.

Stem Cell Aging in Skeletal Muscle Regeneration and Disease.

Skeletal muscle comprises 30-40% of the weight of a healthy human body and is required for voluntary movements in humans. Mature skeletal muscle is formed by multinuclear cells, which are called myofibers. Formation of myofibers depends on the proliferation, differentiation, and fusion of muscle progenitor cells during development and after injury. Muscle progenitor cells are derived from muscle satellite (stem) cells (MuSCs), which reside on the surface of the myofiber but beneath the basement membrane. MuSCs play a central role in postnatal maintenance, growth, repair, and regeneration of skeletal muscle. In sedentary adult muscle, MuSCs are mitotically quiescent, but are promptly activated in response to muscle injury. Physiological and chronological aging induces MuSC aging, leading to an impaired regenerative capability. Importantly, in pathological situations, repetitive muscle injury induces early impairment of MuSCs due to stem cell aging and leads to early impairment of regeneration ability. In this review, we discuss (1) the role of MuSCs in muscle regeneration, (2) stem cell aging under physiological and pathological conditions, and (3) prospects related to clinical applications of controlling MuSCs.

Discrepancy between patient-reported quality of life and the prognostic assessment of Japanese patients hospitalized with acute heart failure.

Patient-reported quality of life (PRQL) is a primary therapeutic target for patients with chronic heart failure (HF) and is associated with long-term prognosis. However, its utility in hospitalized HF (HHF) patients in the acute setting remains unclear. We aimed to assess the utility of PRQL (the Kansas City Cardiomyopathy Questionnaire [KCCQ]) in HHF patients and its association with long-term prognosis as well as with the clinical risk score (Get With The Guidelines-Heart Failure [GWTG-HF] risk score). PRQL was evaluated using the KCCQ in consecutive 114 HHF patients. Its association with the composite outcome of all-cause mortality or HF readmission within the first year after discharge was analyzed. Furthermore, its distribution by the clinical risk score (GWTG-HF) was evaluated using Pearson's correlation coefficient. The median KCCQ was 34.9, but was widely distributed (interquartile range 23.7-56.8). After adjustment for known prognostic indicators, the KCCQ was not an independent predictor of the composite outcome within the first year (group with high vs. low KCCQ scores: hazard ratio, 0.67; 95% confidence interval 0.26-1.71). There was no significant correlation between the KCCQ and the GWTG-HF risk score. In conclusion, PRQL during the acute phase of HF was significantly impaired and also varied widely, irrespective of patient characteristics or severity. PRQL assessment and risk prediction for HHF patients in the acute setting seemed to provide two distinct types of information for health care providers.

Selective modulation of local linkages between active transcription and oxidative demethylation activity shapes cardiomyocyte-specific gene-body epigenetic status in mice.

BACKGROUND: Cell-type-specific genes exhibit heterogeneity in genomic contexts and may be subject to different epigenetic regulations through different gene transcriptional processes depending on the cell type involved. The gene-body regions (GBRs) of some cardiomyocyte (CM)-specific genes are long and highly hypomethylated in CMs. To explore the cell-type specificities of epigenetic patterns and functions, multiple epigenetic modifications of GBRs were compared among CMs, liver cells and embryonic stem cells (ESCs). RESULTS: We found that most genes show a moderately negative correlation between transcript levels and gene lengths. As CM-specific genes are generally longer than other cell-type-specific genes, we hypothesized that the gene-body epigenetic features of CMs may support the transcriptional regulation of CM-specific genes. We found gene-body DNA hypomethylation in a CM-specific gene subset co-localized with rare gene-body marks, including RNA polymerase II (Pol II) and p300. Interestingly, 5-hydroxymethylcytosine (5hmC) within the gene body marked cell-type-specific genes at neonatal stages and active gene-body histone mark H3K36 trimethylation declined and overlapped with cell-type-specific gene-body DNA hypomethylation and selective Pol II/p300 accumulation in adulthood. Different combinations of gene-body epigenetic modifications were also observed with genome-wide scale cell-type specificity, revealing the occurrence of dynamic epigenetic rearrangements in GBRs across different cell types. CONCLUSIONS: As 5hmC enrichment proceeded to hypomethylated GBRs, we considered that hypomethylation may not represent a static state but rather an equilibrium state of turnover due to the balance between local methylation linked to transcription and Tet oxidative modification causing demethylation. Accordingly, we conclude that demethylation in CMs can be a used to establish such cell-type-specific epigenetic domains in relation to liver cells. The establishment of cell-type-specific epigenetic control may also change genomic contexts of evolution and may contribute to the development of cell-type-specific transcriptional coordination.

Excessive Daytime Sleepiness Is Associated With Depression Scores, But Not With Sleep-Disordered Breathing in Patients With Cardiovascular Diseases.

BACKGROUND: Excessive daytime sleepiness (EDS) is a significant public health concern, with sleep-disordered breathing (SDB) being a common cause. However, their precise relationship in patients with cardiovascular disease (CVD) is unclear. Furthermore, whether comorbid psychological disorders could contribute to EDS remains unknown. We aimed to assess the prevalence of EDS and its related factors, including SDB and depression, in patients with CVD.Methods and Results:We analyzed data from 1,571 patients admitted for various CVDs in a single university hospital (median age, 67 [56-76] years; 29.6% women). We assessed EDS using the Japanese version of the Epworth Sleepiness Scale (ESS; median 6.0 [4.0-9.0]). The presence of EDS (ESS >10, n=297 [18.9%]) did not differ between patients with and without SDB, which was screened with nocturnal pulse oximetry. In contrast, the patients with EDS had higher depression scores (Hospital Anxiety and Depression Scale subscore for depression [HADS-D] and Patient Healthcare Questionnaire [PHQ]-9). The depression scores, measured by HADS-D (odds ratio [OR] 1.14; 95% confidence interval [CI], 1.07-1.22) and PHQ-9 (OR, 1.14; 95% CI, 1.07-1.20) were independent determinants of EDS. These relationships among EDS, SDB, and depression were consistent among the subgroups with cardiovascular comorbidities. CONCLUSIONS: The presence of EDS is associated with depressive symptoms, but not with SDB, in patients with CVD, suggesting that these patients should be thoroughly assessed for psychological disturbances.

Predictors of high cost after percutaneous coronary intervention: A review from Japanese multicenter registry overviewing the influence of procedural complications.

BACKGROUND: Percutaneous coronary intervention (PCI) is widely used; however, factors of high-cost care after PCI have not been thoroughly investigated. We sought to evaluate the in-hospital costs related to PCI and identify predictors of high costs. METHODS: We extracted 2,354 consecutive PCI cases (1,243 acute cases, 52.8%) from 3 Japanese cardiovascular centers from 2011 to 2015. In-hospital complications were predefined under consensus definitions (eg, acute kidney injury [AKI]). We extracted the facility cost data for each patient's resource under the universal Japanese insurance system. We classified the patients into total cost quartiles and identified predictors for the highest quartile ("high-cost" group). In addition, incremental costs for procedure-related complications were calculated. RESULTS: During the study period, a total of 401 cases (17.0%) experienced procedure-related complications. The in-hospital acute and elective PCI costs per case were US $14,840 (interquartile range [IQR] 11,370-20,070) and US $11,030 (IQR 8929-14,670), respectively. After adjusting for baseline differences, any of the procedure-related complications remained an independent predictor of high costs (acute: odds ratio 1.66, 95% CIs 1.13-2.43; elective: odds ratio 3.73, 95% CIs 1.96-7.11). Notably, incremental costs were mainly attributed to AKI, which accounted for 37.5% of all incremental costs; it increased by US $9,840 for each AKI event, and the total cost increase reached US $2,588,035. CONCLUSIONS: Procedure-related complications, particularly postprocedural AKI, were associated with higher costs in PCI. Further studies are required to evaluate prospectively whether the preventive strategy with a personalized risk stratification for AKI could save costs.

Barriers Associated With Door-to-Balloon Delay in Contemporary Japanese Practice.

BACKGROUND: Door-to-balloon (DTB) time ≤90 min is an important quality indicator in the management of ST-elevation myocardial infarction (STEMI), but a considerable number of patients still do not meet this goal, particularly in countries outside the USA and Europe.Methods and Results:We analyzed 2,428 STEMI patients who underwent primary PCI ≤12 h of symptom onset who were registered in an ongoing prospective multicenter database (JCD-KiCS registry), between 2008 and 2013. We analyzed both the time trend in DTB time within this cohort in the registry, and independent predictors of delayed DTB time >90 min. Median DTB time was 90 min (IQR, 68-115 min) during the study period and there were no significant changes with year. Predictors for delay in DTB time included peripheral artery disease, prior revascularization, off-hour arrival, age >75 years, heart failure at arrival, and use of IABP or VA-ECMO. Notably, high-volume PCI-capable institutions (PCI ≥200/year) were more adept at achieving shorter DTB time compared with low-volume institutions (PCI <200/year). CONCLUSIONS: Half of the present STEMI patients did not achieve DTB time ≤90 min. Targeting the elderly and patients with multiple comorbidities, and PCI performed in off-hours may aid in its improvement.

[Skeletal muscle stem cell.]

Adult skeletal muscle has its own stem cell population known as satellite cells. After muscle injury, quiescent satellite cells are activated and then proliferate and differentiate into mature skeletal muscle to ensure that muscle function is recovered. In our screen for myocyte differentiation-promoting factors, we noted markedly elevated expression of granulocyte-colony stimulating factor receptor(G-CSFR, encoded by csf3r)in the skeletal muscle developing area. Furthermore, G-CSFR was transiently expressed in regenerating myocytes of adult injured skeletal muscle, and extrinsic G-CSF supported short-term and long-term muscle regeneration in mouse model of skeletal muscle injury.

HTRA1 (high temperature requirement A serine peptidase 1) gene is transcriptionally regulated by insertion/deletion nucleotides located at the 3' end of the ARMS2 (age-related maculopathy susceptibility 2) gene in patients with age-related macular degeneration.

Dry age-related macular degeneration (AMD) accounts for over 85% of AMD cases in the United States, whereas Japanese AMD patients predominantly progress to wet AMD or polypoidal choroidal vasculopathy. Recent genome-wide association studies have revealed a strong association between AMD and an insertion/deletion sequence between the ARMS2 (age-related maculopathy susceptibility 2) and HTRA1 (high temperature requirement A serine peptidase 1) genes. Transcription regulator activity was localized in mouse retinas using heterozygous HtrA1 knock-out mice in which HtrA1 exon 1 was replaced with ß-galactosidase cDNA, thereby resulting in dominant expression of the photoreceptors. The insertion/deletion sequence significantly induced HTRA1 transcription regulator activity in photoreceptor cell lines but not in retinal pigmented epithelium or other cell types. A deletion construct of the HTRA1 regulatory region indicated that potential transcriptional suppressors and activators surround the insertion/deletion sequence. Ten double-stranded DNA probes for this region were designed, three of which interacted with nuclear extracts from 661W cells in EMSA. Liquid chromatography-mass spectrometry (LC-MS/MS) of these EMSA bands subsequently identified a protein that bound the insertion/deletion sequence, LYRIC (lysine-rich CEACAM1 co-isolated) protein. In addition, induced pluripotent stem cells from wet AMD patients carrying the insertion/deletion sequence showed significant up-regulation of the HTRA1 transcript compared with controls. These data suggest that the insertion/deletion sequence alters the suppressor and activator cis-elements of HTRA1 and triggers sustained up-regulation of HTRA1. These results are consistent with a transgenic mouse model that ubiquitously overexpresses HtrA1 and exhibits characteristics similar to those of wet AMD patients.