Bayesian approach enabled objective comparison of multiple human iPSC-derived Cardiomyocytes' Proarrhythmia sensitivities.

The one-size-fits-all approach has been the mainstream in medicine, and the well-defined standards support the development of safe and effective therapies for many years. Advancing technologies, however, enabled precision medicine to treat a targeted patient population (e.g., HER2+ cancer). In safety pharmacology, computational population modeling has been successfully applied in virtual clinical trials to predict drug-induced proarrhythmia risks against a wide range of pseudo cohorts. In the meantime, population modeling in safety pharmacology experiments has been challenging. Here, we used five commercially available human iPSC-derived cardiomyocytes growing in 384-well plates and analyzed the effects of ten potential proarrhythmic compounds with four concentrations on their calcium transients (CaTs). All the cell lines exhibited an expected elongation or shortening of calcium transient duration with various degrees. Depending on compounds inhibiting several ion channels, such as hERG, peak and late sodium and L-type calcium or IKs channels, some of the cell lines exhibited irregular, discontinuous beating that was not predicted by computational simulations. To analyze the shapes of CaTs and irregularities of beat patterns comprehensively, we defined six parameters to characterize compound-induced CaT waveform changes, successfully visualizing the similarities and differences in compound-induced proarrhythmic sensitivities of different cell lines. We applied Bayesian statistics to predict sample populations based on experimental data to overcome the limited number of experimental replicates in high-throughput assays. This process facilitated the principal component analysis to classify compound-induced sensitivities of cell lines objectively. Finally, the association of sensitivities in compound-induced changes between phenotypic parameters and ion channel inhibitions measured using patch clamp recording was analyzed. Successful ranking of compound-induced sensitivity of cell lines was in lined with visual inspection of raw data.

Isolation of vapB-positive Rhodococcus equi from submaxillary lymph nodes with or without granulomatous lesions in growing-finishing pigs in Japan.

To investigate the etiological role of vapB-positive Rhodococcus equi in pigs, R. equi was isolated from the submaxillary lymph nodes with or without macroscopically detectable lesions of apparently healthy growing-finishing pigs at a slaughterhouse in Toyama Prefecture, Japan. R. equi was isolated from 57 (24.6%) of 232 pigs with macroscopically detectable lymph node lesions, and 56 (98.2%) of the 57 isolates were vapB-positive. R. equi was isolated from 10 (2.4%) of 420 pigs without lymph node lesions, and six (60%) of the 10 isolates were vapB-positive. Plasmid DNA was isolated from the 62 vapB-positive isolates and digested with EcoRI and NsiI to obtain the plasmid profile. Fifty-two (83.9%), three (4.8%), and four (6.5%) isolates contained pVAPB subtypes 1, 2, and 3, respectively, while the remaining three isolates were of pVAPB subtypes 9, 13, and 14, respectively. Twelve specimens from lymph nodes with macroscopically detectable lesions were randomly selected for histopathological staining. Granulomatous lesions resembling tuberculosis were found in 11 of the 12 specimens, and the remaining specimen showed typical foci of malakoplakia in the lymph node. The isolation rates of R. equi and vapB-positive R. equi from lymph nodes with macroscopically detectable lesions were significantly higher (P<0.05) than those of lymph nodes without lesions, suggesting an etiologic association between vapB-positive R. equi and macroscopically detectable granulomatous lesions in porcine submaxillary lymph nodes. Previous reports on the prevalence of vapB-positive R. equi in pigs are reviewed and discussed.

Safety evaluation of immediate breast reconstruction for locally advanced breast cancer in Japanese patients.

BACKGROUND: While breast reconstruction often improves the quality of life of patients with locally advanced breast cancer, there is still no consensus on its safety. This retrospective report aimed to verify the safety of immediate breast reconstruction for locally advanced breast cancer. METHODS: We retrospectively analyzed 500 breast cancer surgeries performed between January 2005 and December 2019 at our hospital, including 120 immediate breast reconstructions. The following five items were analyzed: the patients' choice of reconstruction method, rate of chemotherapy and radiotherapy, surgical margin positivity rate, complications associated with surgery, overall survival rate, and breast cancer-free survival rate. RESULTS: Sixty-three of the 120 patients underwent autologous breast reconstruction. Of those who underwent reconstruction surgery, 95.8% received chemotherapy and 78.3% underwent post-mastectomy radiation therapy. Reconstruction failed in 8 cases with tissue expander and in 1 case with free TRAM flap. Breast reconstruction surgery was not a factor in delaying adjuvant therapy, but complications requiring intervention tended to increase the duration of adjuvant therapy. There was no statistically significant difference in the rate of surgical margin positivity, overall survival rate, or breast cancer-free survival rate. CONCLUSIONS: Although complications associated with reconstructive surgery occurred, appropriate intervention prevented delays in breast cancer treatment, and the complications did not negatively affect the overall or breast cancer-free survival rates. Our study found no evidence to avoid primary breast reconstruction in patients with locally advanced breast cancer.

Germline variant of BRCA1 c.5332G>A has clinical features of hereditary breast and ovarian cancer syndrome.

The proband was a 39-year-old Japanese woman with stage I triple negative breast cancer. Germline BRCA1 and BRCA2 genetic testing revealed the presence of a BRCA1 c.5332G>A (p.Asp1778Asn) variant classified as a VUS in the heterozygous state. She underwent curative surgery and adjuvant chemotherapy for her TNBC, but no intensive follow-up or risk-reducing surgery was performed in contrast to normal practice in a patient with hereditary breast and ovarian cancer syndrome. At postoperative 2 years 6 months, elevation of CA15-3 led to the diagnosis of Stage III high-grade serous ovarian cancer. Studies and information in public databases at the time of the patient's genetic testing showed only VUS results for c.5332G>A; within the next few years, one pathogenic and one likely pathogenic result were confirmed. Thus, according to a joint consensus recommendation of the ACMG/AMP, c.5332G>A is considered 'likely pathogenic'. The public database should be checked regularly for VUS results, and practical management should be considered if reliable likely pathogenic or pathogenic reports were added.

Short- and long-term outcomes of immediate breast reconstruction surgery after neoadjuvant chemotherapy.

PURPOSE: Immediate breast reconstruction (IBR) is a standard option for breast cancer patients, although its utility in patients with advanced breast cancer requiring neoadjuvant chemotherapy (NAC) is debatable. We assessed the short-term complications and long-term prognosis of IBR after NAC. METHODS: We retrospectively analyzed 1135 patients with IBR and/or NAC between 2010 and 2018, 43 of whom underwent IBR after NAC. RESULTS: Twenty-five patients underwent reconstruction with a tissue expander (TE) followed by silicon breast implantation, 5 with a latissimus dorsi muscle transfer flap, and 13 with a deep inferior epigastric perforator flap. Complete surgical resection with a free margin confirmed by a pathological assessment was achieved in all patients. The evaluation of the short-term complications indicated no cases of total flap necrosis, two cases of partial flap necrosis, and one case of wound infection. Only one case required postponement of subsequent therapy due to partial flap necrosis. A long-term evaluation indicated no local recurrence, although distant metastasis was observed in 4 cases, 3 patients died, and TE removal after post-mastectomy radiotherapy (PMRT) was performed in 2 of 11 TE cases. CONCLUSION: IBR may be a viable option in patients with advanced breast cancer who achieve complete surgical resection after NAC.

Metastasis of breast cancer to liver through direct lymphatic drainage: a case report.

Breast cancer liver metastasis (BCLM) is considered to occur by hematogenous spread of primary breast cancer cells. We herein present a case of lymphatic BCLM that was confirmed by preoperative imaging for sentinel lymph node biopsy (SLNB). A woman in her early 70s was diagnosed with clinical stage T2N0M0 invasive lobular cancer of the left breast. She underwent mastectomy with SLNB. Preoperative lymphoscintigraphy showed intense accumulation of isotope in the upper abdomen, corresponding to segment IV of the liver on single-photon emission computed tomography/computed tomography (SPECT/CT). However, no abnormalities were detected on magnetic resonance imaging. At 2.5 years postoperatively, the patient's serum CA15-3 concentration was elevated, and positron emission tomography/computed tomography (PET/CT) showed a solitary liver metastasis. The PET/CT findings were similar to the SPECT/CT findings obtained 2.5 years earlier, indicating that the BCLM had developed lymphatically. To the best of our knowledge, this is the first case report of lymphatic BCLM proven by imaging examination.

Safety and Effectiveness of Areola-sparing Mastectomy for Breast Cancer With Intraductal Lesions.

BACKGROUND/AIM: Areola-sparing mastectomy (ASM), a conservative mastectomy with nipple hollowing, can be applied to intraductal breast cancer with a tumour-nipple-areola complex (NAC) distance of ≤2 cm. Here, we evaluated the safety and effectiveness of ASM. PATIENTS AND METHODS: We retrospectively reviewed the surgical outcomes of 61 patients (64 breasts) who underwent ASM between 2016 and 2020. RESULTS: Of the 64 breasts, 33 (51.6%) underwent ASM because the tumour-NAC distance on preoperative magnetic resonance imaging was ≤2 cm. Two patients had positive excisional margins but these were at the posterior areola surface therefore additional resection was possible. Over a median postoperative observation period of 16 months (range=3-52 months), one patient developed chest wall recurrence that was resected and did not recur again. CONCLUSION: For breast cancer with an extensive intraductal component, ASM is a good alternative to nipple-sparing mastectomy because it allows safe resection while maintaining aesthetics.

High-Throughput Drug Screening System Based on Human Induced Pluripotent Stem Cell-Derived Atrial Myocytes ∼ A Novel Platform to Detect Cardiac Toxicity for Atrial Arrhythmias.

Evaluation of proarrhythmic properties is critical for drug discovery. In particular, QT prolongation in electrocardiograms has been utilized as a surrogate marker in many evaluation systems to assess the risk of torsade de pointes and lethal ventricular arrhythmia. Recently, new evaluation systems based on human iPS cell-derived cardiomyocytes have been established. On the other hand, in clinical situations, it has been reported that the incidence of atrial arrhythmias such as atrial fibrillation has been increasing every year, with the prediction of a persistent increase in the near future. As to the increased incidence of atrial arrhythmias, in addition to the increased population of geriatric patients, a wide variety of drug treatments may be related, as an experimental method to detect drug-induced atrial arrhythmia has not been established so far. In the present study, we characterized the atrial-like cardiomyocytes derived from human induced pluripotent stem cells and examined their potential for the evaluation of drug-induced atrial arrhythmia. Atrial-like cardiomyocytes were induced by adding retinoic acid (RA) during the process of myocardial differentiation, and their characteristics were compared to those of RA-free cardiomyocytes. Using gene expression and membrane potential analysis, it was confirmed that the cells with or without RA treatment have atrial or ventricular like cardiomyocytes, respectively. Using the ultra-rapid activating delayed rectifier potassium current (IKur) channel inhibitor, which is specific to atrial cardiomyocytes, Pulse width duration (PWD) 30cF prolongation was confirmed only in atrial-like cardiomyocytes. In addition, ventricular like cardiomyocytes exhibited an early after depolarization by treatment with rapidly activating delayed rectifier potassium current (IKr) channel inhibitor, which induces ventricular arrhythmia in clinical situations. Here, we have established a high-throughput drug evaluation system using human iPS cell-derived atrial-like cardiomyocytes. Based on the obtained data, the system might be a valuable platform to detect potential risks for drug-induced atrial arrhythmias.

[Availability of a novel cardiotoxicity evaluation system using human induced pluripotent stem cell-derived atrial-like myocytes].

It is reported that the incidence of atrial arrhythmias has been increasing year by year and it might increase from now on. Although not only aging but pharmaceutical drug treatments might relate to atrial arrhythmias, experimental method to detect drug-induced atrial arrhythmias has not been established so far. Therefore, we induced differentiation of atrial-like cardiomyocytes from human induced pluripotent stem (iPS) cell, and clarified their characteristics and verified their dug responsiveness. Atrial-like cardiomyocytes were induced by adding retinoic acid (RA) during the process of myocardial differentiation, and their character was compared to RA-untreated cardiomyocytes. In gene expression and membrane potential analysis, it was confirmed that the cells with or without RA treatment have the characters of atrial or ventricular like cardiomyocytes, respectively. In addition, it was also confirmed that atrial-like cardiomyocytes induced reentry-like conduction disorder, which is atrial arrhythmias. Furthermore, as a result of examining the responsiveness of various ion channel inhibitors using these cells, the inhibition of ultra-rapid delayed rectifier potassium current (IKur) specifically existed in atrial muscle induced prolongation of PWD30cF (membrane potential duration at 30% depolarization corrected by Fridericia formula) only in atrial-like cardiomyocytes. In addition, ventricular-like cardiomyocytes alone exhibited an early after depolarization by treatment of rapid rectifier potassium current (IKr) inhibitor which induced ventricular arrhythmia in clinical situation. Based on above evidences, current evaluation systems using human iPS cell-derived atrial-like cardiomyocytes might be a valuable tool for drug-induced atrial arrhythmias.

[A Case Report on the Effectiveness of Olaparib in a Patient with Recurrent Breast Cancer with Human Immunodeficiency Virus Infection].

A 43 -year-old woman presented to the hospital with a right breast tumor. She had been treated for human immunodeficiency virus(HIV)infection for 5 years. After being diagnosed with right breast cancer, she underwent total mastectomy and sentinel lymph node biopsy, which indicated T2N1M0 triple-negative breast cancer. She received doxorubicin and cyclophosphamide( AC)followed by docetaxel(AC-T)as postoperative adjuvant chemotherapy. However, 14 months after the adjuvant chemotherapy finished, distant metastasis occurred in the brain, lung, and mediastinum lymph nodes. Treatment for relapse was initiated, with whole brain radiotherapy followed by paclitaxel plus bevacizumab combination therapy(PB); however, new metastatic lesions were found in the bone, liver, and mediastinum lymph node after 2 courses of PB. Given the risk of hereditary breast and ovarian cancer syndrome, a BRCAgene test was performed when the patient received radiotherapy for left recurrent laryngeal nerve paralysis caused by mediastinal lymph nodes; this showed a result positive for a deleterious mutation in BRCA1. Thus, treatment with olaparib, a poly(ADP-ribose)polymerase(PARP)inhibitor, was started. Metastatic lesions, including barky growth, in the liver metastasis were well controlled, as confirmed by CT imaging 4 months after the start of olaparib.

Application of the Z1071 criteria: classification of axillary lymph nodes on ultrasound after neoadjuvant chemotherapy in initially node-positive breast cancer.

PURPOSE: The American College of Surgeons Oncology Group (ACOSOG) Z1071 trial assessed the accuracy of sentinel lymph node biopsies in clinically node-positive patients who underwent neoadjuvant chemotherapy (NAC). Axillary ultrasound (US) images after NAC were reviewed, and the accuracy of classifying nodes into six types according to the ACOSOG Z1071 trial was determined. METHODS: This study included 69 patients who underwent NAC followed by curative surgery for breast cancer including axillary lymph node dissection between January 2010 and July 2019. All patients were pathologically confirmed as being initially node positive. Lymph nodes were retrospectively classified into one of six types based on the appearance of the nodal cortex and hilum. Types I and II were classified as having normal nodal morphology, whereas types III, IV, V, and VI were classified as having suspicious nodal morphology. These node types on US images after NAC were compared between patients with an axillary complete response (Ax-pCR) and those with residual metastatic lymph nodes (Ax-non-pCR) using Chi-square tests. RESULTS: Twenty-four (35%) of the 69 patients achieved Ax-pCR. Patients with nodes classified as type I or II were more likely to achieve Ax-pCR (83% vs. 36%, p = 0. 0002). CONCLUSION: The classification of six node types was associated with nodal status.

Predictive factors of an axillary pathological complete response of node-positive breast cancer to neoadjuvant chemotherapy.

PURPOSE: The present study aimed to identify the predictive factors of an axillary pathological complete response (Ax-pCR) in patients with node-positive breast cancer who underwent neoadjuvant chemotherapy (NAC). METHODS: The present study included 219 patients who underwent NAC followed by curative surgery, including axillary lymph node dissection (ALND), for 221 breast cancers between January 2010 and April 2018. All patients were clinically and/or pathologically confirmed to be node-positive at the initial diagnosis. The predictive factors of Ax-pCR were analyzed using a chi-square test and multivariate logistic regression models. RESULTS: Ninety-five patients (43%) achieved Ax-pCR after NAC. The odds of achieving Ax-pCR were significantly improved when tumors were high grade (odds ratio [OR] 2.20, 95% confidence interval [CI] 1.00-4.84), estrogen receptor (ER) negative (OR 2.65 95% CI 1.23-5.70), ycN0 on ultrasound (US) imaging (OR 3.89, 95% CI 1.90-7.97), and showed a clinical complete response (CR) at the primary site after NAC (OR 4.22, 95% CI 1.59-11.27). CONCLUSIONS: Ax-pCR was more likely to be achieved in patients who were diagnosed with ER-negative and high-grade breast cancer and those with ycN0 and clinical CR at the primary site after NAC than among others. Among these patients, those with initially cN1/N2 might be good candidates for a deescalated treatment strategy after NAC.

Geometrical Patterning and Constituent Cell Heterogeneity Facilitate Electrical Conduction Disturbances in a Human Induced Pluripotent Stem Cell-Based Platform: An In vitro Disease Model of Atrial Arrhythmias.

Ectopic foci from pulmonary veins (PVs) comprise the main trigger associated with the initiation of atrial fibrillation (AF). An abrupt anatomical narrow-to-wide transition, modeled as in vitro geometrical patterning with similar configuration in the present study, is located at the junction of PVs and the left atrium (LA). Complex cellular composition, i.e., constituent cell heterogeneity, is also observed in PVs and the PVs-LA junction. High frequency triggers accompanied with anatomical irregularity and constituent cell heterogeneity provoke impaired conduction, a prerequisite for AF genesis. However, few experiments investigating the effects of these factors on electrophysiological properties using human-based cardiomyocytes (CMs) with atrial properties have been reported. The aim of the current study was to estimate whether geometrical patterning and constituent cell heterogeneity under high frequency stimuli undergo conduction disturbance utilizing an in vitro two-dimensional (2D) monolayer preparation consisting of atrial-like CMs derived from human induced pluripotent stem cells (hiPSCs) and atrial fibroblasts (Fbs). We induced hiPSCs into atrial-like CMs using a directed cardiac differentiation protocol with the addition of all-trans retinoic acid (ATRA). The atrial-like hiPSC-derived CMs (hiPSC-CMs) and atrial Fbs were transferred in defined ratios (CMs/Fbs: 100%/0% or 70%/30%) on manually fabricated plates with or without geometrical patterning imitating the PVs-LA junction. High frequency field stimulation emulating repetitive ectopic foci originated in PVs were delivered, and the electrical propagation was assessed by optical mapping. We generated high purity CMs with or without the ATRA application. ATRA-treated hiPSC-CMs exhibited significantly higher atrial-specific properties by immunofluorescence staining, gene expression patterns, and optical action potential parameters than those of ATRA-untreated hiPSC-CMs. Electrical stimuli at a higher frequency preferentially induced impaired electrical conduction on atrial-like hiPSC-CMs monolayer preparations with an abrupt geometrical transition than on those with uniform geometry. Additionally, the application of human atrial Fbs to the geometrically patterned atrial-like hiPSC-CMs tended to further deteriorate the integrity of electrical conduction compared with those using the atrial-like hiPSC-CM alone preparations. Thus, geometrical narrow-to-wide patterning under high frequency stimuli preferentially jeopardized electrical conduction within in vitro atrial-like hiPSC-CM monolayers. Constituent cell heterogeneity represented by atrial Fbs also contributed to the further deterioration of conduction stability.

[Toxicity of Palbociclib in Patients Aged 70 Years and Older with Metastatic Breast Cancer].

We aimed to examine palbociclib toxicity in patients aged 70 years and older with metastatic breast cancer(MBC). From December 2017 to August 2018, 32 patients with estrogen receptor(ER)-positive, human epidermal growth factor receptor 2(HER2)-negative MBC were included in this study. The most common adverse event(AE)observed was neutropenia, and comparative rates of grade 3 or 4 AE were identified in the groups of patients aged ≥70 years(n=11)and <70 years(n=21) (91% vs 81%). Febrile neutropenia occurred in one patient. Although dose interruption rate was higher in the older group (≥70 years of age)than in the younger group(<70 years of age)(100% vs 86%, respectively), reduction rates were similar between the two groups(64% vs 62%, respectively). Palbociclib was well-tolerated in Japanese older(≥70 years of age) MBC patients.

Ultrasound-guided fine-needle aspiration of axillary lymph nodes in breast cancer: Diagnostic accuracy and role in surgical management.

BACKGROUND: The objective of this study was to evaluate the accuracy of fine needle aspiration cytology (FNAC) of axillary lymph nodes (LN) in breast cancer, to compare the results of FNAC and pathological examination, and to distinguish patients with 1 to 2 metastatic LNs from those with ≥3 metastatic LNs in patients with FNAC-positive patients. PATIENTS AND METHODS: This study included 198 breasts of 196 patients with breast cancer who underwent FNAC and surgery for the primary and axilla without neoadjuvant chemotherapy from January 2010 to August 2016. Axillary nodal status was assessed by ultrasound (US), and whether FNAC-positive had three or more suspicious LNs on US imaging was examined. RESULTS: The results of FNAC were positive in 75 (38%), negative in 97 (49%), suspicious in 2 (1%), indeterminate in 5 (2.5%), and insufficient in 19 patients (9.5%). FNAC sensitivity, specificity, positive predictive value, and negative predictive value were 62.6%, 100%, 100%, and 62.0%, respectively. Whereas 53% (18/34) of patients with false-negative FNAC had one metastatic LN on final pathology, 61% (47/77) patients who were FNAC-positive had three or more metastatic LNs. In the FNAC-positive patients, all patients had ≥3 metastatic LNs if they had ≥3 suspicious LNs on US imaging. CONCLUSION: Patients with positive cytology were more likely to have ≥3 positive LNs compared to false-negative cytology patients. Patients with ≥3 abnormal LNs on US and positive FNAC might require axillary dissection.

Increased susceptibility to oxidative stress-induced toxicological evaluation by genetically modified nrf2a-deficient zebrafish.

INTRODUCTION: Oxidative stress plays an important role in drug-induced toxicity. Oxidative stress-mediated toxicities can be detected using conventional animal models but their sensitivity is insufficient, and novel models to improve susceptibility to oxidative stress have been researched. In recent years, gene targeting methods in zebrafish have been developed, making it possible to generate homozygous null mutants. In this study, we established zebrafish deficient in the nuclear factor erythroid 2-related factor 2a (nrf2a), a key antioxidant-responsive gene, and its potential to detect oxidative stress-mediated toxicity was examined. METHODS: Nrf2a-deficient zebrafish were generated using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 technique. The loss of nrf2a function was confirmed by the tolerability to hydrogen peroxide and hydrogen peroxide-induced gene expression profiles being related to antioxidant response element (ARE)-dependent signaling. Subsequently, vulnerability of nrf2a-deficient zebrafish to acetaminophen (APAP)- or doxorubicin (DOX)-induced toxicity was investigated. RESULTS: Nrf2a-deficient zebrafish showed higher mortality than wild type accompanied by less induction of ARE-dependent genes with hydrogen peroxide treatment. Subsequently, this model showed increased severity and incidence of APAP-induced hepatotoxicity or DOX-induced cardiotoxicity than wild type. DISCUSSION: Our results demonstrated that anti-oxidative response might not fully function in this model, and resulted in higher sensitivity to drug-induced oxidative stress. Our data support the usefulness of nrf2a-deficient model as a tool for evaluation of oxidative stress-related toxicity in drug discovery research.

Usefulness of cardiotoxicity assessment using calcium transient in human induced pluripotent stem cell-derived cardiomyocytes.

Monitoring dramatic changes in intracellular calcium ion levels during cardiac contraction and relaxation, known as calcium transient, in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) would be an attractive strategy for assessing compounds on cardiac contractility. In addition, as arrhythmogenic compounds are known to induce characteristic waveform changes in hiPSC-CMs, it is expected that calcium transient would allow evaluation of not only compound-induced effects on cardiac contractility, but also compound arrhythmogenic potential. Using a combination of calcium transient in hiPSC-CMs and a fast kinetic fluorescence imaging detection system, we examined in this study changes in calcium transient waveforms induced by a series of 17 compounds that include positive/negative inotropic agents as well as cardiac ion channel activators/inhibitors. We found that all positive inotropic compounds induced an increase in peak frequency and/or peak amplitude. The effects of a negative inotropic compound could clearly be detected in the presence of a ß-adrenergic receptor agonist. Furthermore, most arrhythmogenic compounds raised the ratio of peak decay time to peak rise time (D/R ratio) in calcium transient waveforms. Compound concentrations at which these parameters exceeded cutoff values correlated well with systemic exposure levels at which arrhythmias were reported to be evoked. In conclusion, we believe that peak analysis of calcium transient and determination of D/R ratio are reliable methods for assessing compounds' cardiac contractility and arrhythmogenic potential, respectively. Using these approaches would allow selection of compounds with low cardiotoxic potential at the early stage of drug discovery.

CSAHi study-2: Validation of multi-electrode array systems (MEA60/2100) for prediction of drug-induced proarrhythmia using human iPS cell-derived cardiomyocytes: Assessment of reference compounds and comparison with non-clinical studies and clinical information.

With the aim of reconsidering ICH S7B and E14 guidelines, a new in vitro assay system has been subjected to worldwide validation to establish a better prediction platform for potential drug-induced QT prolongation and the consequent TdP in clinical practice. In Japan, CSAHi HEART team has been working on hiPS-CMs in the MEA (hiPS-CMs/MEA) under a standardized protocol and found no inter-facility or lot-to-lot variability for proarrhythmic risk assessment of 7 reference compounds. In this study, we evaluated the responses of hiPS-CMs/MEA to another 31 reference compounds associated with cardiac toxicities, and gene expression to further clarify the electrophysiological characteristics over the course of culture period. The hiPS-CMs/MEA assay accurately predicted reference compounds potential for arrhythmogenesis, and yielded results that showed better correlation with target concentrations of QTc prolongation or TdP in clinical setting than other current in vitro and in vivo assays. Gene expression analyses revealed consistent profiles in all samples within and among the testing facilities. This report would provide CiPA with informative guidance on the use of the hiPS-CMs/MEA assay, and promote the establishment of a new paradigm, beyond conventional in vitro and in vivo assays for cardiac safety assessment of new drugs.

CSAHi study: Validation of multi-electrode array systems (MEA60/2100) for prediction of drug-induced proarrhythmia using human iPS cell-derived cardiomyocytes -assessment of inter-facility and cells lot-to-lot-variability.

In vitro screening of hERG channels are recommended under ICH S7B guidelines to predict drug-induced QT prolongation and Torsade de Pointes (TdP), whereas proarrhythmia is known to be evoked by blockage of other ion channels involved in cardiac contraction and compensation mechanisms. A consortium for drug safety assessment using human iPS cells-derived cardiomyocytes (hiPS-CMs), CSAHi, has been organized to establish a novel in vitro test system that would enable better prediction of drug-induced proarrhythmia and QT prolongation. Here we report the inter-facility and cells lot-to-lot variability evaluated with FPDc (corrected field potential duration), FPDc10 (10% FPDc change concentration), beat rate and incidence of arrhythmia-like waveform or arrest on hiPS-CMs in a multi-electrode array system. Arrhythmia-like waveforms were evident for all test compounds, other than chromanol 293B, that evoked FPDc prolongation in this system and are reported to induce TdP in clinical practice. There was no apparent cells lot-to-lot variability, while inter-facility variabilities were limited within ranges from 3.9- to 20-folds for FPDc10 and about 10-folds for the minimum concentration inducing arrhythmia-like waveform or arrests. In conclusion, the new assay model reported here would enable accurate prediction of a drug potential for proarrhythmia.

Invasive papillary carcinoma treated with neoadjuvant endocrine therapy in which pathological complete response was achieved.

BACKGROUND: Invasive papillary carcinoma is a rare type of invasive ductal carcinoma. Neoadjuvant endocrine therapy is now considered as an optional therapy for postmenopausal women with hormone receptor-positive breast cancers, including invasive papillary carcinoma. CASE PRESENTATION: We discuss the case of an 83-year-old postmenopausal Japanese female with hormone receptor-positive invasive papillary carcinoma who started treatment with an aromatase inhibitor and achieved pathological complete response after 12 months of endocrine treatment. CONCLUSION: Appropriate drugs and durations of neoadjuvant endocrine treatment have yet to be established. Continuing therapy with an aromatase inhibitor until the best clinical response is achieved may represent one of the best strategies in neoadjuvant endocrine therapy.