Functional characterization of drug responses in induced pluripotent stem cell-derived cardiomyocytes from a short QT syndrome type 5 patient

Funding Acknowledgements

Type of funding sources: Other. Main funding source(s): ETH Zurich Personalized Health and Related Technologies; German Centre for Cardiovascular Research

Introduction

Short QT syndrome (SQTS) and Brugada syndrome (BrS) are rare channelopathies causing sudden cardiac death (SCD). There are only few investigations of effective therapies of SQTS and BrS linked to CACNB2 variants. Since treatment data of SQTS are sparse, we studied drug responses of induced pluripotent stem cell-derived cardiomyocyte (iPSC-CM) 2D cultures carrying a mutation in the CACNB2 gene from a SQTS type 5 (SQT5) patient with an established phenotype. We used high-density microelectrode arrays (HD-MEAs), patch clamp, and calcium-transient imaging.

Purpose

To investigate the electrophysiological responses of SQT5 patient-derived iPSC-CMs upon exposure to antiarrhythmic drugs.

Methods

Human iPSCs, derived from a SQT5 patient and a healthy donor, were cultured and differentiated into cardiomyocytes by temporal modulation of the Wnt signaling. For electrophysiological measurements, spontaneously beating cardiomyocytes at day 40-60 were dissociated and plated a) on petri dishes for patch clamp and calcium-transient measurements and b) directly on HD-MEAs. Antiarrhythmic drugs, including sotalol, quinidine, and flecainide, were dosed to the cells after plating as soon as stable activity levels were measured. After baseline measurements, drug doses were sequentially increased from low to high concentrations.

Results

We observed spontaneous and synchronous beating of SQT5 patient- and healthy donor-derived iPSC-CMs. Quinidine, which is known to be effective for treatment of SQTS with possible differences for subtypes, prolonged field-potential duration (FPD) and action-potential duration in SQT5 patient-derived iPSC-CMs. Sotalol slightly increased FPD at 30µM as measured with HD-MEAs, whereas action-potential duration (APD) measured through patch clamp did not exhibit a notable effect at 30 µM. APD became shorter at higher concentrations, which is in line with clinical data of SQTS patients. HD-MEA measurements showed that flecainide shortened the FPD of SQT5 patient-derived CMs at 20µM. For healthy donor-derived iPSC-CMs, quinidine, sotalol, and flecainide prolonged FPDs in HD-MEA measurements. Using calcium-transient imaging, quinidine showed a slight antiarrhythmic effect, whereas sotalol did not have antiarrhythmic effects.

Conclusion

We used HD-MEAs, patch clamp, and calcium-transient imaging to analyze electrophysiological responses of SQT5 patient-derived iPSC-CMs upon dosage of antiarrhythmic drugs. Our preliminary results show that quinidine - but not flecainide - could prolong the repolarization duration in SQT5 patient-derived iPSC-CMs.

Influence of patient and tumor characteristics on early therapy persistence with letrozole in postmenopausal women with early breast cancer: results of the prospective Evaluate-TM study with 3941 patients

Background

Patients' compliance and persistence with endocrine treatment has a significant effect on the prognosis in early breast cancer (EBC). The purpose of this analysis was to identify possible reasons for non-persistence, defined as premature cessation of therapy, on the basis of patient and tumor characteristics in individuals receiving adjuvant treatment with letrozole.

Patients and methods

The EvAluate-TM study is a prospective, multicenter, noninterventional study in which treatment with the aromatase inhibitor letrozole was evaluated in postmenopausal women with hormone receptor-positive EBC in the early therapy phase. Treatment persistence was evaluated at two pre-specified study visits after 6 and 12 months. As a measure of early therapy persistence the time from the start to the end of treatment (TTEOT) was analyzed. Cox regression analyses were carried out to identify patient characteristics and tumor characteristics predicting TTEOT.

Results

Out of the total population of 3941 patients with EBC, 540 (13.7%) events involving treatment cessation unrelated to disease progression were observed. This was due to drug-related toxicity in the majority of cases (73.5%). Persistence rates were 92.2%, 86.9%, and 86.3% after 6, 12, and 15 months, respectively. The main factors influencing premature treatment discontinuation were older age [hazard ratio (HR) 1.02/year], comorbidities (HR 1.06 per comorbidity), low body mass index, and lower tumor grade (HR 0.85 per grade unit).

Conclusion

These results support the view that older, multimorbid patients with low tumor grade and low body mass index are at the greatest risk for treatment discontinuation and might benefit from compliance and support programs.

Influence of side-effects on early therapy persistence with letrozole in post-menopausal patients with early breast cancer: Results of the prospective EvAluate-TM study

BACKGROUND

Endocrine treatment (ET) with an aromatase inhibitor (AI) is the treatment of choice in post-menopausal patients with hormone receptor-positive early breast cancer (EBC). However, adverse events (AEs) often lead to treatment discontinuation. This analysis aimed to identify side-effects that lead to patients failing to persist with letrozole treatment.

PATIENTS AND METHODS

Post-menopausal hormone receptor-positive EBC patients starting ET with letrozole were enroled in EvAluate-TM, a non-interventional study. Information regarding treatment compliance and persistence was gathered in months 6 and 12. Persistence was defined as the time from 30 d after the start to the end of treatment. The influence on persistence of musculoskeletal syndrome, menopausal disorder, sleep disorder and other AEs within the first 30 d was analysed using Cox regression analyses.

RESULTS

Among 3887 patients analysed, the persistence rate after 12 months was >85%. In all, 568 patients (14.6%) discontinued the treatment, 358 of whom (63.0%) did so only because of side-effects. The main AEs influencing persistence were musculoskeletal symptoms (hazard ratio [HR] 2.55; 95% confidence interval [CI], 1.90-3.42), sleep disorders (HR 1.95; 95% CI, 1.41-2.70) and other AEs (HR 2.03; 95% CI, 1.51-2.73). Menopausal disorder was not associated with non-persistence (HR 1.17; 95% CI, 0.74-1.84).

CONCLUSIONS

These results suggest that side-effects of AIs such as musculoskeletal syndrome and sleep disorder lead to ET discontinuation within the first treatment year in significant numbers of EBC patients. Compliance programmes adapted for subgroups that are at risk for early non-persistence might help to ensure the recommended therapy duration.

CLINICAL TRIALS NUMBER

CFEM345DDE19.

Antibiotic consumption after implementation of a procalcitonin-guided antimicrobial stewardship programme in surgical patients admitted to an intensive care unit: a retrospective before-and-after analysis

PURPOSE

To analyse antibiotic use density (AD)--World Health Organization defined daily doses/1,000 patient-days--before and after implementation of a local antimicrobial stewardship programme (ASP) in conjunction with a procalcitonin (PCT)-guided protocol in a surgical intensive care unit (ICU).

METHODS

In this retrospective observational study, data on 2,422 ICU patients between 2010 and 2012 were analysed. In 2011, an ASP in conjunction with a PCT protocol had been introduced into clinical practice. In a multivariate analysis, hospital mortality, length of stay (LOS) in hospital and ICU LOS were adjusted for effects from effective cost weight, gender, and age. AD and changes in the use of antibiotic classes were analysed.

RESULTS

AD decreased from 1,005.0 in 2010 to 791.9 in 2012 which is a total reduction of 21.2%. Consumption of aminoglycosides, cephalosporins and quinolones showed a marked reduction, whereas the use of penicillins did not change significantly. The multivariate models revealed no relevant changes in mortality rate, ICU LOS and hospital LOS.

CONCLUSIONS

Implementation of an ASP in conjunction with a PCT protocol in 2011 was associated with a marked decrease in total AD and led to a significant change in the spectrum of antibiotics. Clinical outcomes appeared to remain unchanged over the study period.

Evaluation of Therapy Management and Patient Compliance in Postmenopausal Patients with Hormone Receptor-positive Breast Cancer Receiving Letrozole Treatment: The EvaluateTM Study

Introduction: The EvaluateTM study (Evaluation of therapy management and patient compliance in postmenopausal hormone receptor-positive breast cancer patients receiving letrozole treatment) is a prospective, non-interventional study for the assessment of therapy management and compliance in the routine care of postmenopausal women with invasive hormone receptor-positive breast cancer receiving letrozole. The parameters for inclusion in the study are presented and discussed here. Material and Methods: Between January 2008 and December 2009 a total of 5045 patients in 310 study centers were recruited to the EvaluateTM study. Inclusion criteria were hormone receptor-positive breast cancer and adjuvant treatment or metastasis. 373 patients were excluded from the analysis for various reasons. Results: A total of 4420 patients receiving adjuvant treatment and 252 patients with metastasis receiving palliative treatment were included in the study. For 4181 patients receiving adjuvant treatment, treatment with the aromatase inhibitor letrozole commenced immediately after surgery (upfront). Two hundred patients had initially received tamoxifen and started aromatase inhibitor treatment with letrozole at 1-5 years after diagnosis (switch), und 39 patients only commenced letrozole treatment 5-10 years after diagnosis (extended endocrine therapy). Patient and tumor characteristics were within expected ranges, as were comorbidities and concurrent medication. Conclusion: The data from the EvaluateTM study will offer a good overview of therapy management in the routine care of postmenopausal women with hormone receptor-positive breast cancer. Planned analyses will look at therapy compliance and patient satisfaction with how information is conveyed and the contents of the conveyed information.

Production and separation of ''non-standard'' PET nuclides at a large cyclotron facility: the experiences at the Paul Scherrer Institute in Switzerland

Radioimmuno-positron emission tomography (PET) combined with radioimmunotherapy is attractive to assess tumor targeting and quantitate the radiation dose to tumor and normal tissues. For this purpose, PET radionuclides with adequate physical half-lives matching those of the targeting molecule (e.g. antibodies) are preferable. Copper-64 (T(1/2)=12.7 h, E(beta+max)=653 keV) and Zirconium-89 (T(1/2)=78.4 d, E(beta+max)=901 keV) are attractive isotopes for this purpose. The 72 MeV cyclotron at the Paul Scherrer Institute provides the infrastructure for the production of a wide variety of radionuclides for diagnostic and therapeutic purposes. (64)Cu and (89)Zr are currently evaluated at the Center for Radiopharmaceutical Science (CRS) of the Paul Scherrer Institute (PSI) in combination with the L1 cam targeting antibody chCE7 and various protein formats thereof. A second focus of the CRS is the radiolabeling of small, tumor targeting molecules with technetium. The PET isotope (94m)Tc offers potential alternative to its widely used (99m)Tc SPECT counterpart. In this report, the development, optimization and pitfalls of (64)Cu, (89)Zr and (94m)Tc production/separation are reported and discussed.

Some optimisation studies relevant to the production of high-purity 124I and 120gI at a small-sized cyclotron

Optimisation experiments on the production of the positron emitting radionuclides 124I(T(1/2) = 4.18d) and (120g)I (T(1/2) = 1.35 h) were carried out. The TeO(2)-target technology and dry distillation method of radioiodine separation were used. The removal of radioiodine was studied as a function of time and the loss of TeO(2) from the target as a function of oven temperature and time of distillation. A distillation time of 15 min at 750 degrees C was found to be ideal. Using a very pure source and comparing the intensities of the annihilation and X-ray radiation, a value of 22.0 +/- 0.5% for the beta(+) branching in 124I was obtained. Production of 124I was done using 200 mg/cm(2) targets of 99.8% enriched 124TeO(2) on Pt-backing, 16 MeV proton beam intensities of 10 microA, and irradiation times of about 8 h. The average yield of 124I at EOB was 470 MBq(12.7 mCi). At the time of application (about 70 h after EOB) the radionuclidic impurity 123I (T(1/2) = 13.2 h) was <1%. The levels of other impurities were negligible (126I < 0.0001%;125I = 0.01%). Special care was taken to determine the 125I impurity. For the production of (120g)I only a thin 30 mg target (on 0.5 cm(2) area) of 99.9% enriched 120TeO(2) was available. Irradiations were done with 16 MeV protons for 80 min at beam currents of 7 microA. The 120gI yield achieved at EOB was 700 MBq(19 mCi), and the only impurity detected was the isomeric state 120 mI(T(1/2) = 53 min) at a level of 4.0%. The radiochemical purity of both 124I and 120gI was checked via HPLC and TLC. The radioiodine collected in 0.02 M NaOH solution existed >98% as iodide. The amount of inactive Te found in radioiodine was <1 microg. High purity 124I and 120gI can thus be advantageously produced on a medium scale using the low-energy (p,n) reaction at a small-sized cyclotron.

Excitation functions of 125Te(p, xn)-reactions from their respective thresholds up to 100 MeV with special reference to the production of 124I

Excitation functions of the nuclear reactions 125Te(p, xn) (119,120m, 120g, 121,122,123,124,125)I were measured for the first time from their respective thresholds up to 100 MeV using the stacked-foil technique. Thin samples were prepared by electrolytic deposition of 98.3% enriched 125Te on Ti-backing. In addition to experimental studies, excitation functions were calculated by the modified hybrid model code ALICE-IPPE. The experimental and theoretical data generally showed good agreement. From the measured cross section data, integral yields of (123,124,125)I were calculated. The energy range Ep 21 --> 15 MeV appears to be very suitable for the production of the medically interesting radionuclide 124I (T(1/2) = 4.18 d; I(beta)+ = 25%). The thick target yield of 124I amounts to 81 MBq/microA h and the level of 125I-impurity to 0.9%. The 125Te(p,2n)124I reaction gives 124I yield about four times higher than the commonly used 124Te(p,n)124I and 124Te(d,2n)124I reactions. The proposed production energy range is too high for small cyclotrons but large quantities of 124I can be produced with medium-sized commercial machines.

Dynamic regulation of BDNF and NT-3 expression during visual system development

Recent studies have proposed roles for neurotrophins in the formation and plasticity of ocular dominance columns as well as in the regulation of dendritic arborization in visual cortex of higher mammals. To assess potential roles for neurotrophins in these processes, we have examined the developmental expression of BDNF and NT-3 mRNA in the cat's visual system using in situ hybridization. BDNF and NT-3 mRNAs are dynamically regulated in many CNS structures during embryonic and postnatal development, and both mRNAs undergo striking developmental changes in laminar specificity and levels of expression within primary visual cortex during the critical period for ocular dominance column formation. Within visual cortex, BDNF mRNA is found in neurons in deep cortical layers (5 and 6) prior to eye opening, and in both deep and superficial layers (2 and 3) shortly afterwards. Within layer 4, the target of thalamocortical axons, BDNF mRNA is low initially and rises to high levels by the end of the critical period for ocular dominance column formation. NT-3 mRNA is first detectable in small stellate neurons at the base of layer 4 (4c) after eye opening, and levels decrease near the end of the critical period. BDNF and NT-3 mRNAs can be detected in the lateral geniculate nucleus at birth, and levels peak during the critical period. In both structures, BDNF mRNA expression is maintained into adulthood, while NT-3 is undetectable in the adult. The presence and dynamic regulation of these neurotrophins in visual structures is consistent with suggested roles for both of these neurotrophins in axonal and dendritic remodeling known to accompany the formation of ocular dominance columns.

Excitation functions of 120Te(d,xn)121,120m,gI reactions from threshold up to 13.5 MeV: comparative studies on the production of 120gI

Excitation functions of the nuclear reactions 120Te(d,xn)121,120m,gI were measured for the first time from their respective thresholds up to 13.5 MeV. Thin samples prepared by electrolytic deposition of 99.0% enriched 120Te on Ti-backing were used. Integral yields of 121,120m,gI were calculated from the measured cross section data. A comparison of the 122Te(p,3n)-, 120Te(p,n)- and 120Te(d,2n)-processes for the production of 120gI is given. The 120Te(d,2n)-process is unsuitable for production purposes since the yield of 120gI is very low and the level of 121I impurity very high. The choice lies either on the 122Te(p,3n)- or the 120Te(p,n)-reaction and is governed by the available proton energy and the financial resources for procuring the enriched target material.

Nuclear model calculations on proton and deuteron induced reactions on 122Te and 120Te with particular reference to the formation of the isomeric states 120m,gI

Nuclear model calculations were performed on (p,xn) reactions on 122Te and 120Te, and (d,xn) reactions on 120Te. The computer code used (STAPRE) incorporates statistical and precompound models as well as nuclear structure effects. The total cross-sections of (p,xn) and (d,xn) processes leading to the formation of the radioisotopes 119I, 120gI, 121I and 122I are described well by the calculations. The isomeric cross-section, however, is rather difficult to calculate. The yield of the high spin isomer (120mI) depends on the type of reaction involved and increases with the increasing projectile energy. From an analysis of the energy dependence of the isomeric cross-section ratio, the excitation energy of 120mI was deduced to be 550+/-50 keV and its spin and parity as 4+. The experimental data reported earlier and the theoretical analysis presented in this work allow to define the optimum conditions for the production of the medically important beta+ emitter 120gI with enhanced confidence.

Blood pressure and self-concept among African-American adolescents

Differences in blood pressure among individuals of African ancestry living in the United States compared with those living in Africa suggest that the high prevalence of hypertension among African Americans may be due in part to environmental factors. There are a number of environmental models that attempt to account for the high rate of hypertension among African Americans. One model proposes that a strong African self-concept protects African-American adolescents from the hypertensive effects of social stress. This model was tested during a blood pressure survey of 333 adolescents in three urban Los Angeles high schools. African self-concept was assessed using a three-item scale. The average score for the three items was strongly related to systolic blood pressure among African-American male adolescents. After controlling for age, body mass index, and parent's education in regression analyses, the relation was reduced, but an effect remained. The model suggests that the hypertensive effects of the environment will operate unless the pathway from environmental stress to hypertension is blocked by a strong African-American self-concept.

Inhibition of ocular dominance column formation by infusion of NT-4/5 or BDNF

During the development of the visual system of higher mammals, axons from the lateral geniculate nucleus (LGN) become segregated into eye-specific patches (the ocular dominance columns) within their target, layer 4 of the primary visual cortex. This occurs as a consequence of activity-dependent synaptic competition between axons representing the two eyes. The possibility that this competition could be mediated through neurotrophin-receptor interactions was tested. Infusion of neurotrophin-4/5 (NT-4/5) or brain-derived neurotrophic factor (BDNF) into cat primary visual cortex inhibited column formation within the immediate vicinity of the infusion site but not elsewhere in the visual cortex. Infusion of nerve growth factor, neurotrophin 3 (NT-3), or vehicle solution did not affect column formation. These observations implicate TrkB, the common receptor for BDNF and NT-4/5, in the segregation of LGN axons into ocular dominance columns in layer 4. Moreover, they suggest that in addition to their better known roles in the prevention of cell death, neurotrophins may also mediate the activity-dependent control of axonal branching during development of the central nervous system.

[Results of the Strassmann operation at the Innsbruck University Gynecologic Clinic (1976-1991)]

Strassmann's operation in the presented manner has proven to be a valuable intervention in the case of infertility due to uterus bicornis or subseptus. The pregnancy rate observed after the operation was 92%, while the rate of abortion was 16%. Strassmann's operation requires smaller incisions compared with other metroplasties and was therefore continued. The establishment of the so-called 'abortus habitualis consulting hours' has led to a dramatic increase in the indication of a metroplasty. The proportion of patients with uterine malformations among those presenting with abortus habitualis amounts to 18%. Delivery by cesarean section 1-2 weeks before term should be taken into consideration from the obstetrical viewpoint. However, the decision for this treatment mode is also governed by the wish of the patient for minimal risk.

Regional distribution of brain-derived neurotrophic factor mRNA in the adult mouse brain

Brain-derived neurotrophic factor (BDNF) is a protein that allows the survival of specific neuronal populations. This study reports on the distribution of the BDNF mRNA in the adult mouse brain, where the BDNF gene is strongly expressed, using quantitative Northern blot analysis and in situ hybridization. All brain regions examined were found to contain substantial amounts of BDNF mRNA, the highest levels being found in the hippocampus followed by the cerebral cortex. In the hippocampus, which is also the site of highest nerve growth factor (NGF) gene expression in the central nervous system (CNS), there is approximately 50-fold more BDNF mRNA than NGF mRNA. In other brain regions, such as the granule cell layer of the cerebellum, the differences between the levels of BDNF and NGF mRNAs are even more pronounced. The BDNF mRNA was localized by in situ hybridization in hippocampal neurons (pyramidal and granule cells). These data suggest that BDNF may play an important role in the CNS for a wide variety of adult neurons.

Identification and characterization of a novel member of the nerve growth factor/brain-derived neurotrophic factor family

The survival and functional maintenance of vertebrate neurons critically depends on the availability of specific neurotrophic factors. So far, only two such factors, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) have been characterized and shown to have the typical features of secretory proteins. This characterization has been possible because of the extraordinarily large quantities of NGF in some adult tissues, and the virtually unlimited availability of brain tissue from which BDNF was isolated. Both NGF and BDNF promote the survival of distinct neuronal populations in vivo and are related in their primary structure, suggesting that they are members of a gene family. Although there is little doubt about the existence of other such proteins, their low abundance has rendered their identification and characterization difficult. Taking advantage of sequence identities between NGF and BDNF, we have now identified a third member of this family, which we name neurotrophin-3. Both the tissue distribution of the messenger RNA and the neuronal specificity of this secretory protein differ from those of NGF and BDNF. Alignment of the sequences of the three proteins reveals a remarkable number of amino acid identities, including all cysteine residues. This alignment also delineates four variable domains, each of 7-11 amino acids, indicating structural elements presumably involved in the neuronal specificity of these proteins.

Molecular cloning and expression of brain-derived neurotrophic factor

During the development of the vertebrate nervous system, many neurons depend for survival on interactions with their target cells. Specific proteins are thought to be released by the target cells and to play an essential role in these interactions. So far, only one such protein, nerve growth factor, has been fully characterized. This has been possible because of the extraordinarily (and unexplained) large quantities of this protein in some adult tissues that are of no relevance to the developing nervous system. Whereas the dependency of many neurons on their target cells for normal development, and the restricted neuronal specificity of nerve growth factor have long suggested the existence of other such proteins, their low abundance has rendered their characterization difficult. Here we report the full primary structure of brain-derived neurotrophic factor. This very rare protein is known to promote the survival of neuronal populations that are all located either in the central nervous system or directly connected with it. The messenger RNA for brain-derived neurotrophic factor was found predominantly in the central nervous system, and the sequence of the protein indicates that it is structurally related to nerve growth factor. These results establish that these two neurotrophic factors are related both functionally and structurally.

Clinical and hemodynamic results of extracardiac conduit reconstruction of the pulmonary artery

To evaluate the efficacy of pulmonary artery construction with a prosthetic conduit we have reviewed 25 operations in 22 of our patients. Early mortality was 12.0%, late mortality 5.3%. Up to 13 years postoperatively, 93.8% of the survivors are asymptomatic. Of 12 patients surviving more than 1 year, 11 have been catheterized after 1-11 years. Five had prior aortopulmonary shunts (mean duration 7.3 years); highest postrepair pulmonary artery pressure was 40 mmHg. Of seven recatheterized xenograft conduits, none had severe and four had mild obstruction. Reconstruction of pulmonary artery with xenograft conduit produced good clinical results. Long duration of aortopulmonary shunt prior to repair did not result in severe pulmonary artery hypertension. Obstruction of xenograft conduit has not been a major problem in our patients, but when necessary, reoperation for obstruction can be carried out safely as late as 11 years after the operation.