Best Abstracts from the ISCP 23rd Annual Scientific Meeting

ISCP Best Abstract Award 2018

Congratulations to the winners of the 2018 Young Investigator Awards for best abstracts:

Cavin-2 Deficiency Attenuates Cardiac Fibrosis and Dysfunction in Pressure-overloaded Hearts
Yusuke Higuchi, Takehiro Ogata, Masahiro Nishi, Satoaki Matoba

Comparative Analysis of the Effects EPA and DHA on Cultured Cardiomyocyte
Ayumi Katayama, Masafumi Funamoto, Kana Shimizu1, Mai Gempei, Yoichi Sunagawa, Hiromichi Wada, Koji Hasegawa, Tatsuya Morimoto

3D Ultrastructure of the “Arrhythmogenic” Purkinje Fibre-ventricular Junction in Rabbit Hearts
Shu Nakao, Il-Young Oh, Luke Stuart, Hiren Sitpura, Joseph Yanni, Sunil JSR Logantha, Xue Cai, Tobias Starborg, Halina Dobrzynski, Ashraf Kitmitto, Mark R Boyett

 

  

Prof Juan Carlos Kaski giving the award certificates to: Yusuki Higushi, Ayumi Katayama and Shu Nakao

 

Best Abstracts – Award Winners

Cavin-2 Deficiency Attenuates Cardiac Fibrosis and Dysfunction in Pressure-overloaded Hearts

Yusuke Higuchi1,Takehiro Ogata2,Masahiro Nishi1,Satoaki Matoba1
1Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, 2Department of Pathology and Cell Regulation, Kyoto Prefectural University of Medicine

Introduction:

Heart failure (HF) is a debilitating disease associated with high morbidity and mortality. The high mortality rate reflects inadequacy of modern therapy and calls for new mechanistic treatments. A major cause of HF is the adverse tissue remodeling with fibrosis. Excessive extracellular matrix (ECM) turnover is involved in poor outcome. Trans-differentiation of fibroblasts into activated myofibroblasts is a defining feature of fibrosis. Myofibroblasts express α -smooth muscle actin and secrete ECM proteins. Previous report showed that the cavin family gene is involved in cardiac function. However, the role of Cavin-2 in cardiac fibrosis and cardiac function remains unknown.

Methods and Results:

To examine the role of Cavin-2 in cardiac function, TAC was performed on WT mice and Cavin-2-/- mice. Four week after TAC procedure, left ventricular fractional shortening was significantly preserved in Cavin-2-/- mice. In addition, the fibrosis area was significantly attenuated in Cavin-2-/- mice. Moreover, mRNA expression of fibrosis genes was attenuated in the hearts of Cavin-2-/- mice 4 week after TAC. In vitro study, we isolated mouse embryonic fibroblasts (MEFs) from Cavin-2-/- mice and WT mice. Western blotting showed that α-smooth muscle actin protein level was decreased in TGF-β1 stimulated MEFs derived from Cavin-2-/- mice. Furthermore, mRNA expression of fibrosis genes was attenuated in MEFs derived from Cavin-2-/- mice.

Conclusions:

Our observations suggest that Cavin-2 contributes to the development of cardiac fibrosis and systolic dysfunction with the differentiation of fibroblasts into myofibroblasts. Cavin-2 may be a novel therapeutic target for cardiac fibrosis.


Comparative analysis of the effects of EPA and DHA on cultured cardiomyocyte

Ayumi Katayama1,Masafumi Funamoto1,2,Kana Shimizu1,2,Mai Gempei1,Yoichi Sunagawa1,2,3,Hiromichi Wada2,Koji Hasegawa1,2,3,Tatsuya Morimoto1,2,3
1Graduate School of Pharm Sci Univ of Shizuoka,2Kyoto Med,Ctr,3Shizuoka General Hospital

Introduction:

A major morphogenic change in heart failure is the hypertrophy of individual cardiomyocytes. Suppressing cardiomyocytes hypertrophy enables the the prevention and treatment of heart failure. Although many experimental studies and clinical intervention trials have shown the cardioprotective effect of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), little is known about the effects of these acids on cardiomyocyte hypertrophy. This study investigated whether DHA and EPA inhibit cardiac hypertrophy, and compared the effects of EPA and DHA on cultured cardiomyocytes.

Methods:

First, to compare the effects on hypertrophic responses, neonatal rat cultured cardiomyocytes were stimulated with 30µM phenylephrine (PE) in the presence or absence of EPA or DHA. Palmitic acid and stearic acid were used as controls. After 48 hours, cardiomyocyte surface area, hypertrophic response gene transcription, and the ratio of acetylated histone H3 were measured. Next, an in vitro HAT assay was performed to determine the direct effect of EPA and DHA on p300-HAT activity.

Results:

Treatment with either DHA or EPA significantly inhibited PE-induced hypertrophic response including myofibrillar organization, increase in cell size, and mRNA expression of ANF and BNP. Moreover, DHA and EPA repressed the PE-induced acetylation of histone-3 in cardiomyocytes to the same extent. The in vitro HAT assay revealed that EPA and DHA significantly inhibited p300-HAT activity.

Conclusions:

These findings suggest that EPA and DHA repress PE-induced hypertrophic responses in cardiomyocytes to the same extent, through the direct inhibition of histone acetyltransferase activity.


3D ultrastructure of the “arrhythmogenic” Purkinje fiber-ventricular junction in rabbit hearts

Shu Nakao1,3,Il-Young Oh1,4,Luke Stuart1,Hiren Sitpura1,Joseph Yanni1,Sunil JSR Logantha1,Xue Cai1,Tobias Starborg2,Halina Dobrzynski1,Ashraf Kitmitto1,Mark R Boyett1
1Div Cardiovasc Sci,Dept Biol Med Health,Univ Manchester,2Welcome Centre for Cell Matrix Res, Univ Manchester,3Dept Biomed Sci,Col Life Sci,Ritsumeikan Univ,4Dept Intern Med,Seoul Natl Univ Bundang Hospital

Introduction:

Ventricular arrhythmias are often associated with advanced heart failure and cardiomyopathies,and potentially originated from the Purkinje-ventricular (PV) junction where fast electric conduction is transferred to functional working myocardium. Despite its well-known electrophysiological property, in situ ultrastructure of the PV junction has yet been studied. Here we analyze three-dimensional nano-architecture of the PV junction in rabbit hearts sing Gatan 3View, a serial block face-scanning electron microscopy (SEM).

Methods and Results:

Small pieces of the PV junctions were dissected from rabbit hearts in oxygenized Tyrode solution, and processed with a modified method for standard SEM preparations. Up to 4000 consecutive images per resin block were acquired in 3View. IMOD software was used for segmentation and image processing. Free running Purkinje fibers were spindle-shaped, longitudinally arranged, and formed a bundle enveloped with connective tissue. Mitochondria and myofilaments were not packed but longitudinally aligned. The PV junction was made up of thin layers containing two different cell types. Type I junctional cells were characterized by thick and long column-shaped, whereas type II cells were wide and flat-shaped. PV cells in the both types were exhibited t-tubules, more organized mitochondria and myofilaments, and greater cell volume compared with Purkinje fibers. The junctional cells contacted some ventricular myocytes situated in the deeper layer.

Conclusion:

These findings correspond with unique functional features to trigger contraction of large mass of the ventricular myocytes.


Best Abstracts – Featured Abstracts

The following abstracts were also accepted for display at the meeting:

Relationship between VEGF-C levels and mortality in patients with peripheral artery disease

Nobutoyo Masunaga1,2, Shuichi Ura1, Mitsuru Ishi1,2, Takashi Unoki1, Daisuke Takagi2, Moritake Iguchi1,2, Kensuke Takabayash2, Yugo Yamashita2, Yasuhiro Hamatani2, Hisashi Ogawa1,2, Noriko Satoh-Asahara3, Akira Shimatsu3, Mitsuru Abe1,2, Masaharu Akao1,2, Koji Hasegawa1, Hiromichi Wada1
1Division of Translational Research,Department of Cardiology,Department of Endocrinoloy, Metabolism, and Hypertension,Division of Diabetes Research, National Hospital Organization Kyoto Medical Center,  Kyoto, Japan

The lymphatic system has been suggested to play an important role in cholesterol metabolism and cardiovascular disease. Vascular endothelial growth factor-C (VEGF-C) plays a key role in lymphangiogenesis. Recently, we demonstrated that VEGF-C is closely associated with dyslipidemia and atherosclerosis. However, the relationship between VEGF-C levels and mortality in patients with atherosclerotic disease is unknown. We performed a prospective cohort study involving a total of 204 patients with peripheral artery disease. Patients were followed up over 4 years. The outcome was all-cause death. Serum levels of VEGF-C were measured at the baseline. Patients were divided into two groups based on the median of VEGF-C levels. During the follow-up, a total of 53 patients (26.0%) died from any cause. In Kaplan-Meier analysis, the low-VEGF-C group had a significantly higher risk of all-cause death compared with the high-VEGF-C group (P<0.001 by log-rank test). Furthermore, multivariate Cox proportional hazard analysis revealed that the VEGF-C level was significantly and inversely associated with the risk of all-cause death after adjustment for age, sex, traditional risk factors, chronic kidney disease, and the Fontaine stages (adjusted hazard ratio, 0.70 for 1-SD increase; 95% confidence interval, 0.52-0.95; P=0.02). In conclusion, a low VEGF-C value was independently associated with the risk of all-cause mortality in patients with peripheral artery disease.


VEGF-C and cardiovascular mortality in patients undergoing drug-eluting stent implantation

Takashi Unoki1, Shuichi Ura1, Daisuke Takagi2, Nobutoyo Masunaga2, Mitsuru Ishii2, Moritake Iguchi2, Kensuke Takabayashi2, Yugo Yamashita2, Yasuhiro Hamatani2, Hisashi Ogawa1,2, Noriko Satoh-Asahara3,  Akira Shimatsu3, Mitsuru Abe2, Masaharu Akao1,2, Koji Hasegawa1, Hiromichi Wada1
1Division of Translational Research,Department of Cardiology,Department of Endocrinology, Metabolism,  and Hypertension,Division of Diabetes Research, National Hospital Organization Kyoto Medical Center,  Kyoto, Japan

The lymphatic system has been suggested to play an important role in cholesterol metabolism and cardiovascular disease. Vascular endothelial growth factor-C (VEGF-C) plays a key role in lymphangiogenesis. Recently, we demonstrated that VEGF-C is closely associated with dyslipidemia and atherosclerosis. However, the relationship between VEGF-C levels and cardiovascular mortality in patients with established coronary artery disease is unknown. We performed a prospective cohort study involving a total of 433 patients who underwent successful drug-eluting stent implantation. The prescription rate of statin was 100% at the baseline. Patients were followed up over 4 years. The outcome was cardiovascular death. Pre-procedural serum levels of VEGF-C were measured. Patients were divided into two groups based on the median of VEGF-C levels. During the follow-up, a total of 23 patients (5.3%) died from cardiovascular disease. In Kaplan-Meier analysis, the low-VEGF-C group had a significantly higher risk of cardiovascular death compared with the high-VEGF-C group (P<0.001 by log-rank test). Furthermore, multivariate Cox proportional hazard analysis revealed that VEGF-C levels were significantly and inversely associated with the risk of cardiovascular death after adjustment for traditional risk factors and chronic kidney disease (adjusted hazard ratio, 0.55 for 1-SD increase; 95% confidence interval, 0.34-0.87; P=0.011). In conclusion, a low VEGF-C value was independently associated with cardiovascular mortality in patients after drug-eluting stent implantation.


The GATA4 acetylation site plays a key role in the development of cardiomyocyte hypertrophy

Satoshi Shimizu1, Yoichi Sunagawa1,2,3, Kodai Hara1, Asami Hishiki1, Masafumi Funamoto1,2, Sari Nurmila1, Kana Shimizu1, Yusuke Miyazaki1,2,3, Yasufumi Katanasaka1,2,3, Hiromichi Wada2, Koji Hasegawa1,2, Hiroshi Hashimoto1, Tatsuya Morimoto1,2,3
1Grad. Sch. of Pharm. Sci.,Univ. Shizuoka,2Clin. Res. Inst.,Kyoto Med. Ctr.,3Shizuoka Gen. Hosp.

Introduction:

The zinc finger protein GATA4 is a transcription factor that associates with the intrinsic histone acetyltransferase p300 and regulates myocardial transcriptional activity in response to hypertrophic stimuli. It is known that GATA1, another member of the GATA transcription family, forms a homo-dimer and regulates transcriptional activity. However, whether GATA4 forms a homo-dimer, and what its relationship is to hypertrophic responses, are still unknown.

Methods and Results:

GST pull-down assay demonstrated that GATA4 dimerization required the GATA4 acetylation site from residues 308-326. Overexpression of a mutant containing a 3xGATA4 acetylation site (3xG4D) both prevented p300-induced GATA4 dimerization and inhibited p300/GATA4-induced ANF and ET-1 promoter activity without inhibiting GATA4 acetylation. In cardiomyocytes, the overexpression of 3xG4D inhibited phenylephrine-induced cardiomyocyte hypertrophy. To perform a crystal structure analysis, a recombinant GATA4 fragment, including an acetylation site with a GST tag, was purified with GS4B beads. The GST tag was cleaved using HRV3C protease and applied to an anion-exchange column followed by a size-exclusion column. Crystallization was performed using a commercial kit to screen crystallization conditions and then optimize them. X-ray diffraction data was collected with the BL-17A beamline at Photon Factory.

Conclusions:

These results suggest that the dimerization of GATA4 is involved in hypertrophic responses in cardiomyocytes. This finding may contribute to the development of new heart failure drugs.


TBL1 suppresses cardiomyocyte hypertrophy by regulating the interaction between HDAC3 and GATA4

 Yasufumi Katanasaka1,2,3, Masatoshi Namiki1, Yoichi Sunagawa1,2,3, Yusuke Miyazaki1,2,3, Hiromichi Wada2, Koji Hasegawa2, Tatsuya Morimoto1,2,3
1Division of Molecular Medicine, Graduate School of Pharmaceutical Science, University of Shizuoka,Division of Translational Research, Clinical Research Institute, Kyoto Medical Center, National Hospital Organization, Shizuoka General Hospital

Cardiac hypertrophy is a risk factor for the development of heart failure. To elucidate underlying molecular mechanism is necessary for the development of novel pharmacological therapy targeting to pathological cardiac hypertrophy. We have previously reported that the acetylation of GATA4 by p300 is essential for cardiomyocyte hypertrophy and heart failure. In the present study, we have identified transducin beta like protein 1 (TBL1) as a novel GATA4-binding protein by tandem affinity purification and mass spectrometry analyses. Overexpression of TBL1 significantly repressed p300/GATA4-induced activations of atrial natriuretic peptide (ANP) and endothelin-1 (ET-1) promoters in HEK293T cells. Furthermore, overexpression of TBL1 significantly inhibited phenylephrine (PE)- induced hypertrophic responses including an increase in the cell size and the transcriptional activation of ANP and ET-1 promoters in primary cultured cardiomyocyte. Conversely, knockdown of TBL1 by RNAi increased PE-induced mRNA expression of ANP and BNP. TBL1 repressed p300-induced acetylation of GATA4 and enhanced the binding between HDAC3 and GATA4. The treatment with RGFP966, a specific inhibitor of HDAC3, rescued the TBL1- mediated inhibition of hypertrophic responses in cultured cardiomyocytes. Finally, the interaction of TBL1 with HDAC3 decreased by treatment with PE in cardiomyocytes. These findings have demonstrated that TBL1 suppresses p300/GATA4-dependent gene transcription and cardiomyocyte hypertrophy by regulating the interaction between HDAC3 and GATA4.


The role of p53 localized in cytosol and mitochondria during reprogramming to iPS cells

Tomomi Akama1, Araya Tenghattakorn1, Motoharu Yamasaki1, Yukihiro Harada1, Dai Ihara1,  Tomoe Ueyama1, Takahiro Sogo 2, Shu Nakao 1, Teruhisa Kawamura1
1Dept. of Biomed. Sci., Col. of Life Sci., Ritsumeikan Univ.,Global Innov. Res. Org. Ritsumeikan Univ.

Previous studies including ours suggest that tumor repressor p53 is activated during somatic cell reprogramming, and efficiency of induced pluripotent stem cell (iPSC) formation is limited through transactivation of p53 target genes leading to apoptosis and cell cycle arrest. Recent studies revealed non-transcriptional effects of p53 on mitochondria that directly trigger apoptosis. Thus, we attempted to examine the role of cytosolic and mitochondrial p53 in iPSCs.

We constructed plasmids to express EGFP fused with either p53 wild-type (WT) and its mutant K27R which is expected abundantly to localize to mitochondria. Then, we performed live cell imaging using mouse embryonic fibroblasts (MEFs) infected with retroviruses encoding p53 WT-EGFP or p53 K27R-EGFP. While EGFP-fused with K27R as well as WT was observed in both cytosol and nucleus at the basal condition, nuclear expression was significantly enhanced after irradiation, suggesting nuclear translocation of p53 by DNA damage. Localization of p53 K27R seemed similar to that of p53 WT under fluorescence microscopy. Inhibitory effects of p53 on cell proliferation were, however, not observed in K27R-expressing cells. Since the results suggest the role of K27R except nucleus, we further tested whether K27R affects the efficiency of iPSC colony formation. We introduced combinations of the reprogramming factors, Oct4, Sox2, and Klf4 with or without c-Myc into MEFs together with either p53 WT or p53 K27R. Interestingly, K27R mutant repressed iPSC formation to similar extent as p53 WT. These results above suggest that cytosolic p53 would a potential negative regulator for somatic cell reprogramming in a transcription-independent manner.


The mechanism of Hey2 expression in cardiac development

Dai Ihara1,2, Yusuke Watanabe2, Daily Seya2, Yukihiro Harada1,2, Osamu Nakagawa2, Teruhisa Kawamura1
1Ritsumeikan University Department of Life Science,2  National Cerebral and Cardiovascular Center Department of Molecular Physiology

Hairy/enhancer-of-split related with YRPW motif proteins, known as Hey family, were reported to encode a downstream transcription factor of Notch and ALK1 signaling pathways. Among the three Hey family members (Hey1, Hey2, HeyL), Hey2 null mice show postnatal lethality with various cardiac malformations, ventricular septum defect, right ventricular hypoplasia, and tricuspid atresia. Hence, it is clear that Hey2 is cruicial during heart formation. Hey1 and Hey2 are expressed in the atrium and ventricle, respectively, throughout the cardiac development. Thus, we focused on the ventricular specific expression of Hey2 to reveal the molecular transcription mechanism.

Enhancer activity was investigated by multistep analysis. First, Hey2 enhancer regions were predicted by in silico ChIP-seq analysis including cardiac transcription factor bindings and histone modification. Second, the response of the enhancers were examined by Lusicerase assay against cardiac transcription factors; involvement Gata4, Nkx2.5 and Tbx5. Finally, enhancer activity was confirmed with transgenic (Tg) mice LacZ reporter system using the minimal promoter. The analysis of Tg mouse embryo heart showed that two enhancers had region specific activity respectively.

In this study, we found Hey2 ventricular specific expression was not only regulated by one enhancer, but by multiple enhancers specific to each region. This novel finding on Hey2 expression regulation is significant to understand cardiac development.


Relationship between VEGF-C levels and all-cause mortality in patients with chronic heart failure

 Moritake Iguchi1,2, Shuichi Ura1, Nobutoyo Masunaga1,2, Mitsuru Ishii1,2, Takashi Unoki1,2, Hisashi Ogawa1,2, Daisuke Takagi2, Noriko Satoh-Asahara3, Akira Shimatsu4, Mitsuru Abe1,2, Masaharu Akao1,2, Koji Hasegawa1, Hiromichi Wada1
1Division of Translational Research,Department of Cardiology,Department of Endocrinology, Metabolism, and Hypertension,Division of Diabetes Research, National Hospital Organization Kyoto Medical Center, Kyoto, Japan

The lymphatic system has been suggested to play an important role in cardiovascular disease. Vascular endothelial growth factor-C (VEGF-C) plays a key role in lymphangiogenesis. However, the relationship between VEGF-C levels and mortality in patients with chronic heart failure is unknown. We performed a prospective cohort study involving a total of 220 symptomatic patients with chronic heart failure. Patients were followed up over 4 years. The outcome was all-cause death. Serum levels of VEGF-C were measured at the baseline. Patients were divided into two groups based on the median of VEGF-C levels. During the follow-up, a total of 59 patients (26.8%) died from any cause. In Kaplan-Meier analysis, the low-VEGF-C group had a significantly higher risk of all-cause death compared with the high-VEGF-C group (P=0.003 by log-rank test). Furthermore, multivariate Cox proportional hazard analysis revealed that the VEGF-C level was significantly and inversely associated with the risk of all-cause death after adjustment for established risk factors (i.e. age, sex, the body mass index, hypertension, diabetes, previous heart failure hospitalization, coronary artery disease, persistent/permanent atrial fibrillation, chronic kidney disease, anemia, and a reduced left ventricular ejection fraction [<50%]) (adjusted hazard ratio, 0.72 for 1-SD increase; 95% confidence interval, 0.52-0.99; P=0.04). In conclusion, a low VEGF-C value was independently associated with the risk of all-cause mortality in patients with chronic heart failure.


A PRMT5 Selective Inhibitor EPZ015666 Suppressed TAC-induced Left Ventricular Dysfunction

Kazuma Hanajima1, Yusuke Miyazaki1,2,3, Yasufumi Katanasaka1,2,3, Hiroki Honda1, Hunamoto Masafumi1,2,  Nurmila Sari1, Sunagawa Yoichi1,2,3, Koji Hasegawa1,2, Tatsuya Morimoto1,2,3
1Division of Molecular Medicine, School of Pharmaceutical Sciences, University of Shizuoka, Japan, Division of Translational Research, Kyoto Medical Center, Japan,3 Shizuoka General Hospital, Japan

Background:

The mortality of heart disease has been increasing in all over the world. Cardiac hypertrophy is an important risk factor for heart failure. We have previously reported that Protein arginine methyltransferase 5 (PRMT5) specific inhibitor EPZ015666 (EPZ) suppressed cardiomyocyte hypertrophy in neonatal rat cardiomyocytes. However, it is unclear whether EPZ can suppress transverse aortic constriction (TAC)-induced cardiac hypertrophy and systolic dysfunction in vivo.

Methods and Results:

TAC or sham operation was performed on Male C57BL/6J mice at 8-10 weeks-old. EPZ or vehicle was administrated to mice every morning for 8 weeks beginning on the next day of operation. Echocardiography was performed at 8 weeks after surgery. Fractional shortening (FS) and ejection fraction (EF) was significantly decreased in TAC+vehicle group and EPZ significantly improved them. Following the echocardiography, mice were killed and body weight (BW), tibia length (TL), and heart weight (HW) were measured. HE staining and qRT-PCR were performed. There were no significant difference in BW between TAC+EPZ group and TAC+vehicle group. HW/TL ratio, cardiomyocyte diameter, and hypertrophic gene expression were significantly suppressed in TAC+EPZ group compared with TAC+vehicle group.

Conclusion:

These results indicated that EPZ suppressed TAC-induced cardiac hypertrophy and systolic dysfunction. EPZ may be a new therapeutic agent for heart failure.


Cell-specific Mathematical Modeling of hiPSC-CMs and Its Potential for Prediction of Drug Testing

Hirohiko Kohjitani1, Shigeya Koda2, Yukiko Himeno2, Takeru Makiyama1, Yimin Wuriyanghai1, Yuta Yamamoto1, Takeshi Kimura1, Akinori Noma2, Akira Amano1
1Cardiovascular Medicine, Kyoto University Hospital,College of Life Sciences, Ritsumeikan University

Background:

Human induced pluripotent stem cells (hiPSCs) derived cardiomyocytes (-CMs) are expected tool for preclinical evaluation of the safety and efficacy of compounds on the heart. Its action potential (AP) parameters were measured in order to estimate pro-arrhythmic effects of new drugs, mutation of ion-channels, and so on. But, hiPSC-CMs exhibit varying AP morphologies, and even exhibit paradoxical reaction for some compounds.

Hypothesis:

Variations of APs of hiPSC-CMs express their total balance of ion-currents, and might affect the result of drug-testing. So, in order to interpret the results of drug-testing using hiPSC-CMs platform accurately, cell-specific precise mathematical modeling of hiPSC-CMs may be useful.

Methods:

We developed novel hiPSC-CMs mathematical models based on HuVEC model (Asakura et al, 2014), adopting experimental data of ionic channels. We recorded APs from 40 hiPSC-CMs, and reproduced all AP morphologies simulationally by changing conductance of each ion current. After that, in-silico IKr-blocking test was performed.

Results:

All 40 AP morphologies were successfully recapitulated within 5% error range. In simulational IKr-blocking test, AP duration (APD) prolongation was observed in 15 cells (37.5%). In 21 cells, APD prolongation and rising of maximum diastolic potential (MDP) was observed. In 4 cells, APD shortening and rising of MDP was observed. All APD shortening cell has morphological character of MDP > -68.0mV.

Conclusion:

Our new mathematical models can reproduce experimental AP morphology precisely. To interpret the results of hiPSC-CMs drug testing appropriately, cell-specific computer simulation is very useful.


Characteristics of lipid profile of LPL deficiency in Japan – Comparison with non-LPL deficiency

Kobayashi Junji
Department of General Medicine Kanazawa Medical University

Objective:

Lipoprotein lipase deficiency is a rare autosomal recessive lipid disorder caused by a mutation in the gene which codes lipoprotein lipase and is characterized by severe hypertriglyceridemia. On the other hand, we encounter subjects with very severe hypertriglyceridemia but have no LPL deficient (non-LPLdeficiency). In this study, we clarify the differences in lipid profiles between LPL deficiency and non-LPL deficiency.

Methods:

We analyzed 16 patients in 13 articles on LPL deficiency published by Japanese researchers since 1990 and 11 non-LPL deficiency as controls. The differences in lipid values between the two groups were analyzed using Mann-Whitney U test.

Results:

In LPL deficiency (n=16, F/M 5/11) vs. non-LPL deficiency(n=11, F/M 5/6), TC (mg / dL) were 267 ± 214 and 328 ± 52 (p=0002), respectively; TG (mg / dL) were 2446 ± 2234 and 1477 ± 670 (p=0.29), respectively and HDL-C( mg / dL) were 14.2 ± 5.1 and 31.8 ± 6.01 (p<0.0001), respectively. To assess the usefulness of TG and HDL-C values to discriminate LPL deficiency from non-LPL deficiency, we conducted ROC analysis. In the case of TG, the area under the ROC curve (AUC) was 0.693 whereas in the case of HDL-C, the AUC was 0.991. These results indicate that HDL-C may be an excellent value for discriminating LPL deficiency from non-LPL deficiency. When we used HDL-C of 26.5 mg/dL as cut value, the detection sensitivity and specificity of the non-LPL deficient case were 0.82 and 1.00, respectively.

Conclusion:

It was suggested that the HDL-C value may be extremely useful for discriminating the presence or absence of LPL deficiency in severe hypertriglyceridemia.


Omega-6 polyunsaturated fatty acid levels and delirium in patients with acute cardiovascular disease

Yurina Sugita, Tetsuro Miyazaki, Kazunori Shimada, Megumi Shimizu, Mitsuhiro Kunimoto, Tatsuro Aikawa, Shohei Ouchi, Tomoyasu Kadoguchi, Yuko Kawaguchi, Tomoyuki Shiozawa, Masaru Hiki, Syuhei Takahashi, Miho Yokoyama, Hiroshi Iwata, Hiroyuki Daida
Department of Cardiology, Juntendo Graduate School of Medicine

Background:

Delirium frequently occurs in patients admitted to the intensive care unit and is associated with mortality and morbidity. Although several studies reported associations between polyunsaturated fatty acids (PUFAs) and cognitive disorders, the association between PUFAs and delirium in patients with acute cardiovascular disease remains unknown.

Methods and Results:

We enrolled 589 consecutive patients (mean age: 70 ± 14 years) admitted to the coronary care unit of Juntendo University Hospital from January 2015 to December 2016. Fasting serum PUFA levels were measured within 24 h of admission. Delirium was defined as patients with a delirium score ≥4 using the Intensive Care Delirium Screening Checklist. Delirium was present in 54 patients. The levels of dihomo-gamma-linolenic acid (DGLA) was significantly lower in patients with delirium than in those without delirium (DGLA: 23.1 ± 10.3 vs. 31.4 ± 12.6 μg/ml, P < 0.0001), whereas AA and omega-3 PUFAs did not differ between the 2 groups. In addition, DGLA and AA, but not omega-3 PUFA, were negatively associated with the delirium score (DGLA: P < 0.0001; AA: P = 0.002).

Conclusion:

Low omega-6 PUFA levels on admission were significantly associated with delirium in the coronary care unit, indicating that low omega-6 PUFA levels may identify patients at high risk of developing delirium.