Trimetazidine improves left ventricular global longitudinal strain value in patients with heart failure with reduced ejection fraction due to ischemic heart disease

Heart failure with reduced ejection fraction (HFrEF) due to ischemic heart disease (IHD) showed a progressive decline in left ventricular contractile function. However, no previous study has examined the left ventricular global longitudinal strain (LV GLS) parameter that represents LV contractile function. We investigated whether trimetazidine could improve the LV GLS value in patients with HFrEF due to IHD. We performed a double-blind, randomized controlled trial (RCT) including 26 patients with HFrEF due to stable IHD who were given modified-release trimetazidine 35 mg twice per day (n = 13) or placebo (n = 13) for 3 months in addition to standard medication. Left ventricular systolic function including GLS values was assessed at baseline and after 3 months using echocardiography. A total of 25 participants (13 control and 12 trimetazidine groups) were recruited with a baseline average age of 57.1 ± 10 years, and LV ejection fraction (LVEF) value of 34.6% ± 4.4%, and a GLS value of 7.4% ± 2.1%. Baseline clinical characteristics and echocardiogram were similar between the two groups. There was significant GLS improvement in the trimetazidine group (-6.9% ± 2.4% to -8.4% ± 2.6%, p = 0.000), but no significant differences were noted in the control group. The GLS improvement was significantly higher in the trimetazidine group than the control (1.5% + 0.9% vs. -0.7% + 1.7%, p = 0.001). No adverse drug reactions from the administration of trimetazidine in this study. Trimetazidine may improve GLS values in patients with HFrEF due to IHD.

The initial validation of indonesian version of heartqoL: a short health-related quality of life questionnaire for post-myocardial infarction patients

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Indonesia Ministry of Health

Background

HeartQoL questionnaire was developed to measure specific health-related quality of life for post-myocardial infarction patients. However, it has not been adapted and tested for its validity and reliability for Indonesian population.

Purpose

To assess the validity and reliability of the Indonesian version of the HeartQoL Questionnaire in post-acute myocardial infarction patients.

Method

We admitted 102 Indonesian-native speaking patients treated at a tertiary hospital who experienced the first episode of acute myocardial infarction (93% male; mean age = 56.8 years) into the study. They were randomly contacted to fill out the Indonesian version of HeartQoL and SF-36 questionnaire independently. Construct validity of the HeartQoL questionnaire was analyzed using exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and convergent validity was assessed by correlation of the HeartQoL and SF-36 similar subscales, whereas internal consistency was examined using Cronbach's Alpha value.

Results

EFA showed that the Indonesian version of HeartQoL consisted of 14-items with a 2-factor structure, and CFA supported the results by showing a satisfactory fit, CFI = 0.972, TLI = 0.961, and RMSEA = 0.075. Convergent validity was shown by r > 0.50 for physical and mental domain. The internal consistency of the HeartQoL scales was indicated by the Cronbach's Alpha value of 0,865-0.953.

Conclusions

The Indonesian version of the HeartQol questionnaire is a valid and reliable measure to assess the quality of life of patients after myocardial infarction.

Recurrent SARS-CoV-2 RNA positivity after COVID-19: a systematic review and meta-analysis

Present study aimed to estimate the incidence of recurrent SARS-CoV-2 RNA positivity after recovery from COVID-19 and to determine the factors associated with recurrent positivity. We searched the PubMed, MedRxiv, BioRxiv, the Cochrane Library, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry for studies published to June 12, 2020. Studies were reviewed to determine the risk of bias. A random-effects model was used to pool results. Heterogeneity was assessed using I². Fourteen studies of 2568 individuals were included. The incidence of recurrent SARS-CoV-2 positivity was 14.8% (95% confidence interval [CI] 11.44–18.19%). The pooled estimate of the interval from disease onset to recurrence was 35.4 days (95% CI 32.65–38.24 days), and from the last negative to the recurrent positive result was 9.8 days (95% CI 7.31–12.22 days). Patients with younger age and a longer initial illness were more likely to experience recurrent SARS-CoV-2 positivity, while patients with diabetes, severe disease, and a low lymphocyte count were less likely to experience. Present study concluded that the incidence of recurrent SARS-CoV-2 positivity was 14.8% suggesting further studies must be conducted to elucidate the possibility of infectious individuals with prolonged or recurrent RNA positivity.

The Protective Effect of Azelnidipine for the Prevention of Heart Fibrosis Occurrence on Balb/c Mice with Iron Overload

Background: Iron overload can cause DNA oxidation which increase TGF β1, type 1 fibrilarprotein and myocardium fibrosis. Myocardium fibrosis is the main cause of death on the state of iron overload. The iron influx towards the cell during iron overload is still unknown, some research suggested LTCC acts as iron influx. This research aims to investigate the role of azelnidipine as type L calcium channel blocker, lowering TGF β1, collagen and myocardium fibrosis. Method: The research subjects consisted of 25 male Balb-C mice(8 weeks, 30-40mg) divided into 5 groups. Group 1 (NaCl+S) 0,3 cc Na Cl 0,9% (I.P) and drug solvent (Aquabidest, CMC and Nipagin) orally. Group 2Fe+S) 0.3 cc 1,5 mg Fe+sucrose (Venofer®) (I.P) and drug solvent (Aquabidest, CMC and Nipagin) orally. Group 3 (Fe+Dfx) 1,5 mg Fe+sucrose (Venofer®) (I.P) and deferasirox 20 mg/kg body weight/day orally, group 4 (Fe+Azl) 1,5 mg Fe+sucrose (Venofer®) (I.P) and azelnidipine 14 mg/day orally and group 5 (Fe+Dfx-Azl) 1,5 mg Fe+sucrose (Venofer®) (I.P) and mixture of deferasirox 20 mg/kg body weight/day and azelnidipine 14 mg/day orally. Fe-sucorse was diluted with NaCl 0.9 %. Intraperitoneal injection were administered intermittently for 60 days of treatment. Result: The highest Expression of TGF β, collagen I and fibrosis area fractions are in group Fe+S. The result of Post Hoc test between 2 treatment groups indicated that there were no difference in TGF β expression between groups NaCl+S with Fe+Dfx (P>0.05) , Fe+Dzl (P>0.05). There are no significant in collagen expression between groups NaCl+S with Fe+Dfx (P > 0.05) ,Fe+Dzl (P>0.05). Conclusion: Azelnidipine, LTCC have roles on the influx of iron into the myocardium, lowering TGF β, collagen Iexpressionsand myocardium fibrosis. Bangladesh Journal of Medical Science Vol.19(2) 2020 p.223-228

Optimization of PCR Condition: The First Study of High Resolution Melting Technique for Screening of APOA1 Variance

BACKGROUND

High resolution melting (HRM) is a post-PCR technique for variant screening and genotyping based on the different melting points of DNA fragments. The advantages of this technique are that it is fast, simple, and efficient and has a high output, particularly for screening of a large number of samples. APOA1 encodes apolipoprotein A1 (apoA1) which is a major component of high density lipoprotein cholesterol (HDL-C). This study aimed to obtain an optimal quantitative polymerase chain reaction (qPCR)-HRM condition for screening of APOA1 variance.

METHODS

Genomic DNA was isolated from a peripheral blood sample using the salting out method. APOA1 was amplified using the RotorGeneQ 5Plex HRM. The PCR product was visualized with the HRM amplification curve and confirmed using gel electrophoresis. The melting profile was confirmed by looking at the melting curve.

RESULTS

Five sets of primers covering the translated region of APOA1 exons were designed with expected PCR product size of 100-400 bps. The amplified segments of DNA were amplicons 2, 3, 4A, 4B, and 4C. Amplicons 2, 3 and 4B were optimized at an annealing temperature of 60 °C at 40 PCR cycles. Amplicon 4A was optimized at an annealing temperature of 62 °C at 45 PCR cycles. Amplicon 4C was optimized at an annealing temperature of 63 °C at 50 PCR cycles.

CONCLUSION

In addition to the suitable procedures of DNA isolation and quantification, primer design and an estimated PCR product size, the data of this study showed that appropriate annealing temperature and PCR cycles were important factors in optimization of HRM technique for variant screening in APOA1.

Carvedilol Suppresses Apoptosis and Ion Channel Remodelling of HL-1 Cardiac Myocytes Expressing E334K cMyBPC

BACKGROUND

Besides its antiarrhythmic action, carvedilol has an activity to suppress cardiac tissue damage. However, it is unknown whether it has any effect on cellular apoptosis and ion channel remodelling.

PURPOSE

To know whether carvedilol has any effect on apoptosis and ion channel remodeling of HL-1 cells expressing E334K MyBPC, and comparing it with bisoprolol.

METHOD

We examined effects of carvedilol and bisoprolol on the levels of pro- and anti-apoptotic proteins and ion channels as well as apoptosis of HL-1 cells transfected with E334K MyBPC using Western blot and flow cytometry.

RESULTS

Carvedilol decreased the protein levels of p53, Bax and cytochrome c and increased that of Bcl-2 in HL-1 cells expressing E334K MyBPC. Bisoprolol failed to affect the protein levels. Both carvedilol and bisoprolol increased the protein levels of Cav1.2 but not that of Nav1.5. Carvedilol was stronger than bisoprolol at decreasing the number of annexin-V positive cells in HL-1 cells expressing E334K MyBPC.

CONCLUSION

Carvedilol suppressed apoptosis of HL-1 cells expressing E334K MyBPC through modification of pro- and anti-apoptotic proteins, whose was associated with an increase of Cav 1.2 protein expression.

Weak interaction of an inhibitor in the 20S proteasome

Proteasomes are the multicatalytic protein complexes with huge molecular weight. It is well known that the ubiquitin proteasome system plays an important role in regulated proteolysis. The 26S proteasome is composed of two 19S regulating components and a 20S proteasome. The 20S proteasome forms barrel shape and is composed of four rings, α- and β-rings; each ring contains highly homological seven α-subunits (1~7) and seven β-subunits (1~7), N-terminal tails of α-ring subunit form a gate to facilitate substrate entry. Each of 1, 2 and 5 β–subunit has different enzyme activity; 1 is caspase-, 2 tryptic- and 5 chymotryptic- like activity, respectively. We found a new protease inhibitor compound-A, which interacts weakly against proteasome. In order to elucidate the binding mode of the compound-A to proteasome, structure determination of the 20S proteosme complexed with compound-A was carried out. Isolated and concentrated 20S proteasome was co-crystallized with compound-A. Sitting drop vapor diffusion method was applied using 0.1M MES-NaOH (pH 6.5), 35% MPD, 50 mM magnesium acetate as a reservoir solution and 10 mg/ml proteasome and 20 mM compound-A as a sample solution. Crystals are isomorphous with the previous report [1]. Diffraction images were recorded at 100 K by using ADSC Quantum 210r CCD detector at NW12A of Photon Factory, Tsukuba, Japan. Initial phases were determined by molecular replacement method using the structure of the yeast 20S proteasome [1RYP] as a starting model and the structure model with a ligand was refined by using Refmac5 in CCP4 program package with an R value of 16.5% at 2.85 Å. The electron densities have been observed at the active site as mentioned above in the β-ring. Binding site of compound-A is closed to Tyr170 and Thr1 of the β5 subunit. The compound-A binds weakly to their residues by hydrogen bondings. It is quite different from the binding mode of the known potent proteasome inhibitor bortezomib [2].

Electrophysiological properties of prion-positive cardiac progenitors derived from murine embryonic stem cells

BACKGROUND

The prion protein (PrP) has been reported to serve as a surface maker for isolation of cardiomyogenic progenitors from murine embryonic stem (ES) cells. Although PrP-positive cells exhibited automaticity, their electrophysiological characteristics remain unresolved. The aim of the present study was therefore to investigate the electrophysiological properties of PrP-positive cells in comparison with those of HCN4p-or Nkx2.5-positive cells.

METHODS AND RESULTS

Differentiation of AB1, HCN5p-EGFP and hcgp7 ES cells into cardiac progenitors was induced by embryoid body (EB) formation. EBs were dissociated and cells expressing PrP, HCN4-EGFP and/or Nkx2.5-GFP were collected via flow cytometry. Sorted cells were subjected to reverse transcriptase-polymerase chain reaction, immunostaining and patch-clamp experiments. PrP-positive cells expressed mRNA of undifferentiation markers, first and second heart field markers, and cardiac-specific genes and ion channels, indicating their commitment to cardiomyogenic progenitors. PrP-positive cells with automaticity showed positive and negative chronotropic responses to isoproterenol and carbamylcholine, respectively. Hyperpolarization-activated cation current (I(f)) was barely detectable, whereas Na(+) and L-type Ca(2+) channel currents were frequently observed. Their spontaneous activity was slowed by inhibition of sarcoplasmic reticulum Ca(2+) uptake and release but not by blocking I(f). The maximum diastolic potential of their spontaneous firings was more depolarized than that of Nkx2.5-GFP-positive cells.

CONCLUSIONS

PrP-positive cells contained cardiac progenitors that separated from the lineage of sinoatrial node cells. PrP can be used as a marker to enrich nascent cardiac progenitors.

Transcriptional activation of the anchoring protein SAP97 by heat shock factor (HSF)-1 stabilizes K(v) 1.5 channels in HL-1 cells

BACKGROUND AND PURPOSE

The expression of voltage-dependent K⁺ channels (K_v) 1.5 is regulated by members of the heat shock protein (Hsp) family. We examined whether the heat shock transcription factor 1 (HSF-1) and its inducer geranylgeranylacetone (GGA) could affect the expression of K_v1.5 channels and its anchoring protein, synapse associated protein 97 (SAP97).

EXPERIMENTAL APPROACH

Transfected mouse atrial cardiomyocytes (HL-1 cells) and COS7 cells were subjected to luciferase reporter gene assay and whole-cell patch clamp. Protein and mRNA extracts were subjected to Western blot and quantitative real-time polymerase chain reaction.

KEY RESULTS

Heat shock of HL-1 cells induced expression of Hsp70, HSF-1, SAP97 and K_v1.5 proteins. These effects were reproduced by wild-type HSF-1. Both heat shock and expression of HSF-1, but not the R71G mutant, increased the SAP97 mRNA level. Small interfering RNA (siRNA) against SAP97 abolished HSF-1-induced increase of K_v1.5 and SAP97 proteins. A luciferase reporter gene assay revealed that the SAP97 promoter region (from −919 to −740) that contains heat shock elements (HSEs) was required for this induction. Suppression of SIRT1 function either by nicotinamide or siRNA decreased the level of SAP97 mRNA. SIRT1 activation by resveratrol had opposing effects. A treatment of the cells with GGA increased the level of SAP97 mRNA, K_v1.5 proteins and I_Kur current, which could be modified with either resveratrol or nicotinamide.

CONCLUSIONS AND IMPLICATIONS

HSF-1 induced transcription of SAP97 through SIRT1-dependent interaction with HSEs; the increase in SAP97 resulted in stabilization of K_v1.5 channels. These effects were mimicked by GGA.

Effect of losartan and benzbromarone on the level of human urate transporter 1 mRNA

Both an angiotensin II receptor blocker, losartan (CAS 124750-99-8) and a serum urate lowering agent, benzbromarone (CAS 3562-84-3) exert a uricosuric action by inhibiting urate transporter 1 (URAT1). A recent clinical trial indicated that losartan could reduce the level of serum urate in hypertensive patients treated with urate lowering agents, suggesting the different mode of action of losartan from benzbromarone. In the present study, the effect of losartan and benzbromarone on the level of URAT1 mRNA was determined in transfected HEK293 cells. Losartan caused a significant reduction of its mRNA level, whereas it was not affected by benzbromarone. These results indicate that losartan decreases the level of human URAT1 mRNA, which may underlie the uricosuric action of losartan in hypertensive patients treated with serum urate lowering agents.

Identification, isolation and characterization of HCN4-positive pacemaking cells derived from murine embryonic stem cells during cardiac differentiation

BACKGROUND

Development of biological pacemaker is a potential treatment for bradyarrhythmias. Pacemaker cells could be extracted from differentiated embryonic stem (ES) cells based on their specific cell marker hyperpolarization-activated cyclic nucleotide-gated (HCN)4. The goal of this study was to develop a method of identification, isolation, and characterization of pacemaking cells derived from differentiated ES cells with GFP driven by HCN4 promoter.

METHODS AND RESULTS

Polymerase chain reaction (PCR) screening and southern blot analysis revealed that HCN4p-EGFP trans-gene was stably integrated into the chromosome of mouse AB1 ES cells. RT-PCR and immunostaining results showed similar expression of the specific cardiac pacemaker markers of the HCN4p-EGFP ES cells and its parental AB1 ES cell lines. Although HCN4p-EGFP trans-gene may have slight effect on the general mesodermal differentiation, it had no effect on the pluripotency of ES cells, on the transcription of cardiac specific factors and cardiac contractile proteins, and on the capability of ES cells to differentiate into pacemaker cells. Electrophysiological study indicated that HCN4p-GFP-positive cells revealed the spontaneous action potential, which was slowed by the treatment with 2 mM Cs(+), and expressed the hyperpolarization-activeted cation current I(f) encoded by HCN4 gene.

CONCLUSION

By the approach of using stable transfectant of HCN4p-EGFP gene, the identification, isolation, and characterization of ES cell-derived pacemaking cells could be carried out.

Ubiquitin-proteasome system impairment caused by a missense cardiac myosin-binding protein C mutation and associated with cardiac dysfunction in hypertrophic cardiomyopathy

The ubiquitin-proteasome system is responsible for the disappearance of truncated cardiac myosin-binding protein C, and the suppression of its activity contributes to cardiac dysfunction. This study investigated whether missense cardiac myosin-binding protein C gene (MYBPC3) mutation in hypertrophic cardiomyopathy (HCM) leads to destabilization of its protein, causes UPS impairment, and is associated with cardiac dysfunction. Mutations were identified in Japanese HCM patients using denaturing HPLC and sequencing. Heterologous expression was investigated in COS-7 cells as well as neonatal rat cardiac myocytes to examine protein stability and proteasome activity. The cardiac function was measured using echocardiography. Five novel MYBPC3 mutations -- E344K, DeltaK814, Delta2864-2865GC, Q998E, and T1046M -- were identified in this study. Compared with the wild type and other mutations, the E334K protein level was significantly lower, it was degraded faster, it had a higher level of polyubiquination, and increased in cells pretreated with the proteasome inhibitor MG132 (50 microM, 6 h). The electrical charge of its amino acid at position 334 influenced its stability, but E334K did not affect its phosphorylation. The E334K protein reduced cellular 20 S proteasome activity, increased the proapoptotic/antiapoptotic protein ratio, and enhanced apoptosis in transfected Cos-7 cells and neonatal rat cardiac myocytes. Patients carrying the E334K mutation presented significant left ventricular dysfunction and dilation. The conclusion is the missense MYBPC3 mutation E334K destabilizes its protein through UPS and may contribute to cardiac dysfunction in HCM through impairment of the ubiquitin-proteasome system.

Inhibition of beta-adrenergic signaling by intracellular AMP is independent of cell-surface adenosine receptors in rat cardiac cells

We report a novel action of intracellular adenosine monophosphate (AMP) to inhibit beta-adrenergic signaling in isolated rat ventricular myocytes. Extracellular application of adenosine or AMP suppressed isoproterenol (Iso)-induced prolongation of action potential duration (APD). This effect was completely abolished by an A(1)-receptor antagonist, DPCPX. Intracellular application of AMP, but not adenosine, attenuated Iso-induced APD prolongation. Iso-induced increases in the L-type Ca(2+) current (I(Ca,L)) were also inhibited by intracellular AMP. These inhibitory effects were not affected by either DPCPX or glibenclamide. In vitro, AMP directly inhibited PKA activity via binding to its regulatory subunit. These results suggest that intracellular AMP attenuates beta-adrenergic signaling by directly inhibiting PKA activity, independently of A(1)-purinergic receptor.

Delayed onset of beating and decreased expression of T-type Ca2+ channel in mouse ES cell-derived cardiocytes carrying human chromosome 21

The mouse ES cell line hcgp7/#21, which carries a human chromosome 21 (hChr.21), was used as an in vitro model to examine the effects of hChr.21 on cardiomyocyte differentiation. Cardiomyocytes derived from hcgp7/#21 showed a significant delay in the onset of spontaneous beating. The number of Nkx2.5/GFP(+) cardiac progenitor cells was comparable to that in control ES cells and they also expressed comparable mRNA levels for mesodermal markers, cardiac specific transcription factors, contractile proteins, and L-type Ca(2+) channels. However, cells from hcgp7/#21 expressed significantly reduced levels of mRNA for Cav3.1 and Cav3.2, which was consistent with the decreased number of cells expressing T-type Ca(2+) channels and decreased T-type Ca(2+) channel currents. These findings suggest that the presence of human chromosome 21 suppresses expression of T-type Ca(2+) channels in cardiomyocytes during differentiation, which may be responsible for delayed onset of spontaneous beating.