Discovery of S-217622, a Noncovalent Oral SARS-CoV-2 3CL Protease Inhibitor Clinical Candidate for Treating COVID-19

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in millions of deaths and threatens public health and safety. Despite the rapid global spread of COVID-19 vaccines, effective oral antiviral drugs are urgently needed. Here, we describe the discovery of S-217622, the first oral noncovalent, nonpeptidic SARS-CoV-2 3CL protease inhibitor clinical candidate. S-217622 was discovered via virtual screening followed by biological screening of an in-house compound library, and optimization of the hit compound using a structure-based drug design strategy. S-217622 exhibited antiviral activity in vitro against current outbreaking SARS-CoV-2 variants and showed favorable pharmacokinetic profiles in vivo for once-daily oral dosing. Furthermore, S-217622 dose-dependently inhibited intrapulmonary replication of SARS-CoV-2 in mice, indicating that this novel noncovalent inhibitor could be a potential oral agent for treating COVID-19.

Validation of Japanese Bleeding Risk Criteria in Patients After Percutaneous Coronary Intervention and Comparison With Contemporary Bleeding Risk Criteria

Background: The utility of the Japanese version of high bleeding risk (J-HBR) criteria compared with contemporary bleeding risk criteria, including Academic Research Consortium for High Bleeding Risk criteria, has not been fully investigated.

Methods and Results: This study included patients who underwent percutaneous coronary intervention between 2010 and 2019. The J-HBR score was calculated by assigning 1 point for each major criterion and 0.5 points for each minor criterion in the J-HBR criteria. Among 1,643 patients, 1,143 (69.6%) met the J-HBR criteria. Accumulated major bleeding event rates at 1 year were higher among those who met the J-HBR criteria (4.8% vs. 0.6%; P<0.001). J-HBR criteria had higher sensitivity (94.8%) and lower specificity (31.4%) than contemporary bleeding risk criteria in predicting major bleeding. Bleeding events increased with increasing J-HBR score. The C statistic for the J-HBR score for predicting major bleeding at 1 year was 0.75 (95% confidence interval 0.69–0.81), and is comparable to that of other risk scores. In multivariate analysis, of the factors included in J-HBR criteria, chronic kidney disease, heart failure, and active malignancy were associated with major bleeding.

Conclusions: J-HBR criteria identified patients at high bleeding risk with high sensitivity and low specificity. Bleeding risk was closely related to J-HBR score and its individual components. The discriminative ability of the J-HBR score was comparable to that of contemporary bleeding risk scores.

Melanogenic effect of dersimelagon (MT-7117), a novel oral melanocortin 1 receptor agonist

Background

The activation of melanocortin 1 receptor (MC1R) on melanocytes stimulates the production of eumelanin. A tridecapeptide α melanocyte‐stimulating hormone (αMSH) is known to induce skin pigmentation.

Objectives

We characterised the properties of a novel oral MC1R agonist dersimelagon (MT‐7117) with respect to its specific binding to MC1R, downstream signalling and eumelanin production in experimental models.

Methods

The competitive binding and production of intracellular cyclic adenosine 3′, 5′‐monophosphate in cells expressing recombinant melanocortin receptors were examined. A mouse melanoma cell line B16F1 was used for the evaluation of in vitro melanin production. The in vitro activity of MT‐7117 was determined with αMSH and [Nle⁴, D‐Phe⁷]‐αMSH (NDP‐αMSH) as reference comparators. The change of coat colour and skin pigmentation were evaluated after repeat administration of MT‐7117 by oral gavage to C57BL/6J‐A^y/+ mice and cynomolgus monkeys, respectively.

Results

MT‐7117 showed the highest affinity for human MC1R compared to the other melanocortin receptors evaluated and agonistic activity for human, cynomolgus monkey and mouse MC1R, with EC₅₀ values in the nanomolar range. In B16F1 cells, MT‐7117 increased melanin production in a concentration‐dependent manner. In vivo, MT‐7117 (≥0.3 mg/kg/day p.o.) significantly induced coat colour darkening in mice. MT‐7117 (≥1 mg/kg/day p.o.) induced significant skin pigmentation in monkeys and complete reversibility was observed after cessation of its administration.

Conclusions

MT‐7117 is a novel oral MC1R agonist that induces melanogenesis in vitro and in vivo, suggesting its potential application for the prevention of phototoxic reactions in patients with photodermatoses, such as erythropoietic protoporphyria and X‐linked protoporphyria.

Characterization of the In Vitro and In Vivo Efficacy of Baloxavir Marboxil against H5 Highly Pathogenic Avian Influenza Virus Infection

Human infections caused by the H5 highly pathogenic avian influenza virus (HPAIV) sporadically threaten public health. The susceptibility of HPAIVs to baloxavir acid (BXA), a new class of inhibitors for the influenza virus cap-dependent endonuclease, has been confirmed in vitro, but it has not yet been fully characterized. Here, the efficacy of BXA against HPAIVs, including recent H5N8 variants, was assessed in vitro. The antiviral efficacy of baloxavir marboxil (BXM) in H5N1 virus-infected mice was also investigated. BXA exhibited similar in vitro activities against H5N1, H5N6, and H5N8 variants tested in comparison with seasonal and other zoonotic strains. Compared with oseltamivir phosphate (OSP), BXM monotherapy in mice infected with the H5N1 HPAIV clinical isolate, the A/Hong Kong/483/1997 strain, also caused a significant reduction in viral titers in the lungs, brains, and kidneys, thereby preventing acute lung inflammation and reducing mortality. Furthermore, compared with BXM or OSP monotherapy, combination treatments with BXM and OSP using a 48-h delayed treatment model showed a more potent effect on viral replication in the organs, accompanied by improved survival. In conclusion, BXM has a potent antiviral efficacy against H5 HPAIV infections.

Synthesis and anti-dengue virus activity of 5-ethynylimidazole-4-carboxamide (EICA) nucleotide prodrugs

We previously showed that 5-ethynyl-(1-β-D-ribofuranosyl)imidazole-4-carboxamide (1; EICAR) is a potent anti-dengue virus (DENV) compound but is cytotoxic to some cell lines, while its 4-thio derivative, 5-ethynyl-(4-thio-1-β-D-ribofuranosyl)imidazole-4-carboxamide (2; 4'-thioEICAR), has less cytotoxicity but also less anti-DENV activity. Based on the hypothesis that the lower anti-DENV activity of 2 is due to reduced susceptibility to phosphorylation by cellular kinase(s), we investigated whether a monophosphate prodrug of 2 can improve its activity. Here, we first prepared two types of prodrug of 1, which revealed that the S-acyl-2-thioethyl (SATE) prodrug had stronger anti-DENV activity than the aryloxyphosphoramidate (so-called ProTide) prodrug. Based on these findings, we next prepared the SATE prodrug of 4'-thioEICAR 18. As expected, the resulting 18 showed potent anti-DENV activity, which was comparable to that of 1; however, its cytotoxicity was also increased relative to 2. Our findings suggest that prodrugs of 4'-thioribonucleoside derivatives such as EICAR (1) represent an effective approach to developing potent biologically active compounds; however, the balance between antiviral activity and cytotoxicity remains to be addressed.

Application of Acoustic Ejection MS System to High-Throughput Screening for SARS-CoV-2 3CL Protease Inhibitors

Mass spectrometry is a powerful methodology for chemical screening to directly quantify substrates and products of enzymes, but its low throughput has been an issue. Recently, an acoustic liquid-handling apparatus (Echo^®) used for rapid nano-dispensing has been coupled to a high-sensitivity mass spectrometer to create the Echo^® MS system, and we applied this system to screening of SARS-CoV-2 3CL protease inhibitors. Primary screening of 32,033 chemical samples was completed in 12 hours. Among the hits showing selective, dose-dependent 3CL-inhibitory activity, 8 compounds showed antiviral activity in cell-based assay.

Air-liquid interphase culture confers SARS-CoV-2 susceptibility to A549 alveolar epithelial cells

The human lung cell A549 is susceptible to infection with a number of respiratory viruses. However, A549 cells are resistant to Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) infection in conventional submerged culture, and this would appear to be due to low expression levels of the SARS-CoV-2 entry receptor: angiotensin-converting enzyme-2 (ACE2). Here, we examined SARS-CoV-2 susceptibility to A549 cells after adaptation to air-liquid interface (ALI) culture. A549 cells in ALI culture yielded a layer of mucus on their apical surface, exhibited decreased expression levels of the proliferation marker KI-67 and intriguingly became susceptible to SARS-CoV-2 infection. We found that A549 cells increased the endogenous expression levels of ACE2 and TMPRSS2 following adaptation to ALI culture conditions. Camostat, a TMPRSS2 inhibitor, reduced SARS-CoV-2 infection in ALI-cultured A549 cells. These findings indicate that ALI culture switches the phenotype of A549 cells from resistance to susceptibility to SARS-CoV-2 infection through upregulation of ACE2 and TMPRSS2.

5-Hydroxymethyltubercidin exhibits potent antiviral activity against flaviviruses and coronaviruses, including SARS-CoV-2

Newly emerging or re-emerging viral infections continue to cause significant morbidity and mortality every year worldwide, resulting in serious effects on both health and the global economy. Despite significant drug discovery research against dengue viruses (DENVs) and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), no fully effective and specific drugs directed against these viruses have been discovered. Here, we examined the anti-DENV activity of tubercidin derivatives from a compound library from Hokkaido University and demonstrated that 5-hydroxymethyltubercidin (HMTU, HUP1108) possessed both potent anti-flavivirus and anti-coronavirus activities at submicromolar levels without significant cytotoxicity. Furthermore, HMTU inhibited viral RNA replication and specifically inhibited replication at the late stages of the SARS-CoV-2 infection process. Finally, we demonstrated that HMTU 5′-triphosphate inhibited RNA extension catalyzed by the viral RNA-dependent RNA polymerase. Our findings suggest that HMTU has the potential of serving as a lead compound for the development of a broad spectrum of antiviral agents, including SARS-CoV-2.

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We identified tubercidin derivatives as broad-spectrum antiviral compounds

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HMTU exhibited potent antiviral activity against flaviviruses and coronaviruses

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HMTU specifically inhibited replication at a late stage of the viral infection process

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HMTU 5′-triphosphate inhibited RNA extension catalyzed by viral RdRp

A SARS-CoV-2 antibody broadly neutralizes SARS-related coronaviruses and variants by coordinated recognition of a virus-vulnerable site

Potent neutralizing SARS-CoV-2 antibodies often target the spike protein receptor-binding site (RBS), but the variability of RBS epitopes hampers broad neutralization of multiple sarbecoviruses and drifted viruses. Here, using humanized mice, we identified an RBS antibody with a germline V_H gene that potently neutralized SARS-related coronaviruses, including SARS-CoV and SARS-CoV-2 variants. X-ray crystallography revealed coordinated recognition by the heavy chain of non-RBS conserved sites and the light chain of RBS with a binding angle mimicking the angiotensin-converting enzyme 2 (ACE2) receptor. The minimum footprints in the hypervariable region of RBS contributed to the breadth of neutralization, which was enhanced by immunoglobulin G3 (IgG3) class switching. The coordinated binding resulted in broad neutralization of SARS-CoV and emerging SARS-CoV-2 variants of concern. Low-dose therapeutic antibody treatment in hamsters reduced the virus titers and morbidity during SARS-CoV-2 challenge. The structural basis for broad neutralizing activity may inform the design of a broad spectrum of therapeutics and vaccines.

Attenuated infection by a Pteropine orthoreovirus isolated from an Egyptian fruit bat in Zambia

Background

Pteropine orthoreovirus (PRV) is an emerging bat-borne zoonotic virus that causes severe respiratory illness in humans. Although PRVs have been identified in fruit bats and humans in Australia and Asia, little is known about the prevalence of PRV infection in Africa. Therefore, this study performed an PRV surveillance in fruit bats in Zambia.

Methods

Egyptian fruit bats (Rousettus aegyptiacus, n = 47) and straw-colored fruit bats (Eidolon helvum, n = 33) captured in Zambia in 2017–2018 were screened for PRV infection using RT-PCR and serum neutralization tests. The complete genome sequence of an isolated PRV strain was determined by next generation sequencing and subjected to BLAST and phylogenetic analyses. Replication capacity and pathogenicity of the strain were investigated using Vero E6 cell cultures and BALB/c mice, respectively.

Results

An PRV strain, tentatively named Nachunsulwe-57, was isolated from one Egyptian fruit bat. Serological assays demonstrated that 98% of sera (69/70) collected from Egyptian fruit bats (n = 37) and straw-colored fruit bats (n = 33) had neutralizing antibodies against PRV. Genetic analyses revealed that all 10 genome segments of Nachunsulwe-57 were closely related to a bat-derived Kasama strain found in Uganda. Nachunsulwe-57 showed less efficiency in viral growth and lower pathogenicity in mice than another PRV strain, Miyazaki-Bali/2007, isolated from a patient.

Conclusions

A high proportion of Egyptian fruit bats and straw-colored fruit bats were found to be seropositive to PRV in Zambia. Importantly, a new PRV strain (Nachunsulwe-57) was isolated from an Egyptian fruit bat in Zambia, which had relatively weak pathogenicity in mice. Taken together, our findings provide new epidemiological insights about PRV infection in bats and indicate the first isolation of an PRV strain that may have low pathogenicity to humans.

Pteropine orthoreovirus (PRV) is a causative agent of acute respiratory illness in humans in tropical and sub-tropical regions in Southeast Asia. PRVs have been originally isolated from fruit bats, and it is assumed that PRVs spread to humans by both bat-to-human and human-to-human transmission. Recently, an PRV was also detected from a fruit bat in the Afrotropical region and might potentially cause an emerging infection of the bat-borne zoonotic virus in Africa. However, little is known about the prevalence of PRV infection in Africa. In this study, we demonstrated the high prevalence of PRV infection in bat populations in Zambia and isolated a new strain of PRV from Egyptian fruit bats. In addition, we found that the bat-derived PRV strain had lower pathogenicity in mice than a human-derived PRV strain isolated from a patient in Southeast Asia. Our findings provide new epidemiological information about PRV in fruit bats in the Afrotropical region and indicate the first isolation of an PRV strain that may cause attenuated infection in humans.

Pharmacokinetic and pharmacodynamic analysis of baloxavir marboxil, a novel cap-dependent endonuclease inhibitor, in a murine model of influenza virus infection

Background

Baloxavir acid, the active form of the orally available prodrug baloxavir marboxil, is a novel cap-dependent endonuclease inhibitor of influenza virus. Baloxavir marboxil has been shown to rapidly reduce virus titres compared with oseltamivir in clinical studies.

Objectives

We investigated the relationship between pharmacokinetic (PK) parameters and antiviral activity of baloxavir acid based on virus titre reduction in lungs of infected mice.

Methods

BALB/c mice infected with a sub-lethal dose of influenza A(H1N1), A(H1N1)pdm09, A(H3N2) or type B virus were treated on day 5 with oral baloxavir marboxil (0.5–50 mg/kg q12h), subcutaneous baloxavir acid (0.25–8 mg/kg/day), oseltamivir phosphate (5 or 50 eq mg/kg q12h) or other antivirals for 1 day. Lung virus titres were assessed 24 h after initial antiviral dosing. PK testing was performed at up to 24 h post-dosing of baloxavir marboxil or baloxavir acid in A/WSN/33-infected mice and the PK/pharmacodynamic (PD) relationship was evaluated for baloxavir acid.

Results

Oral baloxavir marboxil administration showed dose-dependent virus titre reductions in lungs of mice infected with the different types/subtypes of influenza viruses 24 h post-dosing. Baloxavir marboxil at 15 mg/kg q12h resulted in ≥100-fold and ≥10-fold reductions in influenza A and B virus titres, respectively, compared with oseltamivir phosphate. PK/PD analysis showed that the plasma concentration at the end of the dosing interval (C_τ) or the plasma concentration at 24 h after initial dosing (C₂₄) was the PK parameter predicting the virus titres at 24 h post-dosing of baloxavir acid.

Conclusions

PK/PD analysis of baloxavir acid based on virus titre reduction in this mouse model could be helpful in predicting and maximizing virological outcomes in clinical settings.

New method of recording the functional activity pattern of the buccinator from the mucosal surface

OBJECTIVES

The buccinator (BUC) is an important muscle for oral function. Since it lies deep in the facial skin, recording its activity is difficult; thus, studies on its function are limited. We developed a method to access the deep facial muscles from the mucosal side. The aim of this study was to test the reliability of the new recording method for the BUC and to investigate the BUC behavior in typical facial functions.

METHODS

To evaluate the new method, BUC activities were recorded simultaneously with a gel-type electrode on the skin and the newly developed surface electrode on the buccal mucosa. Electromyographic (EMG) activities in function, such as chewing and swallowing, along with the activities of the lower orbicularis oris (OO), zygomaticus major, masseter, and digastric muscles, were compared using the two recording methods. EMG activities among various tasks were compared using normalized values based on those obtained during maximum lip closure (MaxLC).

RESULTS

The new surface electrode was made of gold plates on a thin plastic fixed to a stainless-steel wire frame and weighed less than 1 g. The BUC activity recorded from the mucosa was the highest during a corner-pulling task and was low during clenching. The BUC was active during MaxLC, similar to the OO, and the BUC activity pattern among tasks recorded from the mucosa was identical to that reported by previous studies using intramuscular electrodes. The new electrode evaluated the BUC activities quantitatively, and the recordings by the new electrode were free from contamination.

CONCLUSIONS

The findings of this study confirmed the reliability of the new BUC recording method. It could be easily placed correctly within seconds, without the need for cleansing or sterilizing the skin. The BUC and OO were active during a MaxLC task, indicating that the BUC assists lip closure by pulling the corners of the mouth. The basic facial functions evaluated, including chewing, were similar to those studied by intramuscular electrodes.

Sesame lignans suppress age-related disorders of the kidney in mice

OBJECTIVE

Sesamin is a functional ingredient in sesame (Sesamum indicum) seeds and has many physiological effects. This study investigated whether sesame lignans, sesamin and episesamin (1:1), can suppress age-related disorders of the kidney.

MATERIALS AND METHODS

Twenty-month-old mice were divided into three groups, and each group received a regular diet (O-C), diet containing sesame lignans (O-SE), and diet containing sesame lignans and α-tocopherol (VE; O-SE+VE), respectively, for 5 months. Six-month-old young mice (Y-C) were compared to the older mice.

RESULTS

Renal lipofuscin deposition was increased in the O-C group compared to that in the Y-C group and its deposition with aging was significantly decreased in both O-SE and O-SE+VE groups. Plasma blood urea nitrogen levels in the O-C group increased compared to those in the Y-C group; however, those in both O-SE and O-SE+VE groups did not differ from those in the Y-C group. The number of podocytes in the O-C group decreased compared to that in the Y-C group and this effect was attenuated in the O-SE and O-SE+VE groups. The effect was strongest in the O-SE+VE group. Histological examinations showed that glomerular hypertrophy accompanied by mesangial hyperplasia and renal tubular degeneration was less severe in the O-SE and O-SE+VE groups than in the O-C group. Moreover, age-related increases in the mRNA expression of NADPH oxidase- and inflammation-related genes, including p67phox, p40phox, TNFα, and IL-6, in the kidney were suppressed in the O-SE and O-SE+VE groups.

CONCLUSIONS

Sesame lignans might be useful to suppress age-related kidney disorders, and these effects could be enhanced with VE.

TMPRSS11D and TMPRSS13 Activate the SARS-CoV-2 Spike Protein

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) utilizes host proteases, including a plasma membrane-associated transmembrane protease, serine 2 (TMPRSS2) to cleave and activate the virus spike protein to facilitate cellular entry. Although TMPRSS2 is a well-characterized type II transmembrane serine protease (TTSP), the role of other TTSPs on the replication of SARS-CoV-2 remains to be elucidated. Here, we have screened 12 TTSPs using human angiotensin-converting enzyme 2-expressing HEK293T (293T-ACE2) cells and Vero E6 cells and demonstrated that exogenous expression of TMPRSS11D and TMPRSS13 enhanced cellular uptake and subsequent replication of SARS-CoV-2. In addition, SARS-CoV-1 and SARS-CoV-2 share the same TTSPs in the viral entry process. Our study demonstrates the impact of host TTSPs on infection of SARS-CoV-2, which may have implications for cell and tissue tropism, for pathogenicity, and potentially for vaccine development.

SARS-CoV-2 variants with mutations at the S1/S2 cleavage site are generated in vitro during propagation in TMPRSS2-deficient cells

The spike (S) protein of Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) binds to a host cell receptor which facilitates viral entry. A polybasic motif detected at the cleavage site of the S protein has been shown to broaden the cell tropism and transmissibility of the virus. Here we examine the properties of SARS-CoV-2 variants with mutations at the S protein cleavage site that undergo inefficient proteolytic cleavage. Virus variants with S gene mutations generated smaller plaques and exhibited a more limited range of cell tropism compared to the wild-type strain. These alterations were shown to result from their inability to utilize the entry pathway involving direct fusion mediated by the host type II transmembrane serine protease, TMPRSS2. Notably, viruses with S gene mutations emerged rapidly and became the dominant SARS-CoV-2 variants in TMPRSS2-deficient cells including Vero cells. Our study demonstrated that the S protein polybasic cleavage motif is a critical factor underlying SARS-CoV-2 entry and cell tropism. As such, researchers should be alert to the possibility of de novo S gene mutations emerging in tissue-culture propagated virus strains.

Efficacy of cardiac rehabilitation with motion assistance from wearable cyborg hybrid assistive limb in patients with chronic heart failure: a randomized controlled trial

Background

Recent Cochrane Systematic Review suggested that the participation in cardiac rehabilitation is associated with approximately 20% lower cardiovascular mortality and morbidity. Exercise therapy is the key component of cardiac rehabilitation programs. In recent years, innovative technologies have been introduced into the field of rehabilitation, and a typical example is the wearable cyborg Hybrid Assistive Limb (HAL). The wearable cyborg HAL provides motion assistance based on detection of bioelectrical signals on the skin surface when muscle forces are generated. The lumbar-type HAL is expected to expand the therapeutic options for severe cardiac patients who have difficulty in performing usual cardiac rehabilitation programs, such as bicycle pedaling or walking.

Purpose

We aim to compare the efficacy of exercise therapy performed with motion assistance from a lumbar-type HAL versus conventional training (sit-to-stand exercise without HAL) in patients with chronic heart failure.

Methods

This clinical trial is a randomized, non-blinded, and controlled study. Twenty-eight heart failure patients (73.1±13.8 years) who have difficulty in walking at the usual walking speed of healthy subjects were randomly assigned to 2 groups (HAL group or control group) with a 1:1 allocation ratio and performed sit-to stand exercise either with HAL or without HAL for 5 to 30 minutes once a day, and 6 to 10 days during the study period. The brain natriuretic peptide (BNP), isometric knee extensor strength, standing ability (30-seconds chair-stand test: CS-30), short physical performance battery (SPPB) and 6-minute walking distance (6MWD) were measured before and after the completion of cardiac rehabilitation. Cardiac events such as death, re-hospitalization, myocardial infarction and worsening of angina pectoris and heart failure during 1 year after discharge were evaluated.

Results

There was no significant difference in the number of days of exercise therapy between the two groups. BNP, SPPB and 6MWD were improved in both groups. In the HAL group, the isometric knee extensor strength (0.29±0.11 vs 0.35±0.11 kgf/kg, p=0.003) significantly improved and CS-30 (5.5±5.1 vs 8.2±5.3, p=0.054) tended to improve. However, in the control group, either the isometric knee extensor strength (0.35±0.11 vs 0.36±0.14 kgf/kg, p=0.424) or CS-30 (6.0±4.3 vs 9.2±6.2, p=0.075) did not significantly change. HAL group showed significantly more improvement in the isometric knee extensor strength than control group (p=0.045). Cardiac events occurred in 20% in the HAL group and 43% in the control group.

Conclusion

The improvement in isometric knee extensor strength with the assistance from lumbar-type HAL suggests that exercise therapy using this device may be useful in chronic heart failure patients with flail or sarcopenia, a strong poor prognostic factor in these patients.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This work was supported in part by a grant-in-aid for Scientific Research from the Ministry of Education, Science, and Culture of Japan (JSPS KAKENHI grant number JP17K09485) and funded by the ImPACT Program of the Council for Science, Technology and Innovation (Cabinet Office, Government of Japan) (grant number 2017-PM05-03-01).

Impact of coronary plaque characteristics on periprocedural myocardial injury after elective percutaneous coronary intervention -MDCT and CMR analysis-

Background

Percutaneous coronary intervention (PCI) is often complicated by periprocedural myocardial injury (PMI) manifested by elevated cardiac biomarkers. The occurrence of PMI has been shown to be associated with worse clinical outcome over short- and long-term.

Purpose

We performed multidetector computed tomography (MDCT) and cardiac magnetic resonance imaging (CMR) to evaluate the relationship between culprit plaque characteristics and PMI.

Methods

A total of 90 patients who underwent elective PCI were underwent CMR and multidetector coronary tomography before PCI. The high intensity plaque (HIP) on CMR was defined as a coronary plaque to myocardium signal intensity ratio (PMR) of &gt;1.4. The plaque characteristics and the presence of napkin-ring sign (NRS) were analyzed on MDCT. PMI was defined as an increase in cardiac Troponin T levels to more than 5 times the upper limit of normal at 24 h after PCI. Patients were divided into 2 groups according to the presence (Group I, n=26) or absence (Group II, n=64) of PMI.

Results

Spotty calcification, positive remodeling, low attenuation plaque and NRS on MDCT were significantly more observed in Group I than in Group II. HIP on CMR was significantly more observed in Group I than in Group II. In the multivariable logistic regression analysis, the presence of NRS and HIP were significantly independent predictors of PMI (odds ratio (OR) 4.82, 95% confidence interval 1.13–20.60, P=0.034 and OR 3.66, 95% CI 1.09–12.30, P=0.036, respectively). Moreover, for prediction of PMI, NRS and HIP showed a high positive predictive value of 81%, and their absence showed a high negative predictive value of 91%.

Conclusions

MDCT and CMR may play an important role in detecting which lesions are high risks for myocardial necrosis after PCI in elective coronary stenting.

Funding Acknowledgement

Type of funding source: None

Association of coronary high-intensity plaque on T1-weighted magnetic resonance imaging and circulating malondialdehyde-modified low-density lipoprotein levels with cardiac events

Background

Although elevated oxidized low-density lipoprotein could play critical roles in vulnerable plaque, there are no studies that compared coronary high-intensity plaque (HIP) on non-contrast T1-weighted magnetic resonance imaging (T1WI_MRI) and circulating malondialdehyde-modified low-density lipoprotein (MDA-LDL) levels for the prediction of cardiac events.

Methods and results

A total of 139 patients with coronary artery stenosis (&gt;70%) were examined with non-contrast T1WI using a 1.5-T MRI (HIP: n=63, non-HIP: n=76). Scheduled percutaneous coronary intervention (PCI) for culprit lesions was performed within 48 h after MRI. HIP was defined as a signal intensity of coronary plaque to cardiac muscle ratio (PMR) of ≥1.4. At admission, circulating levels of MDA-LDL and other lipid-related markers were measured. We evaluated the subsequent cardiac events, which were defined as major adverse cardiac events (MACE; cardiac death, myocardial infarction, and/or ischemia-driven PCI) during follow-up periods (5.6±1.3 years). Circulating MDA-LDL levels were significantly higher in patients with HIP than in those without HIP (p&lt;0.0001). MDA-LDL levels were significantly correlated with PMR (r=0.490, p&lt;0.0001). In multivariable logistic regression analysis, MDA-LDL levels were independently associated with the presence of HIP (OR 1.05; 95% CI, 1.02–1.08, p&lt;0.0001). The incidence of MACE was significantly higher in patients with HIP (27%) than in those without HIP (5%; p=0.011 by the log-rank test). In the multivariable Cox proportional hazard analysis, the MDA-LDL levels (HR 1.03; 95% CI:1.01–1.05, p=0.007) and PMR (HR 2.39; 95% CI:1.19–4.65, p=0.016) were significantly associated with MACE. For MACE prediction, the C-statistic values for MDA-LDL, PMR, and PMR+MDA-LDL were 0.724, 0.791, and 0.800, respectively. Compared with MDA-LDL alone, the addition of PMR to MDA-LDL increased the net reclassification improvement by 0.78 (p=0.012).

Conclusions

MDA-LDL levels might be associated with the presence of HIP in patients with coronary artery disease. Furthermore, adding PMR to MDA-LDL levels markedly improved MACE prediction.

Funding Acknowledgement

Type of funding source: None

Pulmonary vein isolation for atrial fibrillation patients with reduced left ventricular ejection fraction

 

Background/Introduction Pulmonary vein isolation (PVI) is a cornerstone of curable treatment for atrial fibrillation (AF). Left ventricular (LV) ejection fraction (EF) occasionally improves after PVI in AF patients with reduced LVEF (rEF), the mechanism of which is not fully understood. CASTLE-AF trial have demonstrated that PVI with radiofrequency (RF) catheter for AF patients with rEF can reduce their mortality and heart failure. Nevertheless there are limited data about the clinical outcome of the PVI for patients with impaired LV function.

Purpose

This study was to evaluate the efficacy of PVI and improvement of LVEF after the procedure in AF patients with rEF.

Methods

A total of 2709 consecutive AF patients (age 65±39 y/o, male 67%) underwent their first PVI with cryoballoon or RF catheter in our facility from April 2014 to March 2019, and retrospectively analyzed. All the patients underwent echocardiogram before and half to one year after the procedure. Patients with LVEF under 40% before the PVI were selected (n=111) and divided into two groups based on whether there were specific etiologies of LV function impairment (group A) or not (group B).

Results

There were no significant difference in mean LVEF between group A (n=40) and group B (n=71) (32±6% vs 33±6%, p=0.12). The major etiology of rEF in group A were old myocardial infarction (n=20, 18%), hypertensive heart disease (n=6, 5.4%), and dilated cardiomyopathy (n=5, 4.5%). After mean follow-up of 2.7 years, there were no significant difference in clinical outcome after the procedure between two groups (1-year Kaplan–Meier event rate estimates; 72.2% vs 72.9%; p=0.85). The change amounts of LVEF after the PVI were significantly higher in group B (20±14%) compared to group A (2±10%) (p&lt;0.001). Multivariable Cox regression analysis revealed that age was the independent significant predictors of EF improvement over 10% in group B (p=0.048).

Conclusions

In AF patients with reduced LVEF, there were no significant difference in efficacy of PVI between those who have specific etiologies of LV function impairment other than AF and who have not. The improvement of LVEF after PVI was significantly larger in patients without specific etiologies compared to those with.

Funding Acknowledgement

Type of funding source: None