RENEB Inter-Laboratory Comparison 2021: Inter-Assay Comparison of Eight Dosimetry Assays

Tools for radiation exposure reconstruction are required to support the medical management of radiation victims in radiological or nuclear incidents. Different biological and physical dosimetry assays can be used for various exposure scenarios to estimate the dose of ionizing radiation a person has absorbed. Regular validation of the techniques through inter-laboratory comparisons (ILC) is essential to guarantee high quality results. In the current RENEB inter-laboratory comparison, the performance quality of established cytogenetic assays [dicentric chromosome assay (DCA), cytokinesis-block micronucleus assay (CBMN), stable chromosomal translocation assay (FISH) and premature chromosome condensation assay (PCC)] was tested in comparison to molecular biological assays [gamma-H2AX foci (gH2AX), gene expression (GE)] and physical dosimetry-based assays [electron paramagnetic resonance (EPR), optically or thermally stimulated luminescence (LUM)]. Three blinded coded samples (e.g., blood, enamel or mobiles) were exposed to 0, 1.2 or 3.5 Gy X-ray reference doses (240 kVp, 1 Gy/min). These doses roughly correspond to clinically relevant groups of unexposed to low exposed (0-1 Gy), moderately exposed (1-2 Gy, no severe acute health effects expected) and highly exposed individuals (>2 Gy, requiring early intensive medical care). In the frame of the current RENEB inter-laboratory comparison, samples were sent to 86 specialized teams in 46 organizations from 27 nations for dose estimation and identification of three clinically relevant groups. The time for sending early crude reports and more precise reports was documented for each laboratory and assay where possible. The quality of dose estimates was analyzed with three different levels of granularity, 1. by calculating the frequency of correctly reported clinically relevant dose categories, 2. by determining the number of dose estimates within the uncertainty intervals recommended for triage dosimetry (±0.5 Gy or ±1.0 Gy for doses <2.5 Gy or >2.5 Gy), and 3. by calculating the absolute difference (AD) of estimated doses relative to the reference doses. In total, 554 dose estimates were submitted within the 6-week period given before the exercise was closed. For samples processed with the highest priority, earliest dose estimates/categories were reported within 5-10 h of receipt for GE, gH2AX, LUM, EPR, 2-3 days for DCA, CBMN and within 6-7 days for the FISH assay. For the unirradiated control sample, the categorization in the correct clinically relevant group (0-1 Gy) as well as the allocation to the triage uncertainty interval was, with the exception of a few outliers, successfully performed for all assays. For the 3.5 Gy sample the percentage of correct classifications to the clinically relevant group (≥2 Gy) was between 89-100% for all assays, with the exception of gH2AX. For the 1.2 Gy sample, an exact allocation to the clinically relevant group was more difficult and 0-50% or 0-48% of the estimates were wrongly classified into the lowest or highest dose categories, respectively. For the irradiated samples, the correct allocation to the triage uncertainty intervals varied considerably between assays for the 1.2 Gy (29-76%) and 3.5 Gy (17-100%) samples. While a systematic shift towards higher doses was observed for the cytogenetic-based assays, extreme outliers exceeding the reference doses 2-6 fold were observed for EPR, FISH and GE assays. These outliers were related to a particular material examined (tooth enamel for EPR assay, reported as kerma in enamel, but when converted into the proper quantity, i.e. to kerma in air, expected dose estimates could be recalculated in most cases), the level of experience of the teams (FISH) and methodological uncertainties (GE). This was the first RENEB ILC where everything, from blood sampling to irradiation and shipment of the samples, was organized and realized at the same institution, for several biological and physical retrospective dosimetry assays. Almost all assays appeared comparably applicable for the identification of unexposed and highly exposed individuals and the allocation of medical relevant groups, with the latter requiring medical support for the acute radiation scenario simulated in this exercise. However, extreme outliers or a systematic shift of dose estimates have been observed for some assays. Possible reasons will be discussed in the assay specific papers of this special issue. In summary, this ILC clearly demonstrates the need to conduct regular exercises to identify research needs, but also to identify technical problems and to optimize the design of future ILCs.

RENEB Inter-Laboratory Comparison 2021: The FISH-Based Translocation Assay

Translocation analysis using fluorescence in situ hybridization (FISH) is the method of choice for dose assessment in case of chronic or past exposures to ionizing radiation. Although it is a widespread technique, unlike dicentrics, the number of FISH-based inter-laboratory comparisons is small. For this reason, although the current Running the European Network of Biological and Physical retrospective Dosimetry (RENEB) inter-laboratory comparison 2021 was designed as a fast response to a real emergency scenario, it was considered a good opportunity to perform an inter-laboratory comparison using the FISH technique to gain further experience. The Bundeswehr Institute of Radiobiology provided peripheral blood samples from one healthy human volunteer. Three test samples were irradiated with blinded doses of 0, 1.2, and 3.5 Gy, respectively. Samples were then sent to the seven participating laboratories. The FISH technique was applied according to the standard procedure of each laboratory. Both, the frequency of translocations and the estimated dose for each sample were sent to the coordinator using a special scoring sheet for FISH. All participants sent their results in due time. However, although it was initially requested to send the results based on the full analysis, evaluating 500 equivalent cells, most laboratories only sent the results based on triage, with a smaller number of analyzed cells. In the triage analysis, there was great heterogeneity in the number of equivalent cells scored. On the contrary, for the full analysis, this number was more homogeneous. For all three samples, one laboratory showed outlier yields compared to the other laboratories. Excluding these results, in the triage analysis, the frequency of translocations in sample no. 1 ranged from 0 to 0.013 translocations per cell, and for samples no. 2 and no. 3 the genomic mean frequency were 0.27 ± 0.03 and 1.47 ± 0.14, with a coefficient of variation of 0.29 and 0.23 respectively. Considering only results obtained in the triage analysis for sample no. 1, all laboratories, except one, classified this sample as the non-irradiated one. For sample no. 2, excluding the outlier value, the mean reported dose was 1.74 ± 0.16 Gy indicating a mean deviation of about 0.5 Gy to the delivered dose of 1.2 Gy. For sample no. 3 the mean dose estimated was 4.21 ± 0.21 Gy indicating a mean deviation of about 0.7 Gy to the delivered dose of 3.5 Gy. In the frame of RENEB, this is the second FISH-based inter-laboratory comparison. The whole exercise was planned as a response to an emergency, therefore, a triage analysis was requested for all the biomarkers except for FISH. Although a full analysis was initially requested for FISH, most of the laboratories reported only a triage-based result. The main reason is that it was not clearly stated what was required before starting the exercise. Results show that most of the laboratories successfully discriminated unexposed and irradiated samples from each other without any overlap. A good agreement in the observed frequencies of translocations was observed but there was a tendency to overestimate the delivered doses. Efforts to improve the harmonization of this technique and subsequent exercises to elucidate the reason for this trend should be promoted.

RENEB Inter-Laboratory Comparison 2021: The Dicentric Chromosome Assay

After large-scale radiation accidents where many individuals are suspected to be exposed to ionizing radiation, biological and physical retrospective dosimetry assays are important tools to aid clinical decision making by categorizing individuals into unexposed/minimally, moderately or highly exposed groups. Quality-controlled inter-laboratory comparisons of simulated accident scenarios are regularly performed in the frame of the European legal association RENEB (Running the European Network of Biological and Physical retrospective Dosimetry) to optimize international networking and emergency readiness in case of large-scale radiation events. In total 33 laboratories from 22 countries around the world participated in the current RENEB inter-laboratory comparison 2021 for the dicentric chromosome assay. Blood was irradiated in vitro with X rays (240 kVp, 13 mA, ∼75 keV, 1 Gy/min) to simulate an acute, homogeneous whole-body exposure. Three blood samples (no. 1: 0 Gy, no. 2: 1.2 Gy, no. 3: 3.5 Gy) were sent to each participant and the task was to culture samples, to prepare slides and to assess radiation doses based on the observed dicentric yields from 50 manually or 150 semi-automatically scored metaphases (triage mode scoring). Approximately two-thirds of the participants applied calibration curves from irradiations with γ rays and about 1/3 from irradiations with X rays with varying energies. The categorization of the samples in clinically relevant groups corresponding to individuals that were unexposed/minimally (0-1 Gy), moderately (1-2 Gy) or highly exposed (>2 Gy) was successfully performed by all participants for sample no. 1 and no. 3 and by ≥74% for sample no. 2. However, while most participants estimated a dose of exactly 0 Gy for the sham-irradiated sample, the precise dose estimates of the samples irradiated with doses >0 Gy were systematically higher than the corresponding reference doses and showed a median deviation of 0.5 Gy (sample no. 2) and 0.95 Gy (sample no. 3) for manual scoring. By converting doses estimated based on γ-ray calibration curves to X-ray doses of a comparable mean photon energy as used in this exercise, the median deviation decreased to 0.27 Gy (sample no. 2) and 0.6 Gy (sample no. 3). The main aim of biological dosimetry in the case of a large-scale event is the categorization of individuals into clinically relevant groups, to aid clinical decision making. This task was successfully performed by all participants for the 0 Gy and 3.5 Gy samples and by 74% (manual scoring) and 80% (semi-automatic scoring) for the 1.2 Gy sample. Due to the accuracy of the dicentric chromosome assay and the high number of participating laboratories, a systematic shift of the dose estimates could be revealed. Differences in radiation quality (X ray vs. γ ray) between the test samples and the applied dose effect curves can partly explain the systematic shift. There might be several additional reasons for the observed bias (e.g., donor effects, transport, experimental conditions or the irradiation setup) and the analysis of these reasons provides great opportunities for future research. The participation of laboratories from countries around the world gave the opportunity to compare the results on an international level.

Effects of prior osteoporosis treatment on the treatment response of romosozumab followed by denosumab in patients with postmenopausal osteoporosis

In patients with postmenopausal osteoporosis, prior osteoporosis treatment affected the bone mineral density increase of following treatment with 12 months of romosozumab, although it did not affect that of following treatment with 12 months of denosumab after romosozumab.

PURPOSE

To investigate the effects of prior osteoporosis treatment on the response to treatment with romosozumab (ROMO) followed by denosumab (DMAb) in patients with postmenopausal osteoporosis.

METHODS

In this prospective, observational, multicenter study, treatment-naïve patients (Naïve; n = 55) or patients previously treated with bisphosphonates (BP; n = 37), DMAb (DMAb; n = 45) or teriparatide (TPTD; n = 17) (mean age, 74.6 years; T-scores of the lumbar spine [LS] - 3.2 and total hip [TH] - 2.6) were switched to ROMO for 12 months, followed by DMAb for 12 months. Bone mineral density (BMD) and serum bone turnover markers were evaluated for 24 months.

RESULTS

A BMD increase was observed at 12 and 24 months in the following patients: Naïve (18.2% and 22.0%), BP (10.2% and 12.1%), DMAb (6.6% and 9.7%), and TPTD (10.8% and 15.0%) (P < 0.001 between the groups at both 12 and 24 months) in LS and Naïve (5.5% and 8.3%), BP (2.9% and 4.1%), DMAb (0.6% and 2.2%), and TPTD (4.3% and 5.4%) (P < 0.01 between the groups at 12 months and P < 0.001 at 24 months) in TH, respectively. The BMD increase in LS from 12 to 24 months was negatively associated with the levels of bone resorption marker at 24 months. Incidences of major fragility fractures for the respective groups were as follows: Naïve (5.5%), BP (16.2%), DMAb (11.1%), and TPTD (5.9%).

CONCLUSIONS

Previous treatment affected the BMD increase of following treatment with ROMO, although it did not affect that of following treatment with DMAb after ROMO.

Influence of concurrent and staggered dosing of semi-solid nutrients on the pharmacokinetics of orally administered carbamazepine in rats

In the present study, we examined the effects of concurrent and staggered dosing of PG-soft ace-MP TM (PG), novel semi-solid enteral nutrients, on the pharmacokinetics of orally administered carbamazepine (CBZ) in rats due to the high possibility of drug interaction during the absorption process. The pharmacokinetic behavior of CBZ was considerably altered when administered concurrently with PG. The maximum serum CBZ concentration (C_max) significantly decreased and the mean residence time (MRT) significantly increased. The elimination constant (k_e) also significantly increased, but there were no significant changes in the area under the serum CBZ concentration versus time curve (AUC) and the time to reach C_max (T_max). However, these changes in the pharmacokinetic parameters were eliminated by waiting 20 min, the time interval equivalent to the T_max described above, between CBZ administration and PG dosing. This study suggested that PG interferes with CBZ absorption from the digestive tract, although staggered administration of CBZ and PG prevented their interaction.

Plasma concentration profiles for hepatotoxic pyrrolizidine alkaloid senkirkine in humans extrapolated from rat data sets using a simplified physiologically based pharmacokinetic model

AIM

The main aim of the current study was to obtain forward dosimetry assessments of pyrrolizidine alkaloid senkirkine plasma and liver concentrations by setting up a human physiologically based pharmacokinetic (PBPK) model based on the limited information available.

BACKGROUND

The risks associated with plant-derived pyrrolizidine alkaloids as natural toxins have been assessed.

OBJECTIVE

The pyrrolizidine alkaloid senkirkine was investigated because it was analyzed in a European transcriptomics study of natural hepatotoxins and in a study of the alkaloidal constituents of traditional Japanese food plants Petasites japonicus. The in silico human plasma and liver concentrations of senkirkine were modeled using doses reported for acute-term toxicity in humans.

METHODS

Using a simplified PBPK model established using rat pharmacokinetic data, forward dosimetry was conducted. Since in vitro rat and human intrinsic hepatic clearances were similar; an allometric scaling approach was applied to rat parameters to create a human PBPK model.

RESULTS

After oral administration of 1.0 mg/kg in rats in vivo, water-soluble senkirkine was absorbed and cleared from plasma to two orders of magnitude below the maximum concentration in 8 h. Human in silico senkirkine plasma concentration curves were generated after virtual daily oral administrations of 3.0 mg/kg senkirkine (the dose involved in an acute fatal hepatotoxicity case). A high concentration of senkirkine in the culture medium caused in vitro hepatotoxicity as evidenced by lactate dehydrogenase leakage from human hepatocyte-like HepaRG cells.

CONCLUSION

Higher virtual concentrations of senkirkine in human liver and plasma than those in rat plasma were estimated using the current rat and human PBPK models. Current simulations suggest that if P. japonicus (a water-soluble pyrrolizidine alkaloid-producing plant) is ingested daily as food, hepatotoxic senkirkine could be continuously present in human plasma and liver.

Roles of human cytochrome P450 1A2 in coumarin 3,4-epoxidation mediated by untreated hepatocytes and by those metabolically inactivated with furafylline in previously transplanted chimeric mice

Coumarin is a naturally occurring component of food products but is of clinical interest for its potential hepatotoxicity in humans. In the current study, the pharmacokinetics of coumarin in humanized-liver mice after oral and intravenous administrations (30 mg/kg) were investigated for its transformations to metabolically active coumarin 3,4-epoxide (as estimated by the levels of o-hydroxyphenylacetic acid) and to excretable 7-hydroxycoumarin. After oral administration, control mice metabolized coumarin to o-hydroxyphenylacetic acid at roughly the same rate as that to 7-hydroxycoumarin (total of unconjugated and conjugated forms). In contrast, the in vivo biotransformation of coumarin to o-hydroxyphenylacetic acid by humanized-liver mice was around two orders of magnitude less than that to conjugated and unconjugated 7-hydroxycoumarin. After intravenous administrations of coumarin, differences were observed in the plasma concentrations of o-hydroxyphenylacetic acid between humanized-liver mice treated with furafylline (daily oral doses of 13 mg/kg for 3 days) and untreated humanized-liver mice. The mean values of the areas under the plasma concentration versus time curves and the maximum concentrations for o-hydroxyphenylacetic acid were significantly lower in the group treated with furafylline (45% and 57% of the untreated values, respectively). These results suggested that the metabolic activation of coumarin in humans was mediated mainly by P450 1A2, which was suppressed by furafylline, and that humanized-liver mice orally treated with furafylline might constitute an in vivo model for metabolically inactivated P450 1A2 in human hepatocytes transplanted into chimeric mice.

Machine Learning Prediction of the Three Main Input Parameters of a Simplified Physiologically Based Pharmacokinetic Model Subsequently Used to Generate Time-Dependent Plasma Concentration Data in Humans after Oral Doses of 212 Disparate Chemicals

Physiologically based pharmacokinetic (PBPK) modeling has the potential to play significant roles in estimating internal chemical exposures. The three major PBPK model input parameters (i.e., absorption rate constants, volumes of the systemic circulation, and hepatic intrinsic clearances) were generated in silico for 212 chemicals using machine learning algorithms. These input parameters were calculated based on sets of between 17 and 65 chemical properties that were generated by in silico prediction tools before being processed by machine learning algorithms. The resulting simplified PBPK models were used to estimate plasma concentrations after virtual oral administrations in humans. The estimated absorption rate constants, volumes of the systemic circulation, and hepatic intrinsic clearance values for the 212 test compounds determined traditionally (i.e., based on fitting to measured concentration profiles) and newly estimated had correlation coefficients of 0.65, 0.68, and 0.77 (p < 0.01, n = 212), respectively. When human plasma concentrations were modeled using traditionally determined input parameters and again using in silico estimated input parameters, the two sets of maximum plasma concentrations (r = 0.85, p < 0.01, n = 212) and areas under the curve (r = 0.80, p < 0.01, n = 212) were correlated. Virtual chemical exposure levels in liver and kidney were also estimated using these simplified PBPK models along with human plasma levels. These results indicate that the PBPK model input parameters for humans of a diverse set of compounds can be reliability estimated using chemical descriptors calculated using in silico tools.

Differences in Pharmacokinetics and Haematotoxicities of Aniline and Its Dimethyl Derivatives Orally Administered in Rats

Aniline and its dimethyl derivatives reportedly become haematotoxic after metabolic N-hydroxylation of their amino groups. The plasma concentrations of aniline and its dimethyl derivatives after single oral doses of 25 mg/kg in rats were quantitatively measured and semi-quantitatively estimated using LC-tandem mass spectrometry. The quantitatively determined elimination rates of aniline; 2,4-dimethylaniline; and 3,5-dimethylaniline based on rat plasma versus time curves were generally rapid compared with those of 2,3-; 2,5-; 2,6-; and N,2-dimethylaniline. The primary acetylated metabolites of aniline; 2,4-dimethylaniline; and 3,5-dimethylaniline, as semi-quantitatively estimated based on their peak areas in LC analyses, were more extensively formed than those of 2,3-; 2,5-; 2,6-; and N,2-dimethylaniline. The areas under the curve of unmetabolized (remaining) aniline and its dimethyl derivatives estimated using simplified physiologically based pharmacokinetic models (that were set up using the experimental plasma concentrations) showed an apparently positive correlation with the reported lowest-observed-effect levels for haematotoxicity of these chemicals. In the case of 2,4-dimethylaniline, a methyl group at another C4-positon would be one of the determinant factors for rapid metabolic elimination to form aminotoluic acid. These results suggest that rapid and extensive metabolic activation of aniline and its dimethyl derivatives occurred in rats and that the presence of a methyl group at the C2-positon may generally suppress fast metabolic rates of dimethyl aniline derivatives that promote metabolic activation reactions at NH2 moieties.

An Updated In Silico Prediction Method for Volumes of Systemic Circulation of 323 Disparate Chemicals for Use in Physiologically Based Pharmacokinetic Models to Estimate Plasma and Tissue Concentrations after Oral Doses in Rats

Updated algorithms for predicting the volumes of systemic circulation (V₁), along with absorption rate constants and hepatic intrinsic clearances, as input parameters for physiologically based pharmacokinetic (PBPK) models were established to improve the accuracy of estimated plasma and tissue concentrations of 323 chemicals after virtual oral administrations in rats. Using ridge regression with an enlarged set of chemical descriptors (up to 99), the estimated input V₁ values resulted in an improved correlation coefficient (from 246 compounds) with the traditionally determined values. The PBPK model input parameters for rats of diverse compounds can be precisely estimated by increasing the number of descriptors.

Barthel Index score predicts mortality in elderly heart failure: a goal of comprehensive cardiac rehabilitation

Background

Accurate prediction of mortality in heart failure (HF) patients is crucial for decision-making regarding HF therapies, but a strategy for the prediction of mortality in elderly HF patients has not been established. In addition, although favorable effects of comprehensive cardiac rehabilitation (CR) on clinical outcomes and functional status in HF patients have been demonstrated, a goal of comprehensive CR during hospitalization for reducing mortality remains unclear.

Aims

We examined whether assessment of basic activities of daily living (ADL) by the Barthel Index (BI), the most widely used tool for assessment of basic ADL, is useful for predicting all-cause mortality in elderly HF patients who received comprehensive CR.

Methods

This study was a single-center, retrospective and observational study. We retrospectively examined 413 HF patients aged ≥65 years (mean age, 78±7 years; 50% female) who were admitted to our institute for management of HF and received comprehensive CR during hospitalization. Functional status for performing basic ADL ability was assessed by the BI within 3 days before discharge. The clinical endpoint was all-cause death during the follow-up period.

Results

Of 413 HF patients, 116 patients (28%) died during a follow-up period of median 1.90-years (interquartile range, 1.20–3.23 years). Results of an adjusted dose-dependent association analysis showed that the hazard ratio (HR) of mortality increases in an almost linear fashion as the BI score decreases and that the BI score corresponding the hazard ratio of 1.0 is 85 (Figure A). To minimize the differences in potential confounding factors between patient with low BI (&lt;85) and patients with high BI (≥85), inverse probability treatment weighting (IPTW) was calculated using propensity score. Kaplan-Meier survival curves, in which selection bias was minimized by use of IPTW for confounders, showed that patients with low BI (&lt;85) had a higher mortality rate than did patients with high BI (≥85) (Figure B). In multivariate Cox regression analyses, low BI was independently associated with higher mortality after adjustment for predictors including brain natriuretic peptide and prior HF hospitalization (IPTW-adjusted HR, 1.75 [95% confidence interval, 1.03–2.98], p&lt;0.001). Inclusion of the BI into the adjustment model improved the accuracy of prediction of mortality (continuous net reclassification improvement, 0.292, p=0.008; integrated discrimination improvement, 0.017, p=0.022).

Conclusion

A BI score of &lt;85 at the time of discharge is associated with increased mortality independently of known prognostic markers, and achievement of functional status of a BI score ≥85 by comprehensive CR during hospitalization may contribute to a favorable outcome in elderly HF patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): the Japan Society for the Promotion of Science

Intracellular localization of AMP deaminase and its novel role in BCAA and lipid metabolism in diabetic cardiomyopathy

Background

A metabolomic study in the human heart suggested a pivotal role of amino acid (AA) metabolism in fatty acid oxidation, which is dysregulated in type 2 diabetes mellitus (T2DM) and heart failure. We previously reported that aberrant up-regulation of AMP deaminase 3 (AMPD3) impairs cardiac energetics in T2DM hearts, and AMPD3 was recently shown to be activated by fasting and to promote AA metabolism and fatty acid oxidation in skeletal muscle. A sodium glucose cotransporter 2 inhibitor (SGLT2i) has been shown to augment systemic AA metabolism, but its effect on cardiac AA metabolism remains unknown.

Purpose

We hypothesized that AMPD3 has a role in AA and lipid metabolism in cardiomyocytes and that the protective effect of an SGLT2i in diabetic hearts is mediated by modification of AA and lipid metabolism.

Methods and results

Proteomic analyses of AMPD3 immunoprecipitates in rat hearts revealed that AMPD3 interacted with the E1α and E2 components of the BCKDH complex, a rate-limiting enzyme of branched-chain AA (BCAA) catabolism. Immunoblotting using subcellular fractions revealed that BCKDH localized not only in the mitochondria matrix but also in the cytosol and endoplasmic reticulum (ER) and that AMPD3 interacted with BCKDH in the cytosol and ER. Despite comparable expression of BCKDH components and phosphorylation of E1α at Ser293, significant accumulation of BCAA was observed in T2DM rats (OLETF; 317±30 nmol/g) compared to that in control rats (LETO; 213±16 nmol/g), and the accumulation of BCAA was accompanied by up-regulation of AMPD3 in the cytosol and ER by 98% and 231%, respectively. In cardiomyocytes, disruption of BCAA catabolism by knockdown of BCKDH-E1α resulted in a 5.8-fold increase in AMPD3 at the transcriptional level and blunted lipid droplet biogenesis in response to a long-chain fatty acid challenge. Next, myocardial infarction (MI) was induced in LETO and OLETF pretreated with empagliflozin (10 mg/kg/day, 14 days) or a vehicle. Pathway analysis of cardiac metabolites revealed arginine biosynthesis and BCAA metabolism as the most significantly changed pathways with empagliflozin, with BCAA (791±187 nmol/g), glutamate, glutamine and urea being significantly increased. Empagliflozin restored myocardial ATP and survival after MI in OLETF to levels comparable to those in LETO. Electron microscopy showed a significantly higher prevalence of myocardium lipid droplets in OLETF, which was further increased by empagliflozin.

Conclusions

The results support the hypotheses that imbalance of extra-mitochondrial AMPD3-BCKDH interaction underlies dysregulated BCAA metabolism in T2DM hearts and that activation of cardiac AA metabolism by an SGLT2i normalizes fatty acid overload through sequestration into intracellular lipid droplets.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Boehringer Ingelheim

Is GLP-1 insufficiency a coronary risk factor? A multicenter observational study, BOREAS-CAD2

Background and aim

Glucagon-like peptide-1 (GLP-1) regulates insulin secretion and also affords pleiotropic effects including protective effects on blood vessels. Multiple factors regulate GLP-1 secretion after meals, but a group of apparently healthy subjects showed blunted responses of GLP-1 secretion in our previous study. In this study, we examined the possibility that the reduced capacity of GLP-1 secretion is associated with increased extent of coronary artery stenosis in non-diabetic patients.

Methods and results

Non-diabetic patients who were admitted for coronary angiography without a history of coronary interventions were enrolled. Coronary artery stenosis was quantified by Gensini score (GS), and GS ≥10 was used as an outcome variable based on results of earlier studies indicating its predictive value for cardiovascular events. The patients (mean age, 66.5±8.8 years; 71% males, n=173) underwent oral 75 g-glucose tolerant tests for determination of glucose, insulin and active GLP-1 levels. The area under the curve of plasma active GLP-1 (AUC-GLP-1) was determined as an index of GLP-1 secretion capacity. AUC-GLP-1 was not correlated with fasting glucose, AUC-glucose, serum lipids, indices of insulin sensitivity or estimated glomerular filtration rate. In multivariate logistic regression analysis for GS ≥10, AUC-GLP-1 &lt; median, age and hypertension were selected as explanatory variables, though fasting GLP-1 level was not selected.

Conclusion

The findings indicate significant association of reduced GLP-1 secretion capacity with increased extent of coronary artery stenosis in non-diabetic patients. A causal relationship between change in GLP-1 secretion capacity and coronary stenosis remains to be examined by a longitudinal study

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): This study was supported in part by a research grant from Investigator-Initiated Studies Program of Merck Sharp & Dohme Corp./MSD K.K.

Chlorine dioxide is a more potent antiviral agent against SARS-CoV-2 than sodium hypochlorite

BACKGROUND

A new coronavirus (SARS-CoV-2) abruptly emerged in Wuhan, China, in 2019 and rapidly spread globally to cause the COVID-19 pandemic.

AIM

To examine the anti-SARS-CoV-2 activity of the potent disinfectant Cleverin, the major disinfecting component of which is chlorine dioxide (ClO₂); and to compare the results with that of sodium hypochlorite in the presence or absence of 0.5% or 1.0% foetal bovine serum (FBS).

METHODS

Concentrated SARS-CoV-2 viruses were treated with various concentrations of ClO₂ and sodium hypochlorite and 50% tissue culture infective dose was calcurated to evaluate the antiviral activity of each chemical.

FINDINGS

When SARS-CoV-2 viruses were treated with 0.8 ppm ClO₂ or sodium hypochlorite, viral titre was decreased only by 1 log₁₀ TCID₅₀/mL in 3 min. However, the viral titre was decreased by more than 4 log₁₀ TCID₅₀/mL when treated with 80 ppm of each chemical for 10 s regardless of presence or absence of FBS. It should be emphasized that treatment with 24 ppm of ClO₂ inactivated more than 99.99% SARS-CoV-2 within 10 s or 99.99% SARS-CoV-2 in 1 min in the presence of 0.5% or 1.0% FBS, respectively. By contrast, 24 ppm of sodium hypochlorite inactivated only 99% or 90% SARS-CoV-2 in 3 min under similar conditions. Notably, except for ClO₂, the other components of Cleverin such as sodium chlorite, decaglycerol monolaurate, and silicone showed no significant antiviral activity.

CONCLUSION

Altogether, the results strongly suggest that although ClO₂ and sodium hypochlorite are strong antiviral agents in absence of organic matter but in presence of organic matter, ClO₂ is a more potent antiviral agent against SARS-CoV-2 than sodium hypochlorite.

Hepatotoxicological potential of P-toluic acid in humanised-liver mice investigated using simplified physiologically based pharmacokinetic models

p-Toluic acid, a metabolite of organic solvent xylene, has a high reported no-observed-effect level (NOEL, 1000 mg/kg) in rats, possibly because of direct glycine conjugation to methylhippuric acid. In this study, plasma levels of p-toluic acid and its glycine conjugate in mice and humanised-liver mice were evaluated after oral administrations.Although rapid conversion of p-toluic acid to its glycine conjugate was evident from mouse plasma concentrations, the biotransformation of p-toluic acid was slower in humanised-liver mice. The input parameters for physiologically based pharmacokinetic (PBPK) models were determined using fitting procedures to create PBPK-generated plasma concentration curves.The PBPK-modelled hepatic concentrations of p-toluic acid in humanised-liver mice were higher than those observed in plasma. PBPK-modelled hepatic and plasma concentrations of p-toluic acid also indicated slow elimination in humans.These results suggest that rapid conjugations of p-toluic acid reportedly observed in rats could result in overestimation of NOELs for conjugatable chemicals when extrapolated to humanised-liver mice or humans.

Expressions of conventional vitellogenin and vitellogenin-like A in worker brains are associated with a nursing task in a ponerine ant

In eusocial insect colonies, non-reproductive workers often perform different tasks. Tasks of an individual worker are shifted depending on various factors, e.g., age and colony demography. Although a vitellogenin (Vg) gene play regulatory roles in both reproductive and non-reproductive division of labours in a honeybee, it has been shown that the insect Vg underwent multiple gene duplications and sub-functionalisation, especially in apical ant lineages. The regulatory roles of duplicated Vgs were suggested to change evolutionarily among ants, whereas such roles in phylogenetically basal ants remain unclear. Here, we examined the expression patterns of conventional Vg (CVg), Vg-like A, Vg-like B and Vg-like C, as well as Vg receptor, during the task shift in an age-dependent manner and under experimental manipulation of colony demography in a primitive ant Diacamma sp. Expressions of CVg and Vg-like A in a brain were associated with a nursing task. It is suggested that associations of brain expressions of these Vgs with worker tasks were acquired in the basal ant lineage, and that such Vg functions could have sub-functionalised in the derived ant lineage.

In Silico Prediction of Input Parameters for Simplified Physiologically Based Pharmacokinetic Models for Estimating Plasma, Liver, and Kidney Exposures in Rats after Oral Doses of 246 Disparate Chemicals

Recently developed computational models can estimate plasma, hepatic, and renal concentrations of industrial chemicals in rats. Typically, the input parameter values (i.e., the absorption rate constant, volume of systemic circulation, and hepatic intrinsic clearance) for simplified physiologically based pharmacokinetic (PBPK) model systems are calculated to give the best fit to measured or reported in vivo blood substance concentration values in animals. The purpose of the present study was to estimate in silico these three input pharmacokinetic parameters using a machine learning algorithm applied to a broad range of chemical properties obtained from several cheminformatics software tools. These in silico estimated parameters were then incorporated into PBPK models for predicting internal exposures in rats. Following this approach, simplified PBPK models were set up for 246 drugs, food components, and industrial chemicals with a broad range of chemical structures. We had previously generated PBPK models for 158 of these substances, whereas 88 for which concentration series data were available in the literature were newly modeled. The values for the absorption rate constant, volume of systemic circulation, and hepatic intrinsic clearance could be generated in silico by equations containing between 14 and 26 physicochemical properties. After virtual oral dosing, the output concentration values of the 246 compounds in plasma, liver, and kidney from rat PBPK models using traditionally determined and in silico estimated input parameters were well correlated (r ≥ 0.83). In summary, by using PBPK models consisting of chemical receptor (gut), metabolizing (liver), excreting (kidney), and central (main) compartments with in silico-derived input parameters, the forward dosimetry of new chemicals could provide the plasma/tissue concentrations of drugs and chemicals after oral dosing, thereby facilitating estimates of hematotoxic, hepatotoxic, or nephrotoxic potential as a part of risk assessment.

Pharmacokinetics of primary oxidative metabolites of thalidomide in rats and in chimeric mice humanized with different human hepatocytes

The approved drug thalidomide is teratogenic in humans, nonhuman primates, and rabbits but not in rodents. The extensive biotransformation of 5'-hydroxythalidomide after oral administration of thalidomide (250 mg/kg) in rats was investigated in detail using liquid chromatography-tandem mass spectrometry. Probable metabolites 5'-hydroxythalidomide sulfate and glucuronide were extensively formed, with approximately tenfold and onefold peak areas, respectively, to the primary 5'-hydroxythalidomide measured using authentic standards. As a minor metabolite, 5-hydroxythalidomide was also detected. The output of simplified physiologically based pharmacokinetic rat models was consistent with the observed in vivo data under a metabolic ratio of 0.05 for the hepatic intrinsic clearance of thalidomide to unconjugated 5'-hydroxythalidomide. The aggregate of unconjugated and sulfate/glucuronide conjugated 5'-hydroxythalidomide forms appear to be the predominant metabolites in rats. Two hours after oral administration of thalidomide (100 mg/kg) to chimeric mice humanized with four different batches of genotyped human hepatocytes, the plasma concentration ratios of 5-hydroxythalidomide to 5'-hydroxythalidomide were correlated with replacement indexes of human liver cells previously transplanted in immunodeficient mice. These results indicate that rodent livers mediate thalidomide primary oxidation, leading to extensive deactivation in vivo to unconjugated/conjugated 5'-hydroxythalidomide and suggest that thalidomide activation might be dependent on the humanized livers in mice transplanted with human hepatocytes.

Metabolic profiles of coumarin in human plasma extrapolated from a rat data set with a simplified physiologically based pharmacokinetic model

Coumarin is a dietary-derived substance that is extensively metabolized by human liver to excretable 7-hydroxycoumarin. Although coumarin under daily dietary consumption is generally regarded as nontoxic, the substance is of toxicological and clinical interest because of its potential association with hepatotoxicity, which is especially evident in rats. In this study, the pharmacokinetics of coumarin were modeled after virtual oral administration in humans. The adjusted monitoring equivalents of coumarin, along with the biotransformation of coumarin to o-hydroxyphenylacetic acid (via 3,4-epoxidation) based on reported plasma concentrations from rat studies, were scaled to human coumarin equivalents using known species allometric scaling factors. Using rat and human liver preparations, data on the rapid in vitro metabolic clearance for humans (~50-fold faster than in rats) were obtained for in vitro-in vivo extrapolation. For human physiologically based pharmacokinetic (PBPK) modeling, the metabolic ratios to o-hydroxyphenylacetic acid and 7-hydroxycoumarin were set at minor (0.1) and major (0.9) levels for the total disappearance of coumarin. The resulting modeled plasma concentration curves in humans generated by simple PBPK models were consistent with reported simulated coumarin maximum concentrations. These results provide basic information to simulate plasma levels of coumarin and its primary metabolite 7-hydroxycoumarin or its secondary activated metabolite o-hydroxyphenylacetic acid (via 3,4-epoxidation) resulting from dietary foodstuff consumption. Under the current assumptions, little toxicological impact of coumarin was evident in humans, thereby indicating the usefulness of forward dosimetry using PBPK modeling for human risk assessment.

Plasma and hepatic concentrations of acetaminophen and its primary conjugates after oral administrations determined in experimental animals and humans and extrapolated by pharmacokinetic modeling

Plasma concentrations of acetaminophen, its glucuronide and sulfate conjugates, and cysteinyl acetaminophen were experimentally determined after oral administrations of 10 mg/kg in humanised-liver mice, control mice, rats, common marmosets, cynomolgus monkeys, and minipigs; the results were compared with reported human pharmacokinetic data. Among the animals tested, only rats predominantly converted acetaminophen to sulfate conjugates, rather than glucuronide conjugates. In contrast, the values of area under the plasma concentration curves of acetaminophen, its glucuronide and sulfate conjugates, and cysteinyl acetaminophen after oral administration of acetaminophen in marmosets and minipigs were consistent with those reported in humans under the present conditions. Physiologically based pharmacokinetic (PBPK) models (consisting of the gut, liver, and central compartments) for acetaminophen and its primary metabolite could reproduce and estimate, respectively, the plasma and hepatic concentrations of acetaminophen in experimental animals and humans after single virtual oral doses. The values of area under the curves of hepatic concentrations of acetaminophen estimated using PBPK models were correlated with the measured levels of cysteinyl acetaminophen (a deactivated metabolite) in plasma fractions in these species. Consequently, using simple PBPK models and plasma data to predict hepatic chemical concentrations after oral doses could be helpful as an indicator of in vivo possible hepatotoxicity of chemicals such as acetaminophen.

Metabolic Profiles of Tetrabromobisphenol A in Humans Extrapolated from Humanized-Liver Mouse Data Using a Simplified Physiologically Based Pharmacokinetic Model

Tetrabromobisphenol A, a brominated flame retardant, is increasingly prevalent worldwide and presents a potential health risk. Adjusted animal biomonitoring equivalents of tetrabromobisphenol A after orally administered doses in humanized-liver mice were scaled up to humans using known species allometric scaling factors to set up simplified physiologically based pharmacokinetic (PBPK) models. Absorbed tetrabromobisphenol A was slightly, moderately, and extensively metabolized in vivo to its glucuronide in rats, control mice, and humanized-liver mice tested, respectively. In silico estimated hepatic exposures of tetrabromobisphenol A and its glucuronide generated using the rat PBPK model-generated plasma concentration profiles were consistent with the reported values. The extent of hepatic injury in humanized-liver mice caused by tetrabromobisphenol A was evaluated by detecting human albumin mRNA in mouse plasma after oral administration of a high dose of tetrabromobisphenol A (1000 mg/kg). Reverse dosimetry analyses were carried out using two human PBPK models (set up based on the humanized-liver-mouse model and by optimizing the input parameters for reported human plasma concentrations of tetrabromobisphenol A glucuronide) to estimate the tetrabromobisphenol A daily intake based on reported human serum concentrations of total tetrabromobisphenol A from biomonitoring data. Within the predictability of the forward and reverse dosimetry estimations, the calculated daily intake was found to be far below established health benchmark levels (i.e., the suggested daily reported reference dose) with a wide (4 orders of magnitude) safety margin. These results suggest that the simplified PBPK models can be successfully applied to forward and reverse dosimetry estimations of tissue and/or blood exposures of tetrabromobisphenol A in humans after oral doses.

Clinical determinants and prognostic impact of osteoporosis in patients with chronic heart failure

Background

Despite accumulating evidence of a close association between orthopedic fractures and chronic heart failure (CHF), the clinical risk factors of osteoporosis, defined as reduction in bone mineral densities (BMDs), in CHF patients have not been systematically analyzed. In addition, the impact of osteoporosis on prognosis of CHF remains unclear.

Aims

We aimed to clarify the prevalence, clinical risk factors, and prognostic impact of osteoporosis in CHF patients.

Methods

We retrospectively examined 303 CHF patients (75 years, [interquartile range (IQR), 66–82 years]; 41% female). BMDs at the lumber spine, femoral neck, and total femur were measured by dual-energy X-ray absorptiometry (DEXA), and osteoporosis was diagnosed when BMD at any of the three sites was less than 70% of Young Adult Mean.

Results

The prevalence of osteoporosis in the CHF patients was 40%. Patients with osteoporosis were older (79 [IQR, 74–86] vs. 72 [IQR, 62–80] years), included a large percentage of females, had slower gait speed and had lower body mass index (BMI). Loop diuretics and warfarin were used more frequently and direct oral anticoagulants (DOACs) were used less frequently in patients with osteoporosis than in patients without osteoporosis. Multivariate logistic regression analysis indicated that sex (odds ratio [OR] 5.07, 95% Confidence Interval [CI] 2.68–9.61, p&lt;0.01), BMI (OR, 0.83; 95% CI, 0.75–0.91; p&lt;0.01), gait speed (OR, 0.80; 95% CI, 0.70–0.92; p&lt;0.01), loop diuretics use (OR, 2.52; 95% CI, 1.20–5.27; p=0.01) and no DOACs use (OR, 0.43; 95% CI, 0.19–0.96; p=0.04) were independently associated with osteoporosis. During the mean follow-up period of 290±254 days, 92 patients (30.4%) had adverse events. When patients with osteoporosis were divided into subgroups according to the number of sites with BMD of an osteoporosis level, Kaplan-Meier survival curves showed that the rate of adverse events (death and cardiovascular events) was higher in patients with osteoporotic BMD at two or more sites than in patients without osteoporosis (51% vs. 23%, p=0.03) (Figure). In multivariate Cox regression analyses, osteoporotic BMD at two or more sites was an independent predictor of adverse events after adjustment for age, sex, and NT-proBNP level (Hazard ratio, 1.74; 95% CI, 1.01–2.99; p=0.04).

Conclusion

The risk of osteoporosis may be increased in users of loop diuretics and may be decreased in users of DOACs in CHF patients. Extent of osteoporosis is a novel predictor of adverse events in CHF patients.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): The Japan Society for the Promotion of Science KAKENHI

Impact of frailty on super elderly patients with peripheral artery disease from the I-PAD 3 year registry

Background

Unlike age, frailty is often not taken into account in treatment indications of Endovascular treatment (EVT). One of the reason is that there was little known the relationship between frailty and the outcome of EVT for super elderly patients with peripheral artery disease (PAD). We investigate impacts of frailty on the super elderly patient prognosis who underwent EVT.

Purpose

To investigate impacts of frailty on the super elderly patient prognosis who underwent EVT.

Methods

From August 2015 to July 2016, 335 consecutive patients who underwent EVT were enrolled in the I-PAD registry from 7 institutes in Nagano prefecture. Among them, we selected and analyzed 91 super elderly PAD patients (≥80 years-old) and divided them into two groups:those with moderate or higher frailty (Clinical Frailty Scale (CFS) ≥6, n=28) and those without (CFS ≤5, n=63). The primary endpoints were cardiovascular death and major adverse cardiovascular and limb events (MACLE), defined as a composite of cardiovascular death, myocardial infarction, stroke, admission for heart failure, major amputation and revascularization.

Results

The median follow-up period was 2.7 years. Freedom rate from cardiovascular death and MACLE were significantly lower among patients with moderate or higher frailty than among those without (47.0% vs. 58.0%, P=0.03; 39.1% vs. 68.5%, P&lt;0.01).

Conclusion

The prognosis of super elderly patients with moderate or higher frailty is worse than those without.

Funding Acknowledgement

Type of funding source: None

Inhibition of xanthine oxidase ameliorates functional and metabolic impairment in type 2 diabetic hearts under pressure overload

Background

We recently reported that upregulated AMP deaminase (AMPD), via reduction in the tissue adenine nucleotide pool, contributes to exacerbation of diastolic dysfunction under pressure overload in OLETF, a rat model of obese type 2 diabetes (T2DM). Upregulated AMPD also possibly promotes xanthine oxidase (XO)-mediated ROS production, since AMPD deaminases AMP to IMP, which is further converted to inosine, providing substrates of XO, hypoxanthine and xanthine. Here, we examined the hypothesis that inhibition of XO ameliorates the pressure overload-induced diastolic dysfunction by suppression of ROS-mediated mitochondrial dysfunction and/or vascular dysfunction in T2DM rats.

Methods and results

Metabolomic analyses revealed that levels of xanthine and uric acid in the LV myocardium were significantly higher by 37% and 51%, respectively, in OLETF than in LETO, non-diabetic control rats, under the condition of phenylephrine-induced pressure overloading (200–230 mmHg). Myocardial XO activity in OLETF was 57.9% higher than that in LETO, which may be attributed to 31% higher level of inosine, a positive regulator of XO, in OLETF than in LETO. The activity of XO was significantly attenuated by administration of topiroxostat, an XO inhibitor at 0.5 mg/kg/day for 14 days. Pressure volume loop analyses showed that the pressure overloading resulted in significantly higher LVEDP in OLETF than in LETO (18.3±1.5 vs. 12.2±1.3 mmHg, p&lt;0.05, n=7), though LVEDPs at baseline were comparable in OLETF and LETO (5.6±0.4 vs. 4.7±0.7 mmHg). Treatment with topiroxostat significantly suppressed the pressure overload-induced elevation of LVEDP in OLETF (18.3±1.5 vs. 11.3±1.1 mmHg, p&lt;0.05) but not in LETO. Under the condition of pressure overloading, Ea/Ees, an index for ventricular-arterial coupling, was higher in OLETF than in LETO (2.3±0.3 vs. 1.6±0.3, p&lt;0.05), and it was also improved by topiroxostat in OLETF (1.2±0.2, p&lt;0.05). Myocardial ATP content was lower in OLETF than in LETO (2966±400 vs. 1818±171 nmol/g wet tissue, p&lt;0.05), and treatment with topiroxostat significantly restored the ATP level (2629±307 nmol/g wet tissue). The LV myocardium of OLETF under pressure overload showed significantly higher level of malondialdehyde and 4-hydroxynonenal, an indicator of lipid peroxidation, than that of LETO. Measurement of oxygen consumption rate by Seahorse XFe96 Analyzer in mitochondria isolated from LV tissues revealed that state 3 respiration was significantly suppressed in OLETF by 43% compared to LETO, and it was restored by treatment with topiroxostat.

Conclusion

Both activity and substrates of XO are increased in T2DM hearts, in which upregulation of AMPD may play a role. Inhibition of XO ameliorates pressure overload-induced diastolic dysfunction and improves ventricular-arterial coupling in diabetic hearts, most likely through protection of mitochondrial function from ROS-mediated injury.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant-in-aid for Scientific Research (#26461132, #17K09584) from the Japanese Society for the Promotion of Science

Reduced cytotoxicity in doxorubicin-exposed HepG2 cells pretreated with menthol due to upregulation of P-glycoprotein

The aim of the present study was to examine changes in the expression and activity of P-glycoprotein (P-gp) in human hepatocellular carcinoma HepG2 cells after exposure to menthol, and their relationship to the cytotoxicity of and apoptotic responses to doxorubicin (DOX), a substrate of P-gp, in the cells. The expression of P-gp in HepG2 cells was significantly increased by menthol treatment. Intracellular accumulation of DOX in HepG2 cells was significantly lower in the menthol-treated group than in the control group, but this phenomenon was abolished in the presence of verapamil. Decreased cell viability by DOX was significantly attenuated by 24-h menthol treatment prior to DOX exposure, which coincided with the changes in mRNA expression of Bcl-xl and caspase-3. These results demonstrate that menthol causes hepatocellular carcinoma cells to acquire resistance to DOX by increasing its efflux through the upregulation of P-gp.

Physiologically Based Pharmacokinetic Models Predicting Renal and Hepatic Concentrations of Industrial Chemicals after Virtual Oral Doses in Rats

Recently developed high-throughput in vitro assays in combination with computational models could provide alternatives to animal testing. The purpose of the present study was to model the plasma, hepatic, and renal pharmacokinetics of approximately 150 structurally varied types of drugs, food components, and industrial chemicals after virtual external oral dosing in rats and to determine the relationship between the simulated internal concentrations in tissue/plasma and their lowest-observed-effect levels. The model parameters were based on rat plasma data from the literature and empirically determined pharmacokinetics measured after oral administrations to rats carried out to evaluate hepatotoxic or nephrotic potentials. To ensure that the analyzed substances exhibited a broad diversity of chemical structures, their structure-based location in the chemical space underwent projection onto a two-dimensional plane, as reported previously, using generative topographic mapping. A high-throughput in silico one-compartment model and a physiologically based pharmacokinetic (PBPK) model consisting of chemical receptor (gut), metabolizing (liver), central (main), and excreting (kidney) compartments were developed in parallel. For 159 disparate chemicals, the maximum plasma concentrations and the areas under the concentration-time curves obtained by one-compartment models and modified simple PBPK models were closely correlated. However, there were differences between the PBPK modeled and empirically obtained hepatic/renal concentrations and plasma maximal concentrations/areas under the concentration-time curves of the 159 chemicals. For a few compounds, the lowest-observed-effect levels were available for hepatotoxicity and nephrotoxicity in the Hazard Evaluation Support System Integrated Platform in Japan. The areas under the renal or hepatic concentration-time curves estimated using PBPK modeling were inversely associated with these lowest-observed-effect levels. Using PBPK forward dosimetry could provide the plasma/tissue concentrations of drugs and chemicals after oral dosing, thereby facilitating estimates of nephrotoxic or hepatotoxic potential as a part of the risk assessment.

P207 Synergetic effect of amino acid and ketone metabolism underlies empagliflozin-mediated cardioprotection in the type 2 diabetic heart

Funding Acknowledgements

Boehringer Ingelheim

Background

 Although emerging evidence has indicated that sodium glucose cotransporter 2 (SGLT2) inhibitors restore impaired cardiac energetics in type 2 diabetes mellitus (T2DM), the underlying molecular mechanisms have yet to be established.  Augmented utilization of ketone is one proposed hypothesis, but depletion of succinyl-CoA triggered by the conversion of ketone back to acetyl-CoA by SCOT (succinyl-CoA:3-oxoacid CoA transferase) may hamper oxidative capacity of the tricarboxylic acid (TCA) cycle, which also requires succinyl-CoA.  The recent finding that empagliflozin augments systemic amino acid metabolism in patients with T2DM led us to hypothesize that the anaplerotic effect of amino acid on the TCA cycle complements ketone oxidation.

Methods and Results

 Myocardial infarction (MI) was induced in T2DM rats (OLETF) and control rats (LETO).  Survival rate at 48 hours after MI was significantly lower in OLETF than in LETO (40% vs 84%), and empagliflozin treatment (10 mg/kg/day, 14 days) before MI improved the survival rate in OLETF to 70%.  Metabolome analysis was performed using heart tissues from the non-infarct region 12 hours after MI.  Using principal component analysis, data from 92 metabolites that were detected were compressed into 2 dimensions, and the first component (PC1) clearly separated empagliflozin-treated OLETF from non-treated LETO and OLETF.  Analysis of factor loading of each metabolite for PC1 revealed that branched chain amino acids leucine, isoleucine and valine, the latter two of which can be oxidized to succynyl-CoA, and β-hydroxybutyrate were the top four metabolites that characterized empagliflozin treatment.  Furthermore, in comparison to LETO, OLETF treated with empagliflozin showed 50% higher levels of glutamine and glutamate, both of which can replenish the TCA cycle at the level of α-ketoglutarate.  In OLETF, empagliflozin significantly increased the TCA cycle intermediates citrate, cis-aconitate and malate by 74%, 119% and 59%, respectively.  OLETF showed 86% higher lactate and 38% lower ATP than those in LETO, but levels of the metabolites were normalized by empagliflozin, suggesting improved glucose oxidation.

Conclusions

  The present analyses showed that amino acid and ketone metabolism are metabolic pathways that are most affected by empagliflozin.  Coordination of these "starvation-induced pathways" may underlie the favorable metabolic effect of empagliflozin in T2DM hearts.

41 Geometric change in valvular apparatus during tricuspid repair for severe tricuspid regurgitation

Background

For repairing severe tricuspid regurgitation (TR) with leaflet tethering, our team employs spiral suspension procedure, in which papillary muscles (PMs) are approximated and suspended towards annulus by suture in addition to annuloplasty.

Purpose

To visualize subtricuspid apparatus and investigate its geometric change by the procedure, comparing with annuloplasty alone.

Methods

11 patients who underwent spiral suspension and 10 patients who underwent annuloplasty alone were studied. Using 3D dataset derived from transesophgeal echocardiography with transgastric approach, the distances between the mid septal annulus (point C) and the anterior PM tip (point A) and posterior PM (point P) were calculated. Also, annular perimeter, leaflet surface area and tenting height were measured

Results

In all cases, PM tips could be visualized and identified for the measurements. By spiral suspension, the distance CA and tenting height were significantly reduced. On the other hand, by annuloplasty alone, CA and tenting height were likely to be increased but statistically not significant.

Conclusions

Spiral suspension ameliorated leaflet tethering with relocating PMs. Annuloplasty alone reduced leaflet surface area, which indicates increase of coaptation surface. Interestingly, PM tip- annulus distance and tenting height were possibly increased by annuloplasty. Further investigation is need in large number.

Result of measurements Annuloplasty alone Spiral suspension Pre-op Post-op Pre-op Post-op Annular perimeter, mm 120.9 ± 11.2 78.8 ± 5.1* 142.4 ± 18.2* 81.1 ± 6.4** Leaflet surface area, cm2 13.1 ± 3.1 5.6 ± 0.9* 19.3 ± 4.8* 5.8 ± 0.8** Tenting height, mm 2.8 ± 2.3 3.1 ± 1.2 7.0 ± 4.8* 2.9 ± 2.6** CA, mm 27.3 ± 3.9 29.1 ± 6.2 35.7 ± 6.9* 29.6 ± 5.2** CP, mm 33.1 ± 6.0 33.8 ± 9.4 38.5 ± 8.2 33.9 ± 6.1 *p &lt; 0.05, vs Annuloplasty alone pre-op **p &lt; 0.05, vs Spiral suspension pre-op

Abstract 41 Figure. Pre- and post-operative valve apparatus

P121 Pressure overload-induced functional and metabolic impairments in type 2 diabetic hearts are ameliorated by inhibition of xanthine oxidase

Funding Acknowledgements

SANWA KAGAKU KENKYUSHO Co., Ltd.

Background

  We have recently demonstrated that AMP deaminase (AMPD) is upregulated in OLETF, obese type 2 diabetic (T2DM) rats, and that the upregulated AMPD contributes to depletion of myocardial ATP at the time of pressure overload, leading to diastolic dysfunction.  On the other hand, AMPD promotes the formation of IMP from AMP, and IMP is in turn further converted to hypoxanthine and xanthine, substrates of xanthine oxidase (XO), which produces uric acid with ROS as a byproduct.  Based on these findings, we tested the hypothesis that inhibition of XO ameliorates the pressure overload-induced diastolic dysfunction in T2DM rats. 

Methods and results

Metabolomic analyses of the left ventricular myocardium revealed that levels of myocardial hypoxanthine and xanthine were significantly higher by 30% and 28%, respectively, in OLETF than in LETO, non-diabetic control rats, under the condition of pressure overloading (200-230 mmHg) induced by phenylephrine infusion. Myocardial XO activity in OLETF was 57.9% higher than that in LETO, and the activity was significantly attenuated by oral administration of topiroxostat, an XO inhibitor, at 0.1-0.5 mg/kg/day for 14 days in a dose-dependent manner.  Pressure volume loop analyses showed that the pressure overloading induced by phenylephrine infusion resulted in significantly higher LVEDP in OLETF than in LETO (18.3 ± 1.5 vs. 12.2 ± 1.3 mmHg, p &lt; 0.05, n = 7), though LVEDPs at baseline were comparable in OLETF and LETO (5.6 ± 0.4 vs. 4.7 ± 0.7 mmHg).  Treatment with topiroxostat significantly suppressed the pressure overload-induced elevation of LVEDP in OLETF (18.3 ± 1.5 vs. 11.3 ± 1.1 mmHg, p &lt; 0.05) but not in LETO.  Tau, the time constant of LV pressure decay, was significantly prolonged to 14.7 ± 0.7 ms (p &lt; 0.05) by pressure overloading in OLETF but not in LETO, though baseline Tau values were similar in LETO and OLETF (6.1 ± 0.2 vs. 8.0 ± 0.4 ms).  The prolongation of Tau by pressure overloading in OLETF was significantly attenuated by treatment with topiroxostat.  Ea/Ees, an index for ventricular-arterial coupling, was higher in OLETF than in LETO (2.3 ± 0.3 vs. 1.6 ± 0.3, p &lt; 0.05) under the condition of pressure overloading, and it was also improved by topiroxostat in OLETF (1.2 ± 0.2, p &lt; 0.05).  Myocardial ATP content was lower in OLETF than in LETO under the condition of pressure overloading (2966 ± 400 vs. 1818 ± 171 nmol/g wet tissue, p &lt; 0.05), but treatment with topiroxostat significantly restored the ATP level (2629 ± 307 nmo/g wet tissue). Conclusion:  In T2DM hearts, not only XO activity but also XO substrates are upregulated and upregulated AMPD may be involved in the upregulation.  Inhibition of XO ameliorates pressure overload-induced diastolic dysfunction and improves ventricular-arterial coupling most likely through augmented ATP preservation.

CAPABILITIES OF THE ARADOS-WG03 REGIONAL NETWORK FOR LARGE-SCALE RADIOLOGICAL AND NUCLEAR EMERGENCY SITUATIONS IN ASIA

In 2015, the Asian Radiation Dosimetry Group established a regional network of biological dosimetry laboratories known as the ARADOS-WG03 (Working Group 03; Biological Dosimetry). A survey was conducted in 2017 to evaluate the capabilities and capacities of the participating laboratories for emergency preparedness and responses in large-scale nuclear and/or radiological incidents. The results of this survey were identified and assessed. The data provide important information on the current state of emergency cytogenetic biological dosimetry capabilities in the Asian region.

Different Roles of Human Cytochrome P450 2C9 and 3A Enzymes in Diclofenac 4'- and 5-Hydroxylations Mediated by Metabolically Inactivated Human Hepatocytes in Previously Transplanted Chimeric Mice

To investigate the respective roles of cytochromes P450 2C9 and 3A in drug oxidation in human livers, the in vivo pharmacokinetics of S-warfarin and diclofenac were analyzed after intravenous administrations in chimeric mice that had been transplanted with human hepatocytes. P450 2C9 was metabolically inactivated in the humanized mice by orally pretreating them with tienilic acid. After intravenous administration of S-warfarin, a significant difference in the concentration-time profiles of the primary metabolite 7-hydroxywarfarin between untreated mice and mice treated with tienilic acid was observed. In contrast, there were no apparent differences in the profiles for S-warfarin between the treated and untreated groups. The mean values of the maximum concentrations (C_max) and the areas under the plasma concentration versus time curves (AUC_infinity) for 7-hydroxywarfarin were significantly lower (22 and 16% of the untreated values, respectively) in the treated group. This presumably resulted from suppressed P450 2C9 activity in the primary oxidative metabolism in vivo in the treated group. After diclofenac administration, plasma levels of diclofenac, 5-hydroxydiclofenac, and diclofenac acylglucuronide were roughly similar in pretreated and untreated mice. However, the mean C_max and AUC_infinity values for 4'-hydroxydiclofenac were significantly lower (38 and 53% of the untreated group, respectively) in the treated group. The reported value of ∼0.8 for the fraction of S-warfarin metabolized to 7-hydroxywarfarin mediated by P450 2C9 in in vitro systems was similar to the value implied by the present humanized-liver mouse model pretreated with tienilic acid in which the AUC of 7-hydroxywarfarin was reduced by 84%. In contrast, the fractions of diclofenac metabolized to 4'-hydroxydiclofenac in in vitro and in vivo experiments were inconsistent. These results suggested that humanized-liver mice orally treated with tienilic acid might constitute an in vivo model for metabolically inactivated P450 2C9 in human hepatocytes transplanted into chimeric mice. Moreover, diclofenac, a typical in vitro P450 2C9 probe substrate, was cleared differently in vitro and in humanized-liver mice in vivo.

P943The impact of diabetes on patients with frail after endovascular treatments: from I-PAD registry

Background

Diabetes mellitus (DM) is known to be one of the risks of arteriosclerosis. However, it is still unknown whether DM is a risk factor also in secondary prevention of frail patients after endovascular treatments (EVT)

Purpose

To investigate impact of diabetes on patients with frail after EVT.

Methods

From July 2015 to July 2016, 371 consecutive PAD patients who performed EVT were enrolled in I-PAD registry. We could conduct follow up survey 361 patients (446 lesions) and divided into 2 groups; with diabetes (185 patients, 226 lesions) or without diabetes (176 patients, 220 lesions) and analyzed. And among them,we selected 96 patients with frail and divided into 2 groups; with diabetes (49 patients, 70 lesions) or without diabetes (46 patients, 58 lesions) and analyzed. We defined frail patients as the patients with Clinical Frailty Scale 5 (mild frail) or higher. The primary end point was all-cause-death and major adverse limb events (MALE: TLR, TVR, major amputations) at 1 year.

Result

At 1 years in the patients group with diabetes, overall survival and freedom from MALE were significantly lower (81.7% vs 95.8% P<0.0001; 80.0% vs 94.6%, P<0.0001) than the group without diabetes.Among the patients with frail, between the patients group with diabetes and the group without, there is no significant differences in overall survival and freedom from MALE (88.2% vs 88.9% P=0.83; 80.7% vs 84.1%, P=0.55) at 5 years.

Conclusion

The prognosis of patients with diabetes after EVT was worse than the patient without. On the other hand, the prognosis of frail patients with diabetes after EVT was no difference with the frail patient without diabetes in this study.

P942Impact of left ventricular ejection fraction in patients with critical limb ischemia: from I-PAD registry

Introduction

In patients with critical limb ischemia (CLI) it is known that malnutrition, low BMI, inflammation and so on are prognostic factors. But, it is unclear whether left ventricular ejection fraction (LVEF) affects prognosis of CLI patients. So we investigated that LVEF affects prognosis of CLI patients.

Methods

From July 2015 to July 2016, 371 consecutive peripheral artery disease patients who performed endovascular treatment (EVT) were enrolled in I-PAD registry. 179 of them were patients with CLI. We could conduct follow up survey about 126 (age 75.5±11.1, men 63.5%) and divided two groups according to their LVEF (group with LVEF≤40%, n=13, group without LVEF≤40%, n=113). The primary end point was major adverse limb events (MALE: TLR, TVR, major amputations) and secondary end point was all-cause death.

Results

The median follow-up period was 11.5±6.7 months. The 18 months MALE rate was significant higher in the group with low LVEF than group without low LVEF (76.9% vs 37.2% p<0.05). The 18months all-cause death tended to be higher in the group with low LVEF, however there was not statistical significance in the two groups (53.8% vs 24.8% p=0.09).

Conclusion

LVEF was associated with MALE in patients with CLI.

P6402Ischemic and bleeding events during dual antiplatelet therapy after second-generation drug-eluting stent implantation in hemodialysis patients: a propensity score-matched analysis

Background

Dual-antiplatelet therapy (DAPT) after second-generation drug eluting stent (2-DES) implantation reduced the risk of stent thrombosis and subsequent ischemic events, with an increase in bleeding risk. Although chronic kidney disease patients have high ischemic and bleeding risk, little is known about both risks in hemodialysis patients after 2-DES implantation during DAPT.

Method

From July 2009 to March 2017, we retrospectively analyzed post-discharge major adverse cardiac and cerebrovascular events [MACCE: cardiac death, myocardial infarction, target vessel revascularization (TVR) and cerebral infarction] and bleeding events in 644 consecutive patients during DAPT after 2-DES implantation. We divided them into 2 groups [102 hemodialysis (HD) and 518 non-hemodialysis (Non-HD) patients, mean age, 71±10 years] after excluding 24 patients (lost to follow up and peritoneal dialysis). Follow-up period was 49±24 months. Median DAPT duration was 12 months. The primary endpoint was MACCE. The secondary endpoint was bleeding events according to the Bleeding Academic Research Consortium (BARC) type 2, 3, or 5. MACCE and bleeding events were compared between HD and Non-HD by using the propensity score-matching (PSM) method.

Results

Among the 620 eligible patients, the primary and secondary events occurred in 207 (33.3%) and 76 (12.3%) patients, respectively. The rates of unadjusted MACCE [HD vs Non-HD: 53.9% vs 29.3%; Hazard ratio (HR) 2.39, p<0.01] and bleeding events (HD vs Non-HD: 21.6% vs 10.4%; HR 2.50, p<0.01) were significantly higher in HD than Non-HD.

After 1-to-1 propensity score adjustment for baseline differences (hypertension, diabetes mellitus, low ejection fraction, low albumin, anemia, and high C-reactive protein), a total of 160 patients (80 HD vs 80 Non-HD) was created. The rate of MACCE [HD vs Non-HD: 52.5% vs 31.3%; adjusted HR 2.04, p<0.01] was significantly higher in HD than Non-HD. Regarding MACCE, cardiac death (HD vs Non-HD: 18.8% vs 8.8%; adjusted HR 2.65, p=0.03) and TVR (HD vs Non-HD: 15.0% vs 6.3%; adjusted HR 2.74, p=0.046) occurred significantly higher in HD. On the other hand, bleeding events did not exhibit significant differences though HD had a numerically higher event rate (HD vs Non-HD: 25.0% vs 16.3%; adjusted HR 1.68, p=0.15), indicating that the bleeding risk in HD would be strongly dependent on the patient's background.

Conclusions

As a result of PSM, HD was shown to contribute to ischemic risk rather than bleeding risk. Even in the 2-DES era, HD was an independent risk factor of cardiac death and TVR. Therefore, further study on the current regimen of DAPT would be necessary while balancing both ischemic and bleeding risk.