Influence of genetic polymorphisms in vascular endothelial-related genes on the clinical outcome of axitinib in patients with metastatic renal cell carcinoma

OBJECTIVE

Axitinib is an oral multi-target tyrosine kinase inhibitor used for the treatment of renal cell carcinoma (RCC). Because of the severe adverse events (AEs) associated with axitinib, patients often need dose reductions or discontinue its use, highlighting the need for effective biomarkers to assess efficacy and/or AEs. The aim of this study was to investigate the relationship between single nucleotide polymorphisms (SNPs) in genes involved in the pharmacodynamic action of axitinib and clinical prognosis and AEs in metastatic RCC (mRCC) patients.

METHODS

This study included 80 mRCC patients treated with first-, second-, or third-line axitinib (5 mg orally twice daily). Clinical parameters and genetic polymorphisms were examined in 75 cases (53 males and 22 females). We assessed three SNPs in each of three candidate genes namely, angiotensin-converting enzyme (ACE), nitric oxide synthase 3 (NOS3), and angiotensin II receptor type 1 (AT1R), all of which are involved in axitinib effects on vascular endothelial function.

RESULTS

Axitinib-treated patients carrying the ACE deletion allele suffered more frequently from hand-foot syndrome and a deterioration in kidney function (p  = .045 and p =  0.005, respectively) whereas those carrying the NOS3 G allele suffered more frequently from proteinuria and multiple AEs (p  = .025 and p =  0.036, respectively).

CONCLUSIONS

Our study found that the ACE deletion allele and the NOS3 G allele are associated with increased AEs.

Overexposure to venetoclax is associated with prolonged-duration of neutropenia during venetoclax and azacitidine therapy in Japanese patients with acute myeloid leukemia

PURPOSE

An observational study was conducted to evaluate the pharmacokinetics of venetoclax and its impact on the efficacy and safety for Japanese patients with acute myeloid leukemia (AML) treated with venetoclax and azacitidine therapy.

METHODS

The association between the plasma concentration, after the first cycle of azacitidine and venetoclax therapy, and the efficacy and safety was evaluated in 33 patients with untreated or relapsed/refractory AML.

RESULTS

Full dose of venetoclax was administered to all patients. Venetoclax treatment was 28 day long in 82% of patients; the relative dose intensity of azacitidine was 82%. Trough concentration was significantly higher among patients with complete remission (CR) and CR with incomplete hematologic recovery (CRi) than those with the morphologic leukemia-free state and partial remission, and no response groups (P = 0.01). Median duration of grade 3 neutropenia was 28 days (range 8-46 days). Area under the concentration-time curve (AUC0-24) was significantly higher among patients with protracted grade 3 neutropenia (≥ 28 days) than those with a shorter duration (< 28 days) (P = 0.03); multivariate analysis revealed that a higher AUC0-24 was a significant predictor of a longer duration of neutropenia (odds ratio 54.3, P = 0.007).

CONCLUSION

Plasma concentrations of venetoclax were variable in Japanese patients with AML. Higher plasma concentrations were associated with CR/CRi and protracted grade 3 neutropenia. Therefore, it is essential to adjust the duration of venetoclax administration based on individual pharmacokinetic data to limit total drug exposure, reduce severe neutropenia, and achieve higher efficacy.

Association between albumin-bilirubin grade and plasma trough concentrations of regorafenib and its metabolites M-2 and M-5 at steady-state in Japanese patients

The aim of the present study was to determine whether the trough plasma concentrations (C0) of regorafenib and its metabolites, the N-oxide metabolite (M-2) and the desmethyl N-oxide metabolite (M-5), in 21 patients receiving regorafenib therapy were affected by albumin-bilirubin (ALBI) grade. Regorafenib was administered at dosages ranging from 40 to 160 mg once daily on a 3-week-on, 1-week-off cycle. C0 values of regorafenib and its major metabolites were measured by high-performance liquid chromatography on day 8 after treatment initiation. The C0 values of regorafenib and metabolites M-2 and M-5 were significantly lower in patients with ALBI grade 2 as compared with grade 1 (P = 0.023, 0.003 and 0.017, respectively). The total C0 of regorafenib and its metabolites was significantly higher in ALBI grade 1 patients relative to grade 2 (3.489 μg/mL vs. 1.48 μg/mL; P = 0.009). The median relative dose intensity (RDI) of patients categorized as ALBI grade 2 was significantly lower than that of grade 1 patients (21.9% vs. 62.9%; P = 0.006). In 15 colorectal cancer patients among the total 21 patients, patients with ALBI grade 2 (n = 9) had a significantly shorter median overall survival time than patients with grade 1 (n = 6; P = 0.013). Administering a low dose of regorafenib to patients with ALBI grade 2 reduces the RDI of regorafenib and lowers treatment efficacy, as an appropriate C0 of regorafenib is not maintained. Monitoring the C0 of regorafenib regularly is necessary to guide dose adjustment.

Mortality risk factors and fulminant sub-phenotype in anaerobic bacteremia: a 10-year retrospective, multicenter, observational cohort study

PURPOSE

During the last decade, the incidence of anaerobic bacteremia (AB) has been increasing. Patients with AB may develop complex underlying diseases, which can occasionally be accompanied by fatal or fulminant outcomes. However, the risk factors for AB-related mortality remain unclear. Herein, we sought to elucidate the risk factors for AB-related mortality.

METHODS

In this multicenter, retrospective, observational study, we enrolled patients with culture-proven AB from six tertiary hospitals in Japan, between January 2012 and December 2021. Data on patient and infection characteristics, laboratory findings, treatment, and outcome were collected, and their associations with mortality were analyzed.

RESULTS

A total of 520 participants were included. The 30-day mortality in the study cohort was 14.0% (73 patients), and malignant tumors were frequently observed comorbidities in 48% of the entire cohort. Multivariable logistic regression analysis showed a Charlson comorbidity score of > 6, serum creatinine level of > 1.17 mg/dL, and hypotension to be independent risk factors for 30-day mortality in AB (odds ratios [ORs] 2.12, 2.25, and 5.12, respectively; p < 0.05), whereas drainage significantly reduced this risk (OR, 0.28; p < 0.0001). Twelve patients (2.3% of the whole cohort and 16.4% of the deceased patients) presented with extremely rapid progression leading to fatal outcome, consistent with "fulminant AB."

CONCLUSIONS

This study identified acute circulatory dysfunction and performance of drainage as independent predictive factors for 30-day AB-related mortality and revealed the existence of a fulminant AB sub-phenotype. Our findings could serve as a practical guide to predict the clinical outcomes of AB.

Circulating IL-6 and not its circulating signaling components sIL-6R and sgp130 demonstrate clinical significance in NSCLC patients treated with immune checkpoint inhibitors

Introduction: Clinical roles of plasma IL-6 levels have been reported in patients with various cancers, including non-small cell lung cancer (NSCLC), treated with immune checkpoint inhibitors (ICIs). However, the roles of other IL-6 signaling components, soluble IL-6 receptor (sIL-6R) and soluble gp130 (sgp130), in the plasma have not been elucidated. Methods: Blood was collected from 106 patients with NSCLC before initiation of ICI treatment (anti-PD-1 or anti-PD-L1 antibody). Plasma levels of IL-6, sIL-6R, sgp130, and their complexes were assessed by Cox regression hazard model to evaluate their clinical significance. The clinical role of IL-6 or IL-6R genetic polymorphisms was also analyzed. Results: Cox regression analysis showed that higher plasma IL-6 levels significantly predicted unfavorable overall survival (OS; hazard ratio [HR] 1.34, 95% confidence interval [CI] 1.05-1.68, p = 0.012) in NSCLC patients treated with ICIs. However, plasma sIL-6R and sgp130 levels showed no prognostic significance (p = 0.882 and p = 0.934, respectively). In addition, the estimated concentrations of binary IL-6:sIL-6R and ternary IL-6:sIL-6R:sgp130 complexes and their ratios (binary/ternary complex) were not significantly associated with OS (p = 0.647, p = 0.727, and p = 0.273, respectively). Furthermore, the genetic polymorphisms of IL-6 (-634G>C) and IL-6R (48892A>C) showed no clinical role by Kaplan-Meier survival analysis (p = 0.908 and p = 0.639, respectively). Discussion: These findings demonstrated the clinical significance of plasma levels of IL-6, but not of other IL-6 signaling components, sIL-6R and sgp130, suggesting that classical IL-6 signaling, but not trans-signaling, may be related to anti-tumor immune responses in cancer patients treated with ICIs.

Quantitation of Venetoclax in Human Plasma by High-Performance Liquid Chromatography with Ultraviolet Detection

A simple, highly sensitive and specific method based on high-performance liquid chromatography (HPLC) with ultraviolet detection was developed for the measurement of venetoclax concentrations in plasma samples. The chromatographic method employed a mobile phase of acetonitrile: 0.5% KH2PO4 (pH 3.5) (80/20, v/v) on a CAPCELL PAK C18 UG120 column at a flow rate of 0.5 mL/min. The quantitative method was validated based on standards described in "Bioanalytical Method Validation: Guidance for Industry" published by the US Food and Drug Administration. The separation of venetoclax and the internal standard R051012 was satisfactory, and the chromatograms were free of interfering peaks from the biological matrix. The intra- and inter-day coefficients of variation for venetoclax assays were <12.9%, whereas intra- and inter-day accuracies were within 13.6%. Only 100 μL of human plasma was required to detect a lower limit of quantification of 10 ng/mL for venetoclax. The recoveries of venetoclax extracted with an Oasis HLB cartridge were between 81 and 85%. The developed HPLC method was successfully applied to the determination of venetoclax concentrations in plasma of acute myeloid leukemia patients taking venetoclax. The degree of drug interactions between venetoclax and CYP3A4 inhibitors can be determined by this HPLC assay.

Postruminal choline supply during negative nutrient balance alters components of hepatic mTOR signaling and plasma amino acids in lactating Holstein cows

Choline requirements for dairy cattle are unknown. However, enhanced postruminal supply of choline may increase flux through the methionine cycle to spare Met for other functions such as protein synthesis and phosphatidylcholine (PC) synthesis during periods of negative nutrient balance (NNB). The objective was to investigate the effects of postruminal choline supply during a feed restriction-induced NNB on hepatic abundance and phosphorylation of mTOR (mechanistic target of rapamycin)-related signaling proteins, hepatic lipidome and plasma AA. Ten primiparous rumen-cannulated Holstein cows (158 ± 24 DIM) were used in a replicated 5 × 5 Latin square design with 4 d of treatment and 10 d of recovery (14 d/period). Treatments were unrestricted intake with abomasal infusion of water, restricted intake (R; 60% of net energy for lactation requirements to induce NNB) with abomasal infusion of water (R0) or restriction plus abomasal infusion of 6.25, 12.5, or 25 g/d choline ion. Liver tissue was collected via biopsy on d 5 after infusions ended and used for Western blot analysis to measure proteins involved in mTOR signaling and untargeted lipidomics. Blood was collected on d 1 to 5 for plasma AA analysis. Statistical contrasts for protein and AA data were A0 versus R0 (CONT1), R0 versus the average of choline dose (CONT2) and tests of linear and quadratic effects of choline dose. Analysis of lipidomic data were performed with the web-based metabolomic processing tool MetaboAnalyst 5.0. Ratios of p-RPS6KB1:tRPS6KB1, p-EEF2:tEEF2, and p-EIF2:tEIF2 were greater with R (CONT1). Among those, supply of choline led to decreases in p-EEF2:tEEF2 (CONT2), p-EIF2:tEIF2 and tended to decrease p-EIF4BP1:tEIF4BP1. However, the effect was quadratic only for p-EEF2:tEEF2 and p-EIF2A:tEIF2A, reaching a nadir at 6.25 to 12.5 g/d choline ion. The ratio of p-RPS6KB1:tRPS6KB1 was not affected by supply of choline and was close to 2-fold greater at 25 g/d choline versus A0. Plasma Met concentration decreased with R (CONT1), but increased linearly with choline. Restriction also increased plasma 3-methyl-histidine (CONT1). The partial least squares discriminant analysis model of liver lipids distinguished treatments, with 13.4% of lipids being modified by treatment. One-way ANOVA identified 109 lipids with a false discovery rate ≤0.05. The largest group identified was PC species; all 35 detected decreased with R versus A0, but there were few differences among choline treatments. Overall, data suggested that dephosphorylation of EEF2 and EIF2A due to enhanced choline supply potentially helped maintain or increase protein synthesis during NNB. While activation of mTOR was not altered by choline, this idea of increased protein synthesis is partly supported by the increased circulating Met. However, enhanced postruminal choline had limited effects on the species of lipid produced during a period of NNB.

Erratum: Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande [Phys. Rev. Lett. 130, 031802 (2023)]

This corrects the article DOI: 10.1103/PhysRevLett.130.031802.

Effects of polymorphisms in pregnane X receptor and ABC transporters on afatinib in Japanese patients with non-small cell lung cancer: pharmacogenomic-pharmacokinetic and exposure-response analysis

PURPOSE

Because of the large interindividual variability of afatinib pharmacokinetics and adverse events, we evaluated the effects of polymorphisms in pregnane X receptor (NR1I2) and ABC transporters (ABCB1, ABCG2, and ABCC2) on the pharmacokinetics of afatinib.

METHODS

The steady-state area under the concentration-time curve (AUC)0-24 of afatinib was analyzed using blood sampling just prior to and at 1, 2, 4, 6, 8, 12, and 24 h on day 15 after administration.

RESULTS

The median oral clearance (CL/F) of afatinib in patients with the NR1I2 7635A allele was significantly lower than those in patients with the 7635G/G genotype (42.0 and 60.0 L/h, respectively, P = 0.025). There were no significant differences in afatinib CL/F between genotypes for NR1I2 8055C > T, -25385C > T, ABCB1, ABCG2, and ABCC2 polymorphisms. Based on the area under the receiver-operating characteristic curve, the threshold afatinib AUC0-24 value for prediction of dose reduction or withdrawal was 689 ng·h/mL at the best sensitivity (81.0%) and specificity (72.7%). In multivariate logistic regression analysis, an afatinib AUC0-24 above 689 ng·h/mL was independently associated with increased risk of dose reduction or withdrawal (OR: 11.66, P = 0.012).

CONCLUSIONS

The NR1I2 7635A allele was related to a lower afatinib CL/F. Based on the AUC of 689 ng h/mL and CL/F, the optimal doses for patients with the NR1I2 7635G/G genotype and 7635A allele were recommended to be set at 40 and 30 mg/day, respectively, and subsequent adjustment of the maintenance dose based on the plasma concentrations of afatinib may be necessary to avoid afatinib-related adverse events.

Relationship of Lesion Location to Postoperative Steroid Use in Eosinophilic Chronic Rhinosinusitis

OBJECTIVES

Eosinophilic chronic rhinosinusitis (ECRS) is known to recur after surgery. The treatment choice for recurrent ECRS, such as oral steroids or biological agents, must be chosen carefully, and identifying the lesion location may be useful. This study aimed to evaluate the postoperative course of ECRS patients and assess the relationship between endoscopic lesion location and postoperative oral steroid use.

METHODS

Patients with chronic rhinosinusitis who underwent bilateral endoscopic sinus surgery from April 2018 to March 2020 were divided into two groups based on the presence or absence of oral steroid use after surgery. The primary endpoint was the lesion location on endoscopic findings during surgery: middle turbinate, middle meatus, superior turbinate, superior meatus, nasal septum, and sphenoethmoidal recess. Subjective symptoms, blood tests, and computerized tomography (CT) findings (Lund-Mackay score) were evaluated as secondary endpoints.

RESULTS

Among 264 patients, 88 were diagnosed histologically with ECRS (mean 48.98 ± 1.40 years, 67 males/21 females). Twenty-three patients were steroid-using, 65 were steroid-free, and six stopped attending their appointments. Patients with sphenoethmoidal recess lesions were significantly more likely to require steroids (p = 0.019). There was a significant association between steroid use and younger age (p = 0.041), olfactory dysfunction (p = 0.021), and all sinuses (Frontal sinus: p < 0.001, Anterior ethmoid sinus: p = 0.002, Posterior ethmoid sinus: p = 0.011, Maxillary sinus: p = 0.018, Sphenoid sinus: p = 0.034, Total score: p < 0.001).

CONCLUSION

A sphenoethmoidal recess lesion was a risk factor for requiring postoperative steroids. Young age, olfactory dysfunction, and preoperative severe CT findings were also significant risk factors.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:2511-2516, 2023.

A Prospective Cohort Study Assessing the Relationship between Plasma Levels of Osimertinib and Treatment Efficacy and Safety

Osimertinib is a standard treatment for patients with EGFR-mutated non-small cell lung carcinoma (NSCLC). We evaluated the relationship between plasma osimertinib concentrations and treatment outcome in patients with NSCLC for this cohort study. The plasma levels of osimertinib and its metabolite AZ5104 were measured a week after the start of treatment (P1). The primary endpoint was to evaluate the correlation between plasma concentration and adverse events (AEs). The correlation with treatment efficacy was one of the secondary endpoints. In patients with CNS metastases, the concentration in the cerebrospinal fluid was also measured. Forty-one patients were enrolled. The frequency of AEs was highest for rash, followed by anorexia and thrombocytopenia. Thirty-eight cases provided measurements for P1. The median plasma concentration of osimertinib was 227 ng/mL, and that of AZ5104 was 16.5 ng/mL. The mean CNS penetration rate of two cases was 3.8%. The P1 in the group with anorexia was significantly higher than that in the group without anorexia (385.0 ng/mL vs. 231.5 ng/mL, p = 0.009). Divided into quartiles by P1 trough level, Q2 + Q3 (164-338 ng/mL) had longer PFS, while Q1 and Q4 had shorter PFS. An appropriate plasma level of osimertinib may avoid some adverse events and induce long PFS. Further large-scale trials are warranted.

Measurements of neutrino oscillation parameters from the T2K experiment using 3.6×1021 protons on target

The T2K experiment presents new measurements of neutrino oscillation parameters using 19.7 ( 16.3 ) × 10 20 protons on target (POT) in (anti-)neutrino mode at the far detector (FD). Compared to the previous analysis, an additional 4.7 × 10 20 POT neutrino data was collected at the FD. Significant improvements were made to the analysis methodology, with the near-detector analysis introducing new selections and using more than double the data. Additionally, this is the first T2K oscillation analysis to use NA61/SHINE data on a replica of the T2K target to tune the neutrino flux model, and the neutrino interaction model was improved to include new nuclear effects and calculations. Frequentist and Bayesian analyses are presented, including results on sin 2 θ 13 and the impact of priors on the δ CP measurement. Both analyses prefer the normal mass ordering and upper octant of sin 2 θ 23 with a nearly maximally CP-violating phase. Assuming the normal ordering and using the constraint on sin 2 θ 13 from reactors, sin 2 θ 23 = 0 . 561 - 0.032 + 0.021 using Feldman-Cousins corrected intervals, and Δ m 32 2 = 2 . 494 - 0.058 + 0.041 × 10 - 3 eV 2 using constant Δ χ 2 intervals. The CP-violating phase is constrained to δ CP = - 1 . 97 - 0.70 + 0.97 using Feldman-Cousins corrected intervals, and δ CP = 0 , π is excluded at more than 90% confidence level. A Jarlskog invariant of zero is excluded at more than 2 σ credible level using a flat prior in δ CP , and just below 2 σ using a flat prior in sin δ CP . When the external constraint on sin 2 θ 13 is removed, sin 2 θ 13 = 28 . 0 - 6.5 + 2.8 × 10 - 3 , in agreement with measurements from reactor experiments. These results are consistent with previous T2K analyses.

腎移植患者におけるミコフェノール酸血中濃度に対する高速液体クロマトグラフLM1010の精度評価

Plasma concentrations of mycophenolic acid (MPA), an immunosuppressive agent, have been measured in clinical settings using immunoassay methods or HPLC. However, immunoassay methods show cross-reactivity with metabolites of MPA glucuronide. Recently, the LM1010 high-performance liquid chromatography instrument was approved as a new general medical device. In this study, we compared the results of MPA plasma concentrations analyzed using the LM1010 method and the previously described HPLC method. Plasma samples obtained from 100 renal transplant patients (32 women and 68 men) were evaluated using both HPLC instruments. Deming regression analyses showed a very high correlation between the two instruments, with a slope of 0.9892 and an intercept of 0.0235 µg/mL (r²=0.982). Bland-Altman analysis showed an average of -0.0012 µg/mL between the LM1010 method and the previously described HPLC method. For the LM1010 method, the total run time for MPA analysis was 7 min, and the analytical time was short; however, the extraction recovery when using a spin column was extremely low for frozen plasma samples stored at -20°C for 1 month, and the volume required for the assay (150 µL) could not be collected. Thus, for the LM1010 method, analysis using fresh plasma samples was optimal. Overall, our findings showed that the LM1010 method was a rapid, accurate HPLC assay for MPA analysis and could be used in clinical practice for routine monitoring of MPA in fresh plasma samples.

Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande

We report a search for cosmic-ray boosted dark matter with protons using the 0.37  megaton×years data collected at Super-Kamiokande experiment during the 1996-2018 period (SKI-IV phase). We searched for an excess of proton recoils above the atmospheric neutrino background from the vicinity of the Galactic Center. No such excess is observed, and limits are calculated for two reference models of dark matter with either a constant interaction cross section or through a scalar mediator. This is the first experimental search for boosted dark matter with hadrons using directional information. The results present the most stringent limits on cosmic-ray boosted dark matter and exclude the dark matter-nucleon elastic scattering cross section between 10^{-33}cm^{2} and 10^{-27}cm^{2} for dark matter mass from 1  MeV/c^{2} to 300  MeV/c^{2}.

[Determination of Plasma Concentrations of Imatinib by a Novel Automated Analyzer Based on High-Performance Liquid Chromatography]

LM1010 HPLC is an emerging automated method designed for use in clinical settings. The aim of this study was to compare the analytical performance of LM1010 with the performance of traditional HPLC and LC-MS/MS in the measurement of plasma concentrations of imatinib. Seventy-eight plasma samples from 20 patients (14 men and 6 women) were collected. Plasma concentrations of imatinib in samples from the same patient were analyzed simultaneously using LM1010, HPLC and LC-MS/MS (LSI Medience Corporation). Strong correlations were seen in pairwise comparisons of results from the LM1010 and HPLC methods, the LM1010 and LC-MS/MS methods, and the LC-MS/MS and HPLC methods (Spearman's r=0.936, 0.906, and 0.953, respectively); however, the results from the LC-MS/MS method showed a positive proportional bias in comparison with the results from the LM1010 and HPLC methods, according to Deming analyses (slope=1.064 and 1.105, respectively). In Bland-Altman analyses, the LC-MS/MS method showed a positive mean bias of 98.6 and 112 ng/mL in comparison with the LM1010 and HPLC methods, respectively. Notably, results obtained using the LM1010 method were comparable to those using the HPLC method (positive mean bias=13.6 ng/mL; 95% confidence interval, -7.9-35.1 ng/mL). Biochemical parameters or drugs taken concomitantly with imatinib were not found to affect the bias of the LM1010 method. The LM1010 method can be applied to routine therapeutic drug monitoring of imatinib.

Effects of ABCB1 polymorphisms on the transport of ponatinib into the cerebrospinal fluid in Japanese Philadelphia chromosome-positive acute lymphoblastic leukaemia patients

The effects of polymorphisms of ABCB1 and ABCG2 on the dose-adjusted plasma trough concentrations and cerebrospinal fluid (CSF)-to-plasma ratios of ponatinib were evaluated. Blood (C₄ ) and CSF (CSF₄ ) concentrations at 4 h after administration were determined. The median (95% confidence interval) CSF₄ -to-C₄ ratio of ponatinib in subjects homozygous for ABCB1 variants 1236T/T, 2677T/T + T/A or 3435T/T were significantly higher than that in a group of subjects with other genotypes (P = .026, .012 and .015, respectively). The median (95% confidence interval) CSF₄ -to-C₄ ratio of ponatinib in 4 patients with the combination of ABCB1 variants 1236T/T-2677T/T + T/A-3435T/T was 2.62% (1.42-3.42%); this ratio was significantly higher than that in subjects with other genotypes (1.08% [0.89-1.47%]; P = .006). The brain distribution of ponatinib was affected by ABCB1 polymorphisms and therefore seems to be modulated by P-glycoprotein at the blood-brain and blood-CSF barriers.

Efficacy and safety of pemafibrate versus bezafibrate in coronary artery disease patients receiving statin treatment: a randomized, open-label, cross-over study

Background

Fibrates activate peroxisome proliferator-activated receptor (PPAR)-α which is associated with lipid metabolism. Bezafibrate is a non-selective PPAR-α agonist, whereas pemafibrate has been developed as a higher selective PPAR-α agonist.

Objective

The efficacy and safety of pemafibrate for 24-week in patients with dyslipidemia was examined in comparison with bezafibrate.

Methods

Sixty patients with hypertriglyceridemia (fasting triglyceride (TG) level of ≥150 mg/dL) were treated with pemafibrate of 0.2 mg/day or bezafibrate of 400 mg/day for 24-week in a randomized cross-over study. Percent change from baseline in TG levels was the primary endpoint, and that in HDL-C and apolipoprotein A-I (Apo A-I) levels was the secondary endpoints.

Results

A significantly greater reduction in TG percent change was observed in pemafibrate than in bezafibrate (−46.1% vs. −34.7%, p&lt;0.001). There was no significant difference in HDL-C percent change between pemafibrate and bezafibrate (18.4% vs. 14.0%, p=0.067), whereas Apo A-I percent change was significantly greater in pemafibrate than in bezafibrate (9.2% vs. 5.7%, p=0.018). Pemafibrate and bezafibrate significantly decreased alanine aminotransferase (ALT) and gamma-glutamyltransferase (γ-GT) levels, and pemafibrate showed a greater reduction than bezafibrate (ALT: −21.9% vs. −10.6%, p=0.048; γ-GT: −43.5% vs. −33.1%, p=0.025). Creatinine levels significantly increased in both treatments (both p&lt;0.001), however, creatinine percent change was significantly smaller in pemafibrate than in bezafibrate (5.72% vs. 15.5%, p&lt;0.001). There was no difference in frequency of adverse event (AE) or serious AE between two treatments, but frequency of creatinine elevation (≥0.5 mg/d and/or 25%) was significantly higher in bezafibrate than in pemafibrate (16/60 vs. 3/60, p=0.004).

Conclusion

As compared with bezafibrate, pemafibrate is more effective to reduce TG levels and to elevate Apo A-I levels, and it is safer in terms of liver and renal function.

Funding Acknowledgement

Type of funding sources: None.

Effects of CYP3A4/5 and ABC transporter polymorphisms on osimertinib plasma concentrations in Japanese patients with non-small cell lung cancer

The effects of polymorphisms in CYP3A4 (20230G > A), CYP3A5 (6986A > G), ABCB1 (1236C > T, 2677G > T/A, 3435C > T), ABCG2 (421C > A), and ABCC2 (-24C > T) on the area under the concentration-time curve (AUC) of osimertinib in 23 patients with non-small cell lung cancer were investigated. Blood sampling was performed just prior to and at 1, 2, 4, 6, 8, 12, and 24 h after osimertinib administration at the steady-state on day 15 after beginning therapy. The osimertinib AUC_0-24 was significantly correlated with age (P = 0.038), serum albumin (P = 0.002), and serum creatinine (P = 0.012). Additionally, there were significant differences in the AUC_0-24 of osimertinib among the groups administered vonoprazan, histamine 2-receptor antagonists or esomeprazole, and no acid suppressants (P = 0.021). By contrast, there were no significant differences in the AUC_0-24 of osimertinib between genotypes of CYP3A4/5 or ABC transporters. Furthermore, there were no significant differences in the AUC_0-24 of osimertinib between patients with diarrhea, skin rash, or hepatotoxicity and those without these conditions. In multivariate analysis, only serum albumin value was an independent factor predicting the AUC_0-24 of osimertinib. Analysis of CYP3A4/5 and ABC transporter polymorphisms before osimertinib therapy may not predict the efficacy or side effects of osimertinib. The lower serum albumin values were associated with an increase in the AUC_0-24 of osimertinib; however, further studies are needed to assess the factors contributing to the interindividual variability of osimertinib pharmacokinetics.

P-039 Male age is associated with sperm DNA integrity: Selection of high DNA integrity sperm by microfluidics sorting is critical to clinical outcomes in older patients

Study question

Does sperm DNA integrity affect clinical outcomes of ICSI?

Summary answer

Use of high DNA integrity sperm selected by microfluidics sperm sorting results in lower miscarriage rates in the patients of 39-years old and more.

What is known already

High sperm DNA damage is associated with decreased normal fertilization, embryo development and pregnancy rates, and an increased miscarriage rate. On the other hand, oocytes from older women have decreased pregnancy rate, and increased miscarriage rate because of possibility of low ability to repair sperm with DNA fragmentation, and dramatical increases of aneuploidy as women age. A microfluidic sperm selection chamber (MSS, ZyMōt™; DxNow) is a device designed to collect sperm with higher chromatin integrity than density gradient centrifugation (DGC).

Study design, size, duration

Sperm analysis was performed by sperm chromatin dispersion (SCD) test and comet assay in the same sample of 15 cases between October 2020 and February 2021. ICSI outcomes by DGC and MSS were compared with blastocyst development, and pregnancy rates in vitrified-thawed single blastocyst transfers cycle for 518 cases between August 2018 and May 2021.

Participants/materials, setting, methods

SCD test was optimized as a rapid procedure, with sperm showing a halo deemed normal, and those without a halo abnormal. Comet assay results were analyzed using CometScore 2.0, with comparison of %Tail DNA. ICSI outcomes were analyzed using multiple logistics regressions of male and female ages.

Main results and the role of chance

We found a positive correlation between male age and sperm DNA fragmentation rates in raw semen using SCD test (r = 0.70) and Comet assay (r = 0.42). Higher DNA integrity sperm could select using MSS than DGC. In this study with ICSI outcomes, 170 of 318 (53.5%) blastocyst transfers resulted in pregnancy, and 49 (28.8%) subsequently miscarried. The data were classified according to less than or more than 39 years old of male age detected by multiple logistics regressions. In patients with ≥39 years of male age, the female age was significantly higher and blastocyst and pregnancy rates were significantly lower, and the miscarriage rate was significantly higher than &lt;39 years of male age. Since sperm DNA fragmentation increased in accordance with male age, we compared MSS and DGC in the patients with male age ≥39 years. There was no significant difference in blastocyst, pregnancy, and miscarriage rates in female age &lt;39 years. While in ≥ 39 years of female age, blastocyst and pregnancy rates in MSS were not significantly different from DGC, but the miscarriage rate in MSS was significantly lower than in DGC (27.3 vs. 57.1%).

Limitations, reasons for caution

The sample size for each study was small. Analysis of sperm DNA fragmentation and samples in ICSI outcomes were not the same. The retrospective nature of ICSI outcomes in this study does not allow controlling of unknown confounders.

Wider implications of the findings

Sperm DNA fragmentation depended on male age affected fertility outcomes. However, when male age is higher, masking the effect of male age by female age. In this study, we found out the improvement of ICSI outcome by using high DNA integrity sperm selected by MSS in both ≥39 years.

Trial registration number

Not applicable

The orthostatic hypotension in patients with Stanford type A aortic dissection after surgery

Funding Acknowledgements

Type of funding sources: None.

Background

Orthostatic hypotension (OH) is sometimes observed during cardiac rehabilitation in patients with surgery for aortic dissection. However, little is known about the primary determinant of OH and influence of surgical range on incidence of OH.

Purpose

The aim of this study was to elucidate the incidence of OH in patients with surgery for aortic dissection, and compare it between the patients with ascending aortic replacement surgery (ascending group) and those with ascending aorta and hemiarch or total arch replacement surgery (arch group).

Methods

We analyzed 59 patients who underwent emergent surgery due to Stanford type A aortic dissection from January 2014 to March 2018, and compared the incidence of OH between ascending group (n = 28, age 69.8 ± 11.3 years) and arch group (n = 31, age 64.1 ± 13.0 years).

Results

The incidence of OH in total patients was 30.5%. There were no significant differences in patient characteristics including body tall, body weight, antihypertensive use and progress of rehabilitation between 2 groups. The arch group showed a significant higher incidence of OH as compared with ascending group (arch group: 46.4% vs. ascending group: 16.1%, p = 0.03). Moreover, the patients who occurred OH were significantly taller than those who did not occur OH.

Conclusions

OH was observed in about one third of patients with surgery for aortic dissection and it showed a close relationship with patient’s height and the range repaired by surgical operation. More careful cardiac rehabilitation is needed for tall patients with large area replacement of aorta.

Associations Between Plasma Concentrations of Lenvatinib and Angiopoietin and Clinical Responses to Lenvatinib Therapy in Japanese Patients With Thyroid Cancer

BACKGROUND/AIM

The purpose of this study was to investigate the relationships between the plasma concentration of Lenvatinib (C0), the levels of angiopoietin (Ang)-1 and Ang-2, and clinical responses to lenvatinib therapy in patients with thyroid cancer.

PATIENTS AND METHODS

Lenvatinib C ₀ and Ang were measured by high-performance liquid chromatography and enzyme-linked immunosorbent assay, respectively.

RESULTS

The median decrease rates of Ang-1 and Ang-2 at 1 month after treatment from baseline were -15.3% and -48.4%, respectively. However, the decrease in the levels of Ang-1 and Ang-2 at 1 month from baseline did not correlate with C0. In patients with partial response (PR) and stable disease, Ang-2 at 1 month was significantly lower than Ang-2 at baseline. The area under the ROC for PR prediction was 0.667, giving the best sensitivity (69.2%) and specificity (73.9%) at a threshold of decrease rate of Ang-2 of -49.83%.

CONCLUSION

The decrease in Ang-2 at 1 month of treatment from baseline may be important as a biomarker of the inhibitory effect of lenvatinib on angiogenesis.

Relationship between achievement of major molecular response or deep molecular response and nilotinib plasma concentration in patients with chronic myeloid leukemia receiving first-line nilotinib therapy

PURPOSE

We evaluated the plasma exposure and response relationships of nilotinib for patients with newly diagnosed chronic myeloid leukemia (CML) in real-world practice.

METHODS

For the 26 patients enrolled in this study, at 3, 6, 12, and 24 months after nilotinib administration, the trough plasma concentrations (C_trough) of nilotinib were analyzed. The relationships between nilotinib C_trough and the molecular response to nilotinib treatment at each point (each n = 26) were evaluated.

RESULTS

Median nilotinib C_trough values were significantly higher in patients with a major molecular response (MMR) at 3 months than in patients without an MMR (809 and 420 ng/mL, respectively; P = 0.046). Based on the area under the receiver-operating characteristic curve, the threshold value of the nilotinib C_trough at 3 months for predicting MMR achievement was 619 ng/mL at the best sensitivity (71.4%) and specificity (77.8%). Patients with a nilotinib C_trough of above 619 ng/mL had a significantly shorter time to achievement of a deep molecular response (DMR; 9.0 and 18.0 months, respectively; P = 0.020) and higher rates of DMR by 2 years in Kaplan-Meier plots (P = 0.025) compared with that in patients with a nilotinib C_trough of less than 619 ng/mL.

CONCLUSION

For patients with newly diagnosed CML, the nilotinib dose may be adjusted using a C_trough of above 619 ng/mL as the minimum effective concentration, i.e., the lowest concentration required for MMR or DMR achievement within a shorter time, during early stages after beginning therapy to obtain faster and deeper clinical responses.

Increased plasma drug concentration and decreased additional insulin secretion following oral administration of glimepiride in Spontaneously Diabetic Torii rats

We aimed to evaluate the pharmacokinetics and pharmacological effects of glimepiride in the Spontaneously Diabetic Torii (SDT) rat, which is a non-obese model of type 2 diabetes. After oral administration of glimepiride (10 mg/kg), the maximum plasma concentrations and the area under the curve from 0 to 6 h of glimepiride in SDT rats were significantly higher than those in age-matched Sprague-Dawley rats. Whereas, additional insulin secretion following glimepiride treatment was markedly reduced in SDT rats. Thus, the SDT rat can be regarded as a model that reflects type 2 diabetes with reduced insulin secretory capacity. Our findings suggested that glimepiride could be ineffective in sever type 2 diabetic patients.

Regulatory T Cell as a Biomarker of Treatment-Free Remission in Patients with Chronic Myeloid Leukemia

Treatment-free remission (TFR) has become a therapeutic goal in chronic myeloid leukemia (CML), and approximately half of the patients with chronic phase-CML (CML-CP) with deep molecular remission (DMR) by tyrosine-kinase inhibitors (TKIs) have achieved TFR. However, the mechanism of continuous TFR is still unclear, as there are "fluctuate" patients who have BCR-ABL-positive leukemia cells but do not observe obvious relapse. We focused on the immune response and conducted an immune analysis using clinical samples from the imatinib discontinuation study, JALSG-STIM213. The results showed that, in the group that maintained TFR for 3 years, changes in regulatory T (Treg) cells were observed early after stopping imatinib treatment. The effector Treg (eTreg) cells increased transiently at 1 month after stopping imatinib and then returned to baseline at 3 months after stopping imatinib treatment. There was no difference in the Treg phenotype, and CD8+ T cells in the TFR group were relatively activated. High concentrations of imatinib before stopping were negatively correlated with eTreg cells after stopping imatinib. These data suggest immunological involvement in the maintenance of the TFR, and that Treg cells after stopping imatinib might be a biomarker for TFR. Furthermore, high imatinib exposure may have a negative immunological impact on the continuous TFR.

Lactational performance and plasma and muscle amino acid concentrations in dairy cows fed diets supplying 2 levels of digestible histidine and metabolizable protein

The objective of this experiment was to investigate the effect of dietary levels of digestible histidine (dHis) and MP on lactational performance and plasma and muscle concentrations of free AA in dairy cows. A randomized block design experiment was conducted with 48 Holstein cows, including 20 primiparous, averaging (±SD) 103 ± 22 d in milk and 45 ± 9 kg/d milk yield at the beginning of the experiment. A 2-wk covariate period preceded 12 experimental wk, of which 10 wk were for data and sample collection. Experimental treatments were (1) MP-adequate (MPA) diet with 2.1% dHis of MP (MPA2.1), (2) MPA with 3.0% dHis (MPA3.0), (3) MP-deficient (MPD) diet with 2.1% dHis (MPD2.1), and (4) MPD with 3.0% dHis (MPD3.0). Actual dHis supply was estimated at 64, 97, 57, and 88 g/d, respectively. Diets supplied MP at 110% (MPA) and 96% (MPD) of NRC 2001 dairy model requirements calculated based on DMI and production data during the experiment. Dry matter intake and milk yield data were collected daily, milk samples for composition and blood samples for AA analysis were collected every other week, and muscle biopsies at the end of covariate period, and during wk 12 of the experiment. The overall DMI was not affected by dHis or MP level. Milk yield tended to be increased by 3.0% dHis compared with 2.1% dHis. Milk true protein concentration and yield were not affected by treatments, whereas milk urea nitrogen concentration was lower for MPD versus the MPA diet. Milk fat concentration was lower for MPD versus MPA. There was a MP × dHis interaction for milk fat yield and energy-corrected milk; milk fat was lower for MPD3.0 versus MPD2.1, but similar for cows fed the MPA diet regardless of dHis level whereas energy-corrected milk was greater for MPA3.0 versus MPA2.1 but tended to be lower for MPD3.0 versus MPD2.1. Plasma His concentration was greater for cows fed dHis3.0, and concentration of sum of essential AA was greater, whereas carnosine, 1-Methyl-His and 3-Methyl-His concentrations were lower for cows fed MPA versus MPD diet. Muscle concentration of His was greater for cows fed dHis3.0 treatment. The apparent efficiency of His utilization was increased at lower MP and His levels. Overall, cows fed a corn silage-based diet supplying MP at 110% of NRC (2001) requirements tended to have increased ECM yield and similar milk protein yield to cows fed a diet supplying MP at 96% of requirements. Supplying dHis at 3.0% of MP (or 86 and 96 g/d, for MPD3.0 and MPA3.0, respectively) tended to increase milk yield and increased plasma and muscle concentrations of His but had minor or no effects on other production variables in dairy cows.

Muscle stretching induces twitch contractions without activation of stretch-activated channels in intact rat trabeculae

Introduction

Mechano-electric coupling (MEC) means that muscle stretching can induce action potentials. Stretch-activated channels (SACs) have been believed to play important roles in their induction.

Purpose

To investigate what degree of muscle stretching can induce MEC-mediated action potentials and what roles SACs play in their induction.

Methods

Trabeculae were obtained from right ventricles of rat hearts. Force was measured with a strain gauge, sarcomere length (SL) with a laser diffraction technique, and [Ca2+]i with fura-2 (24°C). The SL was set at 2.0 μm at the resting condition. Trabeculae were stimulated electrically at 400-ms intervals for 7.5 s. Various degrees of muscle stretching were applied at 500 ms after the last stimulus of the electrical train to determine the minimal SL (SL-AP) at which an action potential or a twitch contraction was induced by the stretching (0.7 mM [Ca2+]o).

Results

The SL-AP was 2.34±0.02 μm (n=8) when trabeculae were stretched rapidly from a SL of 2.0 μm (400-ms stimulation intervals, 0.7 mM [Ca2+]o). The SL-AP was not changed by increasing the stimulation intervals from 400 to 2000 ms (n=7), by increasing [Ca2+]o from 0.7 to 2 mM (n=8), and by adding 1 μM isoproterenol (n=8), suggesting that Ca2+ loading within the myocardium has no effect on the SL-AP. Surprisingly, the SL-AP was not changed by adding 5 μM GsMTx4 (n=8), 10 mM Gd3+ (n=9), 100 μM (n=8) and 200 μM streptomycin (n=11), revealing that SACs play no roles in the determination of SL-AP. The SL-AP was not changed by adding 1 μM ryanodine (n=5) and 30 μM cyclopiazonic acid and was not changed by adding 3 μM diphenyleneiodonium chloride (n=8) and 10 μM colchicine, suggesting that Ca2+ leak from the SR and activation of NADPH oxidase has no effect on the SL-AP. In contrast, elevation of temperature from 23 to 36°C decreased the SL-AP from 2.35±0.01 to 2.34±0.02 μm (p&lt;0.05, n=7). Elevation of extracellular K+ ([K+]o) from 5 to 10 mM increased the SL-AP from 2.35±0.01 to 2.38±0.01 μm (p&lt;0.01, n=7), while reduction of [K+]o to 5 mM decreased it to 2.36±0.01 μm (p&lt;0.05, n=7), suggesting that depolarization of membrane potential suppresses MEC-mediated twitch contractions. The SL-AP was increased from 2.34±0.01 to 2.36±0.01 μm (p&lt;0.01, n=7) when stretching was applied at a shorter interval after the last stimulus, i.e., 200 ms. After electrical stimulation at 300-ms stimulation intervals for 30 s, arrhythmias were induced by a MEC-mediated twitch contraction in 6 out of 9 trabeculae when stretching was applied at 500 ms after the last stimulus, while they were induced only in 2 out of 9 trabeculae without the stretching (4 mM [Ca2+]o, 1 μM isoproterenol).

Conclusions

These results suggest that muscle stretching causes membrane excitation, which potentially induces arrhythmias and that activation of SACs, Ca2+ release from the SR, and activation of NADPH oxidase by muscle stretching are not involved in the excitation.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Grant-in-Aid for Scientific Research (C) from Japan Society for the Promotion of Science.

Serial evaluation of the pharmacokinetics of ponatinib in patients with CML and Ph + ALL

Although tyrosine kinase inhibitors (TKIs) play a crucial role in the treatment of chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph + ALL), intolerance and resistance to TKIs have been serious problems. Due to a lack of research, the importance of the pharmacokinetics (PK) of TKIs is currently unclear. We examined the PK of the third-generation TKI ponatinib to monitor side effects and efficacy during treatments for one patient with CML-chronic phase (CP-CML) and two who received allogeneic hematopoietic stem cell transplantation (allo-HSCT), one for CML-blastic crisis (BC-CML) and one for Ph + ALL. The patient with CP-CML was intolerant to multiple TKIs (dasatinib, nilotinib, imatinib, and bosutinib) and thus was switched to ponatinib (15 mg/day). The patients who received allo-HSCT for BC-CML and Ph + ALL received ponatinib (15 mg/day) as maintenance therapy. Notably, serial evaluation of the PK of ponatinib showed that the median trough values (ng/ml) were 17.2 (12.2-34.5), 33.1 (21.2-40.3) and 27.7 (13.6-29.9) in patients 1, 2, and 3, respectively. These values were around the target concentration (23 ng/ml). All patients are maintaining complete remission without side effects. In conclusion, serial evaluation of PK of ponatinib may yield meaningful information about its safety and efficacy.

CMR feature tracking cloud assess right ventricular functional reserve with pulmonary arterial hypertension

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): JSPS KAKENHI, Grant-in-Aid for Early-Career Scientists.

Background

  Pulmonary arterial hypertension (PAH) remains a fatal disorder characterized by elevated pulmonary arterial pressure. Survival of the patients with PAH is determined from right ventricular (RV) function. CMR has become an attractive modality for following up and providing prognosis in such patients, and CMR feature tracking has been used as a newer useful parameter to assess RV function. However, it has not yet been determined whether CMR feature tracking can assess RV functional reserve in patients with PAH.

Purpose

We investigated whether CMR feature tracking can estimate RV functional reserve using a rat model with PAH.

Methods

 Rats were received injections with monocrotaline (MCT-rats, n = 19) or solvent (Ctr-rats, n = 5). Four weeks after the injections, we performed CMR on 7-T MRI scanner and imaged retrospective ECG-gated cine MR (16 phases/beat). RV ejection fraction (RVEF) and RV strain were analyzed before and after addition of 0.5∼3 nmol endothelin-1 (ET-1). After the measurements, we dissected trabeculae (length = 1.45 ± 0.07 mm, width = 334 ± 27 µm, thickness = 114 ± 6 µm) from the RVs of rat hearts. Trabeculae were electrically stimulated with 2-s intervals at extracellular Ca2+ of 0.7 and 2.0 mmol/L (24°C). Force and maximum dF/dt (dF/dtmax) were then measured using a silicon strain gauge in the absence and presence of 0.1 µM ET-1.

Results

 MCT-rats showed higher systolic RV pressure (RVP), lower RVEF, and lower RV global longitudinal strain (RVGLS) in CMR imaging and showed lower developed force and lower dF/dtmax in their trabeculae. Correlation between RVGLS and dF/dtmax was higher (r = 0.53, p &lt; 0.05) than that between RVEF and dF/dtmax (r = 0.24). In 5 MCT-rats with preserved RVEF (&gt;50%), RVGLS had already been reduced, suggesting that RVGLS is reduced earlier than RVEF. ET-1 increased developed force and dF/dtmax in trabeculae from MCT-rats (12.2 ± 5.7 to 17.4 ± 3.1 mN/mm2 and 0.08 ± 0.03 to 0.14 ± 0.06 mN/mm2/sec, respectively, n = 6), and ET-1 also increased RVP in MCT-rats and Ctr-rats (49.0 ± 19.3 to 59.7 ± 16.8 mmHg in MCT-rats, n = 6, 17.3 ± 7.5 to 20.4 ± 7.8 mmHg in Ctr-rats, n = 2). According to RV global circumferential strain (RVGCS) and RVEF, we could divide MCT-rats into three groups as follows: MCT-rats with reduced-RVGCS (&gt; -20%)/preserved-RVEF (&gt; 50%), MCT-rats with increased-RVGCS (&lt; -30%)/preserved-RVEF and MCT-rats with reduced-RVGCS/reduced-RVEF. ET-1 reduced RVGCS in MCT-rats with reduced-RVGCS/preserved-RVEF, while ET-1 did not change RVGCS in MCT-rats with increased-RVGCS/preserved-RVEF. MCT-rats with reduced-RVGCS/reduced-RVEF died after injection of ET-1.  In Ctr-rats, ET-1 did not change RVGCS and RVEF.  These results suggest that RVGCS can be useful to assess RV functional reserve.

Conclusion

 CMR feature tracking can estimate RV functional reserve earlier and more accurately than RVEF in rats with PAH.  RV strain may become an important parameter to assess RV functional reserve in patients with PAH.

Dietary starch level and rumen-protected methionine, lysine, and histidine: Effects on milk yield, nitrogen, and energy utilization in dairy cows fed diets low in metabolizable protein

Our objective was to investigate the interactions between starch level and rumen-protected Met, Lys, His (RP-MLH) on milk yield, plasma AA concentration, and nutrient utilization in dairy cows fed low metabolizable protein diets (mean = -119 g/d of metabolizable protein balance). Sixteen multiparous Holstein cows (138 ± 46 d in milk, 46 ± 6 kg/d in milk) were used in a replicated 4 × 4 Latin square with a 2 × 2 factorial arrangement of treatments. Each period lasted 21 d with 14 d for diet adaptation and 7 d for data and sample collection. Dietary starch level varied by replacing (dry matter basis) pelleted beet pulp and soyhulls with ground corn resulting in the following treatments: (1) 20% pelleted beet pulp and 10% soyhulls (reduced starch = RS), (2) RS plus RP-MLH (RS+AA), (3) 30% ground corn (high starch = HS), and (4) HS plus RP-MLH (HS+AA). Dietary starch concentrations averaged 12.3 and 34.4% for RS and HS basal diets, respectively. Diets were supplemented with RP-MLH products to supply digestible Met, Lys, and His. Compared with RS and RS+AA diets, HS and HS+AA diets increased yields of milk (37.9 vs. 40.1 kg/d) and milk protein (1.07 vs. 1.16 kg/d) and decreased dry matter intake (25.9 vs. 25.2 kg/d), milk urea N (12.6 vs. 11.0 mg/dL), and plasma urea N (13.3 vs. 11.6 mg/dL). Milk N efficiency was greater in cows fed the HS and HS+AA than RS and RS+AA diets (28.9 vs. 25%), and RP-MLH supplementation improved milk true protein concentration. Starch level × RP-MLH interactions were observed for plasma concentrations of Arg and Lys, with RP-MLH being more effective to increase plasma Arg (+16%) and Lys (+23%) when supplemented to the RS than the HS basal diet. Replacing pelleted beet pulp and soyhulls with ground corn lowered the plasma concentrations of all essential AA except Met and Thr. In addition, the plasma concentrations of His and Met increased with RP-MLH. The apparent total-tract digestibilities of neutral and acid detergent fiber were lower, and those of starch and ether extract greater in cows offered the HS and HS+AA diets than RS and RS+AA diets. Urinary excretion of urea N decreased by replacing pelleted beet pulp and soyhulls with ground corn. Enteric CH₄ production, CH₄ yield, and CH₄ intensity all decreased in the HS and HS+AA versus RS and RS+AA diets. Diets did not affect the intakes of gross energy, metabolizable energy, and net energy of lactation. In contrast, digestible energy intake increased with feeding the RS and RS+AA diets, whereas CH₄ energy decreased in cows fed the HS and HS+AA diets. Supplementation with RP-MLH had no effect on energy utilization variables. Overall, the lack of interactions between dietary starch level and RP-MLH supplementation on most variables measured herein showed that the effects of starch intake and RP-MLH were independent or additive.

Histidine dose-response effects on lactational performance and plasma amino acid concentrations in lactating dairy cows: 1. Metabolizable protein-adequate diet

The objective of this experiment was to determine the effect of increasing digestible His (dHis) doses on milk production, milk composition, and plasma AA concentrations in lactating dairy cows fed diets that meet or exceed their energy and metabolizable protein (MP) requirements. In a companion paper (Räisänen et al., 2021) results are presented on the effect of increasing dHis dose with an MP-deficient basal diet. In this experiment, 16 Holstein cows (72 ± 15 d in milk) were used in a replicated 4 × 4 Latin square design experiment with four 28-d periods. Treatments were as follows: (1) control, total mixed ration (TMR) with 1.8% dHis of MP (TMR1; dHis1.8); (2) a different TMR with 2.2% dHis (TMR2; dHis2.2); (3) TMR2 supplemented with rumen-protected His (RP-His) to supply 2.6% dHis (dHis2.6); and (4) TMR2 supplemented with RP-His to supply 3.0% dHis of MP (dHis3.0). Estimated dHis intakes calculated at the end of the experiment were 46, 58, 69, and 79 g/d for dHis1.8, dHis2.2, dHis2.6, and dHis3.0, respectively. Contrasts were used to compare TMR1 with TMR2 and to test the linear and quadratic effects of RP-His inclusion rate on TMR2. We detected no effects of TMR or dHis dose on dry matter intake or milk yield, whereas energy-corrected milk (ECM) yield was quadratically increased, being greatest for cows on treatment dHis2.6. Milk true protein and lactose concentrations and milk true protein yield were not affected by TMR or dHis dose. Milk fat concentration and yield increased quadratically, and lactose yield tended to increase quadratically with increasing dHis dose. Calculated apparent efficiency of His utilization decreased quadratically with increasing dHis supply. Further, plasma concentration of His was greater for cows on TMR2 compared with TMR1. When an MP-adequate diet was fed to dairy cows, milk true protein concentration and yield were not affected by dHis supply, but milk fat and ECM yields of dairy cows were optimized at dHis supply of 69 g/d or 2.65% of MP.

Histidine dose-response effects on lactational performance and plasma amino acid concentrations in lactating dairy cows: 2. Metabolizable protein-deficient diet

The objective of this experiment was to determine the effect of increasing digestible His (dHis) levels with a rumen-protected (RP) His product on milk production, milk composition, and plasma AA concentrations in lactating dairy cows fed a metabolizable protein (MP)-deficient diet, according to the National Research Council dairy model from 2001. The companion paper presents results on the effect of increasing dHis dose with a MP-adequate basal diet. Twenty Holstein cows, of which 8 were rumen-cannulated, were used in a replicated 4 × 4 Latin square design experiment with four 28-d periods. Treatments were a control diet supplying 1.8% dHis of MP or 37 g/d (dHis1.8) and the control diet supplemented RP-His to provide 2.2, 2.6, or 3.0%, dHis of MP, or 53, 63, and 74 g/d (dHis2.2, dHis2.6, and dHis3.0, respectively). Histidine dose did not affect dry matter intake, but milk yield increased quadratically and energy-corrected milk yield increased linearly with increasing dHis dose. Histidine dose had a quadratic effect on milk fat concentration but did not affect milk fat yield. Lactose concentration decreased linearly, whereas lactose yield increased linearly with increasing dHis dose. There was a tendency for a linear increase in milk true protein concentration, and milk true protein yield increased linearly with dHis dose. Further, plasma His concentration increased linearly with increasing dHis dose and calculated apparent efficiency of His utilization decreased quadratically with increasing dHis supply. Histidine had minor or no effects on rumen fermentation. In the conditions of this experiment, RP-His supplementation of an MP-deficient corn silage-based diet increased milk yield linearly up to a dHis supply of 63 g/d (or 2.6% dHis of MP) and increased feed efficiency, energy-corrected milk yield and milk true protein yield linearly up to a dHis supply of 74 g/d (or 3.0% dHis of MP) in lactating dairy cows.

Tacrolimus concentrations after renal transplantation in a mother-neonate dyad: Maternal, neonatal and breast milk measurements

WHAT IS KNOWN AND OBJECTIVE

We aim to add to the few reports on tacrolimus concentrations in breast milk and in maternal, umbilical vein and neonatal blood after maternal renal transplantation.

CASE SUMMARY

In a 30-year-old pregnant woman, the tacrolimus concentration at delivery was the same in maternal, umbilical vein and neonatal blood. The breast milk/maternal blood tacrolimus ratio ranged from 0.40 to 0.64.

WHAT IS NEW AND CONCLUSION

The maternal and neonatal blood tacrolimus concentrations at birth are equivalent; thus, one must assume that maternal tacrolimus concentrations directly affect the foetus and/or neonate. Tacrolimus is not detectable in the neonate 3 weeks after birth, suggesting that there is minimal transfer through breast milk.

Effects on monotherapy and reduction of antipsychotic drugs by clozapine therapy in Japanese patients with treatment-resistant schizophrenia

WHAT IS KNOWN AND OBJECTIVE

The schizophrenia guidelines in Japan and many other countries describe clozapine as the first-choice drug for patients with treatment-resistant schizophrenia. However, there have been no reports to date on the effects of the introduction of clozapine on the prescription of other antipsychotics and concomitant drugs.

METHODS

In this study, we retrospectively investigated the prescription of antipsychotics and concomitant drugs before vs 6 months after and 12 months after switching to clozapine.

RESULTS AND DISCUSSION

Clozapine was introduced to 62 patients with treatment-resistant schizophrenia, and 51 patients continued on clozapine therapy. Six months after switching to clozapine, there was a significant decrease in the mean number of antipsychotic drugs (2.04 ± 0.75 vs 1.10 ± 0.30: p < 0.001) and in the mean chlorpromazine equivalent value (1024 ± 73 mg/day vs 781 ± 391 mg/day: p < 0.001) compared to before switching. Moreover, antipsychotic monotherapy increased from 24% to 90% after switching to clozapine. In addition, the number of concomitant benzodiazepines, anti-parkinson drugs and antidepressants also significantly decreased 6 and 12 months after switching to clozapine (p < 0.001 for benzodiazepines and anti-parkinson drugs, and p < 0.05 for antidepressants).

WHAT IS NEW AND CONCLUSION

Our study suggests that switching to clozapine may reduce the use of antipsychotic combination therapy, and may also reduce the number of concomitant drugs.

Efficacy and safety of ponatinib for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia: a case series from a single institute

Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph + ALL) is an aggressive leukemia that occurs in 20-40% of adult patients. Ph + ALL is caused by the Philadelphia chromosome (Ph), which consists of a t(9;22)(q34;q11) reciprocal translocation leading to the formation of a BCR-ABL1 fusion gene. The disease is treated with targeted therapy comprising ABL1 tyrosine kinase inhibitors (TKIs). Ponatinib is a third generation TKI that demonstrates higher binding affinity for ABL1 than first/second generation TKIs. Although intensive combined immunotherapy with ponatinib greatly improves the prognosis of Ph + ALL, the safety and efficacy profiles of ponatinib in Japanese patients are unclear. This retrospective study investigated five cases of Ph + ALL at a single institute to evaluate safety and efficacy profiles. Three patients achieved a deep molecular response (DMR) following combined intensive treatment with ponatinib as induction chemotherapy. Four patients received consolidative allogenic stem cell transplantation (allo-SCT) during their first complete response. Three of the four experienced early relapse within 100 days; they subsequently received ponatinib, and one of the three achieved a DMR. No patient experienced severe cardiovascular events. This case series suggests that ponatinib at a concentration of least 30 mg exhibits anti-leukemia effects in Japanese patients with Ph + ALL.

Effects of SLC22A2 808G>T polymorphism and bosutinib concentrations on serum creatinine in patients with chronic myeloid leukemia receiving bosutinib therapy

The purpose of this study was to investigate the effects of SLC22A2 808G>T polymorphism and trough concentrations (C₀) of bosutinib on serum creatinine in 28 patients taking bosutinib. At 1, 3, 6, 12, 24, and 36 months after administration, analysis of bosutinib C₀ and creatinine was performed at the same time of day. Significant correlations were observed between bosutinib C₀ and the change rate of serum creatinine or the estimated glomerular filtration rate (eGFR; r = 0.328, P < 0.001 and r = − 0.315, P < 0.001, respectively). These correlations were particularly high in patients having the SLC22A2 808G/G genotype (r = 0.345 and r = − 0.329, respectively); however, in patients having the 808T allele, there were no significant differences. In multivariate analyses, the SLC22A2 808G/G genotype, patient age, bosutinib C₀ and second-line or later bosutinib were independent factors influencing the change rate of creatinine. Bosutinib elevated serum creatinine through organic cation transporter 2 (OCT2). We observed a 20% increase in serum creatinine with a median bosutinib C₀ of 63.4–73.2 ng/mL. Periodic measurement of serum creatinine after bosutinib therapy is necessary to avoid progression to severe renal dysfunction from simple elevation of creatinine mediated by OCT2 following bosutinib treatment.

Results of a nationwide survey of Japanese pharmacists regarding the application of pharmacogenomic testing in precision medicine

WHAT IS KNOWN AND OBJECTIVE

Pharmacogenomics (PGx) testing can be effective for supporting precision medicine. The purpose of this study was to assess the knowledge, attitude and practice behaviours of pharmacists in relation to such testing through a survey. We also aimed to identify potential obstacles to implementation of PGx testing by pharmacists and the characteristics of hospital pharmacists involved.

METHODS

We performed a web-based survey regarding PGx in Japan. The survey contained a questionnaire related to PGx, which consisted of 30 items and was made accessible via the official Japanese Society of Pharmaceutical Health Care and Sciences (JSPHCS) website. The characteristics of hospital pharmacists associated with involvement in PGx testing were evaluated using univariate and multivariate analyses.

RESULTS AND DISCUSSION

One thousand three-hundred and thirteen pharmacists responded to the survey. The results revealed that the majority of respondents recognized the role that germline PGx testing can play in determining individual drug responses and that pharmacists have embraced the potential of PGx testing to improve patient care. However, only 26% of pharmacists were involved in PGx testing. We also found that most respondents (81.0%) believed that the lack of insurance coverage for PGx testing was a major barrier to its clinical implementation. Hospital pharmacists involved in PGx testing included certified pharmacists in JSPHCS and pharmacists who had studied PGx in university; however, only 12.4% of pharmacists had received specific PGx-related education.

WHAT IS NEW AND CONCLUSION

The findings of this survey highlight the necessity to increase the number of PGx tests covered by insurance, and the importance of effective education to inform and facilitate clinical implementation of PGx testing.

Effects of SLC31A1 and ATP7B polymorphisms on platinum resistance in patients with esophageal squamous cell carcinoma receiving neoadjuvant chemoradiotherapy

The relationship between the SLC31A1 (protein: copper transporter 1) rs10981694 A > C and ATP7B (protein: P-type adenosine triphosphatase 7B) rs9535828 A > G polymorphisms on the overall survival and disease-free survival of 104 Japanese patients with esophageal squamous cell carcinoma (ESCC) receiving neoadjuvant chemoradiotherapy (CRT) was investigated. Chemotherapy consisted of protracted infusion of 5-fluoracil (800 mg/m²/day) on days 1-5 and cisplatin or nedaplatin (80 mg/m²/day) on day 1. The median (range) follow-up was 47 (6-127) months. The 5-year overall and disease-free survival rates were 71.2% and 60.6%, respectively. The 5-year overall survival rate was significantly higher in patients with the SLC31A1 rs10981694 C allele compared with the rs10981694 A/A genotype (91.7% vs. 65.0%, P = 0.018). The 5-year disease-free survival rate was significantly higher in patients with the SLC31A1 rs10981694 C allele compared with the rs10981694 A/A genotype (79.2% vs. 55.0%, P = 0.043). In addition, univariate and multivariate analyses showed the SLC31A1 rs10981694 A > C polymorphism to be a significant prognostic factor affecting 5-year overall survival after neoadjuvant CRT. However, the overall and disease-free survival rates after surgery did not differ significantly among the ATP7B rs9535828 genotypes. In conclusion, only the SLC31A1 rs10981694 A/A genotype was an independent predictor of a poorer 5-year overall survival. Therefore, in neoadjuvant CRT for ESCC patients, the effect of platinum was affected by the SLC31A1 rs10981694 A > C polymorphism. The presence of this polymorphism should be considered when devising neoadjuvant CRT regimens or treatment strategies for ESCC.

186 Young Scholar Presentation: Immunometabolism during periods of negative nutrient balance or heat stress is altered by dietary methyl donor supply in dairy cows

Our research examined the effects of enhancing methyl donor supply on immunometabolism during periods of negative nutrient balance (NNB) or heat stress (HS). The first experiment examined the effects of post-ruminal choline supply during NNB on production and pathways of 1-carbon metabolism. Ten primiparous rumen-cannulated cows (158±24 DIM) were used in a replicated 5×5 Latin square design with 4d treatment periods and 10d of recovery. Treatments were unrestricted intake with abomasal infusion of water, restricted intake (R; 60% of net energy for lactation requirements) with abomasal infusion of water or R plus abomasal infusion of 6.25, 12.5, or 25 g/d choline ion. Liver tissue was collected at the end of each treatment period. Enhancing choline supply increased milk yields, but decreased liver triacylglycerol. Activity of betaine homocysteine methyltransferase increased with choline, while methionine synthase tended to increase, and cystathionine β-synthase was decreased. These changes were associated with increased liver and plasma Met. Overall, enhanced supply of choline during NNB increases flux through the Met cycle to regenerate Met and reduce liver triacylglycerol. The second experiment examined the effects of rumen-protected Met (RPM) during HS on mTOR (mechanistic target of rapamycin)-related signaling proteins in the mammary gland. Thirty-two multiparous cows (184±59 DIM) were assigned to an environmental treatment, and a dietary treatment [TMR with RPM (0.105% DM) or without (CON)] in a crossover design. There were 2 periods with 2 phases per period. In phase 1 (9d), all cows were in thermoneutral conditions (TN) and fed ad libitum. During phase 2 (9d), group 1 (n=16) was exposed to HS using electric heat blankets while group 2 (n=16) remained in TN but were pair-fed to HS counterparts. After a washout period (21d), the study was repeated (period 2), with environmental treatments being inverted and dietary treatments remaining the same. Mammary tissue was collected at the end of phase 2. Abundance of phosphorylated mTOR was greater with RPM and tended to be greater with HS. Control cows had a greater decrease in milk protein (%) during phase 2 (difference from phase 1) compared with RPM cows, suggesting that RPM supplementation during HS may support greater milk protein synthesis via mTOR activation. The third experiment investigated the effects of RPM during HS on the response of mammary gland explants to lipopolysaccharide (LPS). Twenty-five mg of tissue obtained from cows in the second experiment was incubated with 0 or 3 μg/mL of LPS for 2h. Incubation with LPS increased abundance of genes associated with inflammation, while HS decreased genes associated with antioxidant responses. Expression of NFKB1was greater in LPS-treated explants from non-HS compared with HS cows. These data indicate that HS reduced immune and antioxidant responses while RPM did not attenuate the inflammatory response induced by LPS in vitro. Overall, data indicated a beneficial effect of choline during NNB and Met during HS on immunometabolism in dairy cows.

Does the Addition of Abiraterone to Castration Affect the Reduction in Bone Mineral Density?

BACKGROUND/AIM

The in vivo effect of abiraterone on bone mineral density (BMD) in addition to androgen deprivation therapy was examined using a murine model.

MATERIALS AND METHODS

The mice were separated into the following groups: control, abiraterone, castration, and castration+abiraterone. The percentage change in the ratio of bone to tissue volume (BV/TV), number of osteoblasts and osteoclasts, and the serum level of bone markers were compared on day 21.

RESULTS

The BV/TV ratio of the abiraterone, castration, and castration+abiraterone groups was lower than that of the control group. However, the change in the BV/TV ratio in the castration+abiraterone group was not significantly different from that in the castration group. There was no significant difference in the serum TRAP5b level and the number of osteoclasts and osteoblasts between the castration+abiraterone and the castration groups.

CONCLUSION

The addition of abiraterone to castration did not affect BMD in the murine model.

Mitochondrial connexin43 affects arrhythmogenesis with modulation of mitochondrial KATP channels

Introduction

Connexin43 (Cx43) forms gap junction channels in ventricular muscle and also exits in the inner mitochondrial membrane (mCx43). We have previously reported that carbenoxolone, a blocker of Cx43, increased the occurrence of arrhythmias with modulation of mitochondrial KATP channels (mKATP).

Purpose

To examine how mCx43 and mKATP affect arrhythmogenesis, using cardiac-specific Cx43-deficient (Cx43−/−) mice.

Methods

To generate cardiac-specific Cx43−/− mice, Cx43flox/flox mice were crossed with α-myosin heavy chain (Myh6)-cre+/− mice. The resulting offspring, Cx43flox/flox/ Myh6-cre+/− mice (Cx43−/− mice) and their littermates (Cx43+/+ mice), were used. Trabeculae were dissected from right ventricles of mouse hearts (length ∼0.9 mm, width ∼200 μm, thickness ∼80 μm). Force was measured with a strain gauge, and intracellular Ca2+ (Cai) with fura-2 and a CCD camera (22°C). To assess arrhythmogenesis, the minimal extracellular Ca2+ concentration (Caomin), at which arrhythmias were induced by electrical stimulation (0.3-s stimulus intervals, 100 nM isoproterenol), was determined in mouse trabeculae. Using isolated single ventricular myocytes, mitochondrial membrane potential (ΔΨm) was estimated with tetramethylrhodamine methylester (TMRM) fluorescence, ROS production was estimated with 2',7'-dichlorofluorescein (DCF) fluorescence, and Ca2+ spark frequency was measured with fluo-4 and confocal microscopy. To investigate the roles of mKATP, 0.1 mM diazoxide, a mKATP channel opener, and 0.2 mM 5-hydroxydecanoic acid (5-HD), a mKATP channel inhibitor, were used.

Results

Most of Cx43−/− mice suddenly died within 8 weeks (p&lt;0.01). Cx43 was present in the inner mitochondrial membrane in Cx43+/+ mice, while it was not present in Cx43−/− mice. The resting and developed force and Cai transients by electrical stimulation (2-s stimulus intervals) showed no difference between Cx43−/− and Cx43+/+ mouse trabeculae (n=7). The Caomin in Cx43−/− mice was lower than that in Cx43+/+ mice (p&lt;0.01), and diazoxide increased the Caomin in Cx43−/− mice (p&lt;0.01), suggesting that arrhythmogenesis is increased in Cx43−/− mice and is decreased by diazoxide. Ca2+ spark frequency and DCF oxidation rate in Cx43−/− mice were higher than those in Cx43+/+ mice (p&lt;0.01). They were decreased by diazoxide and were increased by 5-HD (p&lt;0.01). TMRM fluorescence was decreased after electrical stimulation (1-s stimulus intervals) in Cx43−/− mice and was further decreased by 5-HD (p&lt;0.01), suggesting depolarization of ΔΨm in Cx43−/− mice. Such decrease in TMRM fluorescence in Cx43−/− mice was suppressed by diazoxide and did not occur in Cx43+/+ mice.

Conclusions

These results suggest that with modulation of mKATP, mCx43 plays important roles in ΔΨm determination, ROS production, and Ca2+ leak from the sarcoplasmic reticulum, thereby affecting arrhythmogenesis. Therefore, it is likely that mCx43 and mKATP could become a therapeutic target for controlling arrythmias.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant-in-Aid for Scientific Research (C) from Japan Society for the Promotion of Science

Eight-years trends and outcomes in TAVI performed in a high-volume center

Introduction

Since the first transcatheter aortic valve implantation (TAVI), remarkable changes in procedure features and patients' profile have been reported, making it a widespread treatment for severe aortic stenosis in all risk-class patients.

Purpose

To evaluate TAVI contemporary trends and outcomes in the last 8 years in a high-volume TAVI center.

Methods

Data of adult patients submitted to TAVI from April 2012 to April 2019 in a high-volume center were obtained from the Swiss TAVI registry, a prospective national multi-center database. Patients were divided according to implant period in two groups: 1) TAVI performed from 2012 to 2016, and 2) TAVI performed from 2017 to 2019.

Results

Over a 8-years period, a total of 1485 procedures were performed, increasing from 95 in 2012 to 320 in 2018 (p&lt;0.001). A remarkable modification in patients' profile and procedure characteristics can be seen in Table 1. Despite higher age and surgical risk, a significant decrease in 1-year mortality (6.8% vs. 3.2%; p&lt;0.001) was observed in the last 3 years. This difference was especially notable in the subgroup of high-risk patients (STS score ≥8), who presented a decrease in 30-days (5% vs. 3.3%; p=0.001) and 1-year mortality (13.1% vs. 4.9%; p&lt;0.001). In multivariate analysis, age (OR 1.05, 95% CI: 1.0–1.1), non-femoral access (OR 2.7, 95% CI: 1.2–6.0), and STS score (OR 1.07, 95% CI: 1.0–1.1) were independent predictors of in-hospital mortality, while male gender (OR 1.8, 95% CI: 1.0–3.2), chronic obstructive pulmonary disease (OR 2.1, 95% CI: 1.1–3.9), and STS score (OR 1.07, 95% CI: 1.01–1.14) were predictors of 1-year mortality.

Conclusion

Significant changes in patients' profile and procedure characteristics were observed in the last 3 years of TAVI experience. Even performed in elderly and high-risk patients, TAVI was associated with low early and 1-year mortality. The Swiss TAVI registry offers a unique opportunity to monitor trends and outcomes in patient submitted to TAVI.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): APT is a Ph.D. study and her scientific research is supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (Capes) - Finance Code 001.

Right ventricular longitudinal strain with CMR can more accurately estimate right ventricular functional reserve in rats with pulmonary arterial hypertension

Background

Right ventricular (RV) function is an important prognostic factor in patients with pulmonary arterial hypertension (PAH). Recently, CMR has become an attractive modality for follow up and providing prognosis in the patients, and strain has been used as a newer parameter to assess contractile properties of ventricle. It has not yet been established, however, whether RV strain with CMR can estimate RV functional reserve in the patients with PAH.

Purpose

We focused on CMR imaging of RV, investigating whether RV longitudinal strain can estimate RV functional reserve using a rat model with PAH.

Method

Rats were given a subcutaneous injection of 60 mg/kg monocrotaline (MCT-rats) or solvent (Ctr-rats). Four weeks after the injection, 25% of MCT-rats died due to RV failure. In the survivors of MCT- (n=19) and Ctr-rats (n=5), retrospective ECG-gated cine MR (16 phases/beat) was imaged with a 7T scanner. Subsequently, we measured RV pressure (RVP) via right internal jugular vein and dissected trabeculae (length = 1.45±0.07 mm, width = 334±27 μm, thickness = 114±6 μm) from RVs. We calculated weight ratio of RV free wall to left ventricle (LV) by RV/(LV+septum). Trabeculae were electrically stimulated with 2-s stimulus intervals, and force was measured using a silicon strain gauge (0.7 mM extracellular Ca2+, 24°C). To determine contractile properties of RV muscle, dF/dt was calculated. Using CMR imaging, we measured RV ejection fraction (RVEF) and RV longitudinal strain (RVLS). To modulate RVP, we intravenously injected 5 nmol endothelin-1 (ET-1) and again measured RVEF and RVLS.

Results

MCT-rats showed higher systolic RVP (62.5±16.6 vs. 25.9±1.86 mmHg, p&lt;0.01) and higher weight ratio of RV (0.60±0.03 vs. 0.28±0.02, p&lt;0.05). In CMR imaging, MCT-rats showed lower RVEF (36.1±11.2 vs. 64.8±8.4%, p&lt;0.001) and lower RVLS (−18±9 vs. −30±1%, p&lt;0.05). In trabeculae from RVs, MCT-rats showed lower developed force and lower dF/dt (p&lt;0.01). Correlation between RVLS and dF/dt was higher (n=20, r=0.53, p&lt;0.05) than that between RVEF and dF/dt (r=0.24). In addition, RVLS and dF/dt had already been decreased in 5 MCT-rats with relatively preserved RVEF (&gt;50%), suggesting that RVLS decreases earlier than RVEF in MCT-rats. Ten minutes after the injection of ET-1, RVP was increased from 49.4±7.9 to 57.9±6.4 mmHg in MCT-rats (n=6). In MCT-rats with preserved RVEF and decreased RVLS, the increase in RVP chiefly decreased RVEF while it did not change RVLS and RVEF in Ctr-rats, meaning that RV functional reserve had been decreased in MCT-rats. In trabeculae, developed force and dF/dt were increased after the addition of 0.1 μM ET-1 in MCT- (n=11, p&lt;0.01) and Ctr-rats (n=4, p&lt;0.01).

Conclusion

These results suggest that in rats with PAH, RVLS obtained from CMR can estimate RV functional reserve earlier and more accurately than RVEF. Therefore, RV strain with CMR may become an important parameter to assess RV functional reserve in patients with PAH.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant-in-Aid for Young Scientists