Discordant responses of bone formation and absorption markers in Japanese infants with vitamin D deficiency: a comprehensive matched case-control study

Vitamin D deficiency during infancy has been associated with increased bone turnover rate and bone mineral loss. However, few studies have examined bone turnover markers (BTMs) for both bone formation and resorption in infants with vitamin D deficiency. Here, we analyzed serum concentrations of 25OHD, intact parathormone (iPTH), and BTMs including total alkaline phosphatase (ALP), tartrate-resistant acid phosphatase isoform 5b (TRACP-5b), and serum type I collagen N-telopeptide (NTx) as well as basic clinical characteristics of 456 infants (626 samples) aged less than 12 mo born at Saitama City Hospital, Japan (latitude 35.9° North) between January 2021 and December 2022. One hundred sixteen infants (147 samples) were classified as having vitamin D deficiency (25OHD < 12.0 ng/mL), and 340 infants (479 samples) had sufficient vitamin D levels (25OHD ≥ 12.0 ng/mL). In addition to 25OHD and ALP, both TRACP-5b and sNTx were measured in 331 infants (418 samples), while 90 infants (105 samples) had only TRACP-5b measured and 101 infants (103 samples) had only sNTx measured. Statistical comparison of 104 subjects each in the vitamin D deficiency and sufficiency groups after matching for the background characteristics revealed that the vitamin D deficiency group had significantly higher levels of ALP and iPTH compared with the sufficiency group (P = <.0001, .0012, respectively). However, no significant differences were found in TRACP-5b and NTx levels between the 2 groups (P = .19, .08, respectively). Our findings suggest discordant responses between bone formation and resorption markers in subclinical vitamin D deficiency during infancy.

GABAergic interneurons contribute to the fatal seizure phenotype of CLN2 disease mice

GABAergic interneuron deficits have been implicated in the epileptogenesis of multiple neurological diseases. While epileptic seizures are a key clinical hallmark of CLN2 disease, a childhood-onset neurodegenerative lysosomal storage disorder caused by a deficiency of tripeptidyl peptidase 1 (TPP1), the etiology of these seizures remains elusive. Given that Cln2 R207X/R207X mice display fatal spontaneous seizures and an early loss of several cortical interneuron populations, we hypothesized that those two events might be causally related. To address this hypothesis, we first generated an inducible transgenic mouse expressing lysosomal membrane-tethered TPP1 (TPP1LAMP1) on the Cln2 R207X/R207X genetic background to study the cell-autonomous effects of cell-type-specific TPP1 deficiency. We crossed the TPP1LAMP1 mice with Vgat-Cre mice to introduce interneuron-specific TPP1 deficiency. Vgat-Cre ; TPP1LAMP1 mice displayed storage material accumulation in several interneuron populations both in cortex and striatum, and increased susceptibility to die after PTZ-induced seizures. Secondly, to test the role of GABAergic interneuron activity in seizure progression, we selectively activated these cells in Cln2 R207X/R207X mice using Designer Receptor Exclusively Activated by Designer Drugs (DREADDs) in in Vgat-Cre : Cln2 R207X/R207X mice. EEG monitoring revealed that DREADD-mediated activation of interneurons via chronic deschloroclozapine administration accelerated the onset of spontaneous seizures and seizure-associated death in Vgat-Cre : Cln2 R207X/R207X mice, suggesting that modulating interneuron activity can exert influence over epileptiform abnormalities in CLN2 disease. Taken together, these results provide new mechanistic insights into the underlying etiology of seizures and premature death that characterize CLN2 disease.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Serum Creatinine-Cystatin C Based Screening of Sarcopenia in Community Dwelling Older Adults: A Cross-Sectional Analysis

OBJECTIVES

To compare the discriminative capabilities for the manifestation of sarcopenia or physical frailty between serum creatinine- and cystatin C-derived indices among community-dwelling older adults.

DESIGN

Cross-sectional study.

SETTING

Primary Care and Community.

PARTICIPANTS

We utilized a subset of data from the Frail Elderly in the Sasayama-Tamba Area (FESTA) study, which was initiated in 2015 to gather comprehensive information on various health-related parameters among community-dwelling older individuals (age ≥65 years).

MEASUREMENTS

Five serum creatinine-cystatin C based indices including the Sarcopenia Index, the serum creatinine/cystatin C ratio, the disparity between serum cystatin-C-based and creatinine-based estimated GFR, the total body muscle mass index (TBMM), and the prediction equation for skeletal muscle mass index (pSMI) were employed. Sarcopenia and physical frailty were identified based on the Asian Working Group for Sarcopenia criteria and the revised Japanese version of the Cardiovascular Health Study criteria, respectively. The receiver operating characteristic (ROC) and logistic regression analyses were performed to assess the discriminative abilities of these tools.

RESULTS

In the analysis of 954 participants, 52 (5.5%) were identified with sarcopenia and 35 (3.7%) with physical frailty. Regarding sarcopenia discrimination, TBMM and pSMI both exhibited area under the curve (AUC) values exceeding 0.8 for both men and women. Concerning the identification of physical frailty, AUC values ranged from 0.61 to 0.77 for males and 0.50 to 0.69 for females. In the multivariate logistic regression analyses, only TBMM and pSMI consistently displayed associations with sarcopenia, irrespective of sex (P<0.001, respectively). On the other hand, no consistent associations were observed between the indices and physical frailty.

CONCLUSIONS

This study provides a robust association of a serum creatinine- and cystatin C-derived indices, especially TBMM and pSMI, with sarcopenia among community-dwelling older adults. Conversely, the application of these indices for the screening of physical frailty has its constraints, necessitating further investigation.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Current treatment status of IgA nephropathy in Japan: a questionnaire survey

BACKGROUND

In 2020, the Committee of Clinical Practical Guideline for IgA Nephropathy (IgAN) revised the clinical practice guidelines. Herein, we conducted a questionnaire survey to assess the potential discrepancies between clinical practice guidelines and real-world practice in Japan.

METHODS

A web-based survey of members of the Japanese Society of Nephrology was conducted between November 15 and December 28, 2021.

RESULTS

A total of 217 members (internal physicians: 203, pediatricians: 14) responded to the questionnaire. Of these respondents, 94.0% answered that the clinical practice guidelines were referred to "always" or "often." Approximately 66.4% respondents answered that histological grade (H-Grade) derived from the "Clinical Guidelines for IgA nephropathy in Japan, 3rd version" and the "Oxford classification" were used for pathological classification. Moreover, 73.7% respondents answered that the risk grade (R-grade) derived from the "Clinical Guidelines for IgA nephropathy in Japan, 3rd version" was referred to for risk stratification. The prescription rate of renin-angiotensin system blockers increased based on urinary protein levels (> 1.0 g/day: 88.6%, 0.5-1.0 g/day: 71.0%, < 0.5 g/day: 25.0%). Similarly, the prescription rate of corticosteroids increased according to proteinuria levels (> 1.0 g/day: 77.8%, 0.5-1.0 g/day: 52.8%, < 0.5 g/day: 11.9%). The respondents emphasized on hematuria when using corticosteroids. In cases of hematuria, the indication rate for corticosteroids was higher than in those without hematuria, even if the urinary protein level was 1 g/gCr or less. Few severe infectious diseases or serious deterioration in glycemic control were reported during corticosteroid use.

CONCLUSION

Our questionnaire survey revealed real-world aspects of IgAN treatment in Japan.

An extremely energetic cosmic ray observed by a surface detector array

Cosmic rays are energetic charged particles from extraterrestrial sources, with the highest-energy events thought to come from extragalactic sources. Their arrival is infrequent, so detection requires instruments with large collecting areas. In this work, we report the detection of an extremely energetic particle recorded by the surface detector array of the Telescope Array experiment. We calculate the particle's energy as [Formula: see text] (~40 joules). Its arrival direction points back to a void in the large-scale structure of the Universe. Possible explanations include a large deflection by the foreground magnetic field, an unidentified source in the local extragalactic neighborhood, or an incomplete knowledge of particle physics.

Genomic characterization of thymic epithelial tumors in a real-world dataset

BACKGROUND

Thymic epithelial tumors (TETs) are rare neoplasms arising in the mediastinum, including thymic carcinomas and thymomas. Due to their rarity, little is known about the genomic profiles of TETs. Herein, we investigated the genomic characteristics of TETs evaluated in a large comprehensive genomic profiling database in a real-world setting.

METHODS

We included data from two different cohorts: Foundation Medicine Inc. (FMI) in the United States and the Center for Cancer Genomics and Advanced Therapeutics (C-CAT) in Japan. Samples profiled were examined for all classes of alterations in 253 genes targeted across all assays. Tumor mutational burden (TMB) and microsatellite instability (MSI) were also evaluated.

RESULTS

A total of 794 patients were collected in our study, including 722 cases from FMI and 72 cases from C-CAT. In the FMI data, CDKN2A (39.9%), TP53 (30.2%) and CDKN2B (24.6%) were frequently altered in thymic carcinoma, versus TP53 (7.8%), DNMT3A (6.8%), and CDKN2A (5.8%) in thymoma. TMB-high (≥10 mutations/Mb) and MSI were present in 7.0% and 2.3% of thymic carcinomas, and 1.6% and 0.3% of thymomas, respectively. Within C-CAT data, CDKN2A (38.5%), TP53 (36.5%) and CDKN2B (30.8%) were also frequently altered in thymic carcinoma, while alterations of TSC1, SETD2 and LTK (20.0% each) were found in thymoma.

CONCLUSIONS

To the best of our knowledge, this is the largest cohort in which genomic alterations, TMB and MSI status of TETs were investigated. Potential targets for treatment previously unbeknownst in TETs are identified in this study, entailing newfound opportunities to advance therapeutic development.

Measuring and maintaining organ perfusion in a patient with Takayasu's arteritis undergoing cardiac surgery

Takayasu's arteritis is a rare vasculitis affecting the aorta and its branches. Disease progression can result in arterial stenosis and subsequent organ dysfunction. Estimating organ perfusion by measuring the peripheral blood pressure can be challenging because it may be altered by arterial stenosis. We report the case of a 61-year-old woman with Takayasu's arteritis with aortic and mitral regurgitation who presented for aortic valve replacement and mitral valvuloplasty. Peripheral arterial pressure was considered a less reliable surrogate for organ perfusion because the patient had diminished blood flow in both the lower and upper extremities. In addition to the bilateral radial arterial pressure, the blood pressure in the ascending aorta was monitored to estimate the patient's organ perfusion pressure during cardiopulmonary bypass. The initial target blood pressure was determined based on the pre-operative baseline and modified by measurement of the aortic pressure. Cerebral oximetry using near-infrared spectroscopy and mixed venous saturation was monitored to estimate oxygen supply-demand balance, which helped evaluate cerebral perfusion and determine the transfusion threshold. The entire procedure was uneventful, and no organ dysfunction was observed postoperatively.

Gene therapy ameliorates spontaneous seizures associated with cortical neuron loss in a Cln2R207X mouse model

Although a disease-modifying therapy for classic late infantile neuronal ceroid lipofuscinosis (CLN2 disease) exists, poor understanding of cellular pathophysiology has hampered the development of more effective and persistent therapies. Here, we investigated the nature and progression of neurological and underlying neuropathological changes in Cln2R207X mice, which carry one of the most common pathogenic mutations in human patients but are yet to be fully characterized. Long-term electroencephalography recordings revealed progressive epileptiform abnormalities, including spontaneous seizures, providing a robust, quantifiable, and clinically relevant phenotype. These seizures were accompanied by the loss of multiple cortical neuron populations, including those stained for interneuron markers. Further histological analysis revealed early localized microglial activation months before neuron loss started in the thalamocortical system and spinal cord, which was accompanied by astrogliosis. This pathology was more pronounced and occurred in the cortex before the thalamus or spinal cord and differed markedly from the staging seen in mouse models of other forms of neuronal ceroid lipofuscinosis. Neonatal administration of adeno-associated virus serotype 9-mediated gene therapy ameliorated the seizure and gait phenotypes and prolonged the life span of Cln2R207X mice, attenuating most pathological changes. Our findings highlight the importance of clinically relevant outcome measures for judging preclinical efficacy of therapeutic interventions for CLN2 disease.

Safety Profile of the Concomitant Use of Atorvastatin and Cyclosporine in Renal Transplant Recipients

Cyclosporine (CyA) and atorvastatin (AT) are often administered concomitantly to treat dyslipidemia in renal transplant recipients. However, CyA greatly increases the plasma concentration of AT; therefore, concomitant use might increase the frequency of statin-induced adverse effects. The aim of this study was to investigate whether concomitant use of CyA and AT increases intolerance of the latter agent in Japanese renal transplantation recipients. We performed a retrospective cohort analysis of renal transplant recipients aged 18 years and older who had concomitantly received AT and CyA, or tacrolimus (Tac) therapy. We defined statin intolerance as a decrease in dose or discontinuation of AT due to adverse effects. We evaluated the incidence of statin intolerance in concomitant therapy with CyA for 100 days after the initial administration of AT in comparison with Tac. A total of 144 renal transplant recipients who received AT and CyA, or Tac between January 2013 and December 2019 were included. There was no statistical difference in the incidence of statin intolerance in both the CyA (1.8%; 1/57 patients) and Tac (3.4%; 3/87 patients) groups. Concomitant use of CyA and AT might not increase the incidence of statin intolerance in Japanese renal transplant recipients.

A mouse mutant deficient in both neuronal ceroid lipofuscinosis-associated proteins CLN3 and TPP1

Late-infantile neuronal ceroid lipofuscinosis (LINCL) and juvenile neuronal ceroid lipofuscinosis (JNCL) are inherited neurodegenerative diseases caused by mutations in the genes encoding lysosomal proteins tripeptidyl peptidase 1 (TPP1) and CLN3 protein, respectively. TPP1 is well-understood and, aided by animal models that accurately recapitulate the human disease, enzyme replacement therapy has been approved and other promising therapies are emerging. In contrast, there are no effective treatments for JNCL, partly because the function of the CLN3 protein remains unknown but also because animal models have attenuated disease and lack robust survival phenotypes. Mouse models for LINCL and JNCL, with mutations in Tpp1 and Cln3 respectively, have been thoroughly characterized but the phenotype of a double Cln3/Tpp1 mutant remains unknown. We created this double mutant and find that its phenotype is essentially indistinguishable from the single Tpp1^-/- mutant in terms of survival and brain pathology. Analysis of brain proteomic changes in the single Tpp1^-/- and double Cln3^-/- ;Tpp1^-/- mutants indicates largely overlapping sets of altered proteins and reinforces earlier studies that highlight GPNMB, LYZ2 and SERPINA3 as promising biomarker candidates in LINCL while several lysosomal proteins including SMPD1 and NPC1 appear to be altered in the Cln3^-/- animals. An unexpected finding was that Tpp1 heterozygosity significantly decreased lifespan of the Cln3^-/- mouse. The truncated survival of this mouse model makes it potentially useful in developing therapies for JNCL using survival as an endpoint. In addition, this model may also provide insights into CLN3 protein function and its potential functional interactions with TPP1. This article is protected by copyright. All rights reserved.

Utility of 5-aminolaevulinic acid fluorescence-guided endoscopic biopsy for malignant mesothelioma in a cat and dog

Malignant mesothelioma (MM) is uncommon in cats and dogs and can be challenging to diagnose. Adequate tissue sampling is required for superior diagnostic accuracy. Protoporphyrin IX, a metabolite of 5-aminolaevulinic acid (5-ALA), is a photosensitiser for photodynamic diagnosis (PDD). To the best of our knowledge, no study has reported the use of 5-ALA-PDD to detect MM in veterinary medicine. The present study describes the use of 5-ALA-PDD for MM diagnosis in a cat and dog, as well as the effectiveness of intracavitary chemotherapy. We evaluated the use of PDD with 5-ALA hydrochloride (5-ALA-PDD) in two cases of MM. A 12-year-old cat presented with a 1-month history of respiratory distress, and a 9-year-old dog presented with a 3-month history of mild abdominal distention. We endoscopically biopsied lesions in both the cases using 5-ALA-PDD. Histopathological examination revealed mesothelioma, and immunohistochemical staining was positive for calretinin. Both patients were treated with carboplatin. The cat died of respiratory failure. Although, the dog's condition improved 21 days after the first chemotherapeutic drug administration, the dog died on day 684 owing to cardiac-related issues. 5-ALA-PDD is thus, safe and feasible for the diagnosis of MM in veterinary medicine.

Early and post-treatment imaging findings in perineural spread: a pathway to diffuse muscle metastasis in recurrent bladder carcinoma

Perineural spread (PNS) from pelvic carcinoma has been regarded as a pathway to muscle and bone metastasis. However, few cases have been reported, especially in patients with bladder carcinoma. In the present report, we discuss a case of diffuse cancer involvement in the muscle 5 years after radical cystectomy for advanced bladder carcinoma. Careful observation of temporal changes on medical images confirmed PNS as the pathway to muscle metastasis (i.e., primary PNS). Our report presents early and post-treatment CT, MRI and FDG-PET/CT findings of PNS from the bladder carcinoma.

Advances in tooth agenesis and tooth regeneration

The lack of treatment options for congenital (0.1%) and partial (10%) tooth anomalies highlights the need to develop innovative strategies. Over two decades of dedicated research have led to breakthroughs in the treatment of congenital and acquired tooth loss. We revealed that by inactivating USAG-1, congenital tooth agenesis can be successfully ameliorated during early tooth development and that the inactivation promotes late-stage tooth morphogenesis in double knockout mice. Furthermore, Anti- USAG-1 antibody treatment in mice is effective in tooth regeneration and can be a breakthrough in treating tooth anomalies in humans. With approximately 0.1% of the population suffering from congenital tooth agenesis and 10% of children worldwide suffering from partial tooth loss, early diagnosis will improve outcomes and the quality of life of patients. Understanding the role of pathogenic USAG-1 variants, their interacting gene partners, and their protein functions will help develop critical biomarkers. Advances in next-generation sequencing, mass spectrometry, and imaging technologies will assist in developing companion and predictive biomarkers to help identify patients who will benefit from tooth regeneration.

Intraventricular pressure gradient: a novel colour M-mode echocardiographic-derived imaging modality to assess and predict the alterations following acute myocardial infarction

Funding Acknowledgements

Type of funding sources: None.

Background

Myocardial infarction (MI), caused by partial or total interruption of myocardial blood supply, is among the leading causes of morbidity and death. It can go silent (undetected), or it can be a catastrophic occurrence with severe hemodynamic alterations and abrupt death. Hence, immediate diagnosis or even prediction of these changes is really significant. Being the gold standard technique, echocardiography is typically adopted to identify heart dysfunctions. However, it exhibits a modest aptitude to foresee these variations. Intraventricular pressure gradient (IVPG) was introduced recently as a precise colour M-mode echocardiographic (CMME)-derived diastolic function imaging modality to assess the cardiac performance. Yet, its potential to assess and anticipate the alterations post-acute MI was not explored.

Purpose

The chief goal of this work is to study the efficacy of IVPG to measure and expect the alterations of rats’ cardiac functions at early stages of MI induced by variable LAD suture occlusion sites.

Methods

Fifty-five male SD rats were operated. Three different LAD occlusion sites were adopted to induce MI. In one group, LAD was occluded at the junction between LA and LV (MI-H, n=20). The middle and low ligation sites were more distal away from the base in two distinct groups (MI-M, n=15, and MI-L, n=10). The typical thoracotomy was accomplished in sham animals without occlusion of LAD (Sham, n=10). The sham and survived MI animals were checked using conventional echocardiography and CMME-derived IVPG on days 1, 7, 14, and 21 post MI induction. Afterwards, they were euthanized after transcatheter hemodynamics recording under the effect of anesthesia. The heart sections were stained to calculate the infarction size.

Results

The MI-H animals showed the lowest survival rate (35 % vs. 66.67, and 80 % in MI-M and MI-L groups; respectively). Moreover, they presented the most serious cardiac and hemodynamic alterations. The values of mid-to-apical, mid, and apical IVPG segments were significantly (P&lt; 0.001) declined in MI-M and MI-H groups compared to sham on days 7, 14, and 21. Likewise, they presented a meaningful reduction of the total IVPG on days 14, and 21. Contrarily, the basal IVPG was markedly (P&lt; 0.0001) elevated. Despite the echocardiographic changes were firstly recorded on day 14, the variations in the IVPG were recorded on day 7. The IVPG variables were significantly (P&lt; 0.0001) correlated with the echocardiographic, the hemodynamic (LVSP, LVDP, LVEDP, +dP/dtmax, -dP/dtmin, Tau) variables, and the infarction size. Moreover, all IVPG indices could significantly predict the cardiac and hemodynamic alterations occurred in varied degrees of severity. The Bland-Altman test confirmed the reproducibility of our IVPG measures.

Conclusion

CMME-derived IVPG is a novel and promising imaging modality with superior ability than conventional echocardiography to assess and predict the alterations encountered due to acute MI.

Incidence and clinical risk factors of Bednar's aphthae in Japanese newborns

BACKGROUND

The etiology of Bednar's aphthae remains unclear. Our aim was to investigate the incidence of, and factors associated with, Bednar's aphthae in a Japanese newborn cohort.

METHODS

A retrospective cross-sectional study was conducted on neonates discharged from the well-baby nursery at Saitama City Hospital, Japan. The principal investigator carefully examined each neonate's oral cavity, up to and including the pharynx, with a light-emitting diode (LED) headlight to determine the presence of Bednar's aphthae. Maternal and neonatal clinical characteristics were first compared between neonates with and those without Bednar's aphthae by univariate analysis. Variables with significant inter-group differences upon univariate analysis were entered into a multivariable logistic-regression model.

RESULTS

This study enrolled 1996 infants. We observed Bednar's aphthae in 9.3% of the Japanese newborn infants who were included. When restricted to infants who were born via vaginal delivery, 13.2% of them had aphthae. Multivariable logistic regression analysis identified vaginal delivery (odds ratio = 6.19, p < 0.0001) in Model 1, and vaginal delivery (odds ratio = 6.73, p < 0.0001) and birth weight (odds ratio = 0.9995, p = 0.034) in Model 2 as independent risk factors for the disease.

CONCLUSION

This is the first report of the prevalence of Bednar's aphthae among Japanese neonates. Vaginal delivery was identified as the strongest risk factor. Although confounding between mode of delivery and mechanical stimuli associated with sucking was not found in this study, the findings pave the way for a better understanding of the etiology of Bednar's aphthae.

Transmission of foreshock waves through Earth's bow shock

The Earth's magnetosphere and its bow shock, which is formed by the interaction of the supersonic solar wind with the terrestrial magnetic field, constitute a rich natural laboratory enabling in situ investigations of universal plasma processes. Under suitable interplanetary magnetic field conditions, a foreshock with intense wave activity forms upstream of the bow shock. So-called 30 s waves, named after their typical period at Earth, are the dominant wave mode in the foreshock and play an important role in modulating the shape of the shock front and affect particle reflection at the shock. These waves are also observed inside the magnetosphere and down to the Earth's surface, but how they are transmitted through the bow shock remains unknown. By combining state-of-the-art global numerical simulations and spacecraft observations, we demonstrate that the interaction of foreshock waves with the shock generates earthward-propagating, fast-mode waves, which reach the magnetosphere. These findings give crucial insight into the interaction of waves with collisionless shocks in general and their impact on the downstream medium.

Cross-species efficacy of enzyme replacement therapy for CLN1 disease in mice and sheep

CLN1 disease, also called infantile neuronal ceroid lipofuscinosis (NCL) or infantile Batten disease, is a fatal neurodegenerative lysosomal storage disorder resulting from mutations in the CLN1 gene encoding the soluble lysosomal enzyme palmitoyl-protein thioesterase 1 (PPT1). Therapies for CLN1 disease have proven challenging because of the aggressive disease course and the need to treat widespread areas of the brain and spinal cord. Indeed, gene therapy has proven less effective for CLN1 disease than for other similar lysosomal enzyme deficiencies. We therefore tested the efficacy of enzyme replacement therapy (ERT) by administering monthly infusions of recombinant human PPT1 (rhPPT1) to PPT1-deficient mice (Cln1-/-) and CLN1R151X sheep to assess how to potentially scale up for translation. In Cln1-/- mice, intracerebrovascular (i.c.v.) rhPPT1 delivery was the most effective route of administration, resulting in therapeutically relevant CNS levels of PPT1 activity. rhPPT1-treated mice had improved motor function, reduced disease-associated pathology, and diminished neuronal loss. In CLN1R151X sheep, i.c.v. infusions resulted in widespread rhPPT1 distribution and positive treatment effects measured by quantitative structural MRI and neuropathology. This study demonstrates the feasibility and therapeutic efficacy of i.c.v. rhPPT1 ERT. These findings represent a key step toward clinical testing of ERT in children with CLN1 disease and highlight the importance of a cross-species approach to developing a successful treatment strategy.

Live imaging of nitric oxide release in vascular endothelial cells in response to mechanical stimuli on an organ chip

Background

Nitric oxide (NO), released from vascular endothelial cells in response to mechanical stimuli, regulates cardiac contractility and are also involved in the prevention of the development of cardiac hypertrophy.

Purpose

To establish an experimental system for live observation of NO release in response to mechanical stimuli on an organ chip.

Methods

Organ chips, which we used for the development of a heart-on-a-chip in the previous study [1], were used.

We seeded 300,000 human umbilical vein endothelial cells on a stretchable elastic membrane coated with Matrigel of a chip channel. Shear stress was applied to the cells by increasing flow rate of a peristaltic pump connected to the chip channel (Figure 1A). Pressure stimulus was applied by hydrostatic pressure. Stretch stimulus was applied by suction to the side ports of a chip using an electric syringe pump (Figure 1B). Cells were stained with 10 μM 4,5-diaminofluorescein diacetate for fluorescent live NO imaging.

Results

Monolayers of the endothelial cells formed intercellular junctions confirmed by CD31 staining (Figure 1C, yellow). Apparent permeability, which was measured by Texas red dye (MW 3000), was maintained at a low level of ∼3x10–6 cm/s until day 30, suggested the formation of robust intercellular junction.

When the endothelial cells were subjected to a pressure stimulus of 60 mmHg for 60 s, NO release was observed that lasted for &gt;2 minutes (Figure 2A). A peak value of 1.46±1.08 (mean ± standard deviation) times the baseline was observed 271 s after the beginning of the pressure stimulus (n=251 cells). When the cells were subjected to a 1% stretch for 60 s, a peak value of 1.29±0.33 times the baseline was observed 105 s after the beginning of the stretch stimulus (Figure 2B). A shear stress of 0.01 dyn/cm2 hardly increased NO release (1.20±0.27 times the baseline, Figure 2C).

Conclusion

The system for live NO imaging in vascular endothelial cells in response to mechanical stimuli was established using organ-on-a-chip. The heart-on-a-chip with endothelial cells will be useful in elucidating the effects of mechanical stimulus such as hypertension on the contractile function and the remodeling of the heart.

Funding Acknowledgement

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

Functional analysis of thermo-sensitive TRPV1 in an aquatic vertebrate, masu salmon (Oncorhynchus masou ishikawae)

Transient receptor potential vanilloid 1 (TRPV1) is mainly expressed in nociceptive primary sensory neurons and acts as a sensor for heat and capsaicin. The functional properties of TRPV1 have been reported to vary among species and, in some cases, the species difference in its thermal sensitivity is likely to be associated with thermal habitat conditions. To clarify the functional properties and physiological roles of TRPV1 in aquatic vertebrates, we examined the temperature and chemical sensitivities of TRPV1 in masu salmon (Oncorhynchus masou ishikawae, Om) belonging to a family of salmonids that generally prefer cool environments. First, behavioral experiments were conducted using a video tracking system. Application of capsaicin, a TRPV1 agonist, induced locomotor activities in juvenile Om. Increasing the ambient temperature also elicited locomotor activity potentiated by capsaicin. RT-PCR revealed TRPV1 expression in gills as well as spinal cord. Next, electrophysiological analyses of OmTRPV1 were performed using a two-electrode voltage-clamp technique with a Xenopus oocyte expression system. Heat stimulation evoked an inward current in heterologously expressed OmTRPV1. In addition, capsaicin produced current responses in OmTRPV1-expressing oocytes, but higher concentrations were needed for its activation compared to the mammalian orthologues. These results indicate that Om senses environmental stimuli (heat and capsaicin) through the activation of TRPV1, and this channel may play important roles in avoiding environments disadvantageous for survival in aquatic vertebrates.

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Capsaicin evoked behavioral responses of Oncorhynchus masou ishikawae (Om).

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The behavioral response to heat was potentiated by capsaicin.

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Heterologously expressed OmTRPV1 was activated by heat and capsaicin.

Post COVID-19 condition of the Omicron variant of SARS-CoV-2

Objectives

To investigate the prevalence of post coronavirus disease (COVID-19) condition of the Omicron variant in comparison to other strains.

Study design

A single-center cross-sectional study.

Methods

Patients who recovered from Omicron COVID-19 infection (Omicron group) were interviewed via telephone, and patients infected with other strains (control group) were surveyed via a self-reporting questionnaire. Data on patients’ characteristics, information regarding the acute-phase COVID-19, as well as presence and duration of COVID-19-related symptoms were obtained. Post COVID-19 condition in this study was defined as a symptom that lasted for at least 2 months, within 3 months of COVID-19 onset. We investigated and compared the prevalence of post COVID-19 condition in both groups after performing propensity score matching.

Results

We conducted interviews for 53 out of 128 patients with Omicron and obtained 502 responses in the control group. After matching cases with controls, 18 patients from both groups had improved covariate balance of the factors: older adult, female sex, obesity, and vaccination status. There were no significant differences in the prevalence of each post COVID-19 condition between the two groups. The number of patients with at least one post COVID-19 condition in the Omicron and control groups were 1 (5.6%) and 10 (55.6%) (p = 0.003), respectively.

Conclusions

The prevalence of post Omicron COVID-19 conditions was less than that of the other strains. Further research with a larger sample size is needed to investigate the precise epidemiology of post COVID-19 condition of Omicron, and its impact on health-related quality of life and social productivity.

The cut-off values of vitamin D deficiency in early infancy

BACKGROUND

Several cut-off points for 25-hydroxyvitamin D (25(OH)D) levels have been proposed to determine vitamin D deficiency or insufficiency. However, the level for 25(OH)D deficiency in early infancy remains unclear. The serum 25(OH)D value at which parathyroid hormone level plateaus, called the "inflection point," is considered the most appropriate criterion for defining an adequate vitamin D status.

METHODS

This was a single-center retrospective study involving 305 1-month-old and 252 2-month-old Japanese infants. Nonlinear segmented regression analysis was performed based on the correlation between 25(OH)D and parathyroid hormone levels to determine vitamin D deficiency cut-off points.

RESULTS

Inflection points were 7.90 ng/mL for 1-month-old (95% confidence interval, 6.31-9.49) and 6.74 ng/mL for 2-month-old (95% confidence interval, 5.80-7.68) Japanese infants, which were lower than previously reported. Cut-off values were also lower in the high-body mass index (BMI) group than in the low-BMI group for both 1-month and 2-month-old infants.

CONCLUSION

These results imply the need for nutritional rickets prevention via policy recommendations in most full-term newborns in Japan. Although validation studies are required, these results can still be used to guide vitamin D insufficiency treatment options in early infancy.

Assemblies of 1,4-Bis(diarylamino)naphthalenes and Aromatic Amphiphiles: Highly Reducing Photoredox Catalysis in Water

Host–guest assemblies of a designed 1,4-bis(diarylamino)naphthalene and V-shaped aromatic amphiphiles consisting of two pentamethylbenzene moieties bridged by an m-phenylene unit bearing two hydrophilic side chains emerged as highly reducing photoredox catalysis systems in water. An efficient demethoxylative hydrogen transfer of Weinreb amides has been developed. The present supramolecular strategy permits facile tuning of visible-light photoredox catalysis in water.

P-153 Oocytes with narrow perivitelline space have poor fertilization and developmental potentials after ICSI

Study question

Do oocytes with narrow perivitelline space have poor clinical outcomes after ICSI?

Summary answer

After ICSI, oocytes with narrow perivitelline space have an increased degeneration rate and decreased rates of 2PN and embryo development.

What is known already

Several studies reported that oocytes with dysmorphologies, such as zona pellucida (ZP) abnormalities and cytoplasmic inclusions (vacuoles, smooth endoplasmic reticulum cluster, refractile bodies), have poor developmental potential in IVF/ICSI. In research on perivitelline space (PVS), many studies have focused on the PVS with fragmentation as well as large PVS. On the other hand, oocytes with narrow perivitelline space (narrow PVS oocytes) are considered to have an immature cytoplasm, but there are few reports on the relationship between narrow PVS oocytes and clinical outcomes. In this study, we retrospectively analyzed the effect of narrow PVS oocytes on ICSI outcomes.

Study design, size, duration

This retrospective single-center study analyzed 11149 MII oocytes that underwent ICSI between January 2018 and October 2021. We observed the PVS of MII oocytes during ICSI, and oocytes with sufficient PVS between the ZP and cytoplasm were determined to be non-narrow PVS oocytes. Oocytes without sufficient PVS from any angle (PVS was observed only around the first polar body) were defined as narrow PVS oocytes.

Participants/materials, setting, methods

After ICSI, oocytes were cultured in ONESTEP medium (NakaMedical, Tokyo, Japan). Embryos that developed into blastocysts were used for single vitrified-warmed blastocyst transfer (SVBT). We compared the rates of degeneration, 2PN, cleavage, blastocyst formation, good-grade (Gardner’s criteria ≥BB) blastocyst, top-grade blastocyst (Gardner’s criteria=AA), and clinical pregnancy (presence of a gestational sac) between oocytes with narrow and non-narrow PVS. Logistic regression analysis with consideration of patient age, BMI, and basal AMH was performed for each outcome.

Main results and the role of chance

Of the 11149 MII oocytes, 570 and 10579 were determined to be narrow and non-narrow PVS oocytes, respectively. Narrow PVS oocytes showed significantly higher degeneration rates (aOR: 1.52, 95% CI: 1.12–2.06, p&lt;0.01) and lower 2PN rates (aOR: 0.77, 95% CI: 0.64–0.93, p&lt;0.01) after ICSI compared to non-narrow PVS oocytes. Furthermore, rates of cleavage (aOR: 0.52, 95% CI: 0.31–0.87, p&lt;0.05), blastocyst formation (aOR: 0.56, 95% CI: 0.45–0.70, p&lt;0.01), good-grade blastocyst formation (aOR: 0.59, 95% CI: 0.46–0.76, p&lt;0.01), and top-grade blastocyst formation (aOR:0.625, 95% CI:0.45–0.86, p&lt;0.01), were significantly lower in the narrow PVS oocytes.

Of the blastocysts developed, 32 and 1439 blastocysts from narrow PVS oocytes and non-narrow PVS oocytes, respectively, were used for SVBT. The clinical pregnancy rate was not significantly different between blastocysts developed from narrow (aOR: 0.52, 95% CI, 0.22–1.22, p = 0.131) and non-narrow PVS oocytes. However, in blastocysts developed from narrow PVS oocytes, clinical pregnancy was confirmed only in top-grade blastocysts (58.8% [10/17]), and blastocysts of other grades did not result in pregnancy (0% [0/15]).

Limitations, reasons for caution

The limitation of this study is that it was a retrospective analysis conducted at a single IVF center. It is necessary to confirm the reproducibility at other facilities because the evaluation of PVS differs among embryologists and IVF centers. Therefore, a prospective multicenter study is needed.

Wider implications of the findings

We found that the narrow PVS oocytes showed poor outcomes after ICSI. While a good pregnancy rate could be expected if a top-grade blastocyst from such oocytes was obtained and transferred, the embryonic development rate of narrow PVS oocytes is low.

Trial registration number

Not applicable

P-215 Use of hyaluronan-based solution as an alternative to polyvinylpyrrolidone to improve blastulation in ICSI

Study question

This study aimed to analyze whether hyaluronan as an alternative to polyvinylpyrrolidone (PVP) for sperm immobilization, aspiration, and injection into the ooplasm improves ICSI outcomes.

Summary answer

The use of hyaluronan solution as an alternative to PVP improves the blastocyst formation rate and good quality blastocyst formation rate compared to PVP.

What is known already

The PVP solution facilitates ICSI procedures, such as sperm immobilization, aspiration, and injection into the ooplasm. However, it has been reported that injection of a small amount of PVP along with the sperm into the ooplasm negatively affects subsequent embryo development. Hyaluronan is a natural component of the extracellular matrix of the cumulus-oocyte complex. Balaban et al. (2003) reported that hyaluronan can replace PVP during ICSI procedures in the early embryo transfer cycle without adversely affecting pregnancy outcomes. This study analyzed whether using hyaluronan-based solution for the ICSI procedure would improves blastocyst development compared with ICSI using PVP.

Study design, size, duration

This retrospective study analyzed clinical medical reports at Takahashi Women’s Clinic, Japan. We included 4002 oocytes retrieved from 411 patients under 39 years of age who underwent ICSI using autologous oocytes between December 2019 and August 2021. Of the oocytes used for ICSI, 1909 underwent sperm aspiration and injection into the ooplasm with hyaluronan (Sperm Slow; Origio), and 2093 oocytes with 7% PVP (NakaMedical). We did not perform preimplantation genetic testing-aneuploidy for any cycles.

Participants/materials, setting, methods

We used PVP droplets for sperm selection under 400× magnification in both groups. In hyaluronan-ICSI, the selected sperm were transferred to a hyaluronan droplet and washed three times. The sperm was then aspirated with hyaluronan, and ICSI was performed. In PVP-ICSI, all procedures were performed using PVP. The ICSI and embryo transfer outcomes were compared between hyaluronan-ICSI and PVP-ICSI by logistic regression analysis considering patient age, BMI, and basal level of anti-mullerian hormone.

Main results and the role of chance

Normal fertilization rates were 74.3% (1556/2093) in PVP-ICSI and 75.5% (1442/1909) in hyaluronan-ICSI. There was no significant difference in the normal fertilization rate between PVP-ICSI and hyaluronan-ICSI groups (p = 0.437, aOR:1.06, 95% CI: 0.92–1.22). We cultured 1323 2PN embryos in PVP-ICSI and 1237 2PN embryos in hyaluronan-ICSI until the blastocyst stage. Blastocyst formation rates were 48.1% for PVP-ICSI and 52.3% for hyaluronan-ICSI, and this difference was statistically significant (aOR, 1.20; 95% CI: 1.02–1.40; p = 0.024). Moreover, the good grade (Gardner criteria ≧BB) blastocyst formation rates were significantly higher in the hyaluronan-ICSI group (36.9% and 41.0%, aOR: 1.21, 95% CI: 1.03–1.42, p = 0.022). During the study period, we performed 163 and 169 cryo-thawed blastocyst transfer cycles in PVP-ICSI and hyaluronan-ICSI, respectively. The clinical pregnancy rate (50.9% vs. 54.4%, aOR: 1.19, 95% CI: 0.77–1.83, p = 0.443) and miscarriage rate (19.3% vs. 13.0%, aOR: 0.66, 95% CI: 0.3–1.44, p = 0.295) after embryo transfer were not significantly different between PVP-ICSI and hyaluronan-ICSI.

Limitations, reasons for caution

The study was conducted at a single IVF center, and the oocytes included in this study were collected from patients aged &lt; 39 years. Embryo transfer result is based on ongoing pregnancy, while the live birth data for all pregnancies are not yet available.

Wider implications of the findings

Hyaluronan facilitates ICSI procedures such as sperm immobilization, aspiration, and injection. Moreover, the hyaluronan improves blastocyst development. The present study indicates that using hyaluronan as an alternative to PVP during the ICSI procedure is recommended.

Trial registration number

not applicable

P-395 Use of a granulocyte-macrophage colony-stimulating factor (GM-CSF)-containing medium for poor-grade blastocyst transfer increases the clinical pregnancy and live birth rates

Study question

Does the post-thaw use of a GM-CSF-containing medium improve blastocyst transfer outcomes in all blastocysts in a frozen-thawed embryo transfer cycle?

Summary answer

The use of a GM-CSF-containing medium at post-thawing especially improves the live birth (LB) rate of morphologically poor blastocysts in a frozen-thawed embryo transfer cycle.

What is known already

GM-CSF, a cytokine secreted by the epithelial cells of the female reproductive tract, plays an important role in embryonic development, implantation, and subsequent development in humans and animals. In humans, GM-CSF increases the blastocyst developmental rate and decreases the chances of miscarriage. Previously, we reported that the use of a GM-CSF-containing medium for blastocyst recovery culture after thawing improves the clinical pregnancy (CP) rate in a frozen-thawed blastocyst transfer cycle (ESHRE, 2019). However, it is unclear whether GM-CSF improves embryo transfer outcomes in all blastocysts. In addition, it is necessary to accumulate information regarding its effects on neonatal outcomes.

Study design, size, duration

We performed a retrospective observational study to compare two groups: a GM-CSF group (GM-CSF-containing medium; SAGE-1step GM-CSF, Cooper Surgical) and a control group (GM-CSF-free medium; ONE STEP Medium, NAKA Medical). We analyzed 566 blastocyst transfer cycles in patients aged 30–39 years who underwent frozen-thawed single embryo transfer at Takahashi Women’s Clinic (Japan) from February 2018 to February 2019. Chromosomal analysis was not performed.

Participants/materials, setting, methods

We used a control medium for blastocyst culture and a Cryotop safety kit for blastocyst vitrification. After thawing, we cultured blastocysts in a GM-CSF-containing medium or control medium for 3–5 h until transfer. Embryo transfer outcomes were compared. We performed the multivariate logistic regression analysis(MVRA) to adjust confounding bias. A subgroup analysis was also performed of morphological grade according to Gardner’s criteria (excellent: ≥AA, good: blastocysts containing B, poor: blastocysts containing C).

Main results and the role of chance

There were no difference in patient background between the two groups. The CP and LB rates in the GM-CSF group and control group were 54.3% vs. 42.6% and 42.9% vs. 31.1%. The MVRA adjusted by confounding factors(patient age, BMI, basal AMH, blastocyst grade, day of vitrification, number of previous failed ETs, and assisted hatching) demonstrated that CP (p = 0.0193; adjusted odds ratio [aOR], 1.55) and LB rate (p = 0.0080; aOR, 1.67) were significantly higher in GM-CSF group than that of control group. Moreover, the CP and LB rates of the GM-CSF group and control group were: excellent-blastocysts at 62.0% vs. 58.8% (p = 0.5955; OR, 1.14), 52.7% vs. 45.6% (p = 0.2466, aOR:1.33), good-blastocysts 52.1% vs. 37.6% (p = 0.0561; OR, 1.80), 38.0% vs. 26.6% (p = 0.1072; OR, 1.69), and poor-blastocysts 38.9% vs. 17.9% (p = 0.0115; OR, 2.92), 25.9% vs. 9.0% (p = 0.0164; OR, 3.56). A GM-CSF-containing medium significantly improved the CP and LB rates of poor-grade blastocysts. There were no significant differences between the GM-CSF group and control group in the male ratio (52.7％ vs. 51.0%, p = 0.8057), pregnancy duration (38.8±1.4 weeks vs. 38.5±1.8 weeks, p = 0.2558), cesarean section rate (38.2% vs. 40.8%, p = 0.6979), birth weight (3133±466g vs. 3037±437g, p = 0.1281), and congenital anomaly rate (0.91% vs. 2.04％, p = 0.6026).

Limitations, reasons for caution

This was a single-center, retrospective study. Chromosomal abnormalities in embryos were not considered; however, the LB rate among babies was analyzed. The basic chemical composition of the culture medium (salt concentration, glucose concentration, etc.) used in the control group was different from that of the GM-CSF-containing medium.

Wider implications of the findings

We found that the use of a GM-CSF-containing medium improved the clinical pregnancy and live birth rates of poor-grade blastocysts without affecting the babies. This may be an effective therapeutic strategy for some patients as it may allow for the effective use of poor-grade euploid blastocysts.

Trial registration number

not applicable

Collaborative Research Activities of the Arase and Van Allen Probes

This paper presents the highlights of joint observations of the inner magnetosphere by the Arase spacecraft, the Van Allen Probes spacecraft, and ground-based experiments integrated into spacecraft programs. The concurrent operation of the two missions in 2017-2019 facilitated the separation of the spatial and temporal structures of dynamic phenomena occurring in the inner magnetosphere. Because the orbital inclination angle of Arase is larger than that of Van Allen Probes, Arase collected observations at higher L -shells up to L ∼ 10 . After March 2017, similar variations in plasma and waves were detected by Van Allen Probes and Arase. We describe plasma wave observations at longitudinally separated locations in space and geomagnetically-conjugate locations in space and on the ground. The results of instrument intercalibrations between the two missions are also presented. Arase continued its normal operation after the scientific operation of Van Allen Probes completed in October 2019. The combined Van Allen Probes (2012-2019) and Arase (2017-present) observations will cover a full solar cycle. This will be the first comprehensive long-term observation of the inner magnetosphere and radiation belts.

Abstract 6389: A novel computational pipeline supported with in vivo vaccination models for identification and validation of neoantigens

Background: Personalized neoantigen-based therapies are being actively developed with several clinical trials currently ongoing. The standard methodology to identify patient specific neoantigens relies on computational algorithms for analyzing mutation, expression, and HLA profiles from patients’ NGS data. However, clinical reports have thus far showed that the number of actionable neoantigens was not as high as originally expected. One possible reason is due to a lack of appropriate prediction models, especially for immunogenicity, which is largely hindered by a scarcity of training data based on in vivo vaccination models. In addition, HLA allele status and/or impurity and heterogeneity in tumor samples are other factors affecting the selection efficiency.

Methods: We have developed a computational pipeline to identify neoantigens from patients’ WES and RNA-Seq data. Our HLA assessment not only determines HLA types but also detects HLA LOH events from WES and down-regulation of HLA gene expression from RNA-Seq taking into account tumor purity. The neoantigen candidates were ranked based on a presentation score calculated by a regression model optimized with publicly available immunopeptidome data. We tested our top-ranked neoantigen peptides by immunizing them into HLA-A02:01, A24:02, B07:02, and B35:01-transgenic mice and performed ELISPOT to determine positive or negative in vivo immune responses. Furthermore, we trained a neural network to define an immunogenicity score based on the results from the transgenic mouse experiments.

Results: We generated NGS data from over 100 clinical samples and analyzed the data using our computational pipeline. We observed a wide range in the tumor mutational burden and tumor purity of our samples, and HLA LOH was frequently observed. From 27 patient cases, 275 of HLA-A02:01-, A24:02-, B07:02-, or B35:01-predicted neoantigen epitopes were tested in transgenic mice and confirmed that the rate of positively reacted epitopes increased in a correlated manner to the presentation score, achieving 82% positive rate in top scored 35 epitopes and 47% in overall 275 epitopes. We further developed an immunogenicity prediction model and tested its performance in additional clinical samples. By integrating it into the selection criteria, we achieved higher positive rate than using the presentation score solely.

Conclusions: We have developed a robust computational pipeline to identify putatively actionable neoantigens from patients’ WES and RNA-Seq data. We detected frequent HLA LOH events indicating that this is a common mechanism of immune evasion. We also showed the feasibility of improving prediction algorithms using HLA-transgenic mice. Accurate prediction performance enables us to decrease the number of vaccine antigens to be immunized per patient, leading to a decrease in the manufacturing cost and complexity in quality control.

Citation Format: Kazushi Hiranuka, Keigo Takahashi, Dave Tang, Noriko Watanabe, Takashi Yamada, Yuji Mishima, Norihiro Fujinami, Manami Shimomura, Toshihiro Suzuki, Tetsuya Nakatsura, Norihiro Nakamura. A novel computational pipeline supported with in vivo vaccination models for identification and validation of neoantigens [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6389.

Na+/K+ ATPase α1 and β3 subunits are localized to the basolateral membrane of trophectoderm cells in human blastocysts

STUDY QUESTION

Is there a relation between specific Na+/K+ ATPase isoform expression and localization in human blastocysts and the developmental behavior of the embryo?

SUMMARY ANSWER

Na+/K+ ATPase α1, β1 and β3 are the main isoforms expressed in human blastocysts and no association was found between the expression level of their respective mRNAs and the rate of blastocyst expansion.

WHAT IS KNOWN ALREADY

In mouse embryos, Na+/K+ ATPase α1 and β1 are expressed in the basolateral membrane of trophectoderm (TE) cells and are believed to be involved in blastocoel formation (cavitation).

STUDY DESIGN, SIZE, DURATION

A total of 20 surplus embryos from 11 patients who underwent IVF and embryo transfer at a university hospital between 2009 and 2018 were analyzed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

After freezing and thawing Day 5 human blastocysts, their developmental behavior was observed for 24 h using time-lapse imaging, and the expression of Na+/K+ ATPase isoforms was examined using quantitative RT-PCR (RT-qPCR). The expressed isoforms were then localized in blastocysts using fluorescent immunostaining.

MAIN RESULTS AND THE ROLE OF CHANCE

RT-qPCR results demonstrated the expression of Na+/K+ ATPase α1, β1 and β3 isoforms in human blastocysts. Isoforms α1 and β3 were localized to the basolateral membrane of TE cells, and β1 was localized between TE cells. A high level of β3 mRNA expression correlated with easier hatching (P = 0.0261).

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The expression of mRNA and the localization of proteins of interest were verified, but we have not been able to perform functional analysis.

WIDER IMPLICATIONS OF THE FINDINGS

Of the various Na+/K+ ATPase isoforms, expression levels of the α1, β1 and β3 mRNAs were clearly higher than other isoforms in human blastocysts. Since α1 and β3 were localized to the basolateral membrane via fluorescent immunostaining, we believe that these subunits contribute to the dilation of the blastocoel. The β1 isoform is localized between TE cells and may be involved in tight junction formation, as previously reported in mouse embryos.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the JSPS KAKENHI (https://www.jsps.go.jp/english/index.html), grant number 17K11215. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The authors have no conflicts of interest.

Glial Dysfunction and Its Contribution to the Pathogenesis of the Neuronal Ceroid Lipofuscinoses

While significant efforts have been made in developing pre-clinical treatments for the neuronal ceroid lipofuscinoses (NCLs), many challenges still remain to bring children with NCLs a cure. Devising effective therapeutic strategies for the NCLs will require a better understanding of pathophysiology, but little is known about the mechanisms by which loss of lysosomal proteins causes such devastating neurodegeneration. Research into glial cells including astrocytes, microglia, and oligodendrocytes have revealed many of their critical functions in brain homeostasis and potential contributions to neurodegenerative diseases. Genetically modified mouse models have served as a useful platform to define the disease progression in the central nervous system across NCL subtypes, revealing a wide range of glial responses to disease. The emerging evidence of glial dysfunction questions the traditional “neuron-centric” view of NCLs, and would suggest that directly targeting glia in addition to neurons could lead to better therapeutic outcomes. This review summarizes the most up-to-date understanding of glial pathologies and their contribution to the pathogenesis of NCLs, and highlights some of the associated challenges that require further research.

The effects of vanilloid analogues structurally related to capsaicin on the transient receptor potential vanilloid 1 channel

Transient receptor potential vanilloid 1 (TRPV1) is known as a receptor of capsaicin, a spicy ingredient of chili peppers. It is also sensitive to a variety of pungent compounds and is involved in nociception. Here, we focused on the structural characteristics of capsaicin, and investigated whether vanillylmanderic acid (VMA), vanillic acid (VAcid), vanillyl alcohol (VAlc), vanillyl butyl ether (VBE), and vanillin, containing a vanillyl skeleton similar to capsaicin, affected the TRPV1 activities. For detection of TRPV1 activity, intracellular Ca²⁺ concentration ([Ca²⁺]_i) was measured in HEK 293 cells heterologously expressing mouse TRPV1 (mTRPV1-HEK) and in mouse sensory neurons. Except for vanillin, four vanilloid analogues dose-dependently increased [Ca²⁺]_i in mTRPV1-HEK. The solutions that dissolved VMA, VAcid and vanillin at high concentrations were acidic, whereas those of VAlc and VBE were neutral. Neutralized VAcid evoked [Ca²⁺]_i increases but neutralized VMA did not. Mutation of capsaicin-sensing sites diminished [Ca²⁺]_i responses to VAcid, VAlc and VBE. VAcid, VMA, and vanillin suppressed the activation of TRPV1 induced by capsaicin. VAcid and VMA also inhibited the acid-induced TRPV1 activation. In sensory neurons, VMA diminished TRPV1 activation by capsaicin or acids. The present data indicate that these structural characteristics of chemical compounds on TRPV1 may provide strategies for the development of novel analgesic drugs targeting nociceptive TRPV1.

Intraventricular pressure gradient: a promising tool to predict the post-infarction chronic congestive heart failure in rats

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction: Congestive heart failure (CHF), the main reason for morbidity and mortality, is considered a serious consequence of myocardial infarction (MI). The use of left ventricular end-diastolic pressure (LVEDP) as a chief indicator of CHF becomes limited because of the possible impairment of cardiac function and induced aortic valve damage during its recording. Echocardiography is the gold standard approach to diagnose structural myocardial dysfunction. However, its ability to predict chronic CHF following MI is still limited. Recently, intraventricular pressure gradient (IVPG) was presented as a non-invasive, highly sensitive preload-independent diastolic function parameter to assess cardiac function, especially during cardiomyopathy. However, there have not been any investigations demonstrating the feasibility of IVPG in the evaluation of post-infarction chronic CHF.

Purpose

This study aimed to investigate the utility of IVPG to assess the heart function in a rat model with chronic CHF following MI with evaluating its capacity to predict these changes.

Methods

Fifty male rats were included. MI was induced via ligation of the left anterior descending artery (LAD) at the level of the atrioventricular junction (MI animals, n = 35). Sham animals were subjected to the same left thoracotomy procedure without LAD ligation (Sham animals, n = 15). Transthoracic conventional echocardiography and colour M-mode echocardiography (CMME) for IVPG were performed in all animals 6 months post-surgery. The next day, animals were anesthetized, ventilated, and euthanized after the recording of hemodynamics. The heart weight, and lung and liver wet-to-dry weight ratios were recorded. J-tree cluster-analysis was performed based on ten echocardiographic variables indicative of CHF.

Results

Based on the cluster analysis, animals were joined into two clusters; CHF+ (n = 22) and named MI/HF+, and CHF- (n = 28) that was joined from sham (n = 15), and MI/HF- (n = 13). MI/HF+ presented the most severe anatomical and echocardiographic changes indicative of CHF with significant reduction of all IVPG indices and impairment of the hemodynamics. The IVPG indices were significantly (P&lt; 0.0001) correlated with the anatomical and echocardiographic findings, LVDP, LVEDP, HR, -dP/dtmin, and Tau. Meanwhile, LVSP was only significantly correlated with apical IVPG (R = 0.677, P = 0.022). dP/dtmax was significantly correlated with total IVPG, basal IVPG, and apical IVPG (R = 0.797, P = 0.017, R = 0.724, P = 0.003, and R = 0.652, P = 0.026 ; respectively). Moreover, total, basal, mid-to-apical, mid-, and apical IVPG were significant (P&lt; 0.0001) predictors of chronic CHF following MI.

Conclusion

Compared to the structural, and functional indices of conventional echocardiography, IVPG derived from CMME could provide a substantial non-invasive tool to diagnose and predict CHF after long-term MI.

Novel method of diastolic stress echocardiography during bottle-feeding for infants with congenital heart disease

Funding Acknowledgements

Type of funding sources: None.

Background

Recent studies have demonstrated the utility of diastolic stress echocardiography in evaluating diastolic dysfunction during exercise in adults. However, there have been no such reports in infants. This study determined whether measuring cardiac function using echocardiography during bottle feeding is a valid method of stress testing in infants with congenital heart disease.

Methods

The study population comprised 25 infants with congenital heart disease (Table 1). Echocardiographic measurements of the infants were taken during and after bottle feeding (Figure 1A). Active feeding (AF) was defined as the start of feeding during which the heart rate started increasing. End of feeding (EF) was defined as the time of completion of feeding during which the heart rate slowed down. The 25 infants were divided into two groups according to brain natriuretic peptide levels: less than 50 pg/ml (low group) and more than 50 pg/ml (high group). Cardiac function was compared between the groups using 2D speckle tracking analysis, and intraventricular pressure differences (IVPD) via color M-mode Doppler (Figures 1B and 1C) and 2D echocardiography. We compared the fractional change (FC%), defined as (AF and EF measurements)/EF measurements, between the two groups.

Results

Heart rate increased AF comparing with EF, significantly in both groups, the low group from 162 to 139 bpm; the high group from 152 to 140 bpm. The FC_IVPD was higher in the low group than in the high group (Figure.2). There were negative correlations between brain natriuretic peptide levels and the FC_IVPD (Figure 3). There were 4 cases were performed the intra-cardiac repair (ICR). In 2 cases, VSD and right ventricular outflow tract obstruction (RVOTO) velocity were increased during feeding. Indication of ICR, VSD case was aortic regurgitation with aortic cusp prolapse, TOF case was RVOTO. In VSD peak velocity in 2 cases did not increase during feeding (Table2). Indication of

ICR, two VSD cases were moderate left to right shunt, or pulmonary hypertension.

Conclusions

Our findings indicate that stress echocardiography during bottle-feeding might be a substitute for diastolic stress echocardiography in infants. The VSD or RVOT peak velocity, and FC% in IVP D and IVPG are sensitive markers for cardiac function in infants with congenital heart disease. Abstract Table1  Abstract Figure.

Assessment of anthracycline-induced cardiotoxicity in patients with childhood cancer survivor for long-term follow-up

Funding Acknowledgements

Type of funding sources: None.

Background

 Anthracycline cardiotoxicity is an important prognostic determinant in childhood cancer survivors (CCSs). That has been reported to improve with early therapeutic intervention, and because it is dose-dependent and progressive, early diagnosis and long-term follow-up are important. In adult survivors of cancer, the longitudinal strain (LS) is useful as a sensitive index of cardiac function. In childhood cancer survivors, strain abnormalities are also observed at both short-term and long-term follow-up. Global longitudinal strain (GLS) abnormalities are common during or early after chemotherapy, whereas changes in global circumferential strain (GCS) are more significant and consistent on long-term follow-up.

Purpose

 In this study, we aimed to conduct a cross-sectional study using strain analysis in childhood cancer survivors of a wide age range to clarify the mode of progression of anthracycline-induced cardiotoxicity and to identify useful indicators for long-term follow-up.

Methods

 In total, 116 patients (median age: 15.5 [range: 4.7-40.2] years) with childhood cancer who had passed at least 1 year after chemotherapy with anthracycline, and 116 control patients of similar age. Strain measurements were assessed for longitudinal strain (LS) and circumferential strain at the apical, papillary and basal levels using speckle tracking imaging. Estimated value at 5, 15, 25 and 35 years old were mathematically calculated.

Results

 Results were shown in tables and figures. Most of conventional echocardiographic parameters were not significantly different between CCCs and controls. LS, papillary CS and basal CS in CCCs decreased compared to normal controls at all age. The difference of estimated value between CCCs and normal controls in LS at all age were relatively constant. However, those in basal CS tended to increase with aging. Furthermore, basal CS in CCCs decreased with aging (r = 0.212, p &lt; 0.001) and the duration after completion of anthracycline treatment (r = -0.244, p &lt; 0.008).

Conclusions

 In childhood cancer survivors, strain analysis is a more sensitive indicators of cardiac function than conventional parameters. In addition, basal CS may decrease most markedly over time and could be useful indicator in long-term follow-up. Longitudinal studies should be conducted in the future to improve the accuracy of predicting anthracycline cardiotoxicity. These are new findings regarding the decline in cardiac function in childhood cancer survivors. Abstract Figure. Relationship between age and strains  Abstract Figure. Estimated values for each age group

Air pollution and airborne infection with mycobacterial bioaerosols: a potential attribution of soot

Atmospheric pollutants are hypothesized to enhance the viability of airborne microbes by preventing them from degradation processes, thereby enhancing their atmospheric survival. In this study, Mycobacterium smegmatis is used as a model airborne bacteria, and different amounts of soot particles are employed as model air pollutants. The toxic effects of soot on aerosolized M. smegmatis are first evaluated and excluded by introducing them separately into a chamber, being sampled on a filter, and then cultured and counted. Secondly, the bacteria-soot mixture is exposed to UV with different durations and then cultured for bacterial viability evaluations. The results show that under UV exposure, the survival rates of the low-, medium-, and high-soot groups are 1.1 (±0.8) %, 70.9 (±4.3) %, and 61.0 (±17.6) %, respectively. This evidence significantly enhanced survival rates by soot at all UV exposures, though the combinations of UV exposure and soot amounts revealed a changing pattern of survival rates. The possible influence by direct and indirect effects of UV-damaging mechanisms is proposed. This study indicates the soot-induced survival rate enhancements of M. smegmatis under UV stress conditions, representing the possible relations between air pollution and the extended pathogenic viability and, therefore, increased airborne infection probability.

Neuropathology of murine Sanfilippo D syndrome

Sanfilippo D syndrome (mucopolysaccharidosis type IIID) is a lysosomal storage disorder caused by the deficiency of N-acetylglucosamine-6-sulfatase (GNS). A mouse model was generated by constitutive knockout of the Gns gene. We studied affected mice and controls at 12, 24, 36, and 48 weeks of age for neuropathological markers of disease in the somatosensory cortex, primary motor cortex, ventral posterior nuclei of the thalamus, striatum, hippocampus, and lateral and medial entorhinal cortex. We found significantly increased immunostaining for glial fibrillary associated protein (GFAP), CD68 (a marker of activated microglia), and lysosomal-associated membrane protein-1 (LAMP-1) in Sanfilippo D mice compared to controls at 12 weeks of age in all brain regions. Intergroup differences were marked for GFAP and CD68 staining, with levels in Sanfilippo D mice consistently above controls at all age groups. Intergroup differences in LAMP-1 staining were more pronounced in 12- and 24-week age groups compared to 36- and 48-week groups, as control animals showed some LAMP-1 staining at later timepoints in some brain regions. We also evaluated the somatosensory cortex, medial entorhinal cortex, reticular nucleus of the thalamus, medial amygdala, and hippocampal hilus for subunit c of mitochondrial ATP synthase (SCMAS). We found a progressive accumulation of SCMAS in most brain regions of Sanfilippo D mice compared to controls by 24 weeks of age. Cataloging the regional neuropathology of Sanfilippo D mice may aid in understanding the disease pathogenesis and designing preclinical studies to test brain-directed treatments.

Development of a human heart-on-a-chip model using induced pluripotent stem cells, fibroblasts and endothelial cells

Background

The use of animal models in cardiovascular research is associated with two serious, intrinsic problems: inaccuracy in the extrapolation of data obtained from animals such as rodents due to different cardiac physiology and animal ethics.

Purpose

To develop an artificial human heart model for cardiovascular research using organ-on-a-chip technology and human cells

Methods

Organ chips made of silicone (polydimethylsiloxane) that have two microfluidic channels, a top channel and a bottom channel, separated by a 50-μm thick membrane with 7-μm pores hexagonally packed at 40-μm intervals (Figure 1), were used in this study.

We seeded 10,000 human umbilical vein endothelial cells on the membrane surface in the bottom channel to mimic the vasculature. Next, we seeded a mixture of 100,000 human-induced pluripotent stem cells (hiPSCs) and 50,000 human gingival fibroblasts on the membrane surface in the top channel (Figure 1). Human gingival fibroblasts facilitate cardiac differentiation of hiPSCs [1]. We performed the cardiac differentiation of hiPSCs using a previously described protocol [1]. Culture medium was perfused at a constant rate of 60 μl/h to maintain the culture.

Results

We observed spontaneous contraction of hiPSC-derived cardiomyocytes 20–26 days after the start of the differentiation protocol. Simultaneously, we conducted live intracellular calcium imaging using a fluorogenic calcium-sensitive dye, Cal-520 AM (5 μM in the culture medium). hiPSC-derived cardiomyocytes exhibited a periodic, coordinated pattern of calcium influx synchronised with their contraction under fluorescence microscopy (Figure 2A). Moreover, we found that the β-adrenergic agonist noradrenaline elevated the heart rate of hiPSC-derived cardiomyocytes on the organ chips in a dose-dependent manner (Figures 2A, B).

After observing the contraction and intracellular calcium influx of hiPSC-derived cardiomyocytes, we performed immunocytochemistry. Confocal microscopy indicated that the fluorescent signal obtained from anti-cardiac troponin T antibody staining in the top channel exhibited a typical striated pattern with 1.56±0.12-μm interval that reflected sarcomere structure (Figure 2C, yellow). Moreover, the fluorescent signal obtained from anti-CD31 antibody staining in the bottom channel exhibited a typical pattern at the boundary between cells, which is expected at the cell–cell junction of endothelial cells.

Conclusion

We developed a human heart-on-a-chip model that was confirmed by the functional response to noradrenaline and the histological evidence of sarcomere structure and vasculature, with a capability of live imaging. We expect that this model would be useful for examining the physiological function and for the pharmacological analysis of not only the normal heart but also the heart that reflects specific patient's pathophysiology using patient-derived hiPSCs.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Japan Society for the Promotion of Science Figure 1Figure 2

Cardiac function in fetal and infants born to mothers with gestational diabetes

Background

The intraventricular pressure differences (IVPD) IVPD using color M-mode is a specific marker in infants of mothers with gestational diabetes mellitus (GDM). (Circulation R 2019, 378–388).

Purpose

This study investigated the myocardial performance of fetuses in mothers with GDM under the new GDM definition.

Method

The study population comprised of 27 mothers with GDM and the fetus. Women with GDM were defined as those with a glucose metabolism abnormality that existed before or began during the current pregnancy and was diagnosed using OGTTs. The 5 mothers with type 1 or type 2 DM were receiving insulin before their pregnancy. Fetal echo measurements were performed about median gestational age 35 weeks. The primary outcomes were comparisons of the fetal myocardial performance of GDM with insulin administration and without administration using echocardiography with IVPD, and IVPG. The secondary outcome has investigated the relationships between echocardiography parameters, IVPD, and IVPG, and maternal factors. For all statistical analyses, P&lt;0.05 was considered significant.

Result

In the insulin group was higher RV output (Fig. 2A). Maternal max HbA1c was observed to have a positive correlation with fetal RV output, significantly (Fig. 2B). Maternal max fasting blood glucose was observed to have a negative correlation with the Total, Basal and Mid to apical IVPD, significantly, respectively. Serial change of LV Total IVPD from fetal to after birth shown in Slide. In both groups, LV Total IVPD was increasing from fetal and after birth significantly.

Conclusion

The mechanism associated with the favorable systolic and diastolic performances in IGDMs is suggested to involve metabolic adaptations in the heart. In diabetic mice, these adaptations seem to prevent the heart from failing during conditions of pressure overload, suggesting a restoration of the balance between glucose and fatty acid utilization is beneficial for cardiac function. In fetal LV and RV-IVPD might be interacted the mother's blood sugar control. These indexes can predict the sensitive fetal and infant's cardiac dysfunction for GDM.

Funding Acknowledgement

Type of funding sources: None.

The effect of a decrease in stretch-shortening cycle function after cycling on subsequent running

OBJECTIVES

Increased cardiorespiratory responses and changes in muscle activity and running kinematics occur in running after cycling compared with isolated running. Nevertheless, little is known about the causes of these changes. Cycling exercise decreases the stretch-shortening cycle (SSC) function, which can influence subsequent running. This study aimed to clarify whether the decrease in SSC function after cycling causes cardiorespiratory and biomechanical changes in subsequent running.

DESIGN

Cross-sectional laboratory study. Participants were divided into two groups based on SSC function: an SSC dec group (those with decreased SSC function after cycling) and an SSC non-dec group (those without decreased SSC function after cycling).

METHODS

Eighteen participants (10 triathletes and 8 runners) completed maximal aerobic tests for running and cycling. After these sessions, a submaximal run-cycle-run test was performed to compare between control run (no preceding cycle) and transition run (preceded by cycling). A jump test was administered before and after the submaximal cycling. SSC function was calculated as the ratio of the jump height to the time spent in contact with the ground (reactive strength index). Gas exchange measures, heart rate, and gait parameters were collected throughout the test.

RESULTS

Oxygen uptake and ventilation were increased by cycling in the SSC dec group but not in the SSC non-dec group. In both groups, there were no significant differences in the gait parameters between control and transition runs.

CONCLUSIONS

The decrease in SSC function after cycling would increase cardiorespiratory responses in subsequent running.