Fourfold Anisotropic Magnetoresistance of L1_{0} FePt Due to Relaxation Time Anisotropy

Experimental measurements show that the angular dependence of the anisotropic magnetoresistance (AMR) in L1_{0} ordered FePt epitaxial films on the current orientation and magnetization direction is a superposition of the corresponding dependences of twofold and fourfold symmetries. The twofold AMR exhibits a strong dependence on the current orientation, whereas the fourfold term only depends on the magnetization direction in the crystal and is independent of the current orientation. First-principles calculations reveal that the fourfold AMR arises from the relaxation time anisotropy due to the variation of the density of states near the Fermi energy under rotation of the magnetization. This relaxation time anisotropy is a universal property in ferromagnetic metals and determines other anisotropic physical properties that are observable in experiment.

715 REDUCING OVERTREATMENT OF TYPE 2 DIABETES IN OLDER PEOPLE LIVING IN CARE HOMES

Introduction

Older people in care homes living with frailty are less likely to benefit from tight glycaemic control in the management of type 2 diabetes with increased risk of adverse effects for example hypoglycaemia, falls and hospital admission. We wished to ascertain the scale of the problem and reduce overtreatment. We defined overtreatment based on American Diabetes Association guidelines as being on an agent that can cause hypoglycaemia and having an HBA1C of ≤53 mmol/mol or, an HbA1c 53–64 mmol/mol with either three or more co-morbidities.

Methods

In 2016, we audited the management of type 2 diabetes in older people discharged from LTHT to care homes. We discussed our concerns with diabetes and geriatric medicine colleagues across medical, nursing and pharmacy disciplines. We engaged the support of the citywide diabetes network which comprises secondary care colleagues, general practitioners and pharmacists. We presented the findings of our initial audit to colleagues within primary and secondary care through departmental meetings and citywide network meetings. We wrote a new guideline, specifically for frail older people that was disseminated citywide through these networks. We re-audited in 2020.

Results

In total, 113 cases were reviewed in 2016 and 105 cases in 2020. In 2020, only 6% (6 patients) were overtreated compared to 38% (43 patients) in 2016.

Conclusions

There has been a marked reduction in overtreatment which should result in less adverse events. We believe the reasons for success lie in wide engagement of relevant stakeholder groups around an issue that is important, large in scale and meaningful to both patient and clinician. There are potential cost savings from reducing medications and reducing harm.

Gompertz model in COVID-19 spreading simulation

The paper reports on application of the Gompertz model to describe the growth dynamics of COVID-19 cases during the first wave of the pandemic in different countries. Modeling has been performed for 23 countries: Australia, Austria, Belgium, Brazil, Great Britain, Germany, Denmark, Ireland, Spain, Italy, Canada, China, the Netherlands, Norway, Serbia, Turkey, France, Czech Republic, Switzerland, South Korea, USA, Mexico, and Japan. The model parameters are determined by regression analysis based on official World Health Organization data available for these countries. The comparison of the predictions given by the Gompertz model and the simple logistic model (i.e., Verhulst model) is performed allowing to conclude on the higher accuracy of the Gompertz model.

Anatomical dilation for the coronary sinus ostium in patients with pulmonary arterial hypertension and its impact to trigger the atrioventricular reentrant tachycardia: a case control study

Background

The incidence of atrioventricular reentrant tachycardia (AVNRT) in pulmonary arterial hypertension (PAH) patients is higher than the general population [1–3]. AVNRT had been reported with larger coronary sinus (CS) ostium in general population, while the mechanism and correlation between AVNRT and the CS ostium in PAH patients are poorly understood.

Purpose

We aim to investigate the impact of the CS ostium on AVNRT and find out its risk factors in PAH patients.

Methods

Of 102 pulmonary arterial hypertension (PAH) patients with catheter ablation of SVT, 10 patients confirmed AVNRT who underwent computed tomographic angiography (CTA) were enrolled as study group. The control group (PAH patients without SVT, n=20) were matched in a ratio of 2:1 based on gender and BMI. We measured maxium diameter of CS ostium in axial and LAO plane by CTA. All baseline characteristics and imaging materials were collected.

Results

PAH patients with AVNRT were older (45.9±14.8 vs. 32.1±7.6 years, P=0.025) and more likely to have larger CS ostium in LAO plane (18.6±3.3 vs. 14.8±4.0 mm, P=0.011) than those without AVNRT. The maximal diameter of CS ostium in LAO plane was an independent predictor for AVNRT in PAH patients (Odds ratio, 1.389; 95% confidence interval, 1.003–1.923; P=0.048). The cut-off value of CS ostium in LAO plane was 14.1mm (Area under curve = 0.79, P=0.012), and the sensitivity and specificity were 90% and 55%, respectively.

Conclusions

The larger CS ostium in LAO plane correlated with the higher prevalence of AVNRT in PAH patients with age. Patients with CS ostium larger than 14.1mm in LAO plane are more likely to develop AVNRT.

Funding Acknowledgement

Type of funding sources: None. Measurements and diagnosis value

Acute arterial events across all vascular territories in the FOURIER trial

Background

In the FOURIER (Further Cardiovascular Outcomes Research With PCSK9 Inhibition in Patients With Elevated Risk) trial, adding the PCSK9 inhibitor evolocumab to statin therapy reduced low-density lipoprotein cholesterol (LDL-C) and cardiovascular risk. Although atherosclerotic coronary, cerebrovascular, and peripheral vascular events share a related pathobiology, the effect of aggressive LDL-C lowering with PCSK9 inhibition on the risk of acute arterial events across all three vascular beds is not well-described.

Purpose

To assess the efficacy of evolocumab on acute arterial events in all vascular territories including coronary, cerebral, and peripheral vascular beds.

Methods

In the FOURIER trial, patients (n=27,564) with stable atherosclerotic cardiovascular disease and LDL-C ≥70 mg/dL on a statin were randomly assigned to evolocumab versus placebo and followed for a median of 2.2 years (1.8–2.5). Acute arterial events were defined as a composite of coronary (coronary heart disease [CHD] death, myocardial infarction [MI], or urgent coronary revascularization), cerebrovascular (ischemic stroke, transient ischemic attack [TIA], or urgent cerebral revascularization), or peripheral vascular (acute limb ischemia, major amputation, or urgent peripheral revascularization) events. Cox proportional-hazard models were used to assess the efficacy of evolocumab on these outcomes. Landmark and total event analyses were also done.

Results

Of the 2,210 first acute arterial events occurring during follow-up, 74% were coronary, 22% were cerebrovascular, and 4% were peripheral vascular. Evolocumab reduced the risk of a first acute arterial event by 19% (HR 0.81, 95% CI 0.74–0.88; P<0.001), with significant individual reductions in acute coronary (HR 0.83; 95% CI 0.75–0.91; P<0.001), acute cerebrovascular (HR 0.77; 95% CI 0.65–0.92; P=0.004), and acute peripheral vascular (HR 0.58; 95% CI 0.38–0.88; P=0.01) events (Figure, top). The magnitude of the risk reduction with evolocumab tended to increase over time, with a 16% reduction (HR 0.84; 95% CI 0.75–0.96) in the first year followed by a 24% reduction (HR 0.76; 95% CI 0.67–0.85) thereafter (Figure, bottom). There were 3,780 total acute arterial events (first plus recurrent), with a 22% reduction with evolocumab (incidence rate ratio [RR] 0.78; 95% CI 0.70–0.87). Evolocumab prevented 496 total acute arterial events as compared to 222 first events.

Conclusions

The addition of the PCSK9 inhibitor evolocumab to statin therapy reduced the risk of acute arterial events across all vascular territories with a robust effect over time. These findings indicate a pan-vascular impact of aggressive lipid-lowering therapy on these acute and clinically meaningful events.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): The FOURIER trial was supported by Amgen.

Mechanical circulatory support for refractory out-of-hospital cardiac arrest: a nationwide multicentre study

Background

Extracorporeal cardiopulmonary resuscitation (ECPR) has shown potential as a salvage therapy for patients with refractory out-of-hospital cardiac arrest (OHCA). Despite growing interest in and a growing body of literature on ECPR for refractory OHCA, robust evidence on patient eligibility is still lacking.

Purpose

To describe the survival, neurological outcome, and adherence to the national consensus with respect to use of ECPR for OHCA, and to identify factors associated with outcome.

Methods

Retrospective, observational cohort study of patients who underwent ECPR for OHCA at four cardiac arrest centres. Binary logistic regression and Kaplan-Meier survival curves were performed to assess association with 30-day mortality.

Results

A total of 259 patients receiving ECPR for OHCA between July 2011 and December 2020 were included in the study. Thirty-day survival was 26% and a good neurological outcome Cerebral Performance Category (CPC) 1–2 was observed in 94% of patients at discharge. Strict adherence to the national consensus showed a 30-day survival rate of 30%. Adding one or more of the following criteria to the national consensus: signs of life during cardiopulmonary resuscitation (CPR), pre-hospital low-flow <100 minutes, pH >6.8 and lactate <15 mmol/L increased the survival rate to 48%, but would exclude 58% of the survivors from the current cohort. Logistic regression identified initial presenting rhythm with asystole (RR 1.36, 95% CI 1.18–1.57), pulseless electrical activity (PEA) (RR 1.20, 95% CI 1.03–1.41), initial pH <6.8 (RR 1.28, 95% CI 1.12–1.46) and lactate levels >15 mmol/L (RR 1.16, 95% CI 1.16–1.53) as factors associated with increased risk of 30-day mortality. Patients presenting signs of life during CPR had threefold higher survival rate than patients without signs of life (45% versus 13%, p<0.001)

Conclusion

A high survival rate with a good neurological outcome was observed in this population of patients treated with ECPR for OHCA. Signs of life during CPR may aid the decision-making in the selection of appropriate candidates. Stringent patient selection for ECPR may produce higher survival rates but potentially withholds life-saving treatment in a significant proportion of survivors, why optimization of the selection criteria is still necessary.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): This work was supported by the Danish Heart Foundation [20-R142-A9498-22178]; and Health Research Foundation of Central Denmark Region [R64-A3178-B1349] Survival and adherence to consensusSigns of life during CPR

Characteristics and long-term ablation outcomes of supraventricular arrhythmias in hypertrophic cardiomyopathy: a 10-year, single-center experience

Background

A variety of supraventricular arrhythmias (SVAs) may occur in patients with hypertrophic cardiomyopathy (HCM). The characteristics and long-term ablation outcomes of different types of SVAs in HCM have not been comprehensively investigated.

Methods

We retrospectively enrolled 101 consecutive symptomatic HCM patients with suspected arrhythmia from May 2010 to October 2020. The clinical features and ablation outcomes of patients with SVAs were further analyzed.

Results

Seventy-eight patients had SVAs, consisting of 50 (64.1%) atrial fibrillation (AF), 16 (20.5%) atrial flutter (AFL), 15 (19.2%) atrioventricular reentrant tachycardia (AVRT), 11 (14.1%) atrial arrhythmia (AT), and 3 (3.8%) atrioventricular nodal reentrant tachycardia (AVNRT). Thirty-four patients underwent catheter ablation including 14 for AF, 9 for AVRT, 6 for AFL, 3 for AVNRT, 1 for both AF and AFL, and 1 for both AF and AVRT. They were followed up for a median (interquartile range) of 58.5 (82.9) months. There were no recurrences for patients with non-AF SVAs. For patients with AF, the 1- and 7-year AF-free survival were 87.5% and 49.5%, respectively. A ROC analysis revealed that a greater left ventricular end-diastolic dimension (LVEDD) was associated with higher recurrence of AF with an optimum cutoff value of 47mm (c-statistic = 0.91, p=0.011, sensitivity = 1.00, specificity = 0.82). In Kaplan-Meier analysis, patients with LVEDD ≥47mm had worse AF-free survival (log-rank p=0.014).

Conclusions

AF is the most common SVA in HCM, with AFL, AVRT, AT, and AVNRT ranking the second to the last according to the prevalence. The long-term catheter ablation outcome for non-AF SVAs in HCM is satisfying. A greater LVEDD predicts AF recurrence after catheter ablation in patients with HCM.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): National Natural Science Foundation of China Figure 1Figure 2

Idiopathic ventricular arrhythmias ablating from different subregions in the aortic sinus cusps: anatomic distribution, electrocardiography, and electrophysiology characteristics

Background

Previous studies had described the electrocardiographic or electrophysiological characteristics of ventricular arrhythmias (VAs) from 3 aortic sinus cusps (ASC) as a whole, while little is known about the differences among VAs ablated in different subregions of the ASC.

Objective

To investigate the distribution, specific precordial electrocardiographic sign, and bipolar electrogram characteristics of VAs ablated in different subregions of the ASC.

Methods

We divided the right coronary cusp (RCC) and the left coronary cusp (LCC) into 6 subregions and studied 51 idiopathic VAs ablated successfully in the ASC.

Results

Fifty-one VAs inhomogeneous distributed in the 6 subregions, which rarely located in the lateral RCC (L-RCC; 2%). The fractionated potential was dominant (39/51, 76%) in the three kinds of target electrograms. From the L-RCC to the lateral LCC (L-LCC), the percentage of fractionated potential gradually decreased from 100% to 59%. A precordial rebound notch in V3–4 or V4–5 had a sensitivity of 90.9%, a specificity of 85.0%, and a negative predictive value (NPV) of 97.1% to predict VAs ablating from the anterior RCC (A-RCC). A precordial rebound notch in V2–3 had a sensitivity of 50.0%, a specificity of 94.9%, and a NPV of 86.0% to predict VAs ablating from the L-LCC.

Conclusion

The targets of the ASC-VAs mainly distributed in the anterior ASC and the L-LCC. Fractionated potential is common among target bipolar electrograms especially in the anterolateral RCC. Precordial electrocardiographic rebound notch has a high predictive accuracy for identifying different subregions of the ASC-VAs.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

[Role of long noncoding RNA SNHG3 in regulating proliferation, migration and invasion of cervical cancer SiHa cells]

OBJECTIVE

To investigate the regulatory role of the long non-coding RNA (lncRNA) small nucleolar host gene 3 (SNHG3) in proliferation, migration and invasion of human cervical cancer cell line SiHa.

OBJECTIVE

Array data were retrieved from GEO database to analyze the expression levels of SNHG3 in cervical cancer and adjacent normal tissues. SiHa cells were transfected with a small interfering RNA (siRNA) targeting SNHG3, and the changes in the transcriptional levels of lncRNA SNHG3 and the epithelial-mesenchymal transition (EMT) markers N-cadherin, Snail, vimentin and E-cadherin were detected using real-time quantitative PCR; the protein expressions of N-cadherin, Snail, vimentin and E-cadherin were determined using Western blotting. Cell counting kit-8 (CCK8) assay was utilized to assess the proliferation capacity of the transfected cells. Wound healing assay and Transwell assay were performed to evaluate the transversal and longitudinal migration and invasion abilities of the cells.

OBJECTIVE

SNHG3 was over-expressed in cervical cancer tissues and SiHa cells. In SiHa cells, knocking down SNHG3 significantly inhibited the proliferation (P < 0.001), migration (P < 0.01) and invasion abilities (P < 0.001) of the cells, down-regulated the expression levels of N-cadherin, Snail and vimentin (P < 0.001) and up-regulated the expression of E-cadherin (P < 0.001).

OBJECTIVE

SNHG3 may promote the proliferation, migration and invasion of SiHa cells by activating the EMT signaling pathway.

Application of remote online learning in oral histopathology teaching in China

Background

The aim of this study was to investigate the application of remote learning and virtual microscopy in oral histopathology teaching, a unique experience in China. The oral histopathology teaching in Nanjing Medical University has been extraordinary.

Material and Methods

98 third-year dental students of Grade 2016 took oral histopathology theoretical course face-to-face in 2019 (Traditional group). The 94 participants of Grade 2017 took online oral histopathology course using digital methods(E-Learning platform and Virtual Simulation Experiment Teaching Center for Dentistry) in 2020. During the practical laboratory sessions, the students in both Traditional group and Online group observed the same glass slides for morphological learning. A questionnaire survey explored students' attitudes towards the remote online learning. Results: The mean Theory test scores of the Online group (80.93±12.15) were significantly higher than those of the Traditional group (73.65±8.46) (P < 0.01). The mean total scores of the Online group (82.94±10.76) were significantly higher than those of the Traditional group (77.25±7.55) (P < 0.01). The percentage of high total test score (test score > 85) of the Online group (54%) was also significantly higher than that of the Traditional group (15%) (P< 0.01). Furthermore, both remote learning and virtual microscopy courses were well accepted by students according to the questionnaire.

Conclusions

This study found that remote learning and virtual technology have a positive impact on oral histopathology. The findings reveal that the application of remote online learning has enhanced oral histopathology teaching in China.

Key words:Oral histopathology, dental undergraduate students, virtual microscopy, remote online learning, questionnaire.

DNA polymerase β may be involved in protecting human bronchial epithelial cells from the toxic effects induced by methyl tert-butyl ether exposure

Methyl tert-butyl ether (MTBE), a widely used gasoline additive and a ubiquitous environmental pollutant in many countries and regions, can cause various kinds of toxic effects on human health. However, the molecular mechanism underlying its toxic effects remains elusive. The present study aimed to explore the cytotoxicity, DNA damage and oxidative damage effects of MTBE on human bronchial epithelial cells (16HBE) and the possible role of DNA polymerase β (pol-β) in this process. RNA interference (RNAi) was used to obtain pol-β gene knocked-down cells (pol-β^-). CCK-8 assay was adopted to analyze the cell viability. Alkaline single-cell gel electrophoresis (SCGE) was performed to detect the DNA damage effects of MTBE. The enzyme activity of GSH-Px, SOD, CAT and the level of MDA were assessed. The data indicated that when treated with MTBE at the concentration exceeding 50 μmol/L and for the time exceeding 24 h, the pol-β^- exhibited significantly decreased cell viability and increased DNA damage effects, as compared to the control (P < 0.05). Furthermore, there was significant difference in the levels of GSH-pX, SOD, CAT and MDA between the pol-β^- and the control (P < 0.05). Our investigation suggests that MTBE can cause obvious cytotoxicity, DNA damage and oxidative damage effects on 16HBE cells. DNA polymerase β may be involved in protecting 16HBE cells from the toxic effects induced by MTBE exposure. These findings provide a novel insight into the molecular mechanism underlying the toxic effects of MTBE on human cells.

Comparative analysis of mouse and human preimplantation development following POU5F1 CRISPR/Cas9 targeting reveals interspecies differences

STUDY QUESTION

What is the role of POU class 5 homeobox 1 (POU5F1) in human preimplantation development and how does it compare with the mouse model?

SUMMARY ANSWER

POU5F1 is required for successful development of mouse and human embryos to the blastocyst stage as knockout embryos exhibited a significantly lower blastocyst formation rate, accompanied by lack of inner cell mass (ICM) formation.

WHAT IS KNOWN ALREADY

Clustered regularly interspaced short palindromic repeats-CRISPR associated genes (CRISPR-Cas9) has previously been used to examine the role of POU5F1 during human preimplantation development. The reported POU5F1-targeted blastocysts always retained POU5F1 expression in at least one cell, because of incomplete CRISPR-Cas9 editing. The question remains of whether the inability to obtain fully edited POU5F1-targeted blastocysts in human results from incomplete editing or the actual inability of these embryos to reach the blastocyst stage.

STUDY DESIGN, SIZE, DURATION

The efficiency of CRISPR-Cas9 to induce targeted gene mutations was first optimized in the mouse model. Two CRISPR-Cas9 delivery methods were compared in the B6D2F1 strain: S-phase injection (zygote stage) (n = 135) versus metaphase II-phase (M-phase) injection (oocyte stage) (n = 23). Four control groups were included: non-injected media-control zygotes (n = 43)/oocytes (n = 48); sham-injected zygotes (n = 45)/oocytes (n = 47); Cas9-protein injected zygotes (n = 23); and Cas9 protein and scrambled guide RNA (gRNA)-injected zygotes (n = 27). Immunofluorescence analysis was performed in Pou5f1-targeted zygotes (n = 37), media control zygotes (n = 19), and sham-injected zygotes (n = 15). To assess the capacity of Pou5f1-null embryos to develop further in vitro, additional groups of Pou5f1-targeted zygotes (n = 29) and media control zygotes (n = 30) were cultured to postimplantation stages (8.5 dpf). Aiming to identify differences in developmental capacity of Pou5f1-null embryos attributed to strain variation, zygotes from a second mouse strain-B6CBA (n = 52) were targeted. Overall, the optimized methodology was applied in human oocytes following IVM (metaphase II stage) (n = 101). The control group consisted of intracytoplasmically sperm injected (ICSI) IVM oocytes (n = 33). Immunofluorescence analysis was performed in human CRISPR-injected (n = 10) and media control (n = 9) human embryos.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A gRNA-Cas9 protein mixture targeting exon 2 of Pou5f1/POU5F1 was microinjected in mouse oocytes/zygotes or human IVM oocytes. Reconstructed embryos were cultured for 4 days (mouse) or 6.5 days (human) in sequential culture media. An additional group of mouse-targeted zygotes was cultured to postimplantation stages. Embryonic development was assessed daily, with detailed scoring at late blastocyst stage. Genomic editing was assessed by immunofluorescence analysis and next-generation sequencing.

MAIN RESULTS AND THE ROLE OF CHANCE

Genomic analysis in mouse revealed very high editing efficiencies with 95% of the S-Phase and 100% of the M-Phase embryos containing genetic modifications, of which 89.47% in the S-Phase and 84.21% in the M-Phase group were fully edited. The developmental capacity was significantly compromised as only 46.88% embryos in the S-Phase and 19.05% in the M-Phase group reached the blastocyst stage, compared to 86.36% in control M-Phase and 90.24% in control S-Phase groups, respectively. Immunofluorescence analysis confirmed the loss of Pou5f1 expression and downregulation of the primitive marker SRY-Box transcription factor (Sox17). Our experiments confirmed the requirement of Pou5f1 expression for blastocyst development in the second B6CBA strain. Altogether, our data obtained in mouse reveal that Pou5f1 expression is essential for development to the blastocyst stage. M-Phase injection in human IVM oocytes (n = 101) similarly resulted in 88.37% of the POU5F1-targeted embryos being successfully edited. The developmental capacity of generated embryos was compromised from the eight-cell stage onwards. Only 4.55% of the microinjected embryos reached the late blastocyst stage and the embryos exhibited complete absence of ICM and an irregular trophectoderm cell layer. Loss of POU5F1 expression resulted in absence of SOX17 expression, as in mouse. Interestingly, genetic mosaicism was eliminated in a subset of targeted human embryos (9 out of 38), three of which developed into blastocysts.

LIMITATIONS, REASONS FOR CAUTION

One of the major hurdles of CRISPR-Cas9 germline genome editing is the occurrence of mosaicism, which may complicate phenotypic analysis and interpretation of developmental behavior of the injected embryos. Furthermore, in this study, spare IVM human oocytes were used, which may not recapitulate the developmental behavior of in vivo matured oocytes.

WIDER IMPLICATIONS OF THE FINDINGS

Comparison of developmental competency following CRISPR-Cas-mediated gene targeting in mouse and human may be influenced by the selected mouse strain. Gene targeting by CRISPR-Cas9 is subject to variable targeting efficiencies. Therefore, striving to reduce mosaicism can provide novel molecular insights into mouse and human embryogenesis.

STUDY FUNDING/COMPETING INTEREST(S)

The research was funded by the Ghent University Hospital and Ghent University and supported by the FWO-Vlaanderen (Flemish fund for scientific research, Grant no. G051516N), and Hercules funding (FWO.HMZ.2016.00.02.01). The authors declare no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

CircRNA UBAP2 facilitates the progression of colorectal cancer by regulating miR-199a/VEGFA pathway

OBJECTIVE

The aim of this study is to explore the regulatory mechanism of circRNA UBAP2 (circUBAP2) in colorectal cancer (CRC).

PATIENTS AND METHODS

The expression levels of circUBAP2, miR-199a, and VEGFA in tissues and cell lines were detected by RT-qPCR. The cell proliferation was examined by CCK-8 and colony formation assays. The migration and invasion abilities were evaluated by wound healing and transwell assays, respectively. Bioinformatics analysis and Luciferase activity assay were applied to determine the interaction between genes.

RESULTS

The expression of circUBAP2 was upregulated in CRC tissues and cell lines, and depletion of circUBAP2 suppressed the cell proliferation, migration, and invasion of CRC. Furthermore, miR-199a inhibitor abrogated the suppressive effect of circUBAP2 knockdown on CRC progression. Vascular endothelial growth factor A (VEGFA) was identified as a downstream target gene of miR-199a, and overexpression of VEGFA rescued the tumor phenotypes attenuated by circUBAP2 knockdown or miR-199a overexpression.

CONCLUSIONS

Our findings demonstrated that circUBAP2 facilitated CRC progression by sponging miR-199a to upregulate VEGFA. These findings implied that circUBAP2 may be a potential therapeutic biomarker for CRC.

Germline nuclear transfer in mice may rescue poor embryo development associated with advanced maternal age and early embryo arrest

STUDY QUESTION

Can pronuclear transfer (PNT) or maternal spindle transfer (ST) be applied to overcome poor embryo development associated with advanced maternal age or early embryo arrest in a mouse model?

SUMMARY ANSWER

Both PNT and ST may have the potential to restore embryonic developmental potential in a mouse model of reproductive ageing and embryonic developmental arrest.

WHAT IS KNOWN ALREADY

Germline nuclear transfer (NT) techniques, such as PNT and ST, are currently being applied in humans to prevent the transmission of mitochondrial diseases. Yet, there is also growing interest in the translational use of NT for treating infertility and improving IVF outcomes. Nevertheless, direct scientific evidence to support such applications is currently lacking. Moreover, it remains unclear which infertility indications may benefit from these novel assisted reproductive technologies.

STUDY DESIGN, SIZE, DURATION

We applied two mouse models to investigate the potential of germline NT for overcoming infertility. Firstly, we used a model of female reproductive ageing (B6D2F1 mice, n = 155), with ages ranging from 6 to 8 weeks (young), 56 (aged) to 70 weeks (very-aged), corresponding to a maternal age of <30, ∼36 and ∼45 years in humans, respectively. Secondly, we used NZB/OlaHsd female mice (7-14 weeks, n = 107), as a model of early embryo arrest. This mouse strain exhibits a high degree of two-cell block. Metaphase II (MII) oocytes and zygotes were retrieved following superovulation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Ovarian reserve was assessed by histological analysis in the reproductive-aged mice. Mitochondrial membrane potential (△Ψm) was measured by JC-1 staining in MII oocytes, while spindle-chromosomal morphology was examined by confocal microscopy. Reciprocal ST and PNT were performed by transferring the meiotic spindle or pronuclei (PN) from unfertilised or fertilised oocytes (after ICSI) to enucleated oocytes or zygotes between aged or very-aged and young mice. Similarly, NT was also conducted between NZB/OlaHsd (embryo arrest) and B6D2F1 (non-arrest control) mice. Finally, the effect of cytoplasmic transfer (CT) was examined by injecting a small volume (∼5%) of cytoplasm from the oocytes/zygotes of young (B6D2F1) mice to the oocytes/zygotes of aged or very-aged mice or embryo-arrest mice. Overall, embryonic developmental rates of the reconstituted PNT (n = 572), ST (n = 633) and CT (n = 336) embryos were assessed to evaluate the efficiency of these techniques. Finally, chromosomal profiles of individual NT-generated blastocysts were evaluated using next generation sequencing.

MAIN RESULTS AND THE ROLE OF CHANCE

Compared to young mice, the ovarian reserve in aged and very-aged mice was severely diminished, reflected by a lower number of ovarian follicles and a reduced number of ovulated oocytes (P < 0.001). Furthermore, we reveal that the average △Ψm in both aged and very-aged mouse oocytes was significantly reduced compared to young mouse oocytes (P < 0.001). In contrast, the average △Ψm in ST-reconstructed oocytes (very-aged spindle and young cytoplast) was improved in comparison to very-aged mouse oocytes (P < 0.001). In addition, MII oocytes from aged and very-aged mice exhibited a higher rate of abnormalities in spindle assembly (P < 0.05), and significantly lower fertilisation (60.7% and 45.3%) and blastocyst formation rates (51.4% and 38.5%) following ICSI compared to young mouse oocytes (89.7% and 87.3%) (P < 0.001). Remarkably, PNT from zygotes obtained from aged or very-aged mice to young counterparts significantly improved blastocyst formation rates (74.6% and 69.2%, respectively) (P < 0.05). Similarly, both fertilisation and blastocyst rates were significantly increased after ST between aged and young mice followed by ICSI (P < 0.05). However, we observed no improvement in embryo development rates when performing ST from very-aged to young mouse oocytes following ICSI (P > 0.05). In the second series of experiments, we primarily confirmed that the majority (61.8%) of in vivo zygotes obtained from NZB/OlaHsd mice displayed two-cell block during in vitro culture, coinciding with a significantly reduced blastocyst formation rate compared to the B6D2F1 mice (13.5% vs. 90.7%; P < 0.001). Notably, following the transfer of PN from the embryo-arrest (NZB/OlaHsd) zygotes to enucleated non-arrest (B6D2F1) counterparts, most reconstructed zygotes developed beyond the two-cell stage, leading to a significantly increased blastocyst formation rate (89.7%) (P < 0.001). Similar findings were obtained after implementing ST between NZB/OlaHsd and B6D2F1 mice, followed by ICSI. Conversely, the use of CT did not improve embryo development in reproductive-age mice nor in the embryo-arrest mouse model (P > 0.05). Surprisingly, chromosomal analysis revealed that euploidy rates in PNT and ST blastocysts generated following the transfer of very-aged PN to young cytoplasts and very-aged spindles to young cytoplasts were comparable to ICSI controls (with young mouse oocytes). A high euploidy rate was also observed in the blastocysts obtained from either PNT or ST between young mice. Conversely, the transfer of young PN and young spindles into very-aged cytoplasts led to a higher rate of chromosomal abnormalities in both PNT and ST blastocysts.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The limited number of blastocysts analysed warrants careful interpretation. Furthermore, our observations should be cautiously extrapolated to humans given the inherent differences between mice and women in regards to various biological processes, including centrosome inheritance. The findings suggest that ST or PNT procedures may be able to avoid aneuploidies generated during embryo development, but they are not likely to correct aneuploidies already present in some aged MII oocytes.

WIDER IMPLICATIONS OF THE FINDINGS

To our knowledge, this is the first study to evaluate the potential of PNT and ST in the context of advanced maternal age and embryonic developmental arrest in a mouse model. Our data suggest that PNT, and to a lesser extent ST, may represent a novel reproductive strategy to restore embryo development for these indications.

STUDY FUNDING/COMPETING INTEREST(S)

M.T. is supported by grants from the China Scholarship Council (CSC) (Grant no. 201506160059) and the Special Research Fund from Ghent University (Bijzonder Onderzoeksfonds, BOF) (Grant no. 01SC2916 and no. 01SC9518). This research is also supported by the FWO-Vlaanderen (Flemish fund for scientific research, Grant no. G051017N, G051516N and G1507816N). The authors declare no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Downregulation of linc00961 contributes to promote proliferation and inhibit apoptosis of vascular smooth muscle cell by sponging miR-367 in patients with coronary heart disease

OBJECTIVE

Atherosclerosis is one of the most important risk factors for coronary heart disease (CHD), and growing evidence has shown that long non-coding RNAs (lncRNAs) can serve as prospective markers for atherosclerosis. In this study, we mainly focused on the potential roles of linc00961 in CHD patients.

PATIENTS AND METHODS

qRT-PCR was used to detect the expressions of linc00961 and miR-367 in CHD patients and ApoE-/-mice, and the correlations were analyzed. Then, HA-VAMC was respectively treated with 5 inflammatory factors and hypoxia conditions to explore the factors that affect linc00961 levels. Furthermore, the linc00961 overexpression lentivirus (LV-linc00961) and linc00961 downregulation lentivirus (LV-sh linc00961) were purchased and transfected into human vascular smooth muscle cells (VSMCs). CCK8 assay was carried out to measure the cell proliferation of VSMC, and the levels of Cyclin D1, Bcl-2, Bax, and cleaved caspase-3 were detected by RT-PCR and Western blot. Moreover, the Luciferase assay was performed to explore the binding site of linc00961 and miR-367. Finally, the miR-367 inhibitor was transfected into LV-sh linc00961 VSMCs to confirm the linc00961 functions via miR-367.

RESULTS

We found that linc00961 was significantly decreased in patients with CHD and ApoE-/-mice. Additionally, linc00961 was reduced in VSMCs at the conditions of hypoxia and C-reactive protein (CRP). Most importantly, the overexpression of linc00961 significantly inhibited the VSMCs proliferation, repressed the levels of Cyclin D1 and Bcl-2, and increased the levels of Bax and cleaved caspase-3. However, the downregulation of linc00961 promoted VSMCs proliferation, increased the levels of Cyclin D1 and Bcl-2, and repressed the levels of Bax and cleaved caspase-3. We also found that miR-367 was downregulated following the upregulation of linc00961, while it was upregulated following the downregulation of linc00961. The Luciferase gene reporter assay indicated that linc00961 could directly bind with miR-367 in VSMCs. Finally, we found that linc00961 could inhibit proliferation and promote apoptosis of VSMCs via binding with miR-367.

CONCLUSIONS

According to the results, our study revealed that linc00961 was significantly decreased in patients with CHD and ApoE-/-mice. Furthermore, our findings firstly uncovered that linc00961 was reduced by hypoxia and CRP in VSMCs. The downregulation of linc00961 contributed to promote proliferation and inhibit apoptosis of VSMCs by sponging miR-367 in CHD patients, which might provide a potential target for treating atherosclerosis.

Mesenchymal stem cells-originated exosomal microRNA-152 impairs proliferation, invasion and migration of thyroid carcinoma cells by interacting with DPP4

BACKGROUND

Thyroid carcinoma (THCA) is the most prevalent tumor in the endocrine system with an increasing incidence. Recent studies have underscored the function of microRNAs (miRNAs) in THCA. Nevertheless, knowledge regarding the effects of exosomal miRNAs in THCA is still limited. This report intended to probe the regulatory effects of exosomal miR-152 on THCA and the underlying mechanism.

METHODS

The expression profile of miR-152 was studied in clinical samples as well as B-CPAP and TPC-1 cells. Transwell, CCK-8, and flow cytometric assays were performed to investigate the roles of miR-152 on invasion, migration, proliferation, and apoptosis in B-CPAP and TPC-1 cells. The putative target of miR-152 was predicted using the bioinformatic analysis, and the targeting relationship was confirmed verified subsequently. Afterward, exosomes were isolated from bone marrow mesenchymal stem cells (BM-MSCs) and co-cultured with B-CPAP and TPC-1 cells to explore the function of exosomal miR-152 on THCA cells.

RESULTS

miR-152 was reduced in THCA tissues and cells. Restoration of miR-152 inhibited proliferation, invasion and migration of B-CPAP and TPC-1 cells, but promoted cell apoptosis. Dipeptidyl dipeptidase 4 (DPP4), a target of miR-152, was found to promote THCA cell invasion and migration. miR-152 ferried by BM-MSCs-derived exosomes repressed THCA cell invasion and migration, and pcDNA-DPP4 weakened the repression effect.

CONCLUSION

Exosomal miR-152 inhibited proliferation, migration and invasion of THCA cells by binding with DPP4, which may represent a novel target for the treatment of THCA.

Probabilistic topic modelling in food spoilage analysis: A case study with Atlantic salmon (Salmo salar)

Probabilistic topic modelling is frequently used in machine learning and statistical analysis for extracting latent information from complex datasets. Despite being closely associated with natural language processing and text mining, these methods possess several properties that make them particularly attractive in metabolomics applications where the applicability of traditional multivariate statistics tends to be limited. The aim of the study was thus to introduce probabilistic topic modelling - more specifically, Latent Dirichlet Allocation (LDA) - in a novel experimental context: volatilome-based (sea) food spoilage characterization. This was realized as a case study, focusing on modelling the spoilage of Atlantic salmon (Salmo salar) at 4 °C under different gaseous atmospheres (% CO₂/O₂/N₂): 0/0/100 (A), air (B), 60/0/40 (C) or 60/40/0 (D). First, an exploratory analysis was performed to optimize the model tunings and to consequently model salmon spoilage under 100% N₂ (A). Based on the obtained results, a systematic spoilage characterization protocol was established and used for identifying potential volatile spoilage indicators under all tested storage conditions. In conclusion, LDA could be used for extracting sets of underlying VOC profiles and identifying those signifying salmon spoilage, giving rise to an extensive discussion regarding the key points associated with model tuning and/or spoilage analysis. The identified compounds were well in accordance with a previously established approach based on partial least squares regression analysis (PLS). Overall, the outcomes of the study not only reflect the promising potential of LDA in spoilage characterization, but also provide several new insights into the development of data-driven methods for food quality analysis.

Serial measurement of biomarkers and the risk of stroke or systemic embolism and bleeding in patients with atrial fibrillation in ENGAGE AF-TIMI 48

Background

Patients with atrial fibrillation (AF) have progressive cardiac structural changes that may be manifest by biomarkers of myocardial injury and hemodynamic stress. Baseline values of hsTnT (high-sensitivity troponin T), and NT-proBNP (N-terminal pro-brain natriuretic peptide) are associated with stroke risk and GDF-15 (growth differentiation factor-15) is associated with bleeding risk in patients with AF. However, the variability of these biomarkers over time and their associations with stroke or systemic embolism events (S/SEE) and bleeding in patients with AF remain unclear.

Purpose

We examined whether patients with AF demonstrate detectable changes in these biomarkers over 12 months and whether such changes from baseline to 12 months are associated with the subsequent risk of S/SEE (hsTnT, NT-proBNP) and bleeding (GDF-15).

Methods

ENGAGE AF-TIMI 48 was a multinational randomized trial of the oral factor Xa inhibitor edoxaban in patients with atrial fibrillation and a CHADS2 score ≥2. We performed a nested prospective biomarker study in 6062 patients, analyzing hsTnT, NT-proBNP, and GDF-15 at baseline and 12 months. Event rates were estimated and displayed with annualized event rates after 12 months.

Results

Of 6062 patients, hsTnT was dynamic in 46.9% (≥2 ng/L change), NT-proBNP in 51.9% (≥200 pg/L change), GDF-15 in 45.6% (≥300 pg/L change) between baseline and 12 months. In addition, 7.7% in hsTnT shifted from low-&gt;high categories, 9.4% in NT-proBNP from low-&gt;high, 10.6% in GDF-15 from low-&gt;high over 12 months (Figure). Elevated hsTnT (≥14 ng/L) and NT-proBNP (≥900 pg/L) either at baseline or at 12 months were independently associated with higher rates of subsequent S/SEE, and elevated GDF-15 (≥1800 pg/L) either at baseline or at 12 months were independently associated with higher rates of subsequent bleeding (P&lt;0.001 for each). In a Cox regression model, the absolute changes in log2-transformed hsTnT and NT-proBNP were associated with increased risk of S/SEE (adj-HR, 1.75; 95% CI, 1.38–2.23; p&lt;0.001, and adj-HR, 1.31; 95% CI, 1.11–1.55; p=0.002, respectively) and log2-transformed GDF-15 with bleeding (adj-HR, 1.42; 95% CI, 1.04–1.92; p=0.025). Analyzed in a categorical manner (Figure), patients who increased hsTnT or NT-proBNP between baseline and 12 months or had high hsTnT or NT-proBNP at both timepoints were at higher risk for S/SEE (adj-HR 1.87 and 1.50 for hsTnT; adj-HR 1.80 and 2.59 for NT-proBNP, respectively). Patients with persistently elevated GDF-15 appeared to be at higher risk for bleeding (adj-HR,1.35) (Figure).

Conclusions

Serial assessment of hsTnT, NT-proBNP, and GDF-15 revealed a substantial proportion of patients with AF had dynamic values. Patients with either persistently elevated or dynamic values were at higher risk of adverse clinical outcomes. Those biomarkers may play a role in personalizing preventive strategies in patients with AF based on risk.

Change in biomarkers and event rate

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Daiichi Sankyo Pharma Development