Quantitative determination of circulating L-cartinine and its derivates contributes to Heart failure diagnosis, etiology discrimination and clinical prognosis prediction

Background

Despite the latest progress in heart failure therapy, early diagnosis and clinical prognosis prediction are still critical issues nowadays. It has been proved that carnitines play an essential role in fatty acid metabolism. However, it is unclear about the changes and clinical effects of circulating carnitines in heart failure.

Objectives

This study was designed to clarify the alteration of serum carnitine and its derivates in heart failure patients, and to verify the impact of carnitines on heart failure etiology discrimination and mortality prediction.

Methods

A total of 161 heart failure patients (Dilated cardiomyopathy: DCM, n=98; ischemia cardiomyopathy: ICM, n=63) and control patients (n=48) were enrolled from Feb to Sep in 2017. Serum L-carnitines were quantitatively measured by liquid chromatography/ mass spectrometry. All patients underwent follow-up (mean 30.8 months). Multi-variable Cox survival was performed to verify the impact of carnitines on heart failure mortality prediction.

Results

A total of 27 different carnitine derivates were detected. Compared with control group, 26 types of carnitines were increased significantly in heart failure patients. Several circulating carnitines were independent biomarkers for heart failure even adjusted by multi-variable logistic analysis. We also found 7 carnitines were obviously increased in DCM group than those in ICM group. Isobutyryl-L-carnitine and stearoyl-L-carnitine were independently associated with higher probability of DCM than ICM. DCM prediction model established by adding carnitines (isobutyryl-L-carnitine and stearoyl-L-carnitine) to age, serum creatinine and left ventricular ejection fraction,had favorable discrimination (C-index = 0.832, P<0.01, Figure 1A and B) and calibration efficiency (Hosmer-Lemeshow χ2=7.376, P=0.497>0.05).

Meanwhile, a total of 43 mortality event occurred, 18 death (31.6%) in ICM group and 25 (27.2%) in DCM group. Independent clinical risk factors for the occurrence of mortality were serum creatinine >2mg/dl, left atrial diameter 0.55mm and N-terminal pro-B-type natriuretic peptide >4000 pg/ml. Using multi-variable COX survival analysis simultaneously adjusted by serum creatinine, left atrial diameter, NT-pro-BNP and age, oleoyl L-carnitine >300nmo/L (HR=2.364, 95% CI: 1.122–4.976, P=0.024) and isovaleryl-L-carnitine <100nmol/L (HR=2.108, 95% CI: 1.091–4.074, P=0.026) were also independently associated with higher mortality.

Conclusions

As one of critical participants in fatty acid metabolism, L-carnitines alteration not only differentiates DCM patients from ICM ones, but also independently predicts the risk of long-term mortality in heart failure patients.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Natural Science Foundation of China, Grant of Shanghai Municipal Commission of Health and Family Planning

Inhibition of CD44 attenuates pressure overload-induced cardiac and lung inflammation, fibrosis, and heart failure progression

Background

Inflammation contributes to heart failure (HF) development and progression. CD44 is a member of the hyaluronate receptor family of cell adhesion molecules, which regulates tissue inflammation and fibrosis through modulating macrophage and lymphocyte migration and homing in several diseases. Here we evaluated the role and cellular mechanism of CD44 in regulating transverse aortic constriction (TAC)-induced HF development and progression in mice.

Methods and results

C57/B6 background CD44 KO and wild type mice (6–8 weeks) were subjected to TAC to evaluate the effect of CD44 on the development of TAC-induced LV hypertrophy and cardiac dysfunction. Due to the rapid response to TAC, Balb/c mice (6–8 weeks) were used to determine the effect of CD44 on the progression of TAC-induced congestive heart failure. We found that CD44 expression is dramatically increased in left ventricular (LV) tissues obtained from HF patients and mice. While CD44 gene knockout (KO) has no detectable effect on cardiac structure and function under control conditions, CD44 KO mice were protected from TAC-induced LV inflammation, fibrosis, hypertrophy, dysfunction, and lung remodeling as compared with wild type mice. In addition, we found that inhibition of CD44 signaling with blocking antibodies (Abs) significantly attenuated the transition from LV failure to lung remodeling, and right ventricular hypertrophy in mice with existing HF.

Conclusions

These data identify an important role of CD44 in attenuating cardiac and lung inflammation, fibrosis, HF development, and HF progression, suggesting that inhibition of CD44 signaling may be useful in preventing and treating HF.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Chinese National Natural Science Foundation Grants and American Heart Association

SIRT5 deficiency enhances the proliferative and therapeutic capacities of adipose-derived mesenchymal stem cell via metabolic switching

Background

Mesenchymal stem/stromal cells (MSCs) render potential therapies for multiple ischemic diseases. However, in vitro expansion of MSCs before application leads to a metabolic switch from glycolysis to oxidative phosphorylation, drastically impairing their proliferative and therapeutic capacities.

Purpose

Here we aim to identify the role of SIRT5, a master metabolic regulator, in culture expansion of adipose-derived MSCs (ADMSCs).

Methods

SIRT5 deficiencyADMSCs was obtained from Sirt5−/− mice and their metabolic pattern and proliferation capacity were tested during in vitro expansion. Hind limb ischemic model was established to evaluated the therapeutic function of Sirt5−/−ADMSCs.

Results

SIRT5 protein level was upregulated in ADMCSs undergoing culture expansion. Sirt5−/−ADMSCs during in vitro expansion exhibited higher proliferation rate, delayed senescence and enhanced antioxidant capacity. SIRT5 deficiency induced hypersuccinylation of metabolic-related proteins, leading to attenuated mitochondrial respiration with elevated glycolysis and pentose phosphate pathway. Furthermore, lowering succinylation level by glycine treatment reversed the altered metabolism and enhanced proliferation of Sirt5−/−ADMSCs. In mice hind limb ischemic model, SIRT5−/−ADMSCs treatment achieved better blood flow recovery and angiogenesis compared to WT ADMSCs treatment.

Conclusion

We reveal that SIRT5 is a key regulator of ADMSCs undergoing in vitro culture. Ablation of SIRT5 leads to reversed metabolic pattern, enhanced proliferative capacity and improved therapeutic outcomes. Our data provide a potential target for enhancing MSC functional properties during bio-manufacturing in future MSC therapy. Such work may not only benefit MSC cell therapy, but could extent to a wide variety of other stem cells that share similar metabolic pattern.

Graphic Abstract

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Major Research Plan of the National Natural Science Foundation of China. National Science Fund for Distinguished Young Scholars.

Stillbirths in China: a nationwide survey

Objective

To estimate a stillbirth rate at 24 or more gestational weeks in 2015–2016 and to explore potentially preventable causes in China.

Design

A multi‐centre cross‐sectional study.

Setting

Ninety‐six hospitals distributed in 24 (of 34) provinces in China.

Population

A total of 75 132 births at 24 completed weeks of gestation or more.

Methods

COX Proportional Hazard Models were performed to examine risk factors for antepartum and intrapartum stillbirths. Population attributable risk percentage was calculated for major risk factors. Correspondence analysis was used to explore region‐specific risk factors for stillbirths.

Main outcome measures

Stillbirth rate and risk factors for stillbirth.

Results

A total of 75 132 births including 949 stillbirths were used for the final analysis, giving a weighted stillbirth rate of 13.2 per 1000 births (95% CI 7.9–18.5). Small for gestational age (SGA) and pre‐eclampsia/eclampsia increased antepartum stillbirths by 26.2% and 11.7%, respectively. Fetal anomalies increased antepartum and intrapartum stillbirths by 17.9% and 7.4%, respectively. Overall, 31.4% of all stillbirths were potentially preventable. Advanced maternal age, pre‐pregnant obesity, chronic hypertension and diabetes mellitus were important risk factors in East China; low education and SGA were major risk factors in Northwest, Southwest, Northeast and South China; and pre‐eclampsia/eclampsia and intrapartum complications were significant risk factors in Central China.

Conclusions

The prevalence of stillbirth was 13.2 per 1000 births in China in 2015–2016. Nearly one‐third of all stillbirths may be preventable. Strategies based on regional characteristics should be considered to reduce further the burden of stillbirths in China.

Tweetable abstract

The stillbirth rate was 13.2 per 1000 births in China in 2015–2016 and nearly one‐third of all stillbirths may be preventable.

The stillbirth rate was 13.2 per 1000 births in China in 2015–2016 and nearly one‐third of all stillbirths may be preventable.

[Screening for carriers of pathogenic genes for methylmalonic acidemia and Wilson's disease in neonates in Qingdao]

Objective: To investigate the carrier frequency of pathogenic genes for methylmalonic acidemia and Wilson's disease in neonates in Qingdao. Methods: In this cross-sectional study, using computer random sampling, 5 020 neonates from the neonatal screening center in Qingdao area from June 2016 to December 2018 were selected, and 5 012 of them were included in the carrier screening study.DNA was extracted from dried blood stain specimens used in the screening of newborns. Multiplex PCR combined with next generation sequencing were used for gene detection of MMACHC gene, MUT gene and ATP7B gene. The carrying rate of hotspots of each gene were calculated, and binomial distribution method was used to calculate 95% confidence interval of pathogenic gene carrying rate. Results: A total of 5 012 neonates completed the screening for carriers of disease-causing genes, of which 5 006 neonates completed the screening of two diseases and the remaining 6 neonates completed the screening of Wilson disease only.For ATP7B gene, the carrier frequency of the 12 hot spot mutations was 1.46% (73/5 012),and the 95% confidence interval was 1.16%-1.83%. For MMACHC gene and MUT gene, carrier frequency of 18 hot spot mutations was 2.50% (125/5 006) , and the 95% confidence interval was 2.10%-2.97%, among which cblC type accounted for 87.2% and the MUT pathogenic gene accounted for 12.8%. Conclusion: The carrier frequency of methylmalonic acidemia and Wilson's disease are both high in the neonatal population in Qingdao.

Towed Overhauser marine magnetometer for weak magnetic anomaly detection in severe ocean conditions

A towed Overhauser marine geomagnetic magnetometer used for weak magnetic anomaly detection in severe ocean conditions is studied to investigate means to reduce the negative effect of dynamic behavior and magnetic noise associated with ocean waves. For the dynamic effect, a continuous polarization workflow is proposed to enhance the free-induction-decay signal, and then, a multi-angle pickup coil and a self-tracking programmable amplifier are used to further reduce the adverse effect caused by uncontrollable changes in the towfish attitude on the signal quality. Furthermore, to achieve adaptive suppression of magnetic noise in different ocean conditions and areas, a modified adaptive Kalman algorithm is assessed. In addition, an optimized Overhauser sensor and a towfish were developed. Overall, the experimental results show that the sensor can effectively suppress the dynamic effect and magnetic noise. Regarding the magnetic sensitivity, uncertainty and range are 12 pT/Hz^1/2@1Hz and 0.21 nT and 20 000 nT-100 000 nT, respectively. Moreover, underwater testing was performed to verify the function and the detection of the magnetic anomaly.

[Progress of interruption of schistosomiasis transmission in Jiangsu Province]

Schistosomiasis was once heavily endemic in Jiangsu Province. Following the control efforts for several decades, schistosomiasis was almost eradicated in all endemic counties in Jiangsu Province in 1980, and transmission control was achieved in the province in 2011. According to the principle of "implementing the control measures with adaptation to local circumstances and guiding the control programs with classified interventions", an integrated strategy with emphasis on the management of both infectious sources and snails has been recently employed for schitsosomiasis control in Jiangsu Province. In addition, a sensitive and highly effective surveillance system has been built and the application of novel techniques and information construction has been intensified to effectively interrupt the transmission of schistosomiasis in the Province. Transmission interruption of schistosomiasis was achieved in all endemic counties in Jiangsu Province. The paper summarizes the endemic situation of schistosomiasis, progress of schistosomiasis control, and major schistosomiasis control measures implemented during the stage of transmission interruption in Jiangsu Province.

[How to make the intraocular pressure after glaucoma filtering surgery more controllable]

Glaucoma surgery is one of the main methods of glaucoma treatment. In recent years, glaucoma surgery has been greatly developed. Minimally invasive surgical procedures for glaucoma have emerged. Patients and surgeons have also increased their expectations of surgery. However, due to the limitation of surgical controllability, the prediction of postoperative efficacy is still not satisfactory. By analyzing the principles and limitations of the existing surgical procedures, the authors put forward the premise of the controllability of glaucoma extrafiltration surgery as that the intraoperative filtration excess can be restricted, so as to effectively avoid the early postoperative complications such as shallow anterior chamber, hypotony and strong inflammation. And within 1 month after surgery, through the filtration of the bubble and the removal of the adjustable suture, the ideal filtration state is gradually achieved. With the controllable maintenance of intraocular pressure at 1 month after surgery, it is possible to effectively predict the intraocular pressure level of 2 years or longer. (Chin J Ophthalmol, 2020, 56: 13-16).

Supervised Autonomous Electrosurgery via Biocompatible Near-Infrared Tissue Tracking Techniques

Autonomous robotic surgery systems aim to improve patient outcomes by leveraging the repeatability and consistency of automation and also reducing human induced errors. However, intraoperative autonomous soft tissue tracking and robot control still remains a challenge due to the lack of structure, and high deformability of such tissues. In this paper, we take advantage of biocompatible Near-Infrared (NIR) marking methods and develop a supervised autonomous 3D path planning, filtering, and control strategy for our Smart Tissue Autonomous Robot (STAR) to enable precise and consistent incisions on complex 3D soft tissues. Our experimental results on cadaver porcine tongue samples indicate that the proposed strategy reduces surface incision error and depth incision error by 40.03% and 51.5%, respectively, compared to a teleoperation strategy via da Vinci. Furthermore, compared to an autonomous path planning method with linear interpolation between the NIR markers, the proposed strategy reduces the incision depth error by 48.58% by taking advantage of 3D tissue surface information.

P6306Hyperlipidemia inhibits the protective effect of lisinopril after myocardial infarction via activation of dendritic cells

Background

In clinical situation, patients with myocardial infarction (MI) usually suffered from hyperlipidemia, hypertension, renal dysfunction or diabetes as well and the interaction of those risk factors may affect the effectiveness of ACEI. Dendritic cell (DC) is a potent central immunoregulator that orchestrates various types of inflammatory cells in innate and adoptive immunity. The role of DCs in the inflammation of cardiovascular disease is a hotspot of international research.

Purpose

To investigate the improvement of cardiac remodeling and inflammatory immune response after MI via ACEI regulating DCs and explore that whether the protective effect of ACEI is under the circumstance of hyperlipidemia.

Methods

In vivo, MI mice models were created via coronary artery ligation. We detected the survival and left ventricular function on day 7 after MI. Tissue samples of the myocardium, spleen, bone marrow and peripheral blood were obtained and assessed for Ang2 concentration, inflammatory cytokines and DCs expression via immunohistochemistry, ELISA, flow cytometry and western blot. In vitro, we treated DCs with ox-LDL+AngIIfor 48 hours simulating the internal environment of MI in ApoE−/− mice to explore the mechanism involved in the DCs maturation and inflammation.

Results

Under the circumstance of hyperlipidemia, the cardioprotective effect of ACEI is attenuated through regulating DCs maturation and inflammation after MI, including survival rate (Figure 1) and left ventricular function. The number of DCs in cardiac tissue were increased in MI mice with hyperlipidemia (Figure 2), when compared with the WT group. The expression of the maturity phenotype related molecules, such as CD83, on the DCs in spleen were also increased in the ApoE−/− mice. Then, the expressions of inflammatory cytokines, such as IL-6 and TNF-α. In vitro, it was found that the immune maturation and inflammation of DCs could be further induced by ox-LDL on the basis of AngIItreatment, as indicated by the upregulation of CD83 and CD86, the expressions of cytokines and chemokines. Furthermore, ox-LDL could activate the toll-like receptor 4 (TLR4)-myeloid differentiation factor 88 (MyD88) signaling pathway, promoting the phosphorylation of interleukin-1 receptor associated kinase (IRAK)-4 and the nuclear transferring of nuclear factor-kappaB (NF-κB).

Conclusion

We proved ACEI reduces the recruitment of DCs to the infarct, leading to a higher survival rate and improved function and remodeling through decreased inflammation resulting from immune response after MI. However, this effect was inhibited under the circumstance of hyperlipidemia. TLR4-MyD88 signaling pathway might be the possible molecular mechanism involved in the immune maturation and inflammation of DCs induced by ox-LDL on the basis of AngII.

Acknowledgement/Funding

the Youth fund of the National Natural Science Foundation of China, Grant 81600280

P6501Recurrent genetic aberrations in bicuspid aortic valve disease patients with isolated severe aortic regurgitation

Background

The etiology of bicuspid aortic valve disease (BAVD) is still unclear. Recent studies have demonstrated elevated prevalence of genetic defects in BAV patients with root phenotype, which includes aortic regurgitation and root-predominant dilatation.

Purpose

The present study intended to illustrate the feature of genetic defects among early-onset BAV patients with isolated severe aortic regurgitation.

Methods

From June 2015 to December 2017, whole exome sequencing was performed upon 27 BAVD patients with isolated severe aortic regurgitation under 45 years in our institution. Patients were categorized into right-left (R-L, n=16) and non-RL (n=11) cusp fusion types, and those with complex cardiac defects were excluded from the present study.

Results

Among 27 patients with a median age of 30.5 (18–44) years, only one was female with a rare left-non-coronary cusp fusion type. The prevalence of root phenotype was markedly higher in RL patients (56.3% vs 9.1%, p=0.018). In RL patients, the numbers of rare genetic variants (RGVs) were 15 in extracellular matrix genes, 8 in TGF-β signaling pathway genes, 2 in smooth muscle cell contraction apparatus genes, and 3 in familiar BAV related genes. In non-RL patients, the number of RGVs were 15, 3, 4, and 5, respectively. On the other hand, the number of RGVs in above gene clusters were 9, 6, 3, 2 in patients with a root phenotype, and 21, 5, 3, 6 in those without. Eight recurrent genetic variants were identified in 6 genes (see Table). An interesting observation was that ADAMTS2 variants were exclusively found among non-RL patients without root phenotype, as FBN2 variants among RL patients with root phenoype.

Recurrent Rare Genetic Variants Gene Reference sequence Variant 1000G 1000G-East Asia Patients TGFBR2 NM_001024847.2 p.Val216Ile/c.646G>A 0.004 0.018 A16, A23 TGFBR2 NM_001024847.2 p.Thr340Met/c.1019C>T 0.003 0.015 A03, A05, A07 ADAMTS2 NM_014244.4 p.Gly1169Val/c.3506G>T 0.0044 0.021 A03, A15 FBN2 NM_001999.3 p.Gly475Val/c.1424G>T 0.0004 0.002 A19, A24 ELN NM_001278939.1 p.Pro93Leu/c.278C>T 0.0014 0.0069 A22, A26 COL4A5 NM_033380.2 p.Gly953Val/c.2858G>T 0.0079 0.03 A11, A17 MYLK NM_053025.3 p.Ser243Trp/c.728C>G 0.0002 0.001 A01, A02 MYLK NM_053025.3 p.Asp717Tyr/c.2149G>T 0.0024 0.011 A04, A21

Conclusion

Recurrent genetic variants could be identified in a cohort of early-onset BAVD patients with isolated severe aortic regurgitation and staggering male predominance. The incidence and clinical relevance of these variants should be validated in an extended real-world BAV cohort.

P4348Early assessment of left ventricular function by layer-specific strain and its relationship to pulsatile arterial load in patients with coronary slow flow

Background

Previous studies reported controversial Left ventricular (LV) function impairment and pathophysiology in patients with coronary slow flow (CSF). Greater arterial load has been shown to increase aortic impedance and endothelial shear stress, potentially affecting coronary anatomy and function. We investigated LV systolic function by a new layer-specific strain technology and assessed the association between pulsatile arterial load and contractility.

Methods and results

A total of 70 patients with CSF and 50 controls with normal coronary angiography were included in the study. Layer-specific longitudinal and circumferential strains were assessed from endocardium, mid-myocardium and epicardium (GLS-endo, GLS-mid, GLS-epi and GCS-endo, GCS-mid, GCS-epi) by two-dimensional speckle tracking imaging (2D-STI). Pulsatile arterial load was estimated by indexed arterial compliance (ACI). Layer-specific GLS showed a decreasing gradient from the endocardium to the epicardium in both controls and CSF group. GLS-endo and GLS-mid in CSF group were significantly lower than the control group (all P<0.05). Layer-specific longitudinal strain showed a good correlation with the number of affected coronary arteries (all P<0.05) and the mean thrombolysis in myocardial infarction frame count (TFC) (all P<0.05). ACI was lower in CSF patients (P=0.005) and ACI was correlated negatively with layer-specific GLS (all P<0.05).

Conclusion

Layer-specific evaluation of the LV provides an understanding of the layer-specific properties of the LV wall and the possible process of the LV impairment in patients with CSF. Greater pulsatile arterial load, as manifested by a lower ACI, is coupled with worse LV longitudinal function in CSF patients.

P916The effect of a novel, user-friendly, transcatheter edge-to-edge mitral valve repair device in a porcine model of mitral regurgitation

Objective

A new technique has been devised to treat mitral regurgitation (MR) through the transapical route by replicating the edge-to-edge repair surgery. This system encompasses an easy-to-use leaflet clamp and a smaller-sized delivery system (14F–16F). We aimed to evaluate the effectiveness of this device in a porcine model of acute MR.

Methods

Acute MR was induced in 36 anesthetized porcine subjects by severing the major chordae supporting the corresponding segment of the leaflet. This device was then transapically implanted on the prolapsing segment under 3D epicardial echocardiographic guidance. All of the animals were killed 30 days after the procedure to verify the proper location of the implanted devices.

Results

Cutting the major chordae induced an eccentric MR jet (MR grade: 3+, 27.8%/4+, 72.2%) in all of the animals. Every single pig was then successfully implanted with one clamp. The duration of catheterization ranged from 18 to 40 minutes. Overt MR reduction was observed following the procedure through echocardiography; residual MR was mild in 8 cases, trivial in 19 cases, and absent in 9 cases. In terms of hemodynamic parameters, the mean and maximum mitral valve pressure gradients were increased significantly (p<0.01), but these values were less than 4 mmHg in all of the cases. Autopsy demonstrated that all but one device were precisely placed to clip the prolapsing segment of the mitral valve, and there was no evidence of thrombosis, thromboembolism or impairment of the cardiac structure.

Table 1. Changes in hemodynamic parameters, cardiac size, and functional parameters after the procedure Preoperation Postoperation P value MR-maxA (mm2) 7.27±2.13 1.54±1.29 0.000 MVPG-max (mmHg) 1.95±0.47 3.66±0.62 0.000 MVPG-mean (mmHg) 0.87±0.31 1.7±0.28 0.000 LVEDD (mm) 46.08±2.85 46.44±3.53 0.239 LVESD (mm) 29.11±3.44 29.08±3.62 0.940 LVEF (%) 66.53±6.4 67.14±4.93 0.256 LAD (mm) 35.75±2.24 36.42±1.99 0.057 LAA (mm2) 12.95±2.22 12.64±1.55 0.301

Figure 1

Conclusions

Transapical implantation of the novel mitral valve repair device is effective and safe in reducing acutely induced MR in pigs; thus, suggesting that it has great potential for clinical benefit in patients with MR.

Acknowledgement/Funding

Shanghai Science and Technology Committee

P711Histamine promotes atherosclerotic plaque instability via STAT6-dependent macrophage pyroptosis

Background

Atherosclerotic plaque formation and rupture is the primary cause for cardiovascular diseases. It's known that cell death and inflammation are crucial processes leading to atherosclerosis, which involves an important role of histamine. The aim of the present study is to determine the function of signal transducer and activator of transcription 6 (STAT6) in histamine-induced macrophage pyroptosis and plaque instability.

Methods

We constructed APOE/STAT6 double knock out (DKO) mice via hybridization of ApoE−/− and STAT6−/− mice. 20 ApoE−/− mice (control) and 20 DKO mice were challenged with high-fat diet for 12 weeks while 10 in each group were intraperitoneally infused with histamine (400ug/kg) every other day. The extent and instability of atherosclerotic plaque were determined by oil-red staining, HE staining, immunofluorescence staining and electron microscopy. Changes in subsets of immune cells were evaluated by flow cytometry. Plasma cytokines were assessed by ELISA. Microarray analysis was applied to detect gene expressions while Western blot and real-time PCR was used to assess gene expression levels.

Results

Morphology studies revealed that histamine could promote plaque formation and vulnerability in ApoE−/− mice, whereas this effect was inhibited in DKO mice. FACS data showed that histamine injection could increase CD11b+Ly6Chigh M1 macrophages differentiation and pyroptosis and facilitate foam cells formation in ApoE−/− mice, which was also inhibited in DKO mice. Microarray analysis and in vitro studies exhibited that histamine could induce the up-regulation of pyrotosis-related proteins such as NLRP3, caspase-1 and MMPs via a STAT6-dependent pathway to promote macrophage pyroptosis and foam cell formation.

Conclusions

We have characterized a novel role for histamine in modulating atherosclerotic lesion development and progression. Moreover, our work have figured out the detailed mechanisms by which histamine modulates the pyroptosis of macrophages and the progress of unstable atherosclerotic plaques. We envision that this study may provide several potential therapeutic targets benefit for atherosclerosis treatment.

P4378Comparison between left bundle branch pacing and His bundle pacing using two-dimensional speckle tracking echocardiography

Background

Although his bundle pacing (HBP) can achieve physiological electrical activation of the ventricles, its clinical use is limited by lower success rates, high and unstable pacing thresholds and loss of capture. Left bundle branch pacing (LBBP) has been proved to be able to correct Left bundle branch block (LBBB) and generate a narrower QRS duration than conventional RV pacing. However, its effects on ventricular synchronism and contraction function remains unknown. The current study is aimed to compare the echocardiographic characteristics between HBP and LBBP, and to explore whether LBBP leads to a comparable cardiac synchrony and deformation in comparison with HBP.

Methods

Forty-six pacing-indicated patients were prospectively enrolled. Twenty-nine patients underwent LBBP (17 male patients, mean age 69.6±13.7yrs, the LBBP group) and 17 patients underwent HBP (13 male patients, mean age 70.4±14.7yrs, the HBP group). LBBP was achieved by trans-septal method in the basal ventricular septum. Left ventricular end diastolic volume (LVEDV), left ventricular end systolic volume (LVESV), left ventricular ejection fraction (LVEF), and tricuspid annulus plane systolic excursion (TAPSE) were obtained. Strains and time to peak strains of right ventricular free wall and 16 left ventricle segments were analyzed using two-dimensional speckle tracking echocardiography (2D STE). The standard deviation of time to peak strains of 16 left ventricular segments was calculated as PSD.

Results

Compared to the baseline, time to peak longitudinal strain (TTPS) of apical septum, apical lateral wall were shortened after 6 months of HBP, while they didn't change significantly after 6 months of LBBP. After pacemaker implantation, the LBBP group had a delayed TTPS of apical septum, apical lateral wall and basal RV free wall than the HBP group (LBBP vs. HBP: apical septum,358.44±61.98ms vs. 296.43±29.47ms; apical lateral wall, 373.11±55.80ms vs. 299.00±83.45ms; basal RV free wall, 404.31±72.93ms vs. 334.50±39.95ms, all p<0.05).However, PSD was comparable between the two groups (p>0.05).

Compared to the baseline, global left ventricular longitudinal strain (LVGLS) and longitudinal strain of RV free wall (RVLS) were deteriorated after 6 months of HBP, while they were preserved in the LBBP group. After 6-month pacing, LVGLS and RVLS were significantly stronger in the LBBP group than those in the HBP group. (LVGLS, −16.10±3.75% vs. −13.18±4.11%; RVLS, −17.50±5.46% vs. −13.70±4.35%, both p<0.05).

Conclusion

Patients received LBBP had a comparable left ventricular synchronism and a better myocardial contraction compared to patients with HBP. LBBP may be a promising alternative pacing strategy. Two-dimensional STE is more sensitive than conventional echocardiography in assessing cardiac synchrony and segmental deformation.

The role of Ca2+ in acid-sensing ion channel 1a-mediated chondrocyte pyroptosis in rat adjuvant arthritis

Rheumatoid arthritis is an autoimmune disease with a poor prognosis. Pyroptosis is a type of proinflammatory programmed cell death that is characterised by the activation of caspase-1 and secretion of the proinflammatory cytokines interleukin (IL)-1β/18. Previous reports have shown that pyroptosis is closely related to the development of some autoimmune diseases, such as rheumatoid arthritis. The decrease in the pH of joint fluid is a main pathogenic feature of RA and leads to excessive apoptosis in chondrocytes. Acid-sensitive ion channels (ASICs) are extracellular H⁺-activated cation channels that mainly influence Na⁺ and Ca²⁺ permeability. In this study, we investigated the role of Ca²⁺ in acid-sensing ion channel 1a-mediated chondrocyte pyroptosis in an adjuvant arthritis rat model. The expression of apoptosis-associated speck-like protein, NLRP3, caspase-1, ASIC 1a, IL-1β and IL-18 was upregulated in the joints of rats compared with that in normal rats, but the expression of Col2a in cartilage was decreased. However, these changes were reversed by amiloride, which is an inhibitor of ASIC1a. Extracellular acidosis significantly increased the expression of ASIC1a, IL-1β, IL-18, ASC, NLRP3 and caspase-1 and promoted the release of lactate dehydrogenase. Interestingly, Psalmotoxin-1 (Pctx-1) and BAPTA-AM inhibited these effects. These results indicate that ASIC1a mediates pyroptosis in chondrocytes from AA rats. The underlying mechanism may be associated with the ability of ASIC1a to promote [Ca²⁺]_i and upregulate the expression of the NLRP3 inflammasome.

[Changes of intestinal mucosal barrier in mice with chronic ulcerative colitis]

Objective: To study the damage and mechanism of intestinal mucosal barrier function in mice with ulcerative colitis induced by Dextran sulphate sodium (DSS). Methods: Mice models of chronic ulcerative colitis induced by DSS were established. The mice were completely randomized into normal control group and DSS group, 25 mice in each group. The body weight and colon length of the mice were monitored. The pathological examination of colon tissue was confirmed the success of the model and assessed the integrity of the colonic mucosal barrier; Evan's Blue's intestinal permeability analysis assessed the function of colon mucosal barrier; immunofluorescence staining and Western blot were used to evaluate the expression of intestinal mucosal barrier integrity-related proteins. Results: Compared with the normal control group, the DSS group had lower body weight [(25.6±0.7)g vs (23.5±0.7)g, t=2.14, P<0.05], and the colon length was shorter [(7.3±0.4)cm vs (5.6±0.2)cm, t=3.975, P<0.001]; colonic pathological results showed that the intestinal mucosa became thinner and part of the intestinal mucosa was defective; Evan's Blue instilled into the intestinal lumen was more abundant into the intestinal mucosa, and the optical density at 620 nm (OD(620))/colon tissue weight (g) was higher [(0.11±0.01) vs (0.15±0.01), t=4.174, P<0.05]; immunofluorescence and Western blot results showed lower expression of ZO-1, Claudin-1, and F-actin in colonic mucosa. Conclusion: The structure and function of intestinal mucosal barrier in DSS-induced chronic ulcerative colitis mice is impaired.

Transport stress induces heart damage in newly hatched chicks via blocking the cytoprotective heat shock response and augmenting nitric oxide production

Transport stress affects the animal's metabolism and psychological state. As a pro-survival pathway, the heat shock response (HSR) protects healthy cells from stressors. However, it is unclear whether the HSR plays a role in transport stress-induced heart damage. To evaluate the effects of transport stress on heart damage and HSR protection, newly hatched chicks were treated with transport stress for 2 h, 4 h and 8 h. Transport stress caused decreases in body weight and increases in serum creatine kinase (CK) activity, nitric oxide (NO) content in heart tissue, cardiac nitric oxide syntheses (NOS) activity and NOS isoforms transcription. The mRNA expression of heat shock factors (HSFs, including HSF1-3) and heat shock proteins (HSPs, including HSP25, HSP40, HSP47, HSP60, HSP70, HSP90 and HSP110) in the heart of 2 h transport-treated chicks was upregulated. After 8 h of transport stress in chicks, the transcription levels of the same HSPs and HSF2 were reduced in the heart. It was also found that the changes in the HSP60, HSP70 and HSP90 protein levels had similar tendencies. These results suggested that transport stress augmented NO generation through enhancing the activity of NOS and the transcription of NOS isoforms. Therefore, this study provides new evidence that transport stress induces heart damage in the newly hatched chicks by blocking the cytoprotective HSR and augmenting NO production.