Single-cell transcriptome analysis yields new insights into the pathogenic mechanisms and possible genetic etiology of cardiomyopathies

Background

Inherited cardiomyopathies (CM) represent a clinically heterogeneous group of primary cardiac muscle disorders with a strong genetic underpinning. Recent rapid genomic advances have led to the identification of numerous disease-causing genes for both non-syndromic (nsCM) and syndromic (sCM) cardiomyopathies. This has greatly facilitated molecular genetic testing, thus enabling accurate disease diagnosis needed for the practice of precision medicine and the optimization of patient outcome. However, many cardiomyopathies remain unexplained with the known genes and dominant genetic model of disease.

Purpose

To reassess the genetic features of known CM genes as a strategy to recover novel candidate CM genes.

Methods

Known hypertrophic CM (HCM), dilated CM (DCM) and pediatric CM genes were curated from the literature and from 23 commercial CM diagnostic panels. They were classified as non-syndromic and syndromic, and further annotated using two constraint metrics, the missense Z score and pLI score obtained from the GnomAD database. Publicly available mouse (n=6) and human (n=3) single-cell RNA (scRNA) datasets were downloaded and cardiomyocyte specific differentially expressed genes (DEGs) (fold change >0.1; adjusted P<0.0001) were recovered. Genes identified as DEGs in at least 4 mouse or 3 human scRNA datasets were recovered as nsCM candidate genes.

Results

Analyses of 9 scRNA datasets showed the majority of known nsCM genes are cardiomyocyte specific (Fig. 1a-b). nsCM and sCM genes have distinct expression and genetic profile. nsCM genes are associated with higher heart expression and lower loss intolerance (Fig. 1c). In contrast, syndromic CM genes mostly showed lower expression with high loss intolerance, consistent with their higher clinical impact. However, interestingly some of the nsCM genes (MYLK2, TMPO and KLF10) show low or even no detectable expression in mouse and human cardiac cells. Using the scRNA data, we assessed cellular expression of genes in the 23 commercial CM diagnostic panels. This analysis showed some of the CM genes with high cardiomyocytes expression have low coverage on the current commercial CM panels (Fig. 1d). Using human and mouse scRNA data, we recovered 224 mouse and 157 human nsCM candidate genes. MTUS2 (microtubule-associated tumor suppressor candidate 2) was identified as a strong nsCM candidate gene supported by evidence from both mouse and human studies (Fig. 1e-f).

Conclusions

Our analysis showed many of the nsCM genes have differential cardiomyocyte expression with low loss intolerance, while the reverse was observed for many sCM genes. We propose increasing commercial panel coverage of cardiomyocytes-specific expressed genes may help increase disease diagnostic yield. Additionally, novel candidate genes uncovered trained on cardiomyocyte expression profile may help accelerate elucidation of unsolved cardiomyopathy cases.

Funding Acknowledgement

Type of funding sources: None.

P–501 Deep in the Maze: The psychosocial trajectory and decision making of Women with recurrent implantation failure of IVF

Study question

To understand the psychosocial trajectory of Chinese women who have experienced recurrent implantation failure (RIF) of IVF and their decision making accordingly.

Summary answer

Chinese women experience despair, doubt, and disorientation along with the cumulative failure cycles of IVF, and stick to IVF as the ultimate option.

What is known already

Recurrent implantation failure, the absence of implantation after repeated embryo transfers is a stressful event for people undergoing treatment for infertility. Numerous researches have focused on the psychological wellness of women undertaking IVF, but pay less attention to the subgroup who have undergone repeated failures. Current studies have shown that women after repeated unsuccessful IVF might endure anxiety, depression, and other psychosocial distress; however, the feelings brought by the different times of failure are unlike, and these experiences will affect their treatment decisions accordingly, which is rarely studied.

Study design, size, duration

Semi-structured interview was adopted with sixteen Chinese women from March 2020 to July 2020. The interview lasted 90 minutes. A follow-up survey was conducted three months after the interview. Driven by grounded theory, data is analyzed by thematic analysis.

Participants/materials, setting, methods

Convenience sampling was used to recruit female participants who have failed to achieve clinical pregnancy after two consecutive cycles of fresh or frozen IVF embryo transfers with a cumulative number of transferred embryos of four or more cleavage-stage embryos or two or more blastocysts. Chinese-speaking women who were undertaking IVF treatment in the reproductive center of hospital in Shenzhen City were recruited by pamphlets and doctors’ referral.

Main results and the role of chance

Chinese women with recurrent implantation failures experience the following psychosocial trajectory during the cumulative failure cycles of IVF: despair, doubt, and disorientation. Despair usually comes after the first failure: the high expectation for success rates makes the initial failure exceptionally shocking and desperate. Huge distress brings two kinds of decisions: start a new IVF cycle quickly to welcome the positive results in the imagination, or wait for a period of time to avoid the pain of failure again. Doubt usually appears after the second failure. In addition to doubting the health function of their body, recurrent failure makes the patients particularly doubt the efficacy of IVF and doctors’ clinical judgment. Some patients would do ‘hospital shopping’ and consider change clinics. Disorientation can be seen in patients who have experienced more than three cycles of failure. Past experience and meaning cannot help them understand and solve the current dilemma. The inherent concept of fertility continues to strengthen their belief of having a baby as ultimate goal. The follow-up survey found that most women still choose to continue IVF treatment after repeated failure. They are like being in the maze of fertility, wandering for a long time but unable to get out.

Limitations, reasons for caution

Several limitations are identified: self-selection bias due to convenience sampling; narrow sampling approach may limits the generalizability; the exclusion of men may ignore the marital interdependence during the infertility treatment.

Wider implications of the findings: Patients who have experienced recurrent implantation failure demand promising intervention during and after infertility treatment. The findings demonstrate the need for both supportive and implication counseling to facilitate them cope with the psychosocial distress, and make value-based decision making, so as to enhance their self-agency.

Trial registration number

Not applicable

[Regulatory effects of LIM kinase 1 on the proliferation and metastasis of hepatocellular carcinoma cells]

Objective: To study LIM kinase 1 (LIMK1) expressional condition, and its regulatory effects on the proliferation and metastasis of hepatocellular carcinoma cells and tissues. Methods: The online database starBase v3.0 and GEPIA were used to analyze the LIMK1 expression in hepatocellular carcinoma cells and normal liver tissues, and then the relevant survival analysis was performed. LIMK1 expression in hepatocellular carcinoma cell line was analyzed by Western blot. Hep3B and Huh7 cells were transiently transfected after LIMK1 protein expression was down-regulated by small interfering RNA (siRNA). LIMK1 effects on the proliferation of Hep3B and Huh7 cells were observed by MTT assay and colony formation assay. Transwell assay was used to detect the change in metastatic ability of hepatocellular carcinoma cell after the down-regulation of LIMK1 expression. Western blot was used to detect the changes of related indexes in the process of epithelial mesenchymal transition after the down-regulation of LIMK1 expression. Data were analyzed by one-way ANOVA. Results: The expression level of LIMK1 in liver cancer tissues was significantly higher than that of normal liver tissues, and was related with prognosis (P ​< 0.01). Furthermore, LIMK1 expression in HCC cell lines was significantly higher than that of immortalized liver L02 cells (P < 0.05). Functional correlated experiment showed that the proliferation and metastatic ability of liver cancer cells were significantly inhibited after LIMK1 expression down-regulation (P < 0.05). Simultaneously, LIMK1 was also involved in the process of epithelial-mesenchymal transition. Conclusion: LIMK1 was overexpressed in HCC tissues and cells, and may regulate the proliferation and metastasis of HCC cells and participate in epithelial-mesenchymal transition process.

POS0417 EXOGENOUS CXCL5 RESTORES ENDOGENOUS BLOOD-TISSUE CHEMOKINE GRADIENT TO IMPROVE SURVIVAL IN MURINE LUPUS

Background:

Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disease that is potentially fatal. There is an unmet need to improve current therapies. In patients with SLE, we observed that serum CXCL5 levels were significantly lower than healthy control subjects and negatively correlated with disease activity(1-9).

Objectives:

The aim of this study is to elucidate the effect of supplemental serum CXCL5 in abrogating the pathological processes of SLE.

Methods:

Ten doses of exogenous CXCL5 (3µg/kg) was administered to 16-week-old Faslpr mice weekly by intravenous injection. Mice were monitored for 10 weeks. Splenic immune profile was measured by flow cytometry. Circulating cytokine and immunoglobulin profile were detected by Luminex technology. Renal function was evaluated by urinary spot albumin creatinine ratio. In situ renal immune cell infiltration and complement 3 deposition were detected by Haematoxylin and Eosin (H&E) and immunohistochemistry staining. The molecular pathways involved were examined by RNA sequencing.

Results:

In Faslpr mice, intravenous administration of exogenous CXCL5 significantly improved mouse survival with concomitant reduction of autoantibody secretion, proteinuria, complement 3 deposition, neutrophil infiltration and lupus nephritis classes. Through evaluating the changes of immune profile, cytokine profile and molecular pathways, we found that intravenous CXCL5 reduced inflammation via an orchestral effect of regulating neutrophil trafficking and modulating helper T cell-mediated immune response. Pharmacokinetic and real-time Polymerase Chain Reaction studies further demonstrated that this orchestration was triggered by a cascade reaction - restoring vascular under-expressed CXCL5 by an exogenous stimulation, re-establishing the normal serum levels of endogenous CXCL5 and reverting the CXCL5 chemokine gradient between inflamed tissues and blood circulation.

Conclusion:

Managing the dysregulation of CXCL5 by exogenous supplement may provide a new option for SLE therapy.

References:

[1]Dufies M, Grytsai O, Ronco C, et al. New CXCR1/CXCR2 inhibitors represent an effective treatment for kidney or head and neck cancers sensitive or refractory to reference treatments. Theranostics. 2019;9(18):5332-5346. doi:10.7150/thno.34681

[2]Yildirim K, Colak E, Aktimur R, et al. Clinical Value of CXCL5 for Determining of Colorectal Cancer. Asian Pac J Cancer Prev. Sep 26 2018;19(9):2481-2484. doi:10.22034/apjcp.2018.19.9.2481

[3]Wu K, Yu S, Liu Q, Bai X, Zheng X. The clinical significance of CXCL5 in non-small cell lung cancer. Onco Targets Ther. 2017;10:5561-5573. doi:10.2147/ott.s148772

[4]Zhao J, Ou B, Han D, et al. Tumor-derived CXCL5 promotes human colorectal cancer metastasis through activation of the ERK/Elk-1/Snail and AKT/GSK3beta/beta-catenin pathways. Mol Cancer. Mar 29 2017;16(1):70. doi:10.1186/s12943-017-0629-4

[5]Han KQ, Han H, He XQ, et al. Chemokine CXCL1 may serve as a potential molecular target for hepatocellular carcinoma. Cancer Med. Oct 2016;5(10):2861-2871. doi:10.1002/cam4.843

[6]Pappa CA, Tsirakis G, Kanellou P, et al. Monitoring serum levels ELR+ CXC chemokines and the relationship between microvessel density and angiogenic growth factors in multiple myeloma. Cytokine. Dec 2011;56(3):616-20. doi:10.1016/j.cyto.2011.08.034

[7]Zhang L, Li H, Ge C, et al. CXCL3 contributes to CD133(+) CSCs maintenance and forms a positive feedback regulation loop with CD133 in HCC via Erk1/2 phosphorylation. Sci Rep. Jun 3 2016;6:27426. doi:10.1038/srep27426

[8]Matsubara J, Honda K, Ono M, et al. Reduced plasma level of CXC chemokine ligand 7 in patients with pancreatic cancer. Cancer Epidemiol Biomarkers Prev. Jan 2011;20(1):160-71. doi:10.1158/1055- 9965.epi-10-0397

[9]Ma Y, Ren Y, Dai ZJ, Wu CJ, Ji YH, Xu J. IL-6, IL-8 and TNF-alpha levels correlate with disease stage in breast cancer patients. Adv Clin Exp Med. May-Jun 2017;26(3):421-426. doi:10.17219/acem/62120

Disclosure of Interests:

None declared

Identification of a mitogen-activated protein kinase kinase (AccMKK4) from Apis cerana cerana and its involvement in various stress responses

The mitogen-activated protein kinase (MAPK) cascade pathway is a ubiquitous signal transduction pathway in eukaryotes that regulates a variety of immune responses. This study accomplished the first isolation of an AccMKK4 gene from Apis cerana cerana and explored its function. Yeast two-hybrid experiments proved that AccMKK4 can interact with Accp38b, and the silencing of AccMKK4 in honeybees downregulated the expression level of Accp38b, which suggests that AccMKK4 might participate in the oxidative stress response through the p38 MAPK pathway. Tissue-specific expression levels of AccMKK4 analysis showed that AccMKK4 in the thorax, particularly muscle tissue, was higher than that in other tissues. The qRT-PCR results from different conditions demonstrated that AccMKK4 responds to various environmental stresses. After AccMKK4 silencing, the transcription level of some antioxidant genes and the activity of antioxidant-related enzymes are reduced, which indicated that AccMKK4 plays an important role in resistance against oxidative stress caused by external stimuli. In summary, our findings indicate that AccMKK4 probably plays an indispensable role in the response of honeybees to environmental stress and might aid for further research on the role of the MAPK cascade pathway in the antioxidant defence mechanisms of insects.

The continuous application of biochar in field: effects on P fraction, P sorption and release

It is unclear how biochar can affect P availability in soil, especially in field under continuous application. In this study, a field experiment was conducted to study the effect of 2-years application of biochar on P availability, P fractionation, P sorption and release in a clay soil. The biochar in this study was produced from rice straw through pyrolysis at 700°C. As compared with no fertilizer treatment (CK) and chemical fertilizer treatment (CF), the biochar application with chemical fertilizer treatment (BCF) significantly increased total P and available P content in soil. And BCF treatment significantly increased resin P, NaHCO₃-extracted P, Fe/Al-P_o and HCl-extracted P but decreased Fe/Al-P_i and residual P as compared with CF treatment. Surprisingly, BCF treatment showed higher sorption capacity and release capacity of soil P than that of CF treatment. These results imply that continuous application of biochar for 2-years in field may adsorbed P through physical sorption rather than chemical reaction and then improve P availability in soil.

[Predictive value of N-terminal B-type natriuretic peptide on outcome of elderly hospitalized non-heart failure patients]

Objective: To investigate the predictive value of N-terminal type B natriuretic peptide（NT-proBNP) on the prognosis of elderly hospitalized patients without heart failure（non-heart failure). Method: Elderly patients aged 65 years or older, who were admitted to Beijing Hospital from September 2018 to February 2019, were enrolled in this study. Patients with clinical diagnosis of heart failure or left ventricular ejection fraction（LVEF)<50% were excluded. The patients were divided into 2 groups based on the serum NT-proBNP level: low NT-proBNP group （<125 ng/L) and high NT-proBNP group（≥125 ng/L). Patients were followed up at 3, 6, and 12 months after enrollment, and the major adverse events were recorded. The composite endpoint events included all-cause mortality, readmission or Emergency Department visits. Cardiovascular events include death, readmission or emergency room treatment due to cardiogenic shock, myocardial infarction, angina pectoris, arrhythmia, heart failure or stroke/transient ischemic attack. Results: A total of 600 elderly patients with non-heart failure were included in the analysis. The average age was （74.9±6.5) years, including 304（50.7%) males. The median follow-up time was 344（265, 359) days. One hundred and seventy-eight（29.7%) composite endpoint events were recorded during the follow-up, 19（3.2%) patients died, and 12（2.0%) patients were lost to follow-up. There were 286(47.7%) cases in low NT-proBNP group and 314 cases（52.3%) in high NT-proBNP group. Patients were older, prevalence of atrial fibrillation and myocardial infarction was higher; MMSE scores and ADL scores, albumin and creatinine clearance rate were lower in high NT-proBNP group than in low NT-proBNP group（all P<0.05). At 1-year follow-up, the incidence of composite endpoint events was significantly higher in high NT-proBNP group than in low NT-proBNP group（33.4%（105/314) vs. 24.8%（71/286), P = 0.02). Cardiovascular events were more common in high NT-proBNP group than in low NT-proBNP group（17.5%（55/314) vs. 8.4%（24/286), P = 0.001). Kaplan-Meier survival analysis showed both composite endpoint events（Log-rank P=0.016) and cardiovascular events（Log-rank P=0.001) were higher in high NT-proBNP group than in low NT-proBNP group. All-cause mortality was also significantly higher in highNT-proBNP group than in lowNT-proBNP group（4.8%（15/314) vs. 1.4%（4/286), P = 0.020), and Kaplan-Meier survival analysis demonstrated borderline statistical significance（Log-rank P = 0.052). Cox proportional hazard regression analysis showed that after adjusting for age, sex, creatinine clearance rate, myocardial infarction, and atrial fibrillation, NT-proBNP remained as an independent risk factor for composite endpoint events（HR=1.376，95%CI 1.049-1.806, P=0.021), and cardiovascular events（HR=1.777, 95%CI 1.185-2.664, P=0.005), but not for all-cause mortality（P=0.206). Conclusions: NT-proBNP level at admission has important predictive value on rehospitalization and cardiovascular events for hospitalized elderly non-heart failure patients. NT-proBNP examination is helpful for risk stratification in this patient cohort.

[Application of pump-controlled retrograde trial off in weaning from veno-arterial extracorporeal membrane oxygenation in adult patients]

Objective: To Summarize the experience of pump-controlled retrograde trial off (PCRTO) in the process of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) withdrawal in adult patients. Methods: Adult patients who received ECMO assistance in Intensive Care Unit for Cardiac Surgery from March to July 2019 were collected. According to our strategies, PCRTO was used if the patients can wean from VA-ECMO and hemodynamic indexes were recorded during the process. The statistics data was collected, including the 48 hours survival rate, ECMO re-assistance rate, thrombus complications, Intensive Care Unit (ICU) stay time and hospital stay time after weaning from VA-ECMO. The patients who failed in the test were continued to be assisted by ECMO. Results: There were 46 patients assisted by VA-ECMO in our center. In total, 21 adults who met the offline test standard underwent 26 PCRTOs, including 10 male adults (47.6%), with an age of 65 (55, 68) years old. Eighteen adults passed the withdrawal test. No new thrombus was found in the arteriovenous ultrasound of the lower extremity after weaning from ECMO, and no pulmonary embolism was found in the chest X-ray. The success rate of weaning from ECMO was 69.23%(18/26). The D-dimer decreased [584(348,2 107)μg/L vs 1 440(631,2 916)μg/L, P=0.014] and the left ventricular ejection fraction (LVEF) increased (51.4%±8.5% vs 46.9%±10.6%, P=0.013) on the next day after weaning. There were significant differences in heart rate (HR), central venous pressure (CVP), oxygenation index and lactate (Lac) during the PCRTO in the group which involved the cases of the 8 failed experiments (all P<0.05). Compared with the failure group, there were significant differences in age, blood flow rate, CVP before the test, HR, pulse oxygen saturation(SpO(2)), CVP, Lac and oxygenation index after the test, and the variations of SpO(2), CVP and Lac. Conclusion: PCRTO is a simple, reversible, safe and effective weaning method. It can be used in the process of VA-ECMO withdrawal in adult patients.

[Predictors for perioperative blood loss in pediatric patients with congenital scoliosis]

Objective: To identify predictors of massive blood loss after posterior hemivertebra resection for patients with congenital scoliosis. Methods: The data of 106 children with congenital scoliosis were collected from June 2017 to June 2019 in Beijing Children's Hospital. All the cases received posterior hemivertebra resection and internal fixation. The blood volume was estimated by weight and height. The visible blood loss was recorded according to medical record, and the hidden blood loss was calculated by OSTHEO formula. Perioperative information including age, gender, height, weight, Cobb and kyphosis angle, level fused, number of screws, operative time, and laboratory examinations was collected. Then multivariable linear regression was performed to determine the independent risk factors of blood loss. Results: All the surgeries were completed successfully. The mean age of the children was (7.3±2.3) years and the operative time was (162±56) min. The mean fused levels were 3 and the correction rate for deformity was 78.4%. The amount of blood loss was (568±208) ml which accounted for 42.3% of total blood volume. The visible and hidden blood loss was (334±193) ml and (234±199) ml, respectively, and which accounted for 58.8% and 41.2% of total blood loss. Multivariable linear regression analysis indicated that age, preoperative Cobb angle, the time of surgery and the number of fused levels were independent risk factors of total blood loss. Preoperative Cobb angle ≥40°, spinal fusion ≥4 levels and operative duration ≥140 min indicated more blood loss (all P<0.05). Conclusions: The perioperative blood loss of congenital scoliosis is massive with a high percentage of hidden blood loss. The patients with severe deformity, more fused levels and increased operative time brings higher risk of massive blood loss.

Hypomethylation of Notch1 DNA is associated with the occurrence of uveitis

Uveitis is a serious intra-ocular inflammatory disease that can lead to visual impairment even blindness worldwide. Notch signaling can regulate the differentiation of naive CD4⁺ T cells, influencing the development of uveitis. DNA methylation is closely related to the autoimmune diseases. In this study, we measured the Notch1 DNA methylation level, determined the Notch1 and related DNA methylases mRNA expression and evaluated the ratio of T helper type 17 regulatory T cell (Th17/T_reg ) in peripheral blood mononuclear cells (PBMCs) from uveitis patients and normal control subjects; we also tested the levels of relevant inflammatory cytokines in serum from the participants. Results indicated that compared with those in normal control individuals, the expression of ten-eleven translocation 2 (TET2) and Notch1 mRNA is elevated in uveitis patients, whereas the methylation level in Notch1 DNA promotor region [-842 ~ -646 base pairs (bp)] is down-regulated, and is unrelated to anatomical location. Moreover, the Th17/T_reg ratio is up-regulated in PBMCs from uveitis patients, accompanied by the elevated levels of proinflammatory cytokines [e.g. interleukin (IL)-2, IL-6, IL-17 and interferon (IFN)-γ] in serum from uveitis patients. These findings suggest that the over-expression of TET2 DNA demethylase may lead to hypomethylation of Notch1, activate the Notch1 signaling, induce naive CD4⁺ T cells to differentiate theTh17 subset and thus disturb the balance of the Th17/T_reg ratio in uveitis patients. Overall, hypomethylation of Notch1 DNA is closely associated with the occurrence of uveitis. Our study preliminarily reveals the underlying mechanism for the occurrence of uveitis related to the hypomethylation of Notch1 DNA, providing a novel therapeutic strategy against uveitis in clinical practice.

AB0128 CXCL5 DAMPENS INFLAMMATION IN THE PRE-CLINICAL MODEL OF SYSTEMIC LUPUS ERYTHEMATOSUS VIA THE ORCHESTRAL EFFECT OF REGULATING NEUTROPHIL TRAFFICKING AND SUPPRESSING HELPER T CELL-MEDIATED IMMUNE RESPONSE

Background:

Patients with systemic lupus erythematosus (SLE) suffer from severe morbidity and mortality1-4, either from the disease itself or from side effects of immunosuppression5. Discovery of novel effective therapies with less toxicity is an urgent need.

Objectives:

The aim of this study is to elucidate the therapeutic potential and working mechanism of cytokine CXCL5 in lupus mice.

Methods:

Treatment with CXCL5, bone marrow (BM)-MSCs, standard of care (SOC) with combination of methylprednisolone and cyclophosphamide was given to 16-week-old Faslprmice. Mice were monitored for 10 weeks. Splenic immune cell subsets were measured by flow cytometry. Circulating cytokine and immunoglobulin were detected by Luminex technology. Renal function was evaluated by urinary spot albumin creatinine ratio. In situ renal immune cell infiltration and complement 3 deposition were detected by Haematoxylin and Eosin (H&E) staining and immunohistochemistry.

Results:

CXCL5 demonstrated consistent and potent immunosuppressive capacity in suppressing SLE with reduced autoantibody secretion, lymphoproliferation and preserved kidney function. With further exploration, we proved that CXCL5 reduced the proliferation of helper T cells (TH1 and TH2) in thein vitrofunctional assay. When we administrated CXCL5 to lupus mice, it promoted the proliferation of regulatory T cells and reduced the proliferation of TH17 cells, macrophages and neutrophils. Multiple proinflammatory cytokines including IL-2, IL-6, IL-12, IL-17A, KC/CXCL1, MIP-1β/CCL4 and TNF-α were also reduced. When combined with SOC, CXCL5 boosted its therapeutic effect and reduced the relevant indices of disease activity. When we correlated the effect of four different treatment groups (CXCL5, BM-MSCs, SOC, and CXCL5 plus SOC) on mice survival and target cell changes, we found that TH17 cells were the key effector cells involved in the pathogenesis of SLE.

Conclusion:

These findings demonstrated that CXCL5 dampens inflammation in the pre-clinical model of systemic lupus erythematosus via the orchestral effect of regulating neutrophil trafficking and suppressing helper T cell-mediated immune response. Administrating exogenous CXCL5 might be an attractive option to treat patients with lupus.

References:

[1]Ji S, Guo Q, Han Y, Tan G, Luo Y, Zeng F. Mesenchymal stem cell transplantation inhibits abnormal activation of Akt/GSK3beta signaling pathway in T cells from systemic lupus erythematosus mice.Cell Physiol Biochem.2012;29(5-6):705-712.

[2]Peng SL. Altered T and B lymphocyte signaling pathways in lupus.Autoimmun Rev.2009;8(3):179-183.

[3]Ferucci ED, Johnston JM, Gaddy JR, et al. Prevalence and incidence of systemic lupus erythematosus in a population-based registry of American Indian and Alaska Native people, 2007-2009.Arthritis Rheumatol.2014;66(9):2494-2502.

[4]Jakes RW, Bae SC, Louthrenoo W, Mok CC, Navarra SV, Kwon N. Systematic review of the epidemiology of systemic lupus erythematosus in the Asia-Pacific region: prevalence, incidence, clinical features, and mortality.Arthritis Care Res (Hoboken).2012;64(2):159-168.

[5]Sattwika PD, Mustafa R, Paramaiswari A, Herningtyas EH. Stem cells for lupus nephritis: a concise review of current knowledge.Lupus.2018;27(12):1881-1897.

Acknowledgments:

The work was supported by SMART II Centre Grant (NMRC/CG/M011/2017_SGH) and SingHealth Foundation (SHF/FG638P/2016).

Disclosure of Interests:

None declared

FRI0328 PROFILING OF THE IMMUNE COMPARTMENT IN THE TISSUE ENVIRONMENT OF PSORIATIC ARTHRITIS USING RNASEQ

Background:

Psoriasis is a chronic inflammatory disease of the skin with a reported prevalence of 0.09-11.4% of the population (1). 1 in 4 psoriasis patients also have psoriatic arthritis (PsA) (2), with additional joint involvement that can be associated with significant morbidity. Despite its relative commonness, the aetiology of psoriasis is not well understood, and there is no cure for this disease. Additionally, up to 30% of PsA patients with active disease are recalcitrant to treatment. Thus it remains a prerogative to understand the immune mechanisms contributing to the development of the disease in order to inform strategies for novel therapies.

Objectives:

Our aim was to identify perturbations in local tissue immune networks that could contribute to the pathology of psoriasis and psoriatic arthritis. We hypothesise that psoriasis is driven by a disrupted tissue microenvironment, which then provides cues to a susceptible peripheral immune system to drive pathology. Thus as the first part of our study, we investigated the transcriptional profiles of normal and lesional skin.

Methods:

Skin punch biopsies were obtained from both lesional and morphologically normal skin of 4 PsA patients with active disease. CD45+ cells were isolated using magnetic enrichment for RNA purification and subsequent RNAseq. Differently expressed genes (DEG) were identified and pathway analysis performed using the integrated Differential Expression and Pathway (iDEP) analysis tool. Gene set enrichment analysis was performed using GSEA.

Results:

Transcriptomic analyses of skin revealed that lesional skin, compared to non-lesional sites, was enhanced for expression of genes associated with immune processes (including genes such as such asIL17A,FCN1, andCTLA4) anti-microbial responses (such asDEF4BAandS100A8) and immune cell chemotaxis (notablyCXCL13andSELPLG), suggesting a possible inflammatory response to skin microbiota. Interestingly, lesional skin showed a deficiency in expression of genes associated with tRNA metabolic processes (includingAARS,YARS, and other aminoacyl tRNA synthetases), suggesting a possible defect in protein translation. Similarly, pathway analysis revealed an enrichment in humoral immune response pathways in PsA lesional skin, and a comparative deficiency in RNA metabolic pathways.

Conclusion:

Our transcriptional approach provides a comprehensive overview of localised immunity in psoriasis and predicts intimate interactions with the peripheral immune system. Further studies are ongoing to uncover cell types involved, as well as parallels at other disease sites (joints). These findings will facilitate the identification of novel targets for treatment of PsA.

References:

[1]World Health Organization (2016).Global report on psoriasis. [Online] (https://apps.who.int/iris/bitstream/handle/10665/204417/9789241565189_eng.pdf.psoriasis;jsessionid=54912784D28C9F36ECCD45471AC5775B?sequence=1,accessed 24 January 2020)

[2]Alinaghi F., Calov M., Kristensen L.E., Gladman D.D, Coates L.C., Julien D., Gottlieb A.B., Gisondi P., Wu J.J., Thyssen J.P., Egeberg A. (2019) Prevalence of psoriatic arthritis in patients with psoriasis: A systemic review and meta-analysis of observational and clinical studies.Journal of the American Academy of Dermatology.,80(1), 251-265.

Disclosure of Interests:

Gladys Ang: None declared, Pavanish Kumar: None declared, Dianyan Guo: None declared, Ahmad Lajam: None declared, Warren Fong Consultant of: Abbvie, Janssen, Novartis, Speakers bureau: Abbvie, Janssen, Novartis, Ying Ying Leung Speakers bureau: Novartis, Janssen, Eli Lilly, Salvatore Albani: None declared

Necrosulfonamide (NSA) protects intervertebral disc degeneration via necroptosis and apoptosis inhibition

OBJECTIVE

Previous studies have shown that nucleus pulposus (NP) cell death plays an extremely important role in the progress of intervertebral disc degeneration (IVDD). This research aimed to investigate the protective effect of the MLKL inhibitor necrosulfonamide (NSA) on human NP cells.

PATIENTS AND METHODS

We collected human NP tissues from the patients undergoing disc herniation operations and isolated NP cell from the samples. IL-1β (10 ng/ml) was used to establish a NP cells degenerated model. We analyzed the expression of caspase 3, caspase 8, RIPK1, RIPK 3, and MLKL in different degree of degenerate disc tissues. Cell viability was analyzed by the Cell Counting Kit-8 (CCK-8) assay. The expression levels of collagen Ⅱ, β-galactosidase (β-gal), caspase 3, caspase 8, RIPK1, RIPK 3, and MLKL, several inflammatory and anti-oxidant enzymes of different NP cell treat groups were detected by Western blotting, immunofluorescence staining, or RT-PCR. Flow cytometry was used to measure the ROS level and cell apoptosis.

RESULTS

The data showed that expression of caspase 3, caspase 8, RIPK1, RIPK 3, and MLKL markedly increased in severely degenerated disc tissues. IL-1β promoted the cell death of NP cells, while NSA could reverse the effects of IL-1β. We found that NAS increased the antioxidant SOD1, SOD2, CAT, and GPX3 expression and suppressed oxidative stress in the disc. Moreover, MMP3, MMP10, IL-6, and TNF-α were significantly suppressed by the NSA.

CONCLUSIONS

These results suggest that NSA prevented NP degradation via inhibiting apoptosis and necroptosis of NP cells. Besides, the protective function of antagonizing cell death may owe to the inflammation and oxidative stress suppression.

Plasma exchange combining with plasma bilirubin adsorption effectively removes toxic substances and improves liver functions of hepatic failure patients

OBJECTIVE

Hepatic failure (HF) is a kind of complex disease characterizing with liver dysfunction and a few clinical complications. Artificial liver support system (ALSS) has been applied to HF patients to improve dysfunctional liver in recent years. This study aims to evaluate therapeutic effects of ALSS approaches, including plasma exchange (PE), plasma diafiltration (PDF) and plasma bilirubin adsorption (PBA), on liver function of HF patients.

PATIENTS AND METHODS

This study is a retrospective analysis involving 516 patients diagnosed as HF between February 2014 and February 2015. Patients were randomly divided into PE, PDF, PE plus PBA, and PDF plus PBA group. Meanwhile, single-drug group and combined-drug group were also divided. The liver functions, capability of removing toxic substances and coagulation functions were evaluated both pre-treatment and post-treatment. The side effects and hospital improvement rate were also observed post-treatment.

RESULTS

Hospital improvement rate achieves to 69.6%. TBIL levels and MELD scores were significantly decreased post-treatment compared to pre-treatment (p<0.05). PTA values were significantly increased post-treatment compared to pre-treatment (p<0.05). Reduction value in PE+PBA group was significantly higher compared to PE and PDF group (p=0.002, 0.002, respectively). MELD scores were significantly decreased post-treatment compared to pre-treatment in each group (p<0.05). Combined-drug treatment is superior to single-drug treatment for removing toxic substances and improving liver functions. PE treatment, PDF treatment and PE+PBA treatment induced more side effects compared to PDF+PBA treatment.

CONCLUSIONS

PE combining with PBA plays a better role in removing toxic substances, improving liver functions of HF patients.

Impact of surgical approach on short-term oncological outcomes and recovery following low anterior resection for rectal cancer

AIM

The aim was to evaluate the influence of operative approach for low anterior resection (LAR) on oncological and postoperative outcomes. Minimally invasive surgical approaches are increasingly used for the treatment of rectal cancer with mixed outcomes.

METHOD

We compared patients undergoing LAR in the National Cancer Database between 2010 and 2015 by surgical approach. Multivariable regression was used to identify risk factors associated with conversion rate, prolonged length of stay (LOS) and 30-day unplanned readmission.

RESULTS

During the study period, 41 282 patients underwent LAR: 6035 robotic-assisted (RLAR) (14.6%), 13 826 laparoscopic (LLAR) (33.5%) and 21 421 open (OLAR) (51.9%). In propensity score matched analysis, RLAR compared to LLAR was associated with shorter LOS (6.3 vs 6.8 days, P < 0.0001), lower risk of prolonged LOS (22.1% vs 25.6%, P < 0.0001) and lower rate of conversion to open (7.5% vs 14.95%, P < 0.0001). Compared to OLAR, RLAR had shorter LOS (6.3 vs 7.8 days, P < 0.0001) and less prolonged LOS (14.1% vs. 20.9%, P < 0.0001). In multivariable analysis, for conversion to open, the laparoscopic approach was one of the risk factors; for prolonged LOS, conversion to open and non-robotic approaches (i.e. LLAR and OLAR) were risk factors; and for unplanned 30-day readmission, conversions and prolonged LOS were risk factors.

CONCLUSIONS

For patients with rectal cancer, RLAR shows recovery benefits over both open and laparoscopic LAR with reduced conversion to open compared with LLAR and less prolonged LOS compared with LLAR and OLAR. RLAR is associated with short-term oncological outcomes comparable to OLAR, supporting its use in minimally invasive surgery for rectal cancer.