The mitochondrial RNA granule modulates manganese-dependent cell toxicity

Prolonged manganese exposure causes manganism, a neurodegenerative movement disorder. The identity of adaptive and nonadaptive cellular processes targeted by manganese remains mostly unexplored. Here we study mechanisms engaged by manganese in genetic cellular models known to increase susceptibility to manganese exposure, the plasma membrane manganese efflux transporter SLC30A10 and the mitochondrial Parkinson's gene PARK2. We found that SLC30A10 and PARK2 mutations as well as manganese exposure compromised the mitochondrial RNA granule composition and function, resulting in disruption of mitochondrial transcript processing. These RNA granule defects led to impaired assembly and function of the mitochondrial respiratory chain. Notably, cells that survived a cytotoxic manganese challenge had impaired RNA granule function, thus suggesting that this granule phenotype was adaptive. CRISPR gene editing of subunits of the mitochondrial RNA granule, FASTKD2 or DHX30, as well as pharmacological inhibition of mitochondrial transcription-translation, were protective rather than deleterious for survival of cells acutely exposed to manganese. Similarly, adult Drosophila mutants with defects in the mitochondrial RNA granule component scully were safeguarded from manganese-induced mortality. We conclude that impairment of the mitochondrial RNA granule function is a protective mechanism for acute manganese toxicity.

Effects of betaine supplementation on reproductive performance of breeding geese

1. An experiment feeding three concentrations of betaine was conducted using breeding geese to analyse the reproductive performance, serum biochemical indexes, egg quality and intestinal immunity.2. A total of 450 female and 90 male Jiangnan White breeding geese were divided into three treatments, with five pen replicates each containing 30 female geese and 6 male geese.3. The results showed that there was no significant effect on the reproductive performance, serum biochemical indexes or jejunal villi goblet cells of geese with different levels of betaine in the diet (P>0.05). Compared with the control group, the addition of 2.5 g/kg betaine to the diet showed a tendency to increase egg mass (P>0.05) the betaine content in the yolk (P<0.05). Feeding betaine significantly increased the height of jejunal villi and egg yolk total cholesterol content in female geese (P<0.05).4. In conclusion, adding betaine to the goose diet was effective in its ability to improve intestinal structures and increase egg production. Adding 2.5 g/kg betaine to feed significantly increased the content of TCHOL and betaine in goose eggs.

[Coronary CT angiography derived fractional flow reserve: view from radiologist]

The diagnosis of coronary artery disease depends on a comprehensive assessment including morphological and functional information. Coronary CT angiography derived fractional flow reserve (CT-FFR) could obtain morphological and functional information from a single coronary CT angiography (CCTA) scan, achieving a "one-stop" assessment of coronary artery disease. CT-FFR is a non-invasive imaging examination to assess the hemodynamic changes of focal coronary lesions and suitable for patients with moderate to severe coronary artery stenosis or mild coronary artery stenosis combined with other high-risk characteristics, to assist in determining whether the lesions cause myocardial ischemia, and to guide clinical decisions and predict the risk of cardiovascular events. The application of CT-FFR relies on satisfied image quality of CCTA, and requires the cooperation of radiologists, clinicians and patients. This paper describes from the aspects of the measurement and analysis of CT-FFR, the diagnostic value of CT-FFR, the value of CT-FFR in assisting clinical decision making and prognosis, the comparison of CT-FFR with other functional cardiovascular imaging techniques and the future perspectives.

Covalent Organic Frameworks-TpPa-1 as an Emerging Platform for Electrochemical Sensing

Covalent organic frameworks (COFs) are a new type of metal-free porous architecture with a well-designed pore structure and high stability. Here an efficient electrochemical sensing platform was demonstrated based on COFs TpPa-1 constructed by 1,3,5-triformylphloroglucinol (Tp) with p-phenylenediamine (Pa-1), which possesses abundant nitrogen and oxo-functionalities. COFs TpPa-1 exhibited good water dispersibility and strong adsorption affinities for Pd²⁺ and thus was used as loading support to modify Pd²⁺. The Pd²⁺-modified COFs TpPa-1 electrode (Pd²⁺/COFs) showed high electrocatalytic activity for both hydrazine oxidation reaction and nitrophenol reduction reaction. In addition, TpPa-1-derived nitrogen-doped carbon presented high activity for the electro-oxidation of reduced glutathione (GSH), and sensitive electrochemical detection of GSH was achieved. The presented COFs TpPa-1 can be utilized as a precursor as well as support for anchoring electro-active molecules and nanoparticles, which will be useful for electrochemical sensing and electrocatalysis.

NOMOGRAM COMBINING PREOPERATIVE ULTRASONOGRAPHY WITH CLINICAL FEATURES FOR PREDICTING LYMPH NODES POSTERIOR TO THE RIGHT RECURRENT LARYNGEAL NERVE METASTASIS IN PATIENTS WITH PAPILLARY THYROID CANCER

Aim

To establish a nomogram combining preoperative ultrasonic and clinical features for predicting lymph nodes posterior to the right recurrent laryngeal nerve (LN-prRLN) metastasis in papillary thyroid carcinoma (PTC) patients.

Methods

Preoperative ultrasonic and clinical variables of patients with PTC from 2014 to 2021 were retrospectively analyzed. The risk factors associated with LN-prRLN metastasis were identified and validated through a developed nomogram model based on univariate and multivariate logistic regression analysis.

Results

A total of 615 patients (690 lesions) were enrolled for the training dataset and 207 patients (226 lesions) for the validation dataset with 54 (6.57%) patients developing LN-prRLN metastasis. Multivariate logistic regression analysis demonstrated that the preoperative ultrasound measurement of larger tumors (≥20 mm), higher TI-RADS category (category 5), and higher thyroglobulin level (9.86 ng/mL) in patients with PTC were predictive factors for LN-prRLN metastasis. The nomogram model was established and verified yielding a relatively good predictive performance in the training and validation dataset (AUC: 0.868 vs. 0.851).

Conclusions

The nomogram combining preoperative ultrasonography with clinical features in this study is highly predictive of LN-prRLN metastasis in patients with PTC, which may provide more personalized recommendations for clinicians in preoperative decision-making for complete dissection of LN-prRLN.

[Characteristics of the immune microenvironment and related treatment strategies in patients with periprosthetic joint infection]

Periprosthetic joint infection (PJI) involves complex immunomodulatory interactions between pathogens,biomaterials,and hosts,and correlates with alterations in the ratio of immune cells as well as in the concentration of immune checkpoint molecules.Prosthesis,biofilm,microorganisms,and host constitute a special and complex immune microenvironment.Fully studying the characteristics of immune microenvironment and potential targets of immunotherapy in orthopedic implant-associated infections are expected to provide a new direction for clinical treatment of PJI. An overview of the literature related to PJI and immune regulation at domestic and international sites was conducted to summarize and analyze the characteristics of the immune microenvironment and the potential value of related immunotherapy, aiming to provide new insights for the targeted treatment of PJI.

The influence of soil acidification on N2O emissions derived from fungal and bacterial denitrification using dual isotopocule mapping and acetylene inhibition

Denitrification, as both origins and sinks of N₂O, occurs extensively, and is of critical importance for regulating N₂O emissions in acidified soils. However, whether soil acidification stimulates N₂O emissions, and if so for what reason contributes to stimulate the emissions is uncertain and how the N₂O fractions from fungal (f_fD) and bacterial (f_bD) denitrification change with soil pH is unclear. Thus, a pH gradient (6.2, 7.1, 8.7) was set via manipulating cropland soils (initial pH 8.7) in North China to illustrate the effect of soil acidification on fungal and bacterial denitrification after the addition of KNO₃ and glucose. For source partitioning, we used and compared SP/δ¹⁸O mapping approach (SP/δ¹⁸O MAP) and acetylene inhibition technique combined isotope two endmember mixing model (AIT-IEM). The results showed significantly higher N₂O emissions in the acidified soils (pH 6.2 and pH 7.1) compared with the initial soil (pH 8.7). The cumulative N₂O emissions during the whole incubation period (15 days) ranged from 7.1 mg N kg^-1 for pH 8.7-18.9 mg N kg^-1 for pH 6.2. With the addition of glucose, relative to treatments without glucose, this emission also increased with the decrement of pH values, and were significantly stimulated. Similarly, the highest N₂O emissions and N₂O/(N₂O + N₂) ratios (rN₂O) were observed in the pH 6.2 treatment. But the difference was the highest cumulative N₂O + N₂ emissions, which were recorded in the pH 7.1 treatment based on SP/δ¹⁸O MAP. Based on both approaches, f_fD values slightly increased with the acidification of soil, and bacterial denitrification was the dominant pathway in all treatments. The SP/δ¹⁸O MAP data indicated that both the rN₂O and f_fD were lower compared to AIT-IEM. It has been known for long that low pH may lead to high rN₂O of denitrification and f_fD, but our documentation of a pervasive pH-control of rN₂O and f_fD by utilizing combined SP/δ¹⁸O MAP and AIT-IEM is new. The results of the evaluated N₂O emissions by acidified soils are finely explained by high rN₂O and enhanced f_fD. We argue that soil pH management should be high on the agenda for mitigating N₂O emissions in the future, particularly for regions where long-term excessive nitrogen fertilizer is likely to acidify the soils.

[Efficacy comparison and safety analysis of subcutaneous specific immunotherapy with standardized house dust mite allergen in patients with single and multiple allergic rhinitis]

Objective: To investigate the efficacy and safety of house dust mite (HDM) allergen subcutaneous specific immunotherapy (SCIT) in patients with allergic rhinitis (AR) with single dust mite allergy and multiple allergen allergy. Methods: A retrospective study was conducted. A total of 372 patients with allergic rhinitis induced by house dust mite were diagnosed in the allergy clinic of General Hospital of North Theater Command from January 2013 to January 2018.They were treated with house dust mite allergen preparation for standardized SCIT for 3 years or more, and had complete follow-up data. The age ranged from 5 to 55 years, the median age was 13 years, and the average age was (19.4±14.7) years; 216 males and 156 females. According to their age, they were divided into the older group (age >14 years) and younger group (age ≤ 14 years). According to the number of allergens, they were divided into single group (only HDM group allergic to house dust mites) and multi recombination (including 2 or more allergens including house dust mites). The multi recombination was further divided into HDM+1 group, HDM+2 group, HDM+3 group, HDM+4 and above group. Before treatment (T0), 1 year (T1) and 3 years (T2) after SCIT treatment, the patients in each group established files, analyzed and compared the average total nasal symptoms score (TNSS), total non nasal symptoms score (TNNSS), visual analogue scale (VAS), total medicine score (TMS) and rhinoconjunctivitis quality of life questionnaire (RQLQ), and evaluated the clinical efficacy of the treatment and the comparison of various scores in the efficacy of SCIT with different allergens and ages. Record the occurrence of local and systemic adverse reactions of all patients during treatment, and evaluate the safety of SCIT. All scores are measurement data that do not conform to normal distribution. Mann-Whitney U and Kruskai-Wallis test of independent samples are used for inter group comparison, and Bonferroni correction is used for further pairwise comparison; Chi square test and continuity correction method were used for the comparison between count data groups such as the incidence of adverse reactions and the effective rate of TNSS, and a-division method was used for further pairwise comparison. Results: After SCIT treatment, the scores of TNSS, TNNSS, TMS, VAS and RQLQ in T1 and T2 were significantly lower than those in T0, and the scores in T2 were significantly lower than those in T1 (Z=-11.168, -4.786, -6.639, -13.012, -10.652 in T0 vs T1; Z=-13.527, -8.746, -13.397, -14.477, -11.833 in T0 vs T2; Z=-4.721, -4.607, -10.020, -7.180, -5.721 in T1 vs T2; P<0.05). In T1 and T2, compared with the older group, the scores of TNSS, TNNSS, TMS, VAS and RQLQ in younger group were lower, and the differences of various indexes were statistically significant(the median scores of T1: M_younger=3.0, 1.0, 2.0, 4.0, 2.6, M_older=5.0, 2.0, 3.0, 5.0, 3.2; the median scores of T2: M_younger=3.0, 1.0, 0, 2.0, 1.3, M_older=4.0, 1.0, 1.5, 3.0, 2.3; Z_T1=-4.525, -5.830, -4.061, -3.608, -2.785; Z_T2=-3.847, -4.055, -2.820, -2.998, -3.418; P<0.05). In T1 and T2, the scores of TNSS, VAS and RQLQ in a single group after SCIT treatment were lower than those in multiple recombination(the median scores of T1:M_single=4.0, 4.0, 2.6, M_multiple=5.0, 5.0, 3.2; the median scores of T2: M_single=3.0, 2.0, 1.4, M_multiple=4.0, 3.0, 2.1), and the difference was statistically significant (Z_T1=-3.002, -2.092, -1.977; Z_T2=-3.354, -2.469, -2.116; P<0.05). There was no significant difference in TMS (the median score during T1 period: M_single=2.0, M_multiple=3.0, Z_T1=-1.130; the median score during T2 period: M_single=1.0, M_multiple=1.0, Z_T2=-1.544; P>0.05). Further comparison within the group showed that there was no significant difference in the improvement rate of TNSS during T2 period among HDM group, HDM+1 group, HDM+2 group and HDM+3 group (HDM vs HDM+1 group χ²=0.277, HDM vs HDM+2 group χ²=0.78, HDM vs HDM+3 group χ²=0.075, HDM+1 vs HDM+2 group χ²=0.057, HDM+1 vs HDM+3 group χ²=0.019, HDM+2 vs HDM+3 group χ²=0.003; P>0.005), the improvement rates were 92.5%, 90.3%, 89.1% and 89.5%. Respectively in HDM group,HDM+1 group, HDM+2 group, HDM+3 group, compared with HDM+4 and above group, the difference was statistically significant (χ²=26.144, 13.254, 15.144, 8.808; P<0.005). The improvement rate of TNSS in HDM+4 and above group was 60.9%. 122 patients had local adverse reactions during the treatment of SCIT, accounting for 32.8%. The local adverse reactions were 759 injections (15 336 injections in total), accounting for 4.95%. Most of them were swelling, dizziness, induration and pruritus at the injection site, which could be relieved by oral antihistamines or within 2 hours. There were 2 cases of local urticaria, once for each case. The symptoms were relieved within 1 week after oral antihistamine. No serious systemic adverse reactions occurred. Conclusion: Standardized SCIT may be a safe and effective treatment for AR patients, and the type of allergen may be one of the important factors affecting the efficacy of SCIT. The efficacy of SCIT was significant in AR patients with three or less allergens other than house dust mite.

POS0450 TEMPORAL MIGRATION OF IMMUNE CELLS FROM PSORIATIC SKIN TO JOINTS INITIATING SYNOVIAL INFLAMMATION IN PSORIATIC ARTHRITIS

Background

Spreading of inflammation from skin to joint is a key question behind the pathogenesis of psoriatic arthritis (PsA). Psoriasis (PsO), being one of the most prevalent skin diseases, usually anticipates joint manifestations, suggesting spreading of skin to joint disease, which happens in about 30% of the patients with psoriasis.1 To date, it is still obscure why the inflammatory process in some patients with PsO remains restrained to the skin, whereas in other patients it extents to tendons and joints.

Objectives

Using a pre-clinical model of PsA, we aimed to unveil the skin-joint axis, i.e. the spreading of psoriatic inflammation from the skin to the joints.

Methods

KAEDE transgenic mice expressing a photo-convertible fluorescent reporter were used to assess cell trafficking from inflamed skin to other organs in the mouse model of IL-23 overexpression (IL-23OE) induced PsA. Psoriatic skin lesions were irradiated with UV light to trigger the photoswitch from KAEDEGREEN to KAEDERED. Migration to different organs was determined by flow cytometry. Imaging flow cytometry was used to characterize the type of cells migrating from the skin to the joints. Migrating cells were further characterized by single-cell RNA-sequencing (scRNAseq) and functional analyses.

Results

MRI imaging and histological evaluation of IL-23OE mice revealed skin inflammation preceding joint inflammation in both wild-type and KAEDE-transgenic mice. Specific leukocyte migration from the skin to the joints started shortly after the onset of skin inflammation and before onset of inflammation within the joints of KAEDE transgenic mice. No migration was observed in healthy control animals. Other organs such as spleen or lymph nodes showed no model-dependent migration. Imaging flow cytometry revealed that the cells migrating to the joints were predominantly CD45+ CD11b+ cells. ScRNAseq analysis of sorted KAEDERED cells from inflamed joints confirmed that approximately 80% of the migrating cells were macrophages. Differential gene expression and pathway analysis revealed an imbalance between pro- and anti-inflammatory macrophages in the joints of experimental psoriatic arthritis.

Conclusion

We describe IL-23-mediated migration of skin-derived macrophages from the skin to the joints during the onset of experimental psoriatic arthritis. This process may explain the spreading from psoriatic skin to joint disease as these cells foster the development by local cytokine production once arrived in the joints.

References

[1]Veale, D.J. & Fearon, U. The pathogenesis of psoriatic arthritis. Lancet391, 2273-2284 (2018).

Disclosure of Interests

None declared.

AB0113 A MINIMAL-INVASIVE METHOD TO RETRIEVE AND IDENTIFY ENTHESEAL TISSUE FROM PSORIATIC ARTHRITIS PATIENTS

Background

Enthesitis represents a hallmark feature of spondyloarthritis, including psoriatic arthritis (PsA).1 So far, most of the data on enthesitis in PsA are based on clinical assessment of tenderness as well as MRI or ultrasound examinations.2 These approaches, however, do not allow molecular analysis of entheses, which will require acquisition of entheseal tissue. Up today, it is unknown, which entheseal structure in humans would qualify for a feasible biopsy and how correct sampling of entheseal structures could be ascertained within such biopsy material. These technical challenges have led to substantial lack of knowledge on human entheseal tissues.

Objectives

To establish a minimally invasive biopsy technique of human entheses for the analysis of entheseal tissue in patients with PsA.

Methods

Human cadavers were used for establishing the technique to retrieve tissue from the lateral humeral epicondyle enthesis (cadaveric biopsies). After biopsy, the entire entheses was surgically resected (cadaveric resections). Biopsies and resections were assessed by label-free second-harmonic-generation (SHG) microscopy. The same biopsy technique was then applied in PsA patients with subsequent definition of entheseal tissue by SHG.

Results

Entheseal biopsies were performed in five cadavers and allowed the retrieval of entheseal tissue, validated by analysis of the resection material. Thus, microscopy of biopsy and resection sections allowed differentiation of entheseal, tendon and muscle tissue by SHG and definition of specific intensity thresholds for entheseal tissue. The same method was then successfully applied to 10 PsA patients. Hence, the fraction of entheseal tissue within the PsA biopsy specimens was high (65%) and comparable to the fraction retrieved in cadaveric biospies (68%) as assessed by SHG microscopy.

Conclusion

Entheseal biopsy of the tendon plate of the lateral epicondyle is feasible in PsA patients allowing reliable retrieval of entheseal tissue and its identification by SHG microscopy.

References

[1]Schett, G, Lories D, D´Agostino MA, Elewaut E, Kirkham B, Soriano ER, McGonagle D. Enthesitis: from pathophysiology to treatment Nat Rev Rheumatol 2017 Nov 21;13(12):731-741.

[2]Groves C, Chandramohan M, Chew NS, et al. Clinical Examination, Ultrasound and MRI Imaging of The Painful Elbow in Psoriatic Arthritis and Rheumatoid Arthritis: Which is Better, Ultrasound or MR, for Imaging Enthesitis? Rheumatol Ther 2017;4:71-84.

Disclosure of Interests

None declared

POS0200 POST-mRNA VACCINE FLARES IN AUTOIMMUNE INFLAMMATORY RHEUMATIC DISEASES: INTERIM RESULTS FROM THE CORONAVIRUS NATIONAL VACCINE REGISTRY FOR IMMUNE DISEASES SINGAPORE (CONVIN-SING)

Background

Published data suggest no increased rate of flare of autoimmune inflammatory rheumatic diseases (AIIRD) after COVID-19 mRNA vaccination; however, the studies are limited by small sample size, short follow up or at risk of selection bias (voluntary physician reports or patient surveys).

Objectives

To study flares of AIIRD within three months of the first dose of an anti-SARS-COV2 mRNA vaccine.

Methods

A retrospective cohort study of consecutive AIIRD patients ≥ 12 years old, across six public hospitals in Singapore who received at least one dose of an mRNA (Pfizer/BioNTech or Moderna) vaccine. Data were censored at the first post-vaccine clinic visit when the patient had flared or if ≥ three months had elapsed since the first dose of the vaccine, whichever came first. Predictors of flare were determined by Cox proportional hazards analysis and time to flare was examined using a Nelson Aalen cumulative hazard estimate (Figure 1).

Figure 1.

Nelson-Aalen curve of flares over time

Results

2339 patients (74% Chinese, 72% female) of median (IQR) age 64 (53, 71) years were included in the interim analysis (Table 1). 2112 (90%) had the Pfizer/BioNTech vaccine and 195 (8%) had Moderna, with a median (IQR) interval of 21 (21, 23) days between the two doses. The most common AIIRD diagnoses were Rheumatoid arthritis (1063, 45%), Psoriatic arthritis (296, 12.6%) and Systemic lupus erythematosus (SLE) (288, 12.3%). 186 (8%) were treated with biologics/ targeted disease modifying agents. 2125 (91%) patients were in low disease activity or remission. Treatment was interrupted for vaccination in only 18 (0.8%) patients. Seven (0.3%) patients had previous COVID-19 infection.

Table 1.

Patient characteristics

Baseline characteristicsNo flares(n = 1887, %)Flares within 0—3 months of 1st vaccine dose (n= 272, %)Flares outside of 0 – 3 months after 1st vaccine dose (n = 180, %)Age (median years, IQR)64 (53, 71)61 (50, 69)65 (55, 71)RaceChinese1386 (73)206 (76)129 (72)Malay193 (10)28 (10)20 (11)Indian195 (10)27 (10)26 (14)GenderFemale1367 (72)200 (74)117 (65)Vaccine typePfizer/BioNTech1713 (92)239 (90)160 (90)Moderna149 (8)28 (10)18 (10)DiagnosisRheumatoid Arthritis831 (44)139 (51)93 (52)Systemic Lupus Erythematosus269 (14)20 (7)9 (5)Psoriatic Arthritis225 (12)42 (15)29 (16)Spondyloarthropathies141 (7)21 (7)17 (9)Sjogren’s Syndrome114 (6)15 (6)8 (4)Systemic sclerosis94 (5)4 (1)6 (3)Baseline Physician Disease ActivityRemission1007 (53)99 (36)63 (35)Low Disease Activity731 (39)128 (47)97 (54)Moderate Disease Activity134 (7)40 (15)20 (11)High Disease Activity15 (1)5 (2)0

452 (19%) flares were recorded during 9798.8 patient-months [4.6/100 patient-months, median (IQR) follow up duration 4.2 (3.3, 5.3) months], of which 272 (11.6%) patients flared within the 3-month period of interest and 180 (7.7%) flared outside of the 3-month period (Table 1). Median (IQR) time-to-flare was 40.5 (18, 56.6) days. 60 (22.1%) were mild and self-limiting, 170 (62.5%) were mild-moderate and 42 (15.4%) were severe. 190 (69.8%) of those who flared required escalation of treatment and 15 (5.5%) required hospital admission. 239 (10.2%) had improved disease activity after the vaccine.

On multivariate Cox regression analysis, patients in the oldest age tertile [median (IQR) 74 (71, 79) years] were less likely to flare [HR 0.80 (95% CI 0.63, 1.00), p = 0.05] Patients with inflammatory arthritis (compared with connective tissue disease, vasculitis and others) and patients with baseline active disease were more likely to flare [HR 1.72 (95% CI 1.35, 2.20), p < 0.001 and 1.82 (95% CI 1.39, 2.39), p < 0.001 respectively]

Conclusion

There was a moderately high rate of AIIRD flares after mRNA vaccination; however, there was no clustering of flares in the immediate post-vaccine period to suggest causality. Older patients were less likely to flare, while those with inflammatory arthritis and active disease at baseline were more likely to flare.

Disclosure of Interests

Margaret Ma Grant/research support from: Support grant from multiple companies for the Singapore Biologics registry, Amelia Santosa Speakers bureau: Amgen Talk, Consultant of: Pfizer ad board, Kok Ooi Kong: None declared, Chuanhui Xu: None declared, Johnston Tang Gin Xiang: None declared, Gim Gee Teng Speakers bureau: Boehringer Ingleheim, Anselm Mak Speakers bureau: J&J and GSK, Grant/research support from: GSK - the supported studies programme, Sen Hee Tay: None declared, Victoria Wei Wen Ng: None declared, Joshua Zhi En Koh: None declared, Warren Fong Speakers bureau: speaker for Abbvie, DKSH, GSK, Novartis, Li-Ching Chew Speakers bureau: pfizer and Abbvie, Consultant of: Pfizer and Abbvie Advisory Board meeting, Grant/research support from: Abbvie educational grant for ultrasound conference, Andrea Low Speakers bureau: Boehringer Ingeilheim, Consultant of: Consultant/steering group committee for BI and J&J, annie law: None declared, Yih Jia Poh: None declared, Siaw Ing Yeo Grant/research support from: Multiple pharmaceutical companies for the support of the National Biologics Registry, Ying Ying Leung Speakers bureau: Abbvie, DKSH, Jassen, Novartis and Pfizer, Wei-Rui Goh: None declared, Chuah Tyng Yu: None declared, Nur Emillia Roslan: None declared, Stanley Angkodjojo Speakers bureau: Boehringer Ingeilheim, Consultant of: Abbvie and DKSH, Kee Fong Phang: None declared, Thaschawee Arkachaisri: None declared, Melonie Sriranganathan: None declared, Teck Choon TAN: None declared, Peter Cheung Consultant of: Ad board for Boehringer Ingleheim, novartis, janssen and abbvie, Grant/research support from: Novartis, Manjari Lahiri Speakers bureau: J&J, DSKH, Consultant of: DSKH, Gilead, Grant/research support from: Multiple pharma companies contributed to the Singapore Biologics registry

Novartis

Axin2+ PDL Cells Directly Contribute to New Alveolar Bone Formation in Response to Orthodontic Tension Force

Wnt-β-catenin signaling plays a key role in orthodontic tooth movement (OTM), a common clinical practice for malocclusion correction. However, its targeted periodontal ligament (PDL) progenitor cells remain largely unclear. In this study, we first showed a synchronized increase in Wnt-β-catenin levels and Axin2+ PDL progenitor cell numbers during OTM using immunostaining of β-catenin in wild-type mice and X-gal staining in the Axin2-LacZ knock-in line. Next, we demonstrated time-dependent increases in Axin2+ PDL progenitors and their progeny cell numbers within PDL and alveolar bones during OTM using a one-time tamoxifen-induced Axin2 tracing line (Axin2CreERT2/+; R26RtdTomato/+). Coimmunostaining images displayed both early and late bone markers (such as RUNX2 and DMP1) in the Axin2Lin PDL cells. Conversely, ablation of Axin2+ PDL cells via one-time tamoxifen-induced diphtheria toxin subunit A (DTA) led to a drastic decrease in osteogenic activity (as reflected by alkaline phosphatase) in PDL and alveolar bone. There was also a decrease in new bone mass and a significant reduction in the mineral apposition rate on both the control side (to a moderate degree) and the OTM side (to a severe degree). Thus, we conclude that the Axin2+ PDL cells (the Wnt-targeted key cells) are highly sensitive to orthodontic tension force and play a critical role in OTM-induced PDL expansion and alveolar bone formation. Future drug development targeting the Axin2+ PDL progenitor cells may accelerate alveolar bone formation during orthodontic treatment.

Dietary amylose and amylopectin ratio changes starch digestion and intestinal microbiota diversity in goslings

1. Research has confirmed that amylopectin (AP) is more easily digested than amylose (AM) because AP polymers have more intramolecular hydrogen bonds and less surface area. Studying the relationship between the amylose:amylopectin (AM:AP) ratio and intestine digestion in goslings can provide useful information for effective utilisation of starch.2. A total of 288 healthy male Jiangnan White Goslings, aged three days old, were randomly allotted to four groups, which included six pen replicates per treatment with 12 goslings per replicate. Four diets were formulated with maize, long-grained rice and glutinous rice as starch sources, with AM:AP ratios of 0.12, 0.23, 0.34, and 0.45. In vitro starch digestion of the four diets was measured, as well as the effect of AM:AP ratio on growth performance, serum amino-acid concentration and intestinal microbiota diversity of goslings.3. In terms of in vitro starch digestion, the increase in dietary AM:AP ratio resulted in a decrease followed by an increase in both rapidly and slowly digestible starch. The glucose release rate at an AM:AP ratio of 0.34 showed a steady upward trend.4. The in vivo study showed that increasing the AM:AP ratio resulted in a quadratic increase in body weight (BW) and average daily feed intake (ADFI; P<0.05). Goslings fed diets with an AM:AP ratio of 0.34 had lower (P<0.05) histidine and valine serum concentrations compared with the other three starch sources. Higher AM was beneficial to jejunal microbial and diversity. The species colonisation level of the jejunum microbiota samples at an AM:AP ratio of 0.34 was higher than that in the other groups.5. The results indicated that diets with an AM:AP ratio of 0.34 improved the growth performance and intestinal microbiota diversity of goslings. This may have been due to the higher level of resistant starch in amylose, which resulted in a slow release of intestinal glucose that acted as a substrate for the microbial species, thus providing conditions that were more conducive to growth.

Cross-tissue immune cell analysis reveals tissue-specific features in humans

Despite their crucial role in health and disease, our knowledge of immune cells within human tissues remains limited. We surveyed the immune compartment of 16 tissues from 12 adult donors by single-cell RNA sequencing and VDJ sequencing generating a dataset of ~360,000 cells. To systematically resolve immune cell heterogeneity across tissues, we developed CellTypist, a machine learning tool for rapid and precise cell type annotation. Using this approach, combined with detailed curation, we determined the tissue distribution of finely phenotyped immune cell types, revealing hitherto unappreciated tissue-specific features and clonal architecture of T and B cells. Our multitissue approach lays the foundation for identifying highly resolved immune cell types by leveraging a common reference dataset, tissue-integrated expression analysis, and antigen receptor sequencing.

Computational design of mechanically coupled axle-rotor protein assemblies

Natural molecular machines contain protein components that undergo motion relative to each other. Designing such mechanically constrained nanoscale protein architectures with internal degrees of freedom is an outstanding challenge for computational protein design. Here we explore the de novo construction of protein machinery from designed axle and rotor components with internal cyclic or dihedral symmetry. We find that the axle-rotor systems assemble in vitro and in vivo as designed. Using cryo-electron microscopy, we find that these systems populate conformationally variable relative orientations reflecting the symmetry of the coupled components and the computationally designed interface energy landscape. These mechanical systems with internal degrees of freedom are a step toward the design of genetically encodable nanomachines.

[Predictive values of serum 8-hydroxydeoxyguanosine on disease progression and prognosis of patients with sepsis]

Objective: To investigate the values of serum 8-hydroxydeoxyguanosine (8-OHdG) in predicting disease progression and prognosis of patients with sepsis. Methods: The prospective observational research methods were used. A total of 124 patients with sepsis who met the inclusion criteria were admitted to the Department of Emergency of the First Affiliated Hospital of Wenzhou Medical University from April 2015 to July 2016, including 79 males and 45 females, aged (62±15) years. The sepsis-related organ failure assessment (SOFA) scores of all patients on admission and on the second day of admission and their difference (ΔSOFA) were calculated. The patients were divided into non-progression group with ΔSOFA score <2 (n=101) and progression group with ΔSOFA score ≥2 (n=23), and according to the survival during hospitalization, the patients were divided into survival group (n=85) and death group (n=39). Data of patients between non-progression group and progression group, survival group and death group were compared, including the gender, age, days in emergency intensive care unit (ICU), smoking, hypertension, diabetes mellitus, serum white blood cell count, serum C-reactive protein, and serum procalcitonin on admission, and serum 8-OHdG within 24 h of admission. The multivariate logistic regression analysis was used to screen the independent risk factors of disease progression and death during hospitalization in 124 patients with sepsis, the receiver's operating characteristic (ROC) curves were drawn according to the independent risk factors, and the area under the curve (AUC), the best threshold, and the sensitivity and specificity under the best threshold were calculated. The patients were divided into high 8-OHdG group (n=35) and low 8-OHdG group (n=89) according to the best threshold in ROC curve of death during hospitalization. The data including the gender, age, SOFA score on admission, SOFA score on the second day of admission, and ΔSOFA score of patients in the two groups were compared. The survival rates of patients within 90 d of admission in the two groups were compared by the Kaplan-Meier method. Data were statistically analyzed with independent sample t test, Mann-Whitney U test, chi-square test, and Log-rank test. Results: The gender, age, days in emergency ICU, smoking, complicated with hypertension, complicated with diabetes mellitus, serum white blood cell count, serum C-reactive protein, and serum procalcitonin on admission of patients in non-progression group and progression group were similar (P>0.05). The serum 8-OHdG within 24 h of admission of patients in progression group was significantly higher than that in non-progression group (Z=-2.31, P<0.05). Multivariate logistic regression analysis showed that the serum 8-OHdG within 24 h of admission was the independent risk factor for disease progression of 124 patients with sepsis (odds ratio=1.06, with 95% confidence interval of 1.01-1.11, P<0.05). The AUC under the ROC curve of serum 8-OHdG within 24 h of admission to predict disease progression of 124 patients with sepsis was 0.65 (with 95% confidence interval of 0.52-0.79, P<0.05), the optimal threshold was 32.88 ng/mL, and the sensitivity and specificity under the optimal threshold was 52.2% and 79.2%, respectively. The gender, age, days in emergency ICU, smoking, complicated with hypertension, complicated with diabetes mellitus, and serum white blood cell count, serum C-reactive protein, and serum procalcitonin on admission of patients in survival group and death group were similar (P>0.05). The serum 8-OHdG within 24 h of admission of patients in death group was significantly higher than that in survival group (Z=-2.37, P<0.05). Multivariate logistic regression analysis showed that the serum 8-OHdG within 24 h of admission was the independent risk factor for death of 124 patients with sepsis (odd ratio=1.04, with 95% confidence interval of 1.00-1.09, P<0.05). The AUC under the ROC curve of serum 8-OHdG within 24 h of admission to predict death of patients during hospitalization was 0.63 (with 95% confidence interval of 0.52-0.75, P<0.05), the optimal threshold was 32.43 ng/mL, the sensitivity and specificity under the optimal threshold was 51.3% and 84.7%, respectively. The gender and age of patients in high 8-OHdG group and low 8-OHdG group were similar (P>0.05). The SOFA score on admission, SOFA score on the second day of admission, and ΔSOFA score of patients in high 8-OHdG group were significantly higher than those in low 8-OHdG group (with Z values of -2.49, -3.01, and -2.64, respectively, P<0.05 or P<0.01). The survival rate within 90 d of admission of patients in low 8-OHdG group was significantly higher than that in high 8-OHdG group (χ2=14.57, P<0.01). Conclusions: Serum 8-OHdG level is an independent risk factor for disease progression and death in sepsis patients with limited ability for predicting disease progression and prognosis of sepsis of patients. The patients with higher serum 8-OHdG level have higher death risk within 90 d of admission.

A Micro Electrochemical Sensor for Multi-Analyte Detection Based on Oxygenated Graphene Modified Screen-Printed Electrode

Electrode interfaces with both antibiofouling properties and electrocatalytic activity can promote the practical application of nonenzymatic electrochemical sensors in biological fluids. Compared with graphene, graphene oxide (GO) possesses unique properties such as superior solubility (hydrophilicity) in water, negative charge, and abundant oxygenated groups (oxo functionalities) in the plane and edge sites, which play an essential role in electrocatalysis and functionalization. In this work, a micro electrochemical sensor consisting of GO-modified screen-printed electrode and PDMS micro-cell was designed to achieve multi-analyte detection with excellent selectivity and anti-biofouling properties by electrochemically tuning the oxygen-containing functional species, hydrophilicity/hydrophobicity, and electrical conductivity. In particular, the presented electrodes demonstrated the potential in the analysis of biological samples in which electrodes often suffer from serious biofouling. The interaction of proteins with electrodes as well as uric acid was investigated and discussed.

A223 THE CHAIR STAND TEST IS A RELIABLE FRAILTY METRIC FOR PREDICTING WAITLIST MORBIDITY AND MORTALITY IN PATIENTS WITH CIRRHOSIS

Background

Frailty is defined as a clinical state of increased vulnerability to health and age associated stressors. The liver frailty index (LFI), composed of grip strength, chair stand and balance testing, is an accepted predictor of morbidity and mortality in cirrhosis. With the need for COVID-19 related social distancing, many appointments are being carried out virtually. The chair stand subcomponent of the LFI has the potential to be evaluated virtually, with a high reliability as compared to in-person testing noted in other disease populations.

Aims

To determine if the chair stand test is an independent predictor of morbidity and mortality in patients with cirrhosis.

Methods

822 adult patients with cirrhosis were prospectively enrolled from five centers (3 in Canada, 1 in the United States, and 1 in India). Inclusion criteria included adult patients with cirrhosis. 787 of these patients completed a chair stand test at baseline, measured as the time (seconds) a patient takes to rise from sitting with their arms folded across their chest five times (measured in-person). The times were divided into 3 categories: >15 seconds, between 10 and 15 seconds, and <10 seconds. Patients who could not complete 5 chair stands were classified in the >15 seconds category. Primary outcome was all-cause mortality. Secondary outcome was unplanned all-cause hospital admission. Fine-Gray proportional hazard regression models were used to evaluate the association between the chair stand time and the outcomes. We adjusted for baseline age, sex, and MELD score and accounted for liver transplantation as a competing risk. Cumulative incidence functions were used to create a graphical representation of the survival analysis.

Results

Patients were divided into three groups: group 1, <10 seconds (n = 276); group 2, 10–15 seconds (n = 290); and group 3, >15 seconds (n = 221). Mortality was increased in group 3 in comparison to group 1 (HR 3.21, 95% CI: 2.16–4.78, p<0.001). Similarly, the hazard of non-elective hospitalizations was higher in group 3 in comparison to group 1 (HR 2.24, 95% CI: 1.73–2.91, p<0.001). Overall, patients with chair stand times greater than 15 seconds had increased all-cause mortality (HR 2.78, 95% CI 2.01–3.83, p<0.001) and non-elective hospitalizations (HR 1.84, 95% CI 1.48–2.29, p<0.001) when compared to patients with times less than 15 seconds.

Conclusions

A time to complete 5 chair stands of >15 seconds predicts morbidity and mortality in patients with cirrhosis. This test shows promise as a frailty measure that could be evaluated over a virtual platform.

Funding Agencies

None

PERK signaling activation restores nucleus pulposus degeneration by activating autophagy under hypoxia environment

OBJECTIVES

Intervertebral disc (IVD) degeneration is an important disease with no efficient biological therapy identified. Autophagy, a wildly known therapeutic target for human disease, has been demonstrated to be activated under hypoxia, with underlying mechanism remains elusive. Thus, this study aims to specify the role of autophagy in IVD degeneration, the regulating mechanism of hypoxia-inducing autophagy, and the therapeutic value of autophagy for IVD degeneration.

METHODS

RNA-seq was used to screen the primary pathway affected in NP cells under hypoxia, the specific link between hypoxia and autophagy were investigated using ChIP-seq and dual luciferase reporter assay. Conditional ATG7 knockout mice (ATG7^-/-) were constructed for assessing the effect of autophagy on IVD degeneration, and puncture induced mice model of IVD degeneration were used for intradiscal injection to evaluate the therapeutic value of autophagy.

RESULTS

We demonstrated that hypoxia induces autophagy by transcriptional activation of autophagic gene LC3B and ATG7, which is controlled by PERK signaling. Then, we observed that inhibiting autophagy or PERK signaling leads to impaired NP cell viability and function, furthermore, using ATG7 knockout (ATG7^-/-) mice, we identified the protective role of autophagy in IVD. Furthermore, we found that intradiscal injection of PERK signaling agonist, CCT020312, significantly restores the degeneration level of needle punctured mice IVD.

CONCLUSION

We showed that the activation of PERK signaling upon hypoxia serves as a vital mechanism to induce autophagy and identified the therapeutic value of PERK signaling agonist for IVD degeneration treatment.

[Association between CD137 and ischemia-reperfusion injury in patients with acute ST-segment elevation myocardial infarction]

Objective: To explore the relationship between the levels of serum soluble CD137 (sCD137) and membrane-bound CD137 (mCD137) and the occurrence of ischemia reperfusion injury (IRI) in patients with acute ST-segment elevation myocardial infarction (STEMI). Methods: This is a cross-sectional study. Consecutive patients with acute STEMI, who underwent emergency percutaneous coronary intervention (PCI) in the Department of Cardiology, Jiangsu University Affiliated Hospital from May 2019 to September 2020, were enrolled. According to the absence or presence of IRI, patients were divided into IRI group and non-IRI group. Clinical data of the two groups were collected and compared. sCD137 level was detected by enzyme linked immunosorbent assay. Ficoll density gradient centrifugation was used to separate peripheral blood mononuclear cells (PBMC) and RNA was extracted, mCD137 mRNA expression level was detected by PCR. Serum sCD137 levels and the mCD137 mRNA levels of PBMC before, after PCI and 24 hours after PCI were compared. The correlation between serum sCD137 level, PBMC mCD137 mRNA level and clinical indicators was observed. The univariate and multivariate logistic binary regression analyses were performed to evaluate the related risk factors of IRI. ROC curve was used to analyze the predictive value of defined parameters for IRI. Results: A total of 112 STEMI patients were enrolled. There were 42 cases (of which 33 were males (78.6%), mean age was (58.6±12.7) years) in non-IRI group and 70 cases(of which 56 were males (80.0%), mean age was (64.5±11.6) years) in IRI group. Compared with the non-IRI group, patients in the IRI group had longer hospital stays, older age, lower rates of obesity, lower systolic and diastolic blood pressure at admission, higher proportion of the the right coronary artery as culprit vessel, lower rate of the use of angiotensin-converting enzyme inhibitor/angiotensin-Ⅱ receptor blocker/angiotensin receptor neprilysin inhibitor, higher levels of urea nitrogen and creatinine, lower glomerular filtration rate, lower triglycerides, higher D-dimer and B-type natriuretic peptide_max, higher proportion of Killip grade Ⅳ and cardiovascular adverse events (all P<0.05). sCD137 levels at the preoperative, postoperative and 24 hours after surgery were significantly higher in the IRI group than in the non-IRI group, while the mRNA levels of CD137 was similar between the two groups. The level of sCD137 in patients after PCI was lower than that before operation, the level of mCD137 mRNA was higher than that before operation (P<0.05). Serum sCD137 levels were positively correlated with hospitalization days, age, B-type natriuretic peptide, creatinine, ischemic time, C Reactive protein (CRP) and CRP/albumin (P<0.05), and negatively correlated with body mass index, glomerular filtration rate and albumin (P<0.05). The mCD137 mRNA expression level of PBMC was positively correlated with hospital stay, age, B-type natriuretic peptide, ischemic time, CRP and CRP/albumin (P<0.05), and negatively correlated with body mass index, glomerular filtration rate, albumin (P<0.05). Multivariate logistic regression analysis showed that higher sCD137 (OR=1.038, 95%CI: 1.009-1.069), aspartate aminotransferase, (OR=1.029, 95%CI: 1.009-1.050) and lower albumin (OR=0.829, 95%CI: 0.703-0.829) before surgery were independent risk factors of IRI (P<0.05). Receiver operating characteristic curve showed that the area under the curve of sCD137 was 0.672 (95%CI: 0.574-0.770, P=0.002) for the prediction of IRI, the best cut-off value was 28.43×10^-3 μg/L with sensitivity of 95.2% and specificity of 48.6%. Conclusion: The significantly increased level of sCD137 in acute STEMI patients is positively correlated with reperfusion injury, which is an independent risk factor of IRI and may be related to the prognosis of patients with IRI.

Distinguishing N2O and N2 ratio and their microbial source in soil fertilized for vegetable production using a stable isotope method

Vegetable production systems with excessive nitrogen fertilizer result in severe N₂O emission. It is pivotal to identify the source of N₂O for reducing N₂O emission, but estimating microbial pathways of N₂O production is very difficult due to the existence of N₂O reduction. A promising tool can address this problem by using δ¹⁸O and δ¹⁵N^SP of N₂O to construct a dual isotopocule plot. For ascertaining the microbial pathways of N₂O production and consumption in soil fertilized for vegetable production, four treatments were set up: urea (U), half urea and half organic fertilizer (UO), organic fertilizer (O) and no fertilizer (NF), and the experiment was carried out continuously for two years. The δ¹⁸O vs. δ¹⁵N^SP plot method indicated that the nitrification/fungal denitrification was a dominant in N₂O emission, and the U treatment was the highest, followed by OU, O and NF in the both years. Among the different treatments, furthermore, the N₂O flux had the same trend, whereas the extent of N₂O reduction showed an opposite trend. Overall, inorganic fertilizer enhances nitrification/fungal denitrification and hinders reduction of N₂O to N₂, resulting in a larger amount of N₂O emission. However, organic fertilizer increases the contribution of denitrification and greatly improves the extent of N₂O reduction, which helps to reduce N₂O emission. Therefore, organic fertilizer is crucial to reducing N₂O emission by enhancing N₂O reduction and should be properly applied in production practice.