Epistasis facilitates functional evolution in an ancient transcription factor

A protein's genetic architecture - the set of causal rules by which its sequence produces its functions - also determines its possible evolutionary trajectories. Prior research has proposed that the genetic architecture of proteins is very complex, with pervasive epistatic interactions that constrain evolution and make function difficult to predict from sequence. Most of this work has analyzed only the direct paths between two proteins of interest - excluding the vast majority of possible genotypes and evolutionary trajectories - and has considered only a single protein function, leaving unaddressed the genetic architecture of functional specificity and its impact on the evolution of new functions. Here, we develop a new method based on ordinal logistic regression to directly characterize the global genetic determinants of multiple protein functions from 20-state combinatorial deep mutational scanning (DMS) experiments. We use it to dissect the genetic architecture and evolution of a transcription factor's specificity for DNA, using data from a combinatorial DMS of an ancient steroid hormone receptor's capacity to activate transcription from two biologically relevant DNA elements. We show that the genetic architecture of DNA recognition consists of a dense set of main and pairwise effects that involve virtually every possible amino acid state in the protein-DNA interface, but higher-order epistasis plays only a tiny role. Pairwise interactions enlarge the set of functional sequences and are the primary determinants of specificity for different DNA elements. They also massively expand the number of opportunities for single-residue mutations to switch specificity from one DNA target to another. By bringing variants with different functions close together in sequence space, pairwise epistasis therefore facilitates rather than constrains the evolution of new functions.

The simplicity of protein sequence-function relationships

How complicated is the genetic architecture of proteins - the set of causal effects by which sequence determines function? High-order epistatic interactions among residues are thought to be pervasive, making a protein's function difficult to predict or understand from its sequence. Most studies, however, used methods that overestimate epistasis, because they analyze genetic architecture relative to a designated reference sequence - causing measurement noise and small local idiosyncrasies to propagate into pervasive high-order interactions - or have not effectively accounted for global nonlinearity in the sequence-function relationship. Here we present a new reference-free method that jointly estimates global nonlinearity and specific epistatic interactions across a protein's entire genotype-phenotype map. This method yields a maximally efficient explanation of a protein's genetic architecture and is more robust than existing methods to measurement noise, partial sampling, and model misspecification. We reanalyze 20 combinatorial mutagenesis experiments from a diverse set of proteins and find that additive and pairwise effects, along with a simple nonlinearity to account for limited dynamic range, explain a median of 96% of total variance in measured phenotypes (and >92% in every case). Only a tiny fraction of genotypes are strongly affected by third- or higher-order epistasis. Genetic architecture is also sparse: the number of terms required to explain the vast majority of variance is smaller than the number of genotypes by many orders of magnitude. The sequence-function relationship in most proteins is therefore far simpler than previously thought, opening the way for new and tractable approaches to characterize it.

Catalytic ozonation of methylethylketone over porous Mn-Cu/HZSM-5

The catalytic ozonation of methylethylketone (MEK) was performed at the room temperature (25 °C) using the synthesized Mn and Cu-loaded zeolite (ZSM-5, SiO₂/Al₂O₃ = 80) catalysts. The ZSM-5 zeolite was used as a porous support material due to the large surface area and high capacity for adsorption of volatile organic compounds. Since Mn and Cu-loaded zeolite catalysts were effective for the catalytic ozonation of VOCs such as MEK, according to the loaded concentration of Mn and Cu, there are four types of metal loaded ZSM5 catalysts synthesized [5 wt% Mn/ZSM-5, 5 wt% Cu/ZSM-5, 5 wt% Mn-1 wt% Cu/ZSM-5 (5Mn1CuZSM), and 5 wt% Cu-1 wt% Mn/ZSM-5]. The catalytic efficiency for the removal of MEK and ozonation using the different catalysts was also studied. Based on various experimental analysis processes, the characteristics of the synthesized catalysts were explored and the removal efficiencies of MEK and O₃ together with the CO_x concentration generated from the destruction of MEK and O₃ were explored. The results for the decomposition of MEK and O₃ at the room temperature indicated that the Mn dominant ZSM-5 catalysts showed better efficiency for the conversion of MEK and O₃. The 5 wt% Mn/ZSM-5 outweighed the rest of them for the removal of MEK while the 5Mn1CuZSM showed the best catalytic reactivity for the conversion of O₃ and the CO₂ selectivity. It was ascertained that during the reaction time of catalyst and reactants of 120 min the Mn dominantly deposited bimetallic catalyst, 5Mn1CuZSM, was determined as the most effective for the removal of MEK and O₃ due to the high capability of production of Mn³⁺ species and more available adsorbed oxygen sites compared to the other catalysts. Finally, the durability measurement for the 5Mn1CuZSM catalyst was performed together with the produced CO and CO₂ concentration for 420 min.

Recurrent neural networks for dynamical systems: Applications to ordinary differential equations, collective motion, and hydrological modeling

Classical methods of solving spatiotemporal dynamical systems include statistical approaches such as autoregressive integrated moving average, which assume linear and stationary relationships between systems' previous outputs. Development and implementation of linear methods are relatively simple, but they often do not capture non-linear relationships in the data. Thus, artificial neural networks (ANNs) are receiving attention from researchers in analyzing and forecasting dynamical systems. Recurrent neural networks (RNNs), derived from feed-forward ANNs, use internal memory to process variable-length sequences of inputs. This allows RNNs to be applicable for finding solutions for a vast variety of problems in spatiotemporal dynamical systems. Thus, in this paper, we utilize RNNs to treat some specific issues associated with dynamical systems. Specifically, we analyze the performance of RNNs applied to three tasks: reconstruction of correct Lorenz solutions for a system with a formulation error, reconstruction of corrupted collective motion trajectories, and forecasting of streamflow time series possessing spikes, representing three fields, namely, ordinary differential equations, collective motion, and hydrological modeling, respectively. We train and test RNNs uniquely in each task to demonstrate the broad applicability of RNNs in the reconstruction and forecasting the dynamics of dynamical systems.

Search for 70 μeV Dark Photon Dark Matter with a Dielectrically Loaded Multiwavelength Microwave Cavity

Microwave cavities have been deployed to search for bosonic dark matter candidates with masses of a few μeV. However, the sensitivity of these cavity detectors is limited by their volume, and the traditionally employed half-wavelength cavities suffer from a significant volume reduction at higher masses. Axion dark matter experiment (ADMX)-Orpheus mitigates this issue by operating a tunable, dielectrically loaded cavity at a higher-order mode, which allows the detection volume to remain large. The ADMX-Orpheus inaugural run excludes dark photon dark matter with kinetic mixing angle χ>10^{-13} between 65.5  μeV (15.8  GHz) and 69.3  μeV (16.8  GHz), marking the highest-frequency tunable microwave cavity dark matter search to date.

Effects of early recurrence and extra-PV triggers on long-term recurrence after catheter ablation for atrial fibrillation

Background

Although early recurrence (ER) within 3 months after atrial fibrillation (AF) catheter ablation (AFCA) was recently reported to be a reliable predictor of late recurrence (LR), the mechanism is not clear.

Purpose

We explored the characteristics of patients with ER and compared the long-term late recurrence (LR) pattern depending on the existence of extra-pulmonary vein trigger (ExPV-trigger).

Methods

Among 3643 patients who underwent de novo AFCA, we included 1249 patients (59.2±11.0 years old, 31.3% persistent AF) who underwent isoproterenol provocation and regular follow-up over three years after AFCA. We evaluated the risk factors for ER and compared the patients with ER alone (10.1%), LR alone (16.6%), and ER+LR (15.9%), and the outcome of repeat procedure.

Results

Overall ER (ER alone and ER+LR) was independently associated with persistent AF (OR 1.58 [1.16–2.14], p=0.003), extra-PV triggers (OR 2.80 [1.90–4.13], p<0.001), and empirical extra-PV ablation (OR 1.54 [1.15–2.07], p=0.004). Overall LR (LR alone and ER+LR) risk was significantly higher in the ER with ExPV-trigger group than in ER without ExPV-trigger or no ER groups (Log-rank p<0.001). The rhythm outcome of the second procedure did not differ between ER+LR and LR alone groups (Log-rank p=0.160), but was worse in the ER+LR ExPV-trigger than in ER+LR without ExPV-trigger or LR alone groups (Log-rank p=0.005).

Conclusion

ER was independently associated with LR after de novo AFCA. ExPV-trigger played crucial roles in ER and LR after de novo AFCA and worse rhythm outcome after redo AFCA.

Funding Acknowledgement

Type of funding sources: None.

External validation of the biomarker based ABCD score in atrial fibrillation patients with a non gender CHA2DS2 VASc score 0 to 1, A Korean multicenter retrospective cohort

Background

Patients with low to intermediate risk atrial fibrillation (AF), defined as non-gender CHA2DS2-VASc score of 0–1, are still at risk of stroke. This study verified the usefulness of ABCD score (Age [≥60 years], B-type natriuretic peptide [BNP] or N-terminal pro-BNP [≥300 pg/ml], Creatinine clearance [<50 ml/min/1.73 m2], and Dimension of the left atrium [≥45 mm]) for stroke risk stratification in non-gender CHA2DS2-VASc score 0–1.

Methods

This multi-center cohort study retrospectively analyzed AF patients with non-gender CHA2DS2-VASc score 0–1. The primary endpoint was the incidence of stroke with or without anti-thrombotic treatment (ATT). An ABCD score was also validated.

Results

Overall, 2694 patients (56.3±9.5 years; female, 726 [26.9%]) were followed-up for 4.0±2.8 years. The overall stroke rate was 0.84/100 person-years (P-Y), stratified as follows: 0.46/100P-Y for an ABCD score 0; 1.02/100P-Y for an ABCD score≥1. The ABCD score was superior to the non-gender CHA2DS2-VASc score in stroke risk stratification (C-index=0.618, P=0.015; net reclassification improvement=0.576, P=0.040; integrated differential improvement=0.033, P=0.066). ATT was prescribed in 2353 patients (86.5%), and the stroke rate was significantly lower in patients receiving non-vitamin K antagonist oral anticoagulant (NOAC) therapy and an ABCD score≥1 than in those without ATT (0.44/100P-Y versus 1.55/100 P-Y; hazard ratio=0.26, 95% confidence interval 0.11–0.63, P=0.003).

Conclusion

The biomarker-based ABCD score demonstrated improved stroke risk stratification in AF patients with non-gender CHA2DS2-VASc score 0–1. Furthermore, NOAC with an ABCD score≥1 was associated with significantly lower stroke rate in AF patients with a non-gender CHA2DS2-VASc score 0–1.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Korean Disease Control and Prevention Agency

Electro-optic sampling based characterization of broad-band high efficiency THz-FEL

Extremely high beam-to-radiation energy conversion efficiencies can be obtained in a THz FEL using a strongly tapered helical undulator at the zero-slippage resonant condition, where a circular waveguide is used to match the radiation group velocity to the electron beam longitudinal velocity. In this paper we report on the first electro-optic sampling (EOS) based measurements of the broadband THz FEL radiation pulses emitted in this regime. The THz field waveforms are reconstructed in the spatial and temporal domains using multi-shot and single-shot EOS schemes respectively. The measurements are performed varying the input electron beam energy in the undulator providing insights on the complex dynamics in a waveguide FEL.

Regional and annual patterns in respiratory virus co-infection etiologies and antibiotic prescriptions for pediatric mycoplasma pneumoniae pneumonia

OBJECTIVE

Mycoplasma pneumoniae (M. pneumoniae) pneumonia is the second-most common cause of community-acquired pneumonia (CAP). This study aimed at investigating into the prevalence of macrolide-resistant M. pneumoniae (MRMP) with respiratory virus co-infection and the antibiotic prescriptions in children with CAP in four provinces in Korea, and to assess the variations in the findings across regions and throughout the year.

PATIENTS AND METHODS

This prospective study was conducted in 29 hospitals in Korea between July 2018 and June 2020. Among the enrolled 1,063 children with CAP, all 451 patients with M. pneumoniae underwent PCR assays of M. pneumoniae and respiratory viruses, and the presence of point mutations of residues 2063 and 2064 was evaluated.

RESULTS

Gwangju-Honam (88.6%) showed the highest prevalence of MRMP pneumonia, while Daejeon-Chungcheong (71.3%) showed the lowest, although the differences in prevalence were not significant (p=0.074). Co-infection of M. pneumoniae pneumonia and respiratory virus was observed in 206 patients (45.4%), and rhinovirus co-infection (101 children; 22.2%) was the most frequent. The prevalence of MRMP pneumonia with respiratory virus co-infection and the antibiotic prescriptions differed significantly among the four provinces (p < 0.05). The monthly rate of MRMP pneumonia cases among all cases of M. pneumoniae pneumonia and tetracycline or quinolone prescriptions did not differ significantly among the four regions (trend p > 0.05) during the study period.

CONCLUSIONS

The prevalence of M. pneumoniae pneumonia with virus co-infection and antibiotic prescriptions could differ according to region, although the MRMP pneumonia rate showed no difference within Korea.

POS0030 CLINICAL AND GENETIC FACTORS ASSOCIATED WITH RADIOGRAPHIC PROGRESSION IN PATIENTS WITH ANKYLOSING SPONDYLITIS

Background

Ankylosing spondylitis (AS) is a heritable inflammatory disease eventually leading to spinal fusion 1. Severity of structural damage is highly variable, some patients develop almost no change in spinal structure for long disease duration, whereas others have total ankylosis even in the early stage of disease.

Objectives

To identify clinical and genetic factors associated with severe radiographic damage in patients with AS.

Methods

We newly generated genome-wide variant data (833K, KoreanChip) of 444 AS patients. The severity of radiographic damage was assessed using the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS). To identify clinical and genetic factors associated with severe radiographic damage, multiple linear regression analyses were performed. Human AS osteoprogenitor cells were used for functional validation. Pathway analysis was also conducted.

Results

A total 444 AS patients (male 90.3%) were enrolled. The median mSASSS at baseline was 7.7 (5.5-16.8). The patients were observed for 9.6 (7.9-11.3) years. Within this period, the median mSASSS score increased to 14.0 (7.0-36.8). The most influential clinical factor of final mSASSS was baseline mSASSS (β = 0.818, p < 0.001). Peripheral joint involvement was associated with decreased possibility of severe radiographic damage (β = -0.221, p < 0.001). Eye involvement, longer follow up duration, and increased age at enrollment were associated with increased final mSASSS (β = 0.165, p < 0.001; β = 0.039, p < 0.001; β = 0.010, p = 0.002, respectively). Ryanodine receptor 3 (RYR3) gene was associated with severe radiographic damage (β = 1.105, p = 1.97x10-06). Treatment with Rhodamine B, a ligand of RYR3, induced extracellular matrix mineralization of AS osteoprogenitors in vitro. For the pathway analysis, PI3K-Akt signaling pathway and focal adhesion pathway were associated with severe radiographic damage in AS.

Conclusion

This study identified clinical and genetic factors that contributed to better understanding of the pathogenesis and biology associated with radiographic damage in AS.

References

[1]Li Z, Brown MA. Progress of genome-wide association studies of ankylosing spondylitis. Clinical & Translational Immunology. 2017;6(12):e163.

Disclosure of Interests

None declared

Epistatic drift causes gradual decay of predictability in protein evolution

Epistatic interactions can make the outcomes of evolution unpredictable, but no comprehensive data are available on the extent and temporal dynamics of changes in the effects of mutations as protein sequences evolve. Here, we use phylogenetic deep mutational scanning to measure the functional effect of every possible amino acid mutation in a series of ancestral and extant steroid receptor DNA binding domains. Across 700 million years of evolution, epistatic interactions caused the effects of most mutations to become decorrelated from their initial effects and their windows of evolutionary accessibility to open and close transiently. Most effects changed gradually and without bias at rates that were largely constant across time, indicating a neutral process caused by many weak epistatic interactions. Our findings show that protein sequences drift inexorably into contingency and unpredictability, but that the process is statistically predictable, given sufficient phylogenetic and experimental data.

COVID-19 susceptibility and clinical outcomes in autoimmune inflammatory rheumatic diseases (AIRDs): a systematic review and meta-analysis

OBJECTIVE

This meta-analysis aims to assess the susceptibility to and clinical outcomes of COVID-19 in autoimmune inflammatory rheumatic disease (AIRD) and following AIRD drug use.

MATERIALS AND METHODS

We included observational and case-controlled studies assessing susceptibility and clinical outcomes of COVID-19 in patients with AIRD as well as the clinical outcomes of COVID-19 with or without use of steroids and conventional synthetic disease-modifying antirheumatic drugs (csDMARDs).

RESULTS

Meta-analysis including three studies showed that patients with AIRD are not more susceptible to COVID-19 compared to patients without AIRD or the general population (OR: 1.11, 95% CI: 0.58 to 2.14). Incidence of severe outcomes of COVID-19 (OR: 1.34, 95% CI: 0.76 to 2.35) and COVID-19 related death (OR: 1.21, 95% CI: 0.68 to 2.16) also did not show significant difference. The clinical outcomes of COVID-19 among AIRD patients with and without csDMARD or steroid showed that both use of steroid (OR: 1.69, 95% CI: 0.96 to 2.98) or csDMARD (OR: 1.35, 95% CI: 0.63 to 3.08) had no effect on clinical outcomes of COVID-19.

CONCLUSIONS

AIRD does not increase susceptibility to COVID-19, not affecting the clinical outcome of COVID-19. Similarly, the use of steroids or csDMARDs for AIRD does not worsen the clinical outcome.

Molecular and structural basis of olfactory sensory neuron axon coalescence by Kirrel receptors

Projections from sensory neurons of olfactory systems coalesce into glomeruli in the brain. The Kirrel receptors are believed to homodimerize via their ectodomains and help separate sensory neuron axons into Kirrel2- or Kirrel3-expressing glomeruli. Here, we present the crystal structures of homodimeric Kirrel receptors and show that the closely related Kirrel2 and Kirrel3 have evolved specific sets of polar and hydrophobic interactions, respectively, disallowing heterodimerization while preserving homodimerization, likely resulting in proper segregation and coalescence of Kirrel-expressing axons into glomeruli. We show that the dimerization interface at the N-terminal immunoglobulin (IG) domains is necessary and sufficient to create homodimers and fail to find evidence for a secondary interaction site in Kirrel ectodomains. Furthermore, we show that abolishing dimerization of Kirrel3 in vivo leads to improper formation of glomeruli in the mouse accessory olfactory bulb as observed in Kirrel3-/- animals. Our results provide evidence for Kirrel3 homodimerization controlling axonal coalescence.

Re-evaluation of the prognostic significance of oropharyngeal dysphagia in idiopathic inflammatory myopathies

OBJECTIVE

To investigate the prognostic significance of videofluorographic swallowing study (VFSS)-confirmed oropharyngeal dysphagia in idiopathic inflammatory myopathies (IIMs).

METHOD

We reviewed the medical records of patients who were diagnosed with IIM between 2009 and 2020 at Seoul St Mary's Hospital. All oropharyngeal dysphagia cases were limited to VFSS-confirmed dysphagia found during the initial diagnostic work-up for IIM. We described the findings on VFSS and the course of the dysphagic symptoms. Logistic regression and survival analyses were performed to evaluate the risk of pneumonia and mortality, respectively.

RESULTS

We found 88 patients with IIM who met the criteria. Among them, 17 patients (19%) had oropharyngeal dysphagia. Except for two cases lost to follow-up and one deceased case, all of the patients with dysphagia (14 of 14) had swallowing function restored within 6 months. The risk of pneumonia within 3 months from the diagnosis of IIM was significant [odds ratio = 4.49, 95% confidence interval (CI) 1.07-18.88]. The median follow-up duration was 34 and 27 months for the groups without and with dysphagia, respectively. The survival analysis failed to demonstrate that the presence of oropharyngeal dysphagia increased the risk of death (hazard ratio = 0.77, 95% CI: 0.085-7.00).

CONCLUSIONS

Oropharyngeal dysphagia found at the initial diagnosis of IIM improved within 3-6 months in nearly all cases. Furthermore, IIM patients who had oropharyngeal dysphagia at the initial diagnosis of IIM were not likely to have shorter survival, even if the risk of pneumonia was increased in the short term.

POS0555 THE NATURAL COURSE OF RHEUMATOID ARTHRITIS-ASSOCIATED INTERSTITIAL LUNG DISEASE FOCUSING ON LUNG PHYSIOLOGY: A PROSPECTIVE OBSERVATIONAL COHORT STUDY (PART 1)

Background:

Interstitial lung disease (ILD) is a severe extra-articular manifestation of rheumatoid arthritis (RA). However, there are few prospective studies for the natural course of lung physiology in most patients with RA-ILD.

Objectives:

To assess the natural course of lung physiology of RA-ILD and the relation between arthritis activity and pulmonary physiology in patients with RA-ILD.

Methods:

The KOrean Rheumatoid Arthritis ILd (KORAIL) cohort is the prospective observational cohort and aims to investigate the natural course of RAILD. Based on either 1987 or 2020 ACR criteria, patients diagnosed with RA and ILD based on CT scan were recruited from six tertiary medical hospitals in Korea since January 2015. RA disease activity was assessed using swollen and tender joint count by treating physician, inflammatory markers including CRP and ESR, and patient’s global assessment annually. Pulmonary function tests (PFT), including FVC, FEV1, DLCO, and chest CT scan, were conducted annually.

Results:

We analyzed 163 patients at baseline (V1), 141 at 1-year (V2), 122 at 2-year (V3), and 88 at 3-year follow-up (V4). The mean (±SD) duration since RA diagnosis and since ILD diagnosis was 7.6±8.0 and 2.7±3.1 years, respectively. The female to male ratio was about 2:1, and 58.9% of patients (n=96) were 65 years old or older. Only two patients were negative for RF and anti-CCP; 98.7% of patients (n=161/163) were positive for RF (n=143, 87.7%) or anti-CCP antibody (n=154, 94.5%). At enrollment, one-hundred-nine patients (66.9%) had FVC ≥80 % of predicted. Twenty-five patients (15.3%) showed FEV1/FVC≥0.7, of which seventeen patients, only ten percent of a total cohort (10.4%), had FVC ≥80% of predicted, which corresponds to the obstructive pattern. Proportion of patients showed a ≥10-point decline from the enrollment in FVC of the predicted value were around 10% at every year (Table 1). The proportion of patients with a relative decline of ≥10% from the enrollment in FVC predicted was increased every year because of cumulation. The proportion of patients with a relative decline of ≥10% from the previous visit in FVC predicted was also around 10-15% every year. Proportions of patients with 55% or more DLco % pred. has been decreased annually; 78.5% (n=128/158) at V1, 72.9% (n=105/139) at V2, 68.7% (n=90/117) at V3, and 56.6% (n=56/85) at V4. Patients with a relative decline of ≥10% from the enrollment in DLco predicted was 38 (27.5 %) at V2 and 37 (31.9%) at V3. Patients with a relative decline of ≥10% from the previous visit in DLco predicted was 29 (25.2%) at V3. Of note, thirty patients (21.7%) showed a relative 10% or more increase from enrollment in DLco predicted at V2, and so did 30 patients (25.9%) at V3.

Table 1.

The analysis of forced vital capacity (FVC) in KORIL cohort

V1 (enrollment)V2 (1-year)V3 (2-year)V4 (3-year)FVC (mL), mean±SD2549.5 ± 743.32479.5±764.42435.8 ± 742.82405.7 ± 731.2FVC % of predicted, mean±SD84.70 ± 16.7484.7±18.184.3 ± 17.683.1 ± 19.1Rate of FVC decline, mL·year-1 (95% CI)--14 (-49, 21)-62 (-104, -21)-A 10-point decline from V1 in predicted FVC value, n (%)-10 (7.1)16 (13.3)8 (9.4)Relative decline of 10% from V1 in predicted FVC value, n (%)-17 (12.1)23 (18.9)17 (19.3)Relative decline of 10% from the previous visit in predicted FVC value, n (%)-17 (12.1)17 (14.2)13 (15.3)

Conclusion:

Annually, about 10-15% of patients experience a relative ≥10% decline from the previous visit in FVC predicted value in RA-ILD.

Acknowledgements:

This work was supported by the Korea Health Technology R&D Project through the Korea Health Industry Development Institute, funded by the Ministry of Health and Welfare, Republic of Korea (grant no.HI14C1277).

Disclosure of Interests:

None declared

POS0563 THE NATURAL COURSE OF RHEUMATOID ARTHRITIS-ASSOCIATED INTERSTITIAL LUNG DISEASE FOCUSING ON LUNG PHYSIOLOGY AND DISEASE ACTIVITY: A PROSPECTIVE COHORT STUDY (PART 2)

Background:

Interstitial lung disease (ILD) is a severe extra-articular manifestation of rheumatoid arthritis (RA). However, the effect of RA disease activity on the course of ILD is not yet known.

Objectives:

To assess the natural course of lung physiology of RA-ILD and the relation between arthritis activity and pulmonary physiology in patients with RA-ILD.

Methods:

The Korean Rheumatoid Arthritis ILd (KORAIL) cohort is the prospective observational cohort and aims to investigate the natural course of RAILD. Based on either 1987 or 2020 ACR criteria, patients diagnosed with RA and ILD based on CT scan were recruited from six tertiary medical hospitals in Korea since January 2015. RA disease activity was assessed using disease activity (DAS)28-ESR and CRP, annually. Pulmonary function tests (PFT), including FVC and DLCO were conducted annually. According to the transition of DAS28-ESR status, we classified patients into four groups: Group A. persistent remission or low disease activity, Group B. improvement, Group C. worsening, Group D. persistent moderate to high disease activity.

Results:

We analyzed 143 patients who completed a 2-year follow-up (visit 2) or had died with available PFT results at least twice. Mean duration since RA diagnosis and since ILD diagnosis was 7.6±8.0 and 2.7±3.1 years, respectively. Twenty-four patients were Group A, 33 Group B, 10 Group C and 30 Group D. The mean of FVC (mL) and % of the predicted value in FVC was significantly lower in Group D than in other groups (Table 1). The annual rate of decline in FVC was -42 (95% CI -93~10) mL·year-1 in Group B while -113 (95% CI -206~-21) mL·year-1 in Group C (Figure 1A). The annual decline rate in Group C was further exaggerated in patients with ≥ 80% of FVC predicted (-141, 95% CI -251~-32 mL·year-1). During two years of follow-up, patients ever experienced a relative decline of ≥10% from the enrollment in FVC predicted was 27.3%(n-9/33) in Group B whereas 30.0% (3/10) in Group C. The annual rate of decline in % of DLco predicted value was also the largest in Group C (-4.6 %·year-1, 95%CI -8.5~-0.7), which further exaggerated in patients with ≥ 80% of FVC predicted (-4.9%·year-1, 95 %CI -8.3~-1.5, Figure 1B). Of note, about half of patients with maintained not only low disease activity (Group A) but also moderate to severe disease activity (Group D) improved in DLco at least 10% or more from the enrollment of DLco predicted value (Group A: 54.2%, n=13/24, Group D: 46.7%, n=14/30).

Conclusion:

RA disease activity is associated with the change of lung physiology in patients with RA-ILD; worsening disease activity associated with a further decrease of annual change in FVC and maintaining low disease activity associated with a further increase of annual change in % of DLco predicted value.

Table 1.

The analysis of forced vital capacity (FVC) according to disease activity transition group.

Group AGroup BGroup CGroup DFVC (mL), mean±SD2810.0±771.12528.8±735.32801.0±952.72048.3±575.7FVC % of predicted, mean±SD87.5±14.586.5±16.693.0±15.677.2±17.3Rate of FVC decline, mL·year-1 (95% CI)-52 (-112,7)-42 (-93,10)-113 (-206, -21)1 (-52, 54)A 10-point decline from V1 in predicted FVC value, n (%)29 (20.3)6 (25.0)6 (18.2)3 (30.0)Relative decline of 10% from the enrollment in predicted FVC value, n (%)35 (24.5)5 (20.8)9 (27.3)3 (30.0)Figure 1.

The annual change of pulmonary physiology according to disease activity transition group.

Acknowledgements:

This work was supported by the Korea Health Technology R&D Project through the Korea Health Industry Development Institute, funded by the Ministry of Health and Welfare, Republic of Korea (grant no.HI14C1277).

Disclosure of Interests:

None declared

POS0564 THE EFFECT OF ARTHRITIS TREATMENT ON THE COURSE OF RHEUMATOID ARTHRITIS-ASSOCIATED INTERSTITIAL LUNG DISEASE FOCUSING ON BIOLOGIC DMARDS: FROM A PROSPECTIVE COHORT STUDY (PART 5)

Background:

Interstitial lung disease (ILD) is a severe extra-articular manifestation of rheumatoid arthritis (RA). However, the effect of RA treatment on the course of ILD is not yet known.

Objectives:

To assess the effect of RA treatment on the course of lung physiology of RA-focusing on biologic DMARDs treatment.

Methods:

The Korean Rheumatoid Arthritis ILd (KORAIL) cohort is the prospective observational cohort and aims to investigate the natural course of RAILD. Based on either 1987 or 2020 ACR criteria, patients diagnosed with RA and ILD based on CT scan were recruited from six tertiary medical hospitals in Korea since January 2015. RA disease activity was assessed using disease activity (DAS)28-ESR and CRP, annually. Pulmonary function tests (PFT), including FVC and DLCO were conducted annually. In the current study, we analyzed patients who completed a 2-years follow-up or had died during those terms till October 2020. They classified patients into three groups: patients treated with abatacept ≥24 weeks ever (Group 1), those with other bDAMRDs ≥24 weeks ever (Group 2), and those without any bDMARDs or with bDMARDs <24 weeks (Group 3).

Results:

Of a total of 125 patients who completed 2-year follow-up, 21 patients were classified as Group 1, 26 for Group 2, and 78 for Group 3. The mean age or the number of patients with ≥ 65-year-old was comparable between groups(Table 1). The mean duration since RA diagnosis was shorter in Group 3, but that since ILD diagnosis was comparable. DAS28-ESR score was comparable between Group 1 and 2 at enrollment, so was in 1-year-follow-up (p=0.75) and 2-year-follow-up (p=1.00). FVC and % of the predicted value in FVC, FEV1, and DLco were also comparable among the three groups at enrollment. The numbers of patients with ≥10-point decline in % of FVC predicted was 2 (10.0%) for Group 1, 1 (3.8%) for Group 2, 3 (3.9%) for Group3 during the first 1-year follow-up, and 3 (15.8%), 3 (11.5%), 10 (14.1%) during the last 1-year follow up. The percent of FVC predicted was 81.6 ± 17.5 %, 87.4 ± 17.9 %, 85.2 ± 17.7 % for Group 1,2 and 3, respectively, at 1-year-follow-up, and 79.5 ± 18.8 %, 89.0 ± 16.8 %, 83.5 ± 17.3 % at 2-year-follow-up. (Figure 1A). The percent of DLco predicted was 75.5 ± 23.4 %, 66.7 ± 18.1 %, 67.5 ± 16.7 % for Group 1,2 and 3, respectively, at 1-year-follow-up, and 74.0 ± 23.7 %, 69.1 ± 18.9 %, 67.0 ± 18.5 % at 1-year-follow-up (Figure 1B).

Conclusion:

Treatment of bDMARDs did not exacerbate FVC than without bDMARDs treatment and mitigated the decline of DLCO compared to without bDMARDs treatment during 2-year-follow-up.

Table 1.

Clinical characteristics at enrollment (V1)

TotalGroup 1.Group 2.Group 3.PN125212678Age at enrollment65.9±8.266.0±8.863.9±8.066.6±8.10.3465, n (%)72 (57.6)13 (61.9)11 (42.3)48 (61.5)0.21Female, n (%)89 (71.2)16 (76.2)17 (65.4)56 (71.8)0.71RA duration, years8.0±8.49.6±6.69.2±9.07.2±8.60.05ILD duration, years3.0±3.33.8±3.73.8±3.52.5±3.10.10BMI, kg/m224.1±3.123.8±3.724.8±2.923.9±3.00.39Ever-smoker1855180.57RF positive, n (%)111 (88.8)19 (90.5)22 (84.6)70 (89.7)0.72Anti-CCP positive, n (%)119 (95.2)20 (95.2)25 (96.2)74 (94.9)1.00Arthritis activityDAS28-ESR4.0 ± 1.44.1 ± 1.14.3 ± 1.83.8 ± 1.40.60*DAS28-CRP3.1 ± 1.43.2 ± 1.23.4 ± 1.63.0 ± 1.40.76*HAQ-DI0.70 ± 0.760.64 ± 0.490.82 ± 0.820.67 ± 0.800.28*Pulmonary function testFVC, ml2522.5 ± 765.42406.2 ± 772.62617.3 ± 965.22522.2 ± 692.30.65FVC, % of pred.84.6 ± 16.980.9 ± 17.786.12 ± 17.8285.08 ± 16.50.53FEV1, % of pred.92.4 ± 21.492.0 ± 24.890.6 ± 22.193.0 ± 20.40.88DLco, % of pred.71.5 ± 19.772.3 ± 26.769.1 ± 16.472.0 ± 18.70.80Figure 1.

Acknowledgements:

This research was supported by Bristol Myers Squibb Inc.

Disclosure of Interests:

Sung Hae Chang: None declared, Ji Sung Lee: None declared, Jeong Seok Lee: None declared, Chan Ho Park: None declared, Min Uk Kim: None declared, You-Jung Ha: None declared, Eun Ha Kang: None declared, Yeon Ah Lee: None declared, Yongbeom Park: None declared, Jung-Yoon Choe: None declared, Eun Young Lee Grant/research support from: Bristol Myers Squibb Inc.

Antiarrhythmic drug responders among patients with recurrent atrial fibrillation after catheter ablation

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): The Ministry of Health and Welfare The National Research Foundation of Korea (NRF)

Backgroud

Sinus rhythm (SR) can be maintained with antiarrhythmic drugs (AADs) in a considerable number of patients with recurrent atrial fibrillation (AF) after AF catheter ablation (AFCA).

Purpose

We explored the characteristics and long-term outcomes of patients who maintained clinically acceptable rhythm control with AADs for 2 years.

Methods

Among 2,935 consecutive AAD-resistant patients who underwent a de novo AFCA, we included 512 recurrent patients (73.0% men, 59.2 ± 10.5 years old, 56.4% paroxysmal AF) who were followed up for over 2 years under AAD medications.

Results

In total, 218 patients remained in SR (AAD-responders[2-yrs], 42.6%) and 294 had recurrent AF among whom, 162 underwent repeat procedures (redo-AFCA[AAD failure-2-yrs]). We also compared the AAD-responders[2-yrs] with 40 patients who underwent AFCA before AADs (redo-AFCA[Before AAD]). AAD-responders[2-yrs] were independently associated with an old age (odds ratio [OR] 1.02 [1.00-1.04] p = 0.037), paroxysmal AF (OR 1.51 [1.04-2.19] p = 0.003), and a delayed recurrence timing of &gt; 18 months (OR 1.52 [1.04-2.22] p = 0.032). When comparing the AAD-responder[2-yrs] and redo-AFCA[AAD failure-2-yrs] groups, the recurrence pattern showed a convergence after 7 years. The overall rhythm outcome was better in the redo-AFCA[Before AAD] group than AAD group (log rank p = 0.013).

Conclusion

Among the patients with recurrent AF after AFCA, over 40% remained in SR with AADs for 2 years, especially those who were old, those with a paroxysmal type, and those who had a delayed recurrence timing of &gt;18 months after the de novo procedure. UnivariateMultivariateOdds Ratio(95% CI)p valueOdds Ratio(95% CI)p valueAge1.02 (1.00-1.04)0.0231.02 (1.00-1.04)0.037Female1.64 (1.11-2.42)0.0141.29 (0.85-1.95)0.236PAF1.58 (1.11-2.26)0.0121.51 (1.04-2.19)0.030Time to recurrence after the initial AFCA &gt;18mo*1.59 (1.11-2.30)0.0131.52 (1.04-2.22)0.032LA dimension, mm0.99 (0.96-1.02)0.360LV ejection fraction, %1.03 (1.01-1.06)0.0111.02 (0.997-1.046)0.081Heart failure0.65 (0.34-1.24)0.192Hypertension1.18 (0.83-1.67)0.358Diabetes1.01 (0.65-1.71)0.844Stroke or TIA0.96 (0.56-1.66)0.879Vascular disease1.43 (0.88-2.31)0.151Logistic regression analysis for AAD responders Abstract Figure. K-M analysis of AF-free survival rate

Dark Energy Survey Year 1 Results: Cosmological Constraints from Cluster Abundances, Weak Lensing, and Galaxy Correlations

We present the first joint analysis of cluster abundances and auto or cross-correlations of three cosmic tracer fields: galaxy density, weak gravitational lensing shear, and cluster density split by optical richness. From a joint analysis (4×2pt+N) of cluster abundances, three cluster cross-correlations, and the auto correlations of the galaxy density measured from the first year data of the Dark Energy Survey, we obtain Ω_{m}=0.305_{-0.038}^{+0.055} and σ_{8}=0.783_{-0.054}^{+0.064}. This result is consistent with constraints from the DES-Y1 galaxy clustering and weak lensing two-point correlation functions for the flat νΛCDM model. Consequently, we combine cluster abundances and all two-point correlations from across all three cosmic tracer fields (6×2pt+N) and find improved constraints on cosmological parameters as well as on the cluster observable-mass scaling relation. This analysis is an important advance in both optical cluster cosmology and multiprobe analyses of upcoming wide imaging surveys.

Association between mortality risk and the number, location, and sequence of subsequent fractures in the elderly

The mortality risk showed a positive correlation as the number of subsequent fractures increased. Hip fracture showed the greatest association with mortality risk, followed by vertebral fracture. For the combination of hip and vertebral fracture, a hip fracture after a vertebral fracture showed the highest mortality risk.

INTRODUCTION

It is unclear whether subsequent fractures or a certain location and sequence of subsequent fractures are associated with mortality risk in the elderly. We aimed to investigate the relationship between subsequent fractures and mortality risk.

METHODS

Using the Korean National Health Insurance Research Database, we analyzed the cohort data of 24,756 patients aged > 60 years who sustained fractures between 2002 and 2013. Cox regression was used to assess the mortality risk associated with the number, locations, and sequences of subsequent fractures.

RESULTS

Mortality hazard ratios (HRs) for women and men were shown to be associated with the number of subsequent fractures (one, 1.63 (95% confidence interval [CI], 1.48-1.80) and 1.42 (95% CI, 1.28-1.58); two, 1.75 (95% CI, 1.47-2.08) and 2.03 (95% CI, 1.69-2.43); three or more, 2.46(95% CI, 1.92-3.15) and 1.92 (95% CI, 1.34-2.74), respectively). For women, the mortality risk was high when hip (HR, 2.49; 95% CI, 1.80-3.44) or vertebral (HR, 1.40; 95% CI, 1.03-1.90) fracture occurred as a second fracture. Compared with a single hip fracture, there was a high mortality risk in the group with hip fracture after the first vertebral fracture (HR, 2.90; 95% CI, 1.86-4.54), followed by vertebral fracture after the first hip fracture (HR, 1.90; 95% CI, 1.12-3.22).

CONCLUSION

The mortality risk showed a positive correlation as the number of subsequent fractures increased. Hip fracture showed the greatest association with mortality risk, followed by vertebral fracture. For the combination of hip and vertebral fracture, a hip fracture after a vertebral fracture showed the highest mortality risk.

Roadblock-qPCR: A simple and inexpensive strategy for targeted measurements of mRNA stability

The stability of mRNAs is fundamental to determining expression level and dynamics. Nonetheless, current approaches for measuring transcript half-lives (e.g. transcription shutoff) are generally toxic or technically complex. Here we describe an alternative strategy for targeted measurements of endogenous mRNA stability that is simple, inexpensive, and non-toxic. Cells are first metabolically labelled with the nucleoside analog 4-thiouridine (4sU). Extracted mRNA can then be treated with the thiol-reactive compound N-ethylmaleimide. This compound modifies 4sU nucleotides and sterically interferes with reverse transcription of 4sU-containing transcripts, disrupting their conversion into cDNA. The decay rate of non-4sU-containing pre-existing mRNA can then be monitored by quantitative PCR (qPCR). Importantly, this approach avoids the biochemical isolation of 4sU-labelled transcripts and/or RNA-seq analysis required for other metabolic-labelling strategies. In summary, our method combines the simplicity of "transcription shutoff" strategies with the accuracy of metabolic-labelling strategies for measurements of mRNA stability across a wide range of half-lives.

Comment on "Ancient origins of allosteric activation in a Ser-Thr kinase"

Hadzipasic et al (Reports, 21 February 2020, p. 912) used ancestral sequence reconstruction to identify historical sequence substitutions that putatively caused Aurora kinases to evolve allosteric regulation. We show that their results arise from using an implausible phylogeny and sparse sequence sampling. Addressing either problem reverses their inferences: Allostery and the amino acids that confer it were not gained during the diversification of eukaryotes but were lost in a subgroup of Fungi.

SAT0225 THE POSITIVITY FOR HISTOPATHOLOGIC ASSESSMENT IN SALIVARY GLANDS SHOWED LITTLE IMPACTS ON CLINICAL FEATURES FOR ESTABLISHED PRIMARY SJÖGREN’S SYNDROME IN A CERTAIN ETHNIC POPULATION

Background:

The presence and the severity of focal lymphocytic sialadenitis in minor salivary glands is a pathognomonic feature in primary Sjögren’s syndrome (pSS). However, it has not been determined whether performing of minor salivary gland biopsy (MSGB) in a setting of serologically and clinically established pSS give us additional clinical information.

Objectives:

To investigate the necessity of MSGB in established pSS patients with the anti-Ro/SSA antibody.

Methods:

We extracted 185 patients with anti-Ro/SSA antibody-positive pSS from the Korean Initiative of primary Sjögren’s Syndrome, a prospective cohort. We assigned them into two groups, 161 patients with focus score ≥1 and other 24 with focus score < 1. The two groups were compared in various clinical aspects including the severity of glandular dysfunctions, systemic disease activities, extra-glandular manifestations, and other clinical indices and laboratory values. We also evaluated relationship between focus score and clinically important variables in pSS.

Results:

Between two groups, there were no significant differences in the severity of secretory dysfunctions, the frequency of extra-glandular manifestations, systemic disease activities represented by various clinical indices, and laboratory findings possibly predicting the risk for lymphoma. Rather, the Sjögren’s syndrome disease damage index was higher in the group with focus score < 1. Among all variables, serum immunoglobulin G level solely showed the correlation with focus score.

Conclusion:

Given that little influence on clinical phenotypes, unconditional performing of MSGB should be reconsidered for serologically and clinically established pSS, especially in low-risk area for lymphoproliferative diseases.

Disclosure of Interests:

None declared

FRI0231 TREATMENT OF DIGITAL ULCERS IN PATIENTS WITH SYSTEMIC SCLEROSIS: PROSPECTIVE COHORT STUDY

Background:

Digital ulcer (DU) is a common clinical manifestation in patients with systemic sclerosis (SSc). About 70% of patients with SSc experience DUs during the first 10 years, which limit daily activities and may result in digital gangrene or amputation. Several vasoactive/vasodilating agents have been suggested for treatment, but few studies have compared the efficacy of those drugs.

Objectives:

The objective of our study was to compare the efficacy of medical treatment for SSc related-DUs, focusing on on endothelin receptor antagonist (ERA) and phosphodiesterase-5 inhibitors (PDE5inh).

Methods:

In this prospective observational cohort study, we recruited patients who had one or more active SSc-related DUs and newly started or changed a medical treatment for SSc-related DUs from 13 medical centers in South Korea. The primary outcome was to compare the time to resolution of cardinal DU (CU) according to the treatments. The secondary outcomes included changes in the size or number of CU and changes in the number of DUs. CU was defined as the most clinically significant DU chosen by the investigators. Patients were followed up at every 4 weeks after enrollment until 12 weeks and finally at 24 weeks.

Results:

Seventy-one patients were enrolled. Seven patients were excluded due to follow-up loss or withdrawal of consent. A total of 64 patients were analyzed. Seventy-eight percent (n=50) were female. The mean age at enrollment was 49.6 ± 11.6 year-old, and the mean disease duration was 7.1 ± 5.9 years. Twenty-eights pateitns (43.8%) were limited SSc. Forty-nine patients (n=76.6%) started ERA treatment (bosentan=49). Eleven patients (17.2%) started PDE5inh treatment (n=9 for sildenafil, n=1 for udenafil, and n=1 for tadalafil). Four patients who started medication other than ERA or PDE5inh classified as other treatment groups. Seventeen patients (26.6%) were on background calcium channel blockers (CCBs). CU healed in 25 patients (39.1%) at 12 weeks and 43 patients (67.2%) at 24 weeks. The mean time to heal CUs were 54.4 ± 22.7 days at 12 weeks and 91.6 ± 49.2 days at 24 weeks. Time to heal CU was comparable among patients on ERA, PDE5inh, and others (p=0.53, figure 1). The CU area was comparable among the three groups at baseline, 12, and 24 weeks. The mean area of CU in patients on ERA at baseline at 12, and 24 weeks was 21.3±19.4 mm2, 8.2±14.6 mm2, and 4.6±7.7 mm2, respectively. The mean area of CU in patients with PDE5inh at baseline at 12, and 24 weeks was 26.2±28.1 mm2, 3.5±3.6 mm2, and 1.3±4.3 mm2. New DUs developed in 4 patients (8.3%) in ERA, whereas 4 patients (40.0%) in PDE5inh at 4 weeks. The use of ERA was significantly associated with less new DUs development than the use of PDE5inh at 4 weeks follow-up (RR for developing new DU patients on ERA, 0.21; 95% CI 0.06-0.70; p=0.02) At 24 weeks follow-up, none of the patients on CCB developed new DUs.

Conclusion:

The time to heal CU for ERA and PDEinh users was comparable in the current study. ERA treatment was associated with reduced new DU occurrence compared with PDE5inh treatment. None of the patients with CCB treatment developed new DU development at 24 weeks.

Acknowledgments:

This study was supported by Handok Pharmaceutical Inc., Seoul, Republic of Korea.

Disclosure of Interests:

Sung Hae Chang: None declared, Jae-Bum Jun Grant/research support from: Clinical trials; Corbus, JW Pharmaceutical, Speakers bureau: SK Chemical, Yun Jong Lee: None declared, Tae Young Kang: None declared, Yongbeom Park: None declared, Seung-Geun Lee: None declared, Shin-Seok Lee: None declared, Eun Bong Lee: None declared

Figure 1

NELL2-Robo3 complex structure reveals mechanisms of receptor activation for axon guidance

Axon pathfinding is critical for nervous system development, and it is orchestrated by molecular cues that activate receptors on the axonal growth cone. Robo family receptors bind Slit guidance cues to mediate axon repulsion. In mammals, the divergent family member Robo3 does not bind Slits, but instead signals axon repulsion from its own ligand, NELL2. Conversely, canonical Robos do not mediate NELL2 signaling. Here, we present the structures of NELL-Robo3 complexes, identifying a mode of ligand engagement for Robos that is orthogonal to Slit binding. We elucidate the structural basis for differential binding between NELL and Robo family members and show that NELL2 repulsive activity is a function of its Robo3 affinity and is enhanced by ligand trimerization. Our results reveal a mechanism of oligomerization-induced Robo activation for axon guidance and shed light on Robo family member ligand binding specificity, conformational variability, divergent modes of signaling, and evolution.

Association Between Aerobic Exercise and Handgrip Strength in Adults: A Cross-Sectional Study Based on Data from the Korean National Health and Nutrition Examination Survey (2014-2017)

OBJECTIVES

Handgrip strength is an easy-to-assess indicator of overall muscle strength and can be used to evaluate health status. Although previous studies have reported an increase in grip strength due to aerobic exercise, such a study has not been conducted on Korean participants. This study aimed to investigate the effects of aerobic exercise on handgrip strength and examine the association between these two variables in Korean patients with hypertension or diabetes.

DESIGN

Cross-sectional study.

SETTING

This study used data from the 6th and 7th Korean National Health and Nutrition Examination Survey (2014-2017).

PARTICIPANTS

A total of 19,650 individuals aged ≥19 years who had responded to questionnaires concerning aerobic exercise and handgrip strength were analyzed.

MEASUREMENTS

The relationship between aerobic activity and handgrip strength was examined by logistic regression analysis.

RESULTS

The mean age of individuals in the low muscle strength group was higher than that in the normal muscle strength group. The odds ratio for low handgrip strength was higher in individuals who did not perform aerobic exercise than in those who performed aerobic exercise. Following adjustment for covariates, the odds ratios (95% confidence intervals) for low handgrip strength were 1.415 (0.187-1.688) in the total sample, 1.799 (1.376-2.352) in patients with hypertension, and 1.811 (1.208-2.715) in patients with diabetes.

CONCLUSION

The results of our study indicated a strong association between aerobic exercise and handgrip strength in the Korean population.

Molecular basis of force-from-lipids gating in the mechanosensitive channel MscS

Prokaryotic mechanosensitive (MS) channels open by sensing the physical state of the membrane. As such, lipid-protein interactions represent the defining molecular process underlying mechanotransduction. Here, we describe cryo-electron microscopy (cryo-EM) structures of the E. coli small-conductance mechanosensitive channel (MscS) in nanodiscs (ND). They reveal a novel membrane-anchoring fold that plays a significant role in channel activation and establish a new location for the lipid bilayer, shifted ~14 Å from previous consensus placements. Two types of lipid densities are explicitly observed. A phospholipid that ‘hooks’ the top of each TM2-TM3 hairpin and likely plays a role in force sensing, and a bundle of acyl chains occluding the permeation path above the L105 cuff. These observations reshape our understanding of force-from-lipids gating in MscS and highlight the key role of allosteric interactions between TM segments and phospholipids bound to key dynamic components of the channel.

Trends of sarcopenia and physical activity in elderly Koreans using KNHANES 2007-2017

Background

Sarcopenia is one of risk factors for prevalence of chronic diseases which is associated with aging. Distribution of sarcopenia in Korea is important because Korea is one of the most rapid countries in population aging. This study aimed to understand trends in PA in elderly Koreans (≥65 years of age) and identify the proportion of sarcopenia in elderly Koreans based on a reference cutoff value of handgrip strength (28.6kg for men and 16.4kg for women).

Methods

This study was performed using data from Korea National Health and Nutrition Examination Survey (KNHANES) between 2007-2017. Physical activity on walking (2007-2017), aerobic exercise (2014-2017), and muscle strength (2007-2017) were analyzed to understand trends of physical activity participation in elderly Koreans. Furthermore, using handgrip strength data from KNHANES (2014-2017), the study examined how sarcopenia has distributed in elderly in Korea.

Results

The proportion of elderly Koreans engaged in walking decreased from 46.8% (age standardized) in 2007 to 35.7% in 2017, and the proportion of elderly Koreans engaged in aerobic exercise decreased 41.1% in 2014 to 29.4% in 2017. Even though, the proportion of elderly Koreans engaged in muscle strength increased from 11.6% in 2007 to 17.5% in 2017, the proportion of sarcopenia in elderly men increased from 22.6% in 2014 to 29.3% in 2017 and the proportion of sarcopenia in elderly women increased from 19.3% in 2014 to 30.1% in 2017.

Conclusions

During the past 10 years, the participation in muscle strength has increased, while the participation in walking and aerobic exercise has decreased in elderly Koreans. Nevertheless, the proportion of sarcopenia in elderly Koreans has increased. This analysis provides evidence of necessity of public health efforts to implement sarcopenia reduction interventions and examine the correlation between sarcopenia and physical activity pattern in elderly Koreans.

Key messages

Although the participation of physical activity has decreased, the participation of muscle strength has increased in elderly Koreans (≥65 years of age). The increased proportion of sarcopenia in elderly Koreans showed the necessity of new public health intervention to reduce sarcopenia in spite of growing trends of muscle strength in elderly Koreans.

Relationship between airway obstruction and C-reactive protein levels in a community-based population of Korea

OBJECTIVE: To examine the relationship between high-sensitivity C-reactive protein (hs-CRP) levels and lung function in a community-based cohort of South Korea.DESIGN: The Ansung-Ansan cohort database (an ongoing prospective study of a community-based population) was used in the analysis. We defined airway obstruction as the ratio between forced expiratory volume in 1 sec:forced vital capacity ratio (FEV1:FVC) of <95% of the predicted value for a healthy person. We also used the serum level of hs-CRP as a marker of inflammation. Multivariate analysis was performed with adjustment for the clinical characteristics of the participants.RESULTS: A total of 5528 individuals were eligible for the study. The average age was 55.1 years, and 47.8% were males. The prevalence of airway obstruction was 9.0%, and the mean hs-CRP level was 1.51 mg/dl. Serum hs-CRP levels increased with the severity of airway obstruction, and the latter worsened with an increase in the hs-CRP level. In multivariate analysis, as the hs-CRP level increased, FEV1 and FVC decreased. A higher FEV1:FVC ratio was associated with lower hs-CRP levels in males.CONCLUSION: Higher hs-CRP levels were associated with decreased FEV1 and FVC in a general population of Korea. The FEV1:FVC ratio decreased with an increase in the hs-CRP level in males.

Treatment of glioblastoma using multicomponent silica nanoparticles

Glioblastomas (GBMs) remain highly lethal. This partially stems from the presence of brain tumor initiating cells (BTICs), a highly plastic cellular subpopulation that is resistant to current therapies. In addition to resistance, the blood-brain barrier limits the penetration of most drugs into GBMs. To effectively deliver a BTIC-specific inhibitor to brain tumors, we developed a multicomponent nanoparticle, termed Fe@MSN, which contains a mesoporous silica shell and an iron oxide core. Fibronectin-targeting ligands directed the nanoparticle to the near-perivascular areas of GBM. After Fe@MSN particles deposited in the tumor, an external low-power radiofrequency (RF) field triggered rapid drug release due to mechanical tumbling of the particle resulting in penetration of high amounts of drug across the blood-brain tumor interface and widespread drug delivery into the GBM. We loaded the nanoparticle with the drug 1400W, which is a potent inhibitor of the inducible nitric oxide synthase (iNOS). It has been shown that iNOS is preferentially expressed in BTICs and is required for their maintenance. Using the 1400W-loaded Fe@MSN and RF-triggered release, in vivo studies indicated that the treatment disrupted the BTIC population in hypoxic niches, suppressed tumor growth and significantly increased survival in BTIC-derived GBM xenografts.

P3637Relationship between serial measurements of NT-proBNP and cardiovascular events in patients with acute coronary syndrome

Background

Increased level of natriuretic peptides has been known as an important predictors of adverse cardiovascular (CV) outcomes in patients with acute coronary syndrome (ACS). We sought to evaluate clinical implication of N-terminal pro-brain natriuretic peptide (NT-proBNP) measured at initial and follow-up periods.

Methods

Serial NT-proBNP levels (on-admission and one-month post-PCI) were measured in ACS patients undergoing PCI (n=2,290). High NT-proBNP levels were determined according to the predefined age-specific criteria. Patients were stratified into 4 groups according to NT-proBNP levels (on-admission & one-month): (1) normal-normal group (n=1234, 53.9%); (2) high–normal group (n=257, 11.2%); (3) normal-high group (n=376, 16.4%); and (4) high-high group (n=423, 18.5%). Clinical events were defined as all-cause death and MACE (a composite of CV death, non-fatal MI, and ischemic stroke).

Results

With a median follow-up of 35.9 (IQR: 16.8, 54.5) months, all-cause death and MACE were occurred in 4.1% and 7.2%, respectively. NT-proBNP on-admission vs. at one-month did not differ significantly (median 391.6 [IQR: 143.9, 1402.3] vs. median 619.1 [IQR 240.1, 1616.1]; p=0.622), but the prevalence of high NT-proBNP was increased over time (25.3% to 34.9%; p<0.001). The rates of all-cause death and MACE significantly increased only in the high-high group compared with other groups (log-rank test, all p values <0.001, Figure). After adjustment, the high-high group remained significantly risky in terms with the occurrence of all-cause death (HR, 2.99; 95% CI, 1.65 to 5.41; p<0.001) and MACE (HR, 1.96; 95% CI, 1.28 to 3.01; p=0.002).

Figure 1

Conclusion

Serial measurements of NT-proBNP at on-admission and follow-up can help to stratify the risks of all-cause death and adverse CV events following PCI in ACS patients. About two-fifths of patients having high NT-proBNP level during hospitalization can be classified into the low-risk group for all-cause death and adverse CV events.

Acknowledgement/Funding

None