Nivolumab in sorafenib-naive and sorafenib-experienced patients with advanced hepatocellular carcinoma: 5-year follow-up from CheckMate 040

BACKGROUND

Patients with advanced hepatocellular carcinoma (aHCC) have a poor prognosis and high mortality. Nivolumab monotherapy demonstrated clinical benefit with an acceptable safety profile in patients with aHCC in the CheckMate 040 study. Five-year follow-up of the sorafenib-naive and sorafenib-experienced groups of CheckMate 040 is presented here.

PATIENTS AND METHODS

Patients received nivolumab monotherapy at dose levels of 0.1-10.0 mg/kg (dose-escalation phase) or 3 mg/kg (dose-expansion phase) every 2 weeks until disease progression or unacceptable toxicity. Primary endpoints were safety and tolerability (dose escalation), and objective response rate (ORR) by blinded independent central review (BICR) and by investigator as per RECIST version 1.1 (dose expansion).

RESULTS

Eighty sorafenib-naive and 154 sorafenib-experienced patients were treated. Minimum follow-up in both groups was 60 months. ORR as per BICR was 20% [95% confidence interval (CI) 12% to 30%] and 14% (95% CI 9% to 21%) in the sorafenib-naive and sorafenib-experienced groups, respectively. Responses occurred regardless of HCC etiology or baseline tumor cell programmed death-ligand 1 (PD-L1) expression levels. Median overall survival (OS) was 26.6 months (95% CI 16.6-30.6 months) and 15.1 months (95% CI 13.0-18.2 months) in sorafenib-naive and sorafenib-experienced patients, respectively. The 3-year OS rates were 28% in the sorafenib-naive and 20% in the sorafenib-experienced groups; 5-year OS rates were 14% and 12%, respectively. No new safety signals were identified; grade 3/4 treatment-related adverse events were observed in 33% and 21% of patients in the sorafenib-naive and sorafenib-experienced groups, respectively. Biomarker analyses showed that baseline PD-L1 expression ≥1% was associated with higher ORR and longer OS compared with PD-L1 <1%. In the sorafenib-naive group, patients with OS ≥3 years exhibited higher baseline CD8 T-cell density compared with those with OS <1 year.

CONCLUSION

With 5 years of follow-up, nivolumab monotherapy continued to provide durable clinical benefit with manageable safety in sorafenib-naive and sorafenib-experienced patients with aHCC.

miRNAs from Inflamed Gingiva Link Gene Signaling to Increased MET Expression

Several array-based microRNA (miRNA) expression studies independently showed increased expression of miRNAs hsa-miR-130a-3p, -142-3p, -144-3p, -144-5p, -223-3p, -17-5p, and -30e-5p in gingiva affected by periodontal inflammation. We aimed to determine direct target genes and signaling pathways regulated by these miRNAs to identify processes relevant to gingival inflammatory responses and tissue homeostasis. We transfected miRNA mimics (mirVana) for each of the 7 miRNAs separately into human primary gingival fibroblasts cultured from 3 different donors. Following RNA sequencing, differential gene expression and second-generation gene set enrichment analyses were performed. miRNA inhibition and upregulation was validated at the transcript and protein levels using quantitative reverse transcriptase polymerase chain reaction, Western blotting, and reporter gene assays. All 7 miRNAs significantly increased expression of the gene MET proto-oncogene, receptor tyrosine kinase (MET). Expression of known periodontitis risk genes CPEB1, ABCA1, and ATP6V1C1 was significantly repressed by hsa-miR-130a-3p, -144-3p, and -144-5p, respectively. The genes WASL, ENPP5, ARL6IP1, and IDH1 showed the most significant and strongest downregulation after hsa-miR-142-3p, -17-5p, -223-3p, and -30e-5p transfection, respectively. The most significantly regulated gene set of each miRNA related to cell cycle (hsa-miRNA-144-3p and -5p [Padj = 4 × 10-40 and Padj = 4 × 10-6], -miR-17-5p [Padj = 9.5 × 10-23], -miR-30e-5p [Padj = 8.2 × 10-18], -miR-130a-3p [Padj = 5 × 10-15]), integrin cell surface interaction (-miR-223-3p [Padj = 2.4 × 10-7]), and interferon signaling (-miR-142-3p [Padj = 5 × 10-11]). At the end of acute inflammation, gingival miRNAs bring together complex regulatory networks that lead to increased expression of the gene MET. This underscores the importance of mesenchymal cell migration and invasion during gingival tissue remodeling and proliferation in restoring periodontal tissue homeostasis after active inflammation. MET, a receptor of the mitogenic hepatocyte growth factor fibroblast secreted, is a core gene of this process.

Through-Space, Lone-Pair Promoted Aromatic Substitution: A Relay Mechanism Can Beat Out Direct Activation

We report a detailed experimental and theoretical analysis of through-space arene activation with halogens, tetrazoles and achiral esters and amides. Contrary to previously assumed direct activation through σ-complex stabilization, our results suggest that these reactions proceed by a relay mechanism wherein the lone pair-containing activators form exothermic π-complexes with electrophilic nitronium ion before transferring it to the probe ring through low barrier transition states. Noncovalent interactions (NCI) plots and Quantum Theory of Atoms in Molecules (QTAIM) analyses depict favorable interactions between the Lewis base (LB) and the nitronium ion in the precomplexes and the transition states, suggesting directing group participation throughout the mechanism. The regioselectivity of substitution also comports with a relay mechanism. In all, these data pave the way for an alternate platform of electrophilic aromatic substitution (EAS) reactions.

Transfer learning enables predictions in network biology

Mapping gene networks requires large amounts of transcriptomic data to learn the connections between genes, which impedes discoveries in settings with limited data, including rare diseases and diseases affecting clinically inaccessible tissues. Recently, transfer learning has revolutionized fields such as natural language understanding1,2 and computer vision3 by leveraging deep learning models pretrained on large-scale general datasets that can then be fine-tuned towards a vast array of downstream tasks with limited task-specific data. Here, we developed a context-aware, attention-based deep learning model, Geneformer, pretrained on a large-scale corpus of about 30 million single-cell transcriptomes to enable context-specific predictions in settings with limited data in network biology. During pretraining, Geneformer gained a fundamental understanding of network dynamics, encoding network hierarchy in the attention weights of the model in a completely self-supervised manner. Fine-tuning towards a diverse panel of downstream tasks relevant to chromatin and network dynamics using limited task-specific data demonstrated that Geneformer consistently boosted predictive accuracy. Applied to disease modelling with limited patient data, Geneformer identified candidate therapeutic targets for cardiomyopathy. Overall, Geneformer represents a pretrained deep learning model from which fine-tuning towards a broad range of downstream applications can be pursued to accelerate discovery of key network regulators and candidate therapeutic targets.

Burden of osteoarthritis in India and its states, 1990-2019: findings from the Global Burden of disease study 2019

OBJECTIVE

To describe the burden of osteoarthritis (OA) in India from 1990 to 2019.

DESIGN

Data from Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 were used. The burden of OA -knee OA, hip OA, hand OA, and other OA- was estimated for India and its states from 1990 to 2019 through a systematic analysis of prevalence, incidence, years lived with disability (YLD), and disability-adjusted life years (DALY) using methods reported in GBD 2019 study.

RESULT

Around 23.46 million individuals in India had OA in 1990; this increased to 62.35 million in 2019. The age-standardised prevalence of OA increased from 4,895 (95% uncertainty interval (UI):4,420-5,447) in 1990-5313 (95%UI:4,799-5,898) in 2019, per 100,000 persons. Similarly, DALYs due to OA increased from 0.79 million (95%UI:0.40-1.55) to 2.12 million (95%UI:1.07-4.23); while age-standardised DALYs increased from 164 (95%UI:83-325) to 180 (95%UI:91-361) per 100,000 persons from 1990 to 2019. OA was the 20^th most common cause of YLDs in India in 2019, accounting for 1.48% (95%UI:0.88-2.78) of all YLDs; increasing from 23rd most common cause in 1990 (1.25%(95%UI:0.74-2.34)). Knee OA was the most common form of OA, followed by hand OA. The prevalence, incidence, and DALYs for OA and knee OA were consistently higher in females than males.

CONCLUSION

The burden and impact of OA in India are substantial and is increasing. Adopting suitable control and preventive community measures to reduce modifiable risk factors (obesity, injuries, occupational stress) are needed to reduce the current and future burden of OA in India.

POS1425 THE BURDEN OF OSTEOARTHRITIS ACROSS THE STATES OF INDIA, 1990–2019: FINDINGS FROM THE GLOBAL BURDEN OF DISEASE STUDY 2019

Background

Few studies have reported the burden of osteoarthritis (OA) in different parts of India. However, no study has reported the detailed estimates of incidence, prevalence, and years lived with disability (YLDs) and its trends for OA (and its various sites) across the states of India over a long period of time.

Objectives

We aim to describe the state-wise prevalence, incidence, and YLDs for osteoarthritis (OA) in India from 1990 to 2019 according to age and sex.

Methods

Data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 were used. The burden of OA –including knee OA, hip OA, hand OA, and other OA– was estimated for India and its states from 1990 to 2019 through a systematic analysis of prevalence, incidence, and YLDs modelled data using the methods reported in the GBD 2019 Study. All estimates are presented as counts and age-standardised rates per 100,000 population, with uncertainty intervals (UIs).

Results

Around 23.46 million individuals in India had OA in 1990; this increased to 62.35 million in 2019. The age-standardised prevalence of OA increased from 4,895 (95% uncertainty interval (UI): 4,420–5,447) in 1990 to 5313 (95%UI: 4,799–5,898) in 2019, per 100,000. OA was the 20th most common cause of YLDs in India in 2019, accounting for 1·48% (95%UI: 0·88–2·78) of all YLDs; increasing from 23rd most common cause in 1990 (1·25% (95%UI: 0·74–2·34)). Knee OA was the most common form of OA, followed by hand OA. The prevalence, incidence, and YLDs for OA and knee OA were consistently higher in females than males. Uttar Pradesh (8.53 million (95%UI: 7.63–9.53), Maharashtra (6.37 million (95%UI: 5.75–7.06), and West Bengal (4.90 million (95%UI: 4.39–5.46) had the three highest levels of OA prevalence. Goa (5689 (95%UI: 5,125–6,282)), Rajasthan (5667 (95%UI: 5,097–6,305)), and Kerala (5658 (95%UI: 5,107–6,263)) had the highest age-standardised prevalence of OA in 2019, per 100,000 (Figure 1 A and B).

Conclusion

The burden and impact of OA in India are substantial and is increasing; however, it varied among states. Females were affected more commonly than males. Knee OA was the most prevalent site. With improvement in life expectancy and population ageing, greater increases are expected. Adopting suitable control and preventive community measures to reduce modifiable risk factors (such as obesity, injuries, occupational stress) are needed now to reduce the current and future burden of OA in India.

Disclosure of Interests

None declared

OP0035 WHAT EXPLAINS THE WORLDWIDE GRADIENT OF AGE AT ONSET OF RHEUMATOID ARTHRITIS ALONG LATITUDE? A MULTILEVEL ANALYSIS IN THE METEOR REGISTRY

Background

It has been suggested that rheumatoid arthritis (RA) starts at a younger age in cities with a lower latitude (closer to both sides of the equator). This consistent finding still remains to be explained. It has been hypothesized that latitude is a proxy for presence of genetic (eg. ACPA) and environmental risk factors (eg. smoking) for RA onset.

Objectives

To study how age at RA onset varies with latitude worldwide and to what extent patient and country level factors explain this variability.

Methods

RA patients from the worldwide METEOR registry were included. Age at diagnosis as a proxy for age at RA onset, measured at the patient level, was the main outcome. The explanatory variable was the absolute value of latitude, measured as the latitude of the hospital (hospital level). Patient factors considered potentially relevant were gender, RF and ACPA positivity, smoking status, symptom duration (months), year of first visit and BMI (all patient level). Country level factors were socioeconomic indicators (physician density, health expenditure, life expectancy, GDP per capita and gross enrolment in secondary school), derived from country statistics. We hypothesized that both patient and country level factors explain (ie. mediate) a relationship between latitude and age at diagnosis (Figure 1).

We applied Bayesian multilevel linear structural equations models, which not only quantify effects at multiple levels but also disentangle at which level the effects take place. For example, they can differentiate whether hospital or country latitude affects age at diagnosis.

We examined: 1. the total effect of latitude on age at diagnosis at hospital and country level (Main model); 2. the amount of the total effect that is mediated by patient factors at the patient and hospital level (Model A); and 3. the amount of the total effect that is mediated by country factors at the country level (Model B). In each model we disentangle the effect in different measurement levels. For example, a patient level variable can vary at the patient, hospital and country level.

Results

We included 39 782 patients nested in 94 hospitals nested in 17 countries. The mean age at diagnosis per country ranged from 39 to 55 years. The study spanned a range of latitude between 9.9 and 55.8 degrees (ie. from Nigeria to the United Kingdom). In the main model, we confirmed the association between latitude and age at diagnosis and found that it only occurred at the country level (not at the hospital level). Per degree increase in country latitude, the average age at diagnosis per country increased by 0.23 years (95% credibility interval 0.07; 0.40). At the hospital level however, this effect was negligible: β= 0.040 (-0.16; 0.31). Associations between latitude and several patient factors were found at the country level, but these patient factors only associated with age at diagnosis at the patient level, not at the country (or hospital) level (Model A). This means patient-factors did not explain the association between latitude and age at diagnosis at the country level (main effect changed from 0.23 before to 0.37 after inclusion of patient factors). In model B latitude associated with most country factors (except GDP per capita). Even though none of these variables separately were significantly associated with age at diagnosis, inclusion of the set of country level factors reduced the country level effect of latitude on age at diagnosis from 0.23 to almost zero: β=-0.033 (-0.51; 0.37). Sensitivity analyses with age at symptom onset as outcome provided similar results.

Conclusion

Patients living close at the equator indeed get RA far earlier than those living closer to the poles. We here suggest that, rather than due to variation in patients’ characteristics, this latitude gradient is a country level phenomenon explained by indicators of countries’ socioeconomic status, and not by patient specific genetic or environmental factors. This big data analysis in a worldwide prevalence cohort provides a direct link between countries’ levels of welfare and the onset of RA.

Disclosure of Interests

Sytske Anne Bergstra Grant/research support from: Pfizer, Alexandre Sepriano Speakers bureau: Novartis, Consultant of: UCB, Arvind Chopra: None declared, Lai-Ling Winchow: None declared, David Vega-Morales: None declared, Karen Solomon-Escoto: None declared, Xanthe Matthijssen: None declared, Robert B.M. Landewé Shareholder of: Director of Rheumatology Consultancy BV, Consultant of: Honoraria from AbbVie, AstraZeneca, BMS, Boehringer Ingelheim, Celgene, Galapagos, Gilead, Glaxo-Smith-Kline, Janssen, Eli-Lilly, Novartis, Pfizer, UCB Pharma.

BACH1 Binding Links the Genetic Risk for Severe Periodontitis with ST8SIA1

Genome-wide association studies identified various loci associated with periodontal diseases, but assigning causal alleles remains difficult. Likewise, the generation of biological meaning underlying a statistical association has been challenging. Here, we characterized the genetic association at the gene ST8SIA1 that increases the risk for severe periodontitis in smokers. We used CRISPR/dCas9 activation and RNA-sequencing to identify genetic interaction partners of ST8SIA1 and to determine its function in the cell. We used reporter gene assays to identify regulatory elements at the associated single-nucleotide polymorphisms (SNPs) and to determine effect directions and allele-specific changes of enhancer activity. Antibody electrophoretic mobility shift assays proved allele-specific transcription factor binding at the putative causal SNPs. We found the reported periodontitis risk gene ABCA1 as the top upregulated gene following ST8SIA1 activation. Gene set enrichment analysis showed highest effects on integrin cell surface interactions (area under the curve [AUC] = 0.85; q = 4.9 × 10-6) and cell cycle regulation (AUC = 0.89; q = 1.6 × 10-5). We identified 2 associated repressor elements in the introns of ST8SIA1 that bind the transcriptional repressor BACH1. The putative causative variant rs2012722 decreased BACH1 binding by 40%. We also pinpointed ST8SIA1 as the target gene of the association. ST8SIA1 inhibits cell adhesion with extracellular matrix proteins, integrins, and cell cycle, as well as enhances apoptosis. Likewise, tobacco smoke reportedly results in an inhibition of cell adhesion and a decrease in integrin-positive cells and cell growth. We conclude that impaired ST8SIA1 repression, independently caused by reduced BACH1 binding at the effect T allele, as well as by tobacco smoke, contributes to higher ST8SIA1 levels, and in smokers who carry the effect T allele, both factors would be additive with damaging effects on the gingival barrier integrity. The activity of ST8SIA1 is also linked with the periodontitis risk gene ABCA1.

Periodontitis Risk Variants at SIGLEC5 Impair ERG and MAFB Binding

Periodontitis is a common complex inflammatory disease of the oral cavity. It is characterized by inflammation of gingival tissues and alveolar bone loss. Recently, a genome-wide association study and 2 genome-wide association study meta-analyses found 2 associated regions (haplotype blocks) at the inhibitory immune receptor gene SIGLEC5 to increase the risk for periodontitis. The aims of the current study were the identification of the putative causal variants underlying these associations, characterization of their molecular biological effects, and validation of SIGLEC5 as the target gene. We mapped the associated single-nucleotide polymorphisms to DNA elements with predictive features of regulatory functions and screened the associated alleles for transcription factor (TF) binding sites. Antibody electrophoretic mobility shift assays (EMSAs) with allele-specific probes were used to identify TF binding and to quantify allele-specific effects on binding affinities. Luciferase reporter assays were used to quantify the effect directions and allele-specific strength of the associated regulatory elements. We used CRISPR-dCas9 gene activation to validate SIGLEC5 as a target of the association. EMSA in peripheral blood mononuclear cells showed that E-26 transformation-specific TF-related gene (ERG) binds at rs11084095, with almost complete loss of binding at the minor A-allele. Allele-specific reporter genes showed enhancer function of the DNA sequence at rs11084095, which was abrogated in the background of the A-allele. EMSA in B lymphocytes showed that TF MAF bZIP (MAFB) binds at the common G-allele of rs4284742, whereas the minor A-allele reduced TF binding by 69%, corresponding to 9-fold reduction of luciferase reporter gene activity by the A-allele. Using CRISPR-dCas9, we showed that the enhancer at rs4284742 strongly activated SIGLEC5 expression, validating this gene as the target gene of the association. We conclude that rs11084095 and rs4284742 are putatively causal for the genome-wide significant associations with periodontitis at SIGLEC5 that impair ERG and MAFB binding, respectively.

Filamin C Cardiomyopathy Variants Cause Protein and Lysosome Accumulation

[Figure: see text].

Probing the subcellular nanostructure of engineered human cardiomyocytes in 3D tissue

The structural and functional maturation of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) is essential for pharmaceutical testing, disease modeling, and ultimately therapeutic use. Multicellular 3D-tissue platforms have improved the functional maturation of hiPSC-CMs, but probing cardiac contractile properties in a 3D environment remains challenging, especially at depth and in live tissues. Using small-angle X-ray scattering (SAXS) imaging, we show that hiPSC-CMs matured and examined in a 3D environment exhibit a periodic spatial arrangement of the myofilament lattice, which has not been previously detected in hiPSC-CMs. The contractile force is found to correlate with both the scattering intensity (R ² = 0.44) and lattice spacing (R ² = 0.46). The scattering intensity also correlates with lattice spacing (R ² = 0.81), suggestive of lower noise in our structural measurement than in the functional measurement. Notably, we observed decreased myofilament ordering in tissues with a myofilament mutation known to lead to hypertrophic cardiomyopathy (HCM). Our results highlight the progress of human cardiac tissue engineering and enable unprecedented study of structural maturation in hiPSC-CMs.

Switching a HO···π Interaction to a Nonconventional OH···π Hydrogen Bond: A Completed Crystallographic Puzzle

In this article, we present crystallographic and spectroscopic evidence of a tunable system wherein a HO···π interaction switches incrementally to a nonconventional OH···π hydrogen bonding (HB) interaction. More specifically, we report the synthesis of substituted forms of model system 1 to study the effects of aryl ring electronic density on the qualitative characteristics of OH···π hydrogen bonds therein. The OH stretch in experimental infrared data, in agreement with density-functional theory (DFT) calculations, shows continuous red-shifts as the adjacent ring becomes more electron rich. For example, the OH stretch of an amino-substituted analogue is red-shifted by roughly 50 cm^-1 compared to the same stretch in the CF₃ analogue, indicating a significantly stronger HB interaction in the former. Moreover, DFT calculations (ωB97XD/6-311+G**) predict that increasing electronic density on the adjacent top ring reduces the aryl π-OH σ* energy gap with a concomitant enhancement of the OH n-π* energy gap. Consequently, a dominant π-σ* interaction in the amino substituted analogue locks the system in the in-form while a favorable n-π* interaction reverses the orientation of the oxygen-bound hydrogen in its protonated form. Additionally, the ¹H NMR data of various analogues reveal that stronger OH···π interactions in systems with electron-rich aromatic rings slow exchange of the alcoholic proton, thereby revealing coupling with the geminal proton. Finally, X-ray crystallographic analyses of a spectrum of analogues clearly visualize the three distinct stages of "switch"-starting with exclusive HO···π, to partitioned HO···π/OH···π, and finally to achieving exclusive OH···π forms. Furthermore, the crystal structure of the amino analogue reveals an interesting feature in which an extended HB network, involving two conventional (NH···O) and two nonconventional (OH···π) HBs, dimerizes and anchors the molecule in the unit cell.

THYROIDITIS DEVELOPING POST INITIATION OF OCTREOTIDE IN A CASE OF TSH SECRETING TUMOR

Thyroiditis developing post pituitary surgery in a case of TSH secreting tumor has been reported, albeit rarely. A 46 year old female was treated as a case of hypothyroidism for almost five years, however, TSH levels remained unsuppressed in spite of increasing thyroxine doses. A cyclic pattern of TSH with T3 secretion was observed after stopping thyroxine, though T4 levels were normal. T3 suppression test revealed a non suppressed TSH and MRI sella revealed a pituitary mass with Grade 1 cavernous sinus invasion. With a diagnosis of TSH secreting tumor, the patient was initiated on octreotide therapy. TFT normalized within 4 days of initiation of octreotide, tumor size reduced by about 30% within 2 months of therapy and goiter size reduced to almost half with octreotide therapy. Anti TPO levels which were initially negative became positive within a month of octreotide therapy and FNAC thyroid revealed thyroiditis. To the best of our knowledge, this is the second case report of development of thyroiditis after octreotide therapy. The immunomodulatory role of TSH and somatostatin may have a role in the development of thyroiditis in this case.

AB0641 MANAGING ANKYLOSING SPONDYLITIS (AS) WITH SHORT TERM BIOSIMILAR ADALIMUMAB REGIMEN IN A RESOURCE STRAPPED SETTING: A PROTOCOL DRIVEN COMMUNITY CLINIC ORIENTED STUDY

Background:

We were handicapped by the exorbitant cost of innovator anti-Tumour Necrosis Factor (TNF) drugs. Despite limited use, we sometimes observed long-term benefits following short term induction like use. Emboldened by advent of biosimilars, we carried out an investigational study.

Objectives:

To evaluate the effectiveness of a short regimen of biosimilar (Bs) Adalimumab in AS

Methods:

50 consenting patients (86% B27+) naïve for biologics and negative for latent TB screen were enrolled into an observational design study of one year; Baseline mean values for age, duration, ASDAS and CRP was 31 years, 98.8 months, 4.6 and 64 mg per dl respectively. During the first year, patients were begun with 40 mg Bs Adalimumab (Bs-ADL) (Exemptia™), injected fortnight, for 12-16 weeks. No patient received DMARD or steroid in the first year of study. Patients continued standard of care follow up program in the clinic. The ASAS (Assessment Spondyloarthritis International Society) improvement indices were used. Standard intention-to-treat analysis was performed; significant p <0.05.

Results:

Optimum ASAS 40 improvement was observed at week 12 (68%); substantial improvement lasted till week 36. At one year, the ASAS 40 was 38%; ASAS partial remission 22% patients. Pro-inflammatory cytokines (IL-6, TNF α and IL-17) showed conspicuous reduction; maximum drop in IL-6 at week 24 (See Figure). 11 patients withdrew in the first year. 30 patients completed two years and 22 patients completed 3 year follow up. Over time, there was substantial loss in the ASAS 20 and 40 responses but patients seemed satisfied with the on-going symptomatic relief and improved function. Admittedly, patients showed more adherences to advice on physical exercise and stress reduction. Flares were more frequent after 1 year requiring short term round the clock NSAID; only 5 patients could afford to repeat a short term Bs-ADL regimen and one patient underwent hip arthroplasty. None received steroids and 5 patients were begun on Sulfasalazine in the second year and monitored. We could not evaluate structural modification (AS). Selected outcomes over 2 and 3 years from the current study will be compared to matched control (derived from the clinic database). None developed TB or any serious drug related toxicity. 2 patients developed recurrent uveitis.

Conclusion:

This real life documented experience unravelled impressive long term benefits following a kick start short term induction regimen of Biosimilar Adalimumab in AS. Though contrary to standard practice, this seemed a practical solution in our setting. We speculate a psychological and motivational boost rather than a prolonged real time biological effect (Bs-ADL) for this phenomenon. Our study has important socioeconomic bearing and merits validation.

Acknowledgement:

This was essentially a non-commercial investigator-initiated study. Zydus Cedilla India provided a generous research grant with free of cost Bs_ADL to several patients and a large concession in the cost to the rest.

Disclosure of Interests:

Arvind Chopra Grant/research support from: Zydus Pharamceutical Ltd India, Nagnath Khadke: None declared, Manjit Saluja: None declared, Toktam Kianifard: None declared, Anuradha Venugopalan: None declared

AB0585 SINGLE CENTER EXPERIENCE OF CLINICAL PROFILE OF INFLAMMATORY MYOSITIS FROM INDIA

Background:

Clinical profile of myositis differs in respect of the setting. We present a single center experience from a community based referral center

Objectives:

STUDY CLINICAL PROFILE OF INFLAMMATORY MYOSITIS (IM)

Methods:

We present data from 114 patients of connective tissue disorders (CTD) with dominant Inflammatory Myopathy(IM) evaluated in CRD where we have patient database since 1996. Standard investigations & ELISA, immunoblot and nephlometry to assay autoantibodies (AAb) were done. Data extraction done from 2005-2017

Results:

36 and 28 patients respectively diagnosed as dominant idiopathic dematomyositis (DM) and polymyositis (PM); remaining 41 patients showed overlap (OCTD). Mean onset age range 33-40 years in each subset with women dominance. Exclusive proximal muscle involvement seen 64% DM, 67% PM and 43% OCTD. 12 of OCTD showed classical DM rash. Raynauds’s phenomenon was seen in 38% (25% DM, 10% PM, 65% OCTD). 83% OCTD showed inflammatory polyarthritis; DM 29% and PM 42%. Two patients DM also diagnosed malignancy (ovarian CA). 25% DM, nil PM and 31.7% OCTD showed CT based lung findings. Mean creatinine phosphokinase at diagnosis were DM 1580, PM 2239 & OCTD 830. EMG required in 48 patients confirmed diagnosis (DM 17, PM 16 and OCTD 15). Seven patients with diagnostic dilemma/ poor therapy response required muscle histopathology confirmation. 59% DM,69% PM and 84% OCTD were seropositive ANA positive in 71%(ENA profile available for most). All Patients received steroids. Methotrexate prescribed in (92%), Azthioprine in (28%), hydroxychloroquine in (88%) with majority showing good response. Mycophenolate prescribed in (6%) for aggressive disease, IVIG in 2 patients for acute IIM with interstitial pneumonitis. Rituximab was prescribed in 4 resistant cases; all responding favourably. Mortality data of 4 patients(severe myositis(1), interstitial pneumonitis(1), ovarian cancer(1), septic shock(1)) was available. Antesynthatase syndrome noted in 9 patients.

Conclusion:

Overlap CTD with myositis seems more common profile than DM or PM. Response to therapy was satisfactory with steroids and methotrexate being the mainstay. Rituximab is a promising biological agent in chronic resistant cases.

References:

[1]A Kumar. Idiopathic Inflammatory Myopathies. Suppliment to JAPI, JUNE 2006, VOL. 54; Pg 62-66

[2]R Porkodi et al Clinical Spectrum of Inflammatory Myositis in South India - A Ten Year Study. J Assoc Physicians India 2002;50:1255-1258

[3]Chowdhary V, Aggarwal A, Misra R. Prevalence and clinical association of myositis-specific autoantibodies in North Indian patients with idiopathic inflammatory myopathy. APLAR J Rheumatol 2 001.

Acknowledgments :

STAFF AND PATIENTS OF CENTER FOR RHEUMATIC DISEASES, PUNE

Disclosure of Interests: :

NACHIKET KULKARNI Speakers bureau: PFIZER, NOVARTIS, YANSEN, Anuradha Venugopalan: None declared, MANJIT SALUJA: None declared, Arvind Chopra Grant/research support from: Zydus Pharamceutical Ltd India

SAT0158 EFFICACY AND SAFETY OF FILGOTINIB IN METHOTREXATE-NAÏVE PATIENTS WITH RHEUMATOID ARTHRITIS: FINCH 3 52-WEEK RESULTS

Background:

Filgotinib (FIL) is a potent, selective JAK 1 inhibitor. FINCH 3 assessed FIL efficacy and safety in methotrexate (MTX)-naïve patients (pts) with rheumatoid arthritis (RA); week (W)24 primary outcome results were previously presented.1

Objectives:

To report FINCH 3 (NCT02886728) results through W52.

Methods:

This global, phase 3, double-blind, active-controlled study randomised MTX-naïve pts with moderately to severely active RA 2:1:1:2 to oral FIL 200 mg once daily + MTX ≤20 mg weekly, FIL 100 mg + MTX, FIL 200 mg monotherapy (mono) + placebo (PBO), or PBO + MTX up to W52. Comparisons at W52 were not adjusted for multiplicity. Safety was assessed from adverse events and laboratory abnormalities.

Results:

Of 1249 treated pts, 975 received study drug through W52. FIL efficacy was sustained up to W52. Treatment with FIL + MTX or FIL mono increased proportions of pts achieving ACR20/50/70 and clinical disease remission by DAS28(CRP) <2.6 (FIL 200 mg + MTX, 53%; FIL mono, 46%), CDAI, SDAI, and Boolean criteria; improved HAQ-DI; and halted radiographic progression vs MTX alone (Table 1 andFigure). Safety was consistent with W24 data (Table 2).

Table 1.

Efficacy outcomes at week 52

FIL 200 mg + MTX (n = 416)FIL 100 mg + MTX (n = 207)FIL 200 mg(n = 210)MTX(n = 416)ACR20, %75.0***73.4**74.8***61.8ACR50, %62.3***59.4**61.4**48.3ACR70, %47.8***40.1*45.2***29.8mTSSa0.21***0.27*0.23**0.74HAQ-DIb−1.00***−0.97−0.95*−0.88

aLeast-squares mean change from baseline.

bMean change from baseline.

*, p <0.05;**, p <0.01;***, p <0.001 vs MTX alone; not adjusted for multiplicity.

FIL, filgotinib; mTSS, van der Heijde modified total Sharp score; MTX, methotrexate.

Table 2.

Safety outcomes through week 52

Event, n (%)FIL 200 mg + MTX(n = 416)FIL 100 mg + MTX(n = 207)FIL 200 mg(n = 210)MTX(n = 416)All AEs318 (76.4)164 (79.2)143 (68.1)305 (73.3)Serious AEs26 (6.3)13 (6.3)17 (8.1)28 (6.7)Infection148 (35.6)76 (36.7)75 (35.7)157 (37.7)Serious infection5 (1.2)3 (1.4)5 (2.4)8 (1.9)Herpes zoster6 (1.4)3 (1.4)4 (1.9)4 (1.0)VTE0004 (1.0)MACE (adjudicated)4 (1.0)1 (0.5)2 (1.0)2 (0.5)Malignancya1 (0.2)004 (1.0)NMSC2 (0.5)001 (0.2)Death3 (0.7)b1 (0.5)c00

aExcluding NMSC.

b1 lupus cardiomyopathy, 1 atypical interstitial pneumonia, 1 non–treatment-emergent cardiovascular death.

cDissecting cerebral and vertebral aneurysm.

AE, adverse event; FIL, filgotinib; MACE, major adverse cardiovascular event; MTX, methotrexate; NMSC, nonmelanoma skin cancer; VTE, venous thromboembolism.

Conclusion:

Efficacy of FIL 200 mg + MTX, FIL 100 mg + MTX, and FIL 200 mg mono was sustained through W52, with faster onset1and consistently numerically greater efficacy for FIL 200 vs 100 mg. No new safety signals were observed.

References:

[1]Westhovens, et al.Ann Rheum Dis.2019;78(Suppl2):259–60.

Disclosure of Interests:

Rene Westhovens Grant/research support from: Celltrion Inc, Galapagos, Gilead, Consultant of: Celltrion Inc, Galapagos, Gilead, Speakers bureau: Celltrion Inc, Galapagos, Gilead, William Rigby Consultant of: Gilead Sciences, Inc., Désirée van der Heijde Consultant of: AbbVie, Amgen, Astellas, AstraZeneca, BMS, Boehringer Ingelheim, Celgene, Cyxone, Daiichi, Eisai, Eli-Lilly, Galapagos, Gilead Sciences, Inc., Glaxo-Smith-Kline, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sanofi, Takeda, UCB Pharma; Director of Imaging Rheumatology BV, Daniel Ching Grant/research support from: AbbVie, Gilead Sciences, Inc., Pfizer, Sanofi, Consultant of: AbbVie, Pfizer, Speakers bureau: AbbVie, William Stohl Grant/research support from: GlaxoSmithKline, Consultant of: Janssen Research & Development, Jonathan Kay Grant/research support from: Gilead Sciences, Inc., Pfizer, Novartis Pharmaceuticals Corporation, Consultant of: Alvotech Suisse AG; Arena Pharmaceuticals, Inc.; Boehringer Ingelheim GmbH; Celltrion Healthcare Co. Ltd.; Merck Sharp & Dohme Corp.; Mylan Inc.; Novartis AG; Samsung Bioepis; Sandoz, Inc; UCB, Inc., Arvind Chopra Grant/research support from: Zydus Pharamceutical Ltd India, Beatrix Bartok Shareholder of: Gilead Sciences Inc., Employee of: Gilead Sciences Inc., Franziska Matzkies Shareholder of: Gilead Sciences, Inc., Employee of: Gilead Sciences, Inc., Zhaoyu Yin Shareholder of: Gilead Sciences, Inc., Employee of: Gilead Sciences, Inc., Ying Guo Shareholder of: Gilead Sciences, Inc., Employee of: Gilead Sciences, Inc., Chantal Tasset Shareholder of: Galapagos (share/warrant holder), Employee of: Galapagos, John Sundy Shareholder of: Gilead Sciences, Inc., Employee of: Gilead Sciences, Inc., Angelika Jahreis Shareholder of: Gilead Sciences, Inc., Employee of: Gilead Sciences, Inc., Neelufar Mozaffarian Shareholder of: Gilead, Employee of: Gilead, Osvaldo Messina Speakers bureau: Amgen; Americas Health Foundation; Pfizer, Robert B.M. Landewé Consultant of: AbbVie; AstraZeneca; Bristol-Myers Squibb; Eli Lilly & Co.; Galapagos NV; Novartis; Pfizer; UCB Pharma, Tatsuya Atsumi Grant/research support from: Eli Lily Japan K.K., Alexion Pharmaceuticals, Inc., Bristol-Myers Squibb Co., AbbVie Inc., Daiichi Sankyo Co., Ltd., Pfizer Inc., Chugai Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Co., Astellas Pharma Inc., Consultant of: Gilead Sciences, Inc., Eli Lilly Japan K.K., UCB Japan Co. Ltd., AbbVie Inc., Daiichi Sankyo Co., Ltd., Pfizer Inc., Chugai Pharmaceutical Co., Ltd., Speakers bureau: Eli Lilly Japan K.K., UCB Japan Co. Ltd., Bristol-Myers Squibb Co., AbbVie Inc., Eisai Co. Ltd., Otsuka Pharmaceutical Co., Ltd., Daiichi Sankyo Co., Ltd., Pfizer Inc., Chugai Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Co., Takeda Pharmaceutical Co., Ltd., Astellas Pharma Inc., Gerd Rüdiger Burmester Consultant of: AbbVie Inc, Eli Lilly, Gilead, Janssen, Merck, Roche, Pfizer, and UCB Pharma, Speakers bureau: AbbVie Inc, Eli Lilly, Gilead, Janssen, Merck, Roche, Pfizer, and UCB Pharma

Myosin Sequestration Regulates Sarcomere Function, Cardiomyocyte Energetics, and Metabolism, Informing the Pathogenesis of Hypertrophic Cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is caused by pathogenic variants in sarcomere protein genes that evoke hypercontractility, poor relaxation, and increased energy consumption by the heart and increased patient risks for arrhythmias and heart failure. Recent studies show that pathogenic missense variants in myosin, the molecular motor of the sarcomere, are clustered in residues that participate in dynamic conformational states of sarcomere proteins. We hypothesized that these conformations are essential to adapt contractile output for energy conservation and that pathophysiology of HCM results from destabilization of these conformations.

METHODS

We assayed myosin ATP binding to define the proportion of myosins in the super relaxed state (SRX) conformation or the disordered relaxed state (DRX) conformation in healthy rodent and human hearts, at baseline and in response to reduced hemodynamic demands of hibernation or pathogenic HCM variants. To determine the relationships between myosin conformations, sarcomere function, and cell biology, we assessed contractility, relaxation, and cardiomyocyte morphology and metabolism, with and without an allosteric modulator of myosin ATPase activity. We then tested whether the positions of myosin variants of unknown clinical significance that were identified in patients with HCM, predicted functional consequences and associations with heart failure and arrhythmias.

RESULTS

Myosins undergo physiological shifts between the SRX conformation that maximizes energy conservation and the DRX conformation that enables cross-bridge formation with greater ATP consumption. Systemic hemodynamic requirements, pharmacological modulators of myosin, and pathogenic myosin missense mutations influenced the proportions of these conformations. Hibernation increased the proportion of myosins in the SRX conformation, whereas pathogenic variants destabilized these and increased the proportion of myosins in the DRX conformation, which enhanced cardiomyocyte contractility, but impaired relaxation and evoked hypertrophic remodeling with increased energetic stress. Using structural locations to stratify variants of unknown clinical significance, we showed that the variants that destabilized myosin conformations were associated with higher rates of heart failure and arrhythmias in patients with HCM.

CONCLUSIONS

Myosin conformations establish work-energy equipoise that is essential for life-long cellular homeostasis and heart function. Destabilization of myosin energy-conserving states promotes contractile abnormalities, morphological and metabolic remodeling, and adverse clinical outcomes in patients with HCM. Therapeutic restabilization corrects cellular contractile and metabolic phenotypes and may limit these adverse clinical outcomes in patients with HCM.

Sarco/endoplasmic reticulum Ca2+-ATPase is a more effective calcium remover than sodium-calcium exchanger in human embryonic stem cell-derived cardiomyocytes

Human pluripotent stem cell (hPSCs)-derived ventricular (V) cardiomyocytes (CMs) display immature Ca2+–handing properties with smaller transient amplitudes and slower kinetics due to such differences in crucial Ca2+-handling proteins as the poor sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) pump but robust Na+-Ca2+ exchanger (NCX) activities in human embryonic stem cell (ESC)-derived VCMs compared with adult. Despite their fundamental importance in excitation-contraction coupling, the relative contribution of SERCA and NCX to Ca2+-handling of hPSC-VCMs remains unexplored. We systematically altered the activities of SERCA and NCX in human embryonic stem cell-derived ventricular cardiomyocytes (hESC-VCMs) and their engineered microtissues, followed by examining the resultant phenotypic consequences. SERCA overexpression in hESC-VCMs shortened the decay of Ca2+ transient at low frequencies (0.5 Hz) without affecting the amplitude, SR Ca2+ content and Ca2+ baseline. Interestingly, short hairpin RNA-based NCX suppression did not prolong the transient decay, indicating a compensatory response for Ca2+ removal. Although hESC-VCMs and their derived microtissues exhibited negative frequency-transient/force responses, SERCA overexpression rendered them less negative at high frequencies (>2 Hz) by accelerating Ca2+ sequestration. We conclude that for hESC-VCMs and their microtissues, SERCA, rather than NCX, is the main Ca2+ remover during diastole; poor SERCA expression is the leading cause for immature negative-frequency/force responses, which can be partially reverted by forced expression. Combinatorial approach to mature calcium handling in hESC-VCMs may help shed further mechanistic insights.

NEW & NOTEWORTHY In this study of human pluripotent stem cell-derived cardiomyocytes, we studied the role of sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) and Na+-Ca2+ exchanger (NCX) in Ca2+ handling. Our data support the notion that SERCA is more effective in cytosolic calcium removal than the NCX.

Abstract 462: High Speed Imaging of Single Cardiomyocyte Action Potentials Using a Far-red Genetically Encoded Voltage Sensor

The ability to image cardiac membrane potentials allows for the observation of cellular communication and electrical activity, both of which are important to maintain cardiac syncytium; these can be altered in diseases (e.g. Long QT Syndrome). Traditionally voltage dyes such as Di-8-ANEPPS have been used to optically measure action potentials (APs). However, these dyes express transiently, have poor signal to noise ratios, and are toxic. More recently, genetically encoded voltage indicators (GEVIs) have been developed to replace state-of-the-art voltage dyes, but sensors currently used within the cardiac field exhibit poor kinetics and/or low signal to noise ratios (SNR). Recently, Archon1, a new genetically encoded voltage sensor, was developed in the neuroscience field; this sensor exhibits excellent membrane localization, temporal sensitivity, and SNR, enabling the optical detection of individual spikes in neurons. Here we use Archon1 for the first time in cardiac cells, to monitor single cell cardiac APs in 2D and 3D in vitro systems in response to different environmental stimuli. Human induced pluripotent stem cell-derived cardiomyocytes were infected with Archon1 and imaged using a one-photon fluorescence microscope equipped with a high speed sCMOS camera to demonstrate cardiac AP tracings. The kinetics and SNR of Archon1 are compared to traditional electrophysiology and Di-8-ANEPPS measurements. Additionally, E-4031 (K+ Channel Blocker) and Nifedipine (Ca2+ Channel Blocker) were used to demonstrate the sensitivity of this sensor in a drug dosage study. To study the APs of single cells within a 3D engineered microtissue, cardiomyocytes expressing Archon1 were seeded into a force transducing micro-pillar device and the APs for optically isolated cells were recorded. Demonstration of this new genetically encoded voltage sensor in cardiac cells enables the monitoring of single and multi-cell APs in 2D and 3D applications and can be extended to in vivo. This tool, newly applied to cardiac biology and tissue engineering will allow for better and more accurate observation of cardiac electrical activity to probe human cardiovascular disease.

Abstract 482: Modeling PKP2 Mutation Associated Arrhythmogenic Cardiomyopathy With CRISPR-edited iPSC-derived Cardiomyocytes in Engineered Cardiac Tissues

Arrhythmogenic cardiomyopathy (ACM), also known as arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C), is a leading cause of sudden death among young adults. Over half of ACM cases are associated with inherited desmosome gene mutations, most commonly in the gene PKP2 which encodes plakophilin-2. One of the obstacles to better understanding ACM pathogenesis is the lack of appropriate models which encompass the early stages of disease development; this imposes significant constraints on the advancement of clinical therapies. The recent advent of human induced pluripotent stem cells derived cardiomyocytes (hiPSC-CMs) has enabled the development of models for studying human cardiac cell biology and pathology. In this work, we combine hiPSC-CMs, CRISPR/Cas9 genome editing, and engineered cardiac tissue platforms to develop human in vitro systems for investigating the molecular mechanisms of ACM pathogenesis.

Isogenic control and mutant cell lines of hiPSC-CMs harboring ACM-associated PKP2 mutations were generated using CRISPR/Cas9 technology. Specifically, the PKP2tv cell line has an early truncation in plakophilin-2 that mimics PKP2 c.235C>T found in multiple family lineages. The effects of the PKP2tv mutation on cardiac tissue contractility were characterized using a 3D cardiac micro-tissue (CMT) platform. CMTs composed of PKP2tv cardiomyocytes were shown to have significantly decreased contractile forces compared to the control, which recapitulates the reduced ventricular systolic function seen in ACM patients. This result demonstrated the feasibility of using the hiPSC-derived tissue-engineering model to recapitulate ACM disease phenotype and allow for future investigation into the disease mechanisms.

Abstract 341: Efficient Large-scale Sarcomere Tracking (sarctrack) to Assess HCM Variants in iPSC-CMs

Variants that drive HCM and associated adverse patient outcomes are found in the cardiac sarcomere. These variants range from those that are known to be pathogenic to those that are likely pathogenic or even variants of unknown significance (VUS). CRISPR/Cas-9 engineering has accelerated our ability to generate variants in iPSC to probe changes in cellular function and assess cellular pathogenicity in VUSs. However, iPSC-CMs are not as functionally mature as adult cardiomyocytes. For this reason we have developed a platform to assess contractile function directly at the level of the sarcomere. We use a custom built MatLab algorithm to assess sarcomere length, contraction time, relaxation time, and beat rate of individual sarcomeres within iPSC-CMs. Sarcomeres are visualised using reporter lines that have been engineered with an N-terminal TTN-GFP. We assess the contractile function of thick filament variants in MYH7 and MYBPC3. We show the ability to detect changes in key contractile parameters. This platform allows the screening of pharmacological compounds against these reporter lines with engineered variants.

Development of methods for the preparation of radiopure 82Se sources for the SuperNEMO neutrinoless double-beta decay experiment

A radiochemical method for producing 82Se sources with an ultra-low level of contamination of natural radionuclides (40K, decay products of 232Th and 238U) has been developed based on cation-exchange chromatographic purification with reverse removal of impurities. It includes chromatographic separation (purification), reduction, conditioning (which includes decantation, centrifugation, washing, grinding, and drying), and 82Se foil production. The conditioning stage, during which highly dispersed elemental selenium is obtained by the reduction of purified selenious acid (H2SeO3) with sulfur dioxide (SO2) represents the crucial step in the preparation of radiopure 82Se samples. The natural selenium (600 g) was first produced in this procedure in order to refine the method. The technique developed was then used to produce 2.5 kg of radiopure enriched selenium (82Se). The produced 82Se samples were wrapped in polyethylene (12 μm thick) and radionuclides present in the sample were analyzed with the BiPo-3 detector. The radiopurity of the plastic materials (chromatographic column material and polypropylene chemical vessels), which were used at all stages, was determined by instrumental neutron activation analysis. The radiopurity of the 82Se foils was checked by measurements with the BiPo-3 spectrometer, which confirmed the high purity of the final product. The measured contamination level for 208Tl was 8–54 μBq/kg, and for 214Bi the detection limit of 600 μBq/kg has been reached.

SarcTrack

RATIONALE

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in combination with CRISPR/Cas9 genome editing provide unparalleled opportunities to study cardiac biology and disease. However, sarcomeres, the fundamental units of myocyte contraction, are immature and nonlinear in hiPSC-CMs, which technically challenge accurate functional interrogation of contractile parameters in beating cells. Furthermore, existing analysis methods are relatively low-throughput, indirectly assess contractility, or only assess well-aligned sarcomeres found in mature cardiac tissues.

OBJECTIVE

We aimed to develop an analysis platform that directly, rapidly, and automatically tracks sarcomeres in beating cardiomyocytes. The platform should assess sarcomere content, contraction and relaxation parameters, and beat rate.

METHODS AND RESULTS

We developed SarcTrack, a MatLab software that monitors fluorescently tagged sarcomeres in hiPSC-CMs. The algorithm determines sarcomere content, sarcomere length, and returns rates of sarcomere contraction and relaxation. By rapid measurement of hundreds of sarcomeres in each hiPSC-CM, SarcTrack provides large data sets for robust statistical analyses of multiple contractile parameters. We validated SarcTrack by analyzing drug-treated hiPSC-CMs, confirming the contractility effects of compounds that directly activate (CK-1827452) or inhibit (MYK-461) myosin molecules or indirectly alter contractility (verapamil and propranolol). SarcTrack analysis of hiPSC-CMs carrying a heterozygous truncation variant in the myosin-binding protein C ( MYBPC3) gene, which causes hypertrophic cardiomyopathy, recapitulated seminal disease phenotypes including cardiac hypercontractility and diminished relaxation, abnormalities that normalized with MYK-461 treatment.

CONCLUSIONS

SarcTrack provides a direct and efficient method to quantitatively assess sarcomere function. By improving existing contractility analysis methods and overcoming technical challenges associated with functional evaluation of hiPSC-CMs, SarcTrack enhances translational prospects for sarcomere-regulating therapeutics and accelerates interrogation of human cardiac genetic variants.

Force Generation via β-Cardiac Myosin, Titin, and α-Actinin Drives Cardiac Sarcomere Assembly from Cell-Matrix Adhesions

Truncating mutations in the sarcomere protein titin cause dilated cardiomyopathy due to sarcomere insufficiency. However, it remains mechanistically unclear how these mutations decrease sarcomere content in cardiomyocytes. Utilizing human induced pluripotent stem cell-derived cardiomyocytes, CRISPR/Cas9, and live microscopy, we characterize the fundamental mechanisms of human cardiac sarcomere formation. We observe that sarcomerogenesis initiates at protocostameres, sites of cell-extracellular matrix adhesion, where nucleation and centripetal assembly of α-actinin-2-containing fibers provide a template for the fusion of Z-disk precursors, Z bodies, and subsequent striation. We identify that β-cardiac myosin-titin-protocostamere form an essential mechanical connection that transmits forces required to direct α-actinin-2 centripetal fiber assembly and sarcomere formation. Titin propagates diastolic traction stresses from β-cardiac myosin, but not α-cardiac myosin or non-muscle myosin II, to protocostameres during sarcomerogenesis. Ablating protocostameres or decoupling titin from protocostameres abolishes sarcomere assembly. Together these results identify the mechanical and molecular components critical for human cardiac sarcomerogenesis.

Comparative reliability and diagnostic performance of conventional 3T magnetic resonance imaging and 1.5T magnetic resonance arthrography for the evaluation of internal derangement of the hip

Objective

To compare the diagnostic accuracy of conventional 3T MRI against 1.5T MR arthrography (MRA) in patients with clinical femoroacetabular impingement (FAI).

Methods

Sixty-eight consecutive patients with clinical FAI underwent both 1.5T MRA and 3T MRI. Imaging was prospectively analysed by two musculoskeletal radiologists, blinded to patient outcomes and scored for internal derangement including labral and cartilage abnormality. Interobserver variation was assessed by kappa analysis. Thirty-nine patients subsequently underwent hip arthroscopy and surgical results and radiology findings were analysed.

Results

Both readers had higher sensitivities for detecting labral tears with 3T MRI compared to 1.5T MRA (not statistically significant p=0.07). For acetabular cartilage defect both readers had higher statistically significant sensitivities using 3T MRI compared to 1.5T MRA (p=0.02). Both readers had a slightly higher sensitivity for detecting delamination with 1.5T MRA compared to 3T MRI, but these differences were not statistically significant (p=0.66). Interobserver agreement was substantial to perfect agreement for all parameters except the identification of delamination (3T MRI showed moderate agreement and 1.5T MRA substantial agreement).

Conclusion

Conventional 3T MRI may be at least equivalent to 1.5T MRA in detecting acetabular labrum and possibly superior to 1.5T MRA in detecting cartilage defects in patients with suspected FAI.

Key Points

• Conventional 3T MRI is equivalent to 1.5T MRA for diagnosing labral tears.

• Conventional 3T MRI is superior to 1.5T MRA for diagnosing acetabular cartilage defect.

• Conventional 3T MRI is equivalent to 1.5T MRA for diagnosing cartilage delamination.

• Symptom severity score was significantly higher (p<0.05) in group proceeding to surgery.

Association of heat stress protein 90 and 70 gene polymorphism with adaptability traits in Indian sheep (Ovis aries)

Heat stress proteins assist cellular proteins in the acquisition of native structure. The present research was conducted to study how thermo-tolerance is modulated by HSP90 and HSP70 gene polymorphism and its association with hemato-physio-biochemical parameters, supported by their expression profiles in Chokla, Magra, Marwari, and Madras Red sheep breeds. Least square analysis revealed significant effect (P < 0.05) of season and breed on all the physiological parameters, i.e., temperature, respiratory rate, and pulse rate (a.m. and p.m.), as well as hematological parameters like Hb, packed cell volume, total erythrocyte count (TEC), neutrophil/lymphocyte (N/L) ratio, and total leukocyte count (TLC). There was a significant influence (P < 0.05) of breed on biochemical parameters such as glucose, SGOT, phosphorous, triglyceride, and cholesterol. Eight fragments were amplified and sequenced in HSP90, and 70 genes and 13 single-nucleotide polymorphisms (SNPs) were identified. Tetra-primer amplification refractory mutation system PCR, PCR-RFLP, and allele-specific PCR genotyping protocols were developed for large-scale genotyping of five SNPs. A significant difference (P < 0.05) of rectal temperature (a.m.), respiratory rate (p.m.), triglyceride, and total protein was observed at SNP01; albumin at SNP2; pulse rate (p.m.) at SNP3; and rectal temperature (p.m.), pulse rate (p.m.), Hb (g/dL), and N/L ratio at SNP4 and TLC at SNP5. Gene expression analysis revealed higher expression in less adapted animals with Madras Red < Magra < Chokla < Marwari expression pattern [corrected]. Predominant allele was found to be superior in most of the SNPs (SNP1-4) indicating the selection acting in directional manner (positive selection). Finally, it is concluded that TACCA haplotype combination of SNP1-SNP2-SNP3-SNP4-SNP5 might be of some selection advantage for the identification of animals more adaptable to heat stress.

Search for Neutrinoless Quadruple-β Decay of ^{150}Nd with the NEMO-3 Detector

We report the results of a first experimental search for lepton number violation by four units in the neutrinoless quadruple-β decay of ^{150}Nd using a total exposure of 0.19 kg yr recorded with the NEMO-3 detector at the Modane Underground Laboratory. We find no evidence of this decay and set lower limits on the half-life in the range T_{1/2}>(1.1-3.2)×10^{21}  yr at the 90% C.L., depending on the model used for the kinematic distributions of the emitted electrons.

The BiPo-3 detector

The BiPo-3 detector is a low radioactive detector dedicated to measuring ultra-low natural contaminations of ²⁰⁸Tl and ²¹⁴Bi in thin materials, initially developed to measure the radiopurity of the double β decay source foils of the SuperNEMO experiment at the μBq/kg level. The BiPo-3 technique consists in installing the foil of interest between two thin ultra-radiopure scintillators coupled to low radioactive photomultipliers. The design and performances of the detector are presented. In this paper, the final results of the ²⁰⁸Tl and ²¹⁴Bi activity measurements of the first enriched ⁸²Se foils are reported for the first time, showing the capability of the detector to reach sensitivities in the range of some μBq/kg.