TVnet: automated global analysis of tricuspid valve plane motion in CMR long-axis cines with residual neural networks for assessment of right ventricular function

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Clarendon Fund, John Fell Oxford University Press Research Fund, Oxford BHF Centre of Research Excellence (RE/18/3/34214), Alison Brading Memorial Graduate Scholarship in Medical Science, National Institute for Health Research Oxford Biomedical Research Centre, National Institutes of Health (R01HL144706).

Background

Right ventricular (RV) function evaluation is an integral part of comprehensive cardiac assessment, including for pulmonary hypertension, congenital heart disease and arrhythmogenic RV cardiomyopathy (ARVC) [1]. It is commonly assessed by measuring tricuspid annular plane systolic excursion (TAPSE) and peak systolic velocity (RV s’) on echocardiography [2]. However, it is highly sensitive to imaging window and small changes in the beam angle, limiting reliability [3]. Cardiovascular magnetic resonance (CMR) is the imaging gold-standard for assessing RV structure and function, and is highly reproducible. CMR can assess tricuspid valve (TV) motion using four-chamber (4Ch) and RV two-chamber (2Ch) cines, with high diagnostic performance when compared against single-plane analysis [4]. However, manual placement of the TV insertion points is highly time-consuming for routine clinical workflows. TVnet, a deep-learning framework for automatically tracking the TV in 4Ch cines [5] has been recently validated, but without the orthogonal plane (RV 2Ch) which is helpful to more reliably characterise TV motion.

Purpose

We further extend TVnet to automatically track RV 2Ch cines and derive analysis of global TV motion parameters (global TAPSE and RV s’) on par with expert level performance.

Methods

74 patients undergoing CMR (1.5T Siemens MR scanner) with 4Ch and RV 2Ch views were retrospectively included in this ethically-approved study. The patients had the following cardiovascular conditions: myocardial infarction (n=43), ARVC (n=28) and Takotsubo cardiomyopathy (n=3). The dual-stage deep-learning pipeline with a residual neural network backbone [5, 6] (Figure 1A) was trained using 69 patient datasets and 15 patients were randomly chosen for testing. The TVnet trained on 4Ch cines [5] was used to automatically annotate the 4Ch cines of the testing set for global analysis comparison. For manual reference, the software Segment [7] was used to manually annotate the TV insertion points in all imaging data (1,865 RV 2Ch images, 375 4Ch images). The global TAPSE and RV s’ were derived as the mean perpendicular motion from the end-diastolic plane from both chamber views (Figure 1B).

Results

TVnet achieved a fast processing accuracy (<1 second per cine) and successfully tracked the TV insertion points from the RV 2Ch cine with a plane tracking error of 0.08±0.83 mm. The integrated pipeline yielded an excellent clinical-metric agreement with the manual reference (Figure 2) for both global TAPSE (error=0.42±0.68 mm, ICC=0.95) and RV s’ (error=-0.10±0.71 cm/s, ICC=0.85).

Conclusion

TVnet demonstrated excellent performance in both tracking the TV insertion points in RV 2Ch cines and deriving global TAPSE and RV s’ compared to manual reference. TVnet can eventually provide a complete automatic inline analysis of TV plane motion for a fast, reliable and reproducible assessment of RV function in routine clinical workflows. (A) TVnet pipeline (B) Metric derivationCorrelation and Bland-Altman plots

[Analysis on the rationality of input and output of occupational health funds in an iron and steel enterprise]

Objective: To analyzes the various occupational health investment and occupational health output of a steel enterprise, and propose a reasonable occupational health investment plan for this enterprise. Methods: In march 2016, various occupational health input and output data of various branches of an iron and steel company in 2015 were collected, and the efficiency of occupational health inputs and outputs of each branch was evaluated using data envelopment analysis (DEA) , and the branches with non-optimal efficiency were adjusted to propose a reasonable occupational health investment plan. Results: Among the branch plants investigated by this steel company, the occupational health input-output efficiency values of ironmaking north plant, power plant, hot rolling plant and stainless steel plant were 1, while the occupational health input-output efficiency of gas making plant, cold rolling plant, metallurgical furnace charge plant, coking plant, ironmaking south plant and long product plant were not the best, and the cold rolling plant has the lowest efficiency value of 0.759. For the cold rolling plant, only the parameters of acid rolling plant satisfy α=1 and s(-)=0, s(+)=0, while the remaining four workshops do not meet. After adjusting the inputs of each part according to the parameters, the occupational health output of the remaining four workshops can reach 1.7044, 2.0238, 1.3152 and 1.2136 times of the current workshop, respectively. Adjustment plans for other branch factories with unreasonable investment structures are also presented in the corresponding tables. Conclusion: The occupational health investment structure of the ironmaking south plant and other branches in this steel enterprise is unreasonable, and the adjustment using data envelopment analysis can maximize the benefits of its occupational health output.

[Prevalence and risk factors of silicosis complicated with chronic obstructive pulmonary disease]

Objective: To explore the prevalence, clinical characteristics and risk factors of chronic obstructive pulmonary disease (COPD) in silicosis patients. Methods: In May 2021, a cross-sectional study was used to retrospectively include 329 silicosis patients first diagnosed in Beijing Chaoyang Hospital from January 1, 2007 to December 31, 2020. The demographic data, occupational history, chest imaging, pulmonary function and blood routine indicators of silicosis patients with COPD were analyzed, and the risk factors of silicosis with COPD were analyzed by multiple logistic regression. Results: There were 128 patients with silicosis complicated with COPD, and the overall prevalence rate was 38.9% (128/329) . Among them, 73.4% (94/128) were male and 33.6% (43/128) were heavy smokers; 33.6% (43/128) of patients were classified as gold 1, 37.5% (48/128) as gold 2, 25.0% (32/128) as gold 3, and 3.9% (5/128) as gold 4. Diagnostic age (OR=1.04, 95%CI=1.02~1.06, P<0.001) , cumulative smoking (OR=1.03, 95%CI=1.01~1.05, P=0.008) and silicosis stage III (OR=7.06, 95% CI=4.00-12.46, P<0.001) were risk factors for silicosis complicated with COPD. Conclusion: Diagnostic age, cumulative smoking volume and third stage of silicosis are the risk factors of silicosis patients with different degrees of COPD, which should be paid attention to in clinical treatment.

The effect of driving pressure-guided ventilation strategy on the patients with mechanical ventilation: a meta-analysis of randomized controlled trials

OBJECTIVE

The aim of this study was to evaluate the effect of driving pressure (DP) guided ventilation strategy on the patients with mechanical ventilation in the hospital.

MATERIALS AND METHODS

The articles published in PubMed, the Cochrane Library, the China National Knowledge Information (CNKI), Wei Pu, Wan Fang database and Web of Science from inception to September 2021 were retrieved. The Q test and the I² statistic were used to assess statistical heterogeneity. Risks ratios (RR) with 95% confidence intervals (CI) were calculated for mortality.

RESULTS

Seven studies (n=1,405 patients) were included. Five studies reported an adjusted Risk Ratio (RR) of mortality. Compared with the control group, the DP guided ventilation group was associated with a decreased mortality (RR 0.56; 95% confidence interval [CI], 0.39-0.79; p=0.001; I2 = 23%) using a fixed-effects model without significant heterogeneity. The control group had significantly higher driving pressure level than DP guided group (MD -3.03, 95%CI, -5.72 - -0.34, I2=100%, p=0.03); PaO2/FiO2 was significantly higher in DP guided group than in control group (MD 43.37; 95%CI, 12.58-74.15; I2=97%, p=0.006). There was no statistically significant difference in respiratory compliance, complications, platform pressure, duration of mechanical ventilation and the length of hospital stay between the DP guided group and the control group.

CONCLUSIONS

The results suggested that the driving pressure guided ventilation strategy could decrease the mortality and increase oxygenation index (OI). However, further high-quality randomized controlled trials (RCTs) are needed to verify the impact of driving pressure on mechanically ventilated patients.

Deciphering radiological stable disease to immune checkpoint inhibitors

BACKGROUND

'Stable disease (SD)' as per RECIST is a common but ambiguous outcome in patients receiving immune checkpoint inhibitors (ICIs). This study aimed to characterize SD and identify the subset of patients with SD who are benefiting from treatment. Understanding SD would facilitate drug development and improve precision in correlative research.

PATIENTS AND METHODS

A systematic review was carried out to characterize SD in ICI trials. SD and objective response were compared to proliferation index using The Cancer Genome Atlas gene expression data. To identify a subgroup of SD with outcomes mirroring responders, we examined a discovery cohort of non-small-cell lung cancer (NSCLC). Serial cutpoints of two variables, % best overall response and progression-free survival (PFS), were tested to define a subgroup of patients with SD with similar survival as responders. Results were then tested in external validation cohorts.

RESULTS

Among trials of ICIs (59 studies, 14 280 patients), SD ranged from 16% to 42% in different tumor types and was associated with disease-specific proliferation index (ρ = -0.75, P = 0.03), a proxy of tumor kinetics, rather than relative response to ICIs. In a discovery cohort of NSCLC [1220 patients, 313 (26%) with SD to ICIs], PFS ranged widely in SD (0.2-49 months, median 4.9 months). The subset with PFS >6 months and no tumor growth mirrored partial response (PR) minor (overall survival hazard ratio 1.0) and was proposed as the definition of SD responder. This definition was confirmed in two validation cohorts from trials of NSCLC treated with durvalumab and found to apply in tumor types treated with immunotherapy in which depth and duration of benefit were correlated.

CONCLUSIONS

RECIST-defined SD to immunotherapy is common, heterogeneous, and may largely reflect tumor growth rate rather than ICI response. In patients with NSCLC and SD to ICIs, PFS >6 months and no tumor growth may be considered 'SD responders'. This definition may improve the efficiency of and insight derivable from clinical and translational research.

Prediction of acute toxicity to Daphnia magna and interspecific correlation: a global QSAR model and a Daphnia-minnow QTTR model

Acute toxicity is an important basis for the assessment of hazardous chemicals, but currently there is a huge data gap in chemical toxicity information. The in silico Quantitative Structure Activity Relationship (QSAR) models can use the existing experimental data information to predict the missing chemical toxicity information data and thus reduce animal testing. In the present study, a global QSAR model for the prediction of acute Daphnia magna toxicity has been developed based on the five principles proposed by the Organization for Economic Co-operation and Development (OECD). Moreover, a Daphnia-minnow (referring specifically to the fathead minnow) Quantitative Toxicity-Toxicity Relationship (QTTR) prediction model has been developed based on the present study and our previous work on fathead minnow (Pimephales promelas). Both the QSAR and QTTR prediction models have good goodness-of-fit, robustness, and predictive ability. Finally, the acute toxicity mode of action (MOA) for fathead minnow and Daphnia magna was compared by toxicity ratio based on interspecies toxicity data. By comparison, Daphnia magna was found more sensitive to anilines and phosphorothioates than fathead minnow. The present models can fill the acute toxicity data gap and contribute to the chemicals risk assessment and priority setting.

[Two-dimensional equivalent mechanical modeling and finite element analysis of normal female pelvic floor system]

Objective: To construct the geometric model of the pelvic floor by a two-dimensional equivalent mechanics method, and to explore the effect of the shape and position of pelvic floor organs and tissues on the biomechanical properties of the pelvic floor under different abdominal pressure. Methods: A 28-year-old healthy and symmetrical married infertile female volunteer was included. The pelvic floor tissue was scanned in the supine position using a 3.0T magnetic resonance scanner (Philips Company, Holland). Based on the method of magnetic resonance imaging (MRI) two-dimensional parameter measurement and computer aided design, the geometric model and finite element model of the female pelvic floor were established, and the biomechanical characteristics of the pelvic floor support system under different abdominal pressure were analyzed. Results: In this study, four different working conditions of the pelvic floor force were simulated under 60, 99, 168, and 208 cmH₂O (1 cmH₂O=0.098 kPa) abdominal pressure loads. The trend was as follows: under the abdominal pressure load, the retrograde flexion of the uterus occurred, the cervical, the middle and upper vaginal segment and the levator anus muscle had the characteristic change of mechanical axial direction pointing to the sacrum and coccyx, and the deformation of the levator anus muscle in the horizontal direction was greater than that in the vertical direction. With the increase of the abdominal pressure, the maximum stress values of the pelvic floor whole system of healthy subjects under four different working conditions were 0.194 3, 0.389 6, 0.557 1, and 0.627 5 MPa, respectively, and the maximum displacement values were 10, 14, 21 and 25 mm, respectively. The maximum stress values of the cervical and vaginal middle and upper segment were 0.111 7, 0.161 8, 0.250 6, and 0.304 1 MPa, respectively, and the maximum displacement values were 3, 6, 9, and 11 mm, respectively. The maximum stress of the perineal body was 0.063 4, 0.119 6, 0.235 2, and 0.288 0 MPa, and the maximum displacement was 1, 2, 4, and 5 mm. The maximum stress values of the levator anus muscle were 0.194 3, 0.389 6, 0.557 1, and 0.627 5 MPa, and the maximum displacement values were 2, 4, 7, and 8 mm, respectively. The maximum stress and maximum displacement of pelvic organs increased with the increase of the abdominal pressure under different working conditions. The stress axial relationship of normal female pelvic floor was that the middle and upper segment of uterus and vagina mainly acted on the sacrococcyx and the levator anus muscle, and the lower vaginal segment acts on the perineal body. Conclusions: The two-dimensional equivalent mechanical modeling and finite element analysis of the female pelvic floor system can accurately reflect the biomechanical characteristics of the female pelvic floor, and the resultant stress direction of the pelvic organs points to the sacrum and coccyx. The sacrum and coccyx, levator anus and perineal body play important stress supporting roles in the pelvic floor system.

[The clinical value of oral robotic surgery in the treatment of oropharyngeal squamous cell carcinoma]

Objective: To explore the therapeutic effects of transoral robotic surgery (TORS) and traditional surgical modes in oropharyngeal squamous cell carcinoma (OPSCC). Methods: The clinicopathological data of patients with oropharyngeal squamous cell carcinoma treated at Sun Yat-sen University Cancer Center from 2010 to 2018 were retrospectively analyzed. 135 cases were treated with traditional surgery (non-TORS group), while 52 cases were treated with TORS (TORS group). The prognosis of the two groups of patients were analyzed by Kaplan-Meier method and Log rank test, the influencing factors were analyzed by Cox regression model. Results: The 2-year overall survival (OS, 94.2%) and 2-year progression-free survival (PFS, 93.8%) of patients in the TORS group were better than those in the non-TORS group (71.4% and 71.4%, respectively, P<0.05). The 2-year OS (93.3%) and 2-year PFS (92.8%) of TORS group patients in T1-2 stage were better than those of non-TORS group (73.1% and 72.8%, respectively, P<0.05). The 2-year OS (95.8%) and 2-year PFS (95.2%) of patients with stage Ⅰ to Ⅱ in the TORS group were not significantly different from those in the non-TORS group (84.1% and 83.9%, respectively, P>0.05). The 2-year OS (92.9%) and 2-year PFS rate (92.7%) of patients with stage Ⅲ to Ⅳ in the TORS group were better than those in the non-TORS group (64.7% and 63.9%, respectively, P<0.05). The 2-year OS (94.4%) of HPV-positive patients in the TORS group was not significantly different from that in the non-TORS group (83.3%, P=0.222). The 2-year OS of HPV-negative patients in the TORS group (94.1%) was significantly different from that in the non-TORS group (43.7%, P<0.001). HPV status was an independent prognostic factor (P=0.008). Conclusions: TORS has a better prognosis in the treatment of oropharyngeal squamous cell carcinoma compared with the traditional treatment methods. The patients with T1-T2 can achieve better survival benefits after TORS treatment. The HPV-positive OPSCC patients has a better prognosis than that of HPV-negative OPSCC patients, and regardless of HPV status, OPSCC patients in the TORS group could obtain a better survival prognosis.

[Status of HVPG clinical application in China in 2021]

Objective: The investigation and research on the application status of Hepatic Venous Pressure Gradient (HVPG) is very important to understand the real situation and future development of this technology in China. Methods: This study comprehensively investigated the basic situation of HVPG technology in China, including hospital distribution, hospital level, annual number of cases, catheters used, average cost, indications and existing problems. Results: According to the survey, there were 70 hospitals in China carrying out HVPG technology in 2021, distributed in 28 provinces (autonomous regions and municipalities directly under the central Government). A total of 4 398 cases of HVPG were performed in all the surveyed hospitals in 2021, of which 2 291 cases (52.1%) were tested by HVPG alone. The average cost of HVPG detection was (5 617.2±2 079.4) yuan. 96.3% of the teams completed HVPG detection with balloon method, and most of the teams used thrombectomy balloon catheter (80.3%). Conclusion: Through this investigation, the status of domestic clinical application of HVPG has been clarified, and it has been confirmed that many domestic medical institutions have mastered this technology, but it still needs to continue to promote and popularize HVPG technology in the future.

[Clinical epidemiological survey of primary liver cancer in Yunnan province from 2005 to 2014]

Objective: To investigate the clinical characteristics and changing trends of primary liver cancer in Yunnan province from 2005 to 2014, in order to provide theoretical basis for the prevention and treatment of liver cancer in this region. Methods: A retrospective survey was used to select inpatient cases of liver cancer who were initially diagnosed and treated in our hospital from 2005 to 2014 with simple random sampling. Patients socio-demographic and clinicopathological characteristics were extracted by a unified and standardized questionnaire, and the data were statistically analyzed. Results: A total of 1000 cases with liver cancer were included, aged (53.2±11.2) years, with a male-to-female ratio of 5.99/1.00. There was no significant change in the gender and age composition ratio of patients in the past 10 years. The proportion of patients with lower education level (primary or junior high school) were increased from 21.8% to 23.4%, and the proportion of patients with relatively higher education level were decreased from 58% to 38.2% (P<0.001). Smokers and non-smokers patients were decreased and increased from 58.8% to 44.4%, and 41.2% to 55.6% (P<0.001). The proportion of drinker patients were decreased from 46.4% to 35.2%. The proportion of patients with advanced liver cancer (stage C and D) were increased, while the proportion of patients with stage A and B showed a downward trend (P<0.001). The proportion of HBsAg-positive patients showed an upward trend, that is, rising from 69% in 2005 to 82% in 2014 (P=0.043). The proportion of HBeAg-positive patients showed a steady trend (P=0.008). The use rate of ultrasound examination in patients with liver cancer were decreased from 91.0% to 58.0% (P=0.001), while the use rate of computed tomography (CT), MRI, and PET/CT examinations were increased from 81.0% to 84.0% (P=0.05), 0 to 22% (P<0.001), and 0 to 3% (P=0.026) between 2005 to 2014. The proportion of surgical patients were increased (P=0.005), but the proportion of interventional patients did not change significantly (P=0.590). Surgery and interventional therapy were the most common treatment methods, and the proportion of patients treated with surgery over the past 10 years showed an upward trend (P=0.005), while the proportion of interventional therapy remained at a high level with no significant change (P=0.590). Conclusion: In Yunnan province, the incidence of liver cancer increases with age, and the proportion of male with liver cancer is almost six times that of women. Moreover, the low positive rate of alpha-fetoprotein levels and advanced clinical stage in this region are presently the main challenges against the liver cancer prevention and treatment. The application scope of CT, magnetic resonance imaging, PET-CT and other examination methods has gradually expanded, but the treatment methods are still mainly surgery and interventional therapy.

Expression and distribution of erythropoietin, vascular endothelial growth factor (VEGF) and VEGF receptor 2 in small intestine of yaks at different ages

BACKGROUND

This study aimed to detect the expression and distribution of vascular endothelial growth factor (VEGF), VEGF receptor 2 (VEGFR-2), and erythropoietin (EPO) proteins in small intestinal tissues of 50-day-old, newborn, and adult yaks. The results provide basic data for the study of the relationship between adaptability and age of plateau yak.

MATERIALS AND METHODS

Small intestine tissues from healthy adult, 50-day-old, and newborn yak were collected and embedded in paraffin sections. Histological features were observed by haematoxylin and eosin staining. The expression of VEGF, VEGFR-2, and EPO proteins were detected by immunohistochemical staining.

RESULTS

Immunohistochemical results showed that of the expression VEGF, VEGFR-2, and EPO were detected in the small intestinal villi of yaks at all ages. The EPO expression level in the jejunum and duodenal villous epithelial cells of newborn yaks was significantly higher than that of 50-day-old and adult yaks. The EPO expression level in ileum villous epithelial cells of 50-day-old yaks was significantly higher than that of newborn and adult yaks. VEGF expression in newborn yak ileum and jejunum epithelial cells of the intestinal villus were significantly higher than in the 50-day-old and adult. In the 50-day-old yaks, the duodenal intestinal villus epithelial cells expression levels were higher than in the adult and newborn yaks. The expression level of VEGFR-2 in the ileum, jejunum and duodenal villous epithelial cells of 50-day-old yak was significantly higher than in that of adult and newborn yak.

CONCLUSIONS

The expression and distribution characteristics of EPO, VEGF, and VEGFR-2 in yak intestinal tissues of different ages indicate that these proteins may be involved in the physiological regulation of yak intestines in hypoxic environments. It may be an important regulatory protein in yak adaptation to a high altitude and low oxygen environment.

Investigating novel roles for nesprin-1 and the LINC complex in Dilated Cardiomyopathy

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation

Cardiomyopathies are an important cause of heart failure and sudden cardiac death. Recent studies have demonstrated the importance of the "passive" mechanical components of cardiomyocytes (CMs) as new causes for dilated cardiomyopathy (DCM). Nesprin-1/-2 are highly expressed in skeletal and cardiac muscle and together with SUN (Sad1p/UNC84)-domain containing proteins form the LInker of Nucleoskeleton and Cytoskeleton (LINC) complex at the nuclear envelope (NE), which, in association with lamin A/C and emerin, mechanically couples the nucleus to the cytoskeleton. We have recently identified novel nesprin-1 mutants in  DCM patients, which cause LINC complex disruption, leading to defects in nuclear organisation and myogenesis in vitro. We aim to investigate mechanisms through which these mutations lead to DCM. Therefore, we have generated a nesprin-1 mutant R8253Q knock-in (KI) mouse line (equivalent to human SYNE1 R8272Q) as the first clinically relevant animal model. 2. R8272Q is in close proximity to the binding regions to microtubule (MT) associated proteins kinesin light chain-1/2 and Akap6 at the nuclear envelope, which is potentially in involved in MT organization. Preliminary mouse echocardiography data showed significantly reduced thickness of left ventricle (LV) posterior wall in diastole, and reduced % ejection fraction in the KIs at 15 weeks after birth, suggesting LV dysfunction and a tendency of DCM. Immunofluorescence (IF) of isolated adult cardiomyocytes (ACM) from KI mice showed perinuclear MT localization was significantly reduced, KLC-1/2 and AKAP6 were mislocalized from the NE and altered nuclear positioning. Therefore, we propose to investigate novel roles of nesprin-1 and the LINC complex in cardiomyocyte mechanotransduction using this KI model to explore roles of  nesprin-1 in microtubule organization, nuclear positioning, and CM homeostasis, which will yield insights into signalling leading to DCM and heart failure as well as inform strategies for translational approaches.

Optimization of environmental factors in a dual in vitro biofilm model of Candida albicans-Streptococcus mutans

The biofilm formation of Streptococcus mutans-Candida albicans is an important virulence factor for dental caries. The purpose of this study was to determine the effect of some environmental conditions on the biofilm formation like inoculation concentration, temperature, sugar, amino acid, metal ions and saliva, and then establish a persistent in vitro biofilm model for further research. Based on the single factor experiment, the factors participating in the biofilm formation including sugar, inoculation concentration, and saliva increased the biofilm mass, while amino acid, metal ions, temperatures reduced biofilm mass. Optimal conditions for biofilm formation were the inoculation dosage of S. mutans and C. albicans of 10⁸ and 10⁷ , respectively, the addition of 0·3 g l^-1 sucrose and sterile saliva. These results contribute to a deep understanding of the factors involved in oral biofilm formation of the important cariogenic pathogen S. mutans and the opportunistic pathogen C. albicans to study better for biofilm and promote the design of new therapeutic approaches. The present research also provides a model for evaluating the therapeutic potential for drugs in the future.

Le déficit en interféron de type I n’altère pas la réponse lymphocytaire B mémoire contre le SARS-CoV-2 après vaccination par ARNm

Introduction

Les vaccins à ARN messagers ont joué un rôle majeur dans la lutte contre la pandémie de SARS-CoV-2 grâce à une excellente efficacité et sécurité clinique. Ces vaccins ont été développés suite à des années de recherche fondamentale, dont l’une des étapes cruciales a été de remplacer l’uridine de l’ARNm par de la 1-méthyl-pseudo-uridine afin d’éviter la reconnaissance par les récepteurs de l’immunité innée, notamment le toll-like-receptor (TLR) 7. Une hypothèse, très fréquemment défendue mais jamais étayée expérimentalement, est que cet ARN modifié garde une activité immunostimulatrice à bas bruit permettant la production d’interféron de type I, agissant comme un adjuvant du vaccin. Les interférons de type I sont des cytokines antivirales essentielles et les patients ayant un déficit dans les voies de l’interféron de type I sont à haut risque de COVID-19 sévère. Dans ce travail, nous avons analysé la réponse lymphocytaire B au vaccin à ARNm de patients présentant l’absence de signalisation par les interférons de type I. Ceci nous a permis de savoir si les vaccins par ARNm permettaient d’établir une réponse lymphocytaire B robuste en l’absence d’interféron de type I.

Patients et méthodes

Nous avons constitué trois cohortes de patients (i) des patients avec des déficits génétiques sur les voies de l’interféron de type I : 2 patients avec une mutation homozygote d’IRF7 (facteur de transcription responsable de la production d’interférons de Type I, notamment en aval de TLR7) et un patient avec une déficit hémizygote de TLR7 (ii) des patients ayant des auto-anticorps neutralisant les interférons alpha et oméga, dans le cadre d’une polyendocrinopathie auto-immune de type I (APS-1, n = 14) (iii) des patients ayant des auto-anticorps neutralisant les interféron, associés à l’âge, une entité récemment décrite et particulièrement fréquente chez les sujets âgés (n = 8). Ces sujets ont été comparés à 29 contrôles sains. Tous étaient naïfs du COVID-19 et ont reçu 2 doses de vaccin à ARNm (BNT162n2 ou mRNA1273). Les patients ont été prélevés à différents point de temps, dans les 3 premiers mois et entre 3 et 7 mois après la seconde dose. La réponse sérologique a été évaluée par ELISA anti-IgG et IgA RBD (receptor binding domain de la Spike) et la neutralisation sérique a été testée in vitro contre le D614G-SARS-CoV-2. Les lymphocytes B (LB) mémoires CD19 + IgD-CD27± spécifiques du RBD ont été analysés en cytométrie en flux et triés en cellule unique pour séquençage des régions variables de la chaîne lourde de l’immunoglobuline.

Résultats

La réponse sérologique anti-RBD IgG et IgA était comparable aux temps précoces et tardifs de la réponse vaccinale, évoluant de façon similaire chez les patients déficients en interféron de type I et les sujets sains. La capacité de neutralisation des sérums contre le SARS-CoV-2 était également identique dans tous les groupes, et corrélait fortement avec le taux d’IgG anti-RBD, suggérant que le RBD était également la cible de la réponse neutralisante chez les patients déficients en interféron de type I. Des LB mémoires circulants spécifiques du RBD étaient retrouvés dans toutes les cohortes de patients déficients en interféron de type I au cours des 3 mois suivant la vaccination. Ceux-ci se maintenaient dans le temps et étaient encore présents entre 3 et 7 mois après la vaccination (0,18 % des LB IgD-CD27+ chez les sujets sains, 0,24 % chez les sujets avec déficit génétiques, 0,16 % chez les APS-1 et 0,26 % chez les AAB, pas de différence statistiquement significative). Le séquençage de la chaîne lourde des régions variables de l’immunoglobuline des LB mémoires spécifiques du RBD révélait l’accumulation progressive des mutations jusqu’à 7 mois chez les sujets sains, témoignant d’une réaction des centres germinatifs permettant la maturation d’affinité et la génération de lymphocytes B mémoires à longue durée de vie. Chez les patients IRF7 déficients, les LB mémoires spécifiques du RBD acquerraient progressivement des mutations de M1 à M6, et les LB mémoires spécifiques du RBD de patients TLR7 et APS-1 arboraient un nombre élevé de mutation dès M4, témoignant que même en l’absence de réponse à l’interféron de type I, le vaccin permettait la génération des LB mémoire issus des centres germinatifs, comme chez les sujets sains. Enfin, des clones partagés étaient retrouvés entre les sujets sains et les patients déficient en interféron de type I témoignant d’une réponse qualitativement normale.

Conclusion

Notre travail apporte des données rassurantes sur la vaccination de ces patients à haut risque de forme de grave de COVID-19 et suggère que l’ARNm contenu dans les vaccins n’a pas de rôle adjuvant intrinsèque.

Evaluation of the efficacy of a novel phytase in short-term digestibility and long-term egg production studies with laying hens

Three independent trials were conducted to evaluate the efficacy of a novel phytase in laying hens. Trial 1 used a total of 90 laying hens (Lohmann Brown, 33-wk-old) fed either a negative control (NC) diet with 0.09% non-phytate P (NPP) or NC supplemented with 187.5 or 375 FYT phytase/kg feed for 4 d before collection of excreta and ileal digesta to measure ileal digestibility and retention of Ca and P. In trial 2 and 3, a total of 108 laying hens (Hy Line Brown, 25-wk-old) and 360 hens (Lohman Brown, 25-wk-old) were used, respectively. In both trials, the hens were randomly assigned to 3 dietary treatments: NC with 0.1% NPP, positive control (PC) and NC plus 187.5 FYT phytase/kg feed, the experimental diets were fed for 12 wk, and egg production and bone mineralization were measured. The results showed that the ileal digestibility of P increased both linearly (P = 0.012) and quadratically (P = 0.01) with increasing supplementation of phytase in trial 1. In trial 2, phytase supplementation significantly improved egg production, egg weight, and feed conversion ratio and reduced the percentage of broken eggs during the overall trial duration compared with NC. In trial 3, phytase significantly improved egg production, egg weight, and feed intake and reduced the percentage of broken eggs during the entire trial duration. In addition, percentage and weight of bone Ca and P increased significantly with added phytase. In trial 2 and 3, there was no significant difference between PC and the phytase treatment. In conclusion, the novel phytase significantly increased the ileal digestibility of P in a short-term digestibility study and improved egg production and bone mineralization in a 12-wk laying cycle. Ileal digestibility of P rather than P retention in short-term digestibility studies as well as egg production and whole tibia mineralization in long-term studies should be measured to demonstrate the efficacy of phytase in laying hens.