Les inhibiteurs du système rénine-angiotensine et la mortalité par COVID-19 : une cohorte prospective de 1160 patients hypertendus, et revue de littérature

Introduction

L’influence d’un traitement chronique par inhibiteurs du système rénine-angiotensine (ISRA) chez les patients infectés par la COVID-19 a fait l’objet de nombreuses études en 2020 avec des résultats controversés, suggérant tantôt l’interruption du traitement au long cours, ou au contraire un effet protecteur du traitement. Nos objectifs étaient :

– d’étudier la mortalité associée à un traitement chronique par ISRA chez des patients hospitalisés pour une infection par le SARS-CoV-2 en France ;

– les raisons expliquant les résultats discordants dans la littérature.

Méthodes

Nous avons sélectionné les sujets hypertendus inclus dans l’étude nationale prospective de 3512 patients hospitalisés avec COVID-19 (cohorte French-COVID) jusqu’au 30 juin 2020. L’exposition était définie par la prescription d’inhibiteurs de l’enzyme de conversion ou antagonistes des récepteurs de l’angiotensine II avant hospitalisation. Des modèles de Cox avec pondérations basées sur le score de propension ont permis d’estimer des hazard ratios (HR) de mortalité à 30 jours du diagnostic de COVID-19 chez les sujets exposés aux ISRA par rapport aux non exposés. Notre revue de la littérature s’est intéressée aux méthodes (plan expérimental, population, exposition, critères de jugement, méthodes statistiques) et aux résultats des études observationnelles publiées étudiant le rôle pronostique des ISRA dans la COVID-19.

Résultats

Nous avons analysé 1160 patients hypertendus ; 719 (62 %) hommes, 777 (67 %) âgés de plus de 65 ans. Les principales comorbidités étaient le diabète (n = 416, 36 %), les maladies cardiaques (n = 401, 35 %) et l’obésité (n = 340, 29 %) ; 705 (61 %) patients étaient sous oxygène dans les deux jours suivant l’admission. Nous avons enregistré 135 (11,6 %) décès dans les 30 jours. Aucune association entre l’exposition chronique aux ISRA et la mortalité (HR non ajusté = 1,13, IC95 % [0,8–1,6] ; HR pondéré sur l’IPT = 1,09 [0,86–1,39] ; HR pondéré sur le SMR = 1,08 [0,79–1,47]) n’a été mise en évidence. Notre revue de littérature a retrouvé 51 études individuelles : 31 chez des patients hypertendus, et 39 chez des patients hospitalisés. Parmi ces dernières, 25/39 ont étudié l’effet du traitement chronique par ISRA avant l’hospitalisation, 11/39 ont étudié l’effet de l’exposition aux ISRA pendant le séjour, et pour 4/39 la temporalité de l’exposition était indéfinie. Un risque augmenté de mortalité associé à l’exposition aux ISRA était fréquemment rapporté dans les études menées dans des populations peu sélectionnées (non restreintes aux hypertendus) ou avec un ajustement inapproprié, généralement expliqué par un biais d’indication. A contrario, une diminution significative de la mortalité associée à l’exposition aux ISRA était le plus souvent rapportée dans des études où l’exposition était définie par le traitement ISRA au cours de l’hospitalisation, expliquée par un biais de causalité inverse et un biais d’immortalité.

Conclusion

Nos résultats ne montrent pas d’association significative entre la prise chronique d’ISRA et la mortalité chez des patients hypertendus hospitalisés pour COVID-19, en accord avec les recommandations des sociétés savantes qui recommandent la poursuite de ces traitements malgré la pandémie. La question d’introduire ces traitements en cours d’hospitalisation est en cours d’évaluation dans des essais randomisés.

Score for pulmonary tuberculosis in patients with clinical presumption of tuberculosis in a low-prevalence area

OBJECTIVES: To develop a diagnostic predictive model for the identification of patients with presumptive pulmonary tuberculosis (PTB) at high risk for active disease and those requiring nucleic acid amplification (NAAT) testing and/or preventive respiratory isolation in low-incidence, high-income countries.DESIGN: A 1:1 case-control study was conducted in consecutive immunocompetent patients with presumed PTB hospitalised between 2009 and 2012 in Paris, France. Cases were defined as individuals with culture-confirmed PTB, regardless of smear result. Those with presumed PTB and three smear- and culture-negative samples were selected as controls. A score was derived using conditional logistic regression. Internal validity of the score was assessed using the bootstrap method.RESULTS: A total of 354 patients were included in the analysis (177 cases, 177 controls). Among the 177 cases, 74 (42%) were smear-negative but culture-positive. Factors independently associated with PTB were age <50 years (adjusted OR [aOR] 4.7, 95%CI 1.8–12), diabetes (aOR 3.2, 95%CI 1.1–9.8), absence of cough with or without sputum (aOR 3.7, 95%CI 1.7–8.3), fever >15 days (aOR 3.5, 95%CI 1.3–9.5), apical infiltration without cavity (aOR 3.4, 95%CI 1.4–8.5) and cavitation or miliary pattern (aOR 19.7, 95%CI 7.6–51.1). Score C-index was 0.84 (95%CI 0.79–0.88). Calibration for the overall population (P = 0.770) and in smear-negative patients (P = 0.980) was appropriate. A score of 3.3 had 90% sensitivity, 50% specificity and 79% (IQR 28–95) median probability of PTB.CONCLUSIONS: This score could be used to build an algorithm to determine the need for respiratory isolation and/or NAAT use in PTB disease.

Effect of appendicectomy on colonic inflammation and neoplasia in experimental ulcerative colitis

Background

Ulcerative colitis (UC) promotes cancer, and can be ameliorated by early appendicectomy for appendicitis. The aim of the study was to explore the effect of appendicectomy on colitis and colonic neoplasia in an animal model of colitis and a cohort of patients with UC.

Methods

Five-week old IL10/Nox1DKO mice with nascent colitis and 8-week-old IL10/Nox1DKO mice with established colitis underwent appendicectomy (for experimental appendicitis or no appendicitis) or sham laparotomy. The severity and extent of colitis was assessed by histopathological examination, and a clinical disease activity score was given. From a cohort of consecutive patients with UC who underwent colectomy, the prevalence of appendicectomy and pathological findings were collected from two institutional databases.

Results

Appendicectomy for appendicitis ameliorated experimental colitis in the mice; the effect was more pronounced in the 5-week-old animals. Appendicectomy in the no-appendicitis group was associated with an increased rate of colonic high-grade dysplasia (HGD) or cancer compared with rates in sham and appendicitis groups (13 of 20 versus 0 of 20 and 0 of 20 respectively; P &lt; 0·001). Fifteen of 232 patients who underwent colectomy for UC had previously had an appendicectomy, and nine of these had colonic cancer or HGD. Thirty (13·8 per cent) of 217 patients with the appendix in situ had colonic neoplastic lesions. Multivariable analysis showed that previous appendicectomy was associated with colorectal neoplasia (odds ratio 16·88, 95 per cent c.i. 3·32 to 112·69).

Conclusion

Appendicectomy for experimental appendicitis ameliorated colitis. The risk of colorectal neoplasia appeared to increase following appendicectomy without induced appendicitis in a mouse model of colitis, and in patients with UC who had undergone appendicectomy.

Lack of clinical or haemodynamic rebound after abrupt interruption of beta-blockers in patients with cirrhosis

BACKGROUND

Beta-blockers may have to be interrupted in patients with cirrhosis. The concept of a rebound after interruption of beta-blockers is based on an animal study and on isolated case reports of variceal bleeding.

AIM

To determine if a rebound occurs in patients with cirrhosis following abrupt interruption of beta-blockers.

METHODS

We prospectively included all consecutive patients with cirrhosis undergoing right heart and hepatic vein catheterisation. Four groups were defined: 'no beta-blockers' including patients not receiving beta-blockers; '≤1 day', '2-3 days' and '≥4 days' classified according to the time patients had interrupted beta-blockers before catheterisation. Results were expressed as median (interquartile range).

RESULTS

A total of 150 patients were included. Among the 25 patients in the groups '2-3 days' and '≥4 days', median duration of beta-blockers interruption was 4 (3-6) days. No gastrointestinal bleeding occurred during that period, nor during the following month. Hepatic venous pressure gradient was not different among patients in usually treated with beta-blockers. After adjustment, beta-blockers interruption was not associated with hepatic venous pressure gradient. Cardiac index was higher in the '≥4 days' group [4.6 L/min/m(2) (3.5-5.1)] than in the '≤1 day' group [3.4 (2.6-4.0); P = 0.001] or in the '2-3 days' group [3.1 (2.7-3.7); P = 0.007], but not different from the 'no beta-blockers' group.

CONCLUSIONS

Abrupt interruption of beta-blockers is associated neither with an apparent increase in the risk of variceal bleeding nor with a haemodynamic rebound. Thus, interruption of beta-blockers in patients with cirrhosis may not require particular dosing or surveillance.

Performance and impact of a rapid method combining mass spectrometry and direct antimicrobial susceptibility testing on treatment adequacy of patients with ventilator-associated pneumonia

Inappropriate antibiotic therapy in ventilator-associated pneumonia (VAP) is associated with increased mortality. Using broad-spectrum antibiotics for 48 h until the results of conventional cultures and antimicrobial susceptibility testing (AST) are available, may promote the emergence of drug-resistant bacteria. Performing AST directly on clinical respiratory samples would hasten the process by at least 24 h. Here, we analysed the diagnostic performance of a rapid method combining mass spectrometry and direct AST (DAST), and compared it with the conventional method (mass spectrometry with conventional AST (CAST)). Additionally, we assessed its potential impact on antimicrobial use in patients. Over a period of 18 months, the two methods were performed on 85 bronchoalveolar lavages obtained from intensive care unit patients with suspected VAP, and in which Gram-negative bacilli were observed on direct examination. Only the CAST results were reported to the clinicians. DAST produced useable results in 85.9% of the patients. The sensitivity and negative predictive values of DAST were 100% for all antibiotics tested, except gentamicin (97.1%, (95% CI 93.3-101) and 97.4% (93.7-101), respectively) and amikacin (88.9% (81.7-96.1) and 96.4% (92.1-100.7), respectively), compared with CAST. Specificity and positive predictive values ranged from 82.9 (74.2-91.5) to 100%, and from 86.4 (78.5-94.2) to 100%, respectively. If the DAST results had been reported to the clinicians, treatment could have been optimized 24 h earlier in 35/85 (41.2%) patients, with 17 carbapenem patient-days saved. Overall, routine use of the DAST method could help optimize earlier antibiotic treatment in patients with suspected VAP.

Clinical spectrum and outcomes of patients with encephalitis requiring intensive care

BACKGROUND AND PURPOSE

Our aim was to characterize the clinical profile, temporal changes and outcomes of patients with severe encephalitis.

METHODS

A retrospective cohort study was conducted on adult patients with encephalitis admitted to the medical intensive care unit (ICU) of a university hospital over a 20-year period. Patients' characteristics and outcomes were compared between two 10-year periods: (i) 1991-2001 and (ii) 2002-2012. Multivariate logistic regression was used to analyze factors associated with a poor outcome, as defined by a modified Rankin scale (mRS) score of 4-6 (severe disability or death) 90 days after admission.

RESULTS

A total of 279 patients were studied. Causes of encephalitis were infections (n = 149, 53%), immune-mediated causes (n = 41, 15%) and undetermined causes (n = 89, 32%). The distribution of causes differed significantly between the two periods, with an increase in the proportion of encephalitis recognized to be of immune-mediated causes. At day 90, 208 (75%) patients had an mRS = 0-3 and 71 (25%) had an mRS = 4-6. After adjustment for functional status before admission, the following parameters were independently associated with a poor outcome: coma [odds ratio (OR) 7.09, 95% confidence interval (95% CI) 3.06-17.03], aspiration pneumonia (OR 4.02, 95% CI 1.47-11.03), a lower body temperature (per 1 degree, OR 0.72, 95% CI 0.53-0.97), elevated cerebrospinal fluid protein levels (per 1 g/l, OR 1.55, 95% CI 1.17-2.11) and delayed ICU admission (per 1 day, OR 1.04, 95% CI 1.01-1.07).

CONCLUSIONS

Indicators of outcome in adult patients with severe encephalitis reflect both the severity of illness and systemic complications. Our data suggest that patients with acute encephalitis may benefit from early ICU admission.

US appearance of partial-thickness supraspinatus tendon tears: Application of the string theory. Pictorial essay

The supraspinatus tendon is composed of 5 different layers consisting of intertwining bundles. On a front portion of the tendon, the layers become coated bundles which insert on the trochanter. At the insertion, the superficial or bursal surface of the tendon corresponding to the tendon fibers in contact with the subacromial bursa can be distinguished from the deep surface corresponding to the fibers in contact with the glenohumeral joint. A tendon tear may involve partial or total disruption of the tendon fibers and is called full-thickness tear if it affects the entire tendon, and partial-thickness tear if it involves only part of the tendon. Partial-thickness tears of the supraspinatus tendon include lesions of the superficial, deep and central surface or tendon delamination.A contrast enhanced examination requires injection of contrast agent into the joint (arthrography followed by computed tomography (CT) or magnetic resonance imaging (MRI)) to study the deep surface, and injection into the subacromial bursa (bursography followed by CT) to study the superficial surface. MRI and ultrasound (US) examination allow the study of these different tendon layers without the use of contrast agent (which is not possible at CT).

An interdisciplinary approach to investigate the impact of cobalt in a human keratinocyte cell line

Since in nuclear power plants, risks of skin contact contamination by radiocobalt are significant, we focused on the impact of cobalt on a human cutaneous cell line, i.e. HaCaT keratinocytes. The present paper reports an interdisciplinary approach aimed at clarifying the biochemical mechanisms of metabolism and toxicity of cobalt in HaCaT cells. Firstly, a brief overview of the used instrumental techniques is reported. The following parts present description and discussion of results concerning: (i) toxicological studies concerning cobalt impact towards HaCaT cells (ii) structural and speciation fundamental studies of cobalt-bioligand systems, through X-ray absorption spectroscopy (XAS), ab initio and thermodynamic modelling (iii) preliminary results regarding intracellular cobalt speciation in HaCaT cells using size exclusion chromatography/inductively coupled plasma-atomic emission spectroscopy (SEC/ICP-AES) and direct in situ analysis by ion beam micropobe analytical techniques.

A comparison of cellular irradiation techniques with alpha particles using the Geant4 Monte Carlo simulation toolkit

A comparison of three cellular irradiation techniques using the Monte Carlo simulation toolkit Geant4 is presented in this paper. They involve electrodeposited source of alpha particle-emitting radionuclides, random classical alpha beam irradiation and single cell targeted irradiation using a focused alpha microbeam line. The simulation allows the calculation of hit distributions among the cellular population as well as the absorbed dose for two typical cellular geometries.

Promoter sequences involved in transforming growth factor beta1 gene induction in HaCaT keratinocytes after gamma irradiation

Transforming growth factor beta 1 (TGFB1) is a cytokine involved in the development of both acute and late cutaneous radiation syndromes. We previously demonstrated that ionizing radiation induces TGFB1 expression in vivo in pig skin within a few hours. The purpose of the present study was to develop an in vitro human model to identify the mechanisms of this early activation. Accordingly, human HaCaT keratinocytes were irradiated with a single dose of 20 Gy. First, radiation-induced TGFB1 overexpression was checked at both the transcriptional and transductional levels in HaCaT cells. Then electrophoretic mobility shift assays (EMSA) and transient transfection with various TGFB1 promoter constructs were used to identify the sequences involved in regulating this promoter. EMSA analysis showed the induction of nuclear protein binding activity by gamma irradiation to the -365 AP1 sequence (TGTCTCA), suggesting the involvement of AP1 sequences in the regulation of TGFB1 transcription. In gene reporter assays, maximal TGFB1 promoter activation was found for the longest construct, which contains two AP1 sequences. However, assays with constructs including deletions showed that these two AP1 sequences were not sufficient to confer TGFB1 inducibility. These results showed for the first time, to our knowledge, that transcriptional regulation is involved in radiation-induced activation of TGFB1 gene expression.

Antifibrotic action of Cu/Zn SOD is mediated by TGF-beta1 repression and phenotypic reversion of myofibroblasts

Skin fibrosis is characterized by the proliferation and accumulation of activated fibroblasts called myofibroblasts. They exhibit specific cytoskeletal differentiation, overexpress the fibrogenic cytokine TGF-beta1, synthesize excess extracellular matrix compounds and exhibit a depleted antioxidant metabolism. Recently, SOD was successfully used as an antifibrotic agent in vivo, thus challenging the postulate of established fibrosis irreversibility. We postulated that myofibroblasts could be a direct target for this therapeutic effect. To test this hypothesis, we used three-dimensional co-culture models of skin, in which specific phenotypes of normal fibroblasts versus myofibroblasts are retained. These 3-D models were treated with liposomal and carrier-free Cu/Zn SOD, and examined for their effects on cell number, cell death, and phenotypic differentiation. The results show that SOD did not induce myofibroblast cell death, whereas it significantly reduced TGF-beta1 expression, thus demonstrating that SOD might be proposed as a potent antagonist of this major fibrogenic growth factor. We also found that SOD significantly lowered the levels of the myofibroblast marker alpha-sm actin, of beta-actin, and of the extracellular matrix components alpha1(I) collagen and tenascin-C. In conclusion, our results suggest that SOD antifibrotic action occurred in vitro through the reversion of myofibroblasts into normal fibroblasts.

Histopathological and cellular studies of a case of cutaneous radiation syndrome after accidental chronic exposure to a cesium source

This study was designed for the histopathological, cellular and biochemical characterization of a skin lesion removed surgically from a young male several months after accidental exposure to cesium-137, with an emphasis on expression of transforming growth factor beta1 (TGFB1) and tumor necrosis factor alpha (TNFA) and the occurrence of apoptosis. Under a hypertrophic epidermis, a highly inhomogeneous inflammatory dermis was observed, together with fibroblastic proliferation in necrotic areas. Immunostaining revealed overexpression of TGFB1 and TNFA inside the keratinocytes of the hypertrophic epidermis as well as in the cytoplasm of the fibroblasts and connective tissue of the mixed fibrotic and necrotic dermis. Inside this dermis, the TUNEL assay revealed areas containing numerous apoptotic fibroblasts next to areas of normal viable cells. Overexpression of TGFB1 was found in the conditioned medium and cellular fractions of both hypertrophic keratinocytes and fibrotic fibroblasts. This overexpression lasted for at least three passages in tissue culture. The present observations were consistent with the central role of TGFB1 in the determination of chronic radiation-induced damage to the skin and a significant involvement of TNFA. In addition, programmed cell death appeared to take place during the remodeling of the mixed fibrotic and necrotic tissue.

Coactivation of AP-1 activity and TGF-beta1 gene expression in the stress response of normal skin cells to ionizing radiation

Activation of the AP-1 transcription factor and TGF-beta1 growth factor by ionizing radiation was studied both in vivo in pig skin, and in vitro in human fibroblasts and keratinocytes. Three and 6 h after irradiation, the Fos and Jun proteins and their binding activity to an AP-1 consensus sequence were strongly induced by high doses of gamma-rays. c-Fos, c-Jun and JunB proteins were found to be present in gel-shift complexes by probing with specific antibodies. Both keratinocytes and fibroblasts exhibited heightened AP-1 activity following irradiation. As we previously found that TGF-beta1 is involved in the development of skin lesions induced by radiation, TGF-beta1 gene expression was also examined. Two and 6 h after irradiation, the levels of TGF-beta1 transcripts were increased in skin. By immunostaining, TGF-beta1 protein levels were found to be increased in fibroblasts, keratinocytes and endothelial cells. As the TGF-beta1 promoter contains AP-1 binding sites, the relation between AP-1 activity and TGF-beta1 induction was addressed. The -365 TGF-beta1 promoter fragment, which contains a high affinity AP-1 site, exhibited increased binding to Jun and Fos proteins following irradiation. These results suggest that stress-inducible TGF-beta1 expression is mediated by the activation of AP-1 transcription factor.

Subcellular distribution of carbonic anhydrase in Solanum tuberosum L. leaves: characterization of two compartment-specific isoforms

The intracellular compartmentation of carbonic anhydrase (CA; EC 4.2.1.1), an enzyme that catalyses the reversible hydration of CO2 to bicarbonate, has been investigated in potato (Solanum tuberosum L.) leaves. Although enzyme activity was mainly located in chloroplasts (87% of total cellular activity), significant activity (13%) was also found in the cytosol. The corresponding CA isoforms were purified either from chloroplasts or crude leaf extracts, respectively. The cytosolic isoenzyme has a molecular mass of 255,000 and is composed of eight identical subunits with an estimated Mr of 30,000. The chloroplastic isoenzyme (Mr 220,000) is also an octamer composed of two different subunits with Mr estimated at 27,000 and 27,500, respectively. The N-terminal amino acid sequences of both chloroplastic CA subunits demonstrated that they were identical except that the Mr-27,000 subunit was three amino acids shorter than that of the Mr-27,500 subunit. Cytosolic and chloroplastic CA isoenzymes were found to be similarly inhibited by monovalent anions (Cl-, I-, N3- and NO3-) and by sulfonamides (ethoxyzolamide and acetozolamide). Both CA isoforms were found to be dependent on a reducing agent such as cysteine or dithiothreitol in order to retain the catalytic activity, but 2-mercaptoethanol was found to be a potent inhibitor. A polyclonal antibody directed against a synthetic peptide corresponding to the N-terminal amino acid sequence of the chloroplastic CA monomers also recognized the cytosolic CA isoform. This antibody was used for immunocytolocalization experiments which confirmed the intracellular compartmentation of CA: within chloroplasts, CA is restricted to the stroma and appears randomly distributed in the cytosol.

Interleukin-1 beta-specific partial agonists defined by site-directed mutagenesis studies

Monocyte-derived interleukin 1 (IL-1) mediates a wide range of biological effects including destruction of the cartilage matrix in articular diseases such as rheumatoid and osteoarthritis. To elucidate further the relationships between protein structure and biological activities, we have analyzed the sequence of several IL-1 polypeptides using the algorithm of Parker, the hydrophobic cluster analysis method and published structural data. This led us to identify several residues that seemed to be strictly topologically conserved, with respect to identifiable secondary structures features, although this was not readily apparent from sequence alignments. We performed site-directed mutagenesis on some of these conserved residues, as well as on those predicted to occur in external loops of the polypeptide. Human IL-1 beta mutant polypeptides were expressed in Escherichia coli in soluble form and purified to homogeneity by anion-exchange and gel-filtration chromatography. Their biological effects (binding to EL4-6.1 murine thymocytes, Raji human B cells and rabbit chondrocytes cells, lymphocyte activation, neutral protease induction, proteoglycan degradation and synthesis) have been determined. Among the 20 IL-1 beta mutant polypeptides we present here, four showed a markedly reduced activity in cartilage matrix assays without any significant change in their binding to the cartilage matrix cells (chondrocytes). Furthermore, some of these mutants were specific partial agonists of the effects of IL-1 on connective tissue since they have a low affinity for thymocytes.

High-level secretion of correctly processed recombinant human interleukin-1 beta in Kluyveromyces lactis

The lactose-assimilating yeast, Kluyveromyces lactis, has been developed as a microbial host for the synthesis and secretion of human proteins. Here, we report the use of multi-copy vectors based on the 2 mu-like plasmid pKD1 from Kluyveromyces drosophilarum [Chen et al., Nucleic Acids Res. 14 (1986) 4471-4481] for the secretion of recombinant human interleukin-1 beta (reIL-1 beta). High levels of reIL-1 beta were secreted into the growth medium when the structural gene was fused in-frame to a synthetic secretion signal derived from the 'pre'-region of the K. lactis killer toxin. N-terminal sequencing of the excreted protein showed highly efficient (greater than 95%) maturation of the signal sequence. Synthesis as prepro-IL-1 beta, the 'pro'-sequence being derived from the human serum albumin-encoding gene, resulted in equally efficient secretion of mature IL-1 beta. Cytoplasmic production of Met-IL-1 beta, without a secretion signal, was found to be toxic to K. lactis. As in Saccharomyces cerevisiae [Baldari et al., EMBO J. 6 (1987) 229-234], but unlike native human IL-1 beta, K. lactis reIL-1 beta is glycosylated. This glycosylation led to a 95% loss of its biological activity. Removal of the carbohydrate chains by endo-beta-N-acetyl-glucosamidase H treatment fully restored the biological activity. A modified form of IL-1 beta (Asn7----Gln7), in which the unique site for Asn-linked glycosylation was deleted, exhibited the same biological activity as native IL-1 beta. The level of secretion of mature recombinant IL-1 beta ws glycosylation-independent.