Vitamin D3 inhibits p38 MAPK and senescence-associated inflammatory mediator secretion by senescent fibroblasts that impacts immune responses during ageing

Vitamin D3 replacement in older insufficient adults significantly improves their antigen-specific varicella zoster virus (VZV) cutaneous immunity. However, the mechanisms involved in this enhancement of cutaneous immunity are not known. Here, we show for the first time that vitamin D3 blocks the senescence-associated secretory phenotype (SASP) production by senescent fibroblasts by partially inhibiting the p38 MAPK pathway. Furthermore, transcriptomic analysis of skin biopsies from older subjects after vitamin D3 supplementation shows that vitamin D3 inhibits the same inflammatory pathways in response to saline as the specific p38 inhibitor, losmapimod, which also enhances immunity in the skin of older subjects. Vitamin D3 supplementation therefore may enhance immunity during ageing in part by blocking p38 MAPK signalling and in turn inhibit SASP production from senescent cells in vivo.

Infection nosocomiale et clusters intra hospitalier d'infection à SARS cov 2 dans un centre hospitalier Général : Bilan d'une année de pandémie

Introduction

La mise à disposition large des tests PCR SARS cov2 et la stratégie de dépistage systématique autour d'un cas a permis de mettre en évidence la survenue de transmissions croisées entrainant des infections nosocomiales au sein des services de soins. Un cluster est défini par la présence d'au moins 3 cas dans un service de soins dans un délai de 14 jours. L'objectif de l'étude est de définir le nombre de cas d'infection nosocomiale et de phénomène de cluster hospitalier aux décours de la 2ème et 3ème vague d'infection à SARS cov 2 dans un centre hospitalier Général.

Matériels et méthodes

Etude rétrospective des infections nosocomiales et des clusters intra hospitalier entre avril 2020 et avril 2021 L'infection nosocomiale est définie par la négativité d'une PCR d'entrée et la positivité d'une PCR à plus de 7 jours de l'entrée. Un cluster est défini par au moins trois cas d'infection nosocomiale dans une même unité de lieux et de temps (14jours). La deuxième vague comprend les cas identifiés entre les mois d'octobre et décembre 2020 et janvier avril 2021 pour la troisième.

Résultats

Quatre mille deux cents cinq PCR positives ont été détectées entre avril 2020 et avril 2021. Le nombre covid nosocomiaux était de 123 des 1654 patients hospitalisés (7.4 %) et ayant un diagnostic virologique d'infection à SARScov2. Cent onze (79 %) des cas nosocomiaux étaient liés à des clusters. Durant la deuxième vague, 14 clusters ont été détectés dans 8 services différents (moyenne de 5 patients par épisodes avec au minimum 3 et au maximum 18 patients par cluster). Pendant la troisième vague, 4 clusters ont été identifiés dans 4 services. La durée moyenne de résolution des clusters a été de 14 jours. Les clusters ont été détectés pour 58 cas (47 %)en secteur médecine chirurgie obstétrique et pour 65 (53 %) cas en secteur soins de suite et rééducation.

La moyenne d'âge des cas nosocomiaux était de 83 ans, 85,37 % présentaient au moins une comorbidité et la mortalité a été de 22,76 % contre 19 % pour les cas communautaire (Xhi² = 1.03 NS).

Conclusion

L'acquisition nosocomiale du virus SARS cov 2 a été est un phénomène bien réel entrainant une surmortalité en milieu hospitalier. Ces données patients permettent de justifier les mesures spécifiques comme la vaccination précoce et obligatoire des personnels soignants et des patients à risque, un renforcement des mesures d'hygiène et un contrôle des visites.

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Facteurs associés au portage de BMR à l'entrée en réanimation des patients infectés par la COVID-19 : analyse de cohorte rétrospective

Introduction

Une étude précédente réalisée dans notre hôpital, montrait un taux de portage de bactéries multirésistantes (BMR) à l'entrée en réanimation, chez les patients développant une pneumopathie acquise sous ventilation, différent chez les patients infetés par la COVID-19 par rapport aux non infectés (30 % VS 16 %, p=0,043). Nous avons analysé les facteurs de risque (FDR) d'un tel portage et son impact sur la survie des patients.

Matériels et méthodes

Analyse rétrospective, monocentrique, des patients hospitalisés en service de réanimation ou de soins continus pour une infection à COVID-10 pendant les vagues 1 (01/03/20 au 01/05/20) et 2 (15/10/21) ayant bénéfié d'un dépistage systématique de BMR à leur entrée dans le service.

Résultats

141 patients (98 homes et 43 femmes) ont été inclus dans l'étude, 68 durant la première vague et 73 durant la seconde. 24 des 141 patients (17 %) étaient porteurs de BMR à l'entrée en réanimation. Nous n'observons pas de différence significative du taux de portage entre les deux vagues (13/68 (19 %) et 11/73 (15 %) patients respectivement p=0,65).

Les facteurs associés au portage de BMR sont le passage dans une strucutre d'hospitalisation autre que notre hôpital (p=0,02) en particulier chez les patients venant d'une autre réanimation (5/13, 38,5 %), d'un service d'urgences (2/6, 33 %) ou d'une unité conventionnelle (6/24, 25 %) par rapport à ceux directement hospitalisés dans la réanimation de notre hôpital (11/98, 11,2 %).

L'autre FDR de portage de BMR est l'exposition à une antibiothérapie au cours de la période d'hospitalisation ayant précédée la réanimation ou les soins continus, notamment aux Bêta-lactamines (13/49 vs 11/92, p=0,035) et aux macrolides (10/30 vs 14/111, p=0,01).

Nous n'avons pas retrouvé d'association significative avec les FDR usuels tels que : vie en institution, présence d'une néoplasie en cours de traitement, traitement immunosuppresseur ou BPCO. Il n'y a pas non plus de différence liée à la consommation d'antibiotiques en ambulatoire dans les 15 jours précédents l'hospitalisation (3/24 (13 %) vs 21/118 (17 %) p=0,76) ou la durée d'hospitalisation avant le transfert en réanimation (2.1 vs 2.3 jours p=0,86).

Dans notre étude, le portage de BMR à l'entrée en réanimation est associée à un sur-risque de mortalité avec un taux de survie de 41,7 % (10/24) chez les patients porteurs de BMR contre 67,2 % (79/117) chez les patients non porteurs de BMR (p=0,02).

Conclusion

Le portage de BMR à l'entréer en réanimation ou soins continus chez les patients infectés par la COVID-19 dans notre hôpital est significativement associé au transfert depuis un autre hôpital et à la prise d'antibiotiques en hospitalisation conventionnelle avant l'admission en service réanimatoire, notamment la prise de Bêta-lactamines et/ou de macrolides. Ce portage est associée à une mortalité plus élevée.

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Evidence for tmTNF reverse signaling in vivo: Implications for an arginase-1-mediated therapeutic effect of TNF inhibitors during inflammation

In order to ascertain the significance of transmembrane tumor necrosis factor (tmTNF) reverse signaling in vivo, we generated a triple transgenic mouse model (3TG, TNFR1−/−, TNFR2−/−, and tmTNFKI/KI) in which all canonical tumor necrosis factor (TNF) signaling was abolished. In bone-marrow-derived macrophages harvested from these mice, various anti-TNF biologics induced the expression of genes characteristic of alternative macrophages and also inhibited the expression of pro-inflammatory cytokines mainly through the upregulation of arginase-1. Injections of TNF inhibitors during arthritis increased pro-resolutive markers in bone marrow precursors and joint cells leading to a decrease in arthritis score. These results demonstrate that the binding of anti-TNF biologics to tmTNF results in decreased arthritis severity. Collectively, our data provide evidence for the significance of tmTNF reverse signaling in the modulation of arthritis. They suggest a complementary interpretation of anti-TNF biologics effects in the treatment of inflammatory diseases and pave the way to studies focused on new arginase-1-dependent therapeutic targets.

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In vivo demonstration of tmTNF reverses signaling existence

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tmTNF reverse signaling induces anti-oxidative stress response

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tmTNF reverse signaling induces an arginase-1-mediated anti-inflammatory response

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Reverse signaling is a complementary mechanism to TNF neutralization by anti-TNF

Does a 5-day course of antibiotics in elderly patients with community-acquired pneumonia achieve the established criteria of clinical stability?

OBJECTIVE

We aimed to determine the proportion of elderly patients hospitalised for community-acquired pneumonia (CAP) in whom a 5-day antibiotic therapy would achieve clinical stability according to American Thoracic Society (ATS) criteria.

METHODS

Patients aged≥75 years, hospitalised for CAP between November 2018 and August 2019, were analysed retrospectively. The American Thoracic Society (ATS) clinical stability criteria (temperature≤37°C, heart rate≤100/min, respiratory rate≤24/min, systolic blood pressure≥90mmHg, oxygen saturation≥90% in room air) were assessed after five days of antibiotic therapy.

RESULTS

Seventy-five patients (mean age 88 years, 49% requiring oxygen therapy) were included. Six died, and at day 5, 36/69 (52%) fulfilled 4/5 stability criteria. The median duration of treatment was 9 days. In 28 patients (41%), it was ≤7 days.

CONCLUSION

In 52% of elderly patients with CAP, a 5-day treatment regimen resulted in clinical stability.

Inhibition of Osteoclastogenesis by the RNA-Binding Protein QKI5: a Novel Approach to Protect from Bone Resorption

Increased osteoclastogenesis is a common feature of bone erosion, notably in osteoporosis but also in inflammatory diseases such as rheumatoid arthritis (RA) and osteoarticular infections. Human cytomegalovirus (HCMV) infection has been described to impair monocyte differentiation into macrophages and dendritic cells. However, its effect on monocyte-derived osteoclasts is yet to be determined. We showed here that in vitro HCMV infection is associated with an inhibition of osteoclastogenesis through decreased expression of colony stimulating factor 1 receptor (CSF-1R) and RANK in monocytes, which was mediated by an upregulation of quaking I-5 protein (QKI-5), a cellular RNA-interacting protein. We found that deliberate QKI5 overexpression in the absence of HCMV infection is able to decrease CSF-1R and RANK expression, leading to osteoclastogenesis inhibition. Finally, by using lentiviral vectors in a calvarial bone erosion mouse model, we showed that QKI5 inhibits bone degradation. This work identifies QKI5 as a strong inhibitor of bone resorption. Future research will point out whether QKI5 could be a target for bone pathologies. © 2019 American Society for Bone and Mineral Research.

Rheumatoid Synovial Fluids Regulate the Immunomodulatory Potential of Adipose-Derived Mesenchymal Stem Cells Through a TNF/NF-κB-Dependent Mechanism

Introduction: Adipose-derived mesenchymal stem cells (ADSC) have been shown to have remarkable immune-modulating effects. However, their efficacy in clinical trials has yet to be fully demonstrated. This could be due to a lack of a proper inflammatory environment in vivo that primes ADSC. Here, we define how the articular microenvironment of rheumatoid arthritis (RA) patients modulates the therapeutic efficiency of ADSC. Methods: Synovial fluids (SF) were collected from 8 RA patients, 2 Spondyloarthritis patients and one control synovial fluid from a patient undergoing traumatic-related surgery. SF inflammatory status was determined by routine analysis and quantification of pro-inflammatory cytokines. ADSC were first treated with SF and ADSC proliferation and gene expression of immunomodulatory factors was evaluated. In order to determine the mechanisms underlying the effect of SF on ADSC, tumor necrosis factor (TNF), interleukin-6 (IL-6), and NF-κB neutralization assays were performed. To evaluate the effect of SF on ADSC functions, ADSC were pre-treated with SF and then co-cultured with either macrophages or T cells. The modulation of their phenotype was assessed by flow cytometry. Results: Pro-inflammatory RASF maintained the proliferative capacity of ADSC and upregulated the gene expression of cyclooxygenase-2 (COX2), indoleamine-1,2-dioxygenase (IDO), interleukin-6 (IL-6), tumor-necrosis factor stimulated gene 6 (TSG6), intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and programmed death-ligand 1 (PD-L1), all factors involved in ADSC immunomodulatory potential. The RASF-induced gene expression was mainly mediated by TNF alone or in combination with IL-6 and signaled through the NF-κB pathway. Conditioning ADSC with pro-inflammatory RASF enhanced their ability to induce CD4⁺Foxp3⁺CD25^high regulatory T cells (Tregs) and inhibit pro-inflammatory markers CD40 and CD80 in activated macrophages. Conclusions: Inflammatory synovial fluids from RA patients had the capacity to modulate ADSC response, to induce Tregs and modulate the phenotype of macrophages. The clinical use of ADSC in affected joints should take into account the influence of the local articular environment on their potential. Having a sufficient pro-inflammatory microenvironment will determine whether optimal immunoregulatory response should be expected. Direct ADSC intra-articular delivery to patients could be a potential strategy to properly prime their immunomodulatory potential and enhance their clinical benefits.

Prevalence of physical activity and sedentary-related behaviors among adolescents: data from the Qatar National School Survey

OBJECTIVES

To investigate the prevalence of physical activity (PA) and sedentary behaviors among adolescents in Qatar by selected demographic characteristics.

STUDY DESIGN

Cross-sectional study.

METHODS

A total of 5862 students (2938 boys and 2924 girls) in the age group 12-17 years were included in the analyses. PA and sedentary-related measures were obtained from the self-reported survey questions.

RESULTS

Only 35.4% of students were performing 60 min of PA ≥3 days/week. The proportion of students with >2 hr screentime ranged from 43% to 57% (weekdays) and 50% to 62.5% (weekends). Girls had less odds of being physically active than the boys (odds ratio [OR] = 0.61, P < 0.001). Qatari students were less likely to be physically active than non-Qataris (OR = 0.79, P < 0.001). Age was inversely correlated with PA ([r = -0.113, P < 0.001 for participation with sports team] and [r = -0.139, P < 0.001 for school physical education classes]). Participation in sports teams positively correlated with 60 min of PA number of days in a week (r = 0.317, P < 0.001).

CONCLUSIONS

The study describes insufficient PA among youth as a public health issue of concern in the State of Qatar that requires multipronged health promotion initiatives.

Comparative effect of 25(OH)D3 and 1,25(OH)2D3 on Th17 cell differentiation

Vitamin D is a secosteroid hormone that plays an important regulatory role in calcium homeostasis and bone metabolism. Immune cells can both produce and respond to 1,25(OH)2D3. CD4+ T cells from vitamin D receptor (VDR) KO mice produce higher levels of IFN-γ and IL-17 than their wild type counterparts, and play a crucial role in the pathogenesis of autoimmune diseases (AID). We are particularly interested in studying the effect of vitamin D on pathogenic Th17 cells in humans. We investigated the in vitro effect of 1,25(OH)2D3 and 25(OH)D3 on the differentiation and cytokine production of primary CD4+ T cells from normal donors, and cultured in Th17 polarizing conditions. Both forms of vitamin D reduced the expression of pathogenic Th17 markers and their secretion of pro-inflammatory cytokines (IL-17A, IFN-γ). Furthermore, both vitamin D forms induced an expansion of CD25hi cells and upregulated their expression of CTLA-4 and Foxp3 regulatory markers.

Effect of 1,25(OH)2D3 on in vitro differentiation of human naïve and CD4+ T cells to Th17 and Treg subsets (IRC5P.630)

The balance between Th17 and Tregs influences the pathogenesis of autoimmune diseases. The active form of vitamin D, 1α,25-dihydroxyvitamin D3, was shown to exert anti-inflammatory effect. The aim of this study is to investigate the effect of vitamin D on the differentiation of naïve and total CD4+ T cells into pathogenic Th17 subset and regulatory T cells ex-vivo in healthy controls, and to characterize their phenotype and its modulation by vitamin D. Purified naïve and total CD4+ T cells were activated in Th17 and Treg polarizing conditions in the presence or absence of 1,25(OH)2D3 for 6 days. Cells were processed for multiparameter staining and flow cytometry, and cell culture supernatants were reserved for cytokine quantitation by cytometric bead array for IL-17A, IL-10, IL-6, TNF-α, IL-2, IFN-γ, and IL-4. In Th17 cell cultures, overall expression of CCR6 and the percentage of CCR6+IL-17A+CD4+ T cells is decreased with Vitamin D. Interestingly, IL-23R and IL-23R+IL-17A+ cells, as well as IL-17+IFN-γ+ cells associated with pathogenic Th17 cells are reduced, while Foxp3+ cells are increased. In the presence of vitamin D, Treg polarized CD4+ T cells upregulated CD25 and CTLA4 expression but not Foxp3. Foxp3 expression was reduced in both CD25hi and CD25lo cells. Cytokine analysis by CBA and Treg suppression assays are underway. Results obtained thus far point to an effect for Vitamin D in reducing pathogenic Th17 cells, and modulating the induction of regulatory T cells.

A cluster of pediatric metallic mercury exposure cases treated with meso-2,3-dimercaptosuccinic acid (DMSA)

Nine children and their mother were exposed to vapors of metallic mercury. The source of the exposure appears to have been a 6-oz vial of mercury taken from a neighbor's home. The neighbor reportedly operated a business preparing mercury-filled amulets for practitioners of the Afro-Caribbean religion Santeria. At diagnosis, urinary mercury levels in the children ranged from 61 to 1,213 microg/g creatinine, with a geometric mean of 214.3 microg/m creatinine. All of the children were asymptomatic. To prevent development of neurotoxicity, we treated the children with oral meso-2,3-dimercaptosuccinic acid (DMSA). During chelation, the geometric mean urine level rose initially by 268% to 573.2 microg mercury/g creatinine (p<0.0005). At the 6-week follow-up examination after treatment, the geometric mean urine mercury level had fallen to 102.1 microg/g creatinine, which was 17.8% of the geometric mean level observed during treatment (p<0.0005) and 47.6% of the original baseline level (p<0.001). Thus, oral chelation with DMSA produced a significant mercury diuresis in these children. We observed no adverse side effects of treatment. DMSA appears to be an effective and safe chelating agent for treatment of pediatric overexposure to metallic mercury.

An in vivo model of femtosecond laser intrastromal refractive surgery

BACKGROUND AND OBJECTIVE

To develop an animal model for evaluation of femtosecond laser intrastromal refractive surgery.

METHODS

Intrastromal photodisruption was performed in New Zealand Albino rabbits using a femtosecond laser system. This surgical pattern consisted of a 100 microm-tick pyramid of laser pulses starting 180 microm below the corneal surface. Animals underwent serial slit lamp examinations and corneal thickness measurements at 1,3,7,14, and 28 days, then monthly up to 1 year.

RESULTS

Approximately 70 microm of central corneal thinning were seen at 1 week, remaining stable up to 7 months.

CONCLUSIONS

Intrastromal photodisruption with femtosecond lasers produced consistent changes in corneal thickness without loss of corneal transparency. These changes were more stable than those produced with excimer laser procedures in a similar animal model.

[Simultaneous traumatic dislocations of the index finger. Apropos of a case with review of the literature]

A new case of simultaneous dislocation of the proximal and distal interphalangeal joints on the same digit is reported. This injury is uncommon in the index. The forces were applied to the finger tip in hyperextension position. Closed treatment provided a good result with full range of motion. Therapeutic options are discussed.

Hyperactivation of the silencing proteins, Sir2p and Sir3p, causes chromosome loss

The SIRgene products maintain transcriptional repression at the silent mating type loci and telomeres in Saccharomyces cerevisiae, although no enzymatic or structural activity has been assigned to any of the Sir proteins nor has the role of any of these proteins in transcriptional silencing been clearly defined. We have investigated the functions and interactions of the Sir2, Sir3, and Sir4 proteins by overexpressing them in yeast cells. We find that Sir2p and Sir3p are toxic when overexpressed, while high Sir4p levels have no toxic effect. Epistasis experiments indicate that Sir2p-induced toxicity is diminished in strains lacking the SIR3 gene, while both Sir2p and Sir4p are required for Sir3p to manifest its full toxic effect. In addition, the effects of Sir2 or Sir3 overexpression are exacerbated by specific mutations in the N-terminus of the histone H4 gene. These results are consistent with a model in which Sir2p, Sir3p and Sir4p function as a complex and interact with histones to modify chromatin structure. We find no evidence that toxicity from high levels of the Sir proteins results from widespread repression of transcription. Instead, we find that high levels of Sir2p and/or Sir3p cause a profound decrease in chromosome stability. These results can be appreciated in the context of the effects of Sir2p in histone acetylation and of chromatin structure on chromosome stability.

[Transverse fracture of the body of C2. Apropos of a case]

INTRODUCTION

A new fracture of the body of C2 is described. The mechanism is an axial compression producing a body sagittal fracture spreading to the posterior arch with a separation effect.

CASE REPORT

A 29 years old female fell from the second floor. Examination showed a head injury and upper neck stiffness. Specific radiological signs was reported on the standard X-ray. The fracture involved the body and the lamina of C2 with a sagittal separation. No neurological abnormality was detected. CT scan provided additional information and allowed the survey of bone healing. Non operative treatment was undertaken by minerva jacket for four months carying complete recovery.

DISCUSSION

The mechanism of this fracture seems to be similar to Jefferson's fracture. Review of the literature showed that fractures of the body of C2 are uncommon. Their different types are discussed.