Immunological characterization of a rat model of Duchenne’s disease and increase in muscle strength after anti-CD45RC antibody treatment

International audienceIn this study, we phenotyped by flow cytometry and immunohistochemistry (data not shown) the immune cell subsets infiltrating Dmd mdx rat skeletal and cardiac muscles. Leukocyte infiltrates were absent or very low at 2 weeks of age, peaked at 4 and 8 weeks and decreased at 12 weeks. M2 macrophages represented >90% of infiltrating immune cells and Teff cells were the majority of the remaining ones. We also analyzed muscle enzymes and cytokines in sera. Creatin kinase was increased at weeks 4 and 8 and decreased at week 12 and thereafter (data not shown). This results are consistent with those observed in mdx mice model. Anti-CD45RC MAb treatment of young Dmd mdx rats normalized skeletal muscle strength associated to a depletion of effectors CD45RC high cells and no obvious side-effects. As a control prednisolone treatment of Dmd mdx rats similarly increased skeletal muscle strength and was also associated to a depletion of effectors CD45RC high cells but resulted in severe weight loss. Conclusion Duchenne Muscular Dystrophy (DMD) is a severe genetic muscle-wasting disorder due to the lack of dystrophin characterized by a progressive muscle weakness and a cardiomyopathy leading to premature death. The dystrophin-deficient Dmd mdx rats were generated using TALENs and offer a more reliable representation of human DMD, with marked muscle strength reduction, cardiomyopathy and muscle fibrosis that are higher that those observed in the mdx mouse model (1). A role for inflammation and autoimmune responses in muscle damages was shown both in DMD patients and the mdx mouse model (2).In this study, we assessed by flow cytometry and immunohistochemistry the immune cell subsets infiltrating Dmd mdx rat skeletal and cardiac muscles especially immunoregulatory and pro-inflammatory subsets (M1 and M2 macrophages, CD4 + and CD8 + Teff or Tregs…).Then, we investigated the possibility of reducing disease in Dmd mdx rats by administrating immunomodulatory treatments. The standard therapy for DMD patients is corticoids that decrease inflammation and immune responses but with variable responses, limited efficacy and important and numerous side effects. Therefore, there is need for new anti-inflammatory and pro-tolerogenic treatments that could replace or decrease the doses of corticoids. Anti-CD45RC monoclonal antibody (MAb) treatment has induced immune tolerance in models of organ transplantation and GVHD

Breakdown of Immune Tolerance in AIRE-Deficient Rats Induces a Severe Autoimmune Polyendocrinopathy–Candidiasis–Ectodermal Dystrophy–like Autoimmune Disease

International audienceAutoimmune regulator (AIRE) deficiency in humans induces a life-threatening generalized autoimmune disease called autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), and no curative treatments are available. Several models of AIRE-deficient mice have been generated, and although they have been useful in understanding the role of AIRE in central tolerance, they do not reproduce accurately the APECED symptoms, and thus there is still a need for an animal model displaying APECED-like disease. We assessed, in this study, the potential of the rat as an accurate model for APECED. In this study, we demonstrate that in rat, AIRE is expressed by MHC class II (MCH-II)+ and MHC-II- medullary thymic epithelial cells in thymus and by CD4int conventional dendritic cells in periphery. To our knowledge, we generated the first AIRE-deficient rat model using zinc-finger nucleases and demonstrated that they display several of the key symptoms of APECED disease, including alopecia, skin depigmentation, and nail dystrophy, independently of the genetic background. We observed severe autoimmune lesions in a large spectrum of organs, in particular in the pancreas, and identified several autoantibodies in organs and cytokines such as type I IFNs and IL-17 at levels similar to APECED. Finally, we demonstrated a biased Ab response to IgG1, IgM, and IgA isotypes. Altogether, our data demonstrate that AIRE-deficient rat is a relevant APECED animal model, opening new opportunity to test curative therapeutic treatments

CD4+ and CD8+ regulatory T cell characterization in the rat using a unique transgenic Foxp3-EGFP model

Abstract Background Regulatory T cells (Treg) in diverse species include CD4+ and CD8+ T cells. In all species, CD8+ Treg have been only partially characterized and there is no rat model in which CD4+ and CD8+ FOXP3+ Treg are genetically tagged. Results We generated a Foxp3-EGFP rat transgenic line in which FOXP3 gene was expressed and controlled EGFP. CD4+ and CD8+ T cells were the only cells that expressed EGFP, in similar proportion as observed with anti-FOXP3 antibodies and co-labeled in the same cells. CD4+EGFP+ Treg were 5–10 times more frequent than CD8+EGFP+ Treg. The suppressive activity of CD4+ and CD8+ Treg was largely confined to EGFP+ cells. RNAseq analyses showed similarities but also differences among CD4+ and CD8+ EGFP+ cells and provided the first description of the natural FOXP3+CD8+ Treg transcriptome. In vitro culture of CD4+ and CD8+ EGFP− cells with TGFbeta and IL-2 generated induced EGFP+ Treg. CD4+ and CD8+ EGFP+ Treg were expanded upon in vivo administration of a low dose of IL-2. Conclusions This new and unique rat line constitutes a useful model to identify and isolate viable CD4+ and CD8+ FOXP3+ Treg. Additionally, it allows to identify molecules expressed in CD8+ Treg that may allow to better define their phenotype and function not only in rats but also in other species

Immunophenotype of a Rat Model of Duchenne's Disease and Demonstration of Improved Muscle Strength After Anti-CD45RC Antibody Treatment

International audienceCorticosteroids (CS) are standard therapy for the treatment of Duchenne's muscular dystrophy (DMD). Even though they decrease inflammation, they have limited efficacy and are associated with significant side effects. There is therefore the need for new protolerogenic treatments to replace CS. Dystrophin-deficient rats (Dmd mdx ) closely resemble the pathological phenotype of DMD patients. We performed the first Immunophenotyping of Dmd mdx rats and showed leukocyte infiltration in skeletal and cardiac muscles, which consisted mostly of macrophages and T cells including CD45RChigh T cells. Muscles of DMD patients also contain elevated CD45RChigh T cells. We treated Dmd mdx rats with an anti-CD45RC MAb used in previous studies to deplete CD45RChigh T cells and induce immune tolerance in models of organ transplantation. Treatment of young Dmd mdx rats with anti-CD45RC MAb corrected skeletal muscle strength and was associated with depletion of CD45RChigh T cells with no side effects. Treatment of young Dmd mdx rats with prednisolone resulted in increase in skeletal muscle strength but also severe growth retardation. In conclusion, anti-CD45RC MAb treatment has potential in the treatment of DMD and might eventually result in reduction or elimination of CS use

Life Support Limitations in Mechanically Ventilated Stroke Patients

Objectives:. The determinants of decisions to limit life support (withholding or withdrawal) in ventilated stroke patients have been evaluated mainly for patients with intracranial hemorrhages. We aimed to evaluate the frequency of life support limitations in ventilated ischemic and hemorrhagic stroke patients compared with a nonbrain-injured population and to determine factors associated with such decisions. Design:. Multicenter prospective French observational study. Setting:. Fourteen ICUs of the French OutcomeRea network. PATIENTS:. From 2005 to 2016, we included stroke patients and nonbrain-injured patients requiring invasive ventilation within 24 hours of ICU admission. INTERVENTION:. None. MEASUREMENTS AND MAIN RESULTS:. We identified 373 stroke patients (ischemic, n = 167 [45%]; hemorrhagic, n = 206 [55%]) and 5,683 nonbrain-injured patients. Decisions to limit life support were taken in 41% of ischemic stroke cases (vs nonbrain-injured patients, subdistribution hazard ratio, 3.59 [95% CI, 2.78–4.65]) and in 33% of hemorrhagic stroke cases (vs nonbrain-injured patients, subdistribution hazard ratio, 3.9 [95% CI, 2.97–5.11]). Time from ICU admission to the first limitation was longer in ischemic than in hemorrhagic stroke (5 [3–9] vs 2 d [1–6] d; p < 0.01). Limitation of life support preceded ICU death in 70% of ischemic strokes and 45% of hemorrhagic strokes (p < 0.01). Life support limitations in ischemic stroke were increased by a vertebrobasilar location (vs anterior circulation, subdistribution hazard ratio, 1.61 [95% CI, 1.01–2.59]) and a prestroke modified Rankin score greater than 2 (2.38 [1.27–4.55]). In hemorrhagic stroke, an age greater than 70 years (2.29 [1.43–3.69]) and a Glasgow Coma Scale score less than 8 (2.15 [1.08–4.3]) were associated with an increased risk of limitation, whereas a higher nonneurologic admission Sequential Organ Failure Assessment score was associated with a reduced risk (per point, 0.89 [0.82–0.97]). Conclusions:. In ventilated stroke patients, decisions to limit life support are more than three times more frequent than in nonbrain-injured patients, with different timing and associated risk factors between ischemic and hemorrhagic strokes

Association Between Early Invasive Mechanical Ventilation and Day-60 Mortality in Acute Hypoxemic Respiratory Failure Related to Coronavirus Disease-2019 Pneumonia

Objectives:. About 5% of patients with coronavirus disease-2019 are admitted to the ICU for acute hypoxemic respiratory failure. Opinions differ on whether invasive mechanical ventilation should be used as first-line therapy over noninvasive oxygen support. The aim of the study was to assess the effect of early invasive mechanical ventilation in coronavirus disease-2019 with acute hypoxemic respiratory failure on day-60 mortality. Design:. Multicenter prospective French observational study. Setting:. Eleven ICUs of the French OutcomeRea network. Patients:. Coronavirus disease-2019 patients with acute hypoxemic respiratory failure (Pao2/Fio2 ≤ 300 mm Hg), without shock or neurologic failure on ICU admission, and not referred from another ICU or intermediate care unit were included. Intervention:. We compared day-60 mortality in patients who were on invasive mechanical ventilation within the first 2 calendar days of the ICU stay (early invasive mechanical ventilation group) and those who were not (nonearly invasive mechanical ventilation group). We used a Cox proportional-hazard model weighted by inverse probability of early invasive mechanical ventilation to determine the risk of death at day 60. Measurement and Main Results:. The 245 patients included had a median (interquartile range) age of 61 years (52–69 yr), a Simplified Acute Physiology Score II score of 34 mm Hg (26–44 mm Hg), and a Pao2/Fio2 of 121 mm Hg (90–174 mm Hg). The rates of ICU-acquired pneumonia, bacteremia, and the ICU length of stay were significantly higher in the early (n = 117 [48%]) than in the nonearly invasive mechanical ventilation group (n = 128 [52%]), p < 0.01. Day-60 mortality was 42.7% and 21.9% in the early and nonearly invasive mechanical ventilation groups, respectively. The weighted model showed that early invasive mechanical ventilation increased the risk for day-60 mortality (weighted hazard ratio =1.74; 95% CI, 1.07–2.83, p=0.03). Conclusions:. In ICU patients admitted with coronavirus disease-2019-induced acute hypoxemic respiratory failure, early invasive mechanical ventilation was associated with an increased risk of day-60 mortality. This result needs to be confirmed

Non-ventilator-associated ICU-acquired pneumonia (NV-ICU-AP) in patients with acute exacerbation of COPD: From the French OUTCOMEREA cohort

Abstract Background Non-ventilator-associated ICU-acquired pneumonia (NV-ICU-AP), a nosocomial pneumonia that is not related to invasive mechanical ventilation (IMV), has been less studied than ventilator-associated pneumonia, and never in the context of patients in an ICU for severe acute exacerbation of chronic obstructive pulmonary disease (AECOPD), a common cause of ICU admission. This study aimed to determine the factors associated with NV-ICU-AP occurrence and assess the association between NV-ICU-AP and the outcomes of these patients. Methods Data were extracted from the French ICU database, OutcomeRea™. Using survival analyses with competing risk management, we sought the factors associated with the occurrence of NV-ICU-AP. Then we assessed the association between NV-ICU-AP and mortality, intubation rates, and length of stay in the ICU. Results Of the 844 COPD exacerbations managed in ICUs without immediate IMV, NV-ICU-AP occurred in 42 patients (5%) with an incidence density of 10.8 per 1,000 patient-days. In multivariate analysis, prescription of antibiotics at ICU admission (sHR, 0.45 [0.23; 0.86], p = 0.02) and no decrease in consciousness (sHR, 0.35 [0.16; 0.76]; p < 0.01) were associated with a lower risk of NV-ICU-AP. After adjusting for confounders, NV-ICU-AP was associated with increased 28-day mortality (HR = 3.03 [1.36; 6.73]; p < 0.01), an increased risk of intubation (csHR, 5.00 [2.54; 9.85]; p < 0.01) and with a 10-day increase in ICU length of stay (p < 0.01). Conclusion We found that NV-ICU-AP incidence reached 10.8/1000 patient-days and was associated with increased risks of intubation, 28-day mortality, and longer stay for patients admitted with AECOPD

Non-ventilator-associated ICU-acquired pneumonia (NV-ICU-AP) in patients with acute exacerbation of COPD: From the French OUTCOMEREA cohort

Abstract Background Non-ventilator-associated ICU-acquired pneumonia (NV-ICU-AP), a nosocomial pneumonia that is not related to invasive mechanical ventilation (IMV), has been less studied than ventilator-associated pneumonia, and never in the context of patients in an ICU for severe acute exacerbation of chronic obstructive pulmonary disease (AECOPD), a common cause of ICU admission. This study aimed to determine the factors associated with NV-ICU-AP occurrence and assess the association between NV-ICU-AP and the outcomes of these patients. Methods Data were extracted from the French ICU database, OutcomeRea™. Using survival analyses with competing risk management, we sought the factors associated with the occurrence of NV-ICU-AP. Then we assessed the association between NV-ICU-AP and mortality, intubation rates, and length of stay in the ICU. Results Of the 844 COPD exacerbations managed in ICUs without immediate IMV, NV-ICU-AP occurred in 42 patients (5%) with an incidence density of 10.8 per 1,000 patient-days. In multivariate analysis, prescription of antibiotics at ICU admission (sHR, 0.45 [0.23; 0.86], p = 0.02) and no decrease in consciousness (sHR, 0.35 [0.16; 0.76]; p < 0.01) were associated with a lower risk of NV-ICU-AP. After adjusting for confounders, NV-ICU-AP was associated with increased 28-day mortality (HR = 3.03 [1.36; 6.73]; p < 0.01), an increased risk of intubation (csHR, 5.00 [2.54; 9.85]; p < 0.01) and with a 10-day increase in ICU length of stay (p < 0.01). Conclusion We found that NV-ICU-AP incidence reached 10.8/1000 patient-days and was associated with increased risks of intubation, 28-day mortality, and longer stay for patients admitted with AECOPD

Impact of targeted hypothermia in expanded-criteria organ donors on recipient kidney-graft function: study protocol for a multicentre randomised controlled trial (HYPOREME)

International audienceIntroduction: Expanded-criteria donors (ECDs) are used to reduce the shortage of kidneys for transplantation. However, kidneys from ECDs are associated with an increased risk of delayed graft function (DGF), a risk factor for allograft loss and mortality. HYPOREME will be a multicentre randomised controlled trial (RCT) comparing targeted hypothermia to normothermia in ECDs, in a country where the use of machine perfusion for organ storage is the standard of care. We hypothesise that hypothermia will decrease the incidence of DGF.Methods and analysis: HYPOREME is a multicentre RCT comparing the effect on kidney function in recipients of targeted hypothermia (34°C-35°C) and normothermia (36.5°C-37.5°C) in the ECDs. The temperature intervention starts from randomisation and is maintained until aortic clamping in the operating room. We aim to enrol 289 ECDs in order to analyse the kidney function of 516 recipients in the 53 participating centres. The primary outcome is the occurrence of DGF in kidney recipients, defined as a requirement for renal replacement therapy within 7 days after transplantation (not counting a single session for hyperkalemia during the first 24 hours). Secondary outcomes include the proportion of patients with individual organs transplanted in each group; the number of organs transplanted from each ECD and the vital status and kidney function of the recipients 7 days, 28 days, 3 months and 1 year after transplantation. An interim analysis is planned after the enrolment of 258 kidney recipients.Ethics and dissemination: The trial was approved by the ethics committee of the French Intensive Care Society (CE-SRLF-16-07) on 26 April 2016 and by the competent French authorities on 20 April 2016 (Comité de Protection des Personnes-TOURS-Région Centre-Ouest 1, registration #2016-S3). Findings will be published in peer-reviewed journals and presented during national and international scientific meetings