Characterization of a new mouse line triggering transient oligodendrocyte progenitor depletion

Oligodendrocyte progenitor cells (OPC) are the main proliferative cells in the healthy adult brain. They produce new myelinating oligodendrocytes to ensure physiological myelin remodeling and regeneration after various pathological insults. Growing evidence suggests that OPC have other functions. Here, we aimed to develop an experimental model that allows the specific ablation of OPC at the adult stage to unravel possible new functions. We generated a transgenic mouse expressing a floxed human diphtheria toxin receptor under the control of the PDGFRa promoter, crossed with an Olig2Cre mouse to limit the recombination to the oligodendrocyte lineage in the central nervous system. We determined a diphtheria toxin dose to substantially decrease OPC density in the cortex and the corpus callosum without triggering side toxicity after a few daily injections. OPC density was normalized 7 days post-treatment, showing high repopulation capacity from few surviving OPC. We took advantage of this strong but transient depletion to show that OPC loss was associated with behavioral impairment, which was restored by OPC recovery, as well as disruption of the excitation/inhibition balance in the sensorimotor cortex, reinforcing the hypothesis of a neuromodulatory role of OPC in the adult brain.

Evaluating H295R steroidogenesis assay data for robust interpretation

The in vitro H295R steroidogenesis assay (OECD TG 456) is used to determine a chemical's potential to interfere with steroid hormone synthesis/metabolism. As positive outcomes in this assay can trigger significant higher tiered testing, we compiled a stakeholder database of reference and test item H295R data to characterize assay outcomes. Information concerning whether a Level 5 reproductive toxicity study was triggered due to a positive outcome in the H295R assay was also included. Quality control acceptance criteria were not always achieved, suggesting this assay is challenging to conduct within the guideline specifications. Analysis of test item data demonstrated that pairwise significance testing to controls allowed for overly sensitive statistically significant positive outcomes, which likely contribute to the assay's high positive hit rate. Complementary interpretation criteria (e.g., 1.5-fold change threshold) markedly reduced the rate of equivocal and positive outcomes thus improving identification of robust positive effects in the assay. Finally, a case study (positive H295R outcome and no endocrine adversity in vivo) is presented, which suggests that stricter data interpretation criteria could refine necessary in vivo follow-up testing. Overall, the described additional criteria could improve H295R data interpretation and help inform on how to best leverage this assay for regulatory purposes.

Controlled donation after circulatory death lung transplantation: Results of the French protocol including in situ abdominal normothermic regional perfusion and ex vivo lung perfusion

BACKGROUND

The French national protocol for controlled donation after circulatory determination of death (cDCD) includes normothermic regional perfusion (NRP) in case of abdominal organ procurement and additional ex-vivo lung perfusion (EVLP) before considering lung transplantation (LT).

METHODS

We made a retrospective study of a prospective registry that included all donors considered for cDCD LT from the beginning of the program in May 2016 to November 2021.

RESULTS

One hundred grafts from 14 donor hospitals were accepted by 6 LT centers. The median duration of the agonal phase was 20 minutes [2-166]. The median duration from circulatory arrest to pulmonary flush was 62 minutes [20-90]. Ten lung grafts were not retrieved due to prolonged agonal phases (n = 3), failure of NRP insertion (n = 5), or poor in situ evaluation (n = 2). The remaining 90 lung grafts were all evaluated on EVLP, with a conversion rate of 84% and a cDCD transplantation rate of 76%. The median total preservation time was 707 minutes [543-1038]. Seventy-one bilateral LTs and 5 single LTs were performed for chronic obstructive pulmonary disease (n = 29), pulmonary fibrosis (n = 21), cystic fibrosis (n = 15), pulmonary hypertension (n = 8), graft-versus-host disease (n = 2), and adenosquamous carcinoma (n = 1). The rate of PGD3 was 9% (n = 5). The 1-year survival rate was 93.4%.

CONCLUSION

After initial acceptance, cDCD lung grafts led to LT in 76% of cases, with outcomes similar to those already reported in the literature. The relative impacts of NRP and EVLP on the outcome following cDCD LT should be assessed prospectively in the context of comparative studies.

Réponse vaccinale contre la Covid en transplantation pulmonaire

Introduction

La vaccination contre la Covid a été recommandée chez les patients transplantés d’organes solides en début d’année 2021, selon un schéma comprenant 3 doses chez les patients n’ayant pas présenté d’infection par la Covid 19 et selon un schéma comprenant 2 injections chez les patients ayant été infectés par la Covid.

Méthodes

Nous avons étudié la réponse vaccinale après un schéma complet dans une cohorte de patients transplantés pulmonaires et cardiopulmonaires à l’hôpital Marie Lannelongue. Selon les recommandations de l’OMS, l’absence de réponse vaccinale est définie par une sérologie dont le taux est < 30 BAU/ml. Le taux d’Anticorps considéré comme protecteur est un taux > 260 BAU/ml. Les patients dont le taux est compris entre 30 et 260 BAU/ml sont considérés comme faiblement répondeurs. La sérologie a été effectuée entre 1 et 3 mois après la dernière injection.

Résultats

Dans notre cohorte comprenant 373 patients, une sérologie Covid a pu être obtenue chez 75% des patients. Une absence complète de séroconversion a été constatée chez 75% des patients. Une séroconversion avec un taux d’anticorps considéré comme protecteur n’a été obtenu que chez 14% des patients, dont la moitié a présenté une infection par la Covid. Par ailleurs, 11% des patients ont été faiblement répondeurs.

Conclusion

Notre étude mono-centrique suggère une très faible réponse vaccinale chez les patients transplantés pulmonaires et cardiopulmonaires, suggérant la réalisation d’une 4^e dose chez les patients partiellement répondeurs et/ou un traitement par anticorps monoclonaux spécifiques chez les patients non répondeurs.

[Radiotherapy for oligometastatic non-small cell lung cancer patients]

The oligometastatic disease concept suggests that patients with a limited number of metastases have a favorable prognosis. Radical local treatment of oligometastatic patients has then increased given developments in imaging (mainly positron emission tomography and brain magnetic resonance imaging) and access to effective and better tolerated treatments. Stereotactic radiotherapy has the advantage of being noninvasive, allowing a good rate of local control and a limited number of side effects. A better definition of oligometastatic disease, particularly for non-small cell lung cancer (NSCLC), has recently been published. For patients with NSCLC, two randomized phase II trials also suggested that the addition of a radical local treatment results in encouraging survival data, with a good safety profile. A single-arm phase II finally showed a benefit when combining a radical local treatment with an anti-PD1 immunotherapy. This review describes the definitions of oligometastatic disease, the main prospective findings including radiation therapy, and prospects for oligometastatic NSCLC patients.

Green reversed-phase HPLC development strategy: Application to artesunate and amodiaquine analysis

A green analytical chemistry strategy is described to develop a reversed-phase high-performance liquid chromatography method for amodiaquine and artesunate analysis using ethanol-based mobile phases. This method development was particularly challenging due to the basicity of amodiaquine and low UV absorption of artesunate, leading to peak asymmetry and detection issues, respectively. UV detection concern was even more challenging due to the baseline drift observed with ethanol in gradient mode. Several green pH modifiers were selected for their ecofriendly character and their impact on peak shape and detection was investigated. The screening of various stationary phases (19 columns) appeared as a relevant and necessary approach to reach satisfactory peak shape of basic compounds. To support the results of this study, some additional compounds related to artesunate and amodiaquine structures were included. Methods were optimized and validated using total error approach with a mobile phase composed of ethanol and 10 mM formic acid using three different stationary phases from different manufacturers, providing flexibility of the quality control approach. Method greenness was assessed using the National Environmental Methods Index, the Green Analytical Procedure Index, and the Analytical Eco-Scale. Finally, artesunate and amodiaquine were successfully analyzed in fixed dose combination tablets.

Radiofrequency ablation versus surgical resection for the treatment of oligometastatic lung disease

PURPOSE

The purpose of this study was to compare efficacy and tolerance between radiofrequency ablation (RFA) and surgery for the treatment of oligometastatic lung disease.

MATERIALS AND METHODS

This retrospective study reviewed patients treated in two institutions for up to 5 pulmonary metastases with a maximal diameter of 4cm and without associated pleural involvement or thoracic lymphadenopathy. Patient demographics, tumor characteristics, treatment outcome, and length of hospital stay were compared between the two groups. Efficacy endpoints were overall survival (OS), progression-free survival (PFS) and pulmonary or local tumor progression rates.

RESULTS

Among 204 patients identified, 78 patients (42 men, 36 women; mean age, 53.3±14.9 [SD]; age range: 15-81 years) were treated surgically, while 126 patients (59 men, 67 women; mean age, 62.2±10.8 [SD]; age range: 33-80 years) were treated by RFA. In the RFA cohort, patients were significantly older (P<0.0001), with more extra-thoracic localisation (P=0.015) and bilateral tumour burden (P=0.0014). In comparison between surgery and RFA cohorts, respectively, the 1- and 3-year OS were 94.8 and 67.2% vs. 94 and 72.1% (P=0.46), the 1- and 3-year PFS were 49.4% and 26.1% vs. 38.9% and 14.8% (P=0.12), the pulmonary progression rates were 39.1% and 56% vs. 41.2% and 65.3% (P>0.99), and the local tumour progression rates were 5.4% and 10.6% vs. 4.8% and 18.6% (P=0.07). Tumour size>2cm was associated with a significantly higher local tumor progression in the RFA group (P=0.010). Hospitalisation stay was significantly shorter in the RFA group (median of 3 days; IQR=2 days; range: 2-12 days) than in the surgery group (median of 9 days; IQR=2 days; range: 6-21 days) (P<0.01).

CONCLUSION

RFA should be considered a minimally-invasive alternative with similar OS and PFS to surgery in the treatment of solitary or multiple lung metastases measuring less than 4cm in diameter without associated pleural involvement or thoracic lymphadenopathy.

[Role of immunotherapy in locally advanced non-small cell lung cancer]

Concomitant radiochemotherapy has been the standard of care for unresectable stage III non-small cell lung cancer (NSCLC), irrespective of histological sub-type or molecular characteristics. Currently, only 15-30 % of patients are alive five years after radiochemotherapy, and this figure remains largely unchanged despite multiple phase III randomised trials. In recent years, immune-checkpoint blockades with anti-PD-(L)1 have revolutionised the care of metastatic NSCLC, becoming the standard front- and second-line strategy. Several preclinical studies reported an increased tumour antigen release, improved antigen presentation, and T-cell infiltration in irradiated tumours. Immunotherapy has therefore recently been evaluated for patients with locally advanced stage III NSCLC. Following the PACIFIC trial, the anti-PD-L1 durvalumab antibody has emerged as a new standard consolidative treatment for patients with unresectable stage III NSCLC whose disease has not progressed following concomitant platinum-based chemoradiotherapy. Immunoradiotherapy therefore appears to be a promising association in patients with localised NSCLC. Many trials are currently evaluating the value of concomitant immunotherapy and chemoradiotherapy and/or consolidative chemotherapy with immunotherapy in patients with locally advanced unresectable NSCLC.

Blood CD9+ B cell, a biomarker of bronchiolitis obliterans syndrome after lung transplantation

Bronchiolitis obliterans syndrome is the main limitation for long-term survival after lung transplantation. Some specific B cell populations are associated with long-term graft acceptance. We aimed to monitor the B cell profile during early development of bronchiolitis obliterans syndrome after lung transplantation. The B cell longitudinal profile was analyzed in peripheral blood mononuclear cells from patients with bronchiolitis obliterans syndrome and patients who remained stable over 3 years of follow-up. CD24^hi CD38^hi transitional B cells were increased in stable patients only, and reached a peak 24 months after transplantation, whereas they remained unchanged in patients who developed a bronchiolitis obliterans syndrome. These CD24^hi CD38^hi transitional B cells specifically secrete IL-10 and express CD9. Thus, patients with a total CD9⁺ B cell frequency below 6.6% displayed significantly higher incidence of bronchiolitis obliterans syndrome (AUC = 0.836, PPV = 0.75, NPV = 1). These data are the first to associate IL-10-secreting CD24^hi CD38^hi transitional B cells expressing CD9 with better allograft outcome in lung transplant recipients. CD9-expressing B cells appear as a contributor to a favorable environment essential for the maintenance of long-term stable graft function and as a new predictive biomarker of bronchiolitis obliterans syndrome-free survival.

[Massive pulmonary embolism. When medical treatment is not enough]

Emergency bedside veno-arterious ECMO implantation can be the only saving gesture in the suspicion of acute massive pulmonary embolism leading to haemodynamic failure, even before CT-scan imaging. Once the massive pulmonary embolism is confirmed it is possible to undergo surgical or percutaneous pulmonary thrombectomy, when thrombolytic therapy is contraindicated.

Mesoporous Silica Nanoparticles under Sintering Conditions: A Quantitative Study

Thin films made of mesoporous silica nanoparticles (MSNs) are finding new applications in catalysis, optics, as well as in biomedicine. The fabrication of MSNs thin films requires a precise control over the deposition and sintering of MSNs on flat substrates. In this study, MSNs of narrow size distribution (150 nm) are synthesized, and then assembled onto flat silicon substrates, by means of a dip-coating process. Using concentrated MSN colloidal solutions (19.5 mg mL(-1) SiO2), withdrawal speed of 0.01 mm s(-1), and well-controlled atmospheric conditions (ambient temperature, ∼ 70% of relative humidity), monolayers are assembled under well-structured compact patterns. The thin films are sintered up to 900 °C, and the evolution of the MSNs size distributions are compared to those of their pore volumes and densities. Particle size distributions of the sintered thin films were precisely fitted using a model specifically developed for asymmetric particle size distributions. With increasing temperature, there is first evidence of intraparticle reorganization/relaxation followed by intraparticle sintering followed by interparticle sintering. This study is the first to quantify the impact of sintering on MSNs assembled as thin films.

Inactivation of p53 Is Sufficient to Induce Development of Pulmonary Hypertension in Rats

Objective

Pulmonary artery smooth muscle cells (PA-SMCs) in pulmonary arterial hypertension (PAH) show similarities to cancer cells. Due to the growth-suppressive and pro-apoptotic effects of p53 and its inactivation in cancer, we hypothesized that the p53 pathway could be altered in PAH. We therefore explored the involvement of p53 in the monocrotaline (MCT) rat model of pulmonary hypertension (PH) and the pathophysiological consequences of p53 inactivation in response to animal treatment with pifithrin-α (PFT, an inhibitor of p53 activity).

Methods and Results

PH development was assessed by pulmonary arterial pressure, right ventricular hypertrophy and arterial wall thickness. The effect of MCT and PFT on lung p53 pathway expression was evaluated by western blot. Fourteen days of daily PFT treatment (2.2 mg/kg/day), similar to a single injection of MCT (60 mg/kg), induced PH and aggravated MCT-induced PH. In the first week after MCT administration and prior to PH development, p53, p21 and MDM2 protein levels were significantly reduced; whereas PFT administration effectively altered the protein level of p53 targets. Anti-apoptotic and pro-proliferative effects of PFT were revealed by TUNEL and MTT assays on cultured human PA-SMCs treated with 50 μM PFT.

Conclusions

Pharmacological inactivation of p53 is sufficient to induce PH with a chronic treatment by PFT, an effect related to its anti-apoptotic and pro-proliferative properties. The p53 pathway was down-regulated during the first week in the rat MCT model. These in vivo experiments implicate the p53 pathway at the initiation stages of PH pathogenesis.