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Abstract Background Human multilineage-differentiating stress enduring (Muse) cells are nontumorigenic endogenous pluripotent-like stem cells that can be easily obtained from various adult or fetal tissues. Regenerative effects of Muse cells have been shown in some disease models. Muse cells specifically home in damaged tissues where they exert pleiotropic effects. Exposition of the small intestine to high doses of irradiation (IR) delivered after radiotherapy or nuclear accident results in a lethal gastrointestinal syndrome (GIS) characterized by acute loss of intestinal stem cells, impaired epithelial regeneration and subsequent loss of the mucosal barrier resulting in sepsis and death. To date, there is no effective medical treatment for GIS. Here, we investigate whether Muse cells can prevent lethal GIS and study how they act on intestinal stem cell microenvironment to promote intestinal regeneration. Methods Human Muse cells from Wharton’s jelly matrix of umbilical cord (WJ-Muse) were sorted by flow cytometry using the SSEA-3 marker, characterized and compared to bone-marrow derived Muse cells (BM-Muse). Under gas anesthesia, GIS mice were treated or not through an intravenous retro-orbital injection of 50,000 WJ-Muse, freshly isolated or cryopreserved, shortly after an 18 Gy-abdominal IR. No immunosuppressant was delivered to the mice. Mice were euthanized either 24 h post-IR to assess early small intestine tissue response, or 7 days post-IR to assess any regenerative response. Mouse survival, histological stainings, apoptosis and cell proliferation were studied and measurement of cytokines, recruitment of immune cells and barrier functional assay were performed. Results Injection of WJ-Muse shortly after abdominal IR highly improved mouse survival as a result of a rapid regeneration of intestinal epithelium with the rescue of the impaired epithelial barrier. In small intestine of Muse-treated mice, an early enhanced secretion of IL-6 and MCP-1 cytokines was observed associated with (1) recruitment of monocytes/M2-like macrophages and (2) proliferation of Paneth cells through activation of the IL-6/Stat3 pathway. Conclusion Our findings indicate that a single injection of a small quantity of WJ-Muse may be a new and easy therapeutic strategy for treating lethal GIS.

Abstract Background Accumulating evidence shows a role of the hospital wastewater system in the spread of multidrug-resistant organisms, such as carbapenemase producing Enterobacterales (CPE). Several sequential outbreaks of CPE on the geriatric ward of the Ghent University hospital have led to an outbreak investigation. Focusing on OXA-48 producing Citrobacter freundii, the most prevalent species, we aimed to track clonal relatedness using whole genome sequencing (WGS). By exploring transmission routes we wanted to improve understanding and (re)introduce targeted preventive measures. Methods Environmental screening (toilet water, sink and shower drains) was performed between 2017 and 2021. A retrospective selection was made of 53 Citrobacter freundii screening isolates (30 patients and 23 environmental samples). DNA from frozen bacterial isolates was extracted and prepped for shotgun WGS. Core genome multilocus sequence typing was performed with an in-house developed scheme using 3,004 loci. Results The CPE positivity rate of environmental screening samples was 19.0% (73/385). Highest percentages were found in the shower drain samples (38.2%) and the toilet water samples (25.0%). Sink drain samples showed least CPE positivity (3.3%). The WGS data revealed long-term co-existence of three patient sample derived C. freundii clusters. The biggest cluster (ST22) connects 12 patients and 8 environmental isolates taken between 2018 and 2021 spread across the ward. In an overlapping period, another cluster (ST170) links eight patients and four toilet water isolates connected to the same room. The third C. freundii cluster (ST421) connects two patients hospitalised in the same room but over a period of one and a half year. Additional sampling in 2022 revealed clonal isolates linked to the two largest clusters (ST22, ST170) in the wastewater collection pipes connecting the rooms. Conclusions Our findings suggest long-term circulation and transmission of carbapenemase producing C. freundii clones in hospital sanitary installations despite surveillance, daily cleaning and intermittent disinfection protocols. We propose a role for the wastewater drainage system in the spread within and between rooms and for the sanitary installations in the indirect transmission via bioaerosol plumes. To tackle this problem, a multidisciplinary approach is necessary including careful design and maintenance of the plumbing system.

Abstract In France, all patients followed by Rare Disease (RD) expert centers have to be registered in the National Rare Disease Registry (BNDMR). This database collects a minimum data set including diagnosis coded using the Orphanet nomenclature. Overall, 753,660 patients were recorded from 2007 to March 2022 including 493,740 with at least one rare disease diagnosis. Among these rare disease diagnoses, 1,300 diagnoses gathered between 10 and 70 patients and 792 gathered more than 70 patients, corresponding to more than one patient per million inhabitants. A total of 47 rare disease diagnoses with point prevalence or incidence reported in the literature below 1/1,000,000 have more than 70 patients in the BNDMR, suggesting larger BNDMR cohorts than expected from reported literature. As a conclusion, our national RD registry is a great resource to facilitate patients’ recruitment in clinical research and a better understanding of RD natural history and epidemiology.

Abstract Background Preliminary data suggest that COVID-19 pandemic has generated a switch from face-to-face to remote care for individuals with chronic diseases. However, few data are available for rare and undiagnosed diseases (RUDs). We aimed to assess the impact of the COVID-19 pandemic on the activities of the French reference network for RUDs in 2020. Results In this longitudinal retrospective study, we extracted and analyzed the data of the French national registry for RUDs collected between Jan 1, 2019 and Dec 31, 2020. We compared the annual longitudinal evolution of face-to-face and remote care activities between 2019 and 2020 focusing on adult and pediatric patients. Compared to 2019, rare diseases (RD) care activities showed a decrease in 2020 (− 12%) which occurred mostly during the first lockdown (− 45%) but did not catch up completely. This decrease was mainly in face-to-face care activities. Telehealth activities showed a 9-fold increase during the first lockdown and was able to cover for one third of the decrease in RD activities. Finally, the total number of patients receiving care was lower in 2020(− 9%) with a drastic decrease of cases with newly confirmed diagnosis (− 47%). Conclusion Although telehealth was quickly introduced during the COVID-19 pandemic, RUD patient care was strongly affected in France with a decline in the number of patients treated and new patients recruited. This is likely to result in delays in patient diagnosis and care over the next few years.

Abstract Background Sepsis is a life-threatening organ dysfunction. A fast diagnosis is crucial for patient management. Proteins that are synthesized during the inflammatory response can be used as biomarkers, helping in a rapid clinical assessment or an early diagnosis of infection. The aim of this study was to identify biomarkers of inflammation for the diagnosis and prognosis of infection in patients with suspected sepsis. Methods In total 406 episodes were included in a prospective cohort study. Plasma was collected from all patients with suspected sepsis, for whom blood cultures were drawn, in the emergency department (ED), the department of infectious diseases, or the haemodialysis unit on the first day of a new episode. Samples were analysed using a 92-plex proteomic panel based on a proximity extension assay with oligonucleotide-labelled antibody probe pairs (OLink, Uppsala, Sweden). Supervised and unsupervised differential expression analyses and pathway enrichment analyses were performed to search for inflammatory proteins that were different between patients with viral or bacterial sepsis and between patients with worse or less severe outcome. Results Supervised differential expression analysis revealed 21 proteins that were significantly lower in circulation of patients with viral infections compared to patients with bacterial infections. More strongly, higher expression levels were observed for 38 proteins in patients with high SOFA scores (> 4), and for 21 proteins in patients with worse outcome. These proteins are mostly involved in pathways known to be activated early in the inflammatory response. Unsupervised, hierarchical clustering confirmed that inflammatory response was more strongly related to disease severity than to aetiology. Conclusion Several differentially expressed inflammatory proteins were identified that could be used as biomarkers for sepsis. These proteins are mostly related to disease severity. Within the setting of an emergency department, they could be used for outcome prediction, patient monitoring, and directing diagnostics. Trail registration number: clinicaltrial.gov identifier NCT03841162.

Abstract Background HIV patients face considerable acute and chronic healthcare needs and battling the HIV epidemic remains of the utmost importance. By focusing on health outcomes in relation to the cost of care, value-based healthcare (VBHC) proposes a strategy to optimize quality of care and cost-efficiency. Its implementation may provide an answer to the increasing pressure to optimize spending in healthcare while improving patient outcomes. This paper describes a pragmatic value-based healthcare framework for HIV care. Methods A value-based HIV healthcare framework was developed during a series of roundtable discussions bringing together 16 clinical stakeholder representatives from the Belgian HIV reference centers and 2 VBHC specialists. Each round of discussions was focused on a central question translating a concept or idea to the next level of practical implementation: 1) how can VBHC principles be translated into value-based HIV care drivers; 2) how can these value-based HIV care divers be translated into value-based care objectives and activities; and 3) how can value-based HIV care objectives and activities be translated into value-based care indicators. Value drivers were linked to concrete objectives and activities using a logical framework approach. Finally, specific, measurable, and acceptable structure, process and outcomes indicators were defined to complement the framework. Results Our framework identifies 4 core value areas where HIV care would benefit most from improvements: Prevention, improvement of the cascade of care, providing patient-centered HIV care and sustaining a state-of-the-art HIV disease management context. These 4 core value areas were translated into 12 actionable core value objectives. For each objective, example activities were proposed. Indicators are suggested for each level of the framework (outcome indicators for value areas and objectives, process indicators for suggested activities). Conclusions This framework approach outlines how to define a patient- and public health centered value-based HIV care paradigm. It proposes how to translate core value drivers to practical objectives and activities and suggests defining indicators that can be used to track and improve the framework’s implementation in practice.

Abstract Background For chronic congenital endocrine conditions, age at diagnosis is a key issue with implications for optimal management and psychological concerns. These conditions are associated with an increase in the risk of comorbid conditions, particularly as it concerns growth, pubertal development and fertility potential. Clinical presentation and severity depend on the disorder and the patient’s age, but diagnosis is often late. Objective To evaluate age at diagnosis for the most frequent congenital endocrine diseases affecting growth and/or development. Patients and Methods This observational cohort study included all patients (n = 4379) with well-defined chronic congenital endocrine diseases—non-acquired isolated growth hormone deficiency (IGHD), isolated congenital hypogonadotropic hypogonadism (ICHH), ectopic neurohypophysis (NH), Turner syndrome (TS), McCune-Albright syndrome (MAS), complete androgen insensitivity syndrome (CAIS) and gonadal dysgenesis (GD)—included in the database of a single multisite reference center for rare endocrine growth and developmental disorders, over a period of 14 years. Patients with congenital hypothyroidism and adrenal hyperplasia were excluded as they are generally identified during neonatal screening. Results Median age at diagnosis depended on the disease: first year of life for GD, before the age of five years for ectopic NH and MAS, 8–10 years for IGHD, TS (11% diagnosed antenatally) and CAIS and 17.4 years for ICHH. One third of the patients were diagnosed before the age of five years. Diagnosis occurred in adulthood in 22% of cases for CAIS, 11.6% for TS, 8.8% for GD, 0.8% for ectopic NH, and 0.4% for IGHD. A male predominance (2/3) was observed for IGHD, ectopic NH, ICHH and GD. Conclusion The early recognition of growth/developmental failure during childhood is essential, to reduce time-to-diagnosis and improve outcomes.

Abstract Background In France, the Ministry of Health has implemented a comprehensive program for rare diseases (RD) that includes an epidemiological program as well as the establishment of expert centers for the clinical care of patients with RD. Since 2007, most of these centers have entered the data for patients with developmental disorders into the CEMARA population-based registry, a national online data repository for all rare diseases. Through the CEMARA web portal, descriptive demographic data, clinical data, and the chronology of medical follow-up can be obtained for each center. We address the interest and ongoing challenges of this national data collection system 10 years after its implementation. Methods Since 2007, clinicians and researchers have reported the “minimum dataset (MDS)” for each patient presenting to their expert center. We retrospectively analyzed administrative data, demographic data, care organization and diagnoses. Results Over 10 years, 228,243 RD patients (including healthy carriers and family members for whom experts denied any suspicion of RD) have visited an expert center. Among them, 167,361 were patients affected by a RD (median age 11 years, 54% children, 46% adults, with a balanced sex ratio), and 60,882 were unaffected relatives (median age 37 years). The majority of patients (87%) were seen no more than once a year, and 52% of visits were for a diagnostic procedure. Among the 2,869 recorded rare disorders, 1,907 (66.5%) were recorded in less than 10 patients, 802 (28%) in 10 to 100 patients, 149 (5.2%) in 100 to 1,000 patients, and 11 (0.4%) in > 1,000 patients. Overall, 45.6% of individuals had no diagnosis and 6.7% had an uncertain diagnosis. Children were mainly referred by their pediatrician (46%; n = 55,755 among the 121,136 total children referrals) and adults by a medical specialist (34%; n = 14,053 among the 41,564 total adult referrals). Given the geographical coverage of the centers, the median distance from the patient’s home was 25.1 km (IQR = 6.3 km-64.2 km). Conclusions CEMARA provides unprecedented support for epidemiological, clinical and therapeutic studies in the field of RD. Researchers can benefit from the national scope of CEMARA data, but also focus on specific diseases or patient subgroups. While this endeavor has been a major collective effort among French RD experts to gather large-scale data into a single database, it provides tremendous potential to improve patient care.

Abstract Background Belgium was among the first countries in Europe with confirmed coronavirus disease 2019 (COVID-19) cases. Since the first diagnosis on February 3rd, the epidemic has quickly evolved, with Belgium at the crossroads of Europe, being one of the hardest hit countries. Although risk factors for severe disease in COVID-19 patients have been described in Chinese and United States (US) cohorts, good quality studies reporting on clinical characteristics, risk factors and outcome of European COVID-19 patients are still scarce. Methods This study describes the clinical characteristics, complications and outcomes of 319 hospitalized COVID-19 patients, admitted to a tertiary care center at the start of the pandemic in Belgium, and aims to identify the main risk factors for in-hospital mortality in a European context using univariate and multivariate logistic regression analysis. Results Most patients were male (60%), the median age was 74 (IQR 61–83) and 20% of patients were admitted to the intensive care unit, of whom 63% needed invasive mechanical ventilation. The overall case fatality rate was 25%. The best predictors of in-hospital mortality in multivariate analysis were older age, and renal insufficiency, higher lactate dehydrogenase and thrombocytopenia. Patients admitted early in the epidemic had a higher mortality compared to patients admitted later in the epidemic. In univariate analysis, patients with obesity did have an overall increased risk of death, while overweight on the other hand showed a trend towards lower mortality. Conclusions Most patients hospitalized with COVID-19 during the first weeks of the epidemic in Belgium were admitted with severe disease and the overall case fatality rate was high. The identified risk factors for mortality are not easily amenable at short term, underscoring the lasting need of effective therapeutic and preventative measures.

Abstract Background Children with rare bone diseases (RBDs), whether medically complex or not, raise multiple issues in emergency situations. The healthcare burden of children with RBD in emergency structures remains unknown. The objective of this study was to describe the place of the pediatric emergency department (PED) in the healthcare of children with RBD. Methods We performed a retrospective single-center cohort study at a French university hospital. We included all children under the age of 18 years with RBD who visited the PED in 2017. By cross-checking data from the hospital clinical data warehouse, we were able to trace the healthcare trajectories of the patients. The main outcome of interest was the incidence (IR) of a second healthcare visit (HCV) within 30 days of the index visit to the PED. The secondary outcomes were the IR of planned and unplanned second HCVs and the proportion of patients classified as having chronic medically complex (CMC) disease at the PED visit. Results The 141 visits to the PED were followed by 84 s HCVs, giving an IR of 0.60 [95% CI: 0.48–0.74]. These second HCVs were planned in 60 cases (IR = 0.43 [95% CI: 0.33–0.55]) and unplanned in 24 (IR = 0.17 [95% CI: 0.11–0.25]). Patients with CMC diseases accounted for 59 index visits (42%) and 43 s HCVs (51%). Multivariate analysis including CMC status as an independent variable, with adjustment for age, yielded an incidence rate ratio (IRR) of second HCVs of 1.51 [95% CI: 0.98–2.32]. The IRR of planned second HCVs was 1.20 [95% CI: 0.76–1.90] and that of unplanned second HCVs was 2.81 [95% CI: 1.20–6.58]. Conclusion An index PED visit is often associated with further HCVs in patients with RBD. The IRR of unplanned second HCVs was high, highlighting the major burden of HCVs for patients with chronic and severe disease.

Abstract Background Patient information in rare disease registries is generally collected from numerous data sources, necessitating the data to be federated. In addition, data for research purposes must be de-identified. Transforming nominative data into de-identified data is thus a key issue, while minimizing the number of identity duplicates. We propose a method enabling patient identity federation and rare disease data de-identification while preserving the pertinence of the provided data. Results We developed a rare disease patient identifier. The IdMR generation process is a three-phased algorithm involving a hash function to irreversibly de-identify nominative patient data, including those of foetuses. This process minimizes collision risks and reduces variability for the purpose of identity federation. The IdMR was generated for 360,000 patients of the CEMARA database. It allowed identity federation of 1771 duplicated files. No collisions were introduced. Conclusion We examined and discussed the risks of collisions and the creation of duplicates as well as the risks of patient re-identification. We discussed our choice of nominative input information in light of that used by other patient identification solutions. The IdMR is a patient identifier that enables identity federation and file linkage. The simplicity of the algorithm and the universality and stability of the input data make it a good candidate for European cross-border rare disease projects.

Abstract Background Fibrodysplasia ossificans progressiva (FOP) is a rare, severely disabling, and life-shortening genetic disorder that causes the formation of heterotopic bone within soft connective tissue. Previous studies found that the FOP prevalence was about one in every two million lives. The aim of this study is to estimate the FOP prevalence in France by probabilistic record-linkage of 2 national databases: 1) the PMSI (Programme de médicalisation des systèmes d’information), an administrative database that records all hospitalization activities in France and 2) CEMARA, a registry database developed by the French Centres of Reference for Rare Diseases. Results Using a capture-recapture methodology to adjust the crude number of patients identified in both data sources, 89 FOP patients were identified, which results in a prevalence of 1.36 per million inhabitants (CI95% = [1.10; 1.68]). FOP patients’ mean age was 25 years, only 14.9% were above 40 years, and 53% of them were males. The first symptoms – beside toe malformations- occurred after birth for 97.3% of them. Mean age at identified symptoms was 7 years and above 18 years for only 6.9% of patients. Mean age at diagnosis was 10 years, and above 18 years for 14.9% of the patients. FOP patients were distributed across France. Conclusions Despite the challenge of ascertaining patients with rare diseases, we report a much higher prevalence of FOP in France than in previous studies elsewhere. We suggest that efforts to identify patients and confirm the diagnosis of FOP should be reinforced and extended at both national and European level.

Abstract Background In the last ten years, national rare disease networks have been established in France, including national centres of expertise and regional ones, with storage of patient data in a bioinformatics tool. The aim was to contribute to the development and evaluation of health strategies to improve the management of patients with rare diseases. The objective of this study has been to provide the first national-level data concerning rare diseases of the head, neck and teeth and to assess the balance between demand and supply of care in France. Methods Centres of expertise for rare diseases record a minimum data set on their clinical cases, using a list of rare Head, Neck and Teeth diseases established in 2006. The present analysis focuses on 2008 to 2015 data based on the Orphanet nomenclature. Each rare disease RD “case” was defined by status “affected” and by the degree of diagnostic certainty, encoded as: confirmed, probable or non-classifiable. Analysed parameters, presented with their 95% confidence intervals using a Poisson model, were the following: time and age at diagnosis, proportions of crude and standardized RD prevalence by age, gender and geographical site. The criteria studied were the proportions of patients in Paris Region and the “included cases geography”, in which these proportions were projected onto the other French Regions, adjusting for local populations. Results In Paris Region, estimated prevalence of these diseases was 5.58 per 10,000 inhabitants (95% CI 4.3-7.1). At December 31st 2015, 11,342 patients were referenced in total in France, of whom 7294 were in Paris Region. More than 580 individual clinical entities (ORPHA code) were identified with their respective frequencies. Most abnormalities were diagnosed antenatally. Nearly 80% of patients recorded come to Paris hospitals to obtain either diagnosis, care or follow up. We observed that the rarer the disease, the more patients were referred to Paris hospitals. Conclusions A health network covering a range of aspects of the rare diseases problematic from diagnostics to research has been developed in France. Despite this, there is still a noticeable imbalance between health care supply and demand in this area.

An amendment to this paper has been published and can be accessed via the original article.

Abstract Background Mutation analysis of the neurofibromatosis type 1 (NF1) gene has shown that about 30% of NF1 patients carry a splice mutation resulting in the production of one or several shortened transcripts. Some of these transcripts were also found in fresh lymphocytes of healthy individuals, albeit typically at a very low level. Starting from this initial observation, we were interested to gain further insight into the complex nature of NF1 mRNA processing. Results We have used a RT-PCR plasmid library based method to identify novel NF1 splice variants. Several transcripts were observed with specific insertions/deletions and a survey was made. This large group of variants detected in one single gene allows to perform a comparative analysis of the factors involved in splice regulation. Exons that are prone to skipping were systematically analysed for 5' and 3' splice site strength, branch point strength and secondary structure. Conclusion Our study revealed a complex splicing pattern, generating a great diversity in NF1 transcripts. We found that, on average, exons that are spliced out in part of the mRNA have significantly weaker acceptor sites. Some variants identified in this study could have distinct roles and might expand our knowledge of neurofibromin.