Cytomegalovirus in donors for fecal microbiota transplantation, the phantom menace?

BACKGROUND: Fecal Microbiota Transplantation (FMT) has become the preferred treatment for recurrent Clostridioides difficile Infections (CDI). However, donor screening is a complex process that varies between countries. The primary objective of screening is to prevent the transfer of potential pathogens from the donor to the recipient via feces. Many guidelines recommend Cytomegalovirus (CMV) testing as part of donor screening, but is the risk of CMV transmission well supported by evidence? MATERIALS/METHODS: A French prospective cross-sectional multicenter single-arm study estimated the frequency of detection of CMV in the stool of voluntary healthy donors selected for FMT. All preselected donors were tested for CMV antibodies in blood, and if positive, CMV DNA PCR was performed on whole blood and stool. For samples CMV positive in stool PCR, or case of serological markers positive for IgM, we planned isolation of CMV in cell culture. RESULTS: From June 1, 2016, to July 31, 2017, 500 healthy donors (250 per center) were recruited and 483 included. Of these, 301 were CMV seronegative, and 182 tested positive for CMV IgM and/or IgG. Stool CMV PCR was performed in 162 donors. In two cases, the initial analysis was positive, but below the limit of quantification. Repeated PCR tests using Siemens and Altostar assays were negative. No infectious CMV could be detected in cell culture of these two samples and in the stool of 6 CMV IgM-positive donors. CONCLUSIONS: Our study shows that healthy volunteers with positive CMV serology do not shed CMV DNA in their stool, as detected by PCR or cell culture. This study provides another argument to remove CMV screening for FMT donors.

Follow-up of increased nuchal translucency: Results of a study of 398 cases.

INTRODUCTION: Increased fetal nuchal translucency is associated with chromosomal as well as morphological abnormalities. The psychomotor development of children from these pregnancies is still unclear. The main objective of our study was to evaluate pregnancy outcomes and the post-natal progress of fetuses with increased nuchal translucency. We also compared the features of patients and fetuses according to their nuchal translucency measurement (above 3.5 mm or not). METHODS: Retrospective single-center study in 398 patients in a level 3 maternity unit in France. Mothers whose fetus had a nuchal translucency higher than the 95 th percentile between 2009 and 2018 were included. All patients who had a child with a normal karyotype were prospectively given a questionnaire to evaluate their child's psychomotor development. RESULTS: 37.4% (130/348) of fetuses had a chromosomal abnormality and 2.3% (5/218) had a normal karyotype but a pathogenic copy number variant diagnosed by array- CGH. 28.7% (77/268) of fetus without diagnosed chromosomal abnormalities, presented a morphological abnormality with predominant cardiac malformations. Fetuses with a nuchal translucency ≥ 3.5 mm, had more chromosomal abnormalities (p<0.0001) and were at higher risk of hypotrophy (p=0.005) and birth by cesarean (p=0.04). Among the liveborn children, 70% (166/238) were healthy without morphological or chromosomal abnormalities. Lastly, 17% (17/102) of these children had psychomotor disorder. CONCLUSION: According to our results, parents should be warned of the increased risk of hypotrophy and delivery by cesarean section for fetuses with a nuchal translucency ≥ 3.5 mm. We recommend prolonged specialized pediatric follow-up for children who have been carriers of increased nuchal translucency.

ONCOGRAM: study protocol for the evaluation of therapeutic response and survival of metastatic colorectal cancer patients treated according to the guidelines of a chemosensitivity assay, the Oncogramme®.

BACKGROUND: Colorectal cancer is a major public concern, being the second deadliest cancer in the world. Whereas survival is high for localized forms, metastatic colorectal cancer has showed poor prognosis, with a 5-year survival barely surpassing 11%. Conventional chemotherapies against this disease proved their efficiency and remain essential in first-line treatment. However, the large number of authorized protocols complexifies treatment decision. In common practice, such decision is made on an empirical basis, by assessing benefits and risks for the patient. In other words, there is currently no efficient means of predicting the efficacy of any chemotherapy protocol for metastatic colorectal cancer. METHODS/DESIGN: The use of a chemosensitivity assay, the Oncogramme®, should help clinicians administer the best chemotherapy regimen to their patients. We hypothesize it would ultimately improve their survival. In this multicentred, prospective trial (ONCOGRAM), eligible patients with metastatic colorectal cancer are randomized to determine whether they will receive an Oncogramme®. For clinicians whose patients benefited from the assay (arm A), results are used as a decision support tool. Patients not undergoing the Oncogramme® procedure are treated according to current practice, without the assistance of the assay (arm B). Primary outcome is 1-year progression-free survival. Secondary outcomes include response rates, as well as 6-month and 1-year survival rates. DISCUSSION: This study aims at investigating the clinical utility of the Oncogramme® as a decision support tool for the treatment of patients with metastatic colorectal cancer. If the Oncogramme® positively influenced patient overall survival and/or progression-free survival, it would be of great value for clinicians to implement this assay within the current landscape of personalized medicine tools, which include genomics and biomarker assays. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT03133273 . Registered on April 28, 2017.

Variation in Chst8 gene expression level affects PrPC to PrPSc conversion efficiency in prion-infected Mov cells.

The conversion of the endogenous cellular prion protein to an abnormally folded isoform is a hallmark of transmissible spongiform encephalopathies. It occurs when a misfolded prion protein contacts the cellular PrP. Among the molecular partners suggested to be involved in the misfolding process, the glycosaminoglycans seem to be good candidates. The present study was aimed to examine a possible link between PrP conversion efficiency and transcript level of Chst8 gene that encodes the carbohydrate N-acetylgalactosamine 4-O-sulfotransferase 8. Mov cells expressing ovine PrP were transfected with shRNA directed against Chst8 transcripts. Resulting clones were characterized for their Chst8 and Prnp transcript levels, and for their content in sulfated glycosaminoglycans, more particularly sulfated chondroitins. Unexpectedly, the decreased amount of Chst8 transcript induced an increase of the chondroitin sulfate percentage among total GAGs, with an increased amount of 4-O-sulfation of GalNAc residues. Upon to infection by a sheep prion, a slight amount of PrP(Sc) was observed, which rapidly disappeared upon subpassaging. Together, these findings indicate that the Chst8 transcript level affects the glycosaminoglycan environment of the cellular prion protein, and as a consequence its ability for conversion into PrP(Sc).

Polymorphism of the prion protein in mammals: a phylogenetic approach.

PrP, the principal factor modulating resistance/susceptibility to transmissible spongiform encephalopathies, is a well conserved protein bearing strong phylogenetic information, in spite of its relatively short sequence. The construction of the PrP tree allows inferring the probable ancestral sequence for Bovidae where variants were recorded. This ancestral PrP sequence is constituted by a series of 5 octa-repeats, 3 alpha-helices and 2 beta-strands which combines together to form an antiparallel beta-sheet. The appearance of a 6(th) octa-repeat in the Bovinae ancestor during the evolution of Cetartiodactyla is discussed. Additionally, the variation of the substitution rates of amino acids along the sequence revealed that the sites associated to resistance/susceptibility to TSE are mostly located in conservative regions, including alpha-helices and beta-strands. The composition of most variants very sensitive to TSE in sheep and human corresponds to derived sequences compared to the Eutherian ancestor. However, a homozygous resistant variant in sheep differs from the ancestral state.