Baseline microbiota composition modulates antibiotic-mediated effects on the gut microbiota and host.

BACKGROUND: Normal mammalian development and homeostasis are dependent upon the gut microbiota. Antibiotics, essential for the treatment and prophylaxis of bacterial infections, can have collateral effects on the gut microbiota composition, which can in turn have far-reaching and potentially deleterious consequences for the host. However, the magnitude and duration of such collateral effects appear to vary between individuals. Furthermore, the degree to which such perturbations affect the host response is currently unclear. We aimed to test the hypothesis that different human microbiomes have different responses to a commonly prescribed antibiotic and that these differences may impact the host response. METHODS: Germ-free mice (n = 30) humanized with the microbiota of two unrelated donors (A and B) were subjected to a 7-day antibiotic challenge with amoxicillin-clavulanate ("co-amoxiclav"). Microbiome and colonic transcriptome analysis was performed, pre (day 0) and post antibiotics (day 8) and subsequently into recovery (days 11 and 18). RESULTS: Unique community profiles were evident depending upon the donor, with donor A recipient mice being dominated by Prevotella and Faecalibacterium and donor B recipient mice dominated by Bacteroides and Parabacteroides. Donor A mice underwent a marked destabilization of their microbiota following antibiotic treatment, while donor B mice maintained a more stable profile. Dramatic and overlapping alterations in the host transcriptome were apparent following antibiotic challenge in both groups. Despite this overlap, donor A mice experienced a more significant alteration in gene expression and uniquely showed correlations between host pathways and key microbial genera. CONCLUSIONS: Germ-free mice humanized by different donor microbiotas maintain distinct microbiome profiles, which respond in distinct ways to antibiotic challenge and evince host responses that parallel microbiome disequilibrium. These results suggest that inter-individual variation in the gut microbiota may contribute to personalized host responses following microbiota perturbation.

Correction to: The expression of HCV-associated host factors is dependent on the hepatoma cell line used in HCV studies.

In this article, a clone of HepG2 stably expressing CD81 (HepG2-CD81) was used. Unfortunately, after cell line authentication.

Alginate hydrogel protects encapsulated hepatic HuH-7 cells against hepatitis C virus and other viral infections.

Cell microencapsulation in alginate hydrogel has shown interesting applications in regenerative medicine and the biomedical field through implantation of encapsulated tissue or for bioartificial organ development. Although alginate solution is known to have low antiviral activity, the same property regarding alginate gel has not yet been studied. The aim of this work is to investigate the potential protective effect of alginate encapsulation against hepatitis C virus (HCV) infection for a hepatic cell line (HuH-7) normally permissive to the virus. Our results showed that alginate hydrogel protects HuH-7 cells against HCV when the supernatant was loaded with HCV. In addition, alginate hydrogel blocked HCV particle release out of the beads when the HuH-7 cells were previously infected and encapsulated. There was evidence of interaction between the molecules of alginate hydrogel and HCV, which was dose- and incubation time-dependent. The protective efficiency of alginate hydrogel towards HCV infection was confirmed against a variety of viruses, whether or not they were enveloped. This promising interaction between an alginate matrix and viruses, whose chemical mechanisms are discussed, is of great interest for further medical therapeutic applications based on tissue engineering.

The expression of HCV-associated host factors is dependent on the hepatoma cell line used in HCV studies.

Chronic infection by hepatitis C virus (HCV) is a major cause of liver cirrhosis and hepatocellular carcinoma. At present, the most commonly used in vitro model of HCV infection is based on hepatoma cell lines. However, they were obtained from different patients and different cancers and/or differ in their characteristics and permissiveness to HCV. HCV infection can be modulated by several host factors, so we compared six different hepatoma cell lines that are used as in vitro models for HCV for some of these host factors: the seven known HCV entry factors, the six best-characterized HCV-associated microRNAs, and the two single-nucleotide polymorphisms near the IL28B gene associated with response to pegylated alpha interferon and ribavirin combination therapy, all assessed by quantitative PCR. We showed that the cell lines, including Huh-7 and Huh-7-derived cells, have different microRNA and HCV entry factor expression profiles as well as different IL28B genotypes. In conclusion, some of the observed differences might explain the differences in permissiveness of the cell lines, but, above all, they raise questions about the reliability of in vitro HCV research data gathered to date.

Detection of erythrovirus B19 in thyroidectomy specimens from Graves' disease patients: a case-control study.

Environmental factors, such as viruses, are thought to contribute to the development of thyroid autoimmunity. Erythrovirus B19 (EVB19) is suspected to be involved in Hashimoto's thyroiditis, but no direct evidence is available concerning the role of EVB19 infection in Graves' disease. The objective of this study was to investigate whether the presence of EVB19 is more frequent in thyroidectomy specimens of patients undergoing thyroidectomy for Graves' disease (cases) than for multinodular thyroid (controls). Serum and thyroidectomy specimens were prospectively collected from 64 patients referred for total thyroidectomy over a 5-year period (2007-2011) and were investigated retrospectively and blindly for circulating EVB19 DNA by q-PCR (Qiagen), and for EVB19 thyrocyte infection by immunochemistry (VP2-Antibody, Dako). EVB19 serology was also determined. General clinical and laboratory data were collected. Twenty patients were referred for Graves' disease and 44 patients were referred for non-autoimmune multinodular thyroid. Patients with thyroid cancer were excluded. Ten percent of Graves' disease patients and 27.7% of control patients had positive staining of thyrocytes for EVB19 antibodies (ns). EVB19-positive and EVB19-negative cases did not differ. EVB19-positive controls were older than EVB19-negative controls (mean age: 57.5 [35-74] vs. 45 [28-80] years, P=0.03) No case of acute EVB19 infection was identified. EVB19-positive serology was more frequent in controls than in Graves' disease patients (88% vs. 45%, P<0.0001). EVB19 was detected in thyrocytes, but not more frequently in Graves' disease patients than in controls. Further studies are needed to determine the role of EVB19 infection in thyroid diseases.

MicroRNAs and hepatitis C virus: toward the end of miR-122 supremacy.

The most common etiologic agents causing chronic hepatitis are hepatitis C and B viruses (HCV and HBV, respectively). Chronic infection caused by HCV is considered one of the major causative agents of liver cirrhosis and hepatocellular carcinoma worldwide. In combination with the increasing rate of new HCV infections, the lack of a current vaccine and/or an effective treatment for this virus continues to be a major public health challenge. The development of new treatments requires a better understanding of the virus and its interaction with the different components of the host cell. MicroRNAs (miRNAs) are small non-coding RNAs functioning as negative regulators of gene expression and represent an interesting lead to study HCV infection and to identify new therapeutic targets. Until now, microRNA-122 (miR-122) and its implication in HCV infection have been the focus of different published studies and reviews. Here we will review recent advances in the relationship between HCV infection and miRNAs, showing that some of them emerge in publications as challengers against the supremacy of miR-122.