No abstract

Background Ulcerative colitis (UC) carries an increased risk of primary and recurrent Clostridiodes difficile infection (rCDI), and CDI is associated with UC flares. We hypothesized that specific fecal microbial changes associate with UC flare and rCDI. Methods We conducted a prospective observational cohort study of 57 patients with UC and CDI, CDI only, and UC only. Stool samples were collected at baseline, at the end of antibiotic therapy, and after reconstitution for 16S rRNA sequencing. The primary outcomes were recurrent UC flare and rCDI. Logistic regression and Lasso models were constructed for analysis. Results There were 21 (45.7%) patients with rCDI, whereas 11 (34.4%) developed UC flare. Patients with rCDI demonstrated significant interindividual (P = 0.008) and intraindividual differences (P = 0.004) in community structure by Jensen-Shannon distance (JSD) compared with non-rCDI. Two cross-validated Lasso regression models predicted risk of rCDI: a baseline model with female gender, hospitalization for UC in the past year, increased Ruminococcaceae and Verrucomicrobia, and decreased Eubacteriaceae, Enterobacteriaceae, Lachnospiraceae, and Veillonellaceae (AuROC, 0.94); and a model 14 days after completion of antibiotics with female gender, increased Shannon diversity, Ruminococcaceae and Enterobacteriaceae, and decreased community richness and Faecalibacterium (AuROC, 0.9). Adding JSD between baseline and post-treatment samples to the latter model improved fit (AuROC, 0.94). A baseline model including UC hospitalization in the past year and increased Bacteroidetes was associated with increased risk for UC flare (AuROC, 0.88). Conclusion Fecal microbial features at baseline and after therapy predict rCDI risk in patients with and without UC. These results may help risk stratify patients to guide management.

Current therapeutic treatments for the repair and/or replacement of damaged skin following disease or traumatic injury is severely limited. The chicken eggshell membrane (ESM) is a unique material: its innate physical and mechanical characteristics offer optimal barrier properties and, as a naturally derived extract, it demonstrates inherent biocompatibility/biodegradability. To further enhance its therapeutic and clinical potential, the ESM can be modified with the thermo-responsive polymer, poly(N-isopropylacrylAmide) (PNIPAAm) as well as the incorporation of (drug-loaded) silver nanoparticles (AgNP); essentially, by a simple change in temperature, the release and delivery of the NP can be targeted and controlled. In this study, ESM samples were isolated using a decellularization protocol, and the physical and mechanical characteristics were profiled using SEM, FT-IR, DSC and DMA. PNIPAAm was successfully grafted to the ESM via amidation reactions and confirmed using FT-IR, which demonstrated the distinctive peaks associated with Amide A (3275 cm−1), Amide B (2970 cm−1), Amide I (1630 cm−1), Amide II (1535 cm−1), CH2, CH3 groups, and Amide III (1250 cm−1) peaks. Confirmation of the incorporation of AgNP onto the stratified membrane was confirmed visually with SEM, qualitatively using FT-IR and also via changes in absorbance at 380 nm using UV-Vis spectrophotometry during a controlled release study for 72 h. The biocompatibility and cytotoxicity of the novel constructs were assessed using human dermal fibroblast (HDFa) and mouse dermal fibroblast (L929) cells and standard cell culture assays. Metabolic activity assessment (i.e., MTS assay), LDH-release profiles and Live/Dead staining demonstrated good attachment and spreading to the samples, and high cell viability following 3 days of culture. Interestingly, longer-term viability (>5 days), the ESM-PNIPAAm and ESM-PNIPAAm (AgNP) samples showed a greater and sustained cell viability profile. In summary, the modified and enhanced ESM constructs were successfully prepared and characterized in terms of their physical and mechanical profiles. AgNP were successfully loaded into the construct and demonstrated a desirable release profile dependent on temperature modulation. Fibroblasts cultured on the extracted ESM samples and ESM-PNIPAAm demonstrated high biocompatibility in terms of high cell attachment, spreading, viability and proliferation rates. As such, this work summarizes the development of an enhanced ESM-based construct which may be exploited as a clinical/therapeutic wound dressing as well as a possible application as a novel biomaterial scaffold for drug development.