The host immune response affects pathogen virulence in Clostridium difficile infection (CDI). Thus, cytokine responses to CDI likely are associated with disease initiation and progression. Understanding the molecular drivers of inflammation and biochemical markers of disease severity is important for developing novel therapies and predicting disease prognosis. In this study, we investigated cytokine production in patients with CDI and evaluated the potential of cytokines to serve as biomarkers for CDI and predictors of disease severity. The systemic cytokine profiles of 36 CDI patients (20 with severe disease) and 8 healthy donors and the toxininduced cytokine profiles of peripheral blood mononuclear cells (PBMC) were determined. Further, we evaluated glucosyltransferase (GT) activity in regulation of toxininduced cytokine expression. We found upregulation of the majority of measured cytokines (11/20, 55%) in CDI patients. Interleukin-1 (IL-1), IL-6, IL-8, IL-17A, and IL-16 were the most upregulated. High serum levels of IL-2 and IL-15 were associated with a poor prognosis in CDI patients, whereas high levels of IL-5 and gamma interferon (IFN-␥) were associated with less severe disease. Both TcdA and TcdB were potent inducers of cytokine responses, as demonstrated by stimulation of a greater number and amount of cytokines. In addition to confirming prior reports on the role of IL-8, IL-1, and IL-6 in CDI, our data suggest that IL-16 and IL-17A, as well as the IL-1/Th17 axis, play a key role in driving inflammatory responses in CDI. A functional GT domain of C. difficile toxins was required for the induction of a majority of cytokines investigated.
Clostridioides difficile infections occur upon ecological / metabolic disruptions to the normal colonic microbiota, commonly due to broad-spectrum antibiotic use. Metabolism of bile acids through a 7α-dehydroxylation pathway found in select members of the healthy microbiota is regarded to be the protective mechanism by which C. difficile is excluded. These 7α-dehydroxylated secondary bile acids are highly toxic to C. difficile vegetative growth, and antibiotic treatment abolishes the bacteria that perform this metabolism. However, the data that supports the hypothesis that secondary bile acids protect against C. difficile infection is supported only by in vitro data and correlative studies. Here we show that bacteria that 7α-dehydroxylate primary bile acids protect against C. difficile infection in a bile acid-independent manner. We monoassociated germ-free, wildtype or Cyp8b1-/- (cholic acid-deficient) mutant mice and infected them with C. difficile spores. We show that 7α-dehydroxylation (i.e., secondary bile acid generation) is dispensable for protection against C. difficile infection and provide evidence that Stickland metabolism by these organisms consumes nutrients essential for C. difficile growth. Our findings indicate secondary bile acid production by the microbiome is a useful biomarker for a C. difficile-resistant environment but the microbiome protects against C. difficile infection in bile acid-independent mechanisms.
BACKGROUND & AIMS Chronic abdominal pain is the most common indication for esophagogastroduodenoscopy (EGD) in children. However, little is known about the accuracy of EGD-based diagnosis or the outcomes of the patients who undergo this procedure. We examined the diagnostic yield of EGD and short-term outcomes of children who underwent this procedure for chronic abdominal pain. METHODS We conducted a prospective study of 290 children (4–18 years old; mean age, 11.9 – 3.5 years; 93 girls) who underwent EGD for the primary indication of chronic abdominal pain (216 with at least 1 alarm feature) at a US pediatric gastroenterology referral center. We collected data on demographic features (age, sex), clinical characteristics (alarm features, Rome III criteria), and EGD results for each patient. All subjects with diagnostic lesions were followed for at least 1 year after EGD to determine short-term outcomes. RESULTS Overall, EGD provided an accurate diagnosis for 109 children (38%). Diagnoses included esophagitis (21.0%), eosinophilic gastroenteritis (4.1%), eosinophilic esophagitis (3.8%), Helicobacter pylori infection (2.0%), celiac disease (0.6%), and Crohn’s disease (0.4%). Short-term outcomes were available for 81% of patients with diagnostic findings, and medical therapy was effective in approximately 67% of these children. CONCLUSIONS EGD is valuable for the diagnosis of children with abdominal pain, with a 38% diagnostic yield. EGD identified disorders for which medical therapy was effective in 67% of children during the year after diagnosis.
Ethylmalonic encephalopathy (EE) is a rapidly progressive autosomal recessive mitochondrial disease caused by biallelic pathogenic variants in the ETHE1 gene that encodes the mitochondrial sulfur dioxygenase. It is characterized by neurodevelopmental delay and regression, pyramidal and extrapyramidal signs, recurrent petechiae, chronic diarrhea, and orthostatic acrocyanosis. Laboratory findings include elevated serum levels of lactate and C4-C5 acylcarnitines, and elevated urinary excretion of ethylmalonic acid and C4-C6 acylglycines, notably isobutyrylglycine and 2-methylbutyrylglycine. These findings are attributed to deficiency of the mitochondrial sulfur dioxygenase resulting in toxic accumulation of hydrogen sulfide metabolites in vascular endothelium and mucosal cells of the large intestine. Medical management has thus far been directed toward decreasing the accumulation of hydrogen sulfide metabolites using a combination of metronidazole and N-acetylcysteine. More recently, orthotopic liver transplant (OLT) has been reported as a new therapeutic option for EE. Here, we report two additional cases of EE who achieved psychomotor developmental improvement after 7-and 22-months following OLT. The second case serves as the longest developmental outcome follow-up reported, thus far, following OLT for EE. This report provides additional evidence to validate OLT as a promising therapeutic approach for what was considered to be a fatal disease. K E Y W O R D S ETHE1, ethylmalonic encephalopathy, hydrogen sulfide toxicity, mitochondrial sulfur dioxygenase, orthotopic liver transplant
Biliary atresia (BA), a chronic progressive cholestatic disease of infants, is the leading cause for liver transplant in children, especially in patients under two years of age. BA can be successfully treated with the Kasai portoenterostomy; however most patients still require a liver transplant, with up to one half of BA children needing a transplant by age two. In the current pediatric end-stage liver disease system, children with BA face the risk of not receiving a liver in a safe and timely manner. In this review, we discuss a number of possible solutions to help these children. We focus on two general approaches: (1) preventing/delaying need for transplantation, by optimizing the success of the Kasai operation; and (2) expediting transplantation when needed, by performing techniques other than the standard deceased-donor, whole, ABO-matched organ transplant.
Background: Biliary atresia's (BA) response to surgical Kasai portoenterostomy (KP) is uneven and dependent upon bile flow; 50% of infants require a liver transplant by 24 months. We hypothesized that the microbiome may identify and associate with outcomes in BA. Methods: Stool samples were collected from infants with cholestasis (n = 15), 8 of which with BA were followed longitudinally.16S sequencing was performed on all samples (n = 45). Whole Genome Sequencing (WGS) was performed on BA pre-KP samples (n = 8). Infants with BA, other forms of cholestasis, BA infants with very good bile flow (VGBF) and not (nVGBF) (VGBF dichotomized by TSBA <40 μmol/L by 6 months) were compared. Results: Of the 8 infants with BA, 4 infants had VGBF. Microbial richness was inversely proportional to degree of cholestasis (P = 0.046). Increased Bifidobacterium abundance associated with VGBF (P = 0.03) and decreased cholestasis (P < 0.01) at 1 month post-KP. Pre-KP, community structure differed in infants with BA versus other cholestasis. Interestingly, infants who subsequently achieved VGBF had increased diversity (P = 0.03) and different community structure at the pre-KP time point. WGS corroborated Bifidobacterium's pre-KP importance. Conclusions: The microbiome differs between infants with BA and other cholestasis. It additionally differs between infants with BA who have good and poor bile flow, and thus outcomes, post-KP. These differences are seen even before KP. These data suggest that bile influences the development of the infant microbiome and that there may be possible influences of the pre- and post-KP microbiome on bile flow after KP. Further larger studies are needed to confirm these findings.
http://aasldpubs.onlinelibrary.wiley.com/hub/journal/10.1002/(ISSN)2046-2484/video/15-s1-reading-tessier a video presentation of this article
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