Enteric viruses nucleic acids distribution along the digestive tract of rhesus macaques with idiopathic chronic diarrhea

Idiopathic chronic diarrhea (ICD) is a common clinical condition in captive rhesus macaques, claiming 33% of medical culls (i.e. deaths unrelated to research). Using viral metagenomics we characterized the eukaryotic virome in digestive tract tissues collected at necropsy from nine animals with ICD. We show the presence of multiple viruses in the Parvoviridae and Picornaviridae family. We then compared the distribution of viral reads in the stomach, duodenum, jejunum, ileum, and the proximal, transverse, and distal colons. Tissues and mucosal scraping from the same locations showed closely related results while different gut tissues from the same animal varied widely. Picornavirus reads were generally more abundant in the lower digestive tract, particularly in the descending (distal) colon. Parvoviruses were more abundant in the upper reach particularly in the stomach. In situ hydridization (ISH) of fixed tissues showed punctuated staining for both these RNA and DNA viruses in the distal colon. Parvovirus ISH staining was also detected in the stomach/duodenum/jejunum in distinct oval-shaped structures. Therefore, the location of enteric viral nucleic acid differed widely between different viral families and along the length of the digestive tract.

Whole tissue homogenization preferable to mucosal scraping in determining the temporal profile of segmented filamentous bacteria in the ileum of weanling rats

Segmented filamentous bacteria (SFB) are thought to play a role in small intestine immunological maturation. Studies in weanling mice have shown a positive correlation between ileal SFB abundance and plasma and faecal interleukin 17 (IL-17) and immunoglobulin A (IgA) concentrations. Although the first observation of SFB presence was reported in rats, most studies use mice. The size of the mouse ileum is a limitation whereas the rat could be a suitable alternative for sufficient samples. Changes in SFB abundance over time in rats were hypothesized to follow the pattern reported in mice and infants. We characterized the profile of SFB colonization in the ileum tissue and contents and its correlation with two immune markers of gastrointestinal tract (GIT) maturation. We also compared two published ileum collection techniques to determine which yields data on SFB abundance with least variability. Whole ileal tissue and ileal mucosal scrapings were collected from 20- to 32-day-old Sprague-Dawley rats. SFB abundance was quantified from proximal, middle and distal ileal tissues, contents and faeces by quantitative PCR using SFB-specific primers. Antibody-specific ELISAs were used to determine IL-17 and IgA concentrations. Significant differences in SFB abundance were observed from whole and scraped tissues peaking at day 22. Variability in whole ileum data was less, favouring it as a better collection technique. A similar pattern of SFB abundance was observed in ileum contents and faeces peaking at day 24, suggesting faeces can be a proxy for ileal SFB abundance. SFB abundance at day 26 was higher in females than males across all samples. There were significant differences in IgA concentration between days 20, 30 and 32 and none in IL-17 concentration, which was different from reports in mice and infants.

A209 ROLE OF SEROTONIN-AUTOPHAGY AXIS IN REGULATION OF EPITHELIAL CELL FUNCTION AND MICROBIOTA COMPOSITION IN GUT

Background Serotonin (5-hydroxytryptamine; 5-HT), an enteric signalling molecule mainly produced by the enterochromaffin (EC) cells of the intestinal epithelium regulates various processes of the gut. Tryptophan hydroxylase 1 (Tph1) is the rate-limiting enzyme of 5-HT biosynthesis in EC cells. In inflammatory bowel disease (IBD) and experimental colitis, there are alterations in 5-HT content and microbiota composition in the gut. Previously we reported, Tph1-deficient (Tph1-/-) mice with reduced 5-HT in the gut exhibit reduced susceptibility to colitis. The mechanism by which 5-HT regulates colitis is unknown. Autophagy, a catabolic process regulates the function of intestinal epithelial cells (IECs), gut microbiota, and protects against intestinal inflammation. Both aberrant 5-HT signalling and autophagy is implicated in colitis. It is unclear whether they interact in regulation of production of pro-inflammatory cytokines from IECs and gut microbiota composition in relation to colitis. Our hypothesis is, an increase in 5-HT signalling inhibits autophagy in the IECs, which results in up-regulation of colitis by increasing the production of pro-inflammatory cytokines, and by selection for a more colitogenic microbiota. Aims To define the role of 5-HT-autophagy axis in the production of pro-inflammatory cytokines from IECs and gut microbiota composition in intestinal inflammation. Methods We investigated level of autophagy with or without 5% dextran sodium sulphate (DSS) in colons, mucosal scraping and IECs of Tph1-/- and their wild-type (WT) littermates. In addition, autophagy and proinflammatory cytokine production were investigated in human colonic epithelial cells (HT-29) following stimulation by 5-HT. We evaluated colitis and gut microbiota composition in WT, Tph1-/-, epithelial-specific autophagy gene Atg7 deficient (Atg7ΔIEC), and Atg7ΔIECTph1-/- (double knock out; DKO) mice. Results Tph1 -/- mice, with less 5-HT in the gut than WT mice following DSS administration exhibited an up-regulation of autophagy markers in the colon, mucosal scraping and IECs along with reduction of colitis severity. 5-HT treatment of HT-29 cells resulted in down-regulation of autophagy and upregulation of pro-inflammatory cytokine, IL-8. DKO mice exhibited increased severity of DSS-colitis, and altered microbiota composition compared to Tph1-/- mice. Conclusions These findings suggest, an increase in 5-HT in colitis inhibits autophagy in the IECs that contribute to alteration of the gut microbiota and disease severity. Blocking 5-HT signalling may promote autophagy in the IECs and alleviate the severity of colitis. Understanding the contribution of 5-HT in autophagy may identify new therapeutic target in IBD and other intestinal inflammatory conditions that exhibit dysregulated autophagy. Funding Agencies CAG, CIHR

Isolation and Genotyping Study of Clostridium Perfringens From Broiler Farms Infected with Necrotic Enteritis in Sulaimania Province

The study is conducting to isolate and toxinotype the suspected cases of Clostridium perfringens infections of broiler farms in Sulaimania province. A total of 108 samples were collected from intestinal contents, mucosal scraping, and hemorrhagic lymphoid nodules from suspected cases of necrotic enteritis in broilers. The result of isolated and identified bacteria were revealed that 63 (58%) out of 108 samples were positive for C. perfringens. The results revealed that the isolates were only positive for alpha and beta2 toxin genes. Phylogenetic and DNA sequence analysis of cpa and cpb2 gene showed that cpa genes were highly identical to isolates from broiler in Iran, poultry stool and broiler in Brazil, and blue calves in Belgium. While cpb2 gene is closely related to the isolates of broiler in Iran, India and isolates of goat in Pakistan. The results indicated that the causative agent of necrotic enteritis in broiler farms in the region was mainly due to C. perfringens type A infection

Evaluation of a coproantigen enzyme-linked immunosorbent assay for the diagnosis of canine echinococcosis in Iran

Echinococcosis is one of the most important zoonosis in Iran. Due to this fact that providing a reliable diagnostic method for detection of this infection in definitive host is a critical prerequirement for the establishment of appropriate control programs in our country, one hundred and sixteen carnivores including 80 dogs, 27 jackals, 8 foxes and one wolf were collected from rural areas of Hamadan, Azarbaijan and Tehran provinces and examined for Echinococcus granulosus infection. Canine echinococcosis was diagnosed upon direct microscopic examination of intestinal contents and mucosal scraping for adult tapeworms, and a coproantigen detection enzyme linked immunosorbent assay (CA-ELISA) for Echinococcus granulosus. The overall prevalence of canine echinococcosis using the ELISA test was 43.1 % (50/116). The relative frequency of canine echinococcosis was 37 % (43/116) by microscopic examination.The sensitivity and specificity of the CA-ELISA test as referenced by necropsy findings was 72.1 % and 74 % respectively. We found this assay to be a very suitable and advantageous method for the surveillance of canine population especially in regions with endemic echinococcosis.