Lipopolysaccharide-induced inflammation of bronchi and emphysematous changes of pulmonary parenchyma in miniature pigs (Sus scrofa domestica).

Lipopolysaccharide (LPS) is widely used to induce chronic obstructive pulmonary disease (COPD) in animal models. Rodents are most commonly used to model COPD, but their substantial anatomic and physiological differences from humans present a challenge in the research of COPD pathogenesis. The authors induced COPD in miniature pigs by intratracheal administration of LPS solution. They carried out bronchoalveolar lavage (BAL) and collected the fluid for analyses of white blood cells, cytokines and proteases and obtained lung tissues for histological assessment. Intratracheal administration of LPS caused bronchitis, obstruction of distal bronchi and damage of pulmonary alveoli, as well as increases in white blood cell counts and expression levels of cytokines and proteases. These results are consistent with the presentation of COPD in humans, making LPS administration in miniature pigs a valuable animal model for the research of pathogenesis and treatment of COPD.

Assessment of the modulating effects of fructo-oligosaccharides on fecal microbiota using human flora-associated piglets.

We first used human flora-associated (HFA) piglets, a significantly improved model for research on human gut microbiota, to study the effects of short-chain fructo-oligosaccharides (scFOS) on the gut bacterial populations. Ten neonatal HFA piglets were assigned to receive basal diets alone or supplemented with scFOS (0.5 g/kg body weight/day) from 1 to 37 days after birth (DAB). The impact of scFOS on the fecal bacterial populations of the piglets before (12 DAB), during (17 DAB), and after (25 and 37 DAB) weaning were monitored by PCR-denaturing gradient gel electrophoresis and real-time quantitative PCR. The Bifidobacterium genus was stimulated consistently, except during weaning, confirming the bifidogenic property of scFOS. At 12 DAB, the Clostridium leptum subgroup was decreased and two unknown Bacteroides-related species were increased; at 25 DAB, the C. leptum subgroup and Subdoligranulum variabile-like species were elevated, whereas one unknown Faecalibacterium-related species was suppressed; and at 37 DAB, the Bacteroides genus was decreased. The results showed that effects of scFOS on non-bifidobacteria varied at different developmental stages of the animals, warranting further investigation into the host-development-related effects of prebiotics on the gut microbiota and the host physiology using the HFA piglets as a model for humans.

Inhibition of porcine transmissible gastroenteritis virus (TGEV) replication in mini-pigs by shRNA.

Transmissible gastroenteritis virus (TGEV) is the causative agent of porcine transmissible gastroenteritis (TGE), characterized by high mortality and severely retarded growth in piglets that dramatically affects the porcine industry. Previously, we have identified two shRNA-expressing plasmids pEGFP-U6/P1 and pEGFP-U6/P2 that target RNA-dependent RNA polymerase (RdRP) gene of TGEV with more than 95% of virus inhibition in vitro. In this study, inhibition of the TGEV replication by pEGFP-U6/P1 and pEGFP-U6/P2 was tested in mini-pigs. SPF mini-pigs at 25 days old were injected with the shRNA-expressing plasmids and then infected with TGEV. The results from the analyses of clinical signs, histopathology, indirect immunofluorescence (IIF) and RT-PCR show that the two shRNA-expressing plasmids could significantly decrease the quantity of TGEV in different organs and protect mini-pigs from TGEV infection. These findings illustrate the prospect for TGEV-specific shRNAs to be new anti-TGEV agents.

Extended hepatectomy with segments I and VII as resection remnant: a simple model for small-for-size injuries in pigs.

BACKGROUND: Small-for-size (SFS) syndrome is an important clinical problem after living donor liver transplantation, split liver transplantation or extended hepatectomy. The uncertainty of the mechanisms and treatments of SFS syndrome urges surgeons to establish effective models for SFS syndrome. METHODS: A new porcine model for SFS syndrome based on extended hepatectomy was established. Portal pressure gradient was observed before and after the surgery, and venous sampling for estimation of alanine aminotransferase, total bilirubin, and international normalized ratio was continued on a daily basis. RESULTS: Although the external morphology of the porcine liver differs from that of human being, segmental anatomy is remarkably similar in term of its vascularity and biliary tree. Extended hepatectomy with segments I and VII as resection remnant (about 20% of total liver volume) resulted in similar survival rates, blood liver function tests, and elevated portal pressure gradient as clinical SFS syndrome. CONCLUSIONS: The extended hepatectomy based new model can easily be reproduced, with few costs and surgical complications. Clinical SFS syndrome can easily be simulated by this new model, which is a useful tool for studying SFS syndrome-related liver injuries, especially portal overperfusion and hypertension.

Fatal infection in human flora-associated piglets caused by the opportunistic pathogen Klebsiella pneumoniae from an apparently healthy human donor.

Seventeen out of 24 human flora-associated (HFA) piglets died after oral administration of whole fecal flora from an apparently healthy human donor. The bacteria isolated from the organs of the infected piglets were identified as Klebsiella pneumoniae by bacteriological and biochemical tests and 16S rRNA gene sequence analysis. The identical K. pneumoniae strain was also isolated from the donor's fecal flora. All three neonatal piglets inoculated with K. pneumoniae from the donor's fecal flora developed severe diarrhea, with 2 eventually dying. This strongly suggests that the opportunistic pathogen K. pneumoniae from the human donor caused the fatal infection in the HFA piglets. The results underscore the importance of safety evaluation of the human donor's fecal flora for HFA piglet development.

Inter-species transplantation of gut microbiota from human to pigs.

Direct research on gut microbiota for understanding its role as 'an important organ' in human individuals is difficult owing to its vast diversity and host specificity as well as ethical concerns. Transplantation of human gut microbiota into surrogate hosts can significantly facilitate the research of human gut ecology, metabolism and immunity but rodents-based model provides results with low relevance to humans. A new human flora-associated (HFA) piglet model was hereby established taking advantage of the high similarity between pigs and humans with respect to the anatomy, physiology and metabolism of the digestive system. Piglets were delivered via cesarean section into a SPF-level barrier system and were inoculated orally with a whole fecal suspension from one healthy 10-year-old boy. The establishment and composition of the intestinal microbiota of the HFA piglets were analyzed and compared with that of the human donor using enterobacterial repetitive intergenic consensus sequence-PCR fingerprinting-based community DNA hybridization, group-specific PCR-temperature gradient gel electrophoresis and real-time PCR. Molecular profiling demonstrated that transplantation of gut microbiota from a human to germfree piglets produced a donor-like microbial community with minimal individual variation. And the microbial succession with aging of those ex-germfree piglets was also similar to that observed in humans. This HFA model provides a significantly improved system for research on gut ecology in human metabolism, nutrition and drug discovery.

Molecular profiling of Bacteroides spp. in human feces by PCR-temperature gradient gel electrophoresis.

A group-specific PCR-based temperature gradient gel electrophoresis (TGGE) method was developed to study the population composition of genus Bacteroides in human gut. Highly reproducible and well-separated bands in TGGE fingerprints of ten unrelated human fecal samples showed complex and host-specific Bacteroides species composition. Dynamic monitoring over 22 months of samples from one healthy 10-year-old boy indicated a relatively stable population profile of Bacteroides. The species identity of each band in TGGE gel of this boy was also resolved via comigration analysis of sequenced inserts in a Bacteroides group-specific clone library. This work provides a rapid and effective technique for analyzing the species composition of Bacteroides in human gut.