Myoelectric activity of the ileum, cecum, proximal loop of the ascending colon, and spiral colon in cows with naturally occurring cecal dilatation-dislocation

OBJECTIVE: To analyze myoelectric activity of the ileum, cecum, proximal loop of the ascending colon (PLAC), and spiral colon in cows with naturally occurring cecal dilatation-dislocation (CDD) and compare findings with those in healthy cows. ANIMALS: 8 CDD-affected and 6 healthy control cows. PROCEDURES: Immediately after diagnosis, CDD-affected cows underwent surgery; control cows underwent a similar surgical procedure. Before completion of surgery, 8 bipolar silver electrodes were implanted in the ileum (n = 2), cecum (1), PLAC (1), and spiral colon (4) of each cow. Beginning the day after surgery, intestinal myoelectric activity was recorded daily (8-hour period) for 4 days; data were analyzed by use of specialized software programs. Quantitative variables of myoelectric activity were compared between groups. RESULTS: Cows of both groups recovered without complications after surgery. In control cows, physiologic myoelectric activity was recorded in all intestinal segments on all days after surgery. Apparently normal myoelectric activity was evident in the ileum of CDD-affected cows on the first day after surgery, but myoelectric activity patterns in the cecum, PLAC, and spiral colon were variable with no organized cyclic myoelectric patterns, incomplete or normally organized migrating myoelectric complexes, and slow normalization over time. CONCLUSIONS AND CLINICAL RELEVANCE: After surgery for CDD, normal myoelectric patterns were disrupted in the large intestine of cows, especially in the spiral colon. Clinical recovery with effective transit of ingesta occurred before normalization of myoelectric activity in the large intestine. Therapeutic protocols for restoration or normalization of spiral colon motility should be developed for treatment of CDD-affected cattle.

Quantitative mRNA analysis of adrenergic receptor subtypes in the intestines of healthy dairy cows and dairy cows with cecal dilatation-dislocation

OBJECTIVE: To investigate the distribution of mRNA coding for 9 adrenoceptor subtypes in the intestines of healthy dairy cows and cows with cecal dilatationdislocation (CDD). SAMPLE POPULATION: Full-thickness specimens of the intestinal wall were obtained from the ileum, cecum, proximal loop of the ascending colon (PLAC), and external loop of the spiral colon (ELSC) of 15 cows with CDD (group 1) and 15 healthy (control) cows (group 2, specimens collected during laparotomy; group 3, specimens collected after slaughter). PROCEDURES: Concentrations of mRNA for 9 adrenoceptor subtypes (alpha(1A), alpha(1B), alpha(1D), alpha(2AD), alpha(2B), alpha(2C), beta(1), beta(2), and beta(3)) were measured by quantitative real-time reverse transcriptase-PCR assay. Results were expressed relative to mRNA expression of a housekeeping gene. RESULTS: Expression of mRNA for alpha(1B)-, alpha(2AD)-, alpha(2B)-, beta(1)-, and beta(2)-adrenoceptors was significantly lower in cows with CDD than in control cows. In the ileum, these receptors all had lower mRNA expression in cows with CDD than in control cows. The same effect was detected in the ELSC for mRNA for alpha(2AD)-, alpha(2B)-, beta(1)-, and beta(2)-adrenoceptors, and in the cecum and PLAC for alpha(2B)- and beta(2)-adrenoceptors. Groups did not differ significantly for alpha(1A)-adrenoceptors. The mRNA expression for alpha(1D)-, alpha(2C)-, and beta(3)-adrenoceptors was extremely low in all groups. CONCLUSIONS AND CLINICAL RELEVANCE: Differences in expression of mRNA coding for adrenoceptors, most pronounced in the ileum and spiral colon, between cows with CDD and control cows support the hypothesis of an implication of adrenergic mechanisms in the pathogenesis of CDD in dairy cows.

Distribution of mRNA coding for 5-hydroxytryptamine receptor subtypes in the intestines of healthy dairy cows and dairy cows with cecal dilatation-dislocation

OBJECTIVE: To investigate the distribution of mRNA coding for 7 subtypes of 5-hydroxytryptamine receptors (5-HTRs) in the intestines of healthy dairy cows and dairy cows with cecal dilatation-dislocation (CDD). SAMPLE POPULATION: Full-thickness intestinal wall biopsy specimens were obtained from the ileum, cecum, proximal loop of the ascending colon, and external loop of the spiral colon (ELSC) of 15 cows with CDD (group 1) and 15 healthy dairy cows allocated to 2 control groups (specimens collected during routine laparotomy [group 2] or after cows were slaughtered [group 3]). PROCEDURE: Amounts of mRNA coding for 7 subtypes of 5-HTRs (5-HT1A, 5-HT1B, 5-HT1D, 5-HT1F, 5-HT2A, 5-HT2B, and 5-HT4) were measured by quantitative real-time reverse transcriptase-PCR assay. Results were expressed as the percentage of mRNA expression of a housekeeping gene. RESULTS: Expression of mRNA coding for 5-HTR1B, 5-HTR2B, and 5-HTR4 was significantly lower in cows with CDD than in healthy cows. For 5-HTR2B and 5-HTR4, significant differences between cows with CDD and control cows were most pronounced for the ELSC. Expression of mRNA for 5-HTR1D, 5-HTR1F, and 5-HTR2A was extremely low in all groups, and mRNA for 5-HTR1A was not detected. CONCLUSIONS AND CLINICAL RELEVANCE: Relative concentrations of mRNA coding for 5-HTR1B, 5-HT2B, and 5-HTR4 were significantly lower in the intestines of cows with CDD than in the intestines of healthy dairy cows, especially for 5-HT2B and 5-HTR4 in the ELSC. This supports the hypothesis that serotonergic mechanisms, primarily in the spiral colon, are implicated in the pathogenesis of CDD.

Assessment of the excretion time of electronic capsules placed in the intestinal lumen of cows with cecal dilatation-dislocation, healthy control cows, and cows with left displacement of the abomasum

OBJECTIVE To analyze the transit time from various locations in the intestines of cows with cecal dilatation-dislocation (CDD), healthy control cows, and cows with left displacement of the abomasum (LDA). ANIMALS 15 cows with naturally occurring CDD (group 1), 14 healthy control cows (group 2), and 18 cows with LDA (group 3). PROCEDURES 5 electronic transmitters were encased in capsules and placed in the lumen of the ileum, cecum, proximal portion of the colon, and 2 locations in the spiral colon (colon 1 and colon 2) and used to measure the transit time (ie, time between placement in the lumen and excretion of the capsules from the rectum). Excretion time of the capsules from each intestinal segment was compared among groups. RESULTS Cows recovered well from surgery, except for 1 cow with relapse of CDD 4 days after surgery and 2 cows with incisional infection. High variability in capsule excretion times was observed for all examined intestinal segments in all groups. Significant differences were detected for the excretion time from the colon (greater in cows with CDD than in healthy control cows) and cecum (less in cows with LDA than in cows of the other 2 groups). CONCLUSIONS AND CLINICAL RELEVANCE The technique developed to measure excretion time of capsules from bovine intestines was safe and reliable; however, the large variability observed for all intestinal segments and all groups would appear to be a limitation for its use in assessment of intestinal transit time of cattle in future studies.

Ceco-cecal intussusception in a Simmental heifer

This report describes the clinical, laboratory and ultrasonographic findings in a Simmental heifer with a ceco-cecal intussusception. The general condition of the heifer was moderately reduced and it showed mild colic signs. Physical examination revealed a firm longish mass visible and palpable in the right flank. Findings upon rectal examination, fecal output und defecation were normal. Ultrasound examination of the mass revealed features typical for an intussusception. Based on the slow development of symptoms, normal fecal output and ultrasonography findings, a ceco-cecal intussusception was diagnosed. Right flank laparatomy was performed under general anaesthesia, and an end-to-side anastomosis between the jejunum and the spiral colon was made after resection of the intussuscepted intestines. Recovery was uneventful.

Caspase-3 mediates in part hippocampal apoptosis in sepsis

The brain is one of the first organs affected during sepsis development resulting in apoptosis for a short-term and cognitive impairment for a long-term. Despite its importance, the mechanisms of brain dysfunction during sepsis are not fully elucidated. Thus, we here, in an animal model of sepsis, evaluated apoptosis in the dentate gyrus cell layer of the hippocampus to document the involvement of caspase-3 in the pathogenesis of neuronal apoptosis. Wistar rats sham-operated or submitted to the cecal ligation and perforation (CLP) procedure were killed at 12, 24, 48 h, and 10 days after surgery for the determination of caspase-3 and apoptosis rate. In a separate cohort of animals, a caspase-3-specific inhibitor was administered and animals were killed at 12 h after sepsis. An increase in the number of apoptotic cells 12, 24, and 48 h by histopathological evaluations and an increase of caspase-3 apoptotic cells 12 and 24 h after sepsis induction were observed. The caspase-3 inhibitor decreases the number of apoptotic cells by histopathological evaluations but not by immunohistochemistry evaluations. Caspase-3 is involved in part in apoptosis in the dentate gyrus cell layer of the hippocampus in septic rats submitted by CLP.

Generation and analysis of a mouse intestinal metatranscriptome through Illumina based RNA-sequencing

With the advent of high through-put sequencing (HTS), the emerging science of metagenomics is transforming our understanding of the relationships of microbial communities with their environments. While metagenomics aims to catalogue the genes present in a sample through assessing which genes are actively expressed, metatranscriptomics can provide a mechanistic understanding of community inter-relationships. To achieve these goals, several challenges need to be addressed from sample preparation to sequence processing, statistical analysis and functional annotation. Here we use an inbred non-obese diabetic (NOD) mouse model in which germ-free animals were colonized with a defined mixture of eight commensal bacteria, to explore methods of RNA extraction and to develop a pipeline for the generation and analysis of metatranscriptomic data. Applying the Illumina HTS platform, we sequenced 12 NOD cecal samples prepared using multiple RNA-extraction protocols. The absence of a complete set of reference genomes necessitated a peptide-based search strategy. Up to 16% of sequence reads could be matched to a known bacterial gene. Phylogenetic analysis of the mapped ORFs revealed a distribution consistent with ribosomal RNA, the majority from Bacteroides or Clostridium species. To place these HTS data within a systems context, we mapped the relative abundance of corresponding Escherichia coli homologs onto metabolic and protein-protein interaction networks. These maps identified bacterial processes with components that were well-represented in the datasets. In summary this study highlights the potential of exploiting the economy of HTS platforms for metatranscriptomics.

Distribution of muscarinic receptor subtypes and interstitial cells of Cajal in the gastrointestinal tract of healthy dairy cows

OBJECTIVE: To describe the distribution of muscarinic receptor subtypes M(1) to M(5) and interstitial cells of Cajal (ICCs) in the gastrointestinal tract of healthy dairy cows. SAMPLE POPULATION: Full-thickness samples were collected from the fundus, corpus, and pyloric part of the abomasum and from the duodenum, ileum, cecum, proximal loop of the ascending colon, and both external loops of the spiral colon of 5 healthy dairy cows after slaughter. PROCEDURES: Samples were fixed in paraformaldehyde and embedded in paraffin. Muscarinic receptor subtypes and ICCs were identified by immunohistochemical analysis. RESULTS: Staining for M(1) receptors was found in the submucosal plexus and myenteric plexus. Antibodies against M(2) receptors stained nuclei of smooth muscle cells only. Evidence of M(3) receptors was found in the lamina propria, in intramuscular neuronal terminals, on intermuscular nerve fibers, and on myocytes of microvessels. There was no staining for M(4) receptors. Staining for M(5) receptors was evident in the myocytes of microvessels and in smooth muscle cells. The ICCs were detected in the myenteric plexus and within smooth muscle layers. Distribution among locations of the bovine gastrointestinal tract did not differ for muscarinic receptor subtypes or ICCs. CONCLUSIONS AND CLINICAL RELEVANCE: The broad distribution of M(1), M(3), M(5), and ICCs in the bovine gastrointestinal tract indicated that these components are likely to play an important role in the regulation of gastrointestinal tract motility in healthy dairy cows. Muscarinic receptors and ICCs may be implicated in the pathogenesis of motility disorders, such as abomasal displacement and cecal dilatation-dislocation.

Continuous thoracic epidural anesthesia improves gut mucosal microcirculation in rats with sepsis

Microcirculatory dysfunction contributes significantly to tissue hypoxia and multiple organ failure in sepsis. Ischemia of the gut and intestinal hypoxia are especially relevant for the evolution of sepsis because the mucosal barrier function may be impaired, leading to translocation of bacteria and toxins. Because sympathetic blockade enhances intestinal perfusion under physiologic conditions, we hypothesized that thoracic epidural anesthesia (TEA) may attenuate microcirculatory perturbations during sepsis. The present study was designed as a prospective and controlled laboratory experiment to assess the effects of continuous TEA on the mucosal microcirculation in a cecal ligation and perforation model of sepsis in rats. Anesthetized Sprague-Dawley rats underwent laparotomy and cecal ligation and perforation to induce sepsis. Subsequently, either bupivacaine 0.125% (n = 10) or isotonic sodium chloride solution (n = 9) was continuously infused via the thoracic epidural catheter for 24 h. In addition, a sham laparotomy was carried out in eight animals. Intravital videomicroscopy was then performed on six to ten villi of ileum mucosa. The capillary density was measured as areas encircled by perfused capillaries, that is, intercapillary areas. The TEA accomplished recruitment of microcirculatory units in the intestinal mucosa by decreasing total intercapillary areas (1,317 +/- 403 vs. 1,001 +/- 236 microm2) and continuously perfused intercapillary areas (1,937 +/- 512 vs. 1,311 +/- 678 microm2, each P < 0.05). Notably, TEA did not impair systemic hemodynamic variables beyond the changes caused by sepsis itself. Therefore, sympathetic blockade may represent a therapeutic option to treat impaired microcirculation in the gut mucosa resulting from sepsis. Additional studies are warranted to assess the microcirculatory effects of sympathetic blockade on other splanchnic organs in systemic inflammation.

Human microbiota-secreted factors inhibit shiga toxin synthesis by enterohemorrhagic Escherichia coli O157:H7

Escherichia coli O157:H7 is a food-borne pathogen causing hemorrhagic colitis and hemolytic-uremic syndrome, especially in children. The main virulence factor responsible for the more serious disease is the Shiga toxin 2 (Stx2), which is released in the gut after oral ingestion of the organism. Although it is accepted that the amount of Stx2 produced by E. coli O157:H7 in the gut is critical for the development of disease, the eukaryotic or prokaryotic gut factors that modulate Stx2 synthesis are largely unknown. In this study, we examined the influence of prokaryotic molecules released by a complex human microbiota on Stx2 synthesis by E. coli O157:H7. Stx2 synthesis was assessed after growth of E. coli O157:H7 in cecal contents of gnotobiotic rats colonized with human microbiota or in conditioned medium having supported the growth of complex human microbiota. Extracellular prokaryotic molecules produced by the commensal microbiota repress stx(2) mRNA expression and Stx2 production by inhibiting the spontaneous and induced lytic cycle mediated by RecA. These molecules, with a molecular mass of below 3 kDa, are produced in part by Bacteroides thetaiotaomicron, a predominant species of the normal human intestinal microbiota. The microbiota-induced stx(2) repression is independent of the known quorum-sensing pathways described in E. coli O157:H7 involving SdiA, QseA, QseC, or autoinducer 3. Our findings demonstrate for the first time the regulatory activity of a soluble factor produced by the complex human digestive microbiota on a bacterial virulence factor in a physiologically relevant context.

Catapult-like release of mitochondrial DNA by eosinophils contributes to antibacterial defense

Although eosinophils are considered useful in defense mechanisms against parasites, their exact function in innate immunity remains unclear. The aim of this study is to better understand the role of eosinophils within the gastrointestinal immune system. We show here that lipopolysaccharide from Gram-negative bacteria activates interleukin-5 (IL-5)- or interferon-gamma-primed eosinophils to release mitochondrial DNA in a reactive oxygen species-dependent manner, but independent of eosinophil death. Notably, the process of DNA release occurs rapidly in a catapult-like manner--in less than one second. In the extracellular space, the mitochondrial DNA and the granule proteins form extracellular structures able to bind and kill bacteria both in vitro and under inflammatory conditions in vivo. Moreover, after cecal ligation and puncture, Il5-transgenic but not wild-type mice show intestinal eosinophil infiltration and extracellular DNA deposition in association with protection against microbial sepsis. These data suggest a previously undescribed mechanism of eosinophil-mediated innate immune responses that might be crucial for maintaining the intestinal barrier function after inflammation-associated epithelial cell damage, preventing the host from uncontrolled invasion of bacteria.

Elevated levels of placental growth factor represent an adaptive host response in sepsis

Recently, we demonstrated that circulating levels of vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) are increased in sepsis (Yano, K., P.C. Liaw, J.M. Mullington, S.C. Shih, H. Okada, N. Bodyak, P.M. Kang, L. Toltl, B. Belikoff, J. Buras, et al. 2006. J. Exp. Med. 203:1447-1458). Moreover, enhanced VEGF/Flk-1 signaling was shown to contribute to sepsis morbidity and mortality. We tested the hypothesis that PlGF also contributes to sepsis outcome. In mouse models of endotoxemia and cecal ligation puncture, the genetic absence of PlGF or the systemic administration of neutralizing anti-PlGF antibodies resulted in higher mortality compared with wild-type or immunoglobulin G-injected controls, respectively. The increased mortality associated with genetic deficiency of PlGF was reversed by adenovirus (Ad)-mediated overexpression of PlGF. In the endotoxemia model, PlGF deficiency was associated with elevated circulating levels of VEGF, induction of VEGF expression in the liver, impaired cardiac function, and organ-specific accentuation of barrier dysfunction and inflammation. Mortality of endotoxemic PlGF-deficient mice was increased by Ad-mediated overexpression of VEGF and was blocked by expression of soluble Flt-1. Collectively, these data suggest that up-regulation of PlGF in sepsis is an adaptive host response that exerts its benefit, at least in part, by attenuating VEGF signaling.

Aseptic intussuscepted incidental appendectomy: three successful cases

BACKGROUND: Incidental appendectomy remains a controversial issue. We aimed to collect experience using a modified surgical technique that could be applied securely in infants. METHODS: We performed aseptic intussuscepted incidental appendectomy (AIIA) in three patients using a technique that is thought to assure appendix necrosis along with intact cecal wall. RESULTS: There was no perioperative morbidity due to AIIA in the three patients. In two infants the necrotic appendix was found in the diaper. One infant died secondary to diaphragmatic hernia. Autopsy with histological examination revealed that the cecum was intact along with appendix necrosis. CONCLUSIONS: Modified AIIA could securely be performed in the 3 reported cases. We advocate prospective evaluation of the method.

Mesenchymal stromal cells improve survival during sepsis in the absence of heme oxygenase-1: the importance of neutrophils

The use of mesenchymal stromal cells (MSCs) for treatment of bacterial infections, including systemic processes like sepsis, is an evolving field of investigation. This study was designed to investigate the potential use of MSCs, harvested from compact bone, and their interactions with the innate immune system, during polymicrobial sepsis induced by cecal ligation and puncture (CLP). We also wanted to elucidate the role of endogenous heme oxygenase (HO)-1 in MSCs during a systemic bacterial infection. MSCs harvested from the bones of HO-1 deficient (-/-) and wild-type (+/+) mice improved the survival of HO-1(-/-) and HO-1(+/+) recipient mice when administered after the onset of polymicrobial sepsis induced by CLP, compared with the administration of fibroblast control cells. The MSCs, originating from compact bone in mice, enhanced the ability of neutrophils to phagocytize bacteria in vitro and in vivo and to promote bacterial clearance in the peritoneum and blood after CLP. Moreover, after depleting neutrophils in recipient mice, the beneficial effects of MSCs were entirely lost, demonstrating the importance of neutrophils for this MSC response. MSCs also decreased multiple organ injury in susceptible HO-1(-/-) mice, when administered after the onset of sepsis. Taken together, these data demonstrate that the beneficial effects of treatment with MSCs after the onset of polymicrobial sepsis is not dependent on endogenous HO-1 expression, and that neutrophils are crucial for this therapeutic response.