Name: ex vivo intestinal sacs to assess mucosal permeability in models of gastrointestinal disease
Uploaded: 2016-02-09T13:00:00
Description: Watch this Scientific Journal Video about Ex Vivo Intestinal Sacs to Assess Mucosal Permeability in Models of Gastrointestinal Disease at JoVE.com

This work was funded by National Health and Medical Research Project Grant APP1021582 and a Hunter Medical Research Institute grant sponsored by Sparke Helmore/NBN Triathlon and the Estate of the late Leslie Kenneth McFarlane.

All animal work in this protocol is performed with strict adherence to University of Newcastle Animal Ethics Committee approved procedures.
1. Preparation of Instruments, Culture Media and Dishes
<ol>
	<li>Pre-warm Media 199 (TC199) or Dulbecco&#39;s Modified Eagle Medium (DMEM) media to 37 &#176;C. Pre-oxygenate the medium by bubbling with 95% O2/5% CO2. Check that the medium has a final pH of 7.3.</li>
	<li>Prepare suture by cutting two 5 cm sections for ea...

<ol>
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H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antimicrobial+peptides+in+innate+immunity+of+the+human+intestine.">Antimicrobial peptides in innate immunity of the human intestine.</a> Journal of gastroenterology. 38, 717-726 (2003).</li><li>Robinson, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mucosal+protection+by+hypoxia-inducible+factor+prolyl+hydroxylase+inhibition.">Mucosal protection by hypoxia-inducible factor prolyl hydroxylase inhibition.</a> Gastroenterology. 134, 145-155 (2008).</li><li>Feighery, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+intestinal+permeability+in+rats+subjected+to+traumatic+frontal+lobe+percussion+brain+injury.">Increased intestinal permeability in rats subjected to traumatic frontal lobe percussion brain injury.</a> The Journal of trauma. 64, 131-137 (2008).</li><li>Keely, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chloride-led+disruption+of+the+intestinal+mucous+layer+impedes+Salmonella+invasion:+evidence+for+an+'enteric+tear'+mechanism.">Chloride-led disruption of the intestinal mucous layer impedes Salmonella invasion: evidence for an 'enteric tear' mechanism.</a> Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology. 28, 743-752 (2011).</li><li>Keely, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Contribution+of+epithelial+innate+immunity+to+systemic+protection+afforded+by+prolyl+hydroxylase+inhibition+in+murine+colitis.">Contribution of epithelial innate immunity to systemic protection afforded by prolyl hydroxylase inhibition in murine colitis.</a> Mucosal immunology. 7, 114-123 (2014).</li><li>Sourisseau, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+PCNA+and+cyclin+D1+expression+and+epithelial+morphogenesis+by+the+ZO-1-regulated+transcription+factor+ZONAB/DbpA.">Regulation of PCNA and cyclin D1 expression and epithelial morphogenesis by the ZO-1-regulated transcription factor ZONAB/DbpA.</a> Mol Cell Biol. 26, 2387-2398 (2006).</li><li>Ruehl-Fehlert, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Revised+guides+for+organ+sampling+and+trimming+in+rats+and+mice--part+1.">Revised guides for organ sampling and trimming in rats and mice--part 1.</a> Exp Toxicol Pathol. 55, 91-106 (2003).</li><li>Barthe, L., Woodley, J. 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J., Bzik, V. A., Lewis, A. L., Illum, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CriticalSorb+promotes+permeation+of+flux+markers+across+isolated+rat+intestinal+mucosae+and+Caco-2+monolayers.">CriticalSorb promotes permeation of flux markers across isolated rat intestinal mucosae and Caco-2 monolayers.</a> Pharmaceutical research. 29, 2543-2554 (2012).</li><li>Hubbard, D., Ghandehari, H., Brayden, D. 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I. Studies in isolated rat and human colonic mucosae.</a> European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences. 38, 291-300 (2009).</li><li>Balda, M. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+dissociation+of+paracellular+permeability+and+transepithelial+electrical+resistance+and+disruption+of+the+apical-basolateral+intramembrane+diffusion+barrier+by+expression+of+a+mutant+tight+junction+membrane+protein.">Functional dissociation of paracellular permeability and transepithelial electrical resistance and disruption of the apical-basolateral intramembrane diffusion barrier by expression of a mutant tight junction membrane protein.</a> The Journal of cell biology. 134, 1031-1049 (1996).</li><li>Behrens, I., Stenberg, P., Artursson, P., Kissel, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transport+of+lipophilic+drug+molecules+in+a+new+mucus-secreting+cell+culture+model+based+on+HT29-MTX+cells.">Transport of lipophilic drug molecules in a new mucus-secreting cell culture model based on HT29-MTX cells.</a> Pharmaceutical research. 18, 1138-1145 (2001).</li><li>Stefka, A. 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Here, we have detailed the isolation and preparation of intestinal sacs to assess mucosal barrier function ex vivo. Intestinal sac preparations have primarily been utilized in pharmaceutical research, examining the absorption of candidate drugs across the intestine. However, this assay is equally well suited for the study of intestinal disease. Intestinal permeability may vary greatly by region and site specific assessment of permeability allows a better understanding of the regional importance of mucosal integr...

The intestinal epithelial barrier of the gastrointestinal tract is a mucosal surface area estimated at 400 m2 in the human adult. Consequently, it is constantly exposed to challenge from microbes, ingested drugs, nutrients and bacterial toxins. The host must not only distinguish between tolerable commensal bacteria and potential pathogens, but must prevent these species and their secreted molecules from crossing the epithelial barrier, while at the same time allowing absorption of nutrients. Thus, the role of the intestinal epithelium is to act as a selective barrier to the luminal contents 1. This is achieved, in part, by the innate epithelial defense system at the mucosa, which acts through a responsive biological system consisting of constitutive and inducible mechanisms 2.
Loss of epithelial barrier function is a pathology that is characteristic of a number of gastrointestinal diseases. In vivo examination of epithelial barrier function may be assessed through oral gavage of a tracer molecule and subsequent serum analysis 3. However, this technique offers no indication as to the site of barrier dysfunction. In vitro and ex vivo assessment of transepithelial resistance using Transwell systems 3 and Ussing chambers 4,5 respectively, are commonly employed as surrogate markers of epithelial barrier function, but lack the contributing disease physiology of animal models 6. In this protocol we describe an ex vivo tissue preparation model that allows direct and localized assessment of intestinal integrity and which may be used to assess mucosal barrier function at a number of levels. Importantly, this technique may be applied to animal models of disease, or may be pharmacologically manipulated to allow in depth interrogation of mucosal barrier dysfunction.

<table border="0" cellpadding="0" cellspacing="0" width="904">
	<tbody>
		<tr height="43">
			<td height="43" style="height:43px;width:227px;">Dekantel&#160; Non-absorbable Silk suture</td>
			<td style="width:227px;">Braintree Scientific</td>
			<td style="width:227px;">SUT-S 116</td>
			<td style="width:227px;"></td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:227px;">Media 199 (TC199)&#160;</td>
			<td style="width:227px;">Life Technologies</td>
			<td style="width:227px;">11043-023</td>
			<td style="width:227px;">No phenol red as this interferes with fluorescence</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:227px;">Dulbecco&#39;s Modified Eagle Medium (DMEM)</td>
			<td style="width:227px;">Life Technologies</td>
			<td style="width:227px;">21063-045</td>
			<td style="width:227px;">No phenol red as this interferes with fluorescence</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:227px;">N-acetylcysteine</td>
			<td style="width:227px;">Sigma Aldrich</td>
			<td style="width:227px;"></td>
			<td style="width:227px;">Use at 10mM in media</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:227px;">Small animal vascular cathether: Physiocath</td>
			<td style="width:227px;">Data Sciences International</td>
			<td style="width:227px;">277-1-002</td>
			<td style="width:227px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:227px;">FITC-Dextran 4400 MW</td>
			<td style="width:227px;">Sigma Aldrich</td>
			<td style="width:227px;">FD-4</td>
			<td style="width:227px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:227px;">FITC-Dextran 20,000 MW</td>
			<td style="width:227px;">Sigma Aldrich</td>
			<td style="width:227px;">FD-20</td>
			<td style="width:227px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:227px;">FITC-Dextran 70,000 MW</td>
			<td style="width:227px;">Sigma Aldrich</td>
			<td style="width:227px;">FD-70</td>
			<td style="width:227px;"></td>
		</tr>
	</tbody>
</table>

ex vivo intestinal sacs to assess mucosal permeability in models of gastrointestinal disease

The epithelial barrier is the first innate defense of the gastrointestinal tract and selectively regulates transport from the lumen to the underlying tissue compartments, restricting the transport of smaller molecules across the epithelium and almost completely prohibiting epithelial macromolecular transport. This selectivity is determined by the mucous gel layer, which limits the transport of lipophilic molecules and both the apical receptors and tight junctional protein complexes of the epithelium. In vitro cell culture models of the epithelium are convenient, but as a model, they lack the complexity of interactions between the microbiota, mucous-gel, epithelium and immune system. On the other hand, in vivo assessment of intestinal absorption or permeability may be performed, but these assays measure overall gastrointestinal absorption, with no indication of site specificity. Ex vivo permeability assays using &#34;intestinal sacs&#34; are a rapid and sensitive method of measuring either overall intestinal integrity or comparative transport of a specific molecule, with the added advantage of intestinal site specificity. Here we describe the preparation of intestinal sacs for permeability studies and the calculation of the apparent permeability (Papp) of a molecule across the intestinal barrier. This technique may be used as a method of assessing drug absorption, or to examine regional epithelial barrier dysfunction in animal models of gastrointestinal disease.

This protocol may be used to examine regional changes in intestinal barrier function in animal models of gastrointestinal disease. By measuring the flux of a paracellular probe across the mucosal surface at varying areas of the gastrointestinal tract7, the integrity of the epithelial tight junctions can be assessed. In addition, by varying the nature of the paracellular probe by size (Figure 2) or hydrophobicity (Figure 3), the degree of epithe...

Watch this Scientific Journal Video about Ex Vivo Intestinal Sacs to Assess Mucosal Permeability in Models of Gastrointestinal Disease at JoVE.com

Ex Vivo Intestinal Sacs to Assess Mucosal Permeability in Models of Gastrointestinal Disease

This protocol describes the use of excised intestinal tissue preparations or "intestinal sacs" as an ex vivo model of intestinal barrier function. This model may be used to assess integrity of both the epithelial barrier and the mucous gel layer at specific intestinal sites in animal models of digestive disease.

Ex Vivo Intestinal Sacs to Assess Mucosal Permeability in Models of Gastrointestinal Disease

The epithelial barrier is the first innate defense of the gastrointestinal tract and selectively regulates transport from the lumen to the underlying ...

The overall goal of this procedure is to assess the localized intestinal integrity in animal models of gastrointestinal disease.This method can help answer key quesitons about gastrointestinal disease, such as whether musosal integrity is lost or if there is an increase in uptake of a specific molecule or bacteria during disease.The main advantage of this technique is that it can be used to assess specific areas within the gastrointestinal tract.To prepare the gastrointestinal tract, begin by spraying the abdomen and thorax of the mouse with 70 percent ethanol and use scissors to make a horizontal incision in the middle of the abdomen, to expose the peritoneum.Next, cut the upper small intestine from the stomach at the pyloric sphincter and the large intestine at the anal verge.Then use forceps to gently remove the mesentery and place the intestinal tract in prewarmed, oxyginated medium.Identify the area to be assessed for permeability, measuring the sections of the duodenum and jejunum relative to the stomach in the sections of the colon and ilium relative to the cecum to maintain consistency between the experimental animals.Note the presence of mucosa associated lymphoid tissues such as Peyer's patches, which can be identified as small nodules on the sarosal side of the lumen.Then, cut the selected section and use a 1 ml syringe to gently flush the lumenal contents of the segment into a petri dish containing 37

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An in vivo Assay to Test Blood Vessel Permeability

This method is based on the intravenous injection of Evans Blue in mice as the test animal model. Evans blue is a dye that binds albumin. Under physiologic conditions the endothelium is impermeable to albumin, so Evans blue bound albumin remains restricted within blood vessels. In pathologic conditions that promote increased vascular permeability endothelial cells partially lose their close contacts and the endothelium becomes permeable to small proteins such as albumin. This condition allows for extravasation of Evans Blue in tissues. A healthy endothelium prevents extravasation of the dye in the neighboring vascularized tissues. Organs with increased permeability will show significantly increased blue coloration compared to organs with intact endothelium. The level of vascular permeability can be assessed by simple visualization or by quantitative measurement of the dye incorporated per milligram of tissue of control versus experimental animal/tissue. Two powerful aspects of this assay are its simplicity and quantitative characteristics. Evans Blue dye can be extracted from tissues by incubating a specific amount of tissue in formamide. Evans Blue absorbance maximum is at 620 nm and absorbance minimum is at 740 nm. By using a standard curve for Evans Blue, optical density measurements can be converted into milligram dye captured per milligram of tissue. Statistical analysis should be used to assess significant differences in vascular permeability.

An in vivo Assay to Test Blood Vessel Permeability

We are presenting an in vivo assay to test blood vessel permeability. This assay is based on intravenous injection of a dye and subsequent visualization of its diffusion into interstitial spaces.

This method is based on the intravenous injection of Evans Blue in mice as the test animal model. Evans blue is a dye that binds albumin. Under ...

Gene-environment Interaction Models to Unmask Susceptibility Mechanisms in Parkinson's Disease

Lipoxygenase (LOX) activity has been implicated in neurodegenerative disorders such as Alzheimer&#39;s disease, but its effects in Parkinson&#39;s disease (PD) pathogenesis are less understood. Gene-environment interaction models have utility in unmasking the impact of specific cellular pathways in toxicity that may not be observed using a solely genetic or toxicant disease model alone.&#160;To evaluate if distinct LOX isozymes selectively contribute to PD-related neurodegeneration, transgenic (i.e. 5-LOX and 12/15-LOX deficient) mice can be challenged with a toxin that mimics cell injury and death in the disorder.&#160;Here we describe the use of a neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which produces a nigrostriatal lesion to elucidate the distinct contributions of LOX isozymes to neurodegeneration related to PD. The use of MPTP in mouse, and nonhuman primate, is well-established to recapitulate the nigrostriatal damage in PD.&#160;The extent of MPTP-induced lesioning is measured by HPLC analysis of dopamine and its metabolites and semi-quantitative Western blot analysis of striatum for tyrosine hydroxylase (TH), the rate-limiting enzyme for the synthesis of dopamine. To assess inflammatory markers, which may demonstrate LOX isozyme-selective sensitivity, glial fibrillary acidic protein (GFAP) and Iba-1 immunohistochemistry are performed on brain sections containing substantia nigra, and GFAP Western blot analysis is performed on striatal homogenates.&#160;This experimental approach can provide novel insights into gene-environment interactions underlying nigrostriatal degeneration and PD.

Gene-environment Interaction Models to Unmask Susceptibility Mechanisms in Parkinson&#039;s Disease

Lipoxygenase (LOX) isozymes can generate products that may increase or decrease neuroinflammation and neurodegeneration.&#160;A gene-environment interaction study could identify LOX isozyme-specific effects. Using the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of nigrostriatal damage in two LOX isozyme-deficient transgenic lines allows for comparison of the contribution of LOX isozymes on dopaminergic integrity and inflammation.

Lipoxygenase (LOX) activity has been implicated in neurodegenerative disorders such as Alzheimer&#39;s disease, but its effects in Parkinson&#39;s disease ...

Adapting Human Videofluoroscopic Swallow Study Methods to Detect and Characterize Dysphagia in Murine Disease Models

This study adapted human videofluoroscopic swallowing study (VFSS) methods for use with murine disease models for the purpose of facilitating translational dysphagia research. Successful outcomes are dependent upon three critical components: test chambers that permit self-feeding while standing unrestrained in a confined space, recipes that mask the aversive taste/odor of commercially-available oral contrast agents, and a step-by-step test protocol that permits quantification of swallow physiology. Elimination of one or more of these components will have a detrimental impact on the study results. Moreover, the energy level capability of the fluoroscopy system will determine which swallow parameters can be investigated. Most research centers have high energy fluoroscopes designed for use with people and larger animals, which results in exceptionally poor image quality when testing mice and other small rodents. Despite this limitation, we have identified seven VFSS parameters that are consistently quantifiable in mice when using a high energy fluoroscope in combination with the new murine VFSS protocol. We recently obtained a low energy fluoroscopy system with exceptionally high imaging resolution and magnification capabilities that was designed for use with mice and other small rodents. Preliminary work using this new system, in combination with the new murine VFSS protocol, has identified 13 swallow parameters that are consistently quantifiable in mice, which is nearly double the number obtained using conventional (i.e., high energy) fluoroscopes. Identification of additional swallow parameters is expected as we optimize the capabilities of this new system. Results thus far demonstrate the utility of using a low energy fluoroscopy system to detect and quantify subtle changes in swallow physiology that may otherwise be overlooked when using high energy fluoroscopes to investigate murine disease models.

This study successfully adapted human videofluoroscopic swallowing study (VFSS) methods for use with murine disease models for the purpose of facilitating translational dysphagia research.

This study adapted human videofluoroscopic swallowing study (VFSS) methods for use with murine disease models for the purpose of facilitating ...

An Ex vivo Model to Study Hormone Action in the Human Breast

The study of hormone action in the human breast has been hampered by lack of adequate model systems. Upon in vitro culture, primary mammary epithelial cells tend to lose hormone receptor expression. Widely used hormone receptor positive breast cancer cell lines are of limited relevance to the in vivo situation. Here, we describe an ex vivo model to study hormone action in the human breast. Fresh human breast tissue specimens from surgical discard material such as reduction mammoplasties or mammectomies are mechanically and enzymatically digested to obtain tissue fragments containing ducts and lobules and multiple stromal cell types. These tissue microstructures kept in basal medium without growth factors preserve their intercellular contacts, the tissue architecture, and remain hormone responsive for several days. They are readily processed for RNA and protein extraction, histological analysis or stored in freezing medium. Fluorescence activated cell sorting (FACS) can be used to enrich for specific cell populations. This protocol provides a straightforward, standard approach for translational studies with highly complex, varied human specimens.

An Ex vivo Model to Study Hormone Action in the Human Breast

We have developed a novel ex vivo model to study hormone action in the human breast. It is based on tissue microstructures isolated from surgical breast tissue specimens which preserve tissue architecture, intercellular interactions, and paracrine signaling.

The study of hormone action in the human breast has been hampered by lack of adequate model systems. Upon in vitro culture, primary mammary epithelial ...

In Vivo and Ex Vivo Approaches to Study Ovarian Cancer Metastatic Colonization of Milky Spot Structures in Peritoneal Adipose

High-grade serous ovarian cancer (HGSC), the cause of widespread peritoneal metastases, continues to have an extremely poor prognosis; fewer than 30% of women are alive 5 years after diagnosis. The omentum is a preferred site of HGSC metastasis formation. Despite the clinical importance of this microenvironment, the contribution of omental adipose tissue to ovarian cancer progression remains understudied. Omental adipose is unusual in that it contains structures known as milky spots, which are comprised of B, T, and NK cells, macrophages, and progenitor cells surrounding dense nests of vasculature. Milky spots play a key role in the physiologic functions of the omentum, which are required for peritoneal homeostasis. We have shown that milky spots also promote ovarian cancer metastatic colonization of peritoneal adipose, a key step in the development of peritoneal metastases. Here we describe the approaches we developed to evaluate and quantify milky spots in peritoneal adipose and study their functional contribution to ovarian cancer cell metastatic colonization of omental tissues both in vivo and ex vivo. These approaches are generalizable to additional mouse models and cell lines, thus enabling the study of ovarian cancer metastasis formation from initial localization of cells to milky spot structures to the development of widespread peritoneal metastases.

In Vivo and Ex Vivo Approaches to Study Ovarian Cancer Metastatic Colonization of Milky Spot Structures in Peritoneal Adipose

We outline a protocol that implements both in vivo and ex vivo approaches to study ovarian cancer colonization of peritoneal adipose tissues, particularly the omentum. Furthermore, we present a protocol to quantitate and analyze immune cell-structures in the omentum known as milky spots, which promote metastases of peritoneal adipose.

High-grade serous ovarian cancer (HGSC), the cause of widespread peritoneal metastases, continues to have an extremely poor prognosis; fewer than 30% of ...

Use of Ultra-high Field MRI in Small Rodent Models of Polycystic Kidney Disease for In Vivo Phenotyping and Drug Monitoring

Several in vivo pre-clinical studies in Polycystic Kidney Disease (PKD) utilize orthologous rodent models to identify and study the genetic and molecular mechanisms responsible for the disease, and are very convenient for rapid drug screening and testing of promising therapies. A limiting factor in these studies is often the lack of efficient non-invasive methods for sequentially analyzing the anatomical and functional changes in the kidney. Magnetic resonance imaging (MRI) is the current gold standard imaging technique to follow autosomal dominant polycystic kidney disease (ADPKD) patients, providing excellent soft tissue contrast and anatomic detail and allowing Total Kidney Volume (TKV) measurements.A major advantage of MRI in rodent models of PKD is the possibility for in vivo imaging allowing for longitudinal studies that use the same animal and therefore reducing the total number of animals required. In this manuscript, we will focus on using Ultra-high field (UHF) MRI to non-invasively acquire in vivo images of rodent models for PKD. The main goal of this work is to introduce the use of MRI as a tool for in vivo phenotypical characterization and drug monitoring in rodent models for PKD.

Use of Ultra-high Field MRI in Small Rodent Models of Polycystic Kidney Disease for In Vivo Phenotyping and Drug Monitoring

The use of ultra-high field MRI as a non-invasive way to obtain phenotypic information of rodent models for polycystic kidney disease and to monitor interventions is described. Compared with the traditional histological approach, MRI images can be acquired in vivo, allowing for longitudinal follow-up.

Several in vivo pre-clinical studies in Polycystic Kidney Disease (PKD) utilize orthologous rodent models to identify and study the genetic and molecular ...

Using an Ingestible Telemetric Temperature Pill to Assess Gastrointestinal Temperature During Exercise

Exercise results in an increase in core body temperature (Tc), which may reduce exercise performance and eventually can lead to the development of heat-related disorders. Therefore, accurate measurement of Tc during exercise is of great importance, especially in athletes who have to perform in challenging ambient conditions. In the current literature a number of methods have been described to measure the Tc (esophageal, external tympanic membrane, mouth or rectum). However, these methods are suboptimal to measure Tc during exercise since they are invasive, have a slow response or are influenced by environmental conditions. Studies described the use of an ingestible telemetric temperature pill as a reliable and valid method to assess gastrointestinal temperature (Tgi), which is a representative measurement of Tc. Therefore, the goal of this study was to provide a detailed description of the measurement of Tgi using an ingestible telemetric temperature pill. This study addresses important methodological factors that must be taken into account for an accurate measurement. It is recommended to read the instructions carefully in order to ensure that the ingestible telemetric temperature pill is a reliable method to assess Tgi at rest and during exercise.

This study describes an accurate, reliable and non-invasive technique to continuously measure gastrointestinal temperature during exercise. The ingestible telemetric temperature pill is suitable to measure gastrointestinal temperature in laboratory settings as well as in field based settings.

Exercise results in an increase in core body temperature (Tc), which may reduce exercise performance and eventually can lead to the development of ...

Depletion of Mouse Cells from Human Tumor Xenografts Significantly Improves Downstream Analysis of Target Cells

The use of in vitro cell line models for cancer research has been a useful tool. However, it has been shown that these models fail to reliably mimic patient tumors in different assays1. Human tumor xenografts represent the gold standard with respect to tumor biology, drug discovery, and metastasis research 2-4. Tumor xenografts can be derived from different types of material like tumor cell lines, tumor tissue from primary patient tumors4 or serially transplanted tumors. When propagated in vivo, xenografted tissue is infiltrated and vascularized by cells of mouse origin. Multiple factors such as the tumor entity, the origin of xenografted material, growth rate and region of transplantation influence the composition and the amount of mouse cells present in tumor xenografts. However, even when these factors are kept constant, the degree of mouse cell contamination is highly variable.
Contaminating mouse cells significantly impair downstream analyses of human tumor xenografts. As mouse fibroblasts show high plating efficacies and proliferation rates, they tend to overgrow cultures of human tumor cells, especially slowly proliferating subpopulations. Mouse cell derived DNA, mRNA, and protein components can bias downstream gene expression analysis, next-generation sequencing, as well as proteome analysis 5. To overcome these limitations, we have developed a fast and easy method to isolate untouched human tumor cells from xenografted tumor tissue. This procedure is based on the comprehensive depletion of cells of mouse origin by combining automated tissue dissociation with the benchtop tissue dissociator and magnetic cell sorting. Here, we demonstrate that human target cells can be can be obtained with purities higher than 96% within less than 20 min independent of the tumor type.

Human tumor xenografts are vascularized and infiltrated by cells of mouse origin during the growth phase in vivo. To circumvent the bias caused by these contaminating cells during downstream analysis, we developed a method allowing for comprehensive depletion of all mouse cells by magnetic cell sorting.

The use of in vitro cell line models for cancer research has been a useful tool. However, it has been shown that these models fail to reliably mimic ...

Assessment of Kidney Function in Mouse Models of Glomerular Disease

The use of murine models to mimic human kidney disease is becoming increasingly common. Our research is focused on the assessment of glomerular function in diabetic nephropathy and podocyte-specific VEGF-A knock-out mice; therefore, this protocol describes the full kidney work-up used in our lab to assess these mouse models of glomerular disease, enabling a vast amount of information regarding kidney and glomerular function to be obtained from a single mouse. In comparison to alternative methods presented in the literature to assess glomerular function, the use of the method outlined in this paper enables the glomerular phenotype to be fully evaluated from multiple aspects. By using this method, the researcher can determine the kidney phenotype of the model and assess the mechanism as to why the phenotype develops. This vital information on the mechanism of disease is required when examining potential therapeutic avenues in these models. The methods allow for detailed functional assessment of the glomerular filtration barrier through measurement of the urinary albumin creatinine ratio and individual glomerular water permeability, as well as both structural and ultra-structural examination using the Periodic Acid Schiff stain and electron microscopy. Furthermore, analysis of the genes dysregulated at the mRNA and protein level enables mechanistic analysis of glomerular function. This protocol outlines the generic but adaptable methods that can be applied to all mouse models of glomerular disease.

This protocol describes a full kidney work-up that should be carried out in mouse models of glomerular disease. The methods allow for detailed functional, structural, and mechanistic analysis of glomerular function, which can be applied to all mouse models of glomerular disease.

The use of murine models to mimic human kidney disease is becoming increasingly common. Our research is focused on the assessment of glomerular function ...

In Vivo Photolabeling of Cells in the Colon to Assess Migratory Potential of Hematopoietic Cells in Neonatal Mice

Enteric bacterial communities are established early in life and influence immune cell development and function. The neonatal microbiota is susceptible to numerous external influences including antibiotics use and diet, which impacts susceptibility to autoimmune and inflammatory diseases. Disorders such as Inflammatory Bowel Disease (IBD) are characterized by a massive influx of immune cells to the intestines. However, immune cells conditioned by the microbiota may additionally emigrate out of the intestines to influence immune responses at extra-intestinal sites. Thus, there is a need to identify and characterize cells that may carry microbial messages from the intestines to distal sites. Here, we describe a method to label cells in the colon of newborn mice in vivo that enables their identification at extra-intestinal sites after migration.

In Vivo Photolabeling of Cells in the Colon to Assess Migratory Potential of Hematopoietic Cells in Neonatal Mice

The protocol described here utilizes a photolabeling approach in newborn mice to specifically identify immune cells that emigrate from the colon to extra-intestinal sites. This strategy will be useful to study host-microbiome interactions in early life.

Enteric bacterial communities are established early in life and influence immune cell development and function. The neonatal microbiota is susceptible to ...