Name: 3-dimensional resin casting and imaging of mouse portal vein or intrahepatic bile duct system
Uploaded: 2012-10-25T13:00:00
Description: Watch this Scientific Journal Video about 3-Dimensional Resin Casting and Imaging of Mouse Portal Vein or Intrahepatic Bile Duct System at JoVE.com

This work was supported by grants from the National Institutes of Health (NIH) to S.S.H. (R01-DK078640), from the Howard Hughes Medical Institute (HHMI) through the HHMI/Vanderbilt University Certificate Program in Molecular Medicine to T.J.W. (GRDOT56006779), the Vanderbilt Diabetes Research and Training Center (P30-DK020593) and the Vanderbilt Digestive Disease Research Center (P30-DK058404) providing Core Services.

1. Prepare Cannula
<ol>
 <li>Warm a 1-inch long section of PE10 tubing with your fingertips and stretch it so that the tubing becomes thin. 
 Note: the size of the vessel or duct to be cannulated will determine the degree of stretching required. The cannula must be well-stretched for bile duct casts but may only be required to be moderately stretched to fit within the larger portal vein.</li>
 <li>Cut the stretched tubing at a diagonal to generate a beveled tip.</li>
 <li>Cut the other edge of the tubing ...

<ol>
	<li>Sparks, E. E., Perrien, D. S., Huppert, K. A., Peterson, T. E., Huppert, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Defects+in+hepatic+Notch+signaling+result+in+disruption+of+the+communicating+intrahepatic+bile+duct+network+in+mice.">Defects in hepatic Notch signaling result in disruption of the communicating intrahepatic bile duct network in mice.</a> Dis. Model Mech. 4, 359-367 (2011).</li><li>Vanderpool, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+interactions+between+hepatocyte+nuclear+factor-6+and+notch+signaling+regulate+mouse+intrahepatic+bile+duct+development+in+vivo.">Genetic interactions between hepatocyte nuclear factor-6 and notch signaling regulate mouse intrahepatic bile duct development in vivo.</a> Hepatology. 55, 233-243 (2012).</li><li>Meyer, E. P., Ulmann-Schuler, A., Staufenbiel, M., Krucker, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Altered+morphology+and+3D+architecture+of+brain+vasculature+in+a+mouse+model+for+Alzheimer's+disease.">Altered morphology and 3D architecture of brain vasculature in a mouse model for Alzheimer's disease.</a> Proceedings of the National Academy of Sciences. 105, 3587-3592 (2008).</li><li>Van Steenkiste, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vascular+corrosion+casting:+analyzing+wall+shear+stress+in+the+portal+vein+and+vascular+abnormalities+in+portal+hypertensive+and+cirrhotic+rodents.">Vascular corrosion casting: analyzing wall shear stress in the portal vein and vascular abnormalities in portal hypertensive and cirrhotic rodents.</a> Lab Invest. 90, 1558-1572 (2010).</li><li>Dickie, R., Cormack, M., Semmler-Behnke, M., Kreyling, W. 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S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Notch+signaling+regulates+formation+of+the+three-dimensional+architecture+of+intrahepatic+bile+ducts+in+mice.">Notch signaling regulates formation of the three-dimensional architecture of intrahepatic bile ducts in mice.</a> Hepatology. 51, 1391-1400 (2010).</li><li>Carlson, T. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelial+expression+of+constitutively+active+Notch4+elicits+reversible+arteriovenous+malformations+in+adult+mice.">Endothelial expression of constitutively active Notch4 elicits reversible arteriovenous malformations in adult mice.</a> Proc. Natl. Acad. Sci. U.S.A. 102, 9884-9889 (2005).</li><li>Hemmeryckx, B., Emmerechts, J., Bovill, E. G., Hoylaerts, M. F., Lijnen, H. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+ageing+on+the+murine+venous+circulation.">Effect of ageing on the murine venous circulation.</a> Histochem. Cell Biol. , (2012).</li><li>Hossler, F. E., Olson, K. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microvasculature+of+the+nasal+salt+gland+of+the+duckling,+Anas+platyrhynchos:+quantitative+responses+to+osmotic+adaptation+and+deadaptation+studied+with+vascular+corrosion+casting.">Microvasculature of the nasal salt gland of the duckling, Anas platyrhynchos: quantitative responses to osmotic adaptation and deadaptation studied with vascular corrosion casting.</a> J. Exp. Zool. 254, 237-247 (1990).</li><li>Hossler, F. E., West, R. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Venous+valve+anatomy+and+morphometry:+studies+on+the+duckling+using+vascular+corrosion+casting.">Venous valve anatomy and morphometry: studies on the duckling using vascular corrosion casting.</a> Am. J. Anat. 181, 425-432 (1988).</li><li>Hossler, F. E., Monson, F. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure+and+blood+supply+of+intrinsic+lymph+nodes+in+the+wall+of+the+rabbit+urinary+bladder--studies+with+light+microscopy,+electron+microscopy,+and+vascular+corrosion+casting.">Structure and blood supply of intrinsic lymph nodes in the wall of the rabbit urinary bladder--studies with light microscopy, electron microscopy, and vascular corrosion casting.</a> Anat. Rec. 252, 477-484 (1998).</li><li>Hossler, F. E., Monson, F. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+for+a+unique+elastic+sheath+surrounding+the+vesicular+arteries+of+the+rabbit+urinary+bladder--studies+of+the+microvasculature+with+microscopy+and+vascular+corrosion+casting.">Evidence for a unique elastic sheath surrounding the vesicular arteries of the rabbit urinary bladder--studies of the microvasculature with microscopy and vascular corrosion casting.</a> Anat. Rec. 252, 472-476 (1998).</li><li>Hossler, F. E., Kao, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microvasculature+of+the+urinary+bladder+of+the+dog:+a+study+using+vascular+corrosion+casting.">Microvasculature of the urinary bladder of the dog: a study using vascular corrosion casting.</a> Microsc. Microanal. 13, 220-227 (2007).</li><li>Wischgoll, T., Choy, J. S., Kassab, G. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extraction+of+morphometry+and+branching+angles+of+porcine+coronary+arterial+tree+from+CT+images.">Extraction of morphometry and branching angles of porcine coronary arterial tree from CT images.</a> Am J Physiol. Heart. Circ. Physiol. 297, H1949-H1955 (2009).</li><li>Hossler, F. E., Douglas, J. E., Douglas, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anatomy+and+morphometry+of+myocardial+capillaries+studied+with+vascular+corrosion+casting+and+scanning+electron+microscopy:+a+method+for+rat+heart.">Anatomy and morphometry of myocardial capillaries studied with vascular corrosion casting and scanning electron microscopy: a method for rat heart.</a> Scan Electron Microsc. , 1469-1475 (1986).</li><li>Hossler, F. E., Douglas, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vascular+Corrosion+Casting:+Review+of+Advantages+and+Limitations+in+the+Application+of+Some+Simple+Quantitative+Methods.">Vascular Corrosion Casting: Review of Advantages and Limitations in the Application of Some Simple Quantitative Methods.</a> Microsc. Microanal. 7, 253-264 (2001).</li><li>Mondy, W. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Micro-CT+of+corrosion+casts+for+use+in+the+computer-aided+design+of+microvasculature.">Micro-CT of corrosion casts for use in the computer-aided design of microvasculature.</a> Tissue Eng. Part C Methods. 15, 729-738 (2009).</li><li>Masyuk, T. V., Ritman, E. L., LaRusso, N. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+Assessment+of+the+Rat+Intrahepatic+Biliary+System+by+Three-Dimensional+Reconstruction.">Quantitative Assessment of the Rat Intrahepatic Biliary System by Three-Dimensional Reconstruction.</a> The American Journal of Pathology. 158, 2079-2088 (2001).</li><li>Masyuk, T. V., Ritman, E. L., LaRusso, N. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hepatic+Artery+and+Portal+Vein+Remodeling+in+Rat+Liver:+Vascular+Response+to+Selective+Cholangiocyte+Proliferation.">Hepatic Artery and Portal Vein Remodeling in Rat Liver: Vascular Response to Selective Cholangiocyte Proliferation.</a> The American Journal of Pathology. 162, 1175-1182 (2003).</li></ol>

We have described specific examples for how the portal vein and intrahepatic bile duct systems of the liver can be cast, but this technique can be applied to virtually any other ductal or vascular system with slight adaptations. Previous work has demonstrated the feasibility of this technique in multiple species, including mouse1,2,7-9, duckling10,11, rabbit12,13, dog14, and pig15, and in many organs, including nasal gland14, heart16, bladder<su...

<table border="1">
 <tbody>
 <tr>
 <td>Name of reagent</td>
 <td>Company</td>
 <td>Catalog number</td>
 <td>Comments</td>
 </tr>
 <tr>
 <td>PE10 polyethylene tubing</td>
 <td>Fisher Scientific</td>
 <td>1417012P</td>
 <td></td>
 </tr>
 <tr>
 <td>5-0 surgical black braided silk</td>
 <td>Roboz Surgical</td>
 <td>SUT-15-1</td>
 <td></td>
 </tr>
 <tr>
 <td>Steriject 32 G x 13 mm needle</td>
 <td>Air-tite</td>
 <td>TSK3213</td>
 <td></td>
 </tr>
 <tr>
 <td>Spring scissors</td>
 <td>Fine Science Tools</td>
 <td>15000-08</td>
 <td></td>
 </tr>
 <tr>
 <td>Number 5 forceps</td>
 <td>Fine Science Tools</td>
 <td>91150-20</td>
 <td></td>
 </tr>
 <tr>
 <td>Mercox II kit</td>
 <td>Ladd Research</td>
 <td>21247</td>
 <td></td>
 </tr>
 <tr>
 <td>Benzyl alcohol</td>
 <td>Fisher Scientific</td>
 <td>1816-04</td>
 <td>Only required for BABB-clearing</td>
 </tr>
 <tr>
 <td>Benzyl benzoate</td>
 <td>MP Biomedicals, LLC</td>
 <td>154839</td>
 <td>Only required for BABB-clearing</td>
 </tr>
 <tr>
 <td>Phosphate-buffered saline (PBS)</td>
 <td></td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>Modeling clay</td>
 <td></td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>Scale</td>
 <td></td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>Laboratory scissors</td>
 <td></td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>15 ml cap polypropylene tubes</td>
 <td></td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>4% paraformaldahyde</td>
 <td></td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>15% potassium hydroxide (KOH)</td>
 <td></td>
 <td></td>
 <td>Only required for maceration</td>
 </tr>
 <tr>
 <td>Razor blade</td>
 <td></td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>100% methanol</td>
 <td></td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>3 ml luer lock syringe</td>
 <td></td>
 <td></td>
 <td></td>
 </tr>
 </tbody>
</table>

3-dimensional resin casting and imaging of mouse portal vein or intrahepatic bile duct system

In organs, the correct architecture of vascular and ductal structures is indispensable for proper physiological function, and the formation and maintenance of these structures is a highly regulated process. The analysis of these complex, 3-dimensional structures has greatly depended on either 2-dimensional examination in section or on dye injection studies. These techniques, however, are not able to provide a complete and quantifiable representation of the ductal or vascular structures they are intended to elucidate. Alternatively, the nature of 3-dimensional plastic resin casts generates a permanent snapshot of the system and is a novel and widely useful technique for visualizing and quantifying 3-dimensional structures and networks.
A crucial advantage of the resin casting system is the ability to determine the intact and connected, or communicating, structure of a blood vessel or duct. The structure of vascular and ductal networks are crucial for organ function, and this technique has the potential to aid study of vascular and ductal networks in several ways. Resin casting may be used to analyze normal morphology and functional architecture of a luminal structure, identify developmental morphogenetic changes, and uncover morphological differences in tissue architecture between normal and disease states. Previous work has utilized resin casting to study, for example, architectural and functional defects within the mouse intrahepatic bile duct system that were not reflected in 2-dimensional analysis of the structure1,2, alterations in brain vasculature of a Alzheimer's disease mouse model3, portal vein abnormalities in portal hypertensive and cirrhotic mice4, developmental steps in rat lymphatic maturation between immature and adult lungs5, immediate microvascular changes in the rat liver, pancreas, and kidney in response in to chemical injury6.
Here we present a method of generating a 3-dimensional resin cast of a mouse vascular or ductal network, focusing specifically on the portal vein and intrahepatic bile duct. These casts can be visualized by clearing or macerating the tissue and can then be analyzed. This technique can be applied to virtually any vascular or ductal system and would be directly applicable to any study inquiring into the development, function, maintenance, or injury of a 3-dimensional ductal or vascular structure.

Watch this Scientific Journal Video about 3-Dimensional Resin Casting and Imaging of Mouse Portal Vein or Intrahepatic Bile Duct System at JoVE.com

3-Dimensional Resin Casting and Imaging of Mouse Portal Vein or Intrahepatic Bile Duct System

A method of visualizing and quantifying the 3-dimensional structure of mouse hepatic portal vein or intrahepatic bile duct is described. This resin cast technique can also be applied to other ductal or vascular systems and allows for in situ visualization or quantification of a system's intact communicating architecture.

In  organs, the correct architecture of vascular and ductal structures is  indispensable for proper physiological function, and the formation and  ...

3-dimensional-resin-casting-imaging-mouse-portal-vein-or-intrahepatic

Research

JoVE Journal

Medicine

Modeling and Imaging 3-Dimensional Collective Cell Invasion

A defining characteristic of cancer malignancy is invasion and metastasis 1. In some cancers (e.g. glioma 2), local invasion into surrounding healthy tissue is the root cause of disease and death. For other cancers (e.g. breast, lung, etc.), it is the process of metastasis, in which tumor cells move from a primary tumor mass, colonize distal sites and ultimately contribute to organ failure, that eventually leads to morbidity and mortality 3. It has been estimated that invasion and metastasis are responsible for 90&#37; of cancer deaths 4. As a result, there has been intense interest in identifying the molecular processes and critical protein mediators of invasion and metastasis for the purposes of improving diagnosis and treatment 5.
A challenge for cancer scientists is to develop invasion assays that sufficiently resemble the in vivo situation to enable accurate disease modeling 6. Two-dimensional cell motility assays are only informative about one aspect of invasion and do not take into account extracellular matrix (ECM) protein remodeling which is also a critical element. Recently, research has refined our understanding of tumor cell invasion and revealed that individual cells may move by elongated or rounded modes 7. In addition, there has been greater appreciation of the contribution of collective invasion, in which cells invade in strands, sheets and clusters, particularly in highly differentiated tumors that maintain epithelial characteristics, to the spread of cancer 8.
We present a refined method 9 for examining the contributions of candidate proteins to collective invasion 10. In particular, by engineering separate pools of cells to express different fluorescent proteins, it is possible to molecularly dissect the activities and proteins required in leading cells versus those required in following cells. The use of RNAi provides the molecular tool to experimentally disassemble the processes involved in individual cell invasion as well as in different positions of collective invasion. In this procedure, mixtures of fluorescently-labeled cells are plated on the bottom of a Transwell insert previously filled with Matrigel ECM protein, then allowed to invade "upwards" through the filter and into the Matrigel. Reconstruction of z-series image stacks, obtained by confocal imaging, into three-dimensional representations allows for visualization of collectively invading strands and analysis of the representation of fluorescently-labeled cells in leading versus following positions.

Models of tumor cell invasion into three-dimensional extracellular matrix better reflect the in vivo situation than two-dimensional motility assays. Using matrix invasion assays combined with confocal imaging of fluorescently-labeled cells, detailed information on invasion modes and the distinct contributions of leading versus following cells can be obtained.

A defining characteristic of cancer malignancy is invasion and metastasis 1. In some cancers (e.g. glioma 2), local invasion into surrounding healthy ...

Bile Duct Ligation in Mice: Induction of Inflammatory Liver Injury and Fibrosis by Obstructive Cholestasis

In most vertebrates, the liver produces bile that is necessary to emulsify absorbed fats and enable the digestion of lipids in the small intestine as well as to excrete bilirubin and other metabolic products. In the liver, the experimental obstruction of the extrahepatic biliary system initiates a complex cascade of pathological events that leads to cholestasis and inflammation resulting in a strong fibrotic reaction originating from the periportal fields. Therefore, surgical ligation of the common bile duct has become the most commonly used model to induce obstructive cholestatic injury in rodents and to study the molecular and cellular events that underlie these pathophysiological mechanisms induced by inappropriate bile flow. In recent years, different surgical techniques have been described that either allow reconnection or reanastomosis after bile duct ligation (BDL), e.g., partial BDL, or other microsurgical methods for specific research questions. However, the most frequently used model is the complete obstruction of the common bile duct that induces a strong fibrotic response after 21 to 28 days. The mortality rate can be high due to infectious complications or technical inaccuracies. Here we provide a detailed surgical procedure for the BDL model in mice that induce a highly reproducible fibrotic response in accordance to the 3R rule for animal welfare postulated by Russel and Burch in 1959.

Disruption of bile flow results in severe inflammatory cholestatic liver injury with a characteristic time-dependent sequence of morphological alterations. Here we present a protocol for the surgical ligation of the common bile duct in mice that allows to induce a strong fibrotic response after 21 to 28 days.

In most vertebrates, the liver produces bile that is necessary to emulsify absorbed fats and enable the digestion of lipids in the small intestine as well ...

Using Multi-fluorinated Bile Acids and In Vivo Magnetic Resonance Imaging to Measure Bile Acid Transport

Along with their traditional role as detergents that facilitate fat absorption, emerging literature indicates that bile acids are potent signaling molecules that affect multiple organs; they modulate gut motility and hormone production, and alter vascular tone, glucose metabolism, lipid metabolism, and energy utilization. Changes in fecal bile acids may alter the gut microbiome and promote colon pathology including cholerrheic diarrhea and colon cancer. Key regulators of fecal bile acid composition are the small intestinal Apical Sodium-dependent Bile Acid Transporter (ASBT) and fibroblast growth factor-19 (FGF19). Reduced expression and function of ASBT decreases intestinal bile acid up-take. Moreover, in vitro data suggest that some FDA-approved drugs inhibit ASBT function. Deficient FGF19 release increases hepatic bile acid synthesis and release into the intestines to levels that overwhelm ASBT. Either ASBT dysfunction or FGF19 deficiency increases fecal bile acids and may cause chronic diarrhea and promote colon neoplasia. Regrettably, tools to measure bile acid malabsorption and the actions of drugs on bile acid transport in vivo are limited. To understand the complex actions of bile acids, techniques are required that permit simultaneous monitoring of bile acids in the gut and metabolic tissues. This led us to conceive an innovative method to measure bile acid transport in live animals using a combination of proton (1H) and fluorine (19F) magnetic resonance imaging (MRI). Novel tracers for fluorine (19F)-based live animal MRI were created and tested, both in vitro and in vivo. Strengths of this approach include the lack of exposure to ionizing radiation and translational potential for clinical research and practice.

Using Multi-fluorinated Bile Acids and In Vivo Magnetic Resonance Imaging to Measure Bile Acid Transport

Tools to diagnose bile acid malabsorption and measure bile acid transport in vivo are limited. An innovative approach in live animals is described that utilizes combined proton (1H) plus fluorine (19F) magnetic resonance imaging; this novel methodology has translational potential to screen for bile acid malabsorption in clinical practice.

Along with their traditional role as detergents that facilitate fat absorption, emerging literature indicates that bile acids are potent signaling ...

Ileectomy-induced Bile Overaccumulation in Mouse Intestine

Intestinal resection is a common therapeutic approach for human diseases such as obesity, inflammatory bowel disease, Crohn's disease, and colon cancer that often results in severe short bowel syndrome-like adverse effects including bile acid diarrhea, dehydration, electrolyte disturbances, and nutrient malabsorption. Here we introduce a murine ileal resection model, termed ileectomy, to evaluate tissue communication and the maintenance of systemic homeostasis. After ileal resection, circulating blood is permanently devoid of the ileum-specific endocrine hormone fibroblast growth factor 15 (FGF15), which releases its endocrinal inhibition of bile acid synthesis in the liver. In combination with the increased production and abolished reabsorption of bile acids after removing the ileum, mice that underwent surgery suffer from bile salt overaccumulation in the intestine and associated diarrhea, morbidity, and mortality. Novel usage of the surgery model introduced in this study may provide mechanistic and functional insights into ileal control of systemic metabolic regulation in physiology and disease.

Small intestine-dependent bile acid reabsorption and feedback inhibition of hepatic bile acid synthesis is important for systemic homeostasis and health. In this study, we describe a mouse model for ileal resection to evaluate ileectomy-induced bile malabsorption, overaccumulation, and toxicity in mouse intestine.

Intestinal resection is a common therapeutic approach for human diseases such as obesity, inflammatory bowel disease, Crohn's disease, and colon cancer ...

Ablation of Ischemic Ventricular Tachycardia Using a Multipolar Catheter and 3-dimensional Mapping System for High-density Electro-anatomical Reconstruction

Ventricular tachycardia (VT) in patients with ischemic cardiomyopathy mainly results from endocardial scars after myocardial infarction; those scars represent zones of slow conduction that allow the occurrence and maintenance of reentrant circuits. Catheter ablation enables substrate modification of those low voltage areas and thus can help to alter the scar tissue in such a way that arrhythmias cannot appear anymore. Hospitalizations of concerned patients decrease, quality of life and outcome rise. Consequently, VT ablation represents a growing field in electrophysiology, especially for patients with endocardial scars in ischemic heart disease after myocardial infarction. However, ablation of ventricular tachycardia remains one of the most challenging procedures in the electrophysiology lab. Precise scar definition and localization of abnormal potentials are critical for ablation success. The following manuscript describes the use of a multipolar mapping catheter and 3-dimensional (3D) mapping system to create a high density electro-anatomical map of the left ventricle including a precise scar representation as well as mapping of fractionated and late potentials in order to allow a highly accurate substrate modification.

With the following protocol, we provide an approach to Ventricular Tachycardia (VT) ablation using high density mapping with a multipolar catheter and 3D mapping system enhancing the success of the procedure.

Ventricular tachycardia (VT) in patients with ischemic cardiomyopathy mainly results from endocardial scars after myocardial infarction; those scars ...

Laser Doppler Perfusion Imaging in the Mouse Hindlimb

Blood flow recovery is a critical outcome measure after experimental hindlimb ischemia or ischemia-reperfusion. Laser Doppler perfusion imaging (LDPI) is a common, noninvasive, repeatable method for assessing blood flow recovery. The technique calculates overall blood flow in the sampled tissue from the Doppler shift in frequency caused when a laser hits moving red blood cells. Measurements are expressed in arbitrary perfusion units, so the contralateral non-intervened upon leg is usually used to help control measurements. Measurement depth is in the range of 0.3-1 mm; for hindlimb ischemia, this means that dermal perfusion is assessed. Dermal perfusion is dependent on several factors&#8212;most importantly skin temperature and anesthetic agent, which must be carefully controlled to result in reliable readings. Furthermore, hair and skin pigmentation can alter the ability of the laser to either reach or penetrate to the dermis. This article demonstrates the technique of LDPI in the mouse hindlimb.

Here, we present a protocol that demonstrates the technique and necessary controls for Laser Doppler perfusion imaging to measure blood flow in the mouse hindlimb.

Blood flow recovery is a critical outcome measure after experimental hindlimb ischemia or ischemia-reperfusion. Laser Doppler perfusion imaging (LDPI) is ...

A Mouse Model for Chronic Pancreatitis via Bile Duct TNBS Infusion

Chronic pancreatitis (CP) is a complex disease involving pancreatic inflammation and fibrosis, glandular atrophy, abdominal pain and other symptoms. Several rodent models have been developed to study CP, of which the bile duct 2,4,6 -trinitrobenzene sulfonic acid (TNBS) infusion model replicates the features of neuropathic pain seen in CP. However, bile duct drug infusion in mice is technically challenging. This protocol demonstrates the procedure of bile duct TNBS infusion for generation of a CP mouse model. TNBS was infused into the pancreas through the ampulla of Vater in the duodenum. This protocol optimized drug volume, surgical techniques, and drug handling during the procedure. TNBS-treated mice showed features of CP as reflected by bodyweight and pancreas weight reductions, changes in pain-associated behaviors, and abnormal pancreatic morphology. With these improvements, mortality associated with TNBS injection was minimal. This procedure is not only critical in generating pancreatic disease models but is also useful in local pancreatic drug delivery.

Chronic pancreatitis (CP) is a disease characterized by inflammation and fibrosis of the pancreas, often associated with intractable abdominal pain. This article focuses on refining the technique to generate a mouse model of CP via bile duct infusion with 2,4,6 -trinitrobenzene sulfonic acid (TNBS).

Chronic pancreatitis (CP) is a complex disease involving pancreatic inflammation and fibrosis, glandular atrophy, abdominal pain and other symptoms. ...

Minimizing Post-Infusion Portal Vein Bleeding during Intrahepatic Islet Transplantation in Mice

Although the liver is currently accepted as the primary transplantation site for human islets in clinical settings, islets are transplanted under the kidney capsule in most rodent preclinical islet transplantation studies. This model is commonly used because murine intrahepatic islet transplantation is technically challenging, and a high percentage of mice could die from surgical complications, especially bleeding from the injection site post-transplantation. In this study, two procedures that can minimize the incidence of post-infusion portal vein bleeding are demonstrated. The first method applies an absorbable hemostatic gelatin sponge to the injection site, and the second method involves penetrating the islet injection needle through the fat tissue first and then into the portal vein by using the fat tissue as a physical barrier to stop bleeding. Both methods could effectively prevent bleeding-induced mouse death. The whole liver section showing islet distribution and evidence of islet thrombosis post-transplantation, a typical feature for intrahepatic islet transplantation, were presented. These improved protocols refine the intrahepatic islet transplantation procedures and may help laboratories set up the procedure to study islet survival and function in pre-clinical settings.

Here we present refined surgical procedures on successfully performing intraportal islet transplantation, a clinically relevant but technically challenging surgical procedure, in mice.

Although the liver is currently accepted as the primary transplantation site for human islets in clinical settings, islets are transplanted under the ...

DUCT: Double Resin Casting followed by Micro-Computed Tomography for 3D Liver Analysis

The liver is the biggest internal organ in humans and mice, and high auto-fluorescence presents a significant challenge for assessing the three-dimensional (3D) architecture of the organ at the whole-organ level. Liver architecture is characterized by multiple branching lumenized structures, which can be filled with resin, including vascular and biliary trees, establishing a highly stereotyped pattern in the otherwise hepatocyte-rich parenchyma. This protocol describes the pipeline for performing double resin casting micro-computed tomography, or &#34;DUCT&#34;. DUCT entails injecting the portal vein and common bile duct with two different radiopaque synthetic resins, followed by tissue fixation. Quality control by clearing one lobe, or the entire liver, with an optical clearing agent, allows for pre-screening of suitably injected samples. In the second part of the DUCT pipeline, a lobe or the whole liver can be used for micro-computed tomography (microCT) scanning, (semi-)automated segmentation, and 3D rendering of the portal venous and biliary networks. MicroCT results in 3D coordinate data for the two resins allowing for qualitative as well as quantitative analysis of the two systems and their spatial relationship. DUCT can be applied to postnatal and adult mouse liver and can be further extended to other tubular networks, for example, vascular networks and airways in the lungs.

Double resin casting micro-computed tomography, or DUCT, enables visualization, digitalization, and segmentation of two tubular systems simultaneously to facilitate 3D analysis of organ architecture. DUCT combines ex vivo injection of two radiopaque resins followed by micro-computed tomography scanning and segmentation of the tomographic data.

The liver is the biggest internal organ in humans and mice, and high auto-fluorescence presents a significant challenge for assessing the ...

Extrahepatic Bile Duct and Gall Bladder Dissection in Nine-Day-Old Mouse Neonates

The dissection of murine neonatal bile ducts has been described as difficult. The main aim of the described standard operating procedure is the isolation of the extrahepatic bile duct (EBD) in mouse neonates without damaging the bile duct during preparation. Because of its exceptionally close preparation compared to the cholangiocytes cell line and harvesting of the entire extrahepatic bile duct system (EBDS), the described approach is extremely useful in researching animal models of newborn bile duct disorders, such as biliary atresia. After euthanasia, the peritoneal cavity was accessed, and the bile duct system, duodenum, and liver were extracted with the unique En-bloc-Resection (EbR). The extracted sample is placed on a foam mat, and the EBD is dissected from contaminating cells atraumatically without necessary touch. The dissection of the entire EBDS is a significant advantage of this method. Caution must be taken due to the small size and amount of bile duct tissue. Using the described technique, there is no damage to the cholangiocytes. Further, the purity of the technique is reproducible (n = 10). Therefore, optimally comparable samples can be harvested. Furthermore, no bile duct tissue is harmed, because any contact with the bile duct system can be avoided during preparation, leaving the bile fluid inside the gall bladder. Most importantly, while performing the final gall bladder and bile duct dissection, atraumatic microinstruments were used only slightly lateral of the bile duct without squeezing it. This is the key to a clean and intact sample, and essential for further histological investigation or the isolation of cholangiocytes. To summarize, the described innovative dissection technique enables especially inexperienced operators with the necessary equipment to isolate the EBDS as cleanly as possible.

For the observation of murine neonatal bile duct disorders, an intact bile duct and efficient preparation are required. Therefore, a new approach for isolating the entire extrahepatic bile duct system in murine neonates was successfully developed while maintaining the integrity of the bile duct.

The dissection of murine neonatal bile ducts has been described as difficult. The main aim of the described standard operating procedure is the isolation ...