Name: three-dimensional collagen matrix scaffold implantation as a liver regeneration strategy
Uploaded: 2021-06-29T14:15:00
Description: Watch this Scientific Journal Video about Three-Dimensional Collagen Matrix Scaffold Implantation as a Liver Regeneration Strategy at JoVE.com

The authors wish to thank the personnel of the Laboratory Animal Facility of the Experimental Medicine Unit, Nurse Carolina Ba&#241;os G. for technical and surgical support, Marco E. Gudi&#241;o Z. for support in microphotographs, and Erick Apo for support in liver histology. The National Council supported this research for Science and Technology (CONACyT), grant number SALUD-2016-272579 and the PAPIIT-UNAM TA200515.

The present research was approved by the ethics committee of the School of Medicine (DI/115/2015) at the Universidad Nacional Aut&#243;noma de M&#233;xico (UNAM) and the ethics committee of the Hospital General de Mexico (CI/314/15). The institution fulfills all technical specifications for the production, care, and use of laboratory animals and is legally certified by national law (NOM-062-ZOO-1999). Male Wistar rats weighing 150-250 g (6-8 weeks old) were obtained from the Laboratory Animal Facility of the School of Me...

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Organ transplantation is the mainstay of treatment in patients with liver fibrosis or cirrhosis. A few patients benefit from this procedure, making it necessary to provide therapeutic alternatives for patients on the waiting list. Tissue engineering is a promising strategy that employs scaffolds and cells with regenerative potential2,4,13. The removal of a portion of the liver is a critical step in this procedure because of the ...

The liver is one of the most important organs involved in maintaining homeostasis and protein production1. Unfortunately, liver disease is the leading cause of death worldwide. In advanced stages of liver damage, which include cirrhosis and hepatocellular carcinoma, liver transplantation is the clinically recommended procedure. However, due to the scarcity of donors and the low rate of successful transplants, new techniques in tissue engineering (TE) and regenerative medicine (RM) have been developed2,3.
TE involves the use of stem cells, scaffolds, and growth factors4 to promote the restoration of inflamed, fibrotic, and edematous organs and tissues1,5,6. The biomaterials used in scaffolds mimic the native ECM, providing the physical, chemical, and biological cues for guided cellular remodeling7. Collagen is one of the most abundant proteins obtained from the dermis, tendon, intestine, and pericardium8,9. Furthermore, collagen can be obtained as a biopolymer to produce two- and three-dimensional scaffolds through bioprinting or electrospinning10,11. This group is the first to report the use of collagen from a bone source for the regeneration of liver tissue. Another study reports the use of scaffolds synthesized from bovine collagen, which was obtained from skin, with homogeneous and closely situated pores, without any communication between them12.
Decellularization preserves the native ECM, allowing the subsequent incorporation of cells with stem cell potential13,14. However, this procedure is still in the experimental phase in the liver, heart, kidney, small intestine, and urinary bladder from mice, rats, rabbits, pigs, sheep, cattle, and horses3,14. Currently, the resected liver mass volume is not replaced in any of the animal hepatectomy models. However, the use of additional support or network (biomaterials) that enables cell proliferation and angiogenesis could be essential for the prompt restoration of liver parenchymal functions. Thus, scaffolds could be employed as alternative approaches to regenerate or repair tissue in chronic liver diseases, in turn, eliminating limitations due to donation and the clinical complications of liver transplantation.

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			<td>Anionic detergent</td>
			<td>Alconox</td>
			<td>Z273228</td>
			<td></td>
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		<tr>
			<td>Biopsy cassettes</td>
			<td>Leica</td>
			<td>3802453</td>
			<td></td>
		</tr>
		<tr>
			<td>Camera DMX</td>
			<td>Nikon</td>
			<td>DXM1200F</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Eppendorf</td>
			<td>5424</td>
			<td></td>
		</tr>
		<tr>
			<td>Chlorhexidine gluconate 4%</td>
			<td>BD</td>
			<td>372412</td>
			<td></td>
		</tr>
		<tr>
			<td>Cover glasses 25 mm x 40 mm</td>
			<td>Corning</td>
			<td>2980-224</td>
			<td></td>
		</tr>
		<tr>
			<td>Eosin</td>
			<td>Sigma-Aldrich</td>
			<td>200-M</td>
			<td>CAS 17372-87-1</td>
		</tr>
		<tr>
			<td>Ethyl alcohol, pure</td>
			<td>Sigma-Aldrich</td>
			<td>459836</td>
			<td>CAS 64-17-5</td>
		</tr>
		<tr>
			<td>Flunixine meglumide</td>
			<td>MSD</td>
			<td>Q-0273-035</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass slides 75 mm x 25 mm</td>
			<td>Corning</td>
			<td>101081022</td>
			<td></td>
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			<td>Hematoxylin</td>
			<td>Merck</td>
			<td>H9627</td>
			<td>CAS 571-28-2</td>
		</tr>
		<tr>
			<td>Hydrochloric acid 37%</td>
			<td>Merck</td>
			<td>339253</td>
			<td>CAS 7647-01-0</td>
		</tr>
		<tr>
			<td>Ketamine</td>
			<td>Pisa agropecuaria</td>
			<td>Q-7833-028</td>
			<td></td>
		</tr>
		<tr>
			<td>Light microscopy</td>
			<td>Nikon</td>
			<td>Microphoto-FXA</td>
			<td></td>
		</tr>
		<tr>
			<td>Microtainer yellow cape</td>
			<td>Beckton Dickinson</td>
			<td>365967</td>
			<td></td>
		</tr>
		<tr>
			<td>Microtome</td>
			<td>Leica</td>
			<td>RM2125</td>
			<td></td>
		</tr>
		<tr>
			<td>Model animal: Wistar rats</td>
			<td>Universidad Nacional Aut&#243;noma de M&#233;xico</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Nylon 3-0 (Dermalon)</td>
			<td>Covidien</td>
			<td>1750-41</td>
			<td></td>
		</tr>
		<tr>
			<td>Polypropylene 7-0</td>
			<td>Atramat</td>
			<td>SE867/2-60</td>
			<td></td>
		</tr>
		<tr>
			<td>Povidone-iodine10% cutaneous solution</td>
			<td>Diafra SA de CV</td>
			<td>1.37E+86</td>
			<td></td>
		</tr>
		<tr>
			<td>Scaning electronic microscopy</td>
			<td>Zeiss</td>
			<td>DSM-950</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium hydroxide, pellets</td>
			<td>J. T. Baker</td>
			<td>3722-01</td>
			<td>CAS 1310-73-2</td>
		</tr>
		<tr>
			<td>Software ACT-1</td>
			<td>Nikon</td>
			<td>Ver 2.70</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereoscopy macroscopy</td>
			<td>Leica</td>
			<td>EZ4Stereo 8X-35X</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterrad 100S</td>
			<td>Johnson and Johnson</td>
			<td>99970</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgipath paraplast</td>
			<td>Leica</td>
			<td>39601006</td>
			<td></td>
		</tr>
		<tr>
			<td>Synringe of 1 mL with needle (27G x 13 mm)</td>
			<td>SensiMedical</td>
			<td>LAN-078-077</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue Processor (Histokinette)</td>
			<td>Leica</td>
			<td>TP1020</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue-Tek TEC 5 (Tissue embedder)</td>
			<td>Sakura Finetek USA</td>
			<td>5229</td>
			<td></td>
		</tr>
		<tr>
			<td>Trichrome stain kit</td>
			<td>Sigma-Aldrich</td>
			<td>HT15</td>
			<td></td>
		</tr>
		<tr>
			<td>Unicell DxC600 Analyzer</td>
			<td>Beckman Coulter</td>
			<td>BC 200-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Xylazine</td>
			<td>Pisa agropecuaria</td>
			<td>Q-7833-099</td>
			<td></td>
		</tr>
		<tr>
			<td>Xylene</td>
			<td>Sigma-Aldrich</td>
			<td>534056</td>
			<td>CAS 1330-20-7</td>
		</tr>
	</tbody>
</table>

three-dimensional collagen matrix scaffold implantation as a liver regeneration strategy

Liver diseases are the leading cause of death worldwide. Excessive alcohol consumption, a high-fat diet, and hepatitis C virus infection promote fibrosis, cirrhosis, and/or hepatocellular carcinoma. Liver transplantation is the clinically recommended procedure to improve and extend the life span of patients in advanced disease stages. However, only 10% of transplants are successful, with organ availability, presurgical and postsurgical procedures, and elevated costs directly correlated with that result. Extracellular matrix (ECM) scaffolds have emerged as an alternative for tissue restoration. Biocompatibility and graft acceptance are the main beneficial characteristics of those biomaterials. Although the capacity to restore the size and correct function of the liver has been evaluated in liver hepatectomy models, the use of scaffolds or some kind of support to replace the volume of the extirpated liver mass has not been assessed.
Partial hepatectomy was performed in a rat liver with the xenoimplantation of a collagen matrix scaffold (CMS) from a bovine condyle. Left liver lobe tissue was removed (approximately 40%), and an equal proportion of CMS was surgically implanted. Liver function tests were evaluated before and after the surgical procedure. After days 3, 14, and 21, the animals were euthanized, and macroscopic and histologic evaluations were performed. On days 3 and 14, adipose tissue was observed surrounding the CMS, with no clinical evidence of rejection or infection, as was vessel neoformation and CMS reabsorption at day 21. There was histologic evidence of an insignificant inflammation process and migration of adjacent cells to the CMS, observed with the hematoxylin and eosin (H&#38;E) and Masson&#39;s trichrome staining. The CMS was shown to perform well in liver tissue and could be a useful alternative for studying tissue regeneration and repair in chronic liver diseases.

Bone demineralization affects the mechanical properties of CMS without altering the original shape or interconnection of its pores. CMS can have any shape, and therefore, can be adjusted to the size and shape of the selected organ or tissue19. In the present protocol, we used a triangular CMS (Figure 1A-D). A rat model was used to evaluate the regenerative capacity of the CMS xenoimplant in the liver. Although the liv...

Watch this Scientific Journal Video about Three-Dimensional Collagen Matrix Scaffold Implantation as a Liver Regeneration Strategy at JoVE.com

Three-Dimensional Collagen Matrix Scaffold Implantation as a Liver Regeneration Strategy

Liver diseases are induced by many causes that promote fibrosis or cirrhosis. Transplantation is the only option for recovering health. However, given the scarcity of transplantable organs, alternatives must be explored. Our research proposes the implantation of collagen scaffolds in liver tissue from an animal model.

Liver diseases are the leading cause of death worldwide. Excessive alcohol consumption, a high-fat diet, and hepatitis C virus infection promote fibrosis, ...

This method involves placing an implant of collagen matrix as a scaffold in the liver to promote liver regeneration. This implantation method has opened the door for a strategist exploring the restoration of the shape and balloon of the resected tissues, thereby reducing anesthesia, surgical duration, and recovery time. This method can be used to promote regeneration involving models of liver fibrosis, as well as other mammalian species.This method is based on tissue engineering and regenerative medicine to promote the restoration of injured tissue. Begin by sanitizing the surgical area work table, microsurgery microscope, and seat with a 2%chlorhexidine solution, then hydrate the collagen matrix scaffold obtained from a bovine condyle in sterile saline solution for 20 minutes. Next, using surgical soap and a double-edged blade, shave the abdominal skin of an anesthetized six to eight-week-old male Wistar rat, then disinfect the skin three times using a 10%povidone iodine solution.Place the animal on a warm plate in the decubitus dorsal position with the neck hyperextended to maintain a permeable airway. Evaluate the depth of anesthesia through the respiratory pattern and loss of withdrawal reflex in the limbs. Then place a disposable surgical drape around the shaved skin and using the xiphoid process as a reference point, make a 2.5 centimeter incision on the alpis line with dissection forceps, taking care to avoid the abdominal wall blood vessel to prevent bleeding.After placing the abdominal retractor, observe the abdominal cavity. Using the dissection forceps, extract the left liver lobe and place it on the metal plate. Using a sterile one by one by one centimeter triangular metallic template, perform a hepatectomy.To prevent bleeding of the liver, maintain surgical compression with a swab on the edge of the liver for five minutes. Next, using 7-O non-absorbable polypropylene sutures, implant the hydrated collagen matrix scaffold in the hepatectomy site with four stitches between the liver tissue and the scaffold to prevent displacement of the biomaterial. Return the liver to the abdominal cavity and suture the abdominal wall and skin with a 3-O nylon suture.Clean the surgical incision twice with a surgical iodine-soaked sponge and monitor the vital signs of the animal. Then place the animal in lateral decubitus position. After administering an analgesic, place the animal in an individual polycarbonate box with laboratory animal bedding in a noise-free area with temperature control.Observe the recovery from anesthesia and monitor water and food consumption for two hours. There was no difference in the liver function between the SHAM group and the experimental groups with and without the collagen matrix scaffold at three, 14, and 21 days, indicating that the collagen matrix scaffold does not disrupt liver function. Histological analysis on day three shows that the presence of the collagen matrix scaffold in the liver did not promote a foreign body reaction and the conspicuous presence of lax connective tissue is observed.On days 14 and 21, the lax connective tissue is more abundant with the collagen matrix scaffold trabeculae surrounded by hepatocytes suggesting that hepatocytes have migrated to the collagen matrix scaffold. Areas of hepatocytes irrigated by a vessel can be seen and the hepatocytes adhering to the collagen matrix scaffold trabeculae are sometimes surrounded by lax connective tissue. While performing the hepatectomy, use aseptic technique to avoid infection and apply compression afterwards to prevent bleeding from the liver.Also, use 7-O sutures for implantation of collagen matrix scaffold to avoid tearing. After implantation of the collagen matrix scaffold in a fibrotic animal model, the advantages of sinogenic implantation for liver regeneration can be evaluated. The use of collagen matrix scaffold to replace the liver extubated mass has not been evaluated until now.These genogenic materials paves the way as another therapeutic option in the field of the chronic liver diseases.

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Medicine

A Strategy to Identify de Novo Mutations in Common Disorders such as Autism and Schizophrenia

There are several lines of evidence supporting the role of de novo mutations as a mechanism for common disorders, such as autism and schizophrenia. First, the de novo mutation rate in humans is relatively high, so new mutations are generated at a high frequency in the population. However, de novo mutations have not been reported in most common diseases. Mutations in genes leading to severe diseases where there is a strong negative selection against the phenotype, such as lethality in embryonic stages or reduced reproductive fitness, will not be transmitted to multiple family members, and therefore will not be detected by linkage gene mapping or association studies. The observation of very high concordance in monozygotic twins and very low concordance in dizygotic twins also strongly supports the hypothesis that a significant fraction of cases may result from new mutations. Such is the case for diseases such as autism and schizophrenia. Second, despite reduced reproductive fitness1 and extremely variable environmental factors, the incidence of some diseases is maintained worldwide at a relatively high and constant rate. This is the case for autism and schizophrenia, with an incidence of approximately 1% worldwide. Mutational load can be thought of as a balance between selection for or against a deleterious mutation and its production by de novo mutation. Lower rates of reproduction constitute a negative selection factor that should reduce the number of mutant alleles in the population, ultimately leading to decreased disease prevalence. These selective pressures tend to be of different intensity in different environments. Nonetheless, these severe mental disorders have been maintained at a constant relatively high prevalence in the worldwide population across a wide range of cultures and countries despite a strong negative selection against them2. This is not what one would predict in diseases with reduced reproductive fitness, unless there was a high new mutation rate. Finally, the effects of paternal age: there is a significantly increased risk of the disease with increasing paternal age, which could result from the age related increase in paternal de novo mutations. This is the case for autism and schizophrenia3. The male-to-female ratio of mutation rate is estimated at about 4&#x2013;6:1, presumably due to a higher number of germ-cell divisions with age in males. Therefore, one would predict that de novo mutations would more frequently come from males, particularly older males4. A high rate of new mutations may in part explain why genetic studies have so far failed to identify many genes predisposing to complexes diseases genes, such as autism and schizophrenia, and why diseases have been identified for a mere 3% of genes in the human genome. Identification for de novo mutations as a cause of a disease requires a targeted molecular approach, which includes studying parents and affected subjects. The process for determining if the genetic basis of a disease may result in part from de novo mutations and the molecular approach to establish this link will be illustrated, using autism and schizophrenia as examples.

Molecular genetic strategy for finding de novo mutations causing common disorders such as autism and schizophrenia.

There are several lines of evidence supporting the role of de novo mutations as a mechanism for common disorders, such as autism and schizophrenia. First, ...

Human Neuroendocrine Tumor Cell Lines as a Three-Dimensional Model for the Study of Human Neuroendocrine Tumor Therapy

Neuroendocrine tumors (NETs) are rare tumors, with an incidence of two per 100,&#x200A;000 individuals per year, and they account for 0.5% of all human malignancies.1 Other than surgery for the minority of patients who present with localized disease, there is little or no survival benefit of systemic therapy. Therefore, there is a great need to better understand the biology of NETs, and in particular define new therapeutic targets for patients with nonresectable or metastatic neuroendocrine tumors. 3D cell culture is becoming a popular method for drug screening due to its relevance in modeling the in vivo tumor tissue organization and microenvironment.2,3 The 3D multicellular spheroids could provide valuable information in a more timely and less expensive manner than directly proceeding from 2D cell culture experiments to animal (murine) models.
To facilitate the discovery of new therapeutics for NET patients, we have developed an in vitro 3D multicellular spheroids model using the human NET cell lines. The NET cells are plated in a non-adhesive agarose-coated 24-well plate and incubated under physiological conditions (5% CO2, 37 &deg;C) with a very slow agitation for 16-24 hr after plating. The cells form multicellular spheroids starting on the 3rd or 4th day. The spheroids become more spherical by the 6th day, at which point the drug treatments are initiated. The efficacy of the drug treatments on the NET spheroids is monitored based on the morphology, shape and size of the spheroids with a phase-contrast light microscope. The size of the spheroids is estimated automatically using a custom-developed MATLAB program based on an active contour algorithm. Further, we demonstrate a simple method to process the HistoGel embedding on these 3D spheroids, allowing the use of standard histological and immunohistochemical techniques. 
This is the first report on generating 3D spheroids using NET cell lines to examine the effect of therapeutic drugs. We have also performed histology on these 3D spheroids, and displayed an example of a single drug's effect on growth and proliferation of the NET spheroids. Our results support that the NET spheroids are valuable for further studies of NET biology and drug development.

We present a simple agarose overlay platform to grow 3D multicellular spheroids using neuroendocrine cancer cell lines. This method provides a very convenient way to examine the effect of therapeutic drugs on the neuroendocrine tumor cells. It could also help us establish human neuroendocrine tumor spheroids for cancer therapy.

Neuroendocrine tumors (NETs) are rare tumors, with an incidence of two per 100,&#x200A;000 individuals per year, and they account for 0.5% of all human ...

Quantification of Breast Cancer Cell Invasiveness Using a Three-dimensional (3D) Model

It is now well known that the cellular and tissue microenvironment are critical regulators influencing tumor initiation and progression. Moreover, the extracellular matrix (ECM) has been demonstrated to be a critical regulator of cell behavior in culture and homeostasis in vivo. The current approach of culturing cells on two-dimensional (2D), plastic surfaces results in the disturbance and loss of complex interactions between cells and their microenvironment. Through the use of three-dimensional (3D) culture assays, the conditions for cell-microenvironment interaction are established resembling the in vivo microenvironment. This article provides a detailed methodology to grow breast cancer cells in a 3D basement membrane protein matrix, exemplifying the potential of 3D culture in the assessment of cell invasion into the surrounding environment. In addition, we discuss how these 3D assays have the potential to examine the loss of signaling molecules that regulate epithelial morphology by immunostaining procedures. These studies aid to identify important mechanistic details into the processes regulating invasion, required for the spread of breast cancer.

Quantification of Breast Cancer Cell Invasiveness Using a Three-dimensional 3D Model

This article provides detailed methodologies for the use of three-dimensional (3D) assays to quantify breast cancer cell invasion. Specifically, we discuss the procedures required to set up such assays, quantification, and data analysis, as well as methods to examine the loss of membrane integrity that occurs when cells invade.

It is now well known that the cellular and tissue microenvironment are critical regulators influencing tumor initiation and progression. Moreover, the ...

Isolated Hepatic Perfusion as a Treatment for Liver Metastases of Uveal Melanoma

Isolated hepatic perfusion (IHP) is a procedure where the liver is surgically isolated and perfused with a high concentration of the chemotherapeutic agent melphalan. Briefly, the procedure starts with the setup of a percutaneous veno-venous bypass from the femoral vein to the external jugular vein. Via a laparotomy, catheters are then inserted into the proper hepatic artery and the caval vein. The portal vein and the caval vein, both supra- and infrahepatically, are then clamped. The arterial and venous catheters are connected to a heart lung machine and the liver is perfused with melphalan (1 mg/kg body weight) for 60 min. This way it is possible to locally perfuse the liver with a high dose of a chemotherapeutic agent, without leakage to the systemic circulation.
In previous studies including patients with isolated liver metastases of uveal melanoma, an overall response rate of 33-100% and a median survival between 9 and 13 months, have been reported. The aim of this protocol is to give a clear description of how to perform the procedure and to discuss IHP as a treatment option for liver metastases of uveal melanoma.

Here, we present a protocol how to perform an isolated liver perfusion (IHP) with melphalan and we also discuss IHP as a treatment option for liver metastases of uveal melanoma.

Isolated hepatic perfusion (IHP) is a procedure where the liver is surgically isolated and perfused with a high concentration of the chemotherapeutic ...

Three-Dimensional (3D) Tumor Spheroid Invasion Assay

Invasion of surrounding normal tissues is generally considered to be a key hallmark of malignant (as opposed to benign) tumors. For some cancers in particular (e.g., brain tumors such as glioblastoma multiforme and squamous cell carcinoma of the head and neck &#8211; SCCHN) it is a cause of severe morbidity and can be life-threatening even in the absence of distant metastases. In addition, cancers which have relapsed following treatment unfortunately often present with a more aggressive phenotype. Therefore, there is an opportunity to target the process of invasion to provide novel therapies that could be complementary to standard anti-proliferative agents. Until now, this strategy has been hampered by the lack of robust, reproducible assays suitable for a detailed analysis of invasion and for drug screening. Here we provide a simple micro-plate method (based on uniform, self-assembling 3D tumor spheroids) which has great potential for such studies. We exemplify the assay platform using a human glioblastoma cell line and also an SCCHN model where the development of resistance against targeted epidermal growth factor receptor (EGFR) inhibitors is associated with enhanced matrix-invasive potential. We also provide two alternative methods of semi-automated quantification: one using an imaging cytometer and a second which simply requires standard microscopy and image capture with digital image analysis.

Three-Dimensional 3D Tumor Spheroid Invasion Assay

Invasion of surrounding normal tissues is a defining characteristic of malignant tumors. We provide here a simple, semi-automated micro-plate assay of invasion into a natural 3D biomatrix that has been exemplified with a number of models of advanced human cancers.

Invasion of surrounding normal tissues is generally considered to be a key hallmark of malignant (as opposed to benign) tumors. For some cancers in ...

Method of Direct Segmental Intra-hepatic Delivery Using a Rat Liver Hilar Clamp Model

Major hepatic surgery with inflow occlusion, and liver transplantation, necessitate a period of warm ischemia, and a period of reperfusion leading to ischemia/reperfusion (I/R) injury with myriad negative consequences. Potential I/R injury in marginal organs destined for liver transplantation contributes to the current donor shortage secondary to a decreased organ utilization rate. A significant need exists to explore hepatic I/R injury in order to mediate its impact on graft function in transplantation. Rat liver hilar clamp models are used to investigate the impact of different molecules on hepatic I/R injury. Depending on the model, these molecules have been delivered using inhalation, epidural infusion, intraperitoneal injection, intravenous administration or injection into the peripheral superior mesenteric vein. A rat liver hilar clamp model has been developed for use in studying the impact of pharmacologic molecules in ameliorating I/R injury. The described model for rat liver hilar clamp includes direct cannulation of the portal supply to the ischemic hepatic segment via a side branch of the portal vein, allowing for direct segmental hepatic delivery. Our approach is to induce ischemia in the left lateral and median lobes for 60 min, during which time the substance under study is infused. In this case, pegylated-superoxide dismutase (PEG-SOD), a free radical scavenger, is infused directly into the ischemic segment. This series of experiments demonstrates that infusion of PEG-SOD is protective against hepatic I/R injury. Advantages of this approach include direct injection of the molecule into the ischemic segment with consequent decrease in volume of distribution and reduction in systemic side effects.

A unique rat liver hilar clamp model was developed for studying the impact of pharmacologic molecules in ameliorating ischemia-reperfusion injury. This model includes direct cannulation of the portal supply to the ischemic liver segment via a branch of the portal vein, allowing for direct hepatic delivery.

Major hepatic surgery with inflow occlusion, and liver transplantation, necessitate a period of warm ischemia, and a period of reperfusion leading to ...

Three-Dimensional Printing of a Complex Aortic Anomaly

Complex congenital aortic anomalies include diverse types of malformations that may be clinically asymptomatic or present with respiratory or esophageal symptoms. These anomalies may be associated with other congenital heart diseases. It is hard to identify the accurate anatomic vessel location from two-dimensional imaging data, such as computed tomography. As an additive manufacturing method, three-dimensional (3-D) printing can covert the acquired imaging data into 3-D physical models. This protocol describes the procedure for modeling the volumetric DICOM imaging into 3-D data and printing it as an anatomically realistic 3-D model. Using this model, surgeons can identify the vessel location of complex aortic anomalies, which is helpful for pre-operative planning and intra-operative guidance.

Here, we present a protocol to use three dimensional printed models for pre-operative planning and intra-operative reorganization of complicated vascular locations when handling a congenital aortic anomaly.

Complex congenital aortic anomalies include diverse types of malformations that may be clinically asymptomatic or present with respiratory or esophageal ...

Murine Precision-Cut Liver Slices as an Ex Vivo Model of Liver Biology

Understanding the mechanisms of liver injury, hepatic fibrosis, and cirrhosis that underlie chronic liver diseases (i.e., viral hepatitis, non-alcoholic fatty liver disease, metabolic liver disease, and liver cancer) requires experimental manipulation of animal models and in vitro cell cultures. Both techniques have limitations, such as the requirement of large numbers of animals for in vivo manipulation. However, in vitro cell cultures do not reproduce the structure and function of the multicellular hepatic environment. The use of precision-cut liver slices is a technique in which uniform slices of viable mouse liver are maintained in laboratory tissue culture for experimental manipulation. This technique occupies an experimental niche that exists between animal studies and in vitro cell culture methods. The presented protocol describes a straightforward and reliable method to isolate and culture precision-cut liver slices from mice. As an application of this technique, ex vivo liver slices are treated with bile acids to simulate cholestatic liver injury and ultimately assess the mechanisms of hepatic fibrogenesis.

This protocol provides a simple and reliable method for the production of viable precision-cut liver slices from mice. The ex vivo tissue samples can be maintained under laboratory tissue culture conditions for multiple days, providing a flexible model to examine liver pathobiology.

Understanding the mechanisms of liver injury, hepatic fibrosis, and cirrhosis that underlie chronic liver diseases (i.e., viral hepatitis, non-alcoholic ...

3D Imaging of the Liver Extracellular Matrix in a Mouse Model of Non-Alcoholic Steatohepatitis

Non-alcoholic steatohepatitis (NASH) is the most common chronic liver disease in the United States, affecting more than 70 million Americans. NASH can progress to fibrosis and eventually to cirrhosis, a significant risk factor for hepatocellular carcinoma. The extracellular matrix (ECM) provides structural support and maintains liver homeostasis via matricellular signals. Liver fibrosis results from an imbalance in the dynamic ECM remodeling process and is characterized by excessive accumulation of structural elements and associated changes in glycosaminoglycans. The typical fibrosis pattern of NASH is called &#34;chicken wire,&#34; which usually consists of zone 3 perisinusoidal/pericellular fibrosis, based on features observed by Masson&#39;s trichrome stain and Picrosirius Red stains. However, these traditional thin two-dimensional (2D) tissue slide-based imaging techniques cannot demonstrate the detailed three-dimensional (3D) ECM structural changes, limiting the understanding of the dynamic ECM remodeling in liver fibrosis.
The current work optimized a fast and efficient protocol to image the native ECM structure in the liver via decellularization to address the above challenges. Mice were fed either with chow or fast-food diet for 14 weeks. Decellularization was performed after in situ portal vein perfusion, and the two-photon microscopy techniques were applied to image and analyze changes in the native ECM. The 3D images of the normal and NASH livers were reconstituted and analyzed. Performing in situ perfusion decellularization and analyzing the scaffold by two-photon microscopy provided a practical and reliable platform to visualize the dynamic ECM remodeling in the liver.

The present protocol optimizes the liver in situ perfusion/decellularization and two-photon microscopy methods to establish a reliable platform to visualize the dynamics of extracellular matrix (ECM) remodeling during non-alcoholic steatohepatitis (NASH).

Non-alcoholic steatohepatitis (NASH) is the most common chronic liver disease in the United States, affecting more than 70 million Americans. NASH can ...

Whole-Kidney Three-Dimensional Staining with CUBIC

Although conventional pathology provided numerous information about kidney microstructure, it was difficult to know the precise structure of blood vessels, proximal tubules, collecting ducts, glomeruli, and sympathetic nerves in the kidney due to the lack of three-dimensional (3D) information. Optical clearing is a good strategy to overcome this big hurdle. Multiple cells in a whole organ can be analyzed at single-cell resolution by combining tissue clearing and 3D imaging technique. However, cell labeling methods for whole-organ imaging remain underdeveloped. In particular, whole-mount organ staining is challenging because of the difficulty in antibody penetration. The present protocol developed a whole-mount mouse kidney staining for 3D imaging with the CUBIC (Clear, Unobstructed Brain/Body Imaging Cocktails and Computational analysis) tissue clearing method. The protocol has enabled visualizing renal sympathetic denervation after ischemia-reperfusion injury and glomerulomegaly in the early stage of diabetic kidney disease from a comprehensive viewpoint. Thus, this technique can lead to new discoveries in kidney research by providing a macroscopic perspective.

The present protocol describes a tissue clearing method and whole-mount immunofluorescent staining for three-dimensional (3D) kidney imaging. This technique can offer macroscopic perspectives in kidney pathology, leading to new biological discoveries.