1
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Tithof J, Pruett TL, Rao JS. Lumped parameter liver simulation to predict acute haemodynamic alterations following partial resections. J R Soc Interface 2023; 20:20230444. [PMID: 37876272 PMCID: PMC10598422 DOI: 10.1098/rsif.2023.0444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 10/02/2023] [Indexed: 10/26/2023] Open
Abstract
Partial liver resections are routinely performed in living donor liver transplantation and to debulk tumours in liver malignancies, but surgical decisions on vessel reconstruction for adequate inflow and outflow are challenging. Pre-operative evaluation is often limited to radiological imaging, which fails to account for post-resection haemodynamic alterations. Substantial evidence suggests post-surgical increase in local volume flow rate enhances shear stress, signalling hepatic regeneration, but excessive shear stress has been postulated to result in small for size syndrome and liver failure. Predicting haemodynamic alterations throughout the liver is particularly challenging due to the dendritic architecture of the vasculature, spanning several orders of magnitude in diameter. Therefore, we developed a mathematical lumped parameter model with realistic heterogeneities capturing inflow/outflow of the human liver to simulate acute perfusion alterations following surgical resection. Our model is parametrized using clinical measurements, relies on a single free parameter and accurately captures established perfusion characteristics. We quantify acute changes in volume flow rate, flow speed and wall shear stress following variable, realistic liver resections and make comparisons with the intact liver. Our numerical model runs in minutes and can be adapted to patient-specific anatomy, providing a novel computational tool aimed at assisting pre- and intra-operative surgical decisions for liver resections.
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Affiliation(s)
- Jeffrey Tithof
- Department of Mechanical Engineering, University of Minnesota, 111 Church Street SE, Minneapolis, MN 55455, USA
| | - Timothy L. Pruett
- Division of Solid Organ Transplantation, Department of Surgery, University of Minnesota, Minneapolis, MN, USA
| | - Joseph Sushil Rao
- Division of Solid Organ Transplantation, Department of Surgery, University of Minnesota, Minneapolis, MN, USA
- Schulze Diabetes Institute, Department of Surgery, University of Minnesota, 420 Delaware Street SE, Minneapolis, MN 55455, USA
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2
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Hess S, Kendall TJ, Pena M, Yamane K, Soong D, Adams L, Truman R, Rambukkana A. In vivo partial reprogramming by bacteria promotes adult liver organ growth without fibrosis and tumorigenesis. Cell Rep Med 2022; 3:100820. [PMID: 36384103 PMCID: PMC9729881 DOI: 10.1016/j.xcrm.2022.100820] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 05/04/2022] [Accepted: 10/18/2022] [Indexed: 11/17/2022]
Abstract
Ideal therapies for regenerative medicine or healthy aging require healthy organ growth and rejuvenation, but no organ-level approach is currently available. Using Mycobacterium leprae (ML) with natural partial cellular reprogramming capacity and its animal host nine-banded armadillos, we present an evolutionarily refined model of adult liver growth and regeneration. In infected armadillos, ML reprogram the entire liver and significantly increase total liver/body weight ratio by increasing healthy liver lobules, including hepatocyte proliferation and proportionate expansion of vasculature, and biliary systems. ML-infected livers are microarchitecturally and functionally normal without damage, fibrosis, or tumorigenesis. Bacteria-induced reprogramming reactivates liver progenitor/developmental/fetal genes and upregulates growth-, metabolism-, and anti-aging-associated markers with minimal change in senescence and tumorigenic genes, suggesting bacterial hijacking of homeostatic, regeneration pathways to promote de novo organogenesis. This may facilitate the unraveling of endogenous pathways that effectively and safely re-engage liver organ growth, with broad therapeutic implications including organ regeneration and rejuvenation.
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Affiliation(s)
- Samuel Hess
- Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, UK; Centre for Regenerative Medicine, The University of Edinburgh, Edinburgh, UK
| | - Timothy J Kendall
- Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, UK; Centre for Inflammation Research, The University of Edinburgh, Edinburgh, UK; Edinburgh Pathology, The University of Edinburgh, Edinburgh, UK
| | - Maria Pena
- US Department of Health and Human Services, Health Resources and Services Administration, Healthcare Systems Bureau, National Hansen's Disease Program, Baton Rouge, LA, USA
| | - Keitaro Yamane
- Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, UK; Centre for Regenerative Medicine, The University of Edinburgh, Edinburgh, UK
| | - Daniel Soong
- Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, UK; Medical Research Council Centre for Reproductive Health, The University of Edinburgh, Edinburgh, UK
| | - Linda Adams
- US Department of Health and Human Services, Health Resources and Services Administration, Healthcare Systems Bureau, National Hansen's Disease Program, Baton Rouge, LA, USA
| | - Richard Truman
- US Department of Health and Human Services, Health Resources and Services Administration, Healthcare Systems Bureau, National Hansen's Disease Program, Baton Rouge, LA, USA; Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
| | - Anura Rambukkana
- Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, UK; Centre for Regenerative Medicine, The University of Edinburgh, Edinburgh, UK; Edinburgh Infectious Diseases, The University of Edinburgh, Edinburgh, UK; Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK.
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3
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Utilizing virtual experiments to increase understanding of discrepancies involving in vitro-to-in vivo predictions of hepatic clearance. PLoS One 2022; 17:e0269775. [PMID: 35867653 PMCID: PMC9307204 DOI: 10.1371/journal.pone.0269775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 05/29/2022] [Indexed: 11/19/2022] Open
Abstract
Predictions of xenobiotic hepatic clearance in humans using in vitro-to-in vivo extrapolation methods are frequently inaccurate and problematic. Multiple strategies are being pursued to disentangle responsible mechanisms. The objective of this work is to evaluate the feasibility of using insights gained from independent virtual experiments on two model systems to begin unraveling responsible mechanisms. The virtual culture is a software analog of hepatocytes in vitro, and the virtual human maps to hepatocytes within a liver within an idealized model human. Mobile objects (virtual compounds) map to amounts of xenobiotics. Earlier versions of the two systems achieved quantitative validation targets for intrinsic clearance (virtual culture) and hepatic clearance (virtual human). The major difference between the two systems is the spatial organization of the virtual hepatocytes. For each pair of experiments (virtual culture, virtual human), hepatocytes are configured the same. Probabilistic rules govern virtual compound movements and interactions with other objects. We focus on highly permeable virtual compounds and fix their extracellular unbound fraction at one of seven values (0.05–1.0). Hepatocytes contain objects that can bind and remove compounds, analogous to metabolism. We require that, for a subset of compound properties, per-hepatocyte compound exposure and removal rates during culture experiments directly predict corresponding measures made during virtual human experiments. That requirement serves as a cross-system validation target; we identify compound properties that enable achieving it. We then change compound properties, ceteris paribus, and provide model mechanism-based explanations for when and why measures made during culture experiments under- (or over-) predict corresponding measures made during virtual human experiments. The results show that, from the perspective of compound removal, the organization of hepatocytes within virtual livers is more efficient than within cultures, and the greater the efficiency difference, the larger the underprediction. That relationship is noteworthy because most in vitro-to-in vivo extrapolation methods abstract away the structural organization of hepatocytes within a liver. More work is needed on multiple fronts, including the study of an expanded variety of virtual compound properties. Nevertheless, the results support the feasibility of the approach and plan.
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4
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Mîndrilă B, Buteică SA, Mîndrilă I, Mihaiescu DE, Mănescu MD, Rogoveanu I. Administration Routes as Modulators of the Intrahepatic Distribution and Anti-Anemic Activity of Salicylic Acid/Fe3O4 Nanoparticles. Biomedicines 2022; 10:biomedicines10051213. [PMID: 35625949 PMCID: PMC9138897 DOI: 10.3390/biomedicines10051213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 05/19/2022] [Accepted: 05/21/2022] [Indexed: 11/16/2022] Open
Abstract
The liver is a key organ in the pharmacokinetics of iron oxide nanoparticles (IONPs). This paper examined how the intravenous (IV) or intragastric (IG) route of administration influenced the intrahepatic distribution or therapeutic effects of IONPs. Wistar rats, some with bleeding-induced anemia, and iron oxide nanoparticles functionalized with salicylic acid (SaIONPs), with an average hydrodynamic diameter of 73 nm, compatible with rat sinusoid fenestrations, were used in this study. Light microscopy and multispectral camera analysis of Prussian blue labeled SaIONPs allowed mapping of intrahepatic nanoparticle deposits and revealed intrahepatic distribution patterns specific to each route of administration: loading of Kupffer cells and periportal hepatocytes when the IV route was used and predominant loading of hepatocytes when the IG route was used. Reducing the time to return to baseline values for hemoglobin (HGB) in rats with bleeding-induced anemia with IV or IG therapy has proven the therapeutic potential of SaIONPs in such anemias. The long-term follow-up showed that IV therapy resulted in higher HGB values. Proper use of the administration routes may modulate intrahepatic distribution and therapeutic effects of nanoparticles. These results may be beneficial in theragnosis of liver disease.
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Affiliation(s)
- Bogdan Mîndrilă
- Doctoral School, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania; (B.M.); (M.-D.M.)
| | - Sandra-Alice Buteică
- Faculty of Pharmacy, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania;
| | - Ion Mîndrilă
- Department of Morphology, Faculty of Medicine, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania
- Correspondence:
| | - Dan-Eduard Mihaiescu
- Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 011061 Bucharest, Romania;
| | - Marina-Daniela Mănescu
- Doctoral School, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania; (B.M.); (M.-D.M.)
| | - Ion Rogoveanu
- Department of Gastroenterology, Faculty of Medicine, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania;
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5
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Multiscale reconstruction of various vessels in the intact murine liver lobe. Commun Biol 2022; 5:260. [PMID: 35332265 PMCID: PMC8948268 DOI: 10.1038/s42003-022-03221-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 03/01/2022] [Indexed: 11/09/2022] Open
Abstract
The liver contains a variety of vessels and participates in miscellaneous physiological functions. While past studies generally focused on certain hepatic vessels, we simultaneously obtained all the vessels and cytoarchitectural information of the intact mouse liver lobe at single-cell resolution. Here, taking structural discrepancies of various vessels into account, we reconstruct and visualize the portal vein, hepatic vein, hepatic artery, intrahepatic bile duct, intrahepatic lymph of an intact liver lobe and peribiliary plexus in its selected local areas, providing a technology roadmap for studying the fine hepatic vascular structures and their spatial relationship, which will help research into liver diseases and evaluation of medical efficacies in the future.
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6
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Budelmann D, Laue H, Weiss N, Dahmen U, D'Alessandro LA, Biermayer I, Klingmüller U, Ghallab A, Hassan R, Begher-Tibbe B, Hengstler JG, Schwen LO. Automated Detection of Portal Fields and Central Veins in Whole-Slide Images of Liver Tissue. J Pathol Inform 2022; 13:100001. [PMID: 35242441 PMCID: PMC8860737 DOI: 10.1016/j.jpi.2022.100001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 11/30/2021] [Indexed: 02/07/2023] Open
Abstract
Many physiological processes and pathological phenomena in the liver tissue are spatially heterogeneous. At a local scale, biomarkers can be quantified along the axis of the blood flow, from portal fields (PFs) to central veins (CVs), i.e., in zonated form. This requires detecting PFs and CVs. However, manually annotating these structures in multiple whole-slide images is a tedious task. We describe and evaluate a fully automated method, based on a convolutional neural network, for simultaneously detecting PFs and CVs in a single stained section. Trained on scans of hematoxylin and eosin-stained liver tissue, the detector performed well with an F1 score of 0.81 compared to annotation by a human expert. It does, however, not generalize well to previously unseen scans of steatotic liver tissue with an F1 score of 0.59. Automated PF and CV detection eliminates the bottleneck of manual annotation for subsequent automated analyses, as illustrated by two proof-of-concept applications: We computed lobulus sizes based on the detected PF and CV positions, where results agreed with published lobulus sizes. Moreover, we demonstrate the feasibility of zonated quantification of biomarkers detected in different stainings based on lobuli and zones obtained from the detected PF and CV positions. A negative control (hematoxylin and eosin) showed the expected homogeneity, a positive control (glutamine synthetase) was quantified to be strictly pericentral, and a plausible zonation for a heterogeneous F4/80 staining was obtained. Automated detection of PFs and CVs is one building block for automatically quantifying physiologically relevant heterogeneity of liver tissue biomarkers. Perspectively, a more robust and automated assessment of zonation from whole-slide images will be valuable for parameterizing spatially resolved models of liver metabolism and to provide diagnostic information.
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Affiliation(s)
| | | | | | - Uta Dahmen
- Experimental Transplantation Surgery, Department of General, Visceral and Vascular Surgery, University Hospital Jena, Jena, Germany
| | - Lorenza A D'Alessandro
- Deutsches Krebsforschungszentrum, Systems Biology of Signal Transduction, Heidelberg, Germany
| | - Ina Biermayer
- Deutsches Krebsforschungszentrum, Systems Biology of Signal Transduction, Heidelberg, Germany
| | - Ursula Klingmüller
- Deutsches Krebsforschungszentrum, Systems Biology of Signal Transduction, Heidelberg, Germany
| | - Ahmed Ghallab
- Leibniz Research Centre for Working Environment and Human Factors at the Technical University Dortmund, Dortmund, Germany.,Department of Forensic Medicine and Toxicology, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt
| | - Reham Hassan
- Leibniz Research Centre for Working Environment and Human Factors at the Technical University Dortmund, Dortmund, Germany.,Department of Forensic Medicine and Toxicology, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt
| | - Brigitte Begher-Tibbe
- Leibniz Research Centre for Working Environment and Human Factors at the Technical University Dortmund, Dortmund, Germany
| | - Jan G Hengstler
- Leibniz Research Centre for Working Environment and Human Factors at the Technical University Dortmund, Dortmund, Germany
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7
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Lau C, Kalantari B, Batts KP, Ferrell LD, Nyberg SL, Graham RP, Moreira RK. The Voronoi theory of the normal liver lobular architecture and its applicability in hepatic zonation. Sci Rep 2021; 11:9343. [PMID: 33927276 PMCID: PMC8085188 DOI: 10.1038/s41598-021-88699-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 04/12/2021] [Indexed: 11/24/2022] Open
Abstract
The precise characterization of the lobular architecture of the liver has been subject of investigation since the earliest historical publications, but an accurate model to describe the hepatic lobular microanatomy is yet to be proposed. Our aim was to evaluate whether Voronoi diagrams can be used to describe the classic liver lobular architecture. We examined the histology of normal porcine and human livers and analyzed the geometric relationships of various microanatomic structures utilizing digital tools. The Voronoi diagram model described the organization of the hepatic classic lobules with overall accuracy nearly 90% based on known histologic landmarks. We have also designed a Voronoi-based algorithm of hepatic zonation, which also showed an overall zonal accuracy of nearly 90%. Therefore, we have presented evidence that Voronoi diagrams represent the basis of the two-dimensional organization of the normal liver and that this concept may have wide applicability in liver pathology and research.
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Affiliation(s)
- C Lau
- Department of Computer Science, Rutgers University, Brunswick, NJ, USA
| | - B Kalantari
- Department of Computer Science, Rutgers University, Brunswick, NJ, USA
| | | | - L D Ferrell
- Department of Pathology, University of California, San Francisco, CA, USA
| | - S L Nyberg
- Division of Transplantation Surgery, Department of Surgery, Mayo Clinic, Rochester, MN, USA
| | - R P Graham
- Department of Pathology and Laboratory Medicine, Mayo Clinic, Rochester, MN, USA
| | - Roger K Moreira
- Department of Pathology and Laboratory Medicine, Mayo Clinic, Rochester, MN, USA.
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8
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Liu JY, Lv WJ, Jian JB, Xin XH, Zhao XY, Hu CH. High-resolution three-dimensional visualization of hepatic sinusoids in cirrhotic rats via serial histological sections. Histol Histopathol 2021; 36:577-586. [PMID: 33851410 DOI: 10.14670/hh-18-339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
AIM As a specialized intraparenchymal vascular conduit, hepatic sinusoids play a key role in liver microcirculation. This study aimed to explore the three-dimensional (3D) morphological changes of cirrhotic sinusoids by serial histological sections. METHODS Cirrhosis was induced by tail vein injection of albumin in Wistar rats with a positive antibody. A total of 356 serial histological sections were prepared from liver tissue blocks of normal and cirrhotic rats. The optical microscope images were registered and reconstructed, and 3D reconstructions of the fine structures of fibrous tissues and sinusoids were subsequently visualized. RESULTS The fibrosis area of the cirrhotic sample was 6-16 times that of the normal sample (P<0.001). Cirrhosis led to obvious changes in the distribution and morphology of sinusoids, which were mainly manifested as dilation, increased quantity and disordered distribution. Compared with normal liver, cirrhotic liver has a significantly increased volume ratio, number and volume of sinusoids (1.63-, 0.53-, and 1.75-fold, respectively, P<0.001). Furthermore, the samples were further divided into three zones according to the oxygen supply, and there were significant differences in the morphology of the sinusoids in the normal and cirrhotic samples (P<0.05). In particular, morphological parameters of the cirrhotic sinusoids near the portal area were obviously greater than those in the normal liver (P<0.05). CONCLUSION 3D morphological structures of hepatic sinusoids were reconstructed, and the adaptive microstructure changes of cirrhotic sinusoids were accurately measured, which has an important implications for the study of hepatic microcirculation and pathological changes of cirrhosis.
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Affiliation(s)
- Jing-Yi Liu
- School of Biomedical Engineering and Technology, Tianjin Medical University, Tianjin, China
| | - Wen-Juan Lv
- School of Biomedical Engineering and Technology, Tianjin Medical University, Tianjin, China
| | - Jian-Bo Jian
- Department of Radiation Oncology, Tianjin Medical University General Hospital, Tianjin, China, China
| | - Xiao-Hong Xin
- School of Biomedical Engineering and Technology, Tianjin Medical University, Tianjin, China
| | - Xin-Yan Zhao
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China. .,Beijing Key Laboratory of Translational Medicine in Liver Cirrhosis and National Clinical Research Center of Digestive Disease, Beijing, China
| | - Chun-Hong Hu
- School of Biomedical Engineering and Technology, Tianjin Medical University, Tianjin, China.
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9
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Wagner WL, Föhst S, Hock J, Kim YO, Popov Y, Schuppan D, Schladitz K, Redenbach C, Ackermann M. 3D analysis of microvasculature in murine liver fibrosis models using synchrotron radiation-based microtomography. Angiogenesis 2021; 24:57-65. [PMID: 33037487 PMCID: PMC7920893 DOI: 10.1007/s10456-020-09751-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/28/2020] [Indexed: 12/16/2022]
Abstract
Cirrhosis describes the development of excess fibrous tissue around regenerative nodules in response to chronic liver injury and usually leads to irreversible organ damage and end-stage liver disease. During the development of cirrhosis, the formation of collagenous scar tissue is paralleled by a reorganization and remodeling of the hepatic vascular system. To date, macrovascular remodeling in various cirrhosis models has been examined using three-dimensional (3D) imaging modalities, while microvascular changes have been studied mainly by two-dimensional (2D) light microscopic and electron microscopic imaging. Here, we report on the application of high-resolution 3D synchrotron radiation-based microtomography (SRμCT) for the study of the sinusoidal and capillary blood vessel system in three murine models of advanced parenchymal and biliary hepatic fibrosis. SRμCT facilitates the characterization of microvascular architecture and identifies features of intussusceptive angiogenesis in progressive liver fibrosis in a non-destructive 3D manner.
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Affiliation(s)
- Willi L Wagner
- Department of Diagnostic and Interventional Radiology, University of Heidelberg, Heidelberg, Germany
- Translational Lung Research Center, Member of the German Center for Lung Research, University of Heidelberg, Heidelberg, Germany
| | - Sonja Föhst
- Mathematics Department, Technische Universität Kaiserslautern, Kaiserslautern, Germany
| | - Jessica Hock
- Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg-University Mainz, Johann-Joachim-Becher-Weg 13, 55128, Mainz, Germany
| | - Yong Ook Kim
- Institute of Translational Immunology and Research Center for Immune Therapy (FZI), University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Yury Popov
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Detlef Schuppan
- Institute of Translational Immunology and Research Center for Immune Therapy (FZI), University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Katja Schladitz
- Image Processing Department, Fraunhofer ITWM, Kaiserslautern, Germany
| | - Claudia Redenbach
- Mathematics Department, Technische Universität Kaiserslautern, Kaiserslautern, Germany
| | - Maximilian Ackermann
- Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg-University Mainz, Johann-Joachim-Becher-Weg 13, 55128, Mainz, Germany.
- Institute of Pathology and Molecular Pathology, Helios University Clinic Wuppertal, University of Witten-Herdecke, Wuppertal, Germany.
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10
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Shin SK, Kaiser EE, West FD. Alcohol Induced Brain and Liver Damage: Advantages of a Porcine Alcohol Use Disorder Model. Front Physiol 2021; 11:592950. [PMID: 33488396 PMCID: PMC7818780 DOI: 10.3389/fphys.2020.592950] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 12/01/2020] [Indexed: 12/30/2022] Open
Abstract
Alcohol is one of the most commonly abused intoxicants with 1 in 6 adults at risk for alcohol use disorder (AUD) in the United States. As such, animal models have been extensively investigated with rodent AUD models being the most widely studied. However, inherent anatomical and physiological differences between rodents and humans pose a number of limitations in studying the complex nature of human AUD. For example, rodents differ from humans in that rodents metabolize alcohol rapidly and do not innately demonstrate voluntary alcohol consumption. Comparatively, pigs exhibit similar patterns observed in human AUD including voluntary alcohol consumption and intoxication behaviors, which are instrumental in establishing a more representative AUD model that could in turn delineate the risk factors involved in the development of this disorder. Pigs and humans also share anatomical similarities in the two major target organs of alcohol- the brain and liver. Pigs possess gyrencephalic brains with comparable cerebral white matter volumes to humans, thus enabling more representative evaluations of susceptibility and neural tissue damage in response to AUD. Furthermore, similarities in the liver result in a comparable rate of alcohol elimination as humans, thus enabling a more accurate extrapolation of dosage and intoxication level to humans. A porcine model of AUD possesses great translational potential that can significantly advance our current understanding of the complex development and continuance of AUD in humans.
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Affiliation(s)
- Soo K Shin
- Regenerative Bioscience Center, University of Georgia, Athens, GA, United States.,Interdisciplinary Toxicology Program, University of Georgia, Athens, GA, United States.,Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, United States
| | - Erin E Kaiser
- Regenerative Bioscience Center, University of Georgia, Athens, GA, United States.,Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, United States.,Neuroscience Program, Biomedical and Health Sciences Institute, University of Georgia, Athens, GA, United States
| | - Franklin D West
- Regenerative Bioscience Center, University of Georgia, Athens, GA, United States.,Interdisciplinary Toxicology Program, University of Georgia, Athens, GA, United States.,Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, United States.,Neuroscience Program, Biomedical and Health Sciences Institute, University of Georgia, Athens, GA, United States
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11
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Shi D, Kiefer RM, Nishiofuku H, Cortes A, Nadolski GJ, Hunt SJ, Avritscher R, Gade TPF. Angiographic Atlas of the Visceral Vascular Anatomy in Translational Rat Models. J Vasc Interv Radiol 2019; 30:2009-2015.e1. [PMID: 31202678 DOI: 10.1016/j.jvir.2019.03.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 03/06/2019] [Accepted: 03/06/2019] [Indexed: 02/08/2023] Open
Abstract
PURPOSE To characterize angiographic and cross-sectional imaging anatomy of the rat visceral vasculature in 2 translational models. MATERIALS AND METHODS Animal studies were conducted in accordance with institutional guidelines and approval of the Institutional Animal Care and Use Committees. Retrospective review of digital subtraction arteriography was performed in 65 Wistar and 50 Sprague-Dawley male rats through a left common carotid artery or right common femoral artery approach. MR imaging of the abdomen was performed on the rats to correlate imaging modalities. RESULTS Aortography was performed in 3 locations, including cranial to the celiac artery, cranial to the renal arteries, and cranial to the caudal (inferior) mesenteric artery, enabling characterization of the visceral branch arteries in all 65 Wistar rats. Selective arteriography of first-, second-, and third-order branch vessels of the aorta was performed allowing characterization of normal and variant anatomy. Dedicated selective arteriography was performed of the celiac artery in 65 Wistar and 10 Sprague-Dawley rats, of the common hepatic artery in 65 Wistar and 50 Sprague-Dawley rats, and of the cranial mesenteric artery in 43 Wistar rats. MR imaging enabled correlation with the lobar and portal venous anatomy. CONCLUSIONS Analysis of arteriography and MR imaging in these rat models will provide translational researchers with anatomic details needed to develop new endovascular protocols for small animal research in interventional radiology.
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Affiliation(s)
- Donghua Shi
- Penn Image-Guided Interventions Laboratory, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania; Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ryan M Kiefer
- Penn Image-Guided Interventions Laboratory, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania; Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Hideyuki Nishiofuku
- Department of Radiology and IVR Center, Nara Medical University, Kashihara-city, Nara, Japan
| | - Andrea Cortes
- Department of Interventional Radiology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Gregory J Nadolski
- Penn Image-Guided Interventions Laboratory, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania; Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Stephen J Hunt
- Penn Image-Guided Interventions Laboratory, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania; Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Rony Avritscher
- Department of Interventional Radiology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Terence P F Gade
- Penn Image-Guided Interventions Laboratory, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania; Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania; Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
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12
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Mosharaf-Dehkordi M. A fully coupled porous media and channels flow approach for simulation of blood and bile flow through the liver lobules. Comput Methods Biomech Biomed Engin 2019; 22:901-915. [PMID: 31124725 DOI: 10.1080/10255842.2019.1601180] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Two dimensional, steady state, and incompressible blood and bile flows through the liver lobules are numerically simulated. Two different geometric models A and B are proposed to study the effects of lobule structure on the fluid flow behaviour. In Model A, the lobule tissue is represented as a hexagonal shape porous medium with a set of flow channels at its vertices accounting for the hepatic artery, portal and central veins along with bile ductules. Model B is a channelized porous medium constructed by adding a set of flow channels, representing the bile canaliculies and lobule sinusoids, to Model A. The bile and blood flow through the lobule is simulated by the finite element approach, based on the Darcy/Brinkman equations in the lobule tissue and the Navier-Stokes (or Stokes) equations in the flow channels. In Model B, a transmission factor on the boundaries of the bile canaliculies is introduced to connect the bile and blood flows. First, a single regular lobule is utilized to exhibit the fluid flow pattern through the liver lobule represented by proposed geometric models. Then, the model is extended to a group of liver lobules to demonstrate the flow through a liver slice represented by irregular lobules. Numerical results indicate that the Darcy and Brinkman equations provide nearly the same solutions for Model A and similar solutions with a little difference for Model B. It is shown that the existence of sinusoids and bile canaliculies inside the liver lobules has noticeable effects on its fluid flow pattern, in terms of pressure and velocity fields.
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Affiliation(s)
- Mehdi Mosharaf-Dehkordi
- a Department of Mechanical Engineering, Faculty of Engineering , University of Isfahan , Isfahan , Iran
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13
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Kruepunga N, Hakvoort TB, Hikspoors JP, Köhler SE, Lamers WH. Anatomy of rodent and human livers: What are the differences? Biochim Biophys Acta Mol Basis Dis 2019; 1865:869-878. [DOI: 10.1016/j.bbadis.2018.05.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/30/2018] [Accepted: 05/22/2018] [Indexed: 12/17/2022]
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14
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Bezborodkina NN, Chestnova AY, Vorobev ML, Kudryavtsev BN. Spatial Structure of Glycogen Molecules in Cells. BIOCHEMISTRY (MOSCOW) 2018; 83:467-482. [PMID: 29738682 DOI: 10.1134/s0006297918050012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Glycogen is a strongly branched polymer of α-D-glucose, with glucose residues in the linear chains linked by 1→4-bonds (~93% of the total number of bonds) and with branching after every 4-8 residues formed by 1→6-glycosidic bonds (~7% of the total number of bonds). It is thought currently that a fully formed glycogen molecule (β-particle) with the self-glycosylating protein glycogenin in the center has a spherical shape with diameter of ~42 nm and contains ~ 55,000 glucose residues. The glycogen molecule also includes numerous proteins involved in its synthesis and degradation, as well as proteins performing a carcass function. However, the type and force of bonds connecting these proteins to the polysaccharide moiety of glycogen are significantly different. This review presents the available data on the spatial structure of the glycogen molecule and its changes under various physiological and pathological conditions.
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Affiliation(s)
- N N Bezborodkina
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia.
| | - A Yu Chestnova
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia
| | - M L Vorobev
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia
| | - B N Kudryavtsev
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia
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15
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Microcirculation in the murine liver: a computational fluid dynamic model based on 3D reconstruction from in vivo microscopy. J Biomech 2017; 63:125-134. [PMID: 28917579 DOI: 10.1016/j.jbiomech.2017.08.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 06/28/2017] [Accepted: 08/11/2017] [Indexed: 02/07/2023]
Abstract
The liver is organized in hexagonal functional units - termed lobules - characterized by a rather peculiar blood microcirculation, due to the presence of a tangled network of capillaries - termed sinusoids. A better understanding of the hemodynamics that governs liver microcirculation is relevant to clinical and biological studies aimed at improving our management of liver diseases and transplantation. Herein, we built a CFD model of a 3D sinusoidal network, based on in vivo images of a physiological mouse liver obtained with a 2-photon microscope. The CFD model was developed with Fluent 16.0 (ANSYS Inc., Canonsburg, PA), particular care was taken in imposing the correct boundary conditions representing a physiological state. To account for the remaining branches of the sinusoids, a lumped parameter model was used to prescribe the correct pressure at each outlet. The effect of an adhered cell on local hemodynamics is also investigated for different occlusion degrees. The model here proposed accurately reproduces the fluid dynamics in a portion of the sinusoidal network in mouse liver. Mean velocities and mass flow rates are in agreement with literature values from in vivo measurements. Our approach provides details on local phenomena, hardly described by other computational studies, either focused on the macroscopic hepatic vasculature or based on homogeneous porous medium model.
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16
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Irwin RD, Boorman GA, Cunningham ML, Heinloth AN, Malarkey DE, Paules RS. Application of Toxicogenomics to Toxicology: Basic Concepts in the Analysis of Microarray Data. Toxicol Pathol 2016; 32 Suppl 1:72-83. [PMID: 15209406 DOI: 10.1080/01926230490424752] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Toxicology and the practice of pathology are rapidly evolving in the postgenomic era. Observable treatment related changes have been the hallmark of toxicology studies. Toxicogenomics is a powerful new tool that may show gene and protein changes earlier and at treatment levels below the limits of detection of traditional measures of toxicity. It may also aid in the understanding of toxic mechanisms. It is important to remember that it is only a tool and will provide meaningful results only when properly applied. As is often the case with new experimental tools, the initial utilization is driven more by the technology than application to problem solving. Toxicogenomics is interdisciplinary in nature including at a minimum, pathology, toxicology, and genomics. Most studies will require the input from the disciplines of toxicology, pathology, molecular biology, bioinformatics, biochemistry, and others depending on the types of questions being asked.
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Affiliation(s)
- Richard D Irwin
- Environmental Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA.
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17
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Schwen LO, Homeyer A, Schwier M, Dahmen U, Dirsch O, Schenk A, Kuepfer L, Preusser T, Schenk A. Zonated quantification of steatosis in an entire mouse liver. Comput Biol Med 2016; 73:108-18. [PMID: 27104496 DOI: 10.1016/j.compbiomed.2016.04.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 04/06/2016] [Accepted: 04/09/2016] [Indexed: 12/16/2022]
Abstract
Many physiological processes and pathological conditions in livers are spatially heterogeneous, forming patterns at the lobular length scale or varying across the organ. Steatosis, a common liver disease characterized by lipids accumulating in hepatocytes, exhibits heterogeneity at both these spatial scales. The main goal of the present study was to provide a method for zonated quantification of the steatosis patterns found in an entire mouse liver. As an example application, the results were employed in a pharmacokinetics simulation. For the analysis, an automatic detection of the lipid vacuoles was used in multiple slides of histological serial sections covering an entire mouse liver. Lobuli were determined semi-automatically and zones were defined within the lobuli. Subsequently, the lipid content of each zone was computed. The steatosis patterns were found to be predominantly periportal, with a notable organ-scale heterogeneity. The analysis provides a quantitative description of the extent of steatosis in unprecedented detail. The resulting steatosis patterns were successfully used as a perturbation to the liver as part of an exemplary whole-body pharmacokinetics simulation for the antitussive drug dextromethorphan. The zonated quantification is also applicable to other pathological conditions that can be detected in histological images. Besides being a descriptive research tool, this quantification could perspectively complement diagnosis based on visual assessment of histological images.
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Affiliation(s)
- Lars Ole Schwen
- Fraunhofer MEVIS, Universitätsallee 29, 28359 Bremen, Germany.
| | - André Homeyer
- Fraunhofer MEVIS, Universitätsallee 29, 28359 Bremen, Germany.
| | - Michael Schwier
- Fraunhofer MEVIS, Universitätsallee 29, 28359 Bremen, Germany; Jacobs University, Campus Ring 1, 28759 Bremen, Germany.
| | - Uta Dahmen
- Experimental Transplantation Surgery, Department of General, Visceral and Vascular Surgery, University Hospital Jena, Drackendorfer Str. 1, 07747 Jena, Germany.
| | - Olaf Dirsch
- Institute of Pathology, Klinikum Chemitz, Flemmingstraße 2, 09116 Chemnitz, Germany.
| | - Arne Schenk
- Computational Systems Biology, Bayer Technology Services, Kaiser-Wilhelm-Allee 1, 51368 Leverkusen, Germany; Aachen Institute for Advanced Study in Computational Engineering Sciences, RWTH Aachen University, Schinkelstr. 2, 52062 Aachen, Germany.
| | - Lars Kuepfer
- Computational Systems Biology, Bayer Technology Services, Kaiser-Wilhelm-Allee 1, 51368 Leverkusen, Germany; Institute of Applied Microbiology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.
| | - Tobias Preusser
- Fraunhofer MEVIS, Universitätsallee 29, 28359 Bremen, Germany; Jacobs University, Campus Ring 1, 28759 Bremen, Germany.
| | - Andrea Schenk
- Fraunhofer MEVIS, Universitätsallee 29, 28359 Bremen, Germany.
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18
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Marcos R, Lopes C, Malhão F, Correia-Gomes C, Fonseca S, Lima M, Gebhardt R, Rocha E. Stereological assessment of sexual dimorphism in the rat liver reveals differences in hepatocytes and Kupffer cells but not hepatic stellate cells. J Anat 2016; 228:996-1005. [PMID: 26892301 DOI: 10.1111/joa.12448] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2016] [Indexed: 12/11/2022] Open
Abstract
There is long-standing evidence that male and female rat livers differ in enzyme activity. More recently, differences in gene expression profiling have also been found to exist; however, it is still unclear whether there is morphological expression of male/female differences in the normal liver. Such differences could help to explain features seen at the pathological level, such as the greater regenerative potential generally attributed to the female liver. In this paper, hepatocytes (HEP), Kupffer cells (KC) and hepatic stellate cells (HSC) of male and female rats were examined to investigate hypothesised differences in number, volume and spatial co-localisation of these cell types. Immunohistochemistry and design-based stereology were used to estimate total numbers, numbers per gram and mean cell volumes. The position of HSC within lobules (periportal vs. centrilobular) and their spatial proximity to KC was also assessed. In addition, flow cytometry was used to investigate the liver ploidy. In the case of HEP and KC, differences in the measured cell parameters were observed between male and female specimens; however, no such differences were detected for HSC. Female samples contained a higher number of HEP per gram, with more binucleate cells. The HEP nuclei were smaller in females, which was coincident with more abundant diploid particles in these animals. The female liver also had a greater number of KC per gram, with a lower percentage of KC in the vicinity of HSC compared with males. In this study, we document hitherto unknown morphological sexual dimorphism in the rat liver, namely in HEP and KC. These differences may account for the higher regenerative potential of the female liver and lend weight to the argument for considering the rat liver as a sexually dimorphic organ.
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Affiliation(s)
- Ricardo Marcos
- Laboratory of Histology and Embryology, Department of Microscopy, ICBAS - Institute of Biomedical Sciences Abel Salazar, U.Porto - University of Porto, Porto, Portugal.,Histomorphology, Physiopathology and Applied Toxicology Group, CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, U.Porto - University of Porto, Porto, Portugal
| | - Célia Lopes
- Laboratory of Histology and Embryology, Department of Microscopy, ICBAS - Institute of Biomedical Sciences Abel Salazar, U.Porto - University of Porto, Porto, Portugal.,Histomorphology, Physiopathology and Applied Toxicology Group, CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, U.Porto - University of Porto, Porto, Portugal
| | - Fernanda Malhão
- Laboratory of Histology and Embryology, Department of Microscopy, ICBAS - Institute of Biomedical Sciences Abel Salazar, U.Porto - University of Porto, Porto, Portugal.,Histomorphology, Physiopathology and Applied Toxicology Group, CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, U.Porto - University of Porto, Porto, Portugal
| | - Carla Correia-Gomes
- Scotland's Rural College, Epidemiology Research Unit - Future Farming Systems Group, Inverness, UK
| | - Sónia Fonseca
- Laboratory of Cytometry, Department of Hematology, UMIB - Unit for Multidisciplinary Research in Biomedicine, CHP - Centro Hospitalar do Porto, ICBAS - Institute of Biomedical Sciences Abel Salazar, HSA - Hospital de Santo António, U.Porto - University of Porto, Porto, Portugal
| | - Margarida Lima
- Laboratory of Cytometry, Department of Hematology, UMIB - Unit for Multidisciplinary Research in Biomedicine, CHP - Centro Hospitalar do Porto, ICBAS - Institute of Biomedical Sciences Abel Salazar, HSA - Hospital de Santo António, U.Porto - University of Porto, Porto, Portugal
| | - Rolf Gebhardt
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Eduardo Rocha
- Laboratory of Histology and Embryology, Department of Microscopy, ICBAS - Institute of Biomedical Sciences Abel Salazar, U.Porto - University of Porto, Porto, Portugal.,Histomorphology, Physiopathology and Applied Toxicology Group, CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, U.Porto - University of Porto, Porto, Portugal
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19
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Böser P, Mordashova Y, Maasland M, Trommer I, Lorenz H, Hafner M, Seemann D, Mueller BK, Popp A. Quantification of Hepcidin-related Iron Accumulation in the Rat Liver. Toxicol Pathol 2016; 44:259-66. [PMID: 26839325 DOI: 10.1177/0192623315623866] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Hepcidin was originally detected as a liver peptide with antimicrobial activity and it functions as a central regulator in the systemic iron metabolism. Consequently suppression of hepcidin leads to iron accumulation in the liver. AbbVie developed a monoclonal antibody ([mAb]; repulsive guidance molecule [RGMa/c] mAb) that downregulates hepcidin expression by influencing the RGMc/bone morphogenetic protein (BMP)/neogenin receptor complex and causes iron deposition in the liver. In a dose range finding study with RGMa/c mAb, rats were treated with different dose levels for a total of 4 weekly doses. The results of this morphometric analysis in the liver showed that iron accumulation is not homogenous between liver lobes and the left lateral lobe was the most responsive lobe in the rat. Quantitative hepcidin messenger RNA analysis showed that the left lateral lobe was the most responsive lobe showing hepcidin downregulation with increasing antibody dose. In addition, the morphometric analysis had higher sensitivity than the chemical iron extraction and quantification using a colorimetric assay. In conclusion, the Prussian blue stain in combination with semi-quantitative and quantitative morphometric analysis is the most reliable method to demonstrate iron accumulation in the liver compared to direct measurement of iron in unfixed tissue using a colorimetric assay.
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Affiliation(s)
- Preethne Böser
- AbbVie Deutschland GmbH & Co. KG, Ludwigshafen, Germany Institute for Medical Technology, Heidelberg University and University of Applied Sciences Mannheim, Ludwigshafen, Germany
| | | | - Mark Maasland
- Fraunhofer Institute for Industrial Mathematics ITWM, Kaiserslautern, Ludwigshafen, Germany
| | | | - Helga Lorenz
- AbbVie Deutschland GmbH & Co. KG, Ludwigshafen, Germany
| | - Mathias Hafner
- Institute for Medical Technology, Heidelberg University and University of Applied Sciences Mannheim, Ludwigshafen, Germany
| | | | | | - Andreas Popp
- AbbVie Deutschland GmbH & Co. KG, Ludwigshafen, Germany
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20
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Bezborodkina NN, Chestnova AY, Vorobev ML, Kudryavtsev BN. Glycogen content in hepatocytes is related with their size in normal rat liver but not in cirrhotic one. Cytometry A 2016; 89:357-64. [PMID: 26785401 DOI: 10.1002/cyto.a.22811] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 11/27/2015] [Accepted: 12/10/2015] [Indexed: 12/16/2022]
Abstract
BACKGROUND & AIMS Hepatocytes differ from one another by the degree of the ploidy, size, position in the liver lobule, and level of the DNA-synthetic processes. It is believed, that the cell size exerts substantial influence on the metabolism of the hepatocytes and the glycogen content in them. The aim of the present study was to test this hypothesis. METHODS Dry weight of hepatocytes, their ploidy and glycogen content were determined in the normal and the cirrhotic rat liver. Liver cirrhosis in rats was produced by chronic inhalation of CCl4 vapours in the course of 6 months. A combined cytophotometric method was used. Dry weight of the cell, its glycogen and DNA content were successively measured on a mapped preparation. RESULT Hepatocytes of each ploidy class in the normal and the cirrhotic rat liver accumulated glycogen at the same rate. In the normal liver, there was a distinct correlation between the size of hepatocytes and glycogen content in them. This correlation was observed in each ploidy class, and was especially pronounced in the class of mononucleate tetraploid hepatocytes. In the cirrhotic liver, there was no correlation between the size of the cells and their glycogen content. CONCLUSIONS The impairment of liver lobular structure probably explains the observed lack of correlation between hepatocyte size and their glycogen content in the cirrhotic liver. © 2016 International Society for Advancement of Cytometry.
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Affiliation(s)
- Natalia N Bezborodkina
- Laboratory of Cellular Pathology, Institute of Cytology of the Russian Academy of Sciences, Saint Petersburg, Russia
| | - Anna Yu Chestnova
- Laboratory of Cellular Pathology, Institute of Cytology of the Russian Academy of Sciences, Saint Petersburg, Russia
| | - Mikhail L Vorobev
- Laboratory of Cellular Pathology, Institute of Cytology of the Russian Academy of Sciences, Saint Petersburg, Russia
| | - Boris N Kudryavtsev
- Laboratory of Cellular Pathology, Institute of Cytology of the Russian Academy of Sciences, Saint Petersburg, Russia
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Schwen LO, Schenk A, Kreutz C, Timmer J, Bartolomé Rodríguez MM, Kuepfer L, Preusser T. Representative Sinusoids for Hepatic Four-Scale Pharmacokinetics Simulations. PLoS One 2015. [PMID: 26222615 PMCID: PMC4519332 DOI: 10.1371/journal.pone.0133653] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The mammalian liver plays a key role for metabolism and detoxification of xenobiotics in the body. The corresponding biochemical processes are typically subject to spatial variations at different length scales. Zonal enzyme expression along sinusoids leads to zonated metabolization already in the healthy state. Pathological states of the liver may involve liver cells affected in a zonated manner or heterogeneously across the whole organ. This spatial heterogeneity, however, cannot be described by most computational models which usually consider the liver as a homogeneous, well-stirred organ. The goal of this article is to present a methodology to extend whole-body pharmacokinetics models by a detailed liver model, combining different modeling approaches from the literature. This approach results in an integrated four-scale model, from single cells via sinusoids and the organ to the whole organism, capable of mechanistically representing metabolization inhomogeneity in livers at different spatial scales. Moreover, the model shows circulatory mixing effects due to a delayed recirculation through the surrounding organism. To show that this approach is generally applicable for different physiological processes, we show three applications as proofs of concept, covering a range of species, compounds, and diseased states: clearance of midazolam in steatotic human livers, clearance of caffeine in mouse livers regenerating from necrosis, and a parameter study on the impact of different cell entities on insulin uptake in mouse livers. The examples illustrate how variations only discernible at the local scale influence substance distribution in the plasma at the whole-body level. In particular, our results show that simultaneously considering variations at all relevant spatial scales may be necessary to understand their impact on observations at the organism scale.
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Affiliation(s)
| | - Arne Schenk
- Computational Systems Biology, Bayer Technology Services, Leverkusen, Germany
- Aachen Institute for Advanced Study in Computational Engineering Sciences, RWTH Aachen University, Aachen, Germany
| | - Clemens Kreutz
- Freiburg Center for Data Analysis and Modeling (FDM), Institute of Physics, University of Freiburg, Freiburg, Germany
| | - Jens Timmer
- Freiburg Center for Data Analysis and Modeling (FDM), Institute of Physics, University of Freiburg, Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | | | - Lars Kuepfer
- Computational Systems Biology, Bayer Technology Services, Leverkusen, Germany
- Institute of Applied Microbiology, RWTH Aachen University, Aachen, Germany
| | - Tobias Preusser
- Fraunhofer MEVIS, Bremen, Germany
- Jacobs University, Bremen, Germany
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Modeling function–perfusion behavior in liver lobules including tissue, blood, glucose, lactate and glycogen by use of a coupled two-scale PDE–ODE approach. Biomech Model Mechanobiol 2014; 14:515-36. [DOI: 10.1007/s10237-014-0619-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 09/02/2014] [Indexed: 01/22/2023]
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23
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Björnmalm M, Yan Y, Caruso F. Engineering and evaluating drug delivery particles in microfluidic devices. J Control Release 2014; 190:139-49. [DOI: 10.1016/j.jconrel.2014.04.030] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 03/14/2014] [Accepted: 03/21/2014] [Indexed: 02/03/2023]
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Wang Y, Xu R, Luo G, Wu J. Three-dimensional reconstruction of light microscopy image sections: present and future. Front Med 2014; 9:30-45. [DOI: 10.1007/s11684-014-0337-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 03/27/2014] [Indexed: 12/31/2022]
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25
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Lobe-specific heterogeneity in asymmetric dimethylarginine and matrix metalloproteinase levels in a rat model of obstructive cholestasis. BIOMED RESEARCH INTERNATIONAL 2014; 2014:327537. [PMID: 25013773 PMCID: PMC4075188 DOI: 10.1155/2014/327537] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/23/2014] [Accepted: 05/26/2014] [Indexed: 12/14/2022]
Abstract
We investigated the effects of obstructive cholestasis in different hepatic lobes by evaluating asymmetric dimethylarginine (ADMA) (a nitric oxide synthase inhibitor), protein methyltransferase (PRMT) and dimethylarginine dimethylaminohydrolase (DDAH) (enzymes involved, resp., in its synthesis and degradation), the cationic transporter (CAT), and metalloproteinase (MMP) activity. Sixteen male Wistar rats underwent a 3-day cholestasis by common bile duct ligation (BDL) or sham operation. Blood samples and hepatic biopsies from left lobe (LL), median lobe (ML), and right lobe (RL) were collected. Serum hepatic enzymes, tissue ADMA, DDAH activity, CAT-2 protein, mRNA expression of DDAH and PRMT, and MMP-2 and MMP-9 activity were monitored. Cholestasis was confirmed by altered serum hepatic enzymes. Higher levels of tissue ADMA were detected in RL and ML as compared with LL. PRMT mRNA expression and DDAH activity did not differ among the lobes after BDL. CAT-2 levels are higher in the RL and ML in the sham-operated group. Higher activity in MMP-2 and MMP-9 was found in RL. In conclusion, after cholestasis an increase in hepatic ADMA in RL and ML was detected as well as tissue MMP-2 and MMP-9 activation in RL, supporting the evidence of functional heterogeneity among the liver lobes also occurring in an obstructive cholestasis model.
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Debbaut C, Segers P, Cornillie P, Casteleyn C, Dierick M, Laleman W, Monbaliu D. Analyzing the human liver vascular architecture by combining vascular corrosion casting and micro-CT scanning: a feasibility study. J Anat 2014; 224:509-17. [PMID: 24433401 DOI: 10.1111/joa.12156] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/07/2013] [Indexed: 11/26/2022] Open
Abstract
Although a full understanding of the hepatic circulation is one of the keys to successfully perform liver surgery and to elucidate liver pathology, relatively little is known about the functional organization of the liver vasculature. Therefore, we materialized and visualized the human hepatic vasculature at different scales, and performed a morphological analysis by combining vascular corrosion casting with novel micro-computer tomography (CT) and image analysis techniques. A human liver vascular corrosion cast was obtained by simultaneous resin injection in the hepatic artery (HA) and portal vein (PV). A high resolution (110 μm) micro-CT scan of the total cast allowed gathering detailed macrovascular data. Subsequently, a mesocirculation sample (starting at generation 5; 88 × 68 × 80 mm³) and a microcirculation sample (terminal vessels including sinusoids; 2.0 × 1.5 × 1.7 mm³) were dissected and imaged at a 71-μm and 2.6-μm resolution, respectively. Segmentations and 3D reconstructions allowed quantifying the macro- and mesoscale branching topology, and geometrical features of HA, PV and hepatic venous trees up to 13 generations (radii ranging from 13.2 mm to 80 μm; lengths from 74.4 mm to 0.74 mm), as well as microvascular characteristics (mean sinusoidal radius of 6.63 μm). Combining corrosion casting and micro-CT imaging allows quantifying the branching topology and geometrical features of hepatic trees using a multiscale approach from the macro- down to the microcirculation. This may lead to novel insights into liver circulation, such as internal blood flow distributions and anatomical consequences of pathologies (e.g. cirrhosis).
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Affiliation(s)
- Charlotte Debbaut
- Biofluid, Tissue and Solid Mechanics for Medical Applications, Institute Biomedical Technology, Department of Electronics and Information Systems, iMinds Future Health Department, Ghent University, Gent, Belgium
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27
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Rezania V, Marsh R, Coombe D, Tuszynski J. A physiologically-based flow network model for hepatic drug elimination I: regular lattice lobule model. Theor Biol Med Model 2013; 10:52. [PMID: 24007328 PMCID: PMC3849449 DOI: 10.1186/1742-4682-10-52] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 08/22/2013] [Indexed: 12/22/2022] Open
Abstract
We develop a physiologically-based lattice model for the transport and metabolism of drugs in the functional unit of the liver, called the lobule. In contrast to earlier studies, we have emphasized the dominant role of convection in well-vascularized tissue with a given structure. Estimates of convective, diffusive and reaction contributions are given. We have compared drug concentration levels observed exiting the lobule with their predicted detailed distribution inside the lobule, assuming that most often the former is accessible information while the latter is not.
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Affiliation(s)
- Vahid Rezania
- Department of Physics, University of Alberta, Edmonton, AB T6G 2J1, Canada.
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Siggers JH, Leungchavaphongse K, Ho CH, Repetto R. Mathematical model of blood and interstitial flow and lymph production in the liver. Biomech Model Mechanobiol 2013; 13:363-78. [PMID: 23907149 PMCID: PMC3968522 DOI: 10.1007/s10237-013-0516-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 07/17/2013] [Indexed: 01/10/2023]
Abstract
We present a mathematical model of blood and interstitial flow in the liver. The liver is treated as a lattice of hexagonal ‘classic’ lobules, which are assumed to be long enough that end effects may be neglected and a two-dimensional problem considered. Since sinusoids and lymphatic vessels are numerous and small compared to the lobule, we use a homogenized approach, describing the sinusoidal and interstitial spaces as porous media. We model plasma filtration from sinusoids to the interstitium, lymph uptake by lymphatic ducts, and lymph outflow from the liver surface. Our results show that the effect of the liver surface only penetrates a depth of a few lobules’ thickness into the tissue. Thus, we separately consider a single lobule lying sufficiently far from all external boundaries that we may regard it as being in an infinite lattice, and also a model of the region near the liver surface. The model predicts that slightly more lymph is produced by interstitial fluid flowing through the liver surface than that taken up by the lymphatic vessels in the liver and that the non-peritonealized region of the surface of the liver results in the total lymph production (uptake by lymphatics plus fluid crossing surface) being about 5 % more than if the entire surface were covered by the Glisson–peritoneal membrane. Estimates of lymph outflow through the surface of the liver are in good agreement with experimental data. We also study the effect of non-physiological values of the controlling parameters, particularly focusing on the conditions of portal hypertension and ascites. To our knowledge, this is the first attempt to model lymph production in the liver. The model provides clinically relevant information about lymph outflow pathways and predicts the systemic response to pathological variations.
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Affiliation(s)
- Jennifer H Siggers
- Department of Bioengineering, Imperial College London, London, SW7 2AZ, UK,
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Three-dimensional imaging of hepatic sinusoids in mice using synchrotron radiation micro-computed tomography. PLoS One 2013; 8:e68600. [PMID: 23861925 PMCID: PMC3702620 DOI: 10.1371/journal.pone.0068600] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Accepted: 05/31/2013] [Indexed: 12/20/2022] Open
Abstract
Hepatic sinusoid, the smallest vessel in the liver, plays important roles in hepatic microcirculation. Although the structure of the hepatic sinusoids affects diverse functions of the liver, little is known about morphological alterations in the sinusoids under pathological conditions. In this study, we show that the structure of hepatic sinusoids can be identified three-dimensionally in normal and carbon tetrachloride-injured mouse liver, using the absorption mode of synchrotron radiation micro-computed tomography. We observed that the hepatic sinusoidal structure on tomographic slice images was similar to that on histological images of normal and acutely injured mice. Moreover, centrilobular necrosis and structural alterations of the sinusoids in the necrotic region were detectable on tomographic slice and volume-rendered images of the acutely injured mice. Furthermore, quantitative analyses on 3D volume-rendered images of the injured sinusoid revealed decrease in the volume of the sinusoid and connectivity of the sinusoidal network. Our results suggest that the use of synchrotron radiation micro-computed tomography may improve our understanding of the pathogenesis of hepatic diseases by detecting the hepatic sinusoids and their alterations in three-dimensional structures of the damaged liver.
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Abstract
This unique overview of systems toxicology methods and techniques begins with a brief account of systems thinking in biology over the last century. We discuss how systems biology and toxicology continue to leverage advances in computational modeling, informatics, large-scale computing, and biotechnology. Next, we chart the genesis of systems toxicology from previous work in physiologically based models, models of early development, and more recently, molecular systems biology. For readers interested in further details this background provides useful linkages to the relevant literature. It also lays the foundations for new ideas in systems toxicology that could translate laboratory measurements of molecular responses from xenobiotic perturbations to adverse organ level effects in humans. By providing innovative solutions across disciplinary boundaries and highlighting key scientific gaps, we believe this chapter provides useful information about the current state, and valuable insight about future directions in systems toxicity.
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Debbaut C, Vierendeels J, Siggers JH, Repetto R, Monbaliu D, Segers P. A 3D porous media liver lobule model: the importance of vascular septa and anisotropic permeability for homogeneous perfusion. Comput Methods Biomech Biomed Engin 2012; 17:1295-310. [PMID: 23237543 DOI: 10.1080/10255842.2012.744399] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The hepatic blood circulation is complex, particularly at the microcirculatory level. Previously, 2D liver lobule models using porous media and a 3D model using real sinusoidal geometries have been developed. We extended these models to investigate the role of vascular septa (VS) and anisotropic permeability. The lobule was modelled as a hexagonal prism (with or without VS) and the tissue was treated as a porous medium (isotropic or anisotropic permeability). Models were solved using computational fluid dynamics. VS inclusion resulted in more spatially homogeneous perfusion. Anisotropic permeability resulted in a larger axial velocity component than isotropic permeability. A parameter study revealed that results are most sensitive to the lobule size and radial pressure drop. Our model provides insight into hepatic microhaemodynamics, and suggests that inclusion of VS in the model leads to perfusion patterns that are likely to reflect physiological reality. The model has potential for applications to unphysiological and pathological conditions.
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Affiliation(s)
- Charlotte Debbaut
- a Biofluid, Tissue and Solid Mechanics for Medical Applications (bioMMeda), Institute Biomedical Technology, Ghent University , Campus Heymans - Blok B, De Pintelaan 185, 9000 Gent , Belgium
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Palladini G, Ferrigno A, Rizzo V, Boncompagni E, Richelmi P, Freitas I, Perlini S, Vairetti M. Lobe-specific heterogeneity and matrix metalloproteinase activation after ischemia/reperfusion injury in rat livers. Toxicol Pathol 2012; 40:722-30. [PMID: 22549974 DOI: 10.1177/0192623312441403] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Studies assessing the effects of partial-hepatic ischemia/reperfusion (I/R) injury focused on the damage to the ischemic-lobe, whereas few data are available on non-ischemic lobe. This study investigated whether acute liver I/R does affect non-ischemic lobe function via modulation of extracellular matrix remodeling. Male Sprague-Dawley rats underwent left lateral- and median-lobe ischemia for 30 min and reperfusion for 60 min or sham operation. After reperfusion, blood samples and hepatic biopsies from both the ischemic (left-lobe, LL) and the non-ischemic lobe (right-lobe, RL) were collected. Serum hepatic enzymes and TNF-alpha, tissue matrix metalloproteinases (MMP-2, MMP-9), liver morphology, malondialdehyde (MDA), and myeloperoxidase (MPO) were evaluated. Liver I/R injury was confirmed by altered increased hepatic enzymes and TNF-alpha. I/R induced an altered morphology and an increase in MMP-2 and MMP-9 activity not only in left-ischemic lobe (LL) but also in the right-non-ischemic (RL) lobe. A lobar difference was detected for MDA formation and MPO activity in both sham and I/R submitted rats, with higher levels in the left lobe for both groups. This study indicates that an increase in MMPs, which may be TNF-alpha-mediated, occurs in both the ischemic- and the non-ischemic lobes; the heterogeneous lobe concentrations of MDA and MPO suggest that the random sampling of liver tissue should be avoided.
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Rowe A, Zhang L, Hussain A, Braet F, Ramzan I. Assessment and histological analysis of the IPRL technique for sequential in situ liver biopsy. COMPARATIVE HEPATOLOGY 2011; 10:7. [PMID: 21819626 PMCID: PMC3199742 DOI: 10.1186/1476-5926-10-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Accepted: 08/08/2011] [Indexed: 11/10/2022]
Abstract
BACKGROUND The isolated perfused rat liver (IPRL) is a technique used in a wide range of liver studies. Typically livers are assessed at treatment end point. Techniques have been described to biopsy liver in the live rat and post-hepatectomy. RESULTS This paper describes a technique for obtaining two full and one partial lobe biopsies from the liver in situ during an IPRL experiment. Our approach of retaining the liver in situ assists in minimising liver capsule damage, and consequent leakage of perfusate, maintains the normal anatomical position of the liver during perfusion and helps to keep the liver warm and moist. Histological results from sequential lobe biopsies in control perfusions show that cytoplasmic vacuolation of hepatocytes is a sign of liver deterioration, and when it occurs it commences as a diffuse pattern which tends to develop a circumscribed, centrilobular pattern as perfusion progresses. CONCLUSIONS Liver lobe biopsies obtained using this method can be used to study temporal effects of drug treatments and are suitable for light and electron microscopy, and biochemical analyses.
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Affiliation(s)
- Anthony Rowe
- Faculty of Pharmacy, University of Sydney, NSW 2006, Australia.
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Thoolen B, Maronpot RR, Harada T, Nyska A, Rousseaux C, Nolte T, Malarkey DE, Kaufmann W, Küttler K, Deschl U, Nakae D, Gregson R, Vinlove MP, Brix AE, Singh B, Belpoggi F, Ward JM. Proliferative and nonproliferative lesions of the rat and mouse hepatobiliary system. Toxicol Pathol 2011; 38:5S-81S. [PMID: 21191096 DOI: 10.1177/0192623310386499] [Citation(s) in RCA: 398] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The INHAND Project (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) is a joint initiative of the Societies of Toxicologic Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP) and North America (STP) to develop an internationally-accepted nomenclature for proliferative and non-proliferative lesions in laboratory animals. The purpose of this publication is to provide a standardized nomenclature and differential diagnosis for classifying microscopic lesions observed in the hepatobiliary system of laboratory rats and mice, with color microphotographs illustrating examples of some lesions. The standardized nomenclature presented in this document is also available for society members electronically on the internet (http://goreni.org). Sources of material included histopathology databases from government, academia, and industrial laboratories throughout the world. Content includes spontaneous and aging lesions as well as lesions induced by exposure to test materials. A widely accepted and utilized international harmonization of nomenclature for lesions of the hepatobiliary system in laboratory animals will decrease confusion among regulatory and scientific research organizations in different countries and provide a common language to increase and enrich international exchanges of information among toxicologists and pathologists.
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Affiliation(s)
- Bob Thoolen
- Global Pathology Support, The Hague, The Netherlands.
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Desmet VJ. Ductal plates in hepatic ductular reactions. Hypothesis and implications. II. Ontogenic liver growth in childhood. Virchows Arch 2011; 458:261-70. [PMID: 21298286 DOI: 10.1007/s00428-011-1049-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2010] [Revised: 01/18/2011] [Accepted: 01/18/2011] [Indexed: 01/09/2023]
Abstract
This article discusses the processes of bile duct growth and new lobule formation in the liver during childhood in the light of the ductal plate (DP) hypothesis. Unlike in other organs in which tubular elongation and branching ends with the creation of the organ-specific terminal differentiation products, in the liver a steadily enlarging parenchymal mass needs to establish continuity of its canalicular network with the existing bile duct system. The hypothesis suggests that this occurs by DP formation, like in the embryonic liver, and further assumes that pathological ductular reactions (DRs) induced by cholestasis or hypoxia are amplified equivalents of similar mechanisms operating at low level during liver growth. The concept is confronted with data on porcine liver growth, since swine and non-swine liver growth is thought to be comparable. Relative bile acid load may be the driving force for establishment of new canaliculo-ductular connections, supported in zones of relative hypoxia by hypoxia-inducible factor 1 alpha secreted by hepatocytes. The latter mechanism is at the base for induction of appropriate vascular changes in selected sinusoids, resulting in the development of portal inlet venules and additional draining central veins. The process gives rise to the formation of new single lobules by formation of new portal tracts or to the transformation of single lobules in compound lobules by development of new vascular septa. The concept of postnatal DP formation is important in the elucidation of several unexplained findings in adult liver diseases.
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Affiliation(s)
- Valeer J Desmet
- Department of Pathology, University Hospital K.U.Leuven, Rafael, Leuven, Belgium.
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Bonfiglio A, Leungchavaphongse K, Repetto R, Siggers JH. Mathematical Modeling of the Circulation in the Liver Lobule. J Biomech Eng 2010; 132:111011. [DOI: 10.1115/1.4002563] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this paper, we develop a mathematical model of blood circulation in the liver lobule. We aim to find the pressure and flux distributions within a liver lobule. We also investigate the effects of changes in pressure that occur following a resection of part of the liver, which often leads to high pressure in the portal vein. The liver can be divided into functional units called lobules. Each lobule has a hexagonal cross-section, and we assume that its longitudinal extent is large compared with its width. We consider an infinite lattice of identical lobules and study the two-dimensional flow in the hexagonal cross-sections. We model the sinusoidal space as a porous medium, with blood entering from the portal tracts (located at each of the vertices of the cross-section of the lobule) and exiting via the centrilobular vein (located in the center of the cross-section). We first develop and solve an idealized mathematical model, treating the porous medium as rigid and isotropic and blood as a Newtonian fluid. The pressure drop across the lobule and the flux of blood through the lobule are proportional to one another. In spite of its simplicity, the model gives insight into the real pressure and velocity distribution in the lobule. We then consider three modifications of the model that are designed to make it more realistic. In the first modification, we account for the fact that the sinusoids tend to be preferentially aligned in the direction of the centrilobular vein by considering an anisotropic porous medium. In the second, we account more accurately for the true behavior of the blood by using a shear-thinning model. We show that both these modifications have a small quantitative effect on the behavior but no qualitative effect. The motivation for the final modification is to understand what happens either after a partial resection of the liver or after an implantation of a liver of small size. In these cases, the pressure is observed to rise significantly, which could cause deformation of the tissue. We show that including the effects of tissue compliance in the model means that the total blood flow increases more than linearly as the pressure rises.
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Affiliation(s)
- Andrea Bonfiglio
- Department of Civil, Environmental and Architectural Engineering, University of Genoa, Via Montallegro 1, 16145 Genoa, Italy
| | | | - Rodolfo Repetto
- Department of Civil, Environmental and Architectural Engineering, University of Genoa, Via Montallegro 1, 16145 Genoa, Italy
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Wambaugh J, Shah I. Simulating microdosimetry in a virtual hepatic lobule. PLoS Comput Biol 2010; 6:e1000756. [PMID: 20421935 PMCID: PMC2858695 DOI: 10.1371/journal.pcbi.1000756] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2009] [Accepted: 03/23/2010] [Indexed: 12/21/2022] Open
Abstract
The liver plays a key role in removing harmful chemicals from the body and is therefore often the first tissue to suffer potentially adverse consequences. To protect public health it is necessary to quantitatively estimate the risk of long-term low dose exposure to environmental pollutants. Animal testing is the primary tool for extrapolating human risk but it is fraught with uncertainty, necessitating novel alternative approaches. Our goal is to integrate in vitro liver experiments with agent-based cellular models to simulate a spatially extended hepatic lobule. Here we describe a graphical model of the sinusoidal network that efficiently simulates portal to centrilobular mass transfer in the hepatic lobule. We analyzed the effects of vascular topology and metabolism on the cell-level distribution following oral exposure to chemicals. The spatial distribution of metabolically inactive chemicals was similar across different vascular networks and a baseline well-mixed compartment. When chemicals were rapidly metabolized, concentration heterogeneity of the parent compound increased across the vascular network. As a result, our spatially extended lobule generated greater variability in dose-dependent cellular responses, in this case apoptosis, than were observed in the classical well-mixed liver or in a parallel tubes model. The mass-balanced graphical approach to modeling the hepatic lobule is computationally efficient for simulating long-term exposure, modular for incorporating complex cellular interactions, and flexible for dealing with evolving tissues. Virtual tissues are emerging as a powerful tool for computational biology. By encoding known biology into a simulation of tissue function, gaps in knowledge can be identified. As a simulation of tissue function, in silico experiments can be performed inexpensively and rapidly. There are over 6000 chemicals produced in large quantities that may be present in our environment, many of which have not been thoroughly examined for human toxicity. Traditional toxicity testing is expensive, lengthy, and relies heavily upon the use of animals. For this reason in vitro toxicity testing techniques are being developed. However, techniques are needed to relate in vitro results to in vivo conditions. The liver is often the first tissue to show signs of toxicity and therefore a predictive liver toxicity simulator would be a powerful tool to reduce the financial and animal cost of toxicity testing. As a first step, we have developed a model for relating environmental exposure to cell-level concentrations; a model for virtual tissue microdosimetry. We identify regimes in which this approach is equivalent to previous techniques, as well as regimes where large cell-to-cell variability exists. This variability should have consequences both for normal liver function and the onset of injury.
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Affiliation(s)
- John Wambaugh
- National Center for Computational Toxicology, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, United States of America.
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38
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Vollmar B, Menger MD. The hepatic microcirculation: mechanistic contributions and therapeutic targets in liver injury and repair. Physiol Rev 2009; 89:1269-339. [PMID: 19789382 DOI: 10.1152/physrev.00027.2008] [Citation(s) in RCA: 352] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The complex functions of the liver in biosynthesis, metabolism, clearance, and host defense are tightly dependent on an adequate microcirculation. To guarantee hepatic homeostasis, this requires not only a sufficient nutritive perfusion and oxygen supply, but also a balanced vasomotor control and an appropriate cell-cell communication. Deteriorations of the hepatic homeostasis, as observed in ischemia/reperfusion, cold preservation and transplantation, septic organ failure, and hepatic resection-induced hyperperfusion, are associated with a high morbidity and mortality. During the last two decades, experimental studies have demonstrated that microcirculatory disorders are determinants for organ failure in these disease states. Disorders include 1) a dysregulation of the vasomotor control with a deterioration of the endothelin-nitric oxide balance, an arterial and sinusoidal constriction, and a shutdown of the microcirculation as well as 2) an overwhelming inflammatory response with microvascular leukocyte accumulation, platelet adherence, and Kupffer cell activation. Within the sequelae of events, proinflammatory mediators, such as reactive oxygen species and tumor necrosis factor-alpha, are the key players, causing the microvascular dysfunction and perfusion failure. This review covers the morphological and functional characterization of the hepatic microcirculation, the mechanistic contributions in surgical disease states, and the therapeutic targets to attenuate tissue injury and organ dysfunction. It also indicates future directions to translate the knowledge achieved from experimental studies into clinical practice. By this, the use of the recently introduced techniques to monitor the hepatic microcirculation in humans, such as near-infrared spectroscopy or orthogonal polarized spectral imaging, may allow an early initiation of treatment, which should benefit the final outcome of these critically ill patients.
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Affiliation(s)
- Brigitte Vollmar
- Institute for Experimental Surgery, University of Rostock, Rostock, Germany.
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Papp V, Dezsö K, László V, Nagy P, Paku S. Architectural changes during regenerative and ontogenic liver growth in the rat. Liver Transpl 2009; 15:177-83. [PMID: 19177433 DOI: 10.1002/lt.21665] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Although liver architecture has a major impact on function, morphological aspects of liver growth are relatively neglected. In our recent experiments, the architectural changes of the rat liver were compared during 2 basic processes: ontogeny and regenerative liver growth. The hepatic tissue is constructed as structural/functional units, and probably the most established and well-defined such unit is the classic lobule. The extent and orientation of the lobules are variable in the liver, and this renders their accurate size determination more difficult. The filling of the liver vasculature by a colored resin nicely outlined the surface lobules, enabling an analysis of the alterations of these structures during liver growth. There are 3 structural components of postnatal physiological liver development: enlargement of the hepatocytes and expansion and multiplication of the liver lobules. However, the enlargement of the lobules is exclusively responsible for the regenerative liver growth following partial hepatectomy. The number of hepatic lobules does not change during this latter reaction, but they gain a more complex, irregular structure.
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Affiliation(s)
- Veronika Papp
- First Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
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40
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Mccuskey RS. The Hepatic Microvascular System in Health and Its Response to Toxicants. Anat Rec (Hoboken) 2008; 291:661-71. [DOI: 10.1002/ar.20663] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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41
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Modeling and Simulation of Hepatic Drug Disposition Using a Physiologically Based, Multi-agent In Silico Liver. Pharm Res 2007; 25:1023-36. [DOI: 10.1007/s11095-007-9494-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2007] [Accepted: 10/30/2007] [Indexed: 11/26/2022]
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42
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Hardman RC, Volz DC, Kullman SW, Hinton DE. An in vivo look at vertebrate liver architecture: three-dimensional reconstructions from medaka (Oryzias latipes). Anat Rec (Hoboken) 2007; 290:770-82. [PMID: 17516461 DOI: 10.1002/ar.20524] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Understanding three-dimensional (3D) hepatobiliary architecture is fundamental to elucidating structure/function relationships relevant to hepatobiliary metabolism, transport, and toxicity. To date, factual information on vertebrate liver architecture in 3 dimensions has remained limited. Applying noninvasive in vivo imaging to a living small fish animal model we elucidated, and present here, the 3D architecture of this lower vertebrate liver. Our investigations show that hepatobiliary architecture in medaka is based on a polyhedral (hexagonal) structural motif, that the intrahepatic biliary system is an interconnected network of canaliculi and bile-preductules, and that parenchymal architecture in this lower vertebrate is more related to that of the mammalian liver than previously believed. The in vivo findings presented advance our comparative 3D understanding of vertebrate liver structure/function, help clarify previous discrepancies among vertebrate liver conceptual models, and pose interesting questions regarding the "functional unit" of the vertebrate liver.
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Affiliation(s)
- Ron C Hardman
- Duke University, Nicholas School of the Environment and Earth Sciences, Durham, North Carolina 27708, USA
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43
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Lin DW, Johnson S, Hunt CA. Modeling liver physiology: combining fractals, imaging and animation. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2004:3120-3. [PMID: 17270940 DOI: 10.1109/iembs.2004.1403881] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Physiological modeling of vascular and microvascular networks in several key human organ systems is critical for a deeper understanding of pharmacology and the effect of pharmacotherapies on disease. Like the lung and the kidney, the morphology of its vascular and microvascular system plays a major role in its functional capability. To understand liver function in absorption and metabolism of food and drugs, one must examine the morphology and physiology at both higher and lower level liver function. We have developed validated virtualized dynamic three dimensional (3D) models of liver secondary units and primary units by combining a number of different methods: three-dimensional rendering, fractals, and animation. We have simulated particle dynamics in the liver secondary unit. The resulting models are suitable for use in helping researchers easily visualize and gain intuition on results of in silico liver experiments.
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Affiliation(s)
- Debbie W Lin
- Department of Biological and Medical Informatics, University of California San Francisco, CA 94143, USA
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44
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Yan L, Hunt CA, Ropella GEP, Roberts MS. In silico representation of the liver-connecting function to anatomy, physiology and heterogeneous microenvironments. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2004:853-6. [PMID: 17271811 DOI: 10.1109/iembs.2004.1403292] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We have built a collection of flexible, hepatomimetic, in silico components. Some are agent-based. We assemble them into devices that mimic aspects of anatomic structures and the behaviors of hepatic lobules (the primary functional unit of the liver) along with aspects of liver function. We validate against outflow profiles for sucrose administered as a bolus to isolated, perfused rat livers (IPRLs). Acceptable in silico profiles are experimentally indistinguishable from those of the in situ referent based on similarity measure values. The behavior of these devices is expected to cover expanding portions of the behavior space of real livers and their components. These in silico livers will provide powerful tools for understanding how the liver functions in normal and diseased states, at multiple levels of organization.
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Affiliation(s)
- Li Yan
- Bioeng. Graduate Program, California Univ., San Francisco, CA, USA
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45
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Dombrowski F, Evert M. Revelation of simple and complex liver acini after portal transplantation of pancreatic islets or thyroid follicles in rats. Hepatology 2007; 45:705-15. [PMID: 17326145 DOI: 10.1002/hep.21559] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
UNLABELLED The microarchitecture of the liver is still not completely understood although various concepts of structural liver organization have been proposed. Among them, Rappaport's liver acinus stands out as one of the most accepted models. The correctness of this model, however, has also been doubted, and its applicability is hampered by the fact that the outlines of the liver acinus are disguised and nobody was ever able to give visual evidence by "unmasking" a simple liver acinus from the surrounding liver tissue. After intraportal transplantation of pancreatic islets or thyroid follicles into diabetic or thyroidectomized rats, respectively, the transplants engraft in small portal tracts and morphologically alter the downstream liver tissue due to excessive hormone secretion. Using a combined approach of perfusion fixation, stereomicroscopy, and light microscopy, we demonstrate in this study that these foci of altered liver tissue represent simple and complex liver acini, exactly as described by Rappaport. We present stereomicroscopical and histological examples of all important cut levels of altered simple and complex liver acini, including their topographical relation to the supplying and draining vessels and to the "central vein" liver lobule. Moreover, by computer-aided reconstruction of serial semi-thin sections, we were able to present the first 3-dimensional images of simple and complex liver acini. CONCLUSION Our results prove the correctness of Rappaport's acinus model and confirm the simple liver acinus as the principal microcirculatory unit of the liver.
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46
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Hunt CA, Ropella GEP, Yan L, Hung DY, Roberts MS. Physiologically based synthetic models of hepatic disposition. J Pharmacokinet Pharmacodyn 2006; 33:737-72. [PMID: 17051440 DOI: 10.1007/s10928-006-9031-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2006] [Accepted: 08/17/2006] [Indexed: 10/24/2022]
Abstract
Current physiologically based pharmacokinetic (PBPK) models are inductive. We present an additional, different approach that is based on the synthetic rather than the inductive approach to modeling and simulation. It relies on object-oriented programming. A model of the referent system in its experimental context is synthesized by assembling objects that represent components such as molecules, cells, aspects of tissue architecture, catheters, etc. The single pass perfused rat liver has been well described in evaluating hepatic drug pharmacokinetics (PK) and is the system on which we focus. In silico experiments begin with administration of objects representing actual compounds. Data are collected in a manner analogous to that in the referent PK experiments. The synthetic modeling method allows for recognition and representation of discrete event and discrete time processes, as well as heterogeneity in organization, function, and spatial effects. An application is developed for sucrose and antipyrine, administered separately and together. PBPK modeling has made extensive progress in characterizing abstracted PK properties but this has also been its limitation. Now, other important questions and possible extensions emerge. How are these PK properties and the observed behaviors generated? The inherent heuristic limitations of traditional models have hindered getting meaningful, detailed answers to such questions. Synthetic models of the type described here are specifically intended to help answer such questions. Analogous to wet-lab experimental models, they retain their applicability even when broken apart into sub-components. Having and applying this new class of models along with traditional PK modeling methods is expected to increase the productivity of pharmaceutical research at all levels that make use of modeling and simulation.
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Affiliation(s)
- C Anthony Hunt
- The UCSF/UCB Joint Graduate Group in Bioengineering, University of California, Berkeley, CA, USA.
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Nahmias Y, Arneja A, Tower TT, Renn MJ, Odde DJ. Cell patterning on biological gels via cell spraying through a mask. ACTA ACUST UNITED AC 2006; 11:701-8. [PMID: 15998211 DOI: 10.1089/ten.2005.11.701] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We present an easily applicable and inexpensive method for patterning cells on arbitrary surfaces including biological gels with little loss of viability or function. Single-cell suspensions of human umbilical vein endothelial cells and NIH 3T3 fibroblasts were sprayed with an off-the-shelf airbrush through a mask to create 100-microm scale patterns on collagen gels. Three-dimensional patterns were created by layering a collagen gel on top of the first pattern and patterning the top gel. Coculture of rat hepatocytes with NIH 3T3 patterns on collagen gels resulted in localized increased activity of cytochrome P-450 along the pattern. These results suggest that cell spraying is a useful tool for the study of heterotypic cellular interactions and tissue-engineering applications on biologically relevant matrices, and for the creation of three-dimensional cell patterns in vitro.
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Affiliation(s)
- Yaakov Nahmias
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Abstract
The morphological homogeneity of the liver parenchyma has represented a major obstacle in finding an acceptable definition of the structural/functional units of the liver. Concepts such as the "lobule," the "portal unit" and the "acinus" remain debatable. This study investigates the modular microarchitecture on the basis of the lobular concept. Using alkaline phosphatase activity as a histochemical marker, modules could be recognized clearly. In autopsy specimens of human liver, modules were traced through sequential cryosections, and a "secondary" module having a height of 1.9 mm, a surface of 14.7 mm(2), and a volume of 5.1 mm(3) was reconstructed three-dimensionally. It was subdivided into 14 "primary" modules by portal tracts and vascular septa and by a common draining central venular tree. Primary modules were polyhedral, with seven to nine facets, having heights from 0.3 to 0.9 mm, surface areas from 1.7 to 5.0 mm(2), and volumes from 0.1 to 0.9 mm(3). Such variation in shape and size is considered an important part of the modular organization of the human liver. In conclusion, the findings on the three-dimensionality and microcirculation of liver modules support and extend the lobular concept and, at the same time, make apparent the shortcomings of the concepts of acinar and portal units. The results of this study should permit a better interpretation of histological sections of normal and pathological liver and provide a basis for understanding the metabolic heterogeneity of liver cells and their functional integration into parenchymal units.
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Affiliation(s)
- Harald F Teutsch
- Department of Anatomy and Cell Biology, University of Ulm, Albert-Einstein-Allee 11, D-89069 Ulm, Germany.
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Irwin RD, Parker JS, Lobenhofer EK, Burka LT, Blackshear PE, Vallant MK, Lebetkin EH, Gerken DF, Boorman GA. Transcriptional profiling of the left and median liver lobes of male f344/n rats following exposure to acetaminophen. Toxicol Pathol 2005; 33:111-7. [PMID: 15805062 DOI: 10.1080/01926230590522257] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The liver is a common organ for transcriptional profiling because of its role in xenobiotic metabolism and because hepatotoxicity is a common response to chemical exposure. To explore the impact that sampling different lobes may have on transcriptional profiling experiments we have examined and compared gene expression profiles of the left and median lobes of livers from male F344 rats exposed to toxic and nontoxic doses of acetaminophen. Transcript profiling using micorarrays revealed clear differences in the response of the left and median liver lobes of F344 rats to acetaminophen exposure both at low doses as well as doses that caused hepatotoxicity. Differences were found in the total number of differentially expressed genes in the left and median lobes, the number and identity of genes that were differentially expressed uniquely only in the left or median lobe, and in the patterns of gene expression. While it is not possible to generalize these results to compounds other than acetaminophen or other strains of rat, these results highlight the potential impact of sampling differences on the interpretation of gene expression profiles in the liver.
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Affiliation(s)
- Richard D Irwin
- Environmental Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA.
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50
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Malarkey DE, Johnson K, Ryan L, Boorman G, Maronpot RR. New insights into functional aspects of liver morphology. Toxicol Pathol 2005; 33:27-34. [PMID: 15805053 DOI: 10.1080/01926230590881826] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The liver is structurally and functionally complex and has been considered second only to brain in its complexity. Many mysteries still exist in this heterogeneous tissue whose functional unit of the lobule has continued to stump morphologists for over 300 years. The primary lobule, proposed by Matsumoto in 1979, has been gaining acceptance as the functional unit of the liver over other conceptual views because it's based on vessel architecture and includes the classic lobule as a secondary feature. Although hepatocytes comprise almost 80% of the liver, there are at least another dozen cell types, many of which provide "cross-talk" and play important functional roles in the normal and diseased liver. The distribution and functional roles of all cells in the liver must be carefully considered in both the analysis and interpretation of research data, particularly data in the area of genomics and "phenotypic anchoring" of gene expression results. Discoveries regarding the functional heterogeneity of the various liver cell types, including hepatocytes, hepatic stellate cells, sinusoidal endothelia, and Kupffer cells, are providing new insights into our understanding of the development, prevention and treatment of liver disease. For example, functional differences along zonal patterns (centrilobular or periportal) have been demonstrated for sinusoidal endothelium, Kupffer cells, and hepatocytes and can explain the gradients and manifestations of disease observed within lobules. Intralobular gradients of bile uptake, glycogen depletion, glutamine synthetase, and carboxylesterase by hepatocytes; widened fenestrations in centrilobular sinusoidal lining cells; and differences in the components of centrilobular extracellular matrix or function of Kupffer cells have been demonstrated. Awareness of the complexities and heterogeneity of the liver will add to a greater understanding of liver function and disease processes that lead to toxicity, cancer, and other diseases.
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Affiliation(s)
- David E Malarkey
- National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA.
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