120 results on '"Walter L. Murfee"'
Search Results
2. Editorial: Putting engineering back in vascular tissue engineering to advance basic science and clinical applications
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Walter L. Murfee and Jessica E. Wagenseil
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vascular ,tissue engineering ,mechanics ,design ,blood vessel ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Published
- 2022
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3. A Challenge for Engineering Biomimetic Microvascular Models: How do we Incorporate the Physiology?
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Arinola O. Lampejo, Nien-Wen Hu, Daniela Lucas, Banks M. Lomel, Christian M. Nguyen, Carmen C. Dominguez, Bing Ren, Yong Huang, and Walter L. Murfee
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angiogenesis ,lymphangiogenesis ,microcirculation ,tissue engeneering ,biomimetic ,Biotechnology ,TP248.13-248.65 - Abstract
The gap between in vitro and in vivo assays has inspired biomimetic model development. Tissue engineered models that attempt to mimic the complexity of microvascular networks have emerged as tools for investigating cell-cell and cell-environment interactions that may be not easily viewed in vivo. A key challenge in model development, however, is determining how to recreate the multi-cell/system functional complexity of a real network environment that integrates endothelial cells, smooth muscle cells, vascular pericytes, lymphatics, nerves, fluid flow, extracellular matrix, and inflammatory cells. The objective of this mini-review is to overview the recent evolution of popular biomimetic modeling approaches for investigating microvascular dynamics. A specific focus will highlight the engineering design requirements needed to match physiological function and the potential for top-down tissue culture methods that maintain complexity. Overall, examples of physiological validation, basic science discoveries, and therapeutic evaluation studies will emphasize the value of tissue culture models and biomimetic model development approaches that fill the gap between in vitro and in vivo assays and guide how vascular biologists and physiologists might think about the microcirculation.
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- 2022
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4. Evaluation of Arteriolar Smooth Muscle Cell Function in an Ex Vivo Microvascular Network Model
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Jessica M. Motherwell, Mohammad S. Azimi, Kristine Spicer, Natascha G. Alves, Nicholas A. Hodges, Jerome W. Breslin, Prasad V. G. Katakam, and Walter L. Murfee
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Medicine ,Science - Abstract
Abstract An emerging challenge in tissue engineering biomimetic models is recapitulating the physiological complexity associated with real tissues. Recently, our laboratory introduced the rat mesentery culture model as an ex vivo experimental platform for investigating the multi-cellular dynamics involved in angiogenesis within an intact microvascular network using time-lapse imaging. A critical question remains whether the vessels maintain their functionality. The objective of this study was to determine whether vascular smooth muscle cells in cultured microvascular networks maintain the ability to constrict. Adult rat mesenteric tissues were harvested and cultured for three days in either MEM or MEM plus 10% serum. On Day 0 and Day 3 live microvascular networks were visualized with FITC conjugated BSI-lectin labeling and arteriole diameters were compared before and five minutes after topical exposure to vasoconstrictors (50 mM KCl and 20 nM Endothelin-1). Arterioles displayed a vasoconstriction response to KCl and endothelin for each experimental group. However, the Day 3 serum cultured networks were angiogenic, characterized by increased vessel density, and displayed a decreased vasoconstriction response compared to Day 0 networks. The results support the physiological relevance of the rat mesentery culture model as a biomimetic tool for investigating microvascular growth and function ex vivo.
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- 2017
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5. Aging related impairment of brain microvascular bioenergetics involves oxidative phosphorylation and glycolytic pathways
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Siva SVP Sakamuri, Venkata N Sure, Lahari Kolli, Wesley R Evans, Jared A Sperling, Gregory J Bix, Xiaoying Wang, Dmitriy N Atochin, Walter L Murfee, Ricardo Mostany, and Prasad VG Katakam
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Male ,Aging ,Brain ,Original Articles ,Oxidative Phosphorylation ,Mice ,Adenosine Triphosphate ,Oxygen Consumption ,Neurology ,Animals ,Neurology (clinical) ,Energy Metabolism ,Cardiology and Cardiovascular Medicine ,Glycolysis - Abstract
Mitochondrial and glycolytic energy pathways regulate the vascular functions. Aging impairs the cerebrovascular function and increases the risk of stroke and cognitive dysfunction. The goal of our study is to characterize the impact of aging on brain microvascular energetics. We measured the oxygen consumption and extracellular acidification rates of freshly isolated brain microvessels (BMVs) from young (2–4 months) and aged (20–22 months) C57Bl/6 male mice. Cellular ATP production in BMVs was predominantly dependent on oxidative phosphorylation (OXPHOS) with glucose as the preferred energy substrate. Aged BMVs exhibit lower ATP production rate with diminished OXPHOS and glycolytic rate accompanied by increased utilization of glutamine. Impairments of glycolysis displayed by aged BMVs included reduced compensatory glycolysis whereas impairments of mitochondrial respiration involved reduction of spare respiratory capacity and proton leak. Aged BMVs showed reduced levels of key glycolysis proteins including glucose transporter 1 and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 but normal lactate dehydrogenase activity. Mitochondrial protein levels were mostly unchanged whereas citrate synthase activity was reduced, and glutamate dehydrogenase was increased in aged BMVs. Thus, for the first time, we identified the dominant role of mitochondria in bioenergetics of BMVs and the alterations of the energy pathways that make the aged BMVs vulnerable to injury.
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- 2022
6. Incorporation of Tumor Spheroids into an Ex‐vivo Tissue Culture Model for Investigating Cancer Cell–Microvascular Interactions
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Arinola O. Lampejo, Suzanne E. Lightsey, Blanka R. Sharma, and Walter L. Murfee
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Genetics ,Molecular Biology ,Biochemistry ,Biotechnology - Published
- 2022
7. Estimation of Shear Stress Heterogeneity along Capillary Segments in Angiogenic Rat Mesenteric Microvascular Networks
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Nien‐Wen Hu, Banks Lomel, Peter Balogh, and Walter L. Murfee
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Genetics ,Molecular Biology ,Biochemistry ,Biotechnology - Published
- 2022
8. Stromal Vascular Fraction Reverses the Age-Related Impairment in Revascularization following Injury
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Gabrielle Rowe, David S. Heng, Jason E. Beare, Nicholas A. Hodges, Evan P. Tracy, Walter L. Murfee, and Amanda J. LeBlanc
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Physiology ,Cardiology and Cardiovascular Medicine - Abstract
Adipose-derived stromal vascular fraction (SVF) has emerged as a potential regenerative therapy, but few studies utilize SVF in a setting of advanced age. Additionally, the specific cell population in SVF providing therapeutic benefit is unknown. We hypothesized that aging would alter the composition of cell populations present in SVF and its ability to promote angiogenesis following injury, a mechanism that is T cell-mediated. SVF isolated from young and old Fischer 344 rats was examined with flow cytometry for cell composition. Mesenteric windows from old rats were isolated following exteriorization-induced (EI) hypoxic injury and intravenous injection of one of four cell therapies: (1) SVF from young or (2) old donors, (3) SVF from old donors depleted of or (4) enriched for T cells. Advancing age increased the SVF T-cell population but reduced revascularization following injury. Both young and aged SVF incorporated throughout the host mesenteric microvessels, but only young SVF significantly increased vascular area following EI. This study highlights the effect of donor age on SVF angiogenic efficacy and demonstrates how the ex vivo mesenteric-window model can be used in conjunction with SVF therapy to investigate its contribution to angiogenesis.
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- 2022
9. Glycolytic and Oxidative Phosphorylation Defects Precede the Development of Senescence in Primary Human Brain Microvascular Endothelial Cells
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Siva S. V. P. Sakamuri, Venkata N. Sure, Lahari Kolli, Ning Liu, Wesley R. Evans, Jared A. Sperling, David W. Busija, Xiaoying Wang, Sarah H. Lindsey, Walter L. Murfee, Ricardo Mostany, and Prasad V. G. Katakam
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Aging ,Adenosine Triphosphate ,Glutamine ,Humans ,Endothelial Cells ,Brain ,Original Article ,Geriatrics and Gerontology ,Glycolysis ,Oxidative Phosphorylation - Abstract
Alterations of mitochondrial and glycolytic energy pathways related to aging could contribute to cerebrovascular dysfunction. We studied the impact of aging on energetics of primary human brain microvascular endothelial cells (HBMECs) by comparing the young (passages 7–9), pre-senescent (passages 13–15), and senescent (passages 20–21) cells. Pre-senescent HBMECs displayed decreased telomere length and undetectable telomerase activity although markers of senescence were unaffected. Bioenergetics in HBMECs were determined by measuring the oxygen consumption (OCR) and extracellular acidification (ECAR) rates. Cellular ATP production in young HBMECs was predominantly dependent on glycolysis with glutamine as the preferred fuel for mitochondrial oxidative phosphorylation (OXPHOS). In contrast, pre-senescent HBMECs displayed equal contribution to ATP production rate from glycolysis and OXPHOS with equal utilization of glutamine, glucose, and fatty acids as mitofuels. Compared to young, pre-senescent HBMECs showed a lower overall ATP production rate that was characterized by diminished contribution from glycolysis. Impairments of glycolysis displayed by pre-senescent cells included reduced basal glycolysis, compensatory glycolysis, and non-glycolytic acidification. Furthermore, impairments of mitochondrial respiration in pre-senescent cells involved the reduction of maximal respiration and spare respiratory capacity but intact basal and ATP production-related OCR. Proton leak and non-mitochondrial respiration, however, were unchanged in the pre-senescent HBMECs. HBMECS at passages 20–21 displayed expression of senescence markers and continued similar defects in glycolysis and worsened OXPHOS. Thus, for the first time, we characterized the bioenergetics of pre-senescent HBMECs comprehensively to identify the alterations of the energy pathways that could contribute to aging. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11357-022-00550-2.
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- 2022
10. Viewing stromal vascular fraction de novo vessel formation and association with host microvasculature using the rat mesentery culture model
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Nicholas A. Hodges, Arinola O. Lampejo, Hulan Shang, Gabrielle Rowe, Amanda Jo LeBlanc, Adam J. Katz, and Walter L. Murfee
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Male ,Stromal Vascular Fraction ,Neovascularization, Pathologic ,Physiology ,Endothelial Cells ,Rats ,Rats, Sprague-Dawley ,Adipose Tissue ,Physiology (medical) ,Microvessels ,Animals ,Mesentery ,Stromal Cells ,Rats, Wistar ,Cardiology and Cardiovascular Medicine ,Molecular Biology - Abstract
The objective of the study is to demonstrate the innovation and utility of mesenteric tissue culture for discovering the microvascular growth dynamics associated with adipose-derived stromal vascular fraction (SVF) transplantation. Understanding how SVF cells contribute to de novo vessel growth (i.e., neovascularization) and host network angiogenesis motivates the need to make observations at single-cell and network levels within a tissue.Stromal vascular fraction was isolated from the inguinal adipose of adult male Wistar rats, labeled with DiI, and seeded onto adult Wistar rat mesentery tissues. Tissues were then cultured in MEM + 10% FBS for 3 days and labeled for BSI-lectin to identify vessels. Alternatively, SVF and tissues from green fluorescent-positive (GFP) Sprague Dawley rats were used to track SVF derived versus host vasculature.Stromal vascular fraction-treated tissues displayed a dramatically increased vascularized area compared to untreated tissues. DiI and GFP+ tracking of SVF identified neovascularization involving initial segment formation, radial outgrowth from central hub-like structures, and connection of segments. Neovascularization was also supported by the formation of segments in previously avascular areas. New segments characteristic of SVF neovessels contained endothelial cells and pericytes. Additionally, a subset of SVF cells displayed the ability to associate with host vessels and the presence of SVF increased host network angiogenesis.The results showcase the use of the rat mesentery culture model as a novel tool for elucidating SVF cell transplant dynamics and highlight the impact of model selection for visualization.
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- 2022
11. The effect of microvascular pattern alterations on network resistance in spontaneously hypertensive rats.
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Ming Yang and Walter L. Murfee
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- 2012
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12. A novel tissue culture model for evaluating the effect of aging on stem cell fate in adult microvascular networks
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Maria F. Dutreil, Ryan L. Fishel, Bruce A. Bunnell, Nicholas A. Hodges, Walter L. Murfee, Mohammad S. Azimi, Adam J. Katz, Jessica M. Motherwell, and Matthew Nice
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Aging ,Angiogenesis ,Stem Cells ,Cellular differentiation ,Methods Paper ,Mesenchymal stem cell ,Endothelial Cells ,Neovascularization, Physiologic ,Cell Differentiation ,Biology ,Rats ,Cell biology ,Tissue Culture Techniques ,Tissue culture ,medicine.anatomical_structure ,Lymphatic system ,Microvessels ,medicine ,Animals ,Pericyte ,Rats, Wistar ,Geriatrics and Gerontology ,Stem cell ,Ex vivo - Abstract
In vitro models of angiogenesis are valuable tools for understanding the underlying mechanisms of pathological conditions and for the preclinical evaluation of therapies. Our laboratory developed the rat mesentery culture model as a new tool for investigating mechanistic cell–cell interactions at specific locations across intact blood and lymphatic microvascular networks ex vivo. The objective of this study was to report a method for evaluating the effect of aging on human stem cell differentiation into pericytes during angiogenesis in cultured microvascular networks. DiI labeled exogenous stem cells were seeded onto harvested adult Wistar rat mesenteric tissues and cultured in alpha-MEM + 1% serum for up to 5 days according to four experimental groups: (1) adult human adipose–derived stem cells (hASCs), (2) aged hASCs, (3) adult human bone marrow-derived stem cells (hBMSCs), and (4) aged hBMSCs. Angiogenesis per experimental group was supported by observation of increased vessel density and capillary sprouting. For each tissue per experimental group, a subset of cells was observed in typical pericyte location wrapped along blood vessels. Stem cell differentiation into pericytes was supported by the adoption of elongated pericyte morphology along endothelial cells and positive NG2 labeling. The percentage of cells in pericyte locations was not significantly different across the experimental groups, suggesting that aged mesenchymal stem cells are able to retain their differentiation capacity. Our results showcase an application of the rat mesentery culture model for aging research and the evaluation of stem cell fate within intact microvascular networks.
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- 2020
13. A Novel Ex Vivo Method for Investigating Vascularization of Transplanted Islets
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Robert Dolan, Arinola O. Lampejo, Jorge Santini-González, Nicholas A. Hodges, Edward A. Phelps, and Walter L. Murfee
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endocrine system ,Neovascularization, Pathologic ,Physiology ,Lectins ,Microvessels ,Animals ,Endothelial Cells ,Neovascularization, Physiologic ,Cardiology and Cardiovascular Medicine ,Pericytes ,Article ,Rats - Abstract
Revascularization of transplanted pancreatic islets is critical for survival and treatment of type 1 diabetes. Questions concerning how islets influence local microvascular networks and how networks form connections with islets remain understudied and motivate the need for new models that mimic the complexity of real tissue. Recently, our laboratory established the rat mesentery culture model as a tool to investigate cell dynamics involved in microvascular growth. An advantage is the ability to observe blood vessels, lymphatics, and immune cells. The objective of this study was to establish the rat mesentery tissue culture model as a useful tool to investigate islet tissue integration. DiI-labeled islets were seeded onto adult rat mesentery tissues and cultured for up to 3 days. Live lectin labeling enabled time-lapse observation of vessel growth. During culture, DiI-positive islets remained intact. Radial lectin-positive capillary sprouts with DiI labeling were observed to form from islets and connect to host networks. Lectin-positive vessels from host networks were also seen growing toward islets. PECAM and NG2 labeling confirmed that vessels sprouting from islets contained endothelial cells and pericytes. Our results introduce the rat mesentery culture model as a platform for investigating dynamics associated with the initial revascularization of transplanted islets.
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- 2022
14. An Ex Vivo Tissue Culture Method for Discovering Cell Dynamics Involved in Stromal Vascular Fraction Vasculogenesis Using the Mouse Mesentery
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Dima Majbour, Ariana D. Suarez-Martinez, Nicholas A. Hodges, Arinola O. Lampejo, Banks M. Lomel, Elijah W. Rice, Hulan Shang, Adam J. Katz, and Walter L. Murfee
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- 2022
15. Contributors
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Elena Aikawa, S.G. Anderson, Livia Silva Araújo Passos, Samsul Arefin, Per M. Arvidsson, Alberto Avolio, Martin Bachler, Magnus Bäck, Michael J. Bashline, Dakota Becker-Greene, Jamie Bellinge, Amar Bennasroune, Sébastien Blaise, Barry A. Borlaug, Pierre Boutouyrie, Y. Breet, Jerome W. Breslin, Matthew J. Budoff, Mark Butlin, Marina Cecelja, Chen-Huan Chen, Hao-Min Cheng, Yi-Bang Cheng, Julio A. Chirinos, Phil Chowienczyk, Shao-Yuan Chuang, Marie-Annick Clavel, Jordana B. Cohen, Alexis M. Corcoran, William K. Cornwell, Vicente F. Corrales–Medina, Nancy Côté, Thais Coutinho, James Cox, J.K. Cruickshank, Lu Dai, Stella S. Daskalopoulou, Kevin P. Davy, Marc L. De Buyzere, Paul B. Dieffenbach, Laurent Duca, Girish Dwivedi, David G. Edwards, William B. Farquhar, Bo Fernhall, John S. Floras, Laura E. Fredenburgh, Masafumi Fukumitsu, L. Gafane-Matemane, Nestor Gahungu, Ahmed K. Ghanem, Thierry C. Gillebert, Philippe Gillery, Delphine Gomez, Ezequiel Guzzetti, Bernhard Hametner, Junichiro Hashimoto, Kevin S. Heffernan, Brooks A. Hibner, Sam Hobson, Nien-Wen Hu, T.M. Hughes, Jay D. Humphrey, Stéphane Jaisson, Nadjia Kachenoura, Kazuomi Kario, Prasad V.G. Katakam, Goro Katsuumi, Avinash Kondiboyina, Sándor J. Kovács, R. Kruger, Karolina Kublickiene, Patrick Lacolley, Muriel Laffargue, Arinola O. Lampejo, Agne Laucyte-Cibulskiene, Stéphane Laurent, Hae-Young Lee, Wesley K. Lefferts, Elizabeth C. Lefferts, Adelino F. Leite-Moreira, Chee H. Liew, Joao A.C. Lima, André P. Lourenço, Kaisa Maki-Petaja, Marcy Maracle, Laurent Martiny, Pascal Maurice, Christopher C. Mayer, Barry J. McDonnell, John W. McEvoy, M.L. Meyer, Jean-Baptiste Michel, Philip J. Millar, Tohru Minamino, Gary F. Mitchell, Walter L. Murfee, Jonathan P. Mynard, Massimo Nardone, Peter M. Nilsson, Kevin O'Gallagher, Yoshiaki Ohyama, Kazunori Omote, Jeong Bae Park, Shayn M. Peirce, Philippe Pibarot, Gary L. Pierce, Stuart B. Prenner, Athanase Protogerou, Reed E. Pyeritz, Michael A. Quail, Yogesh N.V. Reddy, Alban Redheuil, Véronique Regnault, Rakhshinda Rehman, Ernst R. Rietzschel, Béatrice Romier-Crouzet, Jasjit Rooprai, Lucia Salvi, Paolo Salvi, Hervé Sartelet, Christian E.H. Schmelzer, A.E. Schutte, Angelina Schwarz, Patrick Segers, James E. Sharman, Ippei Shimizu, Marc A. Simon, Piera Sosa, Bart Spronck, Peter Stenvinkel, Eric J. Stöhr, M. Strauss-Kruger, Ariana Suarez-Martinez, Masayoshi Suda, Shih-Hsien Sung, Isabella Tan, Dimitrios Terentes-Printzios, Raymond R. Townsend, Andrew H. Tran, Elaine M. Urbina, Bharath Ambale Venkatesh, Charalambos Vlachopoulos, Anton Vonk Noordegraaf, Amandine Wahart, Ji-Guang Wang, Siegfried Wassertheurer, Andrew James Webb, Thomas Weber, Berend E. Westerhof, Ian B. Wilkinson, and Yohko Yoshida
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- 2022
16. Linking arterial stiffness to microvascular remodeling
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Arinola O. Lampejo, Nien-Wen Hu, Ariana Suarez-Martinez, Prasad V.G. Katakam, Jerome W. Breslin, Shayn M. Peirce, and Walter L. Murfee
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- 2022
17. Estimation of shear stress values along endothelial tip cells past the lumen of capillary sprouts
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Nien-Wen Hu, Camille D. Rodriguez, Julian A. Rey, Maximillian J. Rozenblum, Connor P. Courtney, Peter Balogh, Malisa Sarntinoranont, and Walter L. Murfee
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Hydrodynamics ,Endothelial Cells ,Cell Biology ,Stress, Mechanical ,Cardiology and Cardiovascular Medicine ,Biochemistry ,Capillaries ,Veins - Abstract
Shear stress is recognized as a regulator of angiogenesis. However, the shear stress experienced by the endothelial cells of capillary sprouts remains unknown. The objective of this study was to estimate shear stress due to local interstitial flow along endothelial tip cells at the end of the capillary sprout lumen. Computational fluid dynamics were used to model flow within a blind-ended vessel, transendothelial flow across the vessel wall, and flow within the surrounding perivascular/interstitial space. Shear stress along the wall of the tip cells was calculated while varying sprout length, perivascular space channel width, and vessel wall hydraulic conductivity. Increasing sprout length, increasing wall hydraulic conductivity, and decreasing perivascular space width increased shear stress magnitude. Wall shear stress magnitude within the lumen ranged from 0.015 to 0.55 dyne/cm
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- 2021
18. Mechanisms Underlying the Altered Bioenergetics of Aged Brain Microvasculature
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Lahari Kolli, Ricardo Mostany, Venkata N. Sure, Wesley R. Evans, Siva S.V.P. Sakamuri, Walter L. Murfee, and Prasad V. G. Katakam
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Bioenergetics ,Genetics ,Biology ,Molecular Biology ,Biochemistry ,Neuroscience ,Biotechnology - Published
- 2021
19. Computational Evaluation of Wall Shear Stress Experienced by Endothelial Tip Cells along Capillary Sprouts
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Julian Rey, Maximillian Rozenblum, Camille Rodriguez, Malisa Sarntinoranont, Nien-Wen Hu, and Walter L. Murfee
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Materials science ,Capillary action ,Genetics ,Shear stress ,Composite material ,Molecular Biology ,Biochemistry ,Biotechnology - Published
- 2021
20. Lymphatic Vessel Network Structure and Physiology
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Shaquria P. Adderley, Ying Yang, Jerome W. Breslin, Joshua P. Scallan, Richard S. Sweat, and Walter L. Murfee
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0301 basic medicine ,Physiology ,Biology ,Article ,Lymphangiogenesis ,Lymphatic System ,03 medical and health sciences ,030104 developmental biology ,Lymphatic system ,medicine.anatomical_structure ,Immunity ,Extracellular fluid ,Lymphatic vessel ,medicine ,Animals ,Homeostasis ,Humans ,Lymph ,Organ Specificity - Abstract
The lymphatic system is comprised of a network of vessels interrelated with lymphoid tissue, which has the holistic function to maintain the local physiologic environment for every cell in all tissues of the body. The lymphatic system maintains extracellular fluid homeostasis favorable for optimal tissue function, removing substances that arise due to metabolism or cell death, and optimizing immunity against bacteria, viruses, parasites, and other antigens. This article provides a comprehensive review of important findings over the past century along with recent advances in the understanding of the anatomy and physiology of lymphatic vessels, including tissue/organ specificity, development, mechanisms of lymph formation and transport, lymphangiogenesis, and the roles of lymphatics in disease. © 2019 American Physiological Society. Compr Physiol 9:207-299, 2019.
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- 2018
21. Understanding angiogenesis during aging: opportunities for discoveries and new models
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Walter L. Murfee, Ariana D. Suarez-Martinez, and Nicholas A. Hodges
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0301 basic medicine ,Aging ,medicine.medical_specialty ,Physiology ,Angiogenesis ,Neovascularization, Physiologic ,Review ,030204 cardiovascular system & hematology ,Microcirculation ,Tissue Culture Techniques ,03 medical and health sciences ,0302 clinical medicine ,Physiology (medical) ,Internal medicine ,Animals ,Humans ,Medicine ,Myocardial infarction ,Stroke ,Neovascularization, Pathologic ,business.industry ,medicine.disease ,Multiple pathologies ,Endothelial stem cell ,030104 developmental biology ,medicine.anatomical_structure ,Microvascular Network ,Microvessels ,Cardiology ,Pericyte ,Pericytes ,business - Abstract
Microvascular network growth and remodeling are common denominators for most age-related pathologies. For multiple pathologies (myocardial infarction, stroke, hypertension), promoting microvascular growth, termed angiogenesis, would be beneficial. For others (cancer, retinopathies, rheumatoid arthritis), blocking angiogenesis would be desirable. Most therapeutic strategies, however, are motivated based on studies using adult animal models. This approach is problematic and does not account for the impaired angiogenesis or the inherent network structure changes that might result from age. Considering the common conception that angiogenesis is impaired with age, a need exists to identify the causes and mechanisms of angiogenesis in aged scenarios and for new tools to enable comparison of aged versus adult responses to therapy. The objective of this article is to introduce opportunities for advancing our understanding of angiogenesis in aging through the discovery of novel cell changes along aged microvascular networks and the development of novel ex vivo models.
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- 2018
22. Clinical perspectives on the microcirculation
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Fong Lam, Asher A. Mendelson, Walter L. Murfee, and Shayn M. Peirce
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Physiology ,business.industry ,Microcirculation ,Physiology (medical) ,Medicine ,Translational research ,Cardiology and Cardiovascular Medicine ,business ,Molecular Biology ,Neuroscience - Published
- 2021
23. Biomimetic Models of the Microcirculation for Scientific Discovery and Therapeutic Testing
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Robert M. Dolan, Malisa Sarntinoranont, Cheryl Gomillion, Ariana D. Suarez-Martinez, Christopher R. Anderson, Shayn M. Peirce, Peter S. McFetridge, Jessica M. Motherwell, Walter L. Murfee, and Nicholas A. Hodges
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Scientific discovery ,Biology ,Neuroscience ,Microcirculation - Published
- 2021
24. Microvascular dysfunction and kidney disease: Challenges and opportunities?
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Ariana D. Suarez-Martinez, Suraj Krishnan, Pooneh Bagher, Ruisheng Liu, Rajesh Mohandas, Walter L. Murfee, and Anjelica L. Gonzalez
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Pathology ,medicine.medical_specialty ,Physiology ,Renal function ,030204 cardiovascular system & hematology ,Kidney ,urologic and male genital diseases ,Article ,Microcirculation ,03 medical and health sciences ,0302 clinical medicine ,Fibrosis ,Physiology (medical) ,Humans ,Medicine ,Molecular Biology ,business.industry ,Blood flow ,medicine.disease ,medicine.anatomical_structure ,Renal blood flow ,Microvessels ,Kidney Diseases ,Pericyte ,Cardiology and Cardiovascular Medicine ,business ,030217 neurology & neurosurgery ,Kidney disease - Abstract
Kidneys are highly vascular organs that despite their relatively small size receive 20% of the cardiac output. The highly intricate, delicately organized structure of renal microcirculation is essential to enable renal function and glomerular filtration rate through the local modulation of renal blood flow and intraglomerular pressure. Not surprisingly, the dysregulation of blood flow within the microvessels (abnormal vasoreactivity), fibrosis driven by disordered vascular-renal cross talk, or the loss of renal microvasculature (rarefaction) is associated with kidney disease. In addition, kidney disease can cause microcirculatory dysfunction in distant organs such as the heart and brain, mediated by mechanisms that remain to be elucidated. The objective of this review is to highlight the role of renal microvasculature in kidney disease. The overview will outline the impetus to study renal microvasculature, the bidirectional relationship between kidney disease and microvascular dysfunction, the key pathways driving microvascular diseases such as vasoreactivity, the cell dynamics coordinating fibrosis, and vessel rarefaction. Finally, we will also briefly highlight new therapies targeting the renal microvasculature to improve renal function.
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- 2020
25. Bioprinting on Live Tissue for Investigating Cancer Cell Dynamics
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Kevin Bauer, Zachary R. Wakefield, Walter L. Murfee, Marc Sole-Gras, Yong Huang, Samantha S. Dykes, Dima Majbour, Matthew E. Burow, Ariana D. Suarez-Martinez, Dietmar W. Siemann, Christine Pampo, and Angela Bundy
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Angiogenesis ,0206 medical engineering ,Biomedical Engineering ,Bioengineering ,02 engineering and technology ,Biology ,Biochemistry ,Biomaterials ,03 medical and health sciences ,Tissue culture ,Mice ,Neoplasms ,Animals ,Inkjet printing ,030304 developmental biology ,0303 health sciences ,Tumor microenvironment ,Special Issue on Oncology and Tissue Engineering ,Neovascularization, Pathologic ,Tissue Engineering ,Dynamics (mechanics) ,Bioprinting ,020601 biomedical engineering ,Cancer cell ,Microvessels ,Printing, Three-Dimensional ,Cancer research ,Breast cancer cells - Abstract
A challenge in cancer research is the lack of physiologically responsive in vitro models that enable tracking of cancer cells in tissue-like environments. A model that enables real-time investigation of cancer cell migration, fate, and function during angiogenesis does not exist. Current models, such as 2D or 3D in vitro culturing, can contain multiple cell types, but they do not incorporate the complexity of intact microvascular networks. The objective of this study was to establish a tumor microvasculature model by demonstrating the feasibility of bioprinting cancer cells onto excised mouse tissue. Inkjet-printed DiI(+) breast cancer cells on mesometrium tissues from C57Bl/6 mice demonstrated cancer cells' motility and proliferation through time-lapse imaging. Colocalization of DAPI(+) nuclei confirmed that DiI(+) cancer cells remained intact postprinting. Printed DiI(+) 4T1 cells also remained viable after printing on Day 0 and after culture on Day 5. Time-lapse imaging over 5 days enabled tracking of cell migration and proliferation. The number of cells and cell area were significantly increased over time. After culture, cancer cell clusters were colocalized with angiogenic microvessels. The number of vascular islands, defined as disconnected endothelial cell segments, was increased for tissues with bioprinted cancer cells, which suggests that the early stages of angiogenesis were influenced by the presence of cancer cells. Bioprinting cathepsin L knockdown 4T1 cancer cells on wild-type tissues or nontarget 4T1 cells on NG2 knockout tissues served to validate the use of the model for probing tumor cell versus microenvironment changes. These results establish the potential for bioprinting cancer cells onto live mouse tissues to investigate cancer microvascular dynamics within a physiologically relevant microenvironment. IMPACT STATEMENT: To keep advancing the cancer biology field, tissue engineering has been focusing on developing in vitro tumor biomimetic models that more closely resemble the native microenvironment. We introduce a novel methodology of bioprinting exogenous cancer cells onto mouse tissue that contains multiple cells and systems within native physiology to investigate cancer cell migration and interactions with nearby microvascular networks. This study corroborates the manipulation of different exogenous cells and host microenvironments that impact cancer cell dynamics in a physiologically relevant tissue. Overall, it is a new approach for delineating the effects of the microenvironment on cancer cells and vice versa.
- Published
- 2020
26. A clinical perspective on adipose-derived cell therapy for enhancing microvascular health and function: Implications and applications for reconstructive surgery
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V Morgan Jones, Nicholas A. Hodges, Ramon Llull, Walter L. Murfee, Adam J. Katz, and Ariana D. Suarez-Martinez
- Subjects
0301 basic medicine ,Stromal cell ,Physiology ,Angiogenesis ,Cell- and Tissue-Based Therapy ,Adipose tissue ,030204 cardiovascular system & hematology ,Bioinformatics ,03 medical and health sciences ,0302 clinical medicine ,Vasculogenesis ,Physiology (medical) ,Adipocytes ,Medicine ,Molecular Biology ,Sprouting angiogenesis ,Stromal Vascular Fraction ,business.industry ,Microcirculation ,Mesenchymal stem cell ,Stromal vascular fraction ,Plastic Surgery Procedures ,030104 developmental biology ,Adipose Tissue ,Cardiology and Cardiovascular Medicine ,business ,Wound healing - Abstract
Restoration of form and function requires apposition of tissues in the form of flaps to reconstitute local perfusion. Successful reconstruction relies on flap survival and its integration with the recipient bed. The flap's precariously perfused hypoxic areas undergo adaptive microvascular changes both internally and in connection with the recipient bed. A cell-mediated, coordinated response to hypoxia drives these adaptive processes, restoring a tissue's normoxic homeostasis via de novo vasculogenesis, sprouting angiogenesis, and stabilizing arterialization. As cells exert prolonged and coordinated effects on site, their use as biological agents merit translational consideration of sourcing angio-competent cells and delivering them to territories enduring microcirculatory acclimatization. Angio-competent cells abound in adipose tissue: a reliable, accessible, and expendable source of adipose-derived cells (ADC). When subject to enzymatic digestion and centrifugation, adipose tissue separates its various ADC: A subset of buoyant oil-dense adipocytes (the tissue's parenchymal component) accumulates on a supra-natant layer, whereas the mesenchymal component remains in the infra-natant sediment, containing the tissue's stromal vascular fraction (SVF), where angio-component cells abound. The SVF can be further manipulated, selected, or culture expanded into more specific stromal subsets (herein defined as adipose stromal cells, ASC). While promising clinical applications for ADC await clinical proof and regulatory authorization, basic science investigation is needed to elucidate the specific ADC mechanisms that influence microvascular growth, remodeling, and function following flap surgery. The objective of this article is to share the clinical perspectives of reconstructive plastic surgeons regarding the use of ADC-based therapies to help with flap tissue integration, revascularization, and wound healing. Specifically, the focus will be on considering the potential for ADC as therapeutic agents and how their clinical application motivates basic science opportunities.
- Published
- 2020
27. Pericyte Bridges in Homeostasis and Hyperglycemia
- Author
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Shayn M. Peirce, Paul A. Yates, Gary Owens, John Chappell, Walter L. Murfee, Molly Kelly-Goss, Remi Prince, Kathleen Fitzgerald, Natasha Sheybani, Corbin Mathews, Richard W. Doty, H. Clifton Ray, Bruce A. Corliss, and Ada Admin
- Abstract
Diabetic retinopathy is a potentially blinding eye disease that threatens the vision of a ninth of diabetic patients. Progression of the disease has long been attributed to an initial dropout of pericytes that enwrap the retinal microvasculature. Revealed through retinal vascular digests, a subsequent increase in basement membrane bridges is observed. Using cell-specific markers, we demonstrate that pericytes rather than endothelial cells colocalize with these bridges. We show that the density of bridges transiently increases with elevation of Ang-2, PDGF-BB, and blood sugar, is rapidly reversed on a time scale of days, and often associated with a pericyte cell body located off-vessel. Cell-specific knockout of KLF4 in pericytes fully replicates this phenotype. In vivo imaging of limbal vessels demonstrates pericyte migration off-vessel, with rapid pericyte filopodial-like process formation between adjacent vessels. Accounting for off-vessel and on-vessel pericytes, we observe no pericyte loss relative to non-diabetic control retina. These findings reveal the possibility that pericyte perturbations in location and process formation may play a role in the development of pathological vascular remodeling in diabetic retinopathy.
- Published
- 2020
28. Cover Image
- Author
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Mohammad S. Azimi, Jessica M. Motherwell, Nicholas A. Hodges, Garret R. Rittenhouse, Dima Majbour, Stacey L. Porvasnik, Christine E. Schmidt, and Walter L. Murfee
- Subjects
Physiology ,Physiology (medical) ,Cardiology and Cardiovascular Medicine ,Molecular Biology - Published
- 2020
29. A novel high-throughput assay for respiration in isolated brain microvessels reveals impaired mitochondrial function in the aged mice
- Author
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Jared A. Sperling, Siva S.V.P. Sakamuri, David W. Busija, Wesley R. Evans, Ivan Merdzo, Venkata N. Sure, Prasad V. G. Katakam, Walter L. Murfee, and Ricardo Mostany
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Male ,0301 basic medicine ,Aging ,Cell Respiration ,In Vitro Techniques ,Mitochondrion ,Sensitivity and Specificity ,Mice ,03 medical and health sciences ,Cerebral circulation ,Adenosine Triphosphate ,Oxygen Consumption ,0302 clinical medicine ,Reference Values ,Respiration ,Methods ,Animals ,Premovement neuronal activity ,Medicine ,Respiratory system ,business.industry ,Cerebral Arteries ,Isolated brain ,High-Throughput Screening Assays ,Mitochondria ,Mice, Inbred C57BL ,030104 developmental biology ,Cerebral blood flow ,Cerebrovascular Circulation ,Microvessels ,Models, Animal ,Geriatrics and Gerontology ,business ,Neuroscience ,030217 neurology & neurosurgery ,Ex vivo - Abstract
Cerebral blood flow (CBF) is uniquely regulated by the anatomical design of the cerebral vasculature as well as through neurovascular coupling. The process of directing the CBF to meet the energy demands of neuronal activity is referred to as neurovascular coupling. Microvasculature in the brain constitutes the critical component of the neurovascular coupling. Mitochondria provide the majority of ATP to meet the high-energy demand of the brain. Impairment of mitochondrial function plays a central role in several age-related diseases such as hypertension, ischemic brain injury, Alzheimer’s disease, and Parkinson disease. Interestingly, microvessels and small arteries of the brain have been the focus of the studies implicating the vascular mechanisms in several age-related neurological diseases. However, the role of microvascular mitochondrial dysfunction in age-related diseases remains unexplored. To date, high-throughput assay for measuring mitochondrial respiration in microvessels is lacking. The current study presents a novel method to measure mitochondrial respiratory parameters in freshly isolated microvessels from mouse brain ex vivo using Seahorse XFe24 Analyzer. We validated the method by demonstrating impairments of mitochondrial respiration in cerebral microvessels isolated from old mice compared to the young mice. Thus, application of mitochondrial respiration studies in microvessels will help identify novel vascular mechanisms underlying a variety of age-related neurological diseases.
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- 2018
30. Lymphatic‐to‐blood vessel transition in adult microvascular networks: A discovery made possible by a top‐down approach to biomimetic model development
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Nicholas A. Hodges, Christine E. Schmidt, Dima Majbour, Mohammad S. Azimi, Garret R. Rittenhouse, Walter L. Murfee, Jessica M. Motherwell, and Stacey L. Porvasnik
- Subjects
Male ,Pathology ,medicine.medical_specialty ,Physiology ,Angiogenesis ,Vascular Remodeling ,030204 cardiovascular system & hematology ,Biology ,Article ,Microcirculation ,03 medical and health sciences ,Tissue culture ,0302 clinical medicine ,Physiology (medical) ,medicine ,Animals ,Rats, Wistar ,Molecular Biology ,Lymphatic Vessels ,Models, Cardiovascular ,Endothelial Cells ,Capillaries ,Rats ,Lymphangiogenesis ,Endothelial stem cell ,Lymphatic system ,medicine.anatomical_structure ,Podoplanin ,cardiovascular system ,Cardiology and Cardiovascular Medicine ,030217 neurology & neurosurgery ,Blood vessel - Abstract
Objective Emerging areas of vascular biology focus on lymphatic/blood vessel mispatterning and the regulation of endothelial cell identity. However, a fundamental question remains unanswered: Can lymphatic vessels become blood vessels in adult tissues? Leveraging a novel tissue culture model, the objective of this study was to track lymphatic endothelial cell fate over the time course of adult microvascular network remodeling. Methods Cultured adult Wistar rat mesenteric tissues were labeled with BSI-lectin and time-lapse images were captured over five days of serum-stimulated remodeling. Additionally, rat mesenteric tissues on day 0 and day 3 and 5 post-culture were labeled for PECAM + LYVE-1 or PECAM + podoplanin. Results Cultured networks were characterized by increases in blood capillary sprouting, lymphatic sprouting, and the number of lymphatic/blood vessel connections. Comparison of images from the same network regions identified incorporation of lymphatic vessels into blood vessels. Mosaic lymphatic/blood vessels contained lymphatic marker positive and negative endothelial cells. Conclusions Our results reveal the ability for lymphatic vessels to transition into blood vessels in adult microvascular networks and discover a new paradigm for investigating lymphatic/blood endothelial cell dynamics during microvascular remodeling.
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- 2019
31. Endothelial dysfunction and angiogenesis impairment in the ageing vasculature
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Tamas Kiss, Courtney T. Griffin, Zoltan Ungvari, Stefano Tarantini, Cory B. Giles, Walter L. Murfee, Anna Csiszar, Pal Pacher, and Jonathan D. Wren
- Subjects
0301 basic medicine ,Aging ,Endothelium ,Angiogenesis ,Neovascularization, Physiologic ,Bioinformatics ,Article ,Microcirculation ,Mice ,03 medical and health sciences ,Animals ,Humans ,Medicine ,Vascular Diseases ,Endothelial dysfunction ,Pathological ,business.industry ,Mechanism (biology) ,medicine.disease ,Rats ,030104 developmental biology ,medicine.anatomical_structure ,Ageing ,Dilator ,Endothelium, Vascular ,Cardiology and Cardiovascular Medicine ,business - Abstract
Ageing is the main risk factor for the development of cardiovascular diseases. A central mechanism by which ageing promotes vascular pathologies is compromising endothelial health. The age-related attenuation of endothelium-dependent dilator responses (endothelial dysfunction) associated with impairment of angiogenic processes and the subsequent pathological remodelling of the microcirculation contribute to compromised tissue perfusion and exacerbate functional decline in older individuals. This Review focuses on cellular, molecular, and functional changes that occur in the endothelium during ageing. We explore the links between oxidative and nitrative stress and the conserved molecular pathways affecting endothelial dysfunction and impaired angiogenesis during ageing. We also speculate on how these pathological processes could be therapeutically targeted. An improved understanding of endothelial biology in older patients is crucial for all cardiologists because maintenance of a competently functioning endothelium is critical for adequate tissue perfusion and long-term cardiac health.
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- 2018
32. Aging is associated with impaired angiogenesis, but normal microvascular network structure, in the rat mesentery
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Scott A. Stewart, Leann Myers, Ariana D. Suarez-Martinez, Hope E. Burks, Melody Baddoo, Richard S. Sweat, Lee O. Chedister, David C. Sloas, Malwina Czarny-Ratajczak, James R. Eastwood, Mohammad S. Azimi, and Walter L. Murfee
- Subjects
Male ,0301 basic medicine ,Aging ,Pathology ,medicine.medical_specialty ,Physiology ,Angiogenesis ,Neovascularization, Physiologic ,Rat Mesentery ,Biology ,Microcirculation ,03 medical and health sciences ,Vessel density ,Physiology (medical) ,medicine ,Animals ,p-Methoxy-N-methylphenethylamine ,Mesentery ,Mast Cells ,Platelet endothelial cell adhesion molecule-1 ,Muscle, Skeletal ,Sequence Analysis, RNA ,Models, Cardiovascular ,Computational Biology ,Anatomy ,Models, Theoretical ,Immunohistochemistry ,Rats, Inbred F344 ,Capillaries ,Rats ,Platelet Endothelial Cell Adhesion Molecule-1 ,030104 developmental biology ,medicine.anatomical_structure ,Microvascular Network ,Microvessels ,Vascular Resistance ,Transcriptome ,Cardiology and Cardiovascular Medicine ,Research Article - Abstract
A big problem associated with aging is thought to be impaired microvascular growth or angiogenesis. However, to link the evidence for impaired angiogenesis to microvascular dysfunction in aged tissues, we must compare adult vs. aged microvascular networks in unstimulated scenarios. The objective of this study was to test the hypothesis that aged microvascular networks are characterized by both fewer vessels and the impaired ability to undergo angiogenesis. Mesentery tissues from adult (9-mo) and aged (24-mo) male Fischer 344 rats were harvested and immunolabeled for platelet/endothelial cell adhesion molecule (an endothelial cell marker) according to two scenarios: unstimulated and stimulated. For unstimulated groups, tissues harvested from adult and aged rats were compared. For stimulated groups, tissues were harvested 3 or 10 days after compound 48/80-induced mast cell degranulation stimulation. Unstimulated aged microvascular networks displayed larger mean vascular area per tissue area compared with the unstimulated adult networks. The lack of a decrease in vessel density was supported at the gene expression level with RNA-Seq analysis and with comparison of vessel densities in soleus muscle. Following stimulation, capillary sprouting and vessel density were impaired in aged networks at 3 and 10 days, respectively. Our results suggest that aging associated with impaired angiogenesis mechanisms might not influence normal microvascular function, since unstimulated aged microvascular networks can display a “normal adult-like” vessel density and architecture. NEW & NOTEWORTHY Using a multidimensional approach, we present evidence supporting that aged microvascular networks display vessel density and patterning similar to adult networks despite also being characterized by a decreased capacity to undergo angiogenesis. Thus, vessel loss is not necessarily a characteristic of aging.
- Published
- 2017
33. Linking lymphatic function to disease
- Author
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Jerome W. Breslin and Walter L. Murfee
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Pathology ,medicine.medical_specialty ,Contraction (grammar) ,Physiology ,Chemistry ,Hypertrichosis ,Muscle, Smooth ,Sulfonylurea Receptors ,Article ,Mice, Inbred C57BL ,Mice ,Adenosine Triphosphate ,medicine.anatomical_structure ,KATP Channels ,Gain of Function Mutation ,cardiovascular system ,Lymphatic vessel ,medicine ,Animals ,Humans ,Lymphatic function ,Ion channel ,Lymphatic Vessels - Abstract
This study aimed to understand the functional expression of K(ATP) channel subunits in distinct lymphatic cell types, and assess the consequences of altered K(ATP) channel activity on lymphatic pump function. K(ATP) channel subunits Kir6.1 and SUR2B were expressed in mouse lymphatic muscle by PCR, but only Kir6.1 was expressed in lymphatic endothelium. Spontaneous contractions of popliteal lymphatics from WT (C57BL/6J) mice, assessed by pressure myography, were very sensitive to inhibition by the SUR2-specific K(ATP) channel activator pinacidil, which hyperpolarized both mouse and human lymphatic smooth muscle (LSM). In vessels from mice with deletion of Kir6.1 (Kir6.1(−/−)) or SUR2 (SUR2[STOP]) subunits, contractile parameters were not significantly different from those of WT vessels, suggesting that basal K(ATP) channel activity in LSM is not an essential component of the lymphatic pacemaker, nor exerts a strong influence over contractile strength. However, these vessels were >100-fold less sensitive than WT vessels to pinacidil. Smooth muscle-specific expression of a Kir6.1 gain-of-function (GoF) subunit resulted in severely impaired lymphatic contractions and hyperpolarized LSM. Membrane potential and contractile activity was partially restored by the K(ATP) channel inhibitor, glibenclamide. In contrast, lymphatic endothelium-specific expression of Kir6.1 GoF subunits had negligible effects on lymphatic contraction frequency or amplitude. Our results demonstrate a high sensitivity of lymphatic contractility to K(ATP) channel activators through activation of Kir6.1/SUR2-dependent channels in LSM. In addition, they offer an explanation for the lymphedema observed in patients with Cantú Syndrome, a disorder caused by gain-of-function mutations in genes encoding Kir6.1/SUR2.
- Published
- 2020
34. Bioreactor System to Perfuse Mesentery Microvascular Networks and Study Flow Effects During Angiogenesis
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Prasad V. G. Katakam, Jessica M. Motherwell, Walter L. Murfee, and Maximillian Rozenblum
- Subjects
Angiogenesis ,0206 medical engineering ,Biomedical Engineering ,Medicine (miscellaneous) ,Neovascularization, Physiologic ,Bioengineering ,02 engineering and technology ,Tissue Culture Techniques ,03 medical and health sciences ,Tissue culture ,Bioreactors ,Bioreactor ,medicine ,Animals ,Rats, Wistar ,Mesentery ,030304 developmental biology ,0303 health sciences ,Chemistry ,020601 biomedical engineering ,Rats ,Methods Articles ,medicine.anatomical_structure ,Flow (mathematics) ,Microvessels ,Biomedical engineering - Abstract
A challenge for engineering models of angiogenesis is mimicking the physiological complexity of real microvascular networks. Utilizing an alternative top-down tissue culture approach, our laboratory developed the rat mesentery culture model as an ex vivo platform for investigating the multicellular dynamics involved during angiogenesis within an intact microvascular network. The objective of this study was to introduce physiologically relevant microvascular perfusion in cultured rat mesentery tissues and demonstrate its effect on angiogenesis. Adult male Wistar rat mesenteric tissues were harvested along with the main feeding artery and vein, and then transferred to a custom-designed biochamber for perfusion. The main feeding artery was cannulated with a 30G needle and secured in place with 7–0 suture. Single-pass perfusion was accomplished using a peristaltic pump in series with the biochamber placed inside an incubator set to standard culture conditions (37°C and 5% CO(2)). Flow passed through the vasculature and drained out of the venous side to be collected in a waste reservoir. Tissues were cultured for 48 h with perfusion in the biochamber (Perfused) in serum-supplemented media to stimulate angiogenesis. Control tissues were cultured in biochambers without perfusion (Static). Injection with FITC-albumin through the cannulated artery identified the lumens of vessels across the hierarchy of intact microvascular networks and confirmed successful perfusion. Labeling with BSI-lectin identified endothelial cells along microvascular networks and confirmed perfused tissues undergo angiogenesis after 48 h in culture, characterized by an increase in capillary sprouting. The presence of physiologic levels of capillary fluid velocities and associated shear stresses attenuated the angiogenic response compared to static controls. These results demonstrate the effect of perfusion on angiogenesis and establishes the novelty of the rat mesentery culture model as an experimental platform that incorporates perfusion with real microvascular networks in an ex vivo environment. IMPACT STATEMENT: Microvascular remodeling, or angiogenesis, plays a central role in multiple pathological conditions, including cancer, diabetes, and ischemia. Tissue-engineered in vitro models have emerged as tools to elucidate the mechanisms that drive the angiogenic process. However, a major challenge with model development is recapitulating the physiological complexity of real microvascular networks, including incorporation of the entire vascular tree and hemodynamics. This study establishes a bioreactor system that incorporates real microvascular networks with physiological flow as a novel ex vivo tissue culture model, thereby providing a platform to evaluate angiogenesis in a physiologically relevant environment.
- Published
- 2019
35. Pericyte Bridges in Homeostasis and Hyperglycemia: Reconsidering Pericyte Dropout and Microvascular Structures
- Author
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Kathleen Fitzgerald, Richard Doty, John C. Chappell, Gary K. Owens, Shayn M. Peirce, Remi Prince, Natasha D. Sheybani, Bruce A. Corliss, H. Clifton Ray, Molly R. Kelly-Goss, Paul A. Yates, Corbin Mathews, and Walter L. Murfee
- Subjects
Basement membrane ,0303 health sciences ,Pathology ,medicine.medical_specialty ,Cell type ,Chemistry ,Retinal ,Diabetic retinopathy ,medicine.disease ,Pathogenesis ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,medicine.anatomical_structure ,KLF4 ,medicine ,Pericyte ,030217 neurology & neurosurgery ,Homeostasis ,030304 developmental biology - Abstract
Diabetic retinopathy threatens the vision of a third of diabetic patients. Progression of the disease is attributed to the dropout of pericytes, a cell type that enwraps and stabilizes the microvasculature. In tandem with this presumptive pericyte dropout, there is enriched formation of structures assumed to be remnants of collapsed or regressed vessels, previously classified as acellular capillaries, string vessels, and basement membrane bridges. Instead of endothelial cells, we show that pericytes colocalize with basement membrane bridges, and both bridging structures are enriched by cell-specific knockout of KLF4 and reversibly enriched with elevation of Ang-2, PDGF-BB, and blood sugar. Our data suggests that pericyte counts from retinal digests have misclassified pericyte bridges as endothelial structures and have exaggerated the role of pericyte loss in DR progression. In vivo imaging of corneal limbal vessels demonstrates pericyte migration off-vessel, implicating pericyte movement in formation of pericyte bridges and pathogenesis of diabetic retinopathy.
- Published
- 2019
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36. Pericyte Bridges in Homeostasis and Hyperglycemia
- Author
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Paul A. Yates, Corbin Mathews, Kathleen Fitzgerald, H. Clifton Ray, Gary K. Owens, Shayn M. Peirce, Bruce A. Corliss, Walter L. Murfee, Remi Prince, Richard Doty, Natasha D. Sheybani, John C. Chappell, and Molly R. Kelly-Goss
- Subjects
0301 basic medicine ,Collagen Type IV ,Endocrinology, Diabetes and Metabolism ,Cell ,Becaplermin ,Kruppel-Like Transcription Factors ,030209 endocrinology & metabolism ,Biology ,Pathophysiology ,Streptozocin ,Diabetes Mellitus, Experimental ,03 medical and health sciences ,chemistry.chemical_compound ,Kruppel-Like Factor 4 ,Mice ,0302 clinical medicine ,Diabetes mellitus ,Internal Medicine ,medicine ,Animals ,Homeostasis ,Insulin ,Antigens ,Basement membrane ,Retina ,Diabetic Retinopathy ,Myosin Heavy Chains ,Retinal ,Diabetic retinopathy ,Ribonuclease, Pancreatic ,medicine.disease ,Cell biology ,Mice, Inbred C57BL ,Platelet Endothelial Cell Adhesion Molecule-1 ,030104 developmental biology ,medicine.anatomical_structure ,chemistry ,Hyperglycemia ,Proteoglycans ,Pericyte ,Pericytes - Abstract
Diabetic retinopathy is a potentially blinding eye disease that threatens the vision of one-ninth of patients with diabetes. Progression of the disease has long been attributed to an initial dropout of pericytes that enwrap the retinal microvasculature. Revealed through retinal vascular digests, a subsequent increase in basement membrane bridges was also observed. Using cell-specific markers, we demonstrate that pericytes rather than endothelial cells colocalize with these bridges. We show that the density of bridges transiently increases with elevation of Ang-2, PDGF-BB, and blood glucose; is rapidly reversed on a timescale of days; and is often associated with a pericyte cell body located off vessel. Cell-specific knockout of KLF4 in pericytes fully replicates this phenotype. In vivo imaging of limbal vessels demonstrates pericyte migration off vessel, with rapid pericyte filopodial-like process formation between adjacent vessels. Accounting for off-vessel and on-vessel pericytes, we observed no pericyte loss relative to nondiabetic control retina. These findings reveal the possibility that pericyte perturbations in location and process formation may play a role in the development of pathological vascular remodeling in diabetic retinopathy.
- Published
- 2019
37. Emerging topics in microvascular research: Advancing our understanding by interdisciplinary exploration
- Author
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Phoebe A. Stapleton, Joshua T. Butcher, and Walter L. Murfee
- Subjects
Engineering ,Biomedical Research ,Physiology ,business.industry ,emerging topics and microcirculation ,Microcirculation ,030204 cardiovascular system & hematology ,uteroplacental ,bone ,03 medical and health sciences ,0302 clinical medicine ,Editorial ,Physiology (medical) ,pericyte ,Microvessels ,Animals ,Humans ,Engineering ethics ,revascularization ,Cardiology and Cardiovascular Medicine ,business ,Molecular Biology ,microfluidic devices ,030217 neurology & neurosurgery - Abstract
Historically, major advances in microvascular research have been made by integrating physiology and bioengineering approaches. This Special Topics Issue focuses on providing a spotlight on emerging areas of microvascular research, showcasing how interdisciplinary collaborations and application of novel techniques can impact our understanding of tissue‐specific microvascular remodeling by integrating cell behaviors across scales. The authors in this issue investigate pericyte physiology, perturbations to uteroplacental blood flow, bone microvascular alterations in aging, molecular markers of revascularization, and microfluidic devices to mimic the lymphatic system. The articles highlight the continued importance of expanding our understanding of the microvascular system in health, and disease extends microvascular boundaries in the face of current paradigms, and illustrates how emerging leaders in the field are creating new scientific niches.
- Published
- 2019
38. Stromal Vascular Fraction Vasculogenesis, Vessel Incorporation, and Integration with Intact Angiogenic Microvascular Networks in an Ex Vivo Cultured Tissue Model
- Author
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Hulan Shang, Christine E. Schmidt, Nicholas A. Hodges, Walter L. Murfee, Stacy Porvasnik, Rocio R Guevara, and Adam J. Katz
- Subjects
Vasculogenesis ,Chemistry ,Tissue Model ,Genetics ,Stromal vascular fraction ,Molecular Biology ,Biochemistry ,Ex vivo ,Biotechnology ,Cell biology - Published
- 2019
39. Investigating Pericyte Dynamics during Angiogenesis in the Mouse Mesometrium Culture Model
- Author
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Jack Wang, Walter L. Murfee, and Ariana D. Suarez-Martinez
- Subjects
medicine.anatomical_structure ,Culture model ,Angiogenesis ,Dynamics (mechanics) ,Genetics ,medicine ,Pericyte ,Biology ,Molecular Biology ,Biochemistry ,Biotechnology ,Cell biology ,Mesometrium - Published
- 2019
40. An Ex Vivo Model for Investigating Transplanted Pancreatic Islet Vascular Integration
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Walter L. Murfee, Robert M. Dolan, Nicholas A. Hodges, and Edward A. Phelps
- Subjects
geography ,geography.geographical_feature_category ,Genetics ,Cancer research ,Biology ,Islet ,Molecular Biology ,Biochemistry ,Ex vivo ,Biotechnology - Published
- 2019
41. The maintenance of adult peripheral adult nerve and microvascular networks in the rat mesentery culture model
- Author
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Walter L. Murfee, Ryan W. Barr, and Nicholas A. Hodges
- Subjects
Male ,0301 basic medicine ,Pathology ,medicine.medical_specialty ,Angiogenesis ,Neovascularization, Physiologic ,Biology ,Calcitonin gene-related peptide ,Article ,Microcirculation ,03 medical and health sciences ,0302 clinical medicine ,Arteriole ,medicine.artery ,medicine ,Animals ,Mesentery ,Peripheral Nerves ,Rats, Wistar ,Tyrosine hydroxylase ,General Neuroscience ,Neurogenesis ,In vitro ,Rats ,030104 developmental biology ,Microvessels ,030217 neurology & neurosurgery ,Ex vivo - Abstract
Background Neurovascular patterning is an emerging area of microvascular research. While overlapping molecular signals highlight links between angiogenesis and neurogenesis, advancing our understanding is limited by a lack of in vitro models containing both systems. One potential model is the rat mesentery culture model, which our laboratory has recently introduced as an ex vivo tool to investigate cellular dynamics during angiogenesis in a microvascular network scenario. The objective of this study was to demonstrate the use of the rat mesentery culture model as an ex vivo platform for maintaining the spatiotemporal relationship between blood vessels and peripheral nerves during angiogenesis in adult microvascular networks. Methods Adult male Wistar rat mesenteric tissue windows were harvested, rinsed in sterile DPBS and medium and then cultured per group: 1) MEM alone and 2) NBM with NGF and 20 % FBS (nerve culture medium). On day 3 post culture tissues were labeled for endothelial (PECAM) and neural (class III β-tubulin, NG2, tyrosine hydroxylase, CGRP) markers. Results In MEM alone tissues nerve segment degeneration was supported by discontinuous nerve or absence of nerve marker labeling. Nerve presence at the arteriole level and capillary level was maintained for the nerve culture medium group compared to day 0, non-cultured control group (unstimulated). Comparison with existing methods and conclusions The results support the use of specific medium types to maintain nerve presence across cultured microvascular networks and implicates the rat mesentery culture model as a novel ex vivo tool for investigating neurovascular patterning in adult tissues.
- Published
- 2020
42. Abstract A23: A novel tumor microenvironment model that combines bioprinting and tissue culture to investigate cancer cell and microvascular interactions
- Author
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Kevin Bauer, Dietmar W. Siemann, Ariana D. Suarez-Martinez, Marc Sole-Gras, Walter L. Murfee, Samantha S. Dykes, Yong Huang, Arinola Lampejo, and Zachary R. Wakefield
- Subjects
0301 basic medicine ,Cancer Research ,Cell type ,Tumor microenvironment ,Cell ,Cancer ,Cell cycle ,medicine.disease ,Cell biology ,03 medical and health sciences ,chemistry.chemical_compound ,Tissue culture ,030104 developmental biology ,0302 clinical medicine ,medicine.anatomical_structure ,Oncology ,chemistry ,030220 oncology & carcinogenesis ,Cancer cell ,medicine ,DAPI - Abstract
A challenge in cancer research is the lack of a physiologically responsive in vitro model that allows for the investigation of cancer cells in a tissue-like environment. A model that enables real-time investigation of cancer cell migration, fate, and function during microvascular network growth does not currently exist. While current models such as 2D in vitro models or microfluidic systems incorporate real-time cell tracking and multiple cell types, they do not mimic the complexity of intact networks and tissue environments. The objective of this study was to establish a novel tumor-microvasculature model by demonstrating the feasibility of bioprinting cancer cells onto excised mouse mesometrium tissues. Prelabeled DiI mouse breast cancer (4T1) cells were inkjet-printed onto mouse mesometrium tissues. The cell ink for printing comprised 2% Na-alginate mixed in minimum essential media with 1% PenStrep (MEM) containing 15 million 4T1 cells. A single cancer cell spot per tissue was created by printing 10 drops of cell ink in the same location. MEM was added on top of tissue 30 seconds after printing and then incubated for 5 minutes before being plated into 6-well plates containing MEM supplemented with 20% serum. Tissues were cultured for 5 days, with media being changed every day. The spot of DiI+ cells was imaged every 24 hours to then quantify cell number and area for Day 0, 1, and 2. At Day 2 or 5, tissues were fixed in methanol and labeled with platelet endothelial cell adhesion molecule (PECAM), and E-cadherin, to identify endothelial cells and cancer cells, respectively. Co-localization of DAPI+ nuclei confirmed that DiI+ cells remained intact post-printing. Printed DiI+ 4T1 cells also remained viable after printing on Day 0 and after culture on Day 5. Time-lapse imaging over 5 days in culture enabled tracking of cell motility and proliferation. The number of cells (Day 0: 159 +/- 40, Day 1: 370 +/- 78, Day 2: 889 +/- 184, Day 5: 18,031 +/- 1,695) and cell area (Day 0: 0.72 +/- 0.19, Day 1: 1.89 +/- 0.33, Day 2: 2.92 +/- 0.44, Day 5: 5.93 +/- 0.75 mm2) were significantly increased over time. Moreover, a proliferation assay of anti-BrdU on Day 2 also highlighted that a subset of E-cadherin+ cells are in the S-phase of the cell cycle, contributing to the increase in cell number and cell area. Also, microvessels in the tissue were angiogenic evident by PECAM+ sprouts. These results corroborate that cancer cells are mobile and proliferative in this novel ex vivo model. Further, they demonstrate the potential for bioprinting cancer cells onto live, intact tissues to investigate cancer dynamics within a physiologically relevant microenvironment. Citation Format: Ariana D. Suarez-Martinez, Marc Sole-Gras, Samantha S. Dykes, Zachary R. Wakefield, Kevin Bauer, Arinola Lampejo, Dietmar W. Siemann, Yong Huang, Walter L. Murfee. A novel tumor microenvironment model that combines bioprinting and tissue culture to investigate cancer cell and microvascular interactions [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr A23.
- Published
- 2020
43. Estimation of Shear Stress Values Along Endothelial Tip Cells Past the Lumen of Capillary Sprouts
- Author
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Connor Courtney, Maximillian Rozenblum, Malisa Sarntinoranont, Nien-Wen Hu, and Walter L. Murfee
- Subjects
Materials science ,Capillary action ,Genetics ,Shear stress ,Molecular Biology ,Biochemistry ,Biotechnology ,Biomedical engineering ,Lumen (unit) - Published
- 2020
44. A Novel Tumor Microenvironment Model that Combines Bioprinting and Tissue Culture to Investigate Cancer Cell and Microvascular Interactions
- Author
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Kevin Bauer, Ariana D. Suarez-Martinez, Zachary R. Wakefield, Dietmar W. Siemann, Marc Sole-Gras, Yong Huang, Walter L. Murfee, Samantha S. Dykes, and Arinola Lampejo
- Subjects
Tumor microenvironment ,Tissue culture ,Cancer cell ,Genetics ,Cancer research ,Biology ,Molecular Biology ,Biochemistry ,Biotechnology - Published
- 2020
45. Angiogenesis is Not Impaired in Cultured Rat Mesenteric Microvascular Networks
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Nicholas A. Hodges and Walter L. Murfee
- Subjects
business.industry ,Angiogenesis ,Genetics ,Cancer research ,Medicine ,business ,Molecular Biology ,Biochemistry ,Biotechnology - Published
- 2018
46. Induction of Microvascular Network Growth in the Mouse Mesentery
- Author
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Walter L. Murfee, Ariana D. Suarez-Martinez, Joshua P. Scallan, Shayn Peirce-Cottler, and Brant E. Isakson
- Subjects
Mouse Mesentery ,Pathology ,medicine.medical_specialty ,Microvascular Network ,Genetics ,medicine ,Biology ,Molecular Biology ,Biochemistry ,Biotechnology - Published
- 2018
47. An Ex Vivo Platform for Studying Angiogenesis in Perfused Microvascular Networks
- Author
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Jessica M. Motherwell, Walter L. Murfee, and Prasad V. G. Katakam
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Angiogenesis ,Chemistry ,Genetics ,Molecular Biology ,Biochemistry ,Ex vivo ,Biotechnology ,Cell biology - Published
- 2018
48. Induction of microvascular network growth in the mouse mesentery
- Author
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Jack Wang, Karen M. Lounsbury, Walter L. Murfee, Shayn M. Peirce, Brant E. Isakson, Matthew Nice, Ariana D. Suarez-Martinez, and Joshua P. Scallan
- Subjects
0301 basic medicine ,Pathology ,medicine.medical_specialty ,food.ingredient ,Physiology ,medicine.medical_treatment ,Neovascularization, Physiologic ,Article ,Microcirculation ,03 medical and health sciences ,Mice ,food ,Physiology (medical) ,medicine ,Animals ,Plant Oils ,Mesentery ,Lymphangiogenesis ,Mesenteries ,Molecular Biology ,Saline ,Chemistry ,Sunflower oil ,Mice, Inbred C57BL ,Tamoxifen ,030104 developmental biology ,Lymphatic system ,Microvessels ,Peanut oil ,Cardiology and Cardiovascular Medicine ,Corn oil - Abstract
Objective Motivated by observations of mesenteries harvested from mice treated with tamoxifen dissolved in oil for inducible gene mutation studies, the objective of this study was to demonstrate that microvascular growth can be induced in the avascular mouse mesentery tissue. Methods C57BL/6 mice were administered an IP injection for five consecutive days of: saline, sunflower oil, tamoxifen dissolved in sunflower oil, corn oil, or peanut oil. Results Twenty-one days post-injection, zero tissues from saline group contained branching microvascular networks. In contrast, all tissues from the three oils and tamoxifen groups contained vascular networks with arterioles, venules, and capillaries. Smooth muscle cells and pericytes were present in their expected locations and wrapping morphologies. Significant increases in vascularized tissue area and vascular density were observed when compared to saline group, but sunflower oil and tamoxifen group were not significantly different. Vascularized tissues also contained LYVE-1-positive and Prox1-positive lymphatic networks, indicating that lymphangiogenesis was stimulated. When comparing the different oils, vascularized tissue area and vascular density of sunflower oil were significantly higher than corn and peanut oils. Conclusions These results provide novel evidence supporting that induction of microvascular network growth into the normally avascular mouse mesentery is possible.
- Published
- 2018
49. A Microcontroller Operated Device for the Generation of Liquid Extracts from Conventional Cigarette Smoke and Electronic Cigarette Aerosol
- Author
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Shusheng Wang, Andrew E Majeste, Chastain Anderson, Walter L. Murfee, and Rachael E Bokota
- Subjects
0301 basic medicine ,Computer science ,General Chemical Engineering ,Internet privacy ,Bioengineering ,Electronic Nicotine Delivery Systems ,Laboratory device ,General Biochemistry, Genetics and Molecular Biology ,law.invention ,03 medical and health sciences ,0302 clinical medicine ,law ,Cigarette smoke ,Humans ,030212 general & internal medicine ,Two sample ,Aerosols ,General Immunology and Microbiology ,business.industry ,General Neuroscience ,Smoking ,Regulatory policy ,Electronic Cigarette Use ,Microcontroller ,030104 developmental biology ,business ,Electronic cigarette ,Tobacco product - Abstract
Electronic cigarettes are the most popular tobacco product among middle and high schoolers and are the most popular alternative tobacco product among adults. High quality, reproducible research on the consequences of electronic cigarette use is essential for understanding emerging public health concerns and crafting evidence based regulatory policy. While a growing number of papers discuss electronic cigarettes, there is little consistency in methods across groups and very little consensus on results. Here, we describe a programmable laboratory device that can be used to create extracts of conventional cigarette smoke and electronic cigarette aerosol. This protocol details instructions for the assembly and operation of said device, and demonstrates the use of the generated extract in two sample applications: an in vitro cell viability assay and gas-chromatography mass-spectrometry. This method provides a tool for making direct comparisons between conventional cigarettes and electronic cigarettes, and is an accessible entry point into electronic cigarette research.
- Published
- 2018
50. Endothelial Cell Phenotypes are Maintained During Angiogenesis in Cultured Microvascular Networks
- Author
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Christopher R. Anderson, Jessica M. Motherwell, and Walter L. Murfee
- Subjects
0301 basic medicine ,CD36 Antigens ,Male ,Angiogenesis ,lcsh:Medicine ,Gene Expression ,Neovascularization, Physiologic ,Receptors, Cell Surface ,Biology ,Article ,Neovascularization ,Tissue Culture Techniques ,03 medical and health sciences ,0302 clinical medicine ,Tissue engineering ,In vivo ,medicine ,Animals ,Mesentery ,Rats, Wistar ,lcsh:Science ,Multidisciplinary ,Tissue Scaffolds ,lcsh:R ,Endothelial Cells ,Vascular Endothelial Growth Factor Receptor-2 ,Cell biology ,Culture Media ,Rats ,Endothelial stem cell ,030104 developmental biology ,medicine.anatomical_structure ,Phenotype ,Microvessels ,Pseudopodia ,lcsh:Q ,medicine.symptom ,030217 neurology & neurosurgery ,Ex vivo ,Biomarkers - Abstract
A challenge in tissue engineering biomimetic models for studying angiogenesis is building the physiological complexity of real microvascular networks. Our laboratory recently introduced the rat mesentery culture model as an ex vivo experimental platform for investigating multicellular dynamics involved in angiogenesis within intact microvascular networks. The objective of this study was to compare endothelial cell phenotypes along capillary sprouts in cultured ex vivo rat mesentery microvascular networks to in vivo endothelial cell phenotypes. For Day 3 (Ex Vivo) tissues, adult rat mesentery tissues were cultured for three days in media supplemented with 10% serum. For Day 3 (In Vivo) tissues, adult rats were anesthetized and the mesentery was exteriorized for twenty minutes to induce angiogenesis. Microvascular networks from Day 3 (Ex Vivo) and Day 3 (In Vivo) groups were angiogenic, characterized by an increase in vessel density, capillary sprouting, and identification of similar BrdU-positive endothelial cell distributions along sprouts. Endothelial cells in both groups extended pseudopodia at the distal edge of capillary sprouts and displayed similar endothelial cell UNC5b, VEGFR-2, and CD36 labeling patterns. The results from this study support the physiological relevance of the rat mesentery culture model and highlight its novelty as a biomimetic tool for angiogenesis research.
- Published
- 2017
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