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Summary

Abstract

Introduction

Protocol

Representative Results

Discussion

Acknowledgements

Materials

References

Biology

Isolation of Human Primary Valve Cells for In vitro Disease Modeling

Published: April 16th, 2021

DOI:

10.3791/62439

1Division of Cardiology, Department of Medicine, and the Pittsburgh Heart, Lung, and Blood Vascular Medicine Institute, University of Pittsburgh, 2Division of Cardiac Surgery, Department of Cardiothoracic Surgery, University of Pittsburgh and Heart and Vascular Institute, University of Pittsburgh Medical Center, 3Department of Bioengineering, University of Pittsburgh

This protocol describes the collection of human aortic valves extracted during surgical aortic valve replacement procedures or from cadaveric tissue, and the subsequent isolation, expansion, and characterization of patient specific primary valve endothelial and interstitial cells. Included are important details regarding the processes needed to ensure cell viability and phenotype specificity.

Calcific aortic valve disease (CAVD) is present in nearly a third of the elderly population. Thickening, stiffening, and calcification of the aortic valve causes aortic stenosis and contributes to heart failure and stroke. Disease pathogenesis is multifactorial, and stresses such as inflammation, extracellular matrix remodeling, turbulent flow, and mechanical stress and strain contribute to the osteogenic differentiation of valve endothelial and valve interstitial cells. However, the precise initiating factors that drive the osteogenic transition of a healthy cell into a calcifying cell are not fully defined. Further, the only current therapy for CAVD-induced aortic stenosis is aortic valve replacement, whereby the native valve is removed (surgical aortic valve replacement, SAVR) or a fully collapsible replacement valve is inserted via a catheter (transcatheter aortic valve replacement, TAVR). These surgical procedures come at a high cost and with serious risks; thus, identifying novel therapeutic targets for drug discovery is imperative. To that end, the present study develops a workflow where surgically removed tissues from patients and donor cadaver tissues are used to create patient-specific primary lines of valvular cells for in vitro disease modeling. This protocol introduces the utilization of a cold storage solution, commonly utilized in organ transplant, to reduce the damage caused by the often-lengthy procurement time between tissue excision and laboratory processing with the benefit of greatly stabilizing cells of the excised tissue. The results of the present study demonstrate that isolated valve cells retain their proliferative capacity and endothelial and interstitial phenotypes in culture upwards of several days after valve removal from the donor. Using these materials allows for the collection of control and CAVD cells, from which both control and disease cell lines are established.

Calcific aortic valve disease (CAVD) is a chronic pathology characterized by inflammation, fibrosis, and macrocalcification of aortic valve leaflets. Progressive remodeling and calcification of the leaflets (termed aortic sclerosis) can lead to the obstruction of blood flow (aortic stenosis) which contributes to stroke and leads to heart failure. Currently the only treatment for CAVD is surgical or transcatheter aortic valve replacement (SAVR and TAVR, respectively). There is no non-surgical option to halt or reverse CAVD progression, and without valve replacement, mortality rates approach 50% within 2-3 years1,2

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All patient samples are collected from individuals enrolled in studies approved by the institutional review board of the University of Pittsburgh in accordance with the Declaration of Helsinki. Cadaveric tissues obtained via the Center for Organ Recovery and Education (CORE) were approved by the University of Pittsburgh Committee for Oversight of Research and Clinical Training Involving Decedents (CORID).

1. Approval and safety

  1. Obtain Institutional Review Board (IRB) approval or an.......

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The above protocol outlines the steps necessary for the handling of human valve tissues and the isolation and establishment of viable cell lines from these tissues. Leaflets of the aortic valve are processed for paraffin embedding, snap frozen for long term storage for biochemical or genetic analysis and digested for the isolation of VECs and VICs (Figure 1). While surgical specimens will likely have a clinical diagnosis of aortic stenosis and may exhibit heavy nodules of calcification that .......

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Obtaining control and disease tissues from humans is critical for in vitro and ex vivo disease modeling; however, while one often speaks about the challenges of bridging the gap between bench to bedside, the reverse order - going from the surgical suite to the bench - is often just as daunting a gap. Essential for a basic scientist to obtain primary human tissue specimens is a collaboration with an invested surgeon scientist who has a team of nurses, surgical technicians, physician assistants, medical students and reside.......

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We would like to thank Jason Dobbins for insightful discussion and critical reading of this manuscript. We would like to acknowledge the Center for Organ Recovery and Education for their help and support and thank tissue donors and their families for making this study possible. All patient samples are collected from individuals enrolled in studies approved by the institutional review board of the University of Pittsburgh in accordance with the Declaration of Helsinki. Cadaveric tissues obtained via the Center for Organ Recovery and Education (CORE) were approved by the University of Pittsburgh Committee for Oversight of Research and Clinical Training Involving Deceden....

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Name Company Catalog Number Comments
0.45 μm filter Thermo Scientific 7211345 Preparing plate with collagen coating
10 cm cell culture plate Greiner Bio-One 664160 Cell culture/cell line expansion
10 mL serological pipet Fisher 14955234 VEC/VIC isolation, cell culture, cell line expansion
1000 μL filter tips VWR 76322-154 Cell culture/cell line expansion
10XL filter tips VWR 76322-132 Cell culture/cell line expansion
15 mL conical tubes Thermo Scientific 339650 Tissue storage, VIC/VEC isolation
16% paraformaldehyde aqueous solution Electron Microscopy Sciences 15710S Tissue and cell fixative
190 proof ethanol Decon 2801 Disinfection
1x DPBS: no calcium, no magnesium Gibco 14190250 Saline solution. VIC/VEC isolation
1x PBS Fisher BP2944100 Saline solution. Tissue preparation, VIC/VEC isolation
20 μL filter tips VWR 76322-134 Cell culture/cell line expansion
200 proof ethanol Decon 2701 Deparaffinizing tissue samples
2-propanol Fisher A416P 4 Making collagen coated plates
5 mL serological pipet Fisher 14955233 VEC/VIC isolation, cell culture, cell line expansion
50 mL conical tubes Thermo Scientific 339652 Tissue storage, VIC/VEC isolation
60 mm dish GenClone 25-260 VEC isolation
6-well cell culture plate Corning 3516 Cell culture/cell line expansion
Acetic acid, glacial Fisher BP2401 500 Making collagen coated plates
AlexaFluor 488 phalloidin Invitrogen A12379 Fluorescent f-actin counterstain
Belzer UW Cold Storage Transplant Solution Bridge to Life BUW0011L Tissue storage solution
Bovine Serum Albumin, Fraction V - Fatty Acid Free 25g Bioworld 220700233 VEC confirmation with CD31+ Dynabeads
Calponin 1 antibody  Abcam ab46794 Primary antibody (VIC positive stain)
CD31 (PECAM-1) (89C2) Cell Signaling 3528 Primary antibody (VEC positive stain)
CD31+ Dynabeads Invitrogen 11155D VEC confirmation with CD31+ Dynabeads
CDH5 Cell Signaling 2500 Primary antibody (VEC positive stain)
Cell strainer with 0.70 μm pores Corning 431751 VIC isolation
Collagen 1, rat tail protein Gibco A1048301 Making collagen coated plates
Collagenase II Worthington Biochemical Corporation LS004176 Tissue digestion. Tissue preparation, VIC/VEC isolation
Conflikt Ready-to-use Disinfectant Spray Decon 4101 Disinfection
Countess II Automated Cell Counter Invitrogen A27977 Automated cell counter
Countess II reusable slide coverslips Invitrogen 2026h Automated cell counter required slide cover
Coverslips Fisher 125485E Mounting valve samples
Cryogenic vials Olympus Plastics 24-202 Freezing cells/tissue samples
Disinfecting Bleach with CLOROMAX - Concentrated Formula  Clorox N/A Disinfection
DMEM Gibco 10569044 Growth media. VIC expansion
EBM - Endothelial Cell Medium, Basal Medium, Phenol Red free 500 Lonza Walkersville CC3129 Growth media. VEC expansion
EGM-2 Endothelial Cell Medium-2 - 1 kit SingleQuot Kit Lonza Walkersville CC4176 Growth media supplement. VEC expansion
EVOS FL Microscope Life Technologies Model Number: AME3300 Fluorescent imaging
EVOS XL Microscope Life Technologies AMEX1000 Visualizing cells during cell line expansion
Fetal Bovine Serum - Premium Select R&D Systems S11550 VIC expansion
Fine scissors Fine Science Tools 14088-10 Tissue preparation, VIC/VEC isolation
Fisherbrand Cell Scrapers Fisher 08-100-241 VIC expansion
Fungizone Gibco 15290-026 Antifungal: Tissue preparation, VIC/VEC isolation
Gentamicin Gibco 15710-064 Antibiotic: Tissue preparation, VIC/VEC isolation
Glass slides Globe Scientific Inc 1358L mounting valve samples
Goat anti-Mouse 488 Invitrogen A11001 Fluorescent secondary Antibody
Goat anti-Mouse 594 Invitrogen A11005 Fluorescent secondary Antibody
Goat anti-Rabbit 488 Invitrogen A11008 Fluorescent secondary Antibody
Goat anti-Rabbit 594 Invitrogen A11012 Fluorescent secondary Antibody
Invitrogen Countess II FL Reusable Slide Invitrogen A25750 Automated cell counter required slide
Invitrogen NucBlue Fixed Cell ReadyProbes Reagent (DAPI) Invitrogen R37606 Fluorescent nucleus counterstain
LM-HyCryo-STEM - 2X Cryopreservation media for stem cells HyClone Laboratories, Inc. SR30002 Frozen cell storage
Mounting Medium Fisher Chemical Permount SP15-100 Mounting valve samples
Mr. Frosty freezing container Nalgene 51000001 Container for controlled sample freezing
Mycoplasma-ExS Spray PromoCell PK-CC91-5051 Disinfection
Penicillin-Streptomycin Gibco 15140163 Antibiotic. VIC expansion
Plasmocin Invivogen ANTMPT Anti-mycoplasma. VIC/VEC isolation and expansion
SM22a antibody Abcam ab14106 Primary antibody (VIC positive stain)
Sstandard pattern scissors Fine Science Tools 14001-14 Tissue preparation, VIC/VEC isolation
Sterile cotton swab Puritan 25806 10WC VEC isolation
Swingsette human tissue cassette Simport Scientific M515-2 Tissue embedding container
Taylor Forceps (17cm) Fine Science Tools 11016-17 Tissue preparation, VIC/VEC isolation
Trypan Blue Solution, 0.4% Gibco 15250061 cell counting solution
TrypLE Express Enzyme Gibco 12604021 Splitting VIC/VECs
Von Kossa kit Polysciences 246331 Staining paraffin sections of tissues for calcification
von Willebrand factor antibody Abcam ab68545 Primary antibody (VEC positive stain)
Xylenes Fisher Chemical X3S-4 Deparaffinizing tissue samples
αSMA antibody Abcam ab7817 Primary antibody (VIC positive stain)

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