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Van Hecke M, Langenaeken T, Rega F, Roskams T, Meuris B. Validation of large animal models in mechanical valve research: a histologic comparison. Interdiscip Cardiovasc Thorac Surg 2024:ivae070. [PMID: 38637938 DOI: 10.1093/icvts/ivae070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Revised: 03/15/2024] [Accepted: 04/17/2024] [Indexed: 04/20/2024]
Abstract
OBJECTIVES Mechanical valves still require life-long anticoagulation. Preclinical animal testing is a crucial step in the assessment of valves, however the chosen animal model should be carefully considered, and a well-controlled animal model of mechanical valve thrombosis has not been established yet. In this study, a histopathologic comparison was performed to evaluate the representativity of pigs and sheep as large animal models in bileaflet mechanical valve thrombosis research. METHODS 10 pigs and 8 sheep were implanted with a bileaflet mechanical valve in pulmonary position. During follow-up, no anticoagulative therapy was administered. Pigs were sacrificed between 14-38 days for explantation and assessment of the valve. Sheep were sacrificed between 71-155 days. Thrombus samples were processed and (immuno)histochemical stainings were applied. A pathologist evaluated the samples morphologically and semiquantitatively and compared these samples to available slides from 3 human patients who underwent redo surgery for acute bileaflet mechanical valve thrombosis, caused by insufficient anticoagulation. RESULTS All pigs showed macroscopically evident thrombi on the mechanical valve surface at sacrifice. In contrast, none of the sheep showed any sign of thrombus formation. Histology showed a high fibrin content in thrombi of both human and porcine cases (3/3 vs 8/10). Porcine thrombi showed more cellular organization (0/3 vs 6/10), more calcification (0/3 vs 9/10) and more endothelialisation (0/3 vs 6/10). Inflammatory cells were present in all samples and were considered physiological. CONCLUSIONS Contrary to sheep, pigs develop thrombi on their mechanical valves in the short-term if no anticoagulation is administered. Histologic comparison of human and porcine thrombi shows comparable findings. The pig model might serve interestingly for further research on valve thrombosis, if it shows not to be an overly aggressive model.
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Affiliation(s)
- Manon Van Hecke
- Department of Pathology, University Hospitals Leuven, Leuven, Belgium
| | - Tom Langenaeken
- Department of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium
| | - Filip Rega
- Department of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium
| | - Tania Roskams
- Department of Pathology, University Hospitals Leuven, Leuven, Belgium
| | - Bart Meuris
- Department of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium
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Minten L, Langenaeken T, McCutcheon K, Bennett J, Van Hecke M, Algoet M, Bézy S, Duchenne J, Puvrez A, Wouters L, Voigt JU, Adriaenssens T, Desmet W, Sinnaeve P, Verbrugghe P, Oosterlinck W, Claus P, Meuris B, Dubois C. An interventional sheep model of severe aortic valve stenosis hemodynamics for the evaluation of alterations in coronary physiology and microvascular function. J Appl Physiol (1985) 2024; 136:606-617. [PMID: 38328825 DOI: 10.1152/japplphysiol.00737.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 02/02/2024] [Indexed: 02/09/2024] Open
Abstract
We aimed to develop a large animal model of subcoronary aortic stenosis (AS) to study intracoronary and microcirculatory hemodynamics. A total of three surgical techniques inducing AS were evaluated in 12 sheep. Suturing the leaflets together around a dilator (n = 2) did not result in severe AS. Suturing of a pericardial patch with a variable opening just below the aortic valve (n = 5) created an AS which was poorly tolerated if the aortic valve area (AVA) was too small (0.38-1.02 cm2), but was feasible with an AVA of 1.2 cm2. However, standardization of aortic regurgitation (AR) with this technique is difficult. Therefore, we opted for implantation of an undersized AV-bioprosthesis with narrowing sutures on the leaflets (n = 5). Overall, five sheep survived the immediate postoperative period of which three had severe AS (one patch and two bioprostheses). The surviving sheep with severe AS developed left ventricular hypertrophy and signs of increased filling-pressures. Intracoronary assessment of physiological indices in these AS sheep pointed toward the development of functional microvascular dysfunction, with a significant increase in coronary resting flow and hyperemic coronary resistance, resulting in a significantly higher index of microvascular resistance (IMR) and lower myocardial resistance reserve (MRR). Microscopic analysis showed myocardial hypertrophy and signs of fibrosis without evidence of capillary rarefaction. In a large animal model of AS, microvascular changes are characterized by increased resting coronary flow and hyperemic coronary resistance resulting in increased IMR and decreased MRR. These physiological changes can influence the interpretation of regularly used coronary indices.NEW & NOTEWORTHY In an animal model of aortic valve stenosis (AS), coronary physiological changes are characterized by increased resting coronary flow and hyperemic coronary resistance. These changes can impact coronary indices frequently used to assess concomitant coronary artery disease (CAD). At this point, the best way to assess and treat CAD in AS remains unclear. Our data suggest that fractional flow reserve may underestimate CAD, and nonhyperemic pressure ratios may overestimate CAD severity before aortic valve replacement.
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Affiliation(s)
- Lennert Minten
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
- Department of Cardiovascular Medicine, University Hospitals Leuven (UZ Leuven), Leuven, Belgium
| | - Tom Langenaeken
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
- Department of Cardiac Surgery, University Hospitals Leuven (UZ Leuven), Leuven, Belgium
| | - Keir McCutcheon
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | - Johan Bennett
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
- Department of Cardiovascular Medicine, University Hospitals Leuven (UZ Leuven), Leuven, Belgium
| | - Manon Van Hecke
- Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Michiel Algoet
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
- Department of Cardiac Surgery, University Hospitals Leuven (UZ Leuven), Leuven, Belgium
| | - Stéphanie Bézy
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | - Jürgen Duchenne
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | - Alexis Puvrez
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | - Laurine Wouters
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | - Jens-Uwe Voigt
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
- Department of Cardiovascular Medicine, University Hospitals Leuven (UZ Leuven), Leuven, Belgium
| | - Tom Adriaenssens
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
- Department of Cardiovascular Medicine, University Hospitals Leuven (UZ Leuven), Leuven, Belgium
| | - Walter Desmet
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
- Department of Cardiovascular Medicine, University Hospitals Leuven (UZ Leuven), Leuven, Belgium
| | - Peter Sinnaeve
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
- Department of Cardiovascular Medicine, University Hospitals Leuven (UZ Leuven), Leuven, Belgium
| | - Peter Verbrugghe
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
- Department of Cardiac Surgery, University Hospitals Leuven (UZ Leuven), Leuven, Belgium
| | - Wouter Oosterlinck
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
- Department of Cardiac Surgery, University Hospitals Leuven (UZ Leuven), Leuven, Belgium
| | - Piet Claus
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | - Bart Meuris
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
- Department of Cardiac Surgery, University Hospitals Leuven (UZ Leuven), Leuven, Belgium
| | - Christophe Dubois
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
- Department of Cardiovascular Medicine, University Hospitals Leuven (UZ Leuven), Leuven, Belgium
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Langenaeken T, De Meester P, Verbrugghe P, Rega F, Lamberigts M, Van Hecke M, Van Hoof L, Meuris B. In vivo performance of a tri-leaflet mechanical heart valve prosthesis in an ovine model. Interdiscip Cardiovasc Thorac Surg 2023; 37:ivad142. [PMID: 37584674 PMCID: PMC10457726 DOI: 10.1093/icvts/ivad142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 07/13/2023] [Accepted: 08/15/2023] [Indexed: 08/17/2023]
Abstract
OBJECTIVES We present the long-term results of a trileaflet (Triflo) versus bileaflet (On-X) mechanical valve in both aortic and pulmonary positions in a sheep model. METHODS The Triflo valve was implanted in 21 female sheep in aortic (n = 8) and pulmonary position (n = 13). The On-X valve was implanted in 7 female sheep in aortic (n = 1) and pulmonary (n = 6) positions. No antithrombotic medication of any kind was given postoperatively. In the aortic group, survival cohorts were 3 and 5 months. In the pulmonary group, survival cohorts were 10 and 20 weeks. Valve performance was assessed using haematology, echocardiography and acoustic measurements combined with post-mortem pathology analysis of the downstream organs. RESULTS The mean gradients were lower for the Triflo valve in both pulmonary [4.30 mmHg (3.70-5.73) vs 6.80 mmHg (4.63-7.96), P = 0.012] and aortic [5.1 mmHg (4.2-7.7) vs 10.7 mmHg (8.7-12.9), P = 0.007] positions. Peak gradients were lower for the Triflo valve in both pulmonary [8.05 mmHg (6.75-10.23) vs 13.15 mmHg (9.20-14.76), P = 0.005] and aortic [8.7 mmHg (7.5-12.5) vs 16.5 mmHg (14.2-19.6), P = 0.009] positions. In both positions, leaflets and housing surface were free from any deposits macro- and microscopically and comparable to nonimplanted control valves. Peripheral organs showed no signs of thrombo-embolic damage. Biochemical and haematological were comparable to preoperative. The closing click sound pressure level of the Triflo was significantly lower in both aortic [108.4 sound pressure level (102.0-115.7) vs 111.7 sound pressure level (105.5-117.0), P < 0.001] and pulmonary [103.6 sound pressure level (99.1-108.9) vs 118.5 sound pressure level (116.7-120.2), P < 0.001] position. CONCLUSIONS Preliminary in vivo results of the Triflo valve are promising in both aortic and pulmonary positions in an ovine model. Excellent haemodynamics, stable long-term function, low valve noise and no thrombo-embolic events in the absence of antithrombotic medication lay the foundation to a future clinical first-in-man trial.
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Affiliation(s)
- Tom Langenaeken
- Department of Cardiovascular Diseases, Research Unit of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium
| | - Pieter De Meester
- Congenital and Structural Cardiology, University Hospitals Leuven, Leuven, Belgium
| | - Peter Verbrugghe
- Department of Cardiovascular Diseases, Research Unit of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium
| | - Filip Rega
- Department of Cardiovascular Diseases, Research Unit of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium
| | - Marie Lamberigts
- Department of Cardiovascular Diseases, Research Unit of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium
| | - Manon Van Hecke
- Department of Pathology, University Hospitals Leuven, Leuven, Belgium
| | - Lucas Van Hoof
- Department of Cardiovascular Diseases, Research Unit of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium
| | - Bart Meuris
- Department of Cardiovascular Diseases, Research Unit of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium
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Van Hecke M, Van Hoof L, Sikole M, Mufty H, Claus P, Verbrugghe P, Ely J, Berg GA, Roskams T, Meuris B. A Large-Diameter Vascular Graft Replacing Animal-Derived Sealants With an Elastomeric Polymer. J Surg Res 2023; 284:6-16. [PMID: 36527768 DOI: 10.1016/j.jss.2022.11.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 10/25/2022] [Accepted: 11/20/2022] [Indexed: 12/16/2022]
Abstract
INTRODUCTION To assess the safety and efficacy of an experimental large-diameter vascular graft externally sealed with an elastomeric polymer when used as an interposition graft in the descending aorta of sheep. METHODS The experimental vascular grafts as well as control gelatin sealed interposition grafts were inserted into the descending aorta of juvenile sheep. The grafts were assessed by time to hemostasis and blood loss during surgery and hematology and biochemistry panels at distinct time points. Magnetic resonance imaging (MRI) was performed at 3 and at 6 mo after surgery, after which the animals were euthanized and necropsies were carried out including macroscopic and microscopic examination of the grafts, anastomoses, and distal organs. RESULTS All animals survived the study period. There was no perceivable difference in the surgical handling of the grafts. The median intraoperative blood loss was 27.5 mL (range 10.0-125.0 mL) in the experimental group and 50.0 mL (range 10.0-75.0 mL) in the control group. The median time to hemostasis was 5.0 min (range 2.0-16.0 min) minutes in the experimental group versus 6.0 min (range 4.0-6.0 min) in the control group. MRI showed normal flow and graft patency in both groups. Healing and perianastomotic endothelialization was similar in both groups. CONCLUSIONS The experimental graft has a similar safety and performance profile and largely comparable necropsy results, in comparison to a commonly used prosthetic vascular graft, with the experimental grafts eliciting a nonadherent external fibrous capsule as the major difference compared to the control grafts that were incorporated into the periadventitia. Survival, hemostatic sealing, and hematologic and radiologic results were comparable between the study groups.
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Affiliation(s)
- Manon Van Hecke
- Department of Pathology, University Hospitals Leuven, Leuven, Belgium.
| | - Lucas Van Hoof
- Department of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium
| | - Magdalena Sikole
- Department of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium
| | - Hozan Mufty
- Department of Vascular Surgery, University Hospitals Leuven, Leuven, Belgium
| | - Piet Claus
- KU Leuven, Department of Cardiovascular Sciences, Cardiovascular Imaging and Dynamics, Leuven, Belgium
| | - Peter Verbrugghe
- Department of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium
| | - John Ely
- RUA Life Sciences, Irvine, United Kingdom
| | | | - Tania Roskams
- Department of Pathology, University Hospitals Leuven, Leuven, Belgium
| | - Bart Meuris
- Department of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium
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Eens S, Van Hecke M, Favere K, Tousseyn T, Guns PJ, Roskams T, Heidbuchel H. B-cell lymphoblastic lymphoma following intravenous BNT162b2 mRNA booster in a BALB/c mouse: A case report. Front Oncol 2023; 13:1158124. [PMID: 37197431 PMCID: PMC10183601 DOI: 10.3389/fonc.2023.1158124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 04/13/2023] [Indexed: 05/19/2023] Open
Abstract
Unprecedented immunization campaigns have been rolled out worldwide in an attempt to contain the ongoing COVID-19 pandemic. Multiple vaccines were brought to the market, among two utilizing novel messenger ribonucleic acid technology. Despite their undisputed success in decreasing COVID-19-associated hospitalizations and mortality, various adverse events have been reported. The emergence of malignant lymphoma is one of such rare adverse events that has raised concern, although an understanding of the mechanisms potentially involved remains lacking. Herein, we present the first case of B-cell lymphoblastic lymphoma following intravenous high-dose mRNA COVID-19 vaccination (BNT162b2) in a BALB/c mouse. Two days following booster vaccination (i.e., 16 days after prime), at only 14 weeks of age, our animal suffered spontaneous death with marked organomegaly and diffuse malignant infiltration of multiple extranodal organs (heart, lung, liver, kidney, spleen) by lymphoid neoplasm. Immunohistochemical examination revealed organ sections positive for CD19, terminal deoxynucleotidyl transferase, and c-MYC, compatible with a B-cell lymphoblastic lymphoma immunophenotype. Our murine case adds to previous clinical reports on malignant lymphoma development following novel mRNA COVID-19 vaccination, although a demonstration of direct causality remains difficult. Extra vigilance is required, with conscientious reporting of similar cases and a further investigation of the mechanisms of action explaining the aforementioned association.
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Affiliation(s)
- Sander Eens
- Laboratory of Physiopharmacology, Genetics, Pharmacology and Physiopathology of Heart, Blood Vessels and Skeleton (GENCOR), University of Antwerp, Antwerp, Belgium
- Research Group Cardiovascular Diseases, Genetics, Pharmacology and Physiopathology of Heart, Blood Vessels and Skeleton (GENCOR), University of Antwerp, Antwerp, Belgium
- *Correspondence: Sander Eens,
| | - Manon Van Hecke
- Laboratory of Translational Cell and Tissue Research, Department of Imaging and Pathology, University of Leuven, Leuven, Belgium
| | - Kasper Favere
- Laboratory of Physiopharmacology, Genetics, Pharmacology and Physiopathology of Heart, Blood Vessels and Skeleton (GENCOR), University of Antwerp, Antwerp, Belgium
- Research Group Cardiovascular Diseases, Genetics, Pharmacology and Physiopathology of Heart, Blood Vessels and Skeleton (GENCOR), University of Antwerp, Antwerp, Belgium
- Department of Cardiology, Antwerp University Hospital, Antwerp, Belgium
- Department of Internal Medicine, Ghent University, Ghent, Belgium
| | - Thomas Tousseyn
- Laboratory of Translational Cell and Tissue Research, Department of Imaging and Pathology, University of Leuven, Leuven, Belgium
| | - Pieter-Jan Guns
- Laboratory of Physiopharmacology, Genetics, Pharmacology and Physiopathology of Heart, Blood Vessels and Skeleton (GENCOR), University of Antwerp, Antwerp, Belgium
| | - Tania Roskams
- Laboratory of Translational Cell and Tissue Research, Department of Imaging and Pathology, University of Leuven, Leuven, Belgium
| | - Hein Heidbuchel
- Research Group Cardiovascular Diseases, Genetics, Pharmacology and Physiopathology of Heart, Blood Vessels and Skeleton (GENCOR), University of Antwerp, Antwerp, Belgium
- Department of Cardiology, Antwerp University Hospital, Antwerp, Belgium
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