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Nakazawa Y, Koge J, Morishige N, Kato S, Kawajiri M, Yamada T. [A case of recurrent cerebral embolism associated with Lambl's excrescence]. Rinsho Shinkeigaku 2022; 62:145-151. [PMID: 35095051 DOI: 10.5692/clinicalneurol.cn-001671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A 75-year-old female had a history of prior ischemic stroke with aphasia and right hemiplegia. Magnetic resonance angiography showed left internal carotid artery occlusion. She was successfully treated with intravenous recombinant tissue plasminogen activator (IV t-PA) and underwent endovascular thrombectomy (EVT). She was diagnosed with cardioembolic stroke due to the presence of atrial fibrillation and mitral valve stenosis, and warfarin was administered. However, she experienced large vessel occlusion twice within 2 years. Upon further analysis, transesophageal echocardiography revealed a mobile hyperechoic structure on the aortic valve, which was assumed to be an embolic source. Thus, we decided to perform mitral and aortic valve replacement. The excised aortic valve structure was suggested to be an example of Lambl's excrescence, histopathologically. After surgery, the patient had no recurrence for 3 years. Several cases of ischemic stroke associated with Lambl's excrescence have been reported, but definitive guidelines for managing patients with Lambl's excrescence do not currently exist. Surgical intervention for Lambl's excrescence with recurrent ischemic events may be important for preventing further recurrence.
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Affiliation(s)
| | - Junpei Koge
- Division of Neurology, Saiseikai Fukuoka General Hospital
| | | | - Seiya Kato
- Division of Pathology, Saiseikai Fukuoka General Hospital
| | | | - Takeshi Yamada
- Division of Neurology, Saiseikai Fukuoka General Hospital
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2
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Nordquist EM, Dutta P, Kodigepalli KM, Mattern C, McDermott MR, Trask AJ, LaHaye S, Lindner V, Lincoln J. Tgfβ1-Cthrc1 Signaling Plays an Important Role in the Short-Term Reparative Response to Heart Valve Endothelial Injury. Arterioscler Thromb Vasc Biol 2021; 41:2923-2942. [PMID: 34645278 PMCID: PMC8612994 DOI: 10.1161/atvbaha.121.316450] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
OBJECTIVE Aortic valve disease is a common worldwide health burden with limited treatment options. Studies have shown that the valve endothelium is critical for structure-function relationships, and disease is associated with its dysfunction, damage, or injury. Therefore, therapeutic targets to maintain a healthy endothelium or repair damaged endothelial cells could hold promise. In this current study, we utilize a surgical mouse model of heart valve endothelial cell injury to study the short-term response at molecular and cellular levels. The goal is to determine if the native heart valve exhibits a reparative response to injury and identify the mechanisms underlying this process. Approach and Results: Mild aortic valve endothelial injury and abrogated function was evoked by inserting a guidewire down the carotid artery of young (3 months) and aging (16-18 months) wild-type mice. Short-term cellular responses were examined at 6 hours, 48 hours, and 4 weeks following injury, whereas molecular profiles were determined after 48 hours by RNA-sequencing. Within 48 hours following endothelial injury, young wild-type mice restore endothelial barrier function in association with increased cell proliferation, and upregulation of transforming growth factor beta 1 (Tgfβ1) and the glycoprotein, collagen triple helix repeat containing 1 (Cthrc1). Interestingly, this beneficial response to injury was not observed in aging mice with known underlying endothelial dysfunction. CONCLUSIONS Data from this study suggests that the healthy valve has the capacity to respond to mild endothelial injury, which in short term has beneficial effects on restoring endothelial barrier function through acute activation of the Tgfβ1-Cthrc1 signaling axis and cell proliferation.
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Affiliation(s)
- Emily M. Nordquist
- Molecular, Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH, USA
- Department of Pediatrics, Section of Pediatric Cardiology, Medical College of Wisconsin, Milwaukee, WI, USA
- The Herma Heart Institute, Children’s Wisconsin, Milwaukee, WI, USA
| | - Punashi Dutta
- Department of Pediatrics, Section of Pediatric Cardiology, Medical College of Wisconsin, Milwaukee, WI, USA
- The Herma Heart Institute, Children’s Wisconsin, Milwaukee, WI, USA
| | - Karthik M. Kodigepalli
- Department of Pediatrics, Section of Pediatric Cardiology, Medical College of Wisconsin, Milwaukee, WI, USA
- The Herma Heart Institute, Children’s Wisconsin, Milwaukee, WI, USA
| | - Carol Mattern
- Department of Pediatrics, Section of Pediatric Cardiology, Medical College of Wisconsin, Milwaukee, WI, USA
- The Herma Heart Institute, Children’s Wisconsin, Milwaukee, WI, USA
| | - Michael R. McDermott
- Center for Cardiovascular Research, The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, Ohio, USA
- The Heart Center, Nationwide Children’s Hospital, Columbus, Ohio, USA
| | - Aaron J. Trask
- Center for Cardiovascular Research, The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, Ohio, USA
- The Heart Center, Nationwide Children’s Hospital, Columbus, Ohio, USA
- Department of Pediatrics, The Ohio State University, Columbus, Ohio, USA
| | - Stephanie LaHaye
- The Institute for Genomic Medicine, The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, Ohio, USA
| | - Volkhard Lindner
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine, USA
| | - Joy Lincoln
- Department of Pediatrics, Section of Pediatric Cardiology, Medical College of Wisconsin, Milwaukee, WI, USA
- The Herma Heart Institute, Children’s Wisconsin, Milwaukee, WI, USA
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3
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Chignon A, Bon-Baret V, Boulanger MC, Bossé Y, Mathieu P. Oxyphospholipids in Cardiovascular Calcification. Arterioscler Thromb Vasc Biol 2020; 41:11-19. [PMID: 33232199 DOI: 10.1161/atvbaha.120.313790] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mineralization of cardiovascular structures including blood vessels and heart valves is a common feature. We postulate that ectopic mineralization is a response-to-injury in which signals delivered to cells trigger a chain of events to restore and repair tissues. Maladaptive response to external or internal signals promote the expression of danger-associated molecular patterns, which, in turn, promote, when expressed chronically, a procalcifying gene program. Growing evidence suggest that danger-associated molecular patterns such as oxyphospholipids and small lipid mediators, generated by enzyme activity, are involved in the transition of vascular smooth muscle cells and valve interstitial cells to an osteoblast-like phenotype. Understanding the regulation and the molecular processes underpinning the mineralization of atherosclerotic plaques and cardiac valves are providing valuable mechanistic insights, which could lead to the development of novel therapies. Herein, we provide a focus account on the role oxyphospholipids and their mediators in the development of mineralization in plaques and calcific aortic valve disease.
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Affiliation(s)
- Arnaud Chignon
- Department of Surgery, Laboratory of Cardiovascular Pathobiology, Quebec Heart and Lung Institute/Research Center (A.C., V.B.-B., M.-C.B., P.M.), Laval University, Canada
| | - Valentin Bon-Baret
- Department of Surgery, Laboratory of Cardiovascular Pathobiology, Quebec Heart and Lung Institute/Research Center (A.C., V.B.-B., M.-C.B., P.M.), Laval University, Canada
| | - Marie-Chloé Boulanger
- Department of Surgery, Laboratory of Cardiovascular Pathobiology, Quebec Heart and Lung Institute/Research Center (A.C., V.B.-B., M.-C.B., P.M.), Laval University, Canada
| | - Yohan Bossé
- Department of Molecular Medicine (Y.B.), Laval University, Canada
| | - Patrick Mathieu
- Department of Surgery, Laboratory of Cardiovascular Pathobiology, Quebec Heart and Lung Institute/Research Center (A.C., V.B.-B., M.-C.B., P.M.), Laval University, Canada
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Bertazzo S, Gentleman E. Aortic valve calcification: a bone of contention. Eur Heart J 2019; 38:1189-1193. [PMID: 26994153 PMCID: PMC5400053 DOI: 10.1093/eurheartj/ehw071] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 02/01/2016] [Indexed: 12/15/2022] Open
Affiliation(s)
- Sergio Bertazzo
- Department of Medical Physics & Biomedical Engineering, University College London, Malet Place Engineering Building, London WC1E 6BT, UK
| | - Eileen Gentleman
- Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK
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5
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Prevention of aortic valve stenosis: A realistic therapeutic target? Pharmacol Ther 2012; 135:78-93. [DOI: 10.1016/j.pharmthera.2012.04.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 03/16/2012] [Indexed: 11/21/2022]
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Ngo DT, Stafford I, Sverdlov AL, Qi W, Wuttke RD, Zhang Y, Kelly DJ, Weedon H, Smith MD, Kennedy JA, Horowitz JD. Ramipril retards development of aortic valve stenosis in a rabbit model: mechanistic considerations. Br J Pharmacol 2011; 162:722-32. [PMID: 20958293 DOI: 10.1111/j.1476-5381.2010.01084.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE Aortic valve stenosis (AVS) is associated with significant cardiovascular morbidity and mortality. To date, no therapeutic modality has been shown to be effective in retarding AVS progression. We evaluated the effect of angiotensin-converting enzyme inhibition with ramipril on disease progression in a recently developed rabbit model of AVS. EXPERIMENTAL APPROACH The effects of 8 weeks of treatment with either vitamin D₂ at 25,000 IU for 4 days a week alone or in combination with ramipril (0.5 mg·kg⁻¹) on aortic valve structure and function were examined in New Zealand white rabbits. Echocardiographic aortic valve backscatter (AV(BS)) and aortic valve:outflow tract flow velocity ratio were utilized to quantify changes in valve structure and function. KEY RESULTS Treatment with ramipril significantly reduced AV(BS) and improved aortic valve :outflow tract flow velocity ratio. The intravalvular content of the pro-oxidant thioredoxin-interacting protein was decreased significantly with ramipril treatment. Endothelial function, as measured by asymmetric dimethylarginine concentrations and vascular responses to ACh, was improved significantly with ramipril treatment. CONCLUSIONS AND IMPLICATIONS Ramipril retards the development of AVS, reduces valvular thioredoxin-interacting protein accumulation and limits endothelial dysfunction in this animal model. These findings provide important insights into the mechanisms of AVS development and an impetus for future human studies of AVS retardation using an angiotensin-converting enzyme inhibitor.
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Affiliation(s)
- Doan Tm Ngo
- Department of Medicine, Vascular Disease and Therapeutics Research Group, Basil Hetzel Institute, The Queen Elizabeth Hospital, The University of Adelaide, South Australia, Australia
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Butcher JT, Mahler GJ, Hockaday LA. Aortic valve disease and treatment: the need for naturally engineered solutions. Adv Drug Deliv Rev 2011; 63:242-68. [PMID: 21281685 DOI: 10.1016/j.addr.2011.01.008] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 01/05/2011] [Accepted: 01/14/2011] [Indexed: 01/21/2023]
Abstract
The aortic valve regulates unidirectional flow of oxygenated blood to the myocardium and arterial system. The natural anatomical geometry and microstructural complexity ensures biomechanically and hemodynamically efficient function. The compliant cusps are populated with unique cell phenotypes that continually remodel tissue for long-term durability within an extremely demanding mechanical environment. Alteration from normal valve homeostasis arises from genetic and microenvironmental (mechanical) sources, which lead to congenital and/or premature structural degeneration. Aortic valve stenosis pathobiology shares some features of atherosclerosis, but its final calcification endpoint is distinct. Despite its broad and significant clinical significance, very little is known about the mechanisms of normal valve mechanobiology and mechanisms of disease. This is reflected in the paucity of predictive diagnostic tools, early stage interventional strategies, and stagnation in regenerative medicine innovation. Tissue engineering has unique potential for aortic valve disease therapy, but overcoming current design pitfalls will require even more multidisciplinary effort. This review summarizes the latest advancements in aortic valve research and highlights important future directions.
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Atherosclerotic-like process in aortic stenosis: Activation of the tissue factor–thrombin pathway and potential role through osteopontin alteration. Atherosclerosis 2010; 213:369-76. [DOI: 10.1016/j.atherosclerosis.2010.07.047] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 07/15/2010] [Accepted: 07/22/2010] [Indexed: 11/20/2022]
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9
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Marechaux S, Corseaux D, Vincentelli A, Richardson M, Ung A, Susen S, Zawadzki C, Beregi JP, Ezekowitz MD, Jude B, Le Tourneau T. Identification of tissue factor in experimental aortic valve sclerosis. Cardiovasc Pathol 2009; 18:67-76. [DOI: 10.1016/j.carpath.2007.12.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Revised: 09/12/2007] [Accepted: 12/27/2007] [Indexed: 11/28/2022] Open
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10
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Chorianopoulos E, Bea F, Katus HA, Frey N. The role of endothelial cell biology in endocarditis. Cell Tissue Res 2008; 335:153-63. [PMID: 19015889 DOI: 10.1007/s00441-008-0687-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Accepted: 08/25/2008] [Indexed: 11/26/2022]
Abstract
The treatment of endocarditis remains a challenge for physicians, even in times of modern antibiotic treatment. Depending on its cause, endocarditis can either be of infectious or non-infectious origin. Infective endocarditis is caused by bacterial (or fungal) pathogens, and the clinical course is critically dependent on the virulence factors of the specific microorganisms involved. Therefore, the clinical type of endocarditis can be divided into an acute and more aggressive form and a subacute form (endocarditis lenta). Much of our knowledge regarding the pathogenesis of infective endocarditis is based on studies of the virulence of Staphylococcus aureus, which has become the most frequent cause of infective endocarditis nowadays. However, independently of the underlying cause of endocarditis (infectious or noninfectious), the pathogenesis involves the damage and disturbance of endothelial function and the formation of associated "vegetation". Surprisingly little is known about the specific role of the endothelium in the pathogenesis of endocarditis. This review will thus give insights into current knowledge of the pathogenesis of endocarditis with a focus on the role of the endothelium.
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Affiliation(s)
- E Chorianopoulos
- Department of Cardiology, Angiology and Pulmology, Internal Medicine III, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
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11
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Chalajour F, Treede H, Gehling UM, Ebrahimnejad A, Boehm DH, Riemer RK, Ergun S, Reichenspurner H. Identification and characterization of cells with high angiogenic potential and transitional phenotype in calcific aortic valve. Exp Cell Res 2007; 313:2326-35. [PMID: 17475245 DOI: 10.1016/j.yexcr.2007.02.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Revised: 01/03/2007] [Accepted: 02/28/2007] [Indexed: 11/27/2022]
Abstract
Recent data suggest that angiogenesis plays an important role in the pathogenesis of valvular disease. However, the cellular mechanisms underlying this process remain unknown. This study aimed at identifying and characterizing the cellular components responsible for pathological neovascularization in calcific aortic valves (CAV). Immunohistochemical analysis of uncultured CAV tissues revealed that smooth muscle alpha-actin (alpha-SMA)-positive cells, which coexpressed Tie-2 and vascular endothelial growth factor receptor-2 (VEGFR-2), can be identified prior to the initiation of capillary-like tube formation. In a second step, leaflets of CAV and non-calcific aortic valves (NCAV) were cultured and the cells involved in capillary-like tube formation were isolated. The majority of these cells displayed the same phenotype as non-cultured cells identified in CAV tissues, i.e., expression of alpha-SMA, Tie-2, and VEGFR-2. In comparison to cells isolated from cultures of NCAV leaflets, these cells showed enhanced angiogenic activity as demonstrated by migration and tube assays. The coexpression of VEGFR-2 and Tie-2 together with alpha-SMA suggests both endothelial and mesenchymal properties of the angiogenically activated cells involved in valvular neovascularization. Hence, our findings might provide new insights into the process of pathological angiogenesis in cardiac valves.
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Affiliation(s)
- Fariba Chalajour
- Department of Cardiovascular Surgery, University Heart Center-Hamburg, Martinistr 52, Hamburg, Germany.
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12
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Chalajour F, Treede H, Ebrahimnejad A, Lauke H, Reichenspurner H, Ergun S. Angiogenic activation of valvular endothelial cells in aortic valve stenosis. Exp Cell Res 2004; 298:455-64. [PMID: 15265693 DOI: 10.1016/j.yexcr.2004.04.034] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2004] [Revised: 04/16/2004] [Indexed: 11/30/2022]
Abstract
Here, we demonstrate the angiogenic response of valvular endothelial cells to aortic valve (AV) stenosis using a new ex vivo model of aortic leaflets. Histological analysis revealed neovascularization within the cusps of stenotic but not of non-stenotic aortic valves. Correspondingly, the number of capillary-like outgrowth in 3D collagen gel was significantly higher in stenotic than in non-stenotic valves. Capillary-like sprouting was developed significantly faster in stenotic than in non-stenotic valves. New capillary sprouts from stenotic aortic valves exhibited the endothelial cell markers CD31, CD34 and von-Willebrand factor (vWF) as well as carcinoembryonic antigen cell adhesion molecule-1 (CEACAM1), Tie-2 and angiogenesis inhibitor endostatin. Western blot analyses revealed a significant increase of CEACAM1 and endostatin in stenotic aortic valve tissue. Electron microscopic examinations demonstrate that these capillary-like tubes are formed by endothelial cells containing Weibel-Palade bodies. Remarkably, inter-endothelial junctions are established and basement membrane material is partially deposited on the basal side of the endothelial tubes. Our data demonstrate the capillary-like sprout formation from aortic valves and suggest a role of angiogenesis in the pathogenesis of aortic valve stenosis. These data provide new insights into the mechanisms of valvular disorders and open new perspectives for prevention and early treatment of calcified aortic stenosis.
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MESH Headings
- Aged
- Antigens, CD/metabolism
- Antigens, CD34/metabolism
- Antigens, Differentiation/metabolism
- Aortic Valve/growth & development
- Aortic Valve/pathology
- Aortic Valve/physiopathology
- Aortic Valve Stenosis/metabolism
- Aortic Valve Stenosis/pathology
- Aortic Valve Stenosis/physiopathology
- Basement Membrane/metabolism
- Basement Membrane/ultrastructure
- Capillaries/metabolism
- Capillaries/pathology
- Capillaries/physiopathology
- Cell Adhesion Molecules
- Endostatins/metabolism
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/ultrastructure
- Female
- Humans
- Intercellular Junctions/metabolism
- Intercellular Junctions/ultrastructure
- Male
- Microscopy, Electron
- Models, Biological
- Neovascularization, Pathologic/metabolism
- Neovascularization, Pathologic/pathology
- Neovascularization, Pathologic/physiopathology
- Organ Culture Techniques
- Platelet Endothelial Cell Adhesion Molecule-1/metabolism
- Receptor, TIE-2/metabolism
- Weibel-Palade Bodies/metabolism
- Weibel-Palade Bodies/ultrastructure
- von Willebrand Factor/metabolism
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Affiliation(s)
- Fariba Chalajour
- Department of Cardiovascular Surgery, University Hospital Eppendorf, Hamburg, Germany
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13
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Abstract
It has become increasingly evident that the endothelium plays a critical role in the pathogenesis of valvular heart disease. The endothelium helps regulate vascular tone, inflammation, thrombosis, and vascular remodeling. Dysfunction of the endothelial cells has been linked to many vascular disorders including atherosclerosis. Common valvular diseases such as senile degenerative valve disease, myxomatous (or floppy) valves, rheumatic valves, and infective endocarditis valves show changes in the synthetic, morphologic, and metabolic functions of the valvular endothelial cells. These diseases are active processes related to endothelial cell dysfunction. Endothelial cell dysfunction is caused by mechanical forces, bacterial infection, autoantibodies, and circulating modulators of endothelial cell function. This study reviews the role of endothelial cell dysfunction in the more common valvular diseases. Continued research on endothelial cell dysfunction is crucial to our understanding of valvular heart diseases and may elucidate novel treatment and prevention strategies.
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Affiliation(s)
- Richard L Leask
- Department of Pathology, University Health Network, Toronto General Hospital, Toronto, Ontario, Canada
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Abstract
We have studied four cases of acute rheumatic carditis at autopsy in which the cardiac valves revealed rheumatic vegetations. The features of these vegetations were investigated by scanning electron microscopy. There was a loss of the normal mosaic arrangement of endothelial cells and marked architectural modifications of the valvar collagen. These features explain well the pathologic processes of rheumatic valvitis and the infective complications, if any, thereof. To the best of our knowledge, this is the first time that an analysis has been made of the structure of the surface of rheumatic vegetations.
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Affiliation(s)
- P Chopra
- Department of Pathology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi
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15
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Riddle JM, Wang CH, Magilligan DJ, Stein PD. Scanning electron microscopy of surgically excised human mitral valves in patients over 45 years of age. Am J Cardiol 1989; 63:471-7. [PMID: 2916433 DOI: 10.1016/0002-9149(89)90322-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Leaflets were obtained from 23 diseased mitral valves of patients over 45 years of age removed at the time of prosthetic valve insertion and the topography was studied with scanning electron microscopy. The clinical diagnosis in all cases was probable rheumatic heart disease. Filiform processes (Lambl's excrescences) were seen on 15 of 23 (65%) of these leaflets. Some of these processes appeared to develop when either bundles of collagen or elastic fibers in the connective tissue framework of the cusp were broken. The freed portion of the fiber then served as a nidus for thrombus formation. The endothelium on the surface of the leaflets was consistently altered. Endothelial cells were changed in shape, had microvilli scattered over their exterior, showed discontinuous cell borders and were desquamated, either singly or in groups. Elements of the peripheral blood adhered to the exposed subendothelium. Erythrocytes were usually entrapped in fibrin networks. Single activated platelets and platelet aggregates adhered to the fibers of the exposed subendothelial connective tissue. Surface mineral deposits were composed of granular spherulites, which contained both calcium and phosphorous. This study extends our understanding of the architectural modifications that contribute to the continuing pathologic process of rheumatic mitral valve disease.
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Affiliation(s)
- J M Riddle
- Henry Ford Heart and Vascular Institute, Detroit, Michigan 48202
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16
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Hurle JM, Garcia-Martinez V, Sanchez-Quintana D. Morphologic characteristics and structure of surface excrescences (Lambl's excrescences) in the normal aortic valve. Am J Cardiol 1986; 58:1223-7. [PMID: 3788812 DOI: 10.1016/0002-9149(86)90386-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The incidence, morphologic characteristics and structure of surface valve excrescences (Lambl's excrescences) were studied by transmission and scanning electron microscopy of the aortic valve of 56 human subjects, age range birth to 91 years, without cardiac disease. Valve excrescences consisting of a core of connective tissue covered by the endocardium were observed in 90% of the subjects; the incidence was significantly lower in patients in the first decade of life. Two types of excrescences, lamellar and filiform, were found. Lamellar excrescences are located along the lower boundary of the lunulas and occurred more often in those younger than 30 years. Filiform excrescences appear most often in the nodulus Arantius and in the free-margin of the cusps. The excrescences of the nodulus are the most numerous. Free-margin excrescences are the least numerous and occur more frequently in persons older than 40 years. The connective tissue core of the filiform excrescences contains abundant collagen fibrils and elastic material arranged in apposed layers with different collagen fibril orientation. A circular zone devoid of identifiable connective tissue is present at the center of the filiform excrescences.
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17
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Mackay A, de Bono DP. Valvar aortic stenosis in adults: an update. Scott Med J 1986; 31:20-4. [PMID: 3961467 DOI: 10.1177/003693308603100105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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18
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Hurle JM, Colvee E, Fernandez-Teran MA. The surface anatomy of the human aortic valve as revealed by scanning electron microscopy. ANATOMY AND EMBRYOLOGY 1985; 172:61-7. [PMID: 4037373 DOI: 10.1007/bf00318944] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The anatomy of the human aortic valve was studied by SEM in 36 subjects without cardiac pathology who had died of various accidental causes. Villous and lamellar tissue excrescences were observed at the node of Arantius and at the limit between the lunules and the load-bearing portion of the leaflets. The morphology of these structures suggests that they represent areas in which valve tissue becomes detached into the bloodstream. Fenestrations were present in the lunules of 14 specimens, with a higher incidence in specimens from subjects who were middle-aged or older. Our observations suggest that fenestrations appear initially as small perforations which then coalesce to form larger apertures. Two main types of endothelial cells, elongated and polygonal were detected on the endothelial surface of the leaflets. Both types of cells display a constant mode of arrangement on the different segments of the leaflets (lunules, node of Arantius and load-bearing portion of the leaflet). The possible relationships between endothelial cell morphology and the pattern of mechanical stress to which the leaflets are subjected is discussed.
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Riddle JM, Stein PD, Magilligan DJ, McElroy HH. Evaluation of platelet reactivity in patients with valvular heart disease. J Am Coll Cardiol 1983; 1:1381-4. [PMID: 6853895 DOI: 10.1016/s0735-1097(83)80039-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Transmission electron microscopy with a standardized in vitro method was used to evaluate the degree of blood platelet reactivity in 72 normal subjects and 72 patients with valvular heart disease. Among the patients with abnormal natural heart valves, 51 had either aortic insufficiency or aortic stenosis, and 21 patients showed either mitral insufficiency or mitral stenosis. For normal subjects, the platelet differential counts were dominated by the dendritic type platelet, and only a few platelets showed cytoplasmic spreading between adjacent pseudopodia (spread type). A hyperactive response was defined as greater than 20% of the spread type platelet or more than 93 aggregates per 100 single platelets counted, or both. Only 6 (8%) of the 72 normal subjects showed hyperactive platelets. In contrast, 45 (62%) of the 72 patients with valvular heart disease had hyperactive platelets (p less than 0.01). For patients with abnormal valves, the mean percent of the spread type platelet was 35% with a mean value of 105 platelet aggregates. The increased level of platelet reactivity was independent of both the position of the valve (aortic versus mitral) and its functional status (insufficient versus stenotic). Disturbed flow and the exposure of subendothelial thrombus-producing materials are features associated with abnormal heart valves. These factors, which usually occur in combination, may explain the hyperactive platelet response found in these patients.
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Hurle JM, Colvee E. Changes in the endothelial morphology of the developing semilunar heart valves. A TEM and SEM study in the chick. ANATOMY AND EMBRYOLOGY 1983; 167:67-83. [PMID: 6881544 DOI: 10.1007/bf00304601] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In view of recent evidence showing that shape and orientation of endothelial cells is determined by blood flow, the endothelium of the semilunar valves was studied in the developing chick heart using transmission and scanning electron microscopy. The results reveal significant developmental modifications of endothelial morphology and structure. These modifications can be linked to modifications of local blood flow and can also explain several aspects of valvular morphogenesis. The results substantially support the hypothesis of an involvement of hemodynamics in the development of the semilunar valves.
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