Publications by authors named "Allard C van der Wal"

151 Publications

Tissues attached to retrieved leadless pacemakers: Histopathological evaluation of tissue composition in relation to implantation time and complications.

Heart Rhythm 2021 Aug 28. Epub 2021 Aug 28.

Department of Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.

Background: Leadless pacemakers (LPs) have proven safe and effective, but device revisions remain necessary. Either replacing the LP or implanting a new adjacent LP is feasible. Replacement seems more appealing, but encapsulation and tissue adhesions may hamper the safety and efficacy of LP retrieval.

Objective: We determined the incidence and cellular characteristics of tissue adherent to retrieved LPs and the potential implications for end-of-life strategy.

Methods: All 15 consecutive successful Nanostim LP retrievals in a tertiary center were included. We assessed the histopathology of adherent tissue and obtained clinical characteristics.

Results: Adherent tissue was present in 14 of 15 retrievals (93%; median implantation duration 36 months; range 0-96 months). The tissue consisted of fibrosis (n = 2), fibrosis and thrombus (n = 9), or thrombus only (n = 3). In short-term retrievals (<1 year), mostly fresh thrombi without fibrosis were seen. In later retrievals, the tissue consisted of fibrosis often with organizing or lytic thrombi. Fibrosis showed different stages of organization, notably early fibrocellular and later fibrosclerotic tissue. Inflammatory cells were seen (n = 4) without signs of infection. Tricuspid valve material was retrieved in 1 patient after 36 months, resulting in increased tricuspid regurgitation.

Conclusion: Our results suggest that fibrosis and thrombus adherent to LPs are common and encapsulate the LP as seen in transvenous pacemakers. LPs may adhere to the tricuspid valve or subvalvular apparatus affecting retrieval safety. The end-of-life strategy should be optimized by incorporating risk stratification for excessive fibrotic encapsulation and adhesions.
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http://dx.doi.org/10.1016/j.hrthm.2021.08.025DOI Listing
August 2021

Correction to: Cardiac hypertrophy at autopsy.

Virchows Arch 2021 Jul;479(1):95

Department of Cardiovascular Pathology, Cardiology Clinical Academic Group, Molecular and Clinical Sciences Research Institute, St George's Medical School, London, UK.

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http://dx.doi.org/10.1007/s00428-021-03118-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8329813PMC
July 2021

Cardiac hypertrophy at autopsy.

Virchows Arch 2021 Jul 19;479(1):79-94. Epub 2021 Mar 19.

Department of Cardiovascular Pathology, Cardiology Clinical Academic Group, Molecular and Clinical Sciences Research Institute, St George's Medical School, London, UK.

Since cardiac hypertrophy may be considered a cause of death at autopsy, its assessment requires a uniform approach. Common terminology and methodology to measure the heart weight, size, and thickness as well as a systematic use of cut off values for normality by age, gender, and body weight and height are needed. For these reasons, recommendations have been written on behalf of the Association for European Cardiovascular Pathology. The diagnostic work up implies the search for pressure and volume overload conditions, compensatory hypertrophy, storage and infiltrative disorders, and cardiomyopathies. Although some gross morphologic features can point to a specific diagnosis, systematic histologic analysis, followed by possible immunostaining and transmission electron microscopy, is essential for a final diagnosis. If the autopsy is carried out in a general or forensic pathology service without expertise in cardiovascular pathology, the entire heart (or pictures) together with mapped histologic slides should be sent for a second opinion to a pathologist with such an expertise. Indication for postmortem genetic testing should be integrated into the multidisciplinary management of sudden cardiac death.
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http://dx.doi.org/10.1007/s00428-021-03038-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8298245PMC
July 2021

An updated approach to sudden cardiac death, the AECVP perspective.

Int J Legal Med 2021 07 18;135(4):1555-1557. Epub 2021 Mar 18.

Cardiovascular Pathology Unit, Department of Cardiac, Thoracic and Vascular Sciences and Public Health, University of Padua, Padua, Italy.

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http://dx.doi.org/10.1007/s00414-021-02551-wDOI Listing
July 2021

Viral presence and immunopathology in patients with lethal COVID-19: a prospective autopsy cohort study.

Lancet Microbe 2020 Nov 25;1(7):e290-e299. Epub 2020 Sep 25.

Department of Pathology, Amsterdam University Medical Centers (UMC), VU University Amsterdam, Amsterdam, Netherlands.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) targets multiple organs and causes severe coagulopathy. Histopathological organ changes might not only be attributable to a direct virus-induced effect, but also the immune response. The aims of this study were to assess the duration of viral presence, identify the extent of inflammatory response, and investigate the underlying cause of coagulopathy.

Methods: This prospective autopsy cohort study was done at Amsterdam University Medical Centers (UMC), the Netherlands. With informed consent from relatives, full body autopsy was done on 21 patients with COVID-19 for whom autopsy was requested between March 9 and May 18, 2020. In addition to histopathological evaluation of organ damage, the presence of SARS-CoV-2 nucleocapsid protein and the composition of the immune infiltrate and thrombi were assessed, and all were linked to disease course.

Findings: Our cohort (n=21) included 16 (76%) men, and median age was 68 years (range 41-78). Median disease course (time from onset of symptoms to death) was 22 days (range 5-44 days). In 11 patients tested for SARS-CoV-2 tropism, SARS-CoV-2 infected cells were present in multiple organs, most abundantly in the lungs, but presence in the lungs became sporadic with increased disease course. Other SARS-CoV-2-positive organs included the upper respiratory tract, heart, kidneys, and gastrointestinal tract. In histological analyses of organs (sampled from nine to 21 patients per organ), an extensive inflammatory response was present in the lungs, heart, liver, kidneys, and brain. In the brain, extensive inflammation was seen in the olfactory bulbs and medulla oblongata. Thrombi and neutrophilic plugs were present in the lungs, heart, kidneys, liver, spleen, and brain and were most frequently observed late in the disease course (15 patients with thrombi, median disease course 22 days [5-44]; ten patients with neutrophilic plugs, 21 days [5-44]). Neutrophilic plugs were observed in two forms: solely composed of neutrophils with neutrophil extracellular traps (NETs), or as aggregates of NETs and platelets..

Interpretation: In patients with lethal COVID-19, an extensive systemic inflammatory response was present, with a continued presence of neutrophils and NETs. However, SARS-CoV-2-infected cells were only sporadically present at late stages of COVID-19. This suggests a maladaptive immune response and substantiates the evidence for immunomodulation as a target in the treatment of severe COVID-19.

Funding: Amsterdam UMC Corona Research Fund.
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http://dx.doi.org/10.1016/S2666-5247(20)30144-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7518879PMC
November 2020

Pathological features of COVID-19-associated myocardial injury: a multicentre cardiovascular pathology study.

Eur Heart J 2020 Oct;41(39):3827-3835

Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.

Aims: Coronavirus disease 2019 (COVID-19) due to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has been associated with cardiovascular features of myocardial involvement including elevated serum troponin levels and acute heart failure with reduced ejection fraction. The cardiac pathological changes in these patients with COVID-19 have yet to be well described.

Methods And Results: In an international multicentre study, cardiac tissue from the autopsies of 21 consecutive COVID-19 patients was assessed by cardiovascular pathologists. The presence of myocarditis, as defined by the presence of multiple foci of inflammation with associated myocyte injury, was determined, and the inflammatory cell composition analysed by immunohistochemistry. Other forms of acute myocyte injury and inflammation were also described, as well as coronary artery, endocardium, and pericardium involvement. Lymphocytic myocarditis was present in 3 (14%) of the cases. In two of these cases, the T lymphocytes were CD4 predominant and in one case the T lymphocytes were CD8 predominant. Increased interstitial macrophage infiltration was present in 18 (86%) of the cases. A mild pericarditis was present in four cases. Acute myocyte injury in the right ventricle, most probably due to strain/overload, was present in four cases. There was a non-significant trend toward higher serum troponin levels in the patients with myocarditis compared with those without myocarditis. Disrupted coronary artery plaques, coronary artery aneurysms, and large pulmonary emboli were not identified.

Conclusions: In SARS-CoV-2 there are increased interstitial macrophages in a majority of the cases and multifocal lymphocytic myocarditis in a small fraction of the cases. Other forms of myocardial injury are also present in these patients. The macrophage infiltration may reflect underlying diseases rather than COVID-19.
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http://dx.doi.org/10.1093/eurheartj/ehaa664DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7543528PMC
October 2020

Germline variants in HEY2 functional domains lead to congenital heart defects and thoracic aortic aneurysms.

Genet Med 2021 01 21;23(1):103-110. Epub 2020 Aug 21.

Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.

Purpose: In this study we aimed to establish the genetic cause of a myriad of cardiovascular defects prevalent in individuals from a genetically isolated population, who were found to share a common ancestor in 1728.

Methods: Trio genome sequencing was carried out in an index patient with critical congenital heart disease (CHD); family members had either exome or Sanger sequencing. To confirm enrichment, we performed a gene-based association test and meta-analysis in two independent validation cohorts: one with 2685 CHD cases versus 4370 . These controls were also ancestry-matched (same as FTAA controls), and the other with 326 cases with familial thoracic aortic aneurysms (FTAA) and dissections versus 570 ancestry-matched controls. Functional consequences of identified variants were evaluated using expression studies.

Results: We identified a loss-of-function variant in the Notch target transcription factor-encoding gene HEY2. The homozygous state (n = 3) causes life-threatening congenital heart defects, while 80% of heterozygous carriers (n = 20) had cardiovascular defects, mainly CHD and FTAA of the ascending aorta. We confirm enrichment of rare risk variants in HEY2 functional domains after meta-analysis (MetaSKAT p = 0.018). Furthermore, we show that several identified variants lead to dysregulation of repression by HEY2.

Conclusion: A homozygous germline loss-of-function variant in HEY2 leads to critical CHD. The majority of heterozygotes show a myriad of cardiovascular defects.
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http://dx.doi.org/10.1038/s41436-020-00939-4DOI Listing
January 2021

MiR-223-3p and miR-122-5p as circulating biomarkers for plaque instability.

Open Heart 2020 06;7(1)

Department of Vascular Medicine, Amsterdam UMC, Location AMC, The University of Amsterdam, Amsterdam, The Netherlands

Background: In this study, we discovered and validated candidate microRNA (miRNA) biomarkers for coronary artery disease (CAD).

Method: Candidate tissue-derived miRNAs from atherosclerotic plaque material in patients with stable coronary artery disease (SCAD) (n=14) and unstable coronary artery disease (UCAD) (n=25) were discovered by qPCR-based arrays. We validated differentially expressed miRNAs, along with seven promising CAD-associated miRNAs from the literature, in the serum of two large cohorts (n=395 and n=1000) of patients with SCAD and UCAD and subclinical atherosclerosis (SubA) and controls, respectively.

Result: From plaque materials (discovery phase), miR-125b-5p and miR-193b-3p were most upregulated in SCAD, whereas miR-223-3p and miR-142-3p were most upregulated in patients with UCAD. Subsequent validation in serum from patients with UCAD, SCAD, SubA and controls demonstrated significant upregulation of miR-223-3p, miR-133a-3p, miR-146-3p and miR-155-5p. The ischaemia-related miR-499-5p was also highly upregulated in patients with UCAD compared with the other groups (SCAD OR 20.63 (95% CI 11.16 to 38.15), SubA OR 96.10 (95% CI 40.13 to 230.14) and controls OR 15.73 (95% CI 7.80 to 31.72)). However, no significant difference in miR-499-5p expression was observed across SCAD, SubA and controls. MiR-122-5p was the only miRNA to be significantly upregulated in the serum of both patients with UCAD and SCAD.

Conclusion: In conclusion, miR-122-5p and miR-223-3p might be markers of plaque instability.
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http://dx.doi.org/10.1136/openhrt-2019-001223DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7269547PMC
June 2020

Authors' Response to Letter to the Editor on "Unidentified Variables May Account for Variability in Multiplexing Results".

J Histochem Cytochem 2020 05;68(5):355-356

Department of Dermatology, Amsterdam University Medical Centers, location AMC, University of Amsterdam, Amsterdam, The Netherlands.

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http://dx.doi.org/10.1369/0022155420925082DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7226621PMC
May 2020

Autopsy in adults with congenital heart disease (ACHD).

Virchows Arch 2020 Jun 7;476(6):797-820. Epub 2020 Apr 7.

Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands.

The adult congenital heart diseases (ACHD) population is exceeding the pediatric congenital heart diseases (CHD) population and is progressively expanding each year, representing more than 90% of patients with CHD. Of these, about 75% have undergone surgical and/or percutaneous intervention for palliation or correction. Autopsy can be a very challenging procedure in ACHD patients. The approach and protocol to be used may vary depending on whether the pathologists are facing native disease without surgical or percutaneous interventions, but with various degrees of cardiac remodeling, or previously palliated or corrected CHD. Moreover, interventions for the same condition have evolved over the last decades, as has perioperative myocardial preservations and postoperative care, with different long-term sequelae depending on the era in which patients were operated on. Careful clinicopathological correlation is, thus, required to assist the pathologist in performing the autopsy and reaching a diagnosis regarding the cause of death. Due to the heterogeneity of the structural abnormalities, and the wide variety of surgical and interventional procedures, there are no standard methods for dissecting the heart at autopsy. In this paper, we describe the most common types of CHDs that a pathologist could encounter at autopsy, including the various types of surgical and percutaneous procedures and major pathological manifestations. We also propose a practical systematic approach to the autopsy of ACHD patients.
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http://dx.doi.org/10.1007/s00428-020-02779-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7272495PMC
June 2020

Etosis, rather than apoptosis or cell proliferation, typifies thrombus progression - An immunohistochemical study of coronary aspirates.

Int J Cardiol Heart Vasc 2020 Feb 25;26:100439. Epub 2019 Nov 25.

Department of Pathology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, Netherlands.

Background: Coronary thrombosis is a process with unpredictable clinical outcome. Changes of thrombus composition overtime influence tissue repair and stabilization. We investigated rates of cell deaths and cell proliferation at different time points after initiation of thrombosis.

Methods: Thrombectomy aspirates of 55 myocardial infarction patients were selected and histomorphologically classified as fresh (25), lytic (25), partially fibrocellular (10), completely fibrocellular (10). Paraffin sections were immunostained with anti-(cleaved) caspase-3/Casp3 (apoptosis), Citrullinated histone/CitH 3 (etosis), C-reactive protein/CRP and Ki67 (proliferation) in combination with either Feulgen counterstaining (DNA) or cell markers for granulocytes, macrophages, SMCs, platelets and endothelium. Rates of apoptosis, etosis and proliferation were measured as a percentage of total number of immunopositive pixels versus total number of DNA positive pixels, while co-localization with cell markers was assessed by digital image analysis.

Results: Positive staining of CitH3 was observed more frequently (93%) than Casp3 (70%), Ki67 (79%) or CRP (59%) (p < 0.05). Moreover, rate of etosis, found in granulocytes and macrophages, differed significantly among thrombi of different age, being higher in lytic (12.82) than in fresh (8.52) and late-organized (2.75) (p < 0.05). Such differences were not observed for the rates of apoptosis or cell proliferation related to thrombus age. CRP staining was present in fresh, lytic and organized thrombi, but did not reliably identify necrotic areas.

Conclusions: Different patterns of cell death and cell proliferation are noticed during progression of coronary thrombus overtime, but with significant differences for only etosis. Etosis could potentially serve as a biomarker for thrombus instability with clinical significance.
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http://dx.doi.org/10.1016/j.ijcha.2019.100439DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7046519PMC
February 2020

Comparison of Two Different Immunohistochemical Quadruple Staining Approaches to Identify Innate Lymphoid Cells in Formalin-fixed Paraffin-embedded Human Tissue.

J Histochem Cytochem 2020 02 27;68(2):127-138. Epub 2019 Dec 27.

Department of Dermatology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands.

Lack of specific markers for innate lymphoid cells (ILCs) limit our knowledge on their spatial organization in situ. We compared two quadruple-color staining protocols for detection of the three principal human ILC subsets in formalin-fixed paraffin-embedded specimens. ILC subset-associated archetypical transcription factors (TFs) T-bet, GATA3, and RORγt were used as positive identifiers in combination with lymphoid lineage markers to exclude non-ILCs. One method ("virtual quadruple staining") comprised of iterative single stainings on the same section performing digital scanning and subsequent immunoglobulin and chromogen stripping after each staining round. The second technique ("true-color quadruple staining") comprised sequential double stainings with permanent colors. Both protocols appeared suitable for accurate detection of each ILC subset, and as added result, concomitant visualization of their T cell subset counterpart. Only true-color quadruple staining enabled simultaneous detection of all three ILC subsets within one section. Furthermore, we found that type 3 and type 1 ILCs (ILC1s) represent the major subsets in colon and that part of the ILC1s typically colocalizes with blood vessels. Our data highlight the utility of TFs combined with lineage markers for the identification of ILC subsets and proposed workflow opens the way to gain deeper insight of their anatomical distribution.
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http://dx.doi.org/10.1369/0022155419897257DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7003497PMC
February 2020

Diagnosis of myocardial infarction at autopsy: AECVP reappraisal in the light of the current clinical classification.

Virchows Arch 2020 Feb 14;476(2):179-194. Epub 2019 Sep 14.

Amsterdam UMC, Academic Medical Center, Meibergdreef 9, 1105AZ, Amsterdam, The Netherlands.

Ischemic heart disease is one of the leading causes of morbidity and death worldwide. Consequently, myocardial infarctions are often encountered in clinical and forensic autopsies, and diagnosis can be challenging, especially in the absence of an acute coronary occlusion. Precise histopathological identification and timing of myocardial infarction in humans often remains uncertain while it can be of crucial importance, especially in a forensic setting when third person involvement or medical responsibilities are in question. A proper post-mortem diagnosis requires not only up-to-date knowledge of the ischemic coronary and myocardial pathology, but also a correct interpretation of such findings in relation to the clinical scenario of the deceased. For these reasons, it is important for pathologists to be familiar with the different clinically defined types of myocardial infarction and to discriminate myocardial infarction from other forms of myocardial injury. This article reviews present knowledge and post-mortem diagnostic methods, including post-mortem imaging, to reveal the different types of myocardial injury and the clinical-pathological correlations with currently defined types of myocardial infarction.
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http://dx.doi.org/10.1007/s00428-019-02662-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7028821PMC
February 2020

Feasibility of mapping and cannulation of the porcine epicardial lymphatic system for sampling and decompression in heart failure research.

J Clin Transl Res 2019 Jan 18;4(2):105-112. Epub 2018 Jul 18.

Department of Pathology, Academic Medical Center, Amsterdam, the Netherlands.

Background And Aim: The cardiac lymphatic system drains excess fluid from the cardiac interstitium. Any impairment or dysfunction of the lymph structures can result in the accumulation of interstitial fluid, and may lead to edema and eventually cardiac dysfunction. Lymph originates directly from the interstitium and carries real-time information about the metabolic state of cells in specific regions of the heart. The detailed anatomy of the epicardial lymphatic system in individuals is broadly unknown. Generally, the epicardial lymphatic system is not taken into consideration during heart surgery. This study investigates the feasibility of detailed mapping and cannulation of the porcine epicardial lymphatic system for use in preservation of explanted hearts and heart failure studies in pigs and humans.

Methods: The anatomy of the epicardial lymphatic systems of forty pig hearts was studied and documented. Using a 27 G needle, India ink was introduced directly into the epicardial lymphatic vessels in order to visualise them. Based on the anatomical findings thus obtained, two cannulation regions for the left and right principal trunks were identified. These regions were cannulated with a 26 G intravenous Venflon cannula-over-needle, and a Galeo Hydro Guide F014 wire was used to verify that the lumen was patent.

Results: The main epicardial lymphatic collectors were found to follow the main coronary arteries. Most of the lymph vessels drained into the left ventricular trunk, which evacuates fluid from the left heart and also partially from the right heart. The right trunk was often found to drain into the left trunk anterior basally. Right heart drainage was highly variable compared to the left. In addition, the overall cannulation success rate of the selected cannulation sites was only 57%.

Conslusions: Mapping of the porcine epicardial lymphatic anatomy is feasible. The right ventricular drainage system had a higher degree of variability than the left, and the right cardiac lymph system was found to be partially cleared through the left lymphatic trunk. To improve cannulation success rate, we proposed two sites for cannulation based on these findings and the use of Venflon cannulas (26 G) for cannulation and lymph collection. This method might be helpful for future studies that focus on biochemical sample analysis and decompression.

Relevance For Patients: Real-time biochemical assessment and decompression of lymph may contribute to the understanding of heart failure and eventually result in preventive measures. First its relevance should be established by additional research in both arrested and working porcine hearts. Imaging and mapping of the epicardial lymphatics may enable sampling and drainage and contribute to the prevention or treatment of heart failure. We envision that this approach may be considered in patients with a high risk of postoperative left and right heart failure during open-heart surgery.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6412608PMC
January 2019

Extracellular traps derived from macrophages, mast cells, eosinophils and neutrophils are generated in a time-dependent manner during atherothrombosis.

J Pathol 2019 04 25;247(4):505-512. Epub 2019 Jan 25.

Department of Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.

Extracellular traps generated by neutrophils contribute to thrombus progression in coronary atherosclerotic plaques. It is not known whether other inflammatory cell types in coronary atherosclerotic plaque or thrombus also release extracellular traps. We investigated their formation by macrophages, mast cells, and eosinophils in human coronary atherosclerosis, and in relation to the age of thrombus of myocardial infarction patients. Coronary arteries with thrombosed or intact plaques were retrieved from patients who died from myocardial infarction. In addition, thrombectomy specimens from patients with myocardial infarction were classified histologically as fresh, lytic or organised. Neutrophil and macrophage extracellular traps were identified using sequential triple immunostaining of CD68, myeloperoxidase, and citrullinated histone H3. Eosinophil and mast cell extracellular traps were visualised using double immunostaining for eosinophil major basic protein or tryptase, respectively, and citrullinated histone H3. Single- and double-stained immunopositive cells in the plaque, adjacent adventitia, and thrombus were counted. All types of leucocyte-derived extracellular traps were present in all thrombosed plaques, and in all types of the in vivo-derived thrombi, but only to a much lower extent in intact plaques. Neutrophil traps, followed by macrophage traps, were the most prominent types in the autopsy series of atherothrombotic plaques, including the adventitia adjacent to thrombosed plaques. In contrast, macrophage traps were more numerous than neutrophil traps in intact plaques (lipid cores) and organised thrombi. Mast cell and eosinophil extracellular traps were also present, but sparse in all instances. In conclusion, not only neutrophils but also macrophages, eosinophils, and mast cells are sources of etosis involved in evolving coronary thrombosis. Neutrophil traps dominate numerically in early thrombosis and macrophage traps in late (organising) thrombosis, implying that together they span all the stages of thrombus progression and maturation. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
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http://dx.doi.org/10.1002/path.5212DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6590313PMC
April 2019

Protease-activated receptors are potential regulators in the development of arterial endofibrosis in high-performance athletes.

J Vasc Surg 2019 04 9;69(4):1243-1250. Epub 2018 Oct 9.

Laboratory for Clinical Thrombosis and Hemostasis, Department of Internal Medicine, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands.

Objective: High-performance athletes can develop symptomatic arterial flow restriction during exercise caused by endofibrosis. The pathogenesis is poorly understood; however, coagulation enzymes, such as tissue factor (TF) and coagulation factor Xa, might contribute to the fibrotic process, which is mainly regulated through activation of protease-activated receptors (PARs). Therefore, the aim of this explorative study was to evaluate the presence of coagulation factors and PARs in endofibrotic tissue, which might be indicative of their potential role in the natural development of endofibrosis.

Methods: External iliac arterial specimens with endofibrosis (n = 19) were collected during surgical interventions. As control, arterial segments of the external iliac artery (n = 20) were collected post mortem from individuals with no medical history of cardiovascular disease who donated their body to medical science. Arteries were paraffinized and cut in tissue sections for immunohistochemical analysis. Positive staining within lesions was determined with ImageJ software (National Institutes of Health, Bethesda, Md).

Results: Endofibrotic segments contained a neointima, causing intraluminal stenosis, which was highly positive for collagen (+150%; P < .01) and elastin (+148%; P < .01) in comparison with controls. Intriguingly, endofibrosis was not limited to the intima because collagen (+213%) and elastin (+215%) were also significantly elevated in the media layer of endofibrotic segments. These findings were accompanied by significantly increased α-smooth muscle actin-positive cells, morphologically compatible with the presence of myofibroblasts. In addition, PAR1 and PAR4 and the membrane receptor TF were increased as well as coagulation factor X.

Conclusions: We showed that myofibroblasts and the accompanying collagen and elastin synthesis might be key factors in the development of endofibrosis. The special association with increased presence of PARs, factor X, and TF suggests that protease-mediated cell signaling could be a contributing component in the mechanisms leading to endofibrosis.
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http://dx.doi.org/10.1016/j.jvs.2018.05.220DOI Listing
April 2019

Patched-2 functions to limit Patched-1 deficient skin cancer growth.

Cell Oncol (Dordr) 2018 Aug 4;41(4):427-437. Epub 2018 Jun 4.

Laboratory for Experimental Oncology and Radiobiology, Center for Experimental and Molecular Medicine, Cancer Center Amsterdam and Academic Medical Center, Meibergdreef 9, 1105AZ, Amsterdam, The Netherlands.

Purpose: Basal cell carcinoma (BCC) is one of the most common skin cancers, and is typically driven by an aberrantly activated Hedgehog (Hh) pathway. The Hh pathway is regulated by interactions between the Patched-1 (Ptch1) and Smoothened (Smo) receptors. Smo is an activating receptor and is subject to inhibition by Ptch1. Following ligand binding to Ptch1, its inhibitory action is relieved and pathway activation occurs. This receptor interaction is pivotal to restraining uncontrolled cellular growth. Both receptors have been found to be frequently mutated in BCCs. Ptch2 is a Ptch1 paralog that exhibits overlapping functions in both normal development and tissue homeostasis. As yet, its contribution to cancer growth is poorly defined. Here we set out to assess how Ptch2 inhibits BCC growth.

Methods: We used several in vitro readouts for transcriptional and chemotactic Hh signaling in BCC-derived ASZ001 cells, and a novel xenograft model to assess in vivo BCC tumor growth. Gene editing by TALEN was used to untangle the different Ptch2-dependent responses to its ligand sonic hedgehog (Shh).

Results: We first defined the signaling competence of Ptch2 in Ptch1-deficient ASZ001 cells in vitro, and found that Ptch2 ligand binding drives their migration rather than eliciting a transcriptional response. We found that subsequent targeting of Ptch2 abrogated the chemotaxic effect. Next, we tested the contribution of Ptch2 to in vivo tumor growth using a xenograft model and found that reduced Ptch function results in increased tumor growth, but that selective pressure appatently acts against complete Ptch2 ablation.

Conclusions: We conclude that like Ptch1, Ptch2 exerts a tumor-suppressive function in BCC cells, and that after targeting of both paralogs, ligand-independent activation of the Hh pathway contributes to tumor growth.
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http://dx.doi.org/10.1007/s13402-018-0381-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6105176PMC
August 2018

A common co-morbidity modulates disease expression and treatment efficacy in inherited cardiac sodium channelopathy.

Eur Heart J 2018 08;39(31):2898-2907

Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, University of Amsterdam, Meibergdreef 15, PO Box 22660, 1100 DD Amsterdam, The Netherlands.

Aims: Management of patients with inherited cardiac ion channelopathy is hindered by variability in disease severity and sudden cardiac death (SCD) risk. Here, we investigated the modulatory role of hypertrophy on arrhythmia and SCD risk in sodium channelopathy.

Methods And Results: Follow-up data was collected from 164 individuals positive for the SCN5A-1795insD founder mutation and 247 mutation-negative relatives. A total of 38 (obligate) mutation-positive patients died suddenly or suffered life-threatening ventricular arrhythmia. Of these, 18 were aged >40 years, a high proportion of which had a clinical diagnosis of hypertension and/or cardiac hypertrophy. While pacemaker implantation was highly protective in preventing bradycardia-related SCD in young mutation-positive patients, seven of them aged >40 experienced life-threatening arrhythmic events despite pacemaker treatment. Of these, six had a diagnosis of hypertension/hypertrophy, pointing to a modulatory role of this co-morbidity. Induction of hypertrophy in adult mice carrying the homologous mutation (Scn5a1798insD/+) caused SCD and excessive conduction disturbances, confirming a modulatory effect of hypertrophy in the setting of the mutation. The deleterious effects of the interaction between hypertrophy and the mutation were prevented by genetically impairing the pro-hypertrophic response and by pharmacological inhibition of the enhanced late sodium current associated with the mutation.

Conclusion: This study provides the first evidence for a modulatory effect of co-existing cardiac hypertrophy on arrhythmia risk and treatment efficacy in inherited sodium channelopathy. Our findings emphasize the need for continued assessment and rigorous treatment of this co-morbidity in SCN5A mutation-positive individuals.
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http://dx.doi.org/10.1093/eurheartj/ehy247DOI Listing
August 2018

Neutrophil Extracellular Traps Participate in All Different Types of Thrombotic and Haemorrhagic Complications of Coronary Atherosclerosis.

Thromb Haemost 2018 06 19;118(6):1078-1087. Epub 2018 Apr 19.

Department of Pathology, Academic Medical Center, Amsterdam, The Netherlands.

Acute coronary syndromes can be initiated by either atherosclerotic fibrous cap ruptures, superficial plaque erosions or intraplaque haemorrhages (IPHs). Since neutrophil extracellular traps (NETs) display pro-inflammatory and pro-thrombotic properties, we investigated the presence, extent and distribution of neutrophils and NETs in different types of plaque complications in relation to the age of overlying thrombus mass or haemorrhage. Sixty-four paraffin-embedded coronary plaque segments of 30 acute myocardial infarction patients were retrieved from the autopsy archives, which contained 44 complicated plaques (17 IPHs, 9 erosions and 18 ruptures) and 20 intact plaques. Complicated plaques were further categorized according to the histological age of thrombus or haemorrhage. Immunohistochemistry was performed to visualize neutrophils (anti-myeloperoxidase, anti-elastase and anti-CD177) and NETs (anti-citrullinated histone-3 and anti-peptidyl-arginine-deiminase-4). The results were scored semi-quantitatively. Neutrophils and NETs were abundantly present in all types of complicated, but not in intact, plaques ( < 0.05). They were found in thrombus, haemorrhages and at the thrombus-plaque interface, with no significant differences in extent between ruptures, erosions and IPHs. Interestingly, adjacent perivascular tissue of complicated, but not of intact plaques, also contained high numbers of neutrophils and NETs ( < 0.05). In thrombus and haemorrhage of different age, neutrophils and NETs were more frequently present in non-organized (fresh) thrombi and in on-going IPHs. In conclusion, netosis is a prominent pro-thrombotic participant in all distinct types of atherothrombosis, which may facilitate the progression of thrombotic or haemorrhagic complications and thus the onset of ensuing clinical coronary ischemic syndromes.
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http://dx.doi.org/10.1055/s-0038-1641749DOI Listing
June 2018

Immunophenotypic analysis of the chronological events of tissue repair in aortic medial dissections.

Cardiovasc Pathol 2018 May - Jun;34:9-14. Epub 2018 Feb 10.

Dept. of Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105, AZ, Amsterdam, the Netherlands. Electronic address:

Acute medial dissection of aorta can occur in the context of a sudden and unexpected death. For medico-legal reasons it is important to estimate as accurately the histological age of dissections. We evaluated the additional value of a systematic application of immunohistochemistry, compared with conventional histology only, in determining chronological steps of injury and repair. Thirty two paraffin embedded specimens of aortic dissection were retrospectively allocated to one of four defined stages: acute (I), subacute (II), early organizing (III) and scarring (IV) using Hematoxylin and Eosin and Elastica van Gieson stained sections. Subsequent immunohistochemically staining was performed with the following markers: (myeloperoxidase (neutrophils), citrullinated-Histone 3 (neutrophil extracellular traps), CD68 (macrophages), CD3 (T-cells), CD31 and CD34 (endothelial cells), and smooth muscle actin. Immune stained sections were scored semi-quantitatively. Histologically, five cases were identified as stage I, 16 as II, 7 as III and 4 as IV. Additional immunostaining for smooth muscle cells and endothelial cells altered the classification in 25% of cases (all in groups II and III). Immunostaining and semi-quantitative grading of involvement of neutrophils, macrophages and NETs also provided specific distribution patterns over the 4 age categories, including unexpected involvement of the peri adventitial fat tissue. In conclusion, it appears that semi-quantitative immunohistochemistry of resident vascular wall cells, inflammatory cells and NETS represents a useful adjunct in detailed histopathological grading of the chronological age of aortic dissections.
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http://dx.doi.org/10.1016/j.carpath.2018.01.009DOI Listing
October 2018

Discrepancy between the clinical and histopathologic diagnosis of soft tissue vascular malformations.

J Am Acad Dermatol 2017 Nov 1;77(5):920-929.e1. Epub 2017 Jul 1.

Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.

Background: Soft tissue vascular malformations are generally diagnosed clinically, according to the International Society for the Study of Vascular Anomalies (ISSVA) classification. Diagnostic histopathologic examination is rarely performed.

Objective: We sought to evaluate the validity of the current diagnostic workup without routinely performed diagnostic histopathology.

Methods: We retrospectively determined whether there were discrepancies between clinical and histopathologic diagnoses of patients with clinically diagnosed vascular malformations undergoing therapeutic surgical resections in our center (2000-2015). Beforehand, a pathologist revised the histopathologic diagnoses according to the ISSVA classification.

Results: Clinical and histopathologic diagnoses were discrepant in 57% of 142 cases. In these cases, the pathologist indicated the diagnosis was not at all a vascular malformation (n = 24; 17%), a completely different type of vascular malformation (n = 26; 18%), or a partially different type with regard to the combination of vessel-types involved (n = 31; 22%). Possible factors associated with the discrepancies were both clinician-related (eg, diagnostic uncertainty) and pathology-related (eg, lack of immunostaining).

Limitations: Retrospective analysis of a subgroup of patients undergoing surgery.

Conclusion: The large discrepancy between clinical and histopathologic diagnoses raises doubt about the validity of the current diagnostic workup for vascular malformations. Clear clinical and histopathologic diagnostic criteria might be essential for a uniform diagnosis.
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http://dx.doi.org/10.1016/j.jaad.2017.03.045DOI Listing
November 2017

Intraleaflet hemorrhages are a common finding in symptomatic aortic and mitral valves.

Cardiovasc Pathol 2017 Sep - Oct;30:12-18. Epub 2017 Jun 17.

Department of Pathology, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands. Electronic address:

Introduction: Intraleaflet hemorrhage (ILH) has been reported to occur in calcified degenerated aortic valves. At present, no such information is available for mitral valves or for other types of valvular disease. We examined the prevalence, age, and potential source of ILH in a consecutive series of surgically removed aortic and mitral valves, and related the findings to specific types of heart valve pathology.

Methods: A total of 105 aortic (n=85) and mitral (n=20) valves were retrieved from 100 symptomatic patients. Pathological diagnosis was made on photographic images and histology. Presence, extent, and age of ILH; its possible association with calcification; microvessels; and microvascular leakage were assessed with conventional and immunohistochemical staining methods and related to the type of underlying valvular disease.

Results: Pathological diagnosis revealed degenerative aortic valve disease (n=70), postinflammatory disease (n=16), endocarditis (n=12), myxoid degenerative mitral valve disease (n=6), and one normal valve. ILH was found in 86% of aortic and 75% of mitral valves. Microvessels were present in 91% of all valves. Microvascular leakage was noted in 70% of aortic and 84% of mitral valves; in both groups, colocalization with ILH was found in 48%. Most aortic valves (91%) contained calcium deposits, of which 54% showed colocalization with ILH. In 66% of valves with ILH, a combination of recent hemorrhage and iron deposits was seen, indicating an ongoing process of episodic hemorrhages.

Conclusion: The prevalence of ILH is very high in resected heart valves. Both aortic and mitral valves showed an association of ILH with microvessels, microvascular leakage, and calcifications. We speculate that repetitive microvascular-leakage-related ILH may contribute to valve dysfunction on the (very) long term.
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http://dx.doi.org/10.1016/j.carpath.2017.06.002DOI Listing
May 2018

The change in circulating galectin-3 predicts absence of atrial fibrillation after thoracoscopic surgical ablation.

Europace 2018 05;20(5):764-771

Department of Cardiology, Experimental Cardiology and Cardiothoracic Surgery, Heart Center, Academic Medical Center, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands.

Aims: Galectin-3 (Gal-3) is an important mediator of cardiac fibrosis, particularly in heart failure. Increased Gal-3 concentration (Gal-3), associated with increased risk of developing atrial fibrillation (AF), may reflect atrial fibrotic remodelling underlying AF progression. We aimed to investigate whether the change in serum Gal-3 reflects alterations of the arrhythmogenic atrial substrate following thoracoscopic AF surgery, and predicts absence of AF.

Methods And Results: Consecutive patients undergoing thoracoscopic AF surgery were included. Left atrial appendages (LAAs) and serum were collected during surgery and serum again 6 months thereafter. Gal-3 was determined in tissue and serum. Interstitial collagen in the LAA was quantified using Picrosirius red staining. Ninety-eight patients (76% male, mean age 60 ± 9 years) underwent thoracoscopic surgery for advanced AF. Patients with increased Gal-3 after ablation compared to baseline had a higher recurrence rate compared to patients with decreased or unchanged Gal-3 (HR 2.91, P = 0.014). These patients more frequently had persistent AF, longer AF duration and thick atrial collagen strands (P = 0.049). At baseline, Gal-3 was similar between patients with and without AF recurrence: 14.8 ± 3.9 µg/L vs. 13.7 ± 3.7 µg/L, respectively in serum (P = 0.16); 94.5 ± 19.4 µg/L vs. 93.3 ± 30.8µg/L, respectively in atrial myocardium (P = 0.83). There was no correlation between serum Gal-3 and left atrial Gal-3 (P = 0.20), nor between serum Gal-3 and the percentage of fibrosis in LAA (P = 0.18).

Conclusion: The change of circulating Gal-3, rather than its baseline value, predicts AF recurrence after thoracoscopic ablation. Patients in whom Gal-3 increases after ablation have a high recurrence rate reflecting ongoing profibrotic signalling, irrespective of arrhythmia continuation.
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http://dx.doi.org/10.1093/europace/eux090DOI Listing
May 2018

Sudden aortic death-proposal for a comprehensive diagnostic approach in forensic and in clinical pathology practice.

Int J Legal Med 2017 Nov 27;131(6):1565-1572. Epub 2017 Feb 27.

University Hospital of Lausanne, University Center of Legal Medicine, Lausanne-Geneva, Chemin de la Vulliette 4, 1000, Lausanne 25, Switzerland.

Backgrounds: Aortic rupture or dissection as immediate cause of sudden death is encountered in forensic and clinical autopsy practice. Despite a common denominator of 'sudden aortic death' (SAD), we expect that in both settings the diagnostic workup, being either primarily legal or primarily disease related, differs substantially, which may affect the eventual diagnoses.

Methods: We retrospectively reviewed case records of deceased persons who fitted a diagnosis of SAD in the continuous autopsy cohorts in a forensic (Suisse) and a clinical setting (The Netherlands). Clinical characteristics, data from post-mortem imaging, tissue blocks for histological analysis and results of ancillary studies were reviewed for its presence and outcome.

Results: SAD was found in 7.7% in the forensic versus 2.2% in the clinical autopsies. In the forensic setting, autopsy was always combined with post-mortem imaging, showing variable outcome on detection of aortic disruption and/or pericardial bleeding. Histology of aorta was performed in 12/35 cases, mostly in the natural deaths. In the clinical setting, histology of the aorta was available in all cases, but post-mortem imaging in none. In both settings, underlying aortic disease was mostly cystic medial degeneration, atherosclerosis or a combination of both, with occasional rare unexpected diagnosis. Also in both, a genetic cause of aortic dissection was revealed in a minority (three cases).

Conclusion: Sudden aortic death (SAD) is more commonly encountered in a forensic than in a clinical setting. Major differences in the approach of SAD between these settings coincide with similarities in causes of death and underlying diseases. To ensure a correct diagnosis, we recommend that the investigation of SAD includes a study of the medical history, a full autopsy with histology of major organs including aorta, and storage of material for toxicological and genetic testing. Post-mortem radiological examination, useful for documentation and screening purposes, is feasible as non-invasive alternative when autopsy is not possible, but cannot substitute a full autopsy.
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http://dx.doi.org/10.1007/s00414-017-1560-3DOI Listing
November 2017

Intravascular Lipiodol Presenting as an Atrial Mass.

Ann Thorac Surg 2017 Mar;103(3):e231-e233

Department of Pathology, Academic Medical Center, Amsterdam, The Netherlands. Electronic address:

A 68-year-old woman, previously treated with embolization of the thoracic duct with Lipiodol (an ethiodized oil injection) and cyanoacrylate glue (a topical tissue adhesive), was admitted with an asymptomatic mass in the inferior vena cava (IVC) and right atrium. The mass was surgically removed, and pathologic analysis revealed a Lipiodol-containing thrombus. To our knowledge, this is the first clinicopathologic report of Lipiodol-induced thrombus presenting as an intracavitary mass.
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http://dx.doi.org/10.1016/j.athoracsur.2016.08.025DOI Listing
March 2017

CD45 is a more sensitive marker than CD3 to diagnose lymphocytic myocarditis in the endomyocardium.

Hum Pathol 2017 Apr 23;62:83-90. Epub 2016 Dec 23.

Department of Pathology, VU University Medical Center, 1081 HV Amsterdam, the Netherlands; ICaR-VU, Institute for Cardiovascular Research, VU University Medical Center, 1081 HV Amsterdam, the Netherlands.

To diagnose lymphocytic myocarditis (LM), immunohistopathological examination of endomyocardial biopsies (EMBs) is used with a cutoff value of at least 14 leukocytes per mm, composed of CD3- and CD68-positive cells. We hypothesized that a more common leukocyte marker, CD45, instead of CD3 could increase the diagnostic sensitivity. Hearts of mice with acute viral myocarditis (n = 9) and of controls (n = 7) and the EMB sampling area of the left ventricular posterior wall (LVPW) obtained from autopsied hearts of patients diagnosed with LM (n = 18) and controls (n = 6) were stained with anti-CD68, anti-CD3, and anti-CD45. When applying the threshold of at least 14 leukocytes per mm, 33% of the mice would be diagnosed with LM with the use of CD3CD68 and 89% with the use of CD45CD68. In the EMB sampling area of autopsied hearts, using the cutoff value of at least 14 leukocytes per mm, CD3CD68 could only confirm 17% of the diagnosis of LM, whereas CD45CD68 could confirm 50% of the LM cases. Moreover, we compared inflammation in the EMB sampling area of the LVPW to the remaining myocardium of the LVPW and observed a significant increase of CD45CD68 cells per mm in patients with LM. In conclusion, the use of the common leukocyte marker CD45 increases the sensitivity of the diagnosis of LM. Furthermore, the inflammatory infiltrate in the EMB sampling area is significantly increased compared with the remaining LVPW, indicating that the sampling area constitutes the highest chance for histological diagnosis of LM.
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http://dx.doi.org/10.1016/j.humpath.2016.11.006DOI Listing
April 2017

Excessive trabeculations in noncompaction do not have the embryonic identity.

Int J Cardiol 2017 Jan 9;227:325-330. Epub 2016 Nov 9.

Department of Anatomy, Embryology & Physiology, Academic Medical Center, University of Amsterdam, The Netherlands.

Background: Ventricular noncompaction is characterized by excessive trabeculations and is associated with heart failure. The lesion is hypothesized to result from failed compaction and thus retention of embryonic trabeculations. Here, we assess for the first time the identity of trabeculations in noncompaction to test whether noncompacted hearts show retention of embryonic trabeculations.

Methods: Using immunohistochemistry, we analyzed cardiac sections of the heart of a control embryo, 3 cases of fetal noncompaction (a set of twins and an unrelated fetus) and 3 fetal hearts without noncompaction.

Results: In the embryo, the ventricular trabeculations strongly expressed ANF/NPPA whereas the compact wall did not. In the noncompaction hearts, trabeculations constituted an excessively thick layer. In noncompaction and control fetal hearts alike, however, only a miniscule subset of sub-endocardial myocardium of the trabeculations most proximal to the central ventricular lumen exhibited strong expression of ANF/NPPA, representing Purkinje myocardium. The trabeculations of both fetal control and noncompaction hearts were ANF-negative and orders of magnitude wider than those of the embryo. Both the compact and noncompaction trabeculated myocardium were rich in coronary vasculature. Like embryonic trabeculations, the ANF Purkinje myocardium had little if any vasculature.

Conclusion: The excessive trabeculations in noncompaction do not have the embryonic identity and noncompaction is probably not the result of failed compaction. We propose the lesion results from the compact wall growing into the ventricular lumen in a trabecular fashion.
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http://dx.doi.org/10.1016/j.ijcard.2016.11.089DOI Listing
January 2017

Inflammatory cell content of coronary thrombi is dependent on thrombus age in patients with ST-elevation myocardial infarction.

J Cardiol 2017 01 9;69(1):394-400. Epub 2016 Nov 9.

Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, the Netherlands; Department of Pathology, VU University Medical Center, Amsterdam, the Netherlands; Department of Cardiac Surgery, VU University Medical Center, Amsterdam, the Netherlands.

Background: ST-elevation myocardial infarction (STEMI) is typically caused by an occlusive coronary thrombus. The process of intracoronary thrombus formation is poorly understood. It is known that inflammatory cells play a role in the formation and resolution of venous thrombi, however their role in coronary thrombosis is not clear. We therefore analyzed inflammatory cells in thrombi derived from patients with STEMI in relation to histologically classified thrombus age.

Methods: Thrombus aspirates of 113 patients treated with primary percutaneous coronary intervention were prospectively collected and classified (fresh, lytic, or organized) based on hematoxylin and eosin staining. The density of inflammatory cells neutrophils (MPO), monocytes/macrophages (CD68), lymphocytes (CD45), and the platelet area (CD31), were visualized using immunohistochemistry. Patients' history, medication, and laboratory data were registered.

Results: Fresh thrombi (76.1%) were the most abundant as compared to lytic (16.8%) and organized (7.1%) thrombi. Neutrophils were significantly less present in organized (169cells/mm) compared to fresh (327 cells/mm) and lytic thrombi (311 cells/mm). Monocytes/macrophages were significantly more present in lytic (471 cells/mm) than in fresh (312 cells/mm) thrombi. We additionally found that thrombi from patients aged <50 years as compared to >50 years old contained significantly more neutrophils and monocytes/macrophages irrespective of thrombus age. Furthermore platelet area was smaller in patients on aspirin again irrespective of thrombus age. No gender differences were found.

Conclusions: The composition of inflammatory cells differs with thrombus age in thrombosuction material of STEMI patients that in part depends on patient age and medication.
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http://dx.doi.org/10.1016/j.jjcc.2016.10.003DOI Listing
January 2017

Carotid plaque fissure: An underestimated source of intraplaque hemorrhage.

Atherosclerosis 2016 11 28;254:102-108. Epub 2016 Sep 28.

Department of Surgery, Division of Vascular Surgery, University of Washington, Vascular Imaging Laboratory, 850 Republican Street, Brotman Building Room 124, Seattle, WA 98019, USA.

Background And Aims: Plaque fissuring, a phenomenon morphologically distinct from the classical rupture of a thinned fibrous cap, has not been well characterized in carotid atherosclerosis. The aim of this study was to establish the prevalence of plaque fissures in advanced carotid plaques with an otherwise intact luminal surface, and to determine whether they might be a source of intraplaque hemorrhage (IPH).

Methods: We evaluated 244 surgically intact, 'en bloc' embedded, serially sectioned carotid endarterectomy specimens and included only those plaques with a grossly intact luminal surface.

Results: Among the 67 plaques with grossly intact luminal surface, cap fissure was present in 39 (58%) plaques. A total of 60 individual fissures were present, and longitudinally mean fissure length was 1.3 mm. Most fissures were found distal to the bifurcation (63%), proximal to the stenosis (88%), and in the posterior (opposite the flow divider) or lateral quadrants (80%). 36% of the fissures remained in the superficial third of the plaque. 52% extended from the lumen surface to the middle third of the plaque and 12% reached the outer third of the plaque on cross section. Fissures often occurred between two tissue planes and were connected to IPH (fresh: 63%; any type: 92%) and calcifications (43%). No correlation was found with patient characteristics such as symptom status, carotid stenosis, hypertension, diabetes, smoking and medications (statins or antiplatelet agents).

Conclusions: Plaque fissures are common in advanced carotid plaques with an otherwise grossly intact luminal surface and are associated with fresh intraplaque hemorrhage. As they occur on the interface between plaque components with different mechanical properties, further biomechanical studies are needed to unravel the underlying failure mechanisms.
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http://dx.doi.org/10.1016/j.atherosclerosis.2016.09.069DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5533085PMC
November 2016

Time dependent apoptotic rates in the evolving coronary thrombus mass of myocardial infarction patients.

Thromb Res 2016 Sep 11;145:12-7. Epub 2016 Jul 11.

Academic Medical Center, Department of Pathology, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands. Electronic address:

Aim: To study the rate of apoptotic cell death in the process of thrombus evolution after plaque rupture in myocardial infarction.

Methods: Paraffin embedded thrombosuction aspirates of 63 patients were stained with haematoxylin & eosin (H&E) to assess histologically the age of the thrombi: fresh (intact blood cells; <1day old), lytic (necrosis; 1-5days old) or organized (ingrowth of cells; >5days old). Presence of plaque constituents (atheroma including foam cells, cholesterol crystals calcifications and fibrous cap tissue) was also recorded. Immunohistochemical (double) stains with anti-caspase-3-antibody were used to visualize apoptosis and the cells involved. For the latter caspase-3 antibody was combined with cell-specific markers MPO (granulocytes), CD68 (macrophages), CD34 (endothelial cells), SMA-1 (smooth muscle cells) and a Feulgen stain (DNA). Second, the rate of apoptosis was evaluated in relation to the age of the thrombi. Platelet apoptosis was further evaluated with the use of TEM.

Results: From a total of 63 aspirates, plaque constituents were found in 33 of the aspirates, and in 15 of them lipid rich plaque tissue was the sole component. Age classification of all thrombus containing aspirates (n=48) resulted in 12 fresh (25%), 18 lytic (37.5%) and 18 organized (37.5%) thrombi. Apoptosis was more extensive in lytic thrombi than in fresh or organized thrombi (P<0.0001). Plaque-containing aspirates showed more apoptosis than aspirates without plaque (P<0.05). Immuno staining with caspase-3 antibody in combination with cell-specific markers showed that apoptosis was most extensive in MPO+ granulocytes. Caspase-3-positive platelets (CD61+ anucleate particles) were most abundant in lytic thrombi. Apoptosis in platelets was confirmed by ultrastructure.

Conclusion: This study demonstrated a significant association between thrombus age and occurrence of apoptosis of granulocytes and also platelets, with highest rates in (fragile) lytic thrombi. We propose that apoptotic cell death in athero thrombosis could potentially serve as a biomarker for thrombus instability.
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http://dx.doi.org/10.1016/j.thromres.2016.07.003DOI Listing
September 2016
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