Megakaryocytes in the Pulmonary Circulation

Scheinin, T. M.; Koivuniemi, A

doi:10.1182/blood.v22.1.82.82

Cited by 59 publications

(21 citation statements)

References 11 publications

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“…Commonly only the nuclei of MKs, denuded of cytoplasm, are seen in arterial blood [53]. Megakaryocytes can often be observed apparently stuck in lung capillaries [47,52,56]. These are usually mature forms, mostly naked nuclei [57].…”

Section: The Megakaryocyte/platelet Clump Hypothesismentioning

confidence: 99%

The aetiology of clubbing and hypertrophic osteoarthropathy

Dickinson

1993

Eur J Clin Investigation

133

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Abstract. The evidence is reviewed for the hypothesis that clubbing and hypertrophic osteoarthropathy are due to the peripheral impaction of megakaryocytes and platelet clumps in the fingers and toes, to which this particulate matter has passed in an axial stream. The normal pulmonary vascular bed retains these large particles, which fragment before entering the systemic circulation. A right-to-left shunt allows them to bypass the pulmonary vascular bed. A preliminary histological report of platelet clumps seen at necropsy in nail bed capillaries of clubbed fingers supports the hypothesis. Platelets contain and release platelet-derived growth factor, whose known effects could explain all the pathological changes in clubbing. In addition to explaining why clubbing should occur in cyanotic congenital heart disease, clubbing in sub-acute bacterial endocarditis and distal to infected arterial grafts and aneurysms can be understood in terms of platelet clumps breaking off valves or arterial walls, and passing distally. Clubbing in liver disease is associated with multiple small pulmonary arteriovenous anastomoses which allow large particles through. Hypertrophic osteoarthropathy probably shares the same mechanism, and is mainly attributable to PDGF release; but there may also be altered platelet function and an additional growth factor derived from the lungs.

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Section: The Megakaryocyte/platelet Clump Hypothesismentioning

confidence: 99%

The aetiology of clubbing and hypertrophic osteoarthropathy

Dickinson

1993

Eur J Clin Investigation

133

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“…While this could be due to the physical trauma of being trapped by the Parsortix TM filter, similar features were seen when enzymatic streptolysin O haemolysis was used to separate the megakaryocytes from other blood cells. 14 In summary, this study shows that CTCs can be extracted from the blood of some patients with metastatic carcinoma, and that routine formalin-fixed cell-block immunohistochemistry can be used to demonstrate that these CTCs have features similar to those of the tumour biopsy. Processing and examination can be done in 2 days, if prioritised, in a National Health Service district general hospital laboratory mainly using standard techniques developed for routine biopsy specimens.…”

Section: Images Of Megakaryocyte-like Cells Have Been Published In Atmentioning

confidence: 76%

“…However, it is less well appreciated that they can also be found in the peripheral blood of patients with carcinoma and non-neoplastic disorders, and also healthy subjects. 14,15 They seem to be more common in patients with advanced malignancy than early stage malignancy and benign conditions. Megakaryocytes are commonly seen in pulmonary capillaries.…”

Section: Discussionmentioning

confidence: 99%

Cytology and cell‐block immunohistochemistry of circulating tumour cells

et al. 2019

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ObjectiveThe study set out to assess the feasibility of using ParsortixTM circulating tumour cell (CTC) extraction and CytoFoam Disc cell‐block immunohistochemistry to diagnose metastatic carcinoma from blood samples in a National Health Service district general hospital.MethodsBlood samples were taken from 50 patients with metastatic carcinoma and 50 healthy volunteers and processed, using a previously published method, to extract CTCs and collect them in a cell‐block for routine formalin‐fixed paraffin sectioning and immunohistochemistry. The extracted cells were compared with the patients’ routine diagnostic samples.ResultsThe samples from the 50 carcinoma patients showed cytokeratin‐positive cells in 19 cases. In eight of these, the cytokeratin‐positive cells had a similar immunoprofile to the carcinoma in the conventional biopsy or cytology specimen. Some carcinoma patients also had circulating cytokeratin‐positive cells that were probably benign epithelial cells and circulating megakaryocytes. Both of these types of cells were also found in healthy volunteers. Processing and initial examination could be completed in 2 days. The full processing cost was approximately £316 per case.ConclusionsCTCs could be extracted from the blood of some patients with metastatic carcinoma and formed into a formalin‐fixed cell‐block for routine paraffin processing and immunohistochemistry. The specificity of this approach is constrained by the observation that some patients with metastatic carcinoma had circulating cytokeratin‐positive cells that were probably benign, and these were also found in healthy volunteers. Circulating megakaryocytes were present in carcinoma patients and healthy volunteers.

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“…hour in humans. [13][14][15] Indeed, an abundance of MKs has long been employed clinically as confirmation that a vascular aspirate reflects the pulmonary capillary bed. 16 Trapped pulmonary MKs remain functional.…”

Section: Introductionmentioning

confidence: 99%

Megakaryocytes as immune cells

Cunin

Nigrović

2019

Journal of Leukocyte Biology

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Platelets play well‐recognized roles in inflammation, but their cell of origin—the megakaryocyte—is not typically considered an immune lineage. Megakaryocytes are large polyploid cells most commonly identified in bone marrow. Egress via sinusoids enables migration to the pulmonary capillary bed, where elaboration of platelets can continue. Beyond receptors involved in hemostasis and thrombosis, megakaryocytes express receptors that confer immune sensing capacity, including TLRs and Fc‐γ receptors. They control the proliferation of hematopoietic cells, facilitate neutrophil egress from marrow, possess the capacity to cross‐present antigen, and can promote systemic inflammation through microparticles rich in IL‐1. Megakaryocytes internalize other hematopoietic lineages, especially neutrophils, in an intriguing cell‐in‐cell interaction termed emperipolesis. Together, these observations implicate megakaryocytes as direct participants in inflammation and immunity.

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Megakaryocytes in the Pulmonary Circulation

Cited by 59 publications

References 11 publications

The aetiology of clubbing and hypertrophic osteoarthropathy

The aetiology of clubbing and hypertrophic osteoarthropathy

Cytology and cell‐block immunohistochemistry of circulating tumour cells

Megakaryocytes as immune cells

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