Neutrophil transit time and localization within the megakaryocyte define morphologically distinct forms of emperipolesis

Neutrophils transit through megakaryocytes in a process termed emperipolesis, but it is unknown whether this interaction is a single type of cell-in-cell interaction or a set of distinct processes. Using a murine in vitro model, we characterized emperipolesis by live-cell spinning disk microscopy and electron microscopy. Approximately half of neutrophils exited the megakaryocyte rapidly, typically in 10 minutes or less, displaying ameboid morphology as they passed through the host cell (fast emperipolesis). The remaining neutrophils assumed a sessile morphology, most remaining within the megakaryocyte for at least 60 minutes (slow emperipolesis). These neutrophils typically localized near the megakaryocyte nucleus. By ultrastructural assessment, all internalized neutrophils remained morphologically intact. Most neutrophils resided within emperisomes, but some could be visualized exiting the emperisome to enter the cell cytoplasm. Neutrophils in the cytoplasm assumed close contact with the platelet-forming demarcation membrane system or the perinuclear endoplasmic reticulum. These findings reveal that megakaryocyte emperipolesis reflects at least two distinct processes differing in transit time and morphology, fast and slow emperipolesis, suggesting divergent physiologic functions.

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Neutrophil transit time and localization within the megakaryocyte define morphologically distinct forms of emperipolesis

10.1101/2021.04.26.441404 ◽

2021 ◽

Author(s):

Frank Y. Huang ◽

Pierre Cunin ◽

Felix A. Radtke ◽

Ricardo Grieshaber-Bouyer ◽

Peter A. Nigrovic

Keyword(s):

Endoplasmic Reticulum ◽

Transit Time ◽

Close Contact ◽

Intracellular Localization ◽

Membrane System ◽

Cell Interaction ◽

Single Type ◽

List Type ◽

Cell Cytoplasm

AbstractIn emperipolesis, neutrophils transit through megakaryocytes, but it is unknown whether this interaction represents a single type of cell-in-cell interaction or a set of distinct processes. Using an in vitro model of murine emperipolesis, we characterized neutrophils entering megakaryocytes using live-cell spinning disk microscopy and electron microscopy. Approximately half of neutrophils exited the megakaryocyte rapidly, typically in 10 minutes or less, displaying ameboid morphology as they passed through the host cell (fast emperipolesis). The remaining neutrophils assumed a sessile morphology, most remaining within the megakaryocyte for at least 60 minutes (slow emperipolesis). These neutrophils typically localized near the megakaryocyte nucleus. By ultrastructural assessment, all internalized neutrophils remained morphologically intact. Most neutrophils resided within emperisomes, but some could be visualized exiting the emperisome into the cell cytoplasm. Neutrophils in the cytoplasm assumed close contact with the platelet-forming demarcation membrane system or with the perinuclear endoplasmic reticulum, as confirmed by immunofluorescence microscopy. Together, these findings reveal that megakaryocyte emperipolesis reflects at least two processes, fast and slow emperipolesis, each with its own characteristic transit time, morphology, and intracellular localization, suggesting distinct functions.Key PointsNeutrophil passage through megakaryocytes, termed emperipolesis, diverges into fast and slow forms that differ in transit time, morphology, and intracellular localizationDuring emperipolesis, neutrophils can reside in vacuoles (emperisomes) or escape into the cell cytoplasm to assume positions near the megakaryocyte’s demarcation membrane system, endoplasmic reticulum, or nucleus.

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The Swallowing Characteristics of Thickeners, Jellies and Yoghurt Observed Using an In Vitro Model

Dysphagia ◽

10.1007/s00455-019-10074-1 ◽

2019 ◽

Vol 35 (4) ◽

pp. 685-695 ◽

Cited By ~ 1

Author(s):

Simmi Patel ◽

William J. McAuley ◽

Michael T. Cook ◽

Yi Sun ◽

Shaheen Hamdy ◽

...

Keyword(s):

Transit Time ◽

Mechanical Model ◽

Xanthan Gum ◽

In Vitro Model ◽

High Concentration ◽

High Concentrations ◽

Vitro Model ◽

Thickening Agents

Abstract Drinks and foods may be thickened to improve swallowing safety for dysphagia patients, but the resultant consistencies are not always palatable. Characterising alternative appetising foods is an important task. The study aims to characterise the in vitro swallowing behaviour of specifically formulated thickened dysphagia fluids containing xanthan gum and/or starch with standard jellies and yoghurt using a validated mechanical model, the “Cambridge Throat”. Observing from the side, the model throat can follow an experimental oral transit time (in vitro-OTT) and a bolus length (BL) at the juncture of the pharynx and larynx, to assess the velocity and cohesion of bolus flow. Our results showed that higher thickener concentration produced longer in vitro-OTT and shorter BL. At high concentration (spoon-thick), fluids thickened with starch-based thickener showed significantly longer in vitro-OTT than when xanthan gum-based thickener was used (84.5 s ± 34.5 s and 5.5 s ± 1.6 s, respectively, p < 0.05). In contrast, at low concentration (nectar-like), fluids containing xanthan gum-based thickener demonstrated shorter BL than those of starch-based thickener (6.4 mm ± 0.5 mm and 8.2 mm ± 0.8 mm, respectively, p < 0.05). The jellies and yoghurt had comparable in vitro-OTT and BL to thickeners at high concentrations (honey-like and spoon-thick), indicating similar swallowing characteristics. The in vitro results showed correlation with published in vivo data though the limitations of applying the in vitro swallowing test for dysphagia studies were noted. These findings contribute useful information for designing new thickening agents and selecting alternative and palatable safe-to-swallow foods.

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An in vitro model of biomaterial-augmented microfracture including chondrocyte–progenitor cell interaction

Archives of Orthopaedic and Trauma Surgery ◽

10.1007/s00402-010-1079-2 ◽

2010 ◽

Vol 130 (5) ◽

pp. 711-716 ◽

Cited By ~ 4

Author(s):

Patrick Vavken ◽

Ferdi Arrich ◽

Magdalena Pilz ◽

Ronald Dorotka

Keyword(s):

Progenitor Cell ◽

In Vitro Model ◽

Cell Interaction ◽

Vitro Model

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A novel in vitro model for the study of plaque development in atherosclerosis

Thrombosis and Haemostasis ◽

10.1160/th05-05-0357 ◽

2006 ◽

Vol 95 (01) ◽

pp. 182-189 ◽

Cited By ~ 19

Author(s):

Michael Torzewski ◽

Manfred Dahm ◽

Viola Ochsenhirt ◽

Hans-Anton Lehr ◽

Karl Lackner ◽

...

Keyword(s):

In Vitro Model ◽

Foam Cell ◽

Close Contact ◽

Cell Formation ◽

Brdu Incorporation ◽

Foam Cell Formation ◽

Fibrin Gel ◽

Plaque Development ◽

Vitro Model

SummaryFor the study of atherogenesis in vitro, coculture systems have been devised, in which two or more cell types can be cultured in close contact to each other. Herein, we describe a novel in vitro model that aims at the simulation of the morphology ofa normal muscular artery allowing for the study of the initial events in atherosclerosis. Usinga modified fibrin gel as a scaffold for the coculture of endothelial cells (ECs) and smooth muscle cells (SMCs), we generated an autologous in vitro model with a multilayer growth of SMCs (intima-like structure) covered by an endothelium. The production of extracellular matrix (ECM) could be visualized histologically and verified by (i) ascorbic-acid dependent secretion of procollagenI into the supernatant and (ii) deposition of collagens I and III as well as laminin in the gel as assessed by immunohistochemistry. By BrdU-incorporation and Ki67 expression, the SMCs exhibited minimal proliferative activity, even when the culture period was extended to6 weeks. Lipoprotein insudation was investigated under simulated hypo-, normo-and hypercholesterolemic conditions through addition of 0.5, 1 or2 mg/mL LDL to the medium with subsequent time and dose dependend insudation of LDL. When human monocytes were added to the culture medium, infiltration and foam cell formation of macrophages and SMCs as well as expression of interleukin-8 (IL-8) was demonstrated. The in vitro model of the human vascular wall described herein appears to be suitable for the study of pivotal events in atherosclerotic plaque development. The applicability for long-term culture, the ability to study cell-matrix interactions and the opportunities for histomorphological and immunohistochemical examinations represent additional advantages of this model.

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An in vitro model for investigation of vitamin A effects on wound healing

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000692 ◽

2021 ◽

pp. 1-6

Author(s):

Hoda Keshmiri Neghab ◽

Mohammad Hasan Soheilifar ◽

Gholamreza Esmaeeli Djavid

Keyword(s):

Wound Healing ◽

Endothelial Cell ◽

Vitamin A ◽

In Vitro Model ◽

Cellular Proliferation ◽

Endothelial Cell Migration ◽

Normal Fibroblast ◽

Anti Inflammatory ◽

Vitro Model

Abstract. Wound healing consists of a series of highly orderly overlapping processes characterized by hemostasis, inflammation, proliferation, and remodeling. Prolongation or interruption in each phase can lead to delayed wound healing or a non-healing chronic wound. Vitamin A is a crucial nutrient that is most beneficial for the health of the skin. The present study was undertaken to determine the effect of vitamin A on regeneration, angiogenesis, and inflammation characteristics in an in vitro model system during wound healing. For this purpose, mouse skin normal fibroblast (L929), human umbilical vein endothelial cell (HUVEC), and monocyte/macrophage-like cell line (RAW 264.7) were considered to evaluate proliferation, angiogenesis, and anti-inﬂammatory responses, respectively. Vitamin A (0.1–5 μM) increased cellular proliferation of L929 and HUVEC (p < 0.05). Similarly, it stimulated angiogenesis by promoting endothelial cell migration up to approximately 4 fold and interestingly tube formation up to 8.5 fold (p < 0.01). Furthermore, vitamin A treatment was shown to decrease the level of nitric oxide production in a dose-dependent effect (p < 0.05), exhibiting the anti-inflammatory property of vitamin A in accelerating wound healing. These results may reveal the therapeutic potential of vitamin A in diabetic wound healing by stimulating regeneration, angiogenesis, and anti-inﬂammation responses.

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