Endothelial glycocalyx thickness and platelet-vessel wall interactions during atherogenesis

2011 ◽  
Vol 106 (11) ◽  
pp. 939-946 ◽  
Author(s):  
Mirjam oude Egbrink ◽  
Viviane Heijnen ◽  
Remco Megens ◽  
Wim Engels ◽  
Hans Vink ◽  
...  
Keyword(s):  
Vessel Wall ◽  
Laser Scanning ◽  
Ex Vivo ◽  
Laser Scanning Microscopy ◽  
Endothelial Glycocalyx ◽  
Knock Out ◽  
Two Photon ◽  
Common Carotid Arteries ◽  
Wall Interactions

SummaryThe endothelial glycocalyx (EG), the luminal cover of endothelial cells, is considered to be atheroprotective. During atherogenesis, platelets adhere to the vessel wall, possibly triggered by simultaneous EG modulation. It was the objective of this study to investigate both EG thickness and platelet-vessel wall interactions during atherogenesis in the same experimental model. Intravital fluorescence microscopy was used to study platelet-vessel wall interactions in vivo in common carotid arteries and bifurcations of C57bl6/J (B6) and apolipoprotein E knock-out (ApoE-/-) mice (age 7 – 31 weeks). At the same locations, EG thickness was determined ex vivo using two-photon laser scanning microscopy. In ApoE-/- bifurcations the overall median level of adhesion was 48 platelets/mm2 (interquartile range: 16 – 80), which was significantly higher than in B6 bifurcations (0 (0 – 16), p = 0.001). This difference appeared to result from a significant age-dependent increase in ApoE-/- mice, while no such change was observed in B6 mice. At the same time, the EG in ApoE-/- bifurcations was significantly thinner than in B6 bifurcations (2.2 vs. 2.5 μm, respectively; p < 0.05). This resulted from the fact that in B6 bifurcations EG thickness increased with age (from 2.4 μm in young mice to 3.0 μm in aged ones), while in bifurcations of ApoE-/- mice this growth appeared to be absent (2.2 μm at all ages). During atherogenesis, platelet adhesion to the wall of the carotid artery bifurcation increases significantly. At the same location, EG growth with age is hampered. Therefore, glycocalyx-reinforcing strategies could possibly ameliorate atherosclerosis.

scholarly journals High-speed volumetric two-photon fluorescence imaging of neurovascular dynamics

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiang Lan Fan ◽  
Jose A. Rivera ◽  
Wei Sun ◽  
John Peterson ◽  
Henry Haeberle ◽  
...  
Keyword(s):  
Blood Flow ◽  
High Speed ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Microscopy ◽  
Fluorescence Signal ◽  
Imaging Method ◽  
Spatiotemporal Resolution ◽  
Two Photon

AbstractUnderstanding the structure and function of vasculature in the brain requires us to monitor distributed hemodynamics at high spatial and temporal resolution in three-dimensional (3D) volumes in vivo. Currently, a volumetric vasculature imaging method with sub-capillary spatial resolution and blood flow-resolving speed is lacking. Here, using two-photon laser scanning microscopy (TPLSM) with an axially extended Bessel focus, we capture volumetric hemodynamics in the awake mouse brain at a spatiotemporal resolution sufficient for measuring capillary size and blood flow. With Bessel TPLSM, the fluorescence signal of a vessel becomes proportional to its size, which enables convenient intensity-based analysis of vessel dilation and constriction dynamics in large volumes. We observe entrainment of vasodilation and vasoconstriction with pupil diameter and measure 3D blood flow at 99 volumes/second. Demonstrating high-throughput monitoring of hemodynamics in the awake brain, we expect Bessel TPLSM to make broad impacts on neurovasculature research.

scholarly journals Two-Photon Laser-Scanning Microscopy for Single and Repetitive Imaging of Dorsal and Lateral Spinal White Matter In Vivo

2017 ◽  
pp. 531-537 ◽  
Author(s):  
F. NADRIGNY ◽  
K. LE MEUR ◽  
E. D. SCHOMBURG ◽  
S. SAFAVI-ABBASI ◽  
P. DIBAJ
Keyword(s):  
White Matter ◽  
Laser Scanning ◽  
Dorsal Column ◽  
Minimal Invasive ◽  
Laser Scanning Microscopy ◽  
Intravenous Anesthesia ◽  
Two Photon ◽  
Simultaneous Imaging ◽  
Volatile Anesthesia

We developed appropriate surgical procedures for single and repetitive multi-photon imaging of spinal cord in vivo. By intravenous anesthesia, artificial ventilation and laminectomy, acute experiments were performed in the dorsal and lateral white matter. By volatile anesthesia and minimal-invasive surgery, chronic repetitive imaging up to 8 months was performed in the dorsal column through the window between two adjacent spines. Transgenic mouse technology enabled simultaneous imaging of labeled axons, astrocytes and microglia. Repetitive imaging showed positional shifts of microglia over time. These techniques serve for investigations of cellular dynamics and cell-cell interactions in intact and pathologically changed spinal tissue.

Apolipoprotein E Receptor 2′ Mediates Pathogenic Effects of Dimeric β2glycoprotein I and of Anti- β2glycoprotein I Antibodies in Vivo

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 408-408
Author(s):  
Zurina Romay-Penabad ◽  
Rolf T Urbanus ◽  
Elizabeth Pappalardo ◽  
Yong Hwang ◽  
Ronald H.W.M. Derksen ◽  
...  
Keyword(s):  
Apolipoprotein E ◽  
Laser Scanning ◽  
Carotid Arteries ◽  
Ex Vivo ◽  
Thrombus Formation ◽  
Peritoneal Macrophages ◽  
Laser Scanning Microscopy ◽  
Target Cells ◽  
Pathogenic Effects

Abstract Antiphospholipid antibodies (aPL) recognize β2Glycoprotein (β2GPI)-bound to receptor (s) in target cells and trigger a pro-coagulant/pro-inflammatory phenotype [i e.:expression of tissue factor (TF), vascular cell adhesion molecule-1 (VCAM-1)] that lead to thrombosis. The interaction of β2GPI with target cells may involve more than one protein. Investigators have shown that dimeric β2GPI binds to apolipoprotein E receptor 2′ (apoER2′) in platelets, in the absence of anti-β2GPI antibodies, increases their activation and induces enhanced thrombosis and TF activity in mice. However, the role of apoER2′ in vivo in Antiphospholipid Syndrome (APS) is not completely understood. Here, we examined the in vivo effects of dimeric β2GPI and of anti-β2GPI antibodies (IgG-APS) in apoER2′ deficient (−/−) mice and in normal mice pre-treated with recombinant soluble domain 1 of apoER2′ (BD1). In vivo, dynamics of thrombus formation (thrombus sizes), TF activities in carotid artery homogenates and in peritoneal macrophages and ex vivo expression of VCAM-1 in aortas and of TF activity in peritoneal macrophages were examined in the various types of mice after two i.p. injections with 40 μg of recombinant dimeric β2GPI – or with the corresponding monomer control – or with 500 μg IgG-APS (isolated from a patient with APS by protein G Sepharose) or with control IgG (IgG-NHS). Mice injected with IgG-APS had significant titers of anticardiolipin (aCL) and anti-β2GPI antibodies in their sera. In vivo, IgG-APS increased significantly the size of the induced thrombi as well as the TF activities in carotid arteries and in peritoneal macrophages in C57BL/6J (wild type) mice when compared to same type of mice treated with IgG-NHS. Similarly, ex vivo expression of VCAM-1 in mouse aortas and of TF in peritoneal macrophages, detected by two photon excitation laser scanning microscopy were increased in normal mice treated with IgG-APS when compared to control mice. The pre-treatment with 40 μg of BD1 i.p., significantly reduced those effects. Importantly, dimeric β2GPI (in the absence of anti-β2GPI antibodies) or IgGAPS did not increase significantly thrombus size, TF activities in homogenates of carotid arteries or in peritoneal macrophages, or ex vivo expression of VCAM-1 and TF in mice lacking apoER2′. Conclusions: Altogether these data show that dimers of β2GPI mimic pathogenic effects of anti-β2GPI antibodies in mice. Most importantly, apoER2′ is a mediator of those effects in vivo. These findings may provide insights not only for a better understanding of the pathophysiology of APS but may be important in the development of new targeted therapies, by means of interfering with the binding of β2GPI-aPL complexes with their receptor(s) in target cells in vivo.

scholarly journals Deflection of a vibrissa leads to a gradient of strain across mechanoreceptors in a mystacial follicle

2015 ◽  
Vol 114 (1) ◽  
pp. 138-145 ◽  
Author(s):  
Samuel J. Whiteley ◽  
Per M. Knutsen ◽  
David W. Matthews ◽  
David Kleinfeld
Keyword(s):  
Laser Scanning ◽  
Ex Vivo ◽  
Volumetric Strain ◽  
Laser Scanning Microscopy ◽  
Cell Nuclei ◽  
Two Photon ◽  
Before And After ◽  
Mechanical Transduction ◽  
Lower Magnitude ◽  
Active Exploration

Rodents use their vibrissae to detect and discriminate tactile features during active exploration. The site of mechanical transduction in the vibrissa sensorimotor system is the follicle sinus complex and its associated vibrissa. We study the mechanics within the ring sinus (RS) of the follicle in an ex vivo preparation of the mouse mystacial pad. The sinus region has a relatively dense representation of Merkel mechanoreceptors and longitudinal lanceolate endings. Two-photon laser-scanning microscopy was used to visualize labeled cell nuclei in an ∼100-nl vol before and after passive deflection of a vibrissa, which results in localized displacements of the mechanoreceptor cells, primarily in the radial and polar directions about the vibrissa. These displacements are used to compute the strain field across the follicle in response to the deflection. We observe compression in the lower region of the RS, whereas dilation, with lower magnitude, occurs in the upper region, with volumetric strain ΔV/V ∼ 0.01 for a 10° deflection. The extrapolated strain for a 0.1° deflection, the minimum angle that is reported to initiate a spike by primary neurons, corresponds to the minimum strain that activates Piezo2 mechanoreceptor channels.

scholarly journals SipA Activation of Caspase-3 Is a Decisive Mediator of Host Cell Survival at Early Stages of Salmonella enterica Serovar Typhimurium Infection

2017 ◽  
Vol 85 (9) ◽  
Author(s):  
Anne McIntosh ◽  
Lynsey M. Meikle ◽  
Michael J. Ormsby ◽  
Beth A. McCormick ◽  
John M. Christie ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Actin Polymerization ◽  
Caspase 3 ◽  
Ex Vivo ◽  
Cell Types ◽  
Laser Scanning Microscopy ◽  
Limiting Factor ◽  
Dual Function ◽  
Content Type

ABSTRACT Salmonella invasion protein A (SipA) is a dual-function effector protein that plays roles in both actin polymerization and caspase-3 activation in intestinal epithelial cells. To date its function in other cell types has remained largely unknown despite its expression in multiple cell types and its extracellular secretion during infection. Here we show that in macrophages SipA induces increased caspase-3 activation early in infection. This activation required a threshold level of SipA linked to multiplicity of infection and may be a limiting factor controlling bacterial numbers in infected macrophages. In polymorphonuclear leukocytes, SipA or other Salmonella pathogenicity island 1 effectors had no effect on induction of caspase-3 activation either alone or in the presence of whole bacteria. Tagging of SipA with the small fluorescent phiLOV tag, which can pass through the type three secretion system, allowed visualization and quantification of caspase-3 activation by SipA-phiLOV in macrophages. Additionally, SipA-phiLOV activation of caspase-3 could be tracked in the intestine through multiphoton laser scanning microscopy in an ex vivo intestinal model. This allowed visualization of areas where the intestinal epithelium had been compromised and demonstrated the potential use of this fluorescent tag for in vivo tracking of individual effectors.

scholarly journals Changes in Synaptic Terminal Structure in Adolescent Rat during Pregnancy; The Action Potential Propagation and Synaptic Transmission

2020 ◽  
pp. 1-8
Keyword(s):  
Synaptic Plasticity ◽  
Laser Scanning ◽  
Structural Changes ◽  
Specific Pattern ◽  
Laser Scanning Microscopy ◽  
Synaptic Activity ◽  
Two Photon ◽  
Sensory Experiences ◽  
Terminal Structure

Synaptic plasticity is a biological system of specific pattern of synaptic activity result in changes in synaptic strength. This influence puberty, pregnancy hormones, sensory experiences, and brain disorders. Long-term synaptic plasticity is accompanied by protein synthesis and trafficking, leading to structural changes of the synapse. Increasing evidence connects the terminal synaptic changes with potential propagation in adolescent and pregnancy. We investigate on the synaptic structural plasticity, which has mainly been studied with in vivo two photon laser scanning microscopy. We also discuss how a different type of synapses, the multicontact synapses associated with pregnancy.

scholarly journals CdSe/CdS-quantum rods: fluorescent probes for in vivo two-photon laser scanning microscopy

Nanoscale ◽  
2014 ◽  
Vol 6 (17) ◽  
pp. 10413-10422 ◽  
Author(s):  
Jelena Dimitrijevic ◽  
Lisa Krapf ◽  
Christopher Wolter ◽  
Christian Schmidtke ◽  
Jan-Philip Merkl ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Laser Scanning ◽  
Aqueous Media ◽  
Laser Scanning Microscopy ◽  
Scanning Microscopy ◽  
Cds Quantum Dots ◽  
Two Photon ◽  
Quantum Rods ◽  
And Performance

CdSe/CdS-Quantum-dots-quantum-rods are encapsulated by PI-b-PEG shells and transferred into various aqueous media to study their stability and performance as probes for two-photon laser scanning microscopy.

Sign in / Sign up

Export Citation Format

Share Document