scholarly journals Leukocyte recruitment in the airways: an intravital microscopic study of rat tracheal microcirculation

2002 ◽  
Vol 282 (5) ◽  
pp. L959-L967 ◽  
Author(s):  
Lina H. K. Lim ◽  
Bruce S. Bochner ◽  
Elizabeth M. Wagner
Keyword(s):  
Real Time ◽  
Leukocyte Recruitment ◽  
New Method ◽  
Histological Evaluation ◽  
Leukocyte Rolling ◽  
Adherent Cells ◽  
Rolling Velocity ◽  
Leukocyte Extravasation ◽  
Local Superfusion

Because of its relative inaccessibility, inflammatory cell extravasation within the airway circulation in vivo has been difficult to investigate in real time. A new method has been established using intravital microscopy in the anesthetized rat to visualize leukocytes in superficial postcapillary venules of the trachea. This technique has been validated using local superfusion of lipopolysaccharide (LPS) and N-formyl-methionyl-leucyl-phenylalanine (FMLP). Basal leukocyte rolling velocity (55.4 ± 9.3 μm/s) and adhesion (1.4 ± 0.3 cells/100 μm) were monitored in postcapillary venules (33.9 ± 1.3 μm diameter). At all time points up to 90 min, these parameters were unaltered in control rats ( n= 7). In contrast, vessels exposed to 1 μg/ml of LPS ( n = 6) exhibited a 57% reduction in leukocyte rolling velocity and an increase in the number of adherent cells (4.7 ± 1 cells/100 μm, P < 0.05). Superfusion with 0.1 μM of FMLP ( n = 6) also resulted in a 45% reduction in rolling velocity and an increase in adherent cells (4 ± 0.7 cells/100 μm, P < 0.05). Histological evaluation confirmed local stimulus-induced leukocyte extravasation. These results demonstrate leukocyte recruitment in the airway microvasculature and provide an important new method to study airway inflammation in real time.

Leukocyte PI3Kγ and PI3Kδ have temporally distinct roles for leukocyte recruitment in vivo

Blood ◽  
2007 ◽  
Vol 110 (4) ◽  
pp. 1191-1198 ◽  
Author(s):  
Lixin Liu ◽  
Kamal D. Puri ◽  
Josef M. Penninger ◽  
Paul Kubes
Keyword(s):  
Early Response ◽  
Leukocyte Recruitment ◽  
Leukocyte Rolling ◽  
Bone Marrow Transplants ◽  
Functional Responses ◽  
Chemokine Production ◽  
Rolling Velocity ◽  
Parenchymal Cells ◽  
Class Ib

Abstract Phosphoinositide 3-kinases (PI3Ks) have been considered important in leukocyte motility. PI3Kγ, the class IB PI3K, expressed prominently in leukocytes and also in endothelial cells, mediates leukocyte functional responses induced by chemoattractants. To reveal its role in leukocyte recruitment, we used intravital microscopy to directly visualize leukocyte rolling, adhesion, and emigration in postcapillary venules in PI3Kγ-deficient (PI3Kγ-/-) mice. We report here that PI3Kγ deficiency had no significant effects on leukocyte rolling flux or rolling velocity and minor effects on adhesion (30% to 35%) in response to CXC chemokine MIP-2 (CXCL2) or KC (CXCL1). However, leukocyte emigration was severely impaired in PI3Kγ-/- mice in an early (first 90 minutes) response to MIP-2 or KC. Chimeric mice receiving bone marrow transplants revealed that this early response was entirely dependent upon PI3Kγ in neutrophils but not parenchymal cells (endothelium and others). Identical responses were observed when endogenous chemokine production was induced by TNFα; leukocyte emigration was reduced in PI3Kγ-/- mice. More prolonged responses to MIP-2 (for 4 to 5 hours) or TNFα (6 to 8 hours) were almost entirely PI3Kγ independent and largely dependent on PI3Kδ. Our results reveal that leukocyte emigration response to CXC chemokines is entirely dependent upon PI3Kγ or PI3Kδ, but these are nonoverlapping, temporally distinct events in inflamed tissues in vivo.

scholarly journals Sialyl Lewisx (sLex) and an sLexMimetic, CGP69669A, Disrupt E-Selectin–Dependent Leukocyte Rolling In Vivo

Blood ◽  
1998 ◽  
Vol 91 (2) ◽  
pp. 475-483 ◽  
Author(s):  
Keith E. Norman ◽  
Gary P. Anderson ◽  
Hartmut C. Kolb ◽  
Klaus Ley ◽  
Beat Ernst
Keyword(s):  
Leukocyte Rolling ◽  
Sialyl Lewisx ◽  
Necrosis Factor Alpha ◽  
Rolling Velocity ◽  
Beneficial Effects ◽  
Selectin Family ◽  
Factor Alpha ◽  
Observable Event

Abstract Leukocyte rolling is the earliest observable event in their recruitment from the circulation to inflamed tissue. This rolling is mediated largely by interaction between the selectin family of adhesion molecules and their glycosylated ligands. Although the nature of these ligands and their interaction with the selectins is not fully understood, it is accepted that expression of fucosylated sialylated glycans such as sialyl Lewisx (sLex) is required for function. Despite findings that sLex inhibits binding of leukocytes to E-selectin in vitro, and has beneficial effects in inflammatory disease models, inhibition of E-selectin–dependent leukocyte rolling in vivo has not been described. Functional overlap between the selectins has been noted and reduction of rolling by E-selectin antibodies only occurs if P-selectin is absent or blocked. We demonstrate that leukocyte rolling velocity in tumor necrosis factor alpha (TNFα)-stimulated mouse cremaster is increased following treatment with either sLex or the sLex-mimetic CGP69669A and that rolling is dramatically reduced if CGP69669A is applied in the presence of anti–P-selectin antibody. These effects are characteristic of E-selectin antagonism. In contrast, surgically stimulated (L- or P-selectin–dependent) rolling is unaffected by either sLex or CGP69669A. Our data demonstrate that CGP69669A is an effective and selective antagonist of E-selectin in vivo.

Spontaneous leukocyte rolling in venules in untraumatized skin of conscious and anesthetized animals

1994 ◽  
Vol 267 (3) ◽  
pp. H1199-H1204 ◽  
Author(s):  
G. H. Janssen ◽  
G. J. Tangelder ◽  
M. G. Oude Egbrink ◽  
R. S. Reneman
Keyword(s):  
Defense Mechanisms ◽  
Fluorescent Labeling ◽  
Leukocyte Rolling ◽  
Rolling Velocity ◽  
Conscious Rats ◽  
Swiss Mice ◽  
Anesthetized Rats ◽  
Mouse Ear ◽  
Rats And Mice

Intravital bright-field videomicroscopy was used to investigate whether leukocyte rolling can be observed under normal physiological conditions. We studied skin venules in trained conscious rats and anesthetized rats and mice without touching the skin itself. Leukocyte rolling was spontaneously present in all hindpaw venules of Lewis rats (diam 8-27 microns) and also in all mouse ear venules (Swiss, 13-38 microns; BALB/c, 12-56 microns). Rolling levels (in leukocytes/min, median and range) were 8 (3-15) in conscious rats, 9 (3-19) in anesthetized rats, 30 (5-160) in anesthetized Swiss mice, and 10 (3-22) in anesthetized BALB/c mice. These levels appeared to be independent of time. Noninvasive mechanical stimulation induced an average increase of 32%. Fluorescent labeling of leukocytes in vivo with acridine orange had no influence. In Swiss mice, the rolling velocity was < 50 microns/s for > 75% of the leukocytes (median 31 microns/s); this parameter did not correlate with reduced velocity (17-68 s-1) and hence wall shear rate. Our finding that leukocyte rolling is spontaneously present in skin venules of anesthetized and conscious animals suggests a constant vigilance of the host defense mechanisms in the skin.

Molecular mechanisms involved in superoxide-induced leukocyte-endothelial cell interactions in vivo

1994 ◽  
Vol 266 (2) ◽  
pp. H637-H642 ◽  
Author(s):  
J. P. Gaboury ◽  
D. C. Anderson ◽  
P. Kubes
Keyword(s):  
Molecular Mechanisms ◽  
Leukocyte Adhesion ◽  
Platelet Activating Factor ◽  
Leukocyte Rolling ◽  
Rolling Velocity ◽  
Paf Receptor ◽  
Rolling Leukocytes ◽  
Adherent Leukocytes ◽  
Web 2086

Intravital microscopy was used to monitor leukocyte adherence, flux, rolling velocity, and number of rolling leukocytes (flux/velocity) in venules 25–40 microns in diameter. The superoxide-generating system, hypoxanthine and xanthine oxidase (HX/XO), was infused into the mesenteric circulation in untreated animals or in animals pretreated with either catalase (a hydrogen peroxide scavenger), WEB-2086 [a platelet-activating factor (PAF) receptor antagonist], or monoclonal antibodies directed against adhesion molecules CD18 (CL26) or P-selectin (PB1.3). HX/XO infusion caused a decrease in leukocyte rolling velocity and an increase in the number of rolling and adherent leukocytes. WEB-2086 prevented the increase in leukocyte adhesion and markedly increased leukocyte rolling velocity. PB1.3 abolished the HX/XO-associated rise in the flux of rolling leukocytes and proportionally decreased the number of adherent leukocytes. CL26 abolished HX/XO-induced leukocyte adhesion and also reduced the number of rolling leukocytes. In conclusion, P-selectin mediates the increased leukocyte flux induced by superoxide, whereas PAF and CD18 modulate leukocyte adhesion. PAF also reduces leukocyte rolling velocity, possibly as a result of CD18, but not P-selectin.

Adenosine inhibits ischemia-reperfusion-induced leukocyte adherence and extravasation

1989 ◽  
Vol 257 (5) ◽  
pp. H1334-H1339 ◽  
Author(s):  
M. B. Grisham ◽  
L. A. Hernandez ◽  
D. N. Granger
Keyword(s):  
Small Intestine ◽  
Ischemia Reperfusion ◽  
H2o2 Production ◽  
Leukocyte Adherence ◽  
Rolling Velocity ◽  
Microvascular Injury ◽  
Leukocyte Extravasation ◽  
Anti Inflammatory ◽  
Venular Endothelium

Ischemia and reperfusion (I/R) of the small intestine initiates a series of events that result in neutrophil-mediated microvascular injury. Recent reports suggest that adenosine possesses anti-inflammatory properties by virtue of its ability to inhibit neutrophil (PMN) superoxide (O2-.) and hydrogen peroxide (H2O2) production and to interfere with PMN adherence to cultured endothelium. In an attempt to further characterize the anti-inflammatory properties of adenosine in vivo we assessed the influence of exogenous adenosine on 1) I/R-induced PMN-mediated microvascular injury in the feline small intestine, 2) feline PMN superoxide production, and 3) I/R-induced PMN adherence to feline mesenteric venular endothelium. We found that intra-arterial administration of adenosine (2 microM) significantly attenuated the I/R-induced increases in intestinal capillary permeability. This protective effect of adenosine could not be explained entirely on its ability to inhibit PMN O2-. (or H2O2) production, since adenosine was effective in inhibiting feline PMN O2-. production by only 20%. Using intravital microscopic techniques in cat mesentery, we found that adenosine did not alter the responses of venular blood flow, shear rate, leukocyte rolling velocity, and leukocyte adherence to I/R when compared with control animals. However, the number of extravasated leukocytes during the ischemic period was significantly reduced by adenosine. Adenosine reduced the number of adherent leukocytes by 25% at 10 and 60 min of reperfusion while leukocyte extravasation was reduced by 65-70% during the same period. Our data indicate that the adenosine-induced suppression of leukocyte extravasation cannot be explained solely by an attenuation in leukocyte adherence to venular endothelium.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunoblockade of PSGL-1 attenuates established experimental murine colitis by reduction of leukocyte rolling

2004 ◽  
Vol 287 (1) ◽  
pp. G115-G124 ◽  
Author(s):  
Emile M. Rijcken ◽  
Mike G. Laukoetter ◽  
Christoph Anthoni ◽  
Stephanie Meier ◽  
Rudolf Mennigen ◽  
...  
Keyword(s):  
Intestinal Inflammation ◽  
Activity Index ◽  
Leukocyte Adhesion ◽  
Combined Treatment ◽  
Disease Activity Index ◽  
Leukocyte Recruitment ◽  
Leukocyte Rolling ◽  
Chronic Colitis ◽  
Adhesive Interactions

Recruitment of circulating leukocytes into the colonic tissue is a key feature of intestinal inflammation. P-selectin glycoprotein ligand-1 (PSGL-1) and very late antigen-4 (VLA-4) are expressed on leukocytes and play an important role in leukocyte-endothelial cell adhesive interactions. We examined the effects of immunoneutralization of PSGL-1 and VLA-4 on leukocyte recruitment in vivo in the development and treatment of experimental colitis. Chronic colitis was induced in balb/c mice by oral administration of dextran sodium sulfate (DSS). Monoclonal antibodies 2PH1 (anti-PSGL-1) and PS/2 (anti-VLA-4) or the combination of both were injected intravenously, and leukocyte adhesion was observed for 60 min in colonic submucosal venules by intravital microscopy (IVM) under isoflurane/N2O anesthesia. In addition, mice with established colitis were treated by daily intraperitoneal injections of 2PH1, PS/2, or the combination of both over 5 days. Disease activity index (DAI), histology, and myeloperoxidase (MPO) levels were compared with sham-treated DSS controls. We found that 2PH1 reduced the number of rolling leukocytes (148.7 ± 29.8 vs. 36.9 ± 8.7/0.01 mm2/30 s, P < 0.05), whereas leukocyte velocity was increased (24.0 ± 3.6 vs. 127.8 ± 11.7 μm/s, P < 0.05). PS/2 reduced leukocyte rolling to a lesser extent. Leukocyte firm adhesion was not influenced by 2PH1 but was strongly reduced by PS/2 (24.1 ± 2 vs. 4.4 ± 0.9/0.01 mm2/30 s, P < 0.05). Combined application did not cause additional effects on leukocyte adhesion. Treatment of chronic colitis with 2PH1 or PS/2 reduced DAI, mucosal injury, and MPO levels significantly. Combined treatment led to a significantly better reduction of DAI (0.4 ± 0.1 vs. 2.1 ± 0.2 points) and histology (9.7 ± 0.9 vs. 21.4 ± 4.6 points). In conclusion, PSGL-1 and VLA-4 play an important role for leukocyte recruitment during intestinal inflammation. Therapeutic strategies designed to disrupt interactions mediated by PSGL-1 and/or VLA-4 may prove beneficial in treatment of chronic colitis.

scholarly journals P-selectin mediates spontaneous leukocyte rolling in vivo

Blood ◽  
1993 ◽  
Vol 82 (4) ◽  
pp. 1308-1316 ◽  
Author(s):  
M Dore ◽  
RJ Korthuis ◽  
DN Granger ◽  
ML Entman ◽  
CW Smith
Keyword(s):  
Intravital Microscopy ◽  
Initial Step ◽  
Enzyme Linked Immunosorbent Assay ◽  
Leukocyte Rolling ◽  
Rolling Velocity ◽  
Inhibition Control ◽  
First Time ◽  
Rolling Leukocytes

Rolling represents the initial step leading to leukocyte extravasation from blood vessels during an inflammatory reaction. In vitro studies indicate that P-selectin could be one of the ligands on endothelium involved in the rolling phenomenon, although the molecular determinants responsible for this transient attachment in vivo are still undefined. Our objectives were to develop a blocking monoclonal antibody against canine P-selectin and to use it to investigate the role of P-selectin in leukocyte rolling in vivo using the technique of intravital microscopy. P-selectin was immunoaffinity purified from canine platelets and used for the production of monoclonal antibodies. One of the hybridomas generated, MD6, was shown by enzyme-linked immunosorbent assay and by flow cytometry to bind preferentially to stimulated platelets and to completely prevent binding of stimulated platelets to neutrophils. Visualization of canine mesenteric venules by intravital microscopy showed that administration of MD6 resulted in a marked inhibition in the number of rolling leukocytes (18.96 +/- 9.92 v 156.40 +/- 19.50 leukocytes/min, P < .05; 88.3% +/- 6.0% inhibition). Control antibody MD3 (which recognizes a nonfunctional epitope of canine P- selectin) had no effect on the number of rolling leukocytes or on their rolling velocity. These results show for the first time that P-selectin plays an essential role in leukocyte rolling in vivo, and therefore may be a key participant of the inflammatory response.

scholarly journals A new method for the in vivo identification of degenerated material property ranges of the human eye: feasibility analysis based on synthetic data

2021 ◽  
Author(s):  
Stefan Muench ◽  
Mike Roellig ◽  
Daniel Balzani
Keyword(s):  
Real Time ◽  
Test Data ◽  
Synthetic Data ◽  
New Method ◽  
Data Sets ◽  
New Approach ◽  
Full Field ◽  
Material Parameters ◽  
Virtual Test

AbstractThis paper proposes a new method for in vivo and almost real-time identification of biomechanical properties of the human cornea based on non-contact tonometer data. Further goal is to demonstrate the method’s functionality based on synthetic data serving as reference. For this purpose, a finite element model of the human eye is constructed to synthetically generate full-field displacements from different data sets with keratoconus-like degradations. Then, a new approach based on the equilibrium gap method combined with a mechanical morphing approach is proposed and used to identify the material parameters from virtual test data sets. In a further step, random absolute noise is added to the virtual test data to investigate the sensitivity of the new approach to noise. As a result, the proposed method shows a relevant accuracy in identifying material parameters based on full-field displacements. At the same time, the method turns out to work almost in real time (order of a few minutes on a regular workstation) and is thus much faster than inverse problems solved by typical forward approaches. On the other hand, the method shows a noticeable sensitivity to rather small noise amplitudes rendering the method not accurate enough for the precise identification of individual parameter values. However, analysis show that the accuracy is sufficient for the identification of property ranges which might be related to diseased tissues. Thereby, the proposed approach turns out promising with view to diagnostic purposes.

scholarly journals Relevance of L-selectin Shedding for Leukocyte Rolling In Vivo

1999 ◽  
Vol 189 (6) ◽  
pp. 939-948 ◽  
Author(s):  
Ali Hafezi-Moghadam ◽  
Klaus Ley
Keyword(s):  
Leukocyte Rolling ◽  
Rolling Velocity ◽  
Tnf Α ◽  
Novel Method ◽  
Metalloprotease Inhibitor ◽  
Rolling Leukocytes ◽  
Deficient Mice ◽  
Necrosis Factor

The velocity of rolling leukocytes is thought to be determined by the expression of adhesion molecules and the prevailing wall shear stress. Here, we investigate whether rapid cleavage of L-selectin may be an additional physiologic regulatory parameter of leukocyte rolling. A unique protease in the membrane of leukocytes cleaves L-selectin after activation, resulting in L-selectin shedding. The hydroxamic acid–based metalloprotease inhibitor KD-IX-73-4 completely prevented L-selectin shedding in vitro and significantly decreased the rolling velocity of leukocytes in untreated wild-type C57BL/6 mice from 55 to 35 μm/s in vivo. When E-selectin was expressed on the endothelium (tumor necrosis factor [TNF]-α treatment 2.5–3 h before the experiment), rolling velocity was 4 μm/s and did not change after the application of KD-IX-73-4. However, KD-IX-73-4 decreased mean rolling velocity by 29% from 23 to 16 μm/s in E-selectin–deficient mice treated with TNF-α. The reduction of velocity caused by KD-IX-73-4 was immediate (&lt;5 s) after injection of KD-IX-73-4 as shown by a novel method using a local catheter. These results establish a role for L-selectin shedding in regulating leukocyte rolling velocity in vivo.

Mechanisms of decreased leukocyte localization in the developing host

2002 ◽  
Vol 282 (2) ◽  
pp. H636-H644 ◽  
Author(s):  
M. Michele Mariscalco ◽  
Wilfredo Vergara ◽  
Jia Mei ◽  
E. O'Brian Smith ◽  
C. Wayne Smith
Keyword(s):  
Host Defense ◽  
Intravital Microscopy ◽  
Leukocyte Recruitment ◽  
Surgical Trauma ◽  
Leukocyte Rolling ◽  
Primary Defect ◽  
Developmental Models ◽  
Rolling Velocity ◽  
Mesenteric Vessels ◽  
Adult Cells

Delays in leukocyte localization likely contribute to diminished host defense in neonates. Understanding the processes that may be affected has been hampered by the lack of suitable developmental models. Using intravital microscopy, we directly examine leukocyte recruitment in a rabbit pup model. In response to intraperitoneal interleukin (IL)-1β, there were one-third as many leukocytes that arrested in pup mesenteric vessels and emigrated compared with adult vessels, although leukocyte flux was not different. Leukocyte rolling velocity in pups was one-half that in adults. In response to surgical trauma alone, the number of arrested pup cells was 15% that of adult cells, although again leukocyte flux was not different. An anti-L-selectin antibody inhibited rolling significantly by 60 min for both pups and adults. The effect on arrest and emigration occurred at significantly earlier times, although the effect was less in rabbit pups. A primary defect in leukocyte emigration in the rabbit pup appears to be a failure of the cell to transition efficiently from rolling to arrest. L-selectin-dependent adhesion and emigration are decreased, rolling is not, suggesting that at least part of the defect is due to events downstream of the initial tether.

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