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Imaging leukocyte trafficking in vivo with two-photon-excited endogenous tryptophan fluorescence.

Li C, Pastila RK, Pitsillides C, Runnels JM, Puoris'haag M, Côté D, Lin CP - Opt Express (2010)

Bottom Line: We describe a new method for imaging leukocytes in vivo by exciting the endogenous protein fluorescence in the ultraviolet (UV) spectral region where tryptophan is the major fluorophore.Two-photon excitation near 590 nm allows noninvasive optical sectioning through the epidermal cell layers into the dermis of mouse skin, where leukocytes can be observed by video-rate microscopy to interact dynamically with the dermal vascular endothelium.Because the new method alleviates the need to introduce exogenous labels, it is potentially applicable for tracking leukocytes and monitoring inflammatory cellular reactions in humans.

View Article: PubMed Central - PubMed

Affiliation: Wellman Center for Photomedicine and Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA. Li.Chunqiang@mgh.harvard.edu

ABSTRACT
We describe a new method for imaging leukocytes in vivo by exciting the endogenous protein fluorescence in the ultraviolet (UV) spectral region where tryptophan is the major fluorophore. Two-photon excitation near 590 nm allows noninvasive optical sectioning through the epidermal cell layers into the dermis of mouse skin, where leukocytes can be observed by video-rate microscopy to interact dynamically with the dermal vascular endothelium. Inflammation significantly enhances leukocyte rolling, adhesion, and tissue infiltration. After exiting the vasculature, leukocytes continue to move actively in tissue as observed by time-lapse microscopy, and are distinguishable from resident autofluorescent cells that are not motile. Because the new method alleviates the need to introduce exogenous labels, it is potentially applicable for tracking leukocytes and monitoring inflammatory cellular reactions in humans.

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Related in: MedlinePlus

Single-frame excerpts from video recordings of leukocyte trafficking in skin vasculature. (a) Rolling leukocyte in normal BALB/c mouse skin (Media 1). (b) Slow rolling and arrest of leukocyte in inflamed skin (Media 2).
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g005: Single-frame excerpts from video recordings of leukocyte trafficking in skin vasculature. (a) Rolling leukocyte in normal BALB/c mouse skin (Media 1). (b) Slow rolling and arrest of leukocyte in inflamed skin (Media 2).

Mentions: In the normal skin, leukocytes constantly traffic to the skin at low levels as part of the immune surveillance mechanism. This trafficking process involves leukocyte tethering, rolling, arrest and transmigration through the endothelial walls into the tissue and is regulated by cytokines, and cell adhesion molecules (integrins and selectins) [25]. Whereas flowing leukocytes in the blood stream are moving too fast to image even with video-rate scanning, slow rolling cells can be observed interacting with the blood vessel walls (Media 1, and Fig. 5 (a)Fig. 5


Imaging leukocyte trafficking in vivo with two-photon-excited endogenous tryptophan fluorescence.

Li C, Pastila RK, Pitsillides C, Runnels JM, Puoris'haag M, Côté D, Lin CP - Opt Express (2010)

Single-frame excerpts from video recordings of leukocyte trafficking in skin vasculature. (a) Rolling leukocyte in normal BALB/c mouse skin (Media 1). (b) Slow rolling and arrest of leukocyte in inflamed skin (Media 2).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3369551&req=5

g005: Single-frame excerpts from video recordings of leukocyte trafficking in skin vasculature. (a) Rolling leukocyte in normal BALB/c mouse skin (Media 1). (b) Slow rolling and arrest of leukocyte in inflamed skin (Media 2).
Mentions: In the normal skin, leukocytes constantly traffic to the skin at low levels as part of the immune surveillance mechanism. This trafficking process involves leukocyte tethering, rolling, arrest and transmigration through the endothelial walls into the tissue and is regulated by cytokines, and cell adhesion molecules (integrins and selectins) [25]. Whereas flowing leukocytes in the blood stream are moving too fast to image even with video-rate scanning, slow rolling cells can be observed interacting with the blood vessel walls (Media 1, and Fig. 5 (a)Fig. 5

Bottom Line: We describe a new method for imaging leukocytes in vivo by exciting the endogenous protein fluorescence in the ultraviolet (UV) spectral region where tryptophan is the major fluorophore.Two-photon excitation near 590 nm allows noninvasive optical sectioning through the epidermal cell layers into the dermis of mouse skin, where leukocytes can be observed by video-rate microscopy to interact dynamically with the dermal vascular endothelium.Because the new method alleviates the need to introduce exogenous labels, it is potentially applicable for tracking leukocytes and monitoring inflammatory cellular reactions in humans.

View Article: PubMed Central - PubMed

Affiliation: Wellman Center for Photomedicine and Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA. Li.Chunqiang@mgh.harvard.edu

ABSTRACT
We describe a new method for imaging leukocytes in vivo by exciting the endogenous protein fluorescence in the ultraviolet (UV) spectral region where tryptophan is the major fluorophore. Two-photon excitation near 590 nm allows noninvasive optical sectioning through the epidermal cell layers into the dermis of mouse skin, where leukocytes can be observed by video-rate microscopy to interact dynamically with the dermal vascular endothelium. Inflammation significantly enhances leukocyte rolling, adhesion, and tissue infiltration. After exiting the vasculature, leukocytes continue to move actively in tissue as observed by time-lapse microscopy, and are distinguishable from resident autofluorescent cells that are not motile. Because the new method alleviates the need to introduce exogenous labels, it is potentially applicable for tracking leukocytes and monitoring inflammatory cellular reactions in humans.

Show MeSH
Related in: MedlinePlus