title: Dynamic contrast enhanced optical imaging of capillary leakage.
abstract: We studied in vivo the vascular permeability of two fluorescent contrast agents in three types of capillary, using a fibered confocal fluorescence microscopy system. Mice were imaged after injection of a macromolecular (albumin FITC 68,000 daltons) or low-molecular-weight contrast agent (FITC 389 daltons). We studied continuous capillaries in muscles (FITC n = 4, albumin FITC n = 6), fenestrated capillaries in mesenteries (FITC n = 8, albumin FITC n = 10), and discontinuous capillaries in xenografted tumors (FITC n = 2, albumin FITC n = 4). Signal intensity (SI) was measured in capillary and interstitial regions, and time-enhancement curves were drawn. Two-compartment models were constructed to determine quantitative microcirculation parameters. The arrival of the bolus of the two different contrast agents was observed in mesentery and muscle capillaries but not in tumor capillaries. Interstitial leakage of the low-molecular-weight contrast agent was observed almost instantaneously, whereas the macromolecular agent remained within the vessels. Signal intensity declined over the observation period, specifically in the tumor. No quantitative microcirculation parameters could be obtained with either of two bi compartmental models, owing to model instability. This study shows that the microcirculation can be reproducibly observed in different types of capillary in vivo with this fibered fluorescence imaging device. Further work is required to quantify microvascular parameters.
authors.affiliation: Laboratory Research Imaging, Paris Cardiovascular Research Center, Inserm U970 56 rue Leblanc, 75015 Paris, France. nath.faye@hotmail.fr
authors.forename: N
authors.initials: N
authors.lastname: Faye
authors.forename: L
authors.initials: L
authors.lastname: Fournier
authors.forename: D
authors.initials: D
authors.lastname: Balvay
authors.forename: F
authors.initials: F
authors.lastname: Taillieu
authors.forename: C
authors.initials: C
authors.lastname: Cuenod
authors.forename: N
authors.initials: N
authors.lastname: Siauve
authors.forename: O
authors.initials: O
authors.lastname: Clement
mesh_terms: D000818:Animals; D002196:Capillaries / Q000502:physiology*; D002199:Capillary Permeability; D003287:Contrast Media; D005336:Fiber Optic Technology; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives; D005456:Fluorescent Dyes; D051379:Mice; D008833:Microcirculation; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008970:Molecular Weight; D009132:Muscles / Q000098:blood supply*; D009369:Neoplasms / Q000098:blood supply*; D019047:Phantoms, Imaging; D012709:Serum Albumin; D013152:Splanchnic Circulation
chemical_list: D003287:Contrast Media; C518288:FITC-albumin; D005456:Fluorescent Dyes; D012709:Serum Albumin; D016650:Fluorescein-5-isothiocyanate