Indocyanine green and lymphatic imaging: current problems.
BACKGROUND
Near-infrared (NIR) fluorescence imaging using indocyanine green (ICG) has recently been presented as a comparatively easy and informative technique to image lymphatic channels in vivo. However, no data or references have been provided concerning the impact of ICG application on normal lymphatic contractility and lymph transport. Thus, the imaging agent and/or the method of administration may introduce a significant artifact.


RESULTS
Standard pharmacological tests were performed to investigate the influence of ICG on the spontaneous contractility of isolated, cannulated, and pressurized rat mesenteric lymphatic vessels. The data demonstrate that non-irradiated ICG dramatically and dynamically influences the contractility of rat lymphatic vessels in both a dose- and diluent-dependent manner with low ICG concentrations principally altering contractile frequency and higher ICG concentrations completely blocking lymphatic contractility.


CONCLUSIONS
Currently, both researchers and doctors should exercise caution in extrapolating the data obtained with ICG imaging to normal lymphatic function regardless of whether it was obtained in mice, pigs, or humans. Careful and extended pharmacological tests must be performed to evaluate the mechanism of action of ICG on the contractility and physiology of lymphatic vessels with consideration of dose, diluent, and duration of irradiation.
Gashev
Anatoliy A
AA
Department of Systems Biology and Translational Medicine, College of Medicine, Cardiovascular Research Institute, Division of Lymphatic Biology, Texas A&M Health Science Center, Temple, Texas 76504, USA. gashev@tamu.edu
Nagai
Takashi
T
Bridenbaugh
Eric A
EA
D000818:Animals; D004396:Coloring Agents / Q000008:administration & dosage / Q000494:pharmacology; D003952:Diagnostic Imaging / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D004395:Dye Dilution Technique; D005453:Fluorescence; D007208:Indocyanine Green / Q000008:administration & dosage / Q000494:pharmacology; D008196:Lymph / Q000502:physiology; D042601:Lymphatic Vessels / Q000503:physiopathology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012015:Reference Standards
D004396:Coloring Agents; D007208:Indocyanine Green