Current clinical methods for the evaluation of lymphatic vessel function, crucial for early diagnosis and evaluation of treatment response of several pathological conditions, in particular of postsurgical lymphedema, are based on complex and mainly qualitative imaging techniques. To address this unmet medical need, we established a simple strategy for the painless and quantitative assessment of cutaneous lymphatic function. We prepared a lymphatic-specific tracer formulation, consisting of the clinically approved near-infrared fluorescent dye, indocyanine green, and the solubilizing surfactant Kolliphor HS15. The tracer was noninvasively delivered to the dermal layer of the skin using MicronJet600 hollow microneedles, and the fluorescence signal decay at the injection site was measured over time using a custom-made, portable detection device. The decay rate of fluorescence signal in the skin was used as a direct measure of lymphatic vessel drainage function. With this method, we could quantify impaired lymphatic clearance in transgenic mice lacking dermal lymphatics and distinguish distinct lymphatic clearance patterns in pigs in different body locations and under manual stimulus. Overall, this method has the potential for becoming a noninvasive and quantitative clinical “office test” for lymphatic function assessment.
Anna K. Polomska, Steven T. Proulx, Davide Brambilla, Daniel Fehr, Mathias Bonmarin, Simon Brändli, Mirko Meboldt, Christian Steuer, Tsvetina Vasileva, Nils Reinke, Jean-Christophe Leroux, Michael Detmar
Lymphatic clearance from the skin at the ventral aspect of the torso of awake pigs after bolus intradermal injection of 50 μl indocyanine green (0.0075 mg/ml) in a solution of Kolliphor HS15 (10 mg/ml) with the use of MicronJet600 microneedles.