Serum indocyanine green quantification enables objective assessment of lymphatic function

Area of Science:

• Biomedical Engineering
• Physiology
• Medical Diagnostics

Background:

• Secondary lymphedema involves impaired lymphatic drainage, but current diagnostics are limited.
• Existing methods include limb volume measurements and qualitative lymphatic function assessments.

Purpose of the Study:

• To evaluate systemic uptake of intradermal fluorescent tracers as a quantitative biomarker for lymphatic transport.
• To test if serum dye concentrations can serve as a novel diagnostic tool for lymphatic dysfunction.

Main Methods:

• Utilized preclinical models of lymphatic dysfunction: VEGFR3 haploinsufficiency, lymphatic endothelial cell depletion, aging, and surgical injury.
• Administered indocyanine green (ICG) intradermally and measured serum concentrations.
• Correlated ICG serum levels with lymphatic vessel density, lymphatic pumping, and dendritic cell migration.

Main Results:

• Decreased serum ICG concentrations were observed in models with impaired lymphatic function.
• Lower ICG levels correlated with reduced lymphatic vessel density and diminished lymphatic pumping.
• Impaired dendritic cell migration also correlated with decreased serum ICG.

Conclusions:

• Quantification of serum dye concentrations, selectively transported by the lymphatic system, shows promise as a biomarker for lymphatic function.
• This approach may offer a valuable tool for assessing lymphatic transport and diagnosing conditions like secondary lymphedema.