Quantification of the initial lymphatic network in normal human forearm skin using fluorescence microlymphography and stereological methods.

Fluorescence microlymphography enables the visualization of the initial lymphatic network in human dermis in vivo. In order to determine which objective, measurable parameters are likely to be of value in future studies, microlymphangiograms were obtained from normal forearm skin of eight men and nine women of a range of ages and analyzed stereologically to calculate: (1) lymphatic length density at a specified radial distance, r, from the site of injection of the fluorescent dye (LDr, cm-1); (2) maximum lymphatic density (LDmax, cm-1); (3) total length of filled lymphatic (LL, cm); (4) maximum radial spread of vessels (mm). There was no significant difference between the right and left arms for peak LDr, LDmax, LL, or spread. Mean values (+/-SD) for the right and left arms combined (n = 24) were 13.34 +/- 7.61 cm-1; 19.31 +/- 8.96 cm-1; 12.04 +/- 10.04 cm; and 7.58 +/- 3.30 mm, respectively. Unexpectedly, three of the four parameters were significantly lower in women compared to men. For women LDmax was 30% lower than for men (P = 0.04), LL was 59% lower (P = 0.032), and spread was 39% lower (P = 0.007). Peak LDr did not differ significantly. Stereological analysis of fluorescent microlymphangiograms enables quantification of the dermal initial lymphatic network and hence the objective study of the influence of gender, age, and disease (including treatment interventions).