Inducible overexpression of VEGF-D in obesity expands adipose lymphatics. A: RNA expression for the lymphangiogenic VEGFR-3 ligands Vegf-c and Vegf-d is physiologically elevated in high-fat diet (HFD)--fed obese mouse inguinal adipose tissue compared with chow-fed mice. B: Induction of VEGF-D translation in Adipo-VD mice elevates Vegf-d and lymphatic endothelial cell marker RNAs in inguinal white adipose tissue. C: Brown adipose tissue exhibits higher VEGF-D RNA induction in Adipo-VD mice. D: Immunofluorescence of lymphatic (green; LYVE-1) and blood (red; endomucin) endothelium in inguinal white adipose tissue. E: Quantitation of LYVE-1e and endomucin-positive pixels on inguinal adipose tissue section images. F: Immunofluorescence of lymphatic (green; LYVE-1) and blood (red; endomucin) endothelium in interscapular brown adipose tissue. G: Quantitation of LYVE-1-- and endomucin-positive pixels on brown adipose tissue section images. H: Podoplanin (green) and Prox-1 (red) labeling of lymphatic structures in brown adipose tissue. I: VEGFR-3 (green) labeling of lymphatic structures in white adipose tissue. Blue shows DAPI in all images. J: Whole-mount LYVE-1 immunofluorescence in inguinal white adipose tissue demonstrates LYVE-1+ cells resident in adipose tissue. In Adipo-VD tissue, lymphatic structures form between and around adipocytes. n = 4 (A); n = 8 (B and D--G). *P < 0.05 versus _rtTA. Scale bars: 100 μm (D, F, I, and J); 50 μm (H).