Anin vivostudy of the microlymphatics in psoriasis using fluorescence microlymphography

Abstract

Angiogenesis is a recognized event in psoriasis. Previous ultrastructural studies have demonstrated lymphatic capillaries extending high into the dermal papillae. Using the novel method of fluorescence microlymphography which permits visualization of upper dermal initial lymphatics in vivo we tested the hypothesis that lymphangiogenesis exists within plaque psoriasis. Six patients underwent fluorescence microlymphography with fluorescein isothiocyanate-dextran administered intracutaneously within a psoriatic plaque on the leg. Stereological analysis permitted quantification of the lymphatic network opacified both within (lesional) and without (perilesional) the plaque. Results showed a greater spread of tracer from the depot into perilesional skin than into the plaque (P < 0.006). The mean length of lymphatics per unit area at increasing distance from the centre of the depot was also increased for the perilesional skin, 10.5 +/- 1.9/cm2 (mean +/- SEM), compared with lesional skin, 3.06 +/- 0.8/cm (P < 0.001). The cumulative lymphatic length was also greater in perilesional, 22 +/- 7.3 cm2, compared with lesional skin, 3.6 +/- 0.3 cm (P < 0.006). Fluorescence microlymphography has proved to be an effective in vivo technique for the assessment of the dermal microlymphatics in psoriasis. Stereology provided quantitative analysis of the lymphatic network visualized. Overall, there is a greater network of lymphatics in perilesional compared with lesional skin in patients with plaque psoriasis. This finding is at odds with the accepted view that the lymphatic dermal vessels are increased within the psoriatic plaque.

Videocapillaroscopic Findings in the Microcirculation of the Psoriatic Plaque

“…In perilesional compared with lesional skin, fluorescence microlymphography showed a greater network of lymphatics [8]. …”

Hypercholesterolemic Mice Exhibit Lymphatic Vessel Dysfunction and Degeneration

“…These findings point to the need for increased research on the mechanisms that link lymphatic vessels with lipid-related disorders and raise the possibility of a causative role of dyslipidemia in promoting alterations in lymphatic vessels reported in chronic inflammatory disorders that are associated with dyslipidemia, such as rheumatoid arthritis, 48 psoriasis, 49 and certain cancers. …”

Roles of Prostaglandin E 2 –EP3/EP4 Receptor Signaling in the Enhancement of Lymphangiogenesis During Fibroblast Growth Factor-2–Induced Granulation Formation

“…Recent evidence, however, indicates that lymphangiogenesis, similar to angiogenesis, also occurs during certain inflammatory and autoimmune conditions. Psoriasis, a chronic inflammatory skin disease, is characterized by extensive lymphangiogenesis, 1 and lymphatic hyperplasia is frequently observed in rejected renal transplants from patients with this condition. 2,3 Furthermore, bacterial infection of the airway epithelia of mice induced intense lymphangiogenesis and upregulated vascular endothelial growth factors (VEGF)-C and VEGF-D. 4 After inflammation has been resolved, new lymphatic networks form a drainage system for fluid and immune cells.…”