Abnormal mural cell recruitment in lymphatic capillaries: a common pathological feature in chronic lymphedematous skin?

OBJECTIVES

This study aimed to explore the structural and functional characteristics of dermal lymphatic capillaries in patients with chronic LE, specifically focused on the mural cells that are associated with skin lymphatics.

METHODS

Forty-four patients (30 primary LE and 14 secondary LE) and eight healthy controls were enrolled in this study. Genetic analysis of the FOXC2 was performed in 18 patients with primary LE. Full-thickness skin was excised and immunohistologically stained for podoplanin and α-SMA. The proportions of α-SMA+ Lv (α-SMA+ Lv%) were calculated. Lymphatic vascular function was assessed by indocyanine green lymphography.

RESULTS

Analysis of FOXC2 revealed two mutations in two patients with LDs. Histologically, thirty-nine patients exhibited increased α-SMA+ mural cell coverage of lymphatic capillaries. The α-SMA+ Lv% values in the superficial and deep dermis in patients with primary and secondary LE were significantly higher than in the control group. Compared with imaging findings in healthy limbs, in which the collecting lymphatics were clearly visualized, lymphedematous extremities all exhibited dermal backflow.

CONCLUSIONS

Abnormal recruitment of mural cells in dermal lymphatic capillaries is a common pathological event in chronic LE, and may play a role in disease evolution.