In psoriasis the epidermis, including the subepidermal vascular plexus, grows downwards into the dermis

Area of Science:

• Dermatology
• Vascular Biology
• Histology

Background:

• Psoriatic lesions exhibit elongated and increased intrapapillary capillaries.
• Angiogenesis is the commonly accepted explanation for these vascular changes in psoriasis.

Purpose of the Study:

• To investigate the origin of increased intrapapillary capillaries in psoriatic plaques.
• To differentiate between angiogenesis and vascular inclusion as the cause of capillary changes.

Main Methods:

• Computer-aided three-dimensional reconstructions were utilized.
• Analysis was performed on four patients with chronic plaque-type psoriasis and one healthy volunteer.

Main Results:

• The study found that increased intrapapillary capillaries in psoriasis are not a result of angiogenesis.
• Three-dimensional reconstructions revealed the inclusion of subpapillary blood and lymph capillaries within rete ridges.
• These incorporated vessels, surrounded by rete ridges, mimic the appearance of intrapapillary capillaries.

Conclusions:

• The observed increase in intrapapillary capillaries in psoriatic lesions is an artifact of vascular inclusion, not angiogenesis.
• Lymph capillaries are present within the papillary body of psoriatic lesions.
• Understanding this vascular remodeling is crucial for psoriatic plaque pathogenesis.