The cell cycle in psoriasis: a reappraisal

Area of Science:

• Dermatology
• Cell Biology
• Epidermal Kinetics

Background:

• Current understanding attributes psoriasis to accelerated epidermal cell cycle times.
• This accelerated cycle is believed to cause excessive scaling in psoriatic lesions.

Purpose of the Study:

• To re-evaluate the cell cycle kinetics of epidermal cells in psoriasis.
• To propose a new model for epidermal proliferation in psoriatic lesions.

Main Methods:

• The study challenges the existing model of psoriatic cell division.
• It introduces a new concept of three distinct epidermal cell populations.

Main Results:

• The belief in a significantly shortened cell cycle (457 to 37.5 h) in psoriatic epidermis is refuted.
• Epidermal cells exist in cycling and two non-cycling (G1 or G2 blocked) populations.
• Increased proliferation in psoriasis is mainly due to recruitment/release of non-cycling cells.

Conclusions:

• Germinative epidermal cells are primarily non-cycling, not cycling.
• Focusing on non-cycling cells offers novel therapeutic strategies for psoriasis.
• Treating during remission to maintain non-cycling states may be more effective than treating flare-ups with chemotherapy-like drugs.